Helium Sniff Testing is a useful technique to finely localize leaks on hermetic packages.

Because of their small size Helium atoms are able to penetrate package fine cracks. To proceed, the device is placed on the Mass Spectrometer inlet chamber, its punctured/opened side connected to the inlet. The interior of the package is then put under vacuum whereas its exterior stays at atmospheric pressure.

Helium is spread at a gentle flow using a small needle probe pin-pointing potential leak sites (welding, feedthrough, pigtail, sealant, etc ...). If the area is exhibiting a leak, the Helium penetrates into the package and is detected.

This method gives a precise localization of leak sites allowing, for example, to discriminate defective feedthroughs from good ones on a package.

The study is completed by a mapping of leak sites, which is of great assistance for Fluorescent Dye Penetrant analysis : it helps to organize the cross-sectioning scheme.

Sample positioned for Helium Sniff Testing