The High Energy Telescope provides high resolution chemical and isotopic composition measurements cosmic ray nuclei from hydrogen through nickel using dE/dx vs. residual E analysis with trajectory determination by a hodoscope composed of multi-strip silicon position sensing detectors. Active elements in the the telescope consist of 6 nominal 1000 micron thick position sensing detectors (D1-D6) forming the hodoscope, 6 nominal 0.5 cm thick silicon detectors (K1-K6) for accurate dE/dX and residual energy measurements, a silicon penetration detector (A) to identify particles which penetrate the detector stack, and a plastic scintillator anti-coincidence shield (S) to reduce background by excluding particles outside the acceptance cone of the telescope and particles within the acceptance cone which interact in the telescope to produce secondaries at large angles to the original trajectory.
Energy deposits in each detector D1-D6 and K1-K6 are measured by dual range 4096 channel pulse-height analysis. Using the PHA information and applying corrections for the angle of incidence as determined by the trajectory system, a mass resolution of 0.30 AMU has been achieved for Fe nuclei measured in space. The energy range over which the high resolution measurements are made is approximately 150-400 MeV/n for iron nuclei.
In addition, counting rates for various energy ranges of protons,
electrons, and heavy nuclei are accumulated for energies extending from
about 5 MeV (for protons) through relativistic energies are measured
with a time resolution as fine as 16 seconds.
A full description of the HET and other COSPIN sensors has been
published by Simpson et al. (Astron. and Astrophys., vol. 92, pp. 365
-400, 1992.)
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