I'm currently doing a spectroscopy lab where you use a scintillator and Cs-137 to obtain a Cs-137 spectrum. I calibrated this spectrum using the known gamma energy for Cs-137 at 662 Kev at the photo peak. I am now trying to use this calibration for a Co-60 spectrum. The problem is that when I obtained my Cs-137 Spectrum I had the coarse gain at x16 and fine gain at x5. When I was taking data for the Co-60 I had to adjust the coarse gain to x8 and fine gain to x3.5. I understand the coarse gain is half that of the Cs-137 but how would I factor in the fine gain? For example for Cs-137 the photo peak was on channel 935 at 662Kev. So if I adjust the gain by half then 662Kev should correspond to channel 467.5 for the Co-60 spectrum. How does the fine gain adjust the factor?