SRF2017 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOXA04	Superconducting Accelerator for ERL Based FEL EUV Light Source at KEK	ion, cavity, HOM, linac	13
	H. Sakai, E. Kako, T. Konomi, T. Kubo, K. Umemori KEK, Ibaraki, Japan T. Ota Toshiba, Yokohama, Japan M. Sawamura QST, Tokai, Japan
	An energy recovery linac (ERL)-based free electron laser (FEL) is a possible candidate of a tens of kW EUV source and open the era for next generation EUV-lithography. We have designed the 10 mA class ERL-based EUV-FEL source to generate more than 10 kW power. One of the key technologies is CW superconducting cavities to realize the energy recovery of high beam current of more than 10 mA by suppressing HOMs and high gradient acceleration of higher than 12 MV/m. This CW superconducting cavity had been developed through the construction of the Compact ERL facility in KEK and it successfully achieved the energy recovery of 1 mA CW beam until now. In this talk, first we express our design strategies of SRF cavities of the main linac of ERL-EUV light sources not only to suppress the HOMs but also to overcome the field emission problem by modifying the main linac cavity of Compact ERL more sophisticatedly. Next we show the recent development works for ERL-EUV superconducting cavity about HOM damper, cryomodule, and its clean string-assembly work by using horizontal test stand.
	Slides MOXA04 [5.938 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOXA04
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MOXA07	Development of the C-ADS SRF Accelerator at IHEP	ion, cavity, linac, cryomodule	19
	F. Yan, L. Bian, J.S. Cao, Y. Chen, Y.L. Chi, J.P. Dai, L. Dong, L.L. Dong, Y.Y. Du, H.F.S. Feisi, Y. Gao, R. Ge, H. Geng, D.Z. Guo, D.Y. He, J. He, T.M. Huang, X. Jing, B. Li, H. Li, L. Li, S.P. Li, H.Y. Lin, F. Liu, R.L. Liu, F. Long, Y.H. Lu, H.Z. Ma, Q. Ma, X. Ma, C. Meng, Z.H. Mi, H.F. Ouyang, W.M. Pan, S. Pei, Q.L. Peng, X.H. Peng, P. Sha, H. Shi, P. Su, Y.F. Sui, L.R. Sun, X.T. Sun, G.W. Wang, J.L. Wang, S.C. Wang, G. Wu, O. Xiao, X.C. Yang, Q. Ye, R. Ye, L. Yu, X.Y. Zhang, X.Y. Zhao, Y.L. Zhao, Y. Zhao, Z.H. ZhenHua, N. Zhou, Z.S. Zhou IHEP, Beijing, People's Republic of China H.Y. Zhu Institute of High Energy Physics (IHEP), People's Republic of China
	Funding: CAS Strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System) and National Natural Science Foundation of China, under contract NO. 11405190 The 10 MeV accelerator-driven subcritical system (ADS) Injector I test stand at Institute of High Energy Physics (IHEP) is a testing facility dedicated to demonstrate one of the two injector design schemes [Injector Scheme-I, which works at 325 MHz], for the ADS project in China. The ion source was installed since April of 2014, periods of commissioning are regularly scheduled between installation phases of the rest of the injector. Early this year, continuous wave (CW) proton beam has been successfully obtained with energy of 10MeV and average beam current around 2 mA, the single spoke cavities with smallest developed beta (βg=0.12) were applied and successfully commissioned. Single spoke cavities with higher beta (βg=0.21) were also adopted for the last cryomodule of 25MeV proton linac, and 170uA CW proton beam were shooting through recently. This contribution reports the details of the development of the C-ADS SRF accelerator at IHEP and the challenges of the CW machine commissioning
	Slides MOXA07 [5.605 MB]
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MOPB008	Input Power Coupler for NICA Injector Coaxial Quater Wave SC Cavity	ion, cavity, multipactoring, Windows	61
	M.V. Lalayan, T.A. Bakhareva, M. Gusarova, 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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MOPB012	Status of the IFMIF LIPAc SRF Linac	ion, cavity, cryomodule, SRF	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	ion, FEL, GUI, SRF	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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MOPB016	Operation of Diamond Superconducting RF Cavities	cavity, ion, vacuum, GUI	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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MOPB041	Status of the SOLEIL Superconducting RF System	ion, cavity, SRF, GUI	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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MOPB077	Operational Experience of the European-XFEL 3.9 GHz Coaxial Tuners	ion, cavity, FEL, MMI	240
	R. Paparella, A. Bellandi, A. Bignami, A. Bosotti, D. Sertore INFN/LASA, Segrate (MI), Italy C.G. Maiano ESS, Lund, Sweden P. Pierini 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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MOPB097	Degradation and Recovery of Cavity Performances in Compact-ERL Injector Cryomodule	ion, cavity, radiation, 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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MOPB101	Cryomodule Fabrication and Modification for High Current Operation at the Mainz Energy Recovering Superconducting Accelerator MESA	ion, cavity, cryomodule, experiment	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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MOPB106	Test Results of the European XFEL Serial-production Accelerator Modules	ion, cavity, cryomodule, FEL	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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MOPB110	Results of Accelerated Life Testing of LCLS-II Cavity Tuner Motor	ion, cavity, cryomodule, SRF	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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TUPB020	Microphonics Passive Damping	ion, cavity, SRF, simulation	423
	E.N. Zaplatin FZJ, Jülich, Germany A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Different types of external loads on the resonator walls predetermine the main working conditions of the SRF cavities. The most important of them are very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape. For pulsed operation, the Lorentz forces usually play the decisive role for the cavity design. For CW operation, the liquid helium vessel pressure instability even for 2K operations is the source of large microphonics. All deformations resulting from any type of external loads on cavity walls lead to shifts in the working RF frequency in the range of hundreds of kHz. Taking into account high Q-factor of SC cavities such a large frequency shift takes the cavity out of operation. Here we present and discuss the achievements and problems of microphonics passive damping in different type SRF cavities.
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TUPB024	Performance Tests of the Superconducting 217 MHz CH Cavity for the CW Demonstrator	ion, cavity, linac, heavy-ion	440
	F.D. Dziuba, M. Amberg, K. Aulenbacher, W.A. Barth, V. Gettmann, M. Miski-Oglu HIM, Mainz, Germany M. Amberg, M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, M. Heilmann, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia
	Regarding the future research program of super heavy element (SHE) synthesis at GSI, high intense heavy ion beams above the coulomb barrier and high average particle currents are highly demanded. The associated beam requirements exceed the capabilities of the existing Universal Linear Accelerator (UNILAC). Besides the existing GSI accelerator chain will be exclusively used as an injector for FAIR (Facility for Antiproton and Ion Research) providing high power heavy ion beams at a low repetition rate. As a consequence a new dedicated superconducting (sc) continuous wave (cw) linac is highly demanded to keep the SHE research program at GSI competitive on a high level. In this context the construction of the first linac section, which serves simultaneously as a prototype to demonstrate its reliable operability has been finished at the end of 2016. The so called demonstrator cryomodule comprises two sc 9.3 T solenoids and a sc 217 MHz crossbar-H-mode (CH) cavity with 15 equidistant accelerating gaps. Furthermore, the performance of the cavity has been successfully tested at cryogenic temperatures. The results of these tests are presented.
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TUPB060	Innovative Cryogenic Test Facility for Testing SRF Cavity Series Production	ion, cavity, SRF, cryogenics	520
	L. Bizel-Bizellot, M. Ellis, S.M. Pattalwar, M.D. Pendleton, P.A. Smith, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Testing SRF cavities in a vertical cryostat is the first step in qualifying the performance of SRF cavities before being integrated into a cryomodule. The European Spallation Source (ESS) requires 84 high-beta 5 cells, 704 MHz cavities which will be manufactured and qualified for their RF performance in a vertical cryostat at Science and Technology Facility Council (STFC) Daresbury Laboratory (United-kingdom). Taking a conventional approach each vertical test would require a large cryostat demanding more than 7000 litres of liquid helium per test for testing 3 cavities simultaneously. In order to reduce the overall operating cost, we plan to develop an alternative method to divide the liquid helium consumption by 5 by filling liquid helium only in each individual helium vessels enclosing each cavity placed horizontally in the cryostat. Therefore the test is performed in more realistic conditions such as in a cryomodule and reduces the operating time. This also reduces the mass flow-rate to be handled by a factor 10, leading to 2 g/s, thus reducing the size of the associated components such as the 2 K pumps, the safety device, the valves and transfer lines.
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TUPB064	Operating Experience on Cavity Performance of ISAC-II Superconducting Heavy Ion Linac	ion, cavity, ISAC, linac	527
	Z.Y. Yao, T. Junginger, A.N. Koveshnikov, R.E. Laxdal, Y. Ma, D.W. Storey, E. Thoeng, B.S. Waraich, V. Zvyagintsev TRIUMF, Vancouver, Canada
	ISAC-II is a superconducting heavy ion linac with 40 QWRs as an extension of ISAC facility for ISOL based on radioactive ion beam production and acceleration. Phase-I with twenty 106MHz cavities has been operating since 2006. The design spec was achieved with the completion of Phase-II with another twenty 141MHz cavities in 2010. The cavity performance statistics and operating experience have been accumulated over years. This paper will summarize the operating experience on cavity performance of ISAC-II.
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TUPB065	Design of Multi-frequency Coaxial Test Resonators	ion, cavity, niobium, SRF	531
	Z.Y. Yao, T. Junginger, R.E. Laxdal, B. Matheson, B.S. Waraich, V. Zvyagintsev TRIUMF, Vancouver, Canada
	A significant issue in low beta resonators is medium field Q-slope (MFQS) at 4K. To study the MFQS and the field dependence of surface resistance in low beta resonators, a quarter-wave resonator (QWR) and a half-wave resonator (HWR) were designed to be tested at integer harmonic frequencies of 200MHz, and up to 1.2GHz. A series of chemistry and heat treatments will be applied to these cavities so that a systemic study on the surface resistance of the coaxial resonators associating with post-processing, RF field, and frequency can be done. The detail design of these cavities and the status of cavity fabrication will be reported in this paper.
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TUPB070	INFN-LASA Cavity Design for PIP-II LB650 Cavity	cavity, ion, HOM, coupling	547
	C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy M. Bertucci, A. Bignami, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy S. Pirani ESS, Lund, Sweden
	INFN-LASA is going to join the international partnership for Fermilab PIP-II project and to provide a novel design for the 650 MHz cavity of the 0.61 beta linac section, plug compatible with the Fermilab Cryomodule design. This paper reports the cavity design features both from the electro-magnetic and mechanical aspects, with focus on the rationales at the basis of the choice of main parameters. Furthermore, the current plans for the future R&D activity are here reported, including the production of two single cells and two complete cavities.
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THYA02	Achievement of Stable Pulsed Operation at 36 MV/m in STF-2 Cryomodule at KEK	ion, cavity, cryomodule, accelerating-gradient	722
	Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori KEK, Ibaraki, Japan
	In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomdoule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities was successfully carried out. The main achievement is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification (2 of 8 cavities achieved 36 MV/m with piezo compensation), and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. In this paper, the result for the STF-2 cryomodule in three cooldown tests will be presented in detail.
	Slides THYA02 [4.042 MB]
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THYA06	Long-term Operation Experience with Beams in Compact ERL Cryomodules	ion, cavity, linac, cryomodule	736
	K. Umemori, M. Egi, K. Enami, T. Furuya, Y. Honda, E. Kako, T. Konomi, H. Sakai KEK, Ibaraki, Japan T. Okada Sokendai, Ibaraki, Japan M. Sawamura QST, Tokai, Japan
	Compact ERL (cERL) was constructed at KEK as a prototype for 3GeV ERL light source. It consists of two types of SRF cavities. Three injector 2-cell SRF cavities and two main linac 9-cell SRF cavities. The beam operation started at 2013, with 100 nA (CW). Beam current increased step by step and currently reached to 1 mA (CW). Energy recovery has successfully achieved. Performance of the SRF cavities through long term beam operation has been investigated. With the beam induced HOMs, the beam position and the beam timing were studied. cERL has suffered from heavy field emissions in operation. Field emissions of the main linac cavity started just after module assembly work, and during beam operation, performances of both the main linac and the injector SRF cavities sometimes degraded. One reason of degradation was discharges occurred at beamline components due to charge up of electrons. Pulse aging technique helped to recover SRF performances. In this presentation, details of SRF beam operation, degradation, applied recovery methods are described.
	Slides THYA06 [4.973 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THYA06
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MOXA04

Superconducting Accelerator for ERL Based FEL EUV Light Source at KEK

ion, cavity, HOM, linac

13

H. Sakai, E. Kako, T. Konomi, T. Kubo, K. Umemori
KEK, Ibaraki, Japan
T. Ota
Toshiba, Yokohama, Japan
M. Sawamura
QST, Tokai, Japan

An energy recovery linac (ERL)-based free electron laser (FEL) is a possible candidate of a tens of kW EUV source and open the era for next generation EUV-lithography. We have designed the 10 mA class ERL-based EUV-FEL source to generate more than 10 kW power. One of the key technologies is CW superconducting cavities to realize the energy recovery of high beam current of more than 10 mA by suppressing HOMs and high gradient acceleration of higher than 12 MV/m. This CW superconducting cavity had been developed through the construction of the Compact ERL facility in KEK and it successfully achieved the energy recovery of 1 mA CW beam until now. In this talk, first we express our design strategies of SRF cavities of the main linac of ERL-EUV light sources not only to suppress the HOMs but also to overcome the field emission problem by modifying the main linac cavity of Compact ERL more sophisticatedly. Next we show the recent development works for ERL-EUV superconducting cavity about HOM damper, cryomodule, and its clean string-assembly work by using horizontal test stand.

Slides MOXA04 [5.938 MB]

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MOXA07

Development of the C-ADS SRF Accelerator at IHEP

ion, cavity, linac, cryomodule

19

F. Yan, L. Bian, J.S. Cao, Y. Chen, Y.L. Chi, J.P. Dai, L. Dong, L.L. Dong, Y.Y. Du, H.F.S. Feisi, Y. Gao, R. Ge, H. Geng, D.Z. Guo, D.Y. He, J. He, T.M. Huang, X. Jing, B. Li, H. Li, L. Li, S.P. Li, H.Y. Lin, F. Liu, R.L. Liu, F. Long, Y.H. Lu, H.Z. Ma, Q. Ma, X. Ma, C. Meng, Z.H. Mi, H.F. Ouyang, W.M. Pan, S. Pei, Q.L. Peng, X.H. Peng, P. Sha, H. Shi, P. Su, Y.F. Sui, L.R. Sun, X.T. Sun, G.W. Wang, J.L. Wang, S.C. Wang, G. Wu, O. Xiao, X.C. Yang, Q. Ye, R. Ye, L. Yu, X.Y. Zhang, X.Y. Zhao, Y.L. Zhao, Y. Zhao, Z.H. ZhenHua, N. Zhou, Z.S. Zhou
IHEP, Beijing, People's Republic of China
H.Y. Zhu
Institute of High Energy Physics (IHEP), People's Republic of China

Funding: CAS Strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System) and National Natural Science Foundation of China, under contract NO. 11405190
The 10 MeV accelerator-driven subcritical system (ADS) Injector I test stand at Institute of High Energy Physics (IHEP) is a testing facility dedicated to demonstrate one of the two injector design schemes [Injector Scheme-I, which works at 325 MHz], for the ADS project in China. The ion source was installed since April of 2014, periods of commissioning are regularly scheduled between installation phases of the rest of the injector. Early this year, continuous wave (CW) proton beam has been successfully obtained with energy of 10MeV and average beam current around 2 mA, the single spoke cavities with smallest developed beta (βg=0.12) were applied and successfully commissioned. Single spoke cavities with higher beta (βg=0.21) were also adopted for the last cryomodule of 25MeV proton linac, and 170uA CW proton beam were shooting through recently. This contribution reports the details of the development of the C-ADS SRF accelerator at IHEP and the challenges of the CW machine commissioning

Slides MOXA07 [5.605 MB]

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MOPB008

Input Power Coupler for NICA Injector Coaxial Quater Wave SC Cavity

ion, cavity, multipactoring, Windows

61

M.V. Lalayan, T.A. Bakhareva, M. Gusarova, 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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MOPB012

Status of the IFMIF LIPAc SRF Linac

ion, cavity, cryomodule, SRF

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

ion, FEL, GUI, SRF

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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MOPB016

Operation of Diamond Superconducting RF Cavities

cavity, ion, vacuum, GUI

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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MOPB041

Status of the SOLEIL Superconducting RF System

ion, cavity, SRF, GUI

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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MOPB077

Operational Experience of the European-XFEL 3.9 GHz Coaxial Tuners

ion, cavity, FEL, MMI

240

R. Paparella, A. Bellandi, A. Bignami, A. Bosotti, D. Sertore
INFN/LASA, Segrate (MI), Italy
C.G. Maiano
ESS, Lund, Sweden
P. Pierini
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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MOPB097

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

ion, cavity, radiation, 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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MOPB101

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

ion, cavity, cryomodule, experiment

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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MOPB106

Test Results of the European XFEL Serial-production Accelerator Modules

ion, cavity, cryomodule, FEL

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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MOPB110

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

ion, cavity, cryomodule, SRF

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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TUPB020

Microphonics Passive Damping

ion, cavity, SRF, simulation

423

E.N. Zaplatin
FZJ, Jülich, Germany
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Different types of external loads on the resonator walls predetermine the main working conditions of the SRF cavities. The most important of them are very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape. For pulsed operation, the Lorentz forces usually play the decisive role for the cavity design. For CW operation, the liquid helium vessel pressure instability even for 2K operations is the source of large microphonics. All deformations resulting from any type of external loads on cavity walls lead to shifts in the working RF frequency in the range of hundreds of kHz. Taking into account high Q-factor of SC cavities such a large frequency shift takes the cavity out of operation. Here we present and discuss the achievements and problems of microphonics passive damping in different type SRF cavities.

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TUPB024

Performance Tests of the Superconducting 217 MHz CH Cavity for the CW Demonstrator

ion, cavity, linac, heavy-ion

440

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

Regarding the future research program of super heavy element (SHE) synthesis at GSI, high intense heavy ion beams above the coulomb barrier and high average particle currents are highly demanded. The associated beam requirements exceed the capabilities of the existing Universal Linear Accelerator (UNILAC). Besides the existing GSI accelerator chain will be exclusively used as an injector for FAIR (Facility for Antiproton and Ion Research) providing high power heavy ion beams at a low repetition rate. As a consequence a new dedicated superconducting (sc) continuous wave (cw) linac is highly demanded to keep the SHE research program at GSI competitive on a high level. In this context the construction of the first linac section, which serves simultaneously as a prototype to demonstrate its reliable operability has been finished at the end of 2016. The so called demonstrator cryomodule comprises two sc 9.3 T solenoids and a sc 217 MHz crossbar-H-mode (CH) cavity with 15 equidistant accelerating gaps. Furthermore, the performance of the cavity has been successfully tested at cryogenic temperatures. The results of these tests are presented.

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TUPB060

Innovative Cryogenic Test Facility for Testing SRF Cavity Series Production

ion, cavity, SRF, cryogenics

520

L. Bizel-Bizellot, M. Ellis, S.M. Pattalwar, M.D. Pendleton, P.A. Smith, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Testing SRF cavities in a vertical cryostat is the first step in qualifying the performance of SRF cavities before being integrated into a cryomodule. The European Spallation Source (ESS) requires 84 high-beta 5 cells, 704 MHz cavities which will be manufactured and qualified for their RF performance in a vertical cryostat at Science and Technology Facility Council (STFC) Daresbury Laboratory (United-kingdom). Taking a conventional approach each vertical test would require a large cryostat demanding more than 7000 litres of liquid helium per test for testing 3 cavities simultaneously. In order to reduce the overall operating cost, we plan to develop an alternative method to divide the liquid helium consumption by 5 by filling liquid helium only in each individual helium vessels enclosing each cavity placed horizontally in the cryostat. Therefore the test is performed in more realistic conditions such as in a cryomodule and reduces the operating time. This also reduces the mass flow-rate to be handled by a factor 10, leading to 2 g/s, thus reducing the size of the associated components such as the 2 K pumps, the safety device, the valves and transfer lines.

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TUPB064

Operating Experience on Cavity Performance of ISAC-II Superconducting Heavy Ion Linac

ion, cavity, ISAC, linac

527

Z.Y. Yao, T. Junginger, A.N. Koveshnikov, R.E. Laxdal, Y. Ma, D.W. Storey, E. Thoeng, B.S. Waraich, V. Zvyagintsev
TRIUMF, Vancouver, Canada

ISAC-II is a superconducting heavy ion linac with 40 QWRs as an extension of ISAC facility for ISOL based on radioactive ion beam production and acceleration. Phase-I with twenty 106MHz cavities has been operating since 2006. The design spec was achieved with the completion of Phase-II with another twenty 141MHz cavities in 2010. The cavity performance statistics and operating experience have been accumulated over years. This paper will summarize the operating experience on cavity performance of ISAC-II.

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TUPB065

Design of Multi-frequency Coaxial Test Resonators

ion, cavity, niobium, SRF

531

Z.Y. Yao, T. Junginger, R.E. Laxdal, B. Matheson, B.S. Waraich, V. Zvyagintsev
TRIUMF, Vancouver, Canada

A significant issue in low beta resonators is medium field Q-slope (MFQS) at 4K. To study the MFQS and the field dependence of surface resistance in low beta resonators, a quarter-wave resonator (QWR) and a half-wave resonator (HWR) were designed to be tested at integer harmonic frequencies of 200MHz, and up to 1.2GHz. A series of chemistry and heat treatments will be applied to these cavities so that a systemic study on the surface resistance of the coaxial resonators associating with post-processing, RF field, and frequency can be done. The detail design of these cavities and the status of cavity fabrication will be reported in this paper.

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TUPB070

INFN-LASA Cavity Design for PIP-II LB650 Cavity

cavity, ion, HOM, coupling

547

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

INFN-LASA is going to join the international partnership for Fermilab PIP-II project and to provide a novel design for the 650 MHz cavity of the 0.61 beta linac section, plug compatible with the Fermilab Cryomodule design. This paper reports the cavity design features both from the electro-magnetic and mechanical aspects, with focus on the rationales at the basis of the choice of main parameters. Furthermore, the current plans for the future R&D activity are here reported, including the production of two single cells and two complete cavities.

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THYA02

Achievement of Stable Pulsed Operation at 36 MV/m in STF-2 Cryomodule at KEK

ion, cavity, cryomodule, accelerating-gradient

722

Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori
KEK, Ibaraki, Japan

In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomdoule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities was successfully carried out. The main achievement is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification (2 of 8 cavities achieved 36 MV/m with piezo compensation), and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. In this paper, the result for the STF-2 cryomodule in three cooldown tests will be presented in detail.

Slides THYA02 [4.042 MB]

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THYA06

Long-term Operation Experience with Beams in Compact ERL Cryomodules

ion, cavity, linac, cryomodule

736

K. Umemori, M. Egi, K. Enami, T. Furuya, Y. Honda, E. Kako, T. Konomi, H. Sakai
KEK, Ibaraki, Japan
T. Okada
Sokendai, Ibaraki, Japan
M. Sawamura
QST, Tokai, Japan

Compact ERL (cERL) was constructed at KEK as a prototype for 3GeV ERL light source. It consists of two types of SRF cavities. Three injector 2-cell SRF cavities and two main linac 9-cell SRF cavities. The beam operation started at 2013, with 100 nA (CW). Beam current increased step by step and currently reached to 1 mA (CW). Energy recovery has successfully achieved. Performance of the SRF cavities through long term beam operation has been investigated. With the beam induced HOMs, the beam position and the beam timing were studied. cERL has suffered from heavy field emissions in operation. Field emissions of the main linac cavity started just after module assembly work, and during beam operation, performances of both the main linac and the injector SRF cavities sometimes degraded. One reason of degradation was discharges occurred at beamline components due to charge up of electrons. Pulse aging technique helped to recover SRF performances. In this presentation, details of SRF beam operation, degradation, applied recovery methods are described.

Slides THYA06 [4.973 MB]

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