Activation analysis of high-purity silicon

Neutron capture cross section measurements and theoretical calculation for the 186W(n,γ)187W reaction

Neutron capture cross section (σ 0) and resonance integral (I 0) of the reaction 186W(n,γ)187W were measured experimentally using the research reactor (ETRR-2) and an Am–Be neutron source, also calculated using TALYS-1.6 code. The present results of σ 0 are (39.08±2.6, 38.75±0.98 and 38.33 barn) and I 0 are (418.5±74, 439.3±36 and 445.5 barn) by using the reactor, neutron source and TALYS-1.6, respectively. The present results are in acceptable agreement with most of the previous experimental and evaluated data as well as the theoretical calculations.

41K(n,γ)42K thermal and resonance integral cross section measurements

We measured the41K thermal neutron absorption and resonance integral cross sections after the irradiation of KNO3samples near the core of the IEA-R1 IPEN pool-type research reactor. Bare and cadmium-covered targets were irradiated in pairs with Au-Al alloy flux-monitors. The residual activities were measured by gamma-ray spectroscopy with a HPGe detector, with special care to avoid the42K decayβ-emission effects on the spectra. The gamma-ray self-absorption was corrected with the help of MCNP simulations. We applied the Westcott formalism in the average neutron flux determination and calculated the depression coefficients for thermal and epithermal neutrons due to the sample thickness with analytical approximations. We obtained 1.57(4) b and 1.02(4) b, for thermal and resonance integral cross sections, respectively, with correlation coefficient equal to 0.39.