HOT-CATHODE ELECTRON IMPACT TYPE ION SOURCE WITH LEAD-OUT ELECTRODE

摘要

PURPOSE:To produce a widely increased amount of ions by installing a hot cathode, an electron diaphragm electrode and a thermion-leading-out electrode around a cylindrical anode in a hot-cathode electron impact type ion source for a tetrode analyzer. CONSTITUTION:An electron diaphragm electrode 2 is installed around a cylindrical cage-like anode 1 which has an electron permeable grid-like or mesh-like circumferential surface. After that, a mesh-like thermion-leading-out electrode 3 of 10-20 mesh is installed outside the electron diaphragm electrode 2 and an annular hot cathode 4 is installed outside the mesh-like thermion-leading-out electrode 3, thereby constituting a hot-cathode electron impact type ion source for a tetrode analyzer. Owing to the above constitution, the effect of the mesh-like lead-out electrode 3 reduces the influence of space charges while causing an increased amount of thermions to be discharged thereby introducing a great amount of electrons into the cylindrical cage-like anode 1. Consequently, it is possible to widely increase the amount of ions produced.