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Yamada, Ippei; Kamiya, Junichiro
Review of Scientific Instruments, 95(12), p.123308_1 - 123308_11, 2024/12
Times Cited Count:1 Percentile:39.80(Instruments & Instrumentation)A gas-sheet beam profile monitor enabling non-destructive two-dimensional profile measurements of a high-intensity beam by capturing an image of a beam-induced fluorescence was developed. For quantitative profile measurements, the monitor's response function comprising, e.g., the gas sheet density distribution and the detector's sensitivity distributions must be experimentally clarified because the monitor output is a converted profile with the response function. A response function measurement method was devised based on the beam-profile-measurement method formula of the monitor. The response function was obtained by injecting a thin electron beam into the developed monitor and scanning its center position in transverse. The measured response function was evaluated by the J-PARC 3 MeV, 60 mA H beam profile measurement. The 2-D beam profile was successfully reconstructed with the measured response function within the 2.74% residual of the least-squares method and 6.01% experimental statistic deviation. The projected 1-D profiles agreed well with those measured using a wire-scanning-type profile monitor.
Kamiya, Junichiro; Abe, Kazuhide; Fujimori, Shinichi; Fukuda, Tatsuo; Kobata, Masaaki; Morohashi, Yuko; Tsuda, Yasutaka; Yamada, Ippei; Yoshigoe, Akitaka
e-Journal of Surface Science and Nanotechnology (Internet), 22(4), p.316 - 326, 2024/08
The activation and deterioration mechanisms of the Ti-Zr-V non-evaporable getter (NEG) coating have been investigated. Operando analysis of the surface chemical composition change of the Ti-Zr-V coating was performed by the synchrotron radiation photoelectron spectroscopy (SRPES) during the process of raising the sample temperature to 250C, corresponding to the activation process of NEG coating. The surface oxidation process was also characterized by the SRPES during the injection of O_2 gas into the chamber while keeping the sample temperature at 250
C, corresponding to the deterioration process of NEG coating, i.e. surface oxidation and oxygen diffusion to the coating interior. The depth profile of the oxidized sample was measured with X-ray photoelectron spectroscopy. The results shows, in the activation process, the surface Zr gets the oxygen from the oxides of Ti and V at the first stage, resulting in the metallic Ti and V on the surface, and the oxygen of the Zr-oxide and/or Zr sub-oxides diffuse to the interior of the coating in the continuous temperature rise, resulting in the metallic Zr on the surface. It is further suggested that the deterioration of the Ti-Zr-V NEG coating means the Zr and secondary Ti are oxidized deep into the coating, resulting in the restriction of the oxygen migration from the NEG compositions on the surface and consequently the lack of surface metallization.
Kamiya, Junichiro; Oi, Motoki; Kobayashi, Fuminori; Sakai, Kenji; Yamada, Ippei
Vacuum and Surface Science, 67(4), p.186 - 191, 2024/04
This report describes the usage, specification, troubles and countermeasures of dry pumps in the Japan Proton Accelerator Research Complex (J-PARC). In J-PARC, while dry scroll pumps (DSP) are widely used, many are being replaced with roots pumps due to frequent maintenance and troubles of DSP. Some of the facilities use roots pumps with special specifications, such as radiation-resistant specifications, separate power supply, and with diaphragm type, etc. Although some problems have occurred with both DSPs and roots pumps, they have been addressed by revising maintenance methods and improving parts, contributing to stable operation for users.
Yamada, Kazuo*; Hokora, Hideyuki*; Maruyama, Ippei*; Aihara, Haruka; Tomita, Sayuri*; Tojo, Yasumasa*; Shibuya, Kazutoshi*; Hosokawa, Yoshifumi*; Igarashi, Go*; Koma, Yoshikazu
Proceedings of Waste Management Symposia 2024 (WM2024) (Internet), 7 Pages, 2024/03
Yamamoto, Kazami; Moriya, Katsuhiro; Okita, Hidefumi; Yamada, Ippei; Chimura, Motoki; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Masanobu; Morishita, Takatoshi; et al.
Journal of Neutron Research, 26(2-3), p.59 - 67, 2024/01
The linac and 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex was designed to provide 1-MW proton beams to the following facilities. Thanks to the improvement works of the accelerator system, we successfully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce requirement of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also been continuing study to achieve up to 2 MW beam in J-PARC RCS.
Yamada, Ippei; Chimura, Motoki; Kamiya, Junichiro; Kinsho, Michikazu
Journal of Physics; Conference Series, 2687(7), p.072018_1 - 072018_6, 2024/01
Times Cited Count:0 Percentile:0.00(Physics, Atomic, Molecular & Chemical)no abstracts in English
Nagayama, Shota; Harada, Hiroyuki; Shimogawa, Tetsushi*; Sato, Atsushi*; Yamada, Ippei; Chimura, Motoki; Kojima, Kunihiro; Yamamoto, Kazami; Kinsho, Michikazu
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.526 - 530, 2023/11
We have been developing "Non-destructive electrostatic septum" for a slow extraction. This septum has multiple electrodes placed around the region without the beam hitting and separate the beam by its electric field. To evaluate its electric field, we have built a prototype septum and a test machine, which consists of an electron gun and monitors. This test machine can measure the electric field indirectly by using a narrow electron beam. The experiment results of prototype septum is good agreement with the calculation one. However, this electric field distribution is not enough to separate the beam. A step function-like electric field distribution is ideal for the beam separation with minimal negative effect on the beam. We have studied to improve the electrode configuration to match the beam shape. In this paper, we present the result of the electric field measurements and the septum improvement. Additionally, we describe the future plan of this development.
Yamamoto, Kazami; Moriya, Katsuhiro; Okita, Hidefumi; Yamada, Ippei; Chimura, Motoki; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Masanobu; Morishita, Takatoshi; et al.
Proceedings of 68th ICFA Advanced Beam Dynamics Workshop on High Intensity and High Brightness Hadron Beams (HB2023) (Internet), p.270 - 273, 2023/10
The 3-GeV rapid-cycling synchrotron at the Japan Pro-ton Accelerator Research Complex was designed to provide 1-MW proton beams to the following facilities. Thanks to the improvement works of the accelerator system, we successfully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce requirement of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also continued study to achieve more than 2 MW beam in J-PARC RCS.
Yamamoto, Kazami; Yamada, Ippei
Proceedings of 14th International Particle Accelerator Conference (IPAC 23) (Internet), p.2339 - 2341, 2023/05
The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) provides more than 800 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). We have been continuing a beam study to achieve 1-MW, design power operation. In addition, we have also improved and maintained the accelerator components to establish a stable operation. This paper reports the status of the J-PARC RCS in recent years. In summary, the RCS can be operated quite stable, but we were not able to keep 1-MW beam in the summer condition.
Yamada, Kazuo*; Tojo, Yasumasa*; Aihara, Haruka; Tomita, Sayuri*; Hokora, Hideyuki*; Shibuya, Kazutoshi*; Koma, Yoshikazu; Igarashi, Go*; Hosokawa, Yoshifumi*; Maruyama, Ippei*
Proceedings of Waste Management Symposia 2023 (WM2023) (Internet), 12 Pages, 2023/02
Nagayama, Shota; Harada, Hiroyuki; Shimogawa, Tetsushi*; Yamada, Ippei; Chimura, Motoki; Yamamoto, Kazami; Kinsho, Michikazu
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.503 - 507, 2023/01
Synchrotron accelerators realize physics experiments and radiation cancer treatment using the slow extraction technique, in which beams are stored in the ring and gradually delivered. We have devised and are currently developing a "non-destructive electrostatic septum" based on a new method, which in principle cannot be solved by conventional methods and is a cause of equipment failure and output limitation. It is ideal to generate a force distribution similar to a staircase function with discontinuous gaps at the boundary. In this presentation, we will show the calculation method for optimizing the electrode and wire configuration to generate a Lorentz force with a distribution similar to a staircase function in vacuum, and the calculation results of the beam breakup due to the generated Lorentz force. The compact proof-of-principle machine developed for the ongoing demonstration of this method will also be introduced.
Yamada, Ippei; Wada, Motoi*; Kamiya, Junichiro; Kinsho, Michikazu
Journal of Physics; Conference Series, 2244, p.012077_1 - 012077_6, 2022/04
Times Cited Count:1 Percentile:55.69(Engineering, Electrical & Electronic)no abstracts in English
Igarashi, Go*; Haga, Kazuko*; Yamada, Kazuo*; Aihara, Haruka; Shibata, Atsuhiro; Koma, Yoshikazu; Maruyama, Ippei*
Journal of Advanced Concrete Technology, 19(9), p.950 - 976, 2021/09
Times Cited Count:5 Percentile:24.97(Construction & Building Technology)Yamada, Ippei; Wada, Motoi*; Moriya, Katsuhiro; Kamiya, Junichiro; Saha, P. K.; Kinsho, Michikazu
Physical Review Accelerators and Beams (Internet), 24(4), p.042801_1 - 042801_13, 2021/04
Times Cited Count:9 Percentile:71.33(Physics, Nuclear)A transverse beam profile monitor that visualizes a two-dimensional beam-induced fluorescent image was developed. The monitor employs a sheet-shaped gas flow formed by a technique of rarefied gas dynamics. A simplified analysis method was developed to reconstruct the beam intensity profile from the obtained image. The developed profile monitor and the analysis method were applied to measure the J-PARC 3 MeV H beam profile. The root mean square values of the profiles were consistent with the ones obtained by a wire-scanning-type beam profile monitor. The beam loss due to the gas sheet injection was measured as a beam-current reduction. The amount of the beam current decreased in proportion to the gas sheet flux and the reduction ranged from 0.004 to 2.5%. The assembled system was capable of reconstructing a beam profile from a single shot beam pulse (1.7
10
protons in 50
s).
Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.
Proceedings of International Waste Management Symposia 2021 (WM2021) (CD-ROM), 10 Pages, 2021/03
Yamada, Tomonori; Takebe, Toshihiko*; Ishizuka, Ippei*; Daido, Hiroyuki*; Hanari, Toshihide; Shibata, Takuya; Omori, Shinya*; Kurosawa, Koichi*; Sasaki, Go*; Nakada, Masahiro*; et al.
Journal of Nuclear Science and Technology, 56(12), p.1171 - 1179, 2019/12
Times Cited Count:1 Percentile:8.72(Nuclear Science & Technology)We describe a new chipping technique combined with a water-jet technique as one of the candidate techniques for the retrieval of fuel debris and support structures as part of the decommissioning of the Fukushima Daiichi Nuclear Power Station. We performed proof-of-principle experiments to demonstrate the removal capability of metal parts, where we focused on the observation of removal processes from a metallic sample using a 5.5-kW continuous wave fiber laser combined with continuous and pulsed water jets.
Kamiya, Junichiro; Okabe, Kota; Kinsho, Michikazu; Moriya, Katsuhiro; Yamada, Ippei; Ogiwara, Norio*; Hikichi, Yusuke*; Wada, K.*
Journal of Physics; Conference Series, 1350, p.012149_1 - 012149_6, 2019/12
Times Cited Count:3 Percentile:79.08(Physics, Particles & Fields)To obtain a getter effect to titanium vacuum duct surface, the method to remove the oxide on the surface by sputtering with ionized molecules has been developed. In the method, a sheet-shaped gas distribution with a uniform and high density is generated through a narrow slit by a small amount of gas. In this report, the gas density distribution was calculated by the Monte Carlo simulation code. As a result, it was found that a gas injection from both directions was effective to generate uniform density distribution. Furthermore, the gas injection method was applied to a non-destructive beam profile monitor, that detects ions generated by the interaction between gas molecules and beam. In this monitor, dependence of the beam profile on the injected gas amount was measured. A small amount of injected gas was found to be ideal for the beam profile measurements in the unsaturated and a high S/N ratio region.
Yamada, Ippei; Ogiwara, Norio*; Hikichi, Yusuke*; Kamiya, Junichiro; Kinsho, Michikazu
Vacuum and Surface Science, 62(7), p.400 - 405, 2019/07
no abstracts in English
Yamada, Ippei; Ogiwara, Norio*; Hikichi, Yusuke*; Kamiya, Junichiro; Kinsho, Michikazu
Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.2567 - 2570, 2019/06
no abstracts in English
Yamada, Kazuo*; Maruyama, Ippei*; Koma, Yoshikazu; Haga, Kazuko*; Igarashi, Go*; Shibuya, Kazutoshi*; Aihara, Haruka
Proceedings of International Waste Management Symposia 2019 (WM2019) (CD-ROM), 6 Pages, 2019/03