Statistical fluctuations in heavy charged particle tracks

Results of the following Monte Carlo track segment calculations for protons with energies of 1, 2, 5, and 10 MeV in liquid water were presented. (1) radial dose around a long segment of a proton track; (2) energy-loss straggling distributions for protons of different energies in 1 μm of water, (3) the distribution in the average absorbed dose around track segments of various lengths; (4) the relative standard deviations in these distributions as functions of the length of the track segments. Calculations such as those presented are useful for studying track phenomena on a microdosimetric scale, where statistical fluctuations are substantial. (author)