Open AccessMultiple thermoluminescence glow peaks and afterglow suppression in CsI:Tl co-doped with Eu2+or Yb2+
Author(s) -
R.H. Bartram,
L.A. Kappers,
Douglas S. Hamilton,
C. Brecher,
E.E. Ovechkina,
Stuart Miller,
Vivek V. Nagarkar
Publication year - 2015
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/80/1/012003
Subject(s) - afterglow , thermoluminescence , ionic radius , scintillator , lanthanide , doping , ionic bonding , materials science , excited state , dopant , analytical chemistry (journal) , atomic physics , europium , photoluminescence , luminescence , ion , chemistry , physics , optics , optoelectronics , astronomy , detector , gamma ray burst , organic chemistry , chromatography
CsI:Tl is a widely utilized scintillator material with many desirable properties but its applicability is limited by persistent afterglow. However, effective afterglow suppression has been achieved by co-doping with divalent lanthanides. The present report is concerned with observation of multiple thermoluminescence glow peaks in CsI:Tl,Eu and CsI:Tl,Yb, attributed to varying distributions of charge-compensating cation vacancies relative to divalent lanthanide co-dopants, and the subsequent modification of these distributions by repeated observations. It is observed that Yb2+ provides a slightly shallower electron trap than Eu2+, and that it can occupy a face-centered position by virtue of its relatively small ionic radius; the latter observation is confirmed by electrostatic calculations. It is also found that repeated observation of thermoluminescence in these materials has a modest adverse effect on afterglow suppression.