Flight Performance of the HEATRigidity

The HEAT (High Energy Antimatter Telescope) instrument was successfully own by high altitude balloon in May 1994. HEAT combines a new magnet spectrometer, comprised of a two-coil superconducting magnet and precision drift tube hodoscope, with a transition radiation detector and electromagnetic shower counter for particle identiication. Flight data are presented which demonstrate that the spectrometer provides a mean maximum detectable rigidity (MDR) of 170 GV for electrons observed during the HEAT ight, suucient to determine the rigidity of cosmic ray electrons and positrons at energies up to 50 GeV.