SRF2017 - Table of Session: MOPB (Poster Session)

Paper	Title	Page
MOPB001	Concepts and Design for Beamline HOM Dampers for eRHIC	39
	P. Kolb, Y. Gao, D. Holmes, K.S. Smith, W. Xu BNL, Upton, Long Island, New York, USA Y. Gao PKU, Beijing, People's Republic of China
	Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. In the design of eRHIC at BNL, HOM power plays a major role for the SRF installation. Depending on the final accelerator design and choice of cavity, up to 100kW of HOM power is estimated to be generated, presenting a big challenge for the HOM damping concept. Due to this high amount of HOM power, all current concepts for eRHIC would use room temperature beam line absorbers equipped with silicone-carbide dielectrics to absorb HOM power. Concepts, designs and simulations for these beam line absorbers will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB001
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MOPB002	eRHIC Crab Cavity Choice for Ring-ring Design	43
	Q. Wu, I. Ben-Zvi, Y. Hao, S. Verdú-Andrés, B. P. Xiao BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The future electron ion collider eRHIC adopts large crossing angle (22 mrad) to allow fast separation of two beams in the ring-ring scheme. Crab cavities are required to recover the luminosity from geometric losses. Initial calculation shows that the frequency of the cavities for the ion beam is no more than 336MHz. In this paper, we discuss the crab cavity related lattice parameters for both ion and electron beams in ring-ring design, the frequency choice, and the cavity design considerations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB002
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MOPB003	A New High Resolution Optical System for Inspection of Gun-and Multi-cell Resonators in ISO-4 Cleanrooms	47
	M. Schalwat, R. Bandelmann, A. Daniel, N. Krupka, A. Matheisen, S.T. Sieverspresenter DESY, Hamburg, Germany
	Optical inspection of the inner surface of superconducting resonators was established during European XFEL cavity production by usage of the so called OBACHT optical inspection. In addition to the surface inspection by OBACHT a new optical inspection system with integrated high resolution camera is set up at DESY. It allows inspection of multi-cell resonators as well as gun cavity resonators with only single side accessibility to the inner surface. A prototype was commissioned and optical inspections were done with OBACHT and the new system in parallel. Two SRF gun cavities were inspected by this optical system and origin of limitations of the resonators were identified.
	Poster MOPB003 [0.220 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB003
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MOPB004	Design of a RF Quadrupole Resonator for Landau Damping in HL-LHC	51
	K. Papke, A. Grudiev CERN, Geneva, Switzerland
	The design and optimization of a quadrupole resonator for transverse Landau damping in the High Luminosity Large Hadron Collider (HL-LHC) is presented. Two different cavity types are considered whose shape is determined by quadrupolar strength, surface peak fields, and beam coupling impedance. The lower order and higher order mode (LOM and HOM) spectra of the optimized cavities are investigated and different approaches for their damping are proposed. Along an example, the required RF power and optimal external quality factor for the input coupler is derived.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB004
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MOPB005	Beam Dynamics Simulations for the New Superconducting CW Heavy Ion Linca at GSI	56
	M. Schwarz, M. Basten, M. Busch, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia W.A. Barth, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany
	Funding: Work supported by BMBF contr. No. 05P15RFRBA For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI, HIM and IAP is currently in progress. It aims at developing a superconducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the upgraded High Charge Injector (HLI) at GSI. The LINAC design is challenging, due to the requirement of intense beams in CW-mode up to a mass-to-charge ratio of 6 while covering a broad output energy range from 3.5 to 7.3 MeV/u with minimum energy spread. After sucessful tests with the first CH cavity in 2016 demonstrated a promising maximum accelerating gradient of E_a = 9.6 MV/m, recently first beam tests have been started as next milestone at GSI, confirming its flawless functionality. W. Barth et al., Further Layout Investigations for a Superconducting CW-linac for Heavy Ions at GSI, 18th Int. Conf. on RF Superconductivity (SRF17), Lanzhou, China, July 2017, paper MOPB023.*
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB005
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MOPB007	Design of the Superconducting Quarter Wave Resonators for HIAF	59
	C. Zhang, L. Chen, Q.W. Chu, H. Guo, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, L. Li, Y.M. Li, F. Pan, T. Tan, R.X. Wang, A.D. Wu, Q.J. Wu, P.R. Xiong, W.M. Yue, S.H. Zhang, S.X. Zhang IMP/CAS, Lanzhou, People's Republic of China
	A heavy ion accelerator facility (HIAF) is under development in the Institute of Modern Physics. For the low energy superconducting accelerating section, two types of quarter wave resonators with frequency of 81.25 MHz and β of 0.05 and 0.10 have been proposed. The electro-magnetic design has been optimized in order to reach the high accelerating voltage, and the optimization also included the drift tube face tilting to compensate for the beam steering caused by the asymmetry in the quarter wave resonator geometry.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB007
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MOPB008	Input Power Coupler for NICA Injector Coaxial Quater Wave SC Cavity	61
	M.V. Lalayan, T.A. Bakhareva, M. Gusarovapresenter, S.V. Matsievskiy MEPhI, Moscow, Russia
	New coaxial power coupler research and development results are presented and discussed. Coupler is proposed for superconducting QWR cavities being under consideration now as option for planned Nuclotron-based Ion Collider fAcility (NICA) injector upgrade. The goal was to develop power coupler operating at 162 MHz and feeding SC cavity with about 20 kW RF power. It provides Qext tuning range (1.5-3)E5 by inner conductor movement. Conservative design with two identical disk ceramic windows was chosen. Electrodynamic, thermal and mechanical simulations were carried out.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB008
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MOPB009	Progress of 650 MHz SRF Cavity for eRHIC SRF Linac	64
	W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, C. Pai, R. Porqueddu, K.S. Smith, R. Than, J.E. Tuozzolo, F.J. Willeke, A. Zaltsman BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, 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. eRHIC ERL SRF requires 160 5-cell 650 MHz SRF cavities. The 650 MHz cavity has been designed and two prototypes have been fabricated, one Cu cavity for HOM study and one Nb cavity for cavity performance study. This paper will describe cavity design and the progress of prototyping.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB009
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MOPB010	Design of the 2×4-cell Superconducting Cryomodule for the Free-electron Laser	67
	X. Luo, C.L. Lao, M. Li, L.J. Shan, X.M. Shen, H. Wang, X. Yang, K. Zhoupresenter CAEP/IAE, Mianyang, Sichuan, People's Republic of China X.Y. Lu, S.W. Quan, F. Wang PKU, Beijing, People's Republic of China
	A 2×4-cell superconducting linac module for the THz-FEL facility has been developed at the China Academy of Engineering Physics, which is expected to provide 6~8 MeV quasi-CW electron beams with an average current of 1~5 mA. The design of the cryomodule is presented in this paper. The dynamic and static heat load have been evaluated to reasonable level. The temperature distribution inside the cryomodule has been optimized by simulation, as well as mechanical structure and the magnetic shielding.
	Poster MOPB010 [1.019 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB010
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MOPB011	CEA Cryomodules Design for SARAF Phase 2	70
	C. Madec CEA, Gif-sur-Yvette, France N. Bazin, D. Chirpaz-Cerbat, R. Cubizolles CEA/IRFU, Gif-sur-Yvette, France P. Brédy CEA/DSM/IRFU, France R. Bruce, P. Hardy, F. Leseigneur, Th. Plaisant, J. Plouin CEA/DRF/IRFU, Gif-sur-Yvette, France
	CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40.1 MeV. The SCL consists in 4 cryomodules separated by warm diagnostics housing beam diagnostics. The first two identical cryomodules host 6 half-wave resonator (HWR) low beta cavities (β = 0.091), 176 MHz. The last two identical cryomodules are equipped with 7 HWR high-beta cavities (β = 0.181), 176 MHz. The beam is focused through superconducting solenoids located between cavities housing steering coils. A Beam Position Monitor is placed upstream each solenoid. A diagnostic box containing a beam profiler and a vacuum pump will be placed at the end of each cryomodule. The cryomodules and the warm sections are being designed. These studies will be presented in this poster.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB011
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MOPB012	Status of the IFMIF LIPAc SRF Linac	74
	N. Bazin, C. Boulch, A. Bruniquel, P. Carbonnier, J.K. Chambrillon, G. Devanz, F. Éozénou, P. Hardy, H. Jenhani, O. Piquet, J. Plouin, A. Riquelme, D. Roudier, C. Servouin CEA/DRF/IRFU, Gif-sur-Yvette, France P. Charon, S. Chel, G. Disset, L. Maurice, J. Relland, B. Renard CEA/IRFU, Gif-sur-Yvette, France P. Contrepois CEA/DSM/IRFU, France D. Regidor, F. Toral CIEMAT, Madrid, Spain
	The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz and eight focusing solenoids. This paper presents the status of the IFMIF SRF Linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB012
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MOPB013	European XFEL Input Coupler Experiences and Challenges in a Test Field	78
	F. Hoffmann, D. Kostin, W.-D. Möller, D. Reschke, M. Wiencek DESY, Hamburg, Germany
	102 European XFEL accelerating modules with 816 superconducting cavities and main input RF power couplers were assembled and then tested at DESY prior to installation in the European XFEL tunnel. In the Accelerating Module Test Facility (AMTF) warm and cold RF tests were done. The test results went directly to the operational setup for the LINAC. Main input couplers did present several problems during the tests, resulting in some minor coupler design changes as well as in a few repair actions. The experience got from the said testing operation is worth to be shared and is presented here together with a discussion.
	Poster MOPB013 [0.648 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB013
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MOPB015	Accelerator Module Repair for the European XFEL Installation	82
	E. Vogel, S. Barbanotti, F. Hoffmann, K. Jensch, D. Kostin, L. Lilje, W.-D. Möller, M. Schmökel, H. Weise DESY, Hamburg, Germany S. Berry, O. Napoly CEA/DSM/IRFU, France M. Sienkiewicz, J. Świerbleski, M. Wiencek IFJ-PAN, Kraków, Poland
	Repair actions of different extent have been performed at 61 modules of the 100 accelerating series modules for the European XFEL to qualify them for the tunnel installation. Four modules could not be repaired in time. CEA Saclay managed to perform three major repairs in parallel to the series module integration, the residual repair actions took place at DESY Hamburg. In this paper we will give an overview on the various technical problems which required being fixed before the tunnel installation and on the repair actions performed.
	Poster MOPB015 [9.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB015
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MOPB016	Operation of Diamond Superconducting RF Cavities	87
	P. Gu, C. Christou, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink DLS, Oxfordshire, United Kingdom
	The Diamond Light Source storage ring has been in operation using superconducting RF cavities since 2007. Diamond has four superconducting cavity modules with two usually installed at any one time. The four cavities perform differently in many aspects such as reliable operating parameters and time in service, with the longest in continuous service for 7 years without failure and the shortest failing after only 8 months. All Diamond superconducting RF cavities suffered many fast vacuum trips in their early years, but after many years of efforts, the performance of the cavities have now been effectively managed by weekly conditioning, partial warm-up during shut down and cavity voltage level control. We will discuss our experience with superconducting RF cavities and our future plan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB016
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MOPB017	Multiphysics Simulations of the Wide Opened Waveguide Crab-cavity	90
	K. Papke, A. Amorim Carvalho, A. Grudiev, C. Zanoni CERN, Geneva, Switzerland
	In the frame of a FCC study a first prototype of a compact superconducting crab-cavity, using Nb-on-Cu-coating technique is being manufactured and investigated. The design, which is based on the ridged waveguide resonator, is subjected to multipacting and pressure sensitivity simulations. First results of theses simulations are presented and compared to those of other SRF cavities. Furthermore, several aspects related to the design of the fundamental mode coupler and HOM dampers are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB017
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MOPB018	Testing of SRF Cavities and Cryomodules for the European Spallation Source	95
	N. Elias, E. Asensi Conejero, C. Darve, N.F. Hakansson, W. Hees, C.G. Maiano, F. Schlander ESS, Lund, Sweden
	The European Spallation Source (ESS) is currently under construction in Lund, Sweden. The ESS linear accelerator aims to deliver a 62.5 mA , 2.86 ms long proton beam onto a rotating tungsten target, at 14 Hz repetition rate, thus achieving an energy of 2 GeV and 5 MW power. Most of the beam acceleration happens in the superconducting fraction of the linac, which is composed of three sectors of cryomodules named after the cavities housed within. The first sector of the SRF linac is composed of 13 Spoke cryomodules containing 2 double-spoke cavities with a geometric beta of 0.5, the second is composed of 9 medium beta cryomodules each housing four elliptical cavities (β=0.67) and finally 21 high beta cryomodules enclosing four elliptical cavities (β=0.86). ESS has strategically built up a SRF collaboration with other European institutions, these partners will deliver through In-Kind agreements cavities and cryomodules performing within the ESS specification. This article describes the process leading to the acceptance of cavities and cryomodules received from the different partners and the necessary testing required prior to the final installation in the ESS tunnel.
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MOPB019	Interface Challenges for the SRF Cryomodules for the European Spallation Source	100
	F. Schlander, C. Darve, N. Elias, C.G. Maiano ESS, Lund, Sweden P. Bosland CEA/DSM/IRFU, France G. Olry IPN, Orsay, France
	The European Spallation Source is currently under construction in Lund in southern Sweden. The main part of the accelerator will consist of two different types of cryomodules housing three different types of cavities ' double spoke cavities and two different elliptical cavities. The spoke cavities as well as the cryomodules will be provided by IPN Orsay, thus the external interfaces to the other accelerator systems have to be verified. While the procurement and assembly of the elliptical cryomodules will be performed by CEA Saclay, the cavities will be provided by INFN Milano and STFC Daresbury. Thus in addition to the external cryomodule interfaces, also the internal interfaces between cavities and cryomodules have to be taken care of. This contribution presents the challenges related to this work.
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MOPB020	An Optimal Procedure for Coupler Conditioning for ESS Superconducting Linac	103
	H. Li Uppsala University, Uppsala, Sweden E. Asensi Conejero, C.G. Maiano, R. Zengpresenter ESS, Lund, Sweden
	An optimal procedure for coupler and cavity conditioning is proposed for the ESS superconducting cavities, which is applicable for different test stands and following installation in the ESS tunnel. A preliminary procedure has been developed and successfully tested at FREIA facility, Uppsala. The preliminary procedure will now be improved by integrating it into LLRF and EPICS control. This will be a joint effort between FREIA and ESS and will be used at the test stands in Lund and on the couplers installed in the tunnel. Developing the conditioning procedures on a common platform offers ESS significant advantages by allowing the procedures to be reused at different sites and by recording data in a consistent format. The details of the procedure, its development and testing will be reported and the future activities will be described.
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MOPB023	Further Layout Investigations for a Superconducting CW-linac for Heavy Ions at GSI	108
	W.A. Barth, K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia M. Basten, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	Very compact accelerating-focusing structures, as well as short focusing periods, high accelerating gradients and very short drift spaces are strongly required for superconducting (sc) accelerator sections operating at low and medium beam energies. To keep the GSI-Super Heavy Element program competitive on a high level and even beyond, a standalone sc continuous wave Linac in combination with the GSI High Charge State injector, upgraded for cw-operation, is envisaged. The first LINAC section (financed by HIM and GSI) as a demonstration of the capability of 216 MHz multi gap Crossbar H-structures (CH) is still in the beam commissioning phase, while an accelerating gradient of 9.6 MV/m (4 K) at a sufficient quality factor has been already reached. Recently the overall Linac design, based on a standard cryomodule, comprising three CH cavities, a rebuncher section and two 9.3 T-solenoidal lenses, has to be fixed. This paper presents the status of the Linac layout studies as well as the integration in the GSI accelerator facility.
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MOPB024	Steps Towards Superconducting CW-linac for Heavy Ions at GSI	112
	M. Miski-Oglu, M. Amberg, K. Aulenbacher, W.A. Barth HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, V. Gettmann, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	A superconducting (sc) cw-Linac at GSI should ensure competitive production of Super Heavies in the future. Further R&D for this cw-Linac, a so called 'Advanced CW-Demonstrator', with maximal energy of 3.5 MeV/u is ongoing. As a first step, the demonstrator project with one sc CH-cavity is near its completion, the beam tests are scheduled for mid-summer 2017. The completion of the 'Advanced CW-Demonstrator' includes successive construction of two new cryogenic modules comprising four CH-cavities and two solenoids each. In this contribution the layout of the cryomodules and the Helium distribution system are presented.
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MOPB028	HOM Coupler Design for CEPC Cavities	115
	H.J. Zheng, F. Meng, J.Y. Zhai IHEP, Beijing, People's Republic of China
	Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400) In this paper，it will be presented the higher order mode (HOM) coupler design for the Circular Electron-Positron Collider (CEPC) 650 MHz 2-cell cavity. The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. A double notch coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe. This paper summarizes the RF design of the HOM coupler, tolerance analysis, thermal analysis as well as mechanical structures.
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MOPB031	Fabrication and Cold Test Result of FRIB β=0.53 Pre-production Cryomodule	120
	H. Ao, J. Asciutto, B. Bird, N.K. Bultman, E.E. Burkhardt, F. Casagrande, C. Compton, K.D. Davidson, K. Elliott, A. Ganshyn, I. Grender, W. Hartung, L. Hodges, I.M. Malloch, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarskipresenter, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, S. Stark, J.D. Wenstrom, M. Xu, T. Xu, Z. Zheng FRIB, East Lansing, USA A. Facco INFN/LNL, Legnaro (PD), Italy
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The driver linac for the Facility for Rare Isotope Beams (FRIB) comprises four kinds of cavities (β=0.041, 0.085, 0.29, and 0.53) and six types of cryomodules including matching modules. FRIB has completed the fabrication and the cold test of a β=0.53 pre-production cryomodule, which is the first prototype for a half-wave (β=0.29 and 0.53) cavity. This paper describes the fabrication and the cold test result of the β=0.53 pre-production cryomodule including lessons learned.
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MOPB034	Selection of the Type of Accelerating Structures for the Second Group of Cavity SC Linac Nuclotron-NICA	125
	M. Gusarova, A.A. Gorchakov, M.V. Lalayan, D.V. Surkov, K.V. Taletskiy MEPhI, Moscow, Russia A.V. Butenko JINR/VBLHEP, Dubna, Moscow region, Russia D.A. Shparla Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus A.O. Sidorin, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia
	The paper summorises the research results aimed on the choice of superconducting accelerating cavities for the second section of the SC linac Nuclotron-NICA injector project. This choice was based on comparative analysis of accelerating structures electrodynamic characteristics taking into account technological challenges of bulk niobium cavities production.
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MOPB035	Cryogenic Probe Station at Old Dominion University Center for Accelerator Science	128
	J. Makita, J.R. Delayen, A.V. Gurevich ODU, Norfolk, Virginia, USA G. Ciovati JLab, Newport News, Virginia, USA
	With a growing effort in research and development of an alternative material to bulk Nb for a superconducting radiofrequency (SRF) cavity, it is important to have a cost effective method to benchmark new materials of choice. At Old Dominion University's Center for Accelerator Science, a cryogenic probe station (CPS) will be used to measure the response of superconductor samples under RF fields. The setup consists of a closed-cycle refrigerator for cooling a sample wafer to a cryogenic temperature, a superconducting magnet providing a field parallel to the sample, and DC probes in addition to RF probes. The RF probes will extract a quality factor from a sample patterned in a coplanar waveguide resonator structure on a 2' wafer. From the measured quality factor, the surface resistance and the penetration depth as a function of temperature and magnetic field will be calculated. This paper will discuss the design and measurement procedures of the current CPS setup.
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MOPB036	The Study of Deposition Method of Nb3Sn Film on Cu Substrate	131
	L. Xiao, X.Y. Lu, W.W. Tan, D. Xie, D.Y. Yang, Y. Yang, Z.Q. Yang, J. Zhao PKU, Beijing, People's Republic of China
	Our work is mainly focused on the fabrication methods of Nb3Sn films on Cu substrates and film's properties. There are diffraction peaks of Nb3Sn in the X-ray diffraction patterns in which without diffraction peaks of copper compounds. Scanning electron microstructures of Nb3Sn film reflect its nice compactness and binding force between film and substrate.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB036
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MOPB037	Progress of the 2x4-Cell Superconducting Accelerator for the CAEP THz-FEL Facility	134
	K. Zhou, C.L. Lao, M. Li, X. Luo, L.J. Shan, X. Shen, H. Wang, X. Yang CAEP/IAE, Mianyang, Sichuan, People's Republic of China X.Y. Lu PKU, Beijing, People's Republic of China
	The high average power THz radiation facility is now under construction in China Academy of Engineering Physics. The superconducting accelerator is one of the most important components for this facility, including two 4-Cell TESLA superconducting radio frequency cavities. The designed effective field gradients for both cavities are 10^-12 MV/m. This paper will present the progress of the 2x4-cell superconducting accelerator, mainly including its construction and cryogenic test in Chengdu. At 2 K state, the cryomodule works smoothly and stably. The effective field gradients of both cavities have achieved 10 MV/m. Further beam loading experiments are now in progress.
	Poster MOPB037 [5.124 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB037
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MOPB040	ESS High-beta Cavity Test Preparations at Daresbury Laboratory	137
	P.A. Smith, L. Bizel-Bizellot, K.D. Dumbell, M. Ellis, P. Goudket, A.J. Moss, E.F. Palade, S.M. Pattalwar, M.D. Pendleton, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Science and Technology Facility Council is responsible for supplying, and testing 84 High beta elliptical SRF cavities, as part of the UK In Kind Contribution to the European Spallation Source (ESS). The High-β=0.86, cavities have been designed by CEA- Saclay and are a five cell Niobium cavity operating at 704.42 MHz. They are required to provide an accelerating gradient of 19.9 MV/m at an unloaded Q of 5x10⁹. Preparations are underway to upgrade the cryogenic and RF facilities at Daresbury laboratory prior to the arrival of the first cavities. As part of these arrangements, a niobium coaxial resonator has been manufactured, to validate the test facility. The design considerations, for the coaxial resonator are presented, along with preliminary results. The RF measurement system to perform the cavity conditioning and testing is also presented.
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MOPB041	Status of the SOLEIL Superconducting RF System	141
	M. Diop, J.P. Baete, R.C. Cuoq, H.D. Dias, J.L. Labelle, L.R. Lopes, M. Louvet, P. Marchand, C.M. Monnot, S. Petit, F. Ribeiro, T. Ruan, R. Sreedharan, K.T. Tavakoli SOLEIL, Gif-sur-Yvette, France
	The 352 MHz SOLEIL SRF systems consist in two cryomodules, each containing a pair of SC Nb/Cu cavities, cooled with LHe at 4K from a single 350 W cryogenic plant. In order to store 500 mA, a power of 575 kW and an accelerating voltage of 3-4 MV are required. The RF power is provided by 4 SSPA's delivering up to 180 kW each. The original cavity input power couplers, which are LEP-type antennas designed to handle up to 200 kW, are being replaced by upgraded versions, able to operate at 300 kW CW. This will open the possibility to operate at full beam current with only one active cryomodule. The SRF system operational experience over the past ten years as well as the different upgrades will be reported here.
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MOPB042	The TRIUMF/VECC Injector Cryomodule Performance	144
	Y. Ma, K. Fong, T. Junginger, D. Kishi, A.N. Koveshnikov, R.E. Laxdalpresenter, N. Muller, R.R. Nagimov, D.W. Storey, E. Thoeng, Z.Y. Yao, V. Zvyagintsev TRIUMF, Vancouver, Canada U. Bhunia, A. Chakrabarti, S. Dechoudhury, V. Naik VECC, Kolkata, India
	The collaboration on superconducting electron Linac for rare ion beam facilities ARIEL (Advanced Rare Iso-topE Laboratory) [1-4] and ANURIB [5] (Advanced Na-tional facility for Unstable and Rare Isotope Beams) has resulted in production of a superconducting Injector Cryomodule (VECC ICM) at TRIUMF for VECC. The cryomodule design utilizes a unique box cryomodule with a top-loading cold mass. The hermetic unit consists of a niobium cavity which operating at 1.3GHz and connected with two symmetrically opposed couplers which can deliver 100kW RF power to the beam. Liquid helium supplied at 4.4 K is converted to superfluid helium-II through a cryogenic insert on board which includes 4 K phase separator, 4K/2K heat exchanger and Joule-Thompson valve. In 2016, the VECC ICM has been tested at TRIUMF and demonstrated 10.5 MeV acceleration. A summary of the VECC ICM commissioning are presented.
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MOPB043	Pansophy, a JLab SRF Engineering Data Management System, Supporting Data Collection, Retrieval and Analysis Utilized by LCLS-II	148
	V.D. Bookwalter, M. Dickey, E.A. McEwen, M.G. Salvador JLab, Newport News, Virginia, USA
	Pansophy is an Engineering Data Management System that provides a comprehensive solution for managing information in the production and testing of cryomodules. It is especially suited to supporting the Data & Quality Management Systems for large projects like LCLS-II. With extensive amounts of data collected for an individual project, data retrieval to facilitate feedback and enhancement of production and processing activities is a high priority. The priority shares importance with the needs of managing the project, including production status, NCR, and Quality Management reports. Recent Pansophy enhancements have been to Data and Quality management reports and statistical analysis. Such enhancements include a database driven menu system, extended MSWord macro and preprocessing of travelers, and an extensive reporting system. The reporting system allows managers and group leaders to quickly respond to the needs of the project in areas of cavity and cryomodule production, data collection, NCR, Quality Management and schedule. Extensions include integration with the SRF inventory system PRIMeS, allowing traceability from receiving of manufactured parts to final cryomodule product.
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MOPB044	Magnetic Hygiene Control on LCLS-II Cryomodules Fabricated at JLab	153
	G. Cheng, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, R.A. Legg, H. Park, K.M. Wilson, L. Zhao JLab, Newport News, Virginia, USA
	Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and the LCLS-II project. Jefferson Lab (JLab) is in collaboration with Fermi Na-tional Accelerator Laboratory (Fermilab) to build 18 cryomodules to install at the SLAC National Accelerator Laboratory's tunnel as part of the Linac Coherent Light Source upgrade project (LCLS-II). Each LCLS-II cry-omodule hosts 8 superconducting niobium cavities that adopt the nitrogen doping technique, which aims to en-hance the cavity quality factor Qo to reduce the consumption of liquid helium used to cool down the cavities. It is known that the Qo of niobium cavities is affected by cavity surface magnetic field. Traditionally, magnetic shields made of high magnetic permeability mu-metals are employed as a passive shielding of the ambient magnetic fluxes. During the LCLS-II cryomodule development, magnetic hygiene control that includes magnetic shielding and demagnetization of parts and the whole-machine is implemented. JLab and Fermilab worked closely on developing magnetic hygiene control procedures, identifying relevant tools, investigating causes of magnetization, magnetic field monitoring, etc. This paper focuses on JLab's experiences with LCLS-II cryomodule magnetic hygiene control during its fabrication. Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.
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MOPB045	JLab New Injector Cryomodule Design, Fabrication and Testing	158
	G. Cheng, M.A. Drury, J.F. Fischer, R. Kazimi, K. Macha, H. Wang JLab, Newport News, Virginia, USA
	Funding: U.S. DOE Contract No. DE-AC05-06OR23177. A new Injector Cryomodule (INJ CM) aimed to replace the existing Quarter Cryomodule in the CEBAF tunnel has been developed at Jefferson Lab (JLab). It is sched-uled to be first tested in the Cryomodule Test Facility (CMTF) for module performance then the Upgraded Injector Test Facility (UITF) with electron beam. This new cryomodule, hosting a 2-cell and 7-cell cavity, is designed to boost the electron energy from 200 keV to 5 MeV and permit 380 uA - 1.0 mA of beam current. The 2-cell cavity is a new design whereas the 7-cell cavity is refurbished from a low loss cavity from the retired JLab Renascence Cryomodule. The INJ CM adopts quite a few designs from the JLab 12 GeV Upgrade Cryomodule (C100). Examples of this include having the cold mass hung from a spaceframe structure by use of axial and transverse Nitronic rods, cavities to be tuned by scissor-jack style tuners and the end cans are actually modified from C100 style end cans. However, this new INJ CM is not a quarter of the C100 Cryomodule. This paper focuses on the major design features, fabrication and alignment process and testing of the module and its components. Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.
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MOPB046	LCLS-II Cryomodule Production at JLab	163
	R.A. Legg, G. Cheng, E. Daly, G.K. Davis, M.A. Drury, J.F. Fischer, T. Hiatt, N.A. Huque, L.K. King, J.P. Preble, A.V. Reilly, M. Stirbet, K.M. Wilson JLab, Newport News, Virginia, USA
	Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515. The LCLS-II cryomodule construction program leverages the mature XFEL cryomodule design to produce technologically sophisticated cryomodules with a minimum of R&D according to an accelerated manufacturing schedule. Jlab, as one of the partner labs, is producing 18 cryomodules for LCLS-II. To meet the quality and schedule demands of LCLS-II, many upgrades to the JLAB cryomodule assembly infrastructure and techniques have been made. JLab has installed a new cleanroom for string assembly and instituted new protocols to minimize particulate transfer into the cavities during the cryomodule construction process. JLab has also instituted a set of magnetic hygiene protocols to be used during the assembly process to minimize magnetic field impingement on the finished cavity structure. The goal has been to have gradients, both maximum and field emission onset, that do not degrade between the cavity vertical test and final cryomodule qualification, while maximizing the Q0 of each finished cavity. Results from the prototype cryomodule assembly are presented.
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MOPB049	Upgraded Cavities for the CEBAF Cryomodule Rework Program	168
	R.A. Rimmer, G. Cheng, G. Ciovati, W.A. Clemens, E. Daly, G.K. Davis, J. Follkie, D. Forehand, F. Fors, J. Guo, J. Henry, K. Macha, F. Marhauser, G.R. Myneni, L. Turlington JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The CEBAF cryomodule rework program has been a successful tool to recover and maintain the energy reach of the original baseline 6 GeV accelerator. The weakest original modules with eight five-cell cavities assembled in four 'pairs', with a specification when new of 20 MV per cryomodule (5 MV/m), are disassembled, re-cleaned with modern techniques and re-qualified to at least 50 MV (12.5 MV/m), (leading to the acronym 'C50'). The cost per recovered MV is much less than building new modules. However over time the stock of weak modules is being used up and the voltage gain per rework cycle is diminishing. In an attempt to increase the gain per cycle it is proposed to rework the cavities by replacing the original accelerating cells with new ones of an improved shape and better material. The original CEBAF HOM and FPC end groups are retained. The goal is to achieve up to 75 MV (18.75 MV/m) for the reworked module ('C75'). We report on the fabrication experience and test results of the first trial pair, containing two such reworked cavities.
	Poster MOPB049 [1.503 MB]
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MOPB050	Cavity Processing and Testing Activities at Jefferson Lab for LCLS-II Production	173
	L. Zhao, G.K. Davis, J. Follkie, D. Forehand, K. Macha, A.D. Palczewski, A.V. Reilly JLab, Newport News, Virginia, USA
	Funding: Work supported by Jefferson Science Associates, LLC under U.S. DOE Contracts DE-AC05-06OR23177 and DE-AC02-76SF00515 for the LCLS-II Project. Cryomodule production for LCLS-II is well underway at Jefferson Lab. This paper explains the process flow for production cavities, from being received at the Test Lab to being assembled onto cavity strings. Taking our facility and infrastructure into consideration, process optimization and process control are implemented to ensure high quality products.
	Poster MOPB050 [2.338 MB]
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MOPB052	Dual-ridge Waveguide Load Design for eRHIC	177
	P. Kolb, Y. Gao, C. Pai, R. Porqueddu, K.S. Smith, W. Xu BNL, Upton, Long Island, New York, USA Y. Gao PKU, Beijing, People's Republic of China
	Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. To increase the real estate gradient in the eRHIC electron accelerator waveguide HOM couplers are being considered. These significantly reduce the length of individual cavities and address inter-cavity trapped modes, allowing for an increased number of cavities per cryomodule, which would increase the real estate gradient. The choice of waveguide went to a dual ridge waveguide due to a smaller size compared to rectangular waveguides. The waveguide termination, to convert the RF energy into thermal energy, is a custom designed load based on a silicon carbide dielectric that is already being used in beamline absorbers. Simulations of the RF properties of the load are presented as well as first measurements on a prototype.
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MOPB053	RF Energy Harvesting of HOM Power	180
	C. Xu, I. Ben-Zvi, Q. Wupresenter, T. Xin BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA
	In an accelerator cavity, Higher Order Modes (HOM) are generated by the current of the beam. The HOM power can reach tens of kilowatts in a high current accelerator, depending on the details of the beam and cavity design. In this report, we propose a novel RF harvesting system to recover the HOM power into DC power which can further used for various purposes such as driving a solid state or klystron RF amplifier to supply fundamental RF power at other frequencies, charge batteries etc. The efficiency would be a product of the energy recovery and regeneration efficiencies, where the state of art is 90%. The proposed HOM power recycling system contains a multiple band harmonic RF coupler, broadband RF antenna system, a high power rectifier diode circuit and a DC load. 1) Collider-Accelerator Department, Brookhaven National Lab, Upton, NY 11973, USA 2) Physics & Astronomy Department, Stony Brook University, Stony Brook, NY 11794, USA
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MOPB054	Design of Fundamental Power Coupler for High Intensity Heavy-ion Accelerator	183
	B. Bing, T.M. Huang, Q. Ma, F. Meng, W.M. Pan IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	A single-window coaxial coupler at warm has been designed for high intensity heavy-ion accelerator. The coupler is designed to handle 100 kW CW power of 325 MHz and is currently being fabricated. T-bend transition and doorknob have been taken into account. The length of the T-bend short circuit is sensitive to S parameters and contributes to the online adjustment of VSWR in RF conditioning. The doorknob type is adopted to realize the transition from a half-height WR 2300 waveguide to a coaxial line ended with a coupling antenna. This paper describes the RF design, thermal stress and heat load analysis of the coupler as well as multipacting simula-tions.
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MOPB061	Quality Control of Copper Plating in STF-2 Input Power Couplers	186
	E. Kako, R. Ueki KEK, Ibaraki, Japan K. Hiroaki, J. Taguchi Nomura Plating Co, Ltd., Osaka, Japan K. Okihira, K. Sennyu MHI, Hiroshima, Japan F. Saito, H. Umezawa Tokyo Denkai Co., Ltd., Tokyo, Japan O. Yushiro Toshiba Electron Tubes & Devices Co., Ltd, Tokyo, Japan
	Purity of thin copper plating using in input power couplers for superconducting cavities is one of important characteristics for considering thermal losses at low temperature. Various samples of thin copper plating on stainless sheets was fabricated by three companies with their own plating techniques. The RRR values of the samples with different thickness of copper plating were compared in the condition before and after heat treatment at 800oC in a brazing furnace. Deterioration of the RRR was observed in all of samples after heat treatment. The results of the RRR measurements and sample analysis of impurities will be reported in this paper.
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MOPB062	Development of HOM Absorbers for CW Superconducting Cavities in Energy Recovery Linac	191
	T. Ota, A. Miyamoto, K. Sato, M. Takasaki, M. Yamada Toshiba, Yokohama, Japan E. Kakopresenter, T. Konomi, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	Higher Order Modes (HOM) absorbers for superconducting cavities have been developing at TOSHIBA in collaboration with High Energy Accelerator Research Organization (KEK) since 2015. Prototype HOM absorbers for 1.3 GHz 9-cell superconducting cavity were fabricated. An AlN lossy dielectrics cylinder was brazed with a copper cylinder, and the cool-down tests by nitrogen gas was carried out. Copper cylinders and SUS flanges were joined by electron beam welding to fabricate a whole prototype HOM absorber. Fabrication process of the prototype HOM absorber will be presented in this paper.
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MOPB063	Fundamental Studies for the STF-type Power Coupler for ILC	194
	Y. Yamamoto, E. Kako, T. Matsumoto, S. Michizono, A. Yamamoto KEK, Ibaraki, Japan M. Irikura, M. Ishibashi, H. Yasutake Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi, Japan
	From the view point of mass-production for the power coupler in ILC, the fundamental studies for the STF-type power coupler are under progress by the collaboration between KEK and TETD. At present, there are various rinsing procedures for power coupler in the world-wide laboratories. In this R&D, the main topic is to investigate the various rinsing effects in the copper plating and the ceramic through the high power test. In this paper, the first results will be presented.
	Poster MOPB063 [2.237 MB]
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MOPB064	High Power Test for Plug-compatible STF-type Power Coupler for ILC	199
	Y. Yamamoto, E. Kako, T. Matsumoto, S. Michizono, A. Yamamoto KEK, Ibaraki, Japan C. Julie, E. Montesinos CERN, Geneva, Switzerland
	From the view point of plug-compatibility for the power coupler in the ILC, recommended by Linear Collider Collaboration in 2013, new STF-type power couplers with 40mm of input port diameter were re-designed, fabricated and successfully high-power-tested. Moreover, from the view point of the cost reduction for the ILC, another type of power couplers with TiN coating-free ceramic were also fabricated and high-power-tested by the collaboration between CERN and KEK. In this paper, the detailed results for the both power couplers will be presented.
	Poster MOPB064 [6.671 MB]
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MOPB065	Development of Hybrid Superconducting Photocathodes on Niobium Using High QE Coatings	205
	M. Warren, A.R. Denchfield, N. Samuelson, J. Zasadzinski IIT, Chicago, Illinois, USA W. Gai, J.H. Shao, E.E. Wisniewski ANL, Argonne, Illinois, USA L.K. Spentzouris, Z.M. Yusof Illinois Institute of Technology, Chicago, Illinois, USA
	High power, low emittance electron beams require superconducting RF photoinjectors, typically made of pure Nb, and a superconducting photocathode is desired. However, superconductivity and high photocathode quantum efficiency (QE) are not compatible, e.g. QE for pure Nb is only 10^-5 at 260 nm wavelength. Here is presented the current status of the development of hybrid superconducting photocathodes by the deposition of thin films of a high QE metal or semiconductor on Nb. Nb plugs coated with 10-100 nm of Mg have been tested for adhesion and dark current under RF fields as high as 60MV/m. QE measurements show significant enhancements over Nb. In another test, ultra thin films of the high QE material Cs2Te deposited on Nb are reported. Using the standard deposition procedure, QE ~12% is found for films ~ 200Å. As the thickness is reduced QE maintains a high value ~ 6% for films as thin as 2.0 nm. These results are quite promising for future superconducting photocathodes.
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MOPB066	Development of 81.25 MHz 20 kW SSPA for RAON Accelerator	210
	C.O. Choi, H. Jang, H.C. Jung, D.Y. Lee, K.T. Son IBS, Daejeon, Republic of Korea
	A heavy ion accelerator, RAON is under development in Daejeon, Korea by Rare Isotope Science Project (RISP). In this accelerator, 81.25 MHz Radio Frequency Quadrupole (RFQ) will be used for the acceleration of various ions from several tens of keV/u to about half MeV/u. For this system two 80 kW RF power sources are planned and RISP will develop them with a solid state power amplifier (SSPA) architecture. As a first step, a 20 kW SSPA was developed and its performance was tested. In this presentation the current status of developed SSPA and its test results will be presented
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MOPB068	Development of 4-way 81.25 MHz 20 kW High Power Combiner Using Parallel Plate Structure	213
	K.T. Son, C.O. Choi, H. Jang, H.C. Jung, D.Y. Lee IBS, Daejeon, Republic of Korea
	The recent development of semiconductor technology has proved that solid-state RF amplifier is a quite effective alternative high power RF source for numerous accelerator applications. To develop a high power SSPA system, high power combiner is required to combine the RF power from a lot of solid-state RF module. The parallel plate RF power combiner, which is designed to combine various high power modules, is developed for RAON(Rare the rare isotope accelerator complex for on-line experiment). In this presentation, the status of developed 81.25 MHz 20 kW power combiner will be described.
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MOPB069	Design of the High Power Input Coupler for CEPC Main Ring Cavity *	216
	T.M. Huang, Q. Ma, J.Y. Zhai IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The main ring cavities of CEPC project are two-cell el-liptical superconducting cavities operating at 650 MHz in CW mode. Each cavity equips with one high power input coupler and each coupler has to deliver at least 300 kW of CW RF power to the beam. A variable coupling from 10⁵ to 2·10⁶ is required to meet different operation modes. Considering the cavities working with high quali-ty factor up to 2·10¹⁰, the coupler assembled with cavity in class 10 clean room is strongly recommended to protect the cavity from contamination. Also, low cryogenic heat loss is one of the important issues for a large scale CW operation machine. Some of the above requirements should be compromise. Therefore, it's a big challenge to design a high power input coupler fulfilling the above requirements simultaneously. A new coupler that employs 75 Ω coaxial line sections, a planar ceramic disk win-dow, a coaxial to waveguide transition and a coupling adjusting actuator has been designed. In this paper, the RF design, thermal stress analysis and preliminary me-chanical design of the coupler are presented.
	Poster MOPB069 [0.735 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB069
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MOPB070	The Improvement of the Power Coupler for CADS SC Spoke Cavities	220
	T.M. Huang, B. Bing, X. Chen, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, G.W. Wang IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	Twenty superconducting spoke cavities mounted in three cryomodules (CM1, CM2 and CM4) were in-stalled in the CADS, a test facility of 10 mA, 25 MeV CW proton linac. Each cavity was equipped with one coaxial type fundamental power coupler (FPC). Fatal window crack was observed during the test cryomod-ule (TCM) commissioning. A series of experiments were subsequently implemented and eventually at-tributed the window crack to the electron bombard-ment from cavity field emission (FE). Improvements covering the coupler cleaning and assembly proce-dure, the structure and position modifications were thus implemented, aiming to reduce the cavity contam-ination and avoid the window damaged by cavity FE electrons. This paper will describe how the coupler window damaged by cavity field emission and the improve-ments for cure. In addition, the performances of FPCs for CM1, CM2 and CM4 were compared.
	Poster MOPB070 [0.613 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB070
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MOPB071	The Recent Research of HOM Damper for Superconducting Cavity in IHEP	223
	F. Meng, T.M. Huang, H.Y. Lin, Q. Ma, W.M. Pan, J.Y. Zhai, P. Zhang, H.J. Zheng IHEP, Beijing, People's Republic of China
	Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400) For high current accelerator, the efficient higher-order mode (HOM) damping is always an important issue. HOM damper with microwave absorbing material is a key component for high power and broadband HOM damping application. To pursue the high damping efficiency, some ideal material with good microwave absorbing capacity is essential during the RF design and fabrication phase. Sometimes the selection and test of material is the first step and also a long step. This paper will present the recent work on HOM dampers for BEPCII 500MHz cavity and CEPC 650MHz cavity in IHEP.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB071
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MOPB072	The Development of the LLRF Control System for the New High Power Test Stand of Couplers	227
	L. Chen, W. Chang, T.C. Jiang, C.L. Li, Y.M. Li, R.X. Wang, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	RF power conditioning is an effective way to suppress multipacting in fundamental mode power couplers. Room temperature test-stand conditioning is an essential step that can be hardly circumvented before couplers are installed on SC cavities. Based on our original one, a new test-stand has been designed and being assembled at IMP. It can work as a multi-task platform conditioning different couplers, including couplers for HWR010 cavities and HWR015 cavities. It is also featured with the capacity to flexibly change β according to different specifications. A variety of conditioning modes have been incorporated into the LLRF system, including frequency sweeping mode, amplitude sweeping mode, arbitrary-duty-cycle mode and triangle-wave mode. In addition, smartly-conditioning has been achieved because of the accomplishment of smart interlocks and automatic reset in the system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB072
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MOPB074	Analysis of Higher Order Modes of the Superconducting Cavities for the China-ADS Injector-II in IMP	231
	C. Zhang, L. Chen, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, Y.M. Li, F. Pan, R.X. Wang, A.D. Wu, Q.J. Wu, W.M. Yue, S.H. Zhang, S.X. Zhang IMP/CAS, Lanzhou, People's Republic of China
	Funding: funded by Natural Science Foundation of China， No.11505253 The influence of the higher order modes on the beam dynamics and the cryogenic losses has been studied for the superconducting section of the CIADS project in this paper. In addition, the necessity of HOM dampers in the Superconducting (SC) cavities is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB074
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MOPB075	Quench Protection in Digital Power Supplies for Superconducting Magnets in ADS	233
	J. Zhao, S. Zhang, Z.Z. Zhou IMP/CAS, Lanzhou, People's Republic of China
	The front-end demo superconducting Linac for Chinese ADS (Accelerator Driven Sub-critical System) project is under construction at institute of modern physics(IMP) in Lanzhou. It will demonstrate the key technologies and the feasibility of a high power beam for the future national project " the Chinese Initiative Accelerator Driven Subcritical System(CIADS)". In this system, there are about 60 superconducting magnets, including solenoids, vertical correction and horizontal correction. They are utilized to focus and correct the proton beam. Quench protection of the superconducting magnets is key to reliability of the facility. A full digital power supply is developed and employed as excitation source for all of these superconducting magnets. In this paper, an FPGA-based quench protection plan implemented in the power supplies is mainly described. The commissioning results show that it is feasible.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB075
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MOPB076	Analysis of the Production, Installation and Commissioning of the European-XFEL Frequency Tuners	235
	R. Paparella, A. Bosotti, D. Sertorepresenter INFN/LASA, Segrate (MI), Italy C. Albrecht, S. Barbanotti, A. Bellandi, J. Branlard, K. Jensch, L. Lilje DESY, Hamburg, Germany C. Cloué, T. Trublet CEA/IRFU, Gif-sur-Yvette, France C. Madec CEA, Gif-sur-Yvette, France
	In the European-XFEL superconducting linac, mechanical frequency tuners equipped with stepper motors and piezoelectric actuators provide cold tuning of each of the 768 1.3 GHz cavities. More than 820 complete tuning systems were fabricated and pre-assembled in industry, tested at several stages before and after assembly and successfully commissioned during cryo-module cold tests at AMTF (DESY). Quality control strategy adopted to preserve the well-assessed tuner reliability through such a large-scale industrial production is critically reviewed and the lessons learned are presented in this paper. The statistical analysis of the large set of data acquired up to the recent commissioning of the entire linac is then summarized.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB076
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MOPB077	Operational Experience of the European-XFEL 3.9 GHz Coaxial Tuners	240
	R. Paparella, A. Bellandi, A. Bignami, A. Bosotti, D. Sertore INFN/LASA, Segrate (MI), Italy C.G. Maiano ESS, Lund, Sweden P. Pierinipresenter DESY, Hamburg, Germany
	The European-XFEL injector hosts a third-harmonic section composed by a module with eigth 3.9 GHz cavities equipped with a coaxial frequency tuner inspired by INFN-LASA Blade Tuner design. The 3.9 GHz tuning system met specifications during all the injector runs in 2016 up to the recent commissioning of the entire linac; it matched the required tuning range and frequency sensitivity although higher than expected cavity detuning was experienced during pressure transients in the cryogenic system. An analysis of all collected experimental data is reported in this paper together with the strategy developed to provide a sound and effective retuning routine to the control room operator.
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MOPB078	Power Coupler Design for the LUCRECE Project	245
	H. Guler, D. Auguste, J. Bonis, O. Bouras, M. El Khaldi, W. Kaabi LAL, Orsay, France
	The LUCRECE project aims at developing an elementary RF system (cavity, power source, LLRF and controls) suitable for continuous (CW) operation at 1.3 GHz. This effort is made in the framework of the advanced and compact FEL project LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation), using superconducting linac technology for high repetition rate and multi-user operation (http://www.lunex5.com). In this context, based on its large experience on coupler design and RF conditioning, LAL Laboratory is in charge of the design and the fabrication of RF couplers that could operate at up to 15-20 kW in CW mode. For this purpose, couplers based on CORNELL 65kW CW couplers (RF power couplers for the Cornell ERL injector) are under consideration and will be adapted to the LUCRECE needs. Electromagnetic simulations and associated thermal heating will be discussed. Methods to decrease the thermal impact will be considered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB078
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MOPB079	HOM Coupler Alterations for the LHC DQW Crab Cavity	249
	J.A. Mitchell Lancaster University, Lancaster, United Kingdom G. Burt, N.C. Shipman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Calaga CERN, Geneva, Switzerland S. Verdú-Andrés, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA
	As part of the High Luminosity Large Hadron Collider (HL-LHC) project, 16 crab cavities are to be installed in the LHC in 2025. The two crab cavity designs are the Double Quarter Wave (DQW) and Radio Frequency Dipole (RFD). Preliminary beam tests in the Super Proton Synchrotron (SPS) are planned for both cavity types, with the DQW scheduled for testing in 2018. In reference to to Higher Order Mode (HOM) damping, the DQW has three identical on-cell HOM couplers. These HOM couplers provide a band-stop response at the frequency of the fundamental mode and act as a transmission path for the cavity HOMs. For the SPS cavity design, several geometric constraints exist. These give rise to dimensional limitations which in-turn impose limitations on the RF performance of the HOM couplers. As such, for the LHC assembly, the HOM coupler design is re-visited to take into account the relaxed geometric limitations, hence allowing the feasibility of an increased RF performance to be investigated. In addition to the RF performance, several geometric alterations were incorporated to ease manufacturing processes, tolerances and costs.
	Poster MOPB079 [2.038 MB]
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MOPB080	The Stable Operation of MPG and Measurement of Output	254
	B.T. Li, X.Y. Lu, L. Xiao, D.Y. Yang, Y. Yang, Z.Q. Yang, J. Zhao PKU, Beijing, People's Republic of China
	The concept of micro-pulse electron gun(MPG) was proposed decades ago. It can provide electron beam with high current, short pulse and low emittance. But it is still not put into practical use as electron source because of its unsteady operating state. This paper presents an experimental result of the steady running of MPG which can operate stably for more than ten hours. The energy spread of the electron beam is also measured, the peak is located at near 20eV and half width is less than 15eV .
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB080
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MOPB082	A Preliminary Scheme for X-ray Emission Based on Micro-pulse Electron Gun	259
	Y. Yang, B.T. Li, X.Y. Lu, W.W. Tan, L. Xiao, D.Y. Yang, Z.Q. Yang, J. Zhao PKU, Beijing, People's Republic of China
	X-ray is now widely used in many areas of physics, biology, chemistry and materials. And how to achieve emission, monochrome, and focusing of x-ray is of great significance to study. Micro-pulse electron gun (MPG) is a new type of electron source, with characteristics of high repetition frequency, short-pulse and low cost. Generating x-ray with better monochromaticity is one of the potential applications of MPG. And a preliminary scheme of X-ray based on MPG is proposed in this paper. The scheme is designed by comparing different anode materials and the thickness of filters. The simulation results based on the software MCNP5 show that the proposed scheme can effectively improve the monotonicity of the generated X-rays.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB082
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MOPB086	First Results of the IFMIF/EVEDA-SaTHoRI Tests	262
	O. Piquet, N. Bazinpresenter, P. Carbonnier, J.K. Chambrillon, M. Desmons, G. Devanz, H. Jenhani, C. Servouin CEA/DRF/IRFU, Gif-sur-Yvette, France P. Cara Fusion for Energy, Garching, Germany J.F. Denis, L. Maurice, J. Relland CEA/IRFU, Gif-sur-Yvette, France F. Éozénou, P. Hardy, E. Jacques, Y. Lussignol, P. Sahuquet CEA/DSM/IRFU, France D. Gex, A. Jokinen, G. Phillips F4E, Germany I. Moya, P. Méndez CIEMAT, Madrid, Spain
	The SaTHoRI test stand (Satellite de Tests Horizontal des Résonateurs IFMIF) aims to characterize a jacketed and fully dressed cavity with its coupler and tuner. A dedicated test cryostat has been manufactured and is connected to an existing horizontal test cryostat which provides the cryogenic coolant. A RF source ' provided by the IFMIF collaboration, one of the four RF sources which will be used for the cryomodule at Rokkasho ' has been installed and commissioned at CEA. This paper describes the test stand and presents the first results.
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MOPB087	Frequency Tuner Development and Testing at Cornell for the RAON Half-wave-resonator	266
	M. Ge, F. Furuta, J.E. Gillette, T. Gruber, S.W. Hartman, M. Liepe, T.I. O'Connell, P.J. Pamel, P. Quigley, J. Sears, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA B.H. Choi, J. Joo, J.W. Kim, W.K. Kim, J. Lee, I. Shin IBS, Daejeon, Republic of Korea
	The half-wave-resonators (HWRs) for the RAON project require a slow frequency tuner that can provide >80 kHz tuning range. Cornell University is currently in the process of designing, prototyping, and testing this HWR tuner. In this paper, we present the optimized tuner design, prototype fabrication, test insert preparation, and cryogenic test results. The performance of the tuner is analysed in detail.
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MOPB088	Experience on In-situ Module Repair and Set Up of Non XFEL Cavity Strings at DESY	269
	M. Schmökel, A. Daniel, N. Krupka, A. Matheisen, S. Saegebarth, M. Schalwat, P. Schilling DESY, Hamburg, Germany
	All components installed to the European XFEL cavity string modules underwent an intensive inspection and quality control before acceptance for installation to cavities or modules. Even though some RF feed throughs for HOM coupler- and Pick Up antennas showed leaks at the ceramic insulation after module test at 2 K. Due to time restriction and continuity of production the exchange of these parts needed to be done without reentering the cleanroom. Successful repair of these modules took place by setting up a local cleanroom onto the cavity string. In collaboration with Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a cavity string for the ELBE project was assembled at DESY and transported to HZDR for installation to the vacuum vessel. A spare module with 3.9 GHz Resonators for the European XFEL was set up at DESY and will be tested and qualified for the European XFEL. Due to delay in delivery of the power couplers, four power couplers were installed after string assembly.
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MOPB089	Characterisation of Magnetic Shielding Material for HL-LHC Crab Cavities	273
	K. Eiler, P. Arpaia, M.C.L. Buzio, O. Capatina, S.A.E. Langeslag, A. Parrella CERN, Geneva, Switzerland P. Arpaia, A. Parrella Naples University Federico II, Science and Technology Pole, Napoli, Italy A. Parrella IT, Lisboa, Portugal N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: CERN, 1211 Geneva 23 To guarantee optimum performance, the crab cavities for the high-luminosity upgrade of CERN's LHC need to be shielded from external magnetic fields. Consequently, they will be enclosed by two layers of magnetic shielding, of which the inner is immersed in superfluid helium at 2 K. A Ni-based high-permeability material with a tailored composition and a designated heat treatment is applied. Its magnetic properties at cryogenic temperature are however not yet fully assessed. Especially the effect of deformation on magnetic properties has not been thoroughly investigated, however strain effects may have severe consequences. A magnetic measurement set-up has been developed, and the magnetic permeability at room temperature and at cryogenic temperatures is evaluated, showing that the maximum relative permeability at 4 K exceeds the design criteria of 100, 000. Measurements of the magnetic permeability after introduction of uniaxial plastic deformation between 0% and 3% are conducted by means of an Epstein frame. Results show that deformation induces significant decrease of the magnetic performance, underlining that particular care must be taken during all stages of handling and operation. *konrad.eiler@cern.ch
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MOPB090	Sub-micro-Tesla Magnetic Shielding Design for Cryomodules in the High-gradient Program at CERN	278
	S. Papadopoulos, L. Dassa, F. Gerigk, F. Pillon, S. Ramberger, P. Yilmazer CERN, Geneva, Switzerland J. Dequaire Intitek, Lyon, France
	In the framework of the High-Gradient R\&D program at CERN a cryomodule, consisting of four superconducting 5-cell cavities, has been designed. In order to reduce flux trapping in the surface of the superconductor and to minimize Q degradation during a quench, highly effective magnetic shielding is needed. The solution proposed includes cold and warm passive shielding enhanced by four compensating coils. In this paper the magneto-static simulation results are presented illustrating different design considerations that led to a final design. Finally the shielding ability of the vacuum vessel is investigated experimentally through ambient magnetic field measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB090
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MOPB094	Commissioning of Demonstrator Module for CW Heavy Ion LINAC@GSI	283
	V. Gettmann, K. Aulenbacher, W.A. Barth, F.D. Dziuba, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, M. Heilmann, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia M. Basten, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	The cw - Linac - demonstrator is a prototype of the first section of the proposed cw-LINAC@GSI, comprising a superconducting CH-cavity embedded by two superconducting solenoids. The sc CH-structure is the key component and offers a variety of research and development. The beam focusing solenoids provide maximum fields of 9.3 T at an overall length of 380 mm and a free beam aperture of 30 mm. The magnetic induction at the fringe is minimized to 50 mT at the inner NbTi-surface of the neighboring cavity. The fabrication of the key components is finished, as well as the cold performance testing of the RF cavity. The cryostat is ready for assembling and the test environment is completely prepared. After successful testing of the RF-Power coupler, the components will be assembled to the suspended frame under cleanroom conditions. Alignment, assembly, under cleanroom condition issues will be presented.
	Poster MOPB094 [2.881 MB]
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MOPB096	Estimation of Alignment Error by Measuring Higher-order-mode of Injector Superconducting Cavity at KEK-cERL	286
	Y. Honda, E. Kako, T. Konomi, T. Miyajima, T. Obina, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	Precise alignment of accelerator cavities is important in realizing a low emittance beam. Especially in the cases of superconducting cavities installed in a cryomodule, it is difficult to mechanically measure the position of the cavities. By measuring higher-order-modes (HOM) excited by a beam, the electrical center of the cavities can be estimated. We have developed a HOM measurement system for the injector superconducting accelerator cavities of KEK ERL test accelerator (cERL).Comparing the HOM signals of the three independent cavities in the cryomodule, we estimated the relative positioning errors of the three cavities.
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MOPB097	Degradation and Recovery of Cavity Performances in Compact-ERL Injector Cryomodule	289
	E. Kako, T. Konomi, T. Miura, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	Injector cryomodule for cERL consists of three 2-cell cavities equipped with double-feeds input couplers, five antenna-type HOM couplers and a slide-jack tuner with two piezo actuators. After cryomodule assembly and first cool-down tests in 2012, the cERL injector cryomodule has been stably operated with beam for four years. Gradual increases of x-ray radiation levels due to field emission were observed during long term beam operation. High power pulsed RF conditioning as a cure method was applied in the cool-down period in 2016 and 2017, so that degraded cavity performances have almost recovered up to the original levels. Performance recovery status in three 2-cell cavities will be reported in this paper.
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MOPB099	Design of C-ADS Injector-I Cryomodule for 325MHz Cavities	294
	R. Ge, L. Bian, R. Han, S.P. Li, M.J. Sang, L.R. Sun, M.F. Xu, R. Ye, J.Q. Zhang, J.H. Zhang, X.Z. Zhang IHEP, Beijing, People's Republic of China
	Funding: Supported by Strategic Priority Research Program of CAS (XDA030213) The Chinese Accelerator Driven Sub-critical system (C-ADS) uses a high energy proton beam to bombard the metal target and generate neutrons to deal with the nuclear waste. The Chinese ADS proton linear has two 0~10 MeV injectors and one 10~1500 MeV superconducting linac. Injector-I is studied by the Institute of High Energy Physics (IHEP) under construction in the Beijing, China. The linear accelerator consists of two accelerating cryomodules operating at the temperature of 2 Kelvin. This paper describes the structure and thermal performances analysis of the cryomodule. The analysis takes into account all the main contributors (support posts, multilayer insulation, current leads, power couplers, and cavities) to the static and dynamic heat load at various cryogenic temperature levels. The thermal simulation analysis of the cryomodule is important theory foundation of optimization and commissioning.
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MOPB101	Cryomodule Fabrication and Modification for High Current Operation at the Mainz Energy Recovering Superconducting Accelerator MESA	297
	T. Stengler, K. Aulenbacher, F. Hug, D. Simon IKP, Mainz, Germany K. Aulenbacher, T. Kürzeder HIM, Mainz, Germany
	Funding: This work is supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA" EXC 1098/2014} At Johannes Gutenberg-Universität Mainz, the Institute for Nuclear Physics is currently building the multiturn ERL 'Mainz Energy-Recovering Superconducting Accelerator' MESA. The §I{1.3}{\giga\hertz} cryomodules are based on the ELBE modules at Helmholtz Center Dresden-Rossendorf (HZDR) but are modified to suit the high current, energy recovering purposes of MESA. With two 9-cell TESLA cavities each, they shall provide §I{50}{\mega\electronvolt} energy gain per turn. The design and fabrication was done by Research Instruments GmbH, Bergisch Gladbach, Germany. The current status of the cryomodules, the test set up at the Helmholtz-Institute Mainz, the cavity properties and their tests will be discussed.
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MOPB102	Preliminary Design on the Cryomodule of the HWR for the Secondary Particle Generation at KOMAC	301
	H.-J. Kwon, Y.-S. Cho, J.J. Dang, H.S. Kim, K.H. Kim, S. Lee, Y.G. Song Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
	Funding: This work has been supported through KOMAC (Korea of Multi-purpose Accelerator Complex) operation fund of KAERI by MSIP (Ministry of Science, ICT and Future Planning). A 100 MeV proton linac based on the radio frequency quadrupole and conventional drift tube linac has been operating for user service at KOMAC (Korea Multi-purpose Accelerator Complex). A superconducting linac based on the half-wave resonator is studied in order to increase the proton energy from 100 MeV to 160 MeV for secondary particle generation such as neutron. A cryomodule and its cryogenics were designed. The operating temperature of the HWR is 2 K. One cryomodule contains four HWR cavities and it didn't have superconducting solenoid because a doublet lattice using normal conducting magnet was considered as focusing elements. A thermal design was conducted and the structure was designed based on the existing well proven technologies. The results of the design on the cryomodule and cryogenics for KOMAC HWR are summarized and discussed in the conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB102
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MOPB104	Development of a Novel Supporting System for High Luminosity LHC SRF Crab Cavities	304
	T.J. Jones STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom K. Artoos, R. Calaga, O. Capatina, T. Capelli, M. Sosin, J.S. Swieszek, C. Zanoni CERN, Geneva, Switzerland G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T.J. Jones Lancaster University, Lancaster, United Kingdom
	Compact SRF Crab Cavities are integral to the HL-LHC upgrade. This paper details the design of support structures within the SPS (Super Proton Synchrotron) Crab Cavity Cryomodule. For ease of alignment each cavity is supported with the mechanical tuner and RF Fundamental Power Coupler (FPC) via a common support plate. To reduce heat leak and remove bellows in the FPC it was determined that this would be the fixed support for the cavity (V. Parma, 2013). In addition, novel flexural blades were designed to give increased stiffness yet allow for thermal contraction of the cavity towards the fixed point of the FPC. This approach was superior when compared via simulation to several alternative techniques. A detailed simulation model was used for optimisation of directional stiffness, identification of vibration modes and minimising thermal stresses. A transmission matrix was developed in MS Excel to assess modal deflection for given ground vibration conditions. The spreadsheet gives an instantaneous yet comparable result to time consuming random vibration FE Analyses. The final engineering design of the supporting system is now complete and will also be described in this paper. References V. Parma, R. B. (2013). Status of the Superconducting Proton Linac (SPL) Cryomodule. SRF2013.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB104
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MOPB105	Thermosiphon Cooling Loops for ARIEL Cryomodules	309
	Y. Ma, A.N. Koveshnikov, D. Lang, R.E. Laxdal, N. Muller TRIUMF, Vancouver, Canada
	Thermosiphon cooling loops have been used in ARIEL[1,2] cryomodules for 1.3GHz superconducting cavities cooling. It can deliver 4K liquid Helium from 4K phase separator to cavity thermal intercepts and return the vaporized liquid to the 4K phase separator as a refrigerator load. The design and test results are presented in this paper.
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MOPB106	Test Results of the European XFEL Serial-production Accelerator Modules	312
	K. Kasprzak, M. Wiencek, A. Zwozniak IFJ-PAN, Kraków, Poland D. Kostin, D. Reschke, N. Walker DESY, Hamburg, Germany
	The serial-production tests of 100 cryomodules for the European XFEL have been finished. In this paper the statistics of the cold RF measurements in the AMTF (Accelerator Module Test Facility) are reported for all the modules. In addition comparison between the cavity vertical test results and module test results are presented.
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MOPB109	LCLS-II Cryomodule Transport System Testing	317
	N.A. Huque, E. Daly JLab, Newport News, Virginia, USA M.W. McGee Fermilab, Batavia, Illinois, USA
	The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.
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MOPB110	Results of Accelerated Life Testing of LCLS-II Cavity Tuner Motor	323
	N.A. Huque, E. Daly JLab, Newport News, Virginia, USA Y.M. Pischalnikov Fermilab, Batavia, Illinois, USA
	An Accelerated Life Test (ALT) of the Phytron stepper motor used in the LCLS-II cavity tuner has been conducted at JLab. Since the motor will reside inside the cryomodule, any failure would lead to a very costly and arduous repair. As such, the motor was tested for the equivalent of 30 lifetimes before being approved for use in the production cryomodules. The 9-cell LCLS-II cavity is simulated by disc springs with an equivalent spring constant. Plots of the motor position vs. tuner position ' measured via an installed linear variable differential transformer (LVDT) ' are used to measure motor motion. The titanium spindle was inspected for loss of lubrication. The motor passed the ALT, and is set to be installed in the LCLS-II cryomodules.
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MOPB111	European XFEL Linac RF System Conditioning and Operating Test	328
	D. Kostin, J. Branlard, A. Gössel, O. Hensler, M. Omet, D. Reschke, A.A. Sulimov, N. Walker, M. Wiencek DESY, Hamburg, Germany
	96 accelerating modules with 768 TESLA/European-XFEL type superconducting cavities were installed in the European XFEL LINAC tunnel (XTL) in the fall 2016. Warm conditioning of the RF system - High/Low Level RF System and main input couplers - begun even before finishing the accelerator installation works. All modules were conditioned and tested prior to the installation in the tunnel in the AMTF test stand at DESY. Nevertheless, due to some repair activities on warm input coupler parts, warm conditioning was needed on a few modules/couplers. Cooling down to 2K begun in December 2016 and was finished in January 2017. Since then cold conditioning and tests are running. Several cavities in a few modules did show the multipacting (MP) effects, mostly because a cavity vacuum was filled with a dry nitrogen for before mentioned repairs on couplers in some modules. Said MP effects were seen in AMTF as well. All MP effects were successfully conditioned until now. The warm/cold RF system conditioning and its results/experiences/limits are described and discussed.
	Poster MOPB111 [1.267 MB]
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Paper

Title

Page

Concepts and Design for Beamline HOM Dampers for eRHIC

39

P. Kolb, Y. Gao, D. Holmes, K.S. Smith, W. Xu
BNL, Upton, Long Island, New York, USA
Y. Gao
PKU, Beijing, People's Republic of China

Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
In the design of eRHIC at BNL, HOM power plays a major role for the SRF installation. Depending on the final accelerator design and choice of cavity, up to 100kW of HOM power is estimated to be generated, presenting a big challenge for the HOM damping concept. Due to this high amount of HOM power, all current concepts for eRHIC would use room temperature beam line absorbers equipped with silicone-carbide dielectrics to absorb HOM power. Concepts, designs and simulations for these beam line absorbers will be presented.

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MOPB002

eRHIC Crab Cavity Choice for Ring-ring Design

43

Q. Wu, I. Ben-Zvi, Y. Hao, S. Verdú-Andrés, B. P. Xiao
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The future electron ion collider eRHIC adopts large crossing angle (22 mrad) to allow fast separation of two beams in the ring-ring scheme. Crab cavities are required to recover the luminosity from geometric losses. Initial calculation shows that the frequency of the cavities for the ion beam is no more than 336MHz. In this paper, we discuss the crab cavity related lattice parameters for both ion and electron beams in ring-ring design, the frequency choice, and the cavity design considerations.

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MOPB003

A New High Resolution Optical System for Inspection of Gun-and Multi-cell Resonators in ISO-4 Cleanrooms

47

M. Schalwat, R. Bandelmann, A. Daniel, N. Krupka, A. Matheisen, S.T. Sieverspresenter
DESY, Hamburg, Germany

Optical inspection of the inner surface of superconducting resonators was established during European XFEL cavity production by usage of the so called OBACHT optical inspection. In addition to the surface inspection by OBACHT a new optical inspection system with integrated high resolution camera is set up at DESY. It allows inspection of multi-cell resonators as well as gun cavity resonators with only single side accessibility to the inner surface. A prototype was commissioned and optical inspections were done with OBACHT and the new system in parallel. Two SRF gun cavities were inspected by this optical system and origin of limitations of the resonators were identified.

Poster MOPB003 [0.220 MB]

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MOPB004

Design of a RF Quadrupole Resonator for Landau Damping in HL-LHC

51

K. Papke, A. Grudiev
CERN, Geneva, Switzerland

The design and optimization of a quadrupole resonator for transverse Landau damping in the High Luminosity Large Hadron Collider (HL-LHC) is presented. Two different cavity types are considered whose shape is determined by quadrupolar strength, surface peak fields, and beam coupling impedance. The lower order and higher order mode (LOM and HOM) spectra of the optimized cavities are investigated and different approaches for their damping are proposed. Along an example, the required RF power and optimal external quality factor for the input coupler is derived.

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MOPB005

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

56

M. Schwarz, M. Basten, M. Busch, H. Podlech, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany
W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia
W.A. Barth, M. Heilmann, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany

Funding: Work supported by BMBF contr. No. 05P15RFRBA
For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI, HIM and IAP is currently in progress. It aims at developing a superconducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the upgraded High Charge Injector (HLI) at GSI. The LINAC design is challenging, due to the requirement of intense beams in CW-mode up to a mass-to-charge ratio of 6 while covering a broad output energy range from 3.5 to 7.3 MeV/u with minimum energy spread. After sucessful tests with the first CH cavity in 2016 demonstrated a promising maximum accelerating gradient of E_a = 9.6 MV/m, recently first beam tests have been started as next milestone at GSI, confirming its flawless functionality*.
W. Barth et al., Further Layout Investigations for a Superconducting CW-linac for Heavy Ions at GSI, 18th Int. Conf. on RF Superconductivity (SRF17), Lanzhou, China, July 2017, paper MOPB023.

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MOPB007

Design of the Superconducting Quarter Wave Resonators for HIAF

59

C. Zhang, L. Chen, Q.W. Chu, H. Guo, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, L. Li, Y.M. Li, F. Pan, T. Tan, R.X. Wang, A.D. Wu, Q.J. Wu, P.R. Xiong, W.M. Yue, S.H. Zhang, S.X. Zhang
IMP/CAS, Lanzhou, People's Republic of China

A heavy ion accelerator facility (HIAF) is under development in the Institute of Modern Physics. For the low energy superconducting accelerating section, two types of quarter wave resonators with frequency of 81.25 MHz and β of 0.05 and 0.10 have been proposed. The electro-magnetic design has been optimized in order to reach the high accelerating voltage, and the optimization also included the drift tube face tilting to compensate for the beam steering caused by the asymmetry in the quarter wave resonator geometry.

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MOPB008

Input Power Coupler for NICA Injector Coaxial Quater Wave SC Cavity

61

M.V. Lalayan, T.A. Bakhareva, M. Gusarovapresenter, S.V. Matsievskiy
MEPhI, Moscow, Russia

New coaxial power coupler research and development results are presented and discussed. Coupler is proposed for superconducting QWR cavities being under consideration now as option for planned Nuclotron-based Ion Collider fAcility (NICA) injector upgrade. The goal was to develop power coupler operating at 162 MHz and feeding SC cavity with about 20 kW RF power. It provides Qext tuning range (1.5-3)E5 by inner conductor movement. Conservative design with two identical disk ceramic windows was chosen. Electrodynamic, thermal and mechanical simulations were carried out.

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MOPB009

Progress of 650 MHz SRF Cavity for eRHIC SRF Linac

64

W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, C. Pai, R. Porqueddu, K.S. Smith, R. Than, J.E. Tuozzolo, F.J. Willeke, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, 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.
eRHIC ERL SRF requires 160 5-cell 650 MHz SRF cavities. The 650 MHz cavity has been designed and two prototypes have been fabricated, one Cu cavity for HOM study and one Nb cavity for cavity performance study. This paper will describe cavity design and the progress of prototyping.

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MOPB010

Design of the 2×4-cell Superconducting Cryomodule for the Free-electron Laser

67

X. Luo, C.L. Lao, M. Li, L.J. Shan, X.M. Shen, H. Wang, X. Yang, K. Zhoupresenter
CAEP/IAE, Mianyang, Sichuan, People's Republic of China
X.Y. Lu, S.W. Quan, F. Wang
PKU, Beijing, People's Republic of China

A 2×4-cell superconducting linac module for the THz-FEL facility has been developed at the China Academy of Engineering Physics, which is expected to provide 6~8 MeV quasi-CW electron beams with an average current of 1~5 mA. The design of the cryomodule is presented in this paper. The dynamic and static heat load have been evaluated to reasonable level. The temperature distribution inside the cryomodule has been optimized by simulation, as well as mechanical structure and the magnetic shielding.

Poster MOPB010 [1.019 MB]

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MOPB011

CEA Cryomodules Design for SARAF Phase 2

70

C. Madec
CEA, Gif-sur-Yvette, France
N. Bazin, D. Chirpaz-Cerbat, R. Cubizolles
CEA/IRFU, Gif-sur-Yvette, France
P. Brédy
CEA/DSM/IRFU, France
R. Bruce, P. Hardy, F. Leseigneur, Th. Plaisant, J. Plouin
CEA/DRF/IRFU, Gif-sur-Yvette, France

CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40.1 MeV. The SCL consists in 4 cryomodules separated by warm diagnostics housing beam diagnostics. The first two identical cryomodules host 6 half-wave resonator (HWR) low beta cavities (β = 0.091), 176 MHz. The last two identical cryomodules are equipped with 7 HWR high-beta cavities (β = 0.181), 176 MHz. The beam is focused through superconducting solenoids located between cavities housing steering coils. A Beam Position Monitor is placed upstream each solenoid. A diagnostic box containing a beam profiler and a vacuum pump will be placed at the end of each cryomodule. The cryomodules and the warm sections are being designed. These studies will be presented in this poster.

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MOPB012

Status of the IFMIF LIPAc SRF Linac

74

N. Bazin, C. Boulch, A. Bruniquel, P. Carbonnier, J.K. Chambrillon, G. Devanz, F. Éozénou, P. Hardy, H. Jenhani, O. Piquet, J. Plouin, A. Riquelme, D. Roudier, C. Servouin
CEA/DRF/IRFU, Gif-sur-Yvette, France
P. Charon, S. Chel, G. Disset, L. Maurice, J. Relland, B. Renard
CEA/IRFU, Gif-sur-Yvette, France
P. Contrepois
CEA/DSM/IRFU, France
D. Regidor, F. Toral
CIEMAT, Madrid, Spain

The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz and eight focusing solenoids. This paper presents the status of the IFMIF SRF Linac.

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MOPB013

European XFEL Input Coupler Experiences and Challenges in a Test Field

78

F. Hoffmann, D. Kostin, W.-D. Möller, D. Reschke, M. Wiencek
DESY, Hamburg, Germany

102 European XFEL accelerating modules with 816 superconducting cavities and main input RF power couplers were assembled and then tested at DESY prior to installation in the European XFEL tunnel. In the Accelerating Module Test Facility (AMTF) warm and cold RF tests were done. The test results went directly to the operational setup for the LINAC. Main input couplers did present several problems during the tests, resulting in some minor coupler design changes as well as in a few repair actions. The experience got from the said testing operation is worth to be shared and is presented here together with a discussion.

Poster MOPB013 [0.648 MB]

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MOPB015

Accelerator Module Repair for the European XFEL Installation

82

E. Vogel, S. Barbanotti, F. Hoffmann, K. Jensch, D. Kostin, L. Lilje, W.-D. Möller, M. Schmökel, H. Weise
DESY, Hamburg, Germany
S. Berry, O. Napoly
CEA/DSM/IRFU, France
M. Sienkiewicz, J. Świerbleski, M. Wiencek
IFJ-PAN, Kraków, Poland

Repair actions of different extent have been performed at 61 modules of the 100 accelerating series modules for the European XFEL to qualify them for the tunnel installation. Four modules could not be repaired in time. CEA Saclay managed to perform three major repairs in parallel to the series module integration, the residual repair actions took place at DESY Hamburg. In this paper we will give an overview on the various technical problems which required being fixed before the tunnel installation and on the repair actions performed.

Poster MOPB015 [9.354 MB]

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MOPB016

Operation of Diamond Superconducting RF Cavities

87

P. Gu, C. Christou, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink
DLS, Oxfordshire, United Kingdom

The Diamond Light Source storage ring has been in operation using superconducting RF cavities since 2007. Diamond has four superconducting cavity modules with two usually installed at any one time. The four cavities perform differently in many aspects such as reliable operating parameters and time in service, with the longest in continuous service for 7 years without failure and the shortest failing after only 8 months. All Diamond superconducting RF cavities suffered many fast vacuum trips in their early years, but after many years of efforts, the performance of the cavities have now been effectively managed by weekly conditioning, partial warm-up during shut down and cavity voltage level control. We will discuss our experience with superconducting RF cavities and our future plan.

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MOPB017

Multiphysics Simulations of the Wide Opened Waveguide Crab-cavity

90

K. Papke, A. Amorim Carvalho, A. Grudiev, C. Zanoni
CERN, Geneva, Switzerland

In the frame of a FCC study a first prototype of a compact superconducting crab-cavity, using Nb-on-Cu-coating technique is being manufactured and investigated. The design, which is based on the ridged waveguide resonator, is subjected to multipacting and pressure sensitivity simulations. First results of theses simulations are presented and compared to those of other SRF cavities. Furthermore, several aspects related to the design of the fundamental mode coupler and HOM dampers are presented.

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MOPB018

Testing of SRF Cavities and Cryomodules for the European Spallation Source

95

N. Elias, E. Asensi Conejero, C. Darve, N.F. Hakansson, W. Hees, C.G. Maiano, F. Schlander
ESS, Lund, Sweden

The European Spallation Source (ESS) is currently under construction in Lund, Sweden. The ESS linear accelerator aims to deliver a 62.5 mA , 2.86 ms long proton beam onto a rotating tungsten target, at 14 Hz repetition rate, thus achieving an energy of 2 GeV and 5 MW power. Most of the beam acceleration happens in the superconducting fraction of the linac, which is composed of three sectors of cryomodules named after the cavities housed within. The first sector of the SRF linac is composed of 13 Spoke cryomodules containing 2 double-spoke cavities with a geometric beta of 0.5, the second is composed of 9 medium beta cryomodules each housing four elliptical cavities (β=0.67) and finally 21 high beta cryomodules enclosing four elliptical cavities (β=0.86). ESS has strategically built up a SRF collaboration with other European institutions, these partners will deliver through In-Kind agreements cavities and cryomodules performing within the ESS specification. This article describes the process leading to the acceptance of cavities and cryomodules received from the different partners and the necessary testing required prior to the final installation in the ESS tunnel.

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MOPB019

Interface Challenges for the SRF Cryomodules for the European Spallation Source

100

F. Schlander, C. Darve, N. Elias, C.G. Maiano
ESS, Lund, Sweden
P. Bosland
CEA/DSM/IRFU, France
G. Olry
IPN, Orsay, France

The European Spallation Source is currently under construction in Lund in southern Sweden. The main part of the accelerator will consist of two different types of cryomodules housing three different types of cavities ' double spoke cavities and two different elliptical cavities. The spoke cavities as well as the cryomodules will be provided by IPN Orsay, thus the external interfaces to the other accelerator systems have to be verified. While the procurement and assembly of the elliptical cryomodules will be performed by CEA Saclay, the cavities will be provided by INFN Milano and STFC Daresbury. Thus in addition to the external cryomodule interfaces, also the internal interfaces between cavities and cryomodules have to be taken care of. This contribution presents the challenges related to this work.

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MOPB020

An Optimal Procedure for Coupler Conditioning for ESS Superconducting Linac

103

H. Li
Uppsala University, Uppsala, Sweden
E. Asensi Conejero, C.G. Maiano, R. Zengpresenter
ESS, Lund, Sweden

An optimal procedure for coupler and cavity conditioning is proposed for the ESS superconducting cavities, which is applicable for different test stands and following installation in the ESS tunnel. A preliminary procedure has been developed and successfully tested at FREIA facility, Uppsala. The preliminary procedure will now be improved by integrating it into LLRF and EPICS control. This will be a joint effort between FREIA and ESS and will be used at the test stands in Lund and on the couplers installed in the tunnel. Developing the conditioning procedures on a common platform offers ESS significant advantages by allowing the procedures to be reused at different sites and by recording data in a consistent format. The details of the procedure, its development and testing will be reported and the future activities will be described.

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MOPB023

Further Layout Investigations for a Superconducting CW-linac for Heavy Ions at GSI

108

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

Very compact accelerating-focusing structures, as well as short focusing periods, high accelerating gradients and very short drift spaces are strongly required for superconducting (sc) accelerator sections operating at low and medium beam energies. To keep the GSI-Super Heavy Element program competitive on a high level and even beyond, a standalone sc continuous wave Linac in combination with the GSI High Charge State injector, upgraded for cw-operation, is envisaged. The first LINAC section (financed by HIM and GSI) as a demonstration of the capability of 216 MHz multi gap Crossbar H-structures (CH) is still in the beam commissioning phase, while an accelerating gradient of 9.6 MV/m (4 K) at a sufficient quality factor has been already reached. Recently the overall Linac design, based on a standard cryomodule, comprising three CH cavities, a rebuncher section and two 9.3 T-solenoidal lenses, has to be fixed. This paper presents the status of the Linac layout studies as well as the integration in the GSI accelerator facility.

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MOPB024

Steps Towards Superconducting CW-linac for Heavy Ions at GSI

112

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

A superconducting (sc) cw-Linac at GSI should ensure competitive production of Super Heavies in the future. Further R&D for this cw-Linac, a so called 'Advanced CW-Demonstrator', with maximal energy of 3.5 MeV/u is ongoing. As a first step, the demonstrator project with one sc CH-cavity is near its completion, the beam tests are scheduled for mid-summer 2017. The completion of the 'Advanced CW-Demonstrator' includes successive construction of two new cryogenic modules comprising four CH-cavities and two solenoids each. In this contribution the layout of the cryomodules and the Helium distribution system are presented.

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MOPB028

HOM Coupler Design for CEPC Cavities

115

H.J. Zheng, F. Meng, J.Y. Zhai
IHEP, Beijing, People's Republic of China

Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400)
In this paper，it will be presented the higher order mode (HOM) coupler design for the Circular Electron-Positron Collider (CEPC) 650 MHz 2-cell cavity. The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. A double notch coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe. This paper summarizes the RF design of the HOM coupler, tolerance analysis, thermal analysis as well as mechanical structures.

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MOPB031

Fabrication and Cold Test Result of FRIB β=0.53 Pre-production Cryomodule

120

H. Ao, J. Asciutto, B. Bird, N.K. Bultman, E.E. Burkhardt, F. Casagrande, C. Compton, K.D. Davidson, K. Elliott, A. Ganshyn, I. Grender, W. Hartung, L. Hodges, I.M. Malloch, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarskipresenter, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, S. Stark, J.D. Wenstrom, M. Xu, T. Xu, Z. Zheng
FRIB, East Lansing, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The driver linac for the Facility for Rare Isotope Beams (FRIB) comprises four kinds of cavities (β=0.041, 0.085, 0.29, and 0.53) and six types of cryomodules including matching modules. FRIB has completed the fabrication and the cold test of a β=0.53 pre-production cryomodule, which is the first prototype for a half-wave (β=0.29 and 0.53) cavity. This paper describes the fabrication and the cold test result of the β=0.53 pre-production cryomodule including lessons learned.

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MOPB034

Selection of the Type of Accelerating Structures for the Second Group of Cavity SC Linac Nuclotron-NICA

125

M. Gusarova, A.A. Gorchakov, M.V. Lalayan, D.V. Surkov, K.V. Taletskiy
MEPhI, Moscow, Russia
A.V. Butenko
JINR/VBLHEP, Dubna, Moscow region, Russia
D.A. Shparla
Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
A.O. Sidorin, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia

The paper summorises the research results aimed on the choice of superconducting accelerating cavities for the second section of the SC linac Nuclotron-NICA injector project. This choice was based on comparative analysis of accelerating structures electrodynamic characteristics taking into account technological challenges of bulk niobium cavities production.

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MOPB035

Cryogenic Probe Station at Old Dominion University Center for Accelerator Science

128

J. Makita, J.R. Delayen, A.V. Gurevich
ODU, Norfolk, Virginia, USA
G. Ciovati
JLab, Newport News, Virginia, USA

With a growing effort in research and development of an alternative material to bulk Nb for a superconducting radiofrequency (SRF) cavity, it is important to have a cost effective method to benchmark new materials of choice. At Old Dominion University's Center for Accelerator Science, a cryogenic probe station (CPS) will be used to measure the response of superconductor samples under RF fields. The setup consists of a closed-cycle refrigerator for cooling a sample wafer to a cryogenic temperature, a superconducting magnet providing a field parallel to the sample, and DC probes in addition to RF probes. The RF probes will extract a quality factor from a sample patterned in a coplanar waveguide resonator structure on a 2' wafer. From the measured quality factor, the surface resistance and the penetration depth as a function of temperature and magnetic field will be calculated. This paper will discuss the design and measurement procedures of the current CPS setup.

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MOPB036

The Study of Deposition Method of Nb3Sn Film on Cu Substrate

131

L. Xiao, X.Y. Lu, W.W. Tan, D. Xie, D.Y. Yang, Y. Yang, Z.Q. Yang, J. Zhao
PKU, Beijing, People's Republic of China

Our work is mainly focused on the fabrication methods of Nb3Sn films on Cu substrates and film's properties. There are diffraction peaks of Nb3Sn in the X-ray diffraction patterns in which without diffraction peaks of copper compounds. Scanning electron microstructures of Nb3Sn film reflect its nice compactness and binding force between film and substrate.

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MOPB037

Progress of the 2x4-Cell Superconducting Accelerator for the CAEP THz-FEL Facility

134

K. Zhou, C.L. Lao, M. Li, X. Luo, L.J. Shan, X. Shen, H. Wang, X. Yang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China
X.Y. Lu
PKU, Beijing, People's Republic of China

The high average power THz radiation facility is now under construction in China Academy of Engineering Physics. The superconducting accelerator is one of the most important components for this facility, including two 4-Cell TESLA superconducting radio frequency cavities. The designed effective field gradients for both cavities are 10^-12 MV/m. This paper will present the progress of the 2x4-cell superconducting accelerator, mainly including its construction and cryogenic test in Chengdu. At 2 K state, the cryomodule works smoothly and stably. The effective field gradients of both cavities have achieved 10 MV/m. Further beam loading experiments are now in progress.

Poster MOPB037 [5.124 MB]

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MOPB040

ESS High-beta Cavity Test Preparations at Daresbury Laboratory

137

P.A. Smith, L. Bizel-Bizellot, K.D. Dumbell, M. Ellis, P. Goudket, A.J. Moss, E.F. Palade, S.M. Pattalwar, M.D. Pendleton, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Science and Technology Facility Council is responsible for supplying, and testing 84 High beta elliptical SRF cavities, as part of the UK In Kind Contribution to the European Spallation Source (ESS). The High-β=0.86, cavities have been designed by CEA- Saclay and are a five cell Niobium cavity operating at 704.42 MHz. They are required to provide an accelerating gradient of 19.9 MV/m at an unloaded Q of 5x10⁹. Preparations are underway to upgrade the cryogenic and RF facilities at Daresbury laboratory prior to the arrival of the first cavities. As part of these arrangements, a niobium coaxial resonator has been manufactured, to validate the test facility. The design considerations, for the coaxial resonator are presented, along with preliminary results. The RF measurement system to perform the cavity conditioning and testing is also presented.

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MOPB041

Status of the SOLEIL Superconducting RF System

141

M. Diop, J.P. Baete, R.C. Cuoq, H.D. Dias, J.L. Labelle, L.R. Lopes, M. Louvet, P. Marchand, C.M. Monnot, S. Petit, F. Ribeiro, T. Ruan, R. Sreedharan, K.T. Tavakoli
SOLEIL, Gif-sur-Yvette, France

The 352 MHz SOLEIL SRF systems consist in two cryomodules, each containing a pair of SC Nb/Cu cavities, cooled with LHe at 4K from a single 350 W cryogenic plant. In order to store 500 mA, a power of 575 kW and an accelerating voltage of 3-4 MV are required. The RF power is provided by 4 SSPA's delivering up to 180 kW each. The original cavity input power couplers, which are LEP-type antennas designed to handle up to 200 kW, are being replaced by upgraded versions, able to operate at 300 kW CW. This will open the possibility to operate at full beam current with only one active cryomodule. The SRF system operational experience over the past ten years as well as the different upgrades will be reported here.

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MOPB042

The TRIUMF/VECC Injector Cryomodule Performance

144

Y. Ma, K. Fong, T. Junginger, D. Kishi, A.N. Koveshnikov, R.E. Laxdalpresenter, N. Muller, R.R. Nagimov, D.W. Storey, E. Thoeng, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada
U. Bhunia, A. Chakrabarti, S. Dechoudhury, V. Naik
VECC, Kolkata, India

The collaboration on superconducting electron Linac for rare ion beam facilities ARIEL (Advanced Rare Iso-topE Laboratory) [1-4] and ANURIB [5] (Advanced Na-tional facility for Unstable and Rare Isotope Beams) has resulted in production of a superconducting Injector Cryomodule (VECC ICM) at TRIUMF for VECC. The cryomodule design utilizes a unique box cryomodule with a top-loading cold mass. The hermetic unit consists of a niobium cavity which operating at 1.3GHz and connected with two symmetrically opposed couplers which can deliver 100kW RF power to the beam. Liquid helium supplied at 4.4 K is converted to superfluid helium-II through a cryogenic insert on board which includes 4 K phase separator, 4K/2K heat exchanger and Joule-Thompson valve. In 2016, the VECC ICM has been tested at TRIUMF and demonstrated 10.5 MeV acceleration. A summary of the VECC ICM commissioning are presented.

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MOPB043

Pansophy, a JLab SRF Engineering Data Management System, Supporting Data Collection, Retrieval and Analysis Utilized by LCLS-II

148

V.D. Bookwalter, M. Dickey, E.A. McEwen, M.G. Salvador
JLab, Newport News, Virginia, USA

Pansophy is an Engineering Data Management System that provides a comprehensive solution for managing information in the production and testing of cryomodules. It is especially suited to supporting the Data & Quality Management Systems for large projects like LCLS-II. With extensive amounts of data collected for an individual project, data retrieval to facilitate feedback and enhancement of production and processing activities is a high priority. The priority shares importance with the needs of managing the project, including production status, NCR, and Quality Management reports. Recent Pansophy enhancements have been to Data and Quality management reports and statistical analysis. Such enhancements include a database driven menu system, extended MSWord macro and preprocessing of travelers, and an extensive reporting system. The reporting system allows managers and group leaders to quickly respond to the needs of the project in areas of cavity and cryomodule production, data collection, NCR, Quality Management and schedule. Extensions include integration with the SRF inventory system PRIMeS, allowing traceability from receiving of manufactured parts to final cryomodule product.

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MOPB044

Magnetic Hygiene Control on LCLS-II Cryomodules Fabricated at JLab

153

G. Cheng, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, R.A. Legg, H. Park, K.M. Wilson, L. Zhao
JLab, Newport News, Virginia, USA

Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and the LCLS-II project.
Jefferson Lab (JLab) is in collaboration with Fermi Na-tional Accelerator Laboratory (Fermilab) to build 18 cryomodules to install at the SLAC National Accelerator Laboratory's tunnel as part of the Linac Coherent Light Source upgrade project (LCLS-II). Each LCLS-II cry-omodule hosts 8 superconducting niobium cavities that adopt the nitrogen doping technique, which aims to en-hance the cavity quality factor Qo to reduce the consumption of liquid helium used to cool down the cavities. It is known that the Qo of niobium cavities is affected by cavity surface magnetic field. Traditionally, magnetic shields made of high magnetic permeability mu-metals are employed as a passive shielding of the ambient magnetic fluxes. During the LCLS-II cryomodule development, magnetic hygiene control that includes magnetic shielding and demagnetization of parts and the whole-machine is implemented. JLab and Fermilab worked closely on developing magnetic hygiene control procedures, identifying relevant tools, investigating causes of magnetization, magnetic field monitoring, etc. This paper focuses on JLab's experiences with LCLS-II cryomodule magnetic hygiene control during its fabrication.
Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.

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MOPB045

JLab New Injector Cryomodule Design, Fabrication and Testing

158

G. Cheng, M.A. Drury, J.F. Fischer, R. Kazimi, K. Macha, H. Wang
JLab, Newport News, Virginia, USA

Funding: U.S. DOE Contract No. DE-AC05-06OR23177.
A new Injector Cryomodule (INJ CM) aimed to replace the existing Quarter Cryomodule in the CEBAF tunnel has been developed at Jefferson Lab (JLab). It is sched-uled to be first tested in the Cryomodule Test Facility (CMTF) for module performance then the Upgraded Injector Test Facility (UITF) with electron beam. This new cryomodule, hosting a 2-cell and 7-cell cavity, is designed to boost the electron energy from 200 keV to 5 MeV and permit 380 uA - 1.0 mA of beam current. The 2-cell cavity is a new design whereas the 7-cell cavity is refurbished from a low loss cavity from the retired JLab Renascence Cryomodule. The INJ CM adopts quite a few designs from the JLab 12 GeV Upgrade Cryomodule (C100). Examples of this include having the cold mass hung from a spaceframe structure by use of axial and transverse Nitronic rods, cavities to be tuned by scissor-jack style tuners and the end cans are actually modified from C100 style end cans. However, this new INJ CM is not a quarter of the C100 Cryomodule. This paper focuses on the major design features, fabrication and alignment process and testing of the module and its components.
Authored by Jefferson Science Associates, LLC. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for Government purposes.

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MOPB046

LCLS-II Cryomodule Production at JLab

163

R.A. Legg, G. Cheng, E. Daly, G.K. Davis, M.A. Drury, J.F. Fischer, T. Hiatt, N.A. Huque, L.K. King, J.P. Preble, A.V. Reilly, M. Stirbet, K.M. Wilson
JLab, Newport News, Virginia, USA

Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515.
The LCLS-II cryomodule construction program leverages the mature XFEL cryomodule design to produce technologically sophisticated cryomodules with a minimum of R&D according to an accelerated manufacturing schedule. Jlab, as one of the partner labs, is producing 18 cryomodules for LCLS-II. To meet the quality and schedule demands of LCLS-II, many upgrades to the JLAB cryomodule assembly infrastructure and techniques have been made. JLab has installed a new cleanroom for string assembly and instituted new protocols to minimize particulate transfer into the cavities during the cryomodule construction process. JLab has also instituted a set of magnetic hygiene protocols to be used during the assembly process to minimize magnetic field impingement on the finished cavity structure. The goal has been to have gradients, both maximum and field emission onset, that do not degrade between the cavity vertical test and final cryomodule qualification, while maximizing the Q0 of each finished cavity. Results from the prototype cryomodule assembly are presented.

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MOPB049

Upgraded Cavities for the CEBAF Cryomodule Rework Program

168

R.A. Rimmer, G. Cheng, G. Ciovati, W.A. Clemens, E. Daly, G.K. Davis, J. Follkie, D. Forehand, F. Fors, J. Guo, J. Henry, K. Macha, F. Marhauser, G.R. Myneni, L. Turlington
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The CEBAF cryomodule rework program has been a successful tool to recover and maintain the energy reach of the original baseline 6 GeV accelerator. The weakest original modules with eight five-cell cavities assembled in four 'pairs', with a specification when new of 20 MV per cryomodule (5 MV/m), are disassembled, re-cleaned with modern techniques and re-qualified to at least 50 MV (12.5 MV/m), (leading to the acronym 'C50'). The cost per recovered MV is much less than building new modules. However over time the stock of weak modules is being used up and the voltage gain per rework cycle is diminishing. In an attempt to increase the gain per cycle it is proposed to rework the cavities by replacing the original accelerating cells with new ones of an improved shape and better material. The original CEBAF HOM and FPC end groups are retained. The goal is to achieve up to 75 MV (18.75 MV/m) for the reworked module ('C75'). We report on the fabrication experience and test results of the first trial pair, containing two such reworked cavities.

Poster MOPB049 [1.503 MB]

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MOPB050

Cavity Processing and Testing Activities at Jefferson Lab for LCLS-II Production

173

L. Zhao, G.K. Davis, J. Follkie, D. Forehand, K. Macha, A.D. Palczewski, A.V. Reilly
JLab, Newport News, Virginia, USA

Funding: Work supported by Jefferson Science Associates, LLC under U.S. DOE Contracts DE-AC05-06OR23177 and DE-AC02-76SF00515 for the LCLS-II Project.
Cryomodule production for LCLS-II is well underway at Jefferson Lab. This paper explains the process flow for production cavities, from being received at the Test Lab to being assembled onto cavity strings. Taking our facility and infrastructure into consideration, process optimization and process control are implemented to ensure high quality products.

Poster MOPB050 [2.338 MB]

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MOPB052

Dual-ridge Waveguide Load Design for eRHIC

177

P. Kolb, Y. Gao, C. Pai, R. Porqueddu, K.S. Smith, W. Xu
BNL, Upton, Long Island, New York, USA
Y. Gao
PKU, Beijing, People's Republic of China

Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
To increase the real estate gradient in the eRHIC electron accelerator waveguide HOM couplers are being considered. These significantly reduce the length of individual cavities and address inter-cavity trapped modes, allowing for an increased number of cavities per cryomodule, which would increase the real estate gradient. The choice of waveguide went to a dual ridge waveguide due to a smaller size compared to rectangular waveguides. The waveguide termination, to convert the RF energy into thermal energy, is a custom designed load based on a silicon carbide dielectric that is already being used in beamline absorbers. Simulations of the RF properties of the load are presented as well as first measurements on a prototype.

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MOPB053

RF Energy Harvesting of HOM Power

180

C. Xu, I. Ben-Zvi, Q. Wupresenter, T. Xin
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

In an accelerator cavity, Higher Order Modes (HOM) are generated by the current of the beam. The HOM power can reach tens of kilowatts in a high current accelerator, depending on the details of the beam and cavity design. In this report, we propose a novel RF harvesting system to recover the HOM power into DC power which can further used for various purposes such as driving a solid state or klystron RF amplifier to supply fundamental RF power at other frequencies, charge batteries etc. The efficiency would be a product of the energy recovery and regeneration efficiencies, where the state of art is 90%. The proposed HOM power recycling system contains a multiple band harmonic RF coupler, broadband RF antenna system, a high power rectifier diode circuit and a DC load.
1) Collider-Accelerator Department, Brookhaven National Lab, Upton, NY 11973, USA 2) Physics & Astronomy Department, Stony Brook University, Stony Brook, NY 11794, USA

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MOPB054

Design of Fundamental Power Coupler for High Intensity Heavy-ion Accelerator

183

B. Bing, T.M. Huang, Q. Ma, F. Meng, W.M. Pan
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

A single-window coaxial coupler at warm has been designed for high intensity heavy-ion accelerator. The coupler is designed to handle 100 kW CW power of 325 MHz and is currently being fabricated. T-bend transition and doorknob have been taken into account. The length of the T-bend short circuit is sensitive to S parameters and contributes to the online adjustment of VSWR in RF conditioning. The doorknob type is adopted to realize the transition from a half-height WR 2300 waveguide to a coaxial line ended with a coupling antenna. This paper describes the RF design, thermal stress and heat load analysis of the coupler as well as multipacting simula-tions.

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MOPB061

Quality Control of Copper Plating in STF-2 Input Power Couplers

186

E. Kako, R. Ueki
KEK, Ibaraki, Japan
K. Hiroaki, J. Taguchi
Nomura Plating Co, Ltd., Osaka, Japan
K. Okihira, K. Sennyu
MHI, Hiroshima, Japan
F. Saito, H. Umezawa
Tokyo Denkai Co., Ltd., Tokyo, Japan
O. Yushiro
Toshiba Electron Tubes & Devices Co., Ltd, Tokyo, Japan

Purity of thin copper plating using in input power couplers for superconducting cavities is one of important characteristics for considering thermal losses at low temperature. Various samples of thin copper plating on stainless sheets was fabricated by three companies with their own plating techniques. The RRR values of the samples with different thickness of copper plating were compared in the condition before and after heat treatment at 800oC in a brazing furnace. Deterioration of the RRR was observed in all of samples after heat treatment. The results of the RRR measurements and sample analysis of impurities will be reported in this paper.

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MOPB062

Development of HOM Absorbers for CW Superconducting Cavities in Energy Recovery Linac

191

T. Ota, A. Miyamoto, K. Sato, M. Takasaki, M. Yamada
Toshiba, Yokohama, Japan
E. Kakopresenter, T. Konomi, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Higher Order Modes (HOM) absorbers for superconducting cavities have been developing at TOSHIBA in collaboration with High Energy Accelerator Research Organization (KEK) since 2015. Prototype HOM absorbers for 1.3 GHz 9-cell superconducting cavity were fabricated. An AlN lossy dielectrics cylinder was brazed with a copper cylinder, and the cool-down tests by nitrogen gas was carried out. Copper cylinders and SUS flanges were joined by electron beam welding to fabricate a whole prototype HOM absorber. Fabrication process of the prototype HOM absorber will be presented in this paper.

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MOPB063

Fundamental Studies for the STF-type Power Coupler for ILC

194

Y. Yamamoto, E. Kako, T. Matsumoto, S. Michizono, A. Yamamoto
KEK, Ibaraki, Japan
M. Irikura, M. Ishibashi, H. Yasutake
Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi, Japan

From the view point of mass-production for the power coupler in ILC, the fundamental studies for the STF-type power coupler are under progress by the collaboration between KEK and TETD. At present, there are various rinsing procedures for power coupler in the world-wide laboratories. In this R&D, the main topic is to investigate the various rinsing effects in the copper plating and the ceramic through the high power test. In this paper, the first results will be presented.

Poster MOPB063 [2.237 MB]

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MOPB064

High Power Test for Plug-compatible STF-type Power Coupler for ILC

199

Y. Yamamoto, E. Kako, T. Matsumoto, S. Michizono, A. Yamamoto
KEK, Ibaraki, Japan
C. Julie, E. Montesinos
CERN, Geneva, Switzerland

From the view point of plug-compatibility for the power coupler in the ILC, recommended by Linear Collider Collaboration in 2013, new STF-type power couplers with 40mm of input port diameter were re-designed, fabricated and successfully high-power-tested. Moreover, from the view point of the cost reduction for the ILC, another type of power couplers with TiN coating-free ceramic were also fabricated and high-power-tested by the collaboration between CERN and KEK. In this paper, the detailed results for the both power couplers will be presented.

Poster MOPB064 [6.671 MB]

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MOPB065

Development of Hybrid Superconducting Photocathodes on Niobium Using High QE Coatings

205

M. Warren, A.R. Denchfield, N. Samuelson, J. Zasadzinski
IIT, Chicago, Illinois, USA
W. Gai, J.H. Shao, E.E. Wisniewski
ANL, Argonne, Illinois, USA
L.K. Spentzouris, Z.M. Yusof
Illinois Institute of Technology, Chicago, Illinois, USA

High power, low emittance electron beams require superconducting RF photoinjectors, typically made of pure Nb, and a superconducting photocathode is desired. However, superconductivity and high photocathode quantum efficiency (QE) are not compatible, e.g. QE for pure Nb is only 10^-5 at 260 nm wavelength. Here is presented the current status of the development of hybrid superconducting photocathodes by the deposition of thin films of a high QE metal or semiconductor on Nb. Nb plugs coated with 10-100 nm of Mg have been tested for adhesion and dark current under RF fields as high as 60MV/m. QE measurements show significant enhancements over Nb. In another test, ultra thin films of the high QE material Cs2Te deposited on Nb are reported. Using the standard deposition procedure, QE ~12% is found for films ~ 200Å. As the thickness is reduced QE maintains a high value ~ 6% for films as thin as 2.0 nm. These results are quite promising for future superconducting photocathodes.

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MOPB066

Development of 81.25 MHz 20 kW SSPA for RAON Accelerator

210

C.O. Choi, H. Jang, H.C. Jung, D.Y. Lee, K.T. Son
IBS, Daejeon, Republic of Korea

A heavy ion accelerator, RAON is under development in Daejeon, Korea by Rare Isotope Science Project (RISP). In this accelerator, 81.25 MHz Radio Frequency Quadrupole (RFQ) will be used for the acceleration of various ions from several tens of keV/u to about half MeV/u. For this system two 80 kW RF power sources are planned and RISP will develop them with a solid state power amplifier (SSPA) architecture. As a first step, a 20 kW SSPA was developed and its performance was tested. In this presentation the current status of developed SSPA and its test results will be presented

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MOPB068

Development of 4-way 81.25 MHz 20 kW High Power Combiner Using Parallel Plate Structure

213

K.T. Son, C.O. Choi, H. Jang, H.C. Jung, D.Y. Lee
IBS, Daejeon, Republic of Korea

The recent development of semiconductor technology has proved that solid-state RF amplifier is a quite effective alternative high power RF source for numerous accelerator applications. To develop a high power SSPA system, high power combiner is required to combine the RF power from a lot of solid-state RF module. The parallel plate RF power combiner, which is designed to combine various high power modules, is developed for RAON(Rare the rare isotope accelerator complex for on-line experiment). In this presentation, the status of developed 81.25 MHz 20 kW power combiner will be described.

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MOPB069

Design of the High Power Input Coupler for CEPC Main Ring Cavity *

216

T.M. Huang, Q. Ma, J.Y. Zhai
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The main ring cavities of CEPC project are two-cell el-liptical superconducting cavities operating at 650 MHz in CW mode. Each cavity equips with one high power input coupler and each coupler has to deliver at least 300 kW of CW RF power to the beam. A variable coupling from 10⁵ to 2·10⁶ is required to meet different operation modes. Considering the cavities working with high quali-ty factor up to 2·10¹⁰, the coupler assembled with cavity in class 10 clean room is strongly recommended to protect the cavity from contamination. Also, low cryogenic heat loss is one of the important issues for a large scale CW operation machine. Some of the above requirements should be compromise. Therefore, it's a big challenge to design a high power input coupler fulfilling the above requirements simultaneously. A new coupler that employs 75 Ω coaxial line sections, a planar ceramic disk win-dow, a coaxial to waveguide transition and a coupling adjusting actuator has been designed. In this paper, the RF design, thermal stress analysis and preliminary me-chanical design of the coupler are presented.

Poster MOPB069 [0.735 MB]

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MOPB070

The Improvement of the Power Coupler for CADS SC Spoke Cavities

220

T.M. Huang, B. Bing, X. Chen, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, G.W. Wang
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

Twenty superconducting spoke cavities mounted in three cryomodules (CM1, CM2 and CM4) were in-stalled in the CADS, a test facility of 10 mA, 25 MeV CW proton linac. Each cavity was equipped with one coaxial type fundamental power coupler (FPC). Fatal window crack was observed during the test cryomod-ule (TCM) commissioning. A series of experiments were subsequently implemented and eventually at-tributed the window crack to the electron bombard-ment from cavity field emission (FE). Improvements covering the coupler cleaning and assembly proce-dure, the structure and position modifications were thus implemented, aiming to reduce the cavity contam-ination and avoid the window damaged by cavity FE electrons. This paper will describe how the coupler window damaged by cavity field emission and the improve-ments for cure. In addition, the performances of FPCs for CM1, CM2 and CM4 were compared.

Poster MOPB070 [0.613 MB]

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MOPB071

The Recent Research of HOM Damper for Superconducting Cavity in IHEP

223

F. Meng, T.M. Huang, H.Y. Lin, Q. Ma, W.M. Pan, J.Y. Zhai, P. Zhang, H.J. Zheng
IHEP, Beijing, People's Republic of China

Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400)
For high current accelerator, the efficient higher-order mode (HOM) damping is always an important issue. HOM damper with microwave absorbing material is a key component for high power and broadband HOM damping application. To pursue the high damping efficiency, some ideal material with good microwave absorbing capacity is essential during the RF design and fabrication phase. Sometimes the selection and test of material is the first step and also a long step. This paper will present the recent work on HOM dampers for BEPCII 500MHz cavity and CEPC 650MHz cavity in IHEP.

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MOPB072

The Development of the LLRF Control System for the New High Power Test Stand of Couplers

227

L. Chen, W. Chang, T.C. Jiang, C.L. Li, Y.M. Li, R.X. Wang, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

RF power conditioning is an effective way to suppress multipacting in fundamental mode power couplers. Room temperature test-stand conditioning is an essential step that can be hardly circumvented before couplers are installed on SC cavities. Based on our original one, a new test-stand has been designed and being assembled at IMP. It can work as a multi-task platform conditioning different couplers, including couplers for HWR010 cavities and HWR015 cavities. It is also featured with the capacity to flexibly change β according to different specifications. A variety of conditioning modes have been incorporated into the LLRF system, including frequency sweeping mode, amplitude sweeping mode, arbitrary-duty-cycle mode and triangle-wave mode. In addition, smartly-conditioning has been achieved because of the accomplishment of smart interlocks and automatic reset in the system.

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MOPB074

Analysis of Higher Order Modes of the Superconducting Cavities for the China-ADS Injector-II in IMP

231

C. Zhang, L. Chen, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, Y.M. Li, F. Pan, R.X. Wang, A.D. Wu, Q.J. Wu, W.M. Yue, S.H. Zhang, S.X. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Funding: funded by Natural Science Foundation of China， No.11505253
The influence of the higher order modes on the beam dynamics and the cryogenic losses has been studied for the superconducting section of the CIADS project in this paper. In addition, the necessity of HOM dampers in the Superconducting (SC) cavities is discussed.

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MOPB075

Quench Protection in Digital Power Supplies for Superconducting Magnets in ADS

233

J. Zhao, S. Zhang, Z.Z. Zhou
IMP/CAS, Lanzhou, People's Republic of China

The front-end demo superconducting Linac for Chinese ADS (Accelerator Driven Sub-critical System) project is under construction at institute of modern physics(IMP) in Lanzhou. It will demonstrate the key technologies and the feasibility of a high power beam for the future national project " the Chinese Initiative Accelerator Driven Subcritical System(CIADS)". In this system, there are about 60 superconducting magnets, including solenoids, vertical correction and horizontal correction. They are utilized to focus and correct the proton beam. Quench protection of the superconducting magnets is key to reliability of the facility. A full digital power supply is developed and employed as excitation source for all of these superconducting magnets. In this paper, an FPGA-based quench protection plan implemented in the power supplies is mainly described. The commissioning results show that it is feasible.

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MOPB076

Analysis of the Production, Installation and Commissioning of the European-XFEL Frequency Tuners

235

R. Paparella, A. Bosotti, D. Sertorepresenter
INFN/LASA, Segrate (MI), Italy
C. Albrecht, S. Barbanotti, A. Bellandi, J. Branlard, K. Jensch, L. Lilje
DESY, Hamburg, Germany
C. Cloué, T. Trublet
CEA/IRFU, Gif-sur-Yvette, France
C. Madec
CEA, Gif-sur-Yvette, France

In the European-XFEL superconducting linac, mechanical frequency tuners equipped with stepper motors and piezoelectric actuators provide cold tuning of each of the 768 1.3 GHz cavities. More than 820 complete tuning systems were fabricated and pre-assembled in industry, tested at several stages before and after assembly and successfully commissioned during cryo-module cold tests at AMTF (DESY). Quality control strategy adopted to preserve the well-assessed tuner reliability through such a large-scale industrial production is critically reviewed and the lessons learned are presented in this paper. The statistical analysis of the large set of data acquired up to the recent commissioning of the entire linac is then summarized.

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MOPB077

Operational Experience of the European-XFEL 3.9 GHz Coaxial Tuners

240

R. Paparella, A. Bellandi, A. Bignami, A. Bosotti, D. Sertore
INFN/LASA, Segrate (MI), Italy
C.G. Maiano
ESS, Lund, Sweden
P. Pierinipresenter
DESY, Hamburg, Germany

The European-XFEL injector hosts a third-harmonic section composed by a module with eigth 3.9 GHz cavities equipped with a coaxial frequency tuner inspired by INFN-LASA Blade Tuner design. The 3.9 GHz tuning system met specifications during all the injector runs in 2016 up to the recent commissioning of the entire linac; it matched the required tuning range and frequency sensitivity although higher than expected cavity detuning was experienced during pressure transients in the cryogenic system. An analysis of all collected experimental data is reported in this paper together with the strategy developed to provide a sound and effective retuning routine to the control room operator.

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MOPB078

Power Coupler Design for the LUCRECE Project

245

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

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

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MOPB079

HOM Coupler Alterations for the LHC DQW Crab Cavity

249

J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
G. Burt, N.C. Shipman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga
CERN, Geneva, Switzerland
S. Verdú-Andrés, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA

As part of the High Luminosity Large Hadron Collider (HL-LHC) project, 16 crab cavities are to be installed in the LHC in 2025. The two crab cavity designs are the Double Quarter Wave (DQW) and Radio Frequency Dipole (RFD). Preliminary beam tests in the Super Proton Synchrotron (SPS) are planned for both cavity types, with the DQW scheduled for testing in 2018. In reference to to Higher Order Mode (HOM) damping, the DQW has three identical on-cell HOM couplers. These HOM couplers provide a band-stop response at the frequency of the fundamental mode and act as a transmission path for the cavity HOMs. For the SPS cavity design, several geometric constraints exist. These give rise to dimensional limitations which in-turn impose limitations on the RF performance of the HOM couplers. As such, for the LHC assembly, the HOM coupler design is re-visited to take into account the relaxed geometric limitations, hence allowing the feasibility of an increased RF performance to be investigated. In addition to the RF performance, several geometric alterations were incorporated to ease manufacturing processes, tolerances and costs.

Poster MOPB079 [2.038 MB]

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MOPB080

The Stable Operation of MPG and Measurement of Output

254

B.T. Li, X.Y. Lu, L. Xiao, D.Y. Yang, Y. Yang, Z.Q. Yang, J. Zhao
PKU, Beijing, People's Republic of China

The concept of micro-pulse electron gun(MPG) was proposed decades ago. It can provide electron beam with high current, short pulse and low emittance. But it is still not put into practical use as electron source because of its unsteady operating state. This paper presents an experimental result of the steady running of MPG which can operate stably for more than ten hours. The energy spread of the electron beam is also measured, the peak is located at near 20eV and half width is less than 15eV .

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MOPB082

A Preliminary Scheme for X-ray Emission Based on Micro-pulse Electron Gun

259

Y. Yang, B.T. Li, X.Y. Lu, W.W. Tan, L. Xiao, D.Y. Yang, Z.Q. Yang, J. Zhao
PKU, Beijing, People's Republic of China

X-ray is now widely used in many areas of physics, biology, chemistry and materials. And how to achieve emission, monochrome, and focusing of x-ray is of great significance to study. Micro-pulse electron gun (MPG) is a new type of electron source, with characteristics of high repetition frequency, short-pulse and low cost. Generating x-ray with better monochromaticity is one of the potential applications of MPG. And a preliminary scheme of X-ray based on MPG is proposed in this paper. The scheme is designed by comparing different anode materials and the thickness of filters. The simulation results based on the software MCNP5 show that the proposed scheme can effectively improve the monotonicity of the generated X-rays.

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MOPB086

First Results of the IFMIF/EVEDA-SaTHoRI Tests

262

O. Piquet, N. Bazinpresenter, P. Carbonnier, J.K. Chambrillon, M. Desmons, G. Devanz, H. Jenhani, C. Servouin
CEA/DRF/IRFU, Gif-sur-Yvette, France
P. Cara
Fusion for Energy, Garching, Germany
J.F. Denis, L. Maurice, J. Relland
CEA/IRFU, Gif-sur-Yvette, France
F. Éozénou, P. Hardy, E. Jacques, Y. Lussignol, P. Sahuquet
CEA/DSM/IRFU, France
D. Gex, A. Jokinen, G. Phillips
F4E, Germany
I. Moya, P. Méndez
CIEMAT, Madrid, Spain

The SaTHoRI test stand (Satellite de Tests Horizontal des Résonateurs IFMIF) aims to characterize a jacketed and fully dressed cavity with its coupler and tuner. A dedicated test cryostat has been manufactured and is connected to an existing horizontal test cryostat which provides the cryogenic coolant. A RF source ' provided by the IFMIF collaboration, one of the four RF sources which will be used for the cryomodule at Rokkasho ' has been installed and commissioned at CEA. This paper describes the test stand and presents the first results.

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MOPB087

Frequency Tuner Development and Testing at Cornell for the RAON Half-wave-resonator

266

M. Ge, F. Furuta, J.E. Gillette, T. Gruber, S.W. Hartman, M. Liepe, T.I. O'Connell, P.J. Pamel, P. Quigley, J. Sears, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
B.H. Choi, J. Joo, J.W. Kim, W.K. Kim, J. Lee, I. Shin
IBS, Daejeon, Republic of Korea

The half-wave-resonators (HWRs) for the RAON project require a slow frequency tuner that can provide >80 kHz tuning range. Cornell University is currently in the process of designing, prototyping, and testing this HWR tuner. In this paper, we present the optimized tuner design, prototype fabrication, test insert preparation, and cryogenic test results. The performance of the tuner is analysed in detail.

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MOPB088

Experience on In-situ Module Repair and Set Up of Non XFEL Cavity Strings at DESY

269

M. Schmökel, A. Daniel, N. Krupka, A. Matheisen, S. Saegebarth, M. Schalwat, P. Schilling
DESY, Hamburg, Germany

All components installed to the European XFEL cavity string modules underwent an intensive inspection and quality control before acceptance for installation to cavities or modules. Even though some RF feed throughs for HOM coupler- and Pick Up antennas showed leaks at the ceramic insulation after module test at 2 K. Due to time restriction and continuity of production the exchange of these parts needed to be done without reentering the cleanroom. Successful repair of these modules took place by setting up a local cleanroom onto the cavity string. In collaboration with Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a cavity string for the ELBE project was assembled at DESY and transported to HZDR for installation to the vacuum vessel. A spare module with 3.9 GHz Resonators for the European XFEL was set up at DESY and will be tested and qualified for the European XFEL. Due to delay in delivery of the power couplers, four power couplers were installed after string assembly.

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MOPB089

Characterisation of Magnetic Shielding Material for HL-LHC Crab Cavities

273

K. Eiler, P. Arpaia, M.C.L. Buzio, O. Capatina, S.A.E. Langeslag, A. Parrella
CERN, Geneva, Switzerland
P. Arpaia, A. Parrella
Naples University Federico II, Science and Technology Pole, Napoli, Italy
A. Parrella
IT, Lisboa, Portugal
N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Funding: CERN, 1211 Geneva 23
To guarantee optimum performance, the crab cavities for the high-luminosity upgrade of CERN's LHC need to be shielded from external magnetic fields. Consequently, they will be enclosed by two layers of magnetic shielding, of which the inner is immersed in superfluid helium at 2 K. A Ni-based high-permeability material with a tailored composition and a designated heat treatment is applied. Its magnetic properties at cryogenic temperature are however not yet fully assessed. Especially the effect of deformation on magnetic properties has not been thoroughly investigated, however strain effects may have severe consequences. A magnetic measurement set-up has been developed, and the magnetic permeability at room temperature and at cryogenic temperatures is evaluated, showing that the maximum relative permeability at 4 K exceeds the design criteria of 100, 000. Measurements of the magnetic permeability after introduction of uniaxial plastic deformation between 0% and 3% are conducted by means of an Epstein frame. Results show that deformation induces significant decrease of the magnetic performance, underlining that particular care must be taken during all stages of handling and operation.
*konrad.eiler@cern.ch

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MOPB090

Sub-micro-Tesla Magnetic Shielding Design for Cryomodules in the High-gradient Program at CERN

278

S. Papadopoulos, L. Dassa, F. Gerigk, F. Pillon, S. Ramberger, P. Yilmazer
CERN, Geneva, Switzerland
J. Dequaire
Intitek, Lyon, France

In the framework of the High-Gradient R\&D program at CERN a cryomodule, consisting of four superconducting 5-cell cavities, has been designed. In order to reduce flux trapping in the surface of the superconductor and to minimize Q degradation during a quench, highly effective magnetic shielding is needed. The solution proposed includes cold and warm passive shielding enhanced by four compensating coils. In this paper the magneto-static simulation results are presented illustrating different design considerations that led to a final design. Finally the shielding ability of the vacuum vessel is investigated experimentally through ambient magnetic field measurements.

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MOPB094

Commissioning of Demonstrator Module for CW Heavy Ion LINAC@GSI

283

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

The cw - Linac - demonstrator is a prototype of the first section of the proposed cw-LINAC@GSI, comprising a superconducting CH-cavity embedded by two superconducting solenoids. The sc CH-structure is the key component and offers a variety of research and development. The beam focusing solenoids provide maximum fields of 9.3 T at an overall length of 380 mm and a free beam aperture of 30 mm. The magnetic induction at the fringe is minimized to 50 mT at the inner NbTi-surface of the neighboring cavity. The fabrication of the key components is finished, as well as the cold performance testing of the RF cavity. The cryostat is ready for assembling and the test environment is completely prepared. After successful testing of the RF-Power coupler, the components will be assembled to the suspended frame under cleanroom conditions. Alignment, assembly, under cleanroom condition issues will be presented.

Poster MOPB094 [2.881 MB]

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MOPB096

Estimation of Alignment Error by Measuring Higher-order-mode of Injector Superconducting Cavity at KEK-cERL

286

Y. Honda, E. Kako, T. Konomi, T. Miyajima, T. Obina, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Precise alignment of accelerator cavities is important in realizing a low emittance beam. Especially in the cases of superconducting cavities installed in a cryomodule, it is difficult to mechanically measure the position of the cavities. By measuring higher-order-modes (HOM) excited by a beam, the electrical center of the cavities can be estimated. We have developed a HOM measurement system for the injector superconducting accelerator cavities of KEK ERL test accelerator (cERL).Comparing the HOM signals of the three independent cavities in the cryomodule, we estimated the relative positioning errors of the three cavities.

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MOPB097

Degradation and Recovery of Cavity Performances in Compact-ERL Injector Cryomodule

289

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

Injector cryomodule for cERL consists of three 2-cell cavities equipped with double-feeds input couplers, five antenna-type HOM couplers and a slide-jack tuner with two piezo actuators. After cryomodule assembly and first cool-down tests in 2012, the cERL injector cryomodule has been stably operated with beam for four years. Gradual increases of x-ray radiation levels due to field emission were observed during long term beam operation. High power pulsed RF conditioning as a cure method was applied in the cool-down period in 2016 and 2017, so that degraded cavity performances have almost recovered up to the original levels. Performance recovery status in three 2-cell cavities will be reported in this paper.

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MOPB099

Design of C-ADS Injector-I Cryomodule for 325MHz Cavities

294

R. Ge, L. Bian, R. Han, S.P. Li, M.J. Sang, L.R. Sun, M.F. Xu, R. Ye, J.Q. Zhang, J.H. Zhang, X.Z. Zhang
IHEP, Beijing, People's Republic of China

Funding: Supported by Strategic Priority Research Program of CAS (XDA030213)
The Chinese Accelerator Driven Sub-critical system (C-ADS) uses a high energy proton beam to bombard the metal target and generate neutrons to deal with the nuclear waste. The Chinese ADS proton linear has two 0~10 MeV injectors and one 10~1500 MeV superconducting linac. Injector-I is studied by the Institute of High Energy Physics (IHEP) under construction in the Beijing, China. The linear accelerator consists of two accelerating cryomodules operating at the temperature of 2 Kelvin. This paper describes the structure and thermal performances analysis of the cryomodule. The analysis takes into account all the main contributors (support posts, multilayer insulation, current leads, power couplers, and cavities) to the static and dynamic heat load at various cryogenic temperature levels. The thermal simulation analysis of the cryomodule is important theory foundation of optimization and commissioning.

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MOPB101

Cryomodule Fabrication and Modification for High Current Operation at the Mainz Energy Recovering Superconducting Accelerator MESA

297

T. Stengler, K. Aulenbacher, F. Hug, D. Simon
IKP, Mainz, Germany
K. Aulenbacher, T. Kürzeder
HIM, Mainz, Germany

Funding: This work is supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA" EXC 1098/2014}
At Johannes Gutenberg-Universität Mainz, the Institute for Nuclear Physics is currently building the multiturn ERL 'Mainz Energy-Recovering Superconducting Accelerator' MESA. The §I{1.3}{\giga\hertz} cryomodules are based on the ELBE modules at Helmholtz Center Dresden-Rossendorf (HZDR) but are modified to suit the high current, energy recovering purposes of MESA. With two 9-cell TESLA cavities each, they shall provide §I{50}{\mega\electronvolt} energy gain per turn. The design and fabrication was done by Research Instruments GmbH, Bergisch Gladbach, Germany. The current status of the cryomodules, the test set up at the Helmholtz-Institute Mainz, the cavity properties and their tests will be discussed.

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MOPB102

Preliminary Design on the Cryomodule of the HWR for the Secondary Particle Generation at KOMAC

301

H.-J. Kwon, Y.-S. Cho, J.J. Dang, H.S. Kim, K.H. Kim, S. Lee, Y.G. Song
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea

Funding: This work has been supported through KOMAC (Korea of Multi-purpose Accelerator Complex) operation fund of KAERI by MSIP (Ministry of Science, ICT and Future Planning).
A 100 MeV proton linac based on the radio frequency quadrupole and conventional drift tube linac has been operating for user service at KOMAC (Korea Multi-purpose Accelerator Complex). A superconducting linac based on the half-wave resonator is studied in order to increase the proton energy from 100 MeV to 160 MeV for secondary particle generation such as neutron. A cryomodule and its cryogenics were designed. The operating temperature of the HWR is 2 K. One cryomodule contains four HWR cavities and it didn't have superconducting solenoid because a doublet lattice using normal conducting magnet was considered as focusing elements. A thermal design was conducted and the structure was designed based on the existing well proven technologies. The results of the design on the cryomodule and cryogenics for KOMAC HWR are summarized and discussed in the conference.

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MOPB104

Development of a Novel Supporting System for High Luminosity LHC SRF Crab Cavities

304

T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
K. Artoos, R. Calaga, O. Capatina, T. Capelli, M. Sosin, J.S. Swieszek, C. Zanoni
CERN, Geneva, Switzerland
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.J. Jones
Lancaster University, Lancaster, United Kingdom

Compact SRF Crab Cavities are integral to the HL-LHC upgrade. This paper details the design of support structures within the SPS (Super Proton Synchrotron) Crab Cavity Cryomodule. For ease of alignment each cavity is supported with the mechanical tuner and RF Fundamental Power Coupler (FPC) via a common support plate. To reduce heat leak and remove bellows in the FPC it was determined that this would be the fixed support for the cavity (V. Parma, 2013). In addition, novel flexural blades were designed to give increased stiffness yet allow for thermal contraction of the cavity towards the fixed point of the FPC. This approach was superior when compared via simulation to several alternative techniques. A detailed simulation model was used for optimisation of directional stiffness, identification of vibration modes and minimising thermal stresses. A transmission matrix was developed in MS Excel to assess modal deflection for given ground vibration conditions. The spreadsheet gives an instantaneous yet comparable result to time consuming random vibration FE Analyses. The final engineering design of the supporting system is now complete and will also be described in this paper.
References
V. Parma, R. B. (2013). Status of the Superconducting Proton Linac (SPL) Cryomodule. SRF2013.

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MOPB105

Thermosiphon Cooling Loops for ARIEL Cryomodules

309

Y. Ma, A.N. Koveshnikov, D. Lang, R.E. Laxdal, N. Muller
TRIUMF, Vancouver, Canada

Thermosiphon cooling loops have been used in ARIEL[1,2] cryomodules for 1.3GHz superconducting cavities cooling. It can deliver 4K liquid Helium from 4K phase separator to cavity thermal intercepts and return the vaporized liquid to the 4K phase separator as a refrigerator load. The design and test results are presented in this paper.

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MOPB106

Test Results of the European XFEL Serial-production Accelerator Modules

312

K. Kasprzak, M. Wiencek, A. Zwozniak
IFJ-PAN, Kraków, Poland
D. Kostin, D. Reschke, N. Walker
DESY, Hamburg, Germany

The serial-production tests of 100 cryomodules for the European XFEL have been finished. In this paper the statistics of the cold RF measurements in the AMTF (Accelerator Module Test Facility) are reported for all the modules. In addition comparison between the cavity vertical test results and module test results are presented.

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MOPB109

LCLS-II Cryomodule Transport System Testing

317

N.A. Huque, E. Daly
JLab, Newport News, Virginia, USA
M.W. McGee
Fermilab, Batavia, Illinois, USA

The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.

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MOPB110

Results of Accelerated Life Testing of LCLS-II Cavity Tuner Motor

323

N.A. Huque, E. Daly
JLab, Newport News, Virginia, USA
Y.M. Pischalnikov
Fermilab, Batavia, Illinois, USA

An Accelerated Life Test (ALT) of the Phytron stepper motor used in the LCLS-II cavity tuner has been conducted at JLab. Since the motor will reside inside the cryomodule, any failure would lead to a very costly and arduous repair. As such, the motor was tested for the equivalent of 30 lifetimes before being approved for use in the production cryomodules. The 9-cell LCLS-II cavity is simulated by disc springs with an equivalent spring constant. Plots of the motor position vs. tuner position ' measured via an installed linear variable differential transformer (LVDT) ' are used to measure motor motion. The titanium spindle was inspected for loss of lubrication. The motor passed the ALT, and is set to be installed in the LCLS-II cryomodules.

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MOPB111

European XFEL Linac RF System Conditioning and Operating Test

328

D. Kostin, J. Branlard, A. Gössel, O. Hensler, M. Omet, D. Reschke, A.A. Sulimov, N. Walker, M. Wiencek
DESY, Hamburg, Germany

96 accelerating modules with 768 TESLA/European-XFEL type superconducting cavities were installed in the European XFEL LINAC tunnel (XTL) in the fall 2016. Warm conditioning of the RF system - High/Low Level RF System and main input couplers - begun even before finishing the accelerator installation works. All modules were conditioned and tested prior to the installation in the tunnel in the AMTF test stand at DESY. Nevertheless, due to some repair activities on warm input coupler parts, warm conditioning was needed on a few modules/couplers. Cooling down to 2K begun in December 2016 and was finished in January 2017. Since then cold conditioning and tests are running. Several cavities in a few modules did show the multipacting (MP) effects, mostly because a cavity vacuum was filled with a dry nitrogen for before mentioned repairs on couplers in some modules. Said MP effects were seen in AMTF as well. All MP effects were successfully conditioned until now. The warm/cold RF system conditioning and its results/experiences/limits are described and discussed.

Poster MOPB111 [1.267 MB]

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