1. Ultra-Intense Lasers
Based on K.W.D. Ledingham e.a., Science, 300, 1107 (2003)
Roel Rozendaal

2. Overview Creating ultra-high intensity pulses Applications ~1020 W/cm2
Chirped Pulse Amplification
Applications
Particle Acceleration
Nuclear processes
Umstadter (2003)

3. Chirped Pulse Amplification
Mode-locked laser pulse
Chirping
h(n)  I(n)
Pulse lengthening (fiber)
Group Velocity Dispersion
Amplification
Pulse shortening (prisms/gratings)
Image from wikipedia.org

4. Applications Electron acceleration by laser-induced plasma
Proton beams
Ion beams
Photonuclear activation
Nuclear isomer excitation
Neutron beams

5. Plasmas: Basics High intensities: ionisation
Higher intensities: accelerated electrons
Light pressure  density fluctuations
“Electrostatic wakefield plasma wave”
Umstadter (2003)

6. Plasmas: 200 MeV e- Conventional accelerators: ~55 MV/m
Laser-Plasma based: up to TV/m
Ti:Sapphire 30 fs, 3x1018 W/cm2
Malka (2002)

7. Proton beams Thin foil target “Target Normal Sheath Acceleration”
Ledingham (2005)

8. Proton beam results Up to 58 MeV protons 500 fs, 3x1020 W/cm2
Snavely (2000)

9. Proton beam isotopes 750 fs, 2x1020 W/cm2
(PET-relevant) isotope production:
11B + p  11C
18O + p  18F
Ledingham (2004)

10. LLNL PetaWatt Laser
Image from

11. Ion Beams Coating Proton shielding  heating Up to 5 MeV / nucleon
100 MeV Fluoride (F7+)
Excellent beam quality (collimation)

12. Photonuclear Activation
Thicker target: bremsstrahlung
Transmutation of radioactive isotopes
99Tc, 129I, 135Cs
129I t1/2 = 15.7 million years
128I t1/2 = 25 minutes
Magill (2003)

13. Nuclear Isomers Same nucleus, different energy Excitation mechanisms
10’s of keV - few MeV
Excitation mechanisms
Nuclear Excitation by Electronic Transition (NEET)
Photo-excitation
Electronic excitation
Photon-induced de-excitation
Energy storage: MJ - GJ/g
Walker (1999)
Carroll (2001)

14. Nuclear Isomers: Experiments
181mTa (+6.2 keV) creation (~1016 W/cm2)
Dye-laser, 200 fs
Nd:Glass laser, 1 ps
180mTa + g  180Ta + 75 keV (+ g)
180mTa t1/2  1015 year
180Ta t1/2  8 hours
Bremsstrahlung from conventional accelerator (4 MV)

15. Neutron beams Neutrons from fusion (1970’s)
2H + 2H 3He + n (2.45 MeV)
3H + 2H 4He + n (14.1 MeV)
Spallation: proton bombardment
11B + p  11C + n
Usually heavier metals (zinc, lead)
Emission of ~109 neutrons/shot possible
(1020 W/cm2, 750 fs)