Precise measurement of αK for the M4 transition from Irm193: A test of internal-conversion theory Academic Article uri icon


  • The 10.5-day isomer in 193Ir decays by a single 80.2-keV M4 transition directly to the ground state of that nucleus. We have measured the total intensity of K x rays relative to 80.2-keV γ rays for this transition to be 98.7(6). With the K-shell fluorescent yield for iridium taken to be 0.958(4), this result yields αK= 103.0(8) for the K-shell internal conversion coefficient (ICC). The calculated αK for this transition is particularly sensitive to the treatment of the hole that is created by conversion in the atomic K shell. Recent ICC tables, which ignore the hole, yield αK=92.0. We demonstrate that calculations incorporating the hole produce values between 99.6 and 103.3 depending on the approximation used. Our result strongly supports the need to include the hole.

author list (cited authors)

  • Nica, N., Hardy, J. C., Iacob, V. E., Raman, S., Nestor, C. W., & Trzhaskovskaya, M. B.

citation count

  • 27

publication date

  • November 2004