Calibration of the GOES-13/15 high energy proton detectors based on the PAMELA solar energetic particle observations

The EPEAD and HEPAD instruments on the GOES spacecraft have served over many years as monitors of the solar particles intensities, surveying the Sun and measuring in situ its effect on the near-Earth solar-terrestrial environment. However, the reconstruction of the differential energy spectra is affected by large uncertainties related to the poor energy resolution, the small geometrical factor and the high contamination by out-of-acceptance particles. In this work, the high quality data set from the PAMELA space mission is used to calibrate the high energy (>80 MeV) proton channels of the EPEAD and the HEPAD sensors onboard the GOES-13 and -15, bringing the measured spectral intensities in-line with those registered by PAMELA. Suggested corrections significantly reduce the uncertainties on the response of GOES detectors, thus improving the reliability of the spectroscopic observations of solar energetic particle events.