Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.66: Poster
Montag, 31. März 2014, 15:00–19:00, P2
Development of dc-SQUIDs for the readout of metallic magnetic calorimeters — •A. Ferring, S. Kempf, M. Wegner, A. Fleischmann, L. Gastaldo, and C. Enss — Kirchhoff-Institute for Physics, Heidelberg University.
The very large bandwidth, the quantum limited noise performance, as well as the compatibility with very low operation temperatures make superconducting quantum interference devices (SQUIDs) the devices of choice for the readout of low temperature microcalorimeters such as metallic magnetic calorimeters (MMCs). For many MMC, low inductance current sensing SQUIDs are used to either directly measure the detector output signal or to act as an ultra low noise amplifier in a multistage SQUID configuration. Due to the desire for devices that are optimized for the readout of state-of-the-art MMCs, we have recently started the development of low-Tc current sensing dc-SQUIDs employing an in-situ sputtered Nb/Al-AlOx/Nb trilayer.
We discuss our various dc-SQUID designs as well as the properties of produced prototype SQUIDs. In particular, we compare SQUIDs made by three different fabrication processes that are based on selective Niobium etching which is optionally combined with chemical anodization. We investigate the noise performance of our devices with respect to the absolute value and the temperature dependence of the white noise level. Furthermore, we study the presence of an 1/f-like noise contribution and its temperature dependent behaviour. Finally, we experimentally show that state-of-the-art MMCs can successfully be read out by our SQUIDs.