Advanced Accelerator Physics at SLACAdvanced Accelerator Physics at SLAC

T. Katsouleas, S. Deng, S. Lee, P. Muggli, E. OzUniversity of Southern California

B. Blue, C. E. Clayton, V. Decyk, C. Huang, D. Johnson, C. Joshi, J.-N. Leboeuf, K. A. Marsh, W. B. Mori, C. Ren, F. Tsung, S. Wang

University of California, Los Angeles

R. Assmann, C. D. Barnes, F.-J. Decker, P. Emma, M. J. Hogan, R. Iverson, P. Krejcik, C. O’Connell, P. Raimondi, R.H. Siemann, D. R. Walz

Stanford Linear Accelerator Center

Beam-Driven Plasma Acceleration: E-157, E-162, E-164, E-164X

R. L. Byer, T. Plettner, T. I. Smith, R. L. SwentStanford University

E. R. Colby, B. M. Cowan, M. Javanmard, X. E. Lin, R. J. Noble, D. T. Palmer, C. Sears, R. H. Siemann, J. E. Spencer, D. R. Walz, N. Wu

Stanford Linear Accelerator CenterJ. Rosenzweig

University of California, Los Angeles

Vacuum Laser Acceleration: LEAP, E-163

Science Innovation

1,000 TeV

10,000 TeV

100,000 TeV

1,000,000 TeV

100 TeV

10 TeV

1 TeV

100 GeV

10 GeV

1 GeV

100 MeV

10 MeV

1 MeV

1930 1950 1970

Year of Commissioning

1990 2010

Par

ticl

e E

ner

gy

Proton Storage RingsColliders

ProtonSynchrotrons

Electron Linacs

Synchrocyclotrons

Proton Linacs

Cyclotrons

ElectronSynchrotrons

Sector-FocusedCyclotrons

ElectrostaticGenerators

RectifierGenerators

Betatrons

Electron PositronStorage Ring Colliders

Electron ProtonColliders

LinearColliders

A “Livingston plot” showing the evolution of accelerator laboratory energy from 1930 until 2005. Energy of colliders is plotted in terms of the laboratory energy of particles colliding with a proton at rest to reach the same center of mass energy.

Particle Physics Discoveries

• 2 ν’s• J/ψ• W & Z• top

Accelerator Innovations• Phase focusing• Klystron• Strong focusing• Colliding beams• Superconducting magnets• Superconducting RF

Vacuum Laser Acceleration: LEAP, E-163

R. L. Byer, T. Plettner, T. I. Smith, R. L. SwentStanford University

E. R. Colby, B. M. Cowan, M. Javanmard, X. E. Lin,R. J. Noble, D. T. Palmer, C. Sears, R. H. Siemann,

J. E. Spencer, D. R. Walz, N. WuStanford Linear Accelerator Center

J. RosenzweigUniversity of California, Los Angeles

Motivation For This Research

J. Limpert et al, “Scaling Single-Mode Photonic Crystal Fiber Lasers to Kilowatts”

Pump Power

Output P

ower

73%

CW

Output P

ower

1 kW

20061992

Carrier Phase-Locked LasersDiddams et al

“Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb”, Phys. Rev. Lett., 84 (22), p.5102, (2000).

Photonic Crystal Fibers

X. Lin, Phys. Rev. ST-AB, 4, 051301 (2001).

e- beam passageradius = 0.678 λ

Fused SilicaVacuum Holes

False color map of Ez

The photonic crystal confines the accelerating mode to the region near

the beam tunnel

Blaze Photonics

Large aperture fiber(not an accelerator)

E163 – Laser AccelerationExperiment

RF PhotoInjector

Ti:Sapphire LaserSystem

60 MeV Experi-mental Hall

Experiment

crossedlaser beams

electronbeam

acceleratorcell

~ 1 cm

crossedlaser beams

electronbeam

crossedlaser beams

electronbeam

crossedlaser beams

electronbeam

acceleratorcell

Imageintensifiedcamera

doped YAGscreen

spectrometermagnet

Diagnostics:•spatial monitor•streak camera

~ 1 m

Imageintensifiedcamera

doped YAGscreen

spectrometermagnet

Diagnostics:•spatial monitor•streak camera

The E163 Experimental Setup

Camera

Electron beam

Vacuum chamber

An example of alaser driven

accelerator stage

T. Katsouleas, S. Deng, S. Lee, P. Muggli, E. OzUniversity of Southern California

B. Blue, C. E. Clayton, V. Decyk, C. Huang, D. Johnson, C. Joshi,J.-N. Leboeuf, K. A. Marsh, W. B. Mori, C. Ren, F. Tsung, S. Wang

University of California, Los Angeles

R. Assmann, C. D. Barnes, F.-J. Decker, P. Emma, M. J. Hogan, R. Iverson, P. Krejcik, C. O’Connell, P. Raimondi, R.H. Siemann, D. R. Walz

Stanford Linear Accelerator Center

Beam-Driven Plasma Acceleration: E-157, E-162, E-164, E-164X

Plasma Wakefield AccelerationE157, E162, E164 & E164X

6 8 1 0 2 0 4 0 6 0 8 01 0 0 2 0 0

1 03

1 04

1 05

1 06S h o t 1 2 (1 0 k G )S h o t 2 6 (1 0 k G )S h o t 2 9 (5 k G )

S h o t 3 3 (5 k G )S h o t 3 9 (2 .5 k G )S h o t 4 0 (2 .5 k G )

Rel

ativ

e #

of e

lect

rons

/MeV

/Ste

radi

an

E le c tro n e n e rg y ( in M e V )

SM-LWFA electron energy spectrum

A. Ting et al, NRL

Motivation For These Experiments

Extraordinarily high fields developed in beam plasma interactions but there are many questions related to the applicability for focusing and acceleration

Self modulated laser wakefield acceleration

E > 100 MeV, G > 100 GeV/m

Physical Principles of the PlasmaPhysical Principles of the PlasmaWakefield AcceleratorWakefield Accelerator

• Space charge of drive beam displaces plasma electrons• Plasma ions exert restoring force => Space charge oscillations

• Wake Phase Velocity = Beam Velocity

• When σz/λp ~1 (⇒ Np ~1/σz2)

++++++++++++++ ++++++++++++++++

----- -------------------

---- -----------

-------- --------------------------- --

-

---- --- ---

-------

- -- ------ - -- ------ - -

- - - - --- --

- -- - - - - -

--------

------ electron beam

+ + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + ++ + + + + + + + + + + + + + +-

- --

--- --

EzEz

2~ bpk

z

NEσ

• Optical TransitionRadiation (OTR)

• Cherenkov (aerogel)

- Spatial resolution ≈100 µm - Energy resolution ≈30 MeV

-1:1 imaging,spatial resolution ≈9 µm

y,E

x

U C L A

e-

N=1.8×1010

σz=20-12µmE=28.5 GeV

Optical TransitionRadiators

IP0: Li Plasma Gas Cell: H2, Xe, NO

ne≈0-1018 cm-3

L≈2.5-20 cm

Plasma light

X-RayDiagnostic,

e-/e+

Production

CherenkovRadiator Dump

∫Cdt

ImagingSpectrometer

IP2:

xz

y

EnergySpectrum“X-ray”

25m

CoherentTransition

Radiation andInterferometer

y

x

Upstream

y

x

Downstream

• X-rayChicane

-Energy resolution ≈60 MeV

• Plasma Light

E

λ

Apparatus Located in the FFTB

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

-8 -4 0 4 8

05190cec+m2.txt 8:26:53 PM 6/21/00impulse model

BPM data

θ (m

rad)

φ (mrad)

plasma

gasbeam

Blowout region

Ion channel

laserφθ

Electron Beam Refraction at the Gas–Plasma Boundary

e+ Acceleration

Some E-157 & E-162 Highlights

X-Ray Production

e+

Total internal reflectionImpulse Model Data e+ Focusing

Noplasma

1.5x1014 cm-3

0

50

100

150

200

250

300

-2 0 2 4 6 8 10 12

05160cedFit.2.graph

σX

DS

OTR

(µm

)

K*L∝ne1/2

σ0 uv Pellicle=43 µm

εN=9×10-5 (m rad)β0=1.15m

Transverse Wakefields and Betatron Oscillations

Some E-157 & E-162 Highlights

MismatchedMatched

Beam Image

Tim

e

Horizontal Dimension

Head

Tail

~5 p

sec

e- Acceleration1.4 m long plasma

1.5x1014

1.9x1014

F = -eEz

electron beam

front portion of bunch

loses energyto generate

the wake

back portion of bunch isaccelerated

En

ergy

Head Tail

No Plasma

With Plasma

BeamDistribution

e-ion column

Recent results address the question of whether large gradients can be generated and sustained over appreciable distances

Key: G ~1/(bunch length)2

High-gradient acceleration of particles possible over a significant distance

Tilt is due to small, uncorrected horiz. dispersion

A single 200 sec long run sorted by a rough measurement of peak current

Density = 2.55×1017/cm-3

7.4 GeV

SummarySummary

Plasma Wakefield Acceleration• Electron & positron transport and acceleration in a long plasma• Accelerating gradients greater than 15 GeV/m sustained over 10 cm• Many results to come: higher gradients, more energy gain, trapped particles, multiple bunches, …

Laser-driven accelerator structures• Based on rapidly advancing field of photonics• Concepts for accelerator structures• Analyses of wakefields and efficiency• Promise of rapid experimental advances with construction of SLAC experiment E163