#### Document Type

Report

#### Publication Date

2-1964

#### Abstract

Internal conversion coefficients were measured by observing with a well-type Nal(Tl) crystal the photon spectra emitted during the de-excitation from the first excited state to the ground state of Gd^{l54},D)y ^{160}, Yb^{l70}, Yb^{l71} and Pr^{l41} following the respective beta decays of Eu^{l54}, Tb^{l60}, Tm^{170}, Tm^{l71} and Ce^{l41}. The results were obtained by analysis of either the singles spectra, or spectra obtained by coincidence-sum techniques, or both. For the coincidence work gating was done either with high energy gamma rays or with beta particles. The spectra from the Yb isotopes were analyzed on a computer using a least-squares curve-fitting program. The photon detection efficiencies, necessary for the measurements, were calculated with a computer by performing numerical integrations. The following K-shell internal conversion coefficients were measured directly for first excited state to ground state transitions: 0.632 ± 0.016, for Gd^{l54}; 1.48 ± 0.05, for Yb^{l70}; 6.9:1: 1.0, for Yb^{l71} and 0. 375 ± 0. 009, for Pr^{l41}. The total internal conversion coefficients were measured for the first excited state to ground state transitions in Gd^{l54} and nyl60 and found to be 1. 20 ± 0. 02 and 4. 52± 0. 11, which yield respective K-shell internal conversion coefficients of 0. 637 ± 0. 016 and 1. 54± 0. 06 when multiplied by K to total ratios. The results for these 2+->0+ transitions in Gd^{l54} and Dy^{l60} and for this -t -forbidden Ml transition in Pr^{l41} are in good agreement with theory. The ratio of the experimental result to the theoretical value is 1. 09 ± 0. 06 for this 2+-0+ transition in Yb^{l 70}. The result for this Ml + E2 transition in Yb^{l71} implies a mixing ratio of E2/Ml = 0. 45 :±. 0. 09, assuming the theoretical internal conversion coefficients are correct.

#### Report Number

IS-1032

#### Language

en

#### File Format

application/pdf

#### Recommended Citation

Dingus, Ronald S.; Talbert, W. L. Jr.; and Hatch, E. N., "Measurements of some internal conversion coefficients using scintillation counter, coincidence techniques" (1964). *Ames Laboratory Technical Reports*. 85.

http://lib.dr.iastate.edu/ameslab_isreports/85