Highly Radiation Sensitive Type IA FBGs for Future Dosimetry Applications

Opto-Mechanical Fiber Sensing of Gamma Radiation

“…The results provide the basis for optical fiber sensors of ionizing radiation [10,11,[13][14][15][16][17][18][19][20][21]. Most sensors monitor the effects of radiation on optical properties of the fiber, such as induced attenuation or refractive index variations [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. For example, attenuation in a standard single-mode fiber at 1,550 nm wavelength increased to 42 dBkm -1 following exposure to 7.3 Mrad of gamma radiation from a 60 Co source [24].…”

“…The effects of ionizing radiation on optical fibers have been studied for over 45 years [9], and they are investigated over fibers installed in several large-scale facilities [10][11][12]. The results provide the basis for optical fiber sensors of ionizing radiation [10,11,[13][14][15][16][17][18][19][20][21]. Most sensors monitor the effects of radiation on optical properties of the fiber, such as induced attenuation or refractive index variations [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…Despite much effort and progress, fiber-optic sensors of ionizing radiation still face several challenges. Attenuation and index changes depend on multiple metrics such as radiation type, energy, overall dose, and rate [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], thus the unambiguous interpretation of results can become difficult. In addition, radiation effects may be influenced by the presence and concentration of trace dopants in the fibers, and by the history of previous exposures and recovery [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…Attenuation and index changes depend on multiple metrics such as radiation type, energy, overall dose, and rate [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], thus the unambiguous interpretation of results can become difficult. In addition, radiation effects may be influenced by the presence and concentration of trace dopants in the fibers, and by the history of previous exposures and recovery [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Radiation effects on optical fibers are also characterized by cross-sensitivities to other environmental conditions such as temperature [30][31][32].…”

Interrogation of a cascaded FBG sensor using a wavelength-to-delay mapping technique

“…In multiplexed sensors, known as quasidistributed sensors too, an amount of discrete sensors, like interferometers [2] or FBGs [3], are cascaded along the same fiber. FBGs are extensively used due to both their mature fabrication technology and versatility to sense a variety of quantities, such as strain [4], temperature [3], pressure [5] or radiation [6]. Two broad groups of techniques are routinely used to interrogate such devices, namely, optical frequency domain reflectometry (OFDR) and optical time domain reflectometry (OTDR).…”