CUbesat Solar Polarimeter (CUSP) Sensitivity Estimation and Performance Optimization using Geant4

TL;DR

This paper presents the development and initial simulation results of a Geant4-based model to estimate the sensitivity and optimize the performance of the CUSP solar polarimeter for measuring solar flare polarization in the X-ray band.

Contribution

It introduces a detailed Geant4 simulation framework for CUSP, enabling accurate sensitivity estimation and performance optimization of the CubeSat polarimeter.

Findings

Geant4 simulation accurately models detector response.

Backscattering shielding impacts sensitivity and was optimized.

Initial sensitivity estimates inform instrument design improvements.

Abstract

The CUbesat Solar Polarimeter (CUSP) aims to measure the linear polarization of solar flares in the 25-100 keV X-ray band using a Compton scattering polarimeter. CUSP will allow us to study the magnetic reconnection and particle acceleration in the flaring magnetic structures of our star by providing high-sensitivity polarization measurements. CUSP is a project in the framework of the Alcor Program of the Italian Space Agency aimed to develop innovative CubeSat technologies and missions. As part of CUSPs Phase B study, which began in December 2024 and will continue for one year, we present the development status of the Geant4 based simulator to accurately simulate the detectors response and initial results on the sensitivity of the instrument. Geant4 Monte Carlo simulation is used to assess the physical interactions of the source photons with the detector and the passive materials. We implemented a detailed CUSP Mass Model within Geant4 to simulate and estimate the instruments sensitivity, correcting the geometric effects of the instrument. We also evaluated the effect of backscattering shielding on the sensitivity to optimize the mass model of the instrument.