| 摘要 |
PURPOSE:To enable an arbitrary kind of ions to be taken out by irradiating electron rays on a matter to be ionized or a member holding the matter so as to ionize it. CONSTITUTION:An ion source material 15 such as cesium nitrate is installed in a case 16 with a needle-like electrode 14 pressed upon a hole formed in the bottom of the case 16 by means of a bellows 13 and a movable bar which has a screw mechanism. Next, a filament 18 is heated with a filament power source 22 to around 2,700 deg.C, and the needle-like electrode 14 is heated through electron impulse by supplying voltage from an electron-accelerating voltage source 23, thereby maintaining a part of the ion source material 15 in a molten state. Following that, an ion-accelerating power source 24 is driven, and the needle-like electrode 14 is minutely moved upward while measuring an ionic current 19 so as to supply the molten ion source material 15 to the pointed end of the electrode 14. The thermal resistance of the electrode 14 is increased by providing a thin constricted part 20 near the pointed end in order to increase thermal efficiency. Ionization of the ion source material 15 supplied to the pointed end of the electrode 14 is carried out according to the weight effect of thermal ionization, electrostatic ionization and electron impulse ionization. |
