  Type Ia supernovae are thought to be the outcome of the thermonuclear
explosion of a carbon/oxygen white dwarf in a close binary system. Their
optical light curve is powered by thermalized gamma-rays produced by the
radioactive decay of 56Ni, the most abundant isotope present in the debris. The
maximum and the shape of the light curve strongly depends on the total amount
and distribution of this freshly synthesized isotope, as well as on the
velocity and density distribution of the ejecta. Gamma-rays escaping the ejecta
have the advantage of their lower interaction with the ejecta, the possibility
to distinguish among isotopes and the relative simplicity of their transport
modelling, and can be used as a diagnostic tool for studying the structure of
the exploding star and the characteristics of the explosion, as it has been
proved in the case of SN2014J.
