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Yoshimoto, Masahiro; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Sugai, Isao*; Irie, Yoshiro*
Journal of Radioanalytical and Nuclear Chemistry, 305(3), p.865 - 873, 2015/09
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)In the 3-GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC), we adopted thick Hybrid type Boron-doped Carbon (HBC) stripper foil for the multi-turn H
charge-exchange injection. The HBC foil has a great advantage of its longer lifetime against high irradiation. Until now, deformation of the HBC foil is observed, but has not broken during 6 months user operation. However there are high residual dose in the RCS injection area. The highest residual dose is observed at the downstream of titanium chamber flange where the stripper foil is placed. The residual dose was increased with the LINAC energy upgrade from 181 MeV to 400 MeV. It shows that secondary neutrons and protons generated by nuclear reactions in the stripper foil at high energy and high power beam irradiation are the major sources for high residual dose at the injection area. The radio-activation of the stripper foil itself is an intrinsic problem and thus maintenance scenario of the stripper foil at the highly-dosed environment is one of the most important issues for the high intensity accelerators. In the J-PARC RCS, the foil exchange devices were improved according to the new maintenance scenario which aims to keep radiation exposure to staffs as low as possible and to reduce the risk of the radioactive foils break up or disperse. In addition, various analyses of the irradiated stripper foils can be carried out if the foils can be retrieved from the tunnel without breaking.
Yoshimoto, Masahiro; Saha, P. K.; Yamazaki, Yoshio; Kawase, Masato; Saeki, Riuji; Hayashi, Naoki; Yamamoto, Kazami; Hotchi, Hideaki; Ishiyama, Tatsuya; Kinsho, Michikazu; et al.
Journal of Physics; Conference Series, 417, p.012073_1 - 012073_6, 2013/03
Times Cited Count：4 Percentile：75.73(Materials Science, Coatings & Films)The HBC foil are installed in the J-PARC RCS for the charge-exchange H beam injection. In order to examine the characteristics of the HBC foils, beam studies for the HBC foil were carried out from the viewpoint of foil's life time and the beam survival rate due to foils. According to the compromise between charge-exchange efficiency and foil scattering beam loss, we optimized the foils thickness for user operation. The long-term observation during the user operation as well as the HBC foil endurance test for its life time evaluation was carried out. Even after one year was operation, there was no deterioration of the stripping foil.
C targets on Au backingsSugai, Isao*; Takeda, Yasuhiro*; Kawakami, Hirokane*; Ota, Naoto*; Makii, Hiroyuki; Miyatake, Hiroari*
Nuclear Instruments and Methods in Physics Research A, 655(1), p.24 - 33, 2011/11
Times Cited Count：3 Percentile：26.67(Instruments & Instrumentation)Saha, P. K.; Yoshimoto, Masahiro; Hatakeyama, Shuichiro; Hotchi, Hideaki; Harada, Hiroyuki; Yamazaki, Yoshio; Kinsho, Michikazu; Irie, Yoshiro*; Sugai, Isao*
Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.3511 - 3513, 2011/09
Yamazaki, Yoshio; Yoshimoto, Masahiro; Takeda, Osamu; Kinsho, Michikazu; Sugai, Isao*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3924 - 3926, 2010/05
J-PARC requires thick carbon stripper foils to strip electrons from the H
beam supplied by the linac before injection into the Rapid Cycling Synchrotron (RCS). Foil thickness is about 200 
g/cm
corresponding to conversion efficiency of 99.7% from the primary H beams of 181 MeV energy to H
. For this purpose, we have successfully developed hybrid type thick boron-doped carbon (HBC) stripper foils, which showed a drastic improvement not only with respect to the lifetime, but also with respect to thickness reduction and shrinkage at high temperature during long beam irradiation. We started to study carbon stripper foils microscopically why carbon foils have considerable endurance for the beam impact by boron-doped. At first, we made a comparison between nominal carbon and HBC by the electric microscope and ion-induced analysis.
Yoshimoto, Masahiro; Yamazaki, Yoshio; Hayashi, Naoki; Yamamoto, Kazami; Saeki, Riuji; Hotchi, Hideaki; Saha, P. K.; Harada, Hiroyuki; Kawase, Masato; Ishiyama, Tatsuya; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3927 - 3929, 2010/05
The (
)ybrid type thick (
)oron-doped (
)arbon (HBC) stripping foils are installed and used for the beam injection at the 3GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex). Up to now, the performance deterioration of the stripping foils can not be seen after the long beam irradiation for the 120kW user operation and 300kW high power beam demonstration at the RCS. In order to examine the characteristic of the HBC foils, various beam studies were carried out. The beam-irradiated spot at the foil was measured by scanning the foil setting position, the charge exchange efficiency was evaluated with various thickness foils, and the effect of the SiC fibers supporting the foil mounting was checked with different mounting foils. Beam study results obtained with using the HBC foils will be presented. In addition, the trends of outgas from the stripping foils and the deformations of the foils during the beam irradiation will be reported.
Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Yoshimoto, Masahiro; Yamamoto, Kazami; Yamazaki, Yoshio; Sugai, Isao*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3921 - 3923, 2010/05
The beam loss caused by the nuclear scattering together with the multiple Coulomb scattering at the stripping foil is one main concern of the uncontrolled beam losses in RCS of the J-PARC. In order to have a realistic understanding, a systematic study with both experiment and simulation has been carried out recently. A total of seven targets with different thicknesses were used and the measured beam losses were found to be consistent with the simulation. Such a realistic understanding becomes very useful in order to optimized the size and thickness of the stripping foil in connection with the RCS power upgrade scenario not only with the present injection beam energy of 181 MeV but also for the near future upgrade with 400 MeV.
Be halo nucleus from 
Bi at coulomb barrierMazzocco, M.*; Signorini, C.*; Romoli, M.*; De Francesco, A.*; Di Pietro, M.*; Vardaci, E.*; Yoshida, Koichi*; Yoshida, Atsushi*; Bonetti, R.*; De Rosa, A.*; et al.
European Physical Journal A, 28(3), p.295 - 299, 2006/06
Times Cited Count：46 Percentile：90.03(Physics, Nuclear)The scattering of the radioactive, weakly bound, halo nucleus Be from Bi has been studied at 40 MeV. The measurement performed with a low-intensity and a large-emittance secondary beam could be made using an extremely compact, large solid angle (
2
sr) detecting set-up, based on 8 highly segmented Si telescopes. The 
Be scattering angular distributions, as well as their relative reaction cross-sections, resulted to be rather similar. This may suggest that at Coulomb barrier energies the halo structure and the small weakly binding energy of the Be projectile have no big influence on the reaction dynamics.
Kuramochi, Masaya*; Kinsho, Michikazu; Irie, Yoshiro*; Sugai, Isao*; Igarashi, Susumu*; Arakida, Yoshio*; Takeda, Yasuhiro*
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.637 - 639, 2003/00
Three charge-exchange foils are used in J-PARC 3GeV Synchrotron(RCS). One is used for changing H to H
by stripping electrons, and the others are used for changing H
and H to H which are failed to strip at the first foil. In this paper, we will describe the temperature distribution at the charge-exchange foils calculated by a simulation code 'ANSYS' where the particle distribution is based on a particle tracking code 'ACCSIM'.
Maekawa, Fujio; Kasugai, Yoshimi; Konno, Chikara; Murata, Isao*; Kokooo*; Wada, Masayuki*; Oyama, Yukio; Ikeda, Yujiro; Takahashi, Akito*
Journal of Nuclear Science and Technology, 36(3), p.242 - 249, 1999/03
Times Cited Count：7 Percentile：49.75(Nuclear Science & Technology)no abstracts in English
Maekawa, Fujio; Kasugai, Yoshimi; Konno, Chikara; Wada, Masayuki*; Oyama, Yukio; Ikeda, Yujiro; R.Johnson*; E.T.Cheng*; M.Pillon*; Murata, Isao*; et al.
Fusion Technology, 34(3), p.1018 - 1022, 1998/11
no abstracts in English
Yoshimoto, Masahiro; Yamazaki, Yoshio; Saha, P. K.; Kinsho, Michikazu; Yamamoto, Shunya; Kawaguchi, Kazuhiro*; Sugai, Isao*; Irie, Yoshiro*
no journal, ,
A stripper foil plays an important role for charge-exchange multi-turn injection in high intensity accelerators like the RCS of J-PARC. In order to optimize the foil thickness, the stripping efficiency is obtained by using beam for various thicknesses of the foils. The RCS has three stripper foils. By using a proper combination of three foils, the total H beam, the H and the H beam can be measured separately. As for determining an accurate stripping efficiency, it is very important to know an actual foil thickness. For that purpose, we employed several other methods to measure the foil thickness. The simplest method is the weighing of the foil. Further more accurate methods with the 
particle thickness gauge or the RBS are also adopted. In addition, the cross section of the foil is observed and the thickness is measured directly with the SEM. Through such direct measurements of the foil thickness, an accurate stripping efficiency of the RCS stripper foil can be established.
Yamazaki, Yoshio; Yoshimoto, Masahiro; Saha, P. K.; Takeda, Osamu; Kinsho, Michikazu; Taguchi, Tomitsugu; Yamamoto, Shunya; Kurihara, Toshikazu*; Sugai, Isao*
no journal, ,
no abstracts in English
Yoshimoto, Masahiro; Saha, P. K.; Kinsho, Michikazu; Taguchi, Tomitsugu*; Yamamoto, Shunya*; Sugai, Isao*; Yamazaki, Yoshio
no journal, ,
For a charge stripper foil in the RCS, we applied a Hybrid type Boron-doped Carbon foil which is produced with the arc-discharge method. Actually it has enough toughness to stand high-intensity beam operation less than 500kW. Recently a graphite foil developed by TASC in Japan was also tried to adopt as the stripping foil for the beam operation in J-PARC, and it had good performance in the condition of 200kW beam operation. It is very important toward 1MW beam operation to predict the lifetime of foils. Now we cannot estimate the lifetime of these foils for the 400MeV beam operation from the results of offline foils study. In order to evaluate the lifetime of foils quantitatively, we started to obtain Raman spectra of foils irradiated each ion such as H, He and Ar in energy of different energy such as 350keV, 2 and 3 MeV. We will try to predict the lifetime of foils by estimating peaks' shifts of Raman spectra as an indicator corresponding to DPA(Displacement Per Atom) by PHITS code.
Nakanishi, Toshimichi; Komatsu, Tetsuya; Hongo, Misao*; Noguchi, Marie*; Miyamoto, Tatsuki*; Kimori, Taiga*; Sugai, Toshihiko*
no journal, ,
no abstracts in English
