Quenching factor measurement for by neutron scattering

The CaWO 4 detectors of CRESST are able to distinguish electron recoils as induced by ionizing radiation from nuclear recoils as expected from heavy dark matter particles (WIMPs) thanks to the coincident measurement of the phonon and scintillation light signals produced in an event. For a detailed understanding of the detector response to nuclear recoils, especially the light yield or quenching factor, measurements with different neutron sources have been performed. Standard neutron sources such as Am–Be yield some information but a better separation of the signals from the different nuclei can be obtained by a monoenergetic pulsed neutron source when additionally measuring the scattered neutrons. Such an experiment has been set up at the tandem accelerator at the Maier–Leibnitz Laboratory in Garching. Results from a first series of measurements at room temperature will be presented as well as the status of the experiment towards cryogenic measurements.