The Stochastic Light Confinement of LiquidO

TL;DR

LiquidO introduces a novel opaque medium technique that stochastically confines light around energy depositions, enabling high-resolution, real-time imaging in particle detection with potential applications in physics research.

Contribution

The paper demonstrates LiquidO's innovative use of opaque media for light confinement, preserving event topology and enabling real-time imaging at the MeV scale, which surpasses traditional transparent media methods.

Findings

Achieved 90% light confinement within a 5 cm radius sphere in a 10-litre prototype.

Demonstrated high-resolution imaging capabilities with a custom opaque scintillator.

Explored timing differentiation between Cherenkov and scintillation light.

Abstract

Light-based detectors have been widely used in fundamental research and industry since their inception in the 1930s. The energy particles deposit in these detectors is converted to optical signals via the Cherenkov and scintillation mechanisms that are then propagated through transparent media to photosensors placed typically on the detector's periphery, sometimes up to tens of metres away. LiquidO is a new technique pioneering the use of opaque media to stochastically confine light around each energy deposition while collecting it with an array of fibres that thread the medium. This approach preserves topological event information otherwise lost in the conventional approach, enabling real-time imaging down to the MeV scale. Our article demonstrates LiquidO's imaging principle with a ten-litre prototype, revealing successful light confinement of 90% of the detected light within a 5 cm radius sphere, using a custom opaque scintillator with a scattering length on the order of a few millimetres. These high-resolution imaging capabilities unlock opportunities in fundamental physics research and applications beyond. The absolute amount of light detected is also studied, including possible data-driven extrapolations to LiquidO-based detectors beyond prototyping limitations. Additionally, LiquidO's timing capabilities are explored through its ability to distinguish Cherenkov light from a slow scintillator.