Electromagnetic and Mechanical Analysis of the Coil Structure for the CLAS12 Torus for 12 GeV Upgrade

Journal Article · Thu Dec 18 00:00:00 EST 2014 · IEEE Transactions on Applied Superconductivity

DOI:https://doi.org/10.1109/TASC.2014.2382604· OSTI ID:1211610

Ghoshal, P. K. ^[1]; Pastor, O. ^[1]; Kashy, D. ^[1]; Schneider, W. ^[1]; Wiseman, M. ^[1]; Zarecky, M. ^[1]; Young, G. ^[1]; Rode, C. ^[1]; Elouadrhiri, L. ^[1]; Burkert, V. ^[1]

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

The torus magnet for the CLAS12 spectrometer is a 3.6 T superconducting magnet being designed and built as part of the Jefferson Lab 12 GeV Upgrade. The magnet consists of six coil case assemblies mounted to a cold central hub. The coil case assembly consists of an aluminum case and cover enclosing an epoxy vacuum impregnated coil pack. The coil pack consists of a 117 turn double-pancake winding wrapped with 2 layers of 0.635 mm thick copper cooling sheets. The coil case assembly is cooled by supercritical helium at 4.6 K. This report details the structural analysis of the coil case assembly and the assessment of the coil pack stresses. For the normal operation of the torus magnet, the coil case assembly was analyzed for cool down to 4.6 K and the Lorentz forces at normal operating current. In addition to the normal operating configuration, the coil case assembly was analyzed for Lorentz forces arising from coil misalignment and current imbalances. The allowable stress criteria for the magnet followed the approach of the ASME codes. Primary stresses were limited to the lesser of 2/3 times the yield strength or 1/3 times the ultimate tensile strength. Primary plus secondary stresses were limited to 3 times the primary stress allowable. The analysis was performed using ANSYS Maxwell to calculate the magneto-static loads and ANSYS Mechanical to calculate the stresses.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC05-06OR23177
• OSTI ID: 1211610
• Report Number(s): JLAB-ACE-14-1934; DOE/OR/23177-3152; TRN: US1500624
• Journal Information: IEEE Transactions on Applied Superconductivity, Vol. 25, Issue 3; ISSN 1051-8223
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
SSC cable
coil structure
load
shorting coil
force imbalance
conduction cooled
superconducting magnet
magnet quench protection
double pancake
torus coil