The University of Cambridge Radiocarbon Dating Laboratory has been completely rebuilt and modernized, incorporating new techniques developed here for the various stages of measurements. Sample radioactivity is measured in gas proportional counters after conversion to highly purified CO2. Four counters are mounted within a single anticoincidence shield consisting of plastic scintillation material. This is surrounded by a graded cosmic ray shield of low radioactive steel, boron loaded wax, and finally, about 16 tons of ancient low radioactive lead blocks. The electronics are all solid state devices except for the stabilized high voltage supplies.
University of Cambridge Natural Radiocarbon Measurements IX