Radiation Effects in Optical Materials and Photonic Devices

The chapter continues previous reviews on radiation effects in optical fibers and on the use of optical fibers/optical fiber sensors in radiation monitoring, published by InTech in 2010 and 2012, by referring to radiation effects in optical materials, with an emphasis on those operating from visible to mid-IR, and on some photonic devices such as optical fibers for amplifiers, fiber Bragg gratings and long period gratings. The focus is on optical materials and fiber-based devices designed for both terrestrial and spaceborne applications. For the presented subjects, an overview of available data on X-rays or gamma rays, electron beams, alpha particles, neutrons, and protons effects is provided. In addition, comments on dose rate, dose, and/or temperature effects on materials and devices degradation under irradiation are mentioned, where appropriate. The optical materials and photonic devices reliability under ionizing radiation exposure is discussed as well, as the opportunities to use them in developing radiation sensors or dosimeters. The chapter includes an extensive bibliography and references to last published results in the field. Novel proposed applications of photonic devices in charged particle beam diagnostics, quasi-distributed radiation field mapping and the evaluation of radiation effects in materials for mid-IR spectroscopy are briefly introduced to the reader

Optical fibers and optical fiber sensors used in radiation monitoring

peer-reviewedBy 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).PUBLISHEDpeer-reviewe

Chapter Optical fibers and optical fiber sensors used in radiation monitoring

Communications engineering / telecommunication

Optimized Spectrometers Characterization Procedure for Near Ground Support of ESA FLEX Observations: Part 1 Spectral Calibration and Characterisation

The paper presents two procedures for the wavelength calibration, in the oxygen telluric absorption spectral bands (O2-A, λc = 687 nm and O2-B, λc = 760.6 nm), of field fixed-point spectrometers used for reflectance and Sun-induced fluorescence measurements. In the first case, Ne and Ar pen-type spectral lamps were employed, while the second approach is based on a double monochromator setup. The double monochromator system was characterized for the estimation of errors associated with different operating configurations. The proposed methods were applied to three Piccolo Doppio-type systems built around two QE Pros and one USB2 + H16355 Ocean Optics spectrometers. The wavelength calibration errors for all the calibrations performed on the three spectrometers are reported and potential methodological improvements discussed. The suggested calibration methods were validated, as the wavelength corrections obtained by both techniques for the QE Pro designed for fluorescence investigations were similar. However, it is recommended that a neon emission line source, as well as an argon or mercury-argon source be used to have a reference wavelength closer to the O2-B feature. The wavelength calibration can then be optimised as close to the O2-B and O2-A features as possible. The monochromator approach could also be used, but that instrument would need to be fully characterized prior to use, and although it may offer a more accurate calibration, as it could be tuned to emit light at the same wavelengths as the absorption features, it would be more time consuming as it is a scanning approach

Gamma radiation measurements using an optical fiber laser

Trabajo presentado a la 26th International Conference on Optical Fiber Sensors. Suiza, 2020A fiber ring laser cavity configuration was used to analyze the effect of gamma-irradiation over the performance of different types of erbium doped fibers. Preliminary results validates this method to monitor gamma-radiation in real time.Financial support from the Spanish Comisión Interministerial de Ciencia y Tecnología within project TEC2016- 76021-C2-1-R and FEDER funds from the European Union are acknowledged. The reported investigations were performed in the frame of the COST Action MP 1401

Investigation of Changing Volt-Ampere Characteristics of AlGaInP Heterostructures with Multiple Quantum Wells under Ionizing Radiation

The results of research into degradation of volt-ampere characteristics of light emitting diodes produced on the base of AlGaInP heterostructures with multiple quantum wells are presented on the example of light emitting diodes (emission wavelengths 623 nm and 590 nm) under gamma quantum and fast neutron radiation in passive powering mode. The shifts of volt-ampere characteristics into the higher voltage range have been observed in conditions of increasing neutron fluence and radiation dose. The observed increase in the resistance of ohmic contacts is caused by the rising resistance of adjacent area, which in its turn results from the changing mobility of charge carriers. The latter varies with the growth of introduced defects under irradiation. Two different areas of current generation have been identified. A mechanism of current generation depends on injected charge carriers in the range of mid-level electron injection. Moreover, the range of high electron injection is distinguished by changing resistance of light emitting diode cores alongside with current generation conditioned by charge carrier injection