| 摘要 |
PROBLEM TO BE SOLVED: To allow even an unskilled person to detect ions stably, by obtaining data of position and shape of ion beams entering a mass filter, and controlling voltage impressed to each electrode of an ion lens based on the data so that the beams enter the mass filter in an optimum state of the position and shape. SOLUTION: Scanning signals Dx, Dy fed to each scanning electrode 21a-21d are changed to move a position of a beam-scanning spot 24. Ions entering an entrance hole 23 are separated and detected by a mass filter 8, and counted at a data-processing part. When the counting at the data-processing part is synchronized with the signals Dx, Dy, data of a position and a shape of beams entering the filter 8 when the beams are not deflected by the signals Dx, Dy are obtained. The voltage of an electrode 7b of an ion lens 7 and then a coefficient (k) of a voltage to be impressed to a deflector 20 are sequentially changed. A value when a beam diameter becomes minimum, an asigmatism becomes minimum and a counting rate of peaks becomes maximum is set to be optimum. Accordingly, even an unskilled person can optimize easily. |
