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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 60Co gamma ray. [ABSTRACT FROM AUTHOR]

This paper presents progress on the development of a cryostat intended to improve upon the low-energy threshold (below 0.5 keV) of p-type point contact germanium gamma-ray spectrometers. Ultra-low energy thresholds are important in the detection of low-energy nuclear recoils, an event class relevant to both dark matter direct detection and measurement of coherent neutrino-nucleus scattering. The cryostat design, including a thermal and electrical-field model, is given. A prototype cryostat has been assembled and data acquired to evaluate its vacuum and thermal performance. [ABSTRACT FROM PUBLISHER]

High-purity copper has emerged as a preferred construction material for ultra-low-background HPGe spectrometers and offers excellent bulk radiopurity along with good electrical, thermal, and vacuum properties. Recently, these materials and techniques have been applied to the construction of low-background internal-source gas proportional counters. This work describes the design, construction, and testing of an ultra-low-background internal-source gas proportional counter built primarily of high purity electroformed copper. Energy resolution of ~10% FWHM at 59.5 keV has been achieved, a low-energy threshold of ~3 keV has been reached, and gas gain stability over a 4-week period has been demonstrated. Progress toward low-background operation is described. [ABSTRACT FROM AUTHOR]