Fabrication and Characterization of High-Purity Germanium Detectors with Amorphous Germanium Contacts

Abstract

Large, high-purity, germanium (HPGe) detectors are needed for neutrinoless double-beta decay and dark matter experiments. Currently, large (> 4 inches in diameter) HPGe crystals can be grown at the University of South Dakota (USD). We verify that the quality of the grown crystals is sufficient for use in large detectors by fabricating and characterizing smaller HPGe detectors made from those crystals. We report the results from eight detectors fabricated over six months using crystals grown at USD. Amorphous germanium (a-Ge) contacts are used for blocking both electrons and holes. Two types of geometry were used to fabricate HPGe detectors. As a result, the fabrication process of small planar detectors at USD is discussed in great detail. The impact of the procedure and geometry on the detector performance was analyzed for eight detectors. We characterized the detectors by measuring the leakage current, capacitance, and energy resolution at 662 keV with a Cs-137 source. Four detectors show good performance, which indicates that crystals grown at USD are suitable for making HPGe detectors.

arXiv comment18 pages and 13 figures

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Cited by in corpus (8)

• Impact of Charge Trapping on the Energy Resolution of Ge Detectors for Rare-Event Physics Searches
• Characterization of High-Purity Germanium (Ge) Crystals for Developing Novel Ge Detectors
• The Impact of the Charge Barrier Height on Germanium (Ge) Detectors with Amorphous-Ge Contacts for Light Dark Matter Searches
• Characterization of High-Purity Germanium Detectors with Amorphous Germanium Contacts in Cryogenic Liquids
• Evidence of cluster dipole states in germanium detectors operating at temperatures below 10 K
• Development of Planar P-type Point Contact Germanium Detectors for Low-Mass Dark Matter Searches
• Development of low-threshold detectors for low-mass dark matter searches with a p-type germanium detector operated at cryogenic temperature
• Fabrication of p+ contact by thermally induced solid state regrowth of Al on p-type Ge crystal