AMS is a highly sensitive method which enables detection of isotopes in minute quantities. Therefore, even trace amounts of foreign matter entering the specimen at the preparation stage greatly influence the results. The following steps are required for¹⁴C analysis; l) combustion of the samples (such as organic matters, carbonates) into carbon dioxide, 2) purification of the carbon dioxide gas, 3) graphitization, 4) packing of the graphite into the target holder. During the operation, the sample is in danger of being contaminated by carbon-dioxide, oil-mist, dust, etc. in the ambient environment.

To minimize specimen contamination and allow accurate and high precision measurements, our facility has two clean-rooms for preparing the samples. The clean-rooms are equipped with a glass vacuum line for purification of carbon-dioxide gas designed to prevent contamination by vacuum oil and / or grease, a clean-booth, water purifying device, an electronic balance and so on, to keep the sample contamination to minimum in all stages.

Graphate reaction vessel.         An electric farnace heated CO₂ and iron catalysis to produce graphite.

Graphite produced on iron powder.    Pressing graphite into cathode holder.

.The central hole of cathode holder has 1mm diameter.

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