1. All-optical accelerators
LOASIS Program:
All-optical accelerators
Wim Leemans
LOASIS Program
Accelerator and Fusion Research Division
Website:

2. Acknowledgment Staff/students of l’OASIS team
E. Esarey, C.Filip*, G. Fubiani, C. Geddes, E. Michel*, P. Michel, B. Nagler,
K. Nakamura, C. Schroeder, B. Shadwick, C. Toth, J. van Tilborg,
D. Syversrud, M. Dickinson, N. Ybarrolazza, J. Wallig
*University of Nevada, Reno
Primary Collaborators
S. Hooker, A. Gonsalves- Oxford University
D. Jaroszynski-Strathclyde, AlphaX
T. Cowan, N. Le Galloudec, H. Ruhl, A. Kemp- UNR
J. Cary, D. Bruhwiler, D. Dimitrov-U Colorado Boulder, TechX-Corp
DOE -HEP Advanced Accelerator Technology 7 3 2 1 1 1 1 1

3. Challenges Building a high energy collider: Radiation source
Single stage ?
200 m long plasma, BIG laser (200 PW for 1 TeV?)
Will beam remain stable ? Will emittance be OK?
Multi-stage ?
How to stage ? Build 10 GeV module, how to couple beams in and out ?
How to manage , PW systems? 100 Hz?
Radiation source
Coherent emission: THz
X-FEL: is beam quality good enough ?
Energy spread
Emittance
Maintaining peak current: bunch propagation
Particle source:
fs, MeV electron bunches, pC, 10 micron spot, E/E <<

4. Experimental activities/focus
10 TW system
High density plasma channels
“Low” phase velocity wakes
Dark current free structure
100 MeV-class beams
Injection physics
THz and X-rays
100 TW system
Low density plasma channels
“High” phase velocity wakes
1 GeV module
Capillary discharge:
Collab. With Oxford (UK)
CCD &
Spectrometer 2w
probe
Interferometer
Heater beam e-
H, He gas jet
Main beam
Ignitor
Beam

5. + Next step: 1 GeV compact module 100 TW laser + plasma channel Plasma
A. Reitsma et al., PR-STAB 2001
Plasma
injector
Plasma channel
e- beam
< 3mm
< 10 cm
1.2 GeV
Laser
100 TW, 40 fs
10 Hz
Collaboration with Oxford University and Alpha-X
Bigger laser
2-7 cm long +

6. LWFA’s brightness offers unique opportunities
Brightness = (beam power)/(phase space volume)
Brightness
Particle energy [GeV]
Brightness vs. g
SLAC FFTB
10 GeV LWFA
1 GeV LWFA
LOA
LBNL
RAL
Photocathode
Thermionic
Data: Nature 2004

7. Single drive beam experiments have been conducted for laser accelerator produced THz and X-rays
Set-up for E-O effect
THz emitted at vacuum-plasma boundary
Short bunches result in coherent emission
Radiation source+bunch diagnostic
Radiation characterized via:
Michelson interferometer
Semiconductor switching
Electro-optic effect in ZnTe
THz TR
50fs Probe
Beam (800nm)
Polarizer
Analyzer
ZnTe
Diode
Chamber
/4

8. Time Jitter and Stability
Shot-to-shot stability in charge and bunch duration enables scanning E-O sampling technique
Time Jitter and Stability
Jitter
e-beam &
probe beam
must be
<< 30 fs
Charge Stability over Time < 5 % rms
Spectrum consistent with 50 fs bunch
THz depends primarily on charge,
bunch duration
Shot-to-shot stability of those quantities
J. Van Tilborg et al., in preparation

9. Ultra-short x-ray generation from laser accelerated e-beams
Betatron emission:
“Spontaneously” emitted
Detector testing
First phase of x-ray diagnostic
Collaborations:
LLNL
UNR lu
lx=lu/2g2
Betatron (synchrotron) radiation:
E. Esarey et al., PRE 2002
A. Rousse et al., PRL 2004
parameters:
Q=03 nC
E=100 MeV
rb=3 mm
ne=2 x1019 cm-3
Lchannel=1 mm

10. LOASIS Program at LBNL Tools: multi-beam, multi-arm laser
Radiation shielded experimental areas+remote control room
Two target areas:
10 TW (+10 TW), 3 independent vacuum compressors
100 TW arm
Physics:
Precision frontier: all-optical injection enabled by discovery of dark current free structure
High energy acceleration:
Channel guided laser wakefield: 100 MeV (Nature 2004)
Capillary discharge + injection: towards 1 GeV
Radiation sources: taking advantage of peak brightness
Intense THz via coherent transition radiation (PRL 2003, PRE 2004, PRL 2005(submitted))
Incoherent x-rays: betatron, Thomson scattering-gamma rays
Coherent x-rays: XFEL

11. LOASIS Program FY05: Staff + visitors and students