  We have previously used an array of cryogenic microcalorimeters with 4 eV
energy resolution to measure emission-line profiles and energies of the
characteristic L-shell x rays of four elements of the lanthanide series:
praseodymium, neodymium, terbium, and holmium. We consider the power of the
same data set for the estimation of the lines' relative intensities.
Intensities must be corrected for detector efficiency and self-absorption, and
we estimate uncertainties on the corrections. These data represent one of the
first uses of cryogenic energy-dispersive sensors to estimate the relative
intensities of x-ray fluorescence lines. They show that a future measurement of
thin-film samples with microcalorimeter detectors could achieve systematic
uncertainties below 1% on relative line intensities over a broad energy range.
