A MODULAR SOLID-STATE DETECTOR FOR MEASURING HIGH-ENERGY HEAVY-ION FRAGMENTATION NEAR THE BEAM AXIS

A multi-element solid state detector has been designed to measure flue nces of fragments produced near the beam axis by high energy heavy ion beams in thick targets. The detector is compact and modular, so as to be readily reconfigured according to the range of fragment charges an d energies to be measured. Preamplifier gain settings and detector cal ibrations are adjustable remotely under computer control. We describe the central detector, its associated detectors and electronics, trigge ring scheme, data acquisition and particle identification techniques, illustrated by data taken with 600 MeV/u Fe-56 beams and thick polyeth ylene targets at the LBL Bevalac. The applications of this work to spa ce radiation protection are discussed.