1 Enhancements to the Linac Coherent Light Source

2 LCLS Strategic Plan Near term - 2 years “LCLS-I” Increase user capacity flexible beam delivery through optics, linac energy and pulse length changes fixed gap afterburner at second harmonic 16 keV Intermediate term – 5 years “LCLS-II” Same injector, last 1/3 of linac, same conventional facilities Implement full capacity: simultaneous use of 6 hutches Increase spectral capability: present 800eV - 8keV, future 500eV - 24keV Implement polarization control Implement seeding Long term – 10 years “LCLS-III” Expansion: additional injectors, linac sections, undulators, conventional facilities higher rep. rate, linac energy, pulse properties, number of stations

3 LCLS upgrade – “LCLS-II” Increased energy rangetoward transform limited pulses

Å 4-14 GeV FEE-1 Existing 112-m Undulator ( Å) 0.75 Å adjustable gap SHAB 30 m Shortened 74-m Undulator 5 m FEE-2 SXR2 (40 m) 5 m full polarization control self-seeding option 6-60 Å adjust. gap 6-60 Å adjust. gap SXR1 (40 m) 4-GeV bypass new adj. gap und. ( Å) 4-GeV SXR and 14-GeV HXR simultaneous op’s with bypass line 2-pulse 2-color No civil construction. Uses existing beam energy and quality. full polarization control Existing Phase-1 Phase-2Phase-3 self-seeding HXR option (2 bunches) EEHG*? 240 nm  6 nm LCLS-II: 3 Phases over 5 years * Phys. Rev. Lett. 102, (2009) 5 m full polarization control

5 Phase-1 (2 nd Harmonic Afterburner) Existing Å capabilities fully preserved Quick path to 2nd harmonic (0.75 Å) with afterburner (1-2 GW) Full polarization control of 1 st or 2 nd harmonic Phase-2 (Soft X-ray Line) Two-pulse, two-color, variable delay (0-50 ps) soft X-rays (6-60 Å) Self-seeding option (6-60 Å) for narrow bandwidth (10  4 ) Full polarization control in both SASE and self-seeded modes Bypass line allows simultaneous 4-GeV & 14-GeV op’s (60 Hz/ea) Possible Echo-Enhanced seeding at 240  6 nm (or shorter?) Phase-3 (Ultra-Hard X-ray Line) Existing 1.5-Å to 15-Å & 2 nd harm. op’s fully preserved 0.5 Å (up to 15 Å) by replacing all existing undulators with variable gap Full polarization control at any HXR wavelength Self-seeding HXR option with two e  bunches (~10 ns spacing) Summary of three Phases

6 Undulator Parameters Periods, gaps and peak fields for new LCLS undulators are well within state-of-the-art for hybrid permanent magnet devices Soft XR Hard XR ~ 2 x ~ 4 x

7 Timeline compatible with operation FY10FY11FY13FY12FY14FY15 Annual 2 month summer downtime Phase 1 Installation Phase 2 Installation Phase 3 Installation Startup ED&I Fabrication

8 Limitations of SLAC Linac The SLAC Linac has been in nearly continuous use since May The major components of the Linac are: –Klystrons (240) Now 60,000 hr lifetime, replaced as needed, SLAC rebuilds klystrons (50%) and constructs new ones (50%). –Pulsed modulators (240) Major upgrades with SLC in 1980s, new upgrades underway for LCLS: power feeds, modulator controls, safety systems. –RF controls Major upgrades with SLC in 1980s, new upgrades underway for LCLS: phase, amplitude, and stability controls and electronics. –“Three meter” RF copper accelerating structures (960) No new ones since 1966, none have failed in every day use. Expected minimum lifetime from now of >20 years without erosion mitigation. Metallographic tests done on one unit in service for 31 years. Showed only water cooling line erosion. Vacuum and RF characteristics are fine. Mitigation studies started.

9 Up to 6 more undulator branch lines possible at ±1, ±2, and/or ±4 deg. Existing 3-km SLAC linac can supply 3 different simultaneous 14-GeV, 120-Hz beams or 28-GeV & 14-GeV beams (shared with PEPX). Can also operate in multi-bunch (~10, 10ns apart) mode to feed FEL farm. Injector Test Facility will be used to develop source technology, do critical beam physics, and also becomes the electron source for LCLS upgrades. Limitation of present LCLS Facilities HXR SXR 4º4º4º4º 2º2º2º2º 1º1º1º1º 0º0º0º0º 0º0º0º0º 1º1º1º1º 2º2º2º2º 4º4º4º4º Future FEL Lines Injector Test Facility Possible CW, SC-linac, or compact, high rep-rate X-band linac on SLAC site to feed FEL farm. Longer-Term