| 摘要 |
PROBLEM TO BE SOLVED: To create an improved high frequency ion source. SOLUTION: A discharge vessel 2 comprises a gas inlet 10 for gas to be ionized in the discharge vessel 2; a source 9 for gas to be ionized, connected to the gas inlet 10; a high frequency coil 3 surrounding the discharge vessel 2; and a high frequency generator 4 connected to the high frequency coil 3 to generate the high frequency alternating electromagnetic field for ionizing the gas in the discharge vessel 2. Furthermore, an accelerating grid 11 connected to an accelerating voltage source 12 to accelerate ion generated in the discharge container in a form of collecting ion that is going out of the discharge vessel 2 is disposed at the open end part 5 of the discharge vessel 2. The discharge vessel 2 is of tapered shape gradually narrowed toward an end part 6 opposed to the open end part 5, and the high frequency coil 3 at least partially surrounds the gradually narrowed area of the discharge vessel 2. |
