Gwyn P. Williams, Mike Klopf & the JLab Team Jefferson Lab - - PowerPoint PPT Presentation

Gwyn P. Williams, Mike Klopf & the JLab Team Jefferson Lab 12000 Jefferson Avenue Newport News, Virgnia 23606

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

Applications of Intense CSR from a Applications of Intense CSR from a cw cw Linac Linac at Jefferson Lab at Jefferson Lab

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

Jefferson Lab - where are we?

Brookhaven Lab

Jefferson Lab, Newport News, VA

FEL sc linacs photo-guns Home of 2 accelerators: each with superconducting linacs, photo-cathode guns

JLab Free Electron Laser facility

All sources are simultaneously produced for pump-probe studies

135 pC per bunch = 1 µJ Pulse FWHM 200fs – 2 ps 75 MHz 75 MHz – achievable using superconducting linac in energy recovery mode

Electrodes Vacuum chamber Ceramic stand -offs Corona shield High voltage feed NEG pumps RGA, extractor gauge and leak valve Photocathode Photocathode retractor mechanism 33 inches Electrodes Vacuum chamber Ceramic stand -offs Corona shield High voltage feed NEG pumps RGA, extractor gauge and leak valve Photocathode Photocathode retractor mechanism 33 inches Solenoid

Gun Superconducting linac cavity

1 10 100 1000 10000 1E-12 1E-11 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1 1 10 100 1000 10000

Energy (meV) Flux (Watts/cm

• 1)

Wavenumbers (cm

• 1)

1 10 100 1000

JLab THz S y n c h r

• t

r

• n

s G l

• b

a r JLab FEL Table-top sub-ps lasers Jefferson Lab Facility Spectroscopic Range and Power

FEL proof of principle: Neil et al. Phys. Rev.Letts 84, 662 (2000) THz proof of principle: Carr, Martin, McKinney, Neil, Jordan & Williams Nature 420, 153 (2002)

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 - theory

REFERENCES 1 2 1 2

[( ) ] ( ) exp[ / )] (1 )

(

e e e e

n n cR n E ec i R c d n R

ω

β β γ β ω τ β

τ

+∞ − − − −∞

× − × + − = + −

∫

r r r r r r & r r r

Jackson, Classical Electrodynamics, Wiley, NY 1975 Electric field for single particle:-

Near-field term not normally considered for synchrotron calculations

2 / ˆ i n z c

f e S z dz

ω

ω

⎛ ⎞ ⎛ ⎞ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠

∞ ⋅ −∞

=∫

r

2 2

N[1 f ( )] N f d I single particle in ( tens ) ity d d ω ω ω Ω

⎡ ⎤ ⎢ ⎥ ⎢ ⎥ ⎡ ⎤ ⎣ ⎢ ⎥ ⎦ ⎦ ⎣

= × − +

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).

Coherent Synchrotron Radiation Generation - theory

f(ω) is the form factor – the Fourier transform of the normalized longitudinal particle distribution within the bunch, S(z)

REFERENCES

25

10 2

−

× ≈ ν d dE J/cm-1/electron

Larry Carr

JLab THz Beam Schematic with Optical Beam Ray-tracing M1

• 4x10
• 2 m
• 2

2 4 Vertical Position

• 40mm
• 20

20 40 Horizontal Position

200x200mm

• 3x10-2 m
• 2
• 1

• 30mm
• 20
• 10

60x60mm

F2

• 1.0x10-1 m
• 0.5

0.0 0.5 1.0 Vertical Position

• 100mm
• 50

50 100 Horizontal Position

200x200mm

M2

• 1.0x10
• 1 m
• 0.5

• 100mm
• 50

200x200mm

M4 F3

• 3x10
• 2 m
• 2
• 1

• 30mm
• 20
• 10

60x60mm

10 THz 330 cm-1

• 4x10
• 2 m
• 2

2 4 Vertical Position

• 40mm
• 20

20 40 Horizontal Position

1 THz 33 cm-1

2.0x109 1.5 1.0 0.5 Phot/s/0.1%bw/mm

2

• 40mm
• 20

20 40 Horizontal Position

• 4x10
• 2 m
• 2

2 4 Vertical Position

• 40mm
• 20

20 40 Horizontal Position

800x10

6

600 400 200 Phot/s/0.1%bw/mm

2

• 40mm
• 20

20 40 Horizontal Position

• 4x10-2 m
• 2

2 4 Vertical Position

• 40mm
• 20

20 40 Horizontal Position

140x106 120 100 80 60 40 20 Phot/s/0.1%bw/mm

• 40mm
• 20

20 40 Horizontal Position

0.1 THz 3.3 cm-1 JLab THz Beam Pattern on Mirror 1

Jefferson Lab THz spectra and total power

1 10 100 1000 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1 1 10 100 1000 10000 100000

Frequency (THz) Watts/cm

• 1

Frequency (cm

• 1)

100 MHz 100 pC 150 x 150 mr 0.1 ps 0.3 ps 1.0 ps 0.1 1 10 840 W

540 W

54 W

M1 V1 M2 M3 diamond window Shutter/viewer & camera M1 JLab Terahertz Beam Extraction and Transport

Operated by the Southeastern Universities Research Association for the U.S. Department of Energy

Thomas Jefferson National Accelerator Facility

Mirror 1 - courtesy of Richard Wylde, (Thomas Keating)

JLab power permits large area imaging ~ m2

Optical transport output in User Lab Real time image Ray trace 10mm2

Operated by the Southeastern Universities Research Association for the U.S. Department of Energy

Thomas Jefferson National Accelerator Facility

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 from

the target region (transmission mode generally not useful)

• Filtering of the THz induced thermal IR
• Properly imaging onto a detector array
• Creating imaging arrays designed specifically for THz

imaging

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

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. beamline mirror 1 mirror 2 mirror 3

• bject

moves/rotates visible camera THz camera THz filter/lens THz filter/lens

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

THz Imaging Layout

THz Induced Thermal IR

Raw Data Processed Data

• Images taken using the stock Ge lens
• THz passes through paper target and is reflected off of the

imaging target

• Heating due to absorption of THz heats the paper and the

imaging target, producing the thermal IR seen above

Beam ON Beam OFF paper target imaging target paper target imaging target

Test Pattern Imaging Target

Test of Imaging Resolution

Raw Data Processed Data

• Raw THz images are processed to reduce the background and

improve contrast

• Current configuration resolved down to the 1mm wide contact pads
• Polyethylene lens filtered the thermal IR, but does not image well

35 mm 35 mm 26 mm 26 mm

THz Imaging Covered Target

Raw Data Processed Data

CD mailer covering cloth covering

• 4. THz effects

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

• Many applications for THz sources
• High-power sources and detectors are being developed
• Bioeffects need to be understood for the health and safety
• f personnel
• Bioeffects efforts need to catch up to or even lead

technology development

• Bioeffects data pertaining to the health effects of high-

powered THz exposure are non-existent

Human Effects, contd. - Jill McQuade

Brooks Air Force Base – Human Effects Division, Terahertz Team

Molecular Biologist: Biotechnology HEDR

• Dr. Walter Hubert

Physiologist: Expt HEDR–GD-AIES Cont

• Mr. Alex Salazar

Physiologist: Expt, protocol HEDR–GD-AIES Cont

• Dr. Ron Seaman

Physicist: Expt HEDO-NG Cont

• Mr. Victor Villavicencio

Physicist: Expt HEDO

• Dr. Semih Kumru

Biologist: Expt, pilot lead HEDO

• Ms. Nichole Jindra

Biomedical Scientist: Modeling HEDR

• Mr. Jason Payne

Physicist: Modeling HEDO

• Dr. Bob Thomas

Physiologist: Project Lead HEDR

• Dr. Jill McQuade

• Performed at Jefferson Laboratory
• Experimental Validation of models

– characterization of the beam – exposures of wet chamois, 2 phantoms

10 20 30 40 50 60 2 4 6 8 10 12 14 16 Irradiance (W/cm

2)

Tem perature Rise (C)

Brooks Terahertz Experiments & Modeling

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

Laboratory layout for spectroscopy & pump-probe

Measured JLab – FEL THz Spectrum in Air

JLab - FEL THz spectrum τ p ~ 350 fs

0.00 0.05 0.10 0.15 0.20 0.25 0.30 1 2 3 4

THz Intensity (arb. units)

0.00 0.05 0.10 0.15 0.20 0.25 0.30 20 40 60 80 100 120 140

Wavenumber (cm-1)

Early IRSR experiments

GLOBAR SYNCHROTRON! >10x worse!! BESSY 1 1985-86

N2O

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 array path difference

THz HFTS during experiments at Jefferson Lab FEL

Coherent synchrotron radiation measurements

Interferograms Calculated spectra

Some of the JLab Team

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.

Photo taken Jan 16, 2007

1 10 100 1000 10000 1E-12 1E-11 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1 1 10 100 1000 10000

Energy (meV) Flux (Watts/cm

• 1)

Wavenumbers (cm

• 1)

1 10 100 1000

JLab THz S y n c h r

• t

r

• n

s G l

• b

a r JLab FEL Table-top sub-ps lasers Jefferson Lab Facility Spectroscopic Range and Power

FEL proof of principle: Neil et al. Phys. Rev.Letts 84, 662 (2000) THz proof of principle: Carr, Martin, McKinney, Neil, Jordan & Williams Nature 420, 153 (2002)

Conclusions

• We have a high power CSR THz source capable of illuminating a

large 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 deployed

systems (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

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.

Photo taken Jan 16, 2007

EXTRA SLIDES

Example of niche of 4th. Generation → Si:H H2

*

HBC

(+)

IH2 VH2 V2H 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

10 20

• 3
• 2
• 1

Ln[Sb] Time delay (ps)

T1 = 7.8 ± 0.2 ps

HBC

(+)

Defect Dynamics Luepke et al. CWM/Vanderbilt

20 40 60 80 100 120 140 160 180 200 220 240

• 120
• 100
• 80
• 60
• 40

NSLS Beamline U12IR 1.8K Bolometer Bruker 125 12mm aperture, no sample 600 mA beam current

dB(u) Frequency (Hz)

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

Source

Detector Chop (ω)

Experimentation Issues

• Over the past 10 years Jefferson Lab has constructed and commissioned a

next 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 on

high pressure research.

Concluding Remarks

Summary

• Tremendous opportunities
• In class of our own
• Must stay at scientific frontiers
• Great local university teams
• Helping Florida State, Cornell, Daresbury and
• ther 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.

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

Synchrotron SnCl4/silica Daresbury 1998 200 secs

Engstrom and Ryberg,

• J. Chem. Phys. 115 519 (2001)

Globar CO/Pt 3 days!! 105 secs

Paul Dumas and collaborators

• many papers

Daresbury data holds world record!!

200 400 600 800 1000 1200 1400 1600 Amplitude (arb. units) Frequency (Hz)

JLab FEL Drive Laser Noise Michelle Shinn

~100 V fsec laser pulse

GaAs THz

6 4 6 6 8 2 2 6 17 2

100V V E 10 m 10 m F 10 V 10 ( 3 10 ) a m .5MeV / c 0.5 10 m 10 sec

−

= = × = = = × ≅

2 8 2 17 2

c ( 3 10 ) m a 10 sec ρ 1 if ρ 1 m × = = ≅ =

fsec laser pulse

e- -> 40 MeV

GaAs THz ρ Comparing Conventional THz Sources and Coherent THz Synchrotron

2 2 4 3

2 Larmor's Formula: Power (cgs units) 3 e a γ c =

4 9

200 200 10 !!!! and γ = =

a=acceleration c=vel. of light γ=mass/rest mass

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

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

T2 - Time Scale for Coherent Synchrotron Radiation

T1

E l e c t r i c f i e l d time

• freq. (1/time)

super-radiant enhancement

N

E/N I n t e n s i t y ⏐ E2 ⏐ electron(s) Coherent Synchrotron Radiation Generation

2 3 8

1 5 t 0.25Attoseconds c 4000 3 10 ρ ∆ γ γ = = ≈ × ×

Multiparticle coherence – Free Electron Laser

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

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

297 cm-1 277 cm-1 163 cm-1 144 cm-1 133 cm-1 215 cm-1 80 cm-1 48 cm-1

Injector Cryomodule Wiggler Beam Stop Gun

Periodic Magnetic Field Electron Beam Total Reflector Niobium SRF Cavity with Oscillating Electromagnetic Field

Schematic of JLab 4th. Gen. Light Source Operation

Light Output

Electron Beam Drive Laser Output Mirror

Laser Wavelength ~ Wiggler wavelength/(2Energy)2

20 40 60 80 100 120 140 160 180 200 220 240

• 120
• 100
• 80
• 60
• 40

NSLS Beamline U12IR 1.8K Bolometer Bruker 125 12mm aperture, no sample 600 mA beam current

dB(u) Frequency (Hz)

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

Source

Detector Chop (ω)

Experimentation Issues

Generic Light Source Landscape – Average Brightness

1E-4 1E-3 0.01 0.1 1 10 100 1000 10000 10

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Photons/sec/0.1%BW/mm

2/milliradian 2

Gwyn Williams - file brt_1.bas May 25, 2006

L A R M O R L I M I T

4GLS 1x1nm (x10

10 for multiparticle)

3GLS 10 x 500 microns (x500 for ID) 2GLS 500x1000 microns

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

Photon Energy (eV)

• 1st. Generation – parasitic use of nuclear and high energy physics machines
• 2nd. Generation – dedicated storage rings – higher current, lower emittance
• 3rd. Generation – storage rings with insertion devices (wigglers), lower

emittance

• 4th. Generation – typically linac based, lower emittance, multiparticle

coherence General Landscape – Light Source “Generations”

1E-4 1E-3 0.01 0.1 1 10 100 1000 10000 10

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Photons/sec/0.1%BW/mm

2/milliradian 2

Gwyn Williams - file brt_1.bas May 25, 2006

L A R M O R L I M I T

4GLS 1x1nm (x10

10 for multiparticle)

3GLS 10 x 500 microns (x500 for ID) 2GLS 500x1000 microns

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

Photon Energy (eV)

Generic Light Source Landscape – Average Brightness

JLAB THz JLAB FEL LCLS XFEL UVFEL 4GLS 4GLS FSU

Generic Light Source Landscape – Peak Brightness

1E-4 1E-3 0.01 0.1 1 10 100 1000 10000 10

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Photons/sec/0.1%BW/mm

2/milliradian 2

Gwyn Williams - file brt_1.bas May 25, 2006

LARMOR LIMIT

DIPOLE 2GLS 500x1000 microns 500 ps FWHM INSERTION DEVICE 3GLS 10 x 500 microns (x500 for ID) 50ps FWHM MULTIPARTICLE ENHANCEMENT 4GLS 1x1nm 50fs FWHM (x10

10 for multiparticle)

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

Photon Energy (eV)

1E-4 1E-3 0.01 0.1 1 10 100 1000 10000 10

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Photons/sec/0.1%BW/mm

2/milliradian 2

Gwyn Williams - file brt_1.bas May 25, 2006

LARMOR LIMIT

DIPOLE 2GLS 500x1000 microns 500 ps FWHM INSERTION DEVICE 3GLS 10 x 500 microns (x500 for ID) 50ps FWHM MULTIPARTICLE ENHANCEMENT 4GLS 1x1nm 50fs FWHM (x10

10 for multiparticle)

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

Photon Energy (eV)

Generic Light Source Landscape – Peak Brightness

JLAB THz

J L A B 4 G L S U V F E L F L A S H X F E L L C L S

FSU

First CSR Science: First CSR Science: Josephson Plasma Resonance in Josephson Plasma Resonance in Bi Bi2

2Sr

Sr2

2CaCu

CaCu2

2O

O8

8

+ Indications for inhomogeneous superfluid

• M. Abo-Bakr et al. Phys. Rev. B 69 (9),

092512 (2004).

λc = 21 µm Data from Nov. 2002

Non-linear dynamical effects using high field THz light

A biopolymer chain buckles and folds on itself due to an instability produced by a nonlinear localized mode – Physics Today Jan. 2004 p43. Mingaleev et al Europhys. Lett. 59 403 (2002)

High electric fields are predicted to generate localized modes! JLab collaboration with Al Sievers, Cornell U.