The low background spectrometer TGV II for double beta decay measurements

The low-background multi-HPGe spectrometer TGV II installed in the Modane Underground Laboratory (France) is described in detail and the results of the background measurements are reported. The spectrometer is focused on the double beta decay measurements with two isotopes—106Cd (2νEC/EC2νEC/EC mode) and 48Ca (ββββ mode). A basic summary of the physics of ββββ decay (especially EC/EC mode) is also given.