Evaluation of an outer-layer scintillating fiber designed for position-sensitive α-particle detectors

Wavelength-shifting fibers have enabled the development of large-area, position-sensitive detectors due to their excellent attenuation length and light-guiding properties. We characterized a newly developed outer-layer scintillating (OLS) fiber designed for α-particle detection, termed OLS-14-2. The OLS-14-2 fiber features an enhanced scintillating outer layer that provides improved light output and shorter fluorescence decay time compared to its predecessor, OLS-3. The decay time was reduced from 7.45 to 2.27 ns, and the increased scintillatior thickness enabled efficient energy deposition from α-particles. We also demonstrated the applicability of a 2.55-m OLS-14-2 fiber in a one-dimensional position-sensitive detector. The measurement system achieved an average time resolution of 2.07 ns and spatial resolution of 160 mm. The detector resolution was maintained even when an aluminized Mylar film was used as a light shield. These findings validate the OLS-14-2 fiber as a promising sensor for position-sensitive α-particle detection.