bill white drive laser [email protected] april 16, 2007 1 drive laser...
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Bill White
Drive Laser Operations [email protected]
April 16, 20071
Drive Laser Commissioning Experience
Reminder of requirements on Drive LaserThales laser Transport system
Commissioning in three areasThales laser and it’s specsBeam conditioning and transportVirtual cathode alignment
Lessons learned – remaining issuesFuture
Bill White
Drive Laser Operations [email protected]
April 16, 20072
UV pulse goals
90-10 rise and fall times < 1 psflat-top, < 8% peak-to peak
• 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 ProfileFWHM = 10 ps(5-20 ps)
Bill White
Drive Laser Operations [email protected]
April 16, 20073
Thales Laser system
Oscillator
Stretcher
Dazzler
Regen
Preamplifier
Final Amplifier
Compressor
UV Conversion
Bill White
Drive Laser Operations [email protected]
April 16, 20074
Transport Laser Bay
Launch System
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
Bill White
Drive Laser Operations [email protected]
April 16, 20075
Active Steering StabilizationIn order to meet centroid position stability requirement (min 60μm) M6 should be stabilized with 35μrad accuracySensitivity of the mirror mount 7arcsec – 34 μrad
Camera
CameraFrom Virtual Cathode
To Photocathode
Laser Bay
Transport Tube
Table in the tunnel
Steering Stabilization system test is underway
M6
M5
M4
M3
M2
C2
C1
Bill White
Drive Laser Operations [email protected]
April 16, 20076
Transport System in the Laser Bay
Laser Output
Shaper Input Adjustment
ShaperLensBeam Size Adjustment
Remotely Controlled Mirror
To Transport tube
Bill White
Drive Laser Operations [email protected]
April 16, 20077
Optical System next to the PhotocathodeFrom Transport tube
Lens
Lens
Remotely Controlled Mirror
Remotely Controlled Mirrors
Steering Stabilization Camera
Steering Stabilization Camera
Lead Blocks
Lead BlockVirtual Cathode camera
In vacuum mirrorPhotocathode
Powermeter
Bill White
Drive Laser Operations [email protected]
April 16, 20078
Transport Commissioning
TransportShaper
Diagnostics
Characterization
Calibration of diagnostics
GTL Installation
Virtual Cathode
Bill White
Drive Laser Operations [email protected]
April 16, 20079
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
Bill White
Drive Laser Operations [email protected]
April 16, 200710
Commissioning IssuesBetter 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
Bill White
Drive Laser Operations [email protected]
April 16, 200711
Commissioning Issues
Cross correlatorStreak Camera
Bill White
Drive Laser Operations [email protected]
April 16, 200712
Temporal Pulse Shaping
The achieved temporal pulse shape meets physics requirements for the injector commissioningPlan to improve the temporal shape
Replace the Lyot filter in the regen amplifier by the edge mirrors – this will reduce oscillationsContinue working on the Dazzler settings and the optimum UV conversion crystals lengthsThales engineers are coming back in September to continue working on shaping
Plan B – to use stacking of Gaussian pulsesDesign and parts for pulse stacking are in place
Bill White
Drive Laser Operations [email protected]
April 16, 200713
Commissioning IssuesTransport 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.
Bill White
Drive Laser Operations [email protected]
April 16, 200714
GBS-UV H
Commissioning IssuesNewport aspheric telescope
Converts Gaussian to flat-top
Requires good Gaussian input
Very sensitive to alignment
Aperture is just as good and much simpler to align
Allows flexibilitySimplifies overall transport
Bill White
Drive Laser Operations [email protected]
April 16, 200715
Commissioning Issues
Oscillator ProblemsPicomotor translation stage instability
Femtolase will replace
Coarse control currently disabled/manual
Phase ambiguity due to locking at 476MHz
Impacts phasing of RF
Can make double pulse
Could be solved with newly available upgrade
Replacing this oscillator will solve both problems and provide greater seed energy
Bill White
Drive Laser Operations [email protected]
April 16, 200716
Future - Hand Over to Ops
NowDevelop procedures for laserAutomate things that can and need to be automated
August 07 DownTrain Operations Group on typical Operation ProceduresHand off laser by Jan 08
Laser Group will support Ops Scheduled MaintenanceIssues that arise outside of the typical operation envelope
