THERMAL IONIZATION TYPE ION SOURCE

摘要

PURPOSE:To decrease the width of the energy distribution of ions led out from an ion source by using an anode which has an area opposite to the ion-leading- out hole of the anode and either protruding inside the anode or having a projection. CONSTITUTION:Electrons discharged from a filament 2 are converged by a diaphragm 5 before being introduced inside an anode 1. At this point, some of the electrons deviating from the originally determined orbit are recovered by the electron collector 11 of the anode 1. Accordingly, the space in which the electron beam travels is controlled by the diaphragm 5 and the collector 11. The top end of the anode 1 either consists of an inwardly protruding meshy area 9 or is provided with a projection in order to concentrate the electric line of force around the central axis of the anode 1. The electron implantation hole 10 of the anode 1 through which electrons from the filament 2 are implanted into the anode 1 is located above the diaphragm hole of the repellers 6 and 7. The electron beam is implanted downward toward a tetrode 8.