IPAC2019 - List of Keywords (brightness)

Paper	Title	Other Keywords	Page
MOPTS100	Transverse Emittance Measurement in the CERN Proton Synchrotron in View of Beam Production for the High-Luminosity LHC	emittance, proton, optics, betatron	1106
	E. Senes, J. Emery, V. Forte, M.A. Fraser, A. Guerrero, A. Huschauer, F. Roncarolo, J.L. Sirvent, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade project the improvements required to achieve the parameters of the future beams for the High-Luminosity LHC are being studied and implemented. In order to deliver high brightness beams, control over the beam intensity and emittance is fundamental. Therefore, a highly accurate and reliable transverse emittance measurement is essential. Presently at the CERN Proton Synchrotron, the only operationally available emittance monitors not impacting the facility beam production are the flying wire scanners used to measure the circulating beam profile. The wire scanners will be replaced with a new generation in the next two years and a prototype is already installed. The prototype has been commissioned with beams featuring a wide range of intensities and emittances. This paper evaluates the performance of the prototype with respect to the present system via beam-based measurements. The transverse emittance measurement is discussed, considering the different potential error contributions to the measurement, such as knowledge of the machine optics and the dispersive contribution to the beam size.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS100
About •	paper received ※ 02 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS101	Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation	emittance, simulation, proton, scattering	1110
	A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis CERN, Geneva, Switzerland E. Senes Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUZPLS2	Beam Dynamics Study in the HEPS Storage Ring	lattice, storage-ring, emittance, photon	1203
	Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao IHEP, Beijing, People’s Republic of China
	The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.
	Slides TUZPLS2 [9.517 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW011	Status of the PETRA IV project	emittance, lattice, timing, synchrotron	1404
	I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang DESY, Hamburg, Germany
	Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB032	The CompactLight Design Study Project	FEL, linac, electron, undulator	1756
	G. D’Auria, S. Di Mitri, R.A. Rochow Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy M. Aicheler HIP, University of Helsinki, Finland A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi, Turkey D. Alesini, M. Bellaveglia, B. Buonomo, F. Cardelli, M. Croia, M. Diomede, M. Ferrario, A. Gallo, A. Giribono, L. Piersanti, B. Spataro, C. Vaccarezza INFN/LNF, Frascati, Italy R. Apsimon, A. Castilla Cockcroft Institute, Lancaster University, Lancaster, United Kingdom J.M. Arnesano, F. Bosco, L. Ficcadenti, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy A. Bernhard, J. Gethmann KIT, Karlsruhe, Germany G. Burt Lancaster University, Lancaster, United Kingdom M. Calvi, T. Schmidt, K. Zhang PSI, Villigen PSI, Switzerland H.M. Castaneda Cortes, J.A. Clarke, D.J. Dunning, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.W. Cross, L. Zhang USTRAT/SUPA, Glasgow, United Kingdom G. Dattoli, F. Nguyen, A. Petralia ENEA C.R. Frascati, Frascati (Roma), Italy R.T. Dowd, D. Zhu AS - ANSTO, Clayton, Australia W.D. Fang SINAP, Shanghai, People’s Republic of China A. Faus-Golfe, Y. Han LAL, Orsay, France E.N. Gazis, N. Gazis National Technical University of Athens, Athens, Greece R. Geometrante, M. Kokole KYMA, Trieste, Italy V.A. Goryashko, M. Jacewicz, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden X.J.A. Janssen, J.M.A. Priem VDL ETG, Eindhoven, The Netherlands A. Latina, X. Liu, C. Rossi, D. Schulte, S. Stapnes, X.W. Wu, W. Wuensch CERN, Geneva, Switzerland O.J. Luiten, P.H.A. Mutsaers, X.F.D. Stragier TUE, Eindhoven, The Netherlands J. Marcos, E. Marín, R. Muñoz Horta, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain G. Taylor The University of Melbourne, Melbourne, Victoria, Australia
	Funding: This project has received funding from the European Union’s Horizon2020 research and innovation programme under grant agreement No 777431 The H₂020 CompactLight Project (www. CompactLight.eu) aims at designing the next generation of compact X-rays Free-Electron Lasers, relying on very high gradient accelerating structures (X-band, 12 GHz), the most advanced concepts for bright electron photo injectors, and innovative compact short-period undulators. Compared to existing facilities, the proposed facility will benefit from a lower electron beam energy, due to the enhanced undulators performance, and will be significantly more compact, with a smaller footprint, as a consequence of the lower energy and the high-gradient X-band structures. In addition, the whole infrastructure will also have a lower electrical power demand as well as lower construction and running costs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB032
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB097	Recent Progress on the Design of Normal Conducting APEX-II VHF CW Electron Gun	cavity, gun, electron, cathode	1891
	D. Li, H.Q. Feng, D. Filippetto, M.J. Johnson, A.R. Lambert, T.H. Luo, C.E. Mitchell, J. Qiang, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells LBNL, Berkeley, California, USA H.Q. Feng TUB, Beijing, People’s Republic of China
	Funding: Director of Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 We report recent progress on the design of a normal conducting CW electron gun, APEX-II (Advanced Photo-injector EXperiment-II) at Lawrence Berkeley National Laboratory. APEX-II is an upgrade of the successful APEX gun and the LCLS-II (Linac Coherent Light Source-II) injector, aiming at applications for Free electron laser (FEL) such as LCLS-II High Energy upgrade, UED (Ultrafast Electron Diffraction) and UEM (Ultrafast Electron Microscopy). The APEX-II adopted a two-cell cavity design with resonant frequency of 162.5 MHz. The APEX-II gun is targeting to achieve exceeding 30 MV/m of launch gradient at the cathode and output energy above 1.5 MeV with transverse emittance of 0.1 um at 100 pC. Advanced MOGA optimization technique has been used for both the RF cavity design and extensive beam dynamics studies using APEX-like and LCLS-II like injector layout. Detailed RF designs, beam dynamics studies, preliminary engineering design and FEA analysis will be presented, with cavity features that were demonstrated to be crucial in the operation of the APEX gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB097
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPTS024	Design of a Full C-Band Injector for Ultra-High Brightness Electron Beam	gun, emittance, cathode, klystron	1979
	D. Alesini, F. Cardelli, G. Castorina, M. Croia, M. Diomede, M. Ferrario, A. Gallo, A. Giribono, B. Spataro, C. Vaccarezza, A. Vannozzi INFN/LNF, Frascati (Roma), Italy
	High gradient rf photo-injectors have been a key development to enable several applications of high quality electron beams. They allow the generation of beams with very high peak current and low transverse emittance, satisfying the tight demands for free-electron lasers, energy recovery linacs, Compton/Thomson sources and high-energy linear colliders. In the paper we present the design of a new full C-band RF photo-injector recently developed in the framework of the XLS-Compact Light design study and of the EuPRAXIA@SPARC_LAB proposal. It allows to reach extremely good beam performances in terms of beam emittance (at the level of few hundreds nm), energy spread and peak current. The photo-injector is based on a very high gradient (>200 MV/m) ultra-fast (RF pulses <200 ns) C-band RF gun, followed by two C band TW structures. Different types of couplers for the 1.6 cell RF gun have been considered and also a new compact low pulsed heating coupler working on the TM020 mode on the full cell has been proposed. In the paper we report the design criteria of the gun, the powering system, and the results of the beam dynamics simulations. We also discuss the case of 1 kHz repetition rate.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS024
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPTS047	Improvement of 6D Brightness by a 1.4-cell Photocathode RF Gun for MeV Ultrafast Electron Diffraction	gun, emittance, electron, cathode	2033
	Y. Song Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China K. Fan, C.-Y. Tsai, Y.T. Yang HUST, Wuhan, People’s Republic of China J. Yang ISIR, Osaka, Japan
	Recent research indicates that ultrafast electron diffraction and microscopy (UED/M) have unprecedented potential in probing ultrafast dynamic processes, especially in organic and biological materials. However, reaching the required brightness while maintaining high spatiotemporal resolution requires new design of electron source. In order to produce ultrashort electron beam with extreme high brightness, a 1.4-cell RF gun is being developed to reach higher acceleration gradient near the photocathode and thus suppress the space charge effect in the low energy region. Simulation of the 1.4-cell RF photocathode gun shows considerable improvement in bunch length, emittance and energy spread, which all lead to better temporal and spatial resolution comparing to traditional 1.6-cell RF photocathode gun. The results demonstrate the feasibility of sub-ps temporal resolution with normalized emittance less than 0.1 πmm·mrad while maintaining 1 pC electron pulse.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS047
About •	paper received ※ 24 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPTS076	RF Design of APEX2 Cavities	gun, cavity, cathode, electron	2094
	T.H. Luo, H.Q. Feng, D. Filippetto, M.J. Johnson, A.R. Lambert, D. Li, C.E. Mitchell, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells LBNL, Berkeley, California, USA H.Q. Feng TUB, Beijing, People’s Republic of China
	Funding: Director of Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 APEX2 is a proposed high repetition rate, high brightness electron source based on CW normal conducting RF cavities, aiming to further extend the brightness performance for FEL and UED/UEM beyond APEX. APEX2 consists of two cavities, one gun cavity for generating photo-electrons and one following cavity for beam energy boosting. In this paper, we present the RF design of the APEX2 cavities. The design has considered both beam dynamics requirements and engineering feasibility. A novel geometry optimization method with Genetic Algorithm has been implemented in the design procedure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS076
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPTS111	Study on Improving Durability of Cs-Te Photocathode for an RF-gun	cathode, gun, electron, vacuum	2182
	T. Tamba, J. Miyamatsu, K. Sakaue, M. Washio Waseda University, Tokyo, Japan
	At Waseda University, we have been studying for high quality electron beam generation using 1.6 cell Cs-Te photocathode rf-gun. We use photocathode as the electron source, which can generate high- quality electron beam such as low emittance, and short bunch. The performance of photocathode is evaluated mainly in terms of quantum efficiency (Q.E.) and lifetime. Cs-Te photocathode used in the rf-gun is known for high Q.E. about 10% with UV light and relatively longer lifetime among semiconductor photocathodes. Since it is a hard environment for photocathode inside the gun, it is necessary to replace the photocathode every several months. In other words, in order to achieve long-term operation of rf-gun, it is necessary to find highly durable photocathode recipe. It has been reported that the Cs-Te photocathode by co-evaporation can produce a photocathode having a longer lifetime as compared with the sequential evaporation. Moreover, we have done studies to improve lifetime and durability of Cs-Te photocathode by coating the cathode surface with CsBr thin film. In this conference, we report the evaluation results of Cs-Te photocathode by co-evaporation, CsBr coating and future prospects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS111
About •	paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP022	Design and Construction of the CERN SPS Extraction Protection Elements for LIU	extraction, vacuum, simulation, quadrupole	2359
	B. Balhan, C. Baud, J.C.C.M. Borburgh, M.A. Fraser, M. Hourican, L.O. Jorat, F.-X. Nuiry, S. Pianese CERN, Geneva, Switzerland
	At CERN, the SPS synchrotron is equipped with two fast extraction channels towards the LHC. As a part of the LHC injector upgrade project (LIU), the protection devices upstream of the septa in both extraction channels will be upgraded. Various failure scenarios have been studied and presented in the past, but the definitive approach for the equipment protection upgrade for each channel has now been determined. This paper describes the consequences of the most significant failure scenarios and the impact of the heat deposition in the diluter. The resulting material stresses are evaluated. The detailed layout for the extraction protection equipment for each extraction channel is outlined. The final layout consists of a extended diluter in Long Straight Section (LSS) 6 (TPSG6) and the installation of an additional movable absorber (TPSC4) upstream of the quadrupole in front of the existing protection equipment in LSS 4. The detailed mechanical design of the TPSC4 and the construction status of both TPSC4 and TPSG6 are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP022
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPGW022	A Numerical Analysis to Choose the Most Performing Optical Transition Radiation Screen	target, electron, radiation, site	2518
	F. Cioeta, D. Alesini, A. Variola INFN/LNF, Frascati (Roma), Italy M. Ciambrella, A. Mostacci Sapienza University of Rome, Rome, Italy D. Cortis, M. Marongiu, V. Pettinacci INFN-Roma, Roma, Italy
	Optical Transition Radiation (OTR) screen represents the most appropriate instrument to measure and verify the characteristics of a beam spot size produced by a particle accelerator. In order to measure such beam properties, OTR screens have to sustain thermal and mechanical stresses due to the energy that several bunches deposit. Owing to these requirements, it is essential to identify the more suitable material to optimize the OTR dimensions and to get reliable measures from the diagnostic system. In this paper, we describe a numerical procedure to choose the most performing material taking into account the physical requirements of a multi-bunch high brightness. The procedure is based on a dedicated ANSYS script able to evaluate the fatigue life time of the material considering a high number of thermal cycles generated by several bunches. The main characteristic of this script is the capability to simulate the real thermal and mechanical effect on the target that the hitting particle beam produces. The numerical procedure has been applied to compare the performance of three relevant materials-Aluminium, Silicon and Graphite simulating a beam hitting with well-known parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW022
About •	paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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WEPRB024	Low Power RF Test of a Quadrupole-free X-Band Mode Launcher for High Brightness Applications	GUI, quadrupole, simulation, electron	2856
	G. Torrisi, L. Celona, S. Gammino, O. Leonardi, G. Sorbello INFN/LNS, Catania, Italy G. Castorina Sapienza University of Rome, Rome, Italy V.A. Dolgashev SLAC, Menlo Park, California, USA L. Faillace INFN-Milano, Milano, Italy G.S. Mauro INFN/LNL, Legnaro (PD), Italy G. Sorbello University of Catania, Catania, Italy B. Spataro INFN/LNF, Frascati, Italy
	In this work we present the low power RF characterization of a novel TM01 X-band mode launcher for the new generation of high brightness RF photo-injectors. The proposed mode launcher exploits a fourfold symmetry which minimizes both the dipole and the quadrupole fields in order to mitigate the emittance growth in the early stages of the acceleration process. Two identical aluminum mode launchers have been assembled and measured in back-to-back configurations for three different central waveguide lengths. From the back-to-back results we infer the performance of each mode launcher. The low power RF test, performed at the Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud (INFN-LNS), validate both the numerical simulations and the quality of fabrication. An oxygen-free high-conductivity copper version of the device is being manufactured for high power and ultra high vacuum tests that are planned to be conducted at SLAC
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB024
About •	paper received ※ 09 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPRB072	Ultra-High Gradient Short RF Pulse Gun	gun, electron, cathode, emittance	2987
	S.P. Antipov, P.V. Avrakhov, S.V. Kuzikov, A. Liu Euclid TechLabs, LLC, Solon, Ohio, USA G. Ha, J.G. Power ANL, Argonne, Illinois, USA
	Funding: DOE SBIR DE-SC0018709 High brightness beams enable novel applications like x-ray free electron lasers and ultrafast electron microscopes. High brightness beams essentially consist of a large number of electrons in a small phase space volume, i.e. a high peak current. When such beams are generated from the cathode, there is a strong space charge force, which elongates the bunch and reduces its brightness. An optimal solution is to raise the accelerating voltage in the gun. However, the maximum gradient is limited by the effects of RF breakdown. The probability of RF breakdown is reduced as the RF pulse length decreases. We present a development of an electron photoinjector operating with short RF pulse, 10 ns scale. We have designed an X-band gun including the RF design, beam quality optimization, and engineering. The gun will be fed by 10 ns, 300 MW RF pulse generated at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. We also manufactured an aluminum prototype and measured its microwave properties, most importantly, fill time. The proposed high brightness beam source can be used as the main beam in wakefield accelerators. It will find commercial applications in ultrafast electron diffraction and microscopy systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB072
About •	paper received ※ 21 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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WEPTS047	Space Charge Driven Resonances in the CERN PS	resonance, space-charge, simulation, lattice	3216
	F. Asvesta NTUA, Athens, Greece H. Bartosik, A. Huschauer, Y. Papaphilippou CERN, Geneva, Switzerland
	In the CERN Proton Synchrotron space charge driven resonances are excited around the operational working point due to the periodicity of the optics functions. In this paper, the resonances are studied using analytical methods, i.e. the evaluation of the resonance driving terms connected to the space charge potential of Gaussian distributions. Furthermore, the resonances are characterized in measurements and simulations for various beams. The beams considered are different in terms of brightness, in order to study the dependence of the resonance strength on the space charge force.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS047
About •	paper received ※ 17 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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Paper

Title

Other Keywords

Page

MOPTS100

Transverse Emittance Measurement in the CERN Proton Synchrotron in View of Beam Production for the High-Luminosity LHC

emittance, proton, optics, betatron

1106

E. Senes, J. Emery, V. Forte, M.A. Fraser, A. Guerrero, A. Huschauer, F. Roncarolo, J.L. Sirvent, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade project the improvements required to achieve the parameters of the future beams for the High-Luminosity LHC are being studied and implemented. In order to deliver high brightness beams, control over the beam intensity and emittance is fundamental. Therefore, a highly accurate and reliable transverse emittance measurement is essential. Presently at the CERN Proton Synchrotron, the only operationally available emittance monitors not impacting the facility beam production are the flying wire scanners used to measure the circulating beam profile. The wire scanners will be replaced with a new generation in the next two years and a prototype is already installed. The prototype has been commissioned with beams featuring a wide range of intensities and emittances. This paper evaluates the performance of the prototype with respect to the present system via beam-based measurements. The transverse emittance measurement is discussed, considering the different potential error contributions to the measurement, such as knowledge of the machine optics and the dispersive contribution to the beam size.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS100

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paper received ※ 02 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS101

Study of the Transverse Emittance Blow-Up Along the Proton Synchrotron Booster Cycle During Wire Scanner Operation

emittance, simulation, proton, scattering

1110

A. Santamaría García, F. Antoniou, H. Bartosik, J.A. Briz Monago, G.P. Di Giovanni, A. Guerrero, J.R. Hunt, B. Mikulec, F. Roncarolo, E. Senes, V. Vlachoudis
CERN, Geneva, Switzerland
E. Senes
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS101

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUZPLS2

Beam Dynamics Study in the HEPS Storage Ring

lattice, storage-ring, emittance, photon

1203

Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People’s Republic of China

The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.

Slides TUZPLS2 [9.517 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW011

Status of the PETRA IV project

emittance, lattice, timing, synchrotron

1404

I.V. Agapov, R. Bacher, M. Bieler, R. Bospflug, R. Brinkmann, Y.-C. Chae, H.C. Chao, H.T. Duhme, M. Ebert, H.-J. Eckoldt, H. Ehrlichmann, X.N. Gavaldà, M. Hüning, U. Hurdelbrink, J. Keil, J. Klute, M. Körfer, B. Krause, G. Kube, W. Leemans, L. Lilje, F. Obier, A. Petrov, N. Plambeck, J. Prenting, G.K. Sahoo, H. Schlarb, M. Schlösser, F. Schmidt-Föhre, M. Schmitz, C.G. Schroer, T. Tempel, M. Thede, M. Tischer, R. Wanzenberg, E.F. Weckert, T. Wilksen, K. Wittenburg, J.X. Zhang
DESY, Hamburg, Germany

Since 2016 DESY has been pursuing R&D towards upgrading its PETRA synchrotron light source to a fourth-generation machine, PETRA IV, which is expected to start operation in 2027. The conceptual design of a 6 GeV seven-bend-achromat-based lattice with an approx. 10pm emittance along with critically important technical systems has been completed. We will present the status of the project, the expected parameter space of the facility, and lattice design and beam dynamics issues for the main ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW011

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB032

The CompactLight Design Study Project

FEL, linac, electron, undulator

1756

G. D’Auria, S. Di Mitri, R.A. Rochow
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Aicheler
HIP, University of Helsinki, Finland
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi, Turkey
D. Alesini, M. Bellaveglia, B. Buonomo, F. Cardelli, M. Croia, M. Diomede, M. Ferrario, A. Gallo, A. Giribono, L. Piersanti, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati, Italy
R. Apsimon, A. Castilla
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
J.M. Arnesano, F. Bosco, L. Ficcadenti, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
A. Bernhard, J. Gethmann
KIT, Karlsruhe, Germany
G. Burt
Lancaster University, Lancaster, United Kingdom
M. Calvi, T. Schmidt, K. Zhang
PSI, Villigen PSI, Switzerland
H.M. Castaneda Cortes, J.A. Clarke, D.J. Dunning, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.W. Cross, L. Zhang
USTRAT/SUPA, Glasgow, United Kingdom
G. Dattoli, F. Nguyen, A. Petralia
ENEA C.R. Frascati, Frascati (Roma), Italy
R.T. Dowd, D. Zhu
AS - ANSTO, Clayton, Australia
W.D. Fang
SINAP, Shanghai, People’s Republic of China
A. Faus-Golfe, Y. Han
LAL, Orsay, France
E.N. Gazis, N. Gazis
National Technical University of Athens, Athens, Greece
R. Geometrante, M. Kokole
KYMA, Trieste, Italy
V.A. Goryashko, M. Jacewicz, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
X.J.A. Janssen, J.M.A. Priem
VDL ETG, Eindhoven, The Netherlands
A. Latina, X. Liu, C. Rossi, D. Schulte, S. Stapnes, X.W. Wu, W. Wuensch
CERN, Geneva, Switzerland
O.J. Luiten, P.H.A. Mutsaers, X.F.D. Stragier
TUE, Eindhoven, The Netherlands
J. Marcos, E. Marín, R. Muñoz Horta, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
G. Taylor
The University of Melbourne, Melbourne, Victoria, Australia

Funding: This project has received funding from the European Union’s Horizon2020 research and innovation programme under grant agreement No 777431
The H₂020 CompactLight Project (www. CompactLight.eu) aims at designing the next generation of compact X-rays Free-Electron Lasers, relying on very high gradient accelerating structures (X-band, 12 GHz), the most advanced concepts for bright electron photo injectors, and innovative compact short-period undulators. Compared to existing facilities, the proposed facility will benefit from a lower electron beam energy, due to the enhanced undulators performance, and will be significantly more compact, with a smaller footprint, as a consequence of the lower energy and the high-gradient X-band structures. In addition, the whole infrastructure will also have a lower electrical power demand as well as lower construction and running costs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB032

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB097

Recent Progress on the Design of Normal Conducting APEX-II VHF CW Electron Gun

cavity, gun, electron, cathode

1891

D. Li, H.Q. Feng, D. Filippetto, M.J. Johnson, A.R. Lambert, T.H. Luo, C.E. Mitchell, J. Qiang, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells
LBNL, Berkeley, California, USA
H.Q. Feng
TUB, Beijing, People’s Republic of China

Funding: Director of Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
We report recent progress on the design of a normal conducting CW electron gun, APEX-II (Advanced Photo-injector EXperiment-II) at Lawrence Berkeley National Laboratory. APEX-II is an upgrade of the successful APEX gun and the LCLS-II (Linac Coherent Light Source-II) injector, aiming at applications for Free electron laser (FEL) such as LCLS-II High Energy upgrade, UED (Ultrafast Electron Diffraction) and UEM (Ultrafast Electron Microscopy). The APEX-II adopted a two-cell cavity design with resonant frequency of 162.5 MHz. The APEX-II gun is targeting to achieve exceeding 30 MV/m of launch gradient at the cathode and output energy above 1.5 MeV with transverse emittance of 0.1 um at 100 pC. Advanced MOGA optimization technique has been used for both the RF cavity design and extensive beam dynamics studies using APEX-like and LCLS-II like injector layout. Detailed RF designs, beam dynamics studies, preliminary engineering design and FEA analysis will be presented, with cavity features that were demonstrated to be crucial in the operation of the APEX gun.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB097

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS024

Design of a Full C-Band Injector for Ultra-High Brightness Electron Beam

gun, emittance, cathode, klystron

1979

D. Alesini, F. Cardelli, G. Castorina, M. Croia, M. Diomede, M. Ferrario, A. Gallo, A. Giribono, B. Spataro, C. Vaccarezza, A. Vannozzi
INFN/LNF, Frascati (Roma), Italy

High gradient rf photo-injectors have been a key development to enable several applications of high quality electron beams. They allow the generation of beams with very high peak current and low transverse emittance, satisfying the tight demands for free-electron lasers, energy recovery linacs, Compton/Thomson sources and high-energy linear colliders. In the paper we present the design of a new full C-band RF photo-injector recently developed in the framework of the XLS-Compact Light design study and of the EuPRAXIA@SPARC_LAB proposal. It allows to reach extremely good beam performances in terms of beam emittance (at the level of few hundreds nm), energy spread and peak current. The photo-injector is based on a very high gradient (>200 MV/m) ultra-fast (RF pulses <200 ns) C-band RF gun, followed by two C band TW structures. Different types of couplers for the 1.6 cell RF gun have been considered and also a new compact low pulsed heating coupler working on the TM020 mode on the full cell has been proposed. In the paper we report the design criteria of the gun, the powering system, and the results of the beam dynamics simulations. We also discuss the case of 1 kHz repetition rate.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS024

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS047

Improvement of 6D Brightness by a 1.4-cell Photocathode RF Gun for MeV Ultrafast Electron Diffraction

gun, emittance, electron, cathode

2033

Y. Song
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
K. Fan, C.-Y. Tsai, Y.T. Yang
HUST, Wuhan, People’s Republic of China
J. Yang
ISIR, Osaka, Japan

Recent research indicates that ultrafast electron diffraction and microscopy (UED/M) have unprecedented potential in probing ultrafast dynamic processes, especially in organic and biological materials. However, reaching the required brightness while maintaining high spatiotemporal resolution requires new design of electron source. In order to produce ultrashort electron beam with extreme high brightness, a 1.4-cell RF gun is being developed to reach higher acceleration gradient near the photocathode and thus suppress the space charge effect in the low energy region. Simulation of the 1.4-cell RF photocathode gun shows considerable improvement in bunch length, emittance and energy spread, which all lead to better temporal and spatial resolution comparing to traditional 1.6-cell RF photocathode gun. The results demonstrate the feasibility of sub-ps temporal resolution with normalized emittance less than 0.1 πmm·mrad while maintaining 1 pC electron pulse.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS047

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paper received ※ 24 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS076

RF Design of APEX2 Cavities

gun, cavity, cathode, electron

2094

T.H. Luo, H.Q. Feng, D. Filippetto, M.J. Johnson, A.R. Lambert, D. Li, C.E. Mitchell, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells
LBNL, Berkeley, California, USA
H.Q. Feng
TUB, Beijing, People’s Republic of China

Funding: Director of Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
APEX2 is a proposed high repetition rate, high brightness electron source based on CW normal conducting RF cavities, aiming to further extend the brightness performance for FEL and UED/UEM beyond APEX. APEX2 consists of two cavities, one gun cavity for generating photo-electrons and one following cavity for beam energy boosting. In this paper, we present the RF design of the APEX2 cavities. The design has considered both beam dynamics requirements and engineering feasibility. A novel geometry optimization method with Genetic Algorithm has been implemented in the design procedure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS076

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS111

Study on Improving Durability of Cs-Te Photocathode for an RF-gun

cathode, gun, electron, vacuum

2182

T. Tamba, J. Miyamatsu, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

At Waseda University, we have been studying for high quality electron beam generation using 1.6 cell Cs-Te photocathode rf-gun. We use photocathode as the electron source, which can generate high- quality electron beam such as low emittance, and short bunch. The performance of photocathode is evaluated mainly in terms of quantum efficiency (Q.E.) and lifetime. Cs-Te photocathode used in the rf-gun is known for high Q.E. about 10% with UV light and relatively longer lifetime among semiconductor photocathodes. Since it is a hard environment for photocathode inside the gun, it is necessary to replace the photocathode every several months. In other words, in order to achieve long-term operation of rf-gun, it is necessary to find highly durable photocathode recipe. It has been reported that the Cs-Te photocathode by co-evaporation can produce a photocathode having a longer lifetime as compared with the sequential evaporation. Moreover, we have done studies to improve lifetime and durability of Cs-Te photocathode by coating the cathode surface with CsBr thin film. In this conference, we report the evaluation results of Cs-Te photocathode by co-evaporation, CsBr coating and future prospects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS111

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP022

Design and Construction of the CERN SPS Extraction Protection Elements for LIU

extraction, vacuum, simulation, quadrupole

2359

B. Balhan, C. Baud, J.C.C.M. Borburgh, M.A. Fraser, M. Hourican, L.O. Jorat, F.-X. Nuiry, S. Pianese
CERN, Geneva, Switzerland

At CERN, the SPS synchrotron is equipped with two fast extraction channels towards the LHC. As a part of the LHC injector upgrade project (LIU), the protection devices upstream of the septa in both extraction channels will be upgraded. Various failure scenarios have been studied and presented in the past, but the definitive approach for the equipment protection upgrade for each channel has now been determined. This paper describes the consequences of the most significant failure scenarios and the impact of the heat deposition in the diluter. The resulting material stresses are evaluated. The detailed layout for the extraction protection equipment for each extraction channel is outlined. The final layout consists of a extended diluter in Long Straight Section (LSS) 6 (TPSG6) and the installation of an additional movable absorber (TPSC4) upstream of the quadrupole in front of the existing protection equipment in LSS 4. The detailed mechanical design of the TPSC4 and the construction status of both TPSC4 and TPSG6 are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP022

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW022

A Numerical Analysis to Choose the Most Performing Optical Transition Radiation Screen

target, electron, radiation, site

2518

F. Cioeta, D. Alesini, A. Variola
INFN/LNF, Frascati (Roma), Italy
M. Ciambrella, A. Mostacci
Sapienza University of Rome, Rome, Italy
D. Cortis, M. Marongiu, V. Pettinacci
INFN-Roma, Roma, Italy

Optical Transition Radiation (OTR) screen represents the most appropriate instrument to measure and verify the characteristics of a beam spot size produced by a particle accelerator. In order to measure such beam properties, OTR screens have to sustain thermal and mechanical stresses due to the energy that several bunches deposit. Owing to these requirements, it is essential to identify the more suitable material to optimize the OTR dimensions and to get reliable measures from the diagnostic system. In this paper, we describe a numerical procedure to choose the most performing material taking into account the physical requirements of a multi-bunch high brightness. The procedure is based on a dedicated ANSYS script able to evaluate the fatigue life time of the material considering a high number of thermal cycles generated by several bunches. The main characteristic of this script is the capability to simulate the real thermal and mechanical effect on the target that the hitting particle beam produces. The numerical procedure has been applied to compare the performance of three relevant materials-Aluminium, Silicon and Graphite simulating a beam hitting with well-known parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW022

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPRB024

Low Power RF Test of a Quadrupole-free X-Band Mode Launcher for High Brightness Applications

GUI, quadrupole, simulation, electron

2856

G. Torrisi, L. Celona, S. Gammino, O. Leonardi, G. Sorbello
INFN/LNS, Catania, Italy
G. Castorina
Sapienza University of Rome, Rome, Italy
V.A. Dolgashev
SLAC, Menlo Park, California, USA
L. Faillace
INFN-Milano, Milano, Italy
G.S. Mauro
INFN/LNL, Legnaro (PD), Italy
G. Sorbello
University of Catania, Catania, Italy
B. Spataro
INFN/LNF, Frascati, Italy

In this work we present the low power RF characterization of a novel TM01 X-band mode launcher for the new generation of high brightness RF photo-injectors. The proposed mode launcher exploits a fourfold symmetry which minimizes both the dipole and the quadrupole fields in order to mitigate the emittance growth in the early stages of the acceleration process. Two identical aluminum mode launchers have been assembled and measured in back-to-back configurations for three different central waveguide lengths. From the back-to-back results we infer the performance of each mode launcher. The low power RF test, performed at the Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud (INFN-LNS), validate both the numerical simulations and the quality of fabrication. An oxygen-free high-conductivity copper version of the device is being manufactured for high power and ultra high vacuum tests that are planned to be conducted at SLAC

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB024

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paper received ※ 09 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPRB072

Ultra-High Gradient Short RF Pulse Gun

gun, electron, cathode, emittance

2987

S.P. Antipov, P.V. Avrakhov, S.V. Kuzikov, A. Liu
Euclid TechLabs, LLC, Solon, Ohio, USA
G. Ha, J.G. Power
ANL, Argonne, Illinois, USA

Funding: DOE SBIR DE-SC0018709
High brightness beams enable novel applications like x-ray free electron lasers and ultrafast electron microscopes. High brightness beams essentially consist of a large number of electrons in a small phase space volume, i.e. a high peak current. When such beams are generated from the cathode, there is a strong space charge force, which elongates the bunch and reduces its brightness. An optimal solution is to raise the accelerating voltage in the gun. However, the maximum gradient is limited by the effects of RF breakdown. The probability of RF breakdown is reduced as the RF pulse length decreases. We present a development of an electron photoinjector operating with short RF pulse, 10 ns scale. We have designed an X-band gun including the RF design, beam quality optimization, and engineering. The gun will be fed by 10 ns, 300 MW RF pulse generated at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. We also manufactured an aluminum prototype and measured its microwave properties, most importantly, fill time. The proposed high brightness beam source can be used as the main beam in wakefield accelerators. It will find commercial applications in ultrafast electron diffraction and microscopy systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB072

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paper received ※ 21 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPTS047

Space Charge Driven Resonances in the CERN PS

resonance, space-charge, simulation, lattice

3216

F. Asvesta
NTUA, Athens, Greece
H. Bartosik, A. Huschauer, Y. Papaphilippou
CERN, Geneva, Switzerland

In the CERN Proton Synchrotron space charge driven resonances are excited around the operational working point due to the periodicity of the optics functions. In this paper, the resonances are studied using analytical methods, i.e. the evaluation of the resonance driving terms connected to the space charge potential of Gaussian distributions. Furthermore, the resonances are characterized in measurements and simulations for various beams. The beams considered are different in terms of brightness, in order to study the dependence of the resonance strength on the space charge force.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS047

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paper received ※ 17 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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