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Nakamura, Shoji; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi; Shibahara, Yuji*
KURNS Progress Report 2023, P. 46, 2024/07
The present work is an attempt to measure the thermal-neutron capture cross-sections for some nuclides which are of importance in decommissioning to evaluate produced radioactivity. This work selected some of objective nuclides for decommissioning, such as Fe, Er and Hf, and measured thermal-neutron capture cross-sections for these nuclides by a neutron activation method at Kyoto University Research Reactor. The present results were obtained as follows:1.230.03 barn for Fe(n,)Fe reaction, 8.190.35 barn for Er(n,)Er reaction and 13.570.14 barn for Hf(n,)Hf reaction. As a by-product, the measurement of Hf sample also presented 0.4270.006 barn for Hf(n,)mHf reaction. It has been revealed that the data adopted in an evaluated data library differ from the present results by more than experimental uncertainties.
Katabuchi, Tatsuya*; Sato, Yaoki*; Takebe, Karin*; Igashira, Masayuki*; Umezawa, Seigo*; Fujioka, Ryo*; Saito, Tatsuhiro*; Iwamoto, Nobuyuki
Journal of Nuclear Science and Technology, 61(2), p.224 - 229, 2024/02
Times Cited Count:0 Percentile:0.05(Nuclear Science & Technology)Nakamura, Shoji; Endo, Shunsuke; Kimura, Atsushi; Shibahara, Yuji*
KURNS Progress Report 2022, P. 73, 2023/07
The present study is concerned with the neutron capture cross-sections that contribute to the evaluation of the amount of radionuclides possessing problems in decommissioning. In this study, Sc, Cu, Zn, Ag, In and W were selected among the objective nuclides, and their thermal-neutron capture cross-sections were measured using TC-Pn equipment of the KUR of the Institute for Integrated Radiation and Nuclear Science, Kyoto University. High purity metal samples were prepared. A gold-aluminum ally wire, cobalt and molybdenum foils were used to monitor the neutron flux at the irradiation position of TC-Pn. The flux monitors and metal samples were irradiated for 1 hour at 1-MW operation of the KUR. After irradiation, the irradiation capsule was opened, samples and flux monitors were enclosed in a vinyl bag one by one, and then rays emitted from the samples and monitors were measured with a high-purity Ge detector. The thermal-neutron flux component was derived with the reaction rates of flux monitors (Au, Co and Mo) on the basis of Westcott's convention, and found to be (5.920.10)10 n/cm/sec at the irradiation position. The measured reaction rate for each metal sample divided by the evaluated thermal-neutron capture cross-section should give the same value of the thermal-neutron flux component if the cross section is suitable. This time, we found that the cross sections of Sc and Zn were consistent with the evaluated one, but those of other nuclides were inconsistent with their evaluated ones; that is, it turned out that their thermal-neutron capture cross-sections should be modified.
Nauchi, Yasushi*; Sato, Shunsuke*; Hayakawa, Takehito*; Kimura, Yasuhiko; Suyama, Kenya; Kashima, Takao*; Futakami, Kazuhiro*
Nuclear Instruments and Methods in Physics Research A, 1050, p.168109_1 - 168109_9, 2023/05
Times Cited Count:0 Percentile:0.02(Instruments & Instrumentation)Measurement of neutrons from spent nuclear fuel is performed in this study using the H method, which detects 2.223 MeV rays from neutron capture reaction of hydrogen using a highly pure germanium (HPGe) detector. The detection of the 2.223 MeV ray is affected by intense ray emission from fission products (FPs) because the emission rate of rays from the FP is seven orders of magnitude higher than the emission rate of neutrons. To shield the intense ray from the FP, the HPGe detector is placed off the axis of a collimator, whereas a polyethylene block is placed on the axis. In this geometry, the detector is shielded from the intense rays from the FP, but the detector can measure 2.223 MeV rays from the H reactions in the polyethylene block. The measured count rate of the 2.223 MeV rays is consistent with the expected rate within the statistical error, which is calculated based on the nuclide composition, which is primary Cm, estimated via depletion and decay calculations. Accordingly, the H method is considered feasible to quantify the number of neutron leakage from spent nuclear fuel assembly, which is applicable to certify burn up of the assembly.
Segawa, Mariko; Toh, Yosuke; Kai, Tetsuya; Kimura, Atsushi; Nakamura, Shoji
Annals of Nuclear Energy, 167, p.108828_1 - 108828_5, 2022/03
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)Nakamura, Shoji; Hatsukawa, Yuichi*; Kimura, Atsushi; Toh, Yosuke; Harada, Hideo
Journal of Nuclear Science and Technology, 58(12), p.1318 - 1329, 2021/12
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)The present study performed fast-neutron capture cross-section measurement of Tc by an activation method using a fast-neutron source reactor "YAYOI" of the University of Tokyo. Technetium-99 samples were irradiated with reactor neutrons using a pneumatic system. Reaction rates of Tc were obtained by measuring decay gamma rays emitted from Tc. The neutron flux at an irradiation position was monitored with gold foils. The fast-neutron capture cross section of Tc at neutron energy of 85 keV was derived as 0.4320.023 barn by using the reaction rates of Tc, evaluated cross-section data and the fast-neutron flux spectrum of the YAYOI reactor. The present study agreed with the evaluated nuclear data library JENDL-4.0.
Bhattacharyya, A.*; Datta, U.*; Rahaman, A.*; Chakraborty, S.*; Aumann, T.*; Beceiro-Novo, S.*; Boretzky, K.*; Caesar, C.*; Carlson, B. V.*; Catford, W. N.*; et al.
Physical Review C, 104(4), p.045801_1 - 045801_14, 2021/10
Times Cited Count:5 Percentile:62.78(Physics, Nuclear)no abstracts in English
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.
Katabuchi, Tatsuya*; Toh, Yosuke; Mizumoto, Motoharu*; Saito, Tatsuhiro*; Terada, Kazushi*; Kimura, Atsushi; Nakamura, Shoji; Huang, M.*; Rovira Leveroni, G.; Igashira, Masayuki*
European Physical Journal A, 57(1), p.4_1 - 4_4, 2021/01
Times Cited Count:3 Percentile:44.64(Physics, Nuclear)Katabuchi, Tatsuya*; Iwamoto, Osamu; Hori, Junichi*; Kimura, Atsushi; Iwamoto, Nobuyuki; Nakamura, Shoji; Shibahara, Yuji*; Terada, Kazushi*; Rovira, G.*; Matsuura, Shota*
EPJ Web of Conferences, 239, p.01044_1 - 01044_4, 2020/09
Times Cited Count:2 Percentile:86.21(Nuclear Science & Technology)Prez Snchez, R.*; Jurado, B.*; Mot, V.*; Roig, O.*; Dupuis, M.*; Bouland, O.*; Denis-Petit, D.*; Marini, P.*; Mathieu, L.*; Tsekhanovich, I.*; et al.
Physical Review Letters, 125(12), p.122502_1 - 122502_5, 2020/09
Times Cited Count:14 Percentile:72.90(Physics, Multidisciplinary)Katabuchi, Tatsuya*; Iwamoto, Osamu; Hori, Junichi*; Iwamoto, Nobuyuki; Kimura, Atsushi; Nakamura, Shoji; Shibahara, Yuji*; Terada, Kazushi*
JAEA-Conf 2019-001, p.193 - 197, 2019/11
Nakamura, Shoji; Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Takamiya, Koichi*; Fujii, Toshiyuki*
Journal of Nuclear Science and Technology, 56(1), p.123 - 129, 2019/01
Times Cited Count:1 Percentile:10.65(Nuclear Science & Technology)Accurate data of -ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by -ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces Am after neutron capture. The 744-keV -ray decaying from the ground state of Am has a relatively large -ray emission probability c.a. 66%, however, its uncertainty is as large as 29%. The uncertainty of the -ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the -ray emission probability was measured by using an activation method and an examined level structure of Cm. In this study, the emission probability of 744-keV ray was derived as 66.51.1%, and its uncertainty was improved from 29% to 2%.
Hirose, Kentaro; Nishio, Katsuhisa; Makii, Hiroyuki; Nishinaka, Ichiro*; Ota, Shuya*; Nagayama, Tatsuro*; Tamura, Nobuyuki*; Goto, Shinichi*; Andreyev, A. N.; Vermeulen, M. J.; et al.
Nuclear Instruments and Methods in Physics Research A, 856, p.133 - 138, 2017/06
Times Cited Count:5 Percentile:43.75(Instruments & Instrumentation)Hales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu
J-PARC 17-07; J-PARC MLF Annual Report 2016, p.88 - 89, 2017/03
Kitatani, Fumito
Kaku Deta Nyusu (Internet), (114), p.44 - 49, 2016/06
no abstracts in English
Nakamura, Shoji; Kimura, Atsushi; Toh, Yosuke; Harada, Hideo; Katabuchi, Tatsuya*; Mizumoto, Motoharu*; Igashira, Masayuki*; Hori, Junichi*; Kino, Koichi*
JAEA-Conf 2015-003, p.113 - 118, 2016/03
Experiments were carried out with the Ge detector of ANNRI to confirm whether or not the weak resonances were surely due to Pd. The prompt rays due to capture reaction of Pd were clearly observed at the -ray energy at 115 kev and around 300 keV. When a TOF spectrum was extracted by gating at the prompt ray around 300 keV, the small resonance peaks were revealed at the neutron energy of 146 and 156 eV.
Kimura, Atsushi; Harada, Hideo; Nakamura, Shoji; Iwamoto, Osamu; Toh, Yosuke; Koizumi, Mitsuo; Kitatani, Fumito; Furutaka, Kazuyoshi; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.
European Physical Journal A, 51(12), p.180_1 - 180_8, 2015/12
Times Cited Count:3 Percentile:30.26(Physics, Nuclear)Katabuchi, Tatsuya*; Yanagida, Shotaro*; Terada, Kazushi; Iwamoto, Nobuyuki; Igashira, Masayuki*
EPJ Web of Conferences, 93, p.02008_1 - 02008_2, 2015/05
Times Cited Count:0 Percentile:0.16(Physics, Multidisciplinary)Ba has the smallest neutron capture cross section among the stable Ba isotopes. The neutron capture reaction of Ba is dominated by resolved resonances in the astrophysically relevant energy region. Thus, reliable experimental data of the capture cross section are necessary. In the present work, we measured the neutron capture cross section of Ba in the energy region from 15 to 100 keV by the time-of-flight method at the Tokyo Institute of Technology. The capture cross sections were obtained from the pulse height spectra by the pulse-height weighting technique. A comparison of the present results with previous experimental data and evaluated data was made. We also derived -ray spectra by unfolding the pulse height spectra. It was revealed that the shape of -ray spectra strongly depends on neutron energy.
Harada, Hideo
Kaku Deta Nyusu (Internet), (109), p.44 - 47, 2014/10
Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program". The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the research project team aims at improving the accuracy of the data. The background, goal and brief research plan of the AIMAC project are explained.