Energy distribution around 175 MeV Ar ion path in argon at the density of water

The ionization distribution in Ar gas by 175 MeV Ar ion was measured, and r educed to the energy density as a function of the radial distance in water. The energy density within the radial distance smaller than 294 nm decrease d proportionally to the inverse of the square of the distance, Beyond this distance, however, the energy density decreased more steeply. The deposited energy except in the core region of the track amounts to 89% of linear ene rgy transfer (LET). (C) 1999 Elsevier Science Ltd. All rights reserved.