A test where a helium mass spectrometer instrument is used to detect and locate small leaks. It typically uses a vacuum chamber in which a sealed part filled with Helium is contained. Helium leaks from the container, and the rate of leakge is detected by a mass spectrometer. Often used to test welds of pressure vessles.
Magnetic Inspection Laboratory, Inc. > Services > Nondestructive Testing (NDT) > Leak Testing (Helium)