Measurement of the thermal neutron capture cross section by Be9 using the neutron flux from a nuclear research reactor and the AMS technique

Abstract

We report on the measurement of the thermal neutron capture cross section by $^{9}\mathrm{Be}$, using $^{14}\mathrm{N}$ as a benchmark for the development of our protocol, which implies the combination of two precise techniques: neutron activation in a nuclear research reactor and accelerator mass spectrometry (AMS). Beryllium oxide (BeO), graphite, and uracil (${\mathrm{C}}_{4}{\mathrm{H}}_{4}{\mathrm{N}}_{2}{\mathrm{O}}_{2}$) samples were irradiated at the TRIGA MARK III nuclear research reactor facility at Instituto Nacional de Investigaciones Nucleares (ININ), M\'exico. Later on, isotopic concentrations were quantified by AMS at Laboratorio de Espectrometr\'{\i}a de Masas con Aceleradores (LEMA) of the Instituto de F\'{\i}sica, Universidad Nacional Aut\'onoma de M\'exico (IF-UNAM), Mexico. Cross sections for the $^{9}\mathrm{Be}(n,\ensuremath{\gamma})^{10}\mathrm{Be}$ and $^{14}\mathrm{N}(n,p)^{14}\mathrm{C}$ nuclear reactions were extracted for thermal neutrons.