Dosimetric Characterisation Of A Sub-Natural Background Radiation Environment For Radiobiology Investigations

Living systems have evolved in the presence of naturally occurring ionising radiation. REPAIR is a research project investigating the biological effects of sub-natural background radiation exposure in SNOLAB, a deep-underground laboratory. Biological systems are being cultured within a sub-background environment as well as two control locations (underground and surface). A comprehensive dosimetric analysis was performed. GEANT4 simulation was used to characterise the contribution from gamma, muons and neutrons. Additionally, dose rates from radon, K-40 and C-14 were calculated based on measured activity concentrations. The total absorbed dose rate in the sub-background environment was 27 times lower than the surface control, at 2.48 +/- 0.20 nGy hr(-1), including a >400-fold reduction in the high linear energy transfer components. This modelling quantitatively confirms that the environment within SNOLAB provides a substantially reduced background radiation dose rate, thereby setting the stage for future sub-background biological studies using a variety of model organisms.