The role of diffusion, migration and long-range interaction in energy transfer and quenching processes in an organic liquid scintillator

The energy transfer rate parameter K3 and the quenching rate parameter K7b are determined in a liquid scintillator system consisting of 2,5-di-[5-tertbutyl-2-benzoxazolyl]-thiophene (BBOT) as solute, toluene as solvent and bromobenzene as external solvent quencher in three different media; neat toluene (TN), dilute mixture 1:9 by volume fraction to toluene to cyclohexane (TC) and toluene to liquid paraffin (TP), in the temperature range 20o-70oC (viscosity range 0.35-39.0 cp). The results are discussed in terms of the role of diffusion, migration and long-range dipole-dipole interaction of Forster type in these three systems. (Author)