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Proceedings Paper

Radiation response of inorganic scintillators: insights from Monte Carlo simulations
Author(s): Micah Prange; Dangxin Wu; Yulong Xie; Luke W. Campbell; Fei Gao; Sebastien Kerisit
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Paper Abstract

The spatial and temporal scales of hot particle thermalization in inorganic scintillators are critical factors determining the extent of second- and third-order nonlinear quenching in regions with high densities of electron-hole pairs, which, in turn, leads to the light yield nonproportionality observed, to some degree, for all inorganic scintillators. Therefore, kinetic Monte Carlo simulations were performed to calculate the distances traveled by hot electrons and holes as well as the time required for the particles to reach thermal energy following γ-ray irradiation. CsI, a common scintillator from the alkali halide class of materials, was used as a model system. Two models of quasi-particle dispersion were evaluated, namely, the effective mass approximation model and a model that relied on the group velocities of electrons and holes determined from band structure calculations. Both models predicted rapid electron-hole pair recombination over short distances (a few nanometers) as well as a significant extent of charge separation between electrons and holes that did not recombine and reached thermal energy. However, the effective mass approximation model predicted much longer electron thermalization distances and times than the group velocity model. Comparison with limited experimental data suggested that the group velocity model provided more accurate predictions. Nonetheless, both models indicated that hole thermalization is faster than electron thermalization and thus is likely to be an important factor determining the extent of third-order nonlinear quenching in high-density regions. The merits of different models of quasi-particle dispersion are also discussed.

Paper Details

Date Published: 9 September 2014
PDF: 17 pages
Proc. SPIE 9213, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVI, 92130L (9 September 2014); doi: 10.1117/12.2063818
Show Author Affiliations
Micah Prange, Pacific Northwest National Lab. (United States)
Dangxin Wu, Pacific Northwest National Lab. (United States)
Yulong Xie, Pacific Northwest National Lab. (United States)
Luke W. Campbell, Pacific Northwest National Lab. (United States)
Fei Gao, Pacific Northwest National Lab. (United States)
Sebastien Kerisit, Pacific Northwest National Lab. (United States)


Published in SPIE Proceedings Vol. 9213:
Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVI
Arnold Burger; Larry Franks; Ralph B. James; Michael Fiederle, Editor(s)

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