Inactivation of Cells by Heavy Ion Bombardment

This is the authors' abstract. We don't add key points for this paper.

The tracks formed in nuclear emulsion by energetic heavy ions are made up of grains sensitized by the passage of a single ion. Cells may also be inactivated by the passage of a single ion, in a mode called ion-kill. Emulsion tracks pass from the grain-count regime, where the tracks is a sequence of isolated grains, to the track-width regime, where the track is fully closed and has a cross-sectional area larger than that of an emulsion grain, with increasing values of z²/β ² for the charged particle causing the track. The measured value of the inactivation cross section for human kidney cells increases in a similar way. The response of cells is not the same as emulsion grains, because cells may also be inactivated by a gamma-kill mode, involving the cumulative effect of overlapping delta rays from several ions, in addition to the ion-kill mode present in both emulsion and cells. These considerations lead to the equations $P=σ /σ ₀=[1-e^{-z²/κ ...