Compton-suppression spectrometer for in-beam coincidence measurements and proposal for a detector configuration consisting of systems with a large solid angle

A γ-γ coincidence apparatus consisting of a Compton-suppression spectrometer with a large solid angle of 54 msr and a single Ge detector is described, and examples of experimental results obtained in in-beam spectroscopy of heavy-ion induced reactions are presented. Furthermore, a γ-γ coincidence Compton-suppression spectrometer consisting of three veto systems for three Ge-detectors is described. By using one integrated Compton-suppression shield consisting of a NaI(Tl) detector optimally divided into four parts for the Ge detectors, an extraordinarily large solid angle of 100 msr is obtained for each Compton-suppression spectrometer. At the same time the total solid angle of the NaI(Tl) veto shield is minimized, which is the central problem when measuring γ cascades of high multiplicity. (author)