Soft X-Ray Performance of High-Resolution Superconducting Spectrometers

Abstract

We are developing high-resolution, broad-band, superconducting X-ray spectrometers for applications in materials science, astrophysics and biophysics. These spectrometers are superconducting microcalorimeters based on superconducting tunnel junction sensors made from thin films of niobium and aluminum. The energy resolution of these spectrometers can be more than an order of magnitude better than that of the best Si(Li) or Ge(Li) detectors. We present results of recent measurements characterizing the performance of these detectors for X-ray energies from 70 eV to 500 eV, where the energy resolution ranged from 4 eV FWHM (at 70 eV) to 12 eV FWHM (at 500 eV).