In this work, we report the analysis of TL features of CVD diamond samples
after exposure to Sr-90/(90)Yr beta particles.
The glow curves have been analysed in order to determine the trapping kinet
ics and the activation energies of the trapping levels. They have been inte
rpreted as due to a first-order trap emptying process with activation energ
ies ranging from 0.98 to 1.12 eV.
Owing to the great practical interest of diamond in radiotherapy, we: have
explored the application of CVD diamond as TL dosimeter. The dose-response
of the CVD diamond film to beta irradiation was investigated at clinical ap
plication doses and compared with the response of LiF TL100 samples.
Moreover, measurements of charge pulses induced by 5.4 MeV alpha particles
were carried out in order to investigate the effect of beta particle pre-ir
radiation (or 'priming') on the charge collection efficiency. The saturatio
n of hole trapping levels evaluated by glow curve analysis was shown to be
strictly related to the improvement of charge collection efficiency. A mode
l of the charge carrier dynamics is also presented which accounts for the o
ptical bleaching of glow curve and alpha particle spectra. (C) 1999 Elsevie
r Science S.A. All rights reserved.