Cosmic-Ray Telescope
A set of three silicon surface barrier detectors was used in the form of a dE/dx vs range telescope to determine the flux of protons in the energy intervals 15 to 70 MeV and 70 to 170 MeV, alpha particles in the energy ranges 15 to 70 MeV/nucleon and above 70 MeV/nucleon, and protons and alpha particles in the energy interval 1.2 to 15 MeV/nucleon. The detector was mounted on the spacecraft so as to point always in the antisolar direction. A 128-channel pulse-height analyzer was used to sample the energy loss in the top detector element of the telescope. It was possible to pulse-height analyze protons and alpha particles from 15 to 70 MeV/nucleon, protons from 70 to 170 MeV, and alpha particles with energies above 70 MeV/nucleon. Two count rates and two pulse height analyses were obtained every 72 or 18 s according to whether the spacecraft transmission rate was 8-1/3 or 33-1/3 bps. The experiment performed normally from launch until October 1965, when the spacecraft was turned off to conserve power. When the spacecraft was turned on again at a later time, the detector did not respond.