AARD subpanel Dec 21, 2005 Laser driven particle acceleration€¦ · coated Kapton tape stepper motors broadening of the initial energy spread of the electron beam 9. The SCA-FEL

FWH

M e

nerg

y sp

read

(keV

)

laser timing (psec)

FWH

M e

nerg

y sp

read

(keV

)

laser timing (psec)

laser on

laser off

Laser driven particle acceleration

collaborators

ARDB, SLACBob Siemann*, Bob Noble†, Eric Colby†, Jim Spencer†, Rasmus

Ischebeck†, Melissa Lincoln‡, Ben Cowan‡, Chris Sears‡, D. Walz†, D.T. Palmer†, Neil Na‡, C.D Barnes‡, M Javanmarad‡, X.E. Lin†

Stanford UniversityBob Byer*, T.I. Smith*, Y.C. Huang*, T. Plettner†, P. Lu‡, J.A. Wisdom‡

ARDA, SLACZhiu Zhang†, Sami Tantawi†

Techion Israeli Institute of TechnologyLevi Schächter*

UCLAJ. Rosenzweig*

AARD subpanel Dec 21, 2005

‡ grad students † postdocs and staff * faculty

Outline

• Introduction• Properties unique to laser acceleration • Available resources and expertise• Emergence of new technologies

• The physics concept and experiment• The physics concept• The physics demonstration experiment

• Current and future research• The E163 experiment• Accelerator structure investigations• Multi-staged laser accelerator

• Future scientific impact• Candidate technology for a TeV scale collider• Soft X-ray attosecond physics


The Livingston plot – 1954Innovation leads to exponential progress

In 1954 Livingston noted that progress in high energy accelerators was exponential with time.

Progress was marked by saturation of the current technology followed by the adoption of innovative new approaches to particle acceleration.

Over the past two decades progress in Advanced Solid State Lasers has been driven by innovation. Laser sources coupled with related technologies enable new approaches to Advanced Electron Accelerators.

Particle accelerator research at Stanford

1st Klystron (Varian, 1930s’) 1st Linac 1946

The superconducting linacIn HEPL, 1960

Demonstration of the FEL, 1977

The 2-mile collider (SLAC)

LEAP, 1997-2004


Vacuum laser acceleration

Energy gain through longitudinal electric field• gradient = longitudinal electric field• linear e-beam trajectory

no synchrotron radiationenergy scalable

Dielectric based structure with vacuum channel

very high peak electric fields

Inherent attosecelectron pulse

2 µm laser 6 fsec period 1 of phase = 20 attosec

Unique opportunity for light sources

linear particle acceleration

process

11

22

33λ ~ 2 µm, T~ 6.6 fsec

T~ 20 attosec1° of optical phase

electric field

electron bunch

λ ~ 2 µm, T~ 6.6 fsec

T~ 20 attosec1° of optical phase

electric field

electron bunch

∆U E dzz= ⋅∫

vacuum channel

NIR solid-state lasers

metals

Es → 1010 V m

Gradient GeV m→ 1


NUFERN

ALABAMA LASER

high powerfiber lasers

ultrafast laser technology

nanotechnology

60 W/bar, 50% electr. efficiency

efficient pump diode lasers

< 10 fsIMRA mJ 500

fsec laser

new materials

high strength magnets

New ceramicsNd:Fe

nano-tubes

high purity optical materials and high strength coatings

sodium yellow

Leveraging investment in

telecom

30 W/bundle, 40% electr. efficiency

Emergence of new technologies


Available resources at Stanford/SLAC

Materials science and nanofab capabilities

time evolution of 111 Bragg peak of

InSb

Ultrafast light and Xray science at SLAC

The gravitational wave detector

Lasers, Optics and photonics

Fundamental science

questions

Strong interaction and partnership with

• industry• national labs• other universities

worldwide

MedicineChemistryBiology…

Accelerator and diagnostics expertise at SLAC

The NLCTAbeamline


Laser acceleration concept

8

laser out

dielectric waveguide structure

∆U E dzz= ⋅∫

Pantell, 1979conceptual ideaelectron

bunchaccelerating

forcelaser in

laser beamdielectricmaterial

electronbeam

z

( ) 00

>′′∫ zdzEd

z

boundary

vacuum channel

Magnitude Phase

Gouy PhasePlane Wave Phase Math

( )

( ) ( ) 01

222

233

22

22ˆ

2/3220

cosˆtan2cosˆ1tancosˆ

cos

coscosˆ1sin

exp)cosˆ1(

sin2

φθθθθθωθψ

ψθθ

θθ θ

+⋅−+

⋅+⋅−⋅⋅=

×

+−

+−=

− zz

ztzk

zzEE

dt

t

z

zd

†P. Sprangle, E. Esarey, J. Krall, A. Ting, Laser Accelerationof Electrons in Vacuum, Optics Comm. 124 (1996) 69

E1

E2

E1z

E2z

E1x

E2x

z

x

( ) ( ) zdzEzUz

zz ′′= ∫

0


Laser ONLaser OFF

Observed energy profiles

Laser ONLaser OFF


Laser ONLaser OFF


0 20 40- 40 - 20

0.2

0.4

0.6

0.8

1.0

Energy spread (keV)

Nor

mal

ized

cha

rge

per u

nit e

nerg

y Laser ONLaser OFF


Laser ONLaser OFF


Laser ONLaser OFF


0 20 40- 40 - 20

0.2

0.4

0.6

0.8

1.0

Energy spread (keV)

Nor

mal

ized

cha

rge

per u

nit e

nerg

y

The LEAP experiment(Laser Electron Accelerator Project)

electronbeam

laserbeam

spectrometer

The field-terminating boundary

camera

0 ½π−π -½πoptical phase of the laser

elec

tron

ener

gy+∆

Um

ax−∆

Um

ax

acceleratingphase

deceleratingphase

E dzz ⋅ >−∞∫0

0


8 µm thick gold-coated Kapton tape

stepper motors

broadening of the initial

energy spread of the electron

beam

9

The SCA-FEL facility

LEAParea

collimatorslits

amplified laserBeam Energy ~30 MeVTelectron ~2 psecCharge per bunch ~5 pCEnergy spread ~20 keVλlaser 800 nmElaser 1 mJ/pulse

SCA beam parameters

Commercial, tabletop amplified sub-psecmJ/pulse laser sources

FELwiggler

superconductingaccelerator structures kicker


Tomas Plettner and LEAP Accelerator Cell

The key was to operate the cell above damage threshold to generateEnergy modulation in excess of the noise level.

We accelerated electrons with visible light

FWH

M e

nerg

y sp

read

(keV

)

laser timing (psec)

FWH

M e

nerg

y sp

read

(keV

)

laser timing (psec)

laser on

laser off Laser Polarization Angle θ (degrees)

Ave

rage

Ene

rgy

Mod

ulat

ion

⟨M⟩(

keV

)

Laser Polarization Angle θ (degrees)

Ave

rage

Ene

rgy

Mod

ulat

ion

⟨M⟩(

keV

)

Peak Longitudinal Electric Field Ez (MV/m)

0.1 0.2 0.3 0.4Laser Pulse Energy (mJ/pulse)

0.05

Ave

rage

Ene

rgy

Mod

ulat

ion

⟨M⟩(

keV

)

( ) ( )25.035.0017.0349.0 ±−⋅±= zEM

modelM simulation

M data

zEM ⋅= 361.0model

Peak Longitudinal Electric Field Ez (MV/m)

0.1 0.2 0.3 0.4Laser Pulse Energy (mJ/pulse)

0.05

Ave

rage

Ene

rgy

Mod

ulat

ion

⟨M⟩(

keV

)

( ) ( )25.035.0017.0349.0 ±−⋅±= zEM

modelM simulation

M data

zEM ⋅= 361.0model

• confirmation of the Lawson-Woodward Theorem

• observation of the linear dependence of energy gain with laser electric field

• observation of the expected polarization dependence

E dzz−∞

+∞

∫ = 0

∆U Elaser∝

E Ez laser∝ cosρ

laser-driven linear

acceleration in vacuum


Visible light driven IFEL

Cross-correlation in time Observation of harmonic interaction

* graduate student C.M. SearsAARD subpanel Dec 21, 2005

13

Outline




• Future scientific impact• Candidate technology for a TeV scale collider• Soft X-ray attosecond physics


The E163 experiment at SLAC

The new E163 experiment hall

The NLCTA

new RF gun

X-band structure

7 MeV 60MeV

interaction chamber

spectrometer

x3266 nm

NLCTA tunnel experimenthall

Ti:sapphirelaser system

800 nm

X-band structures

Chicane• compressor•energy filter

RF gun 300MeV

Accomplished mile stones so far• construction of the experiment hall• installation of the E163 control room• commissioning of the laser system• installation and commissioning of the RF gun

Expected 1st experiment in spring 2006


The next step: staged accelerators at E163

16

The IFELThe compressor chicane

The triplet

optical buncher

opticalaccelerator

compressor chicane

laser

Accelerator structure

focusing triplet


Accelerator structure research

Photonic bandgap fiber structures 2 and 3-D photonic bandgap structures

R. Ischebeck, R. J. Noble, B.Cowan*, M. Lincoln*,C. Sears* *grad. students

Current experimental fiber accelerator structure research

Planar waveguide structures


Progress in laser accelerator physics

Energy efficiency of laser accelerators, single and multiple bunch operation

Beam loading calculations vs N Coupling Efficiency vs bunch charge

N (Number of bunches)

optimum efficiencyabout 1 fC


Application of modern technologies

Lasers and photonicsMaterials science200 fsec Yb:fiber laser; S. Sinha*

comb offset detection with Ti:Sapph lasers; T. Plettner

*grad. students

J. Wisdom*, R. Gaume

Before HIP

2 hr 1600Cno Ar

2 hr 1700Clow Ar

2 hr 1800Chigh Ar

YAG ceramic

A pbg coupler

S. F

an e

t al,

PR

L 80

, 5, 9

60-9

63 (1

998) PBG structure coupler


Outline




• Future scientific impact• Candidate technology for a TeV scale collider• soft X-ray attosecond physics


Envisioned laser-driven TeV-scale accelerator

Optical Injector• optical cycle e- bunch• ~104 electrons/bunch• ultra low emittance• laser-driven field emitters Pre-accelerator

• nonrelativistic• compress bunch Accelerator structures

• preserve emittance• periodic focusing• alignment and stabilization• coupling efficiency

Electron beam• 1 fC/bunch• sub µm spot size• ~1010 bunches/sec

Initial focus of our research • success of proof-of-principle exp.• research on dielectric structures

Collider area• sub-Ångstrom spot size• multi-GHz rep-rate

Phaslocked Oscillators • 100fsec, 1 GHz rep. rate• Phaselocked to clock

Power Amplifiers• NIR 1-2 µm wavelength• 1 kW @ 50% efficiency• ~50 kW/m optical power

Order-of-magnitude power estimate• 1 fC x 1010 x 1 TeV 107 W e-beam• 20% coupling 5x107 W optical power• 50% wallplug laser 108 W electricity

100 MW electricity

Tungsten tip fsec field emitters

P. Hommelhoff et al

LIGO vibration isolation in ES3 at Stanford

block-diagram

~Optical clock• ultrastable• attosec stability• low power


Soft X-ray attosecond physics

attosec light sources

N

S N

S N

S N

S N

S N

S N

S N

S

N

S N

S N

S N

S N

S N

S N

S N

S

N

S N

SN

S N

S N

S N

SN

S N

S N

S N

SN

S N

S N

S N

SN

S N

S

N

S N

SN

S N

S N

S N

SN

S N

S N

S N

SN

S N

S N

S N

SN

S N

S

low energy 100 MeVe-beam

Preliminary model studies• 1st initial feasibility study with the 1D FEL model• Attosec bunching of 1fC helps enhance the gain• “low” 1 MHz rep. rate low avg. power • Further more refined studies under way• It deserves a closer look

Take advantage of ultra-low emittance laser-accelerator e-beam and new magnetic materials

1m

110 VProf. Byer’s dream…

20 asecHigh strength Nd:Femicromagnets

The wizard of optics

1° of optical phase at 2 µm 20 attosec

compact attosec soft x-ray source with medical and chemistry applications


Summary

1st proof-of-principle Vacuum based laser acceleration demonstration

Conducting R&D on dielectric based accelerator structures

Envision an approach to a TeV scale laser driven particle accelerator


Selected publications

1. Y.C. Huang, D. Zheng, W.M. Tulloch, R.L. Byer, “Proposed structure for a crossed-laser beam GeV per meter gradient vacuum electron linear accelerator”, Applied Physics Letters, 68, no. 6, p 753-755 (1996)

2. Y.C. Huang, T. Plettner, R.L. Byer, R.H. Pantell, R.L. Swent, T.I. Smith, J.E. Spencer, R.H. Siemann, H. Wiedemann, “The physics experiment for a laser-driven electron accelerator”, Nuclear Instruments & Methods in Physics Research A 407 p 316-321 (1998)

3. X. Eddie Lin, “Photonic band gap fiber accelerator”, Phys. Rev. ST Accel. Beams 4, 051301 (2001)

4. E. Colby, G. Lum, T. Plettner, J. Spencer, “Gamma Radiation Studies on Optical Materials”, IEEE Trans. Nucl. Sci. Vol. 49, No. 6, p. 2857-2867 (2002)

5. B. M. Cowan, “Two-dimensional photonic crystal accelerator structures”, Phys. Rev. ST Accel. Beams 6 101301 (2003)

6. R.H. Siemann, “Energy efficiency of laser driven, structure based accelerators”, Phys. Rev. ST AB. 7 061303 (2004)

7. T. Plettner, R. L. Byer, R. H. Siemann, “The impact of Einstein’s theory of special relativity on particle accelerators”, J. Phys. B: At. Mol. Opt. Phys. 38 S741–S752 (2005)

8. Y. C. Neil Na, R. H. Siemann, R.L. Byer, “Energy efficiency of an intracavity coupled, laser-driven linear accelerator pumped by an external laser”, Phys. Rev. ST. AB. 8, 031301 (2005)

9. T. Plettner, R.L. Byer, E. Colby, B. Cowan, C.M.S. Sears, J. E. Spencer, R.H. Siemann, “Visible-laser acceleration of relativistic electrons in a semi-infinite vacuum”, Phys. Rev. Lett. 95, 134801 (2005)

10. C.M.S. Sears, E. Colby, B. Cowan, J. E. Spencer, R.H. Siemann, T. Plettner, R.L. Byer, “High Harmonic Inverse Free Electron Laser Interaction at 800 nm”, Phys. Rev. Lett. 95, 194801 (2005)

11. T. Plettner, R.L. Byer, E. Colby, B. Cowan, C.M.S. Sears, J. E. Spencer, R.H. Siemann, “Proof-of-principle experiment for laser-driven acceleration of relativistic electrons in a semi-infinite vacuum”, Phys. Rev. ST Accel. Beams 8, 121301 (2005)


Backup slides


TeV scale laser accelerator parameters

λ 2 µm

1 GHz

10

~6000 (1 fC)

0.1 µm

0.1 Å

10-11 m-rad

10 µm

~1034/cm2-sec

accelerator field wavelength

laser pulse repetition rate

bunches per laser pulse “macro-pulse”

electrons / bunch

accelerator beam diameter

beam diameter at IP focus

transverse geometric emittance

β at IP

approximate luminosity at IP

f1010/sec

n

N

σ

σ

ε

β0

L nfN

x y

≈2

4πσ σAARD subpanel Dec 21, 2005

26

TeV scale laser accelerator pulse structure

G 1 GeV/m

1 psec

20 attosec

target gradient

laser pulse duration

electron bunch duration

Tlaser

Te

1 nsec

macro pulse: 10 bunches

1 fC/ bunch1 psec

Ib 10 µA

10 MW

total beam current

total beam power at 1 TeV Pb


Soft X-ray attosecond physics - detail

LFODO ~ 1 cmoxy ~ 3 µm

ε ~ 10-9 m-rad~ 1 cmqb ~ 1 fC

LGLsat ~ 30 cm

28

frep ~ 1 MHzηacc ~ 1% Pacc ~ 10 W optical powerηlaser ~ 10 % wallplug efficiencyPe ~ 100 W optical power

1% of Ub = 10-7 J U ~ 107 Photons

~ 1 nJ/pulse

50 60 70 80 90 100 110 120 130 140 1500.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

be a m e ne rgy (Me V)

wav

e;en

gth

(nm

)

E = 100 MeVq = 6250 e/bunch (1 fC)λu = 100 µmDe = 3 µm

50 60 70 80 90 100 110 120 130 140 1500.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

be a m e ne rgy (Me V)

wav

e;en

gth

(nm

)

E = 100 MeVq = 6250 e/bunch (1 fC)λu = 100 µmDe = 3 µm

1

2

3

4

5

wav

elen

gth

(nm

)

60 80 100 120 140

beam energy (MeV)

λu ~ 100 µmλr ~ 1 nm

0 0.5 1 1.5 2 2.5 30

2

4

6

8

10

12

electron beam size (microns)

leng

th (m

m)

leng

th (m

m)

2

6

10

1 2 3

electron beam size (µm)

LG

LRL LR G>

E = 100 MeVq = 1 fC /bunchλu = 100 µm

0 0.5 1 1.5 2 2.5 30

50

100

150

200

250

300

350

400

450

500

electron beam size (microns)

ener

gy s

prea

d (k

eV)

EE ρσ ≤

100

200

300

400

1 2 3

electron beam size (µm)

ener

gy s

prea

d (k

eV)

10-3 10-2 10-1 100 101 10210-4

10-3

10-2

10-1

100

101

beam energy (GeV)

min

imum

FE

L w

avel

engt

h (n

m)

70 Å

100 MeV

ε ~10-3 µm-rad

λu ~ 28 µm

πλε4

r≤

0.1 1 100.01

beam energy (GeV)

min

,. FE

L w

avel

engt

h (n

m)

1

10

0.1

0.01

1-D FEL modelDesign parameters must satisfy these conditions

Starting point

~ 30 cm~ 1 cm ~ 3 µmUndulator

design

λb ~ 18 attosecUb ~ 10-7 J

Laser power required

1% conversion efficiency


The laser accelerator and IFEL

Cerenkov cell lens

IFEL

ITR

Cerenkov cell

Back-of-ITRPuckup mirror

(CH 24)

Motor 1(CH 21)

Motor 2

upstream

downstream


The tape boundary

1. Damage threshold• ignore it! • devise a “disposable” unit• materials retain their optical properties for a few picoseconds

after a destructive laser pulse

2. Cell geometry• simplify to one semi-infinite boundary• make boundary thin enough to run e-beam through it• make boundary movable to present a new surface for

each laser shot

3. Crossed laser beams• two laser beams too difficult? eliminate one of them• no more optical phase uncertainty problems

negligible transverse deflection forces

Improve on • Operation tolerances• Poor reliability• Ease of operation

crossedlaser beams

electronbeam

slit

1 cm

crossedlaser beams

electronbeam

slit

crossedlaser beams

electronbeam

slit

1 cm

Conceptual drawingof the improved setup

electronbeam

laserbeam

materialboundary

θelectronbeam

Ez

8 µm Kapton 1 µm Au

∆U E dzz=−∞∫0


The tape boundary

0.3

0.35

0.4

0.45

0.55

0.6

0.65

0.7

0 10 20 30 40 50 60

b) Reflected pulse intensity versus laser pulse duration

laser pulse duration (psec)

refle

cted

pow

er (a

.u.)

boundary

gated camera

a) Setup for the reflected spot measurements

reflected spot camera imagesi) low power, belowdamage threshold

ii) 1st shot, abovedamage threshold

laser

pulsecompressor attenuator

attenuator

0.5


Laser Electron Accelerator ProgramLocated in the Hansen Lab on Stanford Campus

interactionchamber

0 50 150-50-150energy (keV)

verti

cal c

oord

inat

e

e- beampulses

laser

pulses

90o

bendingmagnet

gatedcamera

acceleratorcell

crossedlaser beams

electronbeam

slit

1 cm

2 keVresolution

(a) (b)

The view of the 30 MeV super-conductinglinear accelerator in the undergroundtunnel on campus in the HEPL lab.

The crossed-beam laser acceleratorCell and magnet for electron beamenergy measurements.

Documents

AARD subpanel Dec 21, 2005 Laser driven particle acceleration€¦ · coated Kapton tape stepper motors broadening of the initial energy spread of the electron beam 9. The SCA-FEL