Influence of Solar Energetic Particles on Photometric Characteristics of the CCD Detector of the LASCO/C3 Space Telescope

The data from the LASCO/C3 space telescope onboard the SOHO space observatory are used to investigate the effect of solar energetic particles on the telescope's CCD detector. A special feature of the instrument is that it is located at the L Lagrange point of the Sun–Earth system at a distance of 1.5 million km from the planet and is not protected from charged particles by the Earth's magnetic field. In the period from 2018 to 2024, a decrease in the instrument's sensitivity was detected at a rate of 0.94 ± 0.03% per year and an increase in the signal dispersion at a rate of 4.9 ± 0.1% per year. The main probable reason is an uneven decrease in the photometric sensitivity of the detector in different pixels. The effect of charged particles produced during large solar flares on the sensitivity of CCD detector was also studied. According to the data obtained, the influence of individual flares on the detector's sensitivity is insignificant and cannot be detected within the measurement error. However, this effect can accumulate, resulting in significant changes in CCD sensitivity over several years or more.