*** 96-60438 Shah This Small Business Innovation Research (SBIR) Phase I Project will explore the use of semiconductor photodetectors to replace photomultiplier tubes in nuclear bore hole logging instrumentation. Advantages are expected in more compact design, low power requirements, increased ruggedness, and insensitivity to magnetic fields. Lead iodide is a promising detector material because its wide bandgap allows low noise operation at room temperature as well as at elevated temperatures. These detectors have very good optical quantum efficiency and low power requirements. Thus, lead iodide photodetectors coupled to scintillators are thought to be promising gamma-ray spectrometers for well logging. Phase I will demonstrate the feasibility of this concept by performing in-depth characterization of these photodetectors. Commercial applications are expected in detectors for bore hole instrumentation and in various process control systems and nondestructive testing of materials. Other potential uses may be found in health care treatments and in scientific research. ***
