WorldWideScience

Sample records for neutron rich sodium

  1. Shape transition in the neutron rich sodium isotopes

    International Nuclear Information System (INIS)

    Campi, X.; Flocard, H.; Kerman, A.K.; Koonin, S.; Massachusetts Inst. of Tech., Cambridge

    1975-06-01

    Mass spectrometer measurements of the neutron rich sodium isotopes show a sudden increase at 31 Na in the values of the two neutron separation energies. The spherical shell model naturally predicts a sudden decrease at 32 Na after the N=20 shell closure. It is proposed that the explanation for this disagreement lies in the fact that sodium isotopes in this mass region are strongly deformed due to the filling of negative parity orbitals from the 1fsub(7/2) shell. Hartree-Fock calculations are presented in support of this conjecture [fr

  2. Investigation of the single Particle Structure of the neutron-rich Sodium Isotopes $^{27-31}\\!$Na

    CERN Document Server

    2002-01-01

    We propose to study the single particle structure of the neutron-rich isotopes $^{27-31}\\!$Na. These isotopes will be investigated via neutron pickup reactions in inverse kinematics on a deuterium and a beryllium target. Scattered beam particles and transfer products are detected in a position sensitive detector located around 0$^\\circ$. De-excitation $\\gamma$-rays emitted after an excited state has been populated will be registered by the MINIBALL Germanium array. The results will shed new light on the structure of the neutron-rich sodium isotopes and especially on the region of strong deformation around the N=20 nucleus $^{31}\\!$Na.

  3. Neutron und X-ray diffraction study on the superstructure of a sodium-rich low plagioclase An sub(16.5)

    International Nuclear Information System (INIS)

    Joswig, W.; Korekawa, M.

    1977-01-01

    Neutron and X-ray diffraction experiments had been carried out on a sodium-rich low plagioclase Ansub(16.5) from Sultan Hamud, Kenya. In constrast to previous work very weak (g) reflections (satellites) for all reflections Okl, except reflections 001, could be observed. It is shown that the neutron diffraction method is advantageous to study on submicroscopic periodic domain structure as reported here. (orig.) [de

  4. β Decay processes of neutron-rich isotopes of sodium and magnesium

    International Nuclear Information System (INIS)

    Guillemaud, D.

    1982-01-01

    The γ and n activities from the β decay of Na isotopes up to 34 Na, which are formed in high-energy fragmentation and analysed through mass-spectrometry techniques, are observed as well as those from their Mg descendants. Their intensities Isub(γ) and Isub(β) are measured; some radioactive half lives are determined. Delayed-neutron branching ratios Pn are measured. The existence of 35 Na is for the first time indicated. The position of the first excited 2 + level is taken as an indication of a stronger deformation for that isotope [fr

  5. 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

  6. Neutronic spectrometry measurements in sodium

    International Nuclear Information System (INIS)

    Perlini, G.; Acerbis, S.

    1987-01-01

    Measurements were made of neutronic penetration in sodium, which could serve as a reference and as a benchmark for computer codes. The model employed consisted of an assembly of 7 containers full of sodium for a total of 10 tons and a useful length of almost 4 metres. Measurements were performed at various depths along the central axis of the structure with proton recoil proportional counters. The energy band explored was between 100 and 650 keV. Here we report not only the original spectra of the impulses but also the neutronic spectra found by unfolding with the SPEC-4 code

  7. 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)

  8. 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

  9. Thermodynamics of neutron-rich nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    López, Jorge A., E-mail: jorgelopez@utep.edu [Department of Physics, University of Texas at El Paso, El Paso, Texas 79968, U.S.A (United States); Porras, Sergio Terrazas, E-mail: sterraza@uacj.mx; Gutiérrez, Araceli Rodríguez, E-mail: al104010@alumnos.uacj.mx [Universidad Autónoma de Ciudad Juárez, Ciudad Juárez, Chihuahua, México (Mexico)

    2016-07-07

    This manuscript presents methods to obtain properties of neutron-rich nuclear matter from classical molecular dynamics. Some of these are bulk properties of infinite nuclear matter, phase information, the Maxwell construction, spinodal lines and symmetry energy.

  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. Neutron rich matter, neutron stars, and their crusts

    International Nuclear Information System (INIS)

    Horowitz, C J

    2011-01-01

    Neutron rich matter is at the heart of many fundamental questions in Nuclear Physics and Astrophysics. What are the high density phases of QCD? Where did the chemical elements come from? What is the structure of many compact and energetic objects in the heavens, and what determines their electromagnetic, neutrino, and gravitational-wave radiations? Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that is using parity violation to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. Using large scale molecular dynamics, we model the formation of solids in both white dwarfs and neutron stars. We find neutron star crust to be the strongest material known, some 10 billion times stronger than steel. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. Finally, we describe a new equation of state for supernova and neutron star merger simulations based on the Virial expansion at low densities, and large scale relativistic mean field calculations.

  13. 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

  14. 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

  15. Luminescence characterization of a sodium rich feldspar

    International Nuclear Information System (INIS)

    Correcher, V.; Sanchez M, L.; Garcia G, J.; Rivera, T.

    2006-01-01

    This paper reports on the radioluminescence (RL) and thermoluminescence (TL) properties of a sodium rich feldspar ((Na,K)[AlSi 3 O 8 ]) with a mean molecular composition of orthoclase (Or) and albite (Ab) of Or 1 Ab 99 . Despite the complexity of the luminescence signals of the sample, it is possible to determine six different emission bands at about 300, 380, 420, 460, 550 and 680 nm. The 300 nm emission can be associated to structural defects related to the recombination process in which the Na + ion diffusion-limited is involved. The UV-blue emission band at (i) 380 nm is characteristic of mineral phases containing SiO 4 tetrahedral and could be related to intrinsic defects in the lattice, (ii) the 420 nm band could be associated to the presence of Cu (II) ions placed next to the hole traps or the recombination on a centre formed from a hole-oxygen atom adjacent to two Al atoms (Al-O-Al) and (iii) the 460 nm waveband could be due to the presence of Ti 4+ . The green and red emissions are respectively associated to the presence of Mn 2+ and Fe 3+ ions. The ratio between the relative intensities, peaked at 290 (the more intense waveband) and 550 nm is about 10:1 in both TL and RL; this fact indicates that the efficiency of recombination centres does no changes regardless on the type of the process. (Author)

  16. 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)

  17. The neutrino opacity of neutron rich matter

    Energy Technology Data Exchange (ETDEWEB)

    Alcain, P.N., E-mail: pabloalcain@gmail.com [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina); Dorso, C.O. [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina)

    2017-05-15

    The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are expected to exist in these systems, often referred to as nuclear pasta. We have carried out a systematic study of neutrino opacity for different thermodynamic conditions in order to assess the impact that the structure has on it. We studied the dynamics of the neutrino opacity of the heterogeneous matter at different thermodynamic conditions with semiclassical molecular dynamics model already used to study nuclear multifragmentation. For different densities, proton fractions and temperature, we calculate the very long range opacity and the cluster distribution. The neutrino opacity is of crucial importance for the evolution of the core-collapse supernovae and the neutrino scattering.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    Neutron-rich Dy isotopes; high-spin states; g-factors; cranked HFB theory. ... for 164Dy marking a clear separation in the behaviour as a function of neutron ... cipal x-axis as the cranking axis) in this mass region we have planned to make a sys-.

  3. Fission decay properties of ultra neutron-rich uranium isotopes

    Indian Academy of Sciences (India)

    in the chain of neutron-rich uranium isotopes is examined here. The neutron ... mean field theory, this nucleus is shown to undergo exotic decay mode of thermal neu- .... For 250U with a fission barrier of 4.3 MeV [5], we obtain the value of.

  4. Small angle neutron scattering studies of mixed micelles of sodium

    Indian Academy of Sciences (India)

    The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long rod-shaped micelles with ...

  5. Measurement of the neutron total cross section of sodium

    International Nuclear Information System (INIS)

    Larson, D.C.; Harvey, J.A.; Hill, M.W.

    1976-01-01

    The transmission of neutrons through a sample of pure sodium was measured in the energy range 40 keV to 20 MeV. The measurement points out several areas for improvement in the sodium evaluation for ENDF/B-V, the most important being the broadening of the minimum at 300 keV

  6. 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.))

  7. 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.

  8. 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.)

  9. 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.)

  10. Evolution of shell gaps with neutron richness

    International Nuclear Information System (INIS)

    Basu, Moumita Ray; Ray, I.; Kshetri, Ritesh; Saha Sarkar, M.; Sarkar, S.

    2006-01-01

    In the present work, an attempt has been made to coordinate the recent data available over the periodic table, specially near the shell gaps and studied the evolution of the shell gaps as function of neutron numbers and/or other related quantities

  11. Decay properties of some neutron-rich praseodymium isotopes

    International Nuclear Information System (INIS)

    Skarnemark, G.; Aronsson, P.O.; Stender, E.; Trautmann, N.; Kaffrell, N.; Bjoernstad, T.; Kvale, E.; Skarestad, M.

    1976-01-01

    Neutron-rich Pr isotopes produced in the thermal neutron-induced fission of 235 U have been investigated by means of γ-γ coincidence experiments. The nuclides have been separated from the fission product mixture, using the fast chemical separation system SISAK in connection with a gas jet recoil transport system. The results include assignments of several new γ-ray energies and partial decay schemes for 147 Pr, 148 Pr, 149 Pr and 150 Pr. (orig.) [de

  12. 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

  13. 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.

  14. 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

  15. 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

  16. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  17. Laser Spectroscopy of Neutron Rich Bismuth Isotopes

    CERN Multimedia

    2002-01-01

    %IS344 :\\\\ \\\\ The aim of the experiment is to measure the optical isotope shifts and hyperfine structures of bismuth isotopes across the N=126 shell closure in order to extract the change in mean square charge radii ($\\delta\\langle r^{2}\\rangle$) and static moments. These include the first isotones of lead to be measured directly above the shell closure and will provide new information on the systematics of the kink ($\\delta\\langle r^{2}\\rangle)$ seen in the lead isotopic chain. After two very successful runs the programme has been extended to include the neutron deficient isotopes below $^{201}$Bi to study the systematics across the $i_{13/2}$ neutron sub-shell closure at N=118.\\\\ \\\\ During the initial 2 runs (9 shifts) the isotope shifts and hyperfine structures of three new isotopes, $ ^{210,212,213}$Bi and the 9$^{-}$ isomer of $^{210}$Bi have been measured. The accuracy of the previous measurements of $^{205,206,208}$Bi have been greatly improved. The samples of $ ^{208,210,210^{m}}$Bi were prepared by c...

  18. 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...

  19. Recent results on neutron rich tin isotopes by laser spectroscopy

    CERN Document Server

    Roussière, B; Crawford, J E; Essabaa, S; Fedosseev, V; Geithner, W; Genevey, J; Girod, M; Huber, G; Horn, R; Kappertz, S; Lassen, J; Le Blanc, F; Lee, J K P; Le Scornet, G; Lettry, Jacques; Mishin, V I; Neugart, R; Obert, J; Oms, J; Ouchrif, A; Peru, S; Pinard, J; Ravn, H L; Sauvage, J; Verney, D

    2001-01-01

    Laser spectroscopy measurements have been performed on neutron rich tin isotopes using the COMPLIS experimental setup. The nuclear charge radii of the even-even isotopes from A=108 to 132 are compared to the results of macroscopic and microscopic calculations. The improvements and optimizations needed to perform the isotope shift measurement on $^{134}$Sn are presented.

  20. 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)

  1. Influence Of The Neutron Richness On Binary Decays

    Directory of Open Access Journals (Sweden)

    Roy R.

    2010-03-01

    Full Text Available The influence of the neutron richness on binary decays is investigated in 78,82Kr+ 40Ca reactions at 5.5 MeV/A incident energy. Kinetic energy distributions and angular distributions of fragments with atomic number 6 ≤ Z ≤ 28 were measured using the 4π-INDRA array. Global features are compatible with an emission from a long-lived system. The yields around the symmetric splitting are about 30The persistence of strong structural effects is evidenced from elemental cross-sections of the light fragments. The cross-sections for odd-Z fragments are higher for the neutron rich CN while cross-sections for even-Z fragments are higher for the neutron poor CN. Calculations assuming two different potential energy surfaces are presented.

  2. Neutron noise analysis for malfunction diagnosis at sodium cooled reactors

    International Nuclear Information System (INIS)

    Hoppe, P.

    1978-09-01

    For the investigation of the potential use of neutron noise analysis at sodium cooled power reactors, measurements have been performed at the KNK I reactor over a period of 18 month under different operational conditions. The signal fluctuations of the following tranducers have been recorded: In-core and Ex-core neutron detectors, temperature-, flow-, pressure-, vibration- and acoustic sensors. These extensive measurements have been analyzed in the frequency range from 0,001 Hz to 1000 Hz with all currently known methods for the identification of noise sources. The following results have been found: - Neutron noise for f 20 Hz the white detection noise prevails. In the region from 1 Hz to 20 Hz the vibrations of core components contribute to neutron noise. - Neutron noise is influenced by the state of the plant. - The contributions to neutron noise due to the fluctuations of coolant flow and inlet temperature are small compared to those produced by the movements of the control rod initiated by the reactor control system. The quantitatively unidentifiable amount of reactivity fluctuations (0,6 time-dependent thermal bowing of the core. With respect to these results and by calculation of the neutron noise patterns to be expected for the SNR 300, the following possible applications for neutron noise analysis have been found: By means of neutron noise analysis only reactivity fluctuations can be identified and supervised which are produced by time dependent changes of the core geometry. Furthermore neutron noise analysis is well suited for a sensitive detection of control rod vibrations and of local sodium boiling. Finally it can be used for the surveillance of the proper functioning of the reactor control system and of the control rod drive mechanism. (orig./HP) 891 HP [de

  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. 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.

  5. Thermonuclear runaways in thick hydrogen rich envelopes of neutron stars

    Science.gov (United States)

    Starrfield, S. G.; Kenyon, S.; Truran, J. W.; Sparks, W. M.

    1981-01-01

    A Lagrangian, fully implicit, one dimensional hydrodynamic computer code was used to evolve thermonuclear runaways in the accreted hydrogen rich envelopes of 1.0 Msub solar neutron stars with radii of 10 km and 20 km. Simulations produce outbursts which last from about 750 seconds to about one week. Peak effective temeratures and luninosities were 26 million K and 80 thousand Lsub solar for the 10 km study and 5.3 millison and 600 Lsub solar for the 20 km study. Hydrodynamic expansion on the 10 km neutron star produced a precursor lasting about one ten thousandth seconds.

  6. 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

  7. Experimental determination of one- and two-neutron separation energies for neutron-rich copper isotopes

    Science.gov (United States)

    Yu, Mian; Wei, Hui-Ling; Song, Yi-Dan; Ma, Chun-Wang

    2017-09-01

    A method is proposed to determine the one-neutron S n or two-neutron S 2n separation energy of neutron-rich isotopes. Relationships between S n (S 2n) and isotopic cross sections have been deduced from an empirical formula, i.e., the cross section of an isotope exponentially depends on the average binding energy per nucleon B/A. The proposed relationships have been verified using the neutron-rich copper isotopes measured in the 64A MeV 86Kr + 9Be reaction. S n, S 2n, and B/A for the very neutron-rich 77,78,79Cu isotopes are determined from the proposed correlations. It is also proposed that the correlations between S n, S 2n and isotopic cross sections can be used to find the location of neutron drip line isotopes. Supported by Program for Science and Technology Innovation Talents at Universities of Henan Province (13HASTIT046), Natural and Science Foundation in Henan Province (162300410179), Program for the Excellent Youth at Henan Normal University (154100510007) and Y-D Song thanks the support from the Creative Experimental Project of National Undergraduate Students (CEPNU 201510476017)

  8. 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.

  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. The electric dipole response of neutron rich tin isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Horvat, Andrea; Aumann, Thomas; Rossi, Dominic; Schindler, Fabia [Institut fuer Kernphysik, TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Johansen, Jacob [Aarhus University (Denmark); Schrock, Philipp [The University of Tokyo (Japan); Collaboration: R3B-Collaboration

    2016-07-01

    Studies of the dipole response in medium heavy and heavy neutron rich nuclei reveal valuable information about the isospin dependence of the nuclear equation of state. Therefore an experimental campaign investigating both the electric dipole response via Coulomb excitation and neutron removal along the tin isotope chain ({sup 124-134}Sn) has been carried out at the R3B (Reactions with Relativistic Radioactive Beams) setup at GSI (Helmholtzzentrum fuer Schwerionenforschung) for which the analysis is ongoing. The E1 response was induced via relativistic Coulomb scattering by a lead target in inverse kinematics, and calls for a kinematically complete determination of all reaction products in order to reconstruct the excitation energy by means of the invariant mass method. The goal is to obtain the Coulomb excitation cross section up to the adiabatic cut-off energy, covering the giant dipole resonance (GDR) range.

  11. 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

  12. Level structures of neutron-rich Xe isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Lister, C.J.; Morss, L.R. [and others

    1995-08-01

    The level structures of neutron-rich Xe isotopes were determined by observing prompt gamma-ray coincidences in {sup 248}Cm fission fragments. A 5-mg {sup 248}Cm, in the form of {sup 248}Cm-KCl pellet, was placed inside Eurogam array which consisted of 45 Compton-suppressed Ge detectors and 5 Low-Energy Photon Spectrometers. Transitions in Xe isotopes were identified by the appearance of new peaks in the {gamma}-ray spectra obtained by gating on the gamma peaks of the complementary Mo fragments.

  13. Determination of sodium in pharmaceuticals by neutron activation analysis

    International Nuclear Information System (INIS)

    Kanias, G.D.

    1985-01-01

    A simple, fast and accurate neutron activation analysis method for determination of Na in drugs concerning either active compound or total content was developed. The examined dosage forms consisted of 10 injectable ampoules and 10 bottles of oral solutions. The irradiation of samples and standards was carried out in the rotation system of the Reactor of Nuclear Research Center Democritos with maximal neutron flux of 2,9.10 13 n.cm -2 .sec -1 . Gamma-ray spectrometry of the irradiated samples and standards was accomplished with a coaxial Ge(Li) detector series Win 15 with an efficiency of 15% connected to an Ino-Tech 1024 channel analyser (Model IT 5200). The accuracy and precision of the method are found to be very high and therefore it could be established as an official one for the determination of sodium in parmaceuticals

  14. 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 ...

  15. Spectroscopy of neutron-rich isotopes of nickel and iron

    International Nuclear Information System (INIS)

    Girod, M.; Dessagne, P.; Bernas, M.; Langevin, M.; Pougheon, F.; Roussel, P.

    1987-01-01

    Spectroscopy of neutron rich isotopes of 67 Ni, 68 Ni and 62 Fe is studied using the quasi-elastic transfer reactions ( 14 C, 16 O) and ( 14 C, 17 O) on mass separated targets of 70 Zn and of 64 Ni. The structure of these new nuclei is investigated through the Hartree-Fock-Bogoliubov (HFB) calculations, using the D1SA interaction. Inertial parameters are calculated in the cranking approximation. Collective excited states are obtained consistently by solving the Bohr Hamiltonian. Based on these results, quantum numbers are tentatively assigned to the observed states and angular distributions, measured and calculated from the DWBA, are used to check this assignment. The spectroscopy of more neutron rich nuclei, yet unknown, is anticipated. A sharper test of wave functions is provided by the monopole operator of the O 2 + → O 1 + transition in 68 Ni, which have been deduced from the halflife measurement performed in delayed coincidence experiments. An impressive agreement is obtained between the measured halflife and its value calculated using complete HFB wave functions

  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. Unexpectedly large charge radii of neutron-rich calcium isotopes

    CERN Document Server

    Garcia Ruiz, R F; Blaum, K; Ekström, A; Frömmgen, N; Hagen, G; Hammen, M; Hebeler, K; Holt, J D; Jansen, G R; Kowalska, M; Kreim, K; Nazarewicz, W; Neugart, R; Neyens, G; Nörtershäuser, W; Papenbrock, T; Papuga, J; Schwenk, A; Simonis, J; Wendt, K A; Yordanov, D T

    2016-01-01

    Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain ‘magic’ numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known calcium isotopes have been successfully described by nuclear theory, it is still a challenge to predict the evolution of their charge radii. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-...

  18. 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.

  19. Weakly bound structures in neutron rich Si isotopes

    International Nuclear Information System (INIS)

    Singh, D.; Saxena, G.; Yadav, H.L.

    2009-01-01

    Production of radioactive beams have facilitated the nuclear structure studies away from the line of β-stability, especially for the neutron rich drip line nuclei. Theoretical investigations of these nuclei have been carried out by using various approaches viz. few body model or clusters, shell model and mean field theories, both nonrelativistic as well as relativistic mean field (RMF). The advantage of the RMF approach, however, is that in this treatment the spin-orbit interaction is included in a natural way. This is especially advantageous for the description of drip-line nuclei for which the spin-orbit interaction plays an important role. In this communication we report briefly the results of our calculations for the Si isotopes carried out within the framework of RMF + BCS approach

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Radiochemical search for neutron-rich isotopes of element 107

    International Nuclear Information System (INIS)

    Schaedel, M.

    1987-01-01

    Recent mass calculations have indicated that there is a region of deformed nuclei around neutron number N=162 that is especially stable against spontaneous fission. Barrier heights of about 5 MeV for Z = 107 nuclides can be extrapolated. To search for new, neutron-rich isotopes of element 107 in radiochemical experiments with 254 Es as a target an on-line chemical separation of element 107 (EKA-Rhenium), especially from the actinide elements is needed. An on-line gas-phase chemistry was developed with the homolog Re based on the volatility of the oxide which is transported in an O 2 containing atmosphere along a temperature gradient in a quartz tube and is condensed onto a thin Ta coated Ni-foil. The authors applied this technique in two series of experiments with their rotating wheel on-line gas-phase chemistry apparatus at the 88-inch cyclotron where they irradiated 254 Es as a target with 93 MeV and 96 MeV 16 O ions to search for 266 107. The assignment of the observed alpha events between 8 and 9 MeV to possibly (1) non actinide contaminants like 212 Po, (2) known isotopes of heavy elements like 261 105, or (3) a new isotope will be discussed

  6. 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.

  7. 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)

  8. Possibilities of production of neutron-rich Md isotopes in multi-nucleon transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Myeong-Hwan; Lee, Young-Ouk [Korea Atomic Energy Research Institue, Daejeon (Korea, Republic of); Adamian, G.G.; Antonenko, N.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-12-15

    The possibilities of production of yet unknown neutron-rich isotopes of Md are explored in several multi-nucleon transfer reactions with actinide targets and stable and radioactive beams. The projectile-target combinations and bombarding energies are suggested to produce new neutron-rich isotopes of Md in future experiments. (orig.)

  9. 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.

  10. 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

  11. Photo-neutron cross sections for unstable neutron-rich oxygen isotopes

    International Nuclear Information System (INIS)

    Leistenschneider, A.; Aumann, T.; Boretzky, K.

    2001-05-01

    The dipole response of stable and unstable neutron-rich oxygen nuclei of masses A = 17 to A = 22 has been investigated experimentally utilizing electromagnetic excitation in heavy-ion collisions at beam energies around 600 MeV/nucleon. A kinematically complete measurement of the neutron decay channel in inelastic scattering of the secondary beam projectiles from a Pb target was performed. Differential electromagnetic excitation cross sections dσ/dE were derived up to 30 MeV excitation energy. In contrast to stable nuclei, the deduced dipole strength distribution appears to be strongly fragmented and systematically exhibits a considerable fraction of low-lying strength, exhausting up to 12% of the energy-weighted dipole sum rule at excitation energies below 15 MeV. (orig.)

  12. Exploring Neutron-Rich Oxygen Isotopes with MoNA

    International Nuclear Information System (INIS)

    Frank, N.; Gade, A.; Peters, W. A.; Thoennessen, M.; Baumann, T.; Bazin, D.; Lecouey, J.-L.; Scheit, H.; Schiller, A.; Brown, J.; DeYoung, P. A.; Finck, J. E.; Hinnefeld, J.; Howes, R.; Luther, B.

    2007-01-01

    The Modular Neutron Array (MoNA) was used in conjunction with a large-gap dipole magnet (Sweeper) to measure neutron-unbound states in oxygen isotopes close to the neutron dripline. While no excited states were observed in 24 O, a resonance at 45(2) keV above the neutron separation energy was observed in 23 O

  13. Solid thermoluminescent dosemeter of sodium tetraborate and brazilian fluoride sensitive to thermal neutrons

    International Nuclear Information System (INIS)

    Fratin, L.

    1988-01-01

    The techniques of compacting sodium tetraborate and natural fluoride mixtures were studied in this work, with the aim of producing a solid dosimeter sensitive to thermal neutrons. The production procedure involves the vitrification of the sodium tetraborate, the grinding, mixture, cold pressing and the sinterization of the pellets. A special arrangement was built for irradiation where paraffin was used as moderator for neutrons from a 241 Am-Be source. Two different mass ratios of sodium tetraborate and flourite showed a linear thermoluminescent response to the neutron fluence in the range of 1.0 to 7.0 x 10 8 n (sub)tcm -2 . Solid dosimeters, manufactured from natural fluorite and sodium chloride, showed a response to gamma radiation similar to the response of the dosimeters sensitive to neutrons. These dosimeters are need to identify the proportion of thermoluminescent response due to gamma radiation present in a neutron field. (author) [pt

  14. Transition probabilities in neutron-rich Se,8684

    Science.gov (United States)

    Litzinger, J.; Blazhev, A.; Dewald, A.; Didierjean, F.; Duchêne, G.; Fransen, C.; Lozeva, R.; Sieja, K.; Verney, D.; de Angelis, G.; Bazzacco, D.; Birkenbach, B.; Bottoni, S.; Bracco, A.; Braunroth, T.; Cederwall, B.; Corradi, L.; Crespi, F. C. L.; Désesquelles, P.; Eberth, J.; Ellinger, E.; Farnea, E.; Fioretto, E.; Gernhäuser, R.; Goasduff, A.; Görgen, A.; Gottardo, A.; Grebosz, J.; Hackstein, M.; Hess, H.; Ibrahim, F.; Jolie, J.; Jungclaus, A.; Kolos, K.; Korten, W.; Leoni, S.; Lunardi, S.; Maj, A.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Mijatovic, T.; Million, B.; Möller, O.; Modamio, V.; Montagnoli, G.; Montanari, D.; Morales, A. I.; Napoli, D. R.; Niikura, M.; Pollarolo, G.; Pullia, A.; Quintana, B.; Recchia, F.; Reiter, P.; Rosso, D.; Sahin, E.; Salsac, M. D.; Scarlassara, F.; Söderström, P.-A.; Stefanini, A. M.; Stezowski, O.; Szilner, S.; Theisen, Ch.; Valiente Dobón, J. J.; Vandone, V.; Vogt, A.

    2015-12-01

    Reduced quadrupole transition probabilities for low-lying transitions in neutron-rich Se,8684 are investigated with a recoil distance Doppler shift (RDDS) experiment. The experiment was performed at the Istituto Nazionale di Fisica Nucleare (INFN) Laboratori Nazionali di Legnaro using the Cologne Plunger device for the RDDS technique and the AGATA Demonstrator array for the γ -ray detection coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In 86Se the level lifetime of the yrast 21+ state and an upper limit for the lifetime of the 41+ state are determined for the first time. The results of 86Se are in agreement with previously reported predictions of large-scale shell-model calculations using Ni78-I and Ni78-II effective interactions. In addition, intrinsic shape parameters of lowest yrast states in 86Se are calculated. In semimagic 84Se level lifetimes of the yrast 41+ and 61+ states are determined for the first time. Large-scale shell-model calculations using effective interactions Ni78-II, JUN45, jj4b, and jj4pna are performed. The calculations describe B (E 2 ;21+→01+) and B (E 2 ;61+→41+) fairly well and point out problems in reproducing the experimental B (E 2 ;41+→21+) .

  15. Delayed Particle Study of Neutron Rich Lithium Isotopes

    CERN Multimedia

    Marechal, F; Perrot, F

    2002-01-01

    We propose to make a systematic complete coincidence study of $\\beta$-delayed particles from the decay of neutron-rich lithium isotopes. The lithium isotopes with A=9,10,11 have proven to contain a vast information on nuclear structure and especially on the formation of halo nuclei. A mapping of the $\\beta$-strength at high energies in the daughter nucleus will make possible a detailed test of our understanding of their structure. An essential step is the comparison of $\\beta$-strength patterns in $^{11}$Li and the core nucleus $^{9}$Li, another is the full characterization of the break-up processes following the $\\beta$-decay. To enable such a measurement of the full decay process we will use a highly segmented detection system where energy and emission angles of both charged and neutral particles are detected in coincidence and with high efficiency and accuracy. We ask for a total of 30 shifts (21 shifts for $^{11}$Li, 9 shifts $^{9}$Li adding 5 shifts for setting up with stable beam) using a Ta-foil target...

  16. Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors; Visualisation ultrasonore rapide sous sodium. application aux reacteurs a neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Imbert, Ch

    1997-05-30

    The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

  17. Study of neutron-rich $^{51−53}$ Ca isotopes via $\\beta$-decay

    CERN Multimedia

    The high Q$_\\beta$ values in certain neutron-rich regions of the chart of nuclides opens up the possibility to study states in the daughter nuclei which lie at high excitation energy, above the neutron separation threshold. We propose to perform spectroscopy of the $\\beta$-delayed neutron emission of the $^{51-53}$K isotopes to study the population of single-particle or particle-hole states both below and above the neutron separation threshold. The VANDLE neutron detector will be used in combination with the IDS tape station setup and Ge detectors.

  18. Structure of the neutron-rich lithium isotopes in heavy-ion reactions

    International Nuclear Information System (INIS)

    Bespalova, O.V.; Galakhmatova, B.S.; Romanovskij, E.A.; Shitikova, K.V.; Burov, V.V.; Rzyanin, M.V.; Miller, H.G.; Yen, G.D.

    1993-01-01

    The structure properties, for factors, angular distributions and interaction cross sections of Li neutron-rich isotopes have been analyzed in the unified way. A good qualitative agreement with the experiment data was obtained. 20 refs.; 11 figs.; 1 tab

  19. 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

  20. 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

  1. 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 ...

  2. 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

  3. Constraining the EOS of Neutron-Rich Nuclear Matter and Properties of Neutron Stars with Heavy-Ion Reactions

    International Nuclear Information System (INIS)

    Li Baoan; Worley, Aaron; Chen, L.-W.; Ko, Che Ming; Krastev, Plamen G.; Wen Dehua; Xiao Zhigang; Zhang Ming; Xu Jun; Yong Gaochan

    2009-01-01

    Heavy-ion reactions especially those induced by radioactive beams provide useful information about the density dependence of the nuclear symmetry energy, thus the Equation of State of neutron-rich nuclear matter, relevant for many astrophysical studies. The latest developments in constraining the symmetry energy at both sub- and supra-saturation densities from analyses of the isopsin diffusion and the π - /π + ratio in heavy-ion collisions using the IBUU04 transport model are discussed. Astrophysical ramifications of the partially constrained symmetry energy on properties of neutron star crusts, gravitational waves emitted by deformed pulsars and the w-mode oscillations of neutron stars are presented briefly.

  4. 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.

  5. Normal levels of total body sodium and chlorine by neutron activation analysis

    International Nuclear Information System (INIS)

    Kennedy, N.S.J.; Eastell, R.; Smith, M.A.; Tothill, P.

    1983-01-01

    In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation of normalised sodium was 5.9% in men and 6.9% in women, and of normalised chlorine 9.3% in men and 5.5% in women. In the range examined (40-70 years) no significant age dependence was observed for either element. Total body sodium was correlated with total body chlorine and total body calcium. Sodium excess, defined as the amount of body sodium in excess of that associated with chlorine, also correlated well with total body calcium. In females there was a mean annual loss of sodium excess of 1.2% after the menopause, similar to the loss of calcium. (author)

  6. 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.

  7. Effect of Neutron Irradiation on the Physicochemical Properties of Naproxen Sodium

    International Nuclear Information System (INIS)

    Ibrahim Ijang

    2016-01-01

    Complex dosage forms may be designed to provide sustained release of the drug or to deliver the active ingredients to the specific sites. It is important to know the in-vivo behaviour of the drug formulation following administration. Gamma scintigraphy technique has been widely used to monitor the in-vivo radiopharmaceuticals dosage form by neutron activation. This study was to investigate effect of neutron activation on the physicochemical properties of the Naproxen Sodium as a model drug. The drug was irradiated using TRIGA MK II reactor with thermal neutron at 1.2 x 10"1"2 neutron cm"-"2s"-"1 for 1, 2, 3, 4, 5 and 30 minutes. The stability of naproxen sodium was assessed based on the malting point, morphology, Gas Chromatograph-Mass Spectrometer (GC-MS) and Fourier Transform Infrared Spectrometer (FTIR). Results of analysis of Scanning Electron Microscope (SEM) and FTIR showed changes in the physicochemical properties of naproxen sodium when duration of irradiation was increased. There were no major changes in the result of GC-MS and Differential Scanning Calorimeter (DSC). Based on the results obtained, it be concluded that naproxen sodium is a suitable drug that can be used for neutron activation based gamma scintigraphy. The maximum irradiation time that naproxen sodium can be withstand without changes in its physicochemical properties is 3 minutes. (author)

  8. 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

  9. Goodness of isospin in neutron rich systems from the fission fragment distribution

    Science.gov (United States)

    Garg, Swati; Jain, Ashok Kumar

    2017-09-01

    We present the results of our calculations for the relative yields of neutron-rich fission fragments emitted in 208Pb (18O, fission) reaction by using the concept of the conservation of isospin and compare with the experimental data. We take into account a range of isospin values allowed by the isospin algebra and assume that the fission fragments are formed in isobaric analog states. We also take into account the neutron multiplicity data for various neutron-emission channels in each partition, and use them to obtain the weight factors in calculating the yields. We then calculate the relative yields of the fission fragments. Our calculated results are able to reproduce the experimental trends reasonably well. This is the first direct evidence of the isospin conservation in neutron-rich systems and may prove a very useful tool in their studies.

  10. Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors

    International Nuclear Information System (INIS)

    Imbert, Ch.

    1997-01-01

    The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

  11. 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

  12. Radioactivity of neutron rich oxygen, fluorine and neon isotopes

    International Nuclear Information System (INIS)

    Reed, A.T.; Page, R.D.; Tarasov, O.

    1999-01-01

    The γ-radiation and neutrons emitted following the β-decays of 24 O, 25-27 F and 28-30 Ne have been measured. The nuclides were produced in the quasi-fragmentation of a 78 MeV/A 36 S beam, separated in-flight and identified through time-of-flight and energy loss measurements. The ions were stopped in a silicon detector system, which was used to detect the β-particles emitted in their subsequent radioactive decay. The coincident γ-rays were measured using four large Ge detectors mounted close to the implantation point and the neutrons were detected using forty-two 3 He proportional counters. The measured γ-ray energy spectra are compared with shell model calculations and, where available, the level energies are deduced from transfer reactions

  13. Development of a Neutron Flux Monitoring System for Sodium-cooled Fast Reactors

    OpenAIRE

    Verma, Vasudha

    2017-01-01

    Safety and reliability are one of the key objectives for future Generation IV nuclear energy systems. The neutron flux monitoring system forms an integral part of the safety design of a nuclear reactor and must be able to detect any irregularities during all states of reactor operation. The work in this thesis mainly concerns the detection of in-core perturbations arising from unwanted movements of control rods with in-vessel neutron detectors in a sodium-cooled fast reactor. Feasibility stud...

  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. Laser-spectroscopy studies of the nuclear structure of neutron-rich radium

    Science.gov (United States)

    Lynch, K. M.; Wilkins, S. G.; Billowes, J.; Binnersley, C. L.; Bissell, M. L.; Chrysalidis, K.; Cocolios, T. E.; Goodacre, T. Day; de Groote, R. P.; Farooq-Smith, G. J.; Fedorov, D. V.; Fedosseev, V. N.; Flanagan, K. T.; Franchoo, S.; Garcia Ruiz, R. F.; Gins, W.; Heinke, R.; Koszorús, Á.; Marsh, B. A.; Molkanov, P. L.; Naubereit, P.; Neyens, G.; Ricketts, C. M.; Rothe, S.; Seiffert, C.; Seliverstov, M. D.; Stroke, H. H.; Studer, D.; Vernon, A. R.; Wendt, K. D. A.; Yang, X. F.

    2018-02-01

    The neutron-rich radium isotopes, Ra-233222, were measured with Collinear Resonance Ionization Spectroscopy (CRIS) at the ISOLDE facility, CERN. The hyperfine structure of the 7 s2S10→7 s 7 p P31 transition was probed, allowing measurement of the magnetic moments, quadrupole moments, and changes in mean-square charge radii. These results are compared to existing literature values, and the new moments and change in mean-square charge radii of 231Ra are presented. Low-resolution laser spectroscopy of the very neutron-rich 233Ra has allowed the isotope shift and relative charge radius to be determined for the first time.

  16. 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...

  17. 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

  18. 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

  19. Small-angle neutron scattering studies of sodium butyl benzene

    Indian Academy of Sciences (India)

    Na-NBBS), in aqueous solutions is investigated by small-angle neutron scattering (SANS). Nearly ellipsoidal aggregates of Na-NBBS at concentrations well above its minimum hydrotrope concentration were detected by SANS. The hydrotrope ...

  20. Neutron-absorption cross section of sodium-22

    International Nuclear Information System (INIS)

    Rundberg, R.; Elgart, M.F.; Finston, H.L.; Williams, E.T.; Bond, A.H. Jr.

    1975-01-01

    A simple method for determining the neutron-absorption cross sections for radionuclides produced and consumed in a reactor-neutron flux is described. Data were obtained for 22 Na which, through application of Westcott's procedure, yielded the following: sigma 0 = 51.5 +- 3.1 kbarns, s 0 = 2.3 +- 0.1, and Σ' = 100 +- 10 kbarns. (3 tables) (U.S.)

  1. Light neutron-rich hypernuclei from the importance-truncated no-core shell model

    Directory of Open Access Journals (Sweden)

    Roland Wirth

    2018-04-01

    Full Text Available We explore the systematics of ground-state and excitation energies in singly-strange hypernuclei throughout the helium and lithium isotopic chains — from HeΛ5 to HeΛ11 and from LiΛ7 to LiΛ12 — in the ab initio no-core shell model with importance truncation. All calculations are based on two- and three-baryon interaction from chiral effective field theory and we employ a similarity renormalization group transformation consistently up to the three-baryon level to improve the model-space convergence. While the absolute energies of hypernuclear states show a systematic variation with the regulator cutoff of the hyperon–nucleon interaction, the resulting neutron separation energies are very stable and in good agreement with available data for both nucleonic parents and their daughter hypernuclei. We provide predictions for the neutron separation energies and the spectra of neutron-rich hypernuclei that have not yet been observed experimentally. Furthermore, we find that the neutron drip lines in the helium and lithium isotopic chains are not changed by the addition of a hyperon. Keywords: Hypernuclei, Ab-initio methods, Neutron-rich nuclei, Neutron separation energies, Neutron drip line

  2. Nuclear reactions of neutron-rich Sn isotopes investigated at relativistic energies at R{sup 3}B

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Fabia; Aumann, Thomas; Horvat, Andrea [TU Darmstadt (Germany); Boretzky, Konstanze [GSI Helmholtzzentrum (Germany); Schrock, Philipp [CNS, University of Tokyo (Japan); Johansen, Jacob [Aarhus University (Denmark); Collaboration: R3B-Collaboration

    2016-07-01

    Nuclei with a large neutron excess are expected to form a neutron-rich surface layer which is often referred to as the neutron skin. The investigation of this phenomenon is of great interest in nuclear-structure physics and offers a possibility to constrain the equation-of-state of neutron-rich matter. Assuming a geometrical description of reaction processes as in the eikonal approximation, nuclear-induced reactions are a good tool to probe the neutron skin. Measured reaction cross sections can be used to constrain the density distributions of protons and neutrons in the nucleus and therefore the neutron-skin thickness. For this purpose, reactions of neutron-rich tin isotopes in the A=124-134 mass range have been measured on a carbon target at the R{sup 3}B-setup at GSI in inverse kinematics in a kinematically complete manner. Preliminary results for the reaction cross sections of {sup 124}Sn are presented.

  3. Identification of new neutron-rich actinide isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Oura, Yasuji; Sakama, Minoru; Ohyama, T. [Tokyo Metropolitan Univ. (Japan)] [and others

    1999-10-01

    To advance research on new neutron-deficient actinide isotopes using an on-line isotope separator combined with a gas-jet injector installed in the JAERI Tandem accelerator, Tokai, performance test of the equipment was carried out. Efficiency of the product isotopes being transported from the target chamber to the measuring system was greatly improved by employing lead iodides (PbI{sub 2}) as the aerosol carrier. With the help of this technique, the authors succeeded in synthesizing and identifying actinide isotopes, {sup 235}Am and {sup 236}Am, and measured their alpha-decay half-life. (S. Ohno)

  4. Improvement of Sodium Neutronic Nuclear Data for the Computation of Generation IV Reactors

    International Nuclear Information System (INIS)

    Archier, P.

    2011-01-01

    The safety criteria to be met for Generation IV sodium fast reactors (SFR) require reduced and mastered uncertainties on neutronic quantities of interest. Part of these uncertainties come from nuclear data and, in the particular case of SFR, from sodium nuclear data, which show significant differences between available international libraries (JEFF-3.1.1, ENDF/B-VII.0, JENDL-4.0). The objective of this work is to improve the knowledge on sodium nuclear data for a better calculation of SFR neutronic parameters and reliable associated uncertainties. After an overview of existing 23 Na data, the impact of the differences is quantified, particularly on sodium void reactivity effects, with both deterministic and stochastic neutronic codes. Results show that it is necessary to completely re-evaluate sodium nuclear data. Several developments have been made in the evaluation code Conrad, to integrate new nuclear reactions models and their associated parameters and to perform adjustments with integral measurements. Following these developments, the analysis of differential data and the experimental uncertainties propagation have been performed with Conrad. The resolved resonances range has been extended up to 2 MeV and the continuum range begins directly beyond this energy. A new 23 Na evaluation and the associated multigroup covariances matrices were generated for future uncertainties calculations. The last part of this work focuses on the sodium void integral data feedback, using methods of integral data assimilation to reduce the uncertainties on sodium cross sections. This work ends with uncertainty calculations for industrial-like SFR, which show an improved prediction of their neutronic parameters with the new evaluation. (author) [fr

  5. Quick evaluation of the neutron dose following a criticality accident by measurement of sodium 24 activity

    International Nuclear Information System (INIS)

    Tabardel, R.; Ricourt, A.; Parmentier, N.

    1984-07-01

    In order to quickly sort out the irradiated individuals following a criticality accident, the neutron dose can be evaluated quickly by measuring the sodium-24 activity induced in the human body. The report supplies the information necessary for this evaluation from the response of various detectors of current use in radiation protection. The first part describes the method of evaluation of sodium-24 activity (A) given by the reading (M) of each instrument. The second part describes the method of kerma evaluation from the measured sodium-24 activity. The third part is an experimental application of the method of kerma evaluation from the sodium-24 activity measured in a phantom irradiated in the SILENE reactor flux. The results given by radiation protection instruments are in good agreement with the calculated values for a front exposure and demonstrate the usefulness of measuring the induced sodium-24 activity by radiation protection instruments of current use [fr

  6. Accounting for Electronic Polarization Effects in Aqueous Sodium Chloride via Molecular Dynamics Aided by Neutron Scattering

    Czech Academy of Sciences Publication Activity Database

    Kohagen, Miriam; Mason, Philip E.; Jungwirth, Pavel

    2016-01-01

    Roč. 120, č. 8 (2016), s. 1454-1460 ISSN 1520-6106 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : molecular dynamics * neutron scattering * agueous sodium chloride Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.177, year: 2016

  7. 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

  8. 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.

  9. 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.

  10. Examination of different strengths of octupole correlations in neutron-rich Pr and Pm isotopes

    Czech Academy of Sciences Publication Activity Database

    Thiamova, G.; Alexa, P.; Hons, Zdeněk; Simpson, G.S.

    2012-01-01

    Roč. 86, č. 4 (2012), 044334/1-044334/5 ISSN 0556-2813 R&D Projects: GA ČR GAP203/10/0310 Institutional support: RVO:61389005 Keywords : neutron rich nuclei * octupole correlations Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.715, year: 2012

  11. 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

  12. 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

  13. 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)

  14. Nuclear structure far from stability: the neutron-rich 69-79Cu isotopes

    International Nuclear Information System (INIS)

    Franchoo, Serge

    2015-01-01

    Far from stability, the nuclear structure that is predicted by the shell model is evolving. Old magic numbers disappear, while new ones appear. Our understanding of the underlying nuclear force that drives these changes is still incomplete. After a short overview across the nuclear chart, we discuss the strength functions of the shell-model orbitals in the neutron-rich copper isotopes towards the 78 Ni doubly-magic nucleus. These were measured in a 72 Zn(d, 3 He) 71 Cu proton pick-up reaction in inverse kinematics with a radioactive beam at the Ganil laboratory in France. We also present the latest results from a 80 Zn(p,2p) 79 Cu knockout experiment at Riken in Japan, leading to selective population of hole states in 79 Cu. Our findings show that the Z=28 shell gap in the neutron-rich copper isotopes is surprisingly steady against the addition of neutrons beyond N=40. (author)

  15. Solid thermoluminescent dosemeter of sodium tetraborate and brazilian fluorite sensible to thermal neutrons

    International Nuclear Information System (INIS)

    Fratin, L.; Cruz, M.T. da

    1987-01-01

    A solid termoluminescent dosemeter of sodium tetraborate and brazilian fluorite sensible to thermal neutrons is described. The nuclears reactions 1) 10 B + n → 7 Li + He + Q1 (6,1%) where: Q1=2,79 MeV and Eα1 = 1,758 MeV and 2) 10 B + n → 7 Li* + 4 He + Q2 (93,9%) where: Q2 = 2,316 MeV and E2α 2 = 1,474 MeV are responsible by the thermoluminescent response of the thermal neutrons dosemeters. The stages in the fabrication process of this dosemeter of which are:1) sodium tetraborate vitrification, 2) mixture and pressing 3) sintering are cited. The obtainment of a natural fluorite dosemeter with sodium chloride is also shown. (C.G.C.) [pt

  16. 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)

  17. 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...

  18. Hydrogen substituted graphdiyne as carbon-rich flexible electrode for lithium and sodium ion batteries.

    Science.gov (United States)

    He, Jianjiang; Wang, Ning; Cui, Zili; Du, Huiping; Fu, Lin; Huang, Changshui; Yang, Ze; Shen, Xiangyan; Yi, Yuanping; Tu, Zeyi; Li, Yuliang

    2017-10-27

    Organic electrodes are potential alternatives to current inorganic electrode materials for lithium ion and sodium ion batteries powering portable and wearable electronics, in terms of their mechanical flexibility, function tunability and low cost. However, the low capacity, poor rate performance and rapid capacity degradation impede their practical application. Here, we concentrate on the molecular design for improved conductivity and capacity, and favorable bulk ion transport. Through an in situ cross-coupling reaction of triethynylbenzene on copper foil, the carbon-rich frame hydrogen substituted graphdiyne film is fabricated. The organic film can act as free-standing flexible electrode for both lithium ion and sodium ion batteries, and large reversible capacities of 1050 mAh g -1 for lithium ion batteries and 650 mAh g -1 for sodium ion batteries are achieved. The electrode also shows a superior rate and cycle performances owing to the extended π-conjugated system, and the hierarchical pore bulk with large surface area.

  19. In vitro effect of sodium nitrite on platelet aggregation in human platelet rich plasma--preliminary report.

    Science.gov (United States)

    Kadan, M; Doğanci, S; Yildirim, V; Özgür, G; Erol, G; Karabacak, K; Avcu, F

    2015-10-01

    The role of nitrates and nitric oxide on platelet functions has obtained an increasing attention with respect to their potential effects on cardiovascular disorders. In this study we aimed to analyze the effect of sodium nitrite on platelet functions in human platelets. This in vitro study was designed to show the effect of sodium nitrite on platelet functions in seven healthy volunteers. Blood samples were centrifuged to prepare platelet rich plasma and platelet poor plasma. Platelet rich plasma was diluted with the platelet poor plasma to have a final count of 300,000 ± 25,000 platelets. Platelet rich plasma was incubated with six different increasing doses (from 10 μM to 5 mM) of sodium nitrite for 1 hour at 37°C. Then stimulating agents including collagen (3 μg ml-1), adenosine diphosphate (10 μM), and epinephrine (10 μM) were added to the cuvette. Changes in light transmission were observed for 10 minutes. In addition spontaneous aggregation were performed in control group with all aggregating agents separately. Effect of sodium nitrite on agonist-induced platelet aggregation depends on the concentration of sodium nitrite. Compared with control group, agonist-induced platelet aggregations were significantly suppressed by sodium nitrite at the concentration of 5, 1.0 and 0.5 mM. Our results suggested that sodium nitrite has inhibitory effects in vitro on platelet aggregation in a dose-dependent manner.

  20. Determination of sodium in biological samples by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Parwate, D.V.; Garg, A.N.

    1981-01-01

    Sodium is one of the most essential elements needed for metabolic processes amongst human beings. It is consumed in the form of sodium chloride but it is also present in edible plant leaves. Sodium is mostly analyzed by flame photometric method, a destructive and time consuming technique. Sodium has been determined in some green leave vegetables samples-palak, radish, khatta palak (ambat chuka), chaulai leaves, chauli bean covers and its seeds by instrumental neutron activation analysis. The method involves irradiation of samples with thermal neutrons from 241 Am-Be source and counting 24 Na activity (half life 15 hr) from the reaction 23 Na(n,γ) 24 Na. Activity due to 1.37 MeV photopeak was counted with a NaI(Tl) crystal coupled to gamma ray spectrometer. Green leaves of the vegetables were thoroughly washed, dried at constant temperature and powdered. Bowen's Kale powder was used as standard for measuring sodium abundances. About 2g each of samples and the standard were packed in polythene vials. They were irradiated for 24 hrs, delayed by 1 hr and then counted for 20 mts. It is found that radish leaves are most enriched in sodium (14.0 +-0.45%) amongst four leave samples analyzed. For three different parts of chaulai leaves, bean covers and seeds, sodium contents are 1.38%, 1820 and 1010 ppm. Palak contains 2.84 +-0.29% while khatta palak contains only 4210 +- 830 ppm sodium. All values reported here are for dry weight samples and are means of three replicate measurements with standard deviation. (author)

  1. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ch

    2000-09-15

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

  2. β decay and isomeric properties of neutron-rich Ca and Sc isotopes

    International Nuclear Information System (INIS)

    Crawford, H. L.; Mantica, P. F.; Berryman, J. S.; Stoker, J. B.; Janssens, R. V. F.; Carpenter, M. P.; Kay, B. P.; Lauritsen, T.; Zhu, S.; Broda, R.; Cieplicka, N.; Fornal, B.; Grinyer, G. F.; Minamisono, K.; Hoteling, N.; Stefanescu, I.; Walters, W. B.

    2010-01-01

    The isomeric and β-decay properties of neutron-rich 53-57 Sc and 53,54 Ca nuclei near neutron number N=32 are reported, and the low-energy level schemes of 53,54,56 Sc and 53-57 Ti are presented. The low-energy level structures of the 21 Sc isotopes are discussed in terms of the coupling of the valence 1f 7/2 proton to states in the corresponding 20 Ca cores. Implications with respect to the robustness of the N=32 subshell closure are discussed, as well as the repercussions for a possible N=34 subshell closure.

  3. High-accuracy mass measurements of neutron-rich Kr isotopes

    CERN Document Server

    Delahaye, P; Blaum, K; Carrel, F; George, S; Herfurth, F; Herlert, A; Kellerbauer, A G; Kluge, H J; Lunney, D; Schweikhard, L; Yazidjian, C

    2006-01-01

    The atomic masses of the neutron-rich krypton isotopes 84,86-95Kr have been determined with the tandem Penning trap mass spectrometer ISOLTRAP with uncertainties ranging from 20 to 220 ppb. The masses of the short-lived isotopes 94Kr and 95Kr were measured for the first time. The masses of the radioactive nuclides 89Kr and 91Kr disagree by 4 and 6 standard deviations, respectively, from the present Atomic-Mass Evaluation database. The resulting modification of the mass surface with respect to the two-neutron separation energies as well as implications for mass models and stellar nucleosynthesis are discussed.

  4. Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Chakraborty S.

    2014-03-01

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

  5. Simulation for sodium-24 production using cyclic neutron activation analysis

    International Nuclear Information System (INIS)

    Ahamed, O. M. H.

    2012-04-01

    The cyclic neutron activation analysis is a method for elemental analysis which is preferred to use short-lived radio-nuclides. In recent years this method became a new application for radioisotope production especially in low power research reactors. In this study instrumental cyclic neutron activation analysis was used for 2 4N a production using 2 3N a (n, γ) 2 4N a reaction. The simplified westcott convention method is used neutron activation analysis in a research reactor. The method takes into account all corrections that can affect that yield created. In this work a model was devolving for calculations through this simplified Westcott convention method by using C++ program and selecting good parameters that can produce the expected activity. The simulation is used for the theoretical yield calculated has been validated by data from the 1 77L u production used for theoretical yield which it gives the approached result had been obtained by FORTRAN 90 from literature (8). The results were achieved for expected activity at full power (1 x 10 1 2n cm -2 s - 1 ) and half power (5 x 10 11 cm -2 s -1 ) for research reactor MNSR. The activity at full power was equal to about twice the activity at half power ( 49±7, 24.9 ± MBq/g), respectively. The irradiation parameters selected were irradiation time 4 min and decay time 12 min. Sample weight was 50 mg at 12 numbers of cycles, when the K-factor was equal to 1.74. This work is considered as first step for production of 2 4N a which can use such parameters experimentally. It is then possible to compare the expected activity with measured activity. (Author)

  6. Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

    International Nuclear Information System (INIS)

    Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A.M.; Beard, Mary; Brown, Edward; Bazin, D.; Becerril, A.; Elliot, T.; Gade, A.; Galaviz, D.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A.M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

    2011-01-01

    Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nuclides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

  7. Forced convection boiling of sodium. Study carried out in the framework of fast neutrons reactors safety

    International Nuclear Information System (INIS)

    Charlety, Paul

    1971-01-01

    Within the framework of the safety of fast neutron reactors, this research thesis reports the study of sodium boiling in order to assess safety margins, and to predict the consequences of some accidents. The author thus addresses issues related to sodium boiling by notably focussing on boiling physics. He first defines these issues and presents the adopted approach for this research, and then describes the experimental installation. He reports the experimental study which comprised different types of tests, and presents experimental results. He reports the development of a calculation model which could report phenomena which have been experimentally noticed [fr

  8. Corrosion of K-3 glass-contact refractory in sodium-rich aluminosilicate melts

    International Nuclear Information System (INIS)

    Lu, X.D.; Gan, H.; Buechele, A.C.; Pegg, I.L.

    1999-01-01

    The corrosion of the glass-contact refractory Monofrax K-3 in two sodium-rich aluminosilicate melts has been studied at 1,208 and 1,283 C using a modified ASTM procedure with constant agitation of the melt by air bubbling. The results for the monolithic refractory indicate a fast initial stage involving phase dissolution and transformation and a later passivated stage in which the surface of the refractory has been substantially modified. The composition of the stable spinel phase in the altered layer on monolithic coupons of K-3 is almost identical to the equilibrium composition bracketed by the dissolution of powdered K-3 into under-saturated melts on the other. The temperature and melt shear viscosity were found to have significant effects on the rates of K-3 dissolution and transformation

  9. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons

    International Nuclear Information System (INIS)

    Lau, Ch.

    2000-01-01

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons

  10. Search for low lying dipole strength in the neutron rich nucleus Ne{sup 26}

    Energy Technology Data Exchange (ETDEWEB)

    Gibelin, J

    2005-11-15

    We carried out the Coulomb excitation, on a lead target, of an exotic beam of neutron-rich nucleus Ne{sup 26} at 58 MeV/n, in order to study the possible existence of a pygmy dipole resonance above the neutron emission threshold. The experiment was performed at the Riken Research Facility, in Tokyo (Japan) and included a gamma-ray detector, a charged fragment hodoscope and a neutron detector. Using the invariant mass method in the Ne{sup 25} + n decay channel, and by comparing the reaction cross section on the lead target and a light target of aluminum, we observe a sizable amount of E1 strength between the one neutron and the two neutron emission thresholds. The corresponding Ne{sup 26} angular distribution confirms its nature and we deduce its reduced dipole transition probability value of B(E1) = 0.54 {+-} 0.18 e{sup 2}fm{sup 2}. Our method also enables us to extract for the first time the decay pattern of a pygmy resonance. By detecting the decay photons from the excited states below the neutron emission threshold and by analyzing the angular distribution of the inelastically scattered Ne{sup 26} we deduce the reduced transition probability of the first 2{sup +} state, from the ground state. The value obtained of B(E2) = 87 {+-} 13 e{sup 2}fm{sup 4} being in disagreement with a previous result. (author)

  11. 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.

  12. IOP Shape coexistence in neutron-rich strontium isotopes at N = 60

    CERN Document Server

    Clément, Emmanuel

    2017-01-01

    The structure of neutron-rich $^{96,98}$ Sr nuclei was investigated by low-energy Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E2 matrix elements has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N=60, giving rise to the coexistence of a highly deformed prolate and a spherical configuration in $^{98}$ Sr with low configuration mixing.

  13. 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

  14. 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.

  15. Sodium boiling detection in LMFBRs by acoustic-neutronic cross correlation

    International Nuclear Information System (INIS)

    Wright, S.A.

    1977-01-01

    The acoustic and neutronic noise signals caused by boiling are the signals primarily considered likely to detect sodium boiling in an LMFBR. Unfortunately, these signals may have serious signal-to-noise problems due to strong background noise sources. Neutronic-acoustic cross correlation techniques are expected to provide a means of improving the signal-to-noise ratio. This technique can improve the signal-to-noise ratio because the neutronic and acoustic signals due to boiling are highly correlated near the bubble repetition frequency, while the background noise sources are expected to be uncorrelated (or at most weakly correlated). An experiment was designed to show that the neutronic and acoustic noise signals are indeed highly correlated. The experiment consisted of simulating the void and pressure effects of local sodium boiling in the core of a zero-power reactor (ARK). The analysis showed that the neutronic and acoustic noise signals caused by boiling are almost perfectly correlated in a wide frequency band about the bubble repetition frequency. The results of the experiments were generalized to full-scale reactors to compare the inherent effectiveness of the methods which use the neutronic or acoustic signals alone with a hybrid method, which cross correlates the neutronic and acoustic signals. It was concluded that over a zone of the reactor where the void coefficient is sufficiently large (approximately 85 percent the core volume), the cross correlation method can provide a more rapid detection system for a given signal-to-noise ratio. However, where the void coefficient is small, one must probably rely on the acoustic method alone

  16. 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.

  17. 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.

  18. Impact of triaxiality on the rotational structure of neutron-rich rhenium isotopes

    Directory of Open Access Journals (Sweden)

    M.W. Reed

    2016-01-01

    Full Text Available A number of 3-quasiparticle isomers have been found and characterised in the odd-mass, neutron-rich, 187Re, 189Re and 191Re nuclei, the latter being four neutrons beyond stability. The decay of the isomers populates states in the rotational bands built upon the 9/2−[514] Nilsson orbital. These bands exhibit a degree of signature splitting that increases with neutron number. This splitting taken together with measurements of the M1/E2 mixing ratios and with the changes observed in the energy of the gamma-vibrational band coupled to the 9/2−[514] state, suggests an increase in triaxiality, with γ values of 5°, 18° and 25° deduced in the framework of a particle-rotor model.

  19. Solid thermoluminescent dosemeter of sodium tetraborate and brazilian fluorite sensible to thermic neutrons

    International Nuclear Information System (INIS)

    Fratin, L.; Cruz, M.T. da

    1987-01-01

    The production of solid thermoluminescent dosemeters sensible to thermic neutrons is described. The stages of the production are described: vitrification of sodium tetraborate, mixture and cold pressing, syntherization. The obtention of a CaF 2 : natural dosemeter with NaCl which presents sensibility to gamma radiation similar to CaF 2 : natural dosemeter with Na 2 B 4 O 7 is studied. (M.A.C.) [pt

  20. 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.

  1. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process. Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Atanasov, Dinko

    2016-07-06

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton-to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium ({sup 129-131}Cd) and caesium ({sup 132,146-148}Cs) isotopes. Measurements were done at the on-line radioactive ion-beam facility ISOLDE by using the four-trap mass spectrometer ISOLTRAP. The cadmium isotopes are key nuclides for the synthesis of stable isotopes around the mass peak A = 130 in the Solar System abundance.

  2. Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

    CERN Document Server

    AUTHOR|(CDS)2085660; Litvinov, Yuri A.; Kreim, Susanne

    Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton- to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium (129−131 Cd) and caesium...

  3. Kinetic study of human hand sodium using local in vivo neutron activation analysis

    International Nuclear Information System (INIS)

    Cohen Boulakia, Francine.

    1978-01-01

    Using local 'in vivo' activation analysis, turnover of human hand sodium is studied in 14 subjects, 7 controls and 7 decalcified osteoporotics patients. The hand of each subject is irradiated with neutrons emitted by 52 Cf sources; the equivalent dose delivered is 8 cGy. The 24 Na activity variation is plotted as function of time and the experimental curve so obtained is fitted to two exponentials. Two compartements are identified: a rapidly exchangeable one, with a half life of 1 h; an other, with a very slow turnover, the half lifes varying from 79 h to 35 h as the calcium concentration becomes sub-normal. The ratios calcium to slowly exchangeable sodium and rapidly to slowly exchangeable sodium appear to be promising for the evaluation of bone disease [fr

  4. 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.)

  5. 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.

  6. The fast neutrons reactors, the sodium, the fuel cycle: evaluation of the knowledge, innovation potential and forecast

    International Nuclear Information System (INIS)

    Moreau, J.

    2002-01-01

    This document presents the study, the design and the construction of fast neutrons reactors, cooled with sodium. From this evaluation, it details the innovation possibilities of this sector in the sustainable development context of the nuclear energy. Chapter one presents the physical and physico-chemical properties of the sodium. Chapter two analyzes the properties of the fast cores and the sodium advantages. Chapter three analyzes the great contribution of the EFR project. Chapter four takes stock on the innovation possibilities. And before the conclusion, chapter five shows that the fast neutrons reactors allow the electric power production in agreement with a sustainable development. (A.L.B.)

  7. Odd-even parity splittings and octupole correlations in neutron-rich Ba isotopes

    Science.gov (United States)

    Fu, Y.; Wang, H.; Wang, L.-J.; Yao, J. M.

    2018-02-01

    The odd-even parity splittings in low-lying parity-doublet states of atomic nuclei with octupole correlations have usually been interpreted as rotational excitations on top of octupole vibration in the language of collective models. In this paper, we report a deep analysis of the odd-even parity splittings in the parity-doublet states of neutron-rich Ba isotopes around neutron number N =88 within a full microscopic framework of beyond-mean-field multireference covariant energy density functional theory. The dynamical correlations related to symmetry restoration and quadrupole-octupole shape fluctuation are taken into account with a generator coordinate method combined with parity, particle-number, and angular-momentum projections. We show that the behavior of odd-even parity splittings is governed by the interplay of rotation, quantum tunneling, and shape evolution. Similar to 224Ra, a picture of rotation-induced octupole shape stabilization in the positive-parity states is exhibited in the neutron-rich Ba isotopes.

  8. 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...

  9. Light neutron-rich hypernuclei from the importance-truncated no-core shell model

    Science.gov (United States)

    Wirth, Roland; Roth, Robert

    2018-04-01

    We explore the systematics of ground-state and excitation energies in singly-strange hypernuclei throughout the helium and lithium isotopic chains - from He5Λ to He11Λ and from Li7Λ to Li12Λ - in the ab initio no-core shell model with importance truncation. All calculations are based on two- and three-baryon interaction from chiral effective field theory and we employ a similarity renormalization group transformation consistently up to the three-baryon level to improve the model-space convergence. While the absolute energies of hypernuclear states show a systematic variation with the regulator cutoff of the hyperon-nucleon interaction, the resulting neutron separation energies are very stable and in good agreement with available data for both nucleonic parents and their daughter hypernuclei. We provide predictions for the neutron separation energies and the spectra of neutron-rich hypernuclei that have not yet been observed experimentally. Furthermore, we find that the neutron drip lines in the helium and lithium isotopic chains are not changed by the addition of a hyperon.

  10. Crystal structure of modular sodium-rich and low-iron eudialyte from Lovozero alkaline massif

    Energy Technology Data Exchange (ETDEWEB)

    Rozenberg, K. A.; Rastsvetaeva, R. K., E-mail: rast@ns.crys.ras.ru; Aksenov, S. M. [Federal Scientific Research Center “Crystallography and Photonics”, Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2016-09-15

    The structure of the sodium-rich representative of the eudialyte group found by A.P. Khomyakov at the Lovozero massif (Kola Peninsula) is studied by X-ray diffraction. The trigonal cell parameters are: a = 14.2032(1) and c = 60.612(1) Å, V = 10589.13 Å3, space group R3m. The structure is refined to the final R = 5.0% in the anisotropic approximation of atomic displacement parameters using 3742|F| > 3σ(F). The idealized formula (Z = 3) is Na{sub 37}Ca{sub 10}Mn{sub 2}FeZr{sub 6}Si{sub 50}(Ti, Nb){sub 2}O{sub 144}(OH){sub 5}Cl{sub 3} · H{sub 2}O. Like other 24-layer minerals of the eudialyte group, this mineral has a modular structure. Its structure contains two modules, namely, “alluaivite” (with an admixture of “eudialyte”) and “kentbrooksite,” called according to the main structural fragments of alluaivite, eudialyte, and kentbrooksite. The mineral found at the Lovozero alkaline massif shows some chemical and symmetry-structural distinctions from the close-in-composition labyrinthite modular mineral from the Khibiny massif. The difference between the minerals stems from different geochemical conditions of mineral formation in the two regions.

  11. Neutrino-'pasta' scattering: The opacity of nonuniform neutron-rich matter

    International Nuclear Information System (INIS)

    Horowitz, C.J.; Perez-Garcia, M.A.; Piekarewicz, J.

    2004-01-01

    Neutron-rich matter at subnuclear densities may involve complex structures displaying a variety of shapes, such as spherical, slablike, and/or rodlike shapes. These phases of the nuclear pasta are expected to exist in the crust of neutron stars and in core-collapse supernovae. The dynamics of core-collapse supernovae is very sensitive to the interactions between neutrinos and nucleons/nuclei. Indeed, neutrino excitation of the low-energy modes of the pasta may allow for a significant energy transfer to the nuclear medium, thereby reviving the stalled supernovae shock. The linear response of the nuclear pasta to neutrinos is modeled via a simple semiclassical simulation. The transport mean free path for μ and τ neutrinos (and antineutrinos) is expressed in terms of the static structure factor of the pasta, which is evaluated using Metropolis Monte Carlo simulations

  12. Evidence for a smooth onset of deformation in the neutron-rich Kr isotopes

    CERN Document Server

    Albers, M; Nomura, K; Blazhev, A; Jolie, J; Mucher, D; Bastin, B; Bauer, C; Bernards, C; Bettermann, L; Bildstein, V; Butterworth, J; Cappellazzo, M; Cederkall, J; Cline, D; Darby, I; Das Gupta, S; Daugas, J M; Davinson, T; De Witte, H; Diriken, J; Filipescu, D; Fiori, E; Fransen, C; Gaffney, L P; Georgiev, G; Gernhauser, R; Hackstein, M; Heinze, S; Hess, H; Huyse, M; Jenkins, D; Konki, J; Kowalczyk, M; Kroll, T; Krucken, R; Litzinger, J; Lutter, R; Marginean, N; Mihai, C; Moschner, K; Napiorkowski, P; Nara Singh, B S; Nowak, K; Otsuka, T; Pakarinen, J; Pfeiffer, M; Radeck, D; Reiter, P; Rigby, S; Robledo, L M; Rodriguez-Guzman, R; Rudigier, M; Sarriguren, P; Scheck, M; Seidlitz, M; Siebeck, B; Simpson, G; Thole, P; Thomas, T; Van de Walle, J; Van Duppen, P; Vermeulen, M; Voulot, D; Wadsworth, R; Wenander, F; Wimmer, K; Zell, K O; Zielinska, M

    2012-01-01

    The neutron-rich nuclei $^{94,96}$Kr were studied via projectile Coulomb excitation at the REX-ISOLDE facility at CERN. Level energies of the first excited 2$^{+}$ states and their absolute $E2$ transition strengths to the ground state are determined and discussed in the context of the $E(2^{+}_{1})$ and $B(E2;2^{+}_{1} \\rightarrow 0^{+}_{1})$ systematics of the krypton chain. Contrary to previously published results no sudden onset of deformation is observed. This experimental result is supported by a new proton-neutron interacting boson model calculation based on the constrained Hartree-Fock-Bogoliubov approach using the microscopic Gogny-D1M energy density functional.

  13. High spin study and lifetime measurements of neutron rich Co isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Regan, P H; Arrison, J W; Huttmeier, U J; Balamuth, D P [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Physics

    1992-08-01

    The neutron rich nuclei {sup 61,63}Co have been studied using the reactions {sup 16}O({sup 48}Ca,p2n){sup 61}Co at 110 MeV and {sup 18}O({sup 48}Ca,p2n){sup 63}Co at 110 MeV respectively. Discrete lines from the channels of interest were investigated using pre-scaled {gamma} singles, charged-particle-{gamma}, neutron-charged-particle-{gamma} and charged particle-{gamma}-{gamma} data. Decay schemes, with level spins deduced from angular distribution data are presented together with preliminary information on the lifetimes of some higher excitation states. These data represent the first study on the medium to high spin states in these nuclei. (author). 9 refs., 1 tab., 4 figs.

  14. $\\beta$-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.

  15. 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.)

  16. 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

  17. 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

  18. 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)

  19. Application of the generator coordinate method to neutron-rich Se and Ge isotopes

    Directory of Open Access Journals (Sweden)

    Higashiyama Koji

    2014-03-01

    Full Text Available The quantum-number projected generator coordinate method (GCM is applied to the neutron-rich Se and Ge isotopes, where the monopole and quadrupole pairing plus quadrupole-quadrupole interaction is employed as an effective interaction. The energy spectra obtained by the GCM are compared to both the shell model results and the experimental data. The GCM reproduces well the energy levels of high-spin states as well as the low-lying states. The structure of the low-lying collective states is analyzed through the GCM wave functions.

  20. Decay of a three-quasiparticle isomer in the neutron-rich nucleus 183Ta

    Directory of Open Access Journals (Sweden)

    Zhu S.

    2012-10-01

    Full Text Available Excited states in neutron-rich tantalum isotopes have been studied with deep-inelastic reactions using 136Xe ions incident on a 186W target. New transitions observed below the τ=1.3 μs isomer in 183Ta have enabled the establishment of its energy and put limits on the spin and parity. On the basis of the reduced hindrances for the depopulating transitions, a 3-quasiparticle configuration of ν1/2−[510]11/2+[615] ⊗ π9/2−[514] is suggested.

  1. 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)

  2. 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

  3. Coulomb excitation of neutron-rich $^{134-136}$Sn isotopes

    CERN Multimedia

    We propose to study excited states in the isotopes $^{134,136}$Sn by $\\gamma$-ray spectroscopy following "safe" Coulomb excitation. The experiment aims to investigate the evolution of quadrupole collectivity beyond the magic shell closure at N = 82 by the determination of B(E2) values and electric quadrupole moments $\\mathcal{Q}_2$. Recent shell-model calculations using realistic interactions predict possible enhanced collectivity in neutron-rich regions. Evidence for this could be obtained by this experiment. Furthermore, the currently unknown excitation energies of the 2$^+_{1}$ and 4$^+_{1}$ states in $^{136}$Sn will be measured for the first time.

  4. The CARDS array for neutron-rich decay spectroscopy at HRIBF

    CERN Document Server

    Batchelder, J C; Bingham, C R; Carter, H K; Cole, J D; Fong, D; Garrett, P E; Grzywacz, R; Hamilton, J H; Hartley, D J; Hwang, J K; Krolas, W; Kulp, D C; Larochelle, Y; Piechaczek, A; Ramayya, A V; Rykaczewski, K; Spejewski, E H; Stracener, D W; Tantawy, M N; Winger, J A; Wood, J; Zganjar, E F

    2003-01-01

    An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (approx 1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection.

  5. The CARDS array for neutron-rich decay spectroscopy at HRIBF

    International Nuclear Information System (INIS)

    Batchelder, J.C.; Bilheux, J.-C.; Bingham, C.R.; Carter, H.K.; Cole, J.D.; Fong, D.; Garrett, P.E.; Grzywacz, R.; Hamilton, J.H.; Hartley, D.J.; Hwang, J.K.; Krolas, W.; Kulp, D.; Larochelle, Y.; Piechaczek, A.; Ramayya, A.V.; Rykaczewski, K.P.; Spejewski, E.H.; Stracener, D.W.; Tantawy, M.N.; Winger, J.A.; Wood, J.; Zganjar, E.F.

    2003-01-01

    An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (∼1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection

  6. Developments and application of neutron noise diagnostics of sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Zylbersztejn, F.

    2013-01-01

    The Sodium cooled Fast Reactor (SFR) is one of the six reactor types selected by the Generation-IV international forum (GIF), and the building of an industrial prototype is planned in France. The safety standard of the future SFR has to be equivalent to the EPR's. The general improvement of the safety of the new reactor goes through the examination of all the potentially harmful scenarios and both the study and monitoring of early signs. The mechanical deformations of the core can have harmful consequences in sodium fast reactors, such as unexpected power variations due to the reactivity increase in case of core compaction, or the excessive deterioration of the mechanical structures. The monitoring of such phenomena and of their potential early signs is then needed. The monitoring of such phenomena can be done with neutron detectors placed inside and outside the tank. This PhD thesis deals with the study of the neutron noise generated by the periodic deformation of the SFR core, restricted to the so-called core compaction or core flowering phenomenon, a deformation consisting in the variation of the inter-assembly sodium width by a radial bending the assemblies (the assemblies in SFR are held by the base). The PhD thesis has been performed within collaboration between CEA (France) and Chalmers Institute of Technology (Sweden). The work realized during the thesis led to the publication of 3 articles as first author and another as second author. This work has embraced the following topics: A state of the art of the monitoring of the core deformation phenomenon by interpretation of the noise measurements in SFR has been done. The PHENIX reactor multi physics measurements database has been scrutinized to provide an interpretation of the neutron noise bringing out mechanical vibration phenomena. An important conclusion was that the lack of theoretical knowledge about the neutron noise induced by the vibration phenomenon and the ill positioning of the neutron detectors

  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. Feasibility of calibration of liquid sodium flowmeters by neutron activation techniques

    International Nuclear Information System (INIS)

    Kehler, P.

    1976-07-01

    Velocities of fluids in pipes can be measured by injecting radioactive tracers into the fluid and recording the activity downstream of the injection point. One convenient method of injecting radioactive tracers is by neutron activation of the fluid itself. The present report describes a FORTRAN program that can be used for the prediction of the counting rates of fluid flow tests performed with a pulsed neutron source and a scintillation detector. The program models the flow profile and the mixing of the fluid, the attenuation of neutrons and gamma rays in the fluid, and the geometric arrangement of the source and the detector. Using this program, an experiment for the measurement of the secondary sodium flow of the EBR-II was optimized. A pulsed D,T neutron source and a 5 in. x 5 in. NaI detector will be used in the EBR-II test. Under optimized conditions, the expected accuracy of the flow measurement is about 2 percent

  9. 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.

  10. Study of shape transition in the neutron-rich Os isotopes

    Directory of Open Access Journals (Sweden)

    John P.R.

    2014-03-01

    Full Text Available The neutron-rich isotopes of tungsten, osmium and platinum have different shapes in their ground states and present also shape transitions phenomena. Spectroscopic information for these nuclei is scarce and often limited to the gamma rays from the decay of isomeric states. For the neutron-rich even-even osmium isotopes 194Os and 198Os, a shape transition between a slightly prolate deformed to an oblate deformed ground state was deduced from the observed level schemes. For the even-even nucleus lying in between, 196Os, no gamma ray transition is known. In order to elucidate the shape transition and to test the nuclear models describing it, this region was investigated through gamma-ray spectroscopy using the AGATA demonstrator and the large acceptance heavy-ion spectrometer PRISMA at LNL, Italy. A two-nucleon transfer from a 198Pt target to a stable 82Se beam was utilized to populate medium-high spin states of 196Os. The analysis method and preliminary results, including the first life-time measurement of isomeric states with AGATA, are presented.

  11. Development of axial asymmetry in the neutron-rich nucleus {sup 110}Mo

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H., E-mail: hiroshi@ribf.riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamaguchi, K.; Odahara, A. [Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka (Japan); Sumikama, T. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Nishimura, S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yoshinaga, K. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Li, Z. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Miyashita, Y. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Sato, K. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Prochniak, L. [Institute of Physics, Maria Curie-Sklodowska University, pl. M. Curie-Sklodowskiej 1, 20-031 Lublin (Poland); Baba, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Berryman, J.S. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Blasi, N. [INFN, Sezione di Milano, via Celoria 16, I-20133 Milano (Italy); Bracco, A.; Camera, F. [INFN, Sezione di Milano, via Celoria 16, I-20133 Milano (Italy); Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Chiba, J. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Doornenbal, P. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Go, S.; Hashimoto, T.; Hayakawa, S. [Center for Nuclear Study, University of Tokyo, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan)

    2011-10-19

    The neutron-rich nucleus {sup 110}Mo has been investigated by means of {gamma}-ray spectroscopy following the {beta}-decay of {sup 110}Nb, produced using in-flight fission of a {sup 238}U beam at 345 MeV/nucleon at the RIBF facility. In addition to the ground-band members reported previously, spectroscopic information on the low-lying levels of the quasi-{gamma} band built on the second 2{sup +} state at 494 keV has been obtained for the first time. The experimental finding of the second 2{sup +} state being lower than the yrast 4{sup +} level suggests that axially-asymmetric {gamma} softness is substantially enhanced in this nucleus. The experimental results are compared with model calculations based on the general Bohr Hamiltonian method. The systematics of the low-lying levels in even-even A{approx}110 nuclei is discussed in comparison with that in the neutron-rich A{approx}190 region, by introducing the quantity E{sub S}/E(2{sub 1}{sup +}), E{sub S}=E(2{sub 2}{sup +})-E(4{sub 1}{sup +}), as a global signature of the structural evolution involving axial asymmetry.

  12. New neutron-rich isotope production in 154Sm+160Gd

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2016-09-01

    Full Text Available Deep inelastic scattering in 154Sm+160Gd at energies above the Bass barrier is for the first time investigated with two different microscopic dynamics approaches: improved quantum molecular dynamics (ImQMD model and time dependent Hartree–Fock (TDHF theory. No fusion is observed from both models. The capture pocket disappears for this reaction due to strong Coulomb repulsion and the contact time of the di-nuclear system formed in head-on collisions is about 700 fm/c at an incident energy of 440 MeV. The isotope distribution of fragments in the deep inelastic scattering process is predicted with the simulations of the latest ImQMD-v2.2 model together with a statistical code (GEMINI for describing the secondary decay of fragments. More than 40 extremely neutron-rich unmeasured nuclei with 58≤Z≤76 are observed and the production cross sections are at the order of μb to mb. The multi-nucleon transfer reaction of Sm+Gd could be an alternative way to synthesize new neutron-rich lanthanides which are difficult to be produced with traditional fusion reactions or fission of actinides.

  13. 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.

  14. 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.

  15. Experimental study of the lifetime and phase transition in neutron-rich Zr 98 ,100 ,102

    Science.gov (United States)

    Ansari, S.; Régis, J.-M.; Jolie, J.; Saed-Samii, N.; Warr, N.; Korten, W.; Zielińska, M.; Salsac, M.-D.; Blanc, A.; Jentschel, M.; Köster, U.; Mutti, P.; Soldner, T.; Simpson, G. S.; Drouet, F.; Vancraeyenest, A.; de France, G.; Clément, E.; Stezowski, O.; Ur, C. A.; Urban, W.; Regan, P. H.; Podolyák, Zs.; Larijani, C.; Townsley, C.; Carroll, R.; Wilson, E.; Mach, H.; Fraile, L. M.; Paziy, V.; Olaizola, B.; Vedia, V.; Bruce, A. M.; Roberts, O. J.; Smith, J. F.; Scheck, M.; Kröll, T.; Hartig, A.-L.; Ignatov, A.; Ilieva, S.; Lalkovski, S.; Mǎrginean, N.; Otsuka, T.; Shimizu, N.; Togashi, T.; Tsunoda, Y.

    2017-11-01

    Rapid shape changes are observed for neutron-rich nuclei with A around 100. In particular, a sudden onset of ground-state deformation is observed in the Zr and Sr isotopic chains at N = 60: Low-lying states in N ≤58 nuclei are nearly spherical, while those with N ≥60 have a rotational character. Nuclear lifetimes as short as a few picoseconds can be measured using fast-timing techniques with LaBr3(Ce) scintillators, yielding a key ingredient in the systematic study of the shape evolution in this region. We used neutron-induced fission of 241Pu and 235U to study lifetimes of excited states in fission fragments in the A ˜100 region with the EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin. In particular, we applied the generalized centroid difference method to deduce lifetimes of low-lying states for the nuclei 98Zr (N = 58), 100Zr, and 102Zr (N ≥60 ). The results are discussed in the context of the presumed phase transition in the Zr chain by comparing the experimental transition strengths with the theoretical calculations using the interacting boson model and the Monte Carlo shell model.

  16. Neutron-rich polonium isotopes studied with in-source laser spectroscopy

    CERN Document Server

    Dexters, Wim; Cocolios, T E

    This work studies the unknown region of neutron rich polonium isotopes. The polonium isotopes, with Z=84, lie above the magic lead nuclei (Z=82). The motivation for this research can mainly be found in these lead nuclei. When looking at the changes in the mean square charge radii beyond the N=126 shell gap, a kink is observed. This kink is also found in the radon (Z=86) and radium (Z=88) isotopes. The observed effect cannot be reproduced with our current models. The polonium isotopes yield more information on the kink and they are also able to link the known charge radii in lead isotopes to those in radon and radium. Additionally, the nuclear moments of the odd-neutron isotope $^{211}$Po are investigated. This nucleus has two protons and one neutron more than the doubly magic nucleus $^{208}$Pb. Nuclear moments of isotopes close to this doubly magic nucleus are good tests for the theoretic models. Besides pushing the models to their limits, the nuclear moments of $^{211}$Po also yield new information on the f...

  17. Equation of state of neutron-rich nuclear matter from chiral effective field theory

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Norbert; Strohmeier, Susanne [Technische Universitaet Muenchen (Germany)

    2016-07-01

    Based on chiral effective field theory, the equation of state of neutron-rich nuclear matter is investigated systematically. The contributing diagrams include one- and two-pion exchange together with three-body terms arising from virtual Δ(1232)-isobar excitations. The proper expansion of the energy per particle, anti E(k{sub f},δ) = anti E{sub n}(k{sub f}) + δB{sub 1}(k{sub f}) + δ{sup 5/3}B{sub 5/3}(k{sub f}) + δ{sup 2}B{sub 2}(k{sub f}) +.., for the system with neutron density ρ{sub n} = k{sub f}{sup 3}(1-δ)/3π{sup 2} and proton density ρ{sub p} = k{sub f}{sup 3}δ/3π{sup 2} is performed analytically for the various interaction contributions. One observes essential structural differences to the commonly used quadratic approximation. The density dependent coefficient B{sub 1}(k{sub f}) turns out to be unrelated to the isospin-asymmetry of nuclear matter. The coefficient B{sub 5/3}(k{sub f}) of the non-analytical δ{sup 5/3}-term receives contributions from the proton kinetic energy and from the one- and two-pion exchange interactions. The physical consequences for neutron star matter are studied.

  18. Optimal timing of neutron irradiation for boron neutron capture therapy after intravenous infusion of sodium borocaptate in patients with glioblastoma

    International Nuclear Information System (INIS)

    Kageji, Teruyoshi; Nagahiro, Shinji; Kitamura, Katsushi; Nakagawa, Yoshinobu; Hatanaka, Hiroshi; Haritz, Dietrich; Grochulla, Frank; Haselsberger, Klaus; Gabel, Detlef

    2001-01-01

    Purpose: A cooperative study in Europe and Japan was conducted to determine the pharmacokinetics and boron uptake of sodium borocaptate (BSH: Na 2 B 12 H 11 SH), which has been introduced clinically as a boron carrier for boron neutron capture therapy in patients with glioblastoma. Methods and Materials: Data from 56 patients with glioblastoma who received BSH intravenous infusion were retrospectively reviewed. The pharmacokinetics were evaluated in 50 patients, and boron uptake was investigated in 47 patients. Patients received BSH doses between 12 and 100 mg/kg of body weight. For the evaluation, the infused boron dose was scaled linearly to 100 mg/kg BSH. Results: In BSH pharmacokinetics, the average value for total body clearance, distribution volume of steady state, and mean residence time was 3.6±1.5 L/h, 223.3±160.7 L, and 68.0±52.5 h, respectively. The average values of the boron concentration in tumor adjusted to 100 mg/kg BSH, the boron concentration in blood adjusted to 100 mg/kg BSH, and the tumor/blood boron concentration ratio were 37.1±35.8 ppm, 35.2±41.8 ppm, and 1.53±1.43, respectively. A good correlation was found between the logarithmic value of T adj and the interval from BSH infusion to tumor tissue sampling. About 12-19 h after infusion, the actual values for T adj and tumor/blood boron concentration ratio were 46.2±36.0 ppm and 1.70±1.06, respectively. The dose ratio between tumor and healthy tissue peaked in the same interval. Conclusion: For boron neutron capture therapy using BSH administered by intravenous infusion, this work confirms that neutron irradiation is optimal around 12-19 h after the infusion is started

  19. Metabolic activity of sodium, measured by neutron activation, in the hands of patients suffering from bone diseases: concise communication

    International Nuclear Information System (INIS)

    Spinks, T.J.; Bewley, D.K.; Paolillo, M.; Vlotides, J.; Joplin, G.F.; Ranicar, A.S.O.

    1980-01-01

    Turnover of sodium in the human hand was studied by neutron activation. Patients suffering from various metabolic abnormalities affecting the skeleton, who were undergoing routine neutron activation for the measurement of calcium, were investigated along with a group of healthy volunteers. Neutron activation labels the sodium atoms simultaneously and with equal probability regardless of the turnover time of individual body compartments. The loss of sodium can be described either by a sum of two exponentials or by a single power function. Distinctions between patients and normal subjects were not apparent from the exponential model but were brought out by the power function. The exponent of time in the latter is a measure of clearance rate. The mean values of this parameter in (a) a group of patients suffering from acromegaly; (b) a group including Paget's disease, osteoporosis, Cushing's disease, and hyperparathyroidism; and (c) a group of healthy subjects, were found to be significantly different from each other

  20. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Verma, V., E-mail: vasudha.verma@physics.uu.se [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Barbot, L.; Filliatre, P. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Hellesen, C. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Jammes, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Svärd, S. Jacobsson [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2017-07-11

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment. - Highlights: • Studied possibility of using SPNDs as in-core detectors in SFRs. • Study done to detect local power profile changes when reactor is at nominal power. • SPND with a Pt-emitter gives measurable prompt current of the order of 600 nA/m. • Dominant proportion of prompt response is maintained throughout the operation. • Detector signal gives dynamic information on the power fluctuations.

  1. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Science.gov (United States)

    Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

    2017-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

  2. Calculation of the neutron noise induced by periodic deformations of a large sodium-cooled fast reactor core

    International Nuclear Information System (INIS)

    Zylbersztejn, F.; Tran, H.N.; Pazsit, I.; Filliatre, P.; Jammes, C.

    2014-01-01

    The subject of this paper is the calculation of the neutron noise induced by small-amplitude stationary radial variations of the core size (core expansion/compaction, also called core flowering) of a large sodium-cooled fast reactor. The calculations were performed on a realistic model of the European Sodium Fast Reactor (ESFR) core with a thermal output of 3600 MW(thermal), using a multigroup neutron noise simulator. The multigroup cross sections and their fluctuations that represent the core geometry changes for the neutron noise calculations were generated by the code ERANOS. The space and energy dependences of the noise source represented by the core expansion/compaction and the induced neutron noise are calculated and discussed. (authors)

  3. 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.)

  4. Decay Study for the very Neutron-Rich Sn Nuclides, $^{135-140}$Sn Separated by Selective Laser Ionization

    CERN Multimedia

    2002-01-01

    %IS378 %title\\\\ \\\\ In this investigation, we wish to take advantage of chemically selective laser ionization to separate the very-neutron-rich Sn nuclides and determine their half-lives and delayed-neutron branches (P$_{n}$) using the Mainz $^{3}$He-delayed neutron spectrometer and close-geometry $\\gamma$-ray spectroscopy system. The $\\beta$-decay rates are dependent on a number of nuclear structure factors that may not be well described by models of nuclear structure developed for nuclides near stability. Determination of these decay properties will provide direct experimental data for r-process calculations and test the large number of models of nuclear structure for very-neutron rich Sn nuclides now in print.

  5. Electrochemical lithium and sodium intercalation into the tantalum-rich layered chalcogenides Ta2Se and Ta2Te3

    International Nuclear Information System (INIS)

    Lavela, P.; Tirado, J.L.

    1999-01-01

    Two-layered tantalum chalcogenides are evaluated as alkali metal intercalation hosts in lithium and sodium electrochemical cells. The metal-rich pseudo-two-dimensional solid Ta 2 Se shows a poor intercalation behaviour. Lithium reacts with the selenide by deintercalating selenium from the blocks of Ta-related b.c.c. structure leading to a collapse of the structure and the formation of tantalum metal. Sodium is reversibly intercalated to a limited extent leading to complex structural changes in the selenide, as revealed by electron diffraction. The two-dimensional telluride Ta 2 Te 3 allows a topotactic intercalation of lithium below 1 F/mol, while a more extended reaction leads to sample amorphization. The better intercalation behaviour of this solid can be related with the one-atom thick metal layer and the van der Waals gap separating tellurium atoms of successive layers. Sodium can be reversibly intercalated into Ta 2 Te 3 in sodium cells which show a good cycling behaviour. Exposure of the intercalated solid to water vapour allows the preparation of hydrated products with a monolayer or a bilayer of water molecules solvating sodium in the interlayer space. (orig.)

  6. Beta-decay measurements of neutron-rich thallium, lead, and bismuth by means of resonant laser ionisation

    Science.gov (United States)

    Franchoo, S.; de Witte, H.; Andreyev, A. N.; Cederka¨Ll, J.; Dean, S.; de Smet, A.; Eeckhaudt, S.; Fedorov, D. V.; Fedosseev, V. N.; G´Rska, M.; Huber, G.; Huyse, M.; Janas, Z.; Ko¨Ster, U.; Kurcewicz, W.; Kurpeta, J.; Mayer, P.; Płchocki, A.; van de Vel, K.; van Duppen, P.; Weissman, L.; Isolde Collaboration

    2004-04-01

    Neutron-rich thallium, lead, and bismuth isotopes were investigated at the ISOLDE facility. After mass separation and resonant laser ionisation of the produced activity, new spectroscopic data were obtained for 215,218Bi and 215Pb. An attempt to reach heavy thallium had to be abandoned because of a strong francium component in the beam that gave rise to a neutron background through (α,n) reactions on the aluminium walls of the experimental chamber.

  7. Sodium

    Science.gov (United States)

    Table salt is a combination of two minerals - sodium and chloride Your body needs some sodium to work properly. It helps with the function ... in your body. Your kidneys control how much sodium is in your body. If you have too ...

  8. Fertile assembly for a fast neutron nuclear reactor cooled by liquid sodium, with regulation of the cooling rate

    International Nuclear Information System (INIS)

    Pradal, L.; Berte, M.; Chiarelli, C.

    1985-01-01

    The assembly has a casing in which are arranged the fertile elements, the liquid sodium flowing through the casing along these elements. It includes several apertured diaphragms transverse to the rods to regulate the liquid sodium flow rate. At least one diaphragm, in its central part around its aperture, of a material soluble in liquid sodium, such as copper. The invention applies, more particularly, to fast neutron nuclear reactor having a heterogeneous core. The coolant flow can increase with time to match the increased power generated by the fertile assembly along its life [fr

  9. Recent activities for β-decay half-lives and β-delayed neutron emission of very neutron-rich isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dillmann, Iris [TRIUMF, Vancouver BC, V6T 2A3, Canada and GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Abriola, Daniel [Laboratorio Tandar, Comisión Nacional de Energía Atómica, B1650KINA, San Martín, Buenos Aires (Argentina); Singh, Balraj [Department of Physics and Astronomy, McMaster University, Hamilton ON, L8S 4M1 (Canada)

    2014-05-02

    Beta-delayed neutron (βn) emitters play an important, two-fold role in the stellar nucleosynthesis of heavy elements in the 'rapid neutron-capture process' (r process). On one hand they lead to a detour of the material β-decaying back to stability. On the other hand, the released neutrons increase the neutron-to-seed ratio, and are re-captured during the freeze-out phase and thus influence the final solar r-abundance curve. A large fraction of the isotopes inside the r-process reaction path are not yet experimentally accessible and are located in the (experimental) 'Terra Incognita'. With the next generation of fragmentation and ISOL facilities presently being built or already in operation, one of the main motivation of all projects is the investigation of these very neutron-rich isotopes. A short overview of one of the planned programs to measure βn-emitters at the limits of the presently know isotopes, the BRIKEN campaign (Beta delayed neutron emission measurements at RIKEN) will be given. Presently, about 600 β-delayed one-neutron emitters are accessible, but only for a third of them experimental data are available. Reaching more neutron-rich isotopes means also that multiple neutron-emission becomes the dominant decay mechanism. About 460 β-delayed two-, three-or four-neutron emitters are identified up to now but for only 30 of them experimental data about the neutron branching ratios are available, most of them in the light mass region below A=30. The International Atomic and Energy Agency (IAEA) has identified the urgency and picked up this topic recently in a 'Coordinated Research Project' on a 'Reference Database for Beta-Delayed Neutron Emission Data'. This project will review, compile, and evaluate the existing data for neutron-branching ratios and half-lives of β-delayed neutron emitters and help to ensure a reliable database for the future discoveries of new isotopes and help to constrain astrophysical and

  10. 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.

  11. 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

  12. Mass measurements of neutron-rich indium isotopes toward the N =82 shell closure

    Science.gov (United States)

    Babcock, C.; Klawitter, R.; Leistenschneider, E.; Lascar, D.; Barquest, B. R.; Finlay, A.; Foster, M.; Gallant, A. T.; Hunt, P.; Kootte, B.; Lan, Y.; Paul, S. F.; Phan, M. L.; Reiter, M. P.; Schultz, B.; Short, D.; Andreoiu, C.; Brodeur, M.; Dillmann, I.; Gwinner, G.; Kwiatkowski, A. A.; Leach, K. G.; Dilling, J.

    2018-02-01

    Precise mass measurements of the neutron-rich In-130125 isotopes have been performed with the TITAN Penning trap mass spectrometer. TITAN's electron beam ion trap was used to charge breed the ions to charge state q =13 + thus providing the necessary resolving power to measure not only the ground states but also isomeric states at each mass number. In this paper, the properties of the ground states are investigated through a series of mass differentials, highlighting trends in the indium isotopic chain as compared to its proton-magic neighbor, tin (Z =50 ). In addition, the energies of the indium isomers are presented. The (8-) level in 128In is found to be 78 keV lower than previously thought and the (21 /2- ) isomer in 127In is shown to be lower than the literature value by more than 150 keV.

  13. 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.

  14. Observation of isoscalar and isovector dipole excitations in neutron-rich 20O

    Directory of Open Access Journals (Sweden)

    N. Nakatsuka

    2017-05-01

    Full Text Available The isospin characters of low-energy dipole excitations in neutron-rich unstable nucleus 20O were investigated, for the first time in unstable nuclei. Two spectra obtained from a dominant isovector probe (O20+Au and a dominant isoscalar probe (O20+α were compared and analyzed by the distorted-wave Born approximation to extract independently the isovector and isoscalar dipole strengths. Two known 1− states with large isovector dipole strengths at energies of 5.36(5 MeV (11− and 6.84(7 MeV (12− were also excited by the isoscalar probe. These two states were found to have different isoscalar dipole strengths, 2.70(32% (11− and 0.67(12% (12−, respectively, in exhaustion of the isoscalar dipole-energy-weighted sum rule. The difference in isoscalar strength indicated that they have different underlying structures.

  15. Quadrupole collectivity beyond N = 50 in neutron- rich Se and Kr isotopes

    Science.gov (United States)

    Elman, Brandon; Gade, A.; Barofsky, D.; Bender, P. C.; Bowry, M.; Hjorth-Jensen, M.; Kemper, K. W.; Lipschutz, S.; Lunderberg, E.; Sachmpazidi, N.; Terpstra, N.; Walters, W. B.; Weisshaar, D.; Westerberg, A.; Williams, S. J.; Wimmer, K.

    2017-09-01

    We will present results on measuring the B (E 2 ;01+ ->2n+) strength for the neutron-rich 88,90Kr and 86Se isotopes from intermediate-energy Coulomb excitation. The electric quadrupole transition strengths to the first 2+ state complete, with considerably improved uncertainties, the evolution of quadrupole collectivity in the Kr and Se isotopes approaching N = 60 , for which 90Kr and 86Se had previously been the most uncertain. We also report significant excitation strength to several higher lying 2+ states in the krypton isotopes. The results confirm shell model calculations in the π (fpg) - ν (sdg) shell with only a minimally tuned shell model setup that is based on a nucleon-nucleon interaction derived from effective field theory with effective charges adjusted to 86Kr.

  16. Excited-state lifetimes in neutron-rich Ce isotopes from EXILL and FATIMA

    Energy Technology Data Exchange (ETDEWEB)

    Koseoglou, P.; Pietralla, N.; Stoyanka, I.; Kroell, T. [IKP, TU-Darmstadt, Darmstadt (Germany); Werner, V. [IKP, TU-Darmstadt, Darmstadt (Germany); Yale University (United States); Bernards, C.; Cooper, N. [Yale University (United States); Blanc, A.; Jentschel, M.; Koester, U.; Mutti, P.; Soldner, T.; Urban, W. [ILL Grenoble (France); Bruce, A.M.; Roberts, O.J. [University of Brighton (United Kingdom); Cakirli, R.B. [MPIK Heidelberg (Germany); France, G. de [GANIL Caen (France); Humby, P.; Patel, Z.; Podolyak, Zs.; Regan, P.H.; Wilson, E. [University of Surrey (United Kingdom); Jolie, J.; Regis, J.-M.; Saed-Samii, N.; Wilmsen, D. [KP, University of Cologne (Germany); Paziy, V. [Universidad Complutense (Spain); Simpson, G.S. [PSC Grenoble (France); Ur, C.A. [INFN Legnaro (Italy)

    2016-07-01

    {sup 235}U and {sup 241}Pu fission fragments were measured by a mixed spectrometer consisting of high-resolution Ge and fast LaBr{sub 3}(Ce)-scintillator detectors at the high-flux reactor of the ILL. Prompt γ-ray cascades from the nuclei of interest are selected via Ge-Ge-LaBr{sub 3}-LaBr{sub 3} coincidences. The good energy resolution of the Ge allow precise gates to be set, selecting the cascade, hence, the nucleus of interest. The excellent timing performance of the LaBr{sub 3} detectors in combination with the General Centroid Difference method allows the measurement of lifetimes in the ps range in preparation for the FATIMA experiment at FAIR. The first results on neutron-rich Ce isotopes are presented.

  17. 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)

  18. Microscopic multiphonon approach to spectroscopy in the neutron-rich oxygen region

    Science.gov (United States)

    De Gregorio, G.; Knapp, F.; Lo Iudice, N.; Veselý, P.

    2018-03-01

    Background: A fairly rich amount of experimental spectroscopic data have disclosed intriguing properties of the nuclei in the region of neutron rich oxygen isotopes up to the neutron dripline. They, therefore, represent a unique laboratory for studying the evolution of nuclear structure away from the stability line. Purpose: We intend to give an exhaustive microscopic description of low and high energy spectra, dipole response, weak, and electromagnetic properties of the even 22O and the odd 23O and 23F. Method: An equation of motion phonon method generates an orthonormal basis of correlated n -phonon states (n =0 ,1 ,2 ,⋯ ) built of constituent Tamm-Dancoff phonons. This basis is adopted to solve the full eigenvalue equations in even nuclei and to construct an orthonormal particle-core basis for the eigenvalue problem in odd nuclei. No approximations are involved and the Pauli principle is taken into full account. The method is adopted to perform self-consistent, parameter free, calculations using an optimized chiral nucleon-nucleon interaction in a space encompassing up to two-phonon basis states. Results: The computed spectra in 22O and 23O and the dipole cross section in 22O are in overall agreement with the experimental data. The calculation describes poorly the spectrum of 23F. Conclusions: The two-phonon configurations play a crucial role in the description of spectra and transitions. The large discrepancies concerning the spectra of 23F are ultimately traced back to the large separation between the Hartree-Fock levels belonging to different major shells. We suggest that a more compact single particle spectrum is needed and can be generated by a new chiral potential which includes explicitly the contribution of the three-body forces.

  19. Decay studies and mass measurements on isobarically pure neutron-rich Hg and Tl isotopes

    CERN Multimedia

    Schweikhard, L C; Savreux, R P; Hager, U D K; Beck, D; Blaum, K

    2007-01-01

    We propose to perform mass measurements followed by $\\beta$- and $\\gamma$-decay studies on isobarically pure beams of neutron-rich Hg and Tl isotopes, which are very poorly known due to a large contamination at ISOL-facilities with surface-ionised francium. The aim is to study the binding energies of mother Hg and Tl nuclides, as well as the energies, spins and parities of the excited and ground states in the daughter Tl and Pb isotopes. The proposed studies will address a new subsection of the nuclear chart, with Z 126, where only 9 nuclides have been observed so far. Our studies will provide valuable input for mass models and shell-model calculations: they will probe the proton hole-neutron interaction and will allow to refine the matrix elements for the two-body residual interaction. Furthermore, they also give prospects for discovering new isomeric states or even new isotopes, for which the half-lives are predicted in the minute- and second-range.\\\\ To reach the isobaric purity, the experiments will be p...

  20. Coulomb Excitation of a Neutron-Rich $^{88}$Kr Beam Search for Mixed Symmetry States

    CERN Multimedia

    Andreoiu, C; Napiorkowski, P J; Iwanicki, J S

    2002-01-01

    We propose to use the ISOLDE/REX/MINIBALL/CD set-up to perform a Coulomb Excitation experiment with a $^{88}$Kr radioactive beam. The motivation includes a search for $Mixed$ $Symmetry$ states predicted by the IBM-2 model, gathering more spectroscopy data about the $^{88}$Kr nucleus and extending shape coexistence studies (performed previously by the proposers for neutron-deficient Kr isotopes) to the neutron-rich side. The proposed experiment will provide data complementary to the Coulomb Excitation of a relativistic $^{88}$Kr beam proposed by D. Tonev et al. for a RISING experiment. A total of 12 days of beam time is necessary for the experiment, equally divided into two runs. One run with a 2.2 MeV/A beam energy on a $^{48}$Ti target and a second run with the maximum available REX energy of 3.1 MeV/A on a $^{208}$Pb target are requested. Using either a UC$_{x}$ or ThC$_{x}$ fissioning primary target coupled with a plasma source by a cooled transfer line seems to be the best choice for the proposed experime...

  1. Evolution of Single Particle and Collective properties in the Neutron-Rich Mg Isotopes

    CERN Multimedia

    Reiter, P; Wiens, A; Fitting, J; Lauer, M; Van duppen, P L E; Finke, F

    2002-01-01

    We propose to study the single particle and collective properties of the neutron-rich Mg isotopes in transfer reactions and Coulomb excitation using REX-ISOLDE and MINIBALL. From the Coulomb excitation measurement precise and largely model independent B( E2 ; 0$^{+}_{g.s.}\\rightarrow$ 2$^{+}_{1}$ ) will be determined for the even-even isotopes. For the odd isotopes the distribution of the E2 strength over a few low-lying states will be measured. The sign of the M1/E2 mixing ratio, extracted from angular distributions, is characteristic of the sign of the deformation, as is the resulting level scheme. The neutron-pickup channel in the transfer reactions will allow for a determination of the single particle properties (spin, parity, spectroscopic factors) of these nuclei. This information will give new insights in changes of nuclear structure in the vicinity of the island of deformation around $^{32}$Mg. A total of 24 shifts of REX beam time is requested.

  2. Low-energy Coulomb excitation of neutron-rich zinc isotopes

    CERN Document Server

    Van de Walle, J; Behrens, T; Bildstein, V; Blazhev, A; Cederkäll, J; Clément, E; Cocolios, T E; Davinson, T; Delahaye, P; Eberth, J; Ekström, A; Fedorov, D V; Fedosseev, V; Fraile, L M; Franchoo, S; Gernhäuser, R; Georgiev, G; Habs, D; Heyde, K; Huber, G; Huyse, M; Ibrahim, F; Ivanov, O; Iwanicki, J; Jolie, J; Kester, O; Köster, U; Kröll, T; Krücken, R; Lauer, M; Lisetskiy, A F; Lutter, R; Marsh, B A; Mayet, P; Niedermaier, O; Pantea, M; Raabe, R; Reiter, P; Sawicka, M; Scheit, H; Schrieder, G; Schwalm, D; Seliverstov, M D; Sieber, T; Sletten, G; Smirnova, N; Stanoiu, M; Stefanescu, I; Thomas, J C; Valiente-Dobón, J J; Van Duppen, P; Verney, D; Voulot, D; Warr, N; Weisshaar, D; Wenander, F; Wolf, B H; Zielinska, M

    2009-01-01

    At the radioactive ion beam facility REX-ISOLDE, neutron-rich zinc isotopes were investigated using low-energy Coulomb excitation. These experiments have resulted in B(E2,20) values in 74-80Zn, B(E2,42) values in 74,76Zn and the determination of the energy of the first excited 2 states in 78,80Zn. The zinc isotopes were produced by high-energy proton- (A=74,76,80) and neutron- (A=78) induced fission of 238U, combined with selective laser ionization and mass separation. The isobaric beam was postaccelerated by the REX linear accelerator and Coulomb excitation was induced on a thin secondary target, which was surrounded by the MINIBALL germanium detector array. In this work, it is shown how the selective laser ionization can be used to deal with the considerable isobaric beam contamination and how a reliable normalization of the experiment can be achieved. The results for zinc isotopes and the N=50 isotones are compared to collective model predictions and state-of-the-art large-scale shell-model calculations, i...

  3. 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.

  4. Study of the structure of yrast bands of neutron-rich 114-124Pd isotopes

    Science.gov (United States)

    Chaudhary, Ritu; Devi, Rani; Khosa, S. K.

    2018-02-01

    The projected shell model calculations have been carried out in the neutron-rich 114-124Pd isotopic mass chain. The results have been obtained for the deformation systematics of E(2+1) and E(4+1)/E({2}+1) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena, B( E2) transition probabilities and g-factors in these nuclei. The observed systematics of E(2+1) values and R_{42} ratios in the 114-124Pd isotopic mass chain indicate that there is a decrease of collectivity as the neutron number increases from 68 to 78. The occurrence of backbending in these nuclei as well as the changes in the calculated B( E2) transition probabilities and g -factors predict that there are changes in the structure of yrast bands in these nuclei. These changes occur at the spin where there is crossing of g-band by 2-qp bands. The predicted backbendings and predicted values of B( E2)s and g-factors in some of the isotopes need to be confirmed experimentally.

  5. Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

  6. 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.)

  7. Measurements of fast neutron spectra in iron, uranium and sodium-iron assemblies

    International Nuclear Information System (INIS)

    Kappler, F.; Pieroni, N.; Rusch, D.; Schmidt, A.; Wattecamps, E.; Werle, H.

    1979-01-01

    Spectrum measurements were performed at the fast subcritical facility SUAK to test nuclear data and computer codes used in fast reactor calculations. In order to obtain a specific and quantitative interpretation of discrepancies between measured and calculated spectrum, homogeneous assemblies consisting of single materials were investigated. The leakage spectrum of iron and uranium cylinders was measured by time-of-flight and proportional counters. Time-dependent leakage spectra were measured by a NE 213 liquid scintillator. It was demonstrated that the investigation of time-dependent spectra is a sensitive test of inelastic scattering cross section data. The effect of an interface on fast neutron spectra was also investigated by measuring space dependent spectra across a sodium-iron interface. The measured spectra of these assemblies are suitable for testing the adequacy of computational approximations and cross section data. (author)

  8. Neutron activation analysis of the MIBI, MAG-3 and sodium fitate active principles

    International Nuclear Information System (INIS)

    Capote Rodriguez, G.; Perez Sayaz, G.; Moreno Bermudez, J.; Ribeiro Guevara, S.; Molina Insfran, J.

    1996-01-01

    Neutron activation analysis (NAA) both instrumental (INAA) and radiochemical (RNAA) are extensively applied for determination of minor and trace elements in samples of quite different origin and composition. Particularly, the application of INAA is well recognized for analysis of microquantitis of heavy metals as well as toxic elements in biological samples. In this work the possibility of the determination of MIBI, MAG-3 and sodium fitate elemental composition by INAA was investigated Analytical information about the concentration and/or detection limits of some toxic elements (Hg, Cd, As, Se, Sb) and other trace elements of interest (Fe, Cr, Co, Zn, Br) was obtained. The samples were irradiated in the CAb Ra-6 nuclear research reactor

  9. Production and separation of neutron-rich rare isotopes around and below the Fermi energy

    CERN Document Server

    Souliotis, G A; Chubarian, G; Yennello, S J

    2003-01-01

    The production of n-rich rare isotopes around and below the Fermi energy is investigated using beams from the K500 Superconducting Cyclotron and the MARS recoil separator at the Cyclotron Institute of Texas A and M University. The experimental results from the reactions of 25 MeV/nucleon sup 8 sup 6 Kr + sup 6 sup 4 Ni and 21 MeV/nucleon sup 1 sup 2 sup 4 Sn + sup 1 sup 2 sup 4 Sn are presented and compared with simulations. The calculations involve a deep inelastic transfer (DIT) code for the primary interaction stage followed by the code GEMINI for the de-excitation stage. The results are also compared with the EPAX parametrization. The data on the 25 MeV/nucleon sup 8 sup 6 Kr + sup 6 sup 4 Ni reaction show that both proton-removal and several-neutron pick-up isotopes are produced. An enhancement is observed in the production of n-rich isotopes close to the projectile relative to the predictions of DIT/GEMINI and the expectations of EPAX. The data of 21 MeV/nucleon sup 1 sup 2 sup 4 Sn + sup 1 sup 2 sup 4 ...

  10. Reactions of neutron-rich Sn isotopes investigated at relativistic energies at R{sup 3}B

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

    Reactions of neutron-rich tin isotopes in a mass range of A=124 to A=134 have been measured at the R{sup 3}B setup at GSI in inverse kinematics. Due to the neutron excess, which results in a weaker binding of the valence neutrons such isotopes are expected to form a neutron skin. The investigation of this phenomenon is an important goal in nuclear-structure physics. Reactions of the tin isotopes with different targets have been performed kinematically complete. The taken data set therefore allows for the extraction of the neutron-skin thickness from two independent reaction channels. These are dipole excitations on the one hand and nuclear-induced reactions on the other hand. This contribution focuses on the latter mechanism. The analysis techniques which are used to extract the total charge-changing as well as the total neutron-removal cross section are presented using the example of {sup 124}Sn. The total neutron-removal cross section is of particular interest because of its high sensitivity to the neutron-skin thickness.

  11. Probing the collectivity in neutron-rich Cd isotopes via γ-ray spectroscopy

    International Nuclear Information System (INIS)

    Naqvi, Farheen

    2011-01-01

    The spin and configurational structure of excited states of 127 Cd, 125 Cd and 129 Cd, having two proton and three, five and one neutron holes, respectively in the doubly magic 132 Sn core have been studied. The isomeric states in Cd isotopes were populated in the fragmentation of a 136 Xe beam at an energy of 750 MeV/u on a 9 Be target of 4 g/cm 2 . The experiment was performed at GSI Darmstadt. The neutron-rich Cd isotopes were selected using the Bρ - ΔE - Bρ method at the FRagment Separator (FRS). Event by event identification of fragments in terms of their A (mass) and Z (charge) was provided by the standard FRS detectors. The reaction residues were implanted in a plastic stopper surrounded by 15 Ge cluster detectors from the RISING array to detect the γ decays. In 127 Cd, an isomeric state with a half-life of 17.5(3) μs has been detected. This yrast (19/2) + isomer is proposed to have mixed proton-neutron configurations and to decay by two competing stretched M2 and E3 transitions. Experimental results are compared with the isotone 129 Sn. In 125 Cd, apart from the previously observed (19/2) + isomer, two new metastable states at 3896 keV and 2141 keV have been detected. A half-life of 13.6(2) μs was measured for the (19/2) + isomer, having a decay structure similar to the corresponding isomeric state in 127 Cd. The higher lying isomers have a half-life of 3.1(1) μs and 2.5(15) ns, respectively. Time distributions of delayed γ transitions and γγ-coincidence relations were exploited to construct decay schemes for the two nuclei. Comparison of the experimental data with shell-model calculations is also discussed. The new information provides input for the proton-neutron interaction in nuclei around the doubly magic 132 Sn core. The γ decays of the isomeric states in 129 Cd were not observed experimentally. The reasons for the non-observation of delayed γ rays for 129 Cd are either an isomeric half-life of less than 93 ns based on the experimentally

  12. Shape Evolution in Neutron-Rich Krypton Isotopes Beyond N=60: First Spectroscopy of ^{98,100}Kr.

    Science.gov (United States)

    Flavigny, F; Doornenbal, P; Obertelli, A; Delaroche, J-P; Girod, M; Libert, J; Rodriguez, T R; Authelet, G; Baba, H; Calvet, D; Château, F; Chen, S; Corsi, A; Delbart, A; Gheller, J-M; Giganon, A; Gillibert, A; Lapoux, V; Motobayashi, T; Niikura, M; Paul, N; Roussé, J-Y; Sakurai, H; Santamaria, C; Steppenbeck, D; Taniuchi, R; Uesaka, T; Ando, T; Arici, T; Blazhev, A; Browne, F; Bruce, A; Carroll, R; Chung, L X; Cortés, M L; Dewald, M; Ding, B; Franchoo, S; Górska, M; Gottardo, A; Jungclaus, A; Lee, J; Lettmann, M; Linh, B D; Liu, J; Liu, Z; Lizarazo, C; Momiyama, S; Moschner, K; Nagamine, S; Nakatsuka, N; Nita, C; Nobs, C R; Olivier, L; Orlandi, R; Patel, Z; Podolyák, Zs; Rudigier, M; Saito, T; Shand, C; Söderström, P A; Stefan, I; Vaquero, V; Werner, V; Wimmer, K; Xu, Z

    2017-06-16

    We report on the first γ-ray spectroscopy of low-lying states in neutron-rich ^{98,100}Kr isotopes obtained from ^{99,101}Rb(p,2p) reactions at ∼220  MeV/nucleon. A reduction of the 2_{1}^{+} state energies beyond N=60 demonstrates a significant increase of deformation, shifted in neutron number compared to the sharper transition observed in strontium and zirconium isotopes. State-of-the-art beyond-mean-field calculations using the Gogny D1S interaction predict level energies in good agreement with experimental results. The identification of a low-lying (0_{2}^{+}, 2_{2}^{+}) state in ^{98}Kr provides the first experimental evidence of a competing configuration at low energy in neutron-rich krypton isotopes consistent with the oblate-prolate shape coexistence picture suggested by theory.

  13. Precision mass measurements on neutron-rich Zn isotopes and their consequences on the astrophysical r-process

    Energy Technology Data Exchange (ETDEWEB)

    Baruah, Sudarshan

    2008-07-15

    The rapid neutron-capture or the r-process is responsible for the origin of about half of the neutron-rich atomic nuclei in the universe heavier than iron. For the calculation of the abundances of those nuclei, atomic masses are required as one of the input parameters with very high precision. In the present work, the masses of the neutron rich Zn isotopes (A=71 to 81) lying in the r-process path have been measured in the ISOLTRAP experiment at ISOLDE/CERN. The mass of {sup 81}Zn has been measured directly for the rst time. The half-lives of the nuclides ranged from 46.5 h ({sup 72}Zn) down to 290 ms ({sup 81}Zn). In case of all the nuclides, the relative mass uncertainty ({delta}m=m) achieved was in the order of 10{sup -8} corresponding to a 100-fold improvement in precision over previous measurements. (orig.)

  14. Precision mass measurements on neutron-rich Zn isotopes and their consequences on the astrophysical r-process

    International Nuclear Information System (INIS)

    Baruah, Sudarshan

    2008-07-01

    The rapid neutron-capture or the r-process is responsible for the origin of about half of the neutron-rich atomic nuclei in the universe heavier than iron. For the calculation of the abundances of those nuclei, atomic masses are required as one of the input parameters with very high precision. In the present work, the masses of the neutron rich Zn isotopes (A=71 to 81) lying in the r-process path have been measured in the ISOLTRAP experiment at ISOLDE/CERN. The mass of 81 Zn has been measured directly for the rst time. The half-lives of the nuclides ranged from 46.5 h ( 72 Zn) down to 290 ms ( 81 Zn). In case of all the nuclides, the relative mass uncertainty (Δm=m) achieved was in the order of 10 -8 corresponding to a 100-fold improvement in precision over previous measurements. (orig.)

  15. Using quasi-elastic neutron diffraction to study positive electrode for lithium and sodium-ion batteries

    International Nuclear Information System (INIS)

    Pramudita, James C.; Sharma, Neeraj

    2015-01-01

    Sodium-ion batteries has recently been proposed as the alternative for lithium-ion batteries to be the low cost energy storage system. However, challenges still remains for the development of sodium-ion batteries. Optimization of electrode materials and electrolyte capable of insertion/extraction of sodium-ion in a safe and economic way under high current density is needed in order to produce commercially viable sodium-ion batteries. While possible positive electrode material is more prevalent than negative electrode material, many of these material still need further understanding. Quasi-elastic Neutron Scatteringis a technique that utilize the inelastic Neutron Scatteringthat can be used to study solid-state diffusion in materials. This technique can be used to study the diffusion of sodium-ion under electric field through the electrolyte and positive electrode materials in order to further understand the mechanism of sodium insertion/extraction in a working battery. This technique can also be used to study available positive electrode material for lithium-ion batteries to further understand the mechanism of lithium-ion diffusion in current working lithiumion batteries.

  16. Boron neutron capture irradiation of the rat spinal cord: effects of variable doses of borocaptate sodium

    International Nuclear Information System (INIS)

    Morris, Gerard M.; Coderre, Jeffrey A.; Hopewell, John W.; Micca, Peggy L.; Fisher, Craig

    1996-01-01

    The Fischer 344 rat spinal cord model has been used to evaluate the response of the central nervous system to boron neutron capture irradiation with variable doses of the neutron capture agent, borocaptate sodium (BSH). Three doses of BSH, 190, 140 and 80 mg/kg body weight, administered by i.p. injection, were used to establish the time course of 10 B accumulation in and removal from the blood. After administration of the two lower doses of BSH, blood 10 B levels peaked at 0.5 h after injection, with no significant (P > 0.1) change at 1 h after injection. Beyond this time point, levels of 10 B in the blood began to decrease after a dose of 80 mg/kg BSH, but remained constant until 3 h after administration after the two higher doses of BSH. Myelopathy developed after latent intervals of 20.4 ± 0.1, 20.8 ± 1.4, 15.0 ± 0.8, 15.4 ± 0.4 and 15.6 ± 0.4 weeks, following irradiation with thermal neutrons in combination with BSH at doses of 20, 40, 80, 140 and 190 mg/kg body weight, respectively. The radiation-induced lesion in the spinal cord was white matter necrosis. ED 50 values for myelopathy were calculated from probit-fitted dose-effect curves. Expressed as total physical absorbed doses, these values were 20.7 ± 1.9, 24.9 ± 1.2, 27.2 ± 0.9, 28.4 ± 0.6 and 32.4 ± 1.9 Gy after irradiation with thermal neutrons in the presence of 20, 40, 80, 140 and 190 mg/kg body weight of BSH, respectively. The compound biological effectiveness (CBE) factor values, estimated from this data, were in the range 0.49-0.55. There was no significant (P >0.1) variation in the CBE factor for BSH as a function of increasing 10 B concentration in the blood. It was concluded that there was no significant synergistic interaction between the low and high linear energy transfer (LET) components of the boron neutron capture (BNC) radiation field

  17. Neutronics aspects associated to irregular lattices in sodium fast reactors cores

    International Nuclear Information System (INIS)

    Gentili, Michele

    2015-01-01

    The fuel assemblies of SFR cores (sodium fast reactors) are normally arranged in hexagonal regular lattices, whose compactness is ensured in nominal operating conditions by thermal expansion of assemblies pads disposed on the six assembly wrapper faces. During the reactor operations, thermal expansion phenomena and irradiation creep phenomena occur and they cause the fuel assemblies to bow and to deform both radially and axially. The main goal of this PhD is the understanding of the neutronic aspects and phenomena occurring in case of core and lattice deformations, as much as the design and implementation of deterministic neutronic calculation schemes and methods in order to evaluate the consequences for the core design activities and the safety analysis. The first part of this work is focused on the development of an analytical model with the purpose to identify the neutronic phenomena that are the main contributors to the reactivity changes induced by lattice and core deformations. A first scheme based on the spatial mesh projection method has been conceived and implemented for the ERANOS codes (BISTRO, H3D and VARIANT) and to the SNATCH solver. The second calculation scheme propose is based on mesh deformation: the computing mesh is deformed as a function of the assembly displacement field. This methodology has been implemented for the solver SNATCH, which normally allows the Boltzmann equation to be solved for a regular mesh. Finally, an iterative method has been developed in order to fulfill an a-priori estimation of the maximal reactivity insertion as a function of the postulated mechanical energy provided to the core, as much as the deformation causing it. (author) [fr

  18. Krypton and xenon in Apollo 14 samples - Fission and neutron capture effects in gas-rich samples

    Science.gov (United States)

    Drozd, R.; Hohenberg, C.; Morgan, C.

    1975-01-01

    Gas-rich Apollo 14 breccias and trench soil are examined for fission xenon from the decay of the extinct isotopes Pu-244 and I-129, and some samples have been found to have an excess fission component which apparently was incorporated after decay elsewhere and was not produced by in situ decay. Two samples have excess Xe-129 resulting from the decay of I-129. The excess is correlated at low temperatures with excess Xe-128 resulting from neutron capture on I-127. This neutron capture effect is accompanied by related low-temperature excesses of Kr-80 and Kr-82 from neutron capture on the bromine isotopes. Surface correlated concentrations of iodine and bromine are calculated from the neutron capture excesses.

  19. Synthesis of magnetite from iron-rich mine water using sodium carbonate

    CSIR Research Space (South Africa)

    Akinwekomi, V

    2017-06-01

    Full Text Available is highly mineralised and technologies are required for the processing of the final sludge for possible industrial application. Conventionally, magnetite is synthesized using iron-rich, industrial grade chemical reagents making magnetite expensive to produce...

  20. 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.

  1. Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.

    Science.gov (United States)

    Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

    2013-01-01

    Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping.

  2. Neutron-rich Λ-Hypernuclei study with the FINUDA experiment

    Directory of Open Access Journals (Sweden)

    Botta E.

    2014-03-01

    Full Text Available The FINUDA experiment at DAΦNE, Frascati, has found evidence for the neutron-rich hypernucleus HΛ6${}_ \\wedge ^6{\\rm{H}}$ studying (π+, π− pairs in coincidence from the Kstop−+L6i→HΛ6+π+$K_{{\\rm{stop}}}^ - + {}^{\\rm{6}}{\\rm{Li}} \\to {}_ \\wedge ^6{\\rm{H}} + {\\pi ^ + }$ production reaction followed by HΛ6→H6e +π−${}_ \\wedge ^6{\\rm{H}} \\to {}^6{\\rm{He + }}{\\pi ^ - }$ weak decay. The production rate of HΛ6${}_ \\wedge ^6{\\rm{H}}$ undergoing this two-body π− decay has been found to be (2.9±2.0⋅10−6/Kstop−$(2.9 \\pm 2.0 \\cdot {10^{ - 6}}/K_{{\\rm{stop}}}^ - $. Its binding energy has been evaluated to be BΛ(HΛ6=(4.0±1.1${B_ \\wedge }({}_ \\wedge ^6H = (4.0 \\pm 1.1$ MeV with respect to (H5+Λ$({}^5{\\rm{H}} + \\Lambda $, jointly from production and decay. A systematic difference of (0.98 ± 0.74 MeV between BΛ values derived separately from decay and from production has been tentatively assigned to the HΛ6 0g.s.+→1+${}_\\Lambda ^6{\\rm{H 0}}_{{\\rm{g}}{\\rm{.s}}{\\rm{.}}}^ + \\to {1^ + }$ excitation. A similar investigation has been carried out for the neutron-rich hypernucleus HΛ9e${}_\\Lambda ^9{\\rm{He}}$ studying the Kstop−+B9e→HΛ9e+π+$K_{{\\rm{stop}}}^ - + {}_{}^{\\rm{9}}{\\rm{Be}} \\to {}_\\Lambda ^9{\\rm{He}} + {\\pi ^ + }$ reaction in coincidence with the H Λ 9e→ L 9i +  π −${}_\\Lambda ^9{\\rm{He}} \\to {}_{}^{\\rm{9}}{\\rm{Li + }}{\\pi ^ - }$ weak decay; an upper limit for the production rate of HΛ9e${}_\\Lambda ^9{\\rm{He}}$ undergoing the two-body π− decay has been found to be 4.2⋅10 −6 /K stop− $4.2 \\cdot {10^{ - 6}}/{\\rm{K}}_{stop}^ - $ (90% C.L..

  3. Study of the Na-C-O and Na-H-O ternary systems in the sodium rich corner

    International Nuclear Information System (INIS)

    Maupre, J.-P.

    1978-02-01

    The purpose of this study is to provide a contribution to the understanding of the sodium - carbon - oxygen and sodium - hydrogen - oxygen ternary systems in the sodium rich corner. In order to do this the Na-NaH-Na 2 O-NaOH phase diagram was completed and the Na-Na 2 O-Na 2 CO 3 -C phase diagram was outlined. This work is made up of two parts. The first is devoted to a critical literature survey essential to establish correct phase diagrams. The second is an experimental study followed by a discussion collating our finding to the literary data. The basic experimental technique used is differential thermal analysis (DTA) but it has been completed by quenching, X-ray and chemical analysis methods. The proposed phase diagrams imply that Na-NaH-Na 2 O-NaOH and Na-Na 2 O-Na 2 CO 3 -C systems are reciprocal ternary systems. Temperatures of stable pairs reversal are respectively 410 and 690 0 C. The stable pairs are Na-NaOH and Na-Na 2 CO 3 at elevated temperature, Na 2 O-NaH and Na 2 O-C at low temperature [fr

  4. 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

  5. Velocity determination of neutron-rich projectile fragments with a ring-imaging Cherenkov detector

    International Nuclear Information System (INIS)

    Zeitelhack, K.

    1992-11-01

    For the velocity determination of relativistic heavy ions (A>100) in the energy range 300A.MeV ≤ E kin ≤ 2A.GeV a highly resolving, compact ring-imaging Cherenkov counter with large dynamical measurement range was developed. The Cherenkov light cone emitted in the flight of a relativistic heavy ion by a liquid layer (C 6 F 14 ) is focused on the entrance window of a one-dimensional position-resolving VUV-sensitive photon detector. This gas detector is operated at atmospheric pressure with a mixture of 90% methane and 10% isobutane with 0.04% TMAE as photosensitive admixture. For 725A.MeV 129 Xe ions a velocity resolution Δβ/β=1.8.10 -3 and a nuclear charge-number resolution ΔZ/Z=5.1.10 -2 was reached. The over the photon energy range 5.4 eV ≤ E γ ≤ 7.2 eV averaged detection efficiency of the detector system was determined to ε tot =2.8%>. At the 0deg magnet spectrometer Fragmentseparator of the GSI Darmstadt the RICH detector was for the first time applied for the identification of nuclear charge number and mass of heavy relativistic projectile fragments. In the experiment the production cross sections of very neutron-rich nuclei by fragmentation of 136 Xe projectiles in the reaction 76A.MeV 136 Xe on 27 Al were determined. From the measured production erates for the production of the double-magic nucleus 132 Zn in this reaction a cross section of σ=(0.4± 0.3 0.6 ) μbarn can be extrapolated. (orig./HSI) [de

  6. Study of photosensitization reaction progress in a 96 well plate with photosensitizer rich condition using Talaporfin sodium

    Science.gov (United States)

    Ogawa, Emiyu; Takahashi, Mei; Arai, Tsunenori

    2013-02-01

    To quantitatively investigate photosensitization reaction in vitro against myocardial cells with photosensitizer rich condition in solution using Talaporfin sodium in the well of a 96 well plate, we studied photosensitization reaction progress in this well. We have proposed non-thermal conduction block of myocardium tissue using the photosensitization reaction with laser irradiation shortly after Talaporfin sodium injection. In above situation, the photosensitizer is located outside the myocardial cells in high concentration. To understand interaction of the photosensitization reaction in which the photosensitizer distributes outside cells, the photosensitization reaction progress in the well was studied. Talaporfin sodium (799.69 MW) solution and a 663 nm diode laser were used. The photosensitizer solution concentrations of 12.5-37.5 μM were employed. The photosensitizer fluorescence with 0.29 W/cm2 in irradiance, which was optimized in previous cell death study, was measured during the laser irradiation until 40 J/cm2. The photosensitizer solution absorbance and dissolved oxygen pressure after the laser irradiation were also measured. We found that the photosensitization reaction progress had 2 distinctive phases of different reaction rate: rapid photosensitization reaction consuming dissolved oxygen and gentle photosensitization reaction with oxygen diffusion from the solution-air boundary. The dissolved oxygen pressure and photosensitizer solution absorbance were 30% and 80% of the initial values after the laser irradiation, respectively. Therefore, oxygen was rate-controlling factor of the photosensitization reaction in the well with the photosensitizer rich condition. In the oxygen diffusion phase, the oxygen pressure was maintained around 40 mmHg until the laser irradiation of 40 J/cm2 and it is similar to that of myocardium tissue in vivo. We think that our 96 well plate in vitro system may simulate PDT in myocardial tissue with photosensitization reaction

  7. Electrolyte Balance of the Inner Ear Investigated by Neutron Activation Analysis of the Sodium and Potassium Content

    International Nuclear Information System (INIS)

    Ördögh, Mary; Miriszlai, E.

    1967-01-01

    Even the few experimental data that have been obtained from investigations of the inner ear are an important contribution to our biochemical knowledge of the sense organs. The apparent discrepancies between some experimental results have prompted comparative studies on the sodium and potassium concentrations in the inner-ear fluids, the liquor cerebrospinalis, the mammalian and human serum. The results of these studies are expected to give a good approximation of the intracellular and extracellular electrolyte concentrations and to yield important information on the physiological and pathological conditions of the inner ear as well as on the mechanism of hearing. The experimental material is obtained from guinea pigs by penetration through the round window (fenestra rotunda). The sodium and potassium content is determined by neutron activation analysis. Potassium is precipitated from the irradiated samples by sodium tetraphenyl borate reagent, so that the sodium activity retained by the filtrate can be directly counted. Since a single precipitation of potassium does not yield end products free from sodium contamination, the precipitate is dissolved in acetone and precipitated again with sodium tetraphenyl borate. The product of the second precipitation is radiochemically pure. In simultaneous experiments, potassium was separated from the much higher sodium activity by isotopic exchange. The irradiated sample is added to an experimentally determined inactive potassium tetraphenyl borate precipitate that adsorbs the total potassium activity present without adsorbing any sodium. The separation of potassium by isotopic exchange has the advantage of yielding in a single step a sufficiently pure product without any sodium contamination. For comparison, sodium and potassium were also determined by flame photometry. (author)

  8. First-principles investigation of neutron-irradiation-induced point defects in B4C, a neutron absorber for sodium-cooled fast nuclear reactors

    Science.gov (United States)

    You, Yan; Yoshida, Katsumi; Yano, Toyohiko

    2018-05-01

    Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.

  9. 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

  10. 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.)

  11. 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...

  12. Shear viscosity of neutron-rich nucleonic matter near its liquid–gas phase transition

    International Nuclear Information System (INIS)

    Xu, Jun; Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Ma, Yu Gang

    2013-01-01

    Within a relaxation time approach using free nucleon–nucleon cross sections modified by the in-medium nucleon masses that are determined from an isospin- and momentum-dependent effective nucleon–nucleon interaction, we investigate the specific shear viscosity (η/s) of neutron-rich nucleonic matter near its liquid–gas phase transition. It is found that as the nucleonic matter is heated at fixed pressure or compressed at fixed temperature, its specific shear viscosity shows a valley shape in the temperature or density dependence, with the minimum located at the boundary of the phase transition. Moreover, the value of η/s drops suddenly at the first-order liquid–gas phase transition temperature, reaching as low as 4–5 times the KSS bound of ℏ/4π. However, it varies smoothly for the second-order liquid–gas phase transition. Effects of the isospin degree of freedom and the nuclear symmetry energy on the value of η/s are also discussed

  13. Nuclear structure studies of the neutron-rich Rubidium isotopes using Coulomb excitation

    CERN Multimedia

    Reiter, P; Blazhev, A A; Voulot, D; Meot, V H; Simpson, G S; Georgiev, G P; Gaudefroy, L; Roig, O

    We propose to study the properties of odd-mass neutron-rich rubidium isotopes by the Coulomb-excitation technique, using the Miniball array coupled to the REX-ISOLDE facility. The results from similar measurements from the recent years (e.g. for the odd-mass and the odd-odd Cu isotopes, IS435) have shown the strong potential in such measurements for gaining information both for single-particle-like and collective states in exotic nuclei. Since there is practically no experimental information for excited states in the odd-mass Rb isotopes beyond $^{93}$Rb, the present study should be able to provide new data in a region of spherical ($^{93}$Rb and $^{95}$Rb) as well as well-deformed nuclei ($^{97}$Rb and $^{99}$Rb). Of particular interest is the rapid shape change that occurs when going from $^{95}$Rb (${\\varepsilon}_{2}$=0.06) to $^{97}$Rb (${\\varepsilon}_{2}$=0.3). These results should be of significant astrophysical interest as well, due to the close proximity of the r-process path.

  14. Isomers in neutron-rich A ∼ 190 nuclides from 208Pb fragmentation

    International Nuclear Information System (INIS)

    Rykaczewski, Krzysztof Piotr; Caamano, M.; Banu, A.; Walker, P.M.; Morton, N.H.; Regan, P. H.; Regan, Patrick H; Pfutzner, M.; Podolyak, Zs.; Gerl, J.; Hellstrom, M.; Mayet, P.; Miernik, K.; Mineva, M.N.; Aprahamian, A.; Benlliure, J.; Bruce, A.M.; Butler, P.A.; Cortina Gil, D.; Cullen, D.M.; Doring, J.; Enqvist, T.; Fox, C.; Garces Narro, J.; Geissel, H.; Gelletly, W.; Giovinazzo, J.; Gorska, M.; Grawe, H.; Grzywacz, R.; Kleinbohl, A.; Korten, W.; Lewitowicz, M.; Lucas, R.; Mach, H.; O'Leary, C.D.; De Oliveira, F.; Pearson, C.J.; Rejmund, F.

    2004-01-01

    Relativistic projectile fragmentation of 208 Pb has been used to produce isomers in neutron-rich, A ∼ 190 nuclides. A forward-focusing spectrometer provided ion-by-ion mass and charge identification. The detection of gamma-rays emitted by stopped ions has led to the assignment of isomers in 188 Ta, 190 W, 192 Re, 193 Re, 195 Os, 197 Ir, 198 Ir, 200 Pt, 201 Pt, 202 Pt and 203 Au, with half-lives ranging from approximately 10 ns to 1 ms. Tentative isomer information has been found also for 174 Er, 175 Er, 185 Hf, 191 Re, 194 Re and 199 Ir. In most cases, time-correlated, singles gamma-ray events provided the first spectroscopic data on excited states for each nuclide. In 200 Pt and 201 Pt, the assignments are supported by gamma-gamma coincidences. Isomeric ratios provide additional information, such as half-life and transition energy constraints in particular cases. The level structures of the platinum isotopes are discussed, and comparisons are made with isomer systematics

  15. 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.

  16. Evolution of deformation in neutron-rich Ba isotopes up to A =150

    Science.gov (United States)

    Licǎ, R.; Benzoni, G.; Rodríguez, T. R.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Morales, A. I.; Madurga, M.; Sotty, C. O.; Vedia, V.; De Witte, H.; Benito, J.; Bernard, R. N.; Berry, T.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernandez-Martínez, G.; Fynbo, H.; Greenlees, P. T.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Lund, M. V.; Mǎrginean, N.; Mǎrginean, R.; Mihai, C.; Mihai, R. E.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Regis, J. M.; Robledo, L. M.; Rotaru, F.; Saed-Samii, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.; IDS Collaboration

    2018-02-01

    The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N =90 . To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z =56 isotopic chain accessible at present, Ba,150148, has been studied via β decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive- and negative-parity low-spin excited states of 150Ba and presents an extension of the β -decay scheme of 148Cs. Employing the fast timing technique, half-lives for the 21+ level in both nuclei have been determined, resulting in T1 /2=1.51 (1 ) ns for 148Ba and T1 /2=3.4 (2 ) ns for 150Ba. The systematics of low-spin states, together with the experimental determination of the B (E 2 :2+→0+) transition probabilities, indicate an increasing collectivity in Ba-150148, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.

  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. 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.

  19. 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...

  20. Isomer-delayed gamma-ray spectroscopy of neutron-rich 166Tb

    Directory of Open Access Journals (Sweden)

    Gurgi L.A.

    2017-01-01

    Full Text Available This short paper presents the identification of a metastable, isomeric-state decay in the neutron-rich odd-odd, prolate-deformed nucleus 166Tb. The nucleus of interest was formed using the in-flight fission of a 345 MeV per nucleon 238U primary beam at the RIBF facility, RIKEN, Japan. Gamma-ray transitions decaying from the observed isomeric states in 166Tb were identified using the EURICA gamma-ray spectrometer, positioned at the final focus of the BigRIPS fragments separator. The current work identifies a single discrete gamma-ray transition of energy 119 keV which de-excites an isomeric state in 166Tb with a measured half-life of 3.5(4 μs. The multipolarity assignment for this transition is an electric dipole and is made on the basis internal conversion and decay lifetime arguments. Possible two quasi-particle Nilsson configurations for the initial and final states which are linked by this transition in 166Tb are made on the basis of comparison with Blocked BCS Nilsson calculations, with the predicted ground state configuration for this nucleus arising from the coupling of the v(1-/2[521] and π(3+/2 Nilsson orbitals.

  1. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr

    CERN Multimedia

    Clement, E; Siem, S; Czosnyka, T

    2007-01-01

    The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...

  2. 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

  3. Evolution of nuclear structure in neutron-rich odd-Zn isotopes and isomers

    Directory of Open Access Journals (Sweden)

    C. Wraith

    2017-08-01

    Full Text Available Collinear laser spectroscopy was performed on Zn (Z=30 isotopes at ISOLDE, CERN. The study of hyperfine spectra of nuclei across the Zn isotopic chain, N=33–49, allowed the measurement of nuclear spins for the ground and isomeric states in odd-A neutron-rich nuclei up to N=50. Exactly one long-lived (>10 ms isomeric state has been established in each 69–79Zn isotope. The nuclear magnetic dipole moments and spectroscopic quadrupole moments are well reproduced by large-scale shell–model calculations in the f5pg9 and fpg9d5 model spaces, thus establishing the dominant term in their wave function. The magnetic moment of the intruder Iπ=1/2+ isomer in 79Zn is reproduced only if the νs1/2 orbital is added to the valence space, as realized in the recently developed PFSDG-U interaction. The spin and moments of the low-lying isomeric state in 73Zn suggest a strong onset of deformation at N=43, while the progression towards 79Zn points to the stability of the Z=28 and N=50 shell gaps, supporting the magicity of 78Ni.

  4. Nuclear-decay studies of neutron-rich rare-earth nuclides

    International Nuclear Information System (INIS)

    Chasteler, R.M.

    1990-01-01

    Neutron-rich rare-earth nuclei were produced in multinucleon transfer reactions of 170 Er and 176 Yb projectiles on nat W targets at the Lawrence Berkeley Laboratory SuperHILAC and their radioactive decays properties studied at the on-line mass separation facility OASIS. Two unknown isotopes, 169 Dy (t 1/2 = 39 ± 8 s) and 174 Er(t 1/2 = 3.3 ± 0.2 m) were discovered and their decay characteristics determined. The decay schemes for two previously identified isotopes, 168 Dy (t 1/2 = 8.8 ± 0.3 m) and 171 Ho (t 1/2 = 55 ± 3 s), were characterized. Evidence for a new isomer of 3.0 m 168 Ho g , 168 Ho m (t 1/2 = 132 ± 4 s) which decays by isomeric transition (IT) is presented. Beta particle endpoint energies were determined for the decay of 168 Ho g , 169 Dy, 171 Ho, and 174 Er, the resulting Qβ-values are: 2.93 ± 0.03, 3.2 ± 0.3, 3.2 ± 0.6, and 1.8 ± 0.2 MeV, respectively. These values were compared with values calculated using recent atomic mass formulae. Comparisons of various target/ion source geometries used in the OASIS mass separator facility for these multinucleon transfer reactions were performed. 73 refs., 40 figs., 11 tabs

  5. β-decay spectroscopy of neutron-rich 160,161,162Sm isotopes

    Directory of Open Access Journals (Sweden)

    Patel Z.

    2016-01-01

    Full Text Available Neutron-rich 160,161,162Sm isotopes have been populated at the RIBF, RIKEN via β first time. β-coincident γ rays were observed in all three isotopes including γ rays from the isomeric decay of 160Sm and 162Sm. The isomers in 160Sm and 162Sm have previously been observed but have been populated via β decay for the first time. The isomeric state in 162Sm is assigned a 4−v72+[ 633 ]⊗v12−[ 521 ]${4^ - }v{{7 \\over 2}^ + }\\left[ {633} \\right] \\otimes v{{1 \\over 2}^ - }\\left[ {521} \\right]$ configuration based on the decay pattern. The level schemes of 160Sm and 162Sm are presented. The ground states in the parent nuclei 160Pm and 162Pm are both assigned a 6−v72+[633]⊗π52−[532]${6^ - }v{{7 \\over 2}^ + }\\left[ {633} \\right] \\otimes \\pi {{5 \\over 2}^ - }\\left[ {532} \\right]$ configuration based on the population of states in the daughter nuclei. Blocked BCS calculations were performed to further investigate the spin-parities of the ground states in 160Pm, 161Pm, and 162Pm, and the isomeric state in 162Sm

  6. Investigation of reduced transition-strengths in neutron-rich chromium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Braunroth, Thomas; Dewald, Alfred; Fransen, Christoph; Litzinger, Julia [Institut fuer Kernphysik, Universitaet Koeln (Germany); Iwasaki, Hironori [National Superconducting Cyclotron Laboratory, MSU (United States); Lemasson, Antoine [GANIL, Laboratoire Commun DSM/CEA (France); Lenzi, Silvia [Department of Physics and Astronomy, University of Padova (Italy); INFN, Sezione di Padova (Italy)

    2015-07-01

    Neutron-rich nuclei close to N=40 are known for their rapid changes in nuclear structure. While {sup 68}Ni exhibits signatures of a shell closure, experimental data - e.g. excitation energies of the 2{sup +}{sub 1}-state and B(E2;2{sup +}{sub 1} → 0{sup +}{sub 1})-values - along the isotopic chains in even more exotic Fe and Cr-isotopes suggest a sudden rise in collective behaviour for N → 40. Lifetimes of low-lying yrast states in {sup 58,60,62}Cr were measured with the Recoil Distance Doppler-shift (RDDS) technique at NSCL, MSU (USA) to deduce model independent B(E2)-values. After fragmentation of a primary {sup 82}Se beam (E=140 AMeV) on a {sup 9}Be target and subsequent filtering with the A1900 fragment separator, high purity {sup 59,61,63}Mn-beams (E ∝ 95 AMeV) impinged on the {sup 9}Be plunger target, where excited states in the above mentioned Cr-isotopes were then populated in one proton knockout reactions. The S800 spectrograph allowed a clear recoil identification, which then lead to clean γ-spectra as measured by the Segmented Germanium Array (SeGA). Final results of this experiment will be shown and discussed in the context of state-of-the-art shell-model calculations.

  7. 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...

  8. 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)

  9. Contribution of food additives to sodium and phosphorus content of diets rich in processed foods.

    Science.gov (United States)

    Carrigan, Anna; Klinger, Andrew; Choquette, Suzanne S; Luzuriaga-McPherson, Alexandra; Bell, Emmy K; Darnell, Betty; Gutiérrez, Orlando M

    2014-01-01

    Phosphorus-based food additives increase the total phosphorus content of processed foods. However, the extent to which these additives augment total phosphorus intake per day is unclear. To examine the contribution of phosphorus-based food additives to the total phosphorus content of processed foods, separate 4-day menus for a low-additive and additive-enhanced diet were developed using Nutrition Data System for Research (NDSR) software. The low-additive diet was designed to conform to U.S. Department of Agriculture guidelines for energy and phosphorus intake (∼2,000 kcal/day and 900 mg of phosphorus per day), and it contained minimally processed foods. The additive-enhanced diet contained the same food items as the low-additive diet except that highly processed foods were substituted for minimally processed foods. Food items from both diets were collected, blended, and sent for measurement of energy and nutrient intake. The low-additive and additive-enhanced diet provided approximately 2,200 kcal, 700 mg of calcium, and 3,000 mg of potassium per day on average. Measured sodium and phosphorus content standardized per 100 mg of food was higher each day of the additive-enhanced diet as compared with the low-additive diet. When averaged over the 4 menu days, the measured phosphorus and sodium contents of the additive-enhanced diet were 606 ± 125 and 1,329 ± 642 mg higher than the low-additive diet, respectively, representing a 60% increase in total phosphorus and sodium content on average. When comparing the measured values of the additive-enhanced diet to NDSR-estimated values, there were no statistically significant differences in measured versus estimated phosphorus contents. Phosphorus and sodium additives in processed foods can substantially augment phosphorus and sodium intake, even in relatively healthy diets. Current dietary software may provide reasonable estimates of the phosphorus content in processed foods. Copyright © 2014 National Kidney

  10. Production of neutron-rich nuclides in the vicinity of N = 126 shell closure in multinucleon transfer reactions

    Directory of Open Access Journals (Sweden)

    Karpov Alexander

    2017-01-01

    Full Text Available Multinucleon transfer in low-energy nucleus-nucleus collisions is widely discussed as a method of production of yet-unknown neutron-rich nuclei hardly accessible (or inaccessible by other methods. Modeling of complicated dynamics of nuclear reactions induced by heavy ions is done within a multidimensional dynamical model of nucleus-nucleus collisions based on the Langevin equations. The model gives a continuous description of the system evolution starting from the well-separated target and projectile in the entrance channel of the reaction up to the formation of final reaction products. In this paper, rather recent sets of experimental data for the 136Xe+198Pt,208Pb reactions are analyzed together with the production cross sections for neutron-rich nuclei in the vicinity of the N = 126 magic shell.

  11. 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

  12. 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.

  13. Neutron activation analysis: study of primary interference on determination of aluminium, magnesium, manganese and sodium

    International Nuclear Information System (INIS)

    Costa, Leonardo Alves da

    2007-01-01

    The neutron activation (NAA) is an analytical technique for the determination of the elementary chemical composition. It is based on the induction of artificial radioactivity in a sample by neutrons and the resulting activity is usually measured, by gamma spectrometry. Its more relevant characteristics are the high sensibility (μg.g -1 - ng.g -1 ), accuracy and precision, capability of multi elementary analysis, low detection limits and its non destructive nature. These properties classify NAA as a very powerful analytical technique. In spite of being a versatile technique, the NAA presents limitations, one of them is related to the primary interference reactions that occur during the irradiation. The calculation of the concentration is usually based on the main reaction under thermal neutrons n X(n th , y) n+1 X but under fast flux, the reactions n+1 Y(n r , p) n+1 X e n+4 Y(n r , α) n+1 X can take place. The consequence of this interference is that the final elemental concentration will be the sum of results of the reactions and it is not possible to distinguish the real concentration. Therefore, the impact of this interference depends on the contribution of the fast neutron flux on the total neutron flux in the local irradiation channel. It means that the interference depends on how much the irradiation channel is thermalized and it is a characteristic of the reactor. In this research, several interference reactions were studied: 28 Si(n f ,p) Al on the aluminium determination; 27 Al(n f ,p) 27 Mg, on the determination of magnesium; 27 Al(n f , α) Na, on the determination of sodium and 56 Fe(n f ,p) 56 Mn on the determination of manganese. Two procedures were adopted: Method I, in which using pure standards of the elements, the 'apparent' masses of Al, Mg, Mn and Na from interfering reactions were evaluated and a ratio between the interference of the element to the interested element was determined for each studied element. In Method II, the contribution of

  14. Recent Progress in Constraining the Equation of State of Dense Neutron-Rich Nuclear Matter with Heavy-Ion Reactions

    International Nuclear Information System (INIS)

    Li Baoan; Chen Liewen; Wen Dehua; Xiao Zhigang; Xu Chang; Yong Gaochan; Zhang Ming

    2010-01-01

    The nuclear symmetry energy E sym (ρ) is the most uncertain part of the Equation of State (EOS) of dense neutron-rich nuclear matter. In this talk, we discuss the underlying physics responsible for the uncertain E sym (ρ) especially at supra-saturation densities, the circumstantial evidence for a super-soft E sym (ρ) from analyzing π - /π + ratio in relativistic heavy-ion collisions and its impacts on astrophysics and cosmology.

  15. Study of Neutron-Rich $^{124,126,128}$Cd Isotopes; Excursion from Symmetries to Shell-Model Picture

    CERN Multimedia

    Nieminen, A M; Reponen, M

    2002-01-01

    A short outline is given on a number of topics that are present in the long series of even-even Cd nuclei and therefore, may turn out to constitute an ideal test bench in order to verify a number of theoretical ideas on how collective motion, near closed shells, builds up taking into account both the valence and core nucleons when studying the nucleon correlations. Moreover, these experiments can reveal new challenges when moving towards very neutron-rich systems.

  16. In-beam γ-ray spectroscopy of the neutron rich 39Si

    International Nuclear Information System (INIS)

    Sohler, D.; Dombradi, Zs.; Achouri, N.L.; Angelique, J.C.; Bastin, B.; Azaiez, F.; Baiborodin, D.; Borcea, R.

    2009-01-01

    Complete text of publication follows. In order to clarify the role of proton excitations across the Z = 14 subshell closure in neutron-rich Si isotopes, we investigated the structure of the 14 39 Si 25 isotope, having three neutron-hole configurations with respect to an N = 28 core. The excited states of 39 Si were studied by in-beam γ-ray spectroscopy trough fragmentation of radioactive beams. The experiment was performed at the GANIL facility in France. The radioactive beams were produced by the fragmentation of the stable 48 Ca beam of 60 MeV/u energy and 4μA intensity on a 12 C target in the SISSI device. The cocktail beam produced was impinged onto a 9 Be target. The nuclei produced in the secondary fragmentation reaction were selected and unambiguously identified by the SPEG spectrometer. In the performed experiment the 39 Si nuclei were obtained via 1p, 1p1n, 2p1n and 2p2n knockout reactions from the 40,41 P and 42,43 S secondary beams. To measure the γ rays emitted from the excited states, the secondary target was surrounded by the 4π 'Chateau de Crystal' array consisting of 74 BaF 2 scintillators. The γ-ray spectra were generated by gating event-by-event on the incoming secondary beam particles and the ejectiles after the secondary target. For the γ rays emitted by the fast moving fragments accurate Doppler correction was performed. From the obtained γ spectra of 39 Si displayed in Figure 1, two strong γ transitions at 163 and 397 keV as well as weaker ones at 303, 657, 906, 1143 and 1551 keV have been identified. γγ coincidences were obtained in 39 Si after having added all data from the various reaction channels giving rise to 39 Si. Analysing these data the 163 keV transition was found to be in coincidence with the 657, 1143 and 1551 keV ones, but not with the 397 keV transition. The two lines of the 303+397 keV doublet are in mutual coincidence, and one or both of them are found in coincidence with the 906 keV transition.

  17. Mass measurement and structure studies of neutron-rich isotopes of Zn, Ni, Fe

    International Nuclear Information System (INIS)

    Dessagne, P.

    1982-01-01

    With the Orsay MP Tandem, the reaction ( 14 C, 16 O) on 58 - 60 - 62 - 64 Ni, 64 - 66 - 68 - 70 Zn, 74 - 76 Ge and 82 Se targets, and the reaction ( 14 C, 15 O) on 60 - 62 - 64 Ni, 68 - 70 Zn, 76 Ge targets, have been investigated at 72 MeV bombarding energy. The mass excess of neutron rich nuclei: 63 Fe (-55.19+-.06MeV), 69 Ni(-60.14+-.06 MeV), 75 Zn(.62.7+-08 MeV) have been measured for the first time, and those of 62 Fe, 68 Ni, 74 Zn, 80 Ge have been remeasured. A new equipment has been designed in order to perform measurements at zero degree. From the angular distribution around 0 0 for the 70 Zn( 14 C, 16 O) reaction, the first state of 68 Ni observed for the first time (1.77 MeV +- .04 MeV) has been shown to be a 0 + . This result establishes a new case of 2 1+ - 0 2+ inversion. The systematics of the ( 14 C, 16 O) measurements on the even Ni and Zn isotopes have shown a different behaviour with two series. For the Ni → Fe (g.s.) transitions, the ratio σsub(exp)/σsub(DWBA) increases by a factor of four when the neutron number varies from 30 to 36. Whereas for the Zn → Ni (gs) transitions this ratio remains constant for the first three isotopes and decrease by a factor of two when N=40. For the Ni → Fe transitions, axial and spherical symmetries have been used. In agreement with the shell model no change are found with the spherical symmetry. For the axial symmetry a variation is observed but strongly dapendant of the sub-shell. Hence no clear conclusion can be deduced for the cross section estimate. For the Zn → Ni transitions, the spherical symmetry has been used. One configuration prevails, leading to a qualitative agreement with the experimental results [fr

  18. Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Rahaman A.

    2014-03-01

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

  19. 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

  20. Uranium and thorium cycles for sodium fast reactors: Neutronic aspects and associated wastes

    International Nuclear Information System (INIS)

    Brizi, J.

    2010-10-01

    Sodium fast reactors (SFR-Na) with uranium 238/plutonium 239(U/Pu) cycle, its technical feasibility has already proven, allow to overcome the problem of natural uranium resources in achieving the regeneration of the fuel fissile element. In addition, a waste management can be performed to reduce the radiotoxicity of actinides produced by the reactor in transmuting the AM in the core (homogeneous transmutation). Another alternative to minimize waste is to use another couple fertile-fissile: the thorium 232 and the uranium 233 (Th/U). The comparison is performed on neutronic and safety aspects and on waste production, in using an evolutive Monte Carlo. Although one does not disclose real clear advantages concerning the radiotoxicity of wastes for a particular cycle, the Th/U cycle reduces the radiotoxicity during periods when it is the highest. The homogeneous transmutation minimizes significantly for both cycles, radiotoxicity of wastes, with different factors depending on the considered time period. However, it is done to the detriment of an important increase of AM in the core. If we consider the nuclear stop, the inventory of the reactor core becomes a waste. The gain provided by the transmutation, taking into account both the core and accumulated waste radio-toxicities, will be quantified, and shows the transmutation does not provide a significant gain if the burning of main fissile elements is not considered when the nuclear is stopped. (author)

  1. Interactions Between Flavonoid-Rich Extracts and Sodium Caseinate Modulate Protein Functionality and Flavonoid Bioaccessibility in Model Food Systems.

    Science.gov (United States)

    Elegbede, Jennifer L; Li, Min; Jones, Owen G; Campanella, Osvaldo H; Ferruzzi, Mario G

    2018-05-01

    With growing interest in formulating new food products with added protein and flavonoid-rich ingredients for health benefits, direct interactions between these ingredient classes becomes critical in so much as they may impact protein functionality, product quality, and flavonoids bioavailability. In this study, sodium caseinate (SCN)-based model products (foams and emulsions) were formulated with grape seed extract (GSE, rich in galloylated flavonoids) and green tea extract (GTE, rich in nongalloylated flavonoids), respectively, to assess changes in functional properties of SCN and impacts on flavonoid bioaccessibility. Experiments with pure flavonoids suggested that galloylated flavonoids reduced air-water interfacial tension of 0.01% SCN dispersions more significantly than nongalloylated flavonoids at high concentrations (>50 μg/mL). This observation was supported by changes in stability of 5% SCN foam, which showed that foam stability was increased at high levels of GSE (≥50 μg/mL, P < 0.05) but was not affected by GTE. However, flavonoid extracts had modest effects on SCN emulsion. In addition, galloylated flavonoids had higher bioaccessibility in both SCN foam and emulsion. These results suggest that SCN-flavonoid binding interactions can modulate protein functionality leading to difference in performance and flavonoid bioaccessibility of protein-based products. As information on the beneficial health effects of flavonoids expands, it is likely that usage of these ingredients in consumer foods will increase. However, the necessary levels to provide such benefits may exceed those that begin to impact functionality of the macronutrients such as proteins. Flavonoid inclusion within protein matrices may modulate protein functionality in a food system and modify critical consumer traits or delivery of these beneficial plant-derived components. The product matrices utilized in this study offer relevant model systems to evaluate how fortification with flavonoid-rich

  2. 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.)

  3. 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.

  4. The sodium coolant

    International Nuclear Information System (INIS)

    Rodriguez, G.

    2004-01-01

    The sodium is the best appropriate coolant for the fast neutrons reactors technology. Thus the fast neutrons reactors development is intimately bound to the sodium technology. This document presents the sodium as a coolant point of view: atomic structure and characteristics, sodium impacts on the fast neutron reactors technology, chemical properties of the sodium and the consequences, quality control in a nuclear reactor, sodium treatment. (A.L.B.)

  5. Compact DD generator based in vivo neutron activation analysis (IVNAA) system to determine sodium concentrations in human bone.

    Science.gov (United States)

    Coyne, Mychaela Dawn; Neumann, Colby R; Zhang, Xinxin; Byrne, Patrick; Liu, Yingzi; Weaver, Connie M; Nie, Linda Huiling

    2018-04-16

    This study presents the development of a non-invasive method for monitoring Na in human bone. Many diseases, such as hypertension and osteoporosis, are closely associated with sodium (Na) retention in the human body. Na retention is generally evaluated by calculating the difference between dietary intake and excretion. There is currently no method to directly quantify Na retained in the body. Bone is a storage for many elements, including Na, which renders bone Na an ideal biomarker to study Na metabolism and retention. Approach: A customized compact deuterium-deuterium (DD) neutron generator was used to produce neutrons for in vivo neutron activation analysis (IVNAA), with a moderator/ reflector/ shielding assembly optimized for human hand irradiation in order to maximize the thermal neutron flux inside the irradiation cave and to limit radiation exposure to the hand and the whole body. Main Results: The experimental results show that the system is able to detect sodium levels in the bone as low as 12 g Na/g dry bone with an effective dose to the body of about 27 μSv. The simulation results agree with the numbers estimated from the experiment. Significance: This is expected to be a feasible method for measuring the change of Na in bone. The low detection limit indicates this will be a useful system to study the association between Na retention and related diseases. © 2018 Institute of Physics and Engineering in Medicine.

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

    Science.gov (United States)

    Patel, Zena

    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 and identified. The excited states of nuclei are studied by delayed isomeric or beta-delayed gamma-ray spectroscopy. New K isomers were found in Sm (Z=62), Eu (Z=63), and Gd (Z=64) isotopes. The key results are discussed here. Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time. The K-isomeric states in 166Gd and 164Sm are due to 2-quasiparticle configurations. Based on the decay patterns and potential energy surface calculations, including beta6 deformation, both isomers are assigned a (6-) spin-parity. The half-lives of the isomeric states have been measured to be 950(60)ns and 600(140)ns for 166Gd and 164Sm respectively. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground state band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100) respectively, presents evidence for the predicted deformed shell closure at N=100. A 4-quasiparticle isomeric state has been discovered in 160Sm: the lightest deformed nucleus with a 4-quasiparticle isomer to date. The isomeric state is assigned an (11+) spin-parity with a measured half-life of 1.8(4)us. The (11+) isomeric state decays into a rotational band structure, based on a (6-) v5/2-[523] ⊗ v7/2+[633] bandhead, determined from the extracted gK-gR values. Potential energy surface and blocked BCS calculations were performed in the deformed midshell region

  7. Lifetimes in neutron-rich Nd isotopes measured by Doppler profile method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Lister, C.J.; Morss, L.R. [and others

    1995-08-01

    Lifetimes of the rotational levels in neutron-rich even-even Nd isotopes were deduced from the analysis of the Doppler broadened line shapes. The experiment was performed at Daresbury with the Eurogam array, which at that time consisted of 45 Compton-suppressed Ge detectors and 5 Low-Energy Photon Spectrometers. The source was in the form of a 7-mm pellet which was prepared by mixing 5-mg; {sup 248}Cm and 65-mg KCl and pressing it under high pressure. Events for which three or more detectors fired were used to construct a cubic data array whose axes represented the {gamma}-ray energies and the contents of each channel the number of events with that particular combination of {gamma}-ray energies. From this cubic array, one-dimensional spectra were generated by placing gates on peaks on the other two axes. Gamma-ray spectra of even-even Nd isotopes were obtained by gating on the transitions in the complimentary Kr fragments. The gamma peaks de-exciting states with I {>=} 12 h were found to be broader than the instrumental line width due to the Doppler effect. The line shapes of they-ray peaks were fitted separately with a simple model for the feeding of the states and assuming a rotational band with constant intrinsic quadruple moment and these are shown in Fig. I-27. The quadrupole moments thus determined were found to be in good agreement with the quadrupole moments measured previously for lower spin states. Because of the success of this technique for the Nd isotopes, we intend to apply this technique to the new larger data set collected with the Eurogam II array. The results of this study were published.

  8. sodium

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les initiatives de réduction de la consommation de sel qui visent l'ensemble de la population et qui ciblent la teneur en sodium des aliments et sensibilisent les consommateurs sont susceptibles de réduire la consommation de sel dans toutes les couches de la population et d'améliorer la santé cardiovasculaire. Ce projet a ...

  9. The impact of the tensor interaction on the β-delayed neutron emission of the neutron-rich Ni isotopes

    Directory of Open Access Journals (Sweden)

    Sushenok E.O.

    2018-01-01

    Full Text Available The neutron emission of the β-decay of 74;76;78;80Ni are studied within the quasiparticle random phase approximation with the Skyrme interaction. The coupling between one- and two-phonon terms in the wave functions of the low-energy 1+ states of the daughter nuclei is taken into account. It is shown that the strength decrease of the neutronproton tensor interaction leads to the increase of the half-life and the neutron-emission probability.

  10. Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei

    Directory of Open Access Journals (Sweden)

    Tolosa-Delgado A.

    2017-01-01

    Full Text Available The commissioning of a new setup for β-delayed neutron measurements was carried out successfully in November-2016, at the RIKEN Nishina Center in Japan. The β-decay half-lives and Pn branching ratios of several isotopes in the 78Ni region were measured. Details of the experimental setup and the first results are given.

  11. Safeguards Considerations for the Design of a Future Fast Neutron Sodium Cooled Reactor

    International Nuclear Information System (INIS)

    Cazalet, J.; Raymond, P.; Masson, M.; Saturnin, A.

    2015-01-01

    Incorporating safeguards at an early stage of a reactor design is a way to increase the effectiveness and efficiency of safeguards measures minimizing the possibilities of misuse of the plant or nuclear material diversion. It also reduces the impact on the construction and operation cost. At the preliminary phase, the design will integrate: confinement, containment, surveillance features and non-destructive assay equipment. Taking into account these requirements will help the operator in the approval of the plant at the design phase by national and international authorities in charge of Nuclear Material accounting and safeguards. A large amount of work has been made by the GEN IV International Forum to assess the proliferation resistance of nuclear systems. The IAEA has developed guidelines on ''Safeguards by design'' describing reference requirements for future nuclear facilities. Based on these studies, this communication details implementation of safeguards in the design of a sodium cooled fast neutron reactor (SFR) currently studied in France. Specificities are the use of MOX fuel with high concentration of plutonium and the potential capacity of breeding. A great attention should be paid to avoid diversion of nuclear material contained in fresh or irradiated fuel. Scenarios of reactor misuse are analyzed. The identification of diversion pathways and requirements for nuclear material accountancy, leads to an approach of safeguards, specific to SFR: Material Balance Areas (MBA) and some key measurement points (KMP) are characterized. Specific instrumentation assay helping in the identification and/or characterization of fuel elements and the inventory of nuclear material is described. As concerns the fuel cycle, the safeguards of the reprocessing unit will be progressively increased through the development of materials monitoring and the implementation of these measures at strategic locations of buildings, thus providing real-time information

  12. The effect of the scalar-isovector meson field on hyperon-rich neutron star matter

    International Nuclear Information System (INIS)

    Mi, Aijun; Zuo, Wei; Li, Ang

    2008-01-01

    We investigate the effect of the scalar-isovector δ-meson field on the equation of state (EOS) and composition of hyperonic neutron star matter, and the properties of hyperonic neutron stars within the framework of the relativistic mean field theory. The influence of the δ-field turns out to be quite different and generally weaker for hyperonic neutron star matter as compared to that for npeμ neutron star matter. We find that inclusion of the δ-field enhances the strangeness content slightly and consequently moderately softens the EOS of neutron star matter in its hyperonic phase. As for the composition of hyperonic star matter, the effect of the δ-field is shown to shift the onset of the negatively-charged (positively-charged) hyperons to slightly lower (higher) densities and to enhance (reduce) their abundances. The influence of the δ-field on the maximum mass of hyperonic neutron stars is found to be fairly weak, whereas inclusion of the δ-field turns out to enhance sizably both the radii and the moments of inertia of neutron stars with given masses. It is also shown that the effects of the δ-field on the properties of hyperonic neutron stars remain similar in the case of switching off the Σ hyperons. (author)

  13. Fe and N diffusion in nitrogen-rich FeN measured using neutron ...

    Indian Academy of Sciences (India)

    E-mail: mgupta@csr.ernet.in. Abstract. Grazing incidence neutron reflectometry provides an opportunity to measure the depth profile of a thin film sample with a resolution <1 nm, in a non-destructive way. In this way the diffusion across the interfaces can also be measured. In addition, neutrons have contrast among the ...

  14. Fluorine and Sodium in C-rich Low-metallicity Stars

    Science.gov (United States)

    Lucatello, Sara; Masseron, Thomas; Johnson, Jennifer A.; Pignatari, Marco; Herwig, Falk

    2011-03-01

    We present the N, O, F, and Na abundance and 12C/13C isotopic ratio measurements or upper limits for a sample of 10 C-rich, metal-poor giant stars: 8 enhanced in s-process (CEMP-s) elements and 2 poor in n-capture elements (CEMP-no). The abundances are derived from IR, K-band, high-resolution CRIRES@VLT obtained spectra. The metallicity of our sample ranges from [Fe/H] = -3.4 to -1.3. F abundance could be measured only in two CEMP-s stars. With [F/Fe] = 0.64, one is mildly F-overabundant, while the other is F-rich, at [F/Fe] = 1.44. For the remaining eight objects, including both CEMP-no stars in our sample, only upper limits on F abundance could be placed. Our measurements and upper limits show that there is a spread in the [F/C+N] ratio in CEMP-s stars as predicted by theory. Predictions from nucleosynthetic models for low-mass, low-metallicity asymptotic giant branch (AGB) stars account for the derived F abundances, while the upper limits on F content derived for most of the stars are lower than the predicted values. The measured Na content is accounted for by AGB models in the 1.25-1.75 M sun range, confirming that the stars responsible for the peculiar abundance pattern observed in CEMP-s stars are low-mass, low-metallicity AGB stars in agreement with the most accepted astrophysical scenario. We conclude that the mechanism of F production in current state-of-the-art low-metallicity low-mass AGB models needs further scrutiny and that F measurements in a larger number of metal-poor stars are needed to better constrain the models. Based on observations made with ESO Telescopes at Paranal Observatories under program ID 080.D-0606A. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation.

  15. A neutronics study for improving the safety and performance parameters of a 3600 MWth Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    Sun, Kaichao; Krepel, Jiri; Mikityuk, Konstantin; Chawla, Rakesh

    2013-01-01

    Highlights: ► The potential for neutronics design optimization is assessed for a large SFR core. ► Both beginning-of-life and equilibrium fuel cycle conditions are considered. ► The sodium void effect is decomposed via a neutron balance based methodology. ► The optimized core options adopt an appropriate sodium plenum design to reduce the void effect. ► The introduction of moderator pins is considered for enhancing the Doppler effect. - Abstract: The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many performance advantages, but has one dominating neutronics drawback – a positive sodium void reactivity. The starting point for the present study is an SFR core design considered in the Collaborative Project on the European Sodium-cooled Fast Reactor (CP-ESFR). The aim is to analyze, for this reference core, four safety and performance parameters from the viewpoint of four different optimization options, and to propose possible optimized core designs. In doing so, the study focuses not only on the beginning-of-life state of the core, but also on the beginning of equilibrium closed fuel cycle. The four studied optimization options are: (a) introducing an upper sodium plenum and boron layer, (b) varying the core height-to-diameter (H/D) ratio, (c) introducing moderator pins into the fuel assembly, and (d) modifying the initial plutonium content. The sensitivity of the void reactivity, Doppler constant, nominal reactivity and breeding gain has been evaluated. In particular, the void reactivity, which is the most crucial safety parameter for the SFR, has been decomposed into its reaction-wise, isotope-wise and energy-group-wise components using a methodology based on the neutron balance equation. Extended voiding in the upper sodium plenum region – in conjunction with the effect of a boron layer introduced above the plenum – is found to be particularly effective in the void effect reduction while, at the same time

  16. Universal odd-even staggering in isotopic fragmentation and spallation cross sections of neutron-rich fragments

    Science.gov (United States)

    Mei, B.; Tu, X. L.; Wang, M.

    2018-04-01

    An evident odd-even staggering (OES) in fragment cross sections has been experimentally observed in many fragmentation and spallation reactions. However, quantitative comparisons of this OES effect in different reaction systems are still scarce for neutron-rich nuclei near the neutron drip line. By employing a third-order difference formula, the magnitudes of this OES in extensive experimental cross sections are systematically investigated for many neutron-rich nuclei with (N -Z ) from 1 to 23 over a broad range of atomic numbers (Z ≈3 -50 ). A comparison of these magnitude values extracted from fragment cross sections measured in different fragmentation and spallation reactions with a large variety of projectile-target combinations over a wide energy range reveals that the OES magnitude is almost independent of the projectile-target combinations and the projectile energy. The weighted average of these OES magnitudes derived from cross sections accurately measured in different reaction systems is adopted as the evaluation value of the OES magnitude. These evaluated OES magnitudes are recommended to be used in fragmentation and spallation models to improve their predictions for fragment cross sections.

  17. Study of ground-state configuration of neutron-rich aluminium isotopes through electromagnetic excitation

    International Nuclear Information System (INIS)

    Chakraborty, S.; Datta Pramanik, U.; Chatterjee, S.

    2013-01-01

    The region of the nuclear chart around neutron magic number, N∼20 and proton number (Z), 10≤ Z≤12 is known as the Island of Inversion. The valance neutron(s) of these nuclei, even in their ground state, are most likely occupying the upper pf orbitals which are normally lying above sd orbitals, N∼20 shell closure. Nuclei like 34,35 Al are lying at the boundary of this Island of Inversion. Little experimental information about their ground state configuration are available in literature

  18. Extending FEAST-METAL for analysis of low content minor actinide bearing and zirconium rich metallic fuels for sodium fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Karahan, Aydin, E-mail: karahan@mit.edu [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge MA 24-204 (United States)

    2011-07-15

    Computational models in FEAST-METAL fuel behaviour code have been upgraded to simulate minor actinide bearing zirconium rich metallic fuels for use in sodium fast reactors. Increasing the zirconium content to 20-40 wt.% causes significant changes in fuel slug microstructure affecting thermal, mechanical, chemical, and fission gas behaviour. Inclusion of zirconium rich phase reduces the fission gas swelling rate significantly in early irradiation. Above the threshold fission gas swelling, formation of micro-cracks, and open pores increase material compliancy enhance diffusivity, leading to rapid fuel gas swelling, interconnected porosity development and release of the fission gases and helium. Production and release of helium was modelled empirically as a function of americium content and fission gas production, consistent with previous Idaho National Laboratory studies. Predicted fuel constituent redistribution is much smaller compared to typical U-Pu-10Zr fuel operated at EBR-II. Material properties such as fuel thermal conductivity, modulus of elasticity, and thermal expansion coefficient have been approximated using the available database. Creep rate and fission gas diffusivity of high zirconium fuel is lowered by an order of magnitude with respect to the reference low zirconium fuel based on limited database and in order to match experimental observations. The new code is benchmarked against the AFC-1F fuel assembly post irradiation examination results. Satisfactory match was obtained for fission gas release and swelling behaviour. Finally, the study considers a comparison of fuel behaviour between high zirconium content minor actinide bearing fuel and typical U-15Pu-6Zr fuel pins with 75% smear density. The new fuel has much higher fissile content, allowing for operating at lower neutron flux level compared to fuel with lower fissile density. This feature allows the designer to reach a much higher burnup before reaching the cladding dose limit. On the other

  19. Extending FEAST-METAL for analysis of low content minor actinide bearing and zirconium rich metallic fuels for sodium fast reactors

    Science.gov (United States)

    Karahan, Aydın

    2011-07-01

    Computational models in FEAST-METAL fuel behaviour code have been upgraded to simulate minor actinide bearing zirconium rich metallic fuels for use in sodium fast reactors. Increasing the zirconium content to 20-40 wt.% causes significant changes in fuel slug microstructure affecting thermal, mechanical, chemical, and fission gas behaviour. Inclusion of zirconium rich phase reduces the fission gas swelling rate significantly in early irradiation. Above the threshold fission gas swelling, formation of micro-cracks, and open pores increase material compliancy enhance diffusivity, leading to rapid fuel gas swelling, interconnected porosity development and release of the fission gases and helium. Production and release of helium was modelled empirically as a function of americium content and fission gas production, consistent with previous Idaho National Laboratory studies. Predicted fuel constituent redistribution is much smaller compared to typical U-Pu-10Zr fuel operated at EBR-II. Material properties such as fuel thermal conductivity, modulus of elasticity, and thermal expansion coefficient have been approximated using the available database. Creep rate and fission gas diffusivity of high zirconium fuel is lowered by an order of magnitude with respect to the reference low zirconium fuel based on limited database and in order to match experimental observations. The new code is benchmarked against the AFC-1F fuel assembly post irradiation examination results. Satisfactory match was obtained for fission gas release and swelling behaviour. Finally, the study considers a comparison of fuel behaviour between high zirconium content minor actinide bearing fuel and typical U-15Pu-6Zr fuel pins with 75% smear density. The new fuel has much higher fissile content, allowing for operating at lower neutron flux level compared to fuel with lower fissile density. This feature allows the designer to reach a much higher burnup before reaching the cladding dose limit. On the other

  20. Extending FEAST-METAL for analysis of low content minor actinide bearing and zirconium rich metallic fuels for sodium fast reactors

    International Nuclear Information System (INIS)

    Karahan, Aydin

    2011-01-01

    Computational models in FEAST-METAL fuel behaviour code have been upgraded to simulate minor actinide bearing zirconium rich metallic fuels for use in sodium fast reactors. Increasing the zirconium content to 20-40 wt.% causes significant changes in fuel slug microstructure affecting thermal, mechanical, chemical, and fission gas behaviour. Inclusion of zirconium rich phase reduces the fission gas swelling rate significantly in early irradiation. Above the threshold fission gas swelling, formation of micro-cracks, and open pores increase material compliancy enhance diffusivity, leading to rapid fuel gas swelling, interconnected porosity development and release of the fission gases and helium. Production and release of helium was modelled empirically as a function of americium content and fission gas production, consistent with previous Idaho National Laboratory studies. Predicted fuel constituent redistribution is much smaller compared to typical U-Pu-10Zr fuel operated at EBR-II. Material properties such as fuel thermal conductivity, modulus of elasticity, and thermal expansion coefficient have been approximated using the available database. Creep rate and fission gas diffusivity of high zirconium fuel is lowered by an order of magnitude with respect to the reference low zirconium fuel based on limited database and in order to match experimental observations. The new code is benchmarked against the AFC-1F fuel assembly post irradiation examination results. Satisfactory match was obtained for fission gas release and swelling behaviour. Finally, the study considers a comparison of fuel behaviour between high zirconium content minor actinide bearing fuel and typical U-15Pu-6Zr fuel pins with 75% smear density. The new fuel has much higher fissile content, allowing for operating at lower neutron flux level compared to fuel with lower fissile density. This feature allows the designer to reach a much higher burnup before reaching the cladding dose limit. On the other

  1. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Clément E.

    2013-12-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  2. 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.

  3. The study of the structural properties of very low viscosity sodium alginate by small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Badita, C. R., E-mail: ramona@tandem.nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); University of Bucharest, Faculty of Physics, Atomiştilor 405, CP MG - 11, RO – 077125, Bucharest-Magurele (Romania); Aranghel, D., E-mail: daranghe@nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Extreme Light Intrastructure Nuclear Physics (ELI-NP), Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest (Romania); Radulescu, A. [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science, 85747 Garching (Germany); Anitas, E. M. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Reactorului 30, RO-077125, POB-MG6, Magurele-Bucharest, Romania, ramona@tandem.nipne.ro, daranghe@nipne.ro (Romania); Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)

    2016-03-25

    Sodium alginate is a linear polymer extract from brown algae and it is used in the biomedical, food, cosmetics and pharmaceutical industries as solution property modifiers and gelling agents. But despite the extensive studies of the alginate gelation process, still some fundamental questions remain unresolved. The fractal behavior of very low viscosity sodium alginate solutions and their influence on the critical gelation of alginate induced by Ca{sup 2+} ions were investigated using Small-Angle Neutron Scattering (SANS) measurements. SANS data are interpreted using both standard linear plots and the Beaucage model. The scattering intensity is dependent by alginate concentration and Ca{sup 2+} concentration. From a critical concentration of 1.0 % w/w our polymer swelled forming spherical structures with rough surfaces. Also the addition of the salt induces the collapse and the appearance of the aggregation and clusters formation.

  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. 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...

  6. Nuclear spectroscopy of neutron rich A = 147 nuclides: decay of 147Cs, 147Ba and 147La

    International Nuclear Information System (INIS)

    Shmid, M.; Chu, Y.Y.; Gowdy, G.M.

    1981-01-01

    A study of the beta decay of neutron rich nuclides of the A = 147 chain was carried out at the TRISTAN isotope separator. Half lives of 14 'Cs, 147 Ba and 147 La were measured. Six gamma lines are assigned to 147 Cs decay. A decay scheme for 147 Ba with levels up to 2 MeV is proposed for the first time. A partial decay scheme for 147 La is proposed, which confirms the previously existing one, with five new levels added from the present work

  7. 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)

  8. Hyperfine structure and isotope shift of the neutron-rich barium isotopes 139-146Ba and 148Ba

    International Nuclear Information System (INIS)

    Wendt, K.; Ahmad, S.A.; Klempt, W.; Neugart, R.; Otten, E.W.

    1988-01-01

    The hyperfine structure and isotope shift in the 6s 2 S 1/2 -6p 2 P 3/2 line of Ba II (455.4 nm) have been measured by collinear fast-beam laser spectroscopy for the neutron-rich isotopes 139-146 Ba and 148 Ba. Nuclear moments and mean square charge radii of these isotopes have been recalculated. The isotope shift of the isotope 148 Ba (T 1/2 = 0.64 s) could be studied for the first time, yielding δ 2 > 138,148 = 1.245(3) fm 2 . (orig.)

  9. 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.

  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. Sensitivity of the moment of inertia of neutron stars to the equation of state of neutron-rich matter

    International Nuclear Information System (INIS)

    Fattoyev, F. J.; Piekarewicz, J.

    2010-01-01

    The sensitivity of the stellar moment of inertia to the neutron-star matter equation of state is examined using accurately calibrated relativistic mean-field models. We probe this sensitivity by tuning both the density dependence of the symmetry energy and the high-density component of the equation of state, properties that are at present poorly constrained by existing laboratory data. Particularly attractive is the study of the fraction of the moment of inertia contained in the solid crust. Analytic treatments of the crustal moment of inertia reveal a high sensitivity to the transition pressure at the core-crust interface. This may suggest the existence of a strong correlation between the density dependence of the symmetry energy and the crustal moment of inertia. However, no correlation was found. We conclude that constraining the density dependence of the symmetry energy - through, for example, the measurement of the neutron skin thickness in 208 Pb - will place no significant bound on either the transition pressure or the crustal moment of inertia.

  12. Digestion of Alumina from Non-Magnetic Material Obtained from Magnetic Separation of Reduced Iron-Rich Diasporic Bauxite with Sodium Salts

    Directory of Open Access Journals (Sweden)

    Guanghui Li

    2016-11-01

    Full Text Available Recovery of iron from iron-rich diasporic bauxite ore via reductive roasting followed by magnetic separation has been explored recently. However, the efficiency of alumina extraction in the non-magnetic materials is absent. In this paper, a further study on the digestion of alumina by the Bayer process from non-magnetic material obtained after magnetic separation of reduced iron-rich diasporic bauxite with sodium salts was investigated. The results indicate that the addition of sodium salts can destroy the original occurrences of iron-, aluminum- and silicon-containing minerals of bauxite ore during reductive roasting. Meanwhile, the reactions of sodium salts with complex aluminum- and silicon-bearing phases generate diaoyudaoite and sodium aluminosilicate. The separation of iron via reductive roasting of bauxite ore with sodium salts followed by magnetic separation improves alumina digestion in the Bayer process. When the alumina-bearing material in bauxite ore is converted into non-magnetic material, the digestion temperature decreases significantly from 280 °C to 240 °C with a nearly 99% relative digestion ratio of alumina.

  13. Study of the structure of light neutron rich nucleus with the Tonnerre array

    International Nuclear Information System (INIS)

    Pietri, St.

    2003-06-01

    This work concern the technical development made on the multidetector TONNERRE and the study of the 34 Si nucleus by a complete beta-neutron-gamma spectroscopy. In the first part various tests performed on modules of the detector in the 'Centre d'Etude de Bruyere le Chatel' are presented. A modification of the embassies of the photomultipliers tubes allows to gain more than 50% in the neutron efficiency and to obtain a threshold lower than 300 keV for the neutron energy. A complete C++ simulation of the neutron propagation in the array was carried out. It explains that the slow component of the light output of the scintillator may be responsible of the shape of the time-of-flight spectrum. The second part of these report presents the experiment devoted to the study of the structure of the 34 Si from the beta decay of the 34 Al. It was performed at the GANIL facility using the TONNERRE array and germanium of ENOGAM. The 34 Al was produced by projectile fragmentation of a 36 S beam of 50 MeV/A in a target of 9 Be. A complete beta scheme of the 34 Al is proposed. Eight neutron lines following the 34 Al decay were observed for the first time. Finally we suggest that a monopolar transition could occur in the 34 Si nucleus signing a O + 2 state at 2133 keV. (author)

  14. 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 sneutron-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).

  15. Structure of neutron-rich isotopes of boron and carbon at the limits of stability

    International Nuclear Information System (INIS)

    Leblond, Sylvain

    2015-01-01

    The unbound nuclei 18 B and 21 C have been studied in an experiment undertaken at the RIBF-RIKEN using the recently commissioned SAMURAI spectrometer and NEBULA neutron array. The two systems were probed using single-neutron and single and two-proton knockout from secondary beams of 22 C, 22 N, et 23 O respectively in the case of 21 C and 19 B, 19 C and 20 N for 18 B. The invariant mass spectra were reconstructed from the momentum of the fragment ( 17 B, 20 C) and neutron. In order to interpret the results a complete simulation of the experimental setup was utilised. The analysis procedures as well as the calibrations were verified through a measurement of the well-known ground state of 16 B. In the case of 18 B three states were observed: an s-wave virtual state (as ≤ -50 fm), an l=2 resonance at E r =0.77 ± 0.09 MeV and an l=0 resonance at E r = 1.6 ± 0.6 MeV. These results suggest that the low-lying level structure of 18 B is governed by a competition between the neutron 2s 1/2 and 1d 5/2 configurations. In the case of 21 C resonances were observed at E r = 0.8 ± 0.15 MeV (l = 0) and E r = 1.5 ±0.1 MeV (l=2), a result which confirms predictions of an inversion of the 5/2 + and 1/2 + levels. Finally an analysis of the momentum distributions for 18 B and 21 C produced in single-neutron knockout was carried out. The results indicate that the valence neutrons 19 B and 22 C are in mixed (2s 1/2 ) 2 and (1d 5/2 ) 2 configurations. (author)

  16. High flux, beamed neutron sources employing deuteron-rich ion beams from D2O-ice layered targets

    Science.gov (United States)

    Alejo, A.; Krygier, A. G.; Ahmed, H.; Morrison, J. T.; Clarke, R. J.; Fuchs, J.; Green, A.; Green, J. S.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.; Kar, S.

    2017-06-01

    A forwardly-peaked bright neutron source was produced using a laser-driven, deuteron-rich ion beam in a pitcher-catcher scenario. A proton-free ion source was produced via target normal sheath acceleration from Au foils having a thin layer of D2O ice at the rear side, irradiated by sub-petawatt laser pulses (˜200 J, ˜750 fs) at peak intensity ˜ 2× {10}20 {{W}} {{cm}}-2. The neutrons were preferentially produced in a beam of ˜70° FWHM cone along the ion beam forward direction, with maximum energy up to ˜40 MeV and a peak flux along the axis ˜ 2× {10}9 {{n}} {{sr}}-1 for neutron energy above 2.5 MeV. The experimental data is in good agreement with the simulations carried out for the d(d,n)3He reaction using the deuteron beam produced by the ice-layered target.

  17. The fast neutrons reactors, the sodium, the fuel cycle: evaluation of the knowledge, innovation potential and forecast; Les reacteurs a neutrons rapides, le sodium, le cycle du combustible: bilan de l'acquis, potentiel d'innovation et perspectives d'avenir

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, J

    2002-07-01

    This document presents the study, the design and the construction of fast neutrons reactors, cooled with sodium. From this evaluation, it details the innovation possibilities of this sector in the sustainable development context of the nuclear energy. Chapter one presents the physical and physico-chemical properties of the sodium. Chapter two analyzes the properties of the fast cores and the sodium advantages. Chapter three analyzes the great contribution of the EFR project. Chapter four takes stock on the innovation possibilities. And before the conclusion, chapter five shows that the fast neutrons reactors allow the electric power production in agreement with a sustainable development. (A.L.B.)

  18. Results of neutron propagation in steel sodium mixtures with various source spectra on Harmonie and Tapiro

    International Nuclear Information System (INIS)

    Calamand, D.; Desprets, A.; Rancurel, H.

    1977-01-01

    The first results of a joint CEA/CNEN neutron propagation program conducted on the source reactors HARMONIE and TAPIRO are presented. In both cases, a buffer zone representative of the blanket of a commercial fast power reactor is interposed between the source reactor and the medium in which neutron propagation is measured. This buffer zone provides a realistic source spectrum to be propagated. Experimental results are compared to older results obtained without the buffer zone. The effect of the source spectrum on neutron propagation is discussed, as well as the coherence of the results obtained with the two installations

  19. Deep-UV Raman spectroscopic analysis of structure and dissolution rates of silica-rich sodium borosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Pierce, Eric M.; Burton, Sarah D.; Bovaird, Chase C.

    2011-03-24

    As part of ongoing studies to evaluate the relationships between structural variations in silicate glasses and rates of glass dissolution in aqueous media, molecular structures present in sodium borosilicate glasses of composition Na2O.xB2O3.(3-x)SiO2, with x 1 (Na2O/B2O3 ratio 1), were analyzed using deep-UV Raman spectroscopy. The results were quantified in terms of the fraction of SiO4 tetrahedra with one non-bridging oxygen (Q3) and then correlated with Na2O and B2O3 content. Increasing Na2O was found to raise the fraction of Q3 units in the glasses systematically, in agreement with studies on related glasses, and, as long as the value of x was not too high, contribute to higher rates of dissolution in single pass flow-through testing. The finding was obtained across more than one series of silica-rich glasses prepared for independent dissolution studies. In contrast, dissolution rates were less strongly determined by the Q3 fraction when the value of x was near unity and appeared to grow larger upon further reduction of the Q3 fraction. The results were interpreted to indicate the increasingly important role of network hydrolysis in the glass dissolution mechanism as the BO4 tetrahedron replaces the Q3 unit as the charge-compensating structure for Na+ ions. Finally, the use of deep-UV Raman spectroscopy was found to be advantageous in studying finely powdered glasses in cases where visible Raman spectroscopy suffered from weak Raman scattering and fluorescence interference.

  20. Neutron diffraction investigations of the superionic conductors lithium sulfide and sodium sulfide

    International Nuclear Information System (INIS)

    Altorfer, F.

    1990-03-01

    Statics and dynamics of the superionic conductors lithium sulfide and sodium sulfide were investigated using the following experimental methods: elastic scattering on sodium sulfide powder in the temperature range 20 - 1000 C, elastic scattering on a lithium sulfide single crystal in the temperature range 20 - 700 C, inelastic scattering on a 7 Li 2 S single crystal at 10 K. 34 figs., 2 tabs., 10 refs

  1. Study of single particle properties of neutron-rich Na isotopes on the "shore of the island of inversion" by means of neutron-transfer reactions

    CERN Multimedia

    Reiter, P; Blazhev, A A; Riisager, K; Bastin, B; Tengborn, E A; Kruecken, R; Voulot, D; Jeppesen, H B; Hadinia, B; Gernhaeuser, R A; Fynbo, H O U; Georgiev, G P; Habs, D; Fraile prieto, L M; Chapman, R; Nilsson, T; Diriken, J V J; Jenkins, D G; Kroell, T; Leske, J; Huyse, M L; Patronis, N

    We aim at the investigation of single particle properties of neutron-rich Na isotopes around the "shore of the island of inversion". As first experiment of this programme, we propose to study excited states in the isotope $^{29}$Na by a one-neutron transfer reaction with a $^{28}$Na beam at 3 MeV/u obtained from REX-ISOLDE impinging on a CD$_{2}$-target. The $\\gamma$-rays will be detected by the MINIBALL array and the particles by the T-REX array of segmented Si detectors. The main physics aims are to extract from the relative spectroscopic factors information on the configurations contributing to the wave functions of the populated states and, secondly, to identify and characterize negative parity states whose excitation energies reflect directly the N= 28 gap in this region. The results will be compared to recent shell model calculations involving new residual interactions. This will shed new light on the evolution of single particle structure and help to understand the underlying physics relevant for the f...

  2. 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.

  3. Neutron scattering study of the magnetic correlations of iron rich Fe-Zr glasses

    International Nuclear Information System (INIS)

    Fernandez-Baca, J.A.; Rhyne, J.J.; Erwin, R.W.; Fish, G.E.

    1988-01-01

    Small angle neutron scattering (SANS) and polarized-beam spin rotation measurements show that amorphous Fe/sub 80/Zr/sub 10/ does not exhibit conventional long range ferromagnetic order below T/sub C/. The SANS measurements show the existence of two characteristic length scales; one provides evidence of relatively large spin clusters, while the other is characteristic of the spin dynamics. 4 refs., 3 figs

  4. Saturation of Deformation and Identical Bands in Very-Neutron Rich Sr Isotopes

    CERN Multimedia

    2002-01-01

    The present proposal aims at establishing nuclear properties in an isotopic chain showing unique features. These features include the saturation of ground state deformation at its onset and the existence of ground state identical bands in neighbouring nuclei with the same deformation. The measurements should help to elucidate the role played by the proton-neutron residual interaction between orbitals with large spatial overlap, i.e. $\\pi g _{9/2} \

  5. 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.

  6. Production of neutron-rich isotopes by cold fragmentation in the reaction 197Au + Be at 950 A MeV

    International Nuclear Information System (INIS)

    Benlliure, J.; Pereira, J.; Schmidt, K.H.; Cortina-Gil, D.; Enqvist, T.; Heinz, A.; Junghans, A.R.; Farget, F.; Taieb, J.

    1999-09-01

    The production cross sections and longitudinal-momentum distributions of very neutron-rich isotopes have been investigated in the fragmentation of a 950 A MeV 179 Au beam in a beryllium target. Seven new isotopes ( 193 Re, 194 Re, 191 W, 192 W, 189 Ta, 187 Hf and 188 Hf) and the five-proton-removal channel were observed for the first time. The reaction mechanism leading to the formation of these very neutron-rich isotopes is explained in terms of the cold-fragmentation process. An analytical model describing this reaction mechanism is presented. (orig.)

  7. $\\beta$-decay study of neutron-rich Tl, Pb, and Bi by means of the pulsed-release technique and resonant laser ionisation

    CERN Multimedia

    Lettry, J

    2002-01-01

    It is proposed to study new neutron-rich nuclei around the Z = 82 magic shell closure, with major relevance for understanding the evolution of nuclear structure at extreme isospin values. Following the IS354 experiment, $\\beta$-decay studies of neutron-rich thallium, lead and bismuth isotopes will be performed for 215 $\\leqslant$ A $\\leqslant$ 219. To this purpose the pulsed-release technique, which was pioneered at ISOLDE, will be optimised. It will be complemented with the higher element selectivity that can be obtained by the unique features of resonant laser ionisation, available at ISOLDE from the RILIS source.

  8. Benchmark for Neutronic Analysis of Sodium-cooled Fast Reactor Cores with Various Fuel Types and Core Sizes

    International Nuclear Information System (INIS)

    Stauff, N.E.; Kim, T.K.; Taiwo, T.A.; Buiron, L.; Rimpault, G.; Brun, E.; Lee, Y.K.; Pataki, I.; Kereszturi, A.; Tota, A.; Parisi, C.; Fridman, E.; Guilliard, N.; Kugo, T.; Sugino, K.; Uematsu, M.M.; Ponomarev, A.; Messaoudi, N.; Lin Tan, R.; Kozlowski, T.; Bernnat, W.; Blanchet, D.; Brun, E.; Buiron, L.; Fridman, E.; Guilliard, N.; Kereszturi, A.; Kim, T.K.; Kozlowski, T.; Kugo, T.; Lee, Y.K.; Lin Tan, R.; Messaoudi, N.; Parisi, C.; Pataki, I.; Ponomarev, A.; Rimpault, G.; Stauff, N.E.; Sugino, K.; Taiwo, T.A.; Tota, A.; Uematsu, M.M.; Monti, S.; Yamaji, A.; Nakahara, Y.; Gulliford, J.

    2016-01-01

    One of the foremost Generation IV International Forum (GIF) objectives is to design nuclear reactor cores that can passively avoid damage of the reactor when control rods fail to scram in response to postulated accident initiators (e.g. inadvertent reactivity insertion or loss of coolant flow). The analysis of such unprotected transients depends primarily on the physical properties of the fuel and the reactivity feedback coefficients of the core. Within the activities of the Working Party on Scientific Issues of Reactor Systems (WPRS), the Sodium Fast Reactor core Feed-back and Transient response (SFR-FT) Task Force was proposed to evaluate core performance characteristics of several Generation IV Sodium-cooled Fast Reactor (SFR) concepts. A set of four numerical benchmark cases was initially developed with different core sizes and fuel types in order to perform neutronic characterisation, evaluation of the feedback coefficients and transient calculations. Two 'large' SFR core designs were proposed by CEA: those generate 3 600 MW(th) and employ oxide and carbide fuel technologies. Two 'medium' SFR core designs proposed by ANL complete the set. These medium SFR cores generate 1 000 MW(th) and employ oxide and metallic fuel technologies. The present report summarises the results obtained by the WPRS for the neutronic characterisation benchmark exercise proposed. The benchmark definition is detailed in Chapter 2. Eleven institutions contributed to this benchmark: Argonne National Laboratory (ANL), Commissariat a l'energie atomique et aux energies alternatives (CEA of Cadarache), Commissariat a l'energie atomique et aux energies alternatives (CEA of Saclay), Centre for Energy Research (CER-EK), Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Nuclear Technology and Energy Systems (IKE), Japan Atomic Energy Agency (JAEA), Karlsruhe Institute of Technology (KIT

  9. Innovating analytical spectroscopies for the improvement of liquid sodium cooled fast neutron reactors safety

    International Nuclear Information System (INIS)

    Maury, C.

    2012-01-01

    In the context of the project of sodium fast reactor ASTRID, CEA is currently developing new analytical techniques to monitor the chemical purity of liquid sodium. Indeed, incidental situations occurring in the reactor, such as fuel clad failures, leakages in the steam generator or in the coolant pumps, and accelerated corrosion, might release several elements in the sodium. Analytical techniques based on laser ablation and emission spectroscopy are well suited for this application. They do not require any sample preparation, and can perform direct on-line analysis. Amongst them, Laser-Induced Breakdown Spectroscopy (LIBS) and Laser-Ablation coupled to Laser-Induced Fluorescence (LA-LIF) have been selected for this study. The objective of this work was to characterize the sensitivity of those two techniques for the detection of impurities in liquid sodium. Their limits of detection were calculated for model analytes using calibration lines. Then results were theoretically extrapolated to other analytes of interest. This study shows the feasibility of the detection of steel corrosion products in liquid sodium. However, the LIBS technique is more robust and easier to implement, and would therefore be more suited to nuclear conditions. (author) [fr

  10. 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

  11. Low-lying level structure of the neutron-rich nucleus {sup 109}Nb: A possible oblate-shape isomer

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H., E-mail: hiroshi@ribf.riken.j [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sumikama, T. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Nishimura, S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yoshinaga, K. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Li, Z. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Miyashita, Y. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Yamaguchi, K. [Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka (Japan); Baba, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Berryman, J.S. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Blasi, N. [INFN, Sezione di Milano, via Celoria 16, I-20133 Milano (Italy); Bracco, A.; Camera, F. [INFN, Sezione di Milano, via Celoria 16, I-20133 Milano (Italy); Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Chiba, J. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba (Japan); Doornenbal, P. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Go, S.; Hashimoto, T.; Hayakawa, S. [Center for Nuclear Study, University of Tokyo, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Hinke, C. [Physik Department, Technische Universitaet Muenchen, D-85748 Garching (Germany); Ideguchi, E. [Center for Nuclear Study, University of Tokyo, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Isobe, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2011-01-31

    The neutron-rich nuclei {sup 109}Nb and {sup 109}Zr have been populated using in-flight fission of a {sup 238}U beam at 345 MeV/nucleon at the RIBF facility. A T{sub 1/2}=150(30) ns isomer at 313 keV has been identified in {sup 109}Nb for the first time. The low-lying levels in {sup 109}Nb have been also populated following the {beta}-decay of {sup 109}Zr. Based on the difference in feeding pattern between the isomeric and {beta} decays, the decay scheme from the isomeric state in {sup 109}Nb was established. The observed hindrances of the electromagnetic transitions deexciting the isomeric state are discussed in terms of possible shape coexistence. Potential energy surface calculations for single-proton configurations predict the presence of low-lying oblate-deformed states in {sup 109}Nb.

  12. β decay half-live measurement of 22 very neutron-rich isotopes in the Ti-Ni region

    International Nuclear Information System (INIS)

    Czajkowski, S.; Ameil, F.; Armbruster, P.; Donzaud, C.; Geissel, H.; Kozhuharov, C.; Schwab, W.; Bernas, M.; Dessagne, P.; Miehe, C.; Grewe, A.; Hanelt, E.; Heinz, A.; Jong, M. de; Steinhaeuser, S.; Janas, Z.

    1997-01-01

    Very neutron-rich Ti to Ni isotopes were produced in fragmentation of a 500 MeV/u 86 Kr primary beam on a Be target, separated using the Fragment Separator at GSI, and implanted in a set of PIN-diodes where β-decay particles were detected. From time-correlations analysis the unknown β-decay half-life of 22 isotopes were determined. Their values are within 10 -1 s. The β decay spectrum of 70 Co is presented as resulting from an analysis of the first β particle detected after ion implantation in the same detector. Also are presented the example of 3 β decay chains for 65 Mn and 66 Mn. The identification of such chains was instrumental in reducing the influence of background noise in the time correlation analysis while it allows life-time determinations of high confidence

  13. Sodium, potassium and chloride status in Australian foods and diets using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fardy, J J; McOrist, G D; Farrar, Y J; Bowles, C J [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1994-12-31

    A study of the status of essential, toxic and trace elements in the foods and diets of Australian has been in progress for six years. Results for sodium, potassium and chloride levels are reported here. The average daily dietary intake of sodium and chloride exceeded the range of values recommended by the National Health and Medical Research Council for most population groups with grain and dairy products the main contributor to these high intakes. In contrast, the average daily intakes of potassium fell well within the recommended values for all age groups with intakes for adult females close to the recommended minimum figure. 9 refs., 1 tab., 2 figs.

  14. Sodium, potassium and chloride status in Australian foods and diets using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.; Bowles, C.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    A study of the status of essential, toxic and trace elements in the foods and diets of Australian has been in progress for six years. Results for sodium, potassium and chloride levels are reported here. The average daily dietary intake of sodium and chloride exceeded the range of values recommended by the National Health and Medical Research Council for most population groups with grain and dairy products the main contributor to these high intakes. In contrast, the average daily intakes of potassium fell well within the recommended values for all age groups with intakes for adult females close to the recommended minimum figure. 9 refs., 1 tab., 2 figs.

  15. 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

  16. 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.)

  17. Measurement of the magnetic moment of the 2$^{+}$ state in neutron-rich radioactive $^{72,74}$Zn using the transient field technique in inverse kinematics

    CERN Multimedia

    Kruecken, R; Speidel, K; Voulot, D; Neyens, G; Gernhaeuser, R A; Fraile prieto, L M; Leske, J

    We propose to measure the sign and magnitude of the g-factors of the first 2$^{+}$ states in radioactive neutron-rich $^{72,74}$Zn applying the transient field (TF) technique in inverse kinematics. The result of this experiment will allow to probe the $\

  18. Phenomenological study of nuclear structure of neutron-rich 88Rb isotope

    Science.gov (United States)

    Gupta, Surbhi; Gupta, Anuradha; Bharti, Arun

    2018-05-01

    A theoretical study of the nuclear structure of odd-odd 88Rb nucleus in the A ˜100 mass region is carried out by using the angular-momentum-projection technique implemented in the Projected Shell Model (PSM). The influence of the high-j orbitals, h11/2 for neutrons and g9/2 for protons on the structure of 88Rb isotope is investigated in the present case by assuming an axial symmetry in the deformed basis. For this isotope, PSM calculations are performed to obtain the yrast line and also the description of the formation of the yrast level structure from multi-quasi-particle configurations. The back-bending in moment of inertia and transition energies have also been calculated and compared with the experimental data.

  19. 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)

  20. 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)

  1. Decay of neutron-rich Mn nuclides and deformation of heavy Fe isotopes

    CERN Document Server

    Hannawald, M; Wöhr, A; Walters, W B; Kratz, K L; Fedosseev, V; Mishin, V I; Böhmer, W; Pfeiffer, B; Sebastian, V; Jading, Y; Köster, U; Lettry, Jacques; Ravn, H L

    1999-01-01

    The use of chemically selective laser ionization combined with beta-delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms Mn-61 up through 14-ms Mn-69. The measured half-lives are found to be significantly longer near N=40 than the values calculated with a QRPA shell model using ground-state deformations from the FRDM and ETFSI models. Gamma-ray singles and coincidence spectroscopy has been performed for Mn-64 and Mn-66 decays to levels of Fe-64 and Fe-66, revealing a significant drop in the energy of the first 2+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40.

  2. Role of nuclear couplings in the inelastic excitation of weakly-bound neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Dasso, C.H. [Niels Bohr Institute, Copenhagen (Denmark); Lenzi, S.M.; Vitturi, A. [Universita di Padova (Italy)

    1996-12-31

    Much effort is presently devoted to the study of nuclear systems far from the stability line. Particular emphasis has been placed in light systems such as {sup 11}Li, {sup 8}B and others, where the very small binding energy of the last particles causes their density distribution to extend considerably outside of the remaining nuclear core. Some of the properties associated with this feature are expected to characterize also heavier systems in the vicinity of the proton or neutron drip lines. It is by now well established that low-lying concentrations of multipole strength arise from pure configurations in which a peculiar matching between the wavelength of the continuum wavefunction of the particles and the range of the weakly-bound hole states occurs. To this end the authors consider the break-up of a weakly-bound system in a heavy-ion collision and focus attention in the inelastic excitation of the low-lying part of the continuum. They make use of the fact that previous investigations have shown that the multipole response in this region is not of a collective nature and describe their excited states as pure particle-hole configurations. Since the relevant parameter determining the strength distributions is the binding energy of the last bound orbital they find it most convenient to use single-particle wavefunctions generated by a sperical square-well potential with characteristic nuclear dimensions and whose depth has been adjusted to give rise to a situation in which the last occupied neutron orbital is loosely-bound. Spin-orbit couplings are, for the present purpose, ignored. The results of this investigation clearly indicate that nuclear couplings have the predominant role in causing projectile dissociation in many circumstances, even at bombarding energies remarkably below the Coulomb barrier.

  3. Small angle neutron scattering modeling of copper-rich precipitates in steel

    International Nuclear Information System (INIS)

    Spooner, S.

    1997-11-01

    The magnetic to nuclear scattering intensity ratio observed in the scattering from copper rich precipitates in irradiated pressure vessel steels is much smaller than the value of 11.4 expected for a pure copper precipitate in iron. A model for precipitates in pressure vessel steels which matches the observed scattering typically incorporates manganese, nickel, silicon and other elements and it is assumed that the precipitate is non-magnetic. In the present work consideration is given to the effect of composition gradients and ferromagnetic penetration into the precipitate on the small angle scattering cross section for copper rich clusters as distinguished from conventional precipitates. The calculation is an extension of a scattering model for micelles which consist of shells of varying scattering density. A discrepancy between recent SANS scattering experiments on pressure vessel steels was found to be related to applied magnetic field strength. The assumption of cluster structure and its relation to atom probe FIM findings as well as the effects of insufficient field for magnetic saturation is discussed

  4. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  5. Evidence for prevalent Z = 6 magic number in neutron-rich carbon isotopes.

    Science.gov (United States)

    Tran, D T; Ong, H J; Hagen, G; Morris, T D; Aoi, N; Suzuki, T; Kanada-En'yo, Y; Geng, L S; Terashima, S; Tanihata, I; Nguyen, T T; Ayyad, Y; Chan, P Y; Fukuda, M; Geissel, H; Harakeh, M N; Hashimoto, T; Hoang, T H; Ideguchi, E; Inoue, A; Jansen, G R; Kanungo, R; Kawabata, T; Khiem, L H; Lin, W P; Matsuta, K; Mihara, M; Momota, S; Nagae, D; Nguyen, N D; Nishimura, D; Otsuka, T; Ozawa, A; Ren, P P; Sakaguchi, H; Scheidenberger, C; Tanaka, J; Takechi, M; Wada, R; Yamamoto, T

    2018-04-23

    The nuclear shell structure, which originates in the nearly independent motion of nucleons in an average potential, provides an important guide for our understanding of nuclear structure and the underlying nuclear forces. Its most remarkable fingerprint is the existence of the so-called magic numbers of protons and neutrons associated with extra stability. Although the introduction of a phenomenological spin-orbit (SO) coupling force in 1949 helped in explaining the magic numbers, its origins are still open questions. Here, we present experimental evidence for the smallest SO-originated magic number (subshell closure) at the proton number six in 13-20 C obtained from systematic analysis of point-proton distribution radii, electromagnetic transition rates and atomic masses of light nuclei. Performing ab initio calculations on 14,15 C, we show that the observed proton distribution radii and subshell closure can be explained by the state-of-the-art nuclear theory with chiral nucleon-nucleon and three-nucleon forces, which are rooted in the quantum chromodynamics.

  6. Neutron rich 73Ga and 79As isotopes via the (α,p) reaction

    International Nuclear Information System (INIS)

    Rotbard, G.; Vergnes, M.; Berrier-Ronsin, G.; Vernotte, J.

    1979-01-01

    The (α,p) reaction at 26 MeV has been used to study 73 Ga and 79 As with 12 keV resolution (FWHM). The reaction behaves like a simple proton stripping ('spectator' zero coupled neutron pair) and the characteristic shapes of the angular distributions permit to assign new spins and parities. In 73 Ga: 198 keV (5/2 - ), 1116 keV (1/2 - ), 1494 keV (9/2 + ). In 79 As: g.s (3/2 - ), 233 keV (5/2 - ), 499 keV (1/2 - ), 777 keV (9/2 + ), 1806 keV (9/2 + ), 1891 keV (1/2 - ), 1964 keV (9/2 + ). The observed splitting of the Jsup(π)=3/2 - strength in 73 Ga, important as compared to the one observed in 71 Ga, is attributed to a change of structure between N=40 and 42

  7. Triaxial shapes in the ground states of even-even neutron-rich Ru isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Lister, C.J.; Morss, L.R. [and others

    1995-08-01

    Partial level schemes for {sup 108,110,112}Ru, and {sup 114}Ru about which nothing was previously known, were determined from the measurement of prompt, triple-gamma coincidences in {sup 248}Cm fission fragments. A 5-mg {sup 249}Cm source, mixed with 65-mg KCl and pressed in the form of a 7-mm diameter pellet, was used for the experiment. Prompt {gamma} rays emitted from the fission fragments were detected with the Eurogam array at Daresbury, which at that time consisted of 45 Compton suppressed Ge detectors and 5 LEPS spectrometers. Transitions in Ru were identified by gating on {gamma} rays in the complementary Te fragments. Figure I-25 shows the technique used to identify the previously unknown transitions in {sup 114}Ru and its partial level scheme. High spin states up to spin 10 h were observed and the {gamma}-ray branching ratios were determined. The ratios of electric quadrupole transition probabilities deduced from the experimental branching ratios were found to be in good agreement with the predictions of a simple model of rigid triaxial rotor. Our analysis shows that gamma deformation in Ru isotopes is increasing with the neutron number and the gamma value for {sup 112}Ru and {sup 114}Ru is {approximately} 25 degrees. This is one of the highest gamma values encountered in nuclei, suggesting soft triaxial shapes for {sup 112}Ru and {sup 114}Ru. The results of this investigation were published.

  8. Precision mass measurements of neutron-rich Co isotopes beyond N =40

    Science.gov (United States)

    Izzo, C.; Bollen, G.; Brodeur, M.; Eibach, M.; Gulyuz, K.; Holt, J. D.; Kelly, J. M.; Redshaw, M.; Ringle, R.; Sandler, R.; Schwarz, S.; Stroberg, S. R.; Sumithrarachchi, C. S.; Valverde, A. A.; Villari, A. C. C.

    2018-01-01

    The region near Z =28 and N =40 is a subject of great interest for nuclear structure studies due to spectroscopic signatures in 68Ni suggesting a subshell closure at N =40 . Trends in nuclear masses and their derivatives provide a complementary approach to shell structure investigations via separation energies. Penning trap mass spectrometry has provided precise measurements for a number of nuclei in this region; however, a complete picture of the mass surfaces has so far been limited by the large uncertainty remaining for nuclei with N >40 along the iron (Z =26 ) and cobalt (Z =27 ) chains because these species are not available from traditional isotope separator online rare isotope facilities. The Low-Energy Beam and Ion Trap Facility at the National Superconducting Cyclotron Laboratory is the first and only Penning trap mass spectrometer coupled to a fragmentation facility and therefore presents the unique opportunity to perform precise mass measurements of these elusive isotopes. Here we present the first Penning trap measurements of Co,6968, carried out at this facility. Some ambiguity remains as to whether the measured values are ground-state or isomeric-state masses. A detailed discussion is presented to evaluate this question and to motivate future work. In addition, we perform ab initio calculations of ground-state and two-neutron separation energies of cobalt isotopes with the valence-space in-medium similarity renormalization group approach based on a particular set of two- and three-nucleon forces that predict saturation in infinite matter. We discuss the importance of these measurements and calculations for understanding the evolution of nuclear structure near 68Ni.

  9. 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)

  10. Neutronic/Thermal-hydraulic Coupling Technigues for Sodium Cooled Fast Reactor Simulations

    International Nuclear Information System (INIS)

    Ragusa, Jean; Siegel, Andrew; Ruggieri, Jean-Michel

    2010-01-01

    The objective of this project was to test new coupling algorithms and enable efficient and scalable multi-physics simulations of advanced nuclear reactors, with considerations regarding the implementation of such algorithms in massively parallel environments. Numerical tests were carried out to verify the proposed approach and the examples included some reactor transients. The project was directly related to the Sodium Fast Reactor program element of the Generation IV Nuclear Energy Systems Initiative and the Advanced Fuel cycle Initiative, and, supported the requirement of high-fidelity simulation as a mean of achieving the goals of the presidential Global Nuclear Energy Partnership (GNEP) vision.

  11. Neutronic/Thermalhydraulic Coupling Technigues for Sodium Cooled Fast Reactor Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Jean Ragusa; Andrew Siegel; Jean-Michel Ruggieri

    2010-09-28

    The objective of this project was to test new coupling algorithms and enable efficient and scalable multi-physics simulations of advanced nuclear reactors, with considerations regarding the implementation of such algorithms in massively parallel environments. Numerical tests were carried out to verify the proposed approach and the examples included some reactor transients. The project was directly related to the Sodium Fast Reactor program element of the Generation IV Nuclear Energy Systems Initiative and the Advanced Fuel cycle Initiative, and, supported the requirement of high-fidelity simulation as a mean of achieving the goals of the presidential Global Nuclear Energy Partnership (GNEP) vision.

  12. Spes: An intense source of Neutron-Rich Radioactive Beams at Legnaro

    Science.gov (United States)

    Andrighetto, A.; Manzolaro, M.; Corradetti, S.; Scarpa, D.; Monetti, A.; Rossignoli, M.; Ballan, M.; Borgna, F.; D'Agostini, F.; Gramegna, F.; Prete, G.; Meneghetti, G.; Ferrari, M.; Zenoni, A.

    2018-02-01

    The Isotope Separation On-Line (ISOL) method for the production of Radioactive Ion Beams (RIB) is attracting significant interest in the worldwide nuclear physics community. Within this context the SPES (Selective Production of Exotic Species) RIB facility is now under construction at INFN LNL (Istituto Nazionale di Fisica Nucleare Laboratori Nazionali di Legnaro). This technique is established as one of the main techniques for high intensity and high quality beams production. The SPES facility will produce n-rich isotopes by means of a 40 MeV proton beam, emitted by a cyclotron, impinging on a uranium carbide multi-foil fission target. The aim of this work is to describe the most important results obtained by the study of the on-line behavior of the SPES production target assembly. This target system will produce RIBs at a rate of about 1013 fissions per second, it will be able to dissipate a total power of up to 10 kW, and it is planned to work continuously for 2 week-runs of irradiation. ISOL beams of 24 different elements will be produced, therefore a target and ion source development is ongoing to ensure a great variety of produced isotopes and to improve the beam intensity and purity.

  13. Formulary for neutron propagation in sodium-steel media for the fast reactor shields

    International Nuclear Information System (INIS)

    Bouteau, F.; Caumette, P.; Khairallah, A.; Oceraies, Y.; Devillers, C.

    1975-01-01

    The simplified calculational tool (''formulary'') for neutron propagation in the shields of fast reactors, being developed at CEA, has two objectives: to reduce the cost of the major part of design calculations, without a significant loss of accuracy; to facilitate the adjustment of the calculational tool with the results of the program of integral propagation experiments, which is conducted in parallel with the development of the calculational method. The version 0 (i.e. before any adjustment) of the formulary and a first test of its validity as compared to the results of integral measurements are presented [fr

  14. Schottky mass measurements of heavy neutron-rich nuclides in the element range $70\\leq Z\\leq 79$ at the ESR

    CERN Document Server

    Shubina, D; Litvinov, Yu A; Blaum, K; Brandau, C; Bosch, F; Carroll, J J; Casten, R F; Cullen, D M; Cullen, I J; Deo, A Y; Detwiler, B; Dimopoulou, C; Farinon, F; Geissel, H; Haettner, E; Heil, M; Kempley, R S; Kozhuharov, C; Knobel, R; Kurcewicz, J; Kuzminchuk, N; Litvinov, S A; Liu, Z; Mao, R; Nociforo, C; Nolden, F; Patyk, Z; Plass, W R; Prochazka, A; Reed, M W; Sanjari, M S; Scheidenberger, C; Steck, M; Stohlker, Th; Sun, B; Swan, T P D; Trees, G; Walker, P M; Weick, H; Winckler, N; Winkler, M; Woods, P J; Yamaguchi, T; Zhou, C

    2013-01-01

    Storage-ring mass spectrometry was applied to neutron-rich $^{197}$Au projectile fragments. Masses of $^{181,183}$Lu, $^{185,186}$Hf, $^{187,188}$Ta, $^{191}$W, and $^{192,193}$Re nuclei were measured for the first time. The uncertainty of previously known masses of $^{189,190}$W and $^{195}$Os nuclei was improved. Observed irregularities on the smooth two-neutron separation energies for Hf and W isotopes are linked to the collectivity phenomena in the corresponding nuclei.

  15. Evidence for existence of functional monoclinic phase in sodium niobate based solid solution by powder neutron diffraction

    Science.gov (United States)

    Mishra, S. K.; Jauhari, Mrinal; Mittal, R.; Krishna, P. S. R.; Reddy, V. R.; Chaplot, S. L.

    2018-04-01

    We have carried out systematic temperature-dependent neutron diffraction measurements in conjunction with dielectric spectroscopy from 6 to 300 K for sodium niobate based compounds (1-x) NaNbO3-xBaTiO3 (NNBTx). The dielectric constant is measured as a function of both temperature and frequency. It shows an anomaly at different temperatures in cooling and heating cycles and exhibits a large thermal hysteresis of ˜150 K for the composition x = 0.03. The dielectric constant is found to be dispersive in nature and suggests a relaxor ferroelectric behavior. In order to explore structural changes as a function of temperature, we analyzed the powder neutron diffraction data for the compositions x = 0.03 and 0.05. Drastic changes are observed in the powder profiles near 2θ ˜ 30.6°, 32.1°, and 34.6° in the diffraction pattern below 200 K during cooling and above 190 K in heating cycles, respectively. The disappearance of superlattice reflection and splitting in main perovskite peaks provide a signature for structural phase transition. We observed stabilization of a monoclinic phase (Cc) at low temperature. This monoclinic phase is believed to provide a flexible polarization rotation and considered to be directly linked to the high performance piezoelectricity in materials. The thermal hysteresis for composition x = 0.03 is larger than that for x = 0.05. This suggests that the addition of BaTiO3 to NaNbO3 suppresses the thermal hysteresis. It is also observed that the structural phase transition temperature decreases upon increasing the dopant concentration.

  16. Effect of Reflector Material on the Neutronic Characteristics of the Small Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sung Hwan; Baek, Min Ho; Yoo, Jae Woon; Kim, Sang Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    The sodium-cooled fast reactor (SFR) has been chosen as a candidate for the Gen-IV Nuclear Energy Systems Initiative due to the advantages in utilization of uranium resources and reduction of radioactive wastes. Recently, the uranium blanket concept is omitted for a purpose of the non-proliferation, hence the reflector material plays a more important role in reactor core design. Moreover, especially in the Korean prototype SFR, the initial core should startup with low-enriched uranium ({<=} 20 w/o) for 100 {approx} 150 MWe power. This restriction causes significant difficulties to achieve sufficient excess reactivity. Thus, in this paper, core characteristic studies of various reflector materials (HT9, BeO, MgO, and ZrH{sub 1.6}) are performed to enhance the initial core excess reactivity

  17. Evaluation of cross sections for neutron-induced reactions in sodium

    International Nuclear Information System (INIS)

    Larson, D.C.

    1980-09-01

    An evaluation of the neutron-induced cross sections of 23 Na has been done for the energy range from 10 -5 eV to 20 MeV. All significant cross sections are given, including differential cross sections for production of gamma rays. The recommended values are based on experimental data where available, and use results of a consistent model code analysis of available data to predict cross sections where there are no experimental data. This report describes the evaluation that was submitted to the Cross Section Evaluation Working Group (CSEWG) for consideration as a part of the Evaluated Nuclear Data File, Version V, and subsequently issued as MAT 1311. 126 references, 130 figures, 14 tables

  18. Effects of boron neutron capture therapy using borocaptate sodium in combination with a tumor-selective vasoactive agent in mice

    International Nuclear Information System (INIS)

    Ono, Koji; Masunaga, Shin-ichiro; Kinashi, Yuko; Takagaki, Masao; Akaboshi, Mitsuhiko; Suzuki, Minoru; Baba, Hideo.

    1998-01-01

    Boron neutron capture therapy (BNCT) destroys tumor cells by means of α particles and recoil protons emitted by 10 B(n,α) 7 Li reaction. For BNCT to be effective, the tumor/normal tissue concentration ratio of 10 B must be larger than 1.0, because neutron distribution is not selective. We examined the combination of 10 B-enriched borocaptate sodium (BSH) with flavone acetic acid (FAA) as a model compound which causes vascular collapse in squamous cell carcinoma in mice (SCCVII tumors) and would increase the tumor/normal tissue concentration ratio of 10 B. FAA (200 mg/kg, i.p.) was injected, and 5 min later BSH (75 mg/kg, i.v.) was administered, followed 15 to 180 min later by irradiation with thermal neutrons. The 10 B concentrations were measured by prompt gamma ray spectrometry. Without FAA, tumor 10 B concentrations were less than or equal to normal tissue concentrations at all time intervals, except that the concentrations were 1.7- to 2.7-fold greater in tumor than muscle at 15 and 180 min after injection of BSH. With FAA, 10 B concentrations 2.1- to 6.9-fold greater in tumor than in muscle were achieved at all intervals tested. For blood and skin, significant differential accumulations were found in tumors at 120 and 180 min. Tumor/liver ratios were less than 1 at all times. Cell survival was determined by in vivo/in vitro colony assay, and increasing radiosensitization correlated with increasing tumor 10 B concentrations, whether or not they were achieved with FAA. Tumor control rates, determined at 180 days after BNCT, similarly appeared to depend only on 10 B levels at the time of irradiation. Because 10 B levels correlate with the radiation response of tissues, a therapeutic gain would be expected whenever the tumor levels exceed normal tissue levels, such as in tumors located in muscle irradiated at 15-180 min after FAA+BSH, or in those in skin irradiated at 120 and 180 min. (author)

  19. Chlorine and sodium perfusion and electrolyte balance in human tissue and tumours before and during neutron and photon radiotherapy

    Science.gov (United States)

    Koester, L.; Knopf, K.; Auberger, Th

    1997-08-01

    Radiotherapy with nuclear reactor fission neutrons was applied in 49 cases of pre-treated patients with superficial metastases or relapses from primary carcinoma. Measurements of the decay rates of the radiation-induced radioactivity of , and in the irradiated tissue resulted in values for the simultaneous local kinetics of chlorine and sodium, and in approximate data on the electrolyte masses. The electrolytes were present in non-exchangeable and exchangeable compartments of soft tissue. Exchange times of the intravascular to extravascular turnover and the frequencies of the exchange fractions were determined for a series of irradiations. The results have been interpreted in terms of the mean electrolyte exchange rates, of a standardized functional blood flow, and of the supply capacity of the vascular system. In the average of all cases, the regional perfusion was reduced by about 30% by irradiation up to 14 Gy (equivalent photon dose ) connected with an increase in the non-exchangeable fractions. After fractionated doses higher than 14 Gy, functional blood flow and supply capacity increased to 120%, and fixed electrolytes were removed from the irradiated tissue. Data on electrolyte kinetics and vascularity are compared with the literature.

  20. A Neutronic Feasibility Study on the Recycling of an Oxide Fuel in Sodium-Cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Gyu Hong; Choi, Hang Bok

    2006-06-15

    Neutronic feasibility was implemented for the recycling of a mixed oxide fuel in sodium-cooled fast reactors (SFR) through a thermal/mechanical dry process, which is recognized as one of the most proliferation- resistant recycling processes. In order to assess the applicability of a simple dry process which is not capable of completely removing all the fission products from a spent fuel, sensitivity calculations were performed for the reactor physics parameters with a dependency on the fission product removal rate of the recycled spent fuel. The equilibrium core calculations were performed by the REBUS-3 code for a BN-600 core without blanket fuels and a modified core with an increased fuel volume fraction. The reactor performance parameters such as the transuranic content, breeding ratio, peak linear power, burnup reactivity swing and reactivity coefficients were calculated for an equilibrium core under a fixed fuel management scheme. The results showed that a recycling of the oxide fuel in the SFR is feasible if the fission products are removed by more than 70% through the dry process as far as the material balance is concerned. However the physics analysis also showed that some of the physics design parameters are slightly deteriorated. The results of this study indicate that the recycling characteristics can be improved if the dry process can remove more fission products, and the reactor configuration is further optimized or the spent fuel composition is adjusted.

  1. Comparison of neutron diffusion theory codes in two and three space dimensions using a sodium cooled fast reactor benchmark

    International Nuclear Information System (INIS)

    Butland, A.T.D.; Putney, J.; Sweet, D.W.

    1980-04-01

    This report describes work performed to compare two UK neutron diffusion theory codes, TIGAR and SNAP, with published results for eight other codes available abroad. Both mesh edge and mesh centred finite difference diffusion theory codes as well as one axial synthesis code are included in the comparison and a range of iteration procedures are used by them. Comparison is made of calculations for a model of the sodium cooled fast reactor SNR-300 in both triangular and rectangular geometry and for a range of spatial meshes, enabling extrapolations to infinite mesh to be made. Calculated values of the effective multiplication constant, keff, for all the codes, agree very well when extrapolated to infinite mesh, indicating that no significant errors arising from the finite difference approximation but independent of mesh spacing are present in the calculations. The variation of keff with mesh area is found to be linear for the small meshes considered here, with the gradients for the mesh centred and mesh edged codes being of opposite sign. The results obtained using the mesh centred codes TIGAR, SNAP and CITATION agree closely with one another for all the meshes considered; the mesh edge codes agree less closely. (author)

  2. A Neutronic Feasibility Study on the Recycling of an Oxide Fuel in Sodium-Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Roh, Gyu Hong; Choi, Hang Bok

    2006-06-01

    Neutronic feasibility was implemented for the recycling of a mixed oxide fuel in sodium-cooled fast reactors (SFR) through a thermal/mechanical dry process, which is recognized as one of the most proliferation- resistant recycling processes. In order to assess the applicability of a simple dry process which is not capable of completely removing all the fission products from a spent fuel, sensitivity calculations were performed for the reactor physics parameters with a dependency on the fission product removal rate of the recycled spent fuel. The equilibrium core calculations were performed by the REBUS-3 code for a BN-600 core without blanket fuels and a modified core with an increased fuel volume fraction. The reactor performance parameters such as the transuranic content, breeding ratio, peak linear power, burnup reactivity swing and reactivity coefficients were calculated for an equilibrium core under a fixed fuel management scheme. The results showed that a recycling of the oxide fuel in the SFR is feasible if the fission products are removed by more than 70% through the dry process as far as the material balance is concerned. However the physics analysis also showed that some of the physics design parameters are slightly deteriorated. The results of this study indicate that the recycling characteristics can be improved if the dry process can remove more fission products, and the reactor configuration is further optimized or the spent fuel composition is adjusted

  3. 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.)

  4. Neutron activation analysis of copper traces: a study for sodium correction factor

    International Nuclear Information System (INIS)

    Tripathi, A.B.R.; Bhadkambekar, C.A.; Basu, A.K.; Chattopadhyay, N.

    2007-01-01

    Peak ratio correction factors for accurate quantitative determination of copper by NAA via 64 Cu radioisotope in presence of high 24 Na radioactivities has been established. Copper is the principal element as a marker of bullet residues on targets in connection to forensic ballistics cases. Reliable and precise estimation of copper by NAA either via non-destructive way or by resorting to radiochemical separation is of importance in forensic analysis for arriving at definitive inferences. However, majority of samples originating from wearing apparels, paper, leather, skin, glass or any other metal exhibit matrices contain high levels of sodium. The NAA scheme for determination of copper rests on measurements of net counts at 511 KeV which is the positron annihilation peak of 64 Cu. 24 Na also contributes significantly exactly at 511 KeV of gamma energy albeit by different mechanism i.e., by pair production. Therefore, total signal at 511 KeV is contributed by both. The easiest approach for correct estimation of copper traces has been established by the peak ratio correction factor. This has significance as both 64 Cu and 24 Na have comparable half lives, hence, as such time gap measurements cannot improve the situation. The consistency of peak ratio correction factor could be established for a particular geometry. (author)

  5. Neutron-rich rare isotope production from projectile fission of heavy beams in the energy range of 20 MeV/nucleon

    OpenAIRE

    Vonta, N.; Souliotis, G. A.; Loveland, W. D.; Kwon, Y. K.; Tshoo, K.; Jeong, S. C.; Veselsky, M.; Bonasera, A.; Botvina, A.

    2016-01-01

    We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Tr...

  6. A systematic study of band structure and electromagnetic properties of neutron rich odd mass Eu isotopes in the projected shell model framework

    Energy Technology Data Exchange (ETDEWEB)

    Pandit, Rakesh K.; Devi, Rani [University of Jammu, Department of Physics and Electronics, Jammu (India); Khosa, S.K. [Central University of Jammu, Department of Physics and Astronomical Sciences, Jammu (India); Bhat, G.H.; Sheikh, J.A. [University of Kashmir, Department of Physics, Srinagar (India)

    2017-10-15

    The positive and negative parity rotational band structure of the neutron rich odd mass Eu isotopes with neutron numbers ranging from 90 to 96 are investigated up to the high angular momentum. In the theoretical analysis of energy spectra, transition energies and electromagnetic transition probabilities we employ the projected shell model. The calculations successfully describe the formation of the ground and excited band structures from the single particle and multi quasiparticle configurations. Calculated excitation energy spectra, transition energies, exact quantum mechanically calculated B(E2) and B(M1) transition probabilities are compared with experimental data wherever available and a reasonably good agreement is obtained with the observed data. The change in deformation in the ground state band with the increase in angular momentum and the increase in neutron number has also been established. (orig.)

  7. Shape coexistence in the N=19 neutron-rich nucleus 31Mg explored by β–γ spectroscopy of spin-polarized 31Na

    Directory of Open Access Journals (Sweden)

    H. Nishibata

    2017-04-01

    Full Text Available The structure of excited states in the neutron-rich nucleus 31Mg, which is in the region of the “island of inversion” associated with the neutron magic number N=20, is studied by β–γ spectroscopy of spin-polarized 31Na. Among the 31Mg levels below the one neutron separation energy of 2.3 MeV, the spin values of all five positive-parity levels are unambiguously determined by observing the anisotropic β decay. Two rotational bands with Kπ=1/2+ and 1/2− are proposed based on the spins and energies of the levels. Comparison on a level-by-level basis is performed between the experimental results and theoretical calculations by the antisymmetrized molecular dynamics (AMD plus generator coordinate method (GCM. It is found that various nuclear structures coexist in the low excitation energy region in 31Mg.

  8. Study of the tensor correlation in a neutron-rich sd-shell region with the charge- and parity-projected Hartree-Fock method

    International Nuclear Information System (INIS)

    Sugimoto, Satoru; Toki, Hiroshi; Ikeda, Kiyomi

    2008-01-01

    We study the effect of the tensor force on nuclear structure with mean-field and beyond-mean-field methods. An important correlation induced by the tensor force is two-particle-two-hole (2p2h) correlation, which cannot be treated with a usual mean-filed method. To treat the 2p2h tensor correlation, we develop a new framework (charge- and parity-projected Hartree-Fock (CPPHF) method), which is a beyond-mean-field method. In the CPPHF method, we introduce single-particle states with parity and charge mixing. The parity and charge projections are performed on a total wave function before variation. We apply the CPPHF method to oxygen isotopes including neutron-rich ones. The potential energy from the tensor force has the same order of magnitude with that from the LS force and becomes smaller with neutron number, which indicates that excess neutrons do not contribute to the 2p2h tensor correlation significantly. We also study the effect of the tensor force on spin-orbit-splitting (ls-splitting) in a neutron-rich fluorine isotope 23 F. The tensor force reduces the ls-splitting for the proton d-orbits by about 3 MeV. This effect is important to reproduce the experimental value. We also find that the 2p2h tensor correlation does not affect the ls-splitting in 23 F

  9. 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...

  10. 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...

  11. Study of reactivity feedbacks in a sodium-cooled fast reactor: new methodology based on perturbation theory for evaluating neutronic uncertainties

    International Nuclear Information System (INIS)

    Bouret, Cyrille

    2014-01-01

    Fast reactors (FR) can give value to the plutonium produced by the existing light water reactors and allow the transmutation of a significant part of the final nuclear waste. These features offer industrial prospects for this technology and new projects are currently studied in the world such as ASTRID prototype in France. Future FRs will have also to satisfy new requirements in terms of competitiveness, safety and reliability. In this context, the new core concept envisaged for ASTRID incorporate innovative features that improve the safety of the reactor in case of accident. The proposed design achieves a sodium voiding effect close to zero: it includes a fertile plate in the middle of the core and a sodium plenum in the upper part in order to increase the neutron leakage in case of sodium voiding. This heterogeneous design represents a challenge for the calculation tools and methods used so far to evaluate the neutronic parameters in traditional homogeneous cores. These methods have been improved over the thesis to rigorously treat the neutron streaming, especially at the mediums interfaces. These enhancements have consisted in the development of a specific analysis methodology based on perturbation theory and using a modern three dimensional Sn transport solver. This work has allowed on the one hand, to reduce the bias on static neutronic parameters in comparison with Monte Carlo methods, and, on the other hand, to obtain more accurate spatial distributions of neutronic effects including the reactivity feedback coefficients used for transient analysis. The analysis of the core behavior during transients has also allowed estimating the impact of reactivity feedback coefficients assessment improvements. In conjunction with this work, innovative methods based on the evaluation of local sensitivities coefficients have been proposed to assess the uncertainties associated to local reactivity effects. These uncertainties include the correlations between the different

  12. Purified rutin and rutin-rich asparagus attenuates disease severity and tissue damage following dextran sodium sulfate-induced colitis.

    Science.gov (United States)

    Power, Krista A; Lu, Jenifer T; Monk, Jennifer M; Lepp, Dion; Wu, Wenqing; Zhang, Claire; Liu, Ronghua; Tsao, Rong; Robinson, Lindsay E; Wood, Geoffrey A; Wolyn, David J

    2016-11-01

    This study investigated the effects of cooked whole asparagus (ASP) versus its equivalent level of purified flavonoid glycoside, rutin (RUT), on dextran sodium sulfate (DSS)-induced colitis and subsequent colitis recovery in mice. C57BL/6 male mice were fed an AIN-93G basal diet (BD), or BD supplemented with 2% cooked ASP or 0.025% RUT for 2 wks prior to and during colitis induction with 2% DSS in water for 7 days, followed by 5 days colitis recovery. In colitic mice, both ASP and RUT upregulated mediators of improved barrier integrity and enhanced mucosal injury repair (e.g. Muc1, IL-22, Rho-A, Rac1, and Reg3γ), increased the proportion of mouse survival, and improved disease activity index. RUT had the greatest effect in attenuating DSS-induced colonic damage indicated by increased crypt and goblet cell restitution, reduced colonic myeloperoxidase, as well as attenuated DSS-induced microbial dysbiosis (reduced Enterobacteriaceae and Bacteroides, and increased unassigned Clostridales, Oscillospira, Lactobacillus, and Bifidobacterium). These findings demonstrate that dietary cooked ASP and its flavonoid glycoside, RUT, may be useful in attenuating colitis severity by modulating the colonic microenvironment resulting in reduced colonic inflammation, promotion of colonic mucosal injury repair, and attenuation of colitis-associated microbial dysbiosis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Genotoxicity, acute and subchronic toxicity studies in rats of a rooster comb extract rich in sodium hyaluronate.

    Science.gov (United States)

    Canut, Lourdes; Zapatero, Jorge; López, Sílvia; Torrent, Anna; Ruhí, Ramon; Vicente, Laura

    2012-04-01

    The toxicity of a rooster comb extract (IB0004) that contains mainly sodium hyaluronate was assessed in acute and subchronic studies and in a bacterial reverse mutation assay. In a single dose acute study, male and female rats were administered 2000 mg/kg body weight (bw) of the product and observed for 14 days. No mortality was recorded, thus it was considered that the minimum lethal dose for rats by oral route was greater than 2000 mg/kg bw. A 90-day subchronic study (5, 55 and 600 mg/kg bw/day, oral gavage) with 50 male and 50 female Wistar-Hannover rats produced no significant adverse effects on food consumption, body weight, mortality, clinical biochemistry, hematology, gross pathology, and histopathology. Although some differences were observed between the treated and control animals in body weight gain (%) and some hematological parameters, these changes were generally minor in nature and, are considered to be of no toxicological significance. The no-observable-adverse-effects level was established at 600 mg/kg bw/day. There was no evidence of mutagenic activity in Salmonella typhimurium TA98, TA100, TA1535 and TA1537 or in Escherichia coli WP2 uvra pkM101. In conclusion, the results from these safety studies support the safety of rooster comb extract IB0004 in food. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Deep-UV Raman spectroscopic analysis of structure and dissolution rates of silica-rich sodium borosilicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Eric M [ORNL; WindischJr., Charles F. [Pacific Northwest National Laboratory (PNNL); Burton, Sarah D. [Pacific Northwest National Laboratory (PNNL); Bovaird, Chase C. [Pacific Northwest National Laboratory (PNNL)

    2010-01-01

    As part of ongoing studies to evaluate relationships between structure and rates of dissolution of silicate glasses in aqueous media, sodium borosilicate glasses of composition Na2O xB2O3 (3 x)SiO2, with x 1 (Na2O/B2O3 ratio 1), were analyzed using deep-UV Raman spectroscopy. Results were quantified in terms of the fraction of SiO4 tetrahedra with one non-bridging oxygen (Q3) and then correlated with Na2O and B2O3 content. The Q3 fractionwas found to increase with increasing Na2O content, in agreement with studies on related glasses, and, as long as the value of x was not too high, this contributed to higher rates of dissolution in single pass flow-through testing. In contrast, dissolution rates were less strongly determined by the Q3 fraction when the value of x was near unity, and appeared to grow larger upon further reduction of the Q3 fraction. Results were interpreted to indicate the increasingly important role of network hydrolysis in the glass dissolution mechanism as the BO4 tetrahedron replaces the Q3 unit as the charge-compensating structure for Na+ ions. Finally, the use of deep-UV Raman spectroscopy was found to be advantageous in studying finely powdered glasses in cases where visible Raman spectroscopy suffered from weak Raman scattering and fluorescence interference.

  15. Penning-trap mass measurements of the neutron-rich K and Ca isotopes: Resurgence of the N=28 shell strength

    Science.gov (United States)

    Lapierre, A.; Brodeur, M.; Brunner, T.; Ettenauer, S.; Finlay, P.; Gallant, A. T.; Simon, V. V.; Delheij, P.; Lunney, D.; Ringle, R.; Savajols, H.; Dilling, J.

    2012-02-01

    We present Penning-trap mass measurements of neutron-rich 44,47-50K and 49,50Ca isotopes carried out at the TITAN facility at TRIUMF-ISAC. The 44K mass measurement was performed with a charge-bred 4+ ion utilizing the TITAN electron beam ion trap and agrees with the literature. The mass excesses obtained for 47K and 49,50Ca are more precise and agree with the values published in the 2003 Atomic Mass Evaluation (AME’03). The 48,49,50K mass excesses are more precise than the AME’03 values by more than 1 order of magnitude. For 48,49K, we find deviations of 7σ and 10σ, respectively. The new 49K mass excess lowers significantly the two-neutron separation energy at the neutron number N=30 compared with the separation energy calculated from the AME’03 mass-excess values and thus increases the N=28 neutron-shell gap energy at Z=19 by approximately 1 MeV.

  16. Z dependence of the N=152 deformed shell gap: In-beam γ-ray spectroscopy of neutron-rich 245,246Pu

    International Nuclear Information System (INIS)

    Makii, H.; Ishii, T.; Asai, M.; Tsukada, K.; Toyoshima, A.; Ichikawa, S.; Matsuda, M.; Makishima, A.; Kaneko, J.; Toume, H.; Shigematsu, S.; Kohno, T.; Ogawa, M.

    2007-01-01

    We have measured in-beam γ rays in the neutron-rich 246 Pu 152 and 245 Pu 151 nuclei by means of 244 Pu( 18 O, 16 O) 246 Pu and 244 Pu( 18 O, 17 O) 245 Pu neutron transfer reactions, respectively. The γ rays emitted from 246 Pu ( 245 Pu) were identified by selecting the kinetic energy of scattered 16 O ( 17 O) detected by Si ΔE-E detectors. The ground-state band of 246 Pu was established up to the 12 + state. We have found that the shell gap of N=152 is reduced in energy with decreasing atomic number by extending the systematics of the one-quasiparticle energies in N=151 nuclei into those in 245 Pu. This reduction of the shell gap clearly affects the 2 + energy of the ground-state band of 246 Pu

  17. 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.

  18. 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)

  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. Vacancy enhanced formation and phase transition of Cu-rich precipitates in α - iron under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lv, G. C. [Basic Experimental Center of Natural Science, University of Science and Technology Beijing, Beijing, 100083 (China); Corrosion and Protection Center, Key Laboratory of Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing, 100083 (China); Zhang, H. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada, T6G2V4 (Canada); He, X. F.; Yang, W. [China Institute of Atomic Energy, Beijing, 102413 (China); Su, Y. J., E-mail: yjsu@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory of Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing, 100083 (China)

    2016-04-15

    In this paper, we employed both molecular statics and molecular dynamics simulation methods to investigate the role of vacancies in the formation and phase transition of Cu-rich precipitates in α-iron. The results indicated that vacancies promoted the diffusion of Cu atoms to form Cu-rich precipitates. After Cu-rich precipitates formed, they further trapped vacancies. The supersaturated vacancy concentration in the Cu-rich precipitate induced a shear strain, which triggered the phase transition from bcc to fcc structure by transforming the initial bcc (110) plane into fcc (111) plane. In addition, the formation of the fcc-twin structure and the stacking fault structure in the Cu-rich precipitates was observed in dynamics simulations.

  1. Study of the moderating effect of salts on the sodium-water reaction on the cleaning of irradiated fuel assemblies from fast neutron reactors, using fluid sodium heat transfer

    International Nuclear Information System (INIS)

    Lacroix, Marie

    2014-01-01

    Within the framework of the development of generation IV reactors one of the research tracks is related to the development of fast neutron reactors using fluid sodium heat transfer. The CEA (French Alternative Energies and Atomic Energy Commission) plans to build a prototype of reactor of this type called 'ASTRID'. To address development requirements for this prototype, research is in progress on the reactor's availability and in particular on the reduction of the washing duration for residual sodium fuel assemblies during their discharge. In fact, because sodium is very reactive with water (presently the only available process), the washing is done, for example, by very gradual addition. A solution currently being studied at the CEA and which is the subject of this thesis report consists of the addition of an aqueous salts solutions to the washing water in order to slow down the kinetic reaction. This doctoral dissertation describes the various salts, which have been evaluated and aims to explain their action mode. (author) [fr

  2. Lifetime measurements in neutron-rich isotopes close to N = 40 and development of a simulation tool for RDDS spectra

    International Nuclear Information System (INIS)

    Braunroth, Thomas Christian

    2017-01-01

    interest are the neutron-rich 59,61 Mn isotopes (Z=25), for which level lifetimes of the 7/2 - 1 , 9/2 - 1 and 11/2 - 1 states were determined (in 61 Mn the assignment is only tentative). In addition, level lifetimes in 63 Mn of the tentatively assigned (7/2 - 1 ) and (9/2 - 1 ) states were evaluated. The results are compared to shell-model calculations using the fp interaction KB3G as well as the state-of-the-art interaction LNPS-m. The present data indicates a structural change close to N=36. The experimental data for 61 Mn suggests that the B(M1) value for the 7/2 - 1 → 5/2 - gs is underestimated by the LNPS-m interaction when free g factors are used. In the second part of this thesis, a tool is presented which allows to generate γ-ray spectra of lifetime studies based on the electromagnetic Doppler-shift using empirical parameters. The tool is highly flexible which enables the incorporation of various experimental bounding conditions. It is applied to investigate the influence of velocity distributions on the lifetime analysis and results indicate that systematic deviations are minimized if distance-dependent mean recoil velocities are taken into account.

  3. Lifetime measurements in neutron-rich isotopes close to N = 40 and development of a simulation tool for RDDS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Braunroth, Thomas Christian

    2017-10-10

    degree of quadrupole deformation. Other isotopes that were produced in the experiment were investigated with respect to the identification of γ-ray transitions and level lifetimes. Of particular interest are the neutron-rich {sup 59,61}Mn isotopes (Z=25), for which level lifetimes of the 7/2{sup -}{sub 1}, 9/2{sup -}{sub 1} and 11/2{sup -}{sub 1} states were determined (in {sup 61}Mn the assignment is only tentative). In addition, level lifetimes in {sup 63}Mn of the tentatively assigned (7/2{sup -}{sub 1}) and (9/2{sup -}{sub 1}) states were evaluated. The results are compared to shell-model calculations using the fp interaction KB3G as well as the state-of-the-art interaction LNPS-m. The present data indicates a structural change close to N=36. The experimental data for {sup 61}Mn suggests that the B(M1) value for the 7/2{sup -}{sub 1} → 5/2{sup -}{sub gs} is underestimated by the LNPS-m interaction when free g factors are used. In the second part of this thesis, a tool is presented which allows to generate γ-ray spectra of lifetime studies based on the electromagnetic Doppler-shift using empirical parameters. The tool is highly flexible which enables the incorporation of various experimental bounding conditions. It is applied to investigate the influence of velocity distributions on the lifetime analysis and results indicate that systematic deviations are minimized if distance-dependent mean recoil velocities are taken into account.

  4. Study of the structure of light neutron rich nucleus with the Tonnerre array; Etude de la structure de noyaux legers riches en neutrons a l'aide du multidetecteur Tonnerre

    Energy Technology Data Exchange (ETDEWEB)

    Pietri, St

    2003-06-01

    This work concern the technical development made on the multidetector TONNERRE and the study of the {sup 34}Si nucleus by a complete beta-neutron-gamma spectroscopy. In the first part various tests performed on modules of the detector in the 'Centre d'Etude de Bruyere le Chatel' are presented. A modification of the embassies of the photomultipliers tubes allows to gain more than 50% in the neutron efficiency and to obtain a threshold lower than 300 keV for the neutron energy. A complete C++ simulation of the neutron propagation in the array was carried out. It explains that the slow component of the light output of the scintillator may be responsible of the shape of the time-of-flight spectrum. The second part of these report presents the experiment devoted to the study of the structure of the {sup 34}Si from the beta decay of the {sup 34}Al. It was performed at the GANIL facility using the TONNERRE array and germanium of ENOGAM. The {sup 34}Al was produced by projectile fragmentation of a {sup 36}S beam of 50 MeV/A in a target of {sup 9}Be. A complete beta scheme of the {sup 34}Al is proposed. Eight neutron lines following the {sup 34}Al decay were observed for the first time. Finally we suggest that a monopolar transition could occur in the {sup 34}Si nucleus signing a O{sup +}{sub 2} state at 2133 keV. (author)

  5. New results from isochronous mass measurements of neutron-rich uranium fission fragments with the FRS-ESR-facility at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Knoebel, R.; Litvinov, Yu.A.; Weick, H.; Bosch, F.; Boutin, D.; Dimopoulou, C.; Dolinskii, A.; Franczak, B.; Franzke, B.; Kozhuharov, C.; Kurcewicz, J.; Litvinov, S.A.; Matos, M.; Mazzocco, M.; Muenzenberg, G.; Nociforo, C.; Nolden, F.; Stadlmann, J.; Steck, M.; Winkler, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Diwisch, M. [Justus-Liebig-Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Geissel, H.; Plass, W.R.; Scheidenberger, C.; Chen, L. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Justus-Liebig-Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Patyk, Z. [National Centre for Nuclear Research - NCBJ Swierk, Warszawa (Poland); Sun, B. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); Hausmann, M. [Michigan State University, East Lansing, MI (United States); Nakajima, S.; Suzuki, T.; Yamaguchi, T. [Saitama University, Department of Physics, Saitama (Japan); Ohtsubo, T. [Niigata University, Department of Physics, Niigata (Japan); Ozawa, A. [University of Tsukuba, Institute of Physics, Ibaraki (Japan); Walker, P.M. [University of Surrey, Department of Physics, Guildford (United Kingdom)

    2016-05-15

    Masses of uranium fission fragments have been measured with the FRagment Separator (FRS) combined with the Experimental Storage Ring (ESR) at GSI. A 410-415 MeV/u {sup 238}U projectile beam was fast extracted from the synchrotron SIS-18 with an average intensity of 10{sup 9}/spill. The projectiles were focused on a 1g/cm{sup 2} beryllium target at the entrance of the FRS to create neutron-rich isotopes via abrasion-fission. The fission fragments were spatially separated with the FRS and injected into the isochronous storage ring ESR for fast mass measurements without applying cooling. The Isochronous Mass Spectrometry (IMS) was performed under two different experimental conditions, with and without B ρ-tagging at the high-resolution dispersive central focal plane of the FRS. The evaluation has been done for the combined data sets from both experiments with a new method of data analysis. The use of a correlation matrix has provided experimental mass values for 23 different neutron-rich isotopes for the first time and 6 masses with improved values. The new masses were obtained for nuclides in the element range from Se to Ce. The applied analysis has given access even to rare isotopes detected with an intensity of a few atoms per week. The novel data analysis and systematic error determination are described and the results are compared with extrapolations of experimental values and theoretical models. (orig.)

  6. 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.

  7. ${\\beta}$-decay studies of neutron-rich $^{61-70}$Mn isotopes with the new LISOL ${\\beta}$-decay setup

    CERN Multimedia

    Diriken, J V J

    2008-01-01

    The aim of this proposal is to gather new information that will serve as benchmark to test shell model calculations in the region below $^{68}$Ni, where proper residual interactions are still under development. More specifically, the ${\\beta}$-decay experiment of the $^{61-70}$Mn isotopes will highlight the development of collectivity in the Fe isotopes and its daughters. At ISOLDE, neutron-rich Mn isotopes are produced with a UC$_{x}$ target and selective laser ionization. These beams are particularly pure and reasonable yields are obtained for the neutron-rich short lived $^{61-70}$Mn isotopes. We propose to perform ${\\beta}$-decay studies on $^{61-70}$Mn utilizing the newly-developed "LISOL ${\\beta}$-decay setup", consisting of two MINIBALL cluster Ge detectors and a standard tape station. The use of digital electronics in the readout of these detectors enables us to perform a "slow correlation technique" which should indicate the possible existence of isomers in the daughter nuclei.

  8. System analytical studies on ground state properties of neutron-rich nuclides in the nuclear mass region A ≅ 100

    International Nuclear Information System (INIS)

    Toenhardt, M.

    1987-01-01

    In this thesis only nuclei with even proton and even neutron number have been studied. This constraint allows to use a for the description of excitation spectra very successful model, the interacting boson model (IBM) and to combine this with the density functional method. From the obtained Hamiltonian via an energy-density functional an effective potential is constructed which can be applied in the framework of the density-functional method in order to calculate ground state energies and densities. From the density distributions radii and values for the static deformation are determined. As further ground state property the separation energy for two neutrons is studied. (orig./HSI) [de

  9. 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...

  10. Determination of neutron dose from criticality accidents with bioassays for sodium-24 in blood and phosphorus-32 in hair

    International Nuclear Information System (INIS)

    Feng, Y.; Miller, L.F.; Brown, K.S.; Casson, W.H.; Mei, G.T.; Thein, M.

    1993-06-01

    A comprehensive review of accident neutron dosimetry using blood and hair analysis was performed and is summarized in this report. Experiments and calculations were conducted at Oak Ridge National Laboratory (ORNL) and the University of Tennessee (UT) to develop measurement techniques for the activity of 24 Na in blood and 32 P in hair for nuclear accident dosimetry. An operating procedure was established for the measurement of 24 Na in blood using an HPGe detector system. The sensitivity of the measurement for a 20-mL sample is 0.01-0.02 Gy of total neutron dose for hard spectra and below 0.005 Gy for soft spectra based on a 30- to 60-min counting time. The operating procedures for direct counting of hair samples are established using a liquid scintillation detector. Approximately 0.06-0.1 Gy of total neutron dose can be measured from a 1-g hair sample using this procedure. Detailed procedures for chemical dissolution and ashing of hair samples are also developed. A method is proposed to use blood and hair analysis for assessing neutron dose based on a collection of 98 neutron spectra. Ninety-eight blood activity-to-dose conversion factors were calculated. The calculated results for an uncollided fission spectrum compare favorably with previously published data for fission neutrons. This nuclear accident dosimetry system makes it possible to estimate an individual's neutron dose within a few hours after an accident if the accident spectrum can be approximated from one of 98 tabulated neutron spectrum descriptions. If the information on accident and spectrum description is not available, the activity ratio of 32 P in hair and 24 Na in blood can provide information related to the neutron spectrum for dose assessment

  11. Single- and two-phase flow modeling for coupled neutronics / thermal-hydraulics transient analysis of advanced sodium-cooled fast reactors

    International Nuclear Information System (INIS)

    Chenu, A.

    2011-10-01

    Nuclear power is nowadays in the front rank as regards helping to meet the growing worldwide energy demand while avoiding an excessive increase in greenhouse gas emissions. However, the operating nuclear power plants are mainly thermal-neutron reactors and, as such, can not be maintained on the basis of the currently identified uranium resources beyond one century at the present consumption rate. Sustainability of nuclear power thus involves closure of the fuel cycle through breeding. With a uranium-based fuel, breeding can only be achieved using a fast-neutron reactor. Sodium-cooled fast reactor (SFR) technology benefits from 400 reactor-years of accumulated experience and is thus a prime candidate for the implementation of so-called Generation-IV nuclear energy systems. In this context, the safety demonstration of SFRs remains a major Research and Development related issue. The current research aims at the development of a computational tool for the in-depth understanding of SFR core behaviour during accidental transients, particularly those including boiling of the coolant. An accurate modelling of the core physics during such transients requires the coupling between 3D neutron kinetics and thermal-hydraulics in the core, to account for the strong interactions between the two-phase coolant flow and power variations caused by the sodium void effect. The present study is specifically focused upon models for the representation of sodium two-phase flow. The extension of the thermal-hydraulics TRACE code, previously limited to the simulation of single-phase sodium flow, has been carried out through the implementation of equations-of-state and closure relations specific to sodium. The different correlations have then been implemented as options. From the validation study carried out, it has been possible to recommend a set of models which provide satisfactory results, while considering annular flow as the dominant regime up to dryout and a smooth breakdown of the

  12. Studies on the rice seed (Oryza sativa) sensitivity to gama radiation, neutrons di-enthyl sulphate (DES) and sodium azide (SA)

    International Nuclear Information System (INIS)

    Guimaraes, E.P.

    1978-04-01

    Dry rice seeds of 'Dourado Precoce' variety were treated with gama-rays, thermal and fast neutrons, di-ethyl sulphate (DES) and sodium azide (SA). Biologial effects on survival, seedling height, plant fertility and chlorophy 11 mutation frequency were studied in the M 1 generation. The data obtained were analysed by 'independent test'. Survival was not affected by increased gama ray dosage, but by increased DES and SA dosages, as well as by SA treatments with increased solution acidity for seeds pretreated in distilled water. Seedling height was decreased with the increase of gama-ray dosage, DES concentration. SA acidity and concentration. Plant fertility was reduced drastically with higher gama-ray and neutron dosages and with high SA acidity and concentrations. The maximum chlorophy 11 mutation frequency was obtained in the SA treatment. Seeds pretreated with distilled water showed larger physiological damages in the SA treatments and higher mutation frequencies. Regarding chlorophyll mutation frequency, thermal neutrons were more efficient than gama-rays. SA was the most efficient mutagen used . DES showed lower physiological damages in the M 1 plants, but did not induce mutations in the used conditions [pt

  13. Effects of sodium citrate and acid citrate dextrose solutions on cell counts and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel.

    Science.gov (United States)

    Giraldo, Carlos E; Álvarez, María E; Carmona, Jorge U

    2015-03-14

    There is a lack information on the effects of the most commonly used anticoagulants for equine platelet rich plasmas (PRPs) elaboration on cell counts and growth factor release from platelet rich gels (PRGs). The aims of this study were 1) to compare the effects of the anticoagulants sodium citrate (SC), acid citrate dextrose solution A (ACD-A) and ACD-B on platelet (PLT), leukocyte (WBC) and on some parameters associated to platelet activation including mean platelet volume (MPV) and platelet distribution width (PDW) between whole blood, pure PRP (P-PRP) and platelet-poor plasma (PPP); 2) to compare transforming growth factor beta 1 (TGF-β(1)) and platelet-derived growth factor isoform BB (PDGF-BB) concentrations in supernatants from pure PRG (P-PRG), platelet-poor gel (PPG), P-PRP lysate (positive control) and plasma (negative control); 3) to establish the possible correlations between all the studied cellular and molecular parameters. In all cases the three anticoagulants produced P-PRPs with significantly higher PLT counts compared with whole blood and PPP. The concentrations of WBCs were similar between P-PRP and whole blood, but significantly lower in PPP. The type of anticoagulant did not significantly affect the cell counts for each blood component. The anticoagulants also did not affect the MPV and PDW parameters. Independently of the anticoagulant used, all blood components presented significantly different concentrations of PDGF-BB and TGF-β(1). The highest growth factor (GF) concentrations were observed from P-PRP lysates, followed by PRG supernatants, PPP lysates, PPG supernatants and plasma. Significant correlations were observed between PLT and WBC counts (ρ = 0.80), PLT count and TGF-β(1) concentration (ρ = 0.85), PLT count and PDGF-BB concentration (ρ = 0.80) and PDGF-BB and TGF-β(1) concentrations (ρ = 0.75). The type of anticoagulant was not correlated with any of the variables evaluated. The anticoagulants did not

  14. 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)

  15. 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)

  16. Deep inelastic reactions and isomers in neutron-rich nuclei across the perimeter of the A = 180 - 190 deformed region

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Lane, G.J.; Byrne, A.P.; Watanabe, H.; Hughes, R.O.; Kondev, F.G.; Carpenter, M.P.; Janssens, R.V.F.; Lauritsen, T.; Lister, C.J.; Seweryniak, D.; Zhu, S.; Chowdhury, P.; Shi, Y.; Xu, F.R.

    2014-01-01

    Recent results on high-spin isomers populated in deep-inelastic reactions in the transitional tungsten-osmium region are outlined with a focus on 190 Os, 192 Os and 194 Os. As well as the characterization of several two-quasineutron isomers, the 12 + and 20 + isomers in 192 Os are interpreted as manifestations of maximal rotation alignment within the neutron i(13/2) and possibly proton h(11/2) shells at oblate deformation. (authors)

  17. Hartree-Fock calculation of nuclear binding energy of sodium isotopes

    International Nuclear Information System (INIS)

    Campi, X.; Flocard, H.

    1975-01-01

    Mass spectrometer measurements of the neutron rich sodium isotopes show a sudden increase at 31 Na in the values of the two neutron separation energies. The spherical shell model naturally predicts a sudden decrease at 32 Na after the N=20 shell closure. It is proposed that the explanation for this disagreement lies in the fact that sodium isotopes in this mass region are strongly deformed due to the filling of negative parity orbitals from the 1f(7/2) shell. Hartree-Fock calculations are presented in support of this conjecture [fr

  18. Mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter within the relativistic impulse approximation

    International Nuclear Information System (INIS)

    Jiang Weizhou; Li Baoan; Chen Liewen

    2007-01-01

    The mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter are investigated using the nucleon optical potential obtained within the relativistic impulse approximation with the empirical nucleon-nucleon scattering amplitudes and the nuclear densities obtained in the relativistic mean-field model. It is found that the isospin-splitting of nucleon mean free paths, sensitive to the imaginary part of the symmetry potential, changes its sign at certain high kinetic energy. The in-medium nucleon-nucleon cross sections are analytically and numerically demonstrated to be essentially independent of the isospin asymmetry of the medium and increase linearly with density in the high-energy region where the relativistic impulse approximation is applicable

  19. First observation of the beta decay of neutron-rich $^{218}Bi$ by the pulsed-release technique and resonant laser ionization

    CERN Document Server

    De Witte, H; Borzov, I N; Caurier, E; Cederkäll, J; De Smet, A; Eckhaudt, S; Fedorov, D V; Fedosseev, V; Franchoo, S; Górska, M; Grawe, H; Huber, G; Huyse, M; Janas, Z; Köster, U; Kurcewicz, W; Kurpeta, J; Plochocki, A; Van Duppen, P; Van de Vel, K; Weissman, L

    2004-01-01

    The neutron-rich isotope /sup 218/Bi has been produced in proton- induced spallation of a uranium carbide target at the ISOLDE facility at CERN, extracted from the ion source by the pulsed-release technique and resonant laser ionization, and its beta decay is studied for the first time. A half-life of 33(1)s was measured and is discussed in the self-consistent continuum-quasi particle-random- phase approximation framework that includes Gamow-Teller and first- forbidden transitions. A level scheme was constructed for /sup 218 /Po, and a deexcitation pattern of stretched E2 transitions 8/sup +/ to 6/sup +/ to 4/sup +/ to 2/sup +/ to 0/sup +/ to the ground state is suggested. Shell-model calculations based on the Kuo-Herling interaction reproduce the experimental results satisfactorily. (28 refs).

  20. β-decay half-lives of neutron-rich isotopes of Fe, Co, Ni involved in the beginning of the r-process

    International Nuclear Information System (INIS)

    Czajkowski, S.; Bernas, M.; Brissot, R.

    1992-01-01

    The very neutron-rich Fe- to Ni-isotopes are of interest since they are located at the very beginning of the astrophysical r-process path. The β-decay half-lives of several isotopes, identified in thermal fission of 235 U or 239 Pu, have been measured at the ILL high-flux reactor using the Lohengrin spectrometer. Half-lives have been determined from time-correlations analysis between the fragment implantation and the detection of the subsequent β-particles in the same detector. With the fragment separator FRS , at GSI, the projectile fragments of 86 Kr have been separated. The β-decay half-life of 65 Fe has been measured. Received: (from VMMAIL[FRSAC11 for XIN[IAEA1 via NJE)

  1. Discovery and cross-section measurement of neutron-rich isotopes in the element range from neodymium to platinum with the FRS

    International Nuclear Information System (INIS)

    Kurcewicz, J.; Farinon, F.; Geissel, H.; Pietri, S.; Nociforo, C.; Prochazka, A.; Weick, H.; Winfield, J.S.; Estradé, A.; Allegro, P.R.P.; Bail, A.; Bélier, G.; Benlliure, J.; Benzoni, G.; Bunce, M.; Bowry, M.; Caballero-Folch, R.

    2012-01-01

    Using the high-resolution performance of the fragment separator FRS at GSI we have discovered 60 new neutron-rich isotopes in the atomic number range of 60⩽Z⩽78. The new isotopes were unambiguously identified in reactions with a 238 U beam impinging on a Be target at 1 GeV/nucleon. The production cross-section for the new isotopes have been measured down to the pico-barn level and compared with predictions of different model calculations. For elements above hafnium fragmentation is the dominant reaction mechanism which creates the new isotopes, whereas fission plays a dominant role for the production of the new isotopes up to thulium.

  2. Discovery and cross-section measurement of neutron-rich isotopes in the element range from neodymium to platinum with the FRS

    Energy Technology Data Exchange (ETDEWEB)

    Kurcewicz, J., E-mail: j.kurcewicz@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Farinon, F.; Geissel, H. [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Justus-Liebig-Universitaet Giessen, 35392 Giessen (Germany); Pietri, S.; Nociforo, C. [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Prochazka, A. [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Justus-Liebig-Universitaet Giessen, 35392 Giessen (Germany); Weick, H.; Winfield, J.S. [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Estrade, A. [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Astronomy and Physics Department, Saint Mary' s University, Halifax, Nova Scotia B3H 3C3 (Canada); Allegro, P.R.P. [Institute of Physics, Universidade de Sao Paulo, CEP 05508-090 Cidade Universitaria, Sao Paulo (Brazil); Bail, A.; Belier, G. [CEA DAM DiF, 91290 Arpajon Cedex (France); Benlliure, J. [Universidad de Santiago de Compostela, E-15706 Santiago de Compostella (Spain); Benzoni, G. [INFN sezione di Milano, I-20133 Milano (Italy); Bunce, M.; Bowry, M. [Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH (United Kingdom); Caballero-Folch, R. [Universitat Politecnica de Catalunya, 08034 Barcelona (Spain); and others

    2012-10-31

    Using the high-resolution performance of the fragment separator FRS at GSI we have discovered 60 new neutron-rich isotopes in the atomic number range of 60 Less-Than-Or-Slanted-Equal-To Z Less-Than-Or-Slanted-Equal-To 78. The new isotopes were unambiguously identified in reactions with a {sup 238}U beam impinging on a Be target at 1 GeV/nucleon. The production cross-section for the new isotopes have been measured down to the pico-barn level and compared with predictions of different model calculations. For elements above hafnium fragmentation is the dominant reaction mechanism which creates the new isotopes, whereas fission plays a dominant role for the production of the new isotopes up to thulium.

  3. Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

    Science.gov (United States)

    Clément, E; Zielińska, M; Görgen, A; Korten, W; Péru, S; Libert, J; Goutte, H; Hilaire, S; Bastin, B; Bauer, C; Blazhev, A; Bree, N; Bruyneel, B; Butler, P A; Butterworth, J; Delahaye, P; Dijon, A; Doherty, D T; Ekström, A; Fitzpatrick, C; Fransen, C; Georgiev, G; Gernhäuser, R; Hess, H; Iwanicki, J; Jenkins, D G; Larsen, A C; Ljungvall, J; Lutter, R; Marley, P; Moschner, K; Napiorkowski, P J; Pakarinen, J; Petts, A; Reiter, P; Renstrøm, T; Seidlitz, M; Siebeck, B; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Vermeulen, M; Voulot, D; Warr, N; Wenander, F; Wiens, A; De Witte, H; Wrzosek-Lipska, K

    2016-01-15

    Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

  4. 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.

  5. Passive vibro-acoustic detection of a sodium-water reaction in a steam generator of a sodium-cooled fast neutrons nuclear reactor by beam forming

    International Nuclear Information System (INIS)

    Moriot, Jeremy

    2013-01-01

    This thesis deals with a new method to detect a sodium-water reaction in a steam generator of a fast sodium-cooled nuclear reactor. More precisely, the objective is to detect a micro-leak of water (flow ≤ 1 g/s) in less than 10 seconds by measuring the external shell vibrations of the component. The strong background noise in operation makes impossible the use of a detection system based on a threshold overrun. A beam forming method applied to vibrations measured by a linear array of accelerometers is developed in this thesis to increase the signal-to-noise ratio and to detect and locate the leak in the steam generator. A numerical study is first realized. Two models are developed in order to simulate the signals measured by the accelerometers of the array. The performances of the beam forming are then studied in function of several parameters, such as the source location and frequency, the damping factor, the background noise considered. The first model consists in an infinite plate in contact with a heavy fluid, excited by an acoustic monopole located in this fluid. Analyzing the transverse displacements in the wavenumber domain is useful to establish a criterion to sample correctly the vibration field of the plate. A second model, more representative of the system is also proposed. In this model, an elastic infinite cylindrical shell, filled with a heavy fluid is considered. The finite dimensions in the radial and circumferential directions lead to a modal behavior of the system which impacts the beam forming. Finally, the method is tested on an experimental mock-up which consists in a cylindrical pipe made in stainless steel and filled with water connected to hydraulic circuit. The water flow speed can be controlled by varying the speed of the pump. The acoustic source is generated by a hydro-phone. The performances of the beam forming are studied for different water flow speeds and different amplitude and frequencies of the source. (author) [fr

  6. 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)

  7. First one-line mass measurements at SHIPTRAP and mass determinations of neutron-rich Fr and Ra isotopes at ISOLTRAP

    International Nuclear Information System (INIS)

    Rahaman, M.S.

    2005-01-01

    SHIPTRAP is an ion trap facility behind the velocity lter SHIP at GSI/Darmstadt. Its aim are precision studies of transuranium nuclides produced in a fusion reaction and separated by SHIP. The current set-up for high-precision mass measurements consists of three main functional parts: (i) a gas cell for stopping the energetic ions from SHIP, (ii) radiofrequency quadrupole structures to cool and to bunch the ions extracted from the gas cell, and (iii) a superconducting magnet with two cylindrical Penning traps at a eld strength of 7 T. In this work the Penning trap system has been installed and extensively characterized. The rst on-line mass measurements of short-lived nuclides were carried out and the masses of 147 Er and 148 Er could be experimentally determined for the rst time. Here a relative mass uncertainty of δm/m of about 1 x 10 -6 was achieved. Furthermore the masses of heavy neutron-rich 229-232 Ra and 230 Fr isotopes have been determined with a relative mass uncertainty of about 1 x 10 -7 with the ISOLTRAP mass spectometer at ISOLDE/CERN. The isotope 232 Ra is the heaviest unstable nuclide ever investigated with a Penning trap. Underlying nuclear structure effects of these nuclides far from β-stability were studied by a comparison of the resulting two-neutron separation energies S 2n with those given by the theoretical Infinite Nuclear Mass model. (orig.)

  8. A study of some neutron-rich isotopes of lanthanum, cerium and praseodymium by means of fast chemical on-line separation technique SISAK

    International Nuclear Information System (INIS)

    Skarnemark, G.

    1977-01-01

    The fast on-line chemical separation technique SISAK has been utilized to study the decay properties of neutron-rich isotopes of La, Ce and Pr. The results include partial decay schemes and γ-ray intensity data for 14 min 143 La, 42 s 144 La, 25 s 145 La, 9 s 146 La, 3 min 145 Ce, 14 min 146 Ce, 56 s 147 Ce, 50 s 148 Ce, 12 min 147 Pr, 2 min 148 Pr, 3 min 149 Pr and 6 s 150 Pr. Half-lives and γ-ray energies are reported for the previously unknown nuclides 147 La (Tsub(1/2) = 2.2 s), 148 La (Tsub(1/2) approximately 1 s), 149 Ce (Tsub(1/2) = 5.7 s) and 150 Ce (Tsub(1/2) = 4.1 s). The nuclides were formed in thermal neutron-induced fission of 235 U. The fission products were transferred to the SISAK system via a gas jet recoil transportation (GJRT) system. The combination of the GJRT system with SISAK is discussed, as well as the chemical separation systems used for the isolation of La, Ce and Pr. The appendices I - IX contain previously published material which is included in the thesis. (Auth.)

  9. 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...

  10. Neutronics and thermal-hydraulics coupling: some contributions toward an improved methodology to simulate the initiating phase of a severe accident in a sodium fast reactor

    International Nuclear Information System (INIS)

    Guyot, Maxime

    2014-01-01

    This project is dedicated to the analysis and the quantification of bias corresponding to the computational methodology for simulating the initiating phase of severe accidents on Sodium Fast Reactors. A deterministic approach is carried out to assess the consequences of a severe accident by adopting best estimate design evaluations. An objective of this deterministic approach is to provide guidance to mitigate severe accident developments and re-criticalities through the implementation of adequate design measures. These studies are generally based on modern simulation techniques to test and verify a given design. The new approach developed in this project aims to improve the safety assessment of Sodium Fast Reactors by decreasing the bias related to the deterministic analysis of severe accident scenarios. During the initiating phase, the subassembly wrapper tubes keep their mechanical integrity. Material disruption and dispersal is primarily one-dimensional. For this reason, evaluation methodology for the initiating phase relies on a multiple-channel approach. Typically a channel represents an average pin in a subassembly or a group of similar subassemblies. In the multiple-channel approach, the core thermal-hydraulics model is composed of 1 or 2 D channels. The thermal-hydraulics model is coupled to a neutronics module to provide an estimate of the reactor power level. In this project, a new computational model has been developed to extend the initiating phase modeling. This new model is based on a multi-physics coupling. This model has been applied to obtain information unavailable up to now in regards to neutronics and thermal-hydraulics models and their coupling. (author) [fr

  11. 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)

  12. Evaluation of sodium-23 neutron capture cross section data for the ENDF/B V-III file

    International Nuclear Information System (INIS)

    Paik, N.C.; Pitterle, T.A.

    1975-01-01

    The evaluation of neutron cross sections of 23 Na, material number 1156, for the ENDF/B File is described. Cross sections were evaluated between 10 -5 eV and 15 MeV. Experimental data available up to March 1971 were included in the evaluation

  13. Precision mass measurements of very short-lived, neutron-rich Na isotopes using a radiofrequency spectrometer

    CERN Document Server

    Lunney, M D; Doubre, H; Henry, S; Monsanglant, C; De Saint-Simon, M; Thibault, C; Toader, C F; Borcea, C; Bollen, G

    2001-01-01

    Mass measurements of high precision have been performed on sodium isotopes out to $^{30}$Na using a new technique of radiofrequency excitation of ion trajectories in a homogeneous magnetic field. This method, especially suited to very short-lived nuclides, has allowed us to significantly reduce the uncertainty in mass of the most exotic Na isotopes: a relative error of 5x10$^{-7}$ was achieved for $^{28}$Na having a half-life of only 30.5 ms and 9x10$^{-7}$ for the weakly produced $^{30}$Na. Verifying and minimizing binding energy uncertainties in this region of the nuclear chart is important for clarification of a long standing problem concerning the strength of the $N$=20 magic shell closure. These results are the fruit of the commissioning of the new experimental program Mistral.

  14. 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)

  15. Potent effects of alkaloid-rich extract from Huperzia selago against sodium nitroprusside-evoked PC12 cells damage via attenuation of oxidative stress and apoptosis

    Directory of Open Access Journals (Sweden)

    Anna Magdalena Lenkiewicz

    2016-06-01

    Full Text Available Imbalance between production and scavenging of free radicals and other reactive oxygen species (ROS is a component of many diseases, but it is especially important in aging-related diseases of the central nervous system. Oxidative stress-induced neuronal dysfunction plays an important role in the pathomechanism of neurodegenerative disorders, including Alzheimer’s and Parkinson’s disease. Experimental data showed that free radical scavengers may protect the brain against oxidative modifications. The need for efficient and safe antioxidants with therapeutic potential stimulated the rise of interest in the medicinal plant products, which are a rich source of phytochemicals possessing biological activity. In our studies we focused on alkaloid fractions (AFs isolated from club moss, Huperzia selago and Diphasiastrum complanatum, due to their beneficial activity and exclusive chemical structure. Our previous study demonstrated that selected alkaloids from Huperzia selago effectively protect macromolecules from oxidative damage. Therefore, in the present study we investigated the effects and mechanisms of action of AFs isolated from Huperzia selago and Diphasiastrum complanatum against sodium nitroprusside (SNP-induced oxidative injury in PC12 cells. The results demonstrated that the selected AFs via reduction of nitric oxide (NO liberation protected cells against oxidative stress, DNA and mitochondrial damage, as well as apoptosis caused by SNP. Selected AF notably decreased SNP-evoked mitochondrial polymerase γ (Polg up-regulation. Furthermore, AF which contains Lycopodine, Serratidine, Lycoposerramine-G and (probably Cermizine B completely inhibited the SNP-induced expression of interferon-γ (Ifng and cyclooxygenase 2 (Ptgs2 as well as significantly down-regulated the expression of 12/15-lipoxygenase (Alox12 and tended to decrease the mRNA level of interleukin-6 gene (Il6. In conclusion, these results suggest that the AFs from Huperzia selago

  16. Europium and sodium co-doped LiCaAlF.sub.6./sub. scintillator for neutron detection

    Czech Academy of Sciences Publication Activity Database

    Yanagida, T.; Yamaji, A.; Kawaguchi, N.; Fujimoto, Y.; Fukuda, K.; Kurosawa, S.; Yamazaki, A.; Watanabe, K.; Futami, Y.; Yokota, Y.; Uritani, A.; Iguchi, T.; Yoshikawa, A.; Nikl, Martin

    2011-01-01

    Roč. 4, č. 10 (2011), 106401/1-106401/3 ISSN 1882-0778 Grant - others:GA AV ČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : fluoride * single crystal * scintillator * neutron detection * Eu 2+ center Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.013, year: 2011 http://apex.jsap.jp/link?APEX/4/106401/

  17. Spins, charge radii and magnetic moments of neutron-rich Mn isotopes measured with bunched beam Collinear Laser Spectroscopy

    CERN Document Server

    AUTHOR|(CDS)2085887; Heylen, Hanne

    In this work, the odd-even $^{51–63}$Mn isotopes have been analyzed using collinear laser spectroscopy, from which the magnetic dipole moment and the change in change in mean square charge radius can be determined. The magnetic moment is very sensitive to the composition of the total nuclear wave function, while the charge radius gives information about the relative size and degree of deformation of the nucleus. An additional advantage of collinear laser spectroscopy is the possibility of direct measurement of the nuclear spin. The main motivation behind the study of these isotopes is to investigate the change in nuclear structure when approaching neutron number N = 40. This region is of interest due to the apparent doubly magic nature of $^{68}$Ni , which is not seen in the N = 40 isotopes of $^{26}$Fe and $^{24}$Cr. Mn, situated between these elements, offers another perspective due to its uncoupled proton. Based on the observed spectra and extracted moments, spins were assigned to $^{59,61,63}$Mn. The ex...

  18. Transition probabilities in neutron-rich Se,8280 and the role of the ν g9 /2 orbital

    Science.gov (United States)

    Litzinger, J.; Blazhev, A.; Dewald, A.; Didierjean, F.; Duchêne, G.; Fransen, C.; Lozeva, R.; Verney, D.; de Angelis, G.; Bazzacco, D.; Birkenbach, B.; Bottoni, S.; Bracco, A.; Braunroth, T.; Cederwall, B.; Corradi, L.; Crespi, F. C. L.; Désesquelles, P.; Eberth, J.; Ellinger, E.; Farnea, E.; Fioretto, E.; Gernhäuser, R.; Goasduff, A.; Görgen, A.; Gottardo, A.; Grebosz, J.; Hackstein, M.; Hess, H.; Ibrahim, F.; Jolie, J.; Jungclaus, A.; Kolos, K.; Korten, W.; Leoni, S.; Lunardi, S.; Maj, A.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Mijatovic, T.; Million, B.; Möller, O.; Modamio, V.; Montagnoli, G.; Montanari, D.; Morales, A. I.; Napoli, D. R.; Niikura, M.; Pietralla, N.; Pollarolo, G.; Pullia, A.; Quintana, B.; Recchia, F.; Reiter, P.; Rosso, D.; Sahin, E.; Salsac, M. D.; Scarlassara, F.; Söderström, P.-A.; Stefanini, A. M.; Stezowski, O.; Szilner, S.; Theisen, Ch.; Valiente-Dobón, J. J.; Vandone, V.; Vogt, A.

    2018-04-01

    Transition probabilities of intermediate-spin yrast and non-yrast excitations in Se,8280 were investigated in a recoil distance Doppler-shift (RDDS) experiment performed at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. The Cologne Plunger device for deep inelastic scattering was used for the RDDS technique and was combined with the AGATA Demonstrator array for the γ -ray detection and coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In 80Se, the level lifetimes of the yrast (61+) and (81+) states and of a non-yrast band feeding the yrast 41+ state are determined. A spin and parity assignment of the head of this sideband is discussed based on the experimental results and supported by large-scale shell-model calculations. In 82Se, the level lifetimes of the yrast 61+ state and the yrare 42+ state and lifetime limits of the yrast (101+) state and of the 51- state are determined. Although the experimental results contain large uncertainties, they are interpreted with care in terms of large-scale shell-model calculations using the effective interactions JUN45 and jj44b. The excited states' wave functions are investigated and discussed with respect to the role of the neutron g9 /2 orbital.

  19. Relevance of a Hypersaline Sodium-Rich Naturally Sparkling Mineral Water to the Protection against Metabolic Syndrome Induction in Fructose-Fed Sprague-Dawley Rats: A Biochemical, Metabolic, and Redox Approach

    Directory of Open Access Journals (Sweden)

    Cidália Dionísio Pereira

    2014-01-01

    Full Text Available The Metabolic Syndrome increases the risk for atherosclerotic cardiovascular disease and type 2 Diabetes Mellitus. Increased fructose consumption and/or mineral deficiency have been associated with Metabolic Syndrome development. This study aimed to investigate the effects of 8 weeks consumption of a hypersaline sodium-rich naturally sparkling mineral water on 10% fructose-fed Sprague-Dawley rats (Metabolic Syndrome animal model. The ingestion of the mineral water (rich in sodium bicarbonate and with higher potassium, calcium, and magnesium content than the tap water used as control reduced/prevented not only the fructose-induced increase of heart rate, plasma triacylglycerols, insulin and leptin levels, hepatic catalase activity, and organ weight to body weight ratios (for liver and both kidneys but also the decrease of hepatic glutathione peroxidase activity and oxidized glutathione content. This mineral-rich water seems to have potential to prevent Metabolic Syndrome induction by fructose. We hypothesize that its regular intake in the context of modern diets, which have a general acidic character interfering with mineral homeostasis and are poor in micronutrients, namely potassium, calcium, and magnesium, could add surplus value and attenuate imbalances, thus contributing to metabolic and redox health and, consequently, decreasing the risk for atherosclerotic cardiovascular disease.

  20. Point defect dynamics in sodium aluminum hydrides - a combined quasielastic neutron scattering and density functional theory study

    DEFF Research Database (Denmark)

    Shi, Qing; Voss, Johannes; Jacobsen, H.S.

    2007-01-01

    we study hydrogen dynamics in undoped and TiCl3-doped samples of NaAlH4 and Na3AlH6 using a combination of density functional theory calculations and quasielastic neutron scattering. Hydrogen dynamics is found to be limited and mediated by hydrogen vacancies in both alanate phases, requiring......Understanding the catalytic role of titanium-based additives on the reversible hydrogenation of complex metal hydrides is an essential step towards developing hydrogen storage materials for the transport sector. Improved bulk diffusion of hydrogen is one of the proposed catalytic effects, and here...

  1. 18 Sco: A solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging

    Energy Technology Data Exchange (ETDEWEB)

    Meléndez, Jorge; Monroe, TalaWanda R.; Tucci Maia, Marcelo; Freitas, Fabrício C. [Departamento de Astronomia do IAG/USP, Universidade de São Paulo, Rua do Matão 1226, 05508-900 São Paulo, SP (Brazil); Ramírez, Iván [McDonald Observatory and Department of Astronomy, University of Texas at Austin (United States); Karakas, Amanda I.; Yong, David; Asplund, Martin [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Bedell, Megan; Bean, Jacob [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Bergemann, Maria [Institute of Astronomy, University of Cambridge, Madingley Road, CB3 0HA, Cambridge (United Kingdom); Do Nascimento, José-Dias Jr.; Castro, Matthieu [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Bazot, Michael [Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Alves-Brito, Alan, E-mail: jorge.melendez@iag.usp.br [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, Porto Alegre, RS (Brazil)

    2014-08-10

    We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R ∼ 110,000), high signal-to-noise ratio (800-1,000) Very Large Telescope UVES spectra, which allow us to achieve a precision of about 0.005 dex in differential abundances. The effective temperature and surface gravity of 18 Sco are T{sub eff} = 5823 ± 6 K and log g = 4.45 ± 0.02 dex, i.e., 18 Sco is 46 ± 6 K hotter than the Sun and log g is 0.01 ± 0.02 dex higher. Its metallicity is [Fe/H] = 0.054 ± 0.005 dex, and its microturbulence velocity is +0.02 ± 0.01 km s{sup –1} higher than solar. Our precise stellar parameters and differential isochrone analysis show that 18 Sco has a mass of 1.04 ± 0.02 M{sub ☉} and that it is ∼1.6 Gyr younger than the Sun. We use precise High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities to search for planets, but none are detected. The chemical abundance pattern of 18 Sco displays a clear trend with condensation temperature, thus showing higher abundances of refractories in 18 Sco than in the Sun. Intriguingly, there are enhancements in the neutron-capture elements relative to the Sun. Despite the small element-to-element abundance differences among nearby n-capture elements (∼0.02 dex), we successfully reproduce the r-process pattern in the Solar System. This is independent evidence for the universality of the r process. Our results have important implications for chemical tagging in our Galaxy and nucleosynthesis in general.

  2. Determination of platinum, palladium, iridium and gold on selected geological reference materials by radiochemical neutron activation analysis: comparison of procedures based on aqua regia leaching and sodium peroxide sintering

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A.; Figueiredo, A.M.G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-05-01

    A rapid and sensitive neutron activation method for the determination of platinum, palladium, iridium and gold in rocks is described. The procedure consists of thermal neutron irradiation of about 250 mg of sample, followed by chemical treatment of the rock, precipitation of gold and the platinum group elements with tellurium and high-resolution gamma-ray spectrometry with a hyper-pure Ge detector. Two different methods were used for the chemical treatment of the rock: aqua regia leaching and sintering with sodium peroxide. The procedures were evaluated by analysis of the certified reference material SARM-7 and the reference material CHR-Pt+. (author).

  3. Determination of platinum, palladium, iridium and gold on selected geological reference materials by radiochemical neutron activation analysis: comparison of procedures based on aqua regia leaching and sodium peroxide sintering

    International Nuclear Information System (INIS)

    Nogueira, C.A.; Figueiredo, A.M.G.

    1995-01-01

    A rapid and sensitive neutron activation method for the determination of platinum, palladium, iridium and gold in rocks is described. The procedure consists of thermal neutron irradiation of about 250 mg of sample, followed by chemical treatment of the rock, precipitation of gold and the platinum group elements with tellurium and high-resolution gamma-ray spectrometry with a hyper-pure Ge detector. Two different methods were used for the chemical treatment of the rock: aqua regia leaching and sintering with sodium peroxide. The procedures were evaluated by analysis of the certified reference material SARM-7 and the reference material CHR-Pt+. (author)

  4. Sodium borocaptate (BSH) for Boron Neutron Capture Therapy (BNCT) in the hamster cheek pouch oral cancer model: boron biodistribution at 9 post administration time-points

    International Nuclear Information System (INIS)

    Garabalino, M.A.; Heber, E.M.; Monti, Hughes A.; Molinari, A.J.; Pozzi, E.C.C.; Trivillin, V.A.; Schwint, Amanda E.

    2011-01-01

    The therapeutic success of Boron Neutron Capture Therapy (BNCT) depends centrally on boron concentration in tumor and healthy tissue. We previously demonstrated the therapeutic efficacy of boronophenylalanine (BPA) and sodium decahydrodecaborate (GB-10) as boron carriers for BNCT in the hamster cheek pouch oral cancer model. Given the clinical relevance of sodium mercaptoundecahydro-closo-dodecaborate (BSH) as a boron carrier, the aim of the present study was to expand the ongoing BSH biodistribution studies in the hamster cheek pouch oral cancer model. In particular, we studied 3 additional post-administration time-points and increased the sample size corresponding to the time-points evaluated previously, to select more accurately the post-administration time at which neutron irradiation would potentially confer the greatest therapeutic advantage. BSH was dissolved in saline solution in anaerobic conditions to avoid the formation of the dimer BSSB and its oxides which are toxic. The solution was injected intravenously at a dose of 50 mg 10 B/kg (88 mg BSH / kg). Different groups of animals were killed humanely at 7, 8, and 10 h after administration of BSH. The sample size corresponding to the time-points 3, 4, 6, 9 and 12 h was increased. Samples of blood, tumor, precancerous tissue, normal pouch tissue, cheek mucosa, parotid gland, palate, skin, tongue, spinal cord marrow, brain, liver, kidney, spleen and lung were processed for boron measurement by Optic Emission Spectroscopy (ICP-OES). Boron concentration in tumor peaked to 24-34 ppm, 3-10 h post-administration of BSH, with a spread in values that resembled that previously reported in other experimental models and human subjects. The boron concentration ratios tumor/normal pouch tissue and tumor/blood ranged from 1.3 to 1.8. No selective tumor uptake was observed at any of the time points evaluated. The times post-administration of BSH that would be therapeutically most useful would be 5, 7 and 9 h. The

  5. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    International Nuclear Information System (INIS)

    Kisohara, N.; Suzuki, H.; Akita, K.; Kasahara, N.

    2012-01-01

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  6. The dismantling of fast reactors: sodium processing

    International Nuclear Information System (INIS)

    Rodriguez, G.; Berte, M.; Serpante, J.P.

    1999-01-01

    Fast reactors require a coolant that does not slow down neutrons so water can not be used. Metallic sodium has been chosen because of its outstanding neutronic and thermal properties but sodium reacts easily with air and water and this implies that sodium-smeary components can not be considered as usual nuclear wastes. A stage of sodium neutralizing is necessary in the processing of wastes from fast reactors. Metallic sodium is turned into a chemically stable compound: soda, carbonates or sodium salts. This article presents several methods used by Framatome in an industrial way when dismantling sodium-cooled reactors. (A.C.)

  7. Identification and Decay Studies of New, Neutron-Rich Isotopes of Bismuth, Lead and Thallium by means of a Pulsed Release Element Selective Method

    CERN Multimedia

    Mills, A; Kugler, E; Van duppen, P L E; Lettry, J

    2002-01-01

    % IS354 \\\\ \\\\ It is proposed to produce, identify and investigate at ISOLDE new, neutron-rich isotopes of bismuth, lead and thallium at the mass numbers A=215 to A=218. A recently tested operation mode of the PS Booster-ISOLDE complex, taking an advantage of the unique pulsed proton beam structure, will be used together with a ThC target in order to increase the selectivity. The decay properties of new nuclides will be studied by means of $\\beta$-, $\\gamma$- and X- ray spectroscopy methods. The expected information on the $\\beta$-half-lives and excited states will be used for testing and developing the nuclear structure models ``south-east'' of $^{208}$Pb, and will provide input data for the description of the r-process path at very heavy nuclei. The proposed study of the yields and the decay properties of those heavy nuclei produced in the spallation of $^{232}$Th by a 1~GeV proton beam contributes also the data necessary for the simulations of a hybrid accelerator-reactor system.

  8. Beta- and gamma-decay studies of neutron-rich chromium, manganese, cobalt and nickel isotopes including the new isotopes 60Cr and 60gMn

    International Nuclear Information System (INIS)

    Bosch, U.; Schmidt-Ott, W.D.; Runte, E.; Tidemand-Petersson, P.; Koschel, P.; Meissner, F.; Kirchner, R.; Klepper, O.; Roeckl, E.; Rykaczewski, K.; Schardt, D.

    1987-10-01

    A 36 mg/cm 2 thick nat W target was irradiated with 11.5 MeV/u 76 Ge of 15 to 20 particle + nA beam intensity. On-line mass-separated samples of projectile-like neutron-rich products from multi-nucleon transfer-reactions were investigated in the region of mass 58-69 by β- and γ-ray spectroscopy. The new isotope 60 Cr was identified with a half-life of 0.57(6) s and for the 60 Mn ground-state a half-life value of 51(6) s was obtained. Decay schemes were constructed for 58 Cr, 58 Mn (t 1/2 = 3 s), 65,66,67 Co and 69 Ni. One new γ-ray was found in the decay of 59 Cr. The Q β -value of 66 Co was measured yielding 9.7(5) MeV. The comparison of the measured new β-half-life of 60 Cr with the most recent predictions gave again an enhancement of the experimental value. (orig.)

  9. First on-line mass measurements at SHIPTRAP and mass determinations of neutron-rich Fr and Ra isotopes at ISOLTRAP

    CERN Document Server

    Rahaman, Saidu

    SHIPTRAP is an ion trap facility behind the velocity filter SHIP at GSI/Darmstadt. Its aim are precision studies of transuranium nuclides produced in a fusion reaction and separated by SHIP. The current set-up for high-precision mass measurements consists of three main functional parts: (i) a gas cell for stopping the energetic ions from SHIP, (ii) radiofrequency quadrupole structures to cool and to bunch the ions extracted from the gas cell, and (iii) a superconducting magnet with two cylindrical Penning traps at a field strength of 7 T. In this work the Penning trap system has been installed and extensively characterized. The first on-line mass measurements of short-lived nuclides were carried out and the masses of $^{147}$Er and $^{148}$Er could be experimentally determined for the first time. Here a relative mass uncertainty of $\\delta$ m/m of about 1$\\times$ 10$^{-6}$ was achieved. Furthermore the masses of heavy neutron-rich $^{229-232}$Ra and $^{230}$Fr isotopes have been determined with a relative m...

  10. Octupole correlations in neutron-rich {sup 143,145}Ba and a type of superdeformed band in {sup 145}Ba

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, S.J.; Wang, M.G.; Long, G.L.; Zhu, L.Y.; Gan, C.Y.; Yang, L.M.; Sakhaee, M.; Li, M.; Deng, J.K. [Physics Department, Tsinghua University, Beijing 100084, Peoples Republic of (China); Zhu, S.J.; Hamilton, J.H.; Ramayya, A.V.; Jones, E.F.; Hwang, J.K.; Zhang, X.Q.; Gore, P.M.; Peker, L.K.; Drafta, G.; Babu, B.R.; Deng, J.K.; Ginter, T.N.; Beyer, C.J.; Kormicki, J.; Ter-Akopian, G.M.; Daniel, A.V. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Zhu, S.J.; Ter-Akopian, G.M.; Daniel, A.V. [Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 (United States); Ma, W.C. [Physics Department, Mississippi State University, Mississippi 39762 (United States); Cole, J.D.; Aryaeinejad, R.; Drigert, M.W. [Idaho National Engineering Laboratory, Idaho Falls, Idaho 83415 (United States); Rasmussen, J.O.; Asztalos, S.; Lee, I.Y.; Macchiavelli, A.O.; Chu, S.Y.; Gregorich, K.E.; Mohar, M.F. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ter-Akopian, G.M.; Daniel, A.V.; Oganessian, Y.T.; Kliman, J. [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russia); Donangelo, R. [Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RG (Brazil); Stoyer, M.A.; Lougheed, R.W.; Moody, K.J.; Wild, J.F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Prussin, S.G. [Nuclear Engineering Department, University of California at Berkeley, Berkeley, California 94720 (United States); Kliman, J. [Institute of Physics, SASc, Dubravskacesta 9, 84228 Bratislava (Slovakia); Griffin, H.C. [University of Michigan, Ann Arbor, Michigan 48104 (United States)

    1999-11-01

    High spin states in neutron-rich odd-{ital Z} {sup 143,145}Ba nuclei have been investigated from the study of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf by using {gamma}-{gamma}- and {gamma}-{gamma}-{gamma}- coincidence techniques. Alternating parity bands are identified for the first time in {sup 145}Ba and extended in {sup 143}Ba. A new side band, with equal, constant dynamic, and kinetic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in {sup 145}Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in {sup 143}Ba and in {sup 145}Ba. These collective bands show competition and coexistence between symmetric and asymmetric shapes in {sup 145}Ba. Evidence is found for crossing M1 and E1 transitions between the s=+i and s={minus}i doublets in {sup 143}Ba. {copyright} {ital 1999} {ital The American Physical Society}

  11. Evaluation of hypoxia-specific cytotoxic bioreductive agent-sodium borocaptate-10B conjugates as 10B-carriers in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Masunaga, Shin-ichiro; Nagasawa, Hideko; Gotoh, Keiko

    2006-01-01

    The purpose of this study was to evaluate the usefulness of 5 new 10 B-compounds (TX-2091, TX-2095, TX-2097, TX-2100, and TX-2110) as 10 B-carriers in boron neutron capture therapy (BNCT). They were conjugates that had been synthesized from a hypoxia-specific cytotoxic bioreductive agent, quinoxaline oxide TX-402, and a clinically used 10 B-carrier, sodium borocaptate- 10 B (BSH). The 5 new compounds were hybrid compounds that have both a hypoxic cytotoxin unit and a thermal neutron-sensitizing unit, BSH. These new compounds and BSH were administered intraperitoneally to SCC VII tumor-bearing mice. Then, the 10 B concentrations in the tumors and normal tissues were measured by γ-ray spectrometry. Subsequently, SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, then treated with TX-2100, which was chosen based on the results of the above-mentioned biodistribution analyses, or BSH in the same manner as in the biodistribution studies. Right after irradiation, during which intratumor 10 B concentrations were kept at levels similar to each other, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling [=quiescent (Q) cells] was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in the total (P+Q) tumor cell population was determined from the tumors that were not pretreated with BrdU. Clonogenic cell survival was also determined in mice given no BrdU. 10 B biodistribution analyses in tumors, brain, skin, muscles, blood, and liver indicated that TX-2100 has the most favorable characteristics for concentrating a sufficient amount of 10 B in tumors and maintaining a high enough 10 B concentration during irradiation. In addition, TX-2100 had a significantly stronger radio-sensitizing effect with

  12. Comparison calculation of a large sodium-cooled fast breeder reactor using the cell code MICROX-2 in connection with ENDF/B-VI and JEF-1.1 neutron data

    International Nuclear Information System (INIS)

    Pelloni, S.

    1992-02-01

    We have obtained results for a large sodium-cooled fast breeder reactor benchmark using data from the ENDF/B-VI and from Revision 1 of the JEF-1 (JEF-1.1) evaluation. The required cross sections were processed with the NJOY code system (Version 89.62) and homogenized with the spectrum cell code MICROX-2. Multigroup transport-theory calculations in 33 neutron groups (forward and adjoint) were performed using the two-dimensional code TWODANT and kinetic parameters were determined using the first-order perturbation-theory code PERT-V. We calculated eigenvalues, neutron balance data, global and regional breeding and conversion ratios, central rate ratios and reactivity worths with and without sodium, effective delayed neutron fraction and inhour reactivity, regional sodium void reactivity, and isothermal core fuel Doppler-reactivities. In particular, it is shown that good agreement (generally within one standard deviation) is achieved between these results and the average values over sixteen benchmark solutions obtained in the past. The eigenvalues predicted with ENDF/B-VI are up to 0.7% larger than those calculated with JEF-1.1 cross sections. This discrepancy is mainly due to different inelastic scattering cross sections for 23 Na and 238 U, and to different fast fission and nubar data for 239 Pu. (author) 5 figs., 30 tabs., 24 refs

  13. Effects of bulk colloidal stability on adsorption layers of poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate at the air-water interface studied by neutron reflectometry.

    Science.gov (United States)

    Campbell, Richard A; Yanez Arteta, Marianna; Angus-Smyth, Anna; Nylander, Tommy; Varga, Imre

    2011-12-29

    We show for the oppositely charged system poly(diallyldimethylammonium chloride)/sodium dodecyl sulfate that the cliff edge peak in its surface tension isotherm results from the comprehensive precipitation of bulk complexes into sediment, leaving a supernatant that is virtually transparent and a depleted adsorption layer at the air/water interface. The aggregation and settling processes take about 3 days to reach completion and occur at bulk compositions around charge neutrality of the complexes which lack long-term colloidal stability. We demonstrate excellent quantitative agreement between the measured surface tension values and a peak calculated from the surface excess of surfactant in the precipitation region measured by neutron reflectometry, using the approximation that there is no polymer left in the liquid phase. The nonequilibrium nature of the system is emphasized by the production of very different interfacial properties from equivalent aged samples that are handled differently. We go on to outline our perspective on the "true equilibrium" state of this intriguing system and conclude with a comment on its practical relevance given that the interfacial properties can be so readily influenced by the handling of kinetically trapped bulk aggregates. © 2011 American Chemical Society

  14. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    Energy Technology Data Exchange (ETDEWEB)

    Putra, Edy Giri Rachman [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Patriati, Arum [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Gadjah Mada, Bulaksumur, Yogyakarta 55281, Indonesia giri@batan.go.id (Indonesia)

    2015-04-16

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

  15. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Patriati, Arum

    2015-01-01

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations

  16. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

    2016-01-01

    Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

  17. Detailed neutronic study of the power evolution for the European Sodium Fast Reactor during a positive insertion of reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Facchini, A.; Giusti, V.; Ciolini, R. [Department of Civil and Industrial Engineering (DICI), University of Pisa, Largo Lucio Lazzarino 2, I-56126 Pisa (Italy); Tuček, K.; Thomas, D. [Joint Research Centre, Institute for Energy and Transport (JRC - IET), European Commission, P.O. Box 2, NL-1755 ZG Petten (Netherlands); D' Agata, E., E-mail: elio.dagata@ec.europa.eu [Joint Research Centre, Institute for Energy and Transport (JRC - IET), European Commission, P.O. Box 2, NL-1755 ZG Petten (Netherlands)

    2017-03-15

    Highlights: • This paper studies the effect of an unexpected runway of a control rod in the ESFR. • The power peaked fuel pin within the core was identified. • The increase of the fission power density of the fuel pin has been evaluated. • Radial/axial fission power density of the power peaked fuel pin has been evaluated. - Abstract: The new reactor concepts proposed in the Generation IV International Forum require the development and validation of new components and new materials. Inside the Collaborative Project on the European Sodium Fast Reactor, several accidental scenario have been studied. Nevertheless, none of them coped with mechanical safety assessment of the fuel cladding under accidental conditions. Among the accidental conditions considered, there is the unprotected transient of overpower (UTOP), due to the insertion, at the end of the first fuel cycle, of a positive reactivity into the reactor core as a consequence of the unexpected runaway of one control rod. The goal of the study was the search for a detailed distribution of the fission power, in the radial and axial directions, within the power peaked fuel pin under the above accidental conditions. Results show that after the control rod ejection an increase from 658 W/cm{sup 3} to 894 W/cm{sup 3}, i.e. of some 36%, is expected for the power peaked fuel pin. This information will represent the base to investigate, in a future work, the fuel cladding safety margin.

  18. 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)

  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. Effect of a Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A Small-angle Neutron Scattering Study

    International Nuclear Information System (INIS)

    Arum Patriati; Edy Giri Rachman Putra

    2009-01-01

    The effect of different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH 3 (CH 2 ) 10 COOH and hexadecanoic acid, CH 3 (CH 2 ) 14 COOH as a co-surfactant in the 0.3M SDS micellar solution has been studied using small angle neutron scattering (SANS). Here, the present of dodecanoic acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 21.7 Armstrong to 35.5 Armstrong at a fixed minor axis of 16.7 Armstrong in the present of 0.005M to 0.1M dodecanoic acid. Nevertheless, this effect was not shown in the present of hexadecanoic acid with the same concentration range. The present of hexadecanoic acid molecules gave a small effect on growth of SDS micelles where the major axis of the micelle was simply elongated from 21.5 Armstrong to 23.5 Armstrong. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules is one of the determining factors in forming a mixed micelles structure. (author)

  1. Determination of the sodium, aluminium, potassium, manganese, magnesium, bromine, cadmium and chlorine concentration values in the whole blood samples of human cancer using neutron activation analysis facility of the second Egyptian research reactor

    Directory of Open Access Journals (Sweden)

    N. F. Soliman

    2010-06-01

    Full Text Available Neutron activation analysis (NAA using the Second Egyptian Research Reactor (ETRR-2 has been utilized to analyze whole blood samples. The National Cancer Institute of Egypt provided us with 18 blood samples (11 breast, 2 prostate, 2 colon, 1 pancreatic, 1 ovarian and a random sample of normal person to estimate the concentration values of Sodium, Aluminium, Potassium, Manganese, Magnesium, Bromine, Chlorine. The pneumatic irradiation rabbit system (PIRS built in the vertical thermal column of the ETRR-2 reactor is used for short time irradiation at constant power. Elemental concentrations were estimated from measurements of the gamma-ray spectra of the product short lived isotopes in the samples. The calculated thermal to epithermal neutron flux ratio was found to be 196 at irradiation position. The tabulated concentrations were calculated by using k0-neutron activation analysis (k0NAA standardization method.

  2. Comparison of three experimental protocols in pre clinical studies for thyroid cancer treatment using sodium butyrate in combination with boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Perona, M; Rodriguez, C; Carpano, M; Majdalani E; Nievas, S; Olivera, M; Pisarev, M; Cabrini, R; Juvenal, G; Dagrosa A

    2012-01-01

    Background: We have shown that boron neutron capture therapy (BNCT) could be an alternative for the treatment of poorly differentiated (PDTC) and undifferentiated thyroid carcinoma (UTC). However new strategies are being assayed in order to optimize its application. Histone de acetylase inhibitors (HDAC-I) like sodium butyrate (NaB), are emerging as a new class of chemotherapeutic agents which target the epigenome. Since histone hyper acetylation mediates changes in chromatin conformation, HDAC-I are involved in different epigenetically controlled activities like apoptosis, proliferation, cell differentiation, induction of cell cycle arrest and motility. The purpose of the present studies was to analyze different treatment regimens of combination of NaB and boronophenylalanine (BPA) uptake in animals bearing transplants of a human thyroid carcinoma Methods: NIH nude mice of 6-8 weeks were implanted (s.c.) with 10 6 of human follicular thyroid carcinoma cells (WRO). Three regimens were evaluated in 48 animals after 15 days when tumors had a size between 50 and 100 mm 3 . Group 1 (n=10): BPA and NaB (50 mM) via i.p. at a dose of 110 mg/kg b.w. 24 h before boron compound administration; group 2 (n=10): BPA and NaB 3.4% in the water ad libitum during a month after 15 days post-implantation; group 3 (n=10): BPA alone. In all the groups BPA was injected at a dose of 350 mg/Kg b.w. (i.p.) and the animals were sacrificed at 2 h post-administration. Boron measurements in tissues and blood were performed by ICP-OES. A control group without NaB (n=6) for each regimen was included. The tumor growth and the body weight were determined twice a week during a month. Results: The administration of NaB 3.4% during a month previous to BNCT did not modify the body weight of the mice and decreased the tumor growth compared to its control group (p<0.01). The biodistribution studies showed a tumor boron concentration of 32.6 ± 1.4 ppm for group 1 (NaB 50 mM plus BPA), of 16.9 ± 3.7 ppm

  3. Single-particle states in neutron-rich 69,71Cu by means of the (d,3He) transfer reaction

    International Nuclear Information System (INIS)

    Morfouace, Pierre

    2014-01-01

    In two (d, 3 He) transfer reactions with MUST2 at GANIL and the split-pole at Orsay, we have determined the position of the proton-hole states in the neutron-rich 71 Cu (N=42) and 69 Cu (N=40) isotopes. We have found that in 71 Cu the hole strength of the f7/2 orbital lies at higher excitation energies than expected. From beta-decay and laser spectroscopy, the f5/2 first excited particle state in these isotopes was known to come down rapidly in energy when passing N=40 and even become the ground state in 75 Cu. This sudden energy shift has been explained in a number of theoretical works. The prediction for the f7/2 spin-orbit partner was that it would change in energy too through a related effect. Experimentally, the f7/2 proton-hole state is not known for N≥40. In 71 Cu two 7/2- states around 1 MeV are candidates to be a proton-hole. The experiment at GANIL took place in March 2011. A secondary beam of 72 Zn at 38 AMeV was produced by fragmentation and purified through the LISE spectrometer. The transfer reaction in inverse kinematics was studied with the MUST2 detectors plus four 20 micrometer silicon detector to identified the 3 He of low kinetic energy. The excitation spectrum of 71 Cu was reconstruct thanks to the missing mass method and the angular distributions were extracted and compared with a reaction model using the DWUCK4 and DWUCK5 code. From this work no states have been populated around 1 MeV concluding that the centroid of the f7/2 lies at higher excitation energy. We then remeasured the single-particle strength in 69 Cu in the corresponding (d, 3 He) reaction at Orsay in March 2013 in order to extend the existing data where 60% of the f7/2 strength is missing and make sure that there is a consistent analysis of spectroscopic factors between both isotopes in order to well understood and well quantify the evolution of the f7/2 orbital when we start filling the g9/2 orbital. In this second experiment we have performed the reaction in direct

  4. 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)

  5. Nuclear structure of neutron rich gallium, germanium and arsenic around N=50 and development of a laser ion source at ALTO

    International Nuclear Information System (INIS)

    Tastet, B.

    2011-01-01

    During this thesis, we have studied β decays of gallium's nuclei around N=50 and prepared a laser ionization source at ALTO.The production of exotic isotopes has brought new beam production challenges. The one addressed here relates to the elimination of isobar contaminants that create background for experiments. To address this issue a laser ionization source has been developed at ALTO. Copper has been chosen to be the first element to be ionized for physical interests and to compare the results of the laser ionization source with the ones at others facilities. A laser setup has been installed and optimized in order to ionize selectively the atoms of copper produced for experiments. After the optimization, a test of ionization of stable-copper was performed. This test has shown us that the laser system is able to successfully ionize atoms of copper.The studies of the region of the neutron-rich nuclei around N=50 are still to complete. 79,80,82,83,84,85 Ga has been produced using photo-nuclear reactions at the experimental area of the on-line PARRNe mass-separator operating with the ALTO facility. The fission fragments are produced at the interaction of the 50 MeV electron beam delivered by the ALTO linear accelerator with a thick target of uranium in a standard UC x form. The oven is connected to a W ionizer heated up to 2000 C degrees that selectively ionizes alkalis but also elements with low ionization potentials such as Ga. The ions are accelerated through 30 kV and magnetically mass-separated before being implanted on a mylar tape close to the detection setup, so that this system allows us to study β and β-n decays of 79,80,82,83,84,85 Ga.The data analysis have produced new results concerning the decays of 80 Ga, 84 Ga and 84 Ge. For 80 Ga, the existence of an isomeric state has been confirmed and two different half-lives were measured for the ground state and the isomer. Furthermore, the analysis of 84 Ga decay confirmed two states and allowed us to

  6. Sodium purification in Rapsodie

    International Nuclear Information System (INIS)

    Giraud, B.

    1968-01-01

    This report is one of a series of publications presenting the main results of tests carried out during the start-up of the first french fast neutron reactor: Rapsodie. The article presents the sodium purification techniques used in the reactor cooling circuits both from the constructional point of view and with respect to results obtained during the first years working. (author) [fr

  7. Improvement the value of sodium void reactivity effect of the fast neutron reactor by the instrumentality of the Monte Carlo code

    OpenAIRE

    P.A. Maslov; V.I. Matveev; I.V. Malysheva

    2015-01-01

    To fulfill safety of fast sodium reactors in a beyond design-basis accident (BDBA) like unprotected loss of flow accident (ULOF), the sodium void reactivity effect (SVRE) should be close to zero. Its value depends on the fuel burnup – the higher burnup the higher value of SVRE. We analyze limitation of the fuel burnup in the core of a large sodium reactor imposed by SVRE. The model of a large sodium-cooled reactor core is chosen for analysis. Two fuel types are considered – MOX and nitride...

  8. Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na{sub 3}OBr and Na{sub 4}OI{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yonggang, E-mail: yyggwang@gmail.com, E-mail: yangwg@hpstar.ac.cn, E-mail: yusheng.zhao@unlv.edu [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154 (United States); Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006 (China); High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); Wen, Ting [Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006 (China); Park, Changyong; Kenney-Benson, Curtis [High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); Pravica, Michael; Zhao, Yusheng, E-mail: yyggwang@gmail.com, E-mail: yangwg@hpstar.ac.cn, E-mail: yusheng.zhao@unlv.edu [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154 (United States); Yang, Wenge, E-mail: yyggwang@gmail.com, E-mail: yangwg@hpstar.ac.cn, E-mail: yusheng.zhao@unlv.edu [High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China)

    2016-01-14

    The structure stability under high pressure and thermal expansion behavior of Na{sub 3}OBr and Na{sub 4}OI{sub 2}, two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na{sub 3}OBr and Na{sub 4}OI{sub 2}, respectively. The cubic Na{sub 3}OBr structure and tetragonal Na{sub 4}OI{sub 2} with intergrowth K{sub 2}NiF{sub 4} structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na{sub 4}OI{sub 2} exhibits nearly isotropic compressibility. Negative thermal expansion was observed at low temperature range (20–80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications.

  9. Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na3OBr and Na4OI2

    International Nuclear Information System (INIS)

    Wang, Yonggang; Wen, Ting; Park, Changyong; Kenney-Benson, Curtis; Pravica, Michael; Zhao, Yusheng; Yang, Wenge

    2016-01-01

    The structure stability under high pressure and thermal expansion behavior of Na 3 OBr and Na 4 OI 2 , two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na 3 OBr and Na 4 OI 2 , respectively. The cubic Na 3 OBr structure and tetragonal Na 4 OI 2 with intergrowth K 2 NiF 4 structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na 4 OI 2 exhibits nearly isotropic compressibility. Negative thermal expansion was observed at low temperature range (20–80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications

  10. Penning-trap mass spectrometry of radioactive, highly charged ions. Measurements of neutron-rich Rb and Sr nuclides for nuclear astrophysics and development of a novel Penning trap for cooling highly charged ions

    International Nuclear Information System (INIS)

    Simon, Vanessa Veronique

    2012-01-01

    High-precision atomic mass measurements are vital for the description of nuclear structure, investigations of nuclear astrophysical processes, and tests of fundamental symmetries. The neutron-rich A ∼ 100 region presents challenges for modeling the astrophysical r-process because of sudden nuclear shape transitions. This thesis reports on high-precision masses of short-lived neutron-rich 94,97,98 Rb and 94,97-99 Sr isotopes using the TITAN Penning-trap mass spectrometer at TRIUMF. The isotopes were charge-bred to q = 15+; uncertainties of less than 4 keV were achieved. Results deviate by up to 11σ compared to earlier measurements and extend the region of nuclear deformation observed in the A∼100 region. A parameterized r-process model network calculation shows that mass uncertainties for the elemental abundances in this region are now negligible. Although beneficial for the measurement precision, the charge breeding process leads to an increased energy spread of the ions on the order of tens of eV/q. To eliminate this drawback, a Cooler Penning Trap (CPET) has been developed as part of this thesis. The novel multi-electrode trap structure of CPET forms nested potentials to cool HCI sympathetically using either electrons or protons to increase the overall efficiency and precision of the mass measurement. The status of the off-line setup and initial commissioning experiments are presented.

  11. Validation and Comparison of the Therapeutic Efficacy of Boron Neutron Capture Therapy Mediated By Boron-Rich Liposomes in Multiple Murine Tumor Models

    Directory of Open Access Journals (Sweden)

    Charles A Maitz

    2017-08-01

    Full Text Available Boron neutron capture therapy (BNCT was performed at the University of Missouri Research Reactor in mice bearing CT26 colon carcinoma flank tumors and the results were compared with previously performed studies with mice bearing EMT6 breast cancer flank tumors. Mice were implanted with CT26 tumors subcutaneously in the caudal flank and were given two separate tail vein injections of unilamellar liposomes composed of cholesterol, 1,2-distearoyl-sn-glycer-3-phosphocholine, and K[nido-7-CH3(CH215–7,8-C2B9H11] in the lipid bilayer and encapsulated Na3[1-(2`-B10H9-2-NH3B10H8] within the liposomal core. Mice were irradiated 30 hours after the second injection in a thermal neutron beam for various lengths of time. The tumor size was monitored daily for 72 days. Despite relatively lower tumor boron concentrations, as compared to EMT6 tumors, a 45 minute neutron irradiation BNCT resulted in complete resolution of the tumors in 50% of treated mice, 50% of which never recurred. Median time to tumor volume tripling was 38 days in BNCT treated mice, 17 days in neutron-irradiated mice given no boron compounds, and 4 days in untreated controls. Tumor response in mice with CT26 colon carcinoma was markedly more pronounced than in previous reports of mice with EMT6 tumors, a difference which increased with dose. The slope of the dose response curve of CT26 colon carcinoma tumors is 1.05 times tumor growth delay per Gy compared to 0.09 times tumor growth delay per Gy for EMT6 tumors, indicating that inherent radiosensitivity of tumors plays a role in boron neutron capture therapy and should be considered in the development of clinical applications of BNCT in animals and man.

  12. Control of sodium fires and sodium-water reactions in breeder reactors

    International Nuclear Information System (INIS)

    Foerster, K.; Ruloff, G.; Voss, J.

    1985-01-01

    The excellent neutronic and thermodynamic properties of sodium as a fast-reactor coolant are somewhat counterbalanced by its high oxygen affinity. Because incidents like sodium fires and sodium-water reactions cannot be absolutely excluded, their effects and preventive measures have to be investigated. Characteristics and counter-measures are discussed. (orig.) [de

  13. Sodium cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hokkyo, N; Inoue, K; Maeda, H

    1968-11-21

    In a sodium cooled fast neutron reactor, an ultrasonic generator is installed at a fuel assembly hold-down mechanism positioned above a blanket or fission gas reservoir located above the core. During operation of the reactor an ultrsonic wave of frequency 10/sup 3/ - 10/sup 4/ Hz is constantly transmitted to the core to resonantly inject the primary bubble with ultrasonic energy to thereby facilitate its growth. Hence, small bubbles grow gradually to prevent the sudden boiling of sodium if an accident occurs in the cooling system during operation of the reactor.

  14. Identification of the neutron-rich nuclides /sup 147; 148/Ba and half- life determination of the heavy isotopes of Rb, Sr, Y, Cs, Ba and La

    CERN Document Server

    Amiel, S; Nir-El, Y; Shmid, M

    1976-01-01

    The neutron nuclides /sup 147; 148/Ba were produced in the thermal neutron induced fission of /sup 235/U. A new surface ionization integrated target ion source operating at temperatures in the region of 1800 degrees C permits the measurement of half-lives of isotopes down to about 0.1 sec due to the very fast release of atoms from the target. Isotopes of Rb, Sr, Cs, and Ba were separated by positive surface ionization and their half-lives measured using beta activity detected by a silicon surface barrier detector with a depletion depth of 300 mu . The isotopes /sup 147/Ba and /sup 148/Ba were identified for the first time and their half-lives were found to be 0.72+or-0.07 sec and 0.47+or-0.20 sec, respectively. (0 refs).

  15. Many-particle and many-hole states in neutron-rich Ne isotopes related to broken N=20 shell closure

    International Nuclear Information System (INIS)

    Kimura, Masaaki; Horiuchi, Hisashi

    2004-01-01

    The low-lying level structures of 26 Ne, 28 Ne and 30 Ne which are related to the breaking of the N=20 shell closure have been studied in the framework of the deformed-basis anti-symmetrized molecular dynamics plus generator coordinate method using the Gogny D1S force. The properties of the many-particle and many-hole states are studied as well as that of the ground band. We predict that the negative-parity states, in which neutrons are promoted into the pf-orbit from the sd orbit, have a small excitation energy in the cases of 28 Ne and 30 Ne. We regard this to be a typical phenomena accompanying the breaking of the N=20 shell closure. It is also found that the neutron 4p4h structure of 30 Ne appears at low excitation energy, which contains α + 16 O correlations. (author)

  16. 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)

  17. Therapeutic efficacy of boron neutron capture therapy mediated by boron-rich liposomes for oral cancer in the hamster cheek pouch model

    Energy Technology Data Exchange (ETDEWEB)

    Heber, Elisa M. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Hawthorne, M. Frederick [Univ. of Missouri, Columbia, MO (United States). International Inst. of Nano and Molecular Medicine; Kueffer, Peter J. [Univ. of Missouri, Columbia, MO (United States). International Inst. of Nano and Molecular Medicine; Garabalino, Marcela A. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Thorp, Silvia I. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Pozzi, Emiliano C. C. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Hughes, Andrea Monti [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Maitz, Charles A. [Univ. of Missouri, Columbia, MO (United States). International Inst. of Nano and Molecular Medicine; Jalisatgi, Satish S. [Univ. of Missouri, Columbia, MO (United States). International Inst. of Nano and Molecular Medicine; Nigg, David W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Curotto, Paula [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Trivillin, Verónica A. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Schwint, Amanda E. [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina)

    2014-11-11

    Unilamellar liposomes formulated with an equimolar mixture of cholesterol and 1,2-distearoyl-sn-glycero-3-phosphocholine, incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the lipid bilayer, and encapsulating Na3[1-(2’-B10-H9)-2-NH3B10H8] were prepared by probe sonication and investigated in vivo. Microwave assisted digestion followed by inductively coupled plasma-optical emission spectroscopy was utilized to determine the biodistribution of boron in various tissues following either a single tail vein injection or two identical injections (separated by 24 hours) of the liposomal suspension in BALB/c mice bearing EMT6 mammary adenocarcinomas in their right flank. Double-injection protocols resulted in a boron content in the tumor exceeding 50 µg of boron per gram of tissue for 48 to 72 hours subsequent to the initial injection while tumor:blood boron ratios were more ideal from 54 hours (1.9:1) to 96 hours (5.7:1) subsequent to the initial injection. Tumor bearing mice were given a double-injection of liposomes containing the 10B-enriched analogs of the aforementioned agents and subjected to a 30 minute irradiation by thermal neutrons with a flux of 8.8 x 108 (±7%) neutrons/cm2 s integrated over the energy range of 0.0 – 0.414 eV. Significant tumor response for a single BNCT treatment was demonstrated by growth curves versus a control group. Vastly diminished tumor growth was witnessed at 14 days (186% increase versus 1551% in controls) in mice that were given a second injection/radiation treatment 7 days after the first. Mice given a one hour neutron irradiation following the double-injection of liposomes had a similar response (169% increase at 14 days) suggesting that neutron fluence is the limiting factor towards BNCT efficacy in this study.

  18. Effects of 2p-2h configurations on low-energy dipole states in neutron-rich N=80, 82 and 84 isotones

    Directory of Open Access Journals (Sweden)

    Arsenyev N. N.

    2016-01-01

    Full Text Available Starting from the Skyrme interaction SLy4 we study the effects of phonon-phonon coupling on the low-energy electric dipole response in 130−134Sn, 132−136Te and 134−138Xe. Our calculations are performed within the finite-rank separable approximation, which enables one to perform quasiparticle random phase approximation calculations in very large two-quasiparticle configuration spaces. A dependence of the pygmy dipole resonance strengths on the neutron skin thickness is found. The inclusion of the two-phonon configurations gives a considerable contribution to the low-lying strength.

  19. 94 β-Decay Half-Lives of Neutron-Rich _{55}Cs to _{67}Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation.

    Science.gov (United States)

    Wu, J; Nishimura, S; Lorusso, G; Möller, P; Ideguchi, E; Regan, P-H; Simpson, G S; Söderström, P-A; Walker, P M; Watanabe, H; Xu, Z Y; Baba, H; Browne, F; Daido, R; Doornenbal, P; Fang, Y F; Gey, G; Isobe, T; Lee, P S; Liu, J J; Li, Z; Korkulu, Z; Patel, Z; Phong, V; Rice, S; Sakurai, H; Sinclair, L; Sumikama, T; Tanaka, M; Yagi, A; Ye, Y L; Yokoyama, R; Zhang, G X; Alharbi, T; Aoi, N; Bello Garrote, F L; Benzoni, G; Bruce, A M; Carroll, R J; Chae, K Y; Dombradi, Z; Estrade, A; Gottardo, A; Griffin, C J; Kanaoka, H; Kojouharov, I; Kondev, F G; Kubono, S; Kurz, N; Kuti, I; Lalkovski, S; Lane, G J; Lee, E J; Lokotko, T; Lotay, G; Moon, C-B; Nishibata, H; Nishizuka, I; Nita, C R; Odahara, A; Podolyák, Zs; Roberts, O J; Schaffner, H; Shand, C; Taprogge, J; Terashima, S; Vajta, Z; Yoshida, S

    2017-02-17

    The β-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of β-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

  20. Total-body sodium and sodium excess

    International Nuclear Information System (INIS)

    Aloia, J.F.; Cohn, S.H.; Abesamis, C.; Babu, T.; Zanzi, I.; Ellis, K.

    1980-01-01

    Total-body levels of sodium (TBNa), chlorine (TBCI), calcium (TBCa), and potassium (TBK) were measured by neutron activation and analysis of results by whole body counting in 66 postmenopausal women. The relationship between TBNa, and TBCl, TBK, and TBCa on the one hand, and height and weight on the other, were found to compare with those previously reported. The hypothesis that TBNa and TBCl are distributed normally could not be rejected. The sodium excess (Na/sub es/) is defined as the sodium that is present in excess of that associated with the extracellular fluid (chlorine) space; the Na/sub es/ approximates nonexchangeable bone sodium. In these 66 postmenopausal women, and in patients with different endocrinopathies previously described, the values on Na/sub es/ did not differ from the normal values except in the thyrotoxicosis patients, where they were decreased. A close relationship between Na/sub es/ and TBCa was maintained in the endocrinopathies studied. This relationship was found in conditions accompanied by either an increment or a loss of skeletal mass. It appears that the NA/sub es/ value is primarily dependent upon the calcium content of bone

  1. 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.

  2. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  3. Cavitation erosion in sodium flow, sodium cavitation tunnel testing

    International Nuclear Information System (INIS)

    Courbiere, Pierre.

    1981-04-01

    The high-volume sodium flows present in fast neutron reactors are liable to induce cavitation phenomena in various portion of the sodium lines and pumps. The absence of sufficient data in this area led the C.E.A. to undertake an erosion research program in cavitating sodium flow. This paper discusses the considerations leading to the definition and execution of sodium cavitation erosion tests, and reviews the tests run with 400 0 C sodium on various steel grades: 316, 316 L, 316 Ti (Z8CNDT17-12), Poral (Z3CND18-12), 304 L and LN2 - clad 316 L (Ni coating-clad 316 L). Acoustic detection and signal processing methods were used with an instrument package designed and implemented at the Cadarache Nuclear Research Center

  4. 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.

  5. Penning-trap mass spectrometry of neutron-rich copper isotopes for probing the Z = 28 and N = 50 shell closures

    CERN Multimedia

    Manea, V

    We propose to perform a Penning-trap mass measurement of $^{79}$Cu. This exotic N = 50 isotone is the last frontier before the doubly-magic $^{78}$Ni and will greatly improve our knowledge of shell evolution. In the same run, we propose $^{77-78}$Cu mass measurements, as well as the search for a possible isomer in $^{76m}$Cu. The data will help to clarify the structure of the odd proton in the Cu isotopes, the influence on the Z = 28 proton core of the νg$_{9/2}$ orbital filling and the impact of the proton-neutron residual interaction on the strength of the N = 50 shell closure.

  6. Study of the nuclear structure far from stability: Coulomb excitation of neutron-rich Rb isotopes around N=60; Production of nuclear spin polarized beams using the tilted foils technique

    International Nuclear Information System (INIS)

    Sotty, C.

    2013-01-01

    The underlying structure in the region A ∼ 100, N ∼ 60 has been under intensive and extensive investigation, mainly by β-decay and γ-ray spectroscopy from fission processes. Around N ∼ 60, by adding just few neutrons, protons a rapid shape change occurs from spherical-like to well deformed g.s. shape. Shape coexistence has been observed in the Sr and Zr nuclei, and is expected to take place in the whole region. The mechanisms involved in the appearance of the deformation is not well understood. The interplay between down-sloping and up-sloping neutron Nilsson orbital is evoked as one of the main reasons for the sudden shape change. However, a clear identification of the active proton and neutron orbitals was still on-going. For that purpose, the neutron rich 93;95;97;99 Rb isotopes have been studied by Coulomb excitation at CERN (ISOLDE) using the REX-ISOLDE post-accelerator and the MINIBALL setup. The completely unknown structures of 97;99 Rb have been populated and observed. Prompt γ-ray coincidences of low-lying states have been observed and time-correlated in order to build level schemes. The associated transition strengths have been extracted with the GOSIA code. The observed matrix elements of the electromagnetic operator constituted new inputs of further theoretical calculations giving new insight on the involved orbitals. The sensitivity of such experiment can be increased using nuclear spin polarized radioactive ion beam. For that purpose the Tilted Foils Technique (TFT) of polarization has been investigated at CERN. This technique consists to spin polarize the ion beam, passing through thin foils tilted at an oblique angle with respect to the beam direction. The initially obtained atomic polarization is transferred to the nucleus by hyperfine interaction. This technique does not depend on the chemical nature of the element. Short lived nuclei can be polarized in-flight without any need to be stopped in a catcher. It opens up the possibility to

  7. Development of an on-line high-temperature ion source for neutron-rich fission products at TRIGA-SPEC

    Energy Technology Data Exchange (ETDEWEB)

    Renisch, Dennis [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz (Germany); Collaboration: TRIGA-SPEC-Collaboration

    2012-07-01

    The TRIGA-SPEC experiment at the TRIGA Mainz research reactor aims to determine ground-state properties of exotic nuclides. It includes the Penning-trap mass spectrometer TRIGA-TRAP and the collinear laser spectroscopy setup TRIGA-LASER. Nuclides of interest are produced in the neutron-induced fission of suitable actinide isotopes, thermalized in a gas-filled volume and transported to an on-line ion source with a gas-jet. The ion source being constructed has two operation modes: a high-temperature surface ionization mode and a hollow cathode plasma mode. It is expected that the surface mode will yield a high ionization efficiency for certain elements, in the order of at least several percent, whereas the plasma mode has the advantage, that more elements can be ionized but with lower efficiency compared to the surface ionization mode. The current status of the TRIGA-SPEC experiments and the present performance of the on-line ion source are presented.

  8. Ground state properties of neutron-rich Mg isotopes the "island of inversion" studied with laser and $\\beta$-NMR spectroscopy

    CERN Document Server

    Kowalska, M

    2006-01-01

    Studies in regions of the nuclear chart in which the model predictions of properties of nuclei fail can bring a better understanding of the strong interaction in the nuclear medium. To such regions belongs the so called "island of inversion" centered around Ne, Na and Mg isotopes with 20 neutrons in which unexpected ground-state spins, large deformations and dense low-energy spectra appear. This is a strong argument that the magic N=20 is not a closed shell in this area. In this thesis investigations of isotope shifts of stable $^{24-26}$Mg, as well as spins and magnetic moments of short-lived $^{29,31}$Mg are presented. The successful studies were performed at the ISOLDE facility at CERN using collinear laser and $\\beta$-NMR spectroscopy techniques. The isotopes were investigated as single-charged ions in the 280 nm transition from the atomic ground state $^2\\!$S$_{1/2}$ to one of the two lowest excited states $^2\\!$P$_{1/2 ,\\,3/2}$ using continuous wave laser beams. The isotope-shift measurements with fluor...

  9. Mass measurements of neutron-rich strontium and rubidium isotopes in the region $A \\approx 100$ and development of an electrospray ionization ion source

    CERN Document Server

    de Roubin, Antoine

    An extension of the atomic mass surface in the region $A \\approx 100$ is performed via mass measurements of the $^{100−102}$Sr and $^{100−102}$Rb isotopes with the ion-trap mass spectrometer ISOLTRAP at CERN-ISOLDE. The first direct mass measurements of $^{102}$Sr and $^{101,102}$Rb are reported here. These measurements confirm the continuation of the region of nuclear deformation with the increase of neutron number, at least as far as $N = 65$. In order to interpret the deformation in the strontium isotopic chain and to determine whether an onset of deformation is present in heavier krypton isotopes, a comparison is made between experimental values and theoretical calculations available in the literature. To complete this comparison, Hartree-Fock-Bogoliubov calculations for even and odd isotopes are also presented, illustrating the competition of nuclear shapes in the region. The development of an electrospray ionization ion source is presented. This source can deliver a large range of isobaric masses ...

  10. Investigating the nuclear structure of the neutron-rich odd-mass Fe isotopes, in the $\\beta$-decay of their parent - Mn

    CERN Document Server

    AUTHOR|(CDS)2079133; Van Duppen, Piet

    For many years the shell structure of the nucleus, originally proposed by Mayer and Haxel, predicting certain energy gaps at specific proton and/or neutron numbers, has been consistent with the experimental findings at or near the line of stability. These nuclei exhibit a sequence of magic numbers – 2, 8, 20, 28, 50, 82, which is different from the one calculated using only a Harmonic Oscillator potential: 2, 8, 20, 40, 70... The strong spin-orbit term, added to the latter potential by Mayer and Haxel, is a necessary requirement for a successful description of these quantum systems, which lowers the energy orbitals with higher spins directly affecting the l = 4 (1$g_{9/2}$) orbit by reducing the gap at N = 40 and creating the N = 50 one. With the development of more exotic radioactive beams, however, it has been observed that for nuclei away from the stability line the traditional shell gaps have weakened, while new energy gaps have emerged instead. It has been further realized that the residual nucleon- nu...

  11. Study of sodium boiling during a power transient in a heating duct. Investigation carried out within the scope of a study on the safety of fast neutron reactors

    International Nuclear Information System (INIS)

    Seiler, J.-M.

    1977-01-01

    This work comprises an experimental study and a physical and theoretical interpretation of sodium boiling during a power transient in conditions simulating a power excursion accident in a breeder reactor. The experimental study was performed on an 'out of pile' system with forced sodium convection. It enabled a detailed study to be made of the draining of the heating duct representing a part of a reactor assembly (expansion of the double-phase area on the heating part of the pin). The physical and theoretical interpretation rests on a very simple calculation model solely describing the heat transfers in the duct, assuming that the fluid stays liquid. The extension of the boiling is governed by the initial overheating and the boiling conditioned by thermal inertias of the walls. The extent of the overheating appears to depend on the degree of initial under-saturation. In the absence of overheating, the rate at which the double-phase front moves is controlled by the saturated boiling. This front is well localised when the central temperature gradient is significant. The draining rate is then directly proportional to the growth rate of the temperature in the liquid. The model employed in the CASPAR code for describing power excursion experiments in single liquid phase is described. This code makes it possible to calculate the heat transfers occurring in a forced system by a heating part, a coolant in movement and possibly a part representing an outer cover [fr

  12. Low sodium diet (image)

    Science.gov (United States)

    ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, ...

  13. High-spin structure of the neutron-rich sup 1 sup 0 sup 9 sup , sup 1 sup 1 sup 1 sup , sup 1 sup 1 sup 3 sup sub 4 sup sub 5 Rh isotopes

    CERN Document Server

    Venkova, T; Bauchet, A; Deloncle, I; Astier, A; Buforn, N; Meyer, M; Prevost, A; Redon, N; Stezowski, O; Lalkovski, S; Donadille, L; Dorvaux, O; Gall, B J P; Schulz, N; Lucas, R; Minkova, A

    2002-01-01

    The sup 1 sup 0 sup 9 sup , sup 1 sup 1 sup 1 sup , sup 1 sup 1 sup 3 Rh nuclei have been produced as fission fragments in the fusion reaction sup 1 sup 8 O + sup 2 sup 0 sup 8 Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of the neutron-rich sup 1 sup 1 sup 1 sup , sup 1 sup 1 sup 3 Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the pi g sub 9 sub / sub 2 , pi p sub 1 sub / sub 2 and pi(g sub 7 sub / sub 2 /d sub 5 sub / sub 2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in sup 1 sup 0 sup 9 sup , sup 1 sup 1 sup 1 Rh, which can be interpreted in terms of three-quasiparticle excitation, pi g sub 9 sub / sub 2 nu h sub 1 sub 1 sub / sub 2 nu g sub 7 sub / sub 2 /d sub 5 sub / sub 2. In addition another structure built on states located at low excitation energy (608 keV in sup 1 sup 1 sup 1 Rh, 570 keV in ...

  14. 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.)

  15. Hidden Sodium

    Centers for Disease Control (CDC) Podcasts

    2013-03-04

    In this podcast, learn about reducing sodium intake by knowing what to eat and the main sources of sodium in the diet. It's important for a healthy lifestyle.  Created: 3/4/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/4/2013.

  16. Dietary sodium

    DEFF Research Database (Denmark)

    Graudal, Niels

    2015-01-01

    The 2013 Institute of Medicine (IOM) report "Sodium Intake in Populations: Assessment of Evidence" did not support the current recommendations of the IOM and the American Heart Association (AHA) to reduce daily dietary sodium intake to below 2,300 mg. The report concluded that the population...

  17. Estimation of the sub-criticality of the sodium-cooled fast reactor Monju using the modified neutron source multiplication method

    International Nuclear Information System (INIS)

    Truchet, G.; Van Rooijen, W. F. G.; Shimazu, Y.; Yamaguchi, K.

    2012-01-01

    The Modified Neutron Source Method (MNSM) is applied to the Monju reactor. This static method to estimate sub-criticality has already given good results on commercial Pressurized Water Reactors. The MNSM consists both in the extraction of the fundamental mode seen by a detector to avoid the effect of higher modes near sources, and the correction of flux distortion effects due to control rod movement. Among Monju's particularities that have a big influence on MNSM factors are: the presence of two californium sources and the position of the detector which is located far from the core outside of the reactor vessel. The importance of spontaneous fission and (α, n) reactions which have increased during the shutdown period of 15 years will also be discussed. The relative position of detectors and sources deeply affect the correction factors in some regions. In order to evaluate the detector count rate, an analytical propagation has been conducted from the reactor vessel. For two subcritical states, an estimation of the reactivity has been made and compared to experimental data obtained in the restart experiments at Monju (2010). (authors)

  18. 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

  19. A method for the manufacture of nuclear-purity sodium

    International Nuclear Information System (INIS)

    Besson, Paul; Graff, Willy.

    1973-01-01

    Description is given of a method for the manufacture of sodium from the amalgam provided by sodium chloride aqueous electrolysis cells, comprising the steps of treating the sodium amalgam by a sodium polysulfide or a mixture of sodium polysulfide in anhydrous alcohol solution, then causing the thus obtained sodium monosulfide to react with a polysulfide or a mixture of polysulfides so as to obtain a mixture of sodium polysulfides with a higher sodium content, and finally separating sodium through the electrolysis of the sodium-rich polysulfides, the electrolysis being carried out in an electrolytic cell with β-alumina solid electrolyte operating at a temperature between 250 and 300 deg C, in which the polysulfide forms the anode compartment and sodium the cathode compartment [fr

  20. Sodium Oxybate

    Science.gov (United States)

    ... or give your sodium oxybate to anyone else; selling or sharing it is against the law. Store ... dehydrogenase deficiency (an inherited condition in which certain substances build up in the body and cause retardation ...

  1. Sodium Azide

    Science.gov (United States)

    ... Exposure to a large amount of sodium azide by any route may cause these other health effects as well: Convulsions Low blood pressure Loss of consciousness Lung injury Respiratory failure leading to death Slow heart rate ...

  2. Microcantilever-Enabled Neutron Detection

    Directory of Open Access Journals (Sweden)

    Kevin R. Kyle

    2014-04-01

    Full Text Available A new concept for neutron radiation detection was demonstrated using piezoresistive microcantilevers as the active sensing element. Microcantilevers were used to measure the tiny volumetric changes in a sensing material upon absorption of neutron radiation and transmutation into a new element. Highly ordered inorganic crystalline lattices of boron-rich materials dispersed in polymeric rubber matrices were shown to act as volumetric neutron transducers.

  3. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  4. Sodium purification in Rapsodie; La purification du sodium a Rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Giraud, B [Commissariat a l' Energie Atomique, Dir. des Piles Atomiques, Cadarache (France). Centre d' Etudes Nucleaires

    1968-07-01

    This report is one of a series of publications presenting the main results of tests carried out during the start-up of the first french fast neutron reactor: Rapsodie. The article presents the sodium purification techniques used in the reactor cooling circuits both from the constructional point of view and with respect to results obtained during the first years working. (author) [French] Ce rapport fait partie d'une serie de publications presentant l'essentiel des resultats des essais effectues a l'occasion du demarrage du premier reacteur francais a neutrons rapides: RAPSODIE. Cet article expose les techniques de la purification du sodium utilise dans les circuits de refroidissement du reacteur tant au point de vue de leur realisation technologique, que des resultats obtenus pendant la premiere annee de fonctionnement. (auteur)

  5. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  6. 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.

  7. Assessing rare earth elements in quartz rich geological samples

    International Nuclear Information System (INIS)

    Santoro, A.; Thoss, V.; Ribeiro Guevara, S.; Urgast, D.; Raab, A.; Mastrolitti, S.; Feldmann, J.

    2016-01-01

    Sodium peroxide (Na_2O_2) fusion coupled to Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS) measurements was used to rapidly screen quartz-rich geological samples for rare earth element (REE) content. The method accuracy was checked with a geological reference material and Instrumental Neutron Activation Analysis (INAA) measurements. The used mass-mode combinations presented accurate results (only exception being "1"5"7Gd in He gas mode) with recovery of the geological reference material QLO-1 between 80% and 98% (lower values for Lu, Nd and Sm) and in general comparable to INAA measurements. Low limits of detection for all elements were achieved, generally below 10 pg g"−"1, as well as measurement repeatability below 15%. Overall, the Na_2O_2/ICP-MS/MS method proved to be a suitable lab-based method to quickly and accurately screen rock samples originating from quartz-rich geological areas for rare earth element content; particularly useful if checking commercial viability. - Highlights: • Na_2O_2 fusion coupled to ICP-MS/MS was used to determine REE in quartz-rich samples. • The method accuracy was checked with a geological reference material and INAA. • Results were within 80–98% recovery of QLO-1 reference material, comparable to INAA. • Detection limits were generally below 10 pg g"−"1, and repeatability was below 15%. • Na_2O_2/ICP-MS/MS proved to be a suitable method for REE in quartz-rich samples.

  8. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  9. Assessing rare earth elements in quartz rich geological samples.

    Science.gov (United States)

    Santoro, A; Thoss, V; Ribeiro Guevara, S; Urgast, D; Raab, A; Mastrolitti, S; Feldmann, J

    2016-01-01

    Sodium peroxide (Na2O2) fusion coupled to Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS) measurements was used to rapidly screen quartz-rich geological samples for rare earth element (REE) content. The method accuracy was checked with a geological reference material and Instrumental Neutron Activation Analysis (INAA) measurements. The used mass-mode combinations presented accurate results (only exception being (157)Gd in He gas mode) with recovery of the geological reference material QLO-1 between 80% and 98% (lower values for Lu, Nd and Sm) and in general comparable to INAA measurements. Low limits of detection for all elements were achieved, generally below 10 pg g(-1), as well as measurement repeatability below 15%. Overall, the Na2O2/ICP-MS/MS method proved to be a suitable lab-based method to quickly and accurately screen rock samples originating from quartz-rich geological areas for rare earth element content; particularly useful if checking commercial viability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Measurement of Q{sub {beta}} values of neutron-rich Tc to Pd isotopes in the mass range A=110 to A=117; Messung von Q{sub {beta}}-Werten neutronenreicher Tc- bis Pd-Isotope im Massenbereich A=110 bis A=117

    Energy Technology Data Exchange (ETDEWEB)

    Kloeckl, Ingo

    2008-06-15

    The present work describes the measuring of Q{sub {beta}} values of {beta}-instable isotopes of Tc, Ru, Rh and Pd. The mass range A=110 to 117 comprises neutron-rich, short-living isotopes. Due to their small (fission) abundances, few data are known, especially regarding level schemes or gamma radiation. The proton-induced fission and a fast online mass separation was used to produce these nuclides in the IGISOL facility located in Jyvaeskylaein Finland. The {beta},{gamma},X coincidence apparatus used during the experiments allows measuring Q{sub {beta}} values as well as {gamma},X coincidences. The latter represent the basic input data for a calculation of Q{sub {beta}} values out of {beta},{gamma} coincidences. It is so possible to examine nuclides with incomplete level schemes; similarly, these level schemes can be extended using beta,gamma coincidence data. Twelve Q{sub {beta}} values of neutron-rich Tc to Pd isotopes could be determined, yielding nuclear masses, mass defects and neutron separation energies. Eight of them were determined for the first time; another one could be confirmed. For three more, the error of earlier values could be decreased by a factor of nearly ten. The resulting data are of interest for the review of nuclear mass models, they represent also input in astrophysical network calculations. (orig.)

  11. Test Your Sodium Smarts

    Science.gov (United States)

    ... You may be surprised to learn how much sodium is in many foods. Sodium, including sodium chloride ... foods with little or no salt. Test your sodium smarts by answering these 10 questions about which ...

  12. [Present conceptions of the C.E.A. concerning] the development of fast neutron reactors in France; [Les conceptions actuelles du C.E.A. concernant] la filiere des reacteurs a neutrons rapides en France

    Energy Technology Data Exchange (ETDEWEB)

    Vendryes, G; Gaussens, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Pasquer, R [Electricite de France (EDF), 75 - Paris (France)

    1964-07-01

    1 - The position of fast neutron reactors in the French nuclear energy program. In developing a program based on natural uranium, France will have an important stock of plutonium rich in higher isotopes. The existence of this plutonium and of the depleted uranium arising from the same reactors, has, as a logical consequence, the use of both in fast neutron reactors. Justified by this short term interest, the achievement of fast neutron reactors does, moreover, provide for a future necessity. 2 - Description of a fast neutron central power station of 1000 MWe. We indicate the characteristics of a future fast neutron central power station, plutonium fuelled, and sodium cooled. However uncertain these characteristics may be, they constitute a necessary guide in the orientation of our work. 3 - Studies carried out up to the present time. We give an outline of those studies, often very preliminary, which have given the characteristics cited above. The principal technical areas taken up are the following: - Neutronics (critical masses, breeding ratios, enrichments, flattening of the neutron flux, coefficients of reactivity, reactivity changes as a function of irradiation). - Dynamics, control, and safety. - Technology (design of the core and vessel, of the sodium system, and of the fuel handling mechanisms). These technical studies are complemented by economic considerations. The choice of the optimum characteristics is related to the existence of power production programs, and, in these programs, to the existence of plutonium producing thermal reactors. It is shown how, in this context, the existence of plutonium should be taken into account, and, in addition which mechanisms relate the economics of this plutonium to the choice of the most important parameters of the breeder reactors. 4 - Prototype reactor. The interest in an intermediate stage consisting of a reactor of a power level of about 80 MWe is justified. Its essential characteristics are briefly presented

  13. [Present conceptions of the C.E.A. concerning] the development of fast neutron reactors in France

    International Nuclear Information System (INIS)

    Vendryes, G.; Gaussens, J.

    1964-01-01

    1 - The position of fast neutron reactors in the French nuclear energy program. In developing a program based on natural uranium, France will have an important stock of plutonium rich in higher isotopes. The existence of this plutonium and of the depleted uranium arising from the same reactors, has, as a logical consequence, the use of both in fast neutron reactors. Justified by this short term interest, the achievement of fast neutron reactors does, moreover, provide for a future necessity. 2 - Description of a fast neutron central power station of 1000 MWe. We indicate the characteristics of a future fast neutron central power station, plutonium fuelled, and sodium cooled. However uncertain these characteristics may be, they constitute a necessary guide in the orientation of our work. 3 - Studies carried out up to the present time. We give an outline of those studies, often very preliminary, which have given the characteristics cited above. The principal technical areas taken up are the following: - Neutronics (critical masses, breeding ratios, enrichments, flattening of the neutron flux, coefficients of reactivity, reactivity changes as a function of irradiation). - Dynamics, control, and safety. - Technology (design of the core and vessel, of the sodium system, and of the fuel handling mechanisms). These technical studies are complemented by economic considerations. The choice of the optimum characteristics is related to the existence of power production programs, and, in these programs, to the existence of plutonium producing thermal reactors. It is shown how, in this context, the existence of plutonium should be taken into account, and, in addition which mechanisms relate the economics of this plutonium to the choice of the most important parameters of the breeder reactors. 4 - Prototype reactor. The interest in an intermediate stage consisting of a reactor of a power level of about 80 MWe is justified. Its essential characteristics are briefly presented

  14. Effectiveness of Chlorinated Water, Sodium Hypochlorite, Sodium ...

    African Journals Online (AJOL)

    This study evaluated the efficacy of chlorinated water, sodium hypochlorite solution, sodium chloride solution and sterile distilled water in eliminating pathogenic bacteria on the surfaces of raw vegetables. Lettuce vegetables were dipped in different concentrations of chlorinated water, sodium hypochlorite solution, sodium ...

  15. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  16. Analysis of a small Fast Sodium Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Gilberti, Mauricio, E-mail: mgilber@eletronuclear.gov.br [Eletrobrás Termonuclear S.A. (ELETRONUCLEAR), Rio de Janeiro, RJ (Brazil); Velasquez, Carlos E.; Vargas, Matheus L.; Martins, Felipe; Costa, Antonella L.; Veloso, Maria Auxiliadora F.; Pereira, Claubia, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    This paper presents the analyses and initial results of a Small Fast Sodium Reactor (SFSR) simulated using MCNPX. The goal is to build a nuclear model and determine the main core neutronic parameters over the cycle. Neutronics parameters such as burnup neutronic behavior, depletion fuel composition, absorbing elements, core reactivity control and reactivity coefficients that affect the reactor cooled by sodium along its operation cycle have been analyzed. The parameters are evaluated in terms of the reactivity coefficients at different cycle stages. The results present a comparison and discussion of the differences found between the model developed and some information available in the literature for a similar project. (author)

  17. Adiabatic flame temperature of sodium combustion and sodium-water reaction

    International Nuclear Information System (INIS)

    Okano, Y.; Yamaguchi, A.

    2001-01-01

    In this paper, background information of sodium fire and sodium-water reaction accidents of LMFBR (liquid metal fast breeder reactor) is mentioned at first. Next, numerical analysis method of GENESYS is described in detail. Next, adiabatic flame temperature and composition of sodium combustion are analyzed, and affect of reactant composition, such oxygen and moisture, is discussed. Finally, adiabatic reaction zone temperature and composition of sodium-water reaction are calculated, and affects of reactant composition, sodium vaporization, and pressure are stated. Chemical equilibrium calculation program for generic chemical system (GENESYS) is developed in this study for the research on adiabatic flame temperature of sodium combustion and adiabatic reaction zone temperature of sodium-water reaction. The maximum flame temperature of the sodium combustion is 1,950 K at the standard atmospheric condition, and is not affected by the existence of moisture. The main reaction product is Na 2 O (l) , and in combustion in moist air, with NaOH (g) . The maximum reaction zone temperature of the sodium-water reaction is 1,600 K, and increases with the system pressure. The main products are NaOH (g) , NaOH (l) and H2 (g) . Sodium evaporation should be considered in the cases of sodium-rich and high pressure above 10 bar

  18. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  19. Quantum physics with neutrons

    International Nuclear Information System (INIS)

    Durstberger, K.; Hasegawa, Y.; Klepp, J.; Sulyok, G.; Rauch, H.

    2008-01-01

    Full text: Fundamental quantum properties like quantum coherence and entanglement are among the most interesting features of quantum mechanics. The physical system of interest is the (massive) neutron subjected to interferometric and polarimetric measurements. Neutrons are proper objects for a study of quantum mechanical behavior: they allow for rather easy experimental control and the neutron spin is the simplest two-level system with easy manipulation by magnetic fields. In combination with interferometric measurements the system has enough intrinsic richness to show interesting quantum features such as entanglement. The coupling of the neutron to an external magnetic field allows for selective manipulations of the spinor quantum states. This can be used, on the one hand, to create entangled states where the entanglement occurs between different degrees of freedom (e.g. spin and path) and, on the other hand, one can introduce dephasing and decoherence by varying magnetic fields. We investigate different kinds of entanglement for the neutron system and mechanisms for decoherence and dephasing. We discuss weak measurements and their realization for neutrons where information about the system can be revealed without disturbing the system too much. Beyond the theoretical work we develop experimental strategies to check the results directly in suitably designed experiments. The experimental work is done at the Institute Laue-Langvine (ILL) in Grenoble, France. (author)

  20. Sodium ordering and the control of magnetism in sodium cobaltate

    International Nuclear Information System (INIS)

    Morris, D.J.P.; Roger, M.; Tennant, D.A.; Goff, J.P.; Gutmann, M.J.; Hoffmann, J.-U.; Prabhakaran, D.; Shannon, N.; Lake, B.; Deen, P.P.

    2007-01-01

    The long-range three-dimensional ordering of Na + ions was studied in a sample of composition Na 0.75 CoO 2 using single-crystal neutron diffraction. Large-scale numerical simulations reveal the ordering principle for this system, the formation of multi-vacancy charged droplets then order long range, and the structure factors from these defect clusters are in good agreement with the observed neutron diffraction intensities. The electrostatic potential is found to be the dominant factor in determining the sodium ordering and its associated distortion field. The superstructures induce a periodic potential in the CoO 2 , giving potential wells that are larger than the single-particle hopping frequency and so able to localize holes. The results readily explain many of the observed electrical and magnetic properties, including the three dimensionality of the magnetic excitations

  1. Sodium in diet

    Science.gov (United States)

    Diet - sodium (salt); Hyponatremia - sodium in diet; Hypernatremia - sodium in diet; Heart failure - sodium in diet ... Too much sodium in the diet may lead to: High blood pressure in some people A serious buildup of fluid in people with heart failure , cirrhosis of ...

  2. Evolution of the pi g sub 9 sub / sub 2 x nu h sub 1 sub 1 sub / sub 2 configuration in the neutron-rich sup 1 sup 1 sup 0 sup , sup 1 sup 1 sup 2 sub 4 sub 5 Rh and sup 1 sup 1 sup 4 sup , sup 1 sup 1 sup 6 sub 4 sub 7 Ag isotopes

    CERN Document Server

    Porquet, M G; Deloncle, I; Venkova, T; Astier, A; Buforn, N; Meyer, M; Prevost, A; Redon, N; Stezowski, O; Donadille, L; Dorvaux, O; Gall, B J P; Schulz, N; Lalkovski, S; Lucas, R; Minkova, A

    2003-01-01

    The sup 1 sup 1 sup 0 sup , sup 1 sup 1 sup 2 Rh and sup 1 sup 1 sup 4 sup , sup 1 sup 1 sup 6 Ag nuclei have been produced as fission fragments in the fusion reaction sup 1 sup 8 O+ sup 2 sup 0 sup 8 Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of these neutron-rich nuclei have been identified for the first time. The yrast structures consist of rotational bands in which the odd proton occupies the pi g sub 9 sub / sub 2 sub-shell and the odd neutron the nu h sub 1 sub 1 sub / sub 2 sub-shell. The evolution of the pi g sub 9 sub / sub 2 x nu h sub 1 sub 1 sub / sub 2 band structure is analyzed as a function of the neutron number.

  3. Modeling delayed neutron monitoring systems for fast breeder reactors

    International Nuclear Information System (INIS)

    Bunch, W.L.; Tang, E.L.

    1983-10-01

    The purpose of the present work was to develop a general expression relating the count rate of a delayed neutron monitoring system to the introduction rate of fission fragments into the sodium coolant of a fast breeder reactor. Most fast breeder reactors include a system for detecting the presence of breached fuel that permits contact between the sodium coolant and the mixed oxide fuel. These systems monitor for the presence of fission fragments in the sodium that emit delayed neutrons. For operational reasons, the goal is to relate the count rate of the delayed neutron monitor to the condition of the breach in order that appropriate action might be taken

  4. Neutron physics entering the 21st century

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    2000-01-01

    The objectives of present-day neutron physics are neutron-aided investigations of fundamental interactions and symmetries, high excited states of nuclei, crystalline and magnetic structures, dynamic excitations in solids and liquids over a wide range of energies. The state-of-art and perspectives of the solution of most topical and principle problems of neutron physics are analyzed. The main conclusion is that neutron physics provides rich information for nuclear particle physics, physics of nucleus, condensed matter physics, chemistry, biology, materials science, and earth sciences. In the next century, however, new higher flux neutron sources must be created. By the year 2010 the number of nuclear reactors used for physical research will reduce to 10-15 reactors over the world. Trends in the development of neutron sources are analyzed. The possibilities of leading neutron research centers in the world are considered and most promising projects of neutron sources are discussed. (author)

  5. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  6. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  7. First delayed neutron emission measurements at ALTO with the neutron detector TETRA

    International Nuclear Information System (INIS)

    Testov, D.; Ancelin, S.; Bettane, J.; Ibrahim, F.; Kolos, K.; Mavilla, G.; Niikura, M.; Verney, D.; Wilson, J.; Kuznetsova, E.; Penionzhkevich, Yu.; Smirnov, V.; Sokol, E.

    2013-01-01

    Beta-decay properties are among the easiest and, therefore, the first ones to be measured to study new neutron-rich isotopes. Eventually, a very small number of nuclei could be sufficient to estimate their lifetime and neutron emission probability. With the new radioactive beam facilities which have been commissioned recently (or will be constructed shortly) new areas of neutron-rich isotopes will become reachable. To study beta-decay properties of such nuclei at IPN (Orsay) in the framework of collaboration with JINR (Dubna), a new experimental setup including the neutron detector of high efficiency TETRA was developed and commissioned

  8. Sodium technology handbook

    International Nuclear Information System (INIS)

    2005-09-01

    This document was published as a textbook for the education and training of personnel working for operations and maintenances of sodium facilities including FBR plants and those engaged in R and D activities related to sodium technology. This handbook covers the following technical areas. Properties of sodium. Compatibilities of sodium with materials. Thermalhydraulics and structural integrity. Sodium systems and components. Sodium instrumentations. Sodium handling technology. Sodium related accident evaluation and countermeasures for FBRs. Operation, maintenance and repair technology of sodium facilities. Safety measures related to sodium. Laws, regulations and internal rules related to sodium. The plannings and discussions of the handbook were made in the Sodium Technology Education Committee organized in O-arai Engineering Center consisting of the representatives of the related departments including Tsuruga headquarters. Experts in various departments participated in writing individual technical subjects. (author)

  9. Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Thomas

    2016-10-19

    The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

  10. The NSCL neutron wall facility

    International Nuclear Information System (INIS)

    Zecher, P.; Galonsky, A.; Kruse, J.

    1995-01-01

    The authors have constructed and installed a large-area, high-efficiency neutron detector at the NSCL. The motivation behind the detector's design was provided by their desire to improve a previous experiment, where they measured the soft-dipole-resonance parameters and ground state n-n correlations in 11 Li, and to perform similar experiments on other neutron-rich halo nuclei. The detector consists of two planes of liquid scintillator, each 4 square meters in area; it is position sensitive and is capable of neutron-γ-ray discrimination. A general overview of the detector's design and measurements of its performance in test experiments will be presented

  11. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  12. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  13. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  14. Liquid sodium pool fires

    Energy Technology Data Exchange (ETDEWEB)

    Casselman, C [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

    1979-03-01

    Experimental sodium pool combustion results have led to a definition of the combustion kinetics, and have revealed the hazards of sodium-concrete contact reactions and the possible ignition of organic matter (paint) by hydration of sodium peroxide aerosols. Analysis of these test results shows that the controlling mechanism is sodium evaporation diffusion. (author)

  15. Liquid sodium pool fires

    International Nuclear Information System (INIS)

    Casselman, C.

    1979-01-01

    Experimental sodium pool combustion results have led to a definition of the combustion kinetics, and have revealed the hazards of sodium-concrete contact reactions and the possible ignition of organic matter (paint) by hydration of sodium peroxide aerosols. Analysis of these test results shows that the controlling mechanism is sodium evaporation diffusion. (author)

  16. A large animal model for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Gavin, P.R.; Kraft, S.L.; DeHaan, C.E.; Moore, M.P.; Griebenow, M.L.

    1992-01-01

    An epithermal neutron beam is needed to treat relatively deep seated tumors. The scattering characteristics of neutrons in this energy range dictate that in vivo experiments be conducted in a large animal to prevent unacceptable total body irradiation. The canine species has proven an excellent model to evaluate the various problems of boron neutron capture utilizing an epithermal neutron beam. This paper discusses three major components of the authors study: (1) the pharmacokinetics of borocaptate sodium (NA 2 B 12 H 11 SH or BSH) in dogs with spontaneously occurring brain tumors, (2) the radiation tolerance of normal tissues in the dog using an epithermal beam alone and in combination with borocaptate sodium, and (3) initial treatment of dogs with spontaneously occurring brain tumors utilizing borocaptate sodium and an epithermal neutron beam

  17. In vivo neutron activation at the Sloan-Kettering Institute

    International Nuclear Information System (INIS)

    Bigler, R.E.

    1986-01-01

    A medical cyclotron (Model CS-15, The Cyclotron Corporation, Berkeley, CA) with a multi-layer neutron collimator designed for partial body neutron irradiations and a low-background patient counting facility have been established for measurement of bone calcium and sodium; and soft tissue, exchangeable sodium and chlorine. The cyclotron also provides total-body calcium by the 37 Ar method of Palmer. (author)

  18. Small liquid sodium leaks

    International Nuclear Information System (INIS)

    Dufresne, J.; Rochedereux, Y.; Antonakas, D.; Casselman, C.; Malet, J.C.

    1986-05-01

    Usually, pessimistic considerations inassessing the safety of secondary sodium loops in LMFBR reactor lead to assume guillotine rupture releasing a large amount of sodium estimate the consequences of large sodium fires. In order to reduce these consequences, one has to detect the smallest leak as soon as possible and to evaluate the future of an initial small leak. Analysis of the relationship between crack size and sodium outflow rate; Analysis of a sodium pipe with a small open crack

  19. Dog rose (Rosa canina L.) as a functional ingredient in porcine frankfurters without added sodium ascorbate and sodium nitrite.

    Science.gov (United States)

    Vossen, Els; Utrera, Mariana; De Smet, Stefaan; Morcuende, David; Estévez, Mario

    2012-12-01

    The effect of dog rose (Rosa canina L.; RC), rich in polyphenols and ascorbic acid, on lipid and protein oxidation, colour stability and texture of frankfurters was investigated. Four treatments were prepared: with 5 or 30 g/kg RC extract and without sodium ascorbate and sodium nitrite (5RC and 30RC, respectively), a positive control (with sodium ascorbate and sodium nitrite; PC) and a negative control (without sodium ascorbate, sodium nitrite or RC extract; NC). Hexanal values were much higher throughout storage in NC compared to RC and PC frankfurters (Prose can act as a natural antioxidant in frankfurters, but not as full replacer for sodium nitrite. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)