Nijuanoodogatashijukyokubunsekikei

摘要

PURPOSE:To obtain a small tetrode analyzer with high sensitivity by forming facing convex mesh electrodes in the center of a lead-out electrode which is a constituent of the ion source and effectually introducing ions to the tetrode electrode. CONSTITUTION:Inside a semispherical shield electrode 1 consisting of a metallic mesh, a filament electrode 2, a first anode 3 and a second anode 4 are installed in that order. Then, inside the second anode 4, a lead-out electrode 5 having convex-like mesh electrodes 51 in its center is installed to form an ion source. The thus formed ion source is connected to a tetrode electrode 6, a collector shield 8 and a Faraday cup 9, thereby constituting a double-anode-type tetrode analyzer. Due to the lead-out electrode 5 provided with the mesh electrodes 51 forming a convex-lens-like shape, produced ions can be effectually introduced to the tetrode electrode 6. Accordingly it is possible to analyze residual gas of at around 10-10Torr.