Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20071

Lasers and Ultra-precise Timing

Injector Laser and CommissioningInjector Laser review

Commissioning Experience

Updates to transport and controls

Hand-off to operations

Ultra-precise timingLBNL Collaboration

Status

NEH Laser Status

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 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

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20073

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

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20074

Accomplishments

•Great Up Time!

•20 weeks of commissioning

•Three 8 hour downs – Hot swappable parts will be here before next run

•One 3 hour down – my fault

•2 hours per week for locking problems

•98% up time

•Solved spatial flutter problem – further improvement expected

•>500 J on Cathode – spec was 250

•<1.5% rms stability – spec was 2%

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20075

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.

Tubes cleaned last week

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20076

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

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

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20077

New master oscillator from Femtolasers

• Narrower bandwidth requested to have higher spectral intensity and get a better seeding in the Regen (before FWHM = 30 nm)

• Crystal is sealed in airtight cavity to avoid contamination (no more weekly cleaning, endurance test made during 200 hours)

• Remote starting capability

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20078

New Femtolock driver for the oscillator

• Oscillator is first locked to 119 MHz and then to 476 MHz : no more 476 MHz bucket ambiguity.

• Lock button added to be lock always on the same bucket.

• RF- locking loop and lock button can be run remotely.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 20079

Jedi Pump Laser

Failure of Q-switch driverWe diagnosed.Thales rushed a board and technician to us.3 Days lost

Various chiller problemsNow have local source of spares

Began purchasing spares in November

CR Delayed order placementShould receive in AugustHot swappable spares

Spare Jedis are installed and operational

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200710

Commissioning Issues

Cross correlatorStreak Camera

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200711

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

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200712

Temporal Pulse Shape - Now

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200713

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

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200714

Beam

Attenu

ator

Pulse Stacker

Iris Wheel

Zoom Telescope

Insertable

Power Meter

Insertable

Power Meter

Active Steering

Stabilization

New Transport Layout

UV BeamOutput

Vacuum Tube

to Gun

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200715

Option of Focusing the Beam on the Cathode

Transport tube

Table in the

tunnel

Photocathode

Steering system

Active Steering

Stabilization

F4=F5=5000

F6=1500

L4

L5

L6Shutter

LDave

Removable Lens LDave F=3m

Z-adjustment of L6 changes the beam size on the cathode

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200716

No Major Changes to Vault Transport

M5

L5

M4

L6 M3

M2

VC Power Meter

Cathode

M1

C1

C2 UV plates for Cameras

Cathode Cleaning Lens

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200717

SparesWe do not have a complete hot swappable laser system.Two Spare Jedis, power supplies and chillers have been received and installedMillenia pump laser and spare chiller has been received and installedWe believe all long lead items that could fail are now covered with spares

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200718

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

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200719

Normal Operations

The daily operation of the laser which, with the new transport system and oscillator, will be controlled from MCC. This will be the responsibility of the Accelerator Operations Department. Training of the operators, documented operating procedures as appropriate, and support during the transition will be the responsibility of the Laser Group. Operating procedures and documentation must conform to the document control policies of the Accelerator Operations Department. The Laser Group is responsible for ensuring that engineered protection systems are in place to ensure the safety of personnel and the protection of the equipment.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200720

Daily or Shift-wise Parameter Logging:

The Laser Group is responsible for developing control-system based facilities and software to monitor and record laser parameters as needed to support the efficient operation and maintenance of the laser systems. These facilities will function automatically as much as possible; however, some logging activities may require operator intervention on a daily or shift-by-shift basis. The Accelerator Operations Department staff will work with the Laser Group to develop efficient ways to achieve this.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200721

Scheduled Maintenance:

Maintenance of the laser and associated equipment will be the responsibility of the Laser Group who will work with the Accelerator Operations Department to develop policies and procedures that work for both groups, within the established ASD framework for coordinating accelerator maintenance activities.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200722

Unscheduled Problems:

This will be the responsibility of the Laser Group who will designate someone on call during commissioning shifts. The Laser Group will also provide the Accelerator Operations Department with a pager number and/or call list to expedite contact with a qualified laser person when a problem arises whenever the laser systems are scheduled to be operated. The information will be provided in the form of one or more pages that can be incorporated directly into the ASD Call-In Lists binder.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200723

LCLS High Precision Timing

SLAC/LBNL collaboration to develop system for high precision (<100 fsec) delivery of timing reference from RFPC laser to X-ray Endstations.

SLAC/LBNL MoU signed and project goals and responsibilities specified

30 month project with Aug 07 start with ~$2.1M budget for LBNL

LBNL project team assembled. SLAC contacts identified.

Conceptual design review planned for late Nov.-early Dec. 07

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200724

Development Status

• Transmission of S-band master oscillator over optically stabilized fiber shows <40 fsec stability over 24 hours using feedforward correction for group/phase velocity dispersion.

• Still tracking down systematic effects with possible improvement

• System now installed in chassis for tests in SLAC tunnel

CWfiberlaser

freq.shifter

delayAM

phase delay control

networkanalyzer(phase)

reference

signal

2kmfiber

2.8GHz

feed-forwardcorrector

stableoutput

group error asfiber heats

1.6% correction added

36fsRMS

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200725

RF transmission design

Design of final timing system in progress.

Procurement of components in progress.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200726

Timing PlansThree main phasesPhase I

Stabilize an optical fiber in SLAC tunnel and klystron gallery using already built LBNL hardware. Goal is to understand relative thermo-acoustic environment. Hardware returns to LBNL after test.

Transmit RF over stabilized fiber in loopback mode (i.e. loop fiber back to source).

Perform attenuation vs. time measurements of fiber to look at radiation damage effects.

Phase 2Build core of LCLS timing stabilization hardware

provide digitally controlled GVD correction

engineer digitally controlled transmitter and receiver

develop system diagnostics

provide basic connectivity to LCLS controls

Install and test at LCLS

Phase 3Specify (LBNL), procure and install (SLAC) fiber for final timing

Deliver, install, and test final LCLS timing system (4 stabilized fiber lines, expandable to 16)full system diagnostics and controls

full connectivity to LCLS controls

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200727

The NEH has a centralized laser bay which transports beams to 3 experimental hutches

Near Experiment Hall Laser Bay Floor

Laser HallLCLS X-ray

BeamTo Far Hall

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200728

The 3 experimental hutches are located one floor below the laser bay

Laser Bay

Transport TubesHutch 1

AMO

LUSI XPP

Sub-Basement of Near Experiment Hall

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200729

Near Hall Lasers

NEH LSS design underwayPDR held on Oct. 18

ESD and SOP next

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200730

Main Control of the LSS is in the Laser Hall

Laser BayLSS Control

Panel

Door Interlocks

LSS Status Sign

LSS Status Sign

Cra

sh

Pa

ne

l

Transport Shutters

LASER OFF

Door Bypass

Badge Reader

Door Interlocks

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200731

Near Hall LasersNEH LSS design underway

PDR held on Oct. 18ESD and SOP next

AMO LaserPRD coming soonPurchased for delivery in October 08

LUSI XPP Laser Will use AMO laser for initial experimentsDedicated laser in 2011 or 2012Interface with XPP has been defined, interface document soon.

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200732

SummaryInjector laser

Modifications for automation underwayProcedures under developmentHand-off begins JanuarySpares are here

Precision TimingProject is finally officially underwayPrototype will be tested during next run

NEH Lasers LSS design underwayLaser procurement process beginning nowReceive laser in October 08

Bill White

Lasers and Ultra-precise Timing b.white@slac.stanford.edu

October 29, 200733

End