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