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0.5, 1, 2, and 5% Er-doped La 3 Ga 5 SiO 14 (LGS) single crystals were synthesized by the Floating Zone method and the photoluminescence (PL) and scintillation properties were characterized. Emission peaks appeared at visible–near-infrared (NIR) regions. Their spectral features matched with those due to the 4f–4f transitions of Er3+. The PL quantum yields of 0.5, 1, 2, and 5% Er-doped samples were respectively 45.0, 73.3, 82.5, and 69.4%. The decay times due to the 2H 9/2 –4I 15/2 transitions of Er3+ were obtained when visible ranges were monitored under excitation of both visible lights and X-rays. All the prepared samples showed good linearity between the X-ray exposure dose rate and scintillation signals in NIR ranges. The best lower detection limit in prepared samples was 5 mGy/h recorded by the 2% Er-doped LGS. • Er-doped La 3 Ga 5 SiO 14 single crystals were synthesized by the Floating zone method. • Luminescence due to 4f–4f transitions of Er3+ was observed in both visible and near-infrared regions. • Quantum yields of 0.5, 1, 2, and 5% Er-doped samples were respectively 45.0, 73.7, 82.5, and 69.4%. • The best lower detection limit in prepared samples was 5 mGy/h obtained by 2% Er-doped sample. [ABSTRACT FROM AUTHOR]

• CaNb 2 O 6 , as a new intrinsic scintillator was firstly reported. • The influences of the growth atmosphere on the optical and scintillation properties were investigated. • Crystals grown in an O 2 atmosphere displayed higher quantum efficiency, X-ray luminescence intensity, light yield, and lower afterglow. Single crystal CaNb 2 O 6 was grown by the optical floating-zone method and characterized for a new intrinsic scintillator. Under Ar and O 2 growth atmospheres, the as-grown crystal rods (Ф 4–5 mm) exhibit a greyish and a colorless appearance, respectively, which are related with the oxygen vacancy. They both show a broad emission band with the maximum at 480 nm under UV excitation, while the one grown in O 2 is brighter with a photoluminescence quantum efficiency of 44%. Consequently, a 25% higher scintillation light yield was obtained in the crystals grown in O 2 compared to those in Ar. The other scintillation properties including radioluminescence spectrum, pulsed X-ray decay and afterglow were also characterized and compared. [ABSTRACT FROM AUTHOR]

Effects of the tungsten (W) ions co-doping on the crystal growth, optical and scintillation properties for the Czochralski (Cz) grown Ce:Gd3Ga3Al2O12(GGAG) single crystals were investigated. The W 0%, 0.1%, 0.3%, 1%, and 5% co-doped Ce 1%:GGAG single crystals with a diameter of 1 in and length of 60–80 mm were grown by the Cz method. The effective segregation coefficient of the W ions was found as 0.002, 0.001, and 0.005 for W 0.1%, 0.3%, and 1%, Ce:GGAG, respectively. The segregation of W ions in GGAG host, light yield, and scintillation decay of the W co-doped Ce:GGAG were evaluated. The light yield decreased as the concentration of W co-dopant increased and toward the tail of the crystal. Furthermore, the defect role and related charge trapping in the W co-doped crystals were monitored by the thermo-stimulated luminescence. [ABSTRACT FROM AUTHOR]

• Eu concentration dependences of SrI 2 :Eu properties are analyzed. • Energy resolution better 4% sustains even at Eu concentration as low as 0.3 at%. • Scintillation properties of SrI2:Eu do not depend on growth method (Czochralski or Bridgman). SrI 2 :Eu crystals with the activator content of 0.1–5.5% were grown by the Bridgman-Stockbarger technique. The dependences of light yield, energy resolution, optical and luminescent properties on the Eu concentration have been studied. It has been shown that with a decrease in the amount of activator to 0.3% Eu, the energy resolution at 662 keV remains below 4%. The light yield gradually diminishes with decreasing Eu concentration. This makes it possible to revise the required amount of the expensive activator for growing high performance SrI 2 :Eu crystals. Scintillation parameters of crystals grown by the Czochralski and Bridgman-Stockbarger technique have been compared. [ABSTRACT FROM AUTHOR]

Unidirectional (<200> plane) 1, 3, 5-triphenylbenzene (3PB) single crystal 150 mm long and 25 mm diameter was grown by SR technique. The grown crystal was subjected to UV–vis-NIR spectral analysis determine linear optical properties over the range of 200–1100 nm. The relevant optical parameters such as transmittance, absorption coefficient, extinction coefficient, band gap energy, reflectance, and refractive index were determined which reveal the suitability of crystal to couple with a photomultiplier tube or other light sensor. The wide band gap energy 3.65 eV of the 3PB crystal shows significant transmittance in the Vis and NIR region. The refractive index of the crystal is determined to be constant above 350 nm, and it confirms the required parameter to set high light yield. The temperature dependence refractive index was measured in the range of 30–70 °C, it illustrates the faster propagation light in the crystal. Third order nonlinear optical parameters of the grown crystal were estimated by Z-scan technique. It showed that the low absorption coefficient and negative refractive index. The second order hyperpolarizability (γ) of 3PB molecule was found to be 8.6411 × 10 −34 esu. The obtained all results in the present work which makes the 3PB crystal promising candidate for optical power limits, optical switching and other nonlinear optical applications. The Laser Damage Threshold (LDT) was determined to be 2.1612 GW/cm 2 and it confirms the suitability of crystal for device fabrication. [ABSTRACT FROM AUTHOR]

A new tantalum silicate, Rb 4 Ta 2 Si 8 O 23 , was synthesized as high-quality single crystals by the high temperature flux growth method. Rb 4 Ta 2 Si 8 O 23 was found to exhibit intense blue luminescence and scintillation as a self-activated luminescent silicate. Rb 4 Ta 2 Si 8 O 23 crystallizes in the triclinic space group P 1 ‾ with lattice parameters of a = 6.8916(2) Å, b = 7.7669(2) Å, c = 11.0018(3) Å, α = 76.3110(10)°, β = 89.2560(10)°, and γ = 71.8090(10)°. The structure consists of corner-sharing SiO 4 tetrahedra forming infinite ribbons connected by isolated TaO 6 octahedra. The synthesis, structure, and optical properties are reported, notably, bright blue scintillation when exposed to X-rays. The scintillation of Rb 4 Ta 2 Si 8 O 23 was quantitatively evaluated by radioluminescence (RL) measurements and was determined to be ∼47% of BGO powder. [Display omitted] • Rb 4 Ta 2 Si 8 O 23 was synthesized using flux crystal growth. • The crystal structure was solved using single crystal X-ray diffraction. • Rb 4 Ta 2 Si 8 O 23 exhibits photoluminescence and scintillation. • Scintillation intensity was quantitatively determined to be 47% of BGO powder from RL measurements. [ABSTRACT FROM AUTHOR]

The luminescence and scintillation properties of SrI 2 :0.5%Yb 2+ have been investigated. SrI 2 :Yb single crystals were grown by the vertical Bridgeman method from the melt. They showed a light yield of 38,400 ph/MeV and energy resolution of 12.5% for the 662 keV full absorption peak. Yb 2+ photoluminescence intensity and decay time were studied between 78 and 600 K. Two emission bands centered at 418 and 446 nm were observed and ascribed to spin-allowed and spin-forbidden Yb 2+ 5d-4f transitions, respectively. Their corresponding room-temperature decay time constants are 710 ns and 77 μs. Both, the emission intensities and the decay time constants vary with temperature. The obtained results were interpreted using a model of self-absorption of Yb 2+ emission and a model of non-radiative relaxation of the electron from the low spin to the high spin 4f 13 5d Yb 2+ excited states. The radiative lifetime of the low spin Yb 2+ excited state was determined as 400 ns. [ABSTRACT FROM AUTHOR]

Single crystal growth of novel dicesium molybdate (Cs 2 MoO 4) crystal by Czochralski technique was carried out. The single crystal phase was confirmed by powders X-ray diffraction analysis. The optical band gap of 4.22 eV was estimated from the absorbance spectra, measured at room temperature. The luminescence properties were measured under the excitation of 4.42 eV UV light from an LED source in the temperature range of 10–300 K. The photoluminescence light yield increases upon cooling down the grown crystal to 10 K. The luminescence decay time was analyzed with the sum of three exponential decay-time functions in the entire temperature range. The comparison of luminescence light yield with Li 2 MoO 4 (one of the promising scintillating bolometers for the neutrinoless double-beta decay search) at 10 K shows a similar light output. These preliminary investigations show that the grown crystal can be a good candidate crystal for the cryogenic dark matter and neutrinoless double-beta decay search. • The Cs 2 MoO 4 crystal has been grown by Czhochrlaski method for the 1st time. • Optical band gape of 4.22 eV was estimated from absorption spectrum. • A comparable luminescence yield with that of Li 2 MoO 4 crystal was obtained at 10 K. • The slow decay component was fitted with the three-level thermal quenching model. • This crystal has the potential to be used for the 0νββ decay search of 100Mo. [ABSTRACT FROM AUTHOR]

Ce:Li 6 Y(BO 3) 3 (LYBO) is a promising thermal neutron scintillator that can be grown into bulk single crystals by the Czochralski method although it melts incongruently. This study achieves 1-inch Ce:LYBO, and demonstrates the collateral flux-growth of LiY 6 O 5 (BO 3) 3 (LYOB) single crystals at the bottom of the crucible during the pulling of LYBO from a stoichiometric melt. Both LYBO and LYOB belong to monoclinic crystal system with the same space group. Thermal analysis shows that LYOB itself is more incongruent than LYBO, decomposing mainly into Y 16.86 B 8 O 38 phase when heated up to 1500 ​°C. In contrast to the typical bluish emission of Ce-doped scintillators, like the case of Ce:LYBO, Ce:LYOB crystals exhibit a broad emission peaking in the orange wavelength region, as a result from an extraordinarily large Stokes shift. The ultrafast photoluminescence (PL) decay of Ce:LYOB is due to dominant non-radiative processes that also cause obvious luminescence quenching. This study reports for the first time high-quality Ce:LYOB single crystals, which are characterized in terms of single crystal diffraction, thermal analysis, optical transmittance, excitation and PL at room temperature, PL decay and Raman spectroscopy. Simultaneous crystal growth of 1-inch Ce:Li 6 Y(BO 3) 3 and millimeter high-quality Ce:LiY 6 O 5 (BO 3) 3 , and investigations on their structure, thermal analysis and optical properties. [Display omitted] • 1-inch Ce:Li 6 Y(BO 3) 3 crystal that is transparent and cracks/inclusion-free. • Flux-growth of high-quality Ce:LiY 6 O 5 (BO 3) 3 single crystals. • Thermal and optical properties of Ce:LiY 6 O 5 (BO 3) 3 were reported for the first time. • Ce:LiY 6 O 5 (BO 3) 3 emits an orange-reddish light originating from large Stokes shift. [ABSTRACT FROM AUTHOR]

The luminescence, scintillation, and photoconversion properties of the single crystals of Ce3+ doped Tb 3−x Gd x Al 5-y Ga y O 12 (х = 0–1.5; у = 2–2.5) mixed garnets, grown by the micro-pulling-down (μ-PD) method, are investigated as a function of the Tb/Gd ratio with the aim of development of phosphor-convertors of white LED and scintillators. The partial Tb3+ substitution by Gd3+ cations leads to the suitable change of the crystal field splitting of the 5d energy levels of Ce3 ions due to different sizes of the Gd3+ and Tb3+ cations. For this reason, the cation engineering enables to improve the luminescence and scintillation characteristics of Tb 3−x Gd x Al 3-2.5 Ga 2-2.5 O 12 crystals due to increasing the efficiency of Gd3+→ Tb3+→ Ce3+ cascade energy transfer observed in these solid solutions. We have shown that from all the crystals under study, the Tb 3-x Gd x Al 2.5 Ga 2.5 O 12 :Ce (х = 1–1.5) crystal is the best promising candidate for the photoconversion and scintillation applications. • Single crystals of TbGdAGG:Ce grown by the micro-pulling-down method. • Tb3+/Gd3+ ratio control improving the color rendering and scintillation properties. • The best photoconversion properties are shown by Tb 2-1.5 Gd 1-1.5 Al 2.5 Ga 2.5 O 12 :Ce. [ABSTRACT FROM AUTHOR]

• W co-doped Ce:Gd 3 Ga 3 Al 2 O 12 with 30–60 mm length grown by micro-pulling down method. • Light yield value was increased by small amount (200–1000 ppm) of W co-doping. • When the co-doping concentration of W was higher than 1000 ppm, the light yield decreased. Single crystal scintillators are extensively used in various radiation detection applications and their scintillation performances can be improved via co-doping. Therefore, in this study, tungsten-ion co-doped Ce:Gd 3 (Ga,Al) 5 O 12 (Ce:GGAG) crystals were grown using the micro-pulling-down (μ-PD) method to investigate the effects of co-doping on their scintillation properties. The relationships between the W concentration, optical and luminescence properties, and radiation response of the W-co-doped Ce:GGAG crystals were evaluated. The W-co-doped Ce 0.5%:Gd 3 Ga 3 Al 2 O 12 single crystals of diameter 3 mm and length 30–60 mm were grown by the μ-PD method. The light yield increased at W concentrations of 200 and 500 ppm and decreased at W concentrations above 1000 ppm. There was no significant change in the fast decay component of scintillation. [ABSTRACT FROM AUTHOR]

• Cs 2 HfCl 6 single crystal preparation by miniaturized and standard Bridgman methods. • Cs 2 HfCl 6 single-phase proved by XRD measurements. • Room temperature optical, luminescence, and scintillation properties of Cs 2 HfCl 6. • Room temperature photoluminescence and scintillation decay kinetics of Cs 2 HfCl 6. Time and cost effective methods are highly desirable in research and development of new scintillators. Modern techniques like micro-pulling down (μ-PD) are suitable for material screening but are unfit for the growth of some crystals. These crystals must be grown by different methods that are usually very time demanding. Modification of halide μ-PD apparatus by custom made elements allowed us to grow cesium hafnium chloride (Cs 2 HfCl 6) by vertical Bridgman method (VB) with significantly reduced growth time. Structural and optical properties of samples prepared from as-grown crystals were studied and compared to crystals grown by standard VB method. The X-ray diffraction confirmed the formation of cesium hafnium chloride single-phase and natural cleavage of the crystals along the (1 1 1) crystallographic plane. Photoluminescence emission, excitation, absorption, and radioluminescence spectroscopy revealed that the optical quality of the crystals grown by modified VB method was comparable to the quality of the crystals grown by standard VB method. Therefore we can use samples prepared by modified VB to estimate and optimize the performance of Cs 2 HfCl 6 based crystals in scintillation detectors. This setup allows the time and cost-effective material screening and it is a powerful tool for the development of new halide based single crystal scintillators. [ABSTRACT FROM AUTHOR]

Single crystal growth of undope CaCl 2 , CaBr 2 and CaI 2 was performed by Bridgman–Stockbarger (BS) method. Investigations of their crystal phases, luminescence and scintillation properties such light yield, energy resolution decay time were performed. In addition, linearity of gamma-ray response in 32–1275 keV range were also evaluated. The light output of 106,000 photon/MeV, energy resolution of 3.2%@662 keV, and scintillation decay time of 834 ns (84%) 1460 ns (16%) were observed. Luminescence properties of CaBr 2 also firstly reported. [ABSTRACT FROM AUTHOR]