Unfolding the High Energy Electron Flux from CRRES Fluxmeter Measurements

The Combined Release and Radiation Effects Satellite (CRRES) was launched on 25 July 1990 to collect measurements in the earth's radiation belts. One instrument, the High Energy Electron Fluxmeter (HEEF), measured the flux of electrons in 10 channels with energies between 1 MeV and 10 MeV. The channel sensitivities, Ri(E), have been calibrated and partially re-calibrated. We explore the errors introduced in unfolding the electron flux spectrum from the channel measurements and the propagation and growth of calibration and measurement errors. Using numerical experimentation, we fold the responses with known spectra to obtain simulated measurements, add random measurement and calibration errors, and unfold the spectra as 10-bin histograms which are compared with histograms of the original spectra. We observe that the shape (of the response functions) is the major factor in the growth of error in unfolding and in determining which type of error dominates the unfolding process. We conclude that successful unfolding of the electron flux is critically dependent upon the shape of the response functions. The re-calibration of the REEF must be accurately completed if reliable unfolds of the high energy electron flux are to be obtained.Air Force Inst of Tech Wright-Patterson AFB OH School of Engineering is the author of 'Unfolding the High Energy Electron Flux from CRRES Fluxmeter Measurements', published 1996 under ISBN 9781423574262 and ISBN 1423574265.