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TT: Fachverband Tiefe Temperaturen
TT 60: Cryogenic Detectors and Sensors, Refrigeration and Thermometry
TT 60.3: Talk
Wednesday, March 20, 2024, 16:30–16:45, H 3025
Optimizing microwave SQUID multiplexers for magnetic microcalorimeter readout — •Martin Neidig1, Constantin Schuster1, Lena Hauswald1, Mathias Wegner2,1, Stefan Wünsch1, and Sebastian Kempf1,2 — 1Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology, Germany — 2Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Germany
Magnetic microcalorimeters (MMCs) are cryogenic particle detectors which have achieved a high level of maturity. Thanks to reliable microfabrication processes, large-scale MMC arrays consisting of hundreds or even thousands of detectors are meanwhile feasible, presenting the challenge of developing a suitable multiplexing technique. In this respect, microwave SQUID multiplexing is the current state of the art. Here, the individual detector signals can be frequency-encoded by inductively coupling each detector to a non-hysteretic rf-SQUID which in turn is inductively coupled to microwave resonator with unique resonance frequency. This enables the simultaneous readout of hundreds of detectors using a single transmission line, typically utilizing a bandwidth of 4 to 8 GHz. In this contribution. we discuss the advantages of operating microwave SQUID multiplexers at frequencies above 8 GHz, showcasing increased multiplexing factor, improved readout sensitivity and reduced device dimensions. Additionally, we present first measurements aiming to prove the feasibility of such devices. Finally, we address challenges associated with connecting a microwave SQUID multiplexer to an actual detector chip.
Keywords: microwave SQUID multiplexers; magnetic microcalorimeters; rf-SQUIDs