Detection Technique
Helium is used as a tracer because it penetrates small leaks rapidly. Helium has also the property of being non-toxic, chemically inert, inexpensive to produce, and present in the atmosphere only in minute quantities (5 ppm). Typically a helium leak detector will be used to measure leaks in the range of 10−5 to 10−12 Pa·m3·s−1.
- A flow of 10−5 Pa·m3·s−1 is slightly less than 1 ml per minute at Standard conditions for temperature and pressure (STP).
- A flow of 10−13 Pa·m3·s−1 is slightly less than 3 ml per century at STP.
Read more about this topic: Helium Mass Spectrometer
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