Optical Fiber Sensors in Ionizing Radiation Environments

Abstract

The present chapter addresses the use of optical fiber sensors (OFSs) in ionizing radiation environments. In this context, OFS research reflects (i) either the reliability of such sensors under radiation exposure and their capability to operate within prescribed limits (sensitivity, dynamic range, S/N, reproducibility, linearity, etc.) in order to act as transducers for specific quantities (temperature, humidity, strain, etc.) (ii) or, if they are subject to some degradation, the benefit of the irradiation-induced changes for developing radiation dosimeters or radiation monitors. OFSs are classified in extrinsic and intrinsic sensors, according to the role played by the optical fiber in the system. In the first case, the optical fiber acts as a light guide of the radiation-generated optical signal, while in the second situation, the fiber material constitutes the detecting medium, where light is produced under radiation exposure. Depending on the type of intrinsic sensor considered, some devices are structured inside the fiber and form the sensor. Intrinsic OFSs are further divided into discrete, quasi-distributed, and distributed sensing configurations. Discussion on OFSs in this chapter covers different fiber structures and materials, as they are reported in literature. Basic operating principles of these sensors are introduced to the reader excepting the cases when such concepts are detailed in other chapters. For reader’s convenience, an extended list of references was included in order to set the scene for a better understanding of the benefits and limits of employing OFSs in such circumstances. In most of the presented cases, applications of optical fiber sensors in radiation dosimetry and/or radiation monitoring are mentioned. The chapter targeted audience is formed by university students, technical personnel, and experts in specific fields (medicine, nuclear and space industries, operators of ionizing radiation sources) interested in the use of optical fibers for remote monitoring and control and in radiation reach environments, looking for the benefit associated with such sensors: immunity to electromagnetic fields, lack of fire risks, small size, low mass, and capability to handle multiparameter, multiplexed, or distributed measurements.