Optical absorption and thermoluminescence in single NaCl:Cu crystals exposed to 60Co and UV light.
Optical absorption (OA) and thermally stimulated luminescence measurements were performed on NaCl:Cu+(0.04 and 0.08%) crystals blocks grown by the Czochralski technique. The NaCl:Cu+ crystals were exposed to gamma rays from a 60Co source (0.954-30 kGy) as well as UV radiation. The radiation-induced defects were mainly F, Cu- and Cu+ centres, with absorption bands located at 464, 256.7 and 236 nm, respectively. The absorption bands were found to be independent of the Cu impurity concentration. As the gamma-dose irradiation increased, the absorption band at 256.7 nm decreased while the band at 236.3 nm increased highly along with the 256.7 nm band. The F-centres produced at high gamma-radiation dose while thermally bleached showed an increase of the Cu+ OA bands with a simultaneous decrease of Cu- absorption band. The bleaching with F-light showed the participation of the F centre generated by gamma radiation on the ion valence changes of the doping impurity as well as on the TL phenomenon. The TL measurements in NaCl:Cu crystals with both impurity concentrations demonstrated that the Cu+ concentration has a strong influence on the intensity and shape of the glow peaks.
Cruz-Zaragoza
E
E
Instituto de Ciencias Nucleares UNAM, A. Postal 70-543, México D.F., México. eecruz@nucleares.unam.mx
Barboza-Flores
M
M
Chernov
V
V
Meléndrez
R
R
Ramos B
S
S
Negrón-Mendoza
A
A
Hernández
J M
JM
Murrieta
H
H
D003037:Cobalt Radioisotopes / Q000032:analysis*; D003300:Copper / Q000737:chemistry* / Q000528:radiation effects; D003460:Crystallization / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005720:Gamma Rays; D008422:Materials Testing; D055095:Optics and Photonics; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry* / Q000528:radiation effects; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation* / Q000379:methods; D014466:Ultraviolet Rays
D003037:Cobalt Radioisotopes; D012965:Sodium Chloride; D003300:Copper