Local lattice relaxation around Tl substitutional impurities in a NaI(Tl) scintillator crystal
Journal article, 2020
A Thallium (Tl) L3-edge x-ray absorption experiment was performed on a NaI(Tl) scintillation crystal at room temperature using fluorescence detection. The data analysis provides clear evidence for a ≃5 % average bond length expansion of the first shell I atoms surrounding the Tl impurities with respect to the Na-I crystallographic bond-length. Possible evidence for a slight expansion of the second and third shells is obtained. The data are compatible with a previous experiment performed at liquid nitrogen temperature considering thermal expansion. A critical review of existing theoretical predictions and density functional theory supercell calculations support present findings and suggest the opportunity to perform a high quality temperature dependent experiment.
XAFS
Scintillator crystal
NaI(Tl)
Impurity site
Author
A. Filipponi
University of L'Aquila
Laboratori Nazionali del Gran Sasso
G. Profeta
Laboratori Nazionali del Gran Sasso
University of L'Aquila
N. Di Marco
Gran Sasso Science Institute (GSSI)
Laboratori Nazionali del Gran Sasso
Vanessa Zema
Gran Sasso Science Institute (GSSI)
Chalmers, Physics, Subatomic and Plasma Physics
K. Schäffner
Max Planck Society
F. Reindl
Austrian Academy of Sciences
Atominstitut der Osterreichischen Universitaten
Messaoud Harfouche
Next to Princess Rahma University College
A. Trapananti
National Institute for Nuclear Physics
University of Camerino
A. Di Cicco
University of Camerino
National Institute for Nuclear Physics
Radiation Physics and Chemistry
0969-806X (ISSN) 18790895 (eISSN)
Vol. 177 108992Subject Categories (SSIF 2011)
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1016/j.radphyschem.2020.108992