Firma convenzione
Politecnico di Milano e Veneranda Fabbrica
del Duomo di Milano
Aula Magna – Rettorato
Mercoledì 27 maggio 2015
Enhanced laser-driven ion sources for nuclear and material science applications
Matteo Passoni
Politecnico di Milano
Nuclear Photonics, Brasov, 28/06/2018
Department of Energy
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❑ Largest university of engineering, architecture and design in Italy.
❑ More than 40000 students, ~1400 academic staff, 900 doctoral students
❑ 32 BSc, 34 MSc, 18 PhD programmes.
ERC consolidator grant: 5 year project, from September 2015 to September 2020
Principal investigator:
Matteo Passoni
ERC-2014-CoG No.647554
Hosted @ , Department of Energy, Politecnico di Milano
Goal: To Explore the New Science and engineering unveiled by Ultraintense, ultrashort Radiation interaction with mattEr
Team: PI, 2 Associate Professor, 1 Assistant Professor, 3 Post-Docs, 3 PhDs + master students and support from NanoLab people
www.ensure.polimi.it
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The ENSURE team at Politecnico di Milano
ERC-POC INTER
Matteo PassoniAssociate professor
Margherita
Zavelani
Associate
professor
Andrea
Pola
Associate
professor
Luca
Fedeli
Post-doc
DevidDellasegaPost-doc
Valeria
Russo
Alessandro
Maffini
Post-doc
Andrea PazzagliaPhD student
Arianna FormentiPhD student
Francesco Mirani PhD student
Francesca ArioliMaster’s student
PI of ENSURE +
Assistant
professor
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ENSURE: Main fields of research
Theoretical & experimental investigation of laser-driven ion acceleration
Advanced target production
(low-density foams & multilayer targets)
for laser-plasma interaction experiments
Application of laser-driven ion acceleration
in material & nuclear fields
(e.g. Compact neutron sources, Laser-driven Ion Beam Analysis)
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Target is the key:
Conventional TNSA Enhanced TNSA
Ultra-short, super-intense
laser pulse
Ultra-short, super-intense
laser pulse
micrometric
thick foil
micrometric
thick foil
Near-critical layer
❑ Near-critical layer onto a mm-thick foil
M. Passoni et al. Phys Rev Acc Beams 19.6 (2016)
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Target is the key:
Hot electron
cloud
Hot electron
cloud
Conventional TNSA Enhanced TNSA
Near-critical layer
❑ Near-critical layer onto a mm-thick foil
❑ More and hotter relativistic electrons
M. Passoni et al. Phys Rev Acc Beams 19.6 (2016)
Conventional TNSA
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Target is the key:
Accelerated
Ions
Accelerated
Ions
❑ Near-critical layer onto a mm-thick foil
❑ More and hotter relativistic electrons
❑ More ions at higher energy
Enhanced TNSA
Near-critical layer
M. Passoni et al. Phys Rev Acc Beams 19.6 (2016)
The target is the key!
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Near-critical targets for laser-driven acceleration
Plasma critical density:
𝑛𝑐 =𝜋 𝑚𝑒𝑐
2
𝑒 l2𝑛𝑐 ≈ 6mg/cm3
(@ l=800 nm)
n>>nc overdense plasmamost of laser is reflected
n<<nc underdense plasmalittle laser absorption
n ≈ nc near critical plasmastrong laser-plasma coupling
Ilaser=1020 W/cm2 Elaser = 3 x 1011 V/m = 50 X Eatomic Full ionization Plasma!
0.6 6000.06mg/cm3
ne/nc0.1 1 10 1000.01
6 60
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Ion acceleration @ PULSER (GIST)in collaboration with: I. W. Choi, C. H. Nam et al.
5 10 15 20 25 3010
1
102
103
104
105
Counts
[a.u
.]
Energy (MeV)
bare Al
12 mm foam
8 mm foam
0 6 12 18 24 30 36
10
15
20
25
30
C6
+ m
axim
um
ene
rgy [
MeV
]
H+ m
axim
um
ene
rgy [
MeV
]
Target thickness [mm]
H+ max energy
C6+
max energy
S polarization (peak intensity) 40
80
120
160
Role of target properties (s-pol, ~ 7 J, 3x1020 Wcm-2, 30° inc. angle)
nearcritical foam thickness: Al (0.75 µm) + foam (6.8 mg/cm3, 0-36 µm)
❑ There is an optimum in near critical layer thickness
❑ Maximum proton energy enhanced by a factor ~ 1.7
❑ Number of proton enhanced by a factor ~ 7 M. Passoni et al., Phys. Rev. Accel. Beams 19, (2016)
I. Prencipe et al., Plasma Phys. Control. Fus. 58 (2016)
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0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5
0
5
10
15
20
25
30
Ma
x p
roto
n e
ne
rgy [
Me
V]
Intensity on target [1020
W/cm2]
Al, p pol.
Al, s pol.
Al, c pol.
foam, c pol.
foam, p pol.
foam, s pol.
0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5
5
10
15
20
25
30
35
Ma
x p
roto
n e
ne
rgy [
Me
V]
Intensity on target [1020
W/cm2]
Al ( 0,75 mm)
8 mm foam
12 mm foam
18 mm foam
36 mm foam
Ion acceleration @ PULSER (GIST)in collaboration with: I. W. Choi, C. H. Nam et al.
Role of pulse properties Al (0.75 µm) + foam (6.8 mg/cm3, 8 µm)
pulse intensitypulse polarization: s, p and circular polarization
❑ strong for Al foils❑ reduced for foam targets
Dependence on polarization:➢ foam vs Al: volume vs surface interaction
➢ irregular foam surface: polarization definition
➢ role of target nanostructure
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30 40 50 60 70 80 90 100 110
5
10
15
20
25
30
H+ m
ax.
en
erg
y [
Me
V]
Laser power fraction (%)
4 mm C foam on 1.5 mm Al
1.5 mm Al, no foam
• F = 2.1 J/cm2
• P = 1000 Pa Ar
• dts= 4.5 cm
• Substrate = Al 1.5 µm
• Foam thickness = 4, 8, 12 µm
Laser parameters @ Draco (HZDR, Dresden)
Ion acceleration @ DRACO 150 TWin collaboration with:I. Prencipe, T. Cowan, U. Schram et al.
0 2 4 6 8 10 125
10
15
20
25
30
H+ m
ax. energ
y [M
eV
]
Foam thickness [mm]
No foam
Foam PLD parameters
(preliminary data!)
• Energy on target = 2 J• Intensity = up to 5 x 1020 W/cm2
• Angle of incidence = 2°
Optimal foam thickness
# P
art
icle
s [1
/(M
eV
*sr)
]
5 10 15 20 25 30Energy [MeV]
10¹⁰
10¹¹
10⁹
10⁸
10¹²
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Near-critical targets for laser-driven acceleration
Plasma critical density:
𝑛𝑐 =𝜋 𝑚𝑒𝑐
2
𝑒 l2𝑛𝑐 ≈ 6mg/cm3
(@ l=800 nm)
n>>nc overdense plasmamost of laser is reflected
n<<nc underdense plasmalittle laser absorption
Gas-jets Solids
n ≈ nc near critical plasmastrong laser-plasma coupling
Ilaser=1020 W/cm2 Elaser = 3 x 1011 V/m = 50 X Eatomic Full ionization Plasma!
0.6 6000.06mg/cm3
C foams:one
of the (few)
options
ne/nc0.1 1 10 1000.01
6 60
How to produce C foams: ns Pulsed Laser Deposition (PLD)
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Gas pressureLaser fluence
Substrate
Plasma
plume
target-to-substrate distance
Laser Beam
Background Gas
• Inert (He, Ar..)
• Reactive (O2)(almost any kind of substrate)
“atom by atom” deposition “Nanoparticle” deposition
Target
l= 266, 532, 1064 nm
Fluence: 0.1 - 20 J/cm2
Max rep. rate= 10 Hz
Pulse duration= 7ns
Energy= 0.1-2 J
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New experimental facilities @ Nanolab
fs-PLD interaction chamber Coherent Astrella ™
❑ Ti:Shappire l=800 nm
❑ Ep > 5 mJ
❑ Pulse duration < 100 fs
❑ Peak Power > 50 GW
❑ Rep Rate = 1000 Hz
❑ PLD mode + Laser processing
❑ up to 4 targets
❑ Upstream + downstream pressure control
❑ Fast substrate heater
❑ Fully automated software
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New experimental facilities @ Nanolab
High Power Impulse Magnetron Sputtering (HiPIMS):
❑ Peak power density = 10³ W/cm²
❑ Peak current density = 1 – 10 A/cm²
❑ Two cathodes, multi-elemental targets
❑ Fully automated software
Combined fs-PLD & HiPIMS deposition
techniques to fully control target preparation!
C-foam
Substrate
Laser Pulse
fs-PLD
HiPIMS
Foam property control with ns-PLD
Nano-scale Micro-scale Macro-scale
- Crystalline structure- Composition
- Average density- Morphology- ….
- Uniformity- Thickness profile
ns-PLD process parameters
Laser Wavelength Laser Fluence Gas pressure Geometry Deposition time
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How to produce carbon foams
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0 200 400 600 800 1000
10
100
1000
De
nsity (
mg
/cm
3)
Pressure (Pa)
1.7
17.2
172.4
ne/n
c
4 µm
4 µm
1 µm
l=532 nmF= 2.1 J/cm2
dT-S= 4.5 cm
Foams
nano-trees
A. Zani et al., Carbon, 56 358 (2013)
I. Prencipe et al., Sci. Technol. Adv. Mater. 16 (2015)
A. Maffini et al., On the growth dynamics of
low-density carbon foams, in preparation
Aggregation model to study the foam growthDiffusion-Limited Cluster-Cluster Aggregation (DLCCA):
1) Brownian motion of particles
2) Particle aggregation in clusters by irreversible sticking
3) Clusters deposition on substrate
Real Foam Simulated Foam
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Particle In Cell (PIC) Simulations
• With homogeneous foam • With DLCCA foam
Inclusion of the nanostructure morphology to properly model
physical processes
Well established and powerful tool to study laser plasma interaction
L. Fedeli et al. Scientific Reports, volume 8, Article number: 3834 (2018)
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A novel tool to study laser-driven ion sources for nuclear and material science
Integrated numerical simulation of laser-ion app
Monte Carlo
simulation (Geant4) of
Laser-Driven Ion
Beam Analysis
(IBA)
PICsimulation of laser-matterinteraction
DLCCA simulation of foam
aggregation
M. Passoni et al., Scientific Reports (2018), under review
Ca
Fe
Varnish
Lead White
HgS
Concentration [%]
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Laser-driven Particle Induced X-ray Emission (PIXE)
Laser accelerated
proton spectrum
2) X-ray spectra
3) Sample composition
1) Simulated experiment❑ PIXE:
❑ Commercial codes not ok for laser PIXE
❑ Laser-driven PIXE:✓ Unconventional features of ion
beam (broad spectrum, tunable
energy, ns bunch duration)
✓ Cheaper, portable PIXE setup
E [MeV]
X-rays energy [keV]
Dedicated
software to process
x-ray data
Concentration [%]real
retrived
✓ Ad-hoc code developed
Ion beamParticle
Accelerator
MeV energy,
low current
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❑ Compact neutron sources for material characterization
• fast-neutron spectroscopy
• neutron radiography
❑ Preliminary studies with coupled PIC - Monte Carlo simulations
❑ Strong collaboration with industrial partners
❑ See Maffini (P39), Mirani (P46) posters! A. Tentori, MSc thesis in Nuclear Engineering (2018)
F. Arioli, MSc in Nuclear Engineering, in preparation
ERC-2016-PoC No.754916
INTER
Towards portable neutron sources
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Preliminary announcement of the 4th Targetry Workshop
ENSURE, ERC-2014-CoG No.647554
Monday 10th - Wednesday 12th, June 2019
Politecnico di Milano, Milano, Italy Contact: [email protected]