Zr/Nb isobar separation experiment for future 93Zr AMS measurement

93Zr (t1/2 = 1.6 Ma) is mostly produced by the main s-process in low-to-intermediate mass AGB stars. Large uncertainty exists in the current 92Zr(n,γ)93Zr Maxwellian Average cross section. This could have significant impact on nucleosynthesis calculations. Large amounts of 93Zr are also produced in nuclear reactors and pose long-term environmental radioactivity. Hence, measurement of 93Zr by the AMS is important for both fields above. We report here on progress in the development of AMS method to measure 93Zr. Compared with 98 MeV beam energy, Zr/Nb isobar position separation was improved using 155.2 MeV beam energy and Gas-Filled Magnet. Energy loss measurement with increased beam energy inside the detector indicates that higher beam energy can improve isobar energy loss separation. A chemical procedure to reduce the Nb content in Zr samples has been developed and tested. It reduces the 93Nb content by a factor of 1000.