Hi, I was doing a measurement on a Cs-137 source, strong enough so that my detector registers a sum peak. I cant get my head around A, the peak at ~80 keV.. I get B (backscatter peak), C(compton edge) and D total abs.peak. I tried with a weaker Cs-137 and I saw the 35keV (Ba) but no ~80keV. Any ideas? Thank you very much!