LINAC2018 - Table of Session: THPO (Thursday Poster Session)

Paper	Title	Page
THPO001	Design Study on CEPC Positron Damping Ring System	672
	D. Wang, Y.L. Chi, J. Gao, D.J. Gong, C. Meng, G. Pei, J.R. Zhang IHEP, Beijing, People’s Republic of China
	The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of linac and hence reduce the beam loss in the booster. Before damping ring, an energy spread compression structure is designed to match the RF acceptance of damping ring. A longitudinal bunch length control is also necessary to meet the energy spread requirement in the linac by a bunch compressor system after the damping ring. Both designs for damping ring and energy/bunch compressors are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO001
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO002	Investigation of SRF Elliptical Cavities Made by New Nb Materials in KEK	676
	T. Dohmae, K. Umemori, Y. Watanabe, M. Yamanaka KEK, Ibaraki, Japan T. Okada Sokendai, Ibaraki, Japan
	Cost reduction for cavity fabrication is currently main issue to realize international linear collider. Cavity fabrication facility (CFF) in KEK is approaching this issue from a point of view of materials for cavities. CFF had fabricated SRF elliptical cavities made by two types of niobium; one is high tantalum contained and low RRR (< 100) fine grain niobium, and the other is high tantalum contained and RRR < 300 large grain (LG) niobium. Former was melted two times (normally five times) which results RRR recovery up to around 300, and used for cell parts. Two 3-cell cavities were fabricated for each material respectively and vertical tested. One of these cavity made by LG achieved accelerator gradients of more than 40 MV/m. In this report, cavity materials and vertical test results are presented in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO002
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO003	L-band Resonant Ring for Testing RF Windows for ILC	679
SPWR005	use link to see paper's listing under its alternate paper code
	B. Du, N. Liu Sokendai - Hayama, Hayama, Japan T. Matsumoto, S. Michizono, T. Miura, F. Qiu KEK, Ibaraki, Japan T. Matsumoto, T. Miura, F. Qiu Sokendai, Ibaraki, Japan
	A resonant ring is widely used for the breakdown test of RF components under high power. It can reach power gain of more than 10dB, which is limited by the attenua-tion of the ring. An L-band resonant ring is constructed for testing RF components of International Linear Collid-er (ILC) which is based on an RF frequency of 1.3GHz. The target of the high power test is 5 MW. We have fin-ished the test of an input power of 500 W using a solid state amplifier, and the principle of the resonant ring is verified. The resonant ring is tuned to an optimal condi-tion, which is preparation for high power operation. This paper details the principle, construction, and test of the L-band resonant ring.
	Poster THPO003 [2.301 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO003
About •	paper received ※ 13 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO004	Pulsed Operation of CEBAF for JLEIC Injection	682
	J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. JLab Electron Ion Collider (JLEIC) is planning to use the recently upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The JLEIC electron injection requires 3-4µs long bunch trains with a 20-400ms spacing in between, resulting in uneven beam loading for the CW CEBAF. With the high beam current in JLEIC collider rings, the low duty factor of injection also requires to a very high pulsed beam current from CEBAF, exacerbating the transient beam loading issue. In this paper, we will present CEBAFs detailed pulsed operation scheme for JLEIC injection, as well as some experimental results at CEBAF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004
About •	paper received ※ 20 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO005	High Aspect Ratio Beam Generation with the Phase-space Rotation Technique for Linear Colliders	685
	M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan P. Piot Northern Illinois University, DeKalb, Illinois, USA J.G. Power ANL, Argonne, Illinois, USA K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan M. Washio RISE, Tokyo, Japan H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Funding: This work is partly supported by Grant-in-Aid for Scientific Research (B) and US-Japan Science and Technology Cooperation Program in High Energy Physics. Linear colliders is the only way to realize e⁺ e⁻ collision at higher energy beyond the limit of ring colliders by the huge synchrotron radiation energy loss. In the linear collider, the beam current should be much smaller comparing to the ring collider to save the required electricity. A way to realize an enough luminosity with the small beam current and less energy spread by Beamstrahlung, is collision in flat beam. This high aspect ratio beam can be made by phase-space rotation technique instead of the conventional way with DR (Damping Ring). We present a simulation of this technique and pilot experiments at KEK-STF and ANL WFA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO005
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO006	Status of 650 MHz SRF Cavity for eRHIC SRF Linac	688
	W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, F.J. Willeke, Q. Wu, A. Zaltsman BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. A 5-cell 650 MHz SRF cavity was designed for eRHIC SRF linac. One Cu cavity was fabricated for HOM damping study, and one Nb cavity was fabricated for SRF studies. Through various post-processing recipes and vertical tests, the SRF study includes high Q-value study for ERL SRF linac and high gradient study for recirculating linac. This paper reports the HOM damping measurement on the Cu cavity and preliminary vertical test results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO006
About •	paper received ※ 22 August 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO007	MESA - Status of the Implementation of the MicroTCA.4-based LLRF Control System	691
	J.N. Bai, K. Aulenbacher, J. Diefenbach, F. Fichtner IKP, Mainz, Germany P. Echevarria HZB, Berlin, Germany R.G. Heine KPH, Mainz, Germany
	MESA at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz is a multi-turn energy recovery linac (ERL), aiming to serve as user facility for particle physics experiments. The RF-accelerating systems of MESA consist of four 9-cell TESLA superconducting cavities, four normal conducting (NC) pre-accelerator cavities, two NC buncher cavities and two NC chopper cavities. They operate in continuous wave (CW) mode. In order to control the radio frequency (RF) amplitude and phase within the 12 cavities with the required accuracy and stability in the range of better than 0.01% and 0.01°, the MicroTCA.4 based digital low-level RF (LLRF) control system based on the development at DESY, Hamburg will be well adapted for the MESA cavities. In this paper, we describe the theoretical modelling of superconducting cavity and PID controller in SIMULINK which is useful to find the suitable control parameter for the PID controller and to predict the system performance. The progress to date of the implementation and tests of the LLRF system at MESA will also be presented.
	Poster THPO007 [1.274 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO007
About •	paper received ※ 11 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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THPO008	Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK	695
	H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori KEK, Ibaraki, Japan
	We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO009	Evaluation of 60pC Beam Performance at cERL Injector for ERL Based EUV-FEL	699
SPWR001	use link to see paper's listing under its alternate paper code
	T. Hotei Sokendai, Ibaraki, Japan R. Kato, T. Miyajima KEK, Ibaraki, Japan
	In order to compensate for the emittance which is increased by space charge in the low energy region, it is important to transport the beam as designed. Until now, we did not consider couplers in injector superdonducting cavities in optics design. But in this study, to improve optics matching and emittance compensation conditions for space charge dominated beam in cERL at KEK, we introduced a new 3D cavity model. We first investigated the influence of the couplers on electromagnetic field distribution. As a result, it was found that an asymmetric focusing force is generated by the influence of the couplers. It also became clear that the influence of the coupler kick on the optics significantly devastated the emittance compensation condition from the calculating including space charge. Furthermore, it was found that by optimizing the optics in consideration of the coupler kick, it is possible to improve the beam control accuracy and reduce the emittance in beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO009
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO010	Novel Straight Merger for Energy Recovery Linacs	702
	K.E. Deitrick, A. Hutton JLab, Newport News, Virginia, USA A.C. Bartnik, C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA S.A. Overstreet ODU, Norfolk, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO011	First Energy Recovery Operation at the S-DALINAC: RF Control Stability Measurements	706
	M. Steinhorst, M. Arnold, N. Pietralla TU Darmstadt, Darmstadt, Germany C. Burandt HIM, Mainz, Germany
	Funding: *Supported by the DFG through GRK 2128. One of the main research instruments at the institute for nuclear physics at the TU Darmstadt is the recirculating superconducting linear accelerator S‑DALINAC. Many improvements were implemented since the first recirculated beam in 1991. One of the major enhancement is the upgrade from a twice to a thrice recirculating scheme in 2015/2016. With this upgrade the operation mode can be changed between a conventional accelerating operation and energy recovery linac (ERL) mode by an 180° rf phaseshift of the beam done via a path length variation of the arcs in the second recirculation. ERL operation was not possible when the rf control system for the superconducting structures was set up in 2010. Therefore the current rf control system is not optimized for this kind of operation and so it had to be tested during ERL operation in order to also demonstrate its capability of this operation mode. In August 2017 a first once recirculating ERL operation was achieved. During this operation measurements regarding the rf control stability and the demand of rf power were done. This contribution is discussing this measurements and possible improvements for future energy recovery beam times.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO011
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO012	Once Recirculating Energy Recovery Linac Operation of S-DALINAC*	710
	M. Arnold, J. Birkhan, J. Pforr, N. Pietralla, F. Schließmann, M. Steinhorst TU Darmstadt, Darmstadt, Germany F. Hug KPH, Mainz, Germany
	Funding: *Work supported by DFG through GRK 2128 and INST163/383-1/FUGG Since 1991 the superconducting S-DALINAC is running in recirculating operation. It was built in a twice recirculating layout. A third recirculation beam line was added in 2015/2016 as an upgrade. The new recirculation beam line is installed in-between the two existing beam lines. It houses a path length adjustment system capable of changing the length of the orbit for recirculation by up to 10 cm corresponding to the RF wave length at the operation frequency of 3 GHz and consequently to a freedom of RF phase adjustment by 360°. The new beam line can, thus, be utilized for an accelerating operation or, if the change in phase is set to 180°, for an energy recovery linac (ERL) operation. In August 2017 the S-DALINAC was first operated in once recirculating ERL mode and became the first running ERL in Germany. Different aspects of this ERL run have been observed and were evaluated. The layout of the S-DALINAC allows a once or twice recirculating ERL mode. Beam dynamics simulations for both modes have been conducted or are currently under investigation. This contribution will discuss the once recirculating ERL operation, its results, and future plans concerning ERL measurements.
	Poster THPO012 [0.708 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO012
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO016	Investigation of 2D PBG Waveguides for THz Driven Acceleration	714
SPWR007	use link to see paper's listing under its alternate paper code
	A. Vint, R. Letizia Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Letizia Lancaster University, Lancaster, United Kingdom
	Funding: Work supported by the STFC PhD Studentship Novel accelerating techniques that overcome the limitations of conventional RF technology are receiving significant interest. Moving from RF to the THz frequency range, higher gradient of acceleration of high energy beams can be achieved in miniaturised structures. Moreover, with respect to the optical frequency range, the THz regime allows for larger structures and better beam quality to be obtained. In this paper, we investigate the use of a 2D photonic bandgap (PBG) waveguide for THz driven electron acceleration. In accelerator applications, the properties of PBG waveguides can be exploited to damp higher order modes and offer low-loss dielectric confinement at high frequency. In particular, 2D PBG waveguides offer a good compromise between manufacturability, total photonic bandgap confinement, and ease of parallel illumination. The structure here proposed is optimised for maximum bandgap and single mode operation. Dispersion characteristics of the accelerating mode are studied to achieve the best compromise between high accelerating field and effective accelerating bandwidth, given a ~10% bandwidth of the THz driving pulse.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO016
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO017	Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment	717
SPWR009	use link to see paper's listing under its alternate paper code
	M.R. Rehman Sokendai, Ibaraki, Japan K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa KEK, Ibaraki, Japan H. Iinuma Ibaraki University, Hitachi, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216. A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase. *H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO018	Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises	721
	V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase SLAC, Menlo Park, California, USA A. Grudiev CERN, Geneva, Switzerland H. Zha TUB, Beijing, People’s Republic of China
	Accelerating structures are usually manufactured by precision turning of individual cells combined with precision milling for complex parts such as rf power couplers. These multiple parts are staked and brazed into a complete structure. We consider an alternative approach: precision milling of multiple cells and couplers into metal blocks that comprise halves or quadrants of the complete structure. We successfully produced a 12~GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype using this method. A previous prototype was designed as an open structure with a gap between cell irises. Here we describe a different approach, an accelerating structure which is brazed through irises. It is based on a multi-cell traveling wave structure designed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises structure was built at SLAC for high power tests at CERN. Here we describe the details of this process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO018
About •	paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO020	Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator	725
	Y.T. Yuan HUST, Wuhan, People’s Republic of China K. Fan Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China Y. Jiang Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
	Funding: the National Natural Science Foundation of China The cyclotron auto-resonance accelerator (CARA) is a novel concept of accelerating continuous gyrating charged-particle beams to moderately or highly relativistic energies, which can be used as the high power microwave source and applied in environment improvement area, particularly in the flue gas pollution remediation. In CARA, the continuous-wave (CW) electron beam follows a gyrating trajectory while undergoing the interaction with the rotating TE-mode rf field and tapered static magnetic field. In the process of gyrating acceleration, the phase synchronization with the rf field is automatically maintained, so to speak, with auto-resonance. Simulation models are constructed to study the effect of rf field and static magnetic field on electron beam in CARA, where the beam energy, trajectory and velocity component are analysed. The simulation results match reasonably well with theoretical predication, which sets up a solid foundation for future designs of CARA.
	Poster THPO020 [1.448 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO020
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO021	Research on X Ray Characteristics Produced by Highenergy Picosecond Electron Beam Shooting	729
	X.D. Zhang, X.P. Ouyang, B. Sun, X.J. Tan, X.F. Weng NINT, Xi’an, People’s Republic of China
	Funding: Supported by National Natural Science Foundation of China(11375142) The X ray sources based on electron linac can produce X-rays with high energy, concentrated directions, and strong penetrating power, which have been widely applied in various fields. An electronic linear accelerator which has been built at present can provide an electron beam with energy of 120 MeV and pulse width of picosecond. The electron beam shooting at the metal targets can produce ultra-fast pulsed X-rays in the order of picosecond. In this paper, the pulse X ray characteristics are studied through simulating electron beam shooting at four metal targets with different thickness of Au, Ta, U, W and Pb by MCNPX program. The calculation shows that the X-rays can reach about 1010p/pulse and the pulse width can reach about picosecond level, when the pulsed electron beams with energy of 120 MeV ,charge of 0.5nC and pulse width of picosecond shooting at Ta targets. The yield and time width of pulsed X-rays are related to the diameter and thickness of the target.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO021
About •	paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO022	Development Progress of the H⁺/H⁻ Linear Accelerators at Tsinghua University	732
THOP06	use link to see paper's listing under its alternate paper code
	Q.Z. Xing, C.B. Bi, C. Cheng, C.T. Du, T.B. Du, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, S. Shuai, R. Tang, X.W. Wang, X.D. Xudong, H.Y. Zhang, S.X. Zheng TUB, Beijing, People’s Republic of China W.Q. Guan, Y. He, J. Li NUCTECH, Beijing, People’s Republic of China W.L. Liu, B.C. Wang, Z.M. Wang, Y. Yang, C. Zhao NINT, Shannxi, People’s Republic of China
	We present, in this paper, the development progress of the 13MeV proton linac for the Compact Pulsed Hadron Source (CPHS), and the 7MeV H⁻ linac injector for the synchrotron of the Xi’an 200MeV Proton Application Facility (XiPAF).
	Slides THPO022 [4.421 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO022
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO026	The Multi-physics Analysis of Dual-beam Drift Tube Linac	735
	T. He, L. Lu, W. Ma, L.P. Sun, C.C. Xing, X.B. Xu, L. Yang IMP/CAS, Lanzhou, People’s Republic of China
	The DB-DTL prototype is proposed to validate the fea-sibility of multi-beam accelerator in middle energy region. The main parameters are listed in Table.1. The DB-DTL will operate as pulse injector with the capacity of accelerating proton from 0.56 MeV to 2.5 MeV. The 35.83 kW normalized power dissipation of DB-DTL dis-sipated on the cavity internal surface will heat the cavity and cause cavity temperature rise and structural defor-mation, which will lead to resonant frequency shifting. The cooling water takes away the power to resolve this problem. In this paper, detailed multi-physics field simu-lation of DB-DTL is performed by using ANSYS multi-physics, which is a coupled electromagnetic, thermal and structural analysis.
	Poster THPO026 [0.759 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO026
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO028	Magnetic Field Measurement and Analysis for Drift Tube Linac of CSNS	738
	B. Li, M.X. Fan, A.H. Li, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, W. Kang, H.C. Liupresenter, J.X. Zhou IHEP, Beijing, People’s Republic of China
	Funding: The National Natural Science Foundation of China(11105166)； Youth Innovation Promotion Association（2015011） A 324MHz Alvarez-type Drift Tube Linac (DTL) is used to accelerate the H⁻ ion beam from 3 to 80 MeV with peak current 15mA for China Spallation Neutron Source (CSNS). DTL is composed by 36 meters cavity and 161 DTs, the DT magnet coil adopted SAKAE structure with compact, smaller aperture. Magnetic field is measured by self-developed high precision rotating coil measurement system. This paper introduces the rotating coil measure-ment system simply and presents the 161 DTs magnetic field measurement results comprehensively, include mag-netic field center offset, integral magnetic field, higher-order harmonics. In addition, cooling test result of magnet coil is also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO028
About •	paper received ※ 31 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO029	Quality Factor and Power Loss of the CSNS DTL	741
	P.H. Qu, M.X. Fan, A.H. Li, B. Li, J. Peng, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liupresenter IHEP, Beijing, People’s Republic of China
	An Alvarez-type Drift tube linac (DTL) was utilized to accelerate the H⁻ ion beam of up to 15mA peak current from 3 to 80MeV of China Spallation neutron source (CSNS). For ease of manufacturing and measurement, the CSNS DTL was divided into four independent cavities. The Q factor of four cavities were given, including the measurement results of low-power[1] and high-power[2], and several reasons for the low Q factor of the cavity in the measurement process were analysed. During the op-eration of the DTL, the frequent alarm of the water flow switch causes the power of the cavity to fall to 0. Esti-mate the power loss of each component, under the cir-cumstances of ensuring adequate water flow, reduce the alarm threshold of the water flow switch of some compo-nents to improve the stability of the system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO029
About •	paper received ※ 22 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO030	Operation Experience of the CSNS DTL	744
	H.C. Liu, Q. Chen, S. Fu, K.Y. Gong IHEP, Beijing, People’s Republic of China M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) Drift tube linac (DTL) accelerates H⁻ beam from 3 to 80MeV with 4 independent tanks. The 80MeV beam acceleration was achieved in January 2018. The linac is a key to the reliability of the whole CSNS facility since all the beams stop when these upstream facilities fail. Many efforts have been made for DTL reliable operation. This paper presents the operation experience learned in DTL com-missioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO030
About •	paper received ※ 28 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO031	RF Conditioning and Beam Commissioning Status of CSNS DTL	747
	Y. Wang, M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liupresenter IHEP, Beijing, People’s Republic of China
	The high power RF conditioning of CSNS DTL was finished in April 2017 with peak input power 1.6MW, 650us pulse width, 25Hz repetition frequency. With careful tuning of RF amplitude and phase, beam was accelerated to 80MeV successfully with maximum peak beam current 12mA and about 98% transmission efficiency. DTL operate stably at full power level with several trips per day without beam interruption after six months commissioning. The whole RF conditioning process was presented and some details of beam commissioning were described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO031
About •	paper received ※ 05 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO032	CSNS Linac Beam Commissioning Tools and Experience	750
	Y. Li, Z.P. Li, S. Wang IHEP, Beijing, People’s Republic of China J. Pengpresenter CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) successfully accelerated the H⁻ beam to 80 MeV in January 2018, marking a key progress in the beam commissioning. One of the keys to success is the development and use of software tools. XAL, a Java-based software infrastructure originally developed by SNS was applied for CSNS beam commissioning. We have developed and transplanted many applications based on XAL. Some of the applications for the Linac are described ,and some experiences are shared.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO032
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO033	The Development of Permanent Magnet Quadrupoles for Xipaf DTL	753
	B.C. Wang, M.T. Qiu, Z.M. Wang, C.Y. Wei NINT, Shannxi, People’s Republic of China C.T. Du, Q.K. Guo, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China
	Permanent magnet quadrupoles (PMQs) are developed for the DTL of Xi’an 200 MeV Proton Application Facility (XiPAF). In this paper, we describe the fabrication and measurements for the Halbach-type PMQs. The main procedure of the PMQ manufacture is presented. And the magnetic measurements of PMQs are carried out with the help of vibrating wire, Hall probe and rotating coil respectively. The results show the PMQs are able to meet the requirements of XiPAF DTL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO033
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO034	Experimental Study of Tuning Method on a Model Alvarez DTL Cavity for CPHS Project	756
	Y. Lei, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China
	This article is devoted to the experimental study of tun-ing method for an Alvarez-type drift tube linac (DTL) of the Compact Pulse Hadron Source (CPHS) project at Tsinghua University. The biperiodic structure based on the post couplers are introduced to overcome the instability of the Alvarez DTL tank which is used to operate in 0 (or 2π) mode. The experimental method and results are pre-sented, and the tuning scheme for the formal CPHS DTL is summarized from the tuning experiment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO034
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO035	Tuning and Low Power Test of the 325 MHz IH-DTL at Tsinghua University	759
	R. Tang, C.T. Du, X. Guan, Y. Lei, P.F. Ma, K.D. Man, C.-X. Tang, X.W. Wang, Q.Z. Xing, W.B. Ye, H.Y. Zhang, S.X. Zheng TUB, Beijing, People’s Republic of China J. Li NUCTECH, Beijing, People’s Republic of China
	An interdigital H-mode drift tube linac (IH-DTL), which accelerates proton beam from 3 MeV to 7 MeV has been designed and assembled at Tsinghua University. There are 8 plungers in the 1 m tank and one co-axial coupler is used to feed the power. The frequency is tuned to 325 MHz. The field distribution is measured by the bead perturbation method. Finally, the gap voltage error has been tuned to be smaller than ±3.0%, which satisfies the design requirement. The Q factor of the tank is 7000 while the power dissipation is 244 kW. Details of the low power test is presented.
	Poster THPO035 [1.268 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO035
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO036	Error Study of CPHS DTL after Assembly	763
SPWR014	use link to see paper's listing under its alternate paper code
	P.F. Ma, C.T. Du, X. Guan, Q.K. Guo, Y. Lei, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China B.C. Wang NINT, Shannxi, People’s Republic of China
	The Compact Pulsed Hadron Source (CPHS) at Tsinghua University is one multi-purpose pulsed neutron source. The injector of the CPHS is a linac, which mainly consists of a source, a low-energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The error study of the DTL for CPHS is presented in this paper. The error study can provide the field tolerances in the DTL cavity and the alignment tolerance between the RFQ and DTL.
	Poster THPO036 [2.645 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO036
About •	paper received ※ 06 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO038	Status of the Power Couplers for the CSNS DTL	767
	M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liu IHEP, Beijing, People’s Republic of China
	There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10^-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented. This work was supported by Youth Innovation Promotion Association of CAS (2015011)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038
About •	paper received ※ 30 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO039	The Status of CSNS Front End	771
	H. Li, X. Cao, W. Chen, T. Huang, S. Liu, K. Xue CSNS, Guangdong Province, People’s Republic of China S. Fu, Y.J. Lv, H.F. Ouyang, Y.C. Xiaopresenter IHEP, Beijing, People’s Republic of China
	CSNS front end is currently under running, which consists of a H⁻ penning ion source(IS), a low energy beam transport(LEBT), a radio frequency quadrupole (RFQ) and a medium energy beam transport(MEBT). CSNS ion source is a type of Penning surface plasma source, similar to ISIS ion source. Cesium is used to enhance the H⁻ ion production efficiency. The ion source is running with duty factor of 1.25%(25Hz and 500us). Normally, 40mA H⁻ beam from ion source with 50keV can be delivered into LEBT. Three solenoids and two direction magnets are employed to transport and match the beam from the ion source into the RFQ. The pre-chopper is installed at the end of LEBT. The chopper mainly works at 3.8-4.2 kV and 1 MHz rate, which is about the RF frequency of the ring at injection. The rise time is less than 10ns，which fulfills the requirement of ring injection. For the RFQ, it is a 324MHz 4-vane type with a output energy of 3.0MeV and the length of 3.62m. The input cavity power is about 400kW. During commissioning, 16mA H⁻ beam can be obtained at the exit of RFQ, and the RFQ transmission rate is up to 94%.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO039
About •	paper received ※ 03 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO040	Operation Experiences of the J-PARC Linac	774
	K. Hasegawa JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC linac has delivered beam to users since 2008. As of 2018, the linac provides a 40 mA beam at an energy of 400 MeV to the following Rapid Cycling Synchrotron. We have had many issues to impede high availability during the operation. One of them was troubles of high voltage power supply of klystrons. The other category is related to vacuum property in accelerating cavities. The vacuum pumps were reinforced at the RFQ#1 in 2009. The cleaning of the inside surface of some acceleration cavities were performed after the big earthquake in 2011. The cooling water flow rate drop had been a long-time issue. We modified a cooling system to take better flow balances. As a result of these improvement, the availability is approximately 92% or more in these days. However, we have encountered another issue due to some aging components. The operation experiences and availability improvement at the J-PARC linac will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040
About •	paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO042	An Optimization Method of the Nose-cone Buncher Cavity	778
	W.L. Liu, P.T. Cong, Z.M. Wang NINT, Shannxi, People’s Republic of China H. Jiang, S.X. Zheng TUB, Beijing, People’s Republic of China
	The nose-cone buncher cavity is widely used on proton accelerators. It’s important to properly optimize the cavity geometry for fine RF performance. Howev-er, currently the optimization is usually carried out manually and the criteria are not objective enough. In this paper, an optimization method using the multi-objective, multi-variable optimization approach is presented. The geometry and RF parameters are con-sidered as the variables and objectives respectively. The goal function is defined as the weighted sum of multiple RF parameters. The multi-variable functions are approximately derived from the single-variable functions based on electromagnetic simulation. And an optimization code is developed accordingly which has been applied to the XiPAF debuncher optimization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO042
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO043	ESS Normal Conducting Linac Status and Plans	781
	E. Sargsyan, H. Danared, F. Hellström, G. Hulla, Ø. Midttun, J.S. Schmidt ESS, Lund, Sweden I. Bustinduy, N. Garmendia, J.L. Muñoz ESS Bilbao, Zamudio, Spain L. Celona, S. Gammino, L. Neri INFN/LNS, Catania, Italy A.C. Chauveau, B. Pottin CEA/IRFU, Gif-sur-Yvette, France F. Grespanpresenter, A. Pisent INFN/LNL, Legnaro (PD), Italy P. Mereu INFN-Torino, Torino, Italy
	The European Spallation Source (ESS) uses a linear accelerator to deliver the high intensity proton beam to the target station for producing intense beams of neutrons. The average beam power is 5 MW with a peak beam power at the target of 125 MW. The normal conducting linear accelerator (linac) operating at 352.21 MHz accelerates a proton beam of 62.5 mA from 0.075 to 90 MeV. It consists of an ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), Medium Energy Beam Transport (MEBT), and Drift Tube Linac (DTL). The design, construction and testing of those structures is done by European partner labs as an in-kind contribution to the ESS project. This paper presents the status and plans for the ESS normal conducting linac. E.Sargsyan for the ESS NC Linac collaboration team
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO043
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO045	Tuning Esperience on the ESS DTL Cold Model	784
	F. Grespan, A. Baldo, P. Bottin, G.S. Mauro, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy P. Mereu, M. Mezzano INFN-Torino, Torino, Italy
	An aluminum model of the ESS DTL tank 2 has been delivered to INFN-LNL in december 2017. The tank is 7.1 m long, equipped with movable tuners and movable post couplers. The purpose of this DTL model is to verify the RF design choices (in particular on the first 2 tanks where the Post coupler distribution is irregular) as well as implement and debug algorithms and procedure for stabilization and tuning. The preparatory simulation work and the results of measurements campaign are here presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO045
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO046	Status of the FAIR Proton Linac	787
	C.M. Kleffner, S. Appel, R. Berezov, J. Fils, P. Forck, M. Kaiser, K. Knie, C. Mühle, S. Puetz, A. Schnase, G. Schreiber, A. Seibel, T. Sieber, V. Srinivasan, J. Trüller, W. Vinzenz, C. Will GSI, Darmstadt, Germany A. Almomani, H. Hähnel, U. Ratzinger, M. Schuett, M. Syha IAP, Frankfurt am Main, Germany
	As part of the accelerator chain for antiproton production of the FAIR facility, a special high-intensity short pulsed 325 MHz proton linac is being developed. The Proton linac is designed to deliver a beam current of 70 mA with an energy of 68 MeV. A 2.45 GHz ECR source designed for the generation of 100 mA beams with an energy of 95 keV is currently being tested at CEA/Saclay. The production of the structure of the IAP ladder RFQ is nearly completed. First parts of the RFQ vacuum chambers have been successfully copperplated at the GSI. Seven Thales Klystrons have been delivered to GSI at the beginning of 2018 and are nearly ready for use. The completion of the setup of the HV modulator is expected end of the year 2018. The state of procurement and development of further accelerator components will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO046
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO047	SPIRAL2 Injector Commissioning	790
THOP01	use link to see paper's listing under its alternate paper code
	R. Ferdinand, M. Di Giacomo, H. Franberg, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle, F. Varenne GANIL, Caen, France D. Uriot CEA/DRF/IRFU, Gif-sur-Yvette, France
	The SPIRAL2 injector is composed of two ion sources (p/d and heavy ions up to A/Q=3) followed by a 730 keV/u RFQ. Beam commissioning has started in 2014 in parallel with the superconducting linac and HEBT installations. The RFQ beam commissioning started soon after the first RF conditioning done in October 2015. This paper describes the RFQ beam measurements done on the diagnostic plate for the reference particles (H⁺, 4He2+ and recently 18O6+) and the difficulties encountered for the RFQ commissioning at the A/Q=3 field level.
	Slides THPO047 [7.846 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO047
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO048	Low Power Measurement of a 1300-MHz RFQ Cold Model	794
THOP02	use link to see paper's listing under its alternate paper code
	Y. Kondo, T. Morishita, J. Tamura JAEA/J-PARC, Tokai-mura, Japan M. Otani KEK, Ibaraki, Japan
	Funding: This work is supported by JSPS KAKENHI Grant Number 17K18784. A muon linac development for a new muon g-2/EDM experiment is now going on at J-PARC. Muons from the muon beam line (H-line) of the J-PARC muon facility are once stopped in a silica aerojel target and room temperature muoniums are evaporated from the aerogel. They are dissociated with the lasers to be the ultra slow muons, then accelerated up to 212 MeV using a linear accelerator. The low energy part of this muon linac consists of a 324-MHz RFQ and an IH DTL. The frequency is increased to 1296 MHz at the following CCL section. We propose to replace the low energy section to a 1300-MHz RFQ to simplify the configuration of the muon linac. The 1300-MHz RFQ will be extremely small compared to conventional RFQs, therefore we made a cold model to proof the feasibility of this scheme. In this paper, the result of low-power measurement of the 1300-MHz RFQ cold model is described.
	Slides THPO048 [2.160 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO048
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO049	Field Tuning of a Radio-frequency Quadrupole Using Full 3D Modeling	798
	T. Morishita, K. Hasegawa, Y. Kondo, H. Oguri JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan M. Otani KEK, Ibaraki, Japan
	The radio-frequency quadrupole linac (RFQ) is operating in the frontend of the J-PARC linac to accelerates 50 mA negative hydrogen beams from 0.05 MeV to 3 MeV. As a backup, the spare RFQ has been fabricated in 2018. The vane-voltage ramping is adopted to improve the acceleration efficiency so that the cross-sectional shape is adjusted longitudinally to produce the designed voltage distribution. Then, the three-dimensional cavity models including modulations and cutbacks were created in CST Micro-Wave Studio. The vane-base widths and cutback depths were optimized to produce the desired vane-voltage distribution. In the final tuning, the heights of the stub turners were also determined based on the tuner responses obtained from the full 3D models. In this paper, the detailed design process of the cavity dimensions and the result of the low-power measurements are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO049
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO050	Research on the New Cavity Structure of RFQ Accelerator With Bent Vanes at IMP	802
THOP03	use link to see paper's listing under its alternate paper code
	L. Yang, T. He, Y. He, C.X. Li, L. Lu, L.P. Sun, C.C. Xing IMP/CAS, Lanzhou, People’s Republic of China L. Yang University of Chinese Academy of Sciences, Beijing, People’s Republic of China
	A new cavity structure of RFQ accelerator with bent vanes is proposed to meet the miniaturization requirement of low frequency heavy ion accelerators at Institute of Modern Physics (IMP), Chinese Academy of Sciences. The new structure has a downsized cross section by bending vanes while keeping a certain vane lengths. It also possesses the advantages of simple cooling structure and high power efficient when used in low frequency. The new structure has obvious advantages in reducing manufacturing difficulty of cavity, cutting down project cost, enhancing facility reliability and stability.
	Slides THPO050 [1.407 MB]
	Poster THPO050 [0.398 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO050
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO051	The Multi-physics Analysis of LEAF RFQ	805
	X.B. Xu, T. He, Y. He, C.X. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, C.C. Xing, L. Yang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	The 81.25 MHz CW RFQ is designed to accelerate heavy ions with Q/A from 1/7 to 1/2 at 0.5 MeV/u for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). The four-vane RFQ consists of six mod-ules with a total length of 5.95 meters, For the CW oper-ating mode, thermal management will be a very important issue, Therefore a multi-physics analysis is necessary to ensure that the cavity can stably operate at the high RF power . The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and the frequency shift, the cooling water system is used for frequency tunning by the temperature adjustment, and also analyze RFQ undercuts, fixed tuners, and pi-mode rods, the results show that the thermal and structural design of this RFQ is reasonable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO051
About •	paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO052	High Power Test of the LEAF-RFQ	808
	L. Lu, Y. He, W. Ma, L.B. Shi, L.T. Sun, L.P. Sun, L. Yang, Y. Yang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	High power heavy ion drivers require a CW low-frequency accelerator for initial acceleration. A CW four-vane radio frequency quadrupole (RFQ) accelerator is designed to accelerate heavy ions A/q up to 7 from 14 keV/u to 500 keV/u, as a new injector for the Low Energy Accelerator Facility (LEAF) at Institute of Modern Physics (IMP). The measurements of low power test were reported previously. In this paper, the results of high power test of the RFQ, including the test of the acceleration systems and beam profiles, will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO052
About •	paper received ※ 07 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO053	Status of the China Material Irradiation Facility RFQ	811
	C.X. Li, W.L. Chen, W.P. Dou, Z. Gao, Y. He, G. Huang, C.L. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, F.F. Wang, W.B. Wang, Z.J. Wang, Q. Wu, X.B. Xu, L. Yang, P.Y. Yu, B. Zhang, J.H. Zhang, P. Zhang, T.M. Zhu IMP/CAS, Lanzhou, People’s Republic of China
	Funding: Supported by the National Magnetic Confinement Fusion Science Program of China (Grant No.2014GB104001) and the National Natural Science Foundation of China (Grant No.91426303). The pulsed high power test and beam test of the China Material Irradiation Facility RFQ have been implemented. Before this, the radio frequency measurements and tuning are performed. In this paper, the processes and results of the radio frequency measurements, tuning, pulsed high power test and beam test will be presented. The results of tests are in good agreement with the design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO053
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO054	Recent Progress of a CW 4-rod RFQ for the SSC-LINAC	814
	Z.S. Li, Y. Cong, H. Du, Y. He, L. Jing, Q.Y. Kong, X.N. Li, J. Meng, G.D. Shen, K.D. Wang, Z.J. Wang, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, W.J. Xie, Z. Xu, J.C. Yang, Y.Q. Yang, X. Yin, Y.J. Yuan, Y. Zhang IMP/CAS, Lanzhou, People’s Republic of China Y.R. Lu PKU, Beijing, People’s Republic of China
	The SSC-LINAC is under design and construction as a linear injector for the Separated-Sector Cyclotron (SSC) of the Heavy Ion Research Facility at Lanzhou (HIRFL). The continuous-wave (CW) 4-rod radio-frequency quad-rupole (RFQ) of the SSC-LINAC has important progress in past years. In the autumn of 2016, the cavity has been operated with 35 kW on CW mode in automatic RF con-trolled mode during RF power commissioning, which is needed to accelerate 238U³⁴⁺ beams. The beam transmis-sion efficiency, transverse emittance and energy spread has been obtained in beam commissioning. In this paper, the results of experiments will be presented and discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO054
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO057	Redesign of CERN Linac3 RFQ for Lead 29+	818
	S. Benedetti, G. Bellodi, J.-B. Lallement, A.M. Lombardi CERN, Geneva, Switzerland
	CERN Linac3 is at the start of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates 208Pb²⁹⁺, though in recent years runs were performed with 40Ar¹¹⁺ and 129Xe²²⁺, in view of the increasing interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for 208Pb²⁵⁺, the lower beam rigidity of the heavy ions currently in use and planned for the future permits a redesign of the RFQ optics aimed at increasing its transverse acceptance, and thus the transmitted beam current. A study of this has been performed, and the methodology adopted and the results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO057
About •	paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO058	RF Design of a High-frequency RFQ Linac for PIXE Analysis	822
SPWR016	use link to see paper's listing under its alternate paper code
THOP04	use link to see paper's listing under its alternate paper code
	H.W. Pommerenke, A. Bilton, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins, M. Vretenar CERN, Geneva, Switzerland H.W. Pommerenke, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: This work has been sponsored by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E12CHA). Protons with an energy of few MeV are commonly used for Ion Beam Analysis of materials, in particular with the Proton Induced X-ray Emission technique (PIXE). Because of its non-damaging character, PIXE is used in a variety of fields, in particular for the diagnosis of cultural heritage artwork. A compact accelerator based on a high frequency RFQ (Radio Frequency Quadrupole) linac has been designed and is being built at CERN. The length of the RFQ is only one meter and it allows the acceleration of a proton beam up to an energy of 2 MeV. The complete system is conceived to be transportable, allowing PIXE analysis almost anywhere. This paper covers the RF design of the compact RFQ operating at 750 MHz. We present general accelerator parameters and the current state of the RF design, which includes RFQ geometry and coupler design, thermal simulation and first particle tracking results.
	Slides THPO058 [2.404 MB]
	Poster THPO058 [2.192 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO058
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO060	First RF Measurements of the 325 MHz Ladder RFQ	826
	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 prototype Ladder-RFQ features a very constant voltage along the axis. The RFQ was high power tested at the GSI test stand. It accepted 3 times the RF power level 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 higher symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. For the present design duty cycles are feasible up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in August 2018. We will show the the finalization of manufacturing as well as first low level RF measurements of the Ladder RFQ. Journal of Physics: Conf. Series 874 (2017) 012048 **Proceedings of LINAC2016, East Lansing, TUPLR053
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO060
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO061	Beam Characterization of the MYRRHA-RFQ	830
SPWR017	use link to see paper's listing under its alternate paper code
	P.P. Schneider, M. Droba, O. Meusel, H. Podlech, A. Schempp IAP, Frankfurt am Main, Germany D. Noll CERN, Geneva, Switzerland
	Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and HORIZON 2020 for the MYRRHA project #662186 and HIC for FAIR. The Linear Accelerator for the MYRRHA project* is under construction. In a first step the linac up to 100 MeV will be realized. The LEBT section has been set into operation in Belgium and the RFQ is installed in summer 2018. A system to analyze the ion beam consisting of a slit-grid emittance scanner, a beam dump and a momentum spectrometer, called diagnostic train descripted in *, will be set on the rails to characterize the beam at the RFQ injection point. The results will be used to adjust the optimal matching for the RFQ. After the measurements downstream the LEBT, the diagnostic train begins its journey along the beam line and at the first station the RFQ is installed. The accelerated beam of the RFQ is then analyzed and optimized. In addition to optimization of transmission the artificial production of beam offsets in the LEBT is of special interest. These will be measured at the injection point to estimate the range of possible offsets. In the following measurements these offsets will be used to study the influence of the offsets on the RFQ performance. Furthermore, the RFQ parameters are varied to see their influence on the beam transport, transmission and beam quality. H.Aı̈t Abderrahim et al. "MYRRHA: A multipurpose accelerator driven system for research & development", 2001 ** 1st Experiments at the CW-Operated RFQ for Intense Proton Beams, LINAC16
	Poster THPO061 [4.610 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO061
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO062	IFMIF/EVEDA RFQ Preliminary Beam Characterization	834
	E. Fagotti, L. Antoniazzi, L. Bellan, M. Comunian, F. Grespanpresenter, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo INFN/LNL, Legnaro (PD), Italy T. Akagi, K. Kondo, K. Sakamoto, T. Shinya, M. Sugimoto QST, Aomori, Japan P. Cara IFMIF/EVEDA, Rokkasho, Japan H. Dzitko, I.M. Moya F4E, Germany R. Heidinger, A. Marqueta Fusion for Energy, Garching, Germany I. Podadera CIEMAT, Madrid, Spain
	The IFMIF/EVEDA RFQ is the longest and powerful operated. Therefore, it requires a careful characterization from several aspects: beam dynamics, RF, mechanics, installation and commissioning. Due to the very large power handling, the preliminary beam operation was decided to be performed with a low proton beam current at one half of the voltage needed for deuteron accelera-tion, i.e. from 8 mA to 30 mA at 2.5 MeV in pulsed mode, with respect to the nominal 130-mA deuteron beam at 5 MeV in CW. In this framework, it will be presented the characterization of the RFQ in terms of simulation and measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO062
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO064	Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility	838
	X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China B.C. Wang, Z.M. Wang, C. Zhao NINT, Shannxi, People’s Republic of China
	This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi’an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H⁻ beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 μs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode com-ponent is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning.
	Poster THPO064 [1.413 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO066	First High Power Test of the ESS High Beta Elliptical Cavity	841
THOP05	use link to see paper's listing under its alternate paper code
	H. Li, L. Hermansson, M. Jobs, R.J.M.Y. Ruber, R. Santiago Kern Uppsala University, Uppsala, Sweden G. Devanz, T. Hamelin CEA/DSM/IRFU, France
	ESS, the European Spallation Source, will adopt elliptical multi-cell superconducting cavities with a beta value of 0.86 to accelerate the proton beam up to 2 GeV at the last section of the linac. A 5-cell high-beta cavity for ESS project was tested with high power at FREIA Laboratory. A pulse mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involved a 5-cell elliptical cavity, a fundamental power coupler, a cold tuning system, LLRF system and a RF station. These tests represented an important verification before the series production. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.
	Slides THPO066 [1.437 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO066
About •	paper received ※ 14 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO067	Control System and Experiment for RAON HWR Cryomodules	845
	H. Kim, J.W. Choi, C.O. Choi, H. Jang, Y.W. Jo, H.C. Jung, Y. Jung, J.W. Kim, M.S. Kim, Y. Kim, D.Y. Lee, M. Lee, S. Lee, K.T. Seol, K.T. Son IBS, Daejeon, Republic of Korea
	A prototype of half-wave resonator (HWR) cryomodules is fabricated and tested. Cables and tray are installed for horizontal test. The design and the piping and instrumentation diagram (P&ID) of the HWR cryomodule are presented. The HWR cryomodule is tested with developed programmable logic controller (PLC) and experimental physics and industrial control system (EPICS) control systems. The heat loads of the HWR cryomodule for static and dynamic are measured.
	Poster THPO067 [0.631 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO067
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO068	AN Effect of Field Emission on Low Beta Superconducting Cavities	849
SPWR011	use link to see paper's listing under its alternate paper code
	X. Liu, Z. Gao, Y. He, G. Huang IMP/CAS, Lanzhou, People’s Republic of China
	Superconducting RF (SRF) technology is widely ap-plied in particle accelerators to shorten the accelerator length and lower the construction price due to its high acceleration gradients with low rf losses. Field emission is the chief limitation associated with the surface electric field which will finally determine the cavity performance during the operation. The pickup-drop signal caused by field emission seriously affect the stable operation of the superconducting linac in the Chinese initiative Accelera-tor-Driven Sub-critical System (CiADS) demon facility. Simulations of the field emission effect and experimental measurements of the pickup-drop signal have been per-formed on the half wavelength resonator (HWR) cavity. And a modified design of the pickup antenna will be discussed to solve the pickup-drop problem.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO068
About •	paper received ※ 12 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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THPO069	The Electromagnetic Optimization of TE-sample Host Cavity at IMP	852
	S.C. Huang, Y. He, T. Tan, S.X. Zhang IMP/CAS, Lanzhou, People’s Republic of China
	As a part of the research and development work of thin-film materials for superconducting radio frequency(SRF) application in future accelerators at IMP, a 3.9GHz TE sample host cavity is being developed for the purpose of characterizing the RF Property and the loss mechanism of thin-film materials, which operates in the TE011 mode and accommodates disk sample with 110mm diameter, theoretically, the maximum magnetic field on sample surface will go up to 100mT, the resolution of surface resistance on sample will below nOhm by using thermometry technique( T-Mapping). In this paper, the electromagnetic optimization result of TE-sample host cavity will be presented, and the design consideration of hook tip style coupler and T-mapping system are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO069
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO072	Cryogenic Tests of the Superconducting β=0.069 CH-cavities for the HELIAC-project	855
SPWR010	use link to see paper's listing under its alternate paper code
	M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany W.A. Barth, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany
	In the future the existing UNILAC (UNIversal Linear Accelerator) at GSI will be most exclusively used as an injector for FAIR to provide short pulse high intensity heavy ion beams at low repetition rates [Barth3]. A new superconducting (sc) continuous wave (cw) high intensity heavy ion Linac should provide ion beams with max. duty factor above the coulomb barrier for the Super Heavy Element (SHE) program at GSI. The fundamental Linac design comprises a low energy beam transport (LEBT)-section followed by a sc Drift Tube Linac (DTL) consisting of sc Crossbar-H-mode (CH) structures for acceleration up to 7.3 MeV/u []. After the successful test and commissioning of the first demonstrator section with heavy ion beam from the HLI in 2017 [], the next two sc CH-structures have been constructed and the first one has been extensively tested at cryogenic temperatures at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of the final cold test of the first CH-structure as well as the next steps realizing a new sc cw heavy ion LINAC at GSI will be presented. []W. Barth et al., "Further investigations for a superconducting cw-Linac at GSI" [**]W. Barth et al., "First high intensity heavy ion beam tests with a superconducting multi gap CH-cavity"
	Poster THPO072 [1.150 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO072
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO073	RF Commissioning of the Superconducting 217 MHz CH Cavity for Heavy Ions and First Beam Operation	859
	F.D. Dziuba, K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, M. Heilmann, J. Salvatore, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	Future research programs at GSI in the field super heavy element (SHE) synthesis require high intense heavy ion beams above the coulomb barrier and high average particle currents. The upcoming demands exceed the technical opportunities of the existing UNIversal Linear ACcelerator (UNILAC). Consequently, a new dedicated superconducting (sc) continuous wave (cw) linac is crucial to keep the SHE research program at GSI competitive on a high level. Recently the first linac section, serving as a prototype to demonstrate the reliable operability of 217 MHz multi gap crossbar-H-mode (CH) cavities under a realistic accelerator environment, has been extensively tested with a heavy ion beam delivered from the GSI High Charge State Injector (HLI). Fulfilling its role as a key component of the whole demonstrator setup. The first sc 217 MHz CH cavity (CH⁰) successfully accelerated heavy ions up to the design beam energy and even beyond at high beam intensities and full transmission. In this contribution the rf commissioning and the first beam operation of the cavity is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO073
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO076	Multiphysics Design Studies of a Superconducting Quarter-wave Resonator at Peking University	863
	M. Chen, S. Chen, A.Q. Cheng, W. Cheng, J.K. Hao, S.W. Quan, F. Zhu PKU, Beijing, People’s Republic of China
	Funding: This work is supported by National Basic Research Program (2014CB845504) A 81.25MHz, geometric β=0.046 quarter-wave resonator has been designed and analysed at Peking University. This paper mainly presents the multi-physics studies of this cavity, include electromagnetic design, mechanical analysis and multipacting simulation, to predict its behaviour under practical operating process. Various transverse vibration modes of inner conductor were found under different fixed conditions and an asymmetric shorting plate was adopted to avoid high possibility of multipacting "quarter-wave resonator" "multiphysics" "multipacting" "frequency detuning" "stiffening design"
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO076
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO079	RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations	866
THOP10	use link to see paper's listing under its alternate paper code
	V.V. Paramonov RAS/INR, Moscow, Russia K. Flöttmann DESY, Hamburg, Germany
	For diagnostic of longitudinal distribution of electrons in unique REGAE bunches is applied a specially developed deflecting structure with minimized level of aberrations in the field distribution and improved RF efficiency. Short deflecting cavity was constructed and installed now in REGAE beam line. The cavity is tested at operational level of RF power. The main distinctive features of the cavity are mentioned and obtained results are reported.
	Slides THPO079 [1.803 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO080	Design Validation of a Chopping and Deflecting System for the High Current Injector at IUAC	869
	S. Kedia, R. Ahuja, R. Kumar, R. Mehta IUAC, New Delhi, India
	A chopping and deflecting system has been designed and developed to provide the chopped beam with various repetition rates at the IUAC experimental facilities. It consists of four pairs of deflecting plates with increasing gap from 15 mm to 21 mm to maximize the effective electric field, preserve the beam emittance and to maximize the transmission efficiency within the same voltage conditions. The design of CDS has been validated with various simulation codes like CST MWS, Solid Works, Python and TRACE 3D. The deflecting plates have been fabricated, and assembled with in the design accuracy of 100 microns. A vacuum chamber has been designed and fabricated to incorporate the deflector plate assembly. The CDS unit has been installed in the Low Energy Ion Beam Facility at the IUAC to validate the design value of ion beam deflection. A slit has been installed to cut the deflected charge particles. Since the pulse power electronics required for chopping is presently under design we have used DC voltage across the four pairs of deflecting plates and amount of deflection was measured accordingly. The design, development, and DC beam test will be discussed in the article.
	Poster THPO080 [2.037 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO080
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO082	Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement	872
SPWR028	use link to see paper's listing under its alternate paper code
	J. Bai, Q.S. Chenpresenter, K. Fan HUST, Wuhan, People’s Republic of China
	Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.
	Poster THPO082 [0.484 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO083	Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro	875
	G. Kourkafas, T. Kamps, A. Neumann HZB, Berlin, Germany B. Keune RI Research Instruments GmbH, Bergisch Gladbach, Germany
	The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these ambitious goals necessitates a thorough determination of the bunch parameters after the first acceleration stages, namely the photoinjector and the succeeding booster module. For the measurement of primarily the bunch duration and subsequently the longitudinal phase space and transverse slice emittance, a single-cell 1.3-GHz TM110-like mode vertically deflecting cavity was manufactured by RI Research Instruments GmbH, following the respective design developed for the Cornell ERL injector. This article summarizes the design parameters, manufacturing procedure and testing of this pulsed RF resonator, together with the expected temporal measurement resolution for the nominal beam energies at the initial acceleration stages of BERLinPro.
	Poster THPO083 [1.396 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO083
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO084	BPM Time of Flight Measurements for Setting-up the RF Cavities of the CERN Linac4	879
	M. Bozzolan CERN, Geneva, Switzerland
	The newly constructed H⁻ LINAC4 at CERN has recently completed its first extended reliability run. It is equipped with Beam Position Monitors (BPMs) based on shorted-stripline pick-up electrodes to measure both position and Time of Flight (ToF). The ToF, in turn used to calculate the kinetic energy of the beam, is determined through signal phase shift measurements between pairs of BPMs. ToF measurements are performed by scanning of the phase of the RF injected into the cavities to find the nominal RF settings for optimal beam acceleration. This paper focuses on the technical aspects of the ToF measurement as well as on the results obtained during beam commissioning and their comparison with beam dynamics simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO084
About •	paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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THPO086	Beam Loss and Average Beam Current Measurements Using a CWCT	882
	F. Stulle, H. Bayle, J.F. Bergoz, T. Delaviere, L. Dupuy BERGOZ Instrumentation, Saint Genis Pouilly, France P. Forck, M. Witthaus GSI, Darmstadt, Germany D. Vandeplassche SCK•CEN, Mol, Belgium J.X. Wu IMP/CAS, Lanzhou, People’s Republic of China
	The CWCT is a novel instrument adapted to an accurate average current determination of bunched CW beams or macro pulses. By combining a high-droop current transformer with novel electronics for signal analysis, an output signal bandwidth of DC to about 500kHz and a current resolution down to the micro-ampere level are achieved. Beam current fluctuations are followed within microseconds, permitting fast detection of beam loss. These characteristics render the CWCT an ideal instrument for HPPAs, for example ADS linacs, and other proton or ion accelerators. We present the CWCT principle and the CWCT performance achieved in beam experiments at UNILAC, GSI.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO086
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO090	The Analysis of Module Failure in High Solid-state Amplifier for High Current RFQ	886
	L.P. Sun, Y. He, G. Huang, C.X. Li, L. Lu, A. Shi, L.B. Shi, X.B. Xu, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	New accelerator RF system was upgraded to the solid-state amplifier in ADS project due to its stable, sustainable and reliable. Until now, newest 80kW SSA was adopted in IMP, operating in 162.5MHz, and over 120 power modules were combined through several synthesizers for 80kW output. but since too many modules were optimized for amplitude and phase in the same time, one or some failure of circulator will lead to injure of whole RF system, when wavelength meets a specific condition, injure would turn out severe accident and heavy loss. In this paper, analyzing and simulating the multi-level synthetic matrix was the important method for ADS accident happened in June 20. 2017, the failure simulated results for RF amplify links under the specific circumstances also was presented simultaneously.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO090
About •	paper received ※ 17 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019
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THPO091	90 kW Solid-state RF Amplifier with a TE011-mode Cavity Power-combiner at 476 MHz	889
THOP07	use link to see paper's listing under its alternate paper code
	Y. Otake, T. Asaka, T. Inagaki RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan S. Aizawa, K. Nagatsuka, T. Okuyama, K. Sato, H. Yamada Nihon Koshuha Co. Ltd, Yokohama, Japan
	Solid-state RF amplifiers, which have long lifetimes and small failures, are the recent trend of reliable and stable high-power rf sources for particle accelerators. Hence, we designed a 90kW solid-state amplifier with an extreme low-loss TE011 mode cavity (Q0=100, 000) power-combiner operated at 476 MHz and a 6 us pulse width. Developing this amplifier is for replacement of an IOT rf amplifier, at the X-ray free-electron laser, SACLA. In SACLA, highly RF phase and amplitude stabilities of less than 0.02 deg. and 10^-4 in rms are necessary to stable lasing within a 10 % intensity fluctuation. The amplifier comprises a drive amplifier, a reentrant cavity rf power divider, 100 final amplifiers with a 1 kW output each and a TE011 mode cavity combiner. Water-cooling within 10 mK and a DC power supply with a noise of less than -100 dBV at 10 Hz for the amplifier is necessary to realize the previously mentioned stabilities. Based on the test results of the amplifier, the above-mentioned specifications with the extreme low-loss are promising. The amplifier also allows us to operate in pulsed and CW rfs for linacs and ring accelerators. We report the performance of the 90kW amplifier.
	Slides THPO091 [1.750 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO091
About •	paper received ※ 06 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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THPO092	LCLSII Fundamental Power Coupler Manufacturing Status and Lesson Learned	893
	S. Sierra, G. Garcin, Ch.L. Lievin, G. Vignette, I. Yao Leclerc TED, Velizy-Villacoublay, France M. Knaak, M. Pekeler RI Research Instruments GmbH, Bergisch Gladbach, Germany
	Thales and RI Research Instrument have manufactured and assembled half of the power couplers for the LCLSII project. This paper remains main characteristics of these coupler. It will also describe main challenges that were overcome among them, thickness of copper coating on Warm Internal Conductor at 150µm and lessons learned during the manufacturing phase of these couplers. The paper will also propose some possible optimization for a future mass production of such components and parameters which could be relevant for a better understanding link to the statistic results obtained.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO092
About •	paper received ※ 10 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO093	Status and Results Obtained on a RF Conditioning Test Bench for 704 MHz Couplers in the Frame of ESS Project	895
	S. Sierra, Y. Amal, Ch.L. Lievin, I. Yao Leclerc TED, Velizy-Villacoublay, France M.E. Chahbazian, J.G. De_Oliveira, A.G. Goeury, L.J. Nennig, S.P. Petitjean GERAC Thales, Le Barp, France
	Thales and Gerac are developing a test bench able to make the RF conditioning of the Fundamental Power Couplers at 704 MHz in the frame of the ESS project for CEA. The status of the developments of the test bench is described including the modulator, klystron and all relative equipments. The paper will also describes the results obtained at the date of presentation.

Paper

Title

Page

Design Study on CEPC Positron Damping Ring System

672

D. Wang, Y.L. Chi, J. Gao, D.J. Gong, C. Meng, G. Pei, J.R. Zhang
IHEP, Beijing, People’s Republic of China

The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of linac and hence reduce the beam loss in the booster. Before damping ring, an energy spread compression structure is designed to match the RF acceptance of damping ring. A longitudinal bunch length control is also necessary to meet the energy spread requirement in the linac by a bunch compressor system after the damping ring. Both designs for damping ring and energy/bunch compressors are discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO001

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO002

Investigation of SRF Elliptical Cavities Made by New Nb Materials in KEK

676

T. Dohmae, K. Umemori, Y. Watanabe, M. Yamanaka
KEK, Ibaraki, Japan
T. Okada
Sokendai, Ibaraki, Japan

Cost reduction for cavity fabrication is currently main issue to realize international linear collider. Cavity fabrication facility (CFF) in KEK is approaching this issue from a point of view of materials for cavities. CFF had fabricated SRF elliptical cavities made by two types of niobium; one is high tantalum contained and low RRR (< 100) fine grain niobium, and the other is high tantalum contained and RRR < 300 large grain (LG) niobium. Former was melted two times (normally five times) which results RRR recovery up to around 300, and used for cell parts. Two 3-cell cavities were fabricated for each material respectively and vertical tested. One of these cavity made by LG achieved accelerator gradients of more than 40 MV/m. In this report, cavity materials and vertical test results are presented in detail.

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO003

L-band Resonant Ring for Testing RF Windows for ILC

679

SPWR005

use link to see paper's listing under its alternate paper code

B. Du, N. Liu
Sokendai - Hayama, Hayama, Japan
T. Matsumoto, S. Michizono, T. Miura, F. Qiu
KEK, Ibaraki, Japan
T. Matsumoto, T. Miura, F. Qiu
Sokendai, Ibaraki, Japan

A resonant ring is widely used for the breakdown test of RF components under high power. It can reach power gain of more than 10dB, which is limited by the attenua-tion of the ring. An L-band resonant ring is constructed for testing RF components of International Linear Collid-er (ILC) which is based on an RF frequency of 1.3GHz. The target of the high power test is 5 MW. We have fin-ished the test of an input power of 500 W using a solid state amplifier, and the principle of the resonant ring is verified. The resonant ring is tuned to an optimal condi-tion, which is preparation for high power operation. This paper details the principle, construction, and test of the L-band resonant ring.

Poster THPO003 [2.301 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO003

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paper received ※ 13 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO004

Pulsed Operation of CEBAF for JLEIC Injection

682

J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
JLab Electron Ion Collider (JLEIC) is planning to use the recently upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The JLEIC electron injection requires 3-4µs long bunch trains with a 20-400ms spacing in between, resulting in uneven beam loading for the CW CEBAF. With the high beam current in JLEIC collider rings, the low duty factor of injection also requires to a very high pulsed beam current from CEBAF, exacerbating the transient beam loading issue. In this paper, we will present CEBAFs detailed pulsed operation scheme for JLEIC injection, as well as some experimental results at CEBAF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004

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paper received ※ 20 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO005

High Aspect Ratio Beam Generation with the Phase-space Rotation Technique for Linear Colliders

685

M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J.G. Power
ANL, Argonne, Illinois, USA
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
M. Washio
RISE, Tokyo, Japan
H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Funding: This work is partly supported by Grant-in-Aid for Scientific Research (B) and US-Japan Science and Technology Cooperation Program in High Energy Physics.
Linear colliders is the only way to realize e⁺ e⁻ collision at higher energy beyond the limit of ring colliders by the huge synchrotron radiation energy loss. In the linear collider, the beam current should be much smaller comparing to the ring collider to save the required electricity. A way to realize an enough luminosity with the small beam current and less energy spread by Beamstrahlung, is collision in flat beam. This high aspect ratio beam can be made by phase-space rotation technique instead of the conventional way with DR (Damping Ring). We present a simulation of this technique and pilot experiments at KEK-STF and ANL WFA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO005

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO006

Status of 650 MHz SRF Cavity for eRHIC SRF Linac

688

W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, F.J. Willeke, Q. Wu, A. Zaltsman
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 5-cell 650 MHz SRF cavity was designed for eRHIC SRF linac. One Cu cavity was fabricated for HOM damping study, and one Nb cavity was fabricated for SRF studies. Through various post-processing recipes and vertical tests, the SRF study includes high Q-value study for ERL SRF linac and high gradient study for recirculating linac. This paper reports the HOM damping measurement on the Cu cavity and preliminary vertical test results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO006

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paper received ※ 22 August 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO007

MESA - Status of the Implementation of the MicroTCA.4-based LLRF Control System

691

J.N. Bai, K. Aulenbacher, J. Diefenbach, F. Fichtner
IKP, Mainz, Germany
P. Echevarria
HZB, Berlin, Germany
R.G. Heine
KPH, Mainz, Germany

MESA at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz is a multi-turn energy recovery linac (ERL), aiming to serve as user facility for particle physics experiments. The RF-accelerating systems of MESA consist of four 9-cell TESLA superconducting cavities, four normal conducting (NC) pre-accelerator cavities, two NC buncher cavities and two NC chopper cavities. They operate in continuous wave (CW) mode. In order to control the radio frequency (RF) amplitude and phase within the 12 cavities with the required accuracy and stability in the range of better than 0.01% and 0.01°, the MicroTCA.4 based digital low-level RF (LLRF) control system based on the development at DESY, Hamburg will be well adapted for the MESA cavities. In this paper, we describe the theoretical modelling of superconducting cavity and PID controller in SIMULINK which is useful to find the suitable control parameter for the PID controller and to predict the system performance. The progress to date of the implementation and tests of the LLRF system at MESA will also be presented.

Poster THPO007 [1.274 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO007

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paper received ※ 11 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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THPO008

Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK

695

H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori
KEK, Ibaraki, Japan

We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO009

Evaluation of 60pC Beam Performance at cERL Injector for ERL Based EUV-FEL

699

SPWR001

use link to see paper's listing under its alternate paper code

T. Hotei
Sokendai, Ibaraki, Japan
R. Kato, T. Miyajima
KEK, Ibaraki, Japan

In order to compensate for the emittance which is increased by space charge in the low energy region, it is important to transport the beam as designed. Until now, we did not consider couplers in injector superdonducting cavities in optics design. But in this study, to improve optics matching and emittance compensation conditions for space charge dominated beam in cERL at KEK, we introduced a new 3D cavity model. We first investigated the influence of the couplers on electromagnetic field distribution. As a result, it was found that an asymmetric focusing force is generated by the influence of the couplers. It also became clear that the influence of the coupler kick on the optics significantly devastated the emittance compensation condition from the calculating including space charge. Furthermore, it was found that by optimizing the optics in consideration of the coupler kick, it is possible to improve the beam control accuracy and reduce the emittance in beam commissioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO009

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO010

Novel Straight Merger for Energy Recovery Linacs

702

K.E. Deitrick, A. Hutton
JLab, Newport News, Virginia, USA
A.C. Bartnik, C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
S.A. Overstreet
ODU, Norfolk, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the most critical design considerations for an energy recovery linac (ERL) is how to merge the injected bunch onto the linac axis with minimal beam degradation. All merger designs in established and upcoming machines involve significant bending of the injected beam ’ even using a so-called straight merger bends the injected beam several degrees. We propose a merger which reduces the bending of the injected beam by an order of magnitude. By passing both beams through a septum magnet followed by an rf separator cavity with a superimposed dipole magnetic field, the injected beam bends minimally within the cavity, while the recirculated beam bends to align with the linac axis. Here we describe the concept in detail and present simulation results to demonstrate the advantages of such a design, particularly for magnetized beams or minimal energy separation between the injected and recirculated beams. Measurements from an experiment at CBETA evaluating the beam dynamics of the rf separator are presented and compared with simulation results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010

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THPO011

First Energy Recovery Operation at the S-DALINAC: RF Control Stability Measurements

706

M. Steinhorst, M. Arnold, N. Pietralla
TU Darmstadt, Darmstadt, Germany
C. Burandt
HIM, Mainz, Germany

Funding: *Supported by the DFG through GRK 2128.
One of the main research instruments at the institute for nuclear physics at the TU Darmstadt is the recirculating superconducting linear accelerator S‑DALINAC. Many improvements were implemented since the first recirculated beam in 1991. One of the major enhancement is the upgrade from a twice to a thrice recirculating scheme in 2015/2016. With this upgrade the operation mode can be changed between a conventional accelerating operation and energy recovery linac (ERL) mode by an 180° rf phaseshift of the beam done via a path length variation of the arcs in the second recirculation. ERL operation was not possible when the rf control system for the superconducting structures was set up in 2010. Therefore the current rf control system is not optimized for this kind of operation and so it had to be tested during ERL operation in order to also demonstrate its capability of this operation mode. In August 2017 a first once recirculating ERL operation was achieved. During this operation measurements regarding the rf control stability and the demand of rf power were done. This contribution is discussing this measurements and possible improvements for future energy recovery beam times.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO011

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THPO012

Once Recirculating Energy Recovery Linac Operation of S-DALINAC*

710

M. Arnold, J. Birkhan, J. Pforr, N. Pietralla, F. Schließmann, M. Steinhorst
TU Darmstadt, Darmstadt, Germany
F. Hug
KPH, Mainz, Germany

Funding: *Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
Since 1991 the superconducting S-DALINAC is running in recirculating operation. It was built in a twice recirculating layout. A third recirculation beam line was added in 2015/2016 as an upgrade. The new recirculation beam line is installed in-between the two existing beam lines. It houses a path length adjustment system capable of changing the length of the orbit for recirculation by up to 10 cm corresponding to the RF wave length at the operation frequency of 3 GHz and consequently to a freedom of RF phase adjustment by 360°. The new beam line can, thus, be utilized for an accelerating operation or, if the change in phase is set to 180°, for an energy recovery linac (ERL) operation. In August 2017 the S-DALINAC was first operated in once recirculating ERL mode and became the first running ERL in Germany. Different aspects of this ERL run have been observed and were evaluated. The layout of the S-DALINAC allows a once or twice recirculating ERL mode. Beam dynamics simulations for both modes have been conducted or are currently under investigation. This contribution will discuss the once recirculating ERL operation, its results, and future plans concerning ERL measurements.

Poster THPO012 [0.708 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO012

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THPO016

Investigation of 2D PBG Waveguides for THz Driven Acceleration

714

SPWR007

use link to see paper's listing under its alternate paper code

A. Vint, R. Letizia
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Letizia
Lancaster University, Lancaster, United Kingdom

Funding: Work supported by the STFC PhD Studentship
Novel accelerating techniques that overcome the limitations of conventional RF technology are receiving significant interest. Moving from RF to the THz frequency range, higher gradient of acceleration of high energy beams can be achieved in miniaturised structures. Moreover, with respect to the optical frequency range, the THz regime allows for larger structures and better beam quality to be obtained. In this paper, we investigate the use of a 2D photonic bandgap (PBG) waveguide for THz driven electron acceleration. In accelerator applications, the properties of PBG waveguides can be exploited to damp higher order modes and offer low-loss dielectric confinement at high frequency. In particular, 2D PBG waveguides offer a good compromise between manufacturability, total photonic bandgap confinement, and ease of parallel illumination. The structure here proposed is optimised for maximum bandgap and single mode operation. Dispersion characteristics of the accelerating mode are studied to achieve the best compromise between high accelerating field and effective accelerating bandwidth, given a ~10% bandwidth of the THz driving pulse.

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THPO017

Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment

717

SPWR009

use link to see paper's listing under its alternate paper code

M.R. Rehman
Sokendai, Ibaraki, Japan
K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa
KEK, Ibaraki, Japan
H. Iinuma
Ibaraki University, Hitachi, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216.
A new muon g-2/EDM experiment at J-PARC (E34) is under preparation in order to resolve a 3𝜎 discrepancy of muon anomalous magnetic dipole moment between the measurement and the standard model prediction. The E34 experiment will employ a unique three-dimensional spiral injection scheme in order to store the muon beam into a small storage orbit. In order to demonstrate the feasibility of this novel injection scheme, the Spiral Injection Test Experiment (SITE) with the electron beam is under construction at KEK Tsukuba campus. The goals of the SITE are divided into two phases. In the first phase of the SITE, 80 keV DC electron beam was injected and detected as a fluorescent light due to the de- excitation of the nitrogen gas into solenoidal storage magnet. In the second phase of the SITE, the pulsed electron beam, and a pulsed magnetic kicker are developed in order to keep the pulsed beam on the very midplane of the solenoidal storage magnet. This paper describes the achievements of the first phase of SITE and progress towards the second phase.
*H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016).

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THPO018

Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises

721

V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase
SLAC, Menlo Park, California, USA
A. Grudiev
CERN, Geneva, Switzerland
H. Zha
TUB, Beijing, People’s Republic of China

Accelerating structures are usually manufactured by precision turning of individual cells combined with precision milling for complex parts such as rf power couplers. These multiple parts are staked and brazed into a complete structure. We consider an alternative approach: precision milling of multiple cells and couplers into metal blocks that comprise halves or quadrants of the complete structure. We successfully produced a 12~GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype using this method. A previous prototype was designed as an open structure with a gap between cell irises. Here we describe a different approach, an accelerating structure which is brazed through irises. It is based on a multi-cell traveling wave structure designed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises structure was built at SLAC for high power tests at CERN. Here we describe the details of this process.

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paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO020

Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator

725

Y.T. Yuan
HUST, Wuhan, People’s Republic of China
K. Fan
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
Y. Jiang
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA

Funding: the National Natural Science Foundation of China
The cyclotron auto-resonance accelerator (CARA) is a novel concept of accelerating continuous gyrating charged-particle beams to moderately or highly relativistic energies, which can be used as the high power microwave source and applied in environment improvement area, particularly in the flue gas pollution remediation. In CARA, the continuous-wave (CW) electron beam follows a gyrating trajectory while undergoing the interaction with the rotating TE-mode rf field and tapered static magnetic field. In the process of gyrating acceleration, the phase synchronization with the rf field is automatically maintained, so to speak, with auto-resonance. Simulation models are constructed to study the effect of rf field and static magnetic field on electron beam in CARA, where the beam energy, trajectory and velocity component are analysed. The simulation results match reasonably well with theoretical predication, which sets up a solid foundation for future designs of CARA.

Poster THPO020 [1.448 MB]

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THPO021

Research on X Ray Characteristics Produced by Highenergy Picosecond Electron Beam Shooting

729

X.D. Zhang, X.P. Ouyang, B. Sun, X.J. Tan, X.F. Weng
NINT, Xi’an, People’s Republic of China

Funding: Supported by National Natural Science Foundation of China(11375142)
The X ray sources based on electron linac can produce X-rays with high energy, concentrated directions, and strong penetrating power, which have been widely applied in various fields. An electronic linear accelerator which has been built at present can provide an electron beam with energy of 120 MeV and pulse width of picosecond. The electron beam shooting at the metal targets can produce ultra-fast pulsed X-rays in the order of picosecond. In this paper, the pulse X ray characteristics are studied through simulating electron beam shooting at four metal targets with different thickness of Au, Ta, U, W and Pb by MCNPX program. The calculation shows that the X-rays can reach about 1010p/pulse and the pulse width can reach about picosecond level, when the pulsed electron beams with energy of 120 MeV ,charge of 0.5nC and pulse width of picosecond shooting at Ta targets. The yield and time width of pulsed X-rays are related to the diameter and thickness of the target.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO021

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paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO022

Development Progress of the H⁺/H⁻ Linear Accelerators at Tsinghua University

732

THOP06

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Q.Z. Xing, C.B. Bi, C. Cheng, C.T. Du, T.B. Du, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, S. Shuai, R. Tang, X.W. Wang, X.D. Xudong, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People’s Republic of China
W.Q. Guan, Y. He, J. Li
NUCTECH, Beijing, People’s Republic of China
W.L. Liu, B.C. Wang, Z.M. Wang, Y. Yang, C. Zhao
NINT, Shannxi, People’s Republic of China

We present, in this paper, the development progress of the 13MeV proton linac for the Compact Pulsed Hadron Source (CPHS), and the 7MeV H⁻ linac injector for the synchrotron of the Xi’an 200MeV Proton Application Facility (XiPAF).

Slides THPO022 [4.421 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO022

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO026

The Multi-physics Analysis of Dual-beam Drift Tube Linac

735

T. He, L. Lu, W. Ma, L.P. Sun, C.C. Xing, X.B. Xu, L. Yang
IMP/CAS, Lanzhou, People’s Republic of China

The DB-DTL prototype is proposed to validate the fea-sibility of multi-beam accelerator in middle energy region. The main parameters are listed in Table.1. The DB-DTL will operate as pulse injector with the capacity of accelerating proton from 0.56 MeV to 2.5 MeV. The 35.83 kW normalized power dissipation of DB-DTL dis-sipated on the cavity internal surface will heat the cavity and cause cavity temperature rise and structural defor-mation, which will lead to resonant frequency shifting. The cooling water takes away the power to resolve this problem. In this paper, detailed multi-physics field simu-lation of DB-DTL is performed by using ANSYS multi-physics, which is a coupled electromagnetic, thermal and structural analysis.

Poster THPO026 [0.759 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO026

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO028

Magnetic Field Measurement and Analysis for Drift Tube Linac of CSNS

738

B. Li, M.X. Fan, A.H. Li, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China
Q. Chen, K.Y. Gong, W. Kang, H.C. Liupresenter, J.X. Zhou
IHEP, Beijing, People’s Republic of China

Funding: The National Natural Science Foundation of China(11105166)； Youth Innovation Promotion Association（2015011）
A 324MHz Alvarez-type Drift Tube Linac (DTL) is used to accelerate the H⁻ ion beam from 3 to 80 MeV with peak current 15mA for China Spallation Neutron Source (CSNS). DTL is composed by 36 meters cavity and 161 DTs, the DT magnet coil adopted SAKAE structure with compact, smaller aperture. Magnetic field is measured by self-developed high precision rotating coil measurement system. This paper introduces the rotating coil measure-ment system simply and presents the 161 DTs magnetic field measurement results comprehensively, include mag-netic field center offset, integral magnetic field, higher-order harmonics. In addition, cooling test result of magnet coil is also presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO028

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paper received ※ 31 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO029

Quality Factor and Power Loss of the CSNS DTL

741

P.H. Qu, M.X. Fan, A.H. Li, B. Li, J. Peng, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China
Q. Chen, K.Y. Gong, H.C. Liupresenter
IHEP, Beijing, People’s Republic of China

An Alvarez-type Drift tube linac (DTL) was utilized to accelerate the H⁻ ion beam of up to 15mA peak current from 3 to 80MeV of China Spallation neutron source (CSNS). For ease of manufacturing and measurement, the CSNS DTL was divided into four independent cavities. The Q factor of four cavities were given, including the measurement results of low-power[1] and high-power[2], and several reasons for the low Q factor of the cavity in the measurement process were analysed. During the op-eration of the DTL, the frequent alarm of the water flow switch causes the power of the cavity to fall to 0. Esti-mate the power loss of each component, under the cir-cumstances of ensuring adequate water flow, reduce the alarm threshold of the water flow switch of some compo-nents to improve the stability of the system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO029

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paper received ※ 22 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO030

Operation Experience of the CSNS DTL

744

H.C. Liu, Q. Chen, S. Fu, K.Y. Gong
IHEP, Beijing, People’s Republic of China
M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) Drift tube linac (DTL) accelerates H⁻ beam from 3 to 80MeV with 4 independent tanks. The 80MeV beam acceleration was achieved in January 2018. The linac is a key to the reliability of the whole CSNS facility since all the beams stop when these upstream facilities fail. Many efforts have been made for DTL reliable operation. This paper presents the operation experience learned in DTL com-missioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO030

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paper received ※ 28 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO031

RF Conditioning and Beam Commissioning Status of CSNS DTL

747

Y. Wang, M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China
Q. Chen, K.Y. Gong, H.C. Liupresenter
IHEP, Beijing, People’s Republic of China

The high power RF conditioning of CSNS DTL was finished in April 2017 with peak input power 1.6MW, 650us pulse width, 25Hz repetition frequency. With careful tuning of RF amplitude and phase, beam was accelerated to 80MeV successfully with maximum peak beam current 12mA and about 98% transmission efficiency. DTL operate stably at full power level with several trips per day without beam interruption after six months commissioning. The whole RF conditioning process was presented and some details of beam commissioning were described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO031

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paper received ※ 05 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO032

CSNS Linac Beam Commissioning Tools and Experience

750

Y. Li, Z.P. Li, S. Wang
IHEP, Beijing, People’s Republic of China
J. Pengpresenter
CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) successfully accelerated the H⁻ beam to 80 MeV in January 2018, marking a key progress in the beam commissioning. One of the keys to success is the development and use of software tools. XAL, a Java-based software infrastructure originally developed by SNS was applied for CSNS beam commissioning. We have developed and transplanted many applications based on XAL. Some of the applications for the Linac are described ,and some experiences are shared.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO032

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO033

The Development of Permanent Magnet Quadrupoles for Xipaf DTL

753

B.C. Wang, M.T. Qiu, Z.M. Wang, C.Y. Wei
NINT, Shannxi, People’s Republic of China
C.T. Du, Q.K. Guo, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China

Permanent magnet quadrupoles (PMQs) are developed for the DTL of Xi’an 200 MeV Proton Application Facility (XiPAF). In this paper, we describe the fabrication and measurements for the Halbach-type PMQs. The main procedure of the PMQ manufacture is presented. And the magnetic measurements of PMQs are carried out with the help of vibrating wire, Hall probe and rotating coil respectively. The results show the PMQs are able to meet the requirements of XiPAF DTL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO033

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO034

Experimental Study of Tuning Method on a Model Alvarez DTL Cavity for CPHS Project

756

Y. Lei, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China

This article is devoted to the experimental study of tun-ing method for an Alvarez-type drift tube linac (DTL) of the Compact Pulse Hadron Source (CPHS) project at Tsinghua University. The biperiodic structure based on the post couplers are introduced to overcome the instability of the Alvarez DTL tank which is used to operate in 0 (or 2π) mode. The experimental method and results are pre-sented, and the tuning scheme for the formal CPHS DTL is summarized from the tuning experiment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO034

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO035

Tuning and Low Power Test of the 325 MHz IH-DTL at Tsinghua University

759

R. Tang, C.T. Du, X. Guan, Y. Lei, P.F. Ma, K.D. Man, C.-X. Tang, X.W. Wang, Q.Z. Xing, W.B. Ye, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People’s Republic of China
J. Li
NUCTECH, Beijing, People’s Republic of China

An interdigital H-mode drift tube linac (IH-DTL), which accelerates proton beam from 3 MeV to 7 MeV has been designed and assembled at Tsinghua University. There are 8 plungers in the 1 m tank and one co-axial coupler is used to feed the power. The frequency is tuned to 325 MHz. The field distribution is measured by the bead perturbation method. Finally, the gap voltage error has been tuned to be smaller than ±3.0%, which satisfies the design requirement. The Q factor of the tank is 7000 while the power dissipation is 244 kW. Details of the low power test is presented.

Poster THPO035 [1.268 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO035

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO036

Error Study of CPHS DTL after Assembly

763

SPWR014

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P.F. Ma, C.T. Du, X. Guan, Q.K. Guo, Y. Lei, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China
B.C. Wang
NINT, Shannxi, People’s Republic of China

The Compact Pulsed Hadron Source (CPHS) at Tsinghua University is one multi-purpose pulsed neutron source. The injector of the CPHS is a linac, which mainly consists of a source, a low-energy beam transport line (LEBT), a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The error study of the DTL for CPHS is presented in this paper. The error study can provide the field tolerances in the DTL cavity and the alignment tolerance between the RFQ and DTL.

Poster THPO036 [2.645 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO036

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paper received ※ 06 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO038

Status of the Power Couplers for the CSNS DTL

767

M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China
Q. Chen, K.Y. Gong, H.C. Liu
IHEP, Beijing, People’s Republic of China

There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10^-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented.
This work was supported by Youth Innovation Promotion Association of CAS (2015011)

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038

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paper received ※ 30 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO039

The Status of CSNS Front End

771

H. Li, X. Cao, W. Chen, T. Huang, S. Liu, K. Xue
CSNS, Guangdong Province, People’s Republic of China
S. Fu, Y.J. Lv, H.F. Ouyang, Y.C. Xiaopresenter
IHEP, Beijing, People’s Republic of China

CSNS front end is currently under running, which consists of a H⁻ penning ion source(IS), a low energy beam transport(LEBT), a radio frequency quadrupole (RFQ) and a medium energy beam transport(MEBT). CSNS ion source is a type of Penning surface plasma source, similar to ISIS ion source. Cesium is used to enhance the H⁻ ion production efficiency. The ion source is running with duty factor of 1.25%(25Hz and 500us). Normally, 40mA H⁻ beam from ion source with 50keV can be delivered into LEBT. Three solenoids and two direction magnets are employed to transport and match the beam from the ion source into the RFQ. The pre-chopper is installed at the end of LEBT. The chopper mainly works at 3.8-4.2 kV and 1 MHz rate, which is about the RF frequency of the ring at injection. The rise time is less than 10ns，which fulfills the requirement of ring injection. For the RFQ, it is a 324MHz 4-vane type with a output energy of 3.0MeV and the length of 3.62m. The input cavity power is about 400kW. During commissioning, 16mA H⁻ beam can be obtained at the exit of RFQ, and the RFQ transmission rate is up to 94%.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO039

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paper received ※ 03 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO040

Operation Experiences of the J-PARC Linac

774

K. Hasegawa
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC linac has delivered beam to users since 2008. As of 2018, the linac provides a 40 mA beam at an energy of 400 MeV to the following Rapid Cycling Synchrotron. We have had many issues to impede high availability during the operation. One of them was troubles of high voltage power supply of klystrons. The other category is related to vacuum property in accelerating cavities. The vacuum pumps were reinforced at the RFQ#1 in 2009. The cleaning of the inside surface of some acceleration cavities were performed after the big earthquake in 2011. The cooling water flow rate drop had been a long-time issue. We modified a cooling system to take better flow balances. As a result of these improvement, the availability is approximately 92% or more in these days. However, we have encountered another issue due to some aging components. The operation experiences and availability improvement at the J-PARC linac will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040

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paper received ※ 19 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO042

An Optimization Method of the Nose-cone Buncher Cavity

778

W.L. Liu, P.T. Cong, Z.M. Wang
NINT, Shannxi, People’s Republic of China
H. Jiang, S.X. Zheng
TUB, Beijing, People’s Republic of China

The nose-cone buncher cavity is widely used on proton accelerators. It’s important to properly optimize the cavity geometry for fine RF performance. Howev-er, currently the optimization is usually carried out manually and the criteria are not objective enough. In this paper, an optimization method using the multi-objective, multi-variable optimization approach is presented. The geometry and RF parameters are con-sidered as the variables and objectives respectively. The goal function is defined as the weighted sum of multiple RF parameters. The multi-variable functions are approximately derived from the single-variable functions based on electromagnetic simulation. And an optimization code is developed accordingly which has been applied to the XiPAF debuncher optimization.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO042

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO043

ESS Normal Conducting Linac Status and Plans

781

E. Sargsyan, H. Danared, F. Hellström, G. Hulla, Ø. Midttun, J.S. Schmidt
ESS, Lund, Sweden
I. Bustinduy, N. Garmendia, J.L. Muñoz
ESS Bilbao, Zamudio, Spain
L. Celona, S. Gammino, L. Neri
INFN/LNS, Catania, Italy
A.C. Chauveau, B. Pottin
CEA/IRFU, Gif-sur-Yvette, France
F. Grespanpresenter, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P. Mereu
INFN-Torino, Torino, Italy

The European Spallation Source (ESS) uses a linear accelerator to deliver the high intensity proton beam to the target station for producing intense beams of neutrons. The average beam power is 5 MW with a peak beam power at the target of 125 MW. The normal conducting linear accelerator (linac) operating at 352.21 MHz accelerates a proton beam of 62.5 mA from 0.075 to 90 MeV. It consists of an ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), Medium Energy Beam Transport (MEBT), and Drift Tube Linac (DTL). The design, construction and testing of those structures is done by European partner labs as an in-kind contribution to the ESS project. This paper presents the status and plans for the ESS normal conducting linac.
E.Sargsyan for the ESS NC Linac collaboration team

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO043

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO045

Tuning Esperience on the ESS DTL Cold Model

784

F. Grespan, A. Baldo, P. Bottin, G.S. Mauro, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P. Mereu, M. Mezzano
INFN-Torino, Torino, Italy

An aluminum model of the ESS DTL tank 2 has been delivered to INFN-LNL in december 2017. The tank is 7.1 m long, equipped with movable tuners and movable post couplers. The purpose of this DTL model is to verify the RF design choices (in particular on the first 2 tanks where the Post coupler distribution is irregular) as well as implement and debug algorithms and procedure for stabilization and tuning. The preparatory simulation work and the results of measurements campaign are here presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO045

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO046

Status of the FAIR Proton Linac

787

C.M. Kleffner, S. Appel, R. Berezov, J. Fils, P. Forck, M. Kaiser, K. Knie, C. Mühle, S. Puetz, A. Schnase, G. Schreiber, A. Seibel, T. Sieber, V. Srinivasan, J. Trüller, W. Vinzenz, C. Will
GSI, Darmstadt, Germany
A. Almomani, H. Hähnel, U. Ratzinger, M. Schuett, M. Syha
IAP, Frankfurt am Main, Germany

As part of the accelerator chain for antiproton production of the FAIR facility, a special high-intensity short pulsed 325 MHz proton linac is being developed. The Proton linac is designed to deliver a beam current of 70 mA with an energy of 68 MeV. A 2.45 GHz ECR source designed for the generation of 100 mA beams with an energy of 95 keV is currently being tested at CEA/Saclay. The production of the structure of the IAP ladder RFQ is nearly completed. First parts of the RFQ vacuum chambers have been successfully copperplated at the GSI. Seven Thales Klystrons have been delivered to GSI at the beginning of 2018 and are nearly ready for use. The completion of the setup of the HV modulator is expected end of the year 2018. The state of procurement and development of further accelerator components will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO046

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO047

SPIRAL2 Injector Commissioning

790

THOP01

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R. Ferdinand, M. Di Giacomo, H. Franberg, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle, F. Varenne
GANIL, Caen, France
D. Uriot
CEA/DRF/IRFU, Gif-sur-Yvette, France

The SPIRAL2 injector is composed of two ion sources (p/d and heavy ions up to A/Q=3) followed by a 730 keV/u RFQ. Beam commissioning has started in 2014 in parallel with the superconducting linac and HEBT installations. The RFQ beam commissioning started soon after the first RF conditioning done in October 2015. This paper describes the RFQ beam measurements done on the diagnostic plate for the reference particles (H⁺, 4He2+ and recently 18O6+) and the difficulties encountered for the RFQ commissioning at the A/Q=3 field level.

Slides THPO047 [7.846 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO047

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO048

Low Power Measurement of a 1300-MHz RFQ Cold Model

794

THOP02

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Y. Kondo, T. Morishita, J. Tamura
JAEA/J-PARC, Tokai-mura, Japan
M. Otani
KEK, Ibaraki, Japan

Funding: This work is supported by JSPS KAKENHI Grant Number 17K18784.
A muon linac development for a new muon g-2/EDM experiment is now going on at J-PARC. Muons from the muon beam line (H-line) of the J-PARC muon facility are once stopped in a silica aerojel target and room temperature muoniums are evaporated from the aerogel. They are dissociated with the lasers to be the ultra slow muons, then accelerated up to 212 MeV using a linear accelerator. The low energy part of this muon linac consists of a 324-MHz RFQ and an IH DTL. The frequency is increased to 1296 MHz at the following CCL section. We propose to replace the low energy section to a 1300-MHz RFQ to simplify the configuration of the muon linac. The 1300-MHz RFQ will be extremely small compared to conventional RFQs, therefore we made a cold model to proof the feasibility of this scheme. In this paper, the result of low-power measurement of the 1300-MHz RFQ cold model is described.

Slides THPO048 [2.160 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO048

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO049

Field Tuning of a Radio-frequency Quadrupole Using Full 3D Modeling

798

T. Morishita, K. Hasegawa, Y. Kondo, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Otani
KEK, Ibaraki, Japan

The radio-frequency quadrupole linac (RFQ) is operating in the frontend of the J-PARC linac to accelerates 50 mA negative hydrogen beams from 0.05 MeV to 3 MeV. As a backup, the spare RFQ has been fabricated in 2018. The vane-voltage ramping is adopted to improve the acceleration efficiency so that the cross-sectional shape is adjusted longitudinally to produce the designed voltage distribution. Then, the three-dimensional cavity models including modulations and cutbacks were created in CST Micro-Wave Studio. The vane-base widths and cutback depths were optimized to produce the desired vane-voltage distribution. In the final tuning, the heights of the stub turners were also determined based on the tuner responses obtained from the full 3D models. In this paper, the detailed design process of the cavity dimensions and the result of the low-power measurements are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO049

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO050

Research on the New Cavity Structure of RFQ Accelerator With Bent Vanes at IMP

802

THOP03

use link to see paper's listing under its alternate paper code

L. Yang, T. He, Y. He, C.X. Li, L. Lu, L.P. Sun, C.C. Xing
IMP/CAS, Lanzhou, People’s Republic of China
L. Yang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

A new cavity structure of RFQ accelerator with bent vanes is proposed to meet the miniaturization requirement of low frequency heavy ion accelerators at Institute of Modern Physics (IMP), Chinese Academy of Sciences. The new structure has a downsized cross section by bending vanes while keeping a certain vane lengths. It also possesses the advantages of simple cooling structure and high power efficient when used in low frequency. The new structure has obvious advantages in reducing manufacturing difficulty of cavity, cutting down project cost, enhancing facility reliability and stability.

Slides THPO050 [1.407 MB]

Poster THPO050 [0.398 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO050

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO051

The Multi-physics Analysis of LEAF RFQ

805

X.B. Xu, T. He, Y. He, C.X. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, C.C. Xing, L. Yang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

The 81.25 MHz CW RFQ is designed to accelerate heavy ions with Q/A from 1/7 to 1/2 at 0.5 MeV/u for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). The four-vane RFQ consists of six mod-ules with a total length of 5.95 meters, For the CW oper-ating mode, thermal management will be a very important issue, Therefore a multi-physics analysis is necessary to ensure that the cavity can stably operate at the high RF power . The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and the frequency shift, the cooling water system is used for frequency tunning by the temperature adjustment, and also analyze RFQ undercuts, fixed tuners, and pi-mode rods, the results show that the thermal and structural design of this RFQ is reasonable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO051

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paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO052

High Power Test of the LEAF-RFQ

808

L. Lu, Y. He, W. Ma, L.B. Shi, L.T. Sun, L.P. Sun, L. Yang, Y. Yang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

High power heavy ion drivers require a CW low-frequency accelerator for initial acceleration. A CW four-vane radio frequency quadrupole (RFQ) accelerator is designed to accelerate heavy ions A/q up to 7 from 14 keV/u to 500 keV/u, as a new injector for the Low Energy Accelerator Facility (LEAF) at Institute of Modern Physics (IMP). The measurements of low power test were reported previously. In this paper, the results of high power test of the RFQ, including the test of the acceleration systems and beam profiles, will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO052

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paper received ※ 07 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO053

Status of the China Material Irradiation Facility RFQ

811

C.X. Li, W.L. Chen, W.P. Dou, Z. Gao, Y. He, G. Huang, C.L. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, F.F. Wang, W.B. Wang, Z.J. Wang, Q. Wu, X.B. Xu, L. Yang, P.Y. Yu, B. Zhang, J.H. Zhang, P. Zhang, T.M. Zhu
IMP/CAS, Lanzhou, People’s Republic of China

Funding: Supported by the National Magnetic Confinement Fusion Science Program of China (Grant No.2014GB104001) and the National Natural Science Foundation of China (Grant No.91426303).
The pulsed high power test and beam test of the China Material Irradiation Facility RFQ have been implemented. Before this, the radio frequency measurements and tuning are performed. In this paper, the processes and results of the radio frequency measurements, tuning, pulsed high power test and beam test will be presented. The results of tests are in good agreement with the design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO053

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO054

Recent Progress of a CW 4-rod RFQ for the SSC-LINAC

814

Z.S. Li, Y. Cong, H. Du, Y. He, L. Jing, Q.Y. Kong, X.N. Li, J. Meng, G.D. Shen, K.D. Wang, Z.J. Wang, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, W.J. Xie, Z. Xu, J.C. Yang, Y.Q. Yang, X. Yin, Y.J. Yuan, Y. Zhang
IMP/CAS, Lanzhou, People’s Republic of China
Y.R. Lu
PKU, Beijing, People’s Republic of China

The SSC-LINAC is under design and construction as a linear injector for the Separated-Sector Cyclotron (SSC) of the Heavy Ion Research Facility at Lanzhou (HIRFL). The continuous-wave (CW) 4-rod radio-frequency quad-rupole (RFQ) of the SSC-LINAC has important progress in past years. In the autumn of 2016, the cavity has been operated with 35 kW on CW mode in automatic RF con-trolled mode during RF power commissioning, which is needed to accelerate 238U³⁴⁺ beams. The beam transmis-sion efficiency, transverse emittance and energy spread has been obtained in beam commissioning. In this paper, the results of experiments will be presented and discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO054

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO057

Redesign of CERN Linac3 RFQ for Lead 29+

818

S. Benedetti, G. Bellodi, J.-B. Lallement, A.M. Lombardi
CERN, Geneva, Switzerland

CERN Linac3 is at the start of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates 208Pb²⁹⁺, though in recent years runs were performed with 40Ar¹¹⁺ and 129Xe²²⁺, in view of the increasing interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for 208Pb²⁵⁺, the lower beam rigidity of the heavy ions currently in use and planned for the future permits a redesign of the RFQ optics aimed at increasing its transverse acceptance, and thus the transmitted beam current. A study of this has been performed, and the methodology adopted and the results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO057

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paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO058

RF Design of a High-frequency RFQ Linac for PIXE Analysis

822

SPWR016

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THOP04

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H.W. Pommerenke, A. Bilton, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins, M. Vretenar
CERN, Geneva, Switzerland
H.W. Pommerenke, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: This work has been sponsored by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E12CHA).
Protons with an energy of few MeV are commonly used for Ion Beam Analysis of materials, in particular with the Proton Induced X-ray Emission technique (PIXE). Because of its non-damaging character, PIXE is used in a variety of fields, in particular for the diagnosis of cultural heritage artwork. A compact accelerator based on a high frequency RFQ (Radio Frequency Quadrupole) linac has been designed and is being built at CERN. The length of the RFQ is only one meter and it allows the acceleration of a proton beam up to an energy of 2 MeV. The complete system is conceived to be transportable, allowing PIXE analysis almost anywhere. This paper covers the RF design of the compact RFQ operating at 750 MHz. We present general accelerator parameters and the current state of the RF design, which includes RFQ geometry and coupler design, thermal simulation and first particle tracking results.

Slides THPO058 [2.404 MB]

Poster THPO058 [2.192 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO058

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO060

First RF Measurements of the 325 MHz Ladder RFQ

826

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 prototype Ladder-RFQ features a very constant voltage along the axis. The RFQ was high power tested at the GSI test stand. It accepted 3 times the RF power level 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 higher symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. For the present design duty cycles are feasible up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in August 2018. We will show the the finalization of manufacturing as well as first low level RF measurements of the Ladder RFQ.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO060

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO061

Beam Characterization of the MYRRHA-RFQ

830

SPWR017

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P.P. Schneider, M. Droba, O. Meusel, H. Podlech, A. Schempp
IAP, Frankfurt am Main, Germany
D. Noll
CERN, Geneva, Switzerland

Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and HORIZON 2020 for the MYRRHA project #662186 and HIC for FAIR.
The Linear Accelerator for the MYRRHA project* is under construction. In a first step the linac up to 100 MeV will be realized. The LEBT section has been set into operation in Belgium and the RFQ is installed in summer 2018. A system to analyze the ion beam consisting of a slit-grid emittance scanner, a beam dump and a momentum spectrometer, called diagnostic train descripted in **, will be set on the rails to characterize the beam at the RFQ injection point. The results will be used to adjust the optimal matching for the RFQ. After the measurements downstream the LEBT, the diagnostic train begins its journey along the beam line and at the first station the RFQ is installed. The accelerated beam of the RFQ is then analyzed and optimized. In addition to optimization of transmission the artificial production of beam offsets in the LEBT is of special interest. These will be measured at the injection point to estimate the range of possible offsets. In the following measurements these offsets will be used to study the influence of the offsets on the RFQ performance. Furthermore, the RFQ parameters are varied to see their influence on the beam transport, transmission and beam quality.
* H.Aı̈t Abderrahim et al. "MYRRHA: A multipurpose accelerator driven system for research & development", 2001
** 1st Experiments at the CW-Operated RFQ for Intense Proton Beams, LINAC16

Poster THPO061 [4.610 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO061

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO062

IFMIF/EVEDA RFQ Preliminary Beam Characterization

834

E. Fagotti, L. Antoniazzi, L. Bellan, M. Comunian, F. Grespanpresenter, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo
INFN/LNL, Legnaro (PD), Italy
T. Akagi, K. Kondo, K. Sakamoto, T. Shinya, M. Sugimoto
QST, Aomori, Japan
P. Cara
IFMIF/EVEDA, Rokkasho, Japan
H. Dzitko, I.M. Moya
F4E, Germany
R. Heidinger, A. Marqueta
Fusion for Energy, Garching, Germany
I. Podadera
CIEMAT, Madrid, Spain

The IFMIF/EVEDA RFQ is the longest and powerful operated. Therefore, it requires a careful characterization from several aspects: beam dynamics, RF, mechanics, installation and commissioning. Due to the very large power handling, the preliminary beam operation was decided to be performed with a low proton beam current at one half of the voltage needed for deuteron accelera-tion, i.e. from 8 mA to 30 mA at 2.5 MeV in pulsed mode, with respect to the nominal 130-mA deuteron beam at 5 MeV in CW. In this framework, it will be presented the characterization of the RFQ in terms of simulation and measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO062

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO064

Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility

838

X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China
B.C. Wang, Z.M. Wang, C. Zhao
NINT, Shannxi, People’s Republic of China

This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi’an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H⁻ beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 μs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode com-ponent is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning.

Poster THPO064 [1.413 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO066

First High Power Test of the ESS High Beta Elliptical Cavity

841

THOP05

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H. Li, L. Hermansson, M. Jobs, R.J.M.Y. Ruber, R. Santiago Kern
Uppsala University, Uppsala, Sweden
G. Devanz, T. Hamelin
CEA/DSM/IRFU, France

ESS, the European Spallation Source, will adopt elliptical multi-cell superconducting cavities with a beta value of 0.86 to accelerate the proton beam up to 2 GeV at the last section of the linac. A 5-cell high-beta cavity for ESS project was tested with high power at FREIA Laboratory. A pulse mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involved a 5-cell elliptical cavity, a fundamental power coupler, a cold tuning system, LLRF system and a RF station. These tests represented an important verification before the series production. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.

Slides THPO066 [1.437 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO066

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paper received ※ 14 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO067

Control System and Experiment for RAON HWR Cryomodules

845

H. Kim, J.W. Choi, C.O. Choi, H. Jang, Y.W. Jo, H.C. Jung, Y. Jung, J.W. Kim, M.S. Kim, Y. Kim, D.Y. Lee, M. Lee, S. Lee, K.T. Seol, K.T. Son
IBS, Daejeon, Republic of Korea

A prototype of half-wave resonator (HWR) cryomodules is fabricated and tested. Cables and tray are installed for horizontal test. The design and the piping and instrumentation diagram (P&ID) of the HWR cryomodule are presented. The HWR cryomodule is tested with developed programmable logic controller (PLC) and experimental physics and industrial control system (EPICS) control systems. The heat loads of the HWR cryomodule for static and dynamic are measured.

Poster THPO067 [0.631 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO067

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO068

AN Effect of Field Emission on Low Beta Superconducting Cavities

849

SPWR011

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X. Liu, Z. Gao, Y. He, G. Huang
IMP/CAS, Lanzhou, People’s Republic of China

Superconducting RF (SRF) technology is widely ap-plied in particle accelerators to shorten the accelerator length and lower the construction price due to its high acceleration gradients with low rf losses. Field emission is the chief limitation associated with the surface electric field which will finally determine the cavity performance during the operation. The pickup-drop signal caused by field emission seriously affect the stable operation of the superconducting linac in the Chinese initiative Accelera-tor-Driven Sub-critical System (CiADS) demon facility. Simulations of the field emission effect and experimental measurements of the pickup-drop signal have been per-formed on the half wavelength resonator (HWR) cavity. And a modified design of the pickup antenna will be discussed to solve the pickup-drop problem.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO068

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paper received ※ 12 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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THPO069

The Electromagnetic Optimization of TE-sample Host Cavity at IMP

852

S.C. Huang, Y. He, T. Tan, S.X. Zhang
IMP/CAS, Lanzhou, People’s Republic of China

As a part of the research and development work of thin-film materials for superconducting radio frequency(SRF) application in future accelerators at IMP, a 3.9GHz TE sample host cavity is being developed for the purpose of characterizing the RF Property and the loss mechanism of thin-film materials, which operates in the TE011 mode and accommodates disk sample with 110mm diameter, theoretically, the maximum magnetic field on sample surface will go up to 100mT, the resolution of surface resistance on sample will below nOhm by using thermometry technique( T-Mapping). In this paper, the electromagnetic optimization result of TE-sample host cavity will be presented, and the design consideration of hook tip style coupler and T-mapping system are also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO069

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO072

Cryogenic Tests of the Superconducting β=0.069 CH-cavities for the HELIAC-project

855

SPWR010

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

In the future the existing UNILAC (UNIversal Linear Accelerator) at GSI will be most exclusively used as an injector for FAIR to provide short pulse high intensity heavy ion beams at low repetition rates [Barth3]. A new superconducting (sc) continuous wave (cw) high intensity heavy ion Linac should provide ion beams with max. duty factor above the coulomb barrier for the Super Heavy Element (SHE) program at GSI. The fundamental Linac design comprises a low energy beam transport (LEBT)-section followed by a sc Drift Tube Linac (DTL) consisting of sc Crossbar-H-mode (CH) structures for acceleration up to 7.3 MeV/u [*]. After the successful test and commissioning of the first demonstrator section with heavy ion beam from the HLI in 2017 [**], the next two sc CH-structures have been constructed and the first one has been extensively tested at cryogenic temperatures at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of the final cold test of the first CH-structure as well as the next steps realizing a new sc cw heavy ion LINAC at GSI will be presented.
[*]W. Barth et al., "Further investigations for a superconducting cw-Linac at GSI"
[**]W. Barth et al., "First high intensity heavy ion beam tests with a superconducting multi gap CH-cavity"

Poster THPO072 [1.150 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO072

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO073

RF Commissioning of the Superconducting 217 MHz CH Cavity for Heavy Ions and First Beam Operation

859

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

Future research programs at GSI in the field super heavy element (SHE) synthesis require high intense heavy ion beams above the coulomb barrier and high average particle currents. The upcoming demands exceed the technical opportunities of the existing UNIversal Linear ACcelerator (UNILAC). Consequently, a new dedicated superconducting (sc) continuous wave (cw) linac is crucial to keep the SHE research program at GSI competitive on a high level. Recently the first linac section, serving as a prototype to demonstrate the reliable operability of 217 MHz multi gap crossbar-H-mode (CH) cavities under a realistic accelerator environment, has been extensively tested with a heavy ion beam delivered from the GSI High Charge State Injector (HLI). Fulfilling its role as a key component of the whole demonstrator setup. The first sc 217 MHz CH cavity (CH⁰) successfully accelerated heavy ions up to the design beam energy and even beyond at high beam intensities and full transmission. In this contribution the rf commissioning and the first beam operation of the cavity is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO073

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO076

Multiphysics Design Studies of a Superconducting Quarter-wave Resonator at Peking University

863

M. Chen, S. Chen, A.Q. Cheng, W. Cheng, J.K. Hao, S.W. Quan, F. Zhu
PKU, Beijing, People’s Republic of China

Funding: This work is supported by National Basic Research Program (2014CB845504)
A 81.25MHz, geometric β=0.046 quarter-wave resonator has been designed and analysed at Peking University. This paper mainly presents the multi-physics studies of this cavity, include electromagnetic design, mechanical analysis and multipacting simulation, to predict its behaviour under practical operating process. Various transverse vibration modes of inner conductor were found under different fixed conditions and an asymmetric shorting plate was adopted to avoid high possibility of multipacting
"quarter-wave resonator"
"multiphysics"
"multipacting"
"frequency detuning"
"stiffening design"

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO076

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paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO079

RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations

866

THOP10

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V.V. Paramonov
RAS/INR, Moscow, Russia
K. Flöttmann
DESY, Hamburg, Germany

For diagnostic of longitudinal distribution of electrons in unique REGAE bunches is applied a specially developed deflecting structure with minimized level of aberrations in the field distribution and improved RF efficiency. Short deflecting cavity was constructed and installed now in REGAE beam line. The cavity is tested at operational level of RF power. The main distinctive features of the cavity are mentioned and obtained results are reported.

Slides THPO079 [1.803 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO080

Design Validation of a Chopping and Deflecting System for the High Current Injector at IUAC

869

S. Kedia, R. Ahuja, R. Kumar, R. Mehta
IUAC, New Delhi, India

A chopping and deflecting system has been designed and developed to provide the chopped beam with various repetition rates at the IUAC experimental facilities. It consists of four pairs of deflecting plates with increasing gap from 15 mm to 21 mm to maximize the effective electric field, preserve the beam emittance and to maximize the transmission efficiency within the same voltage conditions. The design of CDS has been validated with various simulation codes like CST MWS, Solid Works, Python and TRACE 3D. The deflecting plates have been fabricated, and assembled with in the design accuracy of 100 microns. A vacuum chamber has been designed and fabricated to incorporate the deflector plate assembly. The CDS unit has been installed in the Low Energy Ion Beam Facility at the IUAC to validate the design value of ion beam deflection. A slit has been installed to cut the deflected charge particles. Since the pulse power electronics required for chopping is presently under design we have used DC voltage across the four pairs of deflecting plates and amount of deflection was measured accordingly. The design, development, and DC beam test will be discussed in the article.

Poster THPO080 [2.037 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO080

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO082

Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement

872

SPWR028

use link to see paper's listing under its alternate paper code

J. Bai, Q.S. Chenpresenter, K. Fan
HUST, Wuhan, People’s Republic of China

Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.

Poster THPO082 [0.484 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO083

Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro

875

G. Kourkafas, T. Kamps, A. Neumann
HZB, Berlin, Germany
B. Keune
RI Research Instruments GmbH, Bergisch Gladbach, Germany

The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these ambitious goals necessitates a thorough determination of the bunch parameters after the first acceleration stages, namely the photoinjector and the succeeding booster module. For the measurement of primarily the bunch duration and subsequently the longitudinal phase space and transverse slice emittance, a single-cell 1.3-GHz TM110-like mode vertically deflecting cavity was manufactured by RI Research Instruments GmbH, following the respective design developed for the Cornell ERL injector. This article summarizes the design parameters, manufacturing procedure and testing of this pulsed RF resonator, together with the expected temporal measurement resolution for the nominal beam energies at the initial acceleration stages of BERLinPro.

Poster THPO083 [1.396 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO083

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO084

BPM Time of Flight Measurements for Setting-up the RF Cavities of the CERN Linac4

879

M. Bozzolan
CERN, Geneva, Switzerland

The newly constructed H⁻ LINAC4 at CERN has recently completed its first extended reliability run. It is equipped with Beam Position Monitors (BPMs) based on shorted-stripline pick-up electrodes to measure both position and Time of Flight (ToF). The ToF, in turn used to calculate the kinetic energy of the beam, is determined through signal phase shift measurements between pairs of BPMs. ToF measurements are performed by scanning of the phase of the RF injected into the cavities to find the nominal RF settings for optimal beam acceleration. This paper focuses on the technical aspects of the ToF measurement as well as on the results obtained during beam commissioning and their comparison with beam dynamics simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO084

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paper received ※ 12 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO086

Beam Loss and Average Beam Current Measurements Using a CWCT

882

F. Stulle, H. Bayle, J.F. Bergoz, T. Delaviere, L. Dupuy
BERGOZ Instrumentation, Saint Genis Pouilly, France
P. Forck, M. Witthaus
GSI, Darmstadt, Germany
D. Vandeplassche
SCK•CEN, Mol, Belgium
J.X. Wu
IMP/CAS, Lanzhou, People’s Republic of China

The CWCT is a novel instrument adapted to an accurate average current determination of bunched CW beams or macro pulses. By combining a high-droop current transformer with novel electronics for signal analysis, an output signal bandwidth of DC to about 500kHz and a current resolution down to the micro-ampere level are achieved. Beam current fluctuations are followed within microseconds, permitting fast detection of beam loss. These characteristics render the CWCT an ideal instrument for HPPAs, for example ADS linacs, and other proton or ion accelerators. We present the CWCT principle and the CWCT performance achieved in beam experiments at UNILAC, GSI.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO086

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO090

The Analysis of Module Failure in High Solid-state Amplifier for High Current RFQ

886

L.P. Sun, Y. He, G. Huang, C.X. Li, L. Lu, A. Shi, L.B. Shi, X.B. Xu, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

New accelerator RF system was upgraded to the solid-state amplifier in ADS project due to its stable, sustainable and reliable. Until now, newest 80kW SSA was adopted in IMP, operating in 162.5MHz, and over 120 power modules were combined through several synthesizers for 80kW output. but since too many modules were optimized for amplitude and phase in the same time, one or some failure of circulator will lead to injure of whole RF system, when wavelength meets a specific condition, injure would turn out severe accident and heavy loss. In this paper, analyzing and simulating the multi-level synthetic matrix was the important method for ADS accident happened in June 20. 2017, the failure simulated results for RF amplify links under the specific circumstances also was presented simultaneously.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO090

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paper received ※ 17 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019

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THPO091

90 kW Solid-state RF Amplifier with a TE011-mode Cavity Power-combiner at 476 MHz

889

THOP07

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Y. Otake, T. Asaka, T. Inagaki
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
S. Aizawa, K. Nagatsuka, T. Okuyama, K. Sato, H. Yamada
Nihon Koshuha Co. Ltd, Yokohama, Japan

Solid-state RF amplifiers, which have long lifetimes and small failures, are the recent trend of reliable and stable high-power rf sources for particle accelerators. Hence, we designed a 90kW solid-state amplifier with an extreme low-loss TE011 mode cavity (Q0=100, 000) power-combiner operated at 476 MHz and a 6 us pulse width. Developing this amplifier is for replacement of an IOT rf amplifier, at the X-ray free-electron laser, SACLA. In SACLA, highly RF phase and amplitude stabilities of less than 0.02 deg. and 10^-4 in rms are necessary to stable lasing within a 10 % intensity fluctuation. The amplifier comprises a drive amplifier, a reentrant cavity rf power divider, 100 final amplifiers with a 1 kW output each and a TE011 mode cavity combiner. Water-cooling within 10 mK and a DC power supply with a noise of less than -100 dBV at 10 Hz for the amplifier is necessary to realize the previously mentioned stabilities. Based on the test results of the amplifier, the above-mentioned specifications with the extreme low-loss are promising. The amplifier also allows us to operate in pulsed and CW rfs for linacs and ring accelerators. We report the performance of the 90kW amplifier.

Slides THPO091 [1.750 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO091

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paper received ※ 06 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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THPO092

LCLSII Fundamental Power Coupler Manufacturing Status and Lesson Learned

893

S. Sierra, G. Garcin, Ch.L. Lievin, G. Vignette, I. Yao Leclerc
TED, Velizy-Villacoublay, France
M. Knaak, M. Pekeler
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Thales and RI Research Instrument have manufactured and assembled half of the power couplers for the LCLSII project. This paper remains main characteristics of these coupler. It will also describe main challenges that were overcome among them, thickness of copper coating on Warm Internal Conductor at 150µm and lessons learned during the manufacturing phase of these couplers. The paper will also propose some possible optimization for a future mass production of such components and parameters which could be relevant for a better understanding link to the statistic results obtained.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO092

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paper received ※ 10 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO093

Status and Results Obtained on a RF Conditioning Test Bench for 704 MHz Couplers in the Frame of ESS Project

895

S. Sierra, Y. Amal, Ch.L. Lievin, I. Yao Leclerc
TED, Velizy-Villacoublay, France
M.E. Chahbazian, J.G. De_Oliveira, A.G. Goeury, L.J. Nennig, S.P. Petitjean
GERAC Thales, Le Barp, France

Thales and Gerac are developing a test bench able to make the RF conditioning of the Fundamental Power Couplers at 704 MHz in the frame of the ESS project for CEA. The status of the developments of the test bench is described including the modulator, klystron and all relative equipments. The paper will also describes the results obtained at the date of presentation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO093

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paper received ※ 10 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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THPO095

Present Status of Capacitor-charging Power Supplies for Klystron Modulators in SuperKEKB Injector Linac

898

M. Kawamura, M. Akemoto, S. Fukuda, H. Honma, S. Michizono, H. Nakajima, T. Natsui, T. Shidara
KEK, Ibaraki, Japan
H. Akikawa, O. Endo, K. Sato
Nihon Koshuha Co. Ltd, Yokohama, Japan

The capacitor-charging power supplies (CCPSs) for the klystron modulators have been developed from 2002 in the SuperKEKB injector linac. The specifications are that the output voltage is 43kV, the charging power is 30kJ/s, and the output voltage stability is 0.2%p-p. Being used in the old facility, their sizes are restricted in 480mm x 680 mm x 760mm. After various modifications, the 13 CCPSs in the linac have been operated with no fault since last October. The present status of the CCPSs, including the outlines, specifications, and the modifications against the faults, are described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO095

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO096

Design Study of a High Efficiency Klystron for SuperKEKB Linac

901

F. Qiu, S. Fukuda, S. Matsumoto, T. Matsumoto, T. Miura, T. Natsui
KEK, Ibaraki, Japan

The injector linear accelerator (linac) for the SuperKEKB particle accelerator requires a higher efficiency klystron than the currently used 50 MW, S-band, pulsed unit (PV3050/E3730), which operates at the same voltage, to increase the power redundancy. The efficiency is expected to improve from the currently observed 45% to more than 60%. We propose a type of high efficiency klystron using novel bunching mechanisms. The 1-D disk model based code is used for preliminary optimization of the tube parameters; these parameters are further checked by 2-D codes known as field charge interaction (FCI) and MAGIC. In this paper, the design consideration of the high efficiency klystron is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO096

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO097

Recent Results for Study of Ceramic and Copper Plating for Power Couplers

905

Y. Yamamoto, E. Kako, S. Michizono
KEK, Ibaraki, Japan
E. Cenni
CEA/IRFU, Gif-sur-Yvette, France
A. Four
CEA/DRF/IRFU, Gif-sur-Yvette, France
Y. Okii
Nomura Plating Co, Ltd., Osaka, Japan

KEK has conducted a survey to select an optimum ceramic after withdrawal by a domestic manufacturing company two years ago. For this selection, there are four important items on the properties of ceramic; that is, relative permittivity, dielectric loss tangent, surface and volume resistance, and secondary electron emission coefficient. For measurements of these parameters, five kinds of ceramic samples supplied from three companies were measured using three kinds of measurement systems. For measurement of secondary electron emission, scanning electron microscope (SEM) with beam blanking system was used. On the other hand, residual resistivity ratio (RRR) for copper plating, which is the most important item for quality control, has also been carried out while changing plating thickness and acid temperature. In this report, the recent results for these studies will be presented in detailed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO097

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO100

Development of a 1.5 GHz High-power CW Magnetron for SRF Accelerator

908

L. Wenliang
College of Engineering and Applied Sciences for Nanjing University, Nanjing, People’s Republic of China
S. An, Y.J. Ke, S. Lingbin, Z. Pengjiao, L. Youchun, L. Zhao, B.Z. Zhou
PLAI, Nanjing, People’s Republic of China
J.Z. Li, L.P. Zhang, Hou, R. Rui
ADS, Jiangsu Province, People’s Republic of China

An 1.5 GHz, 13.5 kW CW high-power magnetron for a superconducting RF accelerator has been developed by Andesun Technology Group Co., Ltd. with Nanjing Sanle Electronic Information Industry Group Co., Ltd., in order to replace the klystron, that could reduce the power source cost to about one-third. The cavity, output power antenna and coupling door-nob have been optimized by using CST Studio. Testing results have shown that the resonance frequency and output power have met the requirements, and the efficiency of the magnetron is higher that 78.45%.

Poster THPO100 [0.574 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO100

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO102

Design Studies of Output Window for CEPC Klystron

911

Z.J. Lu, Y.L. Chi, S. Fukuda, G. Pei, S. Pei, S.C. Wang, O. Xiao, U. N. Zaib, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
S. Fukuda
KEK, Ibaraki, Japan

A high power and high efficiency klystron of the 650MHz, 800kW CW klystron for the Circular Electron Positron Collider (CEPC) is designed and developed at IHEP. This paper presents the design and simulation for the high power coaxial window for it. Plan of the hot test (high power testing before installing to the klystron) are also described. Simulation software of CST, ANSYS and Multipac 2.1 are used for design of window microwave structure, thermal analysis and multipacting effects. We obtained the good simulation results successively; the coaxial window S-parameter analysis, has revealed a low reflection at the operating frequency of 650 MHz. The thermal simulation shows a good temperature distribution under the cw 800kW propagation; maximum temperature has been found to be 33 °C at ceramic with water cooling in the inner and outer conductor. The multipacting at the window is possible source of the failure and it is shown that multipacting has less chance to be happened on the surface of ceramic.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO102

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paper received ※ 12 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019

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THPO103

Application of Solid State Amplifiers in ADS Project at IHEP

914

O. Xiao
Institute of High Energy Physics (IHEP), People’s Republic of China
Y.L. Chi, N. Gan, X. Ma, Z.S. Zhou
IHEP, Beijing, People’s Republic of China

The solid state amplifier is an important part of the RF power source system of ADS project at IHEP. Three kinds of solid state amplifier with different power and frequency have been applied. In this paper, the specifications of solid state amplifier are presented. In addition, the principle of breakdown of power modules during the high power test of coupler are analyzed.

Poster THPO103 [0.195 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO103

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paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO104

Development of 150.4MHz Continuous Wave Solid-state Amplifier

917

L. Zhao
Nanjing University of Aeronautics and Astronautics, Jiangning, People’s Republic of China
S. An, Y.J. Ke, Z. Pengjiao, L. Wenliang, B.Z. Zhou
PLAI, Nanjing, People’s Republic of China

A 150.4MHz to 155.4MHz, 300W continuous wave solid-state amplifier as an accelerator power source has been developed by us. In order to increase the lifetime of MOSFET and meet the requirements of every parameters, Drain voltage and quiescent current is set at a better point with a well-designed heat dissipation structure, we make the solid state amplifier stable in performance. Taking the microwave leakage into account, the chassis structure is optimized and designed, and the microwave absorption device is adopted to make the structure compact, protect other parts not affected by the microwave leakage. After the assembly is completed, the working parameters meet the design requirements very well. The MOSFET flange temperature and output parameters meet the design requirements.

Poster THPO104 [1.405 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO104

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO107

High Power Coupler R&D for Superconducting CH-cavities

920

SPWR025

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

The upcoming demands of the future research programs at GSI exceed the technical opportunities of the existing UNIversal Linear ACcelerator (UNILAC). Besides, the machine will be exclusively used as an injector for FAIR (Facility for Antiproton and Ion Research) providing high power heavy ion beams at a low repetition rate for injection into the synchrotron. A new dedicated superconducting (sc) continuous wave (cw) Linac is crucial to keep the research program competitive. The first part of the cw-linac, comprising a 217 MHz multi gap Crossbar-H-mode (CH) cavity surrounded by two sc solenoids inside a cryostat, already served as a prototype demonstrating reliable operability in a realistic accelerator environment. A sufficient high power RF-coupling concept is needed to feed this newly developed cw-RF cavity with up to 5 kW of RF-power. A high power coupler test stand was recently built to provide for a testing environment; further upgrade measures of this test area are foreseen. This contribution deals with the recent coupler R&D for the demonstrator set up. Besides simulations of thermal losses at the coupler (inside the RF-cavity) will be shown as well.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO107

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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THPO108

Development of an High Gradient Side Coupled Cavity for PROBE

924

THOP08

use link to see paper's listing under its alternate paper code

S. Pitman, R. Apsimonpresenter, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N. Catalán Lasheras, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland
H.L. Owen
UMAN, Manchester, United Kingdom

The PROBE project aims to develop a high gradient proton accelerator for protons with energy around 250-350 MeV for proton radiography. Detailed studies have shown that the optimum design is a side coupled cavity at S-band. With an aperture of 8 mm a gradient of 54 MV/m can be obtained with 13 MW of RF power in a 30 cm structure. A prototype cavity has been machined by VDL and diffusion bonded by Bodycote. We present initial measurements of the prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO108

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paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO109

A New Spherical Pulse Compressor Working with Degenerated "Whispering Gallery" Mode

928

SPWR023

use link to see paper's listing under its alternate paper code

THOP09

use link to see paper's listing under its alternate paper code

Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People’s Republic of China
A. Grudiev
CERN, Geneva, Switzerland

CLIC is focusing on the Compact Linear Collider. To obtain a relatively high accelerating gradient, CLIC utilizes Pulse Compressors to increase the input power of accelerators. This work is to make an alternative design for CLIC pulse compression scheme. There are several kinds of pulse compressor: SLED, BOC, SLED-Ⅱ, spherical pulse compressor and so on. Usually, a spherical cavity, including BOC, can offer a higher Q factor compared with a cylindrical cavity. This design utilizes a spherical cavity working with degenerated Whispering Gallery mode.

Slides THPO109 [1.738 MB]

Poster THPO109 [1.913 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO109

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paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO111

The Test of RF Breakdowns of CPHS RFQ

931

W.B. Ye, C. Cheng, X. Guan, J. Shi, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China
M.C. Wang
NINT, Shannxi, People’s Republic of China

The high accelerating gradient is significant for a compact linear accelerator, and RF breakdowns is a limitation for the high gradient. This work aims to research RF breakdowns of a 325MHz proton Radio Frequency Quadrupole (RFQ) accelerator of the Compact Pulsed Hadron Source（CPHS）. The breakdown rate (BDR) of the RFQ has been measured. Breakdown waveforms have been recorded, which have been used for counting breakdown time distribution and analyzing the location of RF breakdowns.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO111

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO113

Design of 4 Ampere S-Band Linac Using Slotted Iris Structure for Hom Damping

934

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

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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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO113

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paper received ※ 10 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO115

Consolidation and Extension of the High-gradient LINAC RF Technology at PSI

937

P. Craievich, M. Bopp, H.-H. Braun, A. Citterio, H. Fitze, T. Garvey, T. Kleeb, F. Löhl, F. Marcellini, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, K. Rolli, R. Zennaro
PSI, Villigen PSI, Switzerland

For SwissFEL a novel production process for high-gradient, high-precision C-band accelerating structures had been developed at PSI and was implemented for series production in collaboration with industry. The copper parts of the structures are machined and brazed relying on a ultra-high precision manufacturing process and tight mechanical tolerances; no RF tuning methods are applied during or after production. So far none of the structures of the series production failed during RF power conditioning and operation in the SwissFEL facility. After completing the series production for SwissFEL PSI started collaborations with CERN, ELETTRA and DESY for applying the production process and related know-how to other frequencies, namely S-band (3 GHz) and X-band (12 GHz). This paper gives an overview on the ongoing and planned R\&D activities and results obtained so far.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO115

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paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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THPO116

Space-Charge Dominated Photoemission in High Gradient Photocathode RF Guns

941

THOP11

use link to see paper's listing under its alternate paper code

Y. Chen, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan
DESY Zeuthen, Zeuthen, Germany
H. Chen, Y. C. Du, W.-H. Huang, C.-X. Tang, Q.L. Tian, L.X. Yan
TUB, Beijing, People’s Republic of China
H. De Gersem, E. Gjonaj
TEMF, TU Darmstadt, Darmstadt, Germany
M. Dohlus
DESY, Hamburg, Germany
S. A. Schmid
Institut Theorie Elektromagnetischer Felder, TU Darmstadt, Darmstadt, Germany

The cathode emission physics plays a crucial role in the overall beam dynamics in the gun. Interplays between intricate emission mechanisms in the cathode vicinity strongly influence the cathode quantum efficiency (QE) and the intrinsic emittance. The presence of strong space-charge effects in high gradient RF guns further complicates the emission process. A proper modeling of photoemission and a careful treatment of the space-charge contribution is thus of great necessity to understanding the formation of the beam slice emittance. In this article, emission measurements are carried out using the L-band cesium-telluride photocathode RF gun at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) and the S-band copper photocathode RF gun at Tsinghua University. Following the Dowell model a simple so-called space-charge iteration approach is developed and used to determine the QE through temporal and spatial-dependent electromagnetic fields. An impact of the space-charge cooling on the thermal emittance is presented. Measurement data are shown and discussed in comparisons to preliminary simulation results.

Slides THPO116 [6.249 MB]

Poster THPO116 [3.157 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO116

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paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO117

96Zr Beam Acceleration for Isobar Experiment in RHIC

THOP12

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M. Okamura, E.N. Beebe, S. Ikeda, T. Kanesue, D. Rapariapresenter
BNL, Upton, Long Island, New York, USA
H. Haba
RIKEN Nishina Center, Wako, Japan

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
To investigate chiral magnetic effect, 96Zr and 96Ru beams have been accelerated at relativistic heavy ion collider (RHIC) in Run18 at Brookhaven National Laboratory (BNL). 96Zr and 96Ru beams were provided from electron beam ion source (EBIS) injector and tandem Van de Graaff, repectively. In the presentation, 96zr beam production and acceleration will be reported. The EBIS injector consist of laser ion source, EBIS as a charge breeder, 300 keV/u RFQ and 2 MeV/u IH-DTL. The natural abundance of 96Zr is only 2.8 % and about 50 % is occupied by 90Zr. To obtain sufficient beam current, mass number 96 enriched material was used. Unfortunately, only available form of the enriched material is oxide powder which does not suit for laser ion source target. We have established sintering technique of ZrO2 powder to make a solid piece which can be installed into the laser ion source. The induced singly charged Zr and oxygen were delivered to the EBIS to be ionized further. We have optimized laser irradiation condition, EBIS confinement time, operating condition of the linacs to maximized the performance of the linac based injector. The detailed R&D works will be presented in the conference.

Slides THPO117 [2.920 MB]

Poster THPO117 [4.167 MB]

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THPO118

Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ

945

Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
DESY Zeuthen, Zeuthen, Germany
Q.T. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.

Poster THPO118 [1.521 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118

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paper received ※ 08 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO124

Design of Pulsed HV and RF Combined Gun System Using Gridded Thermionic-Cathode

949

T. Asaka, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
Y. Otake
JASRI, Hyogo, Japan
T. Taniuchi
JASRI/SPring-8, Hyogo-ken, Japan

In recent state-of -arts accelerators like an X-ray free electron laser, the electron beam performance of a linear accelerator demands a low emittance of ~ 2mm mrad. To obtain the low-emittance, such a 500kV thermionic-gun at SACLA and a photocathode rf gun generating 0.5~1MeV electron beams had been developed. Although the photocathode rf gun is compact, it is necessary to prepare a highly stabilized, large and complicated laser system. The 500-kV thermionic-gun of SACLA injector has also to prepare a technically difficult and large high voltage system. Hence, we propose a low-emittance gun system with a low-voltage and grid-loaded 50kV thermionic gun and a 238MHz rf cavity to overcome the complicated difficulty, as extension of the established technology. This system quickly accelerates the electron up to 500keV to preserve the low emittance and to cancel a grid focusing effect by the space charge force of the beam. By using a particle tracking code, we obtained the optimum voltage parameters of the grid and the 238MHz rf for obtaining the above-mentioned low emittance. In this paper, we present a numerical feasibility study to realize the low-emittance gun system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO124

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO125

Runing Status of SRF Gun II at the ELBE Radiation Center

952

R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J.S. Schaber, J. Teichert, H. Vennekate, P.Z. Zwartek
HZDR, Dresden, Germany

Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1 and the Deutsche Forschungsgemeinschaft (DFG) grant XI10⁶/2-1.
As a new electron source with higher brilliance, the second version of the superconducting RF photoinjector (SRF Gun II) has been successfully commissioned at the ELBE Center for High-Power Radiation Sources since 2014. SRF Gun II features an improved 3.5-cell niobium cavity as well as a superconducting solenoid in the same cryomodule. For user operation the SRF Gun II with Mg photocathode successfully generated stable beam with bunch charges up to 200 pC in CW mode, and with sub-ps bunch length. In this presentation the gun’s status and beam parameters will be presented.

Poster THPO125 [1.520 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO125

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO126

Compact H⁺ ECR Ion Source with Pulse Gas Valve

955

SPWR037

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Y. Takeuchi, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan

We are developing a compact ECR H⁺ ion source with pulse gas valve. In the case of high current ion linac, the distance between the ion source and the first accelerating tube such as RFQ must be as short as possible to reduce the space charge effect, while operating in a high electric field a good vacuum condition is desirable. Since hydrogen gas always flows out from ion sources if the plasma chamber is filled with the gas, vacuum pumping systems have to evacuate the gas enough before the first accelerating tube. The pulse gas injection system achieved by a fast piezo gas valve can reduce the gas load on the vacuum evacuation system and is suitable for installing the ion source close to the RFQ.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO126

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paper received ※ 19 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO127

The Effect of Energy Fluctuation on the Multi-bunch Acceleration in E-driven ILC Positron Source

958

M. Kuriki, H. Nagoshi
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Negishi
Iwate University, Morioka, Iwate, Japan
T. Okugi, T. Omori, M. Satoh, Y. Seimiya, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
Y. Sumitomo
LEBRA, Funabashi, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

E-Driven method is a technical backup for positron source for ILC. In the positron source, the positron is generated and accelerated in a multi-bunch format with gaps in a macro-pulse. We employ AM (Amplitude Modulation) to suppress the transient beam-loading, but a small fluctuation is still expected, depending on the compensation accuracy. In this article, the positron yield which is ratio of numbers of positrons over electrons, is evaluated as a function of the compensation accuracy. With this result and the detail investigation of the beam loading compensation accuracy by AM, the positron yield of E-Driven Positron source for ILC is evaluated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO127

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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THPO132

Study of the Electron Beam Transfer Line for the AWAKE RUN II Experiment at CERN

962

SPWR036

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S.Y. Kim, M. Chung
UNIST, Ulsan, Republic of Korea
M. Dayyani
IPM, Tehran, Iran
S. Döbert
CERN, Geneva, Switzerland

Proton Beam-Driven Plasma Wakefield Accelerator (PBD-PWFA) has been actively investigated at CERN within the AWAKE experiments to study the electron beam acceleration using plasma wake fields of the order of GV/m. In the AWAKE RUN 1 experiment an electron beam with an energy of 19 MeV and a bunch length of 2.2 ps rms has been used for the first demonstration of electron beam acceleration in the plasma wake fields. It has been observed that the energy gain of the electron beam is up to 2 GeV, and electron capture efficiency is few percent. Higher capturing efficiency and emittance preservation could be achieved by making the electron beam short enough to be injected only into the acceleration and focusing phase of the plasma wake fields. The electron accelerator needs to be upgraded for AWAKE RUN 2 experiments to obtain a bunch length less than 100 fs which corresponds to a quarter of the plasma wavelength. Planned electron beam parameters for the AWAKE RUN 2 are a beam charge of 100 pC, and a beam energy larger than 50 MeV. In this paper, we show the electron beam parameters for RUN 2, and the parameters of the transfer line such as Twiss parameters, beam envelope, and emittance.
UNIST, Ulsan, 44919, Korea
Institute For Research in Fundamental Sciences, 19395-5531, Tehran, Iran
CERN, Geneva 1211, Switzerland

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO132

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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