Enhanced laser-driven ion sources for Firma convenzione nuclear and - PowerPoint PPT Presentation

Department of Energy Enhanced laser-driven ion sources for Firma convenzione nuclear and material science applications Politecnico di Milano e Veneranda Fabbrica del Duomo di Milano Matteo Passoni Politecnico di Milano Aula Magna – Rettorato Mercoledì 27 maggio 2015 Nuclear Photonics, Brasov, 28/06/2018

❑ 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. 2

ERC-2014-CoG No.647554 ERC consolidator grant: 5 year project, from September 2015 to September 2020 Goal : To E xplore the N ew S cience and engineering unveiled by U ltraintense, ultrashort R adiation interaction with matt E r Hosted @ , Department of Energy, Politecnico di Milano Principal investigator: Matteo Passoni Team : PI, 2 Associate Professor, 1 Assistant Professor, 3 Post-Docs, 3 PhDs + master students and support from NanoLab people www.ensure.polimi.it 3

The ENSURE team at Politecnico di Milano Margherita Matteo Passoni Andrea Associate professor Zavelani Pola Associate Associate PI of ENSURE + professor professor ERC-P O C INTER Luca Devid Alessandro Valeria Fedeli Dellasega Maffini Russo Post-doc Post-doc Post-doc Assistant professor Andrea Arianna Francesco Francesca Pazzaglia Mirani Formenti Arioli Master’s PhD PhD PhD student student student student 4

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) 5

Target is the key: Near-critical layer Ultra-short, super-intense Ultra-short, super-intense laser pulse laser pulse micrometric micrometric thick foil thick foil Conventional TNSA Enhanced TNSA ❑ Near-critical layer onto a m m-thick foil M. Passoni et al. Phys Rev Acc Beams 19.6 (2016) 6

Target is the key: Near-critical layer Hot electron Hot electron cloud cloud Conventional TNSA Enhanced TNSA ❑ Near-critical layer onto a m m-thick foil ❑ More and hotter relativistic electrons M. Passoni et al. Phys Rev Acc Beams 19.6 (2016) 7

Target is the key: Near-critical layer Accelerated Ions Accelerated Ions Conventional TNSA Enhanced TNSA ❑ Near-critical layer onto a m m-thick foil The target is the key! ❑ More and hotter relativistic electrons ❑ More ions at higher energy M. Passoni et al. Phys Rev Acc Beams 19.6 (2016) 8

Near-critical targets for laser-driven acceleration I laser =10 20 W/cm 2 E laser = 3 x 10 11 V/m = 50 X E atomic Full ionization Plasma! 𝑜 𝑑 = 𝜌 𝑛 𝑓 𝑑 2 𝑜 𝑑 ≈ 6 mg/cm 3 Plasma critical 𝑓 l 2 (@ l =800 nm) density: n ≈ n c near critical plasma strong laser-plasma coupling n<<n c underdense plasma n>>n c overdense plasma little laser absorption most of laser is reflected n e /n c 0.1 10 100 0.01 1 mg/cm 3 0.6 60 600 0.06 6 9

Ion acceleration @ PULSER (GIST) in collaboration with: I. W. Choi, C. H. Nam et al. Role of target properties (s-pol, ~ 7 J, 3x10 20 Wcm -2 , 30 ° inc. angle) nearcritical foam thickness : Al (0.75 µm) + foam (6.8 mg/cm 3 , 0-36 µm ) 30 5 10 + max energy bare Al H + maximum energy [MeV] 6+ maximum energy [MeV] 160 6+ max energy C 12 m m foam 25 Counts [a.u.] 4 10 8 m m foam 120 20 3 10 80 15 2 10 S polarization (peak intensity) 40 H 10 C 1 10 0 6 12 18 24 30 36 5 10 15 20 25 30 Target thickness [ m m] Energy (MeV) ❑ 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) 10

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/cm 3 , 8 µm) pulse intensity pulse polarization : s, p and circular polarization 35 Al ( 0,75 m m ) Al, p pol. 30 Max proton energy [MeV] Max proton energy [MeV] 8 m m foam Al, s pol. 30 25 Al, c pol. 12 m m foam 25 foam, c pol. 18 m m foam 20 foam, p pol. 36 m m foam 20 foam, s pol. 15 15 10 10 5 5 0 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 20 W/cm 2 ] 20 W/cm 2 ] Intensity on target [10 Intensity on target [10 Dependence on polarization : ➢ foam vs Al: volume vs surface interaction ❑ strong for Al foils ➢ irregular foam surface: polarization definition ❑ reduced for foam targets ➢ role of target nanostructure 11

Ion acceleration @ DRACO 150 TW in collaboration with: (preliminary data!) I. Prencipe, T. Cowan, U. Schram et al. Laser parameters @ Draco (HZDR, Dresden) 30 • Energy on target = 2 J 4 m m C foam on 1.5 m m Al + max. energy [MeV] Intensity = up to 5 x 10 20 W/cm 2 • 25 1.5 m m Al, no foam Angle of incidence = 2 ° • 20 Foam PLD parameters 15 • F = 2.1 J/cm 2 10 • P = 1000 Pa Ar H • d ts = 4.5 cm 5 • Substrate = Al 1.5 µm 30 40 50 60 70 80 90 100 110 • Foam thickness = 4, 8, 12 µm Laser power fraction (%) 10¹² 30 # Particles [1/(MeV*sr)] + max. energy [MeV] Optimal foam 25 10¹¹ thickness 20 10¹⁰ 15 10⁹ 10 H No foam 10⁸ 5 25 30 0 2 4 6 8 10 12 5 10 15 20 Foam thickness [ m m] Energy [MeV] 12

Near-critical targets for laser-driven acceleration I laser =10 20 W/cm 2 E laser = 3 x 10 11 V/m = 50 X E atomic Full ionization Plasma! 𝑜 𝑑 = 𝜌 𝑛 𝑓 𝑑 2 𝑜 𝑑 ≈ 6 mg/cm 3 Plasma critical 𝑓 l 2 (@ l =800 nm) density: n ≈ n c near critical plasma strong laser-plasma coupling n<<n c underdense plasma n>>n c overdense plasma little laser absorption most of laser is reflected n e /n c 0.1 10 100 0.01 1 mg/cm 3 0.6 60 600 0.06 6 C foams : Gas-jets Solids one of the (few) options 13

How to produce C foams: ns Pulsed Laser Deposition (PLD) Laser Beam Plasma l = 266, 532, 1064 nm plume Pulse duration= 7ns Energy= 0.1-2 J Fluence: 0.1 - 20 J/cm 2 Target Max rep. rate= 10 Hz Background Gas • Inert (He, Ar..) Substrate • Reactive (O 2 ) (almost any kind of substrate) target-to-substrate distance Gas pressure Laser fluence “atom by atom” deposition “Nanoparticle” deposition 14

New experimental facilities @ Nanolab Coherent Astrella ™ fs-PLD interaction chamber ❑ Ti:Shappire l =800 nm ❑ PLD mode + Laser processing ❑ up to 4 targets ❑ Ep > 5 mJ ❑ Upstream + downstream pressure control ❑ Pulse duration < 100 fs ❑ Fast substrate heater ❑ Peak Power > 50 GW ❑ Fully automated software ❑ Rep Rate = 1000 Hz 15

New experimental facilities @ Nanolab Hi gh P ower I mpulse M agnetron S puttering (HiPIMS): ❑ Peak power density = 10³ W/cm² ❑ Peak current density = 1 – 10 A/cm² ❑ Two cathodes, multi-elemental targets Laser Pulse ❑ Fully automated software C-foam Combined fs-PLD & HiPIMS deposition fs-PLD Substrate HiPIMS techniques to fully control target preparation ! 16

Foam property control with ns-PLD Micro-scale Macro-scale Nano-scale - Average density - Crystalline structure - Uniformity - Morphology - Composition - Thickness profile …. - Laser Wavelength Laser Fluence Gas pressure Geometry Deposition time ns-PLD process parameters 17

How to produce carbon foams l =532 nm F= 2.1 J/cm 2 d T-S = 4.5 cm 1000 172.4 1 µm 3 ) Density (mg/cm n e /n c 100 17.2 nano-trees 4 µm 4 µm Foams 10 1.7 0 200 400 600 800 1000 A. Zani et al . , Carbon , 56 358 (2013) A. Maffini et al., On the growth dynamics of Pressure (Pa) low-density carbon foams , in preparation I. Prencipe et al., Sci. Technol. Adv. Mater . 16 (2015) 18

Aggregation model to study the foam growth Diffusion-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 19

Particle In Cell (PIC) Simulations Well established and powerful tool to study laser plasma interaction Inclusion of the nanostructure morphology to properly model physical processes • • With homogeneous foam With DLCCA foam L. Fedeli et al. Scientific Reports, volume 8 , Article number: 3834 (2018) 20

Integrated numerical simulation of laser-ion app A novel tool to study laser-driven ion sources for nuclear and material science Monte Carlo DLCCA simulation of foam aggregation simulation (Geant4) of Laser-Driven Ion Beam Analysis (IBA) PIC simulation of laser-matter interaction M. Passoni et al., Scientific Reports (2018), under review 21

Laser-driven Particle Induced X-ray Emission (PIXE) ❑ PIXE: 1) Simulated experiment MeV energy, low current Particle Laser accelerated Ion beam Accelerator proton spectrum ❑ Laser-driven PIXE: E [MeV] ✓ Unconventional features of ion beam (broad spectrum, tunable energy, ns bunch duration) ✓ Cheaper, portable PIXE setup ❑ Commercial codes not ok for laser PIXE ✓ Ad-hoc code developed 3) Sample composition Lead White Concentration [%] Concentration [%] 2) X-ray spectra real Varnish retrived Dedicated software to process Ca x-ray data Fe HgS X-rays energy [keV] 22