LCLS-II Lattice Description

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:

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:

ELEGANT Output Files

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

Databases

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:

Warm copper linac related optics:

Beampaths

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
SC	Gun B to DASEL	Proposal	LCLS2scDA	SC_DASEL
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 LCLS2scH.dot, 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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