SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 66: Cryogenic Detectors

TT 66.2: Talk

Friday, March 31, 2023, 10:00–10:15, HSZ 304

Novel concept for a superconducting microcalorimeter with tunable gain — •Constantin Schuster, Gabriel Jülg, and Sebastian Kempf — Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany

Cryogenic microcalorimeters such as metallic magnetic calorimeters (MMC) or transition edge sensors (TES) are becoming a mature technology and are hence presently used in various applications requiring an excellent energy resolution. They rely on transducing the temperature rise upon the absorption of an energetic particle into a change of magnetic flux (MMC) or electrical current (TES) which is measured using a SQUID. Despite the overall great success, it turns out that the resolving power still lacks behind the fundamental limit set by fluctuations of thermal energy among different degrees of freedom of the detector. Against this background, we present a novel detector concept which may help to improve the energy resolution. It is based on the strong temperature dependence of the magnetic penetration depth of a superconductor close to its critical temperature. By embedding a properly chosen superconductor directly into the SQUID loop and using a special input circuit configuration, a change in temperature is transduced into a change in magnetic flux threading the SQUID loop. Moreover, it turns out that the temperature to flux transfer coefficient can be tuned in-situ. We present our detector concept and gauge the possible performance and energy resolution of this novel detector concept by discussing simulating results and and first experimental data.