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Technical Information
A mass spectrometer leak detector consists of the following components:
A spectrometer tuned to detect the mass of helium
A vacuum system to maintain adequately low pressure in the spectrometer
A mechanical pump(s) to evacuate the part to be tested.
Valves that enable the various stages of the leak detection cycle, from
evacuation, to test, to venting
Amplifier and readout instrumentation that monitors spectrometer output signal
Electrical power supplies and controls that sequence valve's, protective circuits, etc.
Fixturing that attaches the part to be leak-tested to the leak testing equipment.
Figure 88 Magnetic Separation Principle
Our SIPD family of products is also sensitive to helium and is based on a patented
technology called Selective Ion Pump Detection (see the following figure). 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
A permeable quartz capillary
A heater coil that surrounds the quartz capillary
Electronics to process the signal
Display for access to leak rate and other unit function.
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Agilent Helium Leak Detector User Manual
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