Development of a combined photon and phonon detector for rare-event experiments

Scintillating crystals in cryogenic experiments searching for a direct interaction of dark matter particles and for the neutrinoless double beta decay, as in AMoRE or LUMINEU, allow for an efficient active background reduction due to particle mass discrimination. This is achieved by the simultaneous measurements of heat and light generated by the interaction of a particle in the scintillating crystal. We are developing phonon and large area photon detectors based on metallic magnetic calorimeters (MMCs) to readout both types of excitations. We will present the design for a photon detector P1 with an expected energy resolution of ΔE_FWHM < 5 eV and a signal rise time of τ < 50 μs and discuss its fabrication and first experimental results. Furthermore we will present the design and the fabrication of the integrated photon and phonon detector P2, with a light detector inspired by P1 and three phonon sensors with ΔE_FWHM < 100 eV and τ < 200 μs on the same chip. This allows for a very efficient readout, a minimum of material for support structures and further background reduction by position sensitive phonon signals.