Bhatt B C, Dhabekar Bhushan, Kumar Rajesh, Rao T K Gundu, Lakshmanan A R
Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Radiat Prot Dosimetry. 2006;119(1-4):53-6. doi: 10.1093/rpd/nci639. Epub 2006 May 18.
The defect centres formed in the TL phosphor CaSO4:Dy,Ag are studied using the technique of Electron Spin Resonance. The Ag co-doped phosphor exhibits three glow peaks around 130, 220 and 375 degrees C in contrast with the two glow peaks observed in the CaSO4:Dy phosphor at 130 and 220 degrees C at a gamma ray dose of 1Gy. ESR studies show that the additional peak at 375 degrees C correlates with a Ag2+ centre formed due to gamma irradiation and observable only below -170 degrees C. The Ag2+ centre is characterised by an axial g-tensor with principal values g(parallel) = 2.38 and g(perpendicular) = 2.41. ESR studies further indicate that the precursor to a centre observable at low temperature (-170 degrees C) appears to act as the recombination centre for the TL peak at 375 degrees C; this radical is characterised by the g-values g(parallel) = 2.0023 and g(perpendicular) = 2.0038 and is assigned to SO3- radical. It is observed that there is more incorporation of Ag in the CaSO4:Dy system as compared with that in pure CaSO4 system.
利用电子自旋共振技术研究了热释光磷光体CaSO4:Dy,Ag中形成的缺陷中心。与在1Gy的γ射线剂量下，CaSO4:Dy磷光体中在130和220℃观察到的两个发光峰相比，共掺杂Ag的磷光体在130、220和375℃左右呈现三个发光峰。电子自旋共振研究表明，375℃处的额外峰与γ辐照形成的Ag2+中心相关，且仅在-170℃以下可观测到。Ag2+中心的特征是具有轴向g张量，主值g(平行)=2.38和g(垂直)=2.41。电子自旋共振研究进一步表明，在低温（-170℃）下可观测到的一个中心的前体似乎是375℃处热释光峰的复合中心；该自由基的特征g值为g(平行)=2.0023和g(垂直)=2.0038，被归为SO3-自由基。观察到与纯CaSO4体系相比，CaSO4:Dy体系中Ag的掺入更多。
