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DISPERSION TOLERANCE CALCULATION FOR NSLS-II.

Description: In this paper we discuss the effect on the emittance of the residual dispersion in the insertion devices. The dispersion in the straights could be generated by the lattice error, trim dipole, and insertion device. The effect on the emittance is examined, and the dispersion tolerances are given for the NSLS-11.
Date: June 25, 2007
Creator: LIN,F. & GUO, W.
Partner: UNT Libraries Government Documents Department

Flexibility in the Design of the NSLS-II Lattice

Description: The NSLS-II light source is a proposed 3 GeV storage ring, with the potential for ultra-low emittance [1]. The lattice design uses a 30 cell DBA structure with a periodicity of 15, with alternating long and short straight sections. All cells are tuned achromatic to maximize the emittance reduction achieved as damping wigglers are added to the ring. Recent optimization of the lattice consisted of increasing the number of possible hard X-ray beam ports using three pole wigglers, reducing the number of magnets (quadrupoles and sextupoles) and shifting the magnets to allow easier extraction of the photon beams. The impact of the reduction of magnets on the lattice flexibility will be presented in terms of the tuning range possible for the lattice parameters: tune, emittance, chromaticity, and beta function matching to user insertion devices (IDs). This flexibility is important for optimizing the lattice linear and nonlinear properties, the dynamic aperture, and its impact on beam lifetime, as well as matching the user source requirements and for value engineering of magnets and power supplies.
Date: May 4, 2009
Creator: Kramer,S.L. & Guo, W.
Partner: UNT Libraries Government Documents Department

Impact of High-Order Multipole Errors in the NSLS-II Quadrupoles and Sectupoles on Dynamic and Momentum Aperture

Description: Successful operation of NSLS-II requires sufficient dynamic aperture for injection, as well as momentum aperture for Touschek lifetime. We explore the dependence of momentum and dynamic aperture on higher-order multipole field errors in the quadrupoles and sextupoles. We add random and systematic multipole errors to the quadrupoles and sextupoles and compute the effect on dynamic aperture. We find that the strongest effect is at negative momentum, due to larger closed orbit excursions. Adding all the errors based on the NSLS-II specifications, we find adequate dynamic and momentum aperture.
Date: May 4, 2009
Creator: Nash,B. & Guo, W.
Partner: UNT Libraries Government Documents Department

MULTIOBJECTIVE DYNAMIC APERTURE OPTIMIZATION AT NSLS-II

Description: 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.
Date: March 28, 2011
Creator: Yang, L.; Li, Y.; Guo, W. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

Experimental study of the longitudinal instability for beam transport

Description: Theoretical model for beam longitudinal instability in a transport pipe with general wall impedance is considered. The result shows that a capacitive wall tends to stabilize the beam. The experimental study of the instability for a pure resistive-wall is presented, including the design parameters, setup and components for the experiment. 6 refs., 3 figs.
Date: January 1, 1990
Creator: Reiser, M.; Wang, J.G.; Guo, W.M. & Wang, D.X.
Partner: UNT Libraries Government Documents Department

ADDITIONAL QUADRUPOLES AT CENTER OF LONG STRAIGHTS IN THE NSLS-II LATTICE

Description: 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 paper, 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 in the same straight. 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. This paper discusses the possibility of producing two low-beta source locations for optimum brightness of undulators in the long straights of NSLS-II lattice by installing additional quadrupoles at the center. The linear optics is optimized to satisfy the requirements of lattice function and properties. Nonlinear optimization for a lattice with working point at (37.16, 17.22) is performed. Considering the magnets misalignment errors and physical apertures, we calculate the frequency maps and plot the tune footprint. The results show that the modified high-low beta function lattice can achieve a modest dynamic aperture in this preliminary study. Further work will continue to expand the dynamic aperture to meet the requirement of good injection efficiency and sufficient Touschek lifetime.
Date: March 28, 2011
Creator: Lin, F.; Bengtsson, J.; Guo, W.; Krinsky, S.; Li, Y. & Yang, L.
Partner: UNT Libraries Government Documents Department

LOW HORIZONTAL BETA FUNCTION IN LONG STRAIGHTS OF THE NSLS-II LATTICE

Description: 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 short 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 paper, 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 optimization of dynamic aperture required for good injection efficiency and adequate Touschek lifetime. This paper discusses dynamic aperture optimization for the NSLS-II lattice with alternate high and low horizontal beta function in the long straights, which is proposed for the optimization of the brightness of insertion devices. The linear optics is optimized to meet the requirements of lattice function and source properties. Nonlinear optimization for a lattice with working point at (37.18, 16.2) is performed. Considering the realistic magnets errors and physical apertures, we calculate the frequency maps and plot the tune footprint. The results show that the lattice with high-low beta function has adequate dynamic aperture for good injection efficiency and sufficient Touschek lifetime.
Date: March 28, 2011
Creator: Fanglei, L.; Bengtsson, J.; Guo, W.; Krinsky, S.; Li, Y. & Yang, L.
Partner: UNT Libraries Government Documents Department

NSLS-II Booster Acceptance Studies

Description: The NSLS-II is a state of the art 3 GeV synchrotron light source being developed at BNL. The injection system will consist of a 200 MeV linac and a 3 GeV booster synchrotron. The injection system must supply 7.3 nC every minute to satisfy the top off requirements. A large booster acceptance is necessary to have a high booster injection efficiency and alleviate the requirements on the linac gun. We also anticipate transverse stacking of bunches in the booster to increase the amount of charge that can be delivered. We present studies of the anticipated booster stay clear and the ramifications for injection efficiency and transverse stacking.
Date: May 4, 2009
Creator: Fliller III,R.; Guo, W.; Heese, R.; Li, Y. & Shaftan, T.
Partner: UNT Libraries Government Documents Department

NSLS-II Lattice Optimization with Damping Wigglers

Description: NSLS-II, the third-generation light source which will be built at BNL is designed and optimized for 3 GeV energy, ultra-small emittance and high intensity of 500 mA. It will provide very bright synchrotron radiation over a large spectral range from IR to hard X-rays. Damping wigglers (DWs) are deployed to reduce the emittance of 2 nm by factors of 2-4, as well as for intense radiation sources for users. The linear and nonlinear effects induced by the DWs are integrated into the lattice design. In this paper, we discuss the linear and nonlinear optimization with DWs, and present a solution satisfying the injection and lifetime requirements. Our approach could be applied to the other light sources with strong insertion devices.
Date: May 4, 2009
Creator: Guo,W.; Kramer, S.; Krinsky, S.; Li, Y.; Nash, B. & Tanabe, T.
Partner: UNT Libraries Government Documents Department

Coincidence Prompt Gamma-Ray Neutron Activation Analysis

Description: The normal prompt gamma-ray neutron activation analysis for either bulk or small beam samples inherently has a small signal-to-noise (S/N) ratio due primarily to the neutron source being present while the sample signal is being obtained. Coincidence counting offers the possibility of greatly reducing or eliminating the noise generated by the neutron source. The present report presents our results to date on implementing the coincidence counting PGNAA approach. We conclude that coincidence PGNAA yields: (1) a larger signal-to-noise (S/N) ratio, (2) more information (and therefore better accuracy) from essentially the same experiment when sophisticated coincidence electronics are used that can yield singles and coincidences simultaneously, and (3) a reduced (one or two orders of magnitude) signal from essentially the same experiment. In future work we will concentrate on: (1) modifying the existing CEARPGS Monte Carlo code to incorporate coincidence counting, (2) obtaining coincidence schemes for 18 or 20 of the common elements in coal and cement, and (3) optimizing the design of a PGNAA coincidence system for the bulk analysis of coal.
Date: November 10, 2002
Creator: gandner, R.P.; Mayo, C.W.; Metwally, W.A.; Zhang, W.; Guo, W. & Shehata, A.
Partner: UNT Libraries Government Documents Department

IMPLEMENTATION OF A DC BUMP AT THE STORAGE RING INJECTION STRAIGHT SECTION

Description: The NSLS II beam injection works with a DC septum, a pulsed septum and four fast kicker magnets. The kicker power supplies each produce a two revolution period pulsed field, 5.2 {micro}s half sine waveform, using {approx}5kA drive voltage. The corresponding close orbit bump amplitude is {approx}15mm. It is desired that the bump 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 implementing 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 storage ring corrector magnets plus one additional magnet at the septum to create a local bump. Additionally, these magnets could provide a DC bump to simulate the septum position effects on the store beam lifetime. This paper presents the detail design of this DC injection bump and related beam dynamics.
Date: March 28, 2011
Creator: Wang, G.M.; Shaftan, T.; Kramer, S.K.; Fliller, R.; Guo, W.; Heese, R. et al.
Partner: UNT Libraries Government Documents Department

Short pulse generation by laser slicing at NSLSII

Description: We discuss an upgrade R&D project for NSLSII to generate sub-pico-second short x-ray pulses using laser slicing. We discuss its basic parameters 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. There is a rapid growth of ultrafast user community interested in science using sub-pico-second x-ray pulses. In BNL's Short Pulse Workshop, the discussion from users shows clearly the need for a sub-pico-second pulse source using laser slicing method. In the proposal submitted following this workshop, NSLS team proposed both hard x-ray and soft x-ray beamlines using laser slicing pulses. Hence there is clearly a need to consider the R&D efforts of laser slicing short pulse generation at NSLSII to meet these goals.
Date: March 28, 2011
Creator: Yu, L.; Blednykh, A.; Guo, W.; Krinsky, S.; Li, Y.; Shaftan, T. et al.
Partner: UNT Libraries Government Documents Department

COLLECTIVE EFFECTS IN THE NSLS-II STORAGE RING.

Description: A new high-brightness synchrotron light source (NSLS-II) is under design at BNL. The 3-GeV NSLS-II storage ring has a double-bend achromatic lattice with damping wigglers installed in zero-dispersion straights to reduce the emittance below 1nm. In this paper, we present an overview of the impact of collective effects upon the performance of the storage ring. Subjects discussed include instability thresholds, Touschek lifetime and intra-beam scattering.
Date: June 25, 2007
Creator: KRINSKY,S.; BENGTSSON, J.; BERG, J.S.; BLASKIEWICZ, M.; BLEDNYKH, A.; GUO, W. et al.
Partner: UNT Libraries Government Documents Department

CONCEPTUAL DESIGN OF THE NSLS-II INJECTION SYSTEM.

Description: We present the conceptual design of the NSLS-II injection system [1,2]. The injection system consists of a low-energy linac, booster and transport lines. We review two different injection system configurations; a booster located in the storage ring tunnel and a booster housed in a separate building. We briefly discuss main parameters and layout of the injection system components.
Date: June 25, 2007
Creator: SHAFTAN,T.; ROSE, T.; PINAYEV, I.; HEESE, R.; BENGTSSON, J.; SKARITKA, J. et al.
Partner: UNT Libraries Government Documents Department