Geant4 simulation of the residual background in the ATHENA Wide Field Imager from protons deflected by the Charged Particle Diverter

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F22%3APU147315" target="_blank" >RIV/00216305:26620/22:PU147315 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1117/12.2629994" target="_blank" >http://dx.doi.org/10.1117/12.2629994</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1117/12.2629994" target="_blank" >10.1117/12.2629994</a>

Result language

angličtina

Original language name

Geant4 simulation of the residual background in the ATHENA Wide Field Imager from protons deflected by the Charged Particle Diverter

Original language description

X-ray telescopes opened up a new window into the high-energy universe. However, the last generation of these telescopes encountered an unexpected problem: their optics focused not only X-rays but low-energy (so called soft) protons as well. These protons are very hard to model and can not be distinguished from X-rays. For example, 40% of XMM-Newton observations is significantly contaminated by soft proton induced background flares. In order to minimize the background from such low-energy protons the Advanced Telescope for High ENergy Astrophysics (ATHENA) satellite introduced a novel concept, the so called Charged Particle Diverter (CPD). It is an array of magnets in a Hallbach design, which deflects protons below 76 keV before they would hit the Wide Field Imager (WFI) detector. In this work, we investigate the effect of scattering of the deflected protons with the CPD walls and the inner surfaces of the WFI detector assembly. Such scattered protons can loose energy, change direction and still hit the WFI. In order to adopt the most realistic instrument model, we imported the CAD model of both the CPD and the WFI focal plane assembly. Soft protons corresponding to similar to 2.5 hours of exposure to the L1 solar wind are simulated in this work. The inhomogeneous magnetic field of the CPD is included in the simulation. We present a preliminary estimate of the WFI residual background induced by soft proton secondary scattering, in the case of the optical blocking filter present in the field of view. A first investigation of the volumes responsible for scattering the protons back into the field of view is reported.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

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OECD FORD branch

20304 - Aerospace engineering

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Proceedings of SPIE

ISBN

978-1-5106-5344-3

ISSN

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e-ISSN

—

Number of pages

9

Pages from-to

„“-„“

Publisher name

SPIE-INT SOC OPTICAL ENGINEERING

Place of publication

BELLINGHAM

Event location

Montreal

Event date

Jul 17, 2022

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000865607100098