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Fission measurements have a long history at Los Alamos. This paper reviews the current programs in neutron-induced fission at the Los Alamos Neutron Science Center. [ABSTRACT FROM AUTHOR]

Elemental characterization of low Z elements (C,H,Cl,Fe) inside bulk materials were performed using PGNAA technique. Samples having elemental composition similar to explosives were used for such experimentations using moderated DD neutrons as well as DT(14MeV) neutrons. We could observe characteristic prompt capture gamma rays of hydrogen (2.224MeV), nitrogen (10.83 MeV), chlorine (6.11 MeV) and Fe (6.02MeV and 7.63MeV) also (n,n'γ) prompt gamma signal (4.43MeV) of carbon. BGO detector has been used for gamma spectrum acquisition. These experimentations has been carried out for initial feasibility studies of detecting prompt gamma lines as a part of PGNAA technique based explosive detection system development. A detail description of experimental set up and procedure has been discussed in paper. [ABSTRACT FROM AUTHOR]

In spite of the huge amount of fission yield data available in different libraries, more accurate values are still needed for nuclear energy applications and to improve our understanding of the fission process. Thus measurements of fission yields were performed at the mass spectrometer Lohengrin at the Institut Laue-Langevin in Grenoble, France. The mass separator Lohengrin is situated at the research reactor of the institute and permits the placement of an actinide layer in a high thermal neutron flux. It separates fragments according to their atomic mass, kinetic energy and ionic charge state by the action of magnetic and electric fields. Coupled to a high resolution ionization chamber the experiment was used to investigate the mass and isotopic yields in the light mass region. Almost all fission yields of isotopes from Th to Cf have been measured at Lohengrin with this method. It has been extended in this work to the heavy mass region for the reactions 235U(nth,f), 239Pu(nth,f), and 241Pu(nth,f). For these higher masses an isotopic separation is no longer possible. So, a new method was undertaken with the reaction 239Pu(nth,f) to determine the isotopic yields by γ spectrometry. The results are presented in this paper. [ABSTRACT FROM AUTHOR]

On the base of modified trajectory calculations the shift of angular distribution of α-particles accompanied the reaction 235U(n,f) induced by cold polarized neutrons is evaluated. It was supposed that angular distribution shift is caused by the rotation of nuclear system before scission. The orientation of a rotation motion is determined by the neutron spin polarization along and opposite to the beam direction. For the first time the estimation was done in the frame of trajectory calculations assuming the rotation motion of scissioning nucleus [1]. The result of the calculation is in a good agreement with experimental data of paper [2], where this new phenomenon was named as ROT-effect. [ABSTRACT FROM AUTHOR]

Presented in this paper are some of the latest measurements of photoneutron cross sections of direct relevance to the p-process nucleosynthesis in the context of the statistical model of compound nuclear reactions. We discuss the p-process origin of the rarest nuclide and the only naturally occurring isomer 180Tam, a serious underproduction problem of 138La, and the nuclear level density of 180Ta determined from the partial photoneutron cross section for 180Tam. As the laser-Compton scattering γ ray at AIST has enabled one to directly determine (γ,n) cross sections, the blackbody synchrotron radiation to be produced by a ten-Tesla superconducting wiggler at SPring-8 is expected to be a promising tool for exploring (γ,α) and (γ,p) reactions in the future. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Fast neutrons play crucial roles as a probe to trace the history of the universe. The present paper describes our recent work on the measurement of the neutron capture and neutron inelastic scattering cross sections of various nuclei from primordial and stellar nucleostyntheses point of view, which have been carried out by developing a high sensitive measurement system. The obtained results are compared to previous works and theoretical calculations. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper among the wide-ranging applications of nuclear methods the following topics were selected: a) Nuclear safeguards, illicit trafficking and demining; b) Bulk hydrogen analysis; c) Radiopharmaceuticals and related charged particle reactions; d) Accelerator transmutation of radioactive waste; e) Validation of nuclear data libraries by differential and integral measurements. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Using multiple liquid-scintillatior detectors at distances between 0.1 and 3 km from a nuclear reactor has the potential to determine the yet unknown neutrino-mixing angle θ13 via inverse β-decay reaction on protons. The coincidence tag between the emitted prompt positron and delayed neutron provides a clear signature of anti-neutrino event. The neutron capture signal is greatly enhanced by loading gadolinium into the liquid scintillator, due to the large (n, γ) cross sections of Gd isotopes. BNL has developed a procedure to synthesize Gd-loaded scintillator with long attenuation length (> 10 m), high light output (> 95% of pseudocumene), and long-tern stability (> 5 months to date). The purification and chemical quality of BNL-synthesized Gd-LS are discussed in the paper. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Cosmogenic-induced activity is an issue of great concern for many sensitive experiments sited underground. A variety of different arch-type experiments — such as those geared toward the detection of dark matter, neutrinoless double beta decay and solar neutrinos — have reached levels of cleanliness and sensitivity that warrant careful consideration of secondary activity induced by cosmic rays. This paper reviews some of the main issues associated with the modeling of cosmogenic activity underground. Comparison with data, when such data is available, is also presented. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

High Power Proton Accelerators (HPPAs) are studied for several projects based on high-flux neutron sources driven by proton or deuteron beams. Since the front end is considered as the most critical part of such accelerators, the two French national research agencies CEA and CNRS decided to collaborate in 1997 to study and build a High-Intensity Proton Injector (IPHI). The main objective of this project is to master the complex technologies used and the concepts of manufacturing and controlling the HPPAs. Recently, a collaboration agreement was signed with CERN and led to some evolutions in the design and in the schedule. The IPHI design current was maintained at 100 mA in Continuous Wave mode. This choice should allow to produce a high reliability beam at reduced intensity (typically 30 mA) tending to fulfill the Accelerator Driven System requirements. The output energy of the Radio Frequency Quadrupole (RFQ), was reduced from 5 to 3 MeV, allowing then the adjunction and the test, in pulsed operation of a chopper line developed by CERN for the Superconducting Proton Linac (SPL). In a final step, the IPHI RFQ and the chopper line should become parts of the SPL injector. In this paper, the IPHI project and the recent evolutions are reported together with the construction and operation schedule. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Proton and neutron data as well as photon data are necessary in various intermediate energy applications. To meet these requirements, many groups in the world continue some activities concerning nuclear data evaluation in the energy range above 20 MeV, which is the upper limit of conventional general-purpose evaluated nuclear data files. In this paper, reviewed is brief history of intermediate energy nuclear data development as well as Pearlstein’s contribution for it. Present status of world evaluated nuclear data files in the intermediate energy region is reported as well as evaluation methodology and sample results of evaluation and integral benchmark tests by using the case of JENDL High Energy File as an example. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A new evaluated nuclear data library has been created. The library consists of two sub-libraries for neutron and proton incident particles. The first version of neutron sub-library has been completed and described in the present paper. The library contains nuclear data for transport, heating, and shielding applications for 242 nuclides ranging in atomic number from 8 to 82 in the energy region of primary neutrons from 10-5 eV to 150 MeV. Data below 20 MeV are taken mainly from ENDF/B-VI (Revision 8) and for some nuclides, from the JENDL-3.3 and JEFF-3.0 libraries. The evaluation of emitted particle energy and angular distributions at the energies above 20 MeV was performed with the help of the ALICE/ASH code and the analysis of available experimental data. The total cross sections, elastic cross sections, and elastic scattering angular distributions were calculated with the help of the coupled channel model. The results of the calculation were adjusted to the data from ENDF/B-VI, JENDL-3.3m or JEFF-3.0 at the neutron energy equal to 20 MeV. The library is written in ENDF/B-VI format using the MF=3/MT=5 and MF=6/MT=5 representations. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Rhodium-103 is a prominent fission product in nuclear reactors as well as a usual detector in fast neutron activation or dosimetry techniques. The neutron-induced reactions and the energy regions of interest differ significantly depending on the applications. In this paper, a new evaluation spanning the 0- to 30-MeV energy range is described. The quality of the transitions between the various energy intervals was assessed with the help of statistical techniques to test the resonance parameter distributions and the SPRT method to check optical model calculations. The evaluated nuclear data file was verified and processed. The quality of the data was successfully tested against both differential and integral results for activation, thermal and fast reactor applications. This new file should be part of the upcoming JEFF-3.1 library. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The initial objective of this work was an updated review on the Am isotopes data since the next official release (3.1) of the JEFF3 evaluated data file is foreseen around June 2005. Alternatively, this work searches for the possible reasons of the observed discrepancies between differential and integral measurement results. In particular, strong differences are encountered on σγth values and epithermal branching ratio values for the 241Am. Although the JEF2.2 validation is used as guide in parallel with a systematic study of all differential and integral results available, the need for new measurements clearly shows up. This paper finally draws up a list of desired and feasible new differential and integral measurements on the Am isotopes. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Starting with a discussion of the requirements and goals for high quality general-purpose evaluations the paper will describe the procedures chosen in our evaluation work for JEFF for producing new general evaluations with complete covariance information for all cross sections (file 3 data). Key problems essential for the goal of making the best possible use of the existing theoretical and experimental knowledge on neutron interactions with the respective nuclide will be addressed, especially the problem of assigning covariances to calculated cross sections, necessary checking procedures for all experimental data and various possibilities to amend the experimental database beyond the obvious use of EXFOR data for the respective cross sections. In this respect both, the use of elemental cross sections in isotopic evaluations and the use of implicit cross-section data (that is data which can be converted into cross sections by simple methods) will be discussed in some detail. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Neutron and gamma spectra were measured behind and inside of modules consisting of variable iron and water slabs that were installed in radial beams of the zero-power training and research reactors AKR of the Technical University Dresden and ZLFR of the University of Applied Sciences Zittau/Goerlitz. The applied NE-213 scintillation spectrometer did allow the measurement of gamma and neutron fluence spectra in the energy regions 0.3–10 MeV for photons and 1.0–20 MeV for neutrons. The paper describes the experiments and presents important results of the measurements. They are compared with the results of Monte Carlo transport calculations made by means of the codes MCNP and TRAMO on an absolute scale of fluences. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Experiments with slow neutrons can be used to address a number of scientific issues in the areas of nuclear, particle, and astrophysics, and this conference includes a number of examples. We give in this paper a brief overview of the scientific issues. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The neutron Time of Flight (n_TOF) facility at CERN is a source of a wide-range (1 eV

The Los Alamos Neutron Science Center, or LANSCE, is an accelerator-based national user facility for research in basic and applied science using four experimental areas. LANSCE has two areas that provide neutrons generated by the 800-MeV proton beam striking tungsten target systems. A third area uses the proton beam for radiography. The fourth area uses 100 MeV protons to produce medical radioisotopes. This paper describes the four LANSCE experimental areas, gives nuclear science highlights of the past operating period, and discusses plans for the future. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We show that extreme nuclear halos are caused only by pairs of s-wave neutrons (or single s-wave neutrons) and that such states occur much more frequently in the periodic table than previously believed. Besides lingering long near zero neutron separation energy such extreme halos have very remarkable properties: they can contribute significantly to the nuclear density at more than twice the normal nuclear radius and their spreading width can be very narrow. The properties of these states are primarily determined by the “thickness” of the nuclear surface in the mean-free nuclear potential and thus their importance increases greatly as we approach the neutron drip line. We discuss what such extreme halos are, where they occur, what their properties are and some of their impact on nuclear observations. [ABSTRACT FROM AUTHOR]

The current version of the European Activation File is EAF-2003. This contains various libraries of nuclear data required for activation calculations. An important component is the neutron-induced cross-section library. Plans to expose fusion components to high neutron fluxes include the IFMIF materials testing facility. This accelerator-based device will produce neutrons with a high-energy tail up to about 55 MeV. In order to carry out activation calculations on materials exposed to such neutrons it is necessary to extend the energy range of the cross-section library. Work on extending the energy range to 60 MeV is nearing completion. A test version (EAF-2004) was produced at the end of 2003 showing the feasibility of the chosen approach. This library required calculated data to extend the existing data from 20–60 MeV and to enlarge it with new classes of reactions with high thresholds. A summary of the new library EAF-2005, which is under development and is planned for distribution at the beginning of 2005, is given. The other files in EAF-2005 are briefly described; these cover cross-section uncertainty information and decay data. Both these have been extended beyond the current version to allow activation calculations at energies up to 60 MeV. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The analysis code SAMMY is widely used for parameterization and understanding of neutron- and charged-particle-induced cross-section data. This report describes advances made in the development of the code: An overview of the main features of SAMMY is presented, with emphasis on options recently added to the code. Among the new options are an energy-dependent direct-capture component for capture cross sections, a crystal-lattice model for Doppler broadening, improvements in the fitting procedure to incorporate more of the experimental uncertainties and covariances, streamlined input, and enhanced ENDF-related capabilities. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We propose to use population synthesis studies as an independent approach to test the physics governing the star cooling. Theoretical Log N-Log S distributions depend on the assumed neutron star thermal evolution. We have computed distributions for several different cooling scenarios and found that comparison with the observed Log N-Log S of isolated neutron stars is effective in discriminating among cooling models. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The neutron cross-section and the complete fusion cross-section data is available for 6Li+152Sm→158Tb*→A1+A2 reaction at various lab energies ranging from ELab = 20 MeV -40 MeV, where the effects of target deformation and projectile break-up are addressed. Here in this work, we have emphasized on the deformation (and orientation) effects in the decay of 158Tb* nucleus in the framework of dynamical cluster decay model (DCM). The cross-sections obtained through DCM based calculations find nice agreement with the reported experimental data across the Coulomb barrier. The available cross-sections are fitted for spherical and β2-deformed fragmentation paths with the effects of static β2(0) and dynamic β2(T) deformations also included into it. This provides a nice description of the role of deformation in the decay of 158Tb* nucleus. Besides this, comparative analysis with equatorial (compact) and polar (non-compact) configurations is worked out. As the polar orientations start appearing at sub-barrier energies, so the effect of deformations and orientations is illustrated at lowest incident energy, ELab = 20 MeV (or equivalently at Ec.m. = 19.2 MeV). [ABSTRACT FROM AUTHOR]

The newly established bands in 151,153Pr are studied by using projected shell model approach. The calculated level scheme is in good agreement with the experimental data and the reflection-symmetric-quasi-particle rotor model. The present calculations predict proton g9/2, K = 9/2 band as the lowest positive parity band in both the nuclei. [ABSTRACT FROM AUTHOR]

Using fragment-separator COMBAS [1] in forward-angle measurements the velocity, isotopic and element distributions of products with Z<7 in 11B(33 AMeV)+9Be reaction have been studied. The yields of 6,8He and 9Li isotopes on the 9Be thick target (332.6 mg/cm2) as a function of momentum acceptance of fragment -separator COMBAS have been measured. The production rates per 1pμA of the primary beam of exotic nuclei of 6He(6.9·105 pps), 8He(2·104 pps) and 9Li(4.3·10 5pps) which can be used as secondary radioactive beams of halo -like nuclei have been determined. The two-neutron halo nuclei 6,8He and 9Li are of great current interest both as very neutron-rich nuclei with a significant neutron skin and in understanding the interactions of very neutron-rich nuclei. The 9Li beam may be helpful in understanding of sub barrier fusion enhancement independent of the presence of the halo nucleons in used neutron—rich projectiles. [ABSTRACT FROM AUTHOR]

The latest results from the HARP, MIPP and NA61 Hadron Production Experiments are reviewed and their implications for neutrinos physics experiments are discussed. We emphasize three neutrino sources: accelerator-based neutrino beams, advanced neutrino sources and atmospheric neutrinos. Finally, prospects from additional forthcoming hadron production measurements are presented. [ABSTRACT FROM AUTHOR]

The spectroscopy of fission fragments, obtained by the 18O+208Pb fusion-fission reaction at 85 MeV bombarding energy, has been performed with the Euroball IV γ-array. High-spin states in many neutron-rich Se, Br, Kr and Rb of the 78Ni region nuclei have been identified for the first time. Several physical aspects which govern the nuclear structure in this mass region are underlined thanks to the new results. Among those, empirical values of the residual proton-neutron interactions have been extracted for the πf5/2xvd5/2 and πp3/2xvd5/2 configurations. [ABSTRACT FROM AUTHOR]

Two experimental setups have been used to study excited states of neutron-rich nuclei in the A∼100 region. Extended level schemes and lifetime measurements were obtained using deep-inelastic and fusion-fission reactions with the CLARA-PRISMA spectrometer and the Ge-array GASP respectively. Experimental information from GASP has been used to complement the CLARA-PRISMA experiment. Time spectra have been used to measure the lifetimes of isomeric states. Preliminary results are presented for 89Rb. [ABSTRACT FROM AUTHOR]

The properties of cylindrical 1.5″×1.5″LaCl3:Ce scintillation detectors were determined. For the energy resolution values between 3.8 and 4.2% at 662 keV were observed, following the expected E-1/2 behavior. The intrinsic full peak efficiency was determined to be more than 50% higher than for NaI:Tl detectors of same size. The observed intrinsic timing resolution for 60Co was estimated to 441 ps and the intrinsic activity of the lanthanum crystals was assessed. [ABSTRACT FROM AUTHOR]

Theoretical and numerical studies of prompt fission neutrons are presented. The main results of the Los Alamos model often used in nuclear data evaluation work are reviewed briefly, and a preliminary assessment of uncertainties associated with the evaluated prompt fission neutron spectrum for n (0.5 MeV)+239Pu is discussed. Advanced modeling of prompt fission neutrons is done by Monte Carlo simulations of the evaporation process of the excited primary fission fragments. The successive emissions of neutrons are followed in the statistical formalism framework, and detailed information, beyond average quantities, can be inferred. This approach is applied to the following reactions: 252Cf(sf), nth+239Pu, n(0.5 MeV)+235U, and 236Pu(sf). A discussion on the merits and present limitations of this approach concludes this presentation. [ABSTRACT FROM AUTHOR]

Angular distributions of light charged particles relative to the momentum of the light fission fragment were studied in ternary fission induced by cold polarized neutrons. It was discovered that the angular distribution is asymmetric with respect to a plane determined by the direction of incident neutron spin and the light fragment momentum. The violation of the mirrorlike symmetry was established at the level of ∼10-2–10-4 for three reactions studied: 233U(n,f), 235U(n,f) and 239Pu(n,f). In spite of the smallness of the effects the neutron spin flip method allowed to make reliable measurements. The current status of the experimental studies of the effect and its interpretation are presented. Perspectives for further studies of the new phenomenon are discussed. [ABSTRACT FROM AUTHOR]

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. A constraint is placed on the two independent components of the quadrupole moment in order to self-consistently explore the shape phase space of nuclear configurations. The scheme employed naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state can be calculated across phase transitions from lower densities (where one dimensional Hartree-Fock suffices) through to uniform nuclear matter without recourse to interpolation techniques between density regimes described by different physical models. [ABSTRACT FROM AUTHOR]

In this talk I shall explain some basic concepts of baryogenesis and leptogenesis theory, and a new idea of experimental method of verification of fundamental ingredients of leptogenesis theory; the Majorana nature and the absolute magnitude of neutrino masses. Both of these are important to the quest of physics beyond the standard theory, and have far reaching implications irrespective of any particular medel of leptogenesis. If this new method works ideally, there is even a further possibility of detecting relic neutrinos. [ABSTRACT FROM AUTHOR]

The Detector for Advanced Neutron Capture Experiments (DANCE) is a 4π BaF2 array consisting of 160 active detector elements. The primary purpose of the array is to perform neutron capture cross section measurements on small (>=100 μg) and/or radioactive (<=100 mCi) species. The measurements made possible with this array will be useful in answering outstanding questions in the areas of national security, threat reduction, nuclear astrophysics, advanced reactor design and accelerator transmutation of waste. Since the commissioning of DANCE we have performed neutron capture cross section measurements on a wide array of medium to heavy mass nuclides. Measurements to date include neutron capture cross sections on 241,243Am, neutron capture and neutron-induced fission cross sections and capture-to-fission ratio (α = σγ/σf) for 235U using a new fission-tagging detector as well as neutron capture cross sections for several astrophysics branch-point nuclei. Results from several of these measurements will be presented along with a discussion of additional physics information that can be extracted from the DANCE data. [ABSTRACT FROM AUTHOR]

High resolution measurements using the (3He,n) reaction are used to determine excitation energies of astrophysically important states. Further, spins can be assigned to these states by comparing the measured differential cross sections to Hauser-Feshbach cross sections. The astrophysical reaction rates are then calculated using the experimental values. Reference [1] is an example of such measurements. Absolute values of the astrophysical S factors and cross sections are calculated from measurements using the (d,n) reaction at low incident energies. Reference [2] is an example of such measurements. [ABSTRACT FROM AUTHOR]

A series of recoil distance Doppler-shift lifetime measurements have been carried out to probe collectivity and configuration mixing of different shapes in the vicinity of neutron mid-shell Pb nuclei. Lifetime measurements of 186Pb and 194Po, the first ever utilizing the recoil-decay tagging method, probed the collectivity of coexisting prolate and oblate shapes in this region. Futher lifetime measurements of excited states in 180Hg, 182Hg and 196Po have been carried out. [ABSTRACT FROM AUTHOR]

Dipole strength distributions were determined for the neutron-rich nuclei 129–132Sn and 133,134Sb from electromagnetic excitation in an experiment using the FRS-LAND setup. For all nuclei, a sizeable fraction of “pygmy” dipole strength at excitation energies well below the giant dipole resonance was observed. The integrated low-lying dipole strength of the nuclei with low neutron separation energies can be compared to results for stable nuclei (e.g. N = 82 isotopes) determined for the energy regime of 5–9 MeV. A clear increase of the dipole strength with increasing asymmetry of the nuclei is observed. Comparing the ratio of the low-lying dipole over the giant dipole strength to recent relativistic mean field calculations, values for the parameters a4 and p0 of the symmetry energy and for the neutron skin thickness are derived. Averaged over 130Sn and 132Sn we extract ā4 = 31.8±1.3 MeV and p0 = 2.2±0.5 MeV/fm3. The neutron skin sizes are determined to Rn-Rp = 0.23±0.03 fm and 0.24±0.03 fm for 130Sn and 132Sn, respectively. For 208Pb a neutron skin thickness of Rn-Rp = 0.18±0.035 fm follows, when applying the same method and using earlier published experimental findings on the dipole strength. [ABSTRACT FROM AUTHOR]

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 a two-particle-two-hole (2p2h) correlation, which cannot be treated with a standard mean-field 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 as 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 23F. 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. [ABSTRACT FROM AUTHOR]

We present results from two recent sets of experiments to demonstrate the continuing impact of neutron time-of-flight data on the underlying assumptions and parameters of compound nuclear models. [ABSTRACT FROM AUTHOR]

We have indirectly determined the 237Np(n,f) cross section over an equivalent neutron energy range from 10 to 20 MeV using the surrogate reaction 238U(3He,tf). A self-supporting ∼761 μg/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS) consisted of two 140 μm and one 1000 μm Micron S2 type silicon detectors. These results were compared with the 237Np(n,f) cross section data from the direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. [ABSTRACT FROM AUTHOR]

The blocking technique in single crystals is a direct method to investigate the presence of long fission time components. With a lead beam impinging on a germanium single crystal, we tried to produce compound nuclei (CN) with atomic number Z = 114 at high excitation energy. Blocking patterns for reaction products are reconstructed with position sensitive detectors at 20 ° relative to the beam direction. The Z and the energies of all products are measured with ΔE-E telescopes of the 4π INDRA array, so that all reaction channels are unambiguously identified. With this setup, we can reach long fission times (>10-18 s) that can be associated with CN fissions. However, in contrast to previous experiments in which such long fission times could be measured for Z = 120 and 124, no hint of long lifetimes within our sensitivity limit for Z = 114 was observed, which may be due to the neutron deficiency of the formed isotopes. [ABSTRACT FROM AUTHOR]

The systematics of the πh11/2xνh11/2 and πh11/2xνs1/2 isomeric configurations were studied for the odd-Z N = 77 isotones near the proton dripline. The spin and parity of Iπ = 8+ and 5- were deduced for the isomers in 140Eu and 142Tb. No evidence for the expected 1+ ground-state was found in the 144Ho decay data. The proton emission from 146Tm was restudied and the spin and parity values of Iπ = 10+ and 5- were established for 146mTm and 146gsTm, respectively. The interpretation of the observed decay properties and structure of the proton-emitting states was made by accounting for deformation and proton and neutron coupling to the core excitations. [ABSTRACT FROM AUTHOR]

N-dimensional gravity is analized in the context of recent work on “large” supplementary dimensions. A simple derivation of the compactification radii for additional dimensions in the universe is made, as a function of the Planck and the electro-weak scales. It is argued that the modified gravitational force would give rise to effects that might be within the detection range of dedicated neutron experiments. An analysis suggests that neutron scattering off atomic nuclei with null spin may provide an experimental test for these ideas. [ABSTRACT FROM AUTHOR]

The cross sections and spin observables of the pd elastic scattering have been measured at 392 MeV. The results are compared with the prediction of Faddeev calculations with and without including a three nucleon force. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Investigation of unbound nuclear systems 9He, 7H and 4n was performed at GANIL-SPIRAL using the 8He beam at 15.3 A MeV and a CD2 target. The missing mass spectra were deduced from kinetic energies and emission angles of light ejectiles detected by the Silicon array MUST. In addition to previously known low-lying narrow resonant states in 9He, the d(8He,p) reaction displays a structure just above neutron emission threshold, identified with the “true” ground state of 9He. The analysis of angular distributions shows that the inversion of s1/2 and p1/2 neutron shells previously observed in 11Be and 10Li also exists in the lightest N=7 isotone 9He. The d(8He,3He) and d(8He,6Li) reactions were used to search for resonant states in the t+4n (7H) and 4n systems, respectively. The missing mass spectrum of the 4n system does not give evidence for the existence of a bound “tetraneutron”. However the comparison with the results of 5-body phase-space calculations emphasizes the existence of correlations in the 4n system. The broad structure observed at ≃2 MeV above the t+4n emission threshold is proposed to be the ground state of 7H. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

A systematic for the light proton rich nuclei with constant TZ = -3/2 isospin is proposed, where a survey on their structure have shown interesting features. Preliminary results of a re-analysis on the sctructure of 13O nucleus is also presented. This 13O nucleus have been investigated by the 3-neutron pick up (3He,6He) reaction, and new levels have been assigned for this nucleus. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The energy spectra and relative transition rates of 176,178,180Os were found to be very similar to the values calculated in the framework of the critical point symmetry X(5). In order to enable more stringent tests, including also absolute transition probabilities, two coincidence RDDS lifetime measurements were performed at the Laboratori Nazionali di Legnaro with the GASP spectrometer using the 152,154Sm(29Si,5n)176,178Os reactions. The deduced transition quadrupole moments in 178Os agree well with the X(5) predictions. For 176Os only preliminary results were obtained so far. These preliminary data support an X(5) like structure also in the case of 176Os. The experimental data of both nuclei are compared to calculations in the framework of the interacting boson model (IBM) and of the general collective model (GCM). © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Recent years have seen an extraordinary breakthrough in neutrino physics. Compelling experimental evidence indicates that, contrary to earlier believes, this fundamental particles have non zero masses and mix. Such properties are manifested in the oscillation phenomena in neutrino fluxes produced within the Sun, by cosmic rays, and in nuclear plants on the Earth, among other astrophysical and terrestrial sources. In these lecture we provide a short introduction to neutrino properties, mainly intended to give some basic elements of the physics of neutrino oscillations for beginners. We also discuss some of the theoretical questions raised on particle physics by the discovery of neutrino masses and mixings. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The discovery of the currently known most neutron- and proton-rich nuclei is compiled. The compilation includes the year and method of discovery of the last known bound and the first unbound nuclei along the neutron and proton driplines. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]