Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Cryogenic Detectors and Cryotechnique
TT 17.3: Vortrag
Mittwoch, 7. September 2022, 10:00–10:15, H22
Low-noise, impedance matched current-sensing dc-SQUIDs for magnetic microcalorimeter readout — •Fabienne Bauer1,2, Christian Enss1, and Sebastian Kempf1,2 — 1Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg — 2Institute of Micro- and Nanoelectronics Systems, Karlsruhe Institute of Technology, Hertzstraße 16, 76187 Karlsruhe
Direct-current superconducting quantum interference devices (dc-SQUIDs) are the devices of choice for reading out low-impedance cryogenic particle detectors such as magnetic microcalorimeters (MMCs). MMCs use a paramagnetic or superconducting temperature sensor, placed in a weak magnetic field and inductively coupled to a superconducting pickup coil, to convert deposited energy into a change of magnetic flux threading the pickup coil. The latter is sensed using a low-noise SQUID. To maximize sensitivity and hence energy resolving power, impedance matching between SQUID and pickup coil as well as a SQUID white noise level close to the quantum limit are crucial. As current-sensing SQUIDs with input inductances between 1 nH and 10 nH and suited for mK-operation temperatures are rarely or not at all commercially available, custom SQUIDs for MMC readout must be developed. In this context, we discuss design and performance of three current-sensing dc-SQUIDs impedance matched to MMCs that are foreseen for neutrino mass investigation, X-ray spectroscopy and mass spectrometry, respectively. To achieve low-noise performance, the SQUIDs rely on the use of cross-type Josephson junctions to minimize junction capacitance and hence readout noise.