Magnetic moments of the first excited states in 50Cr and of the 7/2" and 19/2' states in 49Cr, have been measured by the transient field technique. The states were excited by the inverse reaction 40Ca + 12C and the recoil nuclei traversed a thick gadolinium foil. The observed rotations, of the 2+, 4+, 6+, 8+ states of the ground-state band in 50Cr, were found into the experimental error to be the same, suggesting similar g-factors for these states and thus supporting a high collectivity for the ground-state band, g-factors of the 7/2' and 19/2 states in 49Cr, were deduced by adopting both an overall parametrization of the transient magnetic field in Gd and by comparing the 49Cr rotations with rotations of states with known magnetic moments, as the 2+ ones of 50Cr and of 46Ti which was also populated in the same reaction. Both methods gave similar results and the g-factors adopted for the 19/2" and 7/2" states were + 0.78(17) and +0.35(7) respectively. These results are discussed in terms of cranked shell model calculations and are found to support a proton alignment in the f7/2 shell.

The transitional nuclei Xe-132 and Xe-133 are investigated after multinucleon-transfer (MNT) and fusionevaporation reactions. Both nuclei are populated (i) in Xe-136 + 2(08P)b MNT reactions employing the highresolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the Xe-136 + Pt-198 MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a Te-130(alpha, xn) Xe134-xn fusion-evaporation reaction employing the HORUS gamma-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the J(pi) = (7(-)) and (10+) isomers in Xe-132 and above the 11/2(-) isomer in Xe-133. The results are compared to the high-spin systematics of the Z = 54 as well as the N = 78 and N = 79 chains. Furthermore, evidence is found for a long-lived (T-1/2 >> mu s) isomer in Xe-133 which closes a gap along the N = isotones. Shell-model calculations employing the SN100PN and PQM130 effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features.

The 50 � N,Z � 82 region of the Segre chart, spanning the nuclei “northwest” of doubly-magic 132Sn, is an intriguing study ground to test the suitability and predictive power of nuclear models at both low and high spins. Low-spin excited states in the nearly spherical nuclei near proton- and neutronshell closures are well described as anharmonic vibrations [1] with a gradual change to rotational structures further away from the closed shells. Further on, quasiparticle excitations play a key role and are responsible for the presence of yrast-trap isomers. These long-lived states interrupt and fragment the decay flux in spectroscopic investigations. High-j couplings involving the unique-parity h11/2 neutron-hole orbital give rise to a wealth of high-spin states with multi-quasiparticle character. In particular, detailed knowledge of isomers is crucial to ascertain the active quasiparticle configurations in the specific nucleus.

© 2017 American Physical Society. The high-spin structures and isomers of the N=81 isotones Xe135 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in Xe136+U238 and (ii) Xe136+Pb208 MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii) in the Xe136+Pt198 MNT reaction employing the γ-ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a B11+Te130 fusion-evaporation reaction with the HORUS γ-ray array at the University of Cologne. The high-spin level schemesof Xe135 and Ba137 are considerably extended to higher energies. The 2058-keV (19/2-) state in Xe135 is identified as an isomer, closing a gap in the systematics along the N=81 isotones. Its half-life is measured to be 9.0(9) ns, corresponding to a reduced transition probability of B(E2,19/2-→15/2-)=0.52(6) W.u. The experimentally deduced reduced transition probabilities of the isomeric states are compared to shell-model predictions. Latest shell-model calculations reproduce the experimental findings generally well and provide guidance to the interpretation of the new levels.

Citation for published version (APA): Vogt, A., Siciliano, M., Birkenbach, B., Reiter, P., Hadynska-Klek, K., Wheldon, C., Valiente Dobon, JJ., Teruya, E., Yoshinaga, N., Arnswald, K., Bazzacco, D., Blazhev, A., Bracco, A., Bruyneel, B., Chakrawarthy, R. S., Chapman, R., Cline, D., Corradi, L., Crespi, F. C. L., ... Zell, K. O. (2017). High-spin structures in 132 Xe and 133 Xe and evidence for isomers along the N = 79 isotones. Physical Review C (Nuclear Physics), 96, [024321]. https://doi.org/10.1103/PhysRevC.96.024321

Detailed spectroscopic information on the N ∼ 82 nuclei is necessary to benchmark shell-model calculations in the region. The nuclear structure above long-lived isomers in 134 Xe is investigated after multinucleon transfer (MNT) and actinide fission. Xenon-134 was populated as (i) a transfer product in 136 Xe + 238 U and 136 Xe + 208 Pb MNT reactions and (ii) as a fission product in the 136 Xe + 238 U reaction employing the high-resolution Advanced Gamma Tracking Array (AGATA). Trajectory reconstruction has been applied for the complete identification of beamliketransferproductswiththemagneticspectrometerPRISMA.The 136 Xe + 198 PtMNTreactionwasstudied with the γ -ray spectrometer GAMMASPHERE in combination with the gas detector array Compact Heavy Ion Counter (CHICO). Several high-spin states in 134 Xe on top of the two long-lived isomers are discovered based on γγ -coincidence relationships and information on the γ -ray angular distributions as well as excitation energies from the total kinetic energy loss and fission fragments. The revised level scheme of 134 Xe is extended up to an excitation energy of 5.832 MeV with tentative spin-parity assignments up to 16 + . Previous assignments of states above the 7 − isomer are revised. Latest shell-model calculations employing two different effective interactions reproduce the experimental findings and support the new spin and parity assignments. DOI: 10.1103/PhysRevC.93.054325

Several strongly coupled bands in the neutron-deficient nucleus Ta-161 have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for Ta-161 highlights the competition between the.(h(9/2)) and.(i(13/2)) orbitals to form the yrast spectrum. The band structures in Ta-161 also provide new insights into the structural features of other heavy odd-A nuclei populated with much lower reaction cross sections in this region at the proton drip line.

Excited states in the neutron-deficient odd-Z nuclide Ta-161 were identified for the first time using the Cd-106(Ni-58,3p gamma) reaction at a beam energy of 270 MeV. The pi h(11/2) band, yrast at low spin, was observed up to (47/2(-)) and a further four strongly coupled bands have been established to high spin. Quasiparticle configuration assignments for the new band structures have been made on the basis of cranked shell model calculations. This work suggests that the negative-parity nu(f(7/2), h(9/2)) orbitals are responsible for the first rotational alignment in the pi h(11/2) band.

W.N. Catford, C.N. Timis, R. C. Lemmon, M. Labiche, N.A. Orr, B. Fernández-Domı́nguez, R. Chapman, M. Freer, M. Chartier, H. Savajols, M. Rejmund, N. L. Achouri, N. Amzal, N. I. Ashwood, T. D. Baldwin, M. Burns, L. Caballero, J.M. Casadjian, N. Curtis, G. de France, W. Gelletly, X. Liang, S. D. Pain, V. P. E. Pucknell, B. Rubio, O. Sorlin, K. Spohr, Ch. Theisen, and D.D. Warner Department of Physics, University of Surrey, Guildford GU2 5XH, United Kingdom Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom School of Engineering and Science, University of the West of Scotland, Paisley PA1 2BE, United Kingdom LPC–ENSICAEN, IN2P3/CNRS et Université de Caen, 14050 Caen, France Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom GANIL, BP 55027, 14076 Caen Cedex 5, France Instituto de Fisica Corpuscular, CSIC-Universidad de Valencia, 46071 Valencia, Spain IRFU, CEA-Saclay, 91191 Gif-sur-Yvette, France (Received 22 September 2009; published 10 May 2010)

A compact, quasi-4pi position sensitive silicon array, TIARA, designed to study direct reactions induced by radioactive beams in inverse kinematics is described here. The Transfer and Inelastic All-angle Reaction Array (TIARA) consists of 8 resistive charge division detectors forming an octagonal barrel around the target and a set of double-sided silicon-strip annular detectors positioned at each end of the barrel. The detector was coupled to the -ray array EXOGAM and the spectrometer VAMOS at the GANIL Laboratory to demonstrate the potential of such an apparatus with radioactive beams. The 14N(d,p)15N reaction, well known in direct kinematics, has been carried out in inverse kinematics for that purpose. The observation of the 15N ground state and excited states at 7.16 and 7.86 MeV is presented here as well as the comparison of the measured proton angular distributions with DWBA calculations. Transferred l-values are in very good agreement with both theoretical calculations and previous experimental results obtained in direct kinematics.

We report here on the first results obtained from the study of the 24Ne(d, p)25Ne reaction performed with SPIRAL beam at GANIL using the new TIARA+V AMOS+EXOGAM setup.

Gamma rays populating the alpha-decaying isomeric state in Ir-169 have been observed for the first time. The experiment employed the recoil-decay tagging method using the JUROGAM gamma-ray spectrometer, the RITU gas-filled recoil separator and the GREAT spectrometer located at the RITU focal plane. The gamma-ray cascade feeding the isomeric alpha-decaying state exhibits a rotational structure consistent with a h(11/2) proton coupled to a triaxially deformed core. The experimental results are compared with predictions from total Routhian surface calculations.

Excited states in $^{46}\mathrm{Cr}$ were sought using the $^{12}\mathrm{C}$($^{36}\mathrm{Ar}$,$2n$) reaction. Gamma rays were detected with the Gammasphere array, and the $Z$ value of the reaction products was determined with an ionization chamber located at the focal plane of the Fragment Mass Analyzer. In addition to the ground-state band observed up to ${I}^{\ensuremath{\pi}}={10}^{+}$ (tentatively ${12}^{+}$), five states are proposed to belong to the ${3}^{\ensuremath{-}}$ band. The mirror energy differences with the analog states in $^{46}\mathrm{Ti}$ present a pronounced staggering effect between the odd and even spin members that is reproduced well by shell-model calculations incorporating the different Coulomb contributions, monopole, multipole, and single-particle effects together with an isospin-nonconserving interaction that accounts for the so-called $J=2$ anomaly. Dramatically different $E1$ decay patterns for members of the ${3}^{\ensuremath{-}}$ band between the $^{46}\mathrm{Cr}$ and $^{46}\mathrm{Ti}$ mirrors are also observed.

S.F. Ashley, A. Linnemann, J. Jolie, P.H. Regan K. Andgrena,c, A. Dewald, E.A. McCutchan, B. Melon O. Möller, N.V. Zamfird,e, L. Amond,f , N. Boelaertb,g R.B. Cakirlid,f , R.F. Casten, R.M. Clark, C. Fransen W. Gelletly, G. Gürdald,i, M. Heidemann, K.L. Keyes M.N-. Erduran , D.A. Meyer, A. Papenberg, C. Plettner G. Rainovski, R.V. Ribas, N.J. Thomasa,c, J. Vinson D.D. Warner, V. Werner, E. Williams, K.O. Zell