129I measurements on the 1 MV AMS facility at the Centro Nacional de Aceleradores (CNA, Spain)

The AMS system at CNA has been the first 1 MV compact AMS system designed and manufactured by HVE. In this paper we present the experimental set-up for 129I measurements in this facility. Charge state +3 has been selected at high-energy side and an optimum stripper pressure of 6×10−3 mbar of argon (mass thickness of about 0.15 μg cm−2) has been reached to obtain lowest blank values (129I/127I≅3×10−13). The measurements of the reference materials provided by the IAEA have demonstrated the viability of this facility to make routine measurements of 129I at environmental levels. This blank value obtained is enough for the measurement of most environmental samples and comparable with other reported backgrounds obtained in facilities working at higher energies and higher charge states.

► At the CNA the 1 MV AMS system has been set-up for the measurement of 129I in charge states 3+ and 4+. ► The sensitivity is about 10−13, enough for the measurement of most environmental samples. ► Measurement of standards demonstrated that the ratios agree perfectly with the nominal values. ► The technique was validated with the measurement of 129I content in four reference materials.