Abstract: A focal plane detector assembly of a mass spectrometer includes an ion detector configured to detect ions crossing a focal plane of the spectrometer and an electrically conductive mesh lying in a plane parallel to the focal plane, positioned such that ions exiting a magnet of the mass spectrometer pass through the mesh before contacting the ion detector. The mesh is maintained at a low voltage potential, relative to a circuit ground, which shields ions passing through the magnet from high voltage charges from other devices, such as microchannel plate electron multipliers. The mesh may be mounted directly to the magnet or positioned some distance away. The detector array may include any suitable device, including a faraday cup detector array, a strip charge detector array, or a CCD detector array.

Abstract: An analytical instrument, such as a mass spectrometer, the instrument having a magnetic section with a controllable electromagnetic field. Controlling the electromagnetic field is accomplished by controlling a temperature of a base plate within the magnetic section, by controlling a current passing through an electromagnetic coil disposed within the magnetic, by disposing a magnetic shunt across a portion of a yoke of the magnet, or by any of the above either independently or in combination. The magnetic shunt is configured to have a temperature coefficient of remnant flux density that is opposite the temperature coefficient of remnant flux density of a first pair of permanent magnets located within the magnetic section.

Abstract: A focal plane detector assembly of a mass spectrometer includes an ion detector configured to detect ions crossing a focal plane of the spectrometer and an electrically conductive mesh lying in a plane parallel to the focal plane, positioned such that ions exiting a magnet of the mass spectrometer pass through the mesh before contacting the ion detector. The mesh is maintained at a low voltage potential, relative to a circuit ground, which shields ions passing through the magnet from high voltage charges from other devices, such as microchannel plate electron multipliers. The mesh may be mounted directly to the magnet or positioned some distance away. The detector array may include any suitable device, including a faraday cup detector array, a strip charge detector array, or a CCD detector array.

Abstract: An integral gas chromatograph/mass spectrometer system is assembled by attaching a gas chromatograph assembly on one side and a mass spectrometer assembly on the other side of a master flange. The gas chromatograph assembly is accurately positioned on a holder board integrally connected to the master flange. The mass spectrometry assembly is accurately positioned on a base plate that is integrally connected to the master flange.

Abstract: A mass spectrometer suitable to measure both positive and negative particles, such as ions for example in a vacuum chamber. This spectrometer is provided with a turnable permanent magnet segment, which provides the gap of a yoke with adequate magnetic flux having the appropriate direction to separate the positive or the negative particles. Changing the polarity adjusts the flight path of the ions. Thus, negatively charged ions and positively charged ions will follow similar flight paths under opposite polarities, permitting the use of a single array of detectors. One or more coils may be used in place of or in addition to the turnable permanent magnet segment in order to provide the appropriate magnetic flux to the gap, and/or facilitate the turning process of the turnable magnet segment. The turnable magnet and/or the coils may be inside or outside the vacuum chamber.

Abstract: An analytical instrument, such as a mass spectrometer, the instrument having a magnetic section with a controllable electromagnetic field. Controlling the electromagnetic field is accomplished by controlling a temperature of a base plate within the magnetic section, by controlling a current passing through an electromagnetic coil disposed within the magnetic, by disposing a magnetic shunt across a portion of a yoke of the magnet, or by any of the above either independently or in combination. The magnetic shunt is configured to have a temperature coefficient of remnant flux density that is opposite the temperature coefficient of remnant flux density of a first pair of permanent magnets located within the magnetic section.

Abstract: A water management system removes water vapor from the analyte slug that is desorbed from the trap. The water management system includes a device having a passage through which the volatile organic chemicals and water pass, the passage being designed to remove water vapor by swirling action on the stream. The amount of water removed is more than can be accounted for by simple condensation. The invention also includes the adjustment of the temperature of the water management device during the sample concentration cycle to prevent undesired condensation prior to desorption.