Current signals and X-ray spectra analysis for a vacuum high voltage holding experiment

High Voltage Padova Test Facility (HVPTF) is an experimental device realized to investigate the in vacuum high voltage insulation aspects in support of MITICA, the neutral beam injector prototype for ITER. Moreover, the experiment aims to give a contribution on the understanding of the voltage holding in vacuum, as a physical phenomenon. The two stainless steel electrodes, with few cms of gap in a high vacuum chamber, achieve a saturation breakdown value after about ten hours. A highly time resolved X-rays diagnostic has been recently installed in the device, measuring the X events (single events are detected) produced during the high voltage (up to 400 kV) conditioning: high energy peaks are observed in correspondence to the current peaks collected by the electrodes. This contribution presents a characterization of the current and the X-rays events in terms of frequency, amplitude and their occurrence with respect to the tension between the electrodes.