A. Y. Deo

Schottky mass measurements of heavy neutron-rich nuclides in the element range 70 <= Z <= 79 at the GSI Experimental Storage Ring

D. Shubina, 2, 3 R.B. Cakirli, 4 Yu.A. Litvinov, 3 K. Blaum, C. Brandau, 5 F. Bosch, J.J. Carroll, R.F. Casten, D.M. Cullen, I.J. Cullen, A.Y. Deo, B. Detwiler, C. Dimopoulou, F. Farinon, H. Geissel, 11 E. Haettner, M. Heil, R.S. Kempley, C. Kozhuharov, R. Knobel, J. Kurcewicz, N. Kuzminchuk, S.A. Litvinov, Z. Liu, R. Mao, C. Nociforo, F. Nolden, Z. Patyk, W.R. Plass, A. Prochazka, M.W. Reed, 15 M.S. Sanjari, 16 C. Scheidenberger, 11 M. Steck, Th. Stohlker, 17, 18 B. Sun, 19 T.P.D. Swan, G. Trees, P.M. Walker, 20 H. Weick, N. Winckler, 3 M. Winkler, P.J. Woods, T. Yamaguchi, and C. Zhou Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany Fakultat fur Physik und Astronomie, Universitat Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany GSI Helmholtzzentrum fur Schwerionenforschung, Planckstrase 1, 64291 Darmstadt, Germany Department of Physics, University of Istanbul, Istanbul, Turkey ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fur Schwerionenforschung, 64291 Darmstadt, Germany US Army Research Laboratory, 2800 Powder Mill Road, Adelphi MD, USA Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA Schuster Laboratory, University of Manchester, Manchester M13 9PL, United Kingdom Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom Youngstown State University, One University Plaza, Youngstown, Ohio 44555, USA II Physikalisches Institut, Justus-Liebig-Universitat Giesen, 35392 Giesen, Germany School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, People’s Republic of China National Centre for Nuclear Research, PL-00681 Warsaw, Poland Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra ACT 0200, Australia Goethe-Universitat Frankfurt, 60438 Frankfurt, Germany Friedrich-Schiller-Universitat Jena, 07737 Jena, Germany Helmholtz-Institut Jena, 07743 Jena, Germany School of Physics and Nuclear Energy Engineering, Beihang University, 100191 Beijing, PRC CERN, CH-1211 Geneva 23, Switzerland Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan Storage-ring mass spectrometry was applied to neutron-rich Au projectile fragments. Masses of Lu, Hf, Ta, W, and Re nuclei were measured for the first time. The uncertainty of previously known masses of W and Os nuclei was improved. Observed irregularities on the smooth two-neutron separation energies for Hf and W isotopes are linked to the collectivity phenomena in the corresponding nuclei.

Technique for Resolving Low-lying Isomers in the Experimental Storage Ring (ESR) and the Occurrence of an Isomeric State in 192Re

A recent experiment using projectile fragmentation of a 197Au beam on a 9Be target, combined with the fragment recoil separator and experimental storage ring at ring at GSI, has uncovered an isomeric state in 192Re at 267(10) keV with a half-life of ~60 s. The data analysis technique used to resolve the isomeric state from the ground state is discussed.

Trap-assisted separation of nuclear states for gamma-ray spectroscopy: the example of 100Nb

Low-lying levels in 100Mo are known to be populated by beta decay from both the ground and isomeric states in 100Nb. The small energy difference (~3 ppm) between the two parent states and the similarity of their half-lives make it difficult to distinguish experimentally between the two decay paths. A new technique for separating different states of nuclei has recently been developed in a series of experiments at the IGISOL facility, using the JYFLTRAP installation, at the University of Jyvaskyla where mass resolution ~2 ppm was achieved in mass measurements and in the production of 133mXe. This paper reports on the extension of this technique to allow the separate study of the gamma-ray decay of levels populated by the different parent states.

Increased lifetime of hydrogen-like

A. Akber1, M.W. Reed1, P.M. Walker2, I.J. Cullen2, Yu.A. Litvinov3,4,5, K. Blaum3,5, F. Bosch4, C. Brandau4,6, J.J. Carroll7, D.M. Cullen8, A.Y. Deo2, B. Detwiler9, C. Dimopoulou4, G.D. Dracoulis1, F. Farinon4, H. Geissel4,10, E. Haettner10, M. Heil4, R.S. Kempley2, T. Kibédi1, R. Knöbel4,10, C. Kozhuharov4, J. Kurcewicz4,11, N. Kuzminchuk4,10, G.J Lane1, S. Litvinov4, Z. Liu12,13, R. Mao13, C. Nociforo4, F. Nolden4, W.R. Plass4,10, A. Prochazka4, C. Scheidenberger4,10, D. Shubina3,5, M. Steck4, Th. Stöhlker4,14,15, B. Sun4, T.P.D. Swan2, G. Trees9, H. Weick4, N. Winckler3,4, M. Winkler4, P.J. Woods12, and T. Yamaguchi16 1Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra ACT 0200, Australia; 2Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; 3Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany; 4GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany; 5Physikalisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany; 6ExtreMe Matter Institute EMMI, 64291 Darmstadt, Germany; 7US Army Research Laboratory, 2800 Powder Mill,Road, Adelphi MD, USA; 8Schuster Laboratory, University of Manchester, Manchester M13 9PL, United Kingdom; 9Youngstown State University, One University Plaza, Youngstown, Ohio 44555, USA; 10II Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany; 11CERN, 1211 Geneva 23, Switzerland; 12School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom; 13Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China; 14Institute of Physics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany; 15Helmholtz-Institut Jena, Fröbelstieg 3, 07743 Jena, Germany; 16Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan Using the Experimental Storage Ring (ESR) it is possible to distinguish between charge states of an isotope with sensitivity down to single ions [1]. Projectile fragmentation of a Au beam (478-492 A·MeV) with a Be target was performed and the resultant fragments were passed through the FRagment Separator [2] where isotopes of interest were separted before being injected into the ESR. The ions were cooled by electron and stochastic cooling enabling Schottky Mass Spectrometry to be used and nuclear decays within the ESR are inferred from changes in ion revolution frequency [3]. Prior studies of Os revealed an isomer with a lifetime of τneut = 8.5(14) s at 2015 keV. Three decay branches have been observed with transition energies of 47, 302, and 307 keV [4]. Neutral [5] and hydrogen-like internal conversion coefficients were calculated and indicate a decrease for all transitions (Table 1). For the 47 keV transition internal conversion in the hydrogen-like state is forbidden. An increased lifetime of τcalc = 13.0(24) s due to the reduction of internal conversion can be expected.

^{192m}Os

The population of 102Zr following the β decay of 102Y produced in the projectile fission of 238U at the GSI facility in Darmstadt, Germany has been studied. 102Y is known to s decay into 102Zr via two states, one of high spin and the other low spin. These states preferentially populate different levels in the 102Zr daughter. In this paper the intensities of transitions in 102Zr observed are compared with those from the decay of the low-spin level studied at the TRISTAN facility at Brookhaven National Laboratory and of the high-spin level studied at the JOSEF separator at the Kernforschungsanlage Julich.

observed in the ESR

The population of 102Zr following the β decay of 102Y produced in the projectile fission of 238U at the GSI facility in Darmstadt, Germany has been studied. 102Y is known to s decay into 102Zr via two states, one of high spin and the other low spin. These states preferentially populate different levels in the 102Zr daughter. In this paper the intensities of transitions in 102Zr observed are compared with those from the decay of the low-spin level studied at the TRISTAN facility at Brookhaven National Laboratory and of the high-spin level studied at the JOSEF separator at the Kernforschungsanlage Julich.

βdecay of102Y produced in projectile fission of238U

The population of 102Zr following the β decay of 102Y produced in the projectile fission of 238U at the GSI facility in Darmstadt, Germany has been studied. 102Y is known to s decay into 102Zr via two states, one of high spin and the other low spin. These states preferentially populate different levels in the 102Zr daughter. In this paper the intensities of transitions in 102Zr observed are compared with those from the decay of the low-spin level studied at the TRISTAN facility at Brookhaven National Laboratory and of the high-spin level studied at the JOSEF separator at the Kernforschungsanlage Julich.

β decay of 102Y produced in projectile fission of 238U

Neutron-rich nuclei beyond N = 126 in the lead region were populated by fragmenting a 238U beam at 1 GeV A on a Be target and then separated by the Fragment Separator (FRS) at GSI. Their isomeric decays were observed, enabling study of the shell structure of neutron-rich nuclei around the Z=82 shell closure. Some preliminary results are reported in this paper.

Beta Decay of 102Y Produced in Projectile Fission of 238U

Several low-lying excited states in {sub 86}{sup 205}Rn{sub 119} and {sub 84}{sup 201}Po{sub 117} were identified for the first time following EC/{beta}{sup +} decay of {sup 205}Fr and {sup 201}At, respectively, using {gamma}-ray and conversion electron spectroscopy at the CERN isotope separator on-line (ISOLDE) facility. The EC/{beta}{sup +} branch from {sup 205}Fr was measured to be 1.5(2)%. The excited states of the daughter nuclei are understood in terms of the odd nucleon coupling to the neighboring even-even core. The neutron single-particle energies of the p{sub 3/2} orbital relative to the f{sub 5/2} ground state in {sup 205}Rn, and the f{sub 5/2} orbital relative to the p{sub 3/2} ground state in {sup 201}Po, were determined to be 31.4(2) and 5.7(3) keV, respectively. We tentatively identify a (13/2){sup +} isomeric level at 657.1(5) keV in {sup 205}Rn. The systematic behavior of the (13/2){sup +} and (3/2){sup -} levels is also discussed.Financial support from the UK STFC and AWE plc, the Spanish MEC FPA2007-07393, CSPD-2007-00042 CPAN, FPA2005-03993, and FPA 2008-06419-C02-01 projects. Partial support from the Ramon y Cajal program.

Isomers in Neutron-rich Lead Isotopes Populated via the Fragmentation of 238U at 1 GeV A

In order to determine the Gamow‐Teller strength distribution for the N = Z nucleus 72Kr an experiment was performed with a Total Absorption Gamma Spectrometer. To fully accomplish this task it is crucial to determine the multipolarity of the low energy transitions as the spin‐parity of the daughter ground state has been debated. This is done by experimental determination of the conversion coefficients. Preliminary results for the multipolarity and conversion coefficients of the transition connecting the isomeric state at 101 keV with the 72Br ground state are presented.