The Majorana Demonstrator Radioassay Program

TL;DR

This paper describes the radioassay program for the MAJORANA DEMONSTRATOR, aiming to ensure ultra-low background levels in Ge detectors for neutrinoless double beta decay search.

Contribution

It reports the measurements of radioactive contamination in materials used for the detector, demonstrating the material purity necessary for the experiment.

Findings

Radioactive isotope contamination levels measured in detector materials

Materials meet purity requirements for low-background experiments

Data supports feasibility of large-scale Ge detector for neutrinoless double beta decay

Abstract

The MAJORANA collaboration is constructing the MAJORANA DEMONSTATOR at the Sanford Underground Research Facility at the Homestake gold mine, in Lead, SD. The apparatus will use Ge detectors, enriched in isotope \nuc{76}{Ge}, to demonstrate the feasibility of a large-scale Ge detector experiment to search for neutrinoless double beta decay. The long half-life of this postulated process requires that the apparatus be extremely low in radioactive isotopes whose decays may produce backgrounds to the search. The radioassay program conducted by the collaboration to ensure that the materials comprising the apparatus are sufficiently pure is described. The resulting measurements of the radioactive-isotope contamination for a number of materials studied for use in the detector are reported.