Correlated ionisations in two spatially separated nanometric volumes within the track structure of 241Am alpha particles: comparison with Monte Carlo simulations. (November 2022) - Hilgers, Gerhard
Abstract: The production of two double strand breaks in spatially separated locations on the DNA molecule can cause the loss of a whole DNA loop. This loss, which can be of substantial length depending on the geometrical position of the two damaged sites, depends on the degree of correlation between ionisation clusters formed in sites of several nanometres in size. The first part of this paper reported on nanodosimetric measurements of alpha particle tracks in 1.2 mbar H2 O, 1.2 mbar C3 H8 and 1.2 mbar C4 H8 O with the PTB ion counter nanodosimeter. In this second part, the focus is on the geometrical characterisation of the two sites simulated with the nanodosimeter in the three target gases and on the comparison of the measurement results with Monte Carlo simulations. The measurements in 1.2 mbar C3 H8 were simulated with PTra, a track structure code dedicated to modelling the PTB ion counter nanodosimeter. Further simulations were performed with Geant4-DNA for 241 Am alpha particle tracks in liquid water. Simulations of the experiment were found to be in good agreement with the measurements for the investigated irradiation geometries. Highlights: Measurement and simulation of correlated ICSDs of two sites in terms of liquid H2 O. Determination of geometry parameters of two nanometric target sites in liquid H2 O. Degree of correlation depends on irradiation geometry.