Relative hcp thermoluminescence and optical absorption efficiencies: The demise of track structure theory

The thermoluminescence relative efficiency, ηTST, of LiF:Mg,Ti and LiF:Mg,Cu,P following heavy charged particle irradiation is calculated using track structure theory and compared with experimental measurements. The calculations use both 60Co generated values of secondary electron dose response and values of the dose response at lower photon energies. In both materials there is poor agreement with experiment. Optical absorption relative efficiencies are also in disagreement. For the F band, ηexpt'l/ηTST = 2.0 and 2.6 for He ions and protons, respectively. The values of ηexpt'l/ηTST for the 4.0-eV band, resulted in 0.18 (protons) and <0.12 (He ions). An indication that the 4.0-eV trapping structure is either destroyed or de-populated during the heavy charged particle (HCP) slowing down. The large deviations of ηexpt'l/ηHCP from unity demonstrate that TST, which predicts HCP induced radiation effects from the exclusive action of the released secondary electrons, is woefully inadequate.