Appnote: High efficiency helium leak check

High efficiency helium leak check

Using Alicat Instruments in High Efficiency Helium Leak Check via Helium Mass Spectrometer Leak Detection (HMSLD)

The interior of a test article is connected to a mass spectrometer leak test apparatus. This is placed in a chamber. The chamber is evacuated through a connection to an Alicat PCD-30PSIA-D Dual Valve Absolute Pressure Controller.

The chamber is then refilled to slightly above atmospheric pressure, with helium. This provides a pure helium environment for testing leakage flow from the outside of the test article to its interior. The interior of the test article is evacuated by the leak test apparatus.


  • A stable, reproducible helium atmosphere is created around the test article.
  • Helium usage is reduced as compared to continuous flow systems.