Injector Drive Laser Update

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					             Injector Drive Laser Update
        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
October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                1
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
                                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




October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                2
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
                                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

October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                3
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
                                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


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

       To                                              Amplifier              JEDI #2
                   THG         Compressor
     cathode                                           2-pass Bowtie       100 mJ,120 Hz
  >2.5mJ, 120Hz       >25mJ, 120Hz             >40mJ, 120Hz             100 mJ, 120 Hz


October 27 2005 Facilities Advisory Committee                        Sasha Gilevich
                                                  5
 Injector Drive Laser Update                              Gilevich@slac.stanford.edu
                   Thales Drive Laser System
General Set-up




October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                6
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
     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


October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                7
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
             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


October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                8
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
                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

October 27 2005 Facilities Advisory Committee                  Sasha Gilevich
                                                9
 Injector Drive Laser Update                        Gilevich@slac.stanford.edu
    Preliminary Gun Design for Normal Incidence
Layout of Laser from Injection Mirror to Cathode
                                                gun solenoid


       cathode
                                                             laser injection cross

                                                       vacuum valve




                                                      drawing compliments of R.F. Boyce & T. Osier
October 27 2005 Facilities Advisory Committee                       Sasha Gilevich
                                                 10
 Injector Drive Laser Update                             Gilevich@slac.stanford.edu
      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

October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                11
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                    Vacuum
                                        Layout
                      cell                           Zoom
  Beam shaper
  UV converter


                            Virtual                             Transport
         Table in          Cathode                                tube
            the                                 Steering
          tunnel                                system




  Photocathode

                                                                                       Active
                                                                                     Steering
                                                                                    Stabilization




October 27 2005 Facilities Advisory Committee                     Sasha Gilevich
                                                12
 Injector Drive Laser Update                           Gilevich@slac.stanford.edu
                    Beam Profile on the Cathode
                                    ZEMAX Modeling




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




October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                14
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
           Adjustment of the Beam Diameter




October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                15
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
            Beam Size on the vacuum mirror
   10mm




                                                     10mm
  Radius on the cathode =                                   Radius on the cathode =
          1.5mm                                                     0.6mm
                                                                    Size of the vacuum mirror – 14mm

October 27 2005 Facilities Advisory Committee                           Sasha Gilevich
                                                16
 Injector Drive Laser Update                                 Gilevich@slac.stanford.edu
               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
October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                17
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                 Transport Tubes Installation




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




October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                19
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                 Transport Tubes in the Vault




October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                20
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                   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

October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                21
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                   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


October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                22
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu
                                     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

October 27 2005 Facilities Advisory Committee                   Sasha Gilevich
                                                23
 Injector Drive Laser Update                         Gilevich@slac.stanford.edu

				
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