Contact ionization ion source

Claim 2

An ion source for use in an evacuated vessel, said source comprising: means for supplying a gaseous or vaporized ionizable material in said evacuated vessel; an ionization electrode having at least one active surface of substantial area formed of a material capable of ionizing said ionizable material by contact therewith; means for heating said ionization electrode; an open-structured electrode having a multiplicity of openings therein and spaced from said active surface or surfaces by space free of intervening field-affecting structures; means for producing and maintaining, in the space between said active surface or surfaces and said open-structured electrode, a magnetic field of a character favoring the formation in said space of a stable plasma, and means for applying to said open-structured electrode an electronegative potential barely sufficient to repel electrons issuing from said plasma and to favor movement through said electrode of ions issuing from said plasma.

Claim 3

An ion source as defined in claim 1, in which said open-structured electrode is a grid electrode, in which, further, said electro-negative potential is such as to provide an average field strength between 0.3 and 2 volts per centimeter in the space between surface or surfaces and said open-structured electrode, and in which the axis of said magnetic field is essentially perpendicular to said active surface or surfaces.

Claim 4

An ion source as defined in claim 1, in which said open-structured electrode is a grid electrode, and said surface or surfaces and said open-structured electrode are so disposed that the field in the space therebetween is essentially unidirectional and essentially aligned in the direction of said magnetic field.

Claim 5

An ion source as defined in claim 1, in which said ionizable material is a vaporized material and in which evaporator means are provided within said vessel for vaporizing said ionizable material.

Claim 6

An ion source as defined in claim 4, in which said evaporator means is disposed immediately adjacent said space between said active surface or surfaces and said open-structured electrode.

Claim 7

An ion source as defined in claim 4, in which said ionization electrode is traversed by openings whose wall surfaces consist of said material capable of ionizing said ionizable material by contact therewith and in which, further, said evaporator means is disposed on the opposite side of said ionization electrode from said open-structured electrode and adapted to produce vapor for ionization in said openings or at said active surface beyond said openings.

Claim 8

An ion source as defined in claim 1, in which said material capable of ionizing said ionizable material by contact therewith is a substance selected from the group consisting of tungsten, rhenium, tantalum and ceramic materials that are electrically conductive at the operating temperature of said ionization electrode.

Claim 9

Apparatus for separation of ionizable isotopes adapted for operation on the principle of a mass spectrometer in an evacuated vessel, which apparatus includes: an ion source comprising an ionization electrode having at least one active surface formed of a material capable of ionizing said isotopes by contact therewith; means for introducing said isotopes in gaseous or vapor form in the space adjacent to said ionization electrode; means for heating said ionization electrode; an open-structured electrode having a multiplicitY of openings therein and spaced from said active surface or surfaces by space free of intervening structures; means for producing and maintaining, in the space between said active surface or surfaces and said open-structured electrode, a magnetic field of a character favoring the formation in said space of a stable plasma, and means for applying to said open-structured electrode an electro-negative potential barely sufficient to repel electrons issuing from said plasma and to favor movement through said electrode of ions issuing from said plasma.

Claim 10

Apparatus for separation of ionizable isotopes adapted for operation on the principle of a mass spectrometer in an evacuated vessel, which apparatus includes: an ion source comprising an ionization electrode having at least one active surface formed of a material capable of ionizing said isotopes by contact therewith; means for introducing said isotopes in gaseous or vapor form in the space adjacent to said ionization electrode; means for heating said ionization electrode; an open-structured electrode having a multiplicitY of openings therein and spaced from said active surface or surfaces by space free of intervening structures; means for producing and maintaining, in the space between said active surface or surfaces and said open-structured electrode, a magnetic field of a character favoring the formation in said space of a stable plasma, and means for applying to said open-structured electrode an electro-negative potential barely sufficient to repel electrons issuing from said plasma and to favor movement through said electrode of ions issuing from said plasma.