On the Level Structure of¹⁵⁴Gd

Abstract

A detailed study on the gamma decay of 154Eu to 154Gd nuclei has been carried out using different advanced gamma rays spectrometers such as high efficiency hyper pure germanium (HPGe) detector, (HPGe–HPGe) coincidence spectrometer and HPGe-4π(NaI (Tl)) anti-Compton array. The identified gamma ray transitions were placed in a proposed decay scheme. The energy levels of 154Gd are calculated using the IBA-1 model and compared to the available experimental data. The rotational behavior of 154Gd is discussed in terms of moment of inertia.

N=90region: The decay ofEu154toKulp1, Wood2, Krane3 et al. 2004Phys. Rev. C

“…A recent paper [16] also reported several new lines which we do not observe with the published intensities. Most of these lines can be attributed to ␥ − ␥ sum peaks.…”

“…Only studies of 154 Eu decay have reported ␥ rays associated with proposed levels in 154 Gd at 1136 [14,16,17], 1233 [14], 1510 [14,15,18], 1879 [14,15], and 1895 keV [14,15]. The 1387 keV ␥ ray is the strongest of the transitions associated with these levels, and (with the 1510.0 keV ␥ ray, the other transition which defines the 1510 keV level) should be visible in our singles spectrum.…”

“…Most of these lines can be attributed to ␥ − ␥ sum peaks. The stron-gest of these new lines that does not coincide with a known ␥ − ␥ coincidence sum peak is a 765.1 keV transition reported to feed the 4 + level at 371 keV with I ␥ = 0.463͑134͒ [16]; we set an upper limit on this transition of 0.0014 and suggest that this peak may have resulted from a coincidence sum of the 723 keV ␥-ray transition and a 40 keV K ␣ x ray in Gd due to internal conversion. Because of the high incidence of summing in the spectra presented in [16], we do not set upper limits on any of the peaks reported in this work with intensities less than that suggested for the 765.1 keV ␥ ray; nor do we set upper limits on peaks reported in this work known to have coincidence summing contributions.…”