Search results for "Effects"
showing 10 items of 2634 documents
Steady-State X-Ray Radiation-Induced Attenuation in Canonical Optical Fibers
2020
The so-called canonical optical fibers (OFs) are samples especially designed to highlight the impact of some manufacturing process parameters on the radiation responses. Thanks to the results obtained on these samples, it is thus possible to define new procedures to better control the behaviors of OFs in radiation environments. In this article, we characterized the responses, under steady-state X-rays, of canonical samples representative of the most common fiber types differing by their core-dopants: pure silica, Ge, Al, and P. Their radiation-induced attenuation (RIA) spectra were measured online at both room temperature (RT) and liquid nitrogen temperature (LNT), in the energy range [~0.6…
Transient and Steady-State Radiation Response of Phosphosilicate Optical Fibers: Influence of H2 Loading
2019
The radiation response of a phosphorus-doped multimode optical fiber is investigated under both transient (pulsed X-rays) and steady-state ( $\gamma $ - and X-rays) irradiations. The influence of a H2 preloading on the fiber radiation-induced attenuation (RIA) in the 300–2000-nm wavelength range has been characterized. To better understand the impact of this treatment, online behaviors of fiber samples containing different amounts of gas are compared from glass saturation (100%) to less than 1%. In addition to these in situ experiments, additional postirradiation spectroscopic techniques have been performed such as electron paramagnetic resonance or luminescence measurements to identify the…
Transient Radiation Responses of Optical Fibers: Influence of MCVD Process Parameters
2012
International audience; A dedicated set of fibers elaborated via the Modified Chemical Vapor Deposition (MCVD) technique is used to study the influence of composition and drawing parameters on their responses to an X-ray pulse representative of the radiation environments associated with Megajoule class lasers. These canonical fibers were designed to highlight the impact of these parameters on the amplitude and kinetics of the transient pulsed X-ray Radiation Induced Attenuation (RIA) at room temperature. From preforms differing by their core composition, three optical fibers were elaborated by varying the tension and speed during the drawing process. No or only slight RIA change results fro…
Pinch technique for Schwinger-Dyson equations
2007
40 pages, 11 figures.-- ISI Article Identifier: 000245922000041.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0611354
Time resolved photoluminescence associated with non-bridging oxygen hole centers in irradiated silica
2008
Abstract We report time resolved photoluminescence spectra of irradiated silica under excitation with a laser tunable in the visible and UV range. The investigated samples exhibit the emission band at 1.9 eV associated with non-bridging oxygen hole centers, whose spectral and kinetics properties do not depend on the kind of irradiation (γ, β and neutrons). The 1.9 eV luminescence decay follows a multi-exponential curve with a characteristic lifetime that increases from 8.9 μs to 10.4 μs on increasing the emission energy. This dependence accounts for the blue-shift of the emission band during its decay and is interpreted as due to the inhomogeneous properties of silica leading to a distribut…
Influence of the manufacturing process on the radiation sensitivity of fluorine-doped silica-based optical fibers
2011
International audience; In this work, we analyze the origins of the observed differences between the radiation sensitivities of fluorine-doped optical fibers made with different fabrication processes. We used several experimental techniques, coupling in situ radiation-induced absorption measurements with post mortem confocal microscopy luminescence measurements. Our data showed that the silica intrinsic defects are generated both from precursor sites and from strained regular Si-O-Si linkages. Our work also provides evidence for the preponderant role of the chlorine in determining the optical losses at about 3.5 eV. The results show that the manufacturing process of these fibers strongly af…
Irradiation induced defects in fluorine doped silica
2008
International audience; The role of fluorine doping in the response to UV pulsed laser and c radiation of silica preforms and fibers was studied using electron spin resonance (ESR) spectroscopy. Exposure to radiation mainly generates E0 centers, with the same effectiveness in fibers and in preforms. The E'concentration in F-doped silica fibers is found to increase with UV energy fluence till a saturation value, consistently with a precursor conversion process. These results show the fluorine role in reducing the strained Si–O bonds thus improving the radiation hardness of silica, also after drawing process.
Electron-Induced Upsets and Stuck Bits in SDRAMs in the Jovian Environment
2021
This study investigates the response of synchronous dynamic random access memories to energetic electrons and especially the possibility of electrons to cause stuck bits in these memories. Three different memories with different node sizes (63, 72, and 110 nm) were tested. Electrons with energies between 6 and 200 MeV were used at RADiation Effects Facility (RADEF) in Jyvaskyla, Finland, and at Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments (VESPER) in The European Organization for Nuclear Research (CERN), Switzerland. Photon irradiation was also performed in Jyvaskyla. In these irradiation tests, stuck bits originating from electro…
Tachyonic production of dark relics : a non-perturbative quantum study
2023
We study production of dark relics during reheating after the end of inflation in a system consisting of a non-minimally coupled spectator scalar field and the inflaton. We derive a set of renormalized quantum transport equations for the one-point function and the two-point function of the spectator field and solve them numerically. We find that our system can embody both tachyonic and parametric instabilities. The former is an expected result due to the non-minimal coupling, but the latter displays new features driven by a novel interplay of the two-point function with the Ricci scalar. We find that when the parametric instability driven by the two-point function takes place, it dominates …
Isotopic Enriched and Natural SiC Junction Barrier Schottky Diodes Under Heavy Ion Irradiation
2022
The radiation tolerance of isotopic enriched and natural silicon carbide junction barrier Schottky diodes are compared under heavy ion irradiation. Both types of devices experience leakage current degradation as well as single-event burnout events. The results were comparable, although the data may indicate a marginally lower thresholds for the isotopic enriched devices at lower linear energy transfer (LET). Slightly higher reverse bias threshold values for leakage current degradation were also observed compared to previously published work.