W. R. Kane

Nuclear levels in152Eu

The transitional nucleus152Eu has been studied using the (n, e), (n, γ), (nres,γ), (n, γγ), (d, p), (d, t) and (p, d) reactions. The experiments have been performed at nine different laboratories. A model independent level scheme was established including 95 levels below 510 keV and nearly 900 transitions by combination of low energy transitions and reaction data. More than 20 additional levels result from gamma rays and/or charged particle reactions. The level scheme is interpreted in terms of the Nilsson model indicating that152Eu is a deformed nucleus. Seven rotational bands and Nilsson configurations are established. An additional 27 rotational bands are tentatively or speculatively assugned. Gallagher-Moszkowski splittings are discussed. The neutron binding energy was determined as 6305.2±0.5 keV. The energy of the 9.3 h 0− isomer is 45.599 keV. The lifetimes of four levels were measured.Nuclear Reactions151Eu(n,γ),En=thermal and resonance; measuredEγ,Iγ,Ec.e.,Ic.e.,γγ Coinc.,γγΔt coinc.;151Eu(d, p),E=12MeV and 14MeV;153Eu(d, t),E=12MeV;153Eu(p, d),E =18MeV; deduced level scheme of152Eu,J, π, T1/2,cc, Nilsson configurations. Magnetic electron spectrometer, curved crystal spectrometer, Ge(Li) and Si(Li) detectors, magnetic spectrographs. Enriched targets.

Levels in 154Eu populated by (n, γ) and (d, p) reactions

Abstract The structure of the doubly-odd nucleus 154 Eu was investigated using neutron capture and (d, p) reactions on 153 Eu. The low-energy γ-ray and conversion electron spectra from thermal neutron capture, as well as the γ-ray spectrum for primary energies up to 6.5 MeV, were measured with precision instruments at the Institut Laue-Langevin, Grenoble. The multipolarities were determined for most of the detected low-energy transitions. The (n res , γ high ) spectrum measurements with 2 keV, 2 eV and 3 eV neutrons were performed at Brookhaven National Laboratory for primary transitions leading to the 0–600 keV excitation energies. The 153 Eu(d, p) 154 Eu reaction was measured with the Q3D spectrograph at TU Munich. A level scheme below 600 keV excitation energy comprising 99 levels was deduced and the parities and most probable spin values were determined from the experimental data. The low-lying levels were interpreted as due to the two-particle Nilsson configurations, taking into account the proton orbits 5 2 + [413], 5 2 − [532], 3 2 + [411] , and the neutron orbits 11 2 − [505], 3 2 + [651], 3 2 − [521], 3 2 − [532], 5 2 + [642], 3 2 + [402], 5 2 − [523], 1 2 + [400], 1 2 − [530] . The 145.3 (± 0.3) keV level observed in the (d, p) reaction can be identified with the isomeric level with T 1 2 = 46 min . The neutron separation energy for 154 Eu was determined to be 6442.0 ± 0.3 keV.

Levels and γ-ray transitions in 190Os, a perturbed O(6) nucleus☆

Abstract Levels up to 2.5 MeV in 190 Os have been studied with the (n, γ) and (n, e − ) reactions at thermal and resonance energies. Transition multipolarities were deduced from the measured conversion coefficients and from L- and M-subshell ratios. Due to the nature of the (n, γ) reaction, the level scheme developed stresses low spin states and is complementary to those already existing based on the ( α , x n) reaction and on β-decay from high spin parent states. The level populations are shown to lead to a new use of population systematics to extract nuclear structure information. The remarkable decay characteristics of the excited 0 + states are also studied and explained as a natural consequence of the interacting boson approximation model of Arima and Iachello. The full set of positive purity levels below the pairing gap is interpreted in terms of this model, specifically, in terms of the transition from the O(6) limit characterizing 196 Pt toward the deformed symmetric rotor limit.

Level structure of 191Os: Coexisting oblate and prolate configurations

Abstract An extensive level scheme for the transitional nucleus 191 Os has been constructed on the basis of (n, γ), (n, e − ) and (d, t) reaction data. γ-rays following thermal capture and average resonance capture (ARC) were detected with pair spectrometers. Secondary γ-ray spectra were obtained with the GAMS bent crystal spectrometers. The high precision of the resultant energies was the critical factor in developing a level scheme on the basis of Ritz combinations. γγ coincidences were obtained from both primary and secondary transitions. Conversion electrons, detected with the BILL spectrometer, gave multipolarity information. The (d, t) reaction measured with a Q3D magnetic spectrometer gave additional information on the hole states in 191 Os. A discussion of the resulting level scheme briefly reviews the fragmentation of negative-parity strength but focuses mostly on a rare example of an anti-aligned decoupled set of coexisting positive-parity states. For these, triaxial particle-plus-rotor calculations are carried out. Reasonable agreement is obtained and the calculations also explain the unusually strong population in (n, γ) of this set of mostly medium spin states.

The level scheme of 134Cs

Abstract Low-lying states in 134 Cs have been investigated using the 133 Cs(n, γ) 134 Cs and 133 Cs(d, p) 134 Cs reactions with various spectroscopic techniques. Numerous excited states in 134 Cs have been established with energies up to 1267 keV. The experimental data on the lowest negative- and positive-parity states are in fair agrement with the calculations based on two quasiparticles coupled to a vibrator. For higher excited states the multiplets appear more mixed than predicted by the simple model.

Spins of Levels in Sm 148

The primary neutron-capture

Properties of low‐lying states in 134Cs

\ensuremath{\gamma}

Single particle and vibrational bands in 155Gd, 161Dy, and 163Dy

rays emitted in the decay of the 3.4-eV resonance in

Average resonance capture studies of Dy 1 6 2 , 1 6 4

^{147}\mathrm{Sm}

Nuclear structure of 161Dy studied with (n, γ), (d, p) and (d, t) reactions

have been studied with a Ge(Li) detector and the crystal diffraction neutron monochromator at the Brookhaven high-flux beam reactor. The results obtained complement the average resonance capture studies of Buss and Smither. The spins and parities of levels at 1453.6 and 1663.4 keV are shown to be 2+. The results also indicate previously unreported levels at (1648.6), 1970.9, and 2142.5 keV with spins 2, 3, or 4. The spin of the 3.4-eV resonance is confirmed to be 3-.