Low-cost radioactivity monitoring with scintillating fibers and silicon photomultipliers

A new detector technology was developed, particularly suitable for low-cost radioactivity monitoring in radwaste storage sites. It consists of a scintillating optical fiber coupled at each end to a silicon photomultiplier (SiPM). The single-photon sensitivity of the SiPM, along with the left-right coincidence constraint, allows the achievement of a reasonable sensitivity to gamma radiation even though a thin 1-mm-diameter plastic scintillating fiber is used. Simulation results are in perfect agreement with the measured behavior, and several implementations are under way. The possibility of choosing the fiber length and shape makes them very flexible both conceptually and mechanically. Any improvement in the SiPM development technology reflects immediately into an improvement in the detector performance.