Calorimetric readout of a superconducting proximity-effect thermometer

TL;DR

This paper introduces a novel calorimetric method for reading out a superconducting proximity-effect thermometer, enhancing sensitivity at sub-300 mK temperatures by detecting Joule heating-induced temperature changes.

Contribution

The authors present a new calorimetric approach for superconducting thermometry that improves sensitivity compared to traditional voltage-based detection methods.

Findings

Enhanced sensitivity at low temperatures below 300 mK

Effective detection of the superconducting-normal transition via Joule heating

Potential for improved thermometry in quantum applications

Abstract

A proximity-effect thermometer measures the temperature dependent critical supercurrent in a long superconductor - normal metal - superconductor (SNS) Josephson junction. Typically, the transition from the superconducting to the normal state is detected by monitoring the appearance of a voltage across the junction. We describe a new approach to detect the transition based on the temperature increase in the resistive state due to Joule heating. Our method increases the sensitivity and is especially applicable for temperatures below about 300 mK.