  High energy emissions from supernovae (SNe), originated from newly formed
radioactive species, provide direct evidence of nucleosynthesis at SN
explosions. However, observational difficulties in the MeV range have so far
allowed the signal detected only from the extremely nearby core-collapse SN
1987A. No solid detection has been reported for thermonuclear SNe Ia, despite
the importance of the direct confirmation of the formation of 56Ni, which is
believed to be a key ingredient in their nature as distance indicators. In this
paper, we show that the new generation hard X-ray and soft gamma-ray
instruments, on board Astro-H and NuStar, are capable of detecting the signal,
at least at a pace of once in a few years, opening up this new window for
studying SN explosion and nucleosynthesis.
