It is important to have a single grounding point in the experiment. To prevent low-impedance loops in ground circuits from causing interference as currents are induced in them. Ground loops can occur in cables, plumbing, and any other conducting path. The main NHMFL grounding point is the northeast corner of the laboratory.
One useful form of
ground loop prevention is the isolation transformer. Another method used
to prevent ground loops involves insulating plumbing for the vacuum pumps.
Similarly, cryostats are isolated by using insulating o-rings with clamps
between them and the metal hose that connects them to the helium-3 system.
Your probe may also be similarly isolated from the cryostat.