Image Courtesy: ETH Zurich/Sgalaberna Group
Researchers in Switzerland have developed a novel camera-based particle detector capable of reconstructing the three-dimensional paths of nearly invisible particles inside a solid block of material. The proof-of-concept system could simplify future particle detectors while maintaining the high precision needed for experiments involving neutrinos, dark matter, and other elusive particles. The findings were published in Nature Communications.
Particle detectors typically rely on scintillators, materials that emit tiny flashes of light when struck by charged particles. To determine where those particles traveled, scientists usually divide the detector into millions of small segments connected by thousands of optical fibers. While highly accurate, these detectors become increasingly expensive and difficult to build as they grow larger.
A team from ETH Zurich and EPFL has taken a different approach. Instead of segmenting the detector, the researchers created a prototype called PLATON that uses a plenoptic, or light field, camera to determine where faint flashes of light originate inside a single, unsegmented block of scintillator.
The system combines a micro-lens array with a SwissSPAD2 single-photon avalanche diode sensor capable of detecting individual photons. Unlike conventional cameras, the setup captures both the intensity and direction of incoming light, allowing it to reconstruct particle tracks in three dimensions. The sensor also records photons only during carefully timed windows, helping eliminate background noise.
Laboratory tests showed the prototype could accurately reconstruct electron interactions using as few as five detected photons. Simulations closely matched the experimental results, giving researchers confidence in the detector’s performance.
The team is now developing an upgraded version featuring improved photon sensitivity and sub-nanosecond timing. Future models will assign an individual timestamp to every detected photon, improving the accuracy of particle-track reconstruction.
Researchers also integrated a Transformer-based neural network to analyze photon patterns and reconstruct particle interactions. Simulations suggest that an upgraded 10-centimeter detector could achieve spatial resolution below one millimeter while effectively identifying neutrino interactions. Even a detector scaled to one cubic meter could deliver resolution comparable to today’s most advanced scintillator systems without requiring millions of individual components.
Beyond particle physics, the technology could have significant medical applications. The researchers have already filed patents covering the use of PLATON in positron emission tomography (PET), raising the possibility that innovations developed for fundamental physics could eventually improve medical imaging.
