SMuK 2023 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 98: Gas-Detecors, Detector Systems

T 98.1: Vortrag

Mittwoch, 22. März 2023, 17:30–17:45, WIL/C207

X-ray Polarimetry with GridPixes — Klaus Desch, •Markus Gruber, and Jochen Kaminski — Physikalisches Institut, Universität Bonn

In astrophysics and material science on synchrotron light sources the measurement of X-ray polarisation can be an useful instrument. Therefore, a direct measurement would be beneficial. It can be directly measured by tracking photoelectrons created in photoelectric interactions. This is possible because their emission angle depends on the direction of the electric field vector of the photons. Within a gaseous detector these electrons have a sufficiently long mean free path such that tracking is possible - if the granularity of the readout is high enough. For this a GridPix - a combination of a Timepix(3) ASIC with 55 µ m pixel pitch and a photolithographically postprocessed amplification stage (integrated grid) can be used. Within the GridPix the holes of the grid are perfectly aligned with the pixels. Thus, it is possible to detect the avalanches of individual primary electrons.

The talk will focus on the working principle and the design of a GridPix based X-ray polarimeter. Based on testbeam data taken at PETRA III and simulations the performance of the detector at different X-ray energies as well as the dependence on different detector parameters like gas choice and geometry will be discussed. Additionally challenges and possible improvements of such a detector will be presented.