Yup. Helium is such a tiny thing it can diffuse through almost anything, and in MEMS oscillators which are supposed to be at a rock solid 32kHz, causes variance in the frequency eventually just “gumming” it up entirely and causing it to stop working.
If you want to know how and why, Applied Science did a video on it. Five years ago. Because that’s when this leak happened.
Yup. Most of the mems devices will essentially shut down the device if they go out of tolerance. This is a pretty common-knowledge fact among folks who work with large magnets, or with helium or hydrogen gas.
Funnily enough, it also happens with equipment microcontrollers which are unlikely to have a MEMS unit in them – for instance, any benchtop centrifuge made after the mid-90s will shut down, and I’m pretty sure those are still on quartz clocks. It also effects things like on-chip thermometers.
