Results Of Round Robin Test Research Articles

106-μm laser damage of optical coatings: regression analyses of round-robin test results

The laser-induced damage thresholds of four different coating designs obtained with three to six samples each at eight laboratories involved in a round-robin experiment were evaluated by means of multiple regression analyses for the two main independent parameters: pulse width τ and beam diameter d [ K. H. Guenther , Appl. Opt.23, 3743 ( 1984).] The analyses show that the F vs τ1/2 relationship, with F being the damage threshold energy density (J/cm2) known from other experiments also holds for this one. The F vs d−m scaling law, however, yields only rather weak powers of m = 0.015–0.2 for Fmin(D) (the minimal energy density threshold causing damage) and m = 0.06–0.5 for Fmix(ND) (the maximum energy density threshold for which no damage is observed). This is in contrast to the previously established scaling laws of d−1 or d−2. The results are discussed in terms of defect density, which was checked for a number of samples with distribution plots taken from optical micrographs of undestroyed portions of the coating.

Round-robin results on the determination of hydrogen in tantalum and niobium

The effects of hydrogen on the physical and especially the mechanical properties of metals are summarized. Currently available methods for hydrogen analysis in metals are briefly discussed. The results of round-robin tests on the total hydrogen content of tantalum and niobium sheet materials are presented. The hydrogen contents of both materials were found to be below 1μg/g, i.e. near to the detection limits. Vacuum and carrier-gas fusion and diffusion extraction methods were used for analysis. It was found that etching is the best means of sample preparation for determination of hydrogen in tantalum and niobium.

Results of Galvanic Corrosion Round Robin Testing

Results of Galvanic Corrosion Round Robin Testing