Present status of microstructured semiconductor neutron detectors

Semiconductor diode detectors coated with neutron reactive materials have been investigated as neutron detectors for many decades, and are fashioned mostly as planar diodes coated with boron-10 (10B), lithium-6 fluoride (6LiF) or gadolinium (Gd). Although effective, these detectors are limited in efficiency (the case for boron and LiF coatings) or in the ability to distinguish background radiations from neutron-induced interactions (the case for Gd coatings). Over the past decade, a renewed effort has been made to improve diode designs to achieve up to a 10-fold increase in neutron detection efficiency over the simple planar diode designs. These new semiconductor neutron detectors are fashioned with a matrix of microstructured patterns etched deeply into the substrate and, subsequently, backfilled with neutron reactive materials. Intrinsic thermal-neutron detection efficiencies exceeding 40% have been achieved with devices no thicker than 1 mm while operating on less than 5 V.

► Progress on microstructured semiconductor neutron detectors is reviewed. ► Monte-Carlo models with efficiency and simulated spectra are described. ► Methods to manufacture the detectors are described. ► Results from neutron measurements are presented including spectra and efficiency. ► Thermal neutron detection efficiency exceeding 42% was measured.