50 Hz losses in superconducting niobium-titanium

✍ Scribed by R.C Bentley; B Graham

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 159 KB
• Volume: 11
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(71)90013-0

✦ Synopsis

is ~IO-6A and occasionally 10-7A, with long term drifts of up to 10-SA.

In the potentiometer circuit of Figure 2 we use the galvanometer as a null detector with only sufficient current feedback to prevent the operating point X from jumping to the next valley of Figure 2(b). Final nulling is therefore done manually. The dual 20 ~2 control allows one to reduce the measuring currents 13 and 14 rapidly to zero to check on possible drift of the galvanometer. /3 and 14 are measured using the room temperature standard resistors Ro and a digital voltmeter with floating input, or the ratio of I3/14 is measured using resistors Ro and a four-terminal digital ratio meter. Unknown resistances Ru of ~10 -s 12 were measured to an accuracy of ~1"10 4 with 13< 10-2A, I° an accuracy which is consistent with the measured noise level.