Analysis of Field Errors for LARP Nb$$_3$$ Sn HQ03 Quadrupole Magnet

Journal Article · Thu Jun 01 00:00:00 EDT 2017 · IEEE Transactions on Applied Superconductivity

DOI:https://doi.org/10.1109/TASC.2016.2633995· OSTI ID:1563935

Wang, Xiaorong ^[1]; Ambrosio, Giorgio ^[2]; Chlachidze, Guram ^[2]; DiMarco, Joseph ^[2]; Ghosh, Arup K. ^[3]; Holik, Eddie Frank ^[2]; Prestemon, Soren O. ^[1]; Sabbi, GianLuca ^[1]; Stoynev, Stoyan Emilov ^[2]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States)

The U.S. LHC Accelerator Research Program, in close collaboration with CERN, has developed three generations of high-gradient quadrupole (HQ) Nb₃Sn model magnets, to support the development of the 150 mm aperture Nb₃Sn quadrupole magnets for the High-Luminosity LHC. The latest generation, HQ03, featured coils with better uniformity of coil dimensions and properties than the earlier generations. We tested the HQ03 magnet at FNAL, including the field quality study. The profiles of low-order harmonics along the magnet aperture observed at 15 kA, 1.9 K can be traced back to the assembled coil pack before the magnet assembly. Based on the measured harmonics in the magnet center region, the coil block positioning tolerance was analyzed and compared with earlier HQ01 and HQ02 magnets to correlate with coil and magnet fabrication. Our study the capability of correcting the low-order non-allowed field errors, magnetic shims were installed in HQ03. Furthermore, the expected shim contribution agreed well with the calculation. For the persistent-current effect, the measured a4 can be related to 4% higher in the strand magnetization of one coil with respect to the other three coils. Lastly, we compare the field errors due to the inter-strand coupling currents between HQ03 and HQ02.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-05CH11231; AC02-07CH11359
• OSTI ID: 1563935
• Alternate ID(s): OSTI ID: 1336408
• Report Number(s): FERMILAB-PUB-16-564-TD; ark:/13030/qt9105t88b; TRN: US2000788
• Journal Information: IEEE Transactions on Applied Superconductivity, Vol. 27, Issue 4; ISSN 1051-8223
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
LARP
Nb3Sn quadrupole magnets
field quality