| 1. |
- Pejchal, Jan, et al.
(author)
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Untangling the controversy on Ce3+luminescence in LaAlO3crystals
- 2022
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In: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 3:8, s. 3500-3512
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Journal article (peer-reviewed)abstract
- Aluminum perovskites represent an important group of promising scintillation materials with excellent proportionality and energy resolution, but due to difficulties in crystal growth not much attention has been paid to them. We studied a Ce-doped LaAlO3lanthanum-aluminum perovskite (LaAP) because of its easy crystal growth facilitated by the large La3+cations in the matrix. Moreover, recent observations of intense blue luminescence by some researchers show that the potential of this material could not be ruled out. On the other hand, some reports claim that Ce3+luminescence is completely absent in the LaAP matrix. Therefore, we have decided to study this material in much greater detail using an extended set of correlated experiments to explain the observed discrepancies and underlying phenomena. Crystal growth by the micro-pulling-down method is reported together with the luminescence and scintillation properties. We demonstrate the influence of inclusions of other aluminate phases created during the crystal growth on the luminescence processes. The existence of the phases was simultaneously confirmed by observations using a scanning electron microscope, cathodoluminescence, energy-dispersive X-ray analysis and electron paramagnetic resonance (EPR), which were correlated with photoluminescence and scintillation studies. The EPR evidenced the incorporation of Ce ions in different environments comprising the LaAP matrix and inclusions. Based on these results, the luminescence mechanism is proposed and discussed and the low scintillation efficiency of the Ce-doped LaAP is explained together with the discrepancies in the literature.
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| 2. |
- Garmysheva, Tatiana, et al.
(author)
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Luminescence of ODC(II) in quartz and cristobalite glasses
- 2022
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In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093. ; 575
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Journal article (peer-reviewed)abstract
- The results of the optical spectroscopy of twofold coordinated silicon centers – ODC(II) in quartz and cristobalite glasses are presented. The luminescence and excitation spectra attributed to different local symmetry of ODC(II) were investigated under synchrotron excitation in the VUV region. The observed differences in the luminescence and excitation spectra of ODC(II) are caused by the environment and, therefore, short-range order in the samples.
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| 3. |
- Pimanov, D. A., et al.
(author)
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Efficiency of electron cooling in cold-electron bolometers with traps
- 2022
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In: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 13, s. 896-901
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Journal article (peer-reviewed)abstract
- Electron on-chip cooling from the base temperature of 300 mK is very important for highly sensitive detectors operating in space due to problems of dilution fridges at low gravity. Electron cooling is also important for ground-based telescopes equipped with 3He cryostats being able to function at any operating angle. This work is aimed at the investigation of electron cooling in the low -temperature range. New samples of cold-electron bolometers with traps and hybrid superconducting/ferromagnetic absorbers have shown a temperature reduction of the electrons in the refrigerator junctions from 300 to 82 mK, from 200 to 33 mK, and from 100 to 25 mK in the idle regime without optical power load. The electron temperature was determined by solving heat balance equa-tions with account of the leakage current, sixth power of temperature in the whole temperature range, and the Andreev current using numerical methods and an automatic fit algorithm.
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