Peter G. Thirolf, LMU München The ‘Fission–Fusion‘ Reaction Mechanism: The ‘Fission–Fusion‘ Reaction Mechanism: Using dense laser-driven ion beams Using dense laser-driven ion beams for nuclear astrophysics for nuclear astrophysics Outline: motivation: nucleosynthesis of heavy elements r process path: waiting point N=126 ultra-dense laser-accelerated ion beams novel reaction mechanism: fission-fusion experimental requirements at ELI-NP Peter G. Thirolf, LMU Munich ELI-NP Workshop, Bucharest, March 10-12, 2011
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Peter G. Thirolf, LMU München The ‘Fission–Fusion‘ Reaction Mechanism: Using dense laser-driven ion beams for nuclear astrophysics for nuclear astrophysics.
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Peter G. Thirolf, LMU München
The ‘Fission–Fusion‘ Reaction Mechanism:The ‘Fission–Fusion‘ Reaction Mechanism:Using dense laser-driven ion beamsUsing dense laser-driven ion beams
for nuclear astrophysicsfor nuclear astrophysics
Outline: motivation: nucleosynthesis of heavy elements r process path: waiting point N=126
ultra-dense laser-accelerated ion beams novel reaction mechanism: fission-fusion
experimental requirements at ELI-NP
Peter G. Thirolf, LMU Munich
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
r process: waiting point r process: waiting point N=126N=126
- waiting point N=126: bottleneck for nucleosynthesis of actinides- last region of r process ‘close’ to stability
r process: - path for heavy nuclei far in ‚terra incognita‘ - astrophysical site(s) still unknown: core collapse SN II, neutron star merger ?
Au, Pt, Ir,Os
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
- cold compression of electron sheet, followed by electron breakout
laser acceleration (300 J, ~10%): normal stopping reduced stopping
232Th 1.2 . 1011 1.2 . 1011
C 1.4 . 1011 1.4 . 1011
protons 2.8 . 1011 1.8 . 1011
beam-like light fragments 3.7 . 108 1.2 . 1011
target-like light fragments 3.2 . 106 1.2 . 1011
fusion probability 1.8 . 10-4 1.8 . 10-4
FL(beam) + FL (target)
neutron-rich fusion products 1.5 4 . 104
(A≈ 180-190) laser development in progress: diode-pumped high-power lasers: increase of repetition rate expected
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
Towards N=126 Waiting Towards N=126 Waiting PointPoint
r process path: - known isotopes ~15 neutrons away from r process path (Z≈ 70)
0.5 0.1x
visions:- test predictions: r process branch to long-lived (~ 109 a) superheavies (Z≥110) search in nature ?- improve formation predictions for U, Th- recycling of fission fragments in (many) r process loops ?
- lifetime measurements: already with ~ 10 pps
measure: - masses, lifetimes, structure --delayed n emission prob. P,n
0.001fisfus
key nuclei
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
Experimental layoutExperimental layout
high powershort-pulselaser APOLLON
(gas-filled) separator
mirrortarget
concreteshielding
characterization of reaction products - decay spectroscopy
(tape) transport system
detector
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
Experimental layoutExperimental layout
high powershort-pulselaser APOLLON
(gas-filled) separator
mirrortarget
concreteshielding
gas stopping cellcooler/buncher
Penning trapmass measurements (m/m= 10-8)
characterization of reaction products - decay spectroscopy
precision mass measurements: e.g. Penning trap
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
““The Way Ahead”The Way Ahead”
ELI-NP Workshop, Bucharest, March 10-12, 2011
exploratory experiments :
requirements:
- RPA target chamber - 232Th target development - ion diagnostics: Thomson parabola
- staged approach with tests of crucial ingredients at existing facilities prior to operation of ELI-NP
laser ion acceleration of Th ions collective effects of dense ion bunches (range enhancement)
Peter G. Thirolf, LMU München
ConclusionsConclusions
novel laser ion acceleration (RPA):
- generation of ultra-dense ion bunches - enables fission-fusion reaction mechanism fusion between 2 neutron-rich fission fragments - reduction of electronic stopping ? - may lead much closer towards N=126 r-process waiting point
ELI-NP: unique infrastructure
- superior to ‘conventional’ radioactive beam facilities
The Way Ahead:
- exploratory experiments at existing laser beams (Thorium acceleration, collective range enhancement..) - collaboration has to be formed
ELI-NP Workshop, Bucharest, March 10-12, 2011
Peter G. Thirolf, LMU München
Thanks to the Collaboration:Thanks to the Collaboration: