ASTM C1221-92(1998)

1.1 This test method is applicable to the determination of the concentration of gamma-ray emitting special nuclear materials dissolved in homogeneous solutions. The test method corrects for gamma-ray attenuation by the sample and its container by measurement of the transmission of a beam of gamma rays from an external source (Refs. (1), (2), and (3)).

1.2 Two sample geometries, slab and cylinder, are considered. The sample container that determines the geometry may be either a removable or a fixed geometry container. This test method is limited to sample containers having walls or a top and bottom of equal transmission through which the gamma rays from the external transmission correction source must pass.

1.3 This test method is typically applied to radionuclide concentrations ranging from a few mg/L to several hundred g/L. The assay range will be a function of the specific activity of the nuclide of interest, the physical characteristics of the sample container, counting equipment considerations, assay gamma-ray energies, sample matrix, gamma-ray branching ratios, and interferences.

1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazards, see Section 8.