You wouldn't believe how cold helium is. We use a double vaccum jacketed transfer pipe from the axillary dewars to the niobium magnet windings. the inner tube is where the helium flows, and the outer jacket we have liquid nitrogen.
Its better that it sees a 77 kelvin environment than a 300 kelvin environment. these pipes themselves cost 10K dollars a foot.

The magnets reach a field density of 40 telsa. a bit more than a MRI magnet. some of the vaccum engineers i know tell me that if take all of the vacuum and put it under atmospheric pressure you would squeeze it to the volume of a grain of sand. that is how Good these systems are. The actual technology takes a long time to discuss.