| 摘要 |
PROBLEM TO BE SOLVED: To improve the transport efficiency of ions in a first intermediate vacuum chamber at a next stage of an ionization chamber, and to reduce inflow of a gas from the first intermediate vacuum chamber to a second intermediate vacuum chamber to reduce a load of a vacuum pump.SOLUTION: A first ion transport part 12 having an ion funnel structure with a large acceptance is arranged at a first half, and a second ion transport part 14 having a Q-array structure with a small emittance and a large conductance of gas is arranged at a second half. An aperture electrode 13 for applying only a DC voltage is provided between both ion transport parts. An opening inner diameter of the aperture electrode 13 is set to be larger than that of a ring electrode at the final stage of the first ion transport part 12, and an inscribed circle diameter of an electrode plate at the first stage of the second ion transport part 14 is set to be larger than the opening inner diameter of the aperture electrode 13. Thereby, interference of a high-frequency electric field between the first ion transport part 12 and the second ion transport part 14 is alleviated, and ions emitted from the first ion transport part 12 are made enter into the second ion transport part 14 at a low loss. |
