DESIGN AND CONSTRUCTION OF A SILICON SCHOTTKY DIODE DETECTOR FOR SINGLE PROTON COUNTING AT THE MCMASTER MICROBEAM LABORATORY

Abstract

Microbeams have been used for radiation biology research since their introduction in the 1950s. A goal since their inception has been to irradiate individual cells and sub-cellular components with individual charged particles. These two criteria have been simultaneously achievable only within the last decade thanks to new technologies capable of producing very thin materials. The McMaster Microbeam Laboratory wishes to conduct such experiments using a proton beam. However, there are presently no commercially available detectors for this application, which necessitates the need for a new detector. Following literature research, a 10 μm thin Schottky diode detector was selected as the most appropriate type of detector for the setup at McMaster. The design of the detector and detection system geometries were optimized to reduce beam scattering and broadening with the aid of TRIM and MCNP simulations. Two detectors were fully constructed. However, a stable response to radiation was not achieved. One of the detectors appeared to function as a radiation detector very briefly but this result was not reproducible. The I-V curve of the detectors proved that they functioned as expected as diodes. However, without a radiation response no further characterization could be completed. Although problem solving efforts to overcome this issue were unsuccessful, a large silicon dopant concentration is suspected to be a possible cause.