https://doi.org/10.1140/epjc/s10052-015-3572-9
Regular Article - Experimental Physics
A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2
1
Max-Planck-Institut für Physik, 80805, Munich, Germany
2
Physik-Department, Technische Universität München, 85748, Garching, Germany
3
CIUC, Departamento de Fisica, Universidade de Coimbra, 3004 516, Coimbra, Portugal
4
INFN, Laboratori Nazionali del Gran Sasso, 67010, Assergi, Italy
5
Walther-Meißner-Institut für Tieftemperaturforschung, 85748, Garching, Germany
6
Physikalisches Institut, Eberhard-Karls-Universität Tübingen, 72076, Tübingen, Germany
7
Department of Physics, University of Oxford, Oxford, OX1 3RH, UK
8
Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, 1050, Wien, Austria
9
Atominstitut, Vienna University of Technology, 1020, Wien, Austria
10
Albert Einstein Center for Fundamental Physics, University of Bern, 3012, Bern, Switzerland
* e-mail: strauss@mpp.mpg.de
Received:
8
October
2014
Accepted:
20
July
2015
Published online:
31
July
2015
The cryogenic dark matter experiment CRESST-II aims at the direct detection of WIMPs via elastic scattering off nuclei in scintillating CaWO
crystals. We present a new, highly improved, detector design installed in the current run of CRESST-II Phase 2 with an efficient active rejection of surface-alpha backgrounds. Using CaWO sticks instead of metal clamps to hold the target crystal, a detector housing with fully-scintillating inner surface could be realized. The presented detector (TUM40) provides an excellent threshold of 
keV and a resolution of 
keV (at 2.60 keV). With significantly reduced background levels, TUM40 sets stringent limits on the spin-independent WIMP-nucleon scattering cross section and probes a new region of parameter space for WIMP masses below 3 GeV/c
. In this paper, we discuss the novel detector design and the surface-alpha event rejection in detail.
© The Author(s), 2015
