The reflectance curves for a variety of plastics (and Bicron's reflective paint as a standard) have been measured. These are plotted with the emission spectra of two scintillator types as overlays (scaled to an arbitrary height). The Bicron 517 scintillator is the current favorite; the 404 scintillator was represented to me (RWH) as more typical of solid scintillators but possible in a liquid. Obviously the shift to shorter wavelengths is not particularly effective in the the proposed configuration due to the steep cut-off in R below 420 nm.
The same curves are shown zoomed in to the relevant region. The scale is restricted to R>75% and the wavelength range where the Bicron 517 emission is >20% of its maximum value (402-474nm).
The waveshifting fiber absorption (blue) and re-emission (green) spectra for Bicron 91a and Bicron 92 fibers is plotted from numbers taken from a similar plot in the Bicron literature. Again the scintillator emission spectra are shown for comparision.
