Investigations of 2β decay measured by low background HPGe spectrometer OBELIX

Abstract

A low background high sensitive HPGe spectrometer OBELIX was installed at the Modane Underground Laboratory (LSM, France, 4800 m w.e.). The detector was designed to measure a contamination of enriched isotopes and radio-impurities in construction materials, to investigate rare nuclear processes such as resonance neutrinoless double electron capture and two-neutrino double beta decay to excited states of daughter nuclei. Spectrometer sensitivity, contamination of NEMO-3 sources and results of 2ν2β− decay of 100Mo to the 0+ (1130 keV) and 2+ (540 keV) excited states as well as future plans for OBELIX detector are given.