Alpha-particle emission probabilities of 236U obtained by alpha spectrometry

•Alpha-particle emission probabilities in the decay of 236U were measured.•High-resolution alpha-particle spectrometry on electrodeposited source was used.•Accuracy was improved by an order of magnitude.•Results are Pα,0=74.20 (5)%, Pα,1=25.68 (5)% and Pα,2=0.123 (5)%.

High-resolution alpha-particle spectrometry was performed with an ion-implanted silicon detector in vacuum on a homogeneously electrodeposited 236U source. The source was measured at different solid angles subtended by the detector, varying between 0.8% and 2.4% of 4π sr, to assess the influence of coincidental detection of alpha-particles and conversion electrons on the measured alpha-particle emission probabilities. Additional measurements were performed using a bending magnet to eliminate conversion electrons, the results of which coincide with normal measurements extrapolated to an infinitely small solid angle. The measured alpha emission probabilities for the three main peaks – 74.20 (5)%, 25.68 (5)% and 0.123 (5)%, respectively – are consistent with literature data, but their precision has been improved by at least one order of magnitude in this work.