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Kaburagi, Masaaki; Miyamoto, Yuta; Mori, Norimasa; Iwai, Hiroki; Tezuka, Masashi; Kurosawa, Shunsuke*; Tagawa, Akihiro; Takasaki, Koji
Journal of Nuclear Science and Technology, 62(3), p.308 - 316, 2025/03
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Morishita, Yuki; Sagawa, Naoki; Fujisawa, Makoto; Kurosawa, Shunsuke*; Sasano, Makoto*; Hayashi, Masateru*; Tanaka, Hiroki*
Radiation Measurements, 181, p.107371_1 - 107371_5, 2025/02
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The effects of different types of radiation on a high-resolution alpha imager developed using an electron multiplying charge-coupled device (EMCCD) camera were investigated. This imager was originally developed to visualize alpha particles from Pu oxide particles at decommissioning sites. Other types of radiation such as beta particles, gamma rays, and neutrons are also present. The purpose of this study is to investigate the effects of these background radiations on the imager and to develop a method to discriminate between alpha particles and other types of radiation. When measuring gamma rays, and neutrons, the sensor of the EMCCD camera generated high intensity signals due to gamma rays and neutrons. These radiations were identified by image processing. The image values were binarized and the findContours function was applied to count the number of alpha particle spots. The results showed that alpha and gamma (neutron) radiation can be discriminated by using differences in intensity. This method will be useful for visualizing alpha particles at decommissioning sites.
Morishita, Yuki; Kurosawa, Shunsuke*; Yamaji, Akihiro*; Hayashi, Masateru*; Sasano, Makoto*; Makita, Taisuke*; Azuma, Tetsushi*
Scientific Reports (Internet), 11, p.5948_1 - 5948_11, 2021/03
Times Cited Count：5 Percentile：39.12(Multidisciplinary Sciences)The internal exposure of workers who inhale plutonium dioxide particles in nuclear facilities is a crucial matter for human protection from radiation. To determine the activity median aerodynamic diameter values at the working sites of nuclear facilities in real time, we developed a high-resolution alpha imager using a ZnS(Ag) scintillator sheet, an optical microscope, and an electron-multiplying charge-coupled device camera. Then, we designed and applied a setup to measure a plutonium dioxide particle and identify the locations of the individual alpha particles in real time. Employing a Gaussian fitting, we evaluated the average spatial resolution of the multiple alpha particles was evaluated to be 16.2 umFWHM with a zoom range of 5 x. Also, the spatial resolution for the plutonium dioxide particle was 302.7 umFWHM due to the distance between the plutonium dioxide particle and the ZnS(Ag) scintillator. The influence of beta particles was negligible, and alpha particles were discernible in the alpha-beta particle contamination. The equivalent volume diameter of the plutonium dioxide particle was calculated from the measured count rate. These results indicate that the developed alpha imager is effective in the plutonium dioxide particle measurements at the working sites of nuclear facilities for internal exposure dose evaluation.
measurement and analysis techniques in X-ray photoelectron spectroscopy; From NAP-HARPES to 4D-XPSToyoda, Satoshi*; Yamamoto, Tomoki*; Yoshimura, Masashi*; Sumida, Hirosuke*; Mineoi, Susumu*; Machida, Masatake*; Yoshigoe, Akitaka; Suzuki, Satoru*; Yokoyama, Kazushi*; Ohashi, Yuji*; et al.
Vacuum and Surface Science, 64(2), p.86 - 91, 2021/02
We have developed measurement and analysis techniques in X-ray photoelectron spectroscopy. To begin with, time-division depth profiles of gate stacked film interfaces have been achieved by NAP-HARPES (Near Ambient Pressure Hard X-ray Angle-Resolved Photo Emission Spectroscopy) data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division ARPES data, which enables us to realize 4D-XPS analysis. It is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling in NAP-HARPES data is effective to perform dynamic measurement of depth profiles with high precision.
Arikawa, Yasunobu*; Ikeda, Yujiro; Shimizu, Hirohiko*; Hanayama, Ryohei*; Kondo, Yasuharu*; Kurosawa, Shunsuke*
Reza Kenkyu, 46(11), p.634 - 640, 2018/11
Compact neutron sources have been used as various diagnostics such as a neutron diffraction, neutron resonant analysis, and neutron radiography. The developments of the neutron detectors are essential for all of these applications, while the techniques are strongly dependent on the neutron energy and the aim of the measurement. This paper reviews neutron detection techniques pertinent to promote compact neutron source uses. Along with general neutron detection systems with conventional counters for slow neutrons, we have highlighted detectors for high energy neutrons with high time resolution and high sensitivity which could be applied in a laser-driven compact neutron source.
(Al,Ga)
O
scintillator Compton camera mounted on an unmanned helicopterShikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.
Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12
Times Cited Count：45 Percentile：95.89(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4
4 to 88 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m 60 m and 65 m 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the 
-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10
).
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
JAEA-Technology-2009-030.pdf:69.18MB
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Morishita, Yuki; Sagawa, Naoki; Fujisawa, Makoto; Kurosawa, Shunsuke*; Sasano, Makoto*; Hayashi, Masateru*; Tanaka, Hiroki*
no journal, ,
This study reports the effects of different types of radiation on a high-resolution alpha imager, developed using an Electron Multiplying Charge-Coupled Device (EMCCD) camera. The imager was originally designed to visualize Pu oxide particles in decommissioning sites, where other types of radiation such as beta particles, gamma-rays, and neutrons are also present. The measurement of alpha particles, beta particles, gamma-rays, and neutrons were performed, and it was found that the EMCCD camera's sensor detected gamma-rays and neutrons. The discrimination method was based on the characteristics of the image distribution, where the image values were binarized and a Gaussian filter was applied to count the number of alpha particle spots. The results show that it is possible to discriminate between alpha and gamma (neutron) rays using the difference in intensity. The study provides important information for the development of radiation detection techniques in decommissioning sites.
Shikaze, Yoshiaki; Torii, Tatsuo; Nishizawa, Yukiyasu; Yoshida, Mami*; Shimazoe, Kenji*; Jiang, J.*; Takahashi, Hiroyuki*; Kurosawa, Shunsuke*; Kamada, Kei*; Yoshikawa, Akira*; et al.
no journal, ,
no abstracts in English
Shikaze, Yoshiaki; Torii, Tatsuo; Shimazoe, Kenji*; Jiang, J.*; Takahashi, Hiroyuki*; Kurosawa, Shunsuke*; Kamada, Kei*; Yoshikawa, Akira*; Yoshino, Masao*; Ito, Shigeki*; et al.
no journal, ,
no abstracts in English
Kodama, Shohei*; Kurosawa, Shunsuke*; Morishita, Yuki; Usami, Hiroshi; Hayashi, Masateru*; Tanaka, Hiroki*; Yoshino, Masao*; Kamada, Kei*; Yoshikawa, Akira*; Torii, Tatsuo
no journal, ,
After Fukushima 1st Nuclear Plant accident, a large number of radioactive pollutants or nuclear debris with very high dose of more than a few Sv/h still have existed. To estimate the dose of such pollutants, a Japan Atomic Energy Agency research group has suggested a new technique to use a long optical fiber and a red-emitting scintillator, and the scintillation photons are read outside of high dose area. We tested the gamma-ray detection performance of a ruby (Cr:Al
O) and a newly developed CsHfI
scintillators as a scintillating probe coupled with an optical fiber in this study.
Torii, Tatsuo; Sanada, Yukihisa; Kurosawa, Shunsuke*; Hayashi, Takahiro*; Sakagami, Takahide*; Kodama, Shohei*
no journal, ,
In the decommissioning of the Fukushima Daiichi Nuclear Power Plant, non-destructive inspection of piping inside and outside the facility and inspection of contamination inside the piping after removal of the piping is an important issue. In order to set targets for nondestructive inspection inside the piping, we interviewed TEPCO and confirmed the following conditions: the diameters of pipes commonly used in the 1F facility (500A and 25A), hydrogen gas containing 
-ray emitting nuclides, deposits, and moisture inside the pipes. Based on this situation, the two major themes of the research design were nondestructive inspection for internal penetration and radiological imaging. In this series of presentations, we will introduce the research plan and some of the results related to radiation imaging.
Torii, Tatsuo*; Sasaki, Miyuki; Sanada, Yukihisa; Matsubayashi, Nishiki*; Kurosawa, Shunsuke*
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Sasaki, Miyuki; Torii, Tatsuo*; Sanada, Yukihisa; Kurosawa, Shunsuke*; Matsubayashi, Nishiki*
no journal, ,
no abstracts in English
Torii, Tatsuo; Sasaki, Miyuki; Sanada, Yukihisa; Matsubayashi, Nishiki*; Kurosawa, Shunsuke*
no journal, ,
no abstracts in English
Matsubayashi, Nishiki*; Torii, Tatsuo; Sanada, Yukihisa; Kurosawa, Shunsuke*; Sasaki, Miyuki
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no abstracts in English
Enokido, Shunsuke*; Urabe, Kohei; Kurosawa, Itaru*; Kimura, Hiroshi*; Fukaya, Yuji; Sato, Hiroyuki; Sakaba, Nariaki
no journal, ,
Development of heat-resistant concrete to simplify reactor facilities' structures has started to improve the economy of high-temperature gas-cooled reactors. This presentation reports on the development plan, including requirements for heat-resistant concrete for high temperature gas-cooled reactors, candidate concrete specifications meeting these requirements, and the test plan to confirm their technical feasibility.
Sasaki, Miyuki; Torii, Tatsuo*; Kurosawa, Shunsuke*; Matsubayashi, Nishiki*
no journal, ,
no abstracts in English
Matsubayashi, Nishiki*; Torii, Tatsuo*; Sasaki, Miyuki; Kurosawa, Shunsuke*
no journal, ,
no abstracts in English
Asano, Norikazu; Kurosawa, Akihiko; Yanai, Tomohiro; Watahiki, Shunsuke; Kameyama, Yasuhiko; Onoue, Ryuji; Tobita, Kenji; Fukasaku, Akitomi
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no abstracts in English
