Purification of 210Po Groundwater for Astrophysics and Environmental Applications

Abstract

The detection of solar neutrinos at Borexino requires ultra clean scintillator conditions and minimal background radiation from naturally occurring isotopes like 210Po. Other elemental isotopes have been successfully reduced below threshold values by scintillator purification methods like gas stripping, filtration, and water extraction but 210Po has been highly resistant. An attempt has been made to purify the water used for water extraction even further, through methods like reverse osmosis, ion exchange, and continuous deionization, which produce significant, but not complete, 210Po purification. Unfortunately, not enough is known about the forms Polonium takes in groundwater solutions to fully understand why these methods do not purify water completely. This thesis uses distillation as a method to better understand the forms Polonium may take in water. In addition to the applications to neutrino detection, the understanding of the forms 210Po takes in groundwater systems has significant importance to cleaning the environment of anthropogenic sources. 210Po is increasingly deposited in the soil and groundwater from industrial sources, and can have latent effects down the line for producers like plants and bacteria as well as secondary consumers like animals and humans. Being able to describe the compounds and properties of 210Po in the environment is a huge advantage for eventually ridding the environment of this poisonous isotope.