Author: Sharma, S.K.
Paper Title Page
WEPGW102 Investigation on Mysterious Long-Term Orbit Drift at NSLS-II 2728
 
  • Y. Hidaka, W.X. Cheng, L. Doom, R.P. Fliller, G. Ganetis, J. Gosman, C. Hetzel, R.A. Hubbard, D. Padrazo Jr, B. Podobedov, J. Rose, T.V. Shaftan, S.K. Sharma, V.V. Smaluk, T. Tanabe, Y. Tian, G.M. Wang, C.H. Yu
    BNL, Upton, Long Island, New York, USA
  
  Funding: The study is supported by U.S. DOE under Contract No. DE-SC0012704.
Over a few months in 2018, we observed occasional episodes of relatively quick accumulation of correction strengths for the fast correctors (used by the fast orbit feedback) near Cell 4 (C04) region at NSLS-II Storage Ring. We immediately started investigating the problem, but the cause remained unclear. However, after coming back from the Fall shutdown, we experienced even faster drifts, at a rate of as much as 10 urad per day in terms of orbit kick angle accumulation. The risk of damage on the ring vacuum chambers by the continuing orbit drift without explanation eventually forced us to take emergency study shifts and temporarily lock out the C04 IVU beamline. After extensive investigation by many subsystem experts in Accelerator Division, ruling out many suspicious sources one by one, we were finally able to conclude the cause to be the localized ground motion induced by large temperature jumps of the utility tunnel right underneath the C04 straight section. We report the details of this incident. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW102  
About • paper received ※ 19 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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THPTS094 High Gradient Quadrupoles for Low Emittance Synchrtrons 4332
 
  • S.K. Sharma, T.V. Shaftan, V.V. Smaluk, C.J. Spataro, T. Tanabe, G.M. Wang
    BNL, Upton, Long Island, New York, USA
  • N.A. Mezentsev
    BINP SB RAS, Novosibirsk, Russia
  
  A new lattice design has been proposed recently based on a Complex-Bend concept [1,2] for low emittance syn-chrotrons. The dipoles of a standard DBA lattice are replaced in the Complex Bend by high-gradient (~ 450 T/m) quadrupoles interleaved between discrete dipoles. In another version of the Complex Bend [3] the high gradient quadrupoles are displaced transversely along the beam trajectory to generate the required dipole field. In the latter version the quadrupole strength is reduced to ~ 250 T/m for a lattice that will conform to the layout of the existing NSLS-II 3-GeV storage ring. In this paper we present conceptual designs of a Halbach permanent-magnet (PM) quadrupole, a hybrid PM quadrupole, and a superconducting quadrupole, that can produce the de-sired quadrupole strengths for the Complex Bend appli-cation. REFERENCES [1] T. Shaftan, V. Smaluk and G. Wang, ’The Concept of Com-plex Bend’, NSLS-II Tech note No. 276, Jan 2018. [2] G. Wang et al., ’Complex Bend: Strong-focusing magnet for low emittance synchrotrons’, Physical Review Accelerators and Beams, 21, 100703 (2018). [3] G. Wang et al., ’Complex Bend II’, paper submitted to Physi-cal Review Accelerators and Beams.

 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS094  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)