[en] Focused ion beam implantation of 30-keV Ga⁺ ions in nanocrystalline diamond films was investigated by secondary-ion mass spectrometry (SIMS), using Cs⁺ primary ions for sputtering. Nine different implantation fluences ranging from 1 x 10¹³ to 1 x 10¹⁷ Ga⁺-ions/cm² were used, with implanted areas of 40 x 40 μm². The Ga concentration distributions of these implants were determined by SIMS depth profiling. Such 30-keV Ga implants were also simulated by a dynamic Monte-Carlo code that takes into account the gradual change of the near-surface composition due to the Ga incorporation. In both approaches, an essentially linear increase of the Ga peak concentrations with fluence is found up to ∼1 x 10¹⁶ cm^-2; for higher fluences, the Ga content approaches a saturation level which is reached at about 2 x 10¹⁷ cm^-2. The measured and simulated peak concentrations of the Ga distributions are in good agreement. The most probable range obtained from the experiments corresponds closely with the respective value from the simulations; the peak width determined by SIMS is somewhat broader, possibly caused by the roughness of the films