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

The AMS system at CNA has been the first 1MV 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 6×10−3mbar of argon (mass thickness of about 0.15μgcm−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.