Magnet maintenance advice in the wake of COVID-19 restrictions.

2020/03/31

Due to the recent spread of the coronavirus (COVID-19) infection, we are aware that many institutions and facilities may be closing for an unknown period.

Unlike other equipment, NMR systems- specifically Super Conducting Magnets, cannot be simply switched off. Cryogen levels (liquid helium and liquid nitrogen) within the magnet need to be maintained to keep the magnet functioning.

JEOL always recommends a weekly nitrogen fill and a helium fill well before the minimum refill level is reached. However, we do appreciate that this may be or could become difficult in the near future.

Regards nitrogen, most magnets can in fact go two weeks between fills.
Minimum safe helium levels vary between magnets. We can advise on this if required.

Should the nitrogen not be maintained, eventually the helium consumption would rise significantly. Once the helium level drops below a critical point- either by lack of nitrogen or a delayed helium fill- the magnet will cease to be super-conducting and dump its energy, (a quench). Most of what cryogens remain can be quickly released as gas when this happens.

Although magnets are designed to cope with an unexpected quench, there is always the risk of mechanical damage should this happen. But in most cases the magnet could be reinstalled. This would however be at considerable cost and with lengthy down-time in the interim.

We would therefore ask that every effort is made to maintain the cryogen levels of the magnet.

If at some stage it becomes clear that this cannot be done, we would recommend that the magnet is de-energized in a controlled manner to prevent a quench.

We would need to advise on the minimum helium level to de-energization safely, which depends on the magnet type. This work needs to be done by JEOL engineer. Please contact us ASAP in this case.

Please contact your JEOL service team at your region as soon as possible if this is the case.