Sensitivity Analysis of an Advanced Transmission Measurement Method for Thermal Neutrons Absorbers Detection in Irradiated Beryllium

This paper presents an advanced optimization analysis of the newly developed transmission measurement method conducted in the MARIA MTR reactor for thermal neutrons absorbers estimation in irradiated beryllium elements. Several neutron sources in combination with various thermal neutron detectors are investigated, along with the optimization of the moderating polyethylene layer to improve the signal to background ratio. It was concluded that the use of 239 PuBe or 241 AmB neutron source with polyethylene of 0.95 g/cm 3 density and ∼4.5 cm thickness, as well as either 235 U lined fission chamber or BF 3 detectors are meeting the requirements for the use in the experiment.