Optical Fibres for Radiation Dosimetry
The use of ionising radiation in a wide range of areas, from industrial processes to medical applications, has become increasingly significant in recent years. Radiation dosimetry, the measurement of absorbed dose delivered by ionising radiation, is funda
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Abstract The use of ionising radiation in a wide range of areas, from industrial processes to medical applications, has become increasingly significant in recent years. Radiation dosimetry, the measurement of absorbed dose delivered by ionising radiation, is fundamental to these radiation processes, ensuring tight control on radiation processes and the safety of personnel. As such it is the focus of much recent research to develop novel dosimeters and to improve dosimetry systems, be it increasing the sensitivity, providing real-time measurements or significantly reducing the costs. The inherent properties of optical fibres lend themselves to be used with great success in monitoring ionizing radiation. Optical fibres provide the means whereby real-time in situ monitoring of radiation doses can be realised, and offer numerous advantages over conventional methods, such as electrochemical and semiconductor sensors. Of significant advantage is the optical fiber’s immunity to electromagnetic and chemical interferences and their ability to monitor remotely, whereby the sensor can be placed several hundred metres from the control electronics. This means that they can be employed in harsh environments, such as in high-radiation-level areas in the vicinity of a nuclear reactor or gamma sterilisation facility. The small dimensions and light weight of optical fibres also provide for many opportunities for such sensors in personal dosimetry and medical applications. This chapter will discuss some of the key optical fibre based sensing techniques used in radiation dosimetry and outline their implementation in the different application areas of ionising radiation.
1 Introduction The most significant feature of an optical fibre dosimeter is that the dose information is transmitted using optical signals as opposed to electrical signals. Consequently, optical fibres are immune to electrical and electromagnetic interferences, S. O’Keeffe (✉) University of Limerick, Limerick, Ireland e-mail: [email protected] © Springer International Publishing Switzerland 2017 I.R. Matias et al. (eds.), Fiber Optic Sensors, Smart Sensors, Measurement and Instrumentation 21, DOI 10.1007/978-3-319-42625-9_7
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which can be a problem for many electronic dosimeters. Electric dosimetry systems often require a high voltage power supply and must have good electrical insulation. This insulation is known to degrade over time due to a number of radiation related phenomena, such as radiation induced electrical conductivity. This degradation can seriously affect the stability of the system. Another phenomenon, radiation induced electromotive force, generates electric noise that can interfere with the signal transmitting the dose information [1]. The ability to remotely monitor radiation is also an advantage of optical fibres. The sensor can be placed several hundred metres from the control electronics, which means that they can be employed in harsh environments, such as in high-radiation-level areas in the vicinity of a nuclear reactor. Optical fibre
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