Author/Authors :
Angloher، نويسنده , , G. R. Bauer ، نويسنده , , M. and Bavykina، نويسنده , , I. and Bento، نويسنده , , A. and Brown، نويسنده , , A. and Bucci، نويسنده , , C. and Ciemniak، نويسنده , , C. and Coppi، نويسنده , , C. and Deuter، نويسنده , , G. and von Feilitzsch، نويسنده , , F. and Hauff، نويسنده , , D. and Henry، نويسنده , , S. and Huff، نويسنده , , P. and Imber، نويسنده , , J. David Ingleby، نويسنده , , S. and Isaila، نويسنده , , C. and Jochum، نويسنده , , J. and Kiefer، نويسنده , , M. and Kimmerle، نويسنده , , M. and Kraus، نويسنده , , H. and Lanfranchi، نويسنده , , J.-C. and Lang، نويسنده , , R.F. and Majorovits، نويسنده , , M. F. B. A. Malek، نويسنده , , M. and McGowan، نويسنده , , R. and Mikhailik، نويسنده , , V.B. and Pantic، نويسنده , , E. and Petricca، نويسنده , , F. and Pfister، نويسنده , , S. and Potzel، نويسنده , , W. and Prِbst، نويسنده , , F. and Rau، نويسنده , , W. and Roth، نويسنده , , S. and Rottler، نويسنده , , K. and Sailer، نويسنده , , C. and Schنffner، نويسنده , , K. and Schmaler، نويسنده , , J. and Scholl، نويسنده , , S. and Seidel، نويسنده , , W. and Stodolsky، نويسنده , , L. A. Tolhurst، نويسنده , , A.J.B. and Usherov، نويسنده , , I. and Westphal، نويسنده , , W.، نويسنده ,
Abstract :
The CRESST cryogenic direct dark matter search at Gran Sasso, searching for WIMPs via nuclear recoil, has been upgraded to CRESST-II by several changes and improvements. The upgrade includes a new detector support structure capable of accommodating 33 modules, the associated multichannel readout with 66 SQUID channels, a neutron shield, a calibration source lift, and the installation of a muon veto. We present the results of a commissioning run carried out in 2007.
sic element of CRESST-II is a detector module consisting of a large ( ∼ 300 g ) CaWO 4 crystal and a very sensitive smaller ( ∼ 2 g ) light detector to detect the scintillation light from the CaWO 4 . The large crystal gives an accurate total energy measurement. The light detector permits a determination of the light yield for an event, allowing an effective separation of nuclear recoils from electron–photon backgrounds. Furthermore, information from light-quenching factor studies allows the definition of a region of the energy-light yield plane which corresponds to tungsten recoils. A neutron test is reported which supports the principle of using the light yield to identify the recoiling nucleus.
btained with two detector modules for a total exposure of 48 kg-days are presented. Judging by the rate of events in the “all nuclear recoils” acceptance region the apparatus shows a factor ∼10 improvement with respect to previous results, which we attribute principally to the presence of the neutron shield. In the “tungsten recoils” acceptance region three events are found, corresponding to a rate of 0.063 per kg-day. Standard assumptions on the dark matter flux, coherent or spin independent interactions, then yield a limit for WIMP-nucleon scattering of 4.8 × 10 - 7 pb , at M WIMP ∼ 50 GeV .
