Göttingen 2012 – scientific programme

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T: Fachverband Teilchenphysik

T 108: Niederenergie-Neutrinophysik/Suche nach Dunkler Materie 3

T 108.2: Talk

Tuesday, February 28, 2012, 17:05–17:20, ZHG 102

In Situ Determination of Quenching Factors in Cresst-II — •Andreas Zöller¹, Christian Ciemniak¹, Franz von Feilitzsch¹, Josef Jochum², Jean-Come Lanfranchi¹, Walter Potzel¹, Franz Pröbst³, Stefan Schönert¹, Stephan Scholl^2,3, Raimund Strauss¹, and Stephan Wawoczny¹ — ¹Technische Universität München, Physik Department E15 — ²Eberhard Karls Universität Tübingen — ³Max Planck Institut für Physik, München

The CRESST-II experiment is searching for WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off nuclei in scintillating CaWO₄ single crystals at low temperatures. Each particle interaction in CaWO₄ produces a phonon as well as a light signal. The ratio between the recorded light and phonon signal - the Quenching Factor (QF) - is a crucial parameter to discriminate very efficiently between electron recoils from radioactive e/γ background and nuclear recoils, e.g. WIMP events. Moreover, to some extent, the different types of recoiling nuclei (O, Ca, W) can be distinguished, if the QF’s are known accurately enough. The QF cannot only be extracted from dedicated experiments but also from calibration data, gathered with an AmBe-source placed inside and outside the neutron shielding of CRESST-II. In this talk we present a method to determine the QFs of CaWO₄ in situ from these calibration data. Furthermore, first results will be shown, discussed and compared to other measurements.

This work has been supported by the cluster of excellence “Origin and Structure of the Universe”, the SFB-TR27 and the Maier-Leibnitz-Laboratorium.