Design, fabricate, calibrate, test and deliver two satellite electron flux detectors

A satellite borne High Energy Electron Analyzer has been designed to measure electrons in the range of 1 MeV to 10 MeV. Very low background from omnidirectional charged particles is achieved with two Solid State Detectors and a BGO scintillator crystal arranged in a telescope unit and with the requirement of a triple coincidence of electrons in the measurement range. Ten energy bins are provided by the BGO over this range. Additionally, electron singles above 10 MeV and proton singles above 15.7 MeV are measured by the BGO crystal. The Solid State Detectors also provide measurements for proton singles from 4.1 MeV to 269 MeV. The background is further reduced by a plastic scintillator, surrounding the BGO, and placed into anticoincidence with the electron measurement. A complete electron energy spectrum plus singles measurement is generated every .512 seconds. The higher count rates from 3.5 to 1000 kcps are accommodated with compression counters while the lower count rates are accumulated in straight ripple counters. Three different coincidence requirements (Front SSD coincidence, Back SSD coincidence, Shield anticoincidence) are selectable by ground command. Two instruments have been fabricated, tested and calibrated. The first of these has been integrated on the CRRES satellite and is currently undergoing spacecraft testing at BASD.