| 摘要 |
PURPOSE:To suppress the outflow of reaction gas without decreasing the incidence efficiency of electrons by providing an ionization chamber with an ionization-electron- incoming hole consisting of a plural number of minute holes. CONSTITUTION:An ionization box (B) is provided with an ion-outgoing hole (a), a sample introduction hole (b), an electron-incoming hole (c) and a reaction-gas introduction hole (d). A filament (F) is placed outside the ionization box (B) and installed facing the electron-incoming hole (c). An electron-accelerating voltage of between the order of ten volts and the order of hundred volts is applied across the filament (F) and the ionization box (B). As a result, electron currents discharged from the filament (F) become an electron-ray flux perpendicular to the side surface of the box (B) and electrons corresponding to the electron-incoming hole (c) on the cross section of the electron-ray flux enter into the box (B). When two electron-incoming holes (c) with a diameter of 0.28mm. are provided for example, the amount of gas flowing out from the box (B) can be made 1/1.4 of that caused when an electron-incoming hole (c) with a diameter of 0.40mm. having the same surface area as the total surface area of two holes (c) with a diameter of 0.28mm. while mainitaining the incidence efficiency of electrons. Therefore an ion source in which the outflow of gas is suppressed can be obtained. |
