Heater duty cycle (the active pressure control circuit) in recondensing superconducting magnet systems is monitored to determine total thermal system performance, to minimize non-zero boil-off operation, and to reduce maintenance costs. Undesirable conditions, such as a degrading cold head, plumbing leaks, and so forth, may be detected earlier by monitoring heater duty cycle. Appropriate service intervals may be determined and cryogen or helium losses may be reduced. The technique provides earliest possible identification of failures related to such variables, as well as, facilitates isolation of the root cause of the problem. Monitoring of heater duty cycle (energization time) offers advantages over the traditional approach of monitoring or alarming on low level in the cryogen (helium) vessel. The technique may provide for relying on observation of the effects of reduced cooling capacity, such as abnormal heater duty cycle, early enough in the failure cycle to prevent helium loss and equipment damage.

A tank for storing a cryo fuel in a vehicle with an internal storage container, an external container enveloping the internal container, and an electromagnetically switch selectable thermal bridge element which can produce or interrupt a heat conducting connection between the wall of the internal container and the wall of the external container. The thermal bridge element may be designed such that in the closed state a spatial contact area is formed between a receiving element of the thermal switch affixed to the internal container and an output element of the thermal switch affixed to the outer container. The receiving element may have a smaller thermal capacity and/or size than the output element. Either the thermal bridge or a second thermal bridge element may be adapted to cool the internal container.

A contamination resistant probe attachment device attaches over an opening in a top cover of a disc drive to couple a testing probe to the interior of the disc drive. The attachment device has a base for surrounding and attaching around the opening in the top cover in the disc drive and a centrally located aperture for communicating with an upwardly extending flexible tube. The flexible tube having a first and second end, the first end attaching to the base and a second end defining an engagement opening throughwhich a disc drive testing probe is inserted. Seals formed by the contamination resistant probe attachment device, the top cover and the testing probe form a resistant barrier between the interior environment of the disc drive and exterior environment of the disc drive, allowing for probe mediated testing to occur outside the confines of either a clean hood, dedicated clean room or any environment where the disc drive external environment is more contaminated than the internal environment of the disc drive.