Micromass Limited

Other

Vg Instruments Group Limited

Micromass UK Limited

Thermo Fisher Scientific Gmbh

Patrick James Turner

Raymond Clive Haines

Thomas Oliver Merren

James Speakman

Stuart Alan Jarvis

John S Cottrell

David J Kay

Stephen Gordon Bloomfield

A plasma mass spectrometer comprises a plasma torch ( ) for generating ions from a sample introduced into a plasma ( ), a nozzle-skimmer interface ( ) for transmitting said ions into a first evacuated chamber ( ), ion guiding means ( ), an apertured diaphragm ( ) dividing said first evacuated chamber ( ) from a second evacuated chamber, and an ion mass-to-charge ratio analyzer in the second chamber for producing a mass spectrum. The ion guiding means comprises a multipole rod-set ( ), means for applying an AC voltage between rods in the set, and means ( ) for introducing into said ion guiding means an inert gas selected from the group comprising helium, neon, argon, krypton, xenon and nitrogen so that the partial pressure of said inert gas inside said rod-set is at least 10 torr. Interfering peaks in the spectrum, such as Ar , are thereby reduced.

Plasma mass spectrometer

A plasma mass spectrometer comprises a plasma torch (,) for generating ions from a sample introduced into a plasma (,), a nozzle-skimmer interface (,) for transmitting said ions into a first evacuated chamber (,), ion guiding means (,), an apertured diaphragm (,) dividing said first evacuated chamber (,) from a second evacuated chamber, and an ion mass-to-charge ratio analyzer in the second chamber for producing a mass spectrum. The ion guiding means comprises a multipole rod-set (,), means for applying an AC voltage between rods in the set, and means (,) for introducing into said ion guiding means an inert gas selected from the group comprising helium, neon, argon, krypton, xenon and nitrogen so that the partial pressure of said inert gas inside said rod-set is at least 10,torr. Interfering peaks in the spectrum, such as Ar, are thereby reduced.

A Faraday Cup charged-particle detector for use in an isotopic ratio mass spectrometer is provided with a charged-particle collector substrate being at least partially composed of carbon produced by burning wood or other grained or cellular organic material so that the substrate surface has an open cellular structure and wherein the cells are of elongated tubular form. The detector is economic to manufacture, reliable and has an increased lifetime.

Charged-particle detectors and mass spectrometers employing the same

Off-axis interface for a mass spectrometer

The invention provides a mass spectrometer comprising an ion source provided with an electron emitting source and magnets which are cooperable to produce a collimated electron beam within the ion source; a mass analyzer; first and second electrodes which cooperate to limit the angular divergence of the ion beam which emerges from the source along the ion beam axis; and magnetic field screens disposed between the first and second electrode means, which reduce the field due to the magnets along the ion beam axis. In this way the mass discrimination introduced by the magnets in prior ion sources is reduced and the accuracy of isotropic ratio measurements is improved.

Mass spectrometer

In a mass spectrometer, suitable for use in the determination of isotope ratios, having as a mass selector a sector magnet and detector means for detecting and measuring the intensity of ion beams at two or more positions in the focal plane of said sector magnet, the improvement comprises providing the exit (and optionally also the entrance) pole face of said sector magnet with a curvature such that the focal plane of said sector magnet lies substantially at right angles to the ion optical axis as it passes through said focal plane. With this arrangement, motion of detector means between positions in said focal plane by means of mechanical linkages controlled from outside the vacuum system of the mass spectrometer is facilitated.

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Wilmslow, United Kingdom

Patrick James Turner