LiMgPO4:Tb,B OSL phosphor – CW and LM OSL studies

In the adjoining paper, the authors have proposed LiMgPO4:Tb,B (LMP) OSL phosphor as a potential alternative to alpha -Al2O3:C for dosimetry applications. This calls for developing an understanding on TL and OSL aspects of this highly sensitive LMP phosphor. CW and LM OSL processes were therefore studied experimentally and kinetic analysis was carried out using theoretical models. Continuous wave (CW) OSL curve for LMP phosphor was found not to follow single decaying exponential implying that the CWOSL curve does not follow first order kinetics. Under pre-readout annealing at 125, 200 and 300 degree C for 10s, the nature of decay profile was unaffected and same holds true for optically bleached CWOSL curves. From linearly modulated (LM) OSL studies, it was found that the shape/geometrical factor mu g was a arrow right 40.72+/-0.03 for wide range of doses (up to 12Gy studied) and peak position "tm " was also independent of dose. The mu g was found to be unaffected with pre-readout annealing at 125, 200 and 300 degree C for 10s and optical bleaching, however it was found that peak position "tm " shifted towards higher side in time with increase of optical bleaching. Dose dependence tests were also carried out for LMOSL curves and it was found that peak position "tm " was independent of dose, which is typical characteristic of curves following first order kinetics. Hence LM-OSL curve might be mixture of more than one component. Further from CW and LM OSL studies, it was also found that the individual contribution from first, second and third TL peak toward OSL is a arrow right 433%, a arrow right 445% and a arrow right 422%, respectively. Traps beyond 350 degree C were found not to contribute towards OSL when stimulated using blue LEDs. In the present paper, the CW and LM OSL processes for LMP phosphor were studied experimentally and their kinetic analysis was carried out.