Investigation of rare processes with high purity germanium detectors

The exceptional sensitivity and high resolution of high purity germanium detectors in gamma-ray spectrometry and their use in underground laboratories has increasing application because of the important science and technology that they allow to be studied. In fundamental physics their application is focussed on rare phenomena, e.g. double beta decay, rare nuclear decays and Dark Matter search. In the past years there has been a growing number of underground measurements also in other fields such as environmental monitoring, surveillance of nuclear activities, benchmarking of other physical techniques, Life Science and material selection for equipment which require materials with extremely low levels of radioactivity. This report describes the state of the art in underground gamma-ray spectrometry with high purity germanium detectors. Various applications in underground laboratories are presented.