Sensitivity studies for the LCLS photoinjector beamline

The LCLS photoinjector beamline is now in the Design and Engineering stage. The fabrication and installation of this beamline is scheduled for the summer 2006. The photoinjector will deliver 10 ps long electron bunches of 1 nC with a normalized transverse emittance of less than 1 mm mrad for 80% of the slices constituting the core of the bunch at 150 MeV. Based on PARMELA simulations, stability requirements for all the physical parameters were derived. In this paper, we discuss the regulation requirements of the solenoid fields, accelerating fields and the phase stability of RF components. We also describe how specifications for the laser pulse were defined, in particular for the longitudinal and transverse uniformities. Finally, requirements for alignment of components and steering of the electron beam along the beamline are presented.