Large area high-efficiency time-of-flight system for detection of low energy heavy evaporation residues at the electrostatic separator VASSILISSA

A large-area thin timing detector for slow heavy nuclei was developed. The apparatus is based on the transport of secondary electrons by crossed electric and magnetic fields with subsequentamplification by micro-channel plate multipliers. To increase the registration efficiency secondary electrons are collected from the both sides of the emitter foil. An intrinsic time resolution of (380±30) ps and registration efficiency of (95±5)% were obtained for the single TOF detector using a 226Ra α-source. A time resolution of (400±30) ps and registration efficiency close to 100% were measured for heavy ions for the single TOF detector. A time-of-flight system consisting of two such detectors is extensively used in the experiments with heavy nuclei at the kinematic separator VASSILISSA [1,2].