Mass Spectrometry
Of all instruments used for leak detection, the VIC tracer gas sensitive mass spectrometer leak detector is the most sensitive and most accurate device. It is easily calibrated, requires no operator judgement and its use is non-destructive to the test object.
The heart of the most sensitive and accurate instrument for detecting extremely small leaks is the mass spectrometer, which is used to measure the rate of flow of a tracer gas through leaks using vacuum, pressure or vacuum-pressure techniques. The mass spectrometer detects the tracer gas and converts it to an electrical signal proportional to the size of the leak. Helium is usually used as a tracer gas because of its unique combination of properties:
- Helium is extremely rare in the atmosphere, so there is little ambient “noise” to interfere with leak measurement
- Non-explosive, non-toxic, completely inert (no contamination of the tested product)
- Will not contaminate and desensitize its own detector as is common with detectors using other tracers
- Helium is a small, light molecule (mass 4) and will flow readily through extremely small leaks
Benefits of VIC Mass Spectrometer Leak Detection Over Other Testing Techniques
- VIC testing is not affected by typical manufacturing background noise levels whereas Ultrasonic stability is greatly changed
- VIC testing non-dependent on operator judgement whereas Water Immersion is dependent on operator training and variance
- VIC testing is unaffected by temperature changes whereas Thermoconductivity outputs change greatly to temperature fluctuations
- VIC testing is tracer gas specific and unaffected by other gases whereas Halogen sensors become contaminated and react to gases in the area
- VIC detection limits not as susceptible to variations of the cleanliness of the vacuum system whereas Residual Gas Analyzers sensitivity ranges are greatly reduced