Avalanching MRS Detectors for Scintillation Photodetection

51075-98-I Avalanching MRS Detectors for Scintillation Photodetection--Cremat, 45 Union Street, Watertown, MA 02172-2523; (617) 926-0661 Mr. Fred Olschner, Principal Investigator Mr. Fred Olschner, Business Official DOE Grant No. DE-FG02-98ER82561 Amount: $74,967 An inexpensive, fast, highly sensitive, compact, solid state photosensor would find great utility in particle and gamma-ray detectors used in high energy physics experiments (including counters such as anticoincidence shields). Unfortunately, currently available photosensors all have serious shortcomings: (1) the photomultiplier tubes are bulky, fragile, and sensitive to magnetic fields, and (2) the silicon avalanche photodiodes are too expensive to use in large areas. Other solid state photosensors are not sufficiently sensitive for this application. This project will determine whether a new design of silicon photodiode known as the Avalanching MRS (Metal-Resistance-Semiconductor) detector would offer performance comparable to that of beveled-edge avalanche photodiodes while being much more manufacturable. MRS detectors use a very simple manufacturing process, and probably could be mass produced inexpensively, unlike normal avalanche photodiodes which use a handmade production process and cost approximately $1000 per square centimeter. In Phase I, this new photosensor design will be assessed by building and testing a batch of them. Successfully building these detectors using automated ¿planar¿ processes would demonstrate that they could be inexpensively manufactured. Testing their light sensitivity using simulated and real scintillated light would demonstrate their superior performance. Commercial Applications and Other Benefits as described by the awardee: The proposed detectors could be applied to many of the same applications currently addressed by standard avalanche photodiodes. In addition, new applications would become feasible due to the projected reduced cost of MRS detectors compared to avalanche photodiodes. These applications include detectors for high energy and nuclear physics research, medical imaging, bomb detection instrumentation, nuclear power plant instrumentation, and nuclear verification detectors._