Liquid Scintillation Alpha Spectrometry Techniques

Alpha spectrometry using liquid scintillation methods has matured into a technology showing great potential. The nonpenetrating properties shared by beta and alpha radiation make them both candidates for liquid scintillation counting/spectrometry. However, applying liquid scintilla-tion to alpha spectrometry has been difficult, because inefficient light production by alpha particles led to poor alpha energy resolution and alpha-produced scintillation interference of beta- and gamma-produced scintillations. Recent developments in alpha liquid scintillation spectrometers and pulse-shape discrimination have removed the beta-gamma interference problem and greatly improved alpha energy resolution. In addition, selective solvent (liquid-liquid) extraction methods (phase-transfers), setting the nuclide of interest into the scintillator, simplifies sample preparation and provides important additional information for nuclide identifi-cation. Such rapid, selective procedures have been developed for radium, uranium, thorium, plutonium, polonium, and the trivalent transplutonium elements. Presently, available energy resolution (230 keV FWHM) allows identification of many of the isotopes of these nuclides. Chemical separations methods and typical alpha-spectral results are presented in this chapter. Promising methods of improving both energy resolution and chemical separations are suggested