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|Title: ||ESR and TL mechanism in CaSO4 : Ag co-doped phosphors|
|Authors: ||DHABEKAR, B|
|Issue Date: ||2006|
|Publisher: ||IOP PUBLISHING LTD|
|Citation: ||JOURNAL OF PHYSICS D-APPLIED PHYSICS, 39(12), 2488-2493|
|Abstract: ||Thermoluminescence (TL) studies have been carried out on CaSO4 : Mn, CaSO4 : Ag, Mn, CaSO4 : Ag, Nd, CaSO4 : Ag, Mn, Nd, CaSO4 : Ag, Zr and CaSO4 : Ag, Mn, Zr phosphors. It is found that TL at 360 degrees C in CaSO4 : Ag, Mn, Nd is about 40 times that of CaSO4 : Ag, Mn and about 170 times that of CaSO4 : Ag, Nd. This shows that the presence of an efficient luminescent centre (Mn2+) as well as a trivalent impurity (such as Nd3+ or Y3+) is important for enhancement of TL at 360 degrees C in the CaSO4 : Ag, Mn, Nd phosphor system. Electron spin resonance (ESR) studies show that the peak at 360 degrees C correlates with an Ag2+ centre formed due to gamma-irradiation and observable only below -170 degrees C. The Ag2+ centre is characterized by an axial g-tensor with principal values g(parallel to) = 2.38 and g(perpendicular to) = 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 360 degrees C. The low temperature centre is characterized by the g-values g(vertical bar vertical bar) = 2.0023 and g(perpendicular to) = 2.0038 and is assigned to the SO3- radical.|
|Appears in Collections:||Article|
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