| 摘要 |
1396038 Discharge apparatus NIHON DENSHI KK 10 May 1972 [12 May 1971 7 July 1971 17 Nov 1971] 21960/72 Heading H1D In a high voltage discharge apparatus the surface of an electrode is covered with an insulating or semi-insulating layer to prevent the occurrence of micro-discharges. In one example the control electrode of an electron microscope is covered on the side facing the accelerating electrode with insulating material such as silicon oxide or with a semi-insulating material comprising glass including dispersed lead. A semiinsulating layer should have the product of specific resistance (ohm-cm.) and thickness (microns) within the range 10<SP>3</SP> to 10<SP>12</SP>. The control electrode may be of conductive material coated with insulating material or of insulating material coated with conductive material. The region near and surrounding the aperture for passage of the beam may be coated with conductive material to prevent accumulation of charge, or the aperture may be provided with a metal lining. In another example the accelerating electrodes of an electron or ion beam accelerator are formed of conductive material coated with insulating or semi-insulating material on the side facing the higher potential, or are formed of insulating or semi-insulating material coated with conductive material; in the latter case the insulating material may be cup-shaped with an apertured base, and the cups may be stacked together to form the envelope. |
