Almost 2500 days in space – the RAMIS radiation detector on the DLR Eu:CROPIS mission

Kurzfassung

RAMIS (size: 140x140x35mm³, mass: 608 gram, power consumption 1.8 Watt) is a radiation detector developed for the DLR Eu:CROPIS satellite mission. RAMIS uses an arrangement of two silicon detectors in telescope geometry and maps the radiation environment in the course of the mission. For this RAMIS stores count- and dose rate data with a 1-minute and energy deposition spectra with a 5-minute cadence. Eu:CROPIS was launched on December 03rd 2018 into a polar orbit circling around Earth at an average altitude of ~600 km. RAMIS is located on the outside of the satellite and was activated on December 05th 2018 and has continuously provided data during the course of the mission. Due to the polar orbit of the satellite RAMIS measures a) the variation of galactic cosmic radiation (GCR) in dependence on the orbit, b) the contributions of protons in the inner Earth radiation (Van Allen), c) variations of the trapped electron intensity during crossings of the outer radiation belt and finally (d) the changes in the radiation environment due to the changes in the solar cycle as seen in a high number of detected Solar Particle Events (SPE). Due to the high complexity of the radiation environment and the various particle contributions a separation of GCR, SAA, Electrons and SPEs becomes a challenge. We tackled this problem by using for the first time a machine learning approach classifying data points based on a random forest algorithm. For this a trainings data set was defined and used as input for the radiation environment classification. This enabled the correct attribution/mapping of the various particle populations. First results applying this machine learning tool will be presented focusing on SPEs as measured with RAMIS in the course of the mission with a focus on the year 2024.