PURPOSE: To make it possible to measure the dimension of electron beam without lowering S/N of a signal, by linearily approximating the intensity distribution of electron beam to calculate the dimension thereof.
CONSTITUTION: Electron beam 10 having a rectangular cross-sectional area is scanned in an x-direction and a y-direction on metal wires 1x, 1y by a polarizer 30 and a scanning power source 31. This beam passes a throttle 11 and is detected by a detector 12 while detection output is accumulated in a memory 33 through an amplifier 13 and an A/D converter 32 and, thereafter, taken in an operation circuit 34 to calculate an approximate straight line equation, wherein the address on the memory 33 is set to a variable and a data value to a dependent variable, to calculate the address of the memory 33. The dimension of electron beam is calculated from the width of said address and supplied to an external display apparatus 36 through memory 35.
SAITOU NORIO
OOKUBO TSUNEO
NIPPON TELEGRAPH & TELEPHONE
| JPS5551338A | 1980-04-15 |