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F o C al inspirace odjinud

F o C al inspirace odjinud. Libor Š koda. Workshop EJČF 2013. Nanocomposite scintillators with polymer matrix. Scintillating materials - production problems (single crystals growth, preparation in ceramic form, …) Composite materials

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F o C al inspirace odjinud

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  1. FoCalinspirace odjinud Libor Škoda Workshop EJČF 2013

  2. Nanocomposite scintillators with polymer matrix

  3. Scintillating materials • - production problems (single crystals growth, preparation in ceramic form, …) • Composite materials • scintillating (nano)material incorporated inside the polymer matrix: • versatility • wide application field of the combined materials • easiness of preparation • various compounds as a matrix such as porous silica, polymethylmethacrylate, tetraethoxysilan, epoxy matrices etc.

  4. KJCH FJFI: • nano-scale powder materials (nickel, zinc, yttrium, aluminum and cobalt oxides, zinc peroxide and hydroxide, yttrium and lutetium aluminum garnets and cobalt(II) aluminate) • precipitation from aqueous solution induced by accelerated electrons, gamma, UV radiation • interesting characteristics - high chemical purity, high specific surface area and narrow distribution of particle size • Zinc oxide: • wide direct band gap (~ 3.3 eV) • high exciton and biexciton energies (60 meV or 15 meV) • very short luminiscence lifetime under 1 ns • strong room temperature luminiscence • doping with various ions - affects both intesity and lifetime of the luminiscence

  5. ZnO:Ga(La)/polymer nanocomposite: • nanosized crystalline ZnO (gallium nitrate or lanthanum doped) powder (particle size ~ 100 nm) - very intensive excitonic luminescence under X-ray excitation (40 kV, 15 mA), with distinct maximum at ~ 395 nm • homogenous dispersion in the solution of urethane dimethacrylate monomers • fast UV-induced polymerization (-> optically transparent polyurethane matrix with embedded nanopowder) • most promising and interesting powders were compared to Bismuth Germanate (BGO)

  6. Radioluminescence spectra of various ZnO:Ga(La) powders and powders incorporated into the polymer matrix

  7. Conclusion: • due to heat treatment and reduction in the reduction atmosphere: • - no emission in the visible region of the spectrum • - no noise from unwanted impurities or defects • maximum of the intensity of the luminescent peak - 392 nm • gallium doped sample shows significantly higher intensity of the luminescence • intensity of all of the nanocomposites is significantly lower than the appropriate powders • this nanocomposites show exciton luminescent but large amount of the photons is absorbed by the polymer

  8. Možnostivyužití: • jednodušší zpracování tvaru a povrchu - připojení opt. vláken ke scintilátoru- efektivnější sběr signálu (?) • přímé odlévání do formy na W-desce (?) • . . .?

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