Measuring the absolute decay probability of Sr-82 by ion implantation

We have developed a method of implanted ion counting in order to determine the absolute decay probability of the 776.5 keV gamma-ray transition in the decay sequence of Sr-82 -> Rb-82 -> Kr-82. A 215 MeV beam of Sr-82 was produced at the Holifield Radioactive Ion Beam Facility and passed through an ionization chamber that counted and identified the ions before they were implanted into thin aluminum foils. Subsequent offline measurements using a Ge detector deduced the probability per decay of Rb-82 for the 776.5 keV gamma ray in Kr-82 to be 0.1493(37), in agreement with the accepted average value of 0.1508(16). This new technique measures directly the number of decaying nuclei in a given sample and significantly reduces the dependence on knowledge of the complete decay level scheme.