Direct measurement of alpha emission probabilities in the decay of $^{226}$Ra
Résumé
High-resolution alpha-particle spectrometry was performed to determine the main alpha-particle emission probabilities in the decay of $^{226}$Ra. Thin, homogeneous sources were prepared by electrodeposition on stainless steel disks. Alpha spectra with an energy resolution of 20 keV were obtained in three laboratories and analysed with different deconvolution algorithms. In two set-ups, a magnet system was used to deflect conversion electrons to avoid their coincidental detection with the alpha particles. Spectra taken at close range without a magnet system yielded biased results which cannot be fully compensated by statistical corrections for coincidence summing. The derived emission probabilities of the three main alpha decays are 94.07 (1)%, 5.93 (1)%, and 0.0059 (15)%, respectively. They are in excellent agreement with calculated values derived from the P(γ+ce) decay scheme balance, which solves the existing discrepancy problem with two previous direct measurements published in literature.
Mots clés
radioactivity
ionizing radiation
Alpha spectrometry
$^{226}$Ra
Decay data measurement
Alpha-particle emission probabilities
alpha-rays
spectrometry
alpha spectrometry
electrodeposition
radioactive source
spectrum analysis
alpha spectrum
source preparation
signal processing
deconvolution algorithm
conversion electron
deflection
coincidental detection
emission probabilities
interlaboratory comparison
Origine : Publication financée par une institution