SBIR-STTR Award

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

X-ray absorption spectroscopy is a widely used experimental technique for studying the composition and chemistry of materials and is one of the driving forces behind the explosive growth of synchrotron light sources and their increase in brightness by many orders of magnitude. However, advances in detector technology have not kept pace with advances in synchrotron brightness, leading to limitations on scientific output and research capabilities. In Phase I, STAR Cryoelectronics developed an innovative and streamlined process for the fabrication of high energy resolution, high count rate superconducting tunnel junction (STJ) X- ray detectors based on Ta thin films that will meet growing needs for advanced detectors for synchrotron science applications. Several prototype STJ detectors and detector arrays were successfully fabricated and characterized during Phase I. Record energy resolution has been achieved, and multi-pixel arrays with up to 112 pixels were successfully fabricated. During Phase II, STAR Cryoelectronics plans to further improve energy resolution, increase the maximum count rate per pixel, and enhance production yield and detector reliability. Commercial Applications and Other

Benefits:
The new STJ detector arrays represent the enabling technology for two significant commercial applications: X-ray absorption spectroscopy (XAS) at the synchrotron, which is used to study the local molecular and electronic structure of specific elements, and X-ray microanalysis in conjunction with a scanning electron microscope (SEM), which is used for defect and failure analysis. XAS samples can be highly diluted and generally do not require substantial pre- treatment, and they can range from chemicals and biological samples or tissues to soils and rocks. The development and commercialization of multi-pixel arrays of advanced STJ X-ray detectors will meet growing needs for improved detector instrumentation for applications in synchrotron science such as XAS. The significant performance enhancements that will be realized with the proposed STJ X-ray detector arrays will lead to greater scientific productivity and return on the Nations substantial capital investment in synchrotron facilities.