63 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Accphy"  
Results: 1 - 24 next
open access

Digitral Down Conversion Technology for Tevatron Beam Line Tuner at FNAL

Description: Fermilab is presently in Run II collider operations and is developing instrumentation to improve luminosity. Improving the orbit matching between accelerator components using a Beam Line Tuner (BLT) can improve the luminosity. Digital Down Conversion (DDC) has been proposed as a method for making more accurate beam position measurements. Fermilab has implemented a BLT system using a DDC technique to measure orbit oscillations during injections from the Main Injector to the Tevatron. The output … more
Date: March 17, 2008
Creator: Schappert, W.; Lorman, E.; Scarpine, V.; Ross, M.C.; Sebek, J.; Straumann, T. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Active Damping of the E-P Instability at the Los Alamos Proton Storage Ring

Description: A prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability has been developed and successfully tested at the Los Alamos Proton Storage Ring (PSR). This system was able to improve the instability threshold by approximately 30% (as measured by the change in RF buncher voltage at instability threshold). The feedback system configuration, setup procedures, and optimization of performance are described. Results of several experimental tests… more
Date: March 17, 2008
Creator: Macek, R. J.; Assadi, S.; Byrd, J. M.; Deibele, C. E.; Henderson, S. D.; Lee, S. Y. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Microbunching and Beam Break Up in DUV FEL Accelerator

Description: We present the results of electron beam longitudinal modulation studies in the DUV-FEL accelerator. For bunch length determination we used the 'zero-phasing' method, based on a measurement of the chirped electron bunch energy spectra. The measurements revealed a spiky structure in the longitudinal phase space [1]. A model based on space charge effect is considered [2] to explain of the obtained phenomena. The analysis of the energy spectra has shown a sensitivity of the structure to the electro… more
Date: March 17, 2008
Creator: Shaftan, T.; Carr, L.; Loos, H.; Sheehy, B.; Graves, William S.; Huang, Z. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Lattice with Larger Momentum Compaction for the NLC Main Damping Rings

Description: Previous lattice designs for the Next Linear Collider Main Damping Rings [1] have met the specifications for equilibrium emittance, damping rate and dynamic aperture. Concerns about the effects of the damping wiggler on the beam dynamics [2] led to the aim of reducing the total length of the wiggler to a minimum consistent with the required damping rate, so high-field dipoles were used to provide a significant energy loss in the arcs. However, recent work has shown that the wiggler effects may … more
Date: March 17, 2008
Creator: Woodley, M.; Raubenheimer, Tor O.; Wu, J.; Wolski, A. & /SLAC /LBL, Berkeley
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Parallel Code for Lifetime Simulations in Hadron Storage Rings in the Presence of Parasitic Beam-Beam Interactions

Description: The usual approach to predict particle loss in storage rings in the presence of nonlinearities consists in the determination of the dynamic aperture of the machine. This method, however, will not directly predict the lifetimes of beams. We have developed a code which can, by parallelization and careful speed optimization, predict lifetimes in the presence of 100 parasitic beam-beam crossings by tracking > 10{sup 10} particles-turns. An application of this code to the anti-proton lifetime in … more
Date: March 17, 2008
Creator: Kabel, A. C.; Cai, Y.; Erdelyi, B.; Sen, T. & Xiao, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Magnetic Measurements and Simulations for a 4-magnet Dipole Chicane for the International Linear Collider

Description: T-474 at SLAC is a prototype BPM-based energy spectrometer for the ILC. We describe magnetic measurements and simulations for the 4-magnet chicane used in T-474.
Date: December 17, 2007
Creator: Schreiber, H. J.; Viti, M.; /DESY; Duginov, V. N.; Kostromin, S. A.; Morozov, N. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Beam Dynamics Studies for the SPARC Project

Description: The aim of the SPARC project, is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments. We discuss in this paper the status of the beam dynamics simulation activities.
Date: March 17, 2008
Creator: Ferrario, M.; Biagini, Maria E.; Boscolo, M.; Fusco, V.; Guiducci, S.; Migliorati, M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Positron Beam Propagation in a Meter Long Plasma Channel

Description: Recent experiments and simulations have shown that positron beams propagating in plasmas can be focused and also create wakes with large accelerating gradients. For similar parameters, the wakes driven by positron beams are somewhat smaller compared to the case of an electron beam. Simulations have shown that the wake amplitude can be increased if the positron beam is propagated in a hollow plasma channel (Ref. 1). This paper, compares experimentally, the propagation and beam dynamics of a posi… more
Date: March 17, 2008
Creator: Marsh, K. A.; Blue, B. E.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Decker, F. -J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Investigation of Microwave Instability on Electron Storage Ring TLS

Description: With the planned installation of a superconducting rf system, the new operation mode of TLS, the electron storage ring at NSRRC, is expected to double the beam intensity. Several accelerator physics topics need to be examined. Beam instability of single-bunch longitudinal microwave instability is one of these topics. We consider two approaches to measure the effective broad band impedance. We compare these measurement results with each other and to old data [Ref.1]. We calculate the threshold c… more
Date: May 17, 2005
Creator: Wang, M.-H. & Chao, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

Description: Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagno… more
Date: March 17, 2008
Creator: Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; Borden, Michael J.; O'Hara, James F.; McCrady, Rodney C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Breakdown Limits on Gigavolt-per-Meter Electron-Beam-Driven Wakefields in Dielectric Structures

Description: First measurements of the breakdown threshold in a dielectric subjected to GV/m wakefields produced by short (30-330 fs), 28.5 GeV electron bunches have been made. Fused silica tubes of 100 {micro}m inner diameter were exposed to a range of bunch lengths, allowing surface dielectric fields up to 27 GV/m to be generated. The onset of breakdown, detected through light emission from the tube ends, is observed to occur when the peak electric field at the dielectric surface reaches 13.8 {+-} 0.7 GV/… more
Date: June 17, 2008
Creator: Thompson, M. C.; Badakov, H.; Cook, A. M.; Rosenzweig, J. B.; Tikhoplav, R.; Travish, G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coupling Correction and Beam Dynamics at Ultralow Vertical Emittance in the ALS

Description: For synchrotron light sources and for damping rings of linear colliders it is important to be able to minimize the vertical emittance and to correct the spurious vertical dispersion. This allows one to maximize the brightness and/or the luminosity. A commonly used tool to measure the skew error distribution is the analysis of orbit response matrices using codes like LOCO. Using the new Matlab version of LOCO and 18 newly installed power supplies for individual skew quadrupoles at the ALS the em… more
Date: March 17, 2008
Creator: Steier, Christoph; Robin, D.; Wolski, A.; Portmann, G.; Safranek, J. & /LBL, Berkeley /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Parallel Simulation Algorithms for the Three Dimensional Strong-Strong Beam-Beam Interaction

Description: The strong-strong beam-beam effect is one of the most important effects limiting the luminosity of ring colliders. Little is known about it analytically, so most studies utilize numeric simulations. The two-dimensional realm is readily accessible to workstation-class computers (cf.,e.g.,[1, 2]), while three dimensions, which add effects such as phase averaging and the hourglass effect, require vastly higher amounts of CPU time. Thus, parallelization of three-dimensional simulation techniques is… more
Date: March 17, 2008
Creator: Kabel, A. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron Cloud Mitigation in the Spallation Neutron Source Ring

Description: The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H{sup -} injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field an… more
Date: March 17, 2008
Creator: Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Wakefield Calculations for the LCLS in Multbunch Operation

Description: Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well, although not yet routinely. In this re… more
Date: October 17, 2011
Creator: Bane, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Compact Ring Design with Tunable Momentum Compaction

Description: A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and predamping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercel… more
Date: May 17, 2012
Creator: Sun, Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Super-B Project Accelerator Status

Description: The SuperB project is an international effort aiming at building in Italy a very high luminosity e{sup +}e{sup -} (10{sup 36} cm{sup -2} sec{sup -1}) asymmetric collider at the Y(4S) energy in the CM. The accelerator design has been extensively studied and changed during the past year. The present design, based on the new collision scheme, with large Piwinski angle and the use of 'crab waist' sextupoles already successfully tested at the DA{Phi}NE {Phi}-Factory at LNF Frascati, provides larger … more
Date: August 17, 2011
Creator: Biagini, M.E.; Alesini, D.; Boni, R.; Boscolo, M.; Demma, T.; Drago, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A New Green's Function for the Wake Potential Calculation of the SLAC S-band Constant Gradient Accelerating Section

Description: The behavior of the longitudinal wake fields excited by a very short bunch in the SLAC S-band constant gradient accelerating structures has been studied. Wake potential calculations were performed for a bunch length of 10 microns using the author's code to obtain a numerical solution of Maxwell's equations in the time domain. We have calculated six accelerating sections in the series (60-ft) to find the stationary solution. While analyzing the computational results we have found a new formula f… more
Date: February 17, 2012
Creator: Novokhatski, A,
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kirchhoff's Integral Representation and a Cavity Wake Potential

Description: A method is proposed for the calculation of the short-range wake field potentials of an ultra-relativistic bunch passing near some irregularities in a beam pipe. The method is based on the space-time domain integration of Maxwell's equations using Kirchhoff's formulation. We demonstrate this method on two cases where we obtain the wake potentials for the energy loss of a bunch traversing an iris-collimator in a beam pipe and for a cavity. Likewise, formulas are derived for Green's functions tha… more
Date: February 17, 2012
Creator: Novokhatski, Alexander
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coupler Studies for PBG Fiber Accelerators

Description: Photonic band gap (PBG) fiber with hollow core defects are being designed and fabricated for use as laser driven accelerators because they can provide gradients of several GeV/m for picosecond pulse lengths. We expect to produce fiber down to {lambda} = 1.5-2.0 {micro}m wavelengths but still lack a viable means for efficient coupling of laser power into such structures due to the very different character of the TM-like modes from those used in the telecom field and the fact that the defect must… more
Date: August 17, 2011
Creator: England, J.; Ng, C.; Noble, R.; Spencer, J.; Wu, Z. & Xu, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen