Design of a Large-Area Scintillation Detector Based on Wavelength-Shifting Fibers

[Results]: The photon collection probabilities of the side-mounted and bottom-mounted arrangements are 3.9% and 3.1% respectively. Although the side-mounted layout showed a slightly higher collection probability, the bottom-mounted layout offered greater advantages in sensitive area expansion, multi-detector splicing, and reduction of fiber bending loss. Following cooling, the temperature stability of the detector is significantly improved.

The detector demonstrates a measurable response to low-energy beta emitters such as 14C, and exhibited satisfactory response uniformity, a small dead zone, light weight, and modular splicing capability.  [Conclusions]: The proposed WLSF-based detector provides a lightweight, low-maintenance, and modular solution for radiation surface contamination monitoring. It mitigates the limitations of conventional detectors in simultaneously achieving a large sensitive area, response uniformity, portability, and low-energy beta response, and is suitable for applications in nuclear power, spent-fuel reprocessing, nuclear emergency response, and related scenarios.

Further optimization of WLSF layout density, optical-guide material selection, and optoelectronic-device coupling may expand its applicability in radiation detection systems.