SEP protons in GEO with the ESA multifunctional spectrometer

Abstract

The AEEF-TDP8 (ESA Alphasat Environment and Effects Facility - Technology Demonstration Payload 8) integrates the radiation monitor Multi-Functional Spectrometer (MFS) and the CTTB (Component Technology Test Bed). The two units are installed on the X panel of the Alphasat satellite as a hosted payload. MFS is an instrument specifically designed to characterise the Space Radiation environment while CTTB was built to monitor the effect of radiation on electrical components (GaN transistors, Memories and Optical Transceivers) in geostationary orbit. The mission lifetime of AEEF/TDP8 is 3 years with possible extension to 5 years and TDP8 is expected to be acquiring scientific data during the whole period. On ground, correlation between radiation environment and radiation effects can be established. Before launch, MFS was submitted to proton and electron beam tests at Paul Scherrer Institute in Switzerland in 2010. The main purpose was the validation and calibration of the MFS proto-flight model together with the estimation of particle energy resolution and identification capability. A full Geant4 simulation with the MFS in-flight configuration was built and used to validate the results from ground tests. The full detector simulation has proved to be a valuable tool for the unfolding of MFS channel counts into particle spectra based on a Single Value Decomposition (SVD) method. Results for Proton spectra measured with the MFS in GEO will be presented, in particular for the case of Solar Energetic Particle (SEP) events registered in 2014 during periods of maximum solar activity of solar cycle 24.