The successful results on the spectral response matrix don't exploit completely GRBM potential. A more detailed study of crystal non-linearity phenomena and of escape and backscattering effects is already under development via analytical methods. The count deficit in the Crab spectrum (chapter 4) is explained at 50% level by this more precise modeling. A better modeling of the materials transparencies at low energies and the use of the Monte Carlo software will allow for a more precise description of these effects, in particular between 40 and 70 keV.
At higher energies a first application of the Monte Carlo has already produced a correction of the photo peak efficiency. Unfortunately the data from the Crab occultation are very reliable at lower energies, when the source is relatively strong versus the background. At higher energies the application of the earth Occultation Technique requires a better, channel by channel, modeling of the background variation: a first improvement has been already done for the analysis of GRB970228, detected soon after a SAGA passage.
A further development towards a better knowledge of the response matrix should be pushed by a recently defined activity of conjunct analysis of BATSE and SAX/WFC+GRBM data of very luminous GRB. While the BATSE/GRBM comparison has been (see Chapter 4) successful for integrated bands, the analysis of multichannel spectra should provide a good cross calibration of the two experiments.