Beyond One-Thousandth Energy Resolution with an AlMn TES Detector

TL;DR

This paper presents the development and testing of an AlMn TES detector achieving unprecedented energy resolution for X-ray detection, demonstrating its potential for high-precision spectrometry.

Contribution

The first demonstration of an AlMn TES achieving sub-0.1% energy resolution in X-ray detection, expanding its application beyond CMB experiments.

Findings

Achieved 12.1 eV FWHM energy resolution at 17.48 keV

Demonstrated the suitability of AlMn TES for high-resolution X-ray spectroscopy

First to report sub-0.1% energy resolution with AlMn TES

Abstract

The superconducting Transition-Edge Sensor (TES) is a critical technology for next-generation X-ray spectrometers, known for its exceptional energy resolution. In the last decade, TESs based on AlMn alloy films have been extensively used in several cosmic microwave background (CMB) experiments. The advantages of simple fabrication process and easily tunable critical temperature make them an alternative to bilayer TESs. However, they have rarely been applied to X-ray detection until now. We developed an annular AlMn TES for X-ray detection and tested it in a dilution refrigerator with a Superconducting Quantum Interference Device (SQUID) amplifier, achieving an Full Width at Half Maximum (FWHM) of 12.1 +- 0.3 eV at 17.48 keV. To the best of our knowledge, this is the first demonstration of an AlMn TES achieving an energy resolution below 0.1%, highlighting its potential for high-resolution X-ray detection.