Bonn 2010 – scientific programme

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T: Fachverband Teilchenphysik

T 107: Niederenergie-Neutrinophysik und Suche nach dunkler Materie I

T 107.8: Talk

Monday, March 15, 2010, 18:40–18:55, HG XI

Czochralski growth of scintillating CaWO₄ crystals for cryogenic dark matter search and Monte-Carlo simulations for optimal crystal shape — •Moritz von Sivers, Christian Ciemniak, Chiara Coppi, Franz von Feilitzsch, Christian Isaila, Jean-Come Lanfranchi, Sebastian Pfister, Walter Potzel, Sabine Roth, and Raimund Strauss — Technische Universität München, Physik-Department, E15

To ensure the availability of inorganic scintillators that meet the requirements of cryogenic dark matter searches like the CRESST and future EURECA experiments, CaWO₄ crystals are being produced with a Czochralski furnace at the crystal laboratory of the Technische Universität München (TUM) in Garching. In this setup crystals of different shapes with a diameter up to 35mm and a length up to 150mm have been produced. An overview of the crystal-growth process and results of measurements of the crystals’ light yield and radiopurity are presented. The high refractive index of CaWO₄ (n≈1.93) potentially leaves a large fraction of scintillation photons trapped inside the cylindrical crystals that are currently used in CRESST. The talk will give the results of a MC simulation based on GEANT4, to study the amount of trapped light and the effects of differently shaped crystals on the light collection in a CRESST-like detector module.
This work has been supported by funds of the Deutsche Forschungsgemeinschaft DFG (Transregio 27: Neutrinos and Beyond), the Excellence Cluster (Origin and Structure of the Universe) and the Maier-Leibnitz-Laboratorium (Garching).