The effects of hot axisymmetric compression to break down the primary carbide network of the H23 tool steels were studied. This current study only focused on one strain rate of 0.01 s -1 . The samples were deformed at 3 different temperatures (1000, 1050 and 1100 o C) with solutioning temperatures 1100 and 1250 o C, respectively. Afterwards, the samples were cooled by water quenching. The techniques used in this current study for investigation were the optical and electron microscopes and Vickers hardness test. The results show that hot axisymmetric compression had broken down the primary carbide network in the direction perpendicular to the compression axis and the carbides became finer. Although the highest hardness (274 HV) was achieved after solutioning at 1250 o C, followed by deformation at 1000 o C, however the microstructure analysis indicated that the optimum hot axisymmetric compression condition was solutioning at 1250 o C and deformation at 1000 o C.

Advanced Materials Research

Novel red emitting phosphors Mg3Y2Ge3O12:Sm3+ with high color purity and excellent thermal stability used in W-LEDs

Tunable luminescence properties of NaLa(MoO4)2:Ce3+,Tb3+ phosphors for near UV-excited white light-emitting-diodes

A single crystal scintillation material (Gd0.5–Y0.5)3Al2Ga3O12 (GYAGG) doped with Ce and codoped with Mg at a small concentration was grown by the Czochralski technique and studied for its scintillation properties for the first time. The Czochralski technique enabled this multi-ionic garnet to be produced from a melt in a single crystal form and allowed the problems of codoping peculiar to this material in a ceramic form to be solved. Due to codoping, the scintillation kinetics of a single crystal is shorter than that of GYAGG ceramics produced before. The scintillation properties of GYAGG were found to be superior to those of the solely Ce-doped or Mg-codoped Gd3Al2Ga3O12 crystal. The light yield of GYAGG:Ce,Mg was found to be 52 000 ph MeV−1, the coefficient of the light yield temperature dependence in the temperature range 20–100 °C was equal to 0.37%/°C, and the scintillation decay time constant was 50 ns.

Engineering of a new single-crystal multi-ionic fast and high-light-yield scintillation material (Gd0.5–Y0.5)3Al2Ga3O12:Ce,Mg

NaCaTiTaO6:Sm3+: A novel orange-red-emitting tantalate phosphor with excellent thermal stability and high color purity for white LEDs

Composition-property correlations have been systematically studied in the full concentration range of Y3Al5−xGaxO12:Ce (YAGG:Ce) scintillator crystals. The most promising compositions for new high energy physics experiments at colliders have been determined with the light output >200% relative to BGO and fast luminescence decay. Codoping with Ca2+ provides the decrease of phosphorescence intensity to 0.2% after 0.6 μs and shortening of the luminescence decay constant to 21 ns. Factors affecting the scintillation decay time in YAGG:Ce have been discussed. The crystals show weak transmission loss under γ-irradiation. The feasibility to produce YAGG:Ce fibers using the μ-PD method has been shown.

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Engineering of bulk and fiber-shaped YAGG:Ce scintillator crystals

A significant enhancement in the light attenuation length in 22 cm long YAG:Ce and YAG:Ce,Mg fibers grown by the micro-pulling-down method has been reported. This progress has been achieved by the introduction of Al excess into the melt, optimization of thermal conditions of crystallization and post growth annealing. Attenuation length clearly correlates with surface roughness of the fibers. Al excess addition over the stoichiometric composition enhances the fiber surface smoothness. An increase in axial thermal gradient and melt pressure in the crucible capillary die improves the crystallization process stability. Mg codoping provides a Ce3+ scintillation decay time decrease down to 80 ns.

Progress in fabrication of long transparent YAG:Ce and YAG:Ce,Mg single crystalline fibers for HEP applications

GAGG:Ce composite scintillator for X-ray imaging

Growth and characterization of tetragonal structure modification of β-Gd2Si2O7:Ce

The effect of irradiation on the scintillation light output, optical transmittance, and luminescent spectra of composite scintillators based on grains of single crystals Gd2SiO5:Ce (GSO) and Gd2Si2O7:Ce (GPS) is studied. The dielectric gel Sylgard-184 is the base and the binder for the grains inside the composite scintillator. The paper presents and analyzes the results obtained for the scintillators exposed by 10 MeV electrons from the linear electron accelerator at room temperature. The exposure doses D≤250 Mrad. The dose rate is 0.2 or 1500 Mrad/h. The study has shown that the composite scintillators based on the grains of GSO and GPS are radiation-resistant over the range of the irradiation.

Ia. Gerasymov

Papers

Engineering of bulk and fiber-shaped YAGG:Ce scintillator crystals

Progress in fabrication of long transparent YAG:Ce and YAG:Ce,Mg single crystalline fibers for HEP applications

GAGG:Ce composite scintillator for X-ray imaging

Growth and characterization of tetragonal structure modification of β-Gd2Si2O7:Ce

Radiation-resistant composite scintillators based on GSO and GPS grains