Two decades of space radiation environment observations with IREM monitor on INTEGRAL

The INTEGRAL Radiation Environment Monitor (IREM) conducts permanent observations of energetic protons and electrons along the orbit of the ESA INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL). IREM was powered on shortly after its launch on 17 October 2002 and since then it operates continuously for more than two decades. The instrument was developed in partnership between ESA, PSI and Contraves Space AG (Now Thales Alenia Switzerland) and belongs to the family of Standard Radiation Environment Monitors (SREMs). Ten identical SREMs were manufactured and are characterized by low weight, small dimensions and low power consumption. They were optimized for detection of particles with energies and fluxes typical to the Earth radiation environment. IREM onboard of INTEGRAL supports large science instruments by permanent measurements of charge particle background along the orbit. Its telemetry is instantaneously used by the spacecraft data handler enabling generation of alerts broadcasted to the rest of the payload. In parallel, IREM permanently measures the Earth radiation environment for the space weather program. These science data include regular radiation belt scans, large number of Solar Energetic Particles detections as well as numerous Forbush decreases. Observations spanned over three solar maxima provide long records on radiation belt dynamics and Cosmic Rays modulation including its spectral variations at low energies. (IREM could also detect rare, explosive events e.g., from the Soft Gamma Repeaters - magnetars.) Extensive database populated with 23 years of observations is open and available for space research community. It was recently upgraded with a new quick-look inspection utility and Python based data analysis tools.