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Mio, Keigo; Ogiwara, Norio; Marushita, Motoharu*; Arai, Hideyuki*; Goto, Keiichi*
JAEA-Technology 2009-064, 40 Pages, 2010/03
JAEA-Technology-2009-064.pdf:9.57MB
Intense of radiation fields will be expected since large intensity proton beam current of J-PARC 3GeV RCS (Rapid-Cycling Synchrotron). 
-ray irradiation tests of vacuum system equipment were carried out to evaluate radiation resistance for RCS. Requirement of radiation resistance of vacuum equipment is assumed as 10 MGy. -ray irradiation examination has been done to select the vacuum equipment. As a result, cooling-fan, feed-through-connector, baking heater, piping sealants have been shown to have radiation resistance as 10 MGy. Dry scroll vacuum pump was shown as only 1 MGy from the restriction of the material of the chip seal (Teflon).
Ogiwara, Norio; Kinsho, Michikazu; Kamiya, Junichiro; Yamamoto, Kazami; Yoshimoto, Masahiro; Hikichi, Yusuke; Kanazawa, Kenichiro; Mio, Keigo; Takiyama, Yoichi; Suganuma, Kazuaki; et al.
Vacuum, 84(5), p.723 - 728, 2009/12
Times Cited Count：7 Percentile：30.19(Materials Science, Multidisciplinary)To minimize the radiation exposure during maintenance, it is necessary to compose the 3-GeV RCS vacuum system with reliable components which have long life time in such a high level of radiation. In addition, it is necessary to keep the operating pressure with beam in ultra high vacuum for suppressing the pressure instability. Thus we should think of not only the outgassing mainly due to ion desorption but also the pumping efficiency. From the above, the vacuum system was designed. The ring is divided by the isolation valves into 6 sections, which can be pumped down independently. For avoiding any eddy current loss ceramic ducts are used in the bending and focusing magnets. These ducts are connected to the Ti ducts, putting the Ti bellows between. Here, we adopt pure Ti as a material for the ducts and bellows because of its small residual radioactivity. The ring is evacuated with 20 ion pumps (0.7 m
/s) and 24 turbomolecular pumps (TMPs) (1.3 m/s), which are attached to the Ti ducts. The TMPs are used for not only rough pumping but also evacuation during the beam operation. Especially a collimator system for localizing beam losses in a restricted area is evacuated with the TMPs, because the outgassing from this region will be probably the largest. On the other hand, each arc section is pumped by 4 ion pumps and 2 TMPs. To realize the above system, we have developed some components such as large aperture ceramic ducts and TMPs with high radioactive-resistance, as well as several kinds of heat treatment to reduce the outgassing. Finally, we have realized the UHV without baking in the RCS and the beam operation has been succeeded until now.
Mio, Keigo; Ogiwara, Norio; Furukori, Hisayoshi*; Arai, Hideyuki*; Nishizawa, Daiji*; Nishidono, Toshiro*; Hikichi, Yusuke
JAEA-Technology 2009-018, 86 Pages, 2009/04
JAEA-Technology-2009-018.pdf:13.44MB
Material characterization and development has been carried out for cable insulation suitable for use in the J-PARC 3-GeV RCS radiation environment. In spite of its high cost, PEEK (polyether-ether-ketone) has emerged as the leading candidate satisfying requirements of being non-halogen based, highly incombustible and with radiation resistant at least 10 MGy, along with the usual mechanical characteristics such as good elongation at break, which are needed in a cable insulation. -ray irradiation tests have been done in order to study radiation resistance of PEEK cable. Further, mechanical, electrical and fire retardant characteristics of a complete cable such as would be used at the J-PARC RCS were investigated. As a result, PEEK cables were shown to be not degraded by radiation up to at least 10 MGy, and thus could be expected to operate stably under the 3-GeV RCS radiation environment.
Mio, Keigo; Ogiwara, Norio; Hikichi, Yusuke; Marushita, Motoharu*; Arai, Hideyuki*; Goto, Keiichi*; Nishizawa, Daiji*; Furukori, Hisayoshi*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.252 - 254, 2008/00
-Ray irradiation tests of vacuum system equipment were carried out to evaluate radiation resistance for J-PARC 3GeV RCS(Rapid-Cycling Synchrotron). Intense of radiation fields will be expected since large intensity proton beam current of RCS. Regarding Steady operation and radiation protection, radiation hardness is required approximately 10MGy to 100MGy. Cable, Feed-through-connector, Cooling-fan, Baking heater, piping Sealants have been tested. All the examination objects were evaluated to have radiation hardness at least 10MGy and expected to operate with stability under radiation field of 3GeV RCS.
