Construction of J-PARC LINAC-RCS beam transport line new vacuum system

Kobayashi, Fuminori; Kamiya, Junichiro; Takahashi, Hiroki; Suzuki, Yasuo*; Tasaki, Ryuta*

JAEA-Technology 2024-007, 28 Pages, 2024/07

JAEA-Technology-2024-007.pdf:2.52MB

In J-PARC LINAC, the vacuum system is in place to maintain an ultra-high vacuum in the beam transport line (LINAC to 3GeV RCS beam transportation line: L3BT) between the LINAC to the 3GeV synchrotron. The vacuum system is installed in the LINAC and L3BT buildings and consists of vacuum pumps, vacuum gauges, beam line gate valves (BLGVs), and other vacuum. In existing vacuum systems, vacuum equipment is controlled independently for each area, and vacuum equipment can be operated regardless of the status of adjacent areas. This makes it impossible to eliminate erroneous operation due to human error. In addition, when a vacuum deterioration occurs in the beam transport line, the vacuum deterioration ILK signal is transmitted to the BLGV relay unit via the MPS transmission signal, which causes the BLGVs to be forcibly closed. Because the ILK signal transmission range extends to all BLGVs in the L3BT, however, BLGVs in areas unaffected by vacuum deterioration are also forced to close. This could cause problems such as unnecessary open/close operations leading to more frequent maintenance cycles of the BLGVs. In addition, since the BLGV is operated using the MPS signal path, maintenance of the vacuum control system requires work involving the MPS signal path, making it difficult to maintain the vacuum control system alone and making the work complicated. To solve these problems, it is necessary to improve maintainability by separating the signal paths and automatically controlling BLGV separately. Therefore, the vacuum control system was modified and constructed with the aim of realizing a control system that takes into account the safety and efficient maintenance and operation of the L3BT vacuum system. This report summarizes the development and use of the L3BT vacuum system control system.

Third international challenge to model the medium- to long-range transport of radioxenon to four Comprehensive Nuclear-Test-Ban Treaty monitoring stations

Maurer, C.*; Galmarini, S.*; Solazzo, E.*; Kumierczyk-Michulec, J.*; Bar, J.*; Kalinowski, M.*; Schoeppner, M.*; Bourgouin, P.*; Crawford, A.*; Stein, A.*; et al.

Journal of Environmental Radioactivity, 255, p.106968_1 - 106968_27, 2022/12

https://doi.org/10.1016/j.jenvrad.2022.106968

After performing multi-model exercises in 2015 and 2016, a comprehensive Xe-133 atmospheric transport modeling challenge was organized in 2019. For evaluation measured samples for the same time frame were gathered from four International Monitoring System stations located in Europe and North America with overall considerable influence of IRE and/or CNL emissions. As a lesion learnt from the 2nd ATM-Challenge participants were prompted to work with controlled and harmonized model set ups to make runs more comparable, but also to increase diversity. Effects of transport errors, not properly characterized remaining emitters and long IMS sampling times (12 to 24 hours) undoubtedly interfere with the effect of high-quality IRE and CNL stack data. An ensemble based on a few arbitrary submissions is good enough to forecast the Xe-133 background at the stations investigated. The effective ensemble size is below five.

LEBT commissioning of the J-PARC LINAC

Shibata, Takanori*; Ikegami, Kiyoshi*; Liu, Y.*; Maruta, Tomofumi*; Naito, Fujio*; Takagi, Akira*; Asano, Hiroyuki; Kondo, Yasuhiro; Miura, Akihiko; Oguri, Hidetomo; et al.

Proceedings of 28th International Linear Accelerator Conference (LINAC 2016) (Internet), p.251 - 253, 2017/05

https://doi.org/10.18429/JACoW-LINAC2016-MOPLR052

After upgrade of J-PARC Linac in 2014, Low Energy Beam Transport (LEBT) beam commissioning of the J-PARC LINAC has been made for improving H beam intensity extracted from Linac. Currents of two solenoid coils and steering magnets in LEBT are optimized with extraction and acceleration voltages for static acceleration in ion source (IS) which decides on an initial emittance diagram of H beam. As a result of LEBT and IS parameter optimization, beam transmission rate of RFQ has been reached up to 96% in 50 mA H current operation. Moreover, PIC-MC (Particle-In-Cell Monte-Carlo) simulation models developed for H transport in LEBT. Comparison between experimental and numerical results are presented to clarify beam physics from IS exit to RFQ entrance.

Update status of the J-PARC 3NBT control system

Oi, Motoki; Meigo, Shinichiro; Akutsu, Atsushi*; Kawasaki, Tomoyuki; Nishikawa, Masaaki*; Fukuda, Shimpei

Proceedings of 12th International Topical Meeting on Nuclear Applications of Accelerators (AccApp '15), p.89 - 96, 2016/00

At J-PARC, 3 GeV proton beam with power of 1MW is delivered to the spallation neutron source (JSNS) through beam transport line called 3NBT. At the high power accelerator facilities even a small abnormal event has a possibility to be critical so that the beam control system is crucial. In order to find tiny anomaly, rapid data analysis system is required. We developed control and data analysis system based on the Experimental Physics and Industrial Control System (EPICS) and Control System Studio (CSS). To carry out beam tuning efficiently, the beam control system based on the Strategic Accelerator Design (SAD) code has been developed. With the several shots of beam and by the one click of operational panel of the screen, required magnet field can be calculated and set automatically. Also we developed automated e-mail system to announce the abnormal event to the experts persons. With these systems, we can reduce both beam tuning time and down time.

Mechanical properties of small size specimens of F82H steel

Wakai, Eiichi; Otsuka, Hideo*; Matsukawa, Shingo; Furuya, Kazuyuki*; Tanigawa, Hiroyasu; Oka, Keiichiro*; Onuki, Somei*; Yamamoto, Toshio*; Takada, Fumiki; Jitsukawa, Shiro

Fusion Engineering and Design, 81(8-14), p.1077 - 1084, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.08.072

no abstracts in English

Radiation hardening and -embrittlement due to He production in F82H steel irradiated at 250 C in JMTR

Wakai, Eiichi; Jitsukawa, Shiro; Tomita, Hideki*; Furuya, Kazuyuki; Sato, Michitaka*; Oka, Keiichiro*; Tanaka, Teruyuki*; Takada, Fumiki; Yamamoto, Toshio*; Kato, Yoshiaki; et al.

Journal of Nuclear Materials, 343(1-3), p.285 - 296, 2005/08

https://doi.org/10.1016/j.jnucmat.2004.10.167

The dependence of helium production on radiation-hardening and -embrittlement has been examined in a reduced-activation martensitic F82H steel doped with B, B and B+B irradiated at 250C to 2.2 dpa. The total amounts of doping boron were about 60 massppm. The range of He concentration produced in the specimens was from about 5 to about 300 appm. Tensile and fracture toughness tests were performed after neutron irradiation. 50 MeV-He irradiation was also performed to implant about 85 appm He atoms at 120C by AVF cyclotron to 0.03 dpa, and small punch testing was performed to obtain DBTT. Radiation-hardening of the neutron-irradiated specimens increased slightly with increasing He production. The 100 MPam DBTT for the F82H+B, F82H+B+B, and F82H+B were 40, 110, and 155C, respectively. The shifts of DBTT due to He production were evaluated as about 70C by 150 appmHe and 115C by 300 appmHe. The DBTT shift in the small punch testing was evaluated as 50C.

Formation of organically bound deuterium at each growing stage of rice

Atarashi-Andoh, Mariko; Kumakura, Yasuharu*; Amano, Hikaru; Fukui, Masami*

Fusion Science and Technology, 48(1), p.771 - 774, 2005/07

https://doi.org/10.13182/FST05-A1034

Uptake of tritium by food plants is an important pathway in transferring tritium to the human body. Plants take up tritium as the form of water and a part of tritiated water (HTO) is converted to organically bound tritium (OBT). The formation of OBT in plants depends on the growth stage when the contamination occurs. Potted rice plants were exposed to deuterated water vapor, as a substitute for HTO vapor, for 4 h at 5 different times during the grain ripening period to estimate the influence of the growth stage on the formation and retention of organically bound deuterium (OBD) in rice. The plants were grown outside before and after the exposure experiments and were exposed to deuterated water vapor in a laboratory in a small chamber equipped with controllers of temperature, humidity and light intensity.The mass of OBD in grain at harvest showed the highest value when the exposure was carried out in the early stage of the ripening period. When the exposure was carried out after 26 day from the heading, the increase of OBD in the grain was a little.

Effect of heat treatments on mechanical properties and microstructures of 8Cr-2W(F82H) steel doped with boron or boron and nitrogen

Wakai, Eiichi; Sato, Michitaka*; Okubo, Nariaki; Sawai, Tomotsugu; Shiba, Kiyoyuki; Jitsukawa, Shiro

Nihon Kinzoku Gakkai-Shi, 69(6), p.460 - 464, 2005/06

https://doi.org/10.2320/jinstmet.69.460

no abstracts in English

Status of research activities for development of CTBT-related technologies in JAERI

Shinohara, Nobuo; Inoue, Yoji; Uchikoshi, Takako*; Oda, Tetsuzo*; Kumata, Masahiro; Kurosawa, Yoshiaki; Hirota, Naoki*; Hokida, Takanori; Nakahara, Yoshinori*; Yamamoto, Yoichi

Dai-25-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.51 - 58, 2005/00

The Japan Atomic Energy Research Institute (JAERI) conducts researches and developments related to Comprehensive Nuclear-Test-Ban Treaty (CTBT) on the basis of Japan's pragmatic and progressive efforts toward peaceful use of atomic energy and non-proliferation with the goal of realizing a peaceful and safe world free from nuclear weapons. The Treaty aims for the establishment of a global verification regime comprising an International Monitoring System (IMS) and the JAERI has engaged in the following activities: construction and operation of the radionuclide monitoring stations at Okinawa (RN37) and Takasaki (RN38) and the certified radionuclide laboratory at Tokai (RL11) as specified in Annex 1 of CTBT Protocol, and preparation of the National Data Center at Tokai (JAERI NDC). Research activities of JAERI related to the CTBT verification regime are presented in the paper. The subjects of this presentation are (1) an overview of the CTBT verification regime, (2) construction and operation of RN37, RN38 and RL11, and (3) preparation of the JAERI NDC for radionuclide data.

Investigation of photo neutralization efficiency of high intensity H beam with Nd:YAG laser in J-PARC

Tomisawa, Tetsuo; Akikawa, Hisashi; Sato, Susumu; Ueno, Akira; Kondo, Yasuhiro; Oigawa, Hiroyuki; Sasa, Toshinobu; Hasegawa, Kazuo; Lee, S.*; Igarashi, Zenei*; et al.

Proceedings of 7th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators (DIPAC 2005), p.275 - 277, 2005/00

http://accelconf.web.cern.ch/Accelconf/d05/PAPERS/POW018.PDF

The photo neutralization method with Nd:YAG laser for negative hydrogen ions has been expected as an available candidate for the transverse beam profile measurement. The fraction of photo detached electron can also be used for charge exchange procedure to extract very low power proton beam for Transmutation Experimental Facility in J-PARC. The laser system has advantages of maintenance and radiation hardness in high intensity proton accelerators. In order to establish the low power beam extraction system and beam profile monitor, the photo neutralization efficiency must be surveyed in practical beam line with high intensity H beam. In this paper, an experimental set-up and preliminary results of photo neutralization method for intense H beam in J-PARC MEBT1 are described.