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

The americium 241 in solid plutonium materials may be determined when these materials are dissolved (see Practice C 1168).

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 C 758 and C 759).

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.

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

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

Solutions containing as little as 1 × 10 ⁻⁵ g/L americium 241 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.

1.1 This test method covers the quantitative determination of americium 241 by gamma-ray spectrometry in plutonium nitrate solution samples that do not contain significant amounts of radioactive fission products or other high specific activity gamma-ray emitters.

1.2 This test method can be used to determine the americium 241 in samples of plutonium metal, oxide and other solid forms, when the solid is appropriately sampled and dissolved.

1.3 This standard does not purport to address all of the safety concerns, 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.