Ion source having a mass separation device

An ion source having a mass-separation device which converts material gas into plasma and exhausts ion beams from the plasma comprising a vacuum chamber having a gas inlet and an ion outlet, a vacuum pump for making the chamber vacuum, a discharge device for generating discharge in the chamber to excite material gas into plasma, a plasma electrode plate having ion holes and being installed at the outlet of the chamber, the plasma electrode plate being biased at a high positive voltage of the chamber, an extraction electrode plate having ion holes at the same positions and being installed next to the plasma electrode plate at the outlet of the chamber, the extraction electrode being biased at a high positive voltage lower than the voltage of the plasma electrode plate, a mass-separation electrode plate having ion holes at the same positions and being installed next to the extraction electrode plate, the mass-separation electrode being biased at a high positive voltage lower than the voltage of the extraction electrode plate, an acceleration electrode plate having ion holes at the same positions at the mass-separation electrode, and being installed next to the mass-separation electrode at the outlet of the chamber, the acceleration electrode plate being biased at a negative small voltage and a grounded electrode plate having ion holes at the same positions as the acceleration electrode plate and being installed next to the acceleration electrode plate at the outlet of the chamber, characterized in that each ion hole of the extraction electrode plate is provided with a Wien filter including permanent magnets facing each other with different magnetic poles for producing a magnetic field perpendicular to an axial direction of the ion holes and electrodes facing each other and being biased at different voltages for producing an electric field perpendicular both to the magnetic field and to the axial direction, ion beams whose mass is equal to a reference mass M.sub..quadrature. makes a straight way through the Wien filters of the extraction electrode plate by receiving the same but reverse forces from the electric field and the magnetic field, but the other ion beams whose mass is not equal to the reference mass M.sub..quadrature. make an arc way through the Wien filters by receiving different, reverse forces from the electric field and the magnetic field, and collide with the next mass-separation electrode plate.

An ion source having a mass-separation device which converts material gas into plasma and exhausts ion beams from the plasma comprising a vacuum chamber having a gas inlet and an ion outlet, a vacuum pump for making the chamber vacuum, a discharge device for generating a discharge in the chamber to excite material gas into plasma, a plasma electrode plate having ion holes and being installed at the outlet of the chamber, the plasma electrode plate being biased at a high positive voltage lower than the voltage of the chamber, a pulling-out electrode plate having ion having at the same positions as the plasma electrode plate and being installed next to the plasma electrode plate at the outlet of the chamber, a filter electrode plate having ion holes at the same positions as the pulling-out electrode plate and being installed next the pulling-out electrode plate, the filter electrode plate being biased at a high positive voltage equal to or lower than the voltage of the pulling-out electrode plate, a mass-separation electrode plate having ion holes at the same positions as the filter electrode plate and being installed next to the filter electrode plate at the outlet of the chamber, the mass-separation electrode plate being biased at a high positive voltage equal or lower than the voltage of the filter electrode, an acceleration electrode having ion holes at the same positions as the mass-separation electrode plate and being installed next to the mass-separation electrode plate at the outlet of the chamber, the acceleration electrode plate being biased at a negative small voltage, and a grounded electrode plate having ion holes at the same positions as the acceleration electrode plate and being installed next to the acceleration electrode plate at the outlet of the chamber, characterized in that each ion hole of the filter electrode is provided with a Wien filter including permanent magnets facing each other with different magnetic poles for producing a magnetic field perpendicular to an axial direction of the ion holes and electrodes facing each other and being biased at different voltages for producing electric field perpendicular both to the magnetic field and to the axial direction, ion beams whose mass is equal to a reference mass M.sub..quadrature. make a straight way through the Wien filters of the filter electrode plate by receiving the same but reverse forces from the electric field and the magnetic field, but other ion beams whose mass is not equal to the reference mass M.sub..quadrature. make an arc way through the Wien filters by receiving different, reverse forces from the electric field and the magnetic field, and collide with the next mass-separation electrode plate.