On Fri, 24 Jan 2020 10:42:18 -0800 (PST), "
wrote:

Helium will leak even in its gaseous state. Metalized Mylar balloons last much longer than latex, but they still fail far more quickly filled with helium than with air. The helium diffuses right through the material.

Hence the need for a helium leak detector mass spectrometer. Anyone
with this piece of equipment NEEDS a HLDMS to go with it.
--

No deal? No problem! :-D