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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.
Hasegawa, Kazuo
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.220 - 224, 2005/00
no abstracts in English
Hotchi, Hideaki; Noda, Fumiaki*; Tani, Norio; Kishiro, Junichi*; Machida, Shinji*; Molodojentsev, A. Y.*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.916 - 918, 2005/00
no abstracts in English
Shobuda, Yoshihiro; Chin, Y. H.*; Omi, Kazuhito*; Toyama, Takeshi*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.1898 - 1900, 2005/00
At 3GeV RCS(Rapid Cycle Synchrotron) in J-PARC, the ceramic chamber is adopted to aviod the excess eddy current. This ceramic chamber is surrounded by Cu-stripes to supress the leak field caused by the beam. The inner surface of the chamber is coated with TiN to suppress the secondary electron emission. In order to discuss the beam instability, we have to calculate the impedance for this chamber. Previously, the impedance was calculated by replacing the Cu-stripes to the conducting beam pipe. In this paper we deal with Cu-stripes realistically, and compare the results with the previous results. The resistivity of Cu-stripes and the TiN are also considered.
Saha, P. K.; Noda, Fumiaki*; Irie, Yoshiro; Hotchi, Hideaki; Takayanagi, Tomohiro; Hayashi, Naoki; Machida, Shinji*; Sakai, Izumi*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.3739 - 3741, 2005/00
The RCS(rapid cycling synchrotron) of J-PARC(Japan proton accelerator research complex) acts as an injector to the main ring as well as a high-power beam for the spallation neutron source at a repetition rate of 25 Hz, where at present the injection and the extraction beam energy are chosen to be 0.181 GeV and 3.0 GeV, respectively. The present work concerns on the present design and calculations for the injection-dump line of the RCS, which includes, (1) an accurate aperture list of all elements taking into account a wide range of the betatron tune, effect of changing injection modes, multiple trajectories of different particles after the charge-exchange foil(like H0 from the H- and H- beam itself)and (2) an accurate estimation of the uncontrolled beam losses especially from the H0-excited states, multiple coulomb scattering at the charge-exchange foil and also the lorentz stripping loss at the septum magnets so as to optimize them concerning mainly the radiation issues as well as for the hands-on maintenance.
Noda, Fumiaki*; Hotchi, Hideaki; Saha, P. K.; Shobuda, Yoshihiro; Yamamoto, Kazami; Hayashi, Naoki; Kishiro, Junichi; Machida, Shinji*; Molodojentsev, A. Y.*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2759 - 2761, 2005/00
no abstracts in English
Hayashi, Naoki; Hiroki, Seiji; Kishiro, Junichi*; Teruyama, Yuzo*; Toyokawa, Ryoji; Arakawa, Dai*; Lee, S.*; Miura, Takako*; Toyama, Takeshi*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.299 - 301, 2005/00
Development of the beam diagnostics system for the J-PARC (Japan Proton Accelerator Research Complex) Rapid-Cycling Synchrotron is described. The system consists of Beam Position Monitor (BPM), Beam Loss Monitor (BLM), Current monitors (DCCT, SCT, MCT, FCT, WCM), Tune meter system, 324MHz-BPM, Profile monitor, and Halo monitor. BPM electrode is electro-static type and its electronics is designed for both COD and turn-by-turn measurements. Five current monitors have different time constants in order to cover wide frequency range. The tune meter is consisted of RFKO and the beam pick-up electrode. For the continuous injected beam monitoring, 324MHz-BPM detects Linac frequency. Two types of profile monitor are multi-wire for low intensity tuning and the residual gas monitor for non-destructive measurement.
Kamiya, Junichiro; Takayanagi, Tomohiro; Kawakubo, Toshimichi*; Murasugi, Shigeru*; Nakamura, Eiji*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.1009 - 1011, 2005/00
The kicker magnets are installed in the vacuum chamber at the extraction section of the RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex) facility. They kick the 3GeV proton beam to the extraction septum magnets followed by a downstream beam transport line. The RCS is designed to achieve the 1MW beam power with minimum loss. Therefore, the kicker is required to have a wide aperture, UHV (ultra-high vacuum) in its chamber, and uniformity of magnetic field. The wide aperture requires large exciting current and the use environment of the thyratron is very tough. Therefore aging run was found out to be needed. And the uniformity of the magnetic field was improved by changing length of the conductors. In order to achieve the UHV, we succeeded in reducing outgas from components of the magnet. In this paper, we will introduce the specification of the extraction kicker system in the RCS, and report countermeasure against the technical challenge described above.
Okawa, Tomohiro*; Ikegami, Masanori*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.3091 - 3093, 2005/00
L3BT is beam transportation line from the linac to the 3-GeV RCS which is the part of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. In this paper, especially results of the beam simulation of the injection section of the L3BT are presented. The injection section is necessary for a successful adjustment to the transported beam to the required parameters for ring injection. The matching of beams envelopes and dispersion function for space charge dominative beams are also discussed.
Morishita, Takatoshi; Ao, Hiroyuki; Ito, Takashi; Ueno, Akira; Hasegawa, Kazuo; Ikegami, Masanori*; Kubota, Chikashi*; Naito, Fujio*; Takasaki, Eiichi*; Tanaka, Hirokazu*; et al.
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2851 - 2853, 2005/00
In J-PARC linac, a precise alignment of accelerator components is essential for high quality beam acceleration. Markings have been placed on the floor, which act as a reference for the initial alignment at the installation. For a straight line alignment, the wire position sensor is placed on the offset position with respect to the beam center by a target holder. The hydrostatic levering system is used for watching the floor elevation over the long period.
Ao, Hiroyuki; Morishita, Takatoshi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Paramonov, V.*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2684 - 2686, 2005/00
J-PARC Linac starts with 180-MeV SDTL temporary, and it is upgraded to 400-MeV with 21 ACS (Annular Coupled Structure) modules and two ACS bunchers and two debunchers. First buncher module is under fabrication, and second buncher and a few accelerating modules are also planed until FY2006. The first ACS module consists of two 5-cell ACS tanks and a 5-cell bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.
Sato, Susumu; Tomisawa, Tetsuo; Akikawa, Hisashi; Ueno, Akira; Lee, S.*; Igarashi, Zenei*; Ikegami, Masanori*; Toyama, Takeshi*; Kamikubota, Norihiko*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2777 - 2779, 2005/00
The J-PARC LINAC requires for fine control of beam position to minimize beam loss. So that BPMs need to be calibrated with the accuracy of about a hundred micro-meters. The accuracy of BPMs are calibrated with the calibration tool and real beam. In this paper, details of these developments around BPMs are to be reported.
Kinsho, Michikazu; Ogiwara, Norio; Saito, Yoshio*; Kabeya, Zenzaburo*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2604 - 2606, 2005/00
It was success to develop alumina ceramics vacuum ducts for the 3GeV-RCS of J-PARC at JAERI. There are two types of alumina ceramics vacuum ducts needed, one being 1.5m-long duct with a circular cross section for use in the quadrupole magnet, the other being 3.5m-long and bending 15 degrees, with a race-track cross section for use in the dipole magnet. These ducts could be manufactured by joining several duct segments of 0.5-0.8 m in length by brazing. The alumina ceramics ducts have copper stripes on the outside surface of the ducts to reduce the duct impedance. In order to reduce emission of secondary electrons when protons or electrons strike the surface, TiN film is coated on the inside surface of the ducts.
-ray irradiation experiments of collimator key components for the 3GeV-RCS of J-PARCKinsho, Michikazu; Ogiwara, Norio; Masukawa, Fumihiro; Takeda, Osamu; Yamamoto, Kazami; Kusano, Joichi
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.1309 - 1311, 2005/00
It was success to develop the radiation resistant components using for beam collimator. Turbo molecular pump could be operated more than 15 MGy of ray irradiation dose. Stepping motor developed at JAERI could be operated with good performance in the ray dose of more than 70 MGy. PEEK sheathed cables and connector have kept good performance during ray irradiation more than the dose of 10 MGy. It was cleared that the function of the heat pipe disappeared at 30 kGy ray irradiation dose.
Takayanagi, Tomohiro; Irie, Yoshiro; Kamiya, Junichiro; Watanabe, Masao; Watanabe, Yasuhiro; Ueno, Tomoaki*; Noda, Fumiaki*; Saha, P. K.; Sakai, Izumi*; Kawakubo, Toshimichi*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.1048 - 1050, 2005/00
The pulse bending magnets for the injection system of the 3-GeV RCS in J-PARC has been designed. The injection system consists of the pulsed bending magnets, which are four horizontal bending magnets (shift bump) and four horizontal painting magnets (h-paint bump) for the injection bump orbit, and two vertical painting magnets (v-paint magnet). The injection beam energy and the extraction beam power are 400 MeV and 1 MW at 25 Hz repetition rate, respectively. The acceptance to include the injection beam, the painting beam and the circulating beam at the shift bump points is a 388 mm wide and a 242 mm high. The shift bump has been designed using a 3D magnetic analysis code, which accomplished less than 0.4 % field deviation under 0.26 T excitation level.
Kako, Eiji*; Noguchi, Shuichi*; Ouchi, Norihito*; Shishido, Toshio*; Tsuchiya, Kiyosumi*; Akaoka, Nobuo*; Chishiro, Etsuji; Hori, Toshihiko; Kobayashi, Hideki*; Nakata, Morihiro*; et al.
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.3579 - 3581, 2005/00
no abstracts in English