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The nuclear electric quadrupole moment ( Q moment) of the neutron-rich nucleus 33Al ( I = 5/2 , T1/2 = 41 ms) has been measured by the $ \beta$ -ray detected nuclear quadrupole resonance ( $ \beta$ -NQR) method for the first time. The 33Al nucleus is considered to be on the border of the island of inversion within which a significant intrusion of the pf orbits occurs across the N = 20 shell gap and the intrusion causes an anomalous enhancement of the Q moment. Polarized 33Al nuclei were produced from 36S (77.5MeV/ u beams through the fragmentation process and separated by LISE fragment separator at GANIL. The 33Al nuclei were implanted into a Al2O3 single-crystal plate and the $ \beta$ -NQR spectrum was successfully obtained. [ABSTRACT FROM AUTHOR]

An empirical parametrization for the production cross sections of 238U photofission fragments at low energies (Eγ<30 MeV) is developed. This parametrization, GIF238U, consists of three parts, namely, the photofission cross section, the mass yield, and the isobaric charge distribution. The photofission cross section is parametrized to reproduce measured data over a wide energy range. The mass yield distribution is described by the energy-dependent multimodal fission model. The isobaric charge distribution is improved, relative to other parametrizations, to describe many experimental data sets over a broad mass range. Comparisons with different measured 238U photofission data sets at various energies reveal that GIF238U is in very good agreement with measured elemental and mass yields and can accurately reproduce experimental isotopic yields. Production cross sections (yields) of photofission fragments calculated by this parametrization indicate that many neutron-rich nuclei approaching the r-process path can be accessed via photofission of 238U at radioactive-beam facilities. [ABSTRACT FROM AUTHOR]

The quadrupole interaction of high-spin isomers in 193Pb implanted into solid Hg cooled at a temperature T = 170 K has been investigated by the time-differential perturbed γ-ray angular-distribution method. Spectroscopic quadrupole moment values of &verbar;Qs&verbar; = 0.22(2) eb and 0.45(4) eb have been deduced for the 21/2- and 33/2+ three-neutron states, respectively. A much higher value &verbar;Qs&verbar; = 2.84(26) eb has been determined for the 29/2- isomer, the band head of a magnetic rotational band. [ABSTRACT FROM AUTHOR]

We report the results from the first experiment to measure gyromagnetic factors of μs isomers in neutron-rich nuclei produced by intermediate-energy projectile-fragmentation reactions. The Time Dependent Perturbed Angular Distribution (TDPAD) method was applied in combination with the heavy-ion-gamma correlation technique. The nuclides in the vicinity of 68Ni were produced and spin-oriented following the fragmentation of a 76Ge, 61.4 MeV/u beam at GANIL. The results obtained, |g|(69mCu) = 0.225(25) and |g|(67mNi) = 0.125(6) provide another indication of the importance of proton excitation across the Z = 28 shell gap for the description of these states. [ABSTRACT FROM AUTHOR]

Post-accelerated isomerically purified radioactive beams, available at the CERN On-Line Isotope Mass Separator facility using the resonant ionization laser technique, have been used to study the Coulomb excitation of the I&pi; = 3- state in 70Cu (Z = 29, N = 41). While first results using a Iπ =6- beam were reported previously, the present complementary experiment allows us to complete the study of the multiplet of states (3-, 4- ,5-,6-) arising from the π2p3νlg9/2 configuration. Besides the known γ-ray transition deexciting the 4- state, a ground-state γ ray of 511(3) keV was observed for the first time and was unambiguously associated with the 5- state deexcitation. This observation fixes the energy, spin, and parity of this state, completing the low-energy level scheme of 70Cu. B(E2) values for all possible E2 transitions within the multiplet were determined. A comparison with large-scale shell model calculations using different interactions and valence spaces shows the importance of proton excitation across the Z = 28 shell gap and the role of the 2d5/2 neutron orbital. [ABSTRACT FROM AUTHOR]

Excited states of the neutron-rich nuclei 97,99Rb were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of 97Rb as being built on the pg9/2 [431] 3/2+ Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N=60 and rotational bands above. The present study defines the limits of the deformed region around A~100 and indicates that the deformation of 97Rb is essentially the same as that observed well inside the deformed region. It further highlights the power of the Coulomb-excitation technique for obtaining spectroscopic information far from stability. The 99Rb case demonstrates the challenges of studies with very short-lived postaccelerated radioactive beams. [ABSTRACT FROM AUTHOR]

The high-velocity transient-field (HVTF) technique was used to measure the g factor of the 2+ state of 72Zn produced as a radioactive beam. The transient-field strength was probed at high velocity in ferromagnetic iron and gadolinium hosts using 76Ge beams. The potential of the HVTF method is demonstrated and the difficulties that need to be overcome for a reliable use of the TF technique with high-Z, high-velocity radioactive beams are revealed. The polarization of K-shell vacancies at high velocity, which shows more than an order of magnitude difference between Z = 20 and Z = 30 is discussed. The g-factor measurement hints at the theoretically predicted transition in the structure of the Zn isotopes near N = 40. [ABSTRACT FROM AUTHOR]