Paper  Title  Page 

TUOBAB02  Experimental Characterization of the Transverse Phase Space of a 60MeV Electron Beam through a Compressor Chicane  788 


Funding: U. S. DOE of Sciences
Space charge and coherent synchrotron radiation may deteriorate electron beam quality when the beam passes through a magnetic bunch compressor. This paper presents the transverse phasespace tomographic measurements for a compressed beam at 60 MeV, around which energy the first stage of magnetic bunch compression takes place in most advanced linacs. Transverse phasespace bifurcation of a compressed beam is observed at that energy, but the degree of the space chargeinduced bifurcation is appreciably lower than the one observed at 12 MeV. The Trafic4 simulation confirms the observation.
The paper was published at PRSTAB, November 2006 

Slides  
TUZBC01  Towards Simulation of Electromagnetics and Beam Physics at the Petascale  889 


Funding: Work supported by DOE contract DEAC0276SF00515. Under the support of the U. S. DOE SciDAC program, SLAC has been developing a suite of 3D parallel finiteelement codes aimed at highaccuracy, highfidelity electromagnetic and beam physics simulations for the design and optimization of nextgeneration particle accelerators. Running on the latest supercomputers, these codes have made great strides in advancing the state of the art in applied math and computer science at the petascale that enable the integrated modeling of electromagnetics, selfconsistent ParticleInCell (PIC) particle dynamics as well as thermal, mechanical, and multiphysics effects. This paper will present 3D results of trapped mode calculations in an ILC cryomodule and the modeling of the ILC Sheet Beam klystron, shape determination of superconducting RF (SCRF) cavities and multipacting studies of SCRF HOM couplers, as well as 2D and preliminary 3D PIC simulation results of the LCLS RF gun. 

Slides  
TUODC03  Parallel Finite Element ParticleInCell Code for Simulations of Spacecharge Dominated BeamCavity Interactions  908 


Funding: U. S. DOE contract DEAC00276SF00515 Over the past years, SLAC's Advanced Computations Department (ACD) has developed the parallel finite element particleincell code Pic3P (Pic2P) for simulations of beamcavity interactions dominated by spacecharge effects. As opposed to standard spacecharge dominated beam transport codes, which are based on the electrostatic approximation, Pic3P (Pic2P) includes spacecharge, retardation and boundary effects as it selfconsistently solves the complete set of MaxwellLorentz equations using higherorder finite element methods on conformal meshes. Use of efficient, largescale parallel processing allows for the modeling of photoinjectors with unprecedented accuracy, aiding the design and operation of the nextgeneration of accelerator facilities. Applications to the Linac Coherent Light Source (LCLS) RF gun are presented. 

Slides  
TUPAS095  Experiments with a DC Wire in RHIC  1859 


Funding: Work supported by U. S. DOE under contract No DEAC0298CH1886. A DC wire has been installed in RHIC to explore the longrange beambeam effect, and test its compensation. We report on experiments that measure the effect of the wire's electromagnetic field on the beam's lifetime and tune distribution, and accompanying simulations. 

WEPMS048  Modelling Imperfection Effects on Dipole Modes in TESLA Cavity  2454 


Funding: Work supported by DOE contract DEAC0276SF00515 The actual cell shape of the TESLA cavities differ from the ideal due to fabrication errors, the addition of stiffening rings and the frequency tuning process. Cavity imperfection shift the dipole mode frequencies and alter the Qext's from those computed for the idea cavity. A Qext increase could be problematic if its value exceeds the limit required for ILC beam stability. To study these effects, a cavity imperfection model was established using a mesh distortion method. The eigensolver Omega3P was then used to find the critical dimensions that contribute to the Qext spread and frequency shift by comparing predictions to TESLA cavity measurement data. Using the imperfection parameters obtained from these studies, artificial imperfection models were generated and the resulting wakefields were used as input to the beam tracking code Lucretia to study the effect on beam emittance. In this paper, we present the results of these studies and suggest tolerances for the cavity dimensions. 

THPAS062  Recent Progress in a BeamBeam Simulation Code for Circular Hadron Machines  3627 


Over the past years, we have developed a set of codes (PLIBB and NIMZOVICH) applicable to weakstrong and strongstrong beambeam interactions in hadron machines. We have unified these codes into a single application and augmented the modeled physics to include arbitraryorder magnetic elements, noise sources and wire compensators; algorithmic improvements include diferentialalgebraic methods, thick magnetic elements, and a fullycoupled, sixdimensional and symplectic treatment of lumped sections. A novel weightedmacroparticle approach allows for the immediate calculation of very low beam loss rates by particle tracking. The parallelization scheme of the code allows for a highly efficient simulation of colliders with a high number of parasitic crossings and/or pronounced hourglass effect in the IP. Areas of applicability include the LHC and the wirecompensation experiments performed at RHIC. Typical results will be presented. 