the libra project: progress in source development and radiobiology applications
DESCRIPTION
The LIBRA project: progress in source development and radiobiology applications. M.Borghesi. Centre for Plasma Physics, School of Mathematics and Physics. The Queen’s University of Belfast. Meeting on Laser-Plasma accelerators, Imperial College, 13 December 2012. Contributors. - PowerPoint PPT PresentationTRANSCRIPT
The LIBRA project: progress in source development and radiobiology applications
M.Borghesi
The Queen’s University of Belfast
Centre for Plasma Physics, School of Mathematics and Physics
Meeting on Laser-Plasma accelerators, Imperial College, 13 December 2012
Contributors
S. Kar, D. Doria, R. Prasad, K.F. Kakolee, K. Quinn, B. Ramakrishna, G. Sarri, B. Qiao,
M.Geissler, M. Zepf, Centre for Plasma Physics, Queen’s University Belfast,
J.Kavanagh, G. Schettino, K. Prise,
Centre for Cancer Research and Radiation Biology, Queen’s University Belfast
D. Neely, D. Carroll, J. Green STFC-Rutherford Appleton Laboratory,
P .McKenna, X. Yuan, University of Strathclyde,
Z.Najmudin, N.Dover, C. Palmer, J Schreiber Imperial College,
F. Fiorini, D.Kirby, S. Green, University of Birmingham,
M. Merchant, C.J.Jeynes, K.Kirkby, University of Surrey,
M. Cherchez, J. Osterholtz, O. Willi, Heinrich Heine University Dusseldorf,
A. Macchi, University of Pisa
Laser Induced Beams of Radiation and their Applications
Basic Technology programme, 2007-2012
Collaboration
LIBRA
STFC
NPL
Project aimed to develop target, detector and interaction technology required for high repetition, high energy operation of radiation sources.
Outline
• Current properties of laser-ion beams
• Proposed applications/requirements • Current research applications:
• Radiobiology
• Future applications: cancer therapy
• Prospects for energy increase• Radiation Pressure Acceleration
VULCANEnergy : up to 500 J (on target)Wavelength : 1.05 mPulse duration : 0.5 ps Intensity : ~1-5 1020 Wcm-2 Repetition : 8 to 10 shots / day
Petawatt-class laser systems at the CLF, RAL
GEMINI Laser, CLF, RAL: E ~ 12 J , = 0.8 µm, = 50 fsFocal spot : 5 µm FWHM Intensity~ 1021 W/cm2
Rep rate : 1- 10 second
Sheath acceleration: ion beam properties
• Low emittance: rms emittance < 0.01 mm-mrad • Short duration source: ~ 1 ps (Et < 10-6 eV-s) • High brightness: 1011 –1013 protons/ions in a single shot (> 3 MeV)• High current (if stripped of electrons): kA range
• Divergent (~ 10s degrees)• Broad spectrum• Maximum energies: ~ 70 MeV
• Scaling: E ~ (Il2) 0.5
Ion beam from TARANIS facility, QUB
E ~10 J on target in 10 µm spot
Intensity: ~1019 W/cm2, duration : 500 fs
Target: Al foil 10um thickness
Prospective applications of laser-driven ion acceleration
Radiography (density measurements)
Deflectometry (field measurements)
Isochoric heating of matter
Neutron production
Material studies (Irradiation)
Radiobiology
Cancer therapy
Production of isotopes for PET
Fusion Energy (Fast Ignition)
Nuclear/particle physics applications
150-250 MeVprotonsCarbon ions at 2-4 GeV
Energies >GeV(high repetition)
Applications already activewith TNSA beams
What would ion beam users require ?
• Wide energy and fluence range ✔• Different ion species ✔• Homogeneous transverse beam distribution ✔• Stability in terms of energy/fluence distribution• Variable beam spot size• Beam control (diagnostic/dosimetry) within 5% error• High repetition
Beamline approach (ELIMED beamline, Prague)
Unique to laser-driven beams:Ultrashort particle burst duration (ps at sources)Ultrahigh dose rate (> 109 Gy/s)
Charged particle therapy of cancer
Ballistic advantages
Biological advantages
Ions permit precise targeting of the tumor,minimizing the dose deposition in healthy tissues
Large number of direct DNA damage. More effective in destroying radioresistant tumours (particularly with Carbon)
Compared to conventional x-ray radiotherapy:
Hadrontherapy centres worldwide are limited in number
• 8 in the USA• 6 in Japan• 12 in Europe/Russia• 3 in China, Korea, South Africa• 1 in UK ( Clatterbridge, limited to 60 MeV)
Only 3 facilities use Carbon ions
2 protontherapy trial centres currently being developed in the UK(active by 2017, UCLH London, Christie Hospital Manchester).
There is need for developing alternative approaches to hadrontherapy which may in future, help the treatment becoming more widespread / more efficient.
Very high cost: >£ 100 M for protons, >£ 250 M for proton+CarbonSignificant fraction of costs: transport/delivery systems (up to 50-70%)
Reduced cost/shielding/size: • possibility to avoid/reduce size of gantry• laser transport rather than ion transport (vast reduction in radiation shielded space)
Flexibility:• Possibility of controlling output energy and
spectrum• Possibility of varying accelerated species(H, C , but also intermediate species)
Novel therapeutic/diagnostic optionsMixed fields: x-ray + ions , multiple beamsIn-situ diagnosis
High dose rates effects
Laser-driven ions: a source for future radiotherapy?
Several projects worldwide:
SAPHIR (France)FDZ Dresden/ MPQ (Germany)ELIMED (Cz)Fox Chase Centre (USA)
• Compared to conventional accelerators what do we need to improve?
- Narrow angular distribution– Narrow energy distribution
(not simply slicing)– Beam purity– High repetition, stability– Higher endpoint energy
Radiobiology experiments
We carried out tests of biological effectiveness oflaser-driven ions on V79 cells by using the TARANIS laser at QUB
Main aims:• establish a protocol for proton irradiation
compatible with a laser-plasma environment• establish a procedure for on-shot dosimetry• Demonstrate dose-dependent cell damageon single exposure, high dose irradiations• test for any deviation from known results using
conventional sources
Previous work :S. Yogo et al, APL, 98, 053701 (2011)S.D. Kraft et al, NJP, 12, 085003 (2010)
Chinese hamster(Cricetulus griseus) TARANIS proton spectrum
Dose of ~ 1-10 Gy is delivered in several fractionsEach fraction has a short duration – 10 nsBut effective dose rate ~ Gy/s – Gy/min
Dispersion: in 20mm from 3MeV to 10MeV
Energy Res.: ~ 2 MeV energy overlapping (500um slit)
Delivered dose @ 1-5MeV: ~ few Gy/shot
Proton beam characteristics at cell plane
50 um Mylar window
Focusing Parabola
Laser Beam Slit (500 µm)Target
0.9 T magnet
SN
Setup for cell irradiation
Vacuum chamber Wall
D
Mylar window : 50 µm
1 cm
D ~ 27 cm
1 cm
Cell Irradiation Protocol for clonogenic assay
Energy
Shadows of the cell dots
Chinese Hamster Cell culture Sample preparation
Cell IrradiationPost-irradiation processingColony formation
Single shot survival curve!
Cell damage investigated at ultrahigh dose rates (> 109 Gy/s)
RBE10 estimated at ~1.4In line with “standard” results with V79 cellse.g. Folkard et al, (1996) – Same RBE with LET=17.8 Kev/µm
SF comparable with literature data at similar dose and energy but longer pulses
Higher dose/dose rates obtainable with beam colllimation, or low dispersionmagnetic systems
D.Doria et al, AIP Advances 2, 011209 (2012)
Future tests: DNA damage, higher LET ions,Effects of oxygen depletion
Enhanced options offered by access to CLF lasers (GEMINI experiment scheduled in summer 2013)
High efficiency producton of H and C beams from ultrathin foils (e.g. 25 nm at 5 1020 W/cm2)
• Radiation pressure acceleration• Hole boring • Relativistic transparency/
Break out afterburner C.A. Palmer et al, Phys. Rev. Lett, 106, 014801 (2011)
D. Haberberger et al, Nat Phys, 8.95 (2012)
A. Henig, et al, Phys. Rev. Lett. 103, 045002 (2009)
D. Jung et al, Phys. Rev. Lett.,107, 115002 (2011)
Shock acceleration
Radiation pressure acceleration Light Sail
Ion energy increase: several emerging mechanisms are being explored (besides TNSA optimization)
Radiation Pressure on thin foils - light sail
• Cyclical re-acceleration of ions • Narrow-band spectrum (whole-foil acceleration) • Fast scaling with intensity
e-Z+
€
FR = (1+ R)A IL
c
€
⇒ v i =(1+ R)τminid
IL
c∝ Iτη −1
η = minid Areal density
Issues at present intensities• Competition with TNSA• Hot electron heating cause foil disassembly(ultrathin foils are needed for moderate a0)
€
W ~ IL τ η( )2
T.Esirkepov, et al. Phys. Rev. Lett., 92, 175003 (2004)O.Klimo et al, Phys. Rev. ST, 11, 031301 (2008)APL Robinson et al, NJP, 10, 013021 (2009)A.Macchi, S. Veghini, F. Pegoraro, Phys. Rev. Lett. , 103, 085003 (2009)
Scaling decreases for relativistic ions : linear scaling with I for vi~ c
PIC investigations of Radiation Pressure Acceleration(Light Sail regime)
B. Qiao et al, Phys Rev Lett,102,145002 (2009)
Generally unstable at lower intensities, but:2-species targets lead to stabilized acceleration of lighter species already at ~1020 W/cm2.
B. Qiao et al, Phys Rev. Lett., 105, 1555002 (2010)B.Qiao, et al, Phys. Plasmas, (2011)
2D PIC ILLUMINATION code
Condition for stability of Light Sail identified (smooth transition between hole boring and light-sail phase,GeV protons at > 1022 W/cm2)
LIBRA campaigns at the CLF, RAL
VULCAN Petawatt
Pulse duration ~ 750 fs
Energy on target up to 200 J
Intensity up to 3 x 1020 W/cm2
Scans made by varying :• Laser Intensity, polarisation• Target density, thickness
Typical feature from ultrathin foils: Co-moving ions of diff e/m
100nm Cu; Linear Pol; I = 3 x 1020 W/cm2
Solid line: TP1 (laser axis)Dotted line: TP2 (13o off axis)
1 1010000000000
100000000000
1000000000000
10000000000000
Energy/nucleon (MeV)dN
/dE
(in /
MeV
/Sr)
50nm Cu; Cirular Pol; I = 1.5 x 1020 W/cm2
e/m = 1e/m = 0.5e/m = 0.42
Hybrid regime where RPA cohexists with TNSA
No significant dependence on polarization
2D PIC, multilayer, multispeciesDensity profile at two different times
Cu
C
p
S. Kar et al, Phys. Rev. Lett, 109, 185006 (2012)
Scaling of carbon peak with Light sail parameter
€
a02 dt η( )
2
Energy of peak scales ~
€
I τ η( )2
Henig, PRL (2009)
S. Kar et al, Phys. Rev. Lett, 109, 185006 (2012)
€
I τ η( )
€
I τ η( )2
Conversion efficiency into peak ~ 1%
Scaling highly promising for achieving high Ion energies
101 102 103 104100
101
102
103
a02tp/c
Ion
ener
gy (
MeV
/nuc
leon
) Eion (a02tp/c)2
Incr
ease
Flu
ence
, or,
Dec
reas
e c
Red dots: 2D and 3D results from multispecies simulations of stable RPA taken from literature
Inset : PIC simulation scaled up from VULCAN data (2 X I, 1/2.5 target areal density)
45 fs @ 5x1020 W/cm2
450 fs @ 5x1019 W/cm2
€
I τ η( )
Similar spectra and scaling in GEMINI results – (Similar intensities but shorter pulses)
GEMINI data : Laser parameters : 50 fs, 6 J , 1-5 10 20 W/cm2
Targets : Carbon (amorphous), density: 2g/cc, thickness: 10-100 nm
Only lightest species shows peaks – not bulk componentOnset of target transparency for the thinnest targets?
C - 25 nm
PIC syms
Conclusions
Some of present applications of laser-driven ions exploit unique and distinctive
properties of laser-ion beams (short duration, low emittance, small source):
proton radiography/deflectometry, Warm dense matter studies
Real time material damage studies, Ultra-high dose rate radiobiology
Applications currently covered by conventional accelerators (e.g. cancer therapy)
require a marked improvement of parameters for laser-drivers to be competitive:
Compactness Is a clear advantage, but improvements are required in terms of energy,
flux, etc.., but also high-average power, towards a beamline approach.
Radiation Pressure Acceleration is emerging from experiments, and promising for
future delivery of pulses at high flux and high energies (medical energies and beyond)
The LIBRA project: progress in source development and radiobiology applications
X-Rays Protons
Orbital Rhabdomyosarcoma
Courtesy T. Yock, N. Tarbell, J. Adams
ILLUMINATION 2D PIC code (M. Geissler)
• Stable acceleration requires smooth transitionbetween “hole boring” phase and LS phase
RP in phase 1: 2I/c Χ (1-vb/c)/(1+vb/c) RP in phase 2: 2I/c Χ (1-vi/c)/(1+vi/c)
• Need to drive target quite “hard” to achieve a highhole-boring velocity (vb~c) before transition
B. Qiao et al, Phys Rev Lett,102,145002 (2009)
Radiation pressure acceleration in the light sail mode: GeV energies at 1022 W/cm2
30 nc
Unstable case
ILLUMINATION PIC code (M. Geissler, QUB)
Unstable caseA.P.L. Robinson et al, NJP (2009)
Rayleigh TaylorinstabilityF. Pegoraro, S.V. BulanovPRL (2007)
100 nc
5 1022 W/cm2
In multi-species targets the acceleration of the lighter species is inherently more stable
• Target: electron density ne0=200nc, thickness l0=8nm<ls C6+ and H+ : nic0=32.65 nc, nip0=4.1nc with nic0:nip0=8:1
I0 ~ 51019W/cm2, 40 laser cycles, l= 1 µm
the proton layer moves ahead of the C6+ layer.
Debunching of the electron layer - complete separation of the C6+ and proton layers. Strong electron leakage
Electrons
H+
C6+
B. Qiao et al, Phys Rev Lett , 105, 1555002 (2010)
The C6+ layer has insufficient charge-balancing electrons- Coulomb explosion
Proton layer is surrounded by an excess number of electrons--->Stable RPA!!