In the relentless pursuit of harnessing fusion energy, scientists are continually pushing the boundaries of technology to monitor and control the intense conditions within fusion reactors. A recent study published in Results in Optics, led by Luca Weninger from the Laboratoire Hubert Curien at Université Jean Monnet in Saint-Etienne, France, has introduced a groundbreaking method for monitoring 14 MeV neutron beams using radioluminescent silica-based optical fibers. This innovation could revolutionize how we approach beam monitoring in fusion experiments, offering a robust solution to the harsh environments of fusion-related facilities.
The research focuses on the use of Ce-doped optical fibers, which exploit the radiation-induced luminescence (RIL) phenomenon. These fibers, when exposed to high-energy neutrons, emit light that can be measured to determine the neutron flux. This method leverages the inherent advantages of optical fibers, such as their small size, lightweight, and immunity to electromagnetic interference. “The key advantage of our setup is its simplicity and remote operability,” Weninger explains. “By using a single-ended configuration, we can avoid exposing the detectors to direct radiation, which is a significant challenge in fusion environments.”
The study involved testing two 2-cm long Ce-optical fibers—one pristine and one pre-irradiated with X-rays at 250 kGy(SiO2)—at the Frascati Neutron Generator (FNG) of ENEA in Italy. The fibers were subjected to a neutron flux ranging from 4 × 107 to 4.5 × 108 n cm−2 s−1. The results were striking: the pre-irradiated fiber showed a clear improvement in RIL response, with a maximum deviation in fluence measurements of just 4%, compared to 6% for the pristine fiber. Both values are lower than the 7% deviation between the facility’s alpha counter and fission chamber, highlighting the potential accuracy of this new monitoring method.
The implications for the energy sector are profound. Fusion energy, often touted as the holy grail of clean and abundant power, requires precise control and monitoring of plasma conditions. The ability to accurately measure neutron fluxes in real-time could enhance the safety and efficiency of fusion reactors, bringing us one step closer to practical fusion power. “This technology could be a game-changer for fusion experiments,” Weninger notes. “It provides a reliable and remote monitoring solution that can withstand the extreme conditions of fusion environments.”
As the world continues to seek sustainable energy solutions, innovations like this one are crucial. The development of radioluminescent silica-based optical fibers for neutron beam monitoring not only advances our understanding of fusion dynamics but also paves the way for more efficient and safer fusion reactors. With further refinement, this technology could become a standard tool in fusion research, driving us closer to a future powered by clean, limitless energy. The study, published in Results in Optics, or ‘Optical Results’ in English, underscores the ongoing efforts to harness the power of fusion and the critical role that advanced monitoring technologies will play in this endeavor.
