Cryogenic particle detection based on magnetic microcalorimeters for rare event searches

Magnetic microcalorimeters (MMCs) have become essential components of many science applications requiring high-resolution detection. MMCs serve as sensitive thermometers that measure the temperature increase in a thermal calorimetric detection system at mK temperatures. The MMC technology utilizes a superconducting circuit and electronics together with a magnetic sensor material of a gold or silver alloy doped with a small concentration of erbium. The metallic sensor material ensures the fast thermalization of the sensor itself, which is a critical parameter for achieving good energy resolution and timing resolution in cryogenic particle detection applications. A detector system consisting of a crystal absorber and an MMC is a sensitive detector with a wide dynamic energy range and good energy linearity. Moreover, light detectors based on MMC readouts are applicable to heat and light detection when using a scintillating crystal as an absorber. In this review, we present the methods by which a detector setup is configured with MMCs for rare event search experiments. The design concerns based on the thermal component models are presented for various rare event search applications of double beta decay experiments and dark matter searches.