Radsafers, Does anyone have a reference (short of contacting each manufacturer) on the relative beta energy response (mR/hr per mrad/hr) of various ion chamber instruments (Victoreen 450, 450P, RO-2, etc) to Sr-90/Y-90? Any help would be appreciated. R. Charris charrisR@51mdg.osan.af.mil Noel M: No, I'm not very bored. ----My employer will disavow any knowledge of my actions------