| 摘要 |
PURPOSE:To measure the shape of charged particle beam in a real time, by converting analogue output voltage generated when the position of a detection wire is detected to a digital signal and displaying said signal after D/A conversion. CONSTITUTION:A detection wire 22 is hooked to the open end of a C-shaped frame 21 under tension in a state insulated from the frame 21 and moved by the frame 21 so as to traverse a charged particle beam path. When the wire 22 enters the cross-section of the beam, voltage is generated in the wire 22 by charged particle beam 15 and converted to a digital signal by an A/D converter 26 to be stored in a memory 27. The position signal of a position detector 25 passes through a change-over device 28 to be inputted to a counter 29 where comes to the address signal of the memory 27 to be stored in the memory 27 and the digital signal from the converter 26 is entered in a predetermined address. A beam shape is stored in the memory 27 by sweeping the wire once and, thereafter, the change-over device 28 is changed over to connect the counter 29 to a clock circuit 32 and the digital signal from the memory 27 is inputted to a D/A converter 30 to be displayed on a display device 31.
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