Search

Your search keyword '"M. Hellstroem"' showing total 4 results
Start Over Author "M. Hellstroem"
4 results on '"M. Hellstroem"'

1. Dipole response of neutron-rich Sn isotopes

Author

Y. Leifels, R. Kulessa, G. Surówka, M. Fallot, R. Palit, Thomas Aumann, W. Walus, P. Adrich, U. Datta Pramanik, K. L. Jones, D. Cortina-Gil, M. Hellstroem, K. Sümmerer, C. Nociforo, H. Emling, J. V. Kratz, Stefan Typel, Th. W. Elze, K. Boretzky, A. Klimkiewicz, Hans Geissel, and Herbert A. Simon

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Nuclear Theory, Transition dipole moment, Neutron, Coulomb excitation, Electric dipole transition, Atomic physics, Nuclear Experiment, Nucleon, Resonance (particle physics), Excitation
Abstract

The neutron-rich isotopes 129–133Sn were studied in a Coulomb excitation experiment at about 500 AMeV using the FRS-LAND setup at GSI. From the exclusive measurement of all projectile-like particles following the excitation and decay of the projectile in a high-Z target, the energy differential cross section can be extracted. At these beam energies dipole transitions are dominating, and within the semi-classical approach the Coulomb excitation cross sections can be transformed into photoabsorption cross sections. In contrast to stable Sn nuclei, a substantial fraction of dipole strength is observed at energies below the giant dipole resonance (GDR). For 130Sn and 132Sn this strength is located in a peak-like structure around 10 MeV excitation energy and exhibits a few percent of the Thomas-Reiche Kuhn (TRK) sum-rule strength. Several calculations predict the appearance of dipole strength at low excitation energies in neutron-rich nuclei. This low-lying strength is often referred to as pygmy dipole resonance (PDR) and, in a macroscopic picture, is discussed in terms of a collective oscillation of excess neutrons versus the core nucleons. Moreover, a sharp rise is observed at the neutron separation threshold around 5 MeV for the odd isotopes. A possible contribution of 'threshold strength', which can be described within the direct-breakup model is discussed. The results for the neutron-rich Sn isotopes are confronted with results on stable nuclei investigated in experiments using real photons.

Published
2007

2. Measurement of the92,93,94,100Mo(γ,n) reactions by Coulomb Dissociation

Author

W. Waluś, Andreas Wagner, Nils Paar, L. Schnorrenberger, S. Walter, R. Kulessa, P. Maierbeck, Nicolas Winckler, W. Prokopowicz, A. Chatillon, R. Palit, G. Surówka, G. Ickert, L. Deveaux, Christoph Langer, C. Nociforo, M. Babilon, S. Müller, Thomas Aumann, Enrique Casarejos, Helmut Weick, Rene Reifarth, S. Altstadt, Håkan T Johansson, Andreas Zilges, H. Alvarez-Pol, K. Lindenberg, A. Movsesyan, M. Hellstroem, M. Elvers, M. Böhmer, Yuri A. Litvinov, T. Le Bleis, K. Sümmerer, F. Käppeler, Ershova, Hans Geissel, F. Aksouh, M. Winkler, A. Brünle, Roland Beyer, Th. W. Elze, B. Fernandez-Dominguez, Dario Vretenar, U. Datta Pramanik, K. Boretzky, P. Adrich, Stefanos Paschalis, Ralf Plag, J. Benlliure, D. M. Rossi, Matthias Heil, D. Cortina-Gil, K.-H. Behr, A. Klimkiewicz, J. V. Kratz, Tanja Heftrich, M. Labiche, Kathrin Göbel, H. Emling, Arnd R. Junghans, M. Erhard, Kerstin Sonnabend, T. Berg, O.A. Kiselev, Thomas Nilsson, Marielle Chartier, F. Wamers, Mario Weigand, Roy Crawford Lemmon, N. Kurz, M. Górska, and Herbert A. Simon

Subjects
Physics, History, Photon, 010504 meteorology & atmospheric sciences, Isotope, Stable isotope ratio, chemistry.chemical_element, 01 natural sciences, Dissociation (chemistry), Computer Science Applications, Education, Nuclear physics, chemistry, Nucleosynthesis, Molybdenum, 0103 physical sciences, Coulomb, ddc:530, Atomic physics, 010303 astronomy & astrophysics, Production chain, 0105 earth and related environmental sciences
Abstract

6th Nuclear Physics in Astrophysics Conference (NPA), Lisbon, Portugal, 19 May 2013 - 24 May 2013; Journal of physics / Conference Series 665, 012034 (2016). doi:10.1088/1742-6596/665/1/012034, Published by IOP Publ., Bristol

Published
2016

3. N/Z Dependence of Projectile Fragmentation

Author

W. G. Lynch, H. Orth, H. Simon, I. Iori, E. Le Gentil, J. Lukasik, Giuseppe Verde, G. Imme, Håkan T Johansson, C. Volant, H. Emling, A. Wieloch, Cornelius Schwarz, C. Boiano, K. Suemmerer, Y. Leifels, H. Sann, A. Chbihi, H. Weick, T. Barczyk, A. Mykulyak, C. Sfienti, M. S. Wallace, S. Bianchin, J.-E. Ducret, E. Rapisarda, J.D. Frankland, C.O. Bacri, J. Brzychczyk, A. Lafriakh, Alberto Pullia, Piotr Pawłowski, P. Adrich, J. Cibor, M. Hellstroem, B. Zwieglinski, R. Bassini, A. Le Fèvre, M. B. Tsang, Thomas Aumann, R. Palit, U. Lynen, G. Raciti, Z. Majka, B. Czech, W. F. Mueller, W. Trautmann, M. Mocko, D. Henzlova, A. Boudard, J. Wiechula, A.N. Otte, M. De Napoli, J. Luehning, K. Kezzar, A. S. Botvina, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), 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), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), ALADIN, 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
Physics, Nuclear and High Energy Physics, Range (particle radiation), Spectrometer, Isotope, 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, FOS: Physical sciences, Limiting, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Neutron detection, Atomic number, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Projectile fragmentation, Beam (structure)
Abstract

The N/Z dependence of projectile fragmentation at relativistic energies has been studied in a recent experiment at the GSI laboratory with the ALADiN forward spectrometer coupled to the LAND neutron detector. Besides a primary beam of 124Sn, also secondary beams of 124La and 107Sn delivered by the FRS fragment separator have been used in order to extend the range of isotopic compositions of the produced spectator sources. With the achieved mass resolution of \Delta A/A \approx 1.5%, lighter isotopes with atomic numbers Z \le 10 are individually resolved. The presently ongoing analyses of the measured isotope yields focus on isoscaling and its relation to the properties of hot fragments at freeze-out and on the derivation of chemical freeze-out temperatures which are found to be independent of the isotopic composition of the studied systems. The latter result is at variance with the predictions for limiting temperatures as obtained with finite-temperature Hartree-Fock calculations., Comment: 11 pages, 5 figures, Proceedings of International Workshop on Nuclear Dynamics in Heavy-Ion Reactions and Neutron Stars, Beijing, July 10-14, 2007, to appear in International Journal of Modern Physics E

Published
2007
Full Text
View/download PDF

4. Longitudinal momentum distributions of {16,18}C fragments after one-neutron removal from {17,19}C

Author

W. Schwab, Takatoshi Suzuki, Thomas Baumann, Hermann Wollnik, M. V. Ivanov, U. C. Bergmann, M. Winkler, Hans Geissel, C. Scheidenberger, Naohito Iwasa, A. Ozawa, F. Nickel, Achim Richter, Mikhail V. Zhukov, Karin Markenroth, Björn Jonson, M. Hellstroem, L. M. Fraile, R. Janik, G. Muenzenberg, H. Lenske, M. H. Smedberg, M. J. G. Borge, G. Schrieder, D. Cortina-Gil, Leif Axelsson, K. Riisager, Thomas Nilsson, Thomas Aumann, K. Suemmerer, Peter Strmen, Herbert A. Simon, and Branislav Sitar

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, Projectile, Nuclear Theory, Theoretical models, FOS: Physical sciences, chemistry.chemical_element, Nuclear physics, Momentum, Full width at half maximum, chemistry, Physics::Accelerator Physics, Neutron, Nuclear Experiment (nucl-ex), Nuclear Experiment, Carbon, Nuclear Physics
Abstract

The fragment separator FRS at GSI was used as an energy-loss spectrometer to measure the longitudinal momentum distributions of {16,18}C fragments after one-neutron removal reactions in {17,19}C impinging on a carbon target at about 910 MeV/u. The distributions in the projectile frames are characterized by a FWHM of 141+-6 MeV/c for {16}C and 69+-3 MeV/c for {18}C. The results are compared with experimental data obtained at lower energies and discussed within existing theoretical models., 10 pages, 5 figures; uses elsart style; corrected list of authors; will be published in Phys. Lett. B

Published
1998

Catalog

Books, media, physical & digital resources
See catalog results