Cellular and dosimetric characterization for biological studies of sub-natural background radiation

Abstract

Living things have evolved and grown in the presence of natural background radiation. Many biologic studies have been conducted with levels above natural background, but very few have examined sub background levels of radiation. A specialized tissue culture incubator (STCI) was constructed to shield against environmental radiation within SNOLAB. GEANT4 simulations of the STCI results showed a substantial decrease in dose rate compared to above ground and below ground incubator environments at 0.51 nGy/hr (for the STCI) vs 18.51 nGy/hr and 19.1 nGy/hr respectively, which equates to a 37.5 fold and 36.3 fold reduction in dose respectively. Compared to other sub background experimental dose rates (such as those conducted by Gran Sasso), the STCI is lower by a factor of 7.5. Neoplastic transformation assays were run above ground using the CGL1 hybridized cell line, both treated with aluminum and without. This experiment has laid out the protocol for future below ground assays in SNOLAB using the STCI. It has also led to interesting trends worth studying in future experimentation. Compared to the 0 mGy control, the 3000 mGy dose point was statistically significant (p-value <0.05) both with aluminum and without.