fermi@elettra - società italiana di fisica · c. callegari): structure of nano-clusters high...
TRANSCRIPT
L. Giannessi
ENEA & ELETTRA-Sincrotrone Triseste
on behalf of the FERMI Commissioning Team
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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
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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)
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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
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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)
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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
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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
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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)
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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
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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
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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)
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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)
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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
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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
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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
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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.)
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PhotoPhoto--Injector Laser Injector Laser pulse shapingpulse shaping
G. Penco et al., JINST 8, P05015 (2013)
Nominal Ramp
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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)
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“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..
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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