Multi-parameter optimization of a (³He-²⁵²Cf-³He) neutron backscattering sensor for land mine detection

Experimental measurements were carried out to optimize the performance of a (³He-²⁵²Cf-³He) assembly for plastic anti-personnel land mine detection in dry soils. This is done by employing a²⁵²Cf source producing 0.7×10⁴ n.s^-1and a pair of two identical ³He detectors. The Signal-to-background ratio due to the responses of the two ³He detectors is monitored and analyzed as a function of detector-detector distance, stand-off distance, mine depth and source position while scanning the mine.The laboratory measurements were followed by Monte Carlo simulations to explore the capabilities of the laboratory measurements in the presence of ²⁵²Cf sources producing 10⁴ n.s^-1and 10⁶ n.s^-1. The optimal ²⁵²Cf source was selected and employed in further Monte Carlo simulations to study the impact of a multi-layer shield on the performance of the (³He-²⁵²Cf-³He) assembly