Publication detail

Athena charged particle diverter simulations: effects of micro-roughness on proton scattering using Geant4

Breuer, JP. Galgoczi, G. Fioretti, V. Zlamal, J. Liska, P. Werner, N. Santin, G. Boudin, N. Ferreira, I. Guainazzi, M. von Kienlin, A. Lotti, S. Mineo, T. Molendi, S. Perinati, E.

Original Title

Athena charged particle diverter simulations: effects of micro-roughness on proton scattering using Geant4

Type

conference paper

Language

English

Original Abstract

The last generation of X-ray focusing telescopes operating outside the Earth's radiation belt discovered that optics were able to focus not only astrophysical X-ray photons, but also low-energy heliophysical protons entering the Field of View (FOV). This "soft proton" contamination affects around 40% of the observation time of XMMNewton. The ATHENA Charged Particle Diverter (CPD) was designed to use magnetic fields to move these soft protons away from the FOV of the detectors, separating the background-contributing ions in the focused beam from the photons of interest. These magnetically deflected protons can hit other parts of the payload and scatter back to the focal plane instruments. Evaluating the impact of this secondary scattering with accurate simulations is essential for the CPD scientific assessment. However, while Geant4 simulations of grazing soft proton scattering on X-ray mirrors have been recently validated, the scattering on the unpolished surfaces of the payload (e.g. the baffle or the diverter itself) is still to be verified with experimental results. Moreover, the roughness structure can affect the energy and angle of the scattered protons, with a scattering efficiency depending on the specific target volume. Using Atomic Force Microscopy to take nanometer-scale surface roughness measurements from different materials and coating samples, we use Geant4 together with the CADMesh library to shoot protons at these very detailed surface roughness models to understand the effects of different material surface roughnesses, coatings, and compositions on proton energy deposition and scattering angles. We compare and validate the simulation results with laboratory experiments, and propose a framework for future proton scattering experiments.

Keywords

Particle Scattering; Proton simulations; Scanning Probe Microscopy; Geant4; Surface Roughness

Authors

Breuer, JP.; Galgoczi, G.; Fioretti, V.; Zlamal, J.; Liska, P.; Werner, N.; Santin, G.; Boudin, N.; Ferreira, I. ; Guainazzi, M.; von Kienlin, A. ; Lotti, S.; Mineo, T.; Molendi, S.; Perinati, E.

Released

17. 7. 2022

Publisher

SPIE-INT SOC OPTICAL ENGINEERING

Location

BELLINGHAM

ISBN

978-1-5106-5344-3

Book

Proceedings of SPIE

Pages count

12

URL

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/12181/2630076/Athena-charged-particle-diverter-simulations--effects-of-micro-roughness/10.1117/12.2630076.short?SSO=1

BibTex

@inproceedings{BUT182354,
  author="Breuer, JP. and Galgoczi, G. and Fioretti, V. and Zlamal, J. and Liska, P. and Werner, N. and Santin, G. and Boudin, N. and Ferreira, I. and Guainazzi, M. and von Kienlin, A. and Lotti, S. and Mineo, T. and Molendi, S. and Perinati, E.",
  title="Athena charged particle diverter simulations: effects of micro-roughness on proton scattering using Geant4",
  booktitle="Proceedings of SPIE",
  year="2022",
  volume="12181",
  pages="12",
  publisher="SPIE-INT SOC OPTICAL ENGINEERING",
  address="BELLINGHAM",
  doi="10.1117/12.2630076",
  isbn="978-1-5106-5344-3",
  url="https://www.spiedigitallibrary.org/conference-proceedings-of-spie/12181/2630076/Athena-charged-particle-diverter-simulations--effects-of-micro-roughness/10.1117/12.2630076.short?SSO=1"
}