The Reuven Ramaty High Energy Solar Spectroscopic Imager
(RHESSI) was designed to measure hard X-rays and γ-rays from solar flares. With its big detection area and thin side shielding it also proved to be well suited for studying
Gamma Ray Bursts (GRB). Polarization analysis is feasible as well, due to a big modulation factor (MF), though serious constraints on the minimum detectable polarization
(MDP) come from detection efficiency of double scattered photons. More constraints are given by background of accidental and real coincidences