| 摘要 |
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.
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