Linear Avalanche Photodiode Detector Arrays for Gated Spectroscopy with Single-Photon Sensitivity--Radiation Monitoring Devices, Inc., 44 Hunt Street, Watertown, MA 02472-4699; 617-926-1167

Mr. Arieh Karger, Principal Investigator, akarger@rmdinc.com

Dr. Gerald Entine, Business Official, akarger@rmdinc.com

DOE Grant No. DE-FG02-00ER83086

Amount: $750,000

Current high performance, time-resolved spectroscopy systems, used for detecting the proliferation of weapons of mass destruction, usually rely on image intensified charge coupled detector arrays (ICCDs). While ICCDs are capable of single photon sensitivity with nanosecond time resolution via detector gating, performance is limited by the photocathode quantum efficiencies of <15% in the UV and <20% visible to near IR. This project will develop a solid state version of gated ICCDs; namely, high performance Avalanche Photodiode (APD) arrays will be used to develop a linear APD array module with single photon sensitivity, high quantum efficiency (30-80% for wavelengths between 300-700 nm), and gated modes of operation. Phase I experimentally demonstrated the key components of the linear APD array module: high efficiency single photon detection at liquid nitrogen temperatures was demonstrated, several linear APD arrays that exhibited excellent gain and noise characteristics were fabricated, and an innovative solution for the gated integrator preamplifier was developed. In Phase II, the linear APD fabrication techniques will be further refined to produce an optimal 1 x 64 element array, optimized for low noise and single photon detection efficiency. Likewise, the preamplifier electronics and readout will be optimized, and a 64-channel data acquisition system will be completed. The data acquisition system, linear APD array, and a liquid nitrogen dewar will be integrated in a prototype module. This module will be coupled to a spectrometer, fully characterized, and compared to gated ICCDs.

Commercial Applications and Other Benefits as described by the awardee: The linear APD detector array module should significantly increase the sensitivity of time-resolved optical spectroscopy applications. These applications include remote sensing LIDAR (Light Detection and Ranging), fluorescence decay spectroscopy, and biological and chemical detection.