Temperature Dependent I–V and Resistance Characterization of SuperCDMS Germanium Crystals

We have built a versatile, compact 3He test facility to evaluate high-purity Ge (HPGe) SuperCDMS (Cryogenic Dark Matter Search) detectors. We are able to rapidly identify photolithographic or other defects in the thousands of W-Al transition edge sensors (TESs) on each detector and to evaluate the performance of the underlying substrate. We describe our simple method to measure current-voltage (I–V) characteristics and R vs. T behavior of HPGe detector crystals with resistances up to 100 GΩ. This provides a way to quickly perform diagnostic physics studies. Results provide critical data that give early warning that a crystal may not be suitable for the SuperCDMS underground experiment. Data from tests made on several kg-scale detectors are presented