Modelling the Performance of Tritium Process Monitors from First Principles

Ionization chamber-based, in-line tritium process monitors play an important part in determining the behavior of a tritium system. The one-liter detection volume monitor has been characterized well through experiment and to respond linearly to tritium concentrations for the range of $1 {\mu}Ci/m^3$ to $1 Ci/m^3$. Additionally, it has been shown to behave nonlinearly for low voltage on the central anode and low pressure of the carrier gas. A computational model was developed from first principles that successfully describes the behavior of the one-liter monitor for each of these regimes. Predictions from the model are compared to previously-collected experimental data in order to determine validity and tune the model. The model will be expanded to incorporate additional detector geometries and designs in the future.