| 摘要 |
PURPOSE:To prevent the generation of electric discharge so as to produce a great acceleration electric field by locating the fixed area of the metallic mesh of a photoelectron-accelerating electrode for an image tube apart from the photoelectric screen without changing the distance between the mesh and the photoelectric screen. CONSTITUTION:A Kovar mesh ring 21 is used to fix a copper mesh 23 and the outer periphery of the surface of the mesh ring 21 facing a photoelectric screen is thinner than the chamfered inner periphery. After the mesh 23 is placed on the ring 21, a ring 22 made of a stainless steel is pressed upon the periphery of the mesh 23 and fixed by spot welding, thereby making an electrode. This electrode is used as a photoelectron-accelerating electrode 2 for an image tube such as a mesh-like electrode for a streak tube which is used to accelerate optical electrons emitted from a photoelectric screen 1 in a high electric field. Therefore, even when the acceleration electric field between the photoelectric screen 1 and the accelerating electrode 2 is increased, it is possible to prevent electric discharge from developing in welded spots 24. Consequently, it is possible to achieve improved time resolution. |
