Force magnetometer for reel-to-reel assessment of superconducting tapes
View Patent ↗An apparatus is provided for reel-to-reel assessment of superconducting tapes (for example, REBCO CC tape) at low temperatures (for example, less than or equal to 65K). For example, the apparatus may be a force magnetometer. The apparatus may include one or more reels and pulleys used to move the superconducting tape into and out of a cryostat. The apparatus may also include a permanent magnet or electromagnet provided at a low temperature proximate to the tape. The magnet induces screening currents in the tape. The apparatus may also include an electric motor used to drive movement of the tape relative to the magnet. A tension meter may be provided to measure a tension of the tape. Alternatively, a current provided to the motor may also be measured. The apparatus may be used to measure the critical current at various positions on the superconducting tape at the low temperatures.
1 . A method comprising:
moving a superconducting tape through a cryostat, wherein the cryostat includes a magnet or electromagnet, and wherein the superconducting tape is moved proximate to the magnet or electromagnet;
measuring a tension of the superconducting tape using a device; and
determining a critical current of the superconducting tape based on the measured tension without a current being injected into the superconducting tape.
2 . The method of claim 1 , wherein the device is a tensionmeter.
3 . The method of claim 1 , wherein a cryogenic agent is provided in the cryostat, and wherein a temperature of the cryostat is less than or equal to 65K.
4 . The method of claim 1 , wherein the superconducting tape is moved through the cryostat using one or more first pulleys.
5 . The method of claim 4 , further comprising:
rotating the superconducting tape using one or more second pulleys.
6 . The method of claim 4 , further comprising:
pressing the superconducting tape against the one or more first pulleys using a pressing pulley to avoid sliding of the superconducting tape.
7 . The method of claim 1 , wherein a magnetic field produced by the magnet or electromagnet is perpendicular to the superconducting tape.
8 . The method of claim 1 , further comprising:
unwinding the superconducting tape from a feed-reel; and
re-winding the superconducting tape over a take-reel after the superconducting tape exits the cryostat.
9 . The method of claim 1 , wherein a cryogenic agent is provided in the cryostat, and wherein the cryogenic agent comprises liquid helium.
10 . The method of claim 1 , wherein the magnet or electromagnet comprises a superconducting electromagnet.
11 . The method of claim 1 , wherein the device is at room temperature outside of the cryostat.
12 . The method of claim 1 , wherein the superconducting tape is moved through the cryostat using an electric motor.
13 . The method of claim 1 , wherein determining the critical current comprises determining the critical current at two or more positions along the superconducting tape.