L. Giannessi

ENEA & ELETTRA-Sincrotrone Triseste

on behalf of the FERMI Commissioning Team

1

FERMI@FERMI@ElettraElettra LLa a prima sorgente FEL con seme in prima sorgente FEL con seme in ingresso operante nei raggi Xingresso operante nei raggi X

2

FERMIFERMI

Externally seeded VUV - Soft Xray FEL USER facilities in the world

ELETTRA Synchrotron Light Source: up to 2.4 GeV, top-up mode, ~800 proposals from 40 countries every year

FERMI FEL-1 & FEL-2 : 100nm to 4 nm

High Gain Harmonic Generation FEL (HGHG)

~70 proposals from first two calls for experiments in 2012/2013

FERMI and ElettraFERMI and Elettra

Sponsored by

Italian Minister of University and Research (MIUR)

Regione Auton. Friuli Venezia Giulia

European Investment Bank (EIB)

European Research Council (ERC)

European Commission (EC)

11

FEL1

FEL2 I/O mirrors & gas cells

PADReS

DIPROI

Photon Beam Lines

slits

experimental hall

undulator hall

Transfer Line

FEL-1

L1

X-band

BC1

L2 L3 L4

BC2

Electron linear accelerator tunnel

PI

Laser Heater

HE-RFD

1.2 → 1.5 GeV

FERMI LAYOUTFERMI LAYOUT

LE-RFD

FEL-2 FEL FEL --1: 1: Single stage cascaded FEL, full specifications achieved in 2012, Single stage cascaded FEL, full specifications achieved in 2012,

now dedicated to user experimentsnow dedicated to user experiments

•• Continuously tuneable in the wavelength range 20Continuously tuneable in the wavelength range 20--65 nm 65 nm (up to 100nm (up to 100nm

possible with specific machine possible with specific machine setup; down to 12.3 nm in specific test experiments)setup; down to 12.3 nm in specific test experiments)

•• Bandwidth (best) 5x10Bandwidth (best) 5x10--44 @ 32 nm@ 32 nm

•• Energy per pulse Energy per pulse 3030--100 uJ 100 uJ ((depending on wavelength setting depending on wavelength setting –– up to a factor 2up to a factor 2--3 3

more relaxing the spectral purity requirements) more relaxing the spectral purity requirements)

Fresh beam 5

Seeded FEL amplifierSeeded FEL amplifier

modulator High gain radiator tuned at nth harmonic Seed

THG or tuneable OPA

dispersion

e-beam

Modulated beam

Seed

Bunched beam

modulated e-beam

nth harmonic radiation

Transverse Coherence

@ 26 nm (h10)

≈ 250 μJ Taper Δλ/λ ≈ 0.9%

@ 20 nm (h13)

≈ 90 μJ Offset Δλ/λ ≈ 0.9%

2200s Mean 320 μJ

@ 52 nm (h5)

h25

h27

FERMI FELFERMI FEL--1 1 –– NominalNominal rangerange 100 100 –– 20nm 20nm

11

FEL1

FEL2 I/O mirrors & gas cells

PADReS

DIPROI

Photon Beam Lines

slits

experimental hall

undulator hall

Transfer Line

FEL-1

L1

X-band

BC1

L2 L3 L4

BC2

Electron linear accelerator tunnel

PI

Laser Heater

HE-RFD

1.2 → 1.5 GeV

FERMI LAYOUTFERMI LAYOUT

LE-RFD

FEL-2 FELFEL--2: 2: Double stage, fresh bunch, cascade FEL, in commissioningDouble stage, fresh bunch, cascade FEL, in commissioning

October 2012 commissioning @October 2012 commissioning @ 1.0 GeV, 14.4 nm & 1.0 GeV, 14.4 nm & 10.8 nm ≈50 uJ @10.8 10.8 nm ≈50 uJ @10.8 nmnm

Extended wavelength range down to 8 nm in March 2013 (@1.23 GeV) Extended wavelength range down to 8 nm in March 2013 (@1.23 GeV) commissioningcommissioning

Down to 5 nm and below in June 2013 (@1.4 GeV)Down to 5 nm and below in June 2013 (@1.4 GeV)

8

The Fresh Bunch The Fresh Bunch Injection Technique*Injection Technique*

Two HGHG FELs stages • The first stage is seeded by the Ti:Sa 3rd harmonic

• The second stage is seeded by the first stage FELby the first stage FEL

• The two FELs operate with the same etwo FELs operate with the same e--beambeam

*L. H. Yu, I. Ben-Zvi, Nim 1993

1st stage 2nd stage

1st mod. 1st rad. 2nd mod. 2nd rad.

Seed at 260nm

DS1 DS2 DL

e-beam Seed

nth harmonic

(e.g. 32.5 nm)

nth x mth harmonic

(e.g. 10.8 nm)

The seed @260nm is on the tail of the e-beam

The first stage converts the seed to the nth harmonic (8th harmonic @32.5nm)

The delay line shifts the first stage output to a fresh portion of the e-beam

The second stage converts the first stage to the nth x mth harmonic of the seed

Position:

The Fresh bunch The Fresh bunch injection techniqueinjection technique

1st mod. 1st rad. 2nd mod. 2nd rad. DS1 DS2 DL

First lasing of FELFirst lasing of FEL--22

STEPSSTEPS

1. Lase with first stage at 43nm, 6th harmonic of the seed

2. Align the first part of the electron orbit with the output of the first stage, and ensure the superposition of “seed” and electrons in the second modulation stage

3. Use filters (Pd, Zr) to cut light at “long” wavelengths and distinguish emission from first and second stage

4. With the delay line off, lase in whole bunch mode, i.e. coherent electron modulation (and induced energy spread) transported from the first to second stage. Optimize orbit and matching to the undulator beamline, also with all the undulators in the second stage tuned at 14.4nm (6th x 3rd harmonic of 260nm)

5. Turn on the delay line verifying the stability of the orbit and optimize output vs. seed intensity and vs. the first and second dispersive sections strength

First light with delay line on (in fresh bunch mode) on October 11th 2012

October 12th 2012 DELAY LINE R56 105 -170 microns ≈ 170-250 fs

6th x 3rd harmonic of the seed (260nm)

14.4nm S

pe

ctr

um

11

FELFEL--2 First 2 First commissioning shifts*commissioning shifts*

Narrow linewidth, single mode spectrum @ 10.8nm

Gaussian like transverse mode

During the October run the FEL was optimized at 10.8nm (24h)

E. Allaria et al. “Two Stage, Seeded Soft X-Ray Free-Electron Laser”, accepted for publication in Nature Photonics

12

A proof of A proof of “fresh bunch” effect“fresh bunch” effect

mod. 1st rad. 2nd mod. 2nd rad. DS1 DS2 DL

The sensitivity of the output intensity to dispersion BEFORE and AFTER the second modulator is very different Energy modulation is occurring on fresh electrons at the 2nd modulator

Data analisys from Oct. 2012

Lg=2.2m e.g.: I=300A, E=1.0GeV,

sE=600keV, e=1 mm mrad, b=15 m Data Analysis by E. Allaria

Second stage at 3rd harmonic of the 8th

(260nm32.5nm10.8nm)

Wavelength (nm)

Wavelength (nm)

14

Fresh bunch: Seed Fresh bunch: Seed delaydelay Beam tail

Beam head

While scanning the seed delay, there is a region where radiation comes only from the first stage

Because of the fresh bunch scheme, the second stage radiation is produced few hundreds of fs toward the head of the bunch.

First stage 32 nm

Second stage 10 nm

Seed delay (ps)

Se

con

d s

tag

e (

a.u

) F

irst sta

ge

(a

.u)

Seed

32 nm

R56 delay

1st stage 2nd stage

10 nm

Tuning the delay line Tuning the delay line between 1between 1stst and 2and 2ndnd stagesstages

The Second stage:

• Large delays, seed shifted outside the beam.

• Small delays the second stage seeding is

not efficient (superposition with first stage). Delay between 1st and 2nd stage (ps)

The first stage is unaffected

Electron beam delay (fs)

Beam tail

Beam head

Seed

32 nm

R56 delay

1st stage 2nd stage

10 nm

16

Tuning the delay line Tuning the delay line between 1between 1stst and 2and 2ndnd stagesstages

The value of the delay line has an impact also on the

final FEL spectrum (wavelength and bandwidth).

When the delay is too large or too small, the pulse

shape is affected -> increase of bandwidth.

Electron beam delay (fs)

Beam tail

Beam head

Seed

32 nm

R56 delay

1st stage 2nd stage

10 nm

Summary of energy vs

wavelength at different energies

17

Coherent emission with FEL-2 has been

obtained down to about 3nm.

Real FEL gain is at

the moment limited

to about 4 nm due to

the electron beam

energy limit.

Increasing the electron Increasing the electron beam energy beam energy -- 4.09 nm4.09 nm Spectra Spectra measured with measured with ee--beam 1.4 beam 1.4 GeV GeV Energy per pulse >Energy per pulse >1uJ (@4 nm)1uJ (@4 nm)

19

FERMI FELFERMI FEL--2 2

78 harmonic of the seed laser (261.3 nm, first stage @6th harmonic & 2 stage @13th harmonic)

Coherent emission at 3.35 nm (about 25nJ)

20

EElectrons lectrons LPS LPS && High High Gain Harm. GenGain Harm. Gen..

modulator radiator

Seed

Chirped e-beam

R56

Compression factor due to dispersion

Δλ

Wavelength shift

• A e-beam linear energy chirp through the dispersive section R56 shifts the FEL wavelength radiation.

• This effect can be compensated by retuning the undulators/seed wavelength.

Blue shift Red shift

21

For a “generic” For a “generic” distributiondistribution

A quadratic chirp (or higher orders) is one of the main causes of Spectral broadening of the FEL

22

Linac elements Linac elements defining edefining e-- LPSLPS

X-band at –p/2

X-band

t

E

t

E

t

E

Accelerating sections

t

E

X-band

t

E

Chicane R56 and T566 Long. Wakes (*that strongly

depend on the current profile)

t

E

BC2

FERMI linac Q=500 pC

Analysis from G. Penco

23

Nominal Nominal FERMI FERMI configurationconfiguration

3

3

2

2106

1

2

1)( tttEtE

1=-1.2 MeV/ps

2=17 MeV/ps2

3=36 MeV/ps3

500 pC flat-top at the inj BC1 compression (x10)

LPS measurement at the end of the linac (by RF Defl. Cavity + En spectr.)

24

PhotoPhoto--Injector Laser Injector Laser pulse shapingpulse shaping

G. Penco et al., JINST 8, P05015 (2013)

Nominal Ramp

25

LPS LinearizationLPS Linearization

500 pC Shaped laser profile to give “flat” phase space at linac exit BC1 at 85mrad (CF~3) BC2 at 70 mrad (CF~3)

1 = -0.04 MeV/ps

2 = 0.3 MeV/ps2

3 = 5.2 MeV/ps3

1 = -0.04 MeV/ps

2 = 0.3 MeV/ps2

3 = 5.2 MeV/ps3

The quadr. chirp is completely suppressed

Core bunch has slice en. Spread of about 150keV

X

Courtesy of F. Capotondi

Looking forward Looking forward (Aug. 2013)(Aug. 2013)

27

“Forward” … this was “Forward” … this was last Friday night: last Friday night:

Courtesy of F. Capotondi and all the

DIPROI collaboration

37.5nm from 1st stage

7.5nm from 2nd stage

Two color diffraction pattern

The success of the FERMI@Elettra project depends on The success of the FERMI@Elettra project depends on the work of the entire FERMI team and of the staff of the work of the entire FERMI team and of the staff of

ElettraElettra--Sincrotrone TriesteSincrotrone Trieste Team organization at http://www.elettra.trieste.it/lightsources/fermi/fermiTeam organization at http://www.elettra.trieste.it/lightsources/fermi/fermi--managementmanagement--page.htmlpage.html

Allaria E., Bencivenga F., Callegari C., Capotondi F., Castronovo D., Cinquegrana P., Craievich Allaria E., Bencivenga F., Callegari C., Capotondi F., Castronovo D., Cinquegrana P., Craievich P., Cudin I., Danailov M.B., De Monte R., Demidovich A., D'Auria G., Dal Forno M., De Ninno G., P., Cudin I., Danailov M.B., De Monte R., Demidovich A., D'Auria G., Dal Forno M., De Ninno G.,

Di Mitri S., Diviacco B., Fabris A., Fabris R., Fawley W.M., Ferianis M., Ferrari E., Finetti P., Di Mitri S., Diviacco B., Fabris A., Fabris R., Fawley W.M., Ferianis M., Ferrari E., Finetti P., Froehlich L., Furlan Radivo P., Gaio G., Gauthier D., Ivanov R., Kiskinova M., Loda G., Lonza M., Froehlich L., Furlan Radivo P., Gaio G., Gauthier D., Ivanov R., Kiskinova M., Loda G., Lonza M.,

Mahne N., Mahieu B., Masciovecchio C., Predonzani M., Principi E., Nikolov I., Parmigiani F., Mahne N., Mahieu B., Masciovecchio C., Predonzani M., Principi E., Nikolov I., Parmigiani F., Penco G., Plekan O., Raimondi L., Rossi F., Rumiz L., Serpico C., Sigalotti P., Scafuri C., Penco G., Plekan O., Raimondi L., Rossi F., Rumiz L., Serpico C., Sigalotti P., Scafuri C.,

Spampinati S., Spezzani C., Sturari L., Svandrlik M., Svetina C., Trovò M., Vascotto A., Veronese Spampinati S., Spezzani C., Sturari L., Svandrlik M., Svetina C., Trovò M., Vascotto A., Veronese M., Visintini R., Zangrando D., Zangrando MM., Visintini R., Zangrando D., Zangrando M..

29

Thank youThank you

Science CaseScience Case

Low Density Matter (coord. C. Callegari):

structure of nano-clusters

high resolution spectroscopy

magnetism in nano-particles

catalysis in nano-materials

Diffraction and Projection Imaging (coord. M. Kiskinova, F.Capotondi): Single-shot & Resonant Transverse Coherent Diffraction Imaging

morfology and internal structure at the nm scale

chemical and magnetic imaging

Elastic and Inelastic Scattering (coord. C. Masciovecchio):

EIS TIMER (F. Bencivenga) Transient Grating Spectroscopy (collective dynamics at the nano-scale)

EIS TIMEX (E. Principi ) Pump & Probe Spectroscopy (meta-stable states of matter)

……………………………………… brightness

………………………… narrow bw, -tunability

…………………………… circular polarization

…………………………… fs pulse and stability

…………………………………… brightness