Instrumentation, control and monitoring of superheated liquid detectors for detection of nuclear materials at the Portuguese Research Reactor

Nuclear and radioactive materials see regular use in our daily lives. Whether associated with energy production, research or medical applications, there are more and more nuclear materials in circulation across the world, making their control and detection necessary to ensure the health and safety of the population. However, the loss of these materials is not as uncommon as one would expect.

Ranging from improper disposal to incidents related with other malicious uses, the reasons for the loss of these materials mostly range from the inability of current detectors to be able to detect shielded radiation sources.

This thesis investigates the usage of superheated liquid detectors as a way to detect shielded radiation sources. This was achieved through shielding different radiation sources with different attenuating materials commonly used in scenarios of smuggled radioactive materials.

The Superheated Detectors are coupled to an acoustic instrumentation system previously used by the SIMPLE project in search of dark matter as well to an optical instrumentation system capable of identifying nucleation events through a machine learning algorithm.

The inclusion of this optical system allowed to corroborate the data obtained from the acoustic system, being able to currently measure and detect observed events within the detector gel with a precision rate of 81.25%, thus improving the efficiency of these devices, allowing for the detection of shielded sources.