Removal of the long-lived ~(222)Rn daughters from copper and stainless steel surfaces

摘要

Removal of the long-lived ~(222)Rn daughters from copper and stainless steel surfaces was investigated. Etching and electropolishing were applied to discs exposed earlier to a strong radon source for ~(210)Pb, ~(210)Bi and ~(210)Po deposition. Cleaning efficiency for ~(210)Pb was tested with a n-type high purity germanium spectrometer, for ~(210)Bi a beta spectrometer and for ~(210)Po an alpha spectrometer was used. According to the performed measurements electropolishing removes very effectively all the isotopes from copper and stainless steel. Copper etching reduces efficiently lead and bismuth however for polonium the effect is negligible because of its fast re-deposition. For stainless steel, etching is much more effective compared to copper and it also works for ~(210)Po.