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CsCu2I3 crystal is a promising Cu-based halide material for scintillation detection. In this paper, Na+ ion-doped CsCu2I3 crystals with a size of ϕ12 mm × 50 mm were grown successfully using the vertical Bridgman method, and the properties were systematically investigated. CsCu2I3:Na crystals exhibit yellow light emission peaking at 575 nm and a large Stokes shift of 1.55 eV. Based on the results of the XRD and XPS, the Na+ was introduced successfully. The optical absorption spectra show that the band gap of CsCu2I3 crystals was narrowed when the Na+ was doped. The photoluminescence quantum efficiency (PLQY) is improved from 16.4% to 19.6%. Finally, the X-ray-induced afterglow, and scintillation (energy resolution, light yield and decay time) under a 137Cs source were measured and discussed. These results illustrate that CsCu2I3:Na crystals have potential applications in the radiation detection field. [ABSTRACT FROM AUTHOR]

Ce0.03Gd2.97Ga2Al3O12 (Ce:GGAG) single crystals were successfully grown by the traveling solvent floating zone method (TSFZ). A series of compositions, where the mole ratio is Gd2O3 : Al2O3 = 25 : 75, 27 : 73, 29 : 71, were investigated as solvents. The 25 mol% Gd2O3-75 mol% Al2O3 solvent component was found to be the most effective in stabilizing the molten zone to obtain a crystal rod with uniform diameter. The crystal cracks were relieved clearly due to the improved molten zone stabilization during the crystal growth process. XRD patterns of the obtained crystals prove the garnet structure without any evident second phase. The characteristic Ce3+ emission located at around 540 nm was presented in the photoluminescence and X-ray excited luminescence spectra. The scintillation light yield reaches up to 34 132 pho MeV−1 and scintillation decay time was optimized to 64 ns with a high fast decay component of about 85%. The TSFZ method demonstrated the growth feasibility of Ce:GGAG crystals that have an incongruent-melting trend with lower Ga/Al ratio in the compositions. [ABSTRACT FROM AUTHOR]

Cerium-doped 1% Ce:GdYGaAlO(GYGAG) single crystal samples grown via Czochralski method were annealed under air, O and N atmospheres from 350 to 1400 °C. The X-ray excited luminescence spectra, energy spectra and UV as well as thermally stimulated luminescence (TSL) spectra were performed comparatively on 'as-grown' and thermally annealed samples. It was found that the luminescence efficiency after annealing in air and O was significantly enhanced compared to the non-annealed samples and this phenomenon was suggested to be caused by the existence of some oxygen vacancies in the Ce:GYGAG crystals. And the oxygen vacancies in the as-grown GYGAG crystals can be effectively eliminated by means of annealing in O containing atmosphere without changing the luminescence mechanism. From the TSL curves before and after annealing, three traps within 77-650 K were found to be related to oxygen vacancies. [ABSTRACT FROM AUTHOR]

• High quality NaI:Tl and NaI:Tl,Li single crystals with a size of 11 mm in diameter and 135 mm in length were grown by the multi-ampoule Bridgman method. • The effective segregation coefficients of Tl and Li in NaI single crystals were estimated as 0.26 and 0.35, respectively. • The radioluminescence spectra under X-ray excitation, pulse height spectra and scintillation decay kinetics under γ-ray excitation of the samples taken from different solidification positions in NaI:Tl and NaI:Tl,Li single crystals were systematically studied. In this work, high quality NaI:Tl and NaI:Tl,Li single crystals with a size of 11 mm in diameter and 135 mm in length were grown by the multi-ampoule Bridgman method. The concentrations of Tl and Li ions along the solidification direction were measured by the inductively coupled plasma optical emission spectrometer. The effective segregation coefficients of Tl and Li in NaI single crystals were estimated as 0.26 and 0.35, respectively. The radioluminescence spectra under X-ray excitation, pulse height spectra and scintillation decay kinetics under γ-ray excitation of the samples taken from different solidification positions in NaI:Tl and NaI:Tl,Li single crystals were systematically studied. For RL spectrum and scintillation decay time, there is a negligible position-dependent difference for both NaI:Tl and NaI:Tl,Li single crystals. In contrast, the energy resolution at 662 keV gradually deteriorates along the solidification direction, and the light yield maintains almost the same until reaching the last-to-freeze region. [ABSTRACT FROM AUTHOR]

• The optimal non-stoichiometric ratio for growing Cs 2 LiYCl 6 :Ce crystals was obtained. • High quality Cs 2 LiYCl 6 :Ce single crystals codoped with Ca2+ and Sr2+ ions were grown by the Multi-ampoule Bridgman method. • The energy resolution of Cs 2 LiYCl 6 :Ce was improved from 4.6 % to 3.8 % by co-doping 0.05 % Sr2+. Cs 2 LiYCl 6 :Ce is a novel scintillation crystal with good energy resolution, high light yield, and outstanding neutron/gamma discrimination capability. However, its complex composition and incongruent melting behavior pose many challenges to the crystal growth. In this study, five different compositions of Cs 2 LiYCl 6 :Ce crystals were grown using the vertical Bridgman method. These compositions included LiCl at 57 mol%, 60 mol%, and 63 mol%, as well as CsCl and YCl 3 at ratios of 1.9:1 and 2.1:1. It was found that the highest CLYC phase volume fraction could be obtained in the recipe with a LiCl composition of 60 mol%, while changing the ratio of CsCl to YCl 3 did not show any significant positive effect on crystal growth. In addition, Ca2+/Sr2+ was applied to modify the scintillation performance of CLYC:Ce. A batch of Φ11mm crystals with different co-doping concentrations of Ca2+ and Sr2+ were successfully grown by using the Multi-ampoule Bridgman method, no cracks or inclusions were observed in the grown crystals. Co-doping showed little effect on the radiation luminescence and transmittance spectra of CLYC. The scintillation decay curves demonstrated that the decay times depend on the co-doping concentration. Most notably, the energy resolution of CLYC:Ce is improved from 4.6 % to 3.8 % by co-doping 0.05 % Sr2+ under 662 keV gamma-ray excitation. However, the light yield is reduced because of co-doping of Ca2+ and Sr2+, especially Ca2+ having a more pronounced effect. [ABSTRACT FROM AUTHOR]

Highlights • Transparent CLLC crystals of were grown using the vertical Bridgman method. • Stoichiometric CLLC powder melts incongruently between 343 and 442 °C. • Stokes shift of CLLC is about 1358 cm−1. • The photoluminescence decay time of CLLC crystal is 34.6 ns. • The energy resolution of the Cs 2 LiLaCl 6 crystal with 0.5at% Ce was 7.1% at 662 keV. Abstract Cs 2 LiLaCl 6 :Ce (CLLC) is a promising scintillator material for dual gamma/neutron detection. The vertical Bridgman technique, with a LiCl-rich melt and high axial temperature gradient, was used to grow transparent CLLC crystals for the first time. The stoichiometric CLLC powder melted incongruently with a melting range of 343–442 °C. Additional LiCl suppressed the formation of Cs 3 LaCl 6 second phase, which was identified in crystals grown from stoichiometric melts. CLLC was found to have a Stokes shift of about 1358 cm−1 and a photoluminescence decay time of 34.6 ns. Direct electron-hole capture by Ce3+ ions and core-valence luminescence were the main contributors to the X-ray induced luminescence spectrum. A ∅9 × 8 mm3 cylinder of the CLLC crystal with 0.5at% Ce had an energy resolution of 7.1% at 662 keV. The scintillation decay times of the CLLC crystal excited with 662 keV gammas were 79 ns and 1491 ns. [ABSTRACT FROM AUTHOR]

Multicomponent garnets, due to their excellent light yield and energy resolution, become one of the most promising scintillators used for homeland security and nuclear non-proliferation applications. This work focuses on the optimization of Ce-doped (Gd,Y) 3 (Ga,Al) 5 O 12 scintillators using a combination strategy of pre-screening and scale-up. Ce-doped Gd x Y 1− x Ga y Al 5− y O 12 ( x =1, 2 and y =2, 2.2, 2.5, 2.7, 3) polycrystalline powders were prepared by high-temperature solid state reaction method. The desired garnet phase in all the samples was confirmed using X-ray diffraction measurement. By comparing the radioluminescence intensity, the highest scintillation efficiency was achieved at a component of Gd 2 Y 1 Ga 2.7 Al 2.3 O 12 :Ce powders. A (Gd 2 Y 1 )Ga 2.7 Al 2.3 O 12 doped with 1% Ce single crystal with dimensions of Ø35×40 mm was grown by Czochralski method using a <111> oriented seed. Luminescence and scintillation properties were measured. An optical transmittance of 84% was achieved in the concerned wavelength from 500 to 800 nm. Its 5d–4f emission of Ce 3+ is at 530 nm. The light yield of a Ce1%: Gd 2 Y 1 Ga 2.7 Al 2.3 O 12 single crystal slab at a size of 5×5×1 mm 3 can reach about 65,000±3000 Ph/MeV along with two decay components of 94 and 615 ns under 137 Cs source irradiation. [ABSTRACT FROM AUTHOR]

LiCaAlF 6 single crystals doped with different Eu concentrations varied from 1 at% to 5 at%, and LiCaAlF 6 :Eu single crystals co-doped with 3 at%Cu+, 2 at%Mg2+, 2 at%Ba2+ were grown by the Bridgman method in non-vacuum atmosphere. Their optical and scintillation performances were studied. The optimal scintillation efficiency was achieved in the LiCaAlF 6 :Eu single crystals with Eu concentrations between 2 and 2.5 at%. The influences of Cu+, Mg2+ and Ba2+ co-doping on optical properties, scintillation yield, scintillation decay and defect structures were studied. It was found that the Cu+ co-doping can improve the scintillation efficiency. The Mg2+ and Ba2+ co-doping have negligible effects on light yield. • Bridgman method in non-vacuum atmosphere were used to grow LiCaAlF 6 :Eu crystals. • The optimal scintillation efficiency obtained between 2 and 2.5 at%Eu concentration. • The Eu–Cu co-doping improve the scintillation efficiency than Eu doped LiCaAlF 6. • The Eu–Cu co-doping changed the defect structure than Eu doped LiCaAlF 6. [ABSTRACT FROM AUTHOR]