KX-Ray Yields of PrimaryCf252Fission Products

Abstract

The yields of $K$ x rays emitted by primary ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ fission products have been measured with a high-resolution [0.82 keV full width at half-maximum (FWHM) at 26.25 keV] lithium-drifted silicon spectrometer. The most noteworthy feature in the systematics of the observed x-ray yields is the presence of a pronounced even-odd fluctuation associated with the atomic numbers $Z=52\mathrm{}$ through $Z=57\mathrm{}$, in which the odd-$Z$-product x rays are found to be more intense than the even-$Z$-product x rays by approximately a factor of 2. This effect is not observed in the light-fission-product region. The x-ray yields observed in this experiment are compared with the results of previous experiments in which the $K$ x-ray yields were measured in association with the fission-fragment masses. Although general agreement is found in the over-all structural features, no evidence is seen in this study of the sudden drop in x-ray yield in the heavy-fission-product region corresponding to that which has previously been reported. The validity of the use of x-ray measurements as a method of determining the most probable charge distribution is examined in the light of the observed structure in the systematics of the x-ray yields.