Alpha-particle Counting and Spectrometry in a Primary Standardisation Laboratory

This paper describes the application of alpha-particle counting at a defined low solid angle and of high-resolution alphaparticle spectrometry at IRMM. These techniques are used in the frame of primary standardisations of radioactive solutions or for the determination of nuclear decay data (alpha emission probabilities and energies, half-lives). Various technical aspects are discussed, such as source preparation, instrumentation, solid-angle calculations, peak shapes, fitting routines, bias of least-squares methods, off-line stability corrections, simulation of energy loss, uncertainties. The presented algorithms may also be useful for routine alpha-particle spectrometry, in particular for the assessment of its uncertainty budget.