Filament for mass spectrometer thermo ionisation source - has prismatic vaporisation filament with axis parallel to extracted ions and two open bases, one adjacent ionisation filament

摘要

A symmetrical cylindrical element (401), made in a refractory metal such as Rhenium or Tungsten, forms the evaporating surface. The sample (404) is deposited on the inner surface of the cylindrical filament. Evaporated atoms or molecules strike the thermo-ionising plate (402) which is maintained at a temp. of 2000 to 2500 degrees C. Ionised atoms recoiling from the plate pass back through the cylinder along its axis (E) and emerge from the open top. The filament cylinder can be made of the same dia. as the housing plate width. In all the various forms, wings are attached to the cylinder and are welded to electrical supply terminals for passage of the heating current.