Cryogen
Safety
Note that superconducting NMR magnets
contain liquid helium
and liquid
nitrogen and are filled with these liquids on a regular
basis.Magnet Quench
The sudden boil-off of these cryogens (and loss
of magnetic field) is
called a quench. A quench
is an
extremely unlikely occurrence under normal
circumstances. However, please note the following:
- There will be a loud venting of the gases at the top of the magnet and a dense white fog.
- This vapour cloud will seek the highest point in the room as it warms and expands over 700 times in volume.
- Nothing can stop a magnet quench once it begins.
- There is a serious asphyxiation hazard so leave the room immediately, keeping underneath the vapour cloud if you can.
- Contact NMR or safety staff urgently (security if out of hours).
- Do not re-enter the room until NMR staff have given permission.