Study of low noise preamplifier systems for use with room temperature mercuric iodide (HgI/sub 2/) 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 of 295 eV (FWHM) for Fe-55 source (5.9 keV) and 225 eV (FWHM) for the pulser have been obtained with both the detector and the input FET at room temperature using the pulsed-light feedback preamplifier. It has been shown that cooling the input FET using a small Peltier element allows the energy resolution to be improved up to 25%

Place of HgI/sub 2/ energy-dispersive x-ray detectors

After a review of solid-state conduction counters, in general, and of the history of mercuric iodide, in particular, the theory of operation of solid-state energy-dispersive HgI/sub 2/ detectors is dicusssed. The main factors which limit energy resolution in solid-state compound detectors are considered, including statistical fluctuations in charge generation, the window effect, trapping, inhomogeneities in the detector material, and electronic noise. Potential applications of room-temperature HgI/sub 2/ x-ray detectors are listed, and general considerations are discussed for x-ray fluorescence analysis with HgI/sub 2/. Directions of current investigations are given. (LEW

Mobility and trapping time in HgI/sub 2/: a comparison of measurement methods and results

The charge transport parameters of a solid-state nuclear radiation detector are of paramount importance in determining the spectrometric performance. The free drift lengths (lambda) for electrons and holes are given in terms of the products of mobility (..mu..) and trapping time (tau) for electrons and holes. For good spectrometric performance the carrier free drift lengths should be much greater than the thickness of the detector. The ..mu.. tau product is so important in this regard that different solid-state detector materials are compared on the basis of their ..mu.. tau values, and for a given material progress is gauged by the current value of ..mu.. tau which it is possible to achieve. Workers in the field are fond of plotting ..mu.. tau versus time (in years, usually) to show how the state-of-the-art is advancing, often towards some asymptotic value. Different methods of measuring the charge transport parameters of mercuric iodide (HGI/sub 2/) are discussed and experimental values are presented. (WHK

Performance of room temperature mercuric iodide (HgI/sub 2/) detectors in the ultra low energy x-ray region

Performance of room temperature mercuric iodide x-ray spectrometers has been recently improved through new fabrication techniques and further development of low noise associated electronic systems. This progress has extended the range of measurements to the ultra low energy x-ray region at room temperature. This paper reports the study of the effect of contact material on the performance of HgI/sub 2/ detectors in the low energy x-ray region