26 results on '"Babin, Vladimir"'
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2. Charge trapping and luminescence of the mixed size CsPbBr3 particles grown in one batch.
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Buryi, Maksym, Babin, Vladimir, Děcká, Kateřina, Ridzoňová, Katarína, Neykova, Neda, Hájek, František, Velkov, Zhivko, Remeš, Zdeněk, Tomala, Robert, Socha, Paweł, Bartosiewicz, Karol, Hostinský, Tomáš, Mošner, Petr, Yamamoto, Tomoyuki, Ma, Chong-Geng, and Brik, Mikhail G.
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QUANTUM dots , *LUMINESCENCE , *ELECTRON traps , *ELECTRON paramagnetic resonance , *AMORPHOUS substances , *THERMAL electrons , *SPIN crossover - Abstract
Cesium lead bromide (CsPbBr 3 , CPB) powder formed by micro-, nanocrystals (MC, NC) and quantum dots (QD) was synthesized as free-standing and polystyrene covered. Luminescence was multicomponent, in general, ranging from below 1.9 eV up to about 2.6 eV. The ultrafast decay kinetics exhibited strong decay time component with the value of 260 ps. Electron paramagnetic resonance (EPR) revealed surface defects like O 2 − and some spin transitions most likely originating from some complex defect, supposedly F-V k (H) dimer center under the constant ultraviolet (UV) light irradiation at the temperature T = 10 K. The thermal release of the electrons from the O 2 − center was correlated with the 117 K thermally stimulated luminescence (TSL) peak. Coating with polystyrene resulted in the about doubly increased decay time of luminescence. The O 2 − and F-V k (H) EPR resonances were not observed as well. The TSL peak which might be ascribed to the O 2 − was not clearly detected anymore. The glow curve was composed of one very broad peak typical for the amorphous materials. At the same time, the polystyrene prevented the MCs creation. The existence of charge/energy transfer between the CPB and polystyrene due to the chemical bonding was assumed and confirmed also by calculations. [Display omitted] • EPR, TSL and RL study of charge trapping and luminescence in CsPbBr 3. • Charge/energy transfer was detected. • O 2 − -related electron trapping center was revealed in these crystals. • TSL peak was correlated to the release of electrons from the O 2 − surface center. • Complex bromine vacancy-related charge trapping center was observed. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Improvement of the growth of Li4SiO4 single crystals for neutron detection and their scintillation and luminescence properties.
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Pejchal, Jan, Babin, Vladimir, Beitlerova, Alena, Kurosawa, Shunsuke, Yokota, Yuui, Yoshikawa, Akira, and Nikl, Martin
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LITHIUM compounds , *NEUTRON counters , *SINGLE crystals , *CRYSTAL growth , *SCINTILLATORS , *LUMINESCENCE , *EVAPORATION (Chemistry) - Abstract
We have investigated Li 4 SiO 4 scintillation crystals for their possible application in neutron detection due to high Li content and low density of 2.35 g/cm 3 . The micro-pulling-down method employing the Ir crucible and afterheater was optimized for crystal growth of Li 4 SiO 4 taking into account the Li evaporation. To grow high-quality crack-free single crystals, the heating power was increased to establish milder temperature gradient, thicker meniscus, smaller crystal diameter and resulting smaller stress in the as-grown crystals. The undoped, Ti-, Cr-, and Al- doped crystals were prepared and studied. Radioluminescence measurements under X-ray excitation showed quite high overall scintillation efficiency of the Ti-doped sample reaching as high as 250% of that of Bi 4 Ge 3 O 12 reference scintillator. The emission spectrum was dominated by one broad band peaking at 350 nm related to Ti 4+ impurity. Reasonable light yield of 10000 photons/neutron was found. However, its long decay time of 54 μs might be a limitation especially for high counting rate applications. The overall scintillation efficiency of the Cr 3+ sample was much lower and the spectrum shows one broad peak at 463 nm which does not correspond to Cr 3+ luminescence. The radioluminescence spectrum of the Al-doped sample resembled to that of the Ti-doped one, just its magnitude is considerably lower, which was explained by Ti contamination. Peculiarities and optimization of crystal growth and a preliminary sketch of luminescence mechanisms and dopant incorporation are discussed. [ABSTRACT FROM AUTHOR]
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- 2017
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4. The Stable Ce^4 + Center: A New Tool to Optimize Ce-Doped Oxide Scintillators.
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Nikl, Martin, Babin, Vladimir, Pejchal, Jan, Laguta, Valentin V., Buryi, Maksym, Mares, Jiri A., Kamada, Kei, Kurosawa, Shunsuke, Yoshikawa, Akira, Panek, Dalibor, Parkman, Tomas, Bruza, Petr, Mann, Klaus, and Muller, Matthias
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INORGANIC scintillators , *CERIUM compounds , *DOPING agents (Chemistry) , *LUMINESCENCE , *THERMAL stability , *X-ray detection - Abstract
The role and effect of stable Ce^4+ centers in Ce-doped LuAG single crystal scintillator is further studied by means of measurements of several optical, luminescence and scintillation characteristics. Two LuAG:Ce single crystal samples are compared: in one of them the dominating Ce^4 + center is stabilized by high concentration Mg^2+ codoping while the other one shows only the presence of stable Ce^3 + center. Tailored (Eu, Mg)–doped LuAG single crystal is also prepared to test the presence and thermal stability of hole traps in the host which affect the timing characteristics of Ce^4+ scintillation cycle, namely its restoration back to 4+ charge state in last step of the cycle. EPR experiment was also employed at Mg- and (Eu, Mg) doped LuAG samples and the signature of the O^ - hole center stabilized by Mg^2 + ion was clearly obtained. [ABSTRACT FROM AUTHOR]
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- 2016
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5. Luminescence and scintillation properties of Lu3Al5O12 nanoceramics sintered by SPS method.
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Pejchal, Jan, Babin, Vladimir, Beitlerova, Alena, Kucerkova, Romana, Panek, Dalibor, Barta, Jan, Cuba, Vaclav, Yamaji, Akihiro, Kurosawa, Shunsuke, Mihokova, Eva, Ito, Akihiko, Goto, Takashi, Nikl, Martin, and Yoshikawa, Akira
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LUMINESCENCE , *SCINTILLATORS , *LUTETIUM compounds , *NANOSTRUCTURED materials , *SINTERING , *PLASMA gases , *DOPING agents (Chemistry) , *FABRICATION (Manufacturing) - Abstract
Ce-doped lutetium aluminum garnet Lu 3 Al 5 O 12 (LuAG) nanoceramics were fabricated at 1600 °C and 1700 °C by spark-plasma sintering (SPS) method from nano-powders prepared by radiation synthesis. Both undoped and Ce-doped LuAG ceramic samples were also prepared from the nano-powders at 1700 °C with significantly increased pre-heating rate. The backscattered electron images revealed large amount of pores in all the Ce-doped samples causing their significant opacity. On the other hand, very large grains and no pores were revealed in the undoped sample, which was the only transparent one. The radioluminescence measurements revealed superior overall scintillation efficiency of the samples sintered at the temperature 1700 °C, and their defect emission in the UV region was ascribed to oxygen-vacancy-related defects such as F + centers. The photoluminescence decay of the defect emission was characterized by an extremely fast decay time of a few nanoseconds. Influence of sintering procedure and subsequent annealing on the luminescence and scintillation properties is discussed. [ABSTRACT FROM AUTHOR]
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- 2016
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6. Hydrothermally grown ZnO:Mo nanorods exposed to X-ray: Luminescence and charge trapping phenomena.
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Buryi, Maksym, Babin, Vladimir, Artemenko, Anna, Remeš, Zdeněk, Děcká, Kateřina, and Mičová, Júlia
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X-rays , *ELECTRON paramagnetic resonance , *X-ray photoelectron spectroscopy , *ELECTRON paramagnetic resonance spectroscopy , *ELECTRON traps , *RADIOLUMINESCENCE , *LUMINESCENCE , *MOLECULAR beam epitaxy - Abstract
[Display omitted] • Electron and hole trapping centers were observed in the molybdenum doped zinc oxide rods. • Electron trapping centers were mostly molybdenum-based. • Holes were trapped at oxygen complexes. • Exciton- and defect-related emission bands appear suppressed after X-ray irradiation. • Zinc vacancies participated in the charge trapping processes. Peculiarities of the point defects creation under X-ray irradiation and the influence of Mo doping in ZnO powders of nano- and microrods fabricated by the hydrothermal growth method (as-grown and annealed in air) were studied in detail. Correlated experiments of X-ray diffraction, X-ray photoelectron spectroscopy, electron paramagnetic resonance, photo- and radioluminescence as well as thermally stimulated luminescence allowed us to trace the effect of the molybdenum inclusion on the phase purity of synthesized materials and the role of Mo in the creation of X-ray induced point defects. Oxygen-based hole trapping centers (most probably involving interstitial oxygen) as well as Mo5+-based electron trapping centers were observed and their thermal stabilities were studied. Some amount of the hole trapping centers seemed to be directly connected with the creation of Mo5+. Zinc vacancies and the Mo5+ centers up to some extent were assumed to act as recombination centers for the holes released from the hole trapping centers. The X-ray irradiation also affects the luminescence properties of the ZnO:Mo samples – the intensity of the luminescence bands in general becomes weaker. [ABSTRACT FROM AUTHOR]
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- 2022
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7. Charge Transfer and Charge Trapping Processes in Ca- or Al-Co-doped Lu 2 SiO 5 and Lu 2 Si 2 O 7 Scintillators Activated by Pr 3+ or Ce 3+ Ions.
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Laguta, Valentyn, Havlak, Lubomir, Babin, Vladimir, Barta, Jan, Pejchal, Jan, and Nikl, Martin
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CALCIUM ions , *LUTETIUM compounds , *SCINTILLATORS , *ELECTRON paramagnetic resonance , *CRYSTAL defects , *RADIOLUMINESCENCE , *CHARGE transfer , *ION traps , *IONS - Abstract
Lutetium oxyorthosilicate Lu2SiO5 (LSO) and pyrosilicate Lu2Si2O7 (LPS) activated by Ce3+ or Pr3+ are known to be effective and fast scintillation materials for the detection of X-rays and γ-rays. Their performances can be further improved by co-doping with aliovalent ions. Herein, we investigate the Ce3+(Pr3+) → Ce4+(Pr4+) conversion and the formation of lattice defects stimulated by co-doping with Ca2+ and Al3+ in LSO and LPS powders prepared by the solid-state reaction process. The materials were studied by electron paramagnetic resonance (EPR), radioluminescence spectroscopy, and thermally stimulated luminescence (TSL), and scintillation decays were measured. EPR measurements of both LSO:Ce and LPS:Ce showed effective Ce3+ → Ce4+ conversions stimulated by Ca2+ co-doping, while the effect of Al3+ co-doping was less effective. In Pr-doped LSO and LPS, a similar Pr3+ → Pr4+ conversion was not detected by EPR, suggesting that the charge compensation of Al3+ and Ca2+ ions is realized via other impurities and/or lattice defects. X-ray irradiation of LPS creates hole centers attributed to a hole trapped in an oxygen ion in the neighborhood of Al3+ and Ca2+. These hole centers contribute to an intense TSL glow peak at 450–470 K. In contrast to LPS, only weak TSL peaks are detected in LSO and no hole centers are visible via EPR. The scintillation decay curves of both LSO and LPS show a bi-exponential decay with fast and slow component decay times of 10–13 ns and 30–36 ns, respectively. The decay time of the fast component shows a small (6–8%) decrease due to co-doping. [ABSTRACT FROM AUTHOR]
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- 2023
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8. Luminescence and ESR Study of Irregular Ce3+ Ions in LuAG:Ce Single Crystals.
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Babin, Vladimir, Laguta, Valentin V., Makhov, Aleksei, Nejezchleb, Karel, Nikl, Martin, and Zazubovich, Svetlana
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QUANTUM perturbations , *QUANTUM theory , *IONS , *LUMINESCENCE , *ELECTRONS , *ALUMINUM - Abstract
Luminescence of new irregular Ce3+-related centers: the unperturbed and perturbed Ce3+ ions located in Al3+ sites and the CeLu3+ ions perturbed by LuAl3+ ions was found. The systematic stuffy of these centers by means of the ESR and luminescence methods and their influence on scintillation characteristics was performed. The structure and symmetry of the irregular Ce3+ centers was established and their spectral characteristics were explained. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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9. The role of <f>Pb2+</f> as a sensitizer for <f>Gd3+</f>–<f>Eu3+</f> downconversion couple in fluorides
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Babin, Vladimir, D. Oskam, Koert, Vergeer, Peter, and Meijerink, Andries
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LEAD , *FLUORIDES , *QUANTUM chemistry , *TEMPERATURE - Abstract
Spectroscopic properties of
Pb2+ in different fluoride host lattices were studied in order to investigate ifPb2+ can serve as a sensitizer for theGd3+ –Eu3+ quantum cutting system. StrongB′ emission ofPb2+ was found in several fluoride host lattices and for the first timeB′ emission is reported at room temperature. It is shown that sensitization of the6G levels ofGd3+ is possible viaB′ emission ofPb2+ in the host lattice(BaF2)0.6(GdF3)0.4 and visible quantum cutting with an efficiency of 20% is observed upon excitation in the C band ofPb2+ . The possibility of sensitization ofGd3+ byA′ emission ofPb2+ inKMgF3 is discussed. [Copyright &y& Elsevier]- Published
- 2004
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10. First investigation of the morphological and luminescence properties of HfO2 nanoparticles synthesized by photochemical synthesis.
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Villa, Irene, Procházková, Lenka Prouzová, Mihóková, Eva, Babin, Vladimir, Král, Robert, Zemenová, Petra, Falvey, Alexandra, Čuba, Václav, Salomoni, Matteo, Pagano, Fiammetta, Calà, Roberto, Frank, Isabel, Auffray, Etiennette, and Nikl, M.
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SCINTILLATORS , *LUMINESCENCE , *NANOPARTICLE size , *NANOPARTICLES , *RADIOLUMINESCENCE , *INDUSTRIAL costs - Abstract
For the first time, hafnia (HfO2) nanoparticles have been produced by photochemical synthesis. The photochemical route has been proven to be scalable, affordable, and straightforward to create monoclinic HfO2 nanoparticles with a size of tens of nanometers. The exploitation of this route offers a chance to create large amounts of dense nanoparticles with reduced costs and time of production for future creation of large area composite scintillators for fast timing techniques. Specific annealing treatments from 450 °C to 1000 °C have been targeted to tune the structural and morphological properties and optimize the luminescence of the nanoparticles. Hafnia nanoparticles annealed at low temperature display an amorphous structure. After thermal treatment at 1000 °C, HfO2 nanoparticles crystallize into a monoclinic phase, as evidenced by thermal analyses and X-ray diffraction. Radioluminescence and photoluminescence of HfO2 have been investigated at room temperature and 77 K. The emission band of hafnia covers a range from 300 to 600 nm and it can be attributed to defects within the matrix. In particular, the highest radioluminescence intensity appears in the crystalline sample annealed at 1000 °C, thanks to the higher crystallinity degree and the reduction of non-radiative channels and quenching defects. Photoluminescence and scintillation decay have evidenced the presence of the fast decay in the nanosecond time range. Thus, due to their size, density, and spectroscopic and timing features, monoclinic hafnia nanoparticles obtained by photochemical synthesis are attractive for potential creation of large area scintillating composites. [ABSTRACT FROM AUTHOR]
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- 2023
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11. Luminescence and scintillation properties of Mg-codoped LuAG:Pr single crystals annealed in air.
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Jan Pejchal, null, Buryi, Maksym, Babin, Vladimir, Prusa, Petr, Beitlerova, Alena, Jan Barta, null, Havlak, Lubomir, Kamada, Kei, Yoshikawa, Akira, Laguta, Valentin, and Nikl, Martin
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LUMINESCENCE , *MAGNESIUM , *LUTETIUM compounds , *DOPING agents (Chemistry) , *PRASEODYMIUM , *ANNEALING of crystals - Abstract
The influence of the Mg 2+ codoping and annealing in the air on the scintillation and luminescence characteristics of Pr-doped lutetium-aluminum garnet crystals (LuAG) was studied to find a possible positive effect of Pr 4+ . The overall scintillation efficiency under X-ray excitation of the annealed Pr- doped samples decreased with increasing Mg concentration. This was explained by increased overlap of the Pr 3+ 5d-4f emission with the charge-transfer (CT) absorption band of the Pr 4+ ion stabilized by Mg 2+ . This absorption caused even greater decrease of the light yield, as the light is collected from the whole sample volume in the pulse-height spectrum measurement. Electron centers based on oxygen vacancies (F + centers) which can have negative influence on scintillation mechanism were revealed by the electron paramagnetic resonance (EPR) experiments. The O - hole center was detected as well and the temperature dependences of the EPR spectra showed that its thermal stability was decreased by Mg codoping. Negligible changes in the decay time of Pr 3+ 5d-4f photoluminescence exclude the non-radiative energy transfer from relaxed 5d 1 excited state of Pr 3+ towards CT absorption transition of Pr 4+ and suggest that simple reabsorption of the emitted light takes place. Unlike for the Ce-doped analogs, promoting the Pr 3+ luminescence center to the tetravalent state by divalent ion co-doping and air annealing did not improve scintillation properties of Pr-doped LuAG. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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12. Insights into luminescence and energy transfer processes in Ce3+- and Tb3+ co-doped (Gd, Y)3Al2Ga3O12 garnet single crystals.
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Omuro, Kazuya, Yoshino, Masao, Bartosiewicz, Karol, Horiai, Takahiko, Murakami, Rikito, Kim, Kyoung Jin, Kamada, Kei, Kucerkova, Romana, Babin, Vladimir, Nikl, Martin, Yamaji, Akihiro, Hanada, Takashi, Yokota, Yuui, Kurosawa, Shunsuke, Ohashi, Yuji, Sato, Hiroki, and Yoshikawa, Akira
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ENERGY transfer , *SINGLE crystals , *DOPING agents (Chemistry) , *LUMINESCENCE , *GARNET , *X-ray imaging - Abstract
Driven by the pursuit of optimizing the luminescent properties of garnet-based single crystals for X-ray imaging applications, this work reports on the successful synthesis and in-depth characterization of GYAGG crystals doped with Ce³⁺ or Tb³⁺ ions, and doubly-doped with both of them. Micro-pulling down synthesis yielded crystals with a single cubic phase confirmed by X-ray diffraction. Photoluminescence (PL) and radioluminescence (RL) measurements on Ce³⁺,Tb³⁺ co-doped GYAGG revealed bidirectional energy transfer processes. Characteristic broadband 5d 1 →4f emission of Ce³⁺ centers peaking at 530 nm and narrow 4f→4f emission lines of Tb³⁺ ions starting from 5D 4 level within 480–630 nm were observed. At higher doping levels, cross-relaxation in Tb³⁺ pairs resulted depleted 5D 3 state and only the emission from 5D 4 one was observed in the spectra. Analysis of PL decay characteristics corroborated the spectral observations, confirming progressively decreasing Ce³⁺ decay time (down to 40 ns at 15 % Tb3+) due to enhanced Ce³⁺→Tb³⁺ energy transfer. Similarly, the Tb³⁺ decay time accelerated by more than 60 % after the Ce³⁺ co-doping. Notably, co-doping with 0.5 % Ce³⁺ and 10–15 % Tb³⁺ doubled the luminescence intensity of RL spectra compared to 0.5 % Ce³⁺-doping alone, attributed to the increased density of emitting centers. • High-quality and crack-free GYAGG:Ce,Tb single crystals were successfully grown. • The photoluminescence spectra revealed Ce³⁺↔Tb³⁺ bidirectional energy transfer. • At lower Tb³⁺ doping (0.5 %), the bidirectional energy transfer was inefficient. • High Tb³⁺ doping (15 %) significantly enhanced energy transfer. • Co-doping yielded a two-fold radioluminescence intensity compared to sole doping. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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13. The Effect of Be Co‐Doping on Luminescence Properties of Gd3Al3Ga2O12:Ce Glass Ceramics.
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Tratsiak, Yauhen, Trusova, Ekateryna, Buryi, Maksym, Babin, Vladimir, Dominec, Filip, Hájek, František, and Malashkevich, Georgii
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LUMINESCENCE , *GADOLINIUM , *CERAMICS , *RADIOLUMINESCENCE , *GLASS , *ELECTRON traps - Abstract
The glass‐ceramics (GC) of gadolinium aluminum gallium garnets with the expected composition of Gd3Al3Ga2O12:Ce and Gd3Al3Ga2O12:Ce,Be (GAGG:Ce and GAGG:Ce,Be, respectively) are fabricated by crystallization from the Gd2O3–Al2O3–Ga2O3–CeO2–SiO2–BeO (Gd:Ga:Al ratio is close to 3:2:3) glasses. The influence of Be2+ co‐doping (including doping level) on the luminescent properties of the GAGG is demonstrated. In particular, Be co‐doping results in the suppression of the Ce3+‐related radioluminescence (RL) and as a consequence, the light yield is lowered as well. The conclusion is made that Be2+ creates effective electron or hole trapping centers. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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14. Luminescence properties and scintillation response in Ce3+-doped Y2Gd1Al5-xGaxO12(x = 2, 3, 4) single crystals.
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Chewpraditkul, Warut, Pánek, Dalibor, Brůža,, Petr, Chewpraditkul, Weerapong, Wanarak, Chalerm, Pattanaboonmee, Nakarin, Babin, Vladimir, Bartosiewicz, Karol, Kamada, Kei, Yoshikawa, Akira, and Nikl, Martin
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LUMINESCENCE , *SCINTILLATION counters , *CRYSTALS , *EXCITATION (Physiology) , *TEMPORAL bone - Abstract
The compositional dependence of luminescence properties and scintillation response were investigated in Ce3+-doped Y2Gd1Al5-xGaxO12 (x=2, 3, 4) single crystals. The Gd3+ → Ce3+ energy transfer was evidenced by photoluminescence excitation spectra of Ce3+ emission. With increasing Ga content in the garnet host, the Ce3+ luminescence from the lowest 5d level (5d1) is shifted toward higher energy due to the decrease in the crystal field splitting of the 5d levels. Light yield (LY) and its dependence on the amplifier shaping time were measured under excitation with γ-rays High LY value of ~38 000 ph/MeV was obtained for a Y2Gd1Al5-xGaxO12:Ce sample. Scintillation decay was measured with an extended dynamical and temporal scale under the nanosecond pulse soft X-ray excitation. The decrease of both LY value and relative contribution of slower decay component in the scintillation response was observed with increasing Ga content in the garnet host. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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15. Light Yield and Timing Characteristics of Lu₀.₈Gd₂.₂(Al5–xGax)O₁₂:Ce,Mg Single Crystals.
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Sakthong, Ongsa, Chewpraditkul, Warut, Pattanaboonmee, Nakarin, Chewpraditkul, Weerapong, Yamaji, Akihiro, Kamada, Kei, Kurosawa, Shunsuke, Yoshikawa, Akira, Witkowski, Marcin, Drozdowski, Winicjusz, Szczesniak, Tomaz, Moszynski, Marek, Babin, Vladimir, and Nikl, Martin
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SINGLE crystals , *RADIOLUMINESCENCE , *PHOTONS , *LUMINESCENCE , *LOW temperatures , *SCINTILLATORS - Abstract
The scintillation characteristics of Lu0.8Gd2.2 (Al5–xGax)O12:Ce,Mg (x = 2.6 and 3) single crystals grown by the micropulling down method are investigated. The light yield of 27600 photons/MeV obtained for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg is higher than that of 25 400 photons/MeV obtained for Lu0.8Gd2.2Al2.4Ga2.6O12:Ce,Mg. The photoluminescence and scintillation decays measured at room temperature (RT) for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg are faster than those for Lu0.8Gd2.2Al2.4Ga2.6O12:Ce,Mg. Temperature dependence of radioluminescence (RL) intensity indicates a lower quenching temperature for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg. Coincidence time resolution of a Lu0.8Gd2.2Al2Ga3O12:Ce,Mg detector in coincidence experiment with a BaF2 detector was measured to be 410 ps. The afterglow and thermally stimulated luminescence (TSL) characteristics below RT are also measured. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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16. Temperature dependence of photo- and radio-luminescence and scintillation properties of Lu2YAl2.5Ga2.5O12:Ce,Mg multicomponent garnet crystals.
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Chewpraditkul, Warut, Horiai, Takahiko, Beitlerova, Alena, Kucerkova, Romana, Babin, Vladimir, Yoshikawa, Akira, Chewpraditkul, Weerapong, and Nikl, Martin
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GARNET , *SCINTILLATORS , *LUMINESCENCE quenching , *CRYSTALS , *RADIOLUMINESCENCE , *THERMOLUMINESCENCE , *LUMINESCENCE - Abstract
Luminescence and scintillation properties of Lu 2 YAl 2.5 Ga 2.5 O 12 :Ce,Mg (0.02, 0.05 %) garnet crystals grown by the micro-pulling down method were investigated. The onset temperature for luminescence quenching at ∼365 K is determined from the temperature dependence of photoluminescence decay time. At room temperature, the Mg (0.05 %) sample exhibits high integral scintillation efficiency of ∼445 % of BGO crystal, light yield value of 23,500 photons/MeV, and fast scintillation decay times of 20 ns (15 %) + 54 ns (85 %). The higher radioluminescence intensity of the Mg (0.05 %) sample correlates with an appearance of its lower themally-stimulated luminescence intensity in 77–500 K range. • Luminescence and scintillation properties of Lu 2 YAl 2.5 Ga 2.5 O 12 :Ce,Mg (Mg = 0.02 %, 0.05 %) crystals are investigated. • Both crystals show onset of luminescence quenching at 365 K. • Lu 2 YAl 2.5 Ga 2.5 O 12 :Ce,0.05%Mg shows light yield of 23,500 photons/MeV. • Lu 2 YAl 2.5 Ga 2.5 O 12 :Ce,0.05%Mg shows scintillation decay time of 20 ns (14 %) + 54 ns (86 %). • Thermoluminescence characteristics are investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Scintillation properties of Gd3Al2Ga3O12:Ce, Li and Gd3Al2Ga3O12:Ce, Mg single crystal scintillators: A comparative study.
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Chewpraditkul, Warut, Pattanaboonmee, Nakarin, Sakthong, Ongsa, Wantong, Kriangkrai, Chewpraditkul, Weerapong, Yoshikawa, Akira, Kamada, Kei, Kurosawa, Shunsuke, Szczesniak, Tomasz, Moszynski, Marek, Babin, Vladimir, and Nikl, Martin
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SINGLE crystals , *SCINTILLATORS , *LUMINESCENCE quenching , *RADIOLUMINESCENCE , *PHOTONS , *LUMINESCENCE - Abstract
The scintillation characteristics of Gd 3 Al 2 Ga 3 O 12 :Ce, Li (GAGG:Ce,Li) and Gd 3 Al 2 Ga 3 O 12 :Ce, Mg (GAGG:Ce,Mg) single crystals were compared. Radioluminescence spectra and photoluminescence decay curves were measured at various temperatures between 77 and 500 K to investigate the thermal luminescence quenching. At 662 keV γ rays, the LY value of 35,400 photons/MeV and energy resolution of 6.9% obtained for GAGG:Ce, Li are superior to those of 24,200 photons/MeV and 9.5% for GAGG:Ce,Mg. Scintillation decays are approximated by a double exponentials with a fast principal decay component of 47 ns (83%) for GAGG:Ce, Mg and 90 ns (86%) for GAGG:Ce,Li. Coincidence time resolution of 282 ps obtained for GAGG:Ce, Mg is better than that of 389 ps for GAGG:Ce,Li. GAGG:Ce, Mg shows a much lower afterglow and thermally stimulated luminescence intensity with respect to GAGG:Ce,Li. • Scintillation properties of Li+ and Mg2+ -codoped Gd 3 Al 2 Ga 3 O 12 :Ce are compared. • Gd 3 Al 2 Ga 3 O 12 :Ce, Mg exhibits better timing performance. • Gd 3 Al 2 Ga 3 O 12 :Ce, Mg shows lower afterglow and TSL intensity. • Gd 3 Al 2 Ga 3 O 12 :Ce, Li exhibits high light yield and good energy resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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18. Luminescence, scintillation, and energy transfer in SiO2-Al2O3-B2O3-Gd2O3:Ce3+,Pr3+ glasses.
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Lertloypanyachai, Prapon, Chewpraditkul, Weerapong, Pattanaboonmee, Nakarin, Chen, Danping, Babin, Vladimir, Beitlerova, Alena, and Nikl, Martin
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LUMINESCENCE , *SCINTILLATORS , *ENERGY transfer , *SILICA , *ALUMINUM compounds , *CERIUM compounds , *METALLIC glasses - Abstract
Ce3+,Pr3+-codoped SiO2-Al2O3-B2O3-Gd2O3 glasses (SABG:Ce,Pr) were prepared by melt quenching under a CO reducing atmosphere. Luminescence properties were investigated under UV and X-ray excitations. A dominant emission band at 430 nm belonging to the Ce3+:5d1 → 4f transition was observed in the photo- and radio-luminescence spectra. The energy transfer occurs from this Ce3+ band toward the 3PJ levels of Pr3+ with an efficiency of up to 24%, followed by the reduction of integrated luminescence intensity with an increasing Pr3+ concentration. This result is attributed to the increase in the reabsorption of Ce3+ luminescence and the non-radiative energy transfer toward the 3PJ levels of Pr3+. The cross-relaxation process within the Pr3+ pairs can further diminish the total luminescence yield at high Pr3+ concentrations. The integral scintillation efficiency and light yield measurements were carried out and compared to the reference Bi4Ge3O12 (BGO) crystal. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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19. Synthesis of the cerium doped Gd3Al3Ga2O12-based glass nanoceramics: Luminescence and optical absorption properties.
- Author
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Buryi, Maksym, Tratsiak, Yauhen, Trusova, Ekateryna, Babin, Vladimir, Paterek, Juraj, Kučerková, Romana, Remeš, Zdeněk, Hájek, František, Landová, Lucie, Drahokoupil, Jan, and Chertopalov, Sergii
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GLASS-ceramics , *LIGHT absorption , *OPTICAL properties , *TRANSPARENT ceramics , *ENERGY dispersive X-ray spectroscopy , *CERIUM , *LUMINESCENCE spectroscopy , *LUMINESCENCE - Abstract
Cerium doped gadolinium gallium aluminum garnet (Gd 3 Al 3 Ga 2 O 12 , GAGG) was synthesized in the glass ceramics form by the crystallization from Gd 2 O 3 –Al 2 O 3 –Ga 2 O 3 –SiO 2 –CeO 2 glass in the following weight proportion: 101 : 26: 47 : 25: 1. The spatial distribution and incorporation of Ce into the GAGG ceramic grains as well as the luminescence and scintillation performance are studied carrying out correlated experiments of photo-, radio- and cathodoluminescence including decay kinetics as well as energy dispersive X-ray spectroscopy combined with scanning electron microscopy. Optical absorption features were investigated using photothermal deflection spectroscopy. Cerium stays within the material mostly in the Ce3+ charge state. Its distribution in the bulk of the sample exhibits irregular trend indicating the tendency to coalesce in the middle. • The GAGG:Ce glass nanoceramics was fabricated. • Spatial distribution of Ce3+ in the batch of the glass nanoceramics was observed. • Hole trapping processes affect the luminescence in GAGG:Ce glass nanoceramics. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
20. Optical and scintillation properties of Ce3+-doped YGd2Al5−xGaxO12 (x=2,3,4) single crystal scintillators.
- Author
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Chewpraditkul, Warut, Brůža, Petr, Pánek, Dalibor, Pattanaboonmee, Nakarin, Wantong, Kriangkrai, Chewpraditkul, Weerapong, Babin, Vladimir, Bartosiewicz, Karol, Kamada, Kei, Yoshikawa, Akira, and Nikl, Martin
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SCINTILLATORS , *LUMINESCENCE , *SINGLE crystals , *IONIZATION (Atomic physics) , *PARTICLE detectors - Abstract
The optical and scintillation properties of Ce 3+ -doped YGd 2 Al 5− x Ga x O 12 ( x =2,3,4) single crystals were investigated. With increasing Ga content in the garnet host, the 5d 1 absorption and emission bands shift toward higher energy due to the decrease in the crystal field splitting of the 5d levels. Temperature dependences of absorption and emission spectra and of photoluminescence decays of both prompt and delayed components were measured. Light yield (LY) and its dependence on an amplifier shaping time were measured under excitation with γ-rays. High LY value of 38,000 photons/MeV was obtained for a YGd 2 Al 2 Ga 3 O 12 :Ce sample. Scintillation decay was measured with an extended dynamical and temporal scale under the nanosecond-pulsed soft X-ray excitation. The relative content of the fastest component in the scintillation response increases with increasing Ga content. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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- View/download PDF
21. Temperature dependence of radio- and photoluminescence and scintillation properties of Y0.6Gd2.4Al2Ga3O12:Ce,Mg single crystal.
- Author
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Chewpraditkul, Warut, Pattanaboonmee, Nakarin, Chewpraditkul, Weerapong, Kim, Kyoung Jin, Yoshikawa, Akira, Kamada, Kei, Kurosawa, Shunzuke, Beitlerova, Alena, Kucerkova, Romana, Babin, Vladimir, and Nikl, Martin
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CESIUM , *SCINTILLATORS , *SINGLE crystals , *PHOTOLUMINESCENCE , *THERMOLUMINESCENCE , *RADIOLUMINESCENCE , *LUMINESCENCE quenching , *LUMINESCENCE - Abstract
Mg2+-codoped Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce (YGAGG:Ce,Mg) single crystal was grown by the Czochralski method and its luminescence and scintillation properties were investigated. Temperature dependence of radioluminescence (RL) yield and photoluminescence (PL) decay time was measured, and activation energy of thermal ionization process was determined from temperature-dependent PL decay time measurement. YGAGG:Ce,Mg exhibited high X-ray excited RL yield almost 5 times higher than BGO reference scintillator. Its light yield of 41,500 ph/MeV and scintillation decay times of 12 ns (2%) + 52 ns (65%) + 207 ns (33%) were measured under excitation with 662 keV γ rays from 137Cs source. Afterglow and thermally stimulated luminescence characteristics are also investigated. • Luminescence and scintillation properties of Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce,Mg crystal are investigated. • Temperature dependence of photo-and radioluminescence are presented. • Y 0.6 Gd 2.4 Al 2 Ga 3 O 12 :Ce,Mg shows high light yield of 41,500 photons/MeV. • Luminescence quenching above RT can be caused by thermal ionization. • Afterglow and thermoluminescence characteristics are investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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22. Luminescence Mechanism in Doubly Doped LaF3:Er,Nd VUV Scintillator.
- Author
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Pejchal, Jan, Nikl, Martin, Fukuda, Kentaro, Kawaguchi, Noriaki, Yanagida, Takayuki, Yokota, Yuui, Yoshikawa, Akira, and Babin, Vladimir
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LUMINESCENCE , *LANTHANUM , *FAR ultraviolet radiation , *SCINTILLATORS , *ENERGY transfer , *FLUORIDES - Abstract
Doubly doped LaF3:Er, Nd scintillation crystals were grown by modified micropulling-down method. The Er codoping was chosen to enhance the energy transfer from the host lattice to the Nd3+ luminescence center via the 5d-levels of Er3+, which can be enabled by the overlap of Er3+ 5d-4f emission spectrum with the Nd3+ 4f-5d absorption. However, no relevant energy transfer was found by photo- and radioluminescence spectra measurements. The reasons of no significant positive effect of Er codoping are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
23. Study of VUV emission and γ-ray responses of Nd:BaF2 scintillaotor
- Author
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Yanagida, Takayuki, Kawaguchi, Noriaki, Yokota, Yuui, Ishidu, Sumito, Fukuda, Kentaro, Yoshikawa, Akira, Pejchal, Jan, Nikl, Martin, Babin, Vladimir, Sekiya, Hiroyuki, and Kamada, Kei
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SCINTILLATORS , *GAMMA rays , *METAL crystal growth , *LUMINESCENCE , *NEODYMIUM , *SYNCHROTRON radiation - Abstract
Abstract: Nd3+ 1%, 5% and 10% doped BaF2 single crystals were grown by the micro-pulling down method. Photoluminescence properties, including excitation and emission spectra and luminescence decay were measured under synchrotron radiation excitation at the Superlumi station in HASYLAB at DESY (Hamburg, Germany). The Nd3+ related 5d-4f emission lines peaking around 180 nm, 230 nm, and 260 nm, identified as the 5d–4Ij, 5d–4Fj, and 5d–2Gj transitions, were observed under 140–168 nm excitation. In photoluminescence decay under the 160 nm excitation, the dominant component decay time is about 12, 2.5 and 1.2 ns for Nd3+ 1%, 5% and 10% concentration, respectively. The decay time shortening is explained by the concentration quenching effect. Transmittance of Nd1% sample is about 80% for wavelengths above 185 nm. Finally, gamma-ray responses, non-proportionality and energy resolution of Nd1% sample were compared with the undoped BaF2 scintillator. The light yield of the Nd1%:BaF2 is about 93% of that of undoped BaF2. ©2009 Elsevier Ltd. All rights reserved. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
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24. Scintillation characteristics and temperature quenching of radio- and photoluminescence of Mg2+-codoped (Lu,Gd)3Al2.4Ga2.6O12:Ce garnet crystals.
- Author
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Chewpraditkul, Warut, Pattanaboonmee, Nakarin, Sakthong, Ongsa, Chewpraditkul, Weerapong, Yamaji, Akihiro, Kurosawa, Shunsuke, Kamada, Kei, Yoshikawa, Akira, Makowski, Michał, Witkowski, Marcin E., Drozdowski, Winicjusz, Beitlerova, Alena, Kucerkova, Romana, Babin, Vladimir, and Nikl, Martin
- Subjects
- *
DEBYE temperatures , *PHOTOLUMINESCENCE , *GARNET , *RADIOLUMINESCENCE , *LUMINESCENCE quenching , *ELECTRON traps , *YTTRIUM aluminum garnet - Abstract
Luminescence and scintillation characteristics of Mg2+-codoped (Lu x Gd 3-x)Al 2.4 Ga 2.6 O 12 :Ce (x = 0.2–0.8) garnet crystals grown by the micro-pulling down method are investigated. The Ce3+ 5d 1 → 4f luminescence is blue-shifted with increasing Lu content due to the decrease in crystal field splitting of the 5 d levels. With increasing Lu content, the shortening of scintillation decay time accompanied with a decrease of LY value as measured at room temperature can be explained by thermal ionization of the Ce3+ 5d 1 excited state. Co-doping with Mg2+ results in the shortening of scintillation decay time, the reduction of LY value and afterglow intensity. At low temperature the radioluminescence quenching is observed in correlation with large thermoluminescence peaks, which can be attributed to the localization of electrons at intrinsic shallow traps. • Luminescence and scintillation of (Lu,Gd) 3 Al 2.4 Ga 2.6 O 12 :Ce, Mg crystals are investigated. • Temperature dependence of photo-and radioluminescence are presented. • Luminescence quenching above RT can be caused by thermal ionization. • Afterglow and low-temperature TL characteristics are investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
25. On the Role of Cs 4 PbBr 6 Phase in the Luminescence Performance of Bright CsPbBr 3 Nanocrystals.
- Author
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Děcká, Kateřina, Suchá, Adéla, Král, Jan, Jakubec, Ivo, Nikl, Martin, Jarý, Vítězslav, Babin, Vladimir, Mihóková, Eva, and Čuba, Václav
- Subjects
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NANOCRYSTALS , *LUMINESCENCE , *RADIOLUMINESCENCE , *ENERGY transfer , *SCINTILLATION counters - Abstract
CsPbBr3 nanocrystals have been identified as a highly promising material for various optoelectronic applications. However, they tend to coexist with Cs4PbBr6 phase when the reaction conditions are not controlled carefully. It is therefore imperative to understand how the presence of this phase affects the luminescence performance of CsPbBr3 nanocrystals. We synthesized a mixed CsPbBr3-Cs4PbBr6 sample, and compared its photo- and radioluminescence properties, including timing characteristics, to the performance of pure CsPbBr3 nanocrystals. The possibility of energy transfer between the two phases was also explored. We demonstrated that the presence of Cs4PbBr6 causes significant drop in radioluminescence intensity of CsPbBr3 nanocrystals, which can limit possible future applications of Cs4PbBr6-CsPbBr3 mixtures or composites as scintillation detectors. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
26. Doubly doped BaY2F8:Er,Nd VUV scintillator
- Author
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Pejchal, Jan, Nikl, Martin, Fukuda, Kentaro, Kawaguchi, Noriaki, Yanagida, Takayuki, Yokota, Yuui, Yoshikawa, Akira, and Babin, Vladimir
- Subjects
- *
SCINTILLATORS , *RARE earth fluorides , *LUMINESCENCE , *ENERGY transfer , *PHOTON emission , *ELECTRONIC excitation - Abstract
Abstract: Doubly doped BaY2F8:Er,Nd scintillation crystals were grown by modified micro-pulling-down method. The Er co-doping was chosen to enhance the energy transfer from the host lattice to the Nd3+ luminescence center via the 5d-levels of Er3+, which can be enabled by the overlap of Er3+ 5d-4f emission spectrum with the Nd3+ 4f-5d absorption. The energy transfer was clearly evidenced in the BaY2F8:Er,Nd. The processes are complicated by energy migration to killer centres and/or cross-relaxation processes. The luminescence and energy transfer mechanism are discussed. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
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