Speaker: Dr. Orlando Quaranta
Argonne National Laboratory (USA)

Abstract

In this talk, I will present our work on the development and application of superconducting quantum sensors for X-ray science at the Advanced Photon Source (APS). As a DOE Office of Science user facility, APS supports a broad spectrum of experiments in physics, chemistry, materials science, biology, and engineering, many of which place increasingly stringent demands on detector performance. In this context, superconducting transition-edge sensors (TESs) offer a compelling capability by providing energy resolution that substantially surpasses that of conventional semiconductor detectors, while remaining compatible with demanding synchrotron measurement environments.

I will begin with a brief overview of the detector requirements that arise in contemporary X-ray experiments, including X-ray fluorescence spectroscopy, Compton scattering, and resonant soft X-ray scattering. I will then discuss the operating principles of superconducting detectors and outline why TES microcalorimeters are especially well suited to these applications, with particular emphasis on their combination of high sensitivity, low noise, and excellent spectroscopic resolving power.

A central focus of the talk will be the full development pathway required to translate this detector technology into functioning beamline instrumentation. I will describe our approach to device modeling, materials selection, microfabrication, cryogenic integration, and microwave multiplexed readout. I will also highlight several technical challenges that are critical to practical deployment, including the development of electroplated bismuth absorbers for hard X-ray TES arrays, mitigation of thermal crosstalk in multiplexed pixel architectures, and the integration of millikelvin detector systems into both hard and soft X-ray experimental stations.

Finally, I will present recent experimental results that illustrate the scientific opportunities enabled by these instruments at APS. These include high-resolution X-ray fluorescence measurements, hard X-ray Compton scattering studies relevant to lithium-containing and hydrogen-containing materials, and the development of a soft X-ray TES spectrometer for resonant scatteringinvestigations of correlated electron systems. Taken together, these efforts demonstrate that superconducting detector technology is becoming a powerful and versatile platform for next-generation synchrotron science.