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Directional correlation measurements have been performed with two Ge(Li) counters on several γ rays in coincidence with the 121.78 and 334.31 keV γ transitions which de-excite the first 2+ levels in 152Sm and 152Gd, respectively. A total of 20 γ−γ directional correlations, 13 in the 152Sm nucleus and 7 in the 152Gd nucleus, was measured simultaneously. Several of the γ−γ directional correlations involved gamma transitions of weak intensity, for example the (688.66−121.78), (1457.4−121.78), and (1528.16−121.78) keV cascades in 152Sm and the (586.29−334.31) and (1089.73−334.31) keV cascades in 152Gd. Among the various results which could be extracted from these measurements, the most interesting appears to be the determination of a nearly pure E2 character for the 688.66, 964.01, 1112.04, and 867.33 keV gamma transitions. The first two γ rays de-excite the 2+ β- and γ-vibrational levels to the 2+ ground-state rotational level at 121.78 keV in 152Sm, whereas the last two γ rays de-excite the3+ γ-vibrational level to the 2+ and 4+ (at 366.44 keV) ground-state rotational levels in 152Sm.

The y rays emitted in the decay of the '52Eum,E isomeric pair have been studied with the use of highefficiency, high-resolution, solid-state detectors. These measurements together with Ge(Li)-Ge(Li) coincidence experiments revealed the existence of several new gamma transitions never previously reported. In all, 93 and 30 y rays were observed in the decay of 15'EuE and '52Eum, respectively. Calculations of the (3-and y-band mixing into the ground-state rotational band and into each other were carried out. These calculations showed that this mixing is insufficient in explaining the B(E2) ratios from the members of both the (3 and y band. In addition, the very likely existence of a K" = 2-band in 15'Sm, with levels at 1649.90 (2-) and 1757.0 keV (3-), has been unveiled in these measurements. Furthermore, the existence of a new K n = 0-octupole rotational band (levels at 1680.58 (I-) and 1730.3 (3-)) built on the B-vibrational band and the presence of a collective K n = 2 + vibrational state at 1769.1 keV, which most probably can be described as a coupled (By) two phonon state, are also proposed. Moreover, a new level at 1292.75 keV has been established through coincidence experiments in 15'Sm. This level may be considered either as the 2 + member of a second B-vibrational band or, more likely, can be described as a truly spherical state in light of recent experiments involving (t,p) and (p,t) transfer reactions to levels of 15'Sm. Finally, a qualitative analysis of the level structure of 15'Gd, as well as 150Sm, seems to show that these two nuclei display a more rotational nature than a spherical (or vibrational) one as previously suggested. Les rayons y Cmis lors de la dCsintCgration de la paire d'isom&res 15'Eum p g ont CtC CtudiCs en utilisant des detecteurs solides de grande efficacitk et haute rCsolution. Ces mesures et des expkriences de coincidence Ge(Li)-Ge(Li) ont rCvClC I'existence de plusieurs transitions gamma que personne n'avait encore signalkes. En tout, on a observC 93 transitions y dans la desintkgration de 15'Eug, et 30 pour 15'Eum. On a effectue des calculs sur le mClange des bandes (3 et y, I'une avec I'autre et avec la bande de rotation du niveau fondamental. Ces calculs montrent que ce mClange ne suffit pas a expliquer les rapports B(E2) observCs pour les membres des bandes (3 et y. Ces mesures ont de plus dCvoilC I'existence trCs probable d'une bande K" = 2-dans 15'Sm, avec des niveaux a 1649.90 (2-) et 1757.0 (3-) keV. On propose aussi I'existence d'une nouvelle bande octupolaire de rotation (niveaux ? i 1680.58 (1 -) et 1730.3 (3-)), batie sur la bande de vibration, ainsi que la presence d'un Ctat collectif de vibration K" = 2 + a 1769.1 keV, Ctat qui peut tres probablement Ctre dCcrit comme un Ctat couplC (By) a deux phonons. E n outre, les mesures de coincidences pour l5'Srn Ctablissent I'existence d'un nouveau niveau a 1292.75 keV. Ce niveau pourrait ou bien Ctre considCrC comme un membre 2+ d'une seconde bande de vibration (3 ou bien, plus vraisemblablement, Ctre dCcrit comme un Ctat vr...

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The y-ray spectra resulting from the decay of the 9 4 T~m . s isomeric pair to the excited states of 94Mo have been investigated using Ge(Li) solid state detectors. Gamma rays (relative intensities are in parentheses) of 871.05 (100); 993.19(2.35); 1 196.4(0.80); 1522.1 (4.80): 1868.68(6.10); 2393.2(0.50); 2529.8(0.33); 2740.1r3.74): 3129.1r1.47): 3512.5(0.06): 3793.1(0.05): 3892.7(0.016): plus several other weak lines have been observed in the decav of "~~" ( 5 2 nlin). Gamma rays (relathe-intensities are in ~arentheses) of .3(0.68);1592.1(2.25); 1765.6(0.29) have been detected in the decay of 94Tc"5 h). To investigate this latter activity a hollow coaxial Ge(Li) spectrometer was aiso used as a well-type detector in order to obtain sum spectra of coincident gamma rays. The overall results obtained from this study allows construction of a level scheme of "Mo which compares fairly well with previous investigations and removes some inconsistencies shown in Coulomb excitation measurements.

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The γ-ray spectra accompanying the decay of 96gTc (4.3 d) and 96mTc (52 m), produced in the reactions 96Mo (p, n) 96Tc and 97Mo (p, 2n) 96Tc, have been studied with lithium-drifted Ge detectors.Gamma rays (relative intensities are in parentheses) of 314.2 ± 0.2 (2.4), 316.3 ± 0.2 (1.5), 434.8 ± 0.4 (0.8), 460.2 ± 0.4 (0.48), 568.9 ± 0.4 (.95), 778.2 ± 0.2 (100), 812.5 ± 0.2 (83), 849.8 ± 0.2 (98), 1091.3 ± 0.4(0.9), 1126.8 ± 0.3 (15.3), 1200.0 ± 0.4 (0.41), and 1497.7 ± 0.5 keV (0.081), plus several other very weak lines, have been observed in the decay of 96Tc (4.3 d). Several transitions never previously reported were found in the decay of 96mTc (52 m). All but four of these transitions could fit already known excited levels in 96Mo at 778.2, 1497.9, 1628.0, 1869.6, and 1978.3 keV, whereas the placing of the remaining 616.1-, 966.6-, 1096.6-, and 1816.2-keV gamma rays required the existence of a new level in 96Mo at 2594.5 keV.In view of the results obtained from the study of the decay of the 96Tc isomeric pair, it was considered very desirable to reinvestigate the decay of 96Nb to levels in 96Mo. The 96Nb source was produced in the reaction 96Zr (p, n) 96Nb. Ge(Li) detectors were again employed and gamma–gamma directional correlation measurements were performed with two NaI(Tl) crystals, a fast coincidence circuit, and a multiparameter analyzer to record the data.The experimental directional correlation coefficients of the 1200.1–778.2, 1200.1–460.1, 778.2–460.1, 1091.4–778.2, 1091.4–568.7, and 778.2–568.7 keV cascades are[Formula: see text]respectively.These values seem to be compatible with spin assignments of 4+, 3+, and 5+ for the 1869.6-, 1978.3-, and 2438.4-keV levels in 96Mo respectively.