The 14C3^ are then directed into a Faraday cup and counted. Under vacuum, the graphite is bombanâed by a beam of Cs+ and, among other particles, C~ is sputtered off and accelerated down the first half of the tandem accelerator, the beam of C*~ strikes a carbon foil and is converted to C^ and other species, which are then accelerated down the second half of the accelerator into a series of magnets and velocity filters which completely separate the C-3+ from other particles.
Carbon from the object to be dated is introduced into the system in the form of graphite on a tantalum strip at the ion source. The need to be able to distinguish between large amounts of -^N and much smaller amounts of l^C renders the use of expensive high energy physics equipment necessary.Ī general plan of the equipment is given in figure 1. The accelerator method for C dating is based on the principle of the mass spectrometer and counts individual atoms, rather than £ emission from nuclear decay, as is the case in conventional radiocarbon dating.
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