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T: Fachverband Teilchenphysik

T 99: Methods in Astroparticle Physics IV

T 99.4: Vortrag

Freitag, 4. April 2025, 09:45–10:00, VG 3.101

Position Reconstruction in a Scintillating CeBr3 Crystal for the ComPol CubeSat Using Neural Networks — •Jonas Schlegel — TUM, Muenchen, Deutschland

Compact objects such as Black Hole Binaries represent extreme astrophysical environments with many unresolved questions. Their small size makes them unsuitable for imaging techniques. Precise X-ray spectra and polarization measurements are crucial for understanding their dynamics and geometry. The CubeSat mission ComPol targets the binary system Cygnus X-1, which includes a rotating black hole and a companion star. After In-Orbit Verification (IOV) on the ISS, it will operate in Low Earth Orbit (LEO), performing spectroscopy and polarimetry in the 20-200 keV hard X-ray range.

Polarimetry is based on Compton scattering kinematics in a two-layer detector system. The prototype uses Silicon Drift Detectors (SDD) to determine the recoiling electron’s energy and position, while a CeBr3 scintillator records photon energy via a Silicon Photomultipliers (SiPM) matrix. The core objective is to reconstruct absorbed X-ray events in the calorimeter.

A barium source is used for detector calibration, with scans performed in the X-Y and Y-Z planes. Neural networks achieve position resolutions of 2.4-4.3 mm in the x and y plane and 2.8 mm for the z plane. Edge effects are corrected with position- and energy-dependent shifts. Data from the LARIX X-ray facility validate the expected φ-distribution for unpolarized X-rays, demonstrating the success of the position reconstruction methods.

Keywords: CubeSat; Black Hole Binary; Scintillator; Neural Networks