B-1 Magnetic Separation Principle - Agilent Technologies VS Series Operation Manual

VS Series Helium Mass Spectrometer Leak Detectors
Valves that enable the various stages of the leak detection cycle, from evacuation, to
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test, to venting
Amplifier and readout instrumentation that monitors spectrometer output signal
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Electrical power supplies and controls that sequence valve's, protective circuits, etc.
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Fixturing that attaches the part to be leak-tested to the leak testing equipment
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Our SIPD family of products is also sensitive to helium and is based on a patented
technology called Selective Ion Pump Detection (Figure B-2). The sensor technology
incorporates an ion pump connected to a quartz capillary tube and maintained under high
vacuum. This membrane is heated with a coiled platinum filament. Once heated, the
membrane becomes permeable to helium. As the partial pressure of helium in the ion pump
increases, so does the current draw of the ion pump. This current is proportional to the
pressure and is therefore representative of the helium at the test probe of the instrument.
A selective ion pump detector consists of the following:
An ion pump and controller
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A permeable quartz capillary
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A heater coil that surrounds the quartz capillary
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Electronics to process the signal
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Display for access to leak rate and othe
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B-2
Figure B-1 Magnetic Separation Principle
r unit functions