| Paper | Title | Page |
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| MOPKF079 | The Linac Coherent Light Source Photo-Injector Overview and Some Design Details | 500 |
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The Linac Coherent Light Source (LCLS)[*] is a SASE free electron laser using the last 1/3 of the SLAC two mile linac to produce 1.5 to 15 angstrom x-rays in a 100 meter long undulator. A new 135 MeV photo-injector will be built in an existing, off-axis vault at the 2/3 point of the main linac. The injector accelerator consists of a BNL/SLAC/UCLA s-band gun followed by two 3-meter long SLAC accelerator sections. The 5.6 MeV beam from the gun is matched into the first accelerator section and accelerated to 135 MeV before injection onto the main linac axis with a 35 degree bend [**]. Several modifications have been made to the rf gun, linac and beamline as well as the inclusion of several diagnostics have been incorporated into the injector design to achieve the required 1.2 micron projected emittance at a charge of 1 nC. In addition, a laser heater [***], will increase the uncorrelated energy spread to suppress coherent synchrotron radiation and longitudinal space charge instabilities in the main accelerator and bunch compressors [****]. The configuration and function of the major injector components will be described.
* Linac Coherent Light Source (LCLS) CDR No. SLAC-R-593 UC-414, 2002 ** C. Limborg et al., Proc. of the 2003 International FEL Conf *** R. Carr et al, Contrib. to these proceedings **** Z. Huang et al., Contrib. to these proceedings |
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| MOPKF083 | Inverse Free Electron Laser Heater for the LCLS | 512 |
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| The LCLS Free Electron Laser employs an RF photocathode gun that yields a 1 nC charge bunch a few picoseconds long, which must be further compressed to yield the high current required for SASE gain. The very cold electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. We propose to do this by interacting an infrared laser beam with the electron bunch in an undulator added to the LCLS gun-to-linac injector. The undulator is placed in a 4-bend chicane to allow the IR laser beam to propagate co-linearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun laser. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the implementation of the laser heater |