scholarly journals Crystal Growth, Luminescence and Scintillation Characterizations of Cs2KLaCl6:Ce and Cs2KCeCl6

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Haoyu Wang ◽  
Jianhui Xiong ◽  
Man Li ◽  
Jufeng Geng ◽  
Shangke Pan ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Cubic Crystal ◽  
X Ray ◽  
Scintillation Crystals ◽  
Decay Times ◽  
Vertical Bridgman ◽  
Fluorescence Decay Time ◽  
Γ Rays

Elpasolite halides scintillation crystals have been proven to be very important materials for X-ray and γ-ray detector applications. The crystals of Cs2KLaCl6:4% Ce (CKLC) and Cs2KCeCl6 (CKCC) belong to novel scintillation of the Chloro-elpasolite crystal family. In this paper, the crystal growth of CKLC and CKCC crystals using the vertical Bridgman techniques were reported. The PXRD patterns showing both crystals have a cubic crystal structure. Both crystals have similar photoluminescence excitation and emission spectra, the fluorescence decay time of CKLC and CKCC crystals were about 49.7 and 33.8 ns. The energy resolution under the excitation of 662 keV γ-rays from a 137Cs source were found to be 6.6% and 5.2% (FWHM), respectively. The scintillation decay times of CKLC crystal were τ1 = 127 ns (33%) and τ2 = 1617 ns (67%), while that of CKCC crystal were τ1 = 2.86 ns (5%) and τ2 = 81 ns (95%).

Crystal growth of CuInSe2 by the Bridgman method

1989 ◽  
Vol 67 (4) ◽  
pp. 294-297 ◽  
Author(s):  
W. S. Weng ◽  
L. S. Yip ◽  
I. Shih ◽  
C. H. Champness
Keyword(s):  
Crystal Growth ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Bridgman Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Hall Effect Measurements ◽  
Rotation Technique ◽  
Crucible Rotation

Single crystals of CuInSe2 have been fabricated by the vertical Bridgman method. A conventional Czochralski crystal-pulling system was adapted for this purpose. An accelerated crucible-rotation technique was employed for a better mixing of the melt during the growth. Void- and crack-free crystal grains with an area as large as 50 mm2 and a thickness of more than 5 mm could be selectively cut from the ingots. From room-temperature Hall-effect measurements, mobility values as large as 73 cm2 ∙ V−1 ∙ s−1 were obtained for the present samples. X-ray diffraction studies suggested that abrasive polishing might create an amorphous layer on the surface of the CuInSe2 crystals.

Fluorescence Quenching and Solvation Processes of Fluorenone and 4-hydroxyfluorenone in Binary Solvents

2003 ◽  
Vol 58 (2-3) ◽  
pp. 144-156 ◽  
Author(s):  
M. Jozefowicza ◽  
J. R. Heldt ◽  
J. Karolczak ◽  
J. Heldt
Keyword(s):  
Hydrogen Bond ◽  
Photophysical Properties ◽  
Equilibrium Constants ◽  
Mixed Solvents ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Binary Solvents ◽  
Time Resolved ◽  
Decay Times ◽  
Fluorescence Light

Steady state and time-resolved spectroscopic measurements of fluorenone and 4-hydroxyfluorenone dissolved in binary nonpolar, polar and polar protic mixed solvents have been performed at room temperature. The absorption and emission spectra show that, apart from the free molecules, hydrogen bond complexes exist in the ground and excited states in the mixed solvents used. The data obtained were used to determine the stoichiometric equilibrium constants. The fluorescence decay data point that in the binary used solutions the radiation appears from an assembly of luminescence centers emitting fluorescence light of different wavelengths and decay times. Molecules forming simple hydrogen bond complexes (with fluorenone) show different photophysical properties from those where a proton-relay complex (with 4-hydroxyfluorenone) is established.

Concentration and Temperature Dependence of Laurdan Fluorescence in Glycerol

2003 ◽  
Vol 58 (9-10) ◽  
pp. 581-588 ◽  
Author(s):  
K. A. Kozyra ◽  
J. R. Heldt ◽  
J. Heldt ◽  
M. Engelkec ◽  
H. A. Diehl
Keyword(s):  
Steady State ◽  
Time Distribution ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Fluorescence Decay Time ◽  
Laurdan Fluorescence ◽  
Vibrational Equilibrium

Steady-state and time-resolved fluorescence measurements have been performed on Laurdan, dissolved in viscous glycerol, as functions of temperature and concentration. The results indicate spectral heterogeneity of the Laurdan solution. The fluorescence decay time distribution is attributed to radiative deexcitation of spatial conformational forms of locally excited (LE) and charge transfer (CT) states, the S1(CT)EQ state being in thermodynamic and vibrational equilibrium. The lifetimes and contributions of the different fluorescence modes depend on concentration and temperature. The excitation and emission spectra show discontinuous changes with increase of the Laurdan concentration.We suppose that the observed changes are caused by the formation of Laurdan micelle aggregates.

Growth and luminescence properties of Pr3+-doped LaCl3 single crystal

2016 ◽  
Vol 09 (02) ◽  
pp. 1650022
Author(s):  
Zihan Liu ◽  
Qinhua Wei ◽  
Laishun Qin ◽  
Hongsheng Shi ◽  
Kangying Shu
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Ultra Violet ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Xrd Pattern ◽  
X Ray ◽  
Decay Times ◽  
Vertical Bridgman ◽  
Dominant Peak

A transparent LaCl3:Pr[Formula: see text] single crystal with a dimension of [Formula: see text] [Formula: see text][Formula: see text]mm was grown by vertical Bridgman method. The differential scanning calorimetry (DSC) shows that the melting point of LaCl3:Pr[Formula: see text] crystal is about 841.5[Formula: see text]C. The powder X-ray diffraction (XRD) pattern proves the crystal structure of LaCl3:Pr[Formula: see text] is hexagonal with space group P63/m. There is a dominant peak centered at 335[Formula: see text]nm and a weaker peak located at 400[Formula: see text]nm under X-ray excitation, while three peaks located at 335[Formula: see text]nm, 356[Formula: see text]nm and 400[Formula: see text]nm under ultra-violet. The peaks of 335[Formula: see text]nm and 356[Formula: see text]nm can be ascribed to the transition of 5d–4f of Pr[Formula: see text], while the 400[Formula: see text]nm maybe related to LaCl3 host. Decay times were fitted to be about 14.5[Formula: see text]ns for 335[Formula: see text]nm, 14.6[Formula: see text]ns for 356[Formula: see text]nm and 1.3[Formula: see text]ns for 400[Formula: see text]nm. The experimental results show that the LaCl3:Pr[Formula: see text] crystal will be a promising scintillator.

Optical Properties and Characterization of Eu3+ Activated Pmma:Paac Copolymer Samples: Eu Concentration Effects

1999 ◽  
Vol 560 ◽  
Author(s):  
R. Sosa F. ◽  
M. Flores ◽  
R. Rodríguez T. ◽  
A. Munoz F.
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Spectroscopic Properties ◽  
Fluorescence Decay ◽  
Polymerization Process ◽  
Concentration Effects ◽  
Visible Absorption ◽  
Properties And Characterization ◽  
Decay Times ◽  
Fluorescence Decay Times

ABSTRACTSamples of Eu3+ -activated PMMA:PAAc copolymers were prepared in order to investigate their spectroscopic properties. The densities, refractive indices, UV-Visible absorption and emission spectra and fluorescence decay times were obtained experimentally. These data were used in conjunction with Judd-Ofelt theory to calculate the spontaneous emission probabilities and branching ratios, as a function of the europium content. The range of the concentration was 0.1 to 2.5 % mol. Our results are combined with previous information on the optical properties of rare-earth activated polymers in order to get a better understanding of the role played by the Eu3+ ions on the polymerization process in our samples.

Study of Te nanoprecipitates in CdZnTe crystals

2010 ◽  
Vol 25 (7) ◽  
pp. 1298-1303 ◽  
Author(s):  
Guoqiang Li ◽  
Shao-Ju Shih ◽  
Shichun Mu ◽  
Yadong Xu ◽  
Wanqi Jie
Keyword(s):  
Electron Microscopy ◽  
Crystal Growth ◽  
Point Defects ◽  
Local Density ◽  
Three Dimensional ◽  
High Quality ◽  
X Ray ◽  
Intrinsic Point Defects ◽  
Vertical Bridgman ◽  
Shed Light

In-depth studies of the two types of Te nanoprecipitates, linear and elliptic, in Cd1–xZnxTe (CZT) crystals grown by a modified vertical Bridgman method have been carried out. Electron diffraction suggests that linear Te nanoprecipitates align their Te atoms in a similar way to CZT structure, while elliptic Te nanoprecipitates cluster Te atoms following the pure trigonal Te structure. The three-dimensional morphology for both linear and elliptic Te nanoprecipitates has been revealed by delicate energy-dispersive x-ray analysis under electron microscopy. The density of elliptic Te nanoprecipitates ranges from 1015 to 1017 cm−3, while linear ones usually several times lower for a certain CZT wafer. The origin of both types of Te nanoprecipitates has been discussed in terms of the local density of intrinsic point defects in CZT. CZT properties are influenced more negatively by elliptic Te nanoprecipitates, which shed light on the methodology for crystal growth: preventing the clustering of intrinsic point defects during the crystal growth will be essential to obtain high quality CZT crystal.

A Modified Fast Analog Technique for Determining Luminescence Decay Times of Scintillators

1994 ◽  
Vol 348 ◽  
Author(s):  
L. Liu ◽  
W. Borst ◽  
C. Palsule ◽  
S. Gangopadhyay
Keyword(s):  
Fluorescence Decay ◽  
Luminescence Decay ◽  
Modified Technique ◽  
Ellipsoidal Mirror ◽  
Deconvolution Technique ◽  
Decay Times ◽  
Channel Plate ◽  
Fluorescence Decay Time ◽  
Trigger Mode ◽  
Fluorescence Decay Times

ABSTRACTWe have modified our previous fast analog technique to determine the luminescence decay times of scintillators following an excitation with a Sr90β3-source. In the original technique [1], the sample was excited with a nitrogen-pumped dye laser, and the fluorescence pulses (consisting of typically 50 to 1000 photons) were detected by a multi-channel plate photomultiplier tube (MCP-PMT). The output from the MCP-PMT was directed to a fast waveform digitizer triggered externally by the exciting laser. In the modified technique, the digitizer acquires the fluorescence decay in the internal trigger mode, as no corresponding external trigger pulse is available from the Sr90source. For efficient light collection from scintillators, an ellipsoidal mirror assembly has been tested. The fluorescence decays are acquired as multi-photon pulses and are subsequently corrected for the temporal instrument response by using a deconvolution technique. The overall time resolution of the technique is about 100 ps. The fluorescence decay time obtained using this technique for a commercial scintillator (SCSN-81) agrees well with literature. We also discuss our results on new epoxy-polymer based scintillators prepared in our laboratory. The primary motivation for this work was development of new scintillators with shorter fluorescence decay times for high collision rate experiments.

Optical Properties and Characterization of Eu3+ Activated Pmma:Paac Copolymer Samples: Eu Concentration Effects

1999 ◽  
Vol 558 ◽  
Author(s):  
R. Sosa F. ◽  
M. Flores ◽  
R. Rodríguez T. ◽  
A. Muñoz F.
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Spectroscopic Properties ◽  
Fluorescence Decay ◽  
Polymerization Process ◽  
Concentration Effects ◽  
Visible Absorption ◽  
Properties And Characterization ◽  
Decay Times ◽  
Fluorescence Decay Times

ABSTRACTSamples of Eu3+-activated PMMA:PAAc copolymers were prepared in order to investigate their spectroscopic properties. The densities, refractive indices, UV-Visible absorption and emission spectra and fluorescence decay times were obtained experimentally. These data were used in conjunction with Judd-Ofelt theory to calculate the spontaneous emission probabilities and branching ratios, as a function of the europium content. The range of the concentration was 0.1 to 2.5 % mol. Our results are combined with previous information on the optical properties of rare-earth activated polymers in order to get a better understanding of the role played by the Eu3+ ions on the polymerization process in our samples.

Preparation, structural characterization, and luminescence properties of Eu3+-doped nanocrystalline ZrO2

2005 ◽  
Vol 20 (10) ◽  
pp. 2780-2791 ◽  
Author(s):  
A. Speghini ◽  
M. Bettinelli ◽  
P. Riello ◽  
S. Bucella ◽  
A. Benedetti
Keyword(s):  
Sol Gel ◽  
Emission Spectra ◽  
Luminescence Properties ◽  
X Ray ◽  
Preparation Conditions ◽  
X Ray Scattering ◽  
Decay Times ◽  
Zirconia Nanopowders ◽  
Hydrolysis Of ◽  
Ray Scattering

Eu3+-doped zirconia nanopowders were prepared by the sol-gel technique using two different methods, based on the hydrolysis of zirconium n-propoxide, producing tetragonal and monoclinic zirconia under different preparation conditions. A detailed microstructure characterization was performed through wide angle x-ray scattering, small angle x-ray scattering, trasmission electron microscopy, and nitrogen physisorption measurements. The possible influence of the zirconia crystalline phases and particle sizes on the luminescence properties of the lanthanide ion was investigated. A detailed analysis of the emission spectra of the samples suggested that the dopant Eu3+ ions replace the Zr4+ ions in the zirconia crystal lattice. Moreover, samples prepared by the two different methods were characterized by different decay times of the Eu3+ ion luminescence.

UV and Visible Luminescence of Pr3+ Doped Oxides: New Materials

2008 ◽  
Vol 1111 ◽  
Author(s):  
Fabio Piccinelli ◽  
Adolfo Speghini ◽  
Konstantin Ivanovskikh ◽  
Andries Meijerink ◽  
Cees Ronda ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Significant Rise ◽  
Luminescence Spectroscopy ◽  
New Materials ◽  
Decay Kinetics ◽  
X Ray ◽  
Visible Luminescence ◽  
Decay Times ◽  
Kinetics Of ◽  
Defect Luminescence

AbstractThe garnet Ca3Sc2Si3O12 (CSSO) and the silico-carnotite Ca3Y2Si3O12 (CYSO) and Ca3Lu2Si3O12 (CLSO) materials, both undoped and doped with Pr3+, have been synthesized by solid state reaction at high temperature. The luminescence spectroscopy and the excited state dynamics of the materials have been studied upon VUV and X-ray excitation using synchrotron radiation. All doped samples have shown efficient 5d-4f emission upon direct VUV excitation of 5d levels, but only CSSO:Pr3+ shows luminescence upon interband VUV or X-ray excitation. The VUV excited emission spectra of CYSO:Pr3+ and CLSO:Pr3+ show features attributed to emission from two distinct sites accommodating the Pr3+ dopant. The decay kinetics of the Pr3+ 5d-4f emission in CSSO:Pr3+ upon VUV excitation across the conduction band are characterized by decay times in the range 25-28 ns with no significant rise after the excitation pulse. They appear to be faster upon X-ray irradiation than for VUV excitation. Weak afterglow components are attributed to defect luminescence.

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