Speaker
Description
A new setup is being prepared in Centrum Výzkumu Řež for the measurement of prompt capture and inelastic gammas coming from neutron interactions. These gammas are important for safety during reactor operations (worker’s protection or radiation damage) or have applications in many areas like element identification in soil and space.
The setup consists of an aluminum sphere with a 50 cm diameter filled with liquid target material – usually different materials dissolved in demineralized water. Prompt gamma radiation is excited by a well-defined 252Cf spontaneous fission source or AmBe source. 252Cf source, with lower average neutron energy, is more suitable for prompt capture gamma (due to the high cross-section in thermal energies), and the AmBe source is more suitable for inelastic scattering. The gamma spectrum is measured by a well-defined HPGe detector and scintillation detector. HPGe detector is shielded by borated polyethylene, cadmium, and enriched 6Li shielding plate to prevent radiation damage from neutrons. A lead shield can be present to suppress prompt capture gammas from shielding and to suppress low gamma background. Both neutron and gamma transport are simulated using MCNP6.2 code. The HPGe efficiency curve is determined using MCNP6.2 and experimentally determined HPGe parameters. The source term of studied prompt gammas is tested using various nuclear data libraries. The scintillation detector is used for testing the HPGe shielding. It is worth noting that the first tests of validation of 16O inelastic scattering gamma using the well-defined AmBe source show discrepancy up to 90% for ENDF/B-VII.1.