Measurement of the energy and relative intensity of theKα1hypersatellite line inTm169

A measurement, carried out with a curved-crystal spectrometer, of the $K$ x rays of thulium emitted in the $K$ capture of ${}_{}{}^{169}{}_{}{}^{}\mathrm{Yb}$ has revealed the existence of a weak line which may be identified as the $K{\alpha }_1$ (Tm) hypersatellite line. The energy shift amounts to 1.04 ± 0.01 keV and the intensity of the hypersatellite line relative to the intensity of the $K{\alpha }_1$ (Tm) line is (7.6 ± 3.8) × ${10}^{-5\mathrm{}}$. The value of the energy shift agrees nicely with the shifts measured in other isotopes; the relative intensity is roughly in agreement with the value that may be expected on the basis of experimental data for other isotopes.