Search for Si34 ions in Am241 decay

An experiment has been performed to measure the spontaneous fission branch of Am241 and to search for decay events by emission of Si34 nuclei. Lexan polycarbonate foils were used for the detection of decay fragments. Tracks produced in the foils by 81 MeV Si28 ions from an accelerator and fission fragments from a Cm248 source were compared with those produced by particles emitted from a 0.5 mCi Am241 source. We identified 33 fission fragments corresponding to a fission/alpha branching ratio of (2.40.5)×10-12, in fair agreement with previous measurements. No Si34 tracks were observed which results in an upper limit of 4.2×10-13 for the Si34/alpha ratio at the 90% confidence level. Two theoretical calculations predict values of 4.0×10-13 and 1.1×10-15 for this branching.