E. Bong, SLACLCLS FAC Meeting - April 29, 2004 Linac Overview E. Bong LCLS FAC Meeting April 29, 2004 LCLS
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 COST Report – WBS3 x Fund
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 COST Report – WBS3 x Fund
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac Milestones Data from LCLS Project Manpower Loaded Schedule
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 Nominal System Design 1.5-Å SASE FEL Linac: Requirements Acceleration to 14.3 GeV (4.5 GeV min.) Bunch compression to 3.4 kA ( x,y 1.2 m) Emittance preservation (<20% ‘slice’, <100% ‘projected’) Final energy spread (<0.02% ‘slice’, <0.1% ‘projected’) Minimal sensitivity to system ‘jitter’ Diagnostics integrated into design Flexible operations (1.5 to 15 Å, low-charge, chirp, etc.) Compatibility with other SLAC programs use 2 compressors, 3 linacs
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 Nominal LCLS Linac Parameters for 1.5-Å FEL Single bunch, 1-nC charge, 1.2- m slice emittance, 120-Hz repetition rate… (RF phase: rf = 0 is at accelerating crest) SLAC linac tunnel research yard Linac-1 L 9 m rf 25° Linac-2 L 330 m rf 41° Linac-3 L 550 m rf 10° BC-1 L 6 m R 56 39 mm BC-2 L 22 m R 56 25 mm LTU L =275 m R 56 0 DL-1 L 12 m R 56 0 undulator L =130 m 135 MeV z 0.83 mm 0.10 % 250 MeV z 0.19 mm 1.6 % 4.54 GeV z mm 0.71 % 14.1 GeV z mm 0.01 % SLAC linac LCLS INJ 21-1b21-1d X Linac-X L =0.6 m rf = 21-3b24-6d25-1a30-8c
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac L1 Subsystem Linac Sector 21-1 Accelerates a single 1-nC, 10-ps long electron bunch, at a repetition rate of 120 Hz, from 135 MeV to 250 MeV. Introduces energy chirp to allow bunch compression in BC1. X-Band linearizes energy spread.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac BC1 Subsystem Linac Sector 21-2a to 21-3a Compresses a single 1-nC, 830- m long (rms) electron bunch, at a repetition rate of 120 Hz, at 250 MeV to an rms length of 190 m.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac L2 Subsystem Linac Sector 21-3b to 24-6d. Largely unmodified SLAC Linac. Accelerates a single 1-nC, 0.2-mm long electron bunch, at a repetition rate of 120 Hz, from 250 MeV to 4.5 GeV. Energy chirps the bunch to allow compression in BC2.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac BC2 Subsystem Linac Sector 24-7a to 24-8d. compress a single 1-nC, 195- m long (rms) electron bunch, at a repetition rate of 120 Hz, at 4.54 GeV to an rms length of 22 m
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac L3 Subsystem Linac Sector 25 to 30. Largely unmodified SLAC Linac.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac L3 Subsystem Linac Sector 25 to 30. Largely unmodified SLAC Linac. Accelerates a single 1-nC, 0.02-mm long electron bunch, at a repetition rate of 120 Hz, from 4.5 GeV to 14.3 GeV.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac LTU Subsystem Schematic
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac LTU Subsystem New Beamline extending from FFTB muon plug wall in SLAC BSY, across research yard in new housing to FEL undulator. Transports a 1-nC, 20- m long (rms) electron bunch, at a repetition rate of 120 Hz, at 14 GeV to the LCLS FEL undulator. Includes energy and emittance diagnostics, energy collimation, bunch length diagnostics and undulator launch feedback.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac E-Dump Subsystem New Beamline located between exit of Undulator and Near Experimental Hall in new underground housing. Separates electron beam from X-Ray FEL beam directs beam to dump. Includes energy and energy spread measurement capability to 10 -4
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac X-Band Subsystem X-Band located in L1 just up-stream of BC1 bunch compressor. Linearizes energy gradient prior to bunch compression to minimize CSR instability. 1 x XL-4 klystron feeding 1 NLC- type accelerating structure. Parameter LCLS (Nom) NLCTA (Nom) Units Structure Length60 cm Structure Voltage1930MV Phase-160-deg Klystron Power2150MW Repetition Rate12060Hz Duty Cycle ss
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac Challenges RF Stability (See R. Akre talk) Existing system phase and amplitude stable to requirements over several seconds. Require bunch length and energy feedback to meet requirements over longer time scales. Bunch Length Measurement & Feedback (See P. Krejcik talk) Bunch length measurement in R&D at SPPS. Epics/SLAC Controls System Compatibility (See Controls breakout talks) Require Epics system to access SLC control system in order to operate existing equipment required for LCLS. SLC control system needs to access EPICS system to operate LCLS upgraded equipment required in high power beam operations. Articulated Bunch Compressors (See P. Emma talk) Articulation required for R 56 tuning for full range of beam charge. Simplification of LUTL bend chamber design to reduce design challenge. BPM Module Design (See P. Krejcik talk) Measurement of full range of beam charge required. Two beam e + e - beam operations place additional challenge on module design.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS/SLAC Program Compatibility Program Changeover Time 15 minutes from LCLS to damped SLAC beam. 24 hours from LCLS to undamped ESA beam. Moving Chicanes Articulates collinear with linac axis for straight-ahead. X-Band Structure Aperture 7mm, smaller than linac scrapers (16.5mm) Smaller than undamped beam. Moves off-axis, temporary pipe installed. BPM Module Design Charge Range. LCLS 0.2nC to 1nC. ESA ??? Two Beam e - e + Running.
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 Multiple Undulator Expansion
E. Bong, SLACLCLS FAC Meeting - April 29, 2004 LCLS Linac System Summary Layout and initial design of system underway. Expertise on site for design and execution of modifications to existing SLAC Linac and construction of new beamlines. Simplification of LEUTL chicane and experience with SPPS chicane to be applied to LCLS Chicane. BPM module design challenging. RF stability looks achievable. Bunch length measurement required for RF feedback in R&D phase.