Regensburg 2007 – wissenschaftliches Programm

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ST: Fachverband Strahlen- und Medizinphysik

ST 5: Strahlendetektoren

ST 5.2: Vortrag

Dienstag, 27. März 2007, 09:45–10:00, Ch 12.0.16

Photostimulated luminescence sensitivity enhancement of the storage phosphor CsBr:Eu²⁺ by thermal treatment in oxygen — •Jörg Zimmermann, Sabine Hesse, and Heinz von Seggern — Institute of Materials Science, Electronic Materials Division, Petersenstrasse 23, 64287 Darmstadt, Germany

Nowadays image plates (IP) are widely used for 2D detection of x-rays in medicine and materials research. Commercial IPs consist of a powder of the storage phosphor BaFBr:Eu²⁺ mixed with a polymer binder on a polymer substrate. The spatial resolution of those plates is limited by light scattering introduced by the difference of refractive index of binder and phosphor grains. For IPs with higher spatial resolution and comparable photostimulated luminescence (PSL) sensitivity the X-ray storage phosphor CsBr:Eu²⁺ is a promising material since it can be grown spicular on a glass substrate using evaporation techniques. The higher resolution of those NIPs (needle image plates) thereby is achieved by a light guiding effect resulting from the thin needles exhibiting diameters in the ten-micrometer scale. It will be demonstrated that the introduction of oxygen enhances the sensitivity of this storage phosphor. The influence of thermal treatment in oxygen containing atmosphere is investigated by means of various spectroscopic methods. A possible mechanism for the influence of oxygen in CsBr:Eu²⁺ on its optical properties will be discussed.