Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Simulations of LSC in the LCLS Injector Cécile Limborg-Déprey, P. Emma, Z. Huang, Juhao Wu March 1st, 2003 LSC in drifts Simulations for Injector  Case of 100  m modulation  Other wavelengths [ 50,150,200, 300]  m Conclusion LSC in drifts Simulations for Injector  Case of 100  m modulation  Other wavelengths [ 50,150,200, 300]  m Conclusion

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Simulations of LSC in drifts Simulations description 40k/200k particles Distribution generated using the Halton sequence of numbers Longitudinal distribution 2.65 m of drift With 3 cases studied 6MeV, 1nC 6 MeV, 2nC 12 MeV, 1nC Simulations description 40k/200k particles Distribution generated using the Halton sequence of numbers Longitudinal distribution 2.65 m of drift With 3 cases studied 6MeV, 1nC 6 MeV, 2nC 12 MeV, 1nC +/- 5%

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Summary 100  m Comparison with theory Transverse beam size evolution along beamline taken into account (Radial variation of green’s function for 2D ) Evolution of peak current NOT taken into account yet Absence of dip in 6MeV curve : “Coasting beam “ against “bunched beam” with edge effects Intrinsic energy spread

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Nominal Tuning 10 ps pulse (rise/fall time 1ps ) 1 nC Nominal Tuning 10 ps pulse (rise/fall time 1ps ) 1 nC Laser + Gun Linac0-1 Linac0-2 6MeV0MeV60MeV150MeV ASTRA Simulations of LSC along Injector Beamline

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC ASTRA Simulations for modulation of 100  m Modulation Wavelength = 100  m, with  8% amplitude peak-to-peak “Noise of  8% amplitude around flat top is likely to be present “ P.Bolton FWHM = 3mm Longitudinal bining = 200 points (~ more than 6 bins per period) 1 Million particles Modulation Wavelength = 100  m, with  8% amplitude peak-to-peak “Noise of  8% amplitude around flat top is likely to be present “ P.Bolton FWHM = 3mm Longitudinal bining = 200 points (~ more than 6 bins per period) 1 Million particles Current density with modulation = 100  m Region of interest Fourier Analysis Position (mm) Cycles per mm

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Longitudinal Phase Space After removal of correlation up to order 5 Energy Current Fourier transform Fit up to 3 rd order Substract and Fit Amplitude + rms w.r.t reference level z = 0.15 m E = 6MeV Gun Exit   E = 0 → 0.35 keV  Current modulation = 5.65% → 3%

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Energy Current Fourier transform z = 1.4 m E = 6MeV Entrance L01   E = 0.35 keV → 1 keV  Current modulation = 3% → 1.5%

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Exit L01 Energy Current Fourier transform z = 4.4 m E = 60MeV Exit L01   E = 1 keV → 3 keV  Current modulation = 1.5 % → 1.5%

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Exit L02 Energy Current Fourier transform z = 8.4 m E = 150MeV Exit L02   E = 3 keV → 3.9 keV  Current modulation = 1.5 % → 1.6%

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Summary 100  m

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Summary 50,100,150,300  m Attenuation by factor More than 5 for  <100  m ~ 5 for  >100  m

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC At end LCLS injector beamline:  Current density modulation strongly attenuated  residual energy oscillation has amplitude between 2 keV and 4 keV for wavelengths [50  m, 500  m]  Impedance defined by At end LCLS injector beamline:  Current density modulation strongly attenuated  residual energy oscillation has amplitude between 2 keV and 4 keV for wavelengths [50  m, 500  m]  Impedance defined by Same results with PARMELA

Injector Requirements Linac Coherent Light Source Stanford Linear Accelerator Center Technical Review, March 1st, 2004 Cécile Limborg-Déprey, SLAC Conclusion Good agreement Simulations / Theory for drift and Acceleration Solutions to handle Numerical Problems Noise Problem ( high number of particles) Shorter wavelengths (new option in ASTRA) Clear “Attenuation” in gun makes situation less critical than first thought But not enough attenuation : for wavelengths >100  m : attenuation line density modulation by factor of~5 for wavelengths <100  m : attenuation line density modulation by factor of more than 5 To reach less than 0.1% at end of beamline requires less than 0.4% rms on laser so +/- 0.56% = far beyond what is achievable by laser Also large energy modulation in all cases (“large” = of the order or more than intrinsic energy spread) Heater is required as microstructure present in all wavelengths cases and in particular those < 100  m Good agreement Simulations / Theory for drift and Acceleration Solutions to handle Numerical Problems Noise Problem ( high number of particles) Shorter wavelengths (new option in ASTRA) Clear “Attenuation” in gun makes situation less critical than first thought But not enough attenuation : for wavelengths >100  m : attenuation line density modulation by factor of~5 for wavelengths <100  m : attenuation line density modulation by factor of more than 5 To reach less than 0.1% at end of beamline requires less than 0.4% rms on laser so +/- 0.56% = far beyond what is achievable by laser Also large energy modulation in all cases (“large” = of the order or more than intrinsic energy spread) Heater is required as microstructure present in all wavelengths cases and in particular those < 100  m