Drive Laser Commissioning Status Reminder of requirements on Drive Laser Thales laser Transport system Commissioning in three areas Thales laser and it’s specs Beam conditioning and transport Virtual cathode alignment Lessons learned – remaining issues Future

UV pulse goals IR to UV conversion efficiency > 10 %, 2.5 mJ output @ 255 nm 252-258 nm, < 2% energy stability 120 Hz, MTBF > 5000 hours Spatial Profile FWHM = 1.2 – 3.0 mm Temporal Profile FWHM = 10 ps (5-20 ps) 90-10 rise and fall times < 1 ps flat-top, < 8% peak-to peak

Thales Laser system Stretcher UV Conversion Dazzler Preamplifier Compressor Oscillator Final Amplifier Regen

Active Steering Stabilization Transport Beam shaper Vacuum cell Zoom Transport tube Table in the tunnel Photocathode Virtual Cathode Steering system Active Steering Stabilization L1 L2 L3 L4 L5 L6 Waveplate Polarizer Powermeter Camera Shutter Laser Bay Launch System

Active Steering Stabilization M6 In order to meet centroid position stability requirement (min 60μm) M6 should be stabilized with 35μrad accuracy Sensitivity of the mirror mount 7arcsec – 34 μrad Laser Bay Transport Tube M4 Table in the tunnel Camera C2 M5 From Virtual Cathode M3 Camera C1 Steering Stabilization system test is underway M2 To Photocathode

Transport System in the Laser Bay Remotely Controlled Mirror Lens Shaper Beam Size Adjustment Shaper Input Adjustment To Transport tube Laser Output

Optical System next to the Photocathode From Transport tube Steering Stabilization Camera Remotely Controlled Mirror Lens Virtual Cathode camera Steering Stabilization Camera Lead Block Lens Remotely Controlled Mirrors Powermeter Lead Blocks Photocathode In vacuum mirror

Transport Commissioning Shaper Diagnostics Characterization Calibration of diagnostics GTL Installation Virtual Cathode

Timeline - Laser Commissioning Laser table and LSS in Vault Feb 13th – Began taking UV into vault Feb 23 – GTL installation began VC March 1 to March 12. Gun Installation began March 12. ARR April 4 Beam April 5

Commissioning Issues Better Schedule coordination Too many people all working in small space Minor problems have widespread impact Because of shortened laser commissioning, some laser commissioning will continue with injector commissioning

Commissioning Issues Streak Camera Cross correlator

Temporal Pulse Shaping The achieved temporal pulse shape meets physics requirements for the injector commissioning Plan to improve the temporal shape Replace the Lyot filter in the regen amplifier by the edge mirrors – this will reduce oscillations Continue working on the Dazzler settings and the optimum UV conversion crystals lengths Thales engineers are coming back in September to continue working on shaping Plan B – to use stacking of Gaussian pulses Design and parts for pulse stacking are in place

Commissioning Issues Newport aspheric telescope GBS-UV H Converts Gaussian to flat-top Requires good Gaussian input Very sensitive to alignment Aperture is just as good and much simpler to align Allows flexibility Simplifies overall transport GBS-UV H

Today

Commissioning Issues Transport Tubes 10m long Hydro-carbons coating and damaging inside of windows when exposed to UV Dust inside tube settling on inside of windows – Damage and diffraction Will go to less expensive windows and on site pump so the windows can be replaced more quickly.

Commissioning Issues Oscillator Problems Picomotor translation stage instability Femtolase will replace Coarse control currently disabled/manual Phase ambiguity due to locking at 476MHz Impacts phasing of RF This oscillator does not self start mode-locking or RF locking Femtolase will replace this oscillator with an all new unit that should address all of these issues

Jedi Pump Laser Failure of Q-switch driver Various chiller problems We diagnosed. Thales rushed a board and technician to us. 3 Days lost Various chiller problems Now have local source of spares Began purchasing spares in November CR Delayed order placement Should receive in August Hot swappable spares

Future - Hand Over to Ops Now Develop procedures for laser Automate things that can and need to be automated August 07 Down Train Operations Group on typical Operation Procedures Hand off laser by Jan 08 Laser Group will support Ops Scheduled Maintenance Issues that arise outside of the typical operation envelope

End