PROCESS OF GENERATION OF NEGATIVE IONS IN IONIZATION CHAMBER OF COMPONENT ANALYZER AND DEVICE FOR ITS REALIZATION Russian patent published in 2002 - IPC

FIELD: analyzers of chemical composition such as electron capture detector, spectrometer of ionic mobility or mass spectrometer. SUBSTANCE: according to process of generation of negative ions in ionization chamber of component analyzer electron beam formed in vacuumed space and accelerated by action of applied voltage is directed on to membrane made of gas impenetrable material that separates vacuumed space from ionization chamber. Beam of thermal electrons emitted by surface of part of membrane heated by beam of electrons directed from vacuumed space on to heated section of membrane is employed for ionization of electron-accepting substances in ionization chamber. Specific power P of beam of electrons directed on to heated section of membrane is chosen from condition 0.01 W/sq cm <P <1.0 W/sq cm. Device for realization of process has vacuumed chamber where source of nonradioactive electrons is placed, membrane separating vacuumed chamber from ionization chamber. Membrane has at least two layers produced from different materials. One layer is made of dielectric material, for instance, Al₂O₃, the other layer covering surface of first layer on side of ionization chamber is made of metal, for example Os, that does not form any chemical combinations at high temperatures in air. Thickness of metal layer is 0.005-0.02 mcm. EFFECT: development of process of generation of negative ions and device for its realization which do not require usage of high-voltage sources. 11 cl, 2 dwg