IPAC2014 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOPRO035	Update on Nonlinear Collimation Schemes for the LHC	collimation, sextupole, simulation, 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
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MOPRO037	Collimator Fast Failure Losses for Various HL-LHC Configurations	collimation, simulation, 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
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MOPRO040	Collimation Cleaning for HL-LHC Optics Scenarios with Error Models	simulation, collimation, alignment, 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
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MOPRO041	Multi-turn Tracking of Collision Products at the LHC	proton, simulation, luminosity, betatron	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
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MOPRO042	Cleaning Performance with 11T Dipoles and Local Dispersion Suppressor Collimation at the LHC	dipole, collimation, simulation, 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
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MOPRO046	Comparison of MERLIN/SixTrack for LHC Collimation Studies	collimation, scattering, simulation, 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
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MOPRO053	Study of Upgrade Scenarios for the SOLEIL Storage Ring	emittance, lattice, dipole, sextupole	203
	R. Nagaoka, P. Brunelle, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Within the scope of a future major upgrade of the SOLEIL storage ring, presently having the energy of 2.75 GeV, the circumference of 354 m and the horizontal emittance of 3.7 nm.rad, towards a Diffraction Limited Storage Ring (DLSR), the present paper presents and discusses the outcomes of a series of studies launched to explore different possible scenarios for the magnet lattice arrangement, under the constraint of making the upgrade in the same existing machine tunnel. Two scenarios were presented earlier in this context, which both preserved all the existing free straight sections for insertions, though the bending magnet positions were not strictly conserved. The purpose of the extended studies is to explore, in particular, the range of horizontal emittance that can be reached by hypothetically removing some of the existing geometric constraints, such as suppressing or shortening partially the straight sections. The emittance range is equally studied by fulfilling rigorously all constraints. The dependence of the nonlinear properties of the magnet lattice on the linear optics is simultaneously investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO053
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MOPRO058	The Low-alpha Lattice and Bunch Length Limits at BESSY-VSR	radiation, storage-ring, coupling, dipole	216
	P. Goslawski, M. Ries, M. Ruprecht, G. Wüstefeld HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin. An upgrade of the BESSY II ring to a Variable bunch length Storage Ring BESSY^VSR has been recently proposed , by introducing strongly focusing superconducting cavities. This will allow to store simultaneously long and short bunches. In the regular user optics, bunch lengths of 15 ps (rms) and down to 1.5 ps (rms) are expected. Bunches as short as 300 fs (rms), close to the bunch length limit, and a ring current of 3.5 mA at the bunch bursting threshold can be provided by using a modified low-alpha optics. This presentation will discuss the properties of the low-alpha optics and intrinsic bunch length limits, given by coupling effects of the longitudinal and horizontal plane. G. Wüstefeld, A. Jankowiak, J. Knobloch, M.Ries, "Simultaneous Long and Short Electron Bunches in the BESSYII Storage Ring", Proceedings of IPAC2011, San Sebastian, Spain.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO058
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MOPRO068	Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation	simulation, synchrotron, storage-ring, operation	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
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MOPRO083	Design Study of High Brilliant Optics at the SPring-8 Storage Ring	emittance, photon, brilliance, electron	283
	Y. Shimosaki, T. Aoki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, H. Ohkuma, M. Shoji, K. Soutome, S. Takano, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	At the SPring-8 storage ring, design study of beam optics concentrating particularly on increasing brilliance, not flux density, is in progress besides continuous efforts of increasing both brilliance and flux density for the user optics. The natural emittances are theoretically reduced from 2.41 nmrad at 8 GeV to 2.27 nmrad (8 GeV), 1.78 nmrad (7 GeV) and 1.33 nmrad (6 GeV) by utilizing an emittance damping effect by the insertion devices. The designed optics has experimentally been examined at 6 GeV, and the electron beam parameters have been confirmed by measurements at the diagnostics beamlines. * Y. Shimosaki et al., “New Optics with Emittance Reduction at the SPring-8 Storage Ring”, IPAC13, MOPEA027.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO083
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MOPRO108	Lattice and Start-to-end Simulation of the Mainz Energy Recovering Superconducting Accelerator MESA	lattice, linac, experiment, simulation	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
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MOPME021	Vicky: Computer Code Update	quadrupole, multipole, undulator, sextupole	421
	F. Iazzourene Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Vicky is a computer code for designing and simulating charged particle accelerators. We recall mainly that Vicky is a very user friendly code, the particle motion is described by 10 parameters: four beta-functions, four alpha-functions and two phase advances, and a large variety of insertion devices, wigglers and undulators, linearly and elliptically polarized, are treated. The features include Twiss functions matching, orbit correction, tune and chromaticity adjustment, dynamic aperture and phase space tracking. The paper describes new aspects and the present status. F. IAZZOURENE, “Vicky: A Computer Code for Use in the Design and Simulation of Particle Accelerators”, proceedings IPAC 2011.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME021
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MOPME040	MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators	dipole, lattice, shielding, database	463
	M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515 Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME040
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MOPRI077	Hi-Lumi LHC Collimation Studies with MERLIN Code	collimation, scattering, proton, simulation	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.
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MOPRI096	The New Transfer Line Collimation System for the LHC High Luminosity Era	injection, collimation, luminosity, extraction	839
	V. Kain, C. Bracco, B. Goddard, F.L. Maciariello, M. Meddahi, A. Mereghetti, G.E. Steele, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	A set of passive absorbers is located at the end of each of the 3 km long injection lines to protect the LHC in case of failures during the extraction process from the LHC’s last pre-injector or the beam transfer itself. In case of an erroneous extraction, the absorbers have to attenuate the beam to a safe level and be robust enough themselves to survive the impact. These requirements are difficult to fulfil with the very bright and intense beams produced by the LHC injectors for the high luminosity era. This paper revisits the requirements for the SPS-to-LHC transfer line collimation system and the adapted strategy to fulfill these for the LHC high luminosity operation. A possible solution for the new transfer line collimation system is presented.
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MOPRI098	Design Studies of the Upgraded Collimation System in the SPS-to-LHC Transfer Lines	collimation, luminosity, injection, simulation	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.
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MOPRI099	Feasibility Studies for 100 GeV Beam Transfer Lines for a CERN Neutrino Facility	target, dipole, quadrupole, focusing	849
	M. Kowalska, W. Bartmann, C. Bracco, B. Goddard, M. Nessi, R. Steerenberg, F.M. Velotti CERN, Geneva, Switzerland
	For a potential future CERN neutrino facility it is considered to extract a 100 GeV proton beam from the second long straight section in the SPS into the existing TT20 transfer line leading to the North Area. Two transfer line design options were developed simultaneously: early-branching from TT20 using existing, recuperated ‘experimental area’ DC dipoles and alternatively late-branching close to the target area, which requires superconducting magnets. This paper describes the feasibility of the two concepts in addition to the detailed study of the early-branching option. Optics and line geometry optimization are discussed and orbit correction is presented.
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MOPRI102	Upgrades of the CERN PS Booster Ejection Lines	emittance, injection, quadrupole, dipole	858
	W. Bartmann, J.L. Abelleira, K. Hanke, M. Kowalska CERN, Geneva, Switzerland
	The PS Booster extraction energy will be augmented from 1.4 to 2 GeV to reduce intensity limits due to space charge at the PS proton injection. For this upgrade the transfer line between PS Booster and PS will be modified for 2 GeV operation and pulse to pulse optics modulation for different beam types. Also the PS Booster measurement line will also be upgraded to 2 GeV and shall provide improved optics solutions for emittance measurements while reducing the loss levels recorded during operation. This paper describes the foreseen optics solutions for both transfer lines.
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MOPRI116	Beam Flattening System based on Non-linear Optics for High Power Spallation Neutron Target at J-PARC	octupole, target, neutron, proton	896
	S.I. Meigo, A. Akutsu, K.I. Ikezaki, M. Ooi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan H. Fujimori KEK/JAEA, Ibaraki-Ken, Japan
	In the Japanese Spallation Neutron Source (JSNS) of J-PARC, a mercury is utilized as a target material. Since a serious pitting erosion was found at the target vessel at SNS in ORNL and JSNS, a reduction of a peak current density is required. In order to decrease the peak, we have developed the beam optics based on a non linear using an octupole magnets. In a design calculation, it is found that the peak current density of 30 % can be reduced by introducing the octupole magnets. A status of the design and the experimental results will be reported.
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TUOBA02	Design Study of an ERL Test Facility at CERN	electron, cryomodule, cavity, linac	921
	E. Jensen, C. Bracco, O.S. Brüning, R. Calaga, N. Catalán Lasheras, B. Goddard, R. Torres-Sanchez, A. Valloni CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom
	The modern concept of an Energy Recovery Linac allows providing large electron currents at large beam energy with low power consumption. This concept is used in FEL’s, electron-ion colliders and electron coolers. CERN has started a Design Study of an ERL Test Facility with the purpose of 1) studying the ERL principle, its specific beam dynamics and operational issues, as relevant for LHeC, 2) providing a test bed for superconducting cavity modules, cryogenics and integration, 3) studying beam induced quenches in superconducting magnets and protection methods, 4) providing test beams for detector R&D and other applications. It will be complementary to existing or planned facilities and is fostering international collaboration. The operating frequency of 802 MHz was chosen for performance and for optimum synergy with SPS and LHC; the design of the cryomodule has started. The ERL Test Facility can be constructed in stages from initially 150 MeV to ultimately 1 GeV in 3 passes, with beam currents of up to 80 mA. Parameters to serve the above-mentioned purposes are well defined and possible lattice designs have well advanced.
	Slides TUOBA02 [14.419 MB]
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TUPRO001	Alternative High Luminosity LHC Matching Section Layout	injection, quadrupole, luminosity, cavity	990
	B. Dalena, A. Chancé CEA/IRFU, Gif-sur-Yvette, France R. De Maria 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. In the framework of the HL-LHC Upgrade project possible variants for the layout of the LHC matching section located in the high luminosity insertions are investigated. This layout is optimized to reduce the demand on the voltage of the crab cavities, it also improves the optics squeeze-ability, both in ATS[1] and non-ATS mode. Moreover the injection and transitions to collision optics are also discussed. [1] S. Fartoukh, ‘’An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade’’, in proceedings of IPAC11, p. 2088.
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TUPRO003	Fast Crab Cavity Failures in HL-LHC	operation, simulation, 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.
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TUPRO008	Specification of Field Quality of the Interaction Region Magnets of the High Luminosity LHC Based on Dynamic Aperture	lattice, injection, quadrupole, dipole	1013
	Y. Nosochkov, Y. Cai, M.-H. Wang SLAC, Menlo Park, California, USA R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh CERN, Geneva, Switzerland
	Funding: Work partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404, and by the US LARP through US Department of Energy. The high luminosity LHC upgrade (HL-LHC) requires new magnets in the low-beta interaction regions with a larger aperture than in the existing LHC. These include the Nb3Sn superconducting (SC) inner triplet quadrupoles, Nb-Ti SC separation dipoles D1 and D2, and SC matching quadrupoles Q4 and Q5. The large aperture is necessary for accommodating the increased beam size caused by significantly higher beta functions in these magnets in the collision optics. The high beta functions also enhance the effects of field errors in these magnets leading to a smaller dynamic aperture (DA). It is, therefore, critical to determine the field quality specifications for these magnets which 1) satisfy an acceptable DA, and 2) are realistically achievable. The estimates of expected field quality obtained from magnetic field calculations and measurements were used as a starting point. Then, based on the DA study, the field errors were optimized in order to reach an acceptable DA. The DA calculations were performed using SixTrack. Details of the optimization process and summary of the field quality specifications for collision and injection energies are presented.
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TUPRO011	New Tools for K-modulation in the LHC	quadrupole, injection, collider, controls	1024
	M. Kuhn, B. Dehning, V. Kain, R. Tomás, G. Trad CERN, Geneva, Switzerland
	For many applications, the precise knowledge of the beta function at a given location is essential. Several measurement techniques for optics functions are used in the LHC to provide the most suitable method for a given scenario. A new tool to run k-modulation measurements and analysis is being developed with the aim to be fully automatic and online. It will take constraints of various systems such as tune measurement precision, powering limits of the LHC superconducting circuits and limits of their quench protection systems into account. It will also provide the possibility to sinusoidally modulate the currents of the investigated quadrupoles with a predefined frequency and amplitude to increase the measurement precision further. This paper will review the advantages and limitations of k-modulation measurements in the LHC with and without sinusoidal current modulation. The used algorithms and tools will be presented and estimates on the obtainable beta function measurement precision will be given.
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TUPRO018	Prospects for the LHC Optics Measurements and Corrections at Higher Energy	coupling, software, GUI, quadrupole	1046
	R. Tomás, T. Bach, J.M. Coello de Portugal, V. Kain, M. Kuhn, A. Langner, Y.I. Levinsen, K.S.B. Li, E.H. Maclean, N. Magnin, V. Maier, M. McAteer, T. Persson, P.K. Skowroński, R. Westenberger CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom S.M. White BNL, Upton, Long Island, New York, USA
	LHC will resume operation in 2015 at 6.5 TeV. The higher energy allows for smaller IP beta functions, further enhancing the optics errors in the triplet quadrupoles. Moreover the uncertainty in the calibration of some quadrupoles will slightly increase due to saturation effects. The complete magnetic cycle of the LHC will take longer due to the higher energy and extended squeeze sequence. All these issues require more precise and more efficient optics measurements and corrections to guarantee the same optics quality level as in 2012 when a 7% peak beta-beating was achieved. This paper summarizes the on-going efforts for achieving faster and more accurate optics measurements and corrections.
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TUPRO020	Integration of a Neutral Absorber for the LHC Point 8	luminosity, dipole, operation, injection	1052
	A. Santamaría García, R. Alemany-Fernández, H. Burkhardt, F. Cerutti, L.S. Esposito, N.V. Shetty CERN, Geneva, Switzerland
	The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of L = 1-2 . 10³³ cm^-2 s⁻¹, with a pileup of 5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.
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TUPRO022	Implementation of Luminosity Leveling by Betatron Function Adjustment at the LHC Interaction Points	luminosity, experiment, operation, betatron	1058
	J. Wenninger, A.A. Gorzawski CERN, Geneva, Switzerland
	Growing expectations for integrated luminosity during upcoming LHC runs introduce new challenges for LHC beam operation in the scope of online luminosity control. Because some LHC experiments are limited in the maximum event rates, their luminosity is leveled to a constant value. Various techniques may be used for luminosity leveling, changing the betatron function at the interaction point is one of them. This paper explains the main operational requirements of a betatron function leveling scheme for the upcoming LHC run. Issues concerning the beam optics, orbits and collimator settings are discussed. The proposed architecture for control system integration will be discussed. A few operational scenarios with different beam configurations foreseen for the next LHC run will be presented.
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TUPRO024	Benchmarking Studies of Intra Beam Scattering for HL-LHC	lattice, luminosity, injection, scattering	1064
	D. Angal-Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A. Wolski The University of Liverpool, Liverpool, United Kingdom A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404 The effects of Intra Beam Scattering (IBS) in the High Luminosity upgrade of the LHC (HL-LHC) will be stronger compared to effects in the present LHC because of the high intensity of the proton bunches and the new proposed optics. We present benchmarking studies carried out for the present LHC at injection and collision energies as well as HL-LHC at collision energy with the Achromatic Telescopic Squeezing optics. The results of IBS growth-rate calculations using the full Bjorken-Mtingwa formulae* are compared with simplified formulae, Bane’s high energy approximation, and the completely integrated modified Piwinski approximation**. The results of calculations based on these methods carried out in Mathematica are compared with results from the codes MAD-X and ZAP. J. Broken and S. Mtingwa, Part. Accel. 13, 115 (1983) K. Kubo et al, PRST-AB, 8, 081001 (2005) * K. Bane, EPAC2002 **** S. Mtingwa and A. Tollestrup, Fermilab-Pub-89/224, 1987.
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TUPRO041	Status of Ion-optical Design of the Collector Ring	antiproton, quadrupole, injection, kicker	1114
	O.E. Gorda, A. Dolinskyy, S.A. Litvinov GSI, Darmstadt, Germany D.E. Berkaev, I. Koop, P.Yu. Shatunov, D.B. Shwartz BINP SB RAS, Novosibirsk, Russia
	The Collector Ring at FAIR will be used for fast cooling of hot antiproton or ion beams. The ring layout as well as the injection and extraction scheme have been modified during the latest design stage. In this paper, we report on the present status of the ion-optical properties of the machine.
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TUPRO042	Ion Optics of the HESR Storage Ring at FAIR for Operation with Heavy Ions	ion, heavy-ion, target, experiment	1117
	O.A. Kovalenko, A. Dolinskyy, T. Katayama, Yu.A. Litvinov, T. Stöhlker GSI, Darmstadt, Germany B. Lorentz, R. Maier, D. Prasuhn, H. Stockhorst FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) of the FAIR project is primarily designed for internal target experiments with stored and cooled antiprotons, which is the main objective of the PANDA collaboration. However, the HESR storage ring also appears to have remarkable properties to carry out physics experiments with heavy ions. In this paper a new ion optical design allowing the heavy ion operation mode of the HESR is presented. The main goal was to provide an optics which meets the requirements of the future experiments with heavy ion beams. Closed orbit correction, dynamic aperture as well as other characteristics of beam dynamics of the ion optical setup are under analysis in this study.
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TUPRO049	Layout and Optics of the Dump Line at the European XFEL	extraction, kicker, quadrupole, septum	1138
	N. Golubeva, V. Balandin, W. Decking DESY, Hamburg, Germany
	The purpose of the optical system, which we call the dump line, is not simply the transport of the beam to the beam dump. It is an essential part of the beam switchyard which provides the possibility to distribute electron bunches of one beam pulse to different FEL beam lines, allowing a flexible selection of the bunch pattern at each FEL experiment. In this paper we describe the final layout of this optical system as it is now under construction.
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TUPRO050	Measurements of the Optical Functions at FLASH	quadrupole, linac, controls, coupling	1141
	J. Zemella, T. Hellert, M. Scholz, M. Vogt DESY, Hamburg, Germany
	In 2013 the superconducting soft x-ray Free Electron Laser FLASH at DESY (Hamburg, Germany) the extraction section needed to connect the 2nd beam line FLASH2 was installed. In order to allow simultaneous operation of the two beam lines (FLASH1/2), the optical functions in the extraction area needed to be modified. During the recommissioning of FLASH we have optimized, measured and corrected the optical functions in the machine. We report on the the results and the methods.
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TUPRO056	Merit Functions for the Linac Optics Design for Colliders and Light Sources	emittance, focusing, linac, quadrupole	1159
	S. Di Mitri, M. Cornacchia Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy H.-S. Kang PAL, Pohang, Kyungbuk, Republic of Korea
	Optics matching and transverse emittance preservation are key goals for a successful operation of modern high brightness electron linacs. The capability of controlling them in a real machine critically relies on a properly designed magnetic lattice. Conscious of this fact, we introduce an ensemble of optical functions* that permit to solve the often neglected conflict between strong focusing, typically implemented to counteract coherent synchrotron radiation and transverse wakefield instability, and distortion of the transverse phase space induced by chromatic aberrations and focusing errors. A numerical evaluation of the merit functions is applied to existing and planned linac-based free electron lasers. *S. Di Mitri and M. Cornacchia, Nucl. Instr. Meth. Phys. Research A 735, 60–65 (2014).
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TUPRO058	Lattice Correction Modeling for Fermilab IOTA Ring	lattice, closed-orbit, dipole, insertion	1165
	A.L. Romanov BINP SB RAS, Novosibirsk, Russia G.T. Kafka, S. Nagaitsev, A. Valishev Fermilab, Batavia, Illinois, USA
	The construction of the Integrable Optics Test Accelerator (IOTA) is underway at Fermilab. Among the main goals of the facility are the proof-of-principle experiments on nonlinear integrable optics and optical stochastic cooling. Both require outstanding quality of the linear lattice and closed orbit. Software was developed to thoroughly test the proposed lattice configurations for error correction performance. The presented analysis is based on a statistical approach on a number of error seeds, such as various alignment, calibration and field errors.
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TUPRO060	First Turn-by-turn Measurements for Beam Dynamics Studies at ALBA	kicker, injection, electron, sextupole	1171
	Z. Martí, G. Benedetti, M. Carlà, A. Olmos CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	This paper summarizes the tasks carried out to develop a turn-by-turn (TBT) measurement system at ALBA. These tasks mainly include testing the MAF firmware for the libera BPMs and implementing the necessary analytical tools to infer the beam dynamics parameters. TBT measurements using an injection kicker are presented. Linear and non-linear beam dynamics results are compared with LOCO. Results are still preliminary since a good agreement with the linear model has not been achieved yet.
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TUPRO062	Improvements in the Optics Measurement Resolution for the LHC	simulation, 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.
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TUPRO063	Upgrade of Slicing and Tracking in MAD-X	quadrupole, dipole, lattice, sextupole	1180
	H. Burkhardt, L. Deniau, A. Latina CERN, Geneva, Switzerland
	We describe the extension of the functionality of the slicing module and its applications in MAD-X. We can now select thick or thin slicing for individual quadrupoles or groups of quadrupoles and implemented tracking of thick quadrupoles and dipoles in MAD-X. Complex dipole magnets with fringe fields can now automatically be translated to simple bends with extra dipedges.
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TUPRO067	Beam Transport Optimization Studies of the PSI MW-Class Proton Channel	target, proton, simulation, 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.
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TUPRO068	Commisioning of the 2.4T Multipole Wiggler and the 6.5T Superconducting Wavelength Shifter at the SIAM Photon Source	emittance, betatron, storage-ring, operation	1192
	P. Sudmuang, S. Klinkhieo, P. Klysubun, S. Kongtawong, S. Krainara, N. Suradet, A. Tong-on SLRI, Nakhon Ratchasima, Thailand
	A 2.4 T hybrid multipole wiggler (MPW) and a 6.5 T superconducting wavelength shifter (SWLS) have been successfully installed and commissioned at Siam Photon Source (SPS). The influence of the two insertion devices on the electron beam dynamic at different operating points have been studied in order to determine the optimal lattice configuration for operation. In this paper, the compensation of the linear optics will be presented, and the commissioning scheme will also be described. In addition, the investigation of the difference between the model and the actual observed machine parameters will be reported in details.
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TUPME026	TMCI Thresholds for LHC Single Bunches in the CERN-SPS and Comparison with Simulations	impedance, simulation, 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.
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TUPME045	Development of a High-Energy Short-pulse 5-μm Parametric Source for Dielectric Laser Acceleration	laser, acceleration, detector, operation	1460
	G. Xu, I. Jovanovic, S.F. Wandel Penn State University, University Park, Pennsylvania, USA
	A compact, high-peak-power 5-μm laser source with pulse duration of sub-100 fs has been designed and being constructed for pumping a dielectric photonic structure to produce an acceleration gradient of order GV/m in dielectric laser acceleration. Breakdown of dielectric structure induced by multiphoton ionization can be mitigated by adopting long wavelength driver laser. Since the dielectric structure scales with the laser wavelength, fabrication tolerances for dielectric structure are relaxed as well. The 5-μm laser source is based on two cascaded optical parametric amplifiers (OPA): a 2-μm BBO OPA with a mixed phase matching scheme is used as a pump source, and a type-I phase-matched ZGP OPA is designed to produce sub-mJ, <100 fs 5-μm laser pulses. The two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~2.2 mJ with a pulse duration of 42 fs (~6 optical cycles), and excellent pulse stability and beam quality. Preliminary result of ~50 μJ pulse energy at 5-μm is demonstrated by using single-stage ZGP OPA, and an improved two-stage OPA scheme for production of higher pulse energy at 5-μm is under development.
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TUPRI005	nuSTORM Horn Optimization Study	target, simulation, 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.
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TUPRI026	MAX IV Emittance Reduction and Brightness Improvement	emittance, storage-ring, brightness, lattice	1615
	S.C. Leemann, M. Eriksson MAX-lab, Lund, Sweden
	With MAX IV construction well underway and storage ring commissioning expected to commence in July 2015, first studies have been launched to improve the optics of the MAX IV 3 GeV storage ring with the goal of further reducing the emittance from the baseline design (328 pm rad) towards 150 pm rad while improving the matching of the electron beam to insertion devices to further improve the resulting photon brightness. We report on progress in the development of this new optics taking into account the strong impact from intrabeam scattering and insertion devices on the resulting equilibrium emittance. We present initial results and sketch a path towards a first MAX IV upgrade.
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TUPRI081	Feed-forward and Feedback Schemes applied to the Diamond Light Source Storage Ring	feedback, photon, storage-ring, undulator	1757
	M.T. Heron, M.G. Abbott, M.J. Furseman, D.G. Hickin, E.C. Longhi, I.P.S. Martin, G. Rehm, W.A.H. Rogers, A.J. Rose, B. Singh DLS, Oxfordshire, United Kingdom
	Since initial operation for users in Jan 2007, Diamond Light Source has developed to support a suite of 22 experimental stations. These stations have resulted in the installation of 24 undulators and two superconducting wigglers in the storage ring. To preserve optics, tune and coupling with the operation of these devices has necessitated the implementation of a number of feed-forward and feedback schemes. The implementation and operation of these correction schemes will be described.
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TUPRI082	Active Optics Stabilisation Measures at the Diamond Storage Ring	injection, quadrupole, feedback, storage-ring	1760
	I.P.S. Martin, R. Bartolini, R.T. Fielder, M.J. Furseman, E.C. Longhi, G. Rehm, W.A.H. Rogers, A.J. Rose, B. Singh DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	The Diamond storage ring is currently operated with 26 insertion devices (IDs), including 14 in-vacuum IDs, 7 APPLE-II type helical undulators and 2 superconducting wigglers. Differences in the design, construction and operation of these devices, combined with different Twiss parameters at the source point, mean each has a different impact on tune stability and beta-beat. In turn, these parameters affect the on and off-momentum dynamic aperture and ultimately impact on the injection efficiency and lifetime. Another source of optics variation arises from the coherent tune shift with current, which when injecting from zero current causes the tune to span the available good-tune region. In this paper we discuss the difficulties of operating the Diamond storage ring in top-up mode with these effects, and present the various measures taken to stabilise the storage ring optics.
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TUPRI083	A Fast Optics Correction for the Diamond Storage Ring	quadrupole, storage-ring, emittance, feedback	1763
	I.P.S. Martin, M.G. Abbott, R. Bartolini, M.J. Furseman, G. Rehm DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	Since March 2013, the Diamond storage ring has been operated with a target vertical emittance of 8 pm.rad. This condition is achieved by first applying a LOCO* optics correction with IDs set to their typical gaps, then offsetting the skew quadrupole magnets in order to increase the vertical emittance again to the desired value. Whilst a feedback application** is able to stabilise the vertical emittance during ID gap and phase changes in the short to medium term, regular applications of LOCO are still required to maintain good coupling control in the longer term. In this paper we describe measures taken to speed up the optics correction procedure, including a fast orbit response matrix measurement, a reduction of the number of magnets used to measure the data, and a distribution of the LOCO calculations to run in parallel. * J. Safranek, Nucl. Inst. Meth. A, 338, (1997) ** I.P.S. Martin, et al., IPAC 2013, MOPEA071, www. JACoW.org
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TUPRI086	Feedback System Design Techniques for Control of Intra-bunch Instabilities at the SPS	feedback, electron, controls, damping	1769
	C.H. Rivetta, J.M. Cesaratto, J.E. Dusatko, J.D. Fox, O. Turgut SLAC, Menlo Park, California, USA W. Höfle, G. Kotzian, K.S.B. Li 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). The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. This paper presents model-based design techniques for feedback systems to address the stabilization of the transverse bunch dynamics. These techniques include in the design the effect of noise and signals perturbing the bunch motion. Different controllers are compared based on stability margins and equivalent noise gain between input-output of the processing channel. The controller design uses as example the bunch dynamics defined by the SPS ring including the Q20 optics.
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WEOBA03	Status of Preparations for a 10 μs Laser-Assisted H⁻ Beam Stripping Experiment	laser, experiment, ion, injection	1864
	S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A.P. Shishlo, Y. Wang ORNL, Oak Ridge, Tennessee, USA F.G. Garcia, N.F. Luttrell UTK, Knoxville, Tennessee, USA D.E. Johnson Fermilab, Batavia, Illinois, USA A. Rakhman ORNL RAD, Oak Ridge, Tennessee, USA Y. Takeda KEK, Ibaraki, Japan
	Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation. The concept of laser-assisted H⁻ stripping, originated over three decades ago, was successfully demonstrated for a 6 ns, 900 MeV H⁻ beam in 2006. Plans are underway to build on this foundation by performing laser-assisted H⁻ stripping of a 10 μs, 1 GeV H⁻ beam at the Spallation Neutron Source facility; this constitutes a three orders of magnitude improvement over the initial proof of principle demonstration. The central theme of the experiment is the reduction of the required laser power through ion beam manipulations and laser-ion beam temporal matching. This paper discusses the configuration of the experiment, the current and anticipated challenges, and the schedule.
	Slides WEOBA03 [2.549 MB]
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WEZA01	Towards an International Linear Collider: Experiments at ATF2	emittance, sextupole, quadrupole, feedback	1867
	K. Kubo KEK, Ibaraki, Japan
	For linear colliders, realizing extremely small and stable beam is essentially important. At ILC (International Linear Collider), designed vertical beam size and required position stability at the interaction point is nanometer level. In ATF (Accelerator Test Facility) at KEK, study of the final focus system has been performed using small emittance beams extracted from the damping ring. The project is called ATF2. The ATF2 beam line is designed as a prototype of the final focus system of ILC, with basically the same optics, similar beam energy spread, natural chromaticity and tolerances of magnetic field errors. Its design, construction and operation have been performed as an international collaboration. We have demonstrated the local chromatic correction method, which will be used in ILC, and observed the vertical beam size about 55 nm. Test and demonstration of intra-pulse orbit feedback has been successfully performed in the middle of the ATF2 beam line. For demonstration of nm level stable beam, high resolution beam position monitors were installed around the focal point. Here, we report our achievement, status and future plans.
	Slides WEZA01 [1.453 MB]
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WEYB01	Large Dynamic Range Beam Diagnostics for High Average Current Electron LINACs	linac, diagnostics, FEL, brightness	1900
	P.E. Evtushenko JLab, Newport News, Virginia, USA
	A number of applications is envisioned now for CW electron LINACs with high average current. A few examples are: driver-accelerators for the next generation of high average brightness SR sources, energy recovery LINACs to be used for frontier research in particle physics - search for dark matter candidate particles, industrial and defense applications. An average beam power of MWs is considered for such applications. Such machines will be required to operate simultaneously with high beam power and peak brightness comparable to the brightest electron beams generated in pulsed LINACs. Combining the high current advantages of storage rings and high peak brightness of LINACs will require such understanding and control of the beam dynamics that 10^-6 fraction of the beam current is taken in to account and controlled during the beam tuning. To make this possible a number of large dynamic range (LDR) (~10⁺⁶) beam diagnostics is under development and test at JLab FEL. Transverse and longitudinal LDR beam profile measurements can be used for LDR measurements of the phase space distribution and its evolution through the accelerator.
	Slides WEYB01 [4.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEYB01
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WEPRO006	Beam-driven Terahertz Source based on Open Ended Waveguide with a Dielectric Layer	radiation, vacuum, wakefield, experiment	1949
	A.V. Tyukhtin, S.N. Galyamin, V.V. Vorobev Saint-Petersburg State University, Saint-Petersburg, Russia S.P. Antipov Euclid TechLabs, LLC, Solon, Ohio, USA S. Baturin LETI, Saint-Petersburg, Russia
	Funding: Work is supported by the Grant of the President of Russian Federation (MK-273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258). Electromagnetic waves with frequencies from 0.1 THz to 10 THz (usually called the Terahertz gap) are of great importance for a number of scientific and practical applications. Different techniques are known allowing generating these frequencies. However, a current trend of physics and industry is to fill this gap with more powerful and efficient sources. For example, recent experiments have shown promising THz generation in dielectric loaded structures. Developing this area, we consider the THz emitting scheme where an ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation. The end of the waveguide is supposed to be either orthogonal to the structure axis or skewed. To obtain THz frequencies from waveguides with centimeter or millimeter radii, we consider high order modes. We present typical field patterns (in the Fraunhofer zone) and show that the aperture of the vacuum channel gives, as a rule, the main contribution. We also give simple expressions for the angle of the main pattern lobe. S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012).
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WEPRO073	The ESS High Energy Beam Transport after the 2013 Design Update	target, dipole, linac, quadrupole	2121
	H.D. Thomsen, S.P. Møller ISA, Aarhus, Denmark
	Following an optimization of the European Spallation Source (ESS) linac, a number of changes have been introduced in the High Energy Beam Transport (HEBT). In particular, about 120 m of beam transport has been allocated to enable an extension of the superconducting linac, thus providing some contingency against poor linac performance and potentially allowing a future beam power upgrade. The changes in layout and beam optics in all HEBT lines will be discussed.
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WEPRO074	Performance of the ESS High Energy Beam Transport under Non-nominal Conditions	target, quadrupole, dipole, simulation	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.
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WEPRO096	X-ray Radiation Source for Low Dose Angiography based on Channeling Radiation	radiation, electron, photon, cavity	2186
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia
	Angiography is one of the most reliable and contemporary procedure of the vascular system imaging. X-ray spectrums provided by all modern medical angiographs are too broad to acquire high contrast images and provide low radiation dose at the same time. The new method of narrow X-ray spectrum achieving is based on the idea of channelling radiation application. The X-ray filters used in this method allows eliminating the high energy part of the spectrum and providing dramatic dose reduction. The scheme of the facility including the X-ray filter is discussed. The results of the spectrum analysis for the channelling radiation source and typical angiography X-ray tube are discussed. Doses obtained by the water phantom and contrast of the iodine agent image are also provided for both cases.
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WEPME034	Soft X-ray Reflectivity and Photoelectron Yield of Technical Materials: Experimental Input for Instability Simulations in High Intensity Accelerators	photon, electron, radiation, synchrotron	2335
	R. Cimino INFN/LNF, Frascati (Roma), Italy R. Cimino CERN, Geneva, Switzerland F. Schäfers HZB, Berlin, Germany
	High luminosity particle accelerators can suffer from serious performance drop or limitations due to interaction of the synchrotron radiation produced by the accelerator itself with the accelerator walls. Such interaction may produce a number of photoelectrons, that can either seed electron cloud related instabilities and/or interact anyway with the beam itself, potentially causing its deterioration. To correctly take these effects into account simulation codes depends on the realistic knowledge of Reflectivity and Photoelectron Yield of technical material. In this work we present relevant experimental data for some of the mostly used technical surfaces in accelerators.
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WEPME048	Preliminary Design of the HiLumi-LHC Triplet Area Beam Screen	shielding, cryogenics, vacuum, luminosity	2378
	R. Kersevan, C. Garion, N. Kos CERN, Geneva, Switzerland
	The so-called beam screen (BS) is a proven solution for intercepting the thermal loads caused by the circulating beams in the cryogenically-cooled sections of the LHC and minimizing dynamic vacuum effects. The new triplet area foreseen for the HiLumi-LHC machine upgrade has the additional feature of needing internal tungsten shields to reduce the amount of collision debris which is deflected by the high-gradient triplet magnets towards the superconducting magnets' cold masses and coils. The very aggressive optics design, based on large beam separations, calls for a maximum of physical space to remain available to the counter rotating beams in the common BS. This places severe constraints to the fabrication and installation tolerances of the BS itself, in addition to affecting the design and routing of the cryogenic lines in the area. The latest version of the BS design will be shown and discussed, together with future plans for testing materials, fabrication procedures, and installation. * The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404
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WEPRI059	Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end	laser, diagnostics, vacuum, gun	2618
	D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, D. Snee Fermilab, Batavia, Illinois, USA
	Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. The Front-End consists of a 1.5 cell normal conducting RF Gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a diagnostic area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.
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THPRO034	Design of the LCLS-II Electron Optics	undulator, linac, quadrupole, electron	2940
	Y. Nosochkov, P. Emma, T.O. Raubenheimer, M. Woodley SLAC, Menlo Park, California, USA
	Funding: Work supported by the US Department of Energy Contract DE-AC02-76SF00515. The LCLS-II project is a high repetition rate, high average brightness free-electron laser based on the existing facilities at the SLAC National Accelerator Laboratory. The LCLS-II will be driven by a new CW superconducting RF (SCRF) 4-GeV linac replacing the existing Cu-linac in the 1st km of the linac tunnel. The SCRF linac will include chicanes for providing full compression of the electron bunch length. After the linac, the electron beam will be directed into the existing 2-km bypass line connecting to the Beam Switch Yard (BSY), where a new spreader system will allow a high rate bunch-by-bunch deflection into the hard X-ray (HXR) or soft X-ray (SXR) transport lines, or towards the BSY high power dump. The HXR line will include a new variable gap undulator replacing the existing LCLS-I undulator and will reuse the existing LCLS-I linac-to-undulator and dump transport lines. The SXR will require a new transport line sharing the same tunnel with the HXR and will include a new variable gap undulator. Overview of the electron beam transport and the optics design are presented.
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THPRO047	Linac Design for the Proposed NSRRC THz/VUV FEL Facility	electron, linac, bunching, emittance	2971
	N.Y. Huang, W.K. Lau, A.P. Lee NSRRC, Hsinchu, Taiwan A. Chao, J. Wu SLAC, Menlo Park, California, USA C.H. Chen NTHU, Hsinchu, Taiwan
	A driver linac based on a photocathode RF gun injector system for a proposed free electron laser facility at National Synchrotron Radiation Research Center (NSRRC) in Taiwan is under study. This facility is designed to be operated in two modes, one for the VUV application and one for the THz application to fulfil the user needs. Generally the VUV radiation prefers a low emittance, high peak current beam free from collective instability during acceleration and magnetic pulse compression, whereas the THz radiation needs a moderate charge in hundred femtosecond bunch length free from space charge degradation in a transport line. In this paper, the schemes of bunch compression as well as the strategy to optimize and control of the beam quality will be presented.
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THPRO066	Correction of the Higher Order Dispersion for Improving Momentum Acceptance	storage-ring, electron, emittance, betatron	3029
	M. Takao, K.K. Kaneki, Y. Shimosaki, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan
	May 2013 we lowered the emittance of the SPring-8 storage ring from 3.5 nm¥cdotrad to 2.4 nm¥cdotrad to enhance the brilliance. At the optics change the momentum acceptance shrunk from 3.2 ¥% to 2.4 ¥%. Then, by carefully correcting the second order dispersion, we recovered the momentum acceptance up to 2.8 ¥%, which results in doubling the Touschek beam lifetime. Although the injection efficiency decreased by more than 10 ¥% by the dispersion correction, we restored it by means of suppressing the amplitude dependent tune shift. Here we describe these improvements of the nonlinear dynamics of the SPring-8 storage ring.
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THPRO075	High-chromaticity Optics for the MAX IV 1.5 GeV Storage Ring	storage-ring, sextupole, lattice, dynamic-aperture	3053
	T. Olsson, S.C. Leemann MAX-lab, Lund, Sweden
	The MAX IV facility currently under construction in Lund, Sweden will include a 1.5 GeV storage ring. To prevent head-tail instability, the negative natural chromaticities of the MAX IV 1.5 GeV storage ring have been corrected to positive values using sextupole gradients in the focusing quadrupoles along with dedicated sextupole magnets. To allow adjustment of the chromaticity correction, weak correction sextupoles have been inserted into the lattice. A high-chromaticity optics has been developed for the MAX IV 1.5 GeV storage ring in case instability issues arise during commissioning. Two chromatic sextupole families were used to correct the linear chromaticity. The tune footprint was then tailored using the remaining two sextupole families with the goal of maximizing dynamic aperture and Touschek lifetime. This paper describes the recently developed high-chromaticity optics for the MAX IV 1.5 GeV storage ring and discusses performance limitations of the optics constrained by available gradient strength in the sextupoles.
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THPRO076	Frequency Maps Analysis of Tracking and Experimental Data for the SLS Storage Ring	synchrotron, resonance, dynamic-aperture, damping	3056
	P. Zisopoulos, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland A. Streun PSI, Villigen PSI, Switzerland V.G. Ziemann Uppsala University, Uppsala, Sweden
	Frequency Maps Analysis (FMA) has been widely used in beam dynamics in order to study dynamical aspects of the particles linear and non-linear motion, such as optics functions distortion, coupling, tune-shift and resonances. In this paper, FMA is employed to explore the dynamics of models of the Swiss Light Source (SLS) storage ring and compare them with measured turn by turn (TxT) position data. In particular, a method is proposed for estimating the momentum spread using synchrotron sidebands of the Fourier spectrum of the TxT data.
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THPRO080	The FiDeL Model at 7 TeV	operation, quadrupole, injection, dipole	3069
	N. Aquilina, M. Giovannozzi, P. Hagen, M. Lamont, A. Langner, E. Todesco, R. Tomás, J. Wenninger CERN, Geneva, Switzerland N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta
	After the long shut down of 2013-2014, the LHC energy will be pushed toward 7 TeV. In this range of energy, the main magnets will enter a new regime. For this reason, this paper will present a detailed study of the performance of the FiDeL model that could be critical for the operation in 2015. In particular this paper will study the saturation component and its precision in the model, together with the hysteresis error. The effect of these two components and their errors on the beta-beating is also given. Furthermore, an estimate of the dynamic effects visible in the tune and chromaticity will be presented for the 7 TeV operation.
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THPRO083	Weak-strong Beam-beam Simulations for HL-LHC	simulation, 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.
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THPRO091	Strength of Horizontal Intrinsic Spin Resonances in the AGS	resonance, polarization, emittance, proton	3098
	Y. Dutheil, L. Ahrens, J.W. Glenn, H. Huang, F. Méot, T. Roser, 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. Crossing of horizontal intrinsic resonances is today the main source of polarization losses in the AGS, in its dual partial snakes configuration for polarized proton acceleration. Polarization losses were greatly reduced by the AGS tune jump system. However total polarization transmission through the AGS cycle is not yet achieved, still partially due to the horizontal intrinsic resonances. This paper will explore the effect of optical distortions and different horizontal tunes on the strength of horizontal intrinsic resonances. Various options will be presented and practicability will be addressed. Theoretical model and multiparticle trackings using the Zgoubi code will show the expected polarization gains of different scenarios.
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THPRO107	Application Programs of Elettra and FERMI@Elettra	controls, booster, software, undulator	3146
	F. Iazzourene, C. Scafuri Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	At Elettra we have high level software application programs used on the ring and others, based on the TANGO control, a new High Level Framework and a beam optics module, firstly developed and successfully used for the commissioning and operation of the Elettra booster and now for FERMI@Elettra transfer lines. The paper describes the present status and some of the application programs.
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THPME032	Beam Transfer Studies for LINCE Experimental Areas	beam-transport, quadrupole, linac, acceleration	3292
	L. Acosta, C. Bonțoiu, I. Martel, A.R. Pinto Gómez, A.C.C. Villari University of Huelva, Huelva, Spain J. Lucas Elytt Energy, Madrid, Spain A.C.C. Villari FRIB, East Lansing, Michigan, USA
	Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA. Beam transport from the exit of the LINCE linac to experimental areas has been optimized for a few ion species using transfer matrix calculations performed in MADX. An alpha spectrometer based on a double-bending achromat lattice has been used as dispersion suppressor and particle tracking studies have been carried out in GPT along it and the three beamlines. Realistic quadrupole and dipole magnet design achieved in Comsol enabled accurate particle tracking studies and evaluation of the beam parameters delivered at the target.
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THPME068	Optics Design of the High-power Proton Synchrotron for LAGUNA-LBNO	injection, dipole, proton, quadrupole	3391
	Y. Papaphilippou, J. Alabau-Gonzalvo, A. Alekou, F. Antoniou, I. Efthymiopoulos, R. Steerenberg CERN, Geneva, Switzerland
	Funding: Work supported by EC/FP7 grant 284518 The prospects for future high-power proton beams for producing neutrinos at CERN within the LAGUNA-LBNO study, include the design of a 2 MW High-Power Pro- ton Synchrotron (HP-PS). In this paper, the optics design of the ring is reviewed, comprising Negative Momentum Compaction (NMC) arc cells and quadrupole triplet long straight sections, flexible enough to achieve the constraints imposed mainly by different beam transfer equipment and processes. A global tunability study is undertaken includ- ing aperture and magnet parameter considerations. Basic correction systems are specified and their impact to beam dynamics including dynamic aperture is finally evaluated.
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THPME069	Performance Studies of the SPS Beam Dump System for HL-LHC Beams	proton, kicker, simulation, operation	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
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THPME080	Reflective Streak Camera Bunch Length Measurements at the Australian Synchrotron	cavity, storage-ring, impedance, synchrotron	3421
	M.J. Boland, Y.E. Tan SLSA, Clayton, Australia T.M. Mitsuhashi KEK, Ibaraki, Japan
	The bunch length of the 3 GeV electron storage ring at the Australian Synchrotron has been measured using reflective input optics feeding a streak camera. An Offner optical design was employed to reduce the chromatic broadening of the input optics of the streak camera. Using the reflective input optics the bunch length is measured to be 15% shorter than with the refractive input optics. The measured bunch length is now in good agreement with the model of the storage ring and the values are being used for calibration, monitoring and optimisation of the machine. The results of studies to characterise the streak camera shall also be presented.
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THPME089	On the Suitability of Longitudinal Profile Measurements using Smith-Purcell Radiation for Short High Current Proton Beams	radiation, proton, simulation, detector	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.
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THPME116	Studies on a Diagnostic Pulse for FLASH	betatron, diagnostics, linac, experiment	3506
	F. Mayet, R.W. Aßmann, S. Schreiber, M. Vogt DESY, Hamburg, Germany
	The long-term stability of the beam optics at FLASH is crucial for all connected experiments and the operation of the new second beamline FLASH2. It is therefore desirable to have a simple procedure to monitor the beam optics routinely and at the same time minimally invasive. This way user operation is not disturbed. An automated procedure, which has been successfully employed at the SLAC linac is presented in the context of FLASH. The betatron oscillations of selectively kicked pulses are recorded using BPMs at a fixed time interval. An online algorithm is then used to extract the betatron phase advance, as well as potential growth of the betatron oscillation amplitude and the Twiss parameters beta and alpha. Using this method, the long-term beam optics stability can be monitored in order to identify potential sources of drifts.
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THPME156	Convergent Cherenkov Radiation from Dielectric Targets	target, radiation, vacuum, FEL	3626
	S.N. Galyamin, E.S. Belonogaya, A.V. Tyukhtin, V.V. Vorobev Saint-Petersburg State University, Saint-Petersburg, Russia E.S. Belonogaya LETI, Saint-Petersburg, Russia
	Funding: Work was supported by the Grant of the President of Russian Federation (No. 273.2013.2). Cherenkov radiation is a convenient tool for charged particle detection and bunch diagnostics. However, due to the complexity of real radiator geometry, different approximate techniques are elaborated for investigation of excited radiation. Here we develop recently reported* approximate method for calculating Cherenkov radiation of a charge flying near a dielectric target having two main boundaries (the first interacts with a charge field and the second mainly refracts a generated radiation). We focus on cases where the radiation outside the target is convergent and use two methods for field investigation: ray optical technique and aperture integration technique. First, we deal with the case of a conical target with a vacuum channel. Under certain conditions, this radiation is concentrated near the line being the symmetry axis of the target. Second, we find the specific shape of the target that concentrates radiation in a small vicinity of given point (focus). Such targets can be used for improvement of detectors and bunch diagnostics systems based on Cherenkov effect. A.P. Potylitsyn et al., Diffraction Radiation from Relativistic Particles, STMP 239 (Springer, 2010). *E.S. Belonogaya, A.V. Tyukhtin, S.N. Galyamin, Phys. Rev. E, 87, 043201 (2013).
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THPME163	Beam Size and Emittance Reconstruction in the RMTL of Future Linear Colliders	emittance, diagnostics, target, coupling	3647
	A. Faus-Golfe, J. Resta-López IFIC, Valencia, Spain
	Funding: Work supported by FPA2010-21456-C02-01 Precise and fast beam size measurement and emittance reconstruction in the different subsystems and transfer lines of the Future Linear Colliders (ILC and CLIC) will be essential for beam tuning in order to achieve the required luminosity. In this paper we investigate the feasibility of using a multi-Optical Transition Radiation (m-OTR) system for fast transverse beam size measurement, emittance reconstruction and coupling correction in the Ring to Main Linac (RTML) of the FLCs. Diagnostic sections of the RTML have been matched to the optimum optical conditions for emittance reconstruction. The necessary requirements for the OTR monitors to be placed in the RTML are discussed.
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THPME168	Proton Beam Imaging Options for the ESS Target	target, proton, radiation, neutron	3659
	C.A. Thomas, T.J. Grandsaert, M. Göhran, R. Linander, T.J. Shea ESS, Lund, Sweden
	Conceptual design of an imaging system for the ESS proton beam current density on target is presented. The window separating the linac HV from the 1bar He-filled target station will be used as a source for imaging by means of either OTR or luminescence. The system presents many challenges to be addressed. The window and the primary optics will be exposed to extremely high radiation doses, providing heat cycles and mechanical stresses near the engineering limits, but also may change the surface properties of the window and the optics. The window lifetime expected to be less than 1 year will have to be replace bi-annually, imposing remote handling design for the window but also for part of the optics. In addition, the imaging system should be able to form an image from low to high current beam operations, in order to retrieve beam profile distribution and power density distribution of both static and raster beam, imposing a large numerical aperture (NA), but also to transport the image at more than 15m distance where radiation level is compatible with camera and pc stable operation and human access during commissioning and neutron production.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME168
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THPME169	Status of the New Beam Size Monitor at SLS	alignment, emittance, laser, radiation	3662
	J. Breunlin, Å. Andersson MAX-lab, Lund, Sweden N. Milas LNLS, Campinas, Brazil M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun PSI, Villigen PSI, Switzerland
	The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required a beam size monitor with the ability to verify a sub-pmrad vertical emittance. This corresponds to a beam height of less than 4 μm. Within the TIARA Work Package ‘SLS Vertical Emittance Tuning’ a new beam size monitor was designed and built. The monitor is based on the imaging of the pi-polarized synchrotron radiation (SR) in the visible and UV spectral ranges. Besides imaging the monitor provides interferometric methods using vertically or horizontally polarized SR. With these complementary methods the consistency of beam size measurements is verified. An intermediate configuration of the monitor beamline using a lens as the focusing element has been commissioned in 2013. With this setup a vertical beam size of 4.8±0.5 μm, corresponding to a vertical emittance of 1.7±0.4 pmrad has been measured. During 2014 the monitor was commissioned in its final configuration with a toroidal mirror. The use of reflective optics allows wider bandwidth imaging and thus higher intensity. We report on challenges during commissioning and present first images of SR taken with the toroidal mirror.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME169
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THPME173	Beam-based Measurements of the CPS Wire Scanner Precision and Accuracy	emittance, synchrotron, simulation, 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.
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THPME184	Improvement of Beam Imaging Systems through Optics Propagation Simulations	simulation, radiation, 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
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THPRI010	FCC-ee Final Focus with Chromaticity Correction	dynamic-aperture, sextupole, collider, lattice	3782
	H. Garcia, R. Tomás, R. Tomás CERN, Geneva, Switzerland
	A 100 km circular electron-positron collider is considered as one of the possible future high energy facilities. In order to achieve a high luminosity, strong beam focusing at the Interaction Point is used requiring the correction of the chromatic aberrations. In this paper we study preliminary designs of a Final Focus System for the TLEP collider with chromatic correction. Beam orbit stability and dynamic aperture calculations are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI010
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Paper

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Other Keywords

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MOPRO035

Update on Nonlinear Collimation Schemes for the LHC

collimation, sextupole, simulation, 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.

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MOPRO037

Collimator Fast Failure Losses for Various HL-LHC Configurations

collimation, simulation, 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.

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MOPRO040

Collimation Cleaning for HL-LHC Optics Scenarios with Error Models

simulation, collimation, alignment, 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.

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MOPRO041

Multi-turn Tracking of Collision Products at the LHC

proton, simulation, luminosity, betatron

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.

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MOPRO042

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

dipole, collimation, simulation, 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.

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MOPRO046

Comparison of MERLIN/SixTrack for LHC Collimation Studies

collimation, scattering, simulation, 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.

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MOPRO053

Study of Upgrade Scenarios for the SOLEIL Storage Ring

emittance, lattice, dipole, sextupole

203

R. Nagaoka, P. Brunelle, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Within the scope of a future major upgrade of the SOLEIL storage ring, presently having the energy of 2.75 GeV, the circumference of 354 m and the horizontal emittance of 3.7 nm.rad, towards a Diffraction Limited Storage Ring (DLSR), the present paper presents and discusses the outcomes of a series of studies launched to explore different possible scenarios for the magnet lattice arrangement, under the constraint of making the upgrade in the same existing machine tunnel. Two scenarios were presented earlier in this context, which both preserved all the existing free straight sections for insertions, though the bending magnet positions were not strictly conserved. The purpose of the extended studies is to explore, in particular, the range of horizontal emittance that can be reached by hypothetically removing some of the existing geometric constraints, such as suppressing or shortening partially the straight sections. The emittance range is equally studied by fulfilling rigorously all constraints. The dependence of the nonlinear properties of the magnet lattice on the linear optics is simultaneously investigated.

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MOPRO058

The Low-alpha Lattice and Bunch Length Limits at BESSY-VSR

radiation, storage-ring, coupling, dipole

216

P. Goslawski, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung and Land Berlin.
An upgrade of the BESSY II ring to a Variable bunch length Storage Ring BESSY^VSR has been recently proposed *, by introducing strongly focusing superconducting cavities. This will allow to store simultaneously long and short bunches. In the regular user optics, bunch lengths of 15 ps (rms) and down to 1.5 ps (rms) are expected. Bunches as short as 300 fs (rms), close to the bunch length limit, and a ring current of 3.5 mA at the bunch bursting threshold can be provided by using a modified low-alpha optics. This presentation will discuss the properties of the low-alpha optics and intrinsic bunch length limits, given by coupling effects of the longitudinal and horizontal plane.
* G. Wüstefeld, A. Jankowiak, J. Knobloch, M.Ries, "Simultaneous Long and Short Electron Bunches in the BESSYII Storage Ring", Proceedings of IPAC2011, San Sebastian, Spain.

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MOPRO068

Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation

simulation, synchrotron, storage-ring, operation

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.

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MOPRO083

Design Study of High Brilliant Optics at the SPring-8 Storage Ring

emittance, photon, brilliance, electron

283

Y. Shimosaki, T. Aoki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, H. Ohkuma, M. Shoji, K. Soutome, S. Takano, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

At the SPring-8 storage ring, design study of beam optics concentrating particularly on increasing brilliance, not flux density, is in progress besides continuous efforts of increasing both brilliance and flux density for the user optics. The natural emittances are theoretically reduced from 2.41 nmrad at 8 GeV to 2.27 nmrad (8 GeV), 1.78 nmrad (7 GeV) and 1.33 nmrad (6 GeV) by utilizing an emittance damping effect by the insertion devices. The designed optics has experimentally been examined at 6 GeV, and the electron beam parameters have been confirmed by measurements at the diagnostics beamlines.
* Y. Shimosaki et al., “New Optics with Emittance Reduction at the SPring-8 Storage Ring”, IPAC13, MOPEA027.

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MOPRO108

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

lattice, linac, experiment, simulation

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.

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MOPME021

Vicky: Computer Code Update

quadrupole, multipole, undulator, sextupole

421

F. Iazzourene
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Vicky is a computer code for designing and simulating charged particle accelerators*. We recall mainly that Vicky is a very user friendly code, the particle motion is described by 10 parameters: four beta-functions, four alpha-functions and two phase advances, and a large variety of insertion devices, wigglers and undulators, linearly and elliptically polarized, are treated. The features include Twiss functions matching, orbit correction, tune and chromaticity adjustment, dynamic aperture and phase space tracking. The paper describes new aspects and the present status.
* F. IAZZOURENE, “Vicky: A Computer Code for Use in the Design and Simulation of Particle Accelerators”, proceedings IPAC 2011.

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MOPME040

MadFLUKA Beam Line 3D Builder. Simulation of Beam Loss Propagation in Accelerators

dipole, lattice, shielding, database

463

M. Santana-Leitner, Y. Nosochkov, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76-SFO0515
Beam tracking programs provide information of orbits along the nominal trajectory to design beam-line optics. Other aspects like machine or radiation protection, which inspect the transverse dimensions and volumes, are simulated with radiation transport Monte Carlo codes, some of which also include magnetic tracking capabilities. Evaluation of certain aspects, like beam loss shower induced propagation along a beam line, or beam mis-steering phase-space, would require to combine features of both types of codes, or use the latter ones with full accelerator 3D implementations, often too cumbersome and time consuming. This paper presents MadFLUKA, a program that produces FLUKA compatible geometries from MAD files. Objects selected from a user user-configurable database are auto-replicated with the rules of ‘twiss’ and ‘survey’ files to create beam lines with hundreds of components. FLUKA magnetic subroutine is generated from MAD optics, including history randomization of fields for ray-trace analysis of mis-steering failures. MadFLUKA is used in the design of the LCLS-II, at SLAC.

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MOPRI077

Hi-Lumi LHC Collimation Studies with MERLIN Code

collimation, scattering, proton, simulation

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.

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MOPRI096

The New Transfer Line Collimation System for the LHC High Luminosity Era

injection, collimation, luminosity, extraction

839

V. Kain, C. Bracco, B. Goddard, F.L. Maciariello, M. Meddahi, A. Mereghetti, G.E. Steele, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

A set of passive absorbers is located at the end of each of the 3 km long injection lines to protect the LHC in case of failures during the extraction process from the LHC’s last pre-injector or the beam transfer itself. In case of an erroneous extraction, the absorbers have to attenuate the beam to a safe level and be robust enough themselves to survive the impact. These requirements are difficult to fulfil with the very bright and intense beams produced by the LHC injectors for the high luminosity era. This paper revisits the requirements for the SPS-to-LHC transfer line collimation system and the adapted strategy to fulfill these for the LHC high luminosity operation. A possible solution for the new transfer line collimation system is presented.

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MOPRI098

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

collimation, luminosity, injection, simulation

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.

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MOPRI099

Feasibility Studies for 100 GeV Beam Transfer Lines for a CERN Neutrino Facility

target, dipole, quadrupole, focusing

849

M. Kowalska, W. Bartmann, C. Bracco, B. Goddard, M. Nessi, R. Steerenberg, F.M. Velotti
CERN, Geneva, Switzerland

For a potential future CERN neutrino facility it is considered to extract a 100 GeV proton beam from the second long straight section in the SPS into the existing TT20 transfer line leading to the North Area. Two transfer line design options were developed simultaneously: early-branching from TT20 using existing, recuperated ‘experimental area’ DC dipoles and alternatively late-branching close to the target area, which requires superconducting magnets. This paper describes the feasibility of the two concepts in addition to the detailed study of the early-branching option. Optics and line geometry optimization are discussed and orbit correction is presented.

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MOPRI102

Upgrades of the CERN PS Booster Ejection Lines

emittance, injection, quadrupole, dipole

858

W. Bartmann, J.L. Abelleira, K. Hanke, M. Kowalska
CERN, Geneva, Switzerland

The PS Booster extraction energy will be augmented from 1.4 to 2 GeV to reduce intensity limits due to space charge at the PS proton injection. For this upgrade the transfer line between PS Booster and PS will be modified for 2 GeV operation and pulse to pulse optics modulation for different beam types. Also the PS Booster measurement line will also be upgraded to 2 GeV and shall provide improved optics solutions for emittance measurements while reducing the loss levels recorded during operation. This paper describes the foreseen optics solutions for both transfer lines.

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MOPRI116

Beam Flattening System based on Non-linear Optics for High Power Spallation Neutron Target at J-PARC

octupole, target, neutron, proton

896

S.I. Meigo, A. Akutsu, K.I. Ikezaki, M. Ooi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
H. Fujimori
KEK/JAEA, Ibaraki-Ken, Japan

In the Japanese Spallation Neutron Source (JSNS) of J-PARC, a mercury is utilized as a target material. Since a serious pitting erosion was found at the target vessel at SNS in ORNL and JSNS, a reduction of a peak current density is required. In order to decrease the peak, we have developed the beam optics based on a non linear using an octupole magnets. In a design calculation, it is found that the peak current density of 30 % can be reduced by introducing the octupole magnets. A status of the design and the experimental results will be reported.

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TUOBA02

Design Study of an ERL Test Facility at CERN

electron, cryomodule, cavity, linac

921

E. Jensen, C. Bracco, O.S. Brüning, R. Calaga, N. Catalán Lasheras, B. Goddard, R. Torres-Sanchez, A. Valloni
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom

The modern concept of an Energy Recovery Linac allows providing large electron currents at large beam energy with low power consumption. This concept is used in FEL’s, electron-ion colliders and electron coolers. CERN has started a Design Study of an ERL Test Facility with the purpose of 1) studying the ERL principle, its specific beam dynamics and operational issues, as relevant for LHeC, 2) providing a test bed for superconducting cavity modules, cryogenics and integration, 3) studying beam induced quenches in superconducting magnets and protection methods, 4) providing test beams for detector R&D and other applications. It will be complementary to existing or planned facilities and is fostering international collaboration. The operating frequency of 802 MHz was chosen for performance and for optimum synergy with SPS and LHC; the design of the cryomodule has started. The ERL Test Facility can be constructed in stages from initially 150 MeV to ultimately 1 GeV in 3 passes, with beam currents of up to 80 mA. Parameters to serve the above-mentioned purposes are well defined and possible lattice designs have well advanced.

Slides TUOBA02 [14.419 MB]

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TUPRO001

Alternative High Luminosity LHC Matching Section Layout

injection, quadrupole, luminosity, cavity

990

B. Dalena, A. Chancé
CEA/IRFU, Gif-sur-Yvette, France
R. De Maria
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.
In the framework of the HL-LHC Upgrade project possible variants for the layout of the LHC matching section located in the high luminosity insertions are investigated. This layout is optimized to reduce the demand on the voltage of the crab cavities, it also improves the optics squeeze-ability, both in ATS[1] and non-ATS mode. Moreover the injection and transitions to collision optics are also discussed. [1] S. Fartoukh, ‘’An Achromatic Telescopic Squeezing (ATS) Scheme for LHC Upgrade’’, in proceedings of IPAC11, p. 2088.

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TUPRO003

Fast Crab Cavity Failures in HL-LHC

operation, simulation, 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.

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TUPRO008

Specification of Field Quality of the Interaction Region Magnets of the High Luminosity LHC Based on Dynamic Aperture

lattice, injection, quadrupole, dipole

1013

Y. Nosochkov, Y. Cai, M.-H. Wang
SLAC, Menlo Park, California, USA
R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh
CERN, Geneva, Switzerland

Funding: Work partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404, and by the US LARP through US Department of Energy.
The high luminosity LHC upgrade (HL-LHC) requires new magnets in the low-beta interaction regions with a larger aperture than in the existing LHC. These include the Nb3Sn superconducting (SC) inner triplet quadrupoles, Nb-Ti SC separation dipoles D1 and D2, and SC matching quadrupoles Q4 and Q5. The large aperture is necessary for accommodating the increased beam size caused by significantly higher beta functions in these magnets in the collision optics. The high beta functions also enhance the effects of field errors in these magnets leading to a smaller dynamic aperture (DA). It is, therefore, critical to determine the field quality specifications for these magnets which 1) satisfy an acceptable DA, and 2) are realistically achievable. The estimates of expected field quality obtained from magnetic field calculations and measurements were used as a starting point. Then, based on the DA study, the field errors were optimized in order to reach an acceptable DA. The DA calculations were performed using SixTrack. Details of the optimization process and summary of the field quality specifications for collision and injection energies are presented.

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TUPRO011

New Tools for K-modulation in the LHC

quadrupole, injection, collider, controls

1024

M. Kuhn, B. Dehning, V. Kain, R. Tomás, G. Trad
CERN, Geneva, Switzerland

For many applications, the precise knowledge of the beta function at a given location is essential. Several measurement techniques for optics functions are used in the LHC to provide the most suitable method for a given scenario. A new tool to run k-modulation measurements and analysis is being developed with the aim to be fully automatic and online. It will take constraints of various systems such as tune measurement precision, powering limits of the LHC superconducting circuits and limits of their quench protection systems into account. It will also provide the possibility to sinusoidally modulate the currents of the investigated quadrupoles with a predefined frequency and amplitude to increase the measurement precision further. This paper will review the advantages and limitations of k-modulation measurements in the LHC with and without sinusoidal current modulation. The used algorithms and tools will be presented and estimates on the obtainable beta function measurement precision will be given.

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TUPRO018

Prospects for the LHC Optics Measurements and Corrections at Higher Energy

coupling, software, GUI, quadrupole

1046

R. Tomás, T. Bach, J.M. Coello de Portugal, V. Kain, M. Kuhn, A. Langner, Y.I. Levinsen, K.S.B. Li, E.H. Maclean, N. Magnin, V. Maier, M. McAteer, T. Persson, P.K. Skowroński, R. Westenberger
CERN, Geneva, Switzerland
E.H. Maclean
JAI, Oxford, United Kingdom
S.M. White
BNL, Upton, Long Island, New York, USA

LHC will resume operation in 2015 at 6.5 TeV. The higher energy allows for smaller IP beta functions, further enhancing the optics errors in the triplet quadrupoles. Moreover the uncertainty in the calibration of some quadrupoles will slightly increase due to saturation effects. The complete magnetic cycle of the LHC will take longer due to the higher energy and extended squeeze sequence. All these issues require more precise and more efficient optics measurements and corrections to guarantee the same optics quality level as in 2012 when a 7% peak beta-beating was achieved. This paper summarizes the on-going efforts for achieving faster and more accurate optics measurements and corrections.

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TUPRO020

Integration of a Neutral Absorber for the LHC Point 8

luminosity, dipole, operation, injection

1052

A. Santamaría García, R. Alemany-Fernández, H. Burkhardt, F. Cerutti, L.S. Esposito, N.V. Shetty
CERN, Geneva, Switzerland

The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of L = 1-2 . 10³³ cm^-2 s⁻¹, with a pileup of 5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.

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TUPRO022

Implementation of Luminosity Leveling by Betatron Function Adjustment at the LHC Interaction Points

luminosity, experiment, operation, betatron

1058

J. Wenninger, A.A. Gorzawski
CERN, Geneva, Switzerland

Growing expectations for integrated luminosity during upcoming LHC runs introduce new challenges for LHC beam operation in the scope of online luminosity control. Because some LHC experiments are limited in the maximum event rates, their luminosity is leveled to a constant value. Various techniques may be used for luminosity leveling, changing the betatron function at the interaction point is one of them. This paper explains the main operational requirements of a betatron function leveling scheme for the upcoming LHC run. Issues concerning the beam optics, orbits and collimator settings are discussed. The proposed architecture for control system integration will be discussed. A few operational scenarios with different beam configurations foreseen for the next LHC run will be presented.

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TUPRO024

Benchmarking Studies of Intra Beam Scattering for HL-LHC

lattice, luminosity, injection, scattering

1064

D. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A. Wolski
The University of Liverpool, Liverpool, United Kingdom
A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404
The effects of Intra Beam Scattering (IBS) in the High Luminosity upgrade of the LHC (HL-LHC) will be stronger compared to effects in the present LHC because of the high intensity of the proton bunches and the new proposed optics. We present benchmarking studies carried out for the present LHC at injection and collision energies as well as HL-LHC at collision energy with the Achromatic Telescopic Squeezing optics. The results of IBS growth-rate calculations using the full Bjorken-Mtingwa formulae* are compared with simplified formulae**, Bane’s high energy approximation***, and the completely integrated modified Piwinski approximation****. The results of calculations based on these methods carried out in Mathematica are compared with results from the codes MAD-X and ZAP.
* J. Broken and S. Mtingwa, Part. Accel. 13, 115 (1983)
** K. Kubo et al, PRST-AB, 8, 081001 (2005)
*** K. Bane, EPAC2002
**** S. Mtingwa and A. Tollestrup, Fermilab-Pub-89/224, 1987.

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TUPRO041

Status of Ion-optical Design of the Collector Ring

antiproton, quadrupole, injection, kicker

1114

O.E. Gorda, A. Dolinskyy, S.A. Litvinov
GSI, Darmstadt, Germany
D.E. Berkaev, I. Koop, P.Yu. Shatunov, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia

The Collector Ring at FAIR will be used for fast cooling of hot antiproton or ion beams. The ring layout as well as the injection and extraction scheme have been modified during the latest design stage. In this paper, we report on the present status of the ion-optical properties of the machine.

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TUPRO042

Ion Optics of the HESR Storage Ring at FAIR for Operation with Heavy Ions

ion, heavy-ion, target, experiment

1117

O.A. Kovalenko, A. Dolinskyy, T. Katayama, Yu.A. Litvinov, T. Stöhlker
GSI, Darmstadt, Germany
B. Lorentz, R. Maier, D. Prasuhn, H. Stockhorst
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) of the FAIR project is primarily designed for internal target experiments with stored and cooled antiprotons, which is the main objective of the PANDA collaboration. However, the HESR storage ring also appears to have remarkable properties to carry out physics experiments with heavy ions. In this paper a new ion optical design allowing the heavy ion operation mode of the HESR is presented. The main goal was to provide an optics which meets the requirements of the future experiments with heavy ion beams. Closed orbit correction, dynamic aperture as well as other characteristics of beam dynamics of the ion optical setup are under analysis in this study.

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TUPRO049

Layout and Optics of the Dump Line at the European XFEL

extraction, kicker, quadrupole, septum

1138

N. Golubeva, V. Balandin, W. Decking
DESY, Hamburg, Germany

The purpose of the optical system, which we call the dump line, is not simply the transport of the beam to the beam dump. It is an essential part of the beam switchyard which provides the possibility to distribute electron bunches of one beam pulse to different FEL beam lines, allowing a flexible selection of the bunch pattern at each FEL experiment. In this paper we describe the final layout of this optical system as it is now under construction.

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TUPRO050

Measurements of the Optical Functions at FLASH

quadrupole, linac, controls, coupling

1141

J. Zemella, T. Hellert, M. Scholz, M. Vogt
DESY, Hamburg, Germany

In 2013 the superconducting soft x-ray Free Electron Laser FLASH at DESY (Hamburg, Germany) the extraction section needed to connect the 2nd beam line FLASH2 was installed. In order to allow simultaneous operation of the two beam lines (FLASH1/2), the optical functions in the extraction area needed to be modified. During the recommissioning of FLASH we have optimized, measured and corrected the optical functions in the machine. We report on the the results and the methods.

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TUPRO056

Merit Functions for the Linac Optics Design for Colliders and Light Sources

emittance, focusing, linac, quadrupole

1159

S. Di Mitri, M. Cornacchia
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
H.-S. Kang
PAL, Pohang, Kyungbuk, Republic of Korea

Optics matching and transverse emittance preservation are key goals for a successful operation of modern high brightness electron linacs. The capability of controlling them in a real machine critically relies on a properly designed magnetic lattice. Conscious of this fact, we introduce an ensemble of optical functions* that permit to solve the often neglected conflict between strong focusing, typically implemented to counteract coherent synchrotron radiation and transverse wakefield instability, and distortion of the transverse phase space induced by chromatic aberrations and focusing errors. A numerical evaluation of the merit functions is applied to existing and planned linac-based free electron lasers.
*S. Di Mitri and M. Cornacchia, Nucl. Instr. Meth. Phys. Research A 735, 60–65 (2014).

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TUPRO058

Lattice Correction Modeling for Fermilab IOTA Ring

lattice, closed-orbit, dipole, insertion

1165

A.L. Romanov
BINP SB RAS, Novosibirsk, Russia
G.T. Kafka, S. Nagaitsev, A. Valishev
Fermilab, Batavia, Illinois, USA

The construction of the Integrable Optics Test Accelerator (IOTA) is underway at Fermilab. Among the main goals of the facility are the proof-of-principle experiments on nonlinear integrable optics and optical stochastic cooling. Both require outstanding quality of the linear lattice and closed orbit. Software was developed to thoroughly test the proposed lattice configurations for error correction performance. The presented analysis is based on a statistical approach on a number of error seeds, such as various alignment, calibration and field errors.

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TUPRO060

First Turn-by-turn Measurements for Beam Dynamics Studies at ALBA

kicker, injection, electron, sextupole

1171

Z. Martí, G. Benedetti, M. Carlà, A. Olmos
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

This paper summarizes the tasks carried out to develop a turn-by-turn (TBT) measurement system at ALBA. These tasks mainly include testing the MAF firmware for the libera BPMs and implementing the necessary analytical tools to infer the beam dynamics parameters. TBT measurements using an injection kicker are presented. Linear and non-linear beam dynamics results are compared with LOCO. Results are still preliminary since a good agreement with the linear model has not been achieved yet.

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TUPRO062

Improvements in the Optics Measurement Resolution for the LHC

simulation, 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.

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TUPRO063

Upgrade of Slicing and Tracking in MAD-X

quadrupole, dipole, lattice, sextupole

1180

H. Burkhardt, L. Deniau, A. Latina
CERN, Geneva, Switzerland

We describe the extension of the functionality of the slicing module and its applications in MAD-X. We can now select thick or thin slicing for individual quadrupoles or groups of quadrupoles and implemented tracking of thick quadrupoles and dipoles in MAD-X. Complex dipole magnets with fringe fields can now automatically be translated to simple bends with extra dipedges.

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TUPRO067

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

target, proton, simulation, 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.

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TUPRO068

Commisioning of the 2.4T Multipole Wiggler and the 6.5T Superconducting Wavelength Shifter at the SIAM Photon Source

emittance, betatron, storage-ring, operation

1192

P. Sudmuang, S. Klinkhieo, P. Klysubun, S. Kongtawong, S. Krainara, N. Suradet, A. Tong-on
SLRI, Nakhon Ratchasima, Thailand

A 2.4 T hybrid multipole wiggler (MPW) and a 6.5 T superconducting wavelength shifter (SWLS) have been successfully installed and commissioned at Siam Photon Source (SPS). The influence of the two insertion devices on the electron beam dynamic at different operating points have been studied in order to determine the optimal lattice configuration for operation. In this paper, the compensation of the linear optics will be presented, and the commissioning scheme will also be described. In addition, the investigation of the difference between the model and the actual observed machine parameters will be reported in details.

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TUPME026

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

impedance, simulation, 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.

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TUPME045

Development of a High-Energy Short-pulse 5-μm Parametric Source for Dielectric Laser Acceleration

laser, acceleration, detector, operation

1460

G. Xu, I. Jovanovic, S.F. Wandel
Penn State University, University Park, Pennsylvania, USA

A compact, high-peak-power 5-μm laser source with pulse duration of sub-100 fs has been designed and being constructed for pumping a dielectric photonic structure to produce an acceleration gradient of order GV/m in dielectric laser acceleration. Breakdown of dielectric structure induced by multiphoton ionization can be mitigated by adopting long wavelength driver laser. Since the dielectric structure scales with the laser wavelength, fabrication tolerances for dielectric structure are relaxed as well. The 5-μm laser source is based on two cascaded optical parametric amplifiers (OPA): a 2-μm BBO OPA with a mixed phase matching scheme is used as a pump source, and a type-I phase-matched ZGP OPA is designed to produce sub-mJ, <100 fs 5-μm laser pulses. The two-stage 2-μm OPA is pumped by a Ti:sapphire amplifier and produces pulse energy of ~2.2 mJ with a pulse duration of 42 fs (~6 optical cycles), and excellent pulse stability and beam quality. Preliminary result of ~50 μJ pulse energy at 5-μm is demonstrated by using single-stage ZGP OPA, and an improved two-stage OPA scheme for production of higher pulse energy at 5-μm is under development.

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TUPRI005

nuSTORM Horn Optimization Study

target, simulation, 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.

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TUPRI026

MAX IV Emittance Reduction and Brightness Improvement

emittance, storage-ring, brightness, lattice

1615

S.C. Leemann, M. Eriksson
MAX-lab, Lund, Sweden

With MAX IV construction well underway and storage ring commissioning expected to commence in July 2015, first studies have been launched to improve the optics of the MAX IV 3 GeV storage ring with the goal of further reducing the emittance from the baseline design (328 pm rad) towards 150 pm rad while improving the matching of the electron beam to insertion devices to further improve the resulting photon brightness. We report on progress in the development of this new optics taking into account the strong impact from intrabeam scattering and insertion devices on the resulting equilibrium emittance. We present initial results and sketch a path towards a first MAX IV upgrade.

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TUPRI081

Feed-forward and Feedback Schemes applied to the Diamond Light Source Storage Ring

feedback, photon, storage-ring, undulator

1757

M.T. Heron, M.G. Abbott, M.J. Furseman, D.G. Hickin, E.C. Longhi, I.P.S. Martin, G. Rehm, W.A.H. Rogers, A.J. Rose, B. Singh
DLS, Oxfordshire, United Kingdom

Since initial operation for users in Jan 2007, Diamond Light Source has developed to support a suite of 22 experimental stations. These stations have resulted in the installation of 24 undulators and two superconducting wigglers in the storage ring. To preserve optics, tune and coupling with the operation of these devices has necessitated the implementation of a number of feed-forward and feedback schemes. The implementation and operation of these correction schemes will be described.

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TUPRI082

Active Optics Stabilisation Measures at the Diamond Storage Ring

injection, quadrupole, feedback, storage-ring

1760

I.P.S. Martin, R. Bartolini, R.T. Fielder, M.J. Furseman, E.C. Longhi, G. Rehm, W.A.H. Rogers, A.J. Rose, B. Singh
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

The Diamond storage ring is currently operated with 26 insertion devices (IDs), including 14 in-vacuum IDs, 7 APPLE-II type helical undulators and 2 superconducting wigglers. Differences in the design, construction and operation of these devices, combined with different Twiss parameters at the source point, mean each has a different impact on tune stability and beta-beat. In turn, these parameters affect the on and off-momentum dynamic aperture and ultimately impact on the injection efficiency and lifetime. Another source of optics variation arises from the coherent tune shift with current, which when injecting from zero current causes the tune to span the available good-tune region. In this paper we discuss the difficulties of operating the Diamond storage ring in top-up mode with these effects, and present the various measures taken to stabilise the storage ring optics.

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TUPRI083

A Fast Optics Correction for the Diamond Storage Ring

quadrupole, storage-ring, emittance, feedback

1763

I.P.S. Martin, M.G. Abbott, R. Bartolini, M.J. Furseman, G. Rehm
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Since March 2013, the Diamond storage ring has been operated with a target vertical emittance of 8 pm.rad. This condition is achieved by first applying a LOCO* optics correction with IDs set to their typical gaps, then offsetting the skew quadrupole magnets in order to increase the vertical emittance again to the desired value. Whilst a feedback application** is able to stabilise the vertical emittance during ID gap and phase changes in the short to medium term, regular applications of LOCO are still required to maintain good coupling control in the longer term. In this paper we describe measures taken to speed up the optics correction procedure, including a fast orbit response matrix measurement, a reduction of the number of magnets used to measure the data, and a distribution of the LOCO calculations to run in parallel.
* J. Safranek, Nucl. Inst. Meth. A, 338, (1997)
** I.P.S. Martin, et al., IPAC 2013, MOPEA071, www. JACoW.org

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TUPRI086

Feedback System Design Techniques for Control of Intra-bunch Instabilities at the SPS

feedback, electron, controls, damping

1769

C.H. Rivetta, J.M. Cesaratto, J.E. Dusatko, J.D. Fox, O. Turgut
SLAC, Menlo Park, California, USA
W. Höfle, G. Kotzian, K.S.B. Li
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).
The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. This paper presents model-based design techniques for feedback systems to address the stabilization of the transverse bunch dynamics. These techniques include in the design the effect of noise and signals perturbing the bunch motion. Different controllers are compared based on stability margins and equivalent noise gain between input-output of the processing channel. The controller design uses as example the bunch dynamics defined by the SPS ring including the Q20 optics.

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WEOBA03

Status of Preparations for a 10 μs Laser-Assisted H⁻ Beam Stripping Experiment

laser, experiment, ion, injection

1864

S.M. Cousineau, A.V. Aleksandrov, V.V. Danilov, T.V. Gorlov, Y. Liu, A.A. Menshov, M.A. Plum, A.P. Shishlo, Y. Wang
ORNL, Oak Ridge, Tennessee, USA
F.G. Garcia, N.F. Luttrell
UTK, Knoxville, Tennessee, USA
D.E. Johnson
Fermilab, Batavia, Illinois, USA
A. Rakhman
ORNL RAD, Oak Ridge, Tennessee, USA
Y. Takeda
KEK, Ibaraki, Japan

Funding: This work is funded by the U.S. DOE under grant number DE-FG02-13ER41967, and by the U.S. DOE under contract number DE-AC05-00OR22725 with UT-Battelle Corporation.
The concept of laser-assisted H⁻ stripping, originated over three decades ago, was successfully demonstrated for a 6 ns, 900 MeV H⁻ beam in 2006. Plans are underway to build on this foundation by performing laser-assisted H⁻ stripping of a 10 μs, 1 GeV H⁻ beam at the Spallation Neutron Source facility; this constitutes a three orders of magnitude improvement over the initial proof of principle demonstration. The central theme of the experiment is the reduction of the required laser power through ion beam manipulations and laser-ion beam temporal matching. This paper discusses the configuration of the experiment, the current and anticipated challenges, and the schedule.

Slides WEOBA03 [2.549 MB]

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WEZA01

Towards an International Linear Collider: Experiments at ATF2

emittance, sextupole, quadrupole, feedback

1867

K. Kubo
KEK, Ibaraki, Japan

For linear colliders, realizing extremely small and stable beam is essentially important. At ILC (International Linear Collider), designed vertical beam size and required position stability at the interaction point is nanometer level. In ATF (Accelerator Test Facility) at KEK, study of the final focus system has been performed using small emittance beams extracted from the damping ring. The project is called ATF2. The ATF2 beam line is designed as a prototype of the final focus system of ILC, with basically the same optics, similar beam energy spread, natural chromaticity and tolerances of magnetic field errors. Its design, construction and operation have been performed as an international collaboration. We have demonstrated the local chromatic correction method, which will be used in ILC, and observed the vertical beam size about 55 nm. Test and demonstration of intra-pulse orbit feedback has been successfully performed in the middle of the ATF2 beam line. For demonstration of nm level stable beam, high resolution beam position monitors were installed around the focal point. Here, we report our achievement, status and future plans.

Slides WEZA01 [1.453 MB]

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WEYB01

Large Dynamic Range Beam Diagnostics for High Average Current Electron LINACs

linac, diagnostics, FEL, brightness

1900

P.E. Evtushenko
JLab, Newport News, Virginia, USA

A number of applications is envisioned now for CW electron LINACs with high average current. A few examples are: driver-accelerators for the next generation of high average brightness SR sources, energy recovery LINACs to be used for frontier research in particle physics - search for dark matter candidate particles, industrial and defense applications. An average beam power of MWs is considered for such applications. Such machines will be required to operate simultaneously with high beam power and peak brightness comparable to the brightest electron beams generated in pulsed LINACs. Combining the high current advantages of storage rings and high peak brightness of LINACs will require such understanding and control of the beam dynamics that 10^-6 fraction of the beam current is taken in to account and controlled during the beam tuning. To make this possible a number of large dynamic range (LDR) (~10⁺⁶) beam diagnostics is under development and test at JLab FEL. Transverse and longitudinal LDR beam profile measurements can be used for LDR measurements of the phase space distribution and its evolution through the accelerator.

Slides WEYB01 [4.581 MB]

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WEPRO006

Beam-driven Terahertz Source based on Open Ended Waveguide with a Dielectric Layer

radiation, vacuum, wakefield, experiment

1949

A.V. Tyukhtin, S.N. Galyamin, V.V. Vorobev
Saint-Petersburg State University, Saint-Petersburg, Russia
S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia

Funding: Work is supported by the Grant of the President of Russian Federation (MK-273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258).
Electromagnetic waves with frequencies from 0.1 THz to 10 THz (usually called the Terahertz gap) are of great importance for a number of scientific and practical applications. Different techniques are known allowing generating these frequencies. However, a current trend of physics and industry is to fill this gap with more powerful and efficient sources. For example, recent experiments have shown promising THz generation in dielectric loaded structures*. Developing this area, we consider the THz emitting scheme where an ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation. The end of the waveguide is supposed to be either orthogonal to the structure axis or skewed. To obtain THz frequencies from waveguides with centimeter or millimeter radii, we consider high order modes. We present typical field patterns (in the Fraunhofer zone) and show that the aperture of the vacuum channel gives, as a rule, the main contribution. We also give simple expressions for the angle of the main pattern lobe.
* S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012).

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WEPRO073

The ESS High Energy Beam Transport after the 2013 Design Update

target, dipole, linac, quadrupole

2121

H.D. Thomsen, S.P. Møller
ISA, Aarhus, Denmark

Following an optimization of the European Spallation Source (ESS) linac, a number of changes have been introduced in the High Energy Beam Transport (HEBT). In particular, about 120 m of beam transport has been allocated to enable an extension of the superconducting linac, thus providing some contingency against poor linac performance and potentially allowing a future beam power upgrade. The changes in layout and beam optics in all HEBT lines will be discussed.

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WEPRO074

Performance of the ESS High Energy Beam Transport under Non-nominal Conditions

target, quadrupole, dipole, simulation

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.

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WEPRO096

X-ray Radiation Source for Low Dose Angiography based on Channeling Radiation

radiation, electron, photon, cavity

2186

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia

Angiography is one of the most reliable and contemporary procedure of the vascular system imaging. X-ray spectrums provided by all modern medical angiographs are too broad to acquire high contrast images and provide low radiation dose at the same time. The new method of narrow X-ray spectrum achieving is based on the idea of channelling radiation application. The X-ray filters used in this method allows eliminating the high energy part of the spectrum and providing dramatic dose reduction. The scheme of the facility including the X-ray filter is discussed. The results of the spectrum analysis for the channelling radiation source and typical angiography X-ray tube are discussed. Doses obtained by the water phantom and contrast of the iodine agent image are also provided for both cases.

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WEPME034

Soft X-ray Reflectivity and Photoelectron Yield of Technical Materials: Experimental Input for Instability Simulations in High Intensity Accelerators

photon, electron, radiation, synchrotron

2335

R. Cimino
INFN/LNF, Frascati (Roma), Italy
R. Cimino
CERN, Geneva, Switzerland
F. Schäfers
HZB, Berlin, Germany

High luminosity particle accelerators can suffer from serious performance drop or limitations due to interaction of the synchrotron radiation produced by the accelerator itself with the accelerator walls. Such interaction may produce a number of photoelectrons, that can either seed electron cloud related instabilities and/or interact anyway with the beam itself, potentially causing its deterioration. To correctly take these effects into account simulation codes depends on the realistic knowledge of Reflectivity and Photoelectron Yield of technical material. In this work we present relevant experimental data for some of the mostly used technical surfaces in accelerators.

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WEPME048

Preliminary Design of the HiLumi-LHC Triplet Area Beam Screen

shielding, cryogenics, vacuum, luminosity

2378

R. Kersevan, C. Garion, N. Kos
CERN, Geneva, Switzerland

The so-called beam screen (BS) is a proven solution for intercepting the thermal loads caused by the circulating beams in the cryogenically-cooled sections of the LHC and minimizing dynamic vacuum effects. The new triplet area foreseen for the HiLumi-LHC machine upgrade has the additional feature of needing internal tungsten shields to reduce the amount of collision debris which is deflected by the high-gradient triplet magnets towards the superconducting magnets' cold masses and coils. The very aggressive optics design, based on large beam separations, calls for a maximum of physical space to remain available to the counter rotating beams in the common BS. This places severe constraints to the fabrication and installation tolerances of the BS itself, in addition to affecting the design and routing of the cryogenic lines in the area. The latest version of the BS design will be shown and discussed, together with future plans for testing materials, fabrication procedures, and installation.
* The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404

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WEPRI059

Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end

laser, diagnostics, vacuum, gun

2618

D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, D. Snee
Fermilab, Batavia, Illinois, USA

Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. The Front-End consists of a 1.5 cell normal conducting RF Gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a diagnostic area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System.

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THPRO034

Design of the LCLS-II Electron Optics

undulator, linac, quadrupole, electron

2940

Y. Nosochkov, P. Emma, T.O. Raubenheimer, M. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by the US Department of Energy Contract DE-AC02-76SF00515.
The LCLS-II project is a high repetition rate, high average brightness free-electron laser based on the existing facilities at the SLAC National Accelerator Laboratory. The LCLS-II will be driven by a new CW superconducting RF (SCRF) 4-GeV linac replacing the existing Cu-linac in the 1st km of the linac tunnel. The SCRF linac will include chicanes for providing full compression of the electron bunch length. After the linac, the electron beam will be directed into the existing 2-km bypass line connecting to the Beam Switch Yard (BSY), where a new spreader system will allow a high rate bunch-by-bunch deflection into the hard X-ray (HXR) or soft X-ray (SXR) transport lines, or towards the BSY high power dump. The HXR line will include a new variable gap undulator replacing the existing LCLS-I undulator and will reuse the existing LCLS-I linac-to-undulator and dump transport lines. The SXR will require a new transport line sharing the same tunnel with the HXR and will include a new variable gap undulator. Overview of the electron beam transport and the optics design are presented.

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THPRO047

Linac Design for the Proposed NSRRC THz/VUV FEL Facility

electron, linac, bunching, emittance

2971

N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
A. Chao, J. Wu
SLAC, Menlo Park, California, USA
C.H. Chen
NTHU, Hsinchu, Taiwan

A driver linac based on a photocathode RF gun injector system for a proposed free electron laser facility at National Synchrotron Radiation Research Center (NSRRC) in Taiwan is under study. This facility is designed to be operated in two modes, one for the VUV application and one for the THz application to fulfil the user needs. Generally the VUV radiation prefers a low emittance, high peak current beam free from collective instability during acceleration and magnetic pulse compression, whereas the THz radiation needs a moderate charge in hundred femtosecond bunch length free from space charge degradation in a transport line. In this paper, the schemes of bunch compression as well as the strategy to optimize and control of the beam quality will be presented.

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THPRO066

Correction of the Higher Order Dispersion for Improving Momentum Acceptance

storage-ring, electron, emittance, betatron

3029

M. Takao, K.K. Kaneki, Y. Shimosaki, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan

May 2013 we lowered the emittance of the SPring-8 storage ring from 3.5 nm¥cdotrad to 2.4 nm¥cdotrad to enhance the brilliance. At the optics change the momentum acceptance shrunk from 3.2 ¥% to 2.4 ¥%. Then, by carefully correcting the second order dispersion, we recovered the momentum acceptance up to 2.8 ¥%, which results in doubling the Touschek beam lifetime. Although the injection efficiency decreased by more than 10 ¥% by the dispersion correction, we restored it by means of suppressing the amplitude dependent tune shift. Here we describe these improvements of the nonlinear dynamics of the SPring-8 storage ring.

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THPRO075

High-chromaticity Optics for the MAX IV 1.5 GeV Storage Ring

storage-ring, sextupole, lattice, dynamic-aperture

3053

T. Olsson, S.C. Leemann
MAX-lab, Lund, Sweden

The MAX IV facility currently under construction in Lund, Sweden will include a 1.5 GeV storage ring. To prevent head-tail instability, the negative natural chromaticities of the MAX IV 1.5 GeV storage ring have been corrected to positive values using sextupole gradients in the focusing quadrupoles along with dedicated sextupole magnets. To allow adjustment of the chromaticity correction, weak correction sextupoles have been inserted into the lattice. A high-chromaticity optics has been developed for the MAX IV 1.5 GeV storage ring in case instability issues arise during commissioning. Two chromatic sextupole families were used to correct the linear chromaticity. The tune footprint was then tailored using the remaining two sextupole families with the goal of maximizing dynamic aperture and Touschek lifetime. This paper describes the recently developed high-chromaticity optics for the MAX IV 1.5 GeV storage ring and discusses performance limitations of the optics constrained by available gradient strength in the sextupoles.

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THPRO076

Frequency Maps Analysis of Tracking and Experimental Data for the SLS Storage Ring

synchrotron, resonance, dynamic-aperture, damping

3056

P. Zisopoulos, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
A. Streun
PSI, Villigen PSI, Switzerland
V.G. Ziemann
Uppsala University, Uppsala, Sweden

Frequency Maps Analysis (FMA) has been widely used in beam dynamics in order to study dynamical aspects of the particles linear and non-linear motion, such as optics functions distortion, coupling, tune-shift and resonances. In this paper, FMA is employed to explore the dynamics of models of the Swiss Light Source (SLS) storage ring and compare them with measured turn by turn (TxT) position data. In particular, a method is proposed for estimating the momentum spread using synchrotron sidebands of the Fourier spectrum of the TxT data.

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THPRO080

The FiDeL Model at 7 TeV

operation, quadrupole, injection, dipole

3069

N. Aquilina, M. Giovannozzi, P. Hagen, M. Lamont, A. Langner, E. Todesco, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

After the long shut down of 2013-2014, the LHC energy will be pushed toward 7 TeV. In this range of energy, the main magnets will enter a new regime. For this reason, this paper will present a detailed study of the performance of the FiDeL model that could be critical for the operation in 2015. In particular this paper will study the saturation component and its precision in the model, together with the hysteresis error. The effect of these two components and their errors on the beta-beating is also given. Furthermore, an estimate of the dynamic effects visible in the tune and chromaticity will be presented for the 7 TeV operation.

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THPRO083

Weak-strong Beam-beam Simulations for HL-LHC

simulation, 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.

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THPRO091

Strength of Horizontal Intrinsic Spin Resonances in the AGS

resonance, polarization, emittance, proton

3098

Y. Dutheil, L. Ahrens, J.W. Glenn, H. Huang, F. Méot, T. Roser, 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.
Crossing of horizontal intrinsic resonances is today the main source of polarization losses in the AGS, in its dual partial snakes configuration for polarized proton acceleration. Polarization losses were greatly reduced by the AGS tune jump system. However total polarization transmission through the AGS cycle is not yet achieved, still partially due to the horizontal intrinsic resonances. This paper will explore the effect of optical distortions and different horizontal tunes on the strength of horizontal intrinsic resonances. Various options will be presented and practicability will be addressed. Theoretical model and multiparticle trackings using the Zgoubi code will show the expected polarization gains of different scenarios.

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THPRO107

Application Programs of Elettra and FERMI@Elettra

controls, booster, software, undulator

3146

F. Iazzourene, C. Scafuri
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

At Elettra we have high level software application programs used on the ring and others, based on the TANGO control, a new High Level Framework and a beam optics module, firstly developed and successfully used for the commissioning and operation of the Elettra booster and now for FERMI@Elettra transfer lines. The paper describes the present status and some of the application programs.

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THPME032

Beam Transfer Studies for LINCE Experimental Areas

beam-transport, quadrupole, linac, acceleration

3292

L. Acosta, C. Bonțoiu, I. Martel, A.R. Pinto Gómez, A.C.C. Villari
University of Huelva, Huelva, Spain
J. Lucas
Elytt Energy, Madrid, Spain
A.C.C. Villari
FRIB, East Lansing, Michigan, USA

Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA.
Beam transport from the exit of the LINCE linac to experimental areas has been optimized for a few ion species using transfer matrix calculations performed in MADX. An alpha spectrometer based on a double-bending achromat lattice has been used as dispersion suppressor and particle tracking studies have been carried out in GPT along it and the three beamlines. Realistic quadrupole and dipole magnet design achieved in Comsol enabled accurate particle tracking studies and evaluation of the beam parameters delivered at the target.

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THPME068

Optics Design of the High-power Proton Synchrotron for LAGUNA-LBNO

injection, dipole, proton, quadrupole

3391

Y. Papaphilippou, J. Alabau-Gonzalvo, A. Alekou, F. Antoniou, I. Efthymiopoulos, R. Steerenberg
CERN, Geneva, Switzerland

Funding: Work supported by EC/FP7 grant 284518
The prospects for future high-power proton beams for producing neutrinos at CERN within the LAGUNA-LBNO study, include the design of a 2 MW High-Power Pro- ton Synchrotron (HP-PS). In this paper, the optics design of the ring is reviewed, comprising Negative Momentum Compaction (NMC) arc cells and quadrupole triplet long straight sections, flexible enough to achieve the constraints imposed mainly by different beam transfer equipment and processes. A global tunability study is undertaken includ- ing aperture and magnet parameter considerations. Basic correction systems are specified and their impact to beam dynamics including dynamic aperture is finally evaluated.

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THPME069

Performance Studies of the SPS Beam Dump System for HL-LHC Beams

proton, kicker, simulation, operation

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

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME069

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THPME080

Reflective Streak Camera Bunch Length Measurements at the Australian Synchrotron

cavity, storage-ring, impedance, synchrotron

3421

M.J. Boland, Y.E. Tan
SLSA, Clayton, Australia
T.M. Mitsuhashi
KEK, Ibaraki, Japan

The bunch length of the 3 GeV electron storage ring at the Australian Synchrotron has been measured using reflective input optics feeding a streak camera. An Offner optical design was employed to reduce the chromatic broadening of the input optics of the streak camera. Using the reflective input optics the bunch length is measured to be 15% shorter than with the refractive input optics. The measured bunch length is now in good agreement with the model of the storage ring and the values are being used for calibration, monitoring and optimisation of the machine. The results of studies to characterise the streak camera shall also be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME080

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THPME089

On the Suitability of Longitudinal Profile Measurements using Smith-Purcell Radiation for Short High Current Proton Beams

radiation, proton, simulation, detector

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.

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THPME116

Studies on a Diagnostic Pulse for FLASH

betatron, diagnostics, linac, experiment

3506

F. Mayet, R.W. Aßmann, S. Schreiber, M. Vogt
DESY, Hamburg, Germany

The long-term stability of the beam optics at FLASH is crucial for all connected experiments and the operation of the new second beamline FLASH2. It is therefore desirable to have a simple procedure to monitor the beam optics routinely and at the same time minimally invasive. This way user operation is not disturbed. An automated procedure, which has been successfully employed at the SLAC linac is presented in the context of FLASH. The betatron oscillations of selectively kicked pulses are recorded using BPMs at a fixed time interval. An online algorithm is then used to extract the betatron phase advance, as well as potential growth of the betatron oscillation amplitude and the Twiss parameters beta and alpha. Using this method, the long-term beam optics stability can be monitored in order to identify potential sources of drifts.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME116

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THPME156

Convergent Cherenkov Radiation from Dielectric Targets

target, radiation, vacuum, FEL

3626

S.N. Galyamin, E.S. Belonogaya, A.V. Tyukhtin, V.V. Vorobev
Saint-Petersburg State University, Saint-Petersburg, Russia
E.S. Belonogaya
LETI, Saint-Petersburg, Russia

Funding: Work was supported by the Grant of the President of Russian Federation (No. 273.2013.2).
Cherenkov radiation is a convenient tool for charged particle detection and bunch diagnostics. However, due to the complexity of real radiator geometry, different approximate techniques are elaborated for investigation of excited radiation*. Here we develop recently reported** approximate method for calculating Cherenkov radiation of a charge flying near a dielectric target having two main boundaries (the first interacts with a charge field and the second mainly refracts a generated radiation). We focus on cases where the radiation outside the target is convergent and use two methods for field investigation: ray optical technique and aperture integration technique. First, we deal with the case of a conical target with a vacuum channel. Under certain conditions, this radiation is concentrated near the line being the symmetry axis of the target. Second, we find the specific shape of the target that concentrates radiation in a small vicinity of given point (focus). Such targets can be used for improvement of detectors and bunch diagnostics systems based on Cherenkov effect.
*A.P. Potylitsyn et al., Diffraction Radiation from Relativistic Particles, STMP 239 (Springer, 2010).
**E.S. Belonogaya, A.V. Tyukhtin, S.N. Galyamin, Phys. Rev. E, 87, 043201 (2013).

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THPME163

Beam Size and Emittance Reconstruction in the RMTL of Future Linear Colliders

emittance, diagnostics, target, coupling

3647

A. Faus-Golfe, J. Resta-López
IFIC, Valencia, Spain

Funding: Work supported by FPA2010-21456-C02-01
Precise and fast beam size measurement and emittance reconstruction in the different subsystems and transfer lines of the Future Linear Colliders (ILC and CLIC) will be essential for beam tuning in order to achieve the required luminosity. In this paper we investigate the feasibility of using a multi-Optical Transition Radiation (m-OTR) system for fast transverse beam size measurement, emittance reconstruction and coupling correction in the Ring to Main Linac (RTML) of the FLCs. Diagnostic sections of the RTML have been matched to the optimum optical conditions for emittance reconstruction. The necessary requirements for the OTR monitors to be placed in the RTML are discussed.

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THPME168

Proton Beam Imaging Options for the ESS Target

target, proton, radiation, neutron

3659

C.A. Thomas, T.J. Grandsaert, M. Göhran, R. Linander, T.J. Shea
ESS, Lund, Sweden

Conceptual design of an imaging system for the ESS proton beam current density on target is presented. The window separating the linac HV from the 1bar He-filled target station will be used as a source for imaging by means of either OTR or luminescence. The system presents many challenges to be addressed. The window and the primary optics will be exposed to extremely high radiation doses, providing heat cycles and mechanical stresses near the engineering limits, but also may change the surface properties of the window and the optics. The window lifetime expected to be less than 1 year will have to be replace bi-annually, imposing remote handling design for the window but also for part of the optics. In addition, the imaging system should be able to form an image from low to high current beam operations, in order to retrieve beam profile distribution and power density distribution of both static and raster beam, imposing a large numerical aperture (NA), but also to transport the image at more than 15m distance where radiation level is compatible with camera and pc stable operation and human access during commissioning and neutron production.

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THPME169

Status of the New Beam Size Monitor at SLS

alignment, emittance, laser, radiation

3662

J. Breunlin, Å. Andersson
MAX-lab, Lund, Sweden
N. Milas
LNLS, Campinas, Brazil
M. Rohrer, A. Saá Hernández, V. Schlott, A. Streun
PSI, Villigen PSI, Switzerland

The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required a beam size monitor with the ability to verify a sub-pmrad vertical emittance. This corresponds to a beam height of less than 4 μm. Within the TIARA Work Package ‘SLS Vertical Emittance Tuning’ a new beam size monitor was designed and built. The monitor is based on the imaging of the pi-polarized synchrotron radiation (SR) in the visible and UV spectral ranges. Besides imaging the monitor provides interferometric methods using vertically or horizontally polarized SR. With these complementary methods the consistency of beam size measurements is verified. An intermediate configuration of the monitor beamline using a lens as the focusing element has been commissioned in 2013. With this setup a vertical beam size of 4.8±0.5 μm, corresponding to a vertical emittance of 1.7±0.4 pmrad has been measured. During 2014 the monitor was commissioned in its final configuration with a toroidal mirror. The use of reflective optics allows wider bandwidth imaging and thus higher intensity. We report on challenges during commissioning and present first images of SR taken with the toroidal mirror.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME169

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THPME173

Beam-based Measurements of the CPS Wire Scanner Precision and Accuracy

emittance, synchrotron, simulation, 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.

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THPME184

Improvement of Beam Imaging Systems through Optics Propagation Simulations

simulation, radiation, 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.

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THPRI010

FCC-ee Final Focus with Chromaticity Correction

dynamic-aperture, sextupole, collider, lattice

3782

H. Garcia, R. Tomás, R. Tomás
CERN, Geneva, Switzerland

A 100 km circular electron-positron collider is considered as one of the possible future high energy facilities. In order to achieve a high luminosity, strong beam focusing at the Interaction Point is used requiring the correction of the chromatic aberrations. In this paper we study preliminary designs of a Final Focus System for the TLEP collider with chromatic correction. Beam orbit stability and dynamic aperture calculations are also presented.

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