Position-dependent light yield in short, coated SCSF-78 scintillating fibers

Abstract

In fibers made from organic plastic scintillators, a combination of extrinsic and intrinsic effects results in the attenuation of light and thus in a position-dependent light yield. The trapping of photons can further be affected if fibers are coated with or wrapped in a light-absorbing or reflecting material to suppress optical cross-talk. These effects have frequently been studied for long (>0.5m) fibers, yet little data is available for shorter ones. We experimentally studied the position-dependent light yield of single-cladded Kuraray SCSF-78 fibers with lengths of <10cm and tested the effect of different cross-talk-preventing materials. Contrary to the often acceptable simplification that light is transmitted in the fiber core alone, we found that photons trapped by the protective cladding significantly contribute to the light transmission in short fibers. In this paper, we perform an in-depth characterization of the position-dependent light yield of fibers sputter-coated with aluminum and wrapped in aluminum foil using a double-exponential attenuation function. Finally, we compare our findings to a simple photon transport model.