IPAC2014 - List of Keywords (simulation)

Paper	Title	Other Keywords	Page
MOZA01	Ultralow Emittance Beam Production based on Doppler Laser Cooling and Coupling Resonance	laser, ion, coupling, solenoid	28
	A. Noda, M. Nakao NIRS, Chiba-shi, Japan M. Grieser MPI-K, Heidelberg, Germany Z.Q. He FRIB, East Lansing, Michigan, USA Z.Q. He TUB, Beijing, People's Republic of China K. Jimbo Kyoto University, Kyoto, Japan H. Okamoto, K. Osaki HU/AdSM, Higashi-Hiroshima, Japan A.V. Smirnov JINR, Dubna, Moscow Region, Russia H. Souda Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan H. Tongu Kyoto ICR, Uji, Kyoto, Japan Y. Yuri JAEA/TARRI, Gunma-ken, Japan
	Funding: Work supported by Advanced Compact Accelerator Development project by MEXT of Japan. It is also supported by GCOE project at Kyoto University, “The next generation of Physics-Spun from Universality" Doppler laser cooling has been applied to low-energy (40 keV) Mg ions together with the resonant coupling method* at the S-LSR at ICR, Kyoto University,. The S-LSR storage ring has a high super periodicity of 6, which is preferable from the beam dynamical point of view. At S-LSR one dimensional ordering of proton beam was already realized for the first time*. Active three dimensional laser cooling has been experimentally demonstrated for ions with un-negligible velocity (v/c=0.0019, where c is the light velocity) for the first time. Utilizing the above mentioned characteristics of S-LSR, an approach to realize ultralow emittances has been pursuit. To suppress heating effects, due to intra-beam scattering, the circulating ion beam intensity was reduced by scraping and beam emittances of 1.3·10^-11 pi m·rad and 8.5·10^-12 pi m·rad (normalized) have been realized for the horizontal and vertical directions, respectively with the 40 keV Mg ion beam at a beam intensity of ~10⁴, which is the lowest emittance ever attained by laser cooling. From MD computer simulations, it is predicted that reduction of the ion number to about 10³ is needed to realize a crystalline string. H. Okamoto, A.M. Sessler, D. Moehl, Phys. Rev. Lett. 72, 397 (1994). ** T. Shirai et. al., Phys. Rev. Lett. 98, 204801 (2007).
	Slides MOZA01 [13.336 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOCB01	Beam-induced Quench Tests of LHC Magnets	quadrupole, collimation, experiment, beam-losses	52
	M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto CERN, Geneva, Switzerland
	At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.
	Slides MOOCB01 [2.737 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO002	The Momentum Distribution of the Decelerated Drive Beam in CLIC and in the Two-beam Test Stand at CTF3	emittance, operation, distributed, controls	62
	Ch. Borgmann, M. Jacewicz, J. Ögren, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	We present analytical calculations of the momentum spectrum of the drive beam in CLIC and the CLIC Test Facility CTF3 after part of its kinetic energy is converted to microwaves for the acceleration of the main beam. The resulting expressions are used to determine parameters of the power conversion process in the Power Extraction Structure (PETS) installed in the Two-beam Test Stand in CTF3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO002
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO007	GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders	GPU, luminosity, collider, electron	77
	B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang JLab, Newport News, Virginia, USA M. Aturban, D. Ranjan, M. Zubair ODU CS, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO012	Simulating Fast Beam-Ion Instability Studies in FFAG-Based ERHIc Rings	electron, ion, linac, lattice	83
	G. Wang, V. Litvinenko, Y. Luo BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In an electron accelerator, ions generated from the residual gas by the circulating electrons act back to the trailing electrons. Under unfavorable conditions this feed-back can cause unstable motion of the electron bunches, the process known as the fast beam ion instability. Current eRHIC design has two FFAG rings transporting 21 electron beams at 11 different energies. In this study, we use numerical simulation to investigate the fast ion instability in this complicated system, compare the simulation results with theory and discuss possible measures to mitigate the instability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO012
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO019	Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV	proton, beam-losses, quadrupole, operation	105
	N.V. Shetty, B. Auchmann, V. Chetvertkova, A. Lechner, A. Priebe, M. Sapinski, A.P. Verweij, D. Wollmann CERN, Geneva, Switzerland
	In 2013, beam-induced quench tests with 4 TeV protons were performed to probe the quench level of LHC arc quadrupole magnets at timescales corresponding to millisecond beam losses and steady-state losses. As the energy deposition in magnet coils cannot be measured directly, this study presents corresponding FLUKA simulations as well as estimates of quench levels derived with the QP3 code. Furthermore, beam loss monitor (BLM) signals were simulated and benchmarked against the measurements. Simulated and measured BLM signals are generally found to agree within 30 percent.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO020	FLUKA Simulation of Particle Fluences to ALICE due to LHC Injection Kicker Failures	injection, kicker, high-voltage, detector	109
	N.V. Shetty, C. Bracco, A. Di Mauro, A. Lechner, E. Leogrande, J.A. Uythoven CERN, Geneva, Switzerland
	The counter-rotating beams of the LHC are injected in insertion regions which also accommodate the ALICE and LHCb experiments. An assembly of beam absorbers ensures the protection of machine elements in case of injection kicker failures, which can affect either the injected or the stored beam. In the first years of LHC operation, secondary particle showers due to beam impact on the injection beam stopper caused damage to the MOS injectors of the ALICE silicon drift detector as well as high-voltage trips in other ALICE subdetectors. In this study, we present FLUKA simulations of particle fluences to the ALICE cavern for injection failures encountered during operation. Two different cases are reported, one where the miskicked beam is fully intercepted and one where the beam grazes the beam stopper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO020
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO021	Power Deposition in LHC Magnets With and Without Dispersion Suppressor Collimators Downstream of the Betatron Cleaning Insertion	proton, dipole, operation, collimation	112
	A. Lechner, B. Auchmann, R. Bruce, F. Cerutti, P.P. Granieri, A. Marsili, S. Redaelli, N.V. Shetty, E. Skordis, G.E. Steele, A.P. Verweij CERN, Geneva, Switzerland
	The power deposited in dispersion suppressor (DS) magnets downstream of the LHC betatron cleaning insertion is governed by off-momentum protons which predominantly originate from single-diffractive interactions in primary collimators. With higher beam energy and intensities anticipated in future operation, these clustered proton losses could possibly induce magnet quenches during periods of short beam lifetime. In this paper, we present FLUKA simulations for nominal 7 TeV operation, comparing the existing layout with alternative layouts where selected DS dipoles are substituted by pairs of shorter higher-field magnets and a collimator. Power densities predicted for different collimator settings are compared against present estimates of quench limits. Further, the expected reduction factor due to DS collimators is evaluated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO027	Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings	impedance, coupling, kicker, damping	125
	C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain M.J. Barnes, H.A. Day CERN, Geneva, Switzerland F. Toral CIEMAT, Madrid, Spain
	The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO029	Feed Forward Orbit Correction in the CLIC Ring to Main LINAC Transfer Lines	emittance, kicker, extraction, collimation	131
	R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven CERN, Geneva, Switzerland
	The emittance growth in the betatron collimation system of the 27 km long transfer lines between the CLIC damping rings and the main LINAC depends strongly on the transverse orbit jitter. The resulting stability requirements of the damping ring extraction elements seem extremely difficult to achieve. Position and angle feed forward systems in these long transfer lines bring the specified parameters of the extraction elements within reach. The designs of the optics and feed forward hardware are presented together with tracking simulations of the systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO033	Design and Feasibility Study of a Transverse Halo Collimation System for ATF2	wakefield, collimation, background, betatron	145
	N. Fuster-Martínez Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France A. Faus-Golfe, J. Resta-López IFIC, Valencia, Spain K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work supported by FPA2010-21456-C02-01 and by i-link 0704 This paper presents the design of a halo collimation system for the ATF2 beamline. The main objective is the reduction of background noise that limits the performance of key diagnostic devices around the final focal point (IP), especially the Shintake Monitor (IPBSM) used for measuring the nanometer level vertical beam sizes and the future Diamond Sensor (DS) for measuring the beam halo. Beam tracking simulations have been performed to optimize the position and characteristics of the halo collimation devices. Furthermore the collimator wakefield-induced effect is being studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO035	Update on Nonlinear Collimation Schemes for the LHC	collimation, sextupole, optics, betatron	151
	J. Resta-López Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Faus-Golfe, L. Lari, J. Resta-López IFIC, Valencia, Spain
	Funding: FP7 HL-LHC Grant Agreement 284404 In this paper we review the status of the studies on nonlinear collimation schemes for the LHC. Concretely we describe the design of a nonlinear optics for betatron cleaning in IR7. The aim is to investigate alternative nonlinear collimation systems to reduce the collimator-induced impedance that may limit the beam intensity towards the LHC luminosity upgrade. The performance of the LHC nonlinear collimation system is studied by means of tracking simulations and compared with the present LHC system. Furthermore, the advantages and possible limitations of such nonlinear collimation scheme are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO036	Beam Life Time and Stability Studies for ELENA	electron, antiproton, emittance, vacuum	154
	J. Resta-López, O. Karamyshev, D. Newton, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev, D. Newton, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom J. Resta-López IFIC, Valencia, Spain
	Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1. The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. At such low energies it is very important to carefully take contributions from electron cooling and heating effects (e.g. on the residual gas) into account. Detailed investigations into the ion kinetics under consideration of effects from electron cooling and scattering on the residual gas have been carried out using the BETACOOL code. In this contribution a consistent explanation of the different physical effects acting on the beam in ELENA is given. Beam lifetime, equilibrium momentum spread and emittance are all estimated based on numerical simulations. Finally, optimum machine settings are presented as a result of optimization studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO036
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO037	Collimator Fast Failure Losses for Various HL-LHC Configurations	optics, collimation, kicker, luminosity	157
	L. Lari, R. Bruce, S. Redaelli CERN, Geneva, Switzerland L. Lari IFIC, Valencia, Spain
	Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 The upgrade of the Large Hadron Collider (LHC), in terms of beam intensity and energy, implies an increasing risk of severe damage in particular in case of fast failures losses. For this reason, efforts were put in developing simulation tools to allow studies of asynchronous dump accident, including realistic failure cases for collimator settings and machine parameters like orbit and optics. The scope of these studies is to understand realistic beam loads in different collimators, in order to improve the actual LHC collimator system design, to provide feedbacks on optic design and to evaluate different mitigation actions. Simulations were set up with a modified SixTrack collimation routine able to simulate erroneous firing of a single dump kicker or the simultaneous malfunction of all the 15 kickers. In such a context, results are evaluated from the whole LHC collimation system point of view.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO039	Integrated Simulation Tools for Collimation Cleaning in HL-LHC	collimation, scattering, proton, lattice	160
	R. Bruce, C. Bracco, F. Cerutti, A. Ferrari, A. Lechner, A. Marsili, A. Mereghetti, D. Mirarchi, P.G. Ortega, D. Pastor Sinuela, S. Redaelli, A. Rossi, B. Salvachua, V. Vlachoudis CERN, Geneva, Switzerland R. Appleby, J. Molson, M. Serluca UMAN, Manchester, United Kingdom R.W. Aßmann DESY, Hamburg, Germany R.J. Barlow, H. Rafique, A.M. Toader University of Huddersfield, Huddersfield, United Kingdom S.M. Gibson, L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom L. Lari IFIC, Valencia, Spain C. Tambasco University of Rome La Sapienza, Rome, Italy
	The Large Hadron Collider is designed to accommodate an unprecedented stored beam energy of 362~MJ in the nominal configuration and about the double in the high-luminosity upgrade HL-LHC that is presently under study. This requires an efficient collimation system to protect the superconducting magnets from quenches. During the design, it is therefore very important to accurately predict the expected beam loss distributions and cleaning efficiency. For this purpose, there are several ongoing efforts in improving the existing simulation tools or developing new ones. This paper gives a brief overview and status of the different available codes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO040	Collimation Cleaning for HL-LHC Optics Scenarios with Error Models	collimation, alignment, optics, dipole	163
	A. Marsili, R. Bruce, S. Redaelli CERN, Geneva, Switzerland
	Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 The upgrade of the LHC collimation system in view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) foresees, amongst other scenarios, local collimation in the dispersion suppressors (DS) of IR7. Layouts have been worked out which rely on using stronger and short bending dipoles to free space for a collimator in the cold DS. In this paper, the effectiveness of the proposed layouts is studied with different imperfection models such as collimator alignment, jaw tilt and surface errors, optics errors and aperture imperfections. The effect of local DS collimation on the global losses around the ring is also addressed for different optics configurations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO041	Multi-turn Tracking of Collision Products at the LHC	proton, luminosity, betatron, optics	166
	A. Marsili, R. Bruce, F. Cerutti, L.S. Esposito, S. Redaelli CERN, Geneva, Switzerland
	Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 The luminosity expected at the interaction points in LHC at 7 TeV will be unprecedented, up to 1034 cm−2 s−1 . Part of the debris produced by the collisions is lost locally im- mediately downstream the Interaction Point (IP), in the matching section and dispersion suppressor. In this paper, the dynamics of collision debris protons is discussed. First, the loss distributions close to the collision points, simulated with two codes – SixTrack and FLUKA – are compared for different layout configurations. Then, SixTrack is used to simulate the fraction of protons that have undergone inelastic interactions with smaller energy and and betatron offsets, which could travel for several turns around the ring and might be lost in other collimation insertions. A preliminary comparison is made between the resulting loss distribution and measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO042	Cleaning Performance with 11T Dipoles and Local Dispersion Suppressor Collimation at the LHC	dipole, optics, collimation, proton	170
	R. Bruce, A. Marsili, S. Redaelli CERN, Geneva, Switzerland
	The limiting location of the present LHC machine in terms of losses on cold magnets are the dispersion suppressors downstream of the betatron collimation insertion (IR7). These losses are dominated by off-energy protons that have by-passed the upstream secondary collimation system but are lost where the dispersion starts to rise. A solution under consideration for intercepting these losses is the addition of new collimators in the dispersive area. This paper discusses first a proposition for the new layout in the DS, where space is made for the new collimators by replacing an existing dipole by shorter and stronger magnets. Furthermore, simulations with SixTrack are presented, which quantify the gain in cleaning from the new collimators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO043	Handling 1 MW Losses with the LHC Collimation System	collimation, beam-losses, betatron, proton	174
	B. Salvachua, R. Bruce, F. Carra, M. Cauchi, E.B. Holzer, W. Höfle, D. Jacquet, L. Lari, D. Mirarchi, E. Nebot Del Busto, S. Redaelli, A. Rossi, M. Sapinski, R. Schmidt, G. Valentino, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland M. Cauchi UoM, Msida, Malta L. Lari IFIC, Valencia, Spain
	Funding: Research supported by EU FP7 HiLumi LHC (Grant agree. 284404) The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking from the betatron collimation system and represent the main limitation for the halo cleaning. In 2013, quench tests were performed at 4 TeV to improve the quench limit estimates, which determine the maximum allowed beam loss rate for a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the magnets did not quench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO045	Beam Delivery Simulation: BDSIM - Development & Optimisation	lattice, collider, background, detector	182
	L.J. Nevay, S.T. Boogert, H. Garcia, S.M. Gibson, R. Kwee-Hinzmann, J. Snuverink JAI, Egham, Surrey, United Kingdom L.C. Deacon UCL, London, United Kingdom
	Funding: Research supported by FP7 HiLumi LHC - grant agreement 284404. Beam Delivery Simulation (BDSIM) is a Geant4 and C++ based particle tracking code that seamlessly tracks particles through accelerators and detectors, including the full range of particle interaction physics processes from Geant4. BDSIM has been successfully used to model beam loss and background conditions for many current and future linear accelerators such as the Accelerator Test Facility 2 (ATF2) and the International Linear Collider (ILC). Current developments extend its application for use with storage rings, in particular for the Large Hadron Collider (LHC) and the High Luminosity upgrade project (HL-LHC). This paper presents the latest results from using BDSIM to model the LHC as well as the developments underway to improve performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO045
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO046	Comparison of MERLIN/SixTrack for LHC Collimation Studies	collimation, optics, scattering, proton	185
	M. Serluca, R. Appleby, J. Molson UMAN, Manchester, United Kingdom R.J. Barlow, H. Rafique, A.M. Toader University of Huddersfield, Huddersfield, United Kingdom R. Bruce, A. Marsili, S. Redaelli, B. Salvachua CERN, Geneva, Switzerland C. Tambasco University of Rome La Sapienza, Rome, Italy
	Simulations of the LHC collimation system have been carried out in previous years with the well known SixTrack code with collimation features. MERLIN is a C++ accelerator physics library that has been extended to perform collimation studies. The main features of the code are: its modular nature, allowing the user to easily implement new physics processes such as resistive wakefields and synchrotron radiation, improved scattering routines and the MPI protocol for parallel execution. MERLIN has been configured to use the same scattering routines as SixTrack in order to benchmark the code for the LHC collimation system. In this paper we present a detailed comparison between MERLIN and SixTrack for optics and cleaning inefficiency calculation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO046
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO061	Study of the Beam Lifetime at the Synchrotron Light Source DELTA	scattering, electron, synchrotron, vacuum	222
	M.A. Jebramcik, H. Huck, S. Khan, R. Molo DELTA, Dortmund, Germany
	DELTA is a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The beam lifetime, which is a critical issue for user operation of a light source, was studied experimentally and by simulation for different operation modes, i.e. single-bunch and multibunch fill patterns and for different beam currents. The electron loss rate is dominated by residual-gas scattering (Coulomb scattering and Bremsstrahlung) and by electron-electron scattering (Touschek effect). Since these processes depend in different ways on the momentum acceptance of the storage ring, a variation of the RF cavity voltage allows to disentangle their respective contributions to the total loss rate. The experimental results lead to a consistent picture for different operation modes with a characteristic dependence of the residual-gas pressure on the beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO061
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO068	Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation	synchrotron, storage-ring, operation, optics	237
	P. Schönfeldt, A. Borysenko, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, S. Naknaimueang, M. Schuh, M. Schwarz, J.L. Steinmann KIT, Karlsruhe, Germany
	The ANKA electron storage ring of the Karlsruher Institute of Technology (KIT, Germany) is regularly operated in low-alpha mode to produce short bunches for the generation of coherent synchrotron radiation (CSR). This paper evaluates systematic bunch length measurements taken in low-alpha operation of the ANKA storage ring. Above the bursting threshold not only the emission of CSR occurs in bursts, but also a continuous fluctuation of the bunch's length is observed. The measurements were carried out using concurrent multi turn (using a streak camera) as well as single shot (using electro-optical spectral decoding) methods. Furthermore, we compare information obtained on the fluctuation to simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO068
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO086	On-line Beam Control with Ocelot at Siberia-2	controls, software, closed-orbit, dipole	289
	S.I. Tomin, A.G. Valentinov NRC, Moscow, Russia
	Siberia-2 is a synchrotron light source with electron beam energy up to 2.5GeV, currently undergoing upgrade of controls hardware and software. Ocelot, an accelerator physics framework, was integrated with the new orbit correction system for high level beam control. We describe the steps taken for simulation studies of orbit correction strategies on a virtual machine model, integration of the software into the control system and experimental results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO086
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO090	Top-up Operation at ALBA Synchrotron Light Source	injection, operation, radiation, storage-ring	301
	M. Pont, G. Benedetti, J. Moldes, R. Muñoz Horta, A. Olmos, F. Pérez CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The ALBA light source has been operating in decay mode since May 2012. Now it is ready for top-up operation, which should become the standard operation mode for users from mid 2014. In this paper we are going to summarise the different steps that have taken place before the start of top-up operation: radiation safety simulations and measurements, upgrade of hardware and software interlocks, control software and injection optimisation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO090
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO108	Lattice and Start-to-end Simulation of the Mainz Energy Recovering Superconducting Accelerator MESA	lattice, linac, experiment, optics	346
	R.G. Heine, K. Aulenbacher, F. Schlander, D. Simon IKP, Mainz, Germany
	Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA" The institute for nuclear physics (IKPH) at Mainz University is designing a multi turn energy recovery linac for particle physics experiments . We present the current status of the lattice development of MESA together with a PARMELA start to end simulation. R. Heine, K. Aulenbacher, and R. Eichhorn: MESA-Sketch of an Energy Recovery LINAC for Nuclear Physics Experiments at Mainz, Proc. of the IPAC2012, New Orleans, Louisiana, USA, p. 1993-1995.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO108
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO109	Beam Loss Studies for the KEK Compact-ERL	scattering, electron, cavity, beam-losses	349
	O. Tanaka, T. Furuya, K. Harada, N. Nakamura, H. Sakai, M. Shimada, K. Umemori KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan
	Beam losses due to eﬀects of Touschek, residual gas, intra-beam scattering, and field emission were studied for the KEK compact Energy Recovery Linac (cERL), which is now under commissioning. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beamline for the future 3GeV ERL project. The goal is to achieve a safety low-emittance and high-current beams operation which can help contribute to the beam loss study under 3GeV ERL project. We used existing and modiﬁed ELEGANT routine to perform the simulations. We also developed a MATLAB data analysis algorithm to handle the large amount of information that is outputted from the program. The data obtained then compared with the theoretical estimation to judge the computation’s accuracy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO109
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO114	Particle Tracking Simulations with FLUKA for DESY FLASH and EXFEL	radiation, electron, neutron, photon	363
	V.G. Khachatryan, V.H. Petrosyan, A. Sargsyan, A.V. Tsakanian CANDLE SRI, Yerevan, Armenia
	The objective of the study is the simulation of the produced secondary radiation properties when the electron beam halo particles hit collimator walls. Using particle tracking simulation code FLUKA the European XFEL electron beam interaction with the titanium collimator and copper absorber of the undulator intersections as well as FLASH beam interaction with the tapered collimator were simulated. Absorbed dose spatial distribution in the material of the collimators was simulated for the total secondary radiation and its important photon and neutron components. Residual dose rate after irritation of the collimator material by the electron beam was calculated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO114
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME002	Simulation of the Thermal Deformation and the Cooling of a Four-rod Radio Frequency Quadrupole	rfq, radio-frequency, quadrupole, radio-frequency-quadrupole	376
	B. Masschaele, H. De Gersem, T. Roggen KU Leuven, Kortrijk, Belgium H. Podlech IAP, Frankfurt am Main, Germany D. Vandeplassche SCK•CEN, Mol, Belgium
	Funding: This work is supported by the European Atomic Energy Community’s Seventh Framework Programme under grant agreement nr. 269565 (MAX project). A four-rod radio frequency quadrupole (RFQ) contains four modulated rods kept in place by a number of stems and fixed within a resonating cavity. The position and the modulation of the rods determines the focusing and accelerating properties of the RFQ. The resonating field induces currents, and by that Joule losses, in the stems, rods and tuning plates. The temperature increase causes a mechanical deformation which may lead to a deteriorated performance of the RFQ. The temperature increase is kept small by cooling the rods and stems. A new layout of cooling channels has been proposed. The paper reports about coupled electromagnetic, fluid-dynamic, thermal and structural dynamic field simulations carried out for predicting the mechanical deformation of the stems and the rods. The results for the four-rod RFQ planned for the MYRRHA proton accelerator indicate a change of 47 μm of the distance between the rods when cooling water with a velocity of 3 m/s is applied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME002
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME003	Radio Frequency Quadrupole Surrogate Field Models Based on 3D Electromagnetic Field Simulation Results	rfq, multipole, quadrupole, electromagnetic-fields	379
	T. Roggen, H. De Gersem, B. Masschaele KU Leuven, Kortrijk, Belgium W. Ackermann, S. Franke, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This research is funded by grant ”KUL 3E100118” ”Electromagnetic Field Simulation for Future Particle Accelerators”, Project FP7-Euratom No. 269565 and the Belgian Nuclear Research Centre (SCK•CEN) Surrogate field models for the different sections of a Radio Frequency Quadrupole (RFQ) are developed, identified on the basis of finite element (FE) simulation and embedded in a moment method beam dynamics simulation code. The models are validated for both theoretical and realistic RFQ designs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME004	RFQ Solver based on the Method of Moments	rfq, linac, impedance, quadrupole	382
	C. Raucy, C.V.G. Craeye UCL, Louvain-la-Neuve, Belgium D. Vandeplassche SCK•CEN, Mol, Belgium
	Funding: SCK•CEN The aim of this research is to improve the accuracy and the simulation time of solvers devoted to Radio Frequency Quadrupoles (RFQ). The Method of Moments is a full-wave method used to solve scattering problems. Its main advantage over FE or FDTD solvers is that unknowns are limited to the boundaries of the object. The resulting dense system of equations can be solved very rapidly with the help of domain-decomposition approaches (e.g. Macro Basis Functions), especially when the level of detail is very fine compared to the wavelength, which is definitely the case for RFQ’s. Such a method however needs a first regularization method to overcome the low-frequency breakdown in order to compute the Macro Basis Functions. The respective field contributions of different parts of the global structure (e.g. rods vs. stems) can also easily be finely investigated. Numerical results will be presented based on the Myrrha RFQ. The low-frequency breakdown issue due to the very fine mesh will be discussed and a solution based on the so-called Loop-Tree* decomposition will be detailed. * Ozdemir, N.A.; Gonzalez-Ovejero, D.; Craeye, C., IEEE Tr.AP, vol.61, no.4, pp.2088, 2098, April 2013 ** Andriulli, F.P., IEEE Tr.AP, vol.60, no.5, pp.2347, 2356, May 2012
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME004
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME005	Simulation of the Extraction and Transport of a Beam from the SILHI Source with the Warp Code	ion, plasma, extraction, space-charge	385
	A. Chancé, N. Chauvin CEA/DSM/IRFU, France
	In a low energy beam transfer (LEBT) line, space charge effects are dominant and make the motion of the particles strongly non-linear. So, the beam dynamics is directly dependent on the 6D distribution of the particles after the ion source extraction system. It is thus essential to simulate accurately the source extraction region and the space charge compensation after it to try to reach an agreement between the simulations and the measurements. Generally, the ion source extraction system is simulated with electrostatic codes (often using simple model for space charge) from which the 6D beam distribution is derived. Then, this distribution can be used as an initial condition to simulate the beam transport in the LEBT with a time dependent PIC code that takes into account space charge compensation. We propose here to simulate accurately the SILHI source extraction system with the Warp and AXCEL-INP codes. The SILHI ion source will be quickly presented and some simulations results will be given and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME005
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME008	3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector	laser, cathode, gun, emittance	391
	Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: work supported by DESY, Hamburg and Zeuthen sites The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra *. Computer Simulation Technology AG, website: http://www.cst.com/ ** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME008
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME010	A MAD-X Model of the HIT Accelerator	ion, synchrotron, dipole, controls	397
	R. Cee, M. Galonska, T. Gläßle, Th. Haberer, K. Höppner, A. Peters, S. Scheloske HIT, Heidelberg, Germany
	For a medical accelerator facility like the Heidelberg Ion-Beam Therapy Centre (HIT) an online simulation tool with read and write access to the control system and the database is essential for effective beam alignment and beam spot size adjustment at the patient position. Since the commissioning of HIT the simulation programme Mirko from GSI Darmstadt has been in use for the simulation of the beamlines and the synchrotron. While Mirko fully complies with the demands and is still in regular use, the long-term support of the HIT-Mirko derivate cannot be guaranteed. We have therefore started to set up a new simulation environment based on the MAD-X programme from CERN. In a first step we built a MAD-X model of the HIT accelerator using the MAD-X export function of Mirko. The resulting sequences were transformed and extended into executable MAD-X files. The simulation results were validated against Mirko and a good agreement of the calculated beam envelopes could be achieved. Works on the graphical user interface (GUI) for visualisation of and interaction with the beam envelopes and the link to the control system are in progress.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME011	Matrix Integration of ODEs for Spin-orbit Dynamics Simulation	lattice, operation, quadrupole, resonance	400
	A.N. Ivanov, Y. Senichev FZJ, Jülich, Germany
	MODE (Matrix integration of Ordinary Differential Equations) is a software package that provides nonlinear matrix maps building for spin-orbit beam dynamics simulation. In this article we briefly describe the developed integrated development environment features and present computational comparison with other simulation tools. MODE mathematical model is based on Newton-Lorentz and T-BMT equations that are expanded to Taylor series up to the necessary order of nonlinearity. The numerical algorithm is based on matrix presentation of Lie propagator. Spin-orbit simulation results of MODE are compared with results of COSY Infinity and OptiM. MODE provides a flexible graphic user interface, code auto complete technology and visual designer for accelerators. There is also a possibility to generate codes in different programming languages and parallelization techniques.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME012	A New Tool for Automated Orbit and Spin Motion Analysis	lattice, experiment, software, storage-ring	403
	D. Zyuzin FZJ, Jülich, Germany
	There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME012
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME013	A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries	rfq, space-charge, electron, ion	406
	G. Pöplau, C. Potratz COMPAEC e.G., Rostock, Germany
	Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME013
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME014	Automated Mode Recognition Algorithm for Accelerating Cavities	cavity, coupling, polarization, dipole	409
	K. Brackebusch, T. Galek, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by Federal Ministry for Research and Education BMBF under contract 05K13HR1. Eigenmode simulations of accelerating structures often involve a large number of computed modes that need to be catalogued and compared. In order to effectively process all the information gathered from eigenmode simulations a new algorithm was developed to automatically recognize modes’ field patterns. In this paper we present the principles of the algorithm and investigate its applicability by means of different single and multi cell cavities. The highest achievable order of correctly recognized modes is of particular interest.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME014
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME018	Quantification of Geometric Uncertainties in Single Cell Cavities for BESSY VSR using Polynomial Chaos	cavity, HOM, linac, SRF	415
	J. Heller, T. Flisgen, C. Schmidt, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Federal Ministry for Research and Education Germany under contract 05K13HR1 The electromagnetic properties of SRF cavities are mostly determined by their shape. Due to fabrication tolerances, tuning and limited resolution of measurement systems, the exact shape remains uncertain. In order to make assessments for the real life behaviour it is important to quantify how these geometrical uncertainties propagate through the mathematical system and influence certain electromagnetic properties, like the resonant frequencies of the structure's eigenmodes. This can be done by using non-intrusive straightforward methods like Monte-Carlo (MC) simulations. However, such simulations require a large number of deterministic problem solutions to obtain a sufficient accuracy. In order to avoid this scaling behaviour, the so-called polynomial chaos (PC) expansion is used. This technique allows for the relatively fast computation of uncertainty propagation for few uncertain parameters in the case of computationally expensive deterministic models. In this paper we use the PC expansion to quantify the propagation of uncertain geometry on the example of single cell cavities used for BESSY VSR as well as to compare the obtained results with the MC simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME019	Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches	space-charge, electron, ion, electromagnetic-fields	418
	D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency. * J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME022	Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna	plasma, ion, operation, experiment	424
	H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu USTC/NSRL, Hefei, Anhui, People's Republic of China
	A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME022
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME023	A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma	electron, cyclotron, plasma, experiment	427
	X.F. Li, D.Z. Chen, D. Li, H.K. Yue HUST, Wuhan, People's Republic of China
	A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME025	New Possibilities of MultP-M Code	multipactoring, electron, RF-structure, operation	433
	M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov MEPhI, Moscow, Russia
	Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME025
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME026	IBS Simulations with Compute Unified Device Architecture (CUDA) Technology	scattering, GPU, factory, electron	436
	S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture). J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME027	Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders	collider, linear-collider, beam-beam-effects, positron	439
	M.A. Boronina, V.D. Korneev, V.A. Vshivkov ICM&MG SB RAS, Novosibirsk, Russia
	We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME029	Simulation of Low Energy Charged Particle Beams	electron, cyclotron, extraction, quadrupole	442
	O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME032	PIC Simulations in Low Energy Part of PIP-II Proton Linac	rfq, emittance, linac, proton	448
	G.V. Romanov Fermilab, Batavia, Illinois, USA
	The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME033	Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code	electron, collider, gun, solenoid	451
	G. Stancari Fermilab, Batavia, Illinois, USA V. Moens EPFL, Lausanne, Switzerland S. Redaelli CERN, Geneva, Switzerland
	Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404. Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME033
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME035	Current Status of the GPU-Accelerated ELEGANT	GPU, operation, acceleration, linac	454
	I.V. Pogorelov, K.M. Amyx, J.R. King Tech-X, Boulder, Colorado, USA M. Borland, R. Soliday ANL, Argonne, Ilinois, USA
	Funding: Work supported by the DOE Office of Science, Office of Basic Energy Sciences grant No. DE-SC0004585, and in part by Tech-X Corporation. Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large-scale tracking simulations. This presentation is an update on the current status of our work on accelerating Argonne National Lab’s particle accelerator simulation code ELEGANT using CUDA-enabled GPU. We summarize the performance of beamline elements ported to GPU, and discuss optimization techniques for some important collective effects kernels, in particular our methods of avoiding costly thread contention. We also present preliminary results of a scaling study of the GPU-accelerated version of the code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME035
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME037	The Development of Stochastic Processes in COSY Infinity	scattering, emittance, lattice, controls	457
	J.D. Kunz IIT, Chicago, Illinois, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work supported by U.S. Department of Energy. COSY Infinity is an arbitrary-order beam dynamics simulation code. It can determine high-order transfer maps of combinations of particle optical elements. New features are being developed for inclusion in COSY to follow the distribution of particles through matter. To study in detail the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte-Carlo approach in which transfer map methods describe the average behavior of the particles including energy loss, and Monte-Carlo methods are used to provide small corrections to the predictions of the transfer map accounting for the stochastic nature of scattering and straggling of particles. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed will aid the optimization of muon cooling channels. Progress on the development of the required algorithms is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME038	Space Charge Simulation in COSY using The Fast Multipole Method	space-charge, emittance, multipole, collider	460
	B.T. Loseth, M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Fermilab, Batavia, Illinois, USA H. Zhang JLab, Newport News, Virginia, USA
	A method is implemented in COSY Infinity that allows the computation of space charge effects of arbitrary and large distributions of particles in an efficient and accurate way based on a variant of the Fast Multipole Method (FMM). It relies on an automatic multigrid-based decomposition of charges in near and far regions and the use of high-order differential algebra methods to obtain decompositions of far fields that lead to an error that scales with a high power of the order. Given an ensemble of N particles, the method allows the computation of the self-fields of all particles on each other with a computational expense that scales as O(N). Furthermore, the method allows the computation of all high-order multipoles of the space charge fields that are necessary for the computation of high-order transfer maps and all resulting aberrations. Space charge effects are crucial in modeling the latter stages of the six-dimensional (6D) cooling channel for the Muon Collider. Results of simulating the 6D cooling channel for the Muon Collider using the FMM method and other tools and improvements implemented for ionization cooling lattices are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME038
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME043	Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices	plasma, cavity, electron, ion	466
	K. Yu SBU, Stony Brook, USA M. Chung, A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA B.T. Freemire IIT, Chicago, Illinois, USA V. Samulyak BNL, Upton, Long Island, New York, USA V. Samulyak SUNY SB, Stony Brook, New York, USA
	Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed. * kwangmin.yu@stonybrook.edu ** rosamu@bnl.gov
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME047	Comparison of the Results of a Hydrodynamic Tunneling Experiment with Iterative FLUKA and BIG2 Simulations	target, proton, experiment, collider	479
	F. Burkart, J. Blanco, D. Grenier, R. Schmidt, D. Wollmann CERN, Geneva, Switzerland N.A. Tahir GSI, Darmstadt, Germany
	In 2012, a novel experiment has been performed at the CERN HiRadMat facility to study the impact of a 440 GeV proton beam generated by the Super Proton Synchrotron (SPS), on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed. Iterative FLUKA and BIG2 simulations with the parameters of the actual experiment have been performed. In this paper the results of these simulations will be discussed and compared to the experimental measurements. Furthermore, the implication on the machine protection design for high intensity hadron accelerators as the current LHC and the future High Luminosity LHC will be addressed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME047
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME070	Investigation of a High Power, Low Impedance Pulse Forming Network based on Ceramic Capacitors	impedance, network, experiment, laser	529
	J. Gao, X.J. Ge, J. He, J. Liu NUDT, Changsha, People's Republic of China
	Solid state is one of the most important development directions for pulsed power technologies. For GW level pulse generators, switches and pulse forming units are difficult to implement with solid state components restricted by high power tolerance and high voltage insulation. Under certain pulse power, operation voltage is decided by impedance of the pulse forming unit, which means that pulse modulation with low impedance method should help improve insulation strength of a pulsed power system. Therefore, a high power, low impedance pulse forming network is developed based on solid components of ceramic capacitors in this research. It is designed that the impedance is 1.6 Ω, the pulse width is about 150 ns, and the output power is above 1 GW. Low impedance is accomplished via several pulse forming units connected in parallel with a circumferential structure, which could reduce the stray inductance due to good symmetrical characteristics. Key factors influencing pulse modulation process are investigated, stray parameters are examined by electromagnetic calculations and preliminary experiments are carried out, with results giving reasonable agreement with the theoretical cases.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME075	Cooling of the LHC Injection Kicker Magnet Ferrite Yoke: Measurements and Future Proposals	vacuum, kicker, injection, operation	544
	M.J. Barnes, S. Bouleghlimat, L. Ducimetière, M. Garlaschè, V. Gomes Namora, T. Kramer, R. Noulibos, Y. Sillanoli, Z.K. Sobiech, W.J.M. Weterings CERN, Geneva, Switzerland
	LHC operation with high intensity beam, stable for many hours, resulted in significant heating of the ferrite yoke of the LHC Injection Kicker Magnets. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. The beam screen, which screens the ferrite yoke from wakefields, has been upgraded to limit ferrite heating. In addition it is important to improve the cooling of the ferrite yoke: one method is to increase the internal emissivity of the cylindrical vacuum tank, in which the kicker magnet is installed. This paper describes a method developed for measuring the emissivity of the inside of the tanks, which has been benchmarked against measurements of the ferrite yoke temperature during heat treatment in an oven and transient thermal simulations. Conclusions are drawn regarding an ion bombardment technique evaluated for improving emissivity without degrading vacuum properties. In addition initial concepts for improved cooling are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME081	A Stripline Kicker Driver for the Next Generation Light Source	kicker, high-voltage, coupling, impedance	559
	F.M. Niell, N. Butler, M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: US Department of Energy, Award DE-SC00004255 Diversified Technologies, Inc. (DTI) assembled a prototype pulse generator capable of meeting the original specifications for the Next Generation Light Source (NGLS) fast deflector. The ultimate NGLS kicker driver must drive a 50 Ω terminated Transverse Electromagnetic (TEM) deflector blade at 10 kV, with flat-topped pulses and a sustained repetition rate of 100 kHz. Additional requirements of the specification include a 2 ns rise time (10 – 90%), a highly repeatable flattop with pulse width from 5 – 40 ns, and a fall time less than 1 μs (down to 10-4 of the peak value). The driver must also effectively absorb high-order mode signals emerging from the deflector itself. It is envisioned that a scintilla of deflection will be imparted by a symmetric pair of shaped parallel deflection blades, pulsed in opposition at 10 kV. Within the guide, each TEM wave produced by the two pulse generators traverses the guide synchronously with the selected (relativistic) charge packet. The DTI team has designed and demonstrated the key elements of a solid state kicker driver capable of meeting the NGLS requirements, with possible extension to a wide range of fast-pulse applications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME081
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI003	Positron Yield Optimization by Adjusting the Components Offset and Orientation	positron, target, electron, injection	576
	L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama KEK, Ibaraki, Japan S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI010	Laser Ablation Ion Source for the KEK Digital Accelerator	ion, laser, extraction, space-charge	598
	N. Munemoto Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan Y. Fuwa, S. Ikeda, M. Kumaki RIKEN, Saitama, Japan Y. Fuwa Kyoto ICR, Uji, Kyoto, Japan S. Ikeda, K. Takayama TIT, Yokohama, Japan M. Kumaki RISE, Tokyo, Japan M. Okamura BNL, Upton, Long Island, New York, USA S. Takano, K. Takayama KEK, Ibaraki, Japan K. Takayama Sokendai, Ibaraki, Japan
	KEK Digital Accelerator (DA) is a small scale induction synchrotron and operated at 10Hz and recently has succeeded to accelerate gaseous ions. There is a strong demand of fully striped carbon ions because the DA is regarded as the second generation of cancer therapy driver, which does not require an injector and electron stripper. We need a novel carbon ion source providing C⁶⁺ beams, which are directly injected into the DA and accelerated up to required energy. For this purpose, a laser ablation ion source(LAIS) is promising. To obtain high yield C⁶⁺ ions from ablation plasma, the laser irradiation condition has been evaluated and relationship between beam properties of charge spectrum, intensity, and temperature, and carbon target materials were examined. Two laser systems, long pulse (6 ns) and short pulse (170 ps), were employed to irradiate a graphite and amorphous carbon target. The current densities and profile of the generated plasmas in time were measured and charge state distributions were analyzed. In addition we will report a full design integrating this LAIS, the extraction system, the longitudinal chopper system, and the low energy beam transport line. T.Yoshimoto et al., presented in this conference ** N.Munemoto et al., Proceedings of ICIS2013, published in Rev. Sci. Inst.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI023	Simulation of the ELBE SRF Gun II	gun, emittance, SRF, laser	636
	P.N. Lu, A. Arnold, U. Lehnert, P. Murcek, J. Teichert, H. Vennekate, R. Xiang HZDR, Dresden, Germany
	Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191 By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI023
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI026	Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code	electron, laser, cathode, space-charge	645
	A. Fallahi, F.X. Kärtner CFEL, Hamburg, Germany K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang MIT, Cambridge, Massachusetts, USA
	Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg. We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI028	Different Countermeasures of Electron Amplification in the Photocathode Unit	cathode, electron, SRF, gun	652
	E.T. Tulu, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Arnold HZDR, Dresden, Germany
	Funding: Federal Ministry for Research and Education BMBF; Project: 05K2013-HOPE Superconducting radio frequency (SRF) structures may be subjected to electron multipacting (MP). The electrons emitted from one of the structure’s wall under certain conditions are accelerated by the RF field, thereby they may impact the wall again based on the field pattern in the structure. Accordingly the number of electrons increases exponentially caused by secondary electron emission. The latter depends on the secondary emission coefficient of the surface material and the electron trajectory in the device under study. This phenomenon limits the accelerating gradient in the cavity, moreover, it might cause an impair of RF components and distortion of the RF signal. Therefore, there should be an efficient countermeasure to suppress MP in order to boost the performance of the SRF gun. In this paper, three techniques of suppression of MP from the vicinity of the cathode, such as DC-bias, geometric modification and the microstructure of the cathode's surface, in the Rossendorf SRF gun are presented. The simulation has been done using CST Microwave Studio® and CST Particle Studio®*. Eventually, the efficient suppression method would be chosen for this particular case. H.Padamsee, J. Knobloch and T. Hays, 1998, Ch. 10. E. T. Tulu, A. Arnold and U. van Rienen, 16th International Conference on SRF, Paris, France, 2013. * CST AG, http://www.cst.com.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI030	Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun	cavity, gun, electron, vacuum	658
	T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai LEBRA, Funabashi, Japan M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida KEK, Ibaraki, Japan T.S. Shintomi Nihon University, Tokyo, Japan
	Funding: This research was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT). A cryocooled C-band photocathode RF gun operating at 20K is under design at Nihon University. The RF gun is of BNL-type 2.6-cell pillbox cavity with a resonant frequency of 5712 MHz. With high-purity Oxygen-free copper used as the cavity material, the quality factor of the cavity is expected to be approximately 60000 from theoretical prediction of the anomalous skin effect at low temperatures. Considering the cooling capacity, initial operation of the RF gun is assumed at a duty factor of 0.01%. The cavity elements designed for low-power test is in preparation for machining. The low-power test at room temperature is scheduled early spring in 2014 before assembled at KEK by means of diffusion bonding technique. Since it is intended for the basic understanding and measurements of low temperature RF properties, the cavity is not equipped with structures for the photocathode assembling or the RF input coupler. The cavity design and the results of RF properties measured at room temperature before diffusion bonding will be reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI039	Ultra-short Electron Bunch Generation using Energy-chirping Cell Attached RF Electron Gun	gun, electron, cavity, radiation	685
	K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio Waseda University, Tokyo, Japan R. Kuroda AIST, Tsukuba, Ibaraki, Japan T. Takatomi, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690 We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-RF-Gun) for generating ultra-short electron bunches. ECC-RF-Gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3THz. It is clear that the bunch length was short enough to generate 0.3THz, which corresponds to less than 500fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-RF-Gun, the recent results of bunch length measurement and future prospective will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI040	Design and Analysis of an Electron Beam in an Electron Gun for X-Ray Radiotherapy	electron, gun, cathode, emittance	688
	J.C. Lee, J.-S. Chai, M. Ghergherehchi, H.S. Kim, Y.S. Lee, S. Shin, Y.H. Yeon SKKU, Suwon, Republic of Korea B.N. Lee KAERI, Dae-jeon, Republic of Korea
	Funding: This work was supported by (IT R&D program of MSIP/KEIT [10043897] and MOTIE [13-DU-EE-12]) in KOREA. Electron linear accelerators are used as x-ray generators for diagnosing the human body. In this paper conceptual design of electron beam for compact electron gun was calculated by using EGN2w and CST-Particle Studio codes. The structure of the electron gun was used for Pierce and diode type and the specification of electron beam was selected as 500 cGy/min. Specifications of designed electron gun were focused on current, beam size and normalized emittance. Optimized beam current, diameter and normalized emittance are 226.88 mA, 0.689 mm (Full width) and 1.03π mm• mrad, respectively by using two simulation codes. Accuracy of simulation was verified by comparison of emitted beam current which has error of 0.74%. * Subhash C. Sharma et al., Journal of applied clinical medical physics, 8, 3 (2007) 119-125. * Yuichiro Kamino et al., Med. Phys. 34 (2007) 1797-1808.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI051	Measurements of the Longitudinal Energy Distribution of Low Energy Electrons	cathode, electron, laser, experiment	720
	L.J. Devlin, O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom L.J. Devlin, O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1 The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI051
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI069	Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs	radiation, plasma, laser, GPU	761
	R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T.E. Cowan HZDR, Dresden, Germany
	Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI069
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI077	Hi-Lumi LHC Collimation Studies with MERLIN Code	collimation, optics, scattering, proton	784
	M. Serluca, R. Appleby, J. Molson UMAN, Manchester, United Kingdom R.J. Barlow, H. Rafique, A.M. Toader University of Huddersfield, Huddersfield, United Kingdom
	The collimation system is key to the successful operation of the LHC. Measurements and simulations of the previous run at 4 TeV have shown that the system is ready for the next step, running at 7 TeV, but at the same time some sensitive cleaning locations have been identified. In particular the dispersion suppressors downstream of the betatron cleaning region in IR7 are sensitive to single diffractive scattered protons from the collimator jaws. These particles can lead to magnet quenching. The MERLIN C++ library has been developed to exploit the functionality of an object oriented code, with improved collective effects and scattering routines. New single diffractive and elastic scattering routines, based on a fit of existing experimental data with the Regge theory of soft interactions of high energy scattering, is implemented in MERLIN. In this paper we present the impact of the new single diffractive scattering physics on the cleaning inefficiency of the LHC collimation system for the Achromatic Telescope Squeezing (ATS) PreSqueeze optics scheme, for the HL-LHC project. The results are compared with the same loss map calculated using a SixTrack+K2 like scattering routine.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI077
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI081	Beam Simulation for Improved Operation of Cyclotron NIRS-930	cyclotron, injection, experiment, extraction	797
	M. Nakao, S. Hojo, K. Katagiri, A. Noda, K. Noda, A. Sugiura NIRS, Chiba-shi, Japan A. Goto Yamagata University, Yamagata, Japan T. Honma, A.K. Komiyama, T. Okada, Y. Takahashi AEC, Chiba, Japan V.L. Smirnov, S.B. Vorozhtsov JINR, Dubna, Moscow Region, Russia
	Beam simulation using SNOP* code has been performed for the cyclotron NIRS-930 at NIRS in order to study beam dynamics in a cyclotron and to improve beam intensity. Each electric or magnetic field (main coil, trim coils, harmonic coils, magnetic channel, gradient corrector, grazer lens, dee electrode, inflector) were calculated by OPERA-3d, and simulated injection, acceleration, and extraction. The simulation of proton with 30 MeV extracting energy with harmonic 1 was already performed and well simulated RF phase and extraction efficiency*. Then we tried to apply SNOP to 18 MeV protons with harmonic 2. We first formed isochronous magnetic field with main and trim coils for simulating single particle. Next we optimized electric deflector and magnetic channel in order to maximize extracted particles simulating the bunch of particles. Beam loss of the simulation was compared to the experiment. And then we are optimizing position and rotation of inflector and position of puller to improve injection. We intend to apply optimized simulation parameter to actual cyclotron operation to improve beam intensity and quality. V.L. Smirnov, S.B. Vorozhtsov, Proc. of RUPAC2012 TUPPB008 325 (2012) ** V.L. Smirnov et al., Proc. of IPAC2012 292 (2012)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI081
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI085	IMALION – Creation and Low Energy Transportation of a Milliampere Metal Ion Beam	ion, ion-source, ECR, plasma	809
	A. Silze, M. Kreller, G.H. Zschornack DREEBIT GmbH, Dresden, Germany U. Hartung, T. Kopte, T. Weichsel Fraunhofer FEP, Dresden, Germany
	Funding: This work is supported by the European Regional Development Fund (ERDF) and the Freistaat Sachsen (project no. 100074113 and 100074115). IMALION – which stands for IMplantation of ALuminum IONs – is a facility originally designed for applications in photovoltaics and other branches in semiconductor industry. The idea was to create and guide a milliampere beam of low charged metal ions so that targets with a width of 20 cm and more can be irradiated homogeneously with minimal differences in intensity and entrance angle of the incoming beam over the entire surface. In this poster, we outline the solutions which had to be found during the realization of the project. This concerns the production of a milliampere metal ion current in a newly designed electron cyclotron resonance (ECR) ion source combined with an internal sputter magnetron device. Stable operation of the sputter magnetron under ECR magnetic mirror conditions has been proven by optical spectroscopy and Langmuir probe measurements. Furthermore, electrostatic and magnetic beamline elements developed for precision guiding of a low energy but high intensity beam as well as high intensity ion beam diagnostics are presented and ion beam transportation simulations are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI085
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI091	Resonant Slow Extraction in Synchrotrons by Using Anti-symmetric Sextupole Fields	sextupole, resonance, extraction, synchrotron	827
	Y. Zou, J.Y. Tang IHEP, Beijing, People's Republic of China
	This paper proposes a novel method for non-resonant slow extraction by using special anti-symmetric sextupole field in synchrotrons. The method has the potential in applications asking for stable slow extraction and in the halo collimation of very large machine such as LHC. Our studies show that the slow extraction by using anti-symmetric sextupole field has some advantages compared to the normal sextupole field which is the normal extraction method. One of them is that it can work at almost arbitrary tune, so that it can avoid the problem of the intensity variation caused by the ripples of magnet supplies. Studies by Hamiltonian theory and simulations which meet well show that the stable region only depends on the anti-symmetric sextupole field strength and the particles outside will be driven out in two directions which are similar to the second-order resonant extraction but with spiral steps as in the third-order resonance extraction. The beam can be extracted with a very stable intensity by gradually increasing the field strength. The multi-particle simulations by a self-made program have been carried out with a proton lattice designed for proton therapy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI091
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI097	Feasibility Studies for the Extraction of both LHC Beams from CERN SPS using a Common Kicker	extraction, kicker, septum, impedance	842
	F.M. Velotti, W. Bartmann, C. Bracco, E. Carlier, K. Cornelis, B. Goddard, V. Kain, M. Meddahi CERN, Geneva, Switzerland
	The CERN Super Proton Synchrotron has to fulfil the demanding intensity specifications for the High Luminosity LHC (HL-LHC) era, with a doubling of the presently achieved operational beam intensity. One of the main problems to be addressed is given by impedance-driven beam instabilities. About 40 % of the total measured SPS impedance is due to the kickers, of which the extraction kickers in two of the SPS straight sections are the largest systems. A potential upgrade is explored which would strongly reduce the number of extraction kickers required in the SPS, by performing non-local extraction. In this scenario LHC Beam 1 would be kicked by the extraction kicker in SPS Long Straight Section 4 (LSS4), normally only used for Beam 2, to be extracted in LSS6. The concept and the expected performance of such a scheme are presented along with detailed simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI097
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI098	Design Studies of the Upgraded Collimation System in the SPS-to-LHC Transfer Lines	collimation, luminosity, injection, optics	845
	A. Mereghetti, C. Bracco, F. Cerutti, B. Goddard, J. Hrivnak, V. Kain, F.L. Maciariello, M. Meddahi, G.E. Steele CERN, Geneva, Switzerland R. Appleby UMAN, Manchester, United Kingdom
	In the framework of the LHC Injectors Upgrade (LIU) Project, the collimators in the SPS-to-LHC transfer lines are presently under re-design, in order to cope with the unprecedented beam intensities and emittances required by the High Luminosity LHC (HL-LHC). Factors ruling the design phase are the robustness of the jaws on one side and, on the other side, the proton absorption and the emittance blow-up, essential for an effective protection of the equipment in the LHC injection regions and the LHC machine. In view of the new design, based on the one of the currently installed TCDI collimators and past investigations, the FLUKA Monte Carlo code is used to address these two factors. The present studies are intended to give essential feedback to the identification of viable solutions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI098
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI104	Measurement of Beam Ioniziation Loss in SIS18	ion, vacuum, injection, extraction	864
	L.H.J. Bozyk, P.J. Spiller GSI, Darmstadt, Germany
	In the heavy ion synchrotron SIS18 at GSI an ion catcher system has been installed to provide low desorption surfaces for ionization beam loss to reduce dynamic vacuum effects. Medium charge state heavy ions can change their charge state in collission with residual gas molecules. Those ions are cought by the ion catcher system. The ion catcher blocks are mounted electrically insulated, such that it is possible, to directly measure the electrical current, induced by the incident ions. Changes in vacuum density during the acceleration cycle and also the energy dependent decrease of the cross sections for electron loss and electron capture can be measured by this system. Different ion catcher currents, measured during the operation with U²⁸⁺, and their interpretation are presented. The measurement of ionization beam loss is a valuable tool to benchmark the dynamic vacuum simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI104
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI106	Simulation Study of Beam Halo Collimation in the Heavy-ion Synchrotron SIS 100	ion, collimation, heavy-ion, injection	870
	I.A. Prokhorov TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim, I. Strašík GSI, Darmstadt, Germany
	Funding: Work is supported by German Federal Ministry of Education and Research (BMBF) contract no. 05P12RDRBM The FAIR synchrotron SIS-100 will be operated with high-intensity proton and heavy-ion beams. The collimation system should prevent beam loss induced degradation of the vacuum, activation of the accelerator structure and magnet quenches. A conventional two-stage betatron collimation system is considered for the operation with protons and fully-stripped ions. Particle tracking and ion-collimator interaction simulations of the collimation system were performed. The angular and momentum distributions of the scattered halo particles were described using analytical models and numerical tools like ATIMA and FLUKA. MADX was used for the multi-pass tracking simulations. The results obtained for the collimation cleaning efficiency as a function of the ion species and beam energy together with the detailed beam losses distributions along the ring circumference are presented. This work highlights the main aspects of the collimation of fully-stripped ion beams in the intermediate energy range using conventional two-stage systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI106
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI107	The Mitigation System of the Large Angle Foil Scattering Beam Loss caused by the Multi-turn Charge-exchange Injection	injection, scattering, insertion, operation	873
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan H. Harada, H. Hotchi, M. Kinsho, K. Yamamoto JAEA/J-PARC, Tokai-mura, Japan
	Funding: Research Fellow of Japan Society for the Promotion of Science In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and the circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we developed a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we focused on the relative angle of collimator block from scattering particles. We developed the beam based angler regulation method by the simulation and achieved the sufficient mitigation of the loss at 181 MeV injection energy. Since the injection energy will be upgraded to 400 MeV in this year, we will start to estimate again the collimator performance by the upgraded simulation set. We present this system as one of the mitigation methods of the large angle foil scattering beam loss caused by the multi-turn charge-exchange injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI107
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI110	Final Layout and Expected Cleaning for the First Crystal-assisted Collimation Test at the LHC	collimation, proton, injection, ion	882
	D. Mirarchi, S. Montesano, S. Redaelli, W. Scandale CERN, Geneva, Switzerland F. Galluccio INFN-Napoli, Napoli, Italy A.M. Taratin JINR, Dubna, Moscow Region, Russia
	The installation in the CERN Large Hadron Collider (LHC) of two crystals in the horizontal and vertical planes was accomplished during the present LHC long shutdown (LS1) for crystal collimation studies. An appropriate layout was designed to demonstrate the principle feasibility of crystal collimation at the LHC. Extensive simulation campaigns were made to evaluate different crystal positions and parameters, in order to ensure that the main goals of these first feasibility tests in the LHC are within reach. In this paper, the final layout is presented. An overview of the considerations behind the design choices and the crystal parameters is given, and the expected performance of the system is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI110
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI111	Improvements of the Crystal Routine for Collimation Studies	proton, collimation, scattering, extraction	886
	D. Mirarchi, S. Redaelli, W. Scandale CERN, Geneva, Switzerland A.M. Taratin JINR, Dubna, Moscow Region, Russia I.A. Yazynin IHEP, Moscow Region, Russia
	A routine has been implemented to simulate interactions of protons with bent crystals in the collimation version of \texttt{SixTrack}. This routine is optimized in view of producing high-statistics tracking simulations of collimation cleaning assisted by bent crystals. Fine tuning and comparisons with experimental data of coherent effects which a particle can experience in a bent crystal have been carried out. The data taken with 400 GeV beams at the CERN-SPS North Area in the framework of the UA9 experiment are used to benchmark the routine. Further checks on low probability interactions have been made, leading to significant improvements in the description of interactions with crystals. Comparisons with other simulations tools are used to increase our confidence in the scaling to higher energies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI111
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI114	Numerical Estimation of the Equivalent Dose Rate after the Irradiation of a Tungsten Collimator by a Low Energy Proton Beam	proton, cyclotron, radiation, operation	890
	V. Talanov, D.C. Kiselev, M. Wohlmuther PSI, Villigen PSI, Switzerland
	The issue of activation of a Tungsten collimator by protons is considered for the incident energy of 12.2 MeV. Two different simulation approaches using the Monte Carlo programs MCNPX and FLUKA are applied to estimate the equivalent remanent dose rate after the irradiation of the collimator. The results of the numerical simulation are then compared to the measured dose levels of the collimator of the COMET cyclotron at Paul Scherrer Institut (PSI).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI114
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI115	Activation Models of the ISIS Collectors	synchrotron, controls, operation, scattering	893
	H. V. Smith, D.J. Adams, B. Jones, C.M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS facility at the Rutherford Appleton Laboratory is a pulsed neutron and muon source, for materials and life science research. The 163 m circumference, 800 MeV, 50 Hz rapid cycling synchrotron accelerates up to 3·10¹³ protons per pulse. The maximum operating intensity of the synchrotron is limited by loss during acceleration, mainly due to the non-adiabatic longitudinal trapping process between 0 and 3 ms, corresponding to energies between 70 and 200 MeV. In order to minimise global machine activation and prevent component damage a beam collimation, or collector, system is installed in a five metre drift section in super-period one, to localise loss to this region. This paper summarises new results from modelling of the beam collectors using the FLUKA code [1, 2]. Understanding the current performance of the collectors is important for high intensity beam optimisation and may influence future injection upgrade plans. Residual dose rates are compared to film badge measurements, predicted energy deposition results are compared to the measured heat load on the collector cooling systems and an assessment is made of the distribution of particles exiting the collector straight.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI115
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB02	Design Study of the SuperKEKB Interaction Region Optics	sextupole, octupole, quadrupole, dynamic-aperture	950
	H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi, K. Oide KEK, Ibaraki, Japan
	SuperKEKB is an upgrade project of KEKB e⁺e⁻ ring collider and is aimed to open up a new luminosity frontier. The target peak luminosity is 8x10³⁵ cm^-2 s^-1. In order to achieve this target, a nano-beam scheme is adopted, in which colliding beams are squeezed to nano-scale sizes in the vertical direction at the interaction point (IP). The interaction region (IR) is an essential part of the SuperKEKB lattice design since the large chromaticity originated in the final focusing system (QCS) and strong lattice nonlinear forces make the particle motion unstable. An optics with detailed hardware specifications has been designed to optimize a performance of the beam dynamics. Design studies of IR taking into account a possible QCS imperfection are reported in this paper.
	Slides TUOAB02 [9.899 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAB02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB03	Nonlinear Optics for Suppression of Halo Formation in Space Charge Dominated Beams	focusing, quadrupole, space-charge, emittance	953
	Y.K. Batygin, A. Scheinker LANL, Los Alamos, New Mexico, USA C. Li IMP, Lanzhou, People's Republic of China
	Traditional accelerator designs utilize linear focusing elements (quadrupoles, solenoids) to provide stable particle motion. High – intensity rms - matched non - uniform beams are intrinsically mismatched with linear focusing structure. It results in space charge induced beam emittance growth and halo formation, which can be suppressed in a quadrupole channel with higher-order multipole field components. In this paper, overview of FODO quadrupole channels with arbitrary multipoles is given. Effective averaged potential is presented for the structure with periodic combination of multipole lenses and quadrupoles. Density of matched beam avoiding emittance growth and halo formation is derived. Performed analysis allows matching of realistic beam with the internal structure of the focusing field. Beam dynamics studies with suppressed halo are presented and discussed.
	Slides TUOAB03 [3.404 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAB03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO002	Fringe Fields Modeling for the High Luminosity LHC Large Aperture Quadrupoles	quadrupole, luminosity, multipole, controls	993
	B. Dalena, A. Chancé, O. Gabouev CEA/IRFU, Gif-sur-Yvette, France R. Appleby, D.R. Brett UMAN, Manchester, United Kingdom R. De Maria, M. Giovannozzi CERN, Geneva, Switzerland J. Payet CEA/DSM/IRFU, France
	Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan. The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Analytical evaluations of detuning with amplitude and chromatic effects show that the effect is small, but not negligible. Therefore, the effect on long-term beam dynamics is evaluated via tracking simulations. Different tracking models are compared in order to provide a numerical estimate of this effect due to the proposed inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO002
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO003	Fast Crab Cavity Failures in HL-LHC	operation, optics, luminosity, synchrotron	997
	B. Yee-Rendón, R. Lopez-Fernandez CINVESTAV, Mexico City, Mexico J. Barranco García EPFL, Lausanne, Switzerland R. Calaga, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland
	Crab cavities (CCs) are a key ingredient of the High-Luminosity Large Hadron Collider (HL-LHC) to ensure head on collisions at the main experiments (ATLAS and CMS) and fully profit from the smaller β* provided by the ATS optics. At KEKB, CCs have exhibited abrupt changes of phase and voltage during a time period of few LHC turns and considering the large energy stored in the HL-LHC beam, CC failures represent a serious risk to the LHC machine protection. In this paper, we discuss the effect of CC voltage or phase changes on a time interval similar to, or longer than, necessary to dump the beam. The simulations assume a realistic steady-state distribution to assess the beam losses for the HL-LHC. Additionally, some strategies are studied to mitigate the damage caused by the failures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO003

Paper

Title

Other Keywords

Page

MOZA01

Ultralow Emittance Beam Production based on Doppler Laser Cooling and Coupling Resonance

laser, ion, coupling, solenoid

28

A. Noda, M. Nakao
NIRS, Chiba-shi, Japan
M. Grieser
MPI-K, Heidelberg, Germany
Z.Q. He
FRIB, East Lansing, Michigan, USA
Z.Q. He
TUB, Beijing, People's Republic of China
K. Jimbo
Kyoto University, Kyoto, Japan
H. Okamoto, K. Osaki
HU/AdSM, Higashi-Hiroshima, Japan
A.V. Smirnov
JINR, Dubna, Moscow Region, Russia
H. Souda
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
Y. Yuri
JAEA/TARRI, Gunma-ken, Japan

Funding: Work supported by Advanced Compact Accelerator Development project by MEXT of Japan. It is also supported by GCOE project at Kyoto University, “The next generation of Physics-Spun from Universality"
Doppler laser cooling has been applied to low-energy (40 keV) Mg ions together with the resonant coupling method* at the S-LSR at ICR, Kyoto University,. The S-LSR storage ring has a high super periodicity of 6, which is preferable from the beam dynamical point of view. At S-LSR one dimensional ordering of proton beam was already realized for the first time**. Active three dimensional laser cooling has been experimentally demonstrated for ions with un-negligible velocity (v/c=0.0019, where c is the light velocity) for the first time. Utilizing the above mentioned characteristics of S-LSR, an approach to realize ultralow emittances has been pursuit. To suppress heating effects, due to intra-beam scattering, the circulating ion beam intensity was reduced by scraping and beam emittances of 1.3·10^-11 pi m·rad and 8.5·10^-12 pi m·rad (normalized) have been realized for the horizontal and vertical directions, respectively with the 40 keV Mg ion beam at a beam intensity of ~10⁴, which is the lowest emittance ever attained by laser cooling. From MD computer simulations, it is predicted that reduction of the ion number to about 10³ is needed to realize a crystalline string.
* H. Okamoto, A.M. Sessler, D. Moehl, Phys. Rev. Lett. 72, 397 (1994).
** T. Shirai et. al., Phys. Rev. Lett. 98, 204801 (2007).

Slides MOZA01 [13.336 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOZA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOCB01

Beam-induced Quench Tests of LHC Magnets

quadrupole, collimation, experiment, beam-losses

52

M. Sapinski, B. Auchmann, T. Bär, W. Bartmann, M. Bednarek, S. Bozyigit, C. Bracco, R. Bruce, F. Cerutti, V. Chetvertkova, K. Dahlerup-Petersen, B. Dehning, E. Effinger, J. Emery, A. Guerrero, E.B. Holzer, W. Höfle, A. Lechner, A. Priebe, S. Redaelli, B. Salvachua, R. Schmidt, N.V. Shetty, A.P. Siemko, E. Skordis, M. Solfaroli Camillocci, J. Steckert, J.A. Uythoven, D. Valuch, A.P. Verweij, J. Wenninger, D. Wollmann, M. Zerlauth, E.N. del Busto
CERN, Geneva, Switzerland

At the end of the LHC Run1 a 48-hour quench-test campaign took place to investigate the quench levels of superconducting magnets for loss durations from nanoseconds to tens of seconds. The longitudinal losses produced extended from one meter to hundreds of meters and the number of lost protons varied from 10⁸ to 10¹³. The results of these and other, previously conducted quench experiments, allow the quench levels of several types of LHC magnets under various loss conditions to be assessed. The quench levels are expected to limit LHC performance in the case of steady-state losses in the interaction regions and also in the case of fast losses initiated by dust particles all around the ring. It is therefore required to accurately adjust beam loss abort thresholds in order to maximize the operation time. A detailed discussion of these quench test results and a proposal for additional tests after the LHC restart is presented.

Slides MOOCB01 [2.737 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCB01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO002

The Momentum Distribution of the Decelerated Drive Beam in CLIC and in the Two-beam Test Stand at CTF3

emittance, operation, distributed, controls

62

Ch. Borgmann, M. Jacewicz, J. Ögren, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

We present analytical calculations of the momentum spectrum of the drive beam in CLIC and the CLIC Test Facility CTF3 after part of its kinetic energy is converted to microwaves for the acceleration of the main beam. The resulting expressions are used to determine parameters of the power conversion process in the Power Extraction Structure (PETS) installed in the Two-beam Test Stand in CTF3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO007

GPU-Accelerated Long-Term Simulations of Beam-Beam Effects in Colliders

GPU, luminosity, collider, electron

77

B. Terzić, F. Lin, V.S. Morozov, Y. Roblin, H. Zhang
JLab, Newport News, Virginia, USA
M. Aturban, D. Ranjan, M. Zubair
ODU CS, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We present an update on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order particle tracking (including a symplectic option) for beam transport and the generalized Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, previously computationally prohibitive long-term simulations become tractable. The new code will be used to model the proposed Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO012

Simulating Fast Beam-Ion Instability Studies in FFAG-Based ERHIc Rings

electron, ion, linac, lattice

83

G. Wang, V. Litvinenko, Y. Luo
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In an electron accelerator, ions generated from the residual gas by the circulating electrons act back to the trailing electrons. Under unfavorable conditions this feed-back can cause unstable motion of the electron bunches, the process known as the fast beam ion instability. Current eRHIC design has two FFAG rings transporting 21 electron beams at 11 different energies. In this study, we use numerical simulation to investigate the fast ion instability in this complicated system, compare the simulation results with theory and discuss possible measures to mitigate the instability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO019

Energy Deposition and Quench Level Calculations for Millisecond and Steady-state Quench Tests of LHC Arc Quadrupoles at 4 TeV

proton, beam-losses, quadrupole, operation

105

N.V. Shetty, B. Auchmann, V. Chetvertkova, A. Lechner, A. Priebe, M. Sapinski, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

In 2013, beam-induced quench tests with 4 TeV protons were performed to probe the quench level of LHC arc quadrupole magnets at timescales corresponding to millisecond beam losses and steady-state losses. As the energy deposition in magnet coils cannot be measured directly, this study presents corresponding FLUKA simulations as well as estimates of quench levels derived with the QP3 code. Furthermore, beam loss monitor (BLM) signals were simulated and benchmarked against the measurements. Simulated and measured BLM signals are generally found to agree within 30 percent.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO020

FLUKA Simulation of Particle Fluences to ALICE due to LHC Injection Kicker Failures

injection, kicker, high-voltage, detector

109

N.V. Shetty, C. Bracco, A. Di Mauro, A. Lechner, E. Leogrande, J.A. Uythoven
CERN, Geneva, Switzerland

The counter-rotating beams of the LHC are injected in insertion regions which also accommodate the ALICE and LHCb experiments. An assembly of beam absorbers ensures the protection of machine elements in case of injection kicker failures, which can affect either the injected or the stored beam. In the first years of LHC operation, secondary particle showers due to beam impact on the injection beam stopper caused damage to the MOS injectors of the ALICE silicon drift detector as well as high-voltage trips in other ALICE subdetectors. In this study, we present FLUKA simulations of particle fluences to the ALICE cavern for injection failures encountered during operation. Two different cases are reported, one where the miskicked beam is fully intercepted and one where the beam grazes the beam stopper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO021

Power Deposition in LHC Magnets With and Without Dispersion Suppressor Collimators Downstream of the Betatron Cleaning Insertion

proton, dipole, operation, collimation

112

A. Lechner, B. Auchmann, R. Bruce, F. Cerutti, P.P. Granieri, A. Marsili, S. Redaelli, N.V. Shetty, E. Skordis, G.E. Steele, A.P. Verweij
CERN, Geneva, Switzerland

The power deposited in dispersion suppressor (DS) magnets downstream of the LHC betatron cleaning insertion is governed by off-momentum protons which predominantly originate from single-diffractive interactions in primary collimators. With higher beam energy and intensities anticipated in future operation, these clustered proton losses could possibly induce magnet quenches during periods of short beam lifetime. In this paper, we present FLUKA simulations for nominal 7 TeV operation, comparing the existing layout with alternative layouts where selected DS dipoles are substituted by pairs of shorter higher-field magnets and a collimator. Power densities predicted for different collimator settings are compared against present estimates of quench limits. Further, the expected reduction factor due to DS collimators is evaluated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO027

Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings

impedance, coupling, kicker, damping

125

C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
M.J. Barnes, H.A. Day
CERN, Geneva, Switzerland
F. Toral
CIEMAT, Madrid, Spain

The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO029

Feed Forward Orbit Correction in the CLIC Ring to Main LINAC Transfer Lines

emittance, kicker, extraction, collimation

131

R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven
CERN, Geneva, Switzerland

The emittance growth in the betatron collimation system of the 27 km long transfer lines between the CLIC damping rings and the main LINAC depends strongly on the transverse orbit jitter. The resulting stability requirements of the damping ring extraction elements seem extremely difficult to achieve. Position and angle feed forward systems in these long transfer lines bring the specified parameters of the extraction elements within reach. The designs of the optics and feed forward hardware are presented together with tracking simulations of the systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO033

Design and Feasibility Study of a Transverse Halo Collimation System for ATF2

wakefield, collimation, background, betatron

145

N. Fuster-Martínez
Valencia University, Atomic Molecular and Nuclear Physics Department, Valencia, Spain
P. Bambade, S. Liu, S. Wallon
LAL, Orsay, France
A. Faus-Golfe, J. Resta-López
IFIC, Valencia, Spain
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work supported by FPA2010-21456-C02-01 and by i-link 0704
This paper presents the design of a halo collimation system for the ATF2 beamline. The main objective is the reduction of background noise that limits the performance of key diagnostic devices around the final focal point (IP), especially the Shintake Monitor (IPBSM) used for measuring the nanometer level vertical beam sizes and the future Diamond Sensor (DS) for measuring the beam halo. Beam tracking simulations have been performed to optimize the position and characteristics of the halo collimation devices. Furthermore the collimator wakefield-induced effect is being studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO035

Update on Nonlinear Collimation Schemes for the LHC

collimation, sextupole, optics, betatron

151

J. Resta-López
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Faus-Golfe, L. Lari, J. Resta-López
IFIC, Valencia, Spain

Funding: FP7 HL-LHC Grant Agreement 284404
In this paper we review the status of the studies on nonlinear collimation schemes for the LHC. Concretely we describe the design of a nonlinear optics for betatron cleaning in IR7. The aim is to investigate alternative nonlinear collimation systems to reduce the collimator-induced impedance that may limit the beam intensity towards the LHC luminosity upgrade. The performance of the LHC nonlinear collimation system is studied by means of tracking simulations and compared with the present LHC system. Furthermore, the advantages and possible limitations of such nonlinear collimation scheme are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO036

Beam Life Time and Stability Studies for ELENA

electron, antiproton, emittance, vacuum

154

J. Resta-López, O. Karamyshev, D. Newton, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, D. Newton, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
IFIC, Valencia, Spain

Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. At such low energies it is very important to carefully take contributions from electron cooling and heating effects (e.g. on the residual gas) into account. Detailed investigations into the ion kinetics under consideration of effects from electron cooling and scattering on the residual gas have been carried out using the BETACOOL code. In this contribution a consistent explanation of the different physical effects acting on the beam in ELENA is given. Beam lifetime, equilibrium momentum spread and emittance are all estimated based on numerical simulations. Finally, optimum machine settings are presented as a result of optimization studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO037

Collimator Fast Failure Losses for Various HL-LHC Configurations

optics, collimation, kicker, luminosity

157

L. Lari, R. Bruce, S. Redaelli
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The upgrade of the Large Hadron Collider (LHC), in terms of beam intensity and energy, implies an increasing risk of severe damage in particular in case of fast failures losses. For this reason, efforts were put in developing simulation tools to allow studies of asynchronous dump accident, including realistic failure cases for collimator settings and machine parameters like orbit and optics. The scope of these studies is to understand realistic beam loads in different collimators, in order to improve the actual LHC collimator system design, to provide feedbacks on optic design and to evaluate different mitigation actions. Simulations were set up with a modified SixTrack collimation routine able to simulate erroneous firing of a single dump kicker or the simultaneous malfunction of all the 15 kickers. In such a context, results are evaluated from the whole LHC collimation system point of view.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO039

Integrated Simulation Tools for Collimation Cleaning in HL-LHC

collimation, scattering, proton, lattice

160

R. Bruce, C. Bracco, F. Cerutti, A. Ferrari, A. Lechner, A. Marsili, A. Mereghetti, D. Mirarchi, P.G. Ortega, D. Pastor Sinuela, S. Redaelli, A. Rossi, B. Salvachua, V. Vlachoudis
CERN, Geneva, Switzerland
R. Appleby, J. Molson, M. Serluca
UMAN, Manchester, United Kingdom
R.W. Aßmann
DESY, Hamburg, Germany
R.J. Barlow, H. Rafique, A.M. Toader
University of Huddersfield, Huddersfield, United Kingdom
S.M. Gibson, L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
L. Lari
IFIC, Valencia, Spain
C. Tambasco
University of Rome La Sapienza, Rome, Italy

The Large Hadron Collider is designed to accommodate an unprecedented stored beam energy of 362~MJ in the nominal configuration and about the double in the high-luminosity upgrade HL-LHC that is presently under study. This requires an efficient collimation system to protect the superconducting magnets from quenches. During the design, it is therefore very important to accurately predict the expected beam loss distributions and cleaning efficiency. For this purpose, there are several ongoing efforts in improving the existing simulation tools or developing new ones. This paper gives a brief overview and status of the different available codes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO040

Collimation Cleaning for HL-LHC Optics Scenarios with Error Models

collimation, alignment, optics, dipole

163

A. Marsili, R. Bruce, S. Redaelli
CERN, Geneva, Switzerland

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The upgrade of the LHC collimation system in view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) foresees, amongst other scenarios, local collimation in the dispersion suppressors (DS) of IR7. Layouts have been worked out which rely on using stronger and short bending dipoles to free space for a collimator in the cold DS. In this paper, the effectiveness of the proposed layouts is studied with different imperfection models such as collimator alignment, jaw tilt and surface errors, optics errors and aperture imperfections. The effect of local DS collimation on the global losses around the ring is also addressed for different optics configurations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO041

Multi-turn Tracking of Collision Products at the LHC

proton, luminosity, betatron, optics

166

A. Marsili, R. Bruce, F. Cerutti, L.S. Esposito, S. Redaelli
CERN, Geneva, Switzerland

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The luminosity expected at the interaction points in LHC at 7 TeV will be unprecedented, up to 1034 cm−2 s−1 . Part of the debris produced by the collisions is lost locally im- mediately downstream the Interaction Point (IP), in the matching section and dispersion suppressor. In this paper, the dynamics of collision debris protons is discussed. First, the loss distributions close to the collision points, simulated with two codes – SixTrack and FLUKA – are compared for different layout configurations. Then, SixTrack is used to simulate the fraction of protons that have undergone inelastic interactions with smaller energy and and betatron offsets, which could travel for several turns around the ring and might be lost in other collimation insertions. A preliminary comparison is made between the resulting loss distribution and measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO042

Cleaning Performance with 11T Dipoles and Local Dispersion Suppressor Collimation at the LHC

dipole, optics, collimation, proton

170

R. Bruce, A. Marsili, S. Redaelli
CERN, Geneva, Switzerland

The limiting location of the present LHC machine in terms of losses on cold magnets are the dispersion suppressors downstream of the betatron collimation insertion (IR7). These losses are dominated by off-energy protons that have by-passed the upstream secondary collimation system but are lost where the dispersion starts to rise. A solution under consideration for intercepting these losses is the addition of new collimators in the dispersive area. This paper discusses first a proposition for the new layout in the DS, where space is made for the new collimators by replacing an existing dipole by shorter and stronger magnets. Furthermore, simulations with SixTrack are presented, which quantify the gain in cleaning from the new collimators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO043

Handling 1 MW Losses with the LHC Collimation System

collimation, beam-losses, betatron, proton

174

B. Salvachua, R. Bruce, F. Carra, M. Cauchi, E.B. Holzer, W. Höfle, D. Jacquet, L. Lari, D. Mirarchi, E. Nebot Del Busto, S. Redaelli, A. Rossi, M. Sapinski, R. Schmidt, G. Valentino, D. Valuch, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
M. Cauchi
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain

Funding: Research supported by EU FP7 HiLumi LHC (Grant agree. 284404)
The LHC superconducting magnets in the dispersion suppressor of IR7 are the most exposed to beam losses leaking from the betatron collimation system and represent the main limitation for the halo cleaning. In 2013, quench tests were performed at 4 TeV to improve the quench limit estimates, which determine the maximum allowed beam loss rate for a given collimation cleaning. The main goal of the collimation quench test was to try to quench the magnets by increasing losses at the collimators. Losses of up to 1 MW over a few seconds were generated by blowing up the beam, achieving total losses of about 5.8 MJ. These controlled losses exceeded by a factor 2 the collimation design value, and the magnets did not quench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO045

Beam Delivery Simulation: BDSIM - Development & Optimisation

lattice, collider, background, detector

182

L.J. Nevay, S.T. Boogert, H. Garcia, S.M. Gibson, R. Kwee-Hinzmann, J. Snuverink
JAI, Egham, Surrey, United Kingdom
L.C. Deacon
UCL, London, United Kingdom

Funding: Research supported by FP7 HiLumi LHC - grant agreement 284404.
Beam Delivery Simulation (BDSIM) is a Geant4 and C++ based particle tracking code that seamlessly tracks particles through accelerators and detectors, including the full range of particle interaction physics processes from Geant4. BDSIM has been successfully used to model beam loss and background conditions for many current and future linear accelerators such as the Accelerator Test Facility 2 (ATF2) and the International Linear Collider (ILC). Current developments extend its application for use with storage rings, in particular for the Large Hadron Collider (LHC) and the High Luminosity upgrade project (HL-LHC). This paper presents the latest results from using BDSIM to model the LHC as well as the developments underway to improve performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO046

Comparison of MERLIN/SixTrack for LHC Collimation Studies

collimation, optics, scattering, proton

185

M. Serluca, R. Appleby, J. Molson
UMAN, Manchester, United Kingdom
R.J. Barlow, H. Rafique, A.M. Toader
University of Huddersfield, Huddersfield, United Kingdom
R. Bruce, A. Marsili, S. Redaelli, B. Salvachua
CERN, Geneva, Switzerland
C. Tambasco
University of Rome La Sapienza, Rome, Italy

Simulations of the LHC collimation system have been carried out in previous years with the well known SixTrack code with collimation features. MERLIN is a C++ accelerator physics library that has been extended to perform collimation studies. The main features of the code are: its modular nature, allowing the user to easily implement new physics processes such as resistive wakefields and synchrotron radiation, improved scattering routines and the MPI protocol for parallel execution. MERLIN has been configured to use the same scattering routines as SixTrack in order to benchmark the code for the LHC collimation system. In this paper we present a detailed comparison between MERLIN and SixTrack for optics and cleaning inefficiency calculation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO061

Study of the Beam Lifetime at the Synchrotron Light Source DELTA

scattering, electron, synchrotron, vacuum

222

M.A. Jebramcik, H. Huck, S. Khan, R. Molo
DELTA, Dortmund, Germany

DELTA is a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The beam lifetime, which is a critical issue for user operation of a light source, was studied experimentally and by simulation for different operation modes, i.e. single-bunch and multibunch fill patterns and for different beam currents. The electron loss rate is dominated by residual-gas scattering (Coulomb scattering and Bremsstrahlung) and by electron-electron scattering (Touschek effect). Since these processes depend in different ways on the momentum acceptance of the storage ring, a variation of the RF cavity voltage allows to disentangle their respective contributions to the total loss rate. The experimental results lead to a consistent picture for different operation modes with a characteristic dependence of the residual-gas pressure on the beam current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO061

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO068

Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation

synchrotron, storage-ring, operation, optics

237

P. Schönfeldt, A. Borysenko, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, S. Naknaimueang, M. Schuh, M. Schwarz, J.L. Steinmann
KIT, Karlsruhe, Germany

The ANKA electron storage ring of the Karlsruher Institute of Technology (KIT, Germany) is regularly operated in low-alpha mode to produce short bunches for the generation of coherent synchrotron radiation (CSR). This paper evaluates systematic bunch length measurements taken in low-alpha operation of the ANKA storage ring. Above the bursting threshold not only the emission of CSR occurs in bursts, but also a continuous fluctuation of the bunch's length is observed. The measurements were carried out using concurrent multi turn (using a streak camera) as well as single shot (using electro-optical spectral decoding) methods. Furthermore, we compare information obtained on the fluctuation to simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO068

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO086

On-line Beam Control with Ocelot at Siberia-2

controls, software, closed-orbit, dipole

289

S.I. Tomin, A.G. Valentinov
NRC, Moscow, Russia

Siberia-2 is a synchrotron light source with electron beam energy up to 2.5GeV, currently undergoing upgrade of controls hardware and software. Ocelot, an accelerator physics framework, was integrated with the new orbit correction system for high level beam control. We describe the steps taken for simulation studies of orbit correction strategies on a virtual machine model, integration of the software into the control system and experimental results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO086

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO090

Top-up Operation at ALBA Synchrotron Light Source

injection, operation, radiation, storage-ring

301

M. Pont, G. Benedetti, J. Moldes, R. Muñoz Horta, A. Olmos, F. Pérez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The ALBA light source has been operating in decay mode since May 2012. Now it is ready for top-up operation, which should become the standard operation mode for users from mid 2014. In this paper we are going to summarise the different steps that have taken place before the start of top-up operation: radiation safety simulations and measurements, upgrade of hardware and software interlocks, control software and injection optimisation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO090

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO108

Lattice and Start-to-end Simulation of the Mainz Energy Recovering Superconducting Accelerator MESA

lattice, linac, experiment, optics

346

R.G. Heine, K. Aulenbacher, F. Schlander, D. Simon
IKP, Mainz, Germany

Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The institute for nuclear physics (IKPH) at Mainz University is designing a multi turn energy recovery linac for particle physics experiments *. We present the current status of the lattice development of MESA together with a PARMELA start to end simulation.
* R. Heine, K. Aulenbacher, and R. Eichhorn: MESA-Sketch of an Energy Recovery LINAC for Nuclear Physics Experiments at Mainz, Proc. of the IPAC2012, New Orleans, Louisiana, USA, p. 1993-1995.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO108

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO109

Beam Loss Studies for the KEK Compact-ERL

scattering, electron, cavity, beam-losses

349

O. Tanaka, T. Furuya, K. Harada, N. Nakamura, H. Sakai, M. Shimada, K. Umemori
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan

Beam losses due to eﬀects of Touschek, residual gas, intra-beam scattering, and field emission were studied for the KEK compact Energy Recovery Linac (cERL), which is now under commissioning. By studying the beam losses of cERL, we can better understand the loss mechanisms, estimate the beam loss rates, and localize potentially dangerous areas of the beamline for the future 3GeV ERL project. The goal is to achieve a safety low-emittance and high-current beams operation which can help contribute to the beam loss study under 3GeV ERL project. We used existing and modiﬁed ELEGANT routine to perform the simulations. We also developed a MATLAB data analysis algorithm to handle the large amount of information that is outputted from the program. The data obtained then compared with the theoretical estimation to judge the computation’s accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO109

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO114

Particle Tracking Simulations with FLUKA for DESY FLASH and EXFEL

radiation, electron, neutron, photon

363

V.G. Khachatryan, V.H. Petrosyan, A. Sargsyan, A.V. Tsakanian
CANDLE SRI, Yerevan, Armenia

The objective of the study is the simulation of the produced secondary radiation properties when the electron beam halo particles hit collimator walls. Using particle tracking simulation code FLUKA the European XFEL electron beam interaction with the titanium collimator and copper absorber of the undulator intersections as well as FLASH beam interaction with the tapered collimator were simulated. Absorbed dose spatial distribution in the material of the collimators was simulated for the total secondary radiation and its important photon and neutron components. Residual dose rate after irritation of the collimator material by the electron beam was calculated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO114

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME002

Simulation of the Thermal Deformation and the Cooling of a Four-rod Radio Frequency Quadrupole

rfq, radio-frequency, quadrupole, radio-frequency-quadrupole

376

B. Masschaele, H. De Gersem, T. Roggen
KU Leuven, Kortrijk, Belgium
H. Podlech
IAP, Frankfurt am Main, Germany
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: This work is supported by the European Atomic Energy Community’s Seventh Framework Programme under grant agreement nr. 269565 (MAX project).
A four-rod radio frequency quadrupole (RFQ) contains four modulated rods kept in place by a number of stems and fixed within a resonating cavity. The position and the modulation of the rods determines the focusing and accelerating properties of the RFQ. The resonating field induces currents, and by that Joule losses, in the stems, rods and tuning plates. The temperature increase causes a mechanical deformation which may lead to a deteriorated performance of the RFQ. The temperature increase is kept small by cooling the rods and stems. A new layout of cooling channels has been proposed. The paper reports about coupled electromagnetic, fluid-dynamic, thermal and structural dynamic field simulations carried out for predicting the mechanical deformation of the stems and the rods. The results for the four-rod RFQ planned for the MYRRHA proton accelerator indicate a change of 47 μm of the distance between the rods when cooling water with a velocity of 3 m/s is applied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME003

Radio Frequency Quadrupole Surrogate Field Models Based on 3D Electromagnetic Field Simulation Results

rfq, multipole, quadrupole, electromagnetic-fields

379

T. Roggen, H. De Gersem, B. Masschaele
KU Leuven, Kortrijk, Belgium
W. Ackermann, S. Franke, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This research is funded by grant ”KUL 3E100118” ”Electromagnetic Field Simulation for Future Particle Accelerators”, Project FP7-Euratom No. 269565 and the Belgian Nuclear Research Centre (SCK•CEN)
Surrogate field models for the different sections of a Radio Frequency Quadrupole (RFQ) are developed, identified on the basis of finite element (FE) simulation and embedded in a moment method beam dynamics simulation code. The models are validated for both theoretical and realistic RFQ designs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME004

RFQ Solver based on the Method of Moments

rfq, linac, impedance, quadrupole

382

C. Raucy, C.V.G. Craeye
UCL, Louvain-la-Neuve, Belgium
D. Vandeplassche
SCK•CEN, Mol, Belgium

Funding: SCK•CEN
The aim of this research is to improve the accuracy and the simulation time of solvers devoted to Radio Frequency Quadrupoles (RFQ). The Method of Moments is a full-wave method used to solve scattering problems. Its main advantage over FE or FDTD solvers is that unknowns are limited to the boundaries of the object. The resulting dense system of equations can be solved very rapidly with the help of domain-decomposition approaches (e.g. Macro Basis Functions*), especially when the level of detail is very fine compared to the wavelength, which is definitely the case for RFQ’s. Such a method however needs a first regularization method to overcome the low-frequency breakdown in order to compute the Macro Basis Functions. The respective field contributions of different parts of the global structure (e.g. rods vs. stems) can also easily be finely investigated. Numerical results will be presented based on the Myrrha RFQ. The low-frequency breakdown issue due to the very fine mesh will be discussed and a solution based on the so-called Loop-Tree** decomposition will be detailed.
* Ozdemir, N.A.; Gonzalez-Ovejero, D.; Craeye, C., IEEE Tr.AP, vol.61, no.4, pp.2088, 2098, April 2013
** Andriulli, F.P., IEEE Tr.AP, vol.60, no.5, pp.2347, 2356, May 2012

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME005

Simulation of the Extraction and Transport of a Beam from the SILHI Source with the Warp Code

ion, plasma, extraction, space-charge

385

A. Chancé, N. Chauvin
CEA/DSM/IRFU, France

In a low energy beam transfer (LEBT) line, space charge effects are dominant and make the motion of the particles strongly non-linear. So, the beam dynamics is directly dependent on the 6D distribution of the particles after the ion source extraction system. It is thus essential to simulate accurately the source extraction region and the space charge compensation after it to try to reach an agreement between the simulations and the measurements. Generally, the ion source extraction system is simulated with electrostatic codes (often using simple model for space charge) from which the 6D beam distribution is derived. Then, this distribution can be used as an initial condition to simulate the beam transport in the LEBT with a time dependent PIC code that takes into account space charge compensation. We propose here to simulate accurately the SILHI source extraction system with the Warp and AXCEL-INP codes. The SILHI ion source will be quickly presented and some simulations results will be given and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME008

3d Full Electromagnetic Beam Dynamics Simulations of the Pitz Photoinjector

laser, cathode, gun, emittance

391

Y. Chen, E. Gjonaj, W.F.O. Müller, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: work supported by DESY, Hamburg and Zeuthen sites
The electromagnetic (EM) simulation software CST STUDIO SUITE® * has been applied to investigate the beam dynamics for the electron gun of the Photo Injector Test facility at DESY, Zeuthen site (PITZ). A series of 3D beam dynamics simulations are performed to study the bunch injection process at PITZ with the objective of clarifying the discrepancies between measurements and simulations. Multiple comparisons are presented for the transverse emittance and the total emitted charge between the measurement data and simulation results using CST STUDIO SUITE®and Astra **.
* Computer Simulation Technology AG, website: http://www.cst.com/
** K. Floettmann A Space Charge Tracking Algorithm, user manual (version 3), 2011

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME010

A MAD-X Model of the HIT Accelerator

ion, synchrotron, dipole, controls

397

R. Cee, M. Galonska, T. Gläßle, Th. Haberer, K. Höppner, A. Peters, S. Scheloske
HIT, Heidelberg, Germany

For a medical accelerator facility like the Heidelberg Ion-Beam Therapy Centre (HIT) an online simulation tool with read and write access to the control system and the database is essential for effective beam alignment and beam spot size adjustment at the patient position. Since the commissioning of HIT the simulation programme Mirko from GSI Darmstadt has been in use for the simulation of the beamlines and the synchrotron. While Mirko fully complies with the demands and is still in regular use, the long-term support of the HIT-Mirko derivate cannot be guaranteed. We have therefore started to set up a new simulation environment based on the MAD-X programme from CERN. In a first step we built a MAD-X model of the HIT accelerator using the MAD-X export function of Mirko. The resulting sequences were transformed and extended into executable MAD-X files. The simulation results were validated against Mirko and a good agreement of the calculated beam envelopes could be achieved. Works on the graphical user interface (GUI) for visualisation of and interaction with the beam envelopes and the link to the control system are in progress.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME011

Matrix Integration of ODEs for Spin-orbit Dynamics Simulation

lattice, operation, quadrupole, resonance

400

A.N. Ivanov, Y. Senichev
FZJ, Jülich, Germany

MODE (Matrix integration of Ordinary Differential Equations) is a software package that provides nonlinear matrix maps building for spin-orbit beam dynamics simulation. In this article we briefly describe the developed integrated development environment features and present computational comparison with other simulation tools. MODE mathematical model is based on Newton-Lorentz and T-BMT equations that are expanded to Taylor series up to the necessary order of nonlinearity. The numerical algorithm is based on matrix presentation of Lie propagator. Spin-orbit simulation results of MODE are compared with results of COSY Infinity and OptiM. MODE provides a flexible graphic user interface, code auto complete technology and visual designer for accelerators. There is also a possibility to generate codes in different programming languages and parallelization techniques.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME012

A New Tool for Automated Orbit and Spin Motion Analysis

lattice, experiment, software, storage-ring

403

D. Zyuzin
FZJ, Jülich, Germany

There are a lot of tools to simulate beam dynamics in accelerators of various types. Many of them are intended to use for specific purposes, and there are universal codes that can simulate both orbit and spin motion in magnetic and electrostatic structures. To start using these codes beam physicist first should have learn syntax, know features and methods how to describe lattice and beams in this particular code. Output data structures of different simulation programs are also vary and depend on peculiarities of each program. This paper proposes a new tool for automated generation and execution of input files for simulation programs and for data analysis of output data. The developed tool allows to describe a lattice, calculate different lattice parameters (like tunes) using simulation program, track particles inside the lattice and analyze various parameters of output data (like beam depolarization). Simulations and analysis can be done in parallel using built-in parallelization mechanisms, and all results can be stored in the database and can be easily fetched when needed. The tool is used to simulate beam and spin dynamics in different lattices to increase spin coherence time.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME013

A Python Poisson Solver for 3D Space Charge Computations in Structures with Arbitrary Shaped Boundaries

rfq, space-charge, electron, ion

406

G. Pöplau, C. Potratz
COMPAEC e.G., Rostock, Germany

Numerical techniques in the field of particle accelerators are mainly driven by the design of next-generation accelerators: The need for higher simulation complexity and the necessity for more and more specialized algorithms arises from the ever increasing need to include a broader range of physical effects and geometrical details in a computer simulation. This, on the other hand requires fast and reliable simulation tools for a limited user base. Therefore, new approaches in simulation software development are necessary to provide useful tools that are well-suited for the task at hand and that can be easily maintained and adapted by a small user community. We show how Python can be used to solve numerical problems arising from particle accelerator design efficiently. As model problem, the computation of space charge effects of a bunch in RFQs including the vane geometry was chosen and a suited solver was implemented in Python.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME014

Automated Mode Recognition Algorithm for Accelerating Cavities

cavity, coupling, polarization, dipole

409

K. Brackebusch, T. Galek, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by Federal Ministry for Research and Education BMBF under contract 05K13HR1.
Eigenmode simulations of accelerating structures often involve a large number of computed modes that need to be catalogued and compared. In order to effectively process all the information gathered from eigenmode simulations a new algorithm was developed to automatically recognize modes’ field patterns. In this paper we present the principles of the algorithm and investigate its applicability by means of different single and multi cell cavities. The highest achievable order of correctly recognized modes is of particular interest.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME018

Quantification of Geometric Uncertainties in Single Cell Cavities for BESSY VSR using Polynomial Chaos

cavity, HOM, linac, SRF

415

J. Heller, T. Flisgen, C. Schmidt, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Federal Ministry for Research and Education Germany under contract 05K13HR1
The electromagnetic properties of SRF cavities are mostly determined by their shape. Due to fabrication tolerances, tuning and limited resolution of measurement systems, the exact shape remains uncertain. In order to make assessments for the real life behaviour it is important to quantify how these geometrical uncertainties propagate through the mathematical system and influence certain electromagnetic properties, like the resonant frequencies of the structure's eigenmodes. This can be done by using non-intrusive straightforward methods like Monte-Carlo (MC) simulations. However, such simulations require a large number of deterministic problem solutions to obtain a sufficient accuracy. In order to avoid this scaling behaviour, the so-called polynomial chaos (PC) expansion is used. This technique allows for the relatively fast computation of uncertainty propagation for few uncertain parameters in the case of computationally expensive deterministic models. In this paper we use the PC expansion to quantify the propagation of uncertain geometry on the example of single cell cavities used for BESSY VSR as well as to compare the obtained results with the MC simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME019

Study of a Fast Convolution Method for Solving the Space Charge Fields of Charged Particle Bunches

space-charge, electron, ion, electromagnetic-fields

418

D. Zheng, A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

The kernel of beam dynamics simulations using the particle-in-cell (PIC) model is the solution of Poisson's equation for the electric potential. A very common way to solve Poisson's equation is to use the convolution of charge density and Green's function, the so-called Green's function method. Additionally, the integrated Green's function method* is being used in order to achieve a higher accuracy. For both methods, the convolutions are done using fast Fourier transform based on the convolution theorem. However, the construction of the integrated Green's function and the further convolution is still very time-consuming. The computation can be accelerated without loosing precision if the calculation of Green’s function values is limited to that part of the computational domain with non-zero grid charge density. In this paper we present a general numerical study of these Green's function methods for computing the potential of different bunches: The results can also be used in other simulation codes to improve efficiency.
* J. Qiang, S. Lidia, R. D. Ryne, and C. Limborg-Deprey, “A Three-Dimensional Quasi-Static Model for High Brightness Beam Dynamics simulation,” Phys. Rev. ST Accel. Beams, vol 9, 044204 (2006).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME022

Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna

plasma, ion, operation, experiment

424

H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME023

A High Precision Particle-moving Algorithm for Particle-in-cell Simulation of Plasma

electron, cyclotron, plasma, experiment

427

X.F. Li, D.Z. Chen, D. Li, H.K. Yue
HUST, Wuhan, People's Republic of China

A new particle-moving algorithm for particle-in-cell simulation of plasma is developed based on the Linear Multistep Method. The conventional and the new algorithms are investigated by numerical experiments, which are conducted in three typical fashions of the electron motions in electromagnetic fields, that is, cyclotron in homogeneous magnetic field, drift in field and motions in inhomogeneous magnetic field. The new algorithm not only improves the accuracy but also relaxes the time step condition for the simulation. It can increase the computation efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME025

New Possibilities of MultP-M Code

multipactoring, electron, RF-structure, operation

433

M. Gusarova, S. Khudyakov, I.I. Petrushina, Ya.V. Shashkov
MEPhI, Moscow, Russia

Implementation and Testing of the new module package for geometry import of the MultP-M 3D code for multipacting prediction was performed. The results of simulations for the coaxial line specimen using this new module are presented. These results are compared with analytical calculations and experimental data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME026

IBS Simulations with Compute Unified Device Architecture (CUDA) Technology

scattering, GPU, factory, electron

436

S.A. Glukhov, E.B. Levichev, S.A. Nikitin, P.A. Piminov, D.N. Shatilov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

A program code for 6D tracking has been developed taking into account IBS (Intra-Beam Scattering) and Touschek effect and using Monte-Carlo method. The simulation algorithm has been developed on the basis of well-known IBS theory presented in (*). The resulting program can be executed using GPGPU devices (General-Purpose Graphics Processing Units) supporting CUDA technology (Compute Unified Device Architecture).
* J. Le Duff, Single and multiple Touschek effects // Published in In Rhodos 1993, Advanced accelerator physics, vol. 2 573-586. CERN Geneva - CERN-95-06 (95/11,rec. Mar.96) 1993. p. 573-586.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME027

Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders

collider, linear-collider, beam-beam-effects, positron

439

M.A. Boronina, V.D. Korneev, V.A. Vshivkov
ICM&MG SB RAS, Novosibirsk, Russia

We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME029

Simulation of Low Energy Charged Particle Beams

electron, cyclotron, extraction, quadrupole

442

O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Low energy particle beams pose specific challenges to simulation codes and experiments alike as a number of effects become important that can often be neglected at higher beam energies, including e.g. space-charge or fringe field effects. The optimization of low energy charged particle beam transport through arbitrary electromagnetic fields is the purpose of a code aimed at tracking low-energy particles from the sub-eV to the MeV energy range with high precision. The code is based on Matlab/Simulink and able to use 3-dimensional field maps from either Finite Elements Method (FEM) solvers, such as Comsol, OPERA 3D or CST particle studio, fields calculated by the code itself, or field maps from measurements. This contribution describes the code structure and presents its performance limitations. It also gives a summary of results obtained from beam dynamics simulations of cyclotrons injection systems, storage ring extraction systems, electrostatic and magnetic beamlines, as well as from photocathode optimization studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME032

PIC Simulations in Low Energy Part of PIP-II Proton Linac

rfq, emittance, linac, proton

448

G.V. Romanov
Fermilab, Batavia, Illinois, USA

The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME033

Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

electron, collider, gun, solenoid

451

G. Stancari
Fermilab, Batavia, Illinois, USA
V. Moens
EPFL, Lausanne, Switzerland
S. Redaelli
CERN, Geneva, Switzerland

Funding: Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC02-07CH11359 with the US Department of Energy. Research supported in part by US LARP and EU FP7 HiLumi LHC, Grant Agreement 284404.
Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME035

Current Status of the GPU-Accelerated ELEGANT

GPU, operation, acceleration, linac

454

I.V. Pogorelov, K.M. Amyx, J.R. King
Tech-X, Boulder, Colorado, USA
M. Borland, R. Soliday
ANL, Argonne, Ilinois, USA

Funding: Work supported by the DOE Office of Science, Office of Basic Energy Sciences grant No. DE-SC0004585, and in part by Tech-X Corporation.
Efficient implementation of general-purpose particle tracking on GPUs can result in significant performance benefits to large-scale tracking simulations. This presentation is an update on the current status of our work on accelerating Argonne National Lab’s particle accelerator simulation code ELEGANT using CUDA-enabled GPU. We summarize the performance of beamline elements ported to GPU, and discuss optimization techniques for some important collective effects kernels, in particular our methods of avoiding costly thread contention. We also present preliminary results of a scaling study of the GPU-accelerated version of the code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME037

The Development of Stochastic Processes in COSY Infinity

scattering, emittance, lattice, controls

457

J.D. Kunz
IIT, Chicago, Illinois, USA
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by U.S. Department of Energy.
COSY Infinity is an arbitrary-order beam dynamics simulation code. It can determine high-order transfer maps of combinations of particle optical elements. New features are being developed for inclusion in COSY to follow the distribution of particles through matter. To study in detail the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte-Carlo approach in which transfer map methods describe the average behavior of the particles including energy loss, and Monte-Carlo methods are used to provide small corrections to the predictions of the transfer map accounting for the stochastic nature of scattering and straggling of particles. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed will aid the optimization of muon cooling channels. Progress on the development of the required algorithms is reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME038

Space Charge Simulation in COSY using The Fast Multipole Method

space-charge, emittance, multipole, collider

460

B.T. Loseth, M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Fermilab, Batavia, Illinois, USA
H. Zhang
JLab, Newport News, Virginia, USA

A method is implemented in COSY Infinity that allows the computation of space charge effects of arbitrary and large distributions of particles in an efficient and accurate way based on a variant of the Fast Multipole Method (FMM). It relies on an automatic multigrid-based decomposition of charges in near and far regions and the use of high-order differential algebra methods to obtain decompositions of far fields that lead to an error that scales with a high power of the order. Given an ensemble of N particles, the method allows the computation of the self-fields of all particles on each other with a computational expense that scales as O(N). Furthermore, the method allows the computation of all high-order multipoles of the space charge fields that are necessary for the computation of high-order transfer maps and all resulting aberrations. Space charge effects are crucial in modeling the latter stages of the six-dimensional (6D) cooling channel for the Muon Collider. Results of simulating the 6D cooling channel for the Muon Collider using the FMM method and other tools and improvements implemented for ionization cooling lattices are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME043

Modeling and Simulation of Beam-induced Plasma in Muon Cooling Devices

plasma, cavity, electron, ion

466

K. Yu
SBU, Stony Brook, USA
M. Chung, A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA
V. Samulyak
SUNY SB, Stony Brook, New York, USA

Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. We have developed numerical algorithms and parallel software for self-consistent simulation of the plasma production and its interaction with particle beams and external fields. Simulations support the experimental program on the hydrogen gas filled RF cavities in the Mucool Test Area (MTA) at Fermilab. Computational algorithms are based on the electromagnetic particle-in-cell (PIC) code SPACE combined with a probabilistic, macroparticle-based implementation of atomic physics processes such as the absorption of the incident particles, ionization of the absorber material, and the generation and evolution of secondary particles in dense, neutral gas. In particular, we have proposed a novel algorithm for dealing with repetitive incident beam, enabling simulations of long time scale processes. Benchmarks and simulations of the experiments on gas-filled RF cavities and prediction for future experiments are discussed.
* kwangmin.yu@stonybrook.edu
** rosamu@bnl.gov

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME047

Comparison of the Results of a Hydrodynamic Tunneling Experiment with Iterative FLUKA and BIG2 Simulations

target, proton, experiment, collider

479

F. Burkart, J. Blanco, D. Grenier, R. Schmidt, D. Wollmann
CERN, Geneva, Switzerland
N.A. Tahir
GSI, Darmstadt, Germany

In 2012, a novel experiment has been performed at the CERN HiRadMat facility to study the impact of a 440 GeV proton beam generated by the Super Proton Synchrotron (SPS), on extended solid copper cylindrical targets. Substantial hydrodynamic tunneling of the protons in the target material has been observed. Iterative FLUKA and BIG2 simulations with the parameters of the actual experiment have been performed. In this paper the results of these simulations will be discussed and compared to the experimental measurements. Furthermore, the implication on the machine protection design for high intensity hadron accelerators as the current LHC and the future High Luminosity LHC will be addressed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME070

Investigation of a High Power, Low Impedance Pulse Forming Network based on Ceramic Capacitors

impedance, network, experiment, laser

529

J. Gao, X.J. Ge, J. He, J. Liu
NUDT, Changsha, People's Republic of China

Solid state is one of the most important development directions for pulsed power technologies. For GW level pulse generators, switches and pulse forming units are difficult to implement with solid state components restricted by high power tolerance and high voltage insulation. Under certain pulse power, operation voltage is decided by impedance of the pulse forming unit, which means that pulse modulation with low impedance method should help improve insulation strength of a pulsed power system. Therefore, a high power, low impedance pulse forming network is developed based on solid components of ceramic capacitors in this research. It is designed that the impedance is 1.6 Ω, the pulse width is about 150 ns, and the output power is above 1 GW. Low impedance is accomplished via several pulse forming units connected in parallel with a circumferential structure, which could reduce the stray inductance due to good symmetrical characteristics. Key factors influencing pulse modulation process are investigated, stray parameters are examined by electromagnetic calculations and preliminary experiments are carried out, with results giving reasonable agreement with the theoretical cases.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME075

Cooling of the LHC Injection Kicker Magnet Ferrite Yoke: Measurements and Future Proposals

vacuum, kicker, injection, operation

544

M.J. Barnes, S. Bouleghlimat, L. Ducimetière, M. Garlaschè, V. Gomes Namora, T. Kramer, R. Noulibos, Y. Sillanoli, Z.K. Sobiech, W.J.M. Weterings
CERN, Geneva, Switzerland

LHC operation with high intensity beam, stable for many hours, resulted in significant heating of the ferrite yoke of the LHC Injection Kicker Magnets. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. The beam screen, which screens the ferrite yoke from wakefields, has been upgraded to limit ferrite heating. In addition it is important to improve the cooling of the ferrite yoke: one method is to increase the internal emissivity of the cylindrical vacuum tank, in which the kicker magnet is installed. This paper describes a method developed for measuring the emissivity of the inside of the tanks, which has been benchmarked against measurements of the ferrite yoke temperature during heat treatment in an oven and transient thermal simulations. Conclusions are drawn regarding an ion bombardment technique evaluated for improving emissivity without degrading vacuum properties. In addition initial concepts for improved cooling are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME075

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME081

A Stripline Kicker Driver for the Next Generation Light Source

kicker, high-voltage, coupling, impedance

559

F.M. Niell, N. Butler, M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: US Department of Energy, Award DE-SC00004255
Diversified Technologies, Inc. (DTI) assembled a prototype pulse generator capable of meeting the original specifications for the Next Generation Light Source (NGLS) fast deflector. The ultimate NGLS kicker driver must drive a 50 Ω terminated Transverse Electromagnetic (TEM) deflector blade at 10 kV, with flat-topped pulses and a sustained repetition rate of 100 kHz. Additional requirements of the specification include a 2 ns rise time (10 – 90%), a highly repeatable flattop with pulse width from 5 – 40 ns, and a fall time less than 1 μs (down to 10-4 of the peak value). The driver must also effectively absorb high-order mode signals emerging from the deflector itself. It is envisioned that a scintilla of deflection will be imparted by a symmetric pair of shaped parallel deflection blades, pulsed in opposition at 10 kV. Within the guide, each TEM wave produced by the two pulse generators traverses the guide synchronously with the selected (relativistic) charge packet. The DTI team has designed and demonstrated the key elements of a solid state kicker driver capable of meeting the NGLS requirements, with possible extension to a wide range of fast-pulse applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME081

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI003

Positron Yield Optimization by Adjusting the Components Offset and Orientation

positron, target, electron, injection

576

L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama
KEK, Ibaraki, Japan
S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI010

Laser Ablation Ion Source for the KEK Digital Accelerator

ion, laser, extraction, space-charge

598

N. Munemoto
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
Y. Fuwa, S. Ikeda, M. Kumaki
RIKEN, Saitama, Japan
Y. Fuwa
Kyoto ICR, Uji, Kyoto, Japan
S. Ikeda, K. Takayama
TIT, Yokohama, Japan
M. Kumaki
RISE, Tokyo, Japan
M. Okamura
BNL, Upton, Long Island, New York, USA
S. Takano, K. Takayama
KEK, Ibaraki, Japan
K. Takayama
Sokendai, Ibaraki, Japan

KEK Digital Accelerator (DA) is a small scale induction synchrotron and operated at 10Hz and recently has succeeded to accelerate gaseous ions*. There is a strong demand of fully striped carbon ions because the DA is regarded as the second generation of cancer therapy driver, which does not require an injector and electron stripper. We need a novel carbon ion source providing C⁶⁺ beams, which are directly injected into the DA and accelerated up to required energy. For this purpose, a laser ablation ion source(LAIS) is promising**. To obtain high yield C⁶⁺ ions from ablation plasma, the laser irradiation condition has been evaluated and relationship between beam properties of charge spectrum, intensity, and temperature, and carbon target materials were examined. Two laser systems, long pulse (6 ns) and short pulse (170 ps), were employed to irradiate a graphite and amorphous carbon target. The current densities and profile of the generated plasmas in time were measured and charge state distributions were analyzed. In addition we will report a full design integrating this LAIS, the extraction system, the longitudinal chopper system, and the low energy beam transport line.
* T.Yoshimoto et al., presented in this conference
** N.Munemoto et al., Proceedings of ICIS2013, published in Rev. Sci. Inst.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI023

Simulation of the ELBE SRF Gun II

gun, emittance, SRF, laser

636

P.N. Lu, A. Arnold, U. Lehnert, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
HZDR, Dresden, Germany

Funding: EuCARD, contract number 227579 German Federal Ministry of Education and Research grant 05 ES4BR1/8 LA³NET, Grant Agreement Number GA-ITN-2011-289191
By combining the code of ASTRA and elegant in a user-friendly interface, a simulation tool is developed for the ELBE SRF Gun II. The photoelectric emission and first acceleration to several MeV in the gun cavity are simulated by ASTRA with a 1D Model, where the space charge effect is considered. The dependence of the beam quality on key parameters is studied, and a compromised optimization for a 77 pC beam is used for further elegant simulation of the beam transport through a dogleg and ELBE Linacs. Proper settings of the magnets and RF phases are the main targets of improving the beam quality. Up to now the best simulation result is an electron bunch with the energy of 47 MeV, energy spread of 66 keV, bunch length of 0.35 ps and transverse emittance of 1.9 μm and 2.7 μm in the two perpendicular directions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI026

Complete Simulation of Laser Induced Field Emission from Nanostructures Using a DGTD, PIC and FEM Code

electron, laser, cathode, space-charge

645

A. Fallahi, F.X. Kärtner
CFEL, Hamburg, Germany
K.K. Berggren, R. Hobbs, F.X. Kärtner, P.D. Keathley, M.E. Swanwick, L.F. Velasquez-Garcia, Y. Yang
MIT, Cambridge, Massachusetts, USA

Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg.
We present a general and efficient numerical algorithm for studying laser induced field emission from nanostructures. The method combines the Discontinuous Galerkin Time Domain (DGTD) method for solving the optical field profile, the Particle-In-Cell (PIC) method for capturing the electron dynamics and the Finite Element Method (FEM) for solving the static field distribution. The charge distribution is introduced to the time-domain method based on a modified Fowler-Nordheim field emission model, which accounts for the band-bending of the charge carriers at the emitter surface. This algorithm is capable of considering various effects in the emission process such as space-charge, Coulomb blockade and image charge. Simulation results are compared with experimental findings for optically driven electron emission from nanosharp Si-tips.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI028

Different Countermeasures of Electron Amplification in the Photocathode Unit

cathode, electron, SRF, gun

652

E.T. Tulu, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Arnold
HZDR, Dresden, Germany

Funding: Federal Ministry for Research and Education BMBF; Project: 05K2013-HOPE
Superconducting radio frequency (SRF) structures may be subjected to electron multipacting (MP). The electrons emitted from one of the structure’s wall under certain conditions are accelerated by the RF field, thereby they may impact the wall again based on the field pattern in the structure. Accordingly the number of electrons increases exponentially caused by secondary electron emission*. The latter depends on the secondary emission coefficient of the surface material and the electron trajectory in the device under study**. This phenomenon limits the accelerating gradient in the cavity, moreover, it might cause an impair of RF components and distortion of the RF signal. Therefore, there should be an efficient countermeasure to suppress MP in order to boost the performance of the SRF gun. In this paper, three techniques of suppression of MP from the vicinity of the cathode, such as DC-bias, geometric modification and the microstructure of the cathode's surface, in the Rossendorf SRF gun are presented. The simulation has been done using CST Microwave Studio® and CST Particle Studio®***. Eventually, the efficient suppression method would be chosen for this particular case.
* H.Padamsee, J. Knobloch and T. Hays, 1998, Ch. 10.
** E. T. Tulu, A. Arnold and U. van Rienen, 16th International Conference on SRF, Paris, France, 2013.
*** CST AG, http://www.cst.com.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI030

Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun

cavity, gun, electron, vacuum

658

T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai
LEBRA, Funabashi, Japan
M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida
KEK, Ibaraki, Japan
T.S. Shintomi
Nihon University, Tokyo, Japan

Funding: This research was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryocooled C-band photocathode RF gun operating at 20K is under design at Nihon University. The RF gun is of BNL-type 2.6-cell pillbox cavity with a resonant frequency of 5712 MHz. With high-purity Oxygen-free copper used as the cavity material, the quality factor of the cavity is expected to be approximately 60000 from theoretical prediction of the anomalous skin effect at low temperatures. Considering the cooling capacity, initial operation of the RF gun is assumed at a duty factor of 0.01%. The cavity elements designed for low-power test is in preparation for machining. The low-power test at room temperature is scheduled early spring in 2014 before assembled at KEK by means of diffusion bonding technique. Since it is intended for the basic understanding and measurements of low temperature RF properties, the cavity is not equipped with structures for the photocathode assembling or the RF input coupler. The cavity design and the results of RF properties measured at room temperature before diffusion bonding will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI039

Ultra-short Electron Bunch Generation using Energy-chirping Cell Attached RF Electron Gun

gun, electron, cavity, radiation

685

K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio
Waseda University, Tokyo, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan
T. Takatomi, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by JSPS Grant-in-Aid for Young Scientists (B) 23740203 and Scientific Research (A) 10001690
We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-RF-Gun) for generating ultra-short electron bunches. ECC-RF-Gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3THz. It is clear that the bunch length was short enough to generate 0.3THz, which corresponds to less than 500fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-RF-Gun, the recent results of bunch length measurement and future prospective will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI040

Design and Analysis of an Electron Beam in an Electron Gun for X-Ray Radiotherapy

electron, gun, cathode, emittance

688

J.C. Lee, J.-S. Chai, M. Ghergherehchi, H.S. Kim, Y.S. Lee, S. Shin, Y.H. Yeon
SKKU, Suwon, Republic of Korea
B.N. Lee
KAERI, Dae-jeon, Republic of Korea

Funding: This work was supported by (IT R&D program of MSIP/KEIT [10043897] and MOTIE [13-DU-EE-12]) in KOREA.
Electron linear accelerators are used as x-ray generators for diagnosing the human body. In this paper conceptual design of electron beam for compact electron gun was calculated by using EGN2w and CST-Particle Studio codes. The structure of the electron gun was used for Pierce and diode type and the specification of electron beam was selected as 500 cGy/min. Specifications of designed electron gun were focused on current, beam size and normalized emittance. Optimized beam current, diameter and normalized emittance are 226.88 mA, 0.689 mm (Full width) and 1.03π mm• mrad, respectively by using two simulation codes. Accuracy of simulation was verified by comparison of emitted beam current which has error of 0.74%.
* Subhash C. Sharma et al., Journal of applied clinical medical physics, 8, 3 (2007) 119-125.
* Yuichiro Kamino et al., Med. Phys. 34 (2007) 1797-1808.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI051

Measurements of the Longitudinal Energy Distribution of Low Energy Electrons

cathode, electron, laser, experiment

720

L.J. Devlin, O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.J. Devlin, O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by STFC Cockcroft Core Grant No.ST/G008248/1
The Transverse Energy Spread Spectrometer (TESS) is an ASTeC experiment designed to measure the energy of electrons from different cathode materials. It is a dedicated test stand for future light sources. A full particle tracking code has been developed in the QUASAR Group, which simulates particle trajectories through TESS. Using this code it is possible to simulate different operational conditions of the experiment and cathode materials. The simulation results can then be benchmarked against experimental data to test the validity of the emission and beam transport model. Within this paper, results from simulation studies are presented and compared against experimental data as a collaboration within the Cockcroft Institute between ASTeC and the QUASAR Group for the case of measuring the longitudinal velocity distribution of electrons emitted from a gallium arsenide cathode using a grid structure as an energy filter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI069

Computing Angularly-resolved Far Field Emission Spectra in Particle-in-cell Codes using GPUs

radiation, plasma, laser, GPU

761

R.G. Pausch, H. Burau, M.H. Bussmann, J.P. Couperus, A.D. Debus, A. Huebl, A. Irman, A. Köhler, U. Schramm, K. Steiniger, R. Widera
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T.E. Cowan
HZDR, Dresden, Germany

Angularly resolved far field radiation spectra computed from the Lienard Wiechert Potentials of accelerated electrons give information on the microscopic particle dynamics. We present recent results using our many-GPU, fully relativistic 3D3V particle-in-cell code PIConGPU for which we have developed fully synthetic radiation diagnostics that is capable of computing angularly-resolved radiation spectra of more than 10¹⁰ electrons for several hundred to a thousand wavelengths and directions in a single simulation in less than a day on large-scale supercomputers. With such a technique it is possible to use precision spectroscopic methods for understanding the dynamics of electron acceleration in scenarios where other diagnostics fail. We present studies on laser-driven wakefield acceleration and astrophysical jet dynamics to underline the power of this new technique.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI077

Hi-Lumi LHC Collimation Studies with MERLIN Code

collimation, optics, scattering, proton

784

M. Serluca, R. Appleby, J. Molson
UMAN, Manchester, United Kingdom
R.J. Barlow, H. Rafique, A.M. Toader
University of Huddersfield, Huddersfield, United Kingdom

The collimation system is key to the successful operation of the LHC. Measurements and simulations of the previous run at 4 TeV have shown that the system is ready for the next step, running at 7 TeV, but at the same time some sensitive cleaning locations have been identified. In particular the dispersion suppressors downstream of the betatron cleaning region in IR7 are sensitive to single diffractive scattered protons from the collimator jaws. These particles can lead to magnet quenching. The MERLIN C++ library has been developed to exploit the functionality of an object oriented code, with improved collective effects and scattering routines. New single diffractive and elastic scattering routines, based on a fit of existing experimental data with the Regge theory of soft interactions of high energy scattering, is implemented in MERLIN. In this paper we present the impact of the new single diffractive scattering physics on the cleaning inefficiency of the LHC collimation system for the Achromatic Telescope Squeezing (ATS) PreSqueeze optics scheme, for the HL-LHC project. The results are compared with the same loss map calculated using a SixTrack+K2 like scattering routine.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI081

Beam Simulation for Improved Operation of Cyclotron NIRS-930

cyclotron, injection, experiment, extraction

797

M. Nakao, S. Hojo, K. Katagiri, A. Noda, K. Noda, A. Sugiura
NIRS, Chiba-shi, Japan
A. Goto
Yamagata University, Yamagata, Japan
T. Honma, A.K. Komiyama, T. Okada, Y. Takahashi
AEC, Chiba, Japan
V.L. Smirnov, S.B. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

Beam simulation using SNOP* code has been performed for the cyclotron NIRS-930 at NIRS in order to study beam dynamics in a cyclotron and to improve beam intensity. Each electric or magnetic field (main coil, trim coils, harmonic coils, magnetic channel, gradient corrector, grazer lens, dee electrode, inflector) were calculated by OPERA-3d, and simulated injection, acceleration, and extraction. The simulation of proton with 30 MeV extracting energy with harmonic 1 was already performed and well simulated RF phase and extraction efficiency**. Then we tried to apply SNOP to 18 MeV protons with harmonic 2. We first formed isochronous magnetic field with main and trim coils for simulating single particle. Next we optimized electric deflector and magnetic channel in order to maximize extracted particles simulating the bunch of particles. Beam loss of the simulation was compared to the experiment. And then we are optimizing position and rotation of inflector and position of puller to improve injection. We intend to apply optimized simulation parameter to actual cyclotron operation to improve beam intensity and quality.
* V.L. Smirnov, S.B. Vorozhtsov, Proc. of RUPAC2012 TUPPB008 325 (2012)
** V.L. Smirnov et al., Proc. of IPAC2012 292 (2012)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI081

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI085

IMALION – Creation and Low Energy Transportation of a Milliampere Metal Ion Beam

ion, ion-source, ECR, plasma

809

A. Silze, M. Kreller, G.H. Zschornack
DREEBIT GmbH, Dresden, Germany
U. Hartung, T. Kopte, T. Weichsel
Fraunhofer FEP, Dresden, Germany

Funding: This work is supported by the European Regional Development Fund (ERDF) and the Freistaat Sachsen (project no. 100074113 and 100074115).
IMALION – which stands for IMplantation of ALuminum IONs – is a facility originally designed for applications in photovoltaics and other branches in semiconductor industry. The idea was to create and guide a milliampere beam of low charged metal ions so that targets with a width of 20 cm and more can be irradiated homogeneously with minimal differences in intensity and entrance angle of the incoming beam over the entire surface. In this poster, we outline the solutions which had to be found during the realization of the project. This concerns the production of a milliampere metal ion current in a newly designed electron cyclotron resonance (ECR) ion source combined with an internal sputter magnetron device. Stable operation of the sputter magnetron under ECR magnetic mirror conditions has been proven by optical spectroscopy and Langmuir probe measurements. Furthermore, electrostatic and magnetic beamline elements developed for precision guiding of a low energy but high intensity beam as well as high intensity ion beam diagnostics are presented and ion beam transportation simulations are shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI085

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI091

Resonant Slow Extraction in Synchrotrons by Using Anti-symmetric Sextupole Fields

sextupole, resonance, extraction, synchrotron

827

Y. Zou, J.Y. Tang
IHEP, Beijing, People's Republic of China

This paper proposes a novel method for non-resonant slow extraction by using special anti-symmetric sextupole field in synchrotrons. The method has the potential in applications asking for stable slow extraction and in the halo collimation of very large machine such as LHC. Our studies show that the slow extraction by using anti-symmetric sextupole field has some advantages compared to the normal sextupole field which is the normal extraction method. One of them is that it can work at almost arbitrary tune, so that it can avoid the problem of the intensity variation caused by the ripples of magnet supplies. Studies by Hamiltonian theory and simulations which meet well show that the stable region only depends on the anti-symmetric sextupole field strength and the particles outside will be driven out in two directions which are similar to the second-order resonant extraction but with spiral steps as in the third-order resonance extraction. The beam can be extracted with a very stable intensity by gradually increasing the field strength. The multi-particle simulations by a self-made program have been carried out with a proton lattice designed for proton therapy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI091

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI097

Feasibility Studies for the Extraction of both LHC Beams from CERN SPS using a Common Kicker

extraction, kicker, septum, impedance

842

F.M. Velotti, W. Bartmann, C. Bracco, E. Carlier, K. Cornelis, B. Goddard, V. Kain, M. Meddahi
CERN, Geneva, Switzerland

The CERN Super Proton Synchrotron has to fulfil the demanding intensity specifications for the High Luminosity LHC (HL-LHC) era, with a doubling of the presently achieved operational beam intensity. One of the main problems to be addressed is given by impedance-driven beam instabilities. About 40 % of the total measured SPS impedance is due to the kickers, of which the extraction kickers in two of the SPS straight sections are the largest systems. A potential upgrade is explored which would strongly reduce the number of extraction kickers required in the SPS, by performing non-local extraction. In this scenario LHC Beam 1 would be kicked by the extraction kicker in SPS Long Straight Section 4 (LSS4), normally only used for Beam 2, to be extracted in LSS6. The concept and the expected performance of such a scheme are presented along with detailed simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI097

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI098

Design Studies of the Upgraded Collimation System in the SPS-to-LHC Transfer Lines

collimation, luminosity, injection, optics

845

A. Mereghetti, C. Bracco, F. Cerutti, B. Goddard, J. Hrivnak, V. Kain, F.L. Maciariello, M. Meddahi, G.E. Steele
CERN, Geneva, Switzerland
R. Appleby
UMAN, Manchester, United Kingdom

In the framework of the LHC Injectors Upgrade (LIU) Project, the collimators in the SPS-to-LHC transfer lines are presently under re-design, in order to cope with the unprecedented beam intensities and emittances required by the High Luminosity LHC (HL-LHC). Factors ruling the design phase are the robustness of the jaws on one side and, on the other side, the proton absorption and the emittance blow-up, essential for an effective protection of the equipment in the LHC injection regions and the LHC machine. In view of the new design, based on the one of the currently installed TCDI collimators and past investigations, the FLUKA Monte Carlo code is used to address these two factors. The present studies are intended to give essential feedback to the identification of viable solutions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI098

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI104

Measurement of Beam Ioniziation Loss in SIS18

ion, vacuum, injection, extraction

864

L.H.J. Bozyk, P.J. Spiller
GSI, Darmstadt, Germany

In the heavy ion synchrotron SIS18 at GSI an ion catcher system has been installed to provide low desorption surfaces for ionization beam loss to reduce dynamic vacuum effects. Medium charge state heavy ions can change their charge state in collission with residual gas molecules. Those ions are cought by the ion catcher system. The ion catcher blocks are mounted electrically insulated, such that it is possible, to directly measure the electrical current, induced by the incident ions. Changes in vacuum density during the acceleration cycle and also the energy dependent decrease of the cross sections for electron loss and electron capture can be measured by this system. Different ion catcher currents, measured during the operation with U²⁸⁺, and their interpretation are presented. The measurement of ionization beam loss is a valuable tool to benchmark the dynamic vacuum simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI104

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI106

Simulation Study of Beam Halo Collimation in the Heavy-ion Synchrotron SIS 100

ion, collimation, heavy-ion, injection

870

I.A. Prokhorov
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim, I. Strašík
GSI, Darmstadt, Germany

Funding: Work is supported by German Federal Ministry of Education and Research (BMBF) contract no. 05P12RDRBM
The FAIR synchrotron SIS-100 will be operated with high-intensity proton and heavy-ion beams. The collimation system should prevent beam loss induced degradation of the vacuum, activation of the accelerator structure and magnet quenches. A conventional two-stage betatron collimation system is considered for the operation with protons and fully-stripped ions. Particle tracking and ion-collimator interaction simulations of the collimation system were performed. The angular and momentum distributions of the scattered halo particles were described using analytical models and numerical tools like ATIMA and FLUKA. MADX was used for the multi-pass tracking simulations. The results obtained for the collimation cleaning efficiency as a function of the ion species and beam energy together with the detailed beam losses distributions along the ring circumference are presented. This work highlights the main aspects of the collimation of fully-stripped ion beams in the intermediate energy range using conventional two-stage systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI106

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI107

The Mitigation System of the Large Angle Foil Scattering Beam Loss caused by the Multi-turn Charge-exchange Injection

injection, scattering, insertion, operation

873

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
H. Harada, H. Hotchi, M. Kinsho, K. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan

Funding: Research Fellow of Japan Society for the Promotion of Science
In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and the circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we developed a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we focused on the relative angle of collimator block from scattering particles. We developed the beam based angler regulation method by the simulation and achieved the sufficient mitigation of the loss at 181 MeV injection energy. Since the injection energy will be upgraded to 400 MeV in this year, we will start to estimate again the collimator performance by the upgraded simulation set. We present this system as one of the mitigation methods of the large angle foil scattering beam loss caused by the multi-turn charge-exchange injection.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI107

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI110

Final Layout and Expected Cleaning for the First Crystal-assisted Collimation Test at the LHC

collimation, proton, injection, ion

882

D. Mirarchi, S. Montesano, S. Redaelli, W. Scandale
CERN, Geneva, Switzerland
F. Galluccio
INFN-Napoli, Napoli, Italy
A.M. Taratin
JINR, Dubna, Moscow Region, Russia

The installation in the CERN Large Hadron Collider (LHC) of two crystals in the horizontal and vertical planes was accomplished during the present LHC long shutdown (LS1) for crystal collimation studies. An appropriate layout was designed to demonstrate the principle feasibility of crystal collimation at the LHC. Extensive simulation campaigns were made to evaluate different crystal positions and parameters, in order to ensure that the main goals of these first feasibility tests in the LHC are within reach. In this paper, the final layout is presented. An overview of the considerations behind the design choices and the crystal parameters is given, and the expected performance of the system is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI110

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI111

Improvements of the Crystal Routine for Collimation Studies

proton, collimation, scattering, extraction

886

D. Mirarchi, S. Redaelli, W. Scandale
CERN, Geneva, Switzerland
A.M. Taratin
JINR, Dubna, Moscow Region, Russia
I.A. Yazynin
IHEP, Moscow Region, Russia

A routine has been implemented to simulate interactions of protons with bent crystals in the collimation version of \texttt{SixTrack}. This routine is optimized in view of producing high-statistics tracking simulations of collimation cleaning assisted by bent crystals. Fine tuning and comparisons with experimental data of coherent effects which a particle can experience in a bent crystal have been carried out. The data taken with 400 GeV beams at the CERN-SPS North Area in the framework of the UA9 experiment are used to benchmark the routine. Further checks on low probability interactions have been made, leading to significant improvements in the description of interactions with crystals. Comparisons with other simulations tools are used to increase our confidence in the scaling to higher energies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI111

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI114

Numerical Estimation of the Equivalent Dose Rate after the Irradiation of a Tungsten Collimator by a Low Energy Proton Beam

proton, cyclotron, radiation, operation

890

V. Talanov, D.C. Kiselev, M. Wohlmuther
PSI, Villigen PSI, Switzerland

The issue of activation of a Tungsten collimator by protons is considered for the incident energy of 12.2 MeV. Two different simulation approaches using the Monte Carlo programs MCNPX and FLUKA are applied to estimate the equivalent remanent dose rate after the irradiation of the collimator. The results of the numerical simulation are then compared to the measured dose levels of the collimator of the COMET cyclotron at Paul Scherrer Institut (PSI).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI114

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRI115

Activation Models of the ISIS Collectors

synchrotron, controls, operation, scattering

893

H. V. Smith, D.J. Adams, B. Jones, C.M. Warsop
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS facility at the Rutherford Appleton Laboratory is a pulsed neutron and muon source, for materials and life science research. The 163 m circumference, 800 MeV, 50 Hz rapid cycling synchrotron accelerates up to 3·10¹³ protons per pulse. The maximum operating intensity of the synchrotron is limited by loss during acceleration, mainly due to the non-adiabatic longitudinal trapping process between 0 and 3 ms, corresponding to energies between 70 and 200 MeV. In order to minimise global machine activation and prevent component damage a beam collimation, or collector, system is installed in a five metre drift section in super-period one, to localise loss to this region. This paper summarises new results from modelling of the beam collectors using the FLUKA code [1, 2]. Understanding the current performance of the collectors is important for high intensity beam optimisation and may influence future injection upgrade plans. Residual dose rates are compared to film badge measurements, predicted energy deposition results are compared to the measured heat load on the collector cooling systems and an assessment is made of the distribution of particles exiting the collector straight.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI115

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB02

Design Study of the SuperKEKB Interaction Region Optics

sextupole, octupole, quadrupole, dynamic-aperture

950

H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi, K. Oide
KEK, Ibaraki, Japan

SuperKEKB is an upgrade project of KEKB e⁺e⁻ ring collider and is aimed to open up a new luminosity frontier. The target peak luminosity is 8x10³⁵ cm^-2 s^-1. In order to achieve this target, a nano-beam scheme is adopted, in which colliding beams are squeezed to nano-scale sizes in the vertical direction at the interaction point (IP). The interaction region (IR) is an essential part of the SuperKEKB lattice design since the large chromaticity originated in the final focusing system (QCS) and strong lattice nonlinear forces make the particle motion unstable. An optics with detailed hardware specifications has been designed to optimize a performance of the beam dynamics. Design studies of IR taking into account a possible QCS imperfection are reported in this paper.

Slides TUOAB02 [9.899 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAB02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB03

Nonlinear Optics for Suppression of Halo Formation in Space Charge Dominated Beams

focusing, quadrupole, space-charge, emittance

953

Y.K. Batygin, A. Scheinker
LANL, Los Alamos, New Mexico, USA
C. Li
IMP, Lanzhou, People's Republic of China

Traditional accelerator designs utilize linear focusing elements (quadrupoles, solenoids) to provide stable particle motion. High – intensity rms - matched non - uniform beams are intrinsically mismatched with linear focusing structure. It results in space charge induced beam emittance growth and halo formation, which can be suppressed in a quadrupole channel with higher-order multipole field components. In this paper, overview of FODO quadrupole channels with arbitrary multipoles is given. Effective averaged potential is presented for the structure with periodic combination of multipole lenses and quadrupoles. Density of matched beam avoiding emittance growth and halo formation is derived. Performed analysis allows matching of realistic beam with the internal structure of the focusing field. Beam dynamics studies with suppressed halo are presented and discussed.

Slides TUOAB03 [3.404 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOAB03

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO002

Fringe Fields Modeling for the High Luminosity LHC Large Aperture Quadrupoles

quadrupole, luminosity, multipole, controls

993

B. Dalena, A. Chancé, O. Gabouev
CEA/IRFU, Gif-sur-Yvette, France
R. Appleby, D.R. Brett
UMAN, Manchester, United Kingdom
R. De Maria, M. Giovannozzi
CERN, Geneva, Switzerland
J. Payet
CEA/DSM/IRFU, France

Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Analytical evaluations of detuning with amplitude and chromatic effects show that the effect is small, but not negligible. Therefore, the effect on long-term beam dynamics is evaluated via tracking simulations. Different tracking models are compared in order to provide a numerical estimate of this effect due to the proposed inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO003

Fast Crab Cavity Failures in HL-LHC

operation, optics, luminosity, synchrotron

997

B. Yee-Rendón, R. Lopez-Fernandez
CINVESTAV, Mexico City, Mexico
J. Barranco García
EPFL, Lausanne, Switzerland
R. Calaga, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland

Crab cavities (CCs) are a key ingredient of the High-Luminosity Large Hadron Collider (HL-LHC) to ensure head on collisions at the main experiments (ATLAS and CMS) and fully profit from the smaller β* provided by the ATS optics. At KEKB, CCs have exhibited abrupt changes of phase and voltage during a time period of few LHC turns and considering the large energy stored in the HL-LHC beam, CC failures represent a serious risk to the LHC machine protection. In this paper, we discuss the effect of CC voltage or phase changes on a time interval similar to, or longer than, necessary to dump the beam. The simulations assume a realistic steady-state distribution to assess the beam losses for the HL-LHC. Additionally, some strategies are studied to mitigate the damage caused by the failures.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO006

Strong-strong Beam-beam Simulation for the LHC Upgrade

emittance, cavity, resonance, luminosity

1006

J. Qiang, S. Paret
LBNL, Berkeley, California, USA
G. Arduini, T. Pieloni
CERN, Geneva, Switzerland
J. Barranco García
EPFL, Lausanne, Switzerland

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using computing resources at the NERSC.
The LHC upgrade will significantly improve the performance of the current LHC operation with higher collision energy and luminosity. In the paper, we report on the progress in the strong-strong beam-beam simulation of the HL-LHC upgrade with crab cavity compensation. We will present the study of the effects of accelerator tune working points, dipole noise, and crab cavity noise on colliding beam emittance growth.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO006

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO010

Origins of Transverse Emittance Blow-up during the LHC Energy Ramp

emittance, luminosity, injection, brightness

1021

M. Kuhn, G. Arduini, V. Kain, A. Langner, Y. Papaphilippou, M. Schaumann, R. Tomás
CERN, Geneva, Switzerland

During LHC Run 1 about 30 % of the potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. Measurements indicated that the majority of the blow-up occurred during the energy ramp. Until the end of LHC Run 1 this emittance blow-up could not be eliminated. In this paper the measurements and observations of emittance growth through the ramp are summarized. Simulation results for growth due to Intra Beam Scattering will be shown and compared to measurements. A summary of investigations of other possible sources will be given and backed up with simulations where possible. Requirements for commissioning the LHC with beam in 2015 after Long Shutdown 1 to understand and control emittance blow-up will be listed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO014

Semi-empirical Model for Optimising Future Heavy Ion Luminosity of the LHC

luminosity, injection, kicker, heavy-ion

1033

M. Schaumann
CERN, Geneva, Switzerland

The wide spectrum of intensities and emittances imprinted on the LHC Pb bunches during the accumulation of bunch trains in the injector chain result in a significant spread in the single bunch luminosities and lifetimes in collision. Based on the data collected in the 2011 Pb-Pb run, an empirical model is derived to predict the single-bunch peak luminosity depending on the bunch's position within the beam. In combination with this model, simulations of representative bunches are used to estimate the luminosity evolution for the complete ensemble of bunches. Several options are being considered to improve the injector performance and to increase the number of bunches in the LHC, leading to several potential injection scenarios, resulting in different peak and integrated luminosities. The most important options for after the long shutdown 1 and 2 are evaluated and compared.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO017

HL-LHC Performance with a 200 MHz RF System

luminosity, impedance, cavity, electron

1043

R. Tomás, C.O. Domínguez
CERN, Geneva, Switzerland
S.M. White
BNL, Upton, Long Island, New York, USA

The HL-LHC performance could considerably benefit from having a 200 MHz RF system. This would allow to inject longer bunches with larger bunch intensity from the SPS and to perform bunch length leveling if required. We also consider the possibility of decreasing the crab cavity frequency to increase both virtual peak luminosity and luminous region. Performance estimates of various configurations are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO019

Localisation of Beam Offset Jitter Sources at ATF2

quadrupole, experiment, EPICS, damping

1049

J. Pfingstner, H. Garcia, A. Latina, M. Patecki, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

For the commissioning and operation of modern particle accelerators, automated error detection and diagnostics methods are becoming increasingly important. In this paper, we present two such methods, which are capable of localising sources of beam offset jitter with a combination of correlation studies and so called degree of freedom plots. The methods were applied to the ATF2 beam line at KEK, where one of the major goals is the reduction of the beam offset jitter. Results of this localisation are shown in this paper. A big advantage of the presented method is its high robustness especially to varying optics parameters. Therefore, we believe that the developed beam offset jitter localisation methods can be easily applied to other accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO021

Preliminary Study of Risks and Failure Scenarios for the High Luminosity Experiments in HL-LHC

luminosity, detector, cavity, experiment

1055

F. Bouly
LPSC, Grenoble Cedex, France
R. Alemany-Fernández, H. Burkhardt, D. Wollmann
CERN, Geneva, Switzerland
B. Yee-Rendón
CINVESTAV, Mexico City, Mexico

For the HL-LHC it is planned to basically double the diameter of the triplet quadruple magnets around the high luminosity insertions of the LHC. The high luminosity experiments ATLAS and CMS would like to keep a small central chamber radius close the interaction point. In the context of collider-experiment studies for the high-luminosity upgrade of the LHC, we present a first study of the possible consequences of these changes for the experimental running conditions based on detailed simulations with tracking. We have started to implement crab cavity failures and discuss first results from these simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO026

Possible Beam-beam and Levelling Scenarios for HL-LHC

luminosity, emittance, collider, hadron

1071

M.P. Crouch, R. Appleby
UMAN, Manchester, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T. Pieloni
CERN, Geneva, Switzerland

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The upgrade of the LHC from the current set-up to high luminosity performances will provide new challenges from the point of view of beam-beam as well as other collective effects and luminosity levelling. We present the current possibilities for doing luminosity levelling for HL-LHC. We explore the merits and drawbacks of each option and briefly discuss the operational implications. The simplest option being levelling with an offset between the two beams. In particular, we look at the possibility of using flat beams in the IPs for all the available options and investigate their benefits and drawbacks, using the code COMBI. Flat beams would allow an additional degree of freedom, with the levelling only required in one of the planes at any given IP. To this end, various scenarios are looked at, both with and without crab cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO027

First Beam Background Simulation Studies at IR1 for High Luminosity LHC

background, proton, detector, luminosity

1074

R. Kwee-Hinzmann, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
G. Bregliozzi, R. Bruce, F. Cerutti, L.S. Esposito, R. Kersevan, A. Lechner, N.V. Shetty
CERN, Geneva, Switzerland
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

In the High-Luminosity Large Hadron Collider (HL-LHC) Project, the LHC will be significantly upgraded to attain a peak luminosity of up to 8.5 × 10³⁴ cm^-2s^-1, thus almost an order of magnitude higher compared to the nominal machine configuration in ATLAS at IP1 and CMS at IP5. In the view of a successful machine setup as well as a successful physics programme, beam induced background studies at IP1 were performed to investigate sources of particle fluxes to the experimental area. In particular as a start of the study, two sources forming the major contributions were simulated in detail: the first one considers inelastic interactions from beam particles hitting tertiary collimators, the second one from beam interactions with residual gas-molecules in the vacuum pipe close by the experiment, referred to as beam-halo and local beam-gas, respectively. We will present these first HL-LHC background studies based on SixTrack and FLUKA simulations, highlighting the simulation setup for the design case in the HL-LHC scenario. Results of particle spectra entering the ATLAS detector region are presented for the latest study version of HL-LHC machine layout (2013).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO034

Beam-beam Interaction in the Asymmetric Energy Gold-gold Collision in RHIC

ion, emittance, experiment, collider

1093

Y. Luo, M. Blaskiewicz, M.R. Costanzo, W. Fischer, X. Gu, V.H. Ranjbar, S.M. White
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this article, we study the beam-beam interaction in the possible future gold-gold collision with different particle energies in the Relativistic Heavy Ion Collider (RHIC). With different particle energies, the center-of-mass of collision is moving in the longitudinal direction during collision. Since the RF harmonic numbers are different for the two RHIC rings, bunches collide in 110 turns followed by 10 turns without collision. In this study, the stability of particles and the beam emittance growth are calculated through numeric simulations based on a 6-D weak-strong beam-beam interaction model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO036

Start-to-end Optic of the FSF Multi-turn ERL Project

emittance, linac, injection, undulator

1099

T. Atkinson, A.V. Bondarenko, A.N. Matveenko, Y. Petenev
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association VH NG 636 and HRJRG-214
Advanced magnetic optic designs are required to meet the heavy demands of future light sources: diffraction limited emittance, femto-second pulses and low energy spread. This paper highlights the magnetic optic that is presently being investigated in the ERL-simulation group at HZB. The injector optic is based on subtle emittance compensation techniques of space charge dominated beams. The high energy arcs are designed to suppress emittance growth due to CSR through horizontal phase advance manipulation, ISR effects by keeping the radiation integrals small and reduce the degradation due to chromatic aberrations. Optimised Start-to-End beam dynamic simulations are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO037

Suppression Techniques of CSR Induced Emittance Growth in ERL Arcs

emittance, electron, synchrotron, betatron

1102

A.V. Bondarenko, T. Atkinson, A.N. Matveenko
HZB, Berlin, Germany

The Energy Recovery Linac (ERL) conception is a promising way of creating diffraction limited synchrotron light source. The high ERL beam quality (low emittance, short bunch and low energy spread) gives an opportunity to generate high brightness photon beams. One of the main requirements for the optic in such machines is the suppression of emittance growth. An important reason for beam degradation is the impact of Coherent Synchrotron Radiation (CSR) in bending magnets. CSR induced emittance dilution and methods of preservation both with and without compression are discussed in this article.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO043

Status and Computer Simulations for the Front End of the Proton Injector for Fair

proton, ion, linac, extraction

1120

C. Ullmann, R. Berezov, J. Fils, R. Hollinger, V. Ivanova, O.K. Kester, W. Vinzenz
GSI, Darmstadt, Germany
N. Chauvin, O. Delferrière
CEA/IRFU, Gif-sur-Yvette, France

FAIR - the international facility for antiproton and ion research – located at GSI in Darmstadt, Germany is one of the largest research projects worldwide. It will provide an antiproton production rate of 7·10¹⁰ cooled pbars per hour, which is equivalent to a primary proton beam current of 2·1016 protons per hour. A high intensity proton linac (p-linac) will be built, with an operating rf-frequency of 325 MHz to accelerate a 70 mA proton beam up to 70 MeV, using conducting crossed-bar H-cavities. The repetition rate is 4 Hz with an ion beam pulse length of 36 μs[1]. Developed within a joint French-German collaboration - GSI/CEA-SACLAY/IAP – the compact proton linac will be injected by a microwave ion source and a low energy beam transport (LEBT). The 2.45 GHz ion source allows high brightness ion beams at an energy of 95 keV and will deliver a proton beam current of 100 mA at the entrance of the RFQ (Radio Frequency Quadrupole) within an emittance of 0.3π mm mrad (rms). To check on these parameters computer simulations with TraceWin, IGUN and IBSIMU of the ion extraction and LEBT (Low Energy Beam Transport) are performed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO043

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO045

Simulation Studies on Beam Injection into a Figure-8 Type Storage Ring

injection, kicker, storage-ring, experiment

1126

M. Droba, A. Ates, O. Meusel, H. Niebuhr, D. Noll, U. Ratzinger, J.F. Wagner
IAP, Frankfurt am Main, Germany

The proposed figure-8 storage ring at Frankfurt University [1, 2] is based on longitudinal guiding magnetic fields and will have special features with respect to the beam dynamics. A crucial part of the ring is the injection section, where the low energy beams have to cross an area of steeply rising field – up to B = 6 T into the main ring field. An optimized magnetic channel is designed to bring the injected beam close enough to the magnetic ring flux. An ExB kicker is needed to move the injected beam from the injection channel to the main magnetic field flux allowing multi turn injection. Simulation studies concentrate on this part and will be presented, results will be discussed. A comparison with simulations for prepared scaled down experiments with existing room temperature toroids will be done.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO053

Design and Optimization of Racetrack Microtron for Laser Compton Scattered Gamma-ray Sources

electron, linac, dipole, injection

1150

R. Hajima
JAEA/ERL, Ibaraki, Japan
M. Ferdows
JAEA, Ibaraki-ken, Japan

Funding: This work is supported by Funds for Integrated Promotion of Social System Reform and Research and Development.
Racetrack microtron (RTM) is a compact accelerator to obtain electron beams with an energy above 100 MeV. Conventional RTM's have been designed to accelerate a train of electron bunch from a thermionic electron gun, where the bunch charge is typically 10 pC. In the industrial application of laser Compton scattered gamma-ray sources, RTM with 200-300 MeV electron energy will be a suitable device to produce 2-3 MeV gamma-ray beams. Single electron bunch from a photocathode RF gun is accelerated and a high-charge small-emittance beam is preferable in such RTM. In this paper, we adopt a simulation code, GPT, for design and optimization of RTM in view of high-charge and small-emittance beam generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO055

Design Status of the RISP Test Facility LEBT

rfq, ECR, linac, quadrupole

1156

R.M. Bodenstein, D. Jeon
IBS, Daejeon, Republic of Korea
J. Bahng
Kyungpook National University, Daegu, Republic of Korea

Funding: Supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science, ICT and Future Planning and National Research Foundation of Korea Project No. 2011-0032011
Raon, the rare isotope accelerator of the the Rare Isotope Science Project (RISP) in Daejeon, South Korea, is being designed to accelerate multiple-charge-state beams simultaneously. Using an Electron Cyclotron Resonance (ECR) Ion Source to produce the ions, Raon will transport the beam through two 90-degree bending magnets and a Low Energy Beam Transport (LEBT) system to a Radio Frequency Quadrupole (RFQ). In order to test the components of the injector and LEBT system, a test facility is under development. A new LEBT, based upon the LEBT of the main driver linac, is being designed to fit within the test facility’s restrictive space requirements. This work will briefly review the main driver linac LEBT design, and then discuss the current status of the test facility LEBT design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO061

Benchmarking Beam Envelope Models for the European Spallation Source

DTL, dipole, linac, space-charge

1174

I. List
Cosylab, Ljubljana, Slovenia
E. Laface
ESS, Lund, Sweden

TraceWin is used at the European Spallation Source (ESS) as the design tool, while fast and accurate on-line models will be needed during the operations. Three models are compared: the ESS Linac Simulator (ELS), TraceWin and the OpenXAL. In all of the benchmarked models, dynamics of each beam-line element is, to the first order, represented by a transfer matrix. Differences in the matrices occur, since different reference frames are used and as well different assumptions about the energy of the particles are made. General transformations of the reference frames will be presented. Using those, the comparison of transfer maps among TraceWin and OpenXAL are given. When the differences between TraceWin and OpenXAL were unclear, the benchmark versus other code, like MAD-X and Dynac was done. The best implementations were combined into a new on-line model implementation Java ELS (or JELS) and at last the comparison of the latter with TraceWin is given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO061

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO062

Improvements in the Optics Measurement Resolution for the LHC

optics, collider, dipole, operation

1177

A. Langner, R. Tomás
CERN, Geneva, Switzerland

Optics measurement algorithms which are based on the measurement of beam position monitor (BPM) turn-by-turn data are currently being improved in preparation for the commissioning of the LHC at higher energy. The turn-by-turn data of one BPM may be used more than once, but the implied correlations were not considered in the final error bar. In this paper the error propagation including correlations is studied for the statistical part of the uncertainty. The confidence level of the measurement is investigated analytically and with simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO062

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO064

Scaling Laws of Wake Field Effects for Gradient Changes in the CLIC Main Linac

linac, wakefield, emittance, damping

1183

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

The main linac of CLIC is designed to maximize the transportable bunch charge, since this parameter determines the energy efficiency of the CLIC accelerating structures. The bunch charge is limited by short-range wake field effects, which increase the projected beam emittance. For the main linac cost optimisation, it is important to understand how the charge limit scales with the change of the gradient of the accelerating structures. In this paper, we determine such a scaling law via simulations studies. It is shown that from different possible scenarios, the charge limit for a lower gradient CLIC structure scales advantageous and a relatively high charge can be used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO065

Tests of Beam-based Alignment at FACET

wakefield, linac, emittance, alignment

1186

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

Tests of Beam-Based Alignment have been performed at FACET, with successful results. A flight simulator based on PLACET has been put in place to test the correction algorithms before applying the correction to the real machine. The flight simulator not only helped studying the parameters space in a safe environment, but it also helped developing a graphical interface that the experimenter can use to set each parameter of the correction also during the on-line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO065

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO067

Beam Transport Optimization Studies of the PSI MW-Class Proton Channel

target, proton, optics, beam-losses

1189

D. Reggiani, D.C. Kiselev, T. Reiss, R. Sobbia, V. Talanov, M. Wohlmuther
PSI, Villigen PSI, Switzerland

The proton channel of the PSI high intensity proton accelerator (HIPA) transports the beam from the extraction point of the ring cyclotron through two meson production graphite targets up to the SINQ spallation source. After many years of continuous improvement, the HIPA accelerator complex has now reached the remarkable beam power of 1.4 MW. The next power upgrade is foreseen for the near future. In order to achieve this further step, an optimization of the beam optics in the proton channel is required with the goal of keeping the beam losses at a reasonable extent and, at the same time improve the beam distribution on the SINQ target.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO069

First Studies of Two-beam Tuning in the CLIC BDS

sextupole, luminosity, collider, linear-collider

1195

J. Snuverink
JAI, Egham, Surrey, United Kingdom
A. Latina, R. Tomás
CERN, Geneva, Switzerland

Beam tuning in the beam delivery system (BDS) is one of the major challenges for the future linear colliders. Up to now single beam tuning has been performed, both in simulations and experiments at the Accelerator Test Facility (ATF). However, in future linear colliders, due to fast detuning of the final focus optics both beamlines will need to be tuned simultaneously. In this paper a first two-beam tuning study for the Compact Linear Collider (CLIC) BDS is presented applying the usual toolbox of beam-based alignment (BBA) and sextupole knobs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO071

Optimization of Low Energy Electrostatic Beam Lines

quadrupole, beam-transport, kicker, ion

1202

O. Karamyshev, D. Newton, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O. Karamyshev, D. Newton, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the STFC Cockcroft Institute Core Grant No. ST/G008248/1
Electrostatic elements are frequently used for transporting low energy charged particles, as they are easy to build and operate. However, beam motion is strongly affected by effects from fringe fields, positioning and manufacturing errors of individual ion optical elements. It is important to carry out detailed studies into these effects in order to optimize beam transport. In this paper results from numerical studies with a purpose-written code are presented and compared against analytical estimates. It is shown how the results can be used to optimize the mechanical layout of the electrostatic ion optics elements, including quadrupoles and spherical deflectors. Finally, the results from beam tracking through a multi-element beam line are presented on the basis of both, matrix multiplication and numerical particle tracking.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO071

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO072

Lattice and Component Design for the Front End Test Stand MEBT at RAL

quadrupole, rfq, lattice, emittance

1205

M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
M.A. Clarke-Gayther, A.P. Letchford, D.C. Plostinar
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) linear accelerator at Rutherford Appleton laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H⁻ beam to 3MeV. The aim of FETS is to demonstrate perfect chopping using a novel 2 stage (fast / slow) chopper scheme. The beam chopper and associated beam dumps are located in the MEBT. Achieving a low emittance-growth under the influence of strong, non-linear space-charge forces in a lattice which has to accommodate the long chopping elements is challenging. The baseline FETS MEBT design is 4.3 m long and contains 7 quadrupoles, 3 rebunching cavities, a fast and slow chopper deflector and two beam dumps. In particle dynamics simulations using a distribution from an RFQ simulation as input, beam loss for the un-chopped beam is below 1% while the chopping efficiency is >99 % in both choppers. The final MEBT lattice chosen for FETS will be presented together with particle tracking results and design details of the beam line components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO072

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO075

Initial Analysis of the 4D Transfer Map in the Emma Non-Scaling Fixed Field Alternating Gradient Accelerator

coupling, betatron, quadrupole, alignment

1214

C.S. Edmonds, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
B.D. Muratori, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: STFC
The EMMA non-scaling Fixed Field Alternating Gradient accelerator (ns FFAG) is a ring consisting of 42 quadrupole pairs. The dipole fields which guide particles around the ring are arrived at through offsetting the quadrupoles from a reference axis. In the ideal case, first order 4D transfer maps will describe the turn by turn progression of a particle bunch in transverse phase space. This contribution sees the use of experimental data to calculate the 4D transfer map for EMMA at several different momenta, and a comparison made with maps produced through simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO075

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO078

AREAL Solenoid, Dipole and Steering Magnets Design and Performance

dipole, solenoid, electron, magnet-design

1223

A.V. Tsakanian, H. Gagiyan, A.A. Gevorgyan, B. Grigoryan, V.G. Khachatryan, M. Manukyan, T.H. Mkrtchyan, S. Naghdalyan, A.S. Simonyan, V. V. Vardanyan
CANDLE SRI, Yerevan, Armenia

The AREAL solenoid, dipole and corrector magnets design, simulations and performance are presented. A solenoid magnet will be used for the focusing of the low energy (E~5MeV) electron beam after RF gun as well as in the beam diagnostic section. The magnetic iron cover of solenoid provides return path for magnetic field screening effectively the field in the outer space and concentrating it inside solenoid gap. The dipole magnet is part of the spectrometer for beam energy spread measurements. An Iron-free corrector magnet design allows independent horizontal and vertical beam steering. The design optimization and magnetic field calculations are performed using CST-EM Studio. A good agreement between measurements and simulations is obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO078

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO086

Iranian Light Source Facility Storage Ring Low Field Magnets

quadrupole, sextupole, dipole, storage-ring

1241

F. Saeidi, J. Dehghani, J. Rahighi, M. Razazian, A. Shahveh
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran
R. Pourimani, F. Saeidi
Arak University, Arak, Iran

Iranian Light Source Facility (ILSF) is a 3 GeV Synchrotron light source with the circumference of 489.6 m. Using locally available material and the emittance of less than 1 nm-rad are two main points of the ILSF storage ring lattice, consisting of 56 low field pure bending magnets, 252 quadrupoles and 196 sextupoles with additional coils for the correctors and skew quadrupoles. The physical designs of these magnets have been performed relying on two dimensional codes POISSON [1] and FEMM [2]. Three dimensional RADIA [3] was practiced too, to audit chamfering values.
Farhad. Saeidi@Ipm.ir

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO086

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO092

Magnetic-field Variable Permanent Dipole Magnet for Future Light Sources

permanent-magnet, dipole, operation, emittance

1253

T. Watanabe, K. Fukami, T. Nakanishi, S. Sasaki
JASRI/SPring-8, Hyogo, Japan

Permanent dipole magnets with variable magnetic field have been designed, fabricated, and tested at SPring-8. Permanent magnets can be advantageous over electromagnets in terms of reliability, stability and compactness in addition to the small power consumption. No unexpected down of an accelerator due to power supply failure is supposed to happen. There is no cooling water flow that can induce a fluctuation of the magnetic field. These features may become important for future light sources, where a very reliable, stable, and compact ring is required. In addition, the power consumption is now one of the most important issues after the 3.11 disaster in Japan. One of critical issues to realize such a magnet is that a magnetic field has to be tuned. In the future, combined-functioned and longitudinally gradient magnets will play a key role in achieving extremely small emittance. In such a case, changing a gap will not work any more. We have designed and fabricated a permanent dipole magnet of which magnetic field can be tuned without changing the gap. The results of the performance test will be presented and a possibility to apply it for future light sources will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO093

Numerical Study of Intrinsic Ripples in J-PARC Main-ring Magnets

damping, operation, synchrotron, acceleration

1256

Y. Shirakabe, A.Y. Molodozhentsev, M. Muto
KEK, Tsukuba, Japan

Beam ripples are one of the critical problems in high power proton synchrotrons. Magnet field ripples are considered as a main origin of the beam ripples among various possible sources. Although magnet power supply ripples are generally treated as the dominating ripple source, the load circuit parameters of the magnets and their interconnections are also playing critical roles in defining the ripple amplitudes and frequencies. In this viewpoint, the magnet power supplies are treated as simplified current sources, and the ripples generated in the circuit systems are investigated both in analytical and numerical ways. One of the findings in this direction of investigation is the existence of intrinsic ripples. The intrinsic ripples occur inevitably in the synchrotron magnets, no matter how the power supplies are producing idealistic current ramp patterns. Their amplitudes are defined by the circuit parameters such as inductance and capacitance, and the ramp parameters such as ramp rates. Some of the analytical mechanisms in generating the magnet field ripples are presented as well as the studied examples.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO099

Development of a Method for Measuring the Radial Component of the Magnetic Field in AVF Cyclotrons

cyclotron, experiment, proton, extraction

1274

N.A. Morozov, G.A. Karamysheva, S.A. Kostromin, E. Samsonov, N.G. Shakun, E. Syresin
JINR, Dubna, Moscow Region, Russia

In AVF cyclotrons the median plane of the magnetic field rather often does not coincide with the mid-plane of their magnetic system. To measure the radial component of the magnetic field, equipment based on search coils is developed and used to correct the median plane of the magnetic field. The equipment for Br mapping is described. The Br mapping and shimming results are presented for two proton therapy IBA C230 cyclotrons.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO099

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO100

Rare-Earth End Magnets of a Miniature Race-Track Microtron and their Tuning

microtron, linac, quadrupole, permanent-magnet

1277

I.Yu. Vladimirov, N.I. Pakhomov, V.I. Shvedunov
MSU, Moscow, Russia
Yu.A. Kubyshin
UPC, Barcelona, Spain
J.P. Rigla
I3M, Valencia, Spain
V.V. Zakharov
Tehnomag ltd., Kaluga, Russia

We report on the tuning of end magnets of a compact 12 MeV racetrack microtron (RTM) which is under construction at the Technical University of Catalonia. They are magnetic systems composed of four dipoles with the Rare-Earth Permanent Magnet (REPM) material used as a source of the magnetic field. The poles of the magnets are equipped with tuning plungers which allow to adjust the magnetic field level. In the article we describe the tuning procedure and different techniques that were used in order to fulfill strict requirements of the field characteristics of the end magnets. It is shown that the obtained magnetic systems provide correct beam trajectories in the 12 MeV RTM.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO100

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO101

Fast Kicker

kicker, impedance, vacuum

1280

V.V. Gambaryan, A.A. Starostenko
BINP SB RAS, Novosibirsk, Russia

Pulsed deflecting magnet project was worked out in BINP. The kicker design task is: impulsive force value is 1 mT*m, pulse edge is 5 ns, and impulse duration is about 200 ns. The unconventional approach to kicker design was offered. The possibility for set of wires using instead of plates using is considered. This approach allows us to reduce the effective plate surface. In this case we can decrease effects related to induced charges and currents. In the result of modelling optimal construction was developed. It includes 6 wires. The magnet aperture is about 5 cm. Calculated field rise time (about 1.5 ns) satisfies the conditions. Induced current effect reducing idea was confirmed. For configuration with 3 wires pair (with cross section of 2 mm) induced current in one wire is about 10% and in the wall is about 40%. However for design with plates current is about 40% and 20% respectively. Obtained magnet construction allows controlling of high field homogeneity by changing currents magnitudes in wires. In general we demonstrated the method of field optimization. Summary. Optimal kicker design was obtained. Wires using idea was substantiated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO101

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO105

Design of the Main Magnets of the SESAME Storage Ring

quadrupole, sextupole, dipole, storage-ring

1292

A. Milanese
CERN, Geneva, Switzerland
E. Huttel, M.M. Shehab
SESAME, Allan, Jordan

Funding: This work is partially supported by the EC under the CESSAMag project, FP7 contract 338602.
The lattice of the SESAME storage ring includes 16 combined function dipoles, 32 focusing quadrupoles, 32 defocusing quadrupoles, 32 focusing sextupoles and 32 defocusing sextupoles. Vertical / horizontal dipoles and skew quadrupole correctors are embedded in each sextupole. This paper summarizes the magnetic design and gives the parameters for all these magnets. The pole tip profile is commented and results of simulations are presented. At the end, the status of the procurement in the industry and collaborating institutes is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO105

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO106

Status of the ELENA Magnet System

quadrupole, dipole, operation, antiproton

1295

D. Schoerling
CERN, Geneva, Switzerland

ELENA, the Extra Low ENergy Antiproton ring, will be a CERN facility with the purpose to deliver antiprotons at lowest energies aiming to enhance the study of antimatter. It will be a hexagonal shaped ring with a circumference of about 30 m decelerating antiprotons from energies of 5.3 MeV to 100 keV. Due to the extra-low beam rigidity the design of the magnet system is especially challenging because even small fields, for example arising from residual magnetization and hysteresis, will have a major impact both on the beam trajectory and beam dynamics. In this paper the design approach for such an extra-low beam rigidity magnet system is presented. The main challenges are outlined and solutions for the design of the magnet system are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO106

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO107

Prediction of the Field Distribution in CERN-PS Magnets

resonance, synchrotron, vacuum, injection

1298

D. Schoerling
CERN, Geneva, Switzerland

The CERN Proton Synchrotron (PS) has a circumference of 628 m and operates at an energy of up to 26 GeV. It uses one hundred combined function magnets, with pole shapes designed to create a dipolar and a quadrupolar field component. Each magnet is equipped with a main current circuit and five auxiliary current-circuits, which allows controlling the linear and non-linear magnetic fields. These magnets were installed in the 1950s, and part of the compensating circuits have been added or modified since then, resulting in the fact that detailed measurements of the field distribution in each individual magnet as a function of the six currents are not available. This study is performed to estimate, through deterministic and stochastic calculations, the expected mean value and standard deviation of the field harmonics of the installed magnets as input for beam dynamics simulations. The relevant results can be used to design correction schemes to minimise beam losses in the PS and to enable the acceleration of higher brightness beams required to reach the foreseen Large Hadron Collider (LHC) luminosity targets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO107

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO108

Design and Performance of the TPS DC Septum Magnet

septum, shielding, booster, electron

1301

C.S. Yang, C.-H. Chang, Y.L. Chu, T.Y. Chung, C.-S. Hwang, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

To decrease the loading on an AC septum magnet, a DC septum magnet was fabricated and applied to the extraction system of the booster ring at Taiwan Photon Source (TPS). The minimal gap is 16.44 mm; the core length is 800 mm and the pole width is 45 mm. The maximum peak field of the DC septum magnet is designed to be 0.95 T at 12 kA with 24-turn coils. The maximum bending angle of the electron beam passing through the septum magnet is 75.5 mrad. Because the electron beam would be perturbed by the leakage field from the septum magnet, shielding between the septum magnet and the booster ring is an important issue for the operation of the beam. Here we report the shielding method with two materials of the DC septum magnet, and discuss the field mapping and shielding from the leakage field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO108

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO110

Analytic Methods of Simulating Magnetic Fields for the Taiwan Photon Source

dipole, multipole, software, photon

1307

C.Y. Kuo, C.-H. Chang, C.-S. Hwang, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

Analytic methods of four kinds served for analysis of the magnetic field of TPS magnets that were simulated with OPERA 2D and 3D software. These analytic methods include fast Fourier transform, one-dimensional fitting, two-dimensional circular or elliptic fitting and a differential field. In this paper we discuss the precision of varied analytic methods for properties of a magnetic field in various situations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO110

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO112

Transient Magnetodynamic Finite Element Analysis of the ISIS M25/2 10Hz Kicker Magnet

flattop, kicker, target, proton

1313

T.B.J. Mouille
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

In 2007 a second target station (TS2) was added to the ISIS pulsed neutron source at RAL. Two slow kicker magnets are operated in order to direct a 10Hz proton beam toward TS2 through the TS2 Extract Proton Beam line (EPB2). When first manufactured and tested, the M25/2 exhibited an unforeseen magnetic and thermal behaviour. It was quickly identified that this was caused by the eddy currents induced in the laminated core and the mechanical structure of the magnet. Corrective actions were taken to counterbalance their effects but no further analysis was performed at the time. Recent developments in hardware and software make this analysis more feasible. In this paper we present the results of the transient magnetodynamic simulation that was set up in order to model these eddy currents and study their impact on the M25/2 field quality.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO112

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO115

Progress on the Dipole Magnet for a Rapid Cycling Synchrotron

dipole, synchrotron, magnet-design, feedback

1322

H. Witte, J.S. Berg
BNL, Upton, Long Island, New York, USA
M.L. Lopes
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A rapid cycling hybrid synchrotron has been proposed for the acceleration of muons from 375 to 750 GeV. The bending in a hybrid synchrotron is created with interleaved cold and warm dipoles; the warm dipoles modulate the average bending field for the different particle momenta. A key challenge for the warm dipole magnets is the ramp rate, which is equivalent to frequencies of 400-1000 Hz. Recently a design has been suggested which employs 6.5 Si steel for the return yoke and FeCo for the poles. In simulations the design has shown a good performance (up to 2T) due to the FeCo and acceptable power losses by employing SiFe with a high Si content. The paper discusses the effect of eddy currents induced in the laminations and hysteresis effects on the field quality.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO115

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME003

Effect of CSR Shielding in the Compact Linear Collider

shielding, radiation, electron, synchrotron

1337

J. Esberg, R. Apsimon, A. Latina, D. Schulte
CERN, Geneva, Switzerland

The Drive Beam complex of the Compact LInear Collider must use short bunches with a large charge making beam transport susceptible to unwanted effects of Coherent Synchrotron Radiation emitted in the dipole magnets. We here present the effects of transporting the beam within a limited aperture which decreases the magnitude of the CSR wake. The effect, known as CSR shielding, eases the design of key components of the facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME010

The Physics Programme of next MICE Step IV

emittance, scattering, factory, experiment

1361

J.C. Nugent
University of Glasgow, Glasgow, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy

Funding: DOE, NSF, STFC, INFN, CHIPP and several others
The International Muon Ionization Cooling Experiment is progressing towards a full demonstration of the feasibility of ionization cooling technology decisive for neutrino physics and muon colliders. Step IV should provide the first precise measurements of emittances and first evidence of cooling. The components required for Step IV, including spectrometer solenoids, muon trackers and absorber-FC (focus coil) modules have been assembled with data collection expected in 2015. The physics programme of this Step will be described in detail, with LiH and a few other promising absorber materials of different shapes.
Abstract presented by the chair of the speaker bureau of the MICE collaboration, that would next select a MICE member to prepare and present the poster

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME015

Study Cooling Performance in a Helical Cooling Channel for Muon Colliders

emittance, solenoid, collider, plasma

1376

K. Yonehara
Fermilab, Batavia, Illinois, USA

The cooling performance in a six-dimensional helical muon beam cooling channel (HCC) has been studied in various beam lattice parameters. We show that the HCC works with a practical beam parameter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME016

Status of the Complete Muon Cooling Channel Design and Simulations

emittance, solenoid, collider, luminosity

1379

C.Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson, S.A. Kahn, F. Marhauser
Muons, Inc, Illinois, USA
Y.I. Alexahin, D.V. Neuffer, K. Yonehara
Fermilab, Batavia, Illinois, USA
Y.S. Derbenev, V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA

Funding: Work supported in part by DOE STTR grant DE-SC 0007634.
Muon colliders could provide the most sensitive measurement of the Higgs mass and return the US back to the Energy Frontier. Central to the capabilities of such muon colliders are the cooling channels that provide the extraordinary reduction in emittance required for the precise Higgs mass measurement and increased luminosity for enhanced discovery potential of an Energy Frontier Machine. We present the status of the design and simulation of a complete muon cooling channel that is based on the Helical Cooling Channel (HCC), which operates via continuous emittance exchange to enable the most efficient design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME017

Design and Simulation of a Matching System into the Helical Cooling Channel

solenoid, emittance, collider, operation

1382

C.Y. Yoshikawa
MuPlus, Inc., Newport News, Virginia, USA
Y.I. Alexahin, D.V. Neuffer, K. Yonehara
Fermilab, Batavia, Illinois, USA
C.M. Ankenbrandt, R.P. Johnson, S.A. Kahn, F. Marhauser
Muons, Inc, Illinois, USA
Y.S. Derbenev, V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA

Funding: Work supported in part by DOE STTR grant DE-SC 0007634.
Muon colliders could provide the most sensitive measurement of the Higgs mass and return the US back to the Energy Frontier. Central to the capabilities of muon colliders are the cooling channels that provide the extraordinary reduction in emittance required for the precise Higgs mass measurement and increased luminosity for enhanced discovery potential of an Energy Frontier Machine. The Helical Cooling Channel (HCC) is able to achieve such emittance reduction and matching sections within the HCC have been successfully designed in the past with lossless transmission and no emittance growth. However, matching into the HCC from a straight solenoid poses a challenge, since a large emittance beam must cross transition. We elucidate on the challenge and present evaluations of two solutions, along with concepts to integrate the operations of a Charge Separator and match into the HCC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME019

Design and Simulation of a High Field - low energy Muon Ionization Cooling Channel

emittance, focusing, solenoid, scattering

1386

H. K. Sayed, J.S. Berg, R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA

Muon beams are generated with inherited large transverse and longitudinal emittances. In order to achieve low emittance within the short lifetime of the muons, the only feasible cooling scheme is the ionization cooling. In this study we present a design and simulation of a novel ionization cooling channel. The channel operates at a very strong magnetic fields of 25-30 T with low muon beam energy starting from 66 MeV and decreasing gradually. We study the beam dynamics of such low energy beam in high field region inside and between cooling stages. Key design parameters will be presented and in addition the performance and channel requirements of RF cavities and high field magnets will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME022

Design and Optimization of a Particle Selection System for Muon based Accelerators

proton, solenoid, target, factory

1395

D. Stratakis, J.S. Berg
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In Muon Accelerators muons are produced by impacting high energy protons onto a target to produce pions. The pions decay to muons which are then accelerated. Through this process a significant background of protons and electrons are generated, which may result in heat deposition on superconducting materials and activation of the machine. In this paper we propose a two-step particle selection scheme: a chicane to remove the high momentum particles from the beam and a Beryllium block absorber that reduces momentum of all particles in the beam, resulting in the loss of low momentum protons. We review the design and numerically examine its impact on the performance of the muon front-end.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME024

A hybrid six-dimensional muon cooling channel with gas filled cavities

emittance, vacuum, cavity, lattice

1401

D. Stratakis
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Obtaining the desired micron-scale emittances for a Muon Collider requires transporting the muon beam through long sections of a beam channel containing rf cavities, absorbers, and focusing solenoids. Here we discuss possible implementation of high-pressure gas-filled RF cavities in a 6D ionization cooling channel and some technical issues associated with it. The key idea of our scheme is a hybrid approach that uses high-pressure gas to avoid cavity breakdown, along with discrete LiH absorbers to provide the majority of the energy loss. We show that the channel performs as well as the original vacuum rf channel while potentially avoiding degradation in rf gradient associated with the strong magnetic field in the cooling channel.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME026

TMCI Thresholds for LHC Single Bunches in the CERN-SPS and Comparison with Simulations

optics, impedance, emittance, kicker

1407

H. Bartosik, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, C. Zannini
CERN, Geneva, Switzerland

At the beginning of 2013 an extensive measurement campaign was carried out at the SPS in order to determine the Transverse Mode Coupling Instability thresholds of LHC-type bunches in a wide range of intensities and longitudinal emittances. The measurements were performed in two different configurations of machine optics (nominal and low gamma transition) with the goal to characterize the differences in behavior and performance. The purpose of this paper is to describe in detail the measurement procedure and results, as well as the comparison of the experimental data with HEADTAIL simulations based on the latest SPS impedance model. Beside the impedances of the resistive wall, the beam position monitors (BPMs), the RF cavities, and the flanges, an advanced model of the impedance of the kicker magnets is included, which are found to play a major role in the definition of the stability region of the LHC-type bunches in the two optics configurations studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME029

Identification of High-frequency Resonant Impedance in the CERN SPS

impedance, vacuum, damping, resonance

1416

E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, J.V. Campelo, F. Caspers, J. F. Esteban Müller, A. Lasheen, B. Salvant, H. Timko
CERN, Geneva, Switzerland

The spectrum of long bunches injected into the ring with RF switched off has been used in the SPS in the past to probe the longitudinal coupling impedance. After a large campaign of shielding of 800 inter-magnet vacuum ports in 1999 - 2001, the microwave instability threshold was significantly increased and the high-frequency spectrum of the beam became practically flat, apart from a prominent peak at around 1.4 GHz. As corresponding high-frequency impedance could potentially lead to microwave instability of high intensity bunches observed now at high energies in the SPS, a search of the source of this impedance was launched. Using a combination of impedance simulations and measurements, vacuum flanges that are present in a large quantity in the machine have been identified as a main source of impedance at this frequency. Particle simulations based on the SPS impedance model, which includes this previously unknown impedance, are able to reproduce the characteristics of the bunch spectrum and amplitude growth rates and hence, confirm that the impedance of the vacuum flanges is responsible for the observed spectral peak.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME031

Radiation Pressure Acceleration and Transport Methods

laser, plasma, acceleration, target

1422

P. Schmidt, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim, O. Boine-Frankenheim, I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
HIJ, Jena, Germany
I. Hofmann
IAP, Frankfurt am Main, Germany

Funding: HGS-HIRe for FAIR, HIC for FAIR, Technische Universität Darmstadt, FB 18 TEMF
Several projects worldwide such as LIGHT at GSI focus on laser ion acceleration. With the development of new laser systems and advances in the target production a new acceleration mechanism has become of interest: The Radiation Pressure Acceleration (RPA). An ultra short high intense laser pulse hits a very thin foil target and the emerging plasma is ideally accelerated as one piece (light sail regime). The ions reach kinetic energies up to GeV and nearly solid body densities. In this work, the distribution and transport of a RPA plasma is studied. 1D and 2D PIC simulations (software: VSim) are carried out to obtain the phase space distribution of the plasma. The results are compared to fluid models (software: FiPy and USim). A reference model an RPA plasma is obtained which is then used for advanced transport studies. Transport mechanisms (active and passive) are studied, such asμlenses and foil stacks.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME035

Design Study of the Laser-driven Dielectric Accelerator

laser, electron, acceleration, focusing

1428

K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Otsuki
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
Laser driven dielectric accelerators (LDA) are vigorously studied in order to apply to various fields in recent years. Characteristics of the LDA output such as sub-micron diameter, atto-second bunch and high acceleration field are suitable for in-situ investigating the biological effects of low doses of radiation in a living cell. The output energy of 1 MeV is sufficient for sniping a cell nucleus or DNA. Although the electronic charge in the bunch is in the order of 10 fC, the tightly focused beam enable to cause a local damage in the cell. We have reported optimum structure parameters of dielectric in the nonrelativistic regime. The low acceleration efficiency of slow electrons by short laser pulses is the serious problem. The accelerator length, laser intensity, pulse width, and optical system must be adjusted to design the practical LDA. We present the design principle of the LDA for nonrelativistic electrons and present status of the pumping laser of us.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME036

Simulation Study on Electron Beam Acceleration using Coherent Cherenkov Radiation

electron, acceleration, radiation, laser

1431

K. Kan, M. Gohdo, T. Kondoh, K. Norizawa, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan
M. Hangyo
ILE Osaka, Suita, Japan
R. Kuroda, H. Toyokawa
AIST, Tsukuba, Ibaraki, Japan

Beam diagnostics for electron bunch length using spectrum analysis of multimode terahertz (THz) -wave have been studied in ISIR, Osaka University*. The multimode THz-wave was generated by coherent Cherenkov radiation (CCR)** using hollow dielectric tubes and femtosecond/picosecond electron bunches. In this study, numerical calculation of acceleration and deceleration of electron beam using multimode THz-wave was carried out.
* K. Kan et al., Appl. Phys. Lett. 99, 231503 (2011).
** A. M. Cook et al., Phys. Rev. Lett. 103, 095003 (2009).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME037

Development on On-chip Radiation Source using Dielectric Laser Accelerator

laser, electron, acceleration, radiation

1434

S. Otsuki
The University of Tokyo, Tokyo, Japan
K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
S. Mima
RIKEN, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was partly supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120.
One of the state-of-the-art acceleration schemes, where high intensity laser pulses are modulated by dielectric grating structure such as quartz to accelerate charged particles, is dielectric laser acceleration (DLA)*. The difference of our DLA concept from other schemes is installation of a prism: the tilted wave-front in a prism shape refractive medium leads the suitable delay to match the phase advance of the electron beam. We plan to apply this method to build an on-chip radiation source which can hit and damage target elements of the cells. Such an application is useful in radiation biology, i.e., for investigation on bystander effects. The x-rays with small radius and adequate intensity required for this goal can be obtained using sub-micron beams from the small accelerating structure at high repetition rate (such as 50 kHz). In addition, the mass productivity of the DLA based on the consumer-grade laser and the photolithography has advantage compared to the conventional RF accelerator using high power klystrons. We will present field simulation and preliminary experimental results for demonstration on our concept of DLA.
* Demonstration of electron acceleration in a laser-driven dielectric microstructure, Nature 2013
** Laser-Based Acceleration of Nonrelativistic Electrons at a Dielectric Structure, Phys. Rev. 2013

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME038

Wakefield excitation via a metasurface-loaded waveguide

impedance, wakefield, coupling, radiation

1437

E. Sharples
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Letizia
Lancaster University, Lancaster, United Kingdom

Funding: Work supported by STFC Quota Studentship grant ST/K520133/1
A metallic waveguide loaded with layers of complementary split ring resonator (CSRR) based metasurface is presented for accelerator and coherent source applications. This structure presents left handed behaviour arising from the strong electrical response of CSRRs which form the metasurface and the transverse field confined between the closely positioned metasurface layers. The loaded waveguide structure is known to have a TM-like mode at 5.47GHz suitable for acceleration. In this paper, the results of wakefield simulations are presented and a narrow band excitation identified around the frequency of the TM-like mode, indicating strong coupling between the beam and the field of this mode.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME040

Drive Beam Break-up Control and Practical Gradient Limitation in Collinear Dielectric Wakefield Accelerators

wakefield, acceleration, linac, quadrupole

1443

C. Li, W. Gai, J.G. Power, A. Zholents
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
C. Li, C.-X. Tang
TUB, Beijing, People's Republic of China

Dielectric wakefield accelerator (DWA) concept has gained significant attention for the need of the future large scale facilities. For a practical machine, one needs to overcome a major challenge for the DWA that is the efficient energy extraction and stable propagation at the same time for the drive beam. Typically, a slightly off axis beam become unstable in the dielectric channel due to transverse wakefield excitation, that could be controlled if a strong external alternating magnetic focusing channel applied at the same time. However, there is limitation on the practical magnetic field in the focusing channel (typically < 1 Tesla), thus imposing operating point for the DWA. In this article, we explore the operating point of the DWA for various structure frequencies and drive beam charge, particularly on the gradient and total acceleration distance, and provide guidance on the DWA design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME046

3-D Particle-in-cell Simulations for Quasi-phase Matched Direct Laser Electron Acceleration in Density-modulated Plasma Waveguides

electron, laser, plasma, emittance

1463

M.W. Lin
The Pennsylvania State University, University Park, Pennsylvania, USA
I. Jovanovic
Penn State University, University Park, Pennsylvania, USA

Funding: This work is supported by the Defense Threat Reduction Agency through contract HDTRA1-10-1-0034.
Quasi-phase matched (QPM) direct laser acceleration (DLA) of electrons can be realized with guided, radially polarized laser pulses in density-modulated plasma waveguides*,**. A 3-D particle-in-cell (PIC) simulation model has been developed to study the scheme in which an electron bunch from a laser wakefield accelerator (LWFA) is injected into a plasma waveguide for the second-stage DLA to higher energies. In addition to being driven directly by the laser field, the electrons also experience the laser pondermotive force and the electrostatic force from the excited plasma waves. The results lead to better understanding of the interactions between the electron bunch, the laser pulse and the background plasma. Selected bunch lengths, bunch sizes and time delays with respect to the laser pulse are assigned for the injected electrons in a series of simulations. The energy spectrum and emittance of the accelerated electron bunch vary depending on those initial conditions, and they can be chosen to optimize the DLA performance.
* P. Serafim, et al., IEEE Trans. Plasma Sci. 28, 1155 (2000).
** M. -W. Lin and I. Jovanovic, Phys. Plasmas 19, 113104 (2012).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME056

Improving Ion and Electron Beam Characteristics within LA³NET

laser, electron, acceleration, photon

1495

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191.
Lasers are widely used at accelerator and light source facilities for beam generation, acceleration and optimization. Research within LA³NET focuses on laser-based particle sources (photo injectors and laser ion sources), laser acceleration, and laser-based beam diagnostics. This project was recently selected as a ‘success story’ by the European Commission for its research achievements. This paper presents selected numerical and experimental results. From HZDR results of electron transport simulations in their new SRF gun II cavity, super-conductive solenoid and downstream accelerators are shown. The results from optimization studies into asymmetric grating structures obtained at the University of Liverpool are also presented, along with initial results from studies into novel diagnostics for high intensity proton beams at CERN and low energy electron beams at KIT. Finally, the events organized by the consortium to date and future plans are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME057

Optimization of Accelerators and Light Sources within oPAC

network, cavity, controls, booster

1499

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289485.
The optimization of particle accelerators and light sources by combining studies into beam physics, instrumentation, numerical simulations and accelerator control systems is the aim of the EU-funded oPAC project. With a budget of more than 6 M€, oPAC is one of the largest training networks ever funded by the EU and currently trains more than 20 Marie Curie Fellows. This paper presents selected research highlights, including optimization studies into the CERN Proton Synchrotron (PS), measurement and correction of linear and nonlinear optics distortions in the ALBA synchrotron (Spain), perturbation measurements of a cavity Schottky noise detector at GSI (Germany) and R&D into device control data base tool at COSYLAB (Slovenia). Moreover, a summary of past and future oPAC events is also given.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME060

Simulation Analysis on Micro-Bunched Density Modulation from a Slit-Masked Chicane

electron, bunching, acceleration, dipole

1509

Y.-M. Shin, P. Piot, C.R. Prokop
Northern Illinois University, DeKalb, Illinois, USA
D.R. Broemmelsiek, E.R. Harms, A.H. Lumpkin, J. Ruan, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Pre-bunching a beam at a resonance condition with an accelerating structure vastly improves performance of beam-driven accelerators and undulators since it enhances a beam-wave coupling. We plan to test a slit-mask micro-buncher at the chicane of Fermilab-ASTA 50 MeV beamline in the effort of advanced accelerator research. With the chicane design parameters (bending angle (alpha) of 18 degree, R56 ~ - 0.18 m, and bending radius of ~ 0.78 m), analytic model showed that a slit-mask with W (period) = 900 um and a (aperture width) = 300 um (30 % transparency) generates 100 um spaced micro-bunches with 5 ~ 6 % correlated energy spread. Two kinds of combined beamline simulation, CST-PS+Impact-Z and Elegant+Shower, including space charge and CSR effects, showed that a 900 um spaced, 300 um wide slits placed in the middle of chicane splits 20 pC – 1 nC bunches into ~ 100 um spaced micro-bunches. It is possible that a further optimization of mask design creates sub-100 fs micro-bunches, which is currently under development.
*[1] NIM A 375, 597 (1996)
[2] PRL 101, 054801 (2008)
[3] Y.-E Sun, P. R. G. Piot, FEMILAB-CONF-08-408-APC
** ASTA: Advanced Superconducting Test Accelerator

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME064

Laser-driven Acceleration with External Injection at SINBAD

plasma, laser, injection, acceleration

1515

J. Grebenyuk, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany

One of the important milestones to make plasma acceleration a realistic technology for user-applications is demonstration of bunch acceleration inside a plasma wake with minimal degradation of its quality. This can be achieved by external injection of beams into a plasma accelerator. SINBAD is a proposed dedicated accelerator research and development facility at DESY where amongst other topics laser-driven wakefield acceleration with external injection of ultra-short bunches will be exploited. To minimise energy-spread growth the bunch should occupy a small fraction of the plasma wavelength. In addition it has to be longitudinally synchronised with the laser driver to high accuracy. To avoid emittance growth the beam Twiss parameters have to be matched to the intrinsic beta-function of the plasma. To facilitate matching and synchronisation, acceleration at low plasma densities can be advantageous. We present a preparatory feasibility study for future plasma experiments at SINBAD using simulations with the particle-in-cell code OSIRIS. Field-gradient scaling laws are presented together with parameter scans of externally injected bunch, such as its injection phase, charge and length.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME075

Simulations on Laser Wakefield Generation in a Parabolic Magnetic-plasma Channel

plasma, laser, wakefield, electron

1528

D.N. Gupta, M. Singh
University of Delhi, Delhi, India
D. Jang, H. Suk
APRI-GIST, Gwangju, Republic of Korea
B.S. Sharma
Kota University, Rajasthan, India

To utilize the laser-plasma channel for laser wakefield acceleration, we have studied the non-paraxial theory of nonlinear propagation of ultra-intense relativistic Gaussian laser pulse in a preformed spatially tapered magneto-plasma channel having a parabolic density profile. A three-dimensional envelope equation for the laser field is derived, which includes the non-paraxial and applied magnetic field effects. An analytical expression for the wakefield is derived and analyzed the results with the help of particle-in-cell (PIC) simulations. It is shown that wakefield structures and the phase of axial component of the wakefield depend on applied external magnetic field. This aspect of theoretical observation can be used in the production of highly collimated mono-energetic x-rays.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME075

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME076

Numerical modeling of the E-209 self-modulation experiment at SLAC - FACET

plasma, electron, wakefield, experiment

1531

L.D. Amorim, L.O. Silva, J. Vieira
IPFN, Lisbon, Portugal
P. Muggli
MPI, Muenchen, Germany

The E-209 experiment currently running at SLAC- FACET used a long electron bunch (∼ 5 times the plasma wavelength) to drive plasma wakefields through the self- modulation instability. In this work we present and analyze numerical simulation results performed with the particle-in- cell (PIC) code OSIRIS. The results show that SMI saturates after 5cm of propagation in the plasma and that the maxi- mum acceleration wakefields, 15 − 20GV/m, are sustained over a 1m long plasma. Electron bunch energy loss of 4GeV was observed in the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME076

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME079

A Spectrometer for Proton Driven Plasma Wakefield Accelerated Electrons at AWAKE

electron, plasma, proton, wakefield

1540

S. Jolly, L.C. Deacon, J.A. Goodhand, S.R. Mandry, M. Wing
UCL, London, United Kingdom
S.R. Mandry
MPI, Muenchen, Germany

The AWAKE experiment is to be constructed at the CERN Neutrinos to Gran Sasso facility (CNGS). This will be the first experiment to demonstrate electron acceleration by use of a proton driven plasma wakefield. The 400 GeV proton beam from the CERN SPS will excite a wakefield in a plasma cell several metres in length. To observe the plasma wakefield, electrons of a few MeV will be injected into the wakefield following the head of the proton beam. Simulations indicate that electrons will be accelerated to GeV energies by the plasma wakefield. The AWAKE spectrometer is intended to measure both the peak energy and energy spread of these accelerated electrons. The baseline design makes use of a single dipole magnet to separate the electrons from the proton beam. The dispersed electron beam then impacts on a scintillator screen: the resulting scintillation light is collected and recorded by an intensified CCD camera. The design of the spectrometer is detailed with a focus on the scintillator screen. Results of simulations to optimise the scintillator are presented, including studies of the standard GadOx scintillators commonly used for imaging electrons in plasma wakefield experiments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME079

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPME081

Plasma Wakefield Acceleration at CLARA PARS

plasma, wakefield, accelerating-gradient, electron

1544

K. Hanahoe, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, J.A. Clarke, J.K. Jones, J.W. McKenzie, B.L. Militsyn, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.A. Clarke, J.K. Jones, J.W. McKenzie, Y. Wei, C.P. Welsch, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B. Hidding
USTRAT/SUPA, Glasgow, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom
Y. Wei, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

PARS is a proposed Plasma Accelerator Research Station using the planned CLARA (Compact Linear Accelerator for Research and Applications) electron linear accelerator at Daresbury Laboratory in the UK. In this paper, two- dimensional particle-in-cell simulations based on realistic CLARA beam parameters are presented. The results show that an accelerating gradient of 2.0 GV/m can be achieved over an accelerating length of at least 13 cm. Preliminary simulation results for a two bunch scheme show an energy gain of 70% over a length of 13 cm, giving an average accelerating gradient of 1.2 GeV/m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME081

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI001

ESSnuSB: A New Facility Concept for the Production of Very Intense Neutrino Beams in Europe

proton, linac, target, detector

1550

E. Bouquerel, E. Baussan, M. Dracos, F.R. Osswald, P. Poussot, N. Vassilopoulos
IPHC, Strasbourg Cedex 2, France

A new project for the production of a very intense neutrino beam has arisen to enable the discovery of leptonic CP violation and neutrino mass hierarchy. This facility will use the proton linac of the European Spallation Source (ESS) in Lund to deliver the neutrino super beam. The ESS linac is expected to be fully operational at 5 MW power by 2022, producing 2 GeV and 2.86 ms long proton pulses at a rate of 14 Hz. An upgrade of the power to 10 MW and a frequency of 28 Hz, in which half is for the neutron beam, is necessary for the production of the neutrino beam. The primary proton beam-line completing the linac will consist of switchyards and accumulator rings. The secondary beam-line producing neutrinos will consist of a four-horn/target station, decay tunnel and beam dump. A megaton scale water Cherenkov detector will be located at a baseline of about 500 km in one of the existing mines in Sweden and it will measure the neutrino oscillations. The elements of the primary and secondary beam-lines and all the possible scenarios impacting the design of the ESSnuSB facility as well as the safety issues due to the high irradiation produced are presented and discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI003

Simulating the Production and Eﬀects of Dark Currents in MICE Steps V and VI

electron, cavity, solenoid, experiment

1556

C. Hunt, J. Pasternak, M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: STFC
The completion of the international Muon Ionisation Cooling Experiment (MICE) Step V will involve the construction, commissioning and use of RF cavity and Coupling Coil (RFCC) Modules. The RFCCs consist of 4 RF cavities and a solenoid magnet, and are expected to act as a source of potentially damaging electrons (dark currents) and X-rays. Ongoing work to create a high-statistics simulation of the dark current production, within RF cavities, is described. Current results predict the energy and angular spectra of emitted electrons for an RFCC, and include particle tracking, realistic field maps and ionisation energy losses in cavity windows. Individual electron emitters, parametrised by the Fowler-Nordheim equation, are used and are user-definable, allowing potential worst-case scenarios to be simulated and upper/lower limits for the total dark current to be estimated. These data are being used within the MICE Analysis and User Software (MAUS) to estimate the potential detector backgrounds and the damage that may be inflicted upon the scintillating fibre trackers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI005

nuSTORM Horn Optimization Study

target, optics, proton, controls

1562

A. Liu, A.D. Bross, D.V. Neuffer
Fermilab, Batavia, Illinois, USA

The efficiency of using magnetic horns as a pion collection device has been recognized by several neutrino projects. In the study, we began with a “NuMI-like” horn, which was applied to collect the secondary pions from bombarding the target with 120 GeV/c protons in the nuSTORM proposal. The necessity of optimizing the horn for a non-conventional neutrino beamline like the nuSTORM pion beamline was then acknowledged. This paper presents a detailed description of the optimization objectives, the Multi-objective Genetic Algorithm developed for this specific purpose, and the results of the optimization. With the full G4beamline simulation results, the success of the optimization provides an increase of 16\% in the useful muons in the ring. This methodology can be applied to any neutrino beamline configuration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI005

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI017

Artificial Collisions, Entropy and Emittance Growth in Computer Simulations of Intense Beams

emittance, space-charge, focusing, scattering

1588

O. Boine-Frankenheim, I. Hofmann, J. Struckmeier
GSI, Darmstadt, Germany

During particle tracking with self-consistent space charge artificial collision between the macro-particles lead to diffusion-like, numerical effects. The artificial collisions generate a stochastic noise spectrum. As a consequence the entropy and the emittance of the particle beam can growth along periodic focusing structures. The growth rates depend on the number of simulation macro-particles and on the space charge tune shifts. For long-term tracking studies the numerical diffusion can lead to incorrect beam loss predictions. In our study we present analytical prediction for the numerical friction and diffusion in 2D and 3D simulations. For simple focusing structures with derive a relation between the friction coefficient and the entropy growth. The scaling of the friction coefficient with the macro-particle number and the space charge tune shift is obtained from 2D and 3D simulations and compared to the analytic predictions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI019

Incoherent and Coherent Effects of Space Charge Limited Electron Clouds

electron, wakefield, space-charge, dipole

1594

F.B. Petrov, O. Boine-Frankenheim, O.S. Haas
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: Work is supported by the BMBF under contract 05H12RD7.
Recent studies show that the space charge limited (saturated) electron cloud generated by relativistic bunches has strongly inhomogeneous distribution. In particular, a dense electron sheath is formed near the pipe wall. This feature modifies the stopping powers and the microwave transmission compared with the uniform cloud case. In this paper we investigate further the influence of the space charge limited electron cloud on relativistic bunches. In particular, we focus on the incoherent tune spread and compare the results with the homogeneous cloud case. We derive analytical expressions governing the pinch dynamics of the saturated cloud in round geometry. The contribution of the electron cloud sheath to the wake fields is investigated as well. Findings of the analytical theory are then successfully compared with numerical particle-in-cell simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI020

Study of Electron Cloud Effects in SuperKEKB

electron, emittance, damping, radiation

1597

K. Ohmi, D. Zhou
KEK, Ibaraki, Japan

In SuperKEKB, high beta section exists in the interaction region. Fast head-tail instability and incoherent emittance growth due to electron cloud are enhanced in the high beta section. Especially high beta sections are located every betatron phase advance pi. Nonlinear force due to electron cloud is coherently accumulated. Incoherent eminence growth dominates.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI021

Impedance Calculation and Simulation of Microwave Instability for the Main Rings of SuperKEKB

impedance, cavity, vacuum, kicker

1600

D. Zhou, T. Abe, T. Ishibashi, Y. Morita, K. Ohmi, K. Shibata, Y. Suetsugu, M. Tobiyama
KEK, Ibaraki, Japan

The SuperKEKB B-factory is now under construction. The designs of the components for the SuperKEKB have mostly been finished. This paper summarises the updated results of longitudinal impedance calculations for various components of the main rings. By summing up all available impedances, a pseudo-Green wake function with bunch length of σ_z=0.5 mm is constructed as an impedance model for consequent studies of collective effects. The results of these studies are also reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI022

Beam-Beam Studies in LHC- Beam Loss and Bunch Shortening

emittance, resonance, synchrotron, luminosity

1603

K. Ohmi
KEK, Ibaraki, Japan

In Hadron colliders, luminosity degrade various mechanism. Beam-beam related emittance growth is caused by resonances induced by crossing angle. Tune spread due to chromaticity enhances the resonances effect. A bunch shortening phenomenon related to beam-beam interaction has been observed in LHC. The bunch length has an anti-correlation with transverse emittance. This phenomenon has been studied using a weak-strong beam-beam simulation (BBWS code).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI022

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI023

Simulation of Debunching for Slow Extraction in J-PARC MR

cavity, beam-loading, resonance, impedance

1606

M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, K. Takata, M. Toda, M. Yoshii
KEK, Ibaraki, Japan
A. Schnase
GSI, Darmstadt, Germany

The J-PARC MR delivers a proton beam for nuclear physics experiments with slow extraction. The beam is debunched at flat top to obtain a coasting beam by turning off the rf voltage. The controlled emittance blow-up before the flat top has been investigated to mitigate the microwave instability. Beam loading effect can disturb the uniformity of the debunching at the flat top. We describe the results of the particle tracking simulation whole acceleration cycle including the controlled emittance blow-up and the beam loading effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI024

Simulation of Space Charge Dynamics on HPC

space-charge, GPU, distributed, controls

1609

N.V. Kulabukhova, S.N. Andrianov
St. Petersburg State University, St. Petersburg, Russia
A. Bogdanov, A. Degtyarev
Saint Petersburg State University, Saint Petersburg, Russia

To represent the space charge forces of beam a software based on analytical models for space charge distributions was developed. Special algorithm for predictor-corrector method for beam map evaluation scheme including the space charge forces were used. This method allows us to evaluate the map along the reference trajectory and to analyze beam envelope dynamics. In three dimensional models the number of computing resources we use is significant. For this purpose graphical processors are used. This software is a part of Virtual Accelerator concept which is considered as a set of services and tools of modeling beam dynamics in accelerators on distributed computing resources.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI027

Detailed Magnetic Model Simulations of the H⁻ Injection Chicane Magnets for the CERN PS Booster Upgrade, including Eddy Currents, and Influence on Beam Dynamics

injection, vacuum, emittance, space-charge

1618

E. Benedetto, B. Balhan, J. Borburgh, C. Carli, V. Forte, M. Martini
CERN, Geneva, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France

The CERN PS Booster will be upgraded with an H⁻ injection system. The chicane magnets for the injection bump ramp-down in 5 ms and generate eddy currents in the inconel vacuum chamber which perturb the homogeneity of the magnetic field. The multipolar field components are extracted from 3D OPERA simulations and are included in the lattice model. The beta-beating correction is computed all along the ramp and complete tracking simulations including space-charge are performed to evaluate the impact of these perturbations and their correction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI027

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI029

The CERN PS Booster Space Charge Simulations with a Realistic Model for Alignment and Field Errors

resonance, space-charge, lattice, alignment

1624

V. Forte, E. Benedetto, M. McAteer
CERN, Geneva, Switzerland

The CERN PS Booster is one of the machines of the LHC injector chain which will be upgraded within the LIU (LHC Injectors upgrade) project. The injection energy of the PSB will be increased to 160MeV in order to mitigate direct space charge effects, considered to be the main performance limitation, thus allowing to double the brightness for the LHC beams. In order to better predict the gain to be expected, space charge simulations are being carried out. Efforts to establish a realistic modeling of field and alignment errors aim at extending the basic model of the machine towards a more realistic one. Simulations of beam dynamics with strong direct space charge and realistic errors are presented and analysed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI031

A Precise Beam Dynamics Model of the PSI Injector 2 to Estimate the Intensity Limit

space-charge, cyclotron, extraction, acceleration

1630

A.M. Kolano, R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom
A. Adelmann, C. Baumgarten
PSI, Villigen PSI, Switzerland

We describe a precise beam dynamics model of the production set up of the Injector 2 Cyclotron at the Paul Scherrer Institut (PSI). Injector 2 is a 72 MeV separate-sector cyclotron producing a high intensity proton beam up to 2.7 mA CW, which is then injected into the 590 MeV Ring Cyclotron. The model includes space charge and is calculated for optimised matched initial conditions. It has been verified with measurements. Based on this model we estimate the limits to the intensity obtainable from Injector 2. The precise beam dynamics model is based on the OPAL (Object Oriented Parallel Accelerator Library) simulation code, a tool for charged-particle optics calculations in large accelerator structures and beam lines including 3D space charge.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI036

Fast Ion Instability at CESR-TA

feedback, vacuum, ion, electron

1638

A. Chatterjee, K.J. Blaser, M. P. Ehrlichman, D. L. Rubin, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF and DOE Contracts No. PHY-0734867, No. PHY-1002467, No. PHYS-1068662, No. DE-FC02-08ER41538, No. DE-SC0006505, and the Japan/U.S. Cooperation Program.
Fast Ion Instability can lead to deterioration of an electron beam (increasing emittance and instability of a train of bunches) in storage rings and linacs. We study this at the Cornell Electron Storage Ring Test Accelerator using a 2.1 GeV low emittance beam. As the source of ions is residual gas, our measurements are conducted at various pressures, including nominal vacuum as well as injected gas (Ar, Kr). We measure turn-by-turn vertical bunch size and position, as well as the multi-bunch power spectrum. A detailed simulation is then used to compare theory with observations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI040

New BBA Algorithm for Electron Beam Orbit Steering in Linear Accelerators

quadrupole, lattice, undulator, alignment

1650

A. Sargsyan, V. Sahakyan, G.S. Zanyan
CANDLE SRI, Yerevan, Armenia
W. Decking
DESY, Hamburg, Germany

In linear accelerators or transfer lines beam-based alignment (BBA) techniques are important tools for beam orbit steering. In this paper BBA correction algorithm based on difference orbit multiple measurements is proposed. Numerical simulation results for European XFEL SASE1 and FLASH undulator section are presented, according to which the orbit alignment can be achieved within accuracy of about 2 microns and 5 microns respectively. The influence of quadrupole gradient errors is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI042

Numerical Study of the Microbunching Instability at UVSOR-III: Influence of the Resistive and Inductive Impedances

electron, impedance, wakefield, synchrotron

1656

E. Roussel, S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
M. Adachi, M. Katoh, S.I. Kimura, T. Konomi
UVSOR, Okazaki, Japan
M. Hosaka, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma
KIT, Karlsruhe, Germany
H. Zen
Kyoto University, Kyoto, Japan

At high charge, relativistic electron bunches circulating in storage rings undergo an instability, the so-called microbunching or the CSR (Coherent Synchrotron Radiation) instability. This instability is due to the interaction of the electrons with their own radiation and leads to the formation of microstructures (at millimeter scale) in the longitudinal phase space. Thanks to a new type of detector, based on superconducting thin film YBCO, it is now possible to observe directly these microstructures and follow their temporal evolution*. These experimental observations open a new way to make severe comparisons with theory. Here we present results of the modeling of the dynamics at UVSOR-III using a one dimensional Vlasov-Fokker-Planck equation. We show that to obtain a relatively good agreement between numerical simulations and experiments, we have to take into account several types of impedance such as the shielded CSR impedance but also the resistive and inductive impedances.
* First Direct, Real Time, Recording of the CSR Pulses Emitted During the Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI042

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI044

Investigation of Microbunching-instability in BERLinPro

electron, linac, space-charge, emittance

1662

S.D. Rädel, A. Jankowiak, A. Meseck
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
BERLinPro is using the new energy recovery linac technology. As, maintaining the low emittance and energy spread is of major importance in an ERL, the deep understanding and control of effects which can degrade the emittance and energy spread such as space charge effects are of interest. The microbunching caused by the longitudinal space charge forces can lead to an increase in emittance and energy spread in the arcs of the loop. In this contribution, the impacts of the microbunching instability on the beam quality and its implication for BERLinPro are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI046

Dynamics of Ion Distributions in Beam Guiding Magnets

ion, quadrupole, space-charge, electron

1668

A. Markoviḱ, G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
W. Hillert, D. Sauerland
ELSA, Bonn, Germany
A. Meseck
HZB, Berlin, Germany

Funding: Supported by the German Federal Ministry of Education and Research (BMBF) under contract number 05K13HRC.
Ions generated by synchrotron radiation and collisions of the beam with the rest gas in the vacuum chamber could be a limiting factor for the operation of electron storage rings and Energy Recovery Linacs (ERL). In order to develop beam instability mitigation strategies, a deeper understanding of the ion-cloud behaviour is needed. Numerical simulations of the interaction between electron beams and parasitic ions verified with dedicated measurements can help to acquire that knowledge. This paper presents results of detailed simulations of the interaction in quadrupole magnets and drift sections of the Electron Stretcher Accelerator ELSA in Bonn. The focus is on the evaluation of the dynamics of different ion species and their characteristic distribution in quadrupole magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI046

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI048

A Map Approach for Electron Cloud Density in a Strong LHC Dipole

electron, dipole, space-charge, collider

1674

S. Petracca, A. Stabile
U. Sannio, Benevento, Italy
A. Stabile
INFN-Salerno, Baronissi, Salerno, Italy

The luminosity is limited by the electron cloud effects in presently running and proposed future storage rings. The evolution of the electron density during the electron cloud formation can be reproduced using a bunch-to-bunch iterative map formalism. By performing simulation codes this approach has been used to obtain a numerical prediction of the coefficients in the map, while in the presence of a magnetic field an analytic formula has been obtained for the linear coefficient. The next goal is finding a theoretical prescription of the quadratic coefficient at least in the presence of magnetic dipole. Then it will be possible to reproduce, by using the map formalism, the dynamics of electron cloud without performing the simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI049

Geometric Beam Coupling Impedance of LHC Secondary Collimators

impedance, factory, HOM, wakefield

1677

O. Frasciello, S. Tomassini, M. Zobov
INFN/LNF, Frascati (Roma), Italy
A. Grudiev, N. Mounet, B. Salvant
CERN, Geneva, Switzerland

Funding: Work supported by European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404
The High Luminosity LHC project is aimed at increasing the LHC luminosity by an order of magnitude. One of the key ingredients to achieve the luminosity goal is the beam intensity increase. In order to keep under control beam instabilities and to avoid excessive power losses a careful design of new vacuum chamber components and an improvement of the present LHC impedance model are required. Collimators are the main impedance contributors. Measurements with beam have revealed that the betatron coherent tune shifts were by about a factor of 2 higher with respect to the theoretical predictions based on the current model. Up to now the resistive wall impedance has been considered as the major impedance contribution for collimators. By carefully simulating their geometric impedance we show that for the graphite collimators with half-gaps higher than 10 mm the geometric impedance exceeds the resistive wall one. In turn, for the tungsten collimators the geometric impedance dominates for all used gap values. Hence, including the geometric collimator impedance into the LHC impedance model enabled us to reach a better agreement between the measured and simulated collimator tune shifts.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI050

Numerical Calculation and Experiment of Ion Related Phenomenon in SPring-8 Storage Ring

ion, electron, storage-ring, experiment

1680

A. Mochihashi, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

In the SPring-8 storage ring, various kinds of bunch filling pattern are available. Under some bunch filling patterns, residual gas ions created by scattering process between high energy electrons and residual gas molecules can be trapped stably around the electron beam and disturb the original motion of the beam. We have considered the stability of the electron beam due to the ion related phenomenon under several bunch filling patterns by computer simulation. In the simulation, we have modeled the electron bunch as single particle and the residual gas ions as macroparticles. The number of the trapped ions, size of the ion cloud and change in betatron oscillation amplitude of the beam under several filling pattern conditions will be discussed. We have also performed experiments for stability of the beam under equally spaced bunch filling patterns which give severe condition for the ion related instability. The numerical calculations and the experimental results will be discussed in the presentation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI051

Comparison between Measurements and Orbit Code Simulations for Beam Instabilities due to Kicker Impedance in the 3-GeV RCS of J-PARC

impedance, injection, kicker, acceleration

1683

P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, Y. Shobuda, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The transverse impedance of the extraction kicker magnets is the most dominant beam instability source in the 3-GeV Rapid Cycling Synchrotron of J-PARC. The instability occurs when chromaticity is fully corrected during acceleration but on the other hand no instabilities are observed for a full chromatic correction only at the injection energy even for a beam power up to 500 kW. However, the situation may change for a beam power of 1 MW and also for the upgraded injection beam energy from the present 181 MeV to the 400 MeV, as space charge effect in the non-relativistic region is believed to suppress the growth rate of beam instability. In order to study the kicker impedance in detail, recently we have introduced measured time dependent impedance source in the ORBIT simulation code in a realistic manner. The ORBIT code itself has also been well upgraded and given realistic features for application to synchrotrons. We have also carried out a systematic experimental study for a maximum beam power of 500 kW. In this paper, a detail comparison between measurements and corresponding simulations including 1 MW simulation results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI052

Analysis of Single Bunch Measurements at the ALBA Storage Ring

impedance, synchrotron, vacuum, undulator

1686

T.F.G. Günzel, U. Iriso, F. Pérez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
E. Koukovini-Platia, G. Rumolo
CERN, Geneva, Switzerland

Measurements of the vertical single bunch mode detuning and the TMCI threshold at zero chromaticity were carried out and their results were compared to the theoretical expectation. Around 65% of the found mode detuning can be explained by a developed transverse impedance model. A good bunch length parametrisation with current contributed essentially to this result. The analysis of single bunch measurements at non-zero chromaticity will also be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI054

FEM Analysis of Beam-coupling Impedance and RF Contacts Criticality on the LHC UA9 Piezo Goniometer

impedance, resonance, experiment, coupling

1692

A. Danisi, R. Losito, A. Masi, A. Passarelli, B. Salvant, C. Zannini
CERN, Geneva, Switzerland

The UA9 piezo-goniometer has been designed to guarantee micro-radians-accuracy angular positioning of a silicon crystal for a crystal collimation experiment in the LHC, and to minimize the impact on the LHC beam-coupling impedance. This paper presents a Finite Element Method (FEM) study of the device, in both parking and operational positions, to evaluate its impact on the LHC impedance budget. The study has been a progressive simulation work, started from the simplification of the original detailed design, and aimed at highlighting the effect of single details (e.g. objects in confining chambers) on the longitudinal and transverse components of beam-coupling impedance. In addition, the shielding contribution of the RF gaskets has been carefully evaluated, with the objective to assess the consequences for operation in case of their failure. Sensitivity analyses to simulation parameters are also performed, in order to test the FEM model robustness. A final word is drawn on the overall device impedance criticality.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI056

Beam Measurements of the LHC Impedance and Validation of the Impedance Model

impedance, emittance, damping, synchrotron

1698

J.F. Esteban Müller, T. Argyropoulos, T. Bohl, N. Mounet, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland

Different measurements of the longitudinal impedance of the LHC done with single bunches with various intensities and longitudinal emittances during measurement sessions in 2011-2012 are compared with particle simulations based on the existing LHC impedance model. The very low reactive impedance of the LHC, with Im(Z/n) around 0.1 Ohm, is not easy to measure. The most sensitive observation is the loss of Landau damping during acceleration, which shows at which energy bunches become unstable depending on their parameters. In addition, the synchrotron frequency shift due to the reactive impedance was estimated following two methods. Firstly, it was obtained from the peak-detected Schottky spectrum. Secondly, a sine modulation in the RF phase was applied to the bunches with different intensities and the modulation frequency was scanned. In both cases, the synchrotron frequency shift was of the order of the measurement precision.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI057

Review of the Transverse Impedance Budget for the CLIC Damping Rings

impedance, damping, wiggler, operation

1701

E. Koukovini-Platia, G. Rumolo
CERN, Geneva, Switzerland

Single bunch instability thresholds and the associated coherent tune shifts have been evaluated in the transverse plane for the damping rings (DR) of the Compact Linear Collider (CLIC). A multi-kick version of the HEADTAIL code was used to study the instability thresholds in the case where different impedance contributions are taken into account such as the broad-band resonator model in combination with the resistive wall contribution from the arcs and the wigglers of the DR. Simulations performed for positive values of chromaticity showed that higher order bunch modes can be potentially dangerous for the beam stability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI058

Impedance Studies of the Dummy Septum for CERN PS Multi-turn Extraction

impedance, extraction, septum, synchrotron

1704

S. Persichelli, O.E. Berrig, M. Giovannozzi, J. Herbst, J. Kuczerowski, M. Migliorati, B. Salvant
CERN, Geneva, Switzerland

A protection septum has been installed in the CERN PS section 15 in order to mitigate irradiation of the magnetic septum 16 for fast extractions towards the SPS. Impedance studies have been performed, showing that beams circulating in the septum during extraction generate sharp resonances in the coupling impedance. Impedance measurements with the wire technique have been performed, showing a good agreement with simulations. Instability rise times of trapped modes have been evaluated and compared to extraction duration. Solutions for reducing the impact on the stability of the beam have been considered.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI059

The Proton Synchrotron Transverse impedance model

impedance, kicker, space-charge, proton

4096

S. Persichelli, N. Biancacci, S.S. Gilardoni, M. Migliorati, E. Métral, B. Salvant
CERN, Geneva, Switzerland

The current knowledge of the transverse impedance of the CERN Proton Synchrotron (PS) has been established by theoretical computations, electromagnetic simulations and beam-based measurements at different energies. The transverse coherent tune and phase advance shifts as a function of intensity have been measured in order to evaluate the total effective transverse impedance and its distribution in the accelerator. In order to understand the beam dynamics, the frequency dependence of the impedance budget has also been evaluated considering the individual contribution of several machine devices. 3D models of many PS elements have been realized to perform accurate impedance simulations, while resistive wall and indirect space charge impedances have been evaluated with theoretical and numerical computations. Finally comparisons between the total budget and the measurement results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI060

Impedance Studies for the PS Finemet® Loaded Longitudinal Damper

impedance, cavity, kicker, synchrotron

1708

S. Persichelli, M. Migliorati, M.M. Paoluzzi, B. Salvant
CERN, Geneva, Switzerland

The impedance of the Finemet® loaded longitudinal damper cavity, installed in the CERN Proton Synchrotron straight section 02 during the Long Shutdown 2013-2014, has been evaluated. Time domain simulations with CST Particle Studio have been performed in order to get the longitudinal and transverse impedance of the device and make a comparison with the longitudinal impedance that was measured for a single cell prototype.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI061

Power Loss Calculation in Separated and Common Beam Chambers of the LHC

impedance, electron, coupling, cryogenics

1711

C. Zannini, G. Iadarola, G. Rumolo
CERN, Geneva, Switzerland
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy

The performance of 25 ns beams in the LHC is strongly limited by the electron cloud. To determine the amount electron cloud in the cold sections of the machine, it is very important to be able to disentangle the beam induced heating due to the beam coupling impedance from that attributable to electron cloud. This paper will focus on the calculation of the first contribution. First, the impedance model used for the calculation of the beam induced power loss is briefly discussed. Then, the methods for the calculation of the beam induced power loss in regions with one or two beams are also described. Finally, the calculated power loss is compared with the measured heat loads for both 25 and 50 ns beams in both the LHC arcs and in the inner triplets (ITs).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI061

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI062

The Mode Matching Technique Applied to the Transverse Beam Coupling Impedance Calculation of Azimuthally Symmetric Devices of Finite Length

impedance, cavity, coupling, vacuum

1714

N. Biancacci, E. Métral, B. Salvant, C. Zannini
CERN, Geneva, Switzerland
M. Migliorati, L. Palumbo
URLS, Rome, Italy
V.G. Vaccaro
Naples University Federico II and INFN, Napoli, Italy

The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be a less accurate approximation for segmented devices. In this contribution we present the extension of the study of the beam coupling impedance of a finite length device to the transverse plane. In order to take into account the finite length, we decompose the fields in the cavity and in the beam pipe into a set of orthonormal modes and apply the Mode Matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI062

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI063

Electromagnetic Simulations for Non-ultrarelativistic Beams and Application to the CERN Low Energy Machines

impedance, coupling, space-charge, vacuum

1718

C. Zannini, N. Biancacci, T.L. Rijoff, G. Rumolo
CERN, Geneva, Switzerland
T.L. Rijoff
TU Darmstadt, Darmstadt, Germany

In the framework of the PS-Booster upgrade project an accurate impedance model is needed in order to determine the effect on the beam stability and assess the impact of the new devices to be installed in the machine. CST 3-D EM simulations are widely used to estimate the impedance contribution of the different devices along the CERN accelerator complex. Unlike the highly relativistic case, in which the reliability of the EM solver has been proved in many specific cases by comparing simulations with analytical results, the nonrelativistic case has been so far not yet benchmarked. In order to use systematically CST 3-D EM simulations for the PS-Booster, or even lower energy machines like the antiproton decelerator ELENA, a validation campaign has been carried out. The main complication to single out the beam coupling impedance, as resulting from the interaction of the beam with the surroundings, consisted of removing reliably the strong contribution of the direct space charge of the source bunch, which is included in the EM calculation. The simulation results were then benchmarked with the analytical results for the case of a PEC cylindrical tube and of a ferrite loaded kicker.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI063

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI080

Emittance Optimisation in the Drive Beam Recombination Complex at CTF3

emittance, feedback, linac, controls

1754

D. Gamba, F. Tecker
CERN, Geneva, Switzerland
D. Gamba
JAI, Oxford, United Kingdom

According to the Conceptual Design Report, the power to accelerate the main colliding beams of CLIC is taken from parallel high intensity (100 A), low energy (2.37 GeV) beams. These beams are generated by long trains, accelerated by conventional klystrons and then time-compressed in the so called Drive-Beam Recombination Complex (DBRC). A scaled version of the DBRC has been built at the CLIC Test Facility (CTF3) at CERN in order to prove its principle and study any arising feasibility issues. One of the main constraints is the emittance control during the recombination process. This work presents an overview of the studies ongoing at CTF3, keeping in view possible improvements of the nominal CLIC design. In particular, a generic feedback algorithm to solve (quasi-)linear systems has been implemented and used in order to optimise the process by tuning the energy of the beam and steer the orbits in the different lines, as well matching the design dispersion. Current results and possible room for further optimisation will be shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI080

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI085

Development of a 4 GS/s Intra-bunch Instability Control System for the SPS - Next Steps

controls, feedback, kicker, pick-up

1766

J.D. Fox, J.M. Cesaratto, J.E. Dusatko, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
S. De Santis
LBNL, Berkeley, California, USA
W. Höfle, G. Kotzian, U. Wehrle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
We present the expanded system architecture in development for the control of intra-bunch instabilities in the SPS. Earlier efforts concentrated on validating the performance of a single-bunch demonstration processor. This minimal system was successfully commissioned at the SPS just prior to the LS1 shutdown. The architecture is now in expansion for more complex functionality, specifically multi-bunch control, control during energy ramps, and the expansion of the system front-end dynamic range with more sophisticated orbit offset techniques. Two designs of wideband kicker are being developed for installation and evaluation with the beam. With these GHz bandwidth devices and new RF amplifiers we anticipate being able to excite and control internal motion of the beam consistent with modes expected for Ecloud and TMCI effects. We highlight the expanded features, and present strategies for verifying the behavior of the beam-feedback system in the next series of machine measurements planned after the LS1 shutdown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI085

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI089

Numerical Technique for Nonlinear Beam-based Alignment

quadrupole, alignment, positron, damping

1778

F. Guatieri, C. Milardi
INFN/LNF, Frascati (Roma), Italy
D. Orsucci
UNIPI, Pisa, Italy

Two techniques to perform Beam-Based Alignment are presented. These techniques are intended for the difficult case arising in circular accelerators characterized by a nonlinear dependence of the Response Matrix on misalignments of the magnetic sources, where the standard approach fails. The developed algorithms have been successfully used to reconstruct misalignments in the transverse position of the quadrupoles installed in the main rings of the DAΦNE collider.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI089

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI097

Radiation Protection Concepts for the Beamline for Detector Tests at ELSA

radiation, electron, neutron, detector

1799

N. Heurich, F. Frommberger, P. Hänisch, W. Hillert
ELSA, Bonn, Germany

At the electron accelerator ELSA, a new external beamline is under construction, whose task is to provide a primary electron beam for detector tests. In the future the accelerator facility will not only be offering an electron beam to the currently implemented photoproduction experiments for hadron physics, but to the new "‘research and technology center detector physics"',whose task is to develop detectors for particle and astroparticle physics. To dump and simultaneously measure the current of the electron beam behind the detector components a Faraday cup consisting of depleted uranium is used. The residual radiation leaving the cup is absorbed in a concrete casing. The radiation protection concept for the entire area of the new beamline was designed with the help of the Monte Carlo simulation program Fluka. In addition the concrete casing, radiation protection walls were taken into account to allow a safe working environment in the room created by the shielding walls. The presentation gives an overview of the different radiation protection concepts for the new beamline for detector tests at ELSA. Furthermore, progresses at the beamline will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI097

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI101

Measurement of Neutrons Generated by 345MeV/u U-238 Beam at RIKEN RIBF

detector, neutron, target, photon

1811

N. Nakao
Shimizu Corporation, Institute of Technology, Tokyo, Japan
K. Tanaka, Y. Uwamino
RIKEN, Wako, Saitama, Japan

Neutrons generated by a 345 MeV/u uranium beam bombardment on a 3-mm-thick Be target were measured outside the target chamber using activation detectors of bismuth, aluminum and carbon at 60, 70 and 90 degrees from the beam axis. After a few days irradiation, the activation detectors were removed, and the energy spectra of photons from radionuclides generated by reactions of 209Bi(n, xn)210-xBi(x=4~10), 12C(n, 2n)11C and 27Al(n, alpha)24Na were measured using a germanium detector. Photo peak counts of corresponding photon energies were analyzed with considering detector efficiencies and a beam intensity fluctuation during the irradiation. The production rates of the radionuclides were obtained for all reactions. Monte Carlo simulation using the PHITS code was also performed. Fluxes of neutrons at the activation detectors were tallied and the energy spectra were obtained. Production rates of the radionuclides were obtained by folding the thus obtained energy spectra with activation cross section data. Comparisons with the measurements showed agreements within about 60%.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI101

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI102

Intervention Modelling at High-energy Particle Accelerators

radiation, software, target, software-tool

1814

T. Fabry, M. Baudin, B. Feral, L. Vanherpe
CERN, Geneva, Switzerland
L. Tabourot
SYMME, Annecy-le-Vieux, France

Funding: This research project has been supported by a Marie Curie Fellowship of the European Community’s Seventh Framework Programme under contract number (PITN-GA-2010-264336-PURESAFE).
An important aspect in the design and operation of high-energy particle accelerators is the planning of maintenance interventions. In the planning of these interventions, optimizing the exposure of the maintenance workers to ionizing radiation is a core issue. In this context, we have addressed the need for an interactive visual software tool. The intervention planning has been modelled mathematically. A proof-of-concept software tool has been implemented using this model, providing interactive visualization of facilities and radiation levels, tools for trajectory planning and automatic calculation of the expected integrated equivalent radiation dose. We explore the use of the software using a large experimental hall at CERN as a case study. Interactive visualization of the facilities and radiation levels, tools for interactive trajectory planning as well as automatic calculation of the expected integrated equivalent dose contracted during an intervention are explored. The obtained results prove the relevance of the developed methodology and software tool and demonstrate, among others, a better exploitation of the simulation data, leading to a potential accuracy gain.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI102

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO001

Effect of Beam Dynamics Processes in the Low Energy Ring ThomX

photon, scattering, synchrotron, synchrotron-radiation

1933

N. Delerue, C. Bruni, I. Chaikovska, I.V. Drebot, M. Jacquet, A. Variola, Z.F. Zomer
LAL, Orsay, France
A. Loulergue
SOLEIL, Gif-sur-Yvette, France

Funding: This work is supported by the French "Agence Nationale de la Recherche" as part of the program "investing in the future" under reference ANR-10-EQPX-51 and by grants from Région Ile-de-France.
As part of the R&D for the 50 MeV ThomX Compton source project, we have studied the effect of several beam dynamics processes on the evolution of the beam in the ring. The processes studied include among others Compton scattering, intrabeam scattering, coherent synchrotron radiation. We have performed extensive simulations of a full injection/extraction cycle (400000 turns). We show how each of these processes degrades the flux of photons produced and how a feedback system contributes to recovering most of the flux.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO001

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO002

Studies of Ultrashort THz Pulses at DELTA

electron, laser, detector, radiation

1936

P. Ungelenk, L.-G. Böttger, S. Hilbrich, H. Huck, M. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick
DELTA, Dortmund, Germany
S. Bielawski, C. Evain, M. Le Parquier, E. Roussel, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
N. Hiller, V. Judin, J. Raasch, P. Thoma
KIT, Karlsruhe, Germany

Funding: Work supported by the DFG, the BMBF, and the state of NRW.
At DELTA, a 1.5-GeV electron storage ring operated as a light source by the Center for Synchrotron Radiation at the TU Dortmund University, coherent ultrashort THz pulses are routinely generated by density-modulated electron bunches. Tracking simulations as well as experimental studies using ultrafast THz detectors and an FT-IR spectrometer aim at understanding the turn-by-turn evolution of the density modulation after an initial laser-electron interaction. Furthermore, intensity-modulated laser pulses are applied to create narrow-band THz radiation. This setup is part of the new short-pulse facility based on coherent harmonic generation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO012

New Injection System of Siberia-2 Light Source

injection, kicker, septum, electron

1965

S.I. Tomin, V. Korchuganov
NRC, Moscow, Russia

The storage ring Siberia-2 is SR source of second generation with circumference 124 m. The electron beam is injected into the ring at the energy 450 MeV. The Siberia-2 injection system was initially consisted of two high voltage rectangular pulses generators connected to the two in-vacuum strip – line kickers of traveling wave (wave impedance 50 Ohm) – a pre-inflector and an inflector. The amplitude voltage was 25-35 kV with 20 ns pulse duration and 2-3 ns pulse front/fall. Recently the new injection generators were proposed. Injection system now includes the same kickers and the new 1 microsecond pulse duration and 10 kV voltage amplitude generators. A dynamics of the electron beam after injection moment is considered in the article. The possibility of effective injection with kikers pulse duration over 2 periods of revolution of the electron beam is shown. The results of the new injection system commissioning are also demonstrated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO015

RF Injector Beam Dynamics Optimization for LCLS-II

emittance, linac, brightness, cathode

1974

C. F. Papadopoulos, D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA
P. Emma, T.O. Raubenheimer, J.F. Schmerge, L. Wang, F. Zhou
SLAC, Menlo Park, California, USA

Funding: This work was supported in part by the Work supported, in part, by the LCLS-II Project and by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
LCLS-II is a proposal for a high repetition rate (>1 MHz) FEL, based on a CW, superconducting linac. The LCLS-II injector is being optimized by a collaboration from Cornell University, Fermilab, LBNL, and SLAC. There are a number of different possible technical choices for the injector including an rf gun or a high voltage DC gun. In this paper we present the status of the simulations for the injector optimization for an rf gun choice for LCLS-II. A multiobjective genetic optimizer is implemented for this reason, and optimized solutions for different bunch charges, corresponding to different operating modes, are presented. These operating points are also the initial part of the start-to-end simulations for LCLS-II. Finally, we discuss the trade-offs between compression and brightness conservation in the low energy (<100 MeV) part of the accelerator, as well as the status of sensitivity studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO015

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO018

Theoretical Maximum Current of the NSLS-II Linac

linac, beam-loading, cavity, gun

1980

R.P. Fliller, F. Gao, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An analysis of the maximum available NSLS-II linac current was performed as part of the preparation for NSLS-II Booster commissioning. The analysis was necessary in order to establish the maximum beam current available from the linac and the maximum current that would be available to the booster accelerator. In this paper we discuss the assumptions that were used in determining the maximum linac current, the model of the linac and comparison to operational conditions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO019

Comparison of the NSLS-II Linac Model to Measurements

linac, cathode, emittance, gun

1983

R.P. Fliller
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The NSLS-II linac and associated transport lines were successfully installed and commissioned in the spring of 2012. Various beam measurements were performed to ensure that the linac met specifications and would be a suitable injector for the NSLS-II booster. In this paper we discuss the outcomes of these measurements and compare them to the model of the NSLS-II linac.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO023

Preventing Superconducting Wiggler Quench during Beam Loss at the Canadian Light Source

wiggler, electron, radiation, storage-ring

1992

W.A. Wurtz, L.O. Dallin, M.J. Sigrist, J.M. Vogt, M.S. de Jong
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source utilizes two superconducting wigglers for the production of hard x-rays. These superconducting wigglers often quench during beam loss, even though tracking calculations predict that the beam is lost on an aperture far from the wigglers. We present measurements that suggest the tracking simulations are correct and the electron beam indeed strikes the predicted limiting inboard aperture. By simulating the interaction of the beam with the aperture, we find that some scattered electrons can retain sufficient energy to remain inside the storage ring. The simulations show that some of these scattered electrons strike the wiggler vacuum chamber and deposit energy in the superconducting coils, causing the quench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO024

Simulation of a Long-period EPU Operating in Universal Mode at the Canadian Light Source

polarization, alignment, dynamic-aperture, photon

1995

W.A. Wurtz, D. Bertwistle, L.O. Dallin, M.J. Sigrist
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source is implementing an elliptically polarizing undulator (EPU) with period 180 mm for the production of soft x-rays with variable polarization. Two issues arise from implementing such a device. First, a long-period EPU can cause significant loss of dynamic aperture due to strong dynamic focusing. Second, to compensate for polarization effects due to beamline optics, the EPU must be able to produce light with an arbitrary polarization at the source point, which is referred to as universal mode. We present a scheme for operating the EPU in universal mode and discuss the use of BESSY-style current strips in order to compensate for dynamic effects. Tracking simulations suggest that dynamic aperture can be sufficiently recovered for all required operating points in universal mode.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO041

Undulator Radiation Spectral Broadening Due To Radiation Energy Loss

undulator, radiation, electron, photon

2035

N.V. Smolyakov
NRC, Moscow, Russia

A relativistic electron passing through an undulator generates electromagnetic radiation at the expenses of its own kinetic energy. This effect is usually not taken into account if the number of periods of the undulator is relatively small (100 - 200). However, at FEL facilities, long installations have been built, planned or are under construction, where many undulators are installed one after another for a total of several thousand undulator periods. For instance, the SASE1 and SASE2 lines at the European XFEL will consist of 35 undulators with 124 periods each. In this case, because of the electron energy decrease along its trajectory, the radiation from different undulators will drop out of synchronism. As a result, the radiation spectral line will be much wider. In the presented report, this effect was analyzed analytically and numerically. An expression for the critical number of undulator periods, when the effect of electron energy loss should be properly taken into account, is derived. It is found that, for the case of the European XFEL, this number is about 1200 periods.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO048

A Concept of a Universal Superconducting Undulator

undulator, electron, storage-ring, FEL

2050

Y. Ivanyushenkov
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Tiny round electron beams of free-electron lasers and relatively new diffraction-limited storage rings make possible utilization of electromagnetic helical undulators based on double-helical windings. It has been understood for a while that a coaxial pair of double-helical windings can generate helical as well as planar magnetic fields*. Such a coil structure can potentially be realized with superconducting windings thus forming the concept of a universal superconducting undulator (Universal SCU). An example of a possible universal SCU for the recently suggested Advanced Photon Source multi-bend achromat storage ring is given in this paper. The results of the magnetic simulation together with initial cryogenic considerations are presented.
* D.F. Alferov, Yu.A. Bashamakov, E. G. Bessonov, Sov. J. Tech. Phys. 21(11), (1976) 1408.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO055

Development of a Quasi 3-D Ellipsoidal Photo Cathode Laser System for PITZ

laser, electron, emittance, cathode

2069

T. Rublack, M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: Funded by the German Federal Ministry of Education and Research (BMBF) project 05K10CHE in the framework of the German-Russian collaboration "Development and Use of Accelerator-Based Photon Sources".
3-D ellipsoidal photo cathode laser pulses are considered as the next step in optimization of photo injectors required for a successful operation of linac based free electron lasers. Significant improvements in electron beam emittance obtained from the beam dynamics simulations using such laser pulses compared to the conventional cylindrical pulses motivated the experimental studies in order to develop a laser system for quasi 3-D ellipsoidal pulses. The Institute of Applied Physics (Nizhny Novgorod, Russia) in collaboration with the Joint Institute of Nuclear Research (Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen site (PITZ) is developing such a photo cathode laser system. Experimental tests of the laser system with photoelectron beam production are planned at PITZ. The laser pulse shaping is realized using the spatial light modulator technique. The laser system is capable of pulse train generation. First cross-correlation measurements were done demonstrating in principle the ability to generate and measure quasi ellipsoidal laser pulses. In this contribution the overall set-up, working principle and the actual progress of the development will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO055

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO066

Study for Space Charge effect in tune space at J-PARC MR

coupling, resonance, space-charge, quadrupole

2100

K. Ohmi, S. Igarashi
KEK, Ibaraki, Japan
H. Harada
JAEA, Ibaraki-ken, Japan
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Choice of tune operating point is serious for operation of high intensity proton machine. Space charge force induces tune spread and nonlinear resonance. Nonlinear resonances are also contained in accelerator lattice. We discuss optimization of operating point based on space charge simulation in J-PARC Main Ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO066

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO068

SPS Beam Steering for LHC Extraction

extraction, operation, quadrupole, closed-orbit

2106

E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
H. Bartosik, K. Cornelis, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, Y. Papaphilippou, J. Wenninger
CERN, Geneva, Switzerland

The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO068

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO074

Performance of the ESS High Energy Beam Transport under Non-nominal Conditions

target, quadrupole, dipole, optics

2124

H.D. Thomsen, S.P. Møller
ISA, Aarhus, Denmark

With a nominal beam power of 5 MW, the demands for low relative beam losses in the ESS linac are unprecedented. In the HEBT, where the beam first reaches full power, this is especially relevant. The acceptance of the HEBT should thus encompass beams of non-nominal parameters and ideally be tolerant to partial hardware failure for at least a pulse train of 2.86 ms. In this paper, the sensitivity towards errors in beam parameters and optical elements will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO074

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO077

Thermal Neutron Beam Characterization at the HRPT Instrument at the Swiss Spallation Neutron Source

neutron, shielding, target, proton

2134

V. Talanov, D. Cheptiakov, U. Filges, S.H. Forss, T. Panzner, V. Pomjakushin, E. Rantsiou, T. Reiss, M. Wohlmuther
PSI, Villigen PSI, Switzerland

The Swiss spallation neutron source (SINQ) at Paul Scherrer Institut (PSI) provides beams of thermal and cold neutrons to different neutron instruments. In a view of a potential SINQ upgrade, an experimental program characterizing the current performance of SINQ neutron beams was started in 2013. We present experimental results of the irradiation of imaging plates and gold foils at one of SINQ thermal neutron beam lines that hosts the high resolution powder diffractometer (HRPT) and compare the experimental results to the numerical MCNPX simulations of the neutron flux from the SINQ target-moderator system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO087

Magnetic-field Measurements of Superconducting Magnets for a Heavy-ion Rotating-gantry and Beam-tracking Simulations

superconducting-magnet, ion, heavy-ion, quadrupole

2159

S.S. Suzuki, T. Furukawa, Y. Hara, Y. Iwata, K. Mizushima, S. Mori, K. Noda, T. Shirai, K. Shoda
NIRS, Chiba-shi, Japan
N. Amemiya
Kyoto University, Kyoto, Japan
H. Arai, T. Fujimoto
AEC, Chiba, Japan
T.F. Fujita
National Institute of Radiological Sciences, Chiba, Japan
Y. Nagamoto, T. Orikasa, S. Takayama, T. Yazawa
Toshiba, Tokyo, Japan
T. Obana
NIFS, Gifu, Japan
T. Ogitsu
KEK, Ibaraki, Japan

Manufacture of superconducting rotating-gantry for heavy-ion radiotherapy is currently in progress. This rotating gantry can transport heavy ions having 430 MeV/nucleon to an isocenter with irradiation angles of over 0-360 degrees, and enable advanced radiation-therapy. The three-dimensional scanning-irradiation method is performed in this rotating gantry. Therefore, uniformity of magnetic field is quite important since scanned beams traverse through these superconducting magnets before reaching to the isocenter. In the present work, we precisely measured the magnetic-field distributions of the superconducting magnets for the rotating gantry. We used Hall probes to measure the magnetic field. The magnetic-field distributions were determined by measuring Hall voltage, while moving the Hall probes on a rail, which has the same curvature as a center trajectory of beams. The measured-field distributions were compared with calculated distributions with a three-dimensional electromagnetic-field solver, the OPERA-3D code. Furthermore, beam-tracking simulations were performed by using the measured magnetic-field distributions to verify the design of the superconducting magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO087

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO092

Comparisons and Simulations of Superconducting Dipole Magnets for JINR Carbon Ion Gantry

dipole, ion, synchrotron, vacuum

2174

E. Syresin, N.A. Morozov, D. Shvidkiy
JINR, Dubna, Moscow Region, Russia

A medical complex for carbon ion therapy has been developed in the JINR based on the own technology of the superconducting ion synchrotron - Nuclotron. One important feature of this project is related to the application of superconducting gantry. In the project, two schemes of superconducting gantries have been considered. In the first scheme, the last gantry element is supposed to be represented by a superconducting magnet with a scan region in it of 20 × 20 cm. In the second scheme the gantry consists of four 45°bending sections, each including two similar dipole magnets of a low aperture (about 120 mm). Such gantries are intended for multiple raster scanning with a wide carbon beam and the technique of layer wise irradiation with a spread out Bragg peak of several mm. The comparison and simulation of superconducting dipole magnet for JINR carbon ion gantry is under discussion.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO097

The Base Parameters of the Compact 27 GHz Electron Linac for Medical Application

electron, linac, injection, coupling

2189

S.M. Polozov, T.V. Bondarenko, Yu.D. Kliuchevskaia, V.I. Rashchikov
MEPhI, Moscow, Russia

A compact and light-weight electron linac is attractive for a number of medical applications including intra-operational and cyber-knife systems. The design of such an accelerator can nowadays be based on using of a powerful high-voltage high-frequency gyrotron which can provide now in pulsed regime a peak power up to 15 MW at the frequency about of 30 GHz. Taking into account this possibility, the paper presents the results of design and numerical simulations for the electron beam dynamics in a linac with the operating frequency of 27 GHz. Designed linac consists of two parts: gentle buncher and main accelerating section. The beam bunching is complicated at 1 cm wavelength because high energy about 2 MeV is necessary for beam injection into the main stage with v/c=1. Beam dynamics simulations are held using BEAMDULAC-BL code*. The electrodynamics of accelerating structure based on biperiodic structure is presented. The electron gun simulation is also discussed. The RF feeding is planned to be realized using a gyrotron to be designed in IAP RAS. The gyrotron is capable to produce 2 MW peak RF power in pulses with pulse duration 400 μs and repetition rate 10 Hz.
T.V. Bondarenko, E.S. Masunov, S.M. Polozov. BEAMDULAC-BL code for 3D simulation of electron beam dynamics taking into account beam loading and coulomb field. PAST, 2014 (in press).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO097

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO098

Producing Two-photon Planar Sources at an Electron Accelerator

target, electron, photon, radiation

2192

V.L. Uvarov, N.P. Dikiy, A.N. Dovbnya, Yu.V. Lyashko, Yu.V. Rogov, V.A. Shevchenko, A.Eh. Tenishev
NSC/KIPT, Kharkov, Ukraine

Gamma-sources with two-energy spectrum are used in industrial and medical diagnostics for quantitative introscopy (tomography). Commonly, such sources are obtained by a reactor technology (153Gd) or using an ultrastable X-ray tube with properly shaped spectrum of radiation. We suggested utilize the 179Ta isotope (Ex~ 55 keV, T1/2= 665 day) in combination with 57Co (Eγ=122 keV, T1/2=273 day). A soft technology for producing planar sealed 179Ta/57Co sources at an electron accelerator by X-ray irradiation of a target from natural tantalum and nickel was developed. The isotope yield and absorbed power of radiation in the target device vs electron beam energy were calculated using a modified transport code PENELOPE-2008. The results of experiment conducted to determine the yields of the target isotopes and by-products are in good agreement with the simulation data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO098

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO104

Backscattering X-ray System by using 950 keV X-band Linac X-ray Source

photon, target, detector, linac

2209

C. Liu
The University of Tokyo, Tokyo, Japan
T. Fujiwara, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
J. Kusano
Accuthera Inc., Kawasaki, Kanagawa, Japan

Recently several tunnel collapses have happened in the world. To prevent this kind of accidents, the non-destructive inspection for tunnel is seriously needed. Backscattering X-ray system which makes one-side operation possible is a very important way to solve this problem. But the backscattering X-ray systems using X-ray tubes could only get the superficial information of the concrete target*. Now we are using our 950 keV X-ray source to construct the backscattering X-ray system to detect the deeper part of the concrete target.
*D. Shedlok, T. Edwards, C.Toh, “X-ray Backscatter Imaging for Aerospace Applications”, Review of Progress in Quantitative Nondestructive Evaluation, Volume 30 AIP Conf. Proc. 1335, 509-516, (2011).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO104

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO109

Experimental Determination of Heavy Nuclei Fission Cross-sections under Relativistic Deuterons Irradiation on the Accelerator Complex “Nuclotron” for Purposes of Transmutation and Energy Amplification

neutron, detector, target, experiment

2221

V.V. Bukhal, A.A. Patapenka, A.A. Safronava
JIPNR-Sosny NASB, Minsk, Belarus
M. Artiushenko
NSC/KIPT, Kharkov, Ukraine
K.V. Husak
The Joint Institute of Power and Nuclear Reserach - "SOSNY" NASB, Minsk, Belarus
S.I. Tyutyunnikov
JINR, Dubna, Moscow Region, Russia

Experimental studies of neutron spectra of three different subcritical assemblies driven by an accelerator (Accelerator Driven Systems – ADS) for investigation of the possibility of transmutation and energy amplification have been carried out. The assemblies were constructed in the framework of the international project “Energy and Transmutation of Radioactive Wastes” and experiments with them are running in the Veksler and Baldin Laboratory of High Energy Physics of the Joint Institute for Nuclear Research (Dubna, Russia) at the accelerator complex “Nuclotron”. In this paper the results of measurements of 239Pu(n, f), 235U(n, f), 238U(n, f) and 238U(n,γ) reactions cross-sections and reactions rates using solid state nuclear track detectors and activation gamma-spectroscopy are presented. A comparison of the experimental results with FLUKA calculations is given. The obtained experimental values characterize the neutron spectra in the experimental points and allow the efficiency of the ADS technology for the systems with similar parameters to be evaluated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO109

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRO112

Fusion Based Neutron Sources for Security Applications: Energy Optimisation

neutron, target, proton, shielding

2230

S.C.P. Albright, R. Seviour
University of Huddersfield, Huddersfield, United Kingdom

There is a growing interest in the use of neutrons for national security. The majority of work on security focuses on the use of either sealed tube DT fusors or fission sources, e.g. Cf-252. Fusion reactions enable the energy of the neutron beam to be chosen to suit the application, rather than the application being chosen based on the available neutron beam energy. In this paper we discuss simulations of fusion reactions demonstrating the broad range of energies available and methods for adapting the neutron beam energy produced by target/projectile combinations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO112

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME028

Systematic Measurement of the Pumping Capabilities of Cryogenic Surfaces

radiation, cryogenics, vacuum, operation

2317

F. Chill, O.K. Kester
IAP, Frankfurt am Main, Germany
L.H.J. Bozyk, O.K. Kester, P.J. Spiller
GSI, Darmstadt, Germany

The quality of the beam vacuum is crucial for the stable operation of synchrotrons with high intensity heavy ions. Cryogenic surfaces are capable of pumping residual gases by cryocondensation until the saturated vapor pressure (SVP) is reached. Even at LHe temperatures the SVP of hydrogen is too high. If the surface coverage is sufficiently low, residual gas can also be bound by cryosorption, yielding in acceptable low pressures. These pumping capabilities can be described by two parameters, both dependent on surface temperature and coverage: The sticking probability (SP), that is the chance of an impinging gas particle to be bound, and the mean sojourn time (MST) of a particle on the surface. To acquire these parameters, an experimental setup is currently built at GSI. It consists of a cryogenic chamber, cooled by a cold head and a warm part with vacuum diagnostics and gas inlet. It allows monitoring the pumping speed and also the equilibrium pressure of the cryogenic part from which the SP and the MST can be deducted. The results will be used to further improve the accuracy of the dynamic vacuum simulations in cryogenic areas of particle accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME028

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME032

Detailed Investigation of the Low Energy Secondary Electron Yield of Technical Cu and its Relevance for LHC

electron, gun, dipole, operation

2329

R. Cimino, L.A. Gonzalez, A.L. Romano
INFN/LNF, Frascati (Roma), Italy
R. Cimino, G. Iadarola, G. Rumolo
CERN, Geneva, Switzerland
R. Larciprete
ISM-CNR, Rome, Italy

The detailed study of the Secondary Electron Yield (SEY) of technical Cu for very low electron landing energies (from 0 to 30 eV) is very important for electron cloud build up in high intensity accelerators and in many other fields of research. However, this question has been rarely addressed due to the intrinsic experimental complexity to control very low energy electrons. Furthermore, several results published in the past have been recently questioned for allegedly suffering from experimental systematics. In this paper, we critically review the experimental method used to study low energy SEY and define more precise energy regions, in which the experimental data can be considered valid. The new SEY curves are then fed into e-cloud simulation codes to address their impact for electron cloud predictions in the LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME036

Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio

vacuum, cathode, electron, experiment

2341

J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Nature Science Foundation of China under Grant Nos.11075157.
In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME036

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME037

Monte Carlo Simulations of Synchrotron Radiation and Vacuum Performance of the Max IV Light Source

photon, vacuum, radiation, synchrotron

2344

M. Ady, R. Kersevan
CERN, Geneva, Switzerland
M.J. Grabski
MAX-lab, Lund, Sweden

In the MAX IV light-source in Lund, Sweden, the intense synchrotron radiation (SR) distributed along the ring generates important thermal and vacuum effects. By means of a Monte Carlo simulation package, which is currently developed at CERN, both thermal and vacuum effects are quantitatively analysed, in particular near the crotch absorbers and the surrounding NEG-coated vacuum chambers. Using SynRad+, the beam trajectory of the upstream bending magnet is calculated; SR photons are generated and traced through the geometry until their absorption. This allows an analysis of the incident power density on the absorber, and to calculate the photon induced outgassing. The results are imported to Molflow+, a Monte Carlo vacuum simulator that works in the molecular flow regime, and the pressure in the vacuum system and the saturation length of the NEG coating are determined using iterations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME038

Introduction to the Latest Version of the Test-particle Monte Carlo Code Molflow+

vacuum, injection, software, cryogenics

2348

M. Ady, R. Kersevan
CERN, Geneva, Switzerland

The Test-Particle Monte Carlo code Molflow+ is getting more and more attention from the scientific community needing detailed 3D calculations of vacuum in the molecular flow regime mainly, but not limited to, the particle accelerator field. Substantial changes, bug fixes, geometry-editing and modelling features, and computational speed improvements have been made to the code in the last couple of years. This paper will outline many of these new features, and show examples of applications to the design and analysis of vacuum systems at CERN and elsewhere.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME039

Leak Propagation Dynamics for the HIE-ISOLDE Superconducting Linac

vacuum, cryomodule, linac, cathode

2351

G. Vandoni, M. Ady, M.A. Hermann, R. Kersevan, D.T. Ziemianski
CERN, Geneva, Switzerland

In order to cope with space limitations of existing infrastructure, the cryomodules of the HIE-Isolde superconducting linac feature a common insulation and beam vacuum, imposing the severe cleanliness standard of RF cavities to the whole cryostat. Protection of the linac vacuum against air-inrush from the three experimental stations through the HEBT lines relies on fast valves, triggered by fast cold cathode gauges. To evaluate the leak propagation velocity as a function of leak size and geometry of the lines, a computational and experimental investigation is being carried out at CERN. A 28 m long tube is equipped with strain gauges installed on thin-walled flanges, as well as fast reacting glow discharge and cold-cathode gauges. A leak is opened by the effect of a cutting pendulum, equipped with an accelerometer for data acquisition triggering, on a thin aluminium window followed by a calibrated orifice. The air inrush dynamics is simulated by Test-Particle Monte Carlo in the molecular regime and by Finite Elements fluid dynamics in the viscous regime.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME044

LHC Experimental Beam Pipe Upgrade during LS1

vacuum, detector, experiment, injection

2366

G. Lanza, V. Baglin, G. Bregliozzi, P. Chiggiato
CERN, Geneva, Switzerland

The LHC experimental beam pipes are being improved during the ongoing long shutdown 1 (LS1). Several vacuum chambers have been tested and validated before their installation inside the detectors. The validation tests include: leak tightness, ultimate vacuum pressure, material outgassing rate, and residual gas composition. NEG coatings are assessed by hydrogen sticking probability measurement with the help of Monte Carlo simulations. In this paper the motivation for the beam pipe upgrade, the validation tests of the components and the results are presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME044

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME049

Coupled Simulations of the Synchrotron Radiation and Induced Desorption Pressure Profiles for the HiLumi-LHC Triplet Area and Interaction Points

vacuum, photon, electron, detector

2381

R. Kersevan, V. Baglin, G. Bregliozzi
CERN, Geneva, Switzerland

The HiLumi-LHC machine upgrade has officially started as an approved LHC project (see dedicated presentations at this conference on the subject). One important feature of the upgrade is the installation of very high-gradient triplet magnets for focusing the beams at the collision points of the two high-luminosity detectors ATLAS and CMS. Other important topics are new superconducting D1 magnets, installation of crab cavities, and re-shuffling of the dispersion suppression area. Based on the current magnetic lattice set-up and beam orbits, a detailed study of the emission of synchrotron radiation (SR) and related photon-induced desorption (PID) has been carried out. A significant amount of SR photons are generated by the two off-axis beams in the common vacuum chamber of the triplet area, about 57 m in length. Ray-tracing Montecarlo codes SYNRAD⁺ and Molflow+ have been employed in this study. The related PID pressure profiles will be shown, together with simulations using the code VASCO for the analysis of beam losses and background in the detectors, including electron cloud effects.
(*) The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME050

High Frequency Electromagnetic Characterization of NEG properties for the CLIC Damping Rings

damping, network, experiment, impedance

2384

E. Koukovini-Platia, G. Rumolo, C. Zannini
CERN, Geneva, Switzerland

Coating materials will be used in the CLIC damping rings (DR) to suppress two-stream effects. In particular, NEG coating is necessary to suppress fast beam ion instabilities in the electron damping ring (EDR). The electromagnetic (EM) characterization of the material properties up to high frequencies is required for the impedance modeling of the CLIC DR components. The EM properties for frequencies of few GHz are determined with the waveguide method, based on a combination of experimental measurements of the complex transmission coefficient S21 and CST 3D EM simulations. The results obtained from a NEG coated copper (Cu) waveguide are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME050

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME068

Mitigating Noise Sources in MTCA.4 Electronics for High Precision Measurements

coupling, instrumentation, distributed, FPGA

2436

U. Mavrič, M. Hoffmann, F. Ludwig, H. Schlarb
DESY, Hamburg, Germany

The RF field detection instrumentation plays a crucial role in modern accelerator performance. The most critical section is the transition from the analog signal processing to the digitalization. In this paper we present state of the art performance of COTS components and limitations imposed by crate-oriented solutions. We give recipes on how to optimize performance and present some of the recent results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME068

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPME077

Advanced Automatic Frequency Control System for a Dual Energy S-band RF Electron Linear Accelerator

cavity, resonance, controls, electron

2459

S.S. Cha
UST, Daejeon City, Republic of Korea
Y. Kim
ISU, Pocatello, Idaho, USA
B.C. Lee, B.N. Lee, H.D. Park, K.B. Song
KAERI, Daejon, Republic of Korea

Funding: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the ministry of science ICT & future Planning (No. 2010-0026088), and MOTIE Korea (13-DU-EE-12).
The Radiation Instrumentation Research Division of Korea Atomic Energy Research Institute is developing a 2856 MHz dual energy [9, 6 MeV] s-band RF electron linear accelerator for security inspection. The s-band dual energy electron accelerator generates dual x-ray energy by irradiating a bunched electron beam from the cavity to a tungsten target. By detecting an x-ray, the cargo security inspection system can distinguish between organic and inorganic materials. Synchronization of the resonant frequency between the cavity and RF driver is an important factor for the stable operation of an accelerator. With a low RF driver power using the AFC, stable accelerator operations and a uniform output beam power can be obtained. This indicates that an accurate cargo inspection is possible. We used phase a frequency detector that can detect a wide frequency band and synchronize the resonance frequency between the RF driver and cavity. In this paper, we introduce a more advanced AFC system than a conventional AFC system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI012

Euclid Modified SRF Conical Half-wave Resonator Design

cavity, vacuum, controls, operation

2502

E.N. Zaplatin
FZJ, Jülich, Germany
T.L. Grimm, A. Rogacki
Niowave, Inc., Lansing, Michigan, USA
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302.
The new low-beta conical Half-Wave Resonator (cHWR) is suggested for CW proton accelerators of new generation with relatively low beam loading, where frequency detune caused by microphonics and helium pressure fluctuations is essential. This particular design, considered in the paper, has operation frequency of 162.5 MHz, b=v/c=0.11, and is suitable for the first section of the PIP-II superconducting accelerator which is under development at Fermilab. The main idea of the cHWR design is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a series of cavity and helium vessel modifications to simplify their manufacturing. The whole set of numerical simulations has been generated to verify that the main parameters of the initial structure design were not affected by the proposed modifications. Here we present the main results of the cavity and helium vessel modified design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI020

Mechanical Analysis of the XFEL 3.9 GHz Cavities in support of PED Qualification

cavity, superconducting-cavity, controls, linac

2515

M. Moretti, P. Pierini
INFN/LASA, Segrate (MI), Italy
A. Schmidt
DESY, Hamburg, Germany

We present the FEA stress analysis under different mechanical conditions of the XFEL 3.9 GHz superconducting cavities. The analysis is being performed in support of the necessary qualification according to the Pressure Equipment Directive European Norms, for the operating conditions set in the European XFEL project.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI029

Simulations and Measurements of Beam Pipe Modes excited in 9-cell Superconducting Cavities

cavity, HOM, dipole, experiment

2540

A. Kuramoto
Sokendai, Ibaraki, Japan
N. Baboi
DESY, Hamburg, Germany
H. Hayano
KEK, Ibaraki, Japan

Higher order modes (HOM) excited in 9-cell superconducting cavities have been studied to detect cavity alignment. Dipole modes have been monitored, since their magnitude is proportional to beam offsets from their electrical centers. Detection of cavity alignment is important for the ILC to confirm alignment accuracy and furthermore possible source of emittance growth. We are particularly interested in beam pipe modes because they are localized in both ends of the cavity. We measured beam-induced HOM in the STF accelerator at KEK in 2012 – 2013. From the results of the measurement, we found some modes whose behaviors are like dipole mode at around 2.1 GHz instead of 2.28 GHz as calculated by R. Wanzenberg for an ideal cavity [TESLA 2001-33, September 2001]. We also measured beam induced HOM in the TESLA superconducting cavities in FLASH at DESY. In order to identify beam pipe modes and to compare the measurement with the calculation, we calculate beam pipe modes of 9-cell superconducting cavity by CST MICROWAVE STUDIO 2012 and HFSS 12. We will discuss about these calculations and the measurement.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI030

Multipactor Simulation on Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources

multipactoring, cavity, electron, acceleration

2543

Y. Iwashita, H. Fujisawa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
R. Hajima, R. Nagai, M. Sawamura
JAEA, Ibaraki-ken, Japan
T. Kubo
KEK, Ibaraki, Japan

Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program.
Superconducting spoke cavity for laser Compton scattered (LCS) photon sources is under development. The operating frequency is 325-MHz to accelerate electron beam for the LCS sources, where the size of the spoke cavity is less than a elliptical cavities with the same frequency. Because of the complicated shape of the cavity, it may be suffered from a strong multipactor effect. The recent results on the multipactor analysis will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI035

Stiffening Structure of the HWR at RISP

cavity, target, controls, operation

2552

G.-T. Park, H.J. Cha, H. Kim, H.J. Kim, W.K. Kim
IBS, Daejeon, Republic of Korea

The HWR being developed in RISP, Korea is in its final stage of the design. We consider the effects of the stiffeners in the presence of the helium vessel on the various detunings such as cool down, helium pressure fluctuation, Lorentz pressure. The interaction of the stiffened cavity with the helium jacket is studied via the coupled simulation by ANSYS and the optimal specification of the stiffeners are determined. In addition, the expected frequency shift is predicted to establish the target frequency bfor the manufacturing. The effect of the vibrational motion is also studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI040

On the Optimal Design of Elliptical Superconducting Cavities

cavity, coupling, diagnostics, target

2565

G. Costanza
Lund University, Lund, Sweden

In this paper a linear regression analysis is used to analyze the behavior of the inner cell of an elliptical cavity. The aim is to understand how the RF parameters are correlated to each other and how they are affected by the change of the geometric parameters. This is done by fitting the RF data to a linear model. The data is obtained by simulating a set of different inner cells automatically by the use of a script. The results are useful in several ways: first of all the analysis sheds light on the behavior of elliptical cavities, in particular on its limitations. The analysis is carried out in the framework of optimal design so it is useful for the cavity designer since it allows to choose the geometry at an early stage of the design. It is also possible to make predictions on the performance of the cavity which are in very good agreement with the simulations. Such predictions facilitate the design of the accelerator when choosing the type and number of cavities and when writing the specifications for the cavities to be used in the accelerator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI041

Progress of HOM Couplers for CERN SPL Cavities

HOM, cavity, niobium, factory

2568

K. Papke, F. Gerigk
CERN, Geneva, Switzerland
U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by the Wolfgang-Gentner-Programme of the Bundesministerium für Bildung und Forschung (BMBF)
In this paper we present the progress of the Higher-Order-Mode (HOM) coupler design for the high beta CERN SPL (Superconducting Proton Linac) cavities. This includes the RF transmission behavior as well as mechanical and thermal requirements and their optimizations. Warm RF measurements are presented for the first four high beta SPL Cavities made of bulk niobium. Moreover the first prototype of a HOMcoupler will be introduced and we discuss its characteristics and its tuning possibilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI041

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI049

Optimization of Window Position on Diamond SCRF Cavities

cavity, operation, coupling, impedance

2592

S.A. Pande, C. Christou
DLS, Oxfordshire, United Kingdom

The Diamond storage ring uses CESR type superconducting cavities. These cavities have a fixed coupling resulting in fixed Qext which is considerably higher than the optimum. We use 3 stub tuners to match the cavities under these non-optimum conditions. Diamond Cavity-1 will soon be refurbished. This opportunity could be used to lower the Qext on the cavity. One of the options is to modify the coupling tongue geometry along with a matching section. This may require cutting off the beam tube with the coupler for rework or it may need to be newly fabricated. We investigated another option to lower the Qext of the cavity by optimising the location of the window with respect to the cavity, maintaining the same coupling tongue geometry. The height of the waveguide on the vacuum side of the window differs from that of the coupling waveguide on the cavity resulting in a step. The location of window with respect to the cavity makes a significant difference to the ultimate Qext obtained after putting the window in place. In this paper we present the results of our numerical simulations comparing the present and the proposed window position under different operating conditions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI049

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI053

Phase Method of Measuring Cavity Quality Factor

cavity, coupling, resonance, data-analysis

2604

O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Novel method for measuring intrinsic quality factor of superconducting RF (SRF) cavities using both amplitude and phase information of forward, reflected, and transmitted cavity signal is discussed. Advantages of the method in comparison with traditional types of cavity quality factor measurements are highlighted. Computer simulations and evaluation of uncertainties for the measurements are described. Analysis of data collected at vertical test facility for SRF cavities at Fermilab is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI067

Multi-Physics Analysis of CW Superconducting Cavity for the LCLS-II using ACE3P

cavity, feedback, operation, vacuum

2645

Z. Li, C. Adolphsen, O. Kononenko, T.O. Raubenheimer, C.H. Rivetta, M.C. Ross, L. Xiao
SLAC, Menlo Park, California, USA

Funding: Work was supported by the U.S. DOE contract DE-AC02-76SF00515 and used the resources of NERSC at LBNL under US DOE Contract No. DE-AC03-76SF00098.
The LCLS-II linac utilizes superconducting technology operating at continuous wave to accelerate the 1-MHz electron beams to 4 GeV to produce tunable FELs. The TESLA 9-cell superconducting cavity is adopted as the baseline design for the linac. The design gradient is approximately 16 MV/m. The highest operating current is 300 μA. Assuming that the RF power is matched at the highest current, the optimal loaded QL of the cavity is found to be around 4·10⁷. Because of the high QL, the cavity bandwidth approaches the background microphonic detuning, and the performance of the cavity is tightly coupled to the mechanical perturbations of the cavity/cryomodule system. The resulting large phase and amplitude variations in the cavity require active feedback to achieve the 0.01% amplitude and phase stability requirements. To understand the cavity RF response and feedback requirements to the microphonics and Lorentz Force detuning, we have developed a simulation model of the RF-mechanical coupled system using parameters obtained with the multi-physics solver ACE3P. We will present the simulation results of the LCLS-II linac under different power feed scenarios and feedback schemes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI067

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI072

High Power Co-axial Couplers for SRF Cavities

Windows, klystron, SRF, network

2657

J. Guo, J. Henry, R.A. Rimmer, H. Wang, R.S. Williams
JLab, Newport News, Virginia, USA
A. Dudas, M.L. Neubauer
Muons, Inc, Illinois, USA

Funding: Work supported by Dept. of Energy grant no. DE-SC0002769
High Power RF couplers are required in a wide range of accelerator projects using superconducting RF cavities. We have proposed a novel robust coax SRF coupler design using two pre-stressed disc windows without the need of additional matching elements. The matching frequency and the power handling capacity can be easily scaled by changing the diameter and the spacing of the windows. In this paper, we will present our latest progress in the fabrication and the testing of the windows.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI072

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI077

Cryogenic Test of a 750 MHz Superconducting RF Dipole Crabbing Cavity*

cavity, radiation, cryogenics, electron

2672

A. Castilla, J.R. Delayen
ODU, Norfolk, Virginia, USA
A. Castilla, J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA
A. Castilla
DCI-UG, León, Mexico

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. With resources of NERSC, under U.S. DOE contract No. DE-AC02-05CH11231.
A superconducting rf dipole cavity has been designed to address the challenges of a high repetition rate (750 MHz), high current for both electron/ion species (0.5/3 A per bunch), and large crossing angle (50 mrad) at the interaction points (IPs) crabbing system for the Medium Energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The cavity prototype built at Niowave, Inc. has been tested at the Jefferson Lab facilities. In this work we present a detailed analysis of the prototype cavity performance at 4 K and 2 K, corroborating the absence of hard multipacting barriers that could limit the desired transverse fields, along with the surface resistance (R_s) temperature dependency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI084

Magnetic Field Optimization of SIS100 Quadrupole Units

quadrupole, multipole, dipole, sextupole

2684

K. Sugita, E.S. Fischer, A. Mierau, P. Schnizer
GSI, Darmstadt, Germany
P.G. Akishin
JINR, Dubna, Moscow Region, Russia

Superconducting heavy ion synchrotron SIS100 is the central accelerator of the FAIR accelerator complex. There are more than 10 types of the quadrupole units in SIS100 due to the combination of the quadrupoles from 3 families and several types of the corrector magnets. Magnetic field optimization of the quadrupole magnet ends including evaluation of cross talk between closely attached quadrupole and corrector magnets will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI084

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI092

Test and Simulation Results for Quenches Induced by Fast Losses on a LHC Quadrupole

injection, quadrupole, operation, proton

2706

C. Bracco, B. Auchmann, W. Bartmann, M. Bednarek, A. Lechner, M. Sapinski, R. Schmidt, N.V. Shetty, M. Solfaroli Camillocci, A.P. Verweij
CERN, Geneva, Switzerland

A test program for beam induced quenches was started in the LHC in 2011 in order to reduce as much as possible BLM-triggered beam dumps, without jeopardizing the safety of the superconducting magnets. A first measurement was performed to assess the quench level of a quadrupole located in the LHC injection region in case of fast (ns) losses. It consisted in dumping single bunches onto an injection protection collimator located right upstream of the quadrupole, varying the bunch intensity up to 3·10¹⁰ protons and ramping the quadrupole current up to 2200 A. No quench was recorded at that time. The test was repeated in 2013 with increased bunch intensity (6·10¹⁰ protons); a quench occurred when powering the magnet at 2500 A. The comparison between measurements during beam induced and quench heaters induced quenches is shown. Results of FLUKA simulations on energy deposition, calculations on quench behaviour using QP3 and the respective estimates of quench levels are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI095

Modelling of a Short-period Superconducting Undulator

undulator, alignment, software, radiation

2716

B.J.A. Shepherd, J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
V. Bayliss, T.W. Bradshaw
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
E.C. Longhi
DLS, Oxfordshire, United Kingdom

STFC, in collaboration with Diamond Light Source, are designing and building a 15.5 mm period, 1.26 T superconducting undulator. This paper describes the modelling of the undulator, using Radia and Opera. Extensive numerical modelling has been carried out to simulate the effect of manufacturing tolerances on the quality of the magnetic field, in order to meet the demanding 3° rms phase error specification.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI095

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI098

QUENCH PROTECTION STUDIES OF 11T Nb3Sn DIPOLE MODELS FOR LHC UPGRADES

dipole, extraction, injection, collimation

2725

A.V. Zlobin, G. Chlachidze, A. Nobrega, I. Novitski
Fermilab, Batavia, Illinois, USA
M. Karppinen
CERN, Geneva, Switzerland

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
CERN and FNAL are developing 11 T Nb3Sn dipole magnets for the LHC collimation system upgrade. Due to the large stored energy, protection of these magnets during a quench is a challenging problem. This paper reports the results of experimental studies of key quench protection parameters including longitudinal and radial quench propagation in the coil, coil heating due to a quench, and energy extraction and quench-back effect. The studies were performed using a 1 m long 11 T Nb3Sn dipole coil tested in a magnetic mirror configuration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI098

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI100

Magnetic Design Constraints of Helical Solenoids

dipole, solenoid, beam-cooling, emittance

2731

M.L. Lopes, S. Krave, J.C. Tompkins, K. Yonehara
Fermilab, Batavia, Illinois, USA
G. Flanagan, S.A. Kahn
Muons, Inc, Illinois, USA
K.E. Melconian
Texas A&M University, College Station, Texas, USA

Helical solenoids have been proposed as an option for a Helical Cooling Channel for muons in a proposed Muon Collider. Helical solenoids can provide the required three main field components: solenoidal, helical dipole, and a helical gradient. In general terms, the last two are a function of many geometric parameters: coil aperture, coil radial and longitudinal dimensions, helix period and orbit radius. In this paper, we present design studies of a Helical Solenoid, addressing the geometric tunability limits and auxiliary correction system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI100

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI103

Magnet Design for a Six-dimensional Rectilinear Cooling Channel - Feasibility Study

solenoid, dipole, emittance, collider

2740

H. Witte, J.S. Berg, R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA
F. Borgnolutti
LBNL, Berkeley, California, USA

Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An essential part of a potential future muon collider is ionization cooling, which is required to reduce the emittance of the muon beam. A new scheme has recently been proposed which in simulations shows an improved performance in terms of cooling efficiency and transmitted muons. The lattice of this cooling channel consists of 12 stages, each of which requires different superconducting solenoids. The most challenging stage is the last one, where the solenoids are expected to deliver 15.1T in a bore of ~4.5 cm. This paper discusses the feasibility of the solenoids for the last stage of this lattice.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI103

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRI105

Preliminary Design of Cooling System for a PrFeB-based Cryogenic Permanent Magnet Undulator Prototype at IHEP

vacuum, cryogenics, undulator, permanent-magnet

2743

Y.C. Zhang, S.P. Li, H.H. Lu, S.C. Sun, Y.F. Yang
IHEP, Beijing, People's Republic of China

A circulation cooling system is under progress for a 2-m-long PrFeB-based cryogenic permanent magnet undulator (CPMU) prototype at IHEP. Sub-cooled liquid nitrogen flows through each in-vacuum girder back and forth once. Refrigerant channels for both girders are parallel connected in vacuum chamber. Numerical simulation shows that the cooling system is able to cool down magnet array from 300 K to 83 K. Meanwhile, phase error increases about 0.1 degree.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI105

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THXA01

BPMs From Design to Real Measurement

electronics, cavity, operation, vacuum

2774

D. Lipka, S. Vilcins
DESY, Hamburg, Germany

Beam Position Monitors (BPM) are an essential tool for the operation of an accelerator. Therefore BPM systems have to be already included from the beginning in the design of a new machine. This contribution describes the development of a new BPM system up to the operation with a focus on the mechanical design. It includes the collection of the requirements and boundary conditions which defines the kind of BPM system. Following the mechanical designing process is described where simulations are used to predict the signals. These results are input parameters for the design and optimization of the electronics. Several contributions are considered which can modify the BPM signal like feedhroughs, heating due to wake losses, holders, cables and so on. The steps from the design, the prototypes and series production including laboratory and test accelerator measurements up to the commissioning are described as well.

Slides THXA01 [4.844 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THXA01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPPA00

EPS-AG Prize d) Presentation

cryogenics, electron, operation, synchrotron

2837

J.F. Esteban Müller
EPFL, Lausanne, Switzerland
J.F. Esteban Müller
CERN, Geneva, Switzerland

EPS-AG Prize d) Presentation. The Prize d) winner will present the work for which the prize is awarded, on the basis of the judging by the EPS-AG Prizes Selectin Committee.

Slides THPPA00 [3.432 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPPA00

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO004

Study of the CLIO FEL in the Far-infrared in a Partially Guided Mode

vacuum, FEL, cavity, undulator

2859

J.-M. Ortega, J.P. Berthet, F. Glotin, R. Prazeres
LCP/CLIO, Orsay, Cedex, France

The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use this chamber as a waveguide by adaptating the radius of curvature of the cavity mirrors to this regime. Then, as has been shown before* a minimum appears in the spectrum that can be produced by the FEL. We discuss the physical mechanism of this particular regime and compare it to experiments using vacuum chambers of different tranverse sizes. A good agreement is found with results of simulations and with a simple analytical formula.
* Analysis of the periodic power gaps observed in the tuning range of FELs with a partial waveguide, R. Prazeres, F. Glotin, J.-M. Ortega, Phys. Rev. STAB12, 010701 (2009)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO007

Beam-based Alignment in the European XFEL SASE1

undulator, radiation, quadrupole, FEL

2867

H. Jin, W. Decking, T. Limberg
DESY, Hamburg, Germany

The European X-ray Free Electron Laser (E-XFEL) provides an ultra-short and high-brilliant photon pulses of spatially coherent X-rays with wavelengths down to 0.05 nm by using three undulator systems. Within these undulator systems, the orbit trajectory is required to be straight to a few micron over each gain length, so that the photon beam is capable of overlapping efficiently with the electron beam. However, this requirement is not obtainable with ordinary mechanical alignment methods. For this reason, a beam-based alignment (BBA) method using BPM readings of different beam energies is applied to the E-XFEL SASE1 undulators. In this report, we describe the BBA simulation for SASE1 including alignment errors of quadrupoles and BPMs. After correction, the desired range of the orbit trajectory is attained with high confidence. In addition, to identify the reliability of an aligned orbit trajectory acquired from the BBA simulation, we present here the SASE FEL radiation simulation, in which we observe a slight decrease of radiation energy and power.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO010

Analysis of Operation of Harmonic Lasing Self-seeded FEL

undulator, FEL, radiation, electron

2876

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Harmonic lasing self-seeded FEL holds great potential for significant improvement of the the longitudinal coherence of the radiation. A gap-tunable undulator is divided into two parts by setting two different undulator parameters such that the first part is tuned to a sub-harmonic of the second part. Harmonic lasing occurs in the exponential gain regime in the first part of the undulator, also the fundamental stays well below saturation. In the second part of the undulator the fundamental mode is resonant to the wavelength, previously amplified as the harmonic. The amplification process proceeds in the fundamental mode up to saturation. In this case the bandwidth is defined by the harmonic lasing (i.e. it is reduced by a significant factor depending on harmonic number) but the saturation power is still as high as in the reference case of lasing at the fundamental in the whole undulator, i.e. the spectral brightness increases. Application of the undulator tapering in the deep nonlinear regime would allow to generate higher peak powers approaching TW level. The scheme is illustrated with the parameters of the European XFEL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO020

Linac Lattice Optimization for PAL-XFEL Hard X-ray FEL Line

linac, lattice, FEL, emittance

2900

H. Yang, J.H. Han, H.-S. Kang, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is supported by MSIP, Korea.
PAL-XFEL is designed to generate 1 – 0.06-nm FEL in hard x-ray FEL line. The linac for hard x-ray generates 10-GeV, 200-pC, and 3-kA electron beam. It consists of accelerating columns, three bunch compressors, an X-band linearizer, and dog-leg line. We conduct ELEGANT simulations to obtain the optimized lattice for hard x-ray line. The candidates of the optimized lattice are obtained by Multi-Objective Genetic Algorithm (MOGA) whose objectives are the FEL saturation power and length. These are evaluated with their error tolerances. Error tolerances are obtained by two methods of error simulations. First, the linear interpolation method is conducted in order to determine the machine tolerance. Also, we find out the dominant machine parameters to increase the beam jitter by this method. Second, the error simulations with random errors of machine parameters are conducted to verify the results of the linear interpolation method and calculate beam jittering levels. In this paper, we present the details of the optimized linac lattice for hard x-ray FEL. Also, we present the procedure of the linac lattice optimization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO023

Methods for the Optimization of a Tapered Free-Electron Laser

wiggler, radiation, FEL, electron

2909

A.W.L. Mak, F. Curbis, S. Werin
MAX-lab, Lund, Sweden

In a free-electron laser (FEL), the technique of wiggler tapering enables the sustained growth of radiation power beyond the initial saturation. With the goal to develop an X-ray FEL in the terawatt power regime, it is important to utilize this technique and optimize the taper profile, giving the wiggler parameter as a function of the distance along the wiggler line. This work examines two methods of optimization, which are based on the theoretical analysis by Kroll, Morton and Rosenbluth (KMR). Using the numerical simulation code GENESIS, the methods are applied to a case for the possible future FEL at the MAX IV Laboratory in Lund, Sweden, as well as a case for the LCLS-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO023

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO025

Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure

linac, FEL, klystron, gun

2914

A.A. Aksoy, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
D. Angal-Kalinin, J.A. Clarke
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.J. Boland
SLSA, Clayton, Australia
G. D'Auria, S. Di Mitri, C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Doğan
Dogus University, Istanbul, Turkey
T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Fang, Q. Gu
SINAP, Shanghai, People's Republic of China
A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO025

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO030

Developments in CLARA Accelerator Design and Simulations

FEL, wakefield, electron, undulator

2930

S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, A.D. Brynes, D.J. Dunning, J.K. Jones, K.B. Marinov, J.W. McKenzie, B.L. Militsyn, N. Thompson, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
I.P.S. Martin
DLS, Oxfordshire, United Kingdom

We present recent developments in the accelerator design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory. Updates on the electron beam simulations and code comparisons including wakefields are described. Simulations of the effects of geometric wakefields in the small-aperture FEL undulator are shown, as well as further simulations on potential FEL experiments using chirped beams. We also present the results of simulations on post-FEL diagnostics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO032

Studies on LPWA-based Light Sources driven by a Transverse Gradient Undulator

undulator, FEL, laser, electron

2937

T. Chanwattana, R. Bartolini, A. Seryi
JAI, Oxford, United Kingdom
R. Bartolini
DLS, Oxfordshire, United Kingdom

The Accelerator Science Laboratory (ASL) is under development at the John Adams Institute in Oxford with the aim of fostering advanced accelerator concepts and applications. The option to install a LPWA based light source driven by a transverse gradient undulator is being investigated. This report presents the accelerator physics, FEL studies and the performance expected from such a facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO033

Electron-bunch Shaping for Coherent Compton Scattering

electron, laser, radiation, scattering

4107

J.E. Thorne, P. Piot, I. Viti
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Producing high-quality x rays could have important applications to high-precision medical imaging and national security. Inverse Compton scattering involving the head-on collision of a relativistic electron bunch with a high-power laser offers a viable path toward the realization of a compact x-ray source. A method consisting in reflecting a short-pulse laser onto a “relativistic mirror” (a moving thin sheet of electrons) has been proposed and recently demonstrated as a way to enhance the back-scattered photon flux by operating in the coherent regime. In this contribution we present particle-in-cell numerical simulations of the inverse Compton scattering process and especially investigate the impact of the laser-pulse and electron-beam distributions that could substantially improve the x-ray production via coherent emission.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO039

Model-independent Description of Shot-noise, Amplification and Saturation

FEL, bunching, electron, undulator

2949

Y.C. Jing, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High-gain FEL is one of many electron-beam instabilities, which have a number of common features linking the shot noise, the amplification and the saturation. In this paper we present a new, model-independent description of the interplay between these effects and derivation of a simple formula determining the saturation and maximum attainable gain in such instabilities. Application of this model-independent formula to FEL is compared with FEL theory and simulations. We describe limitations resulting from these finding for FEL amplifiers used for seeded FELs and for Coherent electron Cooling.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO039

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO045

Design and Construction of a Thermionic Cathode RF Electron Gun for Iranian Light Source Facility

gun, electron, linac, emittance

2965

A. Sadeghipanah, H. Ghasem, J. Rahighi, Kh.S. Sarhadi
ILSF, Tehran, Iran

We present a program for the design and construction of a thermionic cathode RF gun to produce bright electron beams, consisting in the first step toward the possible development of S band linac based pre-injector at Iranian Light Source Facility (ILSF). The program is aimed at the goal to attain a beam quality as requested by ILSF. As a first step within this mainstream, we are currently developing a thermionic cathode side coupling RF electron gun which is expected to deliver 100 pC bunches with emittances below 2 mm-mrad at 2.5 MeV. We report the performed simulation and design activity, as well as cold test results of first fabricated prototype, which are in good agreement with simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO053

Ion Effects in the Cornell ERL High Intensity Photoinjector

ion, resonance, radiation, electron

2989

S.J. Full, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We present our first measurements of trapped ions in the Cornell energy recovery linac (ERL) photoinjector. During high intensity operation, ions become trapped inside of the electric potential generated by the electron beam and oscillate transversely with a characteristic frequency. At high beam currents, electron beam-ion interactions result in excessive radiation, primarily due to beam losses and bremsstrahlung. However, by shaking the beam at the trapped ion's oscillation frequency, we are able to drive a resonance that severely reduces or eliminates this radiation. This both confirms the viability of beam shaking as an ion mitigation strategy inside high intensity injectors, and allows us to measure the trapped ion oscillation frequencies indirectly. Experimental data for a beam energy of 5 MeV, a bunch repetition rate of 1.3 GHz, and beam currents up to 20 mA, as well as simulations to describe our data and the beam shaking principle are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO056

Estimation of Systematic Errors for Deuteron Electric Dipole Moment (EDM) Search at a Storage Ring

polarization, dipole, experiment, extraction

2998

S. Chekmenev
RWTH, Aachen, Germany

An experimental method which is aimed to find a permanent EDM of a charged particle was proposed by JEDI (Jülich Electric Dipole moment Investigations) collaboration in 2012*. EDMs can be observed by their small influence on spin motion. The only possible way to perform a direct measurement is to use a storage ring. For this purpose it was decided to carry out the first precursor experiment at the Cooler Synchrotron (COSY). Since the EDM of a particle violates CP invariance and is expected to be tiny, treatment of all various sources of systematic errors should be done with a great level of precision. One should clearly understand how misalignments of the magnets affects the beam and the spin motion. In reality, one of the methods to investigate spin behavior in the presence of misalignments in a storage ring is to mimic their influence on the beam parameters using small orbit kicks with different amplitudes. In this talk the first simulations of orbit excitations will be discussed. The corresponding spin tune shifts will be considered. The influence of the distorted orbit on the polarization build-up caused by the EDM will be examined.
* A. Lehrach, F. Rathmann, J. Pretz et al., "Search for Permanent Electric Dipole Moments at COSY. Step 1: Spin coherence and systematic error studies", 2012

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO058

Study of the “Particle-in-Cell” Induced Noise on High Intensity Beams

emittance, space-charge, synchrotron, resonance

3005

F. Kesting, G. Franchetti
GSI, Darmstadt, Germany
U. Ratzinger
IAP, Frankfurt am Main, Germany

Numerical noise in PIC codes produces artifacts which affects long term beam simulations needed for accelerator as the SIS100. A detailed study on the effect of numerical noise occurring in multi-particle tracking codes is presented. The influence of the granularity of particle distributions and the fineness of the meshes of Poisson solvers on the particle dynamics was studied. These results are used to discuss the effect of the PIC numerical noise in a long term space charge benchmarking study.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO059

Simulation Study on Beam Loss in the Alpha Bucket Regime during SIS-100 Proton Operation

closed-orbit, proton, extraction, synchrotron

3008

S. Sorge
GSI, Darmstadt, Germany

Besides heavy ion operation, the heavy ion synchrotron SIS-100 will accelerate a single proton bunch of N=2*10¹³ particles up to the energy E=29 GeV. For the present standard scenario, optics settings have been developed which provide a transition energy according to gamma_tr=45.5 in order to avoid transition crossing during acceleration. At extraction energy the corresponding nonlinear momentum compaction and phase slip factors cause the formation of a so called alpha bucket. In this contribution we present the results of transverse beam loss tracking studies in the alpha bucket regime. The effects of momentum spread, magnet errors and residual closed orbit distortion are analyzed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO060

Beam-beam Effect on the BTF in Bunched Beams

electron, damping, beam-beam-effects, operation

3011

P.A. Görgen, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
W. Fischer
BNL, Upton, Long Island, New York, USA

We present studies on the transverse baseband Beam Transfer Functions (BTFs) in bunched beams at high energies. The goal of the work is to evaluate whether transverse BTFs can be used to diagnose the tune spread arising from transverse nonlinearities such as the beam-beam effect and space charge. We employ an analytic expression to the BTFs of beams under a transverse nonlinear lens arising from a bi-Gaussian charge distribution. We obtain agreement between a simulation model of an electron-lens like configuration and the analytic results. The tune spread for this scenario can be recovered by means of a fit against the analytic expectation. The results are compared with measurements where the beam-beam effect acts as a substitute for the electron lens. A similar behaviour of the BTF is observed. This allows the conclusion that the transverse BTF can be used to diagnose tune spread from an electron-lens. Finally we discuss the problems that arise when trying to recover the tune spread from BTFs of arbitrary non-Gaussian beams and in the presence of coherent beam-beam modes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO060

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO070

Beam Dynamics Simulations in Cyclotron C230 Considering Imperfections of Magnetic Field Radial Component

cyclotron, proton, acceleration, focusing

3038

E. Samsonov, S.A. Kostromin, N.A. Morozov, E. Syresin
JINR, Dubna, Moscow Region, Russia

Simulations concern to a beam axial motion in the IBA cyclotron C230 that is a base facility in several medical centers worldwide. Because of small axial focusing of the beam in a center of the cyclotron the radial component of magnetic field imperfections leads to additional proton losses. Measured maps of the axial and radial components of magnetic field were used in the simulations. It was found that the radial component with value 5-10 G in the center and approximately 2 G in the main region of acceleration leads to decrease of the resulting beam intensity by about two times and to increase the beam axial width by 25% as well. Simulations define the requirements to the experimental radial component shaping for the next cyclotrons of this series. Providing these requirements will ensure an absence of the additional proton losses due to the axial motion perturbations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO072

Field Parametrisation for the ESS Superconducting Cavities

cavity, linac, space-charge, HOM

3044

T. Lindqvist
Lund University, Lund, Sweden
E. Laface
ESS, Lund, Sweden

Here we present a method for constructing a parametrization of the electric field in the superconducting elliptic cavities of the ESS linac. The parametrization is done by replicating the electric field from measured data using trigonometric and exponential functions. The field generated by the parameters exhibits a mean error of 0.28% ( maximum error of 3.8% and s.t.d. error 1.1%), with the advantage of only taking up a fraction of the required data. The field in the entire cavity is extrapolated by combining the Maxwell equations with the parametrized form of the field. We also present particle simulations based on the parametrization model to showcase some typical accelerator behaviour. Additionally we present a small extension of the parametrization method to also model spoke cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO072

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO073

Longitudinal Acceptance Evaluation from Hamiltonian

cavity, linac, acceleration, lattice

3047

E. Laface
ESS, Lund, Sweden

An RF cavity is designed around a reference particle; if the energy or the phase of a real particle are too far from the reference, the particle is lost. The widest area of energy-phase that allows a particle to be transported by the cavity is called acceptance of the cavity. In simulations the acceptance is evaluated tracking several particles with different energies and phases and marking when a particle is transmitted or lost. This process can be time consuming because of the large amount of tracked particles requested to characterise the cavity acceptance. In this paper we propose an alternative method to evaluate the acceptance studying directly the Hamiltonian associated to the cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO073

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO074

Characterization of the Longitudinal Wakefields in the MAX IV Linac

linac, wakefield, gun, FEL

3050

O. Karlberg, F. Curbis, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

In the second part of 2014, the 3GeV linac at the MAX IV laboratory will enter its commissioning stage. Equipped with two guns, the linac will act as a full energy injector for the two storage rings and at the same time provide high brightness pulses to a Short Pulse Facility (SPF). Compression in the linac is done in two double achromats with fixed R56 that relies upon the RF phase introduced energy chirp, which in this case is strongly enhanced by the longitudinal wakefields. Since the longitudinal wakefields plays a major role in the compression and bunch shaping they need to be carefully investigated during the commissioning. In this proceeding we will discuss a measurement technique that will be used during commissioning to characterize the longitudinal wakefields and their precise effects on e.g. the bunch shape and the energy spread. Predictions obtained from particle tracking will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO074

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO079

Quantitative Analysis of Trapping Probability for Quasi-integrable Two-degree of Freedom Maps

resonance, extraction, coupling, synchrotron

3065

M. Giovannozzi, C. Hernalsteens, J. Williams
CERN, Geneva, Switzerland
A. Bazzani
Bologna University, Bologna, Italy
C. Hernalsteens
EPFL, Lausanne, Switzerland

A key ingredient for the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron is the beam trapping in stable islands of transverse phase space. In a previous paper a method allowing analytical estimation of the fraction of beam trapped into resonance islands as a function of the Hamiltonian parameters has been presented. Such a method applies to one-degree of freedom models of betatronic motion. In this paper, the analysis is extended to the more realistic and challenging case of two-degree of freedom systems, in which the interplay between the horizontal and vertical motion is fully included. Numerical simulations are presented and the results are discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO079

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO081

Simulation and Observation of Driven Beam Oscillations with Space Charge in the CERN PS Booster

space-charge, dipole, quadrupole, focusing

3073

M. McAteer, J.M. Belleman, E. Benedetto, C. Carli, A. Findlay, B. Mikulec, R. Tomás
CERN, Geneva, Switzerland

Funding: This project has been supported by a Marie Curie Early Initial Training Network Fellowship of the European Community's Seventh Framework Programme, contract number (PITN-GA-2011-289485-OPAC).
As part of the LHC Injector Upgrade project, the CERN PS Booster will operate at higher injection and extraction energies and with nearly a factor of two increase in beam brightness. In order to better understand the machine’s limitations, a campaign of nonlinear optics measurements from turn-by-turn trajectory measurements is planned for after Long Shutdown 1. The goal of this work is to establish an efficient procedure for implementing a resonance compensation scheme after the machine’s injection energy is increased. The trajectory measurement system is expected initially to require high intensity beam in order to have good position measurement resolution, so understanding space charge effects will be important for optics analysis. We present the results of simulations of driven beam oscillations with space charge effects, and comparison with trial beam trajectory measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO081

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO082

Observation of Coherent Instability in the CERN PS Booster

quadrupole, closed-orbit, booster, acceleration

3076

M. McAteer, C. Carli, V. Forte, G. Rumolo, R. Tomás
CERN, Geneva, Switzerland

Funding: This project has been supported by a Marie Curie Early Initial Training Network Fellowship of the European Community's Seventh Framework Programme, contract number (PITN-GA-2011-289485-OPAC).
At high intensities and at a certain working point an instability develops in the CERN PS Booster, and large coherent transverse oscillations and beam loss occur. The coherent oscillations and beam loss can be effectively controlled with the transverse damper system, but the origin of the instability is not well-understood. Recent measurements with the PSB's new trajectory measurement system have provided some insight into the nature of this instability, and these observations are presented here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO082

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO083

Weak-strong Beam-beam Simulations for HL-LHC

optics, luminosity, dynamic-aperture, beam-beam-effects

3079

D. Banfi, J. Barranco García
EPFL, Lausanne, Switzerland
T. Pieloni
CERN, Geneva, Switzerland
A. Valishev
Fermilab, Batavia, Illinois, USA

In this paper we present dynamic aperture studies for possible High Luminosity LHC optics in the presence of beam-beam interactions, crab crossing schemes and magnets multipolar errors. Possible operational scenarios of luminosity leveling by transverse offset and betatron function are also studied and the impact on the beams stability is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO083

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO084

Beam Dynamics Observations of Slow Integer Tune Crossing in EMMA

lattice, acceleration, synchrotron, injection

3082

J.M. Garland, H.L. Owen
UMAN, Manchester, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

When the betatron tune is an integer in a cyclical accelerator, dipole-field errors can drive the coherent addition of betatron amplitude to the bunch eventually causing particle loss. Transverse integer tune crossing in a linear non-scaling FFAG is inevitable due to finite chromaticity. In EMMA (Electron Machine with Many Applications), as many as 6 integers may be crossed is as little as 6 turns at maximum acceleration over the 10 – 20 MeV energy range. This fast integer tune crossing, of the order 1 integer per turn, was shown to have little effect on the coherent amplitude growth and charge loss rate. Slower acceleration inside an RF bucket in EMMA allowed the experimental exploration of slower integer tune crossing speeds, of the order of a factor ten slower. The effect on the coherent oscillation amplitude was observed and the charge loss at integer tune crossings indicated resonant effects on the bunch. Simulations in Zgoubi allowed a more detailed analysis and the mechanism of slower resonance crossing in a non-scaling FFAG is discussed, including the importance of coupled longitudinal-transverse decoherence on the effective emittance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO084

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO086

Flat-beam Generation and Compression at Fermilab's Advanced Superconducting Test Accelerator

emittance, quadrupole, laser, dipole

3086

J. Zhu, D. Mihalcea, P. Piot
Fermilab, Batavia, Illinois, USA
D. Mihalcea, P. Piot, C.R. Prokop
Northern Illinois University, DeKalb, Illinois, USA

An important asset of Fermilab’s Advanced Superconducting Test Accelerator (ASTA) is its ability to generate flat beams with high-transverse emittance ratios. In this paper, we present a practical design and simulation of flat beam generation and compression with various bunch charges up to 3.2 nC. Emittance growth within the round-to-flat beam transformer and the impact of low energy compression is discussed in detail. Finally, it is found that the compressed flat beam could provide exciting opportunities in the field of advanced acceleration techniques and accelerator-based light source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO086

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO088

Optimization of the pp AGS Zgoubi Model in the Low Energy Range

resonance, emittance, acceleration, betatron

3089

Y. Dutheil, H. Huang, F. Méot, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
At low energy the AGS lattice is strongly deformed by the two strong helical snakes, required to preserve the polarization. In addition to the complex, highly non-linear field featured by the two snakes, multiple non-linear coupling resonance lines are crossed by the beam in this region. Hence, the use of realistic models for the Siberian snakes is critical for the simulation of the early part of the AGS acceleration cycle. The AGS Zgoubi model uses direct tracking through OPERA field maps of the two snakes. While many processes may be obnoxious to both beam and spin dynamics in this region, it is critical to use a realistic model of the AGS at low energy. This paper presents the current model used and some of the challenges recently faced. We will also compare experimental beam dynamics results to those predicted by the Zgoubi model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO088

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO089

New Tune Jumps Scheme in the Low Energy Part of the AGS Cycle

polarization, resonance, acceleration, hardware

3092

Y. Dutheil, L. Ahrens, J.W. Glenn, H. Huang, F. Méot, V. Schoefer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
During the early part of the acceleration of polarized protons, due to strong optical deformations of the lattice, the tune cannot be placed in the spin gap and the first two vertical intrinsic resonances are crossed. Recent multiparticle trackings using the Zgoubi code show that the spin resonances around Gg=5 could cause as much as 5% loss of polarization. The slow acceleration rate, the two vertical and two horizontal intrinsic spin resonances can contribute to the depolarization in the region. While in the current scheme only the two horizontal intrinsic resonances are jumped, it was proposed to use the tune jumps system to also accelerate the crossing of the two weak vertical intrinsic resonances and improve the polarization transmission through this region. We show the design of this new tune jumps scheme and the expected polarization gains expected from multiparticles Zgoubi simulations. We also compare experimental measurements of the polarization transmission to the Zgoubi simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO089

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO092

Stochastic Noise Effects in High Current PIC Simulation

emittance, space-charge, lattice, solenoid

3101

I. Hofmann, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim, I. Hofmann
GSI, Darmstadt, Germany

The numerical noise inherent to particle-in-cell simulation of 3D high intensity bunched beams is studied with the TRACEWIN code and compared with the analytical model by Struckmeier (1994). The latter assumes the six-dimensional rms emittance or rms entropy growth can be related to Markov type stochastic processes due to temperature anisotropy and the artificial "collisions" caused by using macro-particles and calculating the space charge effect. Our entropy growth confirms the dependency on bunch temperature anisotropy as predicted by Struckmeier. However, we also find noise generation by the non-Liouvillean effect of the Poisson solver grid, which exists in periodic focusing systems even when local temperature anisotropy is absent - contrary to predictions by Struckmeier's model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO094

Large Scale Particle Tracking and the Application in the Simulation of the RFQ Accelerator

rfq, software, emittance, space-charge

3107

L. Du, Q.Z. Xing
TUB, Beijing, People's Republic of China
Y.K. Batygin
LANL, Los Alamos, New Mexico, USA
Y. He, L. Yang
IMP, Lanzhou, People's Republic of China
J. Xu, R. Zhao
IS, Beijing, People's Republic of China

Large scale particle tracking is important for the design and optimization of the Radio-frequency Quadrupole (RFQ) accelerator. In this paper, we present RFQ simulation results of new parallel software named LOCUS3D, which is developed at Institute of Software, Chinese Academy of Sciences. It is based on Particle-In-Cell method and calculates three-dimensional space charge field by an efficient parallel fast Fourier transform method. A RFQ accelerator in Tsinghua University is simulated by tracking 100 million macro particles. This RFQ is designed to accelerate protons from 50 keV to 3 MeV, with peak beam current of 50 mA. As large number of particles been simulated, more accurate and detailed information have been obtained.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO094

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO096

Nonlinear Oscillations of a Sheet Electron Beam

emittance, electron, plasma, brightness

3113

H.Y. Barminova
MEPhI, Moscow, Russia

In collisionless approximation the nonlinear dynamics of continuous strong current intense electron beam is investigated. Nonlinear oscillations of the beam radius appear due to self-consistent nonlinear forces. To study these oscillations the model is used that automatically satisfy to Vlasov equation. The oscillations are described by means of Duffing equation. The equilibrium state is shown to exist. The solutions near the equilibrium state are analyzed. The asymptotic character of the solutions is found. Nonlinear beam transverse oscillations lead to filamentation and effective emittance growth. If particle energy dissipation is absent in the beam transportation channel the physical reason of the effective emittance growth is transfer of the part of the beam potential energy to kinetic energy of the particle transverse oscillations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO096

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO097

Space-charge Neutralization of 750-keV H⁻ Beam at LANSCE

emittance, space-charge, beam-transport, ion

3116

Y.K. Batygin, C. Pillai, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

The injector part of Los Alamos Neutron Science Center (LANSCE) includes 750-keV H⁻ beam transport located upstream of the Drift Tube Linac. Space charge effects play an important role in the beam transport therein. A series of experiments were performed to determine the level of beam space charge neutralization, and time required for neutralization. Measurements performed at different places along the structure indicate significant variation of neutralized space charge beam dynamics along the beamline. Results of measurements were compared with numerical simulations using macroparticle method and envelope equations to determine values of the effective beam current after neutralization, and effective beam emittance, required for beam tuning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO097

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO098

Realistic Modeling of 4-Rod RFQs with CST Studio

rfq, quadrupole, emittance, cavity

3119

S.S. Kurennoy, Y.K. Batygin, E.R. Olivas, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

RFQ accelerators are usually designed and modeled with standard codes based on electrostatic field approximations. There are recent examples when this approach fails to predict the RFQ performance accurately: for 4-rod RFQs 3D effects near the vane ends can noticeably influence the beam dynamics. The same applies to any RFQ where the quadrupole symmetry is broken, e.g., 4-vane RFQ with windows. We analyzed two 201.25-MHz 4-rod RFQs – one recently commissioned at FNAL and a new design for LANL – using 3D modeling with CST Studio. In both cases the manufacturer CAD RFQ model was imported into CST. The EM analysis with MicroWave Studio (MWS) was followed by beam dynamics modeling with Particle Studio (PS). For the LANL RFQ with duty factor up to 15%, a thermal-stress analysis with ANSYS was also performed. The simulation results for FNAL RFQ helped our Fermilab colleagues fix the low output beam energy. The LANL RFQ design was modified after CST simulations indicated insufficient tuning range and incorrect output energy; the modified version satisfies the design requirements. Our PS results were confirmed by multi-particle beam-dynamics codes that used the MWS-calculated RF fields.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO098

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO100

Progresses of the ThomX High Level Control Applications based on MATLAB Middle Layer

betatron, quadrupole, controls, dipole

3125

J.F. Zhang, C. Bruni, I. Chaikovska, S. Chancé, T. Demma, A. Variola
LAL, Orsay, France
A. Loulergue, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France

Funding: Work is supported by the French "Agence Nationale de la Recherche" as part of the program "investing in the future" under reference ANR-10-EQPX-51, and also by grants from Region Ile-de-France.
The Compton back-scattering based compact X-ray source ThomX is under construction in LAL/IN2P3, CNRS, France. This machine will serve as a demonstrator in producing up to 10¹³ ph/s for imaging and cultural heritage recovery. The high level applications of the ThomX machine for the future commissioning and operations are being developed using Matlab Middle Layer (MML) which is broadly used in the modern synchrotron light sources. In this article, we report the nearest progresses of high level applications of the ThomX machine, and present the nonlinear response matrices to correct the tune, chromaticity and orbit, and the algorithm to correct the orbit in the transfer line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO100

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRO112

Beam Dynamics Analysis in the Beam Halo Experiments at IHEP

focusing, experiment, quadrupole, proton

3159

H. Jiang, S. Fu, C. Meng, J. Peng, Y. Zou
IHEP, Beijing, People's Republic of China

We have measured the beam parameters properly, and also found the RMS matched beam. Now we simulate the matched beam and the mismatched beam using the IMPACT and TraceWin code. We find the simulations can succeed to reproduce the beam profiles without halo for both matched and mismatched beam, but there are some differences for the beam with halo.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO112

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME002

Delta-Phi Method for the IFMIF-LIPAc SRF-Linac Cavity Tuning

cavity, linac, SRF, focusing

3205

M. Valette, N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France

In order to achieve the upcoming commissioning of the IFMIF-LIPAc prototype accelerator in Rokkasho, the precision and resolution required for all diagnostics must be determined. These specifications will depend on the precision at which the tuning parameters must be set and finally by the tuning errors that can be tolerated on the beam itself. We will here discuss the use of the ∆φ method to tune the SRF-Linac and the resolution requirements it implies for the BPMs. This method, using a relative time of flight measurement to assess the energy of the beam, has the advantages of allowing setting the beam energy and beam longitudinal focusing at once.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME002

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME007

A Virtual Charge State Separator as an Advanced Tool Coupling Measurements and Simulations

emittance, ion, quadrupole, ion-source

3220

S.G. Yaramyshev, A. Adonin, W.A. Barth, L.A. Dahl, P. Gerhard, L. Groening, R. Hollinger, M.T. Maier, S. Mickat, A. Orzhekhovskaya, H. Vormann
GSI, Darmstadt, Germany

A new Low Energy Beam Transport (LEBT) for multi-charge uranium beam will be built at GSI High Current Injector. All uranium charge states coming from the new ion source will be injected into GSI heavy ion high current HSI-RFQ, but only design ions U⁴⁺ will be accelerated to the final RFQ energy. A detailed knowledge about injected beam- current and -emittance for pure design U⁴⁺ ions is necessary for a proper beam line design commissioning and operation, while the measurements are possible only for a full beam including all charge states. Detailed measurements of beam current and emittance are performed behind the first quadrupole triplet at the beam line. A dedicated algorithm, based on combination of measurements and results of an advanced beam dynamics simulations, provides for an extraction of beam- current and -emittance for only U⁴⁺ component of a beam. The obtained results and final beam dynamics design for the new straight beam line are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME008

New Reference Design of the European ADS RFQ Accelerator for MYRRHA

rfq, emittance, bunching, operation

3223

C. Zhang
GSI, Darmstadt, Germany
H. Podlech
IAP, Frankfurt am Main, Germany

For demonstrating the technical feasibility of nuclear waste transmutation in an Accelerator Driven System (ADS), the MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) proton driver is under intensive studies. Good performance of the 2 – 4 mA, 1.5MeV RFQ (Radio-Frequency Quadrupole), the start of the accelerator chain, is essential to the reliability of the whole facility, so it must be very well designed. On the basis of the first reference design, further improvements with respect to electrode aperture, emittance growths and output distributions have been performed. The simulation results of the new reference design are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME009

Beam Dynamics for the FAIR Proton-Linac RFQ

rfq, linac, bunching, focusing

3226

C. Zhang
GSI, Darmstadt, Germany

The FAIR (Facility for Antiproton and Ion Research) Proton-Linac (P-LINAC) will be started with a 325.224 MHz, 3 MeV Radio-Frequency Quadrupole (RFQ) accelerator. To ensure that a ≥35 mA beam can be injected into the downstream synchrotrons, the design beam intensity of this Proton-RFQ (P-RFQ) has been chosen as 70 mA. Based on the so-called NFSP (New Four-Section Procedure) method, two new beam dynamics designs with varying and constant transverse focusing strength, respectively, have been worked out to meet the latest design requirements using a compact structure. This paper presents the main design concepts and simulation results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME013

Field Optimized 4-rod RFQ Model

rfq, quadrupole, shielding, bunching

3238

J.S. Schmidt, B. Koubek, A. Schempp
IAP, Frankfurt am Main, Germany

The performance of an RFQ in case of its beam quality and transmission is in the basis dependent on the conformity of the field distribution of the manufactured structure with the one of its particle dynamic design. In the last years studies have been performed on the influence of various elements of the 4-rod RFQ on its field distribution. In particular the tuning process of the 4-rod RFQ with its tuning plates has been optimized. These studies have been complemented with detailed simulations on the fringe fields at the end of the electrodes and the conformity of the fields along the structure as well as the influence of other tuning elements like the piston tuner. Based on the findings of this research a proposal for a field optimized 4-rod RFQ model has been developed and will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME013

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME014

Beam Dynamics in the LEBT for FRANZ

rfq, emittance, solenoid, injection

3241

P.P. Schneider, H. Dinter, M. Droba, O. Meusel, D. Noll, T. Nowottnick, O. Payir, H. Podlech, A. Schempp, C. Wiesner
IAP, Frankfurt am Main, Germany

The two Low Energy Beam Transport (LEBT) sections of the accelerator-driven neutron source FRANZ* consist of four solenoids. The first section with two solenoids will match the 120 keV proton beam into a chopper system**. Downstream from the chopper system a second section with two more solenoids will match the beam into the acceptance of the following RFQ. The accelerator will be operated using either a 2 mA dc beam or a pulsed beam with intensities from 50 mA to 200 mA at 250 kHz repetition rate. The high intensity of these ion beams requires the consideration of space-charge effects. Particle simulations with varying parameter sets have been performed in order to determine the settings providing best transmission and beam quality. Loss profiles along the transport channel were computed to identify hotspots. Simulation results for best transmission at lowest emittance growth will be presented.
* O. Meusel et al., Proc. of LINAC12, Tel-Aviv, Israel, MO3A03
** C. Wiesner et al., Proc. of IPAC2012, New Orleans, LA., USA, THPPP074

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME014

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME024

Cooling Design for the FRIB RFQ Cavity at Michigan State University

rfq, cavity, operation, linac

3271

J. Zeng, L. Du, X. Guan, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People's Republic of China
W.Q. Guan, J. Li
NUCTECH, Beijing, People's Republic of China

Funding: Work supported by the Major Research plan of the National Natural Science Foundation of China (Grant No. 91126003)
We present, in this paper, the cooling design for the Radio Frequency Quadrupole (RFQ) cavity of the Facility for Rare Isotope Beams (FRIB) at Michigan State University. The locations and radius of the cooling passages are optimized, which exist in the five-meter-long copper cavity, tuners, dipole-mode stabilizing rods and end-plates. A three-dimensional RF, thermal, and structural analysis by ANSYS has been performed to carry out the design and verify that the present design can meet the requirement for water velocity, stress, deformation and frequency shift.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME024

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME029

Upgrade of Heavy Ion Injector for ITEP-TWAC Facility

ion, acceleration, heavy-ion, focusing

3283

V. Andreev, N.N. Alexeev, A.I. Balabin, M.M. Kats
ITEP, Moscow, Russia
A.A. Metreveli
MEPhI, Moscow, Russia

A new scheme of heavy ion injector I-3 designed for improvement of accelerated beam parameters has been proposed for ITEP-TWAC Facility. It is based on the usage of two quarter-wave double gap resonators operated on 5 MHz with accelerating voltage of 3 MV per gap. Existing 2.5 MHz double gap resonator will be retuned for operational frequency of 5 MHz and new additional one will be built. The new injector optimized for acceleration of heavy ions with A/Z in the range of 3-10 will allow accelerating any ions from C to U with beam current up to10 mA. Results of both electrodynamics and beam dynamics simulations of the accelerating structures are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME029

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME030

Beam Dynamics and Accelerating Cavity Electrodynamics' Simulation of CW 2 MeV Proton RFQ

rfq, linac, cavity, Windows

3286

S.M. Polozov, A.E. Aksentyev, T. Kulevoy
MEPhI, Moscow, Russia

The CW proton linac has a number of important applications; serving as the initial part of a high-energy, high-power linac for an accelerator-driven system is the main of them. Its CW operation mode and a 5-10 mA beam current, however, are limiting factors for the accelerating field. The surface field should not exceed the Kilpatrick field by more than 1.2-1.5 times. This limitation leads to the increase in linac length and beam bunching complexity. The first results of a 2 MeV, 5 mA, CW RFQ, designed for the operating frequency of 162 MHz, are discussed. Beam dynamics simulation results, obtained by using the BEAMDULAC-RFQ code*, are presented. The electrodynamics of the accelerating structure based on the four-vane cavity is discussed. The accelerating cavity design uses coupling windows as was proposed earlier **, but with windows of an elliptical form. Such form allows for better separation of quarupole and dipole modes.
* S.M. Polozov. Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 3 (79), 2012, p. 131-136.
** V.A. Andreev. Patent US5483130, 1996.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME030

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME031

Beam Dynamics Simulation in SC Linac for the Proton Radiotherapy

linac, proton, cavity, focusing

3289

S.M. Polozov, I.A. Ashanin, A.V. Samoshin
MEPhI, Moscow, Russia

Superconducting linear accelerators based on short independently phased SC cavities are widely used today in ADS and FRIB. Such accelerator can be useful as proton therapy beam source*. The accelerator general layout to accelerate proton beam at the energy range 2-240 MeV will detail in this report. Obviously, in this linac will always violate the principle of synchronicity when the synchronous particle velocity is equal to the phase velocity of the accelerating wave and a slipping of particles relative to the accelerating wave. The beam dynamics simulation shows that linac should consist of four groups of identical cavities. Cavities should have phase velocities as βg=0.1, 0.18, 0.3 and 0.49 respectively. The choice of optimum parameters of accelerating cavities and focusing magnets will discussed and the beam dynamics simulation results will presented.
*S.M. Polozov, A.V. Samoshin. Proc. of LINAC’12, pp. 633-635

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME031

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME037

Development of a 72.75 MHz RFQ for the LINCE Accelerator Complex

rfq, quadrupole, Windows, resonance

3304

A.K. Orduz, C. Bonțoiu, I. Martel, A.C.C. Villari
University of Huelva, Huelva, Spain
A. Garbayo
AVS, Elgoibar, Spain
P.N. Ostroumov
ANL, Argonne, Illinois, USA
A.C.C. Villari
FRIB, East Lansing, Michigan, USA

Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA.
Low-energy acceleration for the LINCE project [1] will be achieved using a 72.75 MHz normal conducting four vanes RFQ designed to give a 460 keV/u boost for A/Q = 7 ions in about 5 m. The vanes are modeled to accommodate windows for a clear separation of the RFQ modes and easy fitting to an octagonal resonance chamber. This article presents the main numerical results of the radio-frequency modeling and computational fluid dynamics (CFD). Particle tracking studies optimized for bunching and acceleration are shown as well.
[1] I. Martel et al., “LINCE: A High Intensity Multi-ion Superconducting Linac for Nuclear Structure and Reactions”, IPAC’14, Dresden, Germany, June 2014, THPME036, These Proceedings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME047

Sorting in the ESS

cavity, linac, beam-losses, emittance

3329

S. Peggs, E. Laface, E. Sargsyan, R. Zeng
ESS, Lund, Sweden

Sorting optical elements has significant potential during the construction of superconducting linacs like the ESS, in the same way that it has proved to be very effective in circular accelerators like RHIC and the LHC. In the linac domain, the elements of primary interest are cavities and cryomodules, instead of the magnets (of all sorts) that are routinely sorted in circular accelerators. Multiple cavities can be sorted to optimise individual cryomodules, and cryomodules can be sorted into optimised locations within the tunnel. Different sorting strategies are discussed and preliminarily evaluated in this paper. Central to the evaluation is the identification of goal (or penalty) functions that are maximised (or minimised), and which can be rapidly quantified by simulation. Also crucial is the availability of a modeling system that is realistic in its complex representation of the linac, and which can easily be modified and developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME051

Preparatory Investigations for a Low Frequency Prebuncher at ReA

rfq, linac, bunching, detector

3342

D.M. Alt, J.F. Brandon, D. Leitner, D. Morris, M.J. Syphers, N.R. Usher, W. Wittmer
NSCL, East Lansing, Michigan, USA

The ReA reaccelerator facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) will provide a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. At present the beam repetition rate at the ReA targets is the same as the LINAC RF frequency of 80.5 MHz. A lower frequency would be desirable for many types of experiments using time of flight data acquisitions. Studies were undertaken to investigate possible methods of reducing the beam frequency with minimal reduction in overall beam current. This paper reports the results of preliminary design studies of such a low frequency prebuncher designed to increase the pulse separation and minimize bunch lengths at the detector.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME052

Measurement of the Longitudinal Acceptance of the ReA RFQ

rfq, linac, ion, injection

3346

D.M. Alt, S.W. Krause, A. Lapierre, D. Leitner, S. Nash, R. Rencsok, J.A. Rodriguez, M.J. Syphers, W. Wittmer
NSCL, East Lansing, Michigan, USA

The ReA reaccelerator facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) will provide a unique capability to study reactions with low-energy beams of rare isotopes. A beam from the coupled cyclotron facility is stopped in a gas stopping system, charge bred in an Electron Beam Ion Trap (EBIT), and then reaccelerated in a compact superconducting LINAC. The beam is injected into the LINAC by a room-temperature Radio Frequency Quadrupole (RFQ) combined with an external Multiharmonic Buncher. (MHB) In preparation for future upgrades to the capabilities of the ReA, an accurate determination of the longitudinal acceptance of the RFQ was conducted using a stable ion beam from a test source. This paper presents the results of the acceptance measurement, including empirical confirmation of a predicted asymmetry in the shape of the acceptance window.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME052

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME056

A Space-charge Compatible "Tomography" of Beam Phase-space Distributions

experiment, space-charge, beam-transport, focusing

3358

N. Pichoff
CEA/DSM/IRFU, France
A. Lasheen
CERN, Geneva, Switzerland

The well-known 3-gradient method allows accessing to a beam RMS emittance and Twiss parameters at a position A by measuring its rms size at a downstream position B with at least 3 different transport conditions from A to B. We suggest extending this method to access to a beam phase-space distribution model at A from beam profiles measured at B. We propose to use an iterative method which consists in: - defining a parametric model describing the beam distribution in 4D transverse phase-space at a position A, - adjusting iteratively the model parameters by minimizing the difference between beam profiles measured at B and these obtained by transporting the beam generated according to the model with TraceWIN code from A to B. This method allows taking into account space-charge and other transport non-linearities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME057

Calculations of Halo in TraceWin Code

emittance, diagnostics, linac, beam-losses

3361

N. Pichoff, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France
M. Valette
CEA/IRFU, Gif-sur-Yvette, France

The TraceWIN code is used to simulate the dynamics of the particles and to design linear particle accelerators. The growth of rms emittance along the accelerator is often used to estimate the quality of a design. For high beam powers, the aim is also to limit the production of halo in order to keep particle losses under a requested limit. We present in this article the different ways to quantify this halo in TraceWin.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME069

Performance Studies of the SPS Beam Dump System for HL-LHC Beams

proton, kicker, operation, optics

3394

F.M. Velotti, O. Aberle, C. Bracco, E. Carlier, F. Cerutti, K. Cornelis, L. Ducimetière, B. Goddard, V. Kain, R. Losito, C. Maglioni, M. Meddahi, F. Pasdeloup, V. Senaj, G.E. Steele
CERN, Geneva, Switzerland

The Super Proton Synchrotron (SPS) beam dump system is a concern for the planned High Luminosity LHC (HL-LHC) operation. The system has initially been designed for very different beam parameters compared to those which will reign after the completion of the LHC injectors upgrade, when the SPS will have to operate with unprecedented beam brightness. This paper describes the relevant operational and failure modes of the dump system together with the expected beam loading levels. Tracking studies are presented, considering both normal operation and failure scenarios, with particular attention on the location and level of proton losses. First FLUKA investigations and thermo-mechanical analysis of the high-energy absorber block are described

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME088

Study of Phase Reconstruction Techniques applied to Smith-Purcell Radiation Measurements

radiation, electron, diagnostics, monitoring

3436

N. Delerue, J. Barros, M. Vieille Grosjean
LAL, Orsay, France
O.A. Bezshyyko, V. Khodnevych
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine

Funding: Work supported by the France-Ukraine high energy physics laboratory and by the Université Paris-Sud (programme “attractivité") and the French ANR (contract ANR-12-JS05-0003-01).
Measurements of coherent radiation at accelerators typically give the absolute value of the beam profile Fourier transform but not its phase. Phase reconstruction techniques such as Hilbert transform or Kramers Kronig reconstruction are used to recover such phase. We report a study of the performances of these methods and how to optimize the reconstructed profiles.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME088

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME089

On the Suitability of Longitudinal Profile Measurements using Smith-Purcell Radiation for Short High Current Proton Beams

radiation, proton, detector, optics

3439

J. Barros, N. Delerue, M. Vieille Grosjean
LAL, Orsay, France
I. Dolenc Kittelmann
ESS, Lund, Sweden
C.A. Thomas
Lund University, Lund, Sweden

Funding: Financially supported by the Université Paris-Sud (programme "attractivité") and the French ANR (contract ANR-12-JS05-0003-01).
The use of Smith-Purcell radiation to measure electrons longitudinal profiles has been demonstrated at several facilities in the picosecond and sub-picosecond range. There is a strong interest for the development of non intercepting longitudinal profile diagnostics for high current proton beams. We present here results of simulations on the expected yield of longitudinal profile monitors using Smith-Purcell radiation for such proton beams.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME089

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME090

Fast Luminosity Monitoring using Diamond Sensors for the Super Flavor Factory SuperKEKB

luminosity, scattering, positron, photon

3442

D. El Khechen, P. Bambade, D. Jehanno, C. Rimbault
LAL, Orsay, France

Super luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle . Luminosity optimisation and dynamic imperfections require fast luminosity measurements. The aimed precision, 10^-3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just outside the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed precision and small enough contamination by backgrounds from single-beam particle losses . We will present the results concerning the investigation of the optimal positioning of our diamond sensors, taking into account the rate of Bhabha particles, their interactions with the beam pipe material.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME090

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME101

Considerations for a Cavity-Based Position-Sensitive Heavy Ion Detector for the CR at FAIR

cavity, impedance, ion, heavy-ion

3477

X. Chen, P. Hülsmann, Yu.A. Litvinov, F. Nolden, M.S. Sanjari, M. Steck, T. Stöhlker
GSI, Darmstadt, Germany
X. Chen
Heidelberg University, Heidelberg, Germany
Yu.A. Litvinov
MPI-K, Heidelberg, Germany
J. Piotrowski
AGH University of Science and Technology, Kraków, Poland
T. Stöhlker
HIJ, Jena, Germany

Funding: Work funded by the European Commission (PITN-GA-2011-289485), the Alliance Program of the Helmholtz Association (HA216/EMMI), the Helmholtz-CAS Joint Research Group (HCJRG-108), the BMBF (05E12CD2).
The Facility for Antiproton and Ion Research (FAIR) is a complex yet ongoing project which will allow for a broad range of experimental physics programs as well as a variety of material and medical applications. Being a heavy ion storage ring at FAIR, the Collector Ring (CR) is perfectly suitable for scientific investigations on fundamental properties – such as masses and lifetimes – of short-lived radioactive nuclei when it operates in isochronous mode. To fulfill stringent experimental requirements, a compatible heavy ion detector sensitive to beam intensities and positions is highly demanded. In this paper we present a conceptual design of cavity-based Schottky noise pickup to achieve non-destructive detections of stored particles. Computer-aided simulations follow immediately to justify the feasibility of such a design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME101

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME114

Commissioning and First Beam Measurements with a New Beam Diagnostics for Medical Electron Accelerators

electron, diagnostics, injection, quadrupole

3500

D. Vlad
Siemens AG Healthcare, H CP CV - Components and Vacuum, Erlangen, Germany
G. Fischer
Friedrich-Alexander Universität Erlangen-Nuernberg, University Erlangen-Nuernberg LFTE, Erlangen, Germany
M. Hänel
Siemens Healthcare, Erlangen, Germany

A new beam diagnostics system was developed and built at the Siemens Healthcare Sector facility in Rudolstadt, Germany. The project goal was to develop, commission and operate a complete beam diagnostics system to fully characterize the compact medical linear electron accelerators. An overview of the whole system including the beam diagnostics, linear accelerator and control and supply unit is given. The system was successfully commissioned in July 2013. We report on initial experiences and first experimental results on current measurements, transverse beam size, transverse emittance and momentum and momentum distribution gained during the commissioning phase.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME114

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME119

Transverse emittance measurement at REGAE

emittance, electron, target, diagnostics

3515

S. Bayesteh
Uni HH, Hamburg, Germany
H. Delsim-Hashemi, K. Flöttmann
DESY, Hamburg, Germany

A new linac, named REGAE (Relativistic Electron Gun for Atomic Exploration) has been built at DESY and operates as an electron source for ultra-fast electron diffraction. An RF photocathode gun provides electron bunches of high coherence, sub-pC charge and energies of 2-5 MeV. In order to film time-resolved structural changes of excited specimens, bunch lengths of several femtoseconds need to be created. Taking into account these critical parameters, beam diagnostics at REGAE is very challenging. The existing diagnostics consists of energy, energy spread, beam profile, beam charge and emittance measurements. For transversal diagnostics, specific approaches have to be considered to overcome complications associated with the low charge and to carry out the beam diagnostics in single shot. In this paper, the contribution of the transversal diagnostics to the measurement of the transverse emittance is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME119

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME123

Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

electron, laser, linac, gun

3527

A. Borysenko, E. Hertle, N. Hiller, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, P. Wesolowski
KIT, Karlsruhe, Germany
B. Steffen
DESY, Hamburg, Germany

Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP crystal. Simulations of the electro-optic signal for different operation modes of FLUTE were performed and main challenges are discussed in this talk. This work is funded by the European Union under contract PITN-GA-2011-289191

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME123

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME135

Simulations of the Ion Spatial Distribution in a Gas-Curtain Based Beam Profile Monitor

ion, extraction, electron, antiproton

3563

B.B.D. Lomberg, A. Jeff, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Jeff, B.B.D. Lomberg, V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Jeff
CERN, Geneva, Switzerland
V. Tzoganis
RIKEN Nishina Center, Wako, Japan

Funding: Work supported by the EU under grant agreement 215080 and 289485, HGF and GSI under contract VH-HG-328, the STFC Cockcroft Institute Core Grant No. ST/G008248/1, and a RIKEN-Liverpool studentship.
A gas-jet monitor has been developed and commissioned by the QUASAR Group at the Cockcroft Institute, UK. It is designed to measure the transverse profile of a beam by crossing it with a neutral supersonic gas-jet. An array of high voltage electrodes is used to extract ions from the region where the beam and gas-jet interact. These ions first hit a micro-channel plate (MCP) and are then imaged through a phosphor screen and a CCD camera. It is important to understand and characterise the measured ion distribution in order to extract the beam profile. Therefore, numerical investigations using the commercial COMSOL and OPERA codes were carried out benchmarking profile measurements obtained from a low energy electron beam. This paper presents results from these studies. It compares measurements based on the interaction of the primary beam with the residual gas or the ultra-cold gas curtain, and discusses the comparisons of simulated profiles and extraction field configurations on the measured profile.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME135

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME145

BPM Signal Channel Characterization Test based on TDR for HLS II Storage Ring

storage-ring, impedance, pick-up, electron

3593

J.J. Zheng, C. Cheng, P. Lu, Q. Luo, B.G. Sun, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new BPM system on the upgraded Hefei light source (HLSII) storage ring is installed. Before the machine commissioning, the BPM system should be carefully tested, such as the conductivity and integrity of BPM signal channels from button electrodes to digital beam position processors (pickups, cables and connectors). This paper presents an experience of signal channel test based on time domain reflection (TDR) for HLS II storage ring BPM system. Basing on the wave propagation method, an analytic expression for the signal from TDR on BPM signal channel is briefly introduced. The conductivity and integrity of the BPM signal channels can be verified by comparing the TDR waveform to theory signal. All the BPM signal channels are tested by the TDR in order to verify electronic characteristic and the usability. And some breakdowns are analysed and handled.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME145

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME149

Beam Dynamics Issues in the Post Accelerator for the Rare Isotope Ion Beams from ISOL System in RISP

linac, ion, emittance, ISOL

3605

J.G. Hwang, S.W. Jang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
B.H. Choi, D. Jeon, H.J. Kim, H.J. Kim, I. Shin
IBS, Daejeon, Republic of Korea
L. Lee
KNU, Deagu, Republic of Korea

The accelerator for RISP, which is the superconducting technology based heavy ion linear accelerator construction project, is composed mainly of the driver linac for stable ion beam from an ECR ion source and post linac for unstable ion from an ISOL system. The post accelerator can accelerate the unstable ion beams up to 16.5 MeV/u for 132Sn and 16.0 MeV/u for 58Ni, which has the ratio of mass to charge, A/q, of 8.3. The unstable ion beam such as 132Sn from an ISOL system has the large transverse and longitudinal emittances. Hence acceptance and envelope of the post accelerator should optimize for stable operation. The beam was transported by the post-to-driver transport (P2DT) line which consists of a charge stripper, two charge selection sections and a telescope section with the bunching cavities. In this presentation, we will show the criteria for the design of the post accelerator and result of beam tracking simulation from the low energy transport line to the end of post linac. The initial coordinates of the particles were acquired by the tracking simulation from the low energy beam transport (LEBT) line to the medium energy beam transport (MEBT) line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME149

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME150

Spectrometer for SRF Gun

electron, cavity, dipole, SRF

3608

I.Yu. Vladimirov, V.I. Shvedunov
MSU, Moscow, Russia
T. Kamps, J. Völker
HZB, Berlin, Germany

We report about the design of a spectrometer for energy spectrum measurements of an electron beam generated by a superconducting radio-frequency photoelectron gun (SRF gun), which is under construction at HZB for BERLinPro. The spectrometer shall provide absolute accuracy of energy measurements of about 0.1% and energy resolution about 0.1%. The spectrometer will be also used for single shot phase space measurements in combination with a transverse deflecting cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME150

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME154

Turn-by-turn Beam Profile Study at VEPP-4M

dynamic-aperture, betatron, beam-losses, diagnostics

3620

O.I. Meshkov, E.B. Levichev, P.A. Piminov, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia

The beam dynamics during crossing of dynamical aperture border was studied. We controlled the beam losses and beam transversal profile during high-amplitude betatron oscillations caused by the electrostatic kick. The beam transversal profile was recorded by the Multi Anode Photomultiplier with turn-to turn temporal resolution. The experimental data are compared with numerical simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME154

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME165

Studies into Beam Loss Patterns at European Spallation Source

linac, quadrupole, detector, radiation

3650

M. Jarosz, A. Jansson, L. Tchelidze
ESS, Lund, Sweden

Funding: This project is funded by the European Union under contract PITN-GA-2011-289485.
The linear accelerator of European Spallation Source will produce 5 MW proton beam. Beam of this power will likely generate significant losses along the beamline. To study these losses, a coherent model of the whole machine is being made using custom generator. This model is used to perform Monte Carlo simulations of the propagation of the accelerated beam and the losses in the MARS code system. Preliminary simulations utilizing the uniform beam loss distribution were done. More detailed simulations based on the various different loss patterns focused around hot spots in magnets were also performed and their results compared. This confirmed the limit of 0.5 W/m average heat load on accelerating cavities foreseen by the cooling requirements. Additional studies investigated the dose absorbed by fragile cooling system’s elements during the normal operation of the facility defining their radiation resistance to the levels of few kGy/y. Further simulations will also give the information about the expected beam loss detectors signal at possible locations. These data will be further analysed using custom algorithms.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME165

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME166

System Overview and Current Status of the ESS Beam Position Monitors

linac, electronics, detector, quadrupole

3653

H. Hassanzadegan, A. Jansson, C.A. Thomas
ESS, Lund, Sweden
D. Lipka, M. Werner
DESY, Hamburg, Germany
A. Young
SLAC, Menlo Park, California, USA

It is planned to install more than 140 button BPMs along the ESS linac. The BPMs will be used to measure the beam position and phase in all foreseen beam modes and to provide input to the Machine Interlock System. The phase measurement is mainly intended for cavity tuning and Time-Of-Flight energy measurements. A customized BPM detector based on the European XFEL button style has been designed for the cold linac through a collaboration with DESY. Large buttons with diameters up to 40 mm are foreseen to provide enough S/N ratio not only with the nominal beam, but also with a low-current or a de-bunched beam. A demo MTCA.4 system has been procured and successfully integrated into EPICS. Also, a customized Rear Transition Module for down-mixing the BPM signals will be developed with SLAC. Electronics tests with a BPM test bench are currently going on at ESS. BPM installation in the linac is foreseen for 2017 and afterwards.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME166

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME170

Prospects for Longitudinal Phase-space Measurements at the MAX IV Linac

linac, electron, FEL, extraction

3665

F. Curbis, O. Karlberg, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

Knowing the longitudinal phase space of an electron beam is one of the most important and crucial issues in short-pulses linacs. To achieve this task expensive and rather complicated setups (like transverse deflecting cavities) are usually implemented. The MAX IV 3 GeV linac will be used to inject into two rings and to drive a short pulse facility. Nevertheless, a more deep understanding of the beam quality would be useful especially in view of an upgrade as FEL driver. Another interesting aspect is to evaluate how the double-achromat bunch compressors are performing. We are studying how to implement off-phase acceleration: last part of the linac will be set at zero-crossing phase and the transfer line to the 3 GeV ring could be used as energy spectrometer to retrieve the bunch profile. In the present configuration of the MAX IV linac this procedure will allow to check the bunch length after the first bunch compressor. Since it is work in progress, in this contribution we present a sketch of the measurement and the feasibility of the method will be explored by means of simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME170

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME171

General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN

electron, vacuum, klystron, diagnostics

3668

M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234.
We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME173

Beam-based Measurements of the CPS Wire Scanner Precision and Accuracy

emittance, synchrotron, optics, proton

3674

G. Sterbini, B. Dehning, S.S. Gilardoni, A. Guerrero
CERN, Geneva, Switzerland

During 2013 run a systematic campaign of beam-based measurement on the CERN Proton Synchrotron wire scanners has been performed. In this work we report the conditions of the measurements, we describe the results and their interpretation. The observations are compatible with an emittance relative precision and accuracy respectively better than 2 % and 5 % in the vertical plane for nTOF beams. The present limitations of the system are discussed and possible solutions are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME173

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME174

High-accuracy Diagnostic Tool for Electron Cloud Observation in the LHC based on Synchronous Phase Measurements

cryogenics, electron, operation, synchrotron

3677

J.F. Esteban Müller, P. Baudrenghien, T. Mastoridis, E.N. Shaposhnikova, D. Valuch
CERN, Geneva, Switzerland

Electron cloud effects such as heat load in the cryogenic system, pressure rise and beam instabilities are among the main limitations for the LHC operation with 25 ns spaced bunches. A new observation tool was developed to monitor the e-cloud activity and has been successfully used in the LHC during Run 1 (2010-2012). The power loss of each bunch due to the e-cloud can be estimated using very precise bunch-by-bunch measurement of the synchronous phase shift. In order to achieve the required accuracy, corrections for reflection in the cables and some systematic errors need to be applied followed by a post-processing of the measurements. Results show clearly the e-cloud build-up along the bunch trains and its evolution during each LHC fill as well as from fill to fill. Measurements during the 2012 LHC scrubbing run reveal a progressive reduction in the e-cloud activity and therefore a decrease in the secondary electron yield (SEY). The total beam power loss can be computed as a sum of the contributions from all bunches and compared with the heat load deposited in the cryogenic system. The plan to use this method in the LHC operation is also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME174

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME175

A Beam Gas Vertex Detector for Beam Size Measurement in the LHC

detector, target, injection, luminosity

3680

P. Hopchev, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, M.N. Rihl, V. Salustino Guimaraes, B. Salvant, R. Veness, E. van Herwijnen
CERN, Geneva, Switzerland
A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu
EPFL, Lausanne, Switzerland
R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig
RWTH, Aachen, Germany
R. Matev
Sofia University St. Kliment Ohridski, Faculty of Physics, Sofia, Bulgaria

The Beam Gas Vertex (BGV) detector is foreseen as a possible non-invasive beam size measurement instrument for the LHC and its luminosity upgrade. This technique is based on the reconstruction of beam gas interaction vertices, where the charged particles produced in inelastic beam gas interactions are measured with high-precision tracking detectors. The design studies and expected performance of the currently developed BGV prototype will be presented with an overview given of the associated vacuum, detector, and readout systems. A brief description will be given of the BGV Monte Carlo simulation application, which is based on the LHCb computing framework (Gaudi) and allows simulation studies to be performed and online event reconstruction algorithms to be developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME175

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME177

A Novel Approach to Synchrotron Radiation Simulation

injection, detector, radiation, synchrotron

3687

G. Trad, E. Bravin, A. Goldblatt, S. Mazzoni, F. Roncarolo
CERN, Geneva, Switzerland
G. Trad
LPSC, Grenoble Cedex, France

At the Large Hadron Collider (LHC) at CERN, synchrotron radiation (SR) is used to continuously monitor the transverse properties of the beams. Unfortunately the machine and beam parameters are such that the useful radiation emitted inside a separation dipole, chosen as source, is diffraction limited affecting heavily the accuracy of the measurement. In order to deconvolve the diffraction effects from the acquired beam images and in order to design an alternative monitor based on a double slit interferometer an extensive study of the synchrotron light source and of the optical propagation has been made. This study is based on simulations combining together several existing tools: SRW for the source, ZEMAX for the transport and MATLAB for the "glue" and analysis of the results. The resulting tool is very powerful and can be easily adapted to other synchrotron radiation problems. In this paper the simulation package and the way it is used will be described as well as the results obtained for the LHC and SPS cases.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME177

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME184

Improvement of Beam Imaging Systems through Optics Propagation Simulations

radiation, optics, photon, FEL

3709

B. Bolzon, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
A.S. Aryshev
KEK, Ibaraki, Japan
B. Bolzon, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
B. Bolzon, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
P. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom
P. Karataev, K.O. Kruchinin
JAI, Egham, Surrey, United Kingdom

Optical Transition Radiation (OTR) is emitted when a charged particle crosses the interface between two media with different dielectric properties. It has become a wide-spread method for beam profile measurements. However, there are no tools to simulate the propagation of the OTR electric field through an optical system. Simulations using ZEMAX have been performed in order to quantify optical errors, such as aberrations, diffraction, depth of field and misalignment. This paper focuses on simulations of vertically polarized OTR photons with the aim of understanding what limits the resolution of realistic beam imaging systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME184

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME189

Simulation Studies of Diffraction Radiation

radiation, electron, target, damping

3722

T. Aumeyr, R. Ainsworth, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
M.G. Billing
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland

Transition Radiation (TR) and Diffraction Radiation (DR) are produced when a relativistic charged particle moves through a medium or in the vicinity of a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of TR/DR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using TR or DR. This paper reports on recent studies using Zemax, presenting studies on finite beam sizes and the orientation of the beam ellipse.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME189

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME191

Simulation Results of the FETS Laserwire Emittance Scanner

laser, ion, detector, emittance

3729

K.O. Kruchinin, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
D.C. Faircloth
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) has been developed to demonstrate a high current (60 mA) H⁻ beam with the energy of 3 MeV that will be required for future proton drivers. At such high power beam machine a non-invasive diagnostics is required. To measure the emittance of the ion beam a laserwire scanner is being developed. A high power laser will scan across the H⁻ ion beam. The H⁻ particles will be neutralized via a photo-detachment process producing a stream of fast neutral hydrogen atoms bearing information about the phase space distribution of the initial H⁻ beam. To design an effective detection system and optimize its parameters a simulation of the processes at the interaction point is required. We present recent simulation results of theц FETS laserwire system. Simulations were performed using measured data of the laser propagation and ion beam distribution, obtained with General Particle Tracer code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME191

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI003

Beam-beam Simulation Study for CEPC

luminosity, collider, dynamic-aperture, damping

3763

Y. Zhang
IHEP, Beijing, People's Republic of China
K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

CEPC is an Circular Electron Positron Collider proposed to carry out high precision study on Higgs bosons. It is similar to TLEP project , the luminosity and beam lifetime may be determined by the beamstrahlung effect. We try to check the resonability of the machine parameters with weak-strong and strong-strong simulation. At the same time we also do some cross-check between different codes. We wish the work could help determine the beam parameters which could achieve design luminosity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI003

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI004

FCC-ee/CepC Beam-beam Simulations with Beamstrahlung

luminosity, radiation, photon, collider

3766

K. Ohmi
KEK, Ibaraki, Japan
F. Zimmermann
CERN, Geneva, Switzerland

Beamstrahlung, namely synchrotron radiation emitted during the beam-beam collision, can be an important effect for circular high-energy lepton colliders such as FCC-ee (TLEP). In this paper we study beam-beam effects in the presence of energy spreading and bunch lengthening due to beamstrahlung.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI004

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI007

Lattice Optimization of BEPCII Collider Rings

lattice, luminosity, sextupole, collider

3776

Y. Zhang, Q. Qin, C.H. Yu
IHEP, Beijing, People's Republic of China

BEPCII is a double ring e⁺e⁻ collider operating in the tau-charm region. In March 2013, the peak luminosity achieves 7.0·10³² cm^-2s^-1 with a new lower alphap lattice. The beam-beam parameter is also increased from 0.033 to 0.04 with the new lattice. In this paper we'll review the lattice optimization history briefly and focus on the optimization of the lower alphap lattice.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI007

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI012

Tuning of the Compact Linear Collider Beam Delivery System

luminosity, collider, linear-collider, multipole

3788

Y.I. Levinsen, G. Giambelli, A. Latina, R. Tomás
CERN, Geneva, Switzerland
H. Garcia
UPC, Barcelona, Spain
J. Snuverink
JAI, Egham, Surrey, United Kingdom

Tuning the CLIC Beam Delivery System (BDS), and in particular the final focus, is a challenging task. In simulations without misalignments, the goal is to reach 120~\% of the nominal luminosity target, in order to allow for 10~\% loss due to static imperfections, and another 10~\% loss from dynamic imperfections. Various approaches have been considered to correct the magnet misalignments, including 1-1 correction, dispersion free steering (DFS), and several minimization methods utilizing multipole movers. In this paper we report on the recent advancements towards a feasible tuning approach that reach the required luminosity target in a reasonable time frame.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI012

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI019

Reliability and Availability Modeling for Accelerator Driven Facilities

software, operation, vacuum, linac

3803

O. Rey Orozko, E. Bargalló, A. Nordt
ESS, Lund, Sweden
A. Apollonio, R. Schmidt
CERN, Geneva, Switzerland

Accelerator driven facilities are and will have to be designed to a very high level of reliability and beam availability to meet expectations of the users and experiments. In order to fulfill these demanding requirements on reliability and overall beam availability, statistical models have been developed. We compare different statistical reliability models as well as tools in terms of their performance, capacity and user-friendliness. In addition we also benchmarked some of the existing models. We will present in detail a tool being used for LHC and LINAC4 which is based on the commercially available software package Isograph and a tool using Excel, which was developed in house for ESS-systems. The impact of an early reliability modeling on the design of mission critical systems will be presented as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI032

Study of a RF Gun with a Thermoionic Cathode

gun, cavity, injection, space-charge

3837

A.S. Setty, A.S. Chauchat, D. Fasse, D. Jousse, P. Sirot
Thales Communications & Security (TCS), Gennevilliers Cedex, France

The low energy part of our pre injectors* is made up of a 90 kV DC thermoionic triode gun, followed by a 500 MHz sub harmonic prebuncher and a 3 GHz prebuncher. These two cavities are respectively fed with 500 W, a modulation of ± 25 kV, and 90 W corresponding to a ± 10 kV. The gun grid is modulated within a 500 MHz signal. The initial 1 ns phase extension at the gun level is reduced, at the buncher entry, to 40 ps for 75% of the gun current. This study proposes to replace the gun and the two cavities by a RF gun integrated in a modulated cavity at 200 MHz followed by a drift in order to bunch the beam. This study will compare the beam dynamics simulations for these two cases.
*A. Setty et al, "Design and Construction of Turnkey Linacs as Injectors for Light Sources", Proceedings IPAC 2012, USA, Louisiana, May 2012.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI032

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI033

Design of New Buncher Cavity for Relativistic Electron Gun for Atomic Exploration – REGAE

cavity, emittance, electron, operation

3840

M. Fakhari, H. Delsim-Hashemi, K. Flöttmann, M. Hüning, S. Pfeiffer, H. Schlarb
DESY, Hamburg, Germany
J. Roßbach
Uni HH, Hamburg, Germany

The Relativistic Electron Gun for Atomic Exploration, REGAE, is a small electron accelerator build and operated at DESY. Its main application is to provide high quality electron bunches for time resolved diffraction experiments. The RF system of REGAE contains different parts such as low level RF, preamplifier, modulator, phase shifter, and cavities. A photocathode gun cavity to produce the electrons and a buncher cavity to compress the electron bunches in the following drift tube. Since the difference between the operating mode of the existing buncher and its adjacent mode is too small, the input power excites the other modes in addition to the operating mode which affects the beam parameters. A new buncher cavity is designed in order to improve the mode separation. Furthermore the whole cavity is modeled by a circuit which can be useful especially during the tuning process. Beam dynamics simulations have been performed in order to compare the new designed cavity with the old one which declare that the effects of the adjacent modes on the beam parameters are decreased.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI035

Design and Simulation of Side Coupled Six MeV Linac for X-Ray Cargo Inspection

cavity, coupling, acceleration, electron

3844

S. Ahmadiannamin, F. AbbasiDavani, R. Ghaderi, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

Using in X-ray cargo inspection is one of most applications of linear accelerators. This paper represents design and simulation of Side Coupled Six MeV cavity. The electromagnetic simulation of structure was carried out in the SUPERFISH and CST Microwave studio. 2.3 MW input power is considered according to MG5193 magnetron. The coupling coefficient is calculated equal to 3% for stabilization of accelerator operation against environmental and mechanical errors effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI035

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI038

Simulation Study of Electron Gun for Six MeV Linac for X-Ray Cargo Inspection

electron, gun, cathode, focusing

3847

S. Ahmadiannamin, F. AbbasiDavani, R. Ghaderi, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

Electron guns are designed in different models. Output beam quality and efficiency of the linear accelerator for each application depends on choosing the suitable model of electron gun. The most common types are diode and triode electron guns. Simulation Study of diode electron gun of Six MeV Linac for X-Ray Cargo Inspection represented in this article. Vaughan analytical method was used to obtain the initial dimensions. In final stage, CST Particle Studio software used to obtain the dimensional details.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI038

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI040

Study of Geometrical Parameters and their Tolerances in Optimization of Accelerating Cells of Side Coupled Linac

cavity, linac, impedance, electron

3850

S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
F. AbbasiDavani, S. Ahmadiannamin, F. Ghasemi
sbu, Tehran, Iran
M. Lamehi Rashti
IPM, Tehran, Iran

After choosing the suitable geometry for accelerating cavity, evaluation of geometrical parameters effects on radio frequency characteristics is essential. In this paper after study of priority of geometrical parameters in optimization of accelerating cells of Side Coupled Linac, according to obtained results, new design of s-band accelerating cavity is suggested. By frequency sensitivity study of new dimensions, we can choose best technique to tune the accelerating cavity during magnetic coupling-hole adjustment.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI040

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI045

Development of a 1.3-GHz Buncher Cavity for the Compact ERL

cavity, operation, vacuum, gun

3866

T. Takahashi, Y. Honda, T. Miura, T. Miyajima, H. Sakai, S. Sakanaka, K. Shinoe, T. Uchiyama, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan

In a high-brightness injector of the Compact ERL (cERL), a 1.3-GHz buncher cavity is used to compress the electron bunches which are produced at a 500-kV photocathode DC electron gun. An rf voltage required is about 130 kV. To elongate the lifetime of the photocathode of the DC gun which is located beside the buncher cavity, an extremely-low pressure of about 10^-9 Pa is required in the buncher cavity under operating conditions. In order to achieve such low pressures, we have developed a normal-conducting cavity which included several measures to reduce the outgas from the cavity components, together with careful rf designs to avoid any problems due to multipactor discharges or to other problems. With the developed cavity, we achieved a vacuum pressure of about 2·10^-9 Pa under rf operations at an rf voltage of about 100 kV. The buncher cavity was installed in the cERL, and it worked very well; we could demonstrate to compress the bunch length from 10 ps (FWHM) to 0.5 ps (rms) using the buncher cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI045

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI048

Design of an Accelerating Tube for a Standing-wave Accelerator based on Genetic Algorithm’s Optimal Calculation

impedance, electron, coupling, radiation

3875

Z.X. Tang
USTC, Hefei, Anhui, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

A compact medical standing-wave (SW) electron accelerating tube has been designed that operating frequency is 2998MHz, operating mode is π/2, final energy is 6MeV and beam current is 100mA based on genetic algorithm (GA)’s optimal calculation. It employed a bi-periodic structure with nose cone shape. We performed the simulation experiment which proved that GA was feasible and gave a set of geometric parameter with higher shunt impedance. We performed tuning of the whole tube by CST MICROWAVE STUDIO and SUPERFISH and calculation of beam dynamics by ASTRA and Parmela in this paper. The total length of the tube is less than 300mm.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI048

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI051

Fabrication and Tests of the Re-buncher Cavities for the LIPAc Deuteron Accelerator

cavity, vacuum, pick-up, coupling

3884

D. Gavela, P. Abramian, J. Calero, A. Guirao, J.L. Gutiérrez, E. Molina Marinas, I. Podadera, L. Sánchez, F. Toral
CIEMAT, Madrid, Spain

Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project AIC-A-2011-0654
Two re-buncher cavities will be installed at the Medium Energy Beam Transport (MEBT) of the LIPAc accelerator, presently being built at Rokkasho (Japan). They are IH-type cavities with 5 gaps and will provide an effective voltage of 350 kV at 175 MHz. The cavity consists of a cylindrical main body and two endplates in stainless steel with an internal copper coating. The stems and drift tubes are machined from bulk OFE copper. The fabrication techniques for the cooling pipes, the input coupler and the pick-up are presented. Material choices and fabrication process are discussed. The first re-buncher is already fabricated. RF low power tests have been made to measure resonant frequency, S-parameters and Q-factor before and after the copper plating. The electric field map has also been measured with the bead-pull method.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI051

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI053

Ferrite Material Characterization in a Static Bias Field for the Design of a Tunable Cavity

impedance, cavity, electromagnetic-fields, solenoid

3890

J. Eberhardt, F. Caspers, C. Vollinger
CERN, Geneva, Switzerland

During the development of ferrite-loaded accelerating cavities, the electromagnetic properties of the dispersive ferrite material need to be known. We describe a coaxial short-circuit measurement technique to measure the complex permeability of toroidal-shaped samples (127mm outer and 70mm inner diameter) that are exposed to an external magnetic bias field. The external magnetic bias field is applied perpendicular to the RF magnetic field. With this method it is possible to characterize the frequency dependence of the permeability for a frequency range of 1-100MHz. The dependence of the permeability on the external magnetic bias is presented for the ferrite G-510 from Trans-Tech Inc. and the material characterization is shown in the same frequency range. The measurement results are verified by simulations of the measurement set-up.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI053

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI054

Permittivity and Permeability Measurement Methods for Particle Accelerator Related Materials

impedance, resonance, cavity, HOM

3893

C. Vollinger, F. Caspers, E. Jensen
CERN, Geneva, Switzerland

For the special requirements related to particle accelerators, knowledge of the different material parameters of dielectrics and other materials are needed in order to carry out simulations during the design process of accelerator components. This includes also properties of magnetically biased ferrites of which usually little information is available about material characteristics, especially in magnetic bias fields. Several methods of measurement are discussed and compared of which some require delicate sample preparation whereas others can work with unmodified material shapes that makes those methods also suited for acceptance checks on incoming materials delivered by industry. Applications include characterization of different materials, as absorbers in which dielectric losses play an increasing role, as well as low frequency measurements on ferrites that are used for tunable cavities. We present results obtained from both broadband and resonant measurements on different materials determined in the same sample holder. Where possible, the results were confirmed with alternative methods.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI056

A New Debunching Cavity for the ISIS H⁻ Injector

cavity, vacuum, DTL, radio-frequency

3899

B.S. Drumm, A.P. Letchford, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
M. Keelan
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The energy range of the ISIS 70MeV H⁻ injected beam is reduced using an RF debunching cavity. The existing cavity consists of a mild steel vacuum vessel containing a water-cooled copper shell into which RF power is fed. The unit is made up of components designed for the 50 MeV Proton Linear Accelerator (PLA) which used to occupy the Rutherford Appleton Laboratory (RAL) site between 1957 and 1969. The component drawings date back to the late 1960s. Due to its age, complexity and a lack of spares, there is a need for a modern solution. This paper documents the development of a new debunching cavity for the ISIS neutron source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI056

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI058

RF Delivery System for FETS

rfq, klystron, rf-amplifier, quadrupole

3902

S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
M. Dudman, A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. In this experiment, the first stages necessary to produce a very high quality, chopped H⁻ ion beam as required for the next generation of high power proton accelerators (HPPAs) are designed, built and tested. HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An RF system outline, circulator high power tests, RF amplifiers tests, waveguide run with shielding and couplers design are presented and discussed in this paper. Experimental measurements of the system’s circulator and RF Amplifiers high power test will be presented as part of the system testing results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI058

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI070

Tuner System Simulation and Tests for the 201-MHz MICE Cavity

cavity, controls, vacuum, feedback

3927

L. Somaschini
INFN-Pisa, Pisa, Italy
A.J. DeMello, A.R. Lambert, S.P. Virostek
LBNL, Berkeley, California, USA
J.H. Gaynier, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz
Fermilab, Batavia, Illinois, USA
Y. Torun
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
The frequency of MICE cavities is controlled by pneumatic tuners as their operation is impervious to large magnetic fields. The mechanical and RF transfer functions of the tuner were simulated in ANSYS. The first of these tuning systems was assembled and tested at Fermilab. The mechanical response and the RF tuning transfer function have been measured and compared with simulation results. Finally the failure of different actuators has been simulated and tested to predict the operational limits of the tuner.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI077

Electric Field Enhancement Study using an L-band Photocathode Gun

cathode, gun, experiment, pick-up

3946

J.H. Shao, W. Gai
ANL, Argonne, Illinois, USA
H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

RF breakdown in high gradient accelerating structures is a fundamental problem that is still needed better understanding. Past studies have indicated that field emission, which is usually represented by electric field enhancement (i.e. β) produced from the Fowler-Nordheim plot, is strongly coupled to the breakdown problem. A controlled surface study using a high gradient L-band RF gun is being carried out. With a flat cathode, the maximum electric field on the surface reached 10³ MV/m. And electric field as high as 565 MV/m on the surface was achieved by a pin-shaped cathode. The field enhancement factor was measured at different surface field during the conditioning process. Initial results of the study are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI077

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI079

RF BREAKDOWN IN A GAS-FILLED TE01 CAVITY

cavity, plasma, klystron, electron

3952

F.Y. Wang, C. Adolphsen, C.D. Nantista
SLAC, Menlo Park, California, USA

An L-band (1.3 GHz) TE01 mode pillbox cavity has been designed to study rf breakdown in gas. Since there are no surface electric fields, effects from the electron interaction with the surface should not be present as in the DC breakdown case. A CCD camera was used to measure the integrated light pattern through holes in the cavity, and an ultrafast diode was used to observed the evolution of the plasma during breakdown. Some preliminary results of the tests are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI079

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI080

The New Design for Capture Cavity of CEBAF

cavity, coupling, electron, acceleration

3955

S. Wang, J. Guo, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

In CEBAF, the electron beam from the injector must be sufficiently relativistic to match a 1 GeV recirculated beam in the first linac. The electron beam is produced with a ~130 keV electron gun, then accelerated by a room temperature, graded-beta standing wave linac, capture section, from 130 keV to 510 keV before enters two 5-cell superconducting RF cavities for further acceleration. Present capture cavity is a 5-cell side-coupled cavity. We designed a new slot-coupled cavity which has lower power consumption and simpler structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI080

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI084

Testing Results of the Prototype Beam Absorber for the PXIE MEBT

focusing, radiation, electron, experiment

3967

C.M. Baffes, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. A prototype of the absorber was manufactured from molybdenum alloy TZM, and tested with an electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototype and key testing results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI084

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI093

CSCM: EXPERIMENTAL AND SIMULATION RESULTS

dipole, operation, extraction, network

3988

S. Rowan, B. Auchmann, K. Brodzinski, Z. Charifoulline, R. Denz, V. Roger, I. Romera, R. Schmidt, A.P. Siemko, J. Steckert, H. Thiesen, A.P. Verweij, G.P. Willering, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
H. Pfeffer
Fermilab, Batavia, Illinois, USA

The copper-stabilizer continuity measurement - or CSCM - was devised to obtain a direct and complete qualification of the continuity in the 13 kA bypass circuits of the LHC, especially in the copper-stabilizer of the busbar joints and the bolted connections in the diode-leads. The circuit under test is brought to ~20 K, a voltage is applied to open the diodes, and the low-inductance circuit is powered with a pre-defined series of current profiles. The profiles are designed to successively increase the thermal load on the busbar joints up to a level that corresponds to worst-case operating conditions at nominal energy. In this way, the circuit is tested for thermal runaways in the joints - the very process that could prove catastrophic if it occurred under nominal conditions with the full circuit energy. Surveillance software and a numerical model were devised to carry out the analysis and ensure complete protection of the circuit from over-heating. A type test of the CSCM was successfully carried out in April 2013 on one main dipole and one main quadrupole circuit of the LHC. This paper describes the analysis procedure, the numerical model, and results of this first type test.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI093

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI094

MadX Tracking Simulations to Determine the Beam loss Distributions for the LHC Quench Tests with ADT Excitation

quadrupole, beam-losses, experiment, focusing

3991

V. Chetvertkova, B. Auchmann, T. Bär, W. Höfle, A. Priebe, M. Sapinski, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

Quench tests with stored beam were performed in 2013 with one of the LHC main focusing quadrupoles to experimentally verify the quench levels for beam losses in the time scales from a few milliseconds to several seconds. A novel technique combining a 3-corrector orbital bump and transverse-damper kicks was used for inducing the beam losses. MadX tracking simulations were an essential step for determining the spatial and angular beam loss distributions during the experiment. These were then used as input for further energy-deposition and quench-level calculations. In this paper the simulated beam-loss distributions for the respective time scales and experimental parameters are presented. Furthermore the sensitivity of the obtained loss-distributions to the variation of key input parameters, which were measured during the experiment, is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI094

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRI108

Manufacturing and Inspecting Supporting Tables for Front End in Taiwan Photon Source

synchrotron, synchrotron-radiation, alignment, radiation

4031

P.A. Lin, K.H. Hsu, C.K. Kuan, C.-S. Lin, H.Y. Lin, I.C. Sheng
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source is the second accelerator constructed by National Synchrotron Radiation Research Center with energy 3 GeV and 500 mA beam current. In order to install and support front end components those table are designed and constructed. The results of manufacturing and inspecting tables are one of the primary factors that will directly affect the final confining aperture to the end usres. Those supporting table has six types and are all designed and simulated by Solidworks. Different alignment and measurement tools are utilized to inspect these tables. In addition, some results of final post-installation measurement and vibration test are also reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI108

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)