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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
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