Proton Irradiation of 3J Solar Cells at Low Temperature

III-V compound based triple junction solar cells and its component cells have been irradiated with 1 MeV protons at various temperatures, ranging from 100 to 300 K. Degradations of the cell performance (short circuit current I
_SC
, open circuit voltage V
_OC
and maximum power P
_MAX
) have been monitored versus fluence. At low temperature, the rate of degradation of I
_SC
of the bottom cell is very rapid, in such a way that this cell becomes the limiting cell even for low fluences. A possible explanation for the origin of such degradation, based on a non-uniform defect distribution, is suggested.