AMS-validated high-precision radiocarbon analysis of 14C-enriched environmental samples by laser spectroscopy

: Radiocarbon (14C) is one of the key isotopes in the field of nuclear environmental protection. This difficult-to-measure isotope constitutes a substantial proportion of the nuclear industry's dose contribution, underscoring the imperative for precise measurement in regions loaded by 14C emissions. The currently used technologies such as accelerator mass spectrometry (AMS) and liquid scintillation counting (LSC) techniques are capable of determining the exact 14C content or ratio of 14C-enriched samples. However, the evolving, laser-based spectroscopic methods, such as Saturated-absorption CAvity Ring-down (SCAR) technology, may offer a fast, reliable, and cost-effective alternative for the analysis of lightly labeled carbonaceous materials or slightly 14C-enriched environmental and plant samples. The 14C-enriched plant samples examined in the study demonstrated that the SCAR method is capable of reproducing AMS measurement results with a difference of less than 4 % when measured from the same gas after δ13C correction. This study constitutes the inaugural demonstration and practical exemplification of subsamples formed from the same CO2 gas, after the combustion, being measured by AMS, SCAR, and Isotope Ratio Mass Spectrometry (IRMS) for 14C/12C and 13C/12C isotope ratios. The comparative study demonstrates that SCAR is capable of measuring the 14C/12C ratio of plant samples between 115 and 2600 pMC with sufficient accuracy and linearity, providing a new alternative for nuclear environmental protection and research in the case of organic samples exceeding the natural environmental level (∼100 pMC).