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45 results on '"Dracoulis, G. D."'

1. Properties of 187Ta revealed through isomeric decay

Author

Walker, P. M., Hirayama, Y., Lane, G. J., Watanabe, H., Dracoulis, G. D., Ahmed, M., Brunet, M., Hashimoto, T., Ishizawa, S., Kondev, F. G., Litvinov, Yu. A., Miyatake, H., Moon, J. Y., Mukai, M., Niwase, T., Park, J. H., Podolyak, Zs., Rosenbusch, M., Schury, P., Wada, M., Watanabe, X. Y., Liang, W. Y., and Xu, F. R.

Subjects
Physics::Atomic and Molecular Clusters, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Mass-separated 187Ta in a high-spin isomeric state has been produced for the first time by multi-nucleon transfer reactions, employing an argon gas stopping cell and laser ionisation. Internal gamma rays revealed a 7.3 s isomer at 1778 keV, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer decay reduced E2 hindrance factor of 27 supports the interpretation that axial symmetry is approximately conserved., 5 pages, 5 figures

Published
2020

2. High-spin yrast structure of $^{204}$Hg from the decay of a four-hole, $22^+$ isomer

Author

Wrzesiński, J., Lane, G. J., Maier, K. H., Janssens, R. V. F., Dracoulis, G. D., Broda, R., Byrne, A. P., Carpenter, M. P., Clark, R. M., Cromaz, M., Fornal, B., Lauritsen, T., Macchiavelli, A. O., Rejmund, M., Szpak, B., Vetter, K., Zhu, S., Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
21.10.Tg, 21.60.Cs, 23.20.Lv, 27.80.+w, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; A high-spin isomer with τ>700 ns has been found in Hg204, populated in reactions of 1360-MeV Pb208 and 330-MeV Ca48 beams with a thick U238 target and a 1450-MeV Pb208 beam on a thick Pb208 target. The observed γ-ray decay of the isomer has established the yrast states below it, including another isomer with τ=33(3) ns. The experimental results are compared with shell-model calculations that include four holes in the configuration space between Sn132 and Pb208. The available spectroscopic information, including transition strengths, total conversion, and angular correlation coefficients, together with the observed agreement with the calculations, allows spin, parity, and configuration assignments to be proposed for the experimental states. The τ>700 ns isomer is the 22+ state of maximum spin available from the alignment of the four valence holes with the configuration πh−211/2νi−213/2.

Published
2015
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3. Increased lifetime of hydrogen-like $^{192m}Os$ observed in the ESR

Author

Akber, A., Reed, M. W., Deo, A. Y., Detwiler, B., Dimopoulou, C., Dracoulis, G. D., Farinon, F., Geissel, H., Haettner, E., Heil, M., Kempley, R. S., Kibedi, T., Walker, P. M., Knöbel, R., Kozhuharov, C., Kurcewicz, J., Kuzminchuk, N., Lane, G. J., Litvinov, S., Liu, Z., Mao, R., Nociforo, C., Nolden, F., Cullen, I. J., Plaß, Wolfgang, Prochazka, A., Scheidenberger, C., Shubina, D., Steck, M., Stöhlker, T., Sun, B., Swan, T. P. D., Trees, G., Weick, H., Litvinov, Yury, Winckler, N., Winkler, M., Woods, P. J., Yamaguchi, T., Blaum, K., Bosch, F., Brandau, C., Carroll, J. J., and Cullen, D. M.

Subjects
Physics
Abstract

GSI Scientific Report 2013 - GSI Report 2014-1

Published
2014
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4. Multiple beta(-) decaying states in Re-194: Shape evolution in neutron-rich osmium isotopes

Author

Al-Dahan, N., Regan, P. H., Podolyak, Zs., Walker, P. M., Alkhomashi, N., Dracoulis, G. D., Farrelly, G., Benlliure, J., Pietri, S. B., Casten, R. F., Stevenson, P. D., Gelletly, W., Steer, S. J., Garnsworthy, A. B., Casarejos, E., Gerl, J., Wollersheim, H. J., Grebosz, J., Gorska, M., Kojouharov, I., Schaffner, H., Algora, A., Benzoni, G., Blazhev, A., Boutachkov, P., Bruce, A. M., Cullen, I. J., Bacelar, A. M. Denis, Deo, A. Y., Estevez, M. E., Fujita, Y., Hoischen, Robert, Kumar, R., Lalkovski, S., Liu, Z., Mason, P. J., Mihai, C., Molina, F., Muecher, D., Rubio, B., Tamii, A., Tashenov, S., Valiente-Dobon, J. J., and Woods, P. J.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Subatomic Physics, Nuclear Experiment
Abstract

beta decays from heavy, neutron-rich nuclei with A similar to 190 have been investigated following their production via the relativistic projectile fragmentation of an E/A = 1 GeV Pb-208 primary beam on a similar to 2.5 g/cm(2) Be-9 target. The reaction products were separated and identified using the GSI FRagment Separator (FRS) and stopped in the RISING active stopper. gamma decays were observed and correlated with these secondary ions on an event-by-event basis such that gamma-ray transitions following from both internal (isomeric) and beta decays were recorded. A number of discrete, beta-delayed gamma-ray transitions associated with beta decays from Re-194 to excited states in Os-194 have been observed, including previously reported decays from the yrast I-pi = (6(+)) state. Three previously unreported gamma-ray transitions with energies 194, 349, and 554 keV are also identified; these transitions are associated with decays from higher spin states in Os-194. The results of these investigations are compared with theoretical predictions from Nilsson multi-quasiparticle (MQP) calculations. Based on lifetime measurements and the observed feeding pattern to states in Os-194, it is concluded that there are three beta(-)-decaying states in Re-194.

Published
2012

5. High-spin, multiparticle isomers in (121,123)Sb

Author

Jones, G. A., Williams, S. J., Walker, P. M., Podolyák, Zs., Zhu, S., Carpenter, M. P., Carroll, J. J., Chakrawarthy, R. S., Chowdhury, P., Cullen, I. J., Dracoulis, G. D., Garnsworthy, A. B., Hackman, G., Janssens, R. V. F., Khoo, T. L., Kondev, F. G., Lane, G. J., Liu, Z., Seweryniak, D., and Thompson, N. J.

Published
2008

6. High-Spin, Multiparticle Isomers in Sb-121,Sb-123

Author

Jones, G A, Williams, S J, Walker, P M, Podolyak, Z, Zhu, S, Carpenter, M P, Carroll, J J, Chakrawarthy, R S, Chowdhury, P, Cullen, I J, Dracoulis, G D, Garnsworthy, A B, Hackman, G, Janssens, R V, Khoo, T L, Kondev, F G, Lane, G J, Liu, Z, Seweryniak, D, and Thompson, N J

Abstract

Isomers in near-spherical Z = 51, antimony isotopes are reported here for the first time using fusion-fission reactions between Al-27 and a pulsed Hf-178 beam of energy, 1150 MeV. gamma rays were observed from the decay of isomeric states with half-lives, T-1/2 = 200(30) and 52(3) mu s, and angular momenta I = (25/2) and I-pi = 23(+)/2, in Sb-121,Sb-123, respectively. These states are proposed to correspond to nu(h(11/2))(2) configurations, coupled to an odd d(5/2) or g(7/2) proton. Nanosecond isomers were also identified at I-pi = 19(-)/2 [T-1/2 = 8.5(5) ns] in Sb-121 and I-pi = (15(-)/2) [T-1/2 = 37(4) ns] in Sb-123. Information on spins and parities of states in these nuclei was obtained using a combination of angular correlation and intensity-balance measurements. The configurations of states in these nuclei are discussed using a combination of spin/energy systematics and shell-model calculations for neighboring tin isotones and antimony isotopes.

Published
2008

7. Measurement of conversion electrons with the $^{208}Pb(p,n)^{208}Bi$ reaction and derivation of the shell model proton neutron hole interaction from the properties of $^{208}Bi$

Author

Maier, K H, Kibédi, T, Dracoulis, G D, Boutachkov, P, Aprahamian, A, Byrne, A P, Davidson, P M, Lane, G L, Marie-Jeanne, Mélanie, Nieminen, P, and Watanabe, H

Subjects
Nuclear Physics - Experiment
Abstract

Conversion electrons from 208Bi have been measured using singles and coincidence techniques with the 208Pb(p,n)208Bi reaction at 9 MeV. The new information on multipolarities and spins complements that available from recent gamma-gamma-coincidence studies with the same reaction [Boutachkov et al., Nucl. Phys. A768, 22 (2006)]. The results on electromagnetic decays taken together with information on spectroscopic factors from earlier single-particle transfer reaction measurements represent an extensive data set on the properties of the one-proton one-neutron-hole states below 3 MeV, a spectrum which is virtually complete. Comparison of the experimental observables, namely, energies, spectroscopic factors, and gamma-branching ratios, with those calculated within the shell model allows extraction of the matrix elements of the shell model residual interaction. More than 100 diagonal and nondiagonal elements can be determined in this way, through a least squares fit to the experimental data. This adjustment of the interaction significantly affects the calculated properties of the gamma-ray transitions. Nevertheless, the matrix elements thus obtained are remarkably similar to those of a realistic interaction calculated from free-nucleon scattering. Characteristic features of the interaction are discussed.

Published
2007

8. Shape-driving effects in the triaxial nucleus, 128Xe

Author

Orce, J. N., Bruce, A. M., Emmanouilidis, A., Byrne, A. P., Dracoulis, G. D., Kibédi, T., Caamano, M., El-Masri, H., Pearson, C. J., Podolyák, Zs., Stevenson, P. D., Walker, P. M., Xu, F. R., Cullen, D. M., and Wheldon, C.

Published
2006

9. Shape-Driving Effects in the Triaxial Nucleus, Xe-128

Author

Orce, J N, Bruce, A M, Emmanouilidis, A, Byrne, A P, Dracoulis, G D, Kibedi, T, Caamano, M, El-Masri, H, Pearson, C J, Podolyak, Z, Stevenson, P D, Walker, P M, Xu, F R, Cullen, D M, and Wheldon, C

Abstract

An extended decay scheme for Xe-128 has been constructed by using data from the Sn-124(Be-9, 5n)Xe-128 reaction at a beam energy of 58 MeV. Bands have been identified as being built on several intrinsic states, including a proposed 9/2(-)[514] circle times 1/2(+)[400] two-quasineutron configuration that forms the K-pi=5(-) intrinsic state at 2228 keV, and on a previously assigned K-pi=8(-) intrinsic state at 2786 keV. A half-life of 73(3) ns has been measured for the latter. Theoretical calculations have been performed by using the configuration-constrained blocking method based on a nonaxial Woods-Saxon potential. Large gamma deformation and gamma softness are predicted for the ground state and the K-pi=5(-) intrinsic state, whereas a nearly axially symmetric shape is predicted for the K-pi=8(-) two-quasiparticle configuration. The low value of the hindrance factor for the E1 transition depopulating the K-pi=8(-) intrinsic state is discussed in the context of analogous transitions in neighbouring N=74 isotones.

Published
2006

10. High-K states in the odd-odd nuclide 180Re

Author

El-Masri, H. M., Walker, P. M., Dracoulis, G. D., Kibédi, T., Byrne, A. P., Bruce, A. M., Orce, J. N., Emmanouilidis, A., Cullen, D. M., Wheldon, C., and Xu, F. R.

Published
2005

11. Highly deformed Bands in 175Hf

Author

Scholes, D. T., Cullen, D. M., Kondev, F. G., Janssens, R. V. F., Carpenter, M. P., Hartley, D. J., Djongolov, M. K., Sletten, G., Hagemann, G., Wheldon, C., Walker, P. M., Saleem, K. Abu, Ahmad, I., Balabanski, D. L., Chowdhury, P., Danchev, M., Dracoulis, G. D., El-Masri, H. M., Goon, J., Heinz, A., Kaye, R. A., Khoo, T. L., Lauritsen, T., Lister, C. J., Moore, E. F., Riedinger, L. L., Riley, M.A., Seweryniak, M., Shestakova, I., Wiedenhöver, I., Zeidan, O., and Zhang, Jing-ye

Published
2004

14. Effective charge of the πh11/2 orbital and the electric field gradient of Hg from the yrast structure of 206Hg

Author

Fornal, B., Broda, R., Maier, K. H., Wrzesinski, J., Lane, G. J., Cromaz, M., Macchiavelli, A. O., Clark, R. M., Vetter, K., Aidan Byrne, Dracoulis, G. D., Carpenter, M. P., Janssens, R. V. F., Wiedenhoever, I., Rejmund, M., and Blomqvist, J.

Abstract

The γ-ray decay of the excited states of the two-proton hole nucleus of 206Hg was investigated using Gammasphere and 208Pb + 238U collisions. Heavy-ion multinucleon transfer processes and the (γ-γ)-time technique was used to search for yrast states in 206Hg. The result shows that the deduction of a field gradient of Hg in Hg metal is 14.3(1.0) kV/nm2.

Published
2001
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20. A Kπ=8- isomer in 136Sm

Author

Bruce, A. M., Walker, P. M., Regan, P. H., Dracoulis, G. D., Byrne, A. P., Kibedi, T., Lane, G. J., and Yeung, K. C.

Published
1994

26. Properties of Ta 187 Revealed through Isomeric Decay

Author

Walker, P. M., Hirayama, Y., Lane, G. J., Watanabe, H., Dracoulis, G. D., Ahmed, M., Brunet, M., Hashimoto, T., Ishizawa, S., Kondev, F. G., Litvinov, Yu. A., Miyatake, H., Moon, J. Y., Mukai, M., Niwase, T., Park, J. H., Podolyák, Zs., Rosenbusch, M., Schury, P., Wada, M., Watanabe, X. Y., Liang, W. Y., and Xu, F. R.

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28. Nobel symposium 152: Physics with radioactive beams

Author

Aumann, T., Blaum, K., Blumenfeld, Y., Bonaccorso, A., Borge, M. J. G., Brink, L., Sharpy, A., Dilling, J., Dracoulis, G. D., Fahlander, C., Forssén, C., Fynbo, H. O. U., Gade, A., Greenlees, P. T., Gulminelli, F., Heyde, K., Heinz, A., Hjorth-Jensen, M., Janssens, R. V. F., Jones, K. L., Björn Jonson, Kanungo, R., Khan, E., Langanke, K., Nakamura, T., Navin, A., Nazarewicz, W., Nilsson, T., Nyman, G., Nörtershäuser, W., Otsuka, T., Pfützner, M., Riisager, K., Rotureau, J., Ryberg, E., Schatz, H., Severijns, N., Simon, H., Sorlin, O., Sääf, D., Tanihata, I., Thies, R., Duppen, P., and Zhukov, M.

29. Interplay between K-isomerism and γ-softness in 128Xe

Author

Orce, J. N., Bruce, A. M., Emmanouilidis, A., Carl Wheldon, Xu, F. R., Walker, P. M., Caamaño, M., Podolyák, Zs, El-Masri, H., Stevenson, P. D., Byrne, A. P., Dracoulis, G. D., Hazel, J. C., Kibédi, T., and Cullen, D. M.

30. Identification of yrast states in 187Pb

Author

Baxter, A. M., Aidan Byrne, Dracoulis, G. D., Davidson, P. M., Mcgoram, T. R., Regan, P. H., Chandler, C., Gelletly, W., Wheldon, C., Julin, R., Cocks, J. F. C., Helariutta, K., Jones, P., Juutinen, S., Kankaanpää, H., Kettunen, H., Kuusiniemi, P., Leino, M., Muikku, M., Savelius, A., Janssens, R. V. F., Brown, T., Carpenter, M. P., Davids, C. N., Lauritsen, T., Nisius, D., and Greenlees, P. T.

Abstract

g -ray spectroscopy of the high-spin states of the neutron-deficient nucleus 187Pb has been conducted with the 155Gd(36Ar,4n) reaction. A cascade of three transitions was deduced from g -g coincidence data gated by detection of recoiling evaporation residues in a gas-filled recoil separator. In an earlier, separate experiment, two of these g rays were positively identified with 187Pb by recoil-g coincidence measurements with a high-resolution, recoil mass spectrometer. From comparison with similar sequences in heavier odd-A lead isotopes, the cascade in 187Pb is associated with the sequence of three E2 transitions from the yrast 25/2 + level to a low-lying 13/2 + isomer. The variation of excitation energy with mass number of the levels concerned suggests that their structure can be associated with weak coupling of an odd i13/2 neutron to states in the spherical well. However, the possibility that they are influenced by mixing with states in the prolate-deformed well cannot be discounted.

34. Interplay between K-isomerism and γ-softness in 128Xe

Author

Orce, J. N., Alison Bruce, Emmanouilidis, A., Wheldon, C., Xu, F. R., Walker, P. M., Caamaño, M., Podolyák, Zs, El-Masri, H., Stevenson, P. D., Byrne, A. P., Dracoulis, G. D., Hazel, J. C., Kibédi, T., and Cullen, D. M.

39. Search for hyperdeformation in U isotopes

Author

Hawcroft, D., Herzberg, R. -D, Appelbe, D. E., Peter Butler, Chewter, A. J., Jones, G. D., Rea, D. P., Aschman, D. G., Babu, B. R. S., Bark, R., Beetge, R., Benatar, M., Dracoulis, G. D., Fearick, R., Fortsch, S. V., Juutinen, S., Kankaanpää, H., Lawrie, J. J., Mabala, G. K., Mhlahlo, N., Murray, S., Naguleswaran, S., Rigollet, C., Sharpey-Schafer, J. F., Simpson, B., Smit, R., Steyn, D., Tshivhase, V. M., Whittaker, W., and Research unit Nuclear & Hadron Physics

Subjects
U-232, NUCLEI, HIGH-SPIN STATES
Abstract

The U-232 nucleus was studied in order to search for a hyperdeformed band built upon the third minimum of the fission barrier. Upper limits for the percentage population of a hypothetical hyperdeformed band relative to the ground state band are given.

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