Ascertaining directionality information from incident nuclear radiation

Unprecedented capabilities for the detection of nuclear particles via tailored resonant acoustic systems such as the acoustic tensioned metastable fluid detection (ATMFD) systems were assessed for determining directionality of incoming fast neutrons. This paper presents advancements that expand on these accomplishments, thereby increasing the accuracy and precision of ascertaining directionality information utilizing enhanced signal processing-cum-signal analysis, refined computational algorithms, and on demand enlargement of the detector sensitive volume. Advances in the development of ATMFD systems were accomplished utilizing a combination of experimentation and theoretical modeling. Modeling methodologies include Monte-Carlo based nuclear particle transport using MCNP5 and multi-physics based assessments accounting for acoustic, structural, and electromagnetic coupling of the ATMFD system via COMSOL's multi-physics simulation platform. Benchmarking and qualification studies have been conducted with a 1 Ci Pu–Be neutron-gamma source. These results show that the specific ATMFD system used for this study can enable detection of directionality of incoming fast neutrons from the neutron source to within 30° with 80% confidence; this required ∼2000 detection events which could be collected within ∼50 s at a detection rate of ∼30–40 per second. Blind testing was successfully conducted for determining the neutron source randomly positioned in space. Results of experimentation were found to be compatible with MCNP5-COMSOL multi-physics model predictions.

► Use of tensioned metastable fluids for detection of fast neutron radiation.
► Monitored neutrons with 100% gamma photon blindness capability.
► Monitored direction of incoming neutron radiation from special nuclear material emissions.
► Ascertained directionality of neutron source to within 30° and with 80% confidence with 2000 detection events at rate of 30–40 per second.
► Conducted successful blind test for determining source of neutrons from a hidden neutron emitting source.
► Compared results with MCNP5-COMSOL based multi-physics model.