X-Ray Spectra of a Vacuum Spark with Laser-Assisted Initiation at the Cathode or Anode

We report the results of studying X-ray emission spectra in the energy range 0.2 keV ≤ hν ≤ 20 keV from the plasma of a laser-induced spark discharge with a current of up to 30 kA. The X-ray energy spectra are measured using an absorber method with a set of lithium fluoride LiF(Mg,Ti) thermoluminescence detectors. X-ray measurements by a pin diode are performed as a supplementary diagnostic. It is shown that the X-ray spectra exhibit noticeable differences at different voltage polarities on high-voltage triggering electrode, with intensity and stability being higher across the entire studied range upon initiation at cathodes.