Computer-aided stochastic modeling of the radiolysis of liquid water.

A computer-aided stochastic model of the radiolysis of liquid water has been developed. It is based on Monte Carlo simulation of charged-particle tracks, a random-flight method to simulate diffusion of species and the Debye-Smoluchowski theory of reactions between radicals. The model takes into account the formation of ionizations, excitations and subexcitation electrons at the physical stage.

A precise ionization method for determination of the energy deposited in small sites of irradiated objects.

The ionization method for determination of the energy deposited in sensitive sites of irradiated objects is usually used with the assumption that deposited energy is directly proportional to the number of ionizations in a site. This assumption fails in two cases important for nanometer-sized sites: (1) when the fluctuation characteristics of deposited energy such as higher moments, probability distributions, etc. are determined instead of the mean value; (2) when the radiation field in a site is spatially non-uniform.

"Trion" code for radiation action calculations and its application in microdosimetry and radiobiology.

A code for calculations of electron, ion and photon radiation action on tissue-equivalent matter (water vapor) by the Monte Carlo technique is presented. The new "fluctuation detector" method is efficient in evaluating of probability distributions and moments of absorbed energy and number of ionizations in small sites. Spatial and energy distributions of particles fluences and fluctuation characteristics of radiation action on spherical and thread-like sites of nanometer diameter are compared with various experimental and theoretical data and discussed.

Theoretical estimation of quality factor for tritium.

A theoretical calculation of the tritium quality factor is made and some of the results are presented. These results may contribute to a better dose equivalent assessment of tritium since there is some uncertainty, as is reflected in published data that are inconsistent. The results in this study support the ICRU Report 40 recommended value.