The Disputed Discovery of Element 43: A Reexamination of an Elegant Early Use of Wavelength-Dispersive X-Ray Microanalysis
J T. Armstrong, P H. Van Assche
In 1925, Noddack, Tacke and Berg reported discovery of element Z = 43, which they named Masurium, based on line identification of x-ray emission spectra from chemically concentrated residues of various U-rich minerals. Their results were disputed and eventually the discovery of element 43 (Technetium) was generally credited to Perrier and Segre, based on their chemical separation of neutron-irradiated molybdenum in 1937. Using first principles x-ray emission spectral generation algorithms from the NIST DTSA spectral processing program, we have simulated the x-ray spectra that would be expected using their likely analytical conditions (from Berg, 1925) and the likely residue compositions suggested by Noddack et al. (Van Assche, 1988). The resulting spectra are in close agreement with that reported by Noddack et al., place limits on the possible residue compositions, and are supportive of the presence of detectable element 43 in their sample.
Microscopy and Microanalysis
chemical elements, masurium, noddack, segre, spontaneous fission, technetium
and Van Assche, P.
The Disputed Discovery of Element 43: A Reexamination of an Elegant Early Use of Wavelength-Dispersive X-Ray Microanalysis, Microscopy and Microanalysis
(Accessed December 3, 2023)