LINAC2018 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPO005	Commissioning of the Normal Conducting Cavities for LEReC Project	cavity, booster, electron, MMI	44
	B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, A. Zaltsman BNL, Upton, Long Island, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is designed, and is currently under commissioning at BNL. The linac of LEReC consists of a DC photoemission gun, a 704 MHz superconducting radio frequency (SRF) booster cavity, a three-cell 2.1 GHz third harmonic cavity for RF curvature correction, a single-cell 704 MHz cavity for energy de-chirping and a 704 MHz deflecting cavity for diagnostic line. In this paper, we present the commissioning of three normal conducting cavities mentioned above.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO005
About •	paper received ※ 14 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO080	The Manufacturing of the CSNS DTL Tank	cavity, DTL, linac, factory	167
	X.L. Wu, T. Luo CSNS, Guangdong Province, People’s Republic of China L. Dong, K.Y. Gong, H.C. Liu, H. Song IHEP, Beijing, People’s Republic of China S.M. Liu DNSC, Dongguan, People’s Republic of China
	The DTL tank is a crucial component of the China Spallation Neutron Source (CSNS) linear accelerator (LINAC), which mainly use the technology of oxygen-free copper (OFC) electroplating on the inner surface of the 20# carbon steel tube. It is the first time to perform OFC electroplating with high electrical conductivity in the high intensity beam accelerator in China. In the process of cavity manufacturing, problems such as machining deformation, plating surface nodule and plating peeling are encountered. In this project, based on pre-research and information from literature, the formula of acid solution was improved to construct a stable pickling process protocol. The manufacturing process of DTL tank and the measurement details are introduced in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO080
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO089	Design Details of the European Spallation Source Drift Tube LINAC	DTL, interface, GUI, linac	190
	P. Mereu, M. Mezzano, C. Mingioni, M. Nenni INFN-Torino, Torino, Italy G. Cibinetto INFN-Ferrara, Ferrara, Italy F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy
	The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper gives a detailed overview of the ESS-DTL current mechanical design, and the related driving criteria. It presents also an outlook of the main aspects of the assembly and installation, with related equipments, toolings and procedures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO089
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO093	A Study of a Cooling Configuration for an OFHC Copper Rebuncher	cavity, simulation, linac, pick-up	200
	O. Mazor, M. Bukai, D. Nusbaum, J. Rodnizki Soreq NRC, Yavne, Israel E. Dyunin Ariel University, Ariel, Israel G. Ziskind Ben-Gurion University in the Negev, Beer Sheva, Israel
	Funding: Pazy Fund (Israel Atomic Energy commission) https://pazy.org.il A four gap OFHC copper rebuncher is developed at SNRC as a research study and a risk reduction for the MEBT of SARAF Phase II proton/ deuteron linac. The rebuncher is designed to bunch a 5 mA CW beam at 176 MHz. The required cavity voltage according to beam dynamics evaluation is 150 kV with a beam aperture diameter of 40 mm at a beam energy of 1.3 MeV/u with a Q value of 8000. Considering utilizing this cavity for enhancing the beam energy, the cooling configuration is explored for a cavity voltage of 300 kV, consuming 20 kW dissipated power, at a peak electric field of 16 MV/m, equivalent to the Kilpatrick limit. The electro magnetic study conducted with the CST RF simulation package was reproduced at ANSYS HFSS. The simulated dissipated power along the rebuncher for 20 kW forward power injected through the coupler port with the HFSS driven model were assigned to the ANSYS Fluent model to explore the resulted temperature map. Several evolved cooling configurations were studied, including cooling of the drift tubes. In this configuration the temperature rise along the cavity is in the range of 30 K. A detailed design of the four gap rebuncher is following this study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO093
About •	paper received ※ 03 September 2018 paper accepted ※ 22 September 2018 issue date ※ 18 January 2019
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MOPO124	Details of the Manufacturing Processes of the ESS-DTL Components	DTL, alignment, coupling, linac	260
	P. Mereu, F. Borotto Dalla Vecchia, C. Mingioni, M. Nenni, R. Panero INFN-Torino, Torino, Italy A. Battistello, P. Bottin, D. Conventi, L. Ferrari, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy A.G. Colombo INFN- Sez. di Padova, Padova, Italy
	The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper presents the details of the manufacturing processes with quality control reports of the components of the DTL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO124
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TU1A01	Challenges in Superconducting Accelerating Module Design and Construction for High Power Proton Accelerators	cryomodule, cavity, linac, alignment	280
	C. Madec CEA/DSM/IRFU, France
	CEA is engaged in the construction of the IFMIF, SARAF and ESS superconducting linacs and in particular in the design and production of a their accelerating cryomodules: 1 low-beta half-wave 176 MHz resonators for IFMIF, 4 low-beta half-wave 176 MHz resonators for SARAF and 30 medium and high-beta elliptical cavity resonators for ESS. The developments of these RF cryomodules, although at various stages, are led in parallel by the cryomodule team at CEA-Saclay, including all RF, mechanical, thermal, cryogenic, integration and QA-QC aspects in a global approach which attempts to optimise synergies and lessons learnt between these projects. A status report will be presented describing the common approaches and methods, and the systemic particularities of each project.
	Slides TU1A01 [11.896 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A01
About •	paper received ※ 14 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019
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TUPO009	Heat Treatment for a Prototype Half-Wave Resonator Cavity	cavity, niobium, SRF, lattice	339
	Y. Jung, B.H. Choi, J. Joo, H.C. Jung, H. Kim, J.W. Kim, Y. Kim, J. Lee, S. Lee IBS, Daejeon, Republic of Korea
	Heat treatment, 650C for 10hrs, was carried out to improve the performance of a half-wave resonator cavity. In this presentation, we report how the heat treatment was performed. X-ray diffraction analysis and residual gas analysis were performed to investigate the effect of the heat treatment on the cavity performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO009
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO028	Retreatment of European XFEL Series Cavities at DESY as Part of the Repair of European XFEL Accelerating Modules	cavity, FEL, SRF, linac	384
	S. Sievers, N. Krupka, D. Reschke, S. Saegebarth, J. Schaffran, M. Schalwat, P. Schilling, M. Schmökel, N. Steinhau-Kühl, E. Vogel, H. Weise, B. van der Horst DESY, Hamburg, Germany M. Wiencek IFJ-PAN, Kraków, Poland
	For the European XFEL 10² accelerating modules were built and tested. Several accelerating modules had to be reworked due to different kinds of non-conformities. The extent of this rework varied greatly. At the end of production four accelerating modules could not be qualified in time before the tunnel installation was to be finished in September 2016. Meanwhile the cavity strings of two of these accelerating modules have been disassembled in the DESY clean room. The cavities have been retreated at DESY either by additional high pressure water rinsing or BCP flash chemical treatment. All cavities were vertically tested and 15 out of 16 were qualified for the reassembly of the cavity strings. One accelerating module will be reassembled completely and tested until the end of 2018; the other will follow in the first half of 2019. We report on retreatment procedures and performance of these cavities.
	Poster TUPO028 [1.662 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO028
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO041	LCLS-II Cavity Higher Order Modes Coupler Tuning Optimization and Challenges at Jefferson Lab	HOM, cavity, cryomodule, target	423
	A.D. Solopova, D. Forehand, A.D. Palczewski JLab, Newport News, Virginia, USA T.N. Khabiboulline Fermilab, Batavia, Illinois, USA
	LCLS-II is a new XFEL linac based on 1.3GHz SRF linac. Half of the LCLS-II cryomodules are being produced at Jefferson Lab. This paper summarizes the Higher Order Mode filter tuning challenges at Jefferson Lab and describes optimization of the procedure for a 9-cell Tesla type cavity and its integration into a cryomodule production line.
	Poster TUPO041 [0.719 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO041
About •	paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO049	Nitrogen Doping Study With 1.3 GHz Single Cell Superconducting Cavities	cavity, accelerating-gradient, niobium, superconducting-cavity	442
	S. Chen, M. Chen, L.W. Feng, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan, F. Wang, F. Zhu PKU, Beijing, People’s Republic of China
	Nitrogen doping studies were carried out at Peking University. A series of 1.3 GHz single cell cavities fabricated with OTIC large grain niobium material were annealed and doped in the furnace of Peking University, and electropolished by a simple EP device. Light doping recipe and heavy doping recipe are both adopted for comparison. The results and analysis are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO049
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO053	Fabrication of Nb Mushroom Shaped Cavity for Evaluation of Multi-layer Thin-film Superconductor	cavity, electromagnetic-fields, cryogenics, superconducting-cavity	454
	H. Oikawa Utsunomiya University, Utsunomiya, Japan K. Enami, H. Hayano, H. Inoue KEK, Ibaraki, Japan T. Higashiguchi Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
	The accelerating gradient of the Nb superconducting RF cavity seems to reach the limit due to the RF critical magnetic field of the Nb material. To obtain more higher gradient, there has been proposed a method of increasing an RF critical magnetic field of the cavity inner surface by coating of multi-layer thin-film superconductor. It is needed to demonstrate improvement RF critical magnetic field of the RF cavity coated with multi-layer thin-film superconductor. To optimize thin-film superconductor, sample tests are required. A cavity for sample test is necessary to produce a strong RF magnetic field parallel to the surface of the sample for evaluating RF critical magnetic field. For such a cavity, we designed a mushroom shaped cavity made of Nb which is operated in cryogenic temperature. Input and pick up antenna coupler are also designed electrically and mechanically. The connection design of sample plate and cavity bottom plate in superconducting state is also designed. The Nb mushroom shaped cavity is under fabrication. Fabrication method and status are reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO053
About •	paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO070	Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development	cavity, injection, MMI, operation	496
	K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai KEK, Ibaraki, Japan
	Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10^-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070
About •	paper received ※ 19 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO071	Study on Nitrogen Infusion for 1.3 GHz SRF Cavities Using J-PARC Furnace	cavity, SRF, injection, background	499
	K. Umemori, T. Dohmae, M. Egi, Y. Hori, E. Kako, T. Konomi, S. Michizono, T. Saeki, H. Sakai, Y. Yamamoto KEK, Ibaraki, Japan J. Kamiya JAEA/J-PARC, Tokai-mura, Japan S. Kurosawa, K. Takeishi JAEA, Ibaraki-ken, Japan T. Okada Sokendai, Ibaraki, Japan
	Nitrogen infusion (N-infusion) is new surface treatment technique for niobium SRF (Superconducting RF) cavities. After cooling down from 800 degree C heat treatment, a vacuum furnace and cavities are kept 120 degree C, 48 hours with about 3 Pa Nitrogen. Improvement of Q-value and accelerating gradient is expected. We used J-PARC furnace, since N-infusion procedure requires clean vacuum furnace. It has a cryo-pump and turbo molecular pumps and its vacuum system is oil-free system. Six times of N-infusion tests were carried out, while changing vacuum condition, N-infusion temperature, Nitrogen pressure, niobium material and so on. Niobium caps were mounted on cavities to avoid contaminations on inner surfaces. Some of trials were successful and vertical test results showed improvement of Q-values and accelerating gradient. However, some of them were not. Most of bad cases showed degradation of Q-values above 5 MV/m. Details of heat treatment procedure including N-infusion and vertical test results are shown in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO071
About •	paper received ※ 20 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO072	First Trial of the In-situ Nitrogen Infusion at KEK	cavity, controls, SRF, niobium	503
	T. Konomi, T. Dohmae, E. Kako, S. Michizono, H. Sakai, K. Umemori KEK, Ibaraki, Japan T. Okada Sokendai, Ibaraki, Japan
	The nitrogen infusion is the new surface treatment technique for improving the RF loss and the maximum accelerating gradient of superconducting cavity. In this process, it is important to be carried out continuously both the 800 C annealing in vacuum and 120 C nitrogen infusion without exposure to the atmosphere. The annealing serves activation process by removing the oxide layer. The in-situ nitrogen infusion system was prepared to investigate whether nitrogen infusion effect or something changes happen in the case of applying nitrogen infusion technique without removing the oxide layer. It can only introduce nitrogen into a cavity during 120 C low temperature baking and transport a cavity to the vertical test system without exposure to the atmosphere. We tried to infuse nitrogen to a single cell by keeping 120 C and 48 hours with 3 Pa nitrogen. The cavity was annealed in another furnace and applied high pressure rinsing before nitrogen infusion. The vertical test result was same Q as the normal 120 C baking without nitrogen. It suggests that oxide layer prevents infusion of nitrogen. In this poster, the in-situ nitrogen infusion system and vertical test results will be reported.
	Poster TUPO072 [4.653 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO072
About •	paper received ※ 12 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO073	Niobium Sample Analysis for Nitrogen Infusion and Doping	cavity, niobium, injection, ECR	506
	T. Konomi, E. Kako, S. Michizono, H. Sakai, K. Umemori KEK, Ibaraki, Japan T. Nagata ULVAC, Inc., Tsukuba, Japan T. Nojima Tohoku University, Sendai, Japan
	KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO073
About •	paper received ※ 18 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO113	Beam Dynamics Studies Through Dielectric THz Accelerating Structures	GUI, simulation, accelerating-gradient, linac	569
	R. Apsimon, G. Burt, A.L. Healy, S.P. Jamison Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R.B. Appleby, E.J.H. Smith UMAN, Manchester, United Kingdom A. Latina CERN, Geneva, Switzerland
	As conventional RF accelerating schemes approach the physical limit of accelerating gradient, the accelerator community is increasingly looking at novel accelerating techniques to overcome these limitations. Moving from the RF to the THz frequency range, higher acceleration gradients of high energy beams can be achieved in compact structures. Beam dynamics studies are crucial as part of the design of novel accelerating structures to maximise the output beam current as well as the accelerating gradient. In this paper we present beam dynamics simulations through dielectric lined waveguide structures using novel techniques to simulate broadband signals for particle tracking studies in RF-Track. The beam parameters through the structure are optimised and we study the dynamics of general broadband accelerating structures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO113
About •	paper received ※ 13 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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WE2A03	Construction Status of the Superconducting Linac at RIKEN RIBF	cavity, linac, cryomodule, DTL	620
	N. Sakamoto, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, K. Suda, T. Watanabe, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan H. Hara, T. Yanagisawa MHI, Hiroshima, Japan E. Kako, H. Nakai, H. Sakai, K. Umemori KEK, Ibaraki, Japan A. Miyamoto, K. Sennyu MHI-MS, Kobe, Japan
	An upgrade project of the RIKEN Heavy-Ion Linac, RILAC, is under going, which aims at the further investigation of the super-heavy elements and production of radioactive isotopes for medical applications. In this project, a new superconducting ECR ion source and superconducting RF (SRF) booster linac are being developed and constructed. The SRF linac consists of 10 quarter-wavelength resonator operated at 73 MHz, that are contained in three cryomodules. The construction status, including the first vertical test results, will be given in this paper.
	Slides WE2A03 [23.169 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A03
About •	paper received ※ 14 September 2018 paper accepted ※ 17 October 2018 issue date ※ 18 January 2019
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THPO008	Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK	cavity, operation, linac, cryomodule	695
	H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori KEK, Ibaraki, Japan
	We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO030	Operation Experience of the CSNS DTL	DTL, MMI, operation, linac	744
	H.C. Liu, Q. Chen, S. Fu, K.Y. Gong IHEP, Beijing, People’s Republic of China M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) Drift tube linac (DTL) accelerates H⁻ beam from 3 to 80MeV with 4 independent tanks. The 80MeV beam acceleration was achieved in January 2018. The linac is a key to the reliability of the whole CSNS facility since all the beams stop when these upstream facilities fail. Many efforts have been made for DTL reliable operation. This paper presents the operation experience learned in DTL com-missioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO030
About •	paper received ※ 28 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO031	RF Conditioning and Beam Commissioning Status of CSNS DTL	DTL, cavity, operation, MMI	747
	Y. Wang, M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liu IHEP, Beijing, People’s Republic of China
	The high power RF conditioning of CSNS DTL was finished in April 2017 with peak input power 1.6MW, 650us pulse width, 25Hz repetition frequency. With careful tuning of RF amplitude and phase, beam was accelerated to 80MeV successfully with maximum peak beam current 12mA and about 98% transmission efficiency. DTL operate stably at full power level with several trips per day without beam interruption after six months commissioning. The whole RF conditioning process was presented and some details of beam commissioning were described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO031
About •	paper received ※ 05 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO038	Status of the Power Couplers for the CSNS DTL	DTL, coupling, cavity, operation	767
	M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liu IHEP, Beijing, People’s Republic of China
	There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10^-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented. This work was supported by Youth Innovation Promotion Association of CAS (2015011)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038
About •	paper received ※ 30 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO080	Design Validation of a Chopping and Deflecting System for the High Current Injector at IUAC	experiment, diagnostics, simulation, power-supply	869
	S. Kedia, R. Ahuja, R. Kumar, R. Mehta IUAC, New Delhi, India
	A chopping and deflecting system has been designed and developed to provide the chopped beam with various repetition rates at the IUAC experimental facilities. It consists of four pairs of deflecting plates with increasing gap from 15 mm to 21 mm to maximize the effective electric field, preserve the beam emittance and to maximize the transmission efficiency within the same voltage conditions. The design of CDS has been validated with various simulation codes like CST MWS, Solid Works, Python and TRACE 3D. The deflecting plates have been fabricated, and assembled with in the design accuracy of 100 microns. A vacuum chamber has been designed and fabricated to incorporate the deflector plate assembly. The CDS unit has been installed in the Low Energy Ion Beam Facility at the IUAC to validate the design value of ion beam deflection. A slit has been installed to cut the deflected charge particles. Since the pulse power electronics required for chopping is presently under design we have used DC voltage across the four pairs of deflecting plates and amount of deflection was measured accordingly. The design, development, and DC beam test will be discussed in the article.
	Poster THPO080 [2.037 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO080
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO083	Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro	cavity, diagnostics, emittance, impedance	875
	G. Kourkafas, T. Kamps, A. Neumann HZB, Berlin, Germany B. Keune RI Research Instruments GmbH, Bergisch Gladbach, Germany
	The Berlin Energy Recovery Linac Prototype (BERLinPro) at Helmholtz Zentrum Berlin (HZB) aims to deliver a continuous-wave electron beam of high average current (100 mA) and brilliance (normalized emittance below 1 mm mrad). The achievement of these ambitious goals necessitates a thorough determination of the bunch parameters after the first acceleration stages, namely the photoinjector and the succeeding booster module. For the measurement of primarily the bunch duration and subsequently the longitudinal phase space and transverse slice emittance, a single-cell 1.3-GHz TM110-like mode vertically deflecting cavity was manufactured by RI Research Instruments GmbH, following the respective design developed for the Cornell ERL injector. This article summarizes the design parameters, manufacturing procedure and testing of this pulsed RF resonator, together with the expected temporal measurement resolution for the nominal beam energies at the initial acceleration stages of BERLinPro.
	Poster THPO083 [1.396 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO083
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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Paper

Title

Other Keywords

Page

MOPO005

Commissioning of the Normal Conducting Cavities for LEReC Project

cavity, booster, electron, MMI

44

B. P. Xiao, K. Mernick, F. Severino, K.S. Smith, T. Xin, A. Zaltsman
BNL, Upton, Long Island, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is designed, and is currently under commissioning at BNL. The linac of LEReC consists of a DC photoemission gun, a 704 MHz superconducting radio frequency (SRF) booster cavity, a three-cell 2.1 GHz third harmonic cavity for RF curvature correction, a single-cell 704 MHz cavity for energy de-chirping and a 704 MHz deflecting cavity for diagnostic line. In this paper, we present the commissioning of three normal conducting cavities mentioned above.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO005

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paper received ※ 14 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO080

The Manufacturing of the CSNS DTL Tank

cavity, DTL, linac, factory

167

X.L. Wu, T. Luo
CSNS, Guangdong Province, People’s Republic of China
L. Dong, K.Y. Gong, H.C. Liu, H. Song
IHEP, Beijing, People’s Republic of China
S.M. Liu
DNSC, Dongguan, People’s Republic of China

The DTL tank is a crucial component of the China Spallation Neutron Source (CSNS) linear accelerator (LINAC), which mainly use the technology of oxygen-free copper (OFC) electroplating on the inner surface of the 20# carbon steel tube. It is the first time to perform OFC electroplating with high electrical conductivity in the high intensity beam accelerator in China. In the process of cavity manufacturing, problems such as machining deformation, plating surface nodule and plating peeling are encountered. In this project, based on pre-research and information from literature, the formula of acid solution was improved to construct a stable pickling process protocol. The manufacturing process of DTL tank and the measurement details are introduced in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO080

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

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MOPO089

Design Details of the European Spallation Source Drift Tube LINAC

DTL, interface, GUI, linac

190

P. Mereu, M. Mezzano, C. Mingioni, M. Nenni
INFN-Torino, Torino, Italy
G. Cibinetto
INFN-Ferrara, Ferrara, Italy
F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy

The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper gives a detailed overview of the ESS-DTL current mechanical design, and the related driving criteria. It presents also an outlook of the main aspects of the assembly and installation, with related equipments, toolings and procedures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO089

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

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MOPO093

A Study of a Cooling Configuration for an OFHC Copper Rebuncher

cavity, simulation, linac, pick-up

200

O. Mazor, M. Bukai, D. Nusbaum, J. Rodnizki
Soreq NRC, Yavne, Israel
E. Dyunin
Ariel University, Ariel, Israel
G. Ziskind
Ben-Gurion University in the Negev, Beer Sheva, Israel

Funding: Pazy Fund (Israel Atomic Energy commission) https://pazy.org.il
A four gap OFHC copper rebuncher is developed at SNRC as a research study and a risk reduction for the MEBT of SARAF Phase II proton/ deuteron linac. The rebuncher is designed to bunch a 5 mA CW beam at 176 MHz. The required cavity voltage according to beam dynamics evaluation is 150 kV with a beam aperture diameter of 40 mm at a beam energy of 1.3 MeV/u with a Q value of 8000. Considering utilizing this cavity for enhancing the beam energy, the cooling configuration is explored for a cavity voltage of 300 kV, consuming 20 kW dissipated power, at a peak electric field of 16 MV/m, equivalent to the Kilpatrick limit. The electro magnetic study conducted with the CST RF simulation package was reproduced at ANSYS HFSS. The simulated dissipated power along the rebuncher for 20 kW forward power injected through the coupler port with the HFSS driven model were assigned to the ANSYS Fluent model to explore the resulted temperature map. Several evolved cooling configurations were studied, including cooling of the drift tubes. In this configuration the temperature rise along the cavity is in the range of 30 K. A detailed design of the four gap rebuncher is following this study.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO093

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paper received ※ 03 September 2018 paper accepted ※ 22 September 2018 issue date ※ 18 January 2019

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MOPO124

Details of the Manufacturing Processes of the ESS-DTL Components

DTL, alignment, coupling, linac

260

P. Mereu, F. Borotto Dalla Vecchia, C. Mingioni, M. Nenni, R. Panero
INFN-Torino, Torino, Italy
A. Battistello, P. Bottin, D. Conventi, L. Ferrari, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
A.G. Colombo
INFN- Sez. di Padova, Padova, Italy

The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper presents the details of the manufacturing processes with quality control reports of the components of the DTL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO124

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

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TU1A01

Challenges in Superconducting Accelerating Module Design and Construction for High Power Proton Accelerators

cryomodule, cavity, linac, alignment

280

C. Madec
CEA/DSM/IRFU, France

CEA is engaged in the construction of the IFMIF, SARAF and ESS superconducting linacs and in particular in the design and production of a their accelerating cryomodules: 1 low-beta half-wave 176 MHz resonators for IFMIF, 4 low-beta half-wave 176 MHz resonators for SARAF and 30 medium and high-beta elliptical cavity resonators for ESS. The developments of these RF cryomodules, although at various stages, are led in parallel by the cryomodule team at CEA-Saclay, including all RF, mechanical, thermal, cryogenic, integration and QA-QC aspects in a global approach which attempts to optimise synergies and lessons learnt between these projects. A status report will be presented describing the common approaches and methods, and the systemic particularities of each project.

Slides TU1A01 [11.896 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A01

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paper received ※ 14 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019

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TUPO009

Heat Treatment for a Prototype Half-Wave Resonator Cavity

cavity, niobium, SRF, lattice

339

Y. Jung, B.H. Choi, J. Joo, H.C. Jung, H. Kim, J.W. Kim, Y. Kim, J. Lee, S. Lee
IBS, Daejeon, Republic of Korea

Heat treatment, 650C for 10hrs, was carried out to improve the performance of a half-wave resonator cavity. In this presentation, we report how the heat treatment was performed. X-ray diffraction analysis and residual gas analysis were performed to investigate the effect of the heat treatment on the cavity performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO009

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

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TUPO028

Retreatment of European XFEL Series Cavities at DESY as Part of the Repair of European XFEL Accelerating Modules

cavity, FEL, SRF, linac

384

S. Sievers, N. Krupka, D. Reschke, S. Saegebarth, J. Schaffran, M. Schalwat, P. Schilling, M. Schmökel, N. Steinhau-Kühl, E. Vogel, H. Weise, B. van der Horst
DESY, Hamburg, Germany
M. Wiencek
IFJ-PAN, Kraków, Poland

For the European XFEL 10² accelerating modules were built and tested. Several accelerating modules had to be reworked due to different kinds of non-conformities. The extent of this rework varied greatly. At the end of production four accelerating modules could not be qualified in time before the tunnel installation was to be finished in September 2016. Meanwhile the cavity strings of two of these accelerating modules have been disassembled in the DESY clean room. The cavities have been retreated at DESY either by additional high pressure water rinsing or BCP flash chemical treatment. All cavities were vertically tested and 15 out of 16 were qualified for the reassembly of the cavity strings. One accelerating module will be reassembled completely and tested until the end of 2018; the other will follow in the first half of 2019. We report on retreatment procedures and performance of these cavities.

Poster TUPO028 [1.662 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO028

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

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TUPO041

LCLS-II Cavity Higher Order Modes Coupler Tuning Optimization and Challenges at Jefferson Lab

HOM, cavity, cryomodule, target

423

A.D. Solopova, D. Forehand, A.D. Palczewski
JLab, Newport News, Virginia, USA
T.N. Khabiboulline
Fermilab, Batavia, Illinois, USA

LCLS-II is a new XFEL linac based on 1.3GHz SRF linac. Half of the LCLS-II cryomodules are being produced at Jefferson Lab. This paper summarizes the Higher Order Mode filter tuning challenges at Jefferson Lab and describes optimization of the procedure for a 9-cell Tesla type cavity and its integration into a cryomodule production line.

Poster TUPO041 [0.719 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO041

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

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TUPO049

Nitrogen Doping Study With 1.3 GHz Single Cell Superconducting Cavities

cavity, accelerating-gradient, niobium, superconducting-cavity

442

S. Chen, M. Chen, L.W. Feng, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan, F. Wang, F. Zhu
PKU, Beijing, People’s Republic of China

Nitrogen doping studies were carried out at Peking University. A series of 1.3 GHz single cell cavities fabricated with OTIC large grain niobium material were annealed and doped in the furnace of Peking University, and electropolished by a simple EP device. Light doping recipe and heavy doping recipe are both adopted for comparison. The results and analysis are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO049

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

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TUPO053

Fabrication of Nb Mushroom Shaped Cavity for Evaluation of Multi-layer Thin-film Superconductor

cavity, electromagnetic-fields, cryogenics, superconducting-cavity

454

H. Oikawa
Utsunomiya University, Utsunomiya, Japan
K. Enami, H. Hayano, H. Inoue
KEK, Ibaraki, Japan
T. Higashiguchi
Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan

The accelerating gradient of the Nb superconducting RF cavity seems to reach the limit due to the RF critical magnetic field of the Nb material. To obtain more higher gradient, there has been proposed a method of increasing an RF critical magnetic field of the cavity inner surface by coating of multi-layer thin-film superconductor. It is needed to demonstrate improvement RF critical magnetic field of the RF cavity coated with multi-layer thin-film superconductor. To optimize thin-film superconductor, sample tests are required. A cavity for sample test is necessary to produce a strong RF magnetic field parallel to the surface of the sample for evaluating RF critical magnetic field. For such a cavity, we designed a mushroom shaped cavity made of Nb which is operated in cryogenic temperature. Input and pick up antenna coupler are also designed electrically and mechanically. The connection design of sample plate and cavity bottom plate in superconducting state is also designed. The Nb mushroom shaped cavity is under fabrication. Fabrication method and status are reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO053

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

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TUPO070

Design and Commissioning of KEK New Vacuum Furnace for SRF Cavity Development

cavity, injection, MMI, operation

496

K. Umemori, M. Egi, E. Kako, T. Konomi, S. Michizono, H. Sakai
KEK, Ibaraki, Japan

Recently new techniques such as Nitrogen-doping and Nitrogen-infusion have been developed to improve performance of SRF (Superconducting RF) cavities. We purchased a new vacuum furnace, which is key to realize these techniques. Cleanness of the furnace is most important issue. The furnace has a cryo-pump and whole of vacuum system is oil-free system. Target vacuum level after cooling down is 1x10^-6 Pa. Heater, reflectors and support table were made from Molybdenum to avoid contamination during heat treatment. Metal gaskets are used for all vacuum seals, except big doors. Maximum operation temperature is 1150 degree C. Size is around 1 m diameter and 2m long for a 1.3 GHz 9-cell cavity. Entrance of furnace is covered by a clean booth. The furnace was fabricated, assembled at KEK COI building and commissioned this year. After several burning runs, target vacuum pressure was achieved after cooling down to room temperature. Design of the furnace and performance during commissioning runs are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO070

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

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TUPO071

Study on Nitrogen Infusion for 1.3 GHz SRF Cavities Using J-PARC Furnace

cavity, SRF, injection, background

499

K. Umemori, T. Dohmae, M. Egi, Y. Hori, E. Kako, T. Konomi, S. Michizono, T. Saeki, H. Sakai, Y. Yamamoto
KEK, Ibaraki, Japan
J. Kamiya
JAEA/J-PARC, Tokai-mura, Japan
S. Kurosawa, K. Takeishi
JAEA, Ibaraki-ken, Japan
T. Okada
Sokendai, Ibaraki, Japan

Nitrogen infusion (N-infusion) is new surface treatment technique for niobium SRF (Superconducting RF) cavities. After cooling down from 800 degree C heat treatment, a vacuum furnace and cavities are kept 120 degree C, 48 hours with about 3 Pa Nitrogen. Improvement of Q-value and accelerating gradient is expected. We used J-PARC furnace, since N-infusion procedure requires clean vacuum furnace. It has a cryo-pump and turbo molecular pumps and its vacuum system is oil-free system. Six times of N-infusion tests were carried out, while changing vacuum condition, N-infusion temperature, Nitrogen pressure, niobium material and so on. Niobium caps were mounted on cavities to avoid contaminations on inner surfaces. Some of trials were successful and vertical test results showed improvement of Q-values and accelerating gradient. However, some of them were not. Most of bad cases showed degradation of Q-values above 5 MV/m. Details of heat treatment procedure including N-infusion and vertical test results are shown in this presentation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO071

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

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TUPO072

First Trial of the In-situ Nitrogen Infusion at KEK

cavity, controls, SRF, niobium

503

T. Konomi, T. Dohmae, E. Kako, S. Michizono, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
T. Okada
Sokendai, Ibaraki, Japan

The nitrogen infusion is the new surface treatment technique for improving the RF loss and the maximum accelerating gradient of superconducting cavity. In this process, it is important to be carried out continuously both the 800 C annealing in vacuum and 120 C nitrogen infusion without exposure to the atmosphere. The annealing serves activation process by removing the oxide layer. The in-situ nitrogen infusion system was prepared to investigate whether nitrogen infusion effect or something changes happen in the case of applying nitrogen infusion technique without removing the oxide layer. It can only introduce nitrogen into a cavity during 120 C low temperature baking and transport a cavity to the vertical test system without exposure to the atmosphere. We tried to infuse nitrogen to a single cell by keeping 120 C and 48 hours with 3 Pa nitrogen. The cavity was annealed in another furnace and applied high pressure rinsing before nitrogen infusion. The vertical test result was same Q as the normal 120 C baking without nitrogen. It suggests that oxide layer prevents infusion of nitrogen. In this poster, the in-situ nitrogen infusion system and vertical test results will be reported.

Poster TUPO072 [4.653 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO072

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

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TUPO073

Niobium Sample Analysis for Nitrogen Infusion and Doping

cavity, niobium, injection, ECR

506

T. Konomi, E. Kako, S. Michizono, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
T. Nagata
ULVAC, Inc., Tsukuba, Japan
T. Nojima
Tohoku University, Sendai, Japan

KEK has been investigating the better conditions of the heat treatment in nitrogen, which are called as nitrogen doping and nitrogen infusion. We have tried to understand the high gradient performance of the cavity from the analyses of samples which were prepared in the same conditions for the cavity. The main tools are D-SIMS for the depth profile of the elemental concentration, XPS for composition analysis and SQUID magnetometry for the critical DC magnetic field measurement. The difference in the depth profiles of the nitrogen, carbon and oxygen between the heat treatment conditions was observed in vacuum and furnace temperature of nitrogen infusion by D-SIMS and XPS. Such a difference correlates with the vortex penetration field measured by SQUID. In particular, that of nitrogen doping sample was greatly degraded, while that of nitrogen infusion sample was slightly improved. The tendency is similar to the RF high gradient test results. Details of the sample analysis are shown in this presentation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO073

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

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TUPO113

Beam Dynamics Studies Through Dielectric THz Accelerating Structures

GUI, simulation, accelerating-gradient, linac

569

R. Apsimon, G. Burt, A.L. Healy, S.P. Jamison
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R.B. Appleby, E.J.H. Smith
UMAN, Manchester, United Kingdom
A. Latina
CERN, Geneva, Switzerland

As conventional RF accelerating schemes approach the physical limit of accelerating gradient, the accelerator community is increasingly looking at novel accelerating techniques to overcome these limitations. Moving from the RF to the THz frequency range, higher acceleration gradients of high energy beams can be achieved in compact structures. Beam dynamics studies are crucial as part of the design of novel accelerating structures to maximise the output beam current as well as the accelerating gradient. In this paper we present beam dynamics simulations through dielectric lined waveguide structures using novel techniques to simulate broadband signals for particle tracking studies in RF-Track. The beam parameters through the structure are optimised and we study the dynamics of general broadband accelerating structures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO113

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

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WE2A03

Construction Status of the Superconducting Linac at RIKEN RIBF

cavity, linac, cryomodule, DTL

620

N. Sakamoto, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, K. Suda, T. Watanabe, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
H. Hara, T. Yanagisawa
MHI, Hiroshima, Japan
E. Kako, H. Nakai, H. Sakai, K. Umemori
KEK, Ibaraki, Japan
A. Miyamoto, K. Sennyu
MHI-MS, Kobe, Japan

An upgrade project of the RIKEN Heavy-Ion Linac, RILAC, is under going, which aims at the further investigation of the super-heavy elements and production of radioactive isotopes for medical applications. In this project, a new superconducting ECR ion source and superconducting RF (SRF) booster linac are being developed and constructed. The SRF linac consists of 10 quarter-wavelength resonator operated at 73 MHz, that are contained in three cryomodules. The construction status, including the first vertical test results, will be given in this paper.

Slides WE2A03 [23.169 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A03

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paper received ※ 14 September 2018 paper accepted ※ 17 October 2018 issue date ※ 18 January 2019

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THPO008

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

cavity, operation, linac, cryomodule

695

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

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

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

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

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THPO030

Operation Experience of the CSNS DTL

DTL, MMI, operation, linac

744

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

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

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

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

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THPO031

RF Conditioning and Beam Commissioning Status of CSNS DTL

DTL, cavity, operation, MMI

747

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

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

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

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

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THPO038

Status of the Power Couplers for the CSNS DTL

DTL, coupling, cavity, operation

767

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

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

DOI •

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

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

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THPO080

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

experiment, diagnostics, simulation, power-supply

869

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

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

Poster THPO080 [2.037 MB]

DOI •

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

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

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THPO083

Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro

cavity, diagnostics, emittance, impedance

875

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

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

Poster THPO083 [1.396 MB]

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

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

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