Drive Laser Facility Layout Drive Laser Architecture Technical Issues Injector Drive Laser Overview Sasha Gilevich, SLAC Lehman Review August 11, 2004 UV Specifications Drive Laser Facility Layout Drive Laser Architecture Technical Issues Summary 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

UV Beam Specifications at Photocathode Parameter Nominal spec Tolerance wavelength 255nm nom. Longer wavelength requires higher energy +/- 3nm pulse energy > 0.20 mJ (for 1 nC production with 3x10-5 QE) < 2 % rms variation fluence profile Uniform (nom.) (adjustable) < 10 % (peak-to-peak) spot radius 1.2 mm < 4 % (shot-to-shot) Centroid pos. < 10 % radius (RMS over multiple shots) rep rate 120 Hz (10 to 120Hz) power profile Uniform (adjustable plateau slope – 10% to +20%) < 5% (RMS noise on the plateau) profile FWHM 10 psec adjustable from 5 to 20 psec < 2 % (RMS over multiple shots) Rise/fall times 1.0 psec (10% - 90%) timing jitter (with respect to RF) < 0.5 psec (shot-to-shot) 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

UV Launch and Condition. Sector 20 Laser Laser Bay Drive Laser Transport Tube 10 m Laser Heater Accelerators RF Gun UV Launch and Condition. 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Layout of Laser Room at S20 Space & Utilities for 2 Drive Lasers 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Drive Laser Room Specifications Laser Room Requirements: Class 100,000 clean room Positive air pressure Relative humidity 50% (+/-2%) Temperature 20 to 22 deg C set point range (+/-0.5 deg C regulation) Hepa filters Two dimmer light switches with remote control Floor: Clean room tile or epoxy paint Walls: Epoxy paint Grounded cable trays and optical tables Ceiling Height: 10 feet Ceiling Material: Clean room grade tiles sealed with gaskets. 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Drive Laser Structure Drive Laser will be a fully purchased and integrated system Optical transport, launch system, and diagnostics to be built by SLAC Several laser companies showed interest and capability to build the system Dazzler 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Steering Stabilization UV Launch System Steering Stabilization Flattener Spatial Shaper Launch Grating Cathode Window Cathode Window Telescope lenses Telescope lenses Grating and Trimmer 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Major Drive Laser Issues Stability of the final amplifier pump lasers Typical pulse-to-pulse energy stability of diode-pumped lasers <1%, lamp-pumped <3% Reliability The system should operate 24x7 Pumping system Life time of the flash lamp – about 300-500h => Changing Lamps every ~2wks Laser Diode Lifetime ~ 10000hr (~1year) UV conversion unit Shaping hardware Short rise/fall time Requires temporal pulse shaping Amplification and UV conversion can affect the pulse shape Broad bandwidth required for the temporal shaping reduces the efficiency of UV conversion 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

R&D Effort UV Conversion and Spatial Shaping (ANL/SLAC) Modeling of the UV conversion using SNLO software Harmonic generation data using TiS CPA laser at ANL Study effects of spatially flattened IR pulse after SHG and THG (Spatial Shaping of UV pulses has been done at SLAC) Verify relay imaging of flattened UV pulse over extended distances Study anamorphic and time slew conditioning of UV launch optics (especially grating efficiency) Investigate UV grating damage threshold Sasha Gilevich 08/11/2004 Drive Laser Overview Gilevich@slac.stanford.edu

Spatial Profile Flattening of Ultraviolet Laser Pulses with Aspheric Refractive Optics B.F. Murphy, P.R. Bolton, A. Brachmann, J.F. Schmerge The results of using the IBM refractive aspheric beam shaper at the output of the GTF laser (2psec, 263nm, 500μJ) 20 40 60 80 100 120 140 0.005 0.01 0.015 0.02 50 100 150 200 2 4 6 x 10 -3 Input Output

Temporal Pulse Shaping (BNL/INFN/SLAC) R&D Effort Temporal Pulse Shaping (BNL/INFN/SLAC) Install INFN purchased Dazzler Study effects of amplification on pulse shape Study effects of third harmonic conversion on pulse shape Use shaped laser beam in electron beam experiments Sasha Gilevich 08/11/2004 Drive Laser Overview Gilevich@slac.stanford.edu

Temporal Pulse Shaping with the Dazzler Preliminary Results Using an Acousto-optic Dispersive Filter For Laser Pulse Shaping A Ghigo, F. Tazzioli, C.Vicario, S. De Silvestri, M. Nisoli, S. Stagira, I Boscolo, S. Cialdi, L. Serafini INFN Tests with Dazzler (INFN) integrated in Ti:S drive laser will begin at BNL/DUVFEL in September 04 08/11/2004 Sasha Gilevich Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu

Summary UV Specifications Defined R&D effort is defined and started Details of the Drive Laser RFP defined Several vendors showed capability to build the system Major Issues Stability Reliability Beam Shaping 08/11/2004 Sasha Gilevich Drive Laser Overview Gilevich@slac.stanford.edu