| 摘要 |
PURPOSE: To form hole sections through which electrons pass with no hole drift by allowing fine grains injected at a high speed to collide with grid electrodes to form the hole sections. CONSTITUTION: Recessed face-shaped electrode bodies 11, 12 corresponding to the first grid electrode and the second grid electrode are prepared, and their bottom faces are faced to each other at a prescribed gap. Bead glasses 13 are bridged across both support members 11b, 12b to integrally fix the electrode bodies 11, 12. A pair of electrode bodies 11, 12 thus fixed are fitted to a jig 14, and hole sections through which electrons pass are formed by a fine grain blasting machining device 15 blasting fine grains 16 through a nozzle 15a at a high speed. The fine grains 16 colliding with the electrode bodies 11, 12 preferably have the grain size of about 20μm or below.
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