Spectral response of scintillating fibers

The spectral response of PHT-0044 (blue) and BCF-20 (green) scintillating fibers was measured as a function of wavelength using a UV LED. It was observed that significant spectral strength from the PHT-0044 fibers was missing compared to manufacturer's specifications at the origin of the source, shifting the peak value of the spectrum to significantly higher values in wavelength. In contrast, the corresponding shift for the BCF-20 fibers was minimal. The mechanisms responsible for the observed behavior are discussed herein. Moreover, the attenuation length for each fiber type was extracted and studied as a function of wavelength. Finally, the measured fiber spectra were convolved with the wavelength response from a typical bi-alkali photomultiplier as well as a green-sensitive silicon photomultiplier and compared.