  Evaluation of single, coincidence and anticoincidence gamma-ray spectrometry
methods has been carried out with the aim to search for double-electron capture
in 74Se. This process is unique, because there is probability for transition to
the 2+ excited state in 74Ge (1204 keV), and de-excitation through two
gamma-quanta cascade with energies of 595.9 keV and 608.4 keV. Long-term
measurements with anticosmic shielded HPGe spectrometer and the coincidence
HPGe-NaI(Tl) spectrometer did not show any evidence for the double-electron
capture in 74Se. The best limit for the half-life of the double electron
capture in 74Se (both for the neutrinoless and two neutrino processes) was
estimated to be >1.5x10E19 years.
