Some recent experiments at ISOLDE

The Chalk River ISOL and ISOLDE are briefly described. Experiments detecting β-delayed protons from the decay of the T/sub z/ = -2 nucleus 32Ar and measuring the lifetimes of particle-unstable states in light electron-capture nuclei are sketched. Finally, a fictional nucleus (called pandemonium) was created, and its decay was simulated numerically by use of statistical principles. β-transition rates were known exactly, and an analysis of a simulated spectrum of β-delayed γ rays could be made. Transition rates could then be extracted from the simulated numerical data and compared with the known true rates. 14% of the γ intensity above 1.7 MeV was undetected in a peak analysis, and only about 35 out of 1000 gamma rays were identified. If the number of counts had been a factor of 10 less, 45% of the intensity would have been lost. Thus, every complex β-decay scheme that is based on γ-ray peak analysis and intensity balances must now be regarded as doubtful. If significant γ-ray intensity remains unobserved, the derived β-decay branching ratios could be wrong by orders of magnitude. 12 figures