A Monte Carlo Simulation of the NOAA POES MEPED Proton Detector

Experience with the NOAA POES satellites has shown that the SEM-2 MEPED proton channels respond to relativistic electron fluxes. The Geant4 code is employed to construct a Monte Carlo simulation of the detector, and computational results are used to derive a characteristic response. At electron energies greater than several hundred keV, all proton channels except the P4 and P5 channels are shown to respond to electrons. Moreover, because significant P6 channel counts are restricted to the domain of energetic electrons (>700 keV) and protons (>6,900 keV), an elevated P6 response may be employed in anti- coincidence with the P4 and P5 channel to identify relativistic electron precipitation. Finally, characterization of the incident electron spectrum may be attempted by examination of proton and electron channel ratios, and the resultant estimate used to correct reported fluxes or extend instrument capabilities.