Status of low-energy AMS detection of Iodine-129 at the Centro Nacional de Aceleradores: performance and background correction
¹²⁹I is a long–lived radionuclide of environmental and nuclear relevance. At the CNA, its detection via Accelerator Mass Spectrometry (AMS) is routinely performed using the 1 MV SARA system. Recent upgrades—such as the introduction of helium as stripper gas and the selection of the 2+ charge state—h...
| Autores: | , |
|---|---|
| Formato: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2026 |
| País: | España |
| Recursos: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:dnet:idus________::c7b128e24edada5a8dcdf58cd7c24166 |
| Acesso em linha: | https://hdl.handle.net/11441/186491 https://doi.org/10.1016/j.nimb.2026.166174 |
| Access Level: | acceso abierto |
| Palavra-chave: | Accelerator Mass Spectrometry (AMS) Iodine-129 |
| Resumo: | ¹²⁹I is a long–lived radionuclide of environmental and nuclear relevance. At the CNA, its detection via Accelerator Mass Spectrometry (AMS) is routinely performed using the 1 MV SARA system. Recent upgrades—such as the introduction of helium as stripper gas and the selection of the 2+ charge state—have increased the transmission efficiency to more than 40% at 0.7 MV. This work presents a comprehensive analysis of background sources affecting ¹²⁹I²+ detection, including molecular interferences, high-energy tails of ¹²⁷I, and ion source cross-contamination. We introduce a two-step correction protocol: (1) subtraction of a fixed ¹²⁹I count rate to account for persistent contamination, and (2) subtraction of the average corrected blank ratio. This method effectively removes current-dependent effects, particularly in low-level samples. We analysed the influence of mixing AgI with Nb and observed only a minor impact on background levels. The optimal AgI:Nb mixing ratio was found to be between 1:1 and 1:2. Validation with real samples confirms improved accuracy and reliability in ultra–trace ¹²⁹I analysis. These findings strengthen the capabilities of the SARA facility for applications in oceanography, radioecology, and nuclear forensics. |
|---|