English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The Wide Field Imager (WFI) flying on Athena will usher in the next era ofstudying the hot and energetic Universe. WFI observations of faint, diffusesources will be limited by uncertainty in the background produced byhigh-energy particles. These particles produce easily identified "cosmic-raytracks" along with signals from secondary photons and electrons generated byparticle interactions with the instrument. The signal from these secondaries isidentical to the X-rays focused by the optics, and cannot be filtered withoutalso eliminating these precious photons. As part of a larger effort tounderstand the WFI background, we here present results from a study ofbackground-reduction techniques that exploit the spatial correlation betweencosmic-ray particle tracks and secondary events. We use Geant4 simulations togenerate a realistic particle background, sort this into simulated WFI frames,and process those frames in a similar way to the expected flight and groundsoftware to produce a WFI observation containing only particle background. Thetechnique under study, Self Anti-Coincidence or SAC, then selectively filtersregions of the detector around particle tracks, turning the WFI into its ownanti-coincidence detector. We show that SAC is effective at improving thesystematic uncertainty for observations of faint, diffuse sources, but at thecost of statistical uncertainty due to a reduction in signal. If sufficientpixel pulse-height information is telemetered to the ground for each frame,then this technique can be applied selectively based on the science goals,providing flexibility without affecting the data quality for other science. Theresults presented here are relevant for any future silicon-based pixelatedX-ray imaging detector, and could allow the WFI and similar instruments toprobe to truly faint X-ray surface brightness.

Mitigating the effects of particle background on the Athena Wide-Field Imager