A Low-noise Germanium Ionization Spectrometer for Low-background Science

TL;DR

This paper presents a low-noise germanium ionization spectrometer with high sensitivity, suitable for low-background dark matter detection, demonstrating excellent noise performance and thermal stability.

Contribution

It introduces a 1.2 kg high purity germanium detector integrated with a low-background cryostat, achieving record low noise levels for dark matter search applications.

Findings

Achieved 98 eV FWHM noise performance for electronic pulses

Achieved 1.9 keV FWHM noise for 1332 keV gamma rays

Demonstrated thermal stability and suitability for low-background experiments

Abstract

Recent progress on the development of very low noise high purity germanium ionization spectrometers has produced an instrument of 1.2 kg mass and excellent noise performance. The detector was installed in a low-background cryostat intended for use in a direct detection search for low mass, WIMP dark matter. This Transaction reports the thermal characterization of the cryostat, specifications of the newly prepared 1.2 kg p-type point contact germanium detector, and the spectroscopic performance of the integrated system. The integrated detector and low background cryostat achieved full-width-at-half-maximum noise performance of 98 eV for an electronic pulse generator peak and 1.9 keV for the 1332 keV Co-60 gamma ray.