تقرير
Systematic effects on a Compton polarimeter at the focus of an X-ray mirror
| العنوان: | Systematic effects on a Compton polarimeter at the focus of an X-ray mirror |
|---|---|
| المؤلفون: | Aoyagi, M., Bose, R. G., Chun, S., Gau, E., Hu, K., Ishiwata, K., Iyer, N. K., Kislat, F., Kiss, M., Klepper, K., Krawczynski, H., Lisalda, L., Maeda, Y., Malmborg, F. af, Matsumoto, H., Miyamoto, A., Miyazawa, T., Pearce, M., Rauch, B. F., Cavero, N. Rodriguez, Spooner, S., Takahashi, H., Uchida, Y., West, A. T., Wimalasena, K., Yoshimoto, M. |
| المصدر: | Astropart. Phys. 158 (2024) 102944 |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena |
| الوصف: | XL-Calibur is a balloon-borne Compton polarimeter for X-rays in the $\sim$15-80 keV range. Using an X-ray mirror with a 12 m focal length for collecting photons onto a beryllium scattering rod surrounded by CZT detectors, a minimum-detectable polarization as low as $\sim$3% is expected during a 24-hour on-target observation of a 1 Crab source at 45$^{\circ}$ elevation. Systematic effects alter the reconstructed polarization as the mirror focal spot moves across the beryllium scatterer, due to pointing offsets, mechanical misalignment or deformation of the carbon-fiber truss supporting the mirror and the polarimeter. Unaddressed, this can give rise to a spurious polarization signal for an unpolarized flux, or a change in reconstructed polarization fraction and angle for a polarized flux. Using bench-marked Monte-Carlo simulations and an accurate mirror point-spread function characterized at synchrotron beam-lines, systematic effects are quantified, and mitigation strategies discussed. By recalculating the scattering site for a shifted beam, systematic errors can be reduced from several tens of percent to the few-percent level for any shift within the scattering element. The treatment of these systematic effects will be important for any polarimetric instrument where a focused X-ray beam is impinging on a scattering element surrounded by counting detectors. Comment: Submitted to Astroparticle Physics |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1016/j.astropartphys.2024.102944 |
| URL الوصول: | http://arxiv.org/abs/2402.15229 |
| رقم الأكسشن: | edsarx.2402.15229 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1016/j.astropartphys.2024.102944 |
|---|