Cs. Alexander et al., THE TIME AND WAVELENGTH RESPONSE OF PHOTOTRANSFERRED THERMOLUMINESCENCE IN NATURAL AND SYNTHETIC QUARTZ, Radiation measurements, 27(2), 1997, pp. 153-159
Phototransferred thermoluminescence (PTTL) properties from several typ
es of crystalline quartz are presented. Several of the PTTL peaks disp
lay an increase, followed by a decrease, but not necessarily to zero.
The data can be satisfactorily explained by a model which includes the
recombination of electrons and holes during illumination, and two typ
es of recombination center. Consideration of the rate equations descri
bing the phototransfer of charge from deep traps to shallow traps, alo
ng with the wavelength dependence of the photoionization cross-section
, leads to the realization that increasing the illumination intensity
or decreasing the wavelength will have the same effect on the PTTL res
ponse. The wavelength dependence of the PTTL effect can be obtained by
taking the initial slope of the PTTL-vs-illumination-time curve as a
function of wavelength. Using this procedure reveals that only one sou
rce trap is emptying over the wavelength range of green light stimulat
ion, but additional traps become active as the wavelength decreases. O
ver the whole wavelength range used three traps are active, with optic
al threshold energies of 2.37, 2.84 and 3.77 eV. (C) 1997 Elsevier Sci
ence Ltd.