| 摘要 |
PURPOSE:To prevent any defective injection homogeneity which might be caused due to the deterioration or the like of a scanning power source by detecting the strain of the form of output triangle waves by comparing the energy efficiencies of the component spectra of the form of the output triangle waves. CONSTITUTION:The output of a scanning power source 3 for applying high- voltage triangle waves to an electrostatic deflecting plate 2 for scanning an ion beam 1, is drawn with a voltage divider 4. The signal of triangle waves drawn is applied to narrow-range filters 5, 5.... Each filter 5 has a central frequency corresponding to the fundamental frequency (f0) of the triangle wave as well as to the frequencies (f1), (f2)...(fn) of n component higher harmonics of arbitrary orders. Besides, the range of each filter 5 is sufficiently narrower than the distances between the component frequencies of triangle waves. The output voltage (V0), (V1)...(Vn) of the filters 5 are delivered to window comparators (C0), (C1), (C2).... If wave form becomes abnormal and the frequency spectrum becomes apart from the normal level, one or more of the comparators (C0), (C1, (C2)...produes an output, which is applied as an injection operation HOLD signal to an ion injector through an OR gate 7, thereby preventing any defective injection. |
