Superconducting Tunnel Junction Detectors for High-Resolution X-Ray Spectroscopy

X-ray absorption spectroscopy (XAS) is a powerful tool used to study the local molecular and electronic structure of specific elements in a broad range of samples ranging from chemicals and biological samples or tissues to soils and rocks. To achieve the utmost sensitivity, X-ray detectors are required that can separate the fluorescence signal of interest from the high X-ray background originating from other elements in the sample. Conventional X-ray detector technologies are unable to meet both the need for high energy resolution as well as high efficiency. Superconducting tunnel junction (STJ) detectors have become increasingly attractive for energy dispersive soft X-ray detection owing to the combination of their high energy resolution and high count rate capabilities. Most current-generation STJs are based on Nb thin films, but Nb is not the material of choice owing to its low atomic number and a line-splitting artifact that limits the useful energy range for these detectors to & lt;1 keV. During Phase I, STAR Cryoelectronics proposes to develop an innovative process for the fabrication of Ta-based STJ detectors and detector arrays for XAS over a broader energy range with superior energy resolution.Commercial Applications and Other Benefits: The development of XAS has contributed to the significant growth of synchrotron science over the past few years and a broad range of applications in biological sciences, chemistry, materials science, Earth and environmental sciences. The STJ detectors to be developed during Phase I and Phase II represent an enabling technology for the development of next-generation X-ray spectrometers for XAS. Well over 50 synchrotron facilities exist in the world, each of which will have an interest in acquiring one or more XAS spectrometers for their beam lines. STJ detectors are also of interest for applications in astronomy and as extremely sensitive mass spectrometers for applications in genomics and proteomics