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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: POSTER: Biological Systems + New Materials
CPP 20.10: Poster
Mittwoch, 28. März 2007, 16:00–18:30, Poster B
Structure of polymer coatings established for advanced quantum efficiency of photomultiplier tubes — •V. Körstgens1, C.-C. Hsu2, D. Paneque3, E. Lorenz2, and P. Müller-Buschbaum1 — 1TU München, Physikdepartment E13, James-Franck-Str. 1, D-85748 Garching — 2Max-Planck-Institut für Physik, Föhringer Ring 6, D-80508 München — 3Stanford Linear Accelerator Center, Menlo Park, CA
Coatings consisting of a polyacrylate and para-terphenyl as wavelength shifter are established from solutions in chlorinated organic solvents via a spin-coating process. The coatings are milky in appearance and the coated photomultiplier tubes show an advanced quantum efficiency. Preparation conditions were varied with controlled humidity and the exposition of the sample to a flow of humid nitrogen while spin-coating and evaporation of the solvent. Optical microscopy revealed structures originated from crystallization of para-terphenyl and a superposed porous structure of the polymer matrix. Surface structures established on flat substrates under same conditions were also investigated by atomic force microscopy (AFM). The origin of the obtained structures is discussed in context to well-known structures referred to as breath figures. The relation between the surface structures of the polymer coating and the observed advanced quantum efficiency of photomultiplier tubes is addressed.