TOR
TOR
The Trondheim Oxidation and Reduction system, TOR, is the main instrument used to prepare graphite for 14C measurements in Trondheim. It can automatically run the combustion and reduction process of up to 10 samples in parallel in about 7 hours and can be used twice a day.
The combustion of solid organic samples is done in an elemental analyser (EA, type: Elementar microcube) which also measures the carbon and nitrogen contents of the samples. The resulting gas flow, a mixture of helium and combustion gasses, is directed towards one of the reduction reactors where a liquid nitrogen trap captures the CO2.
The system determines the sample size by measuring the pressure of the captured CO2 after re-evaporation. Then, hydrogen is added to match the sample size with a 10‑20 % excess. The oven then heats the Fe catalyst to about 550 °C while a Peltier cooler at about -30 °C freezes out water created in the graphitization reaction.