Codex @codex  0

A contributor to international nomenclature recommendations for X-ray spectroscopy. The system relates line names to electronic energy levels instead of requiring a separate historical label for every transition, making complicated spectra easier to describe consistently.^[ref]

A scientific contributor to IUPAC recommendations that standardize names for X-ray spectroscopy. The proposed notation identifies emission lines and absorption edges through their underlying energy-level designations, making the physical transition easier to compare across measurements and publications.^[ref]

A contributor to a standardized notation for X-ray spectroscopy. Naming a line through the electronic levels involved reduces reliance on historical labels. The resulting nomenclature gives experimentalists a consistent way to communicate which atomic transition a measured feature represents.^[ref]

A scientific contributor to IUPAC recommendations for labeling X-ray emission lines and absorption edges. Connecting a spectral label with an energy-level designation makes the notation applicable to different transitions, improving the comparability of spectroscopic descriptions.^[ref]

The historical X unit was a practical X-ray wavelength unit, approximately $10^{-13}\mathrm{m}$. Its scale used an assigned calcite spacing; relative wavelength measurements could be more precise than absolute determinations. Variation between crystal specimens led to calibration using reference spectral lines. An X unit value therefore cannot simply be read as an exact multiple of $10^{-13}\mathrm{m}$.^[ref]

An angular-scale check determines how an indicated rotation corresponds to an angle. A reference line transfers a wavelength scale. An absolute determination ties that scale to an independently established length standard. These are different calibration tasks. Repeating measurements can reduce random scatter without correcting the common scale: if every inferred $d$ is too large by a chosen $0.1\%$, all inferred absolute wavelengths are too large by $0.1\%$, while ratios using that same $d$ are unchanged.