Metastable atom bombardment source
AssigneeUniversity of Montreal
InventorsMichel J. Bertrand, Denis Faubert, Olivier Peraldi, Andre L'Heureux
Life of this patent
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Abstract
The metastable atom bombardment source provides a charged particle free beam of metastable species that can be used to bombard and ionize organic and inorganic substances in a gas phase. The metastable atoms are produced by inducing a discharge in a gas (rare gases or small molecules). The discharge is curved between the cathode and anode, with the cathode located in a medium pressure zone and the anode located off-axis in a low pressure zone; A nozzle located between the cathode and the anode provides a collimated beam of metastable atoms of low kinetic energy that is directed at an ion volume containing the substances to be analyzed.
Claims15
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.
The apparatus as defined in clam 1, wherein said anode is off-axis and planar, whereby said discharge has greater stability.
An apparatus for generating a beam of metastable atoms 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;
- a first electrode arranged in said first chamber;
- a second chamber communicating with said nozzle and having a beam outlet substantially in line with said first electrode and said nozzle, said second chamber being in communication with a rough vacuum;
- a second electrode arranged in said second chamber to one side of a line extending substantially between said first electrode, said nozzle and said beam outlet, wherein an electrical discharge arc formed between said first and second electrodes passes through said nozzle and then deviates from said nozzle to said second electrode, and an electric field between said first and second electrodes 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.
Dependencies are inferred from the claim text.