3 ms·

There was some buzz years ago about using liquid nitrogen instead but I don’t know if it made it into widespread production https://www.wired.com/story/mri-mag

• nullc 2y ago
  Sounds like that's more about using a cryocooler to minimize the helium used-- but presumably that requires keeping the coils in a particularly hard vacuum to adequately insulate them. There is some research towards operating at liquid hydrogen temperatures -- but hydrogen has its own logistical challenges.