Neutron-rich silver isotopes were populated in the fragmentation of a Xe-136 beam and the relativistic fission of U-238. The fragments were mass analyzed with the GSI Fragment Separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 high-purity germanium detectors. Eight isomeric states were observed in Ag122-126 nuclei. The level schemes of Ag-122,Ag-123,Ag-125 were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data. DOI: 10.1103/PhysRevC.87.034308

We have investigated nuclear fragmentation reactions of a relativistic Pb-208 beam. Ten isomeric states for nuclei with A = 142-152 and Z = 62-67 were observed. Measured isomeric ratios were compared, together with values from other experiments, with prediction of theoretical models. The discrepancies between the experimental and theoretical values were discussed in terms of transitions by-passing the isomer that are not included in the models.

The F-4(3/2) state of Nd3+ dopant ions is split due to the crystal field at orthorhombic D-2 symmetry sites in several members of the garnet family of crystals. In the gadolinium-gallium garnet crystal this splitting is found to almost disappear under hydrostatic pressures between 8 and 11 GPa created in the diamond-anvil cell. This pressure is much lower than that required for the phase transition to the so called high-pressure phase. This effect is explained with help of x-ray diffraction, optical spectroscopy, and ab initio calculations as an effect of accidental near-degeneracy arising from a particular lattice structure of garnets.

Isomeric states in the semimagic Sn128-130 isotopes were populated in the fragmentation of a Xe-136 beam on a Be-9 target at an energy of 750 A.MeV. The decay of an isomeric state in Sn-128 at an excitation energy of 4098 keV has been observed. Its half live has been determined to be T-1/2 = 220(30) ns from the time distributions of the delayed gamma rays emitted in its decay. gamma gamma coincidence relations were analyzed in order to establish the decay pattern of the newly established state toward the known (7(-)) and (10(+)) isomers at excitation energies of 2092 and 2492 keV, respectively. Based on a comparison with results of state-of-the-art shell-model calculations the new isomeric state is proposed to have the nu h(11/2)(-3)d(3/2)(-1) configuration with the four neutron holes in Sn-132 maximally aligned to a total spin of I-pi = 15(-).

Heavy neutron-rich nuclei were populated via the fragmentation of a E/A = 1 GeV Pb-208(82) beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed gamma rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in Hg-204,205(80), Au-201,202,204,205(79), Pt-197,203,204(78), Ir-195,199-203(77), Os-193,197-199(76), Re-196(75), W-190,191(74), and Ta-189(73). Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed.

F. Naqvi,1,2,* M. Górska,2 L. Cáceres,2,3,† A. Jungclaus,4 M. Pfützner,5 H. Grawe,2 F. Nowacki,6 K. Sieja,6 S. Pietri,7,‡ E. Werner-Malento,5,§ P. H. Regan,7 D. Rudolf,8 Z. Podolyák,7 J. Jolie,1 K. Andgren,9 T. Beck,2 P. Bednarczyk,2,10 J. Benlliure,11 G. Benzoni,12 A. M. Bruce,13 E. Casarejos,11,‖ B. Cederwall,9 F. C. L. Crespi,12,14 P. Detistov,15,¶ Zs. Dombrádi,16 P. Doornenbal,2,** H. Geissel,2 J. Gerl,2 J. Grębosz,2,10 B. Hadinia,9 M. Hellström,8 R. Hoischen,2,8 G. Ilie,1,†† A. Khaplanov,9 I. Kojouharov,2 M. Kmiecik,10 N. Kurz,2 S. Lalkovski,13,15 A. Maj,10 S. Mandal,17 V. Modamio,3 F. Montes,2,‡‡ S. Myalski,10 W. Prokopowicz,2 P. Reiter,1 H. Schaffner,2 G. Simpson,18 D. Sohler,19 S. J. Steer,7 S. Tashenov,2 J. Walker,3 O. Wieland,12 and H. J. Wollersheim2 1Institut für Kernphysik, Universität zu Köln, D-50937 Köln, Germany 2Helmholtzzentrum für Schwerionenforschung (GSI), D-64291 Darmstadt, Germany 3Departmento de Fı́sica Teórica, Universidad Autónoma de Madrid, E-28049 Madrid, Spain 4Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain 5Faculty of Physics, University of Warsaw, PL-00681 Warsaw, Poland 6IPHC, IN2P3-CNRS/Université Louis Pasteur, F-67037, Strasbourg, France 7Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom 8Department of Physics, Lund University, S-22100 Lund, Sweden 9KTH Stockholm, S-10691 Stockholm, Sweden 10The Henryk Niewodniczański Institute of Nuclear Physics, PL-31342 Kraków, Poland 11Universidad de Santiago de Compostela, E-175706 Santiago de Compostela, Spain 12INFN Sezione di Milano, I-20133 Milano, Italy 13School of Engineering, University of Brighton, Brighton, BN2 4GJ, United Kingdom 14Universitá degli Studi di Milano, I-20133 Milano, Italy 15Faculty of Physics, University of Sofia, BG-1164, Sofia, Bulgaria 16Institute National Polytechnique de Grenoble, F-98026 Grenoble Cedex, France 17University of Delhi, New Delhi, India 18Institut Laue-Langevin, F-38042 Grenoble, France 19Institute of Nuclear Research, Pf. 51, H-4001 Debrecen, Hungary

The spin and configurational structure of excited states of 127 Cd, the two-proton and three-neutron hole neighbor of 132 Sn, has been studied. An isomeric state with a half-life of 17.5(3) μs was populated in the fragmentation of a 136 Xe beam on a 9 Be target at a beam energy of 750 MeV/u. Time distributions of the delayed γ transitions and γγ coincidence relations were exploited to construct a decay scheme. The observed yrast (19/2) + isomer is proposed to have dominant configurations of ν(h ―3 11/2 )π(g ―1 9/2 , p ―1 1/2 ), ν(h ―2 11/2 d ―1 3/2 )π(g ―2 9/2 ), and ν(h ―2 11/2 , s ―1 1/2 )π(g ―2 9/2 ) and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone 129 Sn. The new information provides input for the proton-neutron interaction and the evolution of neutron hole energies in nuclei around the doubly magic 132 Sn core.

Rare-earth doped nanocrystalline yttria-stabilized zirconia (YSZ, ZrO2-Y2O3) is, recently, a subject of studies because of its luminescent properties. The luminescence may be strongly influenced by the crystal structure and microstructure of the material. In this work, the X-ray diffraction study for Pr doped YSZ nanocrystals is presented. The phase composition dependence on the Y2O3 content and on heat treatment conditions is quantitatively determined using the Rietveld method and the similarities and differences between the present data for doped samples and earlier reported data for undoped material are discussed. A formation of high symmetry phases (cubic and tetragonal) is observed for high yttria content in agreement with general tendencies observed in literature for undoped samples.

The photon spectrum accompanying the orbital K-electron capture in the first-forbidden unique decay of 81Kr was measured. The total radiation intensity for photon energies larger than 50 keV was found to be 1.42(22)×10-4 per K capture. Both the shape of the spectrum and its intensity relative to the ordinary, nonradiative capture rate are compared to theoretical predictions. The best agreement is found for the recently developed model that employs the length gauge for the electromagnetic field.

. The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV ^π=12^+ isomer in 192 Pb with τ = 1.57 μs has been produced using the fragmentation of a 1 A GeV 238 U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)

We report on g-factor measurements of the 19/2+ T1/2=4.5(3) μs isomer in 127Sn and the 10+ T1/2=2.69(23) μs isomer in 128Sn. These isomers were produced and spin-aligned in relativistic heavy-ion fragmentation at GSI and were selected and separated by the GSI fragment separator (FRS). The γ-rays of the isomeric decay were detected by the RISING γ-ray spectrometer. The method of time-differential perturbed angular distributions was utilized. The measured g-factors, g(19/2+; 127Sn)=− 0.17(2) and g(10+; 128Sn)=− 0.20(4), are compared with shell model calculations. The measured g-factors confirm the predominantly νh11/2− 2 and ν(s1/2− 1h11/2−2) character of the 10+ and 19/2− isomers in 128Sn and 127Sn, respectively. The results demonstrate the feasibility of the method for similar measurements in exotic neutron-rich nuclei.

S. Mianowski, E. Werner-Malento, ∗ A. Korgul, M. Pomorski, K. Pachucki, M. Pfützner, † B. Szweryn, J. ›ylicz, P. Hornshøj, T. Nilsson, 4 and K. Rykaczewski Physics Department, University of Warsaw, Ho»a 69, 00-681 Warsaw, Poland Institute of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark Fundamental Physics, Chalmers University of Technology, Gothenburg, Sweden CERN, EP-Division, CH-1211, Geneva 23, Switzerland Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA (Dated: August 5, 2010)

The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV \(\ensuremath I^{\pi}=12^+\) isomer in 192Pb with \( \tau\) = 1.57 μs has been produced using the fragmentation of a 1A GeV 238U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, \( \tau\) = 1.54(9) μs, and the g -factor, g = - 0.175(20) , agree with the results of previous investigations using fusion-evaporation reactions.

Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a \(\ensuremath ^{208}_{\ 82}{\rm Pb}\) beam at \(\ensuremath E/A = 1\) GeV on a \(\ensuremath 2.5 {\rm g/cm^2}\) thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an \(\ensuremath \sim 8\) mm thick perspex stopper, positioned at the centre of the RISING \(\ensuremath \gamma\) -ray detector spectrometer array. A previously unreported isomer with a half-life \(\ensuremath T_{1/2} = 163(5)\) ns has been observed in the N = 126 closed-shell nucleus \(\ensuremath ^{205}_{\ 79}{\rm Au}\) . Through \( \gamma\) -ray singles and \( \gamma\) -\( \gamma\) coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be \(\ensuremath I^{\pi} = (19/2^+)\) .

Gamma rays from the decay of an isomer in 190W116 have been observed following projectile fragmentation of a 1 GeV per nucleon 208Pb beam. An earlier experiment indicated decay from a (10-) isomer to the ground state rotational band. Improved statistics have enabled gamma coincidence and time-difference measurements to be made which alter the previous interpretation. Blocked BCS calculations have also been used together with reduced hindrance factors to indicate possible values of spin-parity for the isomer.

Heavy neutron-rich nuclei were populated via relativistic energy fragmentation of a E / A = 1 GeV 208 Pb beam. The nuclei of interest were selected and identified by a fragment separator and then implanted in a passive plastic stopper. Delayed γ rays following internal isomeric decays were detected by the RISING array. Experimental information was obtained on a number of nuclei with Z = 73-80 ( Ta - Hg ), providing new information both on the prolate-oblate transitional region as well as on the N = 126 closed shell nuclei.

Gamma rays de-exciting isomeric states in the neutron-rich nucleus Os-198(76)122 have been observed following relativistic projectile fragmentation of a 1 GeV per nucleon Pb-208 beam. The ground-state band has properties compatible with oblate deformation. The evolution of the structure of Os isotopes characterized by sudden prolate-oblate shape change is discussed and contrasted with the smooth change known in the Pt chain.

The relativistic projectile fragmentation of a 750 MeV per nucleon beam of Ag-107 was used to populate isomeric states in neutron-deficient nuclei around A=80-90. Reaction products were separated and unambiguously identified using the GSI FRagment Separator (FRS) and its ancillary detectors. At the final focal plane, the fragments were slowed from relativistic energies by means of an aluminium degrader and implanted in a passive stopper in the center of the high-efficiency, high-granularity Stopped Rare Isotope Spectroscopic INvestigation at GSI (RISING) germanium array. This allowed the identification of excited states in the N=Z nuclei Tc-86(43) and, for the first time, Nb-82(41). Isomeric states have also been identified for the first time in Tc-87,Tc-88, and a previously unreported isomer was observed in Nb-84. Experimental results are presented along with a discussion on the structure of these nuclei based on interpretations provided by several theoretical models.

Isomeric states in nuclei with Z = 62-67 and A = 142-152 produced in the fragmentation of the relativistic (1 GeV/nucleon) Pb-208 beam were investigated. Isomeric ratios were determined for 10 isomeric states. Significant differences between theoretical and experimental values were observed.