A High-Rate Spectroscopy System for Use with Ge(Li) Coaxial Detectors

A high-rate gamma-ray spectroscopy system with a 40 cc Ge(Li) coaxial detector is described which utilizes a direct-coupled recycling preamplifier, a unipolar Gaussian filter amplifier with only one differentiating network, and a pileup rejector and baseline inspection circuit, to yield excellent resolution. A family of resolution curves is shown as a function of the input count rate (from 50K cps to 175K cps) and of the actual data acceptance rate. For an input rate of 100K cps and an acceptance rate of 5.5K cps the FWHM and FWl/10M for the 1.33-MeV peak of 60Co was 2.2 keV and 4.24 keV, respectively. The system lends itself to high counting rates by eliminating the need for pole-zero compensation and baseline restoration.