Neutrinos Caught on Camera: First Prototype of New Elementary Particle Detector Tested

Researchers from ETH Zurich and EPFL have successfully tested the first prototype of a new elementary particle detector capable of capturing ultrafast, three-dimensional and high-resolution images of particles such as neutrinos in large volumes of unsegmented scintillator material.

The detector represents a significant departure from traditional methods that rely on finely segmented scintillator materials, where each small unit emits light when charged particles pass through and the resulting photons are collected via optical fibers for analysis. As experiments scale up, this segmentation-based approach becomes increasingly complex and costly.

Instead, the new prototype uses a single, solid block of scintillator material. Particle pathways are reconstructed using advanced optics and precision timing electronics, enabling detailed 3D tracking without the need for physical segmentation.

The team, led by Till Dieminger, Saúl Alonso-Monsalve, and Davide Sgalaberna from ETH Zurich’s Department of Physics, collaborated with Kodai Kaneyasu, Claudio Bruschini, and Edoardo Charbon from EPFL’s Advanced Quantum Architecture Lab in the School of Engineering to develop and test the system.

Their work, which includes both experimental demonstration and comprehensive simulations, has been published in Nature Communications. The study illustrates how the monolithic detector system can achieve high-resolution imaging in large, unsegmented scintillator volumes, addressing a key challenge in modern particle physics experiments.

Three-dimensional tracking of elementary particles is essential in experiments studying weakly interacting particles like neutrinos and certain dark matter candidates. Improvements in detector volume and spatial resolution directly enhance sensitivity to the rare processes that produce these particles.

Similar demands for precise 3D imaging apply to calorimeters used in collider experiments, where understanding particle interactions requires accurate reconstruction of particle trajectories and energy deposition.

By eliminating the need for millions of individual scintillator cubes and tens of thousands of optical fibers — such as the approximately two million cubes and 60,000 fibers used in the T2K neutrino-oscillation experiment in Japan — the new approach could significantly reduce the complexity, cost, and maintenance burden of large-scale particle detectors.

The successful test of this prototype marks a step toward more scalable and efficient detection technologies for future neutrino experiments and other applications requiring high-precision particle tracking in dense materials.