He jets, β-recoils, and a search for super-heavy hor-ellipsis Molecular ions

The evolution of ones research activities over the years is often a consequence of surprises and unexpected observations. Such is the case with the development of the helium jet recoil transport method in the early 1960s and what has followed since then. The use of seeded beams and supersonic jet nozzle/skimmer techniques to the He jet technology in the 1970s was directed to the development of β-recoil mass spectrometry for short-lived nuclides based on surface ionization in vacuum of monolayers of nuclear reaction products. An unexpected spin-off of these studies, was the solution of a long-standing problem in biomedical mass spectrometry - how to produce gas phase molecular ions of species that are involatile and thermally unstable. The fundamental observation was that ionizing radiation with a high LET can induce desorption and ionization of complex molecular species. This formed the basis of a mass spectrometry using 252-Cf fission fragments as an ion source. The technique is being used in biomedical research laboratories throughout the world. At the same time, experiment and theoretical programs have been initiated to deduce the mechanism of the desorption/ionization process and elements of the temporal properties of the nascent fission track