High-resolution kaonic-atom x-ray spectroscopy with   transition-edge-sensor microcalorimeters
  We are preparing for an ultra-high resolution x-ray spectroscopy of kaonic atoms using an x-ray spectrometer based on an array of superconducting transition-edge-sensor microcalorimeters developed by NIST. The instrument has excellent energy resolutions of 2 - 3 eV (FWHM) at 6 keV and a large collecting area of about 20 mm^2. This will open new door to investigate kaon-nucleus strong interaction and provide new accurate charged-kaon mass value. 
S. Okada, D. A. Bennett, W. B. Doriese, J. W. Fowler, K. D. Irwin, S.   Ishimoto, M. Sato, D. R. Schmidt, D. S. Swetz, H. Ta...
physics.ins-det nucl-ex