Large Area Zero Bias Solid-state Neutron Detectors

Solid-state neutron detectors utilize latest advancement in semiconductors for development of efficient and economical neutron detectors. The recent shortage and price increase of He-3 resulted in more incentive to reach maturity of this technology and enable replacement of gas based neutron detectors. Solid state neutron detectors provide important advantages over current neutron detectors such as operation at low or zero bias, more compact geometry and possibly lower cost. Producing a thermal neutron detector that can replace a He-3 based detector requires high thermal neutron detection efficiency and very low gamma sensitivity that are not easily achieved with solid-state detectors. Solid-state neutron detectors typically use a converter material with high neutron interaction cross section in which the neutrons interact and produce charge particles (for example 10B(n,α) or 6Li(n,α)). Following a neutron interaction with the converter material these energetic charge particles lose energy as they interact with the surrounding material. If they leave the converter and move into the semiconductor they interact by producing electron-hole pairs that can be collected to produce a measurable current. In some detectors the converter and semiconductor are two different materials, in other cases the semiconductor material itself can have high neutron interaction cross section for example BN [1] or B5C [2]. Solid-state thermal neutron detectors with high boron content were reported with efficiencies of up to 48% [3], however they are limited in size and scaling to large area requires pixelation which makes the detector electronics costly. Detectors developed at Rensselaer Polytechnic Institute (RPI) use unique continuous junction [4] [5] [6] to achieve very low leakage current which enables operation with low electronic noise and simple scaling to large detection area using a single amplification channel.