Extension of the Carbon 14 Age Method

Abstract

The use of a 1-in. mercury shield around the screen wall counter inside the anticoincidence ring of cosmic-ray counters makes it possible to reduce the background from 5 cpm to 2 cpm for an active counting volume 8 in. in length and 2⅝-in. in diameter. This makes it possible to extend routine C14 age measurements from about 25,000 to 30,000 years.