TY  - THES
AU  - Karim, Kamran Said
TI  - Herstellung polykristalliner Szintillatoren für die Positronen-Emissions-Tomographie (PET)
VL  - 55
SN  - 1866-1793
PB  - Univ. Bochum
VL  - Dr. (Univ.)
CY  - Jülich
M1  - PreJuSER-10152
SN  - 978-3-89336-610-1
T2  - Schriften des Forschungszentrums Jülich : Energie & Umwelt / Energy & Environment
SP  - VI, 154 S.
PY  - 2010
N1  - Record converted from VDB: 12.11.2012
N1  - Univ. Bochum, Diss., 2010
AB  - Transparent ceramics are becoming more and more important for two new types of
AB  - applications. On the one hand in cases where high mechanical and thermal demands in combination with optical properties are required, on the other hand where the optical properties of transparent materials like glass are not sufficient e.g. in positronemission-tomography (PET) diagnostics. Most state of the art PET-scanners are using high-priced single crystals as scintillator material. The technological challenge is to replace single crystal by cost-efficient transparent ceramics. Producing transparent ceramics is ordered in synthesis of the powders and in manufacturing of these into transparent ceramics.
AB  - The aim of this work was to synthesize single phase yttrium-alumina-and Luthetiumalumina- garnet (YAG, LuAG) powders partially doped with neodymium or
AB  - praseodymium by four different synthesis routes (Pechini-synthesis, sol-gel-route, coprecipitation and solid state reactions). Additionally industrial LuAG and LuPO4
AB  - powders were characterized and manufactured. The powders were processed as submicron- and nanopowders. 
AB  - 
AB  - Newly produced single-phase powders were homgenized with additions of sintering
AB  - additives like tetraethyl orthosilicate (TEOS) and binders like polyvinyl alcohol (PVA).
AB  - Moulding the powders were carried out by unaxial pressing, cold isostatic pressing
AB  - and in individual cases also by slip casting. The achieved green densities were in a range of 25-42 %. Examination of calcination behaviour leads to a calcination
AB  - temperature of 1000 °C with 2 hours dwell time in air atmosphere.
AB  - Only solid state reactions resulted into transparent YAG, YAG:Pr, LuAG, LuAG:Pr
AB  - ceramics. Solid state reactions of nanopowders resulted in heterogeneously
AB  - transparent samples. Ceramics made by powders of other synthetic routes gave nontransparent ceramics due to porosity and additional phases. Transmission measurements of the manufactured transparent ceramics showed in classical one step sintering and two step sintering program significant lower transmission than respectitive single crystals but similar transmission compared to ceramics reported in literature.
LB  - PUB:(DE-HGF)11 ; PUB:(DE-HGF)3
UR  - https://juser.fz-juelich.de/record/10152
ER  -