Superconducting operating temperatures can be provided by {HEAD ~ a cryogenic container} refrigerated by {TAIL ~ a closed cycle cryogenic refrigerator}, a stored cryogen, or in space, a heat sink 
refrigerated by
Superconducting operating temperatures can be provided by { HEAD ~ a cryogenic container } refrigerated by { TAIL ~ a closed cycle cryogenic refrigerator } , a stored cryogen , or in space , a heat sink
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH