Soft X-ray FEL

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Nov 16, 2013 (3 years and 6 months ago)

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Soft X
-
ray FEL

Project in the UK


Jon Marangos (Imperial College), Project Leader

j.marangos@imperial.ac.uk

May 2009

New directions in ultra
-
fast dynamic imaging

KEY NEW SCIENCE WE WANT TO DO:



IMAGING NANOSCALE STRUCTURES.

Instantaneous

images

of

nanoscale

objects

with

nanometre

resolution

at

any

desired

moment
.



CAPTURING

FLUCTUATING

AND

RAPIDLY

EVOLVING

SYSTEMS
.


Characterizing

the

rapid

intrinsic

evolution

and

fluctuations

in

the

positions

of

the

constituents

within

matter
.





STRUCTURAL

DYNAMICS

UNDERLYING

PHYSICAL

AND

CHEMICAL

CHANGES
.


Following

the

structural

dynamics

governing

physical,

chemical

and

biochemical

changes

by

using

laser

pump
-

X
-
ray

probe

techniques
.





ULTRA
-
FAST

DYNAMICS

IN

MULTI
-
ELECTRON

SYSTEMS
.


Capability

for

measuring

the

multi
-
electron

quantum

dynamics

that

are

present

in

all

complex

matter

* Science Case Available at www.newlightsource.org


New science enabled by an ultra
-
fast bright

light source covering THz to Soft X
-
ray range


IMAGING NANOSCALE STRUCTURES


Imaging of Isolated Objects by Coherent Diffraction
Imaging

X
-
ray pulse

Isolated

nano
-
object

Instantaneous capture
of:

Shape

Atomic Structure

Magnetic structure

Electronic properties


in Nanoscale Objects

AND

Biological Systems


< 5 fs
-

20 fs

300 eV
-

1 keV

Scattering pattern

Reconstruced image

To capture “soft” systems

like biomaterials need to

use “Diffract and Destroy”

Live unmodified picoplankton

FLASH, Hamburg March 2007

Single shot ~10 fs diffraction pattern recorded at a wavelength of 13.5 nm
of a picoplankton organism.


1 micron

Reconstructed image

DESY, Uppsala, SLAC, LLNL Collaboration

0

60

30

60

30

Resolution length (nm)

Scattering intensity

From Janos Hajdu (Uppsala)

Biological x
-
ray imaging would be extended

into water window and beyond with

prospects for 1nm feature resolution in

instantaneously recorded images

Pairs of X
-
ray pulses

Fluctuating

System


(x,y,z,t)

capture


I(Q,t)*I(Q,t +

)




CAPTURING FLUCTUATING AND RAPIDLY EVOLVING
SYSTEMS


Spontaneous dynamics in condensed matter: Correlation
Spectroscopy

Delay < 1 fs
-

100 ns

300 eV
-

>5 keV

Ultra
-
fast Bright Soft X
-
rays

Enable:


Time Resolved Holography


Ultra
-
fast XPCS

Multiple exposures

only work for “hard”

samples

STRUCTURAL DYNAMICS UNDERLYING PHYSICAL
AND CHEMICAL CHANGES




Probe changes in atomic, electronic and magnetic structure following electronic or

lattice excitation: New window into ultra
-
fast dynamics in condensed matter and

chemical reactions

New Pump
-
Probe Measurements of Structural Dynamics:

UV
-
THz short pulse pump to trigger change

Soft X
-
ray to probe

Dynamics studied by varying pump
-
probe delay


UV/IR/THz pump (including optimally shaped control pulses)


Ultrafast X
-
ray probes e.g. XAS, XPS,XES to give instantaneous
structure during chemical reactions and condensed matter
changes






Incisive structural probes such as X
-
ray
absorption will be key to this science


Photon energy range must capture the important K and L
edges, a machine with harmonics to ~7 keV is eventually
required
Revealing Electron Dynamics into Attosecond
Domain




Attosecond electron dynamics are amenable to study
through the interaction with bright short wavelength
fields.

Seeding is very important to ensure
synchronisation, high coherence and well controlled and
characterized temporal structure.


-
Probing of hole dynamics in atoms, molecules and
condensed matter in real time


-

Time
-
space resolved studies of nanoscale electron
dynamics, e.g. in nanoplasmonic structures


-
Real time probing of coherently driven processes for
optimised quantum control of matter




What New Capability Do We Need For

This New Science?



High temporal resolution pump
-
probe needs
~20fs pulses and excellent temporal
synchronization


Seeded


and so highly coherent and
synchronized


Structural methods (e.g. XAS) need multi
-
keV
photons


High peak brightness to wavelengths <1nm
needed for single
-
shot imaging techniques


High repetition rate/reproducible pulses needed
to enable a whole new range of time
-
resolved
measurements where high signal/noise is
demanded

Baseline Specification for NLS to Deliver
this Science




High brightness (>10
11

photons/pulse) in 50eV


1keV range




Harmonic radiation to 3keV (>10
8

ph/pulse) and 5keV (>10
6

ph/pulse)




Pulse duration ~20fs




Smooth wavelength scanning across entire spectral range




Synchronized to ultra
-
fast light sources covering THz
-

deep UV




1KHz repetition rate with even pulse spacing (10
-

100kHz in future)




Fully coherent X
-
rays (transverse and longitudinal)
-

seeded






Free
-
Electron Lasers

to cover the range 50 eV to 1 keV :


FEL1: 50
-

300 eV


FEL2: 250
-

850 eV

FEL3: 430
-

1000 eV

-

independently tuneable through undulator gap variation

-

variable polarization using APPLE
-
II undulators

-

seeded in order to provide longitudinal coherence, in 20 fs
pulses

-

harmonics up to 5 keV available


Conventional laser sources

+ HHG for 60 meV (20
m
洩m


50 eV


IR/THz sources
, e
-

beam generated and synchronised to
the FELs, from 20


500
m




Meeting the Baseline Specification

Bunch
compressor

BC1

Laser Heater

3
rd

Harmonic
Cavity

BC2

BC3

Collimators

EXPERIMENTAL AREA

SCRF Cryomodule #1

RF Photo
-
cathode Gun

SCRF Booster Module

FEL ‘switchyard’)

Diagnostics : Tomography

Photon Transports

Experimental Enclosures

Electron Beam Dumps

High Power Laser Gallery (1
st

floor )

Diagnostics : Deflecting Cavity

SXR Undulator Arrays

THZ/IR Undulators

Gas Harmonic Filters

Strip[ine & Kicker

5 x Dipole Arc Spreader

Beam Stop & Absorber

facility layout

CW Superconducing Linac

1kHz gun


eventually

increasing to >10 kHz

3 FELs operating

simultaneously


FEL Scheme

-

common electron energy for all 3 FELs, allows simultaneous
operation

-

seeded operation for longitudinally coherent output

-

HHG seeding with realistic laser parameters, up to 100 eV

-

harmonic cascade scheme to reach up to 1 keV


e
-

@ 2.25 GeV

Modulator 1

λ
w

= 44 mm

APPLE
-
II Radiator

λ
w

= 38.6 mm

250
-
850eV

FEL2

Modulator 2

λ
w

= 44 mm

APPLE
-
II Radiator

λ
w

= 32.2 mm

430
-

1000eV

FEL3

Modulator 1

λ
w

= 44 mm

Modulator 2

λ
w

= 44 mm

APPLE
-
II Radiator

λ
w

= 56.2 mm

50
-
300eV

FEL1

Modulator

λ
w

= 49 mm


HHG 75
-
100eV

e
-

@ 2.25 GeV


HHG 75
-
100eV

e
-

@ 2.25 GeV

HHG 50
-
100eV

1.00E+11
1.00E+12
1.00E+13
1.00E+14
0
200
400
600
800
1000
1200
# photons/pulse

Photon Energy [eV]

#Photons/pulse @ Fundamental

FEL-3
FEL-2
FEL-1
FEL Tunnel

Experimental Hall

Gun

Laser

Rooms

&

Klystron

Plant


NLS Architectural Layout

(View from Photo
-
injector end)

NLS Architectural Layout

(View from Experimental Hall end)

Module

Test

Area/

Offices

&

Control

Room

Next Steps


Complete an Outline Design for Facility


Find viable “in principle” solutions to all aspects
of the design


Develop bid to pass through STFC approval and
also gain support from other research councils


Deliver Conceptual Design Report in Autumn 09


Seek international engagement in the plan


Ask for money

NLS Science Team


Andrea Cavalleri (Hamburg/Oxford) Condensed Matter


Swapan Chattopadhyay (Cockcroft) Accelerator Concepts


Wendy Flavell (Manchester) Chemical Sciences


Louise Johnson (Diamond/Oxford) Life Sciences


Jon Marangos (Imperial) Leader / Attosecond Science


Justin Wark (Oxford) High Energy Density Science


Peter Weightman (Liverpool) Life Sciences


Jonathan Underwood (UCL) Chemical Sciences


Greg Diakun (Daresbury) Project Manager


Richard Walker (Diamond) Photon Source Manager


A large number of other scientists have contributed and are

contributing (including many from Europe, Japan and USA)

NLS Design Team


R.P. Walker,

R. Bartolini1, C. Christou, J
-
H. Han, J. Kay, I.P. Martin1, G. Rehm, J.
Rowland, Diamond Light Source, Oxfordshire, UK, 1and John Adams Institute,
University of Oxford, UK

D. Angal
-
Kalinin, J.A. Clarke, D.J. Dunning, A.R. Goulden, S.P. Jamison, K.B. Marinov,
P.A.

McIntosh, J.W. McKenzie, B.L.

Militsyn, B.D. Muratori, S.M. Pattalwar, M.W. Poole,
N.R.

Thompson, R.J. Smith, S.L. Smith, P.H. Williams, STFC/DL/ASTeC, UK

N. Bliss, M.A. Bowler, G.P.

Diakun, B.D. Fell, M.D. Roper, STFC/DL, UK

J. Collier, C. Froud, G.J. Hirst, E. Springate, STFC/RAL, UK

J.P.

Marangos, J. Tisch, Imperial College, London, UK

B.W.J. McNeil, University of Strathclyde, UK