Present status of experiments TGV I and TGV II is given. The TGV I collaboration has studied the double-beta decay of 48Ca with a low-background and high sensitivity Ge multi-detector spectrometer TGV (Telescope Germanium Vertical). The preliminary results of \({\text{T}}_{{\text{1/2}}}^{{\text{2}}\nu \beta \beta } = (4.2_{ - 1.3}^{ + 3.3} ) \times 10^{19} \) years and \({\text{T}}_{{\text{1/2}}}^{0\nu \beta \beta } >1.5 \times 10^{21} \) years (90% CL) for double-beta decay of 48 Ca has been found after the processing of experimental data obtained after 8700 hours of measuring time using approximately 1 gramme of 48Ca. The aim of the experiment TGV II is the development of the experimental methods, construction of spectrometers and measurement of the ββ decay (β+β+, β+/EC, EC/EC) of 106Cd particularly the 2νEC/EC mode. The theoretical description and performance of the TGV II spectrometer are also given.