Effectiveness Study of Calibration and Correction Algorithms on the Prototype of the POLAR-2/LPD Detector

TL;DR

This study evaluates calibration algorithms for a gaseous X-ray polarimeter prototype, demonstrating significant reduction in residual modulation and improved polarization measurement accuracy, surpassing existing instruments at certain energies.

Contribution

Introduces a novel calibration algorithm combining parameterization, Monte Carlo simulation, and Bayesian iteration for gas X-ray polarimeters, enhancing measurement precision.

Findings

Residual modulation reduced below 1% after correction.

Linear relationship between polarization and modulation degrees.

Improved modulation degree by 2-15%, outperforming IXPE above 5 keV.

Abstract

Gaseous X-ray polarimetry refers to a class of detectors used for measuring the polarization of soft X-rays. The systematic effects of such detectors introduce residual modulation, leading to systematic biases in the polarization detection results of the source. This paper discusses the systematic effects and their calibration and correction using the Gas Microchannel Plate-Pixel Detector (GMPD) prototype for POLAR-2/Low-Energy X-ray Polarization Detector (LPD). Additionally, we propose an algorithm that combines parameterization with Monte Carlo simulation and Bayesian iteration to eliminate residual modulation. The residual modulation after data correction at different energy points has been reduced to below 1%, and a good linear relationship is observed between the polarization degree and modulation degree. The improvement in modulation degree after correction ranges from 2% to 15%, and the results exceed those of the Imaging X-Ray Polarimetry Explorer (IXPE) above 5 keV.