On the Luminescence Minimum in Certain Scintillator Solutions

Several scintillator solutions have been examined for the luminescence minimum previously reported for the case of Co60 gamma irradiated cyclohexane+benzene+p-terphenyl with oxygen present. The minimum is shown to be dependent on the nature of the solvents and of the quencher. A satisfactory interpretation of the data involves the notion of energy transfer from molecules of the less-efficient (``common'') solvent to the molecules of the more efficient (``better'') solvent and thence to the scintillator. The latter transfer appears to involve more than one molecule of the solvent. A suggested model of the quenching process explains the existence of two classes of quenchers, one of which does not give a minimum.