Development of the dual-sided microstructured semiconductor neutron detector

Microstructured semiconductor neutron detectors (MSNDs) have long been investigated as a replacement for inefficient thin-film-coated semiconductor neutron detectors. Thin-film-coated semiconductor thermal neutron detection efficiency is restricted to 4-5%. MSNDs improved upon these devices with etched perforations into the diode backfilled with neutron conversion material. Neutron absorption and reaction-product detection efficiency was greatly improved, leading to theoretical intrinsic thermal neutron detection efficiencies greater than 45%. Previous attempts at double-stacking MSNDs to increase the detection efficiency were successful, but were accomplished with great difficulty, where device alignment and proved to be challenging. The development of the dual-sided microstructured semiconductor neutron detector (DSMSND) provides the simplicity of a single device with the detection efficiency of a double-stacked detector. Trenches were etched into the top and bottom of a single vertical pvn-junction Si diode and backfilled with 6LiF neutron conversion material. The first such devices fabricated yielded thermal neutron detection efficiencies between 9.6-16.6%. Theoretical intrinsic thermal neutron detection efficiencies of greater than 79% are possible with a single 1-mm thick silicon diode.