| 摘要 |
PURPOSE:To prevent a sample from being polluted by ions by arranging electrodes with concentric double spherical surfaces on the ion emission face of an ionization chamber so that the spherical core is located in the sample direction and providing many ion extracting holes face to face on both electrodes. CONSTITUTION:Electrons emitted from a filament 2 are allowed to collide with the gas fed from the outside in an ionization chamber 1 for ionization. A coil 3 around the chamber 1 gives the rotating movement to the electrons and improves the ionization efficiency of the gas. An extracting electrode 4 and an accelerating electrode 5 form concentric double spherical surfaces having the spherical core 0 in the sample direction, many holes are provided face to face on both electrodes so as to face the spherical core, thus the ion beams passing the holes of the electrodes 4, 5 have a divergence tendency by the electrode 5 and the velocity component of ions parallel to the electrode 4 face when entering the holes of the electrode 4, thus radiation areas of the ion beams are overlapped on the sample surface, and uniform ion irradiation is performed as a whole. Accordingly, the ion beams pass the center of the chamber 1 and do not collide with an outer wall 6, thus the sample can be prevented from being polluted by ions.
|
