Optimization of refrigerator-cooled current leads for superconducting devices

✍ Scribed by J. Gerhold

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 904 KB
• Volume: 16
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(76)90052-7

✦ Synopsis

Large superconducting apparatus are best cooled by directly coupled refrigerators. The input of high currents to the superconductors produces heat losses according to the Wiedemann-Franz law. It is well-known that the direct input losses can be reduced when the leads are precooled over their entire length by cold helium gas.

However, since the cooling gas through the leads cannot be used within the heat exchangers the refrigerator does not work to its full efficiency. Therefore indirect input losses arise. The evaluation of these indirect losses is discussed in detail in the paper. Furthermore it is shown that minimum total input losses can be achieved by adequate choice of the cooling gas flow rate through the leads. This seems of great practical importance since cooling costs are a main factor in the practical application of superconductors.