Kinetic Monte Carlo simulations of excitation density dependent scintillation in CsI and CsI(Tl)

Nonlinear quenching of electron–hole pairs in the denser regions of ionization tracks created by γ‐ray and high‐energy electrons is a likely cause of the light yield non‐proportionality of many inorganic scintillators. Therefore, kinetic Monte Carlo (KMC) simulations were carried out to investigate...

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Bibliographic Details
Published in:physica status solidi (b) 2013-08, Vol.250 (8), p.1532-1540
Main Authors: Wang, Zhiguo, Williams, Richard T., Grim, Joel Q., Gao, Fei, Kerisit, Sebastien
Format: Article
Language:English
Subjects:
inorganic scintillators
kinetic Monte Carlo
non-proportionality
nonlinear quenching
scintillation mechanisms
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Summary:Nonlinear quenching of electron–hole pairs in the denser regions of ionization tracks created by γ‐ray and high‐energy electrons is a likely cause of the light yield non‐proportionality of many inorganic scintillators. Therefore, kinetic Monte Carlo (KMC) simulations were carried out to investigate the scintillation properties of pure and thallium‐doped CsI as a function of electron–hole pair density. The availability of recent experimental data on the excitation density dependence of the light yield of CsI following ultraviolet excitation allowed for an improved parameterization of the interactions between self‐trapped excitons (STE) in the KMC model via dipole–dipole Förster transfer. The KMC simulations reveal that nonlinear quenching occurs very rapidly (within a few picoseconds) in the early stages of the scintillation process. In addition, the simulations predict that the concentration of thallium activators can affect the extent of nonlinear quenching as it has a direct influence on the STE density through STE dissociation and electron scavenging. This improved model will enable more realistic simulations of the non‐proportional γ‐ray and electron response of inorganic scintillators.
ISSN:0370-1972
1521-3951
DOI:10.1002/pssb.201248587