Automation of a Liquid Nitrogen Cooling System for a High Purity Germanium Detector and Radioanalysis of Sharpie Ink — 90p — Zachariah Thomas¹, Archer Sagaskie², Haylee Busch³, Brianna Mount⁴

^1. University of Michigan-Dearborn, ^3. Kansas Wesleyan University, ^2. Grand Valley State University , ^4. Black Hills State University

The world’s most sensitive experiment to determine the nature of dark matter is the LUX-ZEPLIN (LZ) experiment. Operating out of the Sanford Underground Research Facility (SURF), LZ attempts to find an interaction between the proposed Weakly Interacting Massive Particles (WIMPs) and ordinary matter. A low radiative background is desired in order to detect these rare interactions, and for this purpose the Black Hills Underground Campus (BHUC) operates a low background counting facility at SURF.

This facility uses several High-Purity Germanium (HPGe) detectors to perform gamma-ray spectroscopy to count the gamma rays from samples placed in the detectors and thereby determine the radionuclide content of the samples. The BHUC was one of several low background counting facilities which counted the materials used to build LZ, and it will perform the same function for its successor, XLZD. One of the HPGe detectors used by the BHUC is the now-aboveground SOLO detector which will be used to prescreen samples for their emission rates, to separate out higher-radiation samples that do not have to be counted underground. HPGe crystals are kept at liquid nitrogen temperatures to minimize electronic noise, improving their detector resolution. 

This poster will describe an automated liquid nitrogen cooling system for the SOLO detector using a LabVIEW code which can also email daily updates for its current fill status. 

Additionally, many of the samples analyzed at the BHUC have sharpie ink writing on them,  which adds a source of radiation, which would increase the sample’s perceived activity. Results will be presented on the U,Th,K content of Sharpie ink. 

Black Hills State University
Dr. Brianna Mount