Speaker
Description
HEPI is a new instrument developed to measure >300 MeV/nuc particles in a very small (‘< 1U’) package which would be suitable for a CubeSat mission as well as for hosting on larger missions. It uses the principle of Cherenkov radiation which is one of the earliest techniques used in space radiation measurements, for example the cosmic ray detector on the first UK satellite, Ariel-1. Although it has been less frequently adopted in recent years, the technique still has advantages and can offer good discrimination against the fluxes of particles at lower energies.
Measurements of particles at such high energies have been limited to date so HEPI could enable a considerable increase in the amount of data collected. It is designed primarily for measuring solar energetic particles but can also be applied to studies of radiation belts for example where such high energy particles also exist but are poorly mapped. This paper will describe the instrument requirements, design options and trade-offs, some of the simulations carried out, the approach to rejection of unwanted signals and the development of a breadboard version. Testing of HEPI with atmospheric muons and in a proton beam (up to 500 MeV) at TRIUMF in Canada will be described. Further developments will be touched on including proposals for a test flight of elements of the instrument on a CubeSat.
