Reduced dimensionality, elevated tolerance? A perspective on 2D materials for fusion diagnostics

Whether in the distant reaches of outer space or deep within magnetic confinement fusion reactors, our exploration of high-energy particle radiation environments continues to evolve-driving an urgent need for diagnostic technologies capable of withstanding extreme radiation exposure. As these technological frontiers expand, materials are increasingly subjected to radiation intensities far beyond those encountered in previous decades, pushing conventional systems to their operational limits. This challenge is especially acute in the pursuit of practical fusion energy, where the development of resilient magnetic sensor technologies capable of sustained, reliable operation under intense neutron flux is essential. In this Perspective, we examine this challenge through the lens of condensed matter physics, proposing that reducing the dimensionality of sensing materials-from bulk to two-dimensional (2D) systems-offers a promising route to mitigate radiation-induced degradation. Lower dimensionality suppresses the formation of collision cascades, which are responsible for rapid defect accumulation in bulk materials, thereby offering a pathway toward radiation-tolerant sensor platforms. We focus on recent advances in graphene-based Hall sensors deployed in fast-neutron-radiation environments, where fluence levels up to 2 ×1018 n cm^-2have been sustained with negligible structural damage, corresponding to a relative defect concentration below 0.01%. These findings underscore graphene's potential as a candidate for neutron-radiation-resistant electronics. However, key open questions remain-most notably, the ultimate neutron fluence tolerance of graphene-based systems and the extent to which reduced dimensionality confers a measurable advantage over traditional three-dimensional (3D) materials. Additionally, we discuss the critical influence of substrate interactions in 2D/3D heterostructures, which may offset or complicate the benefits of 2D architectures. By addressing these challenges and identifying future directions, this article outlines a roadmap toward the development of graphene-based electronics capable of surviving-and performing-in the most extreme radiation environments, where conventional materials are prone to failure and low-dimensional systems may thrive.