Precise α_K and α_T Internal Conversion Coefficients Measurements of 39.752(6)-keV E3 Transition in ^103mRh: Test of Internal Conversion Theory

We used the γ- to x-ray ratio method to measure α_K and α_T for the 39.752(6)-keV E3 transition in ^103mRh, which we populated by both the β^- decay of ¹⁰³Ru and the ε decay of ¹⁰³Pd. Based on the particularities of the two level schemes, from ¹⁰³Ru decay one can extract both α_K and α_T, while the ¹⁰³Pd decay provides a relationship between α_K and α_T, which is useful as a consistency check. Sources of ¹⁰³Ru and ¹⁰³Pd were prepared by neutron activation, and measured for about four months. From ¹⁰³Ru decay we extracted α_K = 140.8(39) and α_T = 1428(29); then, using this value of α_K, we obtained α_T = 1438(37) from ¹⁰³Pd decay. All the results are preliminary. When compared with Dirac-Fock calculations, these results are in statistical agreement with the version of the theory that incorporates the effect of the K-shell atomic vacancy, α_K = 135.3(1) and α_T = 1404(1), and disagree with the version that does not, α_K = 127.5(0) and α = 1388(2). This is consistent with the results from the series of three E3 and six M4 transitions that we measured previously, and extends our measurements to the lowest Z we have studied so far.