IPAC2018 - List of Authors (Cheng, W.X.)

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
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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
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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
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WEPAF012	Improvements of NSLS-II X-ray Diagnostic Beamlines	1837
	W.X. Cheng, B. Bacha, B.N. Kosciuk, D. Padrazo Jr BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-SC0012704 There are two X-ray diagnostic beamlines (XDB) developed at NSLS-II storage ring to measure emittance, energy spread, and other machine parameters. The first beamline utilizes a soft bending magnet radiation has been in operation since 2014. The tungsten pinhole originally located in the air had corrosion issue. The beamline has been improved by extending the vacuum to the imaging system. The second X-ray pinhole beamline using three-pole wiggler (TPW) radiation has been constructed and commissioned recently. Energy spread is able to be precisely measured due to large dispersion at the source point. A gated camera is equipped with the new beamline to acquire profiles within one turn. Recent operation experience and beam measurements will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF012
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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

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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

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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)

WEPAF012

Improvements of NSLS-II X-ray Diagnostic Beamlines

1837

W.X. Cheng, B. Bacha, B.N. Kosciuk, D. Padrazo Jr
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-SC0012704
There are two X-ray diagnostic beamlines (XDB) developed at NSLS-II storage ring to measure emittance, energy spread, and other machine parameters. The first beamline utilizes a soft bending magnet radiation has been in operation since 2014. The tungsten pinhole originally located in the air had corrosion issue. The beamline has been improved by extending the vacuum to the imaging system. The second X-ray pinhole beamline using three-pole wiggler (TPW) radiation has been constructed and commissioned recently. Energy spread is able to be precisely measured due to large dispersion at the source point. A gated camera is equipped with the new beamline to acquire profiles within one turn. Recent operation experience and beam measurements will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF012

Export •

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