Search

Your search keyword '"Forsberg, U."' showing total 19 results
Start Over Author "Forsberg, U." Publisher american physical society
19 results on '"Forsberg, U."'

1. Search for elements 119 and 120

Author

Khuyagbaatar, J., Yakushev, A., Düllmann, Ch. E., Ackermann, D., Andersson, L.-L., Asai, M., Block, M., Boll, R.A., Brand, H., Cox, D. M., Dasgupta, M., Derkx, X., Di Nitto, A., Eberhardt, K., Even, J., Evers, M., Fahlander, C., Forsberg, U., Gates, J. M., Gharibyan, N., Golubev, P., Gregorich, K. E., Hamilton, J. H., Hartmann, W., Herzberg, R.-D., Heßberger, F. P., Hinde, D. J., Hoffmann, J., Hollinger, R., Hübner, A., Jäger, E., Kindler, B., Kratz, J.V., Krier, J., Kurz, N., Laatiaoui, M., Lahiri, S., Lang, R., Lommel, B., Maiti, M., Miernik, K., Minami, S., Mistry, A. K., Mokry, C., Nitsche, H., Omtvedt, J. P., Pang, G. K., Papadakis, P., Renisch, D., Roberto, J. B., Rudolph, D., Runke, J., Rykaczewski, K. P., Sarmiento Pico, Luis, Schädel, M., Schausten, B., Semchenkov, A., Shaughnessy, D. A., Steinegger, P., Steiner, J., Tereshatov, E. E., Thörle-Pospiech, P., Tinschert, K., Torres De Heidenreich, T., Trautmann, N., Türler, A., Uusitalo, J., Wegrzecki, M., Wiehl, N., Van Cleve, S. M., Yakusheva, V., Khuyagbaatar, J., Yakushev, A., Düllmann, Ch. E., Ackermann, D., Andersson, L.-L., Asai, M., Block, M., Boll, R.A., Brand, H., Cox, D. M., Dasgupta, M., Derkx, X., Di Nitto, A., Eberhardt, K., Even, J., Evers, M., Fahlander, C., Forsberg, U., Gates, J. M., Gharibyan, N., Golubev, P., Gregorich, K. E., Hamilton, J. H., Hartmann, W., Herzberg, R.-D., Heßberger, F. P., Hinde, D. J., Hoffmann, J., Hollinger, R., Hübner, A., Jäger, E., Kindler, B., Kratz, J.V., Krier, J., Kurz, N., Laatiaoui, M., Lahiri, S., Lang, R., Lommel, B., Maiti, M., Miernik, K., Minami, S., Mistry, A. K., Mokry, C., Nitsche, H., Omtvedt, J. P., Pang, G. K., Papadakis, P., Renisch, D., Roberto, J. B., Rudolph, D., Runke, J., Rykaczewski, K. P., Sarmiento Pico, Luis, Schädel, M., Schausten, B., Semchenkov, A., Shaughnessy, D. A., Steinegger, P., Steiner, J., Tereshatov, E. E., Thörle-Pospiech, P., Tinschert, K., Torres De Heidenreich, T., Trautmann, N., Türler, A., Uusitalo, J., Wegrzecki, M., Wiehl, N., Van Cleve, S. M., and Yakusheva, V.

Abstract

A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the 50Ti+249Bk and 50Ti+249Cf fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the 249Bk target partially decayed into 249Cf, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the 50Ti+249Bk and 50Ti+249Cf reactions, respectively, at a midtarget beam energy of Elab = 281.5 MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical predictions on the fission-barrier heights of superheavy nuclei in the region of the island of stability.

Published
2020

2. β Decay of 127Cd and Excited States in 127In

Author

Lorenz, Ch., Sarmiento, L. G., Rudolph, D., Golubev, P., Eronen, Tommi, Nesterenko, Dmitrii, Kankainen, Anu, Canete, Laetitia, Cox, Daniel, Fernandez, A., Forsberg, U., Jungclaus, A., Kojouharov, I., Kurz, N., Lalovic, N., Partanen, Jari, Reponen, Mikael, Rinta-Antila, Sami, de Roubin, Antoine, Såmark-Roth, A., Vaquero, V., and Vilén, Markus

Subjects
electromagnetic transitions, gamma-ray spectroscopy, nuclear shell model, Penning trap, Subatomic Physics, shell model, isomer decay, beta decay, ydinfysiikka, nuclear structure and decays, Gamow-Teller strength
Abstract

A dedicated spectroscopic study of the β decay of 127Cd was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, β−γ−γcoincidences were used to considerably extend the decay scheme of 127In. The β-decaying 3/2+ and 11/2− states in 127Cd have been identified with the 127Cd ground state and the 283-keV isomer. Their respective half-lives have been measured to 0.45(128)s and 0.36(4) s. The experimentally observed βfeeding to excited states of 127In and the decay scheme of 127In are discussed in conjunction with large-scale shell-model calculations. peerReviewed

Published
2019

3. β Decay of 127Cd and Excited States in 127In

Author

Lorenz, Ch, Sarmiento, L. G., Rudolph, D., Golubev, P., Eronen, T., Nesterenko, D. A., Kankainen, A., Canete, L., Cox, D. M., Fernandez, A., Forsberg, U., Jungclaus, A., Kojouharov, I., Kurz, N., Lalović, N., Partanen, J., Reponen, M., Rinta-Antila, S., De Roubin, A., Såmark-Roth, A., Vaquero, V., Vilén, M., Lorenz, Ch, Sarmiento, L. G., Rudolph, D., Golubev, P., Eronen, T., Nesterenko, D. A., Kankainen, A., Canete, L., Cox, D. M., Fernandez, A., Forsberg, U., Jungclaus, A., Kojouharov, I., Kurz, N., Lalović, N., Partanen, J., Reponen, M., Rinta-Antila, S., De Roubin, A., Såmark-Roth, A., Vaquero, V., and Vilén, M.

Abstract

A dedicated spectroscopic study of the β decay of 127Cd was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, β-γ-γ coincidences were used to considerably extend the decay scheme of 127In. The β-decaying 3/2+ and 11/2- states in 127Cd have been identified with the 127Cd ground state and the 283-keV isomer. Their respective half-lives have been measured to 0.45(+12-8)s and 0.36(4) s. The experimentally observed β feeding to excited states of 127In and the decay scheme of 127In are discussed in conjunction with large-scale shell-model calculations.

Published
2019

4. Fusion reaction 48Ca + 249Bk leading to formation of the element Ts (Z=117)

Author

Khuyagbaatar, J., Yakushev, A., Düllmann, Ch E., Ackermann, D., Andersson, L. L., Asai, M., Block, M., Boll, R. A., Brand, H., Cox, D. M., Dasgupta, M., Derkx, X., Di Nitto, A., Eberhardt, K., Even, J., Evers, M., Fahlander, C., Forsberg, U., Gates, J. M., Gharibyan, N., Golubev, P., Gregorich, K. E., Hamilton, J. H., Hartmann, W., Herzberg, R. D., Heßberger, F. P., Hinde, D. J., Hoffmann, J., Hollinger, R., Hübner, A., Jäger, E., Kindler, B., Kratz, J. V., Krier, J., Kurz, N., Laatiaoui, M., Lahiri, S., Lang, R., Lommel, B., Maiti, M., Miernik, K., Minami, S., Mistry, A., Mokry, C., Nitsche, H., Omtvedt, J. P., Pang, G. K., Papadakis, P., Renisch, D., Roberto, J., Rudolph, D., Runke, J., Rykaczewski, K. P., Sarmiento, L. G., Schädel, M., Schausten, B., Semchenkov, A., Shaughnessy, D. A., Steinegger, P., Steiner, J., Tereshatov, E. E., Thörle-Pospiech, P., Tinschert, K., Torres De Heidenreich, T., Trautmann, N., Türler, A., Uusitalo, J., Ward, D. E., Wegrzecki, M., Wiehl, N., Van Cleve, S. M., Yakusheva, V., Khuyagbaatar, J., Yakushev, A., Düllmann, Ch E., Ackermann, D., Andersson, L. L., Asai, M., Block, M., Boll, R. A., Brand, H., Cox, D. M., Dasgupta, M., Derkx, X., Di Nitto, A., Eberhardt, K., Even, J., Evers, M., Fahlander, C., Forsberg, U., Gates, J. M., Gharibyan, N., Golubev, P., Gregorich, K. E., Hamilton, J. H., Hartmann, W., Herzberg, R. D., Heßberger, F. P., Hinde, D. J., Hoffmann, J., Hollinger, R., Hübner, A., Jäger, E., Kindler, B., Kratz, J. V., Krier, J., Kurz, N., Laatiaoui, M., Lahiri, S., Lang, R., Lommel, B., Maiti, M., Miernik, K., Minami, S., Mistry, A., Mokry, C., Nitsche, H., Omtvedt, J. P., Pang, G. K., Papadakis, P., Renisch, D., Roberto, J., Rudolph, D., Runke, J., Rykaczewski, K. P., Sarmiento, L. G., Schädel, M., Schausten, B., Semchenkov, A., Shaughnessy, D. A., Steinegger, P., Steiner, J., Tereshatov, E. E., Thörle-Pospiech, P., Tinschert, K., Torres De Heidenreich, T., Trautmann, N., Türler, A., Uusitalo, J., Ward, D. E., Wegrzecki, M., Wiehl, N., Van Cleve, S. M., and Yakusheva, V.

Abstract

The heaviest currently known nuclei, which have up to 118 protons, have been produced in 48Ca induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing 48Ca with the radioactive target 249Bk, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short α decay chains were observed. The long chains were attributed to the decay of 294Ts. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to 293Ts. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts.

Published
2019

5. Low-lying states in 219Ra and 215Rn : Sampling microsecond α-decaying nuclei

Author

Såmark-Roth, A., Sarmiento, L. G., Rudolph, D., Ljungberg, J., Carlsson, B. G., Fahlander, C., Forsberg, U., Golubev, P., Ragnarsson, I., Ackermann, D., Andersson, L. L., Block, M., Brand, H., Cox, D. M., Di Nitto, A., Düllmann, Ch E., Eberhardt, K., Even, J., Gates, J. M., Gerl, J., Gregorich, K. E., Gross, C. J., Herzberg, R. D., Heßberger, F. P., Jäger, E., Khuyagbaatar, J., Kindler, B., Kojouharov, I., Kratz, J. V., Krier, J., Kurz, N., Lommel, B., Mistry, A., Mokry, C., Omtvedt, J. P., Papadakis, P., Runke, J., Rykaczewski, K., Schädel, M., Schaffner, H., Schausten, B., Thörle-Pospiech, P., Trautmann, N., Torres, T., Türler, A., Ward, A., Wiehl, N., and Yakushev, A.

Subjects
alpha decay, gamma-ray spectroscopy, nuclear shell model, pulse shape analysis, Subatomic Physics, half life, Nilsson-Strutinsky calculations
Abstract

Short-lived α-decaying nuclei "northeast" of 208Pb in the chart of nuclides were studied using the reaction 48Ca+243Am with the decay station TASISpec at TASCA, GSI Darmstadt. Decay energies and times from pile-up events were extracted with a tailor-made pulse-shape analysis routine and specific α-decay chains were identified in a correlation analysis. Decay chains starting with the even-even 220Ra and its odd-A neighbors, 219Fr, and 219,221Ra, with a focus on the 219Ra→215Rn decay, were studied by means of α-γ spectroscopy. A revised α-decay scheme of 219Ra is proposed, including a new decay branch from a previously not considered isomeric state at 17 keV excitation energy. Conclusions on nuclear structure are drawn from the experimental data, aided by Geant4 simulations and a discussion on theoretical calculations.

Published
2018

6. Quantum-state-selective decay spectroscopy of 213Ra

Author

Lorenz, Ch, Sarmiento, L. G., Rudolph, D., Ward, D. E., Block, M, Heßberger, F. P., Ackermann, D., Andersson, L. L., Cortés, Manuel Lazo, Droese, C., Dworschak, M., Eibach, M., Forsberg, U., Golubev, P., Hoischen, R., Kojouharov, I, Khuyagbaatar, J., Nesterenko, D., Ragnarsson, I., Schaffner, H, Schweikhard, L., Stolze, S., and Wenzl, J.

Subjects
gamma-ray spectroscopy, nuclear shell model, alpha decay, Physics::Instrumentation and Detectors, Penning trap, Subatomic Physics, nuclear structure, shell model, nuclear decays, Nilsson-Strutinsky calculations, Nuclear Experiment
Abstract

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the spectroscopic results call for a revision of the decay path of 213Ra, thereby exemplifying the potential of a combination of a mass-selective Penning trap device with a dedicated nuclear decay station and contemporary geant4 simulations. peerReviewed

Published
2017

7. ⁴⁸Ca+²⁴⁹Bk Fusion Reaction Leading to Element Z=117: Long-Lived alpha-Decaying ²⁷⁰Db and Discovery of ²⁶⁶Lr

Author

Khuyagbaatar, J, Yakushev, A, Duellmann, Ch E, Ackermann, D, Andersson, L-L, Asai, M, Block, M, Boll, RA, Brand, H, Cox, DM, Dasgupta, M, Derkx, X, Di Nitto, A, Eberhardt, K, Even, J, Evers, M, Fahlander, C, Forsberg, U, Gates, JM, Gharibyan, N, Golubev, P, Gregorich, KE, Hamilton, JH, Hartmann, W, Herzberg, R-D, Hessberger, FP, Hinde, DJ, Hoffmann, J, Hollinger, R, Huebner, A, Jaeger, E, Kindler, B, Kratz, JV, Krier, J, Kurz, N, Laatiaoui, M, Lahiri, S, Lang, R, Lommel, B, Maiti, M, Miernik, K, Minami, S, Mistry, A, Mokry, C, Nitsche, H, Omtvedt, JP, Pang, GK, Papadakis, P, Renisch, D, Roberto, J, Rudolph, D, Runke, J, Rykaczewski, KP, Sarmiento, LG, Schaedel, M, Schausten, B, Semchenkov, A, Shaughnessy, DA, Steinegger, P, Steiner, J, Tereshatov, EE, Thoerle-Pospiech, P, Tinschert, K, De Heidenreich, T Torres, Trautmann, N, Tuerler, A, Uusitalo, J, Ward, DE, Wegrzecki, M, Wiehl, N, Van Cleve, SM, and Yakusheva, V

Published
2014

8. 48Ca+249Bk Fusion Reaction Leading to Element Z = 117: Long-Lived alpha-Decaying 270Db and Discovery of 266Lr

Author

Hübner, A., Yakusheva, V., Forsberg, U., Rudolph, D., Kurz, N., Ackermann, D., Tereshatov, E. E., Omtvedt, J. P., Herzberg, R.-D., Steinegger, P., Hartmann, W., Golubev, P., Tinschert, K., Runke, J., Wegrzecki, M., Eberhardt, K., Schausten, B., Block, M., Laatiaoui, M., Even, J., Asai, M., Semchenkov, A., Maiti, M., Gharibyan, N., Mistry, A., Miernik, K., Pang, G. K., Gregorich, K. E., Nitsche, H., Hoffmann, J., Düllmann, Ch. E., Steiner, J., Di Nitto, A., Khuyagbaatar, J., Trautmann, N., Krier, J., Brand, H., Derkx, X., Yakushev, A., Thörle-Pospiech, P., Jäger, E., Hamilton, J. H., Roberto, J., Van Cleve, S. M., Schädel, M., Shaughnessy, D. A., Torres De Heidenreich, T., Lahiri, S., Heßberger, F. P., Papadakis, P., Minami, S., Mokry, C., Renisch, D., Kindler, B., Hinde, D. J., Fahlander, C., Evers, M., Türler, Andreas, Uusitalo, J., Ward, D. E., Kratz, J. V., Andersson, L.-L., Cox, D. M., Wiehl, N., Boll, R. A., Hollinger, R., Lang, R., Gates, J. M., Dasgupta, M., Rykaczewski, K. P., Sarmiento, L. G., and Lommel, B.

Subjects
540 Chemistry, 570 Life sciences, biology
Published
2014
Full Text
View/download PDF

9. Ca-48+Bk-249 Fusion Reaction Leading to Element Z=117: Long-Lived alpha-Decaying (270)Db and Discovery of Lr-266

Author

Khuyagbaatar, J, Yakushev, A, Duellmann, Ch E, Ackermann, D, Andersson, L-L, Asai, M, Block, M, Boll, RA, Brand, H, Cox, DM, Dasgupta, M, Derkx, X, Di Nitto, A, Eberhardt, K, Even, J, Evers, M, Fahlander, C, Forsberg, U, Gates, JM, Gharibyan, N, Golubev, P, Gregorich, KE, Hamilton, JH, Hartmann, W, Herzberg, R-D, Hessberger, FP, Hinde, DJ, Hoffmann, J, Hollinger, R, Huebner, A, Jaeger, E, Kindler, B, Kratz, JV, Krier, J, Kurz, N, Laatiaoui, Mustapha, Lahiri, S, Lang, R, Lommel, B, Maiti, M, Miernik, K, Minami, S, Mistry, A, Mokry, C, Nitsche, H, Omtvedt, JP, Pang, GK, Papadakis, P, Renisch, D, Roberto, J, Rudolph, D, Runke, J, Rykaczewski, KP, Sarmiento, LG, Schaedel, M, Schausten, B, Semchenkov, A, Shaughnessy, DA, Steinegger, P, Steiner, J, Tereshatov, EE, Thoerle-Pospiech, P, Tinschert, K, Torres De Heidenreich, T, Trautmann, N, Tuerler, A, Uusitalo, J, Ward, DE, Wegrzecki, M, Wiehl, N, Van Cleve, SM, and Yakusheva, V

Subjects
superheavy nuclei, separator, gsi, tasca, ca-48-inducted reactions, heaviest elements
Abstract

The superheavy element with atomic number Z=117 was produced as an evaporation residue in the 48Ca+249Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope 294117 and its decay products. A hitherto unknown α-decay branch in 270Db (Z=105) was observed, which populated the new isotope 266Lr (Z=103). The identification of the long-lived (T1/2=1.0+1.9−0.4 h) α-emitter 270Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an “island of stability.” ispartof: Physical Review Letters vol:112 issue:17 ispartof: location:United States status: published

Published
2014

10. Spectroscopy of Element 115 Decay Chains.

Author

Rudolph, D., Forsberg, U., Golubev, P., Sarmiento, L. G., Yakushev, A., Andersson, L.-L., Di Nitto, A., Düllmann, Ch. E., Gates, J. M., Gregorich, K. E., Gross, C. J., Heßberger, F. P., Herzberg, R.-D., Khuyagbaatar, J., Kratz, J. V., Rykaczewski, K., Schädel, M., Aberg, S., Ackermann, D., and Block, M.

Subjects
*X-rays, *SPECTRUM analysis, *MONTE Carlo method, *CHEMICAL reactions, *EVAPORATION (Chemistry)
Abstract

A high-resolution a, x-ray, and y-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z> 112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

11. New Short-Lived Isotope 221U and the Mass Surface Near N = 126.

Author

Khuyagbaatar, J., Yakushev, A., Dullmann, Ch. E., Ackermann, D., Andersson, L.-L., Block, M., Brand, H., Cox, D. M., Even, J., Forsberg, U., Golubev, P., Hartmann, W., Herzberg, R.-D., Heßberger, F. P., Hoffmann, J., Hübner, A., Jäger, E., Jeppsson, J., Kindler, B., and Kratz, J. V.

Subjects
*URANIUM isotopes, *NUCLEAR fusion, *HEAVY nuclei, *NUCLEAR structure, *QUANTUM mechanics
Abstract

Two short-lived isotopes 221U and 222U were produced as evaporation residues in the fusion reaction 50Ti + 176Yb at the gas-filled recoil separator TASCA. An a decay with an energy of Eα = 9.31(5) MeV and half-life T1/2 = 4.7(7) μs was attributed to 222U. The new isotope 221U was identified in α-decay chains starting with Eα = 9.71(5) MeV and T1/2 = 0.66(14) μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N = 126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of a-decay reduced width. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

12. Decay spectroscopy of element 115 daughters: 280Rg →276Mt and 276Mt → 272Bth.

Author

Gates, J. M., Gregorich, K. E., Gothe, O. R., Uribe, E. C., Pang, G. K., Bleuel, D. L., Block, M., Clark, R. M., Campbell, C. M., Crawford, H. L., Cromaz, M., Di Nitto, A., Düllmann, Ch. E., Esker, N. E., Fahlander, C., Fallon, P., Farjadi, R. M., Forsberg, U., Khuyagbaatar, J., and Loveland, W.

Subjects
*DECAY chains, *SUPERHEAVY elements, *SPONTANEOUS fission, *X-ray spectroscopy, *COMPTON scattering, FLEROV Laboratory of Nuclear Reactions (Dubna, Russia)
Abstract

Forty-six decay chains, assigned to the decay of 288115, were produced using the 243Am)(48,3n)288115 reaction at the Lawrence Berkeley National Laboratory 88-in. cyclotron. The resulting series of α decays were studied using α-photon and α-x-ray spectroscopies. Multiple α-photon coincidences were observed in the element 115 decay chain members, particularly in the third- and fourth-generation decays (presumed to be 280Rg and 276Mt, respectively). Upon combining these data with those from 22 288115 decay chains observed in a similar experiment, updated level schemes in 276Mt and 272Bh (populated by the α decay of 280Rg and 276Mt, respectively) are proposed. Photons were observed in the energy range expected for K x rays coincident with the α decay of both 280Rg and 276Mt. However, Compton scattering of higher-energy γ rays and discrete transitions are present in the K x-ray region preventing a definitive Z identification to be made based on observation of characteristic K x-ray energies. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

13. Decay of the high-Jt isomeric state to a rotational band in 257Rf.

Author

Rissanen, J., Clark, R. M., Gregorich, K. E., Gates, J. M., Campbell, C. M., Crawford, H. L., Cromaz, M., Esker, N. E., Fallon, P., Forsberg, U., Gothe, O., Lee, I.-Y., Liu, H. L., Machiavelli, A. O., Mudder, P., Nitsche, H., Pang, G., Rice, A., Rudolph, D., and Stoyer, M. A.

Subjects
*NUCLEAR isomers, *NUCLEAR rotational states, *RUTHERFORDIUM, *NUCLEAR fusion, *NUCLEAR reactions, *ELECTRONS, LEAD isotope decay
Abstract

The 257Rf isotope has beéri populated via the 208Pb(50)Ti, n) fusion-evaporation reaction and delayed y-ray and electron decay spectroscopy has been performed. The existence of a high- K isomeric state in 257Rf has been confirmed. The isomeric state decays into a rotational band based on the 11/2-[725] excitation, which was observed up to spin of (23/2-). Three multipolarity-El y transitions depopulating the isomeric state have been observed, which fixes the spin for that state to (21/2+). This assignment agrees with theoretical predictions calculated with the microscopic-macroscopic approach, which suggest the isomeric state to be formed by coupling an unpaired 11/2- [725] quasineuiron to the (1/2-[521] ⊗ 9/2+[624])5- two-quasiproton state. The same two-quasiproton excitation is possible for the lowest isomer in 256Rf. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

14. First superheavy element experiments at the GSI recoil separator TASCA: The production and decay of element 114 in the 244Pu(48Ca,3-4n) reaction.

Author

Gates, J. M., Düllmann, Ch. E., Schädel, M., Yakushev, A., Türler, A., Eberhardt, K., Kratz, J. V., Ackermann, D., Andersson, L.-L., Block, M., Brüchle, W., Dvorak, J., Essel, H. G., Ellison, P. A., Even, J., Forsberg, U., Gellanki, J., Gorshkov, A., Graeger, R., and Gregorich, K. E.

Subjects
*SUPERHEAVY elements, *ISOTOPES, *ION bombardment, *COLLISIONAL excitation, *NUCLEAR cross sections, *ELECTRON-nucleus scattering
Abstract

Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of 48Ca to irradiate targets of 206-208Pb, which led to the production of 252-254No isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 (288-291114) were produced in irradiations of 244Pu targets with 48Ca beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new α-decay branch in 281Ds was observed, leading to the new nucleus 277Hs. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

15. β decay of 127Cd and excited states in 127In.

Author

Lorenz, Ch., Sarmiento, L. G., Rudolph, D., Golubev, P., Eronen, T., Nesterenko, D. A., Kankainen, A., Canete, L., Cox, D. M., Fernandez, A., Forsberg, U., Jungclaus, A., Kojouharov, I., Kurz, N., Lalović1, N., Partanen, J., Reponen, M., Rinta-Antila, S., de Roubin, A., and Såmark-Roth, A.

Subjects
*EXCITED states, *COLLEGE facilities, *COINCIDENCE, *ISOMERS
Abstract

A dedicated spectroscopic study of the ß decay of 127Cd was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, β-γ-γ coincidences were used to considerably extend the decay scheme of 127In. The β-decaying 3/2+ and 11/2- states in 127Cd have been identified with the 127Cd ground state and the 283-keV isomer. Their respective half-lives have been measured to 0.45(128)s and 0.36(4) s. The experimentally observed β feeding to excited states of 127In and the decay scheme of 127In are discussed in conjunction with large-scale shell-model calculations. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

16. Quantum-state-selective decay spectroscopy of 213Ra.

Author

Lorenz, Ch., Sarmiento, L. G., Rudolph, D., Ward, D. E., Block, M., Heßberger, F. P., Ackermann, D., Andersson, L.-L., Cortés, M. L., Droese, C., Dworschak, M., Eibach, M., Forsberg, U., Golubev, P., Hoischen, R., Kojouharov, I., Khuyagbaatar, J., Nesterenko, D., Ragnarsson, I., and Schaffner, H.

Subjects
*QUANTUM states, *RADIUM, *SPECTROMETRY
Abstract

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the 5n evaporation channel 213Ra was mass-selected in SHIPTRAP, and the 213Ra ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 simulations and supported by theoretical calculations, the spectroscopic results call for a revision of the decay path of 213Ra, thereby exemplifying the potential of a combination of a mass-selective Penning trap device with a dedicated nuclear decay station and contemporary geant4 simulations. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

17. Spectroscopy along Flerovium Decay Chains: Discovery of ^{280}Ds and an Excited State in ^{282}Cn.

Author

Såmark-Roth A, Cox DM, Rudolph D, Sarmiento LG, Carlsson BG, Egido JL, Golubev P, Heery J, Yakushev A, Åberg S, Albers HM, Albertsson M, Block M, Brand H, Calverley T, Cantemir R, Clark RM, Düllmann CE, Eberth J, Fahlander C, Forsberg U, Gates JM, Giacoppo F, Götz M, Götz S, Herzberg RD, Hrabar Y, Jäger E, Judson D, Khuyagbaatar J, Kindler B, Kojouharov I, Kratz JV, Krier J, Kurz N, Lens L, Ljungberg J, Lommel B, Louko J, Meyer CC, Mistry A, Mokry C, Papadakis P, Parr E, Pore JL, Ragnarsson I, Runke J, Schädel M, Schaffner H, Schausten B, Shaughnessy DA, Thörle-Pospiech P, Trautmann N, and Uusitalo J

Abstract

A nuclear spectroscopy experiment was conducted to study α-decay chains stemming from isotopes of flerovium (element Z=114). An upgraded TASISpec decay station was placed behind the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. The fusion-evaporation reactions ^{48}Ca+^{242}Pu and ^{48}Ca+^{244}Pu provided a total of 32 flerovium-candidate decay chains, of which two and eleven were firmly assigned to ^{286}Fl and ^{288}Fl, respectively. A prompt coincidence between a 9.60(1)-MeV α particle event and a 0.36(1)-MeV conversion electron marked the first observation of an excited state in an even-even isotope of the heaviest man-made elements, namely ^{282}Cn. Spectroscopy of ^{288}Fl decay chains fixed Q_{α}=10.06(1)  MeV. In one case, a Q_{α}=9.46(1)-MeV decay from ^{284}Cn into ^{280}Ds was observed, with ^{280}Ds fissioning after only 518  μs. The impact of these findings, aggregated with existing data on decay chains of ^{286,288}Fl, on the size of an anticipated shell gap at proton number Z=114 is discussed in light of predictions from two beyond-mean-field calculations, which take into account triaxial deformation.

Published
2021
Full Text
View/download PDF

18. New Short-Lived Isotope ^{221}U and the Mass Surface Near N=126.

Author

Khuyagbaatar J, Yakushev A, Düllmann ChE, Ackermann D, Andersson LL, Block M, Brand H, Cox DM, Even J, Forsberg U, Golubev P, Hartmann W, Herzberg RD, Heßberger FP, Hoffmann J, Hübner A, Jäger E, Jeppsson J, Kindler B, Kratz JV, Krier J, Kurz N, Lommel B, Maiti M, Minami S, Mistry AK, Mrosek ChM, Pysmenetska I, Rudolph D, Sarmiento LG, Schaffner H, Schädel M, Schausten B, Steiner J, De Heidenreich TT, Uusitalo J, Wegrzecki M, Wiehl N, and Yakusheva V

Abstract

Two short-lived isotopes ^{221}U and ^{222}U were produced as evaporation residues in the fusion reaction ^{50}Ti+^{176}Yb at the gas-filled recoil separator TASCA. An α decay with an energy of E_{α}=9.31(5)  MeV and half-life T_{1/2}=4.7(7)  μs was attributed to ^{222}U. The new isotope ^{221}U was identified in α-decay chains starting with E_{α}=9.71(5)  MeV and T_{1/2}=0.66(14)  μs leading to known daughters. Synthesis and detection of these unstable heavy nuclei and their descendants were achieved thanks to a fast data readout system. The evolution of the N=126 shell closure and its influence on the stability of uranium isotopes are discussed within the framework of α-decay reduced width.

Published
2015
Full Text
View/download PDF

19. 48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr.

Author

Khuyagbaatar J, Yakushev A, Düllmann ChE, Ackermann D, Andersson LL, Asai M, Block M, Boll RA, Brand H, Cox DM, Dasgupta M, Derkx X, Di Nitto A, Eberhardt K, Even J, Evers M, Fahlander C, Forsberg U, Gates JM, Gharibyan N, Golubev P, Gregorich KE, Hamilton JH, Hartmann W, Herzberg RD, Heßberger FP, Hinde DJ, Hoffmann J, Hollinger R, Hübner A, Jäger E, Kindler B, Kratz JV, Krier J, Kurz N, Laatiaoui M, Lahiri S, Lang R, Lommel B, Maiti M, Miernik K, Minami S, Mistry A, Mokry C, Nitsche H, Omtvedt JP, Pang GK, Papadakis P, Renisch D, Roberto J, Rudolph D, Runke J, Rykaczewski KP, Sarmiento LG, Schädel M, Schausten B, Semchenkov A, Shaughnessy DA, Steinegger P, Steiner J, Tereshatov EE, Thörle-Pospiech P, Tinschert K, Torres De Heidenreich T, Trautmann N, Türler A, Uusitalo J, Ward DE, Wegrzecki M, Wiehl N, Van Cleve SM, and Yakusheva V

Abstract

The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results