Radon assay and purification techniques Available to Purchase

Radon is a source of background in many astroparticle physics experiments searching for rare low energy events. In this paper an overview about radon in the field is given including radon detection techniques, radon sources and material screening with respect to radon emanation. Finally, also the problem of long-lived radioactive $222Rn$-daughters and the question of gas purification from radon is addressed.