Injector Drive Laser Overview Sasha Gilevich SLAC Lehman

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 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 1

UV Beam Specifications at Photocathode Parameter Nominal spec Tolerance wavelength 255 nm nom. +/- 3 nm Longer wavelength requires higher energy pulse energy > 0. 20 m. J < 2 % rms variation (for 1 n. C production with 3 x 10 -5 QE) fluence profile Uniform (nom. ) (adjustable) < 10 % (peak-to-peak) spot radius 1. 2 mm < 4 % (shot-to-shot) Centroid pos. < 10 % radius rep rate 120 Hz (10 to 120 Hz) power profile Uniform < 5% (RMS noise on the (adjustable plateau slope – 10% to +20%) 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 08/11/2004 Drive Laser Overview (RMS over multiple shots) (shot-to-shot) Sasha Gilevich@slac. stanford. edu 2

Sector 20 Laser Bay Drive Laser Heater Transport Tube 10 m Accelerators RF Gun UV Launch and Condition. 08/11/2004 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 3

Layout of Laser Room at S 20 • Space & Utilities for 2 Drive Lasers 08/11/2004 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 4

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 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 5

Drive Laser Structure Dazzler 08/11/2004 Drive Laser Overview 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 Sasha Gilevich@slac. stanford. edu 6

UV Launch System Steering Stabilization Flattener Spatial Shaper Launch Grating Cathode Window Telescope lenses 08/11/2004 Drive Laser Overview Grating and Trimmer Sasha Gilevich@slac. stanford. edu 7

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 24 x 7 Pumping system Life time of the flash lamp – about 300 -500 h => Changing Lamps every ~2 wks Laser Diode Lifetime ~ 10000 hr (~1 year) 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 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 8

R&D Effort UV Conversion and Spatial Shaping (ANL/SLAC) Modeling of the UV conversion using SNLO software Harmonic generation data using Ti. S 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 08/11/2004 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 9

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 (2 psec, 263 nm, 500μJ) 0. 02 Input x 10 -3 Output 6 0. 015 4 0. 01 2 0. 005 0 20 40 60 80 100 120 140 0 50 100 150 200 10

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 08/11/2004 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 11

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 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 12

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 Drive Laser Overview Sasha Gilevich@slac. stanford. edu 13