An Atomic Beam Source for Actinide Elements: Concept and Realization

Abstract

Atomic beams /Actinide elements / Resonance ionization mass spectroscopy / Volatilization SunmiaryFor ultratrace analysis of actinide Clements and studies of their atomic propcrties with resonance ionization mass spectroscopy (RIMS), efficient and stable sources of actinide atomic beams are required. The thermodynamics and idnetics of the evaporation of actinide elements and oxides from a variety of metals were considered, including diffusion, desorption, and associative desorption. On this basis various sandwich-type filaments were studied. The most promising system was found to consist of tantalum as the backing material, an electrolytically deposited actinide hydroxide as the source of the element, and a titanium covering layer for its reduction to the metal. Such sandwich sources were experimentally proven to be well suited for the production of atomic beams of plutonium, curium, berkelium and califomium at relatively low operating temperatures and with high and reproducible yields.

Trace determination of gadolinium in biomedical samples by diode laser-based multi-step resonance ionization mass spectrometry

“…The results are summarized in Table 1 and show that only Ti foil yielded significant improvement, with efficiency increased 17-fold over direct loading. This behavior is consistent with similar improvements observed in the atomization of plutonium from tantalum filaments over-coated with Ti, which was explained theoretically with thermodynamic and kinetic arguments [35]. Corresponding calculations for Gd indicate that reduction at the surface and diffusion through the Ti foil achieves the same effective atomization rate at temperatures that are lowered by about 300-400°C as compared to direct loading (Eichler B, personal communication).…”

Plutonium measurements by accelerator mass spectrometry at LLNL

“…These are fission track analysis (FTA), 11,13,15,[22][23][24] thermal ionization mass spectrometry (TIMS), 4,5,7,14,25,26 inductively coupled plasma-mass spectrometry (ICP-MS), [27][28][29][30][31][32][33] 3 and resonance ionization mass spectrometry (RIMS). [34][35][36][37] All of these techniques have demonstrated sensitivities of 10 6 -10 8 atoms per sample, depending on the application and the level of interferences present, and all except FTA can provide 240 Pu/ 239 Pu isotopic ratios.…”

Fast chemical separations and laser mass spectrometry – tools for nuclear research

“…An atomic beam of the element to be investigated is obtained by resistive heating of a sandwich filament consisting of a thin tantalum backing on which the element is electrolytically deposited (3 mm spot) either after a chemical separation procedure or directly from a pure solution in form of its hydroxide and covered with a thin layer (∼ 1 μm) of titanium or zirconium by sputtering. By heating such a filament the hydroxide is converted to the oxide which is reduced to the metallic state during the diffusion through the covering layer [65]. Efficient release of atoms from the sandwich filaments occurs at temperatures between 800 and 1200…”