Search found 1924 matches

by michael_borland
05 Sep 2023, 18:18
Forum: Ring Tracking
Topic: Ring tracking with ciwggler element
Replies: 6
Views: 963

Re: Ring tracking with ciwggler element

Weijie, Thanks for posting this problem. It was interesting to analyze. (See attached for details.) I see two issues with the design. First, with only one rf cavity in the ring, the optics is badly distorted by the strong energy variation introduced by the wigglers; I addressed this by putting an rf...
by michael_borland
29 Aug 2023, 09:54
Forum: General
Topic: Read off the one-turn matrix from the result files?
Replies: 1
Views: 823

Re: Read off the one-turn matrix from the result files?

Gunn, There are two ways to get this. You can supply a filename for the final output in the run_setup command. You'll find the Rij values in parameters in that output file. This is convenient if you are varying something in the system and want to see how the matrix elements change as a function of t...
by michael_borland
28 Aug 2023, 12:47
Forum: Momentum Aperture
Topic: Touschek lifetime calculation in presence of magnet errors in a ring
Replies: 2
Views: 460

Re: Touschek lifetime calculation in presence of magnet errors in a ring

Monika, You can use the sddssplit command to split the multi-page output files into many single-page files. Pairs of single-page files can then be fed to touschekLifetime. Once done running touschekLifetime, you can use sddscombine to combine the touschek lifetime results into a single file, which i...
by michael_borland
28 Aug 2023, 12:43
Forum: Ring Tracking
Topic: simulation speed when there are multi-bunches and muti-IBS element
Replies: 3
Views: 592

Re: simulation speed when there are multi-bunches and muti-IBS element

Chao,

I wonder if in the case using bunch duplication you are setting the use_bunched_mode flag?

I would expect using N bunches to slow things down, because there is N times as much interprocess communication (assuming that IBS is a dominant factor in the simulation).

--Michael
by michael_borland
28 Aug 2023, 12:38
Forum: Optimization and Matching
Topic: Correctors of a transfer line
Replies: 5
Views: 913

Re: Correctors of a transfer line

You should use the corrected emittance in the optimization, but also be sure that you are controlling the residual dispersion. In general for off-axis injection into a ring, you should match the dispersion at the end of the last septum or kicker to zero. For on-axis injection, match the dispersion t...
by michael_borland
28 Aug 2023, 12:36
Forum: Ring Tracking
Topic: Transient beam loading with passive Harmonic cavity
Replies: 7
Views: 4758

Re: Transient beam loading with passive Harmonic cavity

Pradeep,

I can't find that example. Can you post it?

--Michael
by michael_borland
28 Aug 2023, 12:19
Forum: Linac Tracking
Topic: Energy of different bunches in multi-bunch simulations
Replies: 1
Views: 570

Re: Energy of different bunches in multi-bunch simulations

Wei-Hou, Your file elegant.erl changes the DY values for the misalignment elements, so I would expect to see different vertical centroids for the bunches, which is in fact what's seen. There's nothing that introduces a significant variation in energy between the bunches, since dipole modes have a we...
by michael_borland
16 Aug 2023, 13:01
Forum: Linac Tracking
Topic: Problems on running Pelegant with FTRFMODE
Replies: 8
Views: 801

Re: Problems on running Pelegant with FTRFMODE

Wei-Hou, There seems to be a bug in Pelegant that the bunch output from &bunched_beam gets 0 for the IDSlotsPerBunch parameter. I'll look into it. Using a zero-length drift lattice to get output via &run_setup's output parameter is a good workaround. Also, there are scripts called generateBunch and ...
by michael_borland
16 Aug 2023, 12:52
Forum: Optimization and Matching
Topic: Phase advance
Replies: 1
Views: 435

Re: Phase advance

In order for phase advances to be available, you have to include a &twiss_output command with output_at_each_step=1.

--Michael
by michael_borland
16 Aug 2023, 12:47
Forum: Ring Tracking
Topic: model of ring by several ilmatrix elements?
Replies: 4
Views: 656

Re: model of ring by several ilmatrix elements?

Chao, The IBS simulation method is summarized in https://accelconf.web.cern.ch/IPAC2015/papers/mopma012.pdf The calculation of the emittance growth rates is based on Piwinski's method. This is computed in segments of the lattice and then applied to the particle distribution either as random scatteri...