Researchers at the University of Maine are developing wireless, battery-free sensors designed to operate within the extreme environment of a fusion reactor, a project supported by a recent $500,000 grant from the U.S. Department of Energy. The team, led by professor of electrical and computer engineering Mauricio Pereira da Cunha, is collaborating with the Princeton Plasma Physics Laboratory to create a new class of diagnostics capable of providing real-time data on temperature, pressure, and gas composition from inside the vacuum vessel. Current monitoring techniques are often limited to external measurements, providing an incomplete picture of the plasma-facing component conditions critical for optimizing reactor performance and ensuring operational safety. Source: The University of Maine

The sensor technology is based on surface acoustic wave (SAW) devices fabricated from langasite crystals, a piezoelectric material known for its stability at high temperatures. The sensors function passively; an external antenna transmits a radio frequency signal to the device, which then reflects a modified signal back. The characteristics of this reflected wave contain precise information about the physical conditions at the sensor's location. This wireless, battery-free architecture is essential for deployment in an environment characterized by intense radiation, strong magnetic fields, and temperatures projected to reach up to 1,000°C (1,800°F). The project aims to overcome the material and operational challenges that have historically precluded the use of embedded electronics in such harsh settings. Source: The University of Maine

The sensor technology is based on surface acoustic wave (SAW) devices fabricated from langasite crystals, a piezoelectric material known for its stability at high temperatures.

This diagnostic development addresses a critical need across various fusion confinement concepts. For tokamaks and stellarators, real-time monitoring of first-wall temperature and neutral gas pressure can inform divertor heat load management and impurity control strategies. The ability to place robust sensors directly on plasma-facing components would provide unprecedented data for validating plasma edge models and developing more effective operational scenarios. According to Andrei Zvyagin, a PPPL engineer collaborating on the project, such data is vital for understanding and mitigating plasma-material interactions, a key challenge for achieving long-pulse, high-performance operations in future fusion power plants. Source: The University of Maine

The research team will focus on fabricating and testing the langasite sensors to confirm their resilience and measurement accuracy under simulated fusion reactor conditions. Key performance indicators will include signal integrity in the presence of strong magnetic fields and survivability under high thermal and radiation loads. Successful validation could pave the way for integration into experimental devices, offering a new stream of empirical data to refine both machine operation and the design of next-generation reactors. Beyond fusion, the sensor technology has potential applications in other high-temperature, high-radiation environments, including advanced nuclear fission reactors and industrial combustion systems. Source: The University of Maine