Recent results from thin-film-coated semiconductor neutron detectors

Abstract

Semiconductor based thermal neutron detectors provide a compact technology for neutron detection and imaging. Such devices can be produced by externally coating semiconductor charged particle detectors with neutron reactive films that convert free neutrons into charged-particle reaction products. Commonly used films for such devices utilize the 10 B(n,a) 7 Li reaction or the 6 Li(n,a) 3 H reaction, which are attractive due to the relatively high energies imparted to the reaction products. Unfortunately, thin film or "foil" type thermal neutron detectors suffer from self-absorption effects that ultimately limit neutron detection efficiency. Design considerations that maximize the efficiency and performance of such devices are discussed. Linear arrays fabricated from thin-film-coated pixel detectors are presented with results.

Microfabrication of a gadolinium-derived solid-state sensor for thermal neutrons

“…Gd is also best used as a metal instead of a scintillator compound such as gadolinium oxisulfate (Gd 2 O 2 S), since the metallic form is not as γ-sensitive and the signal from Gd 2 O 2 S is significantly lower relative to Gd metal [ 6 , 7 ]. These data supported the use of natural Gd metal instead of the expensive 157 Gd [ 13 ].…”

“…Solid-state neutron detectors can be mass-produced, are compact for portability and field monitoring, and can operate on a few volts without requiring high power [ 23 ]. Our planar semi-conductor detector is a straightforward configuration for fixed or mobile neutron monitoring due to advantages of size [ 5 ], sensitivity, weight, power consumption, safety, transportability, robustness, technological maturity [ 7 ], and manufacturing cost, and conventional wafer-level device microfabrication is possible for high throughput [ 13 ].…”