Figure 1.

GCR-induced energy deposition rate below the surface of Mars based on the GEANT4 numerical model. The peak energy deposition rate is ~ 2 × 10⁷ eVg⁻¹ s⁻¹, which falls down to ~ 3 × 10⁵ eVg⁻¹ s⁻¹ at 2 m depth. It can be seen that a dose rate of 10⁶ eVg⁻¹ s⁻¹ exists between 1–2 m depth on Mars, which is the measured dose rate in deep subsurface ecosystems on Earth¹⁴.