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Maeda, Makoto; Segawa, Mariko; Toh, Yosuke; Endo, Shunsuke; Nakamura, Shoji; Kimura, Atsushi
Scientific Reports (Internet), 12(1), p.6287_1 - 6287_8, 2022/06
Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Sato, Yaoki*; et al.
Journal of Nuclear Science and Technology, 59(5), p.647 - 655, 2022/05
Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi
Journal of Nuclear Science and Technology, 11 Pages, 2022/04
The present study selected Np among radioactive nuclides and aimed to measure the thermal-neutron capture cross-section for
Np in a well-thermalized neutron field by an activation method. A
Np standard solution was used for irradiation samples. A thermal-neutron flux at an irradiation position was measured with neutron flux monitors:
Sc,
Co,
Mo,
Ta and
Au. The
Np sample and flux monitors were irradiated together for 30 minutes in the graphite thermal column equipped with the Kyoto University Research Reactor. The similar irradiation was carried out twice. After the irradiations, the
Np samples were quantified using 312-keV gamma ray emitted from
Pa in a radiation equilibrium with
Np. The reaction rates of
Np were obtained from gamma-ray peak net counts given by
Np, and then the thermal-neutron capture cross-section of
Np was found to be 173.8
4.4 barn by averaging the results obtained by the two irradiations. The present result was in agreement with the reported data given by a time-of-flight method within the limit of uncertainty.
Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Terada, Kazushi*; Meigo, Shinichiro; Toh, Yosuke; Segawa, Mariko; et al.
Journal of Nuclear Science and Technology, 59(3), p.318 - 333, 2022/03
Kodama, Yu*; Katabuchi, Tatsuya*; Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Nobuyuki; Iwamoto, Osamu; Hori, Junichi*; Shibahara, Yuji*; et al.
Journal of Nuclear Science and Technology, 58(11), p.1159 - 1164, 2021/11
Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi
Journal of Nuclear Science and Technology, 58(10), p.1061 - 1070, 2021/10
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)In a well-thermalized neutron field, it is principally possible to drive a thermal-neutron capture cross-section without considering an epithermal neutron component. This was demonstrated by a neutron activation method using the graphite thermal column (TC-Pn) of the Kyoto University Research Reactor. First, in order to confirm that the graphite thermal column was a well-thermalized neutron field, neutron irradiation was performed with neutron flux monitors: Au,
Co,
Sc,
Cu, and
Mo. The TC-Pn was confirmed to be extremely thermalized on the basis of Westcott's convention, because the thermal-neutron flux component took a constant value regardless of the sensitivity of each flux monitor to epithermal neutrons. Next, as a demonstration, the thermal-neutron capture cross section of
Ta(n,
)
Ta reaction was measured using the graphite thermal column, and then derived to be 20.5
0.4 barn, which supported the evaluated value of 20.4
0.3 barn. The
Ta nuclide could be useful as a flux monitor that complements the sensitivity between
Au and
Mo monitors.
Nakamura, Shoji; Endo, Shunsuke; Kimura, Atsushi; Shibahara, Yuji*
KURNS Progress Report 2020, P. 94, 2021/08
The present study selected Np among radioactive nuclides and aimed to converge a contradiction between reported thermal-neutron capture cross sections. Neutron irradiation was carried out using the graphite thermal column equipped with the Kyoto University Research Reactor. A solution equivalent to 950 Bq order of radioactivity was pipetted out of a
Np standard solution and dropped onto a fiber filter, which was then dried with an infrared lamp to prepare a
Np sample. The
Np sample was quantified using 312-keV gamma ray emitted from
Pa in a radiation equilibrium with
Np. To monitor a thermal-neutron flux component at an irradiation position, the
Np sample was irradiated together with several stable nuclides as neutron flux monitors:
Sc,
Co,
Mo,
Ta and
Au. The reaction rate of
Np was obtained from gamma-ray yields given by
Np and
Pa, and then the thermal-neutron capture cross section of
Np was derived.
Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Ebihara, Mitsuru*
Analytical Chemistry, 93(28), p.9771 - 9777, 2021/07
Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Terada, Kazushi*; Kodama, Yu*; Nakano, Hideto*; et al.
Nuclear Instruments and Methods in Physics Research A, 1003, p.165318_1 - 165318_10, 2021/07
Times Cited Count:0 Percentile:0.03(Instruments & Instrumentation)Okudaira, Takuya*; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Ninomi, Yudai*; Sakai, Kenji; et al.
Physical Review C, 104(1), p.014601_1 - 014601_6, 2021/07
Times Cited Count:0 Percentile:0.03(Physics, Nuclear)Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi
Journal of Nuclear Science and Technology, 58(3), p.259 - 277, 2021/03
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)Research and development were made for accuracy improvement of neutron capture cross section data on Am among minor actinides. First, the emission probabilities of decay
rays were obtained with high accuracy, and the amount of the ground state of
Am produced by reactor neutron irradiation of
Am was examined by
-ray measurement. Next, the total amount of isomer and ground states was examined by
-ray measurement. Thermal-neutron capture cross sections and resonance integrals were derived both for the
Am(n,
)
Am and for
Am(n,
)
Am reactions.
Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.
Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10
Times Cited Count:4 Percentile:76.41(Instruments & Instrumentation)Nakamura, Shoji; Endo, Shunsuke; Kimura, Atsushi; Shibahara, Yuji*
KURNS Progress Report 2019, P. 132, 2020/08
Research and development were made for accuracy improvement of neutron capture cross section data on Am among minor actinides. First, the emission probabilities of decay
rays were obtained with high accuracy, and the amount of the ground state of
Am produced by reactor neutron irradiation of
Am was examinded by
-ray measurement. Next, the total amount of isomer and ground states was examoned by
-ray measurement.
Okudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.
EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12
Parity violating effects enhanced by up to 10 times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,
) reaction was measured with
La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized
La target and a 70% polarized
He spin filter whose thickness is 70 atm
cm are needed. Therefore high quality
He spin filter is developed in JAEA. The measurement result of the (n,
) reaction at J-PARC and the development status of the
He spin filter will be presented.
Shikaze, 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:24 Percentile:96.18(Nuclear Science & Technology)The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 44 to 8
8 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
).
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
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
Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*
no journal, ,
Niobium (Nb)-93, which is mono isotope, is one of the material elements to strengthen stainless steel and is used for structural materials of nuclear reactors. Since Nb is also used as an element of superconductor alloys, it has been used in fields such as fusion reactor and accelerator development. Determination of neutron total cross section with high accuracy is therefore required in the field of nuclear technology. The cross sections of Nb were measured by T. Wang (2011), N. J. Drindak (2006) and so on. However, the resonance parameters determined by them have discrepancies up to about 10% each other. In order to determine the more precise values of resonance parameters, transmission measurements were performed to evaluate total cross section of Nb-93 at the ANNRI of MLF in J-PARC in June of 2019. The ANNRI is one of beamlines in MLF, and Germanium gamma-ray detectors and the Liglass neutron detectors are installed to measure nuclear reactions. A target was natural Nb plate of 25 mm 25 mm
10 mm
whose size was determined from necessary statistic. Since the target size was big and the thermal-neutron capture cross-section is small (about 1.1 barns), the effect of neutron diffraction was observed in low neutron energy region. When discussing reactions to a single nucleus, the effect of diffraction resulting from crystal structure is unnecessary information. Thus, this effect must be estimated and removed to determine the total cross section as nuclear data for a single nucleus. In this poster, I will present preliminary results of the experiment and the estimated effects of neutron diffraction. This work has been supported in part by Grants-in-Aid for Scientific Research (JP17H01076).
Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi
no journal, ,
Research and development were made for accuracy improvement of neutron capture cross-section data on Am among minor actinides. First, the emission probabilities of decay
-rays were obtained with high accuracy, and the amount of the ground state of
Am produced by reactor neutron irradiation of
Am was examinded by
-ray measurement. Next, the total amount of isomer and ground states was examoned by
-ray measurement. This presentation will give the details of the measurenmets and the results of the neutron capture cross-sections of
Am.
Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*
no journal, ,
no abstracts in English