Energy resolution and related charge carrier mobility in LaBr3:Ce scintillators

Khodyuk, I.V.; Quarati, F.G.A.; Alekhin, M.S.; Dorenbos, P.

doi:doi:10.1063/1.4823737

Energy resolution and related charge carrier mobility in LaBr3:Ce scintillators

Title

Energy resolution and related charge carrier mobility in LaBr3:Ce scintillators

Author

Khodyuk, I.V.
Quarati, F.G.A.
Alekhin, M.S.
Dorenbos, P.

Faculty

Applied Sciences

Department

RST/Radiation, Science and Technology

Date

2013-09-27

Abstract

The scintillation response of LaBr3:Ce scintillation crystals was studied as function of temperature and Ce concentration with synchrotron X-rays between 9?keV and 100?keV. The results were analyzed using the theory of carrier transport in wide band gap semiconductors to gain new insights into charge carrier generation, diffusion, and capture mechanisms. Their influence on the efficiency of energy transfer and conversion from X-ray or ?-ray photon to optical photons and therefore on the energy resolution of lanthanum halide scintillators was studied. From this, we will propose that scattering of carriers by both the lattice phonons and by ionized impurities are key processes determining the temperature dependence of carrier mobility and ultimately the scintillation efficiency and energy resolution. When assuming about 100?ppm ionized impurity concentration in 0.2% Ce3+ doped LaBr3, mobilities are such that we can reproduce the observed temperature dependence of the energy resolution, and in particular, the minimum in resolution near room temperature is reproduced.

Subject

charge carriers
ionization
carrier mobility
photons
ionizing radiation
phonons
diffusion
doping
carrier scattering
electron hole