Charge carrier and exciton dynamics in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>LaBr</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo>:</mml:mo><mml:msup><mml:mi>Ce</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>scintillators: Experiment and model

Bizarri, Grégory; Dorenbos, P.

doi:10.1103/physrevb.75.184302

Cited by 88 publications

(67 citation statements)

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“…Commercial-grade LaBr 3 :Ce(5%) has a fast decay time of ∼16 ns (Bizarri and Dorenbos 2007), a high light yield of ∼70.000 photons MeV −1 (de Haas and Dorenbos 2008), an excellent energy resolution of ∼2.6% FWHM at 662 keV (Drozdowski et al 2007), a mass density of 5.1 g cm −3 and an effective atomic number of 46.9 (van Eijk 2002). To optimally benefit from the advantages of LaBr 3 :Ce in a PET detector, the scintillation light should be read out using a photosensor with fast response and high photodetection efficiency (PDE) at the LaBr 3 :Ce emission wavelengths (∼380 nm).…”

Section: Introductionmentioning

confidence: 99%

LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

et al. 2010

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The use of time-of-flight (TOF) information in positron emission tomography (PET) enables significant improvement in image noise properties and, therefore, lesion detection. Silicon photomultipliers (SiPMs) are solid-state photosensors that have several advantages over photomultiplier tubes (PMTs). SiPMs are small, essentially transparent to 511 keV gamma rays and insensitive to magnetic fields. This enables novel detector designs aimed at e.g. compactness, high resolution, depth-of-interaction (DOI) correction and MRI compatibility. The goal of the present work is to study the timing performance of SiPMs in combination with LaBr 3 :Ce(5%), a relatively new scintillator with promising characteristics for TOF-PET. Measurements were performed with two, bare, 3 mm × 3 mm × 5 mm LaBr 3 :Ce(5%) crystals, each coupled to a 3 mm × 3 mm SiPM. Using a 22 Na point source placed at various positions in between the two detectors, a coincidence resolving time (CRT) of ∼100 ps FWHM for 511 keV annihilation photon pairs was achieved, corresponding to a TOF positioning resolution of ∼15 mm FWHM. At the same time, pulse height spectra with well-resolved full-energy peaks were obtained. To our knowledge this is the best CRT reported for SiPM-based scintillation detectors to date. It is concluded that SiPM-based scintillation detectors can provide timing resolutions at least as good as detectors based on PMTs.

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Section: Introductionmentioning

confidence: 99%

LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

et al. 2010

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“…1). The spectra contain overlap ping bands at 356 and 382 nm, which are formed by typical radiative d f transitions in the Ce 3+ ion [1,5,6]. The XL efficiency of the Hf doped crystals remains almost unchanged.…”

Section: Resultsmentioning

confidence: 99%

“…Owing to the high energy resolution and good radiation resistance, these crystals can be used in spectrometry and various medical applications [1][2][3]. The mechanism of the formation of scintillation pulses in these crystals has been studied in sufficient detail due to investigations of the luminescence under excitation of different types, as well as due to research in electronic excitation energy transfer to Ce 3+ impu rity centers [4][5][6][7]. At present, the main problem is to investigate the energy nonproportionality of the light yield in the gamma ray spectral range and, especially, in the X ray region of the spectrum [8,9].…”

Section: Introductionmentioning

confidence: 99%

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

2014

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Abstract-This study has been carried out using synchrotron radiation, time resolved luminescence ultraviolet and vacuum ultraviolet spectroscopy, optical absorption spectroscopy, and thermal activation spectroscopy. It has been found that, in scintillation spectrometric crystals LaBr 3 : Ce,Hf characterized by a low hygroscopicity, along with Ce 3+ centers in regular lattice sites, there are Ce 3+ centers located in the vicinity of the defects of the crystal structure. It has also been found that the studied crystals exhibit photoluminescence (PL) of new point defects responsible for a broad band at wavelengths of 500-600 nm in the PL spectra. The minimum energy of interband transitions in LaBr 3 is estimated as E g ~ 6.2 eV. The effect of multiplication of electronic excitations has been observed in the range of PL excitation energies higher than 13 eV (more than 2E g ). Thermal activation studies have revealed channels of electronic excitation energy transfer to Ce 3+ impurity centers.

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“…At high concentration of Ce 3þ in LaBr 3 essential part of the charge carriers can be promptly removed from the diffusionquenching process. According to Bizarri and Dorenbos,39 carriers can be sequentially captured by Ce 3þ or form selftrapped excitons (STE) which transfer their energy to Ce 3þ through thermally activated migration or directly. These effects can lead to a significant difference of quenching probability at low Ce concentration, 0.2%, and at high concentrations 5% and 30%.The minimum in r e for LaBr 3 :0.2% Ce 3þ in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The calculations do not incorporate any carrier trapping 39 and also it was assumed that all charge carriers are thermalized instantly 42,43 after creation in the ionization track. However, recent theoretical studies 35,45 suggest that also non-thermalized carriers play an important role in carrier and phonon transport in scintillators.…”

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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Charge carrier and exciton dynamics inLaBr3:Ce3+scintillators: Experiment and model

Cited by 88 publications

References 16 publications

LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

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

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Charge carrier and exciton dynamics inLaBr3:Ce3+scintillators: Experiment and model

Cited by 88 publications

References 16 publications

LaBr3:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

LaBr3:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

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

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LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time

LaBr₃:Ce and SiPMs for time-of-flight PET: achieving 100 ps coincidence resolving time