Precise measurement of Pb210 and Po210 contamination in bulk copper
e have established the new method to measure the Pb210/Po210 contamination in bulk copper using low background alpha counter. We measured the various kinds of copper and found that even oxygen free copper contaminates a few tens mBq/kg of Pb210. By electrolytic refining, most of Pb210 is removed. But small amount of Pb210 remain in the refined coppers. Also we found that Pb210 contamination of 6N copper is estimated to be equal or less than a few mBq/kg. This method to measure the bulk Pb210/Po210 contamination can apply to other materials.