Optical Fibers and Optical Fiber Sensors Used in Radiation Monitoring

Abstract

By their very nature, optical fibers and, by extension, intrinsic and extrinsic optical fiberbased sensors are promising devices to be used in very different and complex environments considering their characteristics such as: capabilities to work under strong electromagnetic fields; possibility to carry multiplexed signals (time, wavelength multiplexing); small size and low mass; ability to handle multi-parameter measurements in distributed configuration; possibility to monitor sites far away from the controller; their availability to be incorporated into the monitored structure; wide bandwidth for communication applications. In the case of the optical fibers, the possibility to be incorporated into various types of sensors and actuators, free of additional hazards (i.e. fire, explosion), made them promising candidates to operate in special or adverse conditions as those required by space or terrestrial applications (spacecraft on board instrumentation, nuclear facilities, future fusion installations, medical treatment and diagnostics premises, medical equipment sterilization). Major advantages to be considered in using optical fibers/optical fiber sensors for radiation detection and monitoring refer to: real-time interrogation capabilities, possibility to design spatially resolved solutions (the capability to build array detectors), in-vivo investigations (i.e. inside the body measurements). As information on the behavior and operation of optical fibers/optical fiber sensors under irradiation conditions are scattered over a great variety of journal papers and conference contributions dealing with many different fields (nuclear science and engineering; measurement science; material science; radioprotection; nuclear medicine and radiology; sensor design; radiation dosimetry; fusion installations concepts; particle accelerators; astrophysics and space science; defense and security; lasers, optics, optical fibers and optoelectronics; physics and applied physics; scientific instrumentation; radiation effects) we decided to design this book chapter as a comprehensive review on the subject. The chapter opens with some general considerations on the radiation–matter interaction, and continues with a review of irradiation effects on different types of optical fibers (silica optical fibers, plastic optical fibers, special optical fibers), effects which can be considered when radiation sensors are developed. The next issue addressed refers to environments where optical fibers/optical fiber sensors are employed for radiation monitoring/