The decay of141Ce

Abstract

The decay of ~Ce has been reinvestigated using different experimental methods. The efficiency extrapolation technique applied to 47c/?-y coincidence measurements has been employed for the determination of the disintegration rate of the sources and of the total internal conversion coefficient. The K X-ray and y-ray emisssion rates have been measured with a calibrated Si(Li) and an intrinsic germanium detector. Additionally the photon intensities have been determined from the internal conversion coefficients. Electron experiments with a magnetic/?-spectrometer yielded the relative intensities, the shape factors and the maximum energies of the two /?--transitions and the internal conversion ratios K/L and K/(L+M+...). The K-shell internal conversion probability has been determined with an electron K X-ray coincidence technique using the magnetic /?-spectrometer together with a high energy resolution Si(Li) detector. New values for the following decay properties have been deduced: /? -intensities (p~ =0.306 +0.006, p2=0.694_+0.006), shape factors C=const (I+A~) (A I = -(0.24 _+ 0.03), A2= -(0.22 + 0.04)), maximum/?--energies (E o 1 = (582.2 _+ 2.6) keV, Eo2 = (436.7 _+ 4.6) keV), Kshell internal conversion coefficient (c~=0.376+0.008), total internal conversion coefficient (e=0.438_+0.010), internal conversion ratios (K/L= 7.29 +_0.24, K/(L+M+...) = 5.78 _+ 0.18), y-ray intensity (I v = 0.482 + 0.003), K X-ray intensity (IKx = 0.168 + 0.002) and the photon intensity ratio (IKx/Iy=0.349+_O.O05). The procedure of uncertainty quotation is presented in some detail. The results are discussed with respect to existing experimental data.