Systems study for an advanced tritium detector

This thesis describes a thorough and comprehensive systems study on the development of an advanced tritium-in-air monitor. Three technologies were investigated for possible use in a state-of-the-art tritium detector system: double-resonance laser-induced fluorescence spectroscopy, direct beta detection using a CaF₂(Eu)/bismuth germanate phoswich structure, and indirect beta detection using a closed-loop liquid scintillation system.

The concept of each of these technologies is discussed in this thesis. Various detector systems are proposed, and the numerous components making up each system are selected based on performance and cost. Calculations of sensitivity and estimated purchase price are included in the analysis of each proposed system. Each is also evaluated in terms of its time constant, portability, movability, ability to distinguish between the elemental (HT) and oxide (HTO) forms of tritium in air, and the ability to reject false signals from external alpha-, beta-, and gamma-emitting radionuclides.

This thesis is intended to be used as an aid in the selection of a conceptual system to be developed as an advanced tritium-in— air monitor; therefore, development costs and probabilities of successful implementation are given for each proposed system. It is concluded that two systems, a laser-induced fluorescence detector and a CaF₂(Eu)/bismuth germanate detector, should be considered for further development, and a development scenario is recommended.