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Takayanagi, Tomohiro; Ono, Ayato; Ueno, Tomoaki*; Horino, Koki*; Togashi, Tomohito; Yamamoto, Kazami; Kinsho, Michikazu; Koizumi, Isao*; Kawamata, Shunsuke*
JPS Conference Proceedings (Internet), 33, p.011020_1 - 011020_6, 2021/03
We are developing a new kicker power supply for J-PARC 3-GeV RCS (Rapid-Cycling Synchrotron) using the next generation power semiconductor SiC-MOSFET with high withstand voltage, low loss, and superior high frequency characteristics. The three major circuits adopted for the RCS kicker power supply, the thyratron switch, the PFN circuit of coaxial cable type, and the end clipper for reflection wave absorption, has been realized with a single modular circuit board based on the LTD circuit. The new kicker power supply realizes stable operation, miniaturization and energy saving by using power semiconductors. The required high voltage can be output by stacking the 800V/2kA modular circuit board in series. The details of circuit design and the results of achieving an output of half 20kV/2kA against the target specification of 40kV/2kA are presented here.
Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.
JAEA-Review 2016-008, 98 Pages, 2016/07
JAEA-Review-2016-008.pdf:11.73MB
Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.
Oguri, Hidetomo; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Yamazaki, Saishun; Takagi, Akira*; Koizumi, Isao; Ueno, Akira
JPS Conference Proceedings (Internet), 8, p.011009_1 - 011009_6, 2015/09
Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.
Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12
Times Cited Count：8 Percentile：43.61(Physics, Nuclear)We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.
Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
ion source for the J-PARCKoizumi, Isao; Ueno, Akira; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.920 - 923, 2014/06
In order to satisfy the J-PARC (Japan Proton Accelerator Research Complex) 2nd stage requirements the J-PARC rf-driven H ion source is under development. The source plasma is produced by an about 50 W CW 30 MHz-rf and an about 40 kW pulsed 2 MHz-rf. The Cs is installed into the plasma chamber by opening the Cs-valve between the plasma chamber and the Cs oven, which is heated to 200
240 
C. The H ion beam current is maximized by optimizing the Cs quantity depending upon the Cs-valve opening time, the PE temperature depending upon the flow rate of the air through the PE cooling plate, the AMFC by the AMFC coil current, and so on. The experimental results using the plasma chamber made of copper, which satisfied the above requirements, were reported last year. The experimental results using the plasma chamber made of stainless steel are presented in this paper. The observed several interesting differences between the two plasma chambers are also presented.
Okoshi, Kiyonori; Ikegami, Kiyoshi*; Koizumi, Isao; Ueno, Akira; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.946 - 949, 2014/06
A J-PARC ion source driven with a LaB6 filament is being operated without any serious trouble since the restoration from the earthquake. The H ion current from the source is routinely restricted 19 mA for the filament lifetime. In order to increase the beam power at the linac beam operation, the beam current from the ion source was increased to 22 mA. At this operation, the filament lifetime was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after 10 h from the steep current reduction, the beam operation was restarted 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV synchrotron, the ion source was operated at 30 mA for 8 days.
ion sourceUeno, Akira; Koizumi, Isao; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Yamazaki, Saishun; Oguri, Hidetomo
Review of Scientific Instruments, 85(2), p.02B133_1 - 02B133_5, 2014/02
Times Cited Count：6 Percentile：26.12(Instruments & Instrumentation)no abstracts in English
ion source for the J-PARCYamazaki, Saishun; Ueno, Akira; Namekawa, Yuya*; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Takagi, Akira*; Koizumi, Isao; Oguri, Hidetomo
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.260 - 264, 2013/08
A cesium (Cs) seeded RF-driven H ion source using an internal-antenna developed at the SNS (Spallation Neutron Source) is under development for the J-PARC (Japan Proton Accelerator Research Complex). The axial magnetic field optimization by using an axial magnetic field compensation (AMFC) coil significantly enhances the H ion beam by typically 10%. An H ion beam with a flat top duty factor of 2.5% (1 ms 
25 Hz) of 77 mA, whose about 90% (corresponding to about 70 mA) of emittance of each direction is within 1.5 
mm
mrad, is successfully extracted. During a demonstration operation over 100-hours, an H ion beam over 66 mA was successfully produced with a relatively low RF power of about 40 kW by seeding Cs for 4-minutes a day.
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Koizumi, Isao; Takagi, Akira*; Namekawa, Yuya*; Yamazaki, Saishun; Ueno, Akira
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1081 - 1083, 2013/08
no abstracts in English
Oguri, Hidetomo; Ikegami, Kiyoshi*; Okoshi, Kiyonori; Koizumi, Isao; Namekawa, Yuya*; Ueno, Akira; Takagi, Akira*; Yamazaki, Saishun
AIP Conference Proceedings 1515, p.379 - 385, 2013/02
Times Cited Count：4 Percentile：81.46(Physics, Applied)The J-PARC was extensively damaged by the earthquake in March 2011. The ion source had some damages such as dew condensation on the ion source surface due to the flooding in the accelerator tunnel, vacuum leakage due to the breaking of the viewing port and vacuum pump failure due to the strong quake. The restoration work was accomplished on schedule, and the linac beam operation was restarted in December 9th. The ion source supplies the beam to the accelerator without serious aftereffects of the earthquake. Availability of the ion source is one of the important issues because it is directly related to the operation time of the J-PARC. To evaluate the lifetime of the present ion source, we started 2 months beam operation. The results of recent four beam runs show the ion source is capable of continuous operation for approximately 1,200 hours with the beam current of 17 mA. For another attempt to enhance the ion source availability, we tried to decrease the time for maintenance to replace consumable elements. By unitizing the replacement elements and keeping them under the vacuum condition until just before the installing, the maintenance is completed within 24 hours without any beam performance degradation of the ion source.
ion sourceUeno, Akira; Namekawa, Yuya*; Yamazaki, Saishun; Okoshi, Kiyonori; Koizumi, Isao; Ikegami, Kiyoshi*; Takagi, Akira*; Oguri, Hidetomo
AIP Conference Proceedings 1515, p.409 - 416, 2013/00
Times Cited Count：7 Percentile：90.09(Physics, Applied)In order to satisfy the J-PARC second stage requirements a cesiated RF-driven H ion source using a internal-antenna developed at the Spallation Neutron Source (SNS) was developed. As similar as the SNS ion source, two matching networks for pulsed high-temperature 2MHz-RF plasma and CW low-temperature 30MHz-RF plasma are used. Each of them is composed of two vacuum variable condensers (VVCs). In order to supply pulsed 60kW - 2MHz-RF power from the power supply (PS) on the ground level, a one-turn isolation transformer using FINEMET cores is installed between the PS and the J-PARC ion source. Up to 46kW of pulsed 2MHz-RF power is successfully input to the plasma stably and with almost no reflected power.
ion source for the J-PARCUeno, Akira; Namekawa, Yuya*; Yamazaki, Saishun; Okoshi, Kiyonori; Koizumi, Isao; Ikegami, Kiyoshi*; Takagi, Akira*; Oguri, Hidetomo
AIP Conference Proceedings 1515, p.331 - 340, 2013/00
Times Cited Count：9 Percentile：92.79(Physics, Applied)In order to satisfy the J-PARC second stage requirements of an H ion beam current of 60 mA within normalized emittances of 1.5 -mm-mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500 micros 25 Hz) and a life-time of more than 50 days, a cesiated RF-driven H ion source using a internal-antenna developed at the Spallation Neutron Source (SNS) was developed. The J-PARC RF-driven source was manufactured by modifying the J-PARC cesiated H ion source driven with two tungsten (W) filaments, which successfully produced a 76.2 mA H ion beam current but had an insufficient life time of about 500 hours. It successfully produced a 77.5 mA H ion beam with a flat top duty factor of 2% (800 micros 25 Hz) whose 87.7% (68 mA) and 89.1% (69 mA) are within horizontal and vertical 1.5 -mm-mrad emittances, respectively. It also had successfully produced more than 60 mA within 1.5 -mm-mrad emittances H ion beam continuously over 100 hours.
Koizumi, Isao*; Suganuma, Kazuaki
JAEA-Testing 2011-002, 223 Pages, 2011/06
JAEA-Testing-2011-002.pdf:8.22MB
3GeV synchrotron accelerator building was constructed by reinforced concrete, which is the acceleration facility at J-PARC (Japan Proton Accelerator Research Complex). 3GeV synchrotron accelerator building was built in 2005 and beam operation had been performed successfully run since 2008. I had been inspecting of each instruments since beam operation had run. In 2011, inspection list had created and carried out as inspected because of the floor crack is outstanding. This report arranges the inspection of floor crack, inspection records and repair procedures of the 3GeV synchrotron accelerator building.
Koizumi, Masumichi; ; Kaneko, Hiromitsu; Kishimoto, Yoichiro; Kanamori, Masashi; Ojima, Hisao; ;
PNC TN842 83-05, 49 Pages, 1983/10
None
Onoda, Shinobu; Yamamoto, Takashi; Abe, Hiroshi; Hanaya, Hiroaki; Oshima, Takeshi; Taniguchi, Takashi*; Teraji, Tokuyuki*; Watanabe, Kenji*; Koizumi, Satoshi*; Kanda, Hisao*; et al.
no journal, ,
no abstracts in English
Yamamoto, Takashi; Onoda, Shinobu; Oshima, Takeshi; Naydenov, B.*; Dolde, F.*; Fedder, H.*; Honert, J.*; Jelezko, F.*; Wrachtrup, J.*; Teraji, Tokuyuki*; et al.
no journal, ,
no abstracts in English
