Precise measurement of K-shell fluorescence yield in iridium: An improved test of internal-conversion theory Academic Article uri icon


  • We have measured the total intensity of K x rays relative to 129.4-keV γ rays from decay of the second excited state in Ir191. This (M1+E2) transition was observed following the β decay of 15.4-d Os191. Our measured ratio yields the result αKωK=2.044(11). When combined with a recent measurement of the same ratio for the 80.2-keV M4 transition from Ir193m, this result strongly confirms the need for the K-shell hole to be included in calculations of internal-conversion coefficients αK. Since the αK value calculated for the Ir191 transition is virtually independent of the hole treatment, our result also yields a model-independent value for the iridium fluorescence yield, ωK=0.954(9). © 2005 The American Physical Society.

author list (cited authors)

  • Nica, N., Hardy, J. C., Iacob, V. E., Montague, J. R., & Trzhaskovskaya, M. B.

citation count

  • 19

publication date

  • May 2005