Reducing the Athena WFI Background with the Science Products Module: Results from Geant4 Simulations
Abstract
The Wide Field Imager (WFI) on ESA's Athena X-ray observatory will include the Science Products Module, a secondary CPU that can perform special processing on the science data stream. Our goal is to identify on-board processing algorithms that can reduce WFI charged particle background and improve knowledge of the background to reduce systematics. Telemetry limitations require discarding most pixels on-board, keeping just candidate X-ray events, but information in the discarded data may be helpful in identifying background events masquerading as X-ray events. We present an analysis of Geant4 simulations of cosmic ray protons interacting with the structures aboard Athena, producing signal in the WFI from a variety of secondary particles with various types of particle tracks. We search for phenomenological correlations between these particle tracks and detected events that would otherwise be categorized as X-rays, and explore ways to exploit these correlations with efficient algorithms to flag or reject such events on-board. In addition to possibly reducing the Athena instrumental background, these results are applicable to understanding the particle component in any X-ray silicon-based detector in space. We gratefully acknowledge support from NASA grant NNX17AB07G, administered by Penn State, and from NASA contracts NAS 8-37716 and NAS 8-38252 to MIT.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23315812M