GEL SUSPENSION COUNTING OF BARIUM CARBONATE-14C

Gel suspension counting of barium carbonate-14C using the channels ratio method of determining counting efficiency has been investigated. Determination of the specific activity of the material is not affected by variations in the particle size of the suspensions, unless large quantities of coarse material (up to 2-3 mm dia.) are counted, and self absorption is constant from sample to sample. The self absorption factor for barium carbonate-14C has been accurately measured. Gel suspension counting under the same conditions is shown to be unreliable for a crystalline material, D-glucose-14C(U), as large variations in self absorption occur with variations in particle size. © 1969.