Metallic magnetic calorimeters (MMCs) are low-temperature particle detectors that are currently strongly advancing the state-of-the-art in single particle detection. They are typically operated at temperatures T< 100mK and imposingly combine a fast signal rise time, an excellent energy resolution, a large energy dynamic range, a high quantum efficiency as well as an almost ideal linear detector response. For this reason, single-channel detectors and medium-size MMC arrays appear to be a key technology for a variety of applications requiring high-resolution and wideband energy-dispersive single-particle detectors. Famous examples are the investigation of highly-charged ions, the search for the neutrinoless double beta decay, the investigation of the electron neutrino mass, nuclear safeguards or mass spectrometry. But in spite of this big success, it can be anticipated that future experiments demand for massive multi-channel detector systems to facilitate imaging or position-sensitive measurements or to increase the overall statistics. To realize such systems, microfabrication techniques that allow to reliably manufacture thousands of virtually identical detectors as well as suitable readout techniques need to be established.
In this talk, we will motivate the anticipated need for MMC based multi-channel detector systems by highlighting several MMC based applications. We will then discuss the state-of-the-art in the microfabrication of MMCs which we successfully established during recent years and that allows to manufacture such large-scale detector arrays. Afterwards, we will put special emphasis on the development of SQUID based readout techniques, both for single-channel detectors as well as large-scale arrays.
