Technologies for obtaining radio-pure materials : methods of low radioactivity detection

This paper discusses selected problems arising from the presence of radioactive background sources in experiments searching for extremely rare processes. Physical properties of ^{42}K ions, present in argon as a progeny of ^{42}Ar, were investigated. A model of ^{42}K ions behavior in liquiefied argon is presented. Also, construction and operation of an electrostatic ^{222}Rn monitor of gaseous nitrogen is outlined