Figure 1. . A schematic of the 200 keV ‘MICADAS’ accelerator mass spectrometry developed at ETH Zürich (footprint: 2.5 × 3 m).

Core concepts of ¹⁴C-accelerator mass spectrometry are summarized: negative ion production to eliminate the atomic isobar, low-energy mass filtering, high-energy collisions to eliminate molecular isobars, high-energy dipole mass spectrometry resolution of carbon isotopes to 1 amu, particle identification of ¹⁴C after electrostatic sector filtering. Ion beams of ¹²C and ¹³C are measured in off-axes Faraday cups.