| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: a detection-efficiency varies with the detected position of MCP (Microchannel Plate). SOLUTION: The MCP assembly having three-step structure using three MCPs is utilized. The first step MCP 81 does not have the purpose of largely multiplying the number of electrons but of sending the detected object into the second step of MCP 82 after capturing it. The detected objects 84 and 85 which collide with the channel of the first step of MCP 81 are transformed to secondary electrons by low multiplication and enter the second step of MCP 82, and the divergence angle is restricted and the detected object 86 which does not collide with the channel enters the second step of MCP 82. Thus, the channel direction of the second step MCP is prevented from corresponding to the advancing direction of the detected object. The number of secondary electrons is increased up to the electric charge which is fully read out from the whole surface of MCP by the second step and the third step of MCP. COPYRIGHT: (C)2011,JPO&INPIT |
