Diamond-based Tritium Detectors

Tritium (the radioactive heavy isotope of hydrogen) is used as the fuel in nuclear fusion reactors. However it is rare, expensive and difficult to produce. Moreover, being radioactive (a beta-emitter), it is dangerous if it escapes from containers into the air, and this is even more problematic because tritium is notoriously difficult to detect reliably. Therefore, there is a pressing need for a technology that can detect tritium reliably and reproducibly over long periods of time.

One possibility is to use a diamond-based voltaic sensor, which comprises a thin-film vertical-diode structure that is configured to be sensitive to the decays of low-energy beta-emitting radioisotopes impinging on the sensor surface. Diamond is 'radiation-hard', which means it can be exposed to a very large dose of radiation before becoming significantly damaged. Thus, a diamond-based tritium detector should have a very long lifetime.

This research seeks to develop and to demonstrate a highly novel diamond-based tritium-detector technology that can be deployed in the fusion fuel-delivery system, as well as the fusion-reactor walls to monitor tritium use and migration in real time.

This research is funded by the UKAEA’s Fusion Industry Programme, project title STRIDES - Studying Tritium in Diamond Energy Structures. The project has so far demonstrated a single-crystal diamond sensor responding to simulated tritium beta-decays using an in-house designed COTS detector electronics module.