Development of ⁵⁹Ni/⁵⁸Ni measurements at CAMS

Full text: Nickel-59 is a long-lived radioisotope (t1/2=76,000a) with applications in nuclear security, dosimetry, and cosmochemistry. However, the measurement of ⁵⁹Ni via AMS is made difficult by the presence of isobaric ⁵⁹Co. Cobalt and Ni share very similar chemical behavior and are therefore difficult to fully separate using traditional sample purification chemistry. Furthermore, Co can be found in many components of the AMS ion source, target holders, and sample packing materials, in which Co cannot be removed via chemistry. Recent work at the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory (USA) has focused on developing a method of measuring ⁵⁹Ni/⁵⁸Ni on our 10MV FN tandem accelerator. In order to minimize the Co background, new ion source components have been made from materials low in Co. Additionally, a variety of materials have been investigated for target holders and sample packing. Results of these modifications will be presented along with measurement setup, charge state selection, and measurement challenges. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. We thank the U.S. Department of Energy's National Nuclear Security Administration, Office of Defense Nuclear Nonproliferation Research and Development, for financial support.