GaP Avalanche Photodiodes for Radiation Detection

In this Phase I DHS STTR proposal submitted in response to Topic H-SB06.2-007, Aymont Technology, Inc. and University of Virginia will develop gallium phosphide (GaP) avalanche photodiodes (APD) with high quantum efficiency (QE>50% at 360 nm in Phase I), high gain (>100000), and high speed (2 GHz bandwidth). This Phase I effort will build upon previous work in the Campbell group that demonstrated the efficacy of GaP APDs for blue to near UV wavelengths. The response of these APDs will be tailored to match the LaBr3: Ce3+ response to 662 keV gamma radiation. A detailed commercialization plan will also be developed in Phase I. The Phase II effort will inprove gain to 1000000 and QE to 70% by using more advanced APD design concepts, demonstrate the APD capability in a radiation detection application, and ready this technology for commercialization. Replacement of photomultiplier tubes with GaP APDs for use with LaBr3: Ce3+ scintillators will greatly improve the detection of small amounts of nuclear material in homeland security applications, environmental monitoring, as well as for law enforcement and regulatory agencies.