Impact of storage induced outgassing organic contamination on laser induced damage of silica optics at 351 nm

International audienceThe impact of storage conditions on laser induced damage density at 351 nm on bare fused polished silica samples has been studied. Intentionally outgassing of polypropylene pieces on silica samples was done. We evidenced an important increase of laser induced damage density on contaminated samples demonstrating that storage could limit optics lifetime performances. Atomic Force Microscopy (AFM) and Gas Chromatography-Mass Spectrometry (GC-MS) have been used to identify the potential causes of this effect. It shows that a small quantity of organic contamination deposited on silica surface is responsible for this degradation. Various hypotheses are proposed to explain the damage mechanism. The more likely hypothesis is a coupling between surface defects of optics and organic contaminants

Qualification testing of an innovative system for monitoring particle contamination fallout

International audienceParticle fallout in cleanrooms is a primary concern for industries manufacturing critical products with surfaces highly susceptible to particulate contamination. Limited research has been conducted to measure the deposited particles in cleanroom. In the frame of the ISO 14644-3, this paper compares the traditional technique for particle fallout measurements using witness plates to a real-time and in situ measurement done by an innovative device: CLEAPART-100. The CLEAPART-100 detects the same contamination event as optical counters detect. The comparison with the settle plates observed under a microscope shows the loss of particles using that indirect measurement which is unacceptable for an accurate risk analysis assessment

Study of organic contamination induced by outgassing materials. Application to the Laser MégaJoule optics

International audienceOrganic contamination may decrease the targeted performances of coated surfaces. To study the contamination induced by surrounding materials, a method using a thermal extractor is presented in the first part of this work. Besides its normal operation (analyses of outgassing compounds from a material), this device is used in an original way to contaminate and decontaminate samples. Efficiency of contamination and decontamination protocols are assessed by automated thermal desorption and gas chromatography coupled with mass spectrometry and by secondary ion mass spectrometry coupled with a time of flight mass analyzer. This enables to study the contamination induced by a bulk material outgassing and to take in consideration the possible competition between outgassed species. This method is then applied to investigate contamination of Laser MégaJoule sol–gel coated optics by a retractable sheath. The impact of the temperature on the outgassing of the sheath has been highlighted. Increasing temperature from 30 to 50 • C enables the outgassing of organophosphorous compounds and increases the outgassing of oxy-genated compounds and phthalates. Chemical analyses of contaminated optics have highlighted affinities between the sol–gel coating and phthalates and organophosphorous, and low affinities with aromatics and terpens. Finally, samples with increasing levels of contamination have been realized. However a saturation phenomenon is observed at 90 ng cm–2

Quantifiers in Italian

Presenta le propriet\ue0 dei quantificatori in italiano, in un volume che raccoglie analoghe presentazioni per adyghe, basco, garifuna, tedesco, greco, ebraico, ungherese, giapponese, malgascio, cinese mandarino (Taiwan), pima, russo, telugu, armeno occidentale, wolof. Il punto di partenza \ue8 un questionario comune a tutti gli altri capitoli, che serve come base per presentare e discutere le peculiarit\ue0 sintattiche e semantiche dell'italiano

Effects of Al:Si and (Al+Na):Si Ratios on the Static Corrosion of Sodium-Boroaluminosilicate Glasses

International audienceUnderstanding alteration mechanisms of borosilicate glasses in aqueous media is essential to nuclear waste performance assessments to ensure radioisotopes are contained for extended durations. Aluminum is typically added to glass compositions to reduce the extent of alteration. However, previous work on 7-day durability tests has suggested that Al has a non-linear relationship with extent of alteration. The effects of Al:Si and (Al+Na):Si substitutions on glass durability were evaluated using series of glasses based on the International Simple Glass corroded in static conditions up to 13 months in deionized water at 90 °C. The alteration behavior was determined by measurement of element release in solution. The ⁓7-day alteration trends across the series were consistent with predicted trends. The 13 month results indicated overall alteration decreased as Al:Si ratios increased and was unaffected by changes in (Al+Na):Si except for the glass with the highest (Al+Na):Si ratio (ISG-A23N), which completely altered within 14 days. Frequent sampling and in-situ Raman measurements revealed ISG-A23N experienced several distinguishable alteration rate regimes within 7 days, forming a ⁓100 µm alteration layer and a NaSiAlO4 zeolite