SH038-08
A Radiation Environmental Study for the Metis Coronagraph on board Solar Orbiter

Monday, 14 December 2020: 05:58
Virtual
Catia Grimani, University of Urbino Carlo Bo and INFN Sect. in Florence, Urbino, Italy, Vincenzo Andretta, INAF - Osservatorio Astronomico di Capodimonte, Napoli, Italy, Paolo Chioetto, CNR-Institute for photonics and nanotecnologies, Padua, Italy, Vania Da Deppo, CNR-IFN UOS Padova LUXOR, Padova, Italy, Michele Fabi, University of Urbino Carlo Bo and INFN Florence, Urbino, Italy, Samuel Gissot, Royal Observatory of Belgium, Brussels, Belgium, Giampiero Naletto, University of Padova, Department of Information Engineering, Padova, Italy, Christina Plainaki, ASI-Italian Space Agency, Roma, Italy, M Romoli, University of Florence, Florence, Italy, Daniele Spadaro, INAF - Osservatorio Astrofisico di Catania, Italy, Catania, Italy, Marco Stangalini, Italian Space Agency, Roma, Italy, Daniele Telloni, INAF-OATO, Turin, Italy and Michela Uslenghi, Institute of Space Astrophysics, and Cosmic Physics, INAF, Milan, Italy
Recorded Presentation
Abstract:
The solar cycle 24 was the weakest of the last hundred years. All predictions available in the literature for the solar cycle 25 indicate a similar or even weaker period of solar activity. As a result, the highest galactic cosmic-ray flux of the last century will strike the Solar Orbiter spacecraft along its orbit. Conversely, only one solar energetic particle event (SEP) per year (average predictions) is expected during the cruise phase of the mission in the fluence range 106-107 protons cm-2 above 30 MeV.

An instrument dedicated radiation environmental study will be carried out for Metis, the coronagraph on board Solar Orbiter. Pre-launch Monte Carlo simulations aiming to estimate the overall dose absorbed by the Cerium treated polarimeter lenses indicated an average dose absorption of 2000 Gy for the extended mission, while the lenses showed a few % transmittance loss with a 106 Gy of gamma radiation.

Monte Carlo simulations will be also performed to study energetic particle single hits and tracks in the images of the visible light and ultraviolet detectors. On the other hand, dark images provide precious clues for cosmic-ray monitoring and images background estimates for both Metis and EUI (Extreme-Ultraviolet Imager) detectors. Collaboration with the EPD (Energetic Particle Detector) instrument scientists and data from cosmic-ray experiments in orbit during the Solar Orbiter mission will allow us to study cosmic-ray variations along the spacecraft orbit and their effects on the instrument performance.

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