An ion source having an anode between two cathodes and means for producing an axial magnetic field. Detremental heating of the cathode present opposite to the ion exit aperture by particles which are accelerated in the reverse direction and have a charge which is opposite to that of the extracted ion beam is prevented. For that purpose said cathode and the means for producing an axial magnetic field have an axial aperture. A collector electrode is present for capturing the relevant particles. The ion source is particularly suitable for a sealed neutron generator.
A single-ring magnetic cusp low gas pressure ion source designed for use in a sealed, nonpumped neutron generator utilizes a cathode and an anode, three electrically floating electrodes (a reflector behind the cathode, a heat shield around the anode, and an aperture plate), together with a single ring-cusp magnetic field, to establish and energy-filtering mechanism for producing atomic-hydrogen ions.
A device for improving the service life and the reliability of a sealed high-flux neutron tube, comprising a first part and a second part which are separated by an accelerator electrode (13). The accelerator electrode forms a shield between said parts and which is integral with the external envelope (15) which is connected to ground. The first and second parts of the tube contain the ion source (9), connected to an adjustable positive potential, and the target (28), respectively, which is connected to a negative potential which can be adjusted with respect to the zero value of ground.
