Proximity effect model for x-ray Transition Edge Sensors

TL;DR

This paper introduces a proximity effect model based on Usadel equations to predict and optimize the performance of superconducting Transition Edge Sensors, reducing the need for extensive experimental testing.

Contribution

The authors develop a novel proximity effect model that accurately predicts TES performance based on device geometry and material composition.

Findings

Model successfully reproduces I-V curves for studied devices

Suggests optimal size and geometry for TESs

Future device modeling can reduce testing costs

Abstract

Transition Edge Sensors are ultra-sensitive superconducting detectors with applications in many areas of research, including astrophysics. The device consists of a superconducting thin film, often with additional normal metal features, held close to its transition temperature and connected to two superconducting leads of a higher transition temperature. There is currently no way to reliably assess the performance of a particular device geometry or material composition without making and testing the device. We have developed a proximity effect model based on the Usadel equations to predict the effects of device geometry and material composition on sensor performance. The model is successful in reproducing I-V curves for two devices currently under study. We use the model to suggest the optimal size and geometry for TESs, considering how small the devices can be made before their performance is compromised. In the future, device modelling prior to manufacture will reduce the need for time-consuming and expensive testing.