، صفحه 0-0 (1)

عنوان دوره: اولین دوره بین المللی و بیست و هشتمین دوره ملی (1400)

Thermal neutron absorbers are mainly used around the research reactor experimental facilities to decrease the backgrounds that may affect the experiment results. This study aims to determine an efficient absorber layer within the sample holder tube manufactured for neutron cross-section measurements at the NPD facility of Tehran Research Reactor (TRR). A polyethylene sample holder was simulated in front of the NPD channel using MCNPX code. Since cross-section measurement necessitates a high level of precision, neutron shielding in the vicinity of the sample is probably required to absorb scattered neutrons from interaction with polyethylene. Here, B4C and cadmium layers and also a cadmium shutter have been investigated inside and at the beginning of the sample holder due to their high neutron capture cross-sections and scattering properties. According to the results, both of the proposed layers are effective in reducing relative cross-section discrepancies toward ENDF libraries while cadmium shutter is not required.

Neutron cross-section؛ Absorber layer؛ TRR؛ MCNPX