Advanced spectroscopic investigation of color centers in LiF crystals exposed to 6 MV x-ray clinical beams.

Vincenti M.A., Bonfigli F., Montereali R.M., Piccinini M., Khan R., Villarreal-Barajas J.E.
  Mercoledì 28/09   10:00 - 13:00   Edificio Psicologia 2 - Aula 2B   II - Fisica della materia
LiF crystals were irradiated in a dose range (absorbed dose to water) of 1--100 Gy by 6 MV x-rays produced by a clinical linear accelerator. Their optical absorption spectra show stable formation of primary F defects, but not the M absorption band due to aggregate $F_{2}$ and $F_{3}^{+}$ color centers. Photoluminescence spectra, excited at 457.9 nm, clearly exhibit the $F_{2}$ and $F_{3}^{+}$ visible broad emission bands. The integrated photoluminescence intensity, measured using a fluorescence optical microscope, shows a linear behaviour as a function of the irradiation dose. These preliminary results encourage further investigation of nominally pure LiF crystals as clinical dosemeters.