Design and Characterization of a Low Power Consumption, HPGe Spectrometer

A low power consumption, high resolution germanium spectrometer is described. The spectrometer consists of an HPGe detector (either conventional or reverse electrode), a charge loop amplifier, a high count rate indicator, detector bias shutdown electronics, and a portable cryostat. A brief analysis of the charge loop amplifier is presented. Data for FET noise at reduced drain currents is also presented. The effects of various circuit components on temperature coefficient of gain are described along with measured temperature coefficient. Finally, the resolution and peak shift versus count rate are presented along with the spectrometer configuration.