cryogenic coolant the dewar includes a reservoir for holding cryogenic fluid an optional wicking material a transfer tube between the reservoir and the htsc device and a vacuum space preferably a vent channel is adjacent the reservoir and provides an escape path for evaporating gas from the wick and or htsc device the vent channel preferably provides a feed back system as more cryogenic coolant is transferred via the transfer tube more cool gas is vented through the channel which cools the reservoir and thereby reduces the transfer a charging system may also be provided as a source of cryogenic coolant in the preferred embodiment the charging system comprises a relatively large reservoir for liquid nitrogen application_number US 9297693 A description the present invention comprises a novel device a portable container for holding a high temperature superconducting sensor a htsc sensor for detecting mri signals the present invention also comprises a novel charging station for introducing liquid nitrogen into the portable container the portable container and the charging station work together to enable using htsc sensors as detectors in mri procedures turning to the portable containers in detail fig1 a 1b 5a and 5b show views of a portable dewar container 10 of the present invention as shown in fig1 a the dewar container 10 comprises two elements 1 a generally cylindrical molded outer casing 12 having an integrally molded handle 13 along one side of the cylinder fig1 a 1b 5a and 5b and 2 a generally cylindrical dewar insert 14 shown in detail in fig1 e which.