MEASUREMENTS AND EVALUATION OF ABSOLUTE EMISSION PROBABILITIES FOR SOFT PHOTONS OF GD-153, EU-155 AND YB-169

Absolute emission probabilities of Kx- and gamma-rays in the energy re gion 40-200 keV have been obtained for Gd-153 and Eu-155 using measure ments of emission rates by Ge, Ge(Li) and Si(Li)-detectors and of acti vities by a 4 pi beta-gamma coincidence system. The main results of ou r measurements and evaluation of decay data of Gd-153 and Eu-155 were published in 1992 and 1994. Here new experimental data concerning soft photon radiation which were obtained with a new Si(Li) spectrometer c alibrated on the basis of a generalized energy response function are p resented. For the 14.06 keV gamma-ray in the decay of Gd-153 a value o f (01029 +/- 0.003) photons per 100 disintegrations has been measured. For Eu-155 the absolute emission probabilities of Kx- and 26.5, 45.3, 58.0, 60.0 gamma-rays have been measured using the Si(Li) (formerly o nly a Ge-detector was used). A re-evaluated value of the Gd-153 half-l ife is reported. For Yb-169 the evaluation of decay data has been carr ied out taking into account the results of the latest measurements of absolute emission probabilities of gamma-rays with energies 63.12, 109 .80, 130.52 and 197.96 keV.