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39 results on '"Jonson B."'

1. Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near 400A MeV

Author

Boillos, J. M., Cortina-Gil, D., Benlliure, J., Rodríguez-Sánchez, J. L., Alvarez-Pol, H., Atar, L., Aumann, T., Avdeichikov, V. V., Beceiro-Novo, S., Bemmerer, D., Bertulani, C. A., Boretzky, K., Borge, M. J. G., Caamaño, M., Caesar, C., Casarejos, E., Catford, W., Cederkall, J., Chartier, M., Chulkov, L., Cravo, E., Crespo, R. N. P., Dillmann, Iris, Díaz Fernández, P., Elekes, Z., Enders, J., Ershova, O., Estrade, A., Farinon, F., Fraile, L. M., Freer, M., Galaviz Redondo, D., Geissel, H., Gernhäuser, R., Golubev, P., Göbel, K., Hagdahl, J., Heftrich, T., Heil, M., Heine, M., Heinz, A., Henriques, A., Holl, M., Hufnagel, A., Ignatov, A., Johansson, H. T., Jonson, B., Kahlbow, J., Kalantar-Nayestanaki, N., Kanungo, R., Kelic-Heil, A., Knyazev, A., Kröll, T., Kurz, N., Labiche, M., Langer, C., Le Bleis, T., Lemmon, R., Lindberg, S., Machado, J. F. D. C., Marganiec, J., Movsesyan, A., Nacher, E., Najafi, M. A., Nilsson, T., Nociforo, C., Panin, V., Paschalis, S., Perea, A., Petri, M., Pietri, S., Plag, Ralf, Reifarth, R., Ribeiro, G., Rigollet, C., Rossi, D. M., Röder, M., Savran, D., Scheit, H., Simon, H., Sorlin, O., Syndikus, I. J., Taylor, J. T., Tengblad, O., Thies, R., Togano, Y., Vandebrouck, M., Velho, P. J. F., Volkov, V., Wagner, A., Wamers, F., Weick, H., Wheldon, C., Wilson, G. L., Winfield, John Stuart, Woods, P., Yakorev, D., Zhukov, M., Zilges, A., Zuber, K., 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), Grand Accélérateur National d'Ions Lourds (GANIL), 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), and R3B

Subjects
nuclear physics, low and intermediate energy heavy-ion collisions, ddc:530, Física nuclear, nuclear fragmentation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], unstable nuclear induced reactions, nuclear reactions
Abstract

Physical review / C 105(1), 014611 (2022). doi:10.1103/PhysRevC.105.014611, Published by APS, Woodbury, NY

Published
2022
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2. First Accurate Normalization of the $\beta$-delayed $\alpha$ Decay of $^{16}$N and Implications for the $^{12}$C$(\alpha,\gamma)^{16}$O Astrophysical Reaction Rate

Author

Kirsebom, O. S., Tengblad, O., Lica, R., Munch, M., Riisager, K., Fynbo, H. O. U., Borge, M. J. G., Madurga, M., Marroquin, I., Andreyev, A. N., Berry, T. A., Christensen, E. R., Fernández, P. Díaz, Doherty, D. T., Van Duppen, P., Fraile, L. M., Gallardo, M. C., Greenlees, P. T., Harkness-Brennan, L. J., Hubbard, N., Huyse, M., Jensen, J. H., Johansson, H., Jonson, B., Judson, D. S., Konki, J., Lazarus, I., Lund, M. V., Marginean, N., Marginean, R., Perea, A., Mihai, C., Negret, A., Page, R. D., Pucknell, V., Rahkila, P., Sorlin, O., Sotty, C., Swartz, J. A., Sørensen, H. B., Törnqvist, H., Vedia, V., Warr, N., De Witte, H., Grand Accélérateur National d'Ions Lourds (GANIL), 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), Grand Accélérateur National d'Ions Lourds ( GANIL ), 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 ), and 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)

Subjects
ddc:530, Nuclear Physics - Experiment, [ PHYS.NEXP ] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, Nuclear Experiment, Nuclear Physics
Abstract

The $^{12}\text{C}(\alpha,\gamma){}^{16}\text{O}$ reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced $\alpha$ width, $\gamma_{11}$, of the bound $1^-$ level in $^{16}$O is particularly important to determine the cross section. The magnitude of $\gamma_{11}$ is determined via sub-Coulomb $\alpha$-transfer reactions or the $\beta$-delayed $\alpha$ decay of $^{16}$N, but the latter approach is presently hampered by the lack of sufficiently precise data on the $\beta$-decay branching ratios. Here we report improved branching ratios for the bound $1^-$ level [$b_{\beta,11} = (5.02\pm 0.10)\times 10^{-2}$] and for $\beta$-delayed $\alpha$ emission [$b_{\beta\alpha} = (1.59\pm 0.06)\times 10^{-5}$]. Our value for $b_{\beta\alpha}$ is 33% larger than previously held, leading to a substantial increase in $\gamma_{11}$. Our revised value for $\gamma_{11}$ is in good agreement with the value obtained in $\alpha$-transfer studies and the weighted average of the two gives a robust and precise determination of $\gamma_{11}$, which provides significantly improved constraints on the $^{12}$C$(\alpha,\gamma)$ cross section in the energy range relevant to hydrostatic He burning., Comment: 6 pages, 5 figures

Published
2018
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3. Systematic investigation of projectile fragmentation using beams of unstable B and C isotopes

Author

Thies, R, Heinz, A, Adachi, T, Aksyutina, Y, Alcantara-Nunes, J, Altstadt, S, Alvarez-Pol, H, Ashwood, N, Aumann, T, Avdeichikov, V, Barr, M, Beceiro-Novo, S, Bemmerer, D, Benlliure, J, Bertulani, CA, Boretzky, K, Borge, MJG, Burgunder, G, Camano, M, Caesar, C, Casarejos, E, Catford, W, Cederkall, J, Chakraborty, S, Chartier, M, Chulkov, LV, Cortina-Gil, D, Crespo, R, Datta, U, Diaz Fernandez, P, Dillmann, I, Elekes, Z, Enders, J, Ershova, O, Estrade, A, Farinon, F, Fraile, LM, Freer, M, Freudenberger, M, Fynbo, HOU, Galaviz, D, Geissel, H, Gernhauser, R, Gobel, K, Golubev, P, Diaz, DG, Hagdahl, J, Heftrich, T, Heil, M, Heine, M, Henriques, A, Holl, M, Ickert, G, Ignatov, A, Jakobsson, B, Johansson, HT, Jonson, B, Kalantar-Nayestanaki, N, Kanungo, R, Knobel, R, Kroll, T, Krucken, R, Kurcewicz, J, Kurz, N, Labiche, M, Langer, C, Le Bleis, T, Lemmon, R, Lepyoshkina, O, Lindberg, S, Machado, J, Marganiec, J, Maroussov, V, Mostazo, M, Movsesyan, A, Najafi, A, Nilsson, T, Nociforo, C, Panin, V, Paschalis, S, Perea, A, Petri, M, Pietri, S, Plag, R, Prochazka, A, Rahaman, A, Rastrepina, G, Reifarth, R, Ribeiro, G, Ricciardi, MV, Rigollet, C, Riisager, K, Roder, M, Rossi, D, Sanchez del Rio, J, Savran, D, Scheit, H, Simon, H, Sorlin, O, Stoica, V, Streicher, B, Taylor, JT, Tengblad, O, Terashima, S, Togano, Y, Uberseder, E, Van de Walle, J, Velho, P, Volkov, V, Wagner, A, Wamers, F, Weick, H, Weigand, M, Wheldon, C, Wilson, G, Wimmer, C, Winfield, JS, Woods, P, Yakorev, D, Zhukov, MV, Zilges, A, Zuber, K, Collaboration, R, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Grand Accélérateur National d'Ions Lourds (GANIL), 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), R3B Collaboration, KVI - Center for Advanced Radiation Technology, Research unit Nuclear & Hadron Physics, Federal Ministry of Education and Research (Germany), Nuclear Astrophysics Virtual Institute (Germany), Helmholtz Association, Science and Technology Facilities Council (UK), Department of Energy (US), Ministerio de Economía y Competitividad (España), Swedish Research Council, Helmholtz Centre for Heavy Ion Research, National Science Foundation (US), and 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)

Subjects
Physics, Ion beam, 010308 nuclear & particles physics, Fission, Projectile, Nuclear Theory, Fragmentation (computing), Aucun, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, nuclear fragmentation fission radioactive ion beam facilities C10 C12−18 B10−15 isotope, 0103 physical sciences, Neutron, Física nuclear, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment, Excitation, Beam (structure)
Abstract

R. Thies et al.; 9 pags., 7 figs., 1 tab., Background: Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from C10,12-18 and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the epax code is not able to describe the data satisfactorily. Using abrabla07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease abrabla07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study. ©2016 American Physical Society, We thank the FRS and the GSI accelerator staff for their efforts. This work was supported by the Swedish Research Council. O.T. was supported by the Spanish Research Council under project FPA2012-32443, C.A.B. acknowledges support from the U.S. DOE Grant No. DE-FG02-08ER41533 and the U.S. NSF Grant No. 1415656. L.M.F. acknowledges support by the Spanish Research Council under project FPA2013-41267-P and M.R. was supported by GSI (F&E, DR-ZUBE), German BMBF (06DR134I and 05P09CRFN5), the Nuclear Astrophysics Virtual Institute (NAVI, HGF VHVI- 417) and the Helmholtz Association Detector Technology and Systems Platform. T.K. acknowledges support by the German BMBF No. 06DA9040I, No. 05P12RDFN8, and No. 05P15RDFN1. C.W. acknowledges funding by the UK STFC No. ST/E500651/1, while N.A. and M.F. acknowledge funding by the UK STFC No. ST/F011989/1.

Published
2016
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4. Nuclear Halos

Author

Hansen, P G, Jensen, A S, and Jonson, B

Subjects
Nuclear and High Energy Physics, Nuclear Physics
Published
1995
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5. Coulomb breakup of 17 Ne from the view point of nuclear astrophysics

Author

Marganiec, J., Aksouh, F., Aksyutina, Y., Álvarez-Pol, H., Aumann, T., Beceiro, S., Bertulani, C., Boretzky, K., García Borge, María José, Chartier, M., Chatillon, A., Chulkov, L., Cortina-Gil, D., Egorova, I., Emling, H., Ershova, O., Forssén, C., Fraile, Luis M., Fynbo, H.O.U., Galaviz, D., Geissel, H., Grigorenko, L., Heil, M., Hoffmann, D.H.H., Hoffmann, J., Johansson, H., Jonson, B., Karagiannis, C., Kiselev, O., Kratz, J.V., Kulessa, R., Kurz, N., Langer, C., Lantz, M., Larsson, K., Le Bleis, T., Lemmon, R., Lindahl, A., Litvinov, Yu. A., Mahata, K., Müntz, C., Nilsson, T., Nociforo, C., Nyman, G., Ott, W., Panin, V., Parfenova, Yu., Paschalis, S., Perea, Ángel, Plag, R., Reifarth, R., Richter, A., Rodríguez Tajes, C., Rossi, D., Schrieder, G., Shulgina, N., Simon, H., Stroth, J., Sümmerer, K., Taylor, J., Tengblad, Olof, Tengborn, E., Wamers, F., Weick, H., Wimmer, C., Zhukov, M., Federal Ministry of Education and Research (Germany), European Commission, and Helmholtz International Center for FAIR

Subjects
Nuclear physics, Physics, CNO cycle, Ion beam, Coulomb, Nuclear astrophysics, Halo nucleus, rp-process, Atomic physics, Breakup, Nucleon
Abstract

6 pags., 5 figs. -- XII International Symposium on Nuclei in the Cosmos, August 5-12, 2012, Cairns, Australia, By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p, γ) 17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section σCoul has been determined, which then will be converted into a photo-absorption cross section σphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress., This project was supported by the German Federal Ministry for Education and Research (BMBF), EU(EURONS), EMMI-GSI, and HIC for FAIR

Published
2012
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6. Searching for the sup 5 H resonance for the t+n+n system

Author

Meister, M, Aumann, T, García-Borge, M J, Chulkov, L V, Elze, T W, Emling, H, Geissel, H, Hellström, M, Jonson, B, Kratz, J V, Kulessa, R, Leifels, Y, Markenroth, K G, Münzenberg, G, Nickel, F, Nilsson, T, Nyman, G H, Pribora, V N, Richter, A, Riisager, K, Scheidenberger, C, Schrieder, G, Simon, H, and Tengblad, O

Subjects
Nuclear Theory, Nuclear Experiment, Nuclear Physics
Abstract

The unbound hydrogen isotopes sup 4 sup , sup 5 H have been studied in the one-proton knockout channel of sup 6 He (240 MeV/u) impinging on a carbon target. The triton fragments originating from this channel were detected in coincidence with neutrons. Relative energy spectra as well as energy and angular correlations have been studied for the t+n and t+n+n systems. The analysis of the energy and angular correlations by the method of hyperspherical harmonic expansion allows to determine the relative weights of the most relevant partial waves in the three-body t+n+n final state. It is shown that the neutrons to a large extent occupy the p-shell and that the I suppi = 1/2 sup + state is strongly populated as expected for the sup 5 H ground state. No evidence for a narrow resonance in the t+n+n system is obtained, instead a broad structure peaked at 3 MeV above the threshold with about 6 MeV as a full width at half maximum is observed. The two-body t+n system reveals a resonance compatible with earlier results for sup 4 H.

Published
2003

7. Three-body correlations in Borromean halo nuclei

Author

Marqués, F. M., Labiche, M., Orr, N. A., Angélique, J. C., Axelsson, L., Benoit, B., Bergmann, U. C., García Borge, María José, Catford, W.N., Chappell, S. P. G., Clarke, N. M., Costa, G., Curtis, N., D’Arrigo, A., Brennand, E. D., Oliveira Santos, F. D., Dorvaux, O., Fazio, G., Freer, M., Fulton, B. R., Giardina, G., Grévy, S., Guillemaud-Mueller, D., Hanappe, F., Heusch, B., Jonson, B., Le Brun, C., Leenhardt, S., Lewitowicz, M., López, M. J., Markenroth, K., Mueller, A. C., Nilsson, T., Ninane, A., Nyman, G., Piqueras, Inmaculada, Riisager, K., Saint-Laurent, M. G., Sarazin, F., Singer, S. M., Sorlin, O., Stuttge, L., Góes Brennand, E. D., Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), 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), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, [PACS]Properties of specific nuclei listed by mass ranges: 6 ≤ A ≤ 19, 010308 nuclear & particles physics, Nuclear Theory, FOS: Physical sciences, Few-body systems, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, Dissociation (chemistry), 3. Good health, Nuclear physics, Combined treatment, 0103 physical sciences, [PACS]Few-body systems, Halo, [PACS]Nucleon distributions and halo features, Nuclear Experiment (nucl-ex), 010306 general physics, 6 ≤ A ≤ 19 [[PACS]Properties of specific nuclei listed by mass ranges], Nuclear Experiment, [PACS]Nuclear reactions involving few-nucleon systems
Abstract

5 pages, 4 figures.--PACS nrs.: 25.10.+s; 21.10.Gv; 21.45.+v; 27.20.+n.--ArXiv pre-print available at: http://arxiv.org/abs/nucl-ex/0101004v2., Three-body correlations in the dissociation of two-neutron halo nuclei are explored using a technique based on intensity interferometry and Dalitz plots. This approach provides for the combined treatment of both the n-n and core-n interactions in the exit channel. As an example, the breakup of Be-14 into Be-12 + n + n by Pb and C targets has been analyzed and the halo n-n separation extracted. Evidence for a finite delay between the emission of the neutrons in the reaction on the C target was observed and is attributed to Be-13 resonances populated in sequential breakup., This work was funded under the auspices of the IN2P3-CNRS (France) and EPSRC (United Kingdom). Additional support from the ALLIANCE program (Ministère des Affaires Etrangères and British Council), the Human Capital and Mobility Program of the European Community (Contract No. CHGE-CT94-0056), and the GDR Noyaux Exotiques (CNRS-CEA) is also acknowledged.

Published
2001
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8. Continuum excitations in $^{6}He$

Author

Aumann, T., Aleksandrov, D., Axelsson, L., Baumann, T., Borge, M. J. G., Chulkov, L. V., Cub, J., Dostal, W., Eberlein, B., Elze, Th W., Emling, H., Geissel, H., Goldberg, V. Z., Golovkov, M., Grünschloß, A., Hellström, M., Hencken, K., Holeczek, J., Holzmann, R., Jonson, B., Korshenninikov, A. A., Kratz, J. V., Kraus, G., Kulessa, R., Leifels, Y., Leistenschneider, A., Leth, T., Ivan Mukha, Münzenberg, G., Nickel, F., Nilsson, T., Nyman, G., Petersen, B., Pfützner, M., Richter, A., Riisager, K., Scheidenberger, C., Schrieder, G., Schwab, W., Simon, H., Smedberg, M. H., Steiner, M., Stroth, J., Surowiec, A., Suzuki, T., Tengblad, O., and Zhukov, M. V.

Subjects
Nuclear Physics
Published
1999

9. Exotic molecular and halo states in ${12,14}Be$

Author

Freer, M., Orr, N.A., Labiche, M., Marqués, F.M., Angélique, J.C., Axelsson, L., Benoit, B., Bergmann, U., Borge, M J G., Catford, W N., Chappell, S P G., Clarke, N M., Costa, G., Curtis, N., D'Arrigo, A., D'Oliviera, F., De Goes-Brennard, E., Dorvaux, O., Fulton, B R., Gardina, G., Gregori, C., Grevy, S., Guillemaud-Mueller, D., Hanappe, F., Heusch, B., Jonson, B., Kelly, G., Le Brun, C., Leenhardt, S., Lewitowicz, M., Markenroth, K., Motta, M., Mueller, A C., Murgatroyd, J T., Nilsson, T., Ninane, A., Nyman, G., Piqueras, I., Riisager, K., Saint-Laurent, M.G., Sarazin, F., Singer, S., Sorlin, O., Stuttge, L., Watson, D L., Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), 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), Sherrill B.M., Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Physics
Abstract

International audience; The two nuclei 12Be and 14Be have been studied using breakup reactions on p, 12C and 208Pb targets. The decay of 12Be into two helium clusters (6He+6He and 4He+8He) was observed from a series of excited states between 10 and 25 MeV, with spins in the range 4+ to 8+. The single neutron angular distributions for 14Be exhibit the narrow forward peak characteristic of a halo. The widths of these distributions in coincidence with 12Be fragments are ΓL = 78±6 and 80±1 MeV/c for breakup on carbon and lead.

Published
1998
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10. Invariant mass spectrum and $\alpha$-n correlation function studied in the fragmentation of $^{6}He$ on a carbon target

Author

Aleksandrov, D V, Aumann, T, Axelsson, L, Baumann, T, García-Borge, M J, Chulkov, L V, Cub, J, Dostal, W, Eberlein, B, Elze, T W, Emling, H, Geissel, H, Goldberg, V Z, Golovkov, M S, Grünschloss, A, Hellström, M, Holeczek, J, Holzmann, R, Jonson, B, Korsheninnikov, A A, Kratz, J V, Kraus, G, Kulessa, R, Leifels, Y, Leistenschneider, A, Leth, T E, Mukha, I, Münzenberg, G, Nickel, F, Nilsson, T, Nyman, G H, Petersen, B, Pfützner, M, Richter, A, Riisager, K, Scheidenberger, C, Schrieder, G, Schwab, W, Simon, H, Smedberg, M H, Steiner, M, Stroth, J, Surowiec, A, Suzuki, T, Tengblad, O, and Zhukov, M V

Subjects
Nuclear Physics
Published
1997

11. Large spin alignment of the unbound $^{5}He$ fragment after fragmentation of 240 MeV/u $^{6}He$

Author

Chulkov, L V, Aumann, T, Aleksandrov, D V, Axelsson, L, Baumann, T, García-Borge, M J, Collatz, R, Cub, J, Dostal, W, Eberlein, B, Elze, T W, Emling, H, Geissel, H, Goldberg, V Z, Golovkov, M S, Grünschloss, A, Hellström, M, Holeczek, J, Holzmann, R, Jonson, B, Korsheninnikov, A A, Kratz, J V, Kraus, G, Kulessa, R, Leifels, Y, Leistenschneider, A, Leth, T E, Mukha, I, Münzenberg, G, Nickel, F, Nilsson, T, Nyman, G H, Petersen, B, Pfützner, M, Richter, A, Riisager, K, Scheidenberger, C, Schrieder, G, Schwab, W, Simon, H, Smedberg, M H, Steiner, M, Stroth, J, Surowiec, A, Suzuki, T, and Tengblad, O

Subjects
Nuclear Physics
Published
1997

12. Study of the unstable nucleus $^{10}$Li in stripping reactions of the radioactive projectiles $^{11}$Be and $^{11}$Li

Author

Zinser, M, Humbert, F, Nilsson, T, Schwab, W, Blaich, T, García-Borge, M J, Chulkov, L V, Elze, T W, Emling, H, Freiesleben, H, Geissel, H, Grimm, K, Guillemaud-Müller, D, Hansen, P G, Holzmann, R, Irnich, H, Jonson, B, Keller, J G, Klingler, H, Kratz, J V, Kulessa, R, Lambrecht, D, Leifels, Y, Magel, A, Mohar, M F, Müller, A C, Münzenberg, G, Nickel, F, Nyman, G H, Richter, A, Riisager, K, Scheidenberger, C, Schrieder, G, Sherrill, B M, Simon, H, Stelzer, K, Stroth, J, Tengblad, O, Trautmann, W, Wajda, E, and Zude, E

Subjects
Nuclear Physics
Published
1995

13. Neutron angular distributions from the breakup of $^{19}$C

Author

Angélique, J C, Axelsson, L, Bizard, G, Catford, W N, Clarke, N M, Costa, G, Freer, M, Grévy, S, Guillemaud-Müller, D, Gyapong, G J, Hanappe, F, Heusch, B, Jonson, B, Lebrun, C, Lecolley, F R, Lefèbvres, F, Lewitowicz, M, Liegard, E, Marqués, F M, Martínez, G, Müller, A C, Nilsson, T, Ninane, A, Nyman, G H, Orr, N A, Peterson, B M, Pougheon, F, Riisager, K, Saint-Laurent, M G, Schutz, Y, Smedberg, M H, Sorlin, O, Stuttgé, L, and Warner, D D

Subjects
Nuclear Physics
Published
1995

14. Clarification of the Three-Body Decay of 12C (12.71 MeV)

Author

Fynbo, H. O. U., Prezado, Y., Bergmann, U. C., Borge, M. J. G., Dendooven, Peter, Huang, Wenxue, Huikari, Jussi, Jeppesen, H., Jones, Peter, Jonson, B., Meister, M., Nyman, G., Riisager, K., Tengblad, O., Vogelius, I. S., Wang, Youbao, Weissman, L., Rolander, K. Wilhelmsen, and Äystö, Juha

Subjects
nuclear physics, Nuclear Physics - Experiment, ydinfysiikka
Abstract

Using β decays of a clean source of 12 N produced at the IGISOL facility, we have measured the breakup of the 12 C (12.71 MeV) state into three α particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed. peerReviewed

Published
1991

15. Nuclear Structure of 12C from Break-up Studies in Complete Kinematics.

Author

Alcorta, M., Borge, M. J. G., Cubero, M., Dominguez-Reyes, R., Fraile, L., Fulton, B., Fynbo, H. O. U., Galaviz, D., Hyldegaard, S., Jeppesen, H., Jonson, B., Kirsebom, O., Madurga, M., Maira, A., Muñoz, A., Nilsson, T., Nyman, G., Obradors, D., Perea, A., and Riisager, K.

Subjects
NUCLEAR structure, NUCLEAR reactions, NUCLEAR energy, ALPHA rays, NUCLEAR physics
Abstract

A complete kinematics study of the 10B(3He,pααα) and 11B(3He,dααα) reactions has been performed to study the multi-particle break-up of 12C resonances above the triple-alpha threshold. Four-particle coincidence detection gives us complete information on the direction and energy of the individual alpha particles from the decay of 12C, allowing us to extract new information on the structure of 12C which we shall present in this contribution. We have observed gamma de-excitation of the T = 1 15.11 MeV resonance using charged particle detectors, and have constructed Dalitz plots of the individual resonances in 12C using the complete kinematics information of the alpha particles which come from their break-up. [ABSTRACT FROM AUTHOR]

Published
2009
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16. Shell Closure N = 16 in 24O.

Author

Nociforo, C., Kanungo, R., Prochazka, A., Aumann, T., Boutin, D., Cortina-Gil, D., Davids, B., Diakaki, M., Farinon, F., Geissel, H., Gernhäuser, R., Gerl, J., Janik, R., Jonson, B., Kindler, B., Knöbel, R., Krücken, R., Lantz, M., Lenske, H., and Litvinov, Yu. A.

Subjects
NUCLEAR physics, ISOTOPES, SPECTRUM analysis, NEUTRONS, ION bombardment
Abstract

Advanced nuclear structure models predict the presence of the shell closures N = 14, 16 in neutron-rich O isotopes rather than N = 20. Spectroscopic investigations performed at the neutron drip line have recently confirmed such predictions showing that the 24O is a doubly magic nucleus (Z = 8, N = 16). Predictions within the shell model calculation for the 23,24O ground state have been confirmed measuring their spectroscopic factors. Results obtained in one-neutron removal reactions performed by using in-flight radioactive ion beams produced at the Fragment Separator FRS of GSI are reported. [ABSTRACT FROM AUTHOR]

Published
2009
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17. GROUND-STATE PROPERTIES OF NEUTRON-RICH NUCLEI IN THE SD-SHELL.

Author

CORTINA-GIL, D., FERNANDEZ-VAZQUEZ, J., MARKENROTH, K., ATTALLAH, F., BAUMANN, T., BENLLIURE, J., BORGE, M. J. G., CHULKOV, L., FORSSÉN, C., FRAILE, L. M., GEISSEL, H., GERL, J., ITHASHI, K., JANIK, R., JONSON, B., KARLSSON, S., MANDAL, S., MEISTER, M., MOCKO, X., and OHTSUBO, T.

Subjects
NEUTRONS, HEAVY nuclei, COULOMB potential, PROTONS, NUCLEAR structure, NUCLEAR physics
Published
2002

18. One-neutron knockout of 23O.

Author

Cortina-Gil, D., Fernandez-Vazquez, J., Aumann, T., Baumann, T., Benlliure, J., Borge, M. J. G., Chulkov, L. V., Datta Pramanik, U., Forssén, C., Fraile, L. M., Geissel, H., Gerl, J., Hammache, F., Itahashi, K., Janik, R., Jonson, B., Mandal, S., Markenroth, K., Meister, M., and Mocko, M.

Subjects
NEUTRONS, ISOTOPES, PARTICLES (Nuclear physics), NUCLEAR physics, PHYSICS
Abstract

Breakup reactions were used to study the ground-state configuration of the neutron-rich isotope 23O. The 22O fragments produced in one-nucleon removal from 23O at 938 MeV/nucleon in a carbon target were detected in coincidence with de-exciting γ rays, allowing to discern between 22O ground-state and excited-states contributions. From the comparison of exclusive experimental momentum distributions for the one-neutron removal channel to theoretical momentum distributions calculated in an Eikonal model for the knockout process, and spin and parity assignment of Iπ = 1/2+ was deduced for the 23O ground state. This result solved the existent experimental discrepancy. [ABSTRACT FROM AUTHOR]

Published
2005
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19. Light dripline nuclei

Author

Jonson, B.

Subjects
*PARTICLES (Nuclear physics), *NUCLEAR fission, *NUCLEAR reactions, *NUCLEAR physics
Abstract

Some recent result for light dripline nuclei are reviewed. The main emphasis is put on nuclei with neutron numbers N = 6, 7 and 8. [Copyright &y& Elsevier]

Published
2004
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20. Dripline Nuclei.

Author

Jonson, B.

Subjects
*NUCLEAR physics, *PARTICLES (Nuclear physics)
Abstract

A review of some recent experimental studies of dripline nuclei is given. The main emphasis is devoted to light nulcei and especially to the occurrence of halo states. [ABSTRACT FROM AUTHOR]

Published
2002
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21. New targets for on-line mass separation of nuclei formed in 600 MeV proton and 910 Mev $^{3}$He reactions

Author

Bjørnstad, T, Carraz, L C, Gustafsson, Hans Åke, Hagberg, E, Heinemeier, J, Jonson, B, Jonsson, O C, Lindfors, V, Mattsson, S, and Ravn, H L

Subjects
Nuclear physics, Isotope, Fragmentation (mass spectrometry), Proton, Chemistry, Projectile, General Engineering, Spallation, Atomic physics, Detectors and Experimental Techniques, Mass separation
Abstract

The performance of the previously reported UC2-graphite cloth, VC, la and Pb targets, as well as the newly developed ThC2-graphite, UC2-graphite, ScC2-graphite, and CaB6 targets is discussed. Production-yield curves for the elements Li, Na, Ar, K, Ga, Rb, In, Cs, Hg, Tl and Fr are given for 600 MeV protons and 910 MeV 3He. It is shown that the latter projectile gives higher yields for the neutron-deficient isotopes produced in fragmentation and spallation processes.

Published
1980

23. The decay of a T$_{Z}$ = -2 nucleus: argon-32

Author

Hagberg, E, Hansen, P G, Hardy, J C, Huck, A, Jonson, B, Mattsson, S, Ravn, H L, Tidemand-Petersson, P, and Walter, G

Subjects
Nuclear Theory, Nuclear Experiment, Nuclear Physics
Abstract

The masses of members of an isobaric multiplet are given by the isobaric-multiplet-mass equation. In order to test the equation for a T=2 multiplet, the authors have observed beta -delayed proton decay in /sup 32/Ar. Proton spectra from the populated /sup 32/Cl T=2 analogue state gives the mass defect of the 0/sup +/ state. (13 refs).

Published
1977

24. Particle unstable excited states in /sup 9/Be: influence of beta recoil and width on delayed particle spectra

Author

Nyman, G H, Azuma, R E, Jonson, B, Kratz, K L, Larsson, P O, Mattsson, S, and Ziegert, W

Subjects
Nuclear Theory, Physics::Accelerator Physics, Nuclear Experiment, Nuclear Physics
Abstract

The light nucleus /sup 9/Be has been studied through the emission of beta-delayed neutrons and alpha particles from /sup 9/Li. The activity is produced at the ISOLDE facility in fragmentation reactions induced either by 600 MeV proton or 910 MeV /sup 3/He beams from the CERN Synchro-cyclotron. After mass separation neutron spectra are recorded using /sup 3/He-filled proportional counters, while surface barrier detectors are used for the spectroscopy of alpha particles. Effects on the spectrum shape induced by recoil and polarization phenomena as well as large widths of the intermediate states are discussed. (14 refs).

Published
1981

26. The strongly deformed nucleus /sup 100/Sr

Author

Mattsson, S, Azuma, R E, Gustafsson, Hans Åke, Hansen, P G, Jonson, B, Lindfors, V, Nyman, G H, Ragnarsson, I, Ravn, H L, and Schardt, D

Subjects
Nuclear Physics
Abstract

Experiments on the nucleus /sup 100/Sr are reviewed. The activity was produced by fission with 600 MeV protons on a uranium target and after mass separation studied by gamma-ray and conversion-electron spectroscopy and by nanosecond lifetime measurements. The theoretical implications of these results are discussed on the basis of a Nilsson- Strutinsky calculation. (14 refs).

Published
1981

27. Comparative yields of alkali elements and thallium from uranium irradiated with high-energy protons, /sup 3/He and /sup 12/C

Author

Gustafsson, Hans Åke, Bjørnstad, T, Jonson, B, Jonsson, O C, Lindfors, V, Mattsson, S, Poskanzer, A M, Ravn, H L, and Schardt, D

Subjects
Nuclear Physics
Abstract

Mass-separated ion beams of the alkali elements Na, K, and Fr, and of the element Tl are produced by bombarding a uranium target with 600 Me V protons, 890 MeV /sup 3/He/sup 2+/, and 936 MeV /sup 12/C/sup 4+/. Isotopic production yields are reported. In the case of the /sup 12/C beam these are thick target yields. Absolute cross-sections for the proton-beam data were deduced by normalizing the delay-time corrected yield curves to measured cross-sections. For products farthest away from stability the /sup 3/He/sup 2+/ beam generally gives the highest yields. (17 refs).

Published
1981

29. Study of the charge radii of the stable lead isotopes

Author

Borchert, G L, Hansen, P G, Jonson, B, McGrory, J B, Ravn, H L, Schult, O W B, and Speth, J

Subjects
Nuclear Physics
Abstract

Isotope shifts have been measured of the K alpha /sub 1/ X-ray lines emitted after photo ionization of /sup 204/Pb, /sup 206/Pb, /sup 207 /Pb and /sup 208/Pb samples. The results are compared with theoretical values for delta (r/sup 2/) calculated with a microscopic model. The X-ray shift data are also compared with optical data and the nuclear parameters lambda derived from electron scattering results. (33 refs).

Published
1981

30. Direct experimental evidence for strong admixture of different parity states in 11Li

Author

Simon, H., Aleksandrov, D., Aumann, T., Axelsson, L., Baumann, T., Borge, M. J. G., Chulkov, L. V., Collatz, R., Cub, J., Dostal, W., Eberlein, B., Elze, Th W., Emling, H., Geissel, H., Grunschloss, A., Hellström, M., Holeczek, J., Holzmann, R., Jonson, B., Kratz, J. V., Kraus, G., Kulessa, R., Leifels, Y., Leistenschneider, A., Leth, T., Ivan Mukha, Münzenberg, G., Nickel, F., Nilsson, T., Nyman, G., Petersen, B., Pfützner, M., Richter, A., Riisager, K., Scheidenberger, C., Schrieder, G., Schwab, W., Smedberg, M. H., Stroth, J., Surowiec, A., Tengblad, O., and Zhukov, M. V.

Subjects
Nuclear Physics

31. Sizeable beta-strength in 31Ar (β3p) decay.

Author

Koldste, G.T., Blank, B., Borge, M.J.G., Briz, J.A., Carmona-Gallardo, M., Fraile, L.M., Fynbo, H.O.U., Giovinazzo, J., Johansen, J.G., Jokinen, A., Jonson, B., Kurturkian-Nieto, T., Nilsson, T., Perea, A., Pesudo, V., Picado, E., Riisager, K., Saastamoinen, A., Tengblad, O., and Thomas, J.-C.

Subjects
*PARTICLE decays, *SENSITIVITY analysis, *PARTICLES (Nuclear physics), *STRENGTH of materials, *EXCITATION energy (In situ microanalysis), *NUCLEAR physics
Abstract

We present for the first time precise spectroscopic information on the recently discovered decay mode β -delayed 3p-emission. The detection of the 3p events gives an increased sensitivity to the high energy part of the Gamow–Teller strength distribution from the decay of 31 Ar revealing that as much as 30% of the strength resides in the β 3p-decay mode. A simplified description of how the main decay modes evolve as the excitation energy increases in 31 Cl is provided. [ABSTRACT FROM AUTHOR]

Published
2014
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32. Momentum profile analysis in one-neutron knockout from Borromean nuclei

Author

Aksyutina, Yu., Aumann, T., Boretzky, K., Borge, M.J.G., Caesar, C., Chatillon, A., Chulkov, L.V., Cortina-Gil, D., Datta Pramanik, U., Emling, H., Fynbo, H.O.U., Geissel, H., Ickert, G., Johansson, H.T., Jonson, B., Kulessa, R., Langer, C., LeBleis, T., Mahata, K., and Münzenberg, G.

Subjects
*ANGULAR momentum (Mechanics), *NEUTRONS, *NUCLEAR physics, *WAVE functions, *FUNCTIONAL analysis, *SQUARE root
Abstract

Abstract: One-neutron knockout reactions from Borromean nuclei are analyzed using a profile function analysis technique. The profile function, which is derived as the square root of the variance of the measured fragment + neutron momenta as a function of their relative energy, is shown to be very sensitive to the angular momentum of the knocked out neutron. Three cases are studied here: 7He, where the profile function analysis shows a presence of component in the 8He ground-state wave-function, 10Li, where the presence of a 11(2)% d-wave contribution to the relative energy spectrum above 1.5 MeV is found and, finally, the presence of a major s contribution around 0.5 MeV relative energy in the 13Be case and that the observed decay to the 12Be state originates in a d state in 13Be. [Copyright &y& Elsevier]

Published
2013
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33. Improved Limit on Direct a Decay of the Hoyle State.

Author

Kirsebom, O. S., Alcorta, M., G. Borge, M. J., Cubero, M., Diget, C. Aa., Fraile, L. M., Fulton, B. R., U. Fynbo, H. O., Galaviz, D., Jonson, B., Madurga, M., Nilsson, T., Nyman, G., Riisager, K., Tengblad, O., and Turrión, M.

Subjects
*RADIOACTIVE decay, *NUCLEAR reactions, *GROUND state (Quantum mechanics), *ASTROPHYSICS, *NUCLEAR physics, *PARTICLES (Nuclear physics), *KINEMATICS
Abstract

The current evaluation of the triple-α reaction rate assumes that the a decay of the 7.65 MeV, 0+ state in 12C, commonly known as the Hoyle state, proceeds sequentially via the ground state of 8Be. This assumption is challenged by the recent identification of two direct a-decay branches with a combined branching ratio of 17(5)%. If correct, this would imply a corresponding reduction in the triple-a reaction rate with important astrophysical consequences. We have used the 11B(3He, d) reaction to populate the Hoyle state and measured the decay to three a particles in complete kinematics. We find no evidence for direct α-decay branches, and hence our data do not support a revision of the triple-α reaction rate. We obtain an upper limit of 5 X 10-3 on the direct α decay of the Hoyle state at 95% C.L., which is 1 order of magnitude better than a previous upper limit. [ABSTRACT FROM AUTHOR]

Published
2012
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34. Precise and accurate determination of the 8B decay spectrum.

Author

Kirsebom, O. S., Hyldegaard, S., Alcorta, M., Borge, M. J. G., Büscher, J., Eronen, T., Fox, S., Fulton, B. R., Fynbo, H. O. U., Hultgren, H., Jokinen, A., Jonson, B., Kankainen, A., Karvonen, P., Kessler, T., Laird, A., Madurga, M., Moore, I., Nyman, G., and Penttilä, H.

Subjects
*SOLAR neutrinos, *NEUTRINOS, *PARTICLES (Nuclear physics), *SOLAR radiation, *NUCLEAR physics
Abstract

Accurate measurements of the 8B neutrino spectrum are important for the interpretation of solar neutrino data. Experimentally, the 8B neutrino spectrum can be obtained from the measurement of the β-delayed α spectrum. We report on an α-α coincidence measurement performed at the IGISOL facility in Jyväskylä, Finland. Our measurement allows extensive cross-checks to be performed and gives a more intense neutrino spectrum at high energies compared to the present standard. The deviation reaches 4% at the end point of the spectrum. Below 11 MeV, the deviation is less than 1%. [ABSTRACT FROM AUTHOR]

Published
2011
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35. Study of β-delayed 3-body and 5-body breakup channels observed in the decay of 11Li

Author

Madurga, M., Borge, M.J.G., Angelique, J.C., Bao, L., Bergmann, U., Bută, A., Cederkäll, J., Diget, C.Aa., Fraile, L.M., Fynbo, H.O.U., Jeppesen, H.B., Jonson, B., Maréchal, F., Marqués, F.M., Nilsson, T., Nyman, G., Perrot, F., Riisager, K., Tengblad, O., and Tengborn, E.

Subjects
*MONTE Carlo method, *SPECTRUM analysis, *NUCLEAR physics, *PHYSICS
Abstract

Abstract: The β-delayed charged particle emission from 11Li has been studied with emphasis on the three-body nα 6He and five-body 2α3n channels from the 10.59 and 18.15 MeV states in 11Be. Monte Carlo simulations using an R-matrix formalism lead to the conclusion that the A He resonance states play a significant role in the break-up of these states. The results exclude an earlier assumption of a phase-space description of the break-up process of the 18.15 MeV state. Evidence for extra sequential decay paths is found for both states. [Copyright &y& Elsevier]

Published
2008
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36. Properties of the 12C 10 MeV state determined through β-decay

Author

Diget, C.Aa., Barker, F.C., Borge, M.J.G., Cederkäll, J., Fedosseev, V.N., Fraile, L.M., Fulton, B.R., Fynbo, H.O.U., Jeppesen, H.B., Jonson, B., Köster, U., Meister, M., Nilsson, T., Nyman, G., Prezado, Y., Riisager, K., Rinta-Antila, S., Tengblad, O., Turrion, M., and Wilhelmsen, K.

Subjects
*NUCLEAR reactions, *COLLISIONS (Nuclear physics), *NUCLEAR physics, *COMPOUND nucleus, *ANGULAR correlations (Nuclear physics)
Abstract

Abstract: The β-delayed triple-α particle decay of 12B has been measured with a setup that favours coincidence detection. A broad state in 12C, previously reported around 10 MeV, has been seen and its properties determined through R-matrix analysis of the excitation spectrum. The spin and parity are . Interference between this state and the Hoyle state at 7.654 MeV has a marked influence on the spectrum. The coupling between the two states makes it difficult to determine the resonance energy. [Copyright &y& Elsevier]

Published
2005
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37. The β-decay of 9Li to the high lying states in 9Be

Author

Prezado, Y., Bergmann, U.C., Borge, M.J.G., Cerdekäll, J., Fraile, L.M., Fynbo, H.O.U., Jeppesen, H., Jonson, B., Meister, M., Nyman, G., Riisager, K., Tengblad, O., Nilsson, T., Weissmann, L., and Wilhelmsen, K.

Subjects
*COINCIDENCE, *NUCLEAR energy, *SPECTRUM analysis, *NUCLEAR physics
Abstract

Mirror β-transitions should have similar strengths as long as binding energy, Coulomb energy and other explicitly breaking effects are small. However, large β-decay asymmetries have been observed in the decay of 9C [Phys. Rev. C 37 (1988) 766] and the decay of its mirror nucleus 9Li [Nucl. Phys. A 510 (1990) 189]. These asymmetries could be the indication of structural differences between mirror states. We have focussed on the beta-decays of 9C and 9Li to the high lying region (between 11-12 MeV) in the daughter nuclei 9B and 9Be. The difficulty in the study of these decays is that they are accompanied by the emission of three particles and one needs to determine the breakup mechanism to extract information about the position, width and feeding of the states. The β-decays of 9C [Nucl. Phys. A 692 (2001) 427] and 9Li [Phys. Lett. B. 576 (2003) 22] to the high lying region of the daughter nuclei have been remeasured with setups that allow the study of the complete kinematics of the processes and, hence, the breakup mechanism of the states in the daughter nuclei can be determined. The most recent experiments on 9C [Nucl. Phys. A 692 (2001) 427, Phys. Rev. C 61 (2000) 064310] gave BGT values of 1.58(16) and 1.20 (15) for the transition 9C → 9B (12.2 MeV) whereas the only early determination for 9Li→ 9Be (11.81 MeV) [Nucl. Phys. A 510 (1990) 189] gave 5.6 (1.2). The experiments on 9C employed coincidence detection of charged particles thereby allowing a detailed analysis, whereas the older 9Li experiment only included singles spectra. The only previous 9Li experiment where α-particle coincidences were measured [Nucl. Phys. A 366 (1981) 449] did not have sufficient angular resolution and no detailed analysis of the breakup mechanism was performed. [Copyright &y& Elsevier]

Published
2004
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38. Nuclear structure of light exotic nuclei from break-up reactions

Author

Cortina, D., Fernandez-Vazquez, J., Aumann, T., Baumann, T., Benlliure, J., Borge, M.J.G., Chulkov, L.V., Datta Pramanik, U., Forssén, C., Fraile, L.M., Geissel, H., Gerl, J., Hammache, F., Itahashi, K., Janik, R., Jonson, B., Mandal, S., Markenroth, K., Meister, M., and Mocko, M.

Subjects
*NUCLEAR structure, *NUCLEAR physics, *PARTICLES (Nuclear physics), *ANNIHILATION reactions
Abstract

One-nucleon removal reactions at relativistic energies have been used as a spectroscopic tool to characterise the ground state properties of several neutron-rich isotopes in the sd-shell. Using the FRS at GSI, the longitudinal momentum distributions of the emerging fragments after one-nucleon removal were measured. The relative contributions of the remaining fragments in their ground and excited states have been determined from measurements of γ rays in coincidence with the longitudinal momentum distributions. In particular the breakup of 23O has been investigated. The interpretation of our measurements, in the framework of a simple theoretical model, favours a spin and parity assignment of 1/2+ for the 23O ground state in agreement with shell model predictions. [Copyright &y& Elsevier]

Published
2004
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39. Nuclear and Coulomb breakup of <f>8</f>B

Author

Cortina-Gil, D., Fernandez-Vazquez, J., Attallah, F., Baumann, T., Benlliure, J., Borge, M.J.G., Chulkov, L., Forssén, C., Fraile, L.M., Geissel, H., Gerl, J., Itahashi, K., Janik, R., Jonson, B., Karlsson, S., Lenske, H., Mandal, S., Markenroth, K., Meister, M., and Mocko, M.

Subjects
*NUCLEAR excitation, *NUCLEAR physics
Abstract

One-proton removal reactions of 936 MeV/u 8B have been studied with carbon and lead as breakup targets. Using the FRS at GSI, the longitudinal momentum distributions of the 7Be fragments and the one-proton removal cross section of 8B were measured. The relative contributions of the breakup channels leading to 7Be in its ground state and excited state at 429 keV (7Be&ast;) have been determined from measurements of γ rays in coincidence with the fragments from the one-proton removal reaction. The experimental breakup data are discussed in the context of a theoretical (α+3He+p) three-body model. The combined data from the two targets allow a determination of the weight of the 7Be&ast; component in the 8B ground state wave function as (13.3±2.2%) [Copyright &y& Elsevier]

Published
2003
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