SQUID-based superconducting microcalorimeter with in-situ tunable gain

TL;DR

This paper introduces a novel SQUID-based superconducting microcalorimeter with in-situ tunable gain, leveraging temperature-dependent magnetic properties to achieve potentially superior energy resolution for X-ray spectroscopy.

Contribution

The paper presents an innovative microcalorimeter design that uses in-situ tunable gain based on superconducting properties, improving upon existing energy resolution limitations.

Findings

Prototype shows no hysteresis effects.

Predicted energy resolution around 300 meV.

Potential for competitive performance in X-ray spectroscopy.

Abstract

Cryogenic microcalorimeters are outstanding tools for X-ray spectroscopy due to their unique combination of excellent energy resolution and close to 100% detection efficiency. While well-established microcalorimeter concepts have already proven impressive performance, their energy resolution has yet to improve to be competitive with cutting-edge wavelength-dispersive grating or crystal spectrometers. We hence present an innovative SQUID-based superconducting microcalorimeter with an in-situ tunable gain as alternative concept that is based on the strong temperature dependence of the magnetic penetration depth of a superconductor operated close to its critical temperature. Measurements using a prototype device show no sign for any hysteresis effects that often spoil the performance of superconducting microcalorimeters. Moreover, our predictions of the achievable energy resolution show that a competitive energy resolution O(300meV) with a suitable combination of absorber and sensor material should be easily possible.