Abstract |
The CRESST experiment, aiming at the direct detection of WIMPs via nuclear recoils,
is currently using scintillating CaWO4 crystals. The WIMP–nucleus cross section for
elastic scattering as well as the scintillation efficiency differ considerably for recoils
from Ca, W and O in these crystals. Therefore a discriminating detector calibration
is essential in order to improve WIMP parameter claims. At the tandem accelerator
of the Maier-Leibnitz-Laboratory (MLL) in Garching, Germany, a neutron scattering
facility is operated for the determination of the individual quenching factors (QF) in
the bulk of a CaWO4 crystal to better understand the detector response to neutron
background and a possible WIMP signal. First measurements at room temperature
reveal QF(O) = 7.8 ± 0.3% (recoil energy 1.0–2.2 MeV), QF(Ca) = 6.3 ± 1.6% (recoil
energy 0.4–1 MeV), QF(W) < 3.0% (2s, recoil energy 0.1 MeV). |
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