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Using a quadrupole mass spectrometer system the permeation of D2, He, Ne, Ar, Kr and Xe through EPDM (ethylene-propylene-diene rubber), Viton (fluoro rubber) and Silicone-rubber was measured as a function of temperature. The results for O-ring samples were compared with those for slab geometry. From the measured permeation functions the diffusion coefficients, the permeation coefficients and the solubilities of the gases in the elastomer materials were evaluated using a nonlinear fitting algorithm. The variations of these data with temperature yield the activation energies for diffusion and permeation as well as the heat of solution. The results confirm that the transmission of noble gases and of deuterium through elastomer materials is merely a physical process because the activation energies are far below common values for processes involving chemical reactions. The solubilities correlate well with the boiling temperatures of the gases and with the well depth of the Lennard-Jones interaction potential between the gas atoms. The diffusion coefficients monotonically decrease and the activation energies monotonically increase with increasing molecular diameter of the gases.
A thin-layer reference material for surface and near-surface analytical methods was produced and certified. The surface density of the implanted Sb layer was determined by Rutherford backscattering spectrometry (RBS), instrumental neutron activation analysis (INAA), and inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) equipped with a multi-collector. The isotopic abundances of Sb (121Sb and 123Sb) were determined by multi-collector ICP-MS and INAA. ICP-IDMS measurements are discussed in detail in this paper. All methods produced values traceable to the SI and are accompanied by a complete uncertainty budget. The homogeneity of the material was measured with RBS. From these measurements the standard uncertainty due to possible inhomogeneities was estimated to be less than 0.78% for fractions of the area increments down to 0.75 mm2 in size. Excellent agreement between the results of the three different methods was found. For the surface density of implanted Sb atoms the unweighted mean value of the means of four data sets is 4.8121016 cm-2 with an expanded uncertainty (coverage factor k=2) of 0.0921016 cm-2. For the isotope amount ratio R (121Sb/123Sb) the unweighted mean value of the means of two data sets is 1.435 with an expanded uncertainty (coverage factor k=2) of 0.006.