Comparison of background in underground HPGe-detectors in different lead shield configurations

• The variation with time of background in underground HPGe-detectors was studied. It is shown that this variation must be studied carefully in low-level applications for applying a correct background correction.
• The location of background sources was studied by measuring each HPGe-detector in several different lead shields.
• The background sources contributing to all background was calculated and estimated.

In underground HPGe-detector systems where the cosmic ray induced background is low, it is often difficult to assess the location of background sources. In this study, background counting rates of different HPGe-detectors in different lead shields are reported with the aim of better understanding background sources. To further enhance the understanding of the variations of environmental parameters, the background as a function of time over a long period was also studied.