| 摘要 |
PURPOSE: To prevent the bad influence of residual magnetism by providing at least one ion trap on the outer side of a gas discharging passage. CONSTITUTION: An ion trap 40 is provided between cathodes 24 and 26 and the point of a triangular laser block. Ion traps 40 and 42 are composed of two coils 46 and 46' installed between blind holes 48 and 48'. As the holes 48 and 48' are provided on the cover side and the bottom face side of a laser block 10 and the holes are provide symmetrically between coil structures, when a current flows through a coil, a magnetic field is generated. When the charged particles of plasma passes through these parts of the holes, these particles are deflected lest these particles reach other electrodes. Two capacitor plates 50 and 50' are provided at the bottoms of the holes 48 and 48'. There is a hole 14 between the two capacitor plates and a high voltage is applied to the capacitor plates during igniting operation. After starting ignition, control voltage is disconnected to remove the electric field to short-circuit the capacitor plates. |
