Study for Gamma Ray Spectra of Cascading Decay

Relative intensity to the Single peaks and true sum peaks lO the elements of cascading decay of gamma-rays as 60 co and 88 Y have been measured for different point source -detector distances by using 3 ☓ 3 nall(Tl) detector into two difierent methods. These methods give a good information to distinguish between single and true sum peaks especially in analysis a complex pulse height spectrum : where the relative intensity for tn.e sum peak varies wtrh source detector distance while it is independent for single peak. The results of two the methods are in fair agreement.