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

⁹³Zr (t_1/2 = 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.