Performance of a segmented Ge/BGO detector as an escape suppressed and pair spectrometer

A γ-spectrometer consisting of one planar and two large volume coaxial germanium crystals, closely packed in a common cryostat, and of a cylindrically symmetric bismuth germanate shield has been built. The system can simultaneously be operated in various escape suppressed modes as well as in a pair spectrometer mode, choosing appropriate coincidence and anticoincidence conditions. This unique feature of the system gives rise to both an exceptional wide dynamical range in γ-ray energies and a good background suppression. The performance of the system has been measured in an energy range between 120 keV and 3.4 MeV using standard radioactive sources. (orig.)