Patent ID: 6124675
Filing Date: 2000-09-26
Classification: H01J

Abstract:
An apparatus for generating a beam of metastable species for use in Penning ionization, comprising:a first chamber having a gas inlet and a nozzle outlet, said inlet being connected to a substantially low pressure source of gas suitable for being energized to a metastable state and inducing Penning ionization and Penning energy transfer;a cathode arranged in said first chamber;a second chamber communicating with said nozzle and having a beam outlet substantially in line with said cathode and said nozzle, said second chamber being in communication with a rough vacuum;an anode arranged in said second chamber to one side of a line extending substantially between said cathode, said nozzle and said beam outlet, wherein an electrical discharge formed between said cathode and said anode passes through said nozzle and then deviates from said nozzle to said anode, and an electric field between said cathode and said anode is asymmetric,whereby a jet of gas suitable for being energized to a metastable state emitted from said nozzle containing metastable and ionized species is projected to said beam outlet while ionized species are diverted from said beam outlet and a beam of said gas emitted from said beam outlet has an improved concentration of metastable species.