G. L. Struble

Magnetic properties of odd-odd deformed nuclei

Abstract Magnetic moments and Ml transition probabilities depend on the parameters g R , g Ω p , and g Ω n in odd-odd deformed nuclei. The parameter gR can be obtained from an intraband branching ratio and a magnetic moment. Available data are analyzed and compared with predictions of the unified model.

The 154Eu(t, p) reaction: Some new systematics in the N = 90 spherical-deformed transition region

A radioactive target of 154Eu(8.3y) has been used to study the 154Eu(t, p)156Eu reaction at an incident energy of 17 MeV. The bandhead and one rotational state of the {;π52[413]; ν112[505]}K = 3− configuration have been identified in 156Eu. The excitation energy of the 3− bandhead is determined to be 448 ± 15 keV. The angular distribution of the first excited rotational state is anamolous and may indicate evidence for a strong two-step component in the reaction mechanism. The energy systematics of the Eu-Sm transition region are also investigated. We find that the systematics of h22I suggest that at N = 87 the 150Eu {π52[413]; ν112[505]}K = 3− excited configurations has a significantly more stable deformed structure than the corresponding 112[505] one-quasiparticle structure in 149Sm.

The 152,154Eu(t, α) reactions: Studies of the 112[505] bands in 151Sm and 153Sm☆☆☆

Radioactive targets of 152Eu(13 y) and 154Eu(8.5 y) have been used to study the 152,154 Eu(t, α)151,153Sm reactions at an incident triton energy of 16 MeV. In these studies, we have identified the bandhead and three excited rotational states of the 112[505] neutron orbital in both the 151,153Sm nuclei The angular distributions and relative intensities for states in this band in both 151,153Sm are reproduced reasonably well by using DWBA calculations and by assuming strongly deformed single-particle wave functions. We have used our results and the results of other studies to determine the equilibrium prolate shapes of both 151,153Sm when the odd-neutron quasiparticle occupies the 112[505] orbital. We estimate β2 ~ 0.26 for 151Sm and β2~ 0.3 for 153Sm.

Search for stable octupole deformation in 225Fr

Abstract Levels in 225 Fr have been studied by γ-ray and conversion-electron spectroscopy following the β-decay of 225 Rn, and by the 226 Ra(t,α) 225 Fr single-proton-pickup reaction. Multipolarities were obtained for ∼50 γ-transitions, and a level scheme was established in which definite spin-parity values were determined for over 20 of the 48 levels. Although low-lying rotational bands of both parities exist for K = 1 2 and K = 3 2 , there is no experimental evidence to claim these are parity doublets. E1 strengths connecting the K π = 3 2 ± bands are intermediate between those for nuclides which are reflection symmetric and those claimed to be octupole deformed. The (t,α) cross sections are in better agreement with those predicted for the reflection-symmetric case than with those from an octupole-deformed description. These observations may be confirming theoretical predictions that octupole correlations are important in 225 Fr, but that there is no large stable octupole deformation.

In-beam study of174Lu isomers

Levels in174Lu have been investigated using the176Yb(p,3n) reaction. Prompt and delayedγ-ray spectra have been observed with a 0.56-cm3 Ge(Li) detector by a multispectrum analysis method. The half-life and decay mode of two isomeric levels, one at 240.8keV (395±15ns) and the other at 365.1keV (145±3ns) have been firmly established. Hindrance factors are discussed. New delayed transitions in175Lu are also noted.

GAMMA AND OCTUPOLE VIBRATIONS IN DEFORMED NUCLEI

Abstract The gamma (2 + ) and octupole (0 − , 2 − ) states of deformed even nuclei in the rareearth region are calculated in the Fermi liquid theory. The relation of RPA and schematic model calculations to the more general formulation is discussed. Off-diagonal matrix elements are found to peak at the nuclear surface. The vibration modes studied are found to be only weakly dependent on the spin- and isospin-dependent terms in the interaction. An example is presented to show the necessity for including a long-ranged term in the renormalized interaction.

Electromagnetic decay of 10+ states and yrast isomers in 208Pb

Abstract Gamma decay of the four previously known 10 + states between 4.8 and 5.9 MeV of excitation in 208 Pb, and isomerism of the lowest 10 + [T 1 2 =500(50) ns ] and 8 + [T 1 2 =3.2(5) ns ] states have been established with α - γ coincidence measurements in 209 Bi(t, αγ ) 208 Pb. Wavefunctions for the 10 + states were deduced in the model space involving 1p-1h excitations only. These show that the π h 9 2 h 11 2 −1 strength is nearly evenly distributed among the 10 + states, in disagreement with results from (e, e′) data.

Evidence for a strongly deformed prolate shape at N = 87 from 154Eu and 152Eu(p, t) reactions

Abstract The (p, t) reaction on radioactive targets of 152,154Eu has been used to study rotational states associated with the { p 5 2 [413]; n 11 2 [505]} K=3 − configuration in the transitional odd-odd 152Eu and 150Eu nuclei. Our studies yieldcompelling evidence that this configuration in 150Eu has a prolate structure which is strongly deformed and occurs at excitation energy of 1224 keV.

Quadrupole moments of low-energy isomers in 210Po

Abstract The quadrupole interaction frequencies of the 8 + , 11 − , 13 − and 16 + isomers in 210 Po have been measured in a Bi single crystal by the DPAD method with the 209 Bi(t, 2n) 210 Po reaction. The results for the quadrupole moments, normalized to Q (8 + 1 ) = −55.2 (20)fm 2 , are | Q (11 − )| = 86 (11)fm 2 , | Q (13−)| = 90(7)fm 2 and | Q (16 + )| = 129.7 (20) fm 2 . The quadrupole moment of the 0 i 13 2 proton orbital was deduced, and found to be surprisingly small. The results are compared with shell model calculations using the surface delta interaction as residual interaction.

The behavior of high-energy neutron pairing strength in the samarium isotopes

Abstract The (p, t) reaction has been used to study the behavior of two-neutron holes in the even Sm isotopes at high excitation energy. Both broad and narrow structures are observed at excitation energies above 5 MeV. Some of these can be interpreted in terms of the low-energy structure of 142 Sm.