Investigation of gamma-ray detection with an opaque liquid scintillator

Opaque scintillators are highly scattering such that scintillation photons are probabilistically confined to a small sub-region of the detector. The light is then transported out of the detector via wavelength-shifting fibers. We present the experimental results with a prototype detector that is 1 liter in volume and has 32 wavelength-shifting fibers, each connected to a pixel of a multi-anode photomultiplier tube and read out by a separate digitizer channel. The detection medium is linear-alkylbenze with wavelength shifting fluors and paraffin wax to induce opacity. We compare the spectra of gamma rays from two radioisotopes to show they are differentiable. We show the capability of the detector for source localization through observation of the spatial distribution of light. Lastly, we investigate the resolution in reconstructing the event position in a direction transverse to optical fibers.