A Study of Background Conditions for Sphinx--The Satellite-Borne Gamma-Ray Burst Polarimeter

Abstract

SPHiNX is a proposed satellite-borne gamma-ray burst polarimeter operating in the energy range 50-500 keV. The mission aims to probe the fundamental mechanism responsible for gamma-ray burst prompt emission through polarisation measurements. Optimising the signal-to-background ratio for SPHiNX is an important task during the design phase. The Geant4 Monte Carlo toolkit is used in this work. From the simulation, the total background outside the South Atlantic Anomaly (SAA) is about 323 counts/s, which is dominated by the cosmic X-ray background and albedo gamma rays, which contribute ~60% and ~35% of the total background, respectively. The background from albedo neutrons and primary and secondary cosmic rays is negligible. The delayed background induced by the SAA-trapped protons is about 190 counts/s when SPHiNX operates in orbit for one year. The resulting total background level of ~513 counts/s allows the polarisation of ~50 GRBs with minimum detectable polarisation less than 30% to be determined during the two-year mission lifetime.

9 pages, 6 figures

References in corpus (3)

• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• Design and construction of the POLAR detector
• Science prospects for SPHiNX - a small satellite GRB polarimetry mission

Cited by in corpus (6)

• Estimate of the Background and Sensitivity of theFollow-up X-ray Telescope onboard Einstein Probe
• Comparison of simulated backgrounds with in-orbit observations for HE, ME and LE onboard Insight-HXMT
• Instrumentation and Future Missions in the Upcoming Era of X-Ray Polarimetry
• Measuring the Cosmic X-ray Background accurately
• In-orbit background simulation of a type-B CATCH satellite
• Gamma-ray burst localisation strategies for the SPHiNX hard X-ray polarimeter