2011 Particle Accelerator Conference - List of Keywords (injection)

Paper	Title	Other Keywords	Page
MOOBS2	Status of High Intensity Effects in the Spallation Neutron Source Accumulator Ring	space-charge, coupling, resonance, collective-effects	17
	S.M. Cousineau ORNL, Oak Ridge, Tennessee, USA
	Funding: This research is supported by UT-Battelle, LLC for the U. S. Department of Energy under contract No. DE-AC05-00OR22725 The 248-meter Spallation Neutron Source (SNS) accumulator ring has accumulated up to 1.55·10¹⁴, 1 GeV protons. At this intensity, space charge effects contribute significantly to the beam dynamics. Here we present observations of space charge effects in the SNS ring, with emphasis on space charge effects and e-p instabilities.
	Slides MOOBS2 [3.704 MB]

MOOCN1	Status of the LHC Operations and Physics Program	luminosity, proton, vacuum, status	32
	S. Redaelli CERN, Geneva, Switzerland
	The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) has just completed a successful first year of operation. In 2010, the primary goal to achieved a peak luminosity of 10³²cm⁻²s⁻¹ at a 7 TeV centre-of-mass energy was achieved and the machine achieved safely and reliably routine operation in the multi-MJ regime. The good results of 2010 have laid a solid foundation towards the achievement of the primary physics goal to deliver an integrated luminosity of 1 fb⁻¹ in 2011. A fast and efficient LHC re-commissioning in 2011 lead already to a peak luminosity of 2.5×10³²cm⁻²s⁻¹ achieved in the fourth commissioning week. In this paper, the 2010 commissioning experience is reviewed and the present status and perspective are presented.
	Slides MOOCN1 [15.792 MB]

MOODS4	Dancing Bunches as van Kampen Modes	impedance, synchrotron, damping, proton	94
	A.V. Burov Fermilab, Batavia, USA
	Theory of van Kampen modes is applied to bunch longitudinal motion. Case of inductive impedance domination is studied in more details. Threshold for loss of Landau damping is found to be very sensitive to fine structure of the distribution function. Good agreement with the Tevatron's "dancing bunches" is obtained.
	Slides MOODS4 [0.408 MB]

MOP021	The MICE Muon Beamline and Induced Host Accelerator Beam Loss	target, factory, synchrotron, emittance	148
	A.J. Dobbs, A. Alekou, K.R. Long Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Funding: Science and Technology Facilities Council The international Muon Ionisation Cooling Experiment (MICE) is designed to provide a proof of principle of ionisation cooling to reduce the muon beam phase space at a future Neutrino Factory and Muon Collider. The MICE Muon Beam is generated by the decay of pions produced by dipping a cylindrical titanium target into the proton beam of the 800 MeV ISIS synchrotron at the Rutherford Appleton Laboratory, U.K. Studies of the particle rate in the MICE Muon Beamline and its relationship to induced beam loss in ISIS are presented, using data taken in Summer 2010. Using time-of-flight to perform particle identification estimates of muon rates are presented and related to induced beam loss.

MOP051	End-to-End Simulation of an Inverse Cyclotron for Muon Cooling	cyclotron, simulation, emittance, collider	193
	K. Paul, E. Cormier-Michel Tech-X, Boulder, Colorado, USA T. Hart, D.J. Summers UMiss, University, Mississippi, USA
	Funding: DOE Office of High-Energy Physics, SBIR DE-FG02-08ER85044 Neutrino factories and muon colliders require significant cooling of the muon beam. Most muon cooling channels are long and expensive single-pass structures, due to the difficulty injecting very large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problems associated with other circular cooling channels, and they can potentially provide substantial initial cooling of the beam. We present the first end-to-end (injection to extraction) simulations of an inverse cyclotron for muon cooling, performed with the particle-in-cell code VORPAL. We study the cooling capability of the device as well as potential limitations due to space charge effects and material interactions with the beam.

MOP082	Modeling a 10 GeV Laser-Plasma Accelerator with INF&RNO	plasma, laser, simulation, electron	250
	C. Benedetti, E. Esarey, W. Leemans, C.B. Schroeder LBNL, Berkeley, California, USA
	Funding: Work supported by the Office of Science, Office of High Energy Physics, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The numerical modeling code INF&RNO (INtegrated Fluid & paRticle simulatioN cOde, pronounced "inferno") is an efficient 2D cylindrical code to model the interaction of a short laser pulse with an underdense plasma. The code is based on an envelope model for the laser while either a particle-in-cell (PIC) or a fluid description can be used for the plasma. The effect of the laser pulse on the plasma is modeled with the time-averaged ponderomotive force. These and other features allow for a significant speedup compared to standard full PIC simulations while still retaining physical fidelity. A boosted Lorentz frame (BLF) modeling capability has been introduced within the fluid framework enhancing the performance of the code. An example of a 10 GeV laser-plasma accelerator modeled using INF&RNO in the BLF is presented.

MOP101	Numerical Study of Self and Controlled Injection in 3-Dimensional Laser-Driven Wakefields	plasma, simulation, laser, electron	286
	A.W. Davidson, R. Fenseca, C. Joshi, W. Lu, J.L. Martins, W.B. Mori, L.O. Silva UCLA, Los Angeles, California, USA
	Funding: DOE and NSF In plasma based accelerators (LWFA and PWFA), the methods of injecting high quality electron bunches into the accelerating wakefield is of utmost importance for various applications. Understanding how injection occurs in both self and controlled scenarios is therefore important. To simplify this understanding, we start from single particle motion in an arbitrary traveling wave wakefields, an electromagnetic structure with a fixed phase velocity(e.g., wakefields driven by non-evolving drivers), and obtain the general conditions for trapping to occur. We then compare this condition with high fidelity 3D PIC simulations through advanced particle and field tracking diagnostics. Numerous numerical convergence tests were performed to ensure the correctness of the simulations. The agreement between theory and simulations helps to clarify the role played by driver evolution on injection, and a physical picture of injection first proposed in * is confirmed through simulations. Several ideas, including ionization assisted injection, for achieving high quality controlled injection were also explored and some simulation results relevant to current and future experiments will be presented. *W. Lu et al., PRSTAB 10, 061301, 2007

MOP123	Colliding Pulse Injection Control in a Laser-Plasma Accelerator	laser, plasma, collider, controls	325
	C.G.R. Geddes, M. Chen, E. Esarey, W. Leemans, N.H. Matlis, D.E. Mittelberger, K. Nakamura, G.R.D. Plateau, C.B. Schroeder, C. Tóth LBNL, Berkeley, California, USA D.L. Bruhwiler, J.R. Cary, E. Cormier-Michel, B.M. Cowan Tech-X, Boulder, Colorado, USA
	Funding: This work is supported by the U.S. Department of Energy, National Nuclear Security Administration, NA-22, and in part by the Office of Science under Contract No. DE-AC02-05CH11231. Control of injection into a high gradient laser-plasma accelerator is presented using the beat between two ’colliding’ laser pulses to kick electrons into the plasma wake accelerating phase. Stable intersection and performance over hours of operation were obtained using active pointing control. Dependence of injector performance on laser and plasma parameters were characterized in coordination with simulations. By scanning the intersection point of the lasers, the injection position was controlled, mapping the acceleration length. Laser modifications to extend acceleration length are discussed towards production of tunable stable electron bunches as needed for applications including Thomson gamma sources and high energy colliders.

MOP159	Ionization-Induced Trapping in Laser-Plasma Accelerators and Synchrotron Radiation from the Betatron Oscillation	electron, laser, radiation, simulation	394
	M. Chen, E. Esarey, C.G.R. Geddes, W. Leemans, C.B. Schroeder LBNL, Berkeley, California, USA D.L. Bruhwiler, E. Cormier-Michel Tech-X, Boulder, Colorado, USA
	Funding: This work is supported by the U.S. DOE Office of High Energy Physics under Contract No. DE-AC02-05CH11231, and NNSA, NA-22, and used the computational resources of NERSC. Ionization injection into a laser wakefield accelerator is studied by multi-dimensional particle-in-cell (PIC) simulations. To obtain low energy spread beams we use a short region of gas mixture (H⁺N) near the start of the stage to trap electrons, while the remainder of the stage uses pure H and is injection-free. Effects of gas mix parameters, including concentration and length of the mixture region, on the final electron injection number and beam quality are studied. Two dimensional PIC simulations show the injected electron beam has filament structures in the plane perpendicular to the laser polarization direction in early time and this structure disappears later due to the betatron oscillation of the electrons in the wakefield. Synchrotron radiation from the accelerated electrons is calculated by a post processing code - Virtual Detector for Synchrotron Radiation (VDSR).

MOP166	Comissioning of a BPM system for the LNLS Booster to Storage Ring Transfer Line	booster, controls, monitoring, storage-ring	405
	F.H. Cardoso, S.R. Marques, X.R. Resende LNLS, Campinas, Brazil
	In order to increase the number of diagnostics and make possible studies of beam position effects in the injection efficiency, a beam position monitoring system was designed to equip the BTS (booster to storage ring) transfer line employing the long striplines BPMs. The log-ratio technique was applied using a commercial electronics module (LR-BPM) from Bergoz Instrumentation. Currently the system is integrated to the LNLS control system, database and ready to be used routinely during the injections. This work describes the system topology, details about the hardware and software, bench tests and measurements performed with electron beam. Future plans to improve the injection efficiency will also be presented.

MOP174	The Study and Implementation of Signal Processing Algorithm for Digital Beam Position Monitor	storage-ring, brilliance, betatron, extraction	414
	L.W. Lai, Z.C. Chen, Y.B. Leng, Y.B. Yan, G.S. Yang SSRF, Shanghai, People's Republic of China X. Yi SINAP, Shanghai, People's Republic of China
	Digital beam position monitor (DBPM) system is one of the most important beam diagnostic instruments generally used in modern accelerators. The performance of DBPM is mainly given by its digital signal processing algorithm. In order to find out a better solution for our new DBPM system, two algorithms have been designed and implemented on a commercial FPGA based DAQ module (ICS1554) to retrieve the turn-by-turn (TBT) data. The first algorithm is based on frequency mixing, and the second one on discrete Fourier transform (DFT). Laboratory tests show that the standard deviation of measured positions can be better than 1μm at 5 dBm with input signal stronger than 5 dBm for both algorithms. And on-line evaluation indicates that real beam motion can be observed correctly using either algorithm.

MOP183	First Measurements of a New Beam Position Processor on Real Beam at Taiwan Light Source	brilliance, betatron, controls, storage-ring	429
	P. Leban, A. Košiček I-Tech, Solkan, Slovenia P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo NSRRC, Hsinchu, Taiwan
	Libera Electron, Libera Brilliance and Libera Brilliance⁺ compose the electron beam position processors product family, which covers the needs of wide variety of the circular light source machines. The instruments deliver unprecedented possibilities for either building powerful single station solutions or architecting complex feedback systems. Compared to its predecessors (Libera Electron and Libera Briliance), the latest member of the family Libera Brilliance⁺ allows even more extensive machine physics studies to be conducted due to large data buffers and the new true turn-by-turn position calculation. It offers a large playground for custom- written applications with VirtexTM 5 and COM Express Basic module with Intel Atom N270 (x86) inside. First field tests of the new product were performed on real beam at Taiwan Light Source (TLS). The test setup, measurements and results are discussed in the paper.

MOP205	NSLS-II Injection Straight Diagnostics	vacuum, septum, kicker, diagnostics	477
	I. Pinayev, A. Blednykh, M.J. Ferreira, R.P. Fliller, B.N. Kosciuk, T.V. Shaftan, G.M. Wang BNL, Upton, Long Island, New York, USA
	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 the paper we present the diagnostics installed on the injection straight. Its usage for commissioning and tuning of the injection cycle is also described.

MOP210	Residual Gas Fluorescence Monitor at RHIC	ion, emittance, vacuum, heavy-ion	492
	T. Tsang, D.M. Gassner BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by U.S. Department of Energy under Contract No. DE-AC02-98CH10886. A residual gas fluorescence beam profile monitor at the relativistic heavy ion collider (RHIC) has successfully recorded vertical beam sizes of Au-ion beams from 3.85 to 100 GeV/n during the 2010 beam runs. Although the fluorescence cross section of Au-ion is sufficiently large, the low residual gas in a typical vacuum chamber of <10-9 torr produces necessary weak fluorescence photons. However, with adequate CCD exposure time, the vertical beam profiles are captured to provide an independent measurement of the RHIC beam size and emittance. This beam diagnostic technique, utilizing the Au-ion beam induced fluorescence from residual gas where hydrogen is still the dominant constituent in nearly all vacuum system, represents a step towards the realization of a truly noninvasive beam monitor for high-energy particle beams.

MOP211	NSLS-II RF Beam Position Monitor	controls, feedback, EPICS, storage-ring	495
	K. Vetter, J.H. DeLong, A.J. Della Penna, K.M. Ha, Y. Hu, B.N. Kosciuk, J. Mead, I. Pinayev, O. Singh, Y. Tian BNL, Upton, Long Island, New York, USA G.J. Portmann LBNL, Berkeley, California, USA J.J. Sebek SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. DOE under contract No. DE-AC02-98CH10886. An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPMs in ±0.1C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS.

MOP222	Operational Use of Ionization Profile Monitors in the Fermilab Main Injector	antiproton, proton, controls, vacuum	519
	D.K. Morris, P. Adamson, D. Capista, I. Kourbanis, T. Meyer, K. Seiya, D. Slimmer, M.-J. Yang, J.R. Zagel Fermilab, Batavia, USA
	Funding: Operated by the Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy. Ionization profile monitors (IPMs) are used in the Fermilab Main Injector (MI) for injection lattice matching and to measure transverse emittance of the beam during acceleration. The IPMs provide a periodic, non-destructive means for emittance measurements where other techniques are not applicable. As Fermilab is refocusing its attention on the intensity frontier, non-intercepting diagnostics such as IPMs are expected to become even more important. This paper gives an overview of the operational use of IPMs for emittance measurements and injection lattice matching measurements at Fermilab, and summarizes the future plans.

MOP263	Fast Orbit Feedback System for the LNLS Storage Ring	feedback, controls, storage-ring, synchrotron	597
	L. Sanfelici, F.H. Cardoso, D.D. Felix Ferreira, S.R. Marques, D.O. Tavares LNLS, Campinas, Brazil
	The Brazilian Synchrotron Light Laboratory (LNLS) is based on a 1.37 GeV storage ring, previously operated by means of a Slow Orbit Feedback System at a maximum rate of 1 correction every 3 seconds. Since photon flux stability is a key issue for light source users, a faster control system was envisaged to provide better beam stability. This work presents an overview of the hardware architecture and the preliminary results achieved with the implementation of a Fast Orbit Feedback System using commercial hardware. BPM signals are acquired in a distributed topology and sent through a deterministic EtherCAT network to a PXI controller, responsible for applying the SVD-based correction matrix multiplication and communicating with the accelerator control system; the calculated current setpoints are sent to the correctors’ power supplies through a second EtherCAT network. FPGA-based acquisition and actuation chassis perform pre-filtering and control on the digitized input and output signals, respectively.

MOP272	Radiation Dose Level in the SSRF during Normal Operation	radiation, monitoring, neutron, storage-ring	615
	X.J. Xu, P. Fei, R. Qin, W. Shen, X. Xia, D. Zhang, J.Z. Zhou SINAP, Shanghai, People's Republic of China
	Shanghai Synchrotron Radiation Facility (SSRF) has been commissioned since December 2007, and has been formally operated since May 2009. In order to ensure the radiation safety for staff members and publics, the radiation levels of the workplace, the environment and the staff are monitored through a real-time network of gamma and neutron monitors as well as through TLD passive dosimeters. This paper reports the results of the radiation monitoring. From these results, we found that the annual dose equivalents were good to meet the management values of SSRF.

MOP274	Beam Loss Monitors for NSLS-II Storage Ring	electron, shielding, radiation, dipole	621
	S.L. Kramer, P. Cameron BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed these levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. In order to measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber wall. This will be done using the Cerenkov light as charged particles transit an ultra-pure fused silica rod placed close to the inner edge of the VC. The length of rod will collect the light from many charged particles of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

MOP275	Beam Loss Control for the NSLS-II Storage Ring	controls, dipole, beam-losses, shielding	624
	S.L. Kramer, J. Choi BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region. * Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

MOP276	Applying Cascaded Parameter Scan to Study Top-off Safety in NSLS-II Storage Ring	simulation, photon, interlocks, storage-ring	627
	Y. Li, S.V. Badea, W.R. Casey, G. Ganetis, R. Heese, H.-C. Hseuh, P.K. Job, S. Krinsky, B. Parker, T.V. Shaftan, S.K. Sharma, L. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886 In this paper we introduce a new algorithm, the cascaded parameter scan method, to efficiently carry out the scan over magnet parameters in the safety analysis for the NSLS-II top-off injection. In top-off safety analysis, one must track particles populating phase space through a beamline containing magnets and apertures and clearly demonstrate that for all possible magnet settings and errors, all particles are lost on scrapers within the properly shielded region. In the usual approach, the number of tracking runs increases exponentially with the number of magnet settings. In the cascaded parameter scan method, the number of tracking runs only increases linearly. This reduction of exponential to linear dependence on the number of setpoints, greatly reduces the required computation time and allows one to more densely populate phase space and to increase the number of setpoints scanned for each magnet. An example of applying this approach to analyze an NSLS-II beamline, the damping wiggler beamline, is also given.

MOP284	A High Performance DAC / DDS Daughter Module for the RHIC LLRF Platform	LLRF, controls, luminosity, synchrotron	648
	T. Hayes, M. Harvey, G. Narayan, F. Severino, K.S. Smith, S. Yuan 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 RHIC LLRF upgrade is a flexible, modular system. Output signals are generated by a custom designed XMC card with 4 high speed digital to analog converters interfaced to a high performance field programmable gate array (FPGA). This paper discusses the hardware details of the XMC DAC board as well as the implementation of a low noise rf synthesizer with digital IQ modulation. This synthesizer also provides injection phase cogging and frequency hop rebucketing capabilities.

MOP297	A Bunch to Bucket Phase Detector for the RHIC LLRF Upgrade Platform	LLRF, feedback, controls, synchrotron	675
	K.S. Smith, M. Harvey, T. Hayes, G. Narayan, S. Polizzo, F. Severino 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 As part of the overall development effort for the RHIC LLRF Upgrade Platform, a 4 channel ADC daughter module was developed to provide high speed, wide dynamic range digitizing and processing of signals from DC to several hundred megahertz. The first operational use of this card was to implement the bunch to bucket phase detector for the RHIC LLRF beam control feedback loops. This paper will describe the design and performance features of this daughter module as a bunch to bucket phase detector, and also provide an overview of its place within the overall LLRF platform architecture as a high performance digitizer and signal processing module suitable to a variety of applications.

TUOBN1	Laser Wakefield Acceleration Beyond 1 GeV using Ionization Induced Injection	laser, electron, plasma, simulation	707
	K.A. Marsh, C.E. Clayton, C. Joshi, N. Lemos, W. Lu, W.B. Mori, A.E. Pak UCLA, Los Angeles, California, USA F. Albert, T. Doeppner, C. Filip, D.H. Froula, S.H. Glenzer, B.B. Pollock, D. Price, J.E. Ralph LLNL, Livermore, California, USA R.A. Fonseca, S.F. Martins Instituto Superior Tecnico, Lisbon, Portugal L.O. Silva IPFN, Lisbon, Portugal
	Funding: Supported by DOE Grants No. DE-AC52-07NA27344, DE-FG03-92ER40727, DE-FG02-92ER40727, DE-FC02-07ER41500, DE-FG52-09NA29552, NSF Grants No. PHY-0936266, PHY-0904039 and FCT, Por., No. SFRH/BD/35749/2007 A series of laser wakefield accelerator experiments leading to electron energy exceeding 1 GeV are described. Theoretical concepts and experimental methods developed while conducting experiments using the 10 TW Ti:Sapphire laser at UCLA were implemented and transferred successfully to the 100 TW Calisto Laser System at the Jupiter Laser Facility at LLNL. To reach electron energies greater than 1 GeV with current laser systems, it is necessary to inject and trap electrons into the wake and to guide the laser for more than 1 cm of plasma. Using the 10 TW laser, the physics of self-guiding and the limitations in regards to pump depletion over cm-scale plasmas were demonstrated. Furthermore, a novel injection mechanism was explored which allows injection by ionization at conditions necessary for generating electron energies greater than a GeV. The 10 TW results were followed by self-guiding at the 100 TW scale over cm plasma lengths. The energy of the self-injected electrons, at 3x10¹⁸ cm^-3 plasma density, was limited by dephasing to 720 MeV. Implementation of ionization injection allowed extending the acceleration well beyond a centimeter and 1.4 GeV electrons were measured.
	Slides TUOBN1 [2.488 MB]

TUOBS3	Status of the NSLS-II Project	vacuum, storage-ring, radiation, photon	732
	F.J. Willeke BNL, Upton, Long Island, New York, USA
	NSLS-II, the new 3 GeV 3rd generation light source presently under construction at Brookhaven National Laboratory will provide ultra-bright synchrotron radiation of 10²¹ photons s^-1 mm^-2 mrad^-2 0.1% BW^-1 at 2keV and high photon flux of 10¹⁵ photons s^-1 0.1% BW^-1. The facility will support a minimum of 60 beamlines. Construction started in 2009 and commissioning is expected to be completed in 2014. This report will provide a description of the NSLS-II design and will summarize the status of the construction project.
	Slides TUOBS3 [7.560 MB]

TUP190	Upgrade of the APS Booster Synchrotron Magnet Ramp	booster, dipole, controls, synchrotron	1181
	C. Yao, B. Deriy, G. Feng, H. Shang, J. Wang ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06-CH11357 The APS booster is a 7-GeV electron synchrotron with 0.5-second cycle time. Both voltage and current ramp modes were in the original design but only the voltage ramp has been commissioned. Two software-based ramp control programs are used to regulate the current waveform to a linear ramp. The system has been operated for user beam operations for many years. Some instability exists in the ramp correction that requires manual intervention from time to time by the operators. Sensitivity of magnet currents to external changes, such as AC line voltage, harmonic interference from the high-power rf system, etc., has been observed. In order to meet the increased single-bunch-charge requirement of the APS upgrade we need more flexible current ramps such as flat porches for injection and extraction and smooth transitions. Recent efforts to develop an energy-saving operation mode also call for ramp improvement. This paper presents test results of a workstation-based current regulation program and an FPGA-based implementation as a future upgrade.

TUP195	Commissioning the ALS Digital Power Supply Controller in the Booster Dipole and Quadrupole Magnet Power Supplies	booster, controls, power-supply, quadrupole	1190
	J.M. Weber, T. Scarvie, C. Steier, CA. Timossi LBNL, Berkeley, California, USA
	Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. A few years ago, the ALS was upgraded to achieve Top-Off Mode, which required replacing the booster dipole and quadrupole magnet power supplies to increase the peak booster beam energy from 1.5GeV to 1.9GeV. The original analog controller for each power supply has been replaced by a digital power supply controller (DPSC) to improve stability and resolution and provide a remote interface. The DPSC capabilities include 24-bit 100k-point digital reference waveform download and voltage reference generation, and complete digital current loop implementation. The hardware includes an FPGA with an embedded processor running a full EPICS IOC on VxWorks. This paper will present the current functionality of the DPSC as well as performance results from recent commissioning.

TUP202	Non-Scaling FFAG Proton Driver for Project X	proton, linac, focusing, synchrotron	1199
	C. Johnstone, D.V. Neuffer Fermilab, Batavia, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA L.J. Jenner, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom P. Snopok IIT, Chicago, Illinois, USA
	The next generation of high-energy physics experiments requires high intensity protons at multi-GeV energies. Fermilab’s HEP program, for example, requires an 8-GeV proton source to feed the Main Injector to create a 2 MW neutrino beams in the near term and would require a 4 MW pulsed proton beam for a potential Neutrino Factory or Muon Collider in the future. High intensity GeV proton drivers are difficult at best with conventional re-circulating accelerators, encountering duty cycle and space-charge limits in the synchrotron and machine size and stability concerns in the weaker-focusing cyclotrons. Only an SRF linac, which has the highest associated cost and footprint, has been considered. Recent innovations in FFAG design, however, have promoted another re-circulating candidate, the Fixed-field Alternating Gradient accelerator (FFAG), as an attractive, but as yet unexplored, alternative. Its strong focusing optics coupled to large transverse and longitudinal acceptances would serve to alleviate space charge effects and achieve higher bunch charges than possible in a synchrotron and presents an upgradeable option from the 2 MW to the 4 MW program.

TUP211	Compensation of Fast Kicker Rolls with Skew Quadrupoles	kicker, quadrupole, photon, coupling	1208
	I. Pinayev BNL, Upton, Long Island, New York, USA
	The development of the third generation light sources lead to the implementation of the top-up operation, when injection occurs while users collect data. The beam excursions due to the non-closure of the injection bump can spoil the data and need to be suppressed. In the horizontal plane compensation can be achieved by adjusting timing and kick amplitudes. The rolls of the kicker magnets create non-closure in the vertical plane and usually there is no means for correction. In the paper we describe proposed compensation scheme utilizing two skew quadrupoles placed inside the injection bump.

TUP213	Research and Development toward the RHIC Injection Kicker Upgrade	kicker, high-voltage, factory, impedance	1211
	W. Zhang, W. Fischer, H. Hahn, C. Pai, J. Sandberg, J.E. Tuozzolo 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. A research and development work is on going toward the upgrade of the RHIC Injection Fast Kicker System. We report here the proposed nano-second pulse generator, the initial test result, the options of the deflector design, injection pattern, and the benefit to the future RHIC programs.

TUP221	Helium Pressures in RHIC Vacuum Cryostats and Relief Valve Requirements from Magnet Cooling Line Failure	vacuum, simulation, dipole, quadrupole	1229
	C.J. Liaw, R. Than, J.E. Tuozzolo 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. A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results.

TUP222	Helium Release Rates and ODH Calculations from RHIC Magnet Line Cooling Line Failure	vacuum, simulation, controls, collider	1232
	C.J. Liaw, R. Than, J.E. Tuozzolo 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. A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

TUP232	Super-Conducting Wigglers and the Effect on Injection Efficiency	wiggler, simulation, storage-ring, betatron	1259
	M.J. Sigrist, L.O. Dallin, W.A. Wurtz CLS, Saskatoon, Saskatchewan, Canada
	The Canadian Light Source has two superconducting wigglers (SCW) operating at 2.1T and 4.3T peak fields. Injection efficiency into the storage ring is reduced by either device operating at high fields. Currently the CLS operates with a Fill and Decay mode, injecting with both wigglers at reduced field to avoid low injection efficiencies. Future implementation of a Top-up mode will require both wigglers to be operating at full field and better injection efficiencies will be required. Simulations and experiments have shown that the poor injection efficiency is related to operating a high vertical chromaticity. Much improved efficiencies are observed at when the chromaticity is lowered. As well, small improvements to the injection efficiency have been achieved through local correction of the beta-beats and tune shifts caused by the wigglers and optimisation of the injection co-ordinates of the injected beam. Measurements of the injection efficiencies at various chromaticities will be presented along with the betatron oscillations before and after correction.

TUP254	Real Time Monitoring of the Power Limit Resistor in the Boost Injection Kicker Power Supply	power-supply, booster, kicker, status	1301
	J.-L. Mi, J. Sandberg, Y. Tan, W. Zhang 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. After years of suffering Booster Injection Kicker transistor bank driver regulator trouble shooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can real time monitor the driver regulator power limit resistor status and warn machine operators if the power limit resistor changes values. This paper will introduce the power supply mainly and the new designed monitoring system.

TUP274	Oak Ridge National Laboratory Spallation Neutron Source Electrical Systems Availability and Improvements	kicker, extraction, pulsed-power, site	1337
	R.I. Cutler, D.E. Anderson, W.E. Barnett, J.D. Hicks, J.J. Mize, J. Moss, K. Norris, V.V. Peplov, K.R. Rust, J. T. Weaver ORNL, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS electrical systems have been operational for 4 years. System availability statistics and improvements are presented for ac electrical systems, dc and pulsed power supplies and klystron modulators

TUP282	The MICE Target	target, acceleration, extraction, proton	1355
	P.J. Smith, C.N. Booth, P. Hodgson, E. Overton, M. Robinson Sheffield University, Sheffield, United Kingdom G.J. Barber, K.R. Long Imperial College of Science and Technology, Department of Physics, London, United Kingdom E.G. Capocci, J.S. Tarrant STFC/RAL, Chilton, Didcot, Oxon, United Kingdom B.J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The MICE experiment uses a beam of low energy muons to test the feasibility of ionization cooling. This beam is derived parasitically from the ISIS accelerator at the Rutherford Appleton Laboratory. A target mechanism has been developed and deployed that rapidly inserts a small titanium target into the circulating proton beam immediately prior to extraction without undue disturbance of the primary ISIS beam. The first target drive was installed in ISIS during 2008 and operated successfully for over 100,000 pulses. A second upgraded design was installed in 2009 and after more than half a million actuations is still in operation. Further upgrades to the target design are now being tried in a separate test rig at the Rutherford Appleton Laboratory. The technical specifications for these upgraded designs are given and the motivations for the improvements are discussed. Additionally, further future improvements to the current design are discussed.

WEOBN1	Simultaneous Orbit, Tune, Coupling, and Chromaticity Feedback at RHIC	feedback, coupling, betatron, controls	1394
	M.G. Minty, A.J. Curcio, W.C. Dawson, C. Degen, R.L. Hulsart, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, P. Oddo, V. Ptitsyn, G. Robert-Demolaize, T. Russo, V. Schoefer, C. Schultheiss, S. Tepikian, M. Wilinski BNL, Upton, Long Island, New York, USA T. Satogata JLAB, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. All physics stores at the Relativistic Heavy Ion Collider are now established using simultaneous orbit, tune, coupling, and energy feedback during beam injection, acceleration to full beam energies, during the “beta-squeeze” for establishing small beam sizes at the interaction points, and during removal of separation bumps to establish collisions. In this report we describe the major changes made to enable these achievements. The proof-of-principle for additional chromaticity feedback will also be presented.
	Slides WEOBN1 [8.054 MB]

WEOBN6	LARP LHC 4.8 GHz Schottky System Initial Commissioning with Beam	pick-up, proton, controls, ion	1413
	R.J. Pasquinelli Fermilab, Batavia, USA F. Caspers, O.R. Jones CERN, Geneva, Switzerland A. Jansson ESS, Lund, Sweden
	The LHC Schottky system consists for four independent 4.8 GHz triple down conversion receivers with associated data acquisition systems. Each system is capable of measuring tune, chromaticity, momentum spread in either horizontal or vertical planes; two systems per beam. The hardware commissioning has taken place during the spring and summer of 2010. With nominal bunch beam currents of 10¹¹ protons, the first incoherent Schottky signals were detected and analyzed. This paper will report on these initial commissioning results. A companion paper will report on the data analysis curve fitting and remote control user interface of the system.
	Slides WEOBN6 [27.117 MB]

WEOBS3	The Effects of a Density Mismatch in a Two-State LWFA	electron, cavity, laser, ion	1421
	B.B. Pollock, F. Albert, C. Filip, D.H. Froula, S.H. Glenzer, J.E. Ralph LLNL, Livermore, California, USA C.E. Clayton, C. Joshi, K.A. Marsh, J. Meinecke, A.E. Pak, J.L. Shaw UCLA, Los Angeles, California, USA K.L. Herpoldt Oxford University, Physics Department, Oxford, Oxon, United Kingdom G.R. Tynan UCSD, La Jolla, California, USA
	Funding: Work performed under U.S. DOE Contract DE-AC52-07NA27344 and was partially funded by the Laboratory Directed Research and Development Program under project tracking code 06-ERD-056. A two-stage Laser Wakefield Accelerator (LWFA) has been developed, which utilizes the ionization induced injection mechanism to produce high energy, narrow energy spread electron beams when the electron density is equal in both stages. However, when the densities are not equal these high quality beams are not observed. As the electron density varies across the interface between the adjacent stages the size of the ion cavity is expected to change; this results in either a reduction of the peak electron energy (for a density decrease), or in the exclusion of previously trapped charge from the first wake period (for a density increase). The latter case can be overcome if the interaction length before the density interface exceeds a threshold determined by the densities in each stage, and may provide a mechanism for enhanced energy gain.

WEOCS2	Development of Nb3Sn 11 T Single Aperture Demonstrator Dipole for LHC Upgrades	dipole, collimation, magnet-design, multipole	1460
	A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, V. Kashikhin, A. Nobrega, I. Novitski Fermilab, Batavia, USA B. Auchmann, M. Karppinen, L. Rossi CERN, Geneva, Switzerland
	Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb3Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.
	Slides WEOCS2 [2.523 MB]

WEP015	Initial Simulations of Electron and Ion Beam Optics for the ANL EBIS Electron Collector	electron, ion, simulation, cathode	1525
	C. Dickerson, S.A. Kondrashev, P.N. Ostroumov ANL, Argonne, USA A.I. Pikin BNL, Upton, Long Island, New York, USA
	Funding: U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357 An Electron Beam Ion Source (EBIS) being developed at the Argonne National Laboratory (ANL) will be used to charge breed rare isotopes from a 1 Ci 252Cf source, the Californium Rare Isotope Breeder Upgrade (CARIBU). Simulations have been performed using commercially available software, TriComp, to ensure the electron collector is properly designed to dissipate the electron beam power and provide adequate acceptance for the injected ion beam.

WEP039	Tracking Stripped Proton Particles in SNS Ring Injection Momentum Dump Line	dipole, proton, simulation, collimation	1567
	J. G. Wang ORNL, Oak Ridge, Tennessee, USA
	3D computer simulations are performed to study magnetic field distributions and particle trajectories along the SNS ring injection momentum dump line. Optical properties and transfer maps along the dump line are calculated. The stripped proton particle distributions on the dump window are analyzed. The study has provided useful information for the redesign of the SNS ring injection beam dump.

WEP062	Optimized Sextupole Configurations for Sextupole Magnet Failure in Top-up Operation at the APS*	sextupole, lattice, power-supply, dynamic-aperture	1588
	V. Sajaev ANL, Argonne, USA
	Funding: Work supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Recently there was a situation at the APS when one sextupole power supply failed during top-up operation (all magnets at the APS have separate power supplies). The beam was not lost but the lifetime decreased significantly to the point where it was hard for the injectors to provide enough charge for top-up injections. Luckily, the power supply was able to reset quickly, and the operation was not compromised. One can anticipate similar failures in the future when it would not be possible to reset the power supply. In such a case, the APS would need to operate with lower lifetime until the next intervention period. Here we present an optimization of the sextupole distribution in the vicinity of the failed sextupole that allows us to partially recover the lifetime. A genetic optimization algorithm that involves simultaneous optimization of the dynamic and energy apertures was used. Experimental tests are also presented. M. Borland et al., "Application of Direct Methods of Optimizing Storage Ring Dynamic and Momentum Apertures," Proc. ICAP2009, to be published.

WEP094	Space Charge Measurements with a High Intensity Bunch at the Fermilab Main Injector	proton, simulation, emittance, space-charge	1648
	K. Seiya, B. Chase, J.E. Dey, P.W. Joireman, I. Kourbanis Fermilab, Batavia, USA A. Yagodnitsyna NSU, Novosibirsk, Russia
	Fermilab Main Injector will be required to operate with 3 times higher bunch intensity than today for Project X. The plan to study the space charge effects at the injection energy with intense bunches will be discussed.

WEP104	Transverse Feedback System and Instability Analysis at HLS	feedback, octupole, damping, resonance	1674
	J.H. Wang, Y.B. Chen, W. Li, L. Liu, M. Meng, B.G. Sun, L. Wang, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In this paper, we introduce the BxB transverse feedback systems at Hefei Light Source (HLS), which employ an analog system and a digital system. The experiment result of two systems. as well as the primary analysis of beam instability in HLS injection and operation are also presented in this paper.

WEP125	Higher-order Spin Resonances in 2.1 GeV/c Polarized Proton Beam	resonance, polarization, proton, betatron	1716
	M.A. Leonova, J. Askari, K.N. Gordon, A.D. Krisch, J. Liu, D.A. Nees, R.S. Raymond, D.W. Sivers, V.K. Wong University of Michigan, Spin Physics Center, Ann Arbor, MI, USA F. Hinterberger Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany V.S. Morozov JLAB, Newport News, Virginia, USA
	Funding: This research was supported by grants from the German Science Ministry Spin resonances can cause partial or full depolarization or spin-flip of a polarized beam. We studied 1st-, 2nd- and 3rd-order spin resonances with a 2.1 GeV/c vertically polarized proton beam stored in the COSY Cooler Synchrotron. We observed almost full spin-flip when crossing the 1st-order Ggamma=8−nu_y vertical-betatron-tune spin resonance and partial depolarization near some 2nd- and 3rd-order resonances. We observed almost full depolarization near the 1st-order Ggamma=8−nu_x horizontal spin resonance and partial depolarization near some 2nd- and 3rd-order resonances. Moreover, we found that a 2nd-order nu_x resonance seems about as strong as some 3rd-order nu_x resonances, while some 3rd-order nu_y resonances seem much stronger than a 2nd-order nu_y resonance. It was thought that, for flat accelerators, vertical spin resonances are stronger than horizontal, and lower order resonances are stronger than higher order ones. The data suggest that many higher-order spin resonances, both horizontal and vertical, must be overcome to accelerate polarized protons to high energies; the data may help RHIC to better overcome its snake resonances between 100 and 250 GeV/c.

WEP133	Adaptive Space-charge Meshing in the General Particle Tracer Code	space-charge, electron, simulation, brightness	1728
	S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands O.J. Luiten, M.J. de Loos TUE, Eindhoven, The Netherlands G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Efficient and accurate space-charge calculations are essential for the design of high-brightness charged particle sources. Space-charge calculations in the General Particle Tracer (GPT) code make use of an efficient multigrid Poisson solver developed for non-equidistant meshes at Rostock University. GPT uses aggressive mesh-adaptation with highly non-equidistant spacing to speed up calcula- tion time, where the mesh line positions are based upon the projected charge density. Here we present a new meshing scheme where the solution of an intermediate step in the multigrid algorithm is used to define optimal mesh line positions. An analytical test case and comparison with a molecular dynamics calculation of an ultrafast electron diffraction experiment demonstrate the capabilities of this new algorithm in the GPT code.

WEP136	Modelling of the EMMA ns-FFAG Ring Using GPT	space-charge, quadrupole, emittance, electron	1734
	R.T.P. D'Arcy UCL, London, United Kingdom J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in Aug 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10^-20 MeV. The injection line consists of a dogleg to extract the beam from ALICE, a matching section, and tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of forty two cells, each containing one focusing and one defocusing quadrupole. Commissioning of the EMMA ring started in late 2010. A number of different injection energy and bunch charge regimes are planned; for some of the regimes the effects of space charge may be significant. It is therefore necessary to model the electron beam transport in the injection line and the ring using a code capable of both calculating the effect of and compensating for space charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modelled for comparison with experimental results.

WEP149	Beam Measurement by a Wall Gap Monitor in ALPHA	linac, dipole, electron, extraction	1761
	T.H. Luo, P.D. McChesney, P.E. Sokol IUCF, Bloomington, Indiana, USA S.-Y. Lee IUCEEM, Bloomington, Indiana, USA
	In this report, we present our electron beam measurements with a wall gap monitor (WGM) in ALPHA injection and extraction beam lines. The WGM is first bench mark tested, and then installed in the ALPHA injection line to measure both the macro andμpulse of the injected beam and calibrate the beam current. By scanning the bending magnet before the WGM, and applying a demodulation signal processing scheme, we measured the tomography of the longitudinal phase space of the injected beam. We moved the WGM to extraction beam line and measured the properties of the extracted beam. By comparing the frequency spectrum of injected and extracted beam, we have confirmed the debunching performance of ALPHA.

WEP189	Compression and Synchronization of an Ultra-short Electron Beam Using a THz Undulator Interaction	undulator, laser, electron, radiation	1843
	J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To UCLA, Los Angeles, California, USA
	Funding: DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272 Injection of electron beams into laser driven picosecond scale accelerating structures demand highly synchronized electron beams with bunch lengths approaching the femtosecond scale. One-dimensional numerical studies of undulator interactions of 3.5 MeV sub-picosecond electron beams and THz pulse trains produced by optical rectification have shown substantial compression and a reduction in time of arrival jitter with respect to the accelerator drive laser from the scale of hundreds of fs to that of tens of fs. In this paper a THz undulator based compression and synchronization scheme is investigated.

WEP199	Estimation of Ecloud and TMCI Driven Vertical Instability Dynamics from SPS MD Measurements - Implications for Feedback Control	feedback, controls, simulation, synchrotron	1861
	O. Turgut, A. Bullitt, J.D. Fox, G. Ndabashimiye, C.H. Rivetta, M. Swiatlowski SLAC, Menlo Park, California, USA W. Höfle, B. Salvant CERN, Geneva, Switzerland R. Secondo LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). We present analysis of beam motion data obtained in high intensity SPS MD studies in 2009 and 2010. The single-bunch vertical E-cloud motion seen in parts of the bunch train after injection shows large tune shifts (roughly 0.02 above the 0.185 tune) developing between tail and head of unstable bunches. The unstable vertical motion has spectral content up to roughly 1.2 GHz and a quasi-periodic growth and decoherence relaxation oscillation effect is seen with time scales of hundred turns. Beam slice FFT and RMS techniques are illustrated to extract parameters important for the design of wide-band vertical feedback system, such as a growth rates of unstable motion, tune shifts within a single bunch and characterization of the bandwidth of the unstable structures within a bunch. We highlight the impact of synchrotron motion and injection transients on a proposed vertical processing channel. We present our MD plans including the beam driving process, developments in reduced model / identification techniques to extract dynamics from experimental and simulation data. *J. Fox et al., ‘‘SPS Ecloud Instabilities - Analysis Of Machine Studies And Implications For Ecloud Feedback,'' IPAC'10, WEPEB052

WEP201	Status of NSLS-II Booster	booster, extraction, dipole, septum	1864
	S.M. Gurov, A. Akimov, O. Anchugov, A.M. Batrakov, E.A. Bekhtenev, O.V. Belikov, P.B. Cheblakov, V.P. Cherepanov, A.D. Chernyakin, V.G. Cheskidov, I.N. Churkin, A.N. Dubrovin, A. Erokhin, K. Gorchakov, S.E. Karnaev, G.V. Karpov, V.A. Kiselev, V.V. Kobets, V.V. Kolmogorov, V.M. Konstantinov, A.A. Korepanov, E.A. Kuper, V. Kuzminykh, E.B. Levichev, V.R. Mamkin, A.S. Medvedko, O.I. Meshkov, N. Nefedov, V.V. Neyfeld, I.N. Okunev, M. Petrichenkov, V.V. Petrov, A. Polyansky, D.N. Pureskin, A. Rakhimov, S.I. Ruvinsky, T.V. Rybitskaya, L.M. Schegolev, A.V. Semenov, D.V. Senkov, S.S. Serednyakov, S.V. Shiyankov, D.A. Shvedov, S.V. Sinyatkin, V.V. Smaluk, A.V. Sukhanov, L. Tsukanova, A.V. Utkin, K. Yaminov BINP SB RAS, Novosibirsk, Russia J.H. DeLong, R.P. Fliller, G. Ganetis, H.-C. Hseuh, I. Pinayev, T.V. Shaftan, S.K. Sharma, O. Singh, Y. Tian, F.J. Willeke BNL, Upton, Long Island, New York, USA P.A.E. Elkiaer Danfysik A/S, Jyllinge, Denmark
	The National Synchrotron Light Source II is a third generation light source under construction at Brookhaven National Laboratory. The project includes a highly optimized 3 GeV electron storage ring, linac pre-injector and full-energy booster-synchrotron. Budker Institute of Nuclear Physics builds booster for NSLS-II. The booster should accelerate the electron beam continuously and reliably from minimal 170 MeV injection energy to maximal energy of 3.15 GeV and average beam current of 20 mA. The booster shall be capable of multi-bunch and single bunch operation. This paper summarizes the status of NSLS-II booster and the main designed parameters.

WEP204	An FFAG Accelerator for Project X	proton, lattice, linac, dynamic-aperture	1867
	D.V. Neuffer, L.J. Jenner, C. Johnstone Fermilab, Batavia, USA J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	The next generation of high-energy physics experiments requires high intensity protons in the multi-GeV energy range for efficient production of secondary beams. The Fermilab long-term future requires an 8 GeV proton source to feed the Main Injector for a 2 MW neutrino beam source in the immediate future and to provide 4 MW pulsed proton beam for a future neutrino factory or muon collider. We note that a 3GeV cw linac matched to a 3–8 GeV FFAG ring could provide beam for both of these mission needs, as well as the cw 3 GeV experiments, and would be a natural and affordable scenario. We present details of possible scenarios and outline future design and research directions.

WEP205	A Gap Clearing Kicker for Main Injector	kicker, booster, controls, simulation	1870
	I. Kourbanis, P. Adamson, J. Biggs, B.C. Brown, D. Capista, C.C. Jensen, G.E. Krafczyk, D.K. Morris, D.J. Scott, K. Seiya, S.R. Ward, G.H. Wu, M.-J. Yang Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Fermilab Main Injector has been operating at high Beam Power Levels since 2008 when multi-batch slip stacking became operational. In order to increase the beam power even further we have to address the localized beam loss due to beam left over in the Injection Kicker Gap during slip stacking. A set of Gap Clearing Kickers that kick any beam left in the injection gap to the beam abort have been installed during the summer of 2009 and became operational in October 2010. The kicker performance and its effect on beam losses will be described.

WEP206	An Accumulator/Pre-Booster for the Medium-Energy Electron Ion Collider at JLab	booster, ion, emittance, proton	1873
	B. Erdelyi, S. Abeyratne Northern Illinois University, DeKalb, Illinois, USA Y.S. Derbenev, G.A. Krafft, Y. Zhang JLAB, Newport News, Virginia, USA S.L. Manikonda, P.N. Ostroumov ANL, Argonne, USA
	Future nuclear physics facilities such as the proposed electron ion collider (MEIC) will need to achieve record high luminosities in order to maximize discovery potential. Among the necessary ingredients is the ability to generate, accumulate, accelerate, and store high current ion beams from protons to lead ions. One of the main components of this ion accelerator complex for MEIC chain is the accumulator that also doubles as a pre-booster, which takes 200 MeV protons from a superconducting linear accelerator, accumulates on the order of 1A beam, and boosts its energy to 3GeV, before extraction to the next accelerator in the chain, the large booster. This paper describes its design concepts, and summarizes some preliminary results, including linear optics, space charge dynamics, and spin polarization resonance analysis.

WEP207	Progress Towards A Novel Compact High Voltage Electrostatic Accelerator	high-voltage, vacuum, proton, tandem-accelerator	1876
	P. Beasley, O. Heid Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany
	A proof-of-principle demonstrator system has been successfully built and tested. It is based on a Cockcroft-Walton (or Greinacher) cascade but has been developed using a different design philosophy and using modern materials. This can then enable this compact accelerator configuration to operate at much higher voltage gradients. This paper explores the progress made to-date and future plans to utilize the technology to develop one such concept for an energy efficient 10 MV, 100 microamp, tandem proton accelerator, with less than a 2 square meter footprint .

WEP232	A Multi Megawatt Ring Cyclotron to Search for CP Violation in the Neutrino Sector	extraction, cyclotron, cavity, proton	1924
	L. Calabretta, M.M. Maggiore, D. Rifuggiato INFN/LNS, Catania, Italy A. Calanna CSFNSM, Catania, Italy L.A.C. Piazza INFN/LNL, Legnaro (PD), Italy
	A new approach to search for CP violation in the neutrino sector* is proposed by the experiment called DAEδALUS (Decay At rest Experiment for cp At Laboratory for Underground Science). DAEδALUS needs three sources of neutrino fluxes, each one located at 1.5, 8 and 20 km from the underground detector. Each source has to be supplied with a proton beam with power higher than 1, 2 and 5 MW respectively. Here we present the study for a Superconducting Ring Cyclotron able to accelerate the H²⁺ molecules and to deliver proton beam with maximum energy of 800 MeV and the required power. Although the average power for the first 2 sites are 1 and 2 MW, the 20% duty cycle, required by the experiment, has the consequence that the peak power should stay in the range 5-10 MW and a peak current of about 4.5 mA of H²⁺ is necessary. We present the parameters of the superconducting magnetic sector simulated by the code TOSCA, the isochronous magnetic field produced and the magnetic forces acting on the coils. Some evaluation on the feasibility of the ring cyclotron, the advantages and problems relates with acceleration of the H²⁺ molecules will be also presented. * J. Alonso et al., “Expression of Interest for a Novel Search for CP Violation in the Neutrino Sector: DAEδALUS”, Jun 2010. e-Print: arXiv:1006.0260

WEP234	Longitudinal Dynamics in the EMMA ns-FFAG	acceleration, induction, extraction, resonance	1927
	J.M. Garland, H.L. Owen UMAN, Manchester, United Kingdom N. Bliss STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom J.A. Clarke, N. Marks, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Work supported by the Science and Technology Facilities Council UK. Grant Number: ST/G004277/1 EMMA is the first non-scaling FFAG to be constructed, whose use of linear magnets means that the accelerating electron bunch rapidly crosses many resonances. We have modeled the capture and acceleration of bunches in the serpentine channel created by the radio-frequency cavities, and compare it to a proposed experiment in which induction cells allow slow acceleration. Two induction cores each providing ~20kV over 1.65 μs enable a number of resonance crossing experiments.

WEP242	Project X Functional Requirements Specification	linac, proton, collider, kaon	1936
	S.D. Holmes, S. Henderson, R.D. Kephart, J.S. Kerby, C.S. Mishra, S. Nagaitsev, R.S. Tschirhart Fermilab, Batavia, USA
	Funding: Work supported by the Fermi Research Alliance, under contract to the U.S. Department of Energy Project X is a multi-megawatt proton facility being designed to support intensity frontier research in elementary particle physics, with possible applications to nuclear physics and nuclear energy research, at Fermilab. A Functional Requirements Specification has been developed in order to establish performance criteria for the Project X complex in support of these multiple missions. This paper will describe the Functional Requirements for the Project X facility and the rationale for these requirements.

WEP261	Performance of the New EBIS Preinjector	ion, booster, linac, rfq	1966
	J.G. Alessi, E.N. Beebe, S. Binello, C.J. Gardner, O. Gould, L.T. Hoff, N.A. Kling, R.F. Lambiase, V. LoDestro, R. Lockey, M. Mapes, A. McNerney, J. Morris, M. Okamura, A. Pendzick, D. Phillips, A.I. Pikin, D. Raparia, J. Ritter, T.C. Shrey, L. Smart, L. Snydstrup, C. Theisen, M. Wilinski, A. Zaltsman, K. Zeno BNL, Upton, Long Island, New York, USA U. Ratzinger, A. Schempp IAP, Frankfurt am Main, Germany
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, and by the National Aeronautics and Space Administration. The construction and initial commissioning phase of a new heavy ion preinjector was completed at Brookhaven in September, 2010, and the preinjector is now operational. This preinjector, using an EBIS source to produce high charge state heavy ions, provided helium and neon ion beams for use at the NASA Space Radiation Laboratory in the Fall of 2010, and gold and uranium beams are being commissioned during the 2011 run cycle for use in RHIC. The EBIS operates with an electron beam current of up to 10 A, to produce mA level currents in 10 to 40 μs beam pulses. The source is followed by an RFQ and IH linac to accelerate ions with q/m > 0.16 to an energy of 2 MeV/amu, for injection into the Booster synchrotron. The performance of the preinjector is presented, including initial operational experience for the NASA and RHIC programs.

WEP267	Estimates of the Number of Foil Hits for Charge Exchange Injection	linac, proton, ion, betatron	1975
	D. Raparia 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. For high intensity circular proton machines, one of the major limitations is the charge exchange injection foil. The number of foil hits due to circulating beam may cause the foil to fail and cause radiation due to multiple nuclear scattering and energy straggling. This paper will describe methods to estimate these quantities without going through lengthy simulations.

WEP295	Status of Laser Stripping at the SNS	laser, optics, linac, quadrupole	2035
	T.V. Gorlov, A.V. Aleksandrov, V.V. Danilov ORNL, Oak Ridge, Tennessee, USA Y. Liu ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work was supported by SNS through UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 for the U.S. Department of Energy. This paper presents an overview of experimental and theoretical studies on laser stripping that have been conducted up to the present time in the SNS project. The goal of this work is to develop techniques to achieve the experimental preconditions necessary for the successful realization of a future intermediate experiment on laser stripping. The experimental work consists of the tuning and measurement of H־ beam parameters in readiness for the intermediate experiment, and also takes into account the features and possibilities of the SNS accelerator.

THOCN6	Flux-coupled Cyclotron Stack: Optimization for Maximum Beam Power and Minimum Losses	cavity, coupling, cyclotron, extraction	2113
	P.M. McIntyre, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: This work was supported in part by the U.S. Department of Energy under Grant DE-FG02-06ER41405 A flux-coupled stack of isochronous cyclotrons has been proposed as a driver for Accelerator-Driven Subcritical Systems (ADSS) for thorium-cycle fission power. The issues that limit beam current and phase space brightness are evaluated, including space charge tune shift, synchro-betatron coupling, orbit separation at injection and extraction, RF propagation within the accelerator envelope, RF parasitic modes, and stability of electrostatic septum operation. A design is presented that offers good optimization of these criteria.
	Slides THOCN6 [5.266 MB]

THP027	Status and Development of a Proton FFAG Accelerator at KURRI for ADSR Study	proton, linac, ion, ion-source	2172
	Y. Kuriyama, Y. Ishi, J.-B. Lagrange, Y. Mori, R. Nakano, T. Planche, T. Uesugi, E. Yamakawa KURRI, Osaka, Japan Y. Niwa, K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	In Kyoto University Research Reactor Institute (KURRI), the fixed-field alternating gradient (FFAG) proton accelerator has been constructed to make an experimental study of accelerator driven sub-critical reactor (ADSR) system with spallation neutrons produced by the accelerator. The world first ADSR experiment has been carried out in March of 2009. The proton FFAG accelerator consists of three FFAG rings; injetor (spiral sector FFAG), booster(radial sector FFAG) and main ring(radial sector FFAG), respectively. In March 2010, the experiment conducted with a thorium-loaded accelerator driven system using the proton FFAG accelerator has also been carried out. In order to increase the beam intensity of the proton FFAG accelerator, a new injector with H⁻ ions is under construction. In this scheme, H⁻ ions accelerated up to the energy of 11 MeV with a linac are injected into the main ring with charge-exchange injection. In this paper, the details of ADSR experiments with the proton FFAG accelerator at KURRI, and also the R&Ds of the accelerator will be presented.

THP056	Near Real-time ORM Measurements and SVD Matrix Generation for 10 Hz Global Orbit Feedback In RHIC	feedback, dipole, ion, damping	2226
	C. Liu, R.L. Hulsart, W.W. MacKay, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty 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. To reduce the effect of trajectory perturbations due to vibrations of the final focusing quadrupoles at RHIC, global orbit feedback was successfully prototyped during run-10. The system was tested using transfer functions between the beam position monitors and correctors obtained from the online optical model and a correction algorithm based on singular value decomposition (SVD). In run-11 we plan to self-calibrate the system using SVD matrices derived from orbit response matrix (ORM) measurements acquired real-time using the new FPGA-based signal processing. Comparisons between measurement and model and of feedback performance with the two methods are presented.

THP062	Beam Experiments Related to the Head-on Beam-beam Compensation Project at RHIC	electron, proton, cathode, lattice	2243
	C. Montag, M. Bai, K.A. Drees, W. Fischer, A. Marusic, G. Wang 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. Beam experiments have been performed in RHIC to determine some key parameters of the RHIC electron lenses, and to test the capability of verifying lattice modifications by beam measurements. We report the status and recent results of these experiments.

THP131	Injection Straight Pulsed Magnet Error Tolerance Study for Top-off Injection	kicker, septum, simulation, betatron	2366
	G.M. Wang, R.P. Fliller, R. Heese, S. Kowalski, B. Parker, T.V. Shaftan, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 NSLS II is designed to work in top-off injection mode. The goal is to minimize the disturbance of the injection transient on the users. The injection straight includes a septum and four fast kicker magnets. The pulsed magnet errors will excite a betatron oscillation. This paper gives the formulas of each error contribution to the oscillation amplitude at various source points in the ring. These are compared with simulation results. Based on the simple formulas, we can specify the error tolerances on the pulsed magnets and scale it to similar machines.

THP132	Beam Diagnostics using BPM Signals from Injected and Stored Beams in a Storage Ring	storage-ring, closed-orbit, simulation, betatron	2369
	G.M. Wang, W.X. Cheng, R.P. Fliller, R. Heese, T.V. Shaftan, O. Singh, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. For top-off injection mode, the storage ring always has the stored beam and injected beam. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use a BPM with special electronics in NSLS II storage ring to retrieve the injected beam trajectory with the SVD method. The BPM has the capability to measure bunch-by-bunch beam position. We also need another system to measure the bunch-by-bunch beam current. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.

THP134	Lifetime Measurement with Pseudo Moveable Septum in NSLS X-ray Ring	septum, closed-orbit, kicker, vacuum	2375
	G.M. Wang, J. Choi, R. Heese, S.L. Kramer, T.V. Shaftan, X. Yang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886 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 and starts to commission in 2014. The beam injection works with two septa and four fast kicker magnets in an injection section. To improve the injection stability and reproducibility, we plan to implement a slow local bump on top of the fast bump so that the fast kicker strength is reduced. This bump works as a pseudo movable septum. We can also use this ‘movable’ septum to measure the storage ring beam partial lifetime resulting from the septum edge and possibly increasing the lifetime by moving the stored beam orbit away from the edge. We demonstrate the feasibility of this idea, by implementing DC bump in NSLS X-ray ring. We report the results of beam lifetime measurements as a function of the amplitude of this bumped orbit relative to the septum and the idea of a slow bump that could reduce the fast bump magnet strengths.

THP135	Implementation of a DC Bump at the Storage Ring Injection Straight Section	septum, kicker, storage-ring, vacuum	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.

THP178	Design of the MAX IV Ring Injector and SPF/FEL Driver	linac, FEL, electron, simulation	2447
	S. Thorin, M. Eriksson, M.A.G. Johansson, D. Kumbaro, F. Lindau, L. Malmgren, J.H. Modéer, M. Sjöström, S. Werin MAX-lab, Lund, Sweden D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The MAX IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (in phase 2). Compression is done in two double achromats with positive R56. The natural second order momentum compaction, T566, from the achromats is used together with weak sextupoles to linearise longitudinal phase space, leaving no need for a linearising harmonic cavity. The design of the linac focuses on flexibility, simplicity and stability, while keeping the costs low. The accelerator structures have been ordered, as well as modulator/klystrons. The linac will be the first accelerator to be assembled and commissioned in the MAX IV project, starting mid 2012.

THP186	Lattice Design for ERL Options at SLAC	linac, emittance, lattice, extraction	2465
	Y. Nosochkov, Y. Cai, X. Huang, M.-H. Wang SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract number DE-AC02 76SF00515. SLAC is investigating long-range options for building a high performance light source machine while reusing the existing linac and PEP-II tunnels. One previously studied option is the PEP-X low emittance storage ring. The alternative option is based on a superconducting Energy Recovery Linac (ERL) and the PEP-X design. The ERL advantages are the low beam emittance, short bunch length and small energy spread leading to better qualities of the X-ray beams. Two ERL configurations differed by the location of the linac have been studied. Details of the lattice design and the results of beam transport simulations with the coherent synchrotron radiation effects are presented

THP189	Low Horizontal Beta Function in Long Straights of the NSLS-II Lattice	lattice, dynamic-aperture, sextupole, insertion	2471
	F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang BNL, Upton, 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	lattice, quadrupole, insertion, insertion-device	2474
	F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang BNL, Upton, 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.

THP191	Recent Progress in Injector Improvement of SPEAR 3	booster, quadrupole, linac, storage-ring	2477
	K. Tian, W.J. Corbett, D. Dell'Orco, D. Ernst, S.M. Gierman, J.A. Safranek, J.F. Schmerge, B. Scott SLAC, Menlo Park, California, USA
	The frequent injection and high current operation of SPEAR 3 storage ring requires high stability of the injector system at the Stanford Synchrotron Radiation Laboratory (SSRL). The lattice of linac-to-booster (LTB) transport line was not well understood and controlled prior to this work. In this paper, we discuss the significant efforts that have been made to improve the performance of the LTB. A method to correct the distortion of the closed orbit in the booster by moving 2 quadrupoles is also presented.

THP213	Traveling Wave Electron Linac for Synchrotron Injector	linac, electron, synchrotron, simulation	2519
	S.V. Kutsaev, K.I. Nikolskiy, N.P. Sobenin MEPhI, Moscow, Russia
	In this paper the project design of a travelling wave electron linac used as an injector to synchrotron in Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS) is presented. The injected beam to the synchrotron should have very small emittance and energy spectrum. Thus, the buncher design is an essential question in this problem. One of the best output beam parameters can be achieved by using a waveguide buncher with the non-uniform parameters. The proposals of optimal buncher design and beam dynamics calculation results are presented.

THP214	Pulsed Multipole Injection for the MAX IV Storage Rings	storage-ring, multipole, septum, sextupole	2522
	S.C. Leemann MAX-lab, Lund, Sweden
	The MAX IV facility presently under construction will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production for x-rays while the 1.5 GeV ring will serve UV and IR users. Both rings will be operated at a constant 500 mA of stored current with top-up shots supplied by the 3.5 GeV MAX IV linac acting as a full-energy injector. So far, injection into both storage rings has been designed using a conventional approach: a closed four-kicker injection bump brings the stored beam to the septum blade where the injected bunches are captured in a single turn. Recently, studies have been carried out to investigate the feasibility of using a pulsed multipole for injection into the storage rings. Pulsed multipole injection does not require an injection bump and has the potential to make top-up injection transparent to users. This paper reports on these studies and summarizes requirements for the pulsed sextupole magnet to be installed for injection into the MAX IV storage rings.

THP216	Progress with NSLS-II Injection Straight Section Design	septum, kicker, storage-ring, vacuum	2528
	T.V. Shaftan, A. Blednykh, W.R. Casey, L.R. Dalesio, R. Faussete, M.J. Ferreira, R.P. Fliller, G. Ganetis, R. Heese, H.-C. Hseuh, P.K. Job, E.D. Johnson, B.N. Kosciuk, S. Kowalski, S.L. Kramer, D. Padrazo, B. Parker, I. Pinayev, S.K. Sharma, O. Singh, C.J. Spataro, G.M. Wang, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by U.S. DOE, Contract No.DE-AC02-98CH10886 NSLS-II injection straight section consists of the pulsed and DC/Slow bumps, septa system, beam trajectory correction and diagnostics systems. In this paper we discuss overall injection straight layout, preliminary element designs, specifications for the pulsed and DC magnets and their power supplies, vacuum devices and chambers and diagnostics devices.

THP217	Frequent Fill Top-Off Injection at SPEAR3	controls, feedback, linac, power-supply	2531
	J.J. Sebek, S. Allison, S.M. Gierman, X. Huang, J.A. Safranek, J.F. Schmerge, K. Tian, C. Wermelskirchen SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76-SF00515 SPEAR3 beam is now delivered to users in a "frequent fill" mode in which beam is injected into the storage ring, with beam-line shutters open, on a periodic schedule so that the beam current is kept constant to within 1% of its average value. This goal was achieved with the constraints of having the SPEAR3 injector run at very high reliability and ensuring that there would be no challenges to the beam containment system in this operational mode. This paper presents the accelerator development, the hardware changes, and the software developed to implement this operational mode.

FROBN3	Project X - New Multi Megawatt Proton Source at Fermilab	linac, proton, cavity, collider	2566
	S. Nagaitsev Fermilab, Batavia, USA
	Fermilab plans to replace its present injection complex consisting of a pulsed linac and 15 Hz Booster with a new injection complex based on a superconducting CW linac. This new proton source should boost the power of the Main Injector to 2 MW and enable new experiments with a high power proton beam in the range of 1-3 GeV. The speaker will present recent developments from the Fermilab Project X R&D.
	Slides FROBN3 [2.018 MB]

Paper

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MOOBS2

Status of High Intensity Effects in the Spallation Neutron Source Accumulator Ring

space-charge, coupling, resonance, collective-effects

17

S.M. Cousineau
ORNL, Oak Ridge, Tennessee, USA

Funding: This research is supported by UT-Battelle, LLC for the U. S. Department of Energy under contract No. DE-AC05-00OR22725
The 248-meter Spallation Neutron Source (SNS) accumulator ring has accumulated up to 1.55·10¹⁴, 1 GeV protons. At this intensity, space charge effects contribute significantly to the beam dynamics. Here we present observations of space charge effects in the SNS ring, with emphasis on space charge effects and e-p instabilities.

Slides MOOBS2 [3.704 MB]

MOOCN1

Status of the LHC Operations and Physics Program

luminosity, proton, vacuum, status

32

S. Redaelli
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) has just completed a successful first year of operation. In 2010, the primary goal to achieved a peak luminosity of 10³²cm⁻²s⁻¹ at a 7 TeV centre-of-mass energy was achieved and the machine achieved safely and reliably routine operation in the multi-MJ regime. The good results of 2010 have laid a solid foundation towards the achievement of the primary physics goal to deliver an integrated luminosity of 1 fb⁻¹ in 2011. A fast and efficient LHC re-commissioning in 2011 lead already to a peak luminosity of 2.5×10³²cm⁻²s⁻¹ achieved in the fourth commissioning week. In this paper, the 2010 commissioning experience is reviewed and the present status and perspective are presented.

Slides MOOCN1 [15.792 MB]

MOODS4

Dancing Bunches as van Kampen Modes

impedance, synchrotron, damping, proton

94

A.V. Burov
Fermilab, Batavia, USA

Theory of van Kampen modes is applied to bunch longitudinal motion. Case of inductive impedance domination is studied in more details. Threshold for loss of Landau damping is found to be very sensitive to fine structure of the distribution function. Good agreement with the Tevatron's "dancing bunches" is obtained.

Slides MOODS4 [0.408 MB]

MOP021

The MICE Muon Beamline and Induced Host Accelerator Beam Loss

target, factory, synchrotron, emittance

148

A.J. Dobbs, A. Alekou, K.R. Long
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: Science and Technology Facilities Council
The international Muon Ionisation Cooling Experiment (MICE) is designed to provide a proof of principle of ionisation cooling to reduce the muon beam phase space at a future Neutrino Factory and Muon Collider. The MICE Muon Beam is generated by the decay of pions produced by dipping a cylindrical titanium target into the proton beam of the 800 MeV ISIS synchrotron at the Rutherford Appleton Laboratory, U.K. Studies of the particle rate in the MICE Muon Beamline and its relationship to induced beam loss in ISIS are presented, using data taken in Summer 2010. Using time-of-flight to perform particle identification estimates of muon rates are presented and related to induced beam loss.

MOP051

End-to-End Simulation of an Inverse Cyclotron for Muon Cooling

cyclotron, simulation, emittance, collider

193

K. Paul, E. Cormier-Michel
Tech-X, Boulder, Colorado, USA
T. Hart, D.J. Summers
UMiss, University, Mississippi, USA

Funding: DOE Office of High-Energy Physics, SBIR DE-FG02-08ER85044
Neutrino factories and muon colliders require significant cooling of the muon beam. Most muon cooling channels are long and expensive single-pass structures, due to the difficulty injecting very large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problems associated with other circular cooling channels, and they can potentially provide substantial initial cooling of the beam. We present the first end-to-end (injection to extraction) simulations of an inverse cyclotron for muon cooling, performed with the particle-in-cell code VORPAL. We study the cooling capability of the device as well as potential limitations due to space charge effects and material interactions with the beam.

MOP082

Modeling a 10 GeV Laser-Plasma Accelerator with INF&RNO

plasma, laser, simulation, electron

250

C. Benedetti, E. Esarey, W. Leemans, C.B. Schroeder
LBNL, Berkeley, California, USA

Funding: Work supported by the Office of Science, Office of High Energy Physics, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The numerical modeling code INF&RNO (INtegrated Fluid & paRticle simulatioN cOde, pronounced "inferno") is an efficient 2D cylindrical code to model the interaction of a short laser pulse with an underdense plasma. The code is based on an envelope model for the laser while either a particle-in-cell (PIC) or a fluid description can be used for the plasma. The effect of the laser pulse on the plasma is modeled with the time-averaged ponderomotive force. These and other features allow for a significant speedup compared to standard full PIC simulations while still retaining physical fidelity. A boosted Lorentz frame (BLF) modeling capability has been introduced within the fluid framework enhancing the performance of the code. An example of a 10 GeV laser-plasma accelerator modeled using INF&RNO in the BLF is presented.

MOP101

Numerical Study of Self and Controlled Injection in 3-Dimensional Laser-Driven Wakefields

plasma, simulation, laser, electron

286

A.W. Davidson, R. Fenseca, C. Joshi, W. Lu, J.L. Martins, W.B. Mori, L.O. Silva
UCLA, Los Angeles, California, USA

Funding: DOE and NSF
In plasma based accelerators (LWFA and PWFA), the methods of injecting high quality electron bunches into the accelerating wakefield is of utmost importance for various applications. Understanding how injection occurs in both self and controlled scenarios is therefore important. To simplify this understanding, we start from single particle motion in an arbitrary traveling wave wakefields, an electromagnetic structure with a fixed phase velocity(e.g., wakefields driven by non-evolving drivers), and obtain the general conditions for trapping to occur. We then compare this condition with high fidelity 3D PIC simulations through advanced particle and field tracking diagnostics. Numerous numerical convergence tests were performed to ensure the correctness of the simulations. The agreement between theory and simulations helps to clarify the role played by driver evolution on injection, and a physical picture of injection first proposed in * is confirmed through simulations. Several ideas, including ionization assisted injection, for achieving high quality controlled injection were also explored and some simulation results relevant to current and future experiments will be presented.
*W. Lu et al., PRSTAB 10, 061301, 2007

MOP123

Colliding Pulse Injection Control in a Laser-Plasma Accelerator

laser, plasma, collider, controls

325

C.G.R. Geddes, M. Chen, E. Esarey, W. Leemans, N.H. Matlis, D.E. Mittelberger, K. Nakamura, G.R.D. Plateau, C.B. Schroeder, C. Tóth
LBNL, Berkeley, California, USA
D.L. Bruhwiler, J.R. Cary, E. Cormier-Michel, B.M. Cowan
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by the U.S. Department of Energy, National Nuclear Security Administration, NA-22, and in part by the Office of Science under Contract No. DE-AC02-05CH11231.
Control of injection into a high gradient laser-plasma accelerator is presented using the beat between two ’colliding’ laser pulses to kick electrons into the plasma wake accelerating phase. Stable intersection and performance over hours of operation were obtained using active pointing control. Dependence of injector performance on laser and plasma parameters were characterized in coordination with simulations. By scanning the intersection point of the lasers, the injection position was controlled, mapping the acceleration length. Laser modifications to extend acceleration length are discussed towards production of tunable stable electron bunches as needed for applications including Thomson gamma sources and high energy colliders.

MOP159

Ionization-Induced Trapping in Laser-Plasma Accelerators and Synchrotron Radiation from the Betatron Oscillation

electron, laser, radiation, simulation

394

M. Chen, E. Esarey, C.G.R. Geddes, W. Leemans, C.B. Schroeder
LBNL, Berkeley, California, USA
D.L. Bruhwiler, E. Cormier-Michel
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by the U.S. DOE Office of High Energy Physics under Contract No. DE-AC02-05CH11231, and NNSA, NA-22, and used the computational resources of NERSC.
Ionization injection into a laser wakefield accelerator is studied by multi-dimensional particle-in-cell (PIC) simulations. To obtain low energy spread beams we use a short region of gas mixture (H⁺N) near the start of the stage to trap electrons, while the remainder of the stage uses pure H and is injection-free. Effects of gas mix parameters, including concentration and length of the mixture region, on the final electron injection number and beam quality are studied. Two dimensional PIC simulations show the injected electron beam has filament structures in the plane perpendicular to the laser polarization direction in early time and this structure disappears later due to the betatron oscillation of the electrons in the wakefield. Synchrotron radiation from the accelerated electrons is calculated by a post processing code - Virtual Detector for Synchrotron Radiation (VDSR).

MOP166

Comissioning of a BPM system for the LNLS Booster to Storage Ring Transfer Line

booster, controls, monitoring, storage-ring

405

F.H. Cardoso, S.R. Marques, X.R. Resende
LNLS, Campinas, Brazil

In order to increase the number of diagnostics and make possible studies of beam position effects in the injection efficiency, a beam position monitoring system was designed to equip the BTS (booster to storage ring) transfer line employing the long striplines BPMs. The log-ratio technique was applied using a commercial electronics module (LR-BPM) from Bergoz Instrumentation. Currently the system is integrated to the LNLS control system, database and ready to be used routinely during the injections. This work describes the system topology, details about the hardware and software, bench tests and measurements performed with electron beam. Future plans to improve the injection efficiency will also be presented.

MOP174

The Study and Implementation of Signal Processing Algorithm for Digital Beam Position Monitor

storage-ring, brilliance, betatron, extraction

414

L.W. Lai, Z.C. Chen, Y.B. Leng, Y.B. Yan, G.S. Yang
SSRF, Shanghai, People's Republic of China
X. Yi
SINAP, Shanghai, People's Republic of China

Digital beam position monitor (DBPM) system is one of the most important beam diagnostic instruments generally used in modern accelerators. The performance of DBPM is mainly given by its digital signal processing algorithm. In order to find out a better solution for our new DBPM system, two algorithms have been designed and implemented on a commercial FPGA based DAQ module (ICS1554) to retrieve the turn-by-turn (TBT) data. The first algorithm is based on frequency mixing, and the second one on discrete Fourier transform (DFT). Laboratory tests show that the standard deviation of measured positions can be better than 1μm at 5 dBm with input signal stronger than 5 dBm for both algorithms. And on-line evaluation indicates that real beam motion can be observed correctly using either algorithm.

MOP183

First Measurements of a New Beam Position Processor on Real Beam at Taiwan Light Source

brilliance, betatron, controls, storage-ring

429

P. Leban, A. Košiček
I-Tech, Solkan, Slovenia
P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo
NSRRC, Hsinchu, Taiwan

Libera Electron, Libera Brilliance and Libera Brilliance⁺ compose the electron beam position processors product family, which covers the needs of wide variety of the circular light source machines. The instruments deliver unprecedented possibilities for either building powerful single station solutions or architecting complex feedback systems. Compared to its predecessors (Libera Electron and Libera Briliance), the latest member of the family Libera Brilliance⁺ allows even more extensive machine physics studies to be conducted due to large data buffers and the new true turn-by-turn position calculation. It offers a large playground for custom- written applications with VirtexTM 5 and COM Express Basic module with Intel Atom N270 (x86) inside. First field tests of the new product were performed on real beam at Taiwan Light Source (TLS). The test setup, measurements and results are discussed in the paper.

MOP205

NSLS-II Injection Straight Diagnostics

vacuum, septum, kicker, diagnostics

477

I. Pinayev, A. Blednykh, M.J. Ferreira, R.P. Fliller, B.N. Kosciuk, T.V. Shaftan, G.M. Wang
BNL, Upton, Long Island, New York, USA

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 the paper we present the diagnostics installed on the injection straight. Its usage for commissioning and tuning of the injection cycle is also described.

MOP210

Residual Gas Fluorescence Monitor at RHIC

ion, emittance, vacuum, heavy-ion

492

T. Tsang, D.M. Gassner
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by U.S. Department of Energy under Contract No. DE-AC02-98CH10886.
A residual gas fluorescence beam profile monitor at the relativistic heavy ion collider (RHIC) has successfully recorded vertical beam sizes of Au-ion beams from 3.85 to 100 GeV/n during the 2010 beam runs. Although the fluorescence cross section of Au-ion is sufficiently large, the low residual gas in a typical vacuum chamber of <10-9 torr produces necessary weak fluorescence photons. However, with adequate CCD exposure time, the vertical beam profiles are captured to provide an independent measurement of the RHIC beam size and emittance. This beam diagnostic technique, utilizing the Au-ion beam induced fluorescence from residual gas where hydrogen is still the dominant constituent in nearly all vacuum system, represents a step towards the realization of a truly noninvasive beam monitor for high-energy particle beams.

MOP211

NSLS-II RF Beam Position Monitor

controls, feedback, EPICS, storage-ring

495

K. Vetter, J.H. DeLong, A.J. Della Penna, K.M. Ha, Y. Hu, B.N. Kosciuk, J. Mead, I. Pinayev, O. Singh, Y. Tian
BNL, Upton, Long Island, New York, USA
G.J. Portmann
LBNL, Berkeley, California, USA
J.J. Sebek
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. DOE under contract No. DE-AC02-98CH10886.
An internal R&D program has been undertaken at BNL to develop a sub-micron RF Beam Position Monitor (BPM) for the NSLS-II 3rd generation light source that is currently under construction. The BPM R&D program started in August 2009. Successful beam tests were conducted 15 months from the start of the program. The NSLS-II RF BPM has been designed to meet all requirements for the NSLS-II Injection system and Storage Ring. Housing of the RF BPMs in ±0.1C thermally controlled racks provide sub-micron stabilization without active correction. An active pilot-tone has been incorporated to aid long-term (8hr min) stabilization to 200nm RMS.

MOP222

Operational Use of Ionization Profile Monitors in the Fermilab Main Injector

antiproton, proton, controls, vacuum

519

D.K. Morris, P. Adamson, D. Capista, I. Kourbanis, T. Meyer, K. Seiya, D. Slimmer, M.-J. Yang, J.R. Zagel
Fermilab, Batavia, USA

Funding: Operated by the Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Ionization profile monitors (IPMs) are used in the Fermilab Main Injector (MI) for injection lattice matching and to measure transverse emittance of the beam during acceleration. The IPMs provide a periodic, non-destructive means for emittance measurements where other techniques are not applicable. As Fermilab is refocusing its attention on the intensity frontier, non-intercepting diagnostics such as IPMs are expected to become even more important. This paper gives an overview of the operational use of IPMs for emittance measurements and injection lattice matching measurements at Fermilab, and summarizes the future plans.

MOP263

Fast Orbit Feedback System for the LNLS Storage Ring

feedback, controls, storage-ring, synchrotron

597

L. Sanfelici, F.H. Cardoso, D.D. Felix Ferreira, S.R. Marques, D.O. Tavares
LNLS, Campinas, Brazil

The Brazilian Synchrotron Light Laboratory (LNLS) is based on a 1.37 GeV storage ring, previously operated by means of a Slow Orbit Feedback System at a maximum rate of 1 correction every 3 seconds. Since photon flux stability is a key issue for light source users, a faster control system was envisaged to provide better beam stability. This work presents an overview of the hardware architecture and the preliminary results achieved with the implementation of a Fast Orbit Feedback System using commercial hardware. BPM signals are acquired in a distributed topology and sent through a deterministic EtherCAT network to a PXI controller, responsible for applying the SVD-based correction matrix multiplication and communicating with the accelerator control system; the calculated current setpoints are sent to the correctors’ power supplies through a second EtherCAT network. FPGA-based acquisition and actuation chassis perform pre-filtering and control on the digitized input and output signals, respectively.

MOP272

Radiation Dose Level in the SSRF during Normal Operation

radiation, monitoring, neutron, storage-ring

615

X.J. Xu, P. Fei, R. Qin, W. Shen, X. Xia, D. Zhang, J.Z. Zhou
SINAP, Shanghai, People's Republic of China

Shanghai Synchrotron Radiation Facility (SSRF) has been commissioned since December 2007, and has been formally operated since May 2009. In order to ensure the radiation safety for staff members and publics, the radiation levels of the workplace, the environment and the staff are monitored through a real-time network of gamma and neutron monitors as well as through TLD passive dosimeters. This paper reports the results of the radiation monitoring. From these results, we found that the annual dose equivalents were good to meet the management values of SSRF.

MOP274

Beam Loss Monitors for NSLS-II Storage Ring

electron, shielding, radiation, dipole

621

S.L. Kramer, P. Cameron
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding for the NSLS-II storage ring will provide adequate protection for the full injected beam losses in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of <10% top-off injection beam current. This will require a system to insure that beam losses do not exceed these levels for a period of time that could cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring system will have beam loss monitors that will measure where the beam charge is lost around the ring, to warn operators if losses approach the design limits. In order to measure the charge loss quantitatively, we propose measuring the electron component of the shower as beam electrons hit the vacuum chamber wall. This will be done using the Cerenkov light as charged particles transit an ultra-pure fused silica rod placed close to the inner edge of the VC. The length of rod will collect the light from many charged particles of the spread out shower resulting from the small glancing angle of the lost beam particles to the VC wall. The design and measurements results of the prototype Cerenkov BLM will be presented.

MOP275

Beam Loss Control for the NSLS-II Storage Ring

controls, dipole, beam-losses, shielding

624

S.L. Kramer, J. Choi
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The shielding design for the NSLS-II storage ring is designed for the full injected beam losses in two periods of the ring around the injection point, but for the remainder of the ring its shielded for <10% top-off injection beam. This will require a system to insure that beam losses do not exceed these levels for time sufficient to cause excessive radiation exposure outside the shield walls. This beam Loss Control and Monitoring (LCM) system will control the beam losses to the more heavily shielded injection region while monitoring the losses outside this region. To achieve this scrapers are installed in the injection region to intercept beam particles that might be lost outside this region. The scrapers will be thin (< 1Xrad) that will allow low energy electrons to penetrate and the subsequent dipole will separate them from the stored beam. These thin scrapers will reduce the radiation from the scraper compared to thicker scrapers. The dipole will provide significant local shielding for particles that hit inside the gap and a source for the loss monitor system that will measure the amount of beam lost in the injection region.
* Beam Loss Monitors for NSLS-II Storage Ring, S.L. Kramer & P. Cameron, these proceedings

MOP276

Applying Cascaded Parameter Scan to Study Top-off Safety in NSLS-II Storage Ring

simulation, photon, interlocks, storage-ring

627

Y. Li, S.V. Badea, W.R. Casey, G. Ganetis, R. Heese, H.-C. Hseuh, P.K. Job, S. Krinsky, B. Parker, T.V. Shaftan, S.K. Sharma, L. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
In this paper we introduce a new algorithm, the cascaded parameter scan method, to efficiently carry out the scan over magnet parameters in the safety analysis for the NSLS-II top-off injection. In top-off safety analysis, one must track particles populating phase space through a beamline containing magnets and apertures and clearly demonstrate that for all possible magnet settings and errors, all particles are lost on scrapers within the properly shielded region. In the usual approach, the number of tracking runs increases exponentially with the number of magnet settings. In the cascaded parameter scan method, the number of tracking runs only increases linearly. This reduction of exponential to linear dependence on the number of setpoints, greatly reduces the required computation time and allows one to more densely populate phase space and to increase the number of setpoints scanned for each magnet. An example of applying this approach to analyze an NSLS-II beamline, the damping wiggler beamline, is also given.

MOP284

A High Performance DAC / DDS Daughter Module for the RHIC LLRF Platform

LLRF, controls, luminosity, synchrotron

648

T. Hayes, M. Harvey, G. Narayan, F. Severino, K.S. Smith, S. Yuan
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 RHIC LLRF upgrade is a flexible, modular system. Output signals are generated by a custom designed XMC card with 4 high speed digital to analog converters interfaced to a high performance field programmable gate array (FPGA). This paper discusses the hardware details of the XMC DAC board as well as the implementation of a low noise rf synthesizer with digital IQ modulation. This synthesizer also provides injection phase cogging and frequency hop rebucketing capabilities.

MOP297

A Bunch to Bucket Phase Detector for the RHIC LLRF Upgrade Platform

LLRF, feedback, controls, synchrotron

675

K.S. Smith, M. Harvey, T. Hayes, G. Narayan, S. Polizzo, F. Severino
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
As part of the overall development effort for the RHIC LLRF Upgrade Platform, a 4 channel ADC daughter module was developed to provide high speed, wide dynamic range digitizing and processing of signals from DC to several hundred megahertz. The first operational use of this card was to implement the bunch to bucket phase detector for the RHIC LLRF beam control feedback loops. This paper will describe the design and performance features of this daughter module as a bunch to bucket phase detector, and also provide an overview of its place within the overall LLRF platform architecture as a high performance digitizer and signal processing module suitable to a variety of applications.

TUOBN1

Laser Wakefield Acceleration Beyond 1 GeV using Ionization Induced Injection

laser, electron, plasma, simulation

707

K.A. Marsh, C.E. Clayton, C. Joshi, N. Lemos, W. Lu, W.B. Mori, A.E. Pak
UCLA, Los Angeles, California, USA
F. Albert, T. Doeppner, C. Filip, D.H. Froula, S.H. Glenzer, B.B. Pollock, D. Price, J.E. Ralph
LLNL, Livermore, California, USA
R.A. Fonseca, S.F. Martins
Instituto Superior Tecnico, Lisbon, Portugal
L.O. Silva
IPFN, Lisbon, Portugal

Funding: Supported by DOE Grants No. DE-AC52-07NA27344, DE-FG03-92ER40727, DE-FG02-92ER40727, DE-FC02-07ER41500, DE-FG52-09NA29552, NSF Grants No. PHY-0936266, PHY-0904039 and FCT, Por., No. SFRH/BD/35749/2007
A series of laser wakefield accelerator experiments leading to electron energy exceeding 1 GeV are described. Theoretical concepts and experimental methods developed while conducting experiments using the 10 TW Ti:Sapphire laser at UCLA were implemented and transferred successfully to the 100 TW Calisto Laser System at the Jupiter Laser Facility at LLNL. To reach electron energies greater than 1 GeV with current laser systems, it is necessary to inject and trap electrons into the wake and to guide the laser for more than 1 cm of plasma. Using the 10 TW laser, the physics of self-guiding and the limitations in regards to pump depletion over cm-scale plasmas were demonstrated. Furthermore, a novel injection mechanism was explored which allows injection by ionization at conditions necessary for generating electron energies greater than a GeV. The 10 TW results were followed by self-guiding at the 100 TW scale over cm plasma lengths. The energy of the self-injected electrons, at 3x10¹⁸ cm^-3 plasma density, was limited by dephasing to 720 MeV. Implementation of ionization injection allowed extending the acceleration well beyond a centimeter and 1.4 GeV electrons were measured.

Slides TUOBN1 [2.488 MB]

TUOBS3

Status of the NSLS-II Project

vacuum, storage-ring, radiation, photon

732

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

NSLS-II, the new 3 GeV 3rd generation light source presently under construction at Brookhaven National Laboratory will provide ultra-bright synchrotron radiation of 10²¹ photons s^-1 mm^-2 mrad^-2 0.1% BW^-1 at 2keV and high photon flux of 10¹⁵ photons s^-1 0.1% BW^-1. The facility will support a minimum of 60 beamlines. Construction started in 2009 and commissioning is expected to be completed in 2014. This report will provide a description of the NSLS-II design and will summarize the status of the construction project.

Slides TUOBS3 [7.560 MB]

TUP190

Upgrade of the APS Booster Synchrotron Magnet Ramp

booster, dipole, controls, synchrotron

1181

C. Yao, B. Deriy, G. Feng, H. Shang, J. Wang
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06-CH11357
The APS booster is a 7-GeV electron synchrotron with 0.5-second cycle time. Both voltage and current ramp modes were in the original design but only the voltage ramp has been commissioned. Two software-based ramp control programs are used to regulate the current waveform to a linear ramp. The system has been operated for user beam operations for many years. Some instability exists in the ramp correction that requires manual intervention from time to time by the operators. Sensitivity of magnet currents to external changes, such as AC line voltage, harmonic interference from the high-power rf system, etc., has been observed. In order to meet the increased single-bunch-charge requirement of the APS upgrade we need more flexible current ramps such as flat porches for injection and extraction and smooth transitions. Recent efforts to develop an energy-saving operation mode also call for ramp improvement. This paper presents test results of a workstation-based current regulation program and an FPGA-based implementation as a future upgrade.

TUP195

Commissioning the ALS Digital Power Supply Controller in the Booster Dipole and Quadrupole Magnet Power Supplies

booster, controls, power-supply, quadrupole

1190

J.M. Weber, T. Scarvie, C. Steier, CA. Timossi
LBNL, Berkeley, California, USA

Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. A few years ago, the ALS was upgraded to achieve Top-Off Mode, which required replacing the booster dipole and quadrupole magnet power supplies to increase the peak booster beam energy from 1.5GeV to 1.9GeV. The original analog controller for each power supply has been replaced by a digital power supply controller (DPSC) to improve stability and resolution and provide a remote interface. The DPSC capabilities include 24-bit 100k-point digital reference waveform download and voltage reference generation, and complete digital current loop implementation. The hardware includes an FPGA with an embedded processor running a full EPICS IOC on VxWorks. This paper will present the current functionality of the DPSC as well as performance results from recent commissioning.

TUP202

Non-Scaling FFAG Proton Driver for Project X

proton, linac, focusing, synchrotron

1199

C. Johnstone, D.V. Neuffer
Fermilab, Batavia, USA
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
L.J. Jenner, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
P. Snopok
IIT, Chicago, Illinois, USA

The next generation of high-energy physics experiments requires high intensity protons at multi-GeV energies. Fermilab’s HEP program, for example, requires an 8-GeV proton source to feed the Main Injector to create a 2 MW neutrino beams in the near term and would require a 4 MW pulsed proton beam for a potential Neutrino Factory or Muon Collider in the future. High intensity GeV proton drivers are difficult at best with conventional re-circulating accelerators, encountering duty cycle and space-charge limits in the synchrotron and machine size and stability concerns in the weaker-focusing cyclotrons. Only an SRF linac, which has the highest associated cost and footprint, has been considered. Recent innovations in FFAG design, however, have promoted another re-circulating candidate, the Fixed-field Alternating Gradient accelerator (FFAG), as an attractive, but as yet unexplored, alternative. Its strong focusing optics coupled to large transverse and longitudinal acceptances would serve to alleviate space charge effects and achieve higher bunch charges than possible in a synchrotron and presents an upgradeable option from the 2 MW to the 4 MW program.

TUP211

Compensation of Fast Kicker Rolls with Skew Quadrupoles

kicker, quadrupole, photon, coupling

1208

I. Pinayev
BNL, Upton, Long Island, New York, USA

The development of the third generation light sources lead to the implementation of the top-up operation, when injection occurs while users collect data. The beam excursions due to the non-closure of the injection bump can spoil the data and need to be suppressed. In the horizontal plane compensation can be achieved by adjusting timing and kick amplitudes. The rolls of the kicker magnets create non-closure in the vertical plane and usually there is no means for correction. In the paper we describe proposed compensation scheme utilizing two skew quadrupoles placed inside the injection bump.

TUP213

Research and Development toward the RHIC Injection Kicker Upgrade

kicker, high-voltage, factory, impedance

1211

W. Zhang, W. Fischer, H. Hahn, C. Pai, J. Sandberg, J.E. Tuozzolo
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.
A research and development work is on going toward the upgrade of the RHIC Injection Fast Kicker System. We report here the proposed nano-second pulse generator, the initial test result, the options of the deflector design, injection pattern, and the benefit to the future RHIC programs.

TUP221

Helium Pressures in RHIC Vacuum Cryostats and Relief Valve Requirements from Magnet Cooling Line Failure

vacuum, simulation, dipole, quadrupole

1229

C.J. Liaw, R. Than, J.E. Tuozzolo
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.
A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results.

TUP222

Helium Release Rates and ODH Calculations from RHIC Magnet Line Cooling Line Failure

vacuum, simulation, controls, collider

1232

C.J. Liaw, R. Than, J.E. Tuozzolo
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.
A catastrophic failure of the magnet cooling lines, similar to the LHC superconducting bus failure incident, could discharge cold helium into the RHIC tunnel and cause an Oxygen Deficiency Hazard (ODH) problem. A SINDA/FLUINT® model, which simulated the 4.5K/ 4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the insulating vacuum volumes and discharging via the reliefs into the RHIC tunnel, had been developed. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces are included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Results, including helium discharge rates, helium inventory loss, and the resulting oxygen concentration in the RHIC tunnel area, are reported. Good agreement had been achieved when comparing the simulation results, a RHIC sector depressurization test measurement, and some simple analytical calculations.

TUP232

Super-Conducting Wigglers and the Effect on Injection Efficiency

wiggler, simulation, storage-ring, betatron

1259

M.J. Sigrist, L.O. Dallin, W.A. Wurtz
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source has two superconducting wigglers (SCW) operating at 2.1T and 4.3T peak fields. Injection efficiency into the storage ring is reduced by either device operating at high fields. Currently the CLS operates with a Fill and Decay mode, injecting with both wigglers at reduced field to avoid low injection efficiencies. Future implementation of a Top-up mode will require both wigglers to be operating at full field and better injection efficiencies will be required. Simulations and experiments have shown that the poor injection efficiency is related to operating a high vertical chromaticity. Much improved efficiencies are observed at when the chromaticity is lowered. As well, small improvements to the injection efficiency have been achieved through local correction of the beta-beats and tune shifts caused by the wigglers and optimisation of the injection co-ordinates of the injected beam. Measurements of the injection efficiencies at various chromaticities will be presented along with the betatron oscillations before and after correction.

TUP254

Real Time Monitoring of the Power Limit Resistor in the Boost Injection Kicker Power Supply

power-supply, booster, kicker, status

1301

J.-L. Mi, J. Sandberg, Y. Tan, W. Zhang
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.
After years of suffering Booster Injection Kicker transistor bank driver regulator trouble shooting, a new real time monitor system has been developed. A simple and floating circuit has been designed and tested. This circuit monitor system can real time monitor the driver regulator power limit resistor status and warn machine operators if the power limit resistor changes values. This paper will introduce the power supply mainly and the new designed monitoring system.

TUP274

Oak Ridge National Laboratory Spallation Neutron Source Electrical Systems Availability and Improvements

kicker, extraction, pulsed-power, site

1337

R.I. Cutler, D.E. Anderson, W.E. Barnett, J.D. Hicks, J.J. Mize, J. Moss, K. Norris, V.V. Peplov, K.R. Rust, J. T. Weaver
ORNL, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
SNS electrical systems have been operational for 4 years. System availability statistics and improvements are presented for ac electrical systems, dc and pulsed power supplies and klystron modulators

TUP282

The MICE Target

target, acceleration, extraction, proton

1355

P.J. Smith, C.N. Booth, P. Hodgson, E. Overton, M. Robinson
Sheffield University, Sheffield, United Kingdom
G.J. Barber, K.R. Long
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
E.G. Capocci, J.S. Tarrant
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
B.J.A. Shepherd
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The MICE experiment uses a beam of low energy muons to test the feasibility of ionization cooling. This beam is derived parasitically from the ISIS accelerator at the Rutherford Appleton Laboratory. A target mechanism has been developed and deployed that rapidly inserts a small titanium target into the circulating proton beam immediately prior to extraction without undue disturbance of the primary ISIS beam. The first target drive was installed in ISIS during 2008 and operated successfully for over 100,000 pulses. A second upgraded design was installed in 2009 and after more than half a million actuations is still in operation. Further upgrades to the target design are now being tried in a separate test rig at the Rutherford Appleton Laboratory. The technical specifications for these upgraded designs are given and the motivations for the improvements are discussed. Additionally, further future improvements to the current design are discussed.

WEOBN1

Simultaneous Orbit, Tune, Coupling, and Chromaticity Feedback at RHIC

feedback, coupling, betatron, controls

1394

M.G. Minty, A.J. Curcio, W.C. Dawson, C. Degen, R.L. Hulsart, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, P. Oddo, V. Ptitsyn, G. Robert-Demolaize, T. Russo, V. Schoefer, C. Schultheiss, S. Tepikian, M. Wilinski
BNL, Upton, Long Island, New York, USA
T. Satogata
JLAB, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
All physics stores at the Relativistic Heavy Ion Collider are now established using simultaneous orbit, tune, coupling, and energy feedback during beam injection, acceleration to full beam energies, during the “beta-squeeze” for establishing small beam sizes at the interaction points, and during removal of separation bumps to establish collisions. In this report we describe the major changes made to enable these achievements. The proof-of-principle for additional chromaticity feedback will also be presented.

Slides WEOBN1 [8.054 MB]

WEOBN6

LARP LHC 4.8 GHz Schottky System Initial Commissioning with Beam

pick-up, proton, controls, ion

1413

R.J. Pasquinelli
Fermilab, Batavia, USA
F. Caspers, O.R. Jones
CERN, Geneva, Switzerland
A. Jansson
ESS, Lund, Sweden

The LHC Schottky system consists for four independent 4.8 GHz triple down conversion receivers with associated data acquisition systems. Each system is capable of measuring tune, chromaticity, momentum spread in either horizontal or vertical planes; two systems per beam. The hardware commissioning has taken place during the spring and summer of 2010. With nominal bunch beam currents of 10¹¹ protons, the first incoherent Schottky signals were detected and analyzed. This paper will report on these initial commissioning results. A companion paper will report on the data analysis curve fitting and remote control user interface of the system.

Slides WEOBN6 [27.117 MB]

WEOBS3

The Effects of a Density Mismatch in a Two-State LWFA

electron, cavity, laser, ion

1421

B.B. Pollock, F. Albert, C. Filip, D.H. Froula, S.H. Glenzer, J.E. Ralph
LLNL, Livermore, California, USA
C.E. Clayton, C. Joshi, K.A. Marsh, J. Meinecke, A.E. Pak, J.L. Shaw
UCLA, Los Angeles, California, USA
K.L. Herpoldt
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
G.R. Tynan
UCSD, La Jolla, California, USA

Funding: Work performed under U.S. DOE Contract DE-AC52-07NA27344 and was partially funded by the Laboratory Directed Research and Development Program under project tracking code 06-ERD-056.
A two-stage Laser Wakefield Accelerator (LWFA) has been developed, which utilizes the ionization induced injection mechanism to produce high energy, narrow energy spread electron beams when the electron density is equal in both stages. However, when the densities are not equal these high quality beams are not observed. As the electron density varies across the interface between the adjacent stages the size of the ion cavity is expected to change; this results in either a reduction of the peak electron energy (for a density decrease), or in the exclusion of previously trapped charge from the first wake period (for a density increase). The latter case can be overcome if the interaction length before the density interface exceeds a threshold determined by the densities in each stage, and may provide a mechanism for enhanced energy gain.

WEOCS2

Development of Nb3Sn 11 T Single Aperture Demonstrator Dipole for LHC Upgrades

dipole, collimation, magnet-design, multipole

1460

A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, V. Kashikhin, A. Nobrega, I. Novitski
Fermilab, Batavia, USA
B. Auchmann, M. Karppinen, L. Rossi
CERN, Geneva, Switzerland

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb3Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.

Slides WEOCS2 [2.523 MB]

WEP015

Initial Simulations of Electron and Ion Beam Optics for the ANL EBIS Electron Collector

electron, ion, simulation, cathode

1525

C. Dickerson, S.A. Kondrashev, P.N. Ostroumov
ANL, Argonne, USA
A.I. Pikin
BNL, Upton, Long Island, New York, USA

Funding: U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357
An Electron Beam Ion Source (EBIS) being developed at the Argonne National Laboratory (ANL) will be used to charge breed rare isotopes from a 1 Ci 252Cf source, the Californium Rare Isotope Breeder Upgrade (CARIBU). Simulations have been performed using commercially available software, TriComp, to ensure the electron collector is properly designed to dissipate the electron beam power and provide adequate acceptance for the injected ion beam.

WEP039

Tracking Stripped Proton Particles in SNS Ring Injection Momentum Dump Line

dipole, proton, simulation, collimation

1567

J. G. Wang
ORNL, Oak Ridge, Tennessee, USA

3D computer simulations are performed to study magnetic field distributions and particle trajectories along the SNS ring injection momentum dump line. Optical properties and transfer maps along the dump line are calculated. The stripped proton particle distributions on the dump window are analyzed. The study has provided useful information for the redesign of the SNS ring injection beam dump.

WEP062

Optimized Sextupole Configurations for Sextupole Magnet Failure in Top-up Operation at the APS*

sextupole, lattice, power-supply, dynamic-aperture

1588

V. Sajaev
ANL, Argonne, USA

Funding: Work supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Recently there was a situation at the APS when one sextupole power supply failed during top-up operation (all magnets at the APS have separate power supplies). The beam was not lost but the lifetime decreased significantly to the point where it was hard for the injectors to provide enough charge for top-up injections. Luckily, the power supply was able to reset quickly, and the operation was not compromised. One can anticipate similar failures in the future when it would not be possible to reset the power supply. In such a case, the APS would need to operate with lower lifetime until the next intervention period. Here we present an optimization of the sextupole distribution in the vicinity of the failed sextupole that allows us to partially recover the lifetime. A genetic optimization algorithm that involves simultaneous optimization of the dynamic and energy apertures was used*. Experimental tests are also presented.
* M. Borland et al., "Application of Direct Methods of Optimizing Storage Ring Dynamic and Momentum Apertures," Proc. ICAP2009, to be published.

WEP094

Space Charge Measurements with a High Intensity Bunch at the Fermilab Main Injector

proton, simulation, emittance, space-charge

1648

K. Seiya, B. Chase, J.E. Dey, P.W. Joireman, I. Kourbanis
Fermilab, Batavia, USA
A. Yagodnitsyna
NSU, Novosibirsk, Russia

Fermilab Main Injector will be required to operate with 3 times higher bunch intensity than today for Project X. The plan to study the space charge effects at the injection energy with intense bunches will be discussed.

WEP104

Transverse Feedback System and Instability Analysis at HLS

feedback, octupole, damping, resonance

1674

J.H. Wang, Y.B. Chen, W. Li, L. Liu, M. Meng, B.G. Sun, L. Wang, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In this paper, we introduce the BxB transverse feedback systems at Hefei Light Source (HLS), which employ an analog system and a digital system. The experiment result of two systems. as well as the primary analysis of beam instability in HLS injection and operation are also presented in this paper.

WEP125

Higher-order Spin Resonances in 2.1 GeV/c Polarized Proton Beam

resonance, polarization, proton, betatron

1716

M.A. Leonova, J. Askari, K.N. Gordon, A.D. Krisch, J. Liu, D.A. Nees, R.S. Raymond, D.W. Sivers, V.K. Wong
University of Michigan, Spin Physics Center, Ann Arbor, MI, USA
F. Hinterberger
Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany
V.S. Morozov
JLAB, Newport News, Virginia, USA

Funding: This research was supported by grants from the German Science Ministry
Spin resonances can cause partial or full depolarization or spin-flip of a polarized beam. We studied 1st-, 2nd- and 3rd-order spin resonances with a 2.1 GeV/c vertically polarized proton beam stored in the COSY Cooler Synchrotron. We observed almost full spin-flip when crossing the 1st-order G*gamma=8−nu_y vertical-betatron-tune spin resonance and partial depolarization near some 2nd- and 3rd-order resonances. We observed almost full depolarization near the 1st-order G*gamma=8−nu_x horizontal spin resonance and partial depolarization near some 2nd- and 3rd-order resonances. Moreover, we found that a 2nd-order nu_x resonance seems about as strong as some 3rd-order nu_x resonances, while some 3rd-order nu_y resonances seem much stronger than a 2nd-order nu_y resonance. It was thought that, for flat accelerators, vertical spin resonances are stronger than horizontal, and lower order resonances are stronger than higher order ones. The data suggest that many higher-order spin resonances, both horizontal and vertical, must be overcome to accelerate polarized protons to high energies; the data may help RHIC to better overcome its snake resonances between 100 and 250 GeV/c.

WEP133

Adaptive Space-charge Meshing in the General Particle Tracer Code

space-charge, electron, simulation, brightness

1728

S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands
O.J. Luiten, M.J. de Loos
TUE, Eindhoven, The Netherlands
G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Efficient and accurate space-charge calculations are essential for the design of high-brightness charged particle sources. Space-charge calculations in the General Particle Tracer (GPT) code make use of an efficient multigrid Poisson solver developed for non-equidistant meshes at Rostock University. GPT uses aggressive mesh-adaptation with highly non-equidistant spacing to speed up calcula- tion time, where the mesh line positions are based upon the projected charge density. Here we present a new meshing scheme where the solution of an intermediate step in the multigrid algorithm is used to define optimal mesh line positions. An analytical test case and comparison with a molecular dynamics calculation of an ultrafast electron diffraction experiment demonstrate the capabilities of this new algorithm in the GPT code.

WEP136

Modelling of the EMMA ns-FFAG Ring Using GPT

space-charge, quadrupole, emittance, electron

1734

R.T.P. D'Arcy
UCL, London, United Kingdom
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in Aug 2010. The energy recovery linac ALICE will serve as an injector for EMMA, within an energy range of 10^-20 MeV. The injection line consists of a dogleg to extract the beam from ALICE, a matching section, and tomography section for transverse emittance measurements. This is followed by a transport section to the injection point of the EMMA ring. The ring is composed of forty two cells, each containing one focusing and one defocusing quadrupole. Commissioning of the EMMA ring started in late 2010. A number of different injection energy and bunch charge regimes are planned; for some of the regimes the effects of space charge may be significant. It is therefore necessary to model the electron beam transport in the injection line and the ring using a code capable of both calculating the effect of and compensating for space charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modelled for comparison with experimental results.

WEP149

Beam Measurement by a Wall Gap Monitor in ALPHA

linac, dipole, electron, extraction

1761

T.H. Luo, P.D. McChesney, P.E. Sokol
IUCF, Bloomington, Indiana, USA
S.-Y. Lee
IUCEEM, Bloomington, Indiana, USA

In this report, we present our electron beam measurements with a wall gap monitor (WGM) in ALPHA injection and extraction beam lines. The WGM is first bench mark tested, and then installed in the ALPHA injection line to measure both the macro andμpulse of the injected beam and calibrate the beam current. By scanning the bending magnet before the WGM, and applying a demodulation signal processing scheme, we measured the tomography of the longitudinal phase space of the injected beam. We moved the WGM to extraction beam line and measured the properties of the extracted beam. By comparing the frequency spectrum of injected and extracted beam, we have confirmed the debunching performance of ALPHA.

WEP189

Compression and Synchronization of an Ultra-short Electron Beam Using a THz Undulator Interaction

undulator, laser, electron, radiation

1843

J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To
UCLA, Los Angeles, California, USA

Funding: DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272
Injection of electron beams into laser driven picosecond scale accelerating structures demand highly synchronized electron beams with bunch lengths approaching the femtosecond scale. One-dimensional numerical studies of undulator interactions of 3.5 MeV sub-picosecond electron beams and THz pulse trains produced by optical rectification have shown substantial compression and a reduction in time of arrival jitter with respect to the accelerator drive laser from the scale of hundreds of fs to that of tens of fs. In this paper a THz undulator based compression and synchronization scheme is investigated.

WEP199

Estimation of Ecloud and TMCI Driven Vertical Instability Dynamics from SPS MD Measurements - Implications for Feedback Control

feedback, controls, simulation, synchrotron

1861

O. Turgut, A. Bullitt, J.D. Fox, G. Ndabashimiye, C.H. Rivetta, M. Swiatlowski
SLAC, Menlo Park, California, USA
W. Höfle, B. Salvant
CERN, Geneva, Switzerland
R. Secondo
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under contract # DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
We present analysis of beam motion data obtained in high intensity SPS MD studies in 2009 and 2010. The single-bunch vertical E-cloud motion seen in parts of the bunch train after injection shows large tune shifts (roughly 0.02 above the 0.185 tune) developing between tail and head of unstable bunches. The unstable vertical motion has spectral content up to roughly 1.2 GHz and a quasi-periodic growth and decoherence relaxation oscillation effect is seen with time scales of hundred turns. Beam slice FFT and RMS techniques are illustrated to extract parameters important for the design of wide-band vertical feedback system, such as a growth rates of unstable motion, tune shifts within a single bunch and characterization of the bandwidth of the unstable structures within a bunch. We highlight the impact of synchrotron motion and injection transients on a proposed vertical processing channel. We present our MD plans including the beam driving process, developments in reduced model / identification techniques to extract dynamics from experimental and simulation data.
*J. Fox et al., ‘‘SPS Ecloud Instabilities - Analysis Of Machine Studies And Implications For Ecloud Feedback,'' IPAC'10, WEPEB052

WEP201

Status of NSLS-II Booster

booster, extraction, dipole, septum

1864

S.M. Gurov, A. Akimov, O. Anchugov, A.M. Batrakov, E.A. Bekhtenev, O.V. Belikov, P.B. Cheblakov, V.P. Cherepanov, A.D. Chernyakin, V.G. Cheskidov, I.N. Churkin, A.N. Dubrovin, A. Erokhin, K. Gorchakov, S.E. Karnaev, G.V. Karpov, V.A. Kiselev, V.V. Kobets, V.V. Kolmogorov, V.M. Konstantinov, A.A. Korepanov, E.A. Kuper, V. Kuzminykh, E.B. Levichev, V.R. Mamkin, A.S. Medvedko, O.I. Meshkov, N. Nefedov, V.V. Neyfeld, I.N. Okunev, M. Petrichenkov, V.V. Petrov, A. Polyansky, D.N. Pureskin, A. Rakhimov, S.I. Ruvinsky, T.V. Rybitskaya, L.M. Schegolev, A.V. Semenov, D.V. Senkov, S.S. Serednyakov, S.V. Shiyankov, D.A. Shvedov, S.V. Sinyatkin, V.V. Smaluk, A.V. Sukhanov, L. Tsukanova, A.V. Utkin, K. Yaminov
BINP SB RAS, Novosibirsk, Russia
J.H. DeLong, R.P. Fliller, G. Ganetis, H.-C. Hseuh, I. Pinayev, T.V. Shaftan, S.K. Sharma, O. Singh, Y. Tian, F.J. Willeke
BNL, Upton, Long Island, New York, USA
P.A.E. Elkiaer
Danfysik A/S, Jyllinge, Denmark

The National Synchrotron Light Source II is a third generation light source under construction at Brookhaven National Laboratory. The project includes a highly optimized 3 GeV electron storage ring, linac pre-injector and full-energy booster-synchrotron. Budker Institute of Nuclear Physics builds booster for NSLS-II. The booster should accelerate the electron beam continuously and reliably from minimal 170 MeV injection energy to maximal energy of 3.15 GeV and average beam current of 20 mA. The booster shall be capable of multi-bunch and single bunch operation. This paper summarizes the status of NSLS-II booster and the main designed parameters.

WEP204

An FFAG Accelerator for Project X

proton, lattice, linac, dynamic-aperture

1867

D.V. Neuffer, L.J. Jenner, C. Johnstone
Fermilab, Batavia, USA
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The next generation of high-energy physics experiments requires high intensity protons in the multi-GeV energy range for efficient production of secondary beams. The Fermilab long-term future requires an 8 GeV proton source to feed the Main Injector for a 2 MW neutrino beam source in the immediate future and to provide 4 MW pulsed proton beam for a future neutrino factory or muon collider. We note that a 3GeV cw linac matched to a 3–8 GeV FFAG ring could provide beam for both of these mission needs, as well as the cw 3 GeV experiments, and would be a natural and affordable scenario. We present details of possible scenarios and outline future design and research directions.

WEP205

A Gap Clearing Kicker for Main Injector

kicker, booster, controls, simulation

1870

I. Kourbanis, P. Adamson, J. Biggs, B.C. Brown, D. Capista, C.C. Jensen, G.E. Krafczyk, D.K. Morris, D.J. Scott, K. Seiya, S.R. Ward, G.H. Wu, M.-J. Yang
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Fermilab Main Injector has been operating at high Beam Power Levels since 2008 when multi-batch slip stacking became operational. In order to increase the beam power even further we have to address the localized beam loss due to beam left over in the Injection Kicker Gap during slip stacking. A set of Gap Clearing Kickers that kick any beam left in the injection gap to the beam abort have been installed during the summer of 2009 and became operational in October 2010. The kicker performance and its effect on beam losses will be described.

WEP206

An Accumulator/Pre-Booster for the Medium-Energy Electron Ion Collider at JLab

booster, ion, emittance, proton

1873

B. Erdelyi, S. Abeyratne
Northern Illinois University, DeKalb, Illinois, USA
Y.S. Derbenev, G.A. Krafft, Y. Zhang
JLAB, Newport News, Virginia, USA
S.L. Manikonda, P.N. Ostroumov
ANL, Argonne, USA

Future nuclear physics facilities such as the proposed electron ion collider (MEIC) will need to achieve record high luminosities in order to maximize discovery potential. Among the necessary ingredients is the ability to generate, accumulate, accelerate, and store high current ion beams from protons to lead ions. One of the main components of this ion accelerator complex for MEIC chain is the accumulator that also doubles as a pre-booster, which takes 200 MeV protons from a superconducting linear accelerator, accumulates on the order of 1A beam, and boosts its energy to 3GeV, before extraction to the next accelerator in the chain, the large booster. This paper describes its design concepts, and summarizes some preliminary results, including linear optics, space charge dynamics, and spin polarization resonance analysis.

WEP207

Progress Towards A Novel Compact High Voltage Electrostatic Accelerator

high-voltage, vacuum, proton, tandem-accelerator

1876

P. Beasley, O. Heid
Siemens AG, Healthcare Technology and Concepts, Erlangen, Germany

A proof-of-principle demonstrator system has been successfully built and tested. It is based on a Cockcroft-Walton (or Greinacher) cascade but has been developed using a different design philosophy and using modern materials. This can then enable this compact accelerator configuration to operate at much higher voltage gradients. This paper explores the progress made to-date and future plans to utilize the technology to develop one such concept for an energy efficient 10 MV, 100 microamp, tandem proton accelerator, with less than a 2 square meter footprint .

WEP232

A Multi Megawatt Ring Cyclotron to Search for CP Violation in the Neutrino Sector

extraction, cyclotron, cavity, proton

1924

L. Calabretta, M.M. Maggiore, D. Rifuggiato
INFN/LNS, Catania, Italy
A. Calanna
CSFNSM, Catania, Italy
L.A.C. Piazza
INFN/LNL, Legnaro (PD), Italy

A new approach to search for CP violation in the neutrino sector* is proposed by the experiment called DAEδALUS (Decay At rest Experiment for cp At Laboratory for Underground Science). DAEδALUS needs three sources of neutrino fluxes, each one located at 1.5, 8 and 20 km from the underground detector. Each source has to be supplied with a proton beam with power higher than 1, 2 and 5 MW respectively. Here we present the study for a Superconducting Ring Cyclotron able to accelerate the H²⁺ molecules and to deliver proton beam with maximum energy of 800 MeV and the required power. Although the average power for the first 2 sites are 1 and 2 MW, the 20% duty cycle, required by the experiment, has the consequence that the peak power should stay in the range 5-10 MW and a peak current of about 4.5 mA of H²⁺ is necessary. We present the parameters of the superconducting magnetic sector simulated by the code TOSCA, the isochronous magnetic field produced and the magnetic forces acting on the coils. Some evaluation on the feasibility of the ring cyclotron, the advantages and problems relates with acceleration of the H²⁺ molecules will be also presented.
* J. Alonso et al., “Expression of Interest for a Novel Search for CP Violation in the Neutrino Sector: DAEδALUS”, Jun 2010. e-Print: arXiv:1006.0260

WEP234

Longitudinal Dynamics in the EMMA ns-FFAG

acceleration, induction, extraction, resonance

1927

J.M. Garland, H.L. Owen
UMAN, Manchester, United Kingdom
N. Bliss
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J.A. Clarke, N. Marks, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work supported by the Science and Technology Facilities Council UK. Grant Number: ST/G004277/1
EMMA is the first non-scaling FFAG to be constructed, whose use of linear magnets means that the accelerating electron bunch rapidly crosses many resonances. We have modeled the capture and acceleration of bunches in the serpentine channel created by the radio-frequency cavities, and compare it to a proposed experiment in which induction cells allow slow acceleration. Two induction cores each providing ~20kV over 1.65 μs enable a number of resonance crossing experiments.

WEP242

Project X Functional Requirements Specification

linac, proton, collider, kaon

1936

S.D. Holmes, S. Henderson, R.D. Kephart, J.S. Kerby, C.S. Mishra, S. Nagaitsev, R.S. Tschirhart
Fermilab, Batavia, USA

Funding: Work supported by the Fermi Research Alliance, under contract to the U.S. Department of Energy
Project X is a multi-megawatt proton facility being designed to support intensity frontier research in elementary particle physics, with possible applications to nuclear physics and nuclear energy research, at Fermilab. A Functional Requirements Specification has been developed in order to establish performance criteria for the Project X complex in support of these multiple missions. This paper will describe the Functional Requirements for the Project X facility and the rationale for these requirements.

WEP261

Performance of the New EBIS Preinjector

ion, booster, linac, rfq

1966

J.G. Alessi, E.N. Beebe, S. Binello, C.J. Gardner, O. Gould, L.T. Hoff, N.A. Kling, R.F. Lambiase, V. LoDestro, R. Lockey, M. Mapes, A. McNerney, J. Morris, M. Okamura, A. Pendzick, D. Phillips, A.I. Pikin, D. Raparia, J. Ritter, T.C. Shrey, L. Smart, L. Snydstrup, C. Theisen, M. Wilinski, A. Zaltsman, K. Zeno
BNL, Upton, Long Island, New York, USA
U. Ratzinger, A. Schempp
IAP, Frankfurt am Main, Germany

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, and by the National Aeronautics and Space Administration.
The construction and initial commissioning phase of a new heavy ion preinjector was completed at Brookhaven in September, 2010, and the preinjector is now operational. This preinjector, using an EBIS source to produce high charge state heavy ions, provided helium and neon ion beams for use at the NASA Space Radiation Laboratory in the Fall of 2010, and gold and uranium beams are being commissioned during the 2011 run cycle for use in RHIC. The EBIS operates with an electron beam current of up to 10 A, to produce mA level currents in 10 to 40 μs beam pulses. The source is followed by an RFQ and IH linac to accelerate ions with q/m > 0.16 to an energy of 2 MeV/amu, for injection into the Booster synchrotron. The performance of the preinjector is presented, including initial operational experience for the NASA and RHIC programs.

WEP267

Estimates of the Number of Foil Hits for Charge Exchange Injection

linac, proton, ion, betatron

1975

D. Raparia
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.
For high intensity circular proton machines, one of the major limitations is the charge exchange injection foil. The number of foil hits due to circulating beam may cause the foil to fail and cause radiation due to multiple nuclear scattering and energy straggling. This paper will describe methods to estimate these quantities without going through lengthy simulations.

WEP295

Status of Laser Stripping at the SNS

laser, optics, linac, quadrupole

2035

T.V. Gorlov, A.V. Aleksandrov, V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
Y. Liu
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work was supported by SNS through UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 for the U.S. Department of Energy.
This paper presents an overview of experimental and theoretical studies on laser stripping that have been conducted up to the present time in the SNS project. The goal of this work is to develop techniques to achieve the experimental preconditions necessary for the successful realization of a future intermediate experiment on laser stripping. The experimental work consists of the tuning and measurement of H־ beam parameters in readiness for the intermediate experiment, and also takes into account the features and possibilities of the SNS accelerator.

THOCN6

Flux-coupled Cyclotron Stack: Optimization for Maximum Beam Power and Minimum Losses

cavity, coupling, cyclotron, extraction

2113

P.M. McIntyre, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: This work was supported in part by the U.S. Department of Energy under Grant DE-FG02-06ER41405
A flux-coupled stack of isochronous cyclotrons has been proposed as a driver for Accelerator-Driven Subcritical Systems (ADSS) for thorium-cycle fission power. The issues that limit beam current and phase space brightness are evaluated, including space charge tune shift, synchro-betatron coupling, orbit separation at injection and extraction, RF propagation within the accelerator envelope, RF parasitic modes, and stability of electrostatic septum operation. A design is presented that offers good optimization of these criteria.

Slides THOCN6 [5.266 MB]

THP027

Status and Development of a Proton FFAG Accelerator at KURRI for ADSR Study

proton, linac, ion, ion-source

2172

Y. Kuriyama, Y. Ishi, J.-B. Lagrange, Y. Mori, R. Nakano, T. Planche, T. Uesugi, E. Yamakawa
KURRI, Osaka, Japan
Y. Niwa, K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

In Kyoto University Research Reactor Institute (KURRI), the fixed-field alternating gradient (FFAG) proton accelerator has been constructed to make an experimental study of accelerator driven sub-critical reactor (ADSR) system with spallation neutrons produced by the accelerator. The world first ADSR experiment has been carried out in March of 2009. The proton FFAG accelerator consists of three FFAG rings; injetor (spiral sector FFAG), booster(radial sector FFAG) and main ring(radial sector FFAG), respectively. In March 2010, the experiment conducted with a thorium-loaded accelerator driven system using the proton FFAG accelerator has also been carried out. In order to increase the beam intensity of the proton FFAG accelerator, a new injector with H⁻ ions is under construction. In this scheme, H⁻ ions accelerated up to the energy of 11 MeV with a linac are injected into the main ring with charge-exchange injection. In this paper, the details of ADSR experiments with the proton FFAG accelerator at KURRI, and also the R&Ds of the accelerator will be presented.

THP056

Near Real-time ORM Measurements and SVD Matrix Generation for 10 Hz Global Orbit Feedback In RHIC

feedback, dipole, ion, damping

2226

C. Liu, R.L. Hulsart, W.W. MacKay, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty
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.
To reduce the effect of trajectory perturbations due to vibrations of the final focusing quadrupoles at RHIC, global orbit feedback was successfully prototyped during run-10. The system was tested using transfer functions between the beam position monitors and correctors obtained from the online optical model and a correction algorithm based on singular value decomposition (SVD). In run-11 we plan to self-calibrate the system using SVD matrices derived from orbit response matrix (ORM) measurements acquired real-time using the new FPGA-based signal processing. Comparisons between measurement and model and of feedback performance with the two methods are presented.

THP062

Beam Experiments Related to the Head-on Beam-beam Compensation Project at RHIC

electron, proton, cathode, lattice

2243

C. Montag, M. Bai, K.A. Drees, W. Fischer, A. Marusic, G. Wang
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.
Beam experiments have been performed in RHIC to determine some key parameters of the RHIC electron lenses, and to test the capability of verifying lattice modifications by beam measurements. We report the status and recent results of these experiments.

THP131

Injection Straight Pulsed Magnet Error Tolerance Study for Top-off Injection

kicker, septum, simulation, betatron

2366

G.M. Wang, R.P. Fliller, R. Heese, S. Kowalski, B. Parker, T.V. Shaftan, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
NSLS II is designed to work in top-off injection mode. The goal is to minimize the disturbance of the injection transient on the users. The injection straight includes a septum and four fast kicker magnets. The pulsed magnet errors will excite a betatron oscillation. This paper gives the formulas of each error contribution to the oscillation amplitude at various source points in the ring. These are compared with simulation results. Based on the simple formulas, we can specify the error tolerances on the pulsed magnets and scale it to similar machines.

THP132

Beam Diagnostics using BPM Signals from Injected and Stored Beams in a Storage Ring

storage-ring, closed-orbit, simulation, betatron

2369

G.M. Wang, W.X. Cheng, R.P. Fliller, R. Heese, T.V. Shaftan, O. Singh, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. For top-off injection mode, the storage ring always has the stored beam and injected beam. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use a BPM with special electronics in NSLS II storage ring to retrieve the injected beam trajectory with the SVD method. The BPM has the capability to measure bunch-by-bunch beam position. We also need another system to measure the bunch-by-bunch beam current. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.

THP134

Lifetime Measurement with Pseudo Moveable Septum in NSLS X-ray Ring

septum, closed-orbit, kicker, vacuum

2375

G.M. Wang, J. Choi, R. Heese, S.L. Kramer, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
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 and starts to commission in 2014. The beam injection works with two septa and four fast kicker magnets in an injection section. To improve the injection stability and reproducibility, we plan to implement a slow local bump on top of the fast bump so that the fast kicker strength is reduced. This bump works as a pseudo movable septum. We can also use this ‘movable’ septum to measure the storage ring beam partial lifetime resulting from the septum edge and possibly increasing the lifetime by moving the stored beam orbit away from the edge. We demonstrate the feasibility of this idea, by implementing DC bump in NSLS X-ray ring. We report the results of beam lifetime measurements as a function of the amplitude of this bumped orbit relative to the septum and the idea of a slow bump that could reduce the fast bump magnet strengths.

THP135

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

septum, kicker, storage-ring, vacuum

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.

THP178

Design of the MAX IV Ring Injector and SPF/FEL Driver

linac, FEL, electron, simulation

2447

S. Thorin, M. Eriksson, M.A.G. Johansson, D. Kumbaro, F. Lindau, L. Malmgren, J.H. Modéer, M. Sjöström, S. Werin
MAX-lab, Lund, Sweden
D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The MAX IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (in phase 2). Compression is done in two double achromats with positive R56. The natural second order momentum compaction, T566, from the achromats is used together with weak sextupoles to linearise longitudinal phase space, leaving no need for a linearising harmonic cavity. The design of the linac focuses on flexibility, simplicity and stability, while keeping the costs low. The accelerator structures have been ordered, as well as modulator/klystrons. The linac will be the first accelerator to be assembled and commissioned in the MAX IV project, starting mid 2012.

THP186

Lattice Design for ERL Options at SLAC

linac, emittance, lattice, extraction

2465

Y. Nosochkov, Y. Cai, X. Huang, M.-H. Wang
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract number DE-AC02 76SF00515.
SLAC is investigating long-range options for building a high performance light source machine while reusing the existing linac and PEP-II tunnels. One previously studied option is the PEP-X low emittance storage ring. The alternative option is based on a superconducting Energy Recovery Linac (ERL) and the PEP-X design. The ERL advantages are the low beam emittance, short bunch length and small energy spread leading to better qualities of the X-ray beams. Two ERL configurations differed by the location of the linac have been studied. Details of the lattice design and the results of beam transport simulations with the coherent synchrotron radiation effects are presented

THP189

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

lattice, dynamic-aperture, sextupole, insertion

2471

F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
BNL, Upton, 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

lattice, quadrupole, insertion, insertion-device

2474

F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
BNL, Upton, 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.

THP191

Recent Progress in Injector Improvement of SPEAR 3

booster, quadrupole, linac, storage-ring

2477

K. Tian, W.J. Corbett, D. Dell'Orco, D. Ernst, S.M. Gierman, J.A. Safranek, J.F. Schmerge, B. Scott
SLAC, Menlo Park, California, USA

The frequent injection and high current operation of SPEAR 3 storage ring requires high stability of the injector system at the Stanford Synchrotron Radiation Laboratory (SSRL). The lattice of linac-to-booster (LTB) transport line was not well understood and controlled prior to this work. In this paper, we discuss the significant efforts that have been made to improve the performance of the LTB. A method to correct the distortion of the closed orbit in the booster by moving 2 quadrupoles is also presented.

THP213

Traveling Wave Electron Linac for Synchrotron Injector

linac, electron, synchrotron, simulation

2519

S.V. Kutsaev, K.I. Nikolskiy, N.P. Sobenin
MEPhI, Moscow, Russia

In this paper the project design of a travelling wave electron linac used as an injector to synchrotron in Lebedev Physical Institute of the Russian Academy of Sciences (LPI RAS) is presented. The injected beam to the synchrotron should have very small emittance and energy spectrum. Thus, the buncher design is an essential question in this problem. One of the best output beam parameters can be achieved by using a waveguide buncher with the non-uniform parameters. The proposals of optimal buncher design and beam dynamics calculation results are presented.

THP214

Pulsed Multipole Injection for the MAX IV Storage Rings

storage-ring, multipole, septum, sextupole

2522

S.C. Leemann
MAX-lab, Lund, Sweden

The MAX IV facility presently under construction will include two storage rings for the production of synchrotron radiation. The 3 GeV ring will house insertion devices for the production for x-rays while the 1.5 GeV ring will serve UV and IR users. Both rings will be operated at a constant 500 mA of stored current with top-up shots supplied by the 3.5 GeV MAX IV linac acting as a full-energy injector. So far, injection into both storage rings has been designed using a conventional approach: a closed four-kicker injection bump brings the stored beam to the septum blade where the injected bunches are captured in a single turn. Recently, studies have been carried out to investigate the feasibility of using a pulsed multipole for injection into the storage rings. Pulsed multipole injection does not require an injection bump and has the potential to make top-up injection transparent to users. This paper reports on these studies and summarizes requirements for the pulsed sextupole magnet to be installed for injection into the MAX IV storage rings.

THP216

Progress with NSLS-II Injection Straight Section Design

septum, kicker, storage-ring, vacuum

2528

T.V. Shaftan, A. Blednykh, W.R. Casey, L.R. Dalesio, R. Faussete, M.J. Ferreira, R.P. Fliller, G. Ganetis, R. Heese, H.-C. Hseuh, P.K. Job, E.D. Johnson, B.N. Kosciuk, S. Kowalski, S.L. Kramer, D. Padrazo, B. Parker, I. Pinayev, S.K. Sharma, O. Singh, C.J. Spataro, G.M. Wang, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by U.S. DOE, Contract No.DE-AC02-98CH10886
NSLS-II injection straight section consists of the pulsed and DC/Slow bumps, septa system, beam trajectory correction and diagnostics systems. In this paper we discuss overall injection straight layout, preliminary element designs, specifications for the pulsed and DC magnets and their power supplies, vacuum devices and chambers and diagnostics devices.

THP217

Frequent Fill Top-Off Injection at SPEAR3

controls, feedback, linac, power-supply

2531

J.J. Sebek, S. Allison, S.M. Gierman, X. Huang, J.A. Safranek, J.F. Schmerge, K. Tian, C. Wermelskirchen
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76-SF00515
SPEAR3 beam is now delivered to users in a "frequent fill" mode in which beam is injected into the storage ring, with beam-line shutters open, on a periodic schedule so that the beam current is kept constant to within 1% of its average value. This goal was achieved with the constraints of having the SPEAR3 injector run at very high reliability and ensuring that there would be no challenges to the beam containment system in this operational mode. This paper presents the accelerator development, the hardware changes, and the software developed to implement this operational mode.

FROBN3

Project X - New Multi Megawatt Proton Source at Fermilab

linac, proton, cavity, collider

2566

S. Nagaitsev
Fermilab, Batavia, USA

Fermilab plans to replace its present injection complex consisting of a pulsed linac and 15 Hz Booster with a new injection complex based on a superconducting CW linac. This new proton source should boost the power of the Main Injector to 2 MW and enable new experiments with a high power proton beam in the range of 1-3 GeV. The speaker will present recent developments from the Fermilab Project X R&D.

Slides FROBN3 [2.018 MB]