James Welch [email protected] October 29, 2007 Injector Commissioning Injector...

James Welch

FAC [email protected]

October 29, 2007

Injector Injector CommissioningCommissioning

Injector Commissioning Results presentated to the Facilities Advisory Committee, October 2007, by J. Welch on behalf of the LCLS Commissioning Team.

James Welch


October 29, 2007

IntroductionIntroduction

Last April

Today

Commissioning plans

James Welch


October 29, 2007

Injector LayoutInjector Layout

OTR screens (7)OTR screens (7)YAG screens (7)YAG screens (7)Wire scanners (7)Wire scanners (7)Dipole magnets (8)Dipole magnets (8)Beam stoppers (2)Beam stoppers (2)S-band RF acc. sections (5)S-band RF acc. sections (5)

RF GunRF Gun

GunGunSpectrometerSpectrometer

RFRFDeflectorDeflector

X-band RFX-band RFacc. sectionacc. section

BC1BC1L1SL1S

L0aL0a

L0bL0b

2-km point in 3-km SLAC linac2-km point in 3-km SLAC linac

135-MeV135-MeVSpectrometerSpectrometer

EmittanceEmittanceScreens/WiresScreens/Wires

EmittanceEmittanceScreen/WiresScreen/Wires

135 MeV135 MeV

6 MeV6 MeV

250 MeV250 MeV

TD11TD11stopperstopper

(not to scale)(not to scale)

UV laser

James Welch


October 29, 2007

Summary April 16, 2007Summary April 16, 2007(Last FAC Meeting)(Last FAC Meeting)

Beam transported to all areas. No trouble, but no systematic Beam transported to all areas. No trouble, but no systematic checkout yet.checkout yet.

Controls still under development, but working well and improving Controls still under development, but working well and improving fast – great cooperation and effortfast – great cooperation and effort

Communication with laser group excellentCommunication with laser group excellent

Screens and toroids late, but installation continuedScreens and toroids late, but installation continued

Some quality control issues with a few componentsSome quality control issues with a few components

April 5April 5: : First First ee from gun (6 MeV) from gun (6 MeV)

April 8April 8: : First First ee to inj-spectrometer (135 MeV) to inj-spectrometer (135 MeV)

April 14April 14:: First First ee through BC1 (250 MeV) through BC1 (250 MeV)

James Welch


October 29, 2007

Where We are NowWhere We are Now

Commissioning ResultsAll Injector Commissioning Goals achievedAll Injector Commissioning Goals achieved

xx & & yy emittanceemittance 1.2 1.2 mm at at 1 nC1 nC charge (design) charge (design)

<1.5%<1.5% rms charge stability (design is 2%) rms charge stability (design is 2%)

Drive laser Drive laser 98%98% up-time with up-time with 500 500 JJ (250 (250

design)design)

Bunch compression in BC1 fully demonstratedBunch compression in BC1 fully demonstrated

Accelerated Accelerated LCLSLCLS beam to 16 GeV (13.6 design) beam to 16 GeV (13.6 design)

X-band & 2 RF deflectors both operationalX-band & 2 RF deflectors both operational

New RF performing within spec (New RF performing within spec (e.g.,e.g., <0.1º rms) <0.1º rms)

Feedback ON: launch, charge, energy, RF, & Feedback ON: launch, charge, energy, RF, & zz

Robust, high-quality RF gunRobust, high-quality RF gun

Remaining problemsGun Faraday cup and toroid don’t workGun Faraday cup and toroid don’t work

BC1 dipole field quality is poorBC1 dipole field quality is poor

Emittance growth from X-band RFEmittance growth from X-band RF

OTR beam size measurements altered by OTR beam size measurements altered by COTRCOTR

Bunch length from injector 30% too long (1.1 Bunch length from injector 30% too long (1.1 mm, but design is 0.85 mm)mm, but design is 0.85 mm)

Wire-scanners vibrateWire-scanners vibrate

Improvements underwayImprovements underway

James Welch


October 29, 2007

2007 Injector Commissioning Goals2007 Injector Commissioning Goals

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James Welch


October 29, 2007

Laser PerformanceLaser Performance

98% up-time with 500 J (250 J design).

Spatial profile and position stability were initially poor, but improved greatly by extending the length of the drift tubes.

Temporal shape (7.1 ps FWHM)Temporal shape (7.1 ps FWHM)Spatial shape on cathode using irisSpatial shape on cathode using iris

7.2 ps7.2 ps8.8 ps8.8 ps

P. Hering. Oct. 8P. Hering. Oct. 8

RR = 0.8 mm = 0.8 mm

James Welch


October 29, 2007

Emittance PerformanceEmittance Performance

design emittance

James Welch


October 29, 2007

Gun QE PerformanceGun QE Performance

Now up to 1 nCNow up to 1 nC

Emission Image of Cathode on YAG

<1.5%<1.5% rms rms charge charge stability stability (design is (design is 2%)2%)

James Welch


October 29, 2007

EPIC ControlsEPIC Controls

MagnetsMagnets LLRFLLRF

CollimatorCollimator

VacuumVacuum

MPSMPS

User App.User App.LauncherLauncher

Heroic and Heroic and successful successful effort by the effort by the Controls GroupControls GroupAlso use SLC ControlsAlso use SLC Controls

James Welch


October 29, 2007

Matlab Application Matlab Application Emittance Measurement - Emittance Measurement - H. LoosH. Loos

Example: emittance measurement

Measure Measure emittance at emittance at chosen location chosen location using 3 OTRs, 3 using 3 OTRs, 3 wires, or quad wires, or quad scan on OTR or scan on OTR or wirewire

Watch profiles as Watch profiles as scan proceedsscan proceeds(avg. ~10)(avg. ~10)

Send results Send results to E-logto E-log

Transverse Wakefield in X-Band StructureTransverse Wakefield in X-Band Structure

xx 0.6 mm 0.6 mm

QQ 700 pC 700 pCzz 1 mm 1 mm

EE = 250 MeV = 250 MeVBC1 OFFBC1 OFFX-band RF OFFX-band RF OFF

xx (

( μμm

)m

)

J. TurnerJ. Turner

X-Band cavity to be re-aligned during this downtime.

James Welch


October 29, 2007

Time Resolved MeasurementsTime Resolved Measurements

RF deflector RF deflector OFFOFF RF deflector RF deflector ONON RF deflector RF deflector ONON

headhead

tailtail

high high EE

EE 6 keV rms 6 keV rms (40 (40 m)m)

at 150 pCat 150 pC

in spectrometerin spectrometer

James Welch


October 29, 2007

14 GeV14 GeV‘‘Max’ CompressionMax’ Compression

0.89 ps0.89 ps

14 GeV14 GeV

135 MeV135 MeV1.10 mm rms 1.10 mm rms

14 GeV14 GeVBC1 Design CompressionBC1 Design Compression

10.3 ps10.3 ps

135 MeV135 MeV

97 A97 A 950 A950 A520 A520 A

1.7 ps1.7 ps

14 GeV14 GeV

PR55PR55

Thanks to Controls GroupThanks to Controls Group

OTR2OTR2 135 MeV135 MeV 14 GeV14 GeVBunch Length Bunch Length MeasurementsMeasurements

James Welch


October 29, 2007

Unexpected Physics! Unexpected Physics! Coherent OTR Coherent OTR

Bunch Length MonitorsBunch Length Monitors

OTROTROpticalOpticalSignalSignal

300 GHz300 GHz

100 GHz100 GHz

RF Phase of L1S, relative to crest (degS)RF Phase of L1S, relative to crest (degS)

Generation of COTR in the Visible Spectrum Indicates Micro-bunch SpikeGeneration of COTR in the Visible Spectrum Indicates Micro-bunch Spike& Interferes with Using OTR Profiles for Emittance Measurements. (~Frisch, & Interferes with Using OTR Profiles for Emittance Measurements. (~Frisch,

Tues 11:30)Tues 11:30)

At max compression OTR Can ProduceAt max compression OTR Can Produce““Ring-Like” Shapes! Ring-Like” Shapes!

OTR Light increases by 10-100 with maximum OTR Light increases by 10-100 with maximum compressioncompression

James Welch


October 29, 2007

B1B1B1B1 B2B2B2B2 B3B3B3B3B4B4B4B4 TD11TD11TD11TD11S-band acc.S-band acc.S-band acc.S-band acc.

BPMBPMBPMBPM

BPMBPMBPMBPM

wire scan wire scan after BC1:after BC1:

xx 1.7 1.7 mm

poor bend field qualitypoor bend field quality

quads quads correct correct xx

no

min

al

no

min

al xx

-po

sitio

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osi

tion

quadsquadsoffoff

read dnstr. BPMs while moving BC1read dnstr. BPMs while moving BC1read dnstr. BPMs while moving BC1read dnstr. BPMs while moving BC1

OTROTR

wire(s)wire(s)

CQ11CQ11 CQ12CQ12

Best Best xx after BC1 with nom. (& more) compression is 1.7 after BC1 with nom. (& more) compression is 1.7 m (& larger)m (& larger)

Poor bend field quality (grad. + sext.) – Poor bend field quality (grad. + sext.) – E/EE/E scan shows 1 scan shows 1stst & 2 & 2ndnd-order -order xxBends being upgraded + need shorter bunch (1.1Bends being upgraded + need shorter bunch (1.1 0.85 mm – less chirp) 0.85 mm – less chirp)

Best Best xx after BC1 with nom. (& more) compression is 1.7 after BC1 with nom. (& more) compression is 1.7 m (& larger)m (& larger)

Poor bend field quality (grad. + sext.) – Poor bend field quality (grad. + sext.) – E/EE/E scan shows 1 scan shows 1stst & 2 & 2ndnd-order -order xxBends being upgraded + need shorter bunch (1.1Bends being upgraded + need shorter bunch (1.1 0.85 mm – less chirp) 0.85 mm – less chirp)

best emittance transferbest emittance transfer

xx minimized with quads minimized with quadsxx minimized with quads minimized with quads

BC1 Emittance GrowthBC1 Emittance Growth

James Welch


October 29, 2007

Fix for BC1 DipolesFix for BC1 Dipoles

Modifications include wider poles (180 instead of 100 mm) and new pinning scheme for yokes.

James Welch


October 29, 2007

Commissioning PlansCommissioning Plans

1.2 km of existing linac (including new bunch compressor BC2)

~308 m of new transport line, LTU, up to Tune-up Dump at the beginning of Undulator hall.

200 m of Undulator and Dump Line

Commission the FEL X-Ray beam itself

Commission the X-Ray diagnostics and beamlines

“FEE” X RayDiagnostics

“NEH” hutches

Xray Tunnel

Existing and refurbishedhousing

Undulator

New housing construction. Completion by ~ Mar. 08

LTU: Linac to UndulatorFEE: Front End EnclosureNEH: Near Experimental HallFEH: Far Experimental HallBC1(2): Bunch compressors

ElectronDump

“FEH”hutches

Injector

Linac

BC1250 MeV

BC24 GeV

“LTU”

Frisch

Welch

Nuhn

Tompkins

James Welch


October 29, 2007

Linac/BC2

FEE/NEH/X-Ray Tunnel/FEH Installation

Timeline of Installation and CommissioningTimeline of Installation and Commissioning

JJ AA SS OO NN DD JJ FF MM AA MM JJ JJ AA SS OO NN DD JJ FF MM AA MM JJ JJ

Linac/BC2 Linac/BC2 Commissioning Commissioning

20072007 20082008

LTU/Und/Dump LTU/Und/Dump Commissioning Commissioning

AA SS OONN DD

20092009PPS

PPS

Controls Controls checkout & re-checkout & re-

commission commission InjectorInjector

Re-Re-commission commission

Inj/BC2 to SL2Inj/BC2 to SL2

FEL/FEE FEL/FEE Commissioning Commissioning

……InjectorInjectorCommissioning Commissioning

NowNow

PPS

PPS

1st Spont. Light1st Spont. Light 1st Users1st Users

downtime

commissioning

LTU/UND/Dump Installation

1st FEL1st FELLightLight

installation

James Welch


October 29, 2007

FEL Commissioning TimelineFEL Commissioning Timeline

James Welch


October 29, 2007

Thanks to All !Thanks to All !CommissionersCommissioners

Laser GroupLaser Group

OperationsOperations

ControlsControls

Power ConversionPower Conversion

MFDMFD

VacuumVacuum

FacilitiesFacilities

Acc. R&DAcc. R&D

MetrologyMetrology

ES&H (RP)ES&H (RP)

Mechanical DesignMechanical Design

Materials ScienceMaterials Science

FacilitiesFacilities

Klystron/RFKlystron/RF

SSRL/GTFSSRL/GTF

Acc. SystemsAcc. Systems

LCLS project personnelLCLS project personnel

Results are very positive and credited to a large, Results are very positive and credited to a large, dedicated group of people at dedicated group of people at SLACSLAC

Core group:Core group:3 shifts/week3 shifts/weekno weekends offno weekends off5 months5 months

+ R. Iverson,+ R. Iverson, & J. Schmerge…J. Schmerge…

James Welch [email protected] October 29, 2007 Injector Commissioning Injector...

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