Test Results of Fast Decaying Current-Induced AC Losses in SHMS Superconducting Magnets at Jefferson Lab

Journal Article · Tue Feb 18 00:00:00 EST 2020 · IEEE Transactions on Applied Superconductivity

DOI:https://doi.org/10.1109/TASC.2020.2974850· OSTI ID:1618828

Sun, Eric ^[1]; Lassiter, Steven ^[1]; Ghoshal, Probir ^[1]; Fair, Ruben ^[1]; Brindza, Paul ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

The 11 GeV Super High Momentum Spectrometer (SHMS) of Hall C, part of the recent 12 GeV accelerator Upgrade at Jefferson Lab, was successfully commissioned in 2017. Fast current discharges of the SHMS Q2, Q3 quadrupoles and dipole superconducting magnets experienced some level of operational difficulty, during commissioning and normal operation. Measurements and analyses demonstrate that the fast current discharge leads to substantial AC losses in the conductor and subsequently triggers a quench-back effect. The details of the measurements and analyses have been reported previously. This paper focuses on the test results of the magnets using a reduced value of the protection dump resistor for each magnet to lower the current decay rate. Finally, the test results confirmed that the reduced dump resistances eliminated the quench-back effect for the SHMS Q2, Q3 and Dipole magnets, thus improving their cryogenic operability.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC05-06OR23177
• OSTI ID: 1618828
• Report Number(s): DOE/OR/23177--4773; JLAB-PHY--19-3055
• Journal Information: IEEE Transactions on Applied Superconductivity, Journal Name: IEEE Transactions on Applied Superconductivity Journal Issue: 4 Vol. 30; ISSN 1051-8223
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AC loss
eddy currents
fast discharge
quench-back
superconducting magnets