Applications of Intense CSR from a cw Linac at Jefferson LabGwyn P. Williams, Mike Klopf & the JLab TeamJefferson Lab
12000 Jefferson Avenue
Newport News, Virgnia 23606

UVSOR Workshop on Terahertz Coherent
Synchrotron Radiation September 23-25, 2007

Introduction to the Jefferson Lab CSR THz Source

Source Characteristics• 1 microJoule per pulse, 75 MHz, 180 fs FWHM
10 MW peak, 100 Watt average power•

Achieved using superconducting linac with cw rf

Overview of the CSR THz Programs at Jefferson Lab• Tissue interactions and safety limits.
• Imaging.
• Spectroscopy development – signal to noise etc..
⇒ magnetism, dynamics of quasiparticles, spin
⇒ localization effects
Future• Electro-optical detection• Quantum coherence and control.
• Coherent Half- and Few-Cycle Sources for Nonlinear
and Non-Equilibrium Studies.

Jefferson Lab - where are we?

Brookhaven LabJefferson Lab

Jefferson Lab, Newport News, VA
Home of 2 accelerators: each withsuperconducting linacs, photo-cathode gunsFEL

sc linacs
photo-guns

JLab Free Electron Laser facility

135 pC per bunch = 1 µJ
Pulse FWHM 200fs – 2 ps75 MHz

All sources are simultaneouslyproduced for pump-probe studies

75 MHz – achievable using superconducting
linac in energy recovery mode

RGA, extractor gauge
and leak valve

Electrodes
Vacuum chamber

Ceramic stand -offs

Photocathoderetractor
mechanism

SolenoidSuperconducting
linac cavity

Corona shield

PhotocathodeHigh voltage feed

NEG pumps
33 inches

GunJefferson Lab Facility Spectroscopic Range and Power
Energy (meV)
1

10

100

1000

10000
1000
100

JLab THz-1

Flux (Watts/cm )10

JLab FEL

10.1

Table-top sub-pslasers

0.01
1E-3
1E-4

onsrtorhcnyS

1E-51E-6
1E-7raob

1E-8l
G
THz proof of principle:

1E-9
1E-10

Carr, Martin, McKinney, Neil, Jordan & Williams
Nature 420, 153 (2002)

1E-11
1E-12
1101001000-1Wavenumbers (cm )10000

FEL proof of principle:
Neil et al. Phys.
Rev.Letts 84, 662(2000)

Coherent Synchrotron Radiation Generation - theory
Jackson, Classical Electrodynamics, Wiley, NY 1975

Near-field term not normallyconsidered for synchrotron calculations

Electric field for single particle:-rrrrrr&r−1γ −2 (n − β )n×[(n−β)×β]+cR
1−eee exp[iω (τ + R / c)]dτr
Eω = ec ∫r 2(1− n βe ) R−∞+∞REFERENCES

R.A. Bosch, Nuclear Instr. & Methods A431 320 (1999).
O. Chubar, P. Elleaume, "Accurate And Efficient Computation Of Synchrotron Radiation In
The Near Field Region", proc. of the EPAC98 Conference, 22-26 June 1998, p.1177-1179.

Coherent Synchrotron Radiation Generation - theoryd 2 I = ⎡⎢ N[1 − f ( ω )] + N 2 f ( ω )⎤⎥ × ⎡ single particle intensity ⎤⎢⎥⎥⎦ ⎣⎦dω d Ω ⎢⎣f(ω) is the form factor – the Fourier transform of the normalized longitudinal
particle distribution within the bunch, S(z)r∞⋅ωinzf ω = ∫ e ˆ /cS ⎛⎜⎜ z ⎞⎟⎟ dz⎝ ⎠−∞⎛⎜⎜⎝⎞⎟⎟⎠

2Larry CarrdE≈ 2 × 10 − 25 J/cm-1/electrondν

REFERENCES
S.L. Hulbert and G.P. Williams, Handbook of Optics: Classical, Vision, and X-Ray Optics,
2nd ed., vol. III. Bass, Michael, Enoch, Jay M., Van Stryland, Eric W. and Wolfe William L.
(eds.). New York: McGraw-Hill, 32.1-32.20 (2001).
S. Nodvick and D.S. Saxon, Suppression of coherent radiation by electrons in a synchrotron.
Physical Review 96, 180-184 (1954).
Carol J. Hirschmugl, Michael Sagurton and Gwyn P. Williams, Multiparticle Coherence
Calculations for Synchrotron Radiation Emission, Physical Review A44, 1316, (1991).

JLab THz Beam Schematic with Optical Beam Ray-tracing
31.021M4F3

Vertical Position

Vertical Position

0.5

00.0-1-2-0.5-2-3x10 m-30mm

60x60mm-20-100102030

Horizontal Position

3-1-1.0x10 m-100mm

-50

050

100200x200mm2Horizontal Position

F21
Vertical Position

1.00-10.560x60mm-3x10 m-30mm

0.0-20-100102030

Horizontal Position

M2-0.5-1-1.0x10 m-100mm-50050100200x200mm

200x200mm
Horizontal Position

4M12
Vertical Position

Vertical Position-2-20-2-2-4x10 m-40mm-200Horizontal Position

2040

JLab THz Beam Pattern on Mirror 1

Vertical Position

Vertical Position

20-24220-2-4x10 m

4

Vertical Position

4-2-2-4x10 m-4x10 m-2-2-40mm-20020040-40mm-20Horizontal Position

02040-40mm-20Horizontal Position

2040

Horizontal Position

1 THz
33 cm-10.1 THz
3.3 cm-1010 THz
330 cm-1
96140x10

2.0x106800x10

100
80
60
40

2

Phot/s/0.1%bw/mm

Phot/s/0.1%bw/mm

2

Phot/s/0.1%bw/mm

2120

600

400

200

1.5

1.00.520-40mm-20

0
Horizontal Position

2040-40mm-200Horizontal Position

2040-40mm-200
Horizontal Position2040

Jefferson Lab THz spectra and total power
Frequency (THz)
0.1110100000
10000
1000
10010Watts/cm-110.154 W540 W

840 W

0.01
1E-3

100 MHz 100 pC
150 x 150 mr
0.1 ps0.3 ps1.0 ps

1E-4
1E-5
1E-6
1E-7
1E-8
1E-9
1E-10
110100-1

Frequency (cm )1000

JLab Terahertz Beam Extraction and Transport

M2
M3
diamondwindow
M1

Shutter/viewer &camera

V1
M1

Mirror 1 - courtesy of Richard Wylde, (Thomas Keating)Thomas Jefferson National Accelerator Facility
Operated by the Southeastern Universities Research Association for the U.S. Department of Energy

JLab power permits large area imaging ~ m2

10mm2Ray trace

Optical transport output in User Lab
Real time image
Thomas Jefferson National Accelerator Facility
Operated by the Southeastern Universities Research Association for the U.S. Department of Energy

Challenges of Stand-off THz Imaging• Providing sufficient THz power to illuminate a large
field of view and to image in real time
• Properly collecting the scattered THz radiation fromthe target region (transmission mode generally notuseful)• Filtering of the THz induced thermal IR• Properly imaging onto a detector array• Creating imaging arrays designed specifically for THzimaging

Imaging / bio-medical cancer screening

Basal cell carcinoma shows malignancy in red. Teraview Ltd.
1 mW source images 1 cm2 in 1 minute
100 W source images whole body (50 x 200cm) in few seconds

Imaging / security screening at portals

Clery, Science 297 763 (2002)
Spectra of explosives
courtesy of Teraview

Jefferson Lab & U. of Delaware TeamTHz Imaging Schematic

beamline

visiblecameraTHz filter/lensmirror 2
mirror 1
THz camera

mirror 3

objectmoves/rotates

2 Watts of broadband light onto 75mm x 75mm field.
~104 camera elements, so 200 microWatts per pixel.
Scattering ~ 0.1%, so 0.2 microWatts per pixel.
Noise level, 1 nanoWatt, so S/N is ~200.

The Camera

http://www.corebyindigo.com/PDF/TVMicron.pdf

THz Imaging Layout

THz Induced Thermal IR
BeamDataONRaw

paper target

BeamOFF Data
Processed

imaging target

paper target

imaging target• Images taken using the stock Ge lens
• THz passes through paper target and is reflected off of theimaging target• Heating due to absorption of THz heats the paper and theimaging target, producing the thermal IR seen above

Test Pattern Imaging Target

Test of Imaging Resolution
Processed Data35 mm
•••

26 mm

26 mm

Raw Data

35 mm

Raw THz images are processed to reduce the background andimprove contrast
Current configuration resolved down to the 1mm wide contact pads
Polyethylene lens filtered the thermal IR, but does not image wellTHz Imaging Covered Target
Raw Data

CD mailer covering

Processed Data

cloth covering

4. THz effects

Duke U. - tune to intramolecular bonds to eliminate collateral damage

Human Effects, contd. - Jill McQuade• Many applications for THz sources• High-power sources and detectors are being developed• Bioeffects need to be understood for the health and safetyof personnel• Bioeffects efforts need to catch up to or even leadtechnology development• Bioeffects data pertaining to the health effects of highpowered THz exposure are non-existentBrooks Air Force Base – Human Effects Division,Terahertz TeamDr. Jill McQuade

HEDR

Physiologist: Project Lead

Dr. Bob Thomas

HEDO

Physicist: Modeling

Mr. Jason Payne

HEDR

Biomedical Scientist:
Modeling

Ms. Nichole Jindra

HEDO

Biologist: Expt, pilot lead

Dr. Semih Kumru

HEDO

Physicist: Expt

Mr. Victor VillavicencioHEDO-NG Cont

Physicist: Expt

Dr. Ron Seaman

HEDR–GD-AIES Cont

Physiologist: Expt, protocol

Mr. Alex Salazar

HEDR–GD-AIES Cont

Physiologist: Expt

Dr. Walter Hubert

HEDR

Molecular Biologist:
Biotechnology

Brooks Terahertz Experiments & Modeling
Performed at Jefferson Laboratory
Experimental Validation of models– characterization of the beam
– exposures of wet chamois, 2 phantoms••

ED50 (2 s exposure) chamois = 7.14 W/cm2
Model predicted 4-5 W/cm260

50T em perature R ise (C )

••

4030

2010002468102Irradiance (W/cm )121416

Laboratory layout for spectroscopy & pump-probe

Measured JLab – FEL THz Spectrum in Air-1

Wavenumber (cm )
020

40

60

80

100

120

1400.30

0.30

JLab - FEL THz spectrum
τ p ~ 350 fs

Intensity (arb. units)

0.25

0.25

0.20

0.20

0.15

0.15

0.10

0.10

0.05

0.05

0.00

0.00
01

2

3THz

4

Early IRSR experiments
GLOBARN2O

SYNCHROTRON!
>10x worse!!

BESSY 1 1985-86
Schweitzer, Nagel, Brain, Lippert and Bradshaw Nucl. Instr. & Methods A246 163 (1986)

Experimentation Issues – NSLS Signal to Noise
dynamic range 1000 in 1 sec.

with Larry Carr

Experimentation Issues – FEL Signal to Noise

dynamic range 50 in 1 sec.

Shear Interferometer – Sievers and Agladze, Cornell

linear arraypath differenceTHz HFTS during experiments at Jefferson Lab FELCoherent synchrotron radiation measurements
Interferograms

Calculated spectraSome of the JLab Team

Photo taken Jan 16, 2007

This work supported by the Office of Naval Research, the Joint Technology
Office, the Commonwealth of Virginia, the Air Force Research Laboratory, TheUS Army Night Vision Lab, and by DOE under contract DE-AC05-060R23177.

Jefferson Lab Facility Spectroscopic Range and Power
Energy (meV)
110100

1000

10000
1000
100

JLab THz-1

Flux (Watts/cm )10JLab FEL

10.1

Table-top sub-pslasers

0.01
1E-3
1E-4

ons
rtor
hcny
S

1E-5
1E-6
1E-7

raob

1E-8l
GTHz proof of principle:

1E-9
1E-10

Carr, Martin, McKinney, Neil, Jordan & Williams
Nature 420, 153 (2002)

1E-11
1E-12
1101001000-1

Wavenumbers (cm )10000

FEL proof of principle:
Neil et al. Phys.
Rev.Letts 84, 662(2000)

Conclusions•

We have a high power CSR THz source capable of illuminating alarge field of view which can be imaged at full video rates•

Initial results have resolved features down to 1mm•

Filtering of the thermal IR is necessary to utilize the important
properties of THz radiation•

Development of compact high power THz source will enable deployedsystems (Advanced Energy Systems)•

We have a user program in place to look at biological effects•

We have just started our spectroscopy programs

Some of the JLab Team

Photo taken Jan 16, 2007

This work supported by the Office of Naval Research, the Joint Technology
Office, the Commonwealth of Virginia, the Air Force Research Laboratory, The
US Army Night Vision Lab, and by DOE under contract DE-AC05-060R23177.

EXTRA SLIDESExample of niche of 4th. Generation → Si:H
Defect Dynamics

Luepke et al. CWM/Vanderbilt

0

H2*

IH2-1
Ln[Sb]

(+)
HBC

V2H

VH2

VH4

Luepke et al. Phys. Rev. Letts 85, 1452 2000
Wm. & Mary Phys. Rev. Letts 88, 135501, 2002
Vanderbilt Phys. Rev. Letts 87, 145501, 2001
Phys. Rev. B63 195203 2001
J. Appl. Phys. 93 2316, 2003(+)
HBC-2-301020Time delay (ps)T1 = 7.8 ± 0.2 psExperimentation Issues
NSLS Beam on, modulation on
NSLS Beam on, modulation off
NSLS Beam off, mod. off
JLab Beam off, mod. off
JLab Beam on, modulation off
JLab Beam on, modulation on-40dB(u)-60-80

Source Chop (ω) Detector-100
NSLS Beamline U12IR
1.8K Bolometer Bruker 125
12mm aperture, no sample
600 mA beam current-120020406080

100120140

Frequency (Hz)160180200220240

Concluding Remarks•Over the past 10 years Jefferson Lab has constructed and commissioned anext generation light source based on an Energy Recovered Linac.

•Our experience with generating ultrafast electron beams and diagnostics,
can help implementation of Cornell ERL.

•This ERL, or an x-ray ERL yielding THz light could have a huge impact onhigh pressure research.

Summary• Tremendous opportunities• In class of our own• Must stay at scientific frontiers• Great local university teams• Helping Florida State, Cornell, Daresbury andother 4th. generation light source facilities
This work supported by the Office of Naval Research, the Joint Technology
Office, the Commonwealth of Virginia, the Air Force Research Laboratory, The
US Army Night Vision Lab, and by DOE under contract DE-AC05-060R23177.

Daresbury data holds world record!!
Globar CO/Pt
3 days!! 105 secs

Synchrotron
SnCl4/silica
Daresbury 1998
200 secs

Engstrom and Ryberg,
J. Chem. Phys. 115 519 (2001)
Paul Dumas and collaborators- many papers

Pilling, Gardner, Pemble and Surman, Surf. Sci. 418 L1 (1998)

JLab FEL Drive Laser Noise

Amplitude (arb. units)

Michelle Shinn

0200400600

800 1000 1200 1400 1600

Frequency (Hz)Comparing Conventional THz Sources andCoherent THz Synchrotron

2e a 4
Larmor's Formula: Power =γ (cgs units)
33c2 2a=acceleration
c=vel. of light
γ=mass/rest masse- -> 40 MeV~100 VTHz
GaAsfsec
laserpulse

100V
E = −4 = 10 6 V
m10 m
F
10 6 V
10 6 ( 3 × 10 8 )2=a= =2m .5MeV / c
0.5 × 10 6
≅ 10 17 m
sec 2fsec
laserpulse

ρTHz

GaAsc 2 ( 3 × 10 8 )2a==≅ 10 17 m
sec 2
ρ1if ρ = 1 m

γ = 200 and 2004 = 109 !!!!

Synchrotron Radiation Generation - 2 time-scales
Statistics of an electron bunch in a storage ring

T1

T2 - Time Scale for Coherent Synchrotron Radiation

Hirschmugl, Sagurton and Williams, Physical Review A44, 1316, (1991).

Coherent Synchrotron Radiation Generation

Electric field

E/NtimeIntensity ⏐E2 ⏐electron(s)5∆t = 12 cργ =≈0.25 Attoseconds
38γ
4000 × 3×10

Nsuper-radiantenhancement

freq. (1/time)Multiparticle coherence – Free Electron Laser

Hirschmugl, Sagurton and Williams, Physical Review A44, 1316, (1991).

Spectrum of uric acidat 0.5 cm-1 spectral resolution Recorded at SFTC Daresbury

277 cm-1
163 cm-1

297 cm-1

144 cm-1
133 cm-1

48 cm-1
215 cm-1

80 cm-1

Schematic of JLab 4th. Gen. Light Source Operation
Niobium SRF Cavity withOscillating Electromagnetic Field
Electron Beam
Drive Laser

Cryomodule

Light Output

Injector

GunBeam Stop

Wiggler
Total Reflector

Output Mirror
Periodic Magnetic Field
Electron Beam

Laser Wavelength ~ Wiggler wavelength/(2Energy)2

Experimentation Issues
NSLS Beam on, modulation on
NSLS Beam on, modulation off
NSLS Beam off, mod. off
JLab Beam off, mod. off
JLab Beam on, modulation off
JLab Beam on, modulation on-40dB(u)-60-80

Source Chop (ω) Detector-100
NSLS Beamline U12IR
1.8K Bolometer Bruker 125
12mm aperture, no sample
600 mA beam current-120020406080

100120140

Frequency (Hz)160180200220240

Generic Light Source Landscape – Average Brightness
30

Photons/sec/0.1%BW/mm /milliradian

21x10

281026

Electron Beam Energy = 3 GeV
Bending Radius = 5m
1 nc @ 100 MHz (100 mA)

21x102410RLA2210MLRO4GLS 1x1nm
10(x10 for multiparticle)

TIM I

20103GLS 10 x 500 microns(x500 for ID)

1810161014101210

2GLS 500x1000 microns

1010810610410
1E-4

1E-30.01

0.1

110Photon Energy (eV)

100

1000

10000

Gwyn Williams - file brt_1.bas
May 25, 2006

General Landscape – Light Source “Generations”

1st. Generation – parasitic use of nuclear and high energy physics machines
2nd. Generation – dedicated storage rings – higher current, lower emittance3rd. Generation – storage rings with insertion devices (wigglers), loweremittance4th. Generation – typically linac based, lower emittance, multiparticle
coherence

Generic Light Source Landscape – Average Brightness
30

Photons/sec/0.1%BW/mm /milliradian

21x10281026

Electron Beam Energy = 3 GeV
Bending Radius = 5m
1 nc @ 100 MHz (100 mA)

21x10

L
R
O

24

LS
M
G4R
L
L
LA
E
FE
VFU
B
A
S
JL3GLS
Lmicrons
10 x 500
G(x500 for 4ID)

10221020

1018101610144GLS 1x1nm
10(x10 for multiparticle)

T
IM I

LSCL

EL
FX

HzTU
B
S
A
FJL

1012102GLS 500x1000 microns

10108106104101E-4

1E-30.010.1

110Photon Energy (eV)1001000

10000

Gwyn Williams - file brt_1.bas
May 25, 2006

Generic Light Source Landscape – Peak Brightness3610341x1032

1x10301028

1x1026102410221020101810161014101210102

Photons/sec/0.1%BW/mm /milliradian

21x1010Electron Beam Energy = 3 GeV
Bending Radius = 5m
1 nc @ 100 MHz (100 mA)
MULTIPARTICLE ENHANCEMENT
4GLS 1x1nm 50fs FWHM
10(x10 for multiparticle)

ITM
ILRMORLA

INSERTION DEVICE
3GLS 10 x 500 microns(x500 for ID) 50ps FWHMDIPOLE
2GLS 500x1000 microns
500 ps FWHM

81E-4

1E-30.010.1

110

Photon Energy (eV)1001000

10000

Gwyn Williams - file brt_1.bas
May 25, 2006

Generic Light Source Landscape – Peak Brightness
36

1x10

Photons/sec/0.1%BW/mm /milliradian

21034
32

1x10Electron Beam Energy = 3 GeV
Bending Radius = 5m
1 nc @ 100 MHz (100 mA)

30

1x10

210ITM
ILRMO
ABL
RJ
LA

28
26

1x101024102210201018101610141012101010LSCLLELFHXS
AFL

MULTIPARTICLE
ENHANCEMENTFE
VU
4GLS 1x1nm 50fs FWHM
10LS
4G (x10 for multiparticle)

HzTUB
S
AF
L
J

INSERTION DEVICE
3GLS 10 x 500 microns(x500 for ID) 50ps FWHMDIPOLE
2GLS 500x1000 microns
500 ps FWHM

81E-4

1E-3

0.01

0.1

110

Photon Energy (eV)100100010000

Gwyn Williams - file brt_1.bas
May 25, 2006

First CSR Science:
Josephson Plasma Resonance in
Bi2Sr2CaCu2O8
Data from Nov. 2002

+ Indications for inhomogeneous
superfluid
M. Abo-Bakr et al. Phys. Rev. B 69 (9),092512 (2004).

λc = 21 µm

Non-linear dynamical effects using high field THz light

High electric fields are predicted
to generate localized modes!

A biopolymer chain buckles and folds on itself due to an instability produced by anonlinear localized mode – Physics Today Jan. 2004 p43.
Mingaleev et al Europhys. Lett. 59 403 (2002)
JLab collaboration with Al Sievers, Cornell U.