Preliminary results from the prototype Synchrotron Radiation Detector on Space Shuttle mission STS-108

Abstract A Synchrotron Radiation Detector measures synchrotron radiation emitted by high energetic particles in the earth magnetic field. This allows to identify cosmic ray electrons and positrons with energies in the TeV region. One possibility for such a detector outside the atmosphere uses YAP crystals to measure synchrotron photons with energies in the keV range. As such a detector can not distinguish between photons and electrons, the main problems are the diffuse cosmic ray gamma background and low energetic electrons in the vicinity of the earth. While the intensity of the diffuse gamma rays is known quite well, there exists limited knowledge about keV-electrons in low earth orbits. To measure these electrons a Prototype Synchrotron Radiation Detector (PSRD) was flown with Space Shuttle mission STS-108 (Dec.2001) and preliminary analysis of the data show very favorable results.