We had compared dose dependence at 80 K of yellow and UV
luminescence for γ-irradiated sample and annealed sample,
Fig. 13. Remind that UV luminescence could be excited with photons
higher than 7 eV and better is observable at low temperatures.
For compared cases the UV luminescence was excited with
F2 (157 nm) laser and the yellow luminescence was excited with
ArF (193 nm) laser. UV luminescence dose behavior is practically
independent of annealing procedure whereas yellow luminescence
dose dependence is different in annealed and not annealed
(γ-irradiated) sample. It is seen that yellow luminescence exhibits
similar behavior to the case of 293 K, presented in Fig. 12, that in
annealed sample intensity drops down with dose whereas for γ-
irradiated sample little changing at high doses. Difference with
293 K is in initial part of dose curve. At 80 K intensity of yellow
luminescence grows in time of 10 min of irradiation, whereas at
293 K growth is observed only for γ-irradiated sample, but
annealed sample intensity drops down already in initial stage of
irradiation, Fig. 13. That could show on different processes taking
place in sample at high and low temperatures for observation of
yellow luminescence. Also from data in Fig. 13 we can conclude
that centers responsible for UV luminescence and responsible for
yellow luminescence participate in different processes. Lack of TSL
peak at 55 K for UV luminescence underlines this point of view,