[en] The G-values of the acridine C-radical in poly(vinyl alcohol) film produced by the irradiation with several hundred MeV heavy ions decreased with increasing linear energy transfer (LET) value for the same ion. The radical yield was dependent on the fluence of the ions and was analyzed using the 'chemical' track model. The estimated radius of the chemical track decreases with increasing incident velocity of the same ion. At the same incident velocity, the radius increases with increasing atomic number of the ion