Measurement of neutrons and X-rays from a vacuum spark

The Jülich DPF I machine was modified to operate as a vacuum spark. It was established that with an operating pressure varying from 10^-4 to 10^-5 torr a voltage within the range of 14–17 kV was necessary to ensure a dense plasma phase as indicated by soft X-ray pinhole photography and current measurements. Operating with a LiD-filled channel in the anode, occasional bursts of neutrons were detected with a time-of-flight scintillator system. The yield, however, was erratic and below 10⁷ per discharge.