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7 results on '"Chakrawarthy, R.S."'

1. High-spin structures in ¹³²\mathrmXe and ¹³³\mathrmXe and evidence for isomers along the ℕ=79 isotones

Author

Vogt, A., Siciliano, M., Birkenbach, B., Reiter, P., Hadyńska-Klęk, K., Wheldon, C., Valiente-Dobón, J.J., Teruya, E, Yoshinaga, N., Arnswald, K., Bazzacco, D., Blazhev, A., Bracco, A., Bruyneel, B, Chakrawarthy, R.S., Chapman, R., Cline, D., Corradi, L., Crespi, F.C.L., Cromaz, M., de Angelis, G., Eberth, J., Fallon, P., Farnea, E., Fioretto, E., Hess, H., Hetzenegger, R., Hirsch, R., Hua, H., John, P.R., Jolie, J., Jungclaus, A., Karayonchev, V., Kaya, L., Korten, W., Lee, I.Y., Leoni, S., Liang, X., Lunardi, S., Macchiavelli, A.O., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatovic, T., Montagnoli, G., Montanari, D., Müller-Gatermann, C., Napoli, D., Pearson, C.J., Podolyak, Zsolt, Pollarolo, G., Pullia, A., Queiser, M., Recchia, F., Regan, P.H., Régis, J.-M., Saed-Samii, N., Sahin, E., Scarlassara, F., Seidlitz, M., Siebeck, B., Sletten, G., Smith, J.F., Söderström, P.-A., Stefanini, A.M., Stezowski, O., Szilner, S., Szpak, B., Teng, R., Ur, C., Warner, D.D., Wolf, K., Wu, C.Y., and Zell, K.O.

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

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

Published
2017

2. High-spin structures in $^{132}$Xe and $^{133}$Xe and evidence for isomers along the $N=79$ isotones

Author

Vogt, A., Siciliano, M., Birkenbach, B., Reiter, P., Hadyńska-Klęk, K., Wheldon, C., Valiente-Dobón, J.J., Teruya, E., Yoshinaga, N., Arnswald, K., Bazzacco, D., Blazhev, A., Bracco, A., Bruyneel, B., Chakrawarthy, R.S., Chapman, R., Cline, D., Corradi, L., Crespi, F.C.L., Cromaz, M., De Angelis, G., Eberth, J., Fallon, P., Farnea, E., Fioretto, E., Fransen, C., Freeman, S.J., Fu, B., Gadea, A., Gelletly, W., Giaz, A., Görgen, A., Gottardo, A., Hayes, A.B., Hess, H., Hetzenegger, R., Hirsch, R., Hua, H., John, P.R., Jolie, J., Jungclaus, A., Karayonchev, V., Kaya, L., Korten, W., Lee, I.Y., Leoni, S., Liang, X., Lunardi, S., Macchiavelli, A.O., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatović, T., Montagnoli, G., Montanari, D., Müller-Gatermann, C., Napoli, D., Pearson, C.J., Podolyák, Zs., Pollarolo, G., Pullia, A., Queiser, M., Recchia, F., Regan, P.H., Régis, J.M., Saed-Samii, N., Şahin, E., Scarlassara, F., Seidlitz, M., Siebeck, B., Sletten, G., Smith, J.F., Söderström, P.A., Stefanini, A.M., Stezowski, O., Szilner, S., Szpak, B., Teng, R., Ur, C., Warner, D.D., Wolf, K., Wu, C.Y., Zell, K.O., Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Laue-Langevin (ILL), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), ILL, Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; The transitional nuclei Xe132 and Xe133 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in Xe136+Pb208 MNT reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (ii) in the Xe136+Pt198 MNT reaction employing the GAMMASPHERE spectrometer in combination with the gas-detector array CHICO, and (iii) as an evaporation residue after a Te130(α,xn)Xe134−xn fusion-evaporation reaction employing the HORUS γ-ray array at the University of Cologne. The high-spin level schemes are considerably extended above the Jπ=(7−) and (10+) isomers in Xe132 and above the 11/2− isomer in Xe133. The results are compared to the high-spin systematics of the Z=54 as well as the N=78 and N=79 chains. Furthermore, evidence is found for a long-lived (T1/2≫1μs) isomer in Xe133 which closes a gap along the N=79 isotones. Shell-model calculations employing the SN100PN and PQM130 effective interactions reproduce the experimental findings and provide guidance to the interpretation of the observed high-spin features.

Published
2017

3. Isomers and high-spin structures in the N = 81 isotones 135Xe and 137Ba

Author

Vogt, A., Birkenbach, B., Reiter, P., Blazhev, A., Siciliano, M., Hadynska_Klek, K., Valiente-Dobón, J.J., Wheldon, C., Teruya, E., Yoshinaga, N., Arnswald, K., Bazzacco, D., Bowry, M., Bracco, A., Bruyneel, B., Chakrawarthy, R.S., Chapman, R., Cline, D., Corradi, L., Crespi, F.C.L., Cromaz, M., de Angelis, G., Eberth, J., Fallon, P., Farnea, E., Fioretto, E., Freeman, S.J., Fu, B., Gadea, A., Geibel, K., Gelletly, W., Gengelbach, A., Giaz, A., Görgen, A., Gottardo, A., Hayes, A.B., Hess, H., Hirsch, R., Hua, H., John, P.R., Jolie, J., Jungclaus, A., Kaya, L., Korten, W., Lee, I.Y., Leoni, S., Lewandowski, L., Liang, X., Lunardi, S., Macchiavelli, A.O., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatović, Tea, Montagnoli, G., Montanari, D., Muller-Gatermann C., Napoli, D., Pearson, C.J., Pellegri, L., Podolyak, Zs., Pollarolo, G., Pullia, A., Queiser, M., Radeck, F., Recchia, F., Regan, P.H., Rosiiak, D., Saed-Samii, N., Sahin, E., Scarlassara, F., Schneiders, D., Seidlitz, M., Siebeck, B., Sletten, G., Smith, J. F., Söderström, P.-A., Stefanini, A.M., Steinbach, T., Stezowski, O., Szilner, Suzana, Szpak, B., Teng, R., Ur, C., Vandone, V., Warner, D.D., Wiens, A., Wu, C.Y., and Zell, K. O.

Subjects
multinucleon-transfer reaction, high-spin structures
Abstract

The high-spin structures and isomers of the N = 81 isotones 135Xe and 137Ba are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in 136Xe+238U and (ii) 136Xe+208Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii) in the 136Xe+198Pt MNT reaction employing the γ -ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a 11B+130Te fusion-evaporation reaction with the HORUS γ -ray array at the University of Cologne. The high-spin level schemes of 135Xe and 137Ba are considerably extended to higher energies. The 2058-keV (19/2−) state in 135Xe is identified as an isomer, closing a gap in the systematics along the N = 81 isotones. Its half-life is measured to be 9.0(9) ns, corresponding to a reduced transition probability of B(E2, 19/2− → 15/2−) = 0.52(6) W.u. The experimentally deduced reduced transition probabilities of the isomeric states are compared to shell-model predictions. Latest shell-model calculations reproduce the experimental findings generally well and provide guidance to the interpretation of the new levels.

Published
2017

4. Isomers and high-spin structures in the $N$=81 isotones $^{135}$Xe and $^{137}$Ba

Author

Vogt, A., Birkenbach, B., Reiter, P., Blazhev, A., Siciliano, M., Hadyńska-Klęk, K., Valiente-Dobón, J.J., Wheldon, C., Teruya, E., Yoshinaga, N., Arnswald, K., Bazzacco, D., Bowry, M., Bracco, A., Bruyneel, B., Chakrawarthy, R.S., Chapman, R., Cline, D., Corradi, L., Crespi, F.C. L, Cromaz, M., De Angelis, G., Eberth, J., Fallon, P., Farnea, E., Fioretto, E., Freeman, S.J., Fu, B., Gadea, A., Geibel, K., Gelletly, W., Gengelbach, A., Giaz, A., Görgen, A., Gottardo, A., Hayes, A.B., Hess, H., Hirsch, R., Hua, H., John, P.R., Jolie, J., Jungclaus, A., Kaya, L., Korten, W., Lee, I.Y., Leoni, S., Lewandowski, L., Liang, X., Lunardi, S., Macchiavelli, A.O., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatović, T., Montagnoli, G., Montanari, D., Müller-Gatermann, C., Napoli, D., Pearson, C.J., Pellegri, L., Podolyák, Zs., Pollarolo, G., Pullia, A., Queiser, M., Radeck, F., Recchia, F., Regan, P.H., Rosiak, D., Saed-Samii, N., Şahin, E., Scarlassara, F., Schneiders, D., Seidlitz, M., Siebeck, B., Sletten, G., Smith, J.F., Söderström, P.A., Stefanini, A.M., Steinbach, T., Stezowski, O., Szilner, S., Szpak, B., Teng, R., Ur, C., Vandone, V., Warner, D.D., Wiens, A., Wu, C.Y., Zell, K.O., Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de Physique des Particules (ex SPP) (DPP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique des Particules (ex SPP) (DPhP), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

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

Published
2017

5. High-spin structure of 134Xe

Author

Vogt, A., Birkenbach, B., Reiter, P., Blazhev, A., Siciliano, M., Valiente-Dobón, J.J., Wheldon, C., Bazzacco, D., Bowry, M., Bracco, A., Bruyneel, B., Chakrawarthy, R.S., Chapman, R., Cline, D., Corradi, L., Crespi, F.C.L., Cromaz, M., de Angelis, G., Eberth, J., Fallon, P., Farnea, E., Fioretto, E., Freeman, S.J., Gadea, A., Geibel, K., Gelletly, W., Gengelbach, A., Giaz, A., Görgen, A., Gottardo, A., Hayes, A.B., Hess, H., Hua, H., John, P.R., Jolie, J., Jungclaus, A., Korten, W., Lee, I.Y., Leoni, S., Liang, X., Lunardi, S., Macchiavelli, A.O., Menegazzo, R., Mengoni, D., Michelagnoli, C., Mijatovic, Tea, Montagnoli, G., Montanari, D., Napoli, D., Pearson, C.J., Pellegri, L., Podolyak, Zs., Pollarolo, G., Pullia, A., Radeck, F., Recchia, F., Regan, P.H., Sahin, E., Scarlassara, F., Sletten, G., Smith, J.F., Söderström, P.-A., Stefanini, A.M., Steinbach, T., Stezowski, O., Szilner, Suzana, Szpak, B., Teng, R., Ur, C., Vandone, V., Ward, D., Warner, D.D., Wiens, A., and Wu, C.Y.

Subjects
gamma-spectroscopy, the neutron-rich Xe, AGATA and CLARA spectrometers, Nuclear Experiment
Abstract

Detailed spectroscopic information in the N~82 region is necessary to benchmark shell-model calculations in the region. The nuclear structure above long-lived isomers in 134Xe is investigated after multinucleon transfer (MNT) and actinide fission. 134Xe was populated as (i) a transfer product in 136Xe+238U, and 136Xe+208Pb MNT reactions and (ii) as a fission product in the 136Xe+238U reaction employing the high-resolution Advanced Gamma Tracking Array (AGATA). Trajectory reconstruction has been applied for the complete identification of beamlike transfer products with the magnetic spectrometer PRISMA. The 136Xe+198Pt MNT reaction was studied with the gamma-ray spectrometer GAMMASPHERE in combination with the gas detector array Chico. Several highspin states in 134Xe on top of the two long-lived isomers are discovered based on gamma-gamma coincidence relationships and information on the gamma-ray angular distributions as well as excitation energies from the total kinetic energy loss and fission fragments. The revised level scheme of 134Xe is extended up to an excitation energy of 5.832 MeV with tentative spin-parity assignments up to 16+. Previous assignments of states above the 7- isomer are revised. Latest shell model calculations employing two different effective interactions reproduce the experimental findings quite well and support the new spin and parity assignments.

Published
2016

6. High-spin, multiparticle isomers in Sb121,123

Author

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

Abstract

Isomers in near-spherical Z=51, antimony isotopes are reported here for the first time using fusion-fission reactions between Al27 and a pulsed Hf178 beam of energy, 1150 MeV. γ rays were observed from the decay of isomeric states with half-lives, T1/2=200(30) and 52(3)μs, and angular momenta I=(252) and Iπ=232+, in Sb121,123, respectively. These states are proposed to correspond to ν(h112)2 configurations, coupled to an odd d52 or g72 proton. Nanosecond isomers were also identified at Iπ=192- [T1/2=8.5(5) ns] in Sb121 and Iπ=(152-) [T1/2=37(4) ns] in Sb123. 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
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7. Identification of a High-Spin Isomer in Mo-99

Author

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

Abstract

A previously unreported isomer has been identified in Mo-99 at an excitation energy of E-x = 3010 keV, decaying with a half-life of T-1/2 = 8(2) ns. The nucleus of interest was produced following fusion-fission reactions between a thick Al-27 target frame and a Hf-178 beam at a laboratory energy of 1150 MeV. This isomeric state is interpreted as an energetically favored, maximally aligned configuration of nu h (11/2) circle times pi(g (9/2))(2).

Published
2007

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