| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ion source which prevents a gas from being adsorbed to an electron collector during the operation of the ion source and which is not influenced by electron simulated desorption(ESD). SOLUTION: In an ion source, an airtight vacuum chamber 5 which is maintained in a vacuum state is provided, an electron emitter 1 which is arranged inside the vacuum chamber 5 and which emits electrons into the vacuum chamber 5 is provided, an electron collector 2 which holds and moves the electrons emitted from the electron emitter 1 is provided, and an ion collector 3 which pulls out ions generated inside the vacuum chamber 5 is provided. In addition, a heating means which heats the electron collector 2 by a means other than an electron impact means is provided. A temperature rise at 600 deg.C or higher at which a gas emission due to the diffusion of a gas from the electron collector 2 is increased is prevented. A temperature range of 400 to 600 deg.C is set as a temperature range which can prevent the adsorption of gas molecules surely is set.
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