| 摘要 |
PURPOSE:To obtain an X-ray pre-ionization device where a cathode is long in service life by a method wherein a cathode section where a dispenser cathode is used as a thermion emission material and a vacuum vessel are provided, and a coolant flow path is provided inside the wall of the vacuum vessel. CONSTITUTION:An electron beam generated from a cathode section 1 where a dispenser cathode is used as a thermion emission material is made to collide against a target 2 and generate X-rays through braking radiation. A vacuum vessel 3 is formed of cooper material, a coolant flow path is provided inside the wall of the vessel 3 at a depth of 1cm from the inner wall plane, and cooling water is made to flow through the flow path concerned to cool. The vacuum vessel 1 is exhausted high in degree of vacuum. At this point, a dispenser cathode is used as a thermion emission material, so that an electron beam can be emitted at a high repetition rate and X-rays enough in dose required for the pre-ionization of a gas laser can be obtained. When the cathode is heated, the wall of the vacuum vessel 1 becomes slightly higher than the coolant flow path in temperature by 0.1-0. 2 deg.C and is prevented from rising in temperature. Therefore, the adsorbed impurities are hardly discharged, and a cathode is protected against deterioration. |
