Your NaI detector is rubbish for spectroscopy because of the lousy resolution. High resolution studies in the UK in the 80s corrected several misapprehensions

Your NaI detector is rubbish for spectroscopy because of the lousy resolution. High resolution studies in the UK in the 80s corrected several misapprehensions about the physics from attempted spectroscopy with NaI. It was only useful for Compton suppression as far as we were concerned, and soon replaced for that.