Search

Eu-doped Li(Ca,Sr)AlF 6 [Eu:LiCSAF] single crystals with various Ca/Sr ratios were grown by the micro-pulling-down method, and their optical and scintillation properties were investigated to reveal the effects of Ca/Sr ratio on optical and scintillation properties of the Eu:LiCSAF single crystals. The Li(Ca 1− x − y Sr x Eu y )AlF 6 single crystals could be grown in 0 ≤  x  ≤ 0.1, 0.5 ≤  x  ≤ 1.0 and y  = 0.02 while the Eu:LiCSAF crystals with x  = 0.2, 0.25 and 0.4 included two colquiriite-type phases with different lattice parameters. The Li(Ca 1− x−y Sr x Eu y )AlF 6 single crystal with x  = 0.25 and y  = 0.02 showed the highest light yield under neutron irradiation. [ABSTRACT FROM AUTHOR]

Pr-doped SrI 2 (Pr:SrI 2 ) single crystals with various Pr concentrations were grown by the halide-micro-pulling-down (H-μ-PD) method, and the scintillation properties were investigated. Pr1%:SrI 2 single crystal with high transparency could be grown by the H-μ-PD method while Pr2, 3 and 5%:SrI 2 single crystals included some cracks and opaque parts. In the photoluminescence spectrum of the Pr1%:SrI 2 single crystal, an emission peak originated from the Pr 3+ ion was observed around 435 nm while the radioluminescence spectra showed an emission peak around 535 nm for the undoped SrI 2 and Pr:SrI 2 single crystals. Light yields of Pr1, 2, 3 and 5%:SrI 2 single crystals under γ-ray irradiation were 7700, 8700, 7200 and 6700 photons/MeV, respectively. Decay times of Pr1 and 2%:SrI 2 single crystals under γ-ray irradiation were 55.9 and 35.0 ns of the fast decay component, and 435 and 408 ns of the slow decay component, respectively. [ABSTRACT FROM AUTHOR]

Na co-doped Eu: LiCaAlF 6 (Eu, Na: LiCAF) single crystals were grown by the micro-pulling-down (μ-PD) method, and their optical and scintillation properties were examined to reveal the effects of the Na co-doping. The crystals were single-phase materials demonstrating structure isomorphic with that of undoped LiCAF. To perform the crystals characterization, the specimens with dimensions of several millimeters were cut from highly transparent and crack free fragments of the crystals and polished. It was observed that Na co-doping resulted modification of the transmittance and the excitation spectra, and increased the light yield detected under neutron irradiation. [ABSTRACT FROM AUTHOR]

We grew Lu-substituted CeBr 3 [(Ce 1− x Lu x )Br 3 ] crystals by a modified micro-pulling-down method to increase the effective atomic number and to investigate effects of the Lu substitution on the crystal growth, phase generation, chemical composition, and optical and scintillation properties. The (Ce 1− x Lu x )Br 3 crystals with x =0 and 0.01 had high transparency while the milky parts were generated in the crystals with x =0.05 and 0.20. By the analysis of chemical composition, the estimated Z eff increased to 47.9. On the other hand, the light yields were systematically decreased and decay times were increased with increasing Lu concentration. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the optical properties of 1mol% Nd-doped SrBr2 crystal grown by the Bridgman technique for an X-ray scintillator application. We succeeded in obtaining a transparent crystal, whose X-ray diffraction was measured under dry condition because of its hygroscopic nature. Roughly, we estimated that 90% of this crystal dissolved within 300min. under 25°C and 65–70% humidity. Under excitation by 270 and 400nm photons several emission peaks originating from 4F3/2 or 4G i1→4I i2 (i1=5/2 and 7/2 and i2=13/2, 11/2, and 9/2) transitions of Nd3+ were observed. 1mol% Nd:SrBr2 had a maximum quantum yield of approximately 45%. Additional emission peaks were observed under X-ray excitation. [Copyright &y& Elsevier]

Abstract: Nd, Ho, Er, and Tm doped lutetium aluminum garnet (LuAG) single crystals were grown using the micro-pulling down (μ-PD) method. The crystals were produced from the melts containing 3mol% of the dopants. The axial and radial dopant distribution were measured by electron probe micro analysis. Nd3+ and Ho3+ ions concentrated in the rim (k 0<1) and the radial concentration showed concave curvature. k 0 is the segregation coefficient of the dopant with respect to the given host phase. In the case of Er3+ and Tm3+ ions, the k 0 value is considered to be nearly 1 and the radial dopant distribution profiles were almost flat. [Copyright &y& Elsevier]

Abstract: We developed a modified micro-pulling-down (μ-PD) method for the crystal growth of halide materials with highly hygroscopic nature. A removable chamber system of the modified μ-PD method that can enter a globe box filled with Ar gas enabled to handle starting materials, set up a crucible and hot zone, grow a single crystal from the melt and take out a grown crystal without exposing to outside atmosphere. By the modified μ-PD method, CeCl3 and Ce 1% doped LaBr3 single crystals, which were famous as scintillator with high light yield and energy resolution were grown. Grown CeCl3 and Ce:LaBr3 single crystals indicated high transparency and they have no visible cracks and inclusions. In photoluminescence measurements, emission peak around 365nm was observed for CeCl3 single crystal and Ce:LaBr3 single crystal indicated two emission peaks around 360 and 380nm, which originated from 5d–4f transition of Ce3+ ion. [Copyright &y& Elsevier]

A vertical Bridgman (VB) crystal growth process was established using modified micro-pulling-down (μ-PD) crystal growth system with a removable chamber that was developed for the growth of deliquescent halide single crystals because conventional μ-PD method does not allow growth of large bulk single crystals. Eu:SrI 2 crystals were grown from the melt of (Sr 0.98 Eu 0.02 )I 2 composition using carbon crucibles. Undoped μ-PD SrI 2 crystals were used as seeds that were affixed to the bottom of the crucible. All the preparations preceding the growths and the hot zone assembling were performed in a glove box with Ar gas. Then the removable chamber was taken out of the glove box, attached to the μ-PD system, connected with a Turbo Molecular pump, and evacuated down to 10 −4 Pa at ~300 °C. After the baking procedure, high purity Ar gas (6N) was injected into the chamber. The crucible was heated by a high frequency induction coil up to the melting point of Eu:SrI 2 . After melting the starting materials, the crucible was displaced in downward direction for the crystal growth and then cooled down to room temperature. Thus, 2 in. and crack-free Eu:SrI 2 bulk crystals were produced. The crystals had high transparency and did not contain any visible inclusions. The crystals were cut and polished in the glove box and then sealed in an aluminum container with an optical window for characterization. The details of the crystal growth are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Ce:Gd3(Al x Ga1−x )5O12 (x=2.5/5 and 3/5, Ce:GAGG-2.5 and Ce:GAGG-3) crystals were grown by the Czochralski process in order to reduce cost of the starting materials as compared with conventional Ce:Gd3Al2Ga3O12 (Ce:GAGG-2) crystal which have high light output. Although perovskite phase was detected in Ce:GAGG-3, Ce:GAGG-2.5 had single-phase garnet structure. Solidification fraction for the Ce:GAGG-2.5 growth was 0.52. Optical properties including transmittance, emission, and excitation spectra of 30 samples cut from the Ce:GAGG-2.5 bulk ingot did not depend on their original position along the growth axis. These samples had light outputs of approximately 58,000±3000 photons/MeV. However, scintillation decay times varied from 140 to 200ns and depended on the position clearly. [Copyright &y& Elsevier]

In order to obtain new scintillators with high light output and high effective atomic number ( Z eff ), we performed anion-substitution for Cs 2 HfCl 6 (CHC) scintillator, and then, we succeeded in growing Cs 2 HfI 6 (CHI) single crystalline scintillator. It had Z eff of 58, which is the same as that of CHC, and had high light output of ∼70,000 photons/MeV with 700 nm emission. However, its scintillation decay time of ∼2.5 µs was slow for practical use as gamma-ray monitor. In this study, we performed Ce 3+ /Eu 2+ doping to Hf 4+ site to improve decay time of CHI, introducing the fast 5d-4f luminescence. Ce:CHI and Eu:CHI single crystals were finally obtained by the vertical Bridgman-Stockbarger method. The luminescence spectra of the Ce:CHI and Eu:CHI were very similar to that of the non-doped CHI, which would mean that no 5d-4f luminescence of Ce 3+ /Eu 2+ was observed. The measured light output and decay time of Ce:CHI were ∼48,000 photon/MeV and 2.3 ± 0.1 µs, respectively. As for Eu:CHI, light output and decay time were ∼69,000 photon/MeV and 2.8 ± 0.1 µs, respectively. [ABSTRACT FROM AUTHOR]

Ce0.5%: Ce:Gd 3 Ga 3 Al 2 O 12 (GGAG) single crystals co-doped with 500at.ppm Li + , Na + and K + were grown by using the micro-pulling down method. The smooth Ce 4+ charge transfer absorption below 350 nm and decay time acceleration were observed in Li co-doped sample. Na + and K + co-doping did not show a large effect on the acceleration of decay time compared with Li co-doping. Ce0.5%:GGAG single crystals co-doped with 500 at.ppm Li + were also grown by the Czochralski method. Optical, scintillation properties and timing performance were evaluated to investigate the effect of univalent alkali metal ions co-doping on Ce:GGAG scintillators. The scintillation decay curves were accelerated by Li co-doping: the decay time was significantly accelerated to 54.8 ns (47%) for the faster component and 158 ns (53%) for the slower component. The light output was 94% of the non co-doped Ce:GGAG standard. The coincidence time resolution was improved to 258 ps by Li co-doping. [ABSTRACT FROM AUTHOR]

Ce-doped (Gd, La) 2 Si 2 O 7 scintillation crystals are expected to be used as gamma-ray detectors for high temperature measurement. To realize scintillators for high temperature environment, we investigated (Ce 0.01 Gd 0.59−x La 0.40 Y x ) 2 Si 2 O 7 (x = 0.00, 0.05, 0.10, 0.15) single crystals grown by the micro-pulling-down method. The results showed that a 5% Y-admixed Ce-doped (Gd, La) 2 Si 2 O 7 scintillator can yield higher light output when compared with Y-free Ce-doped (Gd, La) 2 Si 2 O 7 scintillator. The light outputs at 25°C and 175°C were determined to be ∼43,000 and ∼40,000 photons/MeV, respectively. Moreover, 1 inch size 5% Y-admixed Ce-doped (Gd, La) 2 Si 2 O 7 scintillator was grown by the Czochralski technique, and its light output at 175°C kept the value of around 95% of the value at 25°C. [ABSTRACT FROM AUTHOR]

1 in. diameter Mg 0.05, 0.1, 0.2, 0.5 mol% and Zr 0.015% co-doped Ce1%:GGAG crystals were grown by Cz method. Relationship between Mg concentration and absorption, luminescence, light output, decay time, timing resolution was investigated. Mg 0.2 mol% co-doped sample showed the fastest timing resolution of 165 ps among the Mg-co-doped samples. [ABSTRACT FROM AUTHOR]

Ce-doped Lu 2 Si 2 O 7 scintillator contains radioactive isotope 176 Lu which causes an unwanted intrinsic background signal. The development of scintillators with reduced Lu concentration were required in some applications. In this study, we developed the Gd admixed lutetium pyrosilicate, where the average ion radius at the rare earth site was similar to the Tm 3+ ion radius, for which the RE 2 Si 2 O 7 (RE=Tm, Yb, Lu) crystal structure is stable from room temperature to melting point. We have grown (Ce x Lu 1−x−y Gd y ) 2 Si 2 O 7 (x=0.01, y=0.00, 0.05, 0.10) single crystals. Their crystal systems were monoclinic with a space group C 2/ m . The absorption spectra revealed the energy transitions in Ce and Gd ions might be occurred. The light output was degraded and decay time was accelerated comparing the Gd 5% admixed sample with the Gd 10% one. [ABSTRACT FROM AUTHOR]

Mg co-doped Ce1%:Gd 3 Ga x Al 5−x O 12 (Ce:GAGG) crystals (x=2.4, 2.7, 3.0) were successfully grown by the Czochralski (Cz) method. Effect of Mg co-doping on the scintillation properties of Ce:GAGG was examined. This study covers measurements of solidification fraction and scintillation properties such as light yield, energy resolution and non-proportionality for each crystal. Pulse-height spectra of various gamma and X-ray sources with energies ranged from 30 keV to 662 keV were measured. Regardless of the presence/absence of Mg dopant, the non-proportionality curves with lower content of gallium in the crystal structure tend to improve. Mg co-doped Ce:GAGG samples did not show a significant difference as compared with non co-doped Ce:GAGG. Mg co-doped crystals with x=2.4 and 2.7 showed the promising scintillation properties of faster decay time and higher energy resolution than those with x=3.0. [ABSTRACT FROM AUTHOR]

The growth conditions of Ce-doped Gd 2 Si 2 O 7 crystals, using the infrared convergent heating floating zone method, were optimized to make the shape of the crystal-melt interface flat or convex. The shape of the crystal-melt interface, meaning the interface between the molten zone and the grown crystal, was evaluated quantitatively using the convexity ( h/r ) as a parameter. The h/r value was found to be systematically dependent on the crystal diameter, the focus position of the ellipsoidal mirror for infrared convergent heating, and the lamp power used during crystal growth. For an 8.2-mm-diameter crystal grown using conventional conditions, the h/r value was −0.8, which indicates that the crystal-melt interface had a concave shape. The h/r value increased with the position of the ellipsoidal mirror, going from −0.8 for the −8 mm mirror position, to −0.5 for the +6 mm mirror position. Lastly, when the lamp power increased from 5.8 to 7.0 kW, the h/r value increased from −0.6 to −0.3, which was the maximum value observed, indicating that a flat or convex crystal-melt interface was not obtained. [ABSTRACT FROM AUTHOR]

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]

Growth of 2-in. diameter Ce-doped (La , Gd) 2 Si 2 O 7 (La-GPS) scintillating crystals by Czochralski method using Ir crucible is reported. The composition of the host material was approximately equal to La 0.5 Gd 1.5 Si 2 O 7 and the concentration of the Ce 3+ -activator was either 0.5 or 1.5 at.% with respect to the total content of the rare-earths forming the host crystal matrix. Effects of the hot zone construction including inductive coil position, presence/absence of the after-heater, rotation rate and other growth parameters on the crystal quality are discussed in some details. The crystals produced in optimized conditions were colorless, transparent, uniform in their shape, crack- and inclusions-free, and demonstrated smooth glass-like surface. The length of the crystals’ cylindrically-shaped body parts exceed 100 mm. The growth results were well reproducible. The main disadvantage of the growth process is associated with short lifetime of the Ir crucible and its deformation caused by thermal expansion of the pre-solidified melt at each heating stage. [ABSTRACT FROM AUTHOR]

The 3 in. size Ce1%:Gd 3 Al 2 Ga 3 O 12 single crystals were prepared by the Czochralski (Cz) method. Optical constants were measured. Chemical composition analysis and uniformity of scintillation decay and light yield along growth direction were evaluated. The timing resolution measurement for a pair of 3 mm×3 mm×3 mm size Ce:GAGG scintillator crystals was performed using Si-PMs. [ABSTRACT FROM AUTHOR]

The Li + co-doped Ce:Lu 3 Al 5 O 12 single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of the co-doping. The smooth Ce 4+ CT absorption below 350 nm is clearly enhanced with increasing concentration of Li. The scintillation decays were accelerated and light yields were increased by Li co-doping. [ABSTRACT FROM AUTHOR]

Ce 1% doped Lu 2 Gd 1 Al 2 Ga 3 O 12 (LGAGG) single crystals with a diameter of 50 mm and length of 150 mm were grown by the Czochralski (Cz) method using an RF heating system. The EPMA techniques is employed to check homogeniousity of chemical composition. Luminescence and scintillation properties were also evaluated. The grown LGAGG showed light yield of around 25,000 photon/MeV and energy resolution was 9.8%@662 keV. The scintillation decay time was 53.6 ns at room temperature. [ABSTRACT FROM AUTHOR]

• Ce doped LaCl 3 /AECl 2 (AE = Mg, Ca, Sr) eutectics were grown by BS method. • In case of AE = Mg, Ca, eutectic with PSSFs structures were observed. • The Ce:LaCl 3 /CaCl 2 eutectic showed Ce3+ 4f-5d emission at 345 nm. • The light output of Ce:LaCl 3 /CaCl 2 under 137Cs was 9000 photons/MeV. • The scintillation decay time under 137Cs was 26.8 ns (26%) and 282 ns (74%). Ce-doped LaCl 3 /AECl 2 (AE = Mg, Ca, Sr) system eutectics were explored. Ce-doped LaCl 3 / AECl 2 (AE = Mg, Ca, Sr) eutectics were grown using the Bridgman–Stockbarger method in quartz ampoules. In the case of AE = Mg, Ca, eutectics with submicron-diameter phase-separated scintillator fibers (PSSFs) structure were observed. In the case of AE = Sr sample, a solid solution of La 0.708 Sr 0.292 Cl 2.708 was observed. The plate sample from the grown eutectics has some transparency. The grown eutectic structure showed a mixture of rods and plates shape. This mixed structure was aligned with a length of around 100–400 μm. The Ce:LaCl 3 /CaCl 2 eutectic showed 345 nm emission ascribed to Ce3+ 4f-5d transition under X-ray excitation. The Ce:LaCl 3 /CaCl 2 sample resulted in the highest light output of 9,000 photon/MeV, which is comparable to the previously reported eutectic scintillator Ce:GdAlO 3 /α-Al 2 O 3 , 9500 photon/MeV. Scintillation decay time of the Ce:LaCl 3 /CaCl 2 sample under 662 keV gamma-ray excitation was 26.8 ns (26%) and 282 ns (74%). [ABSTRACT FROM AUTHOR]

Abstract: Nd and Yb doped CaYAlO4 crystals have been grown by the micro-pulling down method. The segregation coefficient along the growth direction and the radial dopant distribution were measured by using electron probe micro-analysis (EPMA). The X-ray induced luminescence spectra in the spectral range from 300 to 1500nm were measured: Nd and Yb doped CaYAlO4 showed intense peaks at 990 and 1045nm, respectively. These crystals would be promising materials for near infrared emission scintillators. [Copyright &y& Elsevier]

Abstract: The Nd-doped Lu3Al5O12 (Nd:LuAG) single crystal was grown by the Czochralski (CZ) method. In XRC profiles, the full-width at half-maximum (FWHM) value was 58arcsec, which was much higher than that of the μ-PD (194arcsec). In photo and radio-luminescence spectra, the CZ grown sample showed strong emission peaks attributed to Nd3+ 4f–4f transitions in visible wavelengths longer than 400nm. The Nd:LuAG grown with the CZ method showed light yield of 7900 photons/MeV, which is comparable with the standard BGO and energy resolution of 14% under 137Cs γ-ray excitation. [Copyright &y& Elsevier]

Abstract: We have investigated optical and scintillation properties of Cr-doped YAlO3 (Cr:YAP) single crystals with different Cr concentrations. Cr:YAP crystals were grown by the micro-pulling-down (μ-PD) method. The grown crystals had a single-phase confirmed by the powder XRD analysis. For all the Cr-doped samples, a peak positioned near 700nm wavelength dominates the spectra. It can be ascribed to the Cr3+ 2E→4A2 emission. In X-ray induced radioluminescence spectra, 2E→4A2 emissions were observed. The light output of Cr 0.5%:YAP under X-ray excitation was more than twice as high as the standard CdWO4. [Copyright &y& Elsevier]

Abstract: Single crystals of undoped and Ce3+-doped Ca3(BO3)2 (CBO) are grown by the Czochralski (CZ) method with an RF heating system. Undoped CBO crystal has high transmittance in the 190–900nm wavelength range, while the absorption bands were observed around 275 and 350nm due to the transition from the 4f ground state levels of 2F5/2 and 2F7/2 to Ce3+ 5d excited state in Ce3+-doped one. The photoluminescence spectrum of Ce3+-doped CBO crystal showed strong emission band around 400nm under both 275 and 350nm excitation due to the 5d–4f transition of Ce3+. In the measurement of pulse height spectra under 241Am 5.5MeV α-ray excitation, Ce3+-doped CBO showed higher energy resolution compared with that of crystal grown by the micro-pulling down (μ-PD) method. [Copyright &y& Elsevier]

Abstract: Optical properties, including optical transmittance, absorption coefficient, refractive index, and dielectric constant, of Sr7%, Ce15% co-doped GdF3 crystal grown by the Czochralski method are discussed. Moreover, α-ray responses, including emission spectrum, pulse height spectrum, and decay time, are also presented. This is the first report on refractive index, dielectric constant, and light yield under α-ray irradiation of the Sr:Ce:GdF3 single crystal. [Copyright &y& Elsevier]

Abstract: (Na0.425−x Lu0.575+x−y Eu y )F2.15+2x (x=0, ±0.05, y=0.001, 0.01, 0.05) single crystals were grown from the melt by the precise atmosphere control type micro-pulling-down (μ-PD) method. The grown crystals were single-phase materials that were confirmed by X-ray diffraction, and their lattice constants increased when substitution of Lu with Eu increased. The crystals demonstrated about 90% transmittance in the 400–900nm region that decreased with greater doping with Eu or Na. In all the crystals, strong absorption resulted from Eu2+ 5d–4f transition was observed around 200–350nm. Eu2+ 5d–4f photoluminescence and radioluminescence under α-ray excitation were also detected. The crystals with low content of Eu or Na had high photoluminescence intensity; however, the radioluminescence intensity was extremely low. Intensity of the Eu3+ 4f–4f emission increased with increase in Eu concentration. Formation of Eu2+ in the grown crystals was also detected especially in those that had low content of Eu and Na. [Copyright &y& Elsevier]

Abstract: The growth of Y2O3, Sc2O3, and Lu2O3 single crystals using the micro-pulling-down method is reported. Crystallinity, optical transmittance, and scintillation characteristics including emission spectra, pulse height spectra, and decay kinetics under α-ray excitation of the grown crystals were studied. The light yields of Y2O3, Sc2O3, and Lu2O3 crystals were estimated from the pulse height spectra excited by 241Am 5.5MeV α-rays, in about 920±92ph/5.5MeVα, 370±37ph/5.5MeVα, and 150±15ph/5.5MeVα, respectively. The scintillation decay times of Y2O3, Sc2O3, and Lu2O3 crystals were estimated with following fast/slow parameters 30.1/184, 14.6/51.3, and 16.7ns, respectively. Furthermore, α-ray imaging was performed using Y2O3 crystal. [Copyright &y& Elsevier]

• A novel ternary CsI/KI/KCl eutectic scintillator is reported. • Directionally solidified eutectic was grown using the Bridgman–Stockbarger method. • The expected Tl+ emission peak near 486 nm was observed in the CsI phase. • The decay time of the eutectic was 313 ns. • The light output of the eutectic was approximately 22,000 photons/MeV. In this study, Tl:CsI/KI/KCl eutectic scintillators were grown using the Bridgman–Stockbarger method by unidirectional solidification. The eutectic phases were uniformly distributed in the transverse direction and were slightly aligned along the growth direction. The Tl:CsI scintillator phase was grown as a matrix, which was then used for creating optical waveguides of the scintillation light. The expected Tl+ emission peak was observed at 486 nm under X-ray excitation and cathodoluminescence; this was attributed to the self-trapped exciton perturbed by TI+ in Tl:CsI. The decay time of the Tl:CsI/KI/KCl eutectic was 313 ns, and its light output was estimated to be 22,000 photons/MeV. [ABSTRACT FROM AUTHOR]

• (Ce 0.015 La 0.600 Y 0.385) 2 Si 2 O 7 single crystal was grown by the micro-pulling-down method. • Quenching temperature of (Ce 0.015 La 0.600 Y 0.385) 2 Si 2 O 7 was determined to be 526 K. • Light output of (Ce 0.015 La 0.600 Y 0.385) 2 Si 2 O 7 was determined to be ~12,000 photons/MeV. 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 (T 50%) 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. [ABSTRACT FROM AUTHOR]

Abstract: Some pyrosilicate scintillators such as Ce:Gd2Si2O7 and Ce:Lu2Si2O7 have a good light output, and especially Ce:(Gd,La)2Si2O7 has an excellent light output of over 36,000ph/MeV. In order to search novel scintilators, we have developed a pyrogermanate-based scintillation material (Ce0.01,Gd0.90,La0.09)2Ge2O7 using the floating zone method. Although the light output was decreased due to quenching, 5d–4f transition of Ce3+ was observed around 480nm in photo- and radio-luminescence spectra. This emission wavelength was longer than that of (Ce0.01,Gd0.90,La0.09)2Si2O7 with an emission wavelength of 390nm. [Copyright &y& Elsevier]

• 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]

• Feasibility of the growth of LYSO, YSO, LuAG, YAG and GAGG by EFG was studied. • Aluminate such LuAG and YAG had the least reactivity with Mo metal. • Ce:LuAG with 320 mm length were grown by 4 multiple EFG using Mo crucible and die. • Light yield value was high and nearly constant within 25,000–27,200 photon/MeV. Edge defined Film Fed Growth (EFG) method with molybdenum (Mo) crucible and die was studied for the growth of several oxide-based single crystals. At first, reactivity between the molybdenum (Mo) metal and oxide melts of Ce:(Lu,Y) 2 SiO 5 (LYSO) Ce:Y 2 SiO 5 (YSO), Ce:Gd 3 (Al,Ga) 5 O 12 (GAGG), Ce:Lu 3 Al 5 O 12 (LuAG), Ce:Y 3 Al 5 O 12 (YAG) was investigated. The experimental and calculation results on the reactivity with Mo show that the aluminum garnets (LuAG, YAG) had the smallest reactivity with Mo metal. On the contrary, GAGG showed the strongest reaction with Mo. Then, the multiple-die grown shaped single crystal growth of Ce:LuAG was demonstrated by EFG method. Single crystal plates up to 320 mm in length were grown successfully. The homogeneity of dopant distribution, Mo contamination, luminescence and scintillation responses of the grown crystals were evaluated. [ABSTRACT FROM AUTHOR]