Accelerator Test of an Angle Detecting Inclined Sensor (ADIS) Prototype with Beams of 48Ca and Fragments

The Angle Detecting Inclined Sensor (ADIS) system is a highly innovative and uniquely simple detector configuration used to determine the angle of incidence of heavy ions in space instruments. ADIS replaces complex position sensing detectors (PSDs) with a system of simple, reliable and robust Si detectors inclined at an angle to the instrument axis. The charge and mass resolution of heavy ion instruments in space depends upon determining the ions' angles of incidence. Such instruments should identify ionic species (at least by element, preferably by isotope) from protons through the iron group. The Resource constraints on spacecraft generally mean that instruments that measure cosmic rays and Solar energetic particles must have low mass (a few kg) and power (a few W), be robust and reliable yet highly capable. An ADIS based system is being incorporated into the High Energy Particle Sensor (HEPS), one of the instruments in the Space Environment Sensor Suite (SESS) on the National Polar-orbiting Operational Environmental Satellite System (NPOESS). In August 2004 we tested ADIS prototypes with a 48Ca beam at the National Superconducting Cyclotron Laboratory's (NSCL) Coupled Cyclotron Facility (CCF). We demonstrate through heavy ion calibration with a Ca beam that our prototype charged particle design with an ADIS system has a charge resolution of better than 0.25 e at Ni.