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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4

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: matteo.passoni@polimi.it