Performance evaluation of Luxium Solutions BCF-XL wavelength-shifting fibers

TL;DR

This work evaluates Luxium BCF-XL single-clad WLS fibers (BCF-92XL, BCF-9929AXL, BCF-9995XL) against Kuraray Y-11, combining laser-based measurements of decay time and attenuation length with electron-beam tests to assess light yield and time resolution in EJ-204 scintillator setups. The results show intrinsic decay times for BCF-XL around $τ \approx 2.1$ ns, far shorter than Y-11's $τ \approx 7.44$ ns, while attenuation lengths are comparable within a 3.2 m window. In beam tests, light yields are about 60% of Y-11 due to single-clad structure, but time resolutions improve to roughly $1.06-1.11$ ns for BCF-XL versus $1.52$ ns for Y-11, indicating faster timing with preserved timing precision. Overall, the BCF-XL series offers notably faster timing with competitive attenuation characteristics and practical light yields, making them attractive for fast scintillator-based detectors.

Abstract

We evaluate the performance of single-clad wavelength-shifting fibers newly developed by Luxium Solutions, BCF-92XL, BCF-9929AXL, and BCF-9995XL and compare them with the multi-clad Kuraray Y-11 fiber. The BCF-XL fibers exhibit faster decay times (92XL: $2.10\pm0.01$ ns, 9929AXL: $2.10\pm0.02$ ns, 9995XL: $2.41\pm0.03$ ns) than Y-11 ($7.44\pm0.06$ ns). The attenuation lengths are comparable to that of Y-11 within the measurement range up to 3.2 m. When coupled to an EJ-204 plastic scintillator, the BCF-XL fibers achieve superior time resolution while maintaining light yields comparable to those expected for a single-clad Y-11 fiber.

Figures (15)

• Figure 1: Schematic diagram (top) and photographs (bottom) of the laser-based measurement system. The main components include a laser diode, a digitizer, and a readout circuit on which an MPPC is mounted. After the dark box is closed, it is covered with a black sheet to ensure complete light shielding.
• Figure 2: Schematic diagram (left) and photograph (right) of the readout circuit. $V_{in}$ is the bias voltage applied to the MPPC, which is set to approximately 57.5 V.
• Figure 3: Photographs of the laser injection assembly. The optical fiber is connected to the jig via an FC connector. The WLS fiber is embedded in the groove of the jig and is secured by the cover.
• Figure 4: A waveform of a single-photon event. The horizontal axis shows the time (ns), and the vertical axis shows the ADC count of the digitizer. The dashed blue horizontal lines show the pedestal, the half-maximum level, and the pulse height. The red line is the interpolation line used to determine the waveform timing.
• Figure 5: A 2D histogram of pulse height versus integrated ADC. The peak in the lower-left corner corresponds to the 0 p.e. events, while the peak around a pulse height of approximately 70 ADC and an integrated ADC of about 1000 corresponds to the 1 p.e. events. Distributions originating from afterpulses and optical crosstalk can be seen in the upper-right area. The events within the red-boxed region are used for the decay time analysis.