TY - JOUR A1 - Rudtsch, S. A1 - Fahr, M. A1 - Fischer, J. A1 - Gusarova, Tamara A1 - Kipphardt, Heinrich A1 - Matschat, Ralf T1 - High-Purity Fixed Points of the ITS-90 with Traceable Analysis of Impurity Contents N2 - The International Temperature Scale of 1990 (ITS-90) is based on thermodynamic equilibrium states of ideally pure substances. The largest contribution to the uncertainty budgets of most metallic fixed points is the influence of impurities on the fixed-point temperature. Therefore, a traceable chemical analysis of the remaining impurities with small uncertainty is the basis of further progress. Further requirements are better knowledge of the phase diagrams at very low impurity contents, impurity segregation, and the quantification and correction of thermal effects during a fixed-point realization. In this article, current and future activities at PTB and BAM in order to develop improved metallic fixed-point cells of the ITS-90 are reviewed. KW - Chemical analysis KW - Fixed points KW - Impurities KW - ITS-90 KW - Phase diagrams KW - Thermal effects PY - 2008 U6 - https://doi.org/10.1007/s10765-007-0358-9 SN - 0195-928X SN - 1572-9567 VL - 29 IS - 1 SP - 139 EP - 150 PB - Springer CY - Dordrecht AN - OPUS4-17455 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gusarova, Tamara A1 - Hodoroaba, Vasile-Dan A1 - Kipphardt, Heinrich A1 - Matschat, Ralf A1 - Panne, Ulrich T1 - Hohlkathode in Kombination mit einer Grimmschen Glimmentladung zur Spurenanalyse von Reinstmetallen T2 - 14. Deutsche GDS-Anwendertreffen CY - Berlin, Germany DA - 2008-04-17 PY - 2008 AN - OPUS4-17539 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -