Superconducting transition-edge microcalorimeters for X-ray microanalysis

We have developed high-performance x-ray microcalorimeters based on superco nducting transition-edge sensors. These superconducting detectors, which ar e cooled by a compact adiabatic demagnetization refrigerator mounted on a s canning electron microscope, provide significant new capabilities for x-ray microanalysis. The performance characteristics of these detectors are near ly ideal for many applications in x-ray microanalysis, attaining an energy resolution of 3-4 eV at a counting rate of 500 s(-1) and an effective colle ction area of 4 mm(2). The excellent energy resolution enables measurements of chemical shifts in x-ray spectra caused by changes in electron binding energy due to chemical bonding. Another important application of these dete ctors is analysis of contaminant particles and defects for the semiconducto r industry. We present data demonstrating the analysis of particles on Si w afers, including 0.3 mu m tungsten particles and 0.1 mu m alumina particles .