An improved Geiger-counter arrangement for determination of radium content.

Geiger-counter apparatus in which several counters may be placed in any position relative to each other is described. A circular arrangement of counters to give a counting rate approximately independent of the position of a so urce near the center of the circle is discussed. The relation of the I osition of the source to the counting rate of a single Geiger counter is discus ed. A method of calcul!J.tion of the self-absorption of a ample for the Geiger-counter a rrangement used is give n.