Absolute energies and emission line shapes of the L x-ray transitions of lanthanide metals

We use an array of transition-edge sensors, cryogenic microcalorimeters with 4 eV energy resolution, to measure L x-ray emission-line profiles four elements the lanthanide series: praseodymium, neodymium, terbium, and holmium. The spectrometer also surveys numerous standards in order establish absolute-energy calibration traceable International System Units for range keV 10 keV. new results include emission line 97 lines, each expressed as a sum one or more Voigt functions; improved absolute uncertainty on 71 these lines relative existing reference data; median peak 0.24 eV, ten times better than prior work; 6 that lack any measured values tables. comprise nearly all most intense from under broad-band excitation. work improves previous measurements made similar by sensors linearity absorbed gold absorbing layer has Gaussian energy-response function. It employs novel sample holder enables rapid switching between science targets excellent gain balancing. Most shown here should be considered replacements currently tabulated standard values, while shapes given represent significant expansion scope available data.