Search

Your search keyword '"A, Dewald"' showing total 96 results
Start Over Author "A, Dewald" Journal aip conference proceedings
96 results on '"A, Dewald"'

1. Lifetime Measurement of the 2[sub 1][sup +] state in [sup 20]C

Author

M. Petri, P. Fallon, A. O. Macchiavelli, S. Paschalis, K. Starosta, T. Baugher, D. Bazin, L. Cartegni, R. M. Clark, H. L. Crawford, M. Cromaz, A. Dewald, A. Gade, G. F. Grinyer, S. Gros, M. Hackstein, H. B. Jeppesen, I. Y. Lee, S. McDaniel, D. Miller, M. M. Rajabali, A. Ratkiewicz, W. Rother, P. Voss, K. A. Walsh, D. Weisshaar, M. Wiedeking, Paraskevi Demetriou, Rauno Julin, and Sotirios Harissopulos

Subjects
Recoil, Isotope, Chemistry, Binding energy, Nuclear structure, Value (computer science), Gamma spectroscopy, Nuclide, Atomic physics, Space (mathematics)
Abstract

The mean lifetime of the 21+ state in the near drip‐line nuclide 20C was measured for the first time using the Recoil Distance Method with intermediate energy radioactive beams via a knockout reaction. The measured value of τ21+ = 9.8±2.8(stat)−1.1+0.5(syst) ps gives a reduced transition probability of B(E2;21+→0g.s.+) = 7.51.7+3.0(stat) e2fm4. This value is in good agreement with shell model calculations using a p—sd shell model space and isospin‐dependent (N—Z) effective charges.

Published
2011
Full Text
View/download PDF

2. Lifetime measurement in the proton-unbound nucleus [sup 109]I

Author

M. G. Procter, D. M. Cullen, P. Ruotsalainen, C. Scholey, L. Angus, T. Bäck, B. Cederwall, A. Dewald, C. Fransen, T. Grahn, P. T. Greenlees, M. Hackstein, U. Jakobsson, P. M. Jones, R. Julin, S. Juutinen, S. Ketelhut, M. Leino, N. M. Lumley, P. J. R. Mason, P. Nieminen, M. Nyman, J. Pakarinen, T. Pissulla, P. Peura, P. Rahkila, J. Revill, S. V. Rigby, W. Rother, M. Sandzelius, J. Sarén, J. Sorri, M. J. Taylor, J. Uusitalo, P. Wady, C. Qi, F. R. Xu, and Bertram Blank

Subjects
Nuclear physics, Physics, Valence (chemistry), medicine.anatomical_structure, ta114, Excited state, Nuclear Theory, SHELL model, medicine, Atomic physics, Nuclear Experiment, Nucleon, Nucleus
Abstract

The Recoil‐Distance Doppler‐shift method has been combined with Recoil‐Decay Tagging for the first time to measure a lifetime in the proton‐unbound nucleus 109I. The lifetime value was determined using the Differential Decay‐Curve method in singles mode. The result has been compared to theoretical shell‐model calculations in order to better understand the nature of unbound valence nucleons at the proton drip line.

Published
2011
Full Text
View/download PDF

3. Measurement of absolute E2 transition strengths in [sup 176]W: Signatures for a rapid shape change

Author

Ch. Fransen, A. Dewald, G. Friessner, M. Hackstein, J. Jolie, O. Möller, T. Pissulla, W. Rother, K.-O. Zell, Paraskevi Demetriou, Rauno Julin, and Sotirios Harissopulos

Subjects
Nuclear physics, Phase transition, Recoil, Critical point (thermodynamics), Chemistry, Nuclear Theory, Nuclear structure, Neutron, Atomic physics, Interacting boson model, Nuclear Experiment, Axial symmetry, Oxygen-16
Abstract

The X(5) symmetry describes nuclei at the critical point of the shape phase transition from axially deformed rotor nuclei to spherical vibrators. 150Nd, 152Sm, and 154Gd were the first nuclei where the predicted charateristics of the X(5) symmetry were observed. Later it was shown that also 176,178,180Os can be successfully described with the X(5) symmetry.In the close vicinity of shape phase transitions one expects strongly changing nuclear shapes. In the X(5) region around A = 150 this was observed for nuclei with different neutron numbers, whereas in the X(5) region around A = 180 this is to be expected for different proton numbers. The aim of the work presented here is the confirmation of a rapid shape change for nuclei close to 178Os. Besides the knowledge on the level scheme of the nuclei of interest, especially absolute E2 transition strengths are crucial for the interpretation of nuclear structure. Prolate deformation is expected for 176W. Thus we performed a recoil distance Doppler shift (RDDS) m...

Published
2011
Full Text
View/download PDF

4. Lifetime measurements in light barium isotopes

Author

C. Michelagnoli, C. A. Ur, F. Brandolini, P. G. Bizzeti, A. M. Bizzeti-Sona, A. Giannatiempo, A. Nannini, P. Sona, D. Tonev, A. Dewald, D. Bazzacco, G. de Angelis, E. Farnea, C. Fransen, A. Gadea, S. Lenzi, S. Lunardi, B. Melon, R. Menegazzo, D. Mengoni, O. Möller, D. R. Napoli, P. Pavan, A. Perego, P. Petkov, C. M. Petrache, N. Pietralla, C. Rossi Alvarez, J. A. Caballero, C. E. Alonso, M. V. Andrés, J. E. García Ramos, and F. Pérez-Bernal

Subjects
Physics, Phase transition, Isotope, Degrees of freedom (physics and chemistry), chemistry.chemical_element, Barium, symbols.namesake, Recoil, chemistry, Quasiparticle, symbols, Atomic physics, Doppler effect, Radioactive decay
Abstract

The transition strenghts for the low—lying levels of 122,124Ba have been determined analysing the Recoil Distance Doppler Shift data by the Differential Decay Curve Method. The trend of normalised B(E2) reveals a drop in correspondance of the 81+ state. This feature is also present in 122Ba: entering the backbending region the interplay between collective and quasiparticle degrees of freedom have to be carefully taken into account.

Published
2010
Full Text
View/download PDF

5. Investigation of [sup 152]Sm by Complementary Reactions

Author

P. E. Garrett, W. D. Kulp, J. L. Wood, J. M. Allmond, D. Bandyopadhyay, S. Christen, S. N. Choudry, D. Cline, D. Dashdorj, A. Dewald, A. Fitzler, C. Fransen, A. B. Hayes, H. Hua, K. Jessen, J. Jolie, A. Kloezer, P. Kudejova, A. Kumar, S. R. Lesher, A. Linnemann, A. Lisetskiy, D. Martin, M. Masur, M. T. McEllistrem, O. Möller, M. G. Mynk, C. J. McKay, J. N. Orce, P. Pejovic, T. Pissulla, J.-M. Regis, A. Schiller, R. Teng, D. Tonev, C. Y. Wu, S. W. Yates, Jan Jolie, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Phase transition, Complementary experiments, Phonon, Critical point (thermodynamics), Chemistry, Excited state, Nuclear structure, Coulomb excitation, Atomic physics, Ground state
Abstract

Understanding the nuclear structure of 152Sm, along with other N = 90 isotones, has long posed a challenge. A rapid transition in shape between the spherical N = 88 150Sm and well‐deformed N = 92 154Sm is observed, along with strong evidence for shape coexistence. Competing ideas have been put forward over the decades, with the most recent being that N = 90 is at the critical point of a shape phase transition. Until recently, the lack of high‐precision data has not allowed the competing models to be extensively tested. In a coordinated program of investigation, a series of complementary experiments, which include high‐statistics β decay, multi‐step Coulomb excitation, the 150Nd(α,2n) reaction, and the (n,n′γ) reaction, have been performed for 152Sm. These experiments have revealed the existence of a pairing‐isomer band, a hexadecapole band, the lack of multi‐phonon β vibrational bands, and the repetition of structures built on the first excited Kπ = 0+ as built on the ground state. The status of these coo...

Published
2009
Full Text
View/download PDF

6. Transition probabilities in the X(5) candidate [sup 122]Ba

Author

P. G. Bizzeti, A. M. Bizzeti–Sona, D. Tonev, C. A. Ur, A. Dewald, A. Giannatiempo, B. Melon, D. Bazzacco, A. Costin, G. de Angelis, F. Della Vedova, M. Fantuzi, E. Farnea, C. Fransen, A. Gadea, S. M. Lenzi, S. Lunardi, N. Marginean, R. Marginean, R. Menegazzo, D. Mengoni, O. Möller, A. Nannini, D. R. Napoli, M. Nespolo, P. Pavan, A. Perego, P. Petkov, C. M. Petrache, N. Pietralla, C. Rossi Alvarez, Jan Jolie, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Physics, symbols.namesake, Recoil, Nucleosynthesis, Excited state, symbols, Neutron, Atomic physics, Doppler effect, Radioactive decay
Abstract

The lifetimes of excited states of the 122Ba ground—state band, populated via the 108Cd(16O,2n)122Ba and the 112Sn(13C,2n)122Ba reactions, have been measured using the Recoil Distance Doppler—Shift method. The level scheme of 122Ba has also been revised.

Published
2009
Full Text
View/download PDF

7. Collectivity of [sup 98]Pd

Author

C. Fransen, A. Blazhev, A. Dewald, J. Jolie, D. Mücher, O. Möller, T. Pissulla, Jan Jolie, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Physics, Nuclear physics, Recoil, Spectrometer, Angular correlation, Excited state, Yrast, Collective model, Tandem accelerator, Atomic physics, Spin (physics)
Abstract

The N = 52 nucleus 98Pd was investigated at the Cologne TANDEM accelerator both with the Cologne plunger using the recoil distance Doppler‐shift method (RDDS) and with the Cologne HORUS spectrometer for a γγ angular correlation experiment. For the first time lifetimes of yrast states and highly excited low‐spin states were measured in 98Pd and the low‐spin level scheme was extended. From our data we were able to interpret 98Pd as a nucleus that exhibits some collective features, but is obviously much less collective than the neighboring N = 52 isotones 94Mo and 96Ru due to its closeness to doubly‐magic 100Sn.

Published
2009
Full Text
View/download PDF

8. Nuclear structure analysis using the Orange Spectrometer

Author

J.-M. Régis, Gh. Pascovici, Th. Materna, S. Christen, T. Meersschout, C. Bernards, Ch. Fransen, A. Dewald, N. Braun, S. Heinze, S. Thiel, J. Jolie, Jan Jolie, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Beamline, Spectrometer, Chemistry, Analytical chemistry, Gamma spectroscopy, Electron, Atomic physics, Scintillator, Spectroscopy, Electron spectroscopy, Spectral line
Abstract

Recently, an Orange spectrometer, a focusing iron‐free magnetic spectrometer, has been installed at a beam line of the 10 MV Tandem accelerator of the IKP of the University of Cologne. The high efficiency of 15% of 4π for the detection of conversion electrons and the energy resolution of 1% makes the Orange spectrometer a powerful instrument. From the conversion electron spectrum, transition multipolarities can be determined using the so called K to L ratio. In combination with an array of germanium and lanthanum bromide detectors, e−‐γ‐coincidences can be performed to investigate the level scheme. Moreover, the very fast lanthanum bromide scintillator with an energy resolution of 3% allows e−‐γ lifetime measurements down to 0.3 ns. A second Orange spectrometer can be added to build the Double Orange Spectrometer for e−‐e−‐coincidences. It is indispensable for lifetime measurements of low intensity or nearby lying transitions as often occur in odd‐A and odd‐odd nuclei. The capabilities are illustrated wit...

Published
2009
Full Text
View/download PDF

9. Development of a new Recoil Distance Technique using Coulomb Excitation in Inverse Kinematics

Author

Wolfram Rother, Alfred Dewald, Gabriela Ilie, Thomas Pissulla, Barbara Melon, Jan Jolie, Gheorghe Pascovici, Hironori Iwasaki, Matthias Hackstein, Karl-Oskar Zell, Rauno Julin, Peter Jones, Paul Greenlees, Panu Rahkila, Juha Uusitalo, Cath Scholey, Sotirios Harissopulos, Anastasios Lagoyannis, Theodore Konstantinopoulos, Tuomas Grahn, Dimiter Balabanski, Pavel Petkov, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Nuclear physics, Plunger, Physics, Recoil, Spectrometer, Inverse kinematics, Excited state, Coulomb excitation, Kinematics, Beam (structure)
Abstract

We report on an experiment using Coulomb excitation in inverse kinematics in combination with the plunger technique for measuring lifetimes of excited states of the projectiles. Aside from the investigation of E(5) features in 128Xe, the aim was to explore the special features of such experiments which are also suited to be used with radioactive beams. The measurement was performed at the JYFL with the Koln coincidence plunger device and the JUROGAM spectrometer using a 128Xe beam impinging on a natFe target at a beam energy of 525 MeV. Recoils were detected by means of 32 solar cells placed at extreme forward angles. Particle‐gated γ‐singles and γγ‐coincidences were measured at different target‐degrader distances. Details of the experiment and first results are presented.

Published
2009
Full Text
View/download PDF

10. Plunger lifetime measurements after Coulomb excitation at intermediate beam energies

Author

A. Dewald, K. Starosta, P. Petkov, M. Hackstein, W. Rother, P. Adrich, A. M. Amthor, T. Baumann, D. Bazin, M. Bowen, A. Chester, A. Dunomes, A. Gade, D. Galaviz, T. Glasmacher, T. Ginter, M. Hausmann, J. Jolie, B. Melon, D. Miller, V. Moeller, R. P. Norris, T. Pissulla, M. Portillo, Y. Shimbara, A. Stolz, C. Vaman, P. Voss, D. Weisshaar, Jan Jolie, Andreas Zilges, Nigel Warr, and Andrey Blazhev

Subjects
Physics, symbols.namesake, Valence (chemistry), Recoil, Proton, Projectile, symbols, Neutron, Coulomb excitation, Atomic physics, Nuclear Experiment, Doppler effect, Particle detector
Abstract

Absolute transition probabilities of the first 2+ state in 110,114Pd were remeasured using the recoil distance Doppler shift technique following projectile Coulomb excitation at intermediate beam energies for the first time. The 110Pd experiment served to check the novel technique as well as the method used for the data analysis which is based on the examination of γ‐ray lineshapes. Whereas the measured B(E2) value for 110Pd agrees very well with the literature, the value obtained for 114Pd differs considerably. The data is also used to test a novel concept, called the valence proton symmetry, which allows one to extrapolate nuclear properties to very neutron rich nuclei.

Published
2009
Full Text
View/download PDF

11. Lifetime Measurements and Coulomb Excitation of Light Hg Nuclei

Author

A. Petts, P. A. Butler, T. Grahn, A. Blazhev, N. Bree, B. Bruyneel, J. Cederkäll, E. Clement, T. E. Cocolios, A. Dewald, J. Eberth, L. Fraile, C. Fransen, M. B. Gómez Hornillos, P. T. Greenlees, A. Görgen, M. Guttormsen, K. Hadynska, K. Helariutta, R.-D. Herzberg, M. Huyse, D. G. Jenkins, J. Jolie, P. Jones, R. Julin, S. Juutinen, S. Ketelhut, S. Knapen, T. Kröll, R. Krücken, A. C. Larsen, M. Leino, J. Ljungvall, P. Maierbeck, P. L. Marley, B. Melon, P. J. Napiorkowski, M. Nyman, R. D. Page, J. Pakarinen, G. Pascovici, N. Patronis, P. J. Peura, E. Piselli, Th. Pissulla, P. Rahkila, P. Reiter, J. Sarén, M. Scheck, C. Scholey, A. Semchenkov, S. Siem, I. Stefanescu, J. Sorri, J. Uusitalo, J. Van de Walle, P. Van Duppen, D. Voulot, R. Wadsworth, N. Warr, D. Weisshaar, F. Wenander, M. Zielinska, Jan Jolie, Andreas Zilges, Nigel Warr, Andrey Blazhev, Blazhev, A, Jolie, J, Warr, N, and Zilges, A

Subjects
Physics, Coulomb excitation, Yrast, shape coexistence, Hg, Preliminary analysis, Nuclear physics, symbols.namesake, Recoil, Nucleosynthesis, Recoil distance Doppler-shift, lifetimes, symbols, Atomic physics, Nuclear Experiment, Doppler effect, Radioactive decay
Abstract

Two complementary experimental programs have taken place to investigate the origin and evolution of shape coexistence in the light mercury region. Recoil Distance Doppler-shift measurements were performed at the University of Jyvaskyla utilizing the Koln plunger device in conjunction with the JUROGAM + RITU + GREAT setup. In addition, Coulomb excitation measurements of 184,186,188Hg were performed at REX-ISOLDE using the MINIBALL Ge-detector array. The results of the lifetime measurements of the yrast states up to I^{\pi} = 10+ in 182Hg are reported. Preliminary analysis of the Coulomb excitation data is also discussed. ispartof: pages:414-418 ispartof: AIP Conference Proceedings vol:1090 pages:414-418 ispartof: Capture gamma-ray spectroscopy and related topics location:Koln, Germany date:25 Aug - 28 Aug 2008 status: published

Published
2009
Full Text
View/download PDF

12. Probing collectivity in the vicinity of neutron deficient Pb nuclei

Author

T. Grahn, A. Dewald, M. B. Gómez Hornillos, P. T. Greenlees, A. Görgen, K. Helariutta, J. Jolie, P. Jones, R. Julin, S. Juutinen, S. Ketelhut, R. Krücken, T. Kröll, M. Leino, J. Ljungvall, P. Maierbeck, B. Melon, M. Nyman, R. D. Page, A. Petts, Th. Pissulla, P. Rahkila, J. Sarén, C. Scholey, J. Sorri, J. Uusitalo, R. Wadsworth, M. Zielińska, P. Demetriou, and S. V. Harissopulos

Subjects
Physics, Recoil, Excited state, Nuclear Theory, Oblate spheroid, Nuclear structure, Electromagnetic devices, Neutron, Prolate spheroid, Atomic physics, Nuclear Experiment
Abstract

A series of recoil distance Doppler‐shift lifetime measurements have been carried out to probe collectivity and configuration mixing of different shapes in the vicinity of neutron mid‐shell Pb nuclei. Lifetime measurements of 186Pb and 194Po, the first ever utilizing the recoil‐decay tagging method, probed the collectivity of coexisting prolate and oblate shapes in this region. Futher lifetime measurements of excited states in 180Hg, 182Hg and 196Po have been carried out.

Published
2008
Full Text
View/download PDF

13. 128Xe Lifetime Measurement Using the Coulex‐Plunger Technique in Inverse Kinematics

Author

R. Julin, D. L. Balabanski, P. Jones, Alfred Dewald, G. Ilie, S. Harissopulos, T. Grahn, T. Konstantinopoulos, P. Rakhila, P. T. Greenlees, A. Lagoyannis, and W. Rother

Subjects
Plunger, Physics, Recoil, Inverse kinematics, Spectrometer, Yrast, Kinematics, Coulomb excitation, Atomic physics, Nuclear Experiment, Beam (structure)
Abstract

The lifetimes of the lowest collective yrast and non‐yrast states in 128Xe were measured in a Coulomb excitation experiment using the recoil distance method (RDM) in inverse kinematics. Hereby, the Cologne plunger apparatus was employed together with the JUROGAM spectrometer. Excited states in 128Xe were populated using a 128Xe beam impinging on a natFe target with E(128Xe)≈525 MeV. Recoils were detected by means of an array of solar cells placed at forward angles. Recoil‐gated γ‐spectra were measured at different plunger distances.

Published
2008
Full Text
View/download PDF

14. Quantum Phase Transitions in Atomic Nuclei

Author

J. Jolie, A. Dewald, P. Demetriou, R. Julin, and S. V. Harissopulos

Subjects
Quantum phase transition, Physics, Phase transition, Condensed matter physics, Quantum critical point, Atomic nucleus, Nuclear structure, Interacting boson model, Critical point (mathematics), Boson
Abstract

During the last few years there has been considerable interest in nuclei located at the onset of deformation. From the theoretical side this onset of deformation can be described as a quantum phase transition. Here detailed studies using the interacting boson and the collective model have been performed. In the latter atomic nuclei located at the phase transition between spherical and deformed can be described using the critical point symmetries X(5) and E(5). We review recent experimental studies in the oblate‐prolate and sperical to deformed region which are looking for signatures of phase transitional behavior and/or critical point symmetries. We also discuss the difference between shape coexistence and these shape phase transitions.

Published
2008
Full Text
View/download PDF

15. Lifetime measurements using the CLARA-PRISMA setup around the [sup 48]Ca doubly-magic nucleus

Author

J. J. Valiente-Dobón, D. Mengoni, A. Gadea, E. Farnea, S. M. Lenzi, S. Lunardi, A. Dewald, T. Pissulla, S. Szilner, A. M. Stefanini, R. Broda, L. Angus, D. Bazzacco, G. Benzoni, P. G. Bizzeti, A. M. Bizzeti-Sona, P. Boutachkov, L. Corradi, F. Crespi, G. de Angelis, E. Fioretto, A. Görgen, M. Gorska, A. Gottardo, E. Grodner, A. Howard, W. Królas, S. Leoni, P. Mason, D. Montanari, G. Montagnoli, D. R. Napoli, A. Obertelli, T. Pawłat, F. Recchia, A. Algora, B. Rubio, E. Sahin, F. Scarlassara, J. F. Smith, D. Steppenbeck, C. A. Ur, P. T. Wady, J. Wrzesiński, Ismail Boztosun, and A. B. Balantekin

Subjects
Physics, Spectrometer, Nuclear Theory, Nuclear physics, symbols.namesake, Recoil, medicine.anatomical_structure, Excited state, medicine, symbols, MAGIC (telescope), Atomic physics, Nuclear Experiment, Nucleus, Doppler effect
Abstract

The lifetimes of the first excited states of nuclei around the doubly‐magic nucleus 48Ca have been determined using a novel method that combines the Recoil Distance Doppler Shift (RDDS) method with the CLARA‐PRISMA spectrometers. This is the first time such a method is applied to measure lifetimes of neutron‐rich nuclei populated via a multinucleon transfer reaction. This novel method and some preliminary results on lifetimes are presented.

Published
2008
Full Text
View/download PDF

16. Alpha-capture reactions relevant to the p-process nucleosynthesis

Author

C. Rolfs, R. Julin, Hans Werner Becker, P. von Brentano, Paraskevi Demetriou, A. Lagoyannis, Sotirios Harissopulos, K. O. Zell, A. Spyrou, A. Dewald, Frank Strieder, and Ch. Zarkadas

Subjects
Physics, Nuclear physics, Isotopes of germanium, Nucleosynthesis, Isotopes of tin, Coulomb barrier, Statistical model, Nuclear drip line, p-process, Calorimeter
Abstract

A systematic effort to measure (α, γ) cross sections for nuclei in the Ge‐Sn region and at energies below the Coulomb barrier is reported. Results of the measurements performed with a 4π calorimeter are presented. The data are compared with statistical model calculations and the impact of various nuclear inputs is discussed.

Published
2006
Full Text
View/download PDF

17. Plunger Lifetime Measurements in 102Pd

Author

A. Liennemann, A. Fitzler, C. A. Ur, M. Axiotis, A. Spyrou, D. Bazzacco, C. Rusu, R. Julin, B. Saha, G. Kalyva, R. Vlastou, E. Farnea, Sotirios Harissopulos, A. Dewald, D. R. Napoli, G. de Angelis, D. L. Balabanski, and N. Marginean

Subjects
Nuclear reaction, Nuclear physics, Plunger, Spectrometer, Chemistry, Isotopes of palladium, Nuclear structure, Isotopes of zirconium, Symmetry (physics), Excitation
Abstract

Recently, an intense experimental effort has been devoted to the search of empirical proofs of critical‐point symmetries in nuclear structure. These symmetries describe shape‐phase transitions and provide parameter‐free predictions (up to over‐all scale factors) for excitation spectra and B(E2) values. This contribution reports on recent plunger‐lifetime measurements ON 102Pd carried out at LNL, Legnaro, with the Cologne plunger apparatus coupled to the GASP spectrometer and using the 92Zr(13C,3n)102Pd reaction at 48 MeV. According to the results of our measurements, 102Pd is so far the best known paradigm of the E(5) critical‐point symmetry.

Published
2006
Full Text
View/download PDF

18. Two-Phonon Octupole Excitation in 146Gd

Author

A. Dewald, M. Piiparinen, A. Fitzler, J. Jolie, E. Nacher, L. Caballero, S. W. Yates, R. Julin, B. Rubio, O. Möller, A. Linnemann, A. Algora, Jan-Erik Blomqvist, S. Lunardi, P. Kleinheinz, R. Menegazzo, and A. Gadea

Subjects
Physics, Branching fraction, Phonon, Excited state, Yrast, Nuclear shell model, Neutron, Gamma spectroscopy, Atomic physics, Excitation
Abstract

The excited states in 146Gd have been re‐investigated with the 144Sm(α,2n) reaction using a modern Ge γ‐ray array including a polarimeter. Amongst the non‐yrast states populated in this reaction we have identified the aligned 6+ member of the two‐phonon octupole quartet from the observation of the E3 branching to the one phonon 3− state. Our results represent the first observation of a 6+→3−→0+ E3 cascade in an even‐even nucleus.

Published
2006
Full Text
View/download PDF

19. Tethering Carbon Nanotubes

Author

Madhuvanthi A. Kandadai, James Dewald, Donghui Zhang, Seamus A. Curran, and Aditya Avadhanula

Subjects
Materials science, Scanning electron microscope, Tethering, Atomic force microscopy, Analytical chemistry, Selective chemistry of single-walled nanotubes, Carbon nanotube, law.invention, Optical properties of carbon nanotubes, symbols.namesake, Chemical engineering, law, Covalent bond, symbols, Raman spectroscopy
Abstract

Using Phosphorous Pentasulphide a new single step electrophilic route has been achieved to link Multi‐Walled Carbon Nanotubes covalently through a dithioester linkage. Raman spectra of the tethered tubes was collected using the In Via Renishaw Raman Spectrometer. FESEM images and AFM height analysis were also obtained for the linked tubes.

Published
2005
Full Text
View/download PDF

20. Defect Analysis of Carbon Nanotubes

Author

Jamal A. Talla, James Dewald, Seamus A. Curran, and Tanja Pietrass

Subjects
inorganic chemicals, Materials science, technology, industry, and agriculture, Nanotechnology, macromolecular substances, Plasma, Carbon nanotube, law.invention, Optical properties of carbon nanotubes, symbols.namesake, law, symbols, Acid treatment, Raman spectroscopy
Abstract

Raman spectroscopic analysis of plasma treated MWNTs was used characterize defects in MWNTs. Raman spectroscopy was also used to characterize defects induced via acid treatment. The Raman‐active disorder modes are used to fingerprint PSF attachment to MWNTs via defect states.

Published
2005
Full Text
View/download PDF

21. NMR Spectroscopy of Hydrogen Adsorption on Carbon Nanotubes

Author

T. Pietraß, K. Shen, James Dewald, and Seamus A. Curran

Subjects
Materials science, Hydrogen, Resonance Raman spectroscopy, Analytical chemistry, Selective chemistry of single-walled nanotubes, chemistry.chemical_element, Carbon nanotube, Nuclear magnetic resonance spectroscopy, law.invention, Optical properties of carbon nanotubes, Condensed Matter::Materials Science, Hydrogen storage, chemistry, law, Physical chemistry, Physics::Chemical Physics, Spectroscopy
Abstract

Hydrogen storage properties of both single‐ and multi‐walled carbon nanotubes (CNTs) under pressures up to 15 MPa are studied by nuclear magnetic resonance (NMR) spectroscopy. The role of residual metallic catalyst in hydrogen adsorption is studied by comparing purified samples with parent materials. Structural features such as diameter and defect density are determined by resonance Raman spectroscopy.

Published
2005
Full Text
View/download PDF

22. Double and triple octupole excitations in the A≈150 region

Author

R. Krücken, H. Tiesler, D. R. Kasemann, D. Bazzacco, A. M. Bizzeti-Sona, A. Dewald, L. Bargioni, G. Maron, R. Peusquens, T. Klemme, C. Rossi Alvarez, M. De Poli, G. de Angelis, S. Lunardi, L. H. Zhu, T. Klug, P. G. Bizzeti, F. Banci Buonamici, D. R. Napoli, P. Pavan, C. M. Petrache, and Zs. Podolyák

Subjects
Nuclear physics, Physics, Nuclear structure, Gamma spectroscopy, Atomic physics, Excitation, Radioactive decay
Abstract

The results of recent experiments performed at L.N.L. on multiple octupole excitations in the N=84 isotones are reviewed. In particular, the results on B(E3) strengths in 146Sm are discussed and expectations for higher-order octupole excitations are compared with the present experimental situation.

Published
1999
Full Text
View/download PDF

23. The neuromodulatory properties of 'noisy neuronal oscillators'

Author

Karlheinz Voigt, Mathias Dewald, Hans A. Braun, and Martin T. Huber

Subjects
Membrane potential, Amplitude, Quantitative Biology::Neurons and Cognition, Control theory, Subthreshold membrane potential oscillations, Stochastic process, Oscillation, Depolarization, Impulse (physics), Biological system, Noise (electronics), Mathematics
Abstract

Many neurons, in various areas of the nervous system, exhibit spontaneous and intrinsic oscillations of their membrane potential or can develop oscillations on depolarization. Here we consider so-called subthreshold oscillations which operate close to the threshold of spike-generation. To analyze the principle neuromodulatory properties of such neuronal mechanisms we developed a computer model consisting of only a mnimal set of ironic conductances but which nevertheless attains subthreshold membrane potential oscillations of variable frequency and amplitude. With the addition of stochastic components, the oscillations generate typical impulse patterns which originate from a mixture of spike-triggering and subthreshold oscillations. The spiking probability thereby depends on the oscillation and noise parameters. According to the experimental data, the model can be tuned from complete silence to tonic firing with maximum sensitivity between these two extremes. Range and steepness of the activity and sensiti...

Published
1997
Full Text
View/download PDF

24. Lifetime Measurement of the 2[sub 1][sup +] state in [sup 20]C

Author

Petri, M., primary, Fallon, P., additional, Macchiavelli, A. O., additional, Paschalis, S., additional, Starosta, K., additional, Baugher, T., additional, Bazin, D., additional, Cartegni, L., additional, Clark, R. M., additional, Crawford, H. L., additional, Cromaz, M., additional, Dewald, A., additional, Gade, A., additional, Grinyer, G. F., additional, Gros, S., additional, Hackstein, M., additional, Jeppesen, H. B., additional, Lee, I. Y., additional, McDaniel, S., additional, Miller, D., additional, Rajabali, M. M., additional, Ratkiewicz, A., additional, Rother, W., additional, Voss, P., additional, Walsh, K. A., additional, Weisshaar, D., additional, Wiedeking, M., additional, Demetriou, Paraskevi, additional, Julin, Rauno, additional, and Harissopulos, Sotirios, additional

Published
2011
Full Text
View/download PDF

26. Lifetime measurements in light barium isotopes

Author

Michelagnoli, C., primary, Ur, C. A., additional, Brandolini, F., additional, Bizzeti, P. G., additional, Bizzeti-Sona, A. M., additional, Giannatiempo, A., additional, Nannini, A., additional, Sona, P., additional, Tonev, D., additional, Dewald, A., additional, Bazzacco, D., additional, de Angelis, G., additional, Farnea, E., additional, Fransen, C., additional, Gadea, A., additional, Lenzi, S., additional, Lunardi, S., additional, Melon, B., additional, Menegazzo, R., additional, Mengoni, D., additional, Möller, O., additional, Napoli, D. R., additional, Pavan, P., additional, Perego, A., additional, Petkov, P., additional, Petrache, C. M., additional, Pietralla, N., additional, Rossi Alvarez, C., additional, Caballero, J. A., additional, Alonso, C. E., additional, Andrés, M. V., additional, García Ramos, J. E., additional, and Pérez-Bernal, F., additional

Published
2010
Full Text
View/download PDF

27. Nuclear structure analysis using the Orange Spectrometer

Author

Régis, J.-M., primary, Pascovici, Gh., additional, Materna, Th., additional, Christen, S., additional, Meersschout, T., additional, Bernards, C., additional, Fransen, Ch., additional, Dewald, A., additional, Braun, N., additional, Heinze, S., additional, Thiel, S., additional, Jolie, J., additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

28. Transition probabilities in the X(5) candidate [sup 122]Ba

Author

Bizzeti, P. G., primary, Bizzeti–Sona, A. M., additional, Tonev, D., additional, Ur, C. A., additional, Dewald, A., additional, Giannatiempo, A., additional, Melon, B., additional, Bazzacco, D., additional, Costin, A., additional, de Angelis, G., additional, Vedova, F. Della, additional, Fantuzi, M., additional, Farnea, E., additional, Fransen, C., additional, Gadea, A., additional, Lenzi, S. M., additional, Lunardi, S., additional, Marginean, N., additional, Marginean, R., additional, Menegazzo, R., additional, Mengoni, D., additional, Möller, O., additional, Nannini, A., additional, Napoli, D. R., additional, Nespolo, M., additional, Pavan, P., additional, Perego, A., additional, Petkov, P., additional, Petrache, C. M., additional, Pietralla, N., additional, Alvarez, C. Rossi, additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

29. Investigation of [sup 152]Sm by Complementary Reactions

Author

Garrett, P. E., primary, Kulp, W. D., additional, Wood, J. L., additional, Allmond, J. M., additional, Bandyopadhyay, D., additional, Christen, S., additional, Choudry, S. N., additional, Cline, D., additional, Dashdorj, D., additional, Dewald, A., additional, Fitzler, A., additional, Fransen, C., additional, Hayes, A. B., additional, Hua, H., additional, Jessen, K., additional, Jolie, J., additional, Kloezer, A., additional, Kudejova, P., additional, Kumar, A., additional, Lesher, S. R., additional, Linnemann, A., additional, Lisetskiy, A., additional, Martin, D., additional, Masur, M., additional, McEllistrem, M. T., additional, Möller, O., additional, Mynk, M. G., additional, McKay, C. J., additional, Orce, J. N., additional, Pejovic, P., additional, Pissulla, T., additional, Regis, J.-M., additional, Schiller, A., additional, Teng, R., additional, Tonev, D., additional, Wu, C. Y., additional, Yates, S. W., additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

30. Plunger lifetime measurements after Coulomb excitation at intermediate beam energies

Author

Dewald, A., primary, Starosta, K., additional, Petkov, P., additional, Hackstein, M., additional, Rother, W., additional, Adrich, P., additional, Amthor, A. M., additional, Baumann, T., additional, Bazin, D., additional, Bowen, M., additional, Chester, A., additional, Dunomes, A., additional, Gade, A., additional, Galaviz, D., additional, Glasmacher, T., additional, Ginter, T., additional, Hausmann, M., additional, Jolie, J., additional, Melon, B., additional, Miller, D., additional, Moeller, V., additional, Norris, R. P., additional, Pissulla, T., additional, Portillo, M., additional, Shimbara, Y., additional, Stolz, A., additional, Vaman, C., additional, Voss, P., additional, Weisshaar, D., additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

31. Collectivity of [sup 98]Pd

Author

Fransen, C., primary, Blazhev, A., additional, Dewald, A., additional, Jolie, J., additional, Mücher, D., additional, Möller, O., additional, Pissulla, T., additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

32. Lifetime Measurements and Coulomb Excitation of Light Hg Nuclei

Author

Petts, A., primary, Butler, P. A., additional, Grahn, T., additional, Blazhev, A., additional, Bree, N., additional, Bruyneel, B., additional, Cederkäll, J., additional, Clement, E., additional, Cocolios, T. E., additional, Dewald, A., additional, Eberth, J., additional, Fraile, L., additional, Fransen, C., additional, Hornillos, M. B. Gómez, additional, Greenlees, P. T., additional, Görgen, A., additional, Guttormsen, M., additional, Hadynska, K., additional, Helariutta, K., additional, Herzberg, R.-D., additional, Huyse, M., additional, Jenkins, D. G., additional, Jolie, J., additional, Jones, P., additional, Julin, R., additional, Juutinen, S., additional, Ketelhut, S., additional, Knapen, S., additional, Kröll, T., additional, Krücken, R., additional, Larsen, A. C., additional, Leino, M., additional, Ljungvall, J., additional, Maierbeck, P., additional, Marley, P. L., additional, Melon, B., additional, Napiorkowski, P. J., additional, Nyman, M., additional, Page, R. D., additional, Pakarinen, J., additional, Pascovici, G., additional, Patronis, N., additional, Peura, P. J., additional, Piselli, E., additional, Pissulla, Th., additional, Rahkila, P., additional, Reiter, P., additional, Sarén, J., additional, Scheck, M., additional, Scholey, C., additional, Semchenkov, A., additional, Siem, S., additional, Stefanescu, I., additional, Sorri, J., additional, Uusitalo, J., additional, Van de Walle, J., additional, Van Duppen, P., additional, Voulot, D., additional, Wadsworth, R., additional, Warr, N., additional, Weisshaar, D., additional, Wenander, F., additional, Zielinska, M., additional, Jolie, Jan, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

33. Development of a new Recoil Distance Technique using Coulomb Excitation in Inverse Kinematics

Author

Rother, Wolfram, primary, Dewald, Alfred, additional, Ilie, Gabriela, additional, Pissulla, Thomas, additional, Melon, Barbara, additional, Jolie, Jan, additional, Pascovici, Gheorghe, additional, Iwasaki, Hironori, additional, Hackstein, Matthias, additional, Zell, Karl-Oskar, additional, Julin, Rauno, additional, Jones, Peter, additional, Greenlees, Paul, additional, Rahkila, Panu, additional, Uusitalo, Juha, additional, Scholey, Cath, additional, Harissopulos, Sotirios, additional, Lagoyannis, Anastasios, additional, Konstantinopoulos, Theodore, additional, Grahn, Tuomas, additional, Balabanski, Dimiter, additional, Petkov, Pavel, additional, Zilges, Andreas, additional, Warr, Nigel, additional, and Blazhev, Andrey, additional

Published
2009
Full Text
View/download PDF

34. Probing collectivity in the vicinity of neutron deficient Pb nuclei

Author

Grahn, T., primary, Dewald, A., additional, Hornillos, M. B. Gómez, additional, Greenlees, P. T., additional, Görgen, A., additional, Helariutta, K., additional, Jolie, J., additional, Jones, P., additional, Julin, R., additional, Juutinen, S., additional, Ketelhut, S., additional, Krücken, R., additional, Kröll, T., additional, Leino, M., additional, Ljungvall, J., additional, Maierbeck, P., additional, Melon, B., additional, Nyman, M., additional, Page, R. D., additional, Petts, A., additional, Pissulla, Th., additional, Rahkila, P., additional, Sarén, J., additional, Scholey, C., additional, Sorri, J., additional, Uusitalo, J., additional, Wadsworth, R., additional, Zielińska, M., additional, Demetriou, P., additional, and Harissopulos, S. V., additional

Published
2008
Full Text
View/download PDF

36. Lifetime measurements using the CLARA-PRISMA setup around the [sup 48]Ca doubly-magic nucleus.

Author

Valiente-Dobón, J. J., primary, Mengoni, D., additional, Gadea, A., additional, Farnea, E., additional, Lenzi, S. M., additional, Lunardi, S., additional, Dewald, A., additional, Pissulla, T., additional, Szilner, S., additional, Stefanini, A. M., additional, Broda, R., additional, Angus, L., additional, Bazzacco, D., additional, Benzoni, G., additional, Bizzeti, P. G., additional, Bizzeti-Sona, A. M., additional, Boutachkov, P., additional, Corradi, L., additional, Crespi, F., additional, de Angelis, G., additional, Fioretto, E., additional, Görgen, A., additional, Gorska, M., additional, Gottardo, A., additional, Grodner, E., additional, Howard, A., additional, Królas, W., additional, Leoni, S., additional, Mason, P., additional, Montanari, D., additional, Montagnoli, G., additional, Napoli, D. R., additional, Obertelli, A., additional, Pawłat, T., additional, Recchia, F., additional, Algora, A., additional, Rubio, B., additional, Sahin, E., additional, Scarlassara, F., additional, Smith, J. F., additional, Steppenbeck, D., additional, Ur, C. A., additional, Wady, P. T., additional, Wrzesiński, J., additional, Boztosun, Ismail, additional, and Balantekin, A. B., additional

Published
2008
Full Text
View/download PDF

39. Lifetime measurement in the proton-unbound nucleus 109I.

Author

Procter, M. G., Cullen, D. M., Ruotsalainen, P., Scholey, C., Angus, L., Bäck, T., Cederwall, B., Dewald, A., Fransen, C., Grahn, T., Greenlees, P. T., Hackstein, M., Jakobsson, U., Jones, P. M., Julin, R., Juutinen, S., Ketelhut, S., Leino, M., Lumley, N. M., and Mason, P. J. R.

Subjects
IODINE isotopes, PROTON decay, DOPPLER effect, NUCLEAR shell theory, PARTICLES (Nuclear physics), NUCLEAR physics
Abstract

The Recoil-Distance Doppler-shift method has been combined with Recoil-Decay Tagging for the first time to measure a lifetime in the proton-unbound nucleus 109I. The lifetime value was determined using the Differential Decay-Curve method in singles mode. The result has been compared to theoretical shell-model calculations in order to better understand the nature of unbound valence nucleons at the proton drip line. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

40. Neutron-Rich 62,64,64Fe Show Enhanced Collectivity: The Washout of N = 40 in Terms of Experiment, Valence Proton Symmetry and Shell Model.

Author

Rother, W., Dewald, A., Iwasaki, H., Lenzi, S. M., Starosta, K., Bazin, D., Baugher, T., Brown, B. A., Crawford, H. L., Fransen, C., Gade, A., Ginter, T. N., Glasmacher, T., Grinyer, G. F., Hackstein, M., Ilie, G., Jolie, J., McDaniel, S., Miller, D., and Petkov, P.

Subjects
*NEUTRONS, *IRON isotopes, *PHYSICS experiments, *PROTONS, *SYMMETRY (Physics), *NUCLEAR shell theory, *DOPPLER effect, *RADIOACTIVE nuclear beams
Abstract

Probing shell structure at a large neutron excess has been of particular interest in recent times. Neutron-rich nuclei between the proton shell closures Z = 20 and Z = 28 offer an exotic testing ground for shell evolution. The development of the N = 40 gap between neutron fp and lg9/2 shells gives rise to highly interesting variations of collectivity for nuclei in this region. While 68Ni shows doubly magic properties in level energies and transition strengths, this was not observed in neighbouring nuclei. Especially neutron-rich Fe isotopes proved particularly resistant to calculational approaches using the canonical valence space (fpg) resulting in important deviations of the predicted collectivity. Only an inclusion of the d5/2-orbital could solve the problem [1]. Hitherto no transition strengths for 66Fe have been reported. We determined B(E2,2+1→0+1) values from lifetimes measured with the recoil distance Doppler-shift method using the Cologne plunger for radioactive beams at National Superconducting Cyclotron Laboratory at Michigan State University. Excited states were populated by projectile Coulomb excitation for 62,64,66Fe. The data show a rise in collectivity for Fe isotopes towards N = 40. Results [2] are interpreted by means of a modified version of the Valence Proton Symmetry [3] and compared to shell model calculations using a new effective interaction recently developed for the fpgd valence space [4]. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

41. Measurement of absolute E2 transition strengths in 176W: Signatures for a rapid shape change.

Author

Fransen, Ch., Dewald, A., Friessner, G., Hackstein, M., Jolie, J., Möller, O., Pissulla, T., Rother, W., and Zell, K.-O.

Subjects
*SYMMETRY (Physics), *PHASE transitions, *CRITICAL point (Thermodynamics), *PROTONS, *PARTICLES (Nuclear physics), *NUCLEAR structure, *PHYSICS experiments
Abstract

The X(5) symmetry describes nuclei at the critical point of the shape phase transition from axially deformed rotor nuclei to spherical vibrators. 150Nd, 152Sm, and 154Gd were the first nuclei where the predicted charateristics of the X(5) symmetry were observed. Later it was shown that also 176,178,180Os can be successfully described with the X(5) symmetry. In the close vicinity of shape phase transitions one expects strongly changing nuclear shapes. In the X(5) region around A = 150 this was observed for nuclei with different neutron numbers, whereas in the X(5) region around A = 180 this is to be expected for different proton numbers. The aim of the work presented here is the confirmation of a rapid shape change for nuclei close to 178Os. Besides the knowledge on the level scheme of the nuclei of interest, especially absolute E2 transition strengths are crucial for the interpretation of nuclear structure. Prolate deformation is expected for 176W. Thus we performed a recoil distance Doppler shift (RDDS) measurement on 176W to measure E2 transition strengths from level lifetimes. The experiment was performed at the Cologne FN TANDEM accelerator with the Cologne coincidence plunger with the reaction 169Dy(16O,4n)176W and a beam energy of 80 MeV. We will present our experimental results and relate them to data on the neighboring nuclei 178Os and 182Pt. The results will be discussed in the framework of nuclear shape transitions in this mass region and compared to calculations with both the Interacting Boson Model (IBM) and the GCM. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

42. Lifetime Measurement of the 21+ state in 20C.

Author

Petri, M., Fallon, P., Macchiavelli, A. O., Paschalis, S., Starosta, K., Baugher, T., Bazin, D., Cartegni, L., Clark, R. M., Crawford, H. L., Cromaz, M., Dewald, A., Gade, A., Grinyer, G. F., Gros, S., Hackstein, M., Jeppesen, H. B., Lee, I. Y., McDaniel, S., and Miller, D.

Subjects
NUCLIDES, RADIOACTIVE nuclear beams, NUCLEAR reactions, NUCLEAR shell theory, ISOBARIC spin, NUCLEAR charge, PHYSICAL measurements
Abstract

The mean lifetime of the 21+ state in the near drip-line nuclide 20C was measured for the first time using the Recoil Distance Method with intermediate energy radioactive beams via a knockout reaction. The measured value of τ21+ = 9.8±2.8(stat)-1.1+0.5(syst) ps gives a reduced transition probability of B(E2;21+→0g.s.+) = 7.51.7+3.0(stat) e2fm4. This value is in good agreement with shell model calculations using a p-sd shell model space and isospin-dependent (N-Z) effective charges. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

43. Transition probabilities in the X(5) candidate 122Ba.

Author

Bizzeti, P. G., Bizzeti-Sona, A. M., Tonev, D., Ur, C. A., Dewald, A., Giannatiempo, A., Melon, B., Bazzacco, D., Costin, A., de Angelis, G., Vedova, F. Della, Fantuzi, M., Farnea, E., Fransen, C., Gadea, A., Lenzi, S. M., Lunardi, S., Marginean, N., Marginean, R., and Menegazzo, R.

Subjects
BARIUM, ISOTOPES, SAMARIUM, PHASE transitions, NUCLEAR physics, SPECTRUM analysis
Abstract

The lifetimes of excited states of the 122Ba ground—state band, populated via the 108Cd(16O,2n)122Ba and the 112Sn(13C,2n)122Ba reactions, have been measured using the Recoil Distance Doppler—Shift method. The level scheme of 122Ba has also been revised. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

44. Collectivity of 98Pd.

Author

Fransen, C., Blazhev, A., Dewald, A., Jolie, J., Mücher, D., Möller, O., and Pissulla, T.

Subjects
ISOTONE shift, ELECTRON-nucleus scattering, NUCLEAR reactions, SPIN excitations, PARTICLE accelerators, ANGULAR momentum (Nuclear physics)
Abstract

The N = 52 nucleus 98Pd was investigated at the Cologne TANDEM accelerator both with the Cologne plunger using the recoil distance Doppler-shift method (RDDS) and with the Cologne HORUS spectrometer for a γγ angular correlation experiment. For the first time lifetimes of yrast states and highly excited low-spin states were measured in 98Pd and the low-spin level scheme was extended. From our data we were able to interpret 98Pd as a nucleus that exhibits some collective features, but is obviously much less collective than the neighboring N = 52 isotones 94Mo and 96Ru due to its closeness to doubly-magic 100Sn. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

45. Investigation of 152Sm by Complementary Reactions.

Author

Garrett, P. E., Kulp, W. D., Wood, J. L., Allmond, J. M., Bandyopadhyay, D., Christen, S., Choudry, S. N., Cline, D., Dashdorj, D., Dewald, A., Fitzler, A., Fransen, C., Hayes, A. B., Hua, H., Jessen, K., Jolie, J., Kloezer, A., Kudejova, P., Kumar, A., and Lesher, S. R.

Subjects
NUCLEAR structure, ISOTOPES, PHASE transitions, COULOMB excitation, PHONONS, NUCLEAR isomers
Abstract

Understanding the nuclear structure of 152Sm, along with other N = 90 isotones, has long posed a challenge. A rapid transition in shape between the spherical N = 88 150Sm and well-deformed N = 92 154Sm is observed, along with strong evidence for shape coexistence. Competing ideas have been put forward over the decades, with the most recent being that N = 90 is at the critical point of a shape phase transition. Until recently, the lack of high-precision data has not allowed the competing models to be extensively tested. In a coordinated program of investigation, a series of complementary experiments, which include high-statistics β decay, multi-step Coulomb excitation, the 150Nd(α,2n) reaction, and the (n,n′γ) reaction, have been performed for 152Sm. These experiments have revealed the existence of a pairing-isomer band, a hexadecapole band, the lack of multi-phonon β vibrational bands, and the repetition of structures built on the first excited Kπ = 0+ as built on the ground state. The status of these coordinated studies is examined. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

46. Lifetime measurements using the CLARA-PRISMA setup around the 48Ca doubly-magic nucleus.

Author

Valiente-Dobón, J. J., Mengoni, D., Gadea, A., Farnea, E., Lenzi, S. M., Lunardi, S., Dewald, A., Pissulla, T., Szilner, S., Stefanini, A. M., Broda, R., Angus, L., Bazzacco, D., Benzoni, G., Bizzeti, P. G., Bizzeti-Sona, A. M., Boutachkov, P., Corradi, L., Crespi, F., and de Angelis, G.

Subjects
EXOTIC nuclei, SPECTRUM analysis instruments, DOPPLER effect, SPECTROMETERS, PARTICLES (Nuclear physics)
Abstract

The lifetimes of the first excited states of nuclei around the doubly-magic nucleus 48Ca have been determined using a novel method that combines the Recoil Distance Doppler Shift (RDDS) method with the CLARA-PRISMA spectrometers. This is the first time such a method is applied to measure lifetimes of neutron-rich nuclei populated via a multinucleon transfer reaction. This novel method and some preliminary results on lifetimes are presented. [ABSTRACT FROM AUTHOR]

Published
2008
Full Text
View/download PDF

47. Test of the critical point symmetry X(5) in neutron deficient osmium isotopes at A≈180.

Author

Dewald, A., Möller, O., Melon, B., Pissulla, T., Saha, B., Heinze, S., Jolie, J., Zell, K. O., Petkov, P., Bazzacco, D., Lunardi, S., Ur, C. A., Farnea, E., Menegazzo, R., De Angelis, G., Tonev, D., Napoli, D. R., Marginean, N., Martinez, T., and Axiotis, M.

Subjects
*NEUTRONS, *PARTICLES (Nuclear physics), *OSMIUM isotopes, *OSMIUM, *NUCLEAR physics, *PHYSICS
Abstract

The energy spectra and relative transition rates of 176,178,180Os were found to be very similar to the values calculated in the framework of the critical point symmetry X(5). In order to enable more stringent tests, including also absolute transition probabilities, two coincidence RDDS lifetime measurements were performed at the Laboratori Nazionali di Legnaro with the GASP spectrometer using the 152,154Sm(29Si,5n)176,178Os reactions. The deduced transition quadrupole moments in 178Os agree well with the X(5) predictions. For 176Os only preliminary results were obtained so far. These preliminary data support an X(5) like structure also in the case of 176Os. The experimental data of both nuclei are compared to calculations in the framework of the interacting boson model (IBM) and of the general collective model (GCM). © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
Full Text
View/download PDF

48. Two-Phonon Octupole Excitation in 146Gd.

Author

Caballero, L., Kleinheinz, P., Rubio, B., Algora, A., Blomqvist, J., Dewald, A., Fitzler, A., Gadea, A., Jolie, J., Julin, R., Linnemann, A., Lunardi, S., Menegazzo, R., Möller, O., Nácher, E., Piiparinen, M., and Yates, S. W.

Subjects
PHONONS, QUASIPARTICLES, GADOLINIUM, SAMARIUM, NUCLEAR physics, PHYSICS
Abstract

The excited states in 146Gd have been re-investigated with the 144Sm(α,2n) reaction using a modern Ge γ-ray array including a polarimeter. Amongst the non-yrast states populated in this reaction we have identified the aligned 6+ member of the two-phonon octupole quartet from the observation of the E3 branching to the one phonon 3- state. Our results represent the first observation of a 6+→3-→0+ E3 cascade in an even-even nucleus. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
Full Text
View/download PDF

49. Alpha-capture reactions relevant to the p-process nucleosynthesis.

Author

Spyrou, A., Lagoyannis, A., Zarkadas, Ch., Demetriou, P., Harissopulos, S., Becker, H.-W., Strieder, F., Rolfs, C., Dewald, A., Zell, K.-O., von Brentano, P., and Julin, R.

Subjects
GERMANIUM, COLLISIONS (Nuclear physics), COLLISIONS (Physics), NUCLEAR physics, PHYSICS, NUCLEOSYNTHESIS, TIN
Abstract

A systematic effort to measure (α, γ) cross sections for nuclei in the Ge-Sn region and at energies below the Coulomb barrier is reported. Results of the measurements performed with a 4π calorimeter are presented. The data are compared with statistical model calculations and the impact of various nuclear inputs is discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
Full Text
View/download PDF

50. Shape Coexistence in Light Krypton Isotopes.

Author

Görgen, A., Clément, E., Bouchez, E., Chatillon, A., Korten, W., Le Coz, Y., Theisen, Ch., Wilson, J. N., Andreoiu, C., Becker, F., Casandjian, J. M., Dewald, A., de France, G., Gerl, J., Iwanicki, J., Mǎginean, N., Melon, B., Menegazzo, R., Möller, O., and Sletten, G.

Subjects
ISOTOPES, KRYPTON, COULOMB excitation, NUCLEAR excitation, NUCLEAR shapes, NUCLEAR physics
Abstract

Coexisting states of prolate and oblate shapes were studied via Coulomb excitation of radioactive 74Kr and 76Kr beams at safe energies at GANIL. The results for the transitional E2 matrix elements for several yrast transitions in both isotopes are in contradiction with the B(E2) values extracted from the lifetimes that are found in the literature. This motivated a new lifetime measurement which showed strong deviations from the previously published values, but is consistent with the results from Coulomb excitation. Having resolved these discrepancies and knowing the B(E2) values with high precision allows to extract the diagonal matrix elements from the Coulomb excitation data. The results confirm the proposed shape coexistence scenario. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results