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We developed a modified micro-pulling-down (μ-PD) method for crystal growth of halide materials with hygroscopic nature. By the modified μ-PD method, CeCl3 and Ce doped LaBr3 [Ce: LaBr3] single crystals were grown and the crystals indicated high transparency. In the photoluminescence measurements, emissions of Ce3+ ion 5d-4f transition were observed in the both crystals of CeCl3 and Ce: LaBr3. Emission...
Europium-doped strontium iodide (SrI2:Eu) crystals are reported to be high light yield scintillator materials with good energy resolution, the best energy resolution of SrI2:Eu at 662 keV having reached 2.6%. To improve the crystals growth quality and to protect the crystals from hydration, it is practical to distinguish the pure crystals from impurity and structural defects by Raman spectroscopy...
A new family of Ce-containing scintillator materials is introduced. In this work, we report on the crystal growth of KGd2Cl7:Ce and CsGd2Cl7:Ce via the Vertical Gradient Freeze method. Various Ce concentrations from 0.5 to 10 at% have been tested to study the effect of dopant concentration on scintillation performance. Both KGd2Cl7:Ce and CsGd2Cl7:Ce have demonstrated good properties for gamma ray...
Rare earth (Pr, Nd and Tm) doped Lu2SiO5 (LSO) single crystals were grown by the micro-pulling down (μ-PD) method. The concentrations were added 0.05, 0.10, and 0.25% of Pr, 0.10, 0.25, and 0.50% of Nd, 0.1, 1, 10, and 100% of Tm with respect to Lu, respectively. Optical and radiation measurements were carried out on the samples. Pr samples have a transparency of about 80% in visible wavelength range...
Because of their high stopping power and fast and bright scintillation, cerium doped LSO and LYSO crystals have attracted a broad interest in the physics community pursuing precision electromagnetic calorimeter for future high energy physics experiments. Their excellent radiation hardness against γ-rays, neutrons and charged hadrons also makes them a preferred material for calorimeters to be operated...
KLi(Y1-xCex)F5 (x = 0.001, 0.01, 0.03) single crystals were grown from the melt using the precise atmosphere control type Micro-Pulling-Down (μ-PD) method to examine their potential as a new thermal neutron scintillators. The grown crystals were single-phase materials as confirmed by XRD. Ce3+ 5d-4f luminescence observed around 340 nm when exited by α-ray. The radio luminiscence measurements under...
A promising composition, Ce doped Cs2LiYBr6 (CLYB) originally introduced by van Loef et al. has been investigated recently as a gamma-ray and neutron detector. It belongs to the elpasolite family and has a cubic structure. A single crystal of this material has been grown using the vertical Bridgman method. Scintillation properties such as energy resolution, emission, light yield, non-proportionality,...
Thermal neutron imaging with Eu doped 6LiCaAlF6, which is a novel thermal neutron scintillator, was demonstrated. Eu doped 6LiCaAlF6 single crystal was grown by Czochralski technique and grown crystal was cut and polished to a plate shape. Setup of the thermal neutron imaging consisted of the plate shaped Eu doped 6LiCaAlF6, a position sensitive photomultiplier tube, Cd-mask and 252Cf in the polyethylene...
Recently a number of alkaline earth halide scintillators doped with Eu2+ have been reported on. They are characterized by very good proportionality, high up to 100,000 photons/MeV light yield, and very good energy resolution, as low as 2.8% at 662 keV. Yet, one of the issues facing these materials is radiation trapping. Radiation trapping results from a small Stokes shift that creates considerable...
Scintillation properties of Nd-doped Lu3Al5O12 (Nd:LuAG) single crystals grown by the micro-pulling down (μ-PD) method have been studied. The Nd concentration ranged from 0.1 to 3 mol%. The grown crystals were transparent and had a single-phase confirmed by powder XRD measurements. In transmittance spectra, they showed about 80% transmittance down to 300 nm and some weak 4f-4f absorption lines appeared...
Ce 0.1 % doped KLu2F7 single crystal was successfully grown from the melt by the modified micro-pulling-down (μ-PD) setup and quenching method. Transmittance, photoluminescence spectrum, photoluminescence decay time, radioluminescence decay time and light yield were measured. It showed more than 80 % transmittance and emission spectrum excited by 290 nm was observed around 377 nm. The decay time of...
We report on the development of a novel scintillator in which the decay time of its light emission varies continuously with the depth of an interaction in the crystal. The depth-of-interaction (DOI) information is thus encoded in the signal timing, which can be used to localize the position of the gamma interaction within the scintillator with high accuracy. This concept relies on the fact that decay...
A new family of Ce-containing scintillator materials is introduced. Single crystals of Cs3CeCl6, Cs3CeBr6, CsCe2Cl7 and CsCe2Br7 were grown in quartz ampoules by the Bridgman method. The crystals have been evaluated for application in gamma ray detection. The scintillation properties of these crystals such as emission, decay time, light output and energy resolution are presented. Radioluminescence...
The FMF is developing gamma ray detectors with Coplanar Grid (CPG) configuration based on (Cd, Zn)Te. The work is focused on the crystal growth of detector material as well as the development of read-out electronics and data acquisition systems (GMCA). In order to increase the active detector volume, several CPG detectors are stacked back to back. To improve overall quality of the energy spectrum...
The transient photocurrent kinetics of pure and doped TlBr detectors under γ-irradiation with 137Cs gamma-ray in dose rate range 0,033-3,84 Gy/min has studied. The crystals grew by Bridgman-Stockbarger directional solidification technique. Mass fraction of Pb or Ca introduced in the doped TlBr crystals were 1-10ppm and 150ppm respectively. The crystals grew in various atmospheres: vacuum, in the vapor...
Terahertz-range intracenter silicon lasers have demonstrated significant progress over past decade in expanding the frequency operation range, in manipulation of a silicon matrix as well as in lowering of optical pump threshold. While terahertz gain realized in silicon lasers has been already defined, optical losses in the active media have not been yet measured experimentally. We applied continuous...
Layer-by-layer infrared photoluminescence and photoreflectance measurements are performed on an HgCdTe epliayer. The Cd composition and impurity states along the growth direction are examined, and the vertical distribution is discussed.
In order to investigate the root causes of the good wire bonding reliability in electroless Ni/Pd/Au plating (ENEPIGEG), the wire bonding reliability of the combinations with electrolytic and electroless processes were evaluated. The reliability of ENEPIGEG and electrolytic Ni (SB-Watt)/IGEG were equivalent to that of the conventional electrolytic Ni (SB-Watt)/electrolytic Au and were excellent. The...
The ring patterned void distribution has been investigated by using numerical simulation. First, the mechanism of oxygen incorporation during Cz process was studied by calculating 3D melt flow. The silicon melt flow greatly affected the oxygen incorporation. In particular, the magnetic field plays a key role to control silicon melt flow in a large diameter crystal growth. In our experimental results,...
Controlled synthesis of ultra-long AlN nanowire arrays in different growth density has been successfully realized by direct nitridation of Al powders for the first time. These AlN nanowires have an average diameter of about 100 nm and their mean length is over 50 μm. All the synthesized ultra-long nanowires are pure single crystalline h-AlN structures with the growth orientation of [0001]. We propose...
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