WorldWideScience

Sample records for rich nuclei produced

  1. Neutron rich nuclei

    International Nuclear Information System (INIS)

    Foucher, R.

    1979-01-01

    If some β - emitters are particularly interesting to study in light, medium, and heavy nuclei, another (and also) difficult problem is to know systematically the properties of these neutron rich nuclei far from the stability line. A review of some of their characteristics is presented. How far is it possible to be objective in the interpretation of data is questioned and implications are discussed

  2. Study of very neutron-rich nuclei produced by means of a 48Ca beam

    International Nuclear Information System (INIS)

    Lewitowicz, M.; Artukh, A.G.

    1991-01-01

    The results of experiments with a 48 Ca beam performed at GANIL are presented and discussed. More than 30 very neutron-rich isotopes were identified or studied for the first time. The evidence for particle-unstable character of the 26 O isotope is reported. Half-life measurements for light neutron rich nuclei are compared with different theoretical predictions. (author) 14 refs.; 6 figs.; 1 tab

  3. Identification of new neutron-rich rare-earth nuclei produced in /sup 252/Cf spontaneous fission

    CERN Document Server

    Greenwood, R C; Gehrke, R J; Meikrantz, D H

    1981-01-01

    A program of systematic study of the decay properties of neutron-rich rare-earth nuclei with 30 sproduced in /sup 252/Cf spontaneous fission, is currently underway using the Idaho ESOL (Elemental Separation On Line) Facility. The chemistry system used for the rare-earth elemental separations consists of two high-performance chromatography columns connected in series and coupled to the /sup 252 /Cf fission source via a helium gas-jet transport arrangement. The time delay for separation and initiation of gamma -ray counting with results which have been obtained to date with this system include the identification of a number of new neutron-rich rare-earth isotopes including /sup 155/Pm (t/sub 1/2/=48+or-4 s) and /sup 163/Gd (t/sub 1 /2/=68+or-3 s), in addition to 5.51 min /sup 158/Sm which was identified in an earlier series of experiments. (11 refs).

  4. Neutron rich nuclei around 132Sn

    International Nuclear Information System (INIS)

    Bhattacharya, Sarmishtha

    2016-01-01

    The neutron rich nuclei with few particles or holes in 132 Sn have various experimental and theoretical interest to understand the evolution of nuclear structure around the doubly magic shell closure Z=50 and N=82. Some of the exotic neutron rich nuclei in this mass region are situated near waiting points in the r-process path and are of special astrophysical interest. Neutron rich nuclei near 132 Sn have been studied using fission fragment spectroscopy. The lifetime of low lying isomeric states have been precisely measured and the beta decay from the ground and isomeric states have been characterized using gamma-ray spectroscopy

  5. Structure of Light Neutron-rich Nuclei

    International Nuclear Information System (INIS)

    Dlouhy, Zdenek

    2007-01-01

    In this contribution we searched for irregularities in various separation energies in the frame of mass measurement of neutron-rich nuclei at GANIL. On this basis we can summarize that the new doubly magic nuclei are 8 He, 22 O and 24 O. They are characterized by extra stability and, except 24 O, they cannot accept and bind additional neutrons. However, if we add to these nuclei a proton we obtain 9 Li and 25 F which are the core for two-neutron halo nucleus 11 Li and enables that fluorine can bound even 6 more neutrons, respectively. In that aspect the doubly magic nuclei in the neutron-rich region can form the basis either for neutron halo or very neutron-rich nuclei. (Author)

  6. Proton radioactivity from proton-rich nuclei

    International Nuclear Information System (INIS)

    Guzman, F.; Goncalves, M.; Tavares, O.A.P.; Duarte, S.B.; Garcia, F.; Rodriguez, O.

    1999-03-01

    Half-lives for proton emission from proton-rich nuclei have been calculated by using the effective liquid drop model of heavy-particle decay of nuclei. It is shown that this model is able to offer results or spontaneous proton-emission half-life-values in excellent agreement with the existing experimental data. Predictions of half-life-values for other possible proton-emission cases are present for null orbital angular momentum. (author)

  7. Calculation of the radii of neutron rich light exotic nuclei

    International Nuclear Information System (INIS)

    Charagi, S.K.; Gupta, S.K.

    1991-01-01

    The interaction cross section of a few unstable neutron rich nuclei have been measured using exotic isotope beams produced through the projectile fragmentation process in high energy heavy-ion collisions. Interaction cross section of He, Li, Be and B isotope projectiles with Be, C and Al targets have thus been measured at 790 MeV/nucleon. We have made a comprehensive analysis of the data on the interaction cross section, to extract the radii of these neutron rich light nuclei. 7 refs., 1 fig., 3 tabs

  8. Structure of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Nazarewicz, W.; Oak Ridge National Lab., TN; Warsaw Univ.

    1997-11-01

    One of the frontiers of today's nuclear science is the ''journey to the limits'': of atomic charge and nuclear mass, of neutron-to-proton ratio, and of angular momentum. The new data on exotic nuclei are expected to bring qualitatively new information about the fundamental properties of the nucleonic many-body system, the nature of the nuclear interaction, and nucleonic correlations at various energy-distance scales. In this talk, current developments in nuclear structure of neutron-rich nuclei are discussed from a theoretical perspective

  9. Structure of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Nazarewicz, W.

    2000-01-01

    Complete text of publication follows. The uncharted regions of the (N,Z) plane contain information that can answer many questions of fundamental importance for science: How many protons and neutrons can be clustered together by the strong interaction to form a bound nucleus? What are the proton and neutron magic numbers of the exotic nuclei? What are the properties of very short-lived exotic nuclei with extreme neutron-to-proton ratios? What is the effective nucleon-nucleon interaction in a nucleus that has a very large neutron excess? Nuclear life far from stability is different from that around the stability line; the promised access to completely new combinations of proton and neutron numbers offers prospects for new structural phenomena. The main objective of this talk is to discuss some of the challenges and opportunities of research with exotic nuclei. The covered topics will include: Theoretical challenges; Skins and halos in heavy nuclei; Shape coexistence in exotic nuclei; Beta-decays of neutron-rich nuclei. (author)

  10. Modeling a neutron rich nuclei source

    Energy Technology Data Exchange (ETDEWEB)

    Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J. [Institut de Physique Nucleaire, IN2P3/CNRS, 91 - Orsay (France); Mirea, M. [Institute of Physics and Nuclear Engineering, Tandem Lab., Bucharest (Romania)

    2000-07-01

    The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (author000.

  11. Modeling a neutron rich nuclei source

    International Nuclear Information System (INIS)

    Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J.; Mirea, M.

    2000-01-01

    The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (authors)

  12. Reactions with fast radioactive beams of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like {sup 11}Li and {sup 12}Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  13. Reactions with fast radioactive beams of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Aumann, T.

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like 11 Li and 12 Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  14. Relativistic mean field calculations in neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, G.; Bhattacharya, Madhubrata [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Roy, Subinit [Saha Institute of Nuclear Physics, Block AF, Sector 1, Kolkata- 700 064 (India)

    2014-08-14

    Relativistic mean field calculations have been employed to study neutron rich nuclei. The Lagrange's equations have been solved in the co-ordinate space. The effect of the continuum has been effectively taken into account through the method of resonant continuum. It is found that BCS approximation performs as well as a more involved Relativistic Continuum Hartree Bogoliubov approach. Calculations reveal the possibility of modification of magic numbers in neutron rich nuclei. Calculation for low energy proton scattering cross sections shows that the present approach reproduces the density in very light neutron rich nuclei.

  15. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

    Science.gov (United States)

    Stefan, I.; Fornal, B.; Leoni, S.; Azaiez, F.; Portail, C.; Thomas, J. C.; Karpov, A. V.; Ackermann, D.; Bednarczyk, P.; Blumenfeld, Y.; Calinescu, S.; Chbihi, A.; Ciemala, M.; Cieplicka-Oryńczak, N.; Crespi, F. C. L.; Franchoo, S.; Hammache, F.; Iskra, Ł. W.; Jacquot, B.; Janssens, R. V. F.; Kamalou, O.; Lauritsen, T.; Lewitowicz, M.; Olivier, L.; Lukyanov, S. M.; Maccormick, M.; Maj, A.; Marini, P.; Matea, I.; Naumenko, M. A.; de Oliveira Santos, F.; Petrone, C.; Penionzhkevich, Yu. E.; Rotaru, F.; Savajols, H.; Sorlin, O.; Stanoiu, M.; Szpak, B.; Tarasov, O. B.; Verney, D.

    2018-04-01

    Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example.

  16. Structure of proton-rich nuclei of astrophysical interest

    Energy Technology Data Exchange (ETDEWEB)

    Roeckl, E [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany)

    1998-06-01

    Recent experimental data concerning proton-rich nuclei between A=20 and A=100 are presented and discussed with respect to their relevance to the astrophysical rp process and to the calibration of solar neutrino detectors. (orig.)

  17. Maris polarization in neutron-rich nuclei

    Science.gov (United States)

    Shubhchintak; Bertulani, C. A.; Aumann, T.

    2018-03-01

    We present a theoretical study of the Maris polarization effect and its application in quasi-free reactions to assess information on the structure of exotic nuclei. In particular, we explore the dependence of the polarization effect on neutron excess and neutron-skin thickness. We discuss the uncertainties in the calculations of triple differential cross sections and of analyzing powers due the choices of various nucleon-nucleon interactions and optical potentials and the limitations of the method. Our study implies that polarization variables in (p, 2p) reactions in inverse kinematics can be an effective probe of single-particle structure of nuclei in radioactive-beam facilities.

  18. Two-proton knockout on neutron-rich nuclei

    International Nuclear Information System (INIS)

    Bazin, D.; Brown, B.A.; Campbell, C.M.; Church, J.A.; Dinca, D.C.; Enders, J.; Gade, A.; Glasmacher, T.; Hansen, P.G.; Mueller, W.F.; Olliver, H.; Perry, B.C.; Sherrill, B.M.; Terry, J.R.; Tostevin, J.A.

    2004-01-01

    Two-proton knockout reactions on neutron-rich nuclei [Phys. Rev. Lett. 91 (2003) 012501] have been studied in inverse kinematics at intermediate energy. Strong evidence that the two-proton removal from a neutron-rich system proceeds as a direct reaction is presented, together with a preliminary theoretical discussion of the partial cross sections based on eikonal reaction theory and the many-body shell model. They show that this reaction can be used to characterize the wave functions of the projectiles and holds great promise for the study of neutron-rich nuclei

  19. Maris polarization in neutron-rich nuclei

    Directory of Open Access Journals (Sweden)

    Shubhchintak

    2018-03-01

    Full Text Available We present a theoretical study of the Maris polarization effect and its application in quasi-free reactions to assess information on the structure of exotic nuclei. In particular, we explore the dependence of the polarization effect on neutron excess and neutron-skin thickness. We discuss the uncertainties in the calculations of triple differential cross sections and of analyzing powers due the choices of various nucleon–nucleon interactions and optical potentials and the limitations of the method. Our study implies that polarization variables in (p, 2p reactions in inverse kinematics can be an effective probe of single-particle structure of nuclei in radioactive-beam facilities.

  20. Nucleosynthesis of neutron-rich heavy nuclei during explosive helium burning in massive stars

    International Nuclear Information System (INIS)

    Blake, J.B.; Woosley, S.E.; Weaver, T.A.; Schramm, D.N.

    1981-01-01

    The production of heavy nuclei during explosive helium burning has been calculated using a hydrodynamical model of a 15 M/sub sun/ (Type II) supernovae and a n-process nuclear reaction network. The resulting neutron-rich heavy nuclei are not produced in the relative abundances of solar-system r-process material, especially in the vicinity of Pt, nor are any actinides produced. These deficiencies reflect an inadequate supply of neutrons. However, some neutron-rich isotopes, normally associated with the r-process, are produced which may be significant for the production of isotopic anomalies in meteorites

  1. Trends in the study of light proton rich nuclei

    International Nuclear Information System (INIS)

    Moltz, D.M.; Aysto, J.; Hotchkis, M.A.C.; Cerny, J.

    1985-09-01

    Recent work in light proton-rich nuclei is reviewed. Evidence for the first T/sub z/ = -5/2 nuclide, 35 Ca, is presented. The mechanisms of two-proton emission following beta-decay is investigated. Future directions in this field are discussed. 23 refs., 5 figs

  2. Haloes and clustering in light, neutron-rich nuclei

    International Nuclear Information System (INIS)

    Orr, N.A.

    2001-10-01

    Clustering is a relatively widespread phenomenon which takes on many guises across the nuclear landscape. Selected topics concerning the study of halo systems and clustering in light, neutron-rich nuclei are discussed here through illustrative examples taken from the Be isotopic chain. (author)

  3. Isospin Conservation in Neutron Rich Systems of Heavy Nuclei

    Science.gov (United States)

    Jain, Ashok Kumar; Garg, Swati

    2018-05-01

    It is generally believed that isospin would diminish in its importance as we go towards heavy mass region due to isospin mixing caused by the growing Coulomb forces. However, it was realized quite early that isospin could become an important and useful quantum number for all nuclei including heavy nuclei due to neutron richness of the systems [1]. Lane and Soper [2] also showed in a theoretical calculation that isospin indeed remains quite good in heavy mass neutron rich systems. In this paper, we present isospin based calculations [3, 4] for the fission fragment distributions obtained from heavy-ion fusion fission reactions. We discuss in detail the procedure adopted to assign the isospin values and the role of neutron multiplicity data in obtaining the total fission fragment distributions. We show that the observed fragment distributions can be reproduced rather reasonably well by the calculations based on the idea of conservation of isospin. This is a direct experimental evidence of the validity of isospin in heavy nuclei, which arises largely due to the neutron-rich nature of heavy nuclei and their fragments. This result may eventually become useful for the theories of nuclear fission and also in other practical applications.

  4. Beta decay rates of neutron-rich nuclei

    Science.gov (United States)

    Marketin, Tomislav; Huther, Lutz; Petković, Jelena; Paar, Nils; Martínez-Pinedo, Gabriel

    2016-06-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  5. Beta decay rates of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Marketin, Tomislav; Petković, Jelena; Paar, Nils; Huther, Lutz; Martínez-Pinedo, Gabriel

    2016-01-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  6. Beta decay rates of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Marketin, Tomislav, E-mail: marketin@phy.hr; Petković, Jelena; Paar, Nils [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)

    2016-06-21

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei. Aside from the astrophysical applications, the results of this calculation can also be employed in the modeling of the electron and antineutrino spectra from nuclear reactors.

  7. Beta decay rates of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Marketin, Tomislav; Huther, Lutz; Martínez-Pinedo, Gabriel

    2015-01-01

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei

  8. Beta decay rates of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Marketin, Tomislav, E-mail: marketin@phy.hr [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Huther, Lutz [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); Martínez-Pinedo, Gabriel [Institut für Kernphysik (Theoriezentrum), Technische Universität Darmstadt, 64289 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerioneneforschung, Planckstraße 1, 64291 Darmstadt (Germany)

    2015-10-15

    Heavy element nucleosynthesis models involve various properties of thousands of nuclei in order to simulate the intricate details of the process. By necessity, as most of these nuclei cannot be studied in a controlled environment, these models must rely on the nuclear structure models for input. Of all the properties, the beta-decay half-lives are one of the most important ones due to their direct impact on the resulting abundance distributions. Currently, a single large-scale calculation is available based on a QRPA calculation with a schematic interaction on top of the Finite Range Droplet Model. In this study we present the results of a large-scale calculation based on the relativistic nuclear energy density functional, where both the allowed and the first-forbidden transitions are studied in more than 5000 neutron-rich nuclei.

  9. Shell gap reduction in neutron-rich N=17 nuclei

    International Nuclear Information System (INIS)

    Obertelli, A.; Gillibert, A.; Alamanos, N.; Alvarez, M.; Auger, F.; Dayras, R.; Drouart, A.; France, G. de; Jurado, B.; Keeley, N.; Lapoux, V.; Mittig, W.; Mougeot, X.; Nalpas, L.; Pakou, A.; Patronis, N.; Pollacco, E.C.; Rejmund, F.; Rejmund, M.; Roussel-Chomaz, P.; Savajols, H.; Skaza, F.; Theisen, Ch.

    2006-01-01

    The spectroscopy of 27 Ne has been investigated through the one-neutron transfer reaction 26 Ne(d,p) 27 Ne in inverse kinematics at 9.7 MeV/nucleon. The results strongly support the existence of a low-lying negative parity state in 27 Ne, which is a signature of a reduced sd-fp shell gap in the N=16 neutron-rich region, at variance with stable nuclei

  10. Very proton-rich nuclei with N asymptotically equals 82

    International Nuclear Information System (INIS)

    Nolte, E.

    1984-01-01

    The proton-rich nuclei with N asymptotically equals 82 show beautifully properties, which are perfectly described by the nuclear shell model. Some of these properties are the occurrence of seniority isomerism in the proton-rich N=82 isotones and the perfect description of the corresponding life times by the seniority scheme as well as the observation of favoured Gamow-Teller β transitions in this nuclear region and the dependence of the corresponding ft values on the number of the envolved nucleons. (author)

  11. GALS – setup for production and study of heavy neutron rich nuclei

    Directory of Open Access Journals (Sweden)

    Zemlyanoy Sergey

    2015-01-01

    Full Text Available The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N = 126 below 208Pb is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion–fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of 136Xe with 208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N=126.

  12. GALS – setup for production and study of heavy neutron rich nuclei

    CERN Document Server

    Zemlyanoy, Sergey; Kozulin, Eduard; Kudryavtsev, Yury; Fedosseev, Valentin; Bark, Robert; Janas, Zenon; Othman, Hosam

    2015-01-01

    The present limits of the upper part of the nuclear map are very close to stability while the unexplored area of heavy neutron-rich nuclides along the neutron closed shell N = 126 below ^208Pb is extremely important for nuclear astrophysics investigations and, in particular, for the understanding of the r-process of astrophysical nucleosynthesis. This area of the nuclear map can be reached neither in fusion-fission reactions nor in fragmentation processes widely used nowadays for the production of exotic nuclei. A new way was recently proposed for the production of these nuclei via low-energy multi-nucleon transfer reactions. The estimated yields of neutron-rich nuclei are found to be significantly high in such reactions and several tens of new nuclides can be produced, for example, in the near-barrier collision of ^136Xe with ^208Pb. A new setup is proposed to produce and study heavy neutron-rich nuclei located along the neutron closed shell N=126.

  13. Properties of neutron-rich nuclei studied by fission product nuclear chemistry

    International Nuclear Information System (INIS)

    Meyer, R.A.; Henry, E.A.; Griffin, H.C.; Lien, O.G. III; Lane, S.M.; Stevenson, P.C.; Yaffe, R.P.; Skarnemark, G.

    1979-09-01

    A review is given of the properties of neutron-rich nuclei studied by fission product nuclear chemistry and includes the techniques used in elemental isolation and current research on the structure of nuclei near 132 Sn, particle emission, and coexisting structure in both neutron-poor and neutron-rich nuclei. 35 references

  14. The pygmy dipole resonance in neutron-rich nuclei

    International Nuclear Information System (INIS)

    Hung, Nguyen Quang; Kiet, Hoang Anh Tuan; Duc, Huynh Ngoc; Chuong, Nguyen Thi

    2016-01-01

    The pygmy dipole resonance (PDR), which has been observed via the enhancement of the electric dipole strength E 1 of atomic nuclei, is studied within a microscopic collective model. The latter employs the Hartree-Fock (HF) method with effective nucleon-nucleon interactions of the Skyrme types plus the random-phase approximation (RPA). The results of the calculations obtained for various even-even nuclei such as "1"6"-"2"8O, "4"0"-"5"8Ca, "1"0"0"-"1"2"0Sn, and "1"8"2"-"2"1"8Pb show that the PDR is significantly enhanced when the number of neutrons outside the stable core of the nucleus is increased, that is, in the neutron-rich nuclei. As the result, the relative ratio between the energy weighted sum of the strength of the PDR and that of the GDR (giant dipole resonance) does not exceed 4%. The collectivity of the PDR and GDR states will be also discussed. (paper)

  15. Nuclear transition moment measurements of neutron rich nuclei

    Science.gov (United States)

    Starosta, Krzysztof

    2009-10-01

    The Recoil Distance Method (RDM) and related Doppler Shift Attenuation Method (DSAM) are well-established tools for lifetime measurements following nuclear reactions near the Coulomb barrier. Recently, the RDM was implemented at National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University using NSCL/K"oln plunger device and a unique combination of the state-of-the-art instruments available there. Doppler-shift lifetime measurements following Coulomb excitation, knock-out, and fragmentation at intermediate energies of ˜100 MeV/u hold the promise of providing lifetime information for excited states in a wide range of unstable nuclei. So far, the method was used to investigate the collectivity of the neutron-rich ^16,18,20C, ^62,64,66Fe, ^70,72Ni, ^110,114Pd isotopes and also of the neutron-deficient N=Z ^64Ge. A significant fraction of these experiments was performed using NSCL's Segmented Germanium Array instrumented with the Digital Data Acquisition System which enables gamma-ray tracking. The impact of GRETINA and gamma-ray tracking on RDM and DSAM studies of neutron-rich nuclei will be discussed.

  16. Lifetime measurement in neutron-rich A ∝ 100 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, Saba; Jolie, Jan; Regis, Jean-Marc; Saed-Samii, Nima; Warr, Nigel [Institute for Nuclear Physics, University of Cologne, Cologne (Germany); Collaboration: EXILL-FATIMA-Collaboration

    2016-07-01

    Rapid shape changes are observed in the region of neutron rich nuclei with a mass around A=100. Precise lifetime measurements are a key ingredient in the systematic study of the evolution of nuclear deformation and the degree of collectivity in this region. Nuclear lifetimes of excited states can be obtained using the fast-timing technique with LaBr{sub 3}(Ce)-scintillators. We used neutron induced fission of {sup 241}Pu in order to study lifetimes of excited states of fission fragments in the A∝100 region. The EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin comprises of 8 BGO-shielded EXOGAM clover detectors and 16 very fast LaBr{sub 3}(Ce)-scintillator detectors, which were installed around the fission target. We have studied the lifetimes of low lying states for the nuclei {sup 98}Zr, {sup 100}Zr and {sup 102}Zr by applying the generalized centroid difference method. In this contribution we report on the used fast-timing setup and present preliminary results for the studied isotopes.

  17. Delayed protons and properties of proton-rich nuclei

    International Nuclear Information System (INIS)

    Karnaukhov, V.A.

    1976-01-01

    The object of the investigation is to study the properties of proton-rich nuclei. The emphasis in the proposed survey is made on investigations in the range of Z > 50. Measurement of the total energy in emission of delayed protons (DP) enables one to determine the difference between the masses of initial and final isotopes. The statistical model of the DP emission is used for describing the proton spectrum. A comparison of the DP experimental and theoretical spectra shows that the presence of local resonances in the strength functions of the β dacay is rather a rule than an exception. Studies into the fine structure of the proton spectra supply information of the density of nuclei considerably removed from the β-stability line at the excitation energies of 3-7 MeV. The aproaches for retrieval of nuclear information with the aid of proton radiators developed so far can serve as a good basis for systematic investigation over a wide range of A and Z

  18. Production of proton-rich nuclei around Z = 84-90 in fusion-evaporation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Peng-Hui [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); University of Chinese Academy of Sciences, Beijing (China); Feng, Zhao-Qing; Li, Jun-Qing; Jin, Gen-Ming [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Niu, Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Henan Normal University, Institute of Particle and Nuclear Physics, Xinxiang (China); Guo, Ya-Fei [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Zhang, Hong-Fei [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

    2017-05-15

    Within the framework of the dinuclear system model, production cross sections of proton-rich nuclei with charged numbers of Z = 84-90 are investigated systematically. Possible combinations with the {sup 28}Si, {sup 32}S, {sup 40}Ar bombarding the target nuclides {sup 165}Ho, {sup 169}Tm, {sup 170-174}Yb, {sup 175,176}Lu, {sup 174,} {sup 176-180}Hf and {sup 181}Ta are analyzed thoroughly. The optimal excitation energies and evaporation channels are proposed to produce the proton-rich nuclei. The systems are feasible to be constructed in experiments. It is found that the neutron shell closure of N = 126 is of importance during the evaporation of neutrons. The experimental excitation functions in the {sup 40}Ar induced reactions can be nicely reproduced. The charged particle evaporation is comparable with neutrons in cooling the excited proton-rich nuclei, in particular for the channels with α and proton evaporation. The production cross section increases with the mass asymmetry of colliding systems because of the decrease of the inner fusion barrier. The channels with pure neutron evaporation depend on the isotopic targets. But it is different for the channels with charged particles and more sensitive to the odd-even effect. (orig.)

  19. New approach to the nuclear in beam γ spectroscopy of neutron rich nuclei at N=20 using projectile fragmentation

    International Nuclear Information System (INIS)

    Lopez-Jimenez, M.J.; Saint-Laurent, M.G.; Achouri, L.; Daugas, J.M.; Belleguic, M.; Azaiez, F.; Bourgeois, C.; Angelique, J.C.

    1999-01-01

    The structure of nuclei far from stability around 32 Mg have been recently investigated by means of a novel method. In-beam γ-decay spectroscopy of a large number of exotic neutron-rich nuclei produced by projectile fragmentation of a 36 S projectile has been performed, using coincidences between the recoil fragments collected at the focal plane of SPEG spectrometer and γ-rays emitted at the target location. Preliminary results on both the population mechanism and the decay of excited states in nuclei around 32 Mg are presented. (author)

  20. Study on decay of rare earth nuclei produced by fission

    Energy Technology Data Exchange (ETDEWEB)

    Kawade, Kiyoshi; Yamamoto, Hiroshi; Shibata, Michihiro; Asai, Masato [Nagoya Univ. (Japan); Tsukada, Kazuaki; Osa, Akihiko; Shinohara, Nobuo; Iimura, Hideki

    1996-01-01

    JAERI-ISOL utilizes charge particle induced fission by proton and heavy proton produced by the tandem type accelerator (JAERI). To study the decay mechanism and nuclei structure of neutron and excess nuclei produced by actinoid fission, JAERI-ISOL was improved by developing the multilayer target tank. So that, the intensity of mass separated ion beam increased enough to use. New 76.6 KeV {gamma}-ray with about 10s of half life was found in the preliminary experiment. (S.Y.)

  1. Decay spectroscopy of neutron-rich nuclei with the CAITEN detector

    Energy Technology Data Exchange (ETDEWEB)

    Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration

    2012-07-01

    An experiment in fall 2010 at the RIBF (Radioactive Ion Beam Factory at RIKEN, Japan) investigated the neutron-rich nuclei in the neighborhood of {sup 30}Ne and {sup 36}Mg. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam which was delivered from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The unambiguous particle identification was achieved by measuring the energy loss, time of flight and magnetic rigidity event-by-event. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a 4 x 10{sup 4}-fold segmented plastic scintillator with the shape of a hollow cylinder. To reduce background events the scintillator was moved continuously in axial and vertical direction (similar to a tape-transporting system). Implantations and decays were correlated in time and space. {gamma}-rays were detected with three germanium clover detectors. For the first time {beta}-delayed gammas were measured in the neutron-rich isotopes {sup 36-38}Si. The status of the analysis and preliminary results including new half-life values and tentative level schemes for these very exotic nuclei are presented.

  2. Shape evolution in neutron-rich A ~ 140 nuclei beyond the doubly-magic nucleus 132Sn

    Science.gov (United States)

    Odahara, Atsuko; Eurica Collaboration

    2014-09-01

    Study for the shape evolution enables us to disentangle competition between spherical (single-particle like) shape and deformed (collective-like) shape as a function of neutron number. Neutron-rich nuclei in the northeast region of the doubly-magic 132Sn locates in one of the best mass region where a variety of collective modes, not only prolate deformation but also octupole collectivity, are expected to appear. These neutron-rich A ~140 nuclei were produced by using in-flight fission reaction of the 345 MeV/u 238U86+ beam at RIKEN RI Beam Factory. This experiment was performed in the framework of the EURICA (EUroball RIken Cluster Array) project based on the highly-efficient β- and isomer-decay spectroscopy methods. Around 20 extremely neutron-rich nuclei with Z=51--55 have been studied in this work. New isomers with half lives of longer than hundreds ns were found in some nuclei, such as the neutron-rich Cs isotopes. Also, preliminary results for the β decay of neutron-rich I and Xe isotopes have been obtained. Systematic change of the shape evolution for these neutron-rich isotopes will be discussed.

  3. Two-proton radioactivity in proton-rich fp shell nuclei at high spin

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Mamta [Nuclear Science Centre, Aruna Asaf Ali Marg, Post Box 10502, New Delhi 110067 (India)

    2006-07-15

    Two-proton radioactivity in extremely proton-rich fp shell nuclei at high spins is investigated in a theoretical framework. Separation energy and entropy fluctuate with spin and hence affect the location of the proton drip line.

  4. Two-proton radioactivity in proton-rich fp shell nuclei at high spin

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2006-01-01

    Two-proton radioactivity in extremely proton-rich fp shell nuclei at high spins is investigated in a theoretical framework. Separation energy and entropy fluctuate with spin and hence affect the location of the proton drip line

  5. Decay spectroscopy of neutron-rich nuclei around {sup 37,38}Al

    Energy Technology Data Exchange (ETDEWEB)

    Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration

    2013-07-01

    An experiment at RIBF (Radioactive Isotope Beam Factory at RIKEN, Japan) investigated N=20 nuclei above {sup 29}F and the midshell region around {sup 37}Al. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a highly segmented plastic scintillator with the shape of a hollow cylinder. To reduce background decay events the scintillator was moved axially and vertically similar to a tape-transport system. Implantations and decays were correlated in time and space. For the first time β-delayed γ-rays were measured in the neutron-rich isotopes {sup 37,38}Si (with three germanium clover detectors). From β-γ-γ coincidences partial level schemes could be constructed. The results were compared to shell model calculations and a tentative assignment for spins and parities of the experimental level schemes was possible. Significantly more precise half-lives for the implanted nuclei were measured.

  6. Method of producing excited states of atomic nuclei

    International Nuclear Information System (INIS)

    Morita, M.; Morita, R.

    1976-01-01

    A method is claimed of producing excited states of atomic nuclei which comprises bombarding atoms with x rays or electrons, characterized in that (1) in the atoms selected to be produced in the excited state of their nuclei, (a) the difference between the nuclear excitation energy and the difference between the binding energies of adequately selected two electron orbits is small enough to introduce the nuclear excitation by electron transition, and (b) the system of the nucleus and the electrons in the case of ionizing an orbital electron in said atoms should satisfy the spin and parity conservation laws; and (2) the energy of the bombarding x rays or electrons should be larger than the binding energy of one of the said two electron orbits which is located at shorter distance from the atomic nucleus. According to the present invention, atomic nuclei can be excited in a relatively simple manner without requiring the use of large scale apparatus, equipment and production facilities, e.g., factories. It is also possible to produce radioactive substances or separate a particular isotope with an extremely high purity from a mixture of isotopes by utilizing nuclear excitation

  7. Mirror energy difference and the structure of loosely bound proton-rich nuclei around A =20

    Science.gov (United States)

    Yuan, Cenxi; Qi, Chong; Xu, Furong; Suzuki, Toshio; Otsuka, Takaharu

    2014-04-01

    The properties of loosely bound proton-rich nuclei around A =20 are investigated within the framework of the nuclear shell model. In these nuclei, the strength of the effective interactions involving the loosely bound proton s1/2 orbit is significantly reduced in comparison with that of those in their mirror nuclei. We evaluate the reduction of the effective interaction by calculating the monopole-based-universal interaction (VMU) in the Woods-Saxon basis. The shell-model Hamiltonian in the sd shell, such as USD, can thus be modified to reproduce the binding energies and energy levels of the weakly bound proton-rich nuclei around A =20. The effect of the reduction of the effective interaction on the structure and decay properties of these nuclei is also discussed.

  8. Production and identification of new, neutron-rich nuclei in the {sup 208}Pb region

    Energy Technology Data Exchange (ETDEWEB)

    Rykaczewski, K. [Oak Ridge National Lab., TN (United States). Physics Div.]|[ISOLDE-CERN, Geneva (Switzerland)]|[Univ. of Warsaw (Poland); Kurpeta, J.; Plochocki, A. [Univ. of Warsaw (Poland)] [and others

    1998-11-01

    The recently developed methods allowing the experimental studies on new neutron-rich nuclei beyond doubly-magic {sup 208}Pb are briefly described. An identification of new neutron-rich isotopes {sup 215}Pb and {sup 217}Bi, and new decay properties of {sup 216}Bi studied by means of a pulsed release element selective technique at PS Booster-ISOLDE are reported.

  9. Production and identification of new, neutron-rich nuclei in the 208Pb region

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Kurpeta, J.; Plochocki, A.; Karny, M.; Szerypo, J.; Evensen, A.-H.; Kugler, E.; Lettry, J.; Ravn, H.; Duppen, P. van; Andreyev, A.; Huyse, M.; Woehr, A.; Jokinen, A.; Aeystoe, J.; Nieminen, A.; Huhta, M.; Ramdhane, M.; Walter, G.; Hoff, P.

    1998-01-01

    The recently developed methods allowing the experimental studies on new neutron-rich nuclei beyond doubly-magic 208 Pb are briefly described. An identification of new neutron-rich isotopes 215 Pb and 217 Bi, and new decay properties of 216 Bi studied by means of a pulsed release element selective technique at PS Booster-ISOLDE are reported

  10. Fusion enhancement in the reactions of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Bian Baoan; Zhang Fengshou; Zhou Hongyu

    2009-01-01

    The neutron-rich fusion reactions are investigated systematically using the improved isospin dependent quantum molecular dynamics model. By studying the systematic dependence of fusion barrier on neuron excess, we find the enhancement of the fusion cross sections for neutron-rich nuclear reactions that give the lowered static Coulomb barriers. The calculated fusion cross sections agree quantitatively with the experimental data. We further discuss the mechanism of the fusion enhancement of the cross sections for neutron-rich nuclear reactions by analyzing the dynamical lowering of the Coulomb barrier that is attributed to the enhancement of the N/Z ratio at the neck region.

  11. Gamow-Teller beta decay of proton-rich nuclei

    International Nuclear Information System (INIS)

    Klepper, O.; Rykaczewski, K.

    1990-11-01

    The beta decays of 48 Mn and of even-even nuclei near the double shell-closures at 100 Sn and 146 Gd are currently investigated at the GSI on-line mass separator. Their Gamow-Teller strength are surveyed in their present experimental status, together with related results from the ISOLDE (CERN) and ISOCELE (Orsay) separators, and are compared with predictions from different nuclear models. The strength of the 0 + → 1 + Gamow-Teller transitions is compiled in tables and graphs. (orig.)

  12. Measurement of total reaction cross sections of exotic neutron rich nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Chouvel, J.M.; Wen Long, Z.

    1987-01-01

    Total reaction cross-sections of neutron rich nuclei from C to Mg in a thick Si-target have been measured using the detection of the associated γ-rays in a 4Π-geometry. This cross-section strongly increases with neutron excess, indicating an increase of as much as 15% of the reduced strong absorption radius with respect to stable nuclei

  13. Study of subshell gap around N = 70 for neutron-rich nuclei

    International Nuclear Information System (INIS)

    Hemalatha, M.

    2011-01-01

    The study and search for new regions of shell closure for nuclei away from stability is a topic of current interest both experimentally and theoretically. There have been few studies predicting a weak spherical subshell gap of 110 Zr (N = 70), for example. This is supported by a recent study indicating that the spherical N = 70 shell gap may not have a large effect at N = 68 for Zr isotopes. It would be, therefore, interesting to know whether there is a subshell closure at N = 70 in the neutron rich region and also for the very neutron-rich nuclei, 110 Zr

  14. Investigation of correlations in light neutron-rich nuclei

    International Nuclear Information System (INIS)

    Normand, G.

    2004-10-01

    Correlations play a crucial role in understanding the structure of light nuclei at and beyond the neutron drip-line. In this context, the two-neutron halo nucleus He 6 and the unbound systems H 5 , He 7,9 and Li 10 have been studied via measurements of the breakup of beams of He 6 and Be 11,12 . The CHARISSA and DEMON detector arrays were employed. The interpretation was facilitated by a simulation code (SILLAGE) which provided for the setup. In the case of He 7 , the existence of an excited state with E r ∼ 1 MeV and gamma ∼ 0.75 MeV was confirmed. The virtual character of the s-wave ground state of Li 10 was also confirmed and a scattering length of as ∼ -16 fm deduced. The results obtained for He 9 suggest that a virtual s-wave state may exist just above threshold. The study of the three-body breakup of He 6 found that the decay of the first 2+ state is essentially direct, while the decay of the remaining continuum strength is sequential - passage via He 5 . Using the technique of intensity interferometry an rms separation between the halo neutrons of 7.7 +- 0.8 fm was derived. This result was confirmed by a complementary method utilizing Dalitz plots. In the case of H 5 , the invariant mass spectrum was found to exhibit a broad (gamma ∼ 2 MeV) structure some 1.8 MeV above threshold. Comparison with recent three-body model calculations suggest that this corresponds to the predicted 1/2+ ground state. An rms valence neutron separation of some 5.5 fm was estimated. A search was also carried out for the 4n system using the Be 12* (2 alpha + Xn decay channel). No signal was observed beyond that expected on the basis of the known background processes. (author)

  15. SU(3) symmetries in exotic neutron-rich nuclei

    International Nuclear Information System (INIS)

    Hayes, A.C.

    1991-01-01

    We examine the structure of the exotic neutron-rich nucleus 11 Li with an emphasis on understanding the origin of the soft E1 resonance and the neuron halo. The similarities and differences between shell model and di-neutron cluster model descriptions of the system are displayed using the Hecht expansion techniques. We find that the ground state 11 Li as described in large shell model calculations is well approximated by the di-neutron cluster state. In contrast to the ground state, the soft E1 model of 11 Li appears to have a more complicated structure and the E1 strength of this resonance is very sensitive to cancellations between p→s and p→d contributions to the dipole matrix elements. 12 refs., 6 figs., 3 tabs

  16. Direct mass measurements of light neutron-rich nuclei using fast recoil spectrometers

    International Nuclear Information System (INIS)

    Vieira, D.J.; Wouters, J.M.

    1987-01-01

    Extensive new mass measurement capabilities have evolved with the development of recoil spectrometers. In the Z = 3 to 9 neutron-rich region alone, 12 neutron-rich nuclei have been determined for the first time by the fast-recoil direct mass measurement method. A recent experiment using the TOFI spectrometer illustrates this technique. A systematic investigation of nuclei that lie along or near the neutron-drip line has provided a valuable first glimpse into the nuclear structure of such nuclei. No evidence for a large single-particle energy gap at N = 14 is observed; however, a change in the two-neutron separation model calculations, and is interpreted in terms of the smaller 1s/sub 1/2/ - 1s/sub 1/2/ interaction compared to that of the 0d/sub 5/2/ - 0d/sub 5/2/ neutron-neutron interaction. 18 refs., 7 figs., 1 tab

  17. Neutron roton pairing effect on some even ven rare-earth proton-rich nuclei

    International Nuclear Information System (INIS)

    Mokhtari, D.

    2004-01-01

    The neutron roton pairing effect on some even ven rare-earth proton-rich nuclei is studied. It is taken into account, in the isovector case, within the framework of the generalized Bogoliubov-Valatin transformation, using Woods-Saxon single-particle energies. (author)

  18. Dipole polarizability of neutron rich nuclei and the symmetry energy

    Energy Technology Data Exchange (ETDEWEB)

    Horvat, Andrea; Johansen, Jacob; Miki, Kenjiro; Schindler, Fabia; Schrock, Philipp [IKP, TU Darmstadt (Germany); Aumann, Thomas [IKP, TU Darmstadt (Germany); GSI, Darmstadt (Germany); Boretzky, Konstanze [GSI, Darmstadt (Germany); Collaboration: R3B-Collaboration

    2015-07-01

    As a part of a systematic investigation of the dipole response of stable up to very neutron rich tin isotopes, nuclear and electromagnetic excitation of {sup 124}Sn-{sup 134}Sn has been investigated at relativistic energies in inverse kinematics induced by carbon and lead targets at the LAND-R3B setup at GSI in Darmstadt. The electric dipole response and the nuclear reaction cross section, total and charge-changing, are obtained from the kinematically complete determination of momenta of all particles on an event by event basis. The dipole polarizability is extracted from the Coulomb excitation interaction channel, in order to make use of relevant correlations of this observable with nuclear matter properties such as the symmetry energy at saturation density (J) and it's slope (L). The systematics of the low-lying ''pygmy'' dipole strength, the giant dipole resonance (GDR) and the neutron skin thickness are determined with respect to increasing isospin asymmetry. This talk also discusses the correlations and sensitivities of these variables and observables obtained within the framework of nuclear energy density functional theory.

  19. Evolution of collectivity in neutron-rich nuclei in the 132Sn region

    International Nuclear Information System (INIS)

    Kshetri, Ritesh; Sarkar, M. Saha; Sarkar, S.

    2006-01-01

    Motivated by the observed regularity in the energy spectra and the structure of the shell model wave functions for the levels of 137 Te and 137 I, a few weakly and moderately deformed neutron-rich odd-A nuclei above the doubly magic nucleus 132 Sn were studied using the particle rotor model (PRM). The calculated energy spectra and branching ratios agree reasonably well with the most recent experimental data. In a few cases ambiguity in level ordering was resolved and spin-parities were assigned to the levels. Observed octupole correlation in some of these nuclei is discussed in the light of the present results

  20. Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL: the EXILL campaign

    Directory of Open Access Journals (Sweden)

    de France G.

    2014-03-01

    Full Text Available A combination of germanium detectors has been installed at the PF1B neutron guide of the ILL to perform the prompt spectroscopy of neutron-rich nuclei produced in the neutron-capture induced-fission of 235U and 241Pu. In addition LaBr3 detectors from the FATIMA collaboration have been installed in complement with the EXOGAM clovers to measure lifetimes of low-lying excited states. The measured characteristics and online spectra indicate very good performances of the overall setup.

  1. Magicity of neutron-rich nuclei within relativistic self-consistent approaches

    Directory of Open Access Journals (Sweden)

    Jia Jie Li

    2016-02-01

    Full Text Available The formation of new shell gaps in intermediate mass neutron-rich nuclei is investigated within the relativistic Hartree–Fock–Bogoliubov theory, and the role of the Lorentz pseudo-vector and tensor interactions is analyzed. Based on the Foldy–Wouthuysen transformation, we discuss in detail the role played by the different terms of the Lorentz pseudo-vector and tensor interactions in the appearing of the N=16, 32 and 34 shell gaps. The nuclei 24O, 48Si and 52,54Ca are predicted with a large shell gap and zero (24O, 52Ca or almost zero (48Si, 54Ca pairing gap, making them candidates for new magic numbers in exotic nuclei. We find from our analysis that the Lorentz pseudo-vector and tensor interactions induce very specific evolutions of single-particle energies, which could clearly sign their presence and reveal the need for relativistic approaches with exchange interactions.

  2. Fifth International Conference on Fission and Properties of Neutron-Rich Nuclei

    CERN Document Server

    Ramayya, A V; ICFN5

    2014-01-01

    These proceedings are the fifth in the series of International Conferences covering fission and properties of neutron-rich nuclei, which are at the forefront of nuclear research. The time interval of 5 years between each conference allows for significant new results to be achieved. Recently, world leaders in theory and experiments in research and the development of new facilities for research presented their latest results in areas such as synthesis of superheavy elements, new facilities for and recent results with radioactive ion beams, structure of neutron-rich nuclei, nuclear fission process, fission yields and nuclear astrophysics. This book is a major source of the latest research in these areas and plans for the future. The conference brought together a unique group of over 100 speakers including leaders from the major nuclear laboratories in Canada, China, France, Finland, Germany, Italy, Japan, Russia, Switerzland and the US along with leading research scientists from around the world.

  3. Structure of neutron-rich nuclei around the N = 50 shell-gap closure

    Science.gov (United States)

    Faul, T.; Duchêne, G.; Thomas, J.-C.; Nowacki, F.; Huyse, M.; Van Duppen, P.

    2010-04-01

    The structure of neutron-rich nuclei in the vicinity of 78Ni have been investigated via the β-decay of 71,73,75Cu isotopes (ISOLDE, CERN). Experimental results have been compared with shell-model calculations performed with the ANTOINE code using a large (2p3/21f5/22p1/21g9/2) valence space and a 56/28Ni28 core.

  4. Gamma rays and neutrinos from the Crab Nebula produced by pulsar accelerated nuclei

    OpenAIRE

    Bednarek, W.; Protheroe, R. J.

    1997-01-01

    We investigate the consequences of the acceleration of heavy nuclei (e.g. iron nuclei) by the Crab pulsar. Accelerated nuclei can photodisintegrate in collisions with soft photons produced in the pulsar's outer gap, injecting energetic neutrons which decay either inside or outside the Crab Nebula. The protons from neutron decay inside the nebula are trapped by the Crab Nebula magnetic field, and accumulate inside the nebula producing gamma-rays and neutrinos in collisions with the matter in t...

  5. Process to produce excited states of atomic nuclei

    International Nuclear Information System (INIS)

    Morita, M.; Morita, R.

    The claims of a patented process which relates to the production of excited states of atomic nuclei are outlined. Among these are (1) production of nuclear excited states by bombarding the atoms with x rays or electrons under given conditions, (2) production of radioactive substances by nuclear excitation with x rays or electrons, (3) separation of specific isotopes from a mixture of isotopes of the same element by means of nuclear excitation followed by chemical treatment. The invention allows production of excited states of atomic nuclei in a relatively simple manner without the need of large apparatus and equipment

  6. Cluster-transfer reactions with radioactive beams: a spectroscopic tool for neutron-rich nuclei

    CERN Document Server

    AUTHOR|(CDS)2086156; Raabe, Riccardo; Bracco, Angela

    In this thesis work, an exploratory experiment to investigate cluster-transfer reactions with radioactive beams in inverse kinematics is presented. The aim of the experiment was to test the potential of cluster-transfer reactions at the Coulomb barrier, as a possible mean to perform $\\gamma$ spectroscopy studies of exotic neutron-rich nuclei at medium-high energies and spins. The experiment was performed at ISOLDE (CERN), employing the heavy-ion reaction $^{98}$Rb + $^{7}$Li at 2.85 MeV/A. Cluster-transfer reaction channels were studied through particle-$\\gamma$ coincidence measurements, using the MINIBALL Ge array coupled to the charged particle Si detectors T-REX. Sr, Y and Zr neutron-rich nuclei with A $\\approx$ 100 were populated by either triton- or $\\alpha$ transfer from $^{7}$Li to the beam nuclei and the emitted complementary charged fragment was detected in coincidence with the $\\gamma$ cascade of the residues, after few neutrons evaporation. The measured $\\gamma$ spectra were studied in detail and t...

  7. Coulomb Excitation of Neutron-Rich $A\\approx$140 Nuclei

    CERN Multimedia

    Van duppen, P L E

    2002-01-01

    Investigating the isospin dependence of the product between the B( E2; 0$_{1}^{+} \\rightarrow 2_{1}^{+}$)-value and the 2$_{1}^{+}$-excitation energy E$_{2^{+}}$ in even-even nuclei around $A\\!\\approx$140 one observes a rather smooth trend close to the valley of stability but clear indication for a reduction from the extrapolated B(E2)-values by one order of magnitude for some very neutron-rich nuclei. While close to the valley of stability the strong neutron-proton interaction results in an equilibration of the neutron and proton deformations with a predominate isoscalar character of the collective 2$^{+}$ excitation, it is conceivable that more loosely bound neutrons cannot polarize a close-to-magic proton core that well any more. This might result in a decoupling of the shape of the outer neutrons from the core and in a strong isovector admixture to the lowest lying 2$^{+}$ level. In this way the 2$^{+}$ -energies could be further lowered in neutron-rich nuclei, while the quadrupole moments of the proton c...

  8. Study of the Beta-Decay Properties of Extremely Proton-Rich Nuclei

    CERN Multimedia

    2002-01-01

    The most proton-rich nuclei known to date have isospin projections $ T _{Z} $ ~=~-3/2, -2 and -5/2. \\\\ \\\\ We propose to carry out a study of their superallowed beta decays, a phenomenon that can only be studied in this region of the nuclear chart. The main aim is to determine the ``effective charge'' in nuclei of the axial vector coupling, the quantity $ ( g'_{A} / g _{A} ) ^{2} $ , which in a recent first experiment on a ~~ $ T _{Z} $~~=~-2 nucleus was determined to be 0.49~$\\pm$~0.05. \\\\ \\\\ Because of the problems connected with the production and acceleration of radioactive ions, our proposal aims at selected elements: neon, argon and rubidium (production runs), magnesium (test and production runs) and calcium (test). Data have so far been taken for $^1

  9. Unstable states produced in collisions among complex nuclei

    International Nuclear Information System (INIS)

    Sepulveda J, D.

    1978-01-01

    A theory about resonant elastic dispersion is formulated and the wave function of unstable states associated with the resonances observed in the differential and total sections is studied. The object of this theory is to extend to the elastic collisions among complex nuclei interesting case, the methods and formalism of the dispersion of particles without structure by an external potential, following an idea originally formulated by H. Feshbach. (author)

  10. Decay of Hot Nuclei at Low Spins Produced by Antiproton-Annihilation in Heavy Nuclei

    CERN Multimedia

    2002-01-01

    % PS208 \\\\ \\\\ The objective of the experiment is to study (i) the thermal excitation energy distribution of antiproton-induced reactions in heavy nuclei and (ii) the decay properties of hot nuclei at low spins via evaporation, multifragmentation and fission as a function of excitation energy. The experimental set-up consists of 4-$\\pi$ detectors: the Berlin Neutron Ball~(BNB) which is a spherical shell of gadolinium-loaded scintillator liquid with an inner and outer diameter of 40 and 160~cm, respectively. This detector counts the number of evaporated neutrons in each reaction. Inside BNB there is a 4-$\\pi$ silicon ball~(BSIB) with a diameter of 20~cm consisting of 162 detectors which measure energy and multiplicity of all emitted charged nuclear particles. The particles are identified via time of flight, energy and pulse shape correlations.

  11. Spectroscopy on neutron-rich nuclei at RIKEN. Present and future

    International Nuclear Information System (INIS)

    Sakurai, H.

    2003-01-01

    Recent studies on nuclear structure by using radioactive isotope beams available at the RIKEN projectile-fragment separator (RIPS) are introduced. Special emphasis is given to experiments selected from the recent programs that highlight studies at N=20-28; on the large deformation of 30 Ne and 34 Mg via the in-beam gamma spectroscopy, and on the particle stability of very neutron-rich nuclei, 34 Ne, 37 Na and 43 Si. The RI Beam Factory (RIBF) project is illustrated through review of such present research activities at RIPS. (author)

  12. Simulation of neutron rich nuclei production through 239U fission at intermediates energies

    International Nuclear Information System (INIS)

    Mirea, M.; Clapier, F.; Pauwels, N.; Proust, J.

    1997-01-01

    The theoretical part and some results obtained from a model realised for fission processes in wide range of mass-asymmetries are presented. The fission barriers are computed in a tridimensional configuration space using the Yukawa - plus - exponential macroscopic energies corrected within the Strutinsky procedure. It is assumed that channel probabilities are proportional with Gamow penetrabilities. The model is applied for the disintegration of the 239 U in order to determine the relative yields for the production of neutron rich nuclei at diverse intermediate energies. (author)

  13. Collective excitations in neutron-rich nuclei within the model of a Fermi liquid drop

    International Nuclear Information System (INIS)

    Kolomietz, V.M.; Magner, A.G.

    2000-01-01

    We discuss a new mechanism of splitting of giant multipole resonances (GMR) in spherical neutron-rich nuclei. This mechanism is associated with the basic properties of an asymmetric drop of nuclear Fermi liquid. In addition to well-known isospin shell-model predictions, our approach can be used to describe the GMR splitting phenomenon in the wide nuclear-mass region A ∼ 40-240. For the dipole isovector modes, the splitting energy, the relative strength of resonance peaks, and the contribution to the energy-weighted sum rules are in agreement with experimental data for the integrated cross sections for photonuclear (γ, n) and (γ, p) reactions

  14. Exotic octupole deformation in proton-rich Z=N nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Satoshi; Yabana, K [Niigata Univ. (Japan); Matsuo, M

    1998-03-01

    We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)

  15. Nucleosynthesis of proton-rich nuclei. Experimental results on the rp-process

    International Nuclear Information System (INIS)

    Galaviz, D; Amthor, A M; Bazin, D; Becerril, A D; Brown, B A; Cole, A; Cook, J M; Elliot, T; Estrade, A; Gade, A; Glasmacher, T; Lorusso, G; Matos, M; Montes, F; Mueller, W; Chen, A A; Fueloep, Z S; Heger, A; Howard, M E; Kessler, R

    2010-01-01

    We report in this study the nuclear properties of proton-rich isotopes located along the rp-process path. The experiments have recently been performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The level properties above the proton separation energy of the nuclei 30 S, 36 K and 37 Ca were measured with precision of < 10 keV. This will allow a reduction in the determination of the astrophysical (p,γ) reaction rate under rp-process conditions.

  16. Symmetry energy and surface properties of neutron-rich exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gaidarov, M. K.; Antonov, A. N. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Sarriguren, P. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 123, E-28006 Madrid (Spain); Moya de Guerra, E. [Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2014-07-23

    The symmetry energy, the neutron pressure and the asymmetric compressibility of spherical Ni, Sn, and Pb and deformed Kr and Sm neutron-rich even-even nuclei are calculated within the coherent density fluctuation model using the symmetry energy as a function of density within the Brueckner energy-density functional. The correlation between the thickness of the neutron skin and the characteristics related with the density dependence of the nuclear symmetry energy is investigated for isotopic chains of these nuclei in the framework of the deformed self-consistent mean-field Skyrme HF+BCS method. The mass dependence of the nuclear symmetry energy and the neutron skin thickness are also studied together with the role of the neutron-proton asymmetry. The studied correlations reveal a smoother behavior in the case of spherical nuclei than for deformed ones. We also notice that the neutron skin thickness obtained for {sup 208}Pb with SLy4 force is found to be in a good agreement with the recent data. In addition to the interest that this study may have by itself, we give some numerical arguments in proof of the existence of peculiarities of the studied quantities in Ni and Sn isotopic chains that are not present in the Pb chain.

  17. New mass analysis and results for neutron rich nuclei performed with isochronous mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Diwisch, Marcel [Justus-Liebig-Universitaet Giessen, Giessen (Germany); Knoebel, Ronja; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [Justus-Liebig-Universitaet Giessen, Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Patyk, Zygmunt [Soltan Institute for Nuclear Studies, Warsaw (Poland); Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2015-07-01

    The Isochronous Mass Spectrometry (IMS) allows to measure masses of rare exotic nuclei in a storage ring in a timescale of tens of μs. The ring is operated in an isochronous mode, i.e. such that particles with different velocities but same mass-to-charge ratio (m/q) travel different paths in the ring arcs (faster ions travel longer paths whereas slower ions travel shorter paths). This means that for each m/q a fix revolution time exists and can be measured by a time-of-flight (TOF) detector which then yields the masses of the nuclei for known charge states. A new analysis approach of IMS data with a correlation matrix method allowed combining data with different quality. The latest production run was using an additional determination of the magnetic rigidity which increased the resolving power of the experiment. Combining this experiment with previous experiments one can increase the statistics and accuracy of the overall mass determination. It was possible to deduce mass values of neutron rich isotopes which have not been measured before. One of those isotopes is {sup 130}Cd which is a very important nuclei involved in the r-process. Those mass values and a comparison to theoretical predictions will be presented in the poster.

  18. Statistical properties of warm nuclei: Investigating the low-energy enhancement in the $\\gamma$- strength function of neutron-rich nuclei

    CERN Multimedia

    We propose to start a program to study the $\\gamma$-ray strength function of neutron rich nuclei in inverse kinematics with radioactive beams at HIE-ISOLDE. An unexpected increase in the $\\gamma$-strength function at low energy has been observed in several stable nuclei using the Oslo method. This year these results were confirmed with a different experimental technique and model independent analysis developed by iThemba/Livermore. If this enhancement of the $\\gamma$-strength function is also present in neutron-rich nuclei, it will strongly affect the neutron capture cross sections, which are important input in stellar models of synthesis of heavier elements in stars. We propose to start with an experiment using a $^{66}$Ni beam of 5.5 MeV /u, where the data will be analyzed using both methods independently, and we are sure to get enough statistics, before moving to more neutron-rich nuclei. When/if neutron-rich Ti, Fe or Mo beams will be available at ISOLDE, we will submit additional proposals.

  19. Decay of hot nuclei produced by relativistic light ions

    International Nuclear Information System (INIS)

    Karnaukhov, V.A.; Avdeev, S.P.; Kuznetsov, V.D.

    1995-01-01

    In collisions of light relativistic projectiles (p, 4 He) with heavy nuclei (Au) very excited target spectators are created, which decay via multiple emission of intermediate mass fragments. It was found that the mean IMF multiplicities are equal (within 15%) to 2.0, 2.6 and 3.0 at proton energies 2.16, 3.6 and 8.1 GeV respectively. These values are comparable with those obtained with heavy ions in the same beam energy range. This is considered to indicate that this observable is not sensitive to the collision dynamics and is determined by the phase space factor. IMF energy spectra are described by the statistical model of multifragmentation neglecting dynamics of the expansion stage before the break up. The expansion velocity is estimated to be ≤ 0.02 c. The mean lifetime of a fragmentating system is found to be ≤ 75 fm/c from IMF-IMF-angular correlations for 4 He (14.6 GeV) +Au collisions. The results support a scenario of true 'thermal' multifragmentation. 26 refs., 10 figs., 1 tab

  20. Antisymmetrized molecular dynamics studies for exotic clustering phenomena in neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, M. [Hokkaido University, Department of Physics, Sapporo (Japan); Hokkaido University, Nuclear Reaction Data Centre, Faculty of Science, Sapporo (Japan); Suhara, T. [Matsue College of Technology, Matsue (Japan); Kanada-En' yo, Y. [Kyoto University, Department of Physics, Kyoto (Japan)

    2016-12-15

    We present a review of recent works on clustering phenomena in unstable nuclei studied by antisymmetrized molecular dynamics (AMD). The AMD studies in these decades have uncovered novel types of clustering phenomena brought about by the excess neutrons. Among them, this review focuses on the molecule-like structure of unstable nuclei. One of the earliest discussions on the clustering in unstable nuclei was made for neutron-rich Be and B isotopes. AMD calculations predicted that the ground state clustering is enhanced or reduced depending on the number of excess neutrons. Today, the experiments are confirming this prediction as the change of the proton radii. Behind this enhancement and reduction of the clustering, there are underlying shell effects called molecular and atomic orbits. These orbits form covalent and ionic bonding of the clusters analogous to the atomic molecules. It was found that this ''molecular-orbit picture'' reasonably explains the low-lying spectra of Be isotopes. The molecular-orbit picture is extended to other systems having parity asymmetric cluster cores and to the three cluster systems. O and Ne isotopes are the candidates of the former, while the 3α linear chains in C isotopes are the latter. For both subjects, many intensive studies are now in progress. We also pay a special attention to the observables which are the fingerprint of the clustering. In particular, we focus on the monopole and dipole transitions which are recently regarded as good probe for the clustering. We discuss how they have and will reveal the exotic clustering. (orig.)

  1. Interplay between collective and single particle excitations around neutron-rich doubly-magic nuclei

    Directory of Open Access Journals (Sweden)

    Leoni S.

    2016-01-01

    Full Text Available The excitation spectra of nuclei with one or two particles outside a doubly-magic core are expected to be dominated, at low energy, by the couplings between phonon excitations of the core and valence particles. A survey of the experimental situation is given for some nuclei lying in close proximity of neutron-rich doubly-magic systems, such as 47,49Ca, 133Sb and 210Bi. Data are obtained with various types of reactions (multinucleon transfer with heavy ions, cold neutron capture and neutron induced fission of 235U and 241Pu targets, with the employment of complex detection systems based on HPGe arrays. A comparison with theoretical calculations is also presented, in terms of large shell model calculations and of a phenomenological particle-phonon model. In the case of 133Sb, a new microscopic “hybrid” model is introduced: it is based on the coupling between core excitations (both collective and non-collective of the doubly-magic core and the valence nucleon, using the Skyrme effective interaction in a consistent way.

  2. Interplay between collective and single particle excitations around neutron-rich doubly-magic nuclei

    Science.gov (United States)

    Leoni, S.

    2016-05-01

    The excitation spectra of nuclei with one or two particles outside a doubly-magic core are expected to be dominated, at low energy, by the couplings between phonon excitations of the core and valence particles. A survey of the experimental situation is given for some nuclei lying in close proximity of neutron-rich doubly-magic systems, such as 47,49Ca, 133Sb and 210Bi. Data are obtained with various types of reactions (multinucleon transfer with heavy ions, cold neutron capture and neutron induced fission of 235U and 241Pu targets), with the employment of complex detection systems based on HPGe arrays. A comparison with theoretical calculations is also presented, in terms of large shell model calculations and of a phenomenological particle-phonon model. In the case of 133Sb, a new microscopic "hybrid" model is introduced: it is based on the coupling between core excitations (both collective and non-collective) of the doubly-magic core and the valence nucleon, using the Skyrme effective interaction in a consistent way.

  3. Structure of light proton-rich nuclei on the drip-line

    International Nuclear Information System (INIS)

    Guimaraes, V.; Toyokawa, H.; Yun, C.C.; Niizeki, T.; Ito, K.; Kishida, T.; Kubo, T.; Pu, Y.; Ohura, M.; Orihara, H.; Terakawa, T.; Hamada, S.; Hirai, M.; Miyatake, H.

    1995-01-01

    Among proton-rich unstable nuclei on the light proton drip-line, nuclear structure of 21 Mg, 17 Ne, 13 O, 11 N and 9 C have been investigated by the three-neutron pick-up reaction ( 3 He, 6 He). The angular distributions measured for this reaction have shown a characteristic feature of a transferred angular-momentum (L) dependence, which provides spin-parity assignments for the new levels in these nuclei. Here, the results on the nuclear structure of 17 Ne and 11 N are reported. The nucleus 17 Ne we almost unknown before, except that the mass excess had been determined and a few states had been suggested. Many T = 3/2 states were known in the other three members ( 17 N, 17 O and 17 F). Thus, the inclusion of the data on 17 Ne levels has enabled an extensive analysis in terms of the Isobaric Multiplet Mass Equation (IMME) for several excited state quartets. This is the first report on such an extensive analysis in the same mass ststem for a wide range in excitation energy. The 11 N nucleus was investigated to learn about the structure of A 11 system. This mass has been intensively studied, specially because of the halo structure observed in 11 Li and the spin parity-inversion of the 11 Be ground-state. The 11 N nucleus was totally unknown before except for the possible ground state

  4. Spectroscopy of proton-rich nuclei in the rare earth region

    International Nuclear Information System (INIS)

    Toth, K.S.; Nitschke, J.M.; Vierinen, K.S.; Wilmarth, P.A.; Firestone, R.B.; Kortelahti, M.O.

    1990-01-01

    The isotope separator facility OASIS, on-line at the Lawrence Berkeley Laboratory SuperHILAC, was used to investigate proton-rich rare earth nuclei. Single-particle states near the 82-neutron shell were delineated, numerous new isotopes, isomers, and β-delayed proton emitters were discovered and the α-decay properties of some nuclides with N > 84 were reexamined. In this contribution the experimental program is summarized briefly, the excitation energies of the s 1/2 and h 11/2 proton states in this mass region are discussed, and results on the β-delayed-proton spectra of 145 Dy and 147 Er are presented. 17 refs., 5 figs

  5. Half-lives of cluster decay of neutron rich nuclei in trans-tin region

    International Nuclear Information System (INIS)

    Swamy, G.S.; Umesh, T.K.

    2011-01-01

    In this work, the logarithmic half-life [log 10 (T 1/2 )] values have been reported for the exotic decay of some neutron rich even–even parent nuclei (56≤Z≤64) accompanied by the emission of alpha-like and non-alpha-like clusters in the trans-tin region. These values were calculated by using the single line of universal curve (UNIV) for alpha and cluster radioactive decay as well as the universal decay law (UDL). The half-life values were also separately calculated by considering the interacting nuclear potential barrier as the sum of Coulomb and proximity potentials. The half-life values based on the three calculations mentioned above, were found to agree with one another within a few orders of magnitude. Possible conclusions are drawn based on the present study. (author)

  6. Fusion reaction around the Coulomb barrier with neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Atsushi [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1997-07-01

    Two fusion reactions with neutron-rich nuclei are reported in this work. On the first reaction: {sup 9,10,11}Be+{sup 209}Bi, the fusion cross sections around the coulomb barrier were measured by determing {alpha} disintegration from compound nucleus Fr. In the field of 10-100 mb, the same total fusion cross sections were obtained. The phenomenon {sup 11}Be(neutron halo nucleus) alone increased and decreased was not observed. The fusion cross sections of {sup 27,29,31}Al+{sup 197}Au system were determined by using 130 kcps and 30 kcps of beam strength of {sup 29,31}Al, respectively. The value of {sup 27}Al was reproduced by calculation, but that of {sup 29}Al increased around barrier which could not be explained by CCDEF calculation. (S.Y.)

  7. Secondary reactions as a tool to produce exotic nuclei

    International Nuclear Information System (INIS)

    Dufour, J.P.; Fleury, A.; Bimbot, R.

    1980-01-01

    The possibility of using secondary reactions as tool to produce new isotopes is considered. This question is renewed with the emergence of intense beams of energetic heavy ions in the range of 20 to 100 MeV/nucleon. Three different methods are considered. They involve either the 'in situ' production of a secondary radioactive target, which interacts with the primary beam, or the production of a radioactive secondary beam by an inverse fusion or a fragmentation process. Very heavy or very neutron deficient isotopes can be produced by these methods

  8. Production of neutron-rich nuclei at 200 MeV/nucleon

    International Nuclear Information System (INIS)

    Symons, T.J.M.

    1979-01-01

    Ways that heavy ion accelerators have been used to produce neutron rich isotopes are discussed. These include: fusion-evaporation reactions; transfer reactions; deep-inelastic scattering; and heavy ion fragmentation. Experiments using beams of 40 Ar and 48 Ca at 205 MeV/nucleon and 212 MeV/nucleon respectively, are described

  9. Low-lying dipole strength of neutron-rich 'island of inversion' nuclei around n ∼ 20

    International Nuclear Information System (INIS)

    Datta Pramanik, U.; Chakraborty, S.; Ray, I.

    2009-01-01

    Magic numbers are the basic building blocks of nuclear structure since last fifty years. Recently, through various experimental results using Radioactive Ion Beam (RIB) facilities, it has been observed that those long cherished magic numbers are not valid anymore in the neutron rich nuclei like 32 Mg etc. The breakdown of magic number was hinted in the late 1980 's by Thibault et. al. in sodium nuclei ( 31,32 Na). Motobayashi et. al. showed large deformation for 32 Mg which leads to the failure of magic number at N = 20. Exploration into the cause of this breakdown shows the filling of higher pf orbitals rather than the pure lower sd orbitals in the ground state of the neutron-rich nuclei like Ne, Na, Mg in the region N∼20. Thus there is obviously an inversion in nuclear orbitals and hence the so called name 'island of inversion'. This year, we have performed an experiment at GSI, Darmstadt. The measurement of dipole threshold strength of neutron-rich nucleus (N∼20) through electromagnetic excitation was done using LAND-FRS setup. Through this dipole strength, we would like to probe directly the quantum numbers of the valence neutrons in neutron rich nuclei like 31-33 Mg, 33-35 Al, 29-30 Na, 25-27 Ne, 24 F etc.

  10. nuclei

    Directory of Open Access Journals (Sweden)

    Minkov N.

    2016-01-01

    Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

  11. Quasifree (p ,p N ) scattering of light neutron-rich nuclei near N =14

    Science.gov (United States)

    Díaz Fernández, P.; Alvarez-Pol, H.; Crespo, R.; Cravo, E.; Atar, L.; Deltuva, A.; Aumann, T.; Avdeichikov, V.; Beceiro-Novo, S.; Bemmerer, D.; Benlliure, J.; Bertulani, C. A.; Boillos, J. M.; Boretzky, K.; Borge, M. J. G.; Caamaño, M.; Cabanelas, P.; Caesar, C.; Casarejos, E.; Catford, W.; Cederkäll, J.; Chartier, M.; Chulkov, L. V.; Cortina-Gil, D.; Datta Pramanik, U.; Dillmann, I.; Elekes, Z.; Enders, J.; Ershova, O.; Estradé, A.; Farinon, F.; Fernández-Domínguez, B.; Fraile, L. M.; Freer, M.; Galaviz, 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.; Jurčiukonis, D.; 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.; Marganiec, J.; Moro, A. M.; Movsesyan, A.; Nacher, E.; Najafi, A.; Nikolskii, E.; Nilsson, T.; Nociforo, C.; Panin, V.; Paschalis, S.; Perea, A.; Petri, M.; Pietras, B.; Pietri, S.; Plag, R.; Reifarth, R.; Ribeiro, G.; Rigollet, C.; Rossi, D.; Röder, M.; Savran, D.; Scheit, H.; Simon, H.; Sorlin, O.; Syndikus, I.; Taylor, J. T.; Tengblad, O.; Thies, R.; Togano, Y.; Vandebrouck, M.; Velho, P.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Wheldon, C.; Wilson, G.; Winfield, J. S.; Woods, P.; Yakorev, D.; Zhukov, M.; Zilges, A.; Zuber, K.; R3B Collaboration

    2018-02-01

    Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The R 3B collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable 12C beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p ,p n ) and (p ,2 p ) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N =14 to N =15 . Method: The structure of the projectiles 23O, 22O, and 21N has been studied simultaneously via (p ,p n ) and (p ,2 p ) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the R3B -LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p ,p n ) and (p ,2 p ) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p ,p n ) channels, indications of a change in the structure of these nuclei moving from N =14 to N =15 have been observed, i.e., from the 0 d5 /2 shell to the 1 s1 /2 . This supports previous observations of a subshell closure at N =14 for neutron-rich oxygen isotopes and its weakening

  12. Studies of exotic nuclei

    International Nuclear Information System (INIS)

    Angelique, J.C.; Orr, N.A.

    1997-01-01

    The study of the nuclei far off stability valley is of much interest for testing the nuclear models established for the stable nuclei but also for astrophysics to understand the nucleosynthesis. Experiments aim to measure the mass and lifetime, to build the decay schemes and also to study the structure and the properties of these nuclei. The radioactive beam group focused its research on light neutron-rich nuclei having a halo neutron structure. Mass measurements in N ∼ Z nuclei namely in A ∼ 60-80 proton-rich nuclei, important for understanding the rp process, are mentioned, as well as in nuclei in the 100 Sn region. In the newly obtained 26 O and 28 O nuclei the lifetimes, the probabilities of emission of one for more neutrons were determined. The data analysis has permitted to determine also for the first time the lifetimes of 27,29 F and 30 Ne. Studies of nuclei in the 100 Sn region, near the proton drip line in the ground and isomeric states are now under way. The spectroscopy (energy levels, gamma emissions, etc.) of the neutron-rich nuclei produced by the 36 S fragmentation has been carried out in 31 Ne, 17 B and 29 F. Studies by Coulomb excitation of the 2 + excited states and associated probability B (E2) in O, Ne, Ni and Zn are now analysed

  13. Nuclear shell effects in neutron-rich nuclei around N=20 and N=32,34

    CERN Document Server

    Seidlitz, M

    Nuclear shell effects in neutron-rich nuclei around N=20 and N=32,34 were studied by means of reduced transition probabilities, i.e. B(E2) and B(M1) values. To this end a series of Coulomb-excitation experiments, employing radioactive 31Mg and 29,30Na beams, as well as a precise lifetime experiment of excited states in 56Cr were performed. The collective properties of excited states of 31Mg were the subject of a Coulomb-excitation experiment at REX-ISOLDE, CERN, employing a radioactive 31Mg beam at a beam energy of 3.0 MeV/u. The beam intensity amounted to 3000 ions/s on average. The highly efficient MINIBALL setup was employed, consisting of eight HPGe cluster detectors for gamma-ray detection and a segmented Si-detector for coincident particle detection. The level scheme of 31Mg was extended. Spin and parity assignment of the observed 945 keV state yielded 5/2+ and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of 30,31,32Mg establishes that f...

  14. Shape of 44Ar: Onset of deformation in neutron-rich nuclei near 48Ca

    International Nuclear Information System (INIS)

    Zielinska, M.; Goergen, A.; Clement, E.; Korten, W.; Dossat, C.; Ljungvall, J.; Obertelli, A.; Theisen, Ch.; Delaroche, J.-P.; Girod, M.; Buerger, A.; Catford, W.; Iwanicki, J.; Napiorkowski, P. J.; Srebrny, J.; Wrzosek, K.; Libert, J.; PiePtak, D.; Rodriguez-Guzman, R.; Sletten, G.

    2009-01-01

    The development of deformation and shape coexistence in the vicinity of doubly magic 48 Ca, related to the weakening of the N=28 shell closure, was addressed in a low-energy Coulomb excitation experiment using a radioactive 44 Ar beam from the SPIRAL facility at GANIL. The 2 1 + and 2 2 + states in 44 Ar were excited on 208 Pb and 109 Ag targets at two different beam energies. B(E2) values between all observed states and the spectroscopic quadrupole moment of the 2 1 + state were extracted from the differential Coulomb excitation cross sections, indicating a prolate shape of the 44 Ar nucleus and giving evidence of an onset of deformation already two protons and two neutrons away from doubly magic 48 Ca. New Hartree-Fock-Bogoliubov based configuration mixing calculations have been performed with the Gogny D1S interaction for 44 Ar and neighboring nuclei using two different approaches: the angular momentum projected generator coordinate method considering axial quadrupole deformations and a five-dimensional approach including the triaxial degree of freedom. The experimental values and new calculations are furthermore compared to shell-model calculations and to relativistic mean-field calculations. The new results give insight into the weakening of the N=28 shell closure and the development of deformation in this neutron-rich region of the nuclear chart.

  15. New experimental investigation of cluster structures in 10 Be and 16 C neutron-rich nuclei

    Science.gov (United States)

    Dell'Aquila, L.; Acosta, D.; Auditore, L.; Cardella, G.; De Filippo, E.; De Luca, S.; Francalanza, L.; Gnoffo, B.; Lanzalone, G.; Lombardo, I.; Martorana, N. S.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Quattrocchi, L.; Rizzo, F.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Vigilante, M.

    2017-11-01

    The existence of cluster structures in ^{10} Be and ^{16} C neutron-rich isotopes is investigated via projectile break-up reactions induced on polyethylene (CH _2 target. We used a fragmentation beam constituted by 55MeV/u ^{10} Be and 49MeV/u ^{16} C beams provided by the FRIBs facility at INFN-LNS. Invariant mass spectra of 4{He}+ 6 He and 6{He} + ^{10} Be breakup fragments are reconstructed by means of the CHIMERA 4π detector to investigate the presence of excited states of projectile nuclei characterized by cluster structure. In the first case, we suggest the presence of a new state in ^{10} Be at 13.5MeV. A non-vanishing yield corresponding to 20.6MeV excitation energy of ^{16} C was observed in the 6{He} + ^{10} Be cluster decay channel. To improve the results of the present analysis, a new experiment has been performed recently, taking advantage of the coupling of CHIMERA and FARCOS. In the paper we describe the data reduction process of the new experiment together with preliminary results.

  16. Study of Beta-Delayed Neutron Emission by Neutron-Rich Nuclei and Analysis of the Nuclear Reaction Mechanism responsible for the Yields of these Nuclei

    International Nuclear Information System (INIS)

    Bazin, D.

    1987-07-01

    Among the nuclear mechanisms used for the production of nuclei far from stability, the projectile fragmentation process has recently proved its efficiency. However, at Fermi energies, one has to take into account some collective and relaxation effects which drastically modify the production cross-sections. The spectroscopic study of very neutron-rich nuclei is very dependent of these production rates. A study of beta-delayed neutron emission which leads to new measurements of half-lives and neutron delayed emission probabilities is achieved with a liquid scintillator detector. The results which are then compared to different theories are of interest for the understanding of natural production of heavy elements (r processus) [fr

  17. Neutron-rich isotopes around the r-process 'waiting-point' nuclei 2979Cu50 and 3080Zn50

    International Nuclear Information System (INIS)

    Kratz, K.L.; Gabelmann, H.; Pfeiffer, B.; Woehr, A.

    1991-01-01

    Beta-decay half-lives (T 1/2 ) and delayed-neutron emission probabilities (P n ) of very neutron-rich Cu to As nuclei have been measured, among them the new isotopes 77 Cu 48 , 79 Cu 50 , 81 Zn 51 and 84 Ga 53 . With the T 1/2 and P n -values of now four N≅50 'waiting-point' nuclei known, our hypothesis that the r-process has attained a local β-flow equilibrium around A≅80 is further strengthened. (orig.)

  18. Anisotropy of favoured alpha transitions producing even-even deformed nuclei

    International Nuclear Information System (INIS)

    Tavares, O.A.P.

    1997-05-01

    The anisotropy in favoured alpha transitions which produce even-even deformed nuclei is discussed. A simple, Gamow's-like model which takes into account the quadrupole deformation of the product nucleus has been formulated to calculate the alpha decay half-life. It is assumed that before tunneling into a purely Coulomb potential barrier the two-body system oscillated isotropically, thus giving rise to an equivalent, average preferential polar direction θ 0 (referred to the symmetry axis of the ellipsoidal shape of the product nucleus) for alpha emission in favoured alpha transitions of even-even nuclei. (author)

  19. Nuclear spectroscopy of very proton rich nuclei through HI induced reactions; the 14s high spin isomer in /sup 95/Pd

    CERN Document Server

    Nolte, E; Geier, R; Gui, S Z; Heim, U; Hick, H; Komninos, P; Korschinek, G; Kubik, P; Morinaga, H; Schollmeier, W

    1981-01-01

    /sup 40/Ca, /sup 58/Ni and /sup 60/Ni beams from the Munich tandem and the Munich heavy ion postaccelerator have been used to produce very proton rich nuclei in the N=50 N=82 regions. The residual nuclei have been studied with the help of gamma and particle spectroscopy. The level schemes of /sup 95/Rh, /sup 146/Dy and /sup 150/Er and the beta -decay schemes, /sup 95/Pd/sup m/ to /sup 95/Rh, /sup 144/Tb to /sup 144/Gd, /sup 146/Ho to /sup 146/Dy to /sup 146/Tb to /sup 146/Gd, /sup 148/Er to /sup 148/Ho to /sup 148/Dy and /sup 150/Tm to /sup 150/Er to /sup 150/Dy have been investigated. beta delayed proton emission from a J/sup pi / approximately=21/sup +/ isomeric state in /sup 95/Pd has been observed. (12 refs).

  20. Production of n-rich Nuclei along the Closed Shell N=126 in the collision 136Xe + 208Pb @E lab =870 MeV

    Science.gov (United States)

    Quero, D.; Vardaci, E.; Kozulin, E. M.; Zagrebaev, V. A.; Corradi, L.; Pulcini, A.; La Rana, G.; Itkis, I. M.; Knyazheva, G. N.; Novikov, K.; Harca, I.; Fioretto, E.; Stefanini, A. M.; Montanari, D.; Montagnoli, G.; Scarlassara, F.; Szilner, S.; Mijatović, T.; Trzaska, W. H.

    2018-05-01

    Multi-nucleon transfer reactions are nowadays the only known mean to produce neutron-rich nuclei in the Terra Incognita. The closed-shell region N=126 is crucial for both studying shell-quenching in exotic nuclei and the r-process, being its last “waiting-point”. The choice of suitable reactions is challenging and a favorable case is 136Xe+208Pb, near the Coulomb barrier, because their neutron shell-closures play a stabilizing role, favoring the proton-transfer from lead to xenon. TOF-TOF data were analyzed to reconstruct the mass-energy distribution of the primary fragments. Preliminary results of an experiment held at Laboratori Nazionali di Legnaro with PRISMA, aimed at A and Z identification of the products, will be shown.

  1. Mass measurement project by determination of Q{sub {beta}} for neutron-rich nuclei; Projet de mesure des masses par determination des Q{sub {beta}} pour des noyaux tres riches en neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Pautrat, M; Lagrange, J M; Petizon, L [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Vanhorenbeeck, J; Duhamel, P [Brussels Univ. (Belgium). Inst. d` Astronomie et d` Astrophysique; Binon, F [Universite Libre de Bruxelles (Belgium)

    1994-12-31

    The aim of the project described hereafter is to collect new data on the exotic neutron rich nuclei of the Fe to Zn region, and in particular to determine their masses, for both nuclear physics and astrophysics purposes. These isotopes will be produced through projectile fragmentation at the GANIL facility and selected by the LISE3 spectrometer. Their half-lives will be measured as well as the energy of their main {gamma} rays; {gamma} - {gamma} coincidences will then allow to build a preliminary level scheme. The analysis of {beta} spectra and {beta} - {gamma} coincidences will finally provide the maximum {beta} decay energies of the studied nuclei leading to their masses. The difficulties arising from the low production rates, the {beta} detection, the data handling are discussed together with the solutions proposed to overcome them. (authors). 17 refs.

  2. Mass-measurements far from stability of neutron rich light nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Gregoire, C.; Schutz, Y.

    1987-07-01

    The study of nuclei far from stability is a verification of nuclear models that generally have been established using the properties of stable nuclei. The direct measurement of the mass has considerable advantages for nuclei very far from stability. This implies a high resolution measurement device, reasonable production rates of the nuclei of interest, and very low systematic errors. This is discussed here. Some of the results have been published recently. They are compared to different classes of models. Region presented is Z=9-15 region

  3. Covariant description of shape evolution and shape coexistence in neutron-rich nuclei at N≈60

    International Nuclear Information System (INIS)

    Xiang, J.; Li, Z.P.; Li, Z.X.; Yao, J.M.; Meng, J.

    2012-01-01

    The shape evolution and shape coexistence phenomena in neutron-rich nuclei at N≈60, including Kr, Sr, Zr, and Mo isotopes, are studied in the covariant density functional theory (DFT) with the new parameter set PC-PK1. Pairing correlations are treated using the BCS approximation with a separable pairing force. Sharp rising in the charge radii of Sr and Zr isotopes at N=60 is observed and shown to be related to the rapid changing in nuclear shapes. The shape evolution is moderate in neighboring Kr and Mo isotopes. Similar as the results of previous Hartree–Fock–Bogoliubov (HFB) calculations with the Gogny force, triaxiality is observed in Mo isotopes and shown to be essential to reproduce quantitatively the corresponding charge radii. In addition, the coexistence of prolate and oblate shapes is found in both 98 Sr and 100 Zr. The observed oblate and prolate minima are related to the low single-particle energy level density around the Fermi surfaces of neutron and proton respectively. Furthermore, the 5-dimensional (5D) collective Hamiltonian determined by the calculations of the PC-PK1 energy functional is solved for 98 Sr and 100 Zr. The resultant excitation energy of 0 2 + state and E0 transition strength ρ 2 (E0;0 2 + →0 1 + ) are in rather good agreement with the data. It is found that the lower barrier height separating the two competing minima along the γ deformation in 100 Zr gives rise to the larger ρ 2 (E0;0 2 + →0 1 + ) than that in 98 Sr.

  4. Alpha decay and cluster decay of some neutron-rich actinide nuclei

    Indian Academy of Sciences (India)

    2017-02-09

    Feb 9, 2017 ... Abstract. Nuclei in the actinide region are good in exhibiting cluster radioactivity. In the present work, the half-lives of α-decay and heavy cluster emission from certain actinide nuclei have been calculated using cubic plus Yukawa plus exponential model (CYEM). Our model has a cubic potential for the ...

  5. Synthesis of neutron-rich transuranic nuclei in fissile spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Mishustin, Igor, E-mail: mishustin@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); “Kurchatov Institute”, National Research Center, 123182 Moscow (Russian Federation); Malyshkin, Yury, E-mail: malyshkin@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Pshenichnov, Igor, E-mail: pshenich@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Greiner, Walter [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany)

    2015-04-15

    A possibility of synthesizing neutron-rich superheavy elements in spallation targets of Accelerator Driven Systems (ADS) is considered. A dedicated software called Nuclide Composition Dynamics (NuCoD) was developed to model the evolution of isotope composition in the targets during a long-time irradiation by intense proton and deuteron beams. Simulation results show that transuranic elements up to {sup 249}Bk can be produced in multiple neutron capture reactions in macroscopic quantities. However, the neutron flux achievable in a spallation target is still insufficient to overcome the so-called fermium gap. Further optimization of the target design, in particular, by including moderating material and covering it by a reflector could turn ADS into an alternative source of transuranic elements in addition to nuclear fission reactors.

  6. β-delayed p-decay of proton-rich nuclei ^23Al and ^31Cl and explosive H-burning in novae

    Science.gov (United States)

    Trache, L.; Banu, A.; Hardy, J. C.; McCleskey, M.; Simmons, E.; Tabacaru, G.; Tribble, R. E.; Aysto, J.; Jokinen, A.; Saastamoinen, A.; Davinson, T.; Woods, P. J.; Achouri, L.; Roeder, B.

    2008-10-01

    We developed a technique to measure β-delayed proton-decay of proton-rich nuclei produced and separated with MARS at TAMU. In particular, we studied the decay of ^23Al and ^31Cl, both important for understanding explosive H-burning in novae. We have pulsed the beam, implanting the source nuclei moving at about 40 MeV/u in a thin Si strip detector, and then measured β-p and β-γ coincidences simultaneously. The states populated above the proton threshold in ^23Mg and ^31S, respectively, may proton decay. They are resonances in the reaction ^22Na(p,γ)^23Mg (crucial for the depletion of ^22Na in ONe novae) and in ^30P(p,γ)^31S (critical point in explosive H-burning in novae), but the protons emitted have very low energies, starting at about 200 keV, an experimental challenge. The setup and the results are described. The β-decay schemes were established for both nuclei, and IAS identified. The technique has shown a remarkable selectivity to β-delayed charged particle emission and shown to work even at radioactive beam rates of a few pps, for rare isotopes with lifetimes as low as 10s msec.

  7. Nuclear shell effects in neutron-rich nuclei around N=20 and N=32,34

    International Nuclear Information System (INIS)

    Seidlitz, Michael

    2012-01-01

    Nuclear shell effects in neutron-rich nuclei around N=20 and N=32,34 were studied by means of reduced transition probabilities, i.e. B(E2) and B(M1) values. To this end a series of Coulomb-excitation experiments, employing radioactive 31 Mg and 29,30 Na beams, as well as a precise lifetime experiment of excited states in 56 Cr were performed. The collective properties of excited states of 31 Mg were the subject of a Coulomb-excitation experiment at REX-ISOLDE, CERN, employing a radioactive 31 Mg beam at a beam energy of 3.0 MeV/u. The beam intensity amounted to 3000 ions/s on average. The highly efficient MINIBALL setup was employed, consisting of eight HPGe cluster detectors for γ-ray detection and a segmented Si-detector for coincident particle detection. The level scheme of 31 Mg was extended. Spin and parity assignment of the observed 945 keV state yielded 5/2 + and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of 30,31,32 Mg establishes that for the N=19 magnesium isotope not only the ground state but also excited states are largely dominated by a deformed pf intruder configuration. This implies that 31 Mg is part of the so-called ''island of inversion''. Coulomb-excitation experiments of radioactive 29,30 Na were carried out at REX-ISOLDE, CERN, at a final beam energy of 2.85 MeV/u. De-excitation γ rays were detected by the MINIBALL γ-ray spectrometer in coincidence with scattered particles in a segmented Si-detector. Despite rather low beam intensities transition probabilities to the first excited states were deduced. Results of very recently published experiments at MSU and TRIUMF could be largely confirmed and extended. The measured B(E2) values agree well with shell-model predictions, supporting the idea that in the sodium isotopic chain the ground-state wave function contains a significant intruder admixture already at N=18, with N=19 having an almost pure 2p2h deformed ground

  8. Study of some continuous spectra produced by nuclear reactions with light nuclei

    International Nuclear Information System (INIS)

    Marquez, L.

    1966-01-01

    The continuous spectra coming from several nuclear reactions with light nuclei were measured. The spectra can be explained by a two-step reaction mechanism; however, the reactions produced by 6 Li are different. A mechanism was proposed to explain their spectra based on the following assumptions: 6 Li makes a nuclear molecule with the target which subsequently breaks up in such a way that an α particle comes out with the kinetic energy that it has in the molecule. The calculated spectra and those measured are in good agreement. (author) [fr

  9. Nuclear symmetry energy and the neutron skin in neutron-rich nuclei

    NARCIS (Netherlands)

    Dieperink, AEL; Dewulf, Y; Van Neck, D; Waroquier, M; Rodin, [No Value

    2003-01-01

    The symmetry energy for nuclear matter and its relation to the neutron. skin in finite nuclei is discussed. The symmetry energy as a function of density obtained in a self-consistent Green function approach is presented and compared to the results of other recent theoretical approaches. A partial

  10. Exploratory analysis of a neutron-rich nuclei source based on photo-fission

    CERN Document Server

    Mirea, M; Clapier, F; Essabaa, S; Groza, L; Ibrahim, F; Kandri-Rody, S; Müller, A C; Pauwels, N; Proust, J

    2003-01-01

    A source of neutron rich ions can be conceived through the photo-fission process. An exploratory study of such a source is realized. A survey of the radiative electron energy loss theory is reported in order to estimate numerically the bremsstrahlung production of thick targets. The resulted bremsstrahlung angular and energy theoretical distributions delivered from W and UCx thick converters are presented and compared with previous results. Some quantities as the number of fission events produced in the fissionable source and the energy loss in the converters are also reported as function of the geometry of the combination and the incident electron energy. An attempt of comparison with experimental data shows a quantitative agreement. This study is focussed on initial kinetic energies of the electron beam included in the range 30-60 MeV, suitable for the production of large radiative gamma-ray yields able to induce the $^{238}$U fission through the giant dipole resonance. A confrontation with the number of fi...

  11. Structure of neutron rich nuclei of Germanium and Gallium beyond N equals 50 at Alto

    International Nuclear Information System (INIS)

    Lebois, M.

    2008-09-01

    The gamma rays following the beta decay of the following very neutron-rich isotopes: 82,83,84 Ga produced by photo-fission, have been studied at the newly built ISOL facility in Orsay: ALTO. In ALTO the interaction of an electron beam with U 238 target generates a continuous spectra of Bremsstrahlung gamma radiation that triggers U 238 fission. The fission fragments are then ionized, extracted and mass-separated. The analysis of the data has shown the existence of an isomer in 31 84 Ga 53 and has enabled us to confirm known results on 32 83 Ge 51 energy levels including the gamma transition between the 1/2+ state at 247,7 KeV and the fundamental state. We have also proposed the first energy level scheme for 33 84 As 51 . In order to understand the structure of the nucleus we have used the Thankappan and True model that gives a description of the coupling between the pair-pair core (half-magical) and the single nucleon. This model applied to the N=51 chain ( 38 89 Sr 51 , 36 87 Kr 51 , 34 85 Se 51 , 32 83 Ge 51 and 30 81 Zn 51 ) has allowed us to see the main features of odd isotope structure. We have also confirmed previous results concerning the nature of the states in the following decay 31 83 Ga 52 → 32 83 Ge 51

  12. Process for producing uranium oxide rich compositions from uranium hexafluoride

    International Nuclear Information System (INIS)

    DeHollander, W.R.; Fenimore, C.P.

    1978-01-01

    Conversion of gaseous uranium hexafluoride to a uranium dioxide rich composition in the presence of an active flame in a reactor defining a reaction zone is achieved by separately introducing a first gaseous reactant comprising a mixture of uranium hexafluoride and a reducing carrier gas, and a second gaseous reactant comprising an oxygen-containing gas. The reactants are separated by a shielding gas as they are introduced to the reaction zone. The shielding gas temporarily separates the gaseous reactants and temporarily prevents substantial mixing and reacting of the gaseous reactants. The flame occurring in the reaction zone is maintained away from contact with the inlet introducing the mixture to the reaction zone. After suitable treatment, the uranium dioxide rich composition is capable of being fabricated into bodies of desired configuration for loading into nuclear fuel rods. Alternatively, an oxygen-containing gas as a third gaseous reactant is introduced when the uranium hexafluoride conversion to the uranium dioxide rich composition is substantially complete. This results in oxidizing the uranium dioxide rich composition to a higher oxide of uranium with conversion of any residual reducing gas to its oxidized form

  13. Superheavy nuclei and quasi-atoms produced in collisions of transuranium ions

    International Nuclear Information System (INIS)

    Zagrebaev, V.; Oganessian, Y.; Itkis, M.; Greiner, W.

    2005-01-01

    , may remain in contact rather long time. This time delay (up to 10 -19 s) could significantly increase the yield of the so-called spontaneous positron emission from super-strong electric field of quasi-atoms by a static QED process (transition from neutral to charged QED vacuum). This effect was searched sometime ago at GSI but no clear evidences of it have been found. New experiments may be performed now based on our new knowledge of collision dynamics of these nuclei. About twenty years ago damped collisions of very heavy nuclei have been used also for production of chemically separated long-lived actinides. The cross sections were found to be exponentially decreasing with increase of a charge number of heavier fragment, up to the level of 0.1 μb for production of Md isotopes in U + Cm collisions. A new effect, which we found here, is the 'inverse quasi-fission' process. In this process a superheavy nuclear system, say Th + Cf, travelling over the multidimensional potential energy surface, changes its mass asymmetry and may fall into the so-called lead valley. If Th comes to Pb, then Cf grows to the element 106. In spite of rather high excitation energy and low survival probability of residual fragments, this effect significantly increases the yield of nuclei complementary to lead and give us a new way for production of neutron rich (more close to the island of stability) superheavy elements in addition to the extensively used complete fusion reactions. These and some other prospects of subsequent theoretical and experimental studies along with possible collaborations in the field will be discussed in the talk

  14. Investigations of charge-changing processes for light proton-rich nuclei on carbon and solid-hydrogen targets

    Energy Technology Data Exchange (ETDEWEB)

    Sawahata, K. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Ozawa, A., E-mail: ozawa@tac.tsukuba.ac.jp [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Saito, Y.; Abe, Y.; Ichikawa, Y.; Inaba, N.; Ishibashi, Y. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Kitagawa, A. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Matsunaga, S. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Moriguchi, T.; Nagae, D.; Okada, S. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Sato, S. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Suzuki, S. [Institute of Physics, University of Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T.; Takeuchi, Y.; Yamaguchi, T. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Zenihiro, J. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)

    2017-05-15

    We investigated charge-changing processes (total charge-changing cross sections and partial charge-changing cross sections) for light proton-rich nuclei ({sup 34–36}Ar, {sup 33}Cl, {sup 25–28}Si) at around 300A MeV on carbon and solid-hydrogen targets. We estimated the nuclear proton point radii of {sup 33}Cl and {sup 25,26,27}Si from the observed total charge-changing cross sections by using Glauber-model calculations with a phenomenological correction factor. Furthermore, we estimated the proton skin thickness for {sup 33}Cl coupled with its previously observed matter radius. From investigations of the partial charge-changing cross sections, clear zigzag pattern was observed for all isotopes. The present studies suggest that the pattern may be common in the proton-rich side, and depends on the odd–even nature of the fragment charge.

  15. Effects of momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei

    International Nuclear Information System (INIS)

    Li Baoan; Das, Champak B.; Das Gupta, Subal; Gale, Charles

    2004-01-01

    Using an isospin- and momentum-dependent transport model we study effects of the momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy E sym (ρ) lead to significantly different predictions on several E sym (ρ)-sensitive experimental observables especially for energetic nucleons. The momentum- and density-dependence of the symmetry potential have to be determined simultaneously in order to extract the E sym (ρ) accurately. The isospin asymmetry of midrapidity nucleons at high transverse momenta is particularly sensitive to the momentum-dependence of the symmetry potential. It is thus very useful for investigating accurately the equation of state of dense neutron-rich matter

  16. Antinociception induced by stimulating amygdaloid nuclei in rats: changes produced by systemically administered antagonists

    Directory of Open Access Journals (Sweden)

    M.A. Oliveira

    1998-05-01

    Full Text Available The antinociceptive effects of stimulating the medial (ME and central (CE nuclei of the amygdala in rats were evaluated by the changes in the latency for the tail withdrawal reflex to noxious heating of the skin. A 30-s period of sine-wave stimulation of the ME or CE produced a significant and short increase in the duration of tail flick latency. A 15-s period of stimulation was ineffective. Repeated stimulation of these nuclei at 48-h intervals produced progressively smaller effects. The antinociception evoked from the ME was significantly reduced by the previous systemic administration of naloxone, methysergide, atropine, phenoxybenzamine, and propranolol, but not by mecamylamine, all given at the dose of 1.0 mg/kg. Previous systemic administration of naloxone, atropine, and propranolol, but not methysergide, phenoxybenzamine, or mecamylamine, was effective against the effects of stimulating the CE. We conclude that the antinociceptive effects of stimulating the ME involve at least opioid, serotonergic, adrenergic, and muscarinic cholinergic descending mechanisms. The effects of stimulating the CE involve at least opioid, ß-adrenergic, and muscarinic cholinergic descending mechanisms.

  17. Investigation of correlations in light neutron-rich nuclei; Etude des correlations dans les noyaux legers riches en neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Normand, G

    2004-10-01

    Correlations play a crucial role in understanding the structure of light nuclei at and beyond the neutron drip-line. In this context, the two-neutron halo nucleus He{sup 6} and the unbound systems H{sup 5}, He{sup 7,9} and Li{sup 10} have been studied via measurements of the breakup of beams of He{sup 6} and Be{sup 11,12}. The CHARISSA and DEMON detector arrays were employed. The interpretation was facilitated by a simulation code (SILLAGE) which provided for the setup. In the case of He{sup 7}, the existence of an excited state with E{sub r} {approx} 1 MeV and gamma {approx} 0.75 MeV was confirmed. The virtual character of the s-wave ground state of Li{sup 10} was also confirmed and a scattering length of as {approx} -16 fm deduced. The results obtained for He{sup 9} suggest that a virtual s-wave state may exist just above threshold. The study of the three-body breakup of He{sup 6} found that the decay of the first 2+ state is essentially direct, while the decay of the remaining continuum strength is sequential - passage via He{sup 5}. Using the technique of intensity interferometry an rms separation between the halo neutrons of 7.7 +- 0.8 fm was derived. This result was confirmed by a complementary method utilizing Dalitz plots. In the case of H{sup 5}, the invariant mass spectrum was found to exhibit a broad (gamma {approx} 2 MeV) structure some 1.8 MeV above threshold. Comparison with recent three-body model calculations suggest that this corresponds to the predicted 1/2+ ground state. An rms valence neutron separation of some 5.5 fm was estimated. A search was also carried out for the 4n system using the Be{sup 12*} (2 alpha + Xn decay channel). No signal was observed beyond that expected on the basis of the known background processes. (author)

  18. Search for the neutron-rich nuclei in RIKEN-RIPS

    Energy Technology Data Exchange (ETDEWEB)

    Notani, Masahiro; Aoi, Nori; Fukuda, Naoki [Tokyo Univ. (Japan). Dept. of Physics] [and others

    1997-05-01

    {sup 64}Ni and {sup 181}Ta target were irradiated with {sup 48}Ca beam (70 AMeV) by R201N experiment in this paper. The production cross sections and yields of F, Ne, Na and Al isotopes were determined by particle identification of RIPS. New three nuclei, {sup 38}Mg and {sup 40},{sup 41}Al were found. Moreover, unstable nuclear isomer {sup 32m}Al was studied by measuring {gamma}-ray emission energy spectrum. The life and rate of isomer were determined. The rate of isomer was different from that of other systems. (S.Y.)

  19. Detection of the weak γ activities from new neutron-rich nuclei

    International Nuclear Information System (INIS)

    Zhang Li; Wang Jicheng; Zhao Jinhua; Yang Yongfeng; Zheng Jiwen; Hu Qingyuan; Guo Tianrui

    2003-01-01

    Energic signals of γ rays detected by a HPGe γ detector were coincided with γ-ray, energy-loss signals detected by a 4πΔEβ detector. Then the coinciding β-ray spectra was anticoincided with timing logical signals of 511 keV γ ray created in positron annihilate, detected by a large BGO detector. This special coincidence-anticoincidence system has played an important role in the first observation of the new neutron-rich nuclide 209 Hg. It is shown that this is an effective method to detecting very weak γ-ray activities of neutron-rich isotope in an element-separation sample

  20. Beta spectroscopy on neutron-rich nuclei of mass 93<=A<=100

    International Nuclear Information System (INIS)

    Pahlmann, B.

    1982-01-01

    In the present thesis for the first time measurements of the Qsub(β) value of the neutron-rich fission products sup(99,100)Sr and 99 Rb were performed. Preliminary results could be obtained on the beta decays of the nuclides 100 Rb and 100 Y. (orig./HSI) [de

  1. Neutron-proton pairing effect on the proton-rich nuclei moment of inertia

    International Nuclear Information System (INIS)

    Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H.; Fellah, M.; Allal, N.H.

    2008-01-01

    The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 ≤ A ≤ 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)

  2. Neutron-proton pairing effect on the proton-rich nuclei moment of inertia

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H. [Laboratoire de Physique Theorique, Faculte de Physique, USTHB, Algiers (Algeria); Fellah, M.; Allal, N.H. [Centre de Recherche Nucleaire d' Alger, COMENA, Algiers (Algeria)

    2008-07-01

    The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 {<=} A {<=} 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)

  3. Electric quadrupole moments of neutron-rich nuclei {sup 32}Al and {sup 31}Al

    Energy Technology Data Exchange (ETDEWEB)

    Kameda, D., E-mail: kameda@ribf.riken.jp; Ueno, H. [RIKEN Nishina Center (Japan); Asahi, K.; Nagae, D.; Takemura, M.; Shimada, K. [Tokyo Institute of Technology, Department of Physics (Japan); Yoshimi, A.; Nagatomo, T.; Sugimoto, T. [RIKEN Nishina Center (Japan); Uchida, M.; Arai, T.; Takase, K.; Suda, S.; Inoue, T. [Tokyo Institute of Technology, Department of Physics (Japan); Murata, J.; Kawamura, H. [Rikkyo University, Department of Physics (Japan); Watanabe, H. [Australian National University, Department of Nuclear Physics (Australia); Kobayashi, Y.; Ishihara, M. [RIKEN Nishina Center (Japan)

    2007-11-15

    The electric quadrupole moments for the ground states of {sup 32}Al and {sup 31}Al have been measured by the {beta} ray-detected nuclear quadrupole resonance method. Spin-polarized {sup 32}Al and {sup 31}Al nuclei were obtained from the fragmentation of {sup 40}Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal {alpha}-Al{sub 2}O{sub 3} stopper. The measured Q moment of {sup 32}Al, |Q({sup 32}Al)| = 24(2) mb, is in good agreement with a conventional shell-model calculation with a full sd model space and empirical effective charges, while that of {sup 31}Al is considerably smaller than the sd calculations.

  4. Microscopic description of quadrupole collectivity in neutron-rich nuclei across the N = 126 shell closure

    Science.gov (United States)

    Rodríguez-Guzmán, R.; Robledo, L. M.; Sharma, M. M.

    2015-06-01

    The quadrupole collectivity in Nd, Sm, Gd, Dy, Er, Yb, Hf and W nuclei with neutron numbers 122 ≤ N ≤ 156 is studied, both at the mean field level and beyond, using the Gogny energy density functional. Besides the robustness of the N = 126 neutron shell closure, it is shown that the onset of static deformations in those isotopic chains with increasing neutron number leads to an enhanced stability and further extends the corresponding two-neutron drip lines far beyond what could be expected from spherical calculations. Independence of the mean-field predictions with respect to the particular version of the Gogny energy density functional employed is demonstrated by comparing results based on the D1S and D1M parameter sets. Correlations beyond mean field are taken into account in the framework of the angular momentum projected generator coordinate method calculation. It is shown that N = 126 remains a robust neutron magic number when dynamical effects are included. The analysis of the collective wave functions, average deformations and excitation energies indicate that, with increasing neutron number, the zero-point quantum corrections lead to dominant prolate configurations in the 0{1/+}, 0{2/+}, 2{1/+} and 2{2/+} states of the studied nuclei. Moreover, those dynamical deformation effects provide an enhanced stability that further supports the mean-field predictions, corroborating a shift of the r-process path to higher neutron numbers. Beyond mean-field calculations provide a smaller shell gap at N = 126 than the mean-field one in good agreement with previous theoretical studies. However, the shell gap still remains strong enough in the two-neutron drip lines.

  5. Direct mass and lifetime measurements of neutron-rich nuclei up to A∼100 using the TOFI spectrometer at LAMPF

    International Nuclear Information System (INIS)

    Lind, V.G.

    1993-01-01

    This project was directed toward the study of neutron-rich nuclei using the experimental facilities at LAMPF, which is a part of LANL. The principal results of the investigation include the discovery of many new isotopes along with a measurement of their masses and in particular those nuclides in the Z = 7--19 and 14 --26 regions of the chart of the nuclides.Thirty-four new nuclides were detected and studied with their masses being measured with relatively high accuracy, and an additional twenty-six that were previously known and measured were remeasured to an improved accuracy. Besides providing new information about the mass surface in new and extended redons of the chart of the nuclides, this investigation enabled properties and previously unknown structure of some of the nuclei to be determined such as nuclear deformation among some of the nuclides. Also a study of the neutron pairing gaps and the proton pairing gaps among these nuclides was made. Other developments also achieved included instrument (TOFI) improvements and upgrades and theoretical investigations into the masses of the hadrons

  6. The structure of neutron-rich nuclei explored via in-beam gamma-ray spectroscopy of fast beams

    International Nuclear Information System (INIS)

    Glasmacher, T.; Campbell, C.M.; Church, J.A.; Dinca, D.C.; Hansen, P.G.; Olliver, H.; Perry, B.C.; Sherrill, B.M.; Terry, J.R.; Bazin, D.; Enders, J.; Gade, A.; Hu, Z.; Mueller, W.F.

    2003-01-01

    In-beam gamma-ray spectroscopy with fast exotic beams provides an efficient tool to study bound states in exotic neutron-rich nuclei. Specialized experimental techniques have been developed and explore different aspects of nuclear structure. Inelastic scattering experiments with γ-ray detection can measure the response of exotic nuclei to electromagnetic (Coulomb excitation with a heavy target) or hadronic probes (proton scattering with hydrogen target). In-beam fragmentation populates higher-lying bound states to establish levels. Single- and two-nucleon knockout reactions allow for detailed wavefunction spectroscopy of individual levels and for the measurement of spectroscopic factors. Experimental programs employing these techniques are now underway at all projectile-fragmentation facilities around the world. Here we report on several successful in-beam gamma-ray spectroscopy experiments that have been performed at the Coupled Cyclotron Facility at Michigan State University with an emphasis on elucidating the evolution of nuclear structure around neutron numbers N=16, N=20, and N=28 in the π(sd) shell. (orig.)

  7. Dipole resonances in light neutron-rich nuclei studied with time-dependent calculations of antisymmetrized molecular dynamics

    International Nuclear Information System (INIS)

    Kanada-En'yo, Y.; Kimura, M.

    2005-01-01

    To study isovector dipole responses of neutron-rich nuclei, we applied a time-dependent method of antisymmetrized molecular dynamics. The dipole resonances in Be, B, and C isotopes were investigated. In 10 Be, 15 B, and 16 C, collective modes of the vibration between a core and valence neutrons cause soft resonances at the excitation energy E x =10-15 MeV below the giant dipole resonance (GDR). In 16 C, we found that a remarkable peak at E x =14 MeV corresponds to the coherent motion of four valence neutrons against a 12 C core, whereas the GDR arises in the E x >20 MeV region because of vibration within the core. In 17 B and 18 C, the dipole strengths in the low-energy region decline compared with those in 15 B and 16 C. We also discuss the energy-weighted sum rule for the E1 transitions

  8. Projected shell model study of odd-odd f-p-g shell proton-rich nuclei

    International Nuclear Information System (INIS)

    Palit, R.; Sheikh, J.A.; Sun, Y.; Jain, H.C.

    2003-01-01

    A systematic study of two-quasiparticle bands of the proton-rich odd-odd nuclei in the mass A∼70-80 region is performed using the projected shell model approach. The study includes Br, Rb, and Y isotopes with N=Z+2 and Z+4. We describe the energy spectra and electromagnetic transition strengths in terms of the configuration mixing of the angular-momentum projected multi-quasiparticle states. Signature splitting and signature inversion in the rotational bands are discussed and are shown to be well described. A preliminary study of the odd-odd N=Z nucleus 74 Rb, using the concept of spontaneous symmetry breaking is also presented

  9. Estimates of fission barrier heights for neutron-deficient Po to Ra nuclei produced in fusion reactions

    Directory of Open Access Journals (Sweden)

    Sagaidak Roman

    2017-01-01

    Full Text Available The cross section data for fission and evaporation residue production in fusion reactions leading to nuclei from Po to Ra have been considered in a systematic way in the framework of the conventional barrier-passing (fusion model coupled with the statistical model. The cross section data obtained in very asymmetric projectile-target combinations can be described within these models rather well with the adjusted model parameters. In particular, one can scale and fix the macroscopic (liquid-drop fission barrier heights (FBHs for nuclei involved in the de-excitation of compound nuclei produced in the reactions. The macroscopic FBHs for nuclei from Po to Ra have been derived in the framework of such analysis and compared with the predictions of various theoretical models.

  10. {gamma} ray spectroscopy of neutron rich nuclei around N=20; Spectroscopie {gamma} des noyaux riches en neutrons autour de N=20

    Energy Technology Data Exchange (ETDEWEB)

    Gelin, M

    2007-09-15

    There is an island of inversion around {sup 32}Mg (12 protons, 20 neutrons) in contradiction with a shell closure N=20. It means a coexistence of spherical and deformed shapes. This work is devoted to the study of {gamma}-ray spectroscopy for nuclei in this region, based on an experiment done at GANIL with a composite secondary beam produced by fragmentation. The originality of the method used here lies in the possibility to study simultaneously several nuclei, and for each of them to explore several reaction channels. The VAMOS spectrometer was used for the identification of the ejectiles. The {gamma}-rays were detected with EXOGAM, a germanium clover array. The detectors used before and after the target allowed for a unique identification and a selection of the reaction channel: inelastic scattering, transfer and fragmentation reaction. In this thesis the following nuclei were studied: {sup 28}Ne, {sup 30-32}Mg {sup 31-34}Al, {sup 33-35}Si, {sup 35}P. New {gamma}-rays have been observed. The {gamma}-ray angular distributions and {gamma}-{gamma} angular correlations have been measured for some transitions. Assignment of spins and parities has been proposed for some states. In particular, in {sup 34}Si, the 3{sup -} assignment is confirmed and a new candidate for the second 0{sup +} has been proposed. In {sup 32}Mg, the state at 2.321 MeV, for which conflicting assignment existed, is deduced from the present data as a 4{sup +}, and a 6{sup +} state is proposed. (author)

  11. Particle-number conservation in odd mass proton-rich nuclei in the isovector pairing case

    International Nuclear Information System (INIS)

    Fellah, M.; Allal, N.H.; Oudih, M.R.

    2015-01-01

    An expression of a wave function which describes odd–even systems in the isovector pairing case is proposed within the BCS approach. It is shown that it correctly generalizes the one used in the pairing between like-particles case. It is then projected on the good proton and neutron numbers using the Sharp-BCS (SBCS) method. The expressions of the expectation values of the particle-number operator and its square, as well as the energy, are deduced in both approaches. The formalism is applied to study the isovector pairing effect and the number projection one on the ground state energy of odd mass N ≈ Z nuclei using the single-particle energies of a deformed Woods–Saxon mean-field. It is shown that both effects on energy do not exceed 2%, however, the absolute deviations may reach several MeV. Moreover, the np pairing effect rapidly diminishes as a function of (N - Z). The deformation effect is also studied. It is shown that the np pairing effect, either before or after the projection, as well as the projection effect, when including or not the isovector pairing, depends upon the deformation. However, it seems that the predicted ground state deformation will remain the same in the four approaches. (author)

  12. $\\beta$-delayed fission in proton-rich nuclei in the lead region

    CERN Document Server

    AUTHOR|(CDS)2085005; Huyse, Mark; Popescu, Lucia

    Nuclear fission is the breakup of an atomic nucleus into two (sometimes three) fragments, thereby releasing a large amount of energy. Soon after its discovery in the late 1930’s, the gross properties of the fission phenomenon were explained by macroscopic nuclear models. Certain features however, such as asymmetric fission-fragment mass distributions in the actinide region, require the inclusion of microscopic effects. This interplay of the microscopic motion of individual nucleons on this macroscopic process is, until today, not yet fully understood. The phenomenon of fission has therefore been of recurring interest for both theoretical and experimental studies. This thesis work focuses on the $\\beta$-delayed fission ($\\beta$DF) process, an excellent tool to study low-energy fission of exotic nuclei, which was discovered in 1966 in the actinide region. In this two-step process, a precursor nucleus first undergoes $\\beta$-decay to an excited level in the daughter nucleus, which may subsequently fission. Rec...

  13. The nesprin-cytoskeleton interface probed directly on single nuclei is a mechanically rich system.

    Science.gov (United States)

    Balikov, Daniel A; Brady, Sonia K; Ko, Ung Hyun; Shin, Jennifer H; de Pereda, Jose M; Sonnenberg, Arnoud; Sung, Hak-Joon; Lang, Matthew J

    2017-09-03

    The cytoskeleton provides structure and plays an important role in cellular function such as migration, resisting compression forces, and transport. The cytoskeleton also reacts to physical cues such as fluid shear stress or extracellular matrix remodeling by reorganizing filament associations, most commonly focal adhesions and cell-cell cadherin junctions. These mechanical stimuli can result in genome-level changes, and the physical connection of the cytoskeleton to the nucleus provides an optimal conduit for signal transduction by interfacing with nuclear envelope proteins, called nesprins, within the LINC (linker of the nucleus to the cytoskeleton) complex. Using single-molecule on single nuclei assays, we report that the interactions between the nucleus and the cytoskeleton, thought to be nesprin-cytoskeleton interactions, are highly sensitive to force magnitude and direction depending on whether cells are historically interfaced with the matrix or with cell aggregates. Application of ∼10-30 pN forces to these nesprin linkages yielded structural transitions, with a base transition size of 5-6 nm, which are speculated to be associated with partial unfoldings of the spectrin domains of the nesprins and/or structural changes of histones within the nucleus.

  14. Shape transitions in neutron rich 110-112Ru nuclei and empirical relations

    International Nuclear Information System (INIS)

    Bihari, Chhail; Singh, Yuvraj; Gupta, K.K.; Varshney, A.K.; Singh, M.; Gupta, D.K.

    2010-01-01

    In the study of even even neutron rich Ru isotopes, the electromagnetic properties of the γ-vibrational bands are well described by a rigid triaxial rotor for lower spin state and by the rotation vibration collective model for the higher spin states. Thus interpretation in further suggested by the observation of nearly identical moment of inertia, the rotational frequency below the first band crossing, between the ground state and the γ-structural bands for both 110 Ru and 112 Ru which conclude a weak pairing, a more likely suitable explanation of observations. In the present work, the soft rotor energy formula is undertaken suggested by Brentano et al. for yrast band, may be employed to calculate the perturbed energies of the anomalous rotational band (γ-band) generated by rotation of the rigid asymmetric atomic nucleus and the two parameter formula (TPF) of Gupta et al.

  15. I. Surface properties of neutron-rich nuclei. II. Pion condensation at finite temperature

    International Nuclear Information System (INIS)

    Kolehmainen, K.A.

    1983-01-01

    In part I, the energy density formalism, the Thomas-Fermi approximation, and Skyrme-type interactions were used to describe the energy density of a semi-infinite slab of neturon-rich nuclear matter at zero temperature. The existence of a drip phase at low proton fractions is allowed in addition to the more dense nuclear phase, and various bulk properties of both phases are found when the system is in equilibrium. The usual definition of the surface energy is extended to apply to the case where drip is present. Assuming a Fermi function type density profile, a constrained variational calculation is performed to determine the neutron and proton surface diffuseness parameters, the thickness of the neutron skin, and the surface energy. Results are obtained for proton fractions reanging from 0.5 (symmetric nuclear matter) to zero (pure neutron matter) for most Skyrme-type interactions in common use. The results are in close agreement with the predictions of the droplet model, as well as with the results of more exact calculations in those cases where the more exact results exist (only for symmetric or nearly symmetric matter in most cases). Significantly different asymmetry dependences for different interactions are found. In part II, several simple but increasingly complex models are used to calculate the threshold for charged pion condensation in neutron-rich nuclear matter at finite temperature. Unlike in mean field theory descriptions of pion condensation, the effects of thermal excitations of the pion field are included. The thermal pion excitations have two important effects: first, to modify the phase diagram qualitatively from that predicted by mean field theory, and second, to make the phase transition to a spatially nonuniform condensed state at finite temperature always first, rather than second, order

  16. Expression of HPV16 E5 produces enlarged nuclei and polyploidy through endoreplication

    International Nuclear Information System (INIS)

    Hu Lulin; Potapova, Tamara A.; Li Shibo; Rankin, Susannah; Gorbsky, Gary J.; Angeletti, Peter C.; Ceresa, Brian P.

    2010-01-01

    Anogenital cancers and head and neck cancers are causally associated with infection by high-risk human papillomavirus (HPV). The mechanism by which high-risk HPVs contribute to oncogenesis is poorly understood. HPV16 encodes three genes (HPV16 E5, E6, and E7) that can transform cells when expressed independently. HPV16 E6 and E7 have well-described roles causing genomic instability and unregulated cell cycle progression. The role of HPV16 E5 in cell transformation remains to be elucidated. Expression of HPV16 E5 results in enlarged, polyploid nuclei that are dependent on the level and duration of HPV16 E5 expression. Live cell imaging data indicate that these changes do not arise from cell-cell fusion or failed cytokinesis. The increase in nuclear size is a continual process that requires DNA synthesis. We conclude that HPV16 E5 produces polyploid cells by endoreplication. These findings provide insight into how HPV16 E5 can contribute to cell transformation.

  17. Search for short-lived particles produced on nuclei with a heavy liquid mini bubble chamber

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to search for short-lived particles produced in hadronic interactions on nuclei with our high resolution heavy liquid mini bubble chamber BIBC, aiming to establish the cross-section for associated production in hadron-nucleus collisions, its $A$-dependence and an approximate value of the lifetime. The chamber will be operated at a bubble density of 290 bubbles/cm and with an apparent bubble size of 30 $\\mu$m in real space. In test runs at CERN we measured detection efficiencies which, together with simulations of $D\\bar{D}$ production and decay, lead to a sensitivity of 0.25 events/($\\mu$b/N) per day if the lifetime is of the order of $5\\times10^{-13}$s. A null result after 10 days running time would set an upper limit on the production cross section to $3 \\mu$b. \\\\ \\\\ In order to measure the momenta of charged decay products of short-lived particles, the bubble chamber will be placed 1.80 m upstream of the streamer chamber of the NA5 experiment (MPI). The geometrical acceptance ...

  18. Synthesis of neutron-rich transuranic nuclei in fissile spallation targets

    OpenAIRE

    Mishustin, Igor; Malyshkin, Yury; Pshenichnov, Igor; Greiner, Walter

    2014-01-01

    A possibility of synthesizing neutron-reach super-heavy elements in spallation targets of Accelerator Driven Systems (ADS) is considered. A dedicated software called Nuclide Composition Dynamics (NuCoD) was developed to model the evolution of isotope composition in the targets during a long-time irradiation by intense proton and deuteron beams. Simulation results show that transuranic elements up to Bk-249 can be produced in multiple neutron capture reactions in macroscopic quantities. Howeve...

  19. HIGH ENERGY NEUTRINOS PRODUCED IN THE ACCRETION DISKS BY NEUTRONS FROM NUCLEI DISINTEGRATED IN THE AGN JETS

    Energy Technology Data Exchange (ETDEWEB)

    Bednarek, W., E-mail: bednar@uni.lodz.pl [Department of Astrophysics, The University of Lodz, 90-236 Lodz, ul. Pomorska 149/153 (Poland)

    2016-12-20

    We investigate the consequences of acceleration of nuclei in jets of active galaxies not far from the surface of an accretion disk. The nuclei can be accelerated in the re-connection regions in the jet and/or at the jet boundary, between the relativistic jet and its cocoon. It is shown that the relativistic nuclei can efficiently fragment onto specific nucleons in collisions with the disk radiation. Neutrons, directed toward the accretion disk, take a significant part of energy from the relativistic nuclei. These neutrons develop a cascade in the dense accretion disk. We calculate the neutrino spectra produced in such a hadronic cascade within the accretion disk. We propose that the neutrinos produced in such a scenario, from the whole population of super-massive black holes in active galaxies, can explain the extragalactic neutrino background recently measured by the IceCube neutrino detector, provided that a 5% fraction of galaxies have an active galactic nucleus and a few percent of neutrons reach the accretion disk. We predict that the neutrino signals in the present neutrino detectors, produced in terms of such a model, will not be detectable even from the nearby radio galaxies similar to M87.

  20. ZIRCONIUM—HAFNIUM ISOTOPE EVIDENCE FROM METEORITES FOR THE DECOUPLED SYNTHESIS OF LIGHT AND HEAVY NEUTRON-RICH NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Akram, W.; Schönbächler, M. [School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Sprung, P. [Institut für Planetologie, Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Vogel, N. [Institute for Geochemistry and Petrology, ETH, Clausiusstrasse 25, 8092 Zürich (Switzerland)

    2013-11-10

    Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (≤1ε in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (∼2ε). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ≤ 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ☉}) SNII.

  1. Ann Modeling for Grey Particles Produced from Interactions of Different Projectiles with Emulsion Nuclei at 4.5 AGEV/C

    International Nuclear Information System (INIS)

    El-Bakry, M.N.Y.; Basha, A.M.; Rashed, N.; Mahmoud, M.A.; Radi, A.

    2008-01-01

    Artificial Neural Network (ANN) is one of the important tools in high energy physics. In this paper, we are using ANN for modeling the multiplicity distributions of grey particles produced from interactions of P, 3 He, 4 He, 6 Li, 12 C, 24 Mg, and 32 S with emulsion nuclei, light nuclei (CNO), and heavy nuclei (Ag Br). The equations of these distributions were obtained

  2. Coulomb excitation of neutron-rich nuclei between the N=40 and N=50 shell gaps using REX-ISOLDE and the Ge MINIBALL array

    CERN Multimedia

    2002-01-01

    We propose to perform Coulomb excitation experiments of neutron-rich nuclei in the vicinity of $^{68}$Ni towards $^{78}$Ni using the REX-ISOLDE facility coupled with the highly efficient MINIBALL array. Major changes in the structure of the atomic nucleus are expected around the N = 40 subshell closure. Recent B(E2) measurements suggested that $^{68}$Ni behaves like a doubly magic nucleus while neutron-rich Zn isotopes with N>38 exhibit a sudden increase of B(E2) values which may be the signature of deformation. We would like to check and test these predictions for neutron-rich nuclei in the vicinity of N = 40 and N = 50 shell closures like $^{72}$Zn, $^{74}$Zn, $^{76}$Zn, $^{68}$Ni, $^{70}$Ni. Our calculations show that an energy upgrade from 2.2 to 3 MeV/nucleon will be of crucial importance for a part of our study while some nuclei can still be very efficiently studied at an energy of 2.2 MeV/nucleon. Therefore, to perform our experiment in an efficient way, we request 21 shifts of beam time before the ene...

  3. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    Science.gov (United States)

    Oganessian, Yu. Ts.; Shchepunov, V. A.; Dmitriev, S. N.; Itkis, M. G.; Gulbekyan, G. G.; Khabarov, M. V.; Bekhterev, V. V.; Bogomolov, S. L.; Efremov, A. A.; Pashenko, S. V.; Stepantsov, S. V.; Yeremin, A. V.; Yavor, M. I.; Kalimov, A. G.

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3. The set up can work in the wide mass range from A≈20 to A≈500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90° electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  4. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    CERN Document Server

    Oganessian, Yu T; Dmitriev, S N; Itkis, M G; Gulbekyan, G G; Khabarov, M V; Bekhterev, V V; Bogomolov, S L; Efremov, A A; Pashenko, S V; Stepantsov, S V; Yeremin, A V; Yavor, M I; Kalimov, A G

    2003-01-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 sup - sup 3. The set up can work in the wide mass range from A approx 20 to A approx 500, its mass acceptance is as large as +-2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considere...

  5. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    International Nuclear Information System (INIS)

    Oganessian, Yu.Ts.; Shchepunov, V.A.; Dmitriev, S.N.; Itkis, M.G.; Gulbekyan, G.G.; Khabarov, M.V.; Bekhterev, V.V.; Bogomolov, S.L.; Efremov, A.A.; Pashenko, S.V.; Stepantsov, S.V.; Yeremin, A.V.; Yavor, M.I.; Kalimov, A.G.

    2003-01-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10 -3 . The set up can work in the wide mass range from A∼20 to A∼500, its mass acceptance is as large as ±2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given

  6. The project of the mass separator of atomic nuclei produced in heavy ion induced reactions

    Energy Technology Data Exchange (ETDEWEB)

    Oganessian, Yu.Ts.; Shchepunov, V.A. E-mail: shchepun@sunhe.jinr.rushchepun@cv.jinr.ru; Dmitriev, S.N.; Itkis, M.G.; Gulbekyan, G.G.; Khabarov, M.V.; Bekhterev, V.V.; Bogomolov, S.L.; Efremov, A.A.; Pashenko, S.V.; Stepantsov, S.V.; Yeremin, A.V.; Yavor, M.I.; Kalimov, A.G

    2003-05-01

    A new separator and mass analyzer, named MASHA (mass analyzer of super heavy atoms), has been designed at the Flerov Laboratory JINR Dubna to separate and measure masses of nuclei and molecules with precision better than 10{sup -3}. The set up can work in the wide mass range from A{approx}20 to A{approx}500, its mass acceptance is as large as {+-}2.8%. In particular, it allows unambiguous mass identification of super heavy nuclei with a resolution better than 1 amu at the level of 300 amu. Synthesized in nuclear reactions nuclides are emitted from an ECR ion source at energy E=40 kV and charge state Q=+1. Then they pass the following steps of separation and analysis: the first section of rough separation, the second section of separation and mass analysis and the final section of separation with a 90 deg. electrostatic deflector. In the focal plane of the device, a focal plane detector determines positions (masses) of studied nuclei. Ion optics of the analyzer, optimized up to the second order, is considered. Description of its elements and subsystems is given.

  7. Gamma-ray Spectroscopy of Nano-second Isomers in Neutron-rich Ni Region Produced by Deep-inelastic Collisions

    Science.gov (United States)

    Ishii, Tetsuro; Asai, Masato; Kleinheinz, Peter; Matsuda, Makoto; Ichikawa, Shinichi; Makishima, Akiyasu; Ogawa, Masao

    2001-10-01

    We have been studying nuclear structure of neutron-rich nuclei produced by heavy-ion deep-inelastic collisions at the JAERI Tandem Booster facility. In our method using an `isomer-scope', γ-rays only from isomers with T_1/2 > 1ns are measured by shielding Ge detectors from prompt γ rays emitted at the target position. Atomic numbers of isomers can be also identified by detecting projectile-like fragments with Si Δ E-E detectors. Until now, we have found several new isomers in neutron-rich Ni region using about 8 MeV/nucleon ^70Zn, ^76Ge and ^82Se beams and a ^198Pt target of 4.3 mg/cm^2 thickness. In the doubly magic ^68_28Ni_40, the (ν g_9/2^2 ν p_1/2-2)8^+ isomer with T_1/2=23(1) ns was found. In its neighbor nuclei ^69,71Cu, the 19/2^- isomers were found and the energy levels decaying from the isomers can be calculated very accurately by a parameter-free shell model calculation using experimental energy levels as two-body residual interactions. I will also briefly discuss nano-second isomers in ^32,33Si and ^34P produced by 9 MeV/nucleon ^37Cl beams.

  8. $\\gamma$ -spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li

    CERN Multimedia

    We propose an experiment with MINIBALL coupled to T-REX to investigate n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li. The nuclei of interest will be populated by transfer of a triton into $^{94}$Kr, forming the excited $^{97}$Rb nucleus, followed by the emission of an alpha particle, which will be detected in the Si telescopes of T-REX. The $^{97}$Rb product will evaporate 1 or 2 (with the highest probability) neutrons leading to $^{96}$Rb or $^{95}$Rb, respectively. The aim of the experiment is twofold: \\\\ i) to perform a $\\gamma$- spectroscopy study of $^{95,96}$Rb nuclei with N=58,59, the structure of which is of particular interest in investigating the transition towards stable deformation at N=60, \\\\ ii) to acquire experience in using incomplete fusion reactions with the weakly bound $^{7}$Li target, in order to perform, at a later stage with HIE-ISOLDE, similar measurements induced by n-rich radioactive beams of Sn and Hg, for which at least 5 MeV/nucleon are need...

  9. Two genetic loci produce distinct carbohydrate-rich structural components of the Pseudomonas aeruginosa biofilm matrix.

    Science.gov (United States)

    Friedman, Lisa; Kolter, Roberto

    2004-07-01

    Pseudomonas aeruginosa forms biofilms, which are cellular aggregates encased in an extracellular matrix. Molecular genetics studies of three common autoaggregative phenotypes, namely wrinkled colonies, pellicles, and solid-surface-associated biofilms, led to the identification of two loci, pel and psl, that are involved in the production of carbohydrate-rich components of the biofilm matrix. The pel gene cluster is involved in the production of a glucose-rich matrix material in P. aeruginosa strain PA14 (L. Friedman and R. Kolter, Mol. Microbiol. 51:675-690, 2004). Here we investigate the role of the pel gene cluster in P. aeruginosa strain ZK2870 and identify a second genetic locus, termed psl, involved in the production of a mannose-rich matrix material. The 11 predicted protein products of the psl genes are homologous to proteins involved in carbohydrate processing. P. aeruginosa is thus able to produce two distinct carbohydrate-rich matrix materials. Either carbohydrate-rich matrix component appears to be sufficient for mature biofilm formation, and at least one of them is required for mature biofilm formation in P. aeruginosa strains PA14 and ZK2870. Copyright 2004 American Society for Microbiology

  10. Charged particles produced in neutron reactions on nuclei from beryllium to gold

    International Nuclear Information System (INIS)

    Haight, R.C.

    1997-01-01

    Charged-particle production in reactions of neutrons with nuclei has been studied over the past several years with the spallation source of neutrons from 1 to 50 MeV at the Los Alamos Neutron Science Center (LANSCE). Target nuclides include 9Be, C, 27Al, Si, 56Fe, 59Co, 58,60Ni, 93Nb and 197Au. Proton, deuteron, triton, 3He and 4He emission spectra, angular distributions and production cross sections have been measured. Transitions from the compound nuclear reaction mechanism to precompound reactions are clearly seen in the data. The data are compared with data from the literature where available, with evaluated nuclear data libraries, and with calculations where the selection of the nuclear level density prescription is of great importance. Calculations normalized at En = 14 MeV can differ from the present data by a factor of 2 for neutron energies between 5 and 10 MeV

  11. Conversion electron spectroscopy at the FMA focal plane: Decay studies of proton-rich N {approximately} 82 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nisius, D.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    The FMA has proven to be an ideal instrument for the detailed study of the decay of microsecond isomers behind the focal plane following mass selection. In reactions leading to the population of nuclei with isomeric lifetimes longer than their flight time through the device, decay gamma rays and conversion electrons can be detected in an environment free from the backgrounds of prompt radiation and delta electrons. This was a very successful technique to study proton (h{sub 11/2}){sup n} seniority isomers in nuclei with Z > 64 and N {approximately} 82. Since isomeric decay gamma rays are emitted isotropically, conversion electrons are essential for the assignment of multipolarities in these nuclei. Furthermore, the low-energy transitions that depopulate isomeric states are typically highly converted and can escape gamma-ray detection, but they can be identified by their conversion electrons.

  12. Study of the properties of the superheavy nuclei Z=117 produced in the 249Bk + 48Ca reaction

    International Nuclear Information System (INIS)

    Oganessian, Y.T.; Abdullin, F.S.; Dmitriev, S.N.; Itkis, M.G.; Polyakov, A.N.; Sagaidak, R.N.; Shirokovsky, I.V.; Shumeiko, M.V.; Subbotin, V.G.; Sukhov, A.M.; Tsyganov, Y.S.; Utyonkov, V.K.; Voinov, A.A.; Vostokin, G.K.; Alexander, C.; Binder, J.; Boll, R.A.; Ezold, J.; Felker, K.; Miernik, K.; Roberto, J.B.; Rykaczewski, K.P.; Gostic, J.M.; Henderson, R.A.; Moody, K.J.; Shaughnessy, D.H.; Stoyer, M.A.; Stoyer, N.J.; Grzywacz, R.K.; Miller, D.; Hamilton, J.H.; Ramayya, A.V.; Ryabinin, M.A.

    2014-01-01

    The reaction of 249 Bk with 48 Ca have been reinvestigated to provide new evidence for the discovery of element 117 on a larger number of events. The experiments were performed at five projectile energies and with a total beam dose of 48 Ca of about 4.6*10 19 . Two isotopes 293,294 117 were synthesized in the 249 Bk+ 48 Ca reaction, providing excitation functions and α-decay spectra of the produced isotopes that establishes these nuclei to be the products of the 4n- and 3n-evaporation channels, respectively. Decay properties of 293,294 117 and of all the daughter products agree with the data of the experiment in which these nuclei were synthesized for the first time in 2010. The new 289 115 events, populated by a decay of 293 117, demonstrate the same decay properties as those observed for 289 115 produced in the 243 Am( 48 Ca,2n) reaction thus providing cross-bombardment evidence. In addition, a single decay of 294 118 was observed from the reaction with 249 Cf - a result of the in-growth of 249 Cf in the 249 Bk target. (authors)

  13. Asymptotic giant branch stars as producers of carbon and of neutron-rich isotopes

    International Nuclear Information System (INIS)

    Iben, I. Jr.

    1984-01-01

    Carbon stars are thought to be in the asymptotic giant branch (AGB) phase of evolution, alternately burning hydrogen and helium in shells above an electron-degenerate carbon-oxygen (CO) core. The excess of carbon relative to oxygen at the surfaces of these stars is thought to be due to convective dredge-up which occurs following a thermal pulse. During a thermal pulse, carbon and neutron-rich isotopes are made in a convective helium-burning zone. In model stars of large CO core mass, the source of neutrons for producing the neutron-rich isotopes is the 22 Ne(α,n) 25 Mg reaction and the isotopes are produced in the solar system s-process distribution. In models of small core mass, the 13 C(α,n) 16 reaction is thought to be responsible for the release of neutrons, and the resultant distribution of neutron-rich isotopes is expected to vary considerably from one star to the next, with the distribution in isolated instances possibly resembling the solar system distribution of r-process isotopes

  14. Coulomb excitation of neutron-rich$^{28,29,30}$Na nuclei with MINIBALL at REX-ISOLDE: Mapping the borders of the island of inversion

    CERN Multimedia

    Butler, P; Cederkall, J A; Reiter, P; Wiens, A; Blazhev, A A; Kruecken, R; Voulot, D; Kalkuehler, M; Wadsworth, R; Gernhaeuser, R A; Hess, H E; Holler, A; Finke, F; Leske, J; Huyse, M L; Seidlitz, M

    We propose to study the properties of neutron-rich nuclei $^{28,29,30}$Na via Coulomb excitation experiments using the REX-ISOLDE facility coupled with the highly efficient MINIBALL array. Reliable B(E2,0$^{+}$ $\\rightarrow$ 2$^{+}$) values for $^{30,32}$Mg were obtained at ISOLDE. Together with recent new results on $^{31}$Mg, collective and single particle properties are probed for Z=12 at the N=20 neutron closed shell, the 'island of inversion'. We would like to extend this knowledge to the neighbouring $^{28,29,30}$Na isotopes where a different transition from the usual filling of the neutron levels into the region with low lying 2p-2h cross shell configurations is predicted by theory. Detailed theoretical predictions on the transition strength in all three Na nuclei are awaiting experimental verification and are the subject of this proposal. At REX beam energies of 3.0 MeV /nucleon the cross-sections for Coulomb excitation are sufficient. Moreover the results from the close-by $^{30,31,32}$Mg nuclei de...

  15. Reaction cross section measurements of neutron-rich exotic nuclei in the vicinity of closed shells N=20 and N=28

    International Nuclear Information System (INIS)

    Khouaja, A.

    2003-12-01

    Using the direct method, the mean energy integrated reaction cross section was investigated for a wide range of neutron-rich nuclei (N → Ar) at GANIL. Using the parametrisation of S. Kox, 19 new radii measurements (reaction cross sections) were obtained. By the isotopic, isotonic and isospin dependence, the evolution of the strong reduced radius was studied according to the excess of neutrons. New halo effect is proposed to the nuclei of Mg 35 and S 44 . A quadratic parametrization is also proposed for the nuclear radius as a function of the isospin in the region of closed shells N=8 and N=28. In addition, we used a modified version of the Glauber model for studying the tail and matter distribution of nuclei. Indeed, using our new data the effects of the nuclear size (root mean square radii) and the matter distribution (diffusivity) were de-convoluted for each isotope. The root mean square radii of Na and Mg isotopes obtained so far were consistent with the ones from literature. (author)

  16. Pairing in exotic neutron-rich nuclei near the drip line and in the crust of neutron stars

    Science.gov (United States)

    Pastore, A.; Margueron, J.; Schuck, P.; Viñas, X.

    2013-09-01

    Exotic and drip-line nuclei as well as nuclei immersed in a low-density gas of neutrons in the inner crust of neutron stars are systematically investigated with respect to their neutron pairing properties. This is done using Skyrme density-functional and different pairing forces such as a density-dependent contact interaction and a separable form of a finite-range Gogny interaction. Hartree-Fock-Bogoliubov (HFB) and Bardeen-Cooper-Schrieffer (BCS) theories are compared. It is found that neutron pairing is reduced towards the drip line while overcast by strong shell effects. Furthermore, resonances in the continuum can have an important effect counterbalancing the tendency of reduction and leading to a persistence of pairing at the drip line. It is also shown that in these systems the difference between HFB and BCS approaches can be quantitatively large.

  17. Projectile fragmentation of neutron-rich nuclei on light target (momentum distribution and nucleon-removal cross section)

    International Nuclear Information System (INIS)

    Kobayashi, T.; Tanihata, I.; Suzuki, T.

    1992-01-01

    Transverse momentum distributions of the projectile fragments from β-unstable nuclei have been measured with various projectile and target combinations. The momentum correlation of two neutrons in the neutron halo is extracted from the P c t distribution of 9 Li and hat of the neutrons. It is found that the two neutrons are moving in the same direction on average and thus strongly suggests the formation of a di-neutron in 11 Li. (Author)

  18. Some aspects of the use of deep inelastic transfer reactions to produce nuclei far from stability and nuclei with large angular momenta

    International Nuclear Information System (INIS)

    Volkov, V.V.

    1980-01-01

    Some experimental data are considered that indicate the validity of the Q/sub gg/ systematics of cross sections for production of isotopes in multinucleon transfer reactions for any target-projectile combination. The effect of the nuclear structure of the light fragment on the evolution and disintegration of the double nuclear system formed in deep inelastic collisions of complex nuclei is discussed. Predominance of the α-particle emission over all other channels of the disintegration of the double nuclear system is demonstrated. It is shown that deep inelastic transfer reactions can be used to study the deformation of nuclei with large angular momenta. 9 figures

  19. Total reaction cross sections and neutron-removal cross sections of neutron-rich light nuclei measured by the COMBAS fragment-separator

    Science.gov (United States)

    Hue, B. M.; Isataev, T.; Erdemchimeg, B.; Artukh, A. G.; Aznabaev, D.; Davaa, S.; Klygin, S. A.; Kononenko, G. A.; Khuukhenkhuu, G.; Kuterbekov, K.; Lukyanov, S. M.; Mikhailova, T. I.; Maslov, V. A.; Mendibaev, K.; Sereda, Yu M.; Penionzhkevich, Yu E.; Vorontsov, A. N.

    2017-12-01

    Preliminary results of measurements of the total reaction cross sections σR and neutron removal cross section σ-xn for weakly bound 6He, 8Li, 9Be and 10Be nuclei at energy range (20-35) A MeV with 28Si target is presented. The secondary beams of light nuclei were produced by bombardment of the 22Ne (35 A MeV) primary beam on Be target and separated by COMBAS fragment-separator. In dispersive focal plane a horizontal slit defined the momentum acceptance as 1% and a wedge degrader of 200 μm Al was installed. The Bρ of the second section of the fragment-separator was adjusted for measurements in energy range (20-35) A MeV. Two-neutron removal cross sections for 6He and 10Be and one -neutron removal cross sections 8Li and 9Be were measured.

  20. Hydrocarbon-Rich Territories in Central Asia: Producing Countries, Exporting Enclaves or Transit Countries?

    Directory of Open Access Journals (Sweden)

    Aurelia Mañé

    2005-10-01

    Full Text Available This article aims to qualify the different analyses and currents of opinion that are circulating with respect to Central Asia’s capacity to become one of the main exporters of hydrocarbons in the next decade. For this, it first examines whether or not, in quantitativeterms, the hydrocarbon-rich territories of Central Asia can become one of the main suppliers on a world scale; secondly, it explains why the countries of Central Asia will play a necessarily different role on the international energy scene than that played by the OPEC countries; and, finally, it indicates what the relevance of this area could be in the organisation (structure of the contemporary international energy scene. In this sense, it discusses not producing countries, but rather countries of passage.

  1. Seniority isomerism in proton-rich N=82 nuclei and its indication to stiffness of the Z=64 subshell

    International Nuclear Information System (INIS)

    Matsuzawa, T.; Nakada, H.; Ogawa, K.; Momoki, G.

    2000-01-01

    The 10 + and 27/2 - isomers of the Z > 64, N=82 nuclei are investigated in the shell model framework. We derive an extended seniority reduction formula (ExSRF) for the relevant E2 transition strengths. We argue that the B(E2) data based on the ExSRF require the proton excitation from 146 Gd core. The energy levels and the B(E2) values are reproduced simultaneously by a multi-j shell model calculation, if the excitations from (0g 7/2 1d 5/2 ) to (2s 1/2 0h 11/2 1d 3/2 ) are taken into account. (author)

  2. Level structure of 68149Er81 and high-spin isomerism in proton-rich N=81, 82, 83 nuclei

    International Nuclear Information System (INIS)

    Broda, R.; Daly, P.J.; McNeill, J.; Janssens, R.V.F.; Radford, D.C.

    1987-01-01

    The level structure of the N=81 nucleus 149 Er has been studied by γ-ray spectroscopy following the reaction 92 Mo+255 MeV 60 Ni. Yrast levels in 149 Er are established up to ≅ 3.3 MeV, including 0.61 and 4.8 μs isometric states. Most of the observed levels are interpreted as seniority-three states arising from the coupling of s 1/2 , d 3/2 and h 11/2 neutron holes with πh n 11/2 . Isomers identified in the reaction 96 Ru+255 MeV 58 Ni are tentatively assigned to 151 Yb. The B(E2) values of high-spin isomers in Z=66-70, N=81-83 nuclei are surveyed. (orig.)

  3. Microscopic description of the competition between spontaneous fission and α -decay in neutron-rich Ra, U and Pu nuclei

    International Nuclear Information System (INIS)

    Rodríguez-Guzmán, R; Robledo, L M

    2017-01-01

    Constrained mean-field calculations, based on the Gogny-D1M energy density functional, have been carried out to describe fission in Ra, U and Pu nuclei with neutron number 144 ≤ N ≤ 176. Fission paths, collective masses and zero-point quantum vibrational and rotational corrections are used to compute the spontaneous fission half-lives. We also pay attention to isomeric states along the considered fission paths. Alpha decay half-lives have also been computed using a parametrization of the Viola-Seaborg formula. Though there exists a strong variance of the predicted fission rates with respect to the details involved in their computation a robust trend is obtained indicating, that with increasing neutron number fission dominates over α -decay. Our results also suggest that a dynamical treatment of pairing correlations is required within the microscopic studies of the fission process in heavy nuclear systems. (paper)

  4. Measurement method of activation cross-sections of reactions producing short-lived nuclei with 14 MeV neutrons

    CERN Document Server

    Kawade, K; Kasugai, Y; Shibata, M; Iida, T; Takahashi, A; Fukahori, T

    2003-01-01

    We describe a method for obtaining reliable activation cross-sections in the neutron energy range between 13.4 and 14.9 MeV for the reactions producing short-lived nuclei with half-lives between 0.5 and 30 min. We noted neutron irradiation fields and measured induced activities, including (1) the contribution of scattered low-energy neutrons, (2) the fluctuation of the neutron fluence rate during the irradiation, (3) the true coincidence sum effect, (4) the random coincidence sum effect, (5) the deviation in the measuring position due to finite sample thickness, (6) the self-absorption of the gamma-ray in the sample material and (7) the interference reactions producing the same radionuclides or the ones emitting the gamma-ray with the same energy of interest. The cross-sections can be obtained within a total error of 3.6%, when good counting statistics are achieved, including an error of 3.0% for the standard cross-section of sup 2 sup 7 Al (n, alpha) sup 2 sup 4 Na. We propose here simple methods for measuri...

  5. Production of neutron-rich nuclei in fission induced by neutrons generated by the p+ sup 1 sup 3 C reaction at 55 MeV

    CERN Document Server

    Stroe, L; Andrighetto, A; Tecchio, L B; Dendooven, P; Huikari, J; Pentillä, H; Peraejaervi, K; Wang, Y

    2003-01-01

    Cross-sections for the production of neutron-rich nuclei obtained by neutron-induced fission of natural uranium have been measured. The neutrons were generated by bombarding a sup 1 sup 3 C target with 55 MeV protons. The results, position of the maximum in the (Z, A)-plane, width and magnitude, are very comparable with those where the neutrons are generated by bombardment of natural sup 1 sup 2 C graphite with 50 MeV deuterons. Depending on the geometry of the converter/target assembly the isotope yields, however, are a factor of 2-3 lower due to less efficient production of neutrons per primary projectile, especially at small forward angles. (orig.)

  6. Reaction Dynamics and Nuclear Structure Studies of n-Rich Nuclei Around 48Ca via Deep Inelastic Collisions with Heavy-Ions

    International Nuclear Information System (INIS)

    Leoni, S.

    2011-01-01

    The population and γ decay of neutron rich nuclei around 48 Ca has been measured at Legnaro National Laboratory with the PRISMA-CLARA setup, using deep-inelastic collisions on 64 Ni, at 5.9 MeV/A. The reaction properties of the main products are investigated, focusing on total cross-sections and energy integrated angular distributions. Gamma spectroscopy studies are also performed for the most intense transfer channels, making use of angular distributions and polarization measurements to firmly establish spin and parity of the excited states. In the case of 49 Ca candidates for particle-core couplings are investigated and interpreted on basis of lifetime measurements and comparison with model predictions. (author)

  7. Study of fission barriers in neutron-rich nuclei using the (p,2p) reaction. Status of SAMURAI-experiment NP1306 SAMURAI14

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, Sebastian [TU Munich (Germany); Collaboration: NP1306-SAMURAI14-Collaboration

    2015-07-01

    Violent stellar processes are currently assumed to be a major origin of the elements beyond iron and their abundances. The conditions during stellar explosions lead to the so called r-process in which the rapid capture of neutrons and subsequent β decays form heavier elements. This extension of the nuclei stops at the point when the repulsive Coulomb energy induces fission. Its recycling is one key aspect to describe the macroscopic structure of the r-process and the well known elemental abundance pattern. The RIBF at RIKEN is able to provide such neutron rich heavy element beams and a first test with the primary beam {sup 238}U was performed to understand the response of the SAMURAI spectrometer and detectors for heavy beams. The final goal is the definition of the fission barrier height with a resolution of 1 MeV (in σ) using the missing mass method using (p,2p) reactions in inverse kinematics.

  8. Beta decay and magnetic moments as tools to probe nuclear structure. Study of neutron-rich nuclei around N=40; Decroissance beta et moments magnetiques comme outils pour sonder la structure nucleaire. Etude des noyaux riches en neutrons autour de N=40

    Energy Technology Data Exchange (ETDEWEB)

    Matea, I

    2003-12-01

    The evolution of nuclear structure in nuclei far from the {beta} stability line is one of the 'hot topics' in modern experimental and theoretical nuclear physics. The present thesis is devoted to the study of structure of neutron-rich nuclei around N=40. The evolution of the neutron g9/2 orbital with increasing number of neutrons is one of the key points defining the structure of these nuclei at low excitation energy. We used for this investigation as experimental tools the magnetic dipole moments measurements and the {beta} decay spectroscopy. For the measurement of the gyromagnetic factor of the 9/2{sup +} isomeric state in Fe{sup 61} we have applied the TDPAD method. This method (like most of measurements of nuclear moments) requires an oriented ensemble of nuclei. The orientation of Fe{sup 61m} was achieved via the fragmentation of Ni{sup 64} at 55 MeV/u and the selection of the fragment momentum with the LISE spectrometer at GANIL. The experimental device was specially conceived to preserve the alignment up to the implantation point. The measured value of the g factor was compared with large-scale shell model and Hartree-Fock-Bogoliubov model predictions. The nuclei studied via {beta} decay were produced by the fragmentation of Kr{sup 86} at 58 MeV/u. For the selection of reaction products we used for the first time the LISE2000 spectrometer and for the detection of {gamma} rays four EXOGAM clover detectors. We measured 5 new lifetimes and 4 lifetimes with a higher precision. From the prompt {beta}{gamma} coincidences we identified new states in the daughter nuclei, as it is the case of the first 2{sup +} excited states in Fe{sup 68} and Ni{sup 72}. The results were compared with the predictions of the large-scale shell model. Other transitions were observed for the first time in {beta}{gamma} decay of Ti{sup 60}, Fe{sup 70} and Co{sup 71,73}. (author)

  9. $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

    CERN Document Server

    Fornal, B; Bednarczyk, P; Cieplicka, N; Krolas, W; Maj, A; Leoni, S; Benzoni, G; Blasi, N; Bottoni, S; Bracco, A; Camera, F; Crespi, F; Million, B; Morales, A; Wieland, O; Rusek, K; Lunardi, S; Mengoni, D; Recchia, F; Ur, CA; Valiente-Dobon, J; de France, G; Clement, E; Elseviers, J; Flavigny, F; Huyse, M; Raabe, R; Sambi, S; Van Duppen, P; Sferrazza, M; Simpson, G; Georgiev, G; Sotty, C; Blazhev, A; German, R; Siebeck, B; Seidlitz, M; Reiter, P; Warr, N; Boenig, S; Ilieva, S; Kroell, T; Scheck, M; Thurauf, M; Gernhaeuser, R; Mucher, D; Janssens, R; Carpenter, MP; Zhu, S; Marginean, NM; Balabanski, D; Kowalska, M

    2012-01-01

    $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

  10. Investigation of neutron-rich rare-earth nuclei including the new isotopes 177Tm and 184Lu

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Gippert, K.L.; Runte, E.; Schmidt-Ott, W.D.; Tidemand-Petersson, P.; Kurcewicz, W.; Nazarewicz, W.

    1989-01-01

    Decays of neutron-rich isotopes in the rare-earth region were studied by means of on-line mass separation and β-γ spectroscopy using multinucleon-transfer reactions between beams of 136 Xe (9 and 11.7 MeV/u), 186 W (11.7 and 15 MeV/u) and 238 U (11.4 MeV/u) and targets of nat W and Ta. The higher beam energies appear to be advantageous for the production of such isotopes. Two new isotopes were identified: 177 Tm with a half-life T 1/2 = 85±10/15 s, and 184 Lu with T 1/2 ≅ 18 s. A new 47 s-activity found at A = 171 is tentatively assigned to the decay of the new isotope 171 Ho. The properties of the ground and excited states of neutron-rich lanthanide isotopes are interpreted within the shell model using the deformed Woods-Saxon potential. A change of the ground-state configuration for odd-mass neutron-rich lutetium isotopes from π 7/2 + [404] to π 9/2 - [514] is suggested, this change being due to the influence of a large hexadecapole deformation. The role of a possible isometric state in 180 Lu for the nucleosynthesis of 180m Ta is discussed. (orig.)

  11. Nuclear structure studies of neutron-rich heavy nuclei by mass measurements of francium and radium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbusch, Marco [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, 17487 Greifswald (Germany); Collaboration: ISOLTRAP-Collaboration

    2013-07-01

    The mass is a unique property of an atomic nucleus reflecting its binding energy and thus the sum of all interactions at work. Precise measurements of nuclear masses especially of short-lived exotic nuclides provide important input for nuclear structure, nuclear astrophysics, tests of the Standard Model, and weak interaction studies. The Penning-trap mass spectrometer ISOLTRAP at the on-line isotope separator ISOLDE/CERN has been set up for precision mass measurements and continuously improved for accessing more exotic nuclides. The mass uncertainty is typically δm / m=10{sup -8} and the accessible half-life has been reduced to about 50 ms. In this contribution, the results of a measurement campaign of neutron-rich francium and radium isotopes will be presented, i.e. the masses of the isotopic chain of {sup 224-233}Fr and {sup 233,234}Ra, one of the most neutron-rich ensemble obtainable at ISOL facilities. The mass {sup 234}Ra denotes the heaviest mass ever measured with ISOLTRAP. Experimental data in the neutron-rich, heavy mass region is of great interest for studies of structural evolution far from stability, especially because the knowledge from nuclear mass models is scarce. The impact of the new data on the physics in this mass region as well as recent technical developments of ISOLTRAP are discussed.

  12. Measurement of cross sections producing short-lived nuclei by 14 MeV neutron. Br, Te, Dy, Ho, Yb

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Matsumoto, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1997-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 2 min and 57 min have been measured at energy range between 13.4 and 14.9 MeV for Br, Te, Dy, Ho, Yb. The cross sections of {sup 81}Br(n,p){sup 81m}Se, {sup 128}Te(n,p){sup 128m}Sb, {sup 128}Te(n,{alpha}){sup 125m}Sn, {sup 164}Dy(n,p){sup 164}Tb, {sup 165}Ho(n,{alpha}){sup 162}Tb, {sup 176}Yb(n,p){sup 176}Tm were newly obtained at the six energy points between 13.4-14.9 MeV, although the previous results have been obtained at one energy point. {sup 79}Br(n,2n){sup 78}Br, {sup 164}Dy(n,p){sup 164}Tb are compared with evaluated data of JENDL-3.2. The evaluations for these reactions agree reasonably well with experimental results. The cross sections of (n,p) reaction are compared with systematics by Kasugai et. al. The systematics agrees with experimental results. (author)

  13. Correlations of secondary pions produced in multinucleon interactions of π- mesons with carbon nuclei at 40 GeV/c

    International Nuclear Information System (INIS)

    Batskovich, S.; Grishin, V.G.; Jenik, L.; Kanarek, T.

    1979-01-01

    Values of correlation functions are obtained for two-and three particle inclusive processes in π - p, π - n and π -12 C collisions at p=40 GeV/c. The results are obtained while analyzing 9940 π - p, 3590 π - n and approximately 11000 π 12 C inelastic interactions. Correlation values are obtained for various combinations of charged particles. Correlation value at different values of Q is also given for π -12 C events, Q being equal to the difference of positive and negative pions in the given event. Azimuthal correlations are studied for π + π + , π + π - and π - π - pairs, produced in π - p, π - n and π -12 C interactions. The correlations were studied in various ranges of particle rates and at various values of Q. Experimental data on azimuthal correlations are tabulated. The results of correlation measurements over rates and azimuthal angle in π -12 C collisions confirm predictions of the additive quark model and contradict the eikonal model. Measurements of correlation functions is emphasized to be the most sensitive way providing a possibility to find out the source of correlation on nuclei

  14. Treating ammonium-rich wastewater with sludge from water treatment plant to produce ammonium alum

    Directory of Open Access Journals (Sweden)

    Wen-Po Cheng

    2016-03-01

    Full Text Available This study applies a process to treat ammonium-rich wastewater using alum-generated sludge form water purification plant, and gain economic benefit by producing ammonium alum (Al(NH4(SO42·12H2O. The factors affecting production of ammonium alum include molar ratio of ammonium to aluminum concentration, sulfuric acid concentration, mixing speed, mixing time, standing time, and temperature. According to the equation for the ammonium removal reaction, the theoretical quantity of ammonium alum was calculated based on initial and final concentrations of ammonium. Then, the weight of ammonium alum crystal was divided by the theoretical weight to derive the recovery ratio. The optimum sludge and sulfuric acid dosage to treat about 17 g L−1 ammonium wastewater are 300 g L−1 and 100 mL L−1, respectively. The optimal dosage for wastewater is molar ratio of ammonium to aluminum of about 1 due to the aluminum dissolving in acidified wastewater. The ammonium removal efficiency is roughly 70% and the maximum recovery ratio for ammonium alum is 93% when the wastewater is mixed for 10 min at the mixing velocity gradient of 100 s−1. Ammonium alum production or ammonium removal can be enhanced by controlling the reaction at low temperatures.

  15. Phytoplankton Do Not Produce Carbon-Rich Organic Matter in High CO2 Oceans

    Science.gov (United States)

    Kim, Ja-Myung; Lee, Kitack; Suh, Young-Sang; Han, In-Seong

    2018-05-01

    The ocean is a substantial sink for atmospheric carbon dioxide (CO2) released as a result of human activities. Over the coming decades the dissolved inorganic C concentration in the surface ocean is predicted to increase, which is expected to have a direct influence on the efficiency of C utilization (consumption and production) by phytoplankton during photosynthesis. Here we evaluated the generality of C-rich organic matter production by examining the elemental C:N ratio of organic matter produced under conditions of varying pCO2. The data used in this analysis were obtained from a series of pelagic in situ pCO2 perturbation studies that were performed in the diverse ocean regions and involved natural phytoplankton assemblages. The C:N ratio of the resulting particulate and dissolved organic matter did not differ across the range of pCO2 conditions tested. In particular, the ratio for particulate organic C and N was found to be 6.58 ± 0.05, close to the theoretical value of 6.6.

  16. Study of neutron-rich nuclei structure around the N=28 shell closure using the in-beam gamma spectroscopy technique

    International Nuclear Information System (INIS)

    Bastin, B.

    2007-10-01

    For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, 42 Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in 42 Si, combined with the observation of 38,40 Si and the spectroscopy of 41,43 P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure. (author)

  17. Coupling of anaerobic waste treatment to produce protein- and lipid-rich bacterial biomass

    Science.gov (United States)

    Steinberg, Lisa M.; Kronyak, Rachel E.; House, Christopher H.

    2017-11-01

    Future long-term manned space missions will require effective recycling of water and nutrients as part of a life support system. Biological waste treatment is less energy intensive than physicochemical treatment methods, yet anaerobic methanogenic waste treatment has been largely avoided due to slow treatment rates and safety issues concerning methane production. However, methane is generated during atmosphere regeneration on the ISS. Here we propose waste treatment via anaerobic digestion followed by methanotrophic growth of Methylococcus capsulatus to produce a protein- and lipid-rich biomass that can be directly consumed, or used to produce other high-protein food sources such as fish. To achieve more rapid methanogenic waste treatment, we built and tested a fixed-film, flow-through, anaerobic reactor to treat an ersatz wastewater. During steady-state operation, the reactor achieved a 97% chemical oxygen demand (COD) removal rate with an organic loading rate of 1740 g d-1 m-3 and a hydraulic retention time of 12.25 d. The reactor was also tested on three occasions by feeding ca. 500 g COD in less than 12 h, representing 50x the daily feeding rate, with COD removal rates ranging from 56-70%, demonstrating the ability of the reactor to respond to overfeeding events. While investigating the storage of treated reactor effluent at a pH of 12, we isolated a strain of Halomonas desiderata capable of acetate degradation under high pH conditions. We then tested the nutritional content of the alkaliphilic Halomonas desiderata strain, as well as the thermophile Thermus aquaticus, as supplemental protein and lipid sources that grow in conditions that should preclude pathogens. The M. capsulatus biomass consisted of 52% protein and 36% lipids, the H. desiderata biomass consisted of 15% protein and 7% lipids, and the Thermus aquaticus biomass consisted of 61% protein and 16% lipids. This work demonstrates the feasibility of rapid waste treatment in a compact reactor design

  18. Study of shell closures N=40 and N=50 in neutron-rich nuclei; Etude des fermetures de couches N=40 et N=50 dans les noyaux riches en neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Perru, O

    2004-12-01

    For this thesis I have studied 2 neutron shell closures: N=40 and N=50. On N=50, an experiment was done in February 2001 on the ISOL line PARRNe, the issue was to measure the first excited states of {sup 83}Ge (Z=32, N=51) by studying the beta decay of {sup 83}Ga produced by fission of {sup 238}U.The extreme precision of the experimental device, with the operation of hot plasma ion sources made it possible to reach spectroscopic information of the Ge isotopes beyond the magic gap N=50. Two transitions have been attributed to {sup 83}Ge: at 867 keV and at 1238 keV. The level scheme of {sup 83}Ge could be interpreted in terms of weak coupling: the excited states of this nucleus are due to the couplings between the single neutron beyond N=50 and the remaining nucleons.On N=40, we wanted to determine the transition probability between ground state and first excited state, called B(E2), in {sup 70}Ni (N=42) and {sup 74}Zn (N=44) from Coulomb excitation. These exotic nuclei are produced by fragmentation of a primary beam of {sup 76}Ge on a target of {sup 58}Ni, selected by the spectrometer LISE, then interact with a secondary {sup 208}Pb target to induce the Coulomb excitation. At the end of this analysis, the following values have been obtained: B(E2,{sup 70}Ni)=860(170) e{sup 2}fm{sup 4}, B(E2,{sup 74}Zn)=1960(140) e{sup 2}fm{sup 4}. These values have been compared on the one hand to variational calculations which I have realised, on the other hand to published shell model calculations.These calculations point out the complex aspect of the Ni nuclei, which do not seem to have a typical behaviour of semi magic nuclei although they are located on a closed shell in protons (Z=28). (author)

  19. Cluster structures in light nuclei

    International Nuclear Information System (INIS)

    Horiuchi, H.

    2000-01-01

    Complete text of publication follows. Clustering in neutron-rich nuclei is discussed. To understand the novel features (1,2,3) of the clustering in neutron-rich nuclei, the basic features of the clustering in stable nuclei (4) are briefly reviewed. In neutron-rich nuclei, the requirement of the stability of clusters is questioned and the threshold rule is no more obeyed. Examples of clustering in Be and B isotopes (4,5) are discussed in some detail. Possible existence of novel type of clustering near neutron dripline is suggested (1). (author)

  20. Producing diversity: Agroforests Sustain Avian Richness and Abundance in India's Western Ghats

    Directory of Open Access Journals (Sweden)

    Krithi K Karanth

    2016-09-01

    Full Text Available Globally, protected areas have long been the corner stone of biodiversity conservation efforts. In India’s Western Ghats, small and isolated protected areas are embedded in a matrix of multiple land-uses, most of which include agroforests. These agroforests are being increasingly recognized for their supplementary role in conserving wildlife. We examined bird species richness and densities in areca (Areca catechu, coffee (Coffea arabica and Coffea canephora and rubber (Hevea brasiliensis agroforests in the Western Ghats. We developed a priori hypotheses, predicting that bird species richness and guild density would be highest in coffee, followed by areca and rubber agroforests. We carried out 551 point-count surveys involving 386 hours of sampling in 187 agroforests across a 29,634 km2 area of the Ghats. We observed 204 bird species, of which 170 were residents. The average estimated richness per agroforest was higher in coffee (60.5 compared to rubber (45.4 and areca (34.1. We modeled species richness as a function of relevant biogeographic and environmental covariates. The most influential factors were tree cover, tree density and rainfall in all agroforests, but the strength of these effects varied. Coffee supported higher densities in all four habitat and three feeding guilds compared to areca and rubber. We integrated extensive field sampling with modeling that accounted for imperfect detection, while assessing bird richness and densities across multiple agroforest types. We establish that coffee agroforests are substantially richer in birds than rubber and areca, but all three agroforests play an important role in providing subsidiary habitats for birds in the Ghats. Policy decisions and markets must incorporate such biodiversity values and services provided by these agroforests to sustain and facilitate long-term biodiversity conservation.

  1. Measurement of ground state properties of neutron-rich nuclei on the r-process path between the N=50 and N=82 shells

    CERN Multimedia

    2007-01-01

    The evolution of the unknown ground-state ${\\beta}$-decay properties of the neutron-rich $^{84-89}$Ge, $^{90-93}$Se and $^{102-104}$Sr isotopes near the r-process path is of high interest for the study of the abundance peaks around the N=50 and N=82 neutron shells. At ISOLDE, beams of certain elements with sufficient isotopic purity are produced as molecular sidebands rather than atomic beams. This applies e.g, to germanium, separated as GeS$^{+}$, selenium separated as SeCO$^{+}$ and strontium separated as SrF$^{+}$. However, in case of neutron-rich isotopes produced in actinide targets, new "isobaric" background of atomic ions appears on the mass of the molecular sideband. For this particular case, the ECR charge breeder, positioned in the experimental hall after ISOLDE first mass separation, can be advantageously used as a purification device, by breaking the molecules and removing the molecular contaminants. This proposal indicates our interest in the study of basic nuclear structure properties of neutron...

  2. Clusters in nuclei. Vol. 1

    International Nuclear Information System (INIS)

    Beck, Christian

    2010-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is presently one of the domains of heavy-ion nuclear physics facing both the greatest challenges and opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physics decided to team up in producing a comprehensive collection of lectures and tutorial reviews covering the field. This first volume, gathering seven extensive lectures, covers the follow topics: - Cluster Radioactivity - Cluster States and Mean Field Theories - Alpha Clustering and Alpha Condensates - Clustering in Neutron-rich Nuclei - Di-neutron Clustering - Collective Clusterization in Nuclei - Giant Nuclear Molecules By promoting new ideas and developments while retaining a pedagogical nature of presentation throughout, these lectures will both serve as a reference and as advanced teaching material for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  3. Study of the isomer nuclei produced in the spontaneous fission of {sup 252}Cf; Etude des noyaux isomeriques produits dans la fission spontanee de {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Thiesen, Ch. [Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Belier, G.; Girod, M.; Meot, M.V. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, G.; Meot, V.; Peru, S. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Inst.de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-06-01

    Isomeric states have been studied in fission fragments produced by spontaneous fission of {sup 252}Cf. 34 isomeric nuclei have been identified by using coincidences between {gamma}-rays detected in EUROGAM II and fission fragments detected in photovoltaic cells. Lifetimes from 20 ns up to 2 {mu}s have been measured. Microscopic interpretation of the isomeric levels discovered has been tried by means of the Hartree-Fock-Bogolyubov procedure using Gogny force. It was found that the {sup 152,154,156}Nd nuclei have prolate deformation in their ground state; the rotational band built on this ground state is well reproduced by the calculation. For these nuclei the 2 quasi-particle excited states energies are above 1 MeV in agreement with the experiment. The computation confirms the similitude of the {sup 156}Nd and {sup 158}Sm isomeric states associated to neutron 2 quasi-particles of J{sup {pi}} K{sup {pi}} = 5{sup -} ({nu} 5/2 (642) x {nu} 5/2 (523)) while such similitude does not occur for the isotone nuclei {sup 154}Nd and {sup 156}Sm. The computation predicts a proton 2 quasi-particle excited states of J{sup {pi}} = 5{sup -}, near the isomeric level measured in {sup 156}Sm but not for that of {sup 154}Nd. Concerning the {sup 152}Nd the calculated level density is very near that of the states measured in the 1.6 to 2.3 MeV interval. However, the lack of precise information on spins and parities of the measured levels does make not possible a confrontation with the calculations. An up-graded equipment implying 32 photovoltaic cells instead of 2 cells is to be developed and installed by the EUROGAM 3 refs.

  4. Measurement of formation cross sections producing short-lived nuclei by 14 MeV neutrons. Pr, Ba, Ce, Sm, W, Sn, Hf

    International Nuclear Information System (INIS)

    Murahira, S.; Satoh, Y.; Honda, N.; Shibata, M.; Yamamoto, H.; Kawade, K.; Takahashi, A.; Iida, T.

    1996-01-01

    Thirteen neutron activation cross sections for (n,2n), (n,p), (n,np) and (n,α) reactions producing short-lived nuclei with half-lives between 56 s and 24 min were measured in the energy range from 13.4 MeV to 14.9 MeV for Pr, Ba, Ce, Sm, W, Sn and Hf. The cross sections of 179 Hf(n,np) 178m Lu and 180 Hf(n,p) 180 Lu were measured for the first time. (author)

  5. Production and identification of very exotic nuclei

    International Nuclear Information System (INIS)

    Pougheon, F.

    1986-01-01

    New very exotic nuclei have been produced by fragmentation of the projectile at intermediate energy at GANIL. They have been identified through time of flight and ΔE-E measurements after a magnetic separation with the 0 0 LISE spectrometer. New neutron rich isotopes have been identified up to Z = 26 and evidence for the stability of the new series Tz = -5/2 has been shown. These results improve the knowledge of the neutron and proton drip lines

  6. Influence of isovector pairing and particle-number projection effects on spectroscopic factors for one-pair like-particle transfer reactions in proton-rich even-even nuclei

    Science.gov (United States)

    Benbouzid, Y.; Allal, N. H.; Fellah, M.; Oudih, M. R.

    2018-04-01

    Isovector neutron-proton (np) pairing and particle-number fluctuation effects on the spectroscopic factors (SF) corresponding to one-pair like-particle transfer reactions in proton-rich even-even nuclei are studied. With this aim, expressions of the SF corresponding to two-neutron stripping and two-proton pick-up reactions, which take into account the isovector np pairing effect, are established within the generalized BCS approach, using a schematic definition proposed by Chasman. Expressions of the same SF which strictly conserve the particle number are also established within the Sharp-BCS (SBCS) discrete projection method. In both cases, it is shown that these expressions generalize those obtained when only the pairing between like particles is considered. First, the formalism is tested within the Richardson schematic model. Second, it is applied to study even-even proton-rich nuclei using the single-particle energies of a Woods-Saxon mean-field. In both cases, it is shown that the np pairing effect and the particle-number projection effect on the SF values are important, particularly in N = Z nuclei, and must then be taken into account.

  7. Experiments with neutron-rich isomeric beams

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Lewitowicz, M.; Pfuetzner, M.

    1998-01-01

    A review of experimental results obtained on microsecond-isomeric states in neutron-rich nuclei produced in fragmentation reactions and studied with SISSI-Alpha-LISE3 spectrometer system at GANIL Caen is given. The perspectives of experiments based on secondary reactions with isomeric beams are presented

  8. Pseudomagic nuclei

    International Nuclear Information System (INIS)

    Scharff-Goldhaber, G.

    1979-01-01

    It was shown previously that, below a critical angular momentum, yrast bands of nonmagic nuclei are well described by the two-parameter variable moment of inertia model. Some striking exceptions to this rule are found in nuclei which have the same mass number as doubly magic nuclei but possess either one (or two) proton pairs beyond a magic number and one (or two) neutron hole pairs, or vice versa. Yrast bands in these pseudomagic nuclei resemble those in magic nuclei. 17 references

  9. Nano-Second Isomers in Neutron-Rich Ni Region Produced by Deep-Inelastic Collisions

    International Nuclear Information System (INIS)

    Ishii, T.; Asai, M.; Matsuda, M.; Ichikawa, S.; Makishima, A.; Hossain, I.; Kleinheinz, P.; Ogawa, M.

    2001-01-01

    Nuclear structure of the doubly magic 68 Ni and its neighbors has been studied by spectroscopic techniques. Developing a new instrument isomer-scope, we have measured γ rays from nano-second isomers produced in heavy-ion deep-inelastic collisions with great sensitivity. (author)

  10. Half-life determination of T{sub z} = -1 and T{sub z} = -(1)/(2) proton-rich nuclei and the β decay of {sup 58}Zn

    Energy Technology Data Exchange (ETDEWEB)

    Kucuk, L.; Oktem, Y.; Cakirli, R.B.; Ganioglu, E.; Susoy, G. [Istanbul University, Department of Physics, Istanbul (Turkey); Orrigo, S.E.A.; Montaner-Piza, A.; Rubio, B. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Fujita, Y. [Osaka University, Department of Physics, Toyonaka, Osaka (Japan); Osaka University, Research Center for Nuclear Physics, Ibaraki, Osaka (Japan); Gelletly, W. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); University of Surrey, Department of Physics, Guildford, Surrey (United Kingdom); Blank, B.; Ascher, P.; Giovinazzo, J.; Grevy, S. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, CNRS/IN2P3 - Universite de Bordeaux, Gradignan (France); Adachi, T.; Fujita, H.; Tamii, A. [Osaka University, Research Center for Nuclear Physics, Ibaraki, Osaka (Japan); Algora, A. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Inst. of Nuclear Research of the Hung. Acad. of Sciences, Debrecen (Hungary); France, G. de; Oliveira Santos, F. de; Thomas, J.C. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Caen (France); Marques, F.M. [Laboratoire de Physique Corpusculaire de Caen, ENSICAEN, UNICAEN, IN2P3/CNRS, Caen (France); Molina, F. [CSIC-Universidad de Valencia, Instituto de Fisica Corpuscular, Valencia (Spain); Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Perrot, L. [IPN Orsay, Orsay (France); Raabe, R. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Caen (France); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Srivastava, P.C. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Caen (France); Indian Institute of Technology, Department of Physics, Roorkee (India)

    2017-06-15

    We have measured the β-decay half-lives of 16 neutron-deficient nuclei with T{sub z} = -1/2 and -1, ranging from chromium to germanium. They were produced in an experiment carried out at GANIL and optimized for the production of {sup 58}Zn, for which in addition we present the decay scheme and absolute Fermi and Gamow-Teller transition strengths. Since all of these nuclei lie on the rp-process pathway, the T{sub 1/2} values are important ingredients for the rp-process reaction flow calculations and for models of X-ray bursters. (orig.)

  11. Eta mesons in nuclei

    International Nuclear Information System (INIS)

    Liu, L.C.

    1987-01-01

    The possibility of producing eta-mesic nuclei by the use of pions is discussed. If these nuclei are observed experimentally, then the binding energies of the eta in this new nuclear matter can be used to extract accurately the eta-N-N* coupling constant in a nucleus. The framework for these calculations is the coupled channel isobar model

  12. Collectivity of neutron rich Zn nuclei by lifetime measurement with the AGATA demonstrator. Development of a hydrogen target and physics at relativistic energies

    International Nuclear Information System (INIS)

    Louchart, C.

    2012-01-01

    Spectroscopy of exotic nuclei has allowed numerous discoveries in nuclear structure: the shell structure changes and the magic numbers are not persistent when moving toward the drip lines. The study of exotic nuclei requires experimental spectroscopic data which give information on the deformation and the nature of excited states of the studied nucleus. Around 68 Ni, which presents signs of shell closure at N=40 (high excitation energy of the 2 + 1 and low B(E2; 2 + →0 + ) exotic nuclei, like Cr, Fe, Zn and Ge, present deformation and recent experiments point to a rapid development of collectivity. The experiment done at LNL (Laboratori Nazionali di Legnaro) on 70,72,74 Zn isotopes concluded a surprisingly long life time for the 4 + states of 74 Zn, leading to a ratio of B(E2; 4 + → 2 + ) to B(E2; 2 + → 0 + ) very low, not explained by calculations beyond mean field or shell models. This experiment was one of the first with the AGATA demonstrator. Two types of direct reactions are used to extract spectroscopic factors: knockout and low energy transfer reactions. The experimental values are not consistent between the two case s for the removal of one deeply bound nucleon in the nuclei. This difference could come from an incorrect modeling of the reaction mechanism of knockout reactions. Calculations based on intra-nuclear cascade followed by an evaporation phase show weaknesses in the sudden approximation. (author) [fr

  13. Immobilization of chloride-rich radioactive wastes produced by pyrochemical operations

    International Nuclear Information System (INIS)

    McDaniel, E.W.; Terry, J.W.

    1997-08-01

    A a result of its former role as a producer of nuclear weapons components, the Rocky Flats Environmental Technology Site (RFETS), Golden, Colorado accumulated a variety of plutonium-contaminated materials. When the level of contamination exceeded a predetermined level (the economic discard limit), the materials were classified as residues rather than waste and were stored for later recovery of the plutonium. Although large quantities of residues were processed, others, primarily those more difficult to process, remain in storage at the site. It is planned for the residues with lower concentrations of plutonium to be disposed of as wastes at an appropriate disposal facility, probably the Waste Isolation Pilot Plant (WIPP). Because the plutonium concentration is too high or because the physical or chemical form would be difficult to get into a form acceptable to WIPP, it may not be possible to dispose of a portion of the residues at WIPP. The pyrochemical salts are among the residues that are difficult to dispose of. For a large percentage of the pyrochemical salts, safeguards controls are required, but WIPP was not designed to accommodate safeguards controls. A potential solution would be to immobilize the salts. These immobilized salts would contain substantially higher plutonium concentrations than is currently permissible but would be suitable for disposal at WIPP. This document presents the results of a review of three immobilization technologies to determine if mature technologies exist that would be suitable to immobilize pyrochemical salts: cement-based stabilization, low-temperature vitrification, and polymer encapsulation. The authors recommend that flow sheets and life-cycle costs be developed for cement-based and low-temperature glass immobilization

  14. β-Decay half-lives and nuclear structure of exotic proton-rich waiting point nuclei under rp-process conditions

    Science.gov (United States)

    Nabi, Jameel-Un; Böyükata, Mahmut

    2016-03-01

    We investigate even-even nuclei in the A ∼ 70 mass region within the framework of the proton-neutron quasi-particle random phase approximation (pn-QRPA) and the interacting boson model-1 (IBM-1). Our work includes calculation of the energy spectra and the potential energy surfaces V (β , γ) of Zn, Ge, Se, Kr and Sr nuclei with the same proton and neutron number, N = Z. The parametrization of the IBM-1 Hamiltonian was performed for the calculation of the energy levels in the ground state bands. Geometric shape of the nuclei was predicted by plotting the potential energy surfaces V (β , γ) obtained from the IBM-1 Hamiltonian in the classical limit. The pn-QRPA model was later used to compute half-lives of the neutron-deficient nuclei which were found to be in very good agreement with the measured ones. The pn-QRPA model was also used to calculate the Gamow-Teller strength distributions and was found to be in decent agreement with the measured data. We further calculate the electron capture and positron decay rates for these N = Z waiting point (WP) nuclei in the stellar environment employing the pn-QRPA model. For the rp-process conditions, our total weak rates are within a factor two compared with the Skyrme HF +BCS +QRPA calculation. All calculated electron capture rates are comparable to the competing positron decay rates under rp-process conditions. Our study confirms the finding that electron capture rates form an integral part of the weak rates under rp-process conditions and should not be neglected in the nuclear network calculations.

  15. Measurement of cross sections producing short-lived nuclei by 14MeV neutron. Cd, Sn, Te, Nd, Gd, Re

    Energy Technology Data Exchange (ETDEWEB)

    Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

    1998-03-01

    Nine neutron activation cross sections producing the nuclei with half-lives between 25sec and 22min were measured at energy range between 13.4 and 14.9 MeV by activation method. The (n,p) and (n,{alpha}) reaction cross sections were measured for the isotopes of {sup 110}Cd, {sup 112}Sn, {sup 122}Te, {sup 130}Te and {sup 185}Re and those of {sup 130}Te, {sup 148}Nd and {sup 158}Gd, respectively. The present results were compared with our systematics proposed on the basis of 58 cross section data of (n,p) and 33 data of (n,{alpha}) reaction. Good agreements have been seen between them. (author)

  16. Emission of light charged particles from fragments produced on fission of uranium nuclei by 153 MeV protons and 1700 MeV negative pions

    International Nuclear Information System (INIS)

    Belovitzky, G.E.; Shteingrad, O.M.

    2000-01-01

    The mechanism underlying the emission of light charged particles (LCP) with Z = 1, 2 from fragments produced in fission of uranium nuclei by 153 MeV protons and 1700 MeV negative pions was studied. It was found that LCP accompanying the fission by pions are emitted from non-accelerated fragments immediately after the fission, whereas in the case of 153 MeV protons, the LCP are emitted from the accelerated heavy fragments. The number of LCP emitted in the course of pion-induced fission is 0.7 per fission event, which exceeds by a factor of 30 the corresponding number for 153 MeV protons [ru

  17. Structure of neutron-rich nuclei around the N = 126 closed shell; the yrast structure of {sup 205}Au{sub 126} up to spin-parity I{sup {pi}} = (19/2{sup +})

    Energy Technology Data Exchange (ETDEWEB)

    Podolyak, Zs.; Steer, S.J.; Pietri, S.; Regan, P.H.; Brandau, C.; Catford, W.N.; Cullen, I.J.; Gelletly, W.; Jones, G.A.; Liu, Z.; Walker, P.M. [University of Surrey, Department of Physics, Guildford (United Kingdom); Gorska, M.; Gerl, J.; Wollersheim, H.J.; Grawe, H.; Becker, F.; Geissel, H.; Kelic, A.; Kojouharov, I.; Kurz, N.; Montes, F.; Prokopowicz, W.; Saito, T.; Schaffner, H.; Tashenov, S.; Werner-Malento, E. [GSI, Darmstadt (Germany); Rudolph, D.; Hoischen, R. [Lund University, Department of Physics, Lund (Sweden); Garnsworthy, A.B. [University of Surrey, Department of Physics, Guildford (United Kingdom); Yale University, WNSL, New Haven, CT (United States); Maier, K.H. [Institute of Nuclear Physics, Krakow (Poland); University of the West of Scotland, Dept. of Physics, Paisley (United Kingdom); Bednarczyk, P.; Grebosz, J. [GSI, Darmstadt (Germany); Institute of Nuclear Physics, Krakow (Poland); Caceres, L. [GSI, Darmstadt (Germany); Universidad Autonoma de Madrid, Dept. de Fisica Teorica, Madrid (Spain); Doornenbal, P. [GSI, Darmstadt (Germany); Universitaet zu Koeln, IKP, Koeln (Germany); Heinz, A. [Yale University, WNSL, New Haven, CT (United States); Kurtukian-Nieto, T. [Universidad de Santiago de Compostela, Santiago de Campostela (Spain); Benzoni, G.; Wieland, O. [Universita degli Studi di Milano (Italy); INFN, Milano (Italy); Pfuetzner, M. [Warsaw University, IEP, Warsaw (Poland); Jungclaus, A. [Universidad Autonoma de Madrid, Dept. de Fisica Teorica, Madrid (Spain); Balabanski, D.L. [Bulgarian Academy of Sciences, INRNE, Sofia (Bulgaria); Brown, B.A. [Univ. of Surrey, Dept. of Physics, Guildford (United Kingdom); Michigan State Univ., NSCL, East Lansing, MI (United States); Bruce, A.M.; Lalkovski, S. [Univ. of Brighton, School of Environment and Technology, Brighton (United Kingdom); Dombradi, Zs. [Institute for Nuclear Research, Debrecen (Hungary); Estevez, M.E. [Instituto de Fisica Corpuscular, Valencia (Spain)] [and others

    2009-12-15

    Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a {sup 208}{sub 82} Pb beam at E/A = 1 GeV on a 2.5 g/cm{sup 2} thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an {proportional_to}8 mm thick perspex stopper, positioned at the centre of the RISING {gamma} -ray detector spectrometer array. A previously unreported isomer with a half-life T{sub 1/2} = 163(5) ns has been observed in the N=126 closed-shell nucleus {sup 205}{sub 79} Au. Through {gamma}-ray singles and {gamma}-{gamma} coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be I{sup {pi}} = (19/2{sup +}). (orig.)

  18. Sewage sludge based producer gas of rich H{sub 2} content as a fuel for an IC engine

    Energy Technology Data Exchange (ETDEWEB)

    Szwaja, Stanislaw; Cupial, Karol [Czestochowa Univ. of Technology (Poland)

    2010-07-01

    The manuscript presents investigation on hydrogen rich gas combustion in an internal combustion (IC) engine. The gas is obtained from gasification process of sewage sludge which is by-product of waste water treatment in a municipal sewage treatment plant. Recently introduced EU regulations of environmental protection do not allow to use such sludge as a soil fertilizer or substance for landfilling the ground due to its biological toxicity. On another hand, this sludge contains organic content of approximately 45-55% and from this point of view the sludge looks as an attractive material for fuel production through its gasification. This technology, primarily applied for wood gasification, has been also successfully implemented for gasification of sludge. It was found that the producer gas obtained in this way is rich of hydrogen content even up to 25%. This is because of high water content in the sludge that provides favorable conditions for steam reforming resulting in increase of hydrogen in the products of gasification. The high hydrogen content in the producer gas can lead to improper combustion particularly when the combustion takes place in the internal combustion engine. That improper combustion might appear as combustion knock and it is the main problem for the engine in which hydrogen is used as a fuel [1]. Onset of the knock during combustion contributes to rapid increase in heat transfer to the piston crown causing the piston to be quickly overheated that leads to surface erosion and damages. Additionally, engine body vibration coming from the knock significantly shortens engine durability. Conclusions from this investigation provide good premises for combusting the sludge producer gas in the IC engine without any improper combustion anomalies, thus considers this gas as worthy fuel for a stationary engine driven a power generator. The presentation shows results of producer gas combustion in both the spark-ignited and the compression ignition engine with

  19. Acidogenic fermentation characteristics of different types of protein-rich substrates in food waste to produce volatile fatty acids.

    Science.gov (United States)

    Shen, Dongsheng; Yin, Jun; Yu, Xiaoqin; Wang, Meizhen; Long, Yuyang; Shentu, Jiali; Chen, Ting

    2017-03-01

    In this study, tofu and egg white, representing typical protein-rich substrates in food waste based on vegetable and animal protein, respectively, were investigated for producing volatile fatty acids (VFAs) by acidogenic fermentation. VFA production, composition, conversion pathways and microbial communities in acidogenesis from tofu and egg white with and without hydrothermal (HT) pretreatment were compared. The results showed HT pretreatment could improve the VFA production of tofu but not for egg white. The optimum VFA yields were 0.46g/gVS (tofu with HT) and 0.26g/gVS (egg white without HT), respectively. Tofu could directly produce VFAs through the Stickland reaction, while egg white was converted to lactate and VFAs simultaneously. About 30-40% of total protein remained in all groups after fermentation. Up to 50% of the unconverted soluble protein in the HT groups was protease. More lactate-producing bacteria, mainly Leuconostoc and Lactobacillus, were present during egg white fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Study of fp States in Nuclei with High Neutron Excess

    CERN Multimedia

    2002-01-01

    Previous results obtained at ISOLDE on GT transitions in n-rich Na and Mg nuclei have shown the sharp decrease of excitation energy for fp states when A$>$29. \\\\ \\\\ Independently, shell model calculations have revealed that the onset of a deformation region near N=20 for Ne, Na and Mg nuclei was related to a sudden transition in the ground state properties with the appearance of a major (sd)$^{-2}$(fp)$^2$ component. \\\\ \\\\ We propose to use the new possibilities of producing and detecting n-rich nuclei to study by $\\gamma$ and n spectroscopy the properties of fp states with different cores: around N=20 (Na, Mg and Al) and N=28 (Ar, K and Ca). In particular, the cases of $^3

  1. Assessment of canine autologous platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit.

    Science.gov (United States)

    Frye, Chris W; Enders, Andrew; Brooks, Marjory B; Struble, Angela M; Wakshlag, Joseph J

    2016-01-01

    To characterize the cellular composition (platelets, erythrocytes, and leukocytes) and confirm reproducibility of platelet enrichment, as well as determine the platelet activation status in the final product of a commercial platelet-rich plasma kit using canine blood. Venous blood from 20 sedated client-owned dogs was used to prepare platelet-rich plasma (PRP) from a commercial kit. Complete blood counts were performed to determine erythrocyte, leukocyte, and platelet numbers in both whole blood (WB) and resultant PRP. The WB and PRP samples from jugular (fast collection) and cephalic (slow collection) venipuncture were also compared. P-selectin externalization was measured in WB and PRP samples from 15 of 20 dogs. This commercial kit produced an average percent recovery in platelets of 64.7 ± 17.4; erythrocytes of 3.7 ± 0.8, and leukocytes of 31.6 ± 10.0. Neutrophil, monocyte, and lymphocyte percent recovery was 19.6 ± 7.2, 44.89 ± 19.8, and 57.5 ± 10.6, respectively. The recovery of platelets from jugular venipuncture (59.7 ± 13.6%) was lower than from cephalic recovery (68.8 ± 19.1%). The mean percent P-Selectin externalization for WB, PRP, and PRP with thrombin was 25.5 ± 30.9, 4.5 ± 6.4, and 90.6 ± 4.4 respectively. Cellular reproducibility of this kit was confirmed and platelets were concentrated within autologous serum. Additionally, measurements of P-selectin externalization showed that platelets are inactive in PRP unless stimulated to degranulate.

  2. Exotic nuclei

    International Nuclear Information System (INIS)

    Villari, A.C.C.

    1990-01-01

    The actual tendencies to study exotic nuclei; applications of exotic nuclei beams in material study and medicine; recent results obtained by GANIL and Berkeley Laboratories of measurements of binding energy and radii of light nuclei; the future experiences to be carry out in several international laboratories and; proposal of studies in Brazil using Pelletron-USP accelerator and the LINAC superconductor accelerator, in construction in the same laboratory, are presented. (M.C.K.)

  3. Nuclei at the limits of particle stability

    International Nuclear Information System (INIS)

    Mueller, A.C.

    1993-01-01

    The properties and synthesis of nuclei at the limits of particle stability are reviewed. Nuclear reactions were induced and studied by means of the 'exotic' nuclear beams, i.e. beams of radioactive drip-line nuclei. The beams are mostly generated in heavy-ion projectile fragmentation. The cases of both neutron-rich and proton-rich nuclei are discussed. (K.A.) 270 refs.; 13 figs.; 1 tab

  4. An interlaboratory comparison of the performance of ethanol-producing micro-organisms in a xylose-rich acid hydrolysate

    Energy Technology Data Exchange (ETDEWEB)

    Hahn-Haegerdal, B. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Jeppsson, H. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Olsson, L. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Mohagheghi, A. (Bioprocess and Fuels Engineering Research Branch, National Renewable Energy Lab., Golden, CO (United States))

    1994-03-01

    A xylose-rich, dilute-acid-pretreated corn-cob hydrolysate was fermented by Escherichia coli ATCC 11303, recombinant (rec) E. coli B (pLOI 297 and KO11), Pichia stipitis (CBS 5773, 6054 and R), Saccharomyces cerevisiae isolate 3 in combination with xylose isomerase, rec S. cerevisiae (TJ1, H550 and H477) and Fusarium oxysporum VTT-D-80134 in an interlaboratory comparison. The micro-organisms were studied according to three different options: (A) fermentation under consistent conditions. (B) fermentation under optimal conditions for the organism, and (C) fermentation under optimal conditions for the organism with detoxification of the hydrolysate. The highest yields of ethanol, 0.24 g/g (A), 0.36 g/g (B) and 0.54 g/g (C), were obtained from rec E. coli B, KO11. P. stipitis and F. oxysporum were sensitive to the inhibitors present in the hydrolysate and produced a maximum yield of 0.34 g/g (C) and 0.04 g/g (B), respectively. The analysis of the corn-cob hydrolysate and aspects of process economy of the different fermentation options (pH, sterilization, nutrient supplementation, adaptation, detoxification) are discussed. (orig.)

  5. Identification of new proton-rich rare earth nuclei by means of the coupled system helium jet-isotope separator of SARA

    International Nuclear Information System (INIS)

    Ollivier, T.

    1986-01-01

    In order to study new exotic nuclei far from stability we built a fast separation system by coupling a helium jet with the medium-current source of the mass separator. First the tests were made in Lyon and then the system used on line with the heavy ion accelerator SARA, in Grenoble. We obtained efficiency greater than 1% for each element and a better chemical independence. This allowed us to perform experiments on rare-earth region near N=82, with fusion-evaporation reactions after an investigation of various ranges of beam energies. The first results allow to identify two new isotopes, 143 Tb (12s) and 138 Eu (12s). The decay schemes obtained are analysed in the frame of existing models [fr

  6. Measurement of beta decay energies of short-lived neutron rich atomic nuclei in the mass range 101 ≤ A ≤ 106 and A=109

    International Nuclear Information System (INIS)

    Weikard, H.

    1986-01-01

    At the mass separator LOHENGRIN of the Laue-Langevin institute in Grenoble for 18 nuclei (Zr, Nb, Mo, Tc, Ru, and Rh nuclides) with masses 101 ≤ A ≤ 106 and A=109 Q β values were determined from measurement of beta decay energies. From the study of the isomerism in 102 Nb resulted that the energetic distance of the two isomers is certainly smaller than 200 keV, that it is probably even smaller than 100 keV. The decay scheme for 102 Nb could be extended by one level which is depopulated by two gamma lines. For the decay of the 109 Ru the approach of a decay scheme is given: Five new levels are proposed. The diagrams of the two-particle separation energies which could be extended in this thesis confirm the continuation of the deformation in the considered region. A deformed subshell at N=62 however cannot yet be clearly detected. (orig./HSI) [de

  7. Study of some continuous spectra produced by nuclear reactions with light nuclei; Etude de quelques spectres continus produits par reactions nucleaires avec des noyaux legers

    Energy Technology Data Exchange (ETDEWEB)

    Marquez, L

    1966-07-01

    The continuous spectra coming from several nuclear reactions with light nuclei were measured. The spectra can be explained by a two-step reaction mechanism; however, the reactions produced by {sup 6}Li are different. A mechanism was proposed to explain their spectra based on the following assumptions: {sup 6}Li makes a nuclear molecule with the target which subsequently breaks up in such a way that an {alpha} particle comes out with the kinetic energy that it has in the molecule. The calculated spectra and those measured are in good agreement. (author) [French] Nous avons mesure les spectres continus produits dans plusieurs reactions nucleaires avec des noyaux legers. A l'exception des spectres produits par {sup 6}Li, on a trouve qu'on pouvait expliquer ces spectres par le mecanisme des reactions en deux etapes. Nous avons propose un mecanisme pour expliquer les spectres produits par {sup 6}Li. On suppose que {sup 6}Li forme une molecule nucleaire avec la cible qui eclate ensuite de facon telle qu'une particule alpha de la molecule sort avec l'energie cinetique de son mouvement propre dans la molecule. Les spectres calcules avec ces hypotheses et les spectres mesures sont en bon accord. (auteur)

  8. Isotopic distribution of Rb, In and Cs, produced in interactions of high energy protons, deuterons and alpha particles with Ta nuclei

    International Nuclear Information System (INIS)

    Avdeev, S.P.; Karnaukhov, V.A.; Korovin, G.Yu.; Kuznetsov, V.D.; Nad', T.; Petrov, L.A.

    1982-01-01

    The purpose of the paper is to clarify how the isotopical distribution form of deep fissaon products depends on the type of the bombarding particles. Isotopical distributions of Rb, In, Cs, produced at interactions of protons, deuterons ( 8 GeV) and α particles (15.2 GeV) with Ta nuclei are measured by means of the ''off-line'' mass separation. The isotopical distributions are obtained by the experimentally measured yields directly without complex procedure of processing necessary for transition to the charge distribution. It was found that neither the position of the maximum, nor the shape of the curve are changed essentially at variation of the projectile. In all the cases the relative behaviour of the distribution is in a qualitative agreement with the calculations based upon the semiempirical formula by Rudstam. For indium the mesurements are performed also with the proton beam of energy 0.66 GeV. In this case the shape of the isotopic distribution is influenced by the fission process [ru

  9. Gamma-ray spectroscopy of the neutron-rich Ni region through heavy-ion deep-inelastic collisions

    International Nuclear Information System (INIS)

    Ishii, T.; Asai, M.; Matsuda, M.; Ichikawa, S.; Makishima, A.; Hossain, I.; Kleinheinz, P.; Ogawa, M.

    2002-01-01

    Nuclei in the neutron-rich Ni region have been studied by γ-ray spectroscopy. Gamma-rays emitted from isomers, with T 1/2 >1 ns, produced in heavy-ion deep-inelastic collisions were measured with an isomer-scope. The nuclear structure of the doubly magic 68 Ni and its neighbor 69,71 Cu is discussed on the basis of the shell model. Future experiments for more neutron-rich Ni nuclei are also viewed. (orig.)

  10. Gamma-ray spectroscopy of the neutron-rich Ni region through heavy-ion deep-inelastic collisions

    Science.gov (United States)

    Ishii, T.; Asai, M.; Makishima, A.; Hossain, I.; Kleinheinz, P.; Ogawa, M.; Matsuda, M.; Ichikawa, S.

    Nuclei in the neutron-rich Ni region have been studied by γ-ray spectroscopy. Gamma-rays emitted from isomers, with T1/2 > 1 ns, produced in heavy-ion deep-inelastic collisions were measured with an isomer-scope. The nuclear structure of the doubly magic 68Ni and its neighbor 69,71Cu is discussed on the basis of the shell model. Future experiments for more neutron-rich Ni nuclei are also viewed.

  11. Reaction cross section measurements of neutron-rich exotic nuclei in the vicinity of closed shells N=20 and N=28; Mesures de section efficace de reaction de noyaux exotiques riches en neutrons dans la zone de fermeture des couches N=20 et N=28

    Energy Technology Data Exchange (ETDEWEB)

    Khouaja, A

    2003-12-01

    Using the direct method, the mean energy integrated reaction cross section was investigated for a wide range of neutron-rich nuclei (N {yields} Ar) at GANIL. Using the parametrisation of S. Kox, 19 new radii measurements (reaction cross sections) were obtained. By the isotopic, isotonic and isospin dependence, the evolution of the strong reduced radius was studied according to the excess of neutrons. New halo effect is proposed to the nuclei of Mg{sup 35} and S{sup 44}. A quadratic parametrization is also proposed for the nuclear radius as a function of the isospin in the region of closed shells N=8 and N=28. In addition, we used a modified version of the Glauber model for studying the tail and matter distribution of nuclei. Indeed, using our new data the effects of the nuclear size (root mean square radii) and the matter distribution (diffusivity) were de-convoluted for each isotope. The root mean square radii of Na and Mg isotopes obtained so far were consistent with the ones from literature. (author)

  12. Identification of highly deformed even–even nuclei in the neutron- and proton-rich regions of the nuclear chart from the B(E2)↑ and E2 predictions in the generalized differential equation model

    International Nuclear Information System (INIS)

    Nayak, R.C.; Pattnaik, S.

    2015-01-01

    We identify here the possible occurrence of large deformations in the neutron- and proton-rich (n-rich and p-rich) regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B(E2)↑ for the transition from the ground state to the first 2 + state and the corresponding excitation energy E2 of even–even nuclei in the recently developed generalized differential equation (GDE) model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters derived from them such as the quadrupole deformation β 2 , the ratio of β- 2 to the Weisskopf single-particle β 2(sp) and the intrinsic electric quadrupole moment Q 0 , calculated for a large number of both known as well as hitherto unknown even–even isotopes of oxygen to fermium (0 to FM; Z = 8 – 100). Our critical analysis of the resulting data convincingly support possible existence of large collectivity for the nuclides 30,32 Ne, 34 Mg, 60 Ti, 42,62,64 Cr, 50,68 Fe, 52,72 Ni, 72,70,96 Kr, 74,76 Sr, 78,80,106,108 Zr, 82,84,110,112 Mo, 140 Te, 144 Xe, 148 Ba, 122 Ce, 128,156 Nd, 130,132,158,160 Sm and 138,162,164,166 Gd, whose values of β 2 are found to exceed 0.3 and even 0.4 in some cases. Our findings of large deformations in the exotic n-rich regions support the existence of another “island of inversion” in the heavy-mass region possibly caused by breaking of the N = 70 subshell closure. (author)

  13. Study of neutron rich nuclei by delayed neutron decay using the Tonnerre multidetector; Etude de la decroissance par neutrons retardes de noyaux legers riches en neutrons avec le multidetecteur tonnerre

    Energy Technology Data Exchange (ETDEWEB)

    Timis, C.N

    2001-07-01

    A new detection array for beta delayed neutrons was built. It includes up to 32 plastic scintillation counters 180 cm long located at 120 cm from the target. Neutron energy spectra are measured by time-of-flight in the 300 keV-15 MeV range with good energy resolution. The device was tested with several known nuclei. Its performances are discussed in comparison with Monte Carlo simulations. They very high overall detection efficiency on the TONNERRE array made it possible to study one and two neutron emission of {sup 11}Li. A complete decay scheme was obtained. The {sup 33}Mg and {sup 35}Al beta decays were investigated for the first time by neutron and gamma spectroscopy. Complete decay schemes were established and compared to large scale shell-model calculations. (authors)

  14. Low energy resonance in the neutron rich nucleus of 48Ca. New detectors for the study of unstable nuclei: MUST and CATS

    International Nuclear Information System (INIS)

    Ottini, St.

    1998-01-01

    Two new detectors have been developed to study reactions resulting from exotic beams. The first one, MUST, a set of Si strip detectors is devoted to light recoil particles detection between 500 eV and 120 MeV. The 40 Ar elastic and inelastic scattering analysis at 77 MeV per nucleon showed a non ambiguous identification of the particles in the detector, thanks the time and energy resolutions. The second one, CATs, is a set of beam detectors. These low pressure wire chambers allow each particle measurement of the exotic beams with an accuracy of 0,4 mm. A special interest is given to the halo nuclei low excitation energy spectra. A dipolar low energy resonance should be observed. The inelastic scattering at 60 MeV per nucleon on two targets ( 40 Ca and 48 Ca) has been studied with SPEG at Ganil (France), to search a low energy resonance. It is not possible to conclude on this low energy resonance existence. (A.L.B.)

  15. Isolation of Nuclei and Nucleoli.

    Science.gov (United States)

    Pendle, Alison F; Shaw, Peter J

    2017-01-01

    Here we describe methods for producing nuclei from Arabidopsis suspension cultures or root tips of Arabidopsis, wheat, or pea. These methods could be adapted for other species and cell types. The resulting nuclei can be further purified for use in biochemical or proteomic studies, or can be used for microscopy. We also describe how the nuclei can be used to obtain a preparation of nucleoli.

  16. Neutron-capture reactions by stable and unstable neutron-rich nuclei and their relevance for nucleosynthesis in hot and explosive astrophysical scenarios

    International Nuclear Information System (INIS)

    Hofinger, R.

    1997-10-01

    This thesis deals on the one hand with neutron-capture reactions by carbon-, nitrogen-, oxygen- and sulfur-isotopes, and on the other hand with the two-step processes 4 He(2n, γ) 6 He and 9 Li(2n, γ) 11 Li. Some of the involved carbon-, nitrogen- and oxygen-isotopes possess neutron-halos characterized by the unexpected large radial extension of the nuclear matter density distribution. Special attention is paid to the halo properties in the calculation of the direct neutron capture cross section. For the determination of the nuclear structure, models are used, when no experimental information is available. The results for the reaction rates are compared to previously used rates. The rates obtained in this work are partly orders of magnitude higher than the previously used reaction rates. The reaction rates for the two-step processes are on the one hand calculated assuming a two-step process, on the other hand from genuine three-body models for the process of photodisintegration of the nuclei 6 He and 11 Li. It turns out that the calculations assuming a trio-step process underestimate the reaction rates by orders of magnitude. The influence of the reaction rate for the reaction 4 He(2n, γ) 6 He and the formation of 12 C is examined in a nuclear reaction network under conditions which are typical for the α- process in supernovae of type II. It turns out that under these conditions the influence of the reaction 4 He(2n, γ) 6 He is negligible on the formation of 12 C. (author)

  17. X-ray short-time lags in the Fe-K energy band produced by scattering clouds in active galactic nuclei

    Science.gov (United States)

    Mizumoto, Misaki; Done, Chris; Hagino, Kouichi; Ebisawa, Ken; Tsujimoto, Masahiro; Odaka, Hirokazu

    2018-05-01

    X-rays illuminating the accretion disc in active galactic nuclei give rise to an iron K line and its associated reflection spectrum which are lagged behind the continuum variability by the light-travel time from the source to the disc. The measured lag timescales in the iron band can be as short as ˜Rg/c, where Rg is the gravitational radius, which is often interpreted as evidence for a very small continuum source close to the event horizon of a rapidly spinning black hole. However, the short lags can also be produced by reflection from more distant material, because the primary photons with no time-delay dilute the time-lags caused by the reprocessed photons. We perform a Monte-Carlo simulation to calculate the dilution effect in the X-ray reverberation lags from a half-shell of neutral material placed at 100 Rg from the central source. This gives lags of ˜2 Rg/c, but the iron line is a distinctly narrow feature in the lag-energy plot, whereas the data often show a broader line. We show that both the short lag and the line broadening can be reproduced if the scattering material is outflowing at ˜0.1c. The velocity structure in the wind can also give shifts in the line profile in the lag-energy plot calculated at different frequencies. Hence we propose that the observed broad iron reverberation lags and shifts in profile as a function of frequency of variability can arise from a disc wind at fairly large distances from the X-ray source.

  18. Level structures in Yb nuclei far from stable nuclei

    International Nuclear Information System (INIS)

    Hashizume, Akira

    1982-01-01

    Applying n-γ, γ-γ coincidence techniques, the excited levels in 158 Yb and in 157 Yb nuclei were studied. Stress is placed ona neutron detection technique to assign (HI,xn) reactions which produce the nuclei far from β stability line. (author)

  19. Improvements to the on-line mass separator, RAMA, and the beta-delayed charged-particle emission of proton-rich sd shell nuclei

    International Nuclear Information System (INIS)

    Ognibene, T.J.

    1996-03-01

    To overcome the extreme difficulties encountered in the experimental decay studies of proton drip line nuclei, several techniques have been utilized, including a helium-jet transport system, particle identification detectors and mass separation. Improvements to the ion source/extraction region of the He-jet coupled on-line Recoil Atom Mass Analyzer (RAMA) and its target/ion source coupling resulted in significant increases in RAMA efficiencies and its mass resolution, as well as reductions in the overall transit time. At the 88-Inch Cyclotron at LBNL, the decays of 31 Cl, 27 P and 28 P, with half-lives of 150 msec, 260 msec and 270.3 msec, respectively, were examined using a he-jet and low-energy gas ΔE-gas ΔE-silicon E detector telescopes. Total beta-delayed proton branches of 0.3% and 0.07% in 31 Cl and 27 P, respectively, were estimated. Several proton peaks that had been previously assigned to the decay of 31 Cl were shown to be from the decay of 25 Si. In 27 P, two proton groups at 459 ± 14 keV and 610 ± 11 keV, with intensities of 7 ± 3% and 92 ± 4% relative to the main (100%) group were discovered. The Gamow-Teller component of the preceding beta-decay of each observed proton transition was compared to results from shell model calculations. Finally, a new proton transition was identified, following the β-decay of 28 P, at 1,444 ± 12 keV with a 1.7 ± 0.5% relative intensity to the 100% group. Using similar low-energy detector telescopes and the mass separator TISOL at TRIUMF, the 109 msec and 173 msec activities, 17 Ne and 33 Ar, were studied. A new proton group with energy 729 ± 15 keV was observed following the beta-decay of 17 Ne. Several discrepancies between earlier works as to the energies, intensities and assignments of several proton transitions from 17 Ne and 33 Ar were resolved

  20. Study of fission dynamics of the excited nuclei produced in fusion reactions in the framework of the four-dimensional Langevin equations

    Energy Technology Data Exchange (ETDEWEB)

    Eslamizadeh, H. [Persian Gulf University, Department of Physics, Bushehr (Iran, Islamic Republic of)

    2014-12-01

    The dynamics of fission of excited nuclei has been studied by solving four-dimensional Langevin equations with dissipation generated through the chaos-weighted wall and window friction formula. The projection of the total spin of the compound nucleus to the symmetry axis, K, was considered as the fourth dimension in Langevin dynamical calculations. The average pre-scission neutron multiplicities, mean kinetic energy of fission fragments and the variances of the mass and kinetic energy have been calculated in a wide range of fissile parameter for compound nuclei {sup 162}Yb, {sup 172}Yb, {sup 215}Fr, {sup 224}Th, {sup 248}Cf, {sup 260}Rf and results compared with the experimental data. Calculations were performed with a constant dissipation coefficient of K, {sub γK} (MeV zs){sup -1/2}, and with a non-constant dissipation coefficient. Comparison of the theoretical results for the average pre-scission neutron multiplicities, mean kinetic energy of fission fragments and the variances of the mass and kinetic energy with the experimental data showed that the results of four-dimensional Langevin equations with a non-constant dissipation coefficient are in better agreement with the experimental data. Furthermore, the difference between the results of two models for compound nuclei with low fissile parameter is low whereas, for heavy compound nuclei, is high. (orig.)

  1. Establishment of pregnancy after the transfer of nuclear transfer embryos produced from the fusion of argali (Ovis ammon) nuclei into domestic sheep (Ovis aries) enucleated oocytes.

    Science.gov (United States)

    White, K L; Bunch, T D; Mitalipov, S; Reed, W A

    1999-01-01

    by exposure to ionomycin (5 microM, 4 minutes) followed by incubation in 6-dimethylaminopurine (0.2 mM, 4 hours) and cultured in microdrops of CR1aa medium. From a total of 166 constructed nuclear donor cell-bovine cytoplasm NT couples, 128 (77%) successfully fused, 100 (78%) developed to 8-16 cell stage, and 2 (1.56%) developed to the blastocyst stage. The presence of argali nuclei in 8-16 cell stage embryo clones was confirmed after observation of Hoechst 33342 stained embryos under UV light and chromosome analysis of metaphase spreads from blastomeres. A total of 127 constructed nuclear donor cell-ovine cytoplasm NT couples were produced, 101 (80%) successfully fused, 81 (80% of fused) developed to the 16- to 32-cell stage. A total of 28 hybrid (argali-sheep) and 21 sheep-sheep NT embryos were transferred into 6 recipients and 4 recipients, respectively. Two of these recipients, 1 carrying argali-sheep and 1 sheep-sheep, were confirmed pregnant at 49 days by ultrasound, but both pregnancies terminated by 59 days. The results of this study demonstrate the possibility of using xenogenic oocytes to produce early-stage embryos and pregnancies from an established fibroblast cell line of an endangered species.

  2. Superdeformed nuclei

    International Nuclear Information System (INIS)

    Janssens, R.V.F.; Khoo, T.L.

    1991-01-01

    Superdeformation was first proposed some twenty years ago to explain the fission isomers observed in some actinide nuclei. It was later realized that superdeformed shapes can occur at high angular momentum in lighter nuclei. The interest in the mechanisms responsible for these exotic shapes has increased enormously with the discovery of a superdeformed band of nineteen discrete lines in 152 Dy (8). At about the same time, evidence for highly deformed nuclei (axis ratio 3:2) was also reported near 132 Ce(9). Striking properties emerged from the first experiments, such as the essentially constant energy spacing between transitions (picket-fence spectra), the unexpectedly strong population of superdeformed bands at high spins, and the apparent lack of a link between the superdeformed states and the yrast levels. These findings were reviewed by Nolan and Twin. The present article follows upon their work and discusses the wealth of information that has since become available. This includes the discovery of a new island of superdeformation near A = 190, the detailed spectroscopy of ground and excited bands in the superdeformed well near A = 150 and A = 190, the surprising occurrence of superdeformed bands with identical transition energies in nuclei differing by one or two mass units, and the improved understanding of mechanisms responsible for the feeding into and the decay out of the superdeformed states

  3. Cosmology and unstable nuclei

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1995-01-01

    Primordial nucleosynthesis has established itself as one of the three pillars of Big Bang cosmology. Many of the Big Bang Nucleosynthesis reactions involve unstable nuclei. Hence there is a tight relationship hetween the subject of this conference and cosmology. The prime role of unstable nuclei in cosmology is related to lithium synthesis and the lack of cosmological synthesis of Be and B. These nuclei will thus be focused upon. Nucleosynthesis involves comparing calculated abundances with observed abundances. In general, abundance determinations are dominated by systematic rather than statistical errors, and work on bounding systematics is crucial. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ω b are possible vis-a-vis the homogeneous model; hence the robustness of Ω b ∼0.05 is now apparent. (These calculations depend critically on unstable nuclei.) The above argues that the bulk of the baryons in the universe are not producing visible light. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ω b ∼1 seems to be definitely excluded, so if Ω TOTAL =1, as some recent observations may hint, then non-baryonic dark matter is required. The implications of the recently reported halo microlensing events are discussed. In summary, it is argued that the physics of unstable nuclei affects the fundamental dark matter argument. ((orig.))

  4. Mean-field models and exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M; Buervenich, T; Maruhn, J A; Greiner, W [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P G [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)

    1998-06-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  5. Microscopic Cluster Theory for Exotic Nuclei

    International Nuclear Information System (INIS)

    Tomaselli, M; Kuehl, T; Ursescu, D; Fritzsche, S

    2006-01-01

    For a better understanding of the dynamics of complex exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. In this paper we propose to calculate the structure of neutron-rich nuclei within a dynamic model based on the EoM theory

  6. Mean-field models and exotic nuclei

    International Nuclear Information System (INIS)

    Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W.; Rutz, K.; Reinhard, P.G.

    1998-01-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  7. The asymptotic hadron spectrum, anti-nuclei, hyper-nuclei and quark phase

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1978-01-01

    The only hope of determining the hadronic spectrum in the high mass region is through a study of matter produced in very high energy nuclear collisions. Along the way, exotic nuclei, i.e., anti-nuclei and hyper-nuclei may be produced in appreciable numbers, and the detection of a quark phase may be possible. (orig.) [de

  8. Experimental and theoretical study of the yields of residual product nuclei produced in thin targets irradiated by 100-2600 MeV protons

    CERN Document Server

    Titarenko, Y E; Karpikhin, E I

    2003-01-01

    The objective of the project is measurements and computer simulations of independent and cumulative yields of residual product nuclei in thin targets relevant as target materials and structure materials for hybrid accelerator-driven systems coupled to high-energy proton accelerators. The yields of residual product nuclei are of great importance when estimating such basic radiation-technology characteristics of hybrid facility targets as the total target activity, target 'poisoning', buildup of long-lived nuclides that, in turn, are to be transmuted, product nuclide (Po) alpha-activity, content of low-pressure evaporated nuclides (Hg), content of chemically-active nuclides that spoil drastically the corrosion resistance of the facility structure materials, etc. In view of the above, radioactive product nuclide yields from targets and structure materials were determined by an experiment using the ITEP U-10 proton accelerator in 51 irradiation runs for different thin targets: sup 1 sup 8 sup 2 sup , sup 1 sup 8 ...

  9. Positron annihilation studies of silicon-rich SiO2 produced by high dose ion implantation

    International Nuclear Information System (INIS)

    Ghislotti, G.; Nielsen, B.; Asoka-Kumar, P.; Lynn, K.G.; Di Mauro, L.F.; Corni, F.; Tonini, R.

    1997-01-01

    Positron annihilation spectroscopy (PAS) is used to study Si-rich SiO 2 samples prepared by implantation of Si (160 keV) ions at doses in the range 3x10 16 endash 3x10 17 cm -2 and subsequent thermal annealing at high temperature (up to 1100 degree C). Samples implanted at doses higher than 5x10 16 cm -2 and annealed above 1000 degree C showed a PAS spectrum with an annihilation peak broader than the unimplanted sample. We discuss how these results are related to the process of silicon precipitation inside SiO 2 . copyright 1997 American Institute of Physics

  10. Colliding nuclei

    International Nuclear Information System (INIS)

    Balian, Roger; Remaud, Bernard; Suraud, E.; Durand, Dominique; Tamain, Bernard; Gobbi, A.; Cugnon, J.; Drapier, Olivier; Govaerts, Jan; Prieels, Rene

    1995-09-01

    This 14. international school Joliot-Curie of nuclear physic deals with nuclei in collision at high energy. Nine lectures are included in the proceedings of this summer school: 1 - From statistical mechanics outside equilibrium to transport equations (Balian, R.); 2 - Modeling of heavy ions reactions (Remaud, B.); 3 - Kinetic equations in heavy ions physics (Suraud, E.); 4 - Colliding nuclei near the Fermi energy (Durand, D.; Tamain, B.); 5 - From the Fermi to the relativistic energy domain: which observable? For which physics? (Gobbi, A.); 6 - Collisions at relativistic and ultra relativistic energies, Theoretical aspects (Cugnon, J.); 7 - Quark-gluon plasma: experimental signatures (Drapier, O.); 8 - Electroweak interaction: a window on physics beyond the standard model (Govaerts, J.); 9 - Symmetry tests in β nuclear process: polarization techniques (Prieels, R.)

  11. Collisions with nuclei

    International Nuclear Information System (INIS)

    Gulamov, K.G.

    1987-01-01

    It is well known that interactions of high energy particles with nuclei, owing to possible intranuclear rescatterings, may provide information about the space-time behaviour of the production process. Therefore the main goals of these investigations are related with the attempts to study the space-time process of hadronization of coloured quarks and gluons produced at the initial stage of an interaction to white final state particles and to clarify the influence of composite quark-gluon structure of both the projectile and target on features of the production mechanisms. Since in both the initial and final states of these reactions the authors have strongly interacting multiparticle systems, it is of importance to study the collective properties of these systems. The questions to the point are: what is the degree of collectivization of particles newly produced in collisions with nuclei and what is the influence of the collective nature of a nucleus itself on the production mechanisms, in particular, what are the manifestations of possible multinucleon (multiquark) configurations in nuclei? It is obvious that the reductability of, say, hadron-nucleus (hA) interaction to hadron-nucleon (hN) collisions is directly related to the above problems. Due to time limitations the author discusses here only a few aspects of low p/sub t/ hA interactions which in his opinion are of importance for better understanding of general regularities of collisions with nuclei and for further investigations of the above problems

  12. Neutron-Rich Silver Isotopes Produced by a Chemically Selective Laser Ion-Source: Test of the R-Process " Waiting-Point " Concept

    CERN Multimedia

    2002-01-01

    The r-process is an important nucleosynthesis mechanism for several reasons: \\begin{enumerate} \\item It is crucial to an understanding of about half of the A>60 elemental composition of the Galaxy; \\item It is the mechanism that forms the long-lived Th-U-Pu nuclear chronometers which are used for cosmochronolgy; \\item It provides an important probe for the temperature (T$ _{9} $)-neutron density ($n_{n}$) conditions in explosive events; and last but not least \\item It may serve to provide useful clues to and constraints upon the nuclear properties of very neutron-rich heavy nuclei. \\end{enumerate} \\\\ \\\\With regard to nuclear-physics data, of particular interest are the T$ _{1/2} $ and P$_{n-} $ values of certain$\\,$ "waiting-point"$\\,$ isotopes in the regions of the A $ \\approx $ 80 and 130. r-abundance peaks. Previous studies of $^{130}_{\\phantom{1}48}$Cd$_{82}$ and $^{79}_{29}$Cu$_{50}$. $\\beta$-decay properties at ISOLDE using a hot plasma ion source were strongly complicated by isobar and molecular-ion c...

  13. Study of the N=28 shell closure by one neutron transfer reaction: astrophysical application and {beta}-{gamma} spectroscopy of neutron rich nuclei around N=32/34 and N=40; Etude de la fermeture de couche N=28 autour du noyau {sub 18}{sup 46}Ar{sub 28} par reaction de transfert d'un neutron: application a l'astrophysique et Spectroscopie {beta}-{gamma} de noyaux riches en neutrons de N=32/34 et N=40

    Energy Technology Data Exchange (ETDEWEB)

    Gaudefroy, L

    2005-09-15

    The study of the N=28 shell closure has been presented as well as its astrophysical implications. Moreover the structure of neutron rich nuclei around N=32/34 and 40 was studied. The N=28 shell closure has been studied trough the one neutron transfer reaction on {sup 44,46}Ar nuclei. Excitation energies of states in {sup 45,47}Ar nuclei have been obtained, as well as their angular momenta and spectroscopic factors. These results were used to show that N=28 is still a good magic number in the argon isotopic chain. We interpreted the evolution of the spin-orbit partner gaps in terms of the tensor monopolar proton-neutron interaction. Thanks to this latter, we showed it is not necessary to summon up a reduction of the intensity of the spin-orbit force in order to explain this evolution in N=29 isotopes from calcium to argon chains. The neutron capture rates on {sup 44,46}Ar have been determined thanks to the results of the transfer reaction. Their influence on the nucleosynthesis of {sup 46,48}Ca was studied. We proposed stellar conditions to account for the abnormal isotopic ratio observed in the Allende meteorite concerning {sup 46,48}Ca isotopes. The beta decay and gamma spectroscopy of neutron rich nuclei in the scandium to cobalt region has been studied. We showed that beta decay process is dominated by the {nu}f{sub 5/2} {yields} {pi}f{sub 7/2} Gamow-Teller transition. Moreover, we demonstrated that the {nu}g{sub 9/2} hinders this process in the studied nuclei, and influences their structure, by implying the existence of isomers. Our results show that N=34 is not a magic number in the titanium chain and the superior ones. (author)

  14. Masterpieces unmasked: New high-resolution infrared cameras produce rich, detailed images of artwork, and create new controversies

    CERN Document Server

    Marshall, J

    2002-01-01

    Luca Pezzati is a physicist who heads a group called Art Diagnostics, which is a part of the Opificio delle Pietre Dure, an institute devoted to the research and conservation of artworks in Italy. Pezzati and his group use high-resolution infrared scanning device to produce colour images of what lies below the surface of paintings. Their scanner is able to produce the best-known quality of images without harming the painting under examination (1 page).

  15. Theoretical study on production of heavy neutron-rich isotopes around the N=126 shell closure in radioactive beam induced transfer reactions

    Directory of Open Access Journals (Sweden)

    Long Zhu

    2017-04-01

    Full Text Available In order to produce more unknown neutron-rich nuclei around N=126, the transfer reactions 136Xe + 198Pt, 136–144Xe + 208Pb, and 132Sn + 208Pb are investigated within the framework of the dinuclear system (DNS model. The influence of neutron excess of projectile on production cross sections of target-like products is studied through the reactions 136,144Xe + 208Pb. We find that the radioactive projectile 144Xe with much larger neutron excess is favorable to produce neutron-rich nuclei with charge number less than the target rather than produce transtarget nuclei. The incident energy dependence of yield distributions of fragments in the reaction 132Sn + 208Pb are also studied. The production cross sections of neutron-rich nuclei with Z=72–77 are predicted in the reactions 136–144Xe + 208Pb and 132Sn + 208Pb. It is noticed that the production cross sections of unknown neutron-rich nuclei in the reaction 144Xe + 208Pb are at least two orders of magnitude larger than those in the reaction 136Xe + 208Pb. The radioactive beam induced transfer reactions 139,144Xe + 208Pb, considering beam intensities proposed in SPIRAL2 (Production System of Radioactive Ion and Acceleration On-Line project as well, for production of neutron-rich nuclei around the N=126 shell closure are investigated for the first time. It is found that, in comparison to the stable beam 136Xe, the radioactive beam 144Xe shows great advantages for producing neutron-rich nuclei with N=126 and the advantages get more obvious for producing nuclei with less charge number.

  16. Properties and decay modes of hot nuclei produced in the reaction: 36Ar on 58Ni and detected with INDRA device

    International Nuclear Information System (INIS)

    Nalpas, L.

    1997-01-01

    Hot nuclei are formed in heavy ion collisions covering the Fermi energy domain. According to the excitation energy deposited into these nuclei, several de-excitation processes can be observed, in particular the emission of complex fragments (Z ≥ 3) which remains poorly understood. The GANIL facility offers the possibility to cover the excitation function for the Ar on Ni reaction over a broad energy range from 32 to 95 MeV/u where the hot nuclei evolve from classical 'evaporation' to complete 'vaporization' into light particles (neutrons, isotopes of H, He). The study of reaction mechanisms shows that from peripheral to central collisions the total cross section is dominated by binary dissipative collisions. Both partners coming from well-characterized events with the INDRA detector are reconstructed using the 'Minimum Spanning Tree' method. Thus excitation energy up to 20 MeV/A are reached in the most violent collisions at the highest bombarding energy. The deposited energy is not shared in the mass ratio between the quasi-projectile and the quasi-target, the quasi-projectile being hotter. For total excitation energies ranging roughly from 2 to 8 MeV/A, the proportion of 'multifragmentation' events increases to reach a plateau at about 10 MeV/A due to the rising probability to have complete 'vaporization' of the system above 8 MeV/A. The steady increase of the temperature extracted from the double isotopic He-Li ratios with excitation energy for the quasi-projectile suggests a progressive evolution of the de-excitation processes as predicted by statistical models. No signal of first order liquid-gas phase transition is seen in our data. (author)

  17. Surface energy of very neutron rich nuclei

    CERN Document Server

    Von Groote, H

    1976-01-01

    For a microscopic model calculation of the nuclear surface-energy coefficient sigma the surface energy is defined as the energy loss of an uncharged, semiinfinite (inhomogeneous) two-component system compared to an infinite (homogeneous) system with the same particle asymmetry delta . Using the Thomas-Fermi model the calculations are performed for a series of systems with increasing delta , starting from symmetric matter ( delta =0) and extending beyond the drip line of the neutrons, until the system undergoes a phase transition to a homogeneous system. The results for the surface energy as well as for the neutron skin and for the surface diffuseness are compared to the macroscopic approach of the Droplet Model (DM), which turns out to be a good approximation for small asymmetries typical for the region of the valley of beta -stability. For larger asymmetries, close to the drip lines, terms of higher order than contained in the DM approach are no longer negligible. Beyond the drip lines the pressure of the ou...

  18. Decay analysis of compound nuclei formed in reactions with exotic neutron-rich 9Li projectile and the synthesis of 217At* within the dynamical cluster-decay model

    Science.gov (United States)

    Kaur, Arshdeep; Kaushal, Pooja; Hemdeep; Gupta, Raj K.

    2018-01-01

    The decay of various compound nuclei formed via exotic neutron-rich 9Li projectile is studied within the dynamical cluster-decay model (DCM). Following the earlier work of one of us (RKG) and collaborators (M. Kaur et al. (2015) [1]), for an empirically fixed neck-length parameter ΔRemp, the only parameter in the DCM, at a given incident laboratory energy ELab, we are able to fit almost exactly the (total) fusion cross section σfus =∑x=16σxn for 9Li projectile on 208Pb and other targets, with σfus depending strongly on the target mass of the most abundant isotope and its (magic) shell structure. This result shows the predictable nature of the DCM. The neck-length parameter ΔRemp is fixed empirically for the decay of 217At* formed in 9Li + 208Pb reaction at a fixed laboratory energy ELab, and then the total fusion cross section σfus calculated for all other reactions using 9Li as a projectile on different targets. Apparently, this procedure could be used to predict σfus for 9Li-induced reactions where experimental data are not available. Furthermore, optimum choice of "cold" target-projectile combinations, forming "hot" compact configurations, are predicted for the synthesis of compound nucleus 217At* with 8Li + 209Pb as one of the target-projectile combination, or another (t , p) combination 48Ca + 169Tb, with a doubly magic 48Ca, as the best possibility.

  19. Study of neutron-rich nuclei structure around the N=28 shell closure using the in-beam gamma spectroscopy technique; Etude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, B

    2007-10-15

    For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, {sup 42}Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in {sup 42}Si, combined with the observation of {sup 38,40}Si and the spectroscopy of {sup 41,43}P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure. (author)

  20. Observation of the new neutron-rich nuclei 29F, 35,36Mg, 38,39Al, 40,41Si, 43,44P, 45,46,47S, 46,47,48,49Cl and 49,50,51Ar by means of a 55 MeV/u 48Ca beam

    International Nuclear Information System (INIS)

    Guillemaud-Mueller, D.; Anne, R.; Penionzhkevich, Yu.Eh.

    1988-01-01

    Using magnetic separation and identification through time of flight and ΔE,E measurements, the new neutron-rich nuclei, 29 F, 35,36 Mg, 38,39 Al, 40,41 Si, 43,44 P, 45,46,47 S, 46,47,48,49 Cl, 49,50,51 Ar have been observed from interactions of 48 Ca beam of 55 MeV/u with tantalum targets

  1. The influence of heavy metals on the polymorphs of dicalcium silicate in the belite-rich clinkers produced from electroplating sludge.

    Science.gov (United States)

    Chen, Ying-Liang; Shih, Pai-Haung; Chiang, Li-Choung; Chang, Yi-Kuo; Lu, Hsing-Cheng; Chang, Juu-En

    2009-10-15

    The purpose of this study is to utilize an electroplating sludge for belite-rich clinker production and to observe the influence of heavy metals on the polymorphs of dicalcium silicate (C(2)S). Belite-rich clinkers prepared with 0.5-2% of NiO, ZnO, CuO, and Cr(2)O(3) were used to investigate the individual effects of the heavy metals in question. The Reference Intensity Ratio (RIR) method was employed to determine the weight fractions of gamma-C(2)S and beta-C(2)S in the clinkers, and their microstructures were examined by the transmission electron microscopy (TEM). The results showed that nickel, zinc, and chromium have positive effects on beta-C(2)S stabilization (Cr(3+)>Ni(2+)>Zn(2+)), whereas copper has a negative effect. The addition of up to 10% electroplating sludge did not have any negative influence on the formation of C(2)S. It was observed that gamma-C(2)S decreased while beta-C(2)S increased with a rise in the addition of the electroplating sludge. Moreover, nickel and chromium mainly contributed to stabilizing beta-C(2)S in the belite-rich clinkers produced from the electroplating sludge.

  2. Study of the neutron-rich nuclei with N=21, sup 3 sup 5 Si and sup 3 sup 3 Mg, by beta decay of sup 3 sup 5 Al and sup 3 sup 3 Na

    CERN Document Server

    Nummela, S; Caurier, E; Courtin, S; Dessagne, P; Holmlund, E; Jokinen, A; Knipper, A; Le Scornet, G; Mieh, C; Nowacki, F; Lyapin, L G; Oinonen, M; Poirier, E; Radivojevic, Z; Ramdhane, M; Trzaska, W H; Walter, G; Äystö, J

    2002-01-01

    The first information on the level structure of the N=21 nuclei, sup 3 sup 5 Si and sup 3 sup 3 Mg, has been obtained by the beta decay study of sup 3 sup 5 Al and sup 3 sup 3 Na, produced by fragmentation of an UC target with 1.4 GeV protons at CERN/ISOLDE. The experimental technique involved beta-gamma, beta-gamma-gamma, and beta-n-gamma coincidences, neutron spectra being obtained by time of flight measurements. Gamma detection was made either using large Ge counters or small BaF sub 2 scintillators (for lifetime measurements). In the case of the sup 3 sup 5 Al decay, (T sub 1 sub / sub 2 =41.6(2.2) ms), a simple structure has been found for the level scheme of sup 3 sup 5 Si (Z=14, N=21) which has been interpreted with the level sequence : 7/2 sup - , 3/2 sup - and 3/2 sup + corresponding respectively to the ground state and the states at 910 and 974 keV. The life-time of the 974 keV [T sub 1 sub / sub 2 =5.9(6) ns] is found consistent with the proposed level scheme and multipolarities. The investigation ...

  3. Primordial nuclei

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The recent detection of intergalactic helium by NASA's Astro-2 mission backs up two earlier measurements by ESA and the University of California, San Diego, using instruments aboard the Hubble Space Telescope. Taken together, these results give strong evidence that this helium is primordial, confirming a key prediction of the Big Bang theory. The amount of helium the results imply could also account for some of the Universe's invisible dark matter - material which affects galactic motion but is otherwise undetectable. According to theory, helium nuclei formed at around 100 seconds after the Big Bang, but the amount of helium depended on even earlier events. Initially, protons turned into neutrons with the same probability that neutrons turned into protons. But after about one second, the Universe had cooled down enough for the weak interaction to freeze out. Neutrons continued to decay into the slightly lighter protons, whilst the opposite reaction became much more scarce. At around 100 seconds, thermonuclear fusion reactions could begin, and all the neutrons that were left became absorbed into helium nuclei, leaving the remaining protons locked up in hydrogen. The ratio of helium to hydrogen was therefore determined by events occurring when the Universe was just one second old. Standard models of primordial nucleosynthesis fix this ratio at slightly less than 2 5% by mass. All heavier elements were cooked up much later in the stars, and amount to less than 1 % of the Universe's mass. These predictions have been borne out remarkably well by observation, although proof of the primordial origins of hydrogen and helium has remained elusive until now. Big Bang nucleosynthesis goes on to estimate that primordial baryonic matter in the form of light nuclei could account for around 10% of the Universe's dark matter. All three recent measurements used the same technique of looking at distant quasars, some of the most luminous objects in the Universe, to

  4. Improvement in ductility of high strength polycrystalline Ni-rich Ni{sub 3}Al alloy produced by EB-PVD

    Energy Technology Data Exchange (ETDEWEB)

    Sun, J.Y.; Pei, Y.L.; Li, S.S.; Zhang, H.; Gong, S.K., E-mail: gongsk@buaa.edu.cn

    2014-11-25

    Highlights: • High strength and high ductility of polycrystalline Ni-rich Ni{sub 3}Al alloy sheets were produced. • The elongation could be enhanced from ∼0.5% to ∼14.6% by microstructural control. • The fracture strength (∼820 MPa) was enhanced by the precipitation strengthening. • This work provides a general processing for repairing the worn single crystal blades. - Abstract: A 300 μm Ni-rich Ni{sub 3}Al sheet was produced by electron beam physical vapor deposition (EB-PVD) and followed by different heat treatments to obtain fine γ′/γ two-phase structures with large elongation. Tensile testing was performed at room-temperature, and the corresponding mechanisms were investigated in detail. Results indicated that the as-deposited Ni{sub 3}Al alloy exhibited non-equilibrium directional columnar crystal, and transited to equiaxed crystal with uniformly distributed tough γ phase after heat treatment. Meanwhile, the fracture mechanism transited from brittleness to a mixture of ductility and brittleness modes. With an appropriate heat treatment, high strength (ultimate tensile strength obtained 828 MPa) and high ductility (elongation obtained 14.6%) Ni{sub 3}Al alloy has been achieved, which was due to the mesh network microstructure. A series of transmission electron microscope (TEM) characterizations confirmed that the increasing flow stress of Ni{sub 3}Al alloy was attributed to the cubical secondary γ′ phase precipitates (25–50 nm) within the γ phase. This work provides a potential strategy for repairing the worn tip of single crystal engine blades using Ni-rich Ni{sub 3}Al alloy by EB-PVD.

  5. Nuclei in a neutron star

    International Nuclear Information System (INIS)

    Oyamatsu, K.; Yamada, M.

    1994-01-01

    We report on the recent progress in understanding the matter in the crust of a neutron star. For nuclides in the outer crust, recently measured masses of neutron-rich nuclei enable us to determine more accurately the stable nuclide as a function of the matter density. In the inner crust, the compressible liquid-drop model predicts successive change of the nuclear shape, from sphere to cylinder, slab, cylindrical hole and spherical hole at densities just before the transition to uniform matter. In order to go beyond the liquiddrop model, we performed the Thomas-Fermi calculation paying special attention to the surface diffuseness, and have recently calculated the shell energies of the non-spherical nuclei. We have found from these studies that all these non-spherical nuclei exist stably in the above order even if we include the surface diffuseness and shell energies. (author)

  6. Experimental and theoretical studies of the yields of residual product nuclei produced in thin Pb and Bi targets irradiated by 40 - 2600 MeV protons

    International Nuclear Information System (INIS)

    Titarenko, Yu. E.; Batyaev, V.F.; Karpikhin, E.I.; Zhivun, V.M.; Ignatyuk, A.V.; Lunev, V.P.; Titarenko, N.N.; Shubin, Yu.N.; Barashenkov, V.S.

    2009-10-01

    The Project is aimed at experimental determining and computer-aided theoretical simulating the independent and cumulative yields of residual radioactive product nuclei in high-energy protonirradiated thin targets made of high-isotopic and natural lead ( 206 Pb, 207 Pb, 208 PB, natPb) and bismuth ( 209 Bi) that are the most probable choice to be the target materials in the acceleratordriven (hybrid) systems (ADS) coupled to a high-current proton accelerator. The yields of residual product nuclei are of great importance when estimating such basic radiation-technology characteristics of the hybrid facility targets as the total target activity, the target 'poisoning', the buildup of long-lived nuclides, the α-activity, the content of low-pressure evaporated nuclides (Hg), the content of the chemically-active nuclides that drastically spoil the corrosion resistance of the facility structure materials, etc. In view of the above, the radioactive product nuclide yields from targets materials were experimentally determined using the ITEP U-10 proton accelerator in 55 measurement runs using the monoisotopic and natural lead ( 206 Pb, 207 Pb, 208 PB, natPb) and bismuth ( 209 Bi) targets within the proton energy range fractionated minutely, namely at 0.04, 0.07, 0.10, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV to cover the entire range of the internuclear hadron cascading. As a result, 5972 cumulative and independent yields of residual radioactive product nuclei, whose lifetimes range from 8 minutes to 32 years, have been measured. Besides, the cross sections for the 27 Al(p,x) 24 Na and 27 Al(p,x)7Be monitor reactions have been measured at the same proton energies together with the 27 Al(n,p) 27 Mg reaction rate that characterizes the neutron background contributions in each experiment. The experimental nuclide yields are determined by the direct γ-spectrometry method. The γ-spectrometer resolution is 1.8 keV in the 1332 keV 60 Co γ-line. The experimental γ-spectra are processed by

  7. Heavy ions as probes of nuclei far from stability

    International Nuclear Information System (INIS)

    Moltz, D.M.; Nitschke, J.M.; Wilmarth, P.A.; Toth, K.S.

    1989-01-01

    Nuclei located far from stability provide us with an opportunity for studying nuclear matter existing under unusual conditions. In these regions of instability, radioactive decay becomes the predominant technique by which one can obtain structure information. We have been involved in the investigation of nuclear properties of nuclei close to the proton drip line. In our explorations we have utilized heavy-ion fusion, followed by particle evaporation, to produce the extremely neutron-deficient nuclei of interest. In our studies, single-particle states near the 82-neutron shell, populated in the β decay of short-lived nuclides, have been examined and their excitation energies determined. Numerous new isotopes, isomers, and β-delayed-proton and α-particle emitters have been discovered. This contribution will discuss our particle-decay investigations. These decay modes provide us with a convenient means of discovering new isotopes whose identification opens the way for further, more extensive explorations. Also, particle-decay energies in many instances can be used to determine mass differences between parent and daughter ground states. Such measurements are therefore used to test mass formulae and to obtain estimates of masses for proton rich nuclei. 19 refs., 13 figs

  8. Production of actinide nuclei by multi-nucleon transfer

    Energy Technology Data Exchange (ETDEWEB)

    Lauritsen, T.; Ahmad, I.; Carpenter, M.P. [and others

    1995-08-01

    Multi-nucleon transfers have increasingly allowed us to reach parts of the nuclear chart where regular compound nuclear reactions are prohibited. The interesting region of Ra and Rn, where a rich tapestry of nuclear structure manifests itself, is now accessible using this technique of deep inelastic scattering. In particular, these nuclei are predicted to lie at the onset of octupole deformation and the region is rich in examples of shape coexistence. There are several theoretical predictions of nuclear structure of these nuclei that have not been experimentally tested. Moreover, there is serious disagreement among these theories. We used a beam of {sup 136}Xe at 720 MeV from ATLAS on a target of {sup 232}Th to produce a range of Rn isotopes, with a mass from 220 to 224, and Ra isotopes with masses greater than 222. The beam energy, target and beam were selected carefully to enhance the cross-section for production of these nuclei and reduce the Doppler broadening of the gamma rays that were observed in the Argonne Notre Dame gamma-ray facility. The 12 germanium detectors of this array allowed the observation of gamma-gamma coincidences. The inner ball of 50 BGO detectors allowed us to record the multiplicity and sum-energy information for each event. The latter should permit us to determine the entry region in the products of the transfer reaction. We had four successful days of beam-time, when we collected in excess of 8 x 10{sup 7} events. Data analysis is in progress at the University of Liverpool. A complete set of spectroscopic information on the yrast structure of the many nuclei produced in this reaction is being extracted.

  9. Experiments with stored relativistic exotic nuclei

    International Nuclear Information System (INIS)

    Klepper, O.; Attallah, F.; Beckert, K.; Bosch, F.; Dolinskiy, A.; Eickhoff, H.; Franczak, B.; Franzke, B.; Geissel, H.; Hausmann, M.; Hellstroem, M.; Herfurth, F.; Kluge, H.-J.; Kozhuharov, C.; Muenzenberg, G.; Nolden, F.; Quint, W.; Tradon, T.; Reich, H.; Scheidenberger, C.; Schlitt, B.; Steck, M.; Suemmerer, K.; Vermeeren, L.; Winkler, M.; Winkler, Th.; Falch, M.; Kerscher, Th.; Loebner, K.E.G.; Fujita, Y.; Novikov, Yu.; Patyk, Z.; Stadlmann, J.; Wollnik, H.

    1999-01-01

    Beams of relativistic exotic nuclei were produced, separated and investigated with the combination of the fragment separator FRS and the storage ring ESR. The following experiments are presented: 1) Direct mass measurements of relativistic nickel and bismuth projectile fragments were performed using Schottky spectrometry. Applying electron cooling, the relative velocity spread of the circulating secondary nuclear beams of low intensity was reduced to below 10 -6 . The achieved mass resolving power of m/Δm = 6.5·10 5 (FWHM) in recent measurements represents an improvement by a factor of two compared to authors' previous experiments. The previously unknown masses of more than 100 proton-rich isotopes have been measured in the range of 54≤Z≤84. The results are compared with mass models and estimated values based on extrapolations of experimental values. 2) Exotic nuclei with half-lives shorter than the time required for electron cooling can be investigated by time-of-flight measurements with the ESR being operated in the isochronous mode. This novel experimental technique has been successfully applied in a first measurement with nickel fragments. A mass resolving power of m/Δm = 1.5·10 5 (FWHM) was achieved in this mode of operation. 3) Nuclear half-lives of stored and cooled bare projectile fragments have been measured to study the influence of the ionic charge state on the beta-decay probability

  10. Elementary excitations in nuclei

    International Nuclear Information System (INIS)

    Lemmer, R.H.

    1987-01-01

    The role of elementary quasi-particle and quasi-hole excitations is reviewed in connection with the analysis of data involving high-lying nuclear states. This article includes discussions on: (i) single quasi-hole excitations in pick-up reactions, (ii) the formation of single quasi-hole and quasi-particle excitations (in different nuclei) during transfer reactions, followed by (iii) quasi-particle quasi-hole excitations in the same nucleus that are produced by photon absorption. Finally, the question of photon absorption in the vicinity of the elementary Δ resonance is discussed, where nucleonic as well as nuclear degrees of freedom can be excited

  11. PEMANFAATAN MINYAK SAWIT MERAH DALAM PEMBUATANBISKUIT KACANG KAYA BETA KAROTEN [Utilization of Red Palm Oil To Produce BetaCarotene-Rich Nuts Biscuit

    Directory of Open Access Journals (Sweden)

    Robiyansyah Robiyansyah

    2017-03-01

    Full Text Available The purpose of this research was to get formulation of red palm oil and cooking oil to produce nuts biscuits with the best organoleptic properties. The formula consisted of red palm oil and cooking oil mixture with 6 comparisons: (0:100, (20:80, (40:60, (60:40, (80:20 and (100:0. These formula were then used as basis to produce nuts biscuits. Observation was done on the organoleptic properties (aroma, texture, taste and color for all biscuits for all samples, while  proximates test (water, fat,protein,ash content and betacarotene content were done only for the best formulation. The data were descriptively analyzed and presented in tables and graphs. The best organoleptic properties of these betacarotene rich nuts biscuits was formulation of 20:80. This biscuits had water content 1,42%, ash content 1,21%, fat content 32,60%, protein content 12,59%, and the total of beta carotene 347,15 ppm, with the less normal for aroma (4,55, less crunchy for the texture (4,40, distinctive flavor beans for the taste (4,28, and yellowish for the color (4,50. Keywords: β-carotene, nuts biscuits,red palm oil.

  12. Synthesis and study of neutron-rich nuclides

    International Nuclear Information System (INIS)

    Luo Yixiao

    1995-01-01

    During the past few years our understanding of the decay properties and nuclear structure has been extended in a systematic fashion for the neutron-rich nuclei. This review will first sketch the production and identification of the neutron-rich nuclei throughout the whole mass region, and will then discuss the impressive progress in the studies of the exotic decay properties and nuclear structure of neutron-rich nuclei. Their astrophysical implications will also be outlined

  13. High spin spectroscopy of near spherical nuclei: Role of intruder orbitals

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, S.; Bhattacharjee, T.; Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064 (India); Chanda, S. [Fakir Chand College, Diamond Herbour, West Bengal (India); Banerjee, D.; Das, S. K.; Guin, R. [Radiochemistry Division, Variable Energy Cyclotron Centre, BARC, Kolkata - 700064 (India); Gupta, S. Das [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Saha Institute of Nuclear Physics, Kolkata-700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata - 700064, India and Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

    2014-08-14

    High spin states of nuclei in the vicinity of neutron shell closure N = 82 and proton shell closure Z = 82 have been studied using the Clovere Ge detectors of Indian National Gamma Array. The shape driving effects of proton and neutron unique parity intruder orbitals for the structure of nuclei around the above shell closures have been investigated using light and heavy ion beams. Lifetime measurements of excited states in {sup 139}Pr have been done using pulsed-beam-γ coincidence technique. The prompt spectroscopy of {sup 207}Rn has been extended beyond the 181μs 13/2{sup +} isomer. Neutron-rich nuclei around {sup 132}Sn have been produced from proton induced fission of {sup 235}U and lifetime measurement of low-lying states of odd-odd {sup 132}I have been performed from offline decay.

  14. Microscopic study of proton emission from heavy nuclei

    International Nuclear Information System (INIS)

    Sahu, B.B.; Patra, S.K.; Agarwalla, S.K.

    2011-01-01

    In recent years many theoretical calculations have been employed to explain the observed lifetimes of proton radioactivity and alpha decay processes in the region of proton rich nuclei. These data are very promising for the analysis of possible irregularities in the structure of these proton-rich nuclei. They are also of great interest in rapid proton capture processes. Some new results for proton radioactivity in this region of proton-rich nuclei have indicated that the proton emission mode is rather competitive with the alpha decay one. In the energy domain of radioactivity, proton can be considered as a point charge having highest probability of being present in the parent nucleus

  15. High-spin excitations of atomic nuclei

    International Nuclear Information System (INIS)

    Xu Furong; National Laboratory of Heavy Ion Physics, Lanzhou; Chinese Academy of Sciences, Beijing

    2004-01-01

    The authors used the cranking shell model to investigate the high-spin motions and structures of atomic nuclei. The authors focus the collective rotations of the A∼50, 80 and 110 nuclei. The A∼50 calculations show complicated g spectroscopy, which can have significant vibration effects. The A≅80 N≅Z nuclei show rich shape coexistence with prolate and oblate rotational bands. The A≅110 nuclei near the r-process path can have well-deformed oblate shapes that become yrast and more stable with increasing rotational frequency. As another important investigation, the authors used the configuration-constrained adiabatic method to calculate the multi-quasiparticle high-K states in the A∼130, 180 and superheavy regions. The calculations show significant shape polarizations due to quasi-particle excitations for soft nuclei, which should be considered in the investigations of high-K states. The authors predicted some important high-K isomers, e.g., the 8 - isomers in the unstable nuclei of 140 Dy and 188 Pb, which have been confirmed in experiments. In superheavy nuclei, our calculations show systematic existence of high-K states. The high-K excitations can increase the productions of synthesis and the survival probabilities of superheavy nuclei. (authors)

  16. Electron-capture Rates for pf-shell Nuclei in Stellar Environments and Nucleosynthesis

    Science.gov (United States)

    Suzuki, Toshio; Honma, Michio; Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Hidakai, Jun; Otsuka, Takaharu

    Gamow-Teller strengths in pf-shell nuclei obtained by a new shell-model Hamltonian, GXPF1J, are used to evaluate electron-capture rates in pf-shell nuclei at stellar environments. The nuclear weak rates with GXPF1J, which are generally smaller than previous evaluations for proton-rich nuclei, are applied to nucleosynthesis in type Ia supernova explosions. The updated rates are found to lead to less production of neutron-rich nuclei such as 58Ni and 54Cr, thus toward a solution of the problem of over-production of neutron-rich isotopes of iron-group nuclei compared to the solar abundance.

  17. Exotic Nuclei Arena in JHP

    International Nuclear Information System (INIS)

    Nomura, T.

    1991-12-01

    The Exotic Nuclei Arena planned in Japanese Hadron Project aims to accelerate various unstable nuclei produced in 1-GeV proton-induced reactions up to 6.5 MeV/u by means of heavy-ion linacs. The present status of research and development for the Earena is briefly reported. The construction of the prototype facility to accelerate unstable beams up to 0.8 MeV/u is planned in 1992-94, in which the existing cyclotron in INS is used as the primary accelerator. (author)

  18. Improved mechanical properties of Ni-rich Ni3Al coatings produced by EB-PVD for repairing single crystal blades

    Institute of Scientific and Technical Information of China (English)

    Jing-Yong Sun; Yan-Ling Pei; Shu-Suo Li; Hu Zhang; Sheng-Kai Gong

    2017-01-01

    Active control of turbine blade tip clearance for aircraft engine continues to be a concern in engine operation,because turbine blades are subjected to wear and therefore cause an increasing tip clearance between the rotating blades and the shroud and also reduce the engine efficiency.In this work,a Ni-rich Ni3Al coating with γ'/γtwo-phase microstructure was deposited by electron beam physical vapor deposition (EB-PVD),which worked as repairing the worn blade tips of single crystal blades.Nb molten pool was used to increase the molten pool temperature and thus to enhance the deposition rate.The microstructures and mechanical properties can be modified by the deposition temperatures and the following heat treatments.All coatings consist of γ'and γ phases.At deposition temperature of 600 ℃,a dense microstructure can be achieved to produce a coating with grain size of ~ 1 μm and microhardness of ~HV 477.After being heated for 4 h at a temperature of 1,100 ℃,the coatings have a more uniform microstructure,and microhardness maintains at a high level of ~ HV 292.Effect of Hf and Zr on EB-PVD Ni3Al repair coating will be further investigated.

  19. Exotic nuclei in self-consistent mean-field models

    International Nuclear Information System (INIS)

    Bender, M.; Rutz, K.; Buervenich, T.; Reinhard, P.-G.; Maruhn, J. A.; Greiner, W.

    1999-01-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei with emphasis on neutron-rich tin isotopes and superheavy nuclei. (c) 1999 American Institute of Physics

  20. Halo nuclei studied by relativistic mean-field approach

    International Nuclear Information System (INIS)

    Gmuca, S.

    1997-01-01

    Density distributions of light neutron-rich nuclei are studied by using the relativistic mean-field approach. The effective interaction which parameterizes the recent Dirac-Brueckner-Hartree-Fock calculations of nuclear matter is used. The results are discussed and compared with the experimental observations with special reference to the neutron halo in the drip-line nuclei. (author)

  1. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  2. Synthesis and study of neutron-rich nuclides

    International Nuclear Information System (INIS)

    Luo, Y.X.

    1995-01-01

    During the past few years our understanding of the decay properties and nuclear structure has been extended in a systematic fashion for the neutron-rich nuclei. This review will discuss the impressive progress in the studies of the exotic decay properties and nuclear structure of n-rich nuclei. Their astrophysical implications will also be outlined. ((orig.))

  3. Radii of nuclei off stability

    International Nuclear Information System (INIS)

    Sugimoto, Kenzo

    1982-01-01

    An experiment is proposed to determine systematically the radii of the nuclei produced through the projectile fragmentation process in high energy heavy-ion collision. The measurement of total reaction cross section using the projectile fragments of a single nuclide on a target give information about nuclear radii. The production cross section of the fragments is appreciable for many nuclides. Therefore, it is possible to map systematically the reaction radii of the nuclei which can be produced as the projectile fragments. In an experiment using the projectile fragments as the incident beam, the cross section can be expressed as a function of the radii of a projectile and a target. An experiment with He-8 produced by the fragmentation of C-12 is proposed. The He-8 has four neutrons in the p-3/2 orbit outside the He-4 core. Proton and neutron distributions for He isotopes were calculated on the basis of the Hartree-Fock method. The information related to this kind of distribution can be obtained by the proposed experiment. The nuclear structure effect is seen in the nuclear radii of other unstable nuclei. The experimental examples of the isotope shift measurement and the excitation energy are presented. (Kato, T.)

  4. Nuclei and quantum worlds

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    2000-01-01

    This document gathers the slides and their commentaries that have been presented at the conference 'physics and fundamental questions' by P. Chomaz. The author reviews the different quantum aspects of nuclei: tunnel effect, symmetries, magic numbers, wave functions, size, shapes and deformations. The author shows that nuclei are quantum objects of great complexity, their structures are not yet well understood and the study of exotic nuclei will continue bringing valuable information

  5. Pairing correlations in nuclei

    International Nuclear Information System (INIS)

    Baba, C.V.K.

    1988-01-01

    There are many similarities between the properties of nucleons in nuclei and electrons in metals. In addition to the properties explainable in terms of independent particle motion, there are many important co-operative effects suggesting correlated motion. Pairing correlation which leads to superconductivity in metals and several important properties in nuclei , is an exmple of such correlations. An attempt has been made to review the effects of pairing correlations in nuclei. Recent indications of reduction in pairing correlations at high angular momenta is discussed. A comparision between pairing correlations in the cases of nuclei and electrons in metals is attempted. (author). 20 refs., 10 figs

  6. Fragmentation of relativistic nuclei

    International Nuclear Information System (INIS)

    Cork, B.

    1975-06-01

    Nuclei with energies of several GeV/n interact with hadrons and produce fragments that encompass the fields of nuclear physics, meson physics, and particle physics. Experimental results are now available to explore problems in nuclear physics such as the validity of the shell model to explain the momentum distribution of fragments, the contribution of giant dipole resonances to fragment production cross sections, the effective Coulomb barrier, and nuclear temperatures. A new approach to meson physics is possible by exploring the nucleon charge-exchange process. Particle physics problems are explored by measuring the energy and target dependence of isotope production cross sections, thus determining if limiting fragmentation and target factorization are valid, and measuring total cross sections to determine if the factorization relation, sigma/sub AB/ 2 = sigma/sub AA/ . sigma/sub BB/, is violated. Also, new experiments have been done to measure the angular distribution of fragments that could be explained as nuclear shock waves, and to explore for ultradense matter produced by very heavy ions incident on heavy atoms. (12 figures, 2 tables)

  7. High energy particle interactions with nuclei

    International Nuclear Information System (INIS)

    Czyz, W.

    1978-01-01

    The recent interest in multiparticle production processes on nuclei was triggered by re-discovering their 'enigmatic simplicity' which has been known to cosmic ray physicists for over 20 years: the mean multiplicity and angular distributions of relativistic secondaries produced on nuclei do not differ markedly from what emerges from p-p collisions. The author considers how such reactions may provide a way of obtaining details of hadron structure. (Auth.)

  8. Hot nuclei, limiting temperatures and excitation energies

    International Nuclear Information System (INIS)

    Peter, J.

    1986-09-01

    Hot fusion nuclei are produced in heavy ion collisions at intermediate energies (20-100 MeV/U). Information on the maximum excitation energy per nucleon -and temperatures- indicated by the experimental data is compared to the predictions of static and dynamical calculations. Temperatures around 5-6 MeV are reached and seem to be the limit of formation of thermally equilibrated fusion nuclei

  9. Laser Spectroscopy Studies in the Neutron-Rich Sn Region

    CERN Multimedia

    Obert, J

    2002-01-01

    We propose to use the powerful laser spectroscopy method to determine the magnetic moment $\\mu$ and the variation of the mean square charge radius ($\\delta\\,\\langle$r$_{c}^{2}\\,\\rangle$) for ground and long-lived isomeric states of the Sn isotopes from A=125 to the doubly-magic $^{132}$Sn isotope and beyond. For these neutron-rich Sn nuclei, numerous $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ curves have already been calculated and the predictions depend upon the effective interactions used. Therefore, a study of the effect of the shell closure N=82 on the $\\delta\\,\\langle$r$^{2}_{c}\\,\\rangle$ values in the Z=50 magic nuclei is of great interest, especially because $^{132}$Sn is located far from the stability valley. It will help to improve the parameters of the effective interactions and make them more suitable to predict the properties of exotic nuclei. \\\\ \\\\The neutron-rich Sn isotopes produced with an uranium carbide target, are ionized using either a hot plasma ion source or the resonant ionization laser ion ...

  10. Nuclei with exotic constituents

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu.

    1990-08-01

    We discuss various interesting features in the behavior of exotic constituents of nuclei such as hyperons and mesons, in particular, with emphases on the aspect of exotic halos which are formed in general by short-range repulsion and long-range attraction. Specifically, Λ and Σ hypernuclei and pionic nuclei are discussed. (author)

  11. Baryon resonances in nuclei

    International Nuclear Information System (INIS)

    Arenhoevel, H.

    1977-01-01

    The field of baryon resonances in nuclei is reviewed. Theoretical developments and experimental evidence as well are discussed. Special emphasis is laid on electromagnetic processes for the two nucleon system. Some aspects of real isobars in nuclei are touched upon. (orig.) [de

  12. Nuclei in high forms

    International Nuclear Information System (INIS)

    Szymanski, Z.; Berger, J.F.; Heenen, P.H.; Heyde, K.; Haas, B.; Janssens, R.; Paya, D.; Gogny, D.; Huber, G.; Bjoernholm, S.; Brack, M.

    1991-01-01

    The purpose of 1991 Joliot-Curie Summer School is to review the most advances in the understanding of the nuclei physics after the considerable progress in gamma spectroscopy. It covers the following topics: Highly and super-deformed nuclei, nuclear structures, mean-field approach and beyond, fission isomers, nuclear excitations with long lifetime and metal clusters

  13. Pair correlations in nuclei

    International Nuclear Information System (INIS)

    Shimizu, Yoshifumi

    2009-01-01

    Except for the closed shell nuclei, almost all nuclei are in the superconducting state at their ground states. This well-known pair correlation in nuclei causes various interesting phenomena. It is especially to be noted that the pair correlation becomes weak in the excited states of nuclei with high angular momentum, which leads to the pair phase transition to the normal state in the high spin limit. On the other hand, the pair correlation becomes stronger in the nuclei with lower nucleon density than in those with normal density. In the region of neutron halo or skin state of unstable nuclei, this phenomenon is expected to be further enhanced to be observed compared to the ground state of stable nuclei. An overview of those interesting aspects caused via the pair correlation is presented here in the sections titled 'pair correlations in ground states', pair correlations in high spin states' and 'pair correlations in unstable nuclei' focusing on the high spin state. (S. Funahashi)

  14. Investigation of the core-halo structure of the neutron-rich nuclei 6He and 8He by intermediate-energy elastic proton scattering at high momentum transfer

    International Nuclear Information System (INIS)

    Aksouh, F.

    2002-12-01

    The elastic proton scattering from the halo nuclei 6 He and 8 He was investigated in inverse kinematics at energies around 700 MeV/u with the aim to deduce the differential cross sections for the region of high momentum transfer, covering the first diffraction minimum. For this purpose, a liquid-hydrogen target was specially developed and used for the first time allowing to obtain low-background data as compared to commonly used targets made from C-H compounds. Previous data taken in the region of small momentum transfer were sensitive to the size and the peripheral shape of the total nuclear matter density distribution but not to the inner part. The present data allow for a more detailed insight in the structure of the alike core in 6,8 He through a better determination of the matter density distributions. Several density distributions calculated from different microscopic models were used to derive elastic scattering cross sections which are compared with the obtained data. (author)

  15. New neutron-rich isotopes in the scandium-to-nickel region, produced by fragmentation of a 500 MeV/u 86Kr beam

    International Nuclear Information System (INIS)

    Weber, M.; Geissel, H.; Keller, H.; Magel, A.; Muenzenberg, G.; Nickel, F.; Pfuetzner, M.; Piechaczek, A.; Roeckl, E.; Rykaczewski, K.; Schall, I.; Suemmerer, K.; Donzaud, C.; Guillemaud-Mueller, D.; Mueller, A.C.; Stephan, C.; Tassan-Got, L.; Dufour, J.P.; Pravikoff, M.; Grewe, A.; Voss, B.; Vieira, D.J.

    1991-10-01

    We have measured production cross-sections of the new neutron-rich isotopes 58 Ti, 61 V, 63 Cr, 66 Mn, 69 Fe, 71 Co and neighbouring isotopes that have been identified as projectile fragments from reactions between a 500 MeV/u 86 Kr beam and a beryllium target. The isotope identification was performed with the zero-degree magnetic spectrometer FRS at GSI, using in addition time-of-flight and energy-loss mesurements. The experimental production cross-sections for the new nuclides and neighbouring isotopes are compared with an empirical parameterization. The resulting prospects for reaching even more neutron-rich isotopes, such as the doubly-magic nuclide 78 Ni, are discussed. (orig.)

  16. Rich micronutrient fortification of locally produced infant food does not improve mental and motor development of Zambian infants: a randomised controlled trial

    Science.gov (United States)

    Manno, Daniela; Kowa, Priscilla K.; Bwalya, Hellen K.; Siame, Joshua; Grantham-McGregor, Sally; Baisley, Kathy; De Stavola, Bianca L.; Jaffar, Shabbar; Filteau, Suzanne

    2013-01-01

    It is uncertain whether multiple micronutrients benefit the mental and psychomotor development of young children in developing countries. We conducted a randomised double-blind controlled trial to evaluate the effect of a richly micronutrient-fortified v. a basal fortified porridge on mental and psychomotor development in Zambian infants. Infants (n 743) were randomised at age 6 months to receive either the richly fortified or the basal fortified infant food and were followed up until 18 months of age. All the infants were evaluated monthly for achievement of a series of developmental milestones. The Bayley scales of infant development II were administered to a subsample of 502 infants at 6, 12 and 18 months. Rich micronutrient fortification had no significant benefit on the following: (a) number of developmental milestones achieved (rate ratio at 12 months = 1·00; 95 % CI 0·96, 1·05; P=0·81, adjusted for sex, socio-economic status and maternal education, with similar results at 15 and 18 months); (b) ages of walking unsupported (hazard ratio (HR) 1·04; 95 % CI 0·88, 1·24; P=0·63, adjusted for the above covariates) and of speaking three or four clear words (HR 1·01; 95 % CI 0·84, 1·20; P=0·94, adjusted for the above covariates); (c) mental development index (MDI) and psychomotor development index (PDI) of the Bayley scales (scores difference adjusted for baseline scores, age at the assessment, sex, socio-economic status, maternal education, language, age and HIV status: MDI 0·3 (95 % CI −0·5, 1·1), P=0·43; PDI −0·1 (95 % CI −0·9, 0·7), P=0·78). In conclusion, the results do not support the hypothesis that rich micronutrient fortification improves Zambian infants’ mental and motor development. PMID:21733297

  17. K isomerism and collectivity in neutron-rich rare-earth isotopes.

    OpenAIRE

    Patel, Zena

    2016-01-01

    Neutron-rich rare-earth isotopes were produced by in-flight fission of 238U ions at the Radioactive Isotope Beam Factory (RIBF), RIKEN, Japan. In-flight fission of a heavy, high-intensity beam of 238U ions on a light target provides the cleanest secondary beams of neutron-rich nuclei in the rare-earth region of isotopes. In-flight fission is advantageous over other methods of nuclear production, as it allows for a secondary beam to be extracted, from which the beam species can be separated an...

  18. New results with stored exotic nuclei at relativistic energies

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, F. (Fritz); Boutin, D. (Daniel); Fastermann, T. (Thomas); Falch, M. (Markus); Franzke, B. (Bernhard); Hausmann, M. (Marc); Hellstrom, M. (Margarete); Kaza, E. (Evangelia); Kerscher, T. (Thomas); Klepper, O. (Otto); Kluge, H.-Jürgen; Kozhuharov, C. (Christophor); Kratz, K. L.; Litinov, S. A. (Sergei A); Lobner, G. K. E. (Gunther K. E.); Maier, L. (Ludwig); Matos, M. (Milan); Munzenberg, G. (Gottfried); Nolden, F. (Fritz); Novikov, Y. N. (Yuri N.); Ohtsubo, T. (Takashi); Ostrowski, A. (Alexander); Patyk, Z. (Zygmund); Pfeiffer, B.; Portillo, M. (Mauricio); Radon, T. P. (Torsten P.); Scheidenberger, C. (Christoph); Shishkin, V. (Vladimir); Stadlman, J. (Jens); Steck, M. (Markus); Vieira, D. J. (David J.); Weick, H. (Helmut); Winkler, M. (Martin); Wollnik, Hermann; Yamaguchi, T. (Takayuki)

    2004-01-01

    Recently, much progress has been made with stored exotic nuclei at relativistic velocities v/c = 0.7. Fragments of {sup 208}Pb and {sup 209}Bi projectiles and fission fragments from {sup 238}U ions have been produced, separated in flight with the fragment separator FRS, and injected into the storage-cooler ring ESR for precision measurements. Precise masses of neutron-deficient isotopes in the lead region have been measured with time-resolved Schottky Mass Spectrometry (SMS). A new isospin dependence of the pairing energy was observed due to the improved mass accuracy of typical 1.5 x 10{sup -7} (30 keV). New masses of short-lived neutron-rich fission fragments have been obtained with Isochronous Mass Spectrometry (IMS). An innovative field of spectroscopy has been opened up with lifetime measurements of stored bare and few-electron fragments after applying both stochastic and electron cooling.

  19. Superheavy nuclei: a relativistic mean field outlook

    International Nuclear Information System (INIS)

    Afanasjev, A.V.

    2006-01-01

    The analysis of quasi-particle spectra in the heaviest A∼250 nuclei with spectroscopic data provides an additional constraint for the choice of effective interaction for the description of superheavy nuclei. It strongly suggests that only the parametrizations which predict Z = 120 and N = 172 as shell closures are reliable for superheavy nuclei within the relativistic mean field theory. The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied. A large central depression produces large shell gaps at Z = 120 and N = 172. The shell gaps at Z = 126 and N = 184 are favoured by a flat density distribution in the central part of the nucleus. It is shown that approximate particle number projection (PNP) by means of the Lipkin-Nogami (LN) method removes pairing collapse seen at these gaps in the calculations without PNP

  20. Is the caloric curve a robust signal of the phase transition in hot nuclei?

    International Nuclear Information System (INIS)

    Vient, E.

    2016-01-01

    The richness of the data set, collected by the INDRA Collaboration during the last twenty years, enabled to build a set of caloric curves for nuclei of various sizes, by using, for the first time, a single experimental set-up and a single experimental protocol. We will therefore present the different caloric curves (E ∗ −T) obtained by a new calorimetry, for Quasi-Projectiles produced by symmetric or quasi symmetric reactions at different incident energies (Au+Au, Xe+Sn, Ni+Ni). For all these systems, a clear change of the de-excitation process of hot nuclei is observed but this one is neither a plateau nor a back-bending, but a sudden change of slope.

  1. Spectroscopical study of the yrast and yrare structure in far-from-stability nuclei; Etude spectroscopique de la structure yrast et yrare de noyaux loin de la stabilite

    Energy Technology Data Exchange (ETDEWEB)

    Hoellinger Fabien [Institut de Recherches Subatomiques, 23, Rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France)]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    1999-01-13

    The nuclear structure study of neutron-rich nuclei was realized with the EUROGAM II array in two different experiments. The first study consisted in the analysis of the product of spontaneous fission of {sup 248}Cm. Three neutron-rich cerium isotopes {sup 147,149,151}Ce were analyzed. A level scheme for {sup 151}Ce is presented for the first time. The yrast structure of the three nuclei does not show alternative parity bands as expected in this region of octupole deformations. We studied the rotational structure of the bands and this leads to suggest Nilsson configurations to some of them. The aim of this second experiment was the study of the nuclei {sup 99}Mo, {sup 101}Tc, {sup 103}Ru. The three nuclei are situated on the neutron-rich side of the nuclear chart and are produced as fission fragments of a heavy-ion induced reaction. Some bands are extended to higher spins and some new bands are observed. The structure of the rotational bands is interpreted by means of the Hartree-Fock-Bogolyubov model. A last experiment intended to study the structure of the proton-rich nucleus {sup 223}Pa has been achieved with the JURO+RITU array located at Jyvaeskylae (Finland). In this proton-rich actinide region, the nuclei develop octupole features around Z{approx_equal}88, N{approx_equal}132. The analysis of this experiment leads to the first assignment of gamma transitions to the {sup 223}Pa. (author) 91 refs., 78 figs., 16 tabs.

  2. Nucleons in nuclei, however

    International Nuclear Information System (INIS)

    Grange, P.; Mathiot, J.F.; Roy-Stephan, M.; Frascaria, R.; Gales, S.

    1990-01-01

    The topics presented at the 1989 Joliot-Curie Lectures are reported. Two main subjects were retained: a simplified description of the N-body motion of particles in the quasi-particle configuration; study of the dynamics of nuclear components which are not described by nucleons in their ground state. The following themes were presented: quasiparticles and the Green functions, relativistic aspects of the quasiparticle concept, the dimensions of nucleons in the nuclei and the EMC effect, quarks and gluons in the nuclei, the delta in the nuclei, the strangeness, quasiparticles far from the Fermi sea, diffusion of electrons, stellar evolution and nucleosynthesis [fr

  3. Dynamic polarisation of nuclei

    International Nuclear Information System (INIS)

    Borghini, M.; Abragam, A.

    1961-01-01

    In magnetic fields of about 13000 gauss, at a temperature of 1.5 deg. K, in samples of about 2 mm 3 , we have obtained by the 'solid effect' (application of a magnetic field at an appropriate frequency around 35000 MHz), nuclear polarizations /I of a few percent: 19 per cent for hydrogen nuclei in single crystals of La 2 Mg 3 (NO 3 ) 12 , 24H 2 O; 5 per cent for hydrogen nuclei in polystyrene; 6 per cent for fluorine nuclei in single crystals of LiF. (author) [fr

  4. Shell model calculations for exotic nuclei

    International Nuclear Information System (INIS)

    Brown, B.A.; Wildenthal, B.H.

    1991-01-01

    A review of the shell-model approach to understanding the properties of light exotic nuclei is given. Binding energies including p and p-sd model spaces and sd and sd-pf model spaces; cross-shell excitations around 32 Mg, including weak-coupling aspects and mechanisms for lowering the ntw excitations; beta decay properties of neutron-rich sd model, of p-sd and sd-pf model spaces, of proton-rich sd model space; coulomb break-up cross sections are discussed. (G.P.) 76 refs.; 12 figs

  5. Neutron halo in deformed nuclei

    International Nuclear Information System (INIS)

    Zhou Shangui; Meng Jie; Ring, P.; Zhao Enguang

    2010-01-01

    Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Contributions of the halo, deformation effects, and large spatial extensions of these systems are described in a fully self-consistent way by the DRHB equations in a spherical Woods-Saxon basis with the proper asymptotic behavior at a large distance from the nuclear center. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nucleus 44 Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the occurrence of this decoupling effects are discussed.

  6. The creation of new nuclei

    International Nuclear Information System (INIS)

    Armbruster, P.; Hessberger, F.P.

    1998-01-01

    In the last 60 years physicists have created 20 artificial elements beyond uranium. In 1934 Enrico Fermi predicted the creation of new elements by bombarding atoms with neutrons. This method led to the discovery of neptunium (Z=93), plutonium, americium, curium, berkelium, californium, einsteinium and fermium (Z=100). In fact the capture of a neutron is followed by a beta-decay which increases the atomic number (Z) by one unit. Beyond Z=100 beta-decay no more occurs so a new approach was necessary. Between the American Lawrence Berkeley Laboratory and the Russian Dubna Institute a fierce competition broke out to produce new elements by bombarding transuranium nuclei with light elements such as helium, carbon, nitrogen. This new method required heavy equipment: ion accelerator and detectors but led to the creation of all the elements from Z=101 to Z=106. A new idea was to provoke the fusion of heavy nuclei such as lead and bismuth with colliding argon, nickel or zinc ion beams. This method called 'cold fusion' opened the way to reach the nuclei beyond Z=107. In 1996 the element Z=112 was the last discovered. The next step could be the element Z=114 for which a particular stability is expected. (A.C.)

  7. Thermodynamical description of excited nuclei

    International Nuclear Information System (INIS)

    Bonche, P.

    1989-01-01

    In heavy ion collisions it has been possible to obtain composite systems at rather high excitation energies corresponding to temperatures of several MeV. The theoretical studies of these systems are based on concepts borrowed from thermodynamics or statistical physics, such as the temperature. In these lectures, we present the concepts of statistical physics which are involved in the physics of heavy ion as they are produced nowadays in the laboratory and also during the final stage of a supernova collapse. We do not attempt to describe the reaction mechanisms which yield such nuclear systems nor their decay by evaporation or fragmentation. We shall only study their static properties. The content of these lectures is organized in four main sections. The first one gives the basic features of statistical physics and thermodynamics necessary to understand quantum mechanics at finite temperature. In the second one, we present a study of the liquid-gas phase transition in nuclear physics. A phenomenological approach of the stability of hot nuclei follows. The microscopic point of view is proposed in the third part. Starting from the basic concepts derived in the first part, it provides a description of excited or hot nuclei which confirms the qualitative results of the second part. Furthermore it gives a full description of most properties of these nuclei as a function of temperature. Finally in the last part, a microscopic derivation of the equation of state of nuclear matter is proposed to study the collapse of a supernova core

  8. Proceedings of the specialists' meeting on 'nuclear spectroscopy and condensed matter physics using short-lived nuclei'

    International Nuclear Information System (INIS)

    Kobayashi, Yoshio; Shibata, Michihiro; Ohkubo, Yoshitaka

    2016-02-01

    The research reactor at Research Reactor Institute, Kyoto University is a very useful neutron generator, providing us neutron-rich unstable nuclei by bombarding nuclei with those neutrons. The produced unstable nuclei exhibit aspects distinct from those of stable ones. Nuclear structure studies on a variety of excited states reflecting dynamic nuclear properties are one of fascinating research subjects of physics. On the other hand, some radioactive nuclei can be used as useful probes for understanding interesting properties of condensed matters through studies of hyperfine interactions of static nuclear electromagnetic moments with extranuclear fields. Concerning these two research fields and related areas, the 2nd symposium under the title of 'Nuclear Spectroscopy and Condensed Matter Physics Using Short-lived Nuclei' was held at the Institute for two days on November 4 and 5 in 2015. We are pleased that many hot discussions were made. The talks were given on the followings: 1) Nuclear spectroscopic experiments, 2) TDPAC (time-differential perturbed angular correlation), 3) β-NMR (nuclear magnetic resonance), 4) Moessbauer spectroscopy, 5) muon, etc. This issue is the collection of 17 papers presented at the entitled meeting. The 6 of the presented papers are indexed individually. (J.P.N.)

  9. Quarks in nuclei

    International Nuclear Information System (INIS)

    Roberts, R.G.

    1984-11-01

    The paper concerns the behaviour of quarks in nuclei. Confinement size changes and dynamical rescaling; A dependence; low-x region; gluons and confinement size; and nucleons in a nucleus; are all discussed. (U.K.)

  10. The shape of nuclei

    International Nuclear Information System (INIS)

    Mackintosh, R.S.

    1977-01-01

    For the class of nuclei which are 'strongly deformed' it is possible to introduce the idea of an empirically measurable static nuclear shape. The limitations of this concept as applied to nuclei (fundamentally quantum-mechanical objects) are discussed. These are basically the limitations of the rotational model which must be introduced in order to define and measure nuclear shape. A unified discussion of the ways in which the shape has been parametrized is given with emphasis on the fact that different parametrizations correspond to different nuclear structures. Accounts of the various theoretical procedures for calculating nuclear shapes and of the interaction between nuclear shapes and nuclear spectroscopy are given. A coherent account of a large subset of nuclei (strongly deformed nuclei) can be given by means of a model in which the concept of nuclear shape plays a central role. (author)

  11. Structure of Warm Nuclei

    International Nuclear Information System (INIS)

    Aaberg, S.; Uhrenholt, H.

    2009-01-01

    We study the structure of nuclei in the energy region between the ground state and the neutron separation energy, here called warm nuclei. The onset of chaos in the nucleus as excitation energy is increased is briefly reviewed. Chaos implies fluctuations of energies and wave functions qualitatively the same for all chaotic nuclei. On the other hand, large structure effects are seen, e.g. in the level-density function at same excitation energies. A microscopic model for the level density is reviewed and we discuss effects on structure of the total level-density function, parity enhancement, and the spin distribution function. Comparisons to data are performed at the neutron separation energy for all observed nuclei, and structure of the level-density function for a few measured cases. The role of structure effects in the level-density function for fission dynamics is exemplified.

  12. Hot nuclei and fragmentation

    International Nuclear Information System (INIS)

    Guerreau, D.

    1993-01-01

    A review is made of the present status concerning the production of nuclei above 5 MeV temperature. Considerable progress has been made recently on the understanding of the formation and the fate of such hot nuclei. It appears that the nucleus seems more stable against temperature than predicted by static calculations. However, the occurrence of multifragment production at high excitation energies is now well established. The various experimental features of the fragmentation process are discussed. (author) 59 refs., 12 figs

  13. A new spin-oriented nuclei facility: POLAREX

    Directory of Open Access Journals (Sweden)

    Etilé A.

    2014-03-01

    Full Text Available Using the On-Line Nuclear Orientation method, POLAREX (POLARization of EXotic nuclei is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows to measure nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at Accélérateur Linéaire auprés du Tandem d’Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program.

  14. Training nuclei detection algorithms with simple annotations

    Directory of Open Access Journals (Sweden)

    Henning Kost

    2017-01-01

    Full Text Available Background: Generating good training datasets is essential for machine learning-based nuclei detection methods. However, creating exhaustive nuclei contour annotations, to derive optimal training data from, is often infeasible. Methods: We compared different approaches for training nuclei detection methods solely based on nucleus center markers. Such markers contain less accurate information, especially with regard to nuclear boundaries, but can be produced much easier and in greater quantities. The approaches use different automated sample extraction methods to derive image positions and class labels from nucleus center markers. In addition, the approaches use different automated sample selection methods to improve the detection quality of the classification algorithm and reduce the run time of the training process. We evaluated the approaches based on a previously published generic nuclei detection algorithm and a set of Ki-67-stained breast cancer images. Results: A Voronoi tessellation-based sample extraction method produced the best performing training sets. However, subsampling of the extracted training samples was crucial. Even simple class balancing improved the detection quality considerably. The incorporation of active learning led to a further increase in detection quality. Conclusions: With appropriate sample extraction and selection methods, nuclei detection algorithms trained on the basis of simple center marker annotations can produce comparable quality to algorithms trained on conventionally created training sets.

  15. Major new sources of biological ice nuclei

    Science.gov (United States)

    Moffett, B. F.; Hill, T.; Henderson-Begg, S. K.

    2009-12-01

    Almost all research on biological ice nucleation has focussed on a limited number of bacteria. Here we characterise several major new sources of biogenic ice nuclei. These include mosses, hornworts, liverworts and cyanobacteria. Ice nucleation in the eukaryotic bryophytes appears to be ubiquitous. The temperature at which these organisms nucleate is that at which the difference in vapour pressure over ice and water is at or close to its maximum. At these temperatures (-8 to -18 degrees C) ice will grow at the expense of supercooled water. These organisms are dependent for their water on occult precipitation - fog, dew and cloudwater which by its nature is not collected in conventional rain gauges. Therefore we suggest that these organism produce ice nuclei as a water harvesting mechanism. Since the same mechanism would also drive the Bergeron-Findeisen process, and as moss is known to become airborne, these nuclei may have a role in the initiation of precipitation. The properties of these ice nuclei are very different from the well characterised bacterial nuclei. We will also present DNA sequence data showing that, although related, the proteins responsible are only very distantly related to the classical bacterial ice nuclei.

  16. New isomeric states in 152,154,156Nd produced by spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Phan, X.H.; Theisen, C.; Belier, G.; Girod, M.; Meot, V.; Peru, S.; Astier, A.; Ducroux, L.; Meyer, M.; Redon, N.

    1998-01-01

    Isomeric states have been observed in fission-fragments produced by spontaneous fission of 252 Cf. These states are found in neutron rich nuclei of different structure and deformations. About 50 isomeric nuclei have been observed using coincidences between γ-rays identified in EUROGAM II and fission fragments detected in photovoltaic cells (SAPhIR). Lifetimes in the range from 20 ns to 2μs have been measured. Presented calculations based on HFB+D1S force on new measured isomeric states in the 152,154,156 Nd show evidence for K-isomers. (orig.)

  17. The future plan for the applications of RI produced in the proton-induced spallation-reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ikezoe, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    A plan of research facilities (transmutations of minor actinides and neutron scattering for material and life sciences) has been proposed in JAERI. This plan is based on a proton lineac with an energy of 1.5 GeV and a beam current of several mA. Among these facilities, we are planning to accelerate neutron-rich radioactive nuclei (RI) produced in the fission and spallation reactions of thorium or uranium bombarded by the intense high energy proton beams. The RI produced in an ion source are separated by a high resolution isotope separator and their charge states are changed to be negative to inject into the existing tandem-booster accelerator. Main purpose of this plan is to study the nuclear and chemical properties of neutron rich transactinium elements not yet synthesized and the nuclear structures of neutron rich nuclei far from the nuclear stability line. (author)

  18. Quest for superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Heenen, P.H. [Universite Libre de Bruxelles, Service de Physique Nucleaire Theorique (Belgium); Nazarewicz, W. [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics; Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej

    2002-02-01

    This article draws the long history of the discovery of new heavy nuclei since its beginning in 1940 when neptunium was found, and presents the current status of research in this field. The last 3 years have brought a number of experimental surprises which have truly rejuvenated the field. In January 1999, scientists from Dubna (Russia) reported the synthesis of 1 atom of element 114 ({sup 298}Uuq) in a hot fusion reaction between a {sup 48}Ca beam and a {sup 244}Pu target. This discovery was followed by 3 other reports from Dubna. First using the {sup 242}Pu({sup 48}Ca,3n) reaction, they produced {sup 287}Uuq. In 1999 the synthesis of another isotope of Z=114, the even-even {sup 288}Uuq was reported. The element Z=116 ({sup 292}Uuh) was discovered as a product of the {sup 248}Cm({sup 48}Ca,4n) reaction. The GSI (Germany) group found a new even isotope of the element 110: {sup 270}Uun and also {sup 272}Uuu (element 111) and {sup 277}Uub (element 112). 2 new isotopes of the element 107: {sup 266}Bh and {sup 267}Bh have been found at Berkeley (Usa). The synthesis of the new element Z=118 ({sup 293}Uuo) announced in 1999 by the Berkeley group was retracted 2 years later. The lifetimes reported for the elements {sup 284}Uub and {sup 280}Uun are by many orders of magnitude longer than those of the isotopes with Z{<=}112 previously discovered at GSI. (A.C.)

  19. Multifragmentation of hot nuclei

    International Nuclear Information System (INIS)

    Tamain, B.

    1990-10-01

    It is difficult to deposit a large amount (∼ 1 Gev) of excitation energy into a nucleus. And if one wants to deposit large excitation energy values, the best way consists of shooting a given target nucleus with several nucleons, which can be achieved by using intermediate energy (10-100 MeV/nucleon) heavy ions. Such very excited objects were named hot nuclei. The study of hot nuclei has been undertaken only for 7 years because intermediate energy heavy ion facilities were not available before. The game is then to determine the decay properties of such nuclei, their limits of existence. Their study is connected with general properties of nuclear matter: namely its equation of state. Of special interest, is the onset of a new decay mechanism: multifragmentation, which is the non-sequential disassembly of a hot nucleus into several light nuclei (often called intermediate-mass fragments or IMF) or particles. This paper, shows how this mechanism can reflect fundamental properties of nuclear matter, but also how its experimental signature is difficult to establish. Multifragmentation has also been studied by using very energetic projectiles (protons and heavy ions) in the relativistic or ultra-relativistic region. The multifragmentation question of hot nuclei is far from being solved. One knows that IMF production increases when the excitation energy brought into a system is strongly increased, but very little is known about the mechanisms involved and a clear onset for multifragmentation is not established

  20. Relativistic exotic nuclei as projectile beams. New perspectives of studies on the properties of nuclei

    International Nuclear Information System (INIS)

    Geissel, H.

    1997-03-01

    Examinations of the production cross-sections and the kinematics permitted refinement of model concepts of the peripheral reactions in exotic nuclei at energies from 100 to 1000 A MeV. Due to the strong selectivity and resolution achieved it was possible to discover a large number of novel isotopes at the fragment separator FRS, despite the relatively low projectile beam intensities of the SIS. The two twice magic nuclei found, Ni 78 and Sn 100, are particularly interesting, as they could not be measured so far with other experimental systems. Fission of relativistic uranium ions proved to be a particularly successful process yielding many medium-heavy, neutron-rich nuclei. Insight into the structure of light neutron halos could be improved. The superlarge spatial dimensions of the nuclear halos is discussed. (orig./CB) [de

  1. The disulfide-rich Metridia luciferase refolded from E. coli inclusion bodies reveals the properties of a native folded enzyme produced in insect cells.

    Science.gov (United States)

    Markova, Svetlana V; Larionova, Marina D; Gorbunova, Darya A; Vysotski, Eugene S

    2017-10-01

    The bioluminescence of a marine copepod Metridia longa is determined by a small secreted coelenterazine-dependent luciferase that uses coelenterazine as a substrate of enzymatic reaction to generate light (λ max =480nm). To date, four different isoforms of the luciferase differing in size, sequences, and properties have been cloned by functional screening. All of them contain ten conserved Cys residues that suggests up to five SS intramolecular bonds per luciferase molecule. Whereas the use of copepod luciferases as bioluminescent reporters in biomedical research in vivo is growing from year to year, their application for in vitro assays is still limited by the difficulty in obtaining significant amounts of luciferase. The most cost-effective host for producing recombinant proteins is Escherichia coli. However, prokaryotic and eukaryotic cells maintain the reductive environment in cytoplasm that hinders the disulfide bond formation and consequently the proper folding of luciferase. Here we report the expression of the MLuc7 isoform of M. longa luciferase in E. coli cells and the efficient procedure for refolding from inclusion bodies yielding a high-active monomeric protein. Furthermore, in a set of identical experiments we demonstrate that bioluminescent and structural features of MLuc7 produced in bacterial cells are identical to those of MLuc7 isoform produced from culture medium of insect cells. Although the yield of high-purity protein is only 6mg/L, the application of E. coli cells to produce the luciferase is simpler and more cost-effective than the use of insect cells. We expect that the suggested technology of Metridia luciferase production allows obtaining of sufficient amounts of protein both for the development of novel in vitro analytical assays with the use of MLuc7 as a label and for structural studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Electron-microscope study of cloud and fog nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ogiwara, S; Okita, T

    1952-01-01

    Droplets of clouds on a mountain and of fog in an urban area were captured and the form, nature and size of their nuclei were studied by means of an electron-microscope and by a chamber of constant humidity. These nuclei have similar form and nature to the hygroscopic particles in haze and to the artificially produced combustion particles. No sea-salt nuclei were found in our observations, therefore, sea-spray appears to be an insignificant source of condensation nuclei. It was found that both the cloud and the fog nuclei originated in combustion products which were the mixture of hygroscopic and non-hygroscopic substances, and that the greater part of the nuclei did not contain pure sulfuric acid.

  3. Critical-point nuclei

    International Nuclear Information System (INIS)

    Clark, R.M.

    2004-01-01

    It has been suggested that a change of nuclear shape may be described in terms of a phase transition and that specific nuclei may lie close to the critical point of the transition. Analytical descriptions of such critical-point nuclei have been introduced recently and they are described briefly. The results of extensive searches for possible examples of critical-point behavior are presented. Alternative pictures, such as describing bands in the candidate nuclei using simple ΔK = 0 and ΔK = 2 rotational-coupling models, are discussed, and the limitations of the different approaches highlighted. A possible critical-point description of the transition from a vibrational to rotational pairing phase is suggested

  4. Use of by-products rich in carbon and nitrogen as a nutrient source to produce Bacillus thuringiensis (Berliner)-based bio pesticide

    International Nuclear Information System (INIS)

    Valicente, Fernando H.; Mourao, Andre H.C.

    2008-01-01

    The amount and sources of carbon and nitrogen used to produce Bacillus thuringiensis (Berliner)-based biopesticide may influence the quality of the fi nal product. The objective of this research was to test different levels of carbon and nitrogen: medium 1 - 1.5% maize glucose + 0.5% soy fl our, medium 2 - 3.0% maize glucose + 1.0% soy flour, medium 3 - 1.0% maize glucose + 3.0% soy fl our and medium 4 - Luria Bertani (LB) + salts (FeSO 4 , ZnSO 4 , MnSO 4 , MgSO 4 ). The seed culture was produced in LB medium plus salt, under agitation (200 rpm) for 18h at 30 deg C. The strain 344 of Bt was used (B. thuringiensis var tolworthi - belonging to the EMBRAPA's Bt Bank). The pH was measured at regular intervals, and After culturing for 96h, the pH of the four tested media was basified (6.91 and 8.15), the number of spores yielded 4.39 x 10 9 spores/ml in medium 3, where the amount of protein is high. The dry biomass weight accumulated in media 3 was 39.3 g/l. Mortality of 2-day-old larvae Spodoptera frugiperda (J.E. Smith) was 100% when using Bt produced in media 3 and 4. CL 50 for medium 3 was 8.4 x 10 6 spores/ml. All tested media were satisfactory to Bt growth, and medium 3 was the most promising to be used on a large scale Bt-based biopesticide production. (author)

  5. Use of by-products rich in carbon and nitrogen as a nutrient source to produce Bacillus thuringiensis (Berliner)-based bio pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Valicente, Fernando H. [EMBRAPA Milho e Sorgo, Sete Lagoas, MG (Brazil)]. E-mail: valicent@cnpms.embrapa.br; Mourao, Andre H.C. [Curso de Meio Ambiente, Sete Lagoas, MG (Brazil)

    2008-11-15

    The amount and sources of carbon and nitrogen used to produce Bacillus thuringiensis (Berliner)-based biopesticide may influence the quality of the fi nal product. The objective of this research was to test different levels of carbon and nitrogen: medium 1 - 1.5% maize glucose + 0.5% soy fl our, medium 2 - 3.0% maize glucose + 1.0% soy flour, medium 3 - 1.0% maize glucose + 3.0% soy fl our and medium 4 - Luria Bertani (LB) + salts (FeSO{sub 4}, ZnSO{sub 4}, MnSO{sub 4}, MgSO{sub 4}). The seed culture was produced in LB medium plus salt, under agitation (200 rpm) for 18h at 30 deg C. The strain 344 of Bt was used (B. thuringiensis var tolworthi - belonging to the EMBRAPA's Bt Bank). The pH was measured at regular intervals, and After culturing for 96h, the pH of the four tested media was basified (6.91 and 8.15), the number of spores yielded 4.39 x 10{sup 9} spores/ml in medium 3, where the amount of protein is high. The dry biomass weight accumulated in media 3 was 39.3 g/l. Mortality of 2-day-old larvae Spodoptera frugiperda (J.E. Smith) was 100% when using Bt produced in media 3 and 4. CL{sub 50} for medium 3 was 8.4 x 10{sup 6} spores/ml. All tested media were satisfactory to Bt growth, and medium 3 was the most promising to be used on a large scale Bt-based biopesticide production. (author)

  6. Interactions of 10.6 GeV/n gold nuclei with light and heavy target nuclei in nuclear emulsion

    International Nuclear Information System (INIS)

    Cherry, M.L.; Denes-Jones, P.

    1994-03-01

    We have investigated the particle production and fragmentation of nuclei participating in the interactions of 10.6 GeV/n gold nuclei in nuclear emulsions. A new criteria has been developed to distinguish between the interactions of these gold nuclei with the light (H, C, N, O) and heavy (Ag, Br) target nuclei in the emulsion. This has allowed separate analyzes of the multiplicity and pseudo-rapidity distributions of the singly charged particles emitted in Au-(H, C, N, O) and Au-(Ag, Br) interactions, as well as of the models of breakup of the projectile and target nuclei. The pseudo-rapidity distributions show strong forward asymmetries, particularly for the interactions with the light nuclei. Heavy target nuclei produce a more severe breakup of the projectile gold nucleus than do the lighter targets. A negative correlation between the number of fragments emitted from the target nuclei and the degree of centrality of the collisions has been observed, which can be attributed to the total destruction of the relatively light target nuclei by these very heavy projectile nuclei. (author). 14 refs, 11 figs, 1 tab

  7. Weak interactions with nuclei

    International Nuclear Information System (INIS)

    Walecka, J.D.

    1983-01-01

    Nuclei provide systems where the strong, electomagnetic, and weak interactions are all present. The current picture of the strong interactions is based on quarks and quantum chromodynamics (QCD). The symmetry structure of this theory is SU(3)/sub C/ x SU(2)/sub W/ x U(1)/sub W/. The electroweak interactions in nuclei can be used to probe this structure. Semileptonic weak interactions are considered. The processes under consideration include beta decay, neutrino scattering and weak neutral-current interactions. The starting point in the analysis is the effective Lagrangian of the Standard Model

  8. Quarks in nuclei

    International Nuclear Information System (INIS)

    Rho, M.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

    1983-01-01

    Some features of quark degrees of freedom in nuclei are discussed in the light of recent developments in QCD. The principal aim of this talk is to propose, and give a tentative support to, the motion that one can study through nuclear matter different facets of the vacuum structure implied by quantum chromodynamics (QCD). This will be done using the recent (exciting) results obtained in particle physics, in particular lattice gauge calculations. Relevance of this aspect of problem to quark degrees of freedom as well as meson degrees of freedom in nuclei will be discussed. (orig.)

  9. Disintegration of comet nuclei

    Science.gov (United States)

    Ksanfomality, Leonid V.

    2012-02-01

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies.

  10. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2002-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on kinematic separation and mass analysis of heavy recoiling nuclei, dynamical effects prior to heavy ion fusion, VACTIV-DELPHI graphical dialog based program for the analysis of gamma-ray spectra, irradiation of nuclear emulsions in relativistic beams of 6 He and 3 H nuclei, optical and structural investigations of PLZT x/65/35 (x = 4, 8 %) ferroelectric ceramics irradiated by a high-current pulsed electron beam, the oscillating charge and first evidence for neutrinoless double beta decay

  11. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2001-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on physics from extra dimensions, new physics in the new millennium with GENIUS: double beta decay, dark matter, solar neutrinos, the (μ - , e + ) conversion in nuclei mediated by light Majorana neutrinos, exotic muon-to-positron conversion in nuclei: partial transition sum evaluation by using shell model, solar neutrino problem accounting for self consistent magnetohydrodynamics solution for solar magnetic fields, first neutrino observations from the Sudbury neutrino observatory and status report on BOREXINO and results of the muon-background measurements at CERN

  12. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1976-01-01

    Nuclear structure theories are reviewed concerned with nuclei rotational motion. The development of the deformed nucleus model facilitated a discovery of rotational spectra of nuclei. Comprehensive verification of the rotational scheme and a successful classification of corresponding spectra stimulated investigations of the rotational movement dynamics. Values of nuclear moments of inertia proved to fall between two marginal values corresponding to rotation of a solid and hydrodynamic pattern of an unrotating flow, respectively. The discovery of governing role of the deformation and a degree of a symmetry violence for determining rotational degrees of freedon is pointed out to pave the way for generalization of the rotational spectra

  13. Direct mass measurements in the light neutron-rich region using a combined energy and time-of-flight technique

    International Nuclear Information System (INIS)

    Pillai, C.; Swenson, L.W.; Vieira, D.J.; Butler, G.W.; Wouters, J.M.; Rokni, S.H.; Vaziri, K.; Remsberg, L.P.

    1985-01-01

    This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET 2 method. This technique has the advantage that many particle-bound nuclei, produced in fragmentation reactions can be measured simultaneously, independent of their N or Z. The main disadvantage of this approach is that both energy and time-of-flight must be measured precisely on an absolute scale. Although some mass walk with N and Z was observed in this experiment, these uncertainties were largely removed by extrapolating the smooth dependence observed for known nuclei which lie closer to the valley of β-stability. Mass measurements for several neutron-rich light nuclei ranging from 17 C to 26 Ne have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of 20 N and 24 F have been determined for the first time

  14. Medium energy hadron scattering from nuclei

    International Nuclear Information System (INIS)

    Ginocchio, J.N.; Wenes, G.

    1986-01-01

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a γ unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from 154 Sm and 154 Gd. 27 refs., 5 figs., 1 tab

  15. Static and dynamic deformations of actinide nuclei

    International Nuclear Information System (INIS)

    Rozmej, P.

    1985-09-01

    The zero-point quadrupole-hexadecapole vibrations have been taken into account to calculate dynamical deformations for even-even actinide nuclei. The collective and intrinsic motions are separated according to the Born-Oppenheimer approximation. The collective Hamiltonian is constructed using the macroscopic-microscopic method in the potential energy part and the cranking model in the kinetic energy part. The BCS theory with a modified oscillator potential is applied to describe the intrinsic motion of nucleons. A new set of Nilsson potential parameters, which produces a much better description of the properties of light actinide nuclei, has also been found. (orig.)

  16. Symmetries and nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Nuclei are very useful for testing symmetries, and for studies of symmetry breaking. This thesis is illustrated for two improper space-time transformations, parity and time-reversal and for one internal symmetry: charge symmetry and independence. Recent progress and present interest is reviewed. 23 refs., 8 figs., 2 tabs

  17. Electroweak interactions in nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1984-06-01

    Topics include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms. 52 references

  18. Transfer involving deformed nuclei

    International Nuclear Information System (INIS)

    Rasmussen, J.O.; Guidry, M.W.; Canto, L.F.

    1985-03-01

    Results are reviewed of 1- and 2-neutron transfer reactions at near-barrier energies for deformed nuclei. Rotational angular momentum and excitation patterns are examined. A strong tendency to populating high spin states within a few MeV of the yrast line is noted, and it is interpreted as preferential transfer to rotation-aligned states. 16 refs., 12 figs

  19. Nucleons in nuclei (II)

    International Nuclear Information System (INIS)

    Laget, J.M.

    1988-01-01

    This summary is a review of our understanding of nuclei in terms of hadrons exchanging mesons. The open problems are: the determination of the high momentum components of nuclear systems, the role of the three-body forces and the nature of the short range correlations. The ways of studying these problems are discussed

  20. Electromagnetic structure of nuclei

    International Nuclear Information System (INIS)

    Arnold, R.G.

    1986-07-01

    A brief review is given of selected topics in the electromagnetic structure of nucleons and nuclei, including nucleon form factors from both quantum chromodynamics and electron scattering data, measurements of the deuteron and triton form factors, quasi-elastic scattering, and the EMC effect. 47 refs., 13 figs

  1. Rotational motion in nuclei

    International Nuclear Information System (INIS)

    Bohr, A.

    1977-01-01

    History is surveyed of the development of the theory of rotational states in nuclei. The situation in the 40's when ideas formed of the collective states of a nucleus is evoked. The general rotation theory and the relation between the single-particle and rotational motion are briefly discussed. Future prospects of the rotation theory development are indicated. (I.W.)

  2. Mesons and light nuclei

    International Nuclear Information System (INIS)

    Truhlik, E.; Mach, R.

    1992-01-01

    62 papers and one summary talk were presented at the conference, on subject matters in between nuclear physics (mainly light nuclei) and elementary particle physics, as indicated by the session headings (1) Electroweak nuclear interaction (2) Nuclear physics with pions and antiprotons (3) Nuclear physics with strange particles (4) Relativistic nuclear physics (5) Quark degrees of freedom. (Quittner)

  3. Radii of radioactive nuclei

    International Nuclear Information System (INIS)

    Mittig, W.; Plagnol, E.; Schutz, Y.

    1989-11-01

    A new simple direct method for the measurement of the total reaction cross section (σ R ) for several light radioactive nuclei (A≤40) is developed. From that, the reduced strong absorption radii (r o 2 ) are obtained. A comparison is made with data obtained by other techniques. A strong isospin dependence of the nuclear radii is observed. (L.C.) [pt

  4. Alpha clustering in nuclei

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1990-01-01

    The effects of nucleon clustering in nuclei are described, with reference to both nuclear structure and nuclear reactions, and the advantages of using the cluster formalism to describe a range of phenomena are discussed. It is shown that bound and scattering alpha-particle states can be described in a unified way using an energy-dependent alpha-nucleus potential. (author)

  5. Particles, imaging and nuclei

    International Nuclear Information System (INIS)

    Harris, J.

    1986-01-01

    The book on particles, imaging and nuclei is one of the Background Readers for the Revised Nuffield Advanced Physics course. The contents contain five educational articles, which extend concepts covered in the course and examine recent developments in physics. Four of the articles on:- particles and the forces of nature, radioisotopes, lasers probe the atomic nucleus, and nuclear history, are indexed separately. (UK)

  6. 3rd International conference on nuclei far from stability, Cargese, Corsica, 19-26 May 1976

    International Nuclear Information System (INIS)

    1976-01-01

    These conference proceedings contain 103 contributions which are grouped under the following headings: Experimental methods and techniques; Perspectives in research on exotic nuclei; Nuclear masses - experiment and theory; Nuclear spins, moments, and radii; Light nuclei; Delayed particle emission and statistical aspects; Excited states of neutron-deficient nuclei; Excited states of fission products and other neutron-rich isotopes; Heavy elements and astrophysical aspects. Also included are the Scientific programme and a List of participants. (AJ)

  7. Accretion disks in active galactic nuclei

    International Nuclear Information System (INIS)

    Shields, G.A.

    1989-01-01

    Active galactic nuclei (AGN) have taunted astrophysicists for a quarter century. How do these objects produce huge luminosities---in some cases, far outshining our galaxy---from a region perhaps no larger than the solar system? Accretion onto supermassive black holes has been widely considered the best buy in theories of AGN. Much work has gone into accretion disk theory, searches for black holes in galactic nuclei, and observational tests. These efforts have not proved the disk model, but there is progress. Evidence for black holes in the nuclei of nearby galaxies is provided by observations of stellar velocities, and radiation from the disk's hot surface may be observed in the ultraviolet (UV) and neighboring spectral bands. In the review, the author describe some of the recent work on accretion disks in AGN, with an emphasis on points of contact between theory and observation

  8. Electron scattering and reactions from exotic nuclei

    International Nuclear Information System (INIS)

    Karataglidis, S.

    2017-01-01

    The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)

  9. Electron scattering and reactions from exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)

    2017-04-15

    The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)

  10. Fundamental Physics with Electroweak Probes of Nuclei

    Science.gov (United States)

    Pastore, Saori

    2018-02-01

    The past decade has witnessed tremendous progress in the theoretical and computational tools that produce our understanding of nuclei. A number of microscopic calculations of nuclear electroweak structure and reactions have successfully explained the available experimental data, yielding a complex picture of the way nuclei interact with electroweak probes. This achievement is of great interest from the pure nuclear-physics point of view. But it is of much broader interest too, because the level of accuracy and confidence reached by these calculations opens up the concrete possibility of using nuclei to address open questions in other sub-fields of physics, such as, understanding the fundamental properties of neutrinos, or the particle nature of dark matter. In this talk, I will review recent progress in microscopic calculations of electroweak properties of light nuclei, including electromagnetic moments, form factors and transitions in between lowlying nuclear states along with preliminary studies for single- and double-beta decay rates. I will illustrate the key dynamical features required to explain the available experimental data, and, if time permits, present a novel framework to calculate neutrino-nucleus cross sections for A > 12 nuclei.

  11. The decay of hot nuclei

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-11-01

    The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs

  12. Isotope shifts in unstable nuclei

    International Nuclear Information System (INIS)

    Rebel, H.

    1980-05-01

    Current experimental investigations of isotope shifts in atomic spectra of unstable nuclei and the resulting information about size and shape of nuclei far off stability are discussed with reference to some representative examples. (orig.)

  13. The cysteine rich necrotrophic effector SnTox1 produced by Stagonospora nodorum triggers susceptibility of wheat lines harboring Snn1.

    Directory of Open Access Journals (Sweden)

    Zhaohui Liu

    2012-01-01

    Full Text Available The wheat pathogen Stagonospora nodorum produces multiple necrotrophic effectors (also called host-selective toxins that promote disease by interacting with corresponding host sensitivity gene products. SnTox1 was the first necrotrophic effector identified in S. nodorum, and was shown to induce necrosis on wheat lines carrying Snn1. Here, we report the molecular cloning and validation of SnTox1 as well as the preliminary characterization of the mechanism underlying the SnTox1-Snn1 interaction which leads to susceptibility. SnTox1 was identified using bioinformatics tools and verified by heterologous expression in Pichia pastoris. SnTox1 encodes a 117 amino acid protein with the first 17 amino acids predicted as a signal peptide, and strikingly, the mature protein contains 16 cysteine residues, a common feature for some avirulence effectors. The transformation of SnTox1 into an avirulent S. nodorum isolate was sufficient to make the strain pathogenic. Additionally, the deletion of SnTox1 in virulent isolates rendered the SnTox1 mutated strains avirulent on the Snn1 differential wheat line. SnTox1 was present in 85% of a global collection of S. nodorum isolates. We identified a total of 11 protein isoforms and found evidence for strong diversifying selection operating on SnTox1. The SnTox1-Snn1 interaction results in an oxidative burst, DNA laddering, and pathogenesis related (PR gene expression, all hallmarks of a defense response. In the absence of light, the development of SnTox1-induced necrosis and disease symptoms were completely blocked. By comparing the infection processes of a GFP-tagged avirulent isolate and the same isolate transformed with SnTox1, we conclude that SnTox1 may play a critical role during fungal penetration. This research further demonstrates that necrotrophic fungal pathogens utilize small effector proteins to exploit plant resistance pathways for their colonization, which provides important insights into the molecular

  14. [The distribution of NADPH-diaphorase and neuronal no synthase in rat medulla oblongata nuclei].

    Science.gov (United States)

    Chertok, V M; Kotsuba, A E

    2013-01-01

    The distribution of nitroxide ergic neurons in the medulla oblongata nuclei in Wistar rats (n = 8) was studied histochemically (NADPH-diaphorase) and using immunohistochemistry with an antiserum against neuronal form of nitric oxide synthase (nNOS). NADPH-diaphorase activity was found in large and small neurons of the sensory, autonomic and motor nuclei. The latter were especially rich in the cells demonstrating the activity of the enzyme. Unlike NADPH-diaphorase, nNOS in the corresponding nuclei was always detected in the fewer number of neurons, predominantly of small sizes. The sensory nuclei (nucleus of solitary tract, reticular parvocellular and lateral nuclei, spinal nucleus of the trigeminal nerve) contained 1.5-3 times more nNOS neurons than in motor nuclei. In some nuclei (nucleus ambiguus, hypoglossal nerve nucleus), containing numerous NADPH-diaphorase-positive neurons, immunoreactive cells were particularly rare.

  15. Energetic Nuclei, Superdensity and Biomedicine

    Science.gov (United States)

    Baldin, A. M.

    1977-01-01

    High-energy, relativistic nuclei were first observed in cosmic rays. Studing these nuclei has provided an opportunity for analyzing the composition of cosmic rays and for experimentally verifying principles governing the behavior of nuclear matter at high and super-high temperatures. Medical research using accelerated nuclei is suggested.…

  16. Population of Nuclei Via 7Li-Induced Binary Reactions

    International Nuclear Information System (INIS)

    Clark, Rodney M.; Phair, Larry W.; Descovich, M.; Cromaz, Mario; Deleplanque, M.A.; Fall on, Paul; Lee, I-Yang; Macchiavelli, A.O.; McMahan, Margaret A.; Moretto, Luciano G.; Rodriguez-Vieitez, E.; Sinha, Shrabani; Stephens, Frank S.; Ward, David; Wiedeking, Mathis

    2005-01-01

    The authors have investigated the population of nuclei formed in binary reactions involving 7 Li beams on targets of 160 Gd and 184 W. The 7 Li + 184 W data were taken in the first experiment using the LIBERACE Ge-array in combination with the STARS Si ΔE-E telescope system at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory. By using the Wilczynski binary transfer model, in combination with a standard evaporation model, they are able to reproduce the experimental results. This is a useful method for predicting the population of neutron-rich heavy nuclei formed in binary reactions involving beams of weakly bound nuclei formed in binary reactions involving beams of weakly bound nuclei and will be of use in future spectroscopic studies

  17. Investigation of exotic modes of spinning nuclei near Zr

    Indian Academy of Sciences (India)

    2014-04-01

    Apr 1, 2014 ... c Indian Academy of Sciences. Vol. ... transition as the high-j orbitals are occupied. ... to show Jacobi shape transition based on the model calculations [7]. ... vibration with other modes, high spin states of neutron-rich nuclei in ...

  18. Structure of the drip line nuclei probed by separation energies

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Zdeněk

    2006-01-01

    Roč. 15, č. 7 (2006), s. 1471-1475 ISSN 0218-3013 Institutional research plan: CEZ:AV0Z10480505 Keywords : Neutron-rich nuclei * Shell- modell * Magic-number Subject RIV: BE - Theoretical Physics Impact factor: 0.810, year: 2006

  19. New isomeric states in {sup 152,154,156}Nd produced by spontaneous fission of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Phan, X.H.; Theisen, C. [Commissariat l`Energie Atomique de Saclay, Gif sur Yvette (France). DSM/DAPINA/SPhN; Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires de Bordeaux-Gradignan, Domaine du Haut Vigneau, F-33175 Gradignan (France); Belier, G.; Girod, M.; Meot, V.; Peru, S. [Commissariat a l`Energie Atomique de Bruyeres-le-Chatel, DAM/SPN, BP12, F-91680 Bruyeres-le-Chatel (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Institut de Physique Nucleaire de Lyon, F-69622 Villeurbanne Cedex (France)

    1998-04-01

    Isomeric states have been observed in fission-fragments produced by spontaneous fission of {sup 252}Cf. These states are found in neutron rich nuclei of different structure and deformations. About 50 isomeric nuclei have been observed using coincidences between {gamma}-rays identified in EUROGAM II and fission fragments detected in photovoltaic cells (SAPhIR). Lifetimes in the range from 20 ns to 2{mu}s have been measured. Presented calculations based on HFB+D1S force on new measured isomeric states in the {sup 152,154,156}Nd show evidence for K-isomers. (orig.) With 8 figs., 27 refs.

  20. Neutron-rich isotopes of the lightest elements

    International Nuclear Information System (INIS)

    Oganesyan, Yu.Ts.; Penionzhkevich, Yu.Eh.; Kalpakchieva, R.

    1989-01-01

    A review is presented of the experimental investigations on the stability of very neutron-rich light nuclei carried out at the JINR Laboratory of Nuclear Reactions. Results on mass excess measurements are reported for 4 H, 5 H, 6 H, 7 H and for the superheavy helium isotope 9 He. Some results from the joint JINR-Ganil experiment on the search for and study of new neutron-rich light nuclei are also given. Analyzed are new possibilities for the investigation of multineutron decay of light nuclei. 14 refs.; 10 figs

  1. Decay Studies of Very Neutron Rich Nuclei near 78Ni

    International Nuclear Information System (INIS)

    Winger, J. A.; Ilyushkin, S.; Korgul, A.; Gross, Carl J; Rykaczewski, Krzysztof Piotr; Batchelder, J. C.; Goodin, C.; Grzywacz, R.; Hamilton, J. H.; Krolas, W.; Liddick, Sean; Mazzocchi, C.; Nelson, C.; Padgett, Stephen; Piechaczek, A.; Rajabali, M. M.; Shapira, Dan; Zganjar, E. F.

    2008-01-01

    The properties of beta-gamma and beta-delayed neutron emission from 76-79 Cu and 83-85 Ga were measured at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. Selected results on the decay properties of copper isotopes are briefly presented and discussed

  2. Single-Particle Structure of Neutron-Rich Nuclei

    International Nuclear Information System (INIS)

    Cizewski, Jolie; Jones, K.L.; Thomas, J.S.; Bardayan, Daniel W.; Blackmon, Jeff C.; Gross, Carl J.; Liang, J. Felix; Shapira, Dan; Smith, Michael Scott; Stracener, Daniel W.; Kozub, R.L.; Nesaraja, Caroline D.; Greife, U.; Livesay, Jake; Ma, Zhanwen

    2004-01-01

    Neutron transfer (d,p) reactions have been measured with rare isotope beams of 132Sn, 130Sn and 134Te accelerated to ∼4.5 MeV/u interacting with CD2 targets. Reaction protons were detected in an early implementation of the ORRUBA array of position-sensitive silicon strip detectors. Neutron excitations in the 2f7/2, 3p3/2, 3p1/2 and 2f5/2 orbitals were populated.

  3. New type of asymmetric fission in proton-rich nuclei

    CERN Document Server

    Andreyev, A N; Huyse, M; Van Duppen, P; Antalic, S; Barzakh, A; Bree, N; Cocolios, T E; Comas, V F; Diriken, J; Fedorov, D; Fedosseev, V; Franchoo, S; Heredia, J A; Ivanov, O; Koster, U; Marsh, B A; Nishio, K; Page, R D; Patronis, N; Seliverstov, M; Tsekhanovich, I; Van den Bergh, P; Van De Walle, J; Venhart, M; Vermote, S; Veselsky, M; Wagemans, C; Ichikawa, T; Iwamoto, A; Moller, P; Sierk, A J

    2010-01-01

    A very exotic process of ${\\beta}$-delayed fission of $^{180}$Tl is studied in detail by using resonant laser ionization with subsequent mass separation at ISOLDE (CERN). In contrast to common expectations, the fission-fragment mass distribution of the post-${\\beta}$-decay daughter nucleus $^{180}$Hg (N/Z=1.25) is asymmetric. This asymmetry is more surprising since a mass-symmetric split of this extremely neutron-deficient nucleus would lead to two $^{90}$Zr fragments, with magic N=50 and semimagic Z=40. This is a new type of asymmetric fission, not caused by large shell effects related to fragment magic proton and neutron numbers, as observed in the actinide region. The newly measured branching ratio for $\\beta$-delayed fission of $^{180}$Tl is 3.6(7)×10$^{-3}$%, approximately 2 orders of magnitude larger than in an earlier study.

  4. Structure of light neutron-rich nuclei through Coulomb dissociation

    Indian Academy of Sciences (India)

    The data analysis for Coulomb breakup of. ½ .... C (605 MeV/u) breaking up into a neutron and a .... direct break up model delivers a cross section of 107 mb for a ... separation energy for the last neutron in the even isotopes = 20 to 24 is 7 to 8 ...

  5. Beta decay of neutron-rich transuranic nuclei

    International Nuclear Information System (INIS)

    Hoff, R.W.

    1986-01-01

    Allowance is made for beta-delayed fission in the calculation of the mass yield of underground thermonuclear explosions. This allowance is made by calculating a correction factor by four different methods. These correction factors are applied to a simple model of product yield and the accuracy and potential usefulness of the results are discussed. 19 refs., 3 figs., 1 tab

  6. New excitation modes in halo nuclei

    International Nuclear Information System (INIS)

    Sagawa, H.

    1992-01-01

    Multipole resonances in exotic neutron-rich nuclei are addressed on the basis of microscopic calculations, i.e., in the framework of the self-consistent H-F + RPA theory. A bunch of resonances with multipoles J π = 0 + , 1 - and 2 + is found near the particle threshold E x ∼ 1 MeV in 10 He having significant portions of the sum rule values and narrow widths. The long tail of the loosely-bound neutrons is the cause of the threshold anomaly of these resonances

  7. Disintegration of comet nuclei

    International Nuclear Information System (INIS)

    Ksanfomality, Leonid V

    2012-01-01

    The breaking up of comets into separate pieces, each with its own tail, was seen many times by astronomers of the past. The phenomenon was in sharp contrast to the idea of the eternal and unchangeable celestial firmament and was commonly believed to be an omen of impending disaster, especially for comets with tails stretching across half the sky. It is only now that we have efficient enough space exploration tools to see comet nuclei and even - in the particular case of small comet Hartley-2 in 2010 - to watch their disintegration stage. There are also other suspected candidates for disintegration in the vast family of comet nuclei and other Solar System bodies. (physics of our days)

  8. Pions scatter by nuclei

    International Nuclear Information System (INIS)

    Huefner, J.

    1975-01-01

    Are pions a good tool to study nuclei. If the emphasis of this question rests on ''tool'', the answer must be ''not yet.'' The reason: one does not even understand how a pion interacts with a nucleus. This is part of the many-body problem for strongly interacting particles and its study is a basic problem in physics. One must investigate questions like: Can one understand pion-nucleus interactions from pion-nucleon physics. How does a Δ-resonance look in nuclei. Once one has solved those basic problems, there will be spinoffs in medical, technical and nuclear areas. Then pions can be used as a tool to study nuclear properties

  9. Chaos in collective nuclei

    International Nuclear Information System (INIS)

    Whelan, N.D.

    1993-01-01

    Random Matrix Theory successfully describes the statistics of the low-lying spectra of some nuclei but not of others. It is currently believed that this theory applies to systems in which the corresponding classical motion is chaotic. This conjecture is tested for collective nuclei by studying the Interacting Boson Model. Quantum and classical measures of chaos are proposed and found to be in agreement throughout the parameter space of the model. For some parameter values the measures indicate the presence of a previously unknown approximate symmetry. A phenomenon called partial dynamical symmetry is explored and shown to lead to a suppression of chaos. A time dependent function calculated from the quantum spectrum is discussed. This function is sensitive to the extent of chaos and provides a robust method of analyzing experimental spectra

  10. Contact nuclei formation in aqueous dextrose solutions

    Science.gov (United States)

    Cerreta, Michael K.; Berglund, Kris A.

    1990-06-01

    A laser Raman microprobe was used in situ to observe the growth of alpha dextrose monohydrate on alpha anhydrous dextrose crystals. The Raman spectra indicate growth of the monohydrate below 28.1°C, but the presence of only the anhydrous form above 40.5°C. Contact nucleation experiments with parent anhydrous crystals yielded only monohydrate nuclei below 28.1°C, while contacts in solutions between 34.5 and 41.0°C produced both crystalline forms, and contacts in solutions above 43.5°C produced only anhydrous nuclei. The inability of the monohydrate to grow on anhydrous crystals in the same solution that forms the two crystalline phases with a single contact precludes a simple attrition mechanism of nuclei formation. For the same reason, the hypothetical mechanism involving parent crystal stabilization of pre-crystalline clusters, allowing the clusters to grow into nuclei, is also contradicted. A third, mechanism, which may be a combination of the two, is believed to apply.

  11. Chaotic behavior in nuclei

    International Nuclear Information System (INIS)

    Mitchel, G.; Shriner, J.

    2005-01-01

    Although the predictions of Random Matrix Theory (RMT) were available by the early 1960s, data of sufficiently high quality to adequately test the theory were only obtained a decade later by Rainwater. It was another decade later that Bohigas, Haq and Pandey combined the best available nuclear resonance data - the Columbia neutron resonances in heavy nuclei and the TUNL proton resonances in lighter nuclei - to form the Nuclear Data Ensemble. They obtained excellent agreement for the level statistics with the RMT predictions. The expected Porter-Thomas (PT) distribution was considered very early. However, since the widths (amplitudes squared) are measured, the predicted Gaussian distribution for the amplitudes was only qualitatively confirmed. A much more sensitive test was performed by measuring two widths and the relative phase between the two amplitudes. By comparison of the width and amplitude correlations, the Gaussian distribution was confirmed at the 1% level. Following the Bohigas conjecture - that quantum analogs of classically chaotic systems obey RMT - there was an explosion of activity utilizing level statistics in many different quantum systems. In nuclei the focus was verifying the range of applicability of RMT. Of particular interest was the effect of collectivity and of excitation energy on statistical properties. The effect of symmetry breaking on level statistics was examined and early predictions by Dyson were confirmed. The effect of symmetry breaking on the width distribution was also measured for the first time. Although heuristic arguments predicted no change from the PT distribution, experimentally there was a large deviation from the PT prediction. Later theoretical efforts were consistent with this result. The stringent conditions placed on the experiments - for eigenvalue tests the data need to be essentially perfect (few or no missing levels or mis assigned quantum numbers) - has limited the amount of suitable experimental data. The

  12. Electric quadrupole strength in nuclei

    International Nuclear Information System (INIS)

    Kirson, M.W.

    1979-01-01

    Isoscalar electric quadrupole strength distributions in nuclei are surveyed, and it is concluded that the strength is shared, in most cases, roughly equally between low-lying transitions and the giant quadrupole state. The same is not true of the isovector case. A simple extension of the schematic model gives a remarkably successul description of the data, and emphasizes the vital importance of the coupling between high-lying and low-lying quadrupole modes. The standadrd simple representation of the giant quadrupole resonance as produced by operating on the nuclear ground state with the quadrupole transition operator is not applicable to the isoscalar case. It is suggested that giant resonances fall into broad classes of similar states, with considerable qualitative differences between the distinct classes. (author)

  13. Structures of exotic nuclei

    International Nuclear Information System (INIS)

    Hamilton, J.H.

    1987-01-01

    Discoveries of many different types of nuclear shape coexistence are being found at both low and high excitation energies throughout the periodic table, as documented in recent reviews. Many new types of shape coexistence have been observed at low excitation energies, for examples bands on more than four different overlapping and coexisting shapes are observed in 185 Au, and competing triaxial and prolate shapes in 71 Se and 176 Pt. Discrete states in super-deformed bands with deformations β 2 ∼ 0.4-0.6, coexisting with other shapes, have been seen to high spin up to 60ℎ in 152 Dy, 132 Ce and 135 Nd. Super-deformed nuclei with N and Z both around 38 and around Z = 38, N ≥ 60. These data led to the discovery of new shell gaps and magic numbers of 38 for N and Z and 60 for N but now for deformed shapes. Marked differences in structure are observed at spins of 6 to 20 in nuclei in this region, which differ by only two protons; for example, 68 Ge and 70 Se. The differences are thought to be related to the competing shell gaps in these nuclei

  14. Elusive active galactic nuclei

    Science.gov (United States)

    Maiolino, R.; Comastri, A.; Gilli, R.; Nagar, N. M.; Bianchi, S.; Böker, T.; Colbert, E.; Krabbe, A.; Marconi, A.; Matt, G.; Salvati, M.

    2003-10-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically `elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive active galactic nuclei (AGN) in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 1024 cm-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical narrow-line region. Elusive AGN may contribute significantly to the 30-keV bump of the X-ray background.

  15. Investigation of nuclei near N = 82 and Z = 64 VIA radioactive decay of high-spin isomers

    International Nuclear Information System (INIS)

    Toth, K.S.

    1979-01-01

    An island of very high spin isomers was found recently in neutron-deficient Gd-Lu nuclei near the N = 82 closed shell in (H.I.,xn) measurements. This exciting discovery has led to a large number of experiments trying to identify the structures of these isomers and the nuclei in which they occur. These attempts have been helped in many instances by available spectroscopic information at low excitation energies. A systematic investigation of the low-lying structure of nuclei near N = 82 and Z greater than or equal to 64 was carried out. Heavy-ion beams were used to produce proton-rich isotopes which were then transported, with the use of gas-jet systems, to shielded areas where singles and coincidence γ-ray measurements could be made. Earlier investigations dealt with the decay of terbium ( 146-149 Tb) and dysprosium ( 147-152 Dy) nuclei. During the past two years the research program was extended to holmium nuclides (A less than or equal to 152) produced in 10 B bombardments of samarium. Two new isotopes, 149 Ho and 148 Ho, were identified. The decay data of 21-s 149 Ho supplement in-beam results and locate the hg/ 2 neutron state in 149 Dy to be at 1091 keV. The most intense γ-ray associated with 9-s 148 Ho has an energy of 1688 keV. It is possibly the first-excited to ground-state transition in 148 Dy. Recent in-beam measurements have shown that the first-excited state in 146 Gd is, unespectedly, 3 - in contrast to doubly evenN = 82 nuclei below gadolinium where it is 2 + . It would be interesting to determine whether the 1688-keV level in 148 Dy, the next nucleus in this isotonic series, is 2reverse arrow or 3 - in character. 12 references

  16. Double charge exchange of pions on nuclei

    International Nuclear Information System (INIS)

    Dzhibuti, R.I.; Kezerashvili, R.Y.

    1985-01-01

    An analysis is made of the results of experimental and theoretical studies during the last ten years of a unique process: double charge exchange of pions on nuclei. On the one hand, the commissioning of meson factories and the use of new and more accurate experimental methods have led to the accumulation of rich and reliable material for not only light but also medium and heavy nuclei. On the other hand, the development and application of new microscopic theoretical approaches have led to a deepening of our ideas about the mechanism of these exotic reactions at low, intermediate, and high energies. The currently existing methods of theoretical investigation and all possible reaction mechanisms are considered. Particular attention is devoted to double charge exchange of pions on the lightest nuclei, for the theoretical description of which it is possible to use the well-developed methods for investigating few-particle systems. The experimental investigations of double-isobar analog and nonanalog transitions in the reaction of double charge exchange are systematized

  17. Development of an ion guide coupled to an on-line isotope separation system on Sara. Identification and study of isospin exotic nuclei at Isolde and Sara

    International Nuclear Information System (INIS)

    Bouldjedri, A.

    1992-06-01

    This work is concerned with the study of exotic nuclei located on both sides of the stability-line and known as neutron rich and neutron deficient respectively. For the former, produced by alpha particle-induced fission, an on-line isotope separation with an ion guide (IGISOL) has been developed and submitted to several off-line and on-line optimization tests showing capacity to spectroscopic studies. In the case of neutron deficient nuclei near the magicity Z=82, 182 Tl(3s) has been identified and its decaying modes and those of 183 Tl ground state, studied, using the on-line separator ISOLDE. On the other hand, the β decay of 172,175 Ir produced in 32 S induced reaction is studied using a helium jet system on the SARA accelerator. Existence of isomers is derived from half-lives measurements

  18. Nuclei transmutation by collisions with fast hadrons and nuclei

    International Nuclear Information System (INIS)

    Strugalski, Z.; Strugalska-Gola, E.; Drzymala, A.

    1998-01-01

    Atomic nuclei change their mass- and charge-numbers if bombarded by fast hadrons and nuclei; the transmutation appears as a complicated process. It proceeds in a definite way - through a few stages or phases. Adequate identification of the nucleons and light nuclear fragments emitted and evaporated in a hadron-nucleus or nucleus-nucleus collisions and in the collision-induced intranuclear reactions allows one to estimate quantitatively the nuclei transmutations in the various stages (phases) of the process

  19. Anomalous carbon nuclei

    International Nuclear Information System (INIS)

    Gasparian, A.P.

    1984-01-01

    Results are presented from a bubble chamber experiment to search for anomalous mean free path (MFP) phenomena for secondary multicharged fragments (Zsub(f)=5 and 6) of the beam carbon nucleus at 4.2 GeV/c per nucleon. A total of 50000 primary interactions of carbon with propane (C 3 H 8 ) were created. Approximately 6000 beam tragments with charges Zsub(f)=5 and 6 were analyzed in detail to find out an anomalous decrease of MFP. The anomaly is observed only for secondary 12 C nuclei

  20. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2001-01-01

    The present collection of letters from JINR, Dubna, contains eight separate records on the interaction of high energy Λ 6 He hypernuclear beams with atomic nuclei, the position-sensitive detector of a high spatial resolution on the basis of a multiwire gas electron multiplier, pseudorapidity hadron density at the LHC energy, high precision laser control of the ATLAS tile-calorimeter module mass production at JINR, a new approach to ECG's features recognition involving neural network, subcriticity of a uranium target enriched in 235 U, beam space charge effects in high-current cyclotron injector CI-5, a homogeneous static gravitational field and the principle of equivalence

  1. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  2. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2000-01-01

    The present collection of letters from JINR, Dubna, contains six separate records on the DELPHI experiment at LEP, the Fermi-surface dynamics of rotating nuclei, production of large samples of the silica dioxide aerogel in the 37-litre autoclave and test of its optical properties, preliminary radiation resource results on scintillating fibers, a new algorithm for the direct transformation method of time to digital with the high time resolution and development and design of analogue read-out electronics for HADES drift chamber system

  3. Cumulation of light nuclei

    International Nuclear Information System (INIS)

    Baldin, A.M.; Bondarev, V.K.; Golovanov, L.B.

    1977-01-01

    Limit fragmentation of light nuclei (deuterium, helium) bombarded with 8,6 GeV/c protons was investigated. Fragments (pions, protons and deuterons) were detected within the emission angle 50-150 deg with regard to primary protons and within the pulse range 150-180 MeV/c. By the kinematics of collision of a primary proton with a target at rest the fragments observed correspond to a target mass upto 3 GeV. Thus, the data obtained correspond to teh cumulation upto the third order

  4. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  5. Complex fragment emission from hot compound nuclei

    International Nuclear Information System (INIS)

    Moretto, L.G.

    1986-03-01

    The experimental evidence for compound nucleus emission of complex fragments at low energies is used to interpret the emission of the same fragments at higher energies. The resulting experimental picture is that of highly excited compound nuclei formed in incomplete fusion processes which decay statistically. In particular, complex fragments appear to be produced mostly through compound nucleus decay. In the appendix a geometric-kinematic theory for incomplete fusion and the associated momentum transfer is outlined. 10 refs., 19 figs

  6. Soft radiative strength in warm nuclei

    International Nuclear Information System (INIS)

    Becker, J A; Bernstein, L A; Garrett, P E; Nelson, R O; Schiller, A; Voinov, A; Agvaanluvsan, U; Algin, E; Belgya, T; Chankova, R; Guttormsen, M; Mitchell, G E; Rekstad, J; Siem, S

    2004-01-01

    Unresolved transitions in the nuclear γ-ray cascade produced in the decay of excited nuclei are best described by statistical concepts: a continuous radiative strength function (RSF) and level density yield mean values of transition matrix elements. Data on the soft (E γ < 3-4 MeV) RSF for transitions between warm states (i.e. states several MeV above the yrast line) have, however, remained elusive

  7. Shell closures, loosely bound structures, and halos in exotic nuclei

    International Nuclear Information System (INIS)

    Saxena, G.; Singh, D.

    2013-01-01

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  8. Shell closures, loosely bound structures, and halos in exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Singh, D. [University of Rajasthan, Department of Physics (India)

    2013-04-15

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  9. Effective interactions and coupling schemes in nuclei

    International Nuclear Information System (INIS)

    Talmi, I.

    1994-01-01

    Eigenstates of the shell model are obtained by diagonalization of the Hamiltonian submatrix defined by a given shell model subspace. Matrix elements of the effective nuclear interaction can be determined from experiment in a consistent way. This approach was introduced in 1956 with the 38 Cl- 40 K spectra, has been applied in many cases and its latest success is in the s, d shell. This way, general features of the effective interaction have been determined. The T=1 interaction is diagonal in the seniority scheme as clearly demonstrated in proton 1g 9/2 n and 1h 11/2 n configurations and in the description of semimagic nuclei by generalized seniority. Apart from a strong and attractive pairing term, T=1 interactions are repulsive on the average. The T=0 interaction is attractive and is the origin of the central potential well in which nucleons are bound. It breaks seniority in a major way leading to deformed nuclei and rotational spectra. Such an interaction may be approximated by a quadrupole-quadrupole interaction which is the basis of the interacting boson model. Identical nucleons with pairing and quadrupole interactions cannot be models of actual nuclei. Symmetry properties of states with maximum T are very different from those of ground states of actual nuclei. The T=1 interaction between identical nucleons cannot be approximated by pairing and quadrupole interactions. The rich variety of nuclear spectra is due to the competition between seniority conserving T=1 interactions and the T=0 quadrupole interaction between protons and neutrons. (orig.)

  10. Exotic nuclei and radioactive beams

    International Nuclear Information System (INIS)

    Chomaz, P.

    1996-01-01

    The Nuclei called exotic are all the nuclei that it is necessary to recreate in laboratory to study them. Their life time is too short -in relation to earth age- for it remains enough on earth. The researchers are going to have at their s disposal at GANIL (Caen) with the S.P.I.R.A.L. project, exotic nuclei beams and will study new kinds of nuclear reactions to better understand the atom nucleus. (N.C.). 2 refs., 9 figs

  11. Nuclear structure around doubly-magic nuclei: lifetime measurements in the vicinity of 68Ni and search for isomers around 100Sn

    International Nuclear Information System (INIS)

    Celikovic, Igor

    2013-01-01

    In this thesis we investigated the structure of nuclei around 68 Ni as well as the production, separation and identification of proton-rich isotopes lying in the vicinity of the doubly-magic 100 Sn nucleus.In the first part, we discuss the evolution of collectivity and the interplay between collective and single-particle degrees of freedom in nuclei around 68 Ni. We measured lifetimes in Zn isotopes around N = 40 produced in 238 U + 70 Zn deep-inelastic collisions at GANIL. We used a plunger device and the recoil-distance Doppler-shift method. The nuclei of interest were identified by the VAMOS spectrometer and the γ-rays with the EXOGAM array. The reduced electromagnetic transitions probabilities were extracted from the lifetimes. Several transitions and lifetimes are reported for the first time. The experimental results are discussed in the framework of shell model calculations. In the second part, the partial conservation of seniority in the g 9/2 shell and its influence on one-particle transfer is discussed. The third part presents the analysis of an in-beam test performed at RIKEN (Japan) to evaluate two settings of the BigRIPS separator for optimizing the production and selection of 100 Sn. This study has been used to setup our subsequent experiment, dedicated to the measurement of the Gamow-Teller strength in the decay of 100 Sn, to the mapping of the proton drip-line and the study of short-lived isomers in this mass region. Nuclei around 100 Sn were produced by fragmentation of a 345 MeV/u 124 Xe beam on a Be target. The production cross-sections of nuclei around 100 Sn were measured. The search for new isotopes and new isomers in all identified nuclei is presented. (author) [fr

  12. Theory of magic nuclei

    International Nuclear Information System (INIS)

    Nosov, V.G.; Kamchatnov, A.M.

    A consistent theory of the shell and magic oscillations of the masses of spherical nuclei is developed on the basis of the Fermi liquid concept of the energy spectrum of nuclear matter. A ''magic'' relationship between the system's dimensions and the limiting momentum of the quasi-particle distribution is derived; an integer number of the de Broglie half-waves falls on the nuclear diameter. An expression for the discontinuity in the nucleon binding energy in the vicinity of a magic nucleus is obtained. The role of the residual interaction is analyzed. It is shown that the width of the Fermi-surface diffuseness due to the residual interaction is proportional to the squared vector of the quasi-particle orbital angular momentum. The values of the corresponding proportionality factors (the coupling constant for quasi particles) are determined from the experimental data for 52 magic nuclei. The rapid drop of the residual interaction with increasing nuclear size is demonstrated. (7 figures, 3 tables) (U.S.)

  13. Stability of superheavy nuclei

    Science.gov (United States)

    Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

    2018-03-01

    The potential-energy surfaces of an extended set of heavy and superheavy even-even nuclei with 92 ≤Z ≤126 and isospins 40 ≤N -Z ≤74 are evaluated within the recently developed Fourier shape parametrization. Ground-state and decay properties are studied for 324 different even-even isotopes in a four-dimensional deformation space, defined by nonaxiality, quadrupole, octupole, and hexadecapole degrees of freedom. Nuclear deformation energies are evaluated in the framework of the macroscopic-microscopic approach, with the Lublin-Strasbourg drop model and a Yukawa-folded mean-field potential. The evolution of the ground-state equilibrium shape (and possible isomeric, metastable states) is studied as a function of Z and N . α -decay Q values and half-lives, as well as fission-barrier heights, are deduced. In order to understand the transition from asymmetric to symmetric fission along the Fm isotopic chain, the properties of all identified fission paths are investigated. Good agreement is found with experimental data wherever available. New interesting features about the population of different fission modes for nuclei beyond Fm are predicted.

  14. Diffractive production off nuclei-shadow of hadronic bremsstrahlung

    International Nuclear Information System (INIS)

    Bialas, A.; Czyz, W.

    1974-01-01

    Diffractive production on nuclei is calculated using as an input a specific model for diffractive production on nucleons. In this model diffractive production is described as a shadow of non-diffractive multiple production of particles. The mechanism for non-diffractive production is taken to be hadronic bremsstrahlung of independently produced clusters. It is shown that such a model naturally explains the strikingly simple pattern of absorption observed in coherent production on nuclei. Possible generalizations of these results are indicated. (author)

  15. Physics with Heavy Neutron Rich Ribs at the Hribf

    Science.gov (United States)

    Radford, David

    2002-10-01

    The Holifield Radioactive Ion Beam Facility at the Oak Ridge National Laboratory has recently produced the world's first post-accelerated beams of heavy neutron-rich nuclei. B(E2;0^+ arrow 2^+) values for neutron-rich ^126,128Sn and ^132,134,136Te isotopes have been measured by Coulomb excitation of radioactive ion beams in inverse kinematics. The results for ^132Te and ^134Te (N=80,82) show excellent agreement with systematics of lighter Te isotopes, but the B(E2) value for ^136Te (N=84) is unexpectedly small. Single-neutron transfer reactions leading to ^135Te were identified using a ^134Te beam on ^natBe and ^13C targets at energies just above the Coulomb barrier. The use of the Be target provided an unambiguous signature for neutron transfer through the detection of two correlated α particles, arising from the breakup of unstable ^8Be. The results of these experiments will be discussed, togther with plans for future experiments with these heavy n-rich RIBs.

  16. Electron scattering off nuclei

    International Nuclear Information System (INIS)

    Gattone, A.O.

    1989-01-01

    Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author) [es

  17. Antideuteron annihilation on nuclei

    International Nuclear Information System (INIS)

    Cugnon, J.

    1992-01-01

    An investigation of antideuteron annihilation on nuclei within an intranuclear cascade (INC) model is presented. Two models are set up to describe the annihilation itself, which either implies the antideuteron as a whole and occurs at a single point, or which may be considered as two independent nucleon-antinucleon annihilation occurring at different points and different times. Particular attention is paid to the energy transferred from the pions issued from the annihilation to the nuclear system and to the possibility of having a multifragmentation of the target. The latter feature is investigated within a percolation model. The pion distribution and the energy distribution are also discussed. Predictions of proton multiplicity distributions are compared with experiment. (orig.)

  18. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2002-01-01

    The present collection of letters from JINR, Dubna, contains ten separate records on Wien filter using in exploring on low-energy radioactive nuclei, memory effects in dissipative nucleus-nucleus collision, topological charge and topological susceptibility in connection with translation and gauge invariance, solutions of the multitime Dirac equation, the maximum entropy technique. System's statistical description, the charged conductor inside dielectric. Solution of boundary condition by means of auxiliary charges and the method of linear algebraic equations, optical constants of the TGS single crystal irradiated by power pulsed electron beam, interatomic pair potential and n-e amplitude from slow neutron scattering by noble gases, the two-coordinate multiwire proportional chamber of the high spatial resolution and neutron drip line in the region of O-Mg isotopes

  19. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2000-01-01

    The present collection of letters from JINR, Dubna, contains seven separate records on the integral representation for structure functions and target mass effects, multiscale properties of DNA primary structure including cross-scale correlations, dissipative evolution of the elementary act, the fine structure of the M T =1 Gamow-Teller resonance in 147g Tb→ 147 Gd β + /EC decay, the behaviour of the TVO temperature sensors in the magnetic fields, a fast method for searching for tracks in multilayer drift chambers of HADES spectrometer, a novel approach to particle track etching including surfactant enhanced control of pore morphology, azimuthal correlations of secondary particles in 32 S induced interactions with Ag(Br) nuclei at 4.5 GeV/ c/ nucleon

  20. Pulsars: gigantic nuclei

    International Nuclear Information System (INIS)

    Xu, Renxin

    2011-01-01

    What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the gigantic nucleus speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction. (author)

  1. Pion production in nuclei

    International Nuclear Information System (INIS)

    Afnan, I.R.; Thomas, A.W.

    1976-01-01

    A method has been suggested for relating μ-capture in nuclei to pion absorption through partially conserved axial vector current hypothesis. The success of the method relies heavily on the knowledge of the pion absorption amplitude at a momentum transfer equal to the μ-meson mass. That is we need to know the pion absorption amplitude off the mass-shell. The simplest nucleus for which this suggestion can be examined is μ-capture in deuterium. The Koltum-Reitan model is used to determine the pion absorption amplitude off the mass shell. In particular the senstivity of this off-mass-shell extrapolution to details of the N-N interaction is studied. (author)

  2. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    1998-01-01

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors)

  3. IBA in deformed nuclei

    International Nuclear Information System (INIS)

    Casten, R.F.; Warner, D.D.

    1982-01-01

    The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for 168 Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong β → γ transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the β → γ transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ΔK=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics

  4. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.

  5. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... Nuclei in the actinide chain and beyond are prone to fission owing to ... mass nuclei are typically more difficult, because the intensity is .... j15/2 neutron alignments in a region where shell stablization effects are crucial.

  6. Problem of ''deformed'' superheavy nuclei

    International Nuclear Information System (INIS)

    Sobiczewski, A.; Patyk, Z.; Muntian, I.

    2000-08-01

    Problem of experimental confirmation of deformed shapes of superheavy nuclei situated in the neighbourhood of 270 Hs is discussed. Measurement of the energy E 2+ of the lowest 2+ state in even-even species of these nuclei is considered as a method for this confirmation. The energy is calculated in the cranking approximation for heavy and superheavy nuclei. The branching ratio p 2+ /p 0+ between α decay of a nucleus to this lowest 2+ state and to the ground state 0+ of its daughter is also calculated for these nuclei. The results indicate that a measurement of the energy E 2+ for some superheavy nuclei by electron or α spectroscopy is a promising method for the confirmation of their deformed shapes. (orig.)

  7. Quarks in Few Body Nuclei

    Directory of Open Access Journals (Sweden)

    Holt Roy J.

    2016-01-01

    Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  8. Study of the elastic scattering and of the (p,n) charge exchange reaction with neutron-rich light exotic beams; Etude de la diffusion elastique et de la reaction d`echange de charge (p,n) avec des faisceaux exotiques legers riches en neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cortina Gil, D.

    1996-07-05

    We have measured at GANIL, with the high resolution spectrometer SPEG, the elastic scattering of several neutron rich secondary beams ({sup 6}He, {sup 10}Be and {sup 11}Be) on a polypropylene target and the charge exchange reaction p({sup 6}He, {sup 6}Li)n. These exotic beams were produced by nuclear fragmentation and re-focalized with the SISSI device (superconducting solenoids). The signature of a halo structure in these nuclei has been analysed. Special attention has been paid to several aspects of the associated calculations namely, the proton and neutron density distributions and the small binding energy for the last nucleons in these exotic nuclei. Break-up mechanisms are seen to play an important role in these nuclei. 100 refs.

  9. Unexpected high-energy γ emission from decaying exotic nuclei

    Directory of Open Access Journals (Sweden)

    A. Gottardo

    2017-09-01

    Full Text Available The N=52 Ga83 β decay was studied at ALTO. The radioactive 83Ga beam was produced through the ISOL photofission technique and collected on a movable tape for the measurement of γ-ray emission following β decay. While β-delayed neutron emission has been measured to be 56–85% of the decay path, in this experiment an unexpected high-energy 5–9 MeV γ-ray yield of 16(4% was observed, coming from states several MeVs above the neutron separation threshold. This result is compared with cutting-edge QRPA calculations, which show that when neutrons deeply bound in the core of the nucleus decay into protons via a Gamow–Teller transition, they give rise to a dipolar oscillation of nuclear matter in the nucleus. This leads to large electromagnetic transition probabilities which can compete with neutron emission, thus affecting the β-decay path. This process is enhanced by an excess of neutrons on the nuclear surface and may thus be a common feature for very neutron-rich isotopes, challenging the present understanding of decay properties of exotic nuclei.

  10. Possibilities at LAMPF for studying nuclei of astrophysical interest

    International Nuclear Information System (INIS)

    Talbert, W.L. Jr.; Bunker, M.E.

    1985-01-01

    Nuclear data needs in astrophysics range from neutron capture cross sections of a number of stable or near-stable nuclei to decay and neutron binding-energy data for highly neutron-rich nuclei. LAMPF has the potential to contribute significantly to these needs. The new Los Alamos Neutron Scattering Center (LANSCE, aka WNR/PSR) offers world-class capabilities for neutron capture studies up to an MeV or so. The study of nuclei far from stability could be extended into some regions of astrophysical interest using a proposed He-jet coupled mass separator system with a target/production chamber in the LAMPF beam stop area. Specific examples of possible studies at each facility are presented

  11. Cumulative processes and quark distribution in nuclei

    International Nuclear Information System (INIS)

    Kondratyuk, L.; Shmatikov, M.

    1984-01-01

    Assuming existence of multiquark (mainly 12q) bags in nuclei the spectra of cumulative nucleons and mesons produced in high-energy particle-nucleus collisions are discussed. The exponential form of quark momentum distribution in 12q-bag (agreeing well with the experimental data on lepton-nucleus interactions at large q 2 ) is shown to result in quasi-exponential distribution of cumulative particles over the light-cone variable αsub(B). The dependence of f(αsub(B); psub(perpendicular)) (where psub(perpendicular) is the transverse momentum of the bag) upon psub(perpendicular) is considered. The yields of cumulative resonances as well as effects related to the u- and d-quark distributions in N > Z nuclei being different are dicscussed

  12. Imaging of Nuclear Fragmentation in Nuclear Track Emulsion Relativistic Nuclei

    International Nuclear Information System (INIS)

    Zarubina, I.G. JINR

    2011-01-01

    The method of nuclear track emulsion provides a uniquely complete observation of multiple fragment systems produced in dissociation of relativistic nuclei. The most valuable events of coherent dissociation of nuclei in narrow jets of light and the lightest nuclei with a net charge as in the initial nucleus, occurring without the production of fragments of the target nuclei and mesons (the so-called w hite s tars), comprise a few percent among the observed interactions. The data on this phenomenon are fragmented, and the interpretation is not offered. The dissociation degree of light O, Ne, Mg and Si, and as well as heavy Au, Pb and U nuclei may reach a complete destruction to light and the lightest nuclei and nucleons, resulting in cluster systems of an unprecedented complexity. Studies with relativistic neutron-deficient nuclei have special advantages due to more complete observations. An extensive collection of macro videos of such interactions in nuclear track emulsion gathered by the Becquerel collaboration is presented

  13. Direct mass measurements of 100Sn and magic nuclei near the N=Z line

    International Nuclear Information System (INIS)

    Chartier, M.

    1996-01-01

    The masses of nuclei far from stability are of particular interest in nuclear structure studies, and many methods of varying precision have been developed to undertake their measurement. A direct time of flight technique in conjunction with the SPEG spectrometer at GANIL has been extended to the mass measurement of proton-rich nuclei near N = Z line in the mass region A ≅ 60-80 known to provide input for astrophysical modelling of the rp-process and information relevant to the nuclear structure in a region of high deformation. The radioactive beams were produced via the fragmentation of a 78 Kr beam on a nat Ni target, using the new SISSI device. A purification method based on the stripping of the secondary ions was successfully used for the first time, and the masses of 70 Se and 71 Se were measured. In order to improve the mass resolution for heavier nuclei, another method using the second cyclotron of GANIL (CSS2) as a high resolution spectrometer has been developed. An experiment aimed at measuring the masses of A 100 isobars in the vicinity of the doubly magic nucleus 100 Sn was successfully performed, using this original technique. Secondary ions of 100 Ag, 100 Cd, 100 In and 100 Sn produced via fusion-evaporation reaction 50 Cr + 58 Ni and simultaneously accelerated in the CSS2 cyclotron. The mass of 100 Cd and, for the first time, the masses of 100 Sn were determined directly with respect to the reference mass of 100 Ag. These results have been compared to various theoretical predictions and open the discussion on considerations of spin-isospin symmetry. (author)

  14. Proton-rich nuclear statistical equilibrium

    International Nuclear Information System (INIS)

    Seitenzahl, I.R.; Timmes, F.X.; Marin-Lafleche, A.; Brown, E.; Magkotsios, G.; Truran, J.

    2008-01-01

    Proton-rich material in a state of nuclear statistical equilibrium (NSE) is one of the least studied regimes of nucleosynthesis. One reason for this is that after hydrogen burning, stellar evolution proceeds at conditions of an equal number of neutrons and protons or at a slight degree of neutron-richness. Proton-rich nucleosynthesis in stars tends to occur only when hydrogen-rich material that accretes onto a white dwarf or a neutron star explodes, or when neutrino interactions in the winds from a nascent proto-neutron star or collapsar disk drive the matter proton-rich prior to or during the nucleosynthesis. In this Letter we solve the NSE equations for a range of proton-rich thermodynamic conditions. We show that cold proton-rich NSE is qualitatively different from neutron-rich NSE. Instead of being dominated by the Fe-peak nuclei with the largest binding energy per nucleon that have a proton-to-nucleon ratio close to the prescribed electron fraction, NSE for proton-rich material near freezeout temperature is mainly composed of 56Ni and free protons. Previous results of nuclear reaction network calculations rely on this nonintuitive high-proton abundance, which this Letter explains. We show how the differences and especially the large fraction of free protons arises from the minimization of the free energy as a result of a delicate competition between the entropy and nuclear binding energy.

  15. Transfer reaction studies in the region of heavy and superheavy nuclei at SHIP

    Energy Technology Data Exchange (ETDEWEB)

    Heinz, S; Comas, V; Hofmann, S; Ackermann, D; Heredia, J; Hessberger, F P; Khuyagbaatar, J; Kindler, B; Lommel, B; Mann, R, E-mail: s.heinz@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2011-02-01

    We studied multi-nucleon transfer reactions in the region of heavy and superheavy nuclei. The goal was to investigate these reactions as possibility to create new superheavy neutron-rich isotopes, which cannot be produced in fusion reactions. The experiments have been performed at the velocity filter SHIP at GSI. At SHIP we can detect and identify the heavy, target-like, transfer products. Due to the low background at the focal plane detector and the isotope identification via radioactive decays, the setup allows to reach an upper cross-section limit of 10 pb/sr within one day of beamtime. We investigated the systems {sup 58,64}Ni + {sup 207}Pb and {sup 48}Ca + {sup 248}Cm at beam energies below and up to 20% above the Coulomb barrier. At all energies we observed a massive transfer of protons and neutrons, where transfer products with up to eight neutrons more than the target nucleus could be identified.

  16. Experimental research of isospin and spin exotic nuclei with an ion guide and γ multidetectors

    International Nuclear Information System (INIS)

    Astier, A.

    1992-04-01

    This work is concerned with nuclear studies of isospin and spin exotic nuclei by two complementary approaches: on-line radioactivity and fusion-evaporation reactions. An ion guide coupled to the SARA accelerator allowed the study of very refractory and short lived (down to 1 ms) elements. Using the 238 U (α 40 MeV, f) reaction to produce very neutron-rich radioisotopes, all mass chains from A=96 to 122 have been scanned by conventional nuclear spectroscopy. More than 60 production yields have been measured. The comparison of proton and α induced fission yields shows the predominance of symmetric fission around A=115 for α beam. The collective high spin states structures observed in the A=190 mass region are studied with different γ multidetectors

  17. Clusters in Nuclei. Vol. 2

    International Nuclear Information System (INIS)

    Beck, Christian

    2012-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  18. Clusters in Nuclei. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Christian (ed.) [Strasbourg Univ. (France). Inst. Pluridiciplinaire Hubert Curien

    2012-07-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  19. K-bar-mesic nuclei

    International Nuclear Information System (INIS)

    Dote, Akinobu; Akaishi, Yoshinori; Yamazaki, Toshimitsu

    2005-01-01

    New nuclei 'K-bar-Mesic Nuclei' having the strangeness are described. At first it is shown that the strongly attractive nature of K-bar N interaction is reasoned inductively from consideration of the relation between Kaonic hydrogen atom and Λ (1405) which is an excited state of hyperon Λ. The K-bar N interactions are reviewed and summarized into three categories: 1. Phenomenological approach with density dependent K-bar N interaction (DD), relativistic mean field (RMF) approach, and hybrid of them (RMF+DD). 2. Boson exchange model. 3. Chiral SU(3) theory. The investigation of some light K-bar-nuclei by Akaishi and Yamazaki using phenomenological K-bar N interaction is explained in detail. Studies by antisymmetrized molecular dynamics (AMD) approach are also presented. From these theoretical researches, the following feature of K-bar-mesic nuclei are revealed: 1) Ground state is discrete and bound by 100 MeV or more. 2) Density is very high in side the K-bar-mesic nuclei. 3) Strange structures develop which are not seen in ordinary nuclei. Finally some recent experiments to explore K-bar-mesic nuclei are reviewed. (S. Funahashi)

  20. Gamma-ray spectroscopy of nuclei near {sup 100}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Seweryniak, D; Nyberg, J; Fahlander, C [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Cederwall, B; Norline, L; Johnson, A; Kerek, A [Manne Siegbahn Inst. of Physics, Stockholm (Sweden); [Royal Inst. of Tech., Stockholm (Sweden); Adamides, E [National Centre for Scientific Research, Ag. Paraskevi, Attiki (Greece); Atac, A; Piiparinen, M; Sletten, G [Niels Bohr Inst., Copenhagen (Denmark); Angelis, G de [Laboratori Nazionali di legnaro (Italy); Grawe, H; Schubart, R [Hahn-Meitner-Institut Berlin GmbH (Germany); Ideguchi, E; Mitarai, S [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Julin, R; Juutinen, S; Tormanen, S; Virtanen, A [Jyvaeskylae Univ. (Finland). Dept. of Physics; Karczmarczyk, W; Kownacki, J [Warsaw Univ. (Poland)

    1992-08-01

    Proton rich nuclei close to {sup 100}Sn have been investigated in an in-beam {gamma}-ray spectroscopic study using the NORDBALL detector array, including arrays of charged particle and neutron detectors. Excited states were identified for the first time in {sup 102}In, {sup 106,107,108}Sb and tentatively in {sup 108,109}Te. The nucleus {sup 110}Te was also populated and studied for the first time in an in-beam experiment. (author). 4 figs.

  1. Monopole transitions in hot nuclei

    International Nuclear Information System (INIS)

    Sujkowski, Z.

    1994-01-01

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs

  2. Monopole transitions in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.

  3. Electron scattering for exotic nuclei

    International Nuclear Information System (INIS)

    Suda, T.

    2013-01-01

    An electron scattering facility is under construction in RIKEN RI Beam Factory, Japan, which is dedicated to the structure studies of short-lived nuclei. This is the world's first and currently only facility of its type. The construction is nearly completed, and the first electron scattering experiment off short-lived nuclei will be carried out in the beginning of next year. The charge density distributions of short-lived nuclei will be precisely determined by elastic electron scattering for the first time. Physics pursued at this facility including future perspectives are explained

  4. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model...

  5. Nucleon-nucleon momentum correlation function for light nuclei

    International Nuclear Information System (INIS)

    Ma, Y.G.; Cai, X.Z.; Chen, J.G.; Fang, D.Q.; Guo, W.; Liu, G.H.; Ma, C.W.; Ma, E.J.; Shen, W.Q.; Shi, Y.; Su, Q.M.; Tian, W.D.; Wang, H.W.; Wang, K.; Wei, Y.B.; Yan, T.Z.

    2007-01-01

    Nucleon-nucleon momentum correlation function have been presented for nuclear reactions with neutron-rich or proton-rich projectiles using a nuclear transport theory, namely Isospin-Dependent Quantum Molecular Dynamics model. The relationship between the binding energy of projectiles and the strength of proton-neutron correlation function at small relative momentum has been explored, while proton-proton correlation function shows its sensitivity to the proton density distribution. Those results show that nucleon-nucleon correlation function is useful to reflect some features of the neutron- or proton-halo nuclei and therefore provide a potential tool for the studies of radioactive beam physics

  6. The quest for novel modes of excitation in exotic nuclei

    Science.gov (United States)

    Paar, N.

    2010-06-01

    This paper provides an insight into several open problems in the quest for novel modes of excitation in nuclei with isospin asymmetry, deformation and finite-temperature characteristics in stellar environments. Major unsolved problems include the nature of pygmy dipole resonances, the quest for various multipole and spin-isospin excitations both in neutron-rich and proton drip-line nuclei mainly driven by loosely bound nucleons, excitations in unstable deformed nuclei and evolution of their properties with the shape phase transition. Exotic modes of excitation in nuclei at finite temperatures characteristic of supernova evolution present open problems with a possible impact in modeling astrophysically relevant weak interaction rates. All these issues challenge self-consistent many-body theory frameworks at the frontiers of on-going research, including nuclear energy density functionals, both phenomenological and constrained by the strong interaction physics of QCD, models based on low-momentum two-nucleon interaction Vlow-k and correlated realistic nucleon-nucleon interaction VUCOM, supplemented by three-body force, as well as two-nucleon and three-nucleon interactions derived from the chiral effective field theory. Joined theoretical and experimental efforts, including research with radioactive isotope beams, are needed to provide insight into dynamical properties of nuclei away from the valley of stability, involving the interplay of isospin asymmetry, deformation and finite temperature.

  7. Gluon density in nuclei

    International Nuclear Information System (INIS)

    Ayala, A.L.

    1996-01-01

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab

  8. Supersymmetry in nuclei

    CERN Document Server

    Jolie, J

    2002-01-01

    All the elementary particles that make up matter (as do quarks, electrons, neutrinos....) are fermions, the particles that convey the fundamental interactions (as do photons, gluons, W, Z...) are bosons. Composite particles are either bosons, or fermions according to the number of fermions they contain: if this number is even the particle is a boson, otherwise it is a fermion. According to this rule a proton is a fermion and the He sup 4 atom is a boson. Symmetry plays an important role in the standard model, a symmetry is a transformation that connect bosons with other bosons or fermions with other fermions. Supersymmetry associates a boson with a fermion or a fermion with a boson, in fact supersymmetry connects nuclei that are not generally considered as akin. Supersymmetry has just been observed in low energy levels of Gold sup 1 sup 9 sup 5 sup - sup 1 sup 9 sup 6 and Platinum sup 1 sup 9 sup 4 - sup 1 sup 9 sup 5 , it means that the description of these energy levels is simplified and can be made by a co...

  9. Supersymmetry in nuclei

    International Nuclear Information System (INIS)

    Jolie, J.

    2002-01-01

    All the elementary particles that make up matter (as do quarks, electrons, neutrinos....) are fermions, the particles that convey the fundamental interactions (as do photons, gluons, W, Z...) are bosons. Composite particles are either bosons, or fermions according to the number of fermions they contain: if this number is even the particle is a boson, otherwise it is a fermion. According to this rule a proton is a fermion and the He 4 atom is a boson. Symmetry plays an important role in the standard model, a symmetry is a transformation that connect bosons with other bosons or fermions with other fermions. Supersymmetry associates a boson with a fermion or a fermion with a boson, in fact supersymmetry connects nuclei that are not generally considered as akin. Supersymmetry has just been observed in low energy levels of Gold 195-196 and Platinum 194 - 195 , it means that the description of these energy levels is simplified and can be made by a common set of quantum numbers. (A.C.)

  10. Photon interactions with nuclei

    International Nuclear Information System (INIS)

    Thornton, S.T.; Sealock, R.M.

    1989-01-01

    This document is a progress report for DOE Grant No. FG05-89ER40501, A000. The grant began March, 1989. Our primary research effort has been expended at the LEGS project at Brookhaven National Laboratory. This report will summarize our present research effort at LEGS as well as data analysis and publications from previous experiments performed at SLAC. In addition the principal investigators are heavily involved in the CLAS collaboration in Hall B at CEBAF. We have submitted several letters of intent and proposals and have made commitments to construct experimental equipment for CEBAF. We expect our primary experimental effort to continue at LEGS until CEBAF becomes operational. This report will be divided into separate sections describing our progress at LEGS, SLAC, and CEBAF. We will also discuss our significant efforts in the education and training of both undergraduate and graduate students. Photon detectors are described as well as experiments on delta deformation in nuclei of quasielastic scattering and excitation of the delta by 4 He(e,e')

  11. Parity violation in nuclei

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1980-01-01

    A summary of parity violating effects in nuclei is given. Thanks to vigorous experimental and theoretical effort, it now appears that a reasonably well-defined value for the weak isovector π-nucleon coupling constant can be obtained. There is one major uncertainty in the analysis, namely the M2/E1 mixing ratio for the 2.79 MeV transition in 21 Ne. This quantity is virtually impossible to calculate reliably and must be measured. If it turns out to be much larger than 1, then a null result in 21 Ne is expected no matter what the weak interaction, so an experimental determination is urgently needed. The most promising approach is perhaps a measurement of the pair internal conversion coefficient. Of course, a direct measurement of a pure isovector case is highly desirable, and it is to be hoped that the four ΔT = 1 experiments will be pushed still further, and that improved calculations will be made for the 6 Li case. Nuclear parity violation seems to be rapidly approaching an interesting and useful synthesis

  12. Symmetries in nuclei

    International Nuclear Information System (INIS)

    Arima, A.

    2003-01-01

    (1) There are symmetries in nature, and the concept of symmetry has been used in art and architecture. The symmetry is evaluated high in the European culture. In China, the symmetry is broken in the paintings but it is valued in the architecture. In Japan, however, the symmetry has been broken everywhere. The serious and interesting question is why these differences happens? (2) In this lecture, I reviewed from the very beginning the importance of the rotational symmetry in quantum mechanics. I am sorry to be too fundamental for specialists of nuclear physics. But for people who do not use these theories, I think that you could understand the mathematical aspects of quantum mechanics and the relation between the angular momentum and the rotational symmetry. (3) To the specialists of nuclear physics, I talked about my idea as follows: dynamical treatment of collective motions in nuclei by IBM, especially the meaning of the degeneracy observed in the rotation bands top of γ vibration and β vibration, and the origin of pseudo-spin symmetry. Namely, if there is a symmetry, a degeneracy occurs. Conversely, if there is a degeneracy, there must be a symmetry. I discussed some details of the observed evidence and this correspondence is my strong belief in physics. (author)

  13. Collective excitations in nuclei

    International Nuclear Information System (INIS)

    Chomaz, Ph.

    1997-01-01

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author)

  14. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph

    1997-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.

  15. Nuclei at extreme conditions. A relativistic study

    Energy Technology Data Exchange (ETDEWEB)

    Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)

    2014-11-14

    The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.

  16. Particles and nuclei, letters

    International Nuclear Information System (INIS)

    2002-01-01

    The present collection of letters from JINR, Dubna, contains eight separate records on the role of the complanar emission of particles in nuclear interaction for E 0 >10 16 eV detected in the stratosphere, 10 B nucleus fragment yields, nuclear teleportation (proposal for an experiment), invisible 'glue' bosons in model field theory, calculation of the ionization differential effective cross sections in fast ion-atom collisions, interactions of ultracold neutrons near surface of solids, g factors as a probe for high-spin structure of neutron-rich Dy isotopes, search for periodicities in experimental data by the autoregressive model methods

  17. Spin Modes in Nuclei and Nuclear Forces

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Otsuka, Takaharu

    2011-01-01

    Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in 12 C and 14 C and an anomalous M1 transition in 17 C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by Δ excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

  18. Decay properties of nuclei close to Z = 108 and N = 162

    International Nuclear Information System (INIS)

    Dvorak, Jan

    2007-01-01

    The goal of the research conducted in the frame of this thesis was to investigate the decay properties of the nuclides 269-271 Hs and their daughters using an improved chemical separation and detection system. Shell stabilization was predicted in the region around Z=108 and N=162 in calculations, taking into account possible higher orders of deformations of the nuclei. The nucleus 270 Hs with a closed proton and a closed neutron deformed shell, was predicted to be ''deformed doubly magic''. Nuclei around 270 Hs can be produced only via fusion reactions at picobarn levels, resulting in a production rates of few atoms per day. Investigating short-lived nuclei using rapid chemical separation and subsequent on-line detection methods provides an independent and alternative means to electromagnetic on-line separators. Chemical separation of Hs in the form of HsO 4 provides an excellent tool to study the formation reactions and nuclear structure in this region of the chart of nuclides due to a high overall efficiency and a very high purification factor. The goal was accomplished, as element 108, hassium, was produced in the reaction 248 Cm( 26 Mg,xn) 274-x Hs and chemically isolated. After gas phase separation of HsO 4 , 26 genetically linked decay chains have been observed. These were attributed to decays of three different Hs isotopes produced in the 3-5n evaporation channels. The known decay chain of 269 Hs, the 5n evaporation product, serves as an anchor point, thus allowing the unambiguous assignment of the observed decay chains to the 5n, 4n, and 3n channels, respectively. Decay properties of five nuclei have been unambiguously established for the first time, including the one for the the doubly-magic nuclide 270 Hs. This hassium isotope is the next doubly magic nucleus after the well known 208 Pb and the first experimentally observed even-even nucleus on the predicted N=162 neutron shell. The observed decay properties provide strong indications for enhanced nuclear

  19. Dynamic polarization of radioactive nuclei

    International Nuclear Information System (INIS)

    Kiselev, Yu.F.; Lyuboshits, V.L.; )

    2001-01-01

    Radioactive nuclei, embedded into a frozen polarized proton target, atr proposed to polarize by means of some dynamic polarization methods. Angular distributions of γ-quanta emitted ny 22 Na(3 + ) in the cascade β-γ-radiation are calculated. It is shown that this distribution does not depend on the spin temperature sing at the Boltzmann distribution of populations among the Zeeman magnetic substates, whereas the tensor polarization of quadrupole nuclei, placed in the electric field of the crystal, causes the considerable sing dependence. The new method promises wide opportunities for the magnetic structure investigations as well as for the study of spin-spin interaction dynamics of rare nuclei in dielectrics. Physical-technical advantages and disadvantages of the given method are discussed for the polarization of heavy nuclei in the on-line implantation mode [ru

  20. The delta in nuclei. Experiments

    International Nuclear Information System (INIS)

    Roy-Stephan, M.

    1989-01-01

    Experimental aspects of the Δ excitation will be presented. The Δ excitation in nuclei will be compared to the free Δ excitation. Various probes will be reviewed and their specific features will be underlined [fr

  1. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Research Center for Electron-Photon Science, Tohoku University, 1-2-1 ... nuclei precisely determined by elastic scattering [1]. .... In order to fulfill these requirements, a window-frame shaped dipole magnet with a gap.

  2. Determination of the cross section for (n,p) reaction with producing short-lived nuclei on the 162,163Dy isotopes at 13.5 and 14.8 MeV

    International Nuclear Information System (INIS)

    Luo, Junhua; Feng, Zhifu; An, Li; Jiang, Li; He, Long

    2016-01-01

    Activation cross-sections for the 162 Dy(n,p) 162 Tb and 163 Dy(n,p) 163 Tb reactions have been measured by means of the activation technique and a coaxial HPGe γ-ray detector at 13.5 and 14.8 MeV. The fast neutrons were produced via the 3 H(d,n) 4 He reaction on Pd-300 neutron generator. The natural high-purity Dy 2 O 3 powder was used as target material. Theoretical excitation functions were calculated using the nuclear-reaction codes EMPIRE-3.2 Malta and TALYS-1.6 with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were also discussed and compared with some corresponding values found in the literature, with the comprehensive evaluation data in ENDF/B-VII.1 and JENDF-4.0 libraries, and with the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd–even effects taken into consideration. - Highlights: • The cross sections for the 162 Dy(n,p) 162 Tb and 163 Dy(n,p) 163 Tb have been measured. • 93 Nb(n,2n) 92m Nb was used as a monitor for neutron fluence. • Codes TALYS-1.6 and EMPIRE-3.2 Malta were used to model the reactions. • The results were compared with previous data. • Inconsistency with previous data and with model calculations are noted.

  3. Collisions between complex atomic nuclei

    International Nuclear Information System (INIS)

    Vaagen, J. S.

    1977-08-01

    The use of heavy ion accelerators in the study of nuclear structure and states is reviewed. The reactions discussed are the quasielastic reactions in which small amounts of energy and few particles are exchanged between the colliding nuclei. The development of heavy ion accelerators is also discussed, as well as detection equipment. Exotic phenomena, principally the possible existence of superheavy nuclei, are also treated. (JIW)

  4. Particles and nuclei in PANIC

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-07-15

    PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa.

  5. Particles and nuclei in PANIC

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    PANIC is the triennal International Conference on Particles and Nuclei, and judging from the latest PANIC, held in Kyoto from 20-24 April there is no need for panic yet. Faced with two pictures – one of nuclei described in nucleon and meson terms, and another of nucleons containing quarks and gluons – physicists are intrigued to know what new insights from the quark level can tell us about nuclear physics, or vice versa

  6. Investigation of copper nuclei

    International Nuclear Information System (INIS)

    Delfini, M.G.

    1983-01-01

    An extensive study has been performed on copper isotopes in the mass region A=63-66. The results of a precise measurement are presented on the properties of levels of 64 Cu and 66 Cu. They were obtained by bombarding the 63 Cu and 65 Cu nuclei with neutrons. The gamma spectra collected after capture of thermal, 2-keV, 24-keV neutrons have been analysed and combined to give a rather extensive set of precise level energies and gamma transition strengths. From the angular distribution of the gamma rays it is possible to obtain information concerning the angular momentum J of several low-lying states. The level schemes derived from such measurements have been used as a test for calculations in the framework of the shell model. The spectral distributions of eigenstates in 64 Cu for different configuration spaces are presented and discussed. In this study the relative importance of configurations with n holes in the 1f7/2 shell with n up to 16, are investigated. It is found that the results strongly depend on the values of the single-particle energies. The results of the spectral-distribution method were utilized for shell-model calculations. From the information obtained from the spectral analysis it was decided to adopt a configuration space which includes up to one hole in the 1f7/2 shell and up to two particles in the 1g9/2 shell. Further, restrictions on seniority and on the coupling of the two particles in the 1g9/2 orbit have been applied and their effects have been studied. It is found that the calculated excitation energies reproduce the measured values in a satisfactory way, but that some of the electromagnetic properties are less well in agreement with experimental data. (Auth.)

  7. Study on rotational bands in odd-odd nuclei 102,l04Nb by using PSM

    International Nuclear Information System (INIS)

    Dong Yongsheng; Hu Wentao; Feng Youliang; Wang Jinbao; Yu Shaoying; Shen Caiwan

    2012-01-01

    The Projected Shell Model (PSM) is used to study the low energy scheme of the neutron-rich normal-deformed isotopes of odd-odd nuclei 102,104 Nb. The quasiparticle configuration is assigned. The theoretical calculations of the energy band of 102,104 Nb could well reproduce the experimental data. It is shown that PSM is a valid method for studying the low energy scheme of heavy nuclei. (authors)

  8. Investigation of the halo structure of exotic nuclei by direct reactions in inverse kinematics

    International Nuclear Information System (INIS)

    Egelhof, Peter

    2003-01-01

    Neutron-rich light nuclei near or at the neutron drip line have attracted much attention in recent years since there is clear evidence that they reveal a qualitatively new type of nuclear structure, namely an extended distribution of valence neutrons surrounding a compact nuclear core. A brief overview is given on this halo phenomenon, and on the various methods, which gave first evidence for, and qualitative confirmation of our present picture on halo nuclei

  9. Signatures for quark clustering in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, C.E. [College of William and Mary, Williamsburg, VA (United States); Lassila, K.E. [Iowa State Univ., Ames, IA (United States)

    1994-04-01

    As a signature for the presence of quark clusters in nuclei, the authors suggest studying backward protons produced by electron scattering off deuterons and suggest a ratio that cancels out much of the detailed properties of deuterons or 6-quark clusters. The test may be viewed as a test that the short range part of the deuteron is still a 2-nucleon system. They make estimates to show how it fails in characteristic and significant ways if the two nucleons at short range coalesce into a kneaded 6-quark cluster.

  10. Signatures for quark clustering in nuclei

    International Nuclear Information System (INIS)

    Carlson, C.E.; Lassila, K.E.

    1994-01-01

    As a signature for the presence of quark clusters in nuclei, the authors suggest studying backward protons produced by electron scattering off deuterons and suggest a ratio that cancels out much of the detailed properties of deuterons or 6-quark clusters. The test may be viewed as a test that the short range part of the deuteron is still a 2-nucleon system. They make estimates to show how it fails in characteristic and significant ways if the two nucleons at short range coalesce into a kneaded 6-quark cluster

  11. Spectrin-like proteins in plant nuclei

    NARCIS (Netherlands)

    Ruijter, de N.C.A.; Ketelaar, T.; Blumenthal, S.S.D.; Emons, A.M.C.; Schel, J.H.N.

    2000-01-01

    We analysed the presence and localization of spectrin-like proteins in nuclei of various plant tissues, using several anti-erythrocyte spectrin antibodies on isolated pea nuclei and nuclei in cells. Western blots of extracted purified pea nuclei show a cross-reactive pair of bands at 220–240 kDa,

  12. Coulomb excitation of neutron-rich odd-$A$ Cd isotopes

    CERN Multimedia

    Reiter, P; Kruecken, R; Gernhaeuser, R A; Kroell, T; Leske, J; Marginean, N M

    We propose to study excited states in the odd-${A}$ isotopes $^{123,125,127}$Cd by ${\\gamma}$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to determine the B(E2) values connecting excited states with the ground state as well as the long-lived (11/2$^{-}$) isomer. The proposed study profits from the unique capability of ISOLDE to produce beams containing Cd in the ground state or in the isomeric state. Our recent results on the neutron-rich even-A Cd nuclei appear to show that these nuclei may possess some collectivity beyond that calculated by modern shell-model predictions. Beyond-mean-field calculations also predict these nuclei to be weakly deformed. These facets are surprising considering their proximity to the doubly magic $^{132}$Sn. Coulomb-excitation studies of odd-${A}$ Cd isotopes may give a unique insight into the deformation-driving roles played by different orbits in this region. Such studies of the onset of collectivity become especially important in light of recent...

  13. From heavy nuclei to super-heavy nuclei

    International Nuclear Information System (INIS)

    Theisen, Ch.

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  14. Complete destruction of heavy nuclei by hadrons and nuclei

    International Nuclear Information System (INIS)

    Tolstov, K.D.

    1980-01-01

    The total disintegration is considered of Ag and Pb nuclei and 4 He, 12 C nuclei With a momentum of 4.5 GeV/c per nucleon. It is shown that nucleons are mainly emitted, and there is no residual nUcleus the mass of which is comparable to that of the primary nucleus. The probability of total nucleus disintegration is considered as a function of projectile energy and the mass. The multiplicity, energy and emission angle of particles are considerred as well. It is shown that the density of nuclear matter in the overlap zone of colliding nuclei exceeds the usual one by a factor of approximately 4. A comparison is made with interaction models. A conclusion is drawn of the collective interaction mechanism (perhaps, of the shock wave type) of particle ejection from the target nucleus at the first stage of interaction and of explosive decay of the residual nucleus at the next one

  15. Nuclear spectroscopy of exotic nuclei with the SARA/IGISOL facility

    International Nuclear Information System (INIS)

    Beraud, R.; Emsallem, A.; Astier, A.; Duffait, R.; Aerje, J.; Aeystoe, J.; Jauho, P.; Barneoud, D.; Genevey, J.; Gizon, A.

    1995-01-01

    Some recent decay studies of neutron-rich and proton-rich nuclei are presented for nuclear structure investigations far off the valley of stability. The experiments, carried out at SARA, are based either on charged particle-induced fission of 238 U or on HI-induced fusion-evaporation reactions in combination with the IGISOL technique. The basic principle of this latter is recalled together with its advantages and limitations. The spectroscopic results obtained in three different regions of the chart of nuclei are sketched. (authors). 30 refs., 7 figs

  16. Reflection asymmetric shapes in nuclei

    International Nuclear Information System (INIS)

    Ahmad, I.; Carpenter, M.P.; Emling, H.

    1989-01-01

    Experimental data show that there is no even-even nucleus with a reflection asymmetric shape in its ground state. Maximum octupole- octupole correlations occur in nuclei in the mass 224 (N∼134, Z∼88) region. Parity doublets, which are the characteristic signature of octupole deformation, have been observed in several odd mass Ra, Ac and Pa nuclei. Intertwined negative and positive parity levels have been observed in several even-even Ra and Th nuclei above spin ∼8ℎ. In both cases, the opposite parity states are connected by fast El transitions. In some medium-mass nuclei intertwined negative and positive parity levels have also been observed above spin ∼7ℎ. The nuclei which exhibit octupole deformation in this mass region are 144 Ba, 146 Ba and 146 Ce; 142 Ba, 148 Ce, 150 Ce and 142 Xe do not show these characteristics. No case of parity doublet has been observed in the mass 144 region. 32 refs., 16 figs., 1 tab

  17. In vivo imaging of cell nuclei by photoacoustic microscopy without staining

    Science.gov (United States)

    Yao, Da-Kang; Chen, Ruimin; Maslov, Konstantin; Zhou, Qifa; Wang, Lihong V.

    2012-02-01

    Ultraviolet photoacoustic microscopy (UVPAM) can image cell nuclei in vivo with high contrast and resolution noninvasively without staining. Here, we used UV light at wavelengths of 210-310 nm for excitation of DNA and RNA to produce photoacoustic waves. We applied the UVPAM to in vivo imaging of cell nuclei in mouse skin, and obtained UVPAM images of the unstained cell nuclei at wavelengths of 245-282 nm as ultrasound gel was used for acoustic coupling. The largest ratio of contrast to noise was found for the images of cell nuclei at a 250 nm wavelength.

  18. Pion Rescattering in Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Paschos, E.A. [Institute for Physics, University of Dortmund, 44221 Dortmund (Germany); Schienbein, I. [Deutsches Elektronen Synchroton (DESY), 22603 Hamburg (Germany); Yu, J.-Y. [Institute for Physics, University of Dortmund, 44221 Dortmund (Germany)

    2005-02-15

    Nuclear corrections are presented for neutrino and electron induced reactions in a pedagogical manner. The formalism is demonstrated with numerical studies and shown to produce substantial corrections in channels where the pions have the same charge with the exchanged current. Two comparisons with available data show consistency of the model. Additional experimental results along these lines will improve the accuracy of the predictions and enhance the discovery potential of experiments.

  19. Spectroscopy of few-particle nuclei around magic 132Sn from fission product γ-ray studies

    International Nuclear Information System (INIS)

    Zhang, C. T.

    1998-01-01

    We are studying the yrast structure of very neutron-rich nuclei around doubly magic 132 Sn by analyzing fission product γ-ray data from a 248 Cm source at Eurogam II. Yrast cascades in several few-valence-particle nuclei have been identified through γγ cross coincidences with their complementary fission partners. Results for two-valence-particle nuclei 132 Sb, 134 Te, 134 Sb and 134 Sn provide empirical nucleon-nucleon interactions which, combined with single-particle energies already known in the one-particle nuclei, are essential for shell-model analysis in this region. Findings for the N = 82 nuclei 134 Te and 135 I have now been extended to the four-proton nucleus 136 Xe. Results for the two-neutron nucleus 134 Sn and the N = 83 isotones 134 Sb, 135 Te and 135 I open up the spectroscopy of nuclei in the northeast quadrant above 132 Sn

  20. Protonic decay of oriented nuclei

    International Nuclear Information System (INIS)

    Kadmensky, S.G.

    2002-01-01

    On the basis of the multiparticle theory of protonic decay, the angular distributions of protons emitted by oriented spherical and deformed nuclei in the laboratory frame and in the internal coordinate frame of deformed parent nuclei are constructed with allowance for symmetry with respect to time inversion. It is shown that, because of the deep-subbarrier character of protonic decay, the adiabatic approximation is not applicable to describing the angular distributions of protons emitted by oriented deformed nuclei and that the angular distribution of protons in the laboratory frame does not coincide with that in the internal coordinate frame. It is demonstrated that these angular distributions coincide only if the adiabatic and the semiclassical approximation are simultaneously valid

  1. Seleção de fungos produtores de tanase em resíduos vegetais ricos em taninos Screening of tanase producing fungi present in rich tannin vegetable residues

    Directory of Open Access Journals (Sweden)

    Gabriela Alves Macedo

    2005-08-01

    advantages over submerged and liquid conventional fermentation for the enzimes production. The production is simple, using vegetable residues such as coffee wastes, grape, cashew or by-products as wheat bran, rice or oats, to which tannic acid is added. The use of residues is an alternative to solve pollution problems that can be caused by an incorrect environmental disposal. Tannase enzyme has several applications on food, juices and pharmaceutical industries. The objective of this work was to select tannase producing fungi and to study the production of this enzyme in vegetable residues rich in tannin. The first stage of the selection was carried in solid-state fermentation using as substrate wheat bran supplemented with 0.5% of tannic acid. Among the 400 tested lineages, 6.75% of the fungi produced the enzyme. The lineages that showed the best activities were LAB345G, LAB53G and LAB153G, with 0.3862, 0.2149 and 0.1848 U activities values, respectively these lineages were tested in vegetables residues as coffee and grape, adding 0.5 and 1.5% of tannic acid in the fermentation environment. The best result was obtained using LA153G and coffee residues, with an activity of 0.275U being observed.

  2. Structure and symmetries of odd-odd triaxial nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Palit, R. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Colaba, Mumbai (India); Bhat, G.H. [University of Kashmir, Department of Physics, Srinagar (India); Govt. Degree College Kulgam, Department of Physics, Kulgam (India); Sheikh, J.A. [University of Kashmir, Department of Physics, Srinagar (India); Cluster University of Srinagar, Srinagar, Jammu and Kashmir (India)

    2017-05-15

    Rotational spectra of odd-odd Rh and Ag isotopes are investigated with the primary motivation to search for the spontaneous chiral symmetry breaking phenomenon in these nuclei. The experimental results obtained on the degenerate dipole bands of some of these isotopes using a large array of gamma detectors are discussed and studied using the triaxial projected shell (TPSM) approach. It is shown that, first of all, to reproduce the odd-even staggering of the known yrast bands of these nuclei, large triaxial deformation is needed. This large triaxial deformation also gives rise to doublet band structures in many of these studied nuclei. The observed doublet bands in these isotopes are shown to be reproduced reasonably well by the TPSM calculations. Further, the TPSM calculations for neutron-rich nuclei indicate that the ideal manifestation of the chirality can be realised in {sup 106}Rh and {sup 112}Ag, where the doublet bands have similar electromagnetic properties along with small differences in excitation energies. (orig.)

  3. Neutron scattering on deformed nuclei

    International Nuclear Information System (INIS)

    Hansen, L.F.; Haight, R.C.; Pohl, B.A.; Wong, C.; Lagrange, C.

    1984-09-01

    Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9 Be, C, 181 Ta, 232 Th, 238 U and 239 Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP

  4. Nuclei, hadrons, and elementary particles

    International Nuclear Information System (INIS)

    Bopp, F.W.

    1989-01-01

    This book is a short introduction to the physics of the nuclei, hadrons, and elementary particles for students of physics. Important facts and model imaginations on the structure, the decay, and the scattering of nuclei, the 'zoology' of the hadrons and basic facts of hadronic scattering processes, a short introduction to quantum electrodynamics and quantum chromodynamics and the most important processes of lepton and parton physics, as well as the current-current approach of weak interactions and the Glashow-Weinberg-Salam theory are presented. (orig.) With 153 figs., 10 tabs [de

  5. Octupole shapes in heavy nuclei

    International Nuclear Information System (INIS)

    Ahmad, I.

    1994-01-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets

  6. Spinodal decomposition of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, P. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Colonna, M.; Guarnera, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)]|[LNS, Catania (Italy)

    1996-12-31

    Multifragmentation of atomic nuclei is discussed. It is shown that this description of the dynamics of first order phase transitions in infinite and finite system is now partially achieved. An important conclusion is that in some specific cases well-defined collective motions were initiating the self-organisation of the unstable matter in fragments. In the case of finite systems the possible signals kept from this early fragmentation stage can inform on the possible occurrence of a liquid-gas phase transition in nuclei. (K.A.). 21 refs.

  7. Spinodal decomposition of atomic nuclei

    International Nuclear Information System (INIS)

    Chomaz, P.; Colonna, M.; Guarnera, A.

    1996-01-01

    Multifragmentation of atomic nuclei is discussed. It is shown that this description of the dynamics of first order phase transitions in infinite and finite system is now partially achieved. An important conclusion is that in some specific cases well-defined collective motions were initiating the self-organisation of the unstable matter in fragments. In the case of finite systems the possible signals kept from this early fragmentation stage can inform on the possible occurrence of a liquid-gas phase transition in nuclei. (K.A.)

  8. Are there superheavy atomic nuclei

    International Nuclear Information System (INIS)

    Herrmann, G.

    1982-04-01

    The author presents a populary introduction to the formation of nuclei with special regards to superheavy nuclei. After a general description of the methods of physics the atomic hypothesis is considered. Thereafter the structure of the nucleus is discussed, and the different isotopes are considered. Then radioactivity is described as an element transmutation. Thereafter the thermonuclear reactions in the sun are considered. Then the synthesis of elements using heavy ion reactions is described. In this connection the transuranium elements and the superheavy elements are considered. (orig./HSI) [de

  9. The mechanism of total disintegration of heavy nuclei by fast hadrons and nuclei

    International Nuclear Information System (INIS)

    Strugalska-Gola, E.; Strugalski, Z.

    1997-01-01

    The mechanism of the total disintegration of atomic nuclei by fast hadrons and nuclei is considered. The passage of energetic hadrons through layers of intranuclear matter, accompanied by emission of fast nucleons with kinetic energies from about 20 up to about 500 MeV from definite local small regions in the nuclei around projectile courses in them, allows one to explain simply the occurrence of the total destruction of nuclei involved in the collisions. Light nuclei may be totally disintegrated by fast hadrons and nuclei; heavier nuclei may be totally disintegrated only in central collisions of nuclei with similar mass numbers

  10. Increased ionization supports growth of aerosols into cloud condensation nuclei

    DEFF Research Database (Denmark)

    Svensmark, H.; Enghoff, M. B.; Shaviv, N. J.

    2017-01-01

    Ions produced by cosmic rays have been thought to influence aerosols and clouds. In this study, the effect of ionization on the growth of aerosols into cloud condensation nuclei is investigated theoretically and experimentally. We show that the mass-flux of small ions can constitute an important...... and find good agreement with theory. Ion-induced condensation should be of importance not just in Earth’s present day atmosphere for the growth of aerosols into cloud condensation nuclei under pristine marine conditions, but also under elevated atmospheric ionization caused by increased supernova activity....

  11. Galaxy mergers and active nuclei. II. Cosmological evolution

    International Nuclear Information System (INIS)

    Roos, N.

    1985-01-01

    Galaxy mergers may produce active galactic nuclei (AGNs) by repopulating stellar loss-cone orbits around a central black hole. In the companion paper we derived a local bolometric luminosity function of AGNs based on this process. In this paper we interpret the observed cosmological evolution of the luminosity function of AGNs as due to evolution of the merging rate among galaxies after their formation at a redshift of approx.3. An important difference between our model and previous (empirical) models is that the evolution depends on galactic (stellar) luminosity instead of central nonthermal luminosity. The radio counts at 1.4 GHz and optical counts are reproduced by the model if the merging rate of the galaxies at the bright end of the galaxy luminosity function evolves considerably faster than the merging rate of the smaller galaxies. The theoretical and observed luminosity functions at high redshift have similar characteristics: (i) at high luminosity the evolution is best described by luminosity evolution, and (2) the luminosity function has a maximum at approx.10 3 Gpc -3 , which is the space density of the most massive galaxies. A large fraction of these galaxies are presumably formed in the precursors of rich clusters. Their merger rate is high initially and declines rapidly on a time scale of a few billion years. If the initial density fluctuation spectrum for protoclusters of mass M/sub cl/ has the form deltarho/rhoproportionalM/sup( -1+n//3)/2/sub cl/, then the steep evolution of the most luminous galaxies suggests nroughly-equal-1.3 at a redshift of approx.3, which is consistent with the observed clustering of galaxies

  12. Nuclear isomerism in fission fragments produced by the spontaneous fission of {sup 252}Cf; Isomerisme nucleaire dans les fragments de fission produits dans la fission spontanee du {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C

    1997-09-01

    This thesis is devoted to the study of the nuclear structure of neutron-rich nuclei, via the search of isomeric nuclear states. Neutron-rich nuclei were produced in the spontaneous fission of {sup 252}Cf. The experimental study of isomeric states in these nuclei was performed with the {gamma}-array EUROGAM II, coupled to an additional and original fission fragment detector composed by photovoltaic cells, SAPhIR. The photovoltaic cells are well adapted to detect low energy heavy ions and have good energy and time resolutions to obtain a good fission fragment detection. This experiment led to the discovery of new isomeric states in {sup 135}Xe, {sup 104}Mo, {sup 146,147,148}Ce and {sup 152,154,156}Nd, with lifetimes between 60 ns and 2 {mu}s. Level schemes of these nuclei have been completed. An interpretation of the isomeric states in the nuclei {sup 154,156}Nd and {sup 156,158}Sm was performed by Hartree-Fock-Bogolyubov calculations using the DIS Gogny force with two quasi-particles excitations. The confrontation with the experimental results led to an interpretation of these isomeric states as K-isomers. (author)

  13. Transitional nuclei near shell closures

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064, India and Present Address: Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

    2014-08-14

    High spin states in Bismuth and Thallium nuclei near the Z = 82 shell closure and Cesium nuclei near the N = 82 shell closure in A = 190 and A = 130 regions, respectively, have been experimentally investigated using heavy-ion fusion evaporation reaction and by detecting the gamma rays using the Indian National Gamma Array (INGA). Interesting shape properties in these transitional nuclei have been observed. The results were compared with the neighboring nuclei in these two regions. The total Routhian surface (TRS) calculations have been performed for a better understanding of the observed properties. In mass region A = 190, a change in shape from spherical to deformed has been observd around neutron number N = 112 for the Bi (Z = 83) isotopes with proton number above the magic gap Z = 82, whereas, the shape of Tl (Z = 81) isotopes with proton number below the magic gap Z = 82 remains stable as a function of neutron number. An important transition from aplanar to planar configuration of angular momentum vectors leading to the occurance of nuclar chirality and magnetic rotation, respectively, has been proposed for the unique parity πh{sub 11/2}⊗νh{sub 11/2} configuration in Cs isotopes in the mass region A ∼ 130 around neutron number N = 79. These results are in commensurate with the TRS calculations.

  14. Cluster structure in Cf nuclei

    International Nuclear Information System (INIS)

    Singh, Shailesh K.; Biswal, S.K.; Bhuyan, M.; Patra, S.K.; Gupta, R.K.

    2014-01-01

    Due to the availability of advance experimental facilities, it is possible to probe the nuclei upto their nucleon level very precisely and analyzed the internal structure which will help us to resolve some mysterious problem of the decay of nuclei. Recently, the relativistic nuclear collision, confirmed the α cluster type structure in the 12 C which is the mile stone for the cluster structure in nuclei. The clustering phenomena in light and intermediate elements in nuclear chart is very interesting. There is a lot of work done by our group in the clustering behaviour of the nuclei. In this paper, the various prospectus of clustering in the isotopes of Cf nucleus including fission state is discussed. Here, 242 Cf isotope for the analysis, which is experimentally known is taken. The relativistic mean field model with well established NL3 parameter set is taken. For getting the exact ground state configuration of the isotopes, the calculation for minimizing the potential energy surface is performed by constraint method. The clustering structure of other Cf isotopes is discussed

  15. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  16. Particle detection from oriented nuclei

    International Nuclear Information System (INIS)

    Wouters, J.; Moor, P. de; Schuurmans, P.; Severijns, N.; Vanderpoorten, W.; Vanneste, L.

    1992-01-01

    A survey is given of particle emission from nuclei that have been spin oriented by cryogenical means. Experiments and recent developments with detectors in the low temperature environment and their on-line application are reviewed. The most recent results are mentioned. Some phenomena to be unraveled in future studies are pointed out. (orig.)

  17. Rotational damping motion in nuclei

    International Nuclear Information System (INIS)

    Egido, J.L.; Faessler, A.

    1991-01-01

    The recently proposed model to explain the mechanism of the rotational motion damping in nuclei is exactly solved. When compared with the earlier approximative solution, we find significative differences in the low excitation energy limit (i.e. Γ μ 0 ). For the strength functions we find distributions going from the Wigner semicircle through gaussians to Breit-Wigner shapes. (orig.)

  18. Percolation and multifragmentation of nuclei

    International Nuclear Information System (INIS)

    Shmakov, S.Yu.; Uzhinskij, V.V.

    1989-01-01

    A method to build the 'cold' nuclei as percolation clusters is suggested. Within the framework of definite assumptions of the character of nucleon-nucleon couplings breaking resulting from the nuclear reactions as description of the multifragmentation process in the hadron-nucleus and nucleus-nucleus reactions at high energies is obtained. 19 refs.; 6 figs

  19. Octupole correlation effects in nuclei

    International Nuclear Information System (INIS)

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions

  20. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world's first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density ...

  1. Production of spin-polarized unstable nuclei by using polarized electron capture process

    International Nuclear Information System (INIS)

    Shimizu, S.

    1998-01-01

    Measurements of emitted radiation from spin polarized nuclei are used to get information on electromagnetic moment of ground state unstable nuclei together with spin or parity state of excited states of their decayed (daughter) nuclei. These data are known to be useful for experimental investigation into the structure of unstable nuclei far from the stability line. The present study aims to establish a general method applicable to 11 Be and 16 N nuclei. To produce spin polarization, a new method in which the electron spin polarization of Rb is firstly produced by laser pumping, then the electron is transferred to the unstable nuclear beam (RNB) when they passes through the Rb vapor is proposed. Finally the polarized RNB will be implanted into superfluid helium to remain with a long spin-relaxation time. Future experimental set up for the above measurement adopted in the available radioactive nuclear beam facilities is briefly described. (Ohno, S.)

  2. Probing the Evolution of the Shell Structures in Exotic Nuclei

    International Nuclear Information System (INIS)

    De Angelis, Giacomo

    2008-01-01

    Magic numbers are a key feature in finite Fermion systems since they are strongly related to the underlying mean field. The size of the shell gaps and their evolution far from stability can be linked to the shape and symmetry of the nuclear mean field. Moreover the study of nuclei with large neutron/proton ratio allow to probe the density dependence of the effective interaction. Changes of the nuclear density and size in nuclei with increasing N/Z ratios are expected to lead to different nuclear symmetries and excitations. In this contribution I will discuss some selected examples which show the big potential of stable beams and of binary reactions for the study of the properties of the neutron-rich nuclear many body systems.

  3. Microscopical description of isovector collective Osup(+) states in atomic nuclei

    International Nuclear Information System (INIS)

    Chekanov, N.A.

    1983-01-01

    A microscopical consistent description of isobar-analogue states and isovector monopole giant resonances is given in framework of the random-phase theory. The necessary one-particle basis, including the continuous spectrum, is determined by solution of the Hartree-Fock equations with the effective Skyrme-type interaction. An important feature of such a description is an automatical fulfilment of the consistency conditions relating the shell potential, nuclear density and the residual interaction. Effects due to Coulomb interaction in nuclei are investigated, such as the Coulomb shift energies, isospin admixtures to the ground state of the parent nucleus. Transition densities for the analogue states are obtained. Numerical calculations have been performed in the coordinate space for a number of neutron-rich nuclei

  4. Decay properties of nuclei in the neighbourhood of 100Sn

    International Nuclear Information System (INIS)

    Straub, Katrin

    2011-01-01

    This thesis concentrates on nuclear properties of very neutron deficient nuclei near the proton dripline in the neighbourhood of doubly-magic 100 Sn. In an experiment performed in March 2008 at the GSI in Darmstadt, the exotic nuclei were produced in a projectile fragmentation reaction using a 124 Xe primary beam with an energy of 100 AMeV impinging on a 4000 Beryllium target, separated and identified in the FRS and eventually stopped for decay spectroscopy in a complex implantation detector developed at the institute E12. The Germanium array RISING was employed for the measurement of prompt and delayed gamma radiation. Production cross sections and half lives were determined along the proton dripline. The isotopes 99 Sn, 97 In and 95 Cd were identified for the first time. additional nuclei studied in this thesis are 103 Sn, 96 Cd as well as the two tin isotopes 101 Sn and 102 Sn. (orig.)

  5. Aspects of data on the breakup of highly excited nuclei

    International Nuclear Information System (INIS)

    Warwick, A.I.; Wieman, H.H.; Gutbrod, H.H.; Ritter, H.G.; Stelzer, H.; Weik, F.; Kaufman, S.B.; Steinberg, E.P.; Wilkins, B.D.

    1983-05-01

    There is an awakening of theoretical interest in the mechanisms by which nuclear fragments (4 less than or equal to A less than or equal to 150) are produced in violent collisions of heavy ions. With this in mind we review some aspects of the available experimental data and point out some challenging features against which to test the models. The concept of evaporation is tremendously powerful when applied to pieces of nuclei of low excitation (1 or 2 MeV/u). Current interest focuses on higher excitations, at the point where the binding energy of the system vanishes. This is the transition from liquid nuclei to a gas of nucleons, and it may be that the critical phenomena that certainly exist in infinite nuclear matter will be manifest in finite nuclei under these conditions

  6. Investigation of the core-halo structure of the neutron-rich nuclei {sup 6}He and {sup 8}He by intermediate-energy elastic proton scattering at high momentum transfer; Etude de la structure coeur-halo des noyaux riches en neutron {sup 6}He et {sup 8}He par la diffusion elastique de protons aux energies intermediaires etendue a la region du premier minimum de diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Aksouh, F

    2002-12-01

    The elastic proton scattering from the halo nuclei {sup 6}He and {sup 8}He was investigated in inverse kinematics at energies around 700 MeV/u with the aim to deduce the differential cross sections for the region of high momentum transfer, covering the first diffraction minimum. For this purpose, a liquid-hydrogen target was specially developed and used for the first time allowing to obtain low-background data as compared to commonly used targets made from C-H compounds. Previous data taken in the region of small momentum transfer were sensitive to the size and the peripheral shape of the total nuclear matter density distribution but not to the inner part. The present data allow for a more detailed insight in the structure of the alike core in {sup 6,8}He through a better determination of the matter density distributions. Several density distributions calculated from different microscopic models were used to derive elastic scattering cross sections which are compared with the obtained data. (author)

  7. Present and Future Experiments with Stored Exotic Nuclei at GSI

    International Nuclear Information System (INIS)

    Geissel, H.

    2009-01-01

    Recent results and perspectives of experiments with stored exotic nuclei at GSI-FAIR will presented. An overview on the planned NUSTAR experiments will also presented. Relativistic exotic nuclei produced via projectile fragmentation and fission were separated in flight by the fragment separator FRS and injected into the storage-cooler ring ESR for accurate mass- and lifetime measurements. Direct mass measurements of electron-cooled exotic nuclei were performed using time-resolved Schottky spectrometry. Fragments with half-lives shorter than the time required for electron cooling have been investigated by time-of-flight measurements with the ESR being operated in the isochronous mode. This novel experimental technique gives access to all nuclei with half-lives down to the microsecond range and has been successfully applied. Lifetimes of stored bare and few-electron ions have been measured with the goal to study the beta-decay under ionization conditions prevailing in stellar plasma. For the first time the direct observation of bound-state beta decay has been achieved with 2 07T l fragments. The future project FAIR includes a new large-acceptance in-flight separator (Super-FRS) in combination with a new storage ring system (CR, NESR) which will be ideal tools to study exotic nuclei far from stability.(author)

  8. RECOILING MASSIVE BLACK HOLES IN GAS-RICH GALAXY MERGERS

    International Nuclear Information System (INIS)

    Guedes, Javiera; Madau, Piero; Mayer, Lucio; Callegari, Simone

    2011-01-01

    The asymmetric emission of gravitational waves produced during the coalescence of a massive black hole (MBH) binary imparts a velocity 'kick' to the system that can displace the hole from the center of its host. Here, we study the trajectories and observability of MBHs recoiling in three (one major, two minor) gas-rich galaxy merger remnants that were previously simulated at high resolution, and in which the pairing of the MBHs had been shown to be successful. We run new simulations of MBHs recoiling in the major merger remnant with Mach numbers in the range 1≤M≤6 and use simulation data to construct a semi-analytical model for the orbital evolution of MBHs in gas-rich systems. We show the following. (1) In major merger remnants the energy deposited by the moving hole into the rotationally supported, turbulent medium makes a negligible contribution to the thermodynamics of the gas. This contribution becomes significant in minor merger remnants, potentially allowing for an electromagnetic signature of MBH recoil. (2) In major merger remnants, the combination of both deeper central potential well and drag from high-density gas confines even MBHs with kick velocities as high as 1200 km s -1 within 1 kpc from the host's center. (3) Kinematically offset nuclei may be observable for timescales of a few Myr in major merger remnants in the case of recoil velocities in the range 700-1000 km s -1 . (4) In minor merger remnants the effect of gas drag is weaker, and MBHs with recoil speeds in the range 300-600 km s -1 will wander through the host halo for longer timescales. When accounting for the probability distribution of kick velocities, however, we find that the likelihood of observing recoiling MBHs in gas-rich galaxy mergers is very low even in the best-case scenario.

  9. Bands and chromosome arrangement in interphase nuclei

    International Nuclear Information System (INIS)

    Bianchi, N.O.; Bianchi, M.A.; Matayoshi, T.

    1977-01-01

    Chromosomes from the vole mouse Akodon dolores and from laboratory mouse showed the presence of G-bands after 3 minutes digestion with trypsin and Giemsa stain. Simultaneously, 30- to 40% of the interphase nuclei exhibited a dark ring parallel to the nuclear contour and a radial array of the chromatin in the internal and external regions of the ring. The origin and meaning of this ring image was analyzed by combining progressive trypsinizations with other methods such as C-banding procedures, autoradiography with 3 HTdR, staining with quinacrine mustard and 33258 Hoechst fluorochromes. Moreover, the presence of the dark ring was also investigated in cells treated with actinomycin and in control cells not subjected to any treatment. The results obtained allowed to assume that in interphase nuclei the chromosomes have chromatin bridges which connect the dark G-bands and that these bridges are probably involved in maintaining an ordered architecture of the nucleus with fixed chromosome positions in regard to the nuclear envelope and in regard to other chromosomes. Trypsinization produces a disruption of the interphase chromatin arrangement and the subsequent appearance of a dark ring formed by the combination of constitutive heterochromatin and dark G-bands. (auth.)

  10. STELLAR TRANSITS IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Béky, Bence; Kocsis, Bence

    2013-01-01

    Supermassive black holes (SMBHs) are typically surrounded by a dense stellar population in galactic nuclei. Stars crossing the line of site in active galactic nuclei (AGNs) produce a characteristic transit light curve, just like extrasolar planets do when they transit their host star. We examine the possibility of finding such AGN transits in deep optical, UV, and X-ray surveys. We calculate transit light curves using the Novikov-Thorne thin accretion disk model, including general relativistic effects. Based on the expected properties of stellar cusps, we find that around 10 6 solar mass SMBHs, transits of red giants are most common for stars on close orbits with transit durations of a few weeks and orbital periods of a few years. We find that detecting AGN transits requires repeated observations of thousands of low-mass AGNs to 1% photometric accuracy in optical, or ∼10% in UV bands or soft X-ray. It may be possible to identify stellar transits in the Pan-STARRS and LSST optical and the eROSITA X-ray surveys. Such observations could be used to constrain black hole mass, spin, inclination, and accretion rate. Transit rates and durations could give valuable information on the circumnuclear stellar clusters as well. Transit light curves could be used to image accretion disks with unprecedented resolution, allowing us to resolve the SMBH silhouette in distant AGNs.

  11. Precision measurement of the mass difference between light nuclei and anti-nuclei with ALICE at the LHC

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    is produced in the central pseudorapidity region allowing for a precise investigation of their properties. Mass and binding energy are expected to be the same in nuclei and anti-nuclei as long as the CPT invariance holds for the nuclear force, a remnant of the underlying strong interaction between quarks and gluons. The measurements of the difference in mass-to-charge ratio between deuteron and anti-deuteron, and 3He and 3\\bar{He} nuclei performed with the ALICE detector at the LHC is presented. The ALICE measurements improve by one to two orders of magnitude previous analogous direct measurements. Given the equivalence between mass and energy, the results improve by a factor two the constraints on CPT invariance inferred from measurements in the (anti-)deuteron system. The binding energy difference has been determined for the first time in the case of (anti-)3He, with a precision comparable to the one obtained in the...

  12. Role of compound nuclei in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-05-01

    Hot compound nuclei are frequently produced in intermediate-energy reactions through a variety of processes. Their decay is shown to be an important and at times dominant source of complex fragments, high energy-gamma rays, and even pions

  13. Compound nuclei, binary decay, and multifragmentation in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-07-01

    Hot compound nuclei, frequently produced in intermediate-energy reactions through a variety of processes, are shown to be an important and at times dominant source of complex fragments. 13 refs., 12 figs

  14. Isospin-symmetry-breaking effects in A∼70 nuclei within beyond-mean-field approach

    Energy Technology Data Exchange (ETDEWEB)

    Petrovici, A.; Andrei, O. [National Institute for Physics and Nuclear Engineering, R-077125 Bucharest (Romania)

    2015-02-24

    Particular isospin-symmetry-breaking probes including Coulomb energy differences (CED), mirror energy differences (MED), and triplet energy differences (TED) manifest anomalies in the A∼70 isovector triplets of nuclei. The structure of proton-rich nuclei in the A∼70 mass region suggests shape coexistence and competition between pairing correlations in different channels. Recent results concerning the interplay between isospin-mixing and shape-coexistence effects on exotic phenomena in A∼70 nuclei obtained within the beyond-mean-field complex Excited Vampir variational model with symmetry projection before variation using a realistic effective interaction in a relatively large model space are presented. Excited Vampir predictions concerning the Gamow-Teller β decay to the odd-odd N=Z {sup 66}As and {sup 70}Br nuclei correlated with the pair structure analysis in the T=1 and T=0 channel of the involved wave functions are discussed.

  15. Studies of the neutron single-particle structure of exotic nuclei at the HRIBF

    International Nuclear Information System (INIS)

    Thomas, J.S.; Bardayan, D.W.; Blackmon, J.C.; Cizewski, J.A.; Greife, U.; Gross, C.J.; Johnson, M.S.; Jones, K.L.; Kozub, R.L.; Liang, J.F.; Livesay, R.J.; Ma, Z.; Moazen, B.H.; Nesaraja, C.D.; Shapira, D.; Smith, M.S.

    2004-01-01

    The study of neutron single-particle strengths in neutron-rich nuclei is of interest for nuclear structure and nuclear astrophysics. The distribution of single-particle strengths constrains the effective Hamiltonian and pairing interactions and determines neutron interaction rates that are crucial for understanding the synthesis of heavy nuclei in supernovae via the rapid neutron capture process. Particularly important are the neutron single-particle levels in nuclei near closed neutron shells. Radioactive ion beams from the Holifield Radioactive Ion Beam Facility have been used to study (d,p) reactions in inverse kinematics in order to probe neutron single-particle states in exotic nuclei. The results of a measurement with a 82 Ge beam will be presented

  16. Radioactive ion beams - A tool to study structure of nuclei far from stability

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Zdeněk

    2006-01-01

    Roč. 56, č. 2 (2006), s. 91-94 ISSN 0323-0465 R&D Projects: GA ČR GA202/04/0791 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutron-rich nuclei * elactic-scattering * N=20 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.647, year: 2006

  17. Fingerprint states of odd mass 115I nuclei in the framework of particle rotor model

    International Nuclear Information System (INIS)

    Goswami, R.; Saha Sarkar, M.; Sen, S.

    2008-01-01

    Extensive theoretical as well as experimental investigation of the nuclear structure of odd-mass iodine nuclei have revealed systematic presence of strongly coupled bands in all neutron deficient as well as neutron rich odd-mass iodine isotopes. The present work shows that the positive as well as the negative parity are fairly well reproduced in the framework of particle rotor model

  18. Beta decay of polarized nuclei and the decay asymmetry of 8Li

    International Nuclear Information System (INIS)

    Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.

    1985-01-01

    Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li

  19. Cavitation nuclei measurements - A review

    International Nuclear Information System (INIS)

    Billet, M.L.

    1985-01-01

    The measurement of cavitation nuclei has been the goal of many cavitation research laboratories and has resulted in the development of many methods. Two significantly different approaches have been developed. One is to measure the particulate-microbubble distribution by utilizing acoustical, electrical or optical methods. The other approach measures a liquid tension and a rate of cavitation events for a liquid in order to establish a cavitation susceptibility. Comparisons between various methods indicate that most methods are capable of giving an indication of the nuclei distribution. Measurements obtained in the ocean environment indicate an average of three bubbles per cubic centimeter are present; whereas, water tunnel bubble distributions vary from much less than one to over a hundred per cubic centimeter

  20. Phonon operators in deformed nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1981-01-01

    For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator [ru

  1. Phonon operators for deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1982-01-01

    The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator

  2. Nuclear treasure island [superheavy nuclei

    CERN Document Server

    CERN. Geneva

    1999-01-01

    Summary form only given. Soon after the experiments at Dubna, which synthesized element 114 and made the first footprints on the beach of the "island of nuclear stability", two new superheavy elements have been discovered at the Lawrence Berkeley National Laboratory. Element 118 and its immediate decay product, element 116, were manufactured at Berkeley's 88 inch cyclotron by fusing targets of lead-208 with an intense beam of 449 MeV krypton-86 ions. Although both new nuclei almost instantly decay into lighter ones, the decay sequence is consistent with theories that have long predicted the island of stability for nuclei with approximately 114 protons and 184 neutrons. Theorist Robert Smolanczuk, visiting from the Soltan Institute for Nuclear Studies in Poland, had calculated that this reaction should have particularly favourable production rates. Now that this route has been signposted, similar reactions could be possible: new elements and isotopes, tests of nuclear stability and mass models, and a new under...

  3. Moessbauer effects on oriented nuclei

    International Nuclear Information System (INIS)

    Sayouti, E.H.

    1984-01-01

    Standard nuclear orientation methods (not sensitive to the polarization) do not give information on the sign of the magnetic moment. Mossbauer effect separates right-hand and left-hand circularly polarized components, thus its detection on oriented nuclei (T approximately 10 mK) gives the sign of the magnetic moment of oriented state. In this thesis we applied this method to study the 3/2 - ground states of 191 Pt and 193 Os, which are in the prolate-oblate transition region, where assignement of experimental levels to theoretical states is often umbiguous. We show that for those nuclei the sign of the magnetic moment is the signature of the configuration, and its determination establishes the correspondance between experimental and theoretical levels [fr

  4. Isomer spectroscopy of neutron-rich 168 Tb 103

    Energy Technology Data Exchange (ETDEWEB)

    Gurgi, L. A.; Regan, P. H.; Söderström, P. -A.; Watanabe, H.; Walker, P. M.; Podolyák, Zs.; Nishimura, S.; Berry, T. A.; Doornenbal, P.; Lorusso, G.; Isobe, T.; Baba, H.; Xu, Z. Y.; Sakurai, H.; Sumikama, T.; Catford, W. N.; Bruce, A. M.; Browne, F.; Lane, G. J.; Kondev, F. G.; Odahara, A.; Wu, J.; Liu, H. L.; Xu, F. R.; Korkulu, Z.; Lee, P.; Liu, J. J.; Phong, V. H.; Yag, A.; Zhang, G. X.; Alharbi, T.; Carroll, R. J.; Chae, K. Y.; Dombradi, Zs.; Estrade, A.; Fukuda, N.; Griffin, C.; Ideguchi, E.; Inabe, N.; Kanaoka, H.; Kojouharov, I.; Kubo, T.; Kubono, S.; Kurz, N.; Kuti, I.; Lalkovski, S.; Lee, E. J.; Lee, C. S.; Lotay, G.; Moon, C. -B.; Nishizuka, I.; Nita, C. R.; Patel, Z.; Roberts, O. J.; Schaffner, H.; Shand, C. M.; Suzuki, H.; Takeda, H.; Terashima, S.; Vajta, Zs.; Yoshida, S.; Valiente-Dòbon, J. J.

    2017-11-01

    In-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm thick 9Be target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus 170Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified event-by-event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent β-decay. Discrete γ-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3) fast-timing scintillation detectors from the FATIMA collaboration. This paper presents the internal decay of a metastable isomeric excited state in the odd-odd nucleus 168Tb, which corresponds to a single proton-neutron hole configuration in the valence maximum nucleus 170Dy. These data represent the first information on excited states in this nucleus, which is the most neutron-rich odd-odd isotope of terbium (Z=65) studied to date. Nilsson configurations associated with an axially symmetric, prolate-deformed nucleus are proposed for the 168Tb ground state the observed isomeric state by comparison with Blocked BCS-Nilsson calculations.

  5. Mesons and quarks in nuclei

    International Nuclear Information System (INIS)

    Oset, E.

    1980-01-01

    A short review of the topic of mesons in nuclei is exposed paying particular attention to the relationship between several mesonic processes. Special emphasis is put into the microscopic pictures that can ultimately relate all these processes with the elementary coupling of mesons to the nuclear hadronic components. The importance of the short range part of the nuclear interaction opens the doors to a more basic understanding in terms of the quark components of nucleons and isobars. (orig.)

  6. Exclusive photoreactions on light nuclei

    International Nuclear Information System (INIS)

    Maruyama, K.

    1989-08-01

    The mechanism of photon absorption on light nuclei in the Δ-resonance region is discussed. The present status of experimental results is briefly summarized. A recent data from 1.3-GeV Tokyo ES using a π sr spectrometer is introduced. Exclusive measurements of the photodisintegration of 3 He and 4 He may be a clear way to identify 2N, 3N and 4N absorptions. (author)

  7. Fission barriers of light nuclei

    International Nuclear Information System (INIS)

    Grotowski, K.; Planeta, R.; Blann, M.; Komoto, T.

    1989-01-01

    Experimental fission excitation functions for compound nuclei /sup 52/Fe, /sup 49/Cr, /sup 46/V, and /sup 44/Ti formed in heavy-ion reactions are analyzed in the Hauser-Feshbach/Bohr-Wheeler formalism using fission barriers based on the rotating liquid drop model of Cohen et al. and on the rotating finite range model of Sierk. We conclude that the rotating finite range approach gives better reproduction of experimental fission yields, consistent with results found for heavier systems

  8. Production of polarized vector mesons off nuclei

    International Nuclear Information System (INIS)

    Kopeliovich, B. Z.; Nemchik, J.; Schmidt, Ivan

    2007-01-01

    Using the light-cone QCD dipole formalism we investigate manifestations of color transparency (CT) and coherence length (CL) effects in electroproduction of longitudinally (L) and transversally (T) polarized vector mesons. Motivated by forthcoming data from the HERMES experiment we predict both the A and Q 2 dependence of the L/T ratios for ρ 0 mesons produced coherently and incoherently off nuclei. For an incoherent reaction the CT and CL effects add up and result in a monotonic A dependence of the L/T ratio at different values of Q 2 . In contrast, for a coherent process the contraction of the CL with Q 2 causes an effect opposite to that of CT and we expect quite a nontrivial A dependence

  9. Exotic nuclei arena in Japanese Hadron Project

    International Nuclear Information System (INIS)

    Nomura, T.

    1990-04-01

    A description is given on the radioactive beam facility proposed as one of the research arenas in Japanese Hadron Project. The facility consists of a 1 GeV proton linac, an isotope separator on-line (ISOL) and a series of heavy-ion (HI) linacs. Various exotic nuclei produced by 1 GeV proton beam mainly via spallation processes of a thick target, are mass-separated by the ISOL with a high mass-resolving power and are injected into the HI linac with the energy of 1 keV/u. The acceleration is made in three stages using different types of linacs, i.e., split-coaxial RFQ. Interdigital-H, and Alvarez, the maximum energy in each stage being 0.17, 1.4 and 6.5 MeV/u, respectively. A few examples of scientific interests realized in this facility will be briefly discussed. (author)

  10. Isospin effects and hot nuclei

    International Nuclear Information System (INIS)

    Gagnon-Moisan, Francis

    2010-01-01

    The rapid decomposition (t≤10 -21 seconds) of a nucleus into multiple fragments, named multifragmentation, is associated to a liquid-gas phase transition. For many years, physicists have tried to obtain an experimental proof of this behaviour. It has been suggested that, to achieve this, one could observe the particular signature of the mechanism of such a transition: the spinodal decomposition, through the production of equal size fragments. A method is that of charge correlation using intrinsic probabilities. The 5. campaign for the INDRA multidetector which took place at GANIL was aimed at obtaining a high number of events, in order to sign the spinodal decomposition with a high confidence level. The chosen systems were 124 Xe+ 112 Sn and 136 Xe+ 124 Sn at beam energies of 32 and 45 AMeV. The acquired statistics allowed to confirm the existence of events with very narrow charge distributions, which agrees with the spinodal decomposition hypothesis. The study of 124 , 136 Xe+ 112 , 124 Sn at 32 and 45 AMeV shows the impact of neutron density on the exit channel: a neutron-rich system produces more fragments and fewer particles than a system initially neutron-poor. Finally, the modification on 27 modules from the INDRA multidetector allows the isotopic resolution of fragments up to oxygen (Z=8). This provides the information required for the study of the N/Z ratio of fragments versus their kinetic energy with the goal of obtaining an experimental constraint on the symmetry term of the equation of state. (author)

  11. Density functional theory of nuclei

    International Nuclear Information System (INIS)

    Terasaki, Jun

    2008-01-01

    The density functional theory of nuclei has come to draw attention of scientists in the field of nuclear structure because the theory is expected to provide reliable numerical data in wide range on the nuclear chart. This article is organized to present an overview of the theory to the people engaged in the theory of other fields as well as those people in the nuclear physics experiments. At first, the outline of the density functional theory widely used in the electronic systems (condensed matter, atoms, and molecules) was described starting from the Kohn-Sham equation derived on the variational principle. Then the theory used in the field of nuclear physics was presented. Hartree-Fock and Hartree-Fock-Bogolyubov approximation by using Skyrme interaction was explained. Comparison of the results of calculations and experiments of binding energies and ground state mean square charge radii of some magic number nuclei were shown. The similarity and dissimilarity between the two streams were summarized. Finally the activities of the international project of Universal Nuclear Energy Density Functional (UNEDF) which was started recently lead by US scientist was reported. This project is programmed for five years. One of the applications of the project is the calculation of the neutron capture cross section of nuclei on the r-process, which is absolutely necessary for the nucleosynthesis research. (S. Funahashi)

  12. Exotic Nuclei and Yukawa's Forces

    International Nuclear Information System (INIS)

    Otsuka, Takaharu; Suzuki, Toshio; Utsuno, Yutaka

    2008-01-01

    In this plenary talk, we will overview the evolution of the shell structure in stable and exotic nuclei as a new paradigm of nuclear structure physics. This shell evolution is primarily due to the tensor force. The robust mechanism and some examples will be presented. Such examples include the disappearance of existing magic numbers and the appearance of new ones. The nuclear magic numbers have been believed, since Mayer and Jensen, to be constants as 2, 8, 20, 28, 50, ... This turned out to be changed, once we entered the regime of exotic nuclei. This shell evolution develops at many places on the nuclear chart in various forms. For example, superheavy magic numbers may be altered. Thus, we are led to a new paradigm as to how and where the nuclear shell evolves, and what consequences arise. The evolution of the shell affects weak process transitions, and plays a crucial role in deformation. The π and ρ mesons generate tensor forces, and are the fundamental elements of such intriguing phenomena. Thus, physics of exotic nuclei arises as a manifestation of Yukawa's forces

  13. The colours of Hubble Sc galaxy nuclei

    International Nuclear Information System (INIS)

    Iskudaryan, S.G.

    1975-01-01

    The colorimetric data on the nuclei of the Sc galaxies are given. Comparison of the following parameters: color of a nucleus, integral color of a galaxy, Byurakan class, and spectral type of normal spirals gives the possibility to conclude: (1) The colors of the nuclei of the Sc galaxies have a high dispersion in its values. In all Byurakan classes the galaxies with intensely red and blue nuclei occur; (2) Some Sc galaxies exhibit a discrepancy between the spectral and morphological types. The results of colorimetry of nuclei indicate that almost all such Sc galaxies have intensely red nuclei which, naturally, provide for these late spectral types. It can be assumed that the intensely red color of the nuclei of such Sc galaxies is a result of a new type of activity of these nuclei; and (3) some Sc galaxies show the characteristics of the Markarian objects

  14. Efeito do número da passagem e do gênero das células doadoras de núcleo no desenvolvimento de bovinos produzidos por transferência nuclear Effect of culture time and gender of nuclei donor cells on bovine development produced by nuclear transfer

    Directory of Open Access Journals (Sweden)

    Giovana Krempel Fonseca Merighe

    2010-10-01

    blastocyst of embryo reconstructed with cells cultured for a longer time were lower than rates obtained with other culture times. Moreover, these produced blastocysts did not result in the development of full term pregnancy. Although cleavage rates were higher in female embryos, the number of embryos that reached blastocyst stage was higher in male embryos. During gestation period, females showed higher abortion rates from 90 to 120 days of gestation. These results indicate that cells donnors of nuclei cultured for long periods make the production of blastocysts difficult and increase the chances of losses during pregnancy. Cloned male embryos are more succesful in becoming blastocysts and result in lower gestational loss rate.

  15. Studies of Heavy-Ion Reactions and Transuranic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, W. Udo [Univ. of Rochester, NY (United States). Dept. of Chemistry. Dept. of Physics

    2016-07-28

    Studies of heavy-ion reactions and transuranic nuclei performed by the University of Rochester Nuclear Science Research Group have been successful in furthering experimental systematics and theoretical understanding of the behavior of nuclear systems excited to their limits of stability. The theoretical results explain specifically the “boiling” and “vaporization” of atomic nuclei, but are more generally applicable to isolated, quantal many-particle systems which, under thermal or mechanical stresses, all disintegrate by evaporation, via surface cluster emission, or via fission-like processes. Accompanying experimental investigations by the group have demonstrated several new types of dynamical instability of nuclei: In central, “head-on” collisions, target nuclei exhibit limited ability to stop energetic projectile nuclei and to dissipate the imparted linear momentum. Substantial matter overlap (“neck”) between projectile and target nuclei, which is observed at elevated collision energies, can be stretched considerably and break at several places simultaneously. These results provide new testing grounds for microscopic theory of the cohesion of nuclear matter. This property has remained elusive, even though the elementary nucleon-nucleon forces are well known since some time. Technical R&D has resulted in a detailed characterization of a novel plastic material, which can now be used in the design of sensitive diagnostic systems for various types of radio-activity. Innovative application of powerful laser systems has produced intense, controllable sources of exotic particle radioactivity for nuclear investigations. Several students have received their Ph.D. degree in experimental nuclear science for their work on basic nuclear research or R&D projects.

  16. Studies of Heavy-Ion Reactions and Transuranic Nuclei

    International Nuclear Information System (INIS)

    Schroeder, W. Udo

    2016-01-01

    Studies of heavy-ion reactions and transuranic nuclei performed by the University of Rochester Nuclear Science Research Group have been successful in furthering experimental systematics and theoretical understanding of the behavior of nuclear systems excited to their limits of stability. The theoretical results explain specifically the ''boiling'' and ''vaporization'' of atomic nuclei, but are more generally applicable to isolated, quantal many-particle systems which, under thermal or mechanical stresses, all disintegrate by evaporation, via surface cluster emission, or via fission-like processes. Accompanying experimental investigations by the group have demonstrated several new types of dynamical instability of nuclei: In central, ''head-on'' collisions, target nuclei exhibit limited ability to stop energetic projectile nuclei and to dissipate the imparted linear momentum. Substantial matter overlap (''neck'') between projectile and target nuclei, which is observed at elevated collision energies, can be stretched considerably and break at several places simultaneously. These results provide new testing grounds for microscopic theory of the cohesion of nuclear matter. This property has remained elusive, even though the elementary nucleon-nucleon forces are well known since some time. Technical R&D has resulted in a detailed characterization of a novel plastic material, which can now be used in the design of sensitive diagnostic systems for various types of radio-activity. Innovative application of powerful laser systems has produced intense, controllable sources of exotic particle radioactivity for nuclear investigations. Several students have received their Ph.D. degree in experimental nuclear science for their work on basic nuclear research or R&D projects.

  17. The CAPRICE RICH detector

    Energy Technology Data Exchange (ETDEWEB)

    Basini, G. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Codino, A.; Grimani, C. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); De Pascale, M.P. [Rome Univ. `Tor Vergata` (Italy). Dip. di Fisica]|[INFN, Sezione Univ. `Tor Vergata` Rome (Italy); Cafagna, F. [Bari Univ. (Italy)]|[INFN, Bari (Italy); Golden, R.L. [New Mexico State Univ., Las Cruces, NM (United States). Particle Astrophysics Lab.; Brancaccio, F.; Bocciolini, M. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Barbiellini, G.; Boezio, M. [Trieste Univ. (Italy)]|[INFN, Trieste (Italy)

    1995-09-01

    A compact RICH detector has been developed and used for particle identification in a balloon borne spectrometer to measure the flux of antimatter in the cosmic radiation. This is the first RICH detector ever used in space experiments that is capable of detecting unit charged particles, such as antiprotons. The RICH and all other detectors performed well during the 27 hours long flight.

  18. Determination of spin, magnetic moment and isotopic shift of neutron rich 205Hg by optical pumping

    International Nuclear Information System (INIS)

    Rodriguez, J.; Bonn, J.; Huber, G.; Kluge, H.J.; Otten, E.W.; European Organisation for Nuclear Research, Geneva

    1975-01-01

    Neutron rich 205 Hg(Tsub(1/2) = 5.2 min) was produced and on-line mass separated at the ISOLDE facility at CERN. The polarization achieved by optical pumping via the atomic line (6s 21 S 0 - 6s6p 3 P 1 , lambda = 2,537 A) was monitored by the β decay asymmetry. Hyperfine structure and isotopic shift of the 205 Hg absorption line was determined by Zeeman scanning. In addition a magnetic resoncance was performed on the polarized 205 Hg nuclei in the atomic ground state. The results are: I( 205 Hg) = 1/2 (confirmed); μ(I, 205 Hg) = 0.5915(1)μ(N) (uncorrected for diamagnetism); isotopic shift deltaν(204/205) = ν( 205 Hg) - ν( 204 Hg) = -1.8(1)GHz. μ(I) and IS are discussed briefly in the frame of current literature. (orig.) [de

  19. $\\beta$-decay study of neutron-rich Tl and Pb isotopes

    CERN Multimedia

    It is proposed to study the structure of neutron-rich nuclei beyond $^{208}$Pb. The one-proton hole $^{211-215}$Tl and the semi magic $^{213}$Pb will be produced and studied via nuclear and atomic spectroscopy searching for long-lived isomers and investigating the $\\beta$-delayed $\\gamma$- emission to build level schemes. Information on the single particle structure in $^{211-215}$Pb, especially the position of the g$_{9/2}$ and i$_{11/2}$ neutron orbitals, will be extracted along with lifetimes. The $\\beta$-decay will be complemented with the higher spin selectivity that can be obtained by resonant laser ionization to single-out the decay properties of long-living isomers in $^{211,213}$Tl and $^{213}$Pb.

  20. Recent shell-model results for exotic nuclei

    Directory of Open Access Journals (Sweden)

    Utsuno Yusuke

    2014-03-01

    Full Text Available We report on our recent advancement in the shell model and its applications to exotic nuclei, focusing on the shell evolution and large-scale calculations with the Monte Carlo shell model (MCSM. First, we test the validity of the monopole-based universal interaction (VMU as a shell-model interaction by performing large-scale shell-model calculations in two different mass regions using effective interactions which partly comprise VMU. Those calculations are successful and provide a deeper insight into the shell evolution beyond the single-particle model, in particular showing that the evolution of the spin-orbit splitting due to the tensor force plays a decisive role in the structure of the neutron-rich N ∼ 28 region and antimony isotopes. Next, we give a brief overview of recent developments in MCSM, and show that it is applicable to exotic nuclei that involve many valence orbits. As an example of its applications to exotic nuclei, shape coexistence in 32Mg is examined.