Expected effective detector area with respect to the direction of the incident gamma radiation for various energy ranges: 40−110 keV (top left panel), 110−370 keV (top right panel), 370−630 keV (bottom left panel) and 630−890 keV (bottom right panel). These ϑ (zenith angle, vertical) and φ (azimuth angle, horizontal) plots are displayed in the reference frame of the satellite where Z+ axis (i.e., the face of the detector) is equivalent to the ϑ = 180° angle at the top pole of spherical plots (see also Fig. 5). It is clear that at lower energies, the satellite itself has a transparency around 60−70% while at higher energies it is almost transparent and the structure of the plots is dominated by the geometric cross section of the scintillator crystal.