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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:62.55(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

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:65.16(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

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:72.44(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

Analysis of $$^{135}$$Cs/$$^{137}$$Cs isotopic ratio for samples used for neutron capture cross section measurement project by thermal ionization mass spectrometry

Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu

JAEA-Conf 2018-001, p.205 - 210, 2018/12

In the ImPACT project, high-precision mass analysis was performed on a $$^{137}$$Cs standard solution for using $$^{135}$$Cs included in the standard solution as an impurity to measure the $$^{135}$$Cs cross-sections. A $$^{137}$$Cs standard solution of only 10Bq (pg order) was analyzed, and the isotope ratio of $$^{135}$$Cs and $$^{137}$$Cs was obtained with an accuracy of 0.5%.

Journal Articles

High-precision mass analysis of RI sample for cross-section measurements

Nakamura, Shoji; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu

KURRI Progress Report 2016, P. 66, 2017/07

In the ImPACT project, high-precision mass analysis was performed on a $$^{137}$$Cs standard solution for using $$^{135}$$Cs included in the standard solution as an impurity to measure the $$^{135}$$Cs cross-sections. A $$^{137}$$Cs standard solution of only 10Bq (pg order) was analyzed, and the isotope ratio of $$^{135}$$Cs and $$^{137}$$Cs was obtained with an accuracy of 0.5%.

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