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TT: Fachverband Tiefe Temperaturen
TT 31: Superconducting Electronics and Cryogenics: Poster Session
TT 31.11: Poster
Thursday, September 8, 2022, 15:00–18:00, P1
Fabrication process for Nb/Al-AlOx/Nb Josephson tunnel junction based SQUIDs for magnetic microcalorimeter readout — •Martin Neidig, Paul Kahrmann, and Sebastian Kempf — Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany
Magnetic microcalorimeters (MMCs) are cryogenic particle detectors providing an excellent energy resolution, very fast signal rise time, an almost ideal linear detector response and a large dynamic range. These properties combined with a maturing fabrication process motivate the implementation of large MMC based detector arrays which poses the challenge of developing a suitable readout method. Small-scale arrays are typically readout using single-channel dc-SQUIDs with individual wiring, while large-scale arrays require a multiplexed readout scheme. One such multiplexing scheme is the microwave SQUID multiplexer which allows for the readout of hundreds of detectors via a common feedline. The realization of either readout method requires the use of SQUIDs and therefore a reliable fabrication process for high quality Josephson junctions.
For this purpose we established a fabrication process for Nb/Al-AlOx/Nb based window-type Josephson tunnel junctions. Within this contribution, we outline the present status of our fabrication technology and, moreover, we discuss the performance of the fabricated junctions and results of our prototype dc-SQUIDs, which are presently used for several MMC based experiments.