Last modified: Tue Mar 28 13:05:04 PDT 2017
SLAC National Accelerator Laboratory LCLS Lattice Description
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This is the home page of the lattice descriptions of the Linac Coherent Light Source (LCLS) Accelerator. The lattice descriptions are expressed in the Methodical Accelerator Design (MAD) language (version 8). There is a similar page for the planned LCLS II accelerator.

This page superceeds the LCLS Beamline Design Optics "sharepoint" site, which itself superceded the original LCLS Beamline Design Optics Files. Those pages are still up, but should be considered archived.

Lattice Description Files

The following are the LCLS lattice description files in SLAC's CVS, as input to MAD:

Main command file LCLS_main.mad8
Matching command file LCLS_match.mad8
Linac 1 definitions LCLS_L1.xsif
Linac 1 for Elegant LCLS_L1e.xsif
Linac 2 definitions LCLS_L2.xsif
Linac 2 for Elegant LCLS_L2e.xsif
Linac 3 definitions LCLS_L3.xsif
Linac 3 for Elegant LCLS_L3e.xsif
A-line definitions ALINE.xsif

Lattice Output Files

The output results of "official" MAD runs are in timestamped directories under /afs/slac/www/grp/ad/model/output/lcls. The latest output is always in /afs/slac/www/grp/ad/model/output/lcls/latest


Modelled element and device data are 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 resulting from the latest deck, for each beampath. Click on an image for the set of plots of that beampath.

LCLS gun to main dump
LCLS gun spectrometer
LCLS 135 MeV spectrometer


The following are descriptions of each electron beam traversal through the "LCLS" accelerator complex. In the context of the LCLS-II project now under construction, these represent the CU related beampaths of the future. The paths described here, are as they are now.

Beampath Table: Primary RF refers to the technology used for radio frequency structures of the primary acceleration of the beamline; "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 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 Lines file file Map Link
cu Gun to HXR dump In Operation LCLS CU_HXR LCLS_lines.dat
cu Gun to 135MeV Spectrometer In Operation SPEC CU_SPEC SPEC_lines.dat
cu Gun to Gun Spectrometer In Operation GSPEC CU_GSPEC GSPEC_lines.dat
cu Gun to A-line In Operation LCLSA CU_ALINE LCLSA_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.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 element/devices files - the main one being elementdevices.dat. mad2dot creates the lines file (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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