Measurements of relative photo-ionization cross-section in indigeneously developed anion defective α-Al2O3

The relative photo-ionization cross-section at various stimulating light photons flux was measured for indigenously developed anion defective crystalline α-Al2O3 and commercially available grown single crystal α-Al2O3:C to explore the possibility of indigenous samples in personnel and environmental monitoring. The effect of variation of stimulating light intensity on OSL properties of the α-Al2O3 is studied. The photo-ionization cross-section of the developed samples is compared with the commercial samples and it is found that developed sample differs in qualitative as well as quantitative way from commercially available α-Al2O3:C. It is found that the photo-excitation rate in both α-Al2O3 increases with the increase in stimulating light flux. However, the photo-ionization cross-section of developed anion defective crystalline Al2O3 is found to be approximately twice that of standard single crystal α-Al2O3:C for the Ip =475nm (Dl=50nm) stimulation wavelength. This implies that, OSL read out of the developed anion defective Al2O3 samples could be carried out twice as faster than standard single crystal α-Al2O3:C with same stimulating light power. The study of photo ionization cross section also points out that the origin of slow OSL component is possibly due to shallow defect trap levels which are not reflected in TL phenomenon of α-Al2O3:C. (author)