Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 LCLS Project Overview What is the LCLS ? Transition from 3 rd generation light sources to x- ray free-electron lasers The SASE principle and linac-driven free-electron lasers Performance Accomplishments R&D and construction plan

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Single pass Free-Electron Lasers Uses SLAC Linac Å (0.5-5 Å in 3rd harmonic) Peak brightness 10 orders of magnitude above Advanced Photon Source (APS) Time averaged brightness 2-4 orders of magnitude above APS Sub-picosecond pulses Fully transversely coherent radiation Design and R&D studies, a ANL-BNL-LANL-LLNL-SLAC- UCLA collaboration The X-ray FEL is a powerful tool to explore matter and fundamental physics. What is the LCLS ?

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 The transition from 3 rd generation light sources to x-ray free-electron lasers FELs

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 The SASE principle and linac- driven free-electron lasers Main components of a SASE FEL –A bright electron source (photo-injector) –A bunch compression system –A linear accelerator –An undulator –The photon beamlines –The experimental areas

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 LCLS layout

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 SASE FEL theory well developed and verified by simulations and experiments FEL radiation starts from noise in spontaneous radiation Transverse radiation electric field modulates the energy and bunches the electrons within an optical wavelength Exponential build-up of radiation along undulator length SASE FELs Undulator Regime Exponential Gain Regime Saturation 0.2 fs 0.9 fs 1 % of X-Ray Pulse Electron Bunch Micro-Bunching

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Wavelength 1.5 Å (range Å, 1st harm) Electron energy GeV (range ) Bunch length 230 fsec (full) coherent photons/pulse Undulator length120 m Undulator gap6 mm Saturation peak power 9 GW Peak brightness Average brightness Main parameters

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Light source performance chart Peak and time averaged brightness of the LCLS and other facilities, operating or planned AveragePeak

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Other FEL based light sources are being tested, built or planned The TESLA Test Facility (TTF) at DESY –Lasing with gain ~3000 observed at nm X-ray FEL TESLA at DESY (associated with the linear collider project) –CDR being written Source Development Laboratory (SDL) at BNL-NSLS –Electron beam testing Harmonic Generation (HGHG) experiment successful at BNL-ATF VISA experiment at BNL-ATF –Study the FEL radiation with beam characteristics and tolerances close to those of the LCLS FELs under study in Japan, Italy, England and Germany (BESSY II) LEUTL at ANL-APS –First observation of saturation

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 FEL experiment A crucial milestone in FEL physics was reached when the LEUTL experiment measured large amplification and evidence of saturation last summer at 530 and 385 nm

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , D particle tracking through LCLS accelerator 150 MeV 250 MeV 4.54 GeV 14.3 GeV Energy deviation along electron bunch Transverse cross section of electron beam

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 How to achieve a short bunch The simulation tool was used to optimize the electron beam in 6-dimensional phase space –Preservation of transverse electron brightness leads to shorter undulator and more relaxed tolerances –Mechanism for achieving short electron bunches (230 fs) confirmed by the simulations –Even shorter bunches can compromise transverse electron brightness 230 fs bunch length is the result of optimization in all 6 dimensions

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 X-ray optics transport simulations 0150 GINGER output: Tables of electric field values at undulator exit at different times Time Domain Frequency Domain Temporal Transform Spatial Transform Transverse position, microns x watts c m 2 Power Density x watts c m Time, femtoseconds 42 Power Density 0 w0w0 w /fs 1.73 x watts c m 2 w /fs frequency Power Density Wavenumber, mm -1 x watts c m 2 Power Density viewer Viewer Transformation to Frequency Domain Propagation to arbitrary z R, mm

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 FFTB hall for undulator and diagnostics LCLS Undulator Hall and Experimental Area Layout Hall A: Atomic Physics Warm Dense Matter X-Ray Physics Hall B: Nanoscale Dynamics Femtochemistry Biological Imaging

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Conceptual Design Report Conceptual Design Report is on schedule First draft contributions are being reviewed Goal is to have it ready, in draft form, by early summer 2001

Max Cornacchia, SLAC LCLS Project Overview BESAC, Feb , 2001 Summary Substantial progress made in most areas Experimental confirmation of the photo-injector brightness is the most important short term goal –Program is receiving strong support from SLAC Integration photo-injector/FEL physics/x-ray optics to continue –Realistic x-ray FEL characteristics, tolerances, match to the experiments X-ray optics to address detailed requirements of the “first experiments” Focus on CDR for the next 6-8 months Preparation for Lehman Review