X-ray transitions associated with electron capture into bare dysprosium

The Lyman and Balmer series in hydrogen-like Dy65+, along with radiative electron capture (REC) into bare Dy66+, have been observed. The X-ray spectra were measured in coincidence with one-electron capture in a beam of 292 MeV amu-1 Dy66+ stored in the ESR storage ring and interacting with an internal argon gas target. The REC line profile was studied in detail and was in good agreement with theory, thus suggesting additional possibilities for spectroscopy.