Thermal-neutron capture cross sections and resonance integrals of the 243Am(n, γ)244gAm and 243Am(n, γ)244m+gAm reactions. Issue 3 (4th March 2021)

• Record Type: Journal Article
• Authors: Nakamura, Shoji; Shibahara, Yuji; Endo, Shunsuke; Kimura, Atsushi
• Is Part Of: Journal of nuclear science and technology. Volume 58:Issue 3(2021)
• Page Start: 259
• Page End: 277
• Publication Date: 2021-03-04
• Subjects: Americium-243 -- americium-244m -- americium-244g -- curium-244 -- thermal-neuron capture cross section resonance integral neutron activation method -- Kyoto university reactor; Nuclear engineering -- Periodicals; Nuclear physics -- Periodicals; Nuclear energy -- Periodicals; 621.4805
• DOI: 10.1080/00223131.2020.1819907
• Languages: English
• ISSNs: 0022-3131

Abstract

ABSTRACT: The thermal-neutron capture cross sections (σ0 ) and resonance integrals (I0 ) were measured for the 243 Am(n, γ) 244g Am and 243 Am(n, γ) 244m+g Am reactions by a neutron activation method. Americium-243 samples were irradiated with a pneumatic tube and a hydraulic conveyer installed in the research reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Alloy wires of Au/Al, Co/Al or Co foils were used as neutron monitors to measure thermal-neutron fluxes and epi-thermal Westcott's indexes at irradiation positions. A 25-μm-thick gadolinium foil was used to separate reactions due to thermal- and epi-thermal neutron components, and a value of 0.133 eV was taken as a corresponding cut-off energy. Gamma-ray spectroscopy was applied to measure radioactivity of neutron monitors and the ground state of reaction products, while alpha-ray spectroscopy was applied to measure that of target 243 Am and final reaction product 244 Cm through the decay of 244m, 244g Am. By utilizing Westcott's convention, the σ0 and I0 values were derived as 4.73 ± 0.27 barn and 96.5 ± 8.9 barn for the 243 Am(n, γ) 244g Am reaction, and 88.5 ± 4.0 barn and 2.30 ± 0.20 kilobarn for the 243 Am(n, γ) 244m+g Am reaction, respectively. The present result of σ0 for the production of 244m+g Am agreed with the reported value of 87.7 ± 5.4 barn measured with a time-of-flight method within the limits of uncertainties.