Backscattered electron emission after proton impact on gold nanoparticles with and without polymer shell coating

Félicien Hespeels, Anne-Catherine Heuskin, Tijani Tabarrant, Emanuele Scifoni, Michael Kraemer, Gregoire Chêne, David Strivay, Stephane Lucas

Research output: Contribution to journalArticle

Abstract

This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra were collected over a 0 to 1000 eV energy range using a Retarding Field Analyzer. This paper presents the spectra obtained for proton beam energies of 0.5 and 2 MeV and diameter 2.5 and 3.8 nm GNPs. The spectra were also measured for 3.8 nm GNPs after 5 and 10 MeV proton irradiations. GNPs were deposited on a 100 nm carbon film. Each experimental spectrum was compared with dedicated simulations based on existing numerical models used in the TRAX and Geant4 Monte Carlo codes. 
 For 100 nm carbon target, good agreement between experimental, TRAX and Geant4 simulation results can be observed.
 For 3.8 nm GNPs, the TRAX simulations reproduce with good agreement the electron energy spectra produced after 0.5, 2, 5 and 10 MeV proton irradiations, while Geant4 spectra display a lower secondary electron yield at low energy (<600eV) for all the studied energies. This underestimation can mostly be explained by the 790 eV threshold applied in the condensed history model used by Geant4 which impacts the secondary electron energy distribution. Results obtained for carbon and gold targets highlight the impact of the secondary electron production threshold for proton ionization process considered in condensed history models.
 The experimental results demonstrate that the single interaction approach used in TRAX is adapted to reproduce secondary electron emission from GNPs. On the other hand, the standard electron generation threshold implement in G4BetheBlochModel and G4BraggModel condensed-history models used in Geant4 is not adapted to reproduce low energy electron emission in gold targets.
 Finally, the results highlight that the GNP coating leads to a decrease of the electron yield and mostly affects low energy electrons (<500eV) emitted from GNPs.&#13.

Original languageEnglish
JournalPhysics in Medicine and Biology
Volume64
Issue number12
DOIs
Publication statusPublished - 2019

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Gold
Nanoparticles
Protons
Polymers
Electrons
Carbon
History

Keywords

  • proton beam
  • gold nanoparticle
  • PPAA
  • electron emission
  • TRAX
  • Geant4
  • MonteCarlo

Cite this

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title = "Backscattered electron emission after proton impact on gold nanoparticles with and without polymer shell coating",
abstract = "This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra were collected over a 0 to 1000 eV energy range using a Retarding Field Analyzer. This paper presents the spectra obtained for proton beam energies of 0.5 and 2 MeV and diameter 2.5 and 3.8 nm GNPs. The spectra were also measured for 3.8 nm GNPs after 5 and 10 MeV proton irradiations. GNPs were deposited on a 100 nm carbon film. Each experimental spectrum was compared with dedicated simulations based on existing numerical models used in the TRAX and Geant4 Monte Carlo codes. For 100 nm carbon target, good agreement between experimental, TRAX and Geant4 simulation results can be observed. For 3.8 nm GNPs, the TRAX simulations reproduce with good agreement the electron energy spectra produced after 0.5, 2, 5 and 10 MeV proton irradiations, while Geant4 spectra display a lower secondary electron yield at low energy (<600eV) for all the studied energies. This underestimation can mostly be explained by the 790 eV threshold applied in the condensed history model used by Geant4 which impacts the secondary electron energy distribution. Results obtained for carbon and gold targets highlight the impact of the secondary electron production threshold for proton ionization process considered in condensed history models. The experimental results demonstrate that the single interaction approach used in TRAX is adapted to reproduce secondary electron emission from GNPs. On the other hand, the standard electron generation threshold implement in G4BetheBlochModel and G4BraggModel condensed-history models used in Geant4 is not adapted to reproduce low energy electron emission in gold targets. Finally, the results highlight that the GNP coating leads to a decrease of the electron yield and mostly affects low energy electrons (<500eV) emitted from GNPs.&#13.",
keywords = "proton beam, gold nanoparticle, PPAA, electron emission, TRAX, Geant4, MonteCarlo",
author = "F{\'e}licien Hespeels and Anne-Catherine Heuskin and Tijani Tabarrant and Emanuele Scifoni and Michael Kraemer and Gregoire Ch{\^e}ne and David Strivay and Stephane Lucas",
note = "{\circledC} 2018 Institute of Physics and Engineering in Medicine.",
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doi = "10.1088/1361-6560/ab195f",
language = "English",
volume = "64",
journal = "Physics in Medicine and Biology",
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Backscattered electron emission after proton impact on gold nanoparticles with and without polymer shell coating. / Hespeels, Félicien; Heuskin, Anne-Catherine; Tabarrant, Tijani; Scifoni, Emanuele; Kraemer, Michael; Chêne, Gregoire; Strivay, David; Lucas, Stephane.

In: Physics in Medicine and Biology, Vol. 64, No. 12, 2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Backscattered electron emission after proton impact on gold nanoparticles with and without polymer shell coating

AU - Hespeels, Félicien

AU - Heuskin, Anne-Catherine

AU - Tabarrant, Tijani

AU - Scifoni, Emanuele

AU - Kraemer, Michael

AU - Chêne, Gregoire

AU - Strivay, David

AU - Lucas, Stephane

N1 - © 2018 Institute of Physics and Engineering in Medicine.

PY - 2019

Y1 - 2019

N2 - This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra were collected over a 0 to 1000 eV energy range using a Retarding Field Analyzer. This paper presents the spectra obtained for proton beam energies of 0.5 and 2 MeV and diameter 2.5 and 3.8 nm GNPs. The spectra were also measured for 3.8 nm GNPs after 5 and 10 MeV proton irradiations. GNPs were deposited on a 100 nm carbon film. Each experimental spectrum was compared with dedicated simulations based on existing numerical models used in the TRAX and Geant4 Monte Carlo codes. For 100 nm carbon target, good agreement between experimental, TRAX and Geant4 simulation results can be observed. For 3.8 nm GNPs, the TRAX simulations reproduce with good agreement the electron energy spectra produced after 0.5, 2, 5 and 10 MeV proton irradiations, while Geant4 spectra display a lower secondary electron yield at low energy (<600eV) for all the studied energies. This underestimation can mostly be explained by the 790 eV threshold applied in the condensed history model used by Geant4 which impacts the secondary electron energy distribution. Results obtained for carbon and gold targets highlight the impact of the secondary electron production threshold for proton ionization process considered in condensed history models. The experimental results demonstrate that the single interaction approach used in TRAX is adapted to reproduce secondary electron emission from GNPs. On the other hand, the standard electron generation threshold implement in G4BetheBlochModel and G4BraggModel condensed-history models used in Geant4 is not adapted to reproduce low energy electron emission in gold targets. Finally, the results highlight that the GNP coating leads to a decrease of the electron yield and mostly affects low energy electrons (<500eV) emitted from GNPs.&#13.

AB - This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra were collected over a 0 to 1000 eV energy range using a Retarding Field Analyzer. This paper presents the spectra obtained for proton beam energies of 0.5 and 2 MeV and diameter 2.5 and 3.8 nm GNPs. The spectra were also measured for 3.8 nm GNPs after 5 and 10 MeV proton irradiations. GNPs were deposited on a 100 nm carbon film. Each experimental spectrum was compared with dedicated simulations based on existing numerical models used in the TRAX and Geant4 Monte Carlo codes. For 100 nm carbon target, good agreement between experimental, TRAX and Geant4 simulation results can be observed. For 3.8 nm GNPs, the TRAX simulations reproduce with good agreement the electron energy spectra produced after 0.5, 2, 5 and 10 MeV proton irradiations, while Geant4 spectra display a lower secondary electron yield at low energy (<600eV) for all the studied energies. This underestimation can mostly be explained by the 790 eV threshold applied in the condensed history model used by Geant4 which impacts the secondary electron energy distribution. Results obtained for carbon and gold targets highlight the impact of the secondary electron production threshold for proton ionization process considered in condensed history models. The experimental results demonstrate that the single interaction approach used in TRAX is adapted to reproduce secondary electron emission from GNPs. On the other hand, the standard electron generation threshold implement in G4BetheBlochModel and G4BraggModel condensed-history models used in Geant4 is not adapted to reproduce low energy electron emission in gold targets. Finally, the results highlight that the GNP coating leads to a decrease of the electron yield and mostly affects low energy electrons (<500eV) emitted from GNPs.&#13.

KW - proton beam

KW - gold nanoparticle

KW - PPAA

KW - electron emission

KW - TRAX

KW - Geant4

KW - MonteCarlo

U2 - 10.1088/1361-6560/ab195f

DO - 10.1088/1361-6560/ab195f

M3 - Article

VL - 64

JO - Physics in Medicine and Biology

JF - Physics in Medicine and Biology

SN - 0031-9155

IS - 12

ER -