Abstract: Apparatus (e.g., ion source), systems (e.g., residual gas analyzer), and methods provide extended life and improved analytical stability of mass spectrometers in the presence of contamination gases while achieving substantial preferential ionization of sampled gases over internal background gases. One embodiment is an ion source that includes a gas source, nozzle, electron source, and electrodes. The gas source delivers gas via the nozzle to an evacuated ionization volume and is at a higher pressure than that of the evacuated ionization volume. Gas passing through the nozzle freely expands in an ionization region of the ionization volume. The electron source emits electrons through the expanding gas in the ionization region to ionize at least a portion of the expanding gas. The electrodes create electrical fields for ion flow from the ionization region to a mass filter and are located at distances from the nozzle and oriented to limit their exposure to the gas.

Abstract: Apparatus (e.g., ion source), systems (e.g., residual gas analyzer), and methods provide extended life and improved analytical stability of mass spectrometers in the presence of contamination gases while achieving substantial preferential ionization of sampled gases over internal background gases. One embodiment is an ion source that includes a gas source, nozzle, electron source, and electrodes. The gas source delivers gas via the nozzle to an evacuated ionization volume and is at a higher pressure than that of the evacuated ionization volume. Gas passing through the nozzle freely expands in an ionization region of the ionization volume. The electron source emits electrons through the expanding gas in the ionization region to ionize at least a portion of the expanding gas. The electrodes create electrical fields for ion flow from the ionization region to a mass filter and are located at distances from the nozzle and oriented to limit their exposure to the gas.

Abstract: Apparatus (e.g., ion source), systems (e.g., residual gas analyzer), and methods provide extended life and improved analytical stability of mass spectrometers in the presence of contamination gases while achieving substantial preferential ionization of sampled gases over internal background gases. One embodiment is an ion source that includes a gas source, nozzle, electron source, and electrodes. The gas source delivers gas via the nozzle to an evacuated ionization volume and is at a higher pressure than that of the evacuated ionization volume. Gas passing through the nozzle freely expands in an ionization region of the ionization volume. The electron source emits electrons through the expanding gas in the ionization region to ionize at least a portion of the expanding gas. The electrodes create electrical fields for ion flow from the ionization region to a mass filter and are located at distances from the nozzle and oriented to limit their exposure to the gas.

Abstract: Apparatus (e.g., ion source), systems (e.g., residual gas analyzer), and methods provide extended life and improved analytical stability of mass spectrometers in the presence of contamination gases while achieving substantial preferential ionization of sampled gases over internal background gases. One embodiment is an ion source that includes a gas source, nozzle, electron source, and electrodes. The gas source delivers gas via the nozzle to an evacuated ionization volume and is at a higher pressure than that of the evacuated ionization volume. Gas passing through the nozzle freely expands in an ionization region of the ionization volume. The electron source emits electrons through the expanding gas in the ionization region to ionize at least a portion of the expanding gas. The electrodes create electrical fields for ion flow from the ionization region to a mass filter and are located at distances from the nozzle and oriented to limit their exposure to the gas.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.

Abstract: Apparatus, methods and systems are provided to inhibit a sightline from a charged particle source to an analyzer and for changing a baseline offset of an output spectrum of an analyzer. A supply of charged particles is directed through a hollow body of a deflector lens that is positioned relative to a charged particle source and an analyzer. A flow path along a preferred flow path through a deflector lens permits passage of the ions from the source to the detector while inhibiting a sightline from the detector to the source in a direction parallel to the central longitudinal axis of the deflector lens.