This is an IDL saveset file with survival probabilities calculated for 
IBEX-Hi maps.

To read via IDL:

IDL>restore, "filename"

where "filename" is the full path of the survival probability .sav file.

The data structure is:
sv.surmask[30, 60, 5, 6]

referring to the 6 degree all-sky maps (30 x 60), 5 energy channels, 
and 6 6-months maps.