Resonance ionization mass spectroscopy for trace analysis of neptunium

Resonance ionization mass spectroscopic (RIMS) measurements for trace analysis and spectroscopy of 237Np, the ecologically most important isotope of neptunium, are described. The chemical procedure for the separation of neptunium from aqueous samples as well as the preparation of filaments for RIMS are outlined. Several two- and three-step excitation schemes have been investigated in order to find suitable conditions for the sensitive detection of 237Np. Using a three-step, three-color excitation and ionization scheme an overall detection efficiency of 3×10−8 was obtained, resulting in a detection limit of 4×108 atoms (160 fg) of 237Np. The hyperfine structure splittings of the levels under…

Erste Messung der Ionisationsenergie von Americium und Curium

Electrolytic preparation of actinide filaments for laser resonance ionization spectroscopy

Abstract For the determination of trace amounts of actinide elements by resonance ionization mass spectroscopy, atomic beams of these elements are produced by evaporation from rhenium substrates. The actinides are deposited by electrolysis as hydroxides in a 2 mm spot on a rhenium foil and covered electrolytically with a thin layer of rhenium or platinum. During heating of such a sandwich reduction occurs to the metallic state while diffusing through the overplated layers and the actinides are evaporated as atoms from the surface. With lead-doped platinum, efficient release is observed already at 1700°C in contrast to rhenium where 2100°C is required and a higher background is produced.

First Determination of the Ionization Potential of Americium and Curium