Abstract: The present invention relates to a vacuum arc electron source having an anode and a cathode facing each other such that they produce a plasma (P) after an appropriate voltage difference has been applied between the anode and the cathode, an electron extractor device (30) and a material-retaining device arranged between the extractor device and the plasma source. According to the invention, the material-retaining device comprises, arranged in the electron extraction direction (F), at least one upstream baffle (10) and a downstream baffle (20) which are each electrically conducting and have apertures (16, 26) arranged in quincunx, such that when the baffles (10, 20) are adjusted a given potential, the plasma (P) does not extend to downstream of the downstream baffle (20).

Abstract: A sealed neutron tube is set forth which contains a low-pressure gaseous deuterium-tritium mixture wherefrom an ion source forms an ionized gas which is guided by a magnetic electron confinement field produced by magnets (8), which source emits the ion beams (3) which traversed an extraction-acceleration electrode (2) and which are projected onto a target (4) so as to produce therein a fusion reaction which causes an emission of electrons. In accordance with the invention, the ion source is of a multi-cell type formed by n Penning-type cells comprising a multi-hole anode (6) which is arranged inside the cathode cavity (7) in order to increase the ion current. The shape and/or the dimensions and/or the position of the multi-hole anode are adapted to the topology of the magnetic field.