  A sigma-Fe54.5Cr45.5 samples irradiated in vacuum with 2 MeV Fe3+ ions at
300, 400, 475 and 700 deg C to the maximum dose of 12.5 dpa were studied with
the conversion electron M\"ossbauer spectroscopy (CEMS). The analysis of the
room temperature CEMS spectra revealed an irradiation-induced redistribution of
Fe atoms viz. their number on B and D sites decreased while on A, C and E sites
increased. The degree of the redistribution was found to be proportional to the
number of Fe atoms present on the lattice sites in the non-irradiated samples.
The highest degree of the redistribution was revealed in the sample irradiated
at 300 deg C. No change in the site occupancy was found in the sample
irradiated at 700 deg C.
