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arXiv · 2310.16529

Design considerations for the optimization of {\lambda}-SQUIDs

Constantin Schuster·Sebastian Kempf
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Abstract

Cryogenic microcalorimeters are key tools for high-resolution X-ray spectroscopy due to their excellent energy resolution and quantum efficiency close to 100%. Multiple types of microcalorimeters exist, some of which have already proven outstanding performance. Nevertheless, they can't yet compete with cutting-edge grating or crystal spectrometers. For this reason, novel microcalorimeter concepts are continuously developed. One such concept is based on the strong temperature dependence of the magnetic penetration depth of a superconductor operated close to its transition temperature. This so-called ${\lambda}$-SQUID provides an in-situ tunable gain and promises to reach sub-eV energy resolution. Here, we present some design considerations with respect to the optimization of such a detector that are derived by analytic means. We particularly show that for this detector concept the heat capacity of the sensor should match the heat capacity of the absorber.

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Constantin Schuster, Sebastian Kempf. 2023-10-25. Design considerations for the optimization of {\lambda}-SQUIDs. https://arxiv.org/abs/2310.16529

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