An ultra-high-throughput, high-resolution gamma-ray spectroscopy system

A high-throughput gamma-ray spectroscopy system is described. It consists of the following: a high-purity Ge (HPGe) detector; a transistor-reset preamplifier (TRP); a gated integrator, shaping amplifier; an analog-to-digital converter (ADC); and digital control and storage circuits. The gated integrator uses a quasi-rectangular prefilter. With the detector used, this prefilter provided ~16% less noise than a gated integrator using a conventional Gaussian prefilter. The ADC has 14-b accuracy, differential nonlinearity <1%, and an analog first-in-first-out memory was used to minimize the effective conversion time of the ADC. For a 333000 counts/s input rate, the effective conversion time of the ADC was <1.8 μs, and the total ADC deadtime per conversion was <2.1 μs for a 1.5-μs gated integrator integration time. This system is capable of depositing ~86000 pile-up-inspected counts/s into memory with a full-width-at-half-maximum resolution of 3.2 keV at the 1.33-MeV energy line