Improvements to a source emitting a continuum from the visible to the soft x rays.

The authors describe the following improvements to a three-electrode vacuum spark source: reduction of the size of the triggering device, electronic control of the discharge rate, and a completely coaxial mounting of the electrodes along the optical axis. The performance thus obtained is specified, and absorption spectra are shown as examples of the use of the source in the far ultraviolet (100 A to 2000 A).