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Nakamura, Shoji; Shibahara, Yuji*; Endo, Shunsuke; Kimura, Atsushi
Journal of Nuclear Science and Technology, 59(11), p.1388 - 1398, 2022/11
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)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.
Nakamura, Shoji; Kitatani, Fumito; Kimura, Atsushi; Uehara, Akihiro*; Fujii, Toshiyuki*
Journal of Nuclear Science and Technology, 56(6), p.493 - 502, 2019/06
Times Cited Count:5 Percentile:57.06(Nuclear Science & Technology)The thermal-neutron capture cross-section()and resonance integral(I
) were measured for the
Np(n,
)
Np reaction by an activation method. A method with a Gadolinium filter, which is similar to the Cadmium difference method, was used to measure the
with paying attention to the first resonance at 0.489 eV of
Np, and a value of 0.133 eV was taken as a cut-off energy. Neptunium-237 samples were irradiated at the pneumatic tube of the Kyoto University Research Reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Wires of Co/Al and Au/Al alloys were used as monitors to determine thermal-neutron fluxes and epi-thermal Westcott's indices at an irradiation position. A
-ray spectroscopy was used to measure activities of
Np,
Np and neutron monitors. On the basis of Westcott's convention, the
and I
values were derived as 186.9
6.2 barn, and 1009
90 barn, respectively.