Determination of the beta- branching ratio of 64Cu by mass spectrometric investigations of the decay products in neutron transmuted copper.

The beta- branching ratio of 64Cu was determined by investigating the resulting decay products in copper doped by neutron transmutation. The numbers of 64Zn and 64Ni atoms were analyzed using isotope dilution analysis combined with thermal ionization mass spectrometry. A beta- branching ratio of (38.06+/-0.30)% was obtained, which agrees with the study of Kawada (Appl. Radiat. Isot. 37 (1) (1986) 7) to a higher accuracy. However, our result differs from the value cited in the NUDAT database of (39.0+/-0.3)%.

Characterization of neutron transmuted zinc traces in pure copper materials by isotope dilution mass spectrometry.

The neutron transmutation doping (NTD) of highly pure copper with zinc was investigated as a promising means of achieving controlled gradation of the zinc content in the range 1-20 microg g(-1). The doping process leads to the enrichment of two stable isotopes 64Zn and 66Zn in a ratio which differs from that of natural isotopic distribution. Mass spectrometric investigations by thermal ionization mass spectrometry (TIMS) were performed to validate the results obtained by gamma spectrometry. The investigations included both determination of the isotopic ratios of the doped zinc isotopes and the analysis of the accumulated zinc contents by isotope dilution (ID) analysis. Thereby a sample-specific correction of the blank could be performed because the isotope 68Zn was not influenced, because of the transmutation process. The results obtained by TIMS prove the strict proportionality of the doped zinc content, in the range 5 to 20 microg g(-1), to the neutron fluence. Comparison with gamma spectrometric results showed a very good agreement within the uncertainties.