*** 9761316 Karplus This small business innovation research Phase I proposal seeks to develop an avalanche photodiode for use as a high gain single photon imaging device that generates the time and position of incidence for each detected photon event. Such a device will provide a lower cost, higher performance alternative to microchannel plate based single photon imaging detectors and will provide data in a format that is more conducive to rapid analysis than traditional image files. Applications for the device include a variety of emerging techniques for real time in-vivo imaging of physiological and developmental processes such as calcium dynamics and free radical production using luminescent indicators. Phase I of this project involves three iterations of the design, construction and characterization of an imaging avalanche photodiode device to verify the device concept, establish the design requirements and determine the production costs. Phase II will produce a commercial imaging system that consists of an imaging avalanche photodiode in a c-mount enclosure, customized support electronics and data acquisition and analysis software. Phase III will pursue opportunities to use the device for other imaging applications such as positron emission tomography and single photon emission computed tomography, and will also consider how to apply the position sensing technology to similar semiconductor devices. Many scientific and medical imaging applications require high gain, high resolution image sensing devices. The need for improving the performance and reducing the cost of these devices is expected to grow to keep pace with the development of luminescent labels that can be used for in-vivo imaging of calcium dynamics, free radical production, gene specific activity, and other physiologically significant processes. Our device will provide higher performance at a lower cost to both the applied and research communities in science and medicine, making research activities more efficient and reducing the cost of clinical procedures. It will also make new research and commercial applications possible because of a unique image acquisition and analysis paradigm that will be used. ***
