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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：0 Percentile：0.33no 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：59.66(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：2 Percentile：48.86(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：13.66(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：2 Percentile：75.87To 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
Yamada, Ippei; Ogiwara, Norio*; Hikichi, Yusuke*; Kamiya, Junichiro; Kinsho, Michikazu
Proceedings of 15th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.88 - 92, 2018/08
no abstracts in English
Hanari, Toshihide; Takebe, Toshihiko*; Yamada, Tomonori; Daido, Hiroyuki; Ishizuka, Ippei*; Omori, Shinya*; Kurosawa, Koichi*; Sasaki, Go*; Nakada, Masahiro*; Sakai, Hideaki*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 3 Pages, 2017/04
In decommissioning of Fukushima Daiichi Nuclear Power Station, a retrieval process of fuel debris in the Primary Containment Vessel by a remote operation is one of the key issues. In this process, prevention of spreading radioactive materials is one of the important considerations. Furthermore, an applicable technique to the process requires keeping of reasonable processing-efficiency. We propose to use the combined technique including a laser light and a water jet as a retrieval technique of the fuel debris. The laser processing technique combined with a repetitive pulsed water jet could perform an efficient retrieval processing. Our experimental result encourages us to promote further development of the technique towards a real application at Fukushima Daiichi Nuclear Power Station.
-FeSi
Yamada, Yoichi; Wakaya, Ippei*; Ouchi, Shinji*; Yamamoto, Hiroyuki; Asaoka, Hidehito; Shamoto, Shinichi; Udono, Haruhiko*
Surface Science, 602(18), p.3006 - 3009, 2008/09
Times Cited Count：6 Percentile：30.88(Chemistry, Physical)Well-defined clean surfaces of single crystalline -FeSi have for the first time been prepared and characterized at the atomic scale. Surface oxide was removed by heating the crystal at 850 
C in ultra-high vacuum (UHV), resulted in an atomically-flat, clean surface. Scanning tunneling microscope (STM) and low-energy electron diffraction (LEED) measurements reveal the absence of long-range surface reconstruction in the low-index (100), (101) and (110) surfaces, which is unique among compound semiconductors. However a significant number of surface defects could still be found within the clean surface. Characterizing and controlling of those surface defects will be necessary in order to use this material in applications.
-FeSi single crystalsWakaya, Ippei*; Muroga, Masataka*; Ouchi, Shinji*; Udono, Haruhiko*; Yamada, Yoichi; Yamamoto, Hiroyuki; Kikuma, Isao*
no journal, ,
RHEED observation of surface has been performed on -FeSi single crystals.
-FeSi single crystalYamada, Yoichi; Wakaya, Ippei*; Ouchi, Shinji*; Yamamoto, Hiroyuki; Udono, Haruhiko*
no journal, ,
Preparation method of well defined -FeSi(110) single crystal surface has been investigated.
-FeSi thin films on various oriented substrates by MBEOuchi, Shinji*; Wakaya, Ippei*; Udono, Haruhiko*; Yamada, Yoichi; Yamamoto, Hiroyuki; Esaka, Fumitaka
no journal, ,
Homoepitaxial formation of -FeSi thin films on various oriented substrates has been discussed.
-FeSiMao, W.; Wakaya, Ippei*; Yamada, Yoichi; Esaka, Fumitaka; Yamamoto, Hiroyuki; Shamoto, Shinichi; Yamaguchi, Kenji; Udono, Haruhiko*
no journal, ,
Thin films of semiconducting -FeSi keep attracting considerable attentions for their promising applicability to the Si-based optoelectronics devices. Recently, large single-crystalline -FeSi has successfully been synthesized, providing a substrate for a well-defined homoepitaxy film. As a first step toward good homoepitaxy of -FeSi, we prepare and characterize low-index surfaces of -FeSi single crystal. Both LEED and STM reveal the absence of the long-ranged surface reconstruction for each face, which is favorable for the homoepitaxy on this substrate. On the other hand, STM suggests a presence of a significant amount of surface defects for each face, which should be improved in the next step. In addition to structural analysis, the stoichiometry of clean surfaces will be discussed on the basis of XPS and SIMS measurements.
-FeSi homoepitaxial growthWakaya, Ippei*; Ochiai, Kunihito*; Udono, Haruhiko*; Nagano, Takatoshi*; Yamada, Yoichi; Yamamoto, Hiroyuki; Esaka, Fumitaka
no journal, ,
Deposit condition in the first stage of -FeSi homoepitaxial growth has been investigated.
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Yamada, Yoichi*; Wakaya, Ippei*; Ouchi, Shinji*; Udono, Haruhiko*; Tsuru, Tomohito; Esaka, Fumitaka; Yamamoto, Hiroyuki
no journal, ,
no abstracts in English
Takebe, Toshihiko*; Hanari, Toshihide; Yamada, Tomonori; Daido, Hiroyuki; Ishizuka, Ippei*; Omori, Shinya*; Kurosawa, Koichi*; Sasaki, Go*; Nakada, Masahiro*; Sakai, Hideaki*
no journal, ,
no abstracts in English
