9361738 Entine A high speed, high sensitivity avalanche photodiode (ADP) array is proposed to meet the stringent requirements of detectors for high energy physics experiments such as the central tracker vertex detector and calorimeters which are being designed for existing and proposed particle physics detectors. These detectors will have unprecedented performance characteristics to be used as readouts for the very low light levels produced in scintillating plastic fibers which result from charged particle interactions at very high recycle rates. The approach taken will be to modify existing APD designs to yield a device with lower dark current, increased sensitivity at short wavelengths, and faster cycle times when operated in the single photon Geiger mode. Consideration was given to adaptability of the APD to active quenching circuitry. Constructing high gain devices that fulfill detector needs for proportional mode operation such as those required for high dynamic range calorimetry measurements will also be investigated. The data gathered during this work will be used to produce an APD array with the required combination of characteristics to be used in high speed, low light level applications envisioned at modern detectors such as the D0 at Fermilab and L3 at CERN. Millions of detectors will be needed for modern particle physics facilities. This alone is a large market. Also, these improved APD's will find numerous other uses in industrial applications, such as medical imaging, and research applications. *** v s t $ $ $ ( F / / 1 Courier Symbol & Arial 5 Courier New " h fB %fB % C R:\WW20USER\ABSTRACT.DOT Denise Henry Denise Henry