Effect of the europium doping on the structural and luminescent properties of yttrium aluminum garnet

2013 ◽  
Vol 178 (4) ◽  
pp. 248-253 ◽  
Author(s):  
L.E. Muresan ◽  
E.J. Popovici ◽  
I. Perhaita ◽  
E. Indrea ◽  
T.D. Silipas
Author(s):  
Gulnur Alpyssova ◽  
Victor Lisitsyn ◽  
Mikhail Golkovski ◽  
Dossymkhan Mussakhanov ◽  
Zhakyp Karipbayev ◽  
...  

The variety of applications of yttrium-aluminum garnet (YAG)-based luminescent materials and the morphology necessary for these purposes required the development of many technologies for their synthesis. All synthesis technologies used are complex. The structural phase of yttrium-aluminum garnet is formed with any technology, at temperatures exceeding 1,500 °C. The starting materials for the synthesis are metal oxides of aluminum, yttrium and other oxides for activation and modification. It seems possible to use hard radiation to form a new phase. Radiation synthesis of ceramics is realized in less than 1 s, without the use of any additives and influences. The synthesis was carried out at the electron accelerator of the Institute of Nuclear Physics (Novosibirsk). In this work, we studied the spectral-kinetic and quantitative characteristics of luminescence for the first time obtained by the method of radiation synthesis of ceramic samples of yttrium-aluminum garnet doped with cerium with statistical processing of their values. The dependences of the reproducibility of the spectral characteristics of the luminescence of the samples on the preliminary preparation of the charge for synthesis have been investigated. Several cycles of luminophore brightness studies have been performed. It is shown that the obtained ceramics based on yttrium-aluminum garnet doped with cerium possesses the required spectral-kinetic properties, and the efficiency of conversion of the chip radiation into luminescence is achieved, which is comparable to that available in commercial phosphors. The maximum measured values of the position of the bands are from 553.5 to 559.6 nm. Brightness values range from 4,720 to 1,960 cd/m2. It was found that the main reason for the scatter in the characteristics of the luminescent properties of ceramics of yttrium-aluminum garnet, activated by cerium obtained by radiation assisted synthesis is the high rate of synthesis and, especially, the high rate of cooling of the samples.


Author(s):  
M. Hibino ◽  
K. Irie ◽  
R. Autrata ◽  
P. schauer

Although powdered phosphor screens are usually used for scintillators of STEM, it has been found that the phosphor screen of appropriate thickness should be used depending on the accelerating voltage, in order to keep high detective quantum efficiency. 1 It has been also found that the variation in sensitivity, due to granularity of phosphor screens, makes the measurement of fine electron probe difficult and that the sensitivity reduces with electron irradiation specially at high voltages.In order to find out a preferable scintillator for STEM, single crystals of YAG (yttrium aluminum garnet), which are used for detecting secondary and backscattered electrons in SEM were investigated and compared with powdered phosphor screens, at the accelerating voltages of 100kV and 1 MV. A conventional electron detection system, consisting of scintillator, light guide and PMT (Hamamatsu Photonics R268) was used for measurements. Scintillators used are YAG single crystals of 1.0 to 3.2mm thicknesses (with surfaces matted for good interface to the light guide) and of 0.8mm thickness (with polished surface), and powdered P-46 phosphor screens of 0.07mm and 1.0mm thicknesses for 100kV and 1MV, respectively. Surfaces on electron-incidence side of all scintillators are coated with reflecting layers.


Author(s):  
Shao-Ju Shih ◽  
Lewi Peter Richardo ◽  
Kevin Indrawan Sucipto ◽  
Zhi-Meng Wang

1990 ◽  
Vol 209 ◽  
Author(s):  
R.S. Hay ◽  
L.E. Matson

ABSTRACTGeometric criteria for low interface energy and interface structure were tested for the cubic-rhombohedral system YAG/alumina. Orientation relationships near (111){110}a // (112){110}y and facets on (111)a(112)y were observed in both sol-gel derived composites and directionally solidified eutectic composites. The ΣYAG=12 near-CSL of 2{111}, {110}, {112} was inferred to be the preferred structural unit. Dislocations with b=1/3{111}a and b=1/2{110}a were observed and inferred to accomodate deviation from the structural unit, respectively. The {110}a,y direction met some of the criteria for an invariant line. Although the OR was explained by geometric criteria it would have been difficult to predict it with such criteria


1986 ◽  
Vol 45 (5) ◽  
pp. 1191-1194
Author(s):  
T. F. Veremeichik ◽  
I. N. Kalinkina

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