Thomson backscattering in the extended lambda cubed
regime for extension of the available gamma energy
above 100MeV range
D. Ursescu1,*, L.Ionel1, L. Neagu 1
M. Boca2, V. Florescu2
D. Jaroszynski3 and the team
* Horia
Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Magurele, Romania
Institute for Lasers, Plasma and Radiation Physics, (INFLPR), Magurele, Romania
2 Universitatea din Bucuresti, Romania
3 University of Strathclyde, UK
1 National
Gaussian beam complex formalism
Finite difference time
domain
Needed to understand and benchmark the spatial temporal effects in focus
How tight should one focus?
Finite difference time
domain
f-number values for the focusing optics to obtain peak
intensities in the ultra-relativistic regime
Vary the duration and the width of the pulse
mirror
Focal distance
Focal region
We Finite
analyze
two types time
of data:
difference
Temporal
evolution in one point
domain
Spatial distribution at a given moment in time.
Spatial analysis: electric field
τ=2λ; D=30 µm
τ=2λ ; D=150 µm
Tighter focus
Propagation direction
τ=10λ ; D=90 µm
τ=50λ ; D=150 µm
τ=50λ ; D=30 µm
Tighter focus
Shorter pulse !
Laser waist vs oscillation amplitude
The dependence of the Gaussian beam waist (w0) and of the
electron excursion amplitude (aω ) of the obtained peak intensity
Harmonics generation prediction
A. Popa, “Periodicity property of
relativistic Thomson scattering with
application to exact calculations of
angular and spectral distributions of
the scattered field”, Phys. Rev. A 84,
023824 (2011)
The spectrum of the normalized total scattered radiation for
a=65.9. (Ij is the intensity of the jth harmonic radiation).
Experiment proposal set-up
τ=10λ ; D=90 µm
Requirements:
- Electron bunch synchronization with the laser pulse:
resolution several times below the electron bunch duration.
- Highest electron density in a single bunch
- Focus positioning for both laser focus and electron beam
focus with micrometer accuracy.
- gamma radiation detection, up to the 1 GeV range.
- Laser produced electron bunches have to be investigated
separately
Compton backscattering using x-ray lasers for the
extension of the available monochromatic gamma
energy in the 400MeV range
D. Ursescu1,* Romeo Banici1, Razvan Ungureanu1, Gabriel Cojocaru1
* Horia
Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), Magurele, Romania
Institute for Lasers, Plasma and Radiation Physics, (INFLPR), Magurele, Romania
1 National
Experiment proposal set-up
X-ray lasers pumped with 1 long and 2 short
pulses
D. Ursescu, R. Banici, G. Cojocaru, R. Ungureanu, R. Dabu,
INFLPR, Romania
Holger Stiel
Max Born Institut, Germany
The solution:
One long two short pulses (1L2S) pumping
First short, weak pulse: quickly increases the ionization
Second short, strong pulse: heats the plasma
Multiple short pulses generation
We modify CPA system in stretcher
D. Ursescu, et al., J.Opt. Adv. Mat. 2010
Multiple short pulses generation
Non-intrusive method using spectral chirp in stretcher
D. Ursescu, et al., J.Opt. Adv. Mat. 2010
R. Banici, D. Ursescu EPL 2011
Interaction chamber set-up
TEWALAS: Vacuum compressor chamber coupled with
interaction chamber
Focal length
system
measurement
CCD
farfield
Targe
t
cylindric
al lens
ns
laser
pulses
Spheric
al
mirror
fs laser
pulses
Zr X-ray laser
The solution:
One long two short pulses (1L2S) pumping
Long pulse: 360ps, 87 mJ, 2.8 mm x 35 μm;
2.5 · 1011 W/cm2
Short pulse: 1.2ps, 125mJ, 3.1 mm x 25 μm;
1.7 · 1014 W/cm2
Optimization:
Delay LS: 120ps-500ps; depending on target, getting shorter for high Z
Delay SS: 0ps-40ps
SS Energies ratio: 0%-25% in prepulse
Zr XRL @22.02nm
divergence
wavelength
Zr XRL spectral line
Mo XRL @ 18.9nm
Mo XRL spectral line
Pd XRL @ 14.7nm and Ag XRL @ 13.89nm
Pd XRL spectral line
Ag XRL spectral line
Sn XRL @11.9nm
Sn XRL spectral line (265 mJ on target)
1L2S Ag X-ray laser results
8% SS energy split
12ps delay
34nJ/pulse
Efficiency 1.7e-7
… but one should
extract the energy
for plasma
preparation
Outlook
Higher repetition rate XRL (100 Hz)
Test the scalability to shorter wavelengths
Applications using high signal-to-noise 1L2S XRL
0.5 GeV photons production using 1mJ XRL
Thomson backscattering at ELI-NP
Experiment proposal set-up
Experiment types:
- E7 experimental area: gamma beam + multi-PW laser energy
up to few hundreds of Joule for seeded XRL => monochromatic
gamma, intermediate flux
- E4/E5: two laser beams => bunch of laser-accelerated
electrons + pump the seeded XRL => broadband gamma rays
but with higher flux.
- E7: gamma beam + driver laser for the gamma beam (above
150mJ energy, 120Hz), synchronous => Higher repetition rate
gamma source.
Experiment proposal set-up
Requirements:
- Electron bunch synchronization with the laser pulse:
resolution below the electron bunch duration.
- Highest electron density in a single bunch
- Focus positioning for both laser focus and electron beam
focus with micrometer accuracy.
- gamma radiation detection, up to the 1 GeV range.
- Laser produced electron bunches have to be investigated
separately
Thank you for attention
Conclusions
• New pumping method proposed: 1L2S
• It decouples the temperature and ionization dynamics
• New multiple short pulses generation method
• A factor of 5 less energy needed to get gain of 55/cm
• 1L2S Ag XRL: one order of magnitude more intense
ELI-NP Facility
2 lasers, 10 PW each
ELI Nuclear Physics
High rep-rate
laser experiments
Oscillators
+OPCPA preamps
1PW block
Ti:Sapph
Flashlamp based
multi-PW block
Ti:Sapph
Flashlamp based
400mJ/ 10Hz/ <20fs
30J/ 0.1Hz/ <30fs
200J/ 0.01Hz/ <30fs
Oscillators
+ preamps
1PW block
Ti:Sapph
Flashlamp based
multi-PW block
Ti:Sapph
Flashlamp based
Oscillator
+ fiber amplifiers
Photogun Driver
Laser
Combined
laser-gamma
experiments
Interaction Laser
DPSSL 10J/120Hz
Gamma beam
Compton based
0.1% bandwidth
e- accelerator
X-band, 600 MeV
Multi-PW laser
experiments
Gamma
experiments
Generation of gain by collisional excitation in Ni-like systems
Co-like fundamental level
3d94d
lasing
transition
3d94p
fast radiative
decay
3d10
Ni-like fundamental level
Ag X-ray laser simulations:
1L1S vs 1L2S