Intracavity OptoGalvanic Spectroscopy not suitable for ambient level radiocarbon detection

Area of Science:

• Atomic, Molecular and Chemical Physics
• Environmental Science
• Analytical Chemistry

Background:

• IntraCavity OptoGalvanic Spectroscopy (ICOGS) emerged in 2008 as a potentially cheaper alternative to accelerator mass spectrometry for radiocarbon detection.
• The ICOGS technique was developed for applications in radiocarbon dating and atmospheric monitoring.
• A collaborative effort between Rutgers University and the University of Groningen established an ICOGS setup in 2012.

Purpose of the Study:

• To systematically evaluate the ICOGS setup at the University of Groningen for radiocarbon detection.
• To assess the technique's capability in differentiating CO2 samples with varying radiocarbon concentrations.
• To determine the suitability of ICOGS for ambient level radiocarbon measurements.

Main Methods:

• Experiments were conducted using CO2 samples with contemporary and highly depleted radiocarbon levels.
• In-house prepared CO2 samples with elevated radiocarbon levels were used due to initial differentiation failures.
• The Groningen ICOGS setup's performance was systematically evaluated.

Main Results:

• The Groningen ICOGS setup failed to differentiate between CO2 samples with radiocarbon concentrations differing by three orders of magnitude.
• Results from Groningen contrasted with findings from the Murnick group, aligning more with the Salehpour group's results.
• Even highly enriched CO2 samples yielded insignificant signals, indicating poor sensitivity.

Conclusions:

• The ICOGS technique, as implemented and tested at Groningen, is unsuitable for ambient level radiocarbon measurements.
• The method's inability to detect significant signals from enriched samples raises concerns about its overall efficacy.
• Further research or modifications may be needed to improve the sensitivity and reliability of ICOGS for radiocarbon detection.