Detection of 59Ni at the Lund AMS facility

Abstract

In the use of small tandem accelerators for accelerator mass spectrometry (AMS), interfering isobars are often troublesome, especially when heavier isotopes such as 59Ni are to be measured. One way to reduce this problem is to combine AMS with the detection of characteristic projectile X-rays. After analysis in the AMS system, the ions are stopped in a suitable target and it is possible to identify the ions by atomic number and thereby separate the isobars. In order to lower the detection limit in the case of 59Ni in stainless steel samples, it is necessary to chemically reduce the content of 59Co in the sample. Further improvements in the reduction of the X-ray background and in the chemical reduction of cobalt have led to nearly a factor of 10 lower detection limit of 59Ni at the Lund AMS facility compared to what has been reported earlier. The content of 59Ni in some steel samples obtained from Swedish nuclear power plants has been measured and the results are presented here.