IPAC2018 - List of Authors (Li, Y.)

Paper	Title	Page
TUPMK018	Round Beam Studies at NSLS-II	1529
	Y. Hidaka, W.X. Cheng, Y. Li, T.V. Shaftan, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886. Instead of typical flat beam, some synchrotron light us-ers prefer round beam, i.e., with equal horizontal and vertical emittance, for various reasons (e.g., simplified optics, smaller fraction of photons getting discarded, better phase space match between photon and e-beam). Several future upgrade storage rings such as APS-U, ALS-U, and SLS-2 currently plan to operate in round beam mode. We report our beam study results on round beam operating at NSLS-II by driving linear difference cou-pling resonance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF010	Fast Glitch Detection of Coupled Bunch Instabilities and Orbit Motions	1829
	W.X. Cheng, B. Bacha, K. Ha, Y. Li BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 During high current operation at NSLS-II storage ring, vertical beam size spikes have been noticed. The spikes are believed due to ion instability associates with vacuum activities localized in the ring. A new tool has been developed using gated BPM turn-by-turn (TBT) data to detect beam centroid glitches. When one turn orbit deviates outside the predefined window, a global event will be generated. This allows synchronized data acquisition of TBT beam positions around the ring. Bunch by bunch data is acquired at the same time to analyze the possible coupled bunch instabilities (CBI). Besides CBI mainly due to ion bursts, fast orbit glitches have been captured with the new tool. Sources of the glitches can be identified.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF011	Developments of Bunch by Bunch Feedback System at NSLS-II Storage Ring	1833
	W.X. Cheng, B. Bacha, Y. Li BNL, Upton, Long Island, New York, USA D. Teytelman Dimtel, San Jose, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 Transverse bunch-by-bunch (BxB) feedback system has been constructed and in operation since the very beginning of NSLS-II storage ring commissioning. As the total beam current continues increasing in the past years, the system has been operating stable and reliable. Advanced BxB diagnostic functions have been developed using the system. Continuous tune measurement is realized with a diagnostic single bunch. Coupled bunch instability growth rate is able to be measured with the transient excitation. The BxB feedback system is also capable to excite a small fraction of total bunches for lattice measurement during high current operations. We present the most recent developments and operation experience on the BxB feedback system at NSLS-II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF011
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF017	Correction of ID-Induced Transverse Linear Coupling at NSLS-II	1856
	Y. Hidaka, Y. Li, T.V. Shaftan, T. Tanabe, Y. Tian, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886. Sizeable lifetime jumps have been observed sporadically since March 2016 at NSLS-II. These jumps were found to coincide with insertion device (ID) gap motions. Particularly, one of the in-vacuum undulators (IVUs) at Cell 17 was discovered to have large localized skew quadrupole component variation with gap. To allow the machine to operate stably in the low-emittance mode, a global coupling feedforward system has been recently implemented and successfully deployed. After installation of a new additional skew quadrupole, coupling compensation of this ID is now performed by a local coupling feedforward system. Furthermore, the maximum gap limit of all the existing IVUs has been decreased from 40 mm to 25 mm to limit the skew component variation during user operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Round Beam Studies at NSLS-II

1529

Y. Hidaka, W.X. Cheng, Y. Li, T.V. Shaftan, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886.
Instead of typical flat beam, some synchrotron light us-ers prefer round beam, i.e., with equal horizontal and vertical emittance, for various reasons (e.g., simplified optics, smaller fraction of photons getting discarded, better phase space match between photon and e-beam). Several future upgrade storage rings such as APS-U, ALS-U, and SLS-2 currently plan to operate in round beam mode. We report our beam study results on round beam operating at NSLS-II by driving linear difference cou-pling resonance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK018

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF010

Fast Glitch Detection of Coupled Bunch Instabilities and Orbit Motions

1829

W.X. Cheng, B. Bacha, K. Ha, Y. Li
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-SC0012704
During high current operation at NSLS-II storage ring, vertical beam size spikes have been noticed. The spikes are believed due to ion instability associates with vacuum activities localized in the ring. A new tool has been developed using gated BPM turn-by-turn (TBT) data to detect beam centroid glitches. When one turn orbit deviates outside the predefined window, a global event will be generated. This allows synchronized data acquisition of TBT beam positions around the ring. Bunch by bunch data is acquired at the same time to analyze the possible coupled bunch instabilities (CBI). Besides CBI mainly due to ion bursts, fast orbit glitches have been captured with the new tool. Sources of the glitches can be identified.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF011

Developments of Bunch by Bunch Feedback System at NSLS-II Storage Ring

1833

W.X. Cheng, B. Bacha, Y. Li
BNL, Upton, Long Island, New York, USA
D. Teytelman
Dimtel, San Jose, USA

Funding: Work supported by DOE contract No: DE-SC0012704
Transverse bunch-by-bunch (BxB) feedback system has been constructed and in operation since the very beginning of NSLS-II storage ring commissioning. As the total beam current continues increasing in the past years, the system has been operating stable and reliable. Advanced BxB diagnostic functions have been developed using the system. Continuous tune measurement is realized with a diagnostic single bunch. Coupled bunch instability growth rate is able to be measured with the transient excitation. The BxB feedback system is also capable to excite a small fraction of total bunches for lattice measurement during high current operations. We present the most recent developments and operation experience on the BxB feedback system at NSLS-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF011

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAF017

Correction of ID-Induced Transverse Linear Coupling at NSLS-II

1856

Y. Hidaka, Y. Li, T.V. Shaftan, T. Tanabe, Y. Tian, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: The study is supported by U.S. DOE under Contract No. DE-AC02-98CH10886.
Sizeable lifetime jumps have been observed sporadically since March 2016 at NSLS-II. These jumps were found to coincide with insertion device (ID) gap motions. Particularly, one of the in-vacuum undulators (IVUs) at Cell 17 was discovered to have large localized skew quadrupole component variation with gap. To allow the machine to operate stably in the low-emittance mode, a global coupling feedforward system has been recently implemented and successfully deployed. After installation of a new additional skew quadrupole, coupling compensation of this ID is now performed by a local coupling feedforward system. Furthermore, the maximum gap limit of all the existing IVUs has been decreased from 40 mm to 25 mm to limit the skew component variation during user operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)