PROBA-V Energetic Particle Telescope instrument and its early science results

The Energetic Particle Telescope (EPT) is a science-class instrument designed to measure contamination-free spectra of electrons (0.5 - 10 MeV), protons (9 - 300 MeV) and He-ions (38 - 1200 MeV) within a 52 deg. Field Of View (FOV) angle and a 149 cm(2) sr aperture geometrical factor. The instrument is modular and it can be in-flight configured so as to provide up to 19 energy channels per particle type. The EPT dimensions are 210 mm x 162 mm x 128 mm, the total mass is 4.6 kgs and its power consumption amounts to 5.6 Watts. The satellite PROBA-V was launched on the 7th May 2013 onto a sun-synchronous circular Low Earth Orbit at 820 km altitude and 98.7 deg. inclination. Its local time at descending node is 10:30. The EPT has been accommodated onto the S/C so as to get its boresight oriented Eastwards during local night time and Westwards during local day time. However, the East/West orientation has been modified during the commissioning phase to allow measurements of Pitch Angle Distribution (PAD). The latters were part of a plan aimed at validating the EPT hardware and the data analysis software. The EPT is currently acquiring data that are used for (i) cross-validation of radiation monitors or spectrometers, (ii) cross-validation of space radiation models, (iii) development of steady-state electron and proton flux models and (iv) space weather studies. The EPT validation results along with early results of the ongoing science studies are presented in this paper.