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ion sourceNamekawa, Yuya; Ueno, Akira; Okoshi, Kiyonori; Oguri, Hidetomo; Ikegami, Kiyoshi*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.845 - 847, 2010/03
The J-PARC H ion source succeeds in producing a beam current of 38 mA without seeding Cs. It satisfies the requirement of the J-PARC 1st stage in which a beam power will be 0.6 MW. However a beam current of more than 60 mA is necessary for the J-PARC 2nd stage in which a beam power will be 1 MW. Therefore, two R&D(research and development)'s are being carried out in order to increase the beam current. One is without seeding Cs and the other is with seeding Cs. In the latter R&D, a beam current of 70 mA is produced with a W-filament and an arc-power of 15 kW. The low arc-power, will be helpful for reducing the Cs consumption rate. The lower Cs consumption rate is necessary for the stabler operation against sparking in high voltage gaps. The practicability of the ion source with seeding Cs is examined by optimizing the filament material and shape, the Cs seeding system including the temperature control of each part of plasma chamber and the plasma confinement magnetic field.
Kojima, Toshiyuki; Takahashi, Hiroki; Sakaki, Hironao; Maebara, Sunao
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.487 - 489, 2010/03
no abstracts in English
Shinto, Katsuhiro; Vermare, C.*; Asahara, Hiroo; Sugimoto, Masayoshi; Garin, P.*; Maebara, Sunao; Takahashi, Hiroki; Sakaki, Hironao; Kojima, Toshiyuki; Ohira, Shigeru; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.668 - 670, 2010/03
Progress of the IFMIF/EVEDA prototype accelerator in fiscal year of 2008 is described. All the sub-systems of the prototype accelerator have started to design, settled the plan of the manufacturing and component tests and fixed the design parameters. As a result of the analysis of planning for the engineering validation of the IFMIF accelerator system, the project duration to be prolonged to the end of 2014 including some months for contingency was approved by the BA Steering Committee. In this article, the design status of each accelerator component, the interface between the accelerator components and the IFMIF/EVEDA Accelerator Building settled in International Fusion Energy Research Centre (IFERC) in Rokkasho and the proposed accelerator commissioning plan for the engineering validation will be presented.
ion sourceOguri, Hidetomo; Ueno, Akira; Ikegami, Kiyoshi*; Namekawa, Yuya; Okoshi, Kiyonori
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.842 - 844, 2010/03
A cesium-free H ion source driven with a LaB
filament is being operated for J-PARC. The beam commissioning of J-PARC accelerators started in November 2006. As of June 2009, there have been 25 beam commissioning or supply runs. In these runs, the ion source has been successfully operated in two different modes. One is a low beam current mode, in which approximately 5 mA is produced. The other is a high beam current mode, in which approximately 30 mA is produced. According to the task of the run, one of the two modes was selected. Since the beam current can be maintained within a few percent errors by tuning the ion source parameter once a day, 24 hours beam operation with an ion source operator only in day time was started in April 2008. The total interruption time during the runs due to the ion source failure is approximately 50 hours as of June 2009. The availability of the ion source is calculated to be 99%. The interruptions were mainly caused by the insufficient lifetime of the filament. By a few modifications on the filament shape administered until August 2007, we succeeded in achieving the lifetime of 2,030 hours, which included 1,250 hours in the low beam current mode and 780 hours in the high beam current mode.
Takahashi, Hiroki; Kojima, Toshiyuki; Sakaki, Hironao; Maebara, Sunao
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.490 - 492, 2010/03
no abstracts in English
Nishimori, Nobuyuki; Nagai, Ryoji; Iijima, Hokuto; Hajima, Ryoichi; Yamamoto, Masahiro*; Muto, Toshiya*; Miyajima, Tsukasa*; Honda, Yosuke*; Kuriki, Masao*; Kuwahara, Makoto*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.872 - 874, 2010/03
no abstracts in English
ion sourceIkegami, Kiyoshi*; Ueno, Akira; Oguri, Hidetomo; Namekawa, Yuya; Okoshi, Kiyonori
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.839 - 841, 2010/03
A cesium-free H ion source driven with a LaB filament is under operation at the Japan Proton Accelerator Research Complex (J-PARC). The ion source succeeded in producing the maximum beam current of 38 mA, which is satisfied with the requirement for the J-PARC initial stage of 36 mA. The operating beam current, however, is within 30-33 mA during the accelerator beam commissioning run because we restrict the maximum arc current to 300 A for a highly stable beam operation. In order to improve the arc power efficiency for the beam current and to examine the possibility to satisfy with the requirement for the J-PARC final goal, we started to survey about the optimal size and shape of the LaB filament by using the H ion source test stand. All the tests were carried out with the same condition such as the arc current (300A), the beam energy and the magnet configuration of the plasma chamber. The beam current of 35.2 mA was extracted using a double spiral LaB filament with a diameter of 29.5 mm and length of 35.5 mm, which is the same dimension as the present J-PARC ion source. By using a smaller one with a diameter of 15 mm and length of 34 mm, the beam current was increased to 41.8 mA. Furthermore, it was increased to 43.4 mA by using a flat triple hairpin shape LaB filament.
Kabumoto, Hiroshi; Takeuchi, Suehiro; Ishizaki, Nobuhiro; Yoshida, Takahiro*; Ishiguro, Takayuki*; Yamaguchi, Kazushi*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1120 - 1122, 2010/03
The JAEA-Tokai tandem accelerator was built for basic science researches with heavy ions. Its superconducting booster was completed in 1994 for increasing the acceleration energy of ions. The booster consists of 40 superconducting acceleration resonators and 10 cryostats. Every resonator is a coaxial quarter wave resonator (QWR) of which frequency is 129.8MHz, and optimum beam velocity is 10% of the light velocity. When it was built, the acceleration field gradients of superconducting resonators were 5.0MV/m at RF power input of 4W on their average. The performance decrease little by little, and it become 4.0MV/m now. Some of the resonators generate X-rays from a low electric field. A field emission will be occurred from small contaminations accumulated on the surfaces of niobium. We examined the high pressure water jet rinsing (HPWR) to re-recondition the superconducting booster. The HPWR is the technology of removing small contaminations on resonator surfaces, and very effective for the improvement of acceleration field gradients. The acceleration field gradients of 20 on-line resonators were improved from 4.4MV to 5.7MV on their average.
Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.897 - 899, 2010/03
no abstracts in English
Okumura, Susumu; Miyawaki, Nobumasa; Yuyama, Takahiro; Ishizaka, Tomohisa; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Ishibori, Ikuo; Yuri, Yosuke; Nara, Takayuki; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.572 - 574, 2010/03
High-frequency change of beams accelerated for users is required at the JAEA AVF cyclotron, since the irradiation time is short in most cases and a large variety of beams is used. The ratio of the beam changing time to the whole operation time is not negligible and the offering machine time for users is half the required one. We are developing a technique for reducing the changing time of the magnetic field of the cyclotron, which dominates the beam changing time. Since a precise and stable magnetic field is required for acceleration in the cyclotron, especially for advanced beam applications, such as microbeam production, a magnetic field measurement system with a nuclear magnetic resonance (NMR) magnetometer was developed to monitor a wide range of magnetic field for acceleration of variety of beams in the JAEA AVF cyclotron.
Matsuda, Makoto; Asozu, Takuhiro; Kutsukake, Kenichi; Nakanoya, Takamitsu; Hanashima, Susumu; Takeuchi, Suehiro
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.827 - 829, 2010/03
no abstracts in English
Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Omori, Chihiro*; Nomura, Masahiro; Schnase, A.; Toda, Makoto*; Suzuki, Hiromitsu; Shimada, Taihei; Hara, Keigo*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.366 - 368, 2010/03
For stable acceleration of the high intensity proton beams, increasing the bunching factor by the longitudinal painting is essentially important to reduce the space-charge tune shift. The momentum offset injection method and applying the second harmonic RF are employed for the longitudinal painting in the J-PARC RCS. We employ wide band magnetic alloy (MA) cavities to realize the dual-harmonic operation, in which each cavity is driven by the superposition of the fundamental and the second harmonic RF signals. By the dual-harmonic operation we can generate the large amplitude second harmonic RF without extra cavities for the second harmonic. We report the beam test results of the longitudinal painting.
Schnase, A.; Omori, Chihiro*; Tamura, Fumihiko; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Shimada, Taihei; Suzuki, Hiromitsu; Takagi, Akira*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1077 - 1079, 2010/03
Yoshimoto, Masahiro; Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Omori, Chihiro*; Hayashi, Naoki; Kawase, Masato; Watanabe, Kazuhiko*; Yoshikawa, Muneyoshi*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.737 - 740, 2010/03
The longitudinal phase space tomography, which was evolved to retrieve the two-dimensional beam distribution in the longitudinal phase space with computer tomography algorithms, is very useful diagnostic tool in the accelerator domain. The simple reconstruction tool was developed for the J-PARC RCS and MR with the convolution back projection method for the beam storage mode. On the assumption that the longitudinal profiles should not be disturbed for one period of the synchrotron oscillation, such two-dimensional profiles can be reconstructed easily from one-dimensional bunch beam profiles, which are measured for every turn by the wall current monitor.
Miyawaki, Nobumasa; Okumura, Susumu; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.183 - 185, 2010/03
The characteristics of beam phase (BP) for three of acceleration harmonic modes (H=1, 2, 3) were investigated in the central region of the JAEA AVF cyclotron. Experiments were made to clarify relations of BP to the spatial displacements of ion beam orbits in the radial direction at the phase defining slit (PDS), and also to the initial condition of BP at the exit of the inflector defined by the phase shift of the beam bunching (BB). Some correlation of the BPs to both of the position of PDS and the phase shift of BB were observed in the case of H=1, but no correlation was found in the case of H=2. And in the case of H=3, only correlations of the intensity of the beam phase to them were observed with larger phase width than that in case of H=2. It is expected that optimization of the injection system and the central region of the cyclotron can be made according to these characteristics of BP depending on H, so as to obtain higher transmission of high quality ion beams.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1047 - 1049, 2010/03
The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The basic concept of the engineering design is the simplicity and the effective vacuum pumping aiming at the stable operation. A 3m long cavity is divided into 3 modules longitudinally. A numerical control machining with ball-end mill is chosen for a vane machining. Four vanes are vacuum brazed each other after machining. Each modules are aligned on the platform using a linear motion guide. A basic design of the key components on machining and brazing are described in this proceeding.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Matsumoto, Hiroshi*; Hori, Yoichiro*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1050 - 1052, 2010/03
The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision to RCS was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The RF simulation is underway for the design of this backup RFQ. A basic estimation on the key components on RF properties such as a tuner, a dipole stabilizer, and a local field correction at the vacuum port are described in this proceeding.
Hasegawa, Kazuo; Morishita, Takatoshi; Kondo, Yasuhiro; Oguri, Hidetomo; Kobayashi, Tetsuya; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Kawamata, Hiroshi*; Hori, Yoichiro*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.693 - 695, 2010/03
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a beam from the ion source to the DTL. The beam test of the linac was started in November 2006 and 181 MeV beam was successfully accelerated in January 2007. Since then, the linac has been delivered beams for commissioning of the linac itself, downstream accelerators and facilities. Trip rates of the RFQ, however, suddenly increased in Autumn 2008, and we are suffering from this issue for user run operation. We tried to recover by tender conditioning, modification of RF control, improvement of vacuum and so on. We manage to have beam operation. In this report, we describe the status of the RFQ.
Sato, Susumu; Miura, Akihiko; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Sako, Hiroyuki; Morishita, Takatoshi; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Kobayashi, Tetsuya
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.298 - 300, 2010/03
no abstracts in English
Kondo, Yasuhiro; Hasegawa, Kazuo; Morishita, Takatoshi; Naito, Fujio*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1038 - 1040, 2010/03
Now, J-PARC accelerator developing new RFQ for stable operation. The specification of this new RFQ is same as the now operating RFQ. Resonant frequency is 324MHz, injection energy is 50keV, extraction energy is 3MeV, RF duty is 3%. However, we adopt Dipole Stabilizing Rods (DSR's) instead of Pi-mode Stabilizing Loops (PISL's), which are potential cause of discharging. And assemble method will be brazing to increase reliability. As for the RF couplers, to simplify the structure, we will change to one-feed from two-feed. Maximum peak power to feed is 400kW and duty is 3%. In this paper, the design of the RF coupler for the new J-PARC RFQ is described.
