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Journal Articles

Measurements of neutron capture cross-section for nuclides of interest in decommissioning (II); $$^{58}$$Fe(n,$$gamma$$)$$^{59}$$Fe

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi

Journal of Nuclear Science and Technology, 62(3), p.300 - 307, 2025/03

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

Journal Articles

Measurements of neutron capture cross-section for nuclides of interest in decommissioning (III); $$^{170}$$Er(n,$$gamma$$)$$^{171}$$Er and $$^{180}$$Hf(n,$$gamma$$)$$^{181}$$Hf reactions

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi

Journal of Nuclear Science and Technology, 14 Pages, 2025/00

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

Journal Articles

Measurements of neutron capture cross-sections for nuclides of interest in decommissioning; $$^{45}$$Sc, $$^{63}$$Cu, $$^{64}$$Zn, $$^{109}$$Ag, and $$^{113}$$In

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Rovira Leveroni, G.; Kimura, Atsushi

Journal of Nuclear Science and Technology, 61(11), p.1415 - 1430, 2024/11

 Times Cited Count:1 Percentile:68.64(Nuclear Science & Technology)

Neutron capture cross-sections of nuclides targeted for decommissioning are necessary to contribute to the evaluation of radioactivity produced. The present study, $$^{45}$$Sc, $$^{63}$$Cu, $$^{65}$$Zn, $$^{109}$$Ag and $$^{113}$$In nuclides were selected as target ones, and their thermal-neutron capture cross-sections were measured by an activation method at Kyoto University Research Reactor. The thermal-neutron capture cross-sections were obtained as follows: 27.18$$pm$$0.28 barn for $$^{45}$$Sc(n, $$gamma$$)$$^{46}$$Sc, 4.34$$pm$$0.06 barn for $$^{63}$$Cu(n, $$gamma$$)$$^{64}$$Cu, 0.719$$pm$$0.011 barn for $$^{64}$$Zn(n, $$gamma$$)$$^{65}$$Zn, 4.05$$pm$$0.05 barn for $$^{109}$$Ag(n, $$gamma$$)$$^{rm 110m}$$Ag and 8.53$$pm$$0.27 barn for $$^{113}$$In(n, $$gamma$$) $$^{114}$$In$$^{m1+m2}$$. The results for $$^{45}$$Sc and $$^{64}$$Zn nuclides supported evaluated values within the limits of uncertainties, while those for the other nuclides were slightly different from evaluated ones. The obtained results are useful not only for the evaluation of production amount, but also for the monitor selection other than Au and Co by considering those nuclides as flux monitors.

Journal Articles

Shedding light on the origin of $$^{204}$$Pb, the heaviest $$s$$-process; Only isotope in the solar system

Casanovas-Hoste, A.*; Harada, Hideo; Kimura, Atsushi; 130 of others*

Physical Review Letters, 133(5), p.052702_1 - 052702_8, 2024/07

 Times Cited Count:1 Percentile:58.36(Physics, Multidisciplinary)

Journal Articles

Measurements of the neutron total and capture cross sections and derivation of the resonance parameters of $$^{181}$$Ta

Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto

Nuclear Science and Engineering, 198(4), p.786 - 803, 2024/04

 Times Cited Count:1 Percentile:30.19(Nuclear Science & Technology)

Journal Articles

Measurement of the $$^{140}$$Ce(n, $$gamma$$) cross section at n_TOF and its astrophysical implications for the chemical evolution of the universe

Amaducci, S.*; Harada, Hideo; Kimura, Atsushi; 130 of others*

Physical Review Letters, 132(12), p.122701_1 - 122701_8, 2024/03

 Times Cited Count:2 Percentile:76.47(Physics, Multidisciplinary)

Journal Articles

Measurements of neutron total and capture cross sections of $$^{139}$$La and evaluation of resonance parameters

Endo, Shunsuke; Kawamura, Shiori*; Okudaira, Takuya*; Yoshikawa, Hiromoto*; Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki

European Physical Journal A, 59(12), p.288_1 - 288_12, 2023/12

 Times Cited Count:1 Percentile:30.87(Physics, Nuclear)

no abstracts in English

Journal Articles

Measurements of capture cross-section of $$^{93}$$Nb by activation method and half-life of $$^{94}$$Nb by mass analysis

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi

Journal of Nuclear Science and Technology, 60(11), p.1361 - 1371, 2023/11

 Times Cited Count:3 Percentile:67.98(Nuclear Science & Technology)

The thermal-neutron capture cross section ($$sigma$$$$_{0}$$) and resonance integral (I$$_{0}$$) for $$^{93}$$Nb among nuclides for decommissioning were measured by an activation method and the half-life of $$^{94}$$Nb by mass analysis. Niobium-93 samples were irradiated with a hydraulic conveyer installed in the research reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Gold-aluminum, cobalt-aluminum alloy wires were used to monitor thermal-neutron fluxes and epi-thermal Westcott's indexes at an irradiation position. A 25-$$mu$$m-thick gadolinium foil was used to sort out reactions ascribe to thermal-and epi-thermal neutrons. Its thickness provided a cut-off energy of 0.133 eV. In order to attenuate radioactivity of $$^{182}$$Ta due to impurities, the Nb samples were cooled for nearly 2 years. The induced radio activity in the monitors and Nb samples were measured by $$gamma$$-ray spectroscopy. In analysis based on Westcott's convention, the $$sigma$$$$_{0}$$ and I$$_{0}$$ values were derived as 1.11$$pm$$0.04 barn and 10.5$$pm$$0.6 barn, respectively. After the $$gamma$$-ray measurements, mass analysis was applied to the Nb sample to obtain the reaction rate. By combining data obtained by both $$gamma$$-ray spectroscopy and mass analysis, the half-life of $$^{94}$$Nb was derived as (2.00$$pm$$0.15)$$times$$10$$^{4}$$ years.

Journal Articles

Measurement of the $$^{77}$$Se(n,$$gamma$$) cross section up to 200 keV at the n_TOF facility at CERN

Sosnin, N. V.*; Harada, Hideo; Kimura, Atsushi; 128 of others*

Physical Review C, 107(6), p.065805_1 - 065805_9, 2023/06

 Times Cited Count:0 Percentile:0.00(Physics, Nuclear)

Journal Articles

$$^{74}$$Ge(n,$$gamma$$) cross section below 70 keV measured at n_TOF CERN

Lederer-Woods, C.*; Harada, Hideo; Kimura, Atsushi; 128 of others*

European Physical Journal A, 58(12), p.239_1 - 239_9, 2022/12

 Times Cited Count:0 Percentile:0.00(Physics, Nuclear)

Journal Articles

Thermal-neutron capture cross-section measurements of neptunium-237 with graphite thermal column in KUR

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi

Journal of Nuclear Science and Technology, 59(11), p.1388 - 1398, 2022/11

 Times Cited Count:1 Percentile:16.36(Nuclear Science & Technology)

The present study selected $$^{237}$$Np among radioactive nuclides and aimed to measure the thermal-neutron capture cross-section for $$^{237}$$Np in a well-thermalized neutron field by an activation method. A $$^{237}$$Np standard solution was used for irradiation samples. A thermal-neutron flux at an irradiation position was measured with neutron flux monitors: $$^{45}$$Sc, $$^{59}$$Co, $$^{98}$$Mo, $$^{181}$$Ta and $$^{197}$$Au. The $$^{237}$$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 $$^{237}$$Np samples were quantified using 312-keV gamma ray emitted from $$^{233}$$Pa in a radiation equilibrium with $$^{237}$$Np. The reaction rates of $$^{237}$$Np were obtained from gamma-ray peak net counts given by $$^{238}$$Np, and then the thermal-neutron capture cross-section of $$^{237}$$Np was found to be 173.8$$pm$$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.

Journal Articles

Measurements of thermal-neutron capture cross-section of the $$^{237}$$Np(n, $$gamma$$) reaction with TC-Pn in KUR

Nakamura, Shoji; Endo, Shunsuke; Kimura, Atsushi; Shibahara, Yuji*

KURNS Progress Report 2021, P. 93, 2022/07

In terms of nuclear transmutation studies of minor actinides in nuclear wastes, the present work selected $$^{237}$$Np among them and aimed to measure the thermal-neutron capture cross-section of $$^{237}$$Np using a well-thermalized neutron field by a neutron activation method because there have been discrepancies among reported cross-section data. A $$^{237}$$Np standard solution was used for irradiation samples. The thermal-neutron flux at an irradiation position was measured with flux monitors: $$^{45}$$Sc, $$^{59}$$Co, $$^{98}$$Mo, $$^{181}$$Ta and $$^{197}$$Au. The $$^{237}$$Np sample was irradiated together with the flux monitors for 30 minutes in the graphite thermal column equipped in the Kyoto University Research Reactor. The similar irradiation was repeated once more to confirm the reproducibility of the results. After irradiation, the $$^{237}$$Np samples were quantified using 312-keV gamma-ray emitted from $$^{233}$$Pa in radiation equilibrium with $$^{237}$$Np. The reaction rates of $$^{237}$$Np were obtained from the peak net counts of gamma-rays emitted from generated $$^{238}$$Np, and then the thermal-neutron capture cross-section of $$^{237}$$Np was found to be 173.8$$pm$$4.7 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 a limit of uncertainty.

Journal Articles

Neutron capture and total cross-section measurements and resonance parameter analysis of niobium-93 below 400 eV

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

 Times Cited Count:8 Percentile:69.17(Nuclear Science & Technology)

Journal Articles

KeV-region analysis of the neutron capture cross-section of $$^{237}$$Np

Rovira Leveroni, G.; Katabuchi, Tatsuya*; Tosaka, Kenichi*; Matsuura, Shota*; Kodama, Yu*; Nakano, Hideto*; Iwamoto, Osamu; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki

Journal of Nuclear Science and Technology, 59(1), p.110 - 122, 2022/01

 Times Cited Count:5 Percentile:51.35(Nuclear Science & Technology)

Journal Articles

Thermal-neutron capture cross-section measurement of tantalum-181 using graphite thermal column at KUR

Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi

Journal of Nuclear Science and Technology, 58(10), p.1061 - 1070, 2021/10

 Times Cited Count:9 Percentile:73.48(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: $$^{197}$$Au, $$^{59}$$Co, $$^{45}$$Sc, $$^{63}$$Cu, and $$^{98}$$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 $$^{181}$$Ta(n,$$gamma$$)$$^{182m+g}$$Ta reaction was measured using the graphite thermal column, and then derived to be 20.5$$pm$$0.4 barn, which supported the evaluated value of 20.4$$pm$$0.3 barn. The $$^{181}$$Ta nuclide could be useful as a flux monitor that complements the sensitivity between $$^{197}$$Au and $$^{98}$$Mo monitors.

Journal Articles

Measurement of the $$^{76}$$Ge(n,$$gamma$$) cross section at the n_TOF facility at CERN

Gawlik, A.*; Harada, Hideo; Kimura, Atsushi; 130 of others*

Physical Review C, 104(4), p.044610_1 - 044610_7, 2021/10

 Times Cited Count:5 Percentile:53.57(Physics, Nuclear)

Journal Articles

Bias effects on g- and s-factors in Westcott convention

Harada, Hideo

Applied Sciences (Internet), 11(14), p.6558_1 - 6558_20, 2021/07

 Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)

For accuracy improvement of neutron activation analysis and neutron capture cross section, bias effects are investigated on g- and s-factors in the Westcott convention. As origins of biases, a joining function shape, neutron temperature and sample temperature, have been investigated. Biases are quantitatively deduced for two 1/v isotopes ($$^{197}$$Au, $$^{59}$$Co) and six non-1/v isotopes ($$^{241}$$Am, $$^{151}$$Eu, $$^{103}$$Rh, $$^{115}$$In, $$^{177}$$Hf, $$^{226}$$Ra). The s-factor calculated with a joining function deduced recently by a detailed Monte Carlo simulation is compared to s-factors calculated with traditional joining functions by Westcott. The results show the bias induced by sample temperature is small as the order of 0.1% for g-factor and the order of 1% for s-factor. On the other hand, biases induced by a joining function shape for s-factor depend significantly on both isotopes and neutron temperature. As the result, reaction rates are also affected significantly as well. The bias size on reaction rate is given in the case of epithermal neutron index r = 0.1, for the eight isotopes.

Journal Articles

Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC

Kawase, Shoichiro*; Kimura, Atsushi; Harada, Hideo; Iwamoto, Nobuyuki; Iwamoto, Osamu; Nakamura, Shoji; Segawa, Mariko; Toh, Yosuke

Journal of Nuclear Science and Technology, 58(7), p.764 - 786, 2021/07

 Times Cited Count:4 Percentile:42.67(Nuclear Science & Technology)

Journal Articles

First results of the $$^{140}$$Ce(n,$$gamma$$)$$^{141}$$Ce cross-section measurement at n_TOF

Amaducci, S.*; Harada, Hideo; Kimura, Atsushi; 127 of others*

Universe (Internet), 7(6), p.200_1 - 200_11, 2021/06

 Times Cited Count:5 Percentile:34.51(Astronomy & Astrophysics)

Journal Articles

Measurement of the $$^{72}$$Ge(n,$$gamma$$) cross section over a wide neutron energy range at the CERN n_TOF facility

Dietz, M.*; Harada, Hideo; Kimura, Atsushi; 121 of others*

Physical Review C, 103(4), p.045809_1 - 045809_8, 2021/04

 Times Cited Count:6 Percentile:60.24(Physics, Nuclear)

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