A. Doyuran, L. DiMauro, W. Graves, R. Heese, E. D. Johnson, S. Krinsky, H. Loos, J.B. Murphy, G. Rakowsky, J. Rose, T. Shaftan, B. Sheehy, Y. Shen, J. Skaritka, X.J. Wang, Z. Wu, L.H. Yu

National Synchrotron Light SourceBrookhaven National Laboratory

SATURATION of THE NSLS SATURATION of THE NSLS DUV-FEL AT BNLDUV-FEL AT BNL

HGHG FELHGHG FEL

RADIATOR

DISPERSIVE SECTION

MODULATORSEED LASER800 nm, ~ 30 MW

HGHG OUTPUT* 266 nm, ~ 100 uJ, 1 ps (FWHM)* 88 nm, ~ 1 uJ

ELECTRONBEAM

d=3.89 cm, L=10 m, B=0.31 T

d=8 cmL=80 cmB=0.22 T

Deep UV Free Electron Laserat the Source Development Laboratory

Modulator Wiggler : L = 0.8 mw = 8 cmK = 1.67

DispersionMagnet:L = 30 cm = 3 for 30 MW seed laser

Radiator (NISUS) Wiggler:L = 10 m, w = 3.89 cmB = 0.31 T, K = 1.126

A d ju stab leC h ican e

1 7 7M eV

R F ze roP h a sin gP h o to in jec to rC T R M o n ito r

N o rm a l in c id en ce

7 7 M eV

F E L seeda t 8 0 0 n m

M o d u la to r U n d u la to r

N IS U S p o p -inm o n ito rs

F E L M ea su re m en tE n e rg y, S p e c tru m , S y n ch ro n iza tio nan d P u lse L e n g th M easu rem e n tsa t 2 6 6 n m

s

Io n P a ir Im ag in gE x p e rim en ta t 8 8 n m

N isu s W ig g le r

3 0 m J T i:S ap p h ireA m p lifie r

D isp e rs io nM ag n e t T rim C h ican e

Undulator & Electron Beam Parameters

Energy 177 MeVCharge 300 pCNormalized emittance 4 mm*mrad

Compressed bunch length, RMS 0.3-0.6 psEnergy spread, RMS 0.05 %

Period 3.89 cmNumber of periods (length) 256 (10 m)Peak field 0.31 TBetatron wavelength 25 mElectron beam size, RMS (4 mm mrad) 250 um

Undulator NISUS parametersUndulator NISUS parameters

Measured electron beam parametersMeasured electron beam parameters

HGHG FEL hardwareHGHG FEL hardware

9

YAG

Triplet 3

QA QB QA

19 18

Modulator

17

DS

1516

th/tv12 th/tv11NISUS

Spectrometer

Measurements of Electron Beam Properties

Longitudinal beam parametersLongitudinal beam parameters

-1 -0.5 0 0.5 10

100

200

300

400

Time (ps)

rms = 400 fs

Transverse beam parametersTransverse beam parameters

Q = 300 pC

measured by zero-phasing method

Measured by pop-in monitors along the NISUSMatching and alignment is done by automated MATLAB routines

Beam based alignment of NISUS wiggler Beam based alignment of NISUS wiggler

Initial (green) and corrected (blue) Beam trajectories (green) relative beam trajectories along the wiggler to the alignment laser (blue)

NISUS Wiggler Diagnostics

P an cak e M ag n e t a t m ax im u m cu rren t

P an cak e M ag n e ta t o p e ra tio n a l cu rren t

fo r tra je c to ry co rrec tio n

e b eam d iec tr io n

N IS U S p o p -inM o n ito rs

D e tec to rs

Io n P a ir Im a g in gE x p e rim en t

M easu rem en t A rea * Jo u lem e te r* S p ec tro m e te r* S tre ak C am era* A u to co rre la to r

4 -w ire sy s tem

Alignmentlaser

HGHG Gain Measurements

For 30 MW seed power = 3 HGHG saturates at 5th m in NISUS yielding ~100J energy

For 1.8 MW seed power = 8.7HGHG saturates at the end of NISUS

Energy vs. distance along the wiggler

0 2 4 6 8 10

100

102

Wiggler Length (m)

Pul

se E

nerg

y (J

)

(a) 1.8 MW(b) 30 MWTDA

SASE

HGHG

Shot to shot intensity fluctuations forSASE and HGHG

0 10 20 300

1

2E

/<E

>

0 1 20

1

2

3

p(E

)

= 41%

0 10 20 300

1

2

Time (s)

E/<

E>

0 1 20

5

10

E/<E>

p(E

) = 7%

HGHG and SASE measured spectra under same electron beam conditionsHGHG spectral brightness is 2x105 times

larger than SASE spectral brightness

262 264 266 268 2700

0.2

0.4

0.6

0.8

1

Wavelength (nm)

Ene

rgy

(m

J (%

bw

)-1)

SASE 105

HGHG

0.23 nm FWHM

x

SASE spectrum is calculated with GENESIS by H. Loos after 20 m of the NISUS structure to have a fair comparison with HGHGSASE spectral brightness would still be lower than HGHG by an order of magnitude

262 264 266 268 2700

0.2

0.4

0.6

0.8

1

Wavelength (nm)E

nerg

y (

mJ

(% b

w)-1

) SASE 4HGHG

x

Spectrum of HGHG and SASE at 266 nm

0.35nm

Estimation of SASE Pulse Length from Spectrum

Electron beam is ~1 ps FWHM

S. Krinsky and R.L. Gluckstern, Nucl. Instrum. Meth. A483, 57 (2002

cTb 64.0

2

ps1nm35.0m/s10364.0

)nm266(8

2

bT

HGHG Pulse Length Measurements

Two-photon absorption pump probe autocorrelation trace

1.5 2 2.5 3 3.5 4 4.5 5-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Time [PS]

Abs

orba

nce

FWHM=0.63PS

• Pulse length is 0.63 ps • Seed laser 1.8 MW• Saturation at the end of wiggler

First User Experiment in DUV-FELIon Pair Imaging Spectroscopy

F-

CH3+Molecular

BeamSource

ImagingMCPDetector

CCDCamera

Skimmer

VUV

IPIS Technique: Excitation of a molecule in the VUV/XUV accesses ion-pair states that dissociate. If one of the products is structureless (such as F-), then the kinetic energy release directly reflects the internal energy in the other product and the dynamics of the process.

CH3F*

CH3F

88 nm HGHG

CH3+-F-

K.E.R.

CH3++F-

Image

Super excited dynamics states

First User Experiment in DUV-FELFirst User Experiment in DUV-FEL

Brookhaven Science AssociatesU.S. Department of Energy

I nstallation of the first experiment – Dec, 2002Installation of the first experiment – Dec, 2002

Monochromator

Ion Pair Imaging station

Summary & Conclusions

Gain of DUV-FEL at 266 nm has been studied for various seed laser powers. HGHG FEL saturates at the middle of the 10 m long NISUS wiggler

Spectrum of HGHG is measured to be narrow compare to SASE spectrum (2.3 Å)

Output energy is measured to be stable (7% RMS) which is mainly limited by the accelerator performance

Pulse length is measured to be 0.6 - 1 ps which proves that HGHG output is temporally nearly Fourier transform limited

The 3rd harmonic (88nm) of the HGHG is used in a chemistry experiment