Standard Test Method for Quantitative Determination of ²⁴¹Am in Plutonium by Gamma-Ray Spectrometry

5.1 This test method allows the determination of ²⁴¹Am in a plutonium solution without separation of the americium from the plutonium. It is generally applicable to any solution containing ²⁴¹Am.

5.2 The ²⁴¹Am in solid plutonium materials may be determined when these materials are dissolved (see Practice C1168).

5.3 When the plutonium solution contains unacceptable levels of fission products or other materials, this method may be used following a tri-n-octylphosphine oxide (TOPO) extraction, ion exchange or other similar separation techniques (see Test Methods C758 and C759).

5.4 This test method is less subject to interferences from plutonium than alpha counting since the energy of the gamma ray used for the analysis is better resolved from other gamma rays than the alpha particle energies used for alpha counting.

5.5 The minimal sample preparation reduces the amount of sample handling and exposure to the analyst.

5.6 This test method is applicable only to homogeneous solutions. This test method is not suitable for solutions containing solids.

5.7 Solutions containing as little as 1 × 10 ⁻⁵ g/L ²⁴¹Am may be analyzed using this method. The lower limit depends on the detector used and the counting geometry. Solutions containing high concentrations may be analyzed following an appropriate dilution.