In the event of an accidental or malicious dispersion of ¹⁴C-laden material into the environment, the rapid analysis of a large number of ¹⁴C samples, at levels between 1 and 10⁴ times modern would be required.  As a part of the Canadian CRTI program[1], IsoTrace has undertaken to develop a system to provide this capability, incorporating the automated combustion of samples and the production of the carbon ion beam directly from the resulting CO₂. While funded for environmental purposes, this system is expected to be useful for biomedical measurements and, with alternate transfer lines, for ¹⁴C measurements in the range of 20 to 100 pMC. 

Components of the system include the High Voltage Engineering model SO-110 hybrid gas / solid ion source, an Elementar Vario ELIII CNS analyser and locally built gas transfer line. The SO-110 source has been installed at the -45º position of the rotatable electric analyser of the IsoTrace AMS injection line. Ion optical work to optimise the transmission of the beam from this source through the injection line is in progress.  Tests of the elemental analyser, located adjacent to the ion source, have led to several improvements in the design and capacity of the in-line water traps.

The gas transfer line has two functions: (1) to scale the discharge rate of CO₂ from the elemental analyser to the input rate required by the ion source and (2) to permit switching of the gas stream so that the ion source can be injecting carbon ions from one sample while the elemental analyser combusts the following one. Unlike many elemental analysers, the Vario EL III is equipped with a trap specifically for CO₂. During the release from this trap, the CO₂ / helium mixture is injected into a sample loop. Standard gas chromatography valves are used to switch this loop from an initial helium purge stage, to accept the release from the elemental analyser and then to inject a further diluted CO₂ / helium mixture into the ion source. 

This paper will provide details of the design of this system and outline the progress to date in its implementation.

1. Chemical, biological, radiological and nuclear Research and Technology Initiative (an inter-departmental program of the government of Canada)