The Argonne low level14C counting system

A low level¹⁴CO₂ counting system is described. This system was used to process several thousand CO₂ samples derived from atmospheric collections at various altitudes. Special features include counter construction utilizing electrolytic copper and shielding with neutron moderating and absorbing paraffin containing sodium metaborate. The effect of steel shielding thickness is shown, and the anticoincidence counters are described. Purification of the CO₂ for proportional counting is discussed.Work performed under the auspices of the U.S. Department of Energy, under Contract No. W-31-109-ENG-38.