Event-by-event track imaging of charged particles with an ultrafast plenoptic camera
Modern elementary particle detectors often require high-resolution three-dimensional particle tracking in large dense active volumes, which is difficult to achieve in standard devices without an extremely fine segmentation. In recent work, a plenoptic camera instrumented with a single-photon avalanche-diode array, called PLATON, demonstrated to image individual visible photons generated in monolithic scintillating material and reconstruct their three-dimensional origin from a single-event exposure, opening a route to high-spatial-resolution detection of elementary particles in unsegmented scintillator. However, those tests aimed to address photon sources of essentially zero geometric extent. In this work we close the gap to the tracking regime. First, we calibrated the PLATON prototype using light tracks in an organic plastic scintillator induced by a femtosecond infrared laser via two-photon absorption and characterised its capability to reconstruct photon-starved 3D lines with a novel algorithm, achieving good agreement with custom Monte Carlo simulation. Finally, the PLATON prototype was exposed to a test beam of pions at the CERN Proton Synchrotron. For the first time, a plenoptic detector system was successfully used to detect and reconstruct the 3D tracks of elementary particles from 2D photon-starved images on an event-by-event basis marking a transformative approach to high-resolution measurements.