| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an ion beam multiple grid optical system realizing a long service life without causing a reduction of thrust. <P>SOLUTION: The multiple grid optical system comprises a screen grid 10 having a plurality of openings for extracting an ion beam from a plasma production chamber in an ion thruster; an acceleration grid 11 and a speed-reduction grid 12. The optical system comprises the screen grid 10 in which a spattering- resistant ceramic film 33 is coated on a surface opposed to the plasma production chamber of the screen grid and the spattering-resistant ceramic film 33 is not almost deposited on a side surface of opening; and an acceleration grid 10 in which the spattering-resistant ceramic film 33 is coated on a side surface of the acceleration grid 11 and a surface opposed to the speed-reduction grid 12. The spattering-resistant ceramic film 33 is formed by making the opening of the screen grid by a metal pin. <P>COPYRIGHT: (C)2003,JPO |
