Statistical theory of the adsorption of double molecules

Abstract
In order to compare the efficiency of different counting arrangements for radiocarbon dating the use of a factor of merit M = s$_{0}$/$\surd b$, where s$_{0}$ is the counting rate from a fresh carbon sample and b the background counting rate, is suggested. In standard low activity equipment with a Geiger or proportional counter surrounded by a ring of Geiger counters in anti-coincidence, the residual background is mainly due to the detection of secondary particles produced in the wall of the counter by uncharged radiations. A new type of proportional counter, in which this wall effect is reduced, is described. The counter is fitted with a ring of internal shielding counters separated only by a number of cathode wires from the main central counter. The operation of this counting equipment is discussed, and it is shown that the background of 2$\cdot $2 counts/min obtained under normal operating conditions in a sensitive volume of 5$\cdot $61, is due mainly to the absorption of uncharged radiations in the gaseous sample itself.

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