1. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 1 Facilities Advisory Committee Meeting October 27, 2005 Project Status Drive Laser Change in the Gun design Launch System Design Transport tubes Installation Response to the April FAC recommendations Summary

2. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 2 Project Status The contract for the Drive Laser was awarded to Thales Lasers. Design review was held October 18 - 20 Construction of the S20 drive laser facility is underway. Old building has been demolished Requirements to the electrical and water systems were defined based on the Thales laser system requirements Design of the electrical system is near completion. Beneficial occupancy is planned for February 2006 The Laser safety system design is underway. The laser safety review planned at the end of November

3. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 3 Project Status The laser beam transport tubes were installed. Tubes passed the leak check Design of the optical tables completed. Procurement process started Design of the active beam steering stabilization system started. The system will be tested in Build. 407 Parts for the test were defined and ordered Optical Design of the Launch System for normal incidence completed The draft of the Drive laser Commissioning schedule is put together Schedule is being synchronized with the commissioning schedule for the gun

4. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 4 Project Status R&D effort is underway. LLNL completed modeling of the UV temporal pulse shaping. The UV conversion modeling code was completed and run on a number of cases. It was shown that to obtain efficient, temporally uniform UV pulses that we need to convert the IR beam to a spatial flat-top before frequency conversion. The temporal diagnostics designs were finished. For UV and blue measurements TG FROG was proposed. Orders were placed. ANL performed spatial shaping of broadband IR pulses using the Newport aspheric beam shaper. Optimum shaping conditions were defined. It was shown that extent of the bandwidth significantly affects the quality of shaping Work to arrange the collaboration with INFN and Elettra started

5. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 5 Thales Drive Laser System 1.5mx3.75m footprint (~4.5’x11.5’) Spectra Physics MILLENIA Vs Femtolasers Oscillator Femtosource Scientific 20s (chirped mirrors) JEDI #1 100 mJ,120 Hz JEDI #2 100 mJ,120 Hz Amplifier 2-pass Bowtie CompressorTHG Pre-Amp 4-pass Bowtie RGA Regen Amp StretcherDAZZLER 20 mJ, 120 Hz 80 mJ, 120 Hz 100 mJ, 120 Hz 119MHz 400mW 5W, 119MHZ 150ps 80mW 119MHz 1mJ, 120Hz >20mJ, 120Hz >40mJ, 120Hz >25mJ, 120Hz>2.5mJ, 120Hz To cathode Amplifiers are not cryo-cooled IR stability <1%rms (short term)

6. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 6 Thales Drive Laser System General Set-up

7. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 7 Cathode Launch System Design Grazing incidence vs. normal incidence Grazing incidence Advantages No in-vacuum mirror=> no wake Requires no space in gun-to-linac region Increased QE for P-polarization Disadvantages Requires grating to tilt the beam without introducing temporal slew and to produce round beam. Grating has less than 50% efficiency Large bandwidth with grating causes chromatic aberration Dispersed beam requires large optics (expensive!) Limited/complicated adjustment of beam size on cathode Low damage threshold of grating in UV

8. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 8 Cathode Launch System Design Grazing incidence vs. normal incidence Normal incidence Advantages Simple launch optics Launch optics allow continuous variation the beam size on the cathode Easy to preserve required temporal shape Disadvantages In-vacuum mirror causes transverse wake Lower QE Requires space in the gun-to-linac region In-vacuum mirror requires careful design

9. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 9 Normal vs Grazing Incidence Grazing incidence optics add risk to laser shaping Wakes from dual in-vacuum mirrors tolerable We have changed the design to normal incidence

10. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 10 Preliminary Gun Design for Normal Incidence Layout of Laser from Injection Mirror to Cathode laser injection cross vacuum valve cathode gun solenoid drawing compliments of R.F. Boyce & T. Osier

11. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 11 Optical Design of the Transport and Launch System System uses the aspheric beam shaper which transforms Gaussian beam into flat-top System allows continuous adjustment of the beam size on the photocathode Spatial Shaper and Zoom system for beam diameter adjustment are located in the laser bay upstairs Shaper output is imaged with adjustable magnification to the input of the relay system that images it to the photocathode through the transport tube

12. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 12 Layout Beam shaper UV converter Vacuum cell Zoom Transport tube Table in the tunnel Photocathode Virtual Cathode Steering system Active Steering Stabilization

13. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 13 Beam Profile on the Cathode ZEMAX Modeling

14. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 14 Beam Profile on the Cathode ZEMAX Modeling

15. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 15 Adjustment of the Beam Diameter

16. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 16 Beam Size on the vacuum mirror 10mm Radius on the cathode = 1.5mm Radius on the cathode = 0.6mm 10mm Size of the vacuum mirror – 14mm

17. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 17 Photocathode Launch System Optical system provides flat-top beam on the cathode System allows continuous adjustment of the beam radius on the photocathode from 0.6 to 1.5mm. Smaller (than 0.6mm) beam size can be achieved by using smaller aperture after the beam shaper Design avoids small beam size on optics, which could cause damage

18. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 18 Transport Tubes Installation

19. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 19 Transport Tubes Installation

20. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 20 Transport Tubes in the Vault

21. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 21 Response to the April FAC Recommendations Strengthening of the laser team The LCLS Laser Group leader– Bill White – started in May Long term staffing plan for the group has been developed One engineer was hired

22. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 22 Response to the April FAC Recommendations Coordination of the laser R&D activities Coordination of the efforts of LLNL and ANL is centralized in the LCLS Laser Group. As design elements are completed at LLNL and ANL, they are incorporated into the final design which is then reviewed by all interested parties. Purchase of the second laser The purchase of a second laser is not in the current baseline, but we hope to get it in the future Laser Bay has space and power for two lasers

23. Sasha GilevichFacilities Advisory Committee Gilevich@slac.stanford.edu October 27 2005 Injector Drive Laser Update 23 Summary First LCLS injector item – Laser transport tubes were installed Design of the gun has been changed to normal incidence. It significantly simplifies the optical set-up and the makes beam shaping less problematic Manufacturing of the Drive Laser and R&D work according to the schedule