| 摘要 |
PURPOSE:To perform blanking of ion rays in a mass spectrograph, which is constituted by using two parallel nonmagnetic electrodes and two parallel nonmagnetic electrodes which are perpendicular to the former two electrodes, by changing the voltages of the electrodes so as to make it impossible for ion rays to pass through the hole of a throttle plate according to necessity. CONSTITUTION:Nonmagnetic electrodes 3 and 4 are placed parallel to the traveling direction (optical axis) of ion rays discharged from an ion source. Nonmagnetic electrodes 5 and 6 are placed perpendicular to the electrodes 3 and 4. A throttle plate 8 having a hole 7 on the optical axis of the ion rays, is placed perpendicular to the optical axis in the back of the electrodes 3, 4, 5 and 6. The electrodes 5 and 6 are permanent magnets. By directing a magnetic field (B) toward -x direction, lighter ion rays 1 are more greatly curved than heavy ion rays 2. By applying voltages V and -V to the electrodes 3 and 4 respectively, the ion rays 2 are deflected toward -y direction by means of an electric field (E) and only ion rays 1 passing through the hole 7 can be taken out. In addition, by applying voltage W to either the electrodes 5 or electrodes 6 and earthing the other electrodes, the ion rays 1 and 2 are respectively polarized in directions 1' and 2' and no ions pass through the hole 7 thereby enabling blanking to be performed. |
