Berlin Radiocarbon Measurements II

This date list covers age measurements carried out at the Radiocarbon Dating Laboratory of the German Academy of Sciences of Berlin (DAW) since 1963 and is a continuation of our first date list (Berlin I). Procedures and methods of preparing the samples are essentially the same. We completed our laboratory with a second electronic counting apparatus. Two further proportional counters with internal anticoincidence (Houtermann-Oeschger counters) are made from an old railway-car axle. The total volume of these counters is 4 L, the effective volume 2.2 L, the background 2.0 counts/min at 700 Torr (acetylene filling), and the contemporary standard value (0.95 NBS oxalic acid) is 20 counts/min. Each sample is measured twice, first for 48 hr and after 8 days for another 24 hr. Data have been calculated on the basis of a C 14 half-life of 5570 yr (Godwin, 1962). Errors listed include the standard deviations (1σ) of the counting rates of the contemporary samples, the background and the unknown samples. Calculated errors less than 100 yr have been increased to that figure as a minimum. Corrections have not been made for C 13 content. Mass spectrometrics C 13 measurements of some samples indicate that errors resulting from fractionation are minimal.