IPAC2018 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOXGB2	ARIEL at TRIUMF: Science and Technology	TRIUMF, ISAC, target, cyclotron	6
	J.A. Bagger, F. Ames, Y. Bylinskii, A. Gottberg, O.K. Kester, S.R. Koscielniak, R.E. Laxdal, M. Marchetto, P. Schaffer TRIUMF, Vancouver, Canada M. Hayashi TRIUMF Innovations Inc., Vancouver, Canada
	The Advanced Rare Isotope Laboratory (ARIEL) is TRIUMF's flagship project to create isotopes for science, medicine and business. ARIEL will triple TRIUMF's rare isotope beam capability, enabling more and new experiments in materials science, nuclear physics, nuclear astrophysics, and fundamental symmetries, as well as the development of new isotopes for the life sciences. Beams from ARIEL's new 35 MeV, 100kW electron linear accelerator and from TRIUMF's original 500 MeV cyclotron will enable breakthrough experiments with the laboratory's suite of world-class experiments at the Isotope Separator and Accelerator (ISAC) facility. This invited talk will present an overview of TRIUMF, the ARIEL project, and the exciting science they enable.
	Slides MOXGB2 [65.004 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOXGB2
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MOYGB1	Status and Future Strategy for Advanced High Power Microwave Sources for Accelerators	klystron, electron, cavity, operation	12
	F. Gerigk CERN, Geneva, Switzerland
	The need for more energy efficient high power microwave devices for accelerator applications continues to increase. This is important for development of cost effective accelerator designs that are coming up in the near future. Efforts are already in place to design new devices that could stretch the limits of RF power conversion to the highest levels possible. Devices including new technologies and design innovations like multi beam, increased number of cavities designs are being considered. Advances in the application of solid state amplifiers to accelerators are also being realized. This invited talk will cover the recent advances and status of such efforts. It will discuss future needs and a strategy for pursuing these efforts on a faster time scale for the benefit of the accelerator community.
	Slides MOYGB1 [11.575 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOYGB1
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MOYGB2	The LCLS-II: A High Power Upgrade to the LCLS	cavity, undulator, cryomodule, electron	18
	J.N. Galayda SLAC, Menlo Park, California, USA
	Funding: The work is supported by DOE under grant No. DE-AC02-76SF00515 The LCLS-II is an upgrade of the LCLS X-ray FEL based on a 4 GeV superconducting RF linac. The LCLS-II is designed to produce 100's of Watts of X-rays from 200 eV up to 5 keV. The linac uses 1.3 GHz 9-cell cavities processed using the N2-doping technique and will be the first large scale CW SCRF linac with a Q of roughly 3x10¹⁰ at a gradient of 16 MV/m. The injector which will be commissioned in spring 2018, is based on the normal conducting CW RF APEX gun developed at LBNL. The LCLS-II will have two undulators: the soft X-ray undulator is a 39 mm period hybrid PM with an adjustable vertical gap to cover the range from 200 eV to 1.5 keV and hard X-ray undulator is a novel adjustable horizontal gap hybrid PM undulator with 26 mm period to generate vertically polarized X-rays from 1 to 5 keV. The talk will review the performance goals as well as the hardware fabrication.
	Slides MOYGB2 [11.367 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOYGB2
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MOZGBD5	A Proposal for Coherent Hard X-Ray Generation Based on Two-Stage EEHG	FEL, electron, laser, radiation	38
	Z.T. Zhao, J.H. Chen, C. Feng, Z. Wang, K.Q. Zhang SINAP, Shanghai, People's Republic of China
	A two stage echo-enabled harmonic generation (EEHG) scheme to produce coherent hard X-rays is presented. Electron bunchs of quite different lengths are separately used in each stage of EEHG and a monochromator is employed to purify the radiation from the first stage for seeding the second one. Theoretical analysis and 3D simulations show that the proposed scheme can generate fully coherent hard X-ray pulses directly from a conventional UV seed laser.
	Slides MOZGBD5 [7.330 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBD5
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MOZGBF4	Evolution of the Superconducting Linac Output Energy at the Spallation Neutron Source	cavity, cryomodule, operation, SRF	73
	S.-H. Kim, D.E. Anderson, M.T. Crofford, M. Doleans, J. Galambos, S.W. Gold, M.P. Howell, M.A. Plum, D.J. Vandygriff ORNL, Oak Ridge, Tennessee, USA R. Afanador, D.L. Barnhart, B. DeGraff, J.D. Mammosser, C.J. McMahan, T.S. Neustadt, C.C. Peters, J. Saunders, D.M. Vandygriff ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. The SNS linac output energy has increased since the start of neutron production in FY2007. The various improvements that contributed to the increase of the linac output energy are LLRF/control system improvement, high voltage converter modulator system improvement, high-power RF system improvement, cryomodule repairs, spare cryomodule development and accelerating gradient improvement through in-situ plasma processing. In this paper, the history of the SNS SCL output energy is reported, and plans for the near-term future and for the Proton Power Upgrade (PPU) project are also presented.
	Slides MOZGBF4 [34.185 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOZGBF4
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MOPMF001	Bunch Schedules for the FCC-ee Pre-injector	injection, collider, booster, positron	79
	S. Ogur, K. Oide, Y. Papaphilippou, F. Zimmermann CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	The latest design of the Future Circular electron-positron Collider (FCC-ee) foresees a luminosity per interaction point above 2.0·10³⁶/cm²/s for operation at the Z pole. The filling from zero current occurs in collision to profit from the bunch lengthening due to beamstrahlung (so-called bootstrapping). At any time when new e^- and e⁺ buckets or bunchlets are injected into the collider, they will collide instantly. For this reason, we may provide the charge in each injected bunch in a way to pre-compensate for anticipated beam loss, and to reach the target luminosity as soon as possible after the first injection. In this way, we optimise the injection schedules for Z-mode so as to reach the peak luminosity in less than 20 minutes by interleaved injection of the two species at some portion of full bucket charge. Filling from zero the injector should allow accumulating 1.7·10¹¹ particles in one collider bucket within at least 10 injections, assuming a total transmission above 80%. In steady-state operation, the injector chain continually produces and accelerates lower bunch charges so as to maintain nearly constant bunch currents and constant peak luminosity.
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MOPMF005	Beam Formation in the Alternative JLEIC Ion Complex	booster, collider, injection, proton	91
	B. Mustapha, J.L. Martinez Marin ANL, Argonne, USA Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy / ONP, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The proposed alternative design approach for the JLab-EIC (JLEIC) ion complex uses a more compact linac and pre-booster, and consolidates the electron storage ring (e-ring) as a large booster for the ions. Following a parameter study* showing the feasibility of this alternative design approach, we have adapted the e-ring lattice by adding RF sections to accelerate ion beams*. In this study, we focus on the beam formation for protons and lead ions from the linac to the pre-booster, then into the e-ring until injection to the ion collider ring. Effects such as space charge, intra-beam scattering and the need for beam cooling will determine the total accumulated charge in each ring and the time required from injection from the injector linac to collision in the collider ring. B. Mustapha et al, Proceedings of NAPAC-2016, October 9-14, Chicago, IL. ** B. Mustapha et al, Proceedings of IPAC-2017, May 14-19, Copenhagen, Denmark.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF005
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MOPMF034	Layout and Performance of the FCC-ee Pre-Injector Chain	emittance, damping, injection, cavity	169
	S. Ogur, T.K. Charles, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia I. Chaikovska, R. Chehab LAL, Orsay, France K. Furukawa, N. Iida, T. Kamitani, F. Miyahara KEK, Ibaraki, Japan E.V. Ozcan Bogazici University, Bebek / Istanbul, Turkey S.M. Polozov MEPhI, Moscow, Russia
	The Future Circular e⁺e⁻ Collider pre-injector chain consists of a 6 GeV S-Band linac, a damping ring at 1.54 GeV and pre-booster ring to reach 20 GeV for injection to the main booster. The electron and positron beams use the same accelerator chain alternatively. The e⁺ beam is generated from a novel low level RF-gun providing 6.5 nC charge at 11 MeV with 0.5 micron geometric emittance. The e⁺ beam is produced by the impact of a 4.46 GeV e^- beam onto a hybrid target, accelerated in the linac up to 1.54 GeV, and injected to the damping ring for emittance cooling. Simulations on the performance of the DR are presented for reaching the required equilibrium emittances at the required damping time. As an alternative option, a 20 GeV linac is considered utilising C-Band cavities and simulations studies have been undertaken regarding the beam transport and transmission efficiency up to that energy.
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MOPMF055	Update of the CLIC Positron Source	positron, target, electron, simulation	236
	Y. Han, L. Ma SDU, Shandong, People's Republic of China C. Bayar Ankara University, Faculty of Sciences, Ankara, Turkey S. Döbert, A. Latina, D. Schulte CERN, Geneva, Switzerland
	The baseline positron source of CLIC has been optimised for the 3 TeV c.o.m. energy. Now the first stage of the CLIC is proposed to be at 380 GeV. Recently, the positron transmission efficiency from the tungsten target to the damping rings injection has been improved by 2.5 times. This opened the possibility for an optimisation of the whole positron source, comprising the injector linacs, aimed at improving its performance and its overall power efficiency. In this paper the key parameters of the positron source, which include the current and the energy of the primary electron beam, the thickness of the crystal and amorphous tungsten targets, the distance between the two targets, the adiabatic matching device (AMD) and pre-injector linacs, are optimized to improve the overall power efficiency.
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MOPMF073	Rejuvenation of 7-Gev SuperKEKB Injector Linac	positron, electron, emittance, injection	300
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimura, T. Suwada, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou KEK, Ibaraki, Japan
	KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It was upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of flavor physics beyond the standard model of elementary particle physics. SuperKEKB energy-asymmetric electron-positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. The electron beam is generated by a new type of RF gun, that provides a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 μm to 10 μm in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The summary of the rejuvenation is reported.
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MOPMF074	Beam Phase Space Jitter and Effective Emittance for SuperKEKB Injector Linac	emittance, target, electron, positron	304
	Y. Seimiya, N. Iida, T. Kamitani, M. Satoh KEK, Ibaraki, Japan
	In SuperKEKB linac, stable high charged low emittance beam is necessary. Transported beam to SuperKEKB Main Ring (MR) must be stable to the extent that the beam can be injected inside MR acceptance. SuperKEKB requirement must be satisfied for emittance including beam phase space jitter, called as effective emittance. Large amplitude beam position jitter has been measured at linac end. We evaluated that the effect of the beam position jitter on effective emittance and investigated the source of the beam phase space jitter.
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MOPMF076	Energy Spread Compensation in Arbitrary Format Multi-Bunch Acceleration With Standing Wave and Traveling Wave Accelerators	beam-loading, acceleration, positron, cavity	307
	M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan
	In the E-driven ILC (International Linear Collider) positron source, the beam is generated and accelerated in a multi-bunch format with mini-trains. The macro-pulse contains 2 to 8 mini-trains with several train gaps, because the pulse format is a copy of a part of the bunch storage pattern in DR (Damping Ring). This pulse format causes a variation of the accelerator field in the pulse due to the transient beam loading and an intensity fluctuation of captured positron. In this article, we discuss the compensation of the energy spread of such beam in standing wave and traveling wave accelerators. For standing wave accelerator, it can be compensated by switching input RF at appropriate timings. For traveling wave accelerator, it can be compensated by amplitude modulation of the input RF.
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MOPMF084	The Progress of CEPC Positron Source Design	positron, target, electron, collider	319
	C. Meng, X.P. Li, G. Pei, J.R. Zhang IHEP, Beijing, People's Republic of China
	Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory. The injector is composed of 10 GeV linac and 120 GeV booster. The linac of CEPC is a normal conducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV and repetition frequency in 100 Hz. The positron source of CEPC is composed of target, flux concentrator, pre-accelerating section and beam separation system. The detailed design of each section of positron source will be presented and discussed, meanwhile the start-to-end dynamic simulation results will be presented also in this paper.
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MOPMK015	Development of a Bunched-Beam Electron Cooler for the Jefferson Lab Electron-Ion Collider	electron, kicker, gun, cathode	382
	S.V. Benson, Y.S. Derbenev, D. Douglas, F.E. Hannon, A. Hutton, R. Li, R.A. Rimmer, Y. Roblin, C. Tennant, H. Wang, H. Zhang, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177. Jefferson Lab is in the process of designing an electron-ion collider with unprecedented luminosity at a 65 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. We will present a new design for a Circulator Cooler Ring for bunched-beam electron cooling. This requires the generation and transport of very high-charge magnetized bunches, acceleration of the bunches in an energy recovery linac, and transfer of these bunches to a circulating ring that passes the bunches 11 times through the proton or ion beam inside cooling solenoids. This design requires the suppression of the effects of space charge and coherent synchrotron radiation using shielding and RF compensation.
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MOPML014	Status of the Commissioning of the LIGHT Prototype	DTL, MMI, rfq, proton	425
	A. Degiovanni, J. Adam, D. Aguilera Murciano, S. Ballestrero, A. Benot-Morell, R. Bonomi, F.C.M. Cabaleiro Magallanes, M. Caldara, G. D'Auria, G. De Michele, M. Esposito, S. Fanella, D. Fazio, D.A. Fink, Y. Fusco, M. Gonzalez, P. Gradassi, A. Jeff, L. Kobzeva, G. Levy, G. Magrin, A. Marraffa, A. Milla, R. Moser, P. Nadig, G. Nuessle, A. Patino-Revuelta, T. Rutter, F. Salveter, A. Samoshkin, L. Wallet A.D.A.M. SA, Meyrin, Switzerland M. Cerv, V.A. Dimov, L.S. Esposito, S. H. Gibson, M. Giunta, Ye. Ivanisenko, V. F. Khan, S. Magnoni, C. Mellace, J.L. Navarro Quirante, H. Pavetits, PPA. Paz Neira, P. Stabile, K. Stachyra, D. Ungaro, A. Valloni, C. Zannini AVO-ADAM, Meyrin, Switzerland
	The company A.D.A.M. (Application of Detectors and Accelerators to Medicine), a CERN spin-off, is working on the construction and testing of its first linear accelerator for medical application: LIGHT (Linac for Image-Guided Hadron Therapy). LIGHT is an innovative high frequency proton linac designed to accelerate proton beams up to 230 MeV for protontherapy applications. The LIGHT accelerator consists of three different linac sections: a 750 MHz Radio Frequency Quadrupole (RFQ) accelerating the beam up to 5 MeV; a 3 GHz Side Coupled Drift Tube Linac (SCDTL) up to 37.5 MeV; and a 3 GHz Cell Coupled Linac (CCL) section up to 230 MeV. The compact and modular design is based on cutting edge technologies developed for particle colliders and adapted to the needs of hadron therapy beams. A prototype of LIGHT is presently under commissioning at CERN. This paper describes the design aspects and the different stages of installation and commissioning of the LIGHT prototype with emphasis on beam tests results obtained during the past year at different energies.
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MOPML015	Simulations and Measurements of the CCL Modules of the LIGHT Accelerator	coupling, proton, GUI, cavity	429
	V. F. Khan, G. De Michele, S. Fanella, S. H. Gibson, Ye. Ivanisenko, C. Mellace, J.L. Navarro Quirante, C. Zannini AVO-ADAM, Meyrin, Switzerland M. Esposito, P. Gradassi CERN, Geneva, Switzerland
	A 230 MeV proton LINAC system for medical applications is being developed and commissioned for the LIGHT (Linac Image Guided Hadron Therapy) project by AVO-ADAM. The LINAC system consists of a 750 MHz RFQ (Radio frequency quadrupole) for the low energy proton acceleration, 2998 MHz SCDTL (Side Coupled Drift Tube Linacs) for the medium energy and 2998 MHz CCL (Coupled Cavity Linacs) for the high energy. In particular, the CCL accelerating modules are used in the energy range from 37.5 - 230 MeV. In this paper we discuss the 3D EM (electro-magnetic) simulation results and measurements of the CCL modules.
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MOPML017	Status and Development of the MYRRHA Injector	cavity, diagnostics, MMI, rfq	432
	D. Mäder, H. Höltermann, D. Koser, B. Koubek, K. Kümpel, P. Müller, U. Ratzinger, M. Schwarz, W. Schweizer BEVATECH, Frankfurt, Germany C. Angulo, J. Belmans, D. Davin, W. De Cock, P. Della Faille, F. Doucet, A. Gatera, Pompon, F.F. Pompon, D. Vandeplassche Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium M. Busch, H. Hähnel, H. Podlech IAP, Frankfurt am Main, Germany
	The MYRRHA project aims at coupling a cw 600 MeV, 4 mA proton linac with a sub-critical reactor as the very first prototype nuclear reactor to be driven by a particle accelerator (ADS). Among several applications, MYRRHA main objective is to demonstrate the principle of partitioning and transmutation (P&T) as a viable solution to drastically reduce the radiotoxicity of long-life nuclear waste. For this purpose, the linac needs an unprecedented level of reliability in terms of allowable beam trips. The normal conducting injector delivers 16.6 MeV protons to the superconducting main linac. The first section of the injector (up to 5.9 MeV) consists of an ECR source, a 4-Rod-RFQ and a rebunching line followed by 7 individual CH-type cavities. This entire section will be set up and operated by SCK·CEN in Louvain-la-Neuve, Belgium, for ample performance and reliability testing. The first CH cavity has been sent for power tests to IAP Frankfurt, Germany. The most recent status of all cavities, couplers and the beam diagnostics of the MYRRHA injector is presented in this paper.
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MOPML022	Development of Travelling Wave Accelerating Structure for a 10 MeV E-Linac	electron, bunching, radiation, simulation	443
	J.H. Yang, Y. Yang CIAE, Beijing, People's Republic of China G. Han China Institute of Atomic Energy, Beijing, People's Republic of China
	Electron irradiation processing is a vital application field of nuclear technology application. China Institute of Atomic Energy (CIAE) developed several 10 MeV high power electron irradiating accelerator successfully, promoting the development of high energy high power irradiating accelerator technology and electron irradiation processing in China. The paper introduced the development of a 10 MeV travelling wave accelerating tube. The tube operates at 2856 MHz in 2π/3 mode. The SUPERFISH and PARMELA are used for the physical design. Several methods are used for microwave parameter measurement and tuning. The high power test shows the beam energy is 10.3 MeV and average beam power is 24.3 kW.
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MOPML027	Status of Carbon Commissioning of the MedAustron Therapy Accelerator	MMI, synchrotron, ion-source, rfq	457
	C. Schmitzer, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, I. Strašík, A. Wastl EBG MedAustron, Wr. Neustadt, Austria L.C. Penescu Abstract Landscapes, Montpellier, France
	The MedAustron therapy accelerator is intended to treat cancer patients with proton and carbon beams of 62-252 MeV and 120-400 MeV respectively. The accelerator features three Supernanogan ECR ion sources, a 400 keV/u RFQ and a 7 MeV/u interdigital H-mode Linac. A middle energy beam transfer line also serves as injector into a 77m synchrotron from which the beam may be transferred to 4 different irradiation rooms, 3 of which are dedicated to medical treatment. The therapy accelerator is in clinical operation since end 2016 and is currently solely configured for the use of protons. The next clinical objective is to enable treatments using C⁶⁺ ions which triggered the carbon commissioning of the accelerator in 2017. This paper will discuss the latest results from carbon commissioning in the different sections of the accelerator, achieved efficiencies and outlook on future carbon activities.
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MOPML028	Accelerator Machines and Experimental Activities in the ENEA Frascati Particle Accelerators and Medical Application Laboratory	radiation, experiment, proton, electron	460
	M. Vadrucci, A. Ampollini, G. Bazzano, F. Borgognoni, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti, E. Trinca ENEA C.R. Frascati, Frascati (Roma), Italy
	Funding: Regione Lazio - TOP IMPLART Project In the ENEA Frascati research center the APAM (Particle Accelerators and Medical Application) laboratory is devoted to the development of particle accelerators for medical applications. Two main facilities are operational. The TOP-IMPLART proton accelerator is a pulsed fully linear machine aimed at active intensity modulated proton therapy with a final energy of 150 MeV. The machine offers two beam extraction points: one at 3-7 MeV, on a vertical line, and the other one at 35 MeV, the maximum energy currently available, with a pulse current up to 35 μA, on the horizontal line. The REX (Removable target Electron X-ray) source consists of an electron standing wave LINAC generating a beam in the energy range of 3 to 5 MeV with a pulsed current of 0.2 A. This source can generate Bremsstrahlung X-ray beams using suitable converters (Pb, W, Ta). This paper describes the experimental results of satellite activities performed in these facilities in the fields of biology, dosimetry, electronics, PIXE spectroscopy and preservation of cultural heritage manufacts.
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MOPML031	Highlights of Accelerator Activities in France on Behalf of the Accelerator Division of the French Physics Society	laser, proton, operation, electron	470
	J.-L. Revol ESRF, Grenoble, France S. Chel CEA/IRFU, Gif-sur-Yvette, France B. Cros CNRS LPGP Univ Paris Sud, Orsay, France N. Delerue LAL, Orsay, France E. Giguet ALSYOM, Versailles, France V. Le Flanchec CEA/DAM, Bruyères-le-Châtel, France L.S. Nadolski SOLEIL, Gif-sur-Yvette, France L. Perrot IPN, Orsay, France A. Savalle GANIL, Caen, France T. Thuillier LPSC, Grenoble Cedex, France
	The French Physical Society is a non-profit organization working to advance and diffuse the knowledge of physics. Its Accelerators division contributes to the promotion of accelerator activities in France. This paper presents the missions and actions of the division, high-lighting those concerning young scientists. A brief presentation of the laboratories, institutes, and facilities that are the main actors in the field is given. Significant ongoing and planned projects in France are described, including medical applications. Main French contributions in inter-national projects are then listed. Finally, cultural and technical relationships between industry and laboratories are discussed.
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MOPML032	Prospects for a Muon Spin Resonace Facility in the Fermilab MuCool Test Area	target, experiment, timing, resonance	474
	J.A. Johnstone, C. Johnstone Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Reserach Alliance, LLC under Contract no. DE-AC02-07CH11359 with the United States Department of Energy. This paper investigates the feasibility of re-purposing the MuCool Test Area beamline and experimental hall to support a Muon Spin Resonance Facility which would make it the only such facility in the US. This report reviews the basic muon production concepts as studied and operationally implemented at TRIUMF, PSI, and RAL and their application in the context of the MTA facility. Two scenarios were determined feasible. One, an initial minimal-shielding and capital-cost investment stage with a single secondary muon beamline that utilizes an existing primary beam absorber and, another, an upgraded stage, that implements an optimized production target, a proximate high-intensity absorber, and optimized secondary muon lines. A unique approach is proposed which chops or strips a macropulse of H⁻ beam into a micropulse substructure - a muon creation timing scheme - which allows Muon Spin Resonance experiments in a linac environment. With this timing scheme, and attention to target design and secondary beam collection, the MTA can host enabling and competitive Muon Spin Resonance experiments.
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MOPML033	Data Supply of Accelerator Devices - Data Management of Device Process Data at a Medical Accelerator	controls, database, operation, MMI	477
	M. Galonska, R. Cee, Th. Haberer, K. Höppner, J.M. Mosthaf, A. Peters, S. Scheloske, C. Schömers HIT, Heidelberg, Germany
	HIT is the first dedicated proton and carbon cancer therapy facility in Europe. It uses the full 3D intensity controlled raster scanning dose delivery method of pencil beams with ion beams of 48 - 430 MeV/u provided by a linac-synchrotron-system. Ion beams in this wide range of energies, different beam sizes, and intensities have to be provided by the control system to all treatment rooms at any time with high accuracy, stability, and reproducibility. This paper briefly reflects some aspects of the data supply, i. e. the settings of accelerator devices at a medical accelerator. This includes the generation of control data, storage, and data recovery routines, which have been developed at HIT in the recent years. That is in particular the management of verified therapy data and settings, which are stored in a non-volatile memory of the device controllers, and – as a backup – in a database and which are protected against unintended changes for safety reasons.
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MOPML043	High Gradient Performance of an S-Band Backward Traveling Wave Accelerating Structure for Medical Hadron Therapy Accelerators	proton, cavity, radiation, accelerating-gradient	491
	A. Vnuchenko, C. Blanch Gutiérrez, D. Esperante Pereira IFIC, Valencia, Spain S. Benedetti, N. Catalán Lasheras, A. Grudiev, B. Koubek, G. McMonagle, I. Syratchev, B.J. Woolley, W. Wuensch CERN, Geneva, Switzerland A. Faus-Golfe LAL, Orsay, France T.G. Lucas, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia S. Pitman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	The high-gradient performance of an accelerating structure prototype for a medical proton linac is presented. The structure was designed and built using technology developed by the CLIC collaboration and the target application is the TULIP (Turning Linac for Proton therapy) proposal developed by the TERA foundation. The special feature of this design is to produce gradient of more than 50 MV /m in low-β accelerating structures (v/c=0.38). The structure was tested in an S-band test stand at CERN. During the tests, the structure reached over above 60 MV/m at 1.2 μs pulse length and breakdown rate of about 5x10^-6 bpp. The results presented include ultimate performance, long term behaviour and measurements that can guide future optimization.
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MOPML044	Start-to-End Beam Dynamic Simulations for PRAE	gun, emittance, laser, solenoid	495
	A. Vnuchenko IFIC, Valencia, Spain C. Bruni, M. El Khaldi, A. Faus-Golfe, P. Lepercq, C. Vallerand LAL, Orsay, France A. Latina CERN, Geneva, Switzerland
	The PRAE project (Platform for Research and Applications with Electrons) aims at creating a multidisciplinary R&D facility in the Orsay campus gathering various scientific communities involved in radiobiology, subatomic physics, instrumentation and particle accelerators around an electron accelerator delivering a high-performance beam with energy up to 70 MeV and later 140 MeV, in order to perform a series of unique measurements and future challenging R&D. In this paper we report the first start-to-end simulations from the RF gun, going through the linac and finally to the different experimental platforms. The beam dynamics simulations have been performed using a concatenation of codes. In particular for the linac the RF-Track code recently developed at CERN will be used and benchmarked. The different working points have been analysed in order to minimise the transverse emittance and the beam energy spread including space charge effects at low electron energies.
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MOPML052	The Path to Compact, Efficient Solid-State Transistor-Driven Accelerators	cavity, electron, impedance, simulation	520
	D.C. Nguyen, C.E. Buechler, G.E. Dale, R.L. Fleming, M.A. Holloway, J.W. Lewellen, D. Patrick LANL, Los Alamos, New Mexico, USA V.A. Dolgashev, E.N. Jongewaard, E.A. Nanni, J. Neilson, A.V. Sy, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: Research presented in this work is supported by (LANL) Laboratory Directed Research and Development 20170521ER and by (SLAC) Department of Energy contract DE-AC02-76SF00515. Small, lightweight, few-MeV electron accelerators that can operate with low-voltage power sources, e.g., solid-state transistors running on 50 VDC, instead of high-voltage klystrons, will provide a new tool to enhance existing applications of accelerators as well as to initiate new ones. Recent advances in gallium nitride (GaN) semiconductor technologies * have resulted in a new class of high-power RF solid-state devices called high-electron mobility transistors (HEMTs). These HEMTs are capable of generating a few hundred watts at S-, C- and X-bands at 10% duty factor. We have characterized a number of GaN HEMTs and verified they have suitable RF characteristics to power accelerator cavities *. We have measured energy gain as a function of RF power in a single low-beta C-band cavity. The HEMT powered RF accelerators will be compact and efficient, and they can operate off the low-voltage DC power buses or batteries. These all-solid-state accelerators are also more robust, less likely to fail, and are easier to maintain and operate. In this poster, we present the design of a low-beta, 5.1-GHz cavity and beam dynamics simulations showing continuous energy gain in a ten-cavity C-band prototype. See for example, http://www.wolfspeed.com/downloads/dl/file/id/463/product/174/cghv59350.pdf ** J.W. Lewellen et al., Proceedings of LINAC2016, Paper MO3A03
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MOPML055	Preliminary Physics Design of a Linac with the Variable Energy for Industrial Applications	electron, gun, beam-loading, simulation	530
	Zh. X. Tang USTC, Hefei, Anhui, People's Republic of China L. Wang, D.R. Xu USTC/NSRL, Hefei, Anhui, People's Republic of China
	This paper describes the physics design of a S-band (2856 MHz) linear accelerator (linac) with variable energy tuning. The system consists of a DC gun for generating electron, prebuncher for velocity modulation and two travelling wave (TW) accelerating sections for acceleration. The accelerating structure is a 2'Ð/3 mode constant gradient TW structure, which comprises TW buncher cells, followed by uniform cells. The structure is designed to accelerate 45 keV electron beam from the electron gun to 3.2 MeV, and then 10 MeV. An important feature of the TW linac is that the RF output power of the first linac is as the RF input power of the second linac. Three dimensional transient simulations of the accelerating structure along with the input and output couplers have been performed to explicitly demonstrate this feature. Beam dynamics is performed to calculate the beam parameter.
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MOPML058	Comparison of Water Absorbed Dose for Photons of Linac and Traceability System for Radiotherapy in China	photon, controls, radiation, electron	537
	K. Wang, S. Jin, Z. Wang, J. Zhang National Institute of Metrology, Beijing, People's Republic of China
	National Institute of Metrology (NIM) developed the standards of the absorbed dose to water for high-energy photon and electron beams, to support the PSDL and SSDL calibration capability in China. After the measurement of absorbed dose to water for 6, 10, and 25 MV photons of linac, NIM took part the BIPM. RI(I).K6 comparison with the Bureau International des Poids et Mesures (BIPM). The tissue phantom ratio (TPR_20,10) of 6MV and 10MV photons were measured by IBA CC13 chamber and Keithley 6517B with different output dose of the Linac, and also calculated by the dose ratio (D₂0⁄D₁0) with the formula in IAEA TRS-398 report. TPR_20,10 measured directly is 0.3% larger than calculated by the dose ratio D₂0⁄D₁0 . The absorbed dose to water is measured by water calorimeter with the combined standard uncertainty of 0.35%. The discrepancy of absorbed dose to water measured separately by open and sealed vessel is 0.2% at 10MV. The K6 comparison was done, the results reported as ratios of the NIM and the BIPM evaluations (and with the combined standard uncertainties given in parentheses), are 0.9917(60) at 6 MV, and 0.9941(59) at 10 MV. The quality correction factor KQ of usual used chamber was measure directly, and it is 0.3%~0.7% smaller than the data in the IAEA TRS-398 report. The typical chamber-to-chamber variations of the dose obtained with the IAEA TRS-277, TRS-398 and AAPM TG-51 were between 0.2% and 1.0% for the different photon beams. The variations of the dose obtained with IAEA TRS-398 and chambers calibrated directly by megavoltage photons were between 0.1% to 0.8%. The new standard can achieve the traceability of water absorbed dose for MV photons and will significantly reduce the uncertainty of ion chamber calibrations for Chinese radiotherapy centers.
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MOPML067	9/6 MeV European S-band Linac Structure for Container Inspection System at RTX and KAERI	electron, coupling, bunching, gun	560
	P. Buaphad, H.D. Park, S. Song RTX, Daejeon, Republic of Korea P. Buaphad, Y. Joo University of Science and Technology of Korea (UST), Daejeon, Republic of Korea P. Buaphad, S.C. Cha, Y. Joo, Y. Kim, H.R. Lee KAERI, Jeongeup-si, Republic of Korea
	Recently, demands on low energy electron linear accelerators (linacs) for industrial applications are rapidly growing. Their beam energies are lower than 20 MeV, and they require a compact, cheap, and stable accelerator system. For the Container Inspection System (CIS), KAERI successfully developed a 9/6 MeV American S-band (= 2856 MHz) linac with a 5 MW klystron in 2013. To reduce the cost of the RF source, recently, KAERI and RTX also have been developing another 9/6 MeV European S-band (= 2998 MHz) linac by using a magnetron with a lower RF power of about 3.1 MW. Its accelerating structure is designed to be operated in π/2 mode by coupling 13 accelerating cells together through 12 side-coupling cells. The CST Microwave Studio is used for electromagnetic simulations and optimization of the accelerating structure. After various optimizations, a shunt impedance of 84 MΩ/m is obtained at π/2 mode frequency of 2998.31 MHz. In this paper, we describe design concept, optimization, and RF measurement of the new 9/6 MeV European S-band linac structure. Then, we compare it with our old American S-band linac structure.
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TUYGBE2	CBETA, the 4-Turn ERL with SRF and Single Return Loop	electron, gun, SRF, cryomodule	635
	G.H. Hoffstaetter, N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte BNL, Upton, Long Island, New York, USA D. Douglas JLab, Newport News, Virginia, USA J.K. Jones Cockcroft Institute, Warrington, Cheshire, United Kingdom D. Jusic Cornell University, Ithaca, New York, USA D.J. Kelliher STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom B.C. Kuske, M. McAteer, J. Völker HZB, Berlin, Germany
	Funding: Supported by NSF award DMR-0807731, DOE grant DE-AC02-76SF00515, and NYSERDA. A collaboration between Cornell University and Brookhaven National Laboratory has designed and is constructing CBETA, the Cornell-BNL ERL Test Accelerator on the Cornell campus. The ERL technology that has been prototyped at Cornell for many years is being used for this new accelerator, including a DC electron source and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current linac cryomodule optimized for ERLs, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams. BNL has designed multi-turn ERLs for several purpose, dominantly for the electron beam of eRHIC, its Electron Ion Collider (EIC) project and for the associated fast electron cooling system. Also in JLEIC, the EIC designed at JLAB, an ERL is envisioned to be used for electron cooling. The number of transport lines in an ERL is minimized by using return arcs that are comprised of a Fixed Field Alternating-gradient (FFA) design. This technique will be tested in CBETA, which has a single return for the 4-beam energies with strongly-focusing permanent magnets of Halbach type. The high-brightness beam with 150~MeV and up to 40~mA will have applications beyond accelerator research, in industry, in nuclear physics, and in X-ray science. Low current electron beam has already been sent through the most relevant parts of CBETA, from the DC gun through both cryomodules, through one of the 8 similar separator lines, and through one of the 27 similar FFA structures. Further construction is envisioned to lead to a commissioning start for the full system early in 2019.
	Slides TUYGBE2 [17.343 MB]
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TUPAF001	Requirements for the Cryogenic Refrigerator and the He Distribution System for the MYRRHA 100 Mev Accelerator	cryogenics, cavity, cryomodule, operation	655
	T. Junquera Accelerators and Cryogenic Systems, Orsay, France C. Angulo Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium D. Vandeplassche SCK•CEN, Mol, Belgium
	MYRRHA is an ADS demonstrator for the long-lived radioactive waste transmutation. It is composed of a High Energy CW Linac Accelerator (600 MeV - 4mA) coupled to a Subcritical Reactor of 100 MW thermal power. The main challenge of the Linac is a very high reliability performance to limit stress and long restart procedures of the reactor. Within the MYRRHA project phased approach for the construction, a 100 MeV-4 mA Linac (Injector up to 17 MeV and SC Linac between 17 MeV and 100 MeV) will be constructed in the Phase 1, covering 2016-2024. The SC Linac is composed of 58 Single-Spoke SC cavities, housed in 29 cryomodules. The cavities operates at 352 MHz, in a superfluid Helium bath at 2K. In this paper, the requirements for the Linac Cryogenic System are presented. The analysis of high thermal loads induced by the CW mode operation of cavities, leads to a Cryogenic Refrigerator with a power of 2700 W (equiv. power capacity at 4.5 K). Each cryomodule is connected through a dedicated Valve Box to the Helium transfer line running along the Linac tunnel. A description of the cryogenic system features and initial models of the tunnel and associated buildings are presented.
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TUPAF002	Beam Commissioning of the 750 MHz Proton RFQ for the LIGHT Prototype	rfq, MMI, emittance, diagnostics	658
	V.A. Dimov, M. Caldara, A. Degiovanni, L.S. Esposito, D.A. Fink, M. Giunta, A. Jeff, A. Valloni AVO-ADAM, Meyrin, Switzerland A.M. Lombardi, S.J. Mathot, M. Vretenar CERN, Geneva, Switzerland
	ADAM (Application of Detectors and Accelerators to Medicine), a CERN spin-off company, is developing the Linac for Image Guided Hadron Therapy, LIGHT, which will accelerate proton beams up to 230 MeV. The design of the linac will allow fast intensity and energy modulation for pencil-beam scanning during cancer treatment. The linac consists of a 40 keV Proton Injector; a 750 MHz Radio Frequency Quadrupole (RFQ) accelerating the proton beam up to 5 MeV; a 3 GHz Side Coupled Drift Tube Linac (SCDTL) up to 37.5 MeV; and a 3 GHz Cell Coupled Linac (CCL) section up to 230 MeV. A prototype of LIGHT is being commissioned progressively with the installation of the accelerating structures at a CERN site. The beam commissioning of the RFQ, which was designed and built by CERN, was completed in 2017 using a movable beam diagnostic test bench with various instruments. This paper reports on the RFQ commissioning strategy and the results of the beam measurements.
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TUPAF003	Integrated Prototyping in View of the 100 MeV Linac for Myrrha Phase 1	cryomodule, cavity, controls, target	661
	D. Vandeplassche, J. Belmans SCK•CEN, Mol, Belgium C. Angulo, D. Davin, W. De Cock, P. Della Faille, F. Doucet, A. Gatera, Pompon, F.F. Pompon Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium D. Bondoux, F. Bouly LPSC, Grenoble Cedex, France H. Höltermann, D. Mäder BEVATECH, Frankfurt, Germany C. Joly, G. Olry, H. Saugnac IPN, Orsay, France M. Loiselet, N. Postiau, L. Standaert UCL, Louvain-la-Neuve, Belgium H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: Work partially supported by the European Commission H2020 programme MYRTE #662186 The MYRRHA project borne by SCK•CEN, the Belgian Nuclear Research Centre, aims at realizing a pre-industrial Accelerator Driven System (ADS) for exploring the transmutation of long lived nuclear waste. The linac for this ADS will be a High Power Proton Accelerator delivering 2.4 MW CW beam at 600 MeV. It has to satisfy stringent requirements for reliability and availability: a beam-MTBF of 250h is targeted. The reliability goal is pursued through a phased approach. During Phase 1, expected till 2024, the MYRRHA linac up to 100 MeV will be constructed. It will allow to evaluate the reliability potential of the 600 MeV linac. It will also feed a Proton Target Facility in which radioisotopes of interest will be collected through an ISOL system. This contribution will focus on the transition to integrated prototyping, which will emphasize (i) a test platform consisting of the initial section of the normal conducting injector (5.9 MeV), (ii) the realization of a complete cryomodule for the superconducting linac and of its cryogenic valve box. The cryomodule will house two 352 MHz single spoke cavities operated at 2K.
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TUPAF014	Beam Dynamics Studies For the IFMIF-DONES SRF-Linac	SRF, cryomodule, cavity, solenoid	687
	L. Du, N. Bazin, N. Chauvin, S. Chel, J. Plouin CEA/IRFU, Gif-sur-Yvette, France
	The DONES (DEMO oriented neutron source) project is aimed at constructing a DEMO of IFMIF to provide sufficient material damage [1]. In the SRF-Linac of this project, losses can cause harmful material activation and must be maintained much less than 1W/m. It's a challenge to keep losses at such a low level with high beam power and high space charge. This paper presents two designs of the DONES SRF-Linac, one with 4 cryomodules and another with 5 cryomodules. The design details to reduce the losses and the multi-particle simulation results will be shown. The errors studies for these results will also be discussed.
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TUPAF017	Stability Analysis of the TOP-IMPLART 35 MeV Proton Beam	DTL, proton, klystron, booster	697
	P. Nenzi, A. Ampollini, G. Bazzano, L. Picardi, C. Ronsivalle, V. Surrenti, E. Trinca, M. Vadrucci ENEA C.R. Frascati, Frascati (Roma), Italy
	Funding: The TOP-IMPLART program is funded by Regione Lazio. The TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTherapy) is the demonstrator of a 150 MeV proton linear accelerator devoted to cancer treatment application under development at ENEA-Frascati. It is a full linear machine composed by a 425 MHz 7 MeV injector and a high frequency linac operating at 2997.92 MHz. The first accelerating section, installed and in operation, consists of 4 SCDTL structures and delivers a 35 MeV beam in 3 microseconds pulses at a maximum repetition frequency of 50 Hz. The principal advantage of a linear accelerator, in a therapeutic application, is the quick setting possibility (up to pulse-to-pulse, in principle) of the physical properties of the proton beam, offering larger flexibility (compared to traditional circular designs) and improved precision on dose delivery to the patient., The short and long range stability of the machine have been analyzed measuring on a pulse by pulse basis both the output beam characteristics and other machine parameters in order to identify those that mainly affect the beam stability. This work describes the methodology used in this study, the main results achieved and the future developments.
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TUPAF018	Characterization of Automatic Frequency Control systems for S-band Proton LINAC "TOP-IMPLART"	DTL, controls, proton, detector	701
	G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle, M. Vadrucci ENEA C.R. Frascati, Frascati (Roma), Italy
	The TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTherapy) proton linear accelerator is under development at ENEA-Frascati. It is composed by a 7 MeV, 425 MHz injector followed by a sequence of 2997.92 MHz accelerating modules. Four 10 MW klystrons will be used to power all high frequency structures up to a beam energy of 150 MeV. The first section, consisting of 4 SCDTL modules (7 to 35 MeV), is operational at low repetition rate (up to 50 Hz). Whereas beam acceleration is effective even without closed loop control, to ensure high beam current stability the resonance frequency variation must be kept for each SDCTL module within few kHz. This is achieved implementing an automatic frequency control (AFC) loop that detects structure detuning caused by thermal drifts and produce an error signal fed to a tuning motor. A prototype of an AFC custom solution, derived from a medical electron linac, has been tested on TOP-IMPLART accelerator. This was originally designed for magnetron frequency tuning with much larger frequency span. Other AFC systems with different components have been evaluated in order to reach the high required resolution.
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TUPAF020	Performance of the CERN Low Energy Ion Ring (LEIR) with Xenon beams	injection, MMI, controls, extraction	705
	R. Alemany-Fernández, S.C.P. Albright, O. Andujar, M.E. Angoletta, J. Axensalva, H. Bartosik, G. Baud, N. Biancacci, M. Bozzolan, S. Cettour Cave, K. Cornelis, J. Dalla-Costa, M. Delrieux, A. Dworak, A. Findlay, F. Follin, A. Frassier, M. Gabriel, A. Guerrero, M. Haase, S. Hirlaender, S. Jensen, V. Kain, L.V. Kolbeck, Y. Le Borgne, D. Manglunki, O. Marqversen, S. Massot, D. Moreno Garcia, D.J.P. Nicosia, S. Pasinelli, L. Pereira, D. Perez, A. Rey, J.P. Ridewood, F. Roncarolo, A. Saá Hernández, R. Scrivens, O.G. Sveen, G. Tranquille, E. Veyrunes CERN, Geneva, Switzerland
	In 2017 the CERN Low Energy Ion Ring demonstrated once more the feasibility of injecting, accumulating, cooling and accelerating a new nuclei, 129Xe39 . The operation of this new ion species started at the beginning of March with the start up of the xenon ion source and the Linac3. Ten weeks later the beam arrived to the Low Energy Ion Ring (LEIR) triggering the start of several weeks of beam commissioning in view of providing the injector complex with Xenon beams for different experiments and a series of machine development experiments in LEIR. Two types of beams were setup, the so called EARLY beam, with a single injection into LEIR from Linac3, and the NOMINAL beam with up to seven injections. 2017 was as well an interesting year for LEIR because several improvements in the control system of the accelerator and in the beam instrumentation were done in view of increasing the machine reliability. This paper summarises the beam commissioning phase and all the improvements carried out during 2017.
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TUPAF034	LEIR Injection Efficiency Studies as a Function of the Beam Energy Distribution from Linac3	injection, cavity, bunching, optics	758
	S. Hirlaender, R. Alemany-Fernández, H. Bartosik, G. Bellodi, N. Biancacci, V. Kain, R. Scrivens CERN, Geneva, Switzerland
	High intensities in the CERN Low Energy Ion Ring (LEIR) are achieved using multi-turn injections from the pre-accelerator Linac3 combined with simultaneous stacking in momentum and transverse phase spaces. Up to seven consecutive 200 μs long, 200 ms spaced pulses are injected from Linac3 into LEIR by stacking each of them into the six-dimensional phase-space over 70 turns. An inclined septum magnet allows proper filling of the transverse phase-space plane, while longitudinal stacking requires momentum variation achieved by a shift of mean momentum over time provided by phase shifting a combination of 2 RF cavities at the exit of Linac3. The achievable maximum accumulated intensity depends strongly on the longitudinal beam quality of the injected beam. The longitudinal Schottky signal is used to measure the received energy distribution of the circulating beam which is then correlated with the obtained injection efficiency. This paper presents the experimental studies to understand and further improve the injection reliability and the longitudinal stacking.
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TUPAF036	Studies of the Injection and Cooling Efficiency in LEIR Using the Longitudinal Schottky Spectrum	injection, diagnostics, electron, pick-up	765
	S. Hirlaender, R. Alemany-Fernández, H. Bartosik, N. Biancacci, V. Kain CERN, Geneva, Switzerland
	The CERN Low Energy Ion Ring (LEIR) has two main operational beams with their associated cycles, the so-called EARLY and the NOMINAL beam. The EARLY beam consists of a single injected pulse from the LINAC3 accelerator, whereas seven consecutive injections are accumulated, and electron cooled for the NOMINAL beam. In both cases, the longitudinal Schottky monitor allows assessing the longitudinal particle distribution during the cooling process on the injection plateau. A method has been established to analyze the Schottky signal, reconstruct the initial particle momentum distribution and derive relevant parameters such as the cooling time, energy off-set of injected and stacked beam or the momentum distribution of the lost beam. The variations of the obtained parameters and the impact on the LEIR performance will be addressed.
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TUPAF042	Characterization of the Beam Energy Spread at the REX/HIE-ISOLDE Linac	cavity, ISOL, experiment, detector	787
	M.L. Lozano, N. Bidault, E. Fadakis, M.A. Fraser, E. Matli, J.A. Rodriguez CERN, Geneva, Switzerland
	ISOLDE is an on-line radioactive isotope separator located at CERN that works by colliding protons accelerated in the PS Booster into a fixed target and by separating the resultant ionized isotopes using a magnetic separator. The completion of the HIE-ISOLDE superconducting linac allows the acceleration of these ions to energy levels that were not reachable before, opening the door to new experiments in different fields. These experiments often have special requirements in terms of beam intensity and purity, transverse emittance or energy spread. A possible way to reduce the energy spread of the beam delivered to the experimental stations is to use one or more of the superconducting cavities as bunchers. The main results of several tests conducted during the last beam commissioning campaign prove that this mode of operation is feasible and will be presented in this paper.
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TUPAF044	Schedule Evolution of the Linac4 Installation During the Lifetime of the Linac4 Project and Connection Forecast	civil-engineering, MMI, status, site	794
	J. Coupard, A. Berjillos, J.-P. Corso, K. Foraz, B. Nicquevert, E. Paulat, M. Vretenar CERN, Geneva, Switzerland
	The new CERN linear accelerator Linac4 started the installation phase in 2010 after the delivery of the new building and tunnel by the civil engineering and was inaugurated six years later. It will be connected to the CERN accelerators chain and replace the current proton linear accelerator, Linac2, during the second long shut-down (LS2) of the Large Hadron Collider (LHC) in 2019. This paper aims to summarize the schedule evolution through the different phases of installation, from general services to machine installation, highlight the key factors that contributed to drive the schedule (safety, logistics and integration) and describe the coordination study of the future connection (integration, schedule, logistics, constraints and priorities).
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TUPAF062	Parametric Study of the Beam Footprint Characteristics on the ESS Target	target, HOM, ion-source, operation	866
	R. Miyamoto ESS, Lund, Sweden H.D. Thomsen ISA, Aarhus, Denmark
	The beam delivery system of the ESS linac utilizes fast oscillating triangular wave dipole magnets of two transverse planes (raster magnets) to spray each long beam pulse (2.86 ms) over a rectangular cross-check pattern on the target. The characteristics of this beam footprint on the target are determined by the amplitudes of the raster magnets, RMS sizes of the beam and, in some case, the tail of the beam profile and have to satisfy the requirements from the target for the peak density as well as the fraction outside of a given rectangular boundary. This paper presents approximate closed-form expressions for the characteristics of the beam footprint and, based on the presented expressions, explores the parameter space of the raster magnets and beam parameters for achieving the optimal characteristics of the beam footprint.
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TUPAF063	Beam Dynamics Studies of the ESS LINAC Using a New Multicell Cavity Model	cavity, emittance, DTL, distributed	870
	R. De Prisco, D.C. Plostinar ESS, Lund, Sweden
	The European Spallation Source is designed to deliver 5 MW proton beam power on the target while keeping the beam induced losses below 1 W/m throughout the LINAC. This implies the need of accurate models to correctly describe the longitudinal beam dynamics within the multi-cell cavities. In all the previous error studies the cells of a multi-cell cavity were modelled as a sequence of independent gaps and the errors were applied directly on the amplitude of each cell accelerating field, considered as random variable. In this paper, instead, we present a new detailed analysis of the effect of the error tolerances on the beam dynamics including a new model to calculate the amplitude errors of the accelerating field in the multi-cell cavities: errors are applied on the geometrical parameters of each cavity; then the accelerating field is calculated solving the Maxwell equations over all the cavity.
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TUPAF064	Preparation Towards the Ess Linac Ion Source and Lebt Beam Commissioning on Ess Site	MMI, rfq, solenoid, site	874
	R. Miyamoto, M. Eshraqi, A. Jansson, E. Laface, Y. Levinsen, O. Midttun, N. Milas, M. Muñoz, D.C. Plostinar, A. Ponton, E. Sargsyan, L. Tchelidze ESS, Lund, Sweden L. Celona, L. Neri INFN/LNS, Catania, Italy W. Ledda Vitrociset s.p.a, Roma, Italy
	Beam commissioning of the proton linac of the European Spallation Source begin in summer, 2018, from the ion source (IS) and low energy beam transport (LEBT), and continues in stages until 2022, when the first beam is sent to its spallation target. This paper presents the plan, status, and highlights of preparation works for the upcoming IS and LEBT beam commissioning.
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TUPAF065	Opportunities and Challenges in Planning the Installation, Testing and Commissioning of Large Accelerator Facilities	MMI, DTL, target, neutron	878
	D.C. Plostinar, D. Bergenholtz, H. Danared, L. Gunnarsson, M.I. Israelsson, A. Jansson, M. Lindroos, A. Sunesson, L. Tchelidze, J.G. Weisend ESS, Lund, Sweden
	Delivering major accelerator facilities requires complex project preparation, organisation and scheduling. Often, multiple factors have to be taken into account including technical, financial and political. This makes planning particularly difficult, but at the same time opens opportunities for improving and optimising the project prospects. In this paper, we discuss the major drivers governing the installation, testing and commissioning of major accelerators in general, with particular emphasis on the European Spallation Source (ESS) accelerator, currently under construction in Lund, Sweden.
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TUPAF074	Preliminary Modelling of Radiation Levels at the Fermilab PIP-II Linac	proton, GUI, booster, radiation	898
	L. Lari, C.M. Baffes, S.J. Dixon, N.V. Mokhov, I.L. Rakhno, I.S. Tropin Fermilab, Batavia, Illinois, USA F. Cerutti, L.S. Esposito, L. Lari CERN, Geneva, Switzerland
	PIP-II is the Fermilab's flagship project for providing powerful, high-intensity proton beams to the laboratory's experiments. The heart of PIP-II is an 800-MeV superconducting linac accelerator. It will be located in a new tunnel with new service buildings and connected to the present Booster through a new transfer line. To support the design of civil engineering and mechanical integration, this paper provides preliminary estimation of radiation level in the gallery at an operational beam loss limit of 0.1 W/m, by means of Monte Carlo calculations with FLUKA and MARS15 codes.
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TUPAF076	Design of PIP-II Medium Energy Beam Transport	vacuum, SRF, kicker, cryomodule	905
	A. Saini, C.M. Baffes, A.Z. Chen, V.A. Lebedev, L.R. Prost, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The Proton Improvement Plan-II (PIP-II) is a proposed upgrade for the accelerator complex at Fermilab. The central piece of PIP-II is a superconducting radio frequency (SRF) 800 MeV linac capable of operating in both CW and pulse regimes. The PIP-II linac comprises a warm front-end that includes a H⁻ ion source capable of delivering 15-mA, 30-keV DC or pulsed beam, a Low Energy Beam Transport (LEBT), a 162.5 MHz, CW Radio-Frequency Quadrupole (RFQ) accelerating the ions to 2.1 MeV and, a 14-m Medium Energy Beam Transport (MEBT) before beam is injected into SRF part of the linac. This paper presents the PIP-II MEBT design and, discusses operational features and considerations that lead to existing optics design such as bunch by bunch chopping system, minimization of radiation coming to the warm front-end from the SRF linac using a concrete wall, a robust vacuum protection system etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF076
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TUPAF085	Status of Link Existing Facility Project for FAIR	shielding, operation, radiation, synchrotron	934
	J. Stadlmann, C. Omet, A. Schuhmann, P.J. Spiller GSI, Darmstadt, Germany
	The project "Link existing Facility", or GaF (GSI Anbindung an FAIR), is an important subproject of the overall FAIR facility. In order to serve as injector for SIS100, the main accelerator of FAIR, the existing GSI synchrotron SIS18 is undergoing an upgrade program leading to about 100 times higher beam intensities. Especially the foreseen operation with 4 GeV Protons with up to 5·10¹² protons per second increases the radiation protection requirements to such an extent that the existing radiation protection measures are no longer sufficient. The project consists of 78 individual measures. The four most substantial activities are the construction of a table-like structure to carry additional shielding. The creation of an opening and a first part of transfer tunnel for the beamlines towards the future FAIR campus. The preparation for the building, beam dump and connection of the FAIR proton injector. The incorporation of state-of-the-art radiation- and fire-protection measures into the present facilities including the a new technical building to house technical infrastructure. We report on the project status which is foreseen to finish mid-2018.
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TUPAF086	Adaption of the HSI -RFQ Rf-Properties to an Improved Beam Dynamics Layout	simulation, rfq, operation, resonance	938
	M. Vossberg, L. Groening, S. Mickat, H. Vormann, C. Xiao GSI, Darmstadt, Germany V. Bencini, J.M. Garland, J.-B. Lallement, A.M. Lombardi CERN, Geneva, Switzerland
	The GSI accelerator facility comprising the linear accelerator UNILAC and the synchrotron SIS18 will be used in future mainly as the injector for the Facility for Anti-Proton and Ion Research (FAIR) being under construction. FAIR requires high beam brilliance and the UNILAC's RFQ electrodes must be upgraded with respect to their beam dynamics design. The new layout is currently being conducted at CERN with the aim of adjusting the electrode voltage according to the design voltage of 123 kV. CST simulations performed at GSI assure that the resonance frequency with the new electrode geometry is recuperated through corrections of the carrier rings. Simulations on the frequency dependence of the rings shapes and their impact on the voltage distribution along the RFQ are presented.
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TUPAF088	Final factory-side Measurements of the Next SC CH-Cavities for the HELIAC-Project	cavity, resonance, heavy-ion, factory	943
	M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, F.D. Dziuba, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany
	Funding: Work supported by the EU Framework Programme H2020 662186 (MYRTE); Work supported by BMBF Contr. No. 05P15RFBA; The upcoming FAIR project (Facility for Antiproton and Ion Research) at GSI will use the existing UNILAC (UNIversal Linear Accelerator) as an injector to provide high intensity heavy ion beams at low repetition rates. As a consequence a new superconducting (sc) continous wave (cw) high intensity heavy ion Linac is required to provide ion beams above the coulomb barrier to keep the Super Heavy Element (SHE) physics program at GSI competitive on an international level. The fundamental Linac design comprises a high performance ion source, the High Charge State Injector (HLI) upgraded for cw-operation and a matching line (1.4 MeV/u) followed by a sc Drift Tube Linac (DTL). Four cryo modules each equipped with three Crossbar-H-mode (CH) structures provide for acceleration up to 7.3 MeV/u. The first section of this ambitious accelerator project has been successfully commissioned and tested with heavy ion beam from the HLI in 2017. It comprises two sc 9.3 T solenoids and a sc 217 MHz CH-cavity with 15 equidistant gaps as a demonstrator. The construction of the next two sc 217 MHz 8 gap CH-cavities is nearly finished and final factory-side measurements will be presented.
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TUPAF089	Initial Measurements on a New 10⁸ MHz 4-Rod CW RFQ Prototype for the HLI at GSI	rfq, simulation, dipole, resonance	946
	D. Koser, K. Kümpel, H. Podlech IAP, Frankfurt am Main, Germany P. Gerhard GSI, Darmstadt, Germany O.K. Kester TRIUMF, Vancouver, Canada
	Funding: Work supported by BMBF Contr. No. 05P15RFBA and HIC for FAIR The High Charge State Injector (HLI) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, is one of the two injector linacs for the Universal Linear Accelerator (UNILAC) and is also planned to serve as dedicated injector for a proposed superconducting CW linac for heavy element research. Within the scope of an intended CW upgrade of the HLI front end, a replacement for the existing 4-rod RFQ is desirable since its stable operation and performance is severely impeded by mechanical vibrations of the electrodes and a high thermal sensitivity. With the aim of suppressing mechanical vibrations and providing efficient cooling considering high power CW operation, a completely new and improved 4-rod design was developed* with a focus on structural mechanical simulations using ANSYS. In order to validate the simulated RF performance, thermal behavior and structural mechanical characteristics, a 6-stem prototype was manufactured**. Initial low power RF measurements and basic piezo actuated mechanical investigations were done and the anticipated properties could be confirmed prior to planned high power RF tests and further mechanical vibration studies. D. Koser et al., THPIK021, Proc. of IPAC2017 D. Koser et al., MOPOY020, Proc. of IPAC2016 * D. Koser et al., TUPLR057, Proc. of LINAC2016
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TUPAK001	Progress of the Modulated 325 MHz Ladder RFQ	rfq, proton, quadrupole, operation	952
	M. Schuett, U. Ratzinger, M. Syha IAP, Frankfurt am Main, Germany
	Funding: BMBF 05P15RFRBA Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.3 m Ladder-RFQ. The unmodulated Ladder-RFQ features a very constant voltage along the axis. It accepted 3 times the operating power of which is needed in operation. That level corresponds to a Kilpatrick factor of 3.1 with a pulse length of 200 μs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project. This particular high frequency creates difficulties for a 4-ROD type RFQ, which triggered the development of a Ladder RFQ with its high symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. The duty cycle is suitable up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in May 2018. We will show the latest results of manufacturing, beam dynamics simulations for the matching between LEBT and RFQ. Journal of Physics: Conf. Series 874 (2017) 012048 **Proceedings of LINAC2016, East Lansing, TUPLR053
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TUPAK002	Advanced Approach for Beam Matching along the Multi-Cavity SC CW Linac at GSI	cavity, heavy-ion, emittance, proton	955
	S. Yaramyshev, W.A. Barth, M. Heilmann GSI, Darmstadt, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	A multi-stage program for the development of a heavy ion superconducting (sc) continuous wave (cw) linac is in progress at HIM (Mainz, Germany) and GSI (Darmstadt, Germany) under support of IAP (Frankfurt, Germany). In 2017 the first section of the CW-Linac has been successfully commissioned at GSI. Beam acceleration at the CW-Linac is foreseen to be performed by up to twelve multi-gap CH cavities. The linac should provide the beam for physics experiments, smoothly varying the output particle energy from 3.5 to 7.3 MeV/u, simultaneously keeping high beam quality. Due to a wide variation of the input- and output -beam energy for each cavity, a longitudinal beam matching to every cavity is of high importance. An advanced algorithm for an optimization of matched beam parameters under variable rf-voltage and rf-phase of each cavity has been developed. The description of the method and the obtained results are presented in the paper.
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TUPAK003	Beam Dynamics Simulations for the New Superconducting CW Heavy Ion LINAC at GSI	cavity, heavy-ion, cryomodule, solenoid	959
	M. Schwarz, M. Basten, M. Busch, H. Podlech IAP, Frankfurt am Main, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany
	Funding: Work supported by BMBF Contr. No. 05P15RFBA and EU Framework Programme H2020 662186 (MYRTE) For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI/HIM and IAP is currently in progress. It aims for developing a supercon-ducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The LINAC design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with unchanged minimum energy spread. Testing of the first CH-cavity in 2016 demonstrated a promising maximum accelerating gradient of E_a = 9.6 MV/m; the worldwide first beam test with this sc multi-gap CH-cavity in 2017 was a milestone in the R&D work of GSI/HIM and IAP. In the light of experience gained in this research so far, the beam dynamics layout for the entire LINAC has recently been updated and optimized.
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TUPAK004	Superconducting CH-Cavity Heavy Ion Beam Testing at GSI	cavity, heavy-ion, acceleration, emittance	962
	W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany K. Aulenbacher IKP, Mainz, Germany K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	Recently the first section of a standalone superconducting (sc) continuous wave (cw) heavy ion Linac as a demonstration of the capability of 217 MHz multi gap Crossbar H-mode structures (CH) has been commissioned and extensively tested with beam from the GSI- High Charge State Injector. The demonstrator set up reached acceleration of heavy ions up to the design beam energy and beyond. The required acceleration gain was achieved with heavy ion beams even above the design mass to charge ratio at high beam intensity and full beam transmission. This contribution presents systematic beam measurements with varying RF-amplitudes and phases of the CH-cavity, as well as versatile phase space measurements for heavy ion beams with different mass to charge ratio. The worldwide first and successful beam test with a superconducting multi gap CH-cavity is a milestone of the R&D work of Helmholtz Institute Mainz (HIM) and GSI in collaboration with Goethe University Frankfurt (GUF) in preparation of the sc cw heavy ion Linac project and other cw-ion beam applications.
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TUPAK008	Longitudinal Bunch Size Measurements with an RF Deflector at J-PARC LINAC	simulation, radio-frequency, rfq, DTL	974
	M. Otani, K. Futatsukawa KEK, Tsukuba, Japan K. Hirano, A. Miura JAEA/J-PARC, Tokai-mura, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta FRIB, East Lansing, USA
	Measurement of the longitudinal bunch size is important for the stable beam operation. Especially in a medium energy beam transport (MEBT) located after a radio-frequency quadrupole in J-PARC, it is necessary to measure the bunch size with minimum set of equipment to avoid subsequent emittance growth due to space charge. We had proposed a longitudinal size measurement with an rf deflector normally used for deflecting theμbunch; phase spread is migrated to spatial one if the reference particle arrives at the deflector when the voltage is rising in time and is zero. Then a buncher cavity located upstream of the deflector is utilized to scan the phase spread to measure the longitudinal beam parameters. In this poster, recent measurement results are presented.
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TUPAK009	Muon Profile Measurement After Acceleration With a Radio-Frequency Quadrupole Linac	experiment, simulation, rfq, positron	977
	M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, T. Yamazaki KEK, Tsukuba, Japan S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko SNU, Seoul, Republic of Korea K. Hasegawa, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan T. Iijima, Y. Sue Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H. Iinuma, Y. Nakazawa Ibaraki University, Ibaraki, Japan K. Ishida RIKEN Nishina Center, Wako, Japan R. Kitamura University of Tokyo, Tokyo, Japan S. Li The University of Tokyo, Graduate School of Science, Tokyo, Japan G.P. Razuvaev Budker INP & NSU, Novosibirsk, Russia N. Saito J-PARC, KEK & JAEA, Ibaraki-ken, Japan E. Won Korea University, Seoul, Republic of Korea
	Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784. The E34 experiment aims to measure muon anomalous magnetic moment with a precision of 0.1ppm. The experiment utilizes low emittance muon beam with a muon linac to sweep out beam related uncertainties, which limit the g-2 precision in past experiments. A beam matching with precise beam measurements is required to avoid substantial emittance growth and satisfy the experimental requirement on the beam emittance of around 1.5 pi mm mrad. We conduct profile measurement of muon after acceleration with a radio-frequency quadrupole (RFQ) on December 2017 following a first muon acceleration experiment on October. In the experiment of profile measurement, epi-thermal negative muonium ions are generated by injecting surface muons to a thin metal foil. The muonium ions are accelerated to 5 keV. by an electro-static lens and accelerated to 90 keV by the RFQ. Then the muonium ions are transported to a profile detector consisting of a micro-channel plate and a ccd camera via a quadrupole pair and a bending magnet. In this poster, the experimental result and comparison to the simulation are reported.
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TUPAK015	The SARAF-LINAC Project 2018 Status	cryomodule, cavity, status, controls	994
	N. Pichoff, D. Chirpaz-Cerbat, R. Cubizolles, J. Dumas, R.D. Duperrier, G. Ferrand, B. Gastineau, P. Gastinel, F. Gougnaud, M. Jacquemet, C. Madec, Th. Plaisant, F. Senée, A. Sutra-Fourcade, D. Uriot IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France D. Berkovits, J. Luner, A. Perry, E. Reinfeld, J. Rodnizki Soreq NRC, Yavne, Israel M. Di Giacomo GANIL, Caen, France
	SNRC and CEA collaborate to the upgrade of the SARAF accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). CEA is in charge of the design, construction and commissioning of the MEBT line and the superconducting linac (SARAF-LINAC Project). The prototypes of the 176 MHz NC rebuncher, SC cavities, RF coupler and SC Solenoid-Package are under construction and their test stands construction or adaptation is in progress at Saclay. Meanwhile, the cryomodules and the global system just passed their Critical Design Reviews. This paper presents the status of the SARAF-LINAC Project at April 2018.
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TUPAL003	Measurement of the Injection Beam Parameters by the Multi-Wire Scanner for CSNS	injection, proton, MMI, neutron	1014
	M.Y. Huang, H.C. Liu, S. Wang, Zh.H. Xu, P. Zhu IHEP, Beijing, People's Republic of China X.H. Lu CSNS, Guangdong Province, People's Republic of China
	In order to inject the H⁻ beam to the Rapid Cycling Synchrotron (RCS) with high precision and high transport efficiency, the injection beam parameters need to be measured and then corrected while its eccentric position or direction angle is too large. In this paper, firstly, a method to measure the injection beam parameters by using two of the four multi-wire scanners (MWSs) is presented. The injection commissioning results confirmed that this method works well. Secondly, a method to measure the signals of injection beam and circular beam by the INMWS02 is presented and the method work well during the beam commissioning.
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TUPAL012	Design and Fabrication of Hybrid RFQ Prototype	DTL, rfq, cavity, site	1032
	P.Y. Yu, Y. He, C.X. Li, G.Z. Sun, F.F. Wang, Z.J. Wang, B. Zhang, T.M. Zhu IMP/CAS, Lanzhou, People's Republic of China
	Hybrid RFQ is proposed as a potential good choice at the low-energy range of linear accelerator. The complexi-ty of mechanical design and difficulty of fabrication are part of reasons impeding application of it and similar structures. In order to explore the practicable structure and research on RF parameters of this accelerating struc-ture, an aluminium prototype is developed.
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TUPAL017	Performance and Status of the J-PARC Accelerators	operation, target, ion-source, status	1038
	K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki JAEA/J-PARC, Tokai-mura, Japan T. Koseki, F. Naito, M. Yoshii KEK, Tokai, Ibaraki, Japan N. Yamamoto J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). Regarding 3 GeV beam from the RCS, we delivered it at 150 kW to the materials and life science experimental facility (MLF), for the neutron and muon users. The beam powers for the neutrino experiment at 30 GeV was 420 kW in May 2016, but increased to 470 kW in February 2017 thanks to the change and optimization of operation parameters. For the hadron experimental facility which uses a slow beam extraction mode at 30 GeV, we delivered beam at a power of 37 kW, after the recovery from a trouble at an electro static septum. We have experienced many failures and troubles to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.
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TUPAL022	Low-Reflection RF Window for ACS Cavity in J-PARC Linac	cavity, Windows, proton, impedance	1051
	J. Tamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan H. Ao FRIB, East Lansing, USA F. Naito, M. Otani KEK, Tokai, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In the Japan Proton Accelerator Research Complex (J-PARC) linac, the Annular-ring Coupled Structure (ACS) cavities have been stably operating. To maintain this operation availability, we manufactured three backups of the pillbox-type RF windows for the ACS cavities in fiscal year 2015 and 2017. It is desirable to minimize the RF reflection of the RF window to prevent standing waves from exciting between the cavity and the RF window, and not to significantly change the optimized coupling factor between the cavity and the waveguide. To realize the minimization, the relative permittivities of the ceramic disks of the RF windows were evaluated by measuring the resonant frequencies of the pillbox cavity containing the ceramic disk. On the basis of the evaluated relative permittivities, the pillbox-part lengths of the RF windows were determined. The measured Voltage Standing Wave Ratios (VSWRs) of the manufactured RF windows are just about 1.08 and these are applicable for the practical use.
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TUPAL031	Errors Study of a Double-Pass Recirculating Superconducting Proton Linac	proton, cavity, emittance, quadrupole	1069
	Y. Tao, K. Hwang, J. Qiang LBNL, Berkeley, California, USA
	The concept of recirculating superconducting proton linac was recently proposed. Beam dynamics simulations were carried out in a double-pass recirculating proton linac using a single bunch. Although all the beam line elements should be installed following the designed values, in reality, there exist machine imperfections that will cause beam off-centering and even particle losses. In this paper, we report on the study of the static and dynamic errors from RF cavities and magnetic focusing elements in the double-pass recirculating proton linac.
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TUPAL032	A Variable Field Phase-Shifter for Recirculating Proton Linacs	cavity, dipole, proton, superconducting-cavity	1072
	Y. Tao, J. Qiang LBNL, Berkeley, California, USA
	The recirculating superconducting proton linac that has a potential to substantially save accelerator cost was re-cently proposed. It consists of three sections to accelerate the continues-wave (CW) beam to multiple GeVs. In the first section, the beam passes the linac two times. In the second and third sections, the beam goes through the linac four and six times. A phase-shifter is needed to meet the synchronous acceleration condition for multi-pass accel-eration using the same RF cavity due to the phase slip-page of the proton beam. Here we present the design of a variable field rectangular bend phase-shifter in which the beam goes to a different path in each pass inside the mag-net to meet the synchronous condition.
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TUPAL033	Time-of-Flight, Beam-Energy Measurement of the LANSCE 805-MHz Linac	proton, pick-up, controls, DTL	1075
	Y.K. Batygin, F.E. Shelley, H.A. Watkins LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396. Control of the beam-energy ramp along the length of a proton linear accelerator is required to keep the accelerator tuned according to design. Historically, the values of the field amplitudes and phases of the side-coupled, 805-MHz LANSCE linac modules are maintained using a well-known delta-t tuning procedure. Time-of-flight measurements of the proton beam energy are now also being used to confirm and improve the overall control of the energy ramp along the linac. The time-of-flight method uses measurements of the difference in RF phases measured as the beam passes installed delta-t pickup loops. A newly developed chassis to control the 3D position of the beam centroid is used. Details of the procedure and results of measurements are presented. K.R.Crandall, "The Delta-T Tuneup Procedure for the LAMPF 805-MHz Linac", LANL Report LA-6374-MS, June 1976.
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TUPAL034	Effect of 805-MHz Linac RF Stability on Beam Losses in LANSCE High-Energy Beamlines	beam-losses, neutron, proton, operation	1078
	Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396. Operation of an accelerator facility critically depends on stability of the field amplitudes and phases of the accelerating cavities. The LANSCE linear accelerator consists of a 201.25-MHz, drift-tube linac and an 805-MHz, side-coupled-cavity linac (SCL). Beam losses in the high-energy beamlines of the 800-MeV facility were measured versus variation of the amplitudes and phases of the 805-MHz, SCL, RF cavities. A recent study* confirms that to achieve low losses, the stability of the amplitudes and phases should be kept within 0.1% and 0.1o, respectively. This agrees with a previous study of beam losses in the 201.25-MHz linac. Details of the measurements and results are presented. *L.J.Rybarcyk, R.C.McCrady, Proceeding of LINAC2016, East Lansing, MI, USA, MOPLR072, p.301.
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TUPAL037	Installation Progress on FRIB β=0.041 Cryomodules Toward Beam Commissioning	MMI, cryomodule, diagnostics, cryogenics	1087
	H. Ao, B. Bird, N.K. Bultman, F. Casagrande, C. Compton, K.D. Davidson, K. Elliott, V. Ganni, A. Ganshyn, P.E. Gibson, I. Grender, W. Hartung, L. Hodges, K. Holland, A. Hussain, M. Ikegami, S. Jones, P. Knudsen, S.M. Lidia, I.M. Malloch, E.S. Metzgar, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, T. Russo, K. Saito, M. Shuptar, S. Stanley, S. Stark, D.R. Victory, J. Wei, J.D. Wenstrom, M. Xu, T. Xu, Y. Xu, Y. Yamazaki, Q. Zhao, S. Zhao FRIB, East Lansing, USA A. Facco INFN/LNL, Legnaro (PD), Italy R.E. Laxdal TRIUMF, Vancouver, Canada M. Wiseman JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams (FRIB) driver linac is to accelerate all the stable ion beams from proton to uranium beyond 200 MeV/u with beam powers up to 400 kW, which will be the first large-scale, CW SRF ion linac. The beam commissioning of the front end (from the ion source to the RFQ) already began and is in progress. The Accelerator Readiness Review (ARR) for beam through the first three β=0.041 cryomodules is scheduled for May 2018. The next step is the beam commissioning through the 12 SRF cavities housed in these 3 cryomodules with 6 superconducting solenoid magnets. The cryomodules and the adjacent warm diagnostics boxes in between have been already installed and aligned in the tunnel. This paper describes the installation progress of the β=0.041 cryomodules and plans for ARR02.
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TUPAL046	Construction, Test, and Operation of a new RFQ at the Spallation Neutron Source (SNS)	rfq, operation, ion-source, vacuum	1113
	Y.W. Kang, A.V. Aleksandrov, W.E. Barnett, M.S. Champion, M.T. Crofford, B. Han, S.W. Lee, J. Moss, R.T. Roseberry, J.P. Schubert, A.P. Shishlo, M.P. Stockli, C.M. Stone, R.F. Welton, D.C. Williams, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA C.C. Peters, J. Price ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: * This work was supported by SNS through UT-Battelle, LLC, under contract DEAC0500OR22725 for the U.S. DOE. A new RFQ was successfully installed recently in the SNS linac to replace the old RFQ that was used for more than a decade with certain operational limitations. The new RFQ was completely tested with H⁻ ion source in the Beam Test Facility (BTF) at SNS. For robust operation of SNS at 1.4 MW, the full design beam power and to satisfy the beam current requirement of the forthcoming SNS proton power upgrade (PPU) project, an RFQ with enhanced performance and reliability was needed. The new RFQ was built to have the beam parameters identical to those of the first RFQ but with improved RF and mechanical stability and reliability for continuous operation of neutron production. The tests confirmed that the new RFQ can run with high beam transmission efficiency at around 90 % and notably improved operational stability. In this paper, construction, test, installation, and operation of the new RFQ in SNS are discussed with the performance improvements.
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TUPAL049	SNS Proton Power Upgrade Status	scattering, proton, cavity, injection	1120
	M.A. Plum, G. A. Bloom, M.S. Champion, J. Galambos, M.P. Howell, S.-H. Kim, J. Moss, B.W. Riemer, K.S. White ORNL, Oak Ridge, Tennessee, USA R.B. Saethre, R. W. Steffey ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. This research was supported by the DOE Office of Science, Basic Energy Science, Scientific User Facilities. The Spallation Neutron Source (SNS) Proton Power Upgrade (PPU) project aims to double the proton accelerator beam power from 1.4 to 2.8 MW. Over the past year PPU has completed the reviews necessary for Critical Decision-1 approval. The baseline design choices are being refined, and a cost-effective approach has been identified. The beam energy will be increased by 30% and the beam current capability improved by ~50%. The sub-system improvements and anticipated schedule will be discussed.
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TUPAL051	Program for High-Intensity RFQ Design With Matched and Equipartitioned Design Strategy	rfq, emittance, ISOL, resonance	1126
	H.P. Li, M.J. Easton, Q. Fu, P.P. Gan, Y.R. Lu, Q.Y. Tan, Z. Wang, K. Zhu PKU, Beijing, People's Republic of China
	The deuteron driver accelerator of the Beijing Iso-tope Separation On-Line (BISOL) facility will acceler-ate and deliver a 20 mA deuteron beam to the targets with an energy of 40 MeV. As the injector of the driver linac, an RFQ is required to bunch and accelerate the 20 mA deuteron beam to 3 MeV with very high beam quality. In order to fulfil these requirements and re-duce time spent on optimization, an RFQ design pro-gram named RFQEP has been developed to generate the input file for the PARMTEQM code. In this program, the ‘matched and equipartitioned' design strategy is adopted to prevent halo formation and to avoid struc-ture resonances in high intensity RFQs. The detailed design aspects are studied in this paper and simulation results are given for an RFQ designed by this code, which shows the accuracy and the merits of the new program.
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TUPAL052	Multi-Physics Analysis of a CW IH-DTL for CIFNEF	DTL, cavity, neutron, operation	1129
	Q.Y. Tan, M.J. Easton, Q. Fu, P.P. Gan, H.P. Li, Y.R. Lu, Z. Wang PKU, Beijing, People's Republic of China
	The Compact Intense Fast NEutron Facility (CIFNEF) project aims to produce high intense neutrons via the 7Li (d, n) 8Be reaction using a 5 MeV, 10 mA deuteron linac. The main components of the linac are an ion source, a short radio frequency quadrupole (RFQ) and an interdigi-tal H-mode drift tube linac (IH-DTL). The IH-DTL will accelerate the continuous wave (CW) deuteron beam from 1 MeV to 5 MeV with a total cavity length of 1.25 m using Kombinierte Null Grad Struktur (KONUS) design, achieving an accelerating gradient of 3.2 MV/m. The RF power loss for the whole cavity is estimated to be 85 kW. This high power loss is a significant challenge to the cooling design, as it could cause large rises in tempera-ture, thermal deformation and frequency drift. A detailed multi-physics analysis of the CW IH-DTL is presented in this paper.
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TUPAL073	Conceptual Design of a Drift Tube LINAC for Proton Therapy	DTL, emittance, proton, rfq	1182
	P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng TUB, Beijing, People's Republic of China Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People's Republic of China
	Funding: National Key Research and Development Program of China (grant number 2016YFC0105408) The conceptual design of an Alvarez-type Drift Tube Linac for one proton therapy facility is described in this paper. The design optimization of the Drift Tube Linac is carried out in the principle of adopting domestic mature technologies and cost control. The error study of the Drift Tube Linac is also given in this paper.
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TUPAL075	Mechanical Design and Error Analysis of a 325 MHz IH-DTL Test Cavity	DTL, alignment, cavity, simulation	1186
	R. Tang, C.T. Du, X. Guan, K.D. Man, C.-X. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People's Republic of China J. Li NUCTECH, Beijing, People's Republic of China
	A 325 MHz interdigital H-mode drift tube linac (IH-DTL) test cavity with a modified KONUS beam dynamics is under fabrication at Tsinghua University. The inner diameter of the tank increases from 196.8 to 232.6 mm. The mechanical design is considered carefully because of its small geometry. A three-piece design has been adopted in the mechanical design. The error analysis is carried out to determine the error requirement of machining and alignment. The details of mechanical design and error analysis is presented.
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TUPAL077	2D-3D PIC Code Benchmarking/Anchoring Comparisons For a Novel RFQ/RFI LINAC Design	rfq, space-charge, simulation, experiment	1194
	S.J. Smith, S. Biedron, A. M. N. Elfrgani, E. Schamiloglu University of New Mexico, Albuquerque, USA M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson Ion Linac Systems, Inc., Albuquerque, USA K. Kaneta CICS, Tokyo, Japan
	Funding: *The study at the University of New Mexico was supported in part by DARPA Grant N66001-16-1-4042 and gift to the University of New Mexico Foundation by ILS. In this study, comparisons are made between several particle dynamics codes (namely CST Particle Studio, GPT, and upgraded PARMILA codes) in order to benchmark them. The structure used for the simulations is a novel 200 MHz, 2.5 MeV, CW RFQ/RFI LINAC designed by Ion Linac Systems (ILS). The structure design and parameters are provided, simulation techniques are explained, and results from all three code families are presented. These results are then compared with each other, identifying similarities and differences. Numerous parameters for comparison are used, including the transmission efficiency, Q-factor, E-field on axis, and beam properties. Preliminary anchoring between modeling and simulation performance predictions and experimental measurements will be provided.
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TUZGBF5	KlyLac Prototyping for Borehole Logging	klystron, cavity, feedback, simulation	1244
	A.V. Smirnov, R.B. Agustsson, M.A. Harrison, A.Y. Murokh, A.Yu. Smirnov RadiaBeam Systems, Santa Monica, California, USA S. Boucher, T.J. Campese, K.J. Hoyt RadiaBeam, Los Angeles, California, USA E.A. Savin MEPhI, Moscow, Russia A.A. Zavadtsev Nano, Moscow, Russia
	Funding: Work supported by the U.S. Department of Energy (award No. DE-SC0015721) Linac-based system for borehole logging exploits KlyLac approach combing klystron and linac sharing the same electron beam, vacuum volume, and RF network enabling self-oscillation due to a positive feedback. The KlyLac prototype design tailors delivering ~1 MeV electrons in a linac section using part of the beam injected from a sheet beam klystron (SBK). The linac part is based on a very robust, high group velocity, cm-wave, and a standing wave accelerating structure of a 'cross-pin' type supplied by a sampler. The SBK part features a permanent magnet solenoid focusing, relatively low voltage, and high aspect ratio beam. The main SBK characteristics (perveance, power, and efficiency) are expected to be similar to that for a magnetron.
	Slides TUZGBF5 [3.280 MB]
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TUPMF024	Validation of the Halbach FFAG Cell of Cornell-BNL Energy Recovery Linac	permanent-magnet, quadrupole, collider, focusing	1304
	F. Méot, S.J. Brooks, 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 optical properties of the Halbach technology based CBETA ERL return FFAG arc cell are investigated, using its 3-D OPERA field map model. This includes paraxial and large amplitude motion, tune path, study of resonances, dynamic acceptance, effects of various defects, 300-cell 10k-particle bunches 6D transmission trials. These investigations, a 2~3 year investment, have validated the Halbach technology in the linear FFAG cell application, from the point of view of the beam dynamics, so supporting its approval as the required technology for CBETA, in December 2016.
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TUPMF036	Top Off of NSLS-II with Inefficient Injector	booster, injection, storage-ring, operation	1327
	R.P. Fliller, A.A. Derbenev, V.V. Smaluk, X. Yang BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The NSLS-II is a 3 GeV storage with a full energy injector capable of top off injection. The injector consists of a 200 MeV linac injecting a 3 GeV booster. Recent operational events have caused us to investigate 100 MeV injection into the booster. As the booster was not designed for injection at this low energy, beam loss is observed with this low energy booster injection. This beam loss not only results of overall charge loss from the train, but a change in the overall charge distribution in the bunch train. In this paper we discuss the performance of injecting into the storage ring with the inefficient charge transfer through the injector. The changes to the top off method are discussed, as well as the achieved storage ring current stability and fill pattern.
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TUPMF037	Development of New Operational Mode for NSLS-II Injector: Low Energy 100MeV Linac-to-Booster Injection	booster, injection, operation, klystron	1330
	X. Yang, A.A. Derbenev, R.P. Fliller, T.V. Shaftan, V.V. Smaluk BNL, Upton, Long Island, New York, USA
	The NSLS-II injector consists of a 200 MeV linac and a 3 GeV full-energy booster synchrotron. The linac contains five traveling-wave S-band accelerating structures driven by two high-power klystrons, with a third klystron as spare. In the event that the spare klystron is not available, the failure of one klystron will prohibit the linac from injecting into the booster as the energy is too low. Therefore, we wish to develop a new operational mode that the NSLS-II injector can operate with a single klystron providing 100 MeV beam from the linac. A decremented approach with intermediate energies 170 MeV, 150 MeV, etc., takes advantages of pre-calculated booster ramps and beam based online optimization. By lowering the booster injection energy in a small step and online optimizing at each step, we were able to achieve 100 MeV booster injection. 170 MeV operation mode of the NSLS-II injector has been implemented since May 31, 2017, with a similar overall performance compared to the standard 200 MeV operation but fewer klystron trips. 100 MeV single-klystron operation has been successfully demonstrated with 20-30% overall efficiency, which is limited by booster acceptance.
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TUPMF058	Conceptual Design of HEPS Injector	booster, storage-ring, injection, dipole	1394
	J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou IHEP, Beijing, People's Republic of China
	Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.
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TUPMF060	Design of Bunch Lengthening System in Electron Linac	booster, photon, lattice, bunching	1401
	C. Meng, Y. Jiao, J.L. Li, S. Pei, Y.M. Peng, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance light source to be built in China. The injector is composed of a linac and a full energy booster. To increase the threshold of TMCI in the booster, the HEPS linac design has been evolved with several iterations. The important middle-version design is a 300 MeV linac with rms bunch length larger than 20 ps. One bunch lengthening system is proposed and discussed in this paper.
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TUPMF061	Physical Design of the 500 MeV Electron Linac for the High Energy Photon Source	electron, gun, bunching, emittance	1404
	S. Pei, D.Y. He, X. He, J.L. Li, J. Liu, X. Ma, C. Meng, X. Wang, O. Xiao, J.R. Zhang, Z.S. Zhou IHEP, Beijing, People's Republic of China S. Shu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	Funding: Work supported by the HEPS project and the National Natural Science Foundation of China (11475201). peisl@ihep.ac.cn The High Energy Photon Source (HEPS) is a 6 GeV light source with ultra-low emittance, it is proposed to be built at Huairou district, northeast suburb of Beijing, China. A 500 MeV electron linac will be used to generate the electron beam for injection into the booster. Here the preliminary physical design of the electron linac is presented.
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TUPMF063	The Considerations of Improving TMCI Threshhold on HEPS Booster	booster, lattice, storage-ring, injection	1411
	Y.M. Peng, J.L. Li, C. Meng, S. Pei, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is proposed in Beijing, China. The on-axis swap-out injection scheme will be used in the storage ring mainly because of the small dynamic aperture. Therefore, the booster needs to store more than 2.5 nC bunch charge. Under this requirement, the transverse mode coupling instability (TMCI) at the injection energy becomes the bunch charge restriction in the booster. Several changes in booster and linac for improving bunch charge threshold limited by TMCI are considered. The details will be expressed in this paper.
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TUPMF081	Microphonic Detuning Induced Coupler Kick Variation at LCLS-II	cavity, laser, free-electron-laser, beam-loading	1456

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MOXGB2

ARIEL at TRIUMF: Science and Technology

TRIUMF, ISAC, target, cyclotron

6

J.A. Bagger, F. Ames, Y. Bylinskii, A. Gottberg, O.K. Kester, S.R. Koscielniak, R.E. Laxdal, M. Marchetto, P. Schaffer
TRIUMF, Vancouver, Canada
M. Hayashi
TRIUMF Innovations Inc., Vancouver, Canada

The Advanced Rare Isotope Laboratory (ARIEL) is TRIUMF's flagship project to create isotopes for science, medicine and business. ARIEL will triple TRIUMF's rare isotope beam capability, enabling more and new experiments in materials science, nuclear physics, nuclear astrophysics, and fundamental symmetries, as well as the development of new isotopes for the life sciences. Beams from ARIEL's new 35 MeV, 100kW electron linear accelerator and from TRIUMF's original 500 MeV cyclotron will enable breakthrough experiments with the laboratory's suite of world-class experiments at the Isotope Separator and Accelerator (ISAC) facility. This invited talk will present an overview of TRIUMF, the ARIEL project, and the exciting science they enable.

Slides MOXGB2 [65.004 MB]

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MOYGB1

Status and Future Strategy for Advanced High Power Microwave Sources for Accelerators

klystron, electron, cavity, operation

12

F. Gerigk
CERN, Geneva, Switzerland

The need for more energy efficient high power microwave devices for accelerator applications continues to increase. This is important for development of cost effective accelerator designs that are coming up in the near future. Efforts are already in place to design new devices that could stretch the limits of RF power conversion to the highest levels possible. Devices including new technologies and design innovations like multi beam, increased number of cavities designs are being considered. Advances in the application of solid state amplifiers to accelerators are also being realized. This invited talk will cover the recent advances and status of such efforts. It will discuss future needs and a strategy for pursuing these efforts on a faster time scale for the benefit of the accelerator community.

Slides MOYGB1 [11.575 MB]

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MOYGB2

The LCLS-II: A High Power Upgrade to the LCLS

cavity, undulator, cryomodule, electron

18

J.N. Galayda
SLAC, Menlo Park, California, USA

Funding: The work is supported by DOE under grant No. DE-AC02-76SF00515
The LCLS-II is an upgrade of the LCLS X-ray FEL based on a 4 GeV superconducting RF linac. The LCLS-II is designed to produce 100's of Watts of X-rays from 200 eV up to 5 keV. The linac uses 1.3 GHz 9-cell cavities processed using the N2-doping technique and will be the first large scale CW SCRF linac with a Q of roughly 3x10¹⁰ at a gradient of 16 MV/m. The injector which will be commissioned in spring 2018, is based on the normal conducting CW RF APEX gun developed at LBNL. The LCLS-II will have two undulators: the soft X-ray undulator is a 39 mm period hybrid PM with an adjustable vertical gap to cover the range from 200 eV to 1.5 keV and hard X-ray undulator is a novel adjustable horizontal gap hybrid PM undulator with 26 mm period to generate vertically polarized X-rays from 1 to 5 keV. The talk will review the performance goals as well as the hardware fabrication.

Slides MOYGB2 [11.367 MB]

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MOZGBD5

A Proposal for Coherent Hard X-Ray Generation Based on Two-Stage EEHG

FEL, electron, laser, radiation

38

Z.T. Zhao, J.H. Chen, C. Feng, Z. Wang, K.Q. Zhang
SINAP, Shanghai, People's Republic of China

A two stage echo-enabled harmonic generation (EEHG) scheme to produce coherent hard X-rays is presented. Electron bunchs of quite different lengths are separately used in each stage of EEHG and a monochromator is employed to purify the radiation from the first stage for seeding the second one. Theoretical analysis and 3D simulations show that the proposed scheme can generate fully coherent hard X-ray pulses directly from a conventional UV seed laser.

Slides MOZGBD5 [7.330 MB]

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MOZGBF4

Evolution of the Superconducting Linac Output Energy at the Spallation Neutron Source

cavity, cryomodule, operation, SRF

73

S.-H. Kim, D.E. Anderson, M.T. Crofford, M. Doleans, J. Galambos, S.W. Gold, M.P. Howell, M.A. Plum, D.J. Vandygriff
ORNL, Oak Ridge, Tennessee, USA
R. Afanador, D.L. Barnhart, B. DeGraff, J.D. Mammosser, C.J. McMahan, T.S. Neustadt, C.C. Peters, J. Saunders, D.M. Vandygriff
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
The SNS linac output energy has increased since the start of neutron production in FY2007. The various improvements that contributed to the increase of the linac output energy are LLRF/control system improvement, high voltage converter modulator system improvement, high-power RF system improvement, cryomodule repairs, spare cryomodule development and accelerating gradient improvement through in-situ plasma processing. In this paper, the history of the SNS SCL output energy is reported, and plans for the near-term future and for the Proton Power Upgrade (PPU) project are also presented.

Slides MOZGBF4 [34.185 MB]

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MOPMF001

Bunch Schedules for the FCC-ee Pre-injector

injection, collider, booster, positron

79

S. Ogur, K. Oide, Y. Papaphilippou, F. Zimmermann
CERN, Geneva, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

The latest design of the Future Circular electron-positron Collider (FCC-ee) foresees a luminosity per interaction point above 2.0·10³⁶/cm²/s for operation at the Z pole. The filling from zero current occurs in collision to profit from the bunch lengthening due to beamstrahlung (so-called bootstrapping). At any time when new e^- and e⁺ buckets or bunchlets are injected into the collider, they will collide instantly. For this reason, we may provide the charge in each injected bunch in a way to pre-compensate for anticipated beam loss, and to reach the target luminosity as soon as possible after the first injection. In this way, we optimise the injection schedules for Z-mode so as to reach the peak luminosity in less than 20 minutes by interleaved injection of the two species at some portion of full bucket charge. Filling from zero the injector should allow accumulating 1.7·10¹¹ particles in one collider bucket within at least 10 injections, assuming a total transmission above 80%. In steady-state operation, the injector chain continually produces and accelerates lower bunch charges so as to maintain nearly constant bunch currents and constant peak luminosity.

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MOPMF005

Beam Formation in the Alternative JLEIC Ion Complex

booster, collider, injection, proton

91

B. Mustapha, J.L. Martinez Marin
ANL, Argonne, USA
Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy / ONP, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The proposed alternative design approach for the JLab-EIC (JLEIC) ion complex uses a more compact linac and pre-booster, and consolidates the electron storage ring (e-ring) as a large booster for the ions. Following a parameter study* showing the feasibility of this alternative design approach, we have adapted the e-ring lattice by adding RF sections to accelerate ion beams**. In this study, we focus on the beam formation for protons and lead ions from the linac to the pre-booster, then into the e-ring until injection to the ion collider ring. Effects such as space charge, intra-beam scattering and the need for beam cooling will determine the total accumulated charge in each ring and the time required from injection from the injector linac to collision in the collider ring.
* B. Mustapha et al, Proceedings of NAPAC-2016, October 9-14, Chicago, IL.
** B. Mustapha et al, Proceedings of IPAC-2017, May 14-19, Copenhagen, Denmark.

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MOPMF034

Layout and Performance of the FCC-ee Pre-Injector Chain

emittance, damping, injection, cavity

169

S. Ogur, T.K. Charles, K. Oide, Y. Papaphilippou, L. Rinolfi, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, P.V. Martyshkin, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
I. Chaikovska, R. Chehab
LAL, Orsay, France
K. Furukawa, N. Iida, T. Kamitani, F. Miyahara
KEK, Ibaraki, Japan
E.V. Ozcan
Bogazici University, Bebek / Istanbul, Turkey
S.M. Polozov
MEPhI, Moscow, Russia

The Future Circular e⁺e⁻ Collider pre-injector chain consists of a 6 GeV S-Band linac, a damping ring at 1.54 GeV and pre-booster ring to reach 20 GeV for injection to the main booster. The electron and positron beams use the same accelerator chain alternatively. The e⁺ beam is generated from a novel low level RF-gun providing 6.5 nC charge at 11 MeV with 0.5 micron geometric emittance. The e⁺ beam is produced by the impact of a 4.46 GeV e^- beam onto a hybrid target, accelerated in the linac up to 1.54 GeV, and injected to the damping ring for emittance cooling. Simulations on the performance of the DR are presented for reaching the required equilibrium emittances at the required damping time. As an alternative option, a 20 GeV linac is considered utilising C-Band cavities and simulations studies have been undertaken regarding the beam transport and transmission efficiency up to that energy.

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MOPMF055

Update of the CLIC Positron Source

positron, target, electron, simulation

236

Y. Han, L. Ma
SDU, Shandong, People's Republic of China
C. Bayar
Ankara University, Faculty of Sciences, Ankara, Turkey
S. Döbert, A. Latina, D. Schulte
CERN, Geneva, Switzerland

The baseline positron source of CLIC has been optimised for the 3 TeV c.o.m. energy. Now the first stage of the CLIC is proposed to be at 380 GeV. Recently, the positron transmission efficiency from the tungsten target to the damping rings injection has been improved by 2.5 times. This opened the possibility for an optimisation of the whole positron source, comprising the injector linacs, aimed at improving its performance and its overall power efficiency. In this paper the key parameters of the positron source, which include the current and the energy of the primary electron beam, the thickness of the crystal and amorphous tungsten targets, the distance between the two targets, the adiabatic matching device (AMD) and pre-injector linacs, are optimized to improve the overall power efficiency.

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MOPMF073

Rejuvenation of 7-Gev SuperKEKB Injector Linac

positron, electron, emittance, injection

300

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimura, T. Suwada, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It was upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of flavor physics beyond the standard model of elementary particle physics. SuperKEKB energy-asymmetric electron-positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. The electron beam is generated by a new type of RF gun, that provides a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 μm to 10 μm in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The summary of the rejuvenation is reported.

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MOPMF074

Beam Phase Space Jitter and Effective Emittance for SuperKEKB Injector Linac

emittance, target, electron, positron

304

Y. Seimiya, N. Iida, T. Kamitani, M. Satoh
KEK, Ibaraki, Japan

In SuperKEKB linac, stable high charged low emittance beam is necessary. Transported beam to SuperKEKB Main Ring (MR) must be stable to the extent that the beam can be injected inside MR acceptance. SuperKEKB requirement must be satisfied for emittance including beam phase space jitter, called as effective emittance. Large amplitude beam position jitter has been measured at linac end. We evaluated that the effect of the beam position jitter on effective emittance and investigated the source of the beam phase space jitter.

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MOPMF076

Energy Spread Compensation in Arbitrary Format Multi-Bunch Acceleration With Standing Wave and Traveling Wave Accelerators

beam-loading, acceleration, positron, cavity

307

M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan

In the E-driven ILC (International Linear Collider) positron source, the beam is generated and accelerated in a multi-bunch format with mini-trains. The macro-pulse contains 2 to 8 mini-trains with several train gaps, because the pulse format is a copy of a part of the bunch storage pattern in DR (Damping Ring). This pulse format causes a variation of the accelerator field in the pulse due to the transient beam loading and an intensity fluctuation of captured positron. In this article, we discuss the compensation of the energy spread of such beam in standing wave and traveling wave accelerators. For standing wave accelerator, it can be compensated by switching input RF at appropriate timings. For traveling wave accelerator, it can be compensated by amplitude modulation of the input RF.

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MOPMF084

The Progress of CEPC Positron Source Design

positron, target, electron, collider

319

C. Meng, X.P. Li, G. Pei, J.R. Zhang
IHEP, Beijing, People's Republic of China

Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory. The injector is composed of 10 GeV linac and 120 GeV booster. The linac of CEPC is a normal conducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV and repetition frequency in 100 Hz. The positron source of CEPC is composed of target, flux concentrator, pre-accelerating section and beam separation system. The detailed design of each section of positron source will be presented and discussed, meanwhile the start-to-end dynamic simulation results will be presented also in this paper.

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MOPMK015

Development of a Bunched-Beam Electron Cooler for the Jefferson Lab Electron-Ion Collider

electron, kicker, gun, cathode

382

S.V. Benson, Y.S. Derbenev, D. Douglas, F.E. Hannon, A. Hutton, R. Li, R.A. Rimmer, Y. Roblin, C. Tennant, H. Wang, H. Zhang, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177.
Jefferson Lab is in the process of designing an electron-ion collider with unprecedented luminosity at a 65 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. We will present a new design for a Circulator Cooler Ring for bunched-beam electron cooling. This requires the generation and transport of very high-charge magnetized bunches, acceleration of the bunches in an energy recovery linac, and transfer of these bunches to a circulating ring that passes the bunches 11 times through the proton or ion beam inside cooling solenoids. This design requires the suppression of the effects of space charge and coherent synchrotron radiation using shielding and RF compensation.

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MOPML014

Status of the Commissioning of the LIGHT Prototype

DTL, MMI, rfq, proton

425

A. Degiovanni, J. Adam, D. Aguilera Murciano, S. Ballestrero, A. Benot-Morell, R. Bonomi, F.C.M. Cabaleiro Magallanes, M. Caldara, G. D'Auria, G. De Michele, M. Esposito, S. Fanella, D. Fazio, D.A. Fink, Y. Fusco, M. Gonzalez, P. Gradassi, A. Jeff, L. Kobzeva, G. Levy, G. Magrin, A. Marraffa, A. Milla, R. Moser, P. Nadig, G. Nuessle, A. Patino-Revuelta, T. Rutter, F. Salveter, A. Samoshkin, L. Wallet
A.D.A.M. SA, Meyrin, Switzerland
M. Cerv, V.A. Dimov, L.S. Esposito, S. H. Gibson, M. Giunta, Ye. Ivanisenko, V. F. Khan, S. Magnoni, C. Mellace, J.L. Navarro Quirante, H. Pavetits, PPA. Paz Neira, P. Stabile, K. Stachyra, D. Ungaro, A. Valloni, C. Zannini
AVO-ADAM, Meyrin, Switzerland

The company A.D.A.M. (Application of Detectors and Accelerators to Medicine), a CERN spin-off, is working on the construction and testing of its first linear accelerator for medical application: LIGHT (Linac for Image-Guided Hadron Therapy). LIGHT is an innovative high frequency proton linac designed to accelerate proton beams up to 230 MeV for protontherapy applications. The LIGHT accelerator consists of three different linac sections: a 750 MHz Radio Frequency Quadrupole (RFQ) accelerating the beam up to 5 MeV; a 3 GHz Side Coupled Drift Tube Linac (SCDTL) up to 37.5 MeV; and a 3 GHz Cell Coupled Linac (CCL) section up to 230 MeV. The compact and modular design is based on cutting edge technologies developed for particle colliders and adapted to the needs of hadron therapy beams. A prototype of LIGHT is presently under commissioning at CERN. This paper describes the design aspects and the different stages of installation and commissioning of the LIGHT prototype with emphasis on beam tests results obtained during the past year at different energies.

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MOPML015

Simulations and Measurements of the CCL Modules of the LIGHT Accelerator

coupling, proton, GUI, cavity

429

V. F. Khan, G. De Michele, S. Fanella, S. H. Gibson, Ye. Ivanisenko, C. Mellace, J.L. Navarro Quirante, C. Zannini
AVO-ADAM, Meyrin, Switzerland
M. Esposito, P. Gradassi
CERN, Geneva, Switzerland

A 230 MeV proton LINAC system for medical applications is being developed and commissioned for the LIGHT (Linac Image Guided Hadron Therapy) project by AVO-ADAM. The LINAC system consists of a 750 MHz RFQ (Radio frequency quadrupole) for the low energy proton acceleration, 2998 MHz SCDTL (Side Coupled Drift Tube Linacs) for the medium energy and 2998 MHz CCL (Coupled Cavity Linacs) for the high energy. In particular, the CCL accelerating modules are used in the energy range from 37.5 - 230 MeV. In this paper we discuss the 3D EM (electro-magnetic) simulation results and measurements of the CCL modules.

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MOPML017

Status and Development of the MYRRHA Injector

cavity, diagnostics, MMI, rfq

432

D. Mäder, H. Höltermann, D. Koser, B. Koubek, K. Kümpel, P. Müller, U. Ratzinger, M. Schwarz, W. Schweizer
BEVATECH, Frankfurt, Germany
C. Angulo, J. Belmans, D. Davin, W. De Cock, P. Della Faille, F. Doucet, A. Gatera, Pompon, F.F. Pompon, D. Vandeplassche
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
M. Busch, H. Hähnel, H. Podlech
IAP, Frankfurt am Main, Germany

The MYRRHA project aims at coupling a cw 600 MeV, 4 mA proton linac with a sub-critical reactor as the very first prototype nuclear reactor to be driven by a particle accelerator (ADS). Among several applications, MYRRHA main objective is to demonstrate the principle of partitioning and transmutation (P&T) as a viable solution to drastically reduce the radiotoxicity of long-life nuclear waste. For this purpose, the linac needs an unprecedented level of reliability in terms of allowable beam trips. The normal conducting injector delivers 16.6 MeV protons to the superconducting main linac. The first section of the injector (up to 5.9 MeV) consists of an ECR source, a 4-Rod-RFQ and a rebunching line followed by 7 individual CH-type cavities. This entire section will be set up and operated by SCK·CEN in Louvain-la-Neuve, Belgium, for ample performance and reliability testing. The first CH cavity has been sent for power tests to IAP Frankfurt, Germany. The most recent status of all cavities, couplers and the beam diagnostics of the MYRRHA injector is presented in this paper.

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MOPML022

Development of Travelling Wave Accelerating Structure for a 10 MeV E-Linac

electron, bunching, radiation, simulation

443

J.H. Yang, Y. Yang
CIAE, Beijing, People's Republic of China
G. Han
China Institute of Atomic Energy, Beijing, People's Republic of China

Electron irradiation processing is a vital application field of nuclear technology application. China Institute of Atomic Energy (CIAE) developed several 10 MeV high power electron irradiating accelerator successfully, promoting the development of high energy high power irradiating accelerator technology and electron irradiation processing in China. The paper introduced the development of a 10 MeV travelling wave accelerating tube. The tube operates at 2856 MHz in 2π/3 mode. The SUPERFISH and PARMELA are used for the physical design. Several methods are used for microwave parameter measurement and tuning. The high power test shows the beam energy is 10.3 MeV and average beam power is 24.3 kW.

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MOPML027

Status of Carbon Commissioning of the MedAustron Therapy Accelerator

MMI, synchrotron, ion-source, rfq

457

C. Schmitzer, L. Adler, A. De Franco, F. Farinon, N. Gambino, G. Guidoboni, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, I. Strašík, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria
L.C. Penescu
Abstract Landscapes, Montpellier, France

The MedAustron therapy accelerator is intended to treat cancer patients with proton and carbon beams of 62-252 MeV and 120-400 MeV respectively. The accelerator features three Supernanogan ECR ion sources, a 400 keV/u RFQ and a 7 MeV/u interdigital H-mode Linac. A middle energy beam transfer line also serves as injector into a 77m synchrotron from which the beam may be transferred to 4 different irradiation rooms, 3 of which are dedicated to medical treatment. The therapy accelerator is in clinical operation since end 2016 and is currently solely configured for the use of protons. The next clinical objective is to enable treatments using C⁶⁺ ions which triggered the carbon commissioning of the accelerator in 2017. This paper will discuss the latest results from carbon commissioning in the different sections of the accelerator, achieved efficiencies and outlook on future carbon activities.

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MOPML028

Accelerator Machines and Experimental Activities in the ENEA Frascati Particle Accelerators and Medical Application Laboratory

radiation, experiment, proton, electron

460

M. Vadrucci, A. Ampollini, G. Bazzano, F. Borgognoni, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti, E. Trinca
ENEA C.R. Frascati, Frascati (Roma), Italy

Funding: Regione Lazio - TOP IMPLART Project
In the ENEA Frascati research center the APAM (Particle Accelerators and Medical Application) laboratory is devoted to the development of particle accelerators for medical applications. Two main facilities are operational. The TOP-IMPLART proton accelerator is a pulsed fully linear machine aimed at active intensity modulated proton therapy with a final energy of 150 MeV. The machine offers two beam extraction points: one at 3-7 MeV, on a vertical line, and the other one at 35 MeV, the maximum energy currently available, with a pulse current up to 35 μA, on the horizontal line. The REX (Removable target Electron X-ray) source consists of an electron standing wave LINAC generating a beam in the energy range of 3 to 5 MeV with a pulsed current of 0.2 A. This source can generate Bremsstrahlung X-ray beams using suitable converters (Pb, W, Ta). This paper describes the experimental results of satellite activities performed in these facilities in the fields of biology, dosimetry, electronics, PIXE spectroscopy and preservation of cultural heritage manufacts.

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MOPML031

Highlights of Accelerator Activities in France on Behalf of the Accelerator Division of the French Physics Society

laser, proton, operation, electron

470

J.-L. Revol
ESRF, Grenoble, France
S. Chel
CEA/IRFU, Gif-sur-Yvette, France
B. Cros
CNRS LPGP Univ Paris Sud, Orsay, France
N. Delerue
LAL, Orsay, France
E. Giguet
ALSYOM, Versailles, France
V. Le Flanchec
CEA/DAM, Bruyères-le-Châtel, France
L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France
L. Perrot
IPN, Orsay, France
A. Savalle
GANIL, Caen, France
T. Thuillier
LPSC, Grenoble Cedex, France

The French Physical Society is a non-profit organization working to advance and diffuse the knowledge of physics. Its Accelerators division contributes to the promotion of accelerator activities in France. This paper presents the missions and actions of the division, high-lighting those concerning young scientists. A brief presentation of the laboratories, institutes, and facilities that are the main actors in the field is given. Significant ongoing and planned projects in France are described, including medical applications. Main French contributions in inter-national projects are then listed. Finally, cultural and technical relationships between industry and laboratories are discussed.

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MOPML032

Prospects for a Muon Spin Resonace Facility in the Fermilab MuCool Test Area

target, experiment, timing, resonance

474

J.A. Johnstone, C. Johnstone
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Reserach Alliance, LLC under Contract no. DE-AC02-07CH11359 with the United States Department of Energy.
This paper investigates the feasibility of re-purposing the MuCool Test Area beamline and experimental hall to support a Muon Spin Resonance Facility which would make it the only such facility in the US. This report reviews the basic muon production concepts as studied and operationally implemented at TRIUMF, PSI, and RAL and their application in the context of the MTA facility. Two scenarios were determined feasible. One, an initial minimal-shielding and capital-cost investment stage with a single secondary muon beamline that utilizes an existing primary beam absorber and, another, an upgraded stage, that implements an optimized production target, a proximate high-intensity absorber, and optimized secondary muon lines. A unique approach is proposed which chops or strips a macropulse of H⁻ beam into a micropulse substructure - a muon creation timing scheme - which allows Muon Spin Resonance experiments in a linac environment. With this timing scheme, and attention to target design and secondary beam collection, the MTA can host enabling and competitive Muon Spin Resonance experiments.

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MOPML033

Data Supply of Accelerator Devices - Data Management of Device Process Data at a Medical Accelerator

controls, database, operation, MMI

477

M. Galonska, R. Cee, Th. Haberer, K. Höppner, J.M. Mosthaf, A. Peters, S. Scheloske, C. Schömers
HIT, Heidelberg, Germany

HIT is the first dedicated proton and carbon cancer therapy facility in Europe. It uses the full 3D intensity controlled raster scanning dose delivery method of pencil beams with ion beams of 48 - 430 MeV/u provided by a linac-synchrotron-system. Ion beams in this wide range of energies, different beam sizes, and intensities have to be provided by the control system to all treatment rooms at any time with high accuracy, stability, and reproducibility. This paper briefly reflects some aspects of the data supply, i. e. the settings of accelerator devices at a medical accelerator. This includes the generation of control data, storage, and data recovery routines, which have been developed at HIT in the recent years. That is in particular the management of verified therapy data and settings, which are stored in a non-volatile memory of the device controllers, and – as a backup – in a database and which are protected against unintended changes for safety reasons.

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MOPML043

High Gradient Performance of an S-Band Backward Traveling Wave Accelerating Structure for Medical Hadron Therapy Accelerators

proton, cavity, radiation, accelerating-gradient

491

A. Vnuchenko, C. Blanch Gutiérrez, D. Esperante Pereira
IFIC, Valencia, Spain
S. Benedetti, N. Catalán Lasheras, A. Grudiev, B. Koubek, G. McMonagle, I. Syratchev, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland
A. Faus-Golfe
LAL, Orsay, France
T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
S. Pitman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

The high-gradient performance of an accelerating structure prototype for a medical proton linac is presented. The structure was designed and built using technology developed by the CLIC collaboration and the target application is the TULIP (Turning Linac for Proton therapy) proposal developed by the TERA foundation. The special feature of this design is to produce gradient of more than 50 MV /m in low-β accelerating structures (v/c=0.38). The structure was tested in an S-band test stand at CERN. During the tests, the structure reached over above 60 MV/m at 1.2 μs pulse length and breakdown rate of about 5x10^-6 bpp. The results presented include ultimate performance, long term behaviour and measurements that can guide future optimization.

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MOPML044

Start-to-End Beam Dynamic Simulations for PRAE

gun, emittance, laser, solenoid

495

A. Vnuchenko
IFIC, Valencia, Spain
C. Bruni, M. El Khaldi, A. Faus-Golfe, P. Lepercq, C. Vallerand
LAL, Orsay, France
A. Latina
CERN, Geneva, Switzerland

The PRAE project (Platform for Research and Applications with Electrons) aims at creating a multidisciplinary R&D facility in the Orsay campus gathering various scientific communities involved in radiobiology, subatomic physics, instrumentation and particle accelerators around an electron accelerator delivering a high-performance beam with energy up to 70 MeV and later 140 MeV, in order to perform a series of unique measurements and future challenging R&D. In this paper we report the first start-to-end simulations from the RF gun, going through the linac and finally to the different experimental platforms. The beam dynamics simulations have been performed using a concatenation of codes. In particular for the linac the RF-Track code recently developed at CERN will be used and benchmarked. The different working points have been analysed in order to minimise the transverse emittance and the beam energy spread including space charge effects at low electron energies.

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MOPML052

The Path to Compact, Efficient Solid-State Transistor-Driven Accelerators

cavity, electron, impedance, simulation

520

D.C. Nguyen, C.E. Buechler, G.E. Dale, R.L. Fleming, M.A. Holloway, J.W. Lewellen, D. Patrick
LANL, Los Alamos, New Mexico, USA
V.A. Dolgashev, E.N. Jongewaard, E.A. Nanni, J. Neilson, A.V. Sy, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: Research presented in this work is supported by (LANL) Laboratory Directed Research and Development 20170521ER and by (SLAC) Department of Energy contract DE-AC02-76SF00515.
Small, lightweight, few-MeV electron accelerators that can operate with low-voltage power sources, e.g., solid-state transistors running on 50 VDC, instead of high-voltage klystrons, will provide a new tool to enhance existing applications of accelerators as well as to initiate new ones. Recent advances in gallium nitride (GaN) semiconductor technologies * have resulted in a new class of high-power RF solid-state devices called high-electron mobility transistors (HEMTs). These HEMTs are capable of generating a few hundred watts at S-, C- and X-bands at 10% duty factor. We have characterized a number of GaN HEMTs and verified they have suitable RF characteristics to power accelerator cavities **. We have measured energy gain as a function of RF power in a single low-beta C-band cavity. The HEMT powered RF accelerators will be compact and efficient, and they can operate off the low-voltage DC power buses or batteries. These all-solid-state accelerators are also more robust, less likely to fail, and are easier to maintain and operate. In this poster, we present the design of a low-beta, 5.1-GHz cavity and beam dynamics simulations showing continuous energy gain in a ten-cavity C-band prototype.
* See for example, http://www.wolfspeed.com/downloads/dl/file/id/463/product/174/cghv59350.pdf
** J.W. Lewellen et al., Proceedings of LINAC2016, Paper MO3A03

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MOPML055

Preliminary Physics Design of a Linac with the Variable Energy for Industrial Applications

electron, gun, beam-loading, simulation

530

Zh. X. Tang
USTC, Hefei, Anhui, People's Republic of China
L. Wang, D.R. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

This paper describes the physics design of a S-band (2856 MHz) linear accelerator (linac) with variable energy tuning. The system consists of a DC gun for generating electron, prebuncher for velocity modulation and two travelling wave (TW) accelerating sections for acceleration. The accelerating structure is a 2'Ð/3 mode constant gradient TW structure, which comprises TW buncher cells, followed by uniform cells. The structure is designed to accelerate 45 keV electron beam from the electron gun to 3.2 MeV, and then 10 MeV. An important feature of the TW linac is that the RF output power of the first linac is as the RF input power of the second linac. Three dimensional transient simulations of the accelerating structure along with the input and output couplers have been performed to explicitly demonstrate this feature. Beam dynamics is performed to calculate the beam parameter.

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MOPML058

Comparison of Water Absorbed Dose for Photons of Linac and Traceability System for Radiotherapy in China

photon, controls, radiation, electron

537

K. Wang, S. Jin, Z. Wang, J. Zhang
National Institute of Metrology, Beijing, People's Republic of China

National Institute of Metrology (NIM) developed the standards of the absorbed dose to water for high-energy photon and electron beams, to support the PSDL and SSDL calibration capability in China. After the measurement of absorbed dose to water for 6, 10, and 25 MV photons of linac, NIM took part the BIPM. RI(I).K6 comparison with the Bureau International des Poids et Mesures (BIPM). The tissue phantom ratio (TPR_20,10) of 6MV and 10MV photons were measured by IBA CC13 chamber and Keithley 6517B with different output dose of the Linac, and also calculated by the dose ratio (D₂0⁄D₁0) with the formula in IAEA TRS-398 report. TPR_20,10 measured directly is 0.3% larger than calculated by the dose ratio D₂0⁄D₁0 . The absorbed dose to water is measured by water calorimeter with the combined standard uncertainty of 0.35%. The discrepancy of absorbed dose to water measured separately by open and sealed vessel is 0.2% at 10MV. The K6 comparison was done, the results reported as ratios of the NIM and the BIPM evaluations (and with the combined standard uncertainties given in parentheses), are 0.9917(60) at 6 MV, and 0.9941(59) at 10 MV. The quality correction factor KQ of usual used chamber was measure directly, and it is 0.3%~0.7% smaller than the data in the IAEA TRS-398 report. The typical chamber-to-chamber variations of the dose obtained with the IAEA TRS-277, TRS-398 and AAPM TG-51 were between 0.2% and 1.0% for the different photon beams. The variations of the dose obtained with IAEA TRS-398 and chambers calibrated directly by megavoltage photons were between 0.1% to 0.8%. The new standard can achieve the traceability of water absorbed dose for MV photons and will significantly reduce the uncertainty of ion chamber calibrations for Chinese radiotherapy centers.

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MOPML067

9/6 MeV European S-band Linac Structure for Container Inspection System at RTX and KAERI

electron, coupling, bunching, gun

560

P. Buaphad, H.D. Park, S. Song
RTX, Daejeon, Republic of Korea
P. Buaphad, Y. Joo
University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
P. Buaphad, S.C. Cha, Y. Joo, Y. Kim, H.R. Lee
KAERI, Jeongeup-si, Republic of Korea

Recently, demands on low energy electron linear accelerators (linacs) for industrial applications are rapidly growing. Their beam energies are lower than 20 MeV, and they require a compact, cheap, and stable accelerator system. For the Container Inspection System (CIS), KAERI successfully developed a 9/6 MeV American S-band (= 2856 MHz) linac with a 5 MW klystron in 2013. To reduce the cost of the RF source, recently, KAERI and RTX also have been developing another 9/6 MeV European S-band (= 2998 MHz) linac by using a magnetron with a lower RF power of about 3.1 MW. Its accelerating structure is designed to be operated in π/2 mode by coupling 13 accelerating cells together through 12 side-coupling cells. The CST Microwave Studio is used for electromagnetic simulations and optimization of the accelerating structure. After various optimizations, a shunt impedance of 84 MΩ/m is obtained at π/2 mode frequency of 2998.31 MHz. In this paper, we describe design concept, optimization, and RF measurement of the new 9/6 MeV European S-band linac structure. Then, we compare it with our old American S-band linac structure.

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TUYGBE2

CBETA, the 4-Turn ERL with SRF and Single Return Loop

electron, gun, SRF, cryomodule

635

G.H. Hoffstaetter, N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, C. Liu, G.J. Mahler, F. Méot, R.J. Michnoff, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
BNL, Upton, Long Island, New York, USA
D. Douglas
JLab, Newport News, Virginia, USA
J.K. Jones
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Jusic
Cornell University, Ithaca, New York, USA
D.J. Kelliher
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
B.C. Kuske, M. McAteer, J. Völker
HZB, Berlin, Germany

Funding: Supported by NSF award DMR-0807731, DOE grant DE-AC02-76SF00515, and NYSERDA.
A collaboration between Cornell University and Brookhaven National Laboratory has designed and is constructing CBETA, the Cornell-BNL ERL Test Accelerator on the Cornell campus. The ERL technology that has been prototyped at Cornell for many years is being used for this new accelerator, including a DC electron source and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current linac cryomodule optimized for ERLs, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams. BNL has designed multi-turn ERLs for several purpose, dominantly for the electron beam of eRHIC, its Electron Ion Collider (EIC) project and for the associated fast electron cooling system. Also in JLEIC, the EIC designed at JLAB, an ERL is envisioned to be used for electron cooling. The number of transport lines in an ERL is minimized by using return arcs that are comprised of a Fixed Field Alternating-gradient (FFA) design. This technique will be tested in CBETA, which has a single return for the 4-beam energies with strongly-focusing permanent magnets of Halbach type. The high-brightness beam with 150~MeV and up to 40~mA will have applications beyond accelerator research, in industry, in nuclear physics, and in X-ray science. Low current electron beam has already been sent through the most relevant parts of CBETA, from the DC gun through both cryomodules, through one of the 8 similar separator lines, and through one of the 27 similar FFA structures. Further construction is envisioned to lead to a commissioning start for the full system early in 2019.

Slides TUYGBE2 [17.343 MB]

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TUPAF001

Requirements for the Cryogenic Refrigerator and the He Distribution System for the MYRRHA 100 Mev Accelerator

cryogenics, cavity, cryomodule, operation

655

T. Junquera
Accelerators and Cryogenic Systems, Orsay, France
C. Angulo
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
D. Vandeplassche
SCK•CEN, Mol, Belgium

MYRRHA is an ADS demonstrator for the long-lived radioactive waste transmutation. It is composed of a High Energy CW Linac Accelerator (600 MeV - 4mA) coupled to a Subcritical Reactor of 100 MW thermal power. The main challenge of the Linac is a very high reliability performance to limit stress and long restart procedures of the reactor. Within the MYRRHA project phased approach for the construction, a 100 MeV-4 mA Linac (Injector up to 17 MeV and SC Linac between 17 MeV and 100 MeV) will be constructed in the Phase 1, covering 2016-2024. The SC Linac is composed of 58 Single-Spoke SC cavities, housed in 29 cryomodules. The cavities operates at 352 MHz, in a superfluid Helium bath at 2K. In this paper, the requirements for the Linac Cryogenic System are presented. The analysis of high thermal loads induced by the CW mode operation of cavities, leads to a Cryogenic Refrigerator with a power of 2700 W (equiv. power capacity at 4.5 K). Each cryomodule is connected through a dedicated Valve Box to the Helium transfer line running along the Linac tunnel. A description of the cryogenic system features and initial models of the tunnel and associated buildings are presented.

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TUPAF002

Beam Commissioning of the 750 MHz Proton RFQ for the LIGHT Prototype

rfq, MMI, emittance, diagnostics

658

V.A. Dimov, M. Caldara, A. Degiovanni, L.S. Esposito, D.A. Fink, M. Giunta, A. Jeff, A. Valloni
AVO-ADAM, Meyrin, Switzerland
A.M. Lombardi, S.J. Mathot, M. Vretenar
CERN, Geneva, Switzerland

ADAM (Application of Detectors and Accelerators to Medicine), a CERN spin-off company, is developing the Linac for Image Guided Hadron Therapy, LIGHT, which will accelerate proton beams up to 230 MeV. The design of the linac will allow fast intensity and energy modulation for pencil-beam scanning during cancer treatment. The linac consists of a 40 keV Proton Injector; a 750 MHz Radio Frequency Quadrupole (RFQ) accelerating the proton beam up to 5 MeV; a 3 GHz Side Coupled Drift Tube Linac (SCDTL) up to 37.5 MeV; and a 3 GHz Cell Coupled Linac (CCL) section up to 230 MeV. A prototype of LIGHT is being commissioned progressively with the installation of the accelerating structures at a CERN site. The beam commissioning of the RFQ, which was designed and built by CERN, was completed in 2017 using a movable beam diagnostic test bench with various instruments. This paper reports on the RFQ commissioning strategy and the results of the beam measurements.

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TUPAF003

Integrated Prototyping in View of the 100 MeV Linac for Myrrha Phase 1

cryomodule, cavity, controls, target

661

D. Vandeplassche, J. Belmans
SCK•CEN, Mol, Belgium
C. Angulo, D. Davin, W. De Cock, P. Della Faille, F. Doucet, A. Gatera, Pompon, F.F. Pompon
Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
D. Bondoux, F. Bouly
LPSC, Grenoble Cedex, France
H. Höltermann, D. Mäder
BEVATECH, Frankfurt, Germany
C. Joly, G. Olry, H. Saugnac
IPN, Orsay, France
M. Loiselet, N. Postiau, L. Standaert
UCL, Louvain-la-Neuve, Belgium
H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: Work partially supported by the European Commission H2020 programme MYRTE #662186
The MYRRHA project borne by SCK•CEN, the Belgian Nuclear Research Centre, aims at realizing a pre-industrial Accelerator Driven System (ADS) for exploring the transmutation of long lived nuclear waste. The linac for this ADS will be a High Power Proton Accelerator delivering 2.4 MW CW beam at 600 MeV. It has to satisfy stringent requirements for reliability and availability: a beam-MTBF of 250h is targeted. The reliability goal is pursued through a phased approach. During Phase 1, expected till 2024, the MYRRHA linac up to 100 MeV will be constructed. It will allow to evaluate the reliability potential of the 600 MeV linac. It will also feed a Proton Target Facility in which radioisotopes of interest will be collected through an ISOL system. This contribution will focus on the transition to integrated prototyping, which will emphasize (i) a test platform consisting of the initial section of the normal conducting injector (5.9 MeV), (ii) the realization of a complete cryomodule for the superconducting linac and of its cryogenic valve box. The cryomodule will house two 352 MHz single spoke cavities operated at 2K.

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TUPAF014

Beam Dynamics Studies For the IFMIF-DONES SRF-Linac

SRF, cryomodule, cavity, solenoid

687

L. Du, N. Bazin, N. Chauvin, S. Chel, J. Plouin
CEA/IRFU, Gif-sur-Yvette, France

The DONES (DEMO oriented neutron source) project is aimed at constructing a DEMO of IFMIF to provide sufficient material damage [1]. In the SRF-Linac of this project, losses can cause harmful material activation and must be maintained much less than 1W/m. It's a challenge to keep losses at such a low level with high beam power and high space charge. This paper presents two designs of the DONES SRF-Linac, one with 4 cryomodules and another with 5 cryomodules. The design details to reduce the losses and the multi-particle simulation results will be shown. The errors studies for these results will also be discussed.

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TUPAF017

Stability Analysis of the TOP-IMPLART 35 MeV Proton Beam

DTL, proton, klystron, booster

697

P. Nenzi, A. Ampollini, G. Bazzano, L. Picardi, C. Ronsivalle, V. Surrenti, E. Trinca, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy

Funding: The TOP-IMPLART program is funded by Regione Lazio.
The TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTherapy) is the demonstrator of a 150 MeV proton linear accelerator devoted to cancer treatment application under development at ENEA-Frascati. It is a full linear machine composed by a 425 MHz 7 MeV injector and a high frequency linac operating at 2997.92 MHz. The first accelerating section, installed and in operation, consists of 4 SCDTL structures and delivers a 35 MeV beam in 3 microseconds pulses at a maximum repetition frequency of 50 Hz. The principal advantage of a linear accelerator, in a therapeutic application, is the quick setting possibility (up to pulse-to-pulse, in principle) of the physical properties of the proton beam, offering larger flexibility (compared to traditional circular designs) and improved precision on dose delivery to the patient., The short and long range stability of the machine have been analyzed measuring on a pulse by pulse basis both the output beam characteristics and other machine parameters in order to identify those that mainly affect the beam stability. This work describes the methodology used in this study, the main results achieved and the future developments.

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TUPAF018

Characterization of Automatic Frequency Control systems for S-band Proton LINAC "TOP-IMPLART"

DTL, controls, proton, detector

701

G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy

The TOP-IMPLART (Intensity Modulated Proton Linear Accelerator for RadioTherapy) proton linear accelerator is under development at ENEA-Frascati. It is composed by a 7 MeV, 425 MHz injector followed by a sequence of 2997.92 MHz accelerating modules. Four 10 MW klystrons will be used to power all high frequency structures up to a beam energy of 150 MeV. The first section, consisting of 4 SCDTL modules (7 to 35 MeV), is operational at low repetition rate (up to 50 Hz). Whereas beam acceleration is effective even without closed loop control, to ensure high beam current stability the resonance frequency variation must be kept for each SDCTL module within few kHz. This is achieved implementing an automatic frequency control (AFC) loop that detects structure detuning caused by thermal drifts and produce an error signal fed to a tuning motor. A prototype of an AFC custom solution, derived from a medical electron linac, has been tested on TOP-IMPLART accelerator. This was originally designed for magnetron frequency tuning with much larger frequency span. Other AFC systems with different components have been evaluated in order to reach the high required resolution.

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TUPAF020

Performance of the CERN Low Energy Ion Ring (LEIR) with Xenon beams

injection, MMI, controls, extraction

705

R. Alemany-Fernández, S.C.P. Albright, O. Andujar, M.E. Angoletta, J. Axensalva, H. Bartosik, G. Baud, N. Biancacci, M. Bozzolan, S. Cettour Cave, K. Cornelis, J. Dalla-Costa, M. Delrieux, A. Dworak, A. Findlay, F. Follin, A. Frassier, M. Gabriel, A. Guerrero, M. Haase, S. Hirlaender, S. Jensen, V. Kain, L.V. Kolbeck, Y. Le Borgne, D. Manglunki, O. Marqversen, S. Massot, D. Moreno Garcia, D.J.P. Nicosia, S. Pasinelli, L. Pereira, D. Perez, A. Rey, J.P. Ridewood, F. Roncarolo, A. Saá Hernández, R. Scrivens, O.G. Sveen, G. Tranquille, E. Veyrunes
CERN, Geneva, Switzerland

In 2017 the CERN Low Energy Ion Ring demonstrated once more the feasibility of injecting, accumulating, cooling and accelerating a new nuclei, 129Xe39 . The operation of this new ion species started at the beginning of March with the start up of the xenon ion source and the Linac3. Ten weeks later the beam arrived to the Low Energy Ion Ring (LEIR) triggering the start of several weeks of beam commissioning in view of providing the injector complex with Xenon beams for different experiments and a series of machine development experiments in LEIR. Two types of beams were setup, the so called EARLY beam, with a single injection into LEIR from Linac3, and the NOMINAL beam with up to seven injections. 2017 was as well an interesting year for LEIR because several improvements in the control system of the accelerator and in the beam instrumentation were done in view of increasing the machine reliability. This paper summarises the beam commissioning phase and all the improvements carried out during 2017.

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TUPAF034

LEIR Injection Efficiency Studies as a Function of the Beam Energy Distribution from Linac3

injection, cavity, bunching, optics

758

S. Hirlaender, R. Alemany-Fernández, H. Bartosik, G. Bellodi, N. Biancacci, V. Kain, R. Scrivens
CERN, Geneva, Switzerland

High intensities in the CERN Low Energy Ion Ring (LEIR) are achieved using multi-turn injections from the pre-accelerator Linac3 combined with simultaneous stacking in momentum and transverse phase spaces. Up to seven consecutive 200 μs long, 200 ms spaced pulses are injected from Linac3 into LEIR by stacking each of them into the six-dimensional phase-space over 70 turns. An inclined septum magnet allows proper filling of the transverse phase-space plane, while longitudinal stacking requires momentum variation achieved by a shift of mean momentum over time provided by phase shifting a combination of 2 RF cavities at the exit of Linac3. The achievable maximum accumulated intensity depends strongly on the longitudinal beam quality of the injected beam. The longitudinal Schottky signal is used to measure the received energy distribution of the circulating beam which is then correlated with the obtained injection efficiency. This paper presents the experimental studies to understand and further improve the injection reliability and the longitudinal stacking.

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TUPAF036

Studies of the Injection and Cooling Efficiency in LEIR Using the Longitudinal Schottky Spectrum

injection, diagnostics, electron, pick-up

765

S. Hirlaender, R. Alemany-Fernández, H. Bartosik, N. Biancacci, V. Kain
CERN, Geneva, Switzerland

The CERN Low Energy Ion Ring (LEIR) has two main operational beams with their associated cycles, the so-called EARLY and the NOMINAL beam. The EARLY beam consists of a single injected pulse from the LINAC3 accelerator, whereas seven consecutive injections are accumulated, and electron cooled for the NOMINAL beam. In both cases, the longitudinal Schottky monitor allows assessing the longitudinal particle distribution during the cooling process on the injection plateau. A method has been established to analyze the Schottky signal, reconstruct the initial particle momentum distribution and derive relevant parameters such as the cooling time, energy off-set of injected and stacked beam or the momentum distribution of the lost beam. The variations of the obtained parameters and the impact on the LEIR performance will be addressed.

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TUPAF042

Characterization of the Beam Energy Spread at the REX/HIE-ISOLDE Linac

cavity, ISOL, experiment, detector

787

M.L. Lozano, N. Bidault, E. Fadakis, M.A. Fraser, E. Matli, J.A. Rodriguez
CERN, Geneva, Switzerland

ISOLDE is an on-line radioactive isotope separator located at CERN that works by colliding protons accelerated in the PS Booster into a fixed target and by separating the resultant ionized isotopes using a magnetic separator. The completion of the HIE-ISOLDE superconducting linac allows the acceleration of these ions to energy levels that were not reachable before, opening the door to new experiments in different fields. These experiments often have special requirements in terms of beam intensity and purity, transverse emittance or energy spread. A possible way to reduce the energy spread of the beam delivered to the experimental stations is to use one or more of the superconducting cavities as bunchers. The main results of several tests conducted during the last beam commissioning campaign prove that this mode of operation is feasible and will be presented in this paper.

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TUPAF044

Schedule Evolution of the Linac4 Installation During the Lifetime of the Linac4 Project and Connection Forecast

civil-engineering, MMI, status, site

794

J. Coupard, A. Berjillos, J.-P. Corso, K. Foraz, B. Nicquevert, E. Paulat, M. Vretenar
CERN, Geneva, Switzerland

The new CERN linear accelerator Linac4 started the installation phase in 2010 after the delivery of the new building and tunnel by the civil engineering and was inaugurated six years later. It will be connected to the CERN accelerators chain and replace the current proton linear accelerator, Linac2, during the second long shut-down (LS2) of the Large Hadron Collider (LHC) in 2019. This paper aims to summarize the schedule evolution through the different phases of installation, from general services to machine installation, highlight the key factors that contributed to drive the schedule (safety, logistics and integration) and describe the coordination study of the future connection (integration, schedule, logistics, constraints and priorities).

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TUPAF062

Parametric Study of the Beam Footprint Characteristics on the ESS Target

target, HOM, ion-source, operation

866

R. Miyamoto
ESS, Lund, Sweden
H.D. Thomsen
ISA, Aarhus, Denmark

The beam delivery system of the ESS linac utilizes fast oscillating triangular wave dipole magnets of two transverse planes (raster magnets) to spray each long beam pulse (2.86 ms) over a rectangular cross-check pattern on the target. The characteristics of this beam footprint on the target are determined by the amplitudes of the raster magnets, RMS sizes of the beam and, in some case, the tail of the beam profile and have to satisfy the requirements from the target for the peak density as well as the fraction outside of a given rectangular boundary. This paper presents approximate closed-form expressions for the characteristics of the beam footprint and, based on the presented expressions, explores the parameter space of the raster magnets and beam parameters for achieving the optimal characteristics of the beam footprint.

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TUPAF063

Beam Dynamics Studies of the ESS LINAC Using a New Multicell Cavity Model

cavity, emittance, DTL, distributed

870

R. De Prisco, D.C. Plostinar
ESS, Lund, Sweden

The European Spallation Source is designed to deliver 5 MW proton beam power on the target while keeping the beam induced losses below 1 W/m throughout the LINAC. This implies the need of accurate models to correctly describe the longitudinal beam dynamics within the multi-cell cavities. In all the previous error studies the cells of a multi-cell cavity were modelled as a sequence of independent gaps and the errors were applied directly on the amplitude of each cell accelerating field, considered as random variable. In this paper, instead, we present a new detailed analysis of the effect of the error tolerances on the beam dynamics including a new model to calculate the amplitude errors of the accelerating field in the multi-cell cavities: errors are applied on the geometrical parameters of each cavity; then the accelerating field is calculated solving the Maxwell equations over all the cavity.

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TUPAF064

Preparation Towards the Ess Linac Ion Source and Lebt Beam Commissioning on Ess Site

MMI, rfq, solenoid, site

874

R. Miyamoto, M. Eshraqi, A. Jansson, E. Laface, Y. Levinsen, O. Midttun, N. Milas, M. Muñoz, D.C. Plostinar, A. Ponton, E. Sargsyan, L. Tchelidze
ESS, Lund, Sweden
L. Celona, L. Neri
INFN/LNS, Catania, Italy
W. Ledda
Vitrociset s.p.a, Roma, Italy

Beam commissioning of the proton linac of the European Spallation Source begin in summer, 2018, from the ion source (IS) and low energy beam transport (LEBT), and continues in stages until 2022, when the first beam is sent to its spallation target. This paper presents the plan, status, and highlights of preparation works for the upcoming IS and LEBT beam commissioning.

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TUPAF065

Opportunities and Challenges in Planning the Installation, Testing and Commissioning of Large Accelerator Facilities

MMI, DTL, target, neutron

878

D.C. Plostinar, D. Bergenholtz, H. Danared, L. Gunnarsson, M.I. Israelsson, A. Jansson, M. Lindroos, A. Sunesson, L. Tchelidze, J.G. Weisend
ESS, Lund, Sweden

Delivering major accelerator facilities requires complex project preparation, organisation and scheduling. Often, multiple factors have to be taken into account including technical, financial and political. This makes planning particularly difficult, but at the same time opens opportunities for improving and optimising the project prospects. In this paper, we discuss the major drivers governing the installation, testing and commissioning of major accelerators in general, with particular emphasis on the European Spallation Source (ESS) accelerator, currently under construction in Lund, Sweden.

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TUPAF074

Preliminary Modelling of Radiation Levels at the Fermilab PIP-II Linac

proton, GUI, booster, radiation

898

L. Lari, C.M. Baffes, S.J. Dixon, N.V. Mokhov, I.L. Rakhno, I.S. Tropin
Fermilab, Batavia, Illinois, USA
F. Cerutti, L.S. Esposito, L. Lari
CERN, Geneva, Switzerland

PIP-II is the Fermilab's flagship project for providing powerful, high-intensity proton beams to the laboratory's experiments. The heart of PIP-II is an 800-MeV superconducting linac accelerator. It will be located in a new tunnel with new service buildings and connected to the present Booster through a new transfer line. To support the design of civil engineering and mechanical integration, this paper provides preliminary estimation of radiation level in the gallery at an operational beam loss limit of 0.1 W/m, by means of Monte Carlo calculations with FLUKA and MARS15 codes.

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TUPAF076

Design of PIP-II Medium Energy Beam Transport

vacuum, SRF, kicker, cryomodule

905

A. Saini, C.M. Baffes, A.Z. Chen, V.A. Lebedev, L.R. Prost, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The Proton Improvement Plan-II (PIP-II) is a proposed upgrade for the accelerator complex at Fermilab. The central piece of PIP-II is a superconducting radio frequency (SRF) 800 MeV linac capable of operating in both CW and pulse regimes. The PIP-II linac comprises a warm front-end that includes a H⁻ ion source capable of delivering 15-mA, 30-keV DC or pulsed beam, a Low Energy Beam Transport (LEBT), a 162.5 MHz, CW Radio-Frequency Quadrupole (RFQ) accelerating the ions to 2.1 MeV and, a 14-m Medium Energy Beam Transport (MEBT) before beam is injected into SRF part of the linac. This paper presents the PIP-II MEBT design and, discusses operational features and considerations that lead to existing optics design such as bunch by bunch chopping system, minimization of radiation coming to the warm front-end from the SRF linac using a concrete wall, a robust vacuum protection system etc.

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TUPAF085

Status of Link Existing Facility Project for FAIR

shielding, operation, radiation, synchrotron

934

J. Stadlmann, C. Omet, A. Schuhmann, P.J. Spiller
GSI, Darmstadt, Germany

The project "Link existing Facility", or GaF (GSI Anbindung an FAIR), is an important subproject of the overall FAIR facility. In order to serve as injector for SIS100, the main accelerator of FAIR, the existing GSI synchrotron SIS18 is undergoing an upgrade program leading to about 100 times higher beam intensities. Especially the foreseen operation with 4 GeV Protons with up to 5·10¹² protons per second increases the radiation protection requirements to such an extent that the existing radiation protection measures are no longer sufficient. The project consists of 78 individual measures. The four most substantial activities are the construction of a table-like structure to carry additional shielding. The creation of an opening and a first part of transfer tunnel for the beamlines towards the future FAIR campus. The preparation for the building, beam dump and connection of the FAIR proton injector. The incorporation of state-of-the-art radiation- and fire-protection measures into the present facilities including the a new technical building to house technical infrastructure. We report on the project status which is foreseen to finish mid-2018.

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TUPAF086

Adaption of the HSI -RFQ Rf-Properties to an Improved Beam Dynamics Layout

simulation, rfq, operation, resonance

938

M. Vossberg, L. Groening, S. Mickat, H. Vormann, C. Xiao
GSI, Darmstadt, Germany
V. Bencini, J.M. Garland, J.-B. Lallement, A.M. Lombardi
CERN, Geneva, Switzerland

The GSI accelerator facility comprising the linear accelerator UNILAC and the synchrotron SIS18 will be used in future mainly as the injector for the Facility for Anti-Proton and Ion Research (FAIR) being under construction. FAIR requires high beam brilliance and the UNILAC's RFQ electrodes must be upgraded with respect to their beam dynamics design. The new layout is currently being conducted at CERN with the aim of adjusting the electrode voltage according to the design voltage of 123 kV. CST simulations performed at GSI assure that the resonance frequency with the new electrode geometry is recuperated through corrections of the carrier rings. Simulations on the frequency dependence of the rings shapes and their impact on the voltage distribution along the RFQ are presented.

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TUPAF088

Final factory-side Measurements of the Next SC CH-Cavities for the HELIAC-Project

cavity, resonance, heavy-ion, factory

943

M. Basten, M. Busch, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, F.D. Dziuba, M. Heilmann, S. Yaramyshev
GSI, Darmstadt, Germany

Funding: Work supported by the EU Framework Programme H2020 662186 (MYRTE); Work supported by BMBF Contr. No. 05P15RFBA;
The upcoming FAIR project (Facility for Antiproton and Ion Research) at GSI will use the existing UNILAC (UNIversal Linear Accelerator) as an injector to provide high intensity heavy ion beams at low repetition rates. As a consequence a new superconducting (sc) continous wave (cw) high intensity heavy ion Linac is required to provide ion beams above the coulomb barrier to keep the Super Heavy Element (SHE) physics program at GSI competitive on an international level. The fundamental Linac design comprises a high performance ion source, the High Charge State Injector (HLI) upgraded for cw-operation and a matching line (1.4 MeV/u) followed by a sc Drift Tube Linac (DTL). Four cryo modules each equipped with three Crossbar-H-mode (CH) structures provide for acceleration up to 7.3 MeV/u. The first section of this ambitious accelerator project has been successfully commissioned and tested with heavy ion beam from the HLI in 2017. It comprises two sc 9.3 T solenoids and a sc 217 MHz CH-cavity with 15 equidistant gaps as a demonstrator. The construction of the next two sc 217 MHz 8 gap CH-cavities is nearly finished and final factory-side measurements will be presented.

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TUPAF089

Initial Measurements on a New 10⁸ MHz 4-Rod CW RFQ Prototype for the HLI at GSI

rfq, simulation, dipole, resonance

946

D. Koser, K. Kümpel, H. Podlech
IAP, Frankfurt am Main, Germany
P. Gerhard
GSI, Darmstadt, Germany
O.K. Kester
TRIUMF, Vancouver, Canada

Funding: Work supported by BMBF Contr. No. 05P15RFBA and HIC for FAIR
The High Charge State Injector (HLI) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, is one of the two injector linacs for the Universal Linear Accelerator (UNILAC) and is also planned to serve as dedicated injector for a proposed superconducting CW linac for heavy element research. Within the scope of an intended CW upgrade of the HLI front end, a replacement for the existing 4-rod RFQ is desirable since its stable operation and performance is severely impeded by mechanical vibrations of the electrodes and a high thermal sensitivity*. With the aim of suppressing mechanical vibrations and providing efficient cooling considering high power CW operation, a completely new and improved 4-rod design was developed** with a focus on structural mechanical simulations using ANSYS. In order to validate the simulated RF performance, thermal behavior and structural mechanical characteristics, a 6-stem prototype was manufactured***. Initial low power RF measurements and basic piezo actuated mechanical investigations were done and the anticipated properties could be confirmed prior to planned high power RF tests and further mechanical vibration studies.
* D. Koser et al., THPIK021, Proc. of IPAC2017
** D. Koser et al., MOPOY020, Proc. of IPAC2016
*** D. Koser et al., TUPLR057, Proc. of LINAC2016

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TUPAK001

Progress of the Modulated 325 MHz Ladder RFQ

rfq, proton, quadrupole, operation

952

M. Schuett, U. Ratzinger, M. Syha
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P15RFRBA
Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.3 m Ladder-RFQ*. The unmodulated Ladder-RFQ features a very constant voltage along the axis. It accepted 3 times the operating power of which is needed in operation**. That level corresponds to a Kilpatrick factor of 3.1 with a pulse length of 200 μs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project. This particular high frequency creates difficulties for a 4-ROD type RFQ, which triggered the development of a Ladder RFQ with its high symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. The duty cycle is suitable up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in May 2018. We will show the latest results of manufacturing, beam dynamics simulations for the matching between LEBT and RFQ.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053

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TUPAK002

Advanced Approach for Beam Matching along the Multi-Cavity SC CW Linac at GSI

cavity, heavy-ion, emittance, proton

955

S. Yaramyshev, W.A. Barth, M. Heilmann
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
M. Basten, M. Busch, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

A multi-stage program for the development of a heavy ion superconducting (sc) continuous wave (cw) linac is in progress at HIM (Mainz, Germany) and GSI (Darmstadt, Germany) under support of IAP (Frankfurt, Germany). In 2017 the first section of the CW-Linac has been successfully commissioned at GSI. Beam acceleration at the CW-Linac is foreseen to be performed by up to twelve multi-gap CH cavities. The linac should provide the beam for physics experiments, smoothly varying the output particle energy from 3.5 to 7.3 MeV/u, simultaneously keeping high beam quality. Due to a wide variation of the input- and output -beam energy for each cavity, a longitudinal beam matching to every cavity is of high importance. An advanced algorithm for an optimization of matched beam parameters under variable rf-voltage and rf-phase of each cavity has been developed. The description of the method and the obtained results are presented in the paper.

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TUPAK003

Beam Dynamics Simulations for the New Superconducting CW Heavy Ion LINAC at GSI

cavity, heavy-ion, cryomodule, solenoid

959

M. Schwarz, M. Basten, M. Busch, H. Podlech
IAP, Frankfurt am Main, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany

Funding: Work supported by BMBF Contr. No. 05P15RFBA and EU Framework Programme H2020 662186 (MYRTE)
For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI/HIM and IAP is currently in progress. It aims for developing a supercon-ducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The LINAC design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with unchanged minimum energy spread. Testing of the first CH-cavity in 2016 demonstrated a promising maximum accelerating gradient of E_a = 9.6 MV/m; the worldwide first beam test with this sc multi-gap CH-cavity in 2017 was a milestone in the R&D work of GSI/HIM and IAP. In the light of experience gained in this research so far, the beam dynamics layout for the entire LINAC has recently been updated and optimized.

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TUPAK004

Superconducting CH-Cavity Heavy Ion Beam Testing at GSI

cavity, heavy-ion, acceleration, emittance

962

W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
M. Basten, M. Busch, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

Recently the first section of a standalone superconducting (sc) continuous wave (cw) heavy ion Linac as a demonstration of the capability of 217 MHz multi gap Crossbar H-mode structures (CH) has been commissioned and extensively tested with beam from the GSI- High Charge State Injector. The demonstrator set up reached acceleration of heavy ions up to the design beam energy and beyond. The required acceleration gain was achieved with heavy ion beams even above the design mass to charge ratio at high beam intensity and full beam transmission. This contribution presents systematic beam measurements with varying RF-amplitudes and phases of the CH-cavity, as well as versatile phase space measurements for heavy ion beams with different mass to charge ratio. The worldwide first and successful beam test with a superconducting multi gap CH-cavity is a milestone of the R&D work of Helmholtz Institute Mainz (HIM) and GSI in collaboration with Goethe University Frankfurt (GUF) in preparation of the sc cw heavy ion Linac project and other cw-ion beam applications.

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TUPAK008

Longitudinal Bunch Size Measurements with an RF Deflector at J-PARC LINAC

simulation, radio-frequency, rfq, DTL

974

M. Otani, K. Futatsukawa
KEK, Tsukuba, Japan
K. Hirano, A. Miura
JAEA/J-PARC, Tokai-mura, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Maruta
FRIB, East Lansing, USA

Measurement of the longitudinal bunch size is important for the stable beam operation. Especially in a medium energy beam transport (MEBT) located after a radio-frequency quadrupole in J-PARC, it is necessary to measure the bunch size with minimum set of equipment to avoid subsequent emittance growth due to space charge. We had proposed a longitudinal size measurement with an rf deflector normally used for deflecting theμbunch; phase spread is migrated to spatial one if the reference particle arrives at the deflector when the voltage is rising in time and is zero. Then a buncher cavity located upstream of the deflector is utilized to scan the phase spread to measure the longitudinal beam parameters. In this poster, recent measurement results are presented.

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TUPAK009

Muon Profile Measurement After Acceleration With a Radio-Frequency Quadrupole Linac

experiment, simulation, rfq, positron

977

M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, T. Yamazaki
KEK, Tsukuba, Japan
S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko
SNU, Seoul, Republic of Korea
K. Hasegawa, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
S. Li
The University of Tokyo, Graduate School of Science, Tokyo, Japan
G.P. Razuvaev
Budker INP & NSU, Novosibirsk, Russia
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
E. Won
Korea University, Seoul, Republic of Korea

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
The E34 experiment aims to measure muon anomalous magnetic moment with a precision of 0.1ppm. The experiment utilizes low emittance muon beam with a muon linac to sweep out beam related uncertainties, which limit the g-2 precision in past experiments. A beam matching with precise beam measurements is required to avoid substantial emittance growth and satisfy the experimental requirement on the beam emittance of around 1.5 pi mm mrad. We conduct profile measurement of muon after acceleration with a radio-frequency quadrupole (RFQ) on December 2017 following a first muon acceleration experiment on October. In the experiment of profile measurement, epi-thermal negative muonium ions are generated by injecting surface muons to a thin metal foil. The muonium ions are accelerated to 5 keV. by an electro-static lens and accelerated to 90 keV by the RFQ. Then the muonium ions are transported to a profile detector consisting of a micro-channel plate and a ccd camera via a quadrupole pair and a bending magnet. In this poster, the experimental result and comparison to the simulation are reported.

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TUPAK015

The SARAF-LINAC Project 2018 Status

cryomodule, cavity, status, controls

994

N. Pichoff, D. Chirpaz-Cerbat, R. Cubizolles, J. Dumas, R.D. Duperrier, G. Ferrand, B. Gastineau, P. Gastinel, F. Gougnaud, M. Jacquemet, C. Madec, Th. Plaisant, F. Senée, A. Sutra-Fourcade, D. Uriot
IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France
D. Berkovits, J. Luner, A. Perry, E. Reinfeld, J. Rodnizki
Soreq NRC, Yavne, Israel
M. Di Giacomo
GANIL, Caen, France

SNRC and CEA collaborate to the upgrade of the SARAF accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). CEA is in charge of the design, construction and commissioning of the MEBT line and the superconducting linac (SARAF-LINAC Project). The prototypes of the 176 MHz NC rebuncher, SC cavities, RF coupler and SC Solenoid-Package are under construction and their test stands construction or adaptation is in progress at Saclay. Meanwhile, the cryomodules and the global system just passed their Critical Design Reviews. This paper presents the status of the SARAF-LINAC Project at April 2018.

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TUPAL003

Measurement of the Injection Beam Parameters by the Multi-Wire Scanner for CSNS

injection, proton, MMI, neutron

1014

M.Y. Huang, H.C. Liu, S. Wang, Zh.H. Xu, P. Zhu
IHEP, Beijing, People's Republic of China
X.H. Lu
CSNS, Guangdong Province, People's Republic of China

In order to inject the H⁻ beam to the Rapid Cycling Synchrotron (RCS) with high precision and high transport efficiency, the injection beam parameters need to be measured and then corrected while its eccentric position or direction angle is too large. In this paper, firstly, a method to measure the injection beam parameters by using two of the four multi-wire scanners (MWSs) is presented. The injection commissioning results confirmed that this method works well. Secondly, a method to measure the signals of injection beam and circular beam by the INMWS02 is presented and the method work well during the beam commissioning.

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TUPAL012

Design and Fabrication of Hybrid RFQ Prototype

DTL, rfq, cavity, site

1032

P.Y. Yu, Y. He, C.X. Li, G.Z. Sun, F.F. Wang, Z.J. Wang, B. Zhang, T.M. Zhu
IMP/CAS, Lanzhou, People's Republic of China

Hybrid RFQ is proposed as a potential good choice at the low-energy range of linear accelerator. The complexi-ty of mechanical design and difficulty of fabrication are part of reasons impeding application of it and similar structures. In order to explore the practicable structure and research on RF parameters of this accelerating struc-ture, an aluminium prototype is developed.

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TUPAL017

Performance and Status of the J-PARC Accelerators

operation, target, ion-source, status

1038

K. Hasegawa, N. Hayashi, M. Kinsho, H. Oguri, K. Yamamoto, Y. Yamazaki
JAEA/J-PARC, Tokai-mura, Japan
T. Koseki, F. Naito, M. Yoshii
KEK, Tokai, Ibaraki, Japan
N. Yamamoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). Regarding 3 GeV beam from the RCS, we delivered it at 150 kW to the materials and life science experimental facility (MLF), for the neutron and muon users. The beam powers for the neutrino experiment at 30 GeV was 420 kW in May 2016, but increased to 470 kW in February 2017 thanks to the change and optimization of operation parameters. For the hadron experimental facility which uses a slow beam extraction mode at 30 GeV, we delivered beam at a power of 37 kW, after the recovery from a trouble at an electro static septum. We have experienced many failures and troubles to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented.

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TUPAL022

Low-Reflection RF Window for ACS Cavity in J-PARC Linac

cavity, Windows, proton, impedance

1051

J. Tamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
H. Ao
FRIB, East Lansing, USA
F. Naito, M. Otani
KEK, Tokai, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In the Japan Proton Accelerator Research Complex (J-PARC) linac, the Annular-ring Coupled Structure (ACS) cavities have been stably operating. To maintain this operation availability, we manufactured three backups of the pillbox-type RF windows for the ACS cavities in fiscal year 2015 and 2017. It is desirable to minimize the RF reflection of the RF window to prevent standing waves from exciting between the cavity and the RF window, and not to significantly change the optimized coupling factor between the cavity and the waveguide. To realize the minimization, the relative permittivities of the ceramic disks of the RF windows were evaluated by measuring the resonant frequencies of the pillbox cavity containing the ceramic disk. On the basis of the evaluated relative permittivities, the pillbox-part lengths of the RF windows were determined. The measured Voltage Standing Wave Ratios (VSWRs) of the manufactured RF windows are just about 1.08 and these are applicable for the practical use.

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TUPAL031

Errors Study of a Double-Pass Recirculating Superconducting Proton Linac

proton, cavity, emittance, quadrupole

1069

Y. Tao, K. Hwang, J. Qiang
LBNL, Berkeley, California, USA

The concept of recirculating superconducting proton linac was recently proposed. Beam dynamics simulations were carried out in a double-pass recirculating proton linac using a single bunch. Although all the beam line elements should be installed following the designed values, in reality, there exist machine imperfections that will cause beam off-centering and even particle losses. In this paper, we report on the study of the static and dynamic errors from RF cavities and magnetic focusing elements in the double-pass recirculating proton linac.

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TUPAL032

A Variable Field Phase-Shifter for Recirculating Proton Linacs

cavity, dipole, proton, superconducting-cavity

1072

Y. Tao, J. Qiang
LBNL, Berkeley, California, USA

The recirculating superconducting proton linac that has a potential to substantially save accelerator cost was re-cently proposed. It consists of three sections to accelerate the continues-wave (CW) beam to multiple GeVs. In the first section, the beam passes the linac two times. In the second and third sections, the beam goes through the linac four and six times. A phase-shifter is needed to meet the synchronous acceleration condition for multi-pass accel-eration using the same RF cavity due to the phase slip-page of the proton beam. Here we present the design of a variable field rectangular bend phase-shifter in which the beam goes to a different path in each pass inside the mag-net to meet the synchronous condition.

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TUPAL033

Time-of-Flight, Beam-Energy Measurement of the LANSCE 805-MHz Linac

proton, pick-up, controls, DTL

1075

Y.K. Batygin, F.E. Shelley, H.A. Watkins
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
Control of the beam-energy ramp along the length of a proton linear accelerator is required to keep the accelerator tuned according to design. Historically, the values of the field amplitudes and phases of the side-coupled, 805-MHz LANSCE linac modules are maintained using a well-known delta-t tuning procedure*. Time-of-flight measurements of the proton beam energy are now also being used to confirm and improve the overall control of the energy ramp along the linac. The time-of-flight method uses measurements of the difference in RF phases measured as the beam passes installed delta-t pickup loops. A newly developed chassis to control the 3D position of the beam centroid is used. Details of the procedure and results of measurements are presented.
* K.R.Crandall, "The Delta-T Tuneup Procedure for the LAMPF 805-MHz Linac", LANL Report LA-6374-MS, June 1976.

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TUPAL034

Effect of 805-MHz Linac RF Stability on Beam Losses in LANSCE High-Energy Beamlines

beam-losses, neutron, proton, operation

1078

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
Operation of an accelerator facility critically depends on stability of the field amplitudes and phases of the accelerating cavities. The LANSCE linear accelerator consists of a 201.25-MHz, drift-tube linac and an 805-MHz, side-coupled-cavity linac (SCL). Beam losses in the high-energy beamlines of the 800-MeV facility were measured versus variation of the amplitudes and phases of the 805-MHz, SCL, RF cavities. A recent study* confirms that to achieve low losses, the stability of the amplitudes and phases should be kept within 0.1% and 0.1o, respectively. This agrees with a previous study of beam losses in the 201.25-MHz linac. Details of the measurements and results are presented.
*L.J.Rybarcyk, R.C.McCrady, Proceeding of LINAC2016, East Lansing, MI, USA, MOPLR072, p.301.

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TUPAL037

Installation Progress on FRIB β=0.041 Cryomodules Toward Beam Commissioning

MMI, cryomodule, diagnostics, cryogenics

1087

H. Ao, B. Bird, N.K. Bultman, F. Casagrande, C. Compton, K.D. Davidson, K. Elliott, V. Ganni, A. Ganshyn, P.E. Gibson, I. Grender, W. Hartung, L. Hodges, K. Holland, A. Hussain, M. Ikegami, S. Jones, P. Knudsen, S.M. Lidia, I.M. Malloch, E.S. Metzgar, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, T. Russo, K. Saito, M. Shuptar, S. Stanley, S. Stark, D.R. Victory, J. Wei, J.D. Wenstrom, M. Xu, T. Xu, Y. Xu, Y. Yamazaki, Q. Zhao, S. Zhao
FRIB, East Lansing, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
R.E. Laxdal
TRIUMF, Vancouver, Canada
M. Wiseman
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) driver linac is to accelerate all the stable ion beams from proton to uranium beyond 200 MeV/u with beam powers up to 400 kW, which will be the first large-scale, CW SRF ion linac. The beam commissioning of the front end (from the ion source to the RFQ) already began and is in progress. The Accelerator Readiness Review (ARR) for beam through the first three β=0.041 cryomodules is scheduled for May 2018. The next step is the beam commissioning through the 12 SRF cavities housed in these 3 cryomodules with 6 superconducting solenoid magnets. The cryomodules and the adjacent warm diagnostics boxes in between have been already installed and aligned in the tunnel. This paper describes the installation progress of the β=0.041 cryomodules and plans for ARR02.

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TUPAL046

Construction, Test, and Operation of a new RFQ at the Spallation Neutron Source (SNS)

rfq, operation, ion-source, vacuum

1113

Y.W. Kang, A.V. Aleksandrov, W.E. Barnett, M.S. Champion, M.T. Crofford, B. Han, S.W. Lee, J. Moss, R.T. Roseberry, J.P. Schubert, A.P. Shishlo, M.P. Stockli, C.M. Stone, R.F. Welton, D.C. Williams, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters, J. Price
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: * This work was supported by SNS through UT-Battelle, LLC, under contract DEAC0500OR22725 for the U.S. DOE.
A new RFQ was successfully installed recently in the SNS linac to replace the old RFQ that was used for more than a decade with certain operational limitations. The new RFQ was completely tested with H⁻ ion source in the Beam Test Facility (BTF) at SNS. For robust operation of SNS at 1.4 MW, the full design beam power and to satisfy the beam current requirement of the forthcoming SNS proton power upgrade (PPU) project, an RFQ with enhanced performance and reliability was needed. The new RFQ was built to have the beam parameters identical to those of the first RFQ but with improved RF and mechanical stability and reliability for continuous operation of neutron production. The tests confirmed that the new RFQ can run with high beam transmission efficiency at around 90 % and notably improved operational stability. In this paper, construction, test, installation, and operation of the new RFQ in SNS are discussed with the performance improvements.

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TUPAL049

SNS Proton Power Upgrade Status

scattering, proton, cavity, injection

1120

M.A. Plum, G. A. Bloom, M.S. Champion, J. Galambos, M.P. Howell, S.-H. Kim, J. Moss, B.W. Riemer, K.S. White
ORNL, Oak Ridge, Tennessee, USA
R.B. Saethre, R. W. Steffey
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. This research was supported by the DOE Office of Science, Basic Energy Science, Scientific User Facilities.
The Spallation Neutron Source (SNS) Proton Power Upgrade (PPU) project aims to double the proton accelerator beam power from 1.4 to 2.8 MW. Over the past year PPU has completed the reviews necessary for Critical Decision-1 approval. The baseline design choices are being refined, and a cost-effective approach has been identified. The beam energy will be increased by 30% and the beam current capability improved by ~50%. The sub-system improvements and anticipated schedule will be discussed.

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TUPAL051

Program for High-Intensity RFQ Design With Matched and Equipartitioned Design Strategy

rfq, emittance, ISOL, resonance

1126

H.P. Li, M.J. Easton, Q. Fu, P.P. Gan, Y.R. Lu, Q.Y. Tan, Z. Wang, K. Zhu
PKU, Beijing, People's Republic of China

The deuteron driver accelerator of the Beijing Iso-tope Separation On-Line (BISOL) facility will acceler-ate and deliver a 20 mA deuteron beam to the targets with an energy of 40 MeV. As the injector of the driver linac, an RFQ is required to bunch and accelerate the 20 mA deuteron beam to 3 MeV with very high beam quality. In order to fulfil these requirements and re-duce time spent on optimization, an RFQ design pro-gram named RFQEP has been developed to generate the input file for the PARMTEQM code. In this program, the ‘matched and equipartitioned' design strategy is adopted to prevent halo formation and to avoid struc-ture resonances in high intensity RFQs. The detailed design aspects are studied in this paper and simulation results are given for an RFQ designed by this code, which shows the accuracy and the merits of the new program.

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TUPAL052

Multi-Physics Analysis of a CW IH-DTL for CIFNEF

DTL, cavity, neutron, operation

1129

Q.Y. Tan, M.J. Easton, Q. Fu, P.P. Gan, H.P. Li, Y.R. Lu, Z. Wang
PKU, Beijing, People's Republic of China

The Compact Intense Fast NEutron Facility (CIFNEF) project aims to produce high intense neutrons via the 7Li (d, n) 8Be reaction using a 5 MeV, 10 mA deuteron linac. The main components of the linac are an ion source, a short radio frequency quadrupole (RFQ) and an interdigi-tal H-mode drift tube linac (IH-DTL). The IH-DTL will accelerate the continuous wave (CW) deuteron beam from 1 MeV to 5 MeV with a total cavity length of 1.25 m using Kombinierte Null Grad Struktur (KONUS) design, achieving an accelerating gradient of 3.2 MV/m. The RF power loss for the whole cavity is estimated to be 85 kW. This high power loss is a significant challenge to the cooling design, as it could cause large rises in tempera-ture, thermal deformation and frequency drift. A detailed multi-physics analysis of the CW IH-DTL is presented in this paper.

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TUPAL073

Conceptual Design of a Drift Tube LINAC for Proton Therapy

DTL, emittance, proton, rfq

1182

P.F. Ma, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, X.D. Yu, S.X. Zheng
TUB, Beijing, People's Republic of China
Y.H. Pu, J. Qiao, C.P. Wang, X.C. Xie, F. Yang
Shanghai APACTRON Particle Equipment Company Limited, Shanghai, People's Republic of China

Funding: National Key Research and Development Program of China (grant number 2016YFC0105408)
The conceptual design of an Alvarez-type Drift Tube Linac for one proton therapy facility is described in this paper. The design optimization of the Drift Tube Linac is carried out in the principle of adopting domestic mature technologies and cost control. The error study of the Drift Tube Linac is also given in this paper.

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TUPAL075

Mechanical Design and Error Analysis of a 325 MHz IH-DTL Test Cavity

DTL, alignment, cavity, simulation

1186

R. Tang, C.T. Du, X. Guan, K.D. Man, C.-X. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People's Republic of China
J. Li
NUCTECH, Beijing, People's Republic of China

A 325 MHz interdigital H-mode drift tube linac (IH-DTL) test cavity with a modified KONUS beam dynamics is under fabrication at Tsinghua University. The inner diameter of the tank increases from 196.8 to 232.6 mm. The mechanical design is considered carefully because of its small geometry. A three-piece design has been adopted in the mechanical design. The error analysis is carried out to determine the error requirement of machining and alignment. The details of mechanical design and error analysis is presented.

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TUPAL077

2D-3D PIC Code Benchmarking/Anchoring Comparisons For a Novel RFQ/RFI LINAC Design

rfq, space-charge, simulation, experiment

1194

S.J. Smith, S. Biedron, A. M. N. Elfrgani, E. Schamiloglu
University of New Mexico, Albuquerque, USA
M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson
Ion Linac Systems, Inc., Albuquerque, USA
K. Kaneta
CICS, Tokyo, Japan

Funding: *The study at the University of New Mexico was supported in part by DARPA Grant N66001-16-1-4042 and gift to the University of New Mexico Foundation by ILS.
In this study, comparisons are made between several particle dynamics codes (namely CST Particle Studio, GPT, and upgraded PARMILA codes) in order to benchmark them. The structure used for the simulations is a novel 200 MHz, 2.5 MeV, CW RFQ/RFI LINAC designed by Ion Linac Systems (ILS). The structure design and parameters are provided, simulation techniques are explained, and results from all three code families are presented. These results are then compared with each other, identifying similarities and differences. Numerous parameters for comparison are used, including the transmission efficiency, Q-factor, E-field on axis, and beam properties. Preliminary anchoring between modeling and simulation performance predictions and experimental measurements will be provided.

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TUZGBF5

KlyLac Prototyping for Borehole Logging

klystron, cavity, feedback, simulation

1244

A.V. Smirnov, R.B. Agustsson, M.A. Harrison, A.Y. Murokh, A.Yu. Smirnov
RadiaBeam Systems, Santa Monica, California, USA
S. Boucher, T.J. Campese, K.J. Hoyt
RadiaBeam, Los Angeles, California, USA
E.A. Savin
MEPhI, Moscow, Russia
A.A. Zavadtsev
Nano, Moscow, Russia

Funding: Work supported by the U.S. Department of Energy (award No. DE-SC0015721)
Linac-based system for borehole logging exploits KlyLac approach combing klystron and linac sharing the same electron beam, vacuum volume, and RF network enabling self-oscillation due to a positive feedback. The KlyLac prototype design tailors delivering ~1 MeV electrons in a linac section using part of the beam injected from a sheet beam klystron (SBK). The linac part is based on a very robust, high group velocity, cm-wave, and a standing wave accelerating structure of a 'cross-pin' type supplied by a sampler. The SBK part features a permanent magnet solenoid focusing, relatively low voltage, and high aspect ratio beam. The main SBK characteristics (perveance, power, and efficiency) are expected to be similar to that for a magnetron.

Slides TUZGBF5 [3.280 MB]

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TUPMF024

Validation of the Halbach FFAG Cell of Cornell-BNL Energy Recovery Linac

permanent-magnet, quadrupole, collider, focusing

1304

F. Méot, S.J. Brooks, 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 optical properties of the Halbach technology based CBETA ERL return FFAG arc cell are investigated, using its 3-D OPERA field map model. This includes paraxial and large amplitude motion, tune path, study of resonances, dynamic acceptance, effects of various defects, 300-cell 10k-particle bunches 6D transmission trials. These investigations, a 2~3 year investment, have validated the Halbach technology in the linear FFAG cell application, from the point of view of the beam dynamics, so supporting its approval as the required technology for CBETA, in December 2016.

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TUPMF036

Top Off of NSLS-II with Inefficient Injector

booster, injection, storage-ring, operation

1327

R.P. Fliller, A.A. Derbenev, V.V. Smaluk, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The NSLS-II is a 3 GeV storage with a full energy injector capable of top off injection. The injector consists of a 200 MeV linac injecting a 3 GeV booster. Recent operational events have caused us to investigate 100 MeV injection into the booster. As the booster was not designed for injection at this low energy, beam loss is observed with this low energy booster injection. This beam loss not only results of overall charge loss from the train, but a change in the overall charge distribution in the bunch train. In this paper we discuss the performance of injecting into the storage ring with the inefficient charge transfer through the injector. The changes to the top off method are discussed, as well as the achieved storage ring current stability and fill pattern.

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TUPMF037

Development of New Operational Mode for NSLS-II Injector: Low Energy 100MeV Linac-to-Booster Injection

booster, injection, operation, klystron

1330

X. Yang, A.A. Derbenev, R.P. Fliller, T.V. Shaftan, V.V. Smaluk
BNL, Upton, Long Island, New York, USA

The NSLS-II injector consists of a 200 MeV linac and a 3 GeV full-energy booster synchrotron. The linac contains five traveling-wave S-band accelerating structures driven by two high-power klystrons, with a third klystron as spare. In the event that the spare klystron is not available, the failure of one klystron will prohibit the linac from injecting into the booster as the energy is too low. Therefore, we wish to develop a new operational mode that the NSLS-II injector can operate with a single klystron providing 100 MeV beam from the linac. A decremented approach with intermediate energies 170 MeV, 150 MeV, etc., takes advantages of pre-calculated booster ramps and beam based online optimization. By lowering the booster injection energy in a small step and online optimizing at each step, we were able to achieve 100 MeV booster injection. 170 MeV operation mode of the NSLS-II injector has been implemented since May 31, 2017, with a similar overall performance compared to the standard 200 MeV operation but fewer klystron trips. 100 MeV single-klystron operation has been successfully demonstrated with 20-30% overall efficiency, which is limited by booster acceptance.

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TUPMF058

Conceptual Design of HEPS Injector

booster, storage-ring, injection, dipole

1394

J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou
IHEP, Beijing, People's Republic of China

Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.

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TUPMF060

Design of Bunch Lengthening System in Electron Linac

booster, photon, lattice, bunching

1401

C. Meng, Y. Jiao, J.L. Li, S. Pei, Y.M. Peng, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, ultralow-emittance light source to be built in China. The injector is composed of a linac and a full energy booster. To increase the threshold of TMCI in the booster, the HEPS linac design has been evolved with several iterations. The important middle-version design is a 300 MeV linac with rms bunch length larger than 20 ps. One bunch lengthening system is proposed and discussed in this paper.

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TUPMF061

Physical Design of the 500 MeV Electron Linac for the High Energy Photon Source

electron, gun, bunching, emittance

1404

S. Pei, D.Y. He, X. He, J.L. Li, J. Liu, X. Ma, C. Meng, X. Wang, O. Xiao, J.R. Zhang, Z.S. Zhou
IHEP, Beijing, People's Republic of China
S. Shu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

Funding: Work supported by the HEPS project and the National Natural Science Foundation of China (11475201). peisl@ihep.ac.cn
The High Energy Photon Source (HEPS) is a 6 GeV light source with ultra-low emittance, it is proposed to be built at Huairou district, northeast suburb of Beijing, China. A 500 MeV electron linac will be used to generate the electron beam for injection into the booster. Here the preliminary physical design of the electron linac is presented.

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TUPMF063

The Considerations of Improving TMCI Threshhold on HEPS Booster

booster, lattice, storage-ring, injection

1411

Y.M. Peng, J.L. Li, C. Meng, S. Pei, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is proposed in Beijing, China. The on-axis swap-out injection scheme will be used in the storage ring mainly because of the small dynamic aperture. Therefore, the booster needs to store more than 2.5 nC bunch charge. Under this requirement, the transverse mode coupling instability (TMCI) at the injection energy becomes the bunch charge restriction in the booster. Several changes in booster and linac for improving bunch charge threshold limited by TMCI are considered. The details will be expressed in this paper.

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TUPMF081

Microphonic Detuning Induced Coupler Kick Variation at LCLS-II

cavity, laser, free-electron-laser, beam-loading

1456

T. Hellert
DESY, Hamburg, Germany
W. Ackermann, H. De Gersem
TEMF, TU Darmstadt, Darmstadt, Germany
C. Adolphsen, Z. Li, C.E. Mayes
SLAC, Menlo Park, California, USA

The LCLS-II free-electron laser will be an upgrade of the existing Linac Coherent Light Source (LCLS), including a 4 GeV CW superconducting linac based on the TESLA technology. The high quality factor of the cavity makes it very sensitive to vibrations. The shift of its eigenfrequency (i.e., detuning) will be compensated by the power source in order to assure a constant accelerating voltage. Significant variations of the forward power are expected which result in coupler kick variations induced by the fundamental power coupler. In this work we estimate the magnitude of trajectory jitter caused by these variations. High precision 3D field maps including standing and traveling-wave components for a cavity with the LCLS-II coupler design are presented.

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TUPMF086

Status of the ARES RF Gun at SINBAD: From its Characterization and Installation towards Commissioning

gun, cavity, status, electron

1474

B. Marchetti, R.W. Aßmann, S. Baark, F. Burkart, U. Dorda, K. Flöttmann, I. Hartl, J. Hauser, J. Herrmann, M. Hüning, K. Knebel, O. Krebs, G. Kube, W. Kuropka, S. Lederer, F. Lemery, F. Ludwig, D. Marx, F. Mayet, M. Pelzer, I. Peperkorn, F. Poblotzki, S. Pumpe, J. Rothenburg, H. Schlarb, M. Titberidze, G. Vashchenko, T. Vinatier, P.A. Walker, L. Winkelmann, K. Wittenburg, S. Yamin, J. Zhu
DESY, Hamburg, Germany

The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) is foreseen to host multiple experiments relating to the production of ultra-short electron bunches and novel high gradient acceleration techniques. The SINBAD-ARES linac will be a conventional S-band linear RF accelerator allowing the production of low charge (0.5 pC - tens pC) ultra-short electron bunches (FWHM length =< 1 fs - few fs) with 100 MeV energy. The installation of the linac will proceed in stages. In this paper we report on the status of the characterization of the ARES RF gun and the installations of the related infrastructure.

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TUPMK008

Highly-stable, High-power Picosecond Laser Optically Synchronized to a UV Photocathode Laser for an ICS Hard X-ray Generation

laser, timing, cathode, electron

1504

K.-H. Hong
MIT, Cambridge, Massachusetts, USA
D. Gadonas, L.M. Hand, K. Neimontas, A. Senin, V. Sinkevicius
Light Conversion, Vilnius, Lithuania
W.S. Graves, M.R. Holl, L.E. Malin, C. Zhang
Arizona State University, Tempe, USA
S. Klingebiel, T. Metzger, K. Michel
TRUMPF Scientific Lasers GmbH + Co. KG, Munchen-Unterfoehring, Germany

Under the CXLS project at Arizona State University we are developing an inverse Compton scattering (ICS) hard X-ray source* towards a compact XFEL with electron nano-bunching. The ICS interaction is critically dependent on the quality of driver pulses such as: 1) available peak intensity, 2) energy/pointing stability, and 3) relative timing stability to UV pulses initially triggering electron beams. Here, we report on a highly stable, 1 kHz, 200 mJ, 1.1 ps, 1030 nm laser with good beam quality as an ICS driver, optically synchronized to a UV photocathode laser. The ICS driver is based on a Yb:YAG thin-disk regenerative amplifier (RGA), ensuring an excellent energy stability (shot-to-shot 0.52% rms; 0.14% rms over 24 hours). The pointing stability better than 4 urad is obtained. The M2 factor is as good as ~1.5 at the full energy, leading to the achievable laser intensity of >10¹⁷ W/cm² with f/10 focusing. The photocathode laser, a frequency-quadrupled Yb:KGW RGA, share a common seed oscillator with the ICS driver for optical synchronization. The residual sub-ps timing drift is further reduced to 33 fs rms using an optical locking scheme based on a parametric amplifier.
* W.S. Graves et al., "Compact X-ray source based on burst mode inverse compton scattering at 100 kHz," Phys. Rev. ST Accel. Beams, Vol. 17, p. 120701 (Dec. 2014).

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TUPML003

Design of an L-band Accelerating Structure for the Argonne Wakefield Accelerator Facility Witness Beam Line Energy Upgrade

impedance, coupling, acceleration, quadrupole

1533

J.H. Shao, M.E. Conde, D.S. Doran, J.F. Power
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

The Argonne Wakefield Accelerator (AWA) facility has been devoting much effort to the fundamental R&D of two-beam acceleration (TBA) technology with two parallel L-band beam lines. Beginning from the 70 MeV drive beam line, the high frequency (C-band and above) rf power is extracted from the beam by a decelerating structure (a.k.a. power extractor), transferred to an accelerating structure in the witness beam line, and used to accelerate the 15 MeV main beam. These high frequency accelerating structures usually have a small aperture to obtain high gradient and high efficiency, making it difficult for the low energy main beam to pass. To address this issue, one proposal is to increase the main beam energy to above 30 MeV by replacing the current witness linac. A 9-cell 𝜋-mode L-band standing-wave accelerating structure has therefore been designed to meet the high shunt impedance and low cost requirements. In addition, the single-feed coupling cell has been optimized with additional symmetrical ports to eliminate field distortion. The detailed design of the new accelerating structure will be presented in this paper.

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TUPML004

Correction of Emittance Growth Due to Quad Components in Solenoids With Quad Correctors at AWA

emittance, solenoid, simulation, electron

1536

L.M. Zheng, C.-X. Tang
TUB, Beijing, People's Republic of China
M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA

An asymmetrical electron beam is observed on the drive beamline at Argonne Wakefield Accelerator (AWA) due to the quad components in the solenoids. An ASTRA simulation shows that the emittance will increase when the electron beam passes through solenoids with quad errors. We use two quad correctors to correct this emittance growth. A preliminary emittance correction result is presented in this paper.

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TUPML016

High-Intensity Magnetron H⁻ Ion Sources and Injector Development at BNL Linac

operation, rfq, ion-source, injection

1564

A. Zelenski, G. Atoian, T. Lehn, D. Raparia, J. Ritter
BNL, Upton, Long Island, New York, USA

The BNL magnetron-type H⁻ ion source and the injec-tor are being upgraded to higher duty-factor as a part of Linac intensity increase project [1]. The BNL magnetron source presently delivers 110 -120 mA H⁻ ion current with 650 us pulse duration and 7 Hz repetition rate. The pulse duration was increased to 1000 μs by modifications of the gas injector pulsed valve and the use of the new arc-discharge power supply (with the arc-current stabilization circuit) which improved current stability and reduced current noise. The Low Energy Beam Transport (LEBT) lines combine two beams. The first line is the polarized OPPIS (Optically Pumped Polarized H⁻ Ion Source) beam-line and the second is the high-intensity un-polarized beam-line from the magnetron source, which transports beam to the RFQ after the passage of 45 degree bending magnet. The second magnetron source was installed in the straight LEBT section in 2017, in which the polarized OPPIS beam was not planned. In this, optimal for H⁻ beam transport configuration, the beam intensity was increased to 80 mA after the RFQ. The experience of the two sources layout operation (one source in operation the second source in standby) might be useful for facilities with the high downtime cost (like high-energy collider LHC or multi-user facilities like SNS).

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TUPML045

Segmented Terahertz Driven Device for Electron Acceleration

electron, acceleration, laser, controls

1642

D. Zhang
DESY, Hamburg, Germany
A-L. Calendron, H. Cankaya, M. Fakhari, A. Fallahi, Y. Hua, N.H. Matlis, X. Wu, L.E. Zapata
CFEL, Hamburg, Germany
M. Hemmer, F.X. Kärtner
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
F.X. Kärtner
MIT, Cambridge, Massachusetts, USA

Funding: ERC Synergy Grant AXSIS (609920), Deutsche Forschungsgemeinschaft (SPP1840 SOLSTICE and CUI EXC1074), and Gordon and Betty Moore foundation (ACHIP GBMF4744)
We present a segmented THz based device (STEAM) capable of performing multiple high-field operations on the 6D-phase-space of ultrashort electron bunches. Using only a few microjoules of single-cycle THz radiation, we have shown record THz-based acceleration of >30 keV of an incoming 55keV electron beam, with a peak acceleration field gradient of around 70 MV/m that is comparable with that from a conventional RF accelerator. It can be scaled up to GV/m gradients that can accelerate electrons into the MeV regime. At the same time, the STEAM device can also manipulate the electrons that show high focusing gradient (2 kT/m), compression of electron bunches down to 100 fs and streaking gradient of 140 μrad/fs, which offers temporal profile characterizations with resolution below 10 fs. The STEAM device can be fabricated with regular mechanical machining tools and supports real-time switching between different modes of operation. It paves the way for the development of THz-based compact electron guns, accelerators, ultrafast electron diffractometers and Free-Electron Lasers.

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TUPML068

The European Spallation Source Neutrino Super Beam Design Study

proton, detector, target, neutron

1702

M. Dracos
IPHC, Strasbourg Cedex 2, France

Funding: This project is now supported by the COST Action CA15139/EuroNuNet and EU/H2020 innovation programme ESSnuSB under grant agreement No 777419.
ESSnuSB proposes to use the proton linac of the European Spallation Source (ESS) currently in construction in Lund (Sweden) to produce a very intense neutrino super beam, in parallel with the spallation neutron production. The ESS linac is expected to be operational by 2023 delivering 5 MW average power, 2 GeV proton beam, with 2.86 ms long pulses at a rate of 14 Hz. The primary proton beam-line completing the linac will consist of an accumulator ring to compress the beam pulses to 1.3 μs and a switchyard to distribute the protons onto the target station. The secondary beam-line producing neutrinos will consist of a four-horn/target station, a decay tunnel and a beam dump. A megaton scale water Cherenkov detector will be located at a baseline of about 500 km in one of the existing mines in Sweden and it will measure the neutrino oscillations. ESSnuSB was recently granted by the European H2020-INFRADEV program to start beginning of 2018 a 4-year design study on the feasibility of such facility. This paper presents the objectives, the steps and the organization of the ESSnuSB DS.

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TUPML071

Experimental Performance of the Chopper for the ESS Linac

electron, high-voltage, experiment, proton

1709

G. Torrisi, L. Allegra, A.C. Caruso, G. Castro, L. Celona, G. Gallo, S. Gammino, O. Leonardi, A. Longhitano, D. Mascali, L. Neri, S. Passarello, G. Sorbello
INFN/LNS, Catania, Italy

At the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) was completed in November 2017. The ESS requires a high intensity proton beam (74 mA pulsed at 14 Hz of repetition rate), with fast Beam pulse rise/fall time (< 20 μs). In order to meet the project requirement, an electrostatic chopping system has been used in the Low Energy Beam Transport (LEBT). The design of the control system was done also to be the main element of the fast beam abort system and taking into account the radiation issue in the accelerator tunnel. This paper describes the performances of the chopper. The experimentally-achieved rise/fall times of the beam pulses measured by using an AC Current Transformer (ACCT) at the end of the LEBT collimator, are presented. An experimental investigation of the effects of different amounts and types of gas injected into the LEBT (for the sake of space charge compensation) has been carried out with respect to the beam and chopper parameters.

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WEXGBF1

Testing of the ESS MB-IOT Prototypes

klystron, cavity, operation, electron

1759

M. Jensen
ESS, Lund, Sweden
C. Bel, A. Beunas, D. Bussiere, P. Cacheux, V. Hermann, J.C. Racamier, C. Robert
TED, Thonon, France
M. Boyle, H. Schult
L-3, Williamsport, Pennsylvania, USA
G. Cipolla, E. Montesinos, M.S.B. Sanchez Barrueta
CERN, Geneva 23, Switzerland
T. Kimura, P.E. Kolda, P. Krzeminski, L. Kurek, S. Lenci, O.S. Sablic, L. Turek, C. Yates
CPI, Palo Alto, California, USA
M.F. Kirshner
LANL, Los Alamos, New Mexico, USA
R.D. Kowalczyk, A.V. Sy, B.R. Weatherford
SLAC, Menlo Park, California, USA
A. Zubyk
L3 EDD, Williamsport, USA

ESS is considering the use of MB-IOTs for parts of the high-beta linac. Two prototypes have been built by indus-try, namely L3 and CPI/Thales and have passed the factory acceptance test with excellent results. Both tubes will go through further extensive testing at CERN for ESS follow-ing delivery and a final decision on tube technology will be taken in April 2018. This invited talk presents the back-ground for the technical decision of IOTs vs klystrons, associated impact for ESS, and latest plans for industrial production of these IOTs for ESS.

Slides WEXGBF1 [9.836 MB]

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WEXGBF3

RF System for FRIB Accelerator

controls, cavity, LLRF, rfq

1765

D.G. Morris, J. Brandon, N.K. Bultman, K.D. Davidson, A. Facco, P.E. Gibson, L. Hodges, M.G. Konrad, T.L. Larter, H. Maniar, P. Morrison, P.N. Ostroumov, J.T. Popielarski, G. Pozdeyev, H.T. Ren, T. Russo, K. Schrock, R. Walker, J. Wei, T. Xu, Y. Xu, S. Zhao
FRIB, East Lansing, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy

The RF system of the FRIB driver accelerator includes solid state amplifiers up to 18 kW operating at frequencies from 80.5 MHz to 322 MHz. Much higher power is required for the normal conducting RFQ, ~100 kW, and it is based on vacuum tubes. This invited talk presents the performance of solid state amplifiers and LLRF in off-line testing and on-line testing of the RFQ amplifier.

Slides WEXGBF3 [14.107 MB]

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WEYGBE2

Applications of Caustic Methods to Longitudinal Phase Space Manipulation

FEL, electron, optics, gun

1790

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
T.K. Charles
CERN, Geneva, Switzerland
D. Douglas
JLab, Newport News, Virginia, USA
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Longitudinal phase space management is a key feature of recirculating machines. Careful consideration of the longitudinal matching is required not only in order to ensure a high peak current, low energy spread bunch is delivered to the FEL but also to support the deceleration and energy recovery of the spent beam. In a similar manner, longitudinal phase space manipulation can be utilised for pulse shaping in bunch compression, to minimise the influence of CSR-induced emittance growth. In this paper, we present a method for longitudinal phase space matching based upon the avoidance of electron trajectory caustics. Through considering the conditions under which caustics will form, we generate exclusion plots identifying the viable parameter space at numerous positions through beam acceleration and energy recovery. The result is a method for selecting the linear momentum compaction and the higher-order momentum compaction to satisfy the non-caustic condition whilst achieving the bunch compression or lengthening as required.

Slides WEYGBE2 [6.292 MB]

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WEPAF006

Fast Photodetector Bunch Duration Monitor for the Advanced Photon Source Particle Accumulator Ring

detector, laser, synchrotron, photon

1819

J.C. Dooling, J.R. Calvey, K.C. Harkay, B.X. Yang, C. Yao
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A fast photodetector is used to monitor the bunch duration in the Advanced Photon Source (APS) Particle Accumulator Ring (PAR). The Bunch Duration Monitor (BDM) diagnostic provides an accurate measure of the PAR bunch length. PAR BDM data show good agreement with streak camera measurements. The BDM is based on the metal-semiconductor-metal (MSM) photodetector Hamamatsu G4176-03 MSM with specified rise and fall times of 30 ps. The BDM has sufficient frequency response to resolve the PAR bunch near extraction where, under low-charge conditions, minimum rms pulse durations of 200-300 ps are observed. Beam from the PAR is injected into the Booster; for efficient capture, injected rms bunch duration from the PAR must be less than 600 ps. The MSM detector exhibits a ringing response to fast input signals. To overcome this, the BDM output is de-convolved with the impulse response function of the detector-amplifier circuit. Turn-by-turn bunch duration data is presented versus charge and time in the PAR cycle. Charge calibration is used to determine fit parameters for bunch duration measurements in peak-detection mode. Observations relevant to APS Upgrade high-charge studies are presented.

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WEPAF022

Application of Machine Learning to Minimize Long Term Drifts in the NSLS-II Linac

klystron, network, operation, booster

1867

R.P. Fliller, C. Gardner, P. Marino, R.S. Rainer, M. Santana, G.J. Weiner, X. Yang, E. Zeitler
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
Machine Learning has proven itself as a useful technique in a variety of applications from image recognition to playing Go. Artificial Neural Networks have certain advantages when used as a feedforward system, such as the predicted correction relies on a model built from data. This allows for the Artificial Neural Network to compensate for effects that are difficult to model such as low level RF adjustments to compensate for long term drifts. The NSLS-II linac suffers from long terms drifts from a number of sources including thermal drifts and klystron gain variations. These drifts have an effect on the injection efficiency into the booster, and if left unchecked, portions of the bunch train may not be injected into the booster, and the storage ring bunch pattern will ultimately suffer. In this paper, we discuss the application of Artificial Neural Networks to compensate for long term drifts in the NSLS-II linear accelerator. The Artificial Neural Network is implemented in python allowing for rapid development of the network. We discuss the design and training of the network, along with results of using the network in operation.

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WEPAF066

The New CLIC Main Linac Installation and Alignment Strategy

alignment, target, quadrupole, collider

1979

H. Mainaud Durand, J. Gayde, J. Jaros, M. Sosin, A. P. Zemanek
CERN, Geneva, Switzerland
V. Rude
ESGT-CNAM, Le Mans, France

A complete solution has been proposed for the pre-alignment of the CLIC main linac in 2012 for the Conceptual Design Report. Two recent studies provide new perspectives for such a pre-alignment. First in a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale (PACMAN), new solutions to fiducialise and align different types of components within a micrometric accuracy on the same support were proposed and validated, using a stretched wire. Secondly, a 5 degree of freedom adjustment platform with plug-in motors showed a very accurate and efficient way to adjust remotely components. By combining the results of both studies, two scenarios of installation and alignment for the CLIC main linac are proposed, providing micrometric and automatized solutions of micrometric assembly, fiducialisation and alignment in metrological labs or in the tunnel. In this paper, the outcome of the two studies are presented; the two scenarios of installation and alignment are then detailed and discussed.

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WEPAF076

Availability Studies Comparing Drive Beam and Klystron Options for the Compact Linear Collider

klystron, operation, simulation, software

2013

O. Rey Orozko, S. Döbert, M. Jonker
CERN, Geneva, Switzerland

The initial proposal for the Compact Linear Collider (CLIC) is based on a two beam-scheme to accelerate the main colliding beams. For low collision energies, the main beam could also be accelerated by powering the accelerating structures with klystrons instead of the two-beam scheme. This paper studies the feasibility of this new alternative in terms of machine availability. An implemented bottom-up availability model considers the components failure modes to estimate the overall availability of the system. The model is defined within a Common Input Format scheme and the AvailSim3 software package is used for availability simulations. This paper gives an overview of the systems affecting the beam powering availability and makes recommendations for availability improvements.

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WEPAF077

Performance Evaluation of Linac4 During the Reliability Run

operation, MMI, proton, controls

2016

O. Rey Orozko, A. Apollonio, S.S. Erhard, G. Guidoboni, B. Mikulec, J.A. Uythoven
CERN, Geneva, Switzerland

Linac4 will replace Linac2 as the first element in the CERN proton injector chain from 2020 onwards, following the second LHC long shutdown (LS2). With more than three times higher energy and number of compo-nents than Linac2, beam availability is one of the main challenges of Linac4. Intended as a smooth transition from commissioning to operation, a Linac4 Reliability Run was started in July 2017 and is foreseen to last until mid-May 2018. The goal is to achieve the target availability of 95 %. This implies consolidated routine operation and identification of recurring problems. This paper introduces the schedule and operational aspects of the Linac4 Reliability Run, including the developed tools and methods for availability tracking. The paper also summarizes the lessons learned during the first period of the Linac4 Reliability Run with respect to fault tracking and provides an in-depth analysis of the failure modes and observed availability.

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WEPAF086

Latest Developments and Updates of the ESS Linac Simulator

DTL, cavity, solenoid, space-charge

2051

J.F. Esteban Müller, E. Laface
ESS, Lund, Sweden

A fast and accurate online model is required for optimal commissioning and reliable operation of the high-power proton linac at the European Spallation Source. The Open XAL framework, initially developed at SNS, is used at ESS for the development of high-level physics applications. The online model we use, known as ESS Linac Simulator (JELS), extends the Open XAL model with several features. This paper describes the latest updates carried out to JELS. Two new elements have been implemented: a solenoid field map for the LEBT and a DTL Tank element that automatically calculates each gap phase. All calculations are now done in the laboratory frame, in agreement with Open XAL convention. A thorough benchmark of the model against TraceWin, which is the tool used for the lattice design, is also presented.

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WEPAK006

Bunch Shape Measurements at the GSI CW-Linac Prototype

cavity, heavy-ion, bunching, emittance

2091

T. Sieber, W.A. Barth, P. Forck, V. Gettmann, M. Heilmann, H. Reeg, A. Reiter, S. Yaramyshev
GSI, Darmstadt, Germany
F.D. Dziuba, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
A. Feschenko, S.A. Gavrilov
RAS/INR, Moscow, Russia

The existing GSI accelerator will become the injector for FAIR. To preserve and enhance the current experimental program at UNILAC, a new Linac is under development, which shall run in parallel to the FAIR injector, providing cw-beams of ions at energies from 3.5 - 7.3 MeV/u. For this cw-Linac a superconducting prototype cavity has been developed and was first operated with beam in summer 2017. The resonator is a cross-bar H-structure (CH) of 0.7 m length, with a resonant frequency of 216.8 MHz. It has been installed behind the GSI High Charge State Injector (HLI), which provided 10⁸ MHz bunches of 1.4 MeV/u Ar⁶⁺/9+/11+ ions at a duty cycle of 25 %. Due to the frequency jump and small longitudinal acceptance of the CH, proper matching of the HLI beam to the prototype was required. The bunch properties of the injected beam as well as the effect of different phase- and amplitude-settings of the cavity were measured in detail with a bunch shape monitor (BSM) fabricated at INR, Moscow, while the mean energy was analyzed by time of flight method. In this contribution, the bunch shape measurements are described and the capabilities of the used BSM measurement principle are discussed.

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WEPAK016

RF Monitor System for SuperKEKB Injector Linac

FPGA, controls, data-acquisition, EPICS

2128

H. Katagiri, M. Akemoto, D.A. Arakawa, T. Matsumoto, T. Miura, F. Qiu, Y. Yano
KEK, Ibaraki, Japan

A new radio frequency (RF) monitor system for the SuperKEKB project has been developed at the KEK in-jector linac. The RF monitor unit, which consists of an analog I/Q demodulator, ADC/DAC board, and FPGA board achieved 50-Hz data acquisition and beam mode identification. On the RF monitor, the amplitude and phase measurement precision has achieved 0.1% rms and 0.1° rms, respectively. Sixty RF monitor units have been installed in the linac. The present status of the RF monitor system will be re-ported.

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WEPAK017

Low-level RF System for the SuperKEKB Injector LINAC

injection, booster, controls, positron

2131

T. Matsumoto, M. Akemoto, D.A. Arakawa, H. Katagiri, T. Miura, F. Qiu, Y. Yano
KEK, Ibaraki, Japan
M. Akemoto, T. Miura, F. Qiu
Sokendai, Ibaraki, Japan

The low-level RF (LLRF) system of the KEK injector linac has been upgraded for the SuperKEKB. As a major change, a low-emittance and high-current RF gun was installed to satisfy 40-times higher luminosity at the SuperKEKB. In order to balance the stable RF gun operation and the electron/positron beam acceleration, the phase shifter is developed and the configuration of main drive system in the LLRF system is modified. The present status and future plan of the LLRF system upgraded for the SuperKEKB will be reported.

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WEPAK018

LLRF Control Unit for SuperKEKB Injector Linac

controls, LLRF, klystron, timing

2134

T. Miura, M. Akemoto, D.A. Arakawa, H. Katagiri, T. Matsumoto, F. Qiu, Y. Yano
KEK, Ibaraki, Japan
N. Liu
Sokendai, Ibaraki, Japan

The low-level RF (LLRF) control unit based on the digital system has been developed for a stable and high precision pulse modulation for the SuperKEKB. The RF pulse is changed at a 50-Hz repetition rate for the top-up injection to four different rings by the event system. The LLRF control unit has not only the pulse modulator, but also other functions: VSWR meter, RF monitor, event receiver (EVR), and pulse-shortening detection.

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WEPAL001

LLRF Control and Master Oscillator System for Damping Ring at SuperKEKB

controls, cavity, LLRF, injection

2137

T. Kobayashi, K. Akai, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri
KEK, Ibaraki, Japan
H. Deguchi, K. Hayashi, J. Mizuno
Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan
K. Hirosawa
Sokendai, Ibaraki, Japan

For SuperKEKB, new low level RF (LLRF) control systems has ben developed and they worked successfully in the first beam commissioning (Phase-1) of SuperKEKB, which was accomplished in 2016. Damping ring (DR) was newly constructed for positron beam injection, in order to make significantly emittance smaller for SuperKEKB. The beam commissioning of DR will be conducted in JFY2017 for the Phase-2 commissioning. Phase-2 is scheduled in the last quater of JFY2017. DR has an RF station, and two cavities (or three cavities in future) are driven by a klystron. New LLRF control system for DR (DR-LLRF) was also developed and installed. RF frequency of DR operation is common with the main storage rings (MR) of SuperKEKB. The good performance of DR-LLRF was demonstrated in test operation, and RF conditioning of the pair of two cavities was successfully completed in June 2017. This paper reports the detail of the performance results of DR-LLRF controls, and also the other some relevant issues in LLRF controls for DR, including the master oscillator system (synchronization with the injection linac), are introduced.

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WEPAL002

Improvement of Personnel and Machine Protection System in Superkekb Injector Linac

operation, PLC, controls, gun

2140

I. Satake, H. Honma, A. Shirakawa, N. Toge
KEK, Ibaraki, Japan

Since summer of 2010, the radiation control area for the KEK electron positron injector linac had been split at the around 3 GeV point by a concrete wall into upstream and downstream parts with independent beam sources. This was so as to allow operation of the downstream part for beam injection into photon factory rings while construction and development of new electron guns proceed in the upstream part. In summer of 2017, this arrangement was revised and the entire injector linac was reconsolidated into a single radiation control area. This was in conjunction with the introduction of the 1.1 GeV positron damping ring for Phase-II operation of SuperKEKB and successful development of new electron RF guns in the far upstream part of the linac. Along with this reconsolidation, the personnel and machine protection system was modified and improved. Interlock signal lines for the damping ring and RF guns were added. The operation panel of the main console was modified accordingly. In addition, the screen displays of the interlock status were updated. In this paper we report on the renewed system of KEK injector linac in detail.

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WEPAL006

Experimental Study of a Differential Beam Intensity Monitoring for the CIADS LINAC

experiment, pick-up, monitoring, machine-protect

2155

Z.P. Xie, Y.K. Ding, J. Liang
Hohai University, Nanjing, People's Republic of China
Y. He, Z.J. Wang, J.X. Wu, Y. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by the National Natural Science Foundation of China (Grant No. 91026001) and the Fundamental Research Funds for the Chinese Central Universities
A BPM based beam loss monitoring scheme for the China initiative accelerator driven subcritical (CIADS) facility has been proposed for the MEBT section of its high power Linac. In this scheme, a differential beam monitoring algorithm is utilized that relies on beam intensity measurements using BPM electrodes. Discussions of the experimental results for the scheme are presented. Further experiments have been performed with some promising results. This paper describes the experimental results with some analyses on measurement errors of the system. The proposed physical design of this system is described and further development is presented.

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WEPAL008

Low-level RF System for The Chinese ADS Front-end Demo Linac

controls, LLRF, cavity, interface

2159

J.Y. Ma, Z. Gao, G. Huang, L.P. Sun
IMP/CAS, Lanzhou, People's Republic of China

The Chinese ADS Front-end Demo Linac (FDL) is constructed to demonstrate the technology of superconducting linac with high proton beam loading of CW 10mA. The low-level RF (LLRF) control system for the ADS FDL is developed by IMP, and the cooperation with TRIUMF. In the normal conducting (NC) section, the normal RF feedback control loop is used. In order to stable the superconducting (SC) cavity with loaded high RF power, the self excited loop with phase locked mode was used on the SC linac. This paper introduces the LLRF control system for buncher, SC linac, and the structures of hardware and the functions of software of these LLRF systems. The operating status of the LLRF systems is also reported.

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WEPAL010

Review of the ELI-NP-GBS Low Level RF and Synchronization Systems

LLRF, laser, electron, timing

2162

L. Piersanti, D. Alesini, M. Bellaveglia, F. Cardelli, M. Diomede, A. Gallo, V. Martinelli
INFN/LNF, Frascati (Roma), Italy
B.B. Baricevic, R. Cerne, G. Jug
I-Tech, Solkan, Slovenia
M. Diomede
Sapienza University of Rome, Rome, Italy
P.N. Dominguez
Menlo Systems GmbH, Martinsried, Germany

ELI-NP is a linac based gamma-source in construction at Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy and with intensity and brilliance well beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and a 515 nm intense laser pulse. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation at 100 Hz repetition rate. A total of 13 klystrons, 3 S-band (2856 MHz) and 10 C-band (5712 MHz) will power a total of 14 Travelling Wave accelerating sections (2 S-band and 12 C-band) plus 3 S-band Standing Wave cavities (a 1.6 cell RF gun and 2 RF deflectors). Each klystron is individually driven by a temperature stabilized LLRF module for a maximum flexibility in terms of accelerating gradient, arbitrary pulse shaping (e.g. to compensate beam loading effects in multi-bunch regime) and compensation of long-term thermal drifts. In this paper, the whole LLRF system architecture and bench test results, the RF reference generation and distribution together with an overview of the synchronization system will be described.

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WEPAL013

Design of the Diagnostic Stations for the ELI-NP Compton Gamma Source

radiation, electron, optics, simulation

2173

M. Marongiu
INFN-Roma, Roma, Italy
M. Castellano, E. Chiadroni, G. Di Pirro, G. Franzini, A. Giribono, V. Shpakov, A. Stella, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy

A high brightness electron Linac is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches, 16 ns spaced, with a nominal charge of 250 pC will collide with the laser beam in the interaction point. Electron beam spot size is measured with optical transition radiation (OTR) profile monitors. Furthermore, OTR angular distribution strongly depends on beam energy. Since OTR screens are typically placed in several positions along the Linac to monitor beam envelope, one may perform a distributed energy measurement along the machine. This will be useful, for instance, during the commissioning phase of the GBS in order to verify the correct functionality of the C-Band accelerating structures, due to the fact that there are OTR screens after each accelerating module. This paper deals with the studies of different optic configurations to achieve the field of view, resolution and accuracy in order to measure the energy of the beam. Several configurations of the optical detection line will be studied with simulation tools (e.g. Zemax).

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WEPAL014

Non-Distructive 2-D Beam Profile Monitor Using Gas Sheet in J-PARC LINAC

injection, electron, vacuum, cavity

2177

J. Kamiya, Y. Hikichi, M. Kinsho, A. Miura, N. Ogiwara
JAEA/J-PARC, Tokai-mura, Japan

We have been developed a beam profile monitor using interaction between the beam and the gas molecules distributed in sheet shape*. Generated luminescence or ions by passing the beam through the gas sheet has the information of cross-section shape of the beam. The gas sheet beam monitor will become a useful tool to measure the profile of high power beams because it has no breakable element such as wires and a 2-D beam profile at a certain position of beam line can be immediately obtained by just injecting the gas. Previously, the development of the gas sheet generator and successful demonstration of the beam profile measurement were reported. This time, we applied a gas sheet monitor to J-PARC LINAC, where the negative hydrogen atoms (H⁻) are accelerated to the energy of 400 MeV in the normal operation. Most challenging factor was the development of the gas sheet monitor system, which generates the enough dense gas sheet to detect the clear image of the beam profile without harmful effect on the ultra-high vacuum in the beam line. We will report the gas sheet beam monitor system for J-PARC LINAC and the results of the first measurement of the beam profile.
* N. Ogiwara, et al., Proceedings of IPAC2016, p.2102.

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WEPAL016

Tensile Fracture Test of Metallic Wire of Beam Profile Monitors

electron, cavity, beam-loading, controls

2183

A. Miura, Y. Kawane, K. Moriya
JAEA/J-PARC, Tokai-mura, Japan
S. Fukuoka
Nihon Koshuha Co. Ltd, Yokohama, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan

In order to mitigate the beam loss during a beam transportation in a high-brilliant accelerator facilities, wire-based profile monitors are used to measure by both transverse and longitudinal beam profiles using wire-scanner monitors (WSMs) and bunch-shape monitors (BSMs) for the tuning of quadrupole magnets and bunching cavities. Signals are come from the direct interaction between a metallic wire and beam. We have used the tungsten wire as a high melting-point material by estimation of heat loading during the impact of beam particles. In addition, a spring is applied for the relaxing a sag under wire's own weight. A tensile fracture test is conducted by supplying an electrical current as a simulated beam-heat loading. As the results, we obtained the relation between the thermal limit to break down and tension loading of tungsten wire.

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WEPAL017

Adaptive Feedforward Control Design Based on Simulink for the J-PARC LINAC LLRF System

controls, LLRF, cavity, simulation

2187

S. Li
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Z. Fang, Y. Fukui, K. Futatsukawa, F. Qiu
KEK, Ibaraki, Japan
S. Mizobata, Y. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In j-parc linac, for dealing with high beam loading effect, an adaptive feedforward control method which based on iterative learning control was put forward. At the same time, in order to verify its effectiveness before it is officially put into use, an llrf system simulation model was built in simulink, matlab. In this paper, the architecture of llrf system simulation model will be introduced. The result of iterative learning control (ILC) is summarized.

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WEPAL018

A Non-destructive 2D Profile Monitor Using a Gas Sheet

experiment, electron, proton, target

2190

N. Ogiwara, Y. Namekawa
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
M. Fukuda, K. Hatanaka, T. Shima, K. Takahisa
RCNP, Osaka, Japan
Y. Hikichi, J. Kamiya, M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan
Y. Hori
KEK, Tokai, Ibaraki, Japan

We are developing a non-destructive and fast-response beam profile monitor using a dense gas sheet target. To make a gas sheet, we use the beaming effect, which is well known in vacuum science and technology. The emitted molecules through a long rectangular channel, which has a very small ratio of the gap to the width, are forced to concentrate on a plane. The gas sheet with a thickness of 1.5 mm and the density of 2×10^-4 Pa was easily generated by the combination of the deep slit and the thin slit. Here, the gas sheet was produced by the deep slit, and the shape of the sheet was improved by the thin slit. The usefulness of this monitor was shown by the following experiments: 1) For the electron beam of 30 keV with a diameter greater than 0.35 mm, the position and the two-dimensional profiles were well measured using the gas sheet. 2) Then the profiles of the 10 and 400 MeV proton beam with a current of several microamperes were well measured, too. 3) Recently, the profiles of the 400 MeV H⁻ ion beams in J-PARC linac were measured.

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WEPAL021

Study of a Tuner for a High-Accuracy Bunch Shape Monitor

insertion, resonance, cavity, electron

2200

K. Moriya, Y. Kawane, A. Miura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan

In the J-PARC Linac, development and higher precision of Bunch Shape Monitor (BSM) have been progressed for measuring the longitudinal beam distribution. To transform a longitudinal beam-profile into transverse one with an rf field, we need the field having an acceleration synchronizing frequency. An rf deflector of BSM consists of a half λ cylindrical cavity and two electrodes for deflection. In general, the resonance frequency can be tuned by adjusting the electrode length. We designed the new tuner with CST Studio. We can control the resonance frequency by Adjusting not only the electrode length but the cavity volume. We found the optimum lengths of electrode and volume for tuning. We introduce development of the new rf tuner for BSM in this paper.

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WEPAL022

Operating Experience of Water Cooling System in the J-PARC LINAC and RCS

acceleration, diagnostics, klystron, DTL

2203

K. Suganuma, K. Fujirai, M. Kinsho, P.K. Saha, Y. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The cooling system for the J-PARC LINAC and RCS uses a total of 25 circulation pumps to cool the accelerator devices. In February 2017, we experienced damage of circulation pumps due to low flow rate, and started the development of an abnormality detection system concentrating on the vibration measurements of the circulation pumps. In this report, the vibration measurement results of the coolant circulation pumps and the development status of abnormality detection through multivariate analysis using vibration values are discussed.

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WEPAL029

FLUTE Diagnostics Integration

controls, diagnostics, cavity, interface

2227

M. Yan, A. Bernhard, E. Bründermann, S. Funkner, A. Malygin, S. Marsching, W. Mexner, A. Mochihashi, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, T. Schmelzer, M. Schuh, N.J. Smale, P. Wesolowski, S. Wüstling
KIT, Karlsruhe, Germany
I. Križnar
Cosylab, Ljubljana, Slovenia

FLUTE (Ferninfrarot Linac- Und Test-Experiment) will be a new compact versatile linear accelerator at KIT. Its primary goal is to serve as a platform for a variety of accelerator studies as well as to generate strong ultra-short THz pulses for photon science. The machine consists of an RF gun, a traveling wave linac and a D-shaped bunch compressor chicane with corresponding diagnostics sections. In this contribution, we report on the latest developments of the diagnostics components. An overview of the readout and control system integration will be given.

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WEPAL035

The Synchronization System of the Thomx Accelerator

HOM, electron, laser, distributed

2243

N. Delerue, V. Chaumat, R. Chiche, N. ElKamchi, H. Monard, F. Wicek
LAL, Orsay, France
B. Lucas
CNRS LPGP Univ Paris Sud, Orsay, France

Funding: CNRS and ANR
The ThomX compact light source uses a 50 MeV ring to produce X-rays by Compton scattering. For historical reasons the linac and the ring could not operate at harmonic frequencies of each other. A heterodyne synchronization system has been designed for this accelerator. This synchronization is based on mixing the two RF frequencies to produce an heterodyne trigger signal and that is then distributed to the users. Bench tests of the system has demonstrated a jitter of less than 2 ps. We describe here this synchronization system.

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WEPAL036

Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System

extraction, injection, timing, kicker

2247

P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang
IHEP, Beijing, People's Republic of China
L. Wang
CSNS, Guangdong Province, People's Republic of China

Funding: Institute of High Energy Physics， Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China
Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.

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WEPAL070

HLS System to Measure the Location Changes in Real Time of PAL-XFEL Devices

FEL, alignment, real-time, survey

2345

H. J. Choi, J.H. Han, H.-S. Kang, S.H. Kim, H.-G. Lee, S.B. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

All components of PAL-XFEL (Pohang Accelerator Laboratory's X-ray free-electron laser) were completely installed in December 2015, and Hard X-ray 0.1nm lasing achieved through its beam commissioning test and machine study on March 16, 2017. The beam line users has been performing various tests including pump-probe X-ray scattering, time-resolved x-ray liquidography, etc in the hard x-ray beam line since March 22. The energy and flux of x-ray photon beam generated from XFEL and synchronization timing should be stable to ensure successful time-resolved tests. Several parts that comprise the large scientific equipment should be installed and operated at precise three-dimensional location coordinates X, Y, and Z through survey and alignment to ensure their optimal performance. As time goes by, however, the ground goes through uplift and subsidence, which consequently changes the coordinates of installed components and leads to alignment errors ΔX, ΔY, and ΔZ. As a result, the system parameters change, and the performance of the large scientific equipment deteriorates accordingly. Measuring the change in locations of systems comprising the large scientific equipment in real time would make it possible to predict alignment errors, locate any region with greater changes, realign components in the region fast, and shorten the time of survey and alignment. For this purpose, a HLS's (hydrostatic leveling sensor) with 0.2um of resolution are installed and operated in a waterpipe of total length 1km in the PAL-XFEL building. This paper is designed to introduce the operating principle of the HLS, the installation and operation of the HLS system, and how to utilize the HLS system in order to ensure beam stabilization.

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WEPAL072

A Novel Longitudinal Laserwire to Non-Invasively Measure 6-Dimensional Bunch Parameters at High Current Hydrogen Ion Accelerators

laser, emittance, detector, simulation

2349

S.M. Gibson, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
S.E. Alden, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

Funding: We acknowledge funding by the STFC Grant ST/P003028/1 and the John Adams Institute at Royal Holloway, University of London.
Optical methods for non-invasive beam diagnostics of high current H⁻ ion accelerators have been developed in recent years*, **. Such laserwires typically measure a 1D beam profile and/or 2D transverse emittance from the products of photo-detached ions as a laser beam is scanned across the H⁻ beam. For laser pulse durations (~80ns) longer than the RF period (~3ns), the detector integrates many complete bunches, enabling only transverse beam monitoring. This paper presents a new technique to capture a series of time resolved transverse emittance measurements along the bunch train. A fast (~10ps) pulsed laser photo-detaches ions within each bunch and is synchronized to sample consecutive bunches at certain longitudinal positions along each bunch. A fast detector records the spatial distribution and time-of-flight of the neutralized H⁰, thus both the transverse and longitudinal emittance are reconstructed. We present simulations of a time varying pulsed laser field interacting within an H⁻ bunch, and estimate the yield, spatial and time distributions of H⁰ arriving at the detector. We summarise the design of a recently funded longitudinal laserwire being installed in FETS at RAL, UK.
* NIM-A, 830, p526-531, T. Hofmann et al
** T. Hofmann et al, 'Commissioning of the Operational Laser Emittance Monitors for LINAC4 at CERN' IPAC18.

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WEPAL074

Commissioning of the Operational Laser Emittance Monitors for LINAC4 at CERN

laser, electron, detector, emittance

2357

T. Hofmann, G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
F. Roncarolo
CERN, Geneva, Switzerland

A laser-based emittance monitor has been developed to non-invasively measure the transverse emittance of the LINAC4 H⁻ beam at its top energy of 160MeV. After testing several sub-systems of the instrument during linac commissioning at intermediate energies, two instruments are now permanently installed. These instruments use a pulsed laser beam delivered to the accelerator tunnel by optical fibres before final focusing onto the H⁻ beam. The photons in the laser pulse detach electrons from the H⁻ ions, which can then be deflected into an electron multiplier. In addition, the resulting neutral H⁰ atoms can be separated from the main beam by a dipole magnet before being recorded by downstream diamond strip-detectors. By scanning the laser in the horizontal and vertical plane the beam profiles are obtained from the electron signals and the emittance can be reconstructed by the H⁰ profiles at the diamond detectors. This paper describes the final system layout that consists of two independent instruments, each measuring profile and emittance of the H⁻ beam in the horizontal and vertical plane and discusses the preliminary commissioning results.

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WEPMF004

The Saclay Test Stand for Conditioning the ESS RFQ Power Couplers at High RF Power

cavity, rfq, vacuum, interface

2375

N. Misiara, A.C. Chauveau, D. Chirpaz-Cerbat, P. Daniel-Thomas, M. Lacroix, L. Maurice
CEA/IRFU, Gif-sur-Yvette, France
M. Desmons, A. Dubois, A. Gaget, L. Napoly, M. Oublaid, G. Perreu, O. Piquet, B. Pottin, Y. Sauce
CEA/DRF/IRFU, Gif-sur-Yvette, France

The RF power coupler system for the RFQ of the ESS LINAC will feed 1.6 MW peak power through two coaxial loop couplers for a 352.21 MHz operation at the expected duty cycle. A specific test stand has been designed to condition the power couplers, and test the different auxiliary components in the nominal conditions of the RFQ. The power couplers were successfully assembled, installed and instrumented on the test cavity. This paper presents the general layout of the test stand, the installation and preparation of the power couplers for their conditioning at high RF power up to the ESS nominal conditions.

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WEPMF038

Microphonics Suppression in the CBETA Linac Cryomodules

cavity, cryomodule, SRF, controls

2447

N. Banerjee, J. Dobbins, F. Furuta, G.H. Hoffstaetter, R.P.K. Kaplan, M. Liepe, P. Quigley, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was performed through the support of New York State Energy Research and Development Agency. The linac cryomodules were constructed with funding from the National Science Foundation.
The Cornell-BNL ERL Test Accelerator (CBETA) is a new multi-turn energy recovery linac currently under construction at Cornell University. It uses two superconducting linacs, both of which are susceptible to microphonics detuning. The high-current injector accelerates electrons to 6 MeV and the main linac accelerates and decelerates electrons by 36 MeV. In this paper, we discuss various measures taken to reduce vibrations caused by instabilities and flow transients in the cryogenic system of the main linac cryomodule. We further describe the use of a Least Mean Square algorithm in establishing a stable Active Microphonics Compensation system for operation of the main linac cavities.

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WEPMF053

XFEL Modulators with Pulse Cables

FEL, operation, klystron, radiation

2487

H.-J. Eckoldt, S. Choroba, T. Grevsmühl, A. Hauberg, J. Havlicek, N. Heidbrook, K. Machau, N. Ngada
DESY, Hamburg, Germany
M. Frei, S.G. Keens, T.H. Strittmatter
Ampegon AG, Turgi, Switzerland
H. Leich
DESY Zeuthen, Zeuthen, Germany

The modulators of the European XFEL produce high voltage, at the 10kV level, having a power of up to 16.8 MW for 1.54 ms. The operation frequency of the super-conducting inac is 10 Hz. The series production of the 29 modulators started in 2012. The first modulator began operation in 2014 and the start of linac was beginning 2017. The R&D phase for the modulators started directly with the development of superconducting cavities. Besides the pulse generation, the modulator had to suppress the 10 Hz repetition rate in order not to disturb the grid. Another unique demand was the development of pulse cables. Since the power RF had to be generated in the tunnel, the klystrons were installed near the cavities. However, the modulators had to be installed outside of the tunnel for space, maintenance reasons and radiation concerns. This transmission of high power pulses via long cables is unique in the world and the suppression of EMI effects was mandatory. During the first year operation no EMI disturbances of other systems were detected and the modulator system works as expected.

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WEPMF067

A High Gradient Solution for Increasing the Energy of the FERMI Linac

FEL, electron, wakefield, laser

2525

C. Serpico, I. Cudin, S. Di Mitri, N. Shafqat, M. Svandrlik
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Bopp, R. Zennaro
PSI, Villigen PSI, Switzerland

FERMI is the seeded Free Electron Laser (FEL) user facility at Elettra laboratory in Trieste, operating in the VUV to soft X-rays spectral range. In order to extend the FEL spectral range to shorter wavelengths, a feasibility study for increasing the Linac energy from 1.5 GeV to 1.8 GeV is actually going on. The design of new S-band accelerating structures, intended to replace the present Backward Travelling Wave sections, is presented. Such design is tailored for high gradient operation, low breakdown rates and low wakefield contribution. In this paper, we will also present the first, short prototype that has been built in collaboration with Paul Scherrer Institute (PSI).

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WEPMF082

Design and Construction of the CERN PS Booster Charge Exchange Injection Chicane Bumpers

injection, vacuum, septum, simulation

2575

B. Balhan, C. Baud, J.C.C.M. Borburgh, M. Hourican
CERN, Geneva, Switzerland

In the framework of the LIU project and the connection from LINAC4 to PS Booster, the 160 MeV H⁻ beam will be injected horizontally into the PSB by means of one charge-exchange injection system for each PSB ring. A set of four outside vacuum pulsed dipole magnets (BSW) creating the required injection bump has been designed and built. The dynamic requirements for the bump ramp down determine, to a large extent, the field homogeneity due to the eddy currents induced in the corrugated Inconel vacuum chamber. Magnetic simulations were performed to determine the field harmonics during bump ramp down, and the results subsequently used for the dynamic tracking of the beam during injection. The mechanical design and construction of the magnets will be briefly outlined, and the article will conclude with the magnetic measurements of the magnets. The magnetic performance of the as built magnets will be compared with the simulations and the influence of the vacuum chambers on the magnetic field will be quantified.

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WEPMK007

INFN-LASA Design and Prototyping Activity for PIP-II

cavity, HOM, coupling, operation

2640

A. Bignami, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
S. Pirani
ESS, Lund, Sweden

The design of the PIP-II medium-β, 5-cell, 650 MHz SRF elliptical cavity and the first steps of its prototyping activity are here presented. A design based on a three dies fabrication model has been chosen and fully characterized in terms of electromagnetic and mechanical parameters. Goal of the optimization has been to realize a highly performant cavity for CW operation with reasonably good performances when pulsed. A prototyping phase started with the production of three single-cell cavities used to validate the LASA model and to develop an optimal recipe for RF surface treatment according to the state-of-the-art of the high-Q frontier.

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WEPMK015

Optimization of Vertical Electro-Polishing Process: Experiments with Updated Cathode on Single-Cell Cavity and Performance Achieved in Vertical Test

cavity, cathode, SRF, superconductivity

2662

F. Éozénou, L. Maurice
CEA/DSM/IRFU, France
P. Carbonnier, C. Madec, Th. Proslier, C. Servouin
CEA/DRF/IRFU, Gif-sur-Yvette, France
V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan

Marui Galvanizing Co.Ltd., and CEA have been studying Vertical Electro-Polishing (VEP) on Nb single-cell accelerating superconducting accelerator cavity with the goal of mass-production and cost-reduction, in collaboration with KEK within TYL-FJPPL Particle Physics Laboratory. Marui has invented and patented a rotative cathode called ‘i-Ninja'. The version 5 has been tested for the first time in Europe at CEA Saclay. The four wings of the cathode remove efficiently, bubbles of hydrogen, and the chosen parameters make it possible to achieve better surface and uniform material removal compared to VEP with a fixed cathode. The effect of the temperature of the cavity walls on current oscillations has been precisely studied. Two single-cell cavities have been electro-polished and tested at 2 K in vertical cryostat and the results will be presented.

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WEPML002

Design of 650 MHz Tuner for PIP-II Project

cavity, interface, simulation, experiment

2671

Y.M. Pischalnikov, S. Cheban, J.C. Yun
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Proton Improvement Plan (PIP) II project at Fermilab is a proton driver linac which will use of five different cavity geometries including a 650 MHz 5-cell elliptical cavities that will operate in RF-pulse mode. Detuning of these cavities by Lorentz Forces will be large and strongly depend of the stiffness of the cavity's tuner. First prototype tuner built and tested warm [1,2]. Measured stiffness of the prototype tuner was below 30kN/mm instead of expected from simulation 70kN/mm [2]. Significant effort has been invested into understanding discrepancy between simulation and experimental data that led to newest tuner design. Updated 'dressed cavity-helium vessel-tuner' model provided consistent results between ANSYS simulations and experiment results. Modified tuner design and analysis in limitations for overall 'cavity/tuner system' stiffness will be presented.

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WEPML005

Testing of SSR1 Production Tuner for PIP-II

cavity, SRF, niobium, cryomodule

2681

J.P. Holzbauer, D. Passarelli, Y.M. Pischalnikov
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The PIP-II project at Fermilab is a proton driver linac calling for the use of five different, novel cavity geometries. Prototyping at Fermilab is in the advanced stages for the low-beta single-spoke resonator (SSR1) and associated technologies. A production tuner design has been fabricated and tested, both warm and cold in the Spoke Test Cryostat (STC). This paper will present the detailed studies on this tuner, including slow motor/piezoelectric tuner range and hysteresis as well as dynamic mechanical system characterization.

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WEPML039

Design of the Two-Gap Superconducting Re-Buncher

cavity, heavy-ion, simulation, proton

2779

M. Gusarova, W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia
W.A. Barth, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth, M. Miski-Oglu
HIM, Mainz, Germany
M. Basten, M. Busch
IAP, Frankfurt am Main, Germany
M. Gusarova
JINR, Dubna, Moscow Region, Russia

A new design of a spoke cavity for low relative velocities of heavy ions has been elaborated. Simulation results for a 2-gap spoke cavity with a resonance frequency of 216.816 MHz and a relative velocity of 0.07с are presented.

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WEPML040

Further Tests on the Final State of the SC 325 MHz CH-Cavity and Coupler Test Bench Update

cavity, heavy-ion, framework, SRF

2783

M. Busch, M. Basten, J. List, P. Müller, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
W.A. Barth, J. List
GSI, Darmstadt, Germany
W.A. Barth
HIM, Mainz, Germany
W.A. Barth
MEPhI, Moscow, Russia

Funding: Work supported by BMBF Contr. No. 05P15RFBA
At the Institute for Applied Physics, Goethe-University Frankfurt, a sc 325 MHz CH-cavity has been developed and successfully tested up to 14.1 mV/m and has now reached the final production stage with the helium vessel welded to the frontal joints of the cavity and final processing steps have been performed. Further tests in a vertical and horizontal environment are being prepared for intensive studies. This cavity is a prototype for envisaged beam tests with a pulsed ion beam at 11.4 AMeV. In this contribution the results of the performed RF tests are being presented. Furthermore, first measurements of the recently installed 217 MHz coupler test bench are shown.

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WEPML041

Comparative Study of Low Beta Multi-Gap Superconducting Bunchers

cavity, heavy-ion, proton, accelerating-gradient

2786

K.V. Taletskiy, W.A. Barth, M. Gusarova, S. Yaramyshev
MEPhI, Moscow, Russia
W.A. Barth, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth, M. Miski-Oglu
HIM, Mainz, Germany
M. Basten, M. Busch
IAP, Frankfurt am Main, Germany
M. Gusarova
JINR, Dubna, Moscow Region, Russia

The results of a comparative study of low beta multi-gap superconducting bunchers for 216.816 MHz and a relative velocity of 0.07с with dedicated limitations of the overall geometrical dimensions are presented. A comparison of electrodynamic, mechanical and thermal properties of 3-gap and 2-gap cavities is shown.

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WEPML045

Infrastructure for Superconducting CH-Cavity Preparation at HIM

cavity, vacuum, SRF, heavy-ion

2796

T. Kürzeder, K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, M. Miski-Oglu, E. Riehn
HIM, Mainz, Germany
K. Aulenbacher, R.G. Heine, T. Stengler
IKP, Mainz, Germany
W.A. Barth, S. Yaramyshev
GSI, Darmstadt, Germany
F. Hug
KPH, Mainz, Germany

A superconducting cw LINAC for heavy ions is currently under development at GSI in Darmstadt and HIM in Mainz. This Linac is based on 217 MHz multigap bulk niobium Crossbar H-mode RF-cavities. In order to treat and prepare RF-cavities with such a complex geometry a new cleanroom facility has been already built at the Helmholtz-Institut in Mainz. All tools and machines inside the cleanroom can handle cavities with up to 800 mm in diameter and with up to 1300 mm in length. In its ISO-class 6 and 4 zones, respectively it features a large ultrasonic and conductance rinsing bath, a high pressure rinsing (HPR) cabinet and a vacuum oven. The HPR cabinet has an inside clearance of 1.4 m. The large cavities sit on a rotating table, while the rising wand moves vertically up and down. Due to the crossbar structure of the RF-cavities the HPR device allows for off axis-rinsing in their quadrants. For RF testing a 52 m² (4 m x 13 m) concrete shielded area with sufficient liquid helium and nitrogen supply is located next to the cleanroom and the cryo-module assembly area. We will report on the new SRF infrastructure in Mainz and the commissioning of the new high pressure rinsing cabinet.

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WEPML046

Multipactor Discharge in Superconducting Accelerating CH Cavities

multipactoring, electron, cavity, heavy-ion

2800

M. Gusarova, D. I. Kiselev
MEPhI, Moscow, Russia
F.D. Dziuba, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
M. Gusarova
JINR, Dubna, Moscow Region, Russia

The results of numerical simulations of multipacting discharge in a superconducting accelerating CH cavity are presented in this paper. The localization of multipactor trajectories in the 15-gap 217 MHz superconducting (sc) CH cavity at various levels of accelerating voltage is considered.

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WEPML051

Improvement of the Chopper System for rf Deflector at the J-PARC Linac

controls, timing, cavity, operation

2816

K. Futatsukawa, Z. Fang, Y. Fukui
KEK, Ibaraki, Japan
Y. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan
S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In the J-PARC linac, the RF deflector has been operated to kick the wasted beam and to shape the intermediate-pulse like the comb structure. Then about 50% of the beam current is removed by leading the scraper and the rest beam current is injected to the downstream synchrotron ring RCS. The fast rising time and falling time, the cavity with low loading Q value in the chopper system are required to decrease the incomplete kicked beam. However, there was the ringing of the RF field on the chopper cavity, and it influenced the beam rising time. The chopper controllers, which has the fast RF -switch to make the particular RF according to the intermediate-pulses, were improved for the RF falling time by outputting short pulses with inverting phase. The beam study for the new system was successfully done. In this paper, I would like to introduce this system and to show the results of the beam study.

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THXGBE1

6D Beam Measurement, Challenges and Possibilities

simulation, rfq, experiment, quadrupole

2890

A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA
B.L. Cathey
ORNL RAD, Oak Ridge, Tennessee, USA

A system to measure the full 6D beam parameters (not 3x2D) has been built at the SNS RFQ test stand. Such a measurement will allow detailed analysis of the beam physics from a properly measured input term. This invited provides an overview of the principles and design of this system, and reports on status and results.

Slides THXGBE1 [4.471 MB]

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THYGBF4

Accelerator Physics Advances in FRIB (Facility for Rare Isotope Beams)

cavity, MMI, ECR, ECRIS

2950

P.N. Ostroumov, N.K. Bultman, M. Ikegami, S.M. Lidia, S.M. Lund, G. Machicoane, T. Maruta, A.S. Plastun, G. Pozdeyev, X. Rao, J. Wei, T. Xu, T. Yoshimoto, Q. Zhao
FRIB, East Lansing, USA
C.Y. Wong
NSCL, East Lansing, Michigan, USA

Funding: Work supported by the U.S. DOE Office of Science under Cooperative Agreement DE-SC0000661 and the NSF under Cooperative Agreement PHY-1102511, the State of Michigan and Michigan State University.
This paper presents recent developments of accelerator physics related topics for the Facility for Rare Isotope Beams (FRIB) being built at Michigan State University. While extensive beam dynamics simulations including all known errors do not show uncontrolled beam losses in the linac, ion beam contaminants extracted from the ECR ion source together with main ion beam can produce significant losses after the charge stripper. These studies resulted in development of beam collimation system at relatively low energy of 16 MeV/u and room temperature bunchers instead of originally planned superconducting ones. Commissioning of the Front End enabled detailed beam physics studies accompanied with the simulations using several beam dynamics codes. Settings of beam optics devices from the ECR to MEBT has been developed and applied to meet important project milestones. Similar work is planned for the beam commissioning of the first 3 cryomodules in the superconducting linac.

Slides THYGBF4 [11.092 MB]

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THPAF011

Design of 4 Ampere S-Band LINAC Using Slotted Iris Structure for HOM Damping

HOM, damping, target, dipole

2965

J. Pang, S. Chen, X. He, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
S. Pei, H. Shi, J.R. Zhang
IHEP, Beijing, People's Republic of China

Funding: Key Laboratory of Pulsed Power, CAEP (Contract NO. PPLF2014PZ05) Key Laboratory of Particle Acceleration Physics &Technology，IHEP, CAS (Contract Y5294109TD)
An S-band LINAC with the operating frequency of 2856 MHz and beam current of 4 A was designed for flash X-ray radiography for hydrodynamic test. The optimization of the parameters of the LINAC was processed to obtain the minimum beam radius and the maximum energy efficiency. For the purpose of reducing the beam orbits offset at the exit of LINAC, a slotted iris accelerating structure would be employed to suppress the transverse Higher Order Modes (HOMs) by cutting four radial slots in the iris to couple the HOMs to SiC loads. In this paper, we present the design of the LINAC and the results of beam dynamic analysis.

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THPAF017

Improvement of RF Field Phase and Amplitude Errors Simulations in TraceWin Code

cavity, simulation, diagnostics, beam-losses

2983

D. Uriot
IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France

Funding: This work is supported by the European Atomic Energy Community's (EURATOM) H2020 Programme under grant agreement n°662186 (MYRTE project)
RF field phase and amplitude errors are usually not correctly simulated and it is a serious problem especially when in high intensity linear accelerators, the main losses are due to particle leaving the beam acceptance. This new development implemented in TraceWin fixes this issue. The objective is to improve the longitudinal beam dynamics simulation methods, by including more close-to-real models for the cavities tuning procedure. By this way, clear distinction should be done between static and dynamic errors and longitudinal diagnostics accuracy can be clearly defined according to beam dynamics results.

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THPAF019

Initial Performance of the Magnet System in the Splitter/Combiner Section of the Cornell-Brookhaven Energy-Recovery Linac Test Accelerator

quadrupole, dipole, cavity, optics

2986

J.A. Crittenden, A.C. Bartnik, R.M. Bass, D.C. Burke, J. Dobbins, C.M. Gulliford, Y. Li, D. Sagan, K.W. Smolenski, Turco, J. Turco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg
BNL, Upton, Long Island, New York, USA
D. Jusic
Cornell University, Ithaca, New York, USA

Funding: This work is supported by NSF award DMR-0807731, DOE grant DE-AC02- 76SF00515, and New York State Energy Research and Development Authority.
The Cornell-Brookhaven Energy-recovery Linac Test Accelerator is a four-pass, 150-MeV electron accelerator with a six-cell 1.3 GHz superconducting-RF linear accelerator and a fixed-field alternating-gradient (FFAG) return loop made up of Halbach-style quadrupole magnets. The optics matching between the linear accelerator and the return loop is achieved with a conventional magnet system comprised of 50 dipole magnets and 64 quadrupole magnets in four beamlines at each end of the linac. The 42-, 78-, 114- and 150-MeV electron beams are separated into independent vacuum chambers in order to allow for the path-length adjustment required by energy recovery. We report on the first beam tests of the initial installation of the splitter/combiner section at the exit of the linac. The vacuum system of the 42-MeV S1 line was installed during the first week of April. Nine dipole and four quadrupole magnets were installed and surveyed into position the following week, and the water cooling system was commissioned. A 6-MeV beam passed through the line on April~11 with no need for adjusting pre-set magnet excitation currents. One week later, time-of-flight measurements were used to calibrate and phase the individual superconducting RF cavities. The S1 magnet settings were then scaled up to achieve 5-cavity, 42-MeV operation through the first nine FFAG permanent-magnet quadrupoles. This initial Fractional Arc Test will conclude on May 18, when the installation of the remaining seven splitter/combiner lines and the return loop will begin. CBETA operations are scheduled to begin in early 2019.

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THPAF021

Start to End Simulation of the CBETA Energy Recovery Linac

lattice, simulation, optics, space-charge

2993

W. Lou, A.C. Bartnik, J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic, N. Tsoupas
BNL, Upton, Long Island, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, 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.
CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return line accepting all energies from 42 MeV to 150 MeV. We simulate a 6-dimensional particle distribution from the injector through the end of the dump line. Space charge forces are taken into account at the low energy stages. We compare results using field maps to those using simpler magnet models. We introduce random and systematic magnet errors to the lattice, apply an orbit correction algorithm, and study the impact on the beam distribution.

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THPAF023

The Beam Optics of the FFAG Cell of the CBETA ERL Accelerator

optics, quadrupole, focusing, electron

3000

W. Lou, A.C. Bartnik, J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic, N. Tsoupas
BNL, Upton, Long Island, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, 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.
The Cornell-Brookhaven Energy Recovery Linac Test Accelerator now under construction will accelerate electrons from 6 MeV to 150 MeV in four linac passes, using a single return line accepting all energies from 42 to 150 MeV. We describe the optical design of the machine, with emphasis on recent updates. We explain how we choose parameters for the wide energy acceptance return arc, taking into account 3D field maps generated from magnet designs. We give the final machine parameters resulting from iterations between desired lattice properties and magnet design. We modified the optics to improve the periodicity of the return arc near its ends and to create adequate space for vacuum hardware. The return arc is connected to the linac with splitter lines that serve to match the optics for each beam energy. We describe how matching conditions were chosen for the splitter lines and how we use them to control longitudinal motion. We simulate the injection and low energy extraction systems including space charge effects, matching the beam properties to the optical parameters of the rest of the machine.

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THPAF032

Simulation Study of an RF Injector for the LWFA Configuration at EuPRAXIA

injection, plasma, emittance, simulation

3025

J. Zhu, R.W. Aßmann, A. Ferran Pousa, B. Marchetti, P.A. Walker
DESY, Hamburg, Germany

The Horizon 2020 Project EuPRAXIA (EuropeanPlasma Research Accelerator with eXcellence In Applications) aims at producing a design report of a highly compact and cost-effective European facility with multi-GeV electron beams using a plasma accelerator. LWFA with external injection from an RF accelerator is one of the most promising configurations. In order to achieve the goal parameters for the 5 GeV, 30 pC electron beam at the entrance of the undulator, a high-quality electron beam with bunch length of less than 10 fs (FWHM) and matched beta functions (~1 mm) at the plasma entrance is required. In addition, from the compactness point of view, the injection energy is desired to be as low as possible. A hybrid compression scheme is considered in this paper and a detailed start-to-end simulation is presented.

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THPAF037

Bunch Compression and Turnaround Loops Design in the FCC-ee Injector Complex

emittance, dipole, sextupole, damping

3044

T.K. Charles, F. Zimmermann
CERN, Geneva, Switzerland
M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
K. Oide
KEK, Ibaraki, Japan

The Future Circular e⁺e⁻ Collider (FCC-ee) requires two 180-degree turnaround loops to transport the positron beam from the damping ring to the lower energy section of the linac. In addition bunch compression is required to reduce the RMS bunch length from 5 mm to 0.5 mm, prior to injection into the linac. A dogleg bunch compressor comprised of two triple bend achromat (TBAs) can achieve this compression. Sextupole magnets are incorporated into the bunch compressor design for chromaticity correction as well as optimisation of the second-order longitudinal dispersion, T₅₆₆, and to linearize the longitudinal phase space distribution. In this paper we present the design of the transport line and the bunch compressor. Measures to limit emittance growth due to coherent synchrotron radiation (CSR) are also discussed, because despite the relatively long bunch length, the large degree of bending required introduces cause for consideration of CSR.

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THPAF065

Semi-Empirical Hamiltonian Model for Elliptical Cavities

cavity, simulation, linear-dynamics, proton

3127

E. Laface, J. F. Esteban Müller
ESS, Lund, Sweden

We propose to use the sum of TM_0m0 modes to treat a radio-frequency superconducting elliptical cavity as a pill-box cavity with variable radius. The amplitudes of the different modes are obtained interpolating the field-map of the cavity with the model. Once the field is calculated, the Hamiltonian of the cavity is constructed and used to evaluate the transfer matrices associated to each step of the field-map. The multi-particle non-linear dynamics can also be evaluated using the Lie Transform of the Hamiltonian. The results are benchmarked against the ESS Linac Simulator contained in the OpenXAL suite.

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THPAF073

Beam Phase Space Tomography at Fast Electron Linac at Fermilab

experiment, lattice, coupling, MMI

3146

A.L. Romanov
Fermilab, Batavia, Illinois, USA

FAST linear accelerator has been commissioned in 2017. Experimental program of the facility requires high quality beams with well-defined properties. Solenoidal fields at photoinjector, laser spot shape, space charge forces and other effects can distort beam distribution and introduce coupling. This work presents results of a beam phase space tomography for a coupled 4D case. Beam was rotated in two planes with seven quads by 180 degrees and images from YaG screen were used to perform SVD based reconstruction of the beam distribution.

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THPAF082

Frequency Jump at Low Energies

rfq, emittance, bunching, simulation

3176

C. Zhang
GSI, Darmstadt, Germany
H. Podlech
IAP, Frankfurt am Main, Germany

One or more radio-frequency jumps are usually necessary for realizing a ≥100 AMeV/u proton or ion driver linac. Typically, such jumps happen in the range of β = 0.2-0.6 between the resonator structures fitting to this β-range, e.g. DTL, HWR, CCL or elliptical cavities. We propose to perform the first frequency jump already at low energies (β ≤ 0.1) between two RFQ accelerators, which can bring some unique advantages. First studies have been performed and the results proved that this idea is feasible and promising. Many efforts have been and are being made to address the most critical issue for the jumps i.e. the beam matching at the transition.

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THPAF083

LINAC-Multitool - an Open Source Java-Toolkit

cavity, GUI, MMI, simulation

3179

M. Schwarz, D. Bade, J. Corbet, H. Podlech
IAP, Frankfurt am Main, Germany

Funding: Work supported by BMBF contr. No. 05P15RFRBA and HIC for FAIR.
Dedicating more precious time to advanced research instead of spending it towards time-consuming routine tasks is a desirable goal in particle accelerator simulation and development. Requirements engineering was started at IAP in order to identify routine processes at our institute's R&D that can be automated or simplified. Results indicated that there were several areas to consider: Bead pull measurements, data processing and visualization for the beam dynamics code LORASR, CST field map processing for the use with TraceWin, conversion between different particle distribution data formats and more. Subsequently development of the LINAC-Multitool started to rationalize these processes and replace preexisting scripts also to ensure consistency of results and increase transparency and reliability of computation. In order to guarantee maintainability, expandability and platform independence, LINAC-Multitool is programmed using Java and will be open source. This contribution presents the current state of development.

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THPAK006

Design Status of the Beam Switchyard for ESSnuSB

proton, target, emittance, quadrupole

3215

E. Bouquerel
IPHC, Strasbourg Cedex 2, France

Funding: This project is now supported by the COST Action CA15139/EuroNuNet and EU/H2020 innovation programme ESSnuSB under grant agreement No 777419.
The ESSnuSB project, recently granted by the EU H2020 framework programme for a 4-year design study, proposes to use the proton linac (2 GeV, 5 MW) of the European Spallation Source (ESS) currently in construction in Lund (Sweden) to deliver a neutrino super beam. One of the work packages of this design study is dedicated to the primary proton beam-line completing the linac. It will mainly consist of an accumulator ring to compress the 2.86 ms long beam pulse to 1.32 μs and of a switchyard to distribute the protons onto a 4-target station. Dipoles, steerers, quadrupoles, collimators and several diagnostics will compose the switchyard to ensure the protons to hit the target with desired characteristics. This paper presents the objectives of this work package and the design status of this switchyard system.

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THPAK017

Higher Order Modes in China-ADS Demo Linac

dipole, HOM, cavity, higher-order-mode

3240

C. Zhang, Y. He, T.C. Jiang, R.X. Wang, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by Natural Science Foundation of China，No.11505253
The study of higher order modes excited in the China-ADS Linac has been presented in this paper. The effects of the cryogenic losses and the influence on beam of the higher order modes have been investigated.

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THPAK022

Beam Dynamic Simulation for the Beam Line from Charge Breeder to ALPI for SPES Project

rfq, simulation, experiment, quadrupole

3255

M. Comunian, L. Bellan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
A.V. Ziiatdinova
ITEP, Moscow, Russia
A.V. Ziiatdinova
MEPhI, Moscow, Russia

The SPES project (Selective Production of Exotic Species) is under development at INFN-LNL. This facility is intended for production of neutron-rich Radioactive Ion Beams (RIBs) by ISOL method. The +1 charged beam will be transformed to n+ charge by Charge Breeder (Electron Cyclotron resonance ion source) and reaccelerated by the ALPI (Acceleratore Lineare Per Ioni) superconducting Linac . This paper includes results of beam dynamic simulation at the beam line from Charge Breeder to ALPI.

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THPAK023

Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam

extraction, septum, positron, pulse-stretcher

3258

S. Guiducci, D. Alesini, M.E. Biagini, S. Bilanishvili, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, D.G.C. Di Giulio, L.G. Foggetta, A. Gallo, A. Ghigo, L. Kankadze, C. Milardi, R. Ricci, U. Rotundo, L. Sabbatini, M. Serio, A. Stella
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics.
* M. Raggi et al., EPJ Web Conf. 96 (2015) 01025

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THPAK047

Comparison of Profile Measurements and TRANSPORT Beam Envelope Predictions Along the 80-m LANSCE pRad Beamline

emittance, proton, diagnostics, simulation

3323

P.K. Roy, C. Pillai, C.E. Taylor
LANL, Los Alamos, New Mexico, USA

Funding: *Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
The Proton Radiography (pRad) experimental facility beam transport line is over 80 meters in length starting from the end of the LANSCE linear accelerator. The 800-MeV beam is transported through a beam line containing many bending and focusing elements before it reaches the pRad beam optics system where the beam spot size requirement is nominally 2 mm (RMS). Here we discuss the efforts to reconcile the beam transport inconsistencies (sizes) seen between comparisons of the beam sizes obtained using the LANL version of the beam envelope code TRANSPORT with those measured along the beam line. The transverse input beam parameters for the code were extracted from a fit to several wire-scanner measurements located in the downstream portion of the LINAC. The longitudinal input beam parameters were extrapolated from lower-energy information. Recently, new measurements were made of the beam line element locations and compared with legacy drawings. Beam envelope measurements made at various locations throughout the beam line using wire scanners and gated imaging systems were compared to the calculated results. The predicted beam envelopes and measured data agree within expected errors.
*Los Alamos National Laboratory (LA-UR-17-30876)

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THPAK049

Simulation Code Design for the Interpreted Language Using the Compiled Module

simulation, interface, EPICS, lattice

3327

K. Fukushima, M.A. Davidsaver, Z.Q. He, M. Ikegami, G. Shen, T. Yoshimoto, T. Zhang
FRIB, East Lansing, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DESC0000661.
We are planning to use two types of the accelerator simulation codes for FRIB (Facility for Rare Isotope Beams). One is the linear envelope tracking code "FLAME" for fast simulations. FLAME can calculate the FRIB-linac beam envelope within an order of ms. This is useful in systematic surveys, wide range optimizations and so forth. This code, written in C++, was designed with Python interface from the beginning. On the other hand, "Advanced-IMPACT" is the particle tracking code dedicated for precise and realistic calculations, which can simulate the particle losses, nonlinear and space-charge effects. This code is refactored from the Fortran code IMPACT-Z developed in LBNL. Both codes provide the compiled modules for Python to support flexible inputs and direct outputs management in memory. In other words, they can be directly connected to the modern scientific tools through the Python interface without delay in the data transport. In addition, these modules can accomplish the interactive simulation processes without losing computational efficiency. We report the knowledges applicable for other accelerator simulation codes among those obtained through these developments and designs.

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THPAK069

Open XAL Status Report 2018

cavity, MMI, diagnostics, GUI

3388

A.P. Zhukov, C.K. Allen, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
C.P. Chu, Y. Li
IHEP, Beijing, People's Republic of China
J.F. Esteban Müller, E. Laface, Y. Levinsen, N. Milas, C. Rosati
ESS, Lund, Sweden
P. Gillette, G. Normand, A. Savalle
GANIL, Caen, France
X.H. Lu
CSNS, Guangdong Province, People's Republic of China

The Open XAL accelerator physics software platform is being developed through an international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general purpose accelerator applications). This paper discusses progress in beam dynamics simulation, new RF models, and updated application framework along with new generic accelerator physics applications. We present the current status of the project, a roadmap for continued development and an overview of the project status at each participating facility.

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THPAK076

Development and Benchmarking of the IMPACT-T Code

rfq, SRF, simulation, space-charge

3408

H.P. Li, M.J. Easton, Y.R. Lu, Z. Wang
PKU, Beijing, People's Republic of China
J. Qiang
LBNL, Berkeley, California, USA

The multi-particle tracking code IMPACT-T is widely used to calculate the particle motion in high intensity linacs. The code is a self-consistent three-dimensional beam dynamics simulation toolbox that utilizes the particle-in-cell method in the time domain. In the collaboration between PKU and LBNL, an RFQ module was implemented to the IMPACT-T code, which enables simulations of the accelerator front-end. In order to benchmark the newly developed module in the IMPACT-T code, we have simulated the beam transport in Beijing Isotope Separation On-Line (BISOL) high intensity deuteron driver linac. It consists of a 3 MeV RFQ and 40 MeV superconducting HWR linac with five cryomodules. After comparing the simulation results with PARMTEQM, TraceWin and Toutatis, we obtained a very good agreement, which represents the validation of the new code.

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THPAK078

GPT-CSR: a New Simulation Code for CSR Effects

radiation, simulation, emittance, electromagnetic-fields

3414

S.B. van der Geer, M.J. de Loos
Pulsar Physics, Eindhoven, The Netherlands
A.D. Brynes, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
I.D. Setija, P.W. Smorenburg
ASML Netherlands B.V., Veldhoven, The Netherlands

For future applications of high-brightness electron beams, including the design of next generation FEL's, correct simulation of Coherent Synchrotron Radiation (CSR) is essential as it potentially degrades beam quality to unacceptable levels. However, the long interaction lengths compared to the bunch length, numerical cancellation, and difficult 3D retardation conditions make accurate simulation of CSR effects notoriously difficult. To ease the computational burden, CSR codes often make severe simplifications such as an ultra-relativistic bunch travelling on a prescribed reference trajectory. Here we report on a new CSR model implemented in the General Particle Tracer (GPT) code that avoids most of the usual assumptions: It directly evaluates the Liénard'Wiechert potentials based on the stored history of the beam. It makes no assumptions about reference trajectories, and also takes into account the transverse size of the beam. Example results demonstrating normalised emittance growth in the first bunch compressor of FERMI@Elettra are presented.

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THPAK112

Toward an End-to-End Model for ISAC-I Accelerators

ISAC, rfq, simulation, TRIUMF

3500

O. Shelbaya, O.K. Kester
TRIUMF, Vancouver, Canada

Diurnal-like transmission variations in the ISAC-I warm accelerator system necessitates periodic retuning by operators. While beam loss points are well known, re-tuning nevertheless results in additional downtime and reduced count rates at experiments. This has motivated the development of an end-to-end simulation of the ISAC-I linear accelerator (linac) system to understand and characterize the nature of transmission instabilities spanning several hours to days.

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THPAK153

Linac Optics Correction With Trajectory Scan Data

quadrupole, optics, lattice, storage-ring

3606

X. Huang, Y.-C. Chao, T.J. Maxwell
SLAC, Menlo Park, California, USA
T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

We proposed and tested a scheme to measure and correct linac optics by scanning the beam trajectory in the horizontal and vertical phase spaces. The trajectory data are compared to tracking data in a fitting scheme, from which we can derive the quadrupole strength errors. Simulation is carried out to evaluate the requirements and the performance of the method. The method is experimentally applied to FEL linacs.

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THPAL005

Construction and Commissioning of the S-Band High-Gradient RF Laboratory at IFIC

klystron, network, GUI, cathode

3619

D. Esperante Pereira, C. Blanch Gutiérrez, M. Boronat, J. Fuster, D. Gonzalez Iglesias, A. Vnuchenko
IFIC, Valencia, Spain
N. Catalán Lasheras, G. McMonagle, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
A. Faus-Golfe
LAL, Orsay, France
B. Gimeno
UVEG, Burjasot (Valencia), Spain

An S-Band High-Gradient (HG) Radio Frequency (RF) laboratory is under construction and commissioning at IFIC. The purpose of the laboratory is to perform investigations of high-gradient phenomena and to develop normal-conducting RF technology, with special focus on RF systems for hadron-therapy. The layout of the facility is derived from the scheme of the Xbox-3 test facility at CERN* and uses medium peak-power (7.5 MW) and high repetition rate (400 Hz) klystrons, whose RF output is combined to drive two testing slots to the required power. The design and construction of the various components of the system started in 2016 and has been completed. The installation and commissioning of the laboratory is progressing, with first results expected before mid 2018. The technical characteristics of the different elements of the system and the commissioning status together with preliminary results are described.
* N. Catalan Lasheras, et al., 'Commissioning of Xbox3: a very high capacity X-band RF test stand', Proc. LINAC2016, East Lansing, USA, September 2016.

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THPAL010

Sector DC Dipoles Design for the Beam Test Facility Upgrade

dipole, quadrupole, electron, experiment

3634

A. Vannozzi, S. Lauciani, L. Pellegrino, L. Sabbatini, C. Sanelli, G. Sensolini
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The Beam Test Facility is part of the DAΦNE accelerators system of INFN Frascati National Laboratory. It is a transfer-line optimized for electrons and positrons extracted from the DAΦNE LINAC. An upgrade of the line is scheduled for two purposes: reach a beam energy of 920 MeV (with respect to the actual 750 MeV) and add a new branch to the present transfer line. This new layout foresees six new quadrupoles one fast ramped dipole, two H-shape and one C-shape sector dipoles. The design of the magnets has been completely performed at INFN involving Electromechanical Enterprise partner in the design phase in order to optimise the manufacturing process. This effort lead to a complete set of detailed CAD drawings that can be directly used by manufacturer to build the magnets. The goal is to boost the manufacturing of prototypes and small series from Small and Medium Enterprises. Magnetic measurements will be performed at INFN. This poster is focused on the realization of the two full iron yoke H-shape and C-shape dipoles, respectively with 45 and 15 bending angle. They are characterized by a high flux density of 1.7 T in a gap of 35 mm. They have a bending radius of 1.8 m

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THPAL011

Fast Ramped Dipole and DC Quadrupoles Design for the Beam Test Facility Upgrade

dipole, quadrupole, electron, positron

3638

L. Sabbatini, E. Di Pasquale, L. Pellegrino, C. Sanelli, G. Sensolini
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy
A. Vannozzi
Sapienza University of Rome, Rome, Italy

The Beam Test Facility (BTF) is part of the DAΦNE accelerators system of INFN Frascati National Laboratory. It is a transfer-line optimized for electrons and positrons extracted from the DAΦNE LINAC. An upgrade of the line is planned in order to reach a beam energy of 920 MeV (with respect to the present 750 MeV), adding a new branch to the present transfer line. The design of the magnets for this new layout has been completely performed at INFN, including electromagnetic, mechanical, thermal and hydraulic aspects. This effort lead to a complete set of detailed CAD drawings that can be used by Industrial partners to build the magnets. The manufacturing processes have been studied in detail: the goal is to boost the manufacturing of prototypes and small series from Small and Medium Enterprises. Magnetic measurements will be performed at our Institute. In this report we describe two types of magnets for this project. The first magnet is a C-shape fast ramped dipole, designed for a beam deflection of 15 degrees; the rise time is 100ms, the gap is 25mm with a magnetic field of 1.11 T. The second is a family of seven quadrupoles with a gradient of 20 T/m and a bore of 45mm.

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THPAL012

Soft Chemical Polishing and Surface Analysis of Niobium Samples

cavity, niobium, SRF, operation

3641

J. Conrad, L. Alff, M. Arnold, S. Flege, R. Grewe, M. Major, N. Pietralla
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: Work supported by the German Federal Ministry for Education and Research (BMBF) under Grant No. 05H15RDRBA
The Superconducting Darmstadt Linear Accelerator S-DALINAC uses twelve Niobium Cavities with a RRR of 280 which are operated at 2 K. The operating frequency is 3 GHz; the design value of the accelerating gradient is 5 MV/m. To achieve the target value of 3 x 10˄9 for Q0, different surface preparation methods were applied and systematically tested using a vertical 2 K cryostat. A well-established technique is the so called Darmstadt Soft Chemical Polishing, which consists of an ultrasonic cleaning of the cavity with ultrapure water followed by oxidizing the inner surface with nitric acid. After rinsing with water the niobium oxide layer is removed with hydrofluoric acid in a separate second step. Finally the structure is rinsed and then dried by a nitrogen flow. Until now each cavity in operation was chemically treated with a proven record of success. In order to understand and to optimize the process on the niobium surface, systematic tests with samples were performed and analyzed using material science techniques like SEM, SIMS and EDX. We will report on the results of our research and we will give a review on our experiences with varied chemical procedures.

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THPAL027

Transverse RF Deflecting Structures for the MAX IV LINAC

GUI, polarization, klystron, emittance

3684

D. Olsson, F. Curbis, E. Mansten, S. Thorin, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV LINAC operates both as a full-energy injector for two electron storage rings, and as a driver for a Short Pulse Facility (SPF). A soft X-ray Laser (SXL) beamline will also be installed in the end of the existing LINAC. For SPF and SXL operation, it is important to characterize beam parameters such as bunch profile, slice energy spread and slice emittance. For these measurements, two 3 m long transverse deflecting RF structures with a matching section are being developed. The structures are operating at S-band and have variable polarizations. When fed via a SLED pulse compressor, the two structures can generate a total integrated deflecting voltage higher than 100 MV which is sufficient for measurements with temporal resolutions down to 1 fs. This paper describes the initial RF design of the deflecting structures.

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THPAL030

Vertical Electropolishing of 1.3 GHz Niobium 9-Cell Cavity: Parameter Study and Cavity Performance

cavity, cathode, accumulation, niobium

3695

V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan
H. Ito
Sokendai, Ibaraki, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

VEP parameters and process have been already optimized with single-cell 1.3 GHz niobium cavity at Marui Galva-nizing Company working in collaboration with KEK. A unique cathode called 'Ninja cathode' with an optimized shape was applied to single-cell cavities. The cathode was effective to stop the bubble accumulation in the upper half-cell of the cavity and yielded smooth surface and uniform removal in the cell. This work shows parameter study with the Ninja cathode and a 9-cell coupon cavity which contains totally 9 coupons and viewports in the first, fifth, and ninth cells. Effects of temperature and acid flow in the cathode housing were studied using coupon currents and by observing bubbles through the viewports. The adequate parameters found with 9-cell coupon cavity were applied on a 9-cell cavity to be tested in vertical cryostat. The VEP and vertical test results are reported.

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THPAL034

Dynamic Tuner Development for Medium β Superconducting Elliptical Cavities

cavity, operation, SRF, superconducting-RF

3709

C. Contreras-Martinez, P.N. Ostroumov
FRIB, East Lansing, USA
E. Borissov, S. Cheban, Y.M. Pischalnikov, V.P. Yakovlev, J.C. Yun
Fermilab, Batavia, Illinois, USA

Funding: Work supported by U.S. DOE SCGSR program under contract number DE-SC0014664, Michigan State University, and Fermi Research Alliance under contract N. DEAC02-07CH11959 with the U.S. DOE
The Facility for Rare Isotope Beams (FRIB) is developing a 5-cell 644 MHz β_opt=0.65 elliptical cavity for a future linac energy upgrade to 400 MeV/u for the heaviest uranium ions. Superconducting elliptical cavities operated in continuous wave, such as the ones for FRIB, are prone to microphonics which can excite mechanical modes of the cavities. It has been shown that the detuning due to microphonics can be mitigated with the use of piezo actuators (fast tuner) as opposed to the costly option of increasing the input RF power. The FRIB slow/fast dynamic tuner will be based on the Fermilab experience with similar tuners like those developed for the linac coherent light source (LCLS) II and proton improvement plan (PIP) II. This paper will present the results of tuner properties on the bench.

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THPAL035

Design of β=0.65, 5 Cells, 644 MHz Elliptical Cavity for FRIB Upgrade

cavity, cryomodule, niobium, operation

3712

M. Xu, C. Compton, C. Contreras-Martinez, W. Hartung, S.H. Kim, S.J. Miller, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, A. Taylor, J. Wei, T. Xu, Q. Zhao
FRIB, East Lansing, USA
I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the U.S. DOE Office of Science under Cooperative Agreement DE-SC0000661 and the NSF under Cooperative Agreement PHY-1102511, the State of Michigan and Michigan State University.
The superconducting (SC) linac of the Facility for Rare Isotope Beams (FRIB) under construction will deliver 200 MeV/u, 400 kW beam to the target for producing rare isotopes at Michigan State of University (MSU). For further beam energy upgrade, we have designed the β = 0.65, 5 cells, 644 MHz elliptical cavity. The beam energy can be upgraded to 400 MeV/u by installing 11 cryomodules to the available space in the FRIB tunnel.

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THPAL041

Power Coupler Design for the LUCRECE Project

cavity, simulation, SRF, coupling

3732

H. Guler, D. Auguste, J. Bonis, O. Bouras, M. El Khaldi, W. Kaabi, P. Lepercq
LAL, Orsay, France

The LUCRECE project aims at developing an elementary RF system (cavity, power source, LLRF and controls) suitable for continuous (CW) operation at 1.3 GHz. This effort is made in the framework of the advanced and compact FEL project LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation), using superconducting linac technology for high repetition rate and multi-user operation (www.lunex5.com). In this context, based on its large experience on coupler design and RF conditioning, LAL Laboratory is in charge of the design and the fabrication of RF couplers that could operate at up to 15-20 kW in CW mode. For this purpose, geometry based on CORNELL 65kW CW couplers will me modified to fulfil the LCLS2 type cavity with the high necessary coupling level. Electromagnetic simulations and optimisation and associated thermal heating will be discussed. Methods to decrease the thermal impact, and strategy for RF conditioning will be considered.

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THPAL053

Perveance Measurement of the TLS-Linac Klystron and the Evaluation of Its Operation Performance

klystron, electron, operation, cathode

3763

H.H. Chen, C.H. Kuo, K.-K. Lin, Y.-H. Liu
NSRRC, Hsinchu, Taiwan

The high power klystron is a radio frequency amplifier for TLS linac operation. It is a crucial device for electron acceleration in linac. How to evaluate its efficiency, lifetime and performance of klystron in operation is one of the major concern in this report. The key klystron parameter perveance is introduced and used for performance evaluation and operation status monitoring. It is important to execute periodic monitoring on perveance for ensuring a stable linac operation. Klystron characteristics diagnostics can be achieved through perveance measurement. A couple of klystron diagnostic parameters concerning perveance are explored for field examination purpose. Perveance comparison with factory acceptance test data is also presented.

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THPAL081

A 3 GHz SRF Reduced-beta Cavity for the S-DALINAC

cavity, SRF, operation, electron

3838

D.B. Bazyl, H. De Gersem, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany
J. Enders, S. Weih
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through GRK 2128
In order to reduce the energy spread and to be able to use a 200 keV spin-polarized electron source, the initial part of the injector linac of the superconducting Darmstadt electron linear accelerator S-DALINAC needs to be upgraded. The decisions on the cavity type, number of cells and value of geometric beta are motivated. The main part of this work is dedicated to the mechanical design of the cavity. A precise evaluation of the mechanical characteristics of an SRF cavity is necessary during the design stage. The dependence of the resonant frequency of the fundamental mode on external mechanical loads needs to be investigated for developing the tuning procedures. The results of the multiphysics simulations and of the optimization of the mechanical design are presented.

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THPAL085

High Power RF Conditioning on CLARA

cavity, vacuum, solenoid, multipactoring

3852

L.S. Cowie, D.J. Scott
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt, W.L. Millar
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

The CLARA accelerator at Daresbury Laboratory will have 8 normal conducting RF cavities. Automating the high power RF conditioning of these cavities will mean a repeatable, research-lead process is followed. An auto-mated algorithm has been written in Python. A prototype algorithm was used to condition the first CLARA travel-ling wave linac in October 2017. The linac was success-fully conditioned over approximately 12 million pulses up to 27 MW for a 750 ns pulse. A more complex and robust algorithm was used to re-condition the standing wave 10 Hz photoinjector after a cathode change. The photoinjec-tor was conditioned to 10 MW for a 2.5 μs pulse in Feb-ruary 2018 over 2.1 million pulses. Conditioning method; differences for travelling and standing wave structures; difficulties and interesting phenomena are all discussed.

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THPAL101

Longitudinal Effects of Trapped Homs in Shanghai Coherent Light Facility

cavity, HOM, impedance, FEL

3872

J.J. Guo, Q. Gu, H.T. Hou, J.H. Tan, M. Zhang
SINAP, Shanghai, People's Republic of China

Funding: Shanghai Institute of Applied Physics, Chinese Academy of Sciences
Shanghai Coherent Light Facility (SCLF), a superconducting accelerated structure-baesd FEL device, is now under development at Shanghai Institute of Applied Physics, Chinese Academy of Sciences. We investigate effects of cryogenic losses caused by trapped longitudinal high order modes (HOM). Results of calculations are presented for losses caused by HOMs excitation in the acceleration RF system of the continues-wave (CW) linac of SCLF.

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THPAL110

High-Power RF Test of Coaxial Couplers for the Injection Linac of XiPAF

cavity, vacuum, multipactoring, coupling

3899

Y. Lei, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
J. Jiang, H. Li, C. Yu
Beijing Aerospace Guagntong Technology Co., Beijing, People's Republic of China

For the high-power RF test of the coaxial couplers which will be employed on the linac injector of the XiPAF (Xi'an Proton Application Facility) project, a high-power conditioning cavity was designed and manufactured [1]. There are some optimized aspects on the cavity and couplers to obtain better RF performance during the high-power testing process. The traveling-wave test and full-power-reflection test were executed to check whether the coupler can afford the enough power level for the linac operation, and whether only one coupler can afford the total power for the RFQ. The construction of the testing stand, optimization of RF parameters and results of high-power RF test are presented in this paper.

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THPAL113

The Design of 1 MeV Proton LINAC Operating in CW

cavity, proton, simulation, resonance

3905

N.V. Avreline
TRIUMF, Vancouver, Canada

Experimental results and computer simulations of electrodynamic and thermodynamic characteristics are presented for an accelerating structure that is excited in the TM010 mode and that has the accelerating channel of URAN-1M located in the diametric plane. The idea of using this structure in the particle accelerator URAN-1M, located at the Baikov Institute of Metallurgy and Materials Science, with the goal of increasing the average beam current is explored.

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THPAL121

The Operational Experience of E-Linac Cryogenic System at TRIUMF

cryogenics, cryomodule, MMI, operation

3928

R.R. Nagimov, Y. Bylinskii, D. Kishi, S.R. Koscielniak, A.N. Koveshnikov, R.E. Laxdal, D. Yosifov
TRIUMF, Vancouver, Canada

Funding: ARIEL is funded by CFI, the Provinces of AB, BC, MA, ON, QC, and TRIUMF. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.
The new Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Rare Isotope Beams (RIB) facility at TRIUMF. Superconducting radio-frequency (SRF) cavities cooled down to 2 K are the key part of ARIEL electron linear accelerator (e-linac). Design of the cryogenic system was bound to follow both phased project schedule and existing building infrastructure. Due to the scheduling of commissioning and R&D activities of ARIEL project, high availability requirements were set for e-linac cryogenic system during its commissioning stage. Various upgrades were introduced during system commissioning in order to improve overall availability and reliability of the system. This paper presents the details of operational experience, commissioning activities and continuous improvement of various operational aspects of e-linac cryogenic system.

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THPAL123

Fabrication and Test of β=0.3 325MHz Balloon Single Spoke Resonator

cavity, multipactoring, niobium, TRIUMF

3934

Z.Y. Yao, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, H.L. Liu, Y. Ma, B. Matheson, B.S. Waraich, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

A novel balloon variant of the single spoke resonator (SSR) has been designed, fabricated and tested at TRIUMF. The cavity is the β=0.3 325 MHz SSR1 prototype for the Rare Isotope Science Project (RISP) in Korea. The balloon variant is specifically designed to reduce the likelihood of multipacting barriers near the operating point. A systematic multipacting study led to a novel geometry, a spherical cavity with re-entrant irises plus a spoke. The balloon cavity provides competitive RF parameters and a robust mechanical structure. Cold tests demonstrated the principle of the balloon concept. The fabrication experience and the preliminary test results will be reported in this paper.

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THPAL126

Nitrogen Bake-out Procedures at the Vertical High-Temperature UHV-Furnace of the S-DALINAC

cavity, SRF, vacuum, niobium

3937

R. Grewe, L. Alff, M. Arnold, J. Conrad, S. Flege, M. Major, N. Pietralla
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: Work supported by the Federal Ministry of Education and Research through grant No. 05H15RDRBA.
As the performance limits of bulk Nb srf cavities are reached, our research is focused on materials with superior srf properties like Nb3Sn and NbN. Research on NbN resulted in the "nitrogen-doping" process used for increasing the quality factors of srf cavities for the LCLS-II project. This process leads to delta-phase Nb-N, a phase with higher critical sc parameters than bulk Nb. This phase is formed at temperatures of 800°C in nitrogen atmospheres of 10^-2 mbar. Other crystalline phases of NbN have even better sc parameters. We concentrate our research on applicability of delta-phase NbN for cavities. The delta-phase forms at temperatures of above 1300°C, which is more than most of the furnaces at accelerator facilites are capable of. Since 2005 the Institute for Nuclear Physics at the Technische Universität Darmstadt operates a high temperature vacuum furnace which has been upgraded to allow temperatures of up to 1750°C and bakeouts of niobium samples and cavities in nitrogen atmospheres. We will report on the current status of our research on nitrogen bake-out procedures on Nb samples. The samples have been analyzed at the Material Science Departement with SIMS, REM and XRD.

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THPAL140

Rework Recipe Development, Analysis and Results of Select 9-Cell Cavities for LCLS-II

cavity, embedded, niobium, site

3968

A.D. Palczewski, K. Macha, H. Park, C.E. Reece, K.M. Wilson
JLab, Newport News, Virginia, USA
A. Burrill, D. Gonnella
SLAC, Menlo Park, California, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The SLAC National Accelerator Laboratory is currently constructing a major upgrade to its accelerator, the Linac Coherent Light Source II (LCLS-II). Several Department of Energy laboratories, including the Thomas Jefferson National Accelerator Facility (JLab) and Fermi National Accelerator Laboratory (FNAL), are collaborating in this project. The cryomodules for this project each consist of eight 1.3-GHz cavities produced by two vendors, Research Instruments GmbH in Germany (RI*) and Ettore Zanon S.p.a. in Italy (EZ*), using niobium cell material from Tokyo Denkai Co., Ltd. (TD) and Ningxia Orient Tantalum Industry Co., Ltd. (OTIC/NX)). During the initial production run, cavity performance from one of the vendors (Vendor A) was far below expectation. All the cavities had low Q0, later attributed to minimal EP as well as high-flux-trapping NX material, early quench behaviour below 18 MV/m, with many having Q0 roll-off at 12-16 MV/m. Production was stopped multiple times over the following 6 months, with test batches of cavities being made to ascertain the root cause of the problem. The final root cause of the problem was found to be inappropriate grinding of the RF surface prior to welding which left normal conducting inclusions in the surface. In addition, most cavities showed internal and external weld spatter which required post weld grinding and a very rough surface from operating the electropolishing machine in an etching rather than polishing regime. All issues have been corrected on new cavities and rework is underway on the originally effected cavities.

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THPAL149

RF System Based on Two Klystrons and Phase Modulation for Photo-Cathode Injector

gun, klystron, experiment, cathode

3996

P. Wang, D.Z. Cao, H.B. Chen, J. Shi, Z.H. Wang, H. Zha
TUB, Beijing, People's Republic of China

We proposed an RF system with two klystrons, of which the powers are combined by a 3dB-hybrid. By managing the phases of the two klystrons respectively, the two pulses from the two output ports of the 3dB-hybrid can be of different powers, phases, and shapes. One of the two pulses can be set to an RF gun, while the other one can feed traveling accelerating structures. Two methods of phase modulation were proposed based on this scheme. Comparing with the state-of-art RF system, the new one can be of high efficiency or can generate electron beams with higher energy. The detailed analysis of the two methods and some experiments are described in this paper.

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THPAL156

High-Power Test of a Compact X-Band RF Rotary Joint

GUI, network, cathode, electromagnetic-fields

4017

J. Liu, H.B. Chen, J.Q. Qiu, J. Shi, Z.H. Wang, X.W. Wu, H. Zha
TUB, Beijing, People's Republic of China

A compact X-band (9.3 GHz) RF rotary joint has been developed in the accelerator laboratory of Tsinghua University. Cold measurements on the rotary joint using Vector-Network showed good results. In recent high-power tests, the RF rotary joint was operated under a 1.6 MW X-band magnetron. The incident power, the transmitted power and the pulse width of this rotary joint have been measured. The transmitted power kept stable in different rotation angle. In this paper, the setup and results of the high-power tests of this RF rotary joint are presented.

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THPAL157

Investigation of Transverse Wakefield and Beam Break Up Effect in Irradiation Linacs

cavity, wakefield, experiment, simulation

4020

X.C. Meng, H.B. Chen, J. Shi, Z.H. Wang, H. Zha, S.X. Zheng
TUB, Beijing, People's Republic of China
G.H. Li, J.S. Liu, Y.H. Liu
NUCTECH, Beijing, People's Republic of China

Study of beam break up effect in linacs has been done in recent years. The beam-induced high order dipolar modes, especially the TM11-like mode were investigated for the linacs both in travelling wave and backward trav-elling wave. Measurements of beam-break up in a travel-ling wave linac were carried out and results are discussed. Moreover, a theoretical model was developed for the irradiation linacs to study the detailed interaction be-tween the transverse wakefield and the electron beam.

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THPMF001

Beam Dynamics Studies for Beam Focusing and Solenoid Alignment at SINBAD

solenoid, alignment, emittance, gun

4026

S. Yamin, R.W. Aßmann, B. Marchetti, J. Zhu
DESY, Hamburg, Germany

SINBAD (Short INnovative Bunches and Accelerators at DESY) facility under construction at DESY plans to host several experiments for the production of ultra-short bunches and will be a test facility for high-gradient compact novel acceleration techniques. The ARES (Accelerator Research Experiment at SINBAD) linac is foreseen to produce ultra-short bunches to be injected e.g. into Novel Dielectric Laser Acceleration structures or Laser Wake-Field Acceleration experiments. The work presented in this paper is based on optimization of the focusing system consisting of solenoids for the ARES, which have been studied earlier in detail but is revisited for updated beamline. Moreover tolerances for the possible misalignment of solenoids are presented investigating the effect on the beam properties during the gun commissioning.
* J. Zhu, R. Assmann, U. Dorda, B. Marchetti, "Matching sub-fs electron bunches for laser-driven plasma acceleration at SINBAD", Nucl. Instrum. Methods Phys. Res., Sect. A 829, 229 (2016)

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THPMF025

Emittance Measurements at FAST Facility

emittance, MMI, electron, controls

4100

J. Ruan, D.R. Broemmelsiek, D.J. Crawford, A.L. Edelen, J.P. Edelen, D.R. Edstrom, A.H. Lumpkin, P. Piot, A.L. Romanov, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

Funding: *Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The FAST facility at Fermilab recently been commissioned has demonstrated the generation of electron beam within a wide range of parameter (energy, charge) suitable for accelerator-science and beam-physics experiments. This accelerator consists of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. It will mainly serve as injector for the upcoming Integrable Optical Test Accelerator (IOTA). At the same time we will also carry out a LINAC based intense gamma ray experiment based on the Inverse Compton scattering. It is essential to understand the beam emittance for both experiments. A number of techniques are used to characaterizing the beam emittance including slit based method and quad scan method. An on-line emittance measurement based on multi-slit method is developed so the emittance measured will be immediately available to support further beam optimization. In this report we will present the results from the emittance studies using this tool. We will also present the emittance measurement based on quads scan technique for the high energy beam line.

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THPMF045

Synchronized Beam Position Measurement for SuperKEKB Injector Linac

controls, electron, EPICS, operation

4159

M. Satoh, F. Miyahara, T. Suwada
KEK, Ibaraki, Japan
T. Kudou, S. Kusano
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
T. Ohfusa, H.S. Saotome, M. Takagi
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan

Toward SuperKEKB project, the injector linac upgrade is ongoing for aiming at the stable beam operation with low emittance and high intensity bunch charge. One of the key challenges is a low emittance preservation of electron beam because the vertical emittance of 20 mm.mrad or less should be transported to the main ring without a damping ring. For this purpose, the fine alignment of accelerator components is a crucial issue since the linac alignment was badly damaged by the big earthquake in 2011. From the simulation results of emittance growth, the alignment of the quadrupole magnets and accelerating structures should be conducted at the level of 300 um in rms along the 600-m-long linac. In addition, we are aiming at the level of 100 um alignment in rms within the short range distance of 100 m long. Even after the fine component alignment can be achieved, the fine beam orbit manipulation is necessary for low emittance preservation. For these reasons, we have developed the new BPM readout system based on VME64x. The new system has improved the precision of beam position measurement up to 3 um from 25 um. We will describe the software development of the new BPM readout system.

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THPMF063

The MESA 15 kW cw 1.3 GHz Solid State Power Amplifier Prototype

operation, experiment, SRF, cavity

4216

R.G. Heine, F. Fichtner
IKP, Mainz, Germany

The Mainz Energy recovering Superconducting Accelerator MESA is a multi-turn energy recovery linac with beam energies in the 100 MeV regime currently designed and build at Institut für Kernphysik (KPH) of Johannes Gutenberg-Universität Mainz. The main accelerator consists of two superconducting Rossendorf type modules, while the injector MAMBO (MilliAMpere BOoster) relies on normal conducting technolgy. The high power RF system is planned completely in solid state technology. With the high power demands of the normal conducting RF cavities up-to-date transistor technology with increased power density has to be used. A 15 kW CW power ampifier prototype with the new technology has been developed by Sigma Phi Electronics and deliverd to KPH. In this paper we will present the results of the performance measurements of the amplifier.

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THPMF064

Beam Based Alignment of SRF Cavities in an Electron Injector Linac

cavity, alignment, emittance, electron

4219

F. Hug
KPH, Mainz, Germany
M. Arnold, T. Bahlo, J. Pforr, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Funded by DFG through Cluster of Excellence EXC 1098/2014 "PRISMA" and RTG 2128 "AccelencE" and by the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No 730871
Proper alignment of accelerating cavities is an important issue concerning beam quality of accelerators. In particular SRF cavities of injector linacs using high accelerating gradients on low beta electron beams can affect the beam quality significantly when not aligned perfectly. On the other hand knowing the exact position of every cavity after several cool-down cycles of a cryomodule can be difficult depending on the cryomodule design. We will report on operational experience on the SC injector of the Darmstadt superconducting linac and ERL (S-DALINAC) showing unexpected effects on beam dynamics and beam quality. Operators could observe transverse beam deflections by changing accelerating phases of the injector SRF-cavities while a growth of tranverse emittance occurred at the same time. As beam currents in the S-DALINAC injector do never exceed 100 μA and the effects could even be observed at nA beam currents space-charge effects could be eliminated to be the reason for these observations. In this work we will report on the possibility to align SRF cavities after cooldown by measuring the transverse deflection of the beam and compare results with beam dynamics simulations.

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THPMF082

Suppression of Microbunching Instability Using a Quadrupole Inserted Chicane in Free-Electron-Laser Linacs

bunching, electron, laser, FEL

4267

B. Li, J. Qiang
LBNL, Berkeley, California, USA

The microbunching instability (MBI) driven by beam collective effects in a linear accelerator of a free-electron laser (FEL) facility can significantly degrade the electron beam quality and FEL performance. A method exploited longitudinal mixing derived from the natural transverse spread of the beam was proposed several years ago using two dipoles to suppress the instability. In this paper, instead of using bending magnets to introduce the transverse-to-longitudinal coupling, which will lead to an inconvenient deflection of the downstream beam line, we propose a scheme using a quadrupole inserted chicane to introduce the longitudinal mixing inside the accelerator transport system to suppress this instability. And we finally eliminate the transverse-to-longitudinal coupling after the dogleg section.

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THPMF090

Linac Design Elements for Spaceborne Accelerators

cavity, operation, electron, dipole

4291

J.W. Lewellen, C.E. Buechler, G.E. Dale, M.A. Holloway, D.C. Nguyen, D. Patrick
LANL, Los Alamos, New Mexico, USA
V.A. Dolgashev, E.N. Jongewaard, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
J-.M. Lauenstein
NASA Goddard Space Flight Center, Greenbelt, USA

Funding: Los Alamos National Laboratory LDRD and Program Development
Los Alamos National Laboratory, in collaboration with SLAC and Goddard Space Flight Center, have begun developing a high-duty-factor, MeV-range linear accelerator intended for use on satellites, specifically to probe the magnetosphere-ionosphere linkage. The design makes use of low-beta C-band cavities operating at moderate gradients, individually powered by 500-W RF amplifier chips. We present the current state of the design, and technology maturation efforts including RF amplifier performance studies, cavity tuner design and an initial acceleration test using a DC beam source and single RF cavity.

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THPMK001

Creating Two-Pulse Beams from a Photoinjector for Two Color FEL or Beam Driven PWFA Experiments

gun, emittance, simulation, cathode

4294

J. Andersson, J. Björklund Svensson, M. Kotur, F. Lindau, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV linac is investigated as a FEL driver in the SXL project, but there is also an ongoing investigation in using the linac as a driver for beam driven plasma wakefield acceleration experiments. From both these applications, double pulses from the photoinjector within the same RF period is desired. In this paper we discuss the possibilities of using the current photoinjector at MAX IV as driver and show simulations results from the pre-injector, both for FEL applications and for PWFA applications.

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THPMK002

The Pre-Injector Design for the MAX IV SXL

gun, cathode, emittance, laser

4297

J. Andersson, M. Kotur, D. Kumbaro, F. Lindau, E. Mansten, D. Olsson, L.K. Roslund, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

In this paper we present the current status of the design for the pre-injector (photo-cathode gun, solenoid and first linac) for the SXL project at MAX IV. The SXL project requires a higher repetition rate and since improved beam quality compared to what the current photo-cathode gun can operate at is needed, a new photo-cathode gun will be manufactured. We briefly describe the components of the pre-injector, followed by the design of the new photo-cathode gun. The design is similar to the old gun but with a new RF cavity using elliptical irises and racetrack profile main cell. The current parameters for the next gun to be manufactured are discussed, and some simulations and expected beam quality from the injector are shown.

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THPMK016

Simulation Study of the NSRRC High Brightness Linac System and Free Electron Laser

FEL, undulator, simulation, electron

4329

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

A 263 MeV linac system has been designed to provide a high brightness electron beam for the NSRRC VUV FEL test facility. This system is equipped with a dogleg with linearization optics to compensate the effects of nonlinear energy chirps introduced into the system by the chirper linac voltage during bunch compression. In this study, we performed start-to-end simulation to illustrate the capability of this linac system to generate a beam that can be used to drive a SASE FEL to saturation within reasonable undulator length. It has been demonstrated that, for a 200 pC beam, such FEL has a saturated output power of ~200 MW at 6-m undulator length. Further optimization of bunch current profile and momentum spectrum is required.

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THPMK017

Experimental Study of Coherent THz Sources Driven by the NSRRC High Brightness Photo-injector

radiation, electron, undulator, bunching

4332

M.C. Chou, K.T. Hsu, N.Y. Huang, J.-Y. Hwang, W.K. Lau, A.P. Lee, C.C. Liang, G.-H. Luo
NSRRC, Hsinchu, Taiwan

Accelerator-based coherent THz radiation sources are being studied with the NSRRC high brightness photoinjector which has been installed in the Accelerator Test Area (ATA) recently. This injector is equipped with a laser-driven photocathode rf gun and a 5.2-m long S-band traveling-wave linac for beam acceleration. A few tens MeV, ultrashort bunches of ~100 fs bunch length can be produced from the injector by velocity bunching technique. Tunable narrow-band THz coherent undulator radiation (CUR) can be generated from a U100 planar undulator when it is driven by such beam. One the other hand, broadband THz coherent transition radiation (CTR) generated by passing this beam through a metallic foil is used for determination of bunch length by autocorrelation technique. The experimental setup and results are presented in this paper.

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THPMK019

Generation of Tunable Femtosecond X-Rays from High-Period-Number Resonant Transition Radiation Emitters

radiation, electron, photon, bunching

4339

P. Wang, K.C. Leou
NTHU, Hsinchu, Taiwan
M.C. Chou, J.-Y. Hwang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
C.T. Lee
ITRC, Hsinchu, Taiwan

Funding: Work supported by the Ministry of Science and Technology, ROC (Taiwan).
Femtosecond resonant transition radiation (RTR) in x-ray region can be generated from alternatively stacked multilayer structures when they are driven by relativistic ultrashort electron beams. These structures can be fabricated by coating layer pairs of high and low density materials. By increasing the number of these layer pairs, narrow-band x-ray can be generated. In this report, we present our efforts on the development of a 12 keV femtosecond narrow-band x-ray source by driving high-period-number RTR emitters with the NSRRC photoinjector linac system. Radiation wavelength is tunable by varying the incident angle of the beam. A few tens MeV, ultrashort beam has been available from the photoinjector system via velocity bunching in the rf linac. A 100-period (200 layers) Mo/Si multi-layer emitters with thin substrate have been fabricated. For a 100 pC drive beam, the expected photon yield from such emitter is about 4x104.

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THPMK043

Timing Stability at LCLS

timing, cavity, laser, FEL

4381

F.-J. Decker, R.N. Coffee, W.S. Colocho, J.M. Glownia, K. Gumerlock, B.L. Hill, T.J. Maxwell, J. May
SLAC, Menlo Park, California, USA

The beam stability of the LCLS (Linac Coherent Light Source) has increased substantially over the years. Transversely it is a fraction of the beam size. The energy jitter was reduced from five times the energy spread to a fraction of it. Only the timing jitter is left. It got improved during the energy jitter reduction, but typically left alone. So we have five dimensions of the six-dimensional phase space covered with feedbacks and special 60-Hz jitter setups which eliminate the difference between every other pulse, but not for the general timing setup. We describe a scheme with the RF of the XTCAV, which could be used for other setups like lasers.

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THPMK058

RF Design of the X-band Linac for the EuPRAXIA@SPARC_LAB Project

klystron, booster, electron, GUI

4422

M. Diomede
Sapienza University of Rome, Rome, Italy
D. Alesini, M. Bellaveglia, B. Buonomo, F. Cardelli, E. Chiadroni, G. Di Raddo, R.D. Di Raddo, M. Diomede, M. Ferrario, A. Gallo, A. Ghigo, A. Giribono, V.L. Lollo, L. Piersanti, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
N. Catalán Lasheras, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland

We illustrate the RF design of the X-band linac for the upgrade of the SPARC_LAB facility at INFN-LNF (EuPRAXIA@SPARC_LAB). The structures are travelling wave (TW) cavities, working on the 2π/3 mode, fed by klystrons with pulse compressor systems. The tapering of the cells along the structure and the cell profiles have been optimized to maximize the effective shunt impedance keeping under control the maximum value of the modified Poynting vector, while the couplers have been designed to have a symmetric feeding and a reduced pulsed heating. In the paper we also present the RF power distribution layout of the accelerating module and a preliminary mechanical design.

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THPMK064

RF System for SXFEL: C-band, X-band and S-band

FEL, klystron, operation, LLRF

4446

W. Fang, Q. Gu, X.X. Huang, L. Li, Z.B. Li, J.H. Tan, C.C. Xiao, J.Q. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Shanghai Soft X-ray FEL facility is under commissioning now, which linac is compased of one S-band injector, C-band main linac and X-band linearizer. In SXFEL S-band injector could provide 200MeV beam energy based on 4 RF power unit, and then 6 C-band RF units boost beam energy to 840MeV based on 33MV/m at least, which will be ramped to 40MV/m in the ungrading. In the middle of S-band and C-band RF system, a X-band RF unit is used as linearizer to make energy spread of electron beam linear distribution, which is important for bunch compressor and FEL radiation. In this paper, details of RF system design and status of SXFEL is introduced, and some operation results are presented.

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THPMK069

Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai

FEL, undulator, dipole, kicker

4456

S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang
SINAP, Shanghai, People's Republic of China

A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.

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THPMK076

Longitudinal Shaping for Beam-Driven Plasma Wakefield Accelerators

electron, FEL, plasma, simulation

4477

Z. Wang, K.Q. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
S. Huang, W. Lu
TUB, Beijing, People's Republic of China

The generation of high quality driven electron beam (high peak current and small beam size) is quite important for the beam-driven plasma accelerator. Besides, a linearly ramped, more exactly, the triangular current distribution is more suitable. In this paper, by adjusting the phase and the amplitude of the harmonic linearizer, the linear ramped current distribution electron beam is generated by the FEL linac. The CSR introduced emittance growth and the jitters of the electron are researched. The electron beam generated by the ramped driven beam in the plasma is researched as well.

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THPMK078

Corrugated Structure as a Linearizer in High Repetition Rate X-Ray Free Electron Laser Source

electron, FEL, laser, simulation

4485

Z. Wang, C. Feng, D. Huang, K.Q. Zhang, M. Zhang
SINAP, Shanghai, People's Republic of China

A feasible method is proposed to compensate the high order mode (HOM) of the RF field, linearize the bunch compression process in the high repetition rate x-ray free electron laser source. In the proposed scheme, the corrugated structure is used in the superconducting linac to linearize the longitudinal phase space of the electron beam. The results show that the peak current of the electron beam will be increased from about 1 kA to over 2 kA with the charge of 100 pC.

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THPMK084

E-field Measurement of 9.3 GHz RF cavity for 6 MeV LINAC

cavity, electromagnetic-fields, electron, hardware

4496

D.H. Ha, J.-S. Chai, M. Ghergherehchi, H.S. Kim, J.C. Lee, H. Namgoong, J.H. Seo, Shin, S.W. Shin
SKKU, Suwon, Republic of Korea

In order to achieve performance close to the design value, fabricated cavity was tuned at Sunkyunkwan university. Tuning was done in two step: each cell tuning and bead-pull system. Each cell tuning was used to determine the status of each cell and to remove the stop-band. Bead-pull system was used to measure the E-field distribution and obtain the required field flatness. This paper describes each cell measurement data and bead-pull measurement system and data.
x-band, linac, measurement

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THPMK087

Conceptual Design of the RF System for the Storage Ring and Linac of the New Light Source in Thailand

cavity, storage-ring, acceleration, operation

4505

N. Juntong, T. Chanwattana, K. Kittimanapun, T. Pulampong, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand

The new light source facility in Thailand will be a ring-based light source with the circumference of approximately 300m and an electron energy of 3GeV. The target beam emittance is below 1.0 nm·rad with a maximum beam current of 300mA. The injector utilizes a full energy C-band linac with a photocathode RF electron gun. The storage ring RF system is based on a 500MHz frequency. The EU-HOM damped cavity and the new SPring-8 design TM020 cavity is the choice of the storage ring cavity. The RF power unit for storage ring can either be a high-power klystron feeding all RF cavities or a combination of low power IOTs or solid-state amplifiers feeding each cavity. The high gradient C-band structure is considered as the main accelerating structure for linac. The RF power system for linac will base on klystron and a modular modulator. Details of RF systems options for this new light source project will be presented.

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THPMK090

First RF Test Results of Two-Cavities Accelerating Cryomodule for ARIEL eLinac at TRIUMF

cavity, cryomodule, TRIUMF, pick-up

4512

Y. Ma, Z.T. Ang, K. Fong, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, R.R. Nagimov, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada

The Advanced Rare Isotope Laboratory (ARIEL) pro-ject requires a 50 MeV, 10 mA continuous-wave (CW) electron linear accelerator (e-Linac) as a driver accelera-tor. Now the stage of the 30MeV portion of the e-Linac is under commissioning which includes an injector cry-omodule(ICM) and the 1st accelerator cryomodules (ACM1) with two cavities configuration. A single 290kW klystron is used to feed the two ACM1 cavities in vector sum closed-loop control. In this paper the initial commis-sioning results of the ACM1 RF system will be present.

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THPMK096

Tuners Alignment on Two 9-Cell Cavities with Single Amplifier under Self-Excited Loop

cavity, TRIUMF, detector, cryomodule

4527

K. Fong, Z.T. Ang, M.P. Laverty, Q. Zheng
TRIUMF, Vancouver, Canada

The TRIUMF eLinac ACM consists of two 9-cell cavities which are driven by a single klystron. The output power from the klystron are split by a variable power divider and send down 2 independently phase adjustable transmission lines to their respective cryomodules. The vector sum of the fields from both cryomodules is used for phase-locked self-excited loop regulation. A semi-automatic procedure to tune the 2 cyromodules to provide the correct amplitudes and phases for self-excitation as well as beam acceleration is described.

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THPMK101

Inverted Geometry Photo-Electron Gun Research and Development at TU Darmstadt

cathode, gun, electron, operation

4545

M. Herbert, J. Enders, Y. Fritzsche, N. Kurichiyanil, V. Wende
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by the Deutsche Forschungsgemeinschaft through GRK 2128 'AccelencE'
The Institute for nuclear physics at TU Darmstadt houses the Superconducting Darmstadt Linear Accelerator S-DALINAC. A photo-electron gun using GaAs photocathodes to provide pulsed and/or polarized electron beams, the S-DALINAC Polarized Injector SPIn, has been installed * for future nuclear-structure investigations**. In order to conduct research and development for this source, a test facility for Photo-Cathode Activation, Test and Cleaning using atomic-Hydrogen (Photo-CATCH) has been constructed***. This setup provides several chambers for photocathode handling and a 60 keV beamline for photo-gun design studies****. Currently, an upgraded inverted insulator geometry is under investigation for Photo-CATCH that is supposed to be implemented at SPIn. We will present the current developments at Photo-CATCH and future measurements.
* Y. Poltoratska et al., J. Phys.: Conf. Series 298 (2011)
** J. Enders, AIP Conf. Proc. 1563, 223 (2013)
*** M. Espig, Diss., TU Darmstadt (2016)
**** N. Kurichiyanil, Diss., TU Darmstadt (2016)

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THPMK103

Initial Testing of Techniques for Large Scale Rf Conditioning for the Compact Linear Collider

operation, linear-collider, ECR, collider

4548

T.G. Lucas, M.J. Boland, P.J. Giansiracusa, R.P. Rassool, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
N. Catalán Lasheras, A. Grudiev, T. Lefèvre, G. McMonagle, I. Syratchev, B.J. Woolley, W. Wuensch, V. del Pozo Romano
CERN, Geneva, Switzerland
J. Paszkiewicz
University of Oxford, Oxford, United Kingdom
C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Vnuchenko
IFIC, Valencia, Spain
R. Zennaro
PSI, Villigen PSI, Switzerland

Nominal operating conditions for the Compact Linear Collider (CLIC) 380 GeV requires 72 MV/m loaded accelerating gradients for a 180 ns flat-top pulse. Achieving this requires extensive RF conditioning which past tests have demonstrated can take several months per structure, when conditioned at the nominal repetition rate of 50 Hz. At CERN there are three individual X-band test stands currently operational, testing up to 6 structures concurrently. For CLIC's 380 GeV design, 28,000 accelerating structures will make up the main linac. For a large scale conditioning programme, it is important to understand the RF conditioning process and to optimise the time taken for conditioning. In this paper, we review recent X-band testing results from CERN's test stands. With these results we investigate how to optimise the conditioning process and demonstrate the feasibility of pre-conditioning the structures at a higher repetition rate before installation into the main linac.

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THPMK105

PERLE - Lattice Design and Beam Dynamics Studies

bunching, lattice, injection, electron

4556

S.A. Bogacz, D. Douglas, F.E. Hannon, A. Hutton, F. Marhauser, R.A. Rimmer, Y. Roblin, C. Tennant
JLab, Newport News, Virginia, USA
D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G. Arduini, O.S. Brüning, R. Calaga, K.M. Dr. Schirm, F. Gerigk, B.J. Holzer, E. Jensen, A. Milanese, E. Montesinos, D. Pellegrini, P.A. Thonet, A. Valloni
CERN, Geneva, Switzerland
S. Bousson, D. Longuevergne, G. Olivier, G. Olry
IPN, Orsay, France
I. Chaikovska, W. Kaabi, A. Stocchi, C. Vallerand
LAL, Orsay, France
B. Hounsell, M. Klein, U.K. Klein, P. Kostka, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
E.B. Levichev, Yu.A. Pupkov
BINP SB RAS, Novosibirsk, Russia

Funding: Work has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
PERLE (Powerful ERL for Experiments) is a novel ERL test facility, initially proposed to validate choices for a 60 GeV ERL foreseen in the design of the LHeC and the FCC-eh. Its main thrust is to probe high current, CW, multi-pass operation with superconducting cavities at 802 MHz (and perhaps testing other frequencies of interest). With very high virtual beam power (~ 10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERL design; becoming a ‘stepping stone' between present state-of-art 1 MW ERLs and future 100 MW scale applications. PERLE design features Flexible Momentum Compaction lattice architecture for six vertically stacked return arcs and a high-current, 6 MeV, photo-injector. With only one pair of 4 cavity cryomodules, 400 MeV beam energy can be reached in 3 re-circulation passes, with beam currents in excess of 15 mA. The beam is decelerated in 3 consecutive passes back to the injection energy, transferring virtually stored energy back to the RF. This unique facility will serve as a test-bed for high current ERL technologies, as well as a user facility in low energy electron and photon physics.

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THPMK106

Architectural Considerations for Recirculated and Energy-Recovered Hard XFEL Drivers

FEL, recirculation, SRF, operation

4560

D. Douglas, S.V. Benson, T. Powers, Y. Roblin, T. Satogata, C. Tennant
JLab, Newport News, Virginia, USA
D. Angal-Kalinin, N. Thompson, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.K. Charles
CERN, Geneva, Switzerland
R.C. York
FRIB, East Lansing, Michigan, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A confluence of events motivates discussion of design options for hard XFEL driver accelerators. Firstly, multiple superconducting radio-frequency (SRF) driven systems are now online (European XFEL), in construction (LCLS-II), or in design (MARIE); these provide increasing evidence of the transformational potential they offer for fundamental science with its concomitant benefits. Secondly, operation of 12 GeV CEBAF* validates use of recirculation in high energy SRF linacs. Thirdly, advances in the analysis and control of effects such as coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have been recently achieved. Collectively, these developments offer insights providing extended facility science reach, reduced costs, multiplicity (i.e., support of numerous FELs operating over a range of wavelengths), and enhanced scalability and upgradability (to higher powers and energies). We will discuss the relationship amongst the various threads, and indicate how they inform design choices for the system architecture of an option for the UK-XFEL** - that of a staged multi-user X-ray FEL and nuclear physics facility based on a multi-pass recirculating SRF CW linac.
*M. Spata, "12 GeV CEBAF Initial Operations and Challenges", these proceedings.
**P. Williams et al., Proc. FLS2018, Shanghai, China (March 2018).

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THPMK139

Design of 9/6 MeV S-band Electron Linac Structure with 1.5 Bunching Cells

coupling, bunching, electron, simulation

4635

Y. Joo, P. Buaphad, H.R. Lee
University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
S.C. Cha, Y. Kim
KAERI, Daejon, Republic of Korea

Funding: University of Science and Technology of Korea
The Korea Atomic Energy Research Institute (KAERI) has been developing several 9/6 MeV dual energy S-band RF electron linear accelerators (linacs) for non-destructive testing such as container inspection system. Until now the bunching cell of the linac has a full-cell geometry. However, to maximize the acceleration of electrons after emission from the electron gun, the geometry of the first bunching cell is modified from a full-cell to a half-cell. The optimization of Q-factor and flatness of electric field along the linac structure can be obtained by adjusting diameters of bunching and power coupling cells. By adjusting gap of the first side-coupling cell, we can optimize the field ratio between the bunching cells and normal accelerating cells. In this paper, we describe design concepts of a 9/6 MeV linac with 1.5 bunching cells as well as optimization of RF parameters such as the quality factor, resonance frequency, and electric field distribution.

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THPMK148

Design Study on Linac-bsed Laser-cmpton Scattering X-Ray Source

cavity, laser, electron, photon

4651

K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
M.K. Fukuda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
Y. Koshiba
RISE, Tokyo, Japan
M. Washio
Waseda University, Tokyo, Japan

We have been developing a laser-Compton scattering X-ray source using multi-bunch linac and optical enhancement cavity. This combination have a possibility to realize a high brightness compact X-ray source. A key issue of the system is around interaction point. Compatibility of electron focusing, optical cavity and X-ray path is difficult in the current setup. Thus we propose to use rf transverse deflecting cavity for crab crossing of laser and electron. In this conference, design study of the whole laser-Compton X-ray source consist of electron linac and optical enhancement cavity will be reported. The system configuration, resulting flux and brightness, and its applications will be discussed.

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THPML012

Simulations and Measurements of the Wakefield Loading Effect in Argonne Wakefield Accelerator Beamline

wakefield, experiment, acceleration, higher-order-mode

4675

J. Upadhyay, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
M.E. Conde, Q. Gao, N.R. Neveu, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
N.R. Neveu
IIT, Chicago, Illinois, USA

A beam driven acceleration experiment in a photonic band gap (PBG) structure is planned at Argonne wakefied accelerator (AWA) facility at Argonne National Laboratory. We plan to pass a high charge (drive) beam through a travelling wave 11.7 GHz PBG structure and generate a wakefield. This wakefield will be probed by a low charge (witness) beam to demonstrate wakefield acceleration and deceleration. The drive and witness bunches will be accelerated to above 60 MeV in the main accelerator at AWA which has frequency of 1.3 GHz. The charges used in this experiment could be as high as 20 nC. To measure the exclusive effect of PBG the structure on acceleration and deceleration of the witness bunch we have to exclude the effect of beam loading of the main AWA accelerator structure. To understand the wakefield effect in AWA, we conducted an experiment where we passed the high charge (10 nC) beam through the accelerator structure which was followed by a 2 nC witness beam separated by 4 wavelength. The energy of witness beam was measured in the presence and absence of the drive beam. The beam loading was observed and quantified. The results of this work will be presented in the conference.

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THPML017

Beam Dynamics Calculation of a New Injection System for LINAC II

gun, electron, injection, operation

4687

J.X. Zhang, M. Hüning
DESY, Hamburg, Germany

The Linac II at DESY (Deutsches Elektronen Synchrotron) is an electron/positron linear accelerator with a 400 MeV primary electron linac, an 800 MW positron converter, and a 450 MeV secondary electron/positron linac. For reliability two injection systems can be switched, a 150 kV bombarder diode gun dating from 1969 and a 100 kV triode gun commissioned in 2014. The older bombarder gun shall be replaced with a triode gun optimized for injection into the synchrotron radiation facility PETRA III. In this paper, the parameters of the existing injectors and the design considerations for the new injector are presented. The preliminary beam dynamics calculation of the new injection system will be performed; the future plan of the replacement will be discussed.

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THPML032

Using Deep Reinforcement Learning for Designing Sub-Relativistic Electron Linac

network, electron, cavity, acceleration

4720

Shin, S.W. Shin, J.-S. Chai, M. Ghergherehchi
SKKU, Suwon, Republic of Korea

Generally, when designing an accelerator device, the design is based on the experience and knowledge of the designer. Most of the design process proceeds by chang-ing the parameters and looking at the trends and then determining the optimal values. This process is time-consuming and tedious. In order to efficiently perform this tedious design process, a method using an optimization algorithm is used. Recently, many people started to get interested in the algorithm used in AlphaGo, which became famous when it won the professional Go player developed by google The algorithm used in AlphaGo is an algorithm called reinforcement learning that learns how to get optimal reward in various states by moving around a solution space that the agent has not told beforehand. In this paper, we will discuss about designing an particle accelerator by applying Deep Q-network algorithm which is one kind of deep learning reinforcement learning.

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THPML067

SXFEL Linac BPM System Development and Performance Evaluation

FEL, experiment, status, electron

4794

F.Z. Chen, T. Wu
SSRF, Shanghai, People's Republic of China
J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu, R.X. Yuan
SINAP, Shanghai, People's Republic of China

Shanghai Soft X-ray Free Electron Laser (SXFEL) is a test facility to study key technologies and new FEL physics. In order to deliver high quality electron beams to the undulator section, a high resolution (better than 10 microns with 200pC beam) Linac beam position monitor system has been developed. The system consists of stripline pickup and custom designed DBPM processor. The hardware and software architecture will be introduced in this paper. The online performance evaluation results will be presented as well.

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THPML073

Measurement of the RF Reference Phase Stability in the SuperKEKB Injector LINAC

klystron, controls, feedback, booster

4815

N. Liu
Sokendai, Ibaraki, Japan
D.A. Arakawa, H. Katagiri, T. Matsumoto, S. Michizono, T. Miura, F. Qiu, Y. Yano
KEK, Ibaraki, Japan

The SuperKEKB injector is a more than 600 m J-shaped LINAC. The requirement of the RF phase refer-ence stability is 0.1 degree (RMS) at 2856 MHz for SuperKEKB PHASE-2 commissioning. In order to clari-fy and improve the reference line performance, the RF reference phase stability is measured. The phase noise of the RF reference at each sector is shown in this paper. A new phase monitor system is implemented to measure the short-term stability and long-term drift due to the temperature and humidity fluctuations in the klystron gallery.

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THPML076

Design of Control System for Dual-Head Radiation Therapy

controls, radiation, electron, Ethernet

4826

H.S. Kim, J.-S. Chai, M. Ghergherehchi, D.H. Ha, J.C. Lee, H. Namgoong, J.H. Seo, Shin, S.W. Shin
SKKU, Suwon, Republic of Korea
D. Lipka
DESY, Hamburg, Germany

Sungkyunkwan University groups have been developed advanced radiation therapy machine named dual-head radiation therapy gantry for reducing the treatment time by up to 30%. The main difference between previous radiation therapy machine is using two electron LINAC as X-ray sources at radiation therapy. In support of this system, control system based on SCADA and hardware development was implemented. The control system consists of supervisory computers and local controllers and the control network was ethernet and software was written by labVIEW. An overview of this control system is presented in paper.

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THPML077

Status of the Machine Protection System for ARIEL e-linac

MMI, electron, TRIUMF, cryomodule

4829

M. Alcorta, D. Dale, H. Hui, S.R. Koscielniak, K. Langton, K. LeBlanc, M. Rowe
TRIUMF, Vancouver, Canada

The Advanced Rare Isotope & Electron Linac (ARIEL) facility at TRIUMF consists of an electron linear accelerator (e-linac) capable of currents up to 10 mA at an energy of 30 MeV, giving a total available beam power of 300 kW. In addition, the e-linac can be run in pulsed operation down to beam pulses of 5 μs, up to CW. A Machine Protection System (MPS) is required to protect the accelerator from hazardous beam spills and must turn off the electron gun within 10 μs of detection. The MPS consists of two types of beam loss monitors, a front-end beam loss monitor board developed at TRIUMF, and EPICS-based controls to establish operating modes. A trip time of 10 μs has been demonstrated, along with a 10⁶ dynamic range and sensitivity down to 100 pA. This paper is focused on the current status of the beam loss monitor detection system.

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THPML081

Beam-Based Measurements of the ISAC-II Superconducting Heavy Ion Linac

cavity, ISAC, alignment, TRIUMF

4841

S. Kiy, R.E. Laxdal, M. Marchetto, S.D. Rädel, O. Shelbaya
TRIUMF, Vancouver, Canada

Preparation for experiments, which typically run for one to two weeks in the ISAC-II facility at TRIUMF, requires some amount of overhead, limiting the efficiency of the facility. Efforts are underway to improve the ISAC-II linac model to reduce this overhead while also improving the quality of the delivered ion beam. This can be accomplished with beam-based measurements and corrections of alignment, cavity gradients, focal strengths, and more. A review of the present state of the linac will be given, including measured mis-alignments and other factors that affect the reproducibility of tunes. The outlook on expected improvements will also be summarized, including progress on the automatic phasing of cavities with a focus on integration to the High Level Application platform being developed at TRIUMF. Lastly, a summary will be given on the expected paradigm shift in the tuning approach taken: moving from re-active tuning by operators or beam delivery experts to pro-active measurements and investigations, version-controlled tunes, and continuous feedback from beam physicists.

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THPML087

First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System

operation, recirculation, MMI, lattice

4859

M. Arnold, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, M. Steinhorst
TU Darmstadt, Darmstadt, Germany
C. Eschelbach, M. Lösler
Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
F. Hug
KPH, Mainz, Germany

Funding: Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
The S-DALINAC is running in recirculating operation since 1991. In 2015/2016 a major upgrade was performed by adding a third recirculation beam line. The versatility of this recirculation beam line enables a phase shift of the beam of up to 360° of the RF phase. The required range of 10 cm for a 3 GHz RF frequency is realized by a path length adjustment system. A complementary operation in normal scheme (single-pass, once or thrice recirculating with acceleration) or ERL mode (once or twice) is possible by appropriate adjustment of this system. After installation this system was aligned properly and its functionality and stroke was checked without beam. The system was commissioned by measuring the change of the beam phase in dependency of the setting of the path length adjustment system. The complementary usage of the newly installed recirculation for once recirculating with acceleration and once recirculating with ERL mode has been shown successfully in autumn 2017. This contribution will provide an overview on the path length adjustment system and the first run of the once recirculating ERL mode of the S-DALINAC.

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THPML092

Electromagnetic and Mechanical Design of High Gradient S-Band Accelerator in TTX

scattering, HOM, cavity, laser

4876

D.Z. Cao, H.B. Chen, Y. C. Du, W. Gai, W.-H. Huang, J. Shi, C.-X. Tang, P. Wang, H. Zha
TUB, Beijing, People's Republic of China

Thomson scattering x-ray source is an essential scien-tific research tool in x-ray imaging technology for vari-ous fields. Upgrading plan of replacing the 3-meter S-band linac with a shorter structure operating at higher gradient in Tsinghua Thomson scattering X-ray source (TTX) is undergoing so far, aiming to enhance the accel-erating gradient from 15 MV/m to 30 MV/m. Detailed parameters of couplers and mechanical design of acceler-ation structure are presented in this work.

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THPML102

Field and Cost Optimization of a 5 T/m Normal Conducting Quadrupole for the 10-MeV Beam Line of the eLINAC of the Mexican Particle Accelerator Community

quadrupole, power-supply, multipole, operation

4905

D. Chavez Valenzuela, G.H.I. Maury Cuna, M. Napsuciale Mendivil
Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
J. C. Basilio Ortiz
CINVESTAV, Mexico City, Mexico
P.M. McIntyre, A. Sattarov
Texas A&M University, College Station, USA
C.A. Valerio
ECFM-UAS, Culiacan, Sinaloa, Mexico
B. Yee-Rendón
KEK, Ibaraki, Japan

The Mexican Particle Accelerator Community is currently designing the first Mexican RF eLINAC that will have three beamlines at 10, 60 and 100 MeV. In this work, we present an optimized design in terms of field quality and production cost for the 5 T/m normal conducting quadrupoles of the 10-MeV beamline. Several candidate materials for the yoke were studied based on their availability and machinability, with the aim to optimize in-house production cost (Mexico) while restricting a low multipole content.

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THPML119

A Time-of-Flight Based Energy Measurement System for the LIGHT Medical Accelerator

MMI, rfq, proton, cavity

4951

F. Galizzi
University of Bergamo, Bergamo, Italy
M. Caldara, F. Galizzi, A. Jeff
A.D.A.M. SA, Meyrin, Switzerland

The LIGHT proton therapy facility is the first compact Linac that will deliver proton beams up to 230 MeV for cancer treatment. The proton beam is pulsed; pulses repetition rate can reach 200 Hz. LIGHT prototype is currently being commissioned by AVO/ADAM at CERN, while the first full installation is foreseen in 2019. Beam energy translates directly to range penetration in the body, so it is of the utmost importance to monitor it accurately especially for Linacs, since each beam pulse is directly transported to the patient. We present the implementation of a non-interceptive beam energy measurement system based on the Time-of-Flight technique. Unlike state of the art ToF systems this one has been designed to measure autonomously the mean energy of the beam with medical resolution (0.03 %) by processing as little as 1 us of data providing the result within 1 to 2 ms over an energy range from 5 to 230 MeV. The first results for beams up to 7.5 MeV are shown.

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THPML122

Beta-SRF - A New Facility to Characterize SRF Materials near Fundamental Limits

SRF, cavity, TRIUMF, accelerating-gradient

4961

E. Thoeng
UBC & TRIUMF, Vancouver, British Columbia, Canada
R.A. Baartman, R.E. Laxdal, B. Matheson, G. Morris, N. Muller, S. Saminathan
TRIUMF, Vancouver, Canada
A. Chen
UBC, Vancouver, Canada
T. Junginger
Lancaster University, Lancaster, United Kingdom

Funding: Natural Sciences and Engineering Research Council of Canada (NSERC) & UBC (NSERC) IsoSiM Program
Demands of CW high-power LINAC require SRF cavities operating at the frontier of high accelerating gradient and low RF power dissipation, i.e. high quality factor (Q₀). This requirement poses a challenge for standard surface treatment recipes of SRF cavities. In a recent breakthrough, elliptical SRF cavities doped with Nitrogen have been shown to improve Q₀ by a factor of 3, close to the fundamental SRF limit. The fundamental mechanisms at microscopic level and optimum doping recipe, however, have still not fully been understood. Materials other than Nb have also been proposed for SRF cavities to overcome the fundamental limit already reached with Nitrogen doping, e.g. Nb₃Sn, MgB₂, and Nb-SIS multilayer. At TRIUMF, a unique experimental facility is currently being developed to address these issues. This facility will be able to probe local surface magnetic field in the order of the London Penetration Depth (several tens of nm) via \beta decay detection of a low-energy radioactive ion-beam. This allows depth-resolution and layer-by-layer measurement of magnetic field shielding effectiveness of different SRF materials at high-parallel field (up to 200 mT). Design and current development of this facility will be presented here, as well as commissioning and future measurements strategies for new SRF materials.

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THPML125

Efficiency Analysis of High Average Power Linacs for Environmental and Industrial Applications

impedance, beam-loading, higher-order-mode, coupling

4970

M. Shumail, V.A. Dolgashev
SLAC, Menlo Park, California, USA

Funding: U.S. Department of Energy, HEP under Research Opportunities in Accelerator Stewardship: LAB 16-1438.
We present comprehensive efficiency equations and useful scaling laws to optimally determine design parameters for high efficiency rf linacs. For the first time we have incorporated the parasitic losses due to the higher order cavity modes into the efficiency analysis of the standing wave (SW) and travelling wave (TW) accelerators. We have also derived the efficiency equations for a new kind of attenuation-independent-impedance travelling wave (ATW) accelerators where the shunt impedance can be optimized independent of the group velocity. We have obtained scaling laws which relate the rf to beam efficiency to the linac length, beam aperture radius , phase advance per cell, and the type of accelerating structure: SW versus TW, disk-loaded (DL) versus nose-cone (NC). We give an example of using these scaling laws to determine a feasible set of parameters for a 10 MeV, 10 MW linac with 97.2% efficiency.

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THPML126

Design of High Efficiency High Power CW Linacs for Environmental and Industrial Applications

cavity, simulation, solenoid, focusing

4974

M. Shumail, V.A. Dolgashev, C.M. Markusen
SLAC, Menlo Park, California, USA

Funding: US Department of Energy, Office of High Energy Physics, through Accelerator Stewardship Grant
We have used our accelerator design toolbox equations to design three high efficiency and high power CW accelerators for the environmental and medical applications. These are: 2MeV-1MW, 10MeV-10MW, and 10MeV-1MW linacs. These are all 10 m long, 1.3 GHz, π-mode standing wave structures with design efficiencies of 96.8, 97.4 and 86.5 %, and optimal coupling coefficients of 32.9, 43.5, and 7.45, respectively. We present the detailed design parameters of these linacs. The study of single-bunch beam breakup for these linacs and the simulations results from ABCI are also included. The initial cavities are optimized according to the speed of the electron bunch to maximize the shunt impedance. The plots of peak surface fields on these cavities are also presented. We have also included a detailed thermal analysis of these linacs. Finally, we present the results of ASTRA simulations of the three linacs with magnetic focusing. We have also included the complete design of rf-distributed-coupling manifold for the third linac along with the HFSS® simulation results.

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THPML132

Cryogenic Performance of an SRF Deflecting Cavity Fabricated Using Alternative Techniques for the ARIEL eLinac

cavity, SRF, niobium, cryogenics

4992

D.W. Storey
Victoria University, Victoria, B.C., Canada
R.E. Laxdal, Z.Y. Yao
TRIUMF, Vancouver, Canada

A 650 MHz SRF deflecting mode cavity has been built and tested for use as a three-way beam separator in the ARIEL eLinac. The cavity operates in a TE-like mode, and has been optimized for high shunt impedance with minimal longitudinal footprint. The device is the first SRF cavity to be fully fabricated in house at TRIUMF. The requirements of the cavity allowed for the development of low cost manufacturing techniques, including the use of Reactor grade niobium and atmospheric pressure TIG welding. The cavity has been fabricated and tested at 4 K and 2 K, obtaining a 4 K Qo of 4·10⁸ at the operating voltage of 0.3 MV, surpassing the goal voltage and quality factor required for operation. Results of the cryogenic tests of the cavity will be presented here.

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FRXGBD3

Application of Carbon Nanotube Wire for Beam Profile Measurement of Negative Hydrogen Ion Beam

electron, rfq, operation, beam-loading

5022

A. Miura, K. Moriya
JAEA/J-PARC, Tokai-mura, Japan
T. Miyao
KEK, Ibaraki, Japan

A wire scanner monitor using metallic wire is reliably employed for the beam profile measurement in the J-PARC linac. Because the loading of negative hydrogen (H⁻) ion beam on a wire increases under high-current beam operation, we focus on using a high-durability beam profile monitors by attaching another wire material. Carbon nanotubes (CNT) are made of graphite in a cylindrical shape and have a tensile strength not less than 100 times that of steel. The electric conductivity has higher than that of metals, and hardness is endured thermally around 3000°C in a vacuum circumstance. We applied the CNT wires to WSM and measured transverse profiles with a 3-MeV and 191-MeV H⁻ beam. As a result, we obtained the equivalent signal levels taken by carbon wire made of polyacrylonitrile without any damage. In this paper, the signal response when the CNT is irradiated with an H⁻ beam and the result of beam profile measurement. In addition, the surface of CNT after 3-MeV beam operation was observed.

Slides FRXGBD3 [2.558 MB]

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FRXGBF1

Re-Acceleration of Ultra Cold Muon in J-PARC Muon Facility

rfq, experiment, acceleration, emittance

5041

Y. Kondo, K. Hasegawa, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
S. Bae, H. Choi, S. Choi, B. Kim, H.S. Ko
SNU, Seoul, Republic of Korea
Y. Fukao, K. Futatsukawa, N. Kawamura, T. Mibe, Y. Miyake, M. Otani, K. Shimomura, T. Yamazaki, M. Yoshida
KEK, Tsukuba, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
T. Iijima, Y. Sue
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Iinuma, Y. Nakazawa
Ibaraki University, Ibaraki, Japan
K. Ishida
RIKEN Nishina Center, Wako, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
S. Li
The University of Tokyo, Graduate School of Science, Tokyo, Japan
G.P. Razuvaev
Budker INP & NSU, Novosibirsk, Russia
N. Saito
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Funding: This work is supported by JSPS KAKENHI Grant Numbers JP15H03666, JP16H03987, and JP16J07784.
J-PARC is developing the reacceleration system of the ultra slow (30 meV) muon (USM) obtained by two-photon laser resonant ionization of muonium atoms. The muon beam thus obtained has low emittance, meeting the requirement for the g-2/EDM experiment. J-PARC E34 experiment aims to measure the muon anomalous magnetic moment (g-2) with a precision of 0.1 ppm and search for EDM with a sensitivity to 10^-21 e cm. The USM's are accelerated to 212 MeV by using a muon dedicated linac to be a ultra cold muon beam. The muon LINAC consists of an RFQ, a inter-digital H-mode DTL, disk and washer coupled cell structures, and disk loaded structures. The ultra-cold muons will have an extremely small transverse momentum spread of 0.1% with a normalized transverse emittance of around 1.5 pi mm-mrad. Proof of the slow muon acceleration scheme is an essential step to realize the world first muon linac. In October 2017, we have succeeded to accelerate slow negative muoniums generated using a simpler muonium source to 89 keV. In this talk, present design of the muon linac and the result of the world first muon acceleration experiment are reported.

Slides FRXGBF1 [8.373 MB]

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