Search results for " X-ray irradiation"
showing 3 items of 3 documents
X-ray irradiation effects on a multistep Ge-doped silica fiber produced using different drawing conditions
2011
International audience; We report an experimental study based on confocal microscopy luminescence (CML) and electron paramagnetic resonance (EPR) measurements to investigate the effects of the X-ray (from 50 krad to 200 Mrad) on three specific multistep Ge doped fibers obtained from the same preform by changing some of the drawing conditions (tension and speed). CML data show that, both before and after the irradiation, Germanium Lone Pair Center (GLPC) concentrations are similarly distributed along the diameters of the three fibers and they are partially reduced by irradiation. The irradiation induces also the Non Bridging Oxygen Hole Center (NBOHC) investigated by CML and other paramagnet…
X-ray irradiation effects on a specific multistep Ge-doped fiber
2010
International audience; The study of point defects generation in optical fibers plays an important role with regards to their use and application in different domains. Their design and elaboration processes (dopants type, concentration, refractive index profile, drawing conditions...) govern their responses and more generally their radiation hardness [1]. In this work we investigated, the influence of 10 keV X-ray irradiations on a set of specific germanosilicate optical fibers elaborated from the same preform at different drawing conditions. The germanium doping levels along the fiber core diameter was specifically designed to follow a two-step distribution in order to highlight the Ge-con…
The young hard active Sun: soft X-ray irradiation of tryptophan in water solutions
2010
AbstractThe X-ray emission of the young Sun was much harder and intense than today and might have played a significant role in the evolution of complex organics in protoplanetary environments. We investigate the effects of soft X-rays on tryptophan molecules in aqueous solutions at room temperature. As results of the irradiation experiments we detect several light species indicative of fragmentation, together with large molecular structures such as tryptophan dipeptide and tripeptide. Complexification is more evident in H2O solution than in D2O, probably due to isotopic effects. The abundances of peptides depend on the irradiation dose and decrease with increasing energy deposition. Radical…