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We characterized the responses of three erbium-doped fibers with slightly different concentrations of rare-earth ions (240-290 ppm) and Al2O3 (7-10 wt.%) during proton and γ-ray exposures. We have simultaneously measured the radiation-induced attenuation (RIA) around the Er3+ ion pumping wavelength (980 nm) and the associated changes of the Er3+ emission around 1530 nm. The three erbium-doped fibers show similar radiation responses. All fibers exhibit RIA levels between 9 × 10-3 and 1.7 × 10-2 dB m-1 Gy-1 at 980 nm and between 4 × 10-3 and 1.1 × 10-2 dB m-1 Gy-1 at 1530 nm. Protons and -y-rays lead to similar radiation damages, with small differences between the protons of different energies (50 MeV and 105 MeV). Furthermore, we have performed online measurements of the spectral dependence of RIA from 600 to 1600 nm and offline measurements from 1200 to 2400 nm. The three fibers exhibit the same spectral response. Losses decrease monotonically from the visible to the infrared part of the spectrum. We have performed spectral decomposition of these RIA curves with the help of absorption bands previously associated with radiation-induced point defects. Our analysis shows that the main part of the RIA (600-1700 nm) in erbium-doped glass can be explained by the generation of Al-related point defects. The other defects related to the germanium and phosphorus doping of the silica seem to have a lower contribution to the induced losses. The Er3+ ion properties seem to be mainly unaffected by proton exposure, suggesting a solvation shell around the Er3+ ion formed by Al2O3 species. [ABSTRACT FROM AUTHOR]

The proton irradiation effects on n-MuGFET devices with three different geometries (single fin, wide fin and multiple fin) are studied. Also, the effect of tensile strain in the fin on the radiation behavior is investigated. A fundamental difference in the radiation behavior between the non-strained and the strained devices is found. The degradation of the strained devices is most affected by the mobility decrease of the backside transistor. The non-strained devices show a much lesser back gate mobility degradation. For these devices the creation of positive oxide traps is dominant. This shifts the onset of the back channel to lower gate voltages, inducing a transconductance increase at intermediate gate voltages. This effect is less pronounced for single fin MuGFETs. At higher gate voltage, the transconductance decreases for the strained and increases for the non-strained transistors. [ABSTRACT FROM AUTHOR]

Abstract: Several single mode silica-based fibers with different levels of erbium concentrations have been tested under 60Co gamma radiation. Irradiation has been performed at a dose-rate of ∼30Gy/h to a total dose of ∼2kGy. Transmission spectra were measured in situ in a spectral range from 1250 to 1630nm. The measurements show no detectable change in the Er-ions luminescence and absorption spectrum profiles, while a significant (∼dB/m/kGy at 1530nm) increase in transmission losses is attributed to the silica host matrix modifications. This conclusion is drawn based on the post-irradiation photo-luminescence analyzes realized with a confocal micro-spectrometer (514.5nm excitation, P ∼2mW). [Copyright &y& Elsevier]

Future maintenance tasks of the International Experimental Thermonuclear fusion Reactor (ITER) will require communication links between the remotely operated equipment in the reactor vessel and the control room, that are radiation tolerant up to MGy dose levels. We therefore assessed the DC behaviour of a COTS SiGe heterojunction bipolar transistor (HBT) under gamma radiation up to more than 4 MGy. The DC current gain (β) presents a limited loss of about 30% for a base current of 100 μA. Our in-situ measurements allowed us to adapt the manufacturer's SPICE model and account for these radiation effects. Circuit-hardened driving electronics for both photonic transmitters and receivers can hence be designed. [ABSTRACT FROM AUTHOR]

The radiation behavior of a commercially available Er-doped fiber is evaluated under varying gamma dose rates with in-situ spectral loss measurements. Complementary post-irradiation photoluminescence measurements allow us to better under- stand the radiation effects. Our results suggest that the microscopic enviromnent of the Er3+ ions is not much affected by the gamma irradiation, unlike the host matrix. We discuss the impact for potential applications of these commercially available fibers in radiation environments. [ABSTRACT FROM AUTHOR]

The future International Thermonuclear Experimental Reactor (ITER) requires remote handling tools for its maintenance that will operate in a harsh environment. The numerous instrumentation cables for this maintenance equipment call for (de)multiplexing solutions, in order to reduce the umbilical size. Fibre-optic data links, using commercial-off-the-shelf (COTS) components, are seriously considered as a radiation tolerant solution, offering wavelength encoded multiplexing possibilities. However, an adapted modus operandi for a reliable assessment of this evolving technology is needed, to enable their long-term implementation in a radiation environment. In this paper, we present a methodology towards qualification methods for these instrumentation data links, and illustrate it with results obtained for different individual components. These results should enable the future design of robust architectures for communication links. [Copyright &y& Elsevier]

Provides information on a study which evaluated the radiation resistance of fiberoptic links. In-depth look at light emitting diodes, pin-type photodetectors and optical fibers; Details on the ...-ray irradiation response; Methodology used to conduct the study; Results of the study.