Abstract: The invention relates to an apparatus for treating samples comprising in a vacuum enclosure a cathode, an actual anode and a grid, as well as means for supplying the sample to the enclosure, a high voltage generator, a capacitor C.sub.1 charged by way of the said generator, a spark gap switch for producing a high energy pulse between the cathode and the grid, said switch being connected to one terminal of said capacitor, an element for producing pulses controlling the spark gap switch and a capacitor C.sub.2 having a capacitance above that of capacitor C.sub.1, charged by way of the generator used for producing between the actual anode and the cathode an electric field for accelerating and extracting electrons used for the bombardment of the sample.