IPAC2016 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOYAA01	Commissioning of the MAX IV Light Source	storage-ring, injection, lattice, vacuum	11
	M. Eriksson, E. Al-Dmour, Å. Andersson, M.A.G. Johansson, S.C. Leemann, L. Malmgren, P.F. Tavares, S. Thorin MAX IV Laboratory, Lund University, Lund, Sweden
	This presentation reports on the beam commissioning status of MAX IV, experience gained and lessons learned, as well as future plans.
	Slides MOYAA01 [6.682 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOYAA01
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MOZA02	Design and Optimization Strategies of Nonlinear Dynamics in Diffraction-limited Synchrotron Light Sources	sextupole, lattice, optics, resonance	33
	R. Bartolini DLS, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	This talk introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.
	Slides MOZA02 [4.952 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOZA02
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MOPMB011	ROSE, Measuring the Full 4D Transverse Beam Matrix of Ion Beams	ion, vacuum, coupling, detector	98
	M.T. Maier, X. Du, P. Gerhard, L. Groening, S. Mickat, H. Vormann, C. Xiao GSI, Darmstadt, Germany
	A ROtating System for Emittance measurements ROSE, to measure the full 4 dimensional transverse beam matrix of an ion beam has been developed and commissioned. Different ion beams behind the HLI at GSI have been used in two commissioning beam times. All technical aspects of ROSE have been tested, ROSE has been benchmarked against existing emittance scanners for horizontal and vertical projections, and the method, hard-, and software to measure the 4D beam matrix has been upgraded, refined, and successfully commissioned. The inter plane correlations of the HLI beam have been measured, yet as no significant initial correlations were found to be present, controlled coupling of the beam by using a skew triplet has been applied and confirmed with ROSE. The next step is to use ROSE to measure and remove the known inter plane correlations of a uranium beam before SIS18 injection.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB011
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MOPMB019	Quadrupole Scan Emittance Measurements for the ELI-NP Compton Gamma Source	electron, quadrupole, linac, laser	126
	A.R. Rossi, A. Bacci, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy E. Chiadroni, C. Vaccarezza, A. Variola INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy C. Curatolo, I. Drebot Universita' degli Studi di Milano e INFN, Milano, Italy A. Giribono, A. Mostacci University of Rome La Sapienza, Rome, Italy V. Petrillo, M. Rossetti Conti Universita' degli Studi di Milano & INFN, Milano, Italy
	The high brightness electron LINAC of the Compton Gamma Source at the ELI Nuclear Physics facility in Romania is accelerating a train of 32 bunches with a nominal charge of 250 pC and nominal spacing of 16 ns. To achieve the design gamma flux, all the bunches along the train must have the designed Twiss parameters. Beam sizes are measured with optical transition radiation monitors, allowing a quadrupole scan for Twiss parameters measurements. Since focusing the whole bunch train on the screen may lead to permanent screen damage, we investigated non-conventional scans such as scans around a maximum of the beam size or scans with a controlled minimum spot size. This paper discusses the implementation issues of such a technique in the actual machine layout.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB019
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MOPMB022	Conceptual Design for SR Monitor in the FCC Beam Emittance (Size) Diagnostic	extraction, diagnostics, vacuum, brightness	133
	T.M. Mitsuhashi, K. Oide KEK, Ibaraki, Japan F. Zimmermann CERN, Geneva, Switzerland
	A conceptual design for emittance diagnostics through a beam size measurement using the synchrotron radiation (SR) is studied for the FCC. For the FCC-ee, a X-ray interferometer is propose to measure a nano-radian order vertical beam size. Also conceptual design of SR monitor is studied for FCC-hh. In the FCC-hh, visible SR will emitted from bending magnet in the energy range from the injection (3TeV) to top energy (50TeV). Hard X-ray SR will only available in the energy upper than 30TeV. The various instrumentations using the visible SR is usable for all energy range. Around the top energy, the X-ray pinhole camera will convenient for beam diagnostics of emittance through the beam size measurement.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB022
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MOPMB028	Development of Beam Diagnostic System for the SPring-8 Upgrade	diagnostics, radiation, beam-diagnostic, photon	149
	H. Maesaka, T. Ohshima, Y. Otake RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Dewa, T. Fujita, K. Kobayashi, M. Masaki, S. Matsubara, T. Nakamura, S. Sasaki, S. Takano JASRI/SPring-8, Hyogo-ken, Japan
	The goal of the beam diagnostic system for the SPring-8 upgrade is to deliver brilliant X-rays enabled by the new low-emittance ring to experimental stations with ultimate stability. Developments of accurate electron and photon beam position monitors (EBPM and XBPM, respectively) with both short and long-term stability are the most critical. The EBPM sensitivity is also crucial for low-current beam commissioning to accomplish the first beam storage in the ring. We designed a button electrode to obtain sufficiently high-intensity signals while suppressing high-Q trapped modes leading to impedance and heating issues. We also designed a precise EBPM block and a rigid support to achieve mechanical accuracy and stability. Another challenge is the development of a reliable and stable XBPM, which should be an accurate reference for an orbit feedback without any photon-energy dependences. A significant improvement of a blade-type XBPM or an invention of a novel XBPM detecting the core of an intense X-ray beam are necessary. The other diagnostic instrumentations can be utilized for the new ring with minor improvements.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB028
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MOPMB034	Design and Application of Double-slit Emittance Meter for C-ADS Proton Beams	rfq, proton, background, instrumentation	164
	L. Yu, Y.F. Sui, J.X. Zhao, D.C. Zhu IHEP, Beijing, People's Republic of China
	To reduce the beam loss in the high current linac, beam transverse emittance is a key value which has to be characterized. At Institute of High Energy Physics (IHEP) in Beijing the C-ADS project has started beam commissioning. A newly developed double-slit emittance meter (DEM) for pulsed proton beam from the (RFQ) has been installed in the beam line. In this paper principal of operation, instrumentation and programming of emittance meter are discussed. The emittance measurement has been carried out with the newly developed DEM at a beam energy of 3.2 MeV and a beam current of 10 mA. Typical rms emittance for x and y direction are measured to be 0.1303 and 0.1347 π mm mrad，which are well below the design standard of the RFQ.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB034
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MOPMB040	Design of the Beam Diagnostics System for a New IR-FEL Facility at NSRL	diagnostics, FEL, laser, cavity	181
	J.H. Wei, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, T.Y. Zhou, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (21327901, 11105141, 11575181) A new IR-FEL has been commissioned at NSRL. This facility provides a final electron energy from 20 to 70 MeV, beam bunch with a macro-pulse length of 5~10 μs and a general micro-pulse repetition rate of 238 MHz, pulsed radiation with up to 100 mJ at about 0.3%~3% FWHM bandwidth. So a diagnostics system is necessary to monitor the performance of the bunch and the character of the FEL radiation, such as the beam position and profile, emittance, energy spread, laser intensity, etc. The beam diagnostics system mainly consists of Flags, a diagnostics beam line, BPMs, pop-in monitors and a FEL monitor system. This paper introduces the construction of this diagnostics system. Corresponding author: ylyang@ustc.edu.cn
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB040
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MOPMB052	On-axis Injection using a Sin Wave RF Kicker	kicker, injection, storage-ring, lattice	211
	B.C. Jiang, Y.B. Leng, S.Q. Tian, L.Y. Yu, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	On-axis injection is one of the critical issues for an ul-tra-low emittance storage ring which holds a rather small dynamic aperture. In order to reduce the challenges of the fast pulsed kicker design, a sin wave RF kicker is studied which is suitable for longitudinal on-axis injection. Since the injected bunch is longitudinally apart from the stored bunches, the location of the stored bunches can be at the π knot of the sin wave, while the injected bunches are launched at a phase around π/2+n·π. At this situation the injected bunches will receive a transverse kick, however the store bunches are almost un-affected.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB052
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MOPMB060	Upgrade of the LHC Schottky Monitor, Operational Experience and First Results	pick-up, proton, ion, injection	226
	M. Betz, O.R. Jones, T. Lefèvre, M. Wendt CERN, Geneva, Switzerland
	The LHC Schottky system allows the measurement of beam parameters such as tune and chromaticity in an entirely non-invasive way by extracting information from the statistical fluctuations in the incoherent motion of particles. The system was commissioned in 2011 and provided satisfactory beam-parameter measurements during LHC run 1 for lead-ions. However, for protons its usability was substantially limited due to strong interfering signals originating from the coherent motion of the particle bunch. The system has recently been upgraded with optimized travelling-wave pick-ups and an improved 4.8~GHz microwave signal path, with the front-end and the triple down-mixing chain optimized to reduce coherent signals. Design and operational aspects for the complete system are shown and the results from measurements with LHC beams in Run II are presented and discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB060
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MOPMR012	Studies of Buffer Gas Cooling of Ion Beams in an RFQ Cooler and Their Transport to the EBIS Charge Breeder	ion, rfq, simulation, radio-frequency	248
	K.H. Yoo, M. Chung UNIST, Ulsan, Republic of Korea H.J. Son IBS, Daejeon, Republic of Korea
	In rare isotope accelerator facilities, an RFQ cooler is often used to manipulate ions. The RFQ cooler is a de-vice to effectively cool and confine ions in gaseous envi-ronment. The RFQ cooler provides a radial electric force to the beam by applying RF voltages to the quadrupole electrode structures, and axial force by applying different DC voltages to the segmented electrodes. The ions are trapped inside the potential well of the RFQ cooler formed by the DC fields, so that they have more colli-sions with the buffer gas. Several important parameters such as transverse emittance can be improved when ion beams are extracted from the RFQ cooler. In order to design an efficient RFQ cooler, which can properly match the ion beams into the EBIS charge breeder, it is essential to analyze evolutions of the transverse emittance and transmission efficiency through the RFQ cooler. Moreo-ver, to minimize emittance growth and maximize trans-mission efficiency, the beam transport line to the EBIS charge breeder needs to be optimized. In this work, we study the methods to apply the mechanism of buffer gas cooling in RFQ cooler to G4beamline and the beam transport line to EBIS charge breeder to TRACK.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR012
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MOPMR022	Beam-based Alignment of CLIC Accelerating Structures Utilizing Their Octupole Component	octupole, collider, linear-collider, linac	280
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden
	Alignment of the accelerating structures is essential for emittance preservation in long linear accelerators such as the Compact Linear Collider (CLIC). The prototype structures for CLIC have four radial waveguides connected to each cell for damping wakefields and this four-fold symmetry is responsible for an octupole component of the radio-frequency fields, phase-shifted 90 degrees with respect to the accelerating mode. The octupole field causes a nonlinear dependence of the transverse beam deflection with respect to the position within the accelerating structure. By transversely moving the beam with two upstream steering magnets, and observing the deflection with beam position monitors or screens, the electromagnetic center of the structure can be found. We discuss the applicability of this method for aligning the beam in the accelerating structures.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR022
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MOPMR025	Beam Size Estimation from Luminosity Scans at the LHC During 2015 Proton Physics Operation	luminosity, proton, operation, experiment	290
	M. Hostettler, G. Papotti CERN, Geneva, Switzerland M. Hostettler LHEP, Bern, Switzerland
	As a complementary method for measuring the beam size for high-intensity beams at 6.5 TeV flat-top energy, beam separation scans were done regularly at the CERN Large Hadron Collider (LHC) during 2015 proton physics operation. The luminosities measured by the CMS experiment during the scans were used to derive the convoluted beam size and orbit offset bunch-by-bunch. This contribution will elaborate on the method used to derive plane-by-plane, bunch-by-bunch emittances from the scan data, including uncertainties and corrections. The measurements are then compared to beam size estimations from absolute luminosity, synchrotron light telescopes, and wire scanners. In particular, the evolution of the emittance over the course of several hours in collisions is studied and bunch-by-bunch differences are highlighted.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR025
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MOPMR026	Beam Instrumentation Performance during Commissioning of CERN's Linac-4 to 50 MeV and 100 MeV	laser, linac, DTL, detector	293
	U. Raich, T. Hofmann, F. Roncarolo CERN, Geneva, Switzerland
	Linac-4, a 140 MeV H-linear accelerator is designed to replace the aging 50 MeV proton Linac. It will consist of an H-source and 45 keV LEBT, an RFQ and 3 MeV MEBT with a chopper, 3 drift tube linac (DTL) tanks accelerating the beam to 12, 30 and 50 Mev, cavity coupled structures (CCDTL) accelerating it to 100 MeV and a pi mode structure bringing it to its design energy of 160 MeV. This paper reports on the commissioning of the DTL and CCDTL with 2 dedicated temporary measurement lines, the first one adapted to the 12 MeV beam while the second one is dedicated to characterize the 50 MeV and the 100 MeV beams. The beam diagnostic devices used in these lines is described as well as results obtained.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR026
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MOPMR027	Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements	detector, vacuum, luminosity, real-time	296
	M.N. Rihl, A. Alexopoulos, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, V. Salustino Guimaraes, B. Salvant, R. Veness, S. Vlachos CERN, Geneva, Switzerland A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, P. Hopchev, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu EPFL, Lausanne, Switzerland R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig RWTH, Aachen, Germany
	Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed*, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed. LHCb collaboration, Journal of Instrumentation, 9, P12005 ** P. Hopchev in Proc. of IPAC 2014, June 15-20, 2014, Dresden Germany
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR027
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MOPMR028	Emittance Characterisation of High Brightness Beams in the CERN PS	proton, brightness, synchrotron, extraction	299
	G. Sterbini, J.F. Comblin, V. Forte, A. Guerrero, E. Piselli CERN, Geneva, Switzerland V. Forte Université Blaise Pascal, Clermont-Ferrand, France
	Measurements in the CERN Proton Synchrotron showed that achieving the required accuracy for the emittance characterisation of high brightness beams is challenging. Some of the present limits can be related to systematic errors in the wire scanner calibration or, for the horizontal emittance determination, in the assumptions adopted while deconvoluting the contribution of the longitudinal plane from the measured transverse profile. We present in this paper the results of a beam-based test of the wire scanner calibration and of a general numerical deconvolution algorithm to compute the betatronic profile starting from the measured ones. In addition to the bunch train average emittance, a bunch-by-bunch transverse emittance measurement would increase the potential to understand, optimise and monitor the beam performance. In 2015 the first PS bunch-by-bunch measurement chain was setup. The results are reported and discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR028
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MOPMR039	Review of Emittance Diagnostics for Space Charge Dominated Beams for AWAKE e^- Injector	space-charge, quadrupole, focusing, radiation	337
	O. Mete Apsimon, G.X. Xia UMAN, Manchester, United Kingdom S. Döbert CERN, Geneva, Switzerland C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: This work is supported by the Cockcroft Institute Core Grant and STFC. For a low energy, high intensity beam, total beam emittance is dominated by defocusing space charge force. This is most commonly observed in photo-injectors. In this low energy regime, emittance measurement techniques such as quadrupole scans fail as they consider the beam size only depends on optical functions. The pepper-pot method is used for 2D emittance measurements in a single shot manner. In order to measure the beam emittance in space charge dominated regime by quadrupole scans, space charge term should be carefully incorporated into the transfer matrices. On the other hand, methods such as divergence interferometry via optical transition radiation (OTRI), phase space tomography using 1D projections of quadrupole scans can be suitably applied for such conditions. In this paper, the design of a versatile pepper-pot system for AWAKE experiment at CERN is presented for a wide range of bunch charges from 0.1 to 1nC where the space charge force increases significantly. In addition, other aforementioned methods and respective algorithms are introduced as alternative methods.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR039
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MOPMR048	Emittance Measurements and Operation Optimization for ECR Ion Sources	ion, ion-source, ECR, cyclotron	361
	V. Tzoganis, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom O. Kamigaito, T. Nagatomo, T. Nakagawa, V. Tzoganis RIKEN Nishina Center, Wako, Japan V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: RIKEN IPA scheme and Cockcroft Institute Core Grant Electron Cyclotron Resonance (ECR) ion sources supply a broad range of ions for post acceleration in cyclotrons. Here, an effort to improve the beam transfer from RIKEN's 18 GHz ECR ion source to the Low Energy Beam Transfer (LEBT) line and an optimization of the performance of the ion source is presented. Simulation studies have shown that less than 20% of the beam is currently transferred. The first goal is to measure the transverse beam emittance in real time. The emittance monitor designed and fabricated for this purpose utilizes a pepper pot plate followed by a transparent scintillator and a CMOS camera for image capture. The second goal is to find the optimal operating point of the ion source by sweeping parameters such as RF power, vacuum pressure, extraction electrode position and voltage. To this extent, modifications of the ion source took place, as well as a measurement of the magnetic field inside the ion source. In this contribution the results of the emittance and other operating parameters measurements, as well as the design details of the emittance monitor are presented
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR048
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MOPMW029	Analysis of Transverse Field Induced by Curved Beryllium Window in Muon Ionization Cooling Cavity	cavity, Windows, acceleration, focusing	457
	T.H. Luo, D. Li LBNL, Berkeley, California, USA
	The beryllium windows are used in muon ionization cooling cavity to increase the cavity shunt impedance. The windows are curved for predictable thermal deformation. This curvature also introduces transverse field, which will affect the transverse beam emittance. In this paper, we will analyze this transverse field and evaluate its effect on the emittance cooling.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMW029
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MOPMY001	Beam Dynamics Analysis for the Ultra-fast Kicker in Circular Cooler Ring of JLEIC	kicker, electron, cavity, recirculation	510
	Y.L. Huang IMP/CAS, Lanzhou, People's Republic of China R.A. Rimmer, H. Wang, S. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. An ultra-fast kicker system consist of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency, thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mA - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesis such a kicker waveform will be discussed with the comparison of beam dynamics tracking in Elegant.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY001
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MOPOR004	Recent Progress of 1-MW Beam Tuning in the J-PARC 3-GeV RCS	resonance, injection, scattering, power-supply	592
	H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV RCS started 1 MW beam test from October 2014, and successfully achieved a 1 MW beam acceleration in January 2015. Since then, a large fraction of our effort has been focused on reducing and managing beam losses. This paper presents the recent progress of 1 MW beam tuning, especially focusing on our approaches to beam loss issues, such as space-charge induced beam loss and foil scattering beam loss during charge-exchange injection, etc.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR004
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MOPOR017	First Year Performance of the TPS Booster Ring	booster, synchrotron, linac, storage-ring	634
	H.-J. Tsai, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.Y. Liao, Y.-C. Liu, G.-H. Luo, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is a 3-GeV low- emittance light source of circumference 518.4 m. The booster ring is in the same tunnel with the storage ring; its circumference at 496.8 m makes it the largest booster ring in operation in existing light sources. Since the successful commissioning at the end of 2014, the TPS booster ring has been optimized in performance for routine operation. In this paper, we present the system upgrade and the improvement of the ramping procedure to increase the capture and ramping efficiency of the beam charge, the characterization of the optics, etc.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR017
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MOPOR019	Beta Function Measurement and Resonances Induced by Space Charge Force and Lattice Magnets	resonance, space-charge, lattice, simulation	641
	K. Ohmi, K.G. Sonnad KEK, Ibaraki, Japan
	J-PARC MR has been operated at tune (ν_x,ν_y)=(22.40,20.75). A new operating point around (21.4,21.4) has been proposed by simulation studies on space charge effect since 2013. Machine experiments at the operating point has been performed since 2014 and many encouraging results are being obtained. We discuss why new operating point is better than present one from view point of space charge effects.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR019
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MOPOR021	Space Charge Studies with High Intensity Single Bunch Beams in the CERN SPS	injection, brightness, resonance, space-charge	644
	H. Bartosik, F. Schmidt CERN, Geneva, Switzerland A. Oeftiger EPFL, Lausanne, Switzerland M. Titze HZB, Berlin, Germany
	In order to reach the target beam parameters of the LHC injectors upgrade (LIU) project the beam degradation due to losses and emittance growth on the long injection plateau of the SPS needs to be minimized. A detailed study of the dependence of losses, transverse emittance blow-up and transverse beam tail creation as function of the working point is presented here for a high brightness single bunch beam with a vertical space charge tune spread of about 0.2 on the 26 GeV injection plateau. The beam behaviour close to important betatron resonances is characterised and a region in the tune diagram with minimal beam degradation is identified. Implications about the performance for LIU beams are discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR021
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MOPOR022	Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps	electron, operation, octupole, injection	648
	H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk CERN, Geneva, Switzerland
	Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR022
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MOPOR023	Flat Bunches with a Hollow Distribution for Space Charge Mitigation	space-charge, synchrotron, resonance, injection	652
	A. Oeftiger, H. Bartosik, A. Findlay, S. Hancock, G. Rumolo CERN, Geneva, Switzerland A. Oeftiger EPFL, Lausanne, Switzerland
	Funding: CERN, Doctoral Studentship EPFL, Doctorate Longitudinally hollow bunches provide one means to mitigate the impact of transverse space charge. The hollow distributions are created via dipolar parametric excitation during acceleration in CERN's Proton Synchrotron Booster. We present simulation work and beam measurements. Particular emphasis is given to the alleviation of space charge effects on the long injection plateau of the downstream Proton Synchrotron machine, which is the main goal of this study.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR023
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MOPOR024	Evolution of High Intensity Beams in the CERN PS Booster after H⁻ Injection and Phase Space Painting	injection, space-charge, booster, lattice	656
	M. Cieslak-Kowalska, J.L. Abelleira, E. Benedetto, C. Bracco CERN, Geneva, Switzerland
	With the LHC Injector Upgrade (LIU) project, the injection energy of PS Booster (PSB) ' first circular accelerator in the LHC injector chain ' will be raised from 50 MeV to 160 MeV and the present multiturn injection will be upgraded to H⁻ injection with transverse and longitudinal painting. In the scope of this project, it is planned to double the beam intensities, profiting from the fact that the βγ2 factor will be two times larger (0.35 at 50 MeV and 0.71 at 160 MeV), so the resulting tune spread driven by a direct space charge should remain similar. This paper describes the feasibility to double the intensity of high intensity and large emittance beams, looking into the evolution under space charge and taking into account losses constrains in the ring and in the extraction lines.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR024
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MOPOR025	3D Emittances Tailoring Techniques and Optimization with Space Charge for the Future CERN PS Booster Operations with Linac4	injection, coupling, simulation, linac	660
	V. Forte, J.L. Abelleira, E. Benedetto, C. Bracco, M. Cieslak-Kowalska, G.P. Di Giovanni CERN, Geneva, Switzerland
	In the frame of the LIU (LHC Injectors Upgrade) project, the CERN PS Booster is going to be renovated to host a new H⁻ charge-exchange injection from the Linac4. One important feature of the new injection scheme is the possibility to tailor a wide range of 3D emittances for CERN's different users in an intensity span in the order of 5·10⁹ to 1.6·10¹³ protons per PSB ring. This paper gives an overview of 3D multi-turn injection techniques, focusing on the future LHC beams, which aim at reaching high brightness, and on highest intensity beams (ISOLDE), where losses are the main concern. Complete RF capture simulations and transverse injection maps, including space charge effects, are presented and also intended to be used during the commissioning with Linac4.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR025
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MOPOR032	Using of the MENT Method for Reconstruction of 2D Particle Distributions in IFMIF Accelerators	linac, SRF, simulation, HOM	668
	P.A.P. Nghiem, N. Chauvin, L. Ducrot, M. Valette CEA/DSM/IRFU, France
	Beam particles are characterized by their coordinates in real spaces or phase spaces that are at least two-dimensional. It is often necessary to reconstruct such a 2D-distribution from the knowledge of only its projections on some axes, either for making use of tomography measurement results or for setting up an input beam for transport simulations. In this article, the use of the MENT (Maximum Entropy) reconstruction method is reported for the IFMIF accelerators where high intensity beam distributions are far from Gaussian ones.
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MOPOR035	Space Charge Neutralization Studies with H⁻ Beam in Low Energy Beam Transport Test Stand	space-charge, ion, ion-source, rfq	677
	S. Artikova Private Address, Tsukuba, Japan K. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Shibata, A. Takagi KEK, Tokai, Ibaraki, Japan
	J-PARC is intensity-upgraded up to pulse current of 50 mA of H⁻ beam. Two-solenoid based LEBT test stand is being built to support the operation of J-PARC linac. It imitates the actual LEBT of linac, yet contains the diagnostics chamber composed of horizontal and vertical beam emittance-meters and Faraday-cup for the current measurement. Vacuum composition of LEBT is predominantly H2 gas. The pressure inside the LEBT can be varied by the differential pumps allowing us to study the beam phase space evolution under space charge effects. The measurements of the beam phase space emittance were made as a function of the residual gas pressure. This paper presents the results and discussion on beam space charge neutralization and its effect on the beam phase space emittance.
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MOPOR038	Implications of Resonantly Driven Higher Order Modes on the ESS Beam	HOM, cavity, simulation, linac	683
	A. Farricker, R.M. Jones, N.Y. Joshi UMAN, Manchester, United Kingdom S. Molloy ESS, Lund, Sweden
	The European Spallation Source (ESS) in Lund, Sweden, will be a facility for fundamental physics studies of atomic structure using a spallation source of unparalleled brightness. To achieve this end, a 2.86 ms long pulsed proton beam will be accelerated up to a final energy of 2 GeV using three suites of superconducting cavities. If a Higher Order Mode (HOM) lies on a harmonic of the bunch frequency the HOM will be resonantly driven. This will dilute the beam quality significantly. Errors in fabricating these cavities are inevitable, and this sets a tolerance on how close the HOM can be within a harmonic of the bunch frequency. The baseline design for ESS requires HOMs to be at least 5 MHz from a machine line. Here we provide details of several finite element electromagnetic simulations on the HOMS anticipated in these ESS cavities. We analyse their impact on the beam emittance using a drift-kick-drift model with the potential for relaxed tolerances.
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MOPOW012	Transverse Coherence and Fundamental Limitation on the Pointing Stability of X-ray FELs	FEL, radiation, electron, photon	735
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	The radiation from SASE FEL has always limited value of the degree of transverse coherence. When transverse size of the electron beam significantly exceeds diffraction limit, the mode competition effect does not provide the selection of the ground mode, and spatial coherence degrades due to contribution of the higher azimuthal modes. An important consequence of this effect are fluctuations of the spot size and pointing stability of the photon beam. These fluctuations are fundamental and originate from the shot noise in the electron beam. The effect of pointing instability becomes more pronouncing for shorter wavelengths. We analyze in detail the case of optimized SASE FEL and derive universal dependencies applicable to all operating and planned x-ray FELs. We show that the hard x-ray FELs driven by low energy beams may exhibit poor spatial coherence and bad pointing stability. * E.L. Saldin, E.A. Schneidmiller and M.V. Yurkov, Opt. Commun. 281(2008)1179. ** E.A. Schneidmiller and M.V. Yurkov, Proc. FEL2015 Conference, Daejeon, Korea, 2015, TUP021.
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MOPOW036	Design Optimization of an X-band based FEL	linac, FEL, simulation, gun	793
	A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey A. Latina, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland Z. Nergiz Nigde University, Nigde, Turkey
	A design effort for a new generation of compact, cost-effective, power-efficient FEL facilities, based on X-band technology, has been launched. High-frequency X-band acceleration implies strong wakefields, tight alignment and mechanical tolerances, and challenging stability issues. In this paper a design is proposed for the injector and the linacs, including the two bunch compressors. RF gun and injector simulations have been performed, successfully meeting the stringent requirements in terms of minimum projected emittance, sliced emittance and minimum bunch length. In the design of the linac and bunch compressors wakefield effects and misalignment have been taken into account. Start-to-end tracking simulations through the optimized lattice are presented and discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW036
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MOPOW050	Study of Lower Horizontal Emittance Optics in the Present Soleil Storage Ring	quadrupole, lattice, optics, dynamic-aperture	827
	H.C. Chao, P. Brunelle, A. Nadji, L.S. Nadolski, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	With the aim of delivering a lower horizontal emittance beam to the users of the present SOLEIL ring, a systematic lattice study is carried out. The goal is to discover feasible optics solutions having the horizontal emittance notably lower than the present value of 3.9 nm rad, while fulfilling all the physical requirements and without changing the current magnet structure in the lattice. The strategy adopted is a cell-wise optimization of the linear lattices in the two types of double-bend cells that constitute the SOLEIL ring. In the second step they are concatenated via finer matching. A global scan of the 5 quadrupole families for the search of stable solutions is performed. The statistical properties are given. One can easily select possible solutions without matching. For the second type of cell having 10 quadrupole families, another scan of quadrupoles and a matching using a quadrupole triplet are applied for linear optics characteristics. Finally, the nonlinear optimization is performed with modern nonlinear optimization algorithms.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW050
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MOPOW051	High Level Control Command for ThomX Transfer Line	linac, quadrupole, optics, TANGO	830
	C. Bruni, I. Chaikovska, S. Chancé, N. Delerue, A.R. Gamelin, H. Guler, H. Monard, C. Vallerand LAL, Orsay, France A. Loulergue SOLEIL, Gif-sur-Yvette, France
	ThomX Compact X ray source is a 50 MeV storage ring, and a linear accelerator based on a photo-injector. As the electron beam in the ring will not be damped by synchrotron radiation, the transfer line should rely on a precise injection in the ring. In order to fulfill this requirement, especially in terms of optics function and orbit correction, different tools have been prepared and tested on the accelerator toolbox of Matlab Middle Layer. We will present the different tools and the underlying physics for the ThomX transfer line.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW051
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MOPOY006	Preparations for Upgrading the RF Systems of the PS Booster	cavity, impedance, operation, feedback	853
	S.C.P. Albright, D. Quartullo, E.N. Shaposhnikova CERN, Geneva, Switzerland
	The accelerators of the LHC injector chain need to be upgraded to provide the HL-LHC beams. The PS Booster, the first synchrotron in the LHC injection chain, uses three different RF systems (first, second and up to tenth harmonic) in each of its four rings. As part of the LHC Injector Upgrade the current ferrite RF systems will be replaced with broadband Finemet cavities, increasing the flexibility of the RF system. A Finemet test cavity has been installed in Ring 4 to investigate its effect on machine performance, especially beam stability, during extensive experimental studies. Due to large space charge impedance Landau damping is lost through most of the cycle in single harmonic operation, but is recovered when using the second harmonic and controlled longitudinal emittance blow-up. This paper compares beam parameters during acceleration with and without the Finemet test cavity. Comparisons were made using beam measurements and simulations with the BLonD code based on a full PS Booster impedance model. This work, together with simulations of future operation, have provided input for the decision to adopt a fully Finemet RF system.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY006
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MOPOY009	ELENA: Installations and Preparations for Commissioning	antiproton, electron, experiment, extraction	860
	C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, R. Ostojić, S. Pasinelli, G. Tranquille CERN, Geneva, Switzerland W. Oelert Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany
	The Extra Low Energy Antiproton ring (ELENA) is a small 30 m circumference synchroton under construction at CERN to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. Installation of the machine and lines needed for the commissioning of the ring are ongoing and commissioning is expected to start around mid-2016. The aim is to complete ELENA ring commissioning in November followed by the installation of new electrostatic transfer lines to existing experiments until autumn 2017. Status of ELENA installations and preparations for commissioning will be reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY009
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MOPOY013	Modeling Longitudinal Dynamics in the Fermilab Booster Synchrotron	booster, impedance, synchrotron, simulation	873
	J.-F. Ostiguy, C.M. Bhat, V.A. Lebedev Fermilab, Batavia, Illinois, USA
	Funding: Work performed under U.S. Government contract DE-AC02-07CH11359 The PIP-II project will replace the existing 400 MeV linac with a new, CW-capable, 800 MeV superconducting one. With respect to current operations, a 50% increase in beam intensity in the rapid cycling Booster synchrotron is expected. Booster batches are combined in the Recycler ring; this process limits the allowed longitudinal emittance of the extracted Booster beam. To suppress eddy currents, the Booster has no beam pipe; magnets are evacuated, exposing the beam to core laminations and this has a substantial impact on the longitudinal impedance. Noticeable longitudinal emittance growth is already observed at transition crossing. Operation at higher intensity will likely necessitate mitigation measures. We describe systematic efforts to construct a predictive model for current operating conditions. A longitudinal only code including a laminated wall impedance model, space charge effects, and feedback loops is developed. Parameter validation is performed using detailed measurements of relevant beam, rf and control parameters. An attempt is made to benchmark the code at operationally favorable machine settings.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY013
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MOPOY016	HSI RFQ Upgrade for the UNILAC Injection to FAIR	rfq, bunching, simulation, ion	877
	C. Zhang, L. Groening, O.K. Kester, S. Mickat, H. Vormann GSI, Darmstadt, Germany M. Baschke, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main, Germany
	As an injector to the future FAIR facility, the UNILAC accelerator is required to deliver ion beams with high intensities as well as good beam quality. The electrodes of the current HSI RFQ are exhausted and the current RFQ itself is assigned to be one bottle-neck for improving the brilliance performance of the whole linac. Based on the so-called NFSP (New Four-Section Procedure) method, a new RFQ electrode design has been developed and optimized for 20 emA, U⁴⁺ beams at the RFQ entrance. Since only the electrodes will be replaced, the RFQ length has been kept unchanged. Even with a lowered inter-vane voltage, the new RFQ design has achieved better beam performance compared to the previous design. This paper will focus on the performed study with respect to beam dynamics.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY016
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MOPOY017	Upgrade of the Universal Linear Accelerator UNILAC for FAIR	DTL, ion, rfq, operation	880
	L. Groening, A. Adonin, X. Du, R. Hollinger, E. Jäger, M.T. Maier, S. Mickat, A. Rubin, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao, A. Yakushev, C. Zhang GSI, Darmstadt, Germany M. Baschke, H. Hähnel, H. Podlech, U. Ratzinger, A. Seibel, R. Tiede IAP, Frankfurt am Main, Germany Ch.E. Düllmann, P. Scharrer HIM, Mainz, Germany
	In order to meet the requirements on beam parameters for the upcoming FAIR facility at GSI, the injector linac UNILAC will be upgraded. The activities comprise development of the sources for stable provision of intense uranium beams at a repetition rate of 2.7 Hz, a revision of the beam dynamics layout of the 120 keV/u RFQ, the replacement of the matching section to the 1.4 MeV/u pre-stripper DTL, and enhancement of the gaseous stripping section efficiency. This section shall also include a round-to-flat emittance adaptor to prepare the beam for injection into the synchrotron SIS18 which has a flat transverse injection acceptance. Finally, the upgrade includes the complete replacement of the 40 year old 11.4 MeV/u Alvarez-type post-stripper DTL with a new DTL, preferably using Alvarez-type cavities with improved beam focusing features, as well as its rf-power alimentations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY017
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MOPOY027	Emittance Measurement with Wire Scanners at C-ADS Injector-I	rfq, simulation, beam-transport, background	910
	H. Geng, C. Meng, Y.F. Sui, F. Yan, L. Yu, Y.L. Zhao IHEP, Beijing, People's Republic of China
	The transverse emittance at C-ADS injector-I has been measured by the wire scanners at the Medium Energy Beam Transport-I (MEBT1). We have studied the effect of different fitting methods for obtaining the beam sizes on the emittance result, the result will be presented in this paper. The validation study of the quad-scan method with the presence of space charge effect at 10 mA will also be shown, and finally the quad-scan results will be compared with the multi-wire results.
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MOPOY029	Transverse Emittance Measurements in CSNS Linac	focusing, quadrupole, space-charge, linac	916
	Z.P. Li, Y. Li, J. Peng, S. Wang IHEP, Beijing, People's Republic of China
	Commissioning of the front-end of the linac at CSNS has been accomplished. Double scanning slit system and wire-scanners were employed to carry out the transverse emittance measurements in both low energy beam transport (LEBT) and medium energy beam transport (MEBT). Different results of different measurement methods are presented and compared. Corresponding codes were developed for each of the emittance measurement methods.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY029
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MOPOY031	Emittance Measurement with Double-Slit Method in CADS Injector-I	solenoid, rfq, linac, simulation	922
	C. Meng, H. Geng, Z. Xue, F. Yan, L. Yu, Y.L. Zhao IHEP, Beijing, People's Republic of China
	The C-ADS accelerator is a CW (Continuous-Wave) proton linac with 1.5 GeV in beam energy, 10 mA in beam current, and 15 MW in beam power. CADS Injector-I accelerator is a 10-mA 10-MeV CW proton linac, which uses a 3.2-MeV normal conducting 4-Vane RFQ and superconducting single-spoke cavities for accelerating. The 5MeV test stand of CADS accelerator Injector I is composed of an ion source, a LEBT, a 325MHz RFQ, a MEBT, a cryogenic module (CM1) of seven SC spoke cavities (β=0.12) , seven SC solenoids, seven cold BPMs and a beam dump. Emittance measurement is very important for the understanding of beam behavior and matching to the next accelerating section. Detailed emittance measurement with double-slit method after CM1 are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY031
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MOPOY047	Studies of Ultimate Intensity Limits for High Power Proton Linacs	linac, proton, DTL, rfq	951
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom M.O. Boenig, A.E. Geisler, O. Heid Siemens AG, Erlangen, Germany I.V. Konoplev, A. Seryi, S.L. Sheehy JAI, Oxford, United Kingdom
	Although modern high power proton machines can now routinely deliver MW level operating powers, the next generation accelerators will be required to reach powers orders of magnitude higher. Significant developments will be needed both in technology and in understanding the limits of high intensity operation. The present study investigates the beam dynamics in three experimental linac designs when the beam intensity is increased above current levels such that for CW regimes, beam powers of up to 400 MW can be attained. In the first, a 1 A proton beam is accelerated to 400 MeV using normal conducting structures. In the second, a comparison is made when two front ends accelerate 0.5 A beams to ~20 MeV where they are funnelled to 1 A and accelerated to 400 MeV. Similarly, in the third, two 0.25 A beams are funnelled to 0.5 A and then accelerated in superconducting structures to 800 MeV. In addition, alternative unconventional methods of generating high current beams are also discussed. The further studies that are needed to be undertaken in the future are outlined, but it is considered that the three linac configurations found are sufficiently promising for detailed technical designs to follow.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY047
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MOPOY058	Removing Known SPS Intensity Limitations for High Luminosity LHC Goals	impedance, vacuum, simulation, shielding	989
	E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, P. Cruikshank, B. Goddard, T. Kaltenbacher, A. Lasheen, J. Perez Espinos, J. Repond, B. Salvant, C. Vollinger CERN, Geneva, Switzerland
	In preparation of the SPS as an LHC injector its impedance was significantly reduced in 1999 - 2000. A new SPS impedance reduction campaign is planned now for the High Luminosity (HL)-LHC project, which requires bunch intensities twice as high as the nominal one. One of the known intensity limitations is a longitudinal multi-bunch instability with a threshold 3 times below this operational intensity. The instability is presently cured using the 4th harmonic RF system and controlled emittance blow-up, but reaching the HL-LHC parameters cannot be assured without improving the machine impedance. Recently the impedance sources responsible for this instability were identified and implementation of their shielding and damping is foreseen during the next long shutdown (2019 - 2020) in synergy with two other important upgrades: amorphous carbon coating of (part of) the vacuum chamber against the e-cloud effect and rearrangement of the 200 MHz RF system. In this paper the strategy of impedance reduction is presented together with beam intensity achievable after its realisation. The potential effect of other proposals on remaining limitations is also considered.
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TUOBA03	Application of Differential Evolution Algorithm in Future Collider Optimization	dynamic-aperture, sextupole, lattice, collider	1025
	Y. Zhang IHEP, Beijing, People's Republic of China D. Zhou KEK, Ibaraki, Japan
	Funding: Project U1332108 supported by NSFC. The dynamic aperture of is very limited due to the very small beta at IP in the SuperKEKB. In the storage ring based Higgs factory, the vertical beta function is not so small, but the much larger circumference enlarge the detuning term especially in horizontal direction. It is very hard to optimize the dynamic aperture in the future colliders. The particle loss may comes from different cause for different energy or different transverse coupling. The design of CEPC is still in process. The construction of SuperKEKB is nearly finished, but there still exist some problem which could reduce the performance. There are a few hundred parameters to be varied in the future colliders. The global optimization may be a good way to enlarge the dynamic aperture. Differential Evolution is a very simple population based, stochastic function minimizer which is very powerful at the same time. In this paper we show some application of the algorithm in the two machines. It has the potential to help us optimize the machine.
	Slides TUOBA03 [2.289 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBA03
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TUOCA03	Commissioning of the European XFEL Injector	gun, laser, controls, operation	1044
	F. Brinker DESY, Hamburg, Germany
	The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.
	Slides TUOCA03 [5.182 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA03
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TUOAB02	Conditions for CSR Microbunching Gain Suppression	dipole, lattice, synchrotron, synchrotron-radiation	1057
	C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA S. Di Mitri Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy D. Douglas, R. Li, C. Tennant JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver*. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain. D.Douglas et al, JLAB-ACP-14-1751, S.DiMitri et al, PRL (2013), R.Hajima, NIMA (2004), Y.Jiao et al, PRSTAB (2014) Z.Huang et al, PRSTAB (2004), Saldin et al, NIMA (2004) *C.Tsai et al, FEL'15
	Slides TUOAB02 [6.484 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOAB02
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TUOBB01	Demonstration of Current Profile Shaping using Double Dog-Leg Emittance Exchange Beam Line at Argonne Wakefield Accelerator	quadrupole, dipole, experiment, wakefield	1065
	G. Ha, M.-H. Cho, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, G. Ha, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA P. Piot Fermilab, Batavia, Illinois, USA
	Emittance exchange (EEX) based longitudinal current profile shaping is the one of the promising current profile shaping technique. This method can generate high quality arbitrary current profiles under the ideal conditions. The double dog-leg EEX beam line was recently installed at the Argonne Wakefield Accelerator (AWA) to explore the shaping capability and confirm the quality of this method. To demonstrate the arbitrary current profile generation, several different transverse masks are applied to generate different final current profiles. The phase space slopes and the charge of incoming beam are varied to observe and suppress the aberrations on the ideal profile. We present current profile shaping results, aberrations on the shaped profile, and its suppression.
	Slides TUOBB01 [5.032 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOBB01
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TUPMR020	In-depth Analysis and Optimization of the European Spallation Source Front End Lattice	rfq, solenoid, space-charge, simulation	1274
	Y.I. Levinsen, M. Eshraqi ESS, Lund, Sweden L. Celona, L. Neri INFN/LNS, Catania, Italy
	The European Spallation Source front end will deliver a 62.5 mA beam current of 2.8 ms duration at 352 MHz to the downstream linac, which in turn will produce a 5 MW proton beam onto the target. Such unprecedented beam power requires a high quality beam with accurate and stable beam parameters in order to assure low beam losses and safe transport through the linac. In this paper we present advanced tuning methods for the low energy beam transport and the radio frequency quadrupole.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR020
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TUPMR033	Low Emittance Growth in a LEBT with Un-neutralized Section	ion, ion-source, solenoid, vacuum	1317
	L.R. Prost, J.-P. Carneiro, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy In a Low Energy Beam Transport line (LEBT), the emittance growth due to the beam's own space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report discusses the experimental realization of such a scheme at Fermilab's PXIE, where low beam emittance dilution was demonstrated
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR033
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TUPMR046	Sources of Emittance Growth at the CERN PS Booster to PS Transfer	injection, kicker, optics, betatron	1352
	W. Bartmann, J.L. Abelleira, F. Burkart, B. Goddard, J. Jentzsch, R. Ostojić CERN, Geneva, Switzerland
	The CERN PS Booster (PSB) has four vertically stacked rings. After extraction from each ring, the bunches are recombined in two stages, comprising septum and kicker systems, such that the accumulated bunch train is injected through a single line into the PS. Bunches from the four rings go through a different number of vertical bends, which leads to differences in the betatron and dispersion functions due to edge focussing. The fast pulsed systems at PSB extraction, recombination and PS injection lead to systematic errors of delivery precision at the injection point. These error sources are quantified in terms of emittance growth and particle loss. Mitigations to reduce the overall emittance growth at the PSB to PS transfer within the LHC injectors upgrade are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR046
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TUPMW002	LHC Luminosity Modeling for RUNII	luminosity, radiation, scattering, proton	1403
	F. Antoniou, G. Arduini, M. Hostettler, M. Lamont, S. Papadopoulou, Y. Papaphilippou, G. Papotti, M. Pojer, B. Salvachua, M. Wyszynski CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project After a long shut-down (LS1), LHC restarted its operation on April 2015 at a record energy of 6.5TeV, achieving soon a good luminosity performance. In this paper, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on the observations, other sources of luminosity degradation are discussed and the model is refined. Finally, based on the experience from runI and runII, the model is used for integrated luminosity projections for the HL-LHC beam parameters.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW002
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TUPMW007	Impact of Long Range Beam-Beam Effects on Intensity and Luminosity Lifetimes from the 2015 LHC Run	luminosity, experiment, hadron, dynamic-aperture	1422
	M.P. Crouch, R.B. Appleby UMAN, Manchester, United Kingdom D. Banfi, C. Tambasco EPFL, Lausanne, Switzerland J. Barranco, R. Bruce, X. Buffat, T. Pieloni, M. Pojer, B. Salvachua, G. Trad CERN, Geneva, Switzerland B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Research supported by the High Luminosity LHC project Luminosity is one of the key parameters that determines the performance of colliding beams in the Large Hadron Collider (LHC). Luminosity can therefore be used to quantify the impact of beam-beam interactions on the beam lifetimes and emittances. The High Luminosity Large Hadron Collider (HL-LHC) project aims to reach higher luminosities, approximately a factor of 7 larger than the nominal LHC at peak luminosity without crab cavities. Higher luminosities are achieved by increasing the bunch populations and reducing the transverse beam sizes. This results in stronger beam-beam effects. Here the LHC luminosity and beam intensity decay rates are analysed as a function of reducing beam separation with the aim of characterising the impact of beam-beam effects on the luminosity and beam lifetime. The analysis and results are discussed with possible application to the HL-LHC upgrade.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW007
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TUPMW008	Evolution of the Beam Parameters during Luminosity Production in the Future Circular Hadron Collider	luminosity, collider, scattering, damping	1426
	X. Buffat, D. Schulte CERN, Geneva, Switzerland
	The evolution of the beam parameters during luminosity production in the Future Circular Hadron Collider (FCC-hh) is described based on basic models of the effect of synchrotron radiations, intra-beam scattering, luminosity burn-off and beam-beam limitations, allowing for an estimation of the luminosity performance in different running scenarios. It is shown that a large variations of the beam parameters is expected during a cycle. Potential operational schemes adapting to these variations are considered.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW008
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TUPMW009	Simulation of Head-on Beam-Beam Limitations in Future High Energy Colliders	simulation, synchrotron, collider, radiation	1430
	X. Buffat, T. Pieloni, C. Tambasco CERN, Geneva, Switzerland J. Barranco, A. Florio EPFL, Lausanne, Switzerland
	The Future Circular Hadron Collider (FCC-hh) project calls for studies in a new regime of beam-beam interactions. While the emittance damping due to synchrotron radiation is still slower than in past or existing lepton colliders, it is significantly larger than in other hadron colliders. The slow reduction of the emittance is profitable for higher luminosity in term of transverse beam size at the interaction points and also to mitigate long-range beam-beam effects, potentially allowing for a reduction of the crossing angle between the beams during the operation. In such conditions, the strength of head-on beam-beam interactions increases, potentially limiting the beam brightness. 4D weak-strong and strong-strong simulations are performed in order to assess these limitations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW009
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TUPMW013	Experimental Demonstration of β* Leveling at the LHC	luminosity, betatron, controls, experiment	1442
	A.A. Gorzawski, D. Mirarchi, B. Salvachua, J. Wenninger CERN, Geneva, Switzerland
	The HL-LHC project foresees to boost the LHC peak luminosity beyond the capabilities of the LHC experimental detectors. Leveling the luminosity down to a constant value that is sustainable for the experiments is therefore the operational baseline of HL-LHC. Various luminosity leveling techniques are available at the LHC. Leveling by adjusting β^, the betatron function at the interaction point, to maintain a constant luminosity is favorable because the beams remain head-on which provides optimal stability from the point of view of collective effects. Smooth leveling by β^ requires however excellent control of the beam orbits and beam losses in the interaction regions since the beam offsets should not vary by more than around one r.m.s. beam size during the process. This leveling scheme has been successfully tested and experimentally demonstrated during the LHC machine development program in 2015. This paper presents results on luminosity leveling over a β^* range from 10 m to 0.8 m and provides an outlook on future developments and use of this technique at the LHC.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW013
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TUPMW022	Modelling and Measurements of Bunch Profiles at the LHC Flat Bottom	lattice, scattering, radiation, damping	1477
	S. Papadopoulou, F. Antoniou, J.E. Muller, Y. Papaphilippou, G. Trad CERN, Geneva, Switzerland
	At the LHC flat bottom the interplay between a series of effects (i.e. intrabeam scattering, longitudinal beam manipulations, non-linearities of the machine, etc) can lead to a population of the tails of the beam distributions, which may become non-Gaussian. This paper presents observations of the evolution of particle distributions in the LHC flat bottom. Novel distribution functions are employed to represent the beam profiles, and used as a guideline for generalising emittance growth rate estimations due to IBS. Finally, an attempt is made to benchmark an IBS Monte-Carlo simulation code, able to track 3D particle distributions, with the measured beam profile evolutions.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW022
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TUPMW034	A 200 MHz SC-RF System for the HL-LHC	cavity, injection, luminosity, impedance	1513
	R. Calaga, R. Tomás CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project A quarter wave β=1 superconducting cavity at 200 MHz is proposed for the LHC as an alternative to the present 400 MHz RF system. The primary motivation of such a system would be to accelerate higher intensity and longer bunches with improved capture efficiency. Advantages related to minimizing electron cloud effects, intra-beam scattering, heating and the possibility of luminosity levelling with bunch length are described. Some considerations related to cavity optimization, beam loading and technological challenges are addressed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW034
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TUPMW035	Performance and Operational Aspects of HL-LHC Scenarios	luminosity, optics, simulation, electron	1516
	L.E. Medina Medrano DCI-UG, León, Mexico R. Tomás CERN, Geneva, Switzerland
	Funding: Research supported by the High Luminosity LHC project. Work supported by the Beam Project (CONACYT, Mexico). Several alternatives to the present HL-LHC baseline configuration have been proposed, aiming either to improve the potential performance, reduce its risks, or to provide options for addressing possible limitations or changes in its parameters. In this paper we review and compare the performance of the HL-LHC baseline and the main alternatives with the latest parameters set. The results are obtained using refined simulations of the evolution of the luminosity with β^*-levelling, for which new criteria have been introduced, such as improved calculation of the intrabeam scattering and the addition of penalty steps to take into account the necessary time to move between consecutive optics during the process. The features of the set of optics are discussed for the nominal baseline.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW035
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TUPMW038	RHIC Operation with Asymmetric Collisions in 2015	proton, operation, injection, cavity	1527
	C. Liu, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, G. Narayan, S.K. Nayak, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, G. Wang, K. Yip, A. Zaltsman, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA S.M. White ESRF, Grenoble, France
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Collisions with beams of highly asymmetric rigidities (proton-Gold and proton-Aluminum) were provided for the RHIC physics programs in 2015. Magnets were moved for the first time in RHIC prior to the run to accommodate the asymmetric beam trajectories during acceleration and at store. A special ramping scheme was designed to keep the revolution frequencies of the beams in the two rings equal. The unique operational experience of the asymmetric run will be reviewed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW038
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TUPMW039	Measurement of the Total Cross Section of Gold-Gold Collisions at sqrt {s_NN}=200 GeV	luminosity, ion, heavy-ion, collider	1530
	W. Fischer, A.J. Baltz, M. Blaskiewicz, K.A. Drees, D.M. Gassner, Y. Luo, M.G. Minty, P. Thieberger BNL, Upton, Long Island, New York, USA I.A. Pshenichnov RAS/INR, Moscow, Russia
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. Heavy ion collision cross sections totaling several hundred barns have been calculated previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). These total cross sections are more than one order of magnitude larger than the geometric ion-ion cross sections, primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for RHIC and the LHC, where some collision products are lost in cryogenically cooled magnets. These losses have the potential to affect power and signal electronic devices and quench superconducing magnets. We have previously reported the total cross section measurement of U+U collisions at a center-of-mass energy of 192.8 GeV per nucleon-pair. Here we present the equivalent analysis for Au+Au collisions with the data available from a low-intensity store of RHIC Run in 2014.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW039
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TUPMY001	Very Low Emittance Muon Beam using Positron Beam on Target	positron, target, collider, electron	1536
	M. Antonelli, M.E. Biagini, M. Boscolo, A. Variola INFN/LNF, Frascati (Roma), Italy E. Bagli INFN-Ferrara, Ferrara, Italy G. Cavoto INFN-Roma, Roma, Italy P. Raimondi ESRF, Grenoble, France
	Muon beams are customarily obtained via K/π decays produced in proton interaction on target. In this paper we investigate the possibility to produce low emittance muon beams from electron-positron collisions at centre-of-mass energy just above the μ⁺{+}μ⁺{-} production threshold with maximal beam energy asymmetry, corresponding to a positron beam of about 45 GeV interacting on electrons on target. Performances on both amorphous and crystal target are presented, and the general scheme for the muon production will be given. We present the main features of this scheme with a first preliminary evaluation of the performances that could be achieved by a multi-TeV muon collider.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY001
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TUPMY002	APF IH-DTL Design for the Muon LINAC in the J-PARC Muon g-2/EDM Experiment	cavity, linac, DTL, acceleration	1539
	M. Otani, T. Mibe, M. Yoshida KEK, Tsukuba, Japan K. Hasegawa, Y. Kondo JAEA, Ibaraki-ken, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Iwata NIRS, Chiba-shi, Japan R. Kitamura University of Tokyo, Tokyo, Japan N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The muon linac for the J-PARC muon g-2/EDM experiment consists of RFQ (324 MHz), IH-DTL (324 MHz), DAW coupled cell linac (1.3 GHz), and disk loaded structure (1.3 GHz). Because muon has finite life time, the muons should be accelerated in a sufficiently short period. To realize fast acceleration, Alternative Phase Focusing (APF) scheme is adopted in IH-DTL in which the muons are accelerated from 0.34 MeV to about 4 MeV. In this poster, the design of the APF IH-DTL for muon acceleraiton with the computer calculation will be presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY002
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TUPMY004	The MICE Demonstration of Muon Ionization Cooling	lattice, betatron, simulation, experiment	1547
	J.-B. Lagrange, C. Hunt, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom V.C. Palladino INFN-Napoli, Napoli, Italy J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions up to several TeV at the Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate muon ionization cooling, the technique proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam traverses a material (the absorber) loosing energy, which is replaced using RF cavities. The combined effect is to reduce the transverse emittance of the beam (transverse cooling). The configuration of MICE required to deliver the demonstration of ionization cooling is being prepared in parallel to the execution of a programme designed to measure the cooling properties of liquid-hydrogen and lithium hydride. The design of the cooling-demonstration experiment will be presented together with a summary of the performance of each of its components and the cooling performance of the experiment. Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY004
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TUPMY006	MICE Step IV Optics without the M1 Coil in SSD	lattice, solenoid, simulation, scattering	1553
	A. Liu Fermilab, Batavia, Illinois, USA
	Funding: Fermi National Accelerator Laboratory The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the only technique that, given the short muon lifetime, can reduce the phase-space volume occupied by a muon beam quickly enough. MICE will demonstrate cooling in two steps. In the first one, Step IV, MICE will study the multiple Coulomb scattering in liquid hydrogen (LH2) and lithium hydride (LiH). A focus coil module will provide focussing on the absorber. The transverse emittance will be measured upstream and downstream of the absorber in two spectrometer solenoids (SS). Magnetic fields generated by two match coils in the SSs allow the beam to be matched into a flat-field regions in which the tracking detectors are installed. An incident in September 2015 rendered matching coil \#1 (M1D) of the downstream spectrometer inoperable. A new Step IV lattice without M1D and its optimization via a Genetic Algorithm (GA) will be described in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY006
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TUPMY010	Status of Mice Step IV	factory, experiment, optics, scattering	1562
	P.M. Hanlet IIT, Chicago, Illinois, USA
	Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE Muon beams of low emittance provide the basis for the intense, well characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling–the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam. MICE is being constructed in a series of Steps. The configuration currently in operation at the Rutherford Appleton Laboratory is optimised for the study the properties of liquid hydrogen and lithium hydride that affect cooling. The plans for data taking in the present configuration will be described together with a summary of the status of preparation of the experimental configuration by which MICE will demonstration the principle of ionization cooling. Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY010
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TUPMY011	Simulated Measurements of Cooling in Muon Ionization Cooling Experiment	lattice, solenoid, detector, electron	1565
	T.A. Mohayai IIT, Chicago, Illinois, USA C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom P. Snopok Fermilab, Batavia, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Cooled muon beams set the basis for the exploration of physics of flavour at a Neutrino Factory and for multi-TeV collisions at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) measures beam emittance before and after an ionization cooling cell and aims to demonstrate emittance reduction in muon beams. In the current MICE Step IV configuration, the MICE muon beam passes through low-Z absorber material for reducing its transverse emittance through ionization energy loss. Two scintillating fiber tracking detectors, housed in spectrometer solenoid modules upstream and downstream of the absorber are used for reconstructing position and momentum of individual muons for calculating transverse emittance reduction. However, due to existence of non-linear effects in beam optics, transverse emittance growth can be observed. Therefore, it is crucial to develop algorithms that are insensitive to this apparent emittance growth. We describe a different figure of merit for measuring muon cooling which is the direct measurement of the phase space density.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY011
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TUPMY012	Hybrid Methods for Simulation of Muon Ionization Cooling Channels	simulation, experiment, scattering, lattice	1568
	J.D. Kunz IIT, Chicago, Illinois, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work is supported by the U.S. Department of Energy. COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. New features are being developed for inclusion in COSY to follow the distribution of charged particles through matter. To study in detail some of the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the deterministic behavior of the particles in the accelerator channel, and Monte Carlo methods are used to model the stochastic processes intrinsic to liquid and solid absorbers. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed are expected to simplify the optimization of muon cooling channels which are usually very computationally demanding. Progress on the development of the required algorithms is reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY012
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TUPMY013	Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices	plasma, simulation, scattering, space-charge	1571
	J.S. Ellison IIT, Chicago, Illinois, USA P. Snopok Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Work supported by the U.S. Department of Energy. New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY013
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TUPMY030	Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes	electron, scattering, laser, experiment	1611
	E.A. Nanni, R.K. Li, C. Limborg, X. Shen, S.P. Weathersby SLAC, Menlo Park, California, USA W.S. Graves, R. Kirian, J. Spence, U. Weierstall Arizona State University, Tempe, USA
	A recently proposed method for the generation of relativistic electron beams with nanometer-scale current modulation requires diffracting relativistic electrons from a perfect crystal Si grating, accelerating the diffracted beam and imaging the crystal structure into the temporal dimension via emittance exchange. The relative intensity of the current modulation is limited by the ability to extinguish the transmitted beam via diffraction with a single-crystal Si membrane. In these preliminary experiments we will measure the extinction of the transmitted electron beam at zero scattering angle due to multiple Bragg scattering from a Si membrane with a uniform thickness of 340 nm at 2.35 MeV using the SLAC UED facility. The impact of beam divergence and charge density at the Si target will be quantified. The longevity of the Si membrane will also be investigated by monitoring the diffraction pattern as a function of time to observe the potential onset of damage to the crystal.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMY030
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TUPMY031	Estimation and Suppression of Aberrations in Emittance Exchange based Current Profile Shaping	collective-effects, space-charge, acceleration, FEL	1615
	G. Ha, M.-H. Cho, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea W. Gai, G. Ha, K.-J. Kim, J.G. Power ANL, Argonne, Illinois, USA
	The longitudinal current profile manipulation has been explored for many applications including THz radiation, FEL and advanced acceleration schemes. Especially, collinear dielectric wakefield accelerations require a microbunch shaping for a high transformer ratio. We have studied aberrations from the emittance exchange based current profile shaping to preserve the high transformer ratio. All second order aberration terms in the double dog-leg emittance exchange beam line are discovered. Aberration patterns from each aberration sources like second order terms, space-charge, and CSR and their effect on the transformer ratio are estimated analytically. These aberration sources and corresponding patterns are confirmed using a particle tracking code GPT. Simple methods to suppress each aberration will be presented too. All calculation in this work is done with a double dog-leg emittance exchange beam line.
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TUPMY044	Carbon and Mercury Target Systems for Muon Colliders and Neutrino Factories	target, proton, collider, factory	1641
	K.T. McDonald PU, Princeton, New Jersey, USA J.S. Berg, H.G. Kirk, D. Stratakis BNL, Upton, Long Island, New York, USA X.P. Ding UCLA, Los Angeles, California, USA
	Funding: Work supported in part by US DOE Contract NO. DE-AC02-98CH110886 A high-power target is required to convert a powerful MW-class proton beam into an intense muon source or neutrino source in support of physics at the intensity frontier. The first phase of a Muon Collider or Neutrino Factory program may use a 6.75-GeV proton driver with beam power of only 1 MW. At this lower power it is favorable to use a graphite target with beam and target tilted slightly to the axis of a 20-T pion-capture solenoid around the target. Using the MARS15 (2014) code, we optimized the geometric parameters of the beam and target to maximize particle production at low energies by an incoming proton beam with kinetic energy of 6.75 GeV impinging on this carbon target. We also studied beam-dump configurations to suppress the rate of undesirable high-energy secondary particles in the beam. For a possible upgrade to a proton beam of multi-MW power, we considered a free-flowing mercury jet.
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TUPOR009	Single Bunch Longitudinal Instability in the CERN SPS	impedance, simulation, flattop, synchrotron	1670
	A. Lasheen, T. Bohl, S. Hancock, T. Roggen, E.N. Shaposhnikova CERN, Geneva, Switzerland E. Radvilas Gediminas Technical University, Vilnius, Lithuania
	The longitudinal single bunch instability observed in the SPS leads to uncontrolled emittance blow-up and limits the quality of high intensity beams required for the High Luminosity LHC and AWAKE projects at CERN. The present SPS impedance model developed from a thorough survey of machine elements was used in macro-particle simulations (with the code BLonD) of the bunch behavior through the acceleration cycle. Comparison of simulations with measurements of the synchrotron frequency shift, performed on the SPS flat bottom to probe the impedance, show a reasonable agreement. During extensive experimental studies various beam and machine parameters (bunch intensity, longitudinal emittance, RF voltage, with single and double RF systems) were scanned in order to further benchmark the SPS impedance model with measurements and to better understand the mechanism behind the instability. It was found that the dependence of instability threshold on longitudinal emittance and beam energy has an unexpected non-monotonic behavior, leading to islands of (in)stability. The results of this study are presented and can be used to define possible parameter settings for the future CERN projects.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR009
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TUPOR010	Simulation of Instability at Transition Energy with a New Impedance Model for CERN PS	impedance, simulation, proton, synchrotron	1674
	N. Wang IHEP, Beijing, People's Republic of China S. Aumon, N. Biancacci, M. Migliorati, G. Sterbini, N. Wang CERN, Geneva, Switzerland M. Migliorati INFN-Roma1, Rome, Italy S. Persichelli University of Rome La Sapienza, Rome, Italy
	Instabilities driven by the transverse impedance are proven to be one of the limitations for the high intensity reach of the CERN PS. Since several years, fast single bunch vertical instability at transition energy has been observed with the high intensity bunch serving the neu-tron Time-of-Flight facility (n-ToF). In order to better understand the instability mechanism, a dedicated meas-urement campaign took place. The results were compared with macro-particle simulations with PyHEADTAIL based on the new impedance model developed for the PS. Instability threshold and growth rate for different longitu-dinal emittances and beam intensities were studied.
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TUPOR011	Study of Microwave Instability for SLS-2	impedance, vacuum, storage-ring, simulation	1678
	H.S. Xu, P. Craievich, M.M. Dehler, L. Stingelin PSI, Villigen PSI, Switzerland
	An ultra-low emittance electron storage ring is under development for the Upgrade of Swiss Light Source (SLS-2). An antechamber scheme consisting of round beam channel with 10 mm inner radius is considered to accommodate the required strong quadrupole and sextupole magnets, achieve the ultra-high vacuum, and absorb the undesired synchrotron radiation. However, the small size of vacuum chamber increases the susceptibility of the beam to the impedance induced collective instabilities. We will present the preliminary study of the microwave instability for SLS-2 storage ring considering the longitudinal Resistive-Wall (RW) impedance due to three different options for the beam chamber. The microwave instability thresholds are calculated under the conditions of two possible RF frequencies (100 MHz and 500 MHz) and three different materials (aluminum, copper, and stainless steel). The influences of third-harmonic cavities are also studied.
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TUPOR017	Beam-beam Simulation of Crab Cavity with Frequence Dependent Noise for LHC Upgrade	luminosity, cavity, simulation, feedback	1691
	J. Qiang LBNL, Berkeley, California, USA G. Arduini, Y. Papaphilippou, T. Pieloni CERN, Geneva, Switzerland J. Barranco EPFL, Lausanne, Switzerland
	High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the frequence-dependent crab cavity noise on the beam luminosity lifetime using strong-strong beam-beam simulations.
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TUPOR019	RF Injector Beam Dynamics Optimization and Injected Beam Energy Constraints for LCLS-II	cavity, laser, electron, gun	1699
	C.E. Mitchell, H.J. Qian, J. Qiang, F. Sannibale, M. Venturini LBNL, Berkeley, California, USA P. Emma, T.O. Raubenheimer, J.F. Schmerge, F. Zhou SLAC, Menlo Park, California, USA
	Funding: Work supported by the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231. LCLS-II is a proposed high-repetition rate (>1 MHz) Free Electron Laser (FEL) X-ray light source, based on a CW, superconducting linac, to be built at SLAC National Accelerator Laboratory. The injector technology is based on a high-repetition rate RF photoinjector gun developed as part of the Advanced Photoinjector Experiment (APEX) at Lawrence Berkeley National Laboratory. Exploration of the injector design settings is performed using a multiobjective genetic optimizer to optimize the beam quality at the injector exit (~100 MeV). In this paper, we describe the current status of LCLS-II injector design optimization, with a focus on the sensitivity of the optimized solutions to the beam energy at the injector exit, which is constrained by the requirements of the downstream laser heater system.
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TUPOR021	Incoherent Vertical Emittance Growth from Electron Cloud at CesrTA	simulation, dipole, electron, positron	1707
	S. Poprocki, J.A. Crittenden, S.N. Hearth, J.D. Perrin, D. L. Rubin, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by the US National Science Foundation PHY-1416318, PHY-0734867, and PHY-1002467, and the U.S. Department of Energy DE-FC02-08ER41538 We report on measurements of electron cloud (EC) induced tune shifts and emittance growth at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) with comparison to tracking simulation predictions. The simulations are based on a weak-strong model of the interaction of the positron beam (weak) with the electron cloud (strong), using electric fields computed with established EC buildup simulation codes (ECLOUD). Experiments were performed with 2.1 GeV positrons in a 30 bunch train with 14 ns bunch spacing and 9 mm bunch length, plus a witness bunch at varying distance from the train to probe the cloud as it decays. Measurements of the horizontal and vertical coherent tune shifts and horizontal and vertical bunch size were obtained for a range of train and witness bunch currents, and compared to simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR021
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TUPOW003	High Average RF Power Tests With 2 RF Vacuum Windows at PITZ	gun, operation, vacuum, Windows	1744
	Y. Renier, G. Asova, M. A. Bakr, P. Boonpornprasert, J.D. Good, M. Groß, C. Hernandez-Garcia, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, O. Lishilin, G. Loisch, D. Malyutin, D. Melkumyan, A. Oppelt, M. Otevřel, G. Pathak, T. Rublack, I.V. Rybakov, F. Stephan, G. Vashchenko, Q.T. Zhao DESY Zeuthen, Zeuthen, Germany M. Bousonville, S. Choroba, S. Lederer DESY, Hamburg, Germany
	The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was built with the aim to develop and characterize electron sources for future usage at FLASH and at the European XFEL. Recently, the main focus at PITZ has been the study of gun reliability and photoinjector performance at high average power. The goal is to get stable and reliable operation with 6.4 MW peak power in the gun at 650 us RF pulse length and 10 Hz repetition rate. To achieve this, a new RF feed system with two RF windows was installed at PITZ in 2014. During this test, the old gun 4.2 with a modified back-plane design for better cathode contact has been used. In this contribution the results of the RF conditioning of gun 4.2 with a detailed interlock analysis will be reported as well as results from recent electron beam characterization.
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TUPOW006	Six-dimensional Phase-space Rotation and its Applications	FEL, cathode, simulation, electron	1754
	M. Kuriki, K. Negishi HU/AdSM, Higashi-Hiroshima, Japan H. Hayano, R. Kato, K. Ohmi, M. Satoh, Y. Seimiya, J. Urakawa KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Funding: This work is partly supported by Grant-in-Aid for Scientific Research by MEXT, Japan (KAKENHI) 25390126. Recent progress on the accelerator science requires optimized phase space distributions of the beam for each applications. A classical approach to satisfy the requirements is minimizing the beam emittance with a bunch charge as much as possible. This classical approach is not efficient and not compatible to the beam dynamics nature. 6D phase-space rotation, e.g. z-x and x-y, gives a way to optimize the phase space distribution for various applications. In this article, we discus possible applications of the 6D phase space rotation. The x-y rotation generates the high aspect ratio beam for linear colliders directly without DR (Damping Ring). Combination of bunch clipping with a mechanical slit and x-z rotation can generate micro-bunch structure which is applicable for FEL enhancement and drive beam for dielectric acceleration. We present our theoretical and simulation study on these applications.
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TUPOW011	Profile Measurements of Bremsstrahlung Gamma-Rays from Tungsten Plates for Radioactive Isotope Production via Photonuclear Reaction using a 60 MeV Electron Linac	electron, quadrupole, detector, simulation	1766
	K. Takahashi, H. Hama, F. Hinode, S. Kashiwagi, H. Kikunaga, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, T. Suda, C. Tokoku, K. Tsukada Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Radioactive isotopes have been produced via photo-nuclear reaction using a 60 MeV high-power electron linac for research fields of nuclear chemistry and radioac-tive analysis at Research Center for Electron Photon Science (ELPH), Tohoku University. The electron beam with an average current more than 100 μA is transported to an electron-bremsstrahlung gamma-ray converter of 2 mm thickness platinum or tungsten plate at the irradiation station. A target of 10 mm diameter is placed 3 cm behind a converter. It is enclosed with a quartz glass in the water cooling system and is irradiated for photonuclear reaction. Since the correlation between the spatial profile of bremsstrahlung gamma-rays at the target position and accelerator parameters is of our primary interest, nickel thin films are irradiated and the profiles of bremsstrahlung gamma-rays are measured by intensity distribution measurements of 57Ni radioactivity using the phosphorus imaging plate. In the meantime, the beam emittance and Twiss parameters are measured.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW011
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TUPOW026	Optimization of Electron Beam Properties for Generation of Coherent THz Undulator Radiation at PBP-CMU Linac Laboratory	radiation, undulator, electron, linac	1803
	N. Chaisueb, S. Rimjaem, J. Saisut, C. Thongbai Chiang Mai University, Chiang Mai, Thailand

Paper

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MOYAA01

Commissioning of the MAX IV Light Source

storage-ring, injection, lattice, vacuum

11

M. Eriksson, E. Al-Dmour, Å. Andersson, M.A.G. Johansson, S.C. Leemann, L. Malmgren, P.F. Tavares, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

This presentation reports on the beam commissioning status of MAX IV, experience gained and lessons learned, as well as future plans.

Slides MOYAA01 [6.682 MB]

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MOZA02

Design and Optimization Strategies of Nonlinear Dynamics in Diffraction-limited Synchrotron Light Sources

sextupole, lattice, optics, resonance

33

R. Bartolini
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

This talk introduces the most recent achievements in the control of nonlinear dynamics in electron synchrotron light sources, with special attention to diffraction limited storage rings. Guidelines for the design and optimization of the magnetic lattice are reviewed and discussed.

Slides MOZA02 [4.952 MB]

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MOPMB011

ROSE, Measuring the Full 4D Transverse Beam Matrix of Ion Beams

ion, vacuum, coupling, detector

98

M.T. Maier, X. Du, P. Gerhard, L. Groening, S. Mickat, H. Vormann, C. Xiao
GSI, Darmstadt, Germany

A ROtating System for Emittance measurements ROSE, to measure the full 4 dimensional transverse beam matrix of an ion beam has been developed and commissioned. Different ion beams behind the HLI at GSI have been used in two commissioning beam times. All technical aspects of ROSE have been tested, ROSE has been benchmarked against existing emittance scanners for horizontal and vertical projections, and the method, hard-, and software to measure the 4D beam matrix has been upgraded, refined, and successfully commissioned. The inter plane correlations of the HLI beam have been measured, yet as no significant initial correlations were found to be present, controlled coupling of the beam by using a skew triplet has been applied and confirmed with ROSE. The next step is to use ROSE to measure and remove the known inter plane correlations of a uranium beam before SIS18 injection.

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MOPMB019

Quadrupole Scan Emittance Measurements for the ELI-NP Compton Gamma Source

electron, quadrupole, linac, laser

126

A.R. Rossi, A. Bacci, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
E. Chiadroni, C. Vaccarezza, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Curatolo, I. Drebot
Universita' degli Studi di Milano e INFN, Milano, Italy
A. Giribono, A. Mostacci
University of Rome La Sapienza, Rome, Italy
V. Petrillo, M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

The high brightness electron LINAC of the Compton Gamma Source at the ELI Nuclear Physics facility in Romania is accelerating a train of 32 bunches with a nominal charge of 250 pC and nominal spacing of 16 ns. To achieve the design gamma flux, all the bunches along the train must have the designed Twiss parameters. Beam sizes are measured with optical transition radiation monitors, allowing a quadrupole scan for Twiss parameters measurements. Since focusing the whole bunch train on the screen may lead to permanent screen damage, we investigated non-conventional scans such as scans around a maximum of the beam size or scans with a controlled minimum spot size. This paper discusses the implementation issues of such a technique in the actual machine layout.

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MOPMB022

Conceptual Design for SR Monitor in the FCC Beam Emittance (Size) Diagnostic

extraction, diagnostics, vacuum, brightness

133

T.M. Mitsuhashi, K. Oide
KEK, Ibaraki, Japan
F. Zimmermann
CERN, Geneva, Switzerland

A conceptual design for emittance diagnostics through a beam size measurement using the synchrotron radiation (SR) is studied for the FCC. For the FCC-ee, a X-ray interferometer is propose to measure a nano-radian order vertical beam size. Also conceptual design of SR monitor is studied for FCC-hh. In the FCC-hh, visible SR will emitted from bending magnet in the energy range from the injection (3TeV) to top energy (50TeV). Hard X-ray SR will only available in the energy upper than 30TeV. The various instrumentations using the visible SR is usable for all energy range. Around the top energy, the X-ray pinhole camera will convenient for beam diagnostics of emittance through the beam size measurement.

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MOPMB028

Development of Beam Diagnostic System for the SPring-8 Upgrade

diagnostics, radiation, beam-diagnostic, photon

149

H. Maesaka, T. Ohshima, Y. Otake
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Dewa, T. Fujita, K. Kobayashi, M. Masaki, S. Matsubara, T. Nakamura, S. Sasaki, S. Takano
JASRI/SPring-8, Hyogo-ken, Japan

The goal of the beam diagnostic system for the SPring-8 upgrade is to deliver brilliant X-rays enabled by the new low-emittance ring to experimental stations with ultimate stability. Developments of accurate electron and photon beam position monitors (EBPM and XBPM, respectively) with both short and long-term stability are the most critical. The EBPM sensitivity is also crucial for low-current beam commissioning to accomplish the first beam storage in the ring. We designed a button electrode to obtain sufficiently high-intensity signals while suppressing high-Q trapped modes leading to impedance and heating issues. We also designed a precise EBPM block and a rigid support to achieve mechanical accuracy and stability. Another challenge is the development of a reliable and stable XBPM, which should be an accurate reference for an orbit feedback without any photon-energy dependences. A significant improvement of a blade-type XBPM or an invention of a novel XBPM detecting the core of an intense X-ray beam are necessary. The other diagnostic instrumentations can be utilized for the new ring with minor improvements.

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MOPMB034

Design and Application of Double-slit Emittance Meter for C-ADS Proton Beams

rfq, proton, background, instrumentation

164

L. Yu, Y.F. Sui, J.X. Zhao, D.C. Zhu
IHEP, Beijing, People's Republic of China

To reduce the beam loss in the high current linac, beam transverse emittance is a key value which has to be characterized. At Institute of High Energy Physics (IHEP) in Beijing the C-ADS project has started beam commissioning. A newly developed double-slit emittance meter (DEM) for pulsed proton beam from the (RFQ) has been installed in the beam line. In this paper principal of operation, instrumentation and programming of emittance meter are discussed. The emittance measurement has been carried out with the newly developed DEM at a beam energy of 3.2 MeV and a beam current of 10 mA. Typical rms emittance for x and y direction are measured to be 0.1303 and 0.1347 π mm mrad，which are well below the design standard of the RFQ.

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MOPMB040

Design of the Beam Diagnostics System for a New IR-FEL Facility at NSRL

diagnostics, FEL, laser, cavity

181

J.H. Wei, X.Y. Liu, P. Lu, B.G. Sun, L.L. Tang, F.F. Wu, Y.L. Yang, T.Y. Zhou, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (21327901, 11105141, 11575181)
A new IR-FEL has been commissioned at NSRL. This facility provides a final electron energy from 20 to 70 MeV, beam bunch with a macro-pulse length of 5~10 μs and a general micro-pulse repetition rate of 238 MHz, pulsed radiation with up to 100 mJ at about 0.3%~3% FWHM bandwidth. So a diagnostics system is necessary to monitor the performance of the bunch and the character of the FEL radiation, such as the beam position and profile, emittance, energy spread, laser intensity, etc. The beam diagnostics system mainly consists of Flags, a diagnostics beam line, BPMs, pop-in monitors and a FEL monitor system. This paper introduces the construction of this diagnostics system.
Corresponding author: ylyang@ustc.edu.cn

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MOPMB052

On-axis Injection using a Sin Wave RF Kicker

kicker, injection, storage-ring, lattice

211

B.C. Jiang, Y.B. Leng, S.Q. Tian, L.Y. Yu, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

On-axis injection is one of the critical issues for an ul-tra-low emittance storage ring which holds a rather small dynamic aperture. In order to reduce the challenges of the fast pulsed kicker design, a sin wave RF kicker is studied which is suitable for longitudinal on-axis injection. Since the injected bunch is longitudinally apart from the stored bunches, the location of the stored bunches can be at the π knot of the sin wave, while the injected bunches are launched at a phase around π/2+n·π. At this situation the injected bunches will receive a transverse kick, however the store bunches are almost un-affected.

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MOPMB060

Upgrade of the LHC Schottky Monitor, Operational Experience and First Results

pick-up, proton, ion, injection

226

M. Betz, O.R. Jones, T. Lefèvre, M. Wendt
CERN, Geneva, Switzerland

The LHC Schottky system allows the measurement of beam parameters such as tune and chromaticity in an entirely non-invasive way by extracting information from the statistical fluctuations in the incoherent motion of particles. The system was commissioned in 2011 and provided satisfactory beam-parameter measurements during LHC run 1 for lead-ions. However, for protons its usability was substantially limited due to strong interfering signals originating from the coherent motion of the particle bunch. The system has recently been upgraded with optimized travelling-wave pick-ups and an improved 4.8~GHz microwave signal path, with the front-end and the triple down-mixing chain optimized to reduce coherent signals. Design and operational aspects for the complete system are shown and the results from measurements with LHC beams in Run II are presented and discussed.

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MOPMR012

Studies of Buffer Gas Cooling of Ion Beams in an RFQ Cooler and Their Transport to the EBIS Charge Breeder

ion, rfq, simulation, radio-frequency

248

K.H. Yoo, M. Chung
UNIST, Ulsan, Republic of Korea
H.J. Son
IBS, Daejeon, Republic of Korea

In rare isotope accelerator facilities, an RFQ cooler is often used to manipulate ions. The RFQ cooler is a de-vice to effectively cool and confine ions in gaseous envi-ronment. The RFQ cooler provides a radial electric force to the beam by applying RF voltages to the quadrupole electrode structures, and axial force by applying different DC voltages to the segmented electrodes. The ions are trapped inside the potential well of the RFQ cooler formed by the DC fields, so that they have more colli-sions with the buffer gas. Several important parameters such as transverse emittance can be improved when ion beams are extracted from the RFQ cooler. In order to design an efficient RFQ cooler, which can properly match the ion beams into the EBIS charge breeder, it is essential to analyze evolutions of the transverse emittance and transmission efficiency through the RFQ cooler. Moreo-ver, to minimize emittance growth and maximize trans-mission efficiency, the beam transport line to the EBIS charge breeder needs to be optimized. In this work, we study the methods to apply the mechanism of buffer gas cooling in RFQ cooler to G4beamline and the beam transport line to EBIS charge breeder to TRACK.

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MOPMR022

Beam-based Alignment of CLIC Accelerating Structures Utilizing Their Octupole Component

octupole, collider, linear-collider, linac

280

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Alignment of the accelerating structures is essential for emittance preservation in long linear accelerators such as the Compact Linear Collider (CLIC). The prototype structures for CLIC have four radial waveguides connected to each cell for damping wakefields and this four-fold symmetry is responsible for an octupole component of the radio-frequency fields, phase-shifted 90 degrees with respect to the accelerating mode. The octupole field causes a nonlinear dependence of the transverse beam deflection with respect to the position within the accelerating structure. By transversely moving the beam with two upstream steering magnets, and observing the deflection with beam position monitors or screens, the electromagnetic center of the structure can be found. We discuss the applicability of this method for aligning the beam in the accelerating structures.

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MOPMR025

Beam Size Estimation from Luminosity Scans at the LHC During 2015 Proton Physics Operation

luminosity, proton, operation, experiment

290

M. Hostettler, G. Papotti
CERN, Geneva, Switzerland
M. Hostettler
LHEP, Bern, Switzerland

As a complementary method for measuring the beam size for high-intensity beams at 6.5 TeV flat-top energy, beam separation scans were done regularly at the CERN Large Hadron Collider (LHC) during 2015 proton physics operation. The luminosities measured by the CMS experiment during the scans were used to derive the convoluted beam size and orbit offset bunch-by-bunch. This contribution will elaborate on the method used to derive plane-by-plane, bunch-by-bunch emittances from the scan data, including uncertainties and corrections. The measurements are then compared to beam size estimations from absolute luminosity, synchrotron light telescopes, and wire scanners. In particular, the evolution of the emittance over the course of several hours in collisions is studied and bunch-by-bunch differences are highlighted.

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MOPMR026

Beam Instrumentation Performance during Commissioning of CERN's Linac-4 to 50 MeV and 100 MeV

laser, linac, DTL, detector

293

U. Raich, T. Hofmann, F. Roncarolo
CERN, Geneva, Switzerland

Linac-4, a 140 MeV H-linear accelerator is designed to replace the aging 50 MeV proton Linac. It will consist of an H-source and 45 keV LEBT, an RFQ and 3 MeV MEBT with a chopper, 3 drift tube linac (DTL) tanks accelerating the beam to 12, 30 and 50 Mev, cavity coupled structures (CCDTL) accelerating it to 100 MeV and a pi mode structure bringing it to its design energy of 160 MeV. This paper reports on the commissioning of the DTL and CCDTL with 2 dedicated temporary measurement lines, the first one adapted to the 12 MeV beam while the second one is dedicated to characterize the 50 MeV and the 100 MeV beams. The beam diagnostic devices used in these lines is described as well as results obtained.

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MOPMR027

Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements

detector, vacuum, luminosity, real-time

296

M.N. Rihl, A. Alexopoulos, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, V. Salustino Guimaraes, B. Salvant, R. Veness, S. Vlachos
CERN, Geneva, Switzerland
A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, P. Hopchev, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu
EPFL, Lausanne, Switzerland
R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig
RWTH, Aachen, Germany

Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed**, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed.
* LHCb collaboration, Journal of Instrumentation, 9, P12005
** P. Hopchev in Proc. of IPAC 2014, June 15-20, 2014, Dresden Germany

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MOPMR028

Emittance Characterisation of High Brightness Beams in the CERN PS

proton, brightness, synchrotron, extraction

299

G. Sterbini, J.F. Comblin, V. Forte, A. Guerrero, E. Piselli
CERN, Geneva, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France

Measurements in the CERN Proton Synchrotron showed that achieving the required accuracy for the emittance characterisation of high brightness beams is challenging. Some of the present limits can be related to systematic errors in the wire scanner calibration or, for the horizontal emittance determination, in the assumptions adopted while deconvoluting the contribution of the longitudinal plane from the measured transverse profile. We present in this paper the results of a beam-based test of the wire scanner calibration and of a general numerical deconvolution algorithm to compute the betatronic profile starting from the measured ones. In addition to the bunch train average emittance, a bunch-by-bunch transverse emittance measurement would increase the potential to understand, optimise and monitor the beam performance. In 2015 the first PS bunch-by-bunch measurement chain was setup. The results are reported and discussed.

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MOPMR039

Review of Emittance Diagnostics for Space Charge Dominated Beams for AWAKE e^- Injector

space-charge, quadrupole, focusing, radiation

337

O. Mete Apsimon, G.X. Xia
UMAN, Manchester, United Kingdom
S. Döbert
CERN, Geneva, Switzerland
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This work is supported by the Cockcroft Institute Core Grant and STFC.
For a low energy, high intensity beam, total beam emittance is dominated by defocusing space charge force. This is most commonly observed in photo-injectors. In this low energy regime, emittance measurement techniques such as quadrupole scans fail as they consider the beam size only depends on optical functions. The pepper-pot method is used for 2D emittance measurements in a single shot manner. In order to measure the beam emittance in space charge dominated regime by quadrupole scans, space charge term should be carefully incorporated into the transfer matrices. On the other hand, methods such as divergence interferometry via optical transition radiation (OTRI), phase space tomography using 1D projections of quadrupole scans can be suitably applied for such conditions. In this paper, the design of a versatile pepper-pot system for AWAKE experiment at CERN is presented for a wide range of bunch charges from 0.1 to 1nC where the space charge force increases significantly. In addition, other aforementioned methods and respective algorithms are introduced as alternative methods.

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MOPMR048

Emittance Measurements and Operation Optimization for ECR Ion Sources

ion, ion-source, ECR, cyclotron

361

V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
O. Kamigaito, T. Nagatomo, T. Nakagawa, V. Tzoganis
RIKEN Nishina Center, Wako, Japan
V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: RIKEN IPA scheme and Cockcroft Institute Core Grant
Electron Cyclotron Resonance (ECR) ion sources supply a broad range of ions for post acceleration in cyclotrons. Here, an effort to improve the beam transfer from RIKEN's 18 GHz ECR ion source to the Low Energy Beam Transfer (LEBT) line and an optimization of the performance of the ion source is presented. Simulation studies have shown that less than 20% of the beam is currently transferred. The first goal is to measure the transverse beam emittance in real time. The emittance monitor designed and fabricated for this purpose utilizes a pepper pot plate followed by a transparent scintillator and a CMOS camera for image capture. The second goal is to find the optimal operating point of the ion source by sweeping parameters such as RF power, vacuum pressure, extraction electrode position and voltage. To this extent, modifications of the ion source took place, as well as a measurement of the magnetic field inside the ion source. In this contribution the results of the emittance and other operating parameters measurements, as well as the design details of the emittance monitor are presented

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MOPMW029

Analysis of Transverse Field Induced by Curved Beryllium Window in Muon Ionization Cooling Cavity

cavity, Windows, acceleration, focusing

457

T.H. Luo, D. Li
LBNL, Berkeley, California, USA

The beryllium windows are used in muon ionization cooling cavity to increase the cavity shunt impedance. The windows are curved for predictable thermal deformation. This curvature also introduces transverse field, which will affect the transverse beam emittance. In this paper, we will analyze this transverse field and evaluate its effect on the emittance cooling.

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MOPMY001

Beam Dynamics Analysis for the Ultra-fast Kicker in Circular Cooler Ring of JLEIC

kicker, electron, cavity, recirculation

510

Y.L. Huang
IMP/CAS, Lanzhou, People's Republic of China
R.A. Rimmer, H. Wang, S. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
An ultra-fast kicker system consist of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency, thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mA - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesis such a kicker waveform will be discussed with the comparison of beam dynamics tracking in Elegant.

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MOPOR004

Recent Progress of 1-MW Beam Tuning in the J-PARC 3-GeV RCS

resonance, injection, scattering, power-supply

592

H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV RCS started 1 MW beam test from October 2014, and successfully achieved a 1 MW beam acceleration in January 2015. Since then, a large fraction of our effort has been focused on reducing and managing beam losses. This paper presents the recent progress of 1 MW beam tuning, especially focusing on our approaches to beam loss issues, such as space-charge induced beam loss and foil scattering beam loss during charge-exchange injection, etc.

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MOPOR017

First Year Performance of the TPS Booster Ring

booster, synchrotron, linac, storage-ring

634

H.-J. Tsai, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.Y. Liao, Y.-C. Liu, G.-H. Luo, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a 3-GeV low- emittance light source of circumference 518.4 m. The booster ring is in the same tunnel with the storage ring; its circumference at 496.8 m makes it the largest booster ring in operation in existing light sources. Since the successful commissioning at the end of 2014, the TPS booster ring has been optimized in performance for routine operation. In this paper, we present the system upgrade and the improvement of the ramping procedure to increase the capture and ramping efficiency of the beam charge, the characterization of the optics, etc.

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MOPOR019

Beta Function Measurement and Resonances Induced by Space Charge Force and Lattice Magnets

resonance, space-charge, lattice, simulation

641

K. Ohmi, K.G. Sonnad
KEK, Ibaraki, Japan

J-PARC MR has been operated at tune (ν_x,ν_y)=(22.40,20.75). A new operating point around (21.4,21.4) has been proposed by simulation studies on space charge effect since 2013. Machine experiments at the operating point has been performed since 2014 and many encouraging results are being obtained. We discuss why new operating point is better than present one from view point of space charge effects.

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MOPOR021

Space Charge Studies with High Intensity Single Bunch Beams in the CERN SPS

injection, brightness, resonance, space-charge

644

H. Bartosik, F. Schmidt
CERN, Geneva, Switzerland
A. Oeftiger
EPFL, Lausanne, Switzerland
M. Titze
HZB, Berlin, Germany

In order to reach the target beam parameters of the LHC injectors upgrade (LIU) project the beam degradation due to losses and emittance growth on the long injection plateau of the SPS needs to be minimized. A detailed study of the dependence of losses, transverse emittance blow-up and transverse beam tail creation as function of the working point is presented here for a high brightness single bunch beam with a vertical space charge tune spread of about 0.2 on the 26 GeV injection plateau. The beam behaviour close to important betatron resonances is characterised and a region in the tune diagram with minimal beam degradation is identified. Implications about the performance for LIU beams are discussed.

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MOPOR022

Beam Dynamics Observations of the 2015 High Intensity Scrubbing Runs at the Cern Sps

electron, operation, octupole, injection

648

H. Bartosik, G. Iadarola, K.S.B. Li, L. Mether, A. Romano, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland

Beam quality degradation caused by e-cloud effects has been identified as one of the main performance limitations for high intensity LHC beams with 25 ns bunch spacing in the SPS. In view of the beam parameters targeted with the LHC injectors upgrade (LIU) project, about two weeks of SPS machine time in 2015 were devoted to dedicated scrubbing runs with high intensity LHC 25 ns and dedicated 'doublet' beams in order to study the achievable reduction of e-cloud effects and quantify the consequent beam performance improvements. This paper describes the main observations concerning the coherent instabilities and beam dynamics limitations encountered as well as a detailed characterisation of the performance reach with the highest beam intensity presently available from the pre-injectors.

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MOPOR023

Flat Bunches with a Hollow Distribution for Space Charge Mitigation

space-charge, synchrotron, resonance, injection

652

A. Oeftiger, H. Bartosik, A. Findlay, S. Hancock, G. Rumolo
CERN, Geneva, Switzerland
A. Oeftiger
EPFL, Lausanne, Switzerland

Funding: CERN, Doctoral Studentship EPFL, Doctorate
Longitudinally hollow bunches provide one means to mitigate the impact of transverse space charge. The hollow distributions are created via dipolar parametric excitation during acceleration in CERN's Proton Synchrotron Booster. We present simulation work and beam measurements. Particular emphasis is given to the alleviation of space charge effects on the long injection plateau of the downstream Proton Synchrotron machine, which is the main goal of this study.

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MOPOR024

Evolution of High Intensity Beams in the CERN PS Booster after H⁻ Injection and Phase Space Painting

injection, space-charge, booster, lattice

656

M. Cieslak-Kowalska, J.L. Abelleira, E. Benedetto, C. Bracco
CERN, Geneva, Switzerland

With the LHC Injector Upgrade (LIU) project, the injection energy of PS Booster (PSB) ' first circular accelerator in the LHC injector chain ' will be raised from 50 MeV to 160 MeV and the present multiturn injection will be upgraded to H⁻ injection with transverse and longitudinal painting. In the scope of this project, it is planned to double the beam intensities, profiting from the fact that the βγ2 factor will be two times larger (0.35 at 50 MeV and 0.71 at 160 MeV), so the resulting tune spread driven by a direct space charge should remain similar. This paper describes the feasibility to double the intensity of high intensity and large emittance beams, looking into the evolution under space charge and taking into account losses constrains in the ring and in the extraction lines.

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MOPOR025

3D Emittances Tailoring Techniques and Optimization with Space Charge for the Future CERN PS Booster Operations with Linac4

injection, coupling, simulation, linac

660

V. Forte, J.L. Abelleira, E. Benedetto, C. Bracco, M. Cieslak-Kowalska, G.P. Di Giovanni
CERN, Geneva, Switzerland

In the frame of the LIU (LHC Injectors Upgrade) project, the CERN PS Booster is going to be renovated to host a new H⁻ charge-exchange injection from the Linac4. One important feature of the new injection scheme is the possibility to tailor a wide range of 3D emittances for CERN's different users in an intensity span in the order of 5·10⁹ to 1.6·10¹³ protons per PSB ring. This paper gives an overview of 3D multi-turn injection techniques, focusing on the future LHC beams, which aim at reaching high brightness, and on highest intensity beams (ISOLDE), where losses are the main concern. Complete RF capture simulations and transverse injection maps, including space charge effects, are presented and also intended to be used during the commissioning with Linac4.

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MOPOR032

Using of the MENT Method for Reconstruction of 2D Particle Distributions in IFMIF Accelerators

linac, SRF, simulation, HOM

668

P.A.P. Nghiem, N. Chauvin, L. Ducrot, M. Valette
CEA/DSM/IRFU, France

Beam particles are characterized by their coordinates in real spaces or phase spaces that are at least two-dimensional. It is often necessary to reconstruct such a 2D-distribution from the knowledge of only its projections on some axes, either for making use of tomography measurement results or for setting up an input beam for transport simulations. In this article, the use of the MENT (Maximum Entropy) reconstruction method is reported for the IFMIF accelerators where high intensity beam distributions are far from Gaussian ones.

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MOPOR035

Space Charge Neutralization Studies with H⁻ Beam in Low Energy Beam Transport Test Stand

space-charge, ion, ion-source, rfq

677

S. Artikova
Private Address, Tsukuba, Japan
K. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Shibata, A. Takagi
KEK, Tokai, Ibaraki, Japan

J-PARC is intensity-upgraded up to pulse current of 50 mA of H⁻ beam. Two-solenoid based LEBT test stand is being built to support the operation of J-PARC linac. It imitates the actual LEBT of linac, yet contains the diagnostics chamber composed of horizontal and vertical beam emittance-meters and Faraday-cup for the current measurement. Vacuum composition of LEBT is predominantly H2 gas. The pressure inside the LEBT can be varied by the differential pumps allowing us to study the beam phase space evolution under space charge effects. The measurements of the beam phase space emittance were made as a function of the residual gas pressure. This paper presents the results and discussion on beam space charge neutralization and its effect on the beam phase space emittance.

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MOPOR038

Implications of Resonantly Driven Higher Order Modes on the ESS Beam

HOM, cavity, simulation, linac

683

A. Farricker, R.M. Jones, N.Y. Joshi
UMAN, Manchester, United Kingdom
S. Molloy
ESS, Lund, Sweden

The European Spallation Source (ESS) in Lund, Sweden, will be a facility for fundamental physics studies of atomic structure using a spallation source of unparalleled brightness. To achieve this end, a 2.86 ms long pulsed proton beam will be accelerated up to a final energy of 2 GeV using three suites of superconducting cavities. If a Higher Order Mode (HOM) lies on a harmonic of the bunch frequency the HOM will be resonantly driven. This will dilute the beam quality significantly. Errors in fabricating these cavities are inevitable, and this sets a tolerance on how close the HOM can be within a harmonic of the bunch frequency. The baseline design for ESS requires HOMs to be at least 5 MHz from a machine line. Here we provide details of several finite element electromagnetic simulations on the HOMS anticipated in these ESS cavities. We analyse their impact on the beam emittance using a drift-kick-drift model with the potential for relaxed tolerances.

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MOPOW012

Transverse Coherence and Fundamental Limitation on the Pointing Stability of X-ray FELs

FEL, radiation, electron, photon

735

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

The radiation from SASE FEL has always limited value of the degree of transverse coherence*. When transverse size of the electron beam significantly exceeds diffraction limit, the mode competition effect does not provide the selection of the ground mode, and spatial coherence degrades due to contribution of the higher azimuthal modes. An important consequence of this effect are fluctuations of the spot size and pointing stability of the photon beam**. These fluctuations are fundamental and originate from the shot noise in the electron beam. The effect of pointing instability becomes more pronouncing for shorter wavelengths. We analyze in detail the case of optimized SASE FEL* and derive universal dependencies applicable to all operating and planned x-ray FELs. We show that the hard x-ray FELs driven by low energy beams may exhibit poor spatial coherence and bad pointing stability.
* E.L. Saldin, E.A. Schneidmiller and M.V. Yurkov, Opt. Commun. 281(2008)1179.
** E.A. Schneidmiller and M.V. Yurkov, Proc. FEL2015 Conference, Daejeon, Korea, 2015, TUP021.

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MOPOW036

Design Optimization of an X-band based FEL

linac, FEL, simulation, gun

793

A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
Z. Nergiz
Nigde University, Nigde, Turkey

A design effort for a new generation of compact, cost-effective, power-efficient FEL facilities, based on X-band technology, has been launched. High-frequency X-band acceleration implies strong wakefields, tight alignment and mechanical tolerances, and challenging stability issues. In this paper a design is proposed for the injector and the linacs, including the two bunch compressors. RF gun and injector simulations have been performed, successfully meeting the stringent requirements in terms of minimum projected emittance, sliced emittance and minimum bunch length. In the design of the linac and bunch compressors wakefield effects and misalignment have been taken into account. Start-to-end tracking simulations through the optimized lattice are presented and discussed.

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MOPOW050

Study of Lower Horizontal Emittance Optics in the Present Soleil Storage Ring

quadrupole, lattice, optics, dynamic-aperture

827

H.C. Chao, P. Brunelle, A. Nadji, L.S. Nadolski, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

With the aim of delivering a lower horizontal emittance beam to the users of the present SOLEIL ring, a systematic lattice study is carried out. The goal is to discover feasible optics solutions having the horizontal emittance notably lower than the present value of 3.9 nm rad, while fulfilling all the physical requirements and without changing the current magnet structure in the lattice. The strategy adopted is a cell-wise optimization of the linear lattices in the two types of double-bend cells that constitute the SOLEIL ring. In the second step they are concatenated via finer matching. A global scan of the 5 quadrupole families for the search of stable solutions is performed. The statistical properties are given. One can easily select possible solutions without matching. For the second type of cell having 10 quadrupole families, another scan of quadrupoles and a matching using a quadrupole triplet are applied for linear optics characteristics. Finally, the nonlinear optimization is performed with modern nonlinear optimization algorithms.

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MOPOW051

High Level Control Command for ThomX Transfer Line

linac, quadrupole, optics, TANGO

830

C. Bruni, I. Chaikovska, S. Chancé, N. Delerue, A.R. Gamelin, H. Guler, H. Monard, C. Vallerand
LAL, Orsay, France
A. Loulergue
SOLEIL, Gif-sur-Yvette, France

ThomX Compact X ray source is a 50 MeV storage ring, and a linear accelerator based on a photo-injector. As the electron beam in the ring will not be damped by synchrotron radiation, the transfer line should rely on a precise injection in the ring. In order to fulfill this requirement, especially in terms of optics function and orbit correction, different tools have been prepared and tested on the accelerator toolbox of Matlab Middle Layer. We will present the different tools and the underlying physics for the ThomX transfer line.

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MOPOY006

Preparations for Upgrading the RF Systems of the PS Booster

cavity, impedance, operation, feedback

853

S.C.P. Albright, D. Quartullo, E.N. Shaposhnikova
CERN, Geneva, Switzerland

The accelerators of the LHC injector chain need to be upgraded to provide the HL-LHC beams. The PS Booster, the first synchrotron in the LHC injection chain, uses three different RF systems (first, second and up to tenth harmonic) in each of its four rings. As part of the LHC Injector Upgrade the current ferrite RF systems will be replaced with broadband Finemet cavities, increasing the flexibility of the RF system. A Finemet test cavity has been installed in Ring 4 to investigate its effect on machine performance, especially beam stability, during extensive experimental studies. Due to large space charge impedance Landau damping is lost through most of the cycle in single harmonic operation, but is recovered when using the second harmonic and controlled longitudinal emittance blow-up. This paper compares beam parameters during acceleration with and without the Finemet test cavity. Comparisons were made using beam measurements and simulations with the BLonD code based on a full PS Booster impedance model. This work, together with simulations of future operation, have provided input for the decision to adopt a fully Finemet RF system.

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MOPOY009

ELENA: Installations and Preparations for Commissioning

antiproton, electron, experiment, extraction

860

C. Carli, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, T. Eriksson, R. Ostojić, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany

The Extra Low Energy Antiproton ring (ELENA) is a small 30 m circumference synchroton under construction at CERN to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. Installation of the machine and lines needed for the commissioning of the ring are ongoing and commissioning is expected to start around mid-2016. The aim is to complete ELENA ring commissioning in November followed by the installation of new electrostatic transfer lines to existing experiments until autumn 2017. Status of ELENA installations and preparations for commissioning will be reported.

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MOPOY013

Modeling Longitudinal Dynamics in the Fermilab Booster Synchrotron

booster, impedance, synchrotron, simulation

873

J.-F. Ostiguy, C.M. Bhat, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

Funding: Work performed under U.S. Government contract DE-AC02-07CH11359
The PIP-II project will replace the existing 400 MeV linac with a new, CW-capable, 800 MeV superconducting one. With respect to current operations, a 50% increase in beam intensity in the rapid cycling Booster synchrotron is expected. Booster batches are combined in the Recycler ring; this process limits the allowed longitudinal emittance of the extracted Booster beam. To suppress eddy currents, the Booster has no beam pipe; magnets are evacuated, exposing the beam to core laminations and this has a substantial impact on the longitudinal impedance. Noticeable longitudinal emittance growth is already observed at transition crossing. Operation at higher intensity will likely necessitate mitigation measures. We describe systematic efforts to construct a predictive model for current operating conditions. A longitudinal only code including a laminated wall impedance model, space charge effects, and feedback loops is developed. Parameter validation is performed using detailed measurements of relevant beam, rf and control parameters. An attempt is made to benchmark the code at operationally favorable machine settings.

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MOPOY016

HSI RFQ Upgrade for the UNILAC Injection to FAIR

rfq, bunching, simulation, ion

877

C. Zhang, L. Groening, O.K. Kester, S. Mickat, H. Vormann
GSI, Darmstadt, Germany
M. Baschke, H. Podlech, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany

As an injector to the future FAIR facility, the UNILAC accelerator is required to deliver ion beams with high intensities as well as good beam quality. The electrodes of the current HSI RFQ are exhausted and the current RFQ itself is assigned to be one bottle-neck for improving the brilliance performance of the whole linac. Based on the so-called NFSP (New Four-Section Procedure) method, a new RFQ electrode design has been developed and optimized for 20 emA, U⁴⁺ beams at the RFQ entrance. Since only the electrodes will be replaced, the RFQ length has been kept unchanged. Even with a lowered inter-vane voltage, the new RFQ design has achieved better beam performance compared to the previous design. This paper will focus on the performed study with respect to beam dynamics.

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MOPOY017

Upgrade of the Universal Linear Accelerator UNILAC for FAIR

DTL, ion, rfq, operation

880

L. Groening, A. Adonin, X. Du, R. Hollinger, E. Jäger, M.T. Maier, S. Mickat, A. Rubin, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao, A. Yakushev, C. Zhang
GSI, Darmstadt, Germany
M. Baschke, H. Hähnel, H. Podlech, U. Ratzinger, A. Seibel, R. Tiede
IAP, Frankfurt am Main, Germany
Ch.E. Düllmann, P. Scharrer
HIM, Mainz, Germany

In order to meet the requirements on beam parameters for the upcoming FAIR facility at GSI, the injector linac UNILAC will be upgraded. The activities comprise development of the sources for stable provision of intense uranium beams at a repetition rate of 2.7 Hz, a revision of the beam dynamics layout of the 120 keV/u RFQ, the replacement of the matching section to the 1.4 MeV/u pre-stripper DTL, and enhancement of the gaseous stripping section efficiency. This section shall also include a round-to-flat emittance adaptor to prepare the beam for injection into the synchrotron SIS18 which has a flat transverse injection acceptance. Finally, the upgrade includes the complete replacement of the 40 year old 11.4 MeV/u Alvarez-type post-stripper DTL with a new DTL, preferably using Alvarez-type cavities with improved beam focusing features, as well as its rf-power alimentations.

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MOPOY027

Emittance Measurement with Wire Scanners at C-ADS Injector-I

rfq, simulation, beam-transport, background

910

H. Geng, C. Meng, Y.F. Sui, F. Yan, L. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The transverse emittance at C-ADS injector-I has been measured by the wire scanners at the Medium Energy Beam Transport-I (MEBT1). We have studied the effect of different fitting methods for obtaining the beam sizes on the emittance result, the result will be presented in this paper. The validation study of the quad-scan method with the presence of space charge effect at 10 mA will also be shown, and finally the quad-scan results will be compared with the multi-wire results.

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MOPOY029

Transverse Emittance Measurements in CSNS Linac

focusing, quadrupole, space-charge, linac

916

Z.P. Li, Y. Li, J. Peng, S. Wang
IHEP, Beijing, People's Republic of China

Commissioning of the front-end of the linac at CSNS has been accomplished. Double scanning slit system and wire-scanners were employed to carry out the transverse emittance measurements in both low energy beam transport (LEBT) and medium energy beam transport (MEBT). Different results of different measurement methods are presented and compared. Corresponding codes were developed for each of the emittance measurement methods.

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MOPOY031

Emittance Measurement with Double-Slit Method in CADS Injector-I

solenoid, rfq, linac, simulation

922

C. Meng, H. Geng, Z. Xue, F. Yan, L. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The C-ADS accelerator is a CW (Continuous-Wave) proton linac with 1.5 GeV in beam energy, 10 mA in beam current, and 15 MW in beam power. CADS Injector-I accelerator is a 10-mA 10-MeV CW proton linac, which uses a 3.2-MeV normal conducting 4-Vane RFQ and superconducting single-spoke cavities for accelerating. The 5MeV test stand of CADS accelerator Injector I is composed of an ion source, a LEBT, a 325MHz RFQ, a MEBT, a cryogenic module (CM1) of seven SC spoke cavities (β=0.12) , seven SC solenoids, seven cold BPMs and a beam dump. Emittance measurement is very important for the understanding of beam behavior and matching to the next accelerating section. Detailed emittance measurement with double-slit method after CM1 are presented in this paper.

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MOPOY047

Studies of Ultimate Intensity Limits for High Power Proton Linacs

linac, proton, DTL, rfq

951

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
M.O. Boenig, A.E. Geisler, O. Heid
Siemens AG, Erlangen, Germany
I.V. Konoplev, A. Seryi, S.L. Sheehy
JAI, Oxford, United Kingdom

Although modern high power proton machines can now routinely deliver MW level operating powers, the next generation accelerators will be required to reach powers orders of magnitude higher. Significant developments will be needed both in technology and in understanding the limits of high intensity operation. The present study investigates the beam dynamics in three experimental linac designs when the beam intensity is increased above current levels such that for CW regimes, beam powers of up to 400 MW can be attained. In the first, a 1 A proton beam is accelerated to 400 MeV using normal conducting structures. In the second, a comparison is made when two front ends accelerate 0.5 A beams to ~20 MeV where they are funnelled to 1 A and accelerated to 400 MeV. Similarly, in the third, two 0.25 A beams are funnelled to 0.5 A and then accelerated in superconducting structures to 800 MeV. In addition, alternative unconventional methods of generating high current beams are also discussed. The further studies that are needed to be undertaken in the future are outlined, but it is considered that the three linac configurations found are sufficiently promising for detailed technical designs to follow.

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MOPOY058

Removing Known SPS Intensity Limitations for High Luminosity LHC Goals

impedance, vacuum, simulation, shielding

989

E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, P. Cruikshank, B. Goddard, T. Kaltenbacher, A. Lasheen, J. Perez Espinos, J. Repond, B. Salvant, C. Vollinger
CERN, Geneva, Switzerland

In preparation of the SPS as an LHC injector its impedance was significantly reduced in 1999 - 2000. A new SPS impedance reduction campaign is planned now for the High Luminosity (HL)-LHC project, which requires bunch intensities twice as high as the nominal one. One of the known intensity limitations is a longitudinal multi-bunch instability with a threshold 3 times below this operational intensity. The instability is presently cured using the 4th harmonic RF system and controlled emittance blow-up, but reaching the HL-LHC parameters cannot be assured without improving the machine impedance. Recently the impedance sources responsible for this instability were identified and implementation of their shielding and damping is foreseen during the next long shutdown (2019 - 2020) in synergy with two other important upgrades: amorphous carbon coating of (part of) the vacuum chamber against the e-cloud effect and rearrangement of the 200 MHz RF system. In this paper the strategy of impedance reduction is presented together with beam intensity achievable after its realisation. The potential effect of other proposals on remaining limitations is also considered.

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TUOBA03

Application of Differential Evolution Algorithm in Future Collider Optimization

dynamic-aperture, sextupole, lattice, collider

1025

Y. Zhang
IHEP, Beijing, People's Republic of China
D. Zhou
KEK, Ibaraki, Japan

Funding: Project U1332108 supported by NSFC.
The dynamic aperture of is very limited due to the very small beta at IP in the SuperKEKB. In the storage ring based Higgs factory, the vertical beta function is not so small, but the much larger circumference enlarge the detuning term especially in horizontal direction. It is very hard to optimize the dynamic aperture in the future colliders. The particle loss may comes from different cause for different energy or different transverse coupling. The design of CEPC is still in process. The construction of SuperKEKB is nearly finished, but there still exist some problem which could reduce the performance. There are a few hundred parameters to be varied in the future colliders. The global optimization may be a good way to enlarge the dynamic aperture. Differential Evolution is a very simple population based, stochastic function minimizer which is very powerful at the same time. In this paper we show some application of the algorithm in the two machines. It has the potential to help us optimize the machine.

Slides TUOBA03 [2.289 MB]

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TUOCA03

Commissioning of the European XFEL Injector

gun, laser, controls, operation

1044

F. Brinker
DESY, Hamburg, Germany

The European XFEL Injector consists of an L-Band RF photoinjector, a TESLA type 1.3 GHz module, a 3rd harmonic RF section, a laser heater and an extensive diagnostic section to determine projected and slice properties of the beam. The commissioning of the complete system has been started in December 2015 after several years of construction. We will report on commissioning results and persepctives for the later XFEL operation.

Slides TUOCA03 [5.182 MB]

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TUOAB02

Conditions for CSR Microbunching Gain Suppression

dipole, lattice, synchrotron, synchrotron-radiation

1057

C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
S. Di Mitri
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
D. Douglas, R. Li, C. Tennant
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to*. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver***. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain.
*D.Douglas et al, JLAB-ACP-14-1751, S.DiMitri et al, PRL (2013), R.Hajima, NIMA (2004), Y.Jiao et al, PRSTAB (2014)
**Z.Huang et al, PRSTAB (2004), Saldin et al, NIMA (2004)
***C.Tsai et al, FEL'15

Slides TUOAB02 [6.484 MB]

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TUOBB01

Demonstration of Current Profile Shaping using Double Dog-Leg Emittance Exchange Beam Line at Argonne Wakefield Accelerator

quadrupole, dipole, experiment, wakefield

1065

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, G. Ha, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Emittance exchange (EEX) based longitudinal current profile shaping is the one of the promising current profile shaping technique. This method can generate high quality arbitrary current profiles under the ideal conditions. The double dog-leg EEX beam line was recently installed at the Argonne Wakefield Accelerator (AWA) to explore the shaping capability and confirm the quality of this method. To demonstrate the arbitrary current profile generation, several different transverse masks are applied to generate different final current profiles. The phase space slopes and the charge of incoming beam are varied to observe and suppress the aberrations on the ideal profile. We present current profile shaping results, aberrations on the shaped profile, and its suppression.

Slides TUOBB01 [5.032 MB]

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TUPMR020

In-depth Analysis and Optimization of the European Spallation Source Front End Lattice

rfq, solenoid, space-charge, simulation

1274

Y.I. Levinsen, M. Eshraqi
ESS, Lund, Sweden
L. Celona, L. Neri
INFN/LNS, Catania, Italy

The European Spallation Source front end will deliver a 62.5 mA beam current of 2.8 ms duration at 352 MHz to the downstream linac, which in turn will produce a 5 MW proton beam onto the target. Such unprecedented beam power requires a high quality beam with accurate and stable beam parameters in order to assure low beam losses and safe transport through the linac. In this paper we present advanced tuning methods for the low energy beam transport and the radio frequency quadrupole.

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TUPMR033

Low Emittance Growth in a LEBT with Un-neutralized Section

ion, ion-source, solenoid, vacuum

1317

L.R. Prost, J.-P. Carneiro, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
In a Low Energy Beam Transport line (LEBT), the emittance growth due to the beam's own space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report discusses the experimental realization of such a scheme at Fermilab's PXIE, where low beam emittance dilution was demonstrated

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TUPMR046

Sources of Emittance Growth at the CERN PS Booster to PS Transfer

injection, kicker, optics, betatron

1352

W. Bartmann, J.L. Abelleira, F. Burkart, B. Goddard, J. Jentzsch, R. Ostojić
CERN, Geneva, Switzerland

The CERN PS Booster (PSB) has four vertically stacked rings. After extraction from each ring, the bunches are recombined in two stages, comprising septum and kicker systems, such that the accumulated bunch train is injected through a single line into the PS. Bunches from the four rings go through a different number of vertical bends, which leads to differences in the betatron and dispersion functions due to edge focussing. The fast pulsed systems at PSB extraction, recombination and PS injection lead to systematic errors of delivery precision at the injection point. These error sources are quantified in terms of emittance growth and particle loss. Mitigations to reduce the overall emittance growth at the PSB to PS transfer within the LHC injectors upgrade are presented.

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TUPMW002

LHC Luminosity Modeling for RUNII

luminosity, radiation, scattering, proton

1403

F. Antoniou, G. Arduini, M. Hostettler, M. Lamont, S. Papadopoulou, Y. Papaphilippou, G. Papotti, M. Pojer, B. Salvachua, M. Wyszynski
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
After a long shut-down (LS1), LHC restarted its operation on April 2015 at a record energy of 6.5TeV, achieving soon a good luminosity performance. In this paper, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on the observations, other sources of luminosity degradation are discussed and the model is refined. Finally, based on the experience from runI and runII, the model is used for integrated luminosity projections for the HL-LHC beam parameters.

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TUPMW007

Impact of Long Range Beam-Beam Effects on Intensity and Luminosity Lifetimes from the 2015 LHC Run

luminosity, experiment, hadron, dynamic-aperture

1422

M.P. Crouch, R.B. Appleby
UMAN, Manchester, United Kingdom
D. Banfi, C. Tambasco
EPFL, Lausanne, Switzerland
J. Barranco, R. Bruce, X. Buffat, T. Pieloni, M. Pojer, B. Salvachua, G. Trad
CERN, Geneva, Switzerland
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Research supported by the High Luminosity LHC project
Luminosity is one of the key parameters that determines the performance of colliding beams in the Large Hadron Collider (LHC). Luminosity can therefore be used to quantify the impact of beam-beam interactions on the beam lifetimes and emittances. The High Luminosity Large Hadron Collider (HL-LHC) project aims to reach higher luminosities, approximately a factor of 7 larger than the nominal LHC at peak luminosity without crab cavities. Higher luminosities are achieved by increasing the bunch populations and reducing the transverse beam sizes. This results in stronger beam-beam effects. Here the LHC luminosity and beam intensity decay rates are analysed as a function of reducing beam separation with the aim of characterising the impact of beam-beam effects on the luminosity and beam lifetime. The analysis and results are discussed with possible application to the HL-LHC upgrade.

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TUPMW008

Evolution of the Beam Parameters during Luminosity Production in the Future Circular Hadron Collider

luminosity, collider, scattering, damping

1426

X. Buffat, D. Schulte
CERN, Geneva, Switzerland

The evolution of the beam parameters during luminosity production in the Future Circular Hadron Collider (FCC-hh) is described based on basic models of the effect of synchrotron radiations, intra-beam scattering, luminosity burn-off and beam-beam limitations, allowing for an estimation of the luminosity performance in different running scenarios. It is shown that a large variations of the beam parameters is expected during a cycle. Potential operational schemes adapting to these variations are considered.

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TUPMW009

Simulation of Head-on Beam-Beam Limitations in Future High Energy Colliders

simulation, synchrotron, collider, radiation

1430

X. Buffat, T. Pieloni, C. Tambasco
CERN, Geneva, Switzerland
J. Barranco, A. Florio
EPFL, Lausanne, Switzerland

The Future Circular Hadron Collider (FCC-hh) project calls for studies in a new regime of beam-beam interactions. While the emittance damping due to synchrotron radiation is still slower than in past or existing lepton colliders, it is significantly larger than in other hadron colliders. The slow reduction of the emittance is profitable for higher luminosity in term of transverse beam size at the interaction points and also to mitigate long-range beam-beam effects, potentially allowing for a reduction of the crossing angle between the beams during the operation. In such conditions, the strength of head-on beam-beam interactions increases, potentially limiting the beam brightness. 4D weak-strong and strong-strong simulations are performed in order to assess these limitations.

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TUPMW013

Experimental Demonstration of β* Leveling at the LHC

luminosity, betatron, controls, experiment

1442

A.A. Gorzawski, D. Mirarchi, B. Salvachua, J. Wenninger
CERN, Geneva, Switzerland

The HL-LHC project foresees to boost the LHC peak luminosity beyond the capabilities of the LHC experimental detectors. Leveling the luminosity down to a constant value that is sustainable for the experiments is therefore the operational baseline of HL-LHC. Various luminosity leveling techniques are available at the LHC. Leveling by adjusting β^*, the betatron function at the interaction point, to maintain a constant luminosity is favorable because the beams remain head-on which provides optimal stability from the point of view of collective effects. Smooth leveling by β^* requires however excellent control of the beam orbits and beam losses in the interaction regions since the beam offsets should not vary by more than around one r.m.s. beam size during the process. This leveling scheme has been successfully tested and experimentally demonstrated during the LHC machine development program in 2015. This paper presents results on luminosity leveling over a β^* range from 10 m to 0.8 m and provides an outlook on future developments and use of this technique at the LHC.

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TUPMW022

Modelling and Measurements of Bunch Profiles at the LHC Flat Bottom

lattice, scattering, radiation, damping

1477

S. Papadopoulou, F. Antoniou, J.E. Muller, Y. Papaphilippou, G. Trad
CERN, Geneva, Switzerland

At the LHC flat bottom the interplay between a series of effects (i.e. intrabeam scattering, longitudinal beam manipulations, non-linearities of the machine, etc) can lead to a population of the tails of the beam distributions, which may become non-Gaussian. This paper presents observations of the evolution of particle distributions in the LHC flat bottom. Novel distribution functions are employed to represent the beam profiles, and used as a guideline for generalising emittance growth rate estimations due to IBS. Finally, an attempt is made to benchmark an IBS Monte-Carlo simulation code, able to track 3D particle distributions, with the measured beam profile evolutions.

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TUPMW034

A 200 MHz SC-RF System for the HL-LHC

cavity, injection, luminosity, impedance

1513

R. Calaga, R. Tomás
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project
A quarter wave β=1 superconducting cavity at 200 MHz is proposed for the LHC as an alternative to the present 400 MHz RF system. The primary motivation of such a system would be to accelerate higher intensity and longer bunches with improved capture efficiency. Advantages related to minimizing electron cloud effects, intra-beam scattering, heating and the possibility of luminosity levelling with bunch length are described. Some considerations related to cavity optimization, beam loading and technological challenges are addressed.

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TUPMW035

Performance and Operational Aspects of HL-LHC Scenarios

luminosity, optics, simulation, electron

1516

L.E. Medina Medrano
DCI-UG, León, Mexico
R. Tomás
CERN, Geneva, Switzerland

Funding: Research supported by the High Luminosity LHC project. Work supported by the Beam Project (CONACYT, Mexico).
Several alternatives to the present HL-LHC baseline configuration have been proposed, aiming either to improve the potential performance, reduce its risks, or to provide options for addressing possible limitations or changes in its parameters. In this paper we review and compare the performance of the HL-LHC baseline and the main alternatives with the latest parameters set. The results are obtained using refined simulations of the evolution of the luminosity with β^*-levelling, for which new criteria have been introduced, such as improved calculation of the intrabeam scattering and the addition of penalty steps to take into account the necessary time to move between consecutive optics during the process. The features of the set of optics are discussed for the nominal baseline.

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TUPMW038

RHIC Operation with Asymmetric Collisions in 2015

proton, operation, injection, cavity

1527

C. Liu, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, G. Narayan, S.K. Nayak, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, G. Wang, K. Yip, A. Zaltsman, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Collisions with beams of highly asymmetric rigidities (proton-Gold and proton-Aluminum) were provided for the RHIC physics programs in 2015. Magnets were moved for the first time in RHIC prior to the run to accommodate the asymmetric beam trajectories during acceleration and at store. A special ramping scheme was designed to keep the revolution frequencies of the beams in the two rings equal. The unique operational experience of the asymmetric run will be reviewed.

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TUPMW039

Measurement of the Total Cross Section of Gold-Gold Collisions at sqrt {s_NN}=200 GeV

luminosity, ion, heavy-ion, collider

1530

W. Fischer, A.J. Baltz, M. Blaskiewicz, K.A. Drees, D.M. Gassner, Y. Luo, M.G. Minty, P. Thieberger
BNL, Upton, Long Island, New York, USA
I.A. Pshenichnov
RAS/INR, Moscow, Russia

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
Heavy ion collision cross sections totaling several hundred barns have been calculated previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). These total cross sections are more than one order of magnitude larger than the geometric ion-ion cross sections, primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for RHIC and the LHC, where some collision products are lost in cryogenically cooled magnets. These losses have the potential to affect power and signal electronic devices and quench superconducing magnets. We have previously reported the total cross section measurement of U+U collisions at a center-of-mass energy of 192.8 GeV per nucleon-pair. Here we present the equivalent analysis for Au+Au collisions with the data available from a low-intensity store of RHIC Run in 2014.

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TUPMY001

Very Low Emittance Muon Beam using Positron Beam on Target

positron, target, collider, electron

1536

M. Antonelli, M.E. Biagini, M. Boscolo, A. Variola
INFN/LNF, Frascati (Roma), Italy
E. Bagli
INFN-Ferrara, Ferrara, Italy
G. Cavoto
INFN-Roma, Roma, Italy
P. Raimondi
ESRF, Grenoble, France

Muon beams are customarily obtained via K/π decays produced in proton interaction on target. In this paper we investigate the possibility to produce low emittance muon beams from electron-positron collisions at centre-of-mass energy just above the μ⁺{+}μ⁺{-} production threshold with maximal beam energy asymmetry, corresponding to a positron beam of about 45 GeV interacting on electrons on target. Performances on both amorphous and crystal target are presented, and the general scheme for the muon production will be given. We present the main features of this scheme with a first preliminary evaluation of the performances that could be achieved by a multi-TeV muon collider.

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TUPMY002

APF IH-DTL Design for the Muon LINAC in the J-PARC Muon g-2/EDM Experiment

cavity, linac, DTL, acceleration

1539

M. Otani, T. Mibe, M. Yoshida
KEK, Tsukuba, Japan
K. Hasegawa, Y. Kondo
JAEA, Ibaraki-ken, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The muon linac for the J-PARC muon g-2/EDM experiment consists of RFQ (324 MHz), IH-DTL (324 MHz), DAW coupled cell linac (1.3 GHz), and disk loaded structure (1.3 GHz). Because muon has finite life time, the muons should be accelerated in a sufficiently short period. To realize fast acceleration, Alternative Phase Focusing (APF) scheme is adopted in IH-DTL in which the muons are accelerated from 0.34 MeV to about 4 MeV. In this poster, the design of the APF IH-DTL for muon acceleraiton with the computer calculation will be presented.

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TUPMY004

The MICE Demonstration of Muon Ionization Cooling

lattice, betatron, simulation, experiment

1547

J.-B. Lagrange, C. Hunt, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE
Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions up to several TeV at the Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate muon ionization cooling, the technique proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam traverses a material (the absorber) loosing energy, which is replaced using RF cavities. The combined effect is to reduce the transverse emittance of the beam (transverse cooling). The configuration of MICE required to deliver the demonstration of ionization cooling is being prepared in parallel to the execution of a programme designed to measure the cooling properties of liquid-hydrogen and lithium hydride. The design of the cooling-demonstration experiment will be presented together with a summary of the performance of each of its components and the cooling performance of the experiment.
Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution

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TUPMY006

MICE Step IV Optics without the M1 Coil in SSD

lattice, solenoid, simulation, scattering

1553

A. Liu
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the only technique that, given the short muon lifetime, can reduce the phase-space volume occupied by a muon beam quickly enough. MICE will demonstrate cooling in two steps. In the first one, Step IV, MICE will study the multiple Coulomb scattering in liquid hydrogen (LH2) and lithium hydride (LiH). A focus coil module will provide focussing on the absorber. The transverse emittance will be measured upstream and downstream of the absorber in two spectrometer solenoids (SS). Magnetic fields generated by two match coils in the SSs allow the beam to be matched into a flat-field regions in which the tracking detectors are installed. An incident in September 2015 rendered matching coil \#1 (M1D) of the downstream spectrometer inoperable. A new Step IV lattice without M1D and its optimization via a Genetic Algorithm (GA) will be described in this paper.

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TUPMY010

Status of Mice Step IV

factory, experiment, optics, scattering

1562

P.M. Hanlet
IIT, Chicago, Illinois, USA

Funding: STFC, DOE, NSF, INFN, CHIPP AND MORE
Muon beams of low emittance provide the basis for the intense, well characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling–the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam. MICE is being constructed in a series of Steps. The configuration currently in operation at the Rutherford Appleton Laboratory is optimised for the study the properties of liquid hydrogen and lithium hydride that affect cooling. The plans for data taking in the present configuration will be described together with a summary of the status of preparation of the experimental configuration by which MICE will demonstration the principle of ionization cooling.
Submitted by the MICE speakers bureau that will identify later a member of the collaboration to present the contribution

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TUPMY011

Simulated Measurements of Cooling in Muon Ionization Cooling Experiment

lattice, solenoid, detector, electron

1565

T.A. Mohayai
IIT, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Fermilab, Batavia, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Cooled muon beams set the basis for the exploration of physics of flavour at a Neutrino Factory and for multi-TeV collisions at a Muon Collider. The international Muon Ionization Cooling Experiment (MICE) measures beam emittance before and after an ionization cooling cell and aims to demonstrate emittance reduction in muon beams. In the current MICE Step IV configuration, the MICE muon beam passes through low-Z absorber material for reducing its transverse emittance through ionization energy loss. Two scintillating fiber tracking detectors, housed in spectrometer solenoid modules upstream and downstream of the absorber are used for reconstructing position and momentum of individual muons for calculating transverse emittance reduction. However, due to existence of non-linear effects in beam optics, transverse emittance growth can be observed. Therefore, it is crucial to develop algorithms that are insensitive to this apparent emittance growth. We describe a different figure of merit for measuring muon cooling which is the direct measurement of the phase space density.

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TUPMY012

Hybrid Methods for Simulation of Muon Ionization Cooling Channels

simulation, experiment, scattering, lattice

1568

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

Funding: Work is supported by the U.S. Department of Energy.
COSY Infinity is an arbitrary-order beam dynamics simulation and analysis code. It can determine high-order transfer maps of combinations of particle optical elements of arbitrary field configurations. New features are being developed for inclusion in COSY to follow the distribution of charged particles through matter. To study in detail some of the properties of muons passing through material, the transfer map approach alone is not sufficient. The interplay of beam optics and atomic processes must be studied by a hybrid transfer map–Monte Carlo approach in which transfer map methods describe the deterministic behavior of the particles in the accelerator channel, and Monte Carlo methods are used to model the stochastic processes intrinsic to liquid and solid absorbers. The advantage of the new approach is that the vast majority of the dynamics is represented by fast application of the high-order transfer map of an entire element and accumulated stochastic effects. The gains in speed are expected to simplify the optimization of muon cooling channels which are usually very computationally demanding. Progress on the development of the required algorithms is reported.

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TUPMY013

Progress on Beam-Plasma Effect Simulations in Muon Ionization Cooling Lattices

plasma, simulation, scattering, space-charge

1571

J.S. Ellison
IIT, Chicago, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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TUPMY030

Measurements of Transmitted Electron Beam Extinction through Si Crystal Membranes

electron, scattering, laser, experiment

1611

E.A. Nanni, R.K. Li, C. Limborg, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA
W.S. Graves, R. Kirian, J. Spence, U. Weierstall
Arizona State University, Tempe, USA

A recently proposed method for the generation of relativistic electron beams with nanometer-scale current modulation requires diffracting relativistic electrons from a perfect crystal Si grating, accelerating the diffracted beam and imaging the crystal structure into the temporal dimension via emittance exchange. The relative intensity of the current modulation is limited by the ability to extinguish the transmitted beam via diffraction with a single-crystal Si membrane. In these preliminary experiments we will measure the extinction of the transmitted electron beam at zero scattering angle due to multiple Bragg scattering from a Si membrane with a uniform thickness of 340 nm at 2.35 MeV using the SLAC UED facility. The impact of beam divergence and charge density at the Si target will be quantified. The longevity of the Si membrane will also be investigated by monitoring the diffraction pattern as a function of time to observe the potential onset of damage to the crystal.

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TUPMY031

Estimation and Suppression of Aberrations in Emittance Exchange based Current Profile Shaping

collective-effects, space-charge, acceleration, FEL

1615

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
W. Gai, G. Ha, K.-J. Kim, J.G. Power
ANL, Argonne, Illinois, USA

The longitudinal current profile manipulation has been explored for many applications including THz radiation, FEL and advanced acceleration schemes. Especially, collinear dielectric wakefield accelerations require a microbunch shaping for a high transformer ratio. We have studied aberrations from the emittance exchange based current profile shaping to preserve the high transformer ratio. All second order aberration terms in the double dog-leg emittance exchange beam line are discovered. Aberration patterns from each aberration sources like second order terms, space-charge, and CSR and their effect on the transformer ratio are estimated analytically. These aberration sources and corresponding patterns are confirmed using a particle tracking code GPT. Simple methods to suppress each aberration will be presented too. All calculation in this work is done with a double dog-leg emittance exchange beam line.

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TUPMY044

Carbon and Mercury Target Systems for Muon Colliders and Neutrino Factories

target, proton, collider, factory

1641

K.T. McDonald
PU, Princeton, New Jersey, USA
J.S. Berg, H.G. Kirk, D. Stratakis
BNL, Upton, Long Island, New York, USA
X.P. Ding
UCLA, Los Angeles, California, USA

Funding: Work supported in part by US DOE Contract NO. DE-AC02-98CH110886
A high-power target is required to convert a powerful MW-class proton beam into an intense muon source or neutrino source in support of physics at the intensity frontier. The first phase of a Muon Collider or Neutrino Factory program may use a 6.75-GeV proton driver with beam power of only 1 MW. At this lower power it is favorable to use a graphite target with beam and target tilted slightly to the axis of a 20-T pion-capture solenoid around the target. Using the MARS15 (2014) code, we optimized the geometric parameters of the beam and target to maximize particle production at low energies by an incoming proton beam with kinetic energy of 6.75 GeV impinging on this carbon target. We also studied beam-dump configurations to suppress the rate of undesirable high-energy secondary particles in the beam. For a possible upgrade to a proton beam of multi-MW power, we considered a free-flowing mercury jet.

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TUPOR009

Single Bunch Longitudinal Instability in the CERN SPS

impedance, simulation, flattop, synchrotron

1670

A. Lasheen, T. Bohl, S. Hancock, T. Roggen, E.N. Shaposhnikova
CERN, Geneva, Switzerland
E. Radvilas
Gediminas Technical University, Vilnius, Lithuania

The longitudinal single bunch instability observed in the SPS leads to uncontrolled emittance blow-up and limits the quality of high intensity beams required for the High Luminosity LHC and AWAKE projects at CERN. The present SPS impedance model developed from a thorough survey of machine elements was used in macro-particle simulations (with the code BLonD) of the bunch behavior through the acceleration cycle. Comparison of simulations with measurements of the synchrotron frequency shift, performed on the SPS flat bottom to probe the impedance, show a reasonable agreement. During extensive experimental studies various beam and machine parameters (bunch intensity, longitudinal emittance, RF voltage, with single and double RF systems) were scanned in order to further benchmark the SPS impedance model with measurements and to better understand the mechanism behind the instability. It was found that the dependence of instability threshold on longitudinal emittance and beam energy has an unexpected non-monotonic behavior, leading to islands of (in)stability. The results of this study are presented and can be used to define possible parameter settings for the future CERN projects.

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TUPOR010

Simulation of Instability at Transition Energy with a New Impedance Model for CERN PS

impedance, simulation, proton, synchrotron

1674

N. Wang
IHEP, Beijing, People's Republic of China
S. Aumon, N. Biancacci, M. Migliorati, G. Sterbini, N. Wang
CERN, Geneva, Switzerland
M. Migliorati
INFN-Roma1, Rome, Italy
S. Persichelli
University of Rome La Sapienza, Rome, Italy

Instabilities driven by the transverse impedance are proven to be one of the limitations for the high intensity reach of the CERN PS. Since several years, fast single bunch vertical instability at transition energy has been observed with the high intensity bunch serving the neu-tron Time-of-Flight facility (n-ToF). In order to better understand the instability mechanism, a dedicated meas-urement campaign took place. The results were compared with macro-particle simulations with PyHEADTAIL based on the new impedance model developed for the PS. Instability threshold and growth rate for different longitu-dinal emittances and beam intensities were studied.

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TUPOR011

Study of Microwave Instability for SLS-2

impedance, vacuum, storage-ring, simulation

1678

H.S. Xu, P. Craievich, M.M. Dehler, L. Stingelin
PSI, Villigen PSI, Switzerland

An ultra-low emittance electron storage ring is under development for the Upgrade of Swiss Light Source (SLS-2). An antechamber scheme consisting of round beam channel with 10 mm inner radius is considered to accommodate the required strong quadrupole and sextupole magnets, achieve the ultra-high vacuum, and absorb the undesired synchrotron radiation. However, the small size of vacuum chamber increases the susceptibility of the beam to the impedance induced collective instabilities. We will present the preliminary study of the microwave instability for SLS-2 storage ring considering the longitudinal Resistive-Wall (RW) impedance due to three different options for the beam chamber. The microwave instability thresholds are calculated under the conditions of two possible RF frequencies (100 MHz and 500 MHz) and three different materials (aluminum, copper, and stainless steel). The influences of third-harmonic cavities are also studied.

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TUPOR017

Beam-beam Simulation of Crab Cavity with Frequence Dependent Noise for LHC Upgrade

luminosity, cavity, simulation, feedback

1691

J. Qiang
LBNL, Berkeley, California, USA
G. Arduini, Y. Papaphilippou, T. Pieloni
CERN, Geneva, Switzerland
J. Barranco
EPFL, Lausanne, Switzerland

High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the frequence-dependent crab cavity noise on the beam luminosity lifetime using strong-strong beam-beam simulations.

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TUPOR019

RF Injector Beam Dynamics Optimization and Injected Beam Energy Constraints for LCLS-II

cavity, laser, electron, gun

1699

C.E. Mitchell, H.J. Qian, J. Qiang, F. Sannibale, M. Venturini
LBNL, Berkeley, California, USA
P. Emma, T.O. Raubenheimer, J.F. Schmerge, F. Zhou
SLAC, Menlo Park, California, USA

Funding: Work supported by the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231.
LCLS-II is a proposed high-repetition rate (>1 MHz) Free Electron Laser (FEL) X-ray light source, based on a CW, superconducting linac, to be built at SLAC National Accelerator Laboratory. The injector technology is based on a high-repetition rate RF photoinjector gun developed as part of the Advanced Photoinjector Experiment (APEX) at Lawrence Berkeley National Laboratory. Exploration of the injector design settings is performed using a multiobjective genetic optimizer to optimize the beam quality at the injector exit (~100 MeV). In this paper, we describe the current status of LCLS-II injector design optimization, with a focus on the sensitivity of the optimized solutions to the beam energy at the injector exit, which is constrained by the requirements of the downstream laser heater system.

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TUPOR021

Incoherent Vertical Emittance Growth from Electron Cloud at CesrTA

simulation, dipole, electron, positron

1707

S. Poprocki, J.A. Crittenden, S.N. Hearth, J.D. Perrin, D. L. Rubin, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the US National Science Foundation PHY-1416318, PHY-0734867, and PHY-1002467, and the U.S. Department of Energy DE-FC02-08ER41538
We report on measurements of electron cloud (EC) induced tune shifts and emittance growth at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) with comparison to tracking simulation predictions. The simulations are based on a weak-strong model of the interaction of the positron beam (weak) with the electron cloud (strong), using electric fields computed with established EC buildup simulation codes (ECLOUD). Experiments were performed with 2.1 GeV positrons in a 30 bunch train with 14 ns bunch spacing and 9 mm bunch length, plus a witness bunch at varying distance from the train to probe the cloud as it decays. Measurements of the horizontal and vertical coherent tune shifts and horizontal and vertical bunch size were obtained for a range of train and witness bunch currents, and compared to simulations.

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TUPOW003

High Average RF Power Tests With 2 RF Vacuum Windows at PITZ

gun, operation, vacuum, Windows

1744

Y. Renier, G. Asova, M. A. Bakr, P. Boonpornprasert, J.D. Good, M. Groß, C. Hernandez-Garcia, H. Huck, I.I. Isaev, D.K. Kalantaryan, M. Krasilnikov, O. Lishilin, G. Loisch, D. Malyutin, D. Melkumyan, A. Oppelt, M. Otevřel, G. Pathak, T. Rublack, I.V. Rybakov, F. Stephan, G. Vashchenko, Q.T. Zhao
DESY Zeuthen, Zeuthen, Germany
M. Bousonville, S. Choroba, S. Lederer
DESY, Hamburg, Germany

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), was built with the aim to develop and characterize electron sources for future usage at FLASH and at the European XFEL. Recently, the main focus at PITZ has been the study of gun reliability and photoinjector performance at high average power. The goal is to get stable and reliable operation with 6.4 MW peak power in the gun at 650 us RF pulse length and 10 Hz repetition rate. To achieve this, a new RF feed system with two RF windows was installed at PITZ in 2014. During this test, the old gun 4.2 with a modified back-plane design for better cathode contact has been used. In this contribution the results of the RF conditioning of gun 4.2 with a detailed interlock analysis will be reported as well as results from recent electron beam characterization.

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TUPOW006

Six-dimensional Phase-space Rotation and its Applications

FEL, cathode, simulation, electron

1754

M. Kuriki, K. Negishi
HU/AdSM, Higashi-Hiroshima, Japan
H. Hayano, R. Kato, K. Ohmi, M. Satoh, Y. Seimiya, J. Urakawa
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Funding: This work is partly supported by Grant-in-Aid for Scientific Research by MEXT, Japan (KAKENHI) 25390126.
Recent progress on the accelerator science requires optimized phase space distributions of the beam for each applications. A classical approach to satisfy the requirements is minimizing the beam emittance with a bunch charge as much as possible. This classical approach is not efficient and not compatible to the beam dynamics nature. 6D phase-space rotation, e.g. z-x and x-y, gives a way to optimize the phase space distribution for various applications. In this article, we discus possible applications of the 6D phase space rotation. The x-y rotation generates the high aspect ratio beam for linear colliders directly without DR (Damping Ring). Combination of bunch clipping with a mechanical slit and x-z rotation can generate micro-bunch structure which is applicable for FEL enhancement and drive beam for dielectric acceleration. We present our theoretical and simulation study on these applications.

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TUPOW011

Profile Measurements of Bremsstrahlung Gamma-Rays from Tungsten Plates for Radioactive Isotope Production via Photonuclear Reaction using a 60 MeV Electron Linac

electron, quadrupole, detector, simulation

1766

K. Takahashi, H. Hama, F. Hinode, S. Kashiwagi, H. Kikunaga, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, T. Suda, C. Tokoku, K. Tsukada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Radioactive isotopes have been produced via photo-nuclear reaction using a 60 MeV high-power electron linac for research fields of nuclear chemistry and radioac-tive analysis at Research Center for Electron Photon Science (ELPH), Tohoku University. The electron beam with an average current more than 100 μA is transported to an electron-bremsstrahlung gamma-ray converter of 2 mm thickness platinum or tungsten plate at the irradiation station. A target of 10 mm diameter is placed 3 cm behind a converter. It is enclosed with a quartz glass in the water cooling system and is irradiated for photonuclear reaction. Since the correlation between the spatial profile of bremsstrahlung gamma-rays at the target position and accelerator parameters is of our primary interest, nickel thin films are irradiated and the profiles of bremsstrahlung gamma-rays are measured by intensity distribution measurements of 57Ni radioactivity using the phosphorus imaging plate. In the meantime, the beam emittance and Twiss parameters are measured.

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TUPOW026

Optimization of Electron Beam Properties for Generation of Coherent THz Undulator Radiation at PBP-CMU Linac Laboratory

radiation, undulator, electron, linac

1803

N. Chaisueb, S. Rimjaem, J. Saisut, C. Thongbai
Chiang Mai University, Chiang Mai, Thailand

Funding: This work has been supported by the CMU Junior Research Fellowship Program, the Department of Physics and Material Science, Chiang Mai University, and the Science Achievement Scholarship of Thailand.
Relativistic femtosecond electron bunches produced from the linear accelerator at the Plasma and Beam (PBP) Physics Research Facility are currently used to generate THz radiation via transition radiation. An upgrade to increase the intensity of the THz radiation by using a coherent undulator radiation method is conducted. Optimizations, measurements and analysis of the electron beam properties, which include current, energy and energy spread as well as electron bunch length, are performed to investigate the capability of electron beam production from the current accelerator system. This is also to estimate the possibility to produce the coherent undulator radiation of the PBP-CMU linac. Expected characteristics of the coherent undulator radiation are studied and reported in this contribution.
The authors would like to acknowledge the financial support to participate this conference by the Department of Physics and Material Science and the Graduate School, Chiang Mai University.

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TUPOW032

Modelling of the Short Bunch Optics for BERLinPro

linac, simulation, space-charge, booster

1820

A. Ginter, A.N. Matveenko
HZB, Berlin, Germany

The Energy Recovery Linac principle allows compressing electron bunches to lengths at least two orders of magnitude shorter compared to storage rings. At BERLinPro bunch compression and decompression can be done in two stages in the injector and main arcs. Starting with different bunch lengths from the gun the distribution of compression between these two stages is subject to optimization. Simulations show that the length and shape of the bunch in the injector and before the linac are the limiting factors for minimal bunch length. Injector simulations have to consider space charge effects, whereas CSR effects are limiting compression in the arcs. The strength of these effects and optimal compression ratios changes with different bunch charges. Optimization and simulation tools have to be chosen according to the energy regime and dominant collective effects. Current status of injector optimization and effect on the compressed bunch are presented.

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TUPOW036

Recent Developments and Operational Status of the Compact ERL at KEK

operation, linac, laser, gun

1835

T. Obina, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondo, T. Konomi, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, S. Sasaki, K. Satoh, Y. Seimiya, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, N. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
QST, Tokai, Japan
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The Compact Energy Recovery Linac (cERL) at KEK is a test accelerator in order to develop key components to realize remarkable ERL performance as a future light source. After the beam commissioning in December 2013, the legal current limit has been increased step-by-step like 1 uA, 10 uA, and 100 uA. Survey for the source of beam losses has been conducted in each step, and the study on beam dynamics and tuning has also been carried out. As a next step, 1 mA operation is scheduled in February 2016. In parallel to the increase in beam current, a laser Compton scattering (LCS) system which can provide high-flux X-ray to a beamline has been successfully commissioned. We report recent progress in various kinds of beam tuning: improvement of electron gun performance, high bunch charge operation, mitigation of beam losses, LCS optics tuning and bunch compression for THz radiation.

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TUPOW041

Optimization Studies for the Beam Dynamic in the RF Linac of the ELI-NP Gamma Beam System

electron, laser, linac, photon

1850

C. Vaccarezza, D. Alesini, M. Bellaveglia, M.E. Biagini, G. Di Pirro, A. Gallo, A. Ghigo, S. Guiducci, A. Vannozzi, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci, I. Drebot, D.T. Palmer, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
G. Campogiani
Rome University La Sapienza, Roma, Italy
A. Giribono, A. Mostacci, L. Palumbo
University of Rome La Sapienza, Rome, Italy
V. Petrillo
Universita' degli Studi di Milano & INFN, Milano, Italy
L. Sabbatini
Consorzio Laboratorio Nicola Cabibbo, Frascati, Italy

The ELI-NP GBS is an high spectral density and monochromatic gamma ray source based upon the inverse Compton scattering effect now under construction in Magurele. Its relevant specifications are brilliance higher than 10²¹, 0.5% monochromaticity and a 0.2-19.5 MeV energy tunability. Strong requirements are set for the electron beam dynamic: the control of both the transverse normalized emittance and the energy spread to optimize the spectral density and guarantee the mono chromaticity of the emitted radiation. On this basis the RF Linac optimization has been performed for the designed energy range; a sensitivity analysis of the machine to possible jitters, errors and so on has been also performed, the simulations results hare here presented.

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TUPOW045

Pre-bunched Electron Beam Emittance Simulation and Measurement

electron, simulation, gun, radiation

1864

Yu.D. Kliuchevskaia, S.M. Polozov
MEPhI, Moscow, Russia
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

LUCX facility at KEK is used as the high brightness pre-bunched electron beam source for radiation experiments. Emittance measurement and optimization is one of the important research activities for newly developed operation mode of the facility. Characterization of the pre-bunched beam (THz sequence of a hundred femtosecond bunches) properties opens a possibility to establish detailed simulation of the THz FEL radiation yield and continuously improve pre-bunched beam dynamics insight. Emittance has been measured by the Q-scan method. The measurement results and possible ways of emittance optimization are discussed. The measurement results are compared with beam dynamics simulation done by self-consistent BEAMDULAC-BL code.

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TUPOW049

Expected Results From Channeling Radiation Experiments at Fast

photon, detector, electron, background

1873

T. Sen, D.R. Broemmelsiek, D.R. Edstrom
Fermilab, Batavia, Illinois, USA
J. Hyun
Sokendai, Ibaraki, Japan
D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Funding: Fermilab is operated by Fermi Research Alliance LLC under DOE contract No. DE-AC02CH11359
The photoinjector at the new Fermilab FAST facility will accelerate electron beams to about 50 GeV. After initial beam commissioning, channeling radiation experiments to generate hard X-rays will be performed. In the initial stage, low bunch charge beams will be used to keep the photon count rate low and avoid pile up in the detector. We report here on the optics solutions, the expected channaling spectrum including background from bremmstrahlung and the use of a Compton scatterer for higher bunch charge operation.

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TUPOY022

A Fixed Field Alternating Gradient Accelerator for Helium Therapy

ion, proton, acceleration, injection

1953

J. Taylor
IIAA, Huddersfield, United Kingdom
T.R. Edgecock, R. Seviour
University of Huddersfield, Huddersfield, United Kingdom
S. Green
University Birmingham, Birmingham, United Kingdom
C. Johnstone
PAC, Batavia, Illinois, USA

A non-scaling fixed field alternating gradient (nsFFAG) accelerator is being designed for helium ion therapy. This facility will consist of 2 nested superconducting rings, treating with helium ions (He²⁺) and image with hydrogen ions (H²⁺). Compared to protons, ions deliver a more conformal dose with a significant reduction in range straggling and beam broadening. Carbon ions are currently used and there are no current facilities providing helium therapy. We are investigating the feasibility of an FFAG approach for helium therapy, which has never been previously considered. We investigate emittance and demonstrate that the machine meets isochronicity requirements for fixed frequency RF.

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TUPOY027

Beam Dynamics Studies into Grating-based Dielectric Laser-driven Accelerators

electron, laser, accelerating-gradient, simulation

1970

Y. Wei, S.P. Jamison, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
K. Hanahoe, Y. M. Li, G.X. Xia
UMAN, Manchester, United Kingdom
S.P. Jamison
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom
Y. Wei, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under grant agreement 289191 and the STFC under the Cockcroft Institute core grant ST/G008248/1.
Dielectric laser-driven accelerators (DLAs) based on gratings confine an electromagnetic field induced by a drive laser into a narrow vacuum channel where electrons travel and are accelerated. This can provide an alternative acceleration technology compared to conventional rf cavity accelerators. Due to the achievable high acceleration gradient of up to several GV/m this could pave the way for future ultra-short and low costμaccelerators. This contribution presents detailed beam dynamics simulations for multi-period double grating structures. Using the computer code VSim and realistic beam distributions, the achievable acceleration gradient and final beam quality in terms of emittance and energy spread are discussed. The results are then used for an overall optimization of the accelerating structure.

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WEXA01

The ESRF Low-emittance Upgrade

lattice, dipole, vacuum, radiation

2023

P. Raimondi
ESRF, Grenoble, France

This talk focuses on novel aspects of the lattice design, describes the technical solutions that have been found for meeting the design goals (including the use of permanent magnet dipoles), outlines the main challenges that will be faced in commissioning and operating the new lattice in a very demanding parameter regime, and discusses how it is hoped to maximize eventual benefits for users while minimizing disruption during the upgrade process.

Slides WEXA01 [23.005 MB]

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WEOAA01

Transverse Emittance Exchange for Improved Injection Efficiency

resonance, coupling, synchrotron, injection

2028

P. Kuske, F. Kramer
HZB, Berlin, Germany

In most cases beam is injected into electron storage rings in the horizontal plane and off-axis. The larger the horizontal emittance of the injected beam the larger the acceptance of the ring has to be. The injected beam is usually delivered by a synchrotron. In case the vertical acceptance of the ring is sufficiently large one can take advantage of the small vertical emittance reached in well aligned and tuned synchrotrons since the transverse emit-tances can be exchanged with the help of skew quadru-pole magnets. A few possible processes will be discussed: emittance exchange with static magnets in the transfer line between synchrotron and ring or emittance exchange in the synchrotron shortly before extraction with time dependent magnets. This could be a suddenly switched-on normal or skew quadrupole magnet or skew quadru-pole fields oscillating at a frequency fulfilling the reso-nance condition. Estimates for these magnets and their design will be given.

Slides WEOAA01 [0.852 MB]

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WEOBA02

Commissioning of the China-ADS Injector-I Testing Facility

rfq, simulation, proton, cavity

2048

F. Yan, J.S. Cao, Y.L. Chi, R. Ge, H. Geng, S. Gu, D.Z. Guo, T.M. Huang, X. Jing, H. Li, R.L. Liu, F. Long, C. Meng, H.F. Ouyang, W.M. Pan, Q.L. Peng, Y.F. Sui, J.L. Wang, S.C. Wang, Z. Xue, Q. Ye, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The 10 MeV accelerator-driven subcritical system (ADS) Injector I test stand at Institute of High Energy Physics (IHEP) is a testing facility dedicated to demonstrate one of the two injector design schemes [Injector Scheme-I, which works at 325 MHz], for the ADS project in China. The ion source was installed since April of 2014, periods of commissioning are regularly scheduled between installation phases of the rest of the injector. 6.05 MeV proton energy has been achieved with average beam current of 10 mA by 7 SC spoke cavities at present. This contribution reports the details of the commissioning results together with the challenges of the CW machine commissioning.

Slides WEOBA02 [5.243 MB]

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WEOBA03

High Brilliance Uranium Beams for FAIR

brilliance, ion, target, injection

2052

W.A. Barth, A. Adonin, Ch.E. Düllmann, M. Heilmann, R. Hollinger, E. Jäger, O.K. Kester, J. Khuyagbaatar, J. Krier, E. Plechov, P. Scharrer, W. Vinzenz, H. Vormann, A. Yakushev, S. Yaramyshev
GSI, Darmstadt, Germany
Ch.E. Düllmann, J. Khuyagbaatar, P. Scharrer, A. Yakushev
HIM, Mainz, Germany
Ch.E. Düllmann
Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany
P. Scharrer
Mainz University, Mainz, Germany

The 40 years old GSI-UNILAC (Universal Linear Accelerator) as well as the heavy ion synchrotron SIS18 will serve as a high current heavy ion injector for the new FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100. Due to an advanced machine investigation program in combination with the ongoing UNILAC upgrade program, a new uranium beam intensity record (10 emA, U²⁹⁺) at very high beam brilliance was achieved recently in a machine experiment campaign. This is an important step paving the way to fulfill the FAIR heavy ion high intensity beam requirements. Results of high current uranium beam measurements applying a newly developed pulsed hydrogen gas stripper (at 1.4 MeV/u) will be presented in detail.

Slides WEOBA03 [2.281 MB]

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WEOCA01

Operation of the LHC with Protons at High Luminosity and High Energy

luminosity, operation, proton, cryogenics

2066

G. Papotti, M. Albert, R. Alemany-Fernandez, G.E. Crockford, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Lamont, D. Nisbet, L. Normann, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, M. Solfaroli Camillocci, R. Suykerbuyk, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland

In 2015 the Large Hadron Collider (LHC) entered the first year in its second long Run, after a 2-year shutdown that prepared it for high energy. The first two months of beam operation were dedicated to setting up the nominal cycle for proton-proton operation at 6.5 TeV/beam, and culminated with the first physics with 3 nominal bunches/ring at 13 TeV CoM on 3 June. The year continued with a stepwise intensity ramp up that allowed reaching 2244 bunches/ring for a peak luminosity of ~5·10³³ cm^-2s⁻¹ and a total of just above 4 fb-1 delivered to the high luminosity experiments. Beam operation was shaped by the high intensity effects, e.g. electron cloud and macroparticle-induced fast losses (UFOs), which on a few occasions caused the first beam induced quenches at high energy. This paper describes the operational experience with high intensity and high energy at the LHC, together with the issues that had to be tackled along the way.

Slides WEOCA01 [4.013 MB]

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WEOBB02

Status of Wakefield Monitor Experiments at the CLIC Test Facility

detector, pick-up, experiment, electron

2099

R.L. Lillestøl, E. Adli, J. Pfingstner
University of Oslo, Oslo, Norway
N. Aftab, S. Javeed
PINSTECH, Islamabad, Pakistan
R. Corsini, S. Döbert, W. Farabolini, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland

For the very low emittance beams in CLIC, it is vital to mitigate emittance growth which leads to reduced luminosity in the detectors. One factor that leads to emittance growth is transverse wakefields in the accelerating structures. In order to combat this the structures must be aligned with a precision of a few um. For achieving this tolerance, accelerating structures are equipped with wakefield monitors that measure higher-order dipole modes excited by the beam when offset from the structure axis. We report on such measurements, performed using prototype CLIC accelerating structures which are part of the module installed in the CLIC Test Facility 3 (CTF3) at CERN. Measurements with and without the drive beam that feeds rf power to the structures are compared. Improvements to the experimental setup are discussed, and finally remaining measurements that should be performed before the completion of the program are summarized.

Slides WEOBB02 [2.928 MB]

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WEIB06

Industry Role for Advanced Accelerator R&D

cavity, solenoid, plasma, linac

2114

R.P. Johnson
Muons, Inc, Illinois, USA

Besides large research institutes which typically focus on fundamental research, industrial companies can also contribute to the development of advanced applications of accelerators as well as to fundamental accelerator technology. The funding of advanced or fundamental R&D, which is usually high-risk but potentially high-reward, is difficult to obtain for any organization, especially smaller industrial companies. As an example of one funding approach, I discuss the role of industrial companies in the field of accelerators and present several examples from my own experience of advanced R&D performed by industry under the United States Department of Energy Small Business Innovation and Small Business Technology Transfer Research (SBIR-STTR) Grant programs.

Slides WEIB06 [6.226 MB]

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WEPMR012

Misalignment Studies of LCLS-II SC Linac

linac, network, alignment, cryomodule

2283

A. Saini, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a 4 GeV superconducting (SC) linear accelerator (linac). An optimal reliable performance of the linac is largely determined by beam sensitivity to various component alignment errors. In this paper we evaluate misalignment tolerances of LCLSII SC linac using a more realistic alignment model that includes correlated misalignment of elements.

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WEPMR047

Overall Design of Magnet Girder System for Heps-Tf

alignment, controls, photon, storage-ring

2383

H. Wang, L. Gong, C.H. Li, S. Li, H. Qu, Z. Wang, L. Wu
IHEP, Beijing, People's Republic of China

HEPS-TF is the test facility of HEPS (High Energy Pho-ton Source) of China. The magnet girders are used for supporting and positioning of the magnets. As the beam emittance is very low, the girder must has high adjusting precision and high stability. Besides, the girder should also be beam-based aligned. For these issues, two girder systems are designed. Both of them use cam mover mech-anisms for precision adjustment. One has six cam mover mechanisms and another has eight. The design aim of the alignment accuracy between girders is within 50 μm, and the adjusting resolution is within 3μm. The design aim of the natural frequency is above 30 Hz. This paper will discuss the scheme selection and structural design of the girder systems.

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WEPMW003

NONLINEAR OPTIMIZATION OF CLIC DRS NEW DESIGN WITH VARIABLE BENDS AND HIGH FIELD WIGGLERS

dipole, damping, dynamic-aperture, sextupole

2416

H. Ghasem, J. Alabau-Gonzalvo, F. Antoniou, S. Papadopoulou, Y. Papaphilippou
CERN, Geneva, Switzerland

The new design of CLIC damping rings is based on longitudinal variable bends and high field superconducting wiggler magnets. It provides an ultra-low horizontal normalised emittance of 412 nm-rad at 2.86 GeV. In this paper, nonlinear beam dynamics of the new design of the damping ring (DR) with trapezium field profile bending magnets have been investigated in detail. Effects of the misalignment errors have been studied in the closed orbit and dynamic aperture.

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WEPMW008

Possible Beam Parameters in Double RF Operation of the CERN LHC

operation, damping, synchrotron, SRF

2430

E.N. Shaposhnikova, J. F. Esteban Müller
CERN, Geneva, Switzerland

The LHC operates using a 400 MHz SC RF system. A 200 MHz NC RF system was foreseen in the LHC Design Report to improve beam capture and the bare resonators were manufactured, but never installed. Later the second harmonic RF system was proposed to cure longitudinal beam instabilities in the absence of a dedicated wideband feedback system in the LHC. For nominal intensities the longitudinal beam stability is ensured by controlled emittance blow-up during the acceleration ramp. Recently slow growing instabilities were observed at the end of long fills at 6.5 TeV as bunches shrink due to synchrotron radiation damping. For High Luminosity LHC twice higher intensities should be kept stable with new equipment installed in the ring. Additional motivations for a second RF system in the LHC have also been considered. Operation with an extra RF system is limited by the required RF configuration (phase between the two RF systems) and longitudinal beam stability. In this work requirements for the double RF systems are analyzed together with a possible range of longitudinal beam parameters.

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WEPMW009

Towards a Mono-chromatization Scheme for Direct Higgs Production at FCC-ee

luminosity, optics, collider, synchrotron

2434

M.A. Valdivia García, F. Zimmermann
CERN, Geneva, Switzerland
A. Faus-Golfe
IFIC, Valencia, Spain

Direct Higgs production in e⁺e⁻ collisions at the FCC is of interest if the centre-of-mass energy spread can be reduced by at least an order of magnitude. A mono-chromatization scheme, to accomplish this, can be realized with horizontal dispersion of opposite sign for the two colliding beams at the interaction point (IP). We review approaches from historical mono-chromatization studies, then derive a set of IP parameters which would provide the required performance in FCC e⁺e⁻ collisions at 63 GeV beam energy, compare these with the baseline optics parameters at neighbouring energies (45.6 and 80 GeV), comment on the effect of beamstrahlung, and, finally, discuss the modifications of the FCC-ee final-focus optics needed to obtain the required parameters.

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WEPMW010

Effect of Beamstrahlung on Bunch Length and Emittance in Future Circular e⁺e⁻ Colliders

radiation, photon, collider, synchrotron

2438

M.A. Valdivia García, F. Zimmermann
CERN, Geneva, Switzerland

In future circular e⁺e⁻ colliders, beamstrahlung may limit the beam lifetime at high energies, and increase the energy spread and bunch length at low energies. If the dispersion or slop of the dispersion is not zero at the collision point, beamstrahlung will also affect the transverse emittance. In this paper, we first examine the beamstrahlung properties, and show that for the proposed FCC-ee, the radiation is fairly well modelled by the classical formulae describing synchrotron radiation in bending magnets. We then derive a set of equations describing the equilibrium beam parameters in the presence of a nonzero dispersion at the collision point. An example case from FCC-ee will serve as an illustration.

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WEPMW011

Stable Spin Direction Investigations in RHIC

kicker, extraction, septum, injection

2442

F. Méot, H. Huang, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam and spin dynamics investigations are part of the preparations and studies regarding RHIC collider runs, they are part as well of the efforts dedicated to improving stored beam polarization, and in view of the eRHIC EIC project. Some recent studies and their outcomes are discussed.

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WEPMW013

Bunch Splitting Simulations for the JLEIC Ion Collider Ring

simulation, ion, collider, synchrotron

2448

B.R.P. Gamage, T. Satogata
ODU, Norfolk, Virginia, USA
T. Satogata
JLab, Newport News, Virginia, USA

We describe the bunch splitting strategies for the proposed JLEIC ion collider ring at Jefferson Lab. This complex requires an unprecedented 9:6832 bunch splitting, performed in several stages. We outline the problem and current results, optimized with ESME including general parameterization of 1:2 bunch splitting for JLEIC parameters.

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WEPMW014

Development of the Electron Cooling Simulation Program for JLEIC

electron, ion, collider, simulation

2451

H. Zhang, J. Chen, R. Li, Y. Zhang
JLab, Newport News, Virginia, USA
H. Huang, L. Luo
ODU, Norfolk, Virginia, USA

Funding: Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177
In the JLab Electron Ion Collider (JLEIC) project the traditional electron cooling technique is used to reduce the ion beam emittance at the booster ring, and to compensate the intrabeam scattering effect and maintain the ion beam emittance during collision at the collider ring. A new electron cooling process simulation program has been developed to fulfill the requirements of the JLEIC electron cooler design. The new program allows the users to calculate the electron cooling rate and simulate the cooling process with either DC or bunched electron beam to cool either coasting or bunched ion beam. It has been benchmarked with BETACOOL in aspect of accuracy and efficiency. In typical electron cooling process of JLEIC, the two programs agree very well and we have seen a significant improvement of computational speed using the new one. Being adaptive to the modern multicore hardware makes it possible to further enhance the efficiency for computationally intensive problems. The new program is being actively used in the electron cooling study and cooler design for JLEIC. We will present our models and some simulation results in this paper.

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WEPMW016

Towards a Small Emittance Design of the JLEIC Electron Collider Ring

dipole, electron, optics, damping

2457

F. Lin, Y.S. Derbenev, A. Hutton, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The electron collider ring of the Jefferson Lab Electron-Ion Collider (JLEIC) is designed to provide an electron beam with a small beam size at the IP for collisions with an ion beam in order to reach a desired high luminosity. For a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance that can be obtained through a linear optics design. This paper briefly describes the baseline design of the electron collider ring reusing PEP-II components and considering their parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and reports a few approaches to reducing the equilibrium emittance in the electron collider ring.

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WEPMW020

Storage-ring Electron Cooler for Relativistic Ion Beams

electron, damping, storage-ring, ion

2466

F. Lin, Y.S. Derbenev, D. Douglas, J. Guo, G.A. Krafft, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357
Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This paper reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the electron beam. The necessary energy difference is provided by an energy recovering SRF structure. A prototype linear optics of such storage-ring cooler is presented.

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WEPMW023

Higher Luminosity eRHIC Ring-Ring Options and Upgrade

electron, luminosity, quadrupole, linac

2472

R.B. Palmer, J.S. Berg, M. Blaskiewicz, A.V. Fedotov, C. Montag, B. Parker, H. Witte
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Lower risk ring-ring alternatives to the BNL linac-ling~[linacring] eRHIC electron ion collider (EIC) are discussed. The baseline from the Ring-Ring Working Group~[ringring] has a peak proton-electron luminosity of ≈§I{1.2e33}{cm^-2.s^-1}. An option has final focus quadrupoles starting immediately after the detector at 4.5~m, instead of at 32~m in the baseline. This allows the use of lower β^*s. It also uses more, 720, lower intensity, bunches, giving reduced IBS emittance growth and requiring only low energy pre-cooling. It has a peak luminosity of ≈§I{7e33}{cm^-2.s^-1}. An upgrade of this option, requiring magnetic, or coherent, electron cooling, has 1440 bunches and peak luminosity of ≈§I{15e33}{cm^-2.s^-1}.

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WEPMW028

First Attempts at using Active Halo Control at the LHC

simulation, controls, collimation, electron

2486

J.F. Wagner
Goethe Universität Frankfurt, Frankfurt am Main, Germany
R. Bruce, H. Garcia Morales, W. Höfle, G. Kotzian, R. Kwee-Hinzmann, A. Langner, A. Mereghetti, E. Quaranta, S. Redaelli, A. Rossi, B. Salvachua, R. Tomás, G. Valentino, D. Valuch, J.F. Wagner
CERN, Geneva, Switzerland
G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Research supported by the High Luminosity LHC project.
The beam halo population is a non-negligible factor for the performance of the LHC collimation system and the machine protection. In particular this could become crucial for aiming at stored beam energies of 700 MJ in the High Luminosity (HL-LHC) project, in order to avoid beam dumps caused by orbit jitter and to ensure safety during a crab cavity failure. Therefore several techniques to safely deplete the halo, i.e. active halo control, are under development. In a first attempt a novel way for safe halo depletion was tested with particle narrow-band excitation employing the LHC Transverse Damper (ADT). At an energy of 450 GeV a bunch selective beam tail scraping without affecting the core distribution was attempted. This paper presents the first measurement results, as well as a simple simulation to model the underlying dynamics.

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WEPMW044

Start-to-End Simulation of eRHIC ERL

linac, electron, simulation, synchrotron-radiation

2535

Y. Hao, S.J. Brooks, Y.C. Jing, F. Méot, V. Ptitsyn, D. Trbojevic, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The ERL-ring eRHIC adopts the electron accelerator design of a multi-pass energy recovery linac (ERL), with fixed field alternating gradient (FFAG) recirculating passes. To ensure the beam quality in the accelerating and decelerating stage and the energy recovery efficiency, detailed start-to-end simulation is required to evaluate the various beam dynamics effects, such as synchrotron radiation, wake fields, coherent synchrotron radiation. In this paper, we present the eRHIC ERL start-to-end simulation strategy with various simulation codes and the current status.

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WEPMY009

Transverse Tolerances of a Multi-Stage Plasma Wakefield Accelerator

plasma, simulation, linear-collider, acceleration

2561

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

Funding: This work is supported by the Research Council of Norway.
Plasma wakefield acceleration (PWFA) provides GeV/m-scale accelerating fields, ideal for applications such as a future linear collider. However, strong focusing fields imply that a transversely offset beam with an energy spread will experience emittance growth from the energy dependent betatron oscillation. We develop an analytic model for estimating tolerances from this effect, as well as an effective simplified simulation tool in Elegant. Estimations for a proposed 1 TeV PWFA linear collider scheme indicate tight tolerances of order 40 nm and 1 μrad in position and angle respectively.

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WEPMY013

A Spatially Separated Two Frequency RF Gun Design for Beam Brightness Improvement

gun, laser, cavity, brightness

2572

Z. Zhang, C.-X. Tang, Z. Zhang
TUB, Beijing, People's Republic of China
H.J. Qian
LBNL, Berkeley, California, USA

Recent theoretical and experimental studies shows that transverse beam brightness of photoinjector can be improved by cigar beam photoemission, and beam peak current are then increased with a RF buncher following the gun. We apply this concept to a S-band photoinjector by adding a harmonic RF buncher closely to a S-band RF gun, forming a compact spatially separated two frequency RF gun, targeting a 200 pC beam with emittance < 0.2 mm·mrad and 30 A peak current. Both S/X-band and S/C-band combinations are considered, and an optimized solution with 30 A peak current and 0.1 mm·mrad slice emittance are presented.

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WEPMY024

A Spectrometer for Proton Driven Plasma Accelerated Electrons at AWAKE - Recent Developments

plasma, electron, proton, simulation

2605

L.C. Deacon, S. Jolly, F. Keeble, M. Wing
UCL, London, United Kingdom
B. Biskup, A. Goldblatt, S. Mazzoni, A.V. Petrenko
CERN, Geneva, Switzerland
B. Biskup
Czech Technical University, Prague 6, Czech Republic
M. Wing
DESY, Hamburg, Germany
M. Wing
University of Hamburg, Hamburg, Germany

The AWAKE experiment is to be constructed at the CERN Neutrinos to Gran Sasso facility (CNGS). This will be the first experiment to demonstrate proton-driven plasma wakefield acceleration. The 400 GeV proton beam from the CERN SPS will excite a wakefield in a plasma cell several meters in length. To probe the plasma wakefield, electrons of 10–20 MeV will be injected into the wakefield following the head of the proton beam. Simulations indicate that electrons will be accelerated to GeV energies by the plasma wakefield. The AWAKE spectrometer is intended to measure both the peak energy and energy spread of these accelerated electrons. Results of beam tests of the scintillator screen output are presented, along with tests of the resolution of the proposed optical system. The results are used together with a BDSIM simulation of the spectrometer system to predict the spectrometer performance for a range of possible accelerated electron distributions.

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WEPMY033

Intermediate Commissioning Results of the 70 mA/50 keV H⁺ and 140 mA/100 keV D⁺ ECR Injector of IFMIF/LIPAC

rfq, operation, focusing, solenoid

2625

B. Bolzon, N. Chauvin, S. Chel, R. Gobin, F. Harrault, F. Senée, M. Valette
CEA/DSM/IRFU, France
J.M. Ayala, J. Knaster, A. Marqueta, K. Nishiyama, Y. Okumura, M. Perez, G. Pruneri, F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan
P.-Y. Beauvais, H. Dzitko, D. Gex, G. Phillips
F4E, Germany
L. Bellan
Univ. degli Studi di Padova, Padova, Italy
L. Bellan, M. Comunian, E. Fagotti, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P. Cara, R. Heidinger
Fusion for Energy, Garching, Germany
R. Ichimiya, A. Ihara, Y. Ikeda, A. Kasugai, T. Kikuchi, T. Kitano, M. Komata, K. Kondo, S. Maebara, S. O'hira, M. Sugimoto, H. Takahashi, H. Usami
JAEA, Aomori, Japan
K. Sakamoto
QST, Aomori, Japan
K. Shinto
Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan

The LIPAc accelerator aims to operate 125 mA/CW deuteron beam at 9 MeV to validate IFMIF's accelerators that will operate in CW 125 mA at 40 MeV. The different subsystems of LIPAc have been designed and constructed mainly by European labs and are being installed and commissioned in Rokkasho Fusion Center. The 2.45 GHz ECR injector developed by CEA-Saclay is designed to deliver 140 mA/100 keV CW D⁺ beam with 99% gas fraction ratio. Its LEBT presents a dual solenoid focusing system to transport and match the beam into the RFQ. Its commissioning continues in 2016 in parallel with the RFQ installation. The normalized RMS emittance at the RFQ injection cone is to be within 0.25π mm·mrad to allow 96% transmission through the 9.81 m long RFQ. In order to avoid activation during commissioning, an equal perveance H⁺ beam of half current and half energy as nominal with deuterons is used. In this article, the commissioning results with 110 mA/100 keV D⁺ beam and 55 mA/50 keV H⁺ beam are first reported.

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WEPOR052

Emittance Measurements in Low Energy Storage Rings

antiproton, simulation, electron, optics

2788

C.P. Welsch, J.R. Hunt, J. Resta-López
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under grant agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurements faces several challenges: non-zero dispersion and systematic errors due to diffusion processes, such as intra-beam scattering, and the speed of the scraper with respect to the beam revolution frequency. In addition, the beam distribution will likely be non-Gaussian. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA. We also discuss the feasibility of using alternative non-invasive techniques for profile and emittance measurements.

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WEPOR053

Software Tools for Emittance Measurement and Matching for 12 GeV CEBAF

quadrupole, GUI, optics, focusing

2792

D.L. Turner
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This poster discusses model-driven setup of the Continuous Electron Beam Accelerator Facility (CEBAF) for the 12 GeV era, focusing on qsUtility. qsUtility is a set of software tools created to perform emittance measurements, analyze those measurements, and compute optics corrections based upon the measurements. qsUtility was developed as a toolset to facilitate reducing machine configuration time and reproducibility by way of an accurate accelerator model, and to provide Operations staff with tools to measure and correct machine optics with little or no assistance from optics experts.

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WEPOW003

Design Considerations of a 7BA-6BA Lattice for the Future Upgrade of SOLEIL

dipole, lattice, optics, sextupole

2815

R. Nagaoka, P. Brunelle, H.C. Chao, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous studies indicated that adoption of a combination of 7 and 6BA cells in the existing SOLEIL ring enables reaching the target range of the horizontal emittance below 200 pm·rad as expected, in contrast to fewer dipole solutions such as a combination of 5 and 4BA studied earlier (IPAC 2014). However, the previous 7BA-6BA lattice resulted in having unacceptably strong gradients in quadrupoles and dipoles leading to high natural chromaticities. Several schemes that would allow for an improvement are explored, such as shortening the insertion device straight sections by one or two meters to create more space for the magnetic structure, lowering the dipole fields and the use of anti-bends as proposed by A. Streun. The effectiveness of each scheme is evaluated and the best combined use of them for SOLEIL is investigated. Ways to fulfil the constraints of the existing dipole beam lines are studied by introducing longitudinal gradient bends and/or multipole wigglers. The nonlinear optimisation to maximise the on and off-momentum apertures is made by using genetic algorithm-based numerical codes. A comparison of their performance and the obtained results are presented.

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WEPOW006

Hybrid Multi Bend Achromat at 3 GeV for Future 4th Generation Light Sources

lattice, sextupole, dynamic-aperture, dipole

2822

S.M. Liuzzo, D. Einfeld, L. Farvacque, P. Raimondi
ESRF, Grenoble, France

Starting from the Hybrid Multi Bend Achromat (HMBA) lattice designed for the 6GeV ESRF-EBS we rescale the lattice energy to 3GeV and optimize the lattice parameters to achieve dynamic apertures sufficient for injection and lifetimes of more than 7h without errors. The rescaling results to an emittance of roughly 140pmrad. Further optimizations of bending magnets longitudinal gradient, optics and sextupole fields show the possibility to further decrease emittance and increase the DA and lifetime. A comparison with other lattice designs is also presented.

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WEPOW008

Specific Operation Modes at the Metrology Light Source

operation, electron, radiation, cavity

2829

J. Feikes, P. Goslawski, J. Li, M. Ries, M. Ruprecht, G. Wüstefeld
HZB, Berlin, Germany
A. Hoehl
PTB, Berlin, Germany

The high flexibility of the Metrology Light Source (MLS) allows application of various nonstandard user modes adapted to the specific needs of their users. We report on some of them including a mode for division of the revolution frequency for the user signal and a mode with an adjustable photon pulse delay on the few ps scale.

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WEPOW010

Beam Lifetime Optimization by Adjusting the Sextupoles at the MLS and BESSY

sextupole, storage-ring, radiation, operation

2837

J. Li, J. Feikes, P. Goslawski, M. Ries, M. Ruprecht, T. Tydecks
HZB, Berlin, Germany

The Metrology Light Source (MLS) is a dedicated elec-tron storage ring for metrology applications with three families of sextupoles. The existing setting of the three independently powered sextupole families respective to lifetime were roughly determined by scanning their strengths against each other. As a flexible machine the sextupole families of the MLS can be regrouped into new families, which increase the complexity of the scan pro-cedure. Consequently the former strategy would be too time-consuming for refined global scan and it has to be complemented with physical constraints. Therefore a scheme has been developed to keep the chromaticity in a reasonable range during the scan and to reduce the degree of freedom, which is even more important at BESSY II with increasing number of independent sextupole cir-cuits. This paper presents the principle of sextupole scan and the experimental results at the MLS and preliminary test at BESSY II.

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WEPOW016

Designing an Ultra Low Emittance Lattices for Iranian Light Source Facility Storage Ring

lattice, storage-ring, vacuum, scattering

2858

E. Ahmadi, M. Jafarzadeh, J. Rahighi
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran
S.M. Jazayeri
IUST, Narmac, Tehran, Iran

Electron storage rings are extensively used for high luminosity colliders, damping rings in high-energy physics and synchrotron light sources. To further increase the luminosity at the colliders or brightness of a synchrotron light sources, the beam emittance is being continually pushed downward. In this paper, we investigate the lattice design for the storage ring of Iranian Light Source Facility (ILSF) with an ultra-low emittance, intermediate energy of 3 GeV and circumference of 528 m. We present the design results for a five-band achromat lattice with the natural emittance of 276 pm-rad. The base line is based on 20 straight sections with the length of 7 m.

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WEPOW018

Elettra Status and Upgrades

operation, insertion, insertion-device, wiggler

2864

E. Karantzoulis, A. Carniel, S. Krecic, C. P. Pasotti
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with the possible future upgrades especially concerning the next ultra low emittance light source Elettra2.0.

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WEPOW019

SPring-8 Upgrade Project

undulator, operation, laser, radiation

2867

H. Tanaka, T. Ishikawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Goto, S. Takano, T. Watanabe, M. Yabashi
JASRI/SPring-8, Hyogo, Japan

Plans are underway for the upgrade of the SPring-8 facility, targeting completion in the early 2020's. Sustainability is a key guiding principle for the fourth-generation X-ray source - a beam emittance of around 100 pm.rad is pursued simultaneously with substantial energy-saving. The three key features of the design are (i) to replace the main dipole electric magnets with permanent magnets, (ii) to reduce the electron beam energy from 8 to 6 GeV, and (iii) to use the SACLA linac as an injector. Lowering the beam energy leads to reduction of (a) beam emittance, (b) magnetic fields, (c) the lengths of ID straight sections to maintain larger spaces for the magnets, and (d) the RF power consumption. Timeshare use of the SACLA linac enables beam injection to the upgraded ring with a low-emittance and short-pulsed beam as well as a reduction of injector power consumption by stopping the present injector consisting of a 1-GeV linac and a booster synchrotron. The outline of the upgrade plan will be reported with the current status of R&D started in 2015.

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WEPOW020

Present Status of KEK Photon Factory and Future Project

undulator, lattice, storage-ring, operation

2871

T. Honda, M. Adachi, S. Asaoka, K. Haga, K. Harada, Y. Honda, X.J. Jin, T. Kageyama, R. Kato, Y. Kobayashi, K. Marutsuka, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, M. Ono, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, O. Tanaka, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, N. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
KEK, Ibaraki, Japan

Two synchrotron radiation sources of KEK, the PF-ring and the PF-AR, continue their user operation with various improvements. Scrap and build of the first generation undulators of 1980s at the PF-ring is pushed forward year by year. Five new elliptically polarized undulators have been installed in these five years, and we have also installed four very narrow-gap short-period undulators generating high brilliant X-ray. The new beam transport line that enables the 6.5-GeV full energy injection for PF-AR will be completed by the end of 2016 in order to make the top-up operation of the two SR sources compatible with the continuous injection for two main rings of the Super-KEKB. We have proposed a project of further upgrade of the 2.5-GeV PF-ring to improve its horizontal emittance as 8 nm rad using combined bending magnets at the arc sections. And we are also moving ahead on proposal of constructing a new KEK light source of an extremely low emittance as 0.3 nm rad. The progress and detail of our future project will be described in this paper.

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WEPOW021

The Low Emittance Reconstruction of the Arc Section of the Photon Factory

dynamic-aperture, photon, sextupole, lattice

2874

K. Harada, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka
KEK, Ibaraki, Japan

The present horizontal emittance of the Photon Factory (PF) ring is about 35.4 nmrad. By the reconstruction of the normal cells at the arc section, the emittance can be reduced to about 8 nmrad. The double number of the combined function short bending magnets are adopted and one present normal cell become two new normal cells. Although the lattice of the straight sections are not changed, the optics are optimized to reduce the non-linear effects of the sextupoles of the arc sections. By keeping the tune advance of the straight section as 3 for the horizontal direction and 2.5 for the vertical, the dynamic aperture as large as that of the present ring can be achieved with the magnetic errors. The difference of the optics of the straight sections are so little that the beam injection and the operation of the in-vacuum short-gap undulators can be maintained. The hardware design will be began as the next step for the realization of the plan. In this proceedings, the design, optimization and simulation results for the low emittance lattice are shown.

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WEPOW025

Exploring the Ultimate Linear and Nonlinear Performance of the HEPS hybrid 7BA design

sextupole, lattice, storage-ring, optics

2883

Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS), a kilometre- scale diffraction-limited storage ring (DLSR) light source, with a beam energy of 5 to 6 GeV and transverse emittances of a few tens of pm.rad, is to be built in Beijing. We have obtained a hybrid 7BA lattice design, with a natural emittance of about 60 pm.rad and a circumference of about 1.3 kilometres, basically satisfying the requirement of on-axis longitudinal injection in HEPS. Nevertheless, it is interesting and necessary to explore the ultimate linear and nonlinear performance of the HEPS hybrid 7BA design. In this paper, we will introduce the multi-objective optimization with a successive and iterative implementation of the MOPSO and MOGA algorithms, and discuss certain relations between the nonlinear dynamics and linear optics of a hybrid MBA lattice. This study can provide reference for other DLSR lattice design and optimizations.

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WEPOW026

Recent Physical Studies for the HEPS Project

injection, lattice, booster, sextupole

2886

G. Xu, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, X.Y. Li, Y.M. Peng, Q. Qin, J. Qiu, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, C.H. Yu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS), a kilometre- scale storage ring light source, with a beam energy of 5 to 6 GeV and transverse emittances of a few tens of pm.rad, is to be built in Beijing and now is under design. In this paper we reported the progress and status of the physical studies for the HEPS project, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, longitudinal dynamics, etc.

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WEPOW027

Initial Lattice Design for Hefei Advanced Light Source: A VUV and Soft X-ray Diffraction-limited Storage Ring

lattice, sextupole, storage-ring, quadrupole

2889

Z.H. Bai, Q.K. Jia, W. Li, G. Liu, C.W. Luo, Q. Luo, L. Wang
USTC/NSRL, Hefei, Anhui, People's Republic of China

The upgrade project of Hefei Light Source was successfully completed in 2014 and has been operated for synchrotron radiation users since 2015, which is a second generation light source in the range of VUV and soft X-ray at NSRL in China. To meet the future requirements for users, more efforts are now putting at NSRL into the design of Hefei Advanced Light Source (HALS), a new VUV and soft-X ray diffraction-limited storage ring. The HALS storage ring will have an energy of 2 GeV and a natural emittance of about 50 pm·rad. This paper reports the initial lattice design studies, including linear optics design and nonlinear dynamics optimization.

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WEPOW034

Emittance Diagnostics at the Max Iv 3 Gev Storage Ring

dipole, radiation, electron, diagnostics

2908

J. Breunlin, Å. Andersson
MAX IV Laboratory, Lund University, Lund, Sweden

With the MAX IV project in Lund, Sweden an ultralow emittance storage ring light source is going into user operation in 2016. Due to its multibend achromat lattice design the 3 GeV storage ring reaches a horizontal emittance lower than 330 pm rad. Emittance diagnostic will involve two diagnostic beamlines to image the electron beam with infrared and ultraviolet synchrotron radiation from bending dipoles. Placed in locations of different optic functions the beamlines will provide experimental access to both horizontal and vertical emittance and to beam energy spread. Since bunch lengthening with harmonic cavities is essential for machine performance, time resolved measurements with synchrotron radiation for individual longitudinal bunch distributions are of special interest as well.

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WEPOW038

Proposed Upgrade of the SLS Storage Ring

lattice, storage-ring, sextupole, optics

2922

A. Streun, M. Aiba, M. Böge, C. Calzolaio, M.P. Ehrlichman, A. Müller, A. Saá Hernández, H.S. Xu
PSI, Villigen PSI, Switzerland

A new storage ring is planned for the upgrade of the Swiss Light Source (SLS). It will replace the 12 triple bend achromats by twelve 7-bend achromats, which are based on low aperture longitudinal gradient bends (LGBs) and anti-bends (ABs), thus reducing the emittance from 5.0 nm to about 150 pm at 2.4 GeV while maintaining the source points of the undulator based beam lines. Sextupole and octupole strengths are determined using a multi-objective genetic algorithm (MOGA) and result in sufficient dynamic aperture for off-axis injection and several hours of Touschek lifetime. Superconducting LGBs of 5-6 T peak field will extend the photon range of the SLS up to 80-100 keV. The vacuum system will be based on a 20 mm inner diameter copper beam pipe with ante-chamber, and discrete getter pumps. It is planned to reuse the existing injector complex and the dynamically adjustable girder system.

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WEPOW045

Concepts for a Low Emittance-High Capacity Storage Ring for the Diamond Light Source

lattice, photon, wiggler, dipole

2943

R. Bartolini, G. Cinque, G. Evans, K. Sawhney, J. Zegenhagen
DLS, Oxfordshire, United Kingdom

The Diamond Light Source is investigating several paths for a possible machine upgrade to Diamond II. The exercise is driven by by a joint assessment of the science capabilities opened by a very low emittance ring and the machine design that will underpin them. The consultation is made on a beamline-by-beamline basis and has highlighted a significant preference for lattices that combine both a low emittance and large capacity for IDs.

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WEPOW049

Physics Design Progress towards a Diffraction Limited Upgrade of the ALS

lattice, injection, brightness, dynamic-aperture

2956

C. Steier, J.M. Byrd, S. De Santis, H. Nishimura, D. Robin, F. Sannibale, C. Sun, M. Venturini, W. Wan
LBNL, Berkeley, California, USA

Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of more than two orders of magnitude are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source. We will describe the progress in the physics design of this upgrade, including lattice evolution, error tolerance studies, simulations of collective effects, and intra beam scattering.

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WEPOW050

Optimization of the ALS-U Storage Ring Lattice

lattice, storage-ring, quadrupole, injection

2959

C. Sun, H. Nishimura, D. Robin, F. Sannibale, C. Steier, M. Venturini, W. Wan
LBNL, Berkeley, California, USA

Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory is proposing the upgrade of its synchrotron light source to reach soft x-ray diffraction limits within the present ALS footprint. The storage ring lattice design and optimization of this light source is one of the challenging aspects for this proposed upgrade. The candidate upgrade lattice needs not only to fulfill the physics design requirements such as brightness, injection efficiency and beam lifetime, but also to meet engineering constraints such as space limitations, maximum magnet strength as well as beamline port locations. In this paper, we will present the approach that we applied to design and optimize a multi-bend achromat based storage ring lattice for the proposed ALS upgrade.

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WEPOW051

R+D Progress Towards a Diffraction Limited Upgrade of the ALS

vacuum, injection, undulator, storage-ring

2962

C. Steier, A. Anders, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, H. Nishimura, T. Oliver, J.R. Osborn, H.A. Padmore, G.C. Pappas, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan, Y. Yang
LBNL, Berkeley, California, USA

Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings. It involves many areas, and focuses on the specific needs of soft x-ray facilities: NEG coating of small chambers, swap-out injection, bunch lengthening, magnets/radiation production, x-ray optics, and beam physics design optimization. Hardware prototypes have been built and concepts and equipment was tested in beam tests on the existing ALS.

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WEPOY009

Simulation Study of Emittance Growth from Coulomb Explosion in a Charge Separator System After Stripping

electron, space-charge, simulation, ion

3005

M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: BMBF-05P15RFRBA
A computer 3D particle-in-cell (PIC) simulation is used to examine the emittance growth of an intense heavy ion beam after a charge stripper. Multi-species dynamics of the bunched uranium beam with various charge states and including compensation electrons will be presented. The rms-emittance growth shows different behaviour in the horizontal, vertical and longitudinal planes, dependent on initial conditions, like a bunch size, beam current and phase space ellipse orientation. An optimization of initial parameters is therefore crucial for a successful and efficient post-acceleration. The role of the separation system and of co-moving electrons will be discussed for the example of the GSI-Unilac.

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WEPOY016

Use of Nonuniform Magnets for Emittance Reduction

lattice, dipole, simulation, radiation

3014

E.B. Levichev, G.N. Baranov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

We study a theoretical minimum emittance (TME) for a non-uniform bending magnet including a three-step bend (sandwich magnet), a dipole with linear ramp of the bend-ing radius and the same but with a central segment of constant field. We derive expression for the minimum emittance and expand it into a power series with respect to the bending angle. A zero-order term naturally gives the uniform magnet TME while higher-order terms are responsible for the emittance reduction. Theoretical re-sults are verified by numerical simulation.

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WEPOY018

Study on Electron Beam Transverse Emittance at the Linac-based THz Laboratory in Thailand

quadrupole, electron, simulation, linac

3017

K. Kosaentor
IST, Chiang Mai, Thailand
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand

This research focuses on simulation of transverse emittance of electron beams, which are produced from a thermionic RF-gun at the Plasma and Beam Physics (PBP) Research Facility, Chiang Mai University (CMU). The RF-gun is used to together with an alpha magnet for serving as the electron injector system for the PBP linac-based THz source. The quadrupole scan technique is utilized to measure the transverse beam emittance at the entrance of the alpha magnet. The experimental setup consists of quadrupole magnets with a maximum gradient of 7.01 T/m, a drift tube, and a movable fluorescent screen station. Beam dynamic simulations by using the computer codes PARMELA and ELEGANTare performed to track electrons from the cathode to the experimental station. In this contribution, the emittance values from simulations including the space charge effects will be reported.
This work has been supported by the CMU Junior Research Fellowship Program, Department of Physics and Material Science, Faculty of science, Chiang Mai University.

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WEPOY019

Beam Optimization Study for an X-ray FEL Oscillator at the LCLS-II

flattop, electron, FEL, linac

3020

W. Qin, S. Huang, K.X. Liu
PKU, Beijing, People's Republic of China
K.L.F. Bane, Y. Ding, Z. Huang, T.J. Maxwell
SLAC, Menlo Park, California, USA
K.-J. Kim, R.R. Lindberg
ANL, Argonne, Ilinois, USA

The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.
* T. J. Maxwell et al., Feasibility study for an X-ray FEL oscillator at the LCLS-II, IPAC15, TUPMA028.

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WEPOY023

Beam Dynamics Studies for Coherent Electron Cooling Experiment

electron, linac, SRF, cavity

3032

Y.H. Wu, D. Kayran, V. Litvinenko, I. Pinayev
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron Cooling (CeC)* is a proposed advanced beam cooling method that has the potential to reduce the ion beam emittance in significantly shorter time compared to existing cooling methods. The newly constructed linear electron accelerator for the CeC experiment can generate electron beams with the required beam parameters for effective cooling. In this paper, we show simulation studies for the CEC linac by using the PARMELA** and ELEGANT*** beam dynamics tracking codes.
* V.N.Litvinenko and Y.S.Derbenev, PRL 102, 114801 (2009)
** Lloyd M.Young, Parmela manual, Los Alamos National Laboratory
*** M. Borland, Elegant, Argonne National Laboratory (2000)

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WEPOY024

Beam Dynamics Simulations of the Thomx Linac

gun, solenoid, laser, electron

3036

L. Garolfi, C. Bruni, M. El Khaldi, P. Lepercq, C. Vallerand
LAL, Orsay, France
N. Faure
PMB-ALCEN, PEYNIER, France

ThomX Compton light source is designed to maximise the average X-ray flux providing a compact and tunable machine which can operate in hospitals or in museums. These constraints impose the choice of a high collision rate which is based on S-band Linac whose energy is 50-70 MeV combined to an electron storage ring. As most of the performances of the electron beam at the interaction point depend on the beam quality at the ring entrance, the linear accelerator must be carefully designed and especially the photo-injector. Simulations have been carried out in order to optimise the emittance for the ring entrance. Indeed, for a bunch charge of 1 nC, space charge effects usually dominate the total beam emittance. The latter can be minimized at the end of the Linac by means of emittance compensation. The best configuration across all the parameters will be presented.

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WEPOY057

The 2015 eRHIC Ring-Ring Design

electron, proton, luminosity, polarization

3126

C. Montag, E.C. Aschenauer, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, J.M. Brennan, A.V. Fedotov, W. Fischer, V. Litvinenko, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, S. Tepikian, D. Trbojevic, F.J. Willeke
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.
To reduce the technical risk of the future electron-ion collider eRHIC currently under study at BNL, the ring-ring scheme has been revisited over the summer of 2015. The goal of this study was a design that covers the full center-of-mass energy range from 32 to 141 GeV with an initial luminosity around 10³³ cm^-2 sec^-1, upgradeable to 10³⁴ cm^-2 sec^-1 later on. In this presentation the baseline design will be presented, and future upgrades will be discussed.

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THYA01

Advanced Concepts and Methods for Very High Intensity Linacs

space-charge, diagnostics, focusing, simulation

3155

P.A.P. Nghiem, N. Chauvin, D. Uriot
CEA/DSM/IRFU, France
M. Comunian
INFN/LNL, Legnaro (PD), Italy
C. Oliver
CIEMAT, Madrid, Spain
W. Simeoni
IF-UFRGS, Porto Alegre, Brazil
M. Valette
CERN, Geneva, Switzerland

For very high intensity linacs, both beam power and space charge should be taken into consideration for any analysis of accelerators aiming at comparing their performances and pointing out the challenging sections. As high beam power is an issue from the lowest energy, careful and exhaustive beam loss predictions have to be done. High space charge implies lattice compactness making the implementation of beam diagnostics very problematic, so a clear strategy for beam diagnostic has to be defined. Beam halo becomes no longer negligible, and it plays a significant role in the particle loss process. Therefore, beam optimization must take the halo into account and beam characterization must be able to describe the halo part in addition to the core one. This presentation discusses advanced concepts and methods for beam analysis, beam loss prediction, beam optimization, beam diagnostic and beam characterization especially dedicated to very high intensity accelerators.

Slides THYA01 [6.177 MB]

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THOBA02

Space Charge Induced Collective Modes and Beam Halo in Periodic Channels

space-charge, focusing, resonance, simulation

3165

C. Li, Zh.C. Liu, Q. Qin, Y.L. Zhao
IHEP, Beijing, People's Republic of China

Funding: This work is supported by the Ministry of Science and Technology of China under Grant No. 2014CB845501.
The collective mode instabilities of periodically focused high intensity beams based on the Vlasov-Poisson equation are investigated both analytically and numerically. It is found that the broadened collective stop bands resulting from space charge induced structure resonance in long periodic channels predict well the areas where the rms emittance growth accompanied with n-fold phase space structure (beam halo) would take place. We believe that the formed beam halo, which is depicted in action-angle frame, could be understood as a side-effect of the collective beam mode.

Slides THOBA02 [4.704 MB]

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THOAB03

Ultrafast Electron Microscopy using 100 Femtosecond Relativistic-Energy Electron Beam

electron, gun, brightness, laser

3183

J. Yang, K. Kan, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

An ultrafast detection technique on 100 fs time scales over sub-nanometer (even atomic) spatial dimensions has long been a goal for the scientists to reveal and understand the ultrafast structural-change induced dynamics in materials. In this paper, the generation of femtosecond electron pulses using the RF gun and the first prototype of femtosecond time-resolved relativistic-energy ultrafast electron microscopy (UEM) are reported. Finally, both relativistic-energy electron diffraction and image measurements in the UEM prototype are presented.

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THPMB006

Unclosed Lattice Dispersions as a Tool for Partial Removal of Transverse to Longitudinal Beam Correlations

lattice, coupling, synchrotron, optics

3229

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

We show how to choose unclosed lattice dispersions in order to zero either linear beam dispersions (linear correlations between energy of particles and their transverse positions and momenta) or linear beam tilts (linear correlations between longitudinal positions of particles and their transverse coordinates). Besides that, we prove that while removal of beam dispersions always leads to reduction of transverse projected emittances, zeroing of beam tilts cannot guarantee it.

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THPMB010

Dogleg Design for the SINBAD Linac

electron, acceleration, dipole, linac

3244

J. Zhu, R.W. Aßmann, U. Dorda, B. Marchetti
DESY, Hamburg, Germany
R. Rossmanith
KIT, Karlsruhe, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to provide sub-fs to tens of fs electron bunches for the R&D of novel acceleration concepts and applications, e.g. Laser Wake-Field Acceleration (LWFA), Dielectric Laser Acceleration (DLA) and medical imaging. We present the design study of the dogleg at the SINBAD linac, which is capable of delivering ultra-short bunches to the second beamline. The longitudinal dispersion of the dogleg can be finely tuned so that it can either transport the ultra-short bunch produced upstream by velocity bunching, or compress the incoming long bunch. The achievable beam parameters are investigated by start-to-end simulations.

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THPMB012

The HMBA Lattice Optimization for the New 3 GeV Light Source

lattice, brightness, storage-ring, injection

3251

K. Harada, M. Adachi, N. Funamori, T. Honda, Y. Kobayashi, N. Nakamura, K. Oide, H. Sakai, S. Sakanaka, K. Tsuchiya
KEK, Ibaraki, Japan

For the design study of the HMBA (hybrid multi bend achromat) type most advanced light source, the new storage ring was designed from the lattice of the phase II upgrade project of the ESRF (ESRF II). Although the original 3 GeV test lattice from Dr. Pantaleo Raimondi of ESRF has no problem about the optical and magnetic parameters including the dynamic aperture, we reduce the cell numbers and inserted the short straight sections for the in-vacuum short-gap undulators. After the optimization of the linear and non-linear optics as the original design principle of ESRF II, the altered lattice has the circumference of about 440 m with 16 HMBA cells, the emittance about 440 pm rad with the intra-beam scattering effect at the beam current of 500 mA, and the large dynamic aperture of about 2 cm at the injection point even with the usual magnetic errors.

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THPMB015

Muon Charge Separation by Mixed Structure of Dipoles and Solenoids

solenoid, dipole, target, beam-transport

3257

Y.P. Song, H.T. Jing, J.Y. Tang
IHEP, Beijing, People's Republic of China

A charge separation system comprised by dipoles and solenoids is described which aims to separate positive particles and negative particles apart in secondary beam with a large emittance and huge momentum spread, particularly for mixed-charge muon beams. Nonlinear effect and fringe field effect due to large aperture and large moment range are crucial under this circumstance, which make the charge separation extremely complicated. The design schemes by dipoles and bent solenoids and also simulation results are showed in the paper.

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THPMB017

The Errors Study on a Recent Heps Low-Beta Design

lattice, optics, sextupole, quadrupole

3260

D. Ji, Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

The next synchrotron light source High Energy Photon Source is currently studied at Beijing. A nominal design for the HEPS, in a hybrid 7BA lattice and with an emittance of 60 pm.rad in a circumference of 1.3 kilometers, is completed for further study. In this paper, we present some work on error effect based on the nominal lattice design. Topics covered include dynamic aperture and beam parameters affected by magnetic field error, systematic and random multipole errors and misalignment effect.

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THPMB018

Candidate Booster Design for the HEPS Project

booster, sextupole, lattice, injection

3263

Y.M. Peng, Y.Y. Guo, Y. Jiao, Y. Wei, G. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS), with trans-verse emittances of a few tens of pm.rad, is to be built in the suburbs of Beijing, China. The HEPS booster is a 2 Hz electron synchrotron. It accelerates electron bunches from a 300 MeV linac to a final energy of 6 GeV, and then extracts and injects them into the stor-age ring. We have made a candidate booster design, with a circumference of about 432 m and a natural emittance of about 4 nm.rad at 6GeV, which will be located in a separate tunnel. This lattice has a four-fold symmetry. Each super-period is composed of 13 iden-tical cells and two matching cells. The lattice design and optimization and other considerations are present-ed in a detail.

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THPMB019

Comparing the Performance of MOGA and MOPSO in Optimization of the HEPS Performance

sextupole, lattice, quadrupole, storage-ring

3266

Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS), a kilometre- scale diffraction-limited storage ring light source, with a beam energy of 5 to 6 GeV and emittances of a few tens of pm.rad, is to be built in Beijing. A preliminary design with a hybrid 7BA lattice, an emittance of 60 pm.rad and a circumference of about 1.3 kilometers, has been made. Based on this design, we optimized the linear and nonlinear performance of the ring with the MOGA and MOPSO algorithms. From comparison of the performance of these two algorithms, it was found that MOPSO promises higher diversity than MOGA, while MOGA can reach better convergence than MOPSO. To reach a true Pareto front, a successive and iterative implementation of the PSO and MOGA, rather than using either of these two algorithms, is suggested.

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THPMB024

Error Analysis for the Lattice of FELiChEM

FEL, undulator, simulation, lattice

3278

S. Huang, Z.G. He, W. Xu, S.C. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC).The facility consists of the middle-infrared (MID-FEL) beam line for 2.5-50 um and the Far-infrared (FAR-FEL) beam line for 40-200um. To achieve the design FEL performance of IR-FEL, the beam with 30 mm-mrad emittance, 5 ps rms length and 1nC bunch charge is required. We conduct error analysis in order to evaluate the tolerances of machine parameters and alignments. In this paper, we simulate the orbit corrections and emittance growth under exist of misalignments and strength errors of magnets. The simulation results show that the trajectory errors can be corrected to mm levels in the whole lattice and the emittance increase is acceptable. At the entrance of undulator, the position and angular errors can be corrected very well. So the trajectory can be controlled in the undulator to meet the requirement of FEL.

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THPMB029

Simultaneous Two Beam Acceleration Lattice Design Study for the Post Linear Accelerator of RISP

lattice, ion, acceleration, simulation

3294

S.W. Jang
KNU, Deagu, Republic of Korea
E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea

The Rare Isotope Science Project, RISP, is the research complex by using heavy ion accelerator, which RISP research complex consists of front-end system, super conducting linear accelerator(SCL), ISOL system, In-fight system. The original purpose of post linear accelerator was for the alternative acceleration of stable driver beam from ECR ion source and unstable rare isotope beam from ISOL system. The new concept of acceleration method by using post accelerator lattice was studied to get more benefits. The idea was the simultaneous acceleration of stable driver beam and RI beam by using the average A/q value of post accelerator lattice. For the simultaneous two beam acceleration study, we used two ion beams the first one was 58Ni+8 and the other one was 132Sn+20. The beam dynamics simulation was performed by TRACK and TraceWin codes. In this poster, we will describe the results of beam dynamics study for the simultaneous two beam acceleration of the post linear accelerator of RISP.

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THPMB032

Design Study and Multi-particle Tracking Simulation of the IH-DTL with KONUS Beam Dynamics for KHIMA Project

DTL, simulation, quadrupole, acceleration

3299

Y. Lee, E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea
G. Hahn
KIRAMS, Seoul, Republic of Korea
Z. Li
SCU, Chengdu, People's Republic of China

The Korea Heavy Ion Medical Accelerator (KHIMA) project of the Korea Institute of Radiological and Medical Sciences (KIRAMS) has developed heavy ion medical accelerator. The injector system of the accelerator for the KHIMA project is composed of a low energy beam transport line (LEBT), radio frequency quadrupole (RFQ), interdigit H-mode drift tube linac (IH-DTL), and medium energy beam transport line (MEBT). The IH-DTL is designed with KONUS beam dynamics, and KONUS indicates a combined 0˚ structure. Optimization aims are to increase the quality of the beam and to reduce the beam loss. KONUS beam dynamics design and multi-particle tracking simulations of the IH-DTL with LORASR and TraceWIN code are performed.

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THPMB034

Short Bunch Operation Mode Development at the Synchrotron Radiation Source Siberia-2

operation, optics, synchrotron, synchrotron-radiation

3305

Y.A. Fomin, V. Korchuganov, S.I. Tomin, A.G. Valentinov
NRC, Moscow, Russia

Decrease of the electron bunch length gives rise to coherent synchrotron radiation in the THz spectral region. Also, the short photons pulse could provide an option for time-resolved processes studies. Currently the possibility to operate with short electron bunch of the synchrotron radiation source Siberia-2 is under consideration for this purpose. In the report the techniques of electron bunch shortening are described as well as the requirements are given for the parameters of the electron bunch and lattice. The authors present a modified lattice for the synchrotron radiation source Siberia-2 with low momentum compaction factor and the results of the beam dynamics studies.

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THPMB035

A Comparative Study of Low Energy Compact Storage Rings for a Thomson Scattering X-ray Source

storage-ring, scattering, lattice, dynamic-aperture

3308

L. Ovchinnikova, V.I. Shvedunov
SINP MSU, Moscow, Russia
E.G. Bessonov, M.V. Gorbunkov
LPI, Moscow, Russia
A.A. Mikhailichenko
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.I. Shvedunov
LEA MSU, Moscow, Russia

A low-energy (<50 MeV) compact storage ring is a basic component of an X-ray source with high average flux based on Thomson scattering. Such ring provides electron bunches with ~1 nC charge and repetition rate up to 100 MHz for interaction with intense laser pulses. Such ring should provide a small (tens of microns rms) beam radius at interaction point, must have large dynamic aperture, sufficient space for allocation of different elements, such as laser resonator, RF cavity, fast beam injection/extraction systems, beam pick-ups and correctors. In this report, we present the results of comparative study of four versions of storage ring with different structure of lattices.

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THPMB039

Voltage Error Studies in the ESS RFQ

rfq, proton, linac, radio-frequency

3320

A. Ponton, Y.I. Levinsen, E. Sargsyan
ESS, Lund, Sweden
A.C. France, O. Piquet, B. Pottin
CEA/IRFU, Gif-sur-Yvette, France

During the fabrication of an RFQ, deviation from the perfect geometry will occur during assembling, brazing and machining the different parts. These geometrical defects will impact the theoretical inter-vane voltage, given by the beam dynamics, by altering the quadrupolar component as well as adding dipolar terms in the voltage function. Tuners can correct partially the effect of the manufacturing. The study summarizes the effects of the voltage errors on the beam quality in the case of the ESS RFQ with a harmonic analysis of the voltage function. We discuss the acceptable level of voltage errors and associated mechanical tolerances.

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THPMB040

Charged Particle Transport, Gaussian Optics, Error Propagation: It's all the Same

optics, laser, beam-transport, electron

3324

V.G. Ziemann
Uppsala University, Uppsala, Sweden

We derive a correspondence between the parameters used in Gaussian light beam propagation with wavelength, beam size, and wave front curvature to the description in terms of emittance and Twiss parameters commonly used in charged particle optics. Furthermore, we discuss the analogy of transporting beams to the propagation of measurement uncertainties.

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THPMB043

Progress in Ultra-Low β* Study at ATF2

optics, operation, linear-collider, extraction

3335

M. Patecki, D.R. Bett, F. Plassard, R. Tomás
CERN, Geneva, Switzerland
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
M. Patecki
Warsaw University of Technology, Warsaw, Poland
T. Tauchi, N. Terunuma
Sokendai, Ibaraki, Japan

A nanometer beam size in the interaction point (IP) is required in case of future linear colliders for achieving the desired rate of particle collisions. KEK Accelerator Test Facility (ATF2), a scaled down implementation of the beam delivery system (BDS), serves for investigating the limits of electron beam focusing at the interaction point. The goal of the ultra-low beta∗ study is to lower the IP vertical beam size by lowering the beta_y∗ value while keeping the beta_x∗ value unchanged. Good control over the beam optics is therefore required. The first experience with low beta∗ optics revealed a mismatch between the optics designed in the model with respect to the beam parameters observed in the experiment. Additionally, existing methods of beam parameters characterization at the IP were biased with high uncertainties making it difficult to set the desired optics. In this paper we report on the new method introduced in ATF2 for IP beam parameters characterization which gives a good control over the applied optics and makes the ultra-low beta∗ study possible to conduct. It can be also used for verifying the performance of some of the existing beam instrumentation devices.

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THPMB046

Status and Plans for Completion of the Experimental Programme of the Clic Test Facility Ctf3

acceleration, controls, linac, operation

3347

P.K. Skowroński, R. Corsini, S. Döbert, W. Farabolini, D. Gamba, L. Malina, T. Persson, F. Tecker
CERN, Geneva, Switzerland
W. Farabolini
CEA/DSM/IRFU, France
D. Gamba
JAI, Oxford, United Kingdom

The CLIC Test Facility CTF3 was build, commissioned and operated at CERN by an international collaboration, with the aim of validating the CLIC two beam acceleration scheme, in which the RF power used to accelerate e⁺/e⁻ beams is extracted from a high intensity electron beam. In the past years the main issues of such a scheme were assessed, demonstrating its feasibility. The CTF3 experimental programme is complementing these results by addressing cost and performance subjects, mainly using the CALIFES test beam injector and a full scale two-beam module. In this paper we document the present status and give an outlook to next year run, when the experimental programme should be completed.

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THPMB049

Optics Calibration During Commissioning of the Taiwan Photon Source

optics, lattice, quadrupole, coupling

3357

F.H. Tseng, C.H. Chen, J.Y. Chen, M.-S. Chiu, C.-C. Kuo, Y.-C. Liu, H.-J. Tsai
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source is a 3-GeV low emittance synchrotron light machine with circumference of 518.4m. The lattice is with 24-cell DBA structure and emittance is 1.6 nm-rad. During the commissioning in the past year, we employed MATLAB-based high level applications to calibrate the optical functions in three different operation lattice modes. In particular, we used LOCO (Linear Optics from Closed Orbit) to restore the machine optical functions and reduce emittance coupling ratio. The beam-based alignment (BBA) measurements as well as BPM and corrector errors were identified.

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THPMB056

Witness Beam Production with an RF Gun and a Travelling Wave Booster Linac for AWAKE Experiment at CERN

linac, gun, booster, proton

3378

O. Mete Apsimon, G.X. Xia
UMAN, Manchester, United Kingdom
R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S. Döbert
CERN, Geneva, Switzerland

Funding: This work is supported by the Cockcroft Institute Core Grant and STFC.
AWAKE is a unique experiment that aims to demonstrate the proton driven plasma wakefield acceleration. In this experiment, proton bunches from the SPS accelerator will be injected into a 10m long pre-formed plasma section to form wakefields of hundreds MV/m to several GV/m. A second beam, e.g., the witness beam, will be injected after the protons in an appropriate phase to gain energy from the wakefields. A photo-injector will be utilised to deliver this second beam. It consists of an S-band RF gun followed by a meter long accelerating travelling wave structure (ATS). The RF gun was recuperated from existing PHIN photo-injector. A 3D RF design of the ATS was done by using the CST code and the field maps produced were used to characterise the electron beam dynamics under space charge effect by using the PARMELA code. The impact of the mechanical errors on the beam dynamics were investigated.

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THPMR013

A New Optics for Sirius

dipole, optics, quadrupole, lattice

3413

L. Liu, X.R. Resende, F. H. de Sá
LNLS, Campinas, Brazil

We report on the latest optics modifications for the 3 GeV Sirius electron storage ring presently under construction at the Brazilian Synchrotron Light Laboratory, LNLS. Although the basic parameters are set and frozen, improvements in the magnetic lattice and beam optics are still being implemented. In particular, the central dipole in the 5BA cell has been replaced by an all-permanent-magnet dipole with a thin superbend in the center with peak magnetic field of 3.2 T and the operation mode has now symmetry 5, with 15 low βx straight sections and 5 high βx sections. The 3 GeV ring bare lattice emittance is now 0.25 nm.rad.

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THPMR014

Core-halo Limits and Beam Halo-formation Dynamic

space-charge, focusing, resonance, plasma

3417

M. Valette, P.A.P. Nghiem
CEA/IRFU, Gif-sur-Yvette, France
N. Pichoff
CEA/DSM/IRFU, France

In high intensity linear accelerators, space charge related instabilities and effects are the cause of emittance increase and beam losses. The mechanism of halo formation due to a mismatched beam causing parametric resonances and energy transfer between phase-spaces is one of them. The previously defined one dimensional core-halo limit [1][2] was extended to two dimensional distributions [3][4]. This halo characterization method is applied to a classical case of transport for halo formation studies: the transport of a mismatched beam. Our method provides a core-halo limit that matches the expected halo formation mechanism with a very good precision.
* Appl. Phys. Lett. 104, 074109 (2014)
** Phys. Plasmas, 22, 083115, (2015)
*** IPAC (2015) MOPWA010
**** TBP

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THPMR015

RCDS Optimizations for the ESRF Storage Ring

sextupole, injection, optics, resonance

3420

S.M. Liuzzo, N. Carmignani, L. Farvacque, B. Nash, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

The Robust Conjugate Direction Search (RCDS)* optimizer is applied for online optimizations of the ESRF accelerators. This paper presents the successful application of the algorithm in reducing vertical emittance, improving injection efficiency and increasing lifetime. A new set of sextupole settings to increase chromaticity has been obtained with lifetimes comparable to the existing one. This allows to run with double current in a single bunch, and unifies the optics for few bunch (except 4x10 bunches) and multi-bunch modes.
* X. Huang, J. Corbett, J. Safranek, J. Wu, "An algorithm for online optimization of accelerators", Nucl. Instr. Methods, A 726 (2013) 77-83.

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THPMR035

Low Horizontal Beta Optics for ALBA

lattice, optics, sextupole, dynamic-aperture

3461

G. Benedetti, J. Campmany, Z. Martí
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The ALBA insertion device beamlines have a horizontal and vertical rms source size of 130 and 5.5 microns. Protein crystallography beamlines (Xaloc) would benefit from a reduction of the horizontal and increase of the vertical beam size, to gain spatial resolution and avoid anisotropy effects. A modified lattice with horizontal and vertical beam size of 74 and 9 microns has been setup and tested, breaking the ring symmetry, with different setting of the six neightbouring quadrupoles at each side of the Xaloc insertion device. Such configuration keeps the nominal emittance almost unvaried and the working point is recovered by small changes in the quadrupole strengths of the four symmetric matching sections. A dedicated setting of the nine available sextupole families has been obtained by numerical optimization of the dynamical apertures and tune shifts. The lattice settings have been satisfactorily tested. The measured lifetime is reduced a factor two and the injection efficiency decreases to 60%. Finally, the option of increasing the number of sextupole families, to recover the dynamic aperture and guarantee the injection efficiency, has been studied.

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THPMR050

Studies to Install a Multipole Wiggler by Removing a Chromatic Sextupole in the Diamond Storage Ring

sextupole, injection, optics, lattice

3518

B. Singh, M. Apollonio, R. Bartolini, E. Koukovini-Platia, I.P.S. Martin, T. Pulampong, R.P. Walker
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

Investigations are underway for the possible use of an achromat to install a short multipole wiggler by removing a chromatic sextupole in cell-11 of the storage ring. The effect on emittance and energy spread are found to be small, however the impact on lifetime and injection are very significant if the chromaticity is corrected normally (globally). The MOGA genetic algorithm is used to optimize the lifetime and injection efficiency in this case. We used local mirror chromatic sextupole and other chromatic sextupole family for chromaticity correction in which case the genetic algorithm found solution that restores lifetime and injection efficiency. In this paper the results of MOGA simulations using various schemes for chromaticity correction and test results in presently operational optics will be discussed.

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THPMW032

Measurements on Magnetic Cores for Inductive Adders with Ultra-Flat Output Pulses for CLIC DR Kickers

kicker, flattop, damping, collider

3619

J. Holma, M.J. Barnes, L. Ducimetière
CERN, Geneva, Switzerland

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the DR extraction kickers call for 160 ns duration flattop pulses of ±12.5 kV, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meet the specifications. Two five layer, 3.5 kV, prototype inductive adders have been built at CERN, and used to test passive and active analogue modulation methods to compensate droop and ripple of the output pulses. Recently, magnetic core materials and full-scale magnetic cores have been evaluated for the 12.5 kV prototype inductive adders. These results are presented in this paper and conclusions are drawn concerning the design of the full-scale prototypes.

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THPMW034

Review on the Effects of Characteristic Impedance Mismatching in a Stripline Kicker

impedance, kicker, extraction, damping

3627

C. Belver-Aguilar, M.J. Barnes, L. Ducimetière
CERN, Geneva, Switzerland

A stripline kicker operates as two coupled transmission lines, with two TEM operating modes, known as odd and even modes. The characteristic impedance of these two modes is generally different, both only tend to the same value either when the electrodes are widely separated or when the electrodes are very close to the beam pipe wall. In all other cases, the even mode characteristic impedance is always higher than the odd mode characteristic impedance. The specifications required for a kicker operating in a low emittance ring are usually very challenging. In this situation it is desirable to match the even mode characteristic impedance of the striplines to the resistance of their termination. However a mismatched odd mode impedance can significantly influence the striplines performance. This paper presents predictions for the influence of the odd mode characteristic impedance upon the contribution of each field component, electric and magnetic, to the deflection angle. In addition, the variation of the characteristic impedance and field homogeneity with frequency are presented.

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THPOR001

Tolerance Studies and Dispersion Free Steering for Extreme Low Emittance in the FCC-ee Project

lattice, collider, sextupole, interaction-region

3759

S. Aumon, A. Doblhammer, B. Härer, B.J. Holzer
CERN, Geneva, Switzerland
B. Härer
KIT, Karlsruhe, Germany
K. Oide
KEK, Ibaraki, Japan

The FCC-ee study is investigating the design of a 100 km e⁺/e⁻ circular collider for precision measurements and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. In order to reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2 mm at the IP. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 2 nm for ε_x and 2 pm for ε_y, reducing the coupling ratio to 1/1000. With such requirements, any field errors and sources of coupling will introduce spurious vertical dispersion which degrades emittances, limiting the luminosity of the machine. This paper describes the tolerance study and the impact of errors will affect the vertical emittance. In order to preserve the FCC-ee performances, in particular ε_y, a challenging correction scheme is proposed to keep the coupling and the vertical emittance as low as possible.

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THPOR007

Optics Measurements and Corrections at the Early Commissioning of SuperKEKB

coupling, sextupole, optics, quadrupole

3782

Y. Ohnishi, Y. Funakoshi, H. Koiso, A. Morita, K. Ohmi, K. Oide, H. Sugimoto, D. Zhou
KEK, Ibaraki, Japan
M.E. Biagini, M. Boscolo, S. Guiducci
INFN/LNF, Frascati (Roma), Italy
N. Carmignani, S.M. Liuzzo
ESRF, Grenoble, France

We present experimental results of measurements and corrections of the optics at the early Phase-1 commissioning of SuperKEKB which is a positron-electron collider built to achieve the target luminosity of 8x10³⁵ cm^-2s^-1. We have three stages; the Phase-1 is the commissioning of the machine without the final focus magnets and detector solenoid(no collision); the collision with the final focus system and the Belle II detector will be performed at the Phase-2 and Phase-3. The strategy for the luminosity upgrade is a novel "nano-beam'' scheme found elsewhere*. In order to achieve the target luminosity, the vertical emittance has to be reduced by corrections of machine error measured by orbit responses. The vertical emittance should be achieved to be less than 6 pm(0.2 % coupling) during the Phase-1 by fully utilizing correction tools of skew quadrupole-like coils wound on sextupole magnets and power supplies for each correction coil in quadrupole magnets. In addition to the linear optics, the optics for off-momentum particles is also studied to understand a dynamic aperture affects the Touschek lifetime.
* "SuperB Conceptual Design Report", INFN/AE-07/2, SLAV-R-856, LAL 07-15, (2007).

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THPOR010

CEPC Parameter Choice and Partial Double Ring Design

luminosity, sextupole, dynamic-aperture, optics

3788

D. Wang, S. Bai, T.J. Bian, X. Cui, Z. Duan, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, Y. Wang, M. Xiao, J.Y. Zhai, C. Zhang, Y. Zhang
IHEP, Beijing, People's Republic of China
W. Chou
Fermilab, Batavia, Illinois, USA
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218)
In order to avoid the pretzel orbit, CEPC is proposed to use partial double ring scheme in CDR. Based on crab waist scheme, we hope to either increase the luminosity with same beam power as Pre-CDR, or reduce the beam power while keeping the same luminosity in Pre-CDR. FFS with crab sextupoles has been developed and the arc lattice was redesigned to acheive the lower emittance for crab waist scheme.

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THPOR011

Design study of CEPC Alternating Magnetic Field Booster

dipole, sextupole, dynamic-aperture, booster

3791

T.J. Bian, S. Bai, X. Cui, J. Gao, D. Wang, Y. Wang, M. Xiao, C. Zhang
IHEP, Beijing, People's Republic of China
Y. Cai
SLAC, Menlo Park, California, USA
M. Koratzinos
DPNC, Genève, Switzerland
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

CEPC is next generation circular collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120GeV but the injected beam only 6GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. We propose to operate the booster ring as a large wiggler at low beam energies and as a normal ring at high energies to avoid the problem of very low dipole magnet fields.

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THPOR023

The FCC-ee Interaction Region Magnet Design

solenoid, quadrupole, detector, interaction-region

3824

M. Koratzinos, A.P. Blondel
DPNC, Genève, Switzerland
M. Benedikt, B.J. Holzer, F. Zimmermann, J. van Nugteren
CERN, Geneva, Switzerland
A.V. Bogomyagkov, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia
K. Oide
KEK, Ibaraki, Japan

The design of the region close to the interaction point of the FCC-ee experiments is especially challenging. The beams collide at an angle (±15 mrad) in the high-field region of the detector solenoid. Moreover, the very low vertical β* of the machine necessitates that the final focusing quadrupoles have a distance from the IP (L*) of around 2 m and therefore are inside the main detector solenoid. The beams should be screened from the effect of the detector magnetic field, and the emittance blow-up due to vertical dispersion in the interaction region should be minimized, while leaving enough space for detector components. Crosstalk between the two final focus quadrupoles, only about 6 cm apart at the tip, should also be minimized.

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THPOR025

Wedge Absorbers for Final Cooling for a High-Energy High-Luminosity Lepton Collider

experiment, optics, betatron, collider

3832

D.V. Neuffer
Fermilab, Batavia, Illinois, USA
T.A. Mohayai
IIT, Chicago, Illinois, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA
D.J. Summers
UMiss, University, Mississippi, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
A high-energy high-luminosity muon collider scenario requires a "final cooling" system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittance by a factor of ~5. Implementation will require optical matching of the exiting beam into downstream acceleration systems.

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THPOR029

First Start-to-End BBA Results in the CLIC RTML

sextupole, quadrupole, coupling, alignment

3841

Y. Han, L. Ma
SDU, Shandong, People's Republic of China
A. Latina, D. Schulte
CERN, Geneva, Switzerland

CLIC is a design study for a 3 TeV linear collider designed for the high-energy frontier in the post-LHC era. The Ring To Main Linac (RTML) part of CLIC is a long section that must transport the electron and the positron bunches through more than 20 km of beamlines, with minimal emittance growth. A sequence of three beam-based alignment (BBA) techniques must be used to transport the beam: one-to-one correction (OTO), dispersion-free steering (DFS), and sextupole correction (SCS). The performance of the whole correction procedure is tested under several realistic imperfections: magnets position offsets, magnets rotation errors, magnets strength errors and emittance measurement errors. The results show that the emittance growth budgets can be met both in the horizontal and vertical planes.

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THPOR032

Effect and Optimisation of Non-Linear Chromatic Aberrations of the CLIC Drive Beam Recombination at CTF3

optics, simulation, sextupole, operation

3852

D. Gamba, R. Corsini, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The CLIC design relies on the two-beam acceleration principle, i.e. the energy transfer from the so called drive beam to the main colliding beams. At the CLIC Test Facility (CTF3) at CERN the feasibility of this principle is being tested in terms of performance and achievable specifications. The high-current drive beam is generated by recombining its parts in a delay loop and a combiner ring. Preserving the drive beam emittance during the recombination process is crucial to ensure beam-current and power production stability. Present theoretical and experimental studies show that non-linear energy dependence of the transverse optics heavily spoils the quality of the recombined beam. Conventionally these effects are cured by means of non-linear corrections using sextupoles. In this work we propose a mitigation of these effects by optimising the linear lattice, leading to a more robust and easy to operate drive beam recombination complex. The latest results are presented.

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THPOR040

Emittance Growth by Misalignments and Jitters in SuperKEKB Injector Linac

linac, acceleration, quadrupole, simulation

3871

Y. Seimiya, Y. Enomoto, K. Furukawa, T. Higo, T. Kamitani, F. Miyahara, Y. Ohnishi, M. Satoh, T. Suwada, M. Tanaka
KEK, Ibaraki, Japan

Funding: This work was partly supported by JSPS KAKENHI Grant Number 16K17545.
SuperKEKB injector linac have to transport high-charged beam with low emittance to SuperKEKB ring for high luminosity, 8¥times10³⁵. For the low emittance, photocathode RF gun was adopted as electron source. One of the main reason of the beam emittance blow-up electron linac is generally induced by wakefield in acceleration cavities. A charged beam with a offset from a center of a cavity is affected by the wakefield depending on the offset size in the acceleration cavity and the beam emittance is increased. This emittance blow-up can be eliminated by appropriate steering magnet control so as to cancel the wake effect in the acceleration cavity. We perform particle tracking simulation with some misalignments and beam jitter. Emittance growth by the misalignments and the beam jitter is evaluated in this report.

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THPOR045

Analytical Estimation of ATF Beam Halo Distribution

scattering, vacuum, electron, damping

3888

D. Wang, J. Gao
IHEP, Beijing, People's Republic of China
P. Bambade
LAL, Orsay, France
T. Naito
KEK, Ibaraki, Japan

Funding: Work supported by the National Foundation of Natural Sciences (11505198 and 11575218)
Halo distribution is a key topic for background study. This paper has developed an analytical method to give an estimation of ATF beam halo distribution. The equilibrium particle distribution of the beam tail in the ATF damping ring is calculated analytically with different emittance and different vacuum degree. The analytical results agree the measurements very well. This is a general method which can be applied to any electron rings.

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THPOR047

Preliminary Concept and Key Technologies of HIEPA Accelerator

collider, synchrotron, luminosity, brightness

3895

Z.R. Zhou, Q. Luo, L. Wang, W. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11375178 and 11575181) and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046
High energy physicists proposed a new collider: super tau-charm factory. The name of the project is high intensity electron positron accelerator facility. As high intensity electron positron collider, it runs in an energy range of 2-7 GeV. As an advanced light source, it can also provide high quality synchrotron radiation from VUV to soft X-ray. The facility will be a symmetrical two-ring collider located at Hefei. This paper shows preliminary conception of the storage rings.

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THPOW001

Design of a 4.6-Cell RF Gun for the PHIL accelerator at LAL

gun, cavity, impedance, coupling

3922

P. Chen, C. Bruni, S. Chancé, L. Garolfi, A. Gonnin, P. Lepercq, T. Vinatier
LAL, Orsay, France

A photo-injector with 4.6-cell and resonate frequency of 2.998 GHz has been designed and studied to replace the 2.5-cell RF gun + booster association. The cavity iris shape and dimensions were simulated systematically to optimize the shunt impedance. In this study, electron beam reaches to 9.7 MeV with a moderate peak accelerat-ing gradient of 80 MV/m. Considering a beam charge of 1 nC/bunch, average transverse emittance of ~ 5.9 πmm mrad and energy spread of ~ 0.8% can be obtained at the exit of the gun. The RF input power is only 10.2 MW due to the high shunt impedance. Asymmetry of the electric field due to the coupling port has also been studied using 3D codes for RF and beam dynamics calculations. We will present the RF design and beam calculations results.

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THPOW003

Highlights on Metallic Photocathodes Used in SRF Gun

gun, cathode, SRF, laser

3928

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

For the accelerator-based light sources and the electron colliders, the development of photoinjectors has become a key technology. Especially for the superconducting radio frequency cavity based injector (SRF Gun), the searching for better photocathodes is always a principal technical challenge. To use metallic photocathodes for ELBE SRF Gun is the primary choice to prevent cavity contamination. In this contribution, we will report the investigation of Magnesium (Mg) in ELBE SRF gun, including laser cleaning treatment and the measurement on quantum efficiency, Schottky effect, dark current and damage threshold.
The work is supported by the European Community under the FP7 programme (EuCARD-2 and LA3NET) and by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.

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THPOW010

Study on Characteristics of Asymmetric Centre Iris of Photocathode Microwave Electron Gun

gun, electron, electromagnetic-fields, cathode

3951

Zh. X. Tang, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China

The characteristics of asymmetric iris between first cell and second cell of 1.6 cell photocathode gun are studied. For π-mode, the RF radial field of two sides of the iris is non anti-symmetric. Thus, the RF transverse force at the iris is not negligible. In this paper, we present the status of the optimization simulations, using the SUPERFISH and PARMELA particle-in-cell code. Numerical results of beam dynamics show that it can improve the emittance at the exit of the gun.

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THPOW020

S-Band Photoinjector Investigations by Multiobjective Genetic Optimizer

laser, brightness, gun, cathode

3979

H.J. Qian, D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA

Photoinjectors has witnessed great progress in the past few decades, with low duty cycle high gradient guns, such as normal conducting S/L band gun, pushing the peak beam brightness frontier, and CW guns, such as DC gun, SRF gun and VHF gun, pushing the average beam brightness frontier. Due to different degrees of complexity, pulsed high gradient photoinjectors are usually optimized by manual scans, while CW photoinjectors are optimized by multi-objective genetic optimizers. In this paper, a multi-objective genetic optimizer is used to revisit S-band photoinjector beam brightness optimizations, showing a trade-off between peak current and transverse emittance, with the optimized injector layout depending on bunch charge and peak current. For 200 pC case, the final beam core brightness at injector exit is close to cathode maximum brightness in the 'cigar beam' regime. Assuming a thermal emittance of 0.5 μm/mm and a beam charge of 200 pC, about 90 nm slice emittance at 20 A peak current is achieved.

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THPOW021

Generation of Homogeneous and Patterned Electron Beams using a Microlens Array Laser-Shaping Technique

laser, electron, solenoid, experiment

3983

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Edstrom, P. Piot, J. Ruan, J.K. Santucci
Fermilab, Batavia, Illinois, USA
W. Gai, G. Ha, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
G. Qiang
TUB, Beijing, People's Republic of China

Funding: Northern Illinois University - US DOE contract No. DE-SC0011831. Fermilab - US DOE contract No. DE-AC02-07CH11359. The Argonne wakefield facility - US DOE contract No. DE-AC02-06CH11357.
In photocathodes the achievable electron-beam parameters are controlled by the laser used to trigger the photoemission process. Non-ideal laser distribution hampers the final beam quality. Laser inhomogeneities, for instance, can be "amplified" by space-charge force and result in fragmented electron beams. To overcome this limitation laser shaping methods are routinely employed. In the present paper we demonstrate the use of simple microlens arrays to dramatically improve the transverse uniformity. We also show that this arrangement can be used to produce transversely-patterned electron beams. Our experiments are carried out at the Argonne Wakefield Accelerator facility.

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THPOW023

Intrinsic Emittance Reduction in Transmission Mode Photocathodes

electron, scattering, laser, cathode

3987

H. Lee, I.V. Bazarov, L. Cultrera
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describe the photoemission process, however, some photocathode characteristics such as their thickness have not been completely exploited to further improve the brightness of the generated electron beam. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction on the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering events experienced by electrons during their transit towards the cathode surface. This scattering will expect the further emittance reduction than the no scattering at the cryo-temperatures.

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THPOW025

Photocathode Growth and Characterization Advances at Cornell University

electron, photon, cathode, gun

3990

L. Cultrera, A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, H. Lee, R.A. Lipton, T.P. Moore
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Alkali-antimonides based photocathodes have demonstrated outstanding performance in high brightness electron beam production suitable for a wide range of applications such as FELs, ERLs and UED and for use in photomultiplier devices with picosecond resolution aimed at photon counting application in medicine and High Energy Physics. The photocathode laboratory at Cornell University is dedicated to studying the growth procedures and characterizing the properties in a wide range of photocathodes materials. Different experimental arrangements and alkali metal sources have been successfully explored to date to synthesize photosensitive materials. Recent work on commissioning a new growth chamber equipped with effusion cells loaded with pure metal allowing uniform deposition over large area substrates resulted on successful growth of photocathodes with extended sensitivity in the IR part of the spectrum and high efficiency alkali antimonides containing Rb metal. This and other advances aimed at demonstrating superior photocathodes will be presented.

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THPOW026

LLNL X-band RF Gun Results

laser, electron, gun, dipole

3993

R.A. Marsh, G.G. Anderson, C.P.J. Barty, D.J. Gibson
LLNL, Livermore, California, USA
Y. Hwang
UCI, Irvine, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station and Inverse Compton Scattering (ICS) x-ray source has been built and commissioned at LLNL. The electron beam source is a unique 5.59 cell RF photoinjector, which will be described in detail, including: quantum efficiency, emittance measurements, energy spread and jitter, final focus spot size and stability, laser profile and final transport, and consistency with expectations based on beam dynamics simulations.

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THPOY027

Commissioning Status of SuperKEKB Injector Linac

electron, gun, linac, injection

4152

M. Satoh, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Iwase, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, S. Kazama, M. Kikuchi, H. Koiso, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, Y. Seimiya, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

The SuperKEKB main ring is currently being constructed for aiming at the peak luminosity of 8 x 10³⁵ cm^-2s⁻¹. The electron/positron injector linac upgrade is also going on for increasing the intensity of bunch charge with keeping the small emittance. The key upgrade issues are the construction of positron damping ring, a new positron capture system, and a low emittance photo-cathode rf electron source. The injector linac beam commissioning started in the October of 2013. In this paper, we report the present status and future plan of SuperKEKB injector commissioning.

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FRXBA01

Beam Halo Characterization and Mitigation

linac, operation, collimation, simulation

4248

A.V. Aleksandrov
ORNL, Oak Ridge, Tennessee, USA

Beam halo is a serious issue in many machines, such as high intensity linacs and synchrotrons. This presentation reviews recent advances in halo characterization techniques, as well as methods to mitigate beam halo, such as collimation with associated handling of created secondary particles.

Slides FRXBA01 [17.743 MB]

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FRXBB01

Achieved Performance of an All X-band Photo-injector

gun, cathode, laser, electron

4253

C. Limborg, C. Adolphsen, M.P. Dunning, R.K. Jobe, H. Li, D.J. McCormick, T.O. Raubenheimer, T. Vecchione, A.R. Vrielink, F.Y. Wang, S.P. Weathersby
SLAC, Menlo Park, California, USA

Funding: Work funded by DOE/SU Contract DE-AC02-76-SF00515
Building more compact accelerators to deliver high brightness electron beams for the generation of high flux, highly coherent radiation is a priority for the photon science community. A relatively straightforward reduction in footprint can be achieved by using high-gradient X-Band (11.4 GHz) RF technology. This talk presents the all X-band photo-injector facility at SLAC, covering the benefits of using this technology and highlighting the performance achieved.

Slides FRXBB01 [40.418 MB]

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