THE HIGH-ENERGY ANTIMATTER TELESCOPE (HEAT) - AN INSTRUMENT FOR THE STUDY OF COSMIC-RAY POSITRONS

The HEAT (High-Energy Antimatter Telescope) instrument has been develo ped for a series of observations in cosmic-ray astrophysics that requi re the use of a superconducting magnet spectrometer. This paper descri bes the first configuration of HEAT which is optimized for the detecti on of cosmic-ray electrons and positrons below 100 GeV. In addition to the spectrometer, a combination of time-of-flight scintillators, a tr ansition radiation detector, and an electromagnetic shower counter, pr ovides particle identification, energy measurement, and powerful discr imination against the large background of protons, The instrument was successfully Bonn aboard high-altitude balloons in 1994 and 1995. The design and construction of the spectrometer and of the detector system s are described, and the performance of the instrument is demonstrated with data obtained in Eight.