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Yamazaki, Yoshio; Hirano, Koichiro*; Fukuda, Satoshi*; Takano, Mikio*; Araki, Sakae*; Terunuma, Nobuhiro*; Urakawa, Junji*
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), 0 Pages, 2004/07
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Sawamura, Masaru; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004) (CD-ROM), p.1723 - 1725, 2004/07
After the success of energy recovery linac (ERL) for the superconducting free-electron laser (FEL) in the Japan Atomic Energy Research Institute (JAERI), the JAERI ERL-FEL has been upgrading for high-power and long-pulse operation. The new RF sources of CW mode for higher power for non-energy-recovery parts have been installed and tested for long-pulse operation. The properties of the superconducting linac required for the long-pulse operation were measured such as pressure in the cryomodule, vibration of frequency and piezo tuner response. The RF control systems have been also upgraded to reduce the fluctuation to less than 0.1% for amplitude and 0.1 deg for phase.
Kako, Eiji*; Noguchi, Shuichi*; Ouchi, Norihito*; Shishido, Toshio*; Akaoka, Nobuo*; Kobayashi, Hideki*; Ouchi, Nobuo; Ueno, Tomoaki*; Hara, Hiroshi*; Matsuoka, Masanori*; et al.
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004) (CD-ROM), p.1042 - 1044, 2004/07
no abstracts in English
Ouchi, Norihito*; Kako, Eiji*; Noguchi, Shuichi*; Shishido, Toshio*; Tsuchiya, Kiyosumi*; Akaoka, Nobuo*; Kobayashi, Hideki*; Ouchi, Nobuo; Ueno, Tomoaki*; Hara, Hiroshi*; et al.
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), p.1033 - 1035, 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.
Okawa, Tomohiro*; Ikegami, Masanori*
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), p.1342 - 1344, 2004/00
The accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC, consist of a 180-MeV linac, a 3-GeV RCS (Rapid Cycling Synchrotorn), and a 50-GeV MR (Main Ring). L3BT is a beam transport line from the linac to the RCS. To meet the requirement for the beam loss minimization, the L3BT does not only connect the linac to the 3GeV RCS, but also modifies the linac beam to be acceptable for the RCS. The required beam parameters at the injection point of the RCS are momentum spread 
0.1
and transverse emittance 4
mm
mrad. To achieve these beam qualities, the L3BT should have following functions: momentum compaction, transverse halo scraping and beam diagnostics. In this paper, results of the design and beam simulation of the L3BT are presented.
Irie, Yoshiro
Proceedings of 9th European Particle Accelerator Conference (EPAC 2004), p.113 - 117, 2004/00
The MW proton source using rapid cycling synchrotron (RCS) has many challenging aspects, such as (1) large aperture magnets and much higher RF voltages per turn due to a low energy injection and a large and rapid swing of the magnetic field, (2) field tracking between many magnet-families under slightly saturated conditions, (3) RF trapping with fundamental and higher harmonic cavities, (4) H- charge stripping foil, (5) large acceptance injection and extraction straights, (6) beam loss collection, and (7) beam instabilities. These are discussed in details mainly on the basis of the J-PARC 3GeV RCS, which is under construction in Japan. Issues (3) to (7) are common with another scheme of MW spallation neutron source, i.e. full-energy linac + accumulator ring. Comparisons with the SNS design in the US are then made. Reliability/availability of these machines is very important theme which finally determines the successful operations. From the experiences in the existing machines, we will discuss the factors necessary toward the better performance.