Cryogenic Liquid


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 office hours).


  • Do not re-enter the room until NMR staff have given permission.

  • Using liquid Nitrogen for VT NMR experiments

    Please refer to the safety rules in the Department of Chemistry if handling liquid N2.