A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2

R. Strauss; G. Angloher; A. Bento; C. Bucci; L. Canonica; A. Erb; F. von Feilitzsch; N. Ferreiro; P. Gorla; A. Gütlein; D. Hauff; J. Jochum; M. Kiefer; H. Kluck; H. Kraus; J.-C. Lanfranchi; J. Loebell; A. Münster; F. Petricca; W. Potzel; F. Pröbst; F. Reindl; S. Roth; K. Rottler; C. Sailer; K. Schäffner; J. Schieck; S. Scholl; S. Schönert; W. Seidel; M. von Sivers; M. Stanger; L. Stodolsky; C. Strandhagen; A. Tanzke; M. Uffinger; A. Ulrich; I. Usherov; S. Wawoczny; M. Willers; M. Wüstrich; A. Zöller

doi:10.1140/epjc/s10052-015-3572-9

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2015) 75: 352
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

R. Strauss¹^,2^*, G. Angloher¹, A. Bento³, C. Bucci⁴, L. Canonica⁴, A. Erb²^,5, F. von Feilitzsch², N. Ferreiro¹, P. Gorla⁴, A. Gütlein², D. Hauff¹, J. Jochum⁶, M. Kiefer¹, H. Kluck⁸^,9, H. Kraus⁷, J.-C. Lanfranchi², J. Loebell⁶, A. Münster², F. Petricca¹, W. Potzel², F. Pröbst¹, F. Reindl¹, S. Roth², K. Rottler⁶, C. Sailer⁶, K. Schäffner⁴, J. Schieck⁸, S. Scholl⁶, S. Schönert², W. Seidel¹, M. von Sivers², M. Stanger², L. Stodolsky¹, C. Strandhagen⁶, A. Tanzke¹, M. Uffinger⁶, A. Ulrich², I. Usherov⁶, S. Wawoczny², M. Willers², M. Wüstrich¹ and A. Zöller²

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

Abstract

The cryogenic dark matter experiment CRESST-II aims at the direct detection of WIMPs via elastic scattering off nuclei in scintillating CaWO $$_4$$ 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 $$_4$$ 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 ${\sim }0.60$ keV and a resolution of $\sigma \,{\approx }\,0.090$ 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 $$^2$$ . In this paper, we discuss the novel detector design and the surface-alpha event rejection in detail.