Development of isobar separation for 182Hf AMS measurements of astrophysical interest

The detection of 182Hf by Accelerator Mass Spectrometry (AMS) is greatly complicated because of the stable and common isobar 182W. Although significant W reduction can be achieved during negative ion formation using HfF5-, additional separation is necessary to achieve detection sensitivities sufficient for astrophysical applications, i.e. detection of potential supernova-produced 182Hf on Earth. In this paper, we present a new development of isobar separation using the ΔTOF detection method at the Munich MP Tandem accelerator (TV = 14 MV), where ion energies for 182Hf of about 1 MeV/amu can be achieved. Particular attention is drawn on specific energy loss and energy loss straggling measurements in various materials, the basis for our method of isobar separation.