Disentangle the degenerate contributions to absolute light collection

Determine separately the contributions of the NoWaSH scintillator’s absorption length, scattering length, wavelength-shifting dye quantum yield, and fiber or optical-coupling imperfections to the measured absolute light collection.

Background

The optical simulation contains several parameters that affect the absolute number of detected photons in similar or degenerate ways. The measured data constrain only their combined effect, preventing the experiment from independently identifying the scintillator transport properties, wavelength-shifting efficiency, and coupling losses.

Resolving these contributions is important for transferring the BPULSE light-yield measurement to future LiquidO detectors and for validating optical models used for vertex and timing reconstruction.

References

Predictions of absolute light collection are not used because coefficients that set the collection scale are unmeasured and mutually degenerate: the absorption and scattering lengths of the scintillator, the quantum yield of the WLS dye, and imperfections in fiber/coupling. The data constrain only their combination; separating them is left to future studies.

— Energy, vertex, and time response of a LiquidO detector with an opaque-scintillator target to Compton-tagged electrons  (2610.18849 - Collaboration et al., 13 Oct 2026) in Section 3.2, “Optical and Sensor Model”