engleski

A comparison of calculated and measured W values in tissue-equivalent gas mixtures

We calculated the mean energy required to produce an ion pair (W) in methane-, propane-, and butane-based tissue-equivalent (TE) gas mixtures from W values in pure constituent gases according to various model for energy partition among gas components. We found an agreement between the experimental and calculated W values in the methane-based TE gas regardless of the model concept. In contrast, only those models which take into account differences in the stopping powers, total ionization cross sections and model constants of gas components give acceptable results for the propane-based TE gas. The calculated W value for high-energy electrons in isobutane-based TE gas mixture is 25.2 eV and for 5 MeV alpha-particles it is 28.0 eV.

W value ; TE gas mixtures

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