Carpathian Summer School, Sinaia, Romania 2012
The Futureof Laser Nuclear Physics
Ken Ledingham
SUPA, Dept of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland & AWE plc Aldermaston, Reading, RG7
4PR,
Over the last 10 years my group and now the SUPA group working with Klaus
Spohr have worked on what we call “Laser Induced Nuclear
Physics”-
What is this?
What are the Laser Driven Nuclear Reactions?
• Gamma induced fission
• Gamma and proton cross sections
• Laser produced neutron activation analysis
• Photon and charged particle production of radio-active isotopes including PET isotopes
• Laser production of monoenergetic protons
VULCAN petawatt laser (RAL)
Energy 600 J (on target)Repetition 1 hourWavelength 1.05 mPulse duration 0.6 ps Intensity ~6x1020 Wcm-2 Maximum pulsesper week ~25
Petawatt with Extensive Nuclear Shielding
Nuclear beams generated by an intense laser beam (Ulrich Schramm)
CPA pulse
Altarget
CCD camera
Protons
Cu activation stack Cu activation stack
“BLOW-OFF”DIRECTION
“STRAIGHT THROUGH”DIRECTION
Protons
Proton spectra using activation techniques
Proton Spectra from 100TW
In front of target– “blow-off”
direction
5 cm
5 cm
BACK
5 cm
5 cm
Behind the target –“straight through”
direction
FRONT
Monoenergetic Protons from Mass Limited
Targets
Experimental Arrangement
Multi Channel Plates
Laser Irradiation of DOT Targets
Simulation of the experiment2D-PIC simulation for following conditions:
IL= 3 1019 W/cm2, 5 µm Ti-foil + 0.5 µm PMMA dot (20 20) µm2
0.2 0.4 0.6 0.8 1 2 4
1E7
1E8
deu
tero
ns (
(20
keV
sr)
-1)
energy (MeV)
drop21053f
First „Monoenergetic“ Proton Beams from isolated water droplets
Ti-Sa laser pulse:
40 fs, 21019 W/cm2, contrast 10-8
forward Protons :
Thomson spectrometer20
Important: laser pulse shape and target structure
Mass Limited Cone Targets
Kirk Flippo, Tom Cowan et al
Snow Targets
Laser Irradiation of Snow targets
Laser Wakefield Acceleration of
Electrons
Electron acceleration in a capillary discharge waveguide
Waveguide:Guiding of 40 TW laser pulses:• in capillary discharge waveguide• over 33 mm of plasma
Input spot Exit spot
Electron acceleration: Generation of e-beams with:• %-level energy spread• mrad divergence• Energy up to 1 GeV
Lawrence Berkeley National Lab:W. Leemans, B. Nagler, C. Tóth,K. Nakamura, C. Geddes, E. Esarey,C. SchroederOxford University:S. M. Hooker and A. J. Gonsalves
Applications of Laser Driven
Particle Beams
PET Isotope Production
Laser Beam
Laser driven PET isotope production
Irradiance (Wcm-2m2)
1019 1020 1021
Act
ivity
(B
q)
102
103
104
105
106
107
108
109
1010
Activity as a function of laser intensity. The black and red hatched areas are for typical
patient doses for 18F and 11C
Laser-driven photo-transmutation of 129I – a long lived nuclear waste product
• 129I has a half-life of 15.7 x 106 years
• 128I has a half-life of 25 mins
• The transmutation was carried out using a laser driven (, n) reaction
Nuclear activation: Experiment arrangement
Activation samples
Resistively heated target
Iodine samples
Laser pulse
(,n) reaction in 129I using a Ge detector to measure decay of 128I
The Generation of Gamma ray light sources
• First of all you require GeV electron beams generated by lasers or by conventional linacs
• Compton backscatter laser photons to produce multi-MeV gamma ray beams.
Time
IR-electron bunch collision
A Z
Last x-rays of collision produced when bunches separate.
Electron bunchIR bunch
x-rays =
electrons
A
First x-rays of collision produced when bunches 1st meet.
ZA
X-rays A through Z travel at c with electron bunch.
Courtesy George Neil, JLab
Peak brilliance of light sources with star of GRLS at 1MeV 15 orders of magnitude greater than all synchrotrons and FELS
Gamma Ray Light Sources (GRLS)
NUCLEAR Applications of Intense Gamma Ray
Beams – Nuclear resonance Fluorescence
GRLS)
Gamma ray resonant fluorescence
Mainland security
Nuclear waste reclassification
Storing radioactive waste at power stations
There are hundreds of thousands of such barrels world wide with very little knowledge of the contents. GRLSs would enable certifiable classification of the waste contents
Depository of hundreds of drums of radioactive waste
Nuclear Resonance Fluorescence Example of NRF spectra obtained from a plutonium target.
Level Scheme for Pu 239
Nuclear Physics at High Temperatures
This is a nuclear regime which is best carried out using lasers - opportunities
at XFEL and ELI Bucharest
At present there is no laser induced reaction which cannot
be done better using conventional accelerators –
at high temperatures this could be very different
What do we intend to do at high temperatures – modification of the half
life of 26Al using the high temps produced by
coincident laser driven particle beams
How do we make the Al26 -use the PW short pulse laser to generate a proton beam and
then use a Mg26(p,n)Al26reaction
Simultaneously heating with a laser produced gamma ray beam or thus a Mg26(pγ,n)Al26 reaction
Al26 Decay scheme
Motivation• 26Al in the astrophysical context using a gamma camera• • 1809 keV line in Galaxy
Interstellar abundance
Level scheme
Evolution of stellar abundance
Skelton R et. al., Phys.Rev. C35(1),45,1987
NASA Compton Gamma Ray observatory (COMPTEL) 1991-2000 & Plüschke S et al., arXiv:astro-ph/0104047v1
Voss R et al., Astronomy & Astrophysics, 504, 531, 2009
Schematic of laser plasma nuclear 26Al experiment
Edriver
~15J
Use the NIF PW laser at 1022 W/cm2 or VULCAN
ShieldingCanvas
DiamondTarget
26Mg
p
TSNAI~1018-20 Wcm-2
'p-productionpulse'
High temperature production pulse(hard photon beam)
NaI or Ge
ORGAM Detector System
Laser Induced Fission of 238U and Nuclear Fission Yields as a Fn of Temp
Front Al-sheet 1thickness: 10μmisochoric heated
Back Al-sheet 2thickness:10μm
depleted 238Uthickness: 8μmencapsulated by Al-foilsProton beam
0-40μmvariable
Laser
Al-production target
~200μm
isochoric heated volume
Fission products & trajectories
Cu-stack
Al-U-Al sandwich target
This was an experiment to be carried out using short pulse laser isochoric heating but could be done by NIF heating
Nuclear Excitation in Plasmas NEET/NEEC
Nuclear Opportunities at XFEL 2015 and ELI
Thank you for listening
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