New version page

PARMELA

This preview shows page 1-2-19-20 out of 20 pages.

View Full Document
View Full Document

End of preview. Want to read all 20 pages?

Upload your study docs or become a GradeBuddy member to access this document.

View Full Document
Unformatted text preview:

Slide 1OutlinePresent PARMELA StatusWho uses PARMELA?What are the main applications of PARMELA?Main Features of PARMELAMain Features of PARMELA (cont.)How does PARMELA calculate space-charge (SC)?Slide 9PARMELA calculates wakefields.PARMELA has a 1-D CSR routine.CSR Code ComparisonPARMELA has been validated through operating facilities.PARMELA has been compared to measurements.PARMELA has been compared to other codes.PARMELA has been compared to other codes (cont.)LANL Comparison of PARMELA and MAFIA 2D PICSlide 18PARMELA and other codes need improved modeling of the cathode physics!Areas of Improvement / Collaborations1PARMELA Bob GarnettLos Alamos National LaboratoryWorkshop on High Average Power & High Brightness BeamsUCLANovember 8-10, 20042Outline•Present Status of PARMELA•PARMELA Code Description- Main Features- Additional FeaturesSpace ChargeWakefields and BBUCSR•Validation, Benchmarking, & Limitations•Areas of Improvement / Collaborations?3Present PARMELA Status•PARMELA is both proprietary and Government owned:- Copyright asserted and licensed January 1999 through agreement between DOE and UC/LANL.- Licenses issued by LANL Technology Transfer Division.- Licensing fees collected:U.S. Gov’t, Nonprofits, Academic Institutions – No fee.15% - TT Division, 35% - Individual Innovator(s), 50% - LAACG Support •Executable code is distributed through the LAACG: - Web-based distribution through an FTP server.- Source code written in Fortran 95 / Lahey LF95 Compiler.- MS Windows operating environment only for now. Linux next. Windows NT (version 4 and higher) , 2000, XP- Code documentation and user manual exist.- User help available by contacting the LAACG members.- Configuration control also performed by the LAACG.4Who uses PARMELA?•As of FY 2003, 371 Users World-Wide, 206 U.S. Users•Government-Funded Labs: 48%SLAC, TJAF, ORNL, LANL, LBNL, LLNL, ANL, BNL, Fermilab, NRL, NASA, SANDIA•Academic Institutions: 28%Stanford, MIT, Cornell, U. of Maryland, Duke, MSU, U. of Michigan, U. of Illinois, Illinois Inst. Of Tech., Rensselaer, Vanderbilt, U. of Nevada…•Commercial Companies: 20%Boeing North American, SAIC, Advanced Energy Systems, Titan,Tech-X Corp., Siemens, Varian, Eaton, Axcelis Technologies,Teledyne Electronic Technologies, KLA-Tencor…•Private Individuals: 4%All major players in the high-power FEL business use it!SLAC, JLAB, Boeing, etc.5What are the main applications of PARMELA?•Design and Simulation of FELs•Commercial Linear Accelerator Applications:Medical LinacsFood SterilizationIon Implanters•Photoinjectors•Beamlines / Transport Systems•High-Intensity Electron and Ion Linacs6Main Features of PARMELA• Integrates macroparticle trajectories through the fields in 3-D using phase (time) as the independent variable.• Can be used to simulate beam dynamics of beam transport and accelerator systems (Normal Conducting and Superconducting).• Includes accelerating, focusing, space-charge, CSR and wake fields.• Can read in 2-D and 3-D field distributions:RF fields generated by Superfish or MAFIAStatic magnetic fields from Poisson• Can be run in real-time or batch mode.Execution time varies as a function of macroparticle number, time step, type of space-charge calculation, CSR, etc.7Main Features of PARMELA (cont.)• Large number of beam line, accelerator cavity, and other elements are modeled:DRIFT, SOLENOID, QUAD, CATHODE, ESQUAD, BEND,BUNCHER, CHOPPER, STRIPPER, RF CAVITY, TANK,DTLCELL, TRWAVE, WIGGLER, SEXTUPOLE, COIL• Includes random and systematic alignment errors facilitating studies of performance for off-normal (error) conditions. • Cathode modeling included. This allows simulation up through the wiggler. • Several initial beam distributions can be generated:- K-V Distribution- Uniform Spatial Distribution- Gaussian or Uniform With No Energy Spread including the “Quiet Start” method to eliminate shot noise (correlations).- Can read in a EGUN or ISIS distribution.8How does PARMELA calculate space-charge (SC)?SCHEFF (2-D)•2-dimensional r-z PIC Method:- Transform to beam rest frame.- Divide beam volume into a grid of discrete r and z values.- For each charge ring at (ri, zj) use a Green’s function method to approximate Er,i and Ez,j due to every other ring at (rk, zl).- Each macroparticle receives an x, y, and z impulse in the rest frame.•Effects of neighboring bunches can be included.-dependent auto-meshing and field interpolation.•Effects of conducting-wall image charges can be included.•Fast algorithm compared to some other methods.•Accurate even with small number of macroparticles – Good smoothing due to 2-D.•Agrees well with other SC algorithms such as 3-D point-to-point. Also used in our other codes where it has been benchmarked.9How does PARMELA calculate space-charge (SC)?SPCH3D (3-D)•Fast 3-D PIC routine written by Rob Ryne for IMPACT.See Ji Qiang, et al., NIM A 457 (2001) 1-11 - Uses a cloud-in-cell algorithm for charge deposition on the grid and for field interpolation.- Field solution is based on a convolution of the charge density and the Green’s function of the potential.- The 3-D convolution is performed using a FFT-based algorithm to implement the open boundary conditions.See R.W. Hockney and J.W. Eastwood, “Computer Simulation Using Particles,”•Also has -dependent auto-meshing.•Includes effects of image charges for a flat cathode.•Larger number of macroparticles required to minimize numerical noise effects.•Fast, but not as fast as SCHEFF.10PARMELA calculates wakefields.•PARMELA can do a single-bunch beam loading calculation to correct particle energies due to the effects of wakefields:- Based on a TBCI (MAFIA) calculation for a Gaussian longitudinal beam distribution.- The change in energy of a single particle is parameterized using fitted coefficients for a wakefield from a side-coupled cavity scaled to correct for frequency.•PARMELA does not calculate beam breakup (BBU) effects.- This is done as a separate analysis after the accelerator structure is known.- Use MAFIA and CUMBBU* codes, or others.- Iterate design to minimize these effects. *R.L. Gluckstern, R.K. Cooper, and P.J. Channell, Part. Accel. 16, 125 (1985)11PARMELA has a 1-D CSR routine.•Present implementation uses an algorithm developed at Boeing. Implemented by Lloyd Young.See B. Koltenbah, et al., NIM A 487 (2002) 249 – 267.•This approach assumes the beam bunch is a


Loading Unlocking...
Login

Join to view PARMELA and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view PARMELA and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?