A High Sensitivity Beta Imaging System for Surface Assessment

65584 The monitoring of tritium on various surfaces at DOE facilities presents unique challenges for dosimetry and health-risk assessment. Thus, there is a need for a hand-held, direct-reading instrument. So far, the methods proposed for this purpose have not had the sensitivity (or required long count times) to be of practical use. This project will develop a practical, easy-to-use, multi-element, solid-state, Avalanche Photodiode (APD) array-based instrument for rapid detection and imaging of tritium contamination on surfaces and in air. During Phase I, a multi-element APD unit was designed and constructed. The evaluation of the Phase I unit demonstrated that the APD array-based instrument not only surpasses the performance of current commercial instruments, but also meets regulatory guidelines that no other compact, real-time surface imaging instrument has approached. The low noise of the APD detector provided a way to rapidly detect levels of activity less than 1000 dpm/100 cm2. Phase II will extend the Phase I research into the development of a multichannel field-usable prototype for dosimetry and imaging. Improvements in the electronics and readout, along with a mechanical design that allows data collection in various environmental conditions, will lead to a sophisticated instrument for the rapid detection and imaging of tritium on various surfaces. Commercial Applications and Other Benefits as described by the awardee: The proposed surface monitor should significantly enhance the ability to monitor the presence of tritium at controlled sites. There is a critical need for such instruments at DOE facilities undergoing decommissioning and at facilities, which require screening before equipment can be released. The need also exists in the medical community for improved tritium imaging to diagnose and locate health problems.