Development and plans for FLASH

Development and plans for FLASH

S. Schreiber, DESY

presented by Albrecht Wagner

FLASH – a free-electron laser user facilityLinac components

Performance and operational issuesUpgrade

ICFA Seminar

October 18-31, 2008SLAC

FLASHFree-Electron Laser

in Hamburg

S. Schreiber – FLASH – ICFA Seminar 30-Oct-2008

FLASH

FLASH at DESY


in Hamburg


FLASH at DESY Hamburg

• FEL user facility since 2005• Photon wavelength range from vacuum

ultraviolet to soft x-rays• Single-pass high-gain SASE FEL

SASE = self-amplified spontaneous emission

• First lasings:Jan 2005 – 32 nmApr 2006 – 13 nmOct 2007 – 6.5 nm

• User experiments 1st period: June 2005 – March 20072nd period: November 2007 – April 2009

• FLASH is also a test bench for the European XFEL and the ILC


in Hamburg


Progress towards short wavelengths

FEL at TTF 1 (upgraded into FLASH in 2003)Proof-of-Principle for SASE in the VUVFirst Lasing 2/2000, Saturation 9/2001

20 40 60 80 100 120 140 160 180

200

400

600

800

1000

Ele

ctro

n B

eam

Ene

rgy

(MeV

)

FEL Wavelength (nm)400 800

Lasing at 13 nm 4/2006,

Lasing at 32 nm 1/2005

Lasing at 25 nm 12/2005

Lasing at 6.5 nm 10/2007

2

2 12 2

uph

K⎛ ⎞λλ = +⎜ ⎟γ ⎝ ⎠

Fixed gap undulator:

Saturation at all wavelengths


in Hamburg


calibrated ion signal – average energy

single bunch signal from electrons

GMD - gas monitor detector - signal

max.

averageactual

FLASH design goals reached

Lasing at 6.5 nmElectron beam energy

of 1 GeV

Lasing with a complete bunch train of 800 bunches @ 13.4 nm

800 µs @ 0.6nC

char

ge (n

C)

1 MHz, 800 bunches

Averaged over 125 pulses


in Hamburg


FLASH overview

RF gun

315 m

Bunch Compressor

Bypass

UndulatorsCollimator

Bunch Compressor

5 MeV 130 MeV 470 MeV 1000 MeV

Accelerating StructuresDiagnostics

FEL Experiments


in Hamburg


Electron source

• Laser driven photoinjector• PITZ: injector test facility at DESY/Zeuthen

long pulse trains of up to 800 µs @ 5 Hz10 kHz to 1 MHz pulse separation within the traincharge for SASE operation: 0.5 nC – 1 nCtransverse emittance ~1.5 mm mrad

• Longitudinal phase spaceUltra-short bunch spikes created (< 60 fs fwhm)

→ ultra-short femtosecond FEL pulses

• Upgrade: 3rd harmonic sc cavities to flatten of the longitudinal phase space

→ more regular compressed bunch shape

Laser

RF-Gun


in Hamburg


Accelerating modules

• Six TESLA type accelerating moduleseach having eight 9-cell superconducting niobium cavities operated at 1.3 GHz

• Energy upgrade to 1 GeV in 20076th module installed3rd module replaced by a new onetuners of 5th module repaired

• Both new modules ≥ 25 MV/m

4 cavities of ACC6 reach even 30 MV/m

AC

C2

AC

C4

AC

C5

AC

C3

AC

C6

TTF1

TTF1

TTF1


in Hamburg


Undulator and photon beam lines

• High-gain single-pass FEL requires a long undulator system

total length 27.3 mpermanent NdFeB magnetsfixed gap of 12 mm

• FEL radiation guided to the experimental hall

• Five photon beam lineslarge variety of experimental possibilitiesbeam is sent to one line at a given time, typ. for a shift of 12 h

BL3

FIR -Beamline

visible laser light

FEL radiation

BL2BL1 PG2 PG1


in Hamburg


SASE performance

Typical user operation parameters: • Wavelength range (fundamental) 7 - 47 nm • Average single pulse energy 10 - 50 µJ• Pulse duration (FWHM) 10 - 50 fs• Peak power (from av.) 1 - 5 GW• Average power (example for 500 pulses/sec) ~ 15 mW• Spectral width (FWHM) ~ 1 % • Brilliance 1029 - 1030 B

In saturation at 13.7 nm:• Average energy 70 µJ• Peak energy 170 µJ• Pulse duration 10 fs• Peak power >10 GW• Peak brilliance (6 ± 3) 1029 B

“Operation of a free-electron laser from the extreme ultraviolet to the water window”

Nature photonics 1 (2007) 336

B = Photons/(s mrad2 mm2 0.1% BW)


in Hamburg


Operational highlights

• User experiment with 5th harmonics of 7.97 nm: 1.59 nm• 5 days continuous running with 100 bunches @ 500 kHz

for two user experiments wavelength of 7.05 ± 0.1 nmaverage SASE level ~30 μJ (14 mW average power)

Wavelength (nm) Bunch Number

User run at 7nm with 100 bunches


in Hamburg


Peak Brilliance

• Unprecedented peak brilliance

• Femtosecond pulsed coherent radiation in the VUV to soft X-rays

• Peak brilliance ~1029 to ~1030

photons/s/mr2mm20.1%bw• Measured Peak Brilliance

agrees with theoretical prediction


in Hamburg


FEL user experiments• World-wide unique light source

ultra-short FEL pulses (femtosecond range)unprecedented brilliancephoton wavelengths down to 7 nm

• Experiments on many different fieldsdiffraction imagingsolid state-, plasma-, and cluster-physicsfemtosecond-chemistry, molecular-biology…

• Single-shot measurements• Pump-and-probe experiments• During the first user period (June 2005 – March 2007)

18 projects received beam time> 200 scientists, 60 institutes, 11 countries

• > 25 publications already, many more to comehttp://hasylab.desy.de/facilities/flash/publications


in Hamburg


Example: diffraction imaging


in Hamburg


Organization of beam time

• FLASH runs 24 hours per day, 7 days per week• Beam time always overbooked• The second user period started in November 2007

and continues until April 2009~ 250 days scheduled for user operationdistributed in 4-week blocks

• Between user blocks, we have study weeks

FEL physics studies, improvements of the FLASH facility, preparation of next user blocksgeneral accelerator studies

• 2-3 weeks three times per year• related to e.g. XFEL and ILC

NJW1

Slide 15

NJW1 Perhaps this slide could be skipped for the seminar if talk too long.

Add comment wrt to Accelerator Studies time to following slide?Nicholas J. Walker, 10/13/2008


in Hamburg


Time distribution during user runs

Scheduled maintenance

SASE FEL radiation delivery

73%

Set-up

Tuning

Down

17%

1% 6%3%

User Block 1 2 3 4 5

SASE 71 79 75 67 69

Tuning 14 13 16 24 18

Set-up 2 1 1 1 2

Maint. 4 4 2 2 1

Down 9 3 6 6 10

numbers in %

5 blocks of 4 weeks each (Nov-2007 to Sep-2008)


in Hamburg


• Fixed gap undulator → wavelength change requires change of the electron beam energy → adjustments of

accelerating gradient and phases beam optics orbit through undulatoroften also bunch compression

• By now, during the second user period: wavelength changed > 60 times, 24 different wavelengths between 27 nm and 7 nm delivered to users

many more wavelengths will come• During the first user period:

several other wavelengths from 47 nm to 13.5 nm delivered as well

Wavelength change

Wavelengths delivered for users Nov 2007- Sep 2008

7 nm 15.7 nm

7.05 nm 17 nm

8 nm 19.2 nm

9.65 nm 20.2 nm

10.6 nm 20.9 nm12.4 nm 22.8 nm12.6 nm 23.2 nm

12.7 nm 24 nm

13.3 nm 25.5 nm

13.5 nm 25.9 nm

13.7 nm 26.1 nm

14.8 nm 27 nm


in Hamburg


Upgrade Plans

• Continuous beam operation until summer 2009• Upgrade in 2009: major modifications

installation the 3rd harmonic (3.9 GHz) module (Fermilab)installation of the 7th accelerating module → energy up to ~ 1.2 GeVinstallation of an experiment for seeded VUV radiation “sFLASH”

• replacement of complete electron beam line between collimators and SASE undulators (~ 40 meters)

exchange of the RF gunupgrades of RF stations and waveguide distribution

• Commissioning in winter 2009/2010 • The third FEL user period is foreseen to start in spring 2010• Beyond this upgrade: proposal for a 2nd beamline


in Hamburg


Accelerator Upgrade

• Increase energy with a 7th module to ~1.2 GeV→ lasing at 4.5 nm→ approaching the water window with the fundamental

• Flatten the longitudinal phase space with a 3rd harmonic cavity in the injector (FNAL/DESY)→ easier and more reliable bunch shapening→ from femtosecond pulses to longer FEL pulses with ~10x the energy


in Hamburg


sFLASH

• High Harmonic Laser Seeding at 30nm• To be installed between the linac and the X-ray FEL

undulator (needs long e-bunches/3rd harmonic cav)

(Pump-probe) synchronisation goal ~ 10 fs


in Hamburg


FLASH II

• 2nd tunnel with undulator beamline and experimental area• With seeding experiments and variable gap undulators• DESY/BESSY proposal

FLASH I

FLASH II


in Hamburg

TTF2/FLASH as an Accelerator Test Facility

• Three projects based on TESLA SCRF technology

• TTF2/FLASH is world-wide a unique test-bed for this technology

• ILC-driven example: 9mA full beam-loading experiment

XFEL ILC FLASHdesign

FLASH 9mA experiment (goal)

Bunch charge nC 1 3.2 1 3# bunches 3250* 2625 7200* 2400Pulse length μs 650 970 800 800Current mA 5 9 9 9


in Hamburg9mA Experiment: Context

• Experiment addresses needs of ILC, XFEL and FLASH– ILC: International GDE stated milestone

• primary driver: important and visible deliverable for international effort

– XFEL: Close collaboration with world-wide LLRF groups• Focus (potentially accelerate) development and planning for XFEL• “Operation at limits” experience provides important Input for future

XFEL development– Important demonstration also for XFEL

– FLASH: Addresses many operational issues• Automated exception handling and recovery• Better characterisation of machine• Towards routine high-power long-pulse operation for photon users.

• Growing International Collaboration (ILC-driven)– ANL, DESY, FNAL, KEK, SACLAY, SLAC

XFELX-Ray Free-Elect ron Laser


in HamburgPreliminary Results

FLASH operations records• Long bunch trains with

3nC per bunch:550 bunches at 1MHz300 bunches at 500KHz890MeV linac energy

• All modules running with 800us flat-top and 1GeV total gradient

John Carwardine Global Design Effort 24

All RF stations with 800us flat top

550 bunches at 1MHz, 3nC/bunch, 890MeV

• Limited to 1MHz (3mA) during first (preparatory)experiments

• 6 kW achieved• 2009 goal: 36 kW (9mA)


in Hamburg


Summary

• FLASH is an world-wide unique light source photon wavelength range from ~ 50 nm down to 7 nmultra-short FEL pulses (femtosecond range)unprecedented brilliance

• Since summer 2005, user FEL experiments in many different fields have been successfully performed

• Continuous beam operation until summer 2009• Upgrade in 2009

increase beam energy to 1.2 GeV3rd harmonic cavityseeding experiment sFLASH

• Proposal for a 2nd beam line (FLASH II)• FLASH is an world-wide unique Test Facility for SCRF

technologyXFEL, ILC (and FLASH itself!)International effort underway to demonstrate 9mA stable beam at operational limits

Documents

Development and plans for FLASH