Elemental characterization of impurities at trace and ultra-trace levels inmetallurgical lead samples by INAA

摘要

The purity of several economically important metals is routinely verified by a reference material.Further,it isessential to provide a means of maintaining the consistency between laboratories and on disseminating theaccurate value.This work,developed within an activity of certification promoted by EURATOM,reports the results on impurity determination(Ag,As,Cd,Ni,Sb,Sn,Te and Zn)at trace(μg g1)and ultra-trace(ng g1)levels inthree metallurgical lead samples(99.99% of purity). Among the different analytical techniques available for the characterization,the use of a nuclear technique, i.e. Instrumental Nuclear Activation Analysis,hasallowed to reach high sensitivity and to obtain accurate values for these elements.The irradiations were performed in the rotating rack(Lazy Susan)and in the central channel of the TrigaMark II reactor reaching a total integrated flux of 9.36×1017 n cm2 and 2×1019 n cm2,respectively.The results about the determination of elements such as Ni,Sn,Te and Zn present at ultra-trace levels(ng/g),are showed and discussed.This task is very interesting for the radio-analytical and methodological implications:in fact,for analyzing them a radiochemical separation is involved and an anti-Compton gammaspectrometer is necessary due to their very low levels.