High-field quench behavior and dependence of hot spot temperature on quench detection voltage threshold in a Bi2Sr2CaCu2Ox coil
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Here, small insert coils have been built using a multifilamentary Bi2Sr2CaCu2Ox round wire, and characterized in background fields to explore the quench behaviors and limits of Bi2Sr2CaCu2Ox superconducting magnets, with an emphasis on assessing the impact of slow normal zone propagation on quench detection. Using heaters of various lengths to initiate a small normal zone, a coil was quenched safely more than 70 times without degradation, with the maximum coil temperature reaching 280 K. Coils withstood a resistive voltage of tens of mV for seconds without quenching, showing the high stability of these coils and suggesting that the quench detection voltage shall be greater than 50 mV to not to falsely trigger protection. The hot spot temperature for the resistive voltage of the normal zone to reach 100 mV increases from ~40 K to ~80 K with increasing the operating wire current density Jo from 89 A/mm-2 to 354 A/mm-2 whereas for the voltage to reach 1 V, it increases from ~60 K to ~140 K, showing the increasing negative impact of slow normal zone propagation on quench detection with increasing Jo and the need to limit the quench detection voltage to < 1 V. These measurements, coupled with an analytical quench model, were used to access the impact of the maximum allowable voltage and temperature upon quench detection on the quench protection, assuming to limit the hot spot temperature to <300 K.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1339972
- Alternate ID(s):
- OSTI ID: 1238900
- Report Number(s):
- FERMILAB-PUB-15-023-TD; 1509984
- Journal Information:
- Superconductor Science and Technology, Vol. 28, Issue 7; ISSN 0953-2048
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Numerical simulation of quench initiation and propagation in multi-filamentary Bi 2 Sr 2 CaCu 2 O x round wires at high magnetic fields
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journal | April 2019 |
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