Measurement of Effective Capture Cross Section of Americium-243 for Thermal Neutrons

Abstract

The effective capture cross section of 243 Am for thermal neutrons was measured with an activation method. A sample of 243 Am was irradiated for 10 hrs at Kyoto University Reactor, KUR. After the irradiation, the sample was cooled for one month. In the cooling time, 244m Am and 244g Am produced by the irradiation decayed out to 244 Cm. The rays emitted from 243 Am and 244 Cm were measured with a silicon surface barrier detector. The neutron flux at the irradiation position was monitored using Au/Al and Co/Al wires. The effective capture cross section was deduced as 174:5AE5:3b from the-ray counts and the neutron flux. The quantity r ffiffiffiffiffiffiffiffiffiffi T=T 0 p in Westcott's convention was 0:037AE0:004. The present result was compared with the effective capture cross sections from the JENDL-3.3 and the Mughabghab evaluations.

Thermal-Neutron Capture Cross Section and Resonance Integral of Americium-241

“…fractions in the neutron flux. 16,17) The amount of Co or Au contained in each wire was determined by weight measurement with a microbalance. Nuclear data 1,18,19) for monitor wires are listed in Table 2.…”

“…The effective cross section is defined by equating the reaction rate R to the product of and n 0 , where n 0 16,17) is the ''neutron flux'' in Westcott's convention 20) with the neutron density n, including thermal and epithermal neutrons, and with the velocity of neutrons 0 ¼ 2;200 m/s, so that…”

Nuclear Back-end and Transmutation Technology for Waste Disposal

“…Neutron capture cross sections were determined on the basis of Westcott's convention [1] by an activation method. The results for LLFPs are listed in Table 5.1, and for MAs [24][25][26][27][28][29][30][31] in Table 5.2, together with previously reported data. Here, the symbols σ eff , σ 0 , and I 0 denote the effective cross section, the thermal neutron capture cross section, and the resonance integral, respectively; σ 0 is the cross section at the neutron energy of 25.3 meV.…”

Precise Measurements of Neutron Capture Cross Sections for LLFPs and MAs

“…The results for LLFPs are listed in Table 5.1, and for MAs [24][25][26][27][28][29][30][31] in Table 5.2, together with previously reported data. Here, the symbols σ eff , σ 0 , and I 0 denote the effective cross section, the thermal neutron capture cross section, and the resonance integral, respectively; σ 0 is the cross section at the neutron energy of 25.3 meV.…”