An Investigation of the Thermoluminescence of Fluorite Colored by X-Ray Irradiation

• Published in: The Journal of chemical physics 1953-02, Vol.21 (2), p.223-228
• Main Authors: Hill, John J., Aron, Jack
• Format: Article
• Language: English
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.1698863

The thermoluminescence resulting when calcium fluoride crystals colored by x-ray irradiation are heated, has been investigated in the region from 3200 to 6500A. First, the form of the emission spectrum was determined by the use of a spectrophotometer in conjunction with a photomultiplier tube as a detector, and fifteen emission bands were observed of which seven weak ones had not previously been reported. The peaks of these bands occurred at 3430, 3650, 3710, 3790, 3810, 4150, 4270, 4370, 4570, 4780, 4890, 5230, 5350, 5430, and 5740A. Second, continuous annealing curves or ``glow curves'' were obtained for the strongest emission bands by raising the temperature of the crystal at a constant rate and recording the intensity of the emitted light at the peak of each band. The maxima of the glow curves thus recorded fall into two groups. In group 1, three maxima located at approximately 197, 285, and 310°C were observed. In group 2, five intensity maxima could be distinguished, the lowest occurring at approximately 70°C and the highest at 245°C. The corresponding activation energies were calculated, and in two cases were checked by carrying out the annealing at fixed temperatures. These results are consistent with the assumption that two distinct types of imperfections are responsible for the thermoluminescence of calcium fluoride. The optical absorption appears to be the result of the imperfections associated with group 2.