PIX: an instrument to measure atmospheric ionizing particles based on a single MiniPIX sensor

This paper presents the PIX instrument based on a raspberry Pi and a MiniPIX device dedicated to make measurements of ionizing particles onboard stratospheric balloons. The hardware part and the software part of the PIX instrument are described. All the characteristics of the instrument are given in this paper. The three flight opportunities are also presented, with the associated measurements. The methodology to calculate fluxes based on measurements is explained. In particular, the calculation of response functions of protons, electrons, and photons by using Monte-Carlo simulations, the identification algorithm based on a neural network trained with simulated data, and the calculation of fluxes from count rates are described. Some measurements performed in different facilities are presented. A part of these experimental tracks have been used to challenge the neural network previously trained with simulated date, to check the robustness of the algorithm. Proton, electron, and photon fluxes are presented and compared to the MAIRE model.