Intermediate states of superconducting thermometers for x-ray microcalorimeters

TL;DR

This study uses Low Temperature Scanning Synchrotron Microscopy to visualize phase separation in superconducting thermometers near the transition temperature, enhancing understanding of their intermediate states for x-ray calorimetry.

Contribution

It introduces an imaging technique to directly observe phase separation in superconducting thermometers, providing new insights into their intermediate states at ~100mK.

Findings

Normal-superconducting phase separation occurs in intermediate states.

LTSSM effectively visualizes phase boundaries in superconducting sensors.

Understanding these states improves the design of sensitive x-ray thermometers.

Abstract

Intermediate states near normal-superconducting transition at ~100mK, important for a sensitive thermometer in x-ray calorimetry, have been studied by an imaging technique based on Low Temperature Scanning Synchrotron Microscopy (LTSSM). In conjunction with iridium superconducting transition-edge sensors operating in electrothermal feedback mode, the LTSSM visualizations reveal that a normal-superconducting phase separation takes place in the actual intermediate states.