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Status of the NSLS-II Injection System Design

Description: The NSLS-II is a new ultra-bright 3rd generation 3 GeV light source that will be built at Brookhaven National Laboratory. Its design is well under way. The requirements for the compact injector complex, which will continuously provide 3 GeV electrons for top-off injection into the storage ring, are demanding: high reliability, relatively high charge and low losses. The injector consists of a linear accelerator, a full-energy booster, as well as transport lines, and an injection straight section. In this paper we give an overview of the NSLS-II injector, discuss its status, specifications, and the design challenges.
Date: June 23, 2008
Creator: Shaftan,T.
Partner: UNT Libraries Government Documents Department

SYNCHROTRON RADIATION MONITOR FOR NSLS BOOSTER.

Description: NSLS booster diagnostics consisted of tune measurement system, system for turn-by-turn measurement on the electron beam, and beam intensity monitor, which is not absolutely calibrated. We present design and implementation of synchrotron light monitor for the booster, which expands diagnostics capabilities. The system allows to measure an orbit, beam sizes and coupling of the electron beam along the ramp.
Date: November 4, 2005
Creator: PINAYEV, I. & SHAFTAN, T.
Partner: UNT Libraries Government Documents Department

VACUUM WINDOW DESIGN FOR HIGH-POWER LASERS.

Description: One of the problems in the high-power lasers design is in outcoupling of a powerful laser beam out of a vacuum volume into atmosphere. Usually the laser device is located inside a vacuum tank. The laser radiation is transported to the outside world through the transparent vacuum window. While considered transparent, some of the light passing through the glass is absorbed and converted to heat. For most applications, these properties are academic curiosities; however, in multi-kilowatt lasers, the heat becomes significant and can lead to a failure. The absorbed power can result in thermal stress, reduction of light transmission and, consequently, window damage. Modern optical technology has developed different types of glass (Silica, BK7, diamond, etc.) that have high thermal conductivity and damage threshold. However, for kilo- and megawatt lasers the issue still remains open. In this paper we present a solution that may relieve the heat load on the output window. We discuss advantages and issues of this particular window design.
Date: April 21, 2005
Creator: SHAFTAN, T.
Partner: UNT Libraries Government Documents Department

Proceedings of Pulsed Magnet Design and Measurement Workshop

Description: The goals of the Workshop are to assess the design of pulsed system at the NSLS-II and establish mitigation strategies for critical issues during development. The focus of the Workshop is on resolving questions related to the set-up of the pulsed magnet laboratory, on measuring the pulsed magnet's current waveforms and fields, and on achieving tight tolerances on the magnet's alignment and field quality.
Date: January 19, 2010
Creator: Shaftan, T.; Heese, R. & Ozaki,S.
Partner: UNT Libraries Government Documents Department

SIMULATIONS OF TRANSVERSE STACKING IN THE NSLS-II BOOSTER

Description: The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The linac needs to deliver 15 nC in 80 - 150 bunches to the booster every minute to achieve current stability goals in the storage ring. This is a very stringent requirement that has not been demonstrated at an operating light source. We have developed a scheme to transversely stack two bunch trains in the NSLS-II booster in order to alleviate the charge requirements on the linac. This scheme has been outlined previously. In this paper we show particle tracking simulations of the tracking scheme. We show simulations of the booster ramp with a stacked beam for a variety of lattice errors and injected beam parameters. In all cases the performance of the proposed stacking method is sufficient to reduce the required charge from the linac. For this reason the injection system of the NSLS-II booster is being designed to include this feature. The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The injectors must provide 7.5nC in bunch trains 80-150 bunches long every minute for top off operation of the storage ring. Top off then requires that the linac deliver 15nC of charge once losses in the injector chain are taken into consideration. This is a very stringent requirement that has not been demonstrated at an operating light source. For this reason we have developed a method to transversely stack two bunch trains in the booster while maintaining the charge transport efficiency. This stacking scheme has been discussed previously. In this paper we show the simulations of the booster ramp with a single bunch train in the booster. Then we give a brief overview of the stacking scheme. Following, we show the results of stacking two bunch trains ...
Date: March 28, 2011
Creator: Fliller III, R. & Shaftan, T.
Partner: UNT Libraries Government Documents Department

DESIGN OF BEAM TRANSFER LINES FOR THE NSLS II

Description: The NSLS-II light source which is a proposed facility to be built at Brookhaven National Laboratory utilizes two synchrotron accelerator rings: the booster and the Storage ring (SR). Designing the NSLS-11 injector we considered two options for the booster layout, where the rings either (a) share the same tunnel, but placed at different horizontal planes or (b) booster is located in a separate building. The booster which accepts beam from the linac, accelerates the electron beam to an energy of 3.0 GeV and the beam is extracted to the Booster to Storage Ring (BtS) transport line which transports the beam and injects it into the SR ring. The design procedure for each of the two options of the BtS line and other details about the optics and the magnetic elements of the line are presented in this paper.
Date: June 25, 2007
Creator: TSOUPAS,N.; ROSE, J.; PINAYEV, I.; SHAFTAN, T. & STELMACH, C.
Partner: UNT Libraries Government Documents Department

Beam Based Calibration of Slow Orbit Bump in the NSLS Booster

Description: The orbit bumps in NSLS booster are used to move the beam orbit within 2mm of the extraction septum aperture on a time scale of millisecond at extraction in order to reduce the requirement on the amplitude of the fast extraction kicker. This may cause charge losses since before extraction, the beam stays on the distorted orbit for thousands of revolutions. In order to find the optimal orbit bump setpoint, which brings the maximum distortion at the extraction position and minimum distortions everywhere else, we developed an extraction model and performed an experiment to validate it. Afterwards, the model was applied to optimize the extraction process.
Date: May 4, 2009
Creator: Yang, X.; Shaftan, T. & Rose, J.
Partner: UNT Libraries Government Documents Department

PHYSICS RESULTS OF THE NSLS-II LINAC FRONT END TEST STAND

Description: The Linac Front End Test Stand (LFETS) was installed at the Source Development Laboratory (SDL) in the fall of 2011 in order to test the Linac Front End. The goal of these tests was to test the electron source against the specifications of the linac. In this report, we discuss the results of these measurements and the effect on linac performance.
Date: May 20, 2012
Creator: P., Fliller R.; Gao, F.; Yang, X.; Rose, J.; Shaftan, T. & Piel, C
Partner: UNT Libraries Government Documents Department

Design of the NSLS-II Linac Front End Test Stand

Description: The NSLS-II operational parameters place very stringent requirements on the injection system. Among these are the charge per bunch train at low emittance that is required from the linac along with the uniformity of the charge per bunch along the train. The NSLS-II linac is a 200 MeV linac produced by Research Instruments Gmbh. Part of the strategy for understanding to operation of the injectors is to test the front end of the linac prior to its installation in the facility. The linac front end consists of a 100 kV electron gun, 500 MHz subharmonic prebuncher, focusing solenoids and a suite of diagnostics. The diagnostics in the front end need to be supplemented with an additional suite of diagnostics to fully characterize the beam. In this paper we discuss the design of a test stand to measure the various properties of the beam generated from this section. In particular, the test stand will measure the charge, transverse emittance, energy, energy spread, and bunching performance of the linac front end under all operating conditions of the front end.
Date: March 28, 2011
Creator: Fliller III, R.; Johanson, M.; Lucas, M.; Rose, J. & Shaftan, T.
Partner: UNT Libraries Government Documents Department

MODULATION OF LOW ENERGY BEAM TO GENERATE PREDEFINED BUNCH TRAINS FOR THE NSLS-II TOP-OFF INJECTION

Description: The NSLS II linac will produce a bunch train, 80-150 bunches long with 2 ns bunch spacing. Having the ability to tailor the bunch train can lead to the smaller bunch to bunch charge variation in the storage ring. A stripline is planned to integrate into the linac baseline to achieve this tailoring. The stripline must have a fast field rise and fall time to tailor each bunch. The beam dynamics is minimally affected by including the extra space for the stripline. This paper discusses the linac beam dynamics with stripline, and the optimal design of the stripline. A stripline is to be integrated in the linac to match the storage ring uniform bunch charge requirement, which simplifies the gun pulser electronics and looses the edge uniform requirement. It is located at low energy to lower the stripline power supply requirement and limit the dumped electron radiation. By turning off the stripline, the beam dynamics through linac is comparable with the baseline design. More advanced ideas can be explored. If a DC corrector along with the stripline is used, the core bunch trains gets kick from the stripline while the head and the tail of bunch train just gets a DC kick. The stripline power supply waveform is a single flat top waveform with fast rise and drop and the pulse length is {approx}200 ns long or 100 bunches, which may be easier from the power supply view point. We are also considering the bunch by bunch charge manipulation to match the storage ring uniform bunch charge distribution requirement. By modulating the flat top waveform at 250 MHz with adjustable amplitude, each the bunch center is either at 45 degree or 135 degree. Only the head or tail of the bunch is trimmed out. Although each bunch center deviation from ...
Date: March 28, 2011
Creator: Wang, G.M.; Cheng, W.X.; Shaftan, T.; Fliller, R.; Heese, R. & Rose, J.
Partner: UNT Libraries Government Documents Department

INSERTION DEVICES R AND Ds FOR NSLS-II.

Description: NSLS-II is a medium energy storage ring of 3GeV electron beam energy with sub-nm.rad horizontal emittance and top-off capability at 500mA. Damping wigglers will be used not only to reduce the beam emittance but also for broadband sources for users. Cryo-Permanent Magnet Undulators (CPMUs) are considered for hard X-ray linear device, and permanent magnet based Elliptically Polarized Undulators (EPUs) are for polarization control. Rigorous R&D plans have been established to pursue the performance enhancement of the above devices as well as building new types of insertion devices such as high temperature superconducting wiggler/undulators. This paper describes the details of these activities and discuss technical issues.
Date: June 25, 2007
Creator: TANABE,T.; HARDER, D.A.; RAKOWSKY, G.; SHAFTAN, T. & SKARITKA, J.
Partner: UNT Libraries Government Documents Department

Microbunching and Beam Break Up in DUV FEL Accelerator

Description: We present the results of electron beam longitudinal modulation studies in the DUV-FEL accelerator. For bunch length determination we used the 'zero-phasing' method, based on a measurement of the chirped electron bunch energy spectra. The measurements revealed a spiky structure in the longitudinal phase space [1]. A model based on space charge effect is considered [2] to explain of the obtained phenomena. The analysis of the energy spectra has shown a sensitivity of the structure to the electron beam peak current, energy and longitudinal non-uniformity of the RF gun drive laser. Analytical calculations have demonstrated a qualitative agreement with experimental observations. Several experiments have been made to compare with theory; measured results are reviewed in this paper. The obtained effect is briefly discussed in relation to high brightness accelerators.
Date: March 17, 2008
Creator: Shaftan, T.; Carr, L.; Loos, H.; Sheehy, B.; Graves, William S.; Huang, Z. et al.
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 INJECTION STRAIGHT DIAGNOSTICS

Description: The ultra-bright light source being developed by the NSLS-II project will utilize top-up injection and fine tuning of the injection process is mandatory. In this paper we present the diagnostics installed in the injection straight. Its use for commissioning and tuning of the injection cycle is also described. The NSLS-II storage ring will utilize a 9.3 meter long injection straight section shown in Fig. 1. Injection will be preformed with two septa (one pulsed, one DC) and four kickers. The stored beam will be shifted towards the pulsed septum up to IS mm and the nominal distance between centers of the injected and the bumped beam is 9.5mm. The NSLS-II beam position monitors will have turn-by-turn and first-turn capabilities and will be used for the commissioning and tuning the injection process. However, there are three additional BPMs and two beam intercepting OTR screens (flags) installed in the injection straight.
Date: March 28, 2011
Creator: Pinayev, I.; Blednykh, A.; Ferreira, M.; Fliller, R.; Kosciuk, B.; Shaftan, T.V. et al.
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

Beam Transport and Diagnostics for the NSLS-II Injection System

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, 3 GeV booster synchrotron, and associated transfer lines. The transport lines between the linac and booster (LtB) and the booster and storage ring (BSR) must satisfy a number of requirements. In addition to transporting the beam while maintaining the beam emittance, these lines must allow for commissioning, provide appropriate diagnostics, allow for the appropriate safety devices and in the case of the BSR line, provide a stable beam for top off injection. Appropriate diagnostics are also necessary in the linac and booster to complement the measurements in the transfer lines and to allow for fast commissioning. In this paper we discuss the design of the transfer lines for the NSLSII along with the incorporated diagnostics and safety systems. Necessary diagnostics in the linac and booster are also discussed.
Date: May 4, 2009
Creator: Fliller III,R.; Alforque, R.; Heese, R.; Meier, R.; Rose, J.; Shaftan, T. et al.
Partner: UNT Libraries Government Documents Department

Alternative Designs for the NSLS-II Injection Straight Section

Description: Brookhaven National Laboratory (BNL) is developing a state-of-the-art 3 GeV synchrotron light source, the NSLS-II [1]. The 9.3 meter-long injection straight section of its storage ring now fits a conventional injection set-up consisting of four kickers producing a closed bump, together with a DC septum and a pulsed septum. In this paper, we analyze an alternative option based on injection via a pulsed sextupole magnet. We discuss the dynamics of the injected and stored beams and, subsequently, the magnet's specifications and tolerances. We conclude by summarized the advantages and drawbacks of each injection scheme.
Date: May 4, 2009
Creator: Shaftan,T.; Heese, R.; Weihreter, E.; Willeke, F.; Rehak, M.; Meier, R. et al.
Partner: UNT Libraries Government Documents Department

Top-Off Safety Analysis for NSLS-II

Description: Top-off injection will be adopted in NSLS-II. To ensure no injected beam can pass into experimental beamlines with open photon shutters during top-off injection, simulation studies for possible machine fault scenarios are required. We compare two available simulation methods, backward (H. Nishimura-LBL) and forward tracking (A. Terebilo-SLAC). We also discuss the tracking settings, fault scenarios, apertures and interlocks considered in the analysis.
Date: May 4, 2009
Creator: Li,Y.; Casey, B.; Heese, R.; Hseuh, H.; Job, O.; Krinsky, S. et al.
Partner: UNT Libraries Government Documents Department

EXPERIMENTAL CHARACTERIZATION OF SEEDED FEL AMPLIFIER AT THE NSLS SDL.

Description: Experimental characterization of a near-IR FEL amplifier at the NSLS SDL is presented in this report. SASE was observed from 0.8-1 {micro}m with 5 orders of magnitude gain. We have experimentally demonstrated saturation of a laser seeded FEL amplifier and control of the FEL output by the seed laser. Nonlinear harmonics have also been explored. The FEL pulse length for the first three harmonics was experimentally characterized and the increase of the FEL pulse length with harmonic number was observed for the first time. Computer simulation confirmed that the observed wide spectrum of the laser seeded FEL is due to the positive chirp of the seed laser.
Date: August 21, 2005
Creator: WATANABE, T.; LIU, D.; MURPHY, J.B.; ROSE, J.; SHAFTAN, T.; TSANG, T. et al.
Partner: UNT Libraries Government Documents Department

AN EXPERIMENTAL TEST OF SUPERRADIANCE IN A SINGLE PASS SEEDED FEL.

Description: Superradiance and nonlinear evolution of a FEL pulse in a single-pass FEL were experimentally demonstrated at the National Synchrotron Light Source (NSLS) Source Development Laboratory (SDL). The experiment was performed using a 1.5 ps high-brightness electron beam and a 100fs Ti:Sapphire seed laser. The seed laser and electron beam interact in the 10 meter long NISUS undulator with a period of 3.89 cm. The FEL spectrum, energy and pulse length along the undulator were measured. FEL saturation was observed, and gain of more the 200 (relative to seed laser) was measured. Both FEL spectrum widening and pulse length shortening were observed; FEL pulses as short as 65 fs FWHM were measured. The superradiance and nonlinear evolution were also simulated using the numerical code GENESIS1.3 yielding good agreement with the experimental results.
Date: August 21, 2005
Creator: WATANABE, T.; LIU, D.; MURPHY, J.B.; ROSE, J.; SHAFTAN, T.; TSANG, T. et al.
Partner: UNT Libraries Government Documents Department

PERFORMANCE OF THE DIAGNOSTICS FOR NSLS-II LINAC COMMISSIONING

Description: The National Synchrotron Light Source II (NSLS-II) is a state of the art 3-GeV third generation light source currently under construction at Brookhaven National Laboratory. The NSLS-II injection system consists of a 200 MeV linac, a 3-GeV booster synchrotron and associated transfer lines. The transfer lines not only provide a means to deliver the beam from one machine to another, they also provide a suite of diagnostics and utilities to measure the properties of the beam to be delivered. In this paper we discuss the suite of diagnostics that will be used to commission the NSLS-II linac and measure the beam properties. The linac to booster transfer line can measure the linac emittance with a three screens measurement or a quadrupole scan. Energy and energy spread are measured in a dispersive section. Total charge and charge uniformity are measured with wall current monitors in the linac and transformers in the transfer line. We show that the performance of the diagnostics in the transfer line will be sufficient to ensure the linac meets its specifications and provides a means of trouble shooting and studying the linac in future operation.
Date: March 28, 2011
Creator: Fliller III, R.; Padrazo, D.; Wang, G.M.; Heese, R.; H.-C., Hseuh; Johanson, M. et al.
Partner: UNT Libraries Government Documents Department

Radiation Spectrum Statistics in a High-Gain Free-Electron Laser at 266 nm

Description: High Gain Harmonic Generation FEL is in operations at the DUV-FEL facility (BNL). During HGHG FEL characterization we have measured a set of data demonstrating basic properties of the FEL radiation and compared them with analytic calculations [1]. This paper describes continuation of characterization of the HGHG FEL radiation output, based on the spectral measurements. We discuss analysis of an experiment at which the tunability concept of a seeded FEL with a fixed seed wavelength has been verified [2]. During the experiment we recorded about 200 radiation spectra corresponding to different energy chirps in the electron beam. We have analyzed this set of spectral data to obtain statistical properties of HGHG radiation. Correlations and trends in the radiation spectrum at 266 nm have been observed and studied.
Date: December 14, 2005
Creator: Shaftan, T.; Sheehy, B.; Yu, L.H.; Murphy, J.B.; Krinsky, S.; Rose, J. et al.
Partner: UNT Libraries Government Documents Department