First Lasing of SACLA: June 7, 2011
Cheiron School 2012
Spatial profile

Pointing Stability

X-ray Free Electron Laser
Part--2: Beamline PartPart1 mm
http://xfel riken jp/information/images/mainimage jpg
http://xfel.riken.jp/information/images/mainimage.jpg

Spectrum

Makina YABASHI
1.0

Intensity / arb. unit

RIKEN SPring‐8 Center (RSC), Beamline R&D Groupyabashi@spring8.or.jp
Sep 28, 2012 @SPring‐8SASE
SR (x 100)

08
0.8
0.6
0.40.2

1

XFEL explores new worlds of science

Fundamental Science:
Create Extreme State& Energy Science:
XFEL Environmental
Probe ultrafast reactions

C ht
Coherent(100% intransverse)

11.0

11.5
Photon energy / keV

12.0

12.5

2

“Coherence
Coherence””

Brilliance(X109)

Biology & Medicine: Investigate
non-crystalline materials

0.0
10.5

Coherent Diffraction Imaging
Transverse coherenceLongitudinal coherence
Coherent radiation
Coherent light source
Incoherent scatteringg ...

Q. Do you have physical images of coherence ?

Ultrafast(~10 fs)

34

Radiation from “pointpoint”” source withmany electrons

Radiation from single electronTransverse
direction

Transverse
direction

Point source,
Many electronsin random phase(Chaotic source)

Single electron

Longitudinal
direction
Transversely coherenceLongitudinally incoherent

Transversely coherenceLongitudinally incoherent

5Coherent source

Transverse
direction

Longitudinal
direction
Transversely incoherenceLongitudinally incoherent

6

Summary

Radiation from “extended
extended”” source withmany electrons

Extended source,
Many electronsin random phase(Chaotic source)

Longitudinal
direction

Point source
Multiple electrons“seeded”-FEL
all electrons in phase“SASE”-FEL
SASE -FEL
only neighboring
electrons in phase

Extended source
Multiple electrons

78Phase retrieval with HIO (Hybrid(Hybrid‐‐Input
Input‐‐Output) method at
Courtesy of Joti-sanoversampling conditionρ′(r)ρ (r )

ΦΤInput
1. Fobs ( k )F (k )
phaseρprevious ( r ) − βρ ′ ( r )Transmission imageffrom
mid-quality
idlit
beryllium foil with voidsσL2.

ρ ′ (r )Coherent light: dangerous probe for
Reflection image of SACLA
iimperfect
f t opticsti
XFEL from double mirrors
Reflection image from with small particles
mid-quality mirror

LF ′ ( k ) = Fobs ( k ) e ( )iΦ kΦΤ -11

Hybrid Input Output (HIO) Algorism J.R. Fienup, (1982) Appl. Opt. 21, 2758‐2769

10244blank91024

Intel Xeon Nehalem W5580 : 3000 サイクル、約500

10Mirror requirement

High peak intensity

Ultraprecise surface figure is required to prevent unwanted
speckles under coherence illumination“Pulse energy”:
gy J/plsp“Peak power”: W

1st experiment of Osaka-SP8

θdPath difference: δ = 2d sinθcollaboration (Mori et al, SPIE 2001)
Plane mirror is illuminated withcoherent x-rays @ 1-km BL of SP8PPre-machined
hi dδ<λ/20, λ=0.1 nm, θ= 2.5 mradd<λ40sin θ= 1nm=00.1nm
1nm
40 × 2.5 ×10−3

EEM“Photon flux”: photons/plsEx)
Ph t flPhotonflux: 1011 photonsh t@ hν=1010 keV,k V τ=1010 fsf
11Pulse energy: I = 1.6e-19 (J/eV) x 10 x 10000 (eV)= 1.6x10
1 6x10-44 (J)= 160 uJ
Peak power: P=160 uJ/ 10 fs = 16 GW

EEM+CVM
1112

XFEL pulse can melt or ablate materials

How to use XFEL ?

Absorbed energy > melting (ablation) threshold

μ: linear absorption coeff.
coeff
ρ: density
M : average atomic weight
NA: Avogadro numberDDose((eV/atom)
V/ t )

aHigh peak power/flux in very short pulses
Can easily destroy samples after irradiation
Shot-to-shot change of pulse characterstCalculation
0 for unfocused XFEL beam
0 @SACLACu
100
Si-11
SiC
10Si
Diamond
10-2
Be
10-3

Single-shot measurement

Dosse (eV/attom)

μ IM
ρN AaEP-beam Intensity: I (# of photon per unit area)
Absorbed photon per cell: μIa2t
ρNAa2t/M
Number of atoms in cell: ρAbsorbed photon number per atom

10-402 4 6 8 10
Photon energy (keV)

13

SACLA Single-shot spectra Central energy is stable

Spike profiles change in every shot

14

Example of XFEL Beamline: SACLA
OH: Common optics& diagnostics
EH1: R&D, beam
conditioning optics

BL3

BL1

EH2: Pump & Probe (CPA/OPA)
w unfocused beamLaser booth(CPA, OPA)

EH3: Imaging/MEC
w 1-um focusing, CPA7m
EH4 O
EH4:
Open hutchh t h
XFEL-SPring-8
Exp. Facility
15

Four Experimental hutches
Basic instrumentsEH2: laser setup
EH3: 1-um focusing system
User can bring other instruments &chambers
Keeps flexibility in initial phase 16