Testing of a DSSSD detector for the stopped RISING project

An active stopper for the RISING project at GSI has been developed for ββ-decay studies and conversion electron spectroscopy following projectile fragmentation/fission reactions. This system employs six double-sided silicon strip detectors in the final focal plane of the GSI FRagment Separator (FRS) to detect both the fragment implantations and their subsequent charged-particle (α,βα,β, p) decays. The wide range of energy response required (150 keV up to several GeVs) was covered by the use of a logarithmic preamplifier. Measurements with a 207Bi conversion electron source yielded an energy resolution of 20 keV at electron energies of ∼1MeV and a detection threshold of 150 keV. The response to the implantation of 400 AMeV 136Xe ions in the active stopper is also discussed in the present paper.