Performance characterization of functional fiber detectors: scintillating fibers with embedded photodiodes

Abstract

In various operational scenarios, the effectiveness of existing radiation detection technologies is frequently hindered by limitations in terms of portability, adaptability, and cost-effectiveness. Bridging this critical gap necessitates innovative approaches, and thus, this thesis proposes a solution in the form of radiation-sensitive functional fabrics. This innovative concept involves the integration of avalanche photodiodes within scintillating fibers, thereby engendering a detector that is not only lightweight and flexible, but also remarkably affordable.

The foundation of this methodology revolves around the utilization of a convergent thermal draw process, an intricate technique that yields millimeter-thick fibers encompassing all essential detector components. Through a series of iterative experiments, a limited number of fibers embedded with silicon photomultipliers (SiPMs) have been produced for study. The light attenuation length for each prototype of the functional fiber detectors is measured. In addition, the SiPMs used in this work have been carefully calibrated to obtain the correspondence between the measured energy and the number of photoelectrons detected by the SiPM. This allows for determination of the detection threshold of the functional fiber detectors. Furthermore, a crucial facet of this research involves the calibration of the SiPMs. This calibration process is executed to establish a precise correspondence between the energy detected and the count of photoelectrons registered by the SiPM. The calibration allows for the determination of the detection threshold of the functional fiber detectors, thus underpinning their effectiveness in radiation detection.

After obtaining a clear understanding of the performance, future plans include more complicated multi-fiber arrays and fabrics. The potential applications of functional fiber detectors include identification of unknown radioactive sources, wearable detectors for warfighters and first responders, and flexible detector arrays for arms control applications.