Comparative Study of Nonproportionality and Electronic Band Structures Features in Scintillator Materials

Setyawan, Wahyu; Gaumé, Romain; Feigelson, Robert S.; Curtarolo, Stefano

doi:10.1109/tns.2009.2027019

Cited by 62 publications

(38 citation statements)

References 51 publications

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“…Proceeding from the above premises, we draw the conclusion that the mobility of the charge carriers (electrons and holes) exerts a significant effect on the nonproportionality [36]. Table 3 presents the values of the nonproportionality of the scintillators in the energy range of 1-80 keV and the effective masses of the carriers [39].…”

Section: Discussionmentioning

confidence: 85%

“…The finite element method is used to solve the diffusion equation and determine the diffusion cur rents, the electric fields, and the local carrier densities in a cylindrical volume of space with a radius of 3 nm around the primary electron track. A change in the track radius from 3 to 5 nm does not lead to an appre ciable effect [39]. The longitudinal diffusion compo nent is ignored, since the typical length of an electron track exceeds the perpendicular component by ~4-5 orders of magnitude [19].…”

Section: Discussionmentioning

confidence: 99%

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Energy dependence of the relative light output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce scintillators

2012

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Abstract-The nonlinear dependence of the relative light output on the energy deposited in single crystal scintillation materials YAlO 3 :Ce (YAP:Ce), Y 2 SiO 5 :Ce (YSO:Ce), and YPO 4 :Ce (YPO:Ce) has been studied. The investigations have been conducted under quasi monochromatic X ray excitation in the energy range of 9.5-100 keV. In addition to the standard technique for measuring the nonproportional scintillator response based on the dependence of the full energy peak position on the energy of incident radiation, a method is proposed for measuring the light output by X ray fluorescence peaks. Using this method for YAP:Ce, it is pos sible to investigate the nonlinear dependence of the light output on the photon energy in the energy range of 2-40 keV. Along with this method, the K dip spectroscopy method has been proposed and tested by measur ing the dependence of the relative light output on the electron energy in the range of 0.1-80.0 keV. The pro cesses resulting in the loss of the scintillation material efficiency at a high ionization density are considered.

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Energy dependence of the relative light output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce scintillators

2012

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“…2,6,21,29,35,36 It is attributed to radiationless electron-hole pair recombination in the regions of a high concentration n(x) of charge carriers along the ionization track as shown in Fig. 1.…”

Section: Discussionmentioning

confidence: 99%

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

Khodyuk

Quarati

Alekhin

et al. 2013

Journal of Applied Physics

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The scintillation response of LaBr 3 :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 c-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% Ce 3þ doped LaBr 3, 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. V C 2013 AIP Publishing LLC. [http://dx

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“…Therefore, advances in the fundamental physics of the complex solid-state phenomena that lead to the emission of scintillation photons are expected to translate directly to science-based performance improvements [1]. This realization has driven significant and recent efforts in developing a better understanding of the condensed matter physics of these materials [2][3][4][5][6][7]. In particular, ever-improving software and hardware capabilities have open the door for first-principles calculations to take a more prominent role in material engineering for improved scintillation performance.…”

Section: Introductionmentioning

confidence: 99%

First-principles search for efficient activators for LaI3

Prange

Gao

et al. 2016

Journal of Luminescence

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a b s t r a c tFirst-principles calculations were performed using density functional theory with Hubbard corrections or hybrid exchange-correlation functionals, as well as the GW approximation, to predict dopants that could serve as efficient activators for LaI 3 , a potentially very bright scintillator for which an appropriate activator has not been identified yet. The dopants considered in this work included a series of lanthanide ions (Ce, Pr, Nd, Eu, Gd, and Tb) and several ns 2 ions (Tl, Pb, Bi, and Sb). Based on both ground-state calculations and constrained DFT calculations to simulate excited states, the trivalent lanthanide dopants were shown not to constitute an improvement over Ce 3 þ , for which experimental data exist, as they showed occupied 4f states below the valence band maximum (VBM) and 5d states above the conduction band maximum (CBM). In contrast, the only divalent lanthanide considered, Eu 2 þ , displayed occupied 4f states within the band gap of the host, but its 5d states were calculated to be above the CBM. Eu 2 þ could nonetheless be exploited as an activator by increasing the band gap energy slightly through substitution of iodide ions by bromide ions. Similar results were obtained for Tl þ . Finally, Bi 3 þ and Sb 3 þ were predicted to be efficient activators in LaI 3 by virtue of having unoccupied p states below the CBM, which can serve as electron traps and can combine with holes at the VBM to form localized luminescence centers. Therefore, Bi-and Sb-doped LaI 3 should be grown and tested experimentally. Comparison with empirical relationships of the relative positions of the energy levels of rare-earth dopants and implications for efficient doping schemes and scintillation mechanisms in LaI 3 are also discussed.

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Comparative Study of Nonproportionality and Electronic Band Structures Features in Scintillator Materials

Cited by 62 publications

References 51 publications

Energy dependence of the relative light output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce scintillators

Energy dependence of the relative light output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce scintillators

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

First-principles search for efficient activators for LaI3

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