摘要 |
PROBLEM TO BE SOLVED: To extract a particle beam generated in a vacuum atmosphere into the atmosphere with the vacuum atmosphere sealed. SOLUTION: A fixed hole 17 for extracting the particle beam 5 is formed in a separation means 13 to separate the vacuum atmosphere 3 and the atmospheric air 15 and is opened and closed at a speed which allows the particle beam 5 to pass through the fixed hole 17 but prevents a gas from passing through the hole 17. |