E. Garibin - Academia.edu (original) (raw)
Papers by E. Garibin
Inorganic Materials, 2016
Physics of Particles and Nuclei Letters, 2016
Optics and Spectroscopy, 2014
Bulletin of the Russian Academy of Sciences: Physics, 2011
Inorganic Materials, 2014
ABSTRACT This paper examines how the transformation of BaF2 from a single-crystalline to polycrys... more ABSTRACT This paper examines how the transformation of BaF2 from a single-crystalline to polycrystalline state as a result of uniaxial hot-forming influences its properties. With increasing strain, the microstructure of the material changes from a nonuniform polycrystalline one, with a block size of about 1 mm, to a classic ceramic structure made up of grains in which dislocations form walls, resulting in a subgrain structure. The best mechanical characteristics are offered by the ceramic produced at a strain on the order of 700%. The intensity of the fast X-ray luminescence component (band at 220 nm) is independent of strain, whereas that of the slow component (band at 310 nm) decreases with increasing strain.
Inorganic Materials, 2014
Inorganic Materials: Applied Research, 2011
ABSTRACT The real structure of samples of optical fluoride ceramics is studied by atomic force, s... more ABSTRACT The real structure of samples of optical fluoride ceramics is studied by atomic force, scanning electron, and transmission electron microscopy. It is shown that the optical ceramic samples based on CaF2 have a lamellar structure, and the distance between lamellae is 25–50 nm. Most likely, lamellae have a twin nature. For BaF2 ceramic, lamellae are not typical, and they are concentrated near grain boundaries.
Inorganic Materials, 2012
ABSTRACT We have studied the pulsed cathodoluminescence spectra and kinetics of CaF2:Yb2+,Yb3+ (3... more ABSTRACT We have studied the pulsed cathodoluminescence spectra and kinetics of CaF2:Yb2+,Yb3+ (3 mol % YbF3) single crystals and pressed samples under excitation with nanosecond electron pulses and determined the characteristic times and intensities of nanosecond and microsecond emission decay components at temperatures from 15 to 300 K. The results demonstrate that deformation pressing in vacuum at 1150°C followed by annealing in a CF4 atmosphere at 1180°C has an insignificant effect on the emissive properties of CaF2:Yb2+,Yb3+.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009
We suggest the use of crystal of BaF 2 as scintillator in Positron Emission Tomography (PET) with... more We suggest the use of crystal of BaF 2 as scintillator in Positron Emission Tomography (PET) with very high space resolution at the level of 1-2 mm. These crystals are prospective candidates to provide necessary cell granularity (crystal+photodetector) of 2 Â 2 mm 2 and they possesses a very short decay time ($0.8 ns) of the fast component in the emission spectrum. In order to detect this emission lying within deep ultra-violet (UV) spectral range with wavelengths 195-240 nm we propose to develop new type of photodetecting devices. These ones are based on wide band gap group-III nitride compounds (A 3 N) having an adjustable spectral sensitivity at wavelengths 210-360 nm and quantum efficiency 10-15%. The principal schemes of such devices based on A 3 N-nanoheterostructures emitting photoelectrons into vacuum or gaseous atmosphere and detector of photoelectrons are discussed in this paper. The photo-device with parallel-plane gas positron sensitive detector having time and position resolutions 1 ns and 500 mm, respectively, can work at counting rate up to 10 8 ph cm À2 s À1 . Fig. 3. Scheme of PET sensor.
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
ABSTRACT In this work the spectroscopic and luminescent properties of CaF2-TmF3 (4 mol.%) were in... more ABSTRACT In this work the spectroscopic and luminescent properties of CaF2-TmF3 (4 mol.%) were investigated: The spectra of absorption for transitions from ground level 3H6 to exited multiplets 3F4,3H5,3H4,3F3, and 1G4 of Tm3+ ions and spectrum of luminescence for transition 3F4->;3H6 were registered for CaF2-TmF3 (4 mol.%) ceramics. Lifetimes of levels 3H4,3F4 of Tm3+ ions in CaF2-TmF3 (4 mol.%) were measured. The absorption and emission cross-sections of CaF2-TmF3 (4 mol.%) ceramics calculated by Fuchtbauer-Ladenburg method.
Inorganic Materials, 2012
ABSTRACT The thermal conductivity of Ca1 − x Hox F2 + x (x ≤ 0.03) optical ceramics has been stud... more ABSTRACT The thermal conductivity of Ca1 − x Hox F2 + x (x ≤ 0.03) optical ceramics has been studied experimentally in the temperature range 50–300 K. With increasing holmium content, the thermal conductivity of the ceramics decreases, especially at low temperatures: from 10.2 to 2.3 W/(m K) at 300 K and from 250 to 4.5 W/(m K) at 50 K.
Inorganic Materials, 2013
ABSTRACT The heat capacity of single crystals of the Ca1 − x Erx F2 + x (x = 0.05, 0.10) and Ca0.... more ABSTRACT The heat capacity of single crystals of the Ca1 − x Erx F2 + x (x = 0.05, 0.10) and Ca0.95Yb0.05F2.05 fluorite solid solutions was determined by adiabatic calorimetry in the temperature range 55–300 K. The results were used to obtain temperature dependences of the Debye characteristic temperature, entropy, and enthalpy for the solid solutions.
Quantum Electronics, 2009
The optical characteristics of two Russian-made CaF2 ceramic samples are compared to those of sin... more The optical characteristics of two Russian-made CaF2 ceramic samples are compared to those of single-crystal CaF2. The results indicate that the ceramic possesses high optical quality and a small absorption coefficient (~10-3 cm-1 at a wavelength of 1.07 mum) and is suitable as a material for optical components. Experimental evidence is presented for spatial modulation of the thermally induced depolarisation
Quantum Electronics, 2012
The structure and the spectral-luminescent properties of CaF 2 -TmF 3 fluoride ceramics and singl... more The structure and the spectral-luminescent properties of CaF 2 -TmF 3 fluoride ceramics and single crystals are studied. AFM investigations revealed a layered nanostructure of grains, which was not observed in reference samples of single crystals. It is found that the spectral-luminescent properties of CaF 2 -TmF 3 ceramics and single crystals are similar. Lasing at the 3 F 4 ® 3 H 6 transition of Tm 3+ ions in CaF 2 -TmF 3 ceramics (wavelength 1898 nm) under diode pimping is obtained for the first time.
Physics of the Solid State, 2010
ABSTRACT Optical characteristics of BaF2 and BaF2: Ce single crystals and nanoceramic materials p... more ABSTRACT Optical characteristics of BaF2 and BaF2: Ce single crystals and nanoceramic materials prepared from these single crystals by uniaxial hot pressing have been studied. It has been shown that the introduction of Ce3+ ions into BaF2 hardly affects the ultrafast (∼0.9 ns) luminescence component. The integrated luminescence intensity of the BaF2: Ce nanoceramics is higher than that of the corresponding single crystal and considerably higher that the intensity of the undoped BaF2 crystal. It has been demonstrated that the slow (several hundred nanoseconds) component of the luminescence decay of BaF2: Ce is due to the energy transfer from excitons to Ce3+ ions.
Optics and Spectroscopy, 2011
The specificity of additive coloring of CaF 2 optical ceramic (formation of color centers in it a... more The specificity of additive coloring of CaF 2 optical ceramic (formation of color centers in it and photothermochemical transformation of these centers in colored ceramic samples) has been considered. Under the same coloring conditions, this process occurs more slowly in ceramics rather than in crystals; at the same time, the limiting concentration of color centers that can be introduced into ceramics is much higher. The photothermochemical transformations of color centers in crystals and ceramics, which occur under illumination at different wavelengths and upon heating, have been studied. The specific features of introduction of color centers into ceramic and their transformation under illumination and heating are likely to be related to the mass twinning of ceramic grains.
Optical Materials, 2013
ABSTRACT CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical prope... more ABSTRACT CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical properties as starting single crystals. Slope efficiency of the Сa0.95Yb0.05F2.05 is equal to 35% in the pulsed mode of laser operation. Decrease of ytterbium concentration in CaF2:Yb samples down to 3 mol.% resulted in the essential improvement of Сa0.97Yb0.03F2.03 thermal conductivity from 3.5 to 4.5 W/m K, but slightly decreased (down to 30%) slope efficiency of the samples under both pulsed and CW mode of operation. Alternative hot-pressing synthesis of CaF2:Yb fluoride laser ceramics provided materials with superior mechanical properties (microhardness Н = 3.2 GPa and fracture toughness К1С = 0.65 МPа m1/2) in comparison with hot-formed and/or single crystal CaF2:Yb specimens. For the first time, lasing has been observed for the novel aforementioned hot-pressed CaF2:Yb ceramics.
Journal of Physics: Conference Series, 2012
ABSTRACT Because of the recent technology progress in the synthesis of fluoride ceramics by so-ca... more ABSTRACT Because of the recent technology progress in the synthesis of fluoride ceramics by so-called hot-pressing method, several cooperating research groups have produced and meticulously described various polycrystalline ceramic samples with optical characteristics similar to the properties of corresponding single crystals. Their achievements made fluoride optical materials less expensive, more diverse and easier available for the use in solid-state lasers. The present review covers studies of fluoride ceramic materials and their properties in the last fifty years. It describes the most significant results obtained by leading scientific groups and indicates the most promising directions where research of fluoride laser ceramics should proceed in near future.
IEEE Transactions on Nuclear Science, 2000
Inorganic Materials, 2016
Physics of Particles and Nuclei Letters, 2016
Optics and Spectroscopy, 2014
Bulletin of the Russian Academy of Sciences: Physics, 2011
Inorganic Materials, 2014
ABSTRACT This paper examines how the transformation of BaF2 from a single-crystalline to polycrys... more ABSTRACT This paper examines how the transformation of BaF2 from a single-crystalline to polycrystalline state as a result of uniaxial hot-forming influences its properties. With increasing strain, the microstructure of the material changes from a nonuniform polycrystalline one, with a block size of about 1 mm, to a classic ceramic structure made up of grains in which dislocations form walls, resulting in a subgrain structure. The best mechanical characteristics are offered by the ceramic produced at a strain on the order of 700%. The intensity of the fast X-ray luminescence component (band at 220 nm) is independent of strain, whereas that of the slow component (band at 310 nm) decreases with increasing strain.
Inorganic Materials, 2014
Inorganic Materials: Applied Research, 2011
ABSTRACT The real structure of samples of optical fluoride ceramics is studied by atomic force, s... more ABSTRACT The real structure of samples of optical fluoride ceramics is studied by atomic force, scanning electron, and transmission electron microscopy. It is shown that the optical ceramic samples based on CaF2 have a lamellar structure, and the distance between lamellae is 25–50 nm. Most likely, lamellae have a twin nature. For BaF2 ceramic, lamellae are not typical, and they are concentrated near grain boundaries.
Inorganic Materials, 2012
ABSTRACT We have studied the pulsed cathodoluminescence spectra and kinetics of CaF2:Yb2+,Yb3+ (3... more ABSTRACT We have studied the pulsed cathodoluminescence spectra and kinetics of CaF2:Yb2+,Yb3+ (3 mol % YbF3) single crystals and pressed samples under excitation with nanosecond electron pulses and determined the characteristic times and intensities of nanosecond and microsecond emission decay components at temperatures from 15 to 300 K. The results demonstrate that deformation pressing in vacuum at 1150°C followed by annealing in a CF4 atmosphere at 1180°C has an insignificant effect on the emissive properties of CaF2:Yb2+,Yb3+.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009
We suggest the use of crystal of BaF 2 as scintillator in Positron Emission Tomography (PET) with... more We suggest the use of crystal of BaF 2 as scintillator in Positron Emission Tomography (PET) with very high space resolution at the level of 1-2 mm. These crystals are prospective candidates to provide necessary cell granularity (crystal+photodetector) of 2 Â 2 mm 2 and they possesses a very short decay time ($0.8 ns) of the fast component in the emission spectrum. In order to detect this emission lying within deep ultra-violet (UV) spectral range with wavelengths 195-240 nm we propose to develop new type of photodetecting devices. These ones are based on wide band gap group-III nitride compounds (A 3 N) having an adjustable spectral sensitivity at wavelengths 210-360 nm and quantum efficiency 10-15%. The principal schemes of such devices based on A 3 N-nanoheterostructures emitting photoelectrons into vacuum or gaseous atmosphere and detector of photoelectrons are discussed in this paper. The photo-device with parallel-plane gas positron sensitive detector having time and position resolutions 1 ns and 500 mm, respectively, can work at counting rate up to 10 8 ph cm À2 s À1 . Fig. 3. Scheme of PET sensor.
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
ABSTRACT In this work the spectroscopic and luminescent properties of CaF2-TmF3 (4 mol.%) were in... more ABSTRACT In this work the spectroscopic and luminescent properties of CaF2-TmF3 (4 mol.%) were investigated: The spectra of absorption for transitions from ground level 3H6 to exited multiplets 3F4,3H5,3H4,3F3, and 1G4 of Tm3+ ions and spectrum of luminescence for transition 3F4->;3H6 were registered for CaF2-TmF3 (4 mol.%) ceramics. Lifetimes of levels 3H4,3F4 of Tm3+ ions in CaF2-TmF3 (4 mol.%) were measured. The absorption and emission cross-sections of CaF2-TmF3 (4 mol.%) ceramics calculated by Fuchtbauer-Ladenburg method.
Inorganic Materials, 2012
ABSTRACT The thermal conductivity of Ca1 − x Hox F2 + x (x ≤ 0.03) optical ceramics has been stud... more ABSTRACT The thermal conductivity of Ca1 − x Hox F2 + x (x ≤ 0.03) optical ceramics has been studied experimentally in the temperature range 50–300 K. With increasing holmium content, the thermal conductivity of the ceramics decreases, especially at low temperatures: from 10.2 to 2.3 W/(m K) at 300 K and from 250 to 4.5 W/(m K) at 50 K.
Inorganic Materials, 2013
ABSTRACT The heat capacity of single crystals of the Ca1 − x Erx F2 + x (x = 0.05, 0.10) and Ca0.... more ABSTRACT The heat capacity of single crystals of the Ca1 − x Erx F2 + x (x = 0.05, 0.10) and Ca0.95Yb0.05F2.05 fluorite solid solutions was determined by adiabatic calorimetry in the temperature range 55–300 K. The results were used to obtain temperature dependences of the Debye characteristic temperature, entropy, and enthalpy for the solid solutions.
Quantum Electronics, 2009
The optical characteristics of two Russian-made CaF2 ceramic samples are compared to those of sin... more The optical characteristics of two Russian-made CaF2 ceramic samples are compared to those of single-crystal CaF2. The results indicate that the ceramic possesses high optical quality and a small absorption coefficient (~10-3 cm-1 at a wavelength of 1.07 mum) and is suitable as a material for optical components. Experimental evidence is presented for spatial modulation of the thermally induced depolarisation
Quantum Electronics, 2012
The structure and the spectral-luminescent properties of CaF 2 -TmF 3 fluoride ceramics and singl... more The structure and the spectral-luminescent properties of CaF 2 -TmF 3 fluoride ceramics and single crystals are studied. AFM investigations revealed a layered nanostructure of grains, which was not observed in reference samples of single crystals. It is found that the spectral-luminescent properties of CaF 2 -TmF 3 ceramics and single crystals are similar. Lasing at the 3 F 4 ® 3 H 6 transition of Tm 3+ ions in CaF 2 -TmF 3 ceramics (wavelength 1898 nm) under diode pimping is obtained for the first time.
Physics of the Solid State, 2010
ABSTRACT Optical characteristics of BaF2 and BaF2: Ce single crystals and nanoceramic materials p... more ABSTRACT Optical characteristics of BaF2 and BaF2: Ce single crystals and nanoceramic materials prepared from these single crystals by uniaxial hot pressing have been studied. It has been shown that the introduction of Ce3+ ions into BaF2 hardly affects the ultrafast (∼0.9 ns) luminescence component. The integrated luminescence intensity of the BaF2: Ce nanoceramics is higher than that of the corresponding single crystal and considerably higher that the intensity of the undoped BaF2 crystal. It has been demonstrated that the slow (several hundred nanoseconds) component of the luminescence decay of BaF2: Ce is due to the energy transfer from excitons to Ce3+ ions.
Optics and Spectroscopy, 2011
The specificity of additive coloring of CaF 2 optical ceramic (formation of color centers in it a... more The specificity of additive coloring of CaF 2 optical ceramic (formation of color centers in it and photothermochemical transformation of these centers in colored ceramic samples) has been considered. Under the same coloring conditions, this process occurs more slowly in ceramics rather than in crystals; at the same time, the limiting concentration of color centers that can be introduced into ceramics is much higher. The photothermochemical transformations of color centers in crystals and ceramics, which occur under illumination at different wavelengths and upon heating, have been studied. The specific features of introduction of color centers into ceramic and their transformation under illumination and heating are likely to be related to the mass twinning of ceramic grains.
Optical Materials, 2013
ABSTRACT CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical prope... more ABSTRACT CaF2:Yb fluoride laser ceramics, prepared by hot-forming, exhibit the same optical properties as starting single crystals. Slope efficiency of the Сa0.95Yb0.05F2.05 is equal to 35% in the pulsed mode of laser operation. Decrease of ytterbium concentration in CaF2:Yb samples down to 3 mol.% resulted in the essential improvement of Сa0.97Yb0.03F2.03 thermal conductivity from 3.5 to 4.5 W/m K, but slightly decreased (down to 30%) slope efficiency of the samples under both pulsed and CW mode of operation. Alternative hot-pressing synthesis of CaF2:Yb fluoride laser ceramics provided materials with superior mechanical properties (microhardness Н = 3.2 GPa and fracture toughness К1С = 0.65 МPа m1/2) in comparison with hot-formed and/or single crystal CaF2:Yb specimens. For the first time, lasing has been observed for the novel aforementioned hot-pressed CaF2:Yb ceramics.
Journal of Physics: Conference Series, 2012
ABSTRACT Because of the recent technology progress in the synthesis of fluoride ceramics by so-ca... more ABSTRACT Because of the recent technology progress in the synthesis of fluoride ceramics by so-called hot-pressing method, several cooperating research groups have produced and meticulously described various polycrystalline ceramic samples with optical characteristics similar to the properties of corresponding single crystals. Their achievements made fluoride optical materials less expensive, more diverse and easier available for the use in solid-state lasers. The present review covers studies of fluoride ceramic materials and their properties in the last fifty years. It describes the most significant results obtained by leading scientific groups and indicates the most promising directions where research of fluoride laser ceramics should proceed in near future.
IEEE Transactions on Nuclear Science, 2000