monoenergetic proton beams from laser driven shocks dan haberberger neptune laboratory, department...
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Monoenergetic Proton Beams from Laser Driven
Shocks
Dan HaberbergerNeptune Laboratory, Department of Electrical Engineering, UCLA
In collaboration with:Sergei Tochitsky, Chao Gong, Warren Mori, Chan Joshi
Neptune Laboratory, Department of Electrical Engineering, UCLA
Frederico Fiuza, Luis SilvaInstituto Superior Technico, Lisbon, Portugal
Outline
AAC (Jun 2012)Neptune Laboratory
• Applications of Laser Driven Ion Acceleration (LDIA) : Hadron cancer therapy• Localized energy deposition : Bragg Peak• Therapy centers : conventional accelerators vs. lasers• Ion source requirements
• Collisionless Shock Wave Acceleration (SWA) of protons• 1D OSIRIS Simulations• Laser driven case
• UCLA proton acceleration experiment : CO2 laser and a H2 gas jet target• Results : Spectra, emittance• Interferometry : Plasma density profile
• 2D OSIRIS simulations• Modeling the experiment• Scaling to higher power lasers• Using 1µm laser systems
• Conclusion
Laser Driven Ion Beam ApplicationsProbing of strong electric fields in dense plasma on the picosecond timescale
– ~1μm resolution, 5-20MeV– Borghesi, Phys. Plasmas (2002)• 50μm Ta wire• Imaging with 6-7MeV protons
-15ps -5ps 5ps
VULCAN Laser, 20J, 1019W/cm2
Hadron Cancer Therapy– 250MeV, 109-1010 protons/s– ΔE/E ≤ 5%
Fast Ignition– 15-23MeV– <20ps– Eff = 10%
Picosecond injectors for conventional accelerators– 1-10MeV, <.004 mm.mrad, <10-4 eV.s [Cowan, Phys. Rev. Lett. (2004)]
AAC (Jun 2012)Neptune Laboratory
Markus RothWG6 : Tuesday 1:30
Energy Deposition : Ions vs. Photons
AAC (Jun 2012)Neptune Laboratory
Bragg Peak for ions results in localized energy deposition
Multi-beam Localization
Radiation dose relative to peak (100%)
Simulations of Irradiating the Human Skull
GSI Helmholtz Centre for Heavy Ion Research in Darmstadt http://www.weltderphysik.de/gebiet/leben/tumortherapie/warum-schwerionen/
AAC (Jun 2012)Neptune Laboratory
Problem : Cost and Size
Heidelberg Ion-Beam Therapy Center, Commissioned in 2009
Cost : ~200 Million USD• Accelerator ring (20m)• Transport magnets• Complicated Gantry• Radiation shielding
Only a few in operation along with ~30 small facilites• 10’s of thousands of people
treated• Need more than an order of
magnitude more therapy centers
20 meters
http://www.klinikum.uni-heidelberg.de/Welcome.113005.0.html?&L=1AAC (Jun 2012)Neptune Laboratory
25 meters
Solution : Laser Based Accelerators
Goal Cost : 10-20 million USDTable top laser system (developing)Transportation : MirrorsOnly has focusing magnet Gantry : small, protons generated in direction of patient
M. Murakami, et al., AIP Conf. Proc. 1024 (2008) 275, doi:10.1063/1.2958203
AAC (Jun 2012)Neptune Laboratory
Proton Beam Requirements
Radiation Beam Requirements
2 Gray in 1 liter tumor in a few minutes-Translates to 1010 protons per second
Proton energies in range of 250 MeV
Energy Spread of ~5%
Focusability, Energy Accuracy, Energy Variability, Dose Accuracy, etc.
Lasers can accelerate up to 1012 protons in a single shot
Worlds most powerful lasers have produced 75 MeV protons
Vast majority of beams have continuous energy spread
Future Work
Laser Driven Ion Acceleration (LDIA)
AAC (Jun 2012)Neptune Laboratory
Dose
Energy
EnergySpread
What is a Shock Wave?
Subsonic Sonic Supersonic
A disturbance that travels at supersonic speeds through a medium
• At supersonic speeds, pressure will build at the front of a disturbance forming a shock
• Characterized by a rapid change in pressure (density and/or temperature) of the medium
In a plasma, a shock wave is characterized by a propagating electric field at speeds useful for ion acceleration (Vsh > 0.01c)
AAC (Jun 2012)Neptune Laboratory
1D OSIRIS Simulations
Plasma 1ne1
Te
Cold Ions
Plasma 2ne2
Te
Cold Ions
In Plasmas, the driver is a potential or electric field
Plasma 1ne1 = ne2
Te1
Cold Ions
Plasma 2ne1 = ne2
Te1
Cold Ions
Expansion Shocks Driven Shocks
Ambipolar electric field of Plasma 1 is driven into
Plasma 2
Initial drift causes overlap; overlap causes local density
increase and again ambipolar electric field is driven into the
plasma
←Vd /2Vd /2→
AAC (Jun 2012)Neptune Laboratory
1D Sims : Driven Shocks (Te = 511 keV Cs = 0.0233c).
Wave train response
Proton trapping begins
Proton reflection begins
Strong damping of wave
No interaction
Reflection Conditioneɸ > 1/2mv2
AAC (Jun 2012)Neptune Laboratory
Shock formation in laser driven plasmas
• Linearly polarized laser incident upon an overcritical target creates and heats the plasma
• Ponderomotive force creates density spike and imparts a velocity drift on surface plasma
High-intensitylaser pulse E
Shockacceleration
Sheath Field (TNSA)
Beam quality destroyed by TNSA fields
F. Fiuza | Prague, April 20 | SPIE 2011
Denavit PRL 1992, Silva PRL 2004
AAC (Jun 2012)Neptune Laboratory
• Gas jets can be operated at or above 1019 cm-3 (ncr for 10µm)
• Long scale length plasma on the back side of the gas jet inhibits strong TNSA fields preserving proton spectrum
• High repetition rate source• Clean source of ions (H2, He, N2,
O2, Ar, etc…)• Low plasma densities allows for
probing of plasma dynamics using visible wavelengths
Gas jet target advantages for Shock Wave Acceleration (SWA)
CR-39Nuclear Track
Detectors
CO2 Laser Interacting with a Gas Jet Target
Gas plume
hybrid PICExtended PlasmaSteepened
PlasmaE TNSA ~ 1/L
AAC (Jun 2012)Neptune Laboratory
120µm
1mm
IL = 5x1016 W/cm2
Interferometry1ps 532nm
CO2 Laser Pulse Temporal Structure
Pressure = 8atmLine Separation = 55GHz
Line Center : 10.6µm
400 450 500 550 6000
1
2
3
4MARS Shot # 14300
Peak P
ower (
TW)
Time (ps)300 400 500 600
0
0.5
1
1.5
2
2.5
MARS Shot # 14405
Peak P
ower (
TW)
Time (ps)
~70ps ~110ps
D. Haberberger et al., Opt. Exp. 18, 17865 (2010)
AAC (Jun 2012)Neptune Laboratory
Experimentally Measured Temporal ProfileCalculated CO2 Gain Spectrum
E = 50 JPpeak = 4TW
Pulse Separation = 1/55GHz = 18.5ps7-10 pulses long
18.5ps
~70ps
3ps
27 27.5 28 28.50
0.2
0.4
0.6
0.8
1
Norma
lized A
mplitu
de
Frequency (THz)
Frequency Spectrum
CO2 Gain Spectrum at 8atm
3ps Input Pulse SpectrumOverlapped Spectrums
0 50 100 150 2000
0.2
0.4
0.6
0.8
1
Time (ps)
Amplified PulseTemporal Structure
18ps = 1/55GHz
3ps
1.2THz
55GHz
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 660
0.2
0.4
0.6
0.8
1
Distance (mm)
dE/d
x (N
orm
aliz
ed U
nits
)
Energy Deposition of Protons in CR-39 vs. Distance
1mm CR-39
CR-39 Proton Detection
CR-391mm
Detection:11-15 MeV
CR-391mm
Detection:16-19 MeV
CR-391mm
Detection:20-22 MeV
CR-391mm
Detection:23-25 MeV
150mm100x100mm Imaging Proton
Spectrometer
Protons10μm Laser Pulse
CR-391mm
Detection:<1-10 MeV
1 MeV27 MeV
AAC (Jun 2012)Neptune Laboratory
CO2 Laser Produced Proton Spectra
1mm CR-39
Energy spreads measured to
be FWHM ΔE/E 1% ̴�
Feb 22th
CR-39 #179Jan 25th
CR-39 #92Jan 25th
CR-39 #99 Haberberger, Tochitsky, Fiuza, Gong, Fonseca, Silva, Mori, Joshi, Nature Phys., 8, 95-99 (2012)
Noise Floor
AAC (Jun 2012)Neptune Laboratory
Emittance Estimation
Source Size : d = 120µmBeam Size (RMS) : σx 5.7mm ) σy 2.2mm )Divergence : θx 37mrad ) θy 14mrad )Emittance : εx = d.θx = 4.6mm.mrad εy = d.θy = 1.7mm.mrad
H2 Gas Jet
CR-39150mm
Laser
Protons
50mm
50mm
σy
σx11/30/1022MeV
AAC (Jun 2012)Neptune Laboratory
Plasma Density Profile
-600 -400 -200 0 200 4000
1
2
3
4
X-Distance (m)
Pla
sma
Den
sity
(10
19cm
-3)
Y-D
ista
nce
( m
)
-600
-300
0
300
600
Laser
LaserObservations1. Strong profile
modification on the front side of the plasma : hole boring
2. Sharp rise (10λ) to overcritical plasma where laser pulse is stopped
3. Long (1/e 30λ) exponential plasma tail
AAC (Jun 2012)Neptune Laboratory
2D OSIRIS Simulations : Input Deck
linear ramp
exponential ramp(plasma expansion)
18 ps
Initial Plasma Profile
Laserao = 2.5Δτ = 3ps
Laserao = 2.5Δτ = 3ps
AAC (Jun 2012)Neptune Laboratory
2D OSIRIS Simulations : Results Time = 17ps Time = 52ps Time = 122ps
2D Simulations : Energy Scaling
UCLA
AAC (Jun 2012)
-K. Zeil et. al., New J. Phy 12, 045015 (2010)
𝐸𝑝∝𝑎𝑜3 /2
Proposed Shock Wave Acceleration at 1µm
Gas plume
hybrid PICExtended Plasma
E TNSA ~ 1/L
AAC (Jun 2012)Neptune Laboratory
10µm Laser – Gas Jet Target 1µm Laser – Exploded Foil Target
High Power Drive Pulse
Low PowerPre-heater
Foil target of thickness Δx
Ion beam
Δt
Δx and Δt • Peak density for Drive Pulse is 5-15ncr
= 5-15 x 1021 cm-3 • Extended plasma profile (1/e - 30λ)
ConclusionsLaser-driven, electrostatic, collisionless shocks in overdense plasmas
produce monoenergetic protons at high energies• Protons accelerated to 15-22 MeV (at IL ~ 4x1016 W/cm2)• Energy spreads as low as 1% (FWHM)• Emittances as low as 2x4 mm·mrad• Interferometry uncovers unique plasma profile• Plasma simulations elucidate shock wave acceleration of
protons through the backside of the plasma
AAC (Jun 2012)Neptune Laboratory
Step towards achieving 200-300 MeV protons needed for cancer therapy
• Simulations show scaling to ~300 MeV with a laser ao = 15
• Proposed method of exploding foil target for 1µm laser systems
Supporting Simulated Interferogram
Measured Plasma Profile
Simulated Plasma Profile
-600 -400 -200 0 200 4000
1
2
3
4
X-Distance (m)
Pla
sma
Den
sity
(10
19cm
-3)
AAC (Jun 2012)Neptune Laboratory
1μm Nd:GlassCPA System
10μm TEA MasterOscillator
8atm Regenerative
Amplifier2.5atm
Large ApertureFinal Amplifier
3ps, 3mJ
500ns30mJ 3ps
~nJ
3ps4mJ3ps
350mJ
3ps 100J
CS2 Kerr Cell
Low Pressure CO
2 Amplifier
Neptune CO2 MOPA Laser System
AAC (Jun 2012)Neptune Laboratory
1μm Glass CPA System
1μm GlassMaster
Oscillator
1μm GlassRegenerative
Amplifier
Grating
Grating
Grating
Stretcher
Compressor
500fs100mW
~1ns70mW
~1ns4mJ
3ps3mJ
5Hz
110MHz
CS2 Kerr SwitchingCS2 Kerr CellPolarizer Analyzer1µm from CPA
10µm from MO
10µm1µm3ps 500ns
30mJ1mJ3ps1nJ
10µm• I90°(1µm) = 25 GW/cm2
• Signal-to-background contrast = 105
10µm Seed Production
AAC (Jun 2012)Neptune Laboratory
100Jwo = 6.5cm
I = 30-140 GW/cm2
P = 1-15 TW
• Pressure : 2.5atm• Δνpressure = 14GHz• go = 2.6%/cm
3-Pass Final Amplifier
4mJwo = 0.5cm
I = 200 MW/cm2
350mJwo = 1cm
I = 4 GW/cm2
20x35cm
L = 2.5m
Haberberger, Tochitsky, Joshi, Optics Exp., 18, 17865-17875 (2010)
50 100 150 200 250 3000
0.2
0.4
0.6
0.8
1
Pulse train afterRegenerative Amplification
Norma
lized A
mplitud
e
Time (ps)180 200 220 240
0
0.2
0.4
0.6
0.8
1
Pulse train afterFinal Amplification
Norma
lized A
mplitud
e
Time (ps)
goL = 19.5
18ps
45J, 3ps15TW
400 450 500 550 6000
1
2
3
4MARS Shot # 14300
Peak P
ower (
TW)
Time (ps)300 400 500 600
0
0.5
1
1.5
2
2.5
MARS Shot # 14405
Peak P
ower (
TW)
Time (ps)
~70ps ~110ps
100J
Final Amplification
AAC (Jun 2012)Neptune Laboratory
Specs and Results 10µm Pulse Measurement
4mJ
8atm CO2 moduleΔνp = 37GHz
~nJ
50% OC
CS2 Kerr Cell
Streak Camera
10µm
Red DiodeLaser
0 20 40 60 80 100 120 140 160-0.2
0
0.2
0.4
0.6
0.8
Time (ps)
No
rmaliz
ed
Am
plit
ude
18ps ~3.3ps
2 22
16ln 2 ln0 o
en enr
Gz
Regenerative Amplification
Cross Polarizers
AAC (Jun 2012)Neptune Laboratory
LDIA Experimental Setup F=1.5 → 2wo = 120μm
H2 Gas Jet
Laser TransmissionDiagnostic
Stack of CR-39Nuclear Detector
To Streak Camera Diagnostic
Laser ReflectionDiagnostic
Protons
NaCl
CO2 Laser50J, 3ps pulse trainDiameter = 10cm
Picosecond Probe
AAC (Jun 2012)Neptune Laboratory