Models of performances of dosimetric telescopes in the anisotropic radiation field in low earth orbit

In the case of the International Space Station (ISS), the attitude of which is usually stabilized in the local vertical reference frame (airplane-like attitude), the anisotropies in the radiation field, such as the effect of the Earth's shadow, the angular dependence of the geomagnetic transmission factors and the East-West asymmetry in the South Atlantic Anomaly (SAA), cannot be ignored. One-dimensional telescopes used for dosimetry have strong directional sensitivity and therefore they might either under- or overestimate the dose equivalent. The application of 3D telescopes with three, mutually orthogonal axes improves significantly the measuring precision of the instrument. The present paper addresses the expected responses of 1D and 3D telescopes for anisotropic radiation in low Earth orbit on board the ISS. Calculations were performed to estimate the differences between the obtained LET-spectra of the untrapped particles as well as the absorbed dose values. The directionality of trapped protons in the SAA was addressed as well.