Last modified: Wed May 1 14:20:48 PDT 2019
SLAC National Accelerator Laboratory LCLS-II Lattice Description
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This was the home page of the lattice descriptions of the Linac Coherent Light Source II (LCLS-II) Accelerator project. These materials are now DEPRECATED . Please now (as of April 24, 2019) refer to the LCLS lattice home page, where you will find the lattice files for both normal conducting (NC) and the new superconducting (SC) beampaths of the combined LCLS accelerator complex.

The lattice descriptions are expressed in the Methodical Accelerator Design (MAD) language (version 8), and in ELEGANT.

MAD Input Files

The following are the LCLS-II MAD input files in SLAC's CVS:

File Description MAD Input file name
Main command file LCLS2sc_main.mad8
Matching command file LCLS2sc_match.mad8
Master definitions LCLS2sc_master.xsif
Common definitions common.xsif
Cryomodule definitions CM.xsif
Injector + Laser Heater + collimation section 0 definitions INJ.xsif
Post-LH diagnostic line definitions DIAG0.xsif
Bunch compressor 1 + collimation section 1 definitions BC1.xsif
Bunch compressor 2 + emittance diagnostic section definitions BC2.xsif
Linac extension definitions EXT.xsif
Bypass dogleg definitions DLBM.xsif
Bypass line definitions BYP.xsif
3-way beam spreader definitions SPRD.xsif
SXR/HXR LTU + dump area definitions LTU.xsif
SXR/HXR undulator area definitions UND.xsif
SXR/HXR safety dump line definitions SFT.xsif
DASEL definitions DASEL.xsif
Beamline definitions BSYsc.xsif
SXR XTES system definitions SXTES.xsif
LCLS Main command file LCLS2cu_main.mad8
LCLS Matching command file LCLS2cu_match.mad8
LCLS Master definitions LCLS2cu_master.xsif
LCLS definitions LCLS2cu.xsif
LCLS Linac 1 as built LCLS_L1.xsif
LCLS Linac 1 for Elegant LCLS_L1e.xsif
LCLS Linac 2 as built LCLS_L2.xsif
LCLS Linac 2 for Elegant LCLS_L2e.xsif
LCLS Linac 3 as built LCLS_L3.xsif
LCLS Linac 3 for Elegant LCLS_L3e.xsif
LCLS BSY to SXR definitions CUSXR.xsif
LCLS BSY to A-line definitions ALINE.xsif
LCLS Beamline definitions BSYcu.xsif
HXR XTES system definitions HXTES.xsif

MAD Output Files

The MAD output results of the above files, are in directories under /afs/slac/www/grp/ad/model/output/lcls2/mad/. Those output directories containing files resulting from official lattice releases, are named after their release date in the form ddMMMyy, eg "20MAR15". The date string is also used as the CVS tag of their release. The data of official releases should also be found in the Oracle database (see below). Additionally, the latest output is always in /afs/slac/www/grp/ad/model/output/lcls2/mad/latest/. Note that the "latest" link may contain results from lattice development following the last release - so it is not necessarily the output of the most recent official release. That is, "latest" may contain follow-ups, or addenda, to files in an official release.

ELEGANT Input Files

The following are the LCLS-II ELEGANT input files in SLAC's CVS:

File Description ELEGANT Input file name
L0 to SXR dump commands LCLS2scS.ele
L0 to SXR dump definitions LCLS2scS.lte
LH undulator MATRIX definition UMHTR.rmat
SXR undulator MATRIX definition UMASXh.rmat
SXR phase shifter MATRIX definition PSSXh.rmat
L0 to HXR dump commands LCLS2scH.ele
L0 to HXR dump definitions LCLS2scH.lte
XLEAP wiggler MATRIX definition WIGXL.rmat
HXR undulator MATRIX definition UMAHXh.rmat
HXR phase shifter MATRIX definition PSHXh.rmat
L0 to BSY dump commands LCLS2scD.ele
L0 to BSY dump definitions LCLS2scD.lte
Post-LH diagnostic line commands DIAG0.ele
Post-LH diagnostic line definitions DIAG0.lte
DIAG0 QDG001 vertical offset MATRIX definition DYQDG001.rmat
DIAG0 QDG003 vertical offset MATRIX definition DYQDG003.rmat
100 pC input beam definition (F. Zhou) FZ_100pC_15OCT15.sdds
1.3 GHz longitudinal wakefield definition zWake_1.3GHz_OneCavity_dz2um_TESLA2003-09.sdds
1.3 GHz transverse wakefield definition xWake_1.3GHz_OneCavity_dz2um_TESLA2003-09.sdds
3.9 GHz longitudinal wakefield definition zWake_3.9GHz_OneCavity_dz2um_TESLA2004-01.sdds
3.9 GHz transverse wakefield definition xWake_3.9GHz_OneCavity_dz2um_TESLA2004-01.sdds
resistive wall wakefield definition Al_24.5mmR_100nm3mm.sdds
resistive wall wakefield definition Cu_20.6mmR_100nm3mm.sdds
resistive wall wakefield definition SS_24.5mmR_100nm3mm.sdds
resistive wall wakefield definition SS_20.6mmR_100nm3mm.sdds

ELEGANT Output Files

The output results of "official" ELEGANT runs are in timestamped directories under /afs/slac/www/grp/ad/model/output/lcls2/elegant.


Modelled element and device data of LCLS-II are also available in SLAC's Oracle Database. See the Elements and Symbols tabs (they contain largely the same information).

Optics Plots

These are the Twiss parameter plots for each beampath. Click on an image for the set of plots of that beampath.

Superconducting linac related optics:

Gun B to SXR dump
Gun B to HXR dump
Gun B to BSY dump
Gun B through Diagnostics 0
Gun B to DASEL

Warm copper linac related optics:

Gun "A" to HXR dump
Gun "A" to SXR dump
Gun "A" to A-line


The following are descriptions of each electron beam traversal through the LCLS-II accelerator complex. These include both the paths relating to superconducting accelerating structures (those originating at gun "B") and the original warm copper related paths (those originating at the LCLS-I gun).

Beampath Table: Primary RF refers to the technology used for radio frequency structures of the primary acceleration of the beamline; "SC" = superconducting, "cu" = warm copper. Status refers to the administrative standing of the beampath. MAD filename prefix refers to the filenames of the MAD output relating to the beampath. The Beampath ID is the unique tag of the beampath understood by the MEME directory service. The maps are zoomable PDF. Middle-click to download, open with for instance Adobe Reader (zoom in with for instance View ↳Zoom ↳ Pan and Zoom). The maps show the all modelled elements of the LCLS-II mad deck, including devices (where the element has one), markers etc, with their suml and Z positions, arranged left to right by Z and hierarchically by modelled line. Arrows link the elements to show the path of the beam from element to element through the machine.
Primary RF Description Status MAD output filename prefix Beampath ID Elements / devices file Map Link
SC Gun B to SXR dump Under construction LCLS2scS SC_SXR
SC Gun B to HXR dump Under construction LCLS2scH SC_HXR LCLS2scH_lines.dat
SC Gun B to BSY dump Under construction LSCLS2scD SC_BSYD
- Gun B through Diagnostics line Under construction DIAG0 SC_DIAG0
cu Gun to HXR dump Repurposing present "LCLS-1" LCLS2cuH CU_HXR LCLS2cuH_lines.dat
cu Gun to SXR dump Proposal LCLS2cuS CU_SXR LCLS2cuS_lines.dat
cu Gun through A-line Connection to present "A-line" LCLS2cuA CU_ALINE LCLS2cuA_lines.dat

The mapping from elements to EPICS PV names (or at least the device name part of PV names) is defined by the file elementdevices_lcls2.dat. These lines files and maps were created using an awk script mad2dot.awk. mad2dot takes as input the print and survey files as output from Mad (see header of mad2dot), plus one or more "elementdevices" files. mad2dot creates a "lines" file for each beampath (for consumption by the directory service, so on-line apps know the device-line hierarchy), and a dot file, for instance, for each beampath. We then use the unix command dot, or Graphviz, to create a PDF from the dot file.

Publication Guide

For those people who need to change the lattice files, there is a README in CVS, in the same directory as the lattice files. That README describes how to do the CVS, and use a makefile to publish the output files to /afs/slac/www/grp/ad/model/output/.

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