Validation of techniques to mitigate copper surface contamination in CUORE

TL;DR

This paper evaluates three techniques to reduce copper surface contamination in CUORE, achieving contamination levels that could significantly lower background counts and improve the experiment's sensitivity.

Contribution

The study introduces and compares three mitigation techniques for copper surface contamination, demonstrating their effectiveness in reducing background levels in CUORE.

Findings

Contamination levels below 10E-07 - 10E-08 Bq/cm2 for 238U and 232Th achieved.

Projected background counts in CUORE are reduced to 0.02-0.03 counts/keV/kg/y.

Effective mitigation techniques can significantly enhance CUORE's sensitivity.

Abstract

In this article we describe the background challenges for the CUORE experiment posed by surface contamination of inert detector materials such as copper, and present three techniques explored to mitigate these backgrounds. Using data from a dedicated test apparatus constructed to validate and compare these techniques we demonstrate that copper surface contamination levels better than 10E-07 - 10E-08 Bq/cm2 are achieved for 238U and 232Th. If these levels are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit on the number of background counts in the region of interest is 0.02-0.03 counts/keV/kg/y depending on the adopted mitigation technique.