Geiger Tube Telescope (GTT)

Description

This experiment used seven miniature Geiger tubes in three arrays to measure proton and electron fluxes in interplanetary space and in the vicinity of Jupiter. Detector groupings were as follows: (1) a three-element (A, B, and C) differentially shielded telescope, with tube C shielded omnidirectionally and used for background subtraction to provide directional rates such as A-C (5-21 MeV electrons and 30-77.5 MeV protons) and B-C (0.55-21 MeV electrons and 6.6-77.5 MeV protons), (2) a three-element (D, E, and F) triangular array, each element responding to electrons above 31 MeV and protons above 77.5 MeV, and (3) a thin-window tube (G) with a gold-plated elbow as the aperture which admitted scattered electrons above 0.06 MeV while discriminating strongly against protons. Single element and coincidence rates were telemetered from the first two telescopes. The telemetry bit rate prevailing during the Jupiter encounter permitted directional sampling in intervals of about 14 deg of roll about the spin axis. For further details, see Baker and Van Allen, J. Geophys. Res., v. 81, p. 617, 1976.