  The Atmospheric Radiation Interaction Simulator (AtRIS) was used to model the
altitude-dependent Venusian absorbed dose and the Venusian dose equivalent. For
the first time, we modeled the dose rates for different shape-, size-, and
composition-mimicking detectors (phantoms): a CO$_2$-based phantom, a
water-based microbial cell, and a phantom mimicking human tissue. Based on a
new model approach, we give a reliable estimate of the altitude-dependent
Venusian radiation dose in water-based microorganisms here for the first time.
These microorganisms are representative of known terrestrial life. We also
present a detailed analysis of the influence of the strongest ground-level
enhancements measured at the Earth's surface, and of the impact of two historic
extreme solar events on the Venusian radiation dose. Our study shows that
because a phantom based on Venusian air was used, and because furthermore, the
quality factors of different radiation types were not taken into account,
previous model efforts have underestimated the radiation hazard for any
putative Venusian cloud-based life by up to a factor of five. However, because
we furthermore show that even the strongest events would not have had a
hazardous effect on putative microorganisms within the potentially habitable
zone (51 km - 62 km), these differences may play only a minor role.
