2011 Particle Accelerator Conference - List of Authors (Guo, W.)

Paper	Title	Page
WEP017	Re-Examination of the NSLS-II Magnet Multipole Specifications	1531
	W. Guo, A.K. Jain, S. Krinsky, S. Seiler, J. Skaritka, C.J. Spataro BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy The NSLS-II magnet multipole specifications were determined based on analysis of nonlinear beam dynamics. The required field quality does not exceed what was specified for the existing third-generation light sources. While the prototype magnets have met these specifications, the magnets from mass production could potentially have bigger errors which exceed certain tolerances. In this paper we discuss the results of recent calculations to provide further insight into the acceptable range of the magnet multipoles based on the physics requirements.

WEP065	Multiobjective Dynamic Aperture Optimization at NSLS-II	1597
	L. Yang, W. Guo, S. Krinsky, Y. Li BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this paper we present a multiobjective approach to the dynamic aperture (DA) optimization. Taking the NSLS- II lattice as an example, we have used both sextupoles and quadrupoles as tuning variables to optimize both on-momentum and off-momentum DA. The geometric and chromatic sextupoles are used for nonlinear properties while the tunes are independently varied by quadrupoles. The dispersion and emittance are fixed during tunes variation. The algorithms, procedures, performances and results of our optimization of DA will be discussed and they are found to be robust, general and easy to apply to similar problems.

THP129	Emittance Reduction Approaches for NSLS-II	2363
	W. Guo, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy NSLS-II is a third generation light source that is under construction at the Brookhaven National Laboartory. The 3GeV 792m long 30-cell storage ring will be commissioned in 2014. The emittance is lowered from 2nm to 1nm by three 7m damping wigglers. This paper will discuss the future emittance reduction approaches for NSLS-II. One option is installing more damping wigglers; an alternative solution is to manipulate the damping partition by shifting the chromatic quadrupoles horizontally. Both methods can lower the emittance effectively; however, the second method does not occupy the user straights. When the quarupoles are moved, the orbit and thus the vacuum chamber need to be redesigned, and beam dynamics could be affected. In the paper we will compare the lattice properties for the two options, and address the potential issues.

THP135	Implementation of a DC Bump at the Storage Ring Injection Straight Section	2378
	G.M. Wang, R.P. Fliller, W. Guo, R. Heese, S.L. Kramer, B. Parker, T.V. Shaftan, C.J. Spataro, F.J. Willeke, L.-H. Yu BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The NSLS II beam injection works with two septa and four fast kicker magnets. The kicker power supplies each produce a two revolution periods pulsed field, 5.2μs half sine waveform, using ~5kV drive voltage. The corresponding close orbit bump amplitude is ~15mm. It is desired that the bump they produce is transparent to the users for top-off injection. However, high voltage and short pulse power supplies have challenges to maintain pulse-to-pulse stability and magnet-to-magnet reproducibility. To minimize these issues, we propose to implement a DC local bump on top of the fast bump to reduce the fast kicker strength by a factor of 2/3. This bump uses two ring corrector magnets plus one additional magnet at the septum to create a bump. Additionally, these magnets could provide a DC bump, which would simulate the effects of a movable septum on the store beam lifetime. This paper presents the detail design of this DC injection bump and related beam dynamics.

THP136	Short Pulse Generation by Laser Slicing at NSLSII	2381
	L.-H. Yu, A. Blednykh, O.V. Chubar, W. Guo, S. Krinsky, Y. Li, T.V. Shaftan, G.M. Wang, F.J. Willeke, L. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract DE-AC02-98CH10886. We propose an upgrade R&D project for NSLSII to generate sub-pico-second short x-ray pulses using laser slicing. In this paper we discuss the basic parameters for this system and present a specific example for a viable design and its performance. Since the installation of the laser slicing system into the storage ring will break the symmetry of the lattice, we demonstrate it is possible to recover the dynamical aperture to the original design goal of the ring.

THP189	Low Horizontal Beta Function in Long Straights of the NSLS-II Lattice	2471
	F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886 The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of maintaining three long straights with large horizontal beta function while providing the other 12 long straights with smaller horizontal beta function to optimize the brightness of insertion devices. Our study considers the possible linear lattice solutions as well as characterizing the nonlinear dynamics. Results are reported on optimizations of dynamic aperture required for good injection efficiency and adequate Touschek lifetime.

THP190	Additional Quadrupoles at Center of Long Straights in the NSLS-II Lattice	2474
	F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886 The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of installing additional quadrupoles at the center of selected long straight sections in order to provide two low-beta source locations for undulators. The required modification to the linear lattice is discussed as well as the preservation of adequate dynamic aperture required for good injection efficiency and adequate Touschek lifetime.

Paper

Title

Page

Re-Examination of the NSLS-II Magnet Multipole Specifications

1531

W. Guo, A.K. Jain, S. Krinsky, S. Seiler, J. Skaritka, C.J. Spataro
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The NSLS-II magnet multipole specifications were determined based on analysis of nonlinear beam dynamics. The required field quality does not exceed what was specified for the existing third-generation light sources. While the prototype magnets have met these specifications, the magnets from mass production could potentially have bigger errors which exceed certain tolerances. In this paper we discuss the results of recent calculations to provide further insight into the acceptable range of the magnet multipoles based on the physics requirements.

WEP065

Multiobjective Dynamic Aperture Optimization at NSLS-II

1597

L. Yang, W. Guo, S. Krinsky, Y. Li
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper we present a multiobjective approach to the dynamic aperture (DA) optimization. Taking the NSLS- II lattice as an example, we have used both sextupoles and quadrupoles as tuning variables to optimize both on-momentum and off-momentum DA. The geometric and chromatic sextupoles are used for nonlinear properties while the tunes are independently varied by quadrupoles. The dispersion and emittance are fixed during tunes variation. The algorithms, procedures, performances and results of our optimization of DA will be discussed and they are found to be robust, general and easy to apply to similar problems.

THP129

Emittance Reduction Approaches for NSLS-II

2363

W. Guo, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
NSLS-II is a third generation light source that is under construction at the Brookhaven National Laboartory. The 3GeV 792m long 30-cell storage ring will be commissioned in 2014. The emittance is lowered from 2nm to 1nm by three 7m damping wigglers. This paper will discuss the future emittance reduction approaches for NSLS-II. One option is installing more damping wigglers; an alternative solution is to manipulate the damping partition by shifting the chromatic quadrupoles horizontally. Both methods can lower the emittance effectively; however, the second method does not occupy the user straights. When the quarupoles are moved, the orbit and thus the vacuum chamber need to be redesigned, and beam dynamics could be affected. In the paper we will compare the lattice properties for the two options, and address the potential issues.

THP135

Implementation of a DC Bump at the Storage Ring Injection Straight Section

2378

G.M. Wang, R.P. Fliller, W. Guo, R. Heese, S.L. Kramer, B. Parker, T.V. Shaftan, C.J. Spataro, F.J. Willeke, L.-H. Yu
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The NSLS II beam injection works with two septa and four fast kicker magnets. The kicker power supplies each produce a two revolution periods pulsed field, 5.2μs half sine waveform, using ~5kV drive voltage. The corresponding close orbit bump amplitude is ~15mm. It is desired that the bump they produce is transparent to the users for top-off injection. However, high voltage and short pulse power supplies have challenges to maintain pulse-to-pulse stability and magnet-to-magnet reproducibility. To minimize these issues, we propose to implement a DC local bump on top of the fast bump to reduce the fast kicker strength by a factor of 2/3. This bump uses two ring corrector magnets plus one additional magnet at the septum to create a bump. Additionally, these magnets could provide a DC bump, which would simulate the effects of a movable septum on the store beam lifetime. This paper presents the detail design of this DC injection bump and related beam dynamics.

THP136

Short Pulse Generation by Laser Slicing at NSLSII

2381

L.-H. Yu, A. Blednykh, O.V. Chubar, W. Guo, S. Krinsky, Y. Li, T.V. Shaftan, G.M. Wang, F.J. Willeke, L. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract DE-AC02-98CH10886.
We propose an upgrade R&D project for NSLSII to generate sub-pico-second short x-ray pulses using laser slicing. In this paper we discuss the basic parameters for this system and present a specific example for a viable design and its performance. Since the installation of the laser slicing system into the storage ring will break the symmetry of the lattice, we demonstrate it is possible to recover the dynamical aperture to the original design goal of the ring.

THP189

Low Horizontal Beta Function in Long Straights of the NSLS-II Lattice

2471

F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of maintaining three long straights with large horizontal beta function while providing the other 12 long straights with smaller horizontal beta function to optimize the brightness of insertion devices. Our study considers the possible linear lattice solutions as well as characterizing the nonlinear dynamics. Results are reported on optimizations of dynamic aperture required for good injection efficiency and adequate Touschek lifetime.

THP190

Additional Quadrupoles at Center of Long Straights in the NSLS-II Lattice

2474

F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of installing additional quadrupoles at the center of selected long straight sections in order to provide two low-beta source locations for undulators. The required modification to the linear lattice is discussed as well as the preservation of adequate dynamic aperture required for good injection efficiency and adequate Touschek lifetime.