Intracavity Optogalvanic Spectroscopy System for Radiocarbon Analysis*

Intracavity Optogalvanic Spectroscopy (ICOGS) is a laser-based technique for the measurement of Radiocarbon (C14). This method combines intracavity spectroscopy and the optogalvanic effect (OGE), where detection is via the impedance variation in a weak gas discharge. The amount of C14 present can be identified through vector decomposition of the measured components (Zero Air as buffer gas, Carbon 12 and Carbon 13 as off resonance absorbers, and Carbon 14 as on-resonance stimulated emitter). Recent improvements now integrate the buffer gas and off resonance absorbers to simplify the analysis and improve repeatability. Modifications to the algorithms reflect the experimental changes and improve on prior methods. We present the advantages/disadvantages of each method, thus expanding the versatility of the ICOGS technique. The objective is to develop a calibration curve to determine accurate quantification for samples of unknown C14 concentration. Radiocarbon analysis has many practical applications beyond dating, such as radioactive tracing in biological systems as well as for real-time determination of the concentration of C14 in the atmosphere.