Optimization of the final settings for the Space-borne Hard X-ray Compton Polarimeter POLAR

TL;DR

This paper details the optimization process for the final settings of the POLAR space-borne X-ray polarimeter, enhancing its ability to measure gamma-ray burst polarization in space.

Contribution

It introduces a systematic procedure for optimizing POLAR's high voltage and threshold settings based on ground calibration data.

Findings

Optimized high voltage and threshold settings for POLAR.

Verification of settings through ground calibration tests.

Enhanced detection capabilities for gamma-ray burst polarization.

Abstract

POLAR is a compact wide field space-borne detector dedicated for precise measurements of the linear polarization of hard X-rays emitted by transient sources in the energy range from 50 keV to 500 keV. It consists of 1600 plastic scintillator bars grouped in 25 detector modules that are used as gamma-ray detection material. Its energy range sensitivity is optimized for detection of the prompt emission photons from the gamma-ray bursts. Measurements of the GRB polarization provide unique information on emission mechanisms as well as on composition and structure of the GRB jets. The POLAR instrument was developed by international collaboration of Switzerland, China and Poland. It was launched in space on-board the China Space Laboratory TG-2 on September 15th, 2016. Based on the ground calibration data, several high voltage and threshold settings were calculated and verified in order to obtain various energy ranges and optimized signal to background conditions for different measurement purposes. In this paper we present optimization procedure details and current test results.