| 摘要 |
PURPOSE:To suppress the temperature increase of a target upon which a beam is irradiated by insulating the target through an insulating oil used as a primary cooling medium and cooling the insulating oil by introducing cooling water into a metallic pipe. CONSTITUTION:A Faraday cage for measuring a beam current is constituted of a target 3 on which as electron beam is irradiated, a cage 2 for suppressing secondary electrons and reflected electrons and an indicating meter for measuring an effective beam current. The target 3 is installed over a bottom 15, which has a grounding electric potential, with an insulating oil 10 such as mineral oil filled in an insulating cylinder 5 and used as a primary cooling medium interposed. The insulating oil 10 is cooled with cooling water which is introduced into the vacuum through a metallic pipe 11. Owing to the above constitution, it is possible to perform continuous beam irradiation by suppressing the temperature increase of the target even when a large electric power beam is handled, thereby enabling the efficiency of the measuring to be improved. |
