LCLS Conceptual Design Report - Stanford Synchrotron Radiation ...

L C L S C O N C E P T U A L D E S I G N R E P O R T
The LCLS
(Linac Coherent Light Source)
Photon
Beam Lines
Linac 3
Linac 2
Linac 1
3 km
Undulator
B Factory Rings
Linac 0
Figure 2.1 Layout of the Linac Coherent Light Source.
RF Gun
Bunch Compressor 2
2 km
Bunch Compressor 1
Existing Linac
A new injector consisting of a gun and a short linac is used to inject an electron beam into the
last kilometer of the SLAC linac. With the addition of two stages of magnetic bunch
compression, the beam at the entrance to the undulator has an energy of 14.3 GeV, a peak current
of 3,400 A, and a normalized emittance of 1.2 mm-mrad. A transfer line takes the beam and
matches it to the entrance of the undulator. The 121-m long undulator will be installed in the
tunnel that presently houses the Final Focus Test Beam Facility. After exiting the undulator, the
electron beam is deflected onto a beam dump, while the photon beam enters the experimental
areas.
The experimental areas are housed in two halls. The first hall, located just after the beam
dump in the SLAC Research Yard, is a 30m × 55 m structure, which will contain two x-ray
hutches for characterization of the beam and subsequently for experiments. The x-ray beam will
pass through the Near Hall into a 227 m tunnel to the Far Hall, a 57 m × 33 m structure with
experiment facilities below grade and office/lab space on grade. This building will also include
two x-ray hutches at the completion of the project.
2.13 Performance Characteristics
Figure 2.2 shows the peak and average brightness as a function of photon energy. The LCLS
is designed to be tunable in the photon wavelength range 1.5 – 15 Å, corresponding to 4.5 –14.3
GeV electron energy.
2-14 ♦ O V E R V I E W
1-98
8360A1