Experimental verification of off-axis polarimetry with Cadmium Zinc Telluride detectors of AstroSat-CZT Imager
| Autor: | C. S. Vaishnava, N. P. S. Mithun, Santosh V. Vadawale, Esakkiappan Aarthy, Arpit R. Patel, Hiteshkumar L. Adalja, Neeraj Kumar Tiwari, Tinkal Ladiya, Nilam Navale, Tanmoy Chattopadhyay, A. R. Rao, Varun Bhalerao, Dipankar Bhattacharya |
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| Rok vydání: | 2022 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Space and Planetary Science Control and Systems Engineering Mechanical Engineering FOS: Physical sciences Astronomy and Astrophysics Astrophysics - Instrumentation and Methods for Astrophysics Astrophysics - High Energy Astrophysical Phenomena Instrumentation Instrumentation and Methods for Astrophysics (astro-ph.IM) Electronic Optical and Magnetic Materials |
| DOI: | 10.48550/arxiv.2209.00222 |
| Popis: | The Cadmium Zinc Telluride Imager (CZTI) onboard AstroSat consists of an array of a large number of pixellated CZT detectors capable of measuring the polarization of incident hard X-rays. The polarization measurement capability of CZTI for on-axis sources was experimentally confirmed before the launch. CZTI has yielded tantalizing results on the X-ray polarization of the Crab nebula and pulsar in the energy range of 100 - 380 keV. CZTI has also contributed to the measurement of prompt emission polarization for several Gamma-Ray Bursts (GRBs). However, polarization measurements of off-axis sources like GRBs are challenging. It is vital to experimentally calibrate the CZTI sensitivity to off-axis sources to enhance the credence of the measurements. In this context, we report the verification of the off-axis polarimetric capability of pixellated CZT detectors through the controlled experiments carried out with a CZT detector similar to that used in CZTI and extensive Geant4 simulations of the experimental set-up. Our current results show that the CZT detectors can be used to measure the polarization of bright GRBs up to off-axis angles of ~60 degrees. However, at incidence angles between 45-60 degrees, there might be some systematic effects which needs to be taken into account while interpreting the measured polarisation fraction. Comment: Accepted for publication in JATIS |
| Databáze: | OpenAIRE |
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