LCLS Injector: Introduction D. H LCLS Injector: Introduction D. H. Dowell, SLAC Injector RF Review: November 3, 2004 Injector Performance Requirements Injector Description The LCLS Injector Facility at Sector 20 Detail of Gun to Linac Region Gun and Solenoid Description Injector RF Design Status & Schedule Charge to this Committee

LCLS Injector Performance Requirements:

LCLS Injector Configuration SLAC Main Linac Beamline Transverse RF Cavity Laser Heater & Chicane 35o Bend Straight Ahead Spectrometer L0-1 & L0-2 3-m SLAC Sections Electro-Optic Diagnostic OTR Emittance Diagnostics Radiation Shield Walls RF Gun & Solenoid Load Lock Gun Diagnostics

UV Launch and Condition. Sector 20 Sector 20 Alcove Laser Bay Drive Laser Drive Laser System Transport Tubes Transport Tube Laser Heater RF Gun Laser Heater UV Launch and Condition. Photocathode Gun & Launch System Electron Diagnostic

S20 Alcove Floor Plan Title I Completed Laser Penetration Title I Completed Title II Specifications Released Room & Utilities Sized for 2 Drive Lasers

High Power RF for LCLS Injector Walls of re-built S20 Alcove No procurement of high power RF, except waveguide Waveguide runs established and in design LLRF System in design

Gun to Linac Region Cathode Load Lock RF Gun Gun Solenoid Gun Spectrometer Linac Solenoid L0-1 Porcupine Cathode Clamp

Dual Feed RF Gun and Solenoid Dual Feed/Racetrack Design Corrects RF Fields to Second Order Solenoid Design Includes Both Dipole and Quadrupole Field Correctors

Gun Solenoid will have Dipole and Quadrupole Correction Coils Measurements of Gun Solenoid Multipole Fields Gun Solenoid will have Dipole and Quadrupole Correction Coils Solenoid being designed with both dipole and quadrupole correcting coils

Injector RF Design Status L0-1 Accelerator section Dual feed RF design complete Engineering design nearly complete Subject of this review 120 Hz Gun Solenoid design complete, Drawings released RF design nearly complete Redesigned coupler holes solved pulsed heating problem Adopted racetrack geometry for full cell Issued RFI and held technical meetings with prospective vendors Unresolved issues & Topics of this review: Decide on 0-pi mode separation Final design for bulk cooling system Load lock deferred, SBIR proposal for funding

LCLS Project Schedule

LCLS Injector and Linac Schedule Gun and L0-1 needed for installation: October 2006

Charge to the Committee Critically assess the RF, thermal and mechanical designs for the gun and first accelerator section (L0-1) which are proposed to meet the LCLS injector requirements The Committee is asked to provide comments and recommendations on: Beam dynamics and the dual feed and racetrack designs for the gun and L0-1 accelerator section. The elimination of dipole and quadrupole field distortions with dual feed couplers and racetrack shaped coupler cells. Thermal management and RF mode issues for the gun. Thermal distortion of the gun when operated at 120 Hz & 120 MV/m. Excitation of the 0-mode and its effect in the gun during the RF transient. Whether or not the 0-pi mode separation should be increased. Manufacturing, RF testing and tuning procedures. The Committee is requested to respond to the following general issues: 1. Identify and quantify technical issues related to the Injector RF design 2. Determine if the design will meet LCLS requirements 3. Identify any technical issues not already included in design 4. Determine if design, RF tuning and construction plans are reasonable 5. Make comments and suggestions for improving the RF design A written report of the committee’s comments and recommendations is requested.