There are many methods of leak detection, such as a bubble test or pressure drop test, but none can compete with the sensitivity and the ability to pinpoint a leak that a Helium leak checker can offer. Additionally, a helium instrument allows for both quantitative and qualitative measurements.
A helium or, more precisely, a Helium 4 leak detector is essentially a tuned mass spectrometer which detects this gas and has the further option of identifying Helium 3 (used in cryogenics) and hydrogen. The unit has appropriate pumps supplied making it portable, with only mains electricity required. The unit is extremely sensitive to helium.
Investigating leaks in these circumstances can involve both a qualitative and a quantitative approach and just as in vacuum applications a helium leak detector is essential. Depending on the specification, leaks rates below 10-6 mbar l/s are frequently required. Helium leak checkers with an ultimate sensitivity of 10-12 mbar l/s offer the most accurate solution.