Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Jameson, R. A.*; Yee-Rendon, B.
Journal of Instrumentation (Internet), 17(12), p.P12011_1 - P12011_11, 2022/12
Times Cited Count：0 Percentile：0(Instruments & Instrumentation)A new application of vane modulation variation in a Radio Frequency Quadrupole (RFQ) cell has been applied that significantly improves beam bunching and longitudinal emittance control to achieve lower longitudinal rms emittance at the RFQ output. This procedure occurs in the individual cells, is independent of the overall design, and therefore is general, affording an extra parameter for beam manipulation. It can be applied besides the usual goals of vane modulation variation, e.g., to achieve higher acceleration efficiency. Examples of the cumulative effects on the overall design are provided to point out further exploration avenues for the designer.
Morishita, Takatoshi; Kondo, Yasuhiro; Oguri, Hidetomo; Hasegawa, Kazuo
Journal of Vacuum Science and Technology A, 35(4), p.041602_1 - 041602_5, 2017/07
Times Cited Count：1 Percentile：4.92(Materials Science, Coatings & Films)In the J-PARC, the linac provides 400 MeV hydrogen negative ion beam to the following 3GeV synchrotron. For the beam current upgrade, the new radio-frequency quadrupole (RFQ) linac, in which the design peak beam current was increased from 30 to 50 mA, has been fabricated and installed in the beam line in summer 2014. The beam provision to users started in the beginning of November, 2014. Since then, the RFQ operates without serious problems for more than two years, however, the operation stability of the RFQ with beam acceleration was not enough due to the sparking in the cavity. We consider that the impurities in the vacuum chamber are related to this sparking phenomena. The design and performance of the RFQ vacuum system is described in this paper, then, the relationship among the sparking rates, the residual gas species in the vacuum chamber, and the beam operation parameters are described.
Maebara, Sunao; Sukegawa, Keiichi*; Tadano, Shuya*; Kasugai, Atsushi; Suzuki, Hiromitsu; Abe, Kazuhiko*; Oku, Ryuji*; Sugimoto, Masayoshi
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1140 - 1142, 2015/09
For the IFMIF/EVEDA accelerator prototype RFQ linac, the operation frequency of 175MHz was selected to accelerate a large current of 125mA. The driving RF power of 1.28MW by 8 RF input couplers has to be injected to the RFQ cavity for CW operation mode. For each RF input coupler, nominal RF power of 160kW and maximum transmitted RF power of 200kW are required. For this purpose, an RF input coupler with cooling functions was designed, based on a 6 1/8 inch co-axial waveguide, and the RF coupler was manufactured by way of trial. For the trial RF coupler, high-power tests using a high voltage standing wave on a high-Q load circuit wave were carried out, and a 200kW-14 sec CW operation were performed after four days of RF aging. No RF contact defects, unnecessary low-Q value and extraordinary outgassing were observed. This report describes the high-power tests of the RF input coupler.
Sawabe, Yuki; Ito, Yuichi; Kawase, Masato; Fukuta, Shimpei; Suzuki, Takahiro*; Kikuzawa, Nobuhiro; Ouchi, Nobuo
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.748 - 751, 2014/10
no abstracts in English
Maebara, Sunao; Moriyama, Shinichi; Saigusa, Mikio*; Sugimoto, Masayoshi; Imai, Tsuyoshi; Takeuchi, Hiroshi
Fusion Engineering and Design, 75-79, p.823 - 827, 2005/11
Times Cited Count：2 Percentile：17.6(Nuclear Science & Technology)An RF-Input coupler with a multi-loop antenna using co-axial waveguides has been developed for the RFQ linac on IFMIF. In case of using a loop antenna, the loop antenna structure will affected phase difference and power balance in each cavity. A mock-up loop antenna using the pipe diameter of 10mm was fabricated, phase differences and power balances were measured by a low power test. It is found that it is necessary to shorten the installed depth up to 3 cm to make the phase differences and power balance small. But, from a withstanding voltage, it is difficult to couple multi-MW with the single coupler. The coupling with multi-loop antennas using two or four loops is better than one loop antenna from the point views of both withstanding voltage and power balance. The phase difference and power balance were also measured in both cases. A good average phase-difference of 179
. and a good RF power balance within 8% error for each cavity were obtained. These results showed one of feasibility for an RF-Input coupler with a multi-loop antenna in the IFMIF 175 MHz RFQ.
Maebara, Sunao; Moriyama, Shinichi; Saigusa, Mikio*; Sugimoto, Masayoshi; Imai, Tsuyoshi*; Takeuchi, Hiroshi
Fusion Science and Technology, 47(4), p.941 - 945, 2005/05
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)For tuning the 175MHz RFQ used in the baseline design of IFMIF, the RF power-balance control by slug tuner is indispensable because the RF power-balance for quadrupole operation mode (TE
) in each RFQ quadrant will be affected by the insertion of the loop antennas and pick-up coils. In this study, RF power-balance recovery by slug tuners have been measured by using a low power module of 175MHz RFQ mock-up. The optimal insertion depth of loop antenna was determined to be 3 cm for realizing the appropriate phase differences of TE mode. Under this condition, cylindrical slug tuners were inserted, and S
parameters in each cavity were measured. As a typical result, RF power-balance control less than 20% error can be achieved in case of 
3cm tuner up to 3cm insertion.
Maebara, Sunao; Moriyama, Shinichi; Saigusa, Mikio*; Sugimoto, Masayoshi
JAERI-Research 2005-007, 11 Pages, 2005/03
JAERI-Research-2005-007.pdf:2.59MB
no abstracts in English
Maebara, Sunao; Moriyama, Shinichi; Sugimoto, Masayoshi; Saito, Yuichi*; Saigusa, Mikio*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.904 - 906, 2005/00
The IFMIF is an accelerator-based neutron irradiation facility employing the D-Li stripping reaction. The required beam current of 250 mA is realized by two beam lines of 125mA, and the output energies at injector, RFQ and DTL were designed to be 0.1, 5 and 40 MeV, respectively. The operation frequency of 175MHz was selected to accelerate the large current of 125mA. After an intensive beam simulation, the RFQ with a total length of 12m was designed to keep the minimum emittance growth with the RF injection power of 2.3MW CW. For such a 175MHz RFQ, a design for RF input coupler with loop antenna and co-axial window, supplying RF power shared by 3 
4 ports, was conducted by using MW-Studio code. In order to withstand the voltage exceeding 200kW CW per one loop antenna, the co-axial line of 4 1/16" diameter is necessary, and it is found that the electric field distortion factor less than 1% can be achieved in beam bore only by employing the 4-loop antenna configuration providing the same power for each quadrants.
Yamazaki, Yoshishige
Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.554 - 558, 2004/00
no abstracts in English
Yamazaki, Yoshishige
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), p.1351 - 1353, 2004/00
The J-PARC (Japan Proton Accelerator Research Complex) is under construction in JAERI Tokai site. The beam commissioning will start there by the end of 2006. Prior to this, the front end of the linac was beam-commissioned in 2003 at KEK. The negative hydrogen beam with a peak current of 30 mA was accelerated up to 20 MeV by the first tank of the three DTL's following the 3-MeV RFQ linac. The 324-MHz DTL contains the electro quadrupole magnets with water-cooling channels specially fabricated by means of electroforming and wire-cutting technologies. The construction status of the J-PARC accelerator is also presented.
Maebara, Sunao; Morishita, Takatoshi; Moriyama, Shinichi; Sugimoto, Masayoshi; Imai, Tsuyoshi; Takeuchi, Hiroshi
Proceedings of 28th Linear Accelerator Meeting in Japan, P. 378, 2003/08
no abstracts in English
Kondo, Yasuhiro; Ueno, Akira*; Ikegami, Masanori*; Ikegami, Kiyoshi*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.69 - 71, 2003/08
A 3.115m long, 324MHz, 3MeV radio-frequency quadrupole (RFQ) linac is used as the first RF accelerator of the J-PARC linac. We have performed RFQ simulations to provide a particle distribution for an end-to-end (from the RFQ entrance to the injection point of the rapid cycling synchrotron (RCS)) simulation of the J-PARC linac. Two simulation codes, PARMTEQM and TOUTATIS are used for the RFQ simulations. The simulated emittances show good agreements with the ones measured at the exit of the medium energy beam transport (MEBT).
Yamazaki, Yoshishige
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.43 - 47, 2003/00
no abstracts in English
Maebara, Sunao; Morishita, Takatoshi; Sugimoto, Masayoshi; Imai, Tsuyoshi; Takeuchi, Hiroshi; Sazawa, Shingo*; Saigusa, Mikio*
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.2829 - 2831, 2003/00
It is indispensable to obtain the technical know-how of the IFMIF RFQ design in the development of RFQ system. It is very important to determine the mesh size in analysis code of the RFQ design. The design of 175MHz RFQ mock-up modules has been done by MAFIA code. Based on this design, the 175MHz RFQ mock-up which consists of two end-plate modules and RFQ modules are fabricated for low power tests. The resonant frequencies have been measured in RFQ length of 1.1m and 2.1m.The measured frequencies are in a good agreement with the calculated values within 1MHz when the mesh size is 1/350 of the longitudinal length.
Yamazaki, Yoshishige
Proceedings of 2003 Particle Accelerator Conference (PAC 2003) (CD-ROM), p.576 - 580, 2003/00
The JAERI-KEK Joint Project for the High Intensity Proton Accelerator, now referred to as the J-PARC Project (Japan Proton Accelerator Research Complex), comprises a 400-MeV linac, a 3-GeV, 25-Hz Rapid-Cycling Synchrotron (RCS), and a 50-GeV Main Synchrotron (MR). In contrast to the SNS or the ESS, the J-PARC makes use of the RCS in order to produce MW-class pulsed spallation neutrons rather than a combination of the full-energy linac and the compressor ring.
Sugimoto, Masayoshi
Proceedings of 25th Linear Accelerator Meeting in Japan, p.141 - 143, 2000/07
The International Fusion Materials Irradiation Facility (IFMIF) as the neutron irradiation facility for developing the fusion reactor materials requires a linac accelerating 40 MeV deuteron beam with current of ampere class continuously, and the design of the accelerating module of 125 mA is conducted. For completing the conceptual design study, the design to reduce the cost by employing a staged construction with 3 steps to achieve final goal of 250 mA was performed. As for the linac, the strategy to realize the 50 mA acceleration at first step and to upgrade to 125 mA was conceived. In this year, the existing designs of RFQ, DTL and RF system will be reviewed and major testing items must be defined, to initiate the verification tests for key component technology. This report summarizes the status of each of component design and the related issues to be implemented in the verification tests.
Mizumoto, Motoharu; Kusano, Joichi; Hasegawa, Kazuo; Ouchi, Nobuo; Oguri, Hidetomo; Ichihara, Masahiro; Tomisawa, Tetsuo; Ito, Takashi; Chishiro, Etsuji*; Ikegami, Masanori*; et al.
KEK Proceedings 99-25, p.3 - 5, 2000/02
no abstracts in English
Sugimoto, Masayoshi; Kinsho, Michikazu; Takeuchi, Hiroshi
Proceedings of 20th International Linac Conference, p.651 - 653, 2000/00
no abstracts in English
Hasegawa, Kazuo; Oguri, Hidetomo; Honda, Yoichiro*; Ino, H.*; Mizumoto, Motoharu; Jameson, R. A.*
Proc. of 1st Asian Particle Accelerator Conf. (APAC98), p.71 - 73, 1998/11
no abstracts in English
Akaoka, Nobuo*; Chishiro, Etsuji*; Hasegawa, Kazuo; Honda, Yoichiro*; Ino, H.*; Kaneko, H.*; Kinsho, Michikazu; Kusano, Joichi; Mizumoto, Motoharu; Mukugi, Ken*; et al.
Proceedings of 6th European Particle Accelerator Conference (EPAC98) (CD-ROM), 2 Pages, 1998/09
no abstracts in English
