This Small Business Innovation Research Phase I project will develop a novel thermal neutron detector from boron phosphide (10BP) that will combine the high boron density of a solid with the efficient creation of large response to the neutron interactions. The new detectors will be rugged, compact, highly sensitive to thermal neutrons, relatively insensitive to gamma radiation, fast, and capable of low bias operation. Phase I will develop the innovative technique of MOCVD growth of high quality BP films on graded composition Gap substrates. Films will be grown to thicknesses of several tens of microns and examined for physical structure. After fabrication into detectors, the basic electrical properties will be tested at Spire and then the detectors will be sent to Sandia National Laboratory for radiation testing. Phase II will extend the technology for optimized detector performance and thicker film deposition for greater sensitivity. The overall goal is to achieve a highly neutron sensitive semiconductor detector that is compact, versatile, and potentially capable of imaging applications. The proposed research effort will result in high efficiency, boron phosphide thin film thermal neutron detectors. Their compact size and low voltage operation will make them aptly suited to replace cur-rent gas or scintillator detectors that need to operate portably or under constrained conditions. The novel design of these detectors will also find extended uses in neutron radiography and dosimetry, environmental monitoring, nuclear nonproliferation, and monitoring reactor operations.
