INTEGRAL Picture Of the Month
January 2019

INTEGRAL POM
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Artificial intelligence unfolding for INTEGRAL IREM data

Solar Energetic Protons (SEPs) and the Radiation Belts (RBs) are two of the three main sources of particle radiation in the near-Earth space, the third being Galactic Cosmic Rays. Such radiation can be detrimental to satellites and the function of their components either through single event effects (e.g. data corruption) or cumulative effects, which can eventually render satellite systems inoperable. Furthermore, particle radiation is ionizing and able to both damage DNA and cause prompt radiation sickness. It is therefore a very important factor for manned missions to the Moon and Mars as it can have severe effects on astronauts' health.

A large volume of measurements during SEPs and from trapped energetic particles within the RBs are collected from a series of radiation monitors on-board a multitude of satellites. The INTEGRAL Radiation Environment Monitor (IREM) on-board INTEGRAL provides important measurements on SEPs and trapped particles since 2002 (see, e.g., INTEGRAL POM's July 2018, May 2012, December 2003). However, the raw monitor data, i.e. count-rates, must be rendered into useful information in the form of particle fluxes in physical units. This flux data can then be used by satellite operators and radiation environment physicists and engineers. Nevertheless, the derivation of fluxes from count-rates, or "unfolding", is not trivial as it is an ill-posed inverse problem and it can yield grave errors or even completely unphysical results, e.g. negative particle fluxes.

GenCORUM is an Artificial Intelligence method internally employing a Genetic Algorithm. With it, it is possible to unfold the count data into solar proton fluxes and electron fluxes within the outer RB using IREM raw count measurements to a high level of accuracy. The IREM flux data were validated with proton fluxes from the ESA SEPEM Reference Dataset (RDS) and electron flux measurements from the Van Allen Probes (VAP) mission.

Upper left: Image of the SUN from the SOHO mission (http://sci.esa.int/soho/47703-a-change-of-pace-for-eit-soho-s-ground-breaking-camera/).
Upper right: Mean solar proton spectrum from the GenCORUM plotted against the SEPEM RDS mean proton spectrum.
Bottom left: Artist impression of the Earth's Radiation Belts ( https://www.nasa.gov/sites/default/files/radiation_belts_0.jpg).
Bottom right: Mean trapped electron spectrum from the GenCORUM plotted against the VAP data mean electron spectrum.

References:
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