Climate Change to the Nuclear Fuel Cycle: Expanding the spectral ¹⁴CO₂ database for non-AMS Field Measurement Systems

Accelerator Mass Spectrometry (AMS) is well known and universally employed for radiocarbon analysis but is not adaptable to in-situ field measurements limiting applications. ¹⁴CO₂ is a key tracer for fossil fuel CO₂ as well as for release of enriched ¹⁴CO₂ characteristic of the nuclear fuel cycle with ∆¹⁴CO₂ values ranging from -1000 to ∼+500 per mil. However, to exploit the full value of in situ ¹⁴CO₂ data in diverse climate change and nuclear fuel cycle applications, high data rate temporal and spatial field measurement sensors and systems are required. The development of non-AMS methods based on quantum cascade laser, cavity ring down and optogalvanic spectroscopy are emerging applications but not fully developed for field use or widely accepted. Spectral data for lasing transitions for ¹⁴CO₂ are lacking in contrast to HITRAN data available for ¹²CO₂ (626) and ¹³CO₂ (636) (among other isotopologues 628, 638, etc.) in the spectral databases limiting development and innovation in non-AMS ¹⁴CO₂ sensors and systems. We review the corpus of ¹⁴CO₂ spectral data available in the literature and document grating tuned isotopic lasers (e.g., Freed 1990¹; Bradley et al., 1986²), well suited for expanded spectral studies of ¹⁴CO₂ and inclusion in the HITRAN database. Non-AMS ¹⁴CO₂ approaches are reviewed with suggestions for future work to support field systems for ¹⁴CO₂ measurements. Available isotopic lasers for ¹⁴CO₂ collaborative studies are described.