Neutron detector using Gd-based scintillator and wide-bandgap semiconductor photovoltaic

摘要

An enhanced neutron sensing device, that couples a gadolinium based scintillator with at least two wide bandgap photodiodes to achieve a high sensitivity, low power, and portable neutron detector with high gamma discrimination. Once coupled with electrical signal processing and read-out electrons, the device will output the incident neutron flux in the environment and can be used in locations with known sources of neutrons or for identifying clandestine nuclear materials.

主权项

1. A neutron detector, comprising:
a 157-Gd isotopically enriched dopant-activated single-crystal or nano-crystalline Gd-based scintillator coupled with two or more wide bandgap epitaxially grown photodiodes, wherein:
the scintillator has a photo yield exceeding 6000 photons/neutron and an emission lifetime of 50 ns or less;each photodiode has a shunt resistance that is 3-5 orders of magnitude larger than GaAs and 5-7 orders of magnitude larger than Si;each photodiode has a dark current, at zero bias, of 1 nA/cm2 or less;each photodiode has an output voltage greater than 0.75 V under excitation by a 1 nA/cm2 pulse and greater than 0.5 V under excitation by a 0.1 nA/cm2 pulse;each photodiode absorbs greater than 98% of incident light with a wavelength of 650 nm or less in less than 3 microns;each photodiode has a base doping gradient that generates a built in field that drives minority carriers to respective sides of the photodiode; andeach photodiode has a cross section thickness of less than or equal to 3 microns; and signal processing electronics configured to perform pulse-shape, coincidence signal analysis that assesses timing, shape, and amplitude of incident signals generated by the two or more photodiodes to achieve neutron sensing and gamma ray discrimination.