Patent ID: 7223972

Claim:
A mass spectrometer, comprising: a base plate; a vacuum housing comprising at least one wall and a vacuum flange configured to form a vacuum chamber, the vacuum flange sealingly coupled to the base; a first heating element located within a first portion of the base plate; a first temperature sensor located within a second portion of the base plate, the first portion separated from the second portion by an amount of base plate material; and a magnetic section supported on the base plate, the magnetic section including: a yoke having a main body, a first yoke end, and a second yoke end; a first permanent magnet coupled to the yoke proximate to the first yoke end; a second permanent magnet coupled to the second yoke end, wherein the second permanent magnet is spaced apart from the first permanent magnet to form a magnetic gap therebetween; a coil formed around at least a portion of the yoke, the coil configured to carry a current, wherein a magnetic flux is produced when the current passes through the coil; a magnetic sensor disposed in the vicinity of the magnetic gap to produce signals indicative of a measurement of the magnetic flux; and a controller in communication with the magnetic sensor and the coil, the controller configured to receive the signals indicative of the measurement of the magnetic flux from the magnetic sensor and to regulate the current passing through the coil to controllably maintain the magnetic flux within a desired range.