[en] CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) uses CaWO_4 single crystals as targets for the direct search for dark matter particles. Since several years these CaWO_4 crystals are grown at the Technische Universitaet Muenchen. Thereby, commercially available CaCO_3 and WO_3 powders are used for the synthesis of CaWO_4 powder. For the experiment low intrinsic contaminations of the crystals play a crucial role. In order to improve the radiopurity of the crystals it is necessary to reduce potential sources for radioactive backgrounds such as U and Th. In this poster we will present our studies of the chemical purification of the CaCO_3 and CaWO_4 powders.
Journal
Verhandlungen der Deutschen Physikalischen Gesellschaft; ISSN 0420-0195; 
; CODEN VDPEAZ; (Hamburg 2016 issue); [1 p.]
; CODEN VDPEAZ; (Hamburg 2016 issue); [1 p.]
[en] In the scope of the dark matter search experiment CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) the Technische Universitaet Muenchen (TUM) produces high purity CaWO_4 single crystals. CRESST uses these scintillating crystals as targets to directly search for dark matter particles. An important factor for the event detection and discrimination is the light-output of the crystals. This light-output shows a crystal dependent non-linear behaviour at low energies, which affects the discrimination capabilities of the detector. To investigate this behaviour and the dependency on the growth parameters, a Compton scattering experiment is conducted. The experimental setup and first results are presented.
Journal
Verhandlungen der Deutschen Physikalischen Gesellschaft; ISSN 0420-0195; ; CODEN VDPEAZ; (Hamburg 2016 issue); [1 p.]
; CODEN VDPEAZ; (Hamburg 2016 issue); [1 p.]