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2. Crystal growth and optical properties of Ce-doped (La,Y)$_2$Si$_2$O$_7$ single crystal

Author

Horiai, Takahiko, Paterek, Juraj, Pejchal, Jan, Jarosova, Marketa, Rohlicek, Jan, Kurosawa, Shunsuke, Hanada, Takashi, Yoshino, Masao, Yamaji, Akihiro, Toyoda, Satoshi, Sato, Hiroki, Ohashi, Yuji, Kamada, Kei, Yokota, Yuui, Yoshikawa, Akira, and Nikl, Martin

Subjects
Physics - Optics, Condensed Matter - Materials Science
Abstract

We have grown Ce-doped (La,Y)$_2$Si$_2$O$_7$ single crystal by micro-pulling-down method and investigated its optical and scintillation properties. We have successfully prepared the single crystal with (Ce$_{0.015}$La$_{0.600}$Y$_{0.385}$)$_2$Si$_2$O$_7$ composition. The observed thermal quenching process could be characterized by the quenching temperature (T50%) of 526 K and its activation energy was determined to be 0.62 eV. Further considering the thermal quenching factors, it was found that the thermal quenching was caused by at least the thermal ionization and maybe also by classical thermal quenching. The light output and scintillation decay time were evaluated to be ~12,000 photons/MeV and ~42 ns, respectively. These results indicate that (Ce$_{0.015}$La$_{0.600}$Y$_{0.385}$)$_2$Si$_2$O$_7$ has a great potential for application in scintillation materials.

Published
2021
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11. Two- and Three-Layered Composite Scintillators Based on the Ce3+-Doped GAGG and TbAG Garnets for the Simultaneous Registration of Various Types of Ionizing Radiation

Author

Syrotych, Yurii, Gorbenko, Vitaliy, Pejchal, Jan, Kucerkova, Romana, Mares, Jiri, Nikl, Martin, Kamada, Kei, Yoshikawa, Akira, Fedorov, Alexander, Sidleskiy, Oleg, Winiecki, Janusz, and Zorenko, Yuriy

Abstract

This work presents our most recent results in the development of composite scintillators using the liquid phase epitaxy growth method based on the single crystalline films and single crystals of garnet compounds for the radiation monitoring of different components of mixed ionization radiation fluxes. Such composite scintillators present two- and three-layered epitaxial structures consisting of two single crystalline films of Ce3+-doped garnets, namely, Gd3Al5–xGaxO12:Ce garnet with a Ga content of x= 1.75–2.25 as a first film layer and Tb3Al5O12:Ce garnet as a second film layer. As substrates, Gd3Al5–xGaxO12:Ce single crystals with fixed Ga concentrations x= 2.3, 2.5, and 3.0 were used. For the estimation of scintillation properties of the respective epitaxial structures (pulse height spectra, light yield, and scintillation decay kinetics), we have used three types of ionizing radiation: α-particles (239Pu), β-particles (90Sr + 90Y), and γ-quanta (137Cs).

Published
2024
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12. Three-Layered Composite Scintillator Based on the Epitaxial Structures of YAG and LuAG Garnets Doped with Ce 3+ and Sc 3+ Impurities.

Author

Witkiewicz-Łukaszek, Sandra, Gorbenko, Vitalii, Zorenko, Tetiana, Pejchal, Jan, Mares, Jiri A., Kucerkova, Romana, Beitlerova, Alena, Nikl, Martin, Sidletskiy, Oleg, Winiecki, Janusz, D'Ambrosio, Carmelo, and Zorenko, Yuriy

Subjects
LIQUID phase epitaxy, LIQUID crystal films, IONIZING radiation, SINGLE crystals, SUBSTRATES (Materials science), SCINTILLATORS
Abstract

In this study, we propose novel three-layer composite scintillators designed for the simultaneous detection of different ionizing radiation components. These scintillators are based on epitaxial structures of LuAG and YAG garnets, doped with Ce3+ and Sc3+ ions. Samples of these composite scintillators, containing YAG:Ce and LuAG:Ce single crystalline films with different thicknesses and LuAG:Sc single crystal substrates, were grown using the liquid phase epitaxy method from melt solutions based on PbO-B2O3 fluxes. The scintillation properties of the proposed composites, YAG:Ce film/LuAG:Sc film/LuAG:Ce crystal and YAG:Ce film/LuAG:Ce film/LuAG:Sc crystal, were investigated under excitation by radiation with α-particles from a 239Pu source, β-particles from 90Sr sources and γ-rays from a 137Cs source. Considering the properties of the mentioned composite scintillators, special attention was paid to the ability of simultaneous separation of the different components of mixed ionizing radiation containing the mentioned particles and quanta using scintillation decay kinetics. The differences in scintillation decay curves under α- and β-particle and γ-ray excitations were characterized using figure of merit (FOM) values at various scintillation decay intensity levels (1/e, 0.1, 0.05, 0.01). [ABSTRACT FROM AUTHOR]

Published
2024
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23. Development of a micro ORC power unit using digital prototyping methods

Author

Pejchal Jan and Kolář Petr

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

The development of the prototype of the ORC micro turbine includes already in the design phase the creation of a digital prototype based on the use of computational simulations, especially the CFD flow program Simcenter STAR CCM +, strength and rotor-dynamic FEA analyses of system behaviour Simcenter 3D. This is followed by the optimization of the device by increasing its efficiency and improving the mechanical properties of the system. For this purpose, we used the optimization program HEEDS and the topological optimization method Simcenter 3D. This was followed by the production of a prototype, where 3D printing technology was used to produce turbine housing moulds and other components. A huge attention of this contribution is devoted to these additive production processes.

Published
2022
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48. Towards persistent phosphors deliberate design: study of La-Ga admixing in LuAG:Ce crystals to engineer elemental homogeneity and carriers trap depths

Author

Bartosiewicz, Karol, primary, Fritz, Verena, additional, Van der Heggen, David, additional, Szymanski, Damian, additional, Zeler, Justyna, additional, Yamaji, Akihiro, additional, Pejchal, Jan, additional, Kucerkova, Romana, additional, Beitlerová, Alena, additional, Kurosawa, Shunsuke, additional, Yoshikawa, Akira, additional, Smet, Philippe F, additional, Zych, Eugeniusz, additional, and Nikl, Martin, additional

Published
2023
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