CALIBRATION OF THE ISOMER SHIFT OF ¹²⁹I

Abstract

Radioactive 129mTe was implanted in 6 different transition metals (V, Fe, W, Au, Pt, Pb) and internal conversion electron spectra as well as Mössbauer spectra of the daughter nucleus 129I were measured. A value Δ = 0.018 (4) fm2 (corresponding to ΔR/R = + 4.1(10) x 10-4) was derived for the change of the mean square charge radius during the 27.8 keV transition in 129I. The consequences of this measurement for the calibration constants of the Mössbauer isomer shift of other isotopes of the 5sp-elements are discussed. A paper about this work is in progress of publication /1/