| Name: | Kiran M Jayasurya |
| Affiliation: | U R Rao Satellite Centre |
| Conference ID : | ASI2024_639 |
| Title : | Multifaceted Simulations to design a TPC Polarimeter for Soft to Medium X-rays |
| Authors : | Kiran M Jayasurya1, Koushal Vadodariya1, Radhakrishna V1 |
| Authors Affiliation: | 1 Space Astronomy Group, U R Rao Satellite Centre, ISRO, Bengaluru-560037, India |
| Mode of Presentation: | Poster |
| Abstract Category : | Facilities, Technologies and Data science |
| Abstract : | X-ray polarimetry provides a unique tool to study emission mechanisms and, accretion and magnetic field geometry in astronomical sources. Photoelectric polarimeters exploit the fact that the photoelectron, ejected after photoelectric absorption, is preferentially emitted in the direction of orientation of the electric field of the incident photon. The photoelectron creates an ionization track/trail which gets randomized due to Coulombic interactions. In a Time Projection Chamber (TPC) based polarimeter, the readout is parallel to the photon direction and the electron track can be imaged in the plane perpendicular to it. The initial part of the track needs be identified and fit with an algorithm to reconstruct the initial photoelectron emission angle. The modulation curve generated from the distribution of the reconstructed angles therein gives information on the polarization properties of the incident photon beam. The modulation factor of the instrument is highly sensitive to the quality of the imaged tracks which in turn depends on the properties of the gas used and the static electric fields involved. Results from simulation tools like MagBoltz, Garfield++, ANSYS, with MATLAB, have been used to efficiently compute an overall outcome with which we define figure of merit for design convergence. The robustness and relative simplicity of the procedure allows one to derive TPC parameters for a desired energy in X-ray. |
