The Spectrometer/Telescope for Imaging X-rays (STIX) will look at solar flares across the hard X-ray window provided by the Solar Orbiter cluster. Similarly to the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), STIX is a visibility-based imaging instrument, which will ask for Fourier-based image reconstruction methods. However, in this paper we show that, as for RHESSI, also for STIX count-based imaging is possible. Specifically, here we introduce and illustrate a mathematical model that mimics the STIX data formation process as a projection from the incoming photon flux into a vector made of 120 count components. Then we test the reliability of Expectation Maximization for image reconstruction in the case of several simulated configurations typical of flare morphology.
@article{arxiv.1902.08190,
title = {A count-based imaging model for the Spectrometer/Telescope for Imaging X-rays (STIX) in Solar Orbiter},
author = {Paolo Massa and Michele Piana and Anna Maria Massone and Federico Benvenuto},
journal= {arXiv preprint arXiv:1902.08190},
year = {2019}
}