First Results of an ADIS Type Charged Particle Detector, Taken at the NSCL Accelerator Facility

We report here the first results from a working ADIS-type charged particle detector for use in space missions. The ADIS system consists of three detectors, two of which are inclined at an angle to the telescope axis, forming the first detectors in a multi-element charged particle instrument. By comparing signals from the ADIS detectors, the angle of incidence of incoming particles can be determined. The ADIS system can thus replace hodoscopes using conventional position sensing detectors (PSD's). PSD's add significant complexity and require additional electronics, increasing instrument mass, power usage and, in many cases telemetry requirements. The ADIS system's angle determination requires only the processing of simple equations, easily within the capabilities of even the slowest on-board processors. Thus a light-weight, low-power ADIS based charged particle telescope is a good candidate for studying high energy charged particles in deep space. We have built a prototype ADIS telescope for laboratory testing. While the detector housing is made specifically for this system, this test model used off-the-shelf components. The prototype model was taken to the National Superconducting Cyclotron Laboratory at Michigan State University. There the instrument was subjected to a primary beam of 48Ca, and fragment beams from that primary. Various detector systems are compared to show how the instrument response varies with respect to detector thickness and orientation. The preliminary results show that the ADIS instrument can distinguish element in the sub-Ca region with charge resolution of ~0.25e.