초록 ▼

A cryostat current lead design uses a relatively high (i.e., at room temperature) thermal and electrical conductiveity first tube at its top to minimize joule heating. A relatively low thermal and electrical conductivity second tube is disposed below the first tube and thermally insulates the curren

A cryostat current lead design uses a relatively high (i.e., at room temperature) thermal and electrical conductiveity first tube at its top to minimize joule heating. A relatively low thermal and electrical conductivity second tube is disposed below the first tube and thermally insulates the current lead to lesson the zero current loss. A superconductivity lead accomodating lower member is attached at the bottom of the second tube with strands of wire extending from the interior of the first tube to the interior of the lower member which preferably is a tube. Superconducting leads may be attached by lead-tin alloy (soft) solder at the outside of the lower member. The method of the present invention is the use of the current lead to provide electrical power to a device within the liquid helium bath of the cryostat. Preferably, the room temperature resistance of the lead is between 0.7 volts and 1.0 volts divided by the maximum current to be carried.

대표청구항 ▼

A current lead for carrying electrical current between room temperature and a cryogenic region containing liquid helium coolant, wherein said lead is cooled by the passage of cold vapor from said coolant through said lead and including: (a) an elongated, tubular first member adapted to extend from r

A current lead for carrying electrical current between room temperature and a cryogenic region containing liquid helium coolant, wherein said lead is cooled by the passage of cold vapor from said coolant through said lead and including: (a) an elongated, tubular first member adapted to extend from room temperature into the upper portion of said cryogenic region and having an upper end, a lower end, and an inside; (b) an elongated, tubular second member having an inside, a lower end, and an upper end which is joined to the lower end of said first member, said second member extending below said first member; (c) an elongated, tubular third member having an inside, a lower end, and an upper end which is joined to the lower end of said second member, said third member extending below said second member; (d) a plurality of wires having upper ends and lower ends and contained at least partially within said second member, said upper ends of said plurality of wires attached to the inside of said first member and said lower ends of said plurality of wires attached to the inside of said third member. The combination of a current lead for carrying current between room temperature and a cryogenic region and cooled by passage of cold gas from the cryogenic region through said current lead including: (a) an elongate relatively high thermal and electrically conductive hollow first member having an upper end and a lower end and allowing passage of the cold gas therethrough; (b) an elongate relatively low thermal and electrically conductive hollow second member fixed to said lower end of said first member and extending below said first member, said second member having an upper end and a lower end and allowing passage of the cold gas therethrough; and (c) relatively high thermal and electrically conductive wire including a plurality of strands and having a top end attached to the inside of said first member, said wire extending down through the inside of said second member for cooling by passage of the cold gas and adaptable to carry current to at least one superconducting lead electrically connected to said wire adjacent said bottom of said wire; and a cryostat having downwardly decreasing temperatures and a liquid coolant bath, and wherein said lower end of said first member is disposed at below 10°C. and wherein said first member extends from outside of said cryostat to inside of said cryostat. A method of using in combination a cryostat having downwardly decreasing temperatures and a liquid coolant bath and a current lead, said current lead including: (a) an elongate relatively high thermal and electrically conductive hollow first member having an upper end and a lower end and allowing passage of the cold gas therethrough; (b) an elongate relatively low thermal and electrically conductive hollow second member fixed to said lower end of said first member and extending below said first member, said second member having an upper end and a lower end and allowing passage of the cold gas therethrough; and (c) relatively high thermal and electrically conductive wire including a plurality of strands and having a top end attached to the inside of said first member, said wire extending down through the inside of said second member for cooling by passage of the cold gas and adaptable to carry current to at least one superconducting lead electrically connected to said wire adjacent said bottom of said wire; and wherein said first member is adapted to extend from outside of a cryogenic chamber to inside of a cryogenic chamber; comprising the steps of: inserting said current lead into a cryostat with downwardly decreasing temperatures and with said superconducting lead extending into a liquid coolant bath in said cryostat, said lower end of said first member disposed below 10°C. in the cryostat; and electrically connecting a power source to said first member to supply power to within said cryostat by way of said current lead.