Analysis of Gamma Ray Scintillation Spectra for Quantitative Photon Intensities

The various considerations necessary for conversion of the pulse height spectrum from NaI(Tl) spectrometers to photon intensity distributions are discussed. Some of these are: 1) resolution and efficiency of the crystal; 2) summing of cascade gamma rays; 3) source geometry and self-absorption; and 4) handling of positron emitters. A straightforward empirical method for subtracting the Compton distributions associated with the various gamma rays in a complex spectrum is indicated and the logical extension to continuous photon distributions is discussed.