Transcript Document

MIT X-ray Laser Project
A true x-ray laser will have enormous impact
No x-ray source is coherent
The number of photons per quantum state,
the photon degeneracy is less than 0.1
No laser has much power for l < 30 nm
Murnane and Kapteyne produced l=31nm
light pulses with a nano-Joule per pulse
X-ray Lasers: Promise to be a comprehensive probe of all spatial and
temporal scales and resolutions relevant to condensed matter
Spatial Scales
Temporal Scales
MIT X-ray Laser Project
Unique opportunity to integrate:
Accelerator technology
(MIT/Bates Lab)
Fast laser technology
(MIT Ultrafast Group)
Self-Amplified Spontaneous Emission (SASE)
SASE Radiation has full Transverse Coherence
APS Demonstrates
Self-Amplified Spontaneous Emission (SASE)
SASE Radiation is not Transform Limited
Ne / Nlc = 103
Nlc / Ne  10
3
A SASE FEL is an amplifier of electron density modulations
SASE Radiation is Powerful, But Noisy
t (fs)
Dw/w (%)
Seeding to Limit Fluctuations
DUV-FEL Facility at BNL
50 m
Copper cathode
photoinjector
Bunch
compressor
S-band linac
S-band linac
800 nm laser seed line
Modulator
undulator
Radiator
undulator
266 & 89 nm
FEL output
Buncher
30 mJ, 100 fs
Ti:Sapphire laser
Electron Beam Parameters
FEL Output Parameters
Energy
200 MeV
Max output energy
130 uJ @ 266 nm
Peak current
500 A
Max 3rd harmonic
~1 uJ @ 89 nm
RMS Emittance
3 mm-mrad
Seed input energy
100 uJ @ 800 nm
Pulse length
300 fs
RMS dE/E
0.1%
Repetition rate
5 Hz
RMS Emittance
3 mm-mrad
Pulse length
200 fs
Data from BNL DUV-FEL experiment
Bandwidth and Pulse Length
Seeded beam
SASE beam
Output
wavelength
FEL param
rFEL
Dtmin (fs) at
max BW
DEmin (meV) at
1 ps FWHM
SASE Dtmin
(fs)
SASE DEmin
(meV)
100 nm
9.e-3
20
2
100
110
10 nm
4.e-3
5
2
100
500
1 nm
1.5e-3
1
2
100
1900
0.1 nm
0.2e-3
0.8
2
100
2500
Seeded beams limited only by
uncertainty principle and seed
Df Dt 
1
2
properties.
SASE properties determined
by ebeam.
Df
f
= rFEL
MIT X-ray Laser Project
• Provide full transverse and longitudinal coherence
 get rid of the SASE noise
• Provide wide spectrum coverage: 100 nm > l <0.1 nm
 integrate the laser VUV and x-ray communities
• Implement a large number of beamlines (10-30)
 to host a large and diverse research community
 to be much more cost effective
• Produce x-ray beams that exceed 3rd Generation sources
 in flux and brilliance
 in peak flux and peak brilliance
 and therefore, in coherence and photon degeneracy
MIT X-ray Laser Project
How to reach wavelengths below 1 nm?
• Must get the shortest wavelength seeds
using High Harmonic Generation methods,
--30nm available now, possible 10 nm or below
• Then use “cascaded” High Gain
Harmonic Generation methods in FEL,
--factors of >30 are possible
MIT Ultra-fast Group—HHG seeding methods
J. Fujimoto, H. Haus, E. Ippen, F. Kaertner
x-ray harmonic
emission
=
=/
-4
-2
0
Time, fs
See current issue of Physics Today
2
4
High-Harmonic Generation
Noble Gas Jet (He, Ne, Ar, Kr)
100 mJ - 1 mJ
XUV @ 3 – 30 nm
@ 800 nm
h = 10-8 - 10-5
t
Propagation
Recombination
0
tb
Ionization
Energy
-Wb
wXUV
Laser electric field
x
High Gain Harmonic Generation
Method to reach short wavelength FEL output from longer
wavelength input seed laser.
Input seed at w0
overlaps electron
beam in energy
modulator undulator.
Modulator is tuned to
w0.
Electron beam
develops energy
modulation at w0.
Energy modulation is
converted to spatial
bunching in chicane
magnets.
3rd harmonic
bunching is
optimized in
chicane.
Electron beam radiates
coherently at w3 in long
radiator undulator.
Radiator is tuned to w3.
Cascaded HGHG
Output at 3w0
Output at 9w0
Final output
seeds 2nd stage
seeds 3rd stage
at 27w0
Input
seed w0
1st stage
2nd stage
3rd stage
•Number of stages and harmonic of each to be optimized during study.
•Factor of 10 – 30 in wavelength is reasonable without additional
acceleration between stages.
•Seed longer wavelength (100 – 10 nm) beamlines with ~200 nm harmonic
from synchronized Ti:Sapp laser.
•Seed shorter wavelength (10 – 0.3 nm) beamlines with HHG pulses.
Laser System & Synchronization
Fiberlink + Synchronization
Photo-Injector:
~200 m
1-10 ps Pulses
High Harmonic
Generation
1 nJ – 10 nJ
1-10 mJ
100 as – 10 ps
1-20 kHz
1-20 kHz
@ 266 nm
(conv. NLO)
@ 1 - 30 nm
10 fs
Timing Jitter
E-beam
LINAC
FEL
Output: Three highly synchronized pulse streams
E-beam, EUV 1 - 30 nm and @ 800 nm driver pulse
MIT X-ray Laser Concept
Main oscillator
Seed
laser
UV Hall
Fiber link synchronization
Pump
laser
Seed
laser
X-ray Hall
Pump
laser
Undulators
100 nm
Injector
laser
30 nm
Undulators
1 nm
10 nm
0.3 nm
0.3 nm
SC Linac
1 GeV
2 GeV
SC Linac
0.1 nm
4 GeV
10 nm
Upgrade: 0.1 nm
at 8 GeV
3 nm
1 nm
Undulators
Seed
laser
Nanometer Hall
Pump
laser
Nanometer Hall
to master oscillator for timing sync
Direct seeded or cascaded
HGHG undulators
10 nm
Ti:Sapp + BBO = 200
nm seed
Ti:Sapp + HHG = 10-30 nm seed
Tune by OPA or harmonic number
Seed
lasers
~20 m length
10 GW peak
Cascaded HGHG undulators
3 nm
Cascaded HGHG undulators
Ti:Sapp + HHG = 10-30 nm seed
1 nm
Tune by OPA or harmonic number
~30 m length
4 GW peak
Pump
lasers
Pulse Structure (Quasi-CW)
RF Gun Pulse
-10
0
10
Time (us)
~90 Warm RF Gun Pulses
0.1% Duty Factor
8 Pulses
8 Beamlines
~500 pC / Pulse
1 us spacing 20
1 ms spacing
0
100
Time (ms)
SC Linac Pulse
0
500
@1Hz
1000
1500
Time (ms)
10% Duty Factor
2000
2500
Seeding for short pulse
Output time profile
Time profile (log plot)
10
2
8
1.5
10
1
0.5
1
0
24.5
1000
25
25.5
26
Time (fs)
26.5
Power (kW/bin)
1.5
10
Power (W)
Power (GW)
Power (GW)
2
6
10
4
10
27
2
10
0.5
0
10
20
30
Time (fs)
40
50
GINGER simulation of
seeded FEL at 0.3 nm.
Same ebeam parameters as SASE case.
800
600
400
200
0
10
0
Spectrum
0
10
20
30
Time (fs)
40
Seed laser parameters
FWHM
Power
Pulse energy
0.5 fs
10.0 MW
5 nJ
50
0
0.2995
0.3
0.3005
Wavelength (nm)
FEL output parameters
Saturation FWHM
Saturation power
Saturation energy
0.75 fs
~2.0 GW
1.5 mJ
FWHM linewidth
6.0E-4
Undulator length
20 m
0.301
Seeding for narrow linewidth
Output time profile
10
2
10
1.5
10
500
1
Power (MW/bin)
Power (W)
8
Power (GW)
Spectrum
Time profile (log plot)
6
10
4
10
0.5
2
0
0
10
20
30
40
50
10
Time (fs)
GINGER simulation of
seeded FEL at 0.3 nm.
Same ebeam parameters as SASE case.
300
200
100
10
0
400
0
10
20
30
Time (fs)
40
50
0.3
0.3005
0.301
Wavelength (nm)
Seed laser parameters
FWHM
Power
Pulse energy
0
0.2995
50 fs
0.1 MW
5 nJ
FEL output parameters
Saturation FWHM
Saturation power
Saturation energy
30 fs
~2.0 GW
0.1 mJ
FWHM linewidth
1.0E-5
Saturation length
28 m
Comparison of SASE and Seeded Sources with APS Undulator A
Cost Basis
• Fixed Costs
80 M$
(Gun, X-ray Beamlines, Buildings, Cryoplant, Controls…)
• Linac Systems (20 MeV/m, ~0.4M$/m)
• Undulator Systems (0.2 M$/m)
20M$/100m
20 M$/GeV
Total Undulator Length = 4 x longest saturation length
• Contingency
25%
Example
• 4 GeV Linac
• 50 m Saturation Length
Costs:
80 M$
80 M$
40 M$
50 M$
-----------250 M$
Fixed
Linac
Undulators
Contingency
Total
Saturation Length (m)
1000
100
10
1
0
5
10
Electron Energy (GeV)
15
20
Saturation Length (m)
1000
λu = 18 mm
λu = 23 mm
λu = 30 mm
0.1 nm
100
0.15 nm (LCLS)
0.3 nm
1 nm
10
10 nm
100 nm
1
0
5
Hybrid Undulator Parameters
VISA:
λ = 18 mm, K=1.4, B=0.8 T
23mm: λ = 23 mm, K=2.4, B=1.1 T
LCLS: λ = 30 mm, K=3.9, B=1.4 T
10
Electron Energy (GeV)
15
20
Electron Bunch Parameters
Q = 0.5 nC ΔE/E = 0.02% T = 250 fs
ε = 1.5 μm
Better Gun
ε = 0.75 μm
Superconducting Undulator
λ = 14 mm K = 1.3
1000
Hybrid Undulator Parameters
VISA:
λ = 18 mm, K=1.4, B=0.8 T
23mm: λ = 23 mm, K=2.4, B=1.1 T
LCLS: λ = 30 mm, K=3.9, B=1.4 T
Saturation Length (m)
0.1 nm
0.3 nm
100
1 nm
10
10 nm
100 nm
1
0
Superconducting Undulator
“Miracle Gun”
ε = 0.1 μm
5
10
Electron Energy (GeV)
15
20
Electron Bunch Parameters
Q = 0.5 nC ΔE/E = 0.02% T = 250 fs
ε = 1.5 μm
Essential to Improve e-Gun Performance
•In linacs, electron emittances scale inversely with energy
•Electron beam emittance is born at the electron gun
•Electron gun emittances today are ee = 0 .5 nm / E (GeV)
•Photon emittances for full transverse coherence ep = lp /4
To couple a given electron beam most effectively to a
coherent photon field, we should have:
ee = ep
MIT X-ray Laser Concept
Main oscillator
Seed
laser
UV Hall
Fiber link synchronization
Pump
laser
Seed
laser
X-ray Hall
Pump
laser
Undulators
100 nm
Injector
laser
30 nm
Undulators
1 nm
10 nm
0.3 nm
0.3 nm
SC Linac
1 GeV
2 GeV
SC Linac
0.1 nm
4 GeV
10 nm
Upgrade: 0.1 nm
at 8 GeV
3 nm
1 nm
Undulators
Seed
laser
Nanometer Hall
Pump
laser
The MIT X-ray Laser Project
MIT/ Bates Laboratory
•A National User Facility: 10-30 beams
•Wavelength range 100-0.1 nm
•Integrated laser seeding for full coherence
•Pulses: Dt=1-1000 fs; Dw=3-0.003eV
•Pulse power of up to 1 mJ
•Pulse rates of 1 kHz or greater
Science: single molecule imaging, femtochemistry, nanometer lithography…
Technology: superconducting FEL, Ti:Sapp HHG seeding technology
Education: accelerator science curriculum, synergy with CMSE programs
Cost/Schedule: $300M; design: FY04-FY06; construct: FY07-FY10
MIT Commitment
• MIT has embraced the x-ray laser concept
exclusively for the future of Bates Laboratory
• Deans of Science and Engineering and the VP of
Research provided over $400K in seed support
• President Vest asked a key CEO to chair a
corporation-level advisory committee to secure
support of business and political leaders in MA
Charge to
MIT X-ray Laser
Accelerator Science Advisory Committee
September 18-19, 2003
The proposed MIT x-ray laser facility is at an early stage of
conceptual design. The goals of the design are to produce fully
coherent x-ray pulses with the stable and reliable operations
required of a user facility. We seek guidance and constructive
criticism regarding the technical choices that are being made.
The ASAC committee should:
•Review laser and accelerator sections of proposal to NSF and
technical presentations at committee meeting.
•Evaluate the appropriateness of chosen technologies and suggest
alternatives.
•Identify the primary technical challenges for each system and for
the facility as a whole.
•Respond to NSF reviewer comments.
Evaluate the potential for a facility based on the Bates linac to
demonstrate laser seeding and cascaded HGHG, and selected
scientific applications
MIT X-ray Laser Design Proposal
3-year duration, $15M total request
Contact: David E. Moncton, Director
Telephone: 617-253-83333
E-mail: [email protected]
website: http://mitbates.mit.edu/xfel/indexpass.htm
Co-Principal Investigators
William S. Graves
Franz X. Kaertner
Richard Milner
Science Collaborators
Simon Mochrie
Gregory Petsko
Henry I. Smith
Bates Senior Staff
Manouchehr Farkhondeh
Jan van der Laan
Christoph Tschalaer
Fuhua Wang
Abbi Zolfaghari
Townsend Zwart
Keith A. Nelson
Dagmar Ringe
Andrei Tokmakoff
Contributors
William M. Fawley
Hermann Haus
Ian McNulty
Jianwei Miao
Mark Schattenburg
James Fujimoto
Erich Ippen
Denis B. McWhan
Michael Pellin
Gopal K. Shenoy
Existing Technology
Electron Guns
Adequate performance has been demonstrated.
Room for continuing R&D and improvement.
Not a cost driver.
Existing Technology
Linac
Successful operation at Tesla Test Facility, JLAB.
Capital cost driver.
Existing Technology
Undulator
Well established. Successful experience at LEUTL, TTF.
Make use of investment in LCLS design.
Capital Cost driver.
3-year study plan