A new versatile underground gamma-ray spectrometry system

• A new gamma-ray spectrometer was installed in the underground laboratory HADES.
• It is a versatile ultra low-background gamma-ray spectrometer system (Pacman).
• It has a large inner volume and can host large samples as well as several detectors.
• The background characteristics are presented for different HPGe configurations.
• Detection limits for various anthropogenic radionuclides are given.

The newest development in IRMM's underground analytical facility is a large lead shield lined with copper that is versatile and can host several detectors of different types. The characteristics and the background performance of the shield are described for four different detector configurations involving HPGe-detectors and NaI-detectors. The shield has been designed to swap detectors, while still maintaining a low background. This enables testing of detectors for other experiments and optimisation of detection limits for specific radionuclides in different projects.