A Study of Low-Noise Preamplifier Systems for Use with Room Temperature Mercuric Iodide (Hgi2) X-Ray Detectors

An analysis of different preamplification systems for use with room temperature mercuric iodide x-ray detectors has been performed. Resistor-, drain-, and light-feedback preamplifiers have been studied. Energy resolution values of 295 eV (FWHM) for an Fe-55 source (5.9 keV) and 225 eV (FWHM) for a pulser have been obtained with both the detector and the input FET at room temperature using a pulsed-light feedback preamplifier. Improvement in energy resolution by cooling the input FET using a small Peltier element has been discussed.