The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.

Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N-20,N-21 are reported. Relativistic N-20,N-21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N-19(n,gamma)N-20 and N-20(n,gamma)N-21 excitation functions and thermonuclear reaction rates have been determined. The N-19(n,gamma)N-20 rate is up to a factor of 5 higher at T < 1 GK with respect to previous theoretical calculations, leading to a 10% decrease in the predicted fluorine abundance.

Isobaric charge-exchange reactions induced by different tin isotopes have been investigated at GSI. The high-resolving power of the FRS spectrometer made it possible to separate elastic and inelastic components in the missing-energy spectra of the ejectiles. The inelastic component was associated to the in-medium excitation of nucleon resonances such as the Delta and Roper resonances. These data are expected to contribute to better understand the in-medium properties of baryon resonances but also to investigate the abundance of protons and neutrons at the nuclear periphery.

The time-reversed reaction O-15(2p, gamma) Ne-17 has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of Ne-20 in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-(RB)-B-3 experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (sigma(Coul)) have been calculated, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the nuclear structure of the Ne-17 nucleus will be obtained. The analysis is in progress.

J Marganiec1,5, F Wamers1,2,3,25, F Aksouh3,23, Y Aksyutina3, H Alvarez Pol6, T Aumann2,3, S Beceiro6, C Bertulani7, K Boretzky3, M J Borge8, M Chartier9, A Chatillon3, L Chulkov3, D Cortina-Gil6, I Egorova15, H Emling3, O Ershova3,4, C Forssén11, L M Fraile12,13, H Fynbo14, D Galaviz8, H Geissel3, L Grigorenko15,27, M Heil3, D H H Ho↵mann2, J Ho↵mann3, H Johansson11, B Jonson11,M Karakoç24, C Karagiannis3, O Kiselev3, J V Kratz16, R Kulessa17, N Kurz3, C Langer3,4, M Lantz11,18, K Larsson3, T Le Bleis3,19, R Lemmon9, Yu A Litvinov3, K Mahata3,20, C Müntz4, T Nilsson11, C Nociforo3, G Nyman11, W Ott3, V Panin2,3,Yu Parfenova15,28, S Paschalis2,9, A Perea8, R Plag3,4, R Reifarth3,4, A Richter2,K Riisager14, C Rodŕıguez Tajes6,22, D Rossi3,16,29, G Schrieder2, N Shulgina11,21, H Simon3, J Stroth4, K Sümmerer3, J Taylor9, O Tengblad8, E Tengborn11, H Weick3, M Wiescher26,5, C Wimmer3,4, M Zhukov11 EMMI, Darmstadt, Germany; TU Darmstadt, Germany; GSI Darmstadt, Germany; Goethe-Universität, Frankfurt am Main, Germany; JINA, Notre Dame, USA; Santiago de Compostela University, Spain; Texas A&M University-Commerce, USA; IEM Madrid, Spain; University of Liverpool, UK; CEA/DAM/DIF Bruyere, France; Chalmers I.T., Sweden; Universidad Complutense de Madrid, Spain; CERN, Geneva, Switzerland; Aarhus University, Denmark; FLNR JINR Dubna, Russia; University of Mainz, Germany; Jagiellonian University, Krakow, Poland; Uppsala University, Uppsala, Sweden; TU München, Germany; BARC Mumbai, India; Kurchatov Institute, Moscow, Russia; GANIL, CEA/DSM-CNRS/IN2P3, France; King Saud University, Kingdom of Saudi Arabia; Akdeniz University, Turkey; FIAS Frankfurt am Main, Germany; University of Notre Dame, USA; RRC KI, Moscow, Russia; INP, Moscow, Russia; NSCL, MSU, East Lansing, USA

Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s)⊗νs1/2 and 29Na(g.s)⊗νs1/2,respectively.

Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s)⊗νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al.

J. Marganiec, F. Wamers, F. Aksouh, Y. Aksyutina H. Alvarez Pol , T. Aumann, S. Beceiro , C. Bertulani, K. Boretzky M.J.G. Borge, M. Chartier, A. Chatillon, L. Chulkov, D. Cortina-Gil I. Egorova, H. Emling, O. Ershova, C. Forssén, L.M. Fraile H. Fynbo, D. Galaviz, H. Geissel, L. Grigorenko, M. Heil D.H.H. Hoffmann, J. Hoffmann, H. Johansson, B. Jonson, M. Karakoç C. Karagiannis, O. Kiselev, J.V. Kratz, R. Kulessa, N. Kurz C. Langer, M. Lantz, K. Larsson, T. Le Bleis, R. Lemmon Yu.A. Litvinov, K. Mahata, C. Müntz, T. Nilsson, C. Nociforo G. Nyman, W. Ott, V. Panin, Yu. Parfenova, S. Paschalis A. Perea, R. Plag, R. Reifarth, A. Richter, K. Riisager C. Rodríguez Tajes, D. Rossi, G. Schrieder, N. Shulgina H. Simon, J. Stroth, K. Sümmerer, J. Taylor, O. Tengblad E. Tengborn, H. Weick, M. Wiescher, C. Wimmer, M. Zhukov

Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.

The O-15(2p, gamma)Ne-17 cross section has been studied by the inverse reaction, the Coulomb dissociation of Ne-17. The experiment has been performed at the GSI. The Ne-17 excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb dissociation cross sections (sigma(Coul)) have been extracted, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the Ne-17 nuclear structure will be obtained. The analysis is in progress.

The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.

The time-reversed reaction 15O(2p, γ)17Ne has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of 20Ne in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-R3B experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (σCoul) have been calculated, which provide a photoabsorption (σphoto) and a radiative capture cross section (σcap). Additionally, important information about the nuclear structure of the 17Ne nucleus will be obtained. The analysis is in progress.

The nucleosynthesis of Fe-60 is one of the current outstanding problems in nuclear astrophysics. Observations of galactic radioactivity by gamma-ray telescopes have provided a direct measurement of the Fe-60/(26) Al ratio dispersed across the galactic plane. As the two isotopes are thought to be produced in similar stellar environments, the ratio provides a unique constraint on current stellar models. Specifically, Fe-60 is expected to be created and destroyed by neutron capture on stable iron isotopes. A recent measurement of the F-60,(n, gamma)F-61, reaction has provided a first experimental quantification of the destruction rate. Currently, no experimental data exist for the Fe-59(n, gamma)F-60, production rate. To address this void, a Coulomb dissociation experiment has been performed at GSI in an attempt to indirectly measure the ground state neutron capture cross section of Fe-59. The Fe-60 beam was produced by fragmentation of a 660 AMeV primary Ni-64 beam by a Be target. The subsequent Fe-60 fragments were separated using the FRS and impinged on a lead target. The experimental setup provides for an event-by-event reconstruction of the four-momenta of all incoming particles and reaction products. The analysis is currently ongoing.

Capture Gamma-Ray Spectroscopy and Related Topics, pp. 347-353 (2013) No AccessFIRST EXPERIMENTAL CONSTRAINT ON THE 59Fe(n, γ)60Fe CROSS SECTION FROM COULOMB DISSOCIATIONE. UBERSEDER, M. WIESCHER, T. HEFTRICH, O. ERSHOVA, C. LANGER, R. PLAG, G. RASTREPINA, R. REIFARTH, K. SONNABEND, M. WEIGAND, C. WIMMER, T. ADACHI, A. NAJAFI, C. RIGOLLET, B. STREICHER, T. AUMANN, C. CAESAR, M. HEINE, M. HOLL, A. MOVSESYAN, V. PANIN, F. WAMERS, S. BECEIRO, K. BORETZKY, A. ESTRADE, M. HEIL, A. IGNATOV, YU. A. LITVINOV, V. RICCIARDI, H. SIMON, V. VOLKOV, H. WEICK, N. WINCKLER, S. CHAKRABORTY, A. RAHAMAN, H. JOHANSSON, T. LEBLEIS, J. MARGANIEC, D. ROSSI, D. SAVRAN, and P. J. WOODSE. UBERSEDERUniversity of Notre Dame, Notre Dame, IN 46545, USA, M. WIESCHERUniversity of Notre Dame, Notre Dame, IN 46545, USA, T. HEFTRICHUniversity of Frankfurt, Germany, O. ERSHOVAUniversity of Frankfurt, Germany, C. LANGERUniversity of Frankfurt, Germany, R. PLAGUniversity of Frankfurt, Germany, G. RASTREPINAUniversity of Frankfurt, Germany, R. REIFARTHUniversity of Frankfurt, Germany, K. SONNABENDUniversity of Frankfurt, Germany, M. WEIGANDUniversity of Frankfurt, Germany, C. WIMMERUniversity of Frankfurt, Germany, T. ADACHIKVI Groningen, Netherlands, A. NAJAFIKVI Groningen, Netherlands, C. RIGOLLETKVI Groningen, Netherlands, B. STREICHERKVI Groningen, Netherlands, T. AUMANNTU Darmstadt, Germany, C. CAESARTU Darmstadt, Germany, M. HEINETU Darmstadt, Germany, M. HOLLTU Darmstadt, Germany, A. MOVSESYANTU Darmstadt, Germany, V. PANINTU Darmstadt, Germany, F. WAMERSTU Darmstadt, Germany, S. BECEIROUniversity of Santiago de Compostela, Spain, K. BORETZKYGSI Darmstadt, Germany, A. ESTRADEGSI Darmstadt, Germany, M. HEILGSI Darmstadt, Germany, A. IGNATOVGSI Darmstadt, Germany, YU. A. LITVINOVGSI Darmstadt, Germany, V. RICCIARDIGSI Darmstadt, Germany, H. SIMONGSI Darmstadt, Germany, V. VOLKOVGSI Darmstadt, Germany, H. WEICKGSI Darmstadt, Germany, N. WINCKLERGSI Darmstadt, Germany, S. CHAKRABORTYSINP Kolkata, India, A. RAHAMANSINP Kolkata, India, H. JOHANSSONChalmers University of Technology, Sweden, T. LEBLEISTU Munich, Germany, J. MARGANIECExtreMe Matter Institute EMMI, GSI, D. ROSSIJohannes Gutenberg University of Mainz, Germany, D. SAVRANFrankfurt Institute for Advanced Studies, Germany, and P. J. WOODSUniversity of Edinburgh, United Kingdomhttps://doi.org/10.1142/9789814383646_0046Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The nucleosynthesis of 60Fe is one of the current outstanding problems in nuclear astrophysics. Observations of galactic radioactivity by γ-ray telescopes have provided a direct measurement of the 60Fe/26 Al ratio dispersed across the galactic plane. As the two isotopes are thought to be produced in similar stellar environments, the ratio provides a unique constraint on current stellar models. Specifically, 60Fe is expected to be created and destroyed by neutron capture on stable iron isotopes. A recent measurement of the 60Fe(n, γ)61Fe reaction has provided a first experimental quantification of the destruction rate. Currently, no experimental data exist for the 59Fe(n, γ)60Fe production rate. To address this void, a Coulomb dissociation experiment has been performed at GSI in an attempt to indirectly measure the ground state neutron capture cross section of 59Fe. The 60Fe beam was produced by fragmentation of a 660 AMeV primary 64Ni beam by a Be target. The subsequent 60Fe fragments were separated using the FRS and impinged on a lead target. The experimental setup provides for an event-by-event reconstruction of the four-momenta of all incoming particles and reaction products. The analysis is currently ongoing. FiguresReferencesRelatedDetails Recommended Capture Gamma-Ray Spectroscopy and Related TopicsMetrics History PDF download

A Coulomb dissociation experiment on the proton-rich 32Ar and 34Ar isotopes was performed at the ALADIN-LAND setup at GSI in Darmstadt. Recent RQRPA calculations show a low-lying E1 soft-vibrational mode at an excitation energy Ex ≈ 9 MeV for proton-rich argon isotopes at the dripline. In a macroscopic picture, this can be understood as an out-of-phase oscillation of a thin proton skin against the isospin-saturated core, similar to the neutron pygmy resonance at the neutron dripline. On the other hand, the measured (γ, p) reactions are interesting for the calculation of reaction cross-sections and radiative proton capture rates for the rp-process. In this hydrogen burning process a lot of nuclear structure inputs are still missing. Especially in the argon region a bottleneck for the reaction flow is assumed at 30S and 34Ar. The impact of the predicted proton pygmy resonance on the reaction flow is not yet clear. The experimental motivation and the experiment itself are described. Identification plots for incoming and outgoing particles are shown and a tracking algorithm is applied and shows to work succesfully. © Copyright owned by the author(s).

The Al-26 nucleus has a shorter life-time than the Universe showing that the nucleosynthesis of this element might be an ongoing process in stars. The reaction Si-26(p,gamma)P-27 competes with the production of Al-26. Coulomb dissociation of P-27 is an indirect method to measure that reaction. An experiment was performed at GSI with a Ar-36 primary beam at 500 MeV to measure this reaction.

Experiments were performed in Cave C of GSI (Gesellschaft für Schwerionenforschung) using the LAND (Large Area Neutron Detector) in combination with the deflection magnet ALADIN (A LArge DIpol magNet) in front of the LAND where charged particles and neutrons can be separated. This arrangement is used to create high-energetic neutron fields by irradiation of a thick lead target (5 cm) with deuteron beams with the energies of 500 or 800 MeV per nucleon. In break-up reactions the neutron is separated from the proton which is deflected in the magnetic field of the ALADIN. The produced neutron radiation, which has a pronounced peak at the nucleon energy, is used to measure the fluence response of the GSI neutron ball. A thermoluminescence (TL) based spherical neutron dosemeter was developed for the area monitoring for the quantity H(10) at high-energy accelerators. In the same experiment, the spectral neutron fluence Phi(E) is measured with the LAND in the energy range from 100 MeV to 1 GeV. The measured fluence responses are compared with results of FLUKA calculations and the corresponding fluence-to-dose conversion coefficients. The measured dosemeter responses are too high in comparison to the calculated ones (up to approximately 50%), the dosemeter reading gives dose values which are too high by a factor of 1.1-2.2 related to the corresponding fluence-to-dose conversion factors.

A neutron field is produced by bombarding a lead brick with 500 and 800 AMeV deuterons.The incoming deuterons break up into protons and neutrons mainly due to Coulomb interaction with the high-Z target nuclei.The resulting charged products are deflected by a strong dipole magnet behind the target.The spectrum of the remaining neutrons in forward direction is measured from 0.1 MeV to 1.5 GeV with the time-of-flight method.Two neutron dosimeters are tested in the neutron field described above: The extended-range rem-counter WENDI-2 from Thermo-Electron® Corporation reveals a fluence response of 778 pSv cm 2 and 947 pSv cm 2 for neutrons of energy 482 MeV and 789 MeV, respectively.A thermo-luminescence based extended range neutron dosimeter developed at GSI exhibits a fluence response of 623 pSv cm 2 and 634 pSv cm 2 , respectively.A conventional version of the passive neutron dosimeter yields dose values which are lower by a factor of 5 demonstrating the advantage of the extended-range neutron dose equivalent meters.