An ion source for use in a radiation generator tube includes a back passive cathode electrode, a passive anode electrode downstream of the back passive cathode electrode, a magnet adjacent the passive anode electrode, and a front passive cathode electrode downstream of the passive anode electrode. The front passive cathode electrode and the back passive cathode electrode define an ionization region therebetween. At least one ohmically heated cathode is configured to emit electrons into the ionization region. The back passive cathode electrode and the passive anode electrode, and the front passive cathode electrode and the passive anode electrode, have respective voltage differences therebetween, and the magnet generating a magnetic field, such that a Penning-type trap is produced to confine the electrons to the ionization region. At least some of the electrons in the ionization region interact with an ionizable gas to create ions.

A high brightness ion source with a gas chamber includes multiple channels, wherein the multiple channels each have a different gas. An electron beam is passed through one of the channels to provide ions of a certain species for processing a sample. The ion species can be rapidly changed by directing the electrons into another channel with a different gas species and processing a sample with ions of a second species. Deflection plates are used to align the electron beam into the gas chamber, thereby allowing the gas species in the focused ion beam to be switched quickly.

An electron impact ion beam source is provided with a pressure chamber to confine a specific high pressure area within excited gas to a small enough volume that the source can be operated at relatively high pressure and still achieve substantial brightness of the extracted ion beam. In particular, the area is configured such that the overall linear dimension along the beam path is less than the mean free path of the ions and the electrons within the chamber. If pressure is increased, the linear dimension must be correspondingly decreased to maximized brightness. By keeping linear dimensions sufficiently small, both incident electrons and extracted ions are enabled to transit the source region without significant energy loss. The new source design allows operation at pressures at least an order of magnitude higher than other known ion sources and thus produces an order of magnitude higher brightness.

An apparatus to generate negative hydrogen ions. The apparatus may include an ion source chamber having a gas inlet to receive H.sub.2 gas; a light source directing radiation into the ion source chamber to generate excited H.sub.2 molecules having an excited vibrational state from at least some of the H.sub.2 gas; a low energy electron source directing low energy electrons into the ion source chamber, wherein H.sup. ions are generated from at least some of the excited H.sub.2 molecules; and an extraction assembly arranged to extract the H.sup. ions from the ion source chamber.

A neutron generator with an ion source within a housing may be used for generating neutrons for neutron logging downhole in a wellbore. The ion source within the housing of the neutron generator may include a hot cathode, an ion source cylinder, a first grid separated from the ion source cylinder, and an extractor separated from the ion source cylinder, the extractor having a second grid.

An electron bombardment ion source assembly for use in a mass spectrometer and including an anode extending along an axis and surrounding an ionization volume. At least two filaments are each configured to thermionically emit electrons and are positioned outside the ionization volume and proximate to the anode. The at least two filaments each comprise an elliptically-shaped portion and non-elliptical portions on either end of the elliptically-shaped portion. The non-elliptically-shaped portions are configured to be mounted in a fixed position relative to the anode to maintain a constant distance between the elliptically-shaped portion and the anode. The elliptically-shaped portion extends along a plane that intersects a plane perpendicular to the axis of the anode at a non-zero angle.

Provided is a negative ion source and a negative ion generation method capable of providing a high negative ion generation efficiency. A negative ion source includes a housing that includes: an inlet from which a sample is introduced; a plasma generation region communicated with the inlet, a plasma being generated by discharge in the plasma generation region; a negative ion generation region in which particles dissociated or excited by a reaction of the generated plasma with the sample are converted into negative ions; and an extraction port communicated with the negative ion generation region, the generated negative ions being extracted outside through the extraction port. The negative ion generation region is filled with a thermionic emission material for generating thermoelectrons by high frequency heating.

One mode of the mass spectrometer according to the present invention is a mass spectrometer including an ion source configured to ionize a component contained in a sample gas, the ion source including: an ionization chamber having an ion ejection opening and forming a space substantially partitioned from an outside inside the ionization chamber; a thermal electron supply unit configured to supply thermal electrons to an inside of the ionization chamber; a magnetic field forming unit configured to form a magnetic field inside the ionization chamber such that the thermal electrons move helically; and a deflection electric field forming unit configured to form a deflection electric field deflecting ions derived from the component generated in the ionization chamber by a direct or indirect action of the thermal electrons in a direction against a force received from the magnetic field when the ions are moving toward the ion ejection opening.