• Second Announcement

      Department of Geosciences, The University of Arizona, 1990-01-01
    • Sources of Random Error in the Debrecen Radiocarbon Laboratory

      Hertelendi, Ede (Department of Geosciences, The University of Arizona, 1990-01-01)
      A new high-pressure methane-filled counter system for 14C dating was installed in 1986 when the first stage of the International Collaborative Study (ICS) started. Random errors in the new measuring system and in the process of chemical pretreatment and preparation were checked during the three years of intercomparison. Results show that the most important source of error in our laboratory is gas contamination. This causes variation of the count rate to exceed the statistically expected variability. Other sources of error are also discussed and limits of their contributions are given.
    • Statistical Quality Control Graphs in Radiocarbon Dating

      Switsur, Roy (Department of Geosciences, The University of Arizona, 1990-01-01)
      I describe here the establishment and use of statistical control graphs based on the analysis of variance for monitoring the stability of operation of radiocarbon dating counting systems.
    • Systematic Biases in Results of the International Collaborative Study and Their Probable Sources

      Pazdur, Mieczysław F.; Awsiuk, Romuald; Goslar, Tomasz; Pazdur, Anna (Department of Geosciences, The University of Arizona, 1990-01-01)
      Results of the International Collaborative Study show an unexpectedly large scatter of individual dates as well as systematic biases. Very high values of linear correlation coefficients are observed for all results of Stage 2 and for benzene samples of Stage 1. We observed moderate correlations for carbonate samples and the lowest for natural samples of wood and peat of Stage 3. The correlation is practically negligible among results obtained in different stages. The probable reasons for such effects are seen in medium-term changes in the calibration of the counting systems.
    • Tentative Conference Sessions

      Department of Geosciences, The University of Arizona, 1990-01-01
    • Time-Resolved Liquid Scintillation Counting

      Kessler, Michael (Department of Geosciences, The University of Arizona, 1990-01-01)
      Historically, scientists who perform low-level measurements of 14C for age dating, and 3H2O for environmental contamination, have purchased or constructed highly specialized instruments to quantitate low-level radionuclides using a general-purpose liquid-scintillation analyzer (LSA). The LSA uses special time-resolved 3-D spectrum analysis (TR-LSC) to reduce background without substantially affecting sample counting efficiency. This technique, in combination with a special slow fluor scintillating plastic, further reduces the minimal detectable limit for the TR-LSC liquid scintillation counter.