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arXiv · 2302.00346

Polarisation Leakage due to Errors in Track Reconstruction in Gas Pixel Detectors

N. Bucciantini·N. Di Lalla·R. W. R. Romani·S. Silvestri·M. Negro·L. Baldini·A. F. Tennant·A. Manfreda
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Abstract

X-ray polarimetry, based on Gas Pixel Detectors (GPDs), have reached a high level of maturity with the Imaging X-ray Polarimeter Explorer (IXPE) leading to the first ever spatially resolved polarimetric measures. However, being this a new technique, a few unexpected effect have emerged during in flight operations. In particular it was almost immediately found that on-board unpolarized calibration sources were showing radially polarized halos. The origin of this features was recognized in a correlation between the error in reconstructing the absorption point of the X-ray photon and the direction of its electric field vector. Here we present and discuss in detail this effect, showing that it is possible to provide a simple and robust mathematical formalism to handle it. We further show its role and relevance for the recent IXPE measures, and for the use of GPD-based techniques in general, and illustrate how to model it in the study of extended sources.

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N. Bucciantini, N. Di Lalla, R. W. R. Romani, S. Silvestri, M. Negro, L. Baldini, A. F. Tennant, A. Manfreda. 2023-02-01. Polarisation Leakage due to Errors in Track Reconstruction in Gas Pixel Detectors. https://doi.org/10.1051/0004-6361%2F202245744

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