Exciton-exciton interactions in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>CdWO</mml:mtext></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>irradiated by intense femtosecond vacuum ultraviolet pulses

Kirm, M.; Nagirnyi, V.; Feldbach, E.; Grazia, M. De; Carré, B.; Merdji, H.; Guizard, S.; Geoffroy, G.; Gaudin, J.; Fedorov, N.; Martin, Patrick; Vasil’ev, A. N.; Belsky, A.

doi:10.1103/physrevb.79.233103

Cited by 55 publications

(50 citation statements)

References 21 publications

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“…For LaBr 3, the high frequency and the static dielectric constants are e 1 % 5 and e % 10, respectively; 44 E H ¼ 13:595 eV is the first ionization energy of the hydrogen atom; m Ã m e ¼ 1:323 is the effective electron mass divided by the electron mass; 29 hx 0 ¼ 23:7 meV is the energy of the longitudinal-optical phonon in LaBr 3 . 44 An increase of carrier mobility with temperature increase in our model can only be caused by ionized impurity scattering, 41 which according to Ziman 41 is given by…”

Section: Discussionmentioning

confidence: 99%

“…In a small cylindrical volume with radius r $ 5 nm around the ionization track 1 schematically shown in Fig. 1 on the ps time scale 2 a very high ionization density n > 10 20 e-h/cm 3 of free electrons and holes are created 3,4 that can cause secondary effects. For instance the energy density available is sufficient to displace atoms from their normal lattice positions thus creating radiation damage.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

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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“…We can think that n0 should be about or below the corresponding exciton density of states integrated with the laser spectral distribution. The model is verified experimentally under the conditions of exciton creation in CdWO 4 by 80 fs laser pulses in the region of weak excitonic absorption of the order of 10 2 -10 3 cm…”

Section: Introductionmentioning

confidence: 95%

“…self-trapped excitons) and dipole-dipole energy transfer was obtained in [4,6]. Indexes indicating the types of excitation can be now omitted:…”

Section: Analytical Modelmentioning

confidence: 99%

“…However, in insulators, where only a small radius of self-trapped excitons can be observed at room temperature, much higher densities of electronic excitations are required. Modern coherent sources of radiation such as free electron lasers, powerful tuneable amplified laser systems or those based on high-order harmonic generation are capable of creating electronic excitations at densities up to 10 21 cm 3 in about 10 −13 s. By using such sources the interaction of electronic excitations has been revealed in a sequence of wide band-gap crystals and a Förster theory based model has been developed for describing luminescence yield and decay kinetics in the conditions of crystal excitation by ultra-short high-intensity laser pulses [4][5][6]. However, recent experiments have shown that un-der the conditions of excitation by intense sub-picosecond monochromatic pulses the effective absorption coefficient of CsI crystals becomes dependent on pulse energy [7].…”

Section: Introductionmentioning

confidence: 99%

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Modelling of decay kinetics of self-trapped exciton luminescence in CdWO4 under femtosecond laser excitation in absorption saturation conditions

et al. 2012

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Abstract:The analytical expressions for the three-dimensional spatial distribution of excitons and luminescence decay kinetics of wide band-gap crystals were derived taking into account the saturation effect for absorption near the centre of the incident laser beam with Gaussian transversal profile. The model is verified for the excitonic emission of CdWO 4 crystals under excitation by ultra-short laser pulses in the region of weak excitonic absorption. 78.55.Hx, 78.47.jd, 71.35.Gg, 42.50.Md PACS (2008): Keywords:exciton-exciton interaction • dipole-dipole interaction • excitation density effects • absorption saturation © Versita Sp. z o.o.

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Excitation density, diffusion‐drift, and proportionality in scintillators

Williams

Grim

et al. 2010

Physica Status Solidi (b)

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Phone: þ1 336 758 5132, Fax: þ1 336 758 6142.Stopping of an energetic electron produces a track of high excitation density, especially near its end, and consequent high radial concentration gradient. The effect of high excitation density in promoting nonlinear quenching is generally understood to be a root cause of nonproportionality in scintillators. However, quantitative data on the kinetic rates of nonlinear quenching processes in scintillators are scarce. We report experimental measurements of second-order dipole-dipole rate constants governing the main nonlinear quenching channel in CsI, CsI:Tl, NaI, and NaI:Tl. We also show that the second of the extreme conditions in a track, i.e., radial concentration gradient, gives rise to fast ( picoseconds) diffusion phenomena which act both as a competitor in reducing excitation density during the relevant time of nonlinear quenching, and as a determiner of branching between independent and paired carriers, where the branching ratio changes with dE/dx along the primary electron track. To investigate the interplay of these phenomena in determining nonproportionality of light yield, we use experimentally measured rate constants and mobilities in CsI and NaI to carry out quantitative modeling of diffusion, drift, and nonlinear quenching evaluated spatially and temporally within an electron track which is assumed cylindrical Gaussian in this version of the model. 1 Introduction When an energetic electron is slowed and stopped in a scintillator (or any solid material with a band gap), the track of excitations left behind is characterized by at least two remarkably extreme numbers: (i) very high excitation density and (ii) very large concentration gradient of carriers and/or excitations. The first condition of high excitation density has been recognized for some time as crucial for setting rates of second-order (dipole-dipole) and third-order (Auger) quenching of local light yield in the vicinity of the track. However, with very few exceptions, those rate constants have not been determined. Therefore we present measurements of dipole-dipole quenching rate constants at high excitation density for three halide scintillators in the present work.In addition to the promotion of nonlinear quenching by high excitation density in a track, the high concentration gradient promotes radial diffusion of electrons and holes, which can limit the nonlinear quenching rates by rapidly diluting carrier concentration, and may affect linear rates by setting up charge separation. We show by numerical modeling of the diffusion and quenching processes together

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Exciton-exciton interactions inCdWO4irradiated by intense femtosecond vacuum ultraviolet pulses

Cited by 55 publications

References 21 publications

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

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

Modelling of decay kinetics of self-trapped exciton luminescence in CdWO4 under femtosecond laser excitation in absorption saturation conditions

Excitation density, diffusion‐drift, and proportionality in scintillators

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