A passing particle leaves a flash of light in a long transparent bar — a scintillator. Inside the bar, like threads in a rope, thin fibers are stretched to collect this light and channel it to a sensor. Particle detectors have worked this way for decades.

Previously, the accuracy of such a detector was tied to the distance between fibers: a particle could pass anywhere between them, leaving uncertainty. Now physicists have tested triangular-shaped bars. It turns out that by comparing how brightly neighboring fibers flash, you can calculate the point of passage much more precisely — ten times more precisely than just by the fiber spacing.

The scientists tested the method on a test particle beam and compared it with a computer model. The results matched. This means that in future experiments, detectors can be built with fewer fibers but better accuracy — saving materials and simplifying the design.