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3.4.3 Alpha and beta emitting radionuclides

Due to their properties, in-situ detection of alpha and beta emitters is very difficult and often only qualitative. In fact, very few portable detection systems exist for either of these types of emitters and they are often extremely radionuclide specific.

Laboratory sample preparation for alpha emitting radio-nuclides is similar to that for beta emitting radio-nuclides. Sample dissolution and purification tasks are also similar to those performed for beta emitting radionuclides.

Laboratory sample preparation is an important step in the analysis of surface soil and other solid samples for beta emitting radionuclides. The laboratory will typically have a sample preparation procedure that involves drying the sample and grinding the soil so that all of the particles are less than a specified size to provide a homogeneous sample. A small portion of the homogenized sample is usually all that is required for the individual analysis.
Once the sample has been prepared, a small portion is dissolved, fused, or leached to provide a clear solution containing the radionuclide of interest. The only way to ensure that the sample is solubilised is to completely dissolve the sample. However, this can be an expensive and time-consuming step in the analysis. In some cases, leaching with strong acids can consistently provide greater than 80% recovery of the radionuclide of interest and may be acceptable for certain applications. Gross beta measurements may be performed on material that has not been dissolved.