1. V. Bagnoud PHELIX, Plasma Physics department GSI Darmstadt
Status of the LIGHT project Laser ion Generation Handling and Transport
V. Bagnoud
PHELIX, Plasma Physics department
GSI Darmstadt
Photo M-Zweig ausgetauscht
EMMI Workshop: Nonlinear Dynamics of Simple Quantum Systems at Extreme Temperatures and Intensities

2. LIGHT coordinates activities in the field of particle acceleration at GSI
LIGHT aims at injecting laser-accelerated ions into conventional accelerator structures
The key factor is the transport of the source peak brilliance
The core LIGHT project is under realization at the Z6 Experiment place of GSI
The principle elements have been demonstrated separately
Integration will happen in 2012
Additional studies are being followed outside the baseline design to improve the setup performance
Reduction of the ion initial divergence by means of engineered laser beams is being investigated
Higher source brilliance via energy-peaked spectral distributions by RPA

3. Motivation: GSI is the ideal place to conduct this project
Leading expertise in both fields (laser acceleration, accelerator technology) available at GSI, surrounding universities, and HIJ
Z6 Target Area
PHELIX
Optimal use of laser accelerated ions requires beam forming, energy selection and debunching
Z6 target area provides access to the PHELIX laser beam and to accelerator hardware (e.g. test beam, RF equipment, diagnostics)
We can provide a versatile testbed to study laser-accelerated particles in conventional accelerator structures

4. Project phases of the core LIGHT project
Post-acceleration structure
Target chamber
Solenoid
Ion beam diagnostic
Debuncher cavity
UNILAC beam
Short pulse diagnostics

5. Contributions / Responsibilities
Helmholtz Institute Jena
Coordination
Development and setup of a 100TW compressor for a 12 cm sub-aperture beam of PHELIX
Short-pulse diagnostics
GSI PHELIX/PP, Acc., Beam Diagnostics, AP
Laser, timing, control system
Beamline to target chamber
Accelerator structures
Proton beam diagnostics
FZ Dresden-Rossendorf
Solenoid for collimation + PSU
TU Darmstadt
PI, Acceleration experiments
Collimation simulations, target development
JWG University Frankfurt
Accelerator structure development

6. Timeline 2010 2011 2012 beyond Compressor setup √ Beamlines √
100 TW pulses in target chamber √
Collimation and ion beam shaping √
Proton pulse diagnostics √
Test of rebuncher structure with UNILAC proton beam √
Injection into rebuncher structure
Injection into post-acceleration structure
Laser acceleration experiments with higher repetition rate at JETI, POLARIS, DRACO and PHELIX
Possibility to inject into SIS 18
Higher repetition rate at Z6
Prepairing a technical design report

7. Ion beam angular distribution
Other studies in the framework of LIGHT Ion beams from engineered laser beams
Ion beam angular distribution
Electron sheath

8. Lower initial ion beam divergence with engineered laser beams
Hollow Beam Project:
Lower TNSA proton divergence by engineering the electron sheath
Achieved by custom continuous phase masks changing the focal spot
intensity (x1018 W/cm2)
Predicted electron sheath
-30
Annular Laser Beam Focus 20
-20 15
-10
Y (micrometers) 10 10 20 5 30
-30
-20
-10 10 20 30
X (micrometers)

9. Modified Laguerre-Gaussian modes have been developed at PHELIX
A helix-type phase mask is inserted in the front end of PHELIX, together with an amplitude mask with a dark spot in the center (singularity)
We simulated the influence of aberrations and phase errors to the focal spot
We optimized the maximum energy (fill factor) and the expected intensity distribution in the far field
Results are used as input for PIC simulations for the proton beam characteristics and choice of the right target foil dimensions.
Input with amplitude mask

10. Preliminary necessary improvements to the PHELIX laser
Optimization of the beam wavefront at the main amplifier input
before
after
Simulation and preliminary tests showed the sensitivity of the beam to aberrations
A dedicated beam time (P041) was used to improve the PHELIX laser beam quality
Measurement of the wave front aberrations at different locations throughout the PHELIX laser chain
Most improvements / changes were done to the Main Amplifier injection and our quasi-deformable double-pass mirror (MM1)
Phase (0.9 l PtV)
Phase (0.2 l PtV)
Far field
Far field
This effect could be seen in the Focal spot quality after the Main Amplifier

11. The control of low-order aberrations allowed to implement hollow beam
The hollow beam propagates through the PHELIX laser chain with the right aperture size for the LIGHT project / 100 TW beam line (12 cm).
Near Field
Far field
Far field
Optimized phase masks also helped for larger apertures, but still room for improvement to match the maximum size of the PW Compressor in the PHELIX hall.
16 cm
Smooth beam with optimized phase mask
Preamplifier output with 16 cm beam
Compressor output with 12 cm beam
The use of adaptive optics is being investigated for higher control levels

12. Our next steps
2D and 3D PIC simulations based on simulated and experimentally verified ion beams
Measurements at the target chamber center (currently not available)
Validation experiments

13. LIGHT coordinates activities in the field of particle acceleration at GSI
LIGHT aims at injecting laser-accelerated ions into conventional accelerator structures
The key factor is the transport of the source peak brilliance
The core LIGHT project is under realization at the Z6 Experiment place of GSI
The principle elements have been demonstrated separately
Integration will happen in 2012
Additional studies are being followed outside the baseline design to improve the setup performance
Reduction of the ion initial divergence by means of engineered laser beams is being investigated
Higher source brilliance via energy-peaked spectral distributions by RPA