High-energy solar X-ray spectroscopy with the IMPRESS CubeSat

Amir Caspi ¹ Lindsay Glesener ² Demoz Gebre-Egziabher ³ David Smith ⁴ John Sample ⁵ Trevor Knuth ² Athanasios Pantazides ³ Kail Laughlin ³

¹Planetary Science Directorate, Southwest Research Institute, Boulder, CO, USA
²School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
³Department of Aerospace Engineering & Mechanics, University of Minnesota, Minneapolis, MN, USA
⁴Physics Department, University of California, Santa Cruz, Santa Cruz, CA, USA
⁵Department of Physics, Montana State University, Bozeman, MT, USA

The IMpulsive Phase Rapid Energetic Solar Spectrometer (IMPRESS) experiment is a CubeSat-based, Sun-pointed spectrometer for characterizing hard X-ray emission from solar flares with high cadence. The mission will investigate the processes by which flares accelerate particles to extraordinarily high energies by measuring short spikes in X-ray time profiles. Fine-time-resolution solar science was challenging with previous hard X-ray instruments, which either used time modulation for indirect imaging, did not have a large dynamic range, or experienced pulse pileup during bright flares. IMPRESS will produce high-cadence (40 Hz) spectra from 5 to 100 keV, measuring pulses as short as 0.1 ms, across a wide range of solar flare brightnesses without the use of moveable attenuators. To accomplish this goal, the instrument features an array of scintillators read out by silicon photomultipliers and a high-rate-capable electronics/processing system, housed within a three-axis stabilized, Sun-pointed, 3U CubeSat platform. With a nominal launch in late 2021, IMPRESS will measure flares in the rising phase of Solar Cycle 25.

Amir Caspi