Parental Break-Ups and Stress

DEFF Research Database (Denmark)

Dissing, Agnete S.; Dich, Nadya; Nybo Andersen, Anne-Marie

2017-01-01

Background: Parental break-up is wide spread, and the effects of parental break-up on children’s well-being are known. The evidence regarding child age at break-up and subsequent family arrangements is inconclusive. Aim: to estimate the effects of parental break-up on stress in pre-adolescent chi......Background: Parental break-up is wide spread, and the effects of parental break-up on children’s well-being are known. The evidence regarding child age at break-up and subsequent family arrangements is inconclusive. Aim: to estimate the effects of parental break-up on stress in pre......-adolescent children with a specific focus on age at break-up and post-breakup family arrangements. Methods: We used data from the Danish National Birth Cohort. Participants included 44 509 children followed from birth to age 11. Stress was self-reported by children at age 11, when the children also reported...... on parental break-up and post break-up family arrangements. Results: Twenty-one percent of the children had experienced a parental break-up at age 11, and those who had experienced parental break-up showed a higher risk of stress (OR:1.72, 95%CI:1.55;1.91) regardless of the child’s age at break-up. Children...

11Li structural information from inclusive break-up measurements

Directory of Open Access Journals (Sweden)

Fernández-García J. P.

2015-01-01

Full Text Available Structure information of 11Li halo nucleus has been obtained from the inclusive break-up measurements of the 11Li+208Pb reactions at energies around the Coulomb barrier (Elab = 24.3 and 29.8 MeV. The effective break-up energy and the slope of B(E1 distribution close to the threshold have been extracted from the experimental data.

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

International Nuclear Information System (INIS)

Marquez, L.

1966-01-01

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

Projectile break-up of 14N at 62,7 MeV

International Nuclear Information System (INIS)

Bozek, E.; Cassagnou, Y.; Dayras, R.; Legrain, R.; Pagano, A.; Rodriguez, L.; Lanzano, G.; Palmeri, A.; Pappalardo, G.

1983-01-01

In plane and out of plane angular correlations between light particles and heavy ions have been measured in the reaction 14 N + 12 C at 62.7 MeV bombarding energy. Special attention has been given to the break-up of 14 N into 13 C + p, 12 C + d and 10 B + α. The observed correlations are consistent with sequential break-up of the 14 N projectile. A Monte-Carlo calculation assuming isotropic emission of particles in the rest frame of the projectile from well defined states in 14 N is in good agreement with the experimental angular correlations. From a comparison between calculated and experimental boron and carbon single energy spectra, it appears that after transfer reactions, sequential break-up of 14 N is the dominant process to produce these nuclei

On the Chew-Low plot as a limiting case of the distorted wave theory of break-up reactions

International Nuclear Information System (INIS)

Baur, G.

1976-01-01

A recently developed formulation of break-up reactions in the frame of the DW approximation is compared to a theory of Chew and Low given in 1958. By suitably rewriting the DWBA matrix element, one can pick out a term, dominant for certain kinematical conditions, which is identical to the expression given by Chew and Low. (orig.) [de

General description of few-body break-up processes at threshold

International Nuclear Information System (INIS)

Barrachina, R.O.

2004-01-01

Full text: In this communication we present a general description of the behavior of fragmentation processes near threshold by analyzing the break-up into two, three and N bodies in steps of increasing complexity. In particular, we describe the effects produced by an N-body threshold behavior in N+1 body break-up processes, as it occurs in situations where one of the fragments acquires almost all the excess energy of the system. Furthermore, we relate the appearance of cusps and discontinuities in single-particle multiply differential cross sections to the threshold behavior of the remaining particles, and apply these ideas to different systems from atomic, molecular and nuclear collision physics. We finally show that, even though the study of ultracold collisions represents the direct way of gathering information on a break-up system near threshold, the analysis of high-energy collisions provides an alternative, and sometimes advantageous, approach

Nuclear fragmentation reactions in extended media studied with Geant4 toolkit

Energy Technology Data Exchange (ETDEWEB)

Pshenichnov, Igor, E-mail: pshenich@fias.uni-frankfurt.d [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow (Russian Federation); Botvina, Alexander [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Science, 117312 Moscow (Russian Federation); Mishustin, Igor [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, 123182 Moscow (Russian Federation); Greiner, Walter [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany)

2010-03-15

It is well-known from numerous experiments that nuclear multifragmentation is a dominating mechanism for production of intermediate mass fragments in nucleus-nucleus collisions at energies above 100AMeV. In this paper we investigate the validity and performance of the Fermi break-up model and the statistical multifragmentation model implemented as parts of the Geant4 toolkit. We study the impact of violent nuclear disintegration reactions on the depth-dose profiles and yields of secondary fragments for beams of light and medium-weight nuclei propagating in extended media. Implications for ion-beam cancer therapy and shielding from cosmic radiation are discussed.

Nuclear fragmentation reactions in extended media studied with Geant4 toolkit

International Nuclear Information System (INIS)

Pshenichnov, Igor; Botvina, Alexander; Mishustin, Igor; Greiner, Walter

2010-01-01

It is well-known from numerous experiments that nuclear multifragmentation is a dominating mechanism for production of intermediate mass fragments in nucleus-nucleus collisions at energies above 100AMeV. In this paper we investigate the validity and performance of the Fermi break-up model and the statistical multifragmentation model implemented as parts of the Geant4 toolkit. We study the impact of violent nuclear disintegration reactions on the depth-dose profiles and yields of secondary fragments for beams of light and medium-weight nuclei propagating in extended media. Implications for ion-beam cancer therapy and shielding from cosmic radiation are discussed.

Break-up reactions: theoretical aspects

International Nuclear Information System (INIS)

Baye, D.

2007-01-01

Breakup reactions are one of the main tools for the study of exotic nuclei. In particular, Coulomb breakup is expected to provide information on spectroscopic properties of halo nuclei and on astrophysical S factors for radiative-capture reactions. The simplest studies are based on perturbation theory and especially on its first order. However the validity of the first-order approximation may be limited for extended systems such as halo nuclei and its conditions are not always satisfied in existing experiments. More elaborate reaction models are available: resolution of the semi-classical time-dependent Schroedinger equation, eikonal and dynamical eikonal approximations, method of coupled discretized-continuum channels (CDCC). These methods are reviewed and summarized. Their interest and limitations are discussed. The Be 11 and B 8 breakups are treated as examples of the various approximations. (author)

Hard Break-Up of Two-Nucleons and QCD Dynamics of NN Interaction

International Nuclear Information System (INIS)

Sargsian, Misak

2008-01-01

We discus recent developments in theory of high energy two-body break-up of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model (HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon between two outgoing nucleons. This final state hard rescattering can be expressed through the hard NN scattering amplitude. Within HRM we discuss hard break-up reactions involving D and 3 He targets and demonstrate how these reactions are sensitive to the dynamics of hard pn and pp interaction. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

General description of few-body break-up processes at threshold

International Nuclear Information System (INIS)

Barrachina, R.O.

2005-01-01

In this communication we describe the effects produced by an N-body threshold behavior in N + 1 body break-up processes, as it occurs in situations where one of the fragments acquires almost all the excess energy of the system. Furthermore, we relate the appearance of discontinuities in single-particle multiply differential cross sections to the threshold behavior of the remaining particles, and describe the applicability of these ideas to different systems from atomic, molecular and nuclear collision physics. We finally show that, even though the study of ultracold collisions represents the direct way of gathering information on a break-up system near threshold, the analysis of high-energy collisions provides an alternative, and sometimes advantageous, approach

Mechanisms of Li-projectile breakup-up

International Nuclear Information System (INIS)

Rebel, H.; Srivastava, D.K.

1990-08-01

Various experimental and theoretical features observed in recent studies of break-up of 6 Li and 7 Li projectiles in the field of atomic nuclei are discussed, in particular for the transitional energy regime of 10-30 MeV/amu. The discussion is organized as three independent lectures presented at the International School on Nuclear Physics, Kiev (UkSSR), 28 May - 8 June, 1990. After a survey on the main experimental facts and on the basic reaction mechanisms, current theoretical approaches are illustrated by an application to the analysis of elastic break-up of 156 MeV 6 Li projectiles. Finally Coulomb break-up is discussed as a novel tool of laboratory nuclear astrophysics. (orig.) [de

Cross Sections Calculations of ( d, t) Nuclear Reactions up to 50 MeV

Science.gov (United States)

Tel, E.; Yiğit, M.; Tanır, G.

2013-04-01

In nuclear fusion reactions two light atomic nuclei fuse together to form a heavier nucleus. Fusion power is the power generated by nuclear fusion processes. In contrast with fission power, the fusion reaction processes does not produce radioactive nuclides. The fusion will not produce CO2 or SO2. So the fusion energy will not contribute to environmental problems such as particulate pollution and excessive CO2 in the atmosphere. Fusion powered electricity generation was initially believed to be readily achievable, as fission power had been. However, the extreme requirements for continuous reactions and plasma containment led to projections being extended by several decades. In 2010, more than 60 years after the first attempts, commercial power production is still believed to be unlikely before 2050. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. In the fusion reactor, tritium self-sufficiency must be maintained for a commercial power plant. Therefore, for self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( d, t) nuclear reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. Since the experimental data of charged particle induced reactions are scarce, self-consistent calculation and analyses using nuclear theoretical models are very important. In this study, ( d, t) cross sections for target nuclei 19F, 50Cr, 54Fe, 58Ni, 75As, 89Y, 90Zr, 107Ag, 127I, 197Au and 238U have been investigated up to 50 MeV deuteron energy. The excitation functions for ( d, t) reactions have been calculated by pre-equilibrium reaction mechanism. Calculation results have been also compared with the available measurements in

Study of the deuteron break-up with protons and neutrons

International Nuclear Information System (INIS)

Kumpf, H.; Moeller, K.; Moesner, J.; Schmidt, G.

1977-06-01

A review is given on the present situation and the results obtained in the experimental and theoretical investigation of the break-up of deuterons by protons and neutrons at bombarding energies up to 50 MeV. The nonrelativistic three-particle kinematics, experimental techniques and the basic theoretical equations for three particle scattering are described and the most important experimental results of the last years are discussed together with theoretical interpretation. It is shown that the reaction mechanism of the N-d break-up is well understood and that one can extract two-particle low energy scattering parameters (e.g., the n-n scattering length) with good accuracy. But despite of a relatively good agreement between experimental spectra and theoretical calculations (except polarisation measurements) no reliable quantitative information on the off-shell behaviour of the two-particle interaction and on three-body forces can be obtained at present. (author)

Study of projectile break-up process at intermediate energies

International Nuclear Information System (INIS)

Kumar, Harish; Parashari, Siddharth; Tali, Suhail A.

2016-01-01

The projectile break-up reactions are explained in terms of incomplete fusion or massive transfer reactions leading to the formation of composite system with less mass, charge and excitation energy, as compared to the complete fusion (CF) process. Since, the existing theoretical models are not applicable to reproduce the experimentally measured ICF, data satisfactory below 10 MeV/nucleon energies; thereby the study of the role of the entrance channel parameters in the fusion reactions is still a relevant problem in establishing the explicit inference regarding the influence of ICF on CF at 4-7 MeV/nucleon energies. Recently reported some studies have also shown that alpha Q-value is also an important parameter which affects the onset of ICF and conflict with the suggestion of Morgenstern et al. Keeping in view the recent aspects, to provide more strength to the aspect of projectile-target mass-asymmetry effect, role of non α-cluster projectile over α-cluster projectile, the present work has been carried out which will be useful to understand a clearer picture about the conflict between mass-asymmetry and projectile structure effect on break-up fusion process. As such, excitation function measurement of residues produced in 13 C + 175 Lu system has been carried out in a series of experiments of comparative study using α-cluster as well as non α-cluster projectiles with deformed heavier target nuclei at lower projectile energies ≈ 4-7 MeV/nucleon

Deuteron color degrees of freedom and deuteron break-up at high energy

International Nuclear Information System (INIS)

Kobushkin, A.P.

1992-01-01

Deuteron break-up reactions are analysed from a QCD-motivated point of view. Production of a nucleon with hard momentum is considered as a result of high gluon exchange between three quark clusters in hidden-color component of deuteron wave function. It is shown that the model reproduces well the nucleon momentum distribution extracted from (d,p)-reaction at high energy as well as the tensor analysing powers T 20 of this reaction and of the reaction of elastic pd-backward scattering. 19 refs.; 2 figs.; 1 tab. (author)

Determination of the 13N(p,γ)14O reaction rate through the Coulomb break-up of a 14O radioactive beam

International Nuclear Information System (INIS)

Kiener, J.; Lefebvre, A.; Aguer, P.; Bogaert, G.; Coc, A.; Pasquier, G.; Thibaud, J.P.; Bacri, C.O.; Bimbot, R.; Borderie, B.; Clapier, F.; Fortier, S.; Rivet, M.F.; Stephan, C.; Tassan-Got, L.; Disdier, D.; Kraus, L.; Linck, I.; Grunberg, C.; Laurent, F.S.

1993-01-01

In stellar-evolution models, the 13 N(p,γ) 14 O reaction plays an important role in the hot CNO cycle. Its reaction rate depends directly on the magnitude of the radiative width of the 5.17 MeV level in 14 O. That width has been measured using the Coulomb break-up technique. A 70 MeV/u 14 O beam was excited in the Coulomb field of a 208 Pb target, the 13 N and proton fragments being recorded using a magnetic spectrometer and CsI scintillators, respectively. The experimental value Γ γ =2.4±0.9 eV in overall agreement with other recent measurements. (orig.)

Nuclear effects in {sup 8}B dissociation

Energy Technology Data Exchange (ETDEWEB)

Kido, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-07-01

The break-up reaction of the nucleus on proton drip-line is investigated. A time-dependent Schroedinger equation for the relative motion between a weakly bound proton and core nucleus is numerically solved by treating the Coulomb+nuclear fields of a target as an external field. The theory is applied to the break-up reaction {sup 8}B + {sup 208}Pb {yields} {sup 7}Be + p + {sup 208}Pb. (author)

Catalysis of Nuclear Reactions by Electrons

Science.gov (United States)

Lipoglavšek, Matej

2018-01-01

Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1H(19F,αγ)16O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2H(p,γ)3He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.

Supramolecular Systems and Chemical Reactions in Single-Molecule Break Junctions.

Science.gov (United States)

Li, Xiaohui; Hu, Duan; Tan, Zhibing; Bai, Jie; Xiao, Zongyuan; Yang, Yang; Shi, Jia; Hong, Wenjing

2017-04-01

The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

187Re - 232Th - 238U nuclear geochronometry: constraining magmatism in East-Antarctica and the break-up of Gondwana

Science.gov (United States)

Roller, Goetz

2017-04-01

187Re - 232Th - 238U nuclear geochronometry is a new dating method for astronomy, earth and planetary sciences [1-4]. Nucleogeochronometric Rhenium-Osmium two-point-isochron (TPI) ages are calculated using a nuclear geochronometer as one data point in a two-point-isochron diagram [5-7]. The IVREA chronometer, for example, is one of five terrestrial nuclear geochronometers identified so far [8]. Here, it is used to constrain the magmatism of the Ferrar flood basalt province, which has been related to continental rifting and the break-up of Gondwana in the Jurassic.TPI ages for seven (basaltic) andesite whole rock samples from the Prince Albert Mountains (Victoria Land, Antarctica) are calculated. An isochron age of 172 ± 5 Ma (187Os/188Osi = 0.194 ± 0.023) has previously been published for these rocks [9]. Initial TPI 187Os/188Osi ratios show only minor scatter between 187Os/188Osi = 0.2149 ± 0.0064 and 187Os/188Osi = 0.22231 ± 0.00080, in agreement with the enigmatic, suprachondritic 187Os/188Osi = 0.194 ± 0.023 from the isochron [9]. TPI ages for the Mount Joyce samples range from 125.4 ± 9.9 Ma to 139 ± 17 Ma and thus constrain the youngest magmatic event(s) in the Transantarctic Mountains. For the Thumb Point basalt, a TPI age of 219 ± 81 Ma is calculated. Despite of its large uncertainty, the age itself is in agreement with the Triassic 224 Ma and 240 Ma events reported from North Patagonia [10]. The TPI age of 186.1 ± 8.1 Ma from the Ricker Hill basalt can be clearly distinguished from the Mount Murray TPI age of 158 ± 14 Ma, while at Brimstone Peak two TPI age groups of 155 ± 14 Ma and 175.3 ± 3.1 Ma are observed. From this it may be concluded that the seven TPI ages indicate episodic magmatic activity in East-Antarctica between 125 Ma and 219 Ma, leading to the break-up of Gondwana. This picture is consistent with the geochronology of the Antarctic Peninsula, Patagonia, the Karoo and the Ferrar mafic rocks [10]. Thus, besides constraining

Inelastic collisions of heavy ions and their reaction mechanisms; Collisions inelastiques d'ions lourds et mecanismes de reaction

Energy Technology Data Exchange (ETDEWEB)

Scarpaci, J.A

2004-06-01

This work is dedicated to the study of inelastic collisions of heavy ions. Most experiments took place in Ganil facility. The 2 first chapters introduce the notion of inelastic scattering of heavy ions. The third chapter deals with target excitation, giant monopolar or dipolar or quadrupolar resonances ant the multi-phonon concept and presents relevant experimental results from the Ca{sup 40} + Ca{sup 40} nuclear reaction at 50 MeV/A. The fourth chapter is dedicated to nuclear processes involved in inelastic collisions: pick-up break-up mechanisms, the angular distribution of emitted protons and the towing mode. These notions are applied to the reaction Zr{sup 90}(Ar{sup 40}, Ar{sup 40}'). The fifth chapter presents the solving of the time dependent Schroedinger equation (TDSE) applied to the wave function of a particle plunged in a variable potential. TDSE solving is applied to the break-up of Be{sup 11}. These calculations have been validated by comparing them with experimental results from the nuclear reaction Ti{sup 48}(Be{sup 11}, Be{sup 10} + n + {gamma}) that is described in the chapter 6. The last chapter presents the advantages of inelastic scattering considered as a tool to study exotic nuclei.

Activation cross-section data for -particle-induced nuclear reactions ...

Indian Academy of Sciences (India)

B M ALI

2018-02-20

particle-induced nuclear reactions on natural vanadium up to 20 MeV. It should be mentioned that this study represents a part of (a supplement) systematical study of charged particles-induced nuclear reactions. Earlier studies were.

The evolution of the break preclusion concept for nuclear power plants in Germany

Energy Technology Data Exchange (ETDEWEB)

Schulz, H. [Gesellschaft fuer Anlagen- und Reaktorsicherheit, Koeln (Germany)

1997-04-01

In the updating of the Guidelines for PWR`s of the {open_quotes}Reaktor-Sicherheitskommission{close_quotes} (RSK) in 1981 the requirements on the design have been changed with respect to the postulated leaks and breaks in the primary pressure boundary. The major change was a revision in the requirements for pipe whip protection. As a logical consequence of the {open_quotes}concept of basic safety{close_quotes} a guillotine type break or any other break type resulting in a large opening is not postulated any longer for the calculation of reaction and jet forces. As an upper limit for a leak an area of 0, 1 A (A = open cross section of the pipe) is postulated. This decision was based on a general assessment of the present PWR system design in Germany. Since then a number of piping systems have been requalified in the older nuclear power plants to comply with the break preclusion concept. Also a number of extensions of the concept have been developed to cover also leak-assumptions for branch pipes. Furthermore due considerations have been given to other aspects which could contribute to a leak development in the primary circuit, like vessel penetrations, manhole covers, flanges, etc. Now the break preclusion concept originally applied to the main piping has been developed into an integrated concept for the whole pressure boundary within the containment and will be applied also in the periodic safety review of present nuclear power plants.

The Beam Break-Up Numerical Simulator

International Nuclear Information System (INIS)

Travish, G.A.

1989-11-01

Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs

Firm break-up and performance

Czech Academy of Sciences Publication Activity Database

Kočenda, Evžen; Hanousek, Jan

2012-01-01

Roč. 13, č. 2 (2012), s. 121-143 ISSN 1435-6104 R&D Projects: GA ČR GA402/09/1595 Institutional support: PRVOUK-P23 Keywords : break-up of firms * corporate performance * ownership changes Subject RIV: AH - Economics Impact factor: 0.588, year: 2012

Breaking Up is Hard to Do… Why do long-term couples decide to break-up?

Czech Academy of Sciences Publication Activity Database

Vohlídalová, Marta

2009-01-01

Roč. 7, 7-8 (2009), s. 5-7 ISSN 1214-1720 Grant - others:GA UK(CZ) 9864/2009 Institutional research plan: CEZ:AV0Z70280505 Keywords : family * divorce s * unmarried cohabitation break-ups Subject RIV: AO - Sociology, Demography http://www.socioweb.cz

Nuclear reactions

International Nuclear Information System (INIS)

Lane, A.M.

1980-01-01

In reviewing work at Harwell over the past 25 years on nuclear reactions it is stated that a balance has to be struck in both experiment and theory between work on cross-sections of direct practical relevance to reactors and on those relevant to an overall understanding of reaction processes. The compound nucleus and direct process reactions are described. Having listed the contributions from AERE, Harwell to developments in nuclear reaction research in the period, work on the optical model, neutron capture theory, reactions at doorway states with fine structure, and sum-rules for spectroscopic factors are considered in more detail. (UK)

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

Energy Technology Data Exchange (ETDEWEB)

Marquez, L

1966-07-01

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

Charge symmetry breaking nuclear forces and the properties of nuclear matter

International Nuclear Information System (INIS)

Haensel, P.

1977-01-01

The charge symmetry breaking (CSB) component of the nuclear forces yields the charge asymmetric term Esub(a)(N-Z)/A in the nuclear binding energy of nuclear matter. Calculation performed with several models of the CSB nuclear forces, and accounting for the strong short-range two-body correlations, gives Esub(a) approximately -0.2 MeV at the normal nuclear density. The charge asymmetry of the effective nucleon-nucleon interaction is determined primarily by the CSB nuclear forces at the neutron excess, observed in finite nuclei. The exclusion principle and dispersion (self-consistency) effects of the nuclear medium decrease this charge asymmetry. (author)

Population of Metastable States in Stable Hafnium and Ytterbium Nuclei via Beam Break-up

International Nuclear Information System (INIS)

Malwela, T.; Ntshangase, S.S.; Shirinda, O.; Bark, R.A.; Gueorguieva, E.; Lawrie, J.J.; Mullins, S.M.; Murray, S.H.T.; Sharpey-Schafer, J.F.; Gal, J.; Kalinka, G.; Krasznahorkay, A.; Molnar, J.; Nyako, B.M.; Timar, J.; Zolnai, L.; Hlatshwayo, T.; Juhasz, K.; Komati, F.S.; Scheurer, J.N.

2005-01-01

The ''Chessboard'' section of the DIAMANT charged-particle array has been coupled with the AFRODITE γ-ray spectrometer at the iThemba Laboratory for Accelerator Based Sciences. Charged-particle-γ-ray coincidence data were recorded during the bombardment of a 176Yb target with a 13C beam at an energy of 90 MeV. The purpose of the investigation was to study the population of metastable states in hafium nuclei via incomplete fusion reactions in which the beam breaks up due to its α-cluster character. Of note was the observation of the band based on the Kπ = 16+, T1/2 = 31 year isomer in 178Hf to its 19+ member. Also, decays from the high-K isomeric states in 174Yb and 176Yb. which were populated via 3αxn channels, indicative of complete break-up of the 13C beam

DEPENDENCE OF X-RAY BURST MODELS ON NUCLEAR REACTION RATES

Energy Technology Data Exchange (ETDEWEB)

Cyburt, R. H.; Keek, L.; Schatz, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Amthor, A. M. [Department of Physics and Astronomy, Bucknell University, Lewisburg, PA 17837 (United States); Heger, A.; Meisel, Z.; Smith, K. [Joint Institute for Nuclear Astrophysics (JINA), Michigan State University, East Lansing, MI 48824 (United States); Johnson, E. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2016-10-20

X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars, and reliable burst models are needed to interpret observations in terms of properties of the neutron star and the binary system. We investigate the dependence of X-ray burst models on uncertainties in (p, γ ), ( α , γ ), and ( α , p) nuclear reaction rates using fully self-consistent burst models that account for the feedbacks between changes in nuclear energy generation and changes in astrophysical conditions. A two-step approach first identified sensitive nuclear reaction rates in a single-zone model with ignition conditions chosen to match calculations with a state-of-the-art 1D multi-zone model based on the Kepler stellar evolution code. All relevant reaction rates on neutron-deficient isotopes up to mass 106 were individually varied by a factor of 100 up and down. Calculations of the 84 changes in reaction rate with the highest impact were then repeated in the 1D multi-zone model. We find a number of uncertain reaction rates that affect predictions of light curves and burst ashes significantly. The results provide insights into the nuclear processes that shape observables from X-ray bursts, and guidance for future nuclear physics work to reduce nuclear uncertainties in X-ray burst models.

Department of Nuclear Reaction - Overview

International Nuclear Information System (INIS)

Budzanowski, A.

2000-01-01

Full text: This year 1999 can be considered as very successful. Not only that we have published 33 papers in journals listed by the Philadelphia Institute of Science but because our hard work allowed us to obtain new and exciting results. A group of theoretical papers concerned with application of correlation among random matrices elements developed for statistical aspects of nuclear coupling into continuum to study of the collective effects in brain activity and stock market dynamics. These papers arose quite an interest and got several citations. Studies of the nonpartonic components in the nucleon structure function led to better understanding of the higher-twist effects. It was shown that inclusion of the terms of the order of 1/Q 4 improves fits to the experimental data. A review paper summarizing results on the role of the leading baryon in high energy reactions appeared in Progress on Nuclear and Particle Physics. Studies on multistep transfer reactions of light heavy ions in collaboration with the Institute of Nuclear Physics of the Ukrainian Academy of Sciences in Kiev have explained angular distributions of many reactions using the coupled channel theory. We have shown that it is possible to determine energy dependence of the optical model potential for such unstable nuclei like 8 Be. Further studies of mechanism of near threshold light meson production in collaboration with Juelich and Jagiellonian University were performed. Within COSY 10 and COSY 11 collaborations new data on the isospin symmetry breaking in pionic reactions and strange meson accompanied by hyperons emission were obtained. Together with colleagues from the Flerov Nuclear Reaction Laboratory we have started experiments with radioactive beams. Using magnetic separator COMBAS velocity distributions of isotopes with 2 ≤Z≤11 in reactions induced by 16 O on 9 Be were obtained. At the high resolution radioactive beam channel ACCULINA reactions induced by 6 He and 8 He nuclei were studied

The semiclassical S-matrix theory of three body Coulomb break-up

International Nuclear Information System (INIS)

Chocian, P.

1999-01-01

Using semiclassical methods we investigate the threshold behaviour for 3-particle break-up of a system with one particle of charge Z and two other particles of charge -q. For the particular case where the ratio of the charges of the third particle to the wing particles is Z/q = 1/4, the Wannier exponent for break-up diverges and it is found that the threshold law changes from a power law to an exponential law of the form exp(-λ/√E) which is in agreement with other results. Wannier's threshold theory is extended analytically to above threshold energies and it is found that the classical law for the divergent case is identical to an analytical result from the quantal hidden crossing theory. Corrections to the threshold behaviour for hydrogen from the above-threshold derivation are compared with those predicted by a calculation from hidden crossing theory. Excellent agreement is found which confirms the success of our classical derivation. The threshold behaviour is tested using semiclassical S-matrix theory above the region of divergence and it is found that for Z/q - of the initial states in S-matrix theory translates to a uniform distribution of outgoing trajectories on the boundary of the reaction zone. Observations of classical trajectories suggest that the radius of the reaction zone (R b ) is dependent on the total energy of the system. R b is determined numerically from ionization trajectories. When the dependence on R b is included in half-collision calculations, cross sections are produced which are in excellent agreement with full-collision S-matrix results for all values of Z > 0.25. (author)

Peaking cladding temperature and break equivalent size of intermediate break loss of coolant accident

International Nuclear Information System (INIS)

Luo Bangqi

2012-01-01

The analysis results of intermediate break loss of coolant accident for the nuclear power plant of million kw level showed to be as following: (1) At the begin of life, the break occur simultaneity reactor shutdown with L(X)P. it's equivalent break size and peaking cladding temperature is respectively 20 cm and 849℃. (2) At the begin of life, the break occur simultaneity reactor shutdown without loop. the reactor coolant pumps will be stop after reactor shutdown 10 minutes, it's equivalent break size and peaking cladding temperature is respectively 10.5 cm and 921℃. (3) At the bur up of 31 GWd/t(EOC1). the break occur simultaneity reactor shutdown without loop, the reactor coolant pumps will be stop after reactor shutdown 20 minutes, it's equivalent break size and peaking cladding temperature is respectively 8 cm and 1145℃. The above analysis results showed that the peaking cladding temperature of intermediate break loss of coolant accident is not only related with the break equivalent size and core bur up, and is closely related with the stop time of coolant pumps because the coolant pumps would drive the coolant from safety system to produce the seal loop in break loop and affect the core coolant flow, results in the fuel cladding temperature increasing or damaging. Therefore, the break spectrum, burn up spectrum, the stop time of coolant pumps and operator action time will need to detail analysis and provide appropriate operating procedure, otherwise the peaking cladding temperature will exceed 1204℃ and threaten the safety of the reactor core when the intermediate break loss of coolant accident occur in some break equivalent size, burn up, stop pumps time and operator action not appropriate. The pressurizer pressure low signal simultaneity containment pressure higher signal were used as the operator manual close the signal of reactor coolant pumps after reactor shutdown of 20 minutes. have successful solved the operator intervention time from 10 minutes

Activation cross-sections of deuteron induced nuclear reactions on neodymium up to 50 MeV

International Nuclear Information System (INIS)

Tárkányi, F.; Takács, S.; Ditrói, F.; Hermanne, A.; Yamazaki, H.; Baba, M.; Mohammadi, A.; Ignatyuk, A.V.

2014-01-01

Highlights: • Experimental excitation function of deuteron induced reactions on natural Nd. • Model code calculations with EMPIRE-D, ALICE-D and TALYS (TENDL-2012). • Physical yield calculation and comparison. • Discussion of medical and industrial applications. - Abstract: In the frame of a systematic study of activation cross sections of deuteron induced nuclear reactions on rare earths, the reactions on neodymium for production of therapeutic radionuclides were measured for the first time. The excitation functions of the nat Nd(d,x) 151,150,149,148m,148g,146,144,143 Pm, 149,147,139m Nd, 142 Pr and 139g Ce nuclear reactions were assessed by using the stacked foil activation technique and high resolution γ-spectrometry. The experimental excitation functions were compared to the theoretical predictions calculated with the modified model codes ALICE-IPPE-D and EMPIRE-II-D and with the data in the TENDL-2012 library based on latest version of the TALYS code. The application of the data in the field of medical isotope production and nuclear reaction theory is discussed

Nuclear Reaction Data File for Astrophysics (NRDF/A) in Hokkaido University Nuclear Reaction Data Center

International Nuclear Information System (INIS)

Kato, Kiyoshi; Kimura, Masaaki; Furutachi, Naoya; Makinaga, Ayano; Togashi, Tomoaki; Otuka, Naohiko

2010-01-01

The activities of the Japan Nuclear Reaction Data Centre is explained. The main task of the centre is data compilation of Japanese nuclear reaction data in collaboration of the International Network of Nuclear Reaction Data Centres. As one of recent activities, preparation of a new database (NRDF/A) and evaluation of astronuclear reaction data are reported. Collaboration in the nuclear data activities among Asian countries is proposed.

Atomic nuclei and nuclear reactions. Theory and application

International Nuclear Information System (INIS)

Sitenko, A.G.; Tartakovsky, V.K.; Kenjebaev, K.K.; Shunkeyev, K.Sh.; Ismatov, E.I.; Mukhammedov, S.; Comsan, M.N.H.; Djuraev, Sh.Kh.

2004-01-01

Full text: The short description of the book preparation by the collective authors from Ukraine, Kazakhstan, Uzbekistan and Egypt is given. The present book is the expanded course of lectures on the theory of nuclei, nuclear reactions and their applications delivered by the authors for a number of years in the Ukrainian National University, Aktubinsk State University of the Kazakhstan Republic, Tashkent National University, Samarkand and Termez State Universities of Uzbekistan Republic, Egyptian National Universities (Al-Az'har, Menoufeya, Suez-Canal and Tanta) and the Institute of Nuclear Physics of the Academy of Sciences of the Republic of Uzbekistan. The lectures present foundations of the modern concepts of the structure of nuclei, on the nature of nuclear processes and nuclear transformations. Main attention in the book was paid to the presentation of the basics and some modern achievements in the field of the theory of nuclei and nuclear reactions. A number of problems was investigated in original works and were not presented in the physics textbooks. The book presents the non-relativistic theory of nuclear reactions, questions of relativistic nuclear physics were not considered here. Non-relativistic theory of nuclear reactions is based on the notions of collision matrix or S-matrix. In absence of consequent microscopic theory, the scattering matrix can be found phenomenological based on definite assumptions on the character of nuclear interactions. Modern applications of nuclear reactions for the development of nuclear methods of analysis are presented. The delayed and nuclear techniques with nuclear reactor, accelerators and radioisotopic sources are considered. The book is designed as a textbook for bachelor and postgraduate students of physical faculties of universities and engineering-physical institutions, lecturers and researchers, working in the field of nuclear physics. The book gives an up-to-date list of references on nuclear reaction theory and

Dispersion Theory of Direct Nuclear Reactions

Energy Technology Data Exchange (ETDEWEB)

Shapiro, I. S. [Institute Of Theoretical And Experimental Physics, Moscow, USSR (Russian Federation)

1963-01-15

reasons for the agreement if it is not accidental. In short, the theory behaves like an unpredictable person. A major success in the application of perturbation theory to direct processes in the Butler theory of deuteron stripping ((d, p), (d, n)) and pick-up ((p, d), (n, d)). The Butler theory satisfactorily predicts the position of the first maximum (by the increase of the angle) in the angular distribution of reaction products as a function of the orbital momentum of the nucleon captured by the nucleus (stripping reaction) or picked up by an incident particle (pick- up reaction). This result permitted the use of stripping and pick-up reactions in nuclear spectroscopy. At the same time this led to the problem of understanding the true meaning of the Butler approximation. This problem was also essential because the Butler theory inadequately describes several other features of the stripping and pick-up reactions (such as the change of angular distribution with the energy of incident particles, the relation of intensities at the maxima of angular distributions, absolute values of. cross-sections and, sometimes, the relative probabilities for the excitation of different states of residual nuclei). A new method in direct process theory was offered not so long ago (in 1961). The method is based on fairly general properties of the reaction amplitudes and is free from the un-justified assumptions, of the form er theory, in particular the application of perturbation theory. This method makes it possible to obtain several new results and obtain a uniform description cf a great variety of processes (such as direct reactions of the conventional type at low and medium energies, the transfer of nucleons in the bombardment of nuclei by multi-charged ions and the processes of fragmentation at high energies). At the same time the new approach explains, with surprising simplicity, the causes of the form erly enigmatic success of the Butler theory and indicates the limits of its

Dispersion Theory of Direct Nuclear Reactions

International Nuclear Information System (INIS)

Shapiro, I.S.

1963-01-01

reasons for the agreement if it is not accidental. In short, the theory behaves like an unpredictable person. A major success in the application of perturbation theory to direct processes in the Butler theory of deuteron stripping ((d, p), (d, n)) and pick-up ((p, d), (n, d)). The Butler theory satisfactorily predicts the position of the first maximum (by the increase of the angle) in the angular distribution of reaction products as a function of the orbital momentum of the nucleon captured by the nucleus (stripping reaction) or picked up by an incident particle (pick- up reaction). This result permitted the use of stripping and pick-up reactions in nuclear spectroscopy. At the same time this led to the problem of understanding the true meaning of the Butler approximation. This problem was also essential because the Butler theory inadequately describes several other features of the stripping and pick-up reactions (such as the change of angular distribution with the energy of incident particles, the relation of intensities at the maxima of angular distributions, absolute values of. cross-sections and, sometimes, the relative probabilities for the excitation of different states of residual nuclei). A new method in direct process theory was offered not so long ago (in 1961). The method is based on fairly general properties of the reaction amplitudes and is free from the un-justified assumptions, of the form er theory, in particular the application of perturbation theory. This method makes it possible to obtain several new results and obtain a uniform description cf a great variety of processes (such as direct reactions of the conventional type at low and medium energies, the transfer of nucleons in the bombardment of nuclei by multi-charged ions and the processes of fragmentation at high energies). At the same time the new approach explains, with surprising simplicity, the causes of the form erly enigmatic success of the Butler theory and indicates the limits of its

Nuclear Reaction Data Centers

International Nuclear Information System (INIS)

McLane, V.; Nordborg, C.; Lemmel, H.D.; Manokhin, V.N.

1988-01-01

The cooperating Nuclear Reaction Data Centers are involved in the compilation and exchange of nuclear reaction data for incident neutrons, charged particles and photons. Individual centers may also have services in other areas, e.g., evaluated data, nuclear structure and decay data, reactor physics, nuclear safety; some of this information may also be exchanged between interested centers. 20 refs., 1 tab

Nuclear reaction data and nuclear reactors

Energy Technology Data Exchange (ETDEWEB)

Paver, N [University of Trieste (Italy); Herman, M [International Atomic Energy Agency, Vienna (Austria); Gandini, A [ENEA, Rome (Italy)

2001-12-15

These two volumes contain the lecture notes of the workshop 'Nuclear Reaction Data and Nuclear Reactors: Physics, Design and Safety', which was held at the Abdus Salam ICTP in the Spring of 2000. The workshop consisted of five weeks of lecture courses followed by practical computer exercises on nuclear data treatment and design of nuclear power systems. The spectrum of topics is wide enough to timely cover the state-of-the-art and the perspectives of this broad field. The first two weeks were devoted to nuclear reaction models and nuclear data evaluation. Nuclear data processing for applications to reactor calculations was the subject of the third week. On the last two weeks reactor physics and on-going projects in nuclear power generation, waste disposal and safety were presented.

Stability of Monetary Unions : Lessons from the Break-Up of Czechoslovakia

NARCIS (Netherlands)

Fidrmuc, J.; Horváth, J.

1998-01-01

In 1993, Czechoslovakia experienced a two-fold break-up: On January 1st, the country disintegrated as a political union, while preserving an economic and monetary union. Then, the Czech-Slovak monetary union collapsed on February 8th. We analyze the economic background of the two break-ups, and

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

Science.gov (United States)

Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

2017-05-01

Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

Leak-before-break behaviour of nuclear piping systems

International Nuclear Information System (INIS)

Bartholome, G.; Wellein, R.

1992-01-01

The general concept for break preclusion of nuclear piping systems in the FRG consists of two main prerequisites: Basic safety; independent redundancies. The leak-before-break behaviour is open of these redundancies and will be verified by fracture mechanics. The following items have to be evaluated: The growth of detected and postulated defects must be negligible in one life time of the plant; the growth behaviour beyond design (i.e. multiple load collectives are taken into account) leads to a stable leak; This leakage of the piping must be detected by an adequate leak detection system long before the critical defect size is reached. The fracture mechanics calculations concerning growth and instability of the relevant defects and corresponding leakage areas are described in more detail. The leak-before-break behaviour is shown for two examples of nuclear piping systems in pressurized water reactors: main coolant line of SIEMENS-PWR 1300 MW (ferritic material, diameter 800 mm); surge line of Russian WWER 440 (austenitic material, diameter 250 mm). The main results are given taking into account the relevant leak detection possibilities. (author). 9 refs, 9 figs

Development of technique for estimating primary cooling system break diameter in predicting nuclear emergency event sequence

International Nuclear Information System (INIS)

Tatebe, Yasumasa; Yoshida, Yoshitaka

2012-01-01

If an emergency event occurs in a nuclear power plant, appropriate action is selected and taken in accordance with the plant status, which changes from time to time, in order to prevent escalation and mitigate the event consequences. It is thus important to predict the event sequence and identify the plant behavior resulting from the action taken. In predicting the event sequence during a loss-of-coolant accident (LOCA), it is necessary to estimate break diameter. The conventional method for this estimation is time-consuming, since it involves multiple sensitivity analyses to determine the break diameter that is consistent with the plant behavior. To speed up the process of predicting the nuclear emergency event sequence, a new break diameter estimation technique that is applicable to pressurized water reactors was developed in this study. This technique enables the estimation of break diameter using the plant data sent from the safety parameter display system (SPDS), with focus on the depressurization rate in the reactor cooling system (RCS) during LOCA. The results of LOCA analysis, performed by varying the break diameter using the MAAP4 and RELAP5/MOD3.2 codes, confirmed that the RCS depressurization rate could be expressed by the log linear function of break diameter, except in the case of a small leak, in which RCS depressurization is affected by the coolant charging system and the high-pressure injection system. A correlation equation for break diameter estimation was developed from this function and tested for accuracy. Testing verified that the correlation equation could estimate break diameter accurately within an error of approximately 16%, even if the leak increases gradually, changing the plant status. (author)

Parental break-ups and stress: roles of age & family structure in 44 509 pre-adolescent children.

Science.gov (United States)

Dissing, Agnete S; Dich, Nadya; Andersen, Anne-Marie Nybo; Lund, Rikke; Rod, Naja H

2017-10-01

Parental break-up is wide spread, and the effects of parental break-up on children's well-being are known. The evidence regarding child age at break-up and subsequent family arrangements is inconclusive. Aim: to estimate the effects of parental break-up on stress in pre-adolescent children with a specific focus on age at break-up and post-breakup family arrangements. We used data from the Danish National Birth Cohort. Participants included 44 509 children followed from birth to age 11. Stress was self-reported by children at age 11, when the children also reported on parental break-up and post break-up family arrangements. Twenty-one percent of the children had experienced a parental break-up at age 11, and those who had experienced parental break-up showed a higher risk of stress (OR:1.72, 95%CI:1.55;1.91) regardless of the child's age at break-up. Children living in a new family with stepparents (OR = 1.63, 95%CI:1.38;1.92), or shared between the parents (OR = 1.48, 95%CI:1.26;1.75) reported higher stress than children of intact families. Single parent families reported markedly higher stress levels than children in intact families (OR = 2.18, 95%CI:1.90;2.50) and all other family types. Children who were satisfied with their living arrangements post-break-up reported the same stress level as children living in intact families (OR = 1.01, 95%CI:0.86;1.18). Children who experience parental break-up have higher stress levels, also many years after the break-up, and those living in a single parent household post break-up seem to be most vulnerable. Living arrangements post-breakup should be further investigated as a potential protective factor. © The Author 2017. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Nuclear reactions as structure probes

International Nuclear Information System (INIS)

Fernandez, Bernard; Cugnon, Joseph; Roussel-Chomaz, Patricia; Sparenberg, Jean-Marc; Oliveira Santos, Francois de; Bauge, Eric; Poves, Alfredo; Keeley, Nicholas; Simenel, Cedric; Avez, Benoit; Lacroix, Denis; Baye, Daniel; Cortina-Gil, Dolores; Pons, Alexandre

2007-09-01

This publication gathers courses which aim at giving a view on new experiments which are performed by using radioactive beams, notably low intensity beams, in different accelerators, and allow the structure of very exotic nuclei to be characterized. Experimental as well as theoretical aspects are thus addressed. The contributions propose: a brief history of nuclear reactions and of instruments used to study them from the discovery of nucleus to the DWBA (Distorted Wave Born Approximation); an overview of nuclear reactions; experimental techniques; the theory of collisions at low energy; resonant elastic scattering, inelastic scattering and astrophysical reactions; to probe nuclear structure with nucleons; shell model and spectroscopic factors; analysis of transfer reactions and determination of spectroscopic factors; microscopic approaches of nuclear dynamics; theoretical aspects of dissociation reactions; experimental aspects of knockout reactions; research in oenology with the chemical characterisation of defective ageing of dry white wines

Dynamics and Thermodynamics with Nuclear Degrees of Freedom

CERN Document Server

Chomaz, Philippe; Trautmann, Wolfgang; Yennello, Sherry J

2006-01-01

The study of nuclear reaction dynamics and thermodynamics with nuclear degrees of freedom has progressed dramatically in the past 20 years, from inclusive charge distributions to exclusive isotopically resolved fragment observables and from schematic phenomenological break-up models to sophisticated quantum many-body transport theories. A coherent and quantitative understanding of reaction mechanisms and of the underlying nuclear matter equation of state is emerging from the analysis of experimental data and from the theoretical modeling of heavy ion reactions. In addition, the accumulated evidence for phenomena related to the liquid-gas phase transition of nuclear matter has triggered interdisciplinary activities and the transfer of useful methods. In the near future, the availability of radioactive beam facilities is expected to provide unique opportunities for extending our knowledge of the dynamic properties and the nuclear phase diagram towards exotic nuclear systems with important astrophysical implicat...

Nuclear reactions in astrophysics

International Nuclear Information System (INIS)

Arnould, M.; Rayet, M.

1990-01-01

At all times and at all astrophysical scales, nuclear reactions have played and continue to play a key role. This concerns the energetics as well as the production of nuclides (nucleosynthesis). After a brief review of the observed composition of various objects in the universe, and especially of the solar system, the basic ingredients that are required in order to build up models for the chemical evolution of galaxies are sketched. Special attention is paid to the evaluation of the stellar yields through an overview of the important burning episodes and nucleosynthetic processes that can develop in non-exploding or exploding stars. Emphasis is put on the remaining astrophysical and nuclear physics uncertainties that hamper a clear understanding of the observed characteristics, and especially compositions, of a large variety of astrophysical objects

Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52 MeV

OpenAIRE

Ditrói, F.; Takács, S.; Haba, H.; Komori, Y.; Aikawa, M.

2016-01-01

Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2 MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. Th...

Transfer of 6Li break-up fragments at 6Li projectile energies far above the coulomb barrier

International Nuclear Information System (INIS)

Neumann, B.; Buschmann, J.; Rebel, H.; Gils, H.J.; Klewe-Nebenius, H.

1979-05-01

Transfer of beam-velocity fragments has been experimentally investigated in 6 Li induced reactions on 208 Pb and 209 Bi in the energy range Esub(Li) = 60-156 MeV. The experimental techniques involve the observation of the target residues and measurements of the recoil ranges of heavy residual nuclei produced by charged particle bombardment. The determination of the recoil energy enables the discrimination of different reaction paths leading to the same residual nuclei. ( 6 Li, xn+p) excitation functions prove to be very similar to (α,(x-1)n) reactions at Esub(α) approximately 2/3 x Esub(Li). The results present experimental evidence for a particular reaction type indicated in previous experiments: Dissociation of the 6 Li projectile with capture of the beam-velocity alpha particle indicating an (α,xn) reaction ('internal break-up'). (orig.) [de

The break-up of a viscous liquid drop in a high Reynolds number shear flow

Science.gov (United States)

Ng, Chin Hei; Aliseda, Alberto

2015-11-01

The break-up of a viscous liquid droplet in a sheared turbulent flow evolves in several steps, the most visually dominant of which is the formation of high aspect ratio ligaments. This feature takes them apart from the various break-up models based on the Hinze-Kolmogorov paradigm of eddy-spherical particle collisions. We investigate the development of ligaments in a high Reynolds number (up to 250,000) submerged round jet, within the high viscosity, near-unity density ratio regime. Unlike in H-K theory, applicable to the break-up of inviscid fluid particles, break-up of inertial-scale viscous droplets occurs through a sequence of eddy collisions and long-term deformation, as evidenced by measurements of the aspect ratio that fluctuates and increases progressively during the deformation stage, and results in non-binary break-up. Additionally, the ligament formation stretches a droplet to multiple times its original size, bringing the influence of integral-scale structures. High speed imaging has been statistically analyzed to inform and validate theoretical models for the break-up time and the break-up probability. In addition, a particle size scaling model has been developed and compared with the experimental measurements of the frozen-state particle size.

The unified theory of nuclear reactions

International Nuclear Information System (INIS)

Tobocman, W.

A unified nuclear reaction theory is a formalism for the scattering reactions of many-body nuclear systems which is capable of describing both direct interaction and compound nucleus formation processes. The Feshbach projection operator formalism is the original unified nuclear reaction theory. An alternative unified nuclear reaction theory called the X-matrix formalism is described. The X-matrix formalism is a generalization of the Brown-de Dominicis formalism. It does not require projection operators and is readly applied to rearrangement collisions

Outline of cold nuclear fusion reaction

International Nuclear Information System (INIS)

Tachikawa, Enzo

1991-01-01

In 2010, as the total supply capacity of primary energy, 666 million liter is anticipated under the measures of thorough energy conservation. The development of energy sources along the energy policy based on environment preservation, safety, the quantity of resources and economy is strongly demanded. The nuclear power generation utilizing nuclear fission has been successfully carried out. As the third means of energy production, the basic research and technical development have been actively advanced on the energy production utilizing nuclear fusion reaction. The main object of the nuclear fusion research being advanced now is D-D reaction and D-T reaction. In order to realize low temperature nuclear fusion reaction, muon nuclear fusion has been studied so far. The cold nuclear fusion reaction by the electrolysis of heavy water has been reported in 1989, and its outline is ixplained in this report. The trend of the research on cold nuclear fusion is described. But the possibility of cold nuclear fusion as an energy source is almost denied. (K.I.)

Excitation functions of deuteron induced nuclear reactions on natMo up to 21 MeV. An alternative route for the production of 99mTc and 99Mo

International Nuclear Information System (INIS)

Sonck, M.; Hermanne, A.; Takacs, S.; Szelecsenyi, F.; Tarkanyi, F.

1999-01-01

Cross sections of deuteron induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions of 92m,95 Nb-, 93,94g,94m,95g,95m,96,99m Tc- and 99 Mo were measured up to 21 MeV deuteron energy by using stacked foil technique and activation method. The goal of this work was to study the production possibility of the medical important 94m,99m Tc- and 99 Mo-nuclides. Production of 99m Tc and 99 Mo is of importance for their use in nuclear medicine, whereas 94m Tc is of interest regarding quantification of kinetics of well-established 99m Tc-radiopharmaceuticals. The production possibilities of 99m Tc and 99 Mo above 20 MeV deuteron energies up to 50 MeV were estimated and was found that beside the proton induced reactions the deuteron induced reactions on enriched molybdenum target are very promising. (author)

Investigations of direct and sequential Coulomb break-up of light ions

International Nuclear Information System (INIS)

Srivastava, D.K.; Basu, D.N.; Rebel, H.

1988-07-01

Coulomb dissociation of 6 Li in the field of 208 Pb at different energies via resonance and continuum levels is discussed in detail. Relations are given which can be used to directly relate the Coulomb break-up cross section to the astrophysical S-factor. Predictions for energy dependence and angular-distributions are given. The direct Coulomb break-up of 6 Li is found to be of the same order of magnitude as the sequential break-up at higher projectile energies. The effect to eleastic scattering can be accounted for by introducing a dynamic polarization potential. Predictions are given for the direct Coulomb dissociation of 26 MeV/nucleon 7 Li and 16 O incident on 208 Pb through dipole transitions to the continuum, and for 20 Ne via quadrupole transitions in similar experimental situations. (orig.) [de

Importance of d-wave contributions in the charge symmetry breaking reaction dd →4Heπ0

Science.gov (United States)

Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Czerwiński, E.; Demmich, K.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Hanhart, C.; Heijkenskjöld, L.; Hejny, V.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khatri, G.; Khoukaz, A.; Khreptak, O.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Parol, W.; Perez del Rio, E.; Piskunov, N. M.; Prasuhn, D.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Rundel, O.; Sawant, S.; Schadmand, S.; Schätti-Ozerianska, I.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Sitterberg, K.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Trzciński, A.; Wolke, M.; Wrońska, A.; Wüstner, P.; Yamamoto, A.; Zabierowski, J.; Zieliński, M. J.; Złomańczuk, J.; Żuprański, P.; Żurek, M.; WASA-at-COSY Collaboration

2018-06-01

This letter reports a first quantitative analysis of the contribution of higher partial waves in the charge symmetry breaking reaction dd →4Heπ0 using the WASA-at-COSY detector setup at an excess energy of Q = 60MeV. The determined differential cross section can be parametrized as d σ /d Ω = a + bcos2 ⁡θ*, where θ* is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a = (1.55 ± 0.46(stat) + 0.32 - 0.8 (syst)) pb /sr and b = (13.1 ± 2.1 (stat)-2.7+1.0 (syst)) pb /sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the Δ isobar to the dd →4Heπ0 reaction and is, therefore, crucial for a quantitative understanding of quark mass effects in nuclear production reactions.

Extension of activation cross section data of long lived products in deuteron induced nuclear reactions on platinum up to 50 MeV

Energy Technology Data Exchange (ETDEWEB)

Ditrói, F., E-mail: ditroi@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen (Hungary); Tárkányi, F.; Takács, S. [Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen (Hungary); Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel, Brussels (Belgium)

2017-06-15

Highlights: • Deuteron induced nuclear reactions on natural platinum up to 50 MeV. • Stacked foil irradiation technique. • Comparison with the TENDL-2014 and TENDL-2015 calculations. • Cross section of Au, Pt and Ir radioisotopes. • Application for Thin Layer Activation (TLA). - Abstract: In the frame of a systematical study of light ion induced nuclear reactions on platinum, activation cross sections for deuteron induced reactions were investigated. Excitation functions were measured in the 20.8–49.2 MeV energy range for the {sup nat}Pt(d,xn){sup 191,192,193,194,195,196m2,196g,198g,199}Au, {sup nat}Pt(d,x){sup 188,189,191,195m,197m,197g}Pt and {sup nat}Pt(d,x){sup 189,190,192,194m2}Ir reactions by using the stacked foil irradiation technique. The experimental results are compared with previous results from the literature and with the theoretical predictions in the TENDL-2014 and TENDL-2015 libraries. The applicability of the produced radio-tracers for wear measurements has been presented.

The nuclear reaction model code MEDICUS

International Nuclear Information System (INIS)

Ibishia, A.I.

2008-01-01

The new computer code MEDICUS has been used to calculate cross sections of nuclear reactions. The code, implemented in MATLAB 6.5, Mathematica 5, and Fortran 95 programming languages, can be run in graphical and command line mode. Graphical User Interface (GUI) has been built that allows the user to perform calculations and to plot results just by mouse clicking. The MS Windows XP and Red Hat Linux platforms are supported. MEDICUS is a modern nuclear reaction code that can compute charged particle-, photon-, and neutron-induced reactions in the energy range from thresholds to about 200 MeV. The calculation of the cross sections of nuclear reactions are done in the framework of the Exact Many-Body Nuclear Cluster Model (EMBNCM), Direct Nuclear Reactions, Pre-equilibrium Reactions, Optical Model, DWBA, and Exciton Model with Cluster Emission. The code can be used also for the calculation of nuclear cluster structure of nuclei. We have calculated nuclear cluster models for some nuclei such as 177 Lu, 90 Y, and 27 Al. It has been found that nucleus 27 Al can be represented through the two different nuclear cluster models: 25 Mg + d and 24 Na + 3 He. Cross sections in function of energy for the reaction 27 Al( 3 He,x) 22 Na, established as a production method of 22 Na, are calculated by the code MEDICUS. Theoretical calculations of cross sections are in good agreement with experimental results. Reaction mechanisms are taken into account. (author)

Low energy nuclear reactions: 2007 update

International Nuclear Information System (INIS)

Krivit, S. B.

2007-01-01

demonstrated the most remarkable evidence of nuclear reactions in the 18-year history of this field: evidence of charged particles in unprecedented magnitudes. A brief overview of their work is provided. The published theory proposed by Allan Widom and Lewis Larsen will be briefly reviewed. No technical faults with the theory have been reported to date. The theory may be able to explain what have been described as the three miracles of 'cold fusion': the lack of strong neutron emissions; the mystery of how the Coulomb barrier is penetrated; and the lack of strong emission of gamma or x-rays. Sociological and Political Trends Public and scientific perception of LENR over the last 18 years has strongly affected progress in the field. This influence will be considered, as will the sociological and political impact of potentially paradigm-breaking science research and exploration in general

Inclusive measurements of the break-up of 156 MeV 6Li-ions at extreme forward angles and the quasi free break-up model

International Nuclear Information System (INIS)

Jellito, H.; Buschmann, J.; Gils, H.J.; Heide, N.; Kiener, J.; Rebel, H.; Zagromski, S.; Samanta, C.

1988-11-01

Inclusive alpha particle and deuteron spectra from collisions of 156 MeV 6 Li-ions with 12 C and 208 Pb were measured at extreme forward emission angles including zero degree. The measurements were performed with the Karlsruhe magnetic spectrograph 'Little John' and required an efficient reduction of the background from small-angle scattering. The observed double differential cross sections and angular distributions have been analysed on the basis of Serber's spectator break-up model. When going to angles smaller than grazing, where Coulomb effects are expected to the dominating, transitional features may appear. Corresponding effects probably associated with Coulomb break-up are observed with the 208 Pb-target and require a slight extension of the Serber approach. In the case of the 12 C-target the break-up cross sections in forward direction seem to reflect the shape of the internal momentum distribution of the alpha particle and deuteron cluster in the 6 Li-projectile and are in agreement with a 2S-type wave function. However, at larger angles the shape appears to be distorted, possibly by final state interactions. (orig.) [de

Development of the system for excitation function automatic measurement of nuclear reactions

International Nuclear Information System (INIS)

Sapozhnikov, A.B.

2004-01-01

Full text: The resonance nuclear reaction method is applied at the tandem accelerator UKP-2-1 to determinate films thickness and obtain light element depth distribution. The system for automatic measurement of the nuclear reaction excitation curve has been developed. It allowed to obtain an excitation function of nuclear reaction using continuous changing potential of the target with energy step of 6 eV. Saw-tooth voltage with amplitude up to 6 kV from the block of scanning beam is fed to a target. The amplitude is determined by constant voltage from the scanning beam block control. Nal(Tl) detector detects gamma quanta - the products of a nuclear reaction and transforms they in voltage impulses. The impulses through the amplifier income in the single-channel analyzer which forms impulses to start the analog-to-digital converter. The value of saw-tooth voltage corresponding to the moment of gamma quantum detection is read by the analog-to-digital converter, where it is transformed to digital code and transmitted to the computer. The computer program has been developed to control the process of accumulation of excitation function. The dependence a detected γ-quanta yield from a target potential is automatically plotted by the program. This dependence corresponds to the nuclear reaction excitation function. If scanning amplitude is not enough in order to scan need depth of a sample, an operator increases energy of the proton beam changing high voltage potential of the terminal up 3 keV and measures the nuclear reaction excitation function with the new energy. This procedure can be repeated some times. After that 'sewing' of excitation functions is carried out by the program under the hypothesis that nuclear reaction yield in last points be identical

Statistical theory of precompound nuclear reactions

International Nuclear Information System (INIS)

Nishioka, H.

1986-01-01

The purpose of the paper is to show the application of the Grassmann-integration method (or the graded-symmetry method) to a pre-equilibrium process in nuclear reactions. The Grassmann-integration method for random systems was first introduced by Efetov and later largely extended and applied to nuclear physics by Verbaarschot, Weidenmuller and Zirnbauer (referred to as VWZ). They have applied it to the equilibrium nuclear reactions; namely; the compound-nucleus reactions. It will be shown in this paper that this method is also applicable to non-equilibrium nuclear reactions. Applying this method to precompound nuclear reactions, the authors have obtained the same expression of the cross-section as Agassi, Weidenmuller and Mantzouranis (referred to as AWM) in the weak-coupling limit. In the general case their results show an important modification to AWM

Trojan horse particle invariance: The impact on nuclear astrophysics

International Nuclear Information System (INIS)

Pizzone, R. G.; La Cognata, M.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L. D.; Lamia, L.; Spartá, R.; Tumino, A.

2014-01-01

In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previous studies will be extended to the cases of the binary d(d, p)t and 6 Li(d,α) 4 He reactions, which were tested using different quasi-free break-up's, namely 6 Li and 3 He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions

Trojan horse particle invariance: The impact on nuclear astrophysics

Energy Technology Data Exchange (ETDEWEB)

Pizzone, R. G.; La Cognata, M. [Laboratori Nazionali del Sud - INFN, Catania (Italy); Spitaleri, C. [Universitá di Catania and Laboratori Nazionali del Sud - INFN (Italy); Bertulani, C. A. [Texas A and M University, Commerce (United States); Mukhamedzhanov, A. M. [Texas A and M University, College Station, Texas (United States); Blokhintsev, L. D. [Moscow State University, Moscow (Russian Federation); Lamia, L.; Spartá, R. [Universitá di Catania and Laboratori Nazionali del Sud - INFN, Catania (Italy); Tumino, A. [Universitá Kore, Enna (Italy)

2014-05-02

In the current picture of nuclear astrophysics indirect methods and, in particular, the Trojan Horse Method cover a crucial role for the measurement of charged particle induced reactions cross sections of astrophysical interest, in the energy range required by the astrophysical scenarios. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The key to the method is the quasi-free break-up and some of its properties will be investigated in the present work. In particular, the Trojan Horse nucleus invariance will be studied and previous studies will be extended to the cases of the binary d(d, p)t and {sup 6}Li(d,α){sup 4}He reactions, which were tested using different quasi-free break-up's, namely {sup 6}Li and {sup 3}He. The astrophysical S(E)-factor were then extracted with the Trojan Horse formalism applied to the two different break-up schemes and compared with direct data as well as with previous indirect investigations. The very good agreement confirms the independence of binary indirect cross section on the chosen spectator particle also for these reactions.

Nuclear reactions with radioactive and stable beams (Part I)

International Nuclear Information System (INIS)

Aguilera R, E.F.; Martinez Q, E.; Gomez C, A.

2004-12-01

At the present time there is a great interest at world level in experiments, with accelerated nuclei of short half life. The dispersion, fusion, transfer and break processes in the interaction of weakly light projectiles bounded with targets of Z great its have been object of intense recent investigation, at world level. Our group, in collaboration with the University of Notre Dame, it has measured and analyzed these processes for weakly bound systems as: 6 He + 209 Bi, 8 Li + 208 Pb, 10 Be + 208 Pb. On the other hand a research line that has wakened up great interest, it is that of studies of resonant reactions using the Inverse Kinematics technique with thick targets. The use of this technique allows to measure an entire excitation function with a single bombardment. Our group has carried out, in the ININ, preliminary bombardments for the system 12 C + 4 He. This allowed to establish the feasibility of implementing this technique in our Laboratory. The application of this and other techniques to different systems like 18 O + 4 He, 12 C + 12 C, 12 C + 16 O, 16 O + 16 O, it opens the possibility to measure the fusion of these systems at very low energy and to deepen in the knowledge of the nuclear structure and the nuclear astrophysics. In this technical report, the activities carried out by our group during 2004 are described.(Author)

SkyNet: Modular nuclear reaction network library

Science.gov (United States)

Lippuner, Jonas; Roberts, Luke F.

2017-10-01

The general-purpose nuclear reaction network SkyNet evolves the abundances of nuclear species under the influence of nuclear reactions. SkyNet can be used to compute the nucleosynthesis evolution in all astrophysical scenarios where nucleosynthesis occurs. Any list of isotopes can be evolved and SkyNet supports various different types of nuclear reactions. SkyNet is modular, permitting new or existing physics, such as nuclear reactions or equations of state, to be easily added or modified.

The Cascade-Exciton Approach to Nuclear Reactions. (Foundation and Achievements)

International Nuclear Information System (INIS)

Mashnik, S.G.

1994-01-01

The relativistic kinetic equations describing nuclear reactions at intermediate energies are obtained on the dynamical basis. These equations are analyzed and realized in several versions of the Cascade Exciton Model (CEM). The CEM assumes that reactions occur in three stages: the intranuclear cascade, pre-equilibrium and the evaporative ones. A large variety of experimental data on hadron- and photonuclear reactions in the bombarding energy range up to several GeV are analyzed in this approach. The contributions of different pion and photon absorption mechanisms and the relative role of different particle and photon production mechanisms in these reactions are estimated. The CEM describes adequately nuclear reactions at intermediate energies and has one of the best predictive powers as compared to other available modern models. 55 refs., 10 figs., 1 tab

Computational modeling of ice cracking and break-up from helicopter blades

KAUST Repository

Shiping, Zhang; Khurram, Rooh Ul Amin; Fouladi, Habibollah; Habashi, Wagdi G (Ed)

2012-01-01

In order to reduce the danger of impact onto components caused by break-up, it is important to analyze the shape of shed ice accumulated during flight. In this paper, we will present a 3D finite element method (FEM) to predict the shed ice shape by using a fluid-solid interaction (FSI) approach to determine the loads, and linear fracture mechanics to track crack propagation. Typical icing scenarios for helicopters are analyzed, and the possibility of ice break-up is investigated.

Computational modeling of ice cracking and break-up from helicopter blades

KAUST Repository

Shiping, Zhang

2012-06-25

In order to reduce the danger of impact onto components caused by break-up, it is important to analyze the shape of shed ice accumulated during flight. In this paper, we will present a 3D finite element method (FEM) to predict the shed ice shape by using a fluid-solid interaction (FSI) approach to determine the loads, and linear fracture mechanics to track crack propagation. Typical icing scenarios for helicopters are analyzed, and the possibility of ice break-up is investigated.

Low Energy Nuclear Reactions: 2007 Update

Science.gov (United States)

Krivit, Steven B.

2007-03-01

This paper presents an overview of low energy nuclear reactions, a subset of the field of condensed matter nuclear science. Condensed matter nuclear science studies nuclear effects in and/or on condensed matter, including low energy nuclear reactions, an entirely new branch of science that gained widespread attention and notoriety beginning in 1989 with the announcement of a previously unrecognized source of energy by Martin Fleischmann and Stanley Pons that came to be known as cold fusion. Two branches of LENR are recognized. The first includes a set of reactions like those observed by Fleischmann and Pons that use palladium and deuterium and yield excess heat and helium-4. Numerous mechanisms have been proposed to explain these reactions, however there is no consensus for, or general acceptance of, any of the theories. The claim of fusion is still considered speculative and, as such, is not an ideal term for this work. The other branch is a wide assortment of nuclear reactions that may occur with either hydrogen or deuterium. Anomalous nuclear transmutations are reported that involve light as well as heavy elements. The significant questions that face this field of research are: 1) Are LENRs a genuine nuclear reaction? 2) If so, is there a release of excess energy? 3) If there is, is the energy release cost-effective?

Asian collaboration on nuclear reaction data compilation

International Nuclear Information System (INIS)

Aikawa, Masayuki; Furutachi, Naoya; Kato, Kiyoshi; Makinaga, Ayano; Devi, Vidya; Ichinkhorloo, Dagvadorj; Odsuren, Myagmarjav; Tsubakihara, Kohsuke; Katayama, Toshiyuki; Otuka, Naohiko

2013-01-01

Nuclear reaction data are essential for research and development in nuclear engineering, radiation therapy, nuclear physics and astrophysics. Experimental data must be compiled in a database and be accessible to nuclear data users. One of the nuclear reaction databases is the EXFOR database maintained by the International Network of Nuclear Reaction Data Centres (NRDC) under the auspices of the International Atomic Energy Agency. Recently, collaboration among the Asian NRDC members is being further developed under the support of the Asia-Africa Science Platform Program of the Japan Society for the Promotion of Science. We report the activity for three years to develop the Asian collaboration on nuclear reaction data compilation. (author)

Nuclear reactions excited by recoil protons on a nuclear reactor

International Nuclear Information System (INIS)

Mukhammedov, S.; Khaydarov, A.; Barsukova, E.G.

2006-01-01

The nuclear reactions excited by recoil protons and of the detection possibility of the various chemical elements with the use of these secondary nucleus reactions were investigated. The recoil protons are produced on a nuclear reactor in the result of (n, p) inelastic and elastic scattering interaction of fast neutrons with nuclei of hydrogen. It is well known that the share of fast neutrons in energetic spectrum of reactor's neutrons in comparison with the share of thermal neutrons is small. . Consequently, the share of recoil protons produced in the result of fast neutron interaction with nuclei of light elements, capable to cause the nuclear reactions, is also small, des, due to Coulomb barrier of nuclei the recoil protons can cause the nuclear reactions only on nuclei of light and some middle elements. Our studies show that observable yields have radio nuclides excited in the result of nuclear reactions on Li, B, O, V and Cu. Our experimental results have demonstrated that the proton activation analysis based on the application of secondary nuclear reactions is useful technique to determine large contents of various light and medium chemical elements. Detection limits for studied chemical elements are estimated better than 10 ppm

Introduction to nuclear reactions

International Nuclear Information System (INIS)

Satchler, G.R.

1980-01-01

This introduction to nuclear reaction phenomena is aimed primarily but not exclusively at readers at the undergraduate student level. An overview of the subject is presented in the first two chapters entitled - Some background information and Introduction to nuclear reactions. The third chapter reviews scattering theory with emphasis on the underlying physical ideas and also provides schematic entrees to the more advanced topics. The physical models which have been developed to account for the various aspects of nuclear phenomena are described in more detail in chapter 4. References and exercises are appended to each chapter. (U.K.)

COMPLEX SIMULATION MODEL OF TRAIN BREAKING-UP PROCESS AT THE HUMPS

Directory of Open Access Journals (Sweden)

E. B. Demchenko

2015-11-01

Full Text Available Purpose. One of the priorities of station sorting complex functioning improvement is the breaking-up process energy consumptions reduction, namely: fuel consumption for train pushing and electric energy consumption for cut braking. In this regard, an effective solution of the problem of energy consumption reduction at breaking-up subsystem requires a comprehensive handling of train pushing and cut rolling down processes. At the same time, the analysis showed that the current task of pushing process improvement and cut rolling down effectiveness increase are solved separately. To solve this problem it is necessary to develop the complex simulation model of train breaking up process at humps. Methodology. Pushing process simulation was done based on adapted under the shunting conditions traction calculations. In addition, the features of shunting locomotives work at the humps were taken into account. In order to realize the current pushing mode the special algorithm of hump locomotive controlling, which along with the safety shunting operation requirements takes into account behavioral factors associated with engineer control actions was applied. This algorithm provides train smooth acceleration and further movement with speed, which is close to the set speed. Hump locomotive fuel consumptions were determined based on the amount of mechanical work performed by locomotive traction. Findings. The simulation model of train pushing process was developed and combined with existing cut rolling down model. Cut initial velocity is determined during simulation process. The obtained initial velocity is used for further cut rolling process modeling. In addition, the modeling resulted in sufficiently accurate determination of the fuel rates consumed for train breaking-up. Originality. The simulation model of train breaking-up process at the humps, which in contrast to the existing models allows reproducing complexly all the elements of this process in detail

Breaking Up Sitting with Light-Intensity Physical Activity: Implications for Shift-Workers

Directory of Open Access Journals (Sweden)

Grace E. Vincent

2017-10-01

Full Text Available Prolonged sitting, restricted sleep, and circadian disruption are all independent risk factors for non-communicable diseases. Previous research has demonstrated that breaking up sitting with light-intensity physical activity has clear benefits for the health of day workers, but these findings may not apply in the presence of sleep restriction and/or circadian disruption—both of which are commonly experienced by shift-workers. Specifically, sleep restriction, and circadian disruption result in acute physiological changes that may offset the benefits of breaking up sitting. This commentary will explore the potential benefits of breaking up sitting for health, work performance, and subsequent sleep in shift-workers. Future areas of research designed to understand the mechanisms by which prolonged sitting and shift work impact worker health and safety and to support the design of effective occupational health and safety interventions are proposed.

Few body problems in nuclear and particle physics

International Nuclear Information System (INIS)

Slobodrian, R.J.; Cujec, B.; Ramavataram, K.

1975-01-01

Nucleon-nucleon interactions at all energies, meson-nucleon and meson-deuteron interactions, nuclear bremsstrahlung, on-shell and off-shell interactions, final-state interactions, bound and scattering states, few-body forces, polarization phenomena, short range correlations, quasi-free scattering, composite hadron models, subnucleon structure, multiparticle and coherent production processes, break-up reactions, electrodisintegration, relativistic effects and future resources in nuclear and particle physics are discussed in relation to the state of few-body physics in 1974. (B.F.G.)

Charge symmetry breaking in the reaction np→dπ0

International Nuclear Information System (INIS)

Niskanen, J.A.; Sebestyen, M.; Thomas, A.W.

1988-01-01

By extending a coupled channels model which has proven successful in describing the reaction pp→π + d, we make predictions for charge symmetry breaking effects in the reaction np→dπ 0 . We find that nucleon and delta mass differences at vertices where pions are emitted or absorbed are important (as for np elastic scattering). However, eta-π 0 mixing is also important in pion production. We predict forward-backward asymmetries in the pion production differential cross section as large as 1% (for laboratory energies below 800 MeV). The asymmetries induced in polarization observables are small

Isospin-breaking nuclear forces in QCD sum rules and Nolen-Schiffer anomaly

International Nuclear Information System (INIS)

Drukarev, E.G.; Ryskin, M.G.

1994-01-01

We use QCD sum rules to investigate isospin-breaking effects in nuclear matter. The isospin-breaking condensate left angle NM vertical stroke uu-dd vertical stroke NM right angle is shown to play an important role. In a reasonable model the neutron becomes (0.9±0.6) MeV more bound than the proton, providing a possible solution for the Nolen-Schiffer anomaly. The various contributions to the value are analysed. The possible consequences for nucleon-nucleon isospin-breaking forces are discussed. ((orig.))

Nuclear structure in deep-inelastic reactions

International Nuclear Information System (INIS)

Rehm, K.E.

1986-01-01

The paper concentrates on recent deep inelastic experiments conducted at Argonne National Laboratory and the nuclear structure effects evident in reactions between super heavy nuclei. Experiments indicate that these reactions evolve gradually from simple transfer processes which have been studied extensively for lighter nuclei such as 16 O, suggesting a theoretical approach connecting the one-step DWBA theory to the multistep statistical models of nuclear reactions. This transition between quasi-elastic and deep inelastic reactions is achieved by a simple random walk model. Some typical examples of nuclear structure effects are shown. 24 refs., 9 figs

MULTIPHASE DROPLET/SLUG BREAK-UP MECHANISM IN MICROFLUIDIC T-JUNCTIONS AT VARIOUS WEBER NUMBERS

Directory of Open Access Journals (Sweden)

Wan Leng (Dawn Leow

2011-10-01

Full Text Available Normal 0 false false false EN-MY X-NONE X-NONE The formation of immiscible liquid droplets, or slugs, in microchannels features the advantages of volume control and mixing enhancement over single-phase microflows. Although the applications of droplet-based microfluidics have been widely demonstrated, the fundamental physics governing droplet break-up remains an area of active research. This study defines an effective Weber (Weeff number that characterizes the interplay of interfacial tension, shear stress and channel pressure drop in driving slug formation in T-junction microchannel for a relative range of low, intermediate and high flow rates. The immiscible fluid system in this study consists of Tetradecane slug formation in Acetonitrile. The progressive deformation of slug interfaces during break-up events is observed. Experimental results indicate that, at a relatively low Weeff, clean slug break-up occurs at the intersection of the side and main channels. At intermediate Weeff, the connecting neck of the dispersed phase is stretched to a short and thin trail of laminar flow prior to breaking up a short distance downstream of the T-junction. At a relatively high Weeff, the connecting neck develops into a longer and thicker trail of laminar flow that breaks up further downstream of the main channel.

Nuclear Astrophysics and Neutron Induced Reactions: Quasi-Free Reactions and RIBs

International Nuclear Information System (INIS)

Cherubini, S.; Spitaleri, C.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Coc, A.; Kubono, S.; Binh, D. N.; Hayakawa, S.; Wakabayashi, Y.; Yamaguchi, H.; Burjan, V.; Kroha, V.; De Sereville, N.

2010-01-01

The use of quasi-free reactions in studying nuclear reactions between charged particles of astrophysical interest has received much attention over the last two decades. The Trojan Horse Method is based on this approach and it has been used to study a number of reactions relevant for Nuclear Astrophysics. Recently we applied this method to the study of nuclear reactions that involve radioactive species, namely to the study of the 18 F+p→ 15 O+α process at temperatures corresponding to the energies available in the classical novae scenario. Quasi-free reactions can also be exploited to study processes induced by neutrons. This technique is particularly interesting when applied to reaction induced by neutrons on unstable short-lived nuclei. Such processes are very important in the nucleosynthesis of elements in the sand r-processes scenarios and this technique can give hints for solving key questions in nuclear astrophysics where direct measurements are practically impossible.

Multistep processes in nuclear reactions

International Nuclear Information System (INIS)

Hodgson, P.E.

1988-01-01

The theories of nuclear reactions are reviewed with particular attention to the recent work on multistep processes. The evidence for compound nucleus and direct interaction reactions is described together with the results of comparisons between theories and experimental data. These theories have now proved inadequate, and there is evidence for multistep processes that take place after the initial direct stage but long before the attainment of the statistical equilibrium characteristic of compound nucleus processes. The theories of these reactions are described and it is shown how they can account for the experimental data and thus give a comprehensive understanding of nuclear reactions. (author)

Lin's theory of flux and nuclear reactions

International Nuclear Information System (INIS)

Ping-Wha Lin

2002-01-01

Mathematical development of Lin's theory of flux is presented. Based on the Theory, when a chemical reaction system is subjected to a high time rate of temperature change, it changes from equilibrium to non-equilibrium conditions. It is proved mathematically that, when a gas system is subjected to a high time rate of temperature increase, the activities of particles (molecules, atoms or nuclei, and electrons) are increased: the particles are accelerated; frequencies and amplitudes of electron and atomic vibrations in a molecule increased; average kinetic energy of the particles increased; atomic bonds are ruptured; electrons are caused to leave their orbits. If most or all of the electrons leave their orbits, the gas fluid becomes plasma, which is very active chemically. The acceleration of nuclei in the dynamic condition can lead to nuclear reactions. In the pilot plant studies conducted at Research Triangle, NC, USA, for SO 2 conversion to SO 3 by rapid heating, a 10-ft high vertically fired combustor (VFC) was used. Air containing 0.5% SO 2 is forced continuously through the VFC, where it is heated by burners for conversion of SO 2 to SO 3 . During the idle period of operation, no external heat is added to the system by turning off the burners. It is observed that, as the air passing through the VFC during the idle period of sixteen hours, the temperature of the flowing air consistently rises up rapidly from ambient temperature (90 deg F) at inlet of the VFC to an average temperature as high as 582 deg F (in the range of 840 deg F to 455 deg F) at one section of the VFC, an increase of about 500 deg F. The air flow temperature increase of such large magnitude and long duration clearly indicates that nuclear reactions are present in VFC. It is also found that the water vapour in the air stream has completely disappeared in the VFC, for no sulphuric acid formation resulting from the reaction of water and SO 3 is detected there. Presumably, the water vapour in the

Theoretical studies in nuclear reactions and nuclear structure

International Nuclear Information System (INIS)

Wallace, S.J.

1991-05-01

This report discusses topics in the following areas: Hadronic structure; hadrons in nuclei; hot hadronic matter; relativistic nuclear physics and NN interaction; leptonic emissions from high-Z heavy ion collisions; theoretical studies of heavy ion dynamics; nuclear pre-equilibrium reactions; classical chaotic dynamics and nuclear structure; and, theory of nuclear fission

Nuclear reactions video (knowledge base on low energy nuclear physics)

International Nuclear Information System (INIS)

Zagrebaev, V.; Kozhin, A.

1999-01-01

The NRV (nuclear reactions video) is an open and permanently extended global system of management and graphical representation of nuclear data and video-graphic computer simulation of low energy nuclear dynamics. It consists of a complete and renewed nuclear database and well known theoretical models of low energy nuclear reactions altogether forming the 'low energy nuclear knowledge base'. The NRV solves two main problems: 1) fast and visualized obtaining and processing experimental data on nuclear structure and nuclear reactions; 2) possibility for any inexperienced user to analyze experimental data within reliable commonly used models of nuclear dynamics. The system is based on the realization of the following principal things: the net and code compatibility with the main existing nuclear databases; maximal simplicity in handling: extended menu, friendly graphical interface, hypertext description of the models, and so on; maximal visualization of input data, dynamics of studied processes and final results by means of real three-dimensional images, plots, tables and formulas and a three-dimensional animation. All the codes are composed as the real Windows applications and work under Windows 95/NT

CONFERENCE: Nuclear visions

International Nuclear Information System (INIS)

Anon.

1986-01-01

Last summer, four hundred visitors of about 30 different nationalities descended on the ancient town of Visby on the Swedish island of Gotland for the Second International Conference on Nucleus-Nucleus Collisions. For the conference itself, sessions were organized not according to conventional topics like low, intermediate and high energy reactions, but along phenomena-related lines that brought listeners together instead of splitting them up. Examples were 'phase transitions', 'new facilities' and 'breaking nuclear matter into pieces'

Four-body calculation above four-body break-up threshold

International Nuclear Information System (INIS)

Uzu, E.; Kamada, H.; Koike, Y.

2005-01-01

The complex energy method [Prog. Theor. Phys. 109, 869L (2003)] is applied to the four body Faddeev-Yakubovsky equations in the four nucleon system. We obtain a well converged solution in all energy regions below and above the four nucleon break-up threshold

Nuclear reactions

International Nuclear Information System (INIS)

Corner, J.; Richardson, K.; Fenton, N.

1990-01-01

Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

CSNI specialist meeting on leak-before-break in nuclear reactor piping: proceedings

Energy Technology Data Exchange (ETDEWEB)

1984-08-01

On September 1 and 2, 1983, the CSNI subcommittee on primary system integrity held a special meeting in Monterey, California, on the subject of leak-before-break in nuclear reactor piping systems. The purpose of the meeting was to provide an international forum for the exchange of ideas, positions, and research results; to identify areas requiring additional research and development; and to determine the general attitude toward acceptance of the leak-before-break concept. The importance of the leak-before-break issue was evidenced by excellent attendance at the meeting and through active participation by the meeting attendees. Approximately 125 people representing fifteen different nations attended the meeting. The meeting was divided into four technical sessions addressing the following areas: Application of Piping Fracture Mechanics to Leak-Before Break, Leak Rate and Leak Detection, Leak-Before-Break Studies, Methods and Results, Current and Proposed Positions on Leak-Before-Break.

CSNI specialist meeting on leak-before-break in nuclear reactor piping: proceedings

International Nuclear Information System (INIS)

1984-08-01

On September 1 and 2, 1983, the CSNI subcommittee on primary system integrity held a special meeting in Monterey, California, on the subject of leak-before-break in nuclear reactor piping systems. The purpose of the meeting was to provide an international forum for the exchange of ideas, positions, and research results; to identify areas requiring additional research and development; and to determine the general attitude toward acceptance of the leak-before-break concept. The importance of the leak-before-break issue was evidenced by excellent attendance at the meeting and through active participation by the meeting attendees. Approximately 125 people representing fifteen different nations attended the meeting. The meeting was divided into four technical sessions addressing the following areas: Application of Piping Fracture Mechanics to Leak-Before Break, Leak Rate and Leak Detection, Leak-Before-Break Studies, Methods and Results, Current and Proposed Positions on Leak-Before-Break

Nuclear reaction inputs based on effective interactions

Energy Technology Data Exchange (ETDEWEB)

Hilaire, S.; Peru, S.; Dubray, N.; Dupuis, M.; Bauge, E. [CEA, DAM, DIF, Arpajon (France); Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium)

2016-11-15

Extensive nuclear structure studies have been performed for decades using effective interactions as sole input. They have shown a remarkable ability to describe rather accurately many types of nuclear properties. In the early 2000 s, a major effort has been engaged to produce nuclear reaction input data out of the Gogny interaction, in order to challenge its quality also with respect to nuclear reaction observables. The status of this project, well advanced today thanks to the use of modern computers as well as modern nuclear reaction codes, is reviewed and future developments are discussed. (orig.)

Alterations in the nuclear matrix protein mass correlate with heat-induced inhibition of DNA single-strand-break repair

International Nuclear Information System (INIS)

Warters, R.L.; Brizgys, L.M.; Lyons, B.W.

1987-01-01

The total protein mass co-isolating with the nuclear matrix or nucleoid from Chinese hamster ovary (CHO) cells was observed to increase in heated cells as a function of increasing exposure temperature between 43 0 C and 45 0 C or of exposure time at any temperature. The sedimentation distance of the CHO cell nucleoid in sucrose gradients increased with increasing exposure time at 45 0 C. Both these nuclear alterations correlated in a log-linear manner with heat-induced inhibition of DNA strand break repair. A two-fold threshold increase in nuclear matrix protein mass preceded any substantial inhibition of repair of DNA single-strand breaks. When preheated cells were incubated at 37 0 C the nuclear matrix protein mass and nucleoid sedimentation recovered with a half-time of about 5 h, while DNA single-strand-break repair recovered with a half-time of about 2 h. When preheated cells were placed at 41 0 C a further increase was observed in the nuclear matrix protein mass and the half-time of DNA strand break repair, while nucleoid sedimentation recovered toward control values. These results implicate alterations in the protein mass of the nuclear matrix in heat-induced inhibition of repair of DNA single-strand breaks. (author)

Proton induced nuclear reactions on cadmium up 17 MeV

International Nuclear Information System (INIS)

Al-Abyad, M.

2012-01-01

The cross-sections of proton induced reactions on nat Cd targets was studied in the energy range from threshold up to 17 MeV, using a stacked-foil irradiation technique and classical gamma-spectroscopy. We measured the formation cross-sections of the radioisotopes 109g,110m,110,111g,113m,114m,115m,116m In The obtained excitation functions were compared with the earlier published data and the theoretical model calculations by the codes ALICE-IPPE, EMPIRE and TALYS .

Break-up of New Orleans Households after Hurricane Katrina

Science.gov (United States)

Rendall, Michael S.

2011-01-01

Theory and evidence on disaster-induced population displacement have focused on individual and population-subgroup characteristics. Less is known about impacts on households. I estimate excess incidence of household break-up due to Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads and non–household heads (N = 242), traced just over a year later, with a matched sample from a nationally representative survey over an equivalent period. One in three among all adult non–household heads, and one in two among adult children of household heads, had separated from the household head 1 year post-Katrina. These rates were, respectively, 2.2 and 2.7 times higher than national rates. A 50% higher prevalence of adult children living with parents in pre-Katrina New Orleans than nationally increased the hurricane’s impact on household break-up. Attention to living arrangements as a dimension of social vulnerability in disaster recovery is suggested. PMID:21709733

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

1999-01-01

Full text: The Department of Nuclear Reactions had a very productive year. The following reports cover three major domains of our activities: nuclear, material and atomic physics. One of the current questions in modern nuclear physics is question of the phase transitions in nuclear matter. Our physicists, the members of the ALADIN Collaboration at Gesellschaft fuer Schwerionenforschung, participated in new experiments exploring properties of highly excited nuclear matter and the phenomenon of the liquid - gas phase transition. The experiments yielded a number of important results. Details can be found in the three short reports presented in this volume. Structure of a nucleon is another important subject of nuclear science research. In the last year energy region of Δ resonance has been investigated by means of charge exchange reaction. The experiment was performed at Laboratory National Saturne in Saclay by SPESIV-π collaboration consisting of physicist from Institute of Nuclear Physics Orsay, Niels Bohr Institute Copenhagen and from our Department. The main achievement of the experiment was evidence for a Δ - hole attraction in the spin longitudinal channel. Reactions induced by radioactive ion beams such as 6 He recently attract a lot of interest. There exist some evidences that the 6 He nucleus has a two-neutron halo structure similar to that well established for 11 Li. An analysis of 6 He + 4 He scattering data reported in this volume revealed some similarities between the loosely bound 6 Li nucleus and the neutron rich 6 He. Research in material physics has focused on two basic topics: a crystallographic model of uranium dioxide, a material currently used as a nuclear fuel and transformations of defects in GaAs crystals at low temperature. The investigations have been carried out in a wide collaboration with scientists from the University of Jena, Research Center Karlsruhe and Centre de Spectrometrie Nucleaire Orsay. Some experiments have been performed at

Nuclear reaction database on Meme Media

International Nuclear Information System (INIS)

Ohbayashi, Yoshihide; Masui, Hiroshi; Aoyama, Shigeyoshi; Kato, Kiyoshi; Chiba, Masaki

2000-01-01

We have developed the system of charged particle nuclear reaction data (CPND) on the IntelligentPad architecture. We called the system CONTIP, which is an abbreviation of 'Creative, Cooperative and Cultural Objects for Nuclear data and Tools'. NRDF (Nuclear Reaction Data File), which is a kind of CPND compilation, is applied as an application example. Although CONTIP is currently applied to NRDF, the framework can be generalized to use the other nuclear database. We will develop CONTIP to give the framework for effective utilization of nuclear data. (author)

Nuclear Reactions for Astrophysics and Other Applications

Energy Technology Data Exchange (ETDEWEB)

Escher, J E; Burke, J T; Dietrich, F S; Scielzo, N D; Ressler, J J

2011-03-01

Cross sections for compound-nuclear reactions are required for many applications. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

Central Atlantic Break-up: A competition between CAMP Hotspot and thinning rate.

Science.gov (United States)

Sapin, F.; Maurin, T.

2017-12-01

The break-up of the Central Atlantic is known to have ended at about 190Myrs while the CAMP (Central Atlantic Magmatic Province) was still active. Several seismic lines, acquired recently in the deep offshore Senegal and Mauritanian domain, provide detailed images of continent-ocean transition and the oceanic crust architecture. Their interpretation is the opportunity to describe the progressive interaction between the hot spot activity, the architecture and timing of break up and the oceanic crust production. In the North, seismic data and gravity/magnetic inversions suggest an extremely thinned continental crust with possible mantle exhumation. In the South, the continental crust is thick and the transition to oceanic crust is sharp. In addition, three oceanic crust facies were described along the margin in an extremely slow spreading ridge setting ( 0.8cm/yr during the first 20Myrs): facies (1) with a poorly imaged Moho and a strongly faulted thin oceanic crust or exhumed mantle; facies (2) with an extensively faulted 6km thick oceanic crust; facies (3) with abnormally thick (9km) oceanic crust marked by SDR-type reflections. They are diachronous from North to South and the two first one disappear southwards and (facies 3) being younger toward the North. Only a single very thick oceanic crust (12-14km) remains in front of the Guinea Plateau. We concluded that, in the South, the break-up had been forced through a thick or thickened continental crust due to the remnant activity of the CAMP Hotspot. In the North, the magmatic pulse arrived far after the break-up during the spreading and the thinning of the continental crust could lead to hyper extension. This evolution emphasizes that the architecture, and thus processes leading to the break-up can vary a lot considering the influence of thermal vertical forces (mantle dynamics/hotspot/magmatism) and mechanical horizontal forces (plate movement/faulting/spreading), both of them being necessary for a rift to succeed.

Electromagnetic reactions of few-body systems with the Lorentz integral transform method

International Nuclear Information System (INIS)

Leidemann, W.

2007-01-01

Various electromagnetic few-body break-up reactions into the many-body continuum are calculated microscopically with the Lorentz integral transform (LIT) method. For three- and four-body nuclei the nuclear Hamiltonian includes two- and three-nucleon forces, while semirealistic interactions are used in case of six- and seven-body systems. Comparisons with experimental data are discussed. In addition various interesting aspects of the 4 He photodisintegration are studied: investigation of a tetrahedrical symmetry of 4 He and a test of non-local nuclear force models via the induced two-body currents

Theory of nuclear reactions, with applications to heavy ion scattering reactions

International Nuclear Information System (INIS)

Youssef, M.S.A.

1981-01-01

Nuclear science to day, has gained its stature through the pioneer work of both theorists and experimentalists within its two main divisions, Nuclear Reaction and Nuclear Structure theories. Our main interest in this theoretical work in nuclear reaction theory is focused on three topics, come under the headings of three parts which are the constituents of the present paper. Part 1 is concerned with ''Contributions to the theory of Threshold phenomena in nuclear reactions; cluster threshold states in heavy ion reactions''. Part II is devoted to ''Hermiticity of the Laplacian operator, R-matrix theories and direct interaction theory'', while part xII is ascribed to ''Heavy ion transfer reactions and scattering''. The aforementioned selected topics are the backbones of this thesis, which starts with general introduction giving a brief account about the material included in. In each part, investiqations are given in an extended manner through several chapters. Finally, the thesis is ended eith the chapter on ''General Discussions and Conclusions''. Appendices, references, and figure captions are found at the end of each part, the matter which we believe to facilitate much the reading through of the thesis. The first two parts are based (to some extent) on the same formal background (R-matrix, Kapur-Peierls-theories) and they converge to solve some physical problems originating from flux conservation laws in nuclear reactions, while the third part is indirect related to the first two; in principle it joins the other two parts under computational aspects. All of them after all, form the solidarity of the material included in the thesis. (author)

Nuclear reaction database on Meme Media

Energy Technology Data Exchange (ETDEWEB)

Ohbayashi, Yoshihide; Masui, Hiroshi [Meme Media Laboratory, Hokkaido University, Sapporo, Hokkaido (Japan); Aoyama, Shigeyoshi [Information Processing Center, Kitami Institute of Technology, Kitami, Hokkaido (Japan); Kato, Kiyoshi [Division of Physics, Graduate School of Science, Hokkaido Univ., Sapporo, Hokkaido (Japan); Chiba, Masaki [Division of Social Information, Sapporo Gakuin University, Ebetsu, Hokkaido (Japan)

2000-03-01

We have developed the system of charged particle nuclear reaction data (CPND) on the IntelligentPad architecture. We called the system CONTIP, which is an abbreviation of 'Creative, Cooperative and Cultural Objects for Nuclear data and Tools'. NRDF (Nuclear Reaction Data File), which is a kind of CPND compilation, is applied as an application example. Although CONTIP is currently applied to NRDF, the framework can be generalized to use the othernuclear database. We will develop CONTIP to give the framework for effective utilization of nuclear data. (author)

Study of the break reaction of Be11 on Ti48 target; the towing mode: a spectroscopic tool for the study of nuclei

International Nuclear Information System (INIS)

Lima, V.

2004-10-01

In a towing mode reaction the projectile picks up a nucleon from the target and then breaks up by emitting one nucleon. The velocity of the emitted nucleon is boosted by the projectile velocity, leading to the emission of the nucleon in a narrow cone around the direction of the scattered projectile. This work is dedicated to the towing mode in halo nuclei such as Be 11 . The experiment was performed at Ganil facility by bombarding a Ti 48 target with a 41 MeV per nucleon Be 11 beam, the reaction studied is: Ti 48 (Be 11 , Be 10 + n + γ). The first chapter reviews the various nuclear processes that take place when 2 nuclei collide with a particular attention for the towing mode. The second chapter is dedicated to solving the time dependant Schroedinger equation (TDSE) in order to assess the impact of various parameters such as incident energy, target charge or the linking energy of the nucleon, on the towing mode reaction. The third chapter deals with the experimental equipment and set-up including detectors and the data acquisition system. Computerized simulations have been performed in order to assess the efficiency of the detecting system, they are presented in the fourth chapter. A comparison between experimental data and the results from TDSE solving, concerning the energy spectra of the emitted particles, has enabled the author to deduce the spectroscopic factors for the different contributions of the fundamental state of Be 11 , they are presented in the last chapter. The cross-sections of the towing mode are of the magnitude of several tens of milli-barns in the case of weakly bound nuclei like Be 11 which make it an efficient tool to study intern structure of nuclei. (A.C.)

High-lying neutron hole strengths observed in pick-up reactions

International Nuclear Information System (INIS)

Gales, S.

1980-01-01

Neutron-hole states in orbits well below the Fermi surface have been observed in a number of medium-heavy nuclei from A=90 to 209 using one nucleon pick-up reactions. The excitation energies, angular distributions of such broad and enhanced structures will be discussed. The fragmentation of the neutron-hole strengths as well as the spreading of such simple mode of excitations into more complex states are compared to recent calculations within the quasiparticle-phonon or the single particle-vibration coupling nuclear models. We report on recent measurements of J for inner-hole states in 89 Zr and 115 Sn 119 Sn using the analyzing power of the (p,d) and (d,t) reactions. Large enhancement of cross-sections are observed at high excitation energy in the study of the (p,t) reactions on Zr, Cd, Sn, Te and Sm isotopes. The systematic features of such high-lying excitation are related to the ones observed in one neutron pick-up experiments. The origin of such concentration of two neutron-hole strengths in Cd and Sn isotopes will be discussed. Preliminary results obtained in the study of the (α, 6 He) reaction at 218 MeV incident energy on 90 Zr, 118 Sn and 208 Pb targets are presented and compared to the (p,t) results. Finally the properties of hole-analog states populated in neutron pick-up reactions (from 90 Zr to 208 Pb) will be presented

Digital decoupling and disentangling: towards design for romantic break up

NARCIS (Netherlands)

Herron, D.; Moncur, W.; van den Hoven, E.

2017-01-01

Romantic relationships are often facilitated through digital technologies, such as social networking sites and communication services. They are also facilitated through 'digital possessions', such as messages sent to mobile devices and photos shared through social media. When individuals break up,

Nuclear fission, chain reaction and criticality

International Nuclear Information System (INIS)

Reuss, Paul

2016-01-01

Criticality is, notably for nuclear reactors, the status which separates the case of a fission chain reaction which inexorably decays, from that of a reaction which grows faster and faster until a counter-reaction occurs. If this status is an objective in nuclear reactors, it must not be reached or exceeded in any case in other types of installations in which fissile materials are handled (fabrication, transports, nuclear fuel processing). The author proposes an insight into this notion of criticality, discusses elements of neutron science which allow the multiplication factor to be assessed, analyses accidental scenarios which may happen, and presents associated experiments and computation codes

Transport description of damped nuclear reactions

International Nuclear Information System (INIS)

Randrup, J.

1984-01-01

This lecture series is concerned with the transport description of damped nuclear reactions. Part 1 is an elementary introduction to the general transport theory of nuclear dynamics. It can be read without any special knowledge of the field, although basic quantum mechanics is required for the formal derivation of the general expressions for the transport coefficients. The results can also be used in a wider context than the present one. Part 2 gives the student an up-to-date orientation about recent progress in the understanding of the angular-momentum variables in damped reactions. The emphasis is here on the qualitative understanding of the physics rather than the, at times somewhat tedious, formal derivations. More detailed presentations are due to be published soon. By necessity entire topics have been omitted. For example, no discussion is given of the calculation of the form factors, and the several instructive applications of the theory to transport of mass and change are not covered at all. For these topics they refer to the literature. It is hoped that the present notes provide a sufficient basis to make the literature on the subject accessible to the student

Elements from chlorine to calcium nuclear reactions

CERN Document Server

Kunz, Wunibald

1968-01-01

Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

Breaking up with Deleuze: Desire and Valuing the Irreconcilable

Science.gov (United States)

Tuck, Eve

2010-01-01

In this article, Eve Tuck grapples with Gilles Deleuze's conceptualization of desire, finding it simultaneously generative and unsatisfying. Recognizing that Deleuze will not "say" what Tuck wants him to say about desire--that it is smart, and constitutes expertise--Tuck reasons that there is only one thing she can do: break up with Deleuze. The…

Nuclear data needs in nuclear astrophysics: Charged-particle reactions

International Nuclear Information System (INIS)

Smith, Michael S.

2001-01-01

Progress in understanding a diverse range of astrophysical phenomena - such as the Big Bang, the Sun, the evolution of stars, and stellar explosions - can be significantly aided by improved compilation, evaluation, and dissemination of charged-particle nuclear reaction data. A summary of the charged-particle reaction data needs in these and other astrophysical scenarios is presented, along with recommended future nuclear data projects. (author)

Evaluation of the UP4FUN intervention: a cluster randomized trial to reduce and break up sitting time in European 10-12-year-old children.

Directory of Open Access Journals (Sweden)

Frøydis N Vik

Full Text Available The UP4FUN intervention is a family-involved school-based intervention aiming at reducing and breaking up sitting time at home (with special emphasis on screen time, and breaking up sitting time in school among 10-12 year olds in Europe. The purpose of the present paper was to evaluate its short term effects.A total of 3147 pupils from Belgium, Germany, Greece, Hungary and Norway participated in a school-randomized controlled trial. The intervention included 1-2 school lessons per week for a period of six weeks, along with assignments for the children and their parents. Screen time and breaking up sitting time were registered by self-report and total sedentary time and breaking up sitting time by accelerometry. The effect of the intervention on these behaviors was evaluated by multilevel regression analyses. All analyses were adjusted for baseline values and gender. Significance level was p≤0.01. No significant intervention effects were observed, neither for self-reported TV/DVD or computer/game console time, nor for accelerometer-assessed total sedentary time and number of breaks in sitting time. The intervention group, however, reported more positive attitudes towards (β = 0.25 (95% CI 0.11, 0.38 and preferences/liking for (β = 0.20 (95% CI 0.08, 0.32 breaking up sitting time than the control group.No significant intervention effect on self-reported screen time or accelerometer-assessed sedentary time or breaks in sitting time was observed, but positive effects on beliefs regarding breaking up sitting time were found in favor of the intervention group. Overall, these results do not warrant wider dissemination of the present UP4FUN intervention.International Standard Randomized Controlled Trial Number Registry ISRCTN34562078.

Experimental study on spray break-up and atomization processes from GDI injector using high injection pressure up to 30 MPa

International Nuclear Information System (INIS)

Lee, Sanghoon; Park, Sungwook

2014-01-01

Highlights: • We obtain distribution of droplet velocity and diameter using PDPA system. • Transition of a jet break-up processes is visualized using Nd:Yag sheet laser system. • Elevated injection pressure can activate a jet break-up processes. • A limit in injection pressure to enhance droplet atomization is observed. -- Abstract: This paper focuses on the influence of injection pressures up to 30 MPa on single liquid jet break-up and atomization processes. For this purpose, a single jet from a multi-hole GDI injector has been characterized performing visualization and PDPA (phase Doppler particle analyzer) experiments. Using a thin sheet of light generated by a Nd:Yag laser and capturing a sequence of jet development images with a CCD camera, the internal structure was visualized. In order to quantify the droplet diameter and velocity, a 2-D PDPA system were carried out in addition to the spray visualization. Analyzing the images of the internal structure of jet and the result of PDPA, including droplet diameter and velocity distribution with increasing injection pressure up to 30 MPa, the elevated injection pressure on a jet break-up and atomization was characterized. Our experimental results show the existence of a leading edge of the jet observed at the initial stage of injection. This phenomenon revealed relatively large droplets ahead of the main jet then disappeared quickly as lose the droplets momentum. Furthermore, for all injection pressures, unique ‘branch-like structure’ was observed when the jet was fully developed. This structure had many counter rotating branches related to the effect of air-entrainment and rapidly broken down into droplet clusters and droplets. Especially, as increased injection pressure, the time to exhibit the structure and distance between two branches were decreased. In addition, based on the results of droplet diameter and velocity distribution at various injection pressures, we confirmed that the injection

Japan Nuclear Reaction Data Centre (JCPRG) Progress Report

International Nuclear Information System (INIS)

2011-01-01

In this report, we give a brief review of the activities carried out by the ''Japan Nuclear Reaction Data Centre (JCPRG)'' since the last NRDC meeting in 2009. The main subjects of our activities are; (1) reaction data compilation, (2) evaluation of the astrophysical nuclear reaction data for light nuclei, and (3) cooperation of nuclear data activities in Asia. Our activities in detail are as follows. a) New reaction data compilation (NRDF and EXFOR) b) Conversion of old NRDF to EXFOR c) Bibliography compilation (CINDA) d) Evaluation of astrophysical nuclear reaction data based on theoretical calculations for light nuclei e) Collaboration among nuclear data physicists in Asia for the EXFOR compilation to form a stable base f) Database maintenance and services (NRDF, EXFOR/ENDF and CINDA) g) Development of software systems (GSYS) h) Customer services

Nuclear reactions. An introduction

Energy Technology Data Exchange (ETDEWEB)

Paetz gen. Schieck, Hans [Koeln Univ. (Germany). Inst. fuer Kernphysik

2014-03-01

Modern, self-contained introduction to the subject matter. Emphasizes the interplay between theory and experiment. Course-tested tutorial style, contains many derivations. Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown - mainly by performing scattering experiments with electrons, muons, and neutrinos - to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction. The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no end in sight for either theoretical or experimental developments as shown e.g. by the recent need to introduce more sophisticated three-body interactions to account for an improved picture of nuclear structure and reactions. Yet, it turns out that the internal structure of the nucleons has comparatively little influence on the behavior of the nucleons in nuclei, and nuclear physics - especially nuclear structure and reactions - is thus a field of science in its own right, without much recourse to subnuclear degrees of freedom. This book collects essential material that was presented in the form of lectures notes in nuclear physics courses for graduate students at the University of Cologne. It follows the course's approach, conveying the subject matter by combining experimental facts and

Nuclear reactions. An introduction

International Nuclear Information System (INIS)

Paetz gen. Schieck, Hans

2014-01-01

Modern, self-contained introduction to the subject matter. Emphasizes the interplay between theory and experiment. Course-tested tutorial style, contains many derivations. Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown - mainly by performing scattering experiments with electrons, muons, and neutrinos - to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction. The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no end in sight for either theoretical or experimental developments as shown e.g. by the recent need to introduce more sophisticated three-body interactions to account for an improved picture of nuclear structure and reactions. Yet, it turns out that the internal structure of the nucleons has comparatively little influence on the behavior of the nucleons in nuclei, and nuclear physics - especially nuclear structure and reactions - is thus a field of science in its own right, without much recourse to subnuclear degrees of freedom. This book collects essential material that was presented in the form of lectures notes in nuclear physics courses for graduate students at the University of Cologne. It follows the course's approach, conveying the subject matter by combining experimental facts and experimental

Statistical nuclear reactions

International Nuclear Information System (INIS)

Hilaire, S.

2001-01-01

A review of the statistical model of nuclear reactions is presented. The main relations are described, together with the ingredients necessary to perform practical calculations. In addition, a substantial overview of the width fluctuation correction factor is given. (author)

Experimental study and nuclear model calculations of {sup 3}He-induced nuclear reactions on zinc

Energy Technology Data Exchange (ETDEWEB)

Al-Abyad, M.; Mohamed, Gehan Y. [Nuclear Research Centre, Atomic Energy Authority, Physics Department (Cyclotron Facility), Cairo (Egypt); Ditroi, F.; Takacs, S.; Tarkanyi, F. [Hungarian Academy of Sciences (ATOMKI), Institute for Nuclear Research, Debrecen (Hungary)

2017-05-15

Excitation functions of {sup 3}He-induced nuclear reactions on natural zinc were measured using the standard stacked-foil technique and high-resolution gamma-ray spectrometry. From their threshold energies up to 27 MeV, the cross-sections for {sup nat}Zn ({sup 3}He,xn) {sup 69}Ge, {sup nat}Zn({sup 3}He,xnp) {sup 66,67,68}Ga, and {sup nat}Zn({sup 3}He,x){sup 62,65}Zn reactions were measured. The nuclear model codes TALYS-1.6, EMPIRE-3.2 and ALICE-IPPE were used to describe the formation of these products. The present data were compared with the theoretical results and with the available experimental data. Integral yields for some important radioisotopes were determined. (orig.)

Verification of cold nuclear fusion reaction, (1)

International Nuclear Information System (INIS)

Yoshida, Zenko; Aratono, Yasuyuki; Hirabayashi, Takakuni

1991-01-01

Can cold nuclear fusion reaction occur as is expected? If it occurs, what extent is its reaction probability? At present after 2 years elapsed since its beginning, the clear solution of these questions is not yet obtained. In many reaction systems employing different means, the experiments to confirm the cold nuclear fusion reaction have been attempted. In order to confirm that the nuclear fusion reaction of deuterium mutually has occurred, the neutrons, He-3, protons, tritium or generated heat, which were formed by the reaction and released from the system, are measured. Since it is considered that the frequency of the occurrence at normal temperature of the reaction is very low, it is necessary to select the most suitable method upon evaluating the limit of detection peculiar to the measuring methods. The methods of measuring neutrons, protons, gamma ray and generated heat, and the reaction systems by electrolytic process and dry process are explained. The detection of plural kinds of the reaction products and the confirmation of synchronism of signals are important. (K.I.)

Chiral Symmetry Breaking in Peptide Systems During Formation of Life on Earth

Science.gov (United States)

Konstantinov, Konstantin K.; Konstantinova, Alisa F.

2018-03-01

Chiral symmetry breaking in complex chemical systems with a large number of amino acids and a large number of similar reactions was considered. It was shown that effective averaging over similar reaction channels may result in very weak effective enantioselectivity of forward reactions, which does not allow most of the known models to result in chiral symmetry breaking during formation of life on Earth. Models with simple and catalytic synthesis of a single amino acid, formation of peptides up to length five, and sedimentation of insoluble pair of substances were considered. It was shown that depending on the model and the values of the parameters, chiral symmetry breaking may occur in up to about 10% out of all possible unique insoluble pair combinations even in the absence of any catalytic synthesis and that minimum total number of amino acids in the pair is 5. If weak enantioselective forward catalytic synthesis of amino acids is present, then the number of possible variants, in which chiral symmetry breaking may occur, increases substantially. It was shown that that the most interesting catalysts have zero or one amino acid of "incorrect" chirality. If the parameters of the model are adjusted in such a way to result in an increase of concentration of longer peptides, then catalysts with two amino acids of incorrect chirality start to appear at peptides of length five. Models of chiral symmetry breaking in the presence of epimerization were considered for peptides up to length three. It was shown that the range of parameters in which chiral symmetry breaking could occur significantly shrinks in comparison to previously considered models with peptides up to length two. An experiment of chiral symmetry breaking was proposed. The experiment consists of a three-step cycle: reversible catalytic synthesis of amino acids, reversible synthesis of peptides, and irreversible sedimentation of insoluble substances.

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2002-01-01

Full text: Department of Nuclear Reactions has had a very productive year. We have carried out our work in close collaborations with physicists from many laboratories, home and foreign. The following reports cover three major domains of our activities: nuclear, material and atomic physics. * Nuclear physics: In collaboration with scientists from Ukraine experimental studies of nuclear reaction induced by heavy ions from the Warsaw Cyclotron have been performed. The aim of the experiments is to study nuclear reactions leading to the exotic light nuclei in exit channels and energy dependence of the nucleus - nucleus interactions. Proton induced charge-exchange reactions were investigated theoretically by means of multistep-direct model. Good agreement with the experimental data was achieved. A novel approach to the problem of the nuclear liquid → gas phase transition was proposed, based on synergetics - a domain of science dealing with self-organization in macroscopic systems. Decay properties of the Roper resonance were studied. Final analysis of the analysing powers for the polarized deuterons scattered on protons was accomplished. Experimental programme of the near-threshold meson production in proton - proton scattering has been started in collaboration with Forschungszentrum. Juelich. * Atomic physics: Spectra of the X-rays emitted by energetic sulphur ions scattered off carbon atoms were analysed in order to study the role of the multiple charge states of the inner shells in the dynamics of the collision process. Ionization probabilities in collision of oxygen ions with gold atoms were measured. The observed disagreement of the experimental data with the theoretical predictions suggest a strong effect generated by the sub-shell couplings. * Materials research: Ion channelling method was applied to investigate transformation of the defects in Al x Ga 1-x As crystalline layers. Activities of our colleagues in didactics have grown considerably. Lectures

Japan Nuclear Reaction Data Centre (JCPRG), Progress Report

International Nuclear Information System (INIS)

Aikawa, M.

2012-01-01

In this report, we review the activities of Japan Nuclear Reaction Data Centre (JCPRG) since the last NRDC meeting in 2011. Our main objectives are as follows: a) Compilation of nuclear reaction data for two databases, NRDF and EXFOR b) Evaluation of astrophysical nuclear reaction data c) Development of software and systems d) Development of collaboration among Asian countries. (author)

Application of the Trojan Horse Method to study neutron induced reactions: the 17O(n, α14C reaction

Directory of Open Access Journals (Sweden)

Gulino M.

2014-03-01

Full Text Available The reaction 17O(n, α14C was studied using virtual neutrons coming from the quasi-free deuteron break-up in the three body reaction 17O+d → α+14C+p. This technique, called virtual neutron method, extends the Trojan Horse method to neutron-induced reactions allowing to study the reaction cross section avoiding the suppression effects coming from the penetrability of the centrifugal barrier. For incident neutron energies from thermal up to a few hundred keV, direct experiments have shown the population of two out of three expected excited states at energies 8213 keV and 8282 keV and the influence of the sub-threshold level at 8038 keV. In the present experiment the 18O excited state at E* = 8.125 MeV, missing in the direct measurement, is observed. The angular distributions of the populated resonances have been measured for the first time. The results unambiguously indicate the ability of the method to overcome the centrifugal barrier suppression effect and to pick out the contribution of the bare nuclear interaction.

Measurement of the D(n,2n)p reaction cross section up to 30 MeV

Energy Technology Data Exchange (ETDEWEB)

Laborie, J.M.; Ledoux, X.; Varignon, C.; Lazauskas, R.; Morillon, B.; Belier, G.; Arnal, N. [CEA Bruyeres-le-Chatel (DPTA/SPN), 91 (France). Dept. de Physique Theorique et Appliquee; Dore, D. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DAPNIA/SPhN), 91- Gif sur Yvette (France)

2008-07-01

This article presents a running experimental program to measure the neutron-induced deuteron break-up reaction between 5 and 10 MeV, and between 20 and 30 MeV. The measurements are performed with a C{sub 6}D{sub 6} detector as deuteron target placed in a beam line of the Tandem 7 MV accelerator in Cea facilities, dedicated to the use of a 4{pi} neutron detector which allows us to measure the two emitted neutrons. The total uncertainty is evaluated from 8.5 to 11 per cent. This experimental work is done in parallel with an ab-initio calculation of the reaction which is sum up in the text. Comparisons to the measured cross section are done together with CENDL2 and Endf/B-VII evaluations. (authors)

Measurement of the D(n,2n)p reaction cross section up to 30 MeV

International Nuclear Information System (INIS)

Laborie, J.M.; Ledoux, X.; Varignon, C.; Lazauskas, R.; Morillon, B.; Belier, G.; Arnal, N.

2008-01-01

This article presents a running experimental program to measure the neutron-induced deuteron break-up reaction between 5 and 10 MeV, and between 20 and 30 MeV. The measurements are performed with a C 6 D 6 detector as deuteron target placed in a beam line of the Tandem 7 MV accelerator in Cea facilities, dedicated to the use of a 4π neutron detector which allows us to measure the two emitted neutrons. The total uncertainty is evaluated from 8.5 to 11 per cent. This experimental work is done in parallel with an ab-initio calculation of the reaction which is sum up in the text. Comparisons to the measured cross section are done together with CENDL2 and Endf/B-VII evaluations. (authors)

Solar nuclear reactions

Energy Technology Data Exchange (ETDEWEB)

Kocharov, G

1978-04-01

The current state of neutrino solar astrophysics is outlined, showing the contradictions between the experimental results of solar neutrino detection and the standard solar models constructed on the basis of the star structure and development theory, which give values for high-energy neutrino fluxes considerably exceeding the upper experimental limit. A number of hypotheses interpreting the experimental results are summarized. The hypotheses are critically assessed and experiments are recommended for refining or verifying experimental data. Also dealt with are nuclear reactions in the Sun, as is the attempt to interpret the anomalous by high /sup 3/He fluxes from the Sun and the relatively small amounts of solar neutrinos and gamma quanta. The importance is emphasized of the simultaneous and complex measurement of the fluxes of neutrons, gamma radiation, and isotopes of hydrogen, helium, and boron from the Sun as indicators of nuclear reactions in the Sun.

Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52MeV.

Science.gov (United States)

Ditrói, F; Takács, S; Haba, H; Komori, Y; Aikawa, M

2016-12-01

Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. The radioisotope 117m Sn is a very important theranostic (therapeutic + diagnostic) radioisotope, so special care was taken to the results for that isotope. The well-established stacked foil technique followed by gamma-spectrometry with HPGe gamma spectrometers were used. The target and monitor foils in the stack were commercial high purity metal foils. From the irradiated targets 117m Sn, 113 Sn, 110 Sn, 117m,g In, 116m In, 115m In, 114m In, 113m In, 111 In, 110m,g In, 109m In, 108m,g In, 115g Cd and 111m Cd were identified and their excitation functions were derived. The results were compared with the data of the previous measurements from the literature and with the results of the theoretical nuclear reaction model code calculations TALYS 1.8 (TENDL-2015) and EMPIRE 3.2 (Malta). From the cross section curves thick target yields were calculated and compared with the available literature data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Large-eddy simulation of cavitating nozzle flow and primary jet break-up

Energy Technology Data Exchange (ETDEWEB)

Örley, F., E-mail: felix.oerley@aer.mw.tum.de; Trummler, T.; Mihatsch, M. S.; Schmidt, S. J.; Adams, N. A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany); Hickel, S. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany); Chair of Computational Aerodynamics, Faculty of Aerospace Engineering, TU Delft, Kluyverweg 1, 2629 HS Delft (Netherlands)

2015-08-15

We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating fluid model is based on a thermodynamic-equilibrium assumption. Compressibility of all phases enables full resolution of collapse-induced pressure wave dynamics. The thermodynamic model is embedded into an implicit large-eddy simulation (LES) environment. The considered configuration follows the general setup of a reference experiment and is a generic reproduction of a scaled-up fuel injector or control valve as found in an automotive engine. Due to the experimental conditions, it operates, however, at significantly lower pressures. LES results are compared to the experimental reference for validation. Three different operating points are studied, which differ in terms of the development of cavitation regions and the jet break-up characteristics. Observed differences between experimental and numerical data in some of the investigated cases can be caused by uncertainties in meeting nominal parameters by the experiment. The investigation reveals that three main mechanisms promote primary jet break-up: collapse-induced turbulent fluctuations near the outlet, entrainment of free gas into the nozzle, and collapse events inside the jet near the liquid-gas interface.

Department of Nuclear Reactions - Overview

International Nuclear Information System (INIS)

Budzanowski, A.

1999-01-01

Full text: The year 1998 can be considered as very successful both in harvesting important results from the existing collaborations as well as establishing new ones. In the frame of the COSY-11 collaboration cross section for η' production in p-p collision close to the threshold has been measured. In the region of excess energy between 1.5 and 4.1 MeV the η' cross sections are much lower than those of the π 0 and η production. There seems to be no indication that N * resonance doorway-like state governs the reaction mechanisms. The determined coupling constant g η'pp appears to be consistent with the prediction of the simple quark model. Results were published in Phys. Rev. Letters. Using the GEM detector, investigations of the isospin symmetry breaking were performed. Two reactions channels 3 Heπ 0 and 3 Hπ + from the reaction at proton momenta 700, 767, and 825 MeV/c were measured. Data analysis is in progress. The model of the meson cloud in the nucleon which is a speciality of our department has been successfully applied to explain the leading proton and neutron cross sections from the e + or e - proton collisions at the HERA ring. General formulas to calculate polarization of the particles with spin transmitted through the barrier in the presence of strong magnetic fields were obtained. New collaboration between our laboratory and the Institute for Nuclear Research in Kiev has been established. One PhD thesis was completed in the frame of this collaboration. We joined the new collaboration with Lund University concerning studies of hot nuclear matter properties using heavy ions from CELSIUS ring. First test of the phoswich detector for the forward wall was performed in Uppsala. Isoscalar giant dipole resonance strength distribution 3 ℎω has been evaluated in 208 Pb in the space of 1p1h and 2p2h excitation. The centroid energy of this state can directly be related to the nuclear incompressibility module. Our result indicates rather large values of

Transport description of damped nuclear reactions

International Nuclear Information System (INIS)

Randrup, J.

1983-04-01

Part I is an elementary introduction to the general transport theory of nuclear dynamics. It can be read without any special knowledge of the field, although basic quantum mechanics is required for the formal derivation of the general expression for the transport coefficients. The results can also be used in a wider context than the present one. Part II gives the student an up-to-date orientation about recent progress in the understanding of the angular-momentum variables in damped reactions. The emphasis is here on the qualitative understanding of the physics rather than the, at times somewhat tedious, formal derivations

Nuclear reactor for release of nuclear energy, without a chain reaction using the simultaneous implosion of three, or more, atomic nuclei

International Nuclear Information System (INIS)

Pedrick, A.P.

1976-01-01

A modified form of what is known as a 'streaking nuclear reactor' is described. In this type of reactor it is proposed to obtain release of nuclear energy from atomic nuclei by stripping such nuclei of their electron clouds or shells, to form a high temperature plasma, and breaking nucleons off the surface of the nuclei. In the apparatus described it is proposed to break up nuclei by causing three or more nuclei to collide with each other at very high velocity. Streams of nuclei, stripped of their electron clouds are directed into a reactor vessel to a focal point or implosion center along three or more ducts, equi-angularly spaced around the implosion center in the same plane, the arrangement being such as to permit mutual simultaneous collision of three or more of the nuclei. The importance of achieving a release of nuclear energy in this manner is that it may be able to use any chemical element that can be converted to a plasma, but it is most likely to be successful with elements of high atomic number, such as Pb or Bi. (U.K.)

The CCONE Code System and its Application to Nuclear Data Evaluation for Fission and Other Reactions

Science.gov (United States)

Iwamoto, O.; Iwamoto, N.; Kunieda, S.; Minato, F.; Shibata, K.

2016-01-01

A computer code system, CCONE, was developed for nuclear data evaluation within the JENDL project. The CCONE code system integrates various nuclear reaction models needed to describe nucleon, light charged nuclei up to alpha-particle and photon induced reactions. The code is written in the C++ programming language using an object-oriented technology. At first, it was applied to neutron-induced reaction data on actinides, which were compiled into JENDL Actinide File 2008 and JENDL-4.0. It has been extensively used in various nuclear data evaluations for both actinide and non-actinide nuclei. The CCONE code has been upgraded to nuclear data evaluation at higher incident energies for neutron-, proton-, and photon-induced reactions. It was also used for estimating β-delayed neutron emission. This paper describes the CCONE code system indicating the concept and design of coding and inputs. Details of the formulation for modelings of the direct, pre-equilibrium and compound reactions are presented. Applications to the nuclear data evaluations such as neutron-induced reactions on actinides and medium-heavy nuclei, high-energy nucleon-induced reactions, photonuclear reaction and β-delayed neutron emission are mentioned.

The CCONE Code System and its Application to Nuclear Data Evaluation for Fission and Other Reactions

Energy Technology Data Exchange (ETDEWEB)

Iwamoto, O., E-mail: iwamoto.osamu@jaea.go.jp; Iwamoto, N.; Kunieda, S.; Minato, F.; Shibata, K.

2016-01-15

A computer code system, CCONE, was developed for nuclear data evaluation within the JENDL project. The CCONE code system integrates various nuclear reaction models needed to describe nucleon, light charged nuclei up to alpha-particle and photon induced reactions. The code is written in the C++ programming language using an object-oriented technology. At first, it was applied to neutron-induced reaction data on actinides, which were compiled into JENDL Actinide File 2008 and JENDL-4.0. It has been extensively used in various nuclear data evaluations for both actinide and non-actinide nuclei. The CCONE code has been upgraded to nuclear data evaluation at higher incident energies for neutron-, proton-, and photon-induced reactions. It was also used for estimating β-delayed neutron emission. This paper describes the CCONE code system indicating the concept and design of coding and inputs. Details of the formulation for modelings of the direct, pre-equilibrium and compound reactions are presented. Applications to the nuclear data evaluations such as neutron-induced reactions on actinides and medium-heavy nuclei, high-energy nucleon-induced reactions, photonuclear reaction and β-delayed neutron emission are mentioned.

Experiment E89-044 on the Quasielastic ³He(e,e'p) Reaction at Jefferson Laboratory

Energy Technology Data Exchange (ETDEWEB)

Penel-Nottaris, Emilie [Univ. Joseph Fourier Grenoble (France)

2004-07-07

The Jefferson Lab Hall A E89-044 experiment has measured the ³He(e,e'p) reaction cross-sections. The extraction of the longitudinal and transverse response functions for the two-body break-up ³He(e,e'p)d reaction in parallel kinematics allows the study of the bound proton electromagnetic properties inside the ³He nucleus and the involved nuclear mechanisms beyond plane wave approximations.

Progress Report, Nuclear Reaction Data Group at ATOMKI (NRDC Meeting, 16-19 April 2012)

International Nuclear Information System (INIS)

Tarkanyi, F.; Takacs, S.; Ditroi, F.; Szelecsenyi, F.; Kovacs, Z.; Szucs, Z.; Kiraly, B.; Csikai, J.

2012-01-01

The research program of the Atomki Nuclear Reaction Data Group consists of measurement, compilation, evaluation and application of low and medium energy charged particle induced nuclear reaction data. The work is done in international collaborations. The experiments, data compilation and data evaluation are mainly connected to running international projects. Every day applications at ATOMKI and collaborating institutes also initiate data measurements. One initiative is the systematic experimental study of activation cross sections of proton and deuteron induced reactions for comparison with the results of modern theoretical codes to establish a more reliable experimental database and to prepare of a general use activation file up to 100 MeV protons and 50 MeV deuterons. Second program is the systematic investigation of nuclear data for production of radioisotopes candidate for use in radiotherapy. The staff members are active referrers of different journals and conference proceedings reporting nuclear data related works (Applied Radiation and Isotopes, Journal of Radioanalytical and nuclear Chemistry, Nuclear Instruments and Methods, Annals of Nuclear Energy, etc)

Theoretical studies in nuclear reactions and nuclear structure

International Nuclear Information System (INIS)

1992-05-01

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. Hadrons in nuclear matter; the structure of hadrons; relativistic nuclear physics and heavy ion dynamics and related processes. The section on hadrons in nuclear matter groups together research items which are aimed at exploring ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. A very interesting result has been the finding that QCD sum rules supply a new insight into the decrease of the nucleon's mass in the nuclear medium. The quark condensate, which characterizes spontaneous chiral symmetry breaking of the late QCD vacuum, decreases in nuclear matter and this is responsible for the decrease of the nucleon's mass. The section on the structure of hadrons contains progress reports on our research aimed at understanding the structure of the nucleon. Widely different approaches are being studied, e.g., lattice gauge calculations, QCD sum rules, quark-meson models with confinement and other hedgehog models. A major goal of this type of research is to develop appropriate links between nuclear physics and QCD. The section on relativistic nuclear physics represents our continuing interest in developing an appropriate relativistic framework for nuclear dynamics. A Lorentz-invariant description of the nuclear force suggests a similar decrease of the nucleon's mass in the nuclear medium as has been found from QCD sum rules. Work in progress extends previous successes in elastic scattering to inelastic scattering of protons by nuclei. The section on heavy ion dynamics and related processes reports on research into the e + e - problem and heavy ion dynamics

Extension of the energy range of the experimental activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium up to 65MeV.

Science.gov (United States)

Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

2015-04-01

Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65MeV by using stacked foil irradiation and gamma spectrometry experimental methods. Experimental cross-sections data for the formation of the radionuclides (159)Dy, (157)Dy, (155)Dy, (161)Tb, (160)Tb, (156)Tb, (155)Tb, (154m2)Tb, (154m1)Tb, (154g)Tb, (153)Tb, (152)Tb and (151)Tb are reported in the 36-65MeV energy range, and compared with an old dataset from 1964. The experimental data were also compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS nuclear reaction model code as listed in the latest on-line libraries TENDL 2013. Copyright © 2015. Published by Elsevier Ltd.

EMPIRE-II statistical model code for nuclear reaction calculations

Energy Technology Data Exchange (ETDEWEB)

Herman, M [International Atomic Energy Agency, Vienna (Austria)

2001-12-15

EMPIRE II is a nuclear reaction code, comprising various nuclear models, and designed for calculations in the broad range of energies and incident particles. A projectile can be any nucleon or Heavy Ion. The energy range starts just above the resonance region, in the case of neutron projectile, and extends up to few hundreds of MeV for Heavy Ion induced reactions. The code accounts for the major nuclear reaction mechanisms, such as optical model (SCATB), Multistep Direct (ORION + TRISTAN), NVWY Multistep Compound, and the full featured Hauser-Feshbach model. Heavy Ion fusion cross section can be calculated within the simplified coupled channels approach (CCFUS). A comprehensive library of input parameters covers nuclear masses, optical model parameters, ground state deformations, discrete levels and decay schemes, level densities, fission barriers (BARFIT), moments of inertia (MOMFIT), and {gamma}-ray strength functions. Effects of the dynamic deformation of a fast rotating nucleus can be taken into account in the calculations. The results can be converted into the ENDF-VI format using the accompanying code EMPEND. The package contains the full EXFOR library of experimental data. Relevant EXFOR entries are automatically retrieved during the calculations. Plots comparing experimental results with the calculated ones can be produced using X4TOC4 and PLOTC4 codes linked to the rest of the system through bash-shell (UNIX) scripts. The graphic user interface written in Tcl/Tk is provided. (author)

Fragmentation processes in nuclear reactions

International Nuclear Information System (INIS)

Legrain, R.

1984-08-01

Projectile and nuclear fragmentation are defined and processes referred to are recalled. The two different aspects of fragmentation are considered but the emphasis is also put on heavy ion induced reactions. The preliminary results of an experiment performed at GANIL to study peripheral heavy ions induced reactions at intermediate energy are presented. The results of this experiment will illustrate the characteristics of projectile fragmentation and this will also give the opportunity to study projectile fragmentation in the transition region. Then nuclear fragmentation is considered which is associated with more central collisions in the case of heavy ion induced reactions. This aspect of fragmentation is also ilustrated with two heavy ion experiments in which fragments emitted at large angle have been observed

Experimental investigation of hysteresis in the break-up of liquid curtains

KAUST Repository

Marston, Jeremy; Thoroddsen, Sigurdur T; Thompson, John W.; Blyth, Mark G.; Henry, Daniel; Uddin, Jamal

2014-01-01

Findings from an experimental investigation of the break-up of liquid curtains are reported, with the overall aim of examining stability windows for multi-layer liquid curtains composed of Newtonian fluids, where the properties of each layer can

Nuclear theory progress report, April 1991--April 1992

International Nuclear Information System (INIS)

1992-01-01

This report discusses research in nuclear theory on the following topics: nuclear astrophysics; quantum chromodynamics; quark matter; symmetry breaking; heavy ion reactions; hadronic form factors; neutrino processes; nuclear structure; weak interaction physics; and other related topics

Nuclear reactions in astrophysics

International Nuclear Information System (INIS)

Cardenas, M.

1976-01-01

It is revised the nuclear reactions which present an interest in astrophysics regarding the explanation of some problems such as the relative quantity of the elements, the structure and evolution of the stars. The principal object of the study is the determination of the experimental possibilities in the field of astrophysics, of an accelerator Van de Graaff's 700 KeV type. Two hundred nuclear reactions approximately, were found, and nothing or very little has been done in the intervals of energy which are of interest. Since the bombardment energies and the involved sections are low in some cases, there are real possibilities, for the largest number of stars to obtain important statistical data with the above mentioned accelerator, taking some necessary precautions. (author)

Ion beam analysis - development and application of nuclear reaction analysis methods, in particular at a nuclear microprobe

International Nuclear Information System (INIS)

Sjoeland, K.A.

1996-11-01

This thesis treats the development of Ion Beam Analysis methods, principally for the analysis of light elements at a nuclear microprobe. The light elements in this context are defined as having an atomic number less than approx. 13. The work reported is to a large extent based on multiparameter methods. Several signals are recorded simultaneously, and the data can be effectively analyzed to reveal structures that can not be observed through one-parameter collection. The different techniques are combined in a new set-up at the Lund Nuclear Microprobe. The various detectors for reaction products are arranged in such a way that they can be used for the simultaneous analysis of hydrogen, lithium, boron and fluorine together with traditional PIXE analysis and Scanning Transmission Ion Microscopy as well as photon-tagged Nuclear Reaction Analysis. 48 refs

Modeling of bubble break-up in stirred tanks

Directory of Open Access Journals (Sweden)

Živković Goran

2004-01-01

Full Text Available The Lagrangian code LAG3D for dispersed phase flow modeling was implemented with the introduction of bubble break-up model. The research was restricted on bubbles with diameter less than 2 mm, i.e. bubbles which could be treated as spheres. The model was developed according to the approach of Martinez-Bazan model. It was rearranged and adjusted for the use in the particular problem of flow in stirred tanks. Developed model is stochastic one, based on the assumption that shear in the flow induces the break of the bubble. As a dominant parameter a dissipation of the turbulent kinetic energy was used. Computations were performed for two different types of the stirrer: Rushton turbine, and Pitch blade turbine. The geometry of the tank was kept constant (four blades. Two different types of liquids with very big difference in viscosity were used, i.e. silicon oil and dimethylsulfoxide, in order to enable computation of the flow in turbulent regime as well. As a parameter of the flow, the number of rotations of the stirrer was varying. As a result of the computation the fields of velocity of both phases were got, as well as the fields of bubble concentration bubble mean diameter and bubble Sauter diameter. To estimate the influence of the break-up model on the processes in the stirred tank a computations with and without this model were performed and compared. A considerable differences were found not only in the field of bubble diameter, but also in the field of bubble concentration. That confirmed a necessity of the introduction of such model. A comparison with the experiments performed with phase Doppler anemometry technique showed very good agreement in velocity and concentration profiles of the gas phase. The results for the average bubble diameter are qualitatively the same, but in almost all computations about 20% smaller bubble diameter was got than in the measurements.

Nuclear reactions in ultra-magnetized supernovae

International Nuclear Information System (INIS)

Kondratyev, V.N.

2002-06-01

The statistical model is employed to investigate nuclear reactions in ultrastrong magnetic fields relevant for supernovae and neutron stars. For radiative capture processes the predominant mechanisms are argued to correspond to modifications of nuclear level densities, and γ-transition energies due to interactions of the field with magnetic moments of nuclei. The density of states reflects the nuclear structure and results in oscillations of reaction cross sections as a function of field strength, while magnetic interaction energy enhances radiative neutron capture process. Implications in the synthesis of r-process nuclei in supernova site are discussed. (author)

Di-nuclear systems studied with the velocity filter SHIP

Energy Technology Data Exchange (ETDEWEB)

Heinz, S.; Hessberger, F.P.; Ackermann, D.; Burkhard, H.G.; Khuyagbaatar, J.; Kindler, B.; Lommel, B.; Mann, R.; Maurer, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Comas, V.; Heredia, J. [Institute of Technologies and Applied Sciences, Habana (Cuba); Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Gan, Z. [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Nishio, K. [Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki (Japan); Sulignano, B. [DAPNIA / SPhN, CEA Saclay, Gif-sur-Yvette Cedex (France)

2008-11-15

Various nuclear reactions like quasi-fission, fusion-fission or particle and cluster evaporation from excited compound nuclei were studied in heavy-ion reactions at the velocity filter SHIP of GSI. The velocity filter offers the possibility to detect all reaction products under zero degree relative to the beam direction. Together with the measurement of the product velocity distribution this allows for an identification of the underlying reaction mechanism. This article is focussed on reactions of {sup 25}Mg and {sup 64}Ni beams on {sup 206,207}Pb targets at energies of 5.9 x A MeV and 8.7 x A MeV. Besides evaporation residues from {sup 25}Mg+{sup 206}Pb collisions we found evidence for rotation and quasi-fission of nuclear molecules formed in the entrance channel after the capture stage. The break-up of the systems showed a preferred clustering leading to isotopes in the region 84{<=}Z{<=}88 and 122{<=}N{<=}127 of the chart of nuclei. (orig.)

Nuclear chain reaction: forty years later

International Nuclear Information System (INIS)

Sachs, R.G.

1984-01-01

The proceedings from a 1982 symposium 40 years after the first controlled nuclear chain reaction took place in Chicago covers four sessions and public discussion. The session covered the history of the chain reaction; peaceful uses in technology, medicine, and biological science; peaceful uses in power generation; and nuclear weapons control. Among the speakers were Eugene Wigner, Glenn Seaborg, Alvin Weinberg, and others who participated in the first chain reaction experiments. The proceedings reflect differences of opinion among the scientists as well as the general public. References, slides, and tables used to illustrate the individual talks are included with the papers

Significance of Alkali-Silica reaction in nuclear safety-related concrete structures

International Nuclear Information System (INIS)

Le Pape, Y.; Field, K.G.; Mattus, C.H.; Naus, D.J.; Busby, J.T.; Saouma, V.; Ma, Z.J.; Cabage, J.V.; Guimaraes, M.

2015-01-01

Nuclear Power Plant license renewal up to 60 years and possible life extension beyond has established a renewed focus on long-term aging of nuclear generating stations materials, and particularly, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete components. The Expanded Materials Degradation Analysis, jointly performed by the Department of Energy, the U.S. Nuclear Regulatory Commission, the Academia and the Power Generation Industry, identified the need to develop a consistent knowledge base of alkali-silica reaction (ASR) within concrete as an urgent priority (Graves et al., 2014). ASR results in an expansion of Concrete produced by the reaction between alkali (generally from cement), reactive aggregate (like amorphous silica) and water absorption. ASR causes expansion, cracking and loss of mechanical properties. Considering that US commercial reactors in operation enter the age when ASR distress can be potentially observed and that numerous non-nuclear infrastructures (transportation, energy production) in a majority of the States have already experienced ASR-related concrete degradation, the susceptibility and significance of ASR for nuclear concrete structures must be addressed. This paper outlines an on-going research program including the investigation of the possibility of ASR in nuclear power plants, and the assessment of the residual shear bearing capacity of ASR-subjected nuclear structures. (authors)

Charge symmetry breaking in the dd → {sup 4}Heπ{sup 0} reaction with WASA-at-COSY

Energy Technology Data Exchange (ETDEWEB)

Zurek, Maria [Forschungszentrum Juelich, Juelich (Germany); Collaboration: WASA-at-COSY-Collaboration

2015-07-01

Investigations of charge symmetry breaking is one of the key topics for the WASA-at-COSY experiment. The study concentrates on the charge symmetry forbidden dd → {sup 4}Heπ{sup 0} reaction. The aim is to compare the experimental results with Chiral Perturbation Theory predictions, probing hadronic effects of the up and down quarks mass difference. It was found that previous data taken close to the reaction threshold were consistent with s-wave. In order to probe also p-wave contributions, new data at sufficiently high energy were required. The measurement should comprise the charge symmetry forbidden dd → {sup 4}Heπ{sup 0} reaction and the charge symmetry conserving reaction dd → {sup 3}Henπ{sup 0} to provide additionally the experimental input for the description of the initial state interactions. Results on the dd → {sup 3}Henπ{sup 0} and dd → {sup 4}Heπ{sup 0} reactions with the WASA detector setup at a beam momentum of 1.2 GeV/c are presented. In addition, the status of the recent high statistics run in spring 2014 is discussed.

SkyNet: A Modular Nuclear Reaction Network Library

Science.gov (United States)

Lippuner, Jonas; Roberts, Luke F.

2017-12-01

Almost all of the elements heavier than hydrogen that are present in our solar system were produced by nuclear burning processes either in the early universe or at some point in the life cycle of stars. In all of these environments, there are dozens to thousands of nuclear species that interact with each other to produce successively heavier elements. In this paper, we present SkyNet, a new general-purpose nuclear reaction network that evolves the abundances of nuclear species under the influence of nuclear reactions. SkyNet can be used to compute the nucleosynthesis evolution in all astrophysical scenarios where nucleosynthesis occurs. SkyNet is free and open source, and aims to be easy to use and flexible. Any list of isotopes can be evolved, and SkyNet supports different types of nuclear reactions. SkyNet is modular so that new or existing physics, like nuclear reactions or equations of state, can easily be added or modified. Here, we present in detail the physics implemented in SkyNet with a focus on a self-consistent transition to and from nuclear statistical equilibrium to non-equilibrium nuclear burning, our implementation of electron screening, and coupling of the network to an equation of state. We also present comprehensive code tests and comparisons with existing nuclear reaction networks. We find that SkyNet agrees with published results and other codes to an accuracy of a few percent. Discrepancies, where they exist, can be traced to differences in the physics implementations.

A method of simulating and visualizing nuclear reactions

International Nuclear Information System (INIS)

Atwood, C.H.; Paul, K.M.

1994-01-01

Teaching nuclear reactions to students is difficult because the mechanisms are complex and directly visualizing them is impossible. As a teaching tool, the authors have developed a method of simulating nuclear reactions using colliding water droplets. Videotaping of the collisions, taken with a high shutter speed camera and run frame-by-frame, shows details of the collisions that are analogous to nuclear reactions. The method for colliding the water drops and videotaping the collisions are shown

Nuclear phenomena in low-energy nuclear reaction research.

Science.gov (United States)

Krivit, Steven B

2013-09-01

This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.

Theoretical studies in nuclear reactions and nuclear structure

Energy Technology Data Exchange (ETDEWEB)

1992-05-01

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. Hadrons in nuclear matter; the structure of hadrons; relativistic nuclear physics and heavy ion dynamics and related processes. The section on hadrons in nuclear matter groups together research items which are aimed at exploring ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. A very interesting result has been the finding that QCD sum rules supply a new insight into the decrease of the nucleon's mass in the nuclear medium. The quark condensate, which characterizes spontaneous chiral symmetry breaking of the late QCD vacuum, decreases in nuclear matter and this is responsible for the decrease of the nucleon's mass. The section on the structure of hadrons contains progress reports on our research aimed at understanding the structure of the nucleon. Widely different approaches are being studied, e.g., lattice gauge calculations, QCD sum rules, quark-meson models with confinement and other hedgehog models. A major goal of this type of research is to develop appropriate links between nuclear physics and QCD. The section on relativistic nuclear physics represents our continuing interest in developing an appropriate relativistic framework for nuclear dynamics. A Lorentz-invariant description of the nuclear force suggests a similar decrease of the nucleon's mass in the nuclear medium as has been found from QCD sum rules. Work in progress extends previous successes in elastic scattering to inelastic scattering of protons by nuclei. The section on heavy ion dynamics and related processes reports on research into the e{sup +}e{sup {minus}} problem and heavy ion dynamics.

Nuclear alignment following compound nucleus reactions

International Nuclear Information System (INIS)

Butler, P.A.; Nolan, P.J.

1981-01-01

A procedure for calculating the alignment of a nuclear state populated by a compound nucleus reaction is given and used to investigate how alignment varies for different types of population mechanisms. The calculations are compared to both predictions of Gaussian models for the state population distribution and to experimental data, for a variety of types of nuclear reactions. The treatment of alignment in the analysis of γ-ray angular distribution is discussed. (orig.)

Applications of a superconducting solenoidal separator in the experimental investigation of nuclear reactions

International Nuclear Information System (INIS)

Hinde, D J; Carter, I P; Dasgupta, M; Simpson, E C; Cook, K J; Kalkal, Sunil; Luong, D H; Williams, E

2017-01-01

This paper describes applications of a novel superconducting solenoidal separator, with magnetic fields up to 8 Tesla, for studies of nuclear reactions using the Heavy Ion Accelerator Facility at the Australian National University. (paper)

Aerosol cluster impact and break-up: model and implementation

International Nuclear Information System (INIS)

Lechman, Jeremy B.

2010-01-01

In this report a model for simulating aerosol cluster impact with rigid walls is presented. The model is based on JKR adhesion theory and is implemented as an enhancement to the granular (DEM) package within the LAMMPS code. The theory behind the model is outlined and preliminary results are shown. Modeling the interactions of small particles is relevant to a number of applications (e.g., soils, powders, colloidal suspensions, etc.). Modeling the behavior of aerosol particles during agglomeration and cluster dynamics upon impact with a wall is of particular interest. In this report we describe preliminary efforts to develop and implement physical models for aerosol particle interactions. Future work will consist of deploying these models to simulate aerosol cluster behavior upon impact with a rigid wall for the purpose of developing relationships for impact speed and probability of stick/bounce/break-up as well as to assess the distribution of cluster sizes if break-up occurs. These relationships will be developed consistent with the need for inputs into system-level codes. Section 2 gives background and details on the physical model as well as implementations issues. Section 3 presents some preliminary results which lead to discussion in Section 4 of future plans.

Study of subnuclear degrees of freedom in electromagnetic break-up of the deuteron

International Nuclear Information System (INIS)

Arenhoevel, H.

1991-01-01

The role of subnuclear degrees of freedom in terms of meson and isobar degrees of freedom is discussed for the simplest process in nuclear physics, i.e., the electromagnetic break-up of the deuteron. The various theoretical schemes for incorporating such degrees of freedom either explicitly or as effective operators are briefly reviewed. The principle of minimal substitution as a means to construct effective two-body exchange current operators is illustrated and explicit expressions for pion exchange are given. The cross sections for photo- and electrodisintegration of the deuteron are expressed in terms of the t-matrix elements. The different theoretical methods for the calculation of the t-matrix are described and the essential ingredients for the non-relativistic evaluation including the most important relativistic corrections of lowest order are outlined. For specific experiments in photo- and electrodisintegration theoretical results are compared to experimental data and the present status of our understanding of these processes in assessed. (author). Refs, figs

Theoretical studies in nuclear reaction and nuclear structure. Final report, January 1, 1975--June 30, 1976

International Nuclear Information System (INIS)

Banerjee, M.K.; Griffin, J.J.

1977-07-01

Progress in theoretical research is reported under the following readings: (1) few nuclear reactions, Eikonal approximations, and optical models; (2) pion reactions; (3) nuclear structure by reaction studies; (4) nuclear dynamics

Nuclear reactions with radioactive and stable beams (Part I); Reacciones nucleares con haces radiactivos y estables (Parte I)

Energy Technology Data Exchange (ETDEWEB)

Aguilera R, E.F.; Martinez Q, E.; Gomez C, A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2004-12-15

At the present time there is a great interest at world level in experiments, with accelerated nuclei of short half life. The dispersion, fusion, transfer and break processes in the interaction of weakly light projectiles bounded with targets of Z great its have been object of intense recent investigation, at world level. Our group, in collaboration with the University of Notre Dame, it has measured and analyzed these processes for weakly bound systems as: {sup 6}He + {sup 209}Bi, {sup 8}Li + {sup 208}Pb, {sup 10}Be + {sup 208}Pb. On the other hand a research line that has wakened up great interest, it is that of studies of resonant reactions using the Inverse Kinematics technique with thick targets. The use of this technique allows to measure an entire excitation function with a single bombardment. Our group has carried out, in the ININ, preliminary bombardments for the system {sup 12}C + {sup 4}He. This allowed to establish the feasibility of implementing this technique in our Laboratory. The application of this and other techniques to different systems like {sup 18}O + {sup 4}He, {sup 12}C + {sup 12}C, {sup 12}C + {sup 16}O, {sup 16}O + {sup 16}O, it opens the possibility to measure the fusion of these systems at very low energy and to deepen in the knowledge of the nuclear structure and the nuclear astrophysics. In this technical report, the activities carried out by our group during 2004 are described.(Author)

NMTC/JAM, Simulates High Energy Nuclear Reactions and Nuclear-Meson Transport Processes

International Nuclear Information System (INIS)

Furihata, Shiori

2002-01-01

1 - Description of program or function: NMTC/JAM is an upgraded version of the code system NMTC/JAERI97. NMTC/JAERI97 simulates high energy nuclear reactions and nucleon-meson transport processes. It implements an intra-nuclear cascade model taking account of the in-medium nuclear effects and the pre-equilibrium calculation model based on the exciton one. For treating the nucleon transport process, the nucleon-nucleus cross sections are revised to those derived by the systematics of Pearlstein. Moreover, the level density parameter derived by Ignatyuk is included as a new option for particle evaporation calculation. A geometry package based on the Combinatorial Geometry with multi-array system and the importance sampling technique is implemented in the code. Tally function is also employed for obtaining such physical quantities as neutron energy spectra, heat deposition and nuclide yield without editing a history file. The code can simulate both the primary spallation reaction and the secondary particle transport in the intermediate energy region from 20 MeV to 3.5 GeV by the use of the Monte Carlo technique. The code has been employed in combination with the neutron-photon transport codes available to the energy region below 20 MeV for neutronics calculation of accelerator-based subcritical reactors, analyses of thick target spallation experimented and so on. 2 - Methods: High energy nuclear reactions induced by incident high energy protons, neutrons and pions are simulated with the Monte Carlo Method by the intra-nuclear nucleon-nucleon reaction probabilities based on an intra-nuclear nucleon cascade model followed by the particle evaporation including high energy fission process. Jet-Aa Microscopic transport model (JAM) is employed to simulate high energy nuclear reactions in the energy range of GeV. All reaction channels are taken into account in the JAM calculation. An intra-nuclear cascade model (ISOBAR code) taking account of the in-medium nuclear effects

Macroscopic/microscopic simulation of nuclear reactions at intermediate energies

International Nuclear Information System (INIS)

Lacroix, D.; Van Lauwe, A.; Durand, D.

2003-01-01

An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the description of nuclear collisions in the intermediate energy range is presented. The model simulates events for reactions close to the fusion barrier (5-10 MeV/A) up to higher energy (100 MeV/A) and it gives access to the phase-space explored during the collision. The development of HIPSE has been largely influenced by experimental observations. We have separated the reaction into 4 steps: contact, fragment formation, chemical freeze-out, and in-flight deexcitation. HIPSE will be useful for a study of various mechanisms such as neck fragmentation or multi-fragmentation

Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects

International Nuclear Information System (INIS)

Chen Yu; Jiang Bingyao; Chen Youshan; Ding Xingzhao; Liu Xianghuai; Chen Ceshi; Guo Xinyou; Yin Guanglin

1998-01-01

Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1 x 10 12 ions/cm 2 . The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed. (orig.)

Effect of nuclear reaction rates on primordial abundances

International Nuclear Information System (INIS)

Mishra, Abhishek; Basu, D.N.

2011-01-01

The theoretical predictions of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction rates. The effect of modifying these reaction rates on light element abundance yields in BBN by replacing the thirty-five reaction rates out of the existing eighty-eight has been investigated. Also the study have been taken of these yields as functions of evolution time or temperature. Here it has been found that using these new reaction rates results in only a little increase in helium mass fraction over that obtained previously in BBN calculations. This allows insights into the role of the nuclear reaction rates in the setting of the neutron-to-proton ratio during the BBN epoch. We observe that most of these nuclear reactions have minimal effect on the standard BBN abundance yields of 6 Li and 7 Li

Induced isospin mixing in direct nuclear reactions

International Nuclear Information System (INIS)

Lenske, H.

1979-07-01

The effect of charge-dependent interactions on nuclear reactions is investigated. First, a survey is given on the most important results concerning the charge dependence of the nucleon-nucleon interaction. The isospin symmetry and invariance principles are discussed. Violations of the isospin symmetry occuring in direct nuclear reactions are analysed using the soupled channel theory, the folding model and microscopic descriptions. Finally, induced isospin mixing in isospin-forbidden direct reactions is considered using the example of the inelastic scattering of deuterons on 12 C. (KBE)

Extension of the energy range of experimental activation cross-sections data of deuteron induced nuclear reactions on indium up to 50MeV.

Science.gov (United States)

Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

2015-11-01

The energy range of our earlier measured activation cross-sections data of longer-lived products of deuteron induced nuclear reactions on indium were extended from 40MeV up to 50MeV. The traditional stacked foil irradiation technique and non-destructive gamma spectrometry were used. No experimental data were found in literature for this higher energy range. Experimental cross-sections for the formation of the radionuclides (113,110)Sn, (116m,115m,114m,113m,111,110g,109)In and (115)Cd are reported in the 37-50MeV energy range, for production of (110)Sn and (110g,109)In these are the first measurements ever. The experimental data were compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS 1.6 nuclear model code as listed in the on-line library TENDL-2014. Copyright © 2015 Elsevier Ltd. All rights reserved.

Report of seminar on relativistic approach to nuclear reaction and nuclear structure

International Nuclear Information System (INIS)

1986-05-01

A seminar on 'Relativistic Approach to Nuclear Reaction and Nuclear Structure' was held in 1985 at Osaka University. This booklet includes twenty-four reports given at the seminar, which deal with: Conventional Nonrelativistic Description of Nuclear Matter and Nuclear Spin-Orbit Interactions; Relativistic Approach to Nuclear Structure; Atomic and Molecular Structure Calculations; Electromagnetic Interaction in Nucleus and Relativistic Effect; Nuclear Magnetic Moment in the Relativistic Mean Field Theory, Effective Mass and Particle-Vibration Coupling in the Relativistic σ-ω Model; Gauge Invariance in Relativistic Many-Body Theory; Relativistic Description of Nucleon-Nucleon Interaction in Review; σ-Particle in NN Interaction; Nuclear Optical Potentials Based on the Brueckner-Hartree-Fock Approach; Elastic Backscattering and Optical Potential; Description of Intermediate-Energy Nuclear Reactions; Dirac Phenomenology at E(p) = 65 MeV; Relativistic Impulse Approximation; Reaction Studies with Intermediate Energy Deuterons at SATURNE; Folding Model for Intermediate-Energy Deutron Scattering; Folding Model for Polarized Deutron Scattering at 700 MeV; Dirac Approach Problems and a Different Viewpoint; Relativistic Approach and EMC Effect; Quasielastic Electron Scattering; Response Function of Quasielastic Electron Scattering; Relativistic Hartree Response Function for Quasielastic Electron Scattering on 12 C and 40 Ca; Backflow-, Retardation- and Relativistic Effects on the Longitudinal Response Function of Nuclear Matter; Pion-Photoproduction in the σ-ω Model. (Nogami, K.)

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1993-01-01

This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in 82 Sr; structure of and identical bands in 182 Hg and 178 Pt; a highly deformed band in 136 Pm; particle decay of the 164 Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of 12 O; modeling and theoretical studies; excited 16 O disassembly into four alpha particles; 209 Bi + 136 Xe collisions at 28.2 MeV/amu; and development work on 4π solid angle gamma detectors, and x-ray detectors

Multilayer Network Analysis of Nuclear Reactions

Science.gov (United States)

Zhu, Liang; Ma, Yu-Gang; Chen, Qu; Han, Ding-Ding

2016-08-01

The nuclear reaction network is usually studied via precise calculation of differential equation sets, and much research interest has been focused on the characteristics of nuclides, such as half-life and size limit. In this paper, however, we adopt the methods from both multilayer and reaction networks, and obtain a distinctive view by mapping all the nuclear reactions in JINA REACLIB database into a directed network with 4 layers: neutron, proton, 4He and the remainder. The layer names correspond to reaction types decided by the currency particles consumed. This combined approach reveals that, in the remainder layer, the β-stability has high correlation with node degree difference and overlapping coefficient. Moreover, when reaction rates are considered as node strength, we find that, at lower temperatures, nuclide half-life scales reciprocally with its out-strength. The connection between physical properties and topological characteristics may help to explore the boundary of the nuclide chart.

Simulations of nuclear reactions for a future HIE-ISOLDE spectrometer

Energy Technology Data Exchange (ETDEWEB)

Tveten, Gry [University of Oslo (Norway); CERN (Switzerland); Cederkall, Joakim [Lund University (Sweden); CERN (Switzerland); Blumenfeld, Yorick [CERN (Switzerland)

2009-07-01

The planned High Intensity and Energy (HIE) upgrade of the radioactive beam facility ISOLDE will enable post-acceleration of radioactive beams up to an energy of about 10 MeV/u, thus opening the door to nuclear reaction studies. In the case of transfer reactions in inverse kinematics a recoil separator is often well suited or even needed to tell recoils and beam apart and to select the exit channel or to do spectroscopic studies. Two different types of spectrometer designs are being considered for HIE-ISOLDE, namely a recoil mass separator or a ray-tracing type of spectrometer. A set of nuclear transfer reactions in inverse kinematics have been simulated using realistic parameters for HIE-ISOLDE. The performance of the two types of spectrometer designs is compared and their scientific possibilities and limitations discussed based on the simulation results. To evaluate the validity of the simulations a data set from PRISMA at LNL is also compared with simulation results and a comparison between simulations and these data will be presented.

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1991-01-01

The research program of our group touches five areas of nuclear physics: (1) Nuclear structure studies at high spin; (2) Studies at the interface between structure and reactions; (3) Production and study of hot nuclei; (4) Incomplete fusion and fragmentation reactions; and (5) Development and use of novel techniques and instrumentation in the above areas of research. The papers from these areas are discussed in this report

Computational and experimental study of the effect of mass transfer on liquid jet break-up

Science.gov (United States)

Schetz, J. A.; Situ, M.

1983-06-01

A computational method has been developed to predict the effect of mass transfer on liquid jet break-up in coaxial, low velocity gas streams. Two conditions, both with and without the effect of mass transfer on the jet break-up, are calculated, and compared with experimental results and the classical linear theory. Methanol and water were used as the injectants. The numerical solution can predict the instantaneous shape of the jet surface and the break-up time, and it is very close to the experimental results. The numerical solutions and the experimental results both indicate that the wave number of the maximum instability is about 6.9, higher than 4.51 which was predicted by Rayleigh's linear theory. The experimental results and numerical solution show that the growth of the amplitude of the trough is faster than the growth of the amplitude of the crest, especially for a rapidly vaporizing jet. The numerical solutions show that for the small rates of evaporation, the effect of the mass transfer on the interface has a stabilizing effect near the wave number for maximum instability. Inversely, it has a destabilizing effect far from the wave number for maximum instability. For rapid evaporation, the effect of the mass transfer always has a destabilizing effect and decreases the break-up time of the jet.

Experimental investigation of hysteresis in the break-up of liquid curtains

KAUST Repository

Marston, Jeremy

2014-09-01

Findings from an experimental investigation of the break-up of liquid curtains are reported, with the overall aim of examining stability windows for multi-layer liquid curtains composed of Newtonian fluids, where the properties of each layer can be kept constant or varied. For a single-layer curtain it is known that the minimum flow rate required for initial stability can be violated by carefully reducing the flow rate below this point, which defines a hysteresis region. However, when two or three layers are used to form a composite curtain, the hysteresis window can be considerably reduced depending on the experimental procedure used. Extensive quantitative measurements of this hysteresis region are provided alongside an examination of the influence of physical properties such as viscosity and surface tension. The origins of curtain break-up for two different geometries are analysed; first where the curtain width remains constant, pinned by straight edge guides; and second where the curtain is tapered by angled edge guides. For both cases, the rupture speed is measured, which appears to be consistent with the Taylor-Culick velocity. Observations of the typical linearly spaced jets which form after the break-up has transpired and the periodicity of these jets are compared to the Rayleigh-Taylor wavelength and previous experimental measurements. Furthermore, the curtain stability criterion originally developed by Brown (1961), summarised in terms of a Weber number, has recently been extended to multi-layer curtains by Dyson et al. (2009); thus this report provides the first experimental measurements which puts this to the test. Ultimately, it is found that only the most viscous and polymer-based liquids violate this criterion. © 2014 Elsevier Ltd.

Tranverse beam break up in a periodic linac

International Nuclear Information System (INIS)

Decker, G.; Wang, J.M.

1987-01-01

The problem of cumulative beam break up in a periodic linac for a general impedance is discussed, with the effects of acceleration included. The transverse equations of motion for a set of identical point like bunches moving along the length of the linac are cast into a simple form using a smooth approximation. This results in a working formula that is used to analyze beam breakup. Explicit expressions for the transverse motion in the case of a single resonance impedance are found using saddle point integration. This is done first with no external focusing, and again in the strong focusing limit

Laboratory approaches of nuclear reactions involved in primordial and stellar nucleosynthesis

International Nuclear Information System (INIS)

Rolfs, C.; California Inst. of Tech., Pasadena

1986-01-01

Laboratory-based studies of primordial and stellar nucleosynthesis are reviewed, with emphasis on the nuclear reactions induced by charged particles. The analytical approach used to investigate nuclear reactions associated with stellar reactions is described, as well as the experimental details and procedures used to investigate nuclear reactions induced by charged particles. The present knowledge of some of the key reactions involved in primordial nucleosynthesis is discussed, along with the progress and problems of nuclear reactions involved in the hydrogen and helium burning phases of a star. Finally, a description is given of new experimental techniques which might be useful for future experiments in the field of nuclear astrophysics. (U.K.)

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1990-01-01

This report discusses research in the following areas: nuclear structure; fusion reactions near and below the barrier; incomplete fusion and fragmentation reactions; and instrumentation and analysis. (LSP)

Identifying Understudied Nuclear Reactions by Text-mining the EXFOR Experimental Nuclear Reaction Library

Energy Technology Data Exchange (ETDEWEB)

Hirdt, J.A. [Department of Mathematics and Computer Science, St. Joseph' s College, Patchogue, NY 11772 (United States); Brown, D.A., E-mail: dbrown@bnl.gov [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

2016-01-15

The EXFOR library contains the largest collection of experimental nuclear reaction data available as well as the data's bibliographic information and experimental details. We text-mined the REACTION and MONITOR fields of the ENTRYs in the EXFOR library in order to identify understudied reactions and quantities. Using the results of the text-mining, we created an undirected graph from the EXFOR datasets with each graph node representing a single reaction and quantity and graph links representing the various types of connections between these reactions and quantities. This graph is an abstract representation of the connections in EXFOR, similar to graphs of social networks, authorship networks, etc. We use various graph theoretical tools to identify important yet understudied reactions and quantities in EXFOR. Although we identified a few cross sections relevant for shielding applications and isotope production, mostly we identified charged particle fluence monitor cross sections. As a side effect of this work, we learn that our abstract graph is typical of other real-world graphs.

Identifying Understudied Nuclear Reactions by Text-mining the EXFOR Experimental Nuclear Reaction Library

International Nuclear Information System (INIS)

Hirdt, J.A.; Brown, D.A.

2016-01-01

The EXFOR library contains the largest collection of experimental nuclear reaction data available as well as the data's bibliographic information and experimental details. We text-mined the REACTION and MONITOR fields of the ENTRYs in the EXFOR library in order to identify understudied reactions and quantities. Using the results of the text-mining, we created an undirected graph from the EXFOR datasets with each graph node representing a single reaction and quantity and graph links representing the various types of connections between these reactions and quantities. This graph is an abstract representation of the connections in EXFOR, similar to graphs of social networks, authorship networks, etc. We use various graph theoretical tools to identify important yet understudied reactions and quantities in EXFOR. Although we identified a few cross sections relevant for shielding applications and isotope production, mostly we identified charged particle fluence monitor cross sections. As a side effect of this work, we learn that our abstract graph is typical of other real-world graphs.

Breakup reactions at intermediate and high energy

International Nuclear Information System (INIS)

Shotter, A.C.; Bice, A.N.

1981-01-01

Having considered some general aspects of peripheral break-up reactions involving heavy ions for the incident energy range 10-2000 MeV/A, specific experiments carried out at Berkeley in 1980 in the energy range 10-20 MeV/A are discussed. These indicate that sequential break-up processes from non-sequential inelastic processes both play significant roles in the mechanism. (UK)

Effect of the long-term memory on the beam break-up instability of a single bunch in storage rings

International Nuclear Information System (INIS)

Pestrikov, D.V.

2009-01-01

We study modifications of the beam break-up instability of transverse coherent oscillations of a single bunch which occur in storage rings due to weak wakefields decaying longer than the revolution period of particles. The long-term part of the wake results in the eigenmode spectra of coherent oscillations. Both stable and unstable modes are found for coherent oscillations of a monochromatic bunch. The single turn wakefields result in the beam break-up coherent oscillations of the bunch. The found eigenmode spectrum does not contain a leading unstable mode. Despite the exponential increase in time of the eigenmodes, both self-consistent and the beam break-up parts of the coherent oscillations indicate similar and non-exponential time dependencies. The beam break-up behavior dominates, if the wake memory is weak.

Nuclear fission and reactions

International Nuclear Information System (INIS)

Anon.

1975-01-01

The nuclear fission research programs are designed to elucidate basic features of the fission process. Specifically, (1) factors determining how nucleons of a fissioning nucleus are distributed between two fission fragments, (2) factors determining kinetic energy and excitation energies of fragments, and (3) factors controlling fission lifetimes. To these ends, fission studies are reported for several heavy elements and include investigations of spontaneous and neutron-induced fission, heavy ion reactions, and high energy proton reactions. The status of theoretical research is also discussed. (U.S.)

Nuclear fuel burn-up economy

International Nuclear Information System (INIS)

Matausek, M.

1984-01-01

In the period 1981-1985, for the needs of Utility Organization, Beograd, and with the support of the Scientific Council of SR Srbija, work has been performed on the study entitled 'Nuclear Fuel Burn-up Economy'. The forst [phase, completed during the year 1983 comprised: comparative analysis of commercial NPP from the standpoint of nuclear fuel requirements; development of methods for fuel burn-up analysis; specification of elements concerning the nuclear fuel for the tender documentation. The present paper gives the short description of the purpose, content and results achieved in the up-to-now work on the study. (author)

Nuclear reactions and synthesis of new transuranium species

International Nuclear Information System (INIS)

Seaborg, G.T.

1983-01-01

In this short review, I shall describe the special aspects of heavy ion nuclear reaction mechanisms operative in the transuranium region, the role of new techniques, possible nuclear reactions for the production of additional transuranium elements and nuclear species and the importance of work in this region for the development of nuclear models and theoretical concepts. This discussion should make it clear that a continuing supply of leements and isotopes, some fo them relatively short-lived, produced by the HFIR-TRU facilities, will be a requirement for future synthesis of new elements and isotopes

Nuclear reactions with radioactive and stable beams (Part II)

International Nuclear Information System (INIS)

Aguilera R, E.F.; Martinez Q, E.; Gomez C, A.; Lizcano, D.

2005-12-01

At the present time there is a great interest at world level in experiments, with accelerated nuclei of short half life. The dispersion, fusion, transfer and break processes in the interaction of weakly light projectiles bounded with targets of Z great its have been object of intense recent investigation, at world level. Our group, in collaboration with the University of Notre Dame, it has measured and analyzed these processes for weakly bound systems as: 6 He + 209 Bi, 8 Li + 208 Pb, 10 Be + 208 Pb. On the other hand a research line that has wakened up great interest, it is that of studies of resonant reactions using the Inverse Kinematics technique with thick targets. The use of this technique allows to measure an entire excitation function with a single bombardment. Our group has carried out, in the ININ, preliminary bombardments for the system 12 C + 4 He. This allowed to establish the feasibility of implementing this technique in our Laboratory. The application of this and other techniques to different systems like 18 O + 4 He, 12 C + 12 C, 12 C + 16 O, 16 O + 16 O, it opens the possibility to measure the fusion of these systems at very low energy and to deepen in the knowledge of the nuclear structure and the nuclear astrophysics. In this technical report, the activities carried out by our group during the second stage of this project, considered for 2005 are described. Also in that year, our group carries out a research stay in the University of Notre Dame, during this stay, the angular distribution of the projectiles of 8 B dispersed in an enriched target of 58 Ni was measured. The same as in the previous experiments, in this occasion it was also possible to measure those angular distributions of the projectiles of 7 Be and 6 Li dispersed in this same target. In this same one our stay group participates in other three experiments proposed by collaborators of other institutions (University of Notre Dame, University of Sao Paulo), where the products of the

Improved predictions of nuclear reaction rates for astrophysics applications with the TALYS reaction code

International Nuclear Information System (INIS)

Goriely, S.; Hilaire, S.; Koning, A.J.

2008-01-01

Nuclear reaction rates for astrophysics applications are traditionally determined on the basis of Hauser-Feshbach reaction codes, like MOST. These codes use simplified schemes to calculate the capture reaction cross section on a given target nucleus, not only in its ground state but also on the different thermally populated states of the stellar plasma at a given temperature. Such schemes include a number of approximations that have never been tested, such as an approximate width fluctuation correction, the neglect of delayed particle emission during the electromagnetic decay cascade or the absence of the pre-equilibrium contribution at increasing incident energies. New developments have been brought to the reaction code TALYS to estimate the Maxwellian-averaged reaction rates of astrophysics relevance. These new developments give us the possibility to calculate with an improved accuracy the reaction cross sections and the corresponding astrophysics rates. The TALYS predictions for the thermonuclear rates of astrophysics relevance are presented and compared with those obtained with the MOST code on the basis of the same nuclear ingredients for nuclear structure properties, optical model potential, nuclear level densities and γ-ray strength. It is shown that, in particular, the pre-equilibrium process significantly influences the astrophysics rates of exotic neutron-rich nuclei. The reciprocity theorem traditionally used in astrophysics to determine photo-rates is also shown no to be valid for exotic nuclei. The predictions obtained with different nuclear inputs are also analyzed to provide an estimate of the theoretical uncertainties still affecting the reaction rate prediction far away from the experimentally known regions. (authors)

A comprehensive survey of nuclear reactions; Panorama des reactions nucleaires

Energy Technology Data Exchange (ETDEWEB)

Cugnon, J. [Liege Univ., IFPA, AGO Dept. (Belgium)

2007-07-01

The various mechanisms of nuclear reactions are surveyed and classified in different regimes, based on the notions of coherent mechanisms and hard versus soft processes. The emphasis is put on the concepts at the basis of the understanding of these regimes and on the elements of nuclear structure which are involved in these different regimes, as well as the on the possibility of extracting this information. Due to lack of space and for pedagogical reasons, the discussion is limited to nucleon-induced and light-ion-induced reactions. However, a few remarks are given concerning some specific probes, such as weakly bound projectiles or neutron-rich nuclei. (author)

Tear Film Break-Up Time: Comparison between Patients using Psychiatric Drugs and Healthy Individuals

Directory of Open Access Journals (Sweden)

Parvin Dibajnia

2014-09-01

Full Text Available Background: Ocular dryness is a well-recognized adverse side effect of many medications. The purpose of this study was to compare tear film stability between psychiatric patients that use lithium carbonate or carbamazepine and normal cases. Materials and Methods: Tear film break up time test was performed in three groups, 30 patients using lithium carbonate, 30 patients using carbamazepine and 30 normal cases. Values of the TBUTs were compared among groups by the independent t-test. Results: Differences between both of patients and control groups were significant (p<0.0001. Conclusion: The results show that these drugs contribute to decrease of tear film break up time.

The relation between invasive and non-invasive tear break-up time ...

African Journals Online (AJOL)

Tear stability normal to Nigerians with consideration of gender and age has not been reported. Tear stability in young adults was measured using invasive and non-invasive tear break-up time (TBUT and NIBUT). Forty –five subjects aged 20 to 30 years were selected from among the students of University of. Benin, Edo ...

Improved predictions of nuclear reaction rates with the TALYS reaction code for astrophysical applications

International Nuclear Information System (INIS)

Goriely, S.; Hilaire, S.; Koning, A.J

2008-01-01

Context. Nuclear reaction rates of astrophysical applications are traditionally determined on the basis of Hauser-Feshbach reaction codes. These codes adopt a number of approximations that have never been tested, such as a simplified width fluctuation correction, the neglect of delayed or multiple-particle emission during the electromagnetic decay cascade, or the absence of the pre-equilibrium contribution at increasing incident energies. Aims. The reaction code TALYS has been recently updated to estimate the Maxwellian-averaged reaction rates that are of astrophysical relevance. These new developments enable the reaction rates to be calculated with increased accuracy and reliability and the approximations of previous codes to be investigated. Methods. The TALYS predictions for the thermonuclear rates of relevance to astrophysics are detailed and compared with those derived by widely-used codes for the same nuclear ingredients. Results. It is shown that TALYS predictions may differ significantly from those of previous codes, in particular for nuclei for which no or little nuclear data is available. The pre-equilibrium process is shown to influence the astrophysics rates of exotic neutron-rich nuclei significantly. For the first time, the Maxwellian- averaged (n, 2n) reaction rate is calculated for all nuclei and its competition with the radiative capture rate is discussed. Conclusions. The TALYS code provides a new tool to estimate all nuclear reaction rates of relevance to astrophysics with improved accuracy and reliability. (authors)

The nuclear reaction matrix

International Nuclear Information System (INIS)

Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.; and Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794)

1976-01-01

Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the Aapprox. =18 region are performed following this procedure and treating the Pauli exclusion operator Q 2 /sub p/ by the method of Tsai and Kuo. The treatment of Q 2 /sub p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close agreement is obtained with the matrix elements calculated by Kuo and Brown using approximate methods

Shell and explosive hydrogen burning. Nuclear reaction rates for hydrogen burning in RGB, AGB and Novae

Energy Technology Data Exchange (ETDEWEB)

Boeltzig, A. [Gran Sasso Science Institute, L' Aquila (Italy); Bruno, C.G.; Davinson, T. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Cavanna, F.; Ferraro, F. [Dipartimento di Fisica, Universita di Genova (Italy); INFN, Genova (Italy); Cristallo, S. [Osservatorio Astronomico di Collurania, INAF, Teramo (Italy); INFN, Napoli (Italy); Depalo, R. [Dipartimento di Fisica e Astronomia, Universita di Padova, Padova (Italy); INFN, Padova (Italy); DeBoer, R.J.; Wiescher, M. [University of Notre Dame, Institute for Structure and Nuclear Astrophysics, Joint Institute for Nuclear Astrophysics, Notre Dame, Indiana (United States); Di Leva, A.; Imbriani, G. [Dipartimento di Fisica, Universita di Napoli Federico II, Napoli (Italy); INFN, Napoli (Italy); Marigo, P. [Dipartimento di Fisica e Astronomia, Universita di Padova, Padova (Italy); Terrasi, F. [Dipartimento di Matematica e Fisica Seconda Universita di Napoli, Caserta (Italy); INFN, Napoli (Italy)

2016-04-15

The nucleosynthesis of light elements, from helium up to silicon, mainly occurs in Red Giant and Asymptotic Giant Branch stars and Novae. The relative abundances of the synthesized nuclides critically depend on the rates of the nuclear processes involved, often through non-trivial reaction chains, combined with complex mixing mechanisms. In this paper, we summarize the contributions made by LUNA experiments in furthering our understanding of nuclear reaction rates necessary for modeling nucleosynthesis in AGB stars and Novae explosions. (orig.)

Time-reversal symmetry breaking in quantum billiards

Energy Technology Data Exchange (ETDEWEB)

Schaefer, Florian

2009-01-26

The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally

Time-reversal symmetry breaking in quantum billiards

International Nuclear Information System (INIS)

Schaefer, Florian

2009-01-01

The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally

The Flooding Water Source Analysis following the Feed Line Break at the Compartment outside Containment for Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Song, Dong Soo [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Park, Young Chan [ACT, Daejeon (Korea, Republic of)

2007-07-01

The Periodic Safety Review(PSR) has been performing for the operating nuclear power plant in Korea. One of the PSR evaluation items is environmental qualification. Flooding issue for nuclear power plants designed and built in 1970 is extremely severe for main steam header compartment and main feed water line region of intermediate building and lower floor. This study presents to analyze flood level of feed water line breaks for the Westinghouse nuclear power plant. This analyses provides the mass and energy releases using the developed methodology for a break outside containment. For the analyses RETRAN-3D computer program is used.

Nuclear reaction data for IBA applications to cultural heritage diagnostics

Energy Technology Data Exchange (ETDEWEB)

Maino, G.; Menapace, E. [Bologna Univ., ENEA (Italy)

2008-07-01

Main aspects are discussed concerning nuclear reaction cross-sections for PIXE and PIGE (Particle Induced Gamma-ray Emission) analyses, especially referring to cultural heritage diagnostics, within the framework of ion beam analysis (IBA) methods, also reviewing recent results from international Conferences on Nuclear Data for Science and Technology and from NEANSC meetings and IAEA initiatives on the matter.To sum up this work, it is then worth remarking the following items: IBA techniques are powerful tools to derive unique information as for corrosion, degradation and, generally, conservation conditions of materials. Careful analyses of specific systems require accurate evaluations and establishment of complete databases, in particular for stopping powers and relevant cross sections. The physical parameters to be accurately determined are, therefore, nuclear reaction cross sections of importance for NRA analysis of light elements and stopping powers and ranges of light and heavy ions in various matrices. Light elements (H, Li, B, C, N, O, etc.) play an important role as constituents of many important organic as well inorganic materials in historical and artistic objects. To a large extent these materials occur in the near-surface area of a material with altered or degraded composition.

Nuclear reaction data for IBA applications to cultural heritage diagnostics

International Nuclear Information System (INIS)

Maino, G.; Menapace, E.

2008-01-01

Main aspects are discussed concerning nuclear reaction cross-sections for PIXE and PIGE (Particle Induced Gamma-ray Emission) analyses, especially referring to cultural heritage diagnostics, within the framework of ion beam analysis (IBA) methods, also reviewing recent results from international Conferences on Nuclear Data for Science and Technology and from NEANSC meetings and IAEA initiatives on the matter.To sum up this work, it is then worth remarking the following items: IBA techniques are powerful tools to derive unique information as for corrosion, degradation and, generally, conservation conditions of materials. Careful analyses of specific systems require accurate evaluations and establishment of complete databases, in particular for stopping powers and relevant cross sections. The physical parameters to be accurately determined are, therefore, nuclear reaction cross sections of importance for NRA analysis of light elements and stopping powers and ranges of light and heavy ions in various matrices. Light elements (H, Li, B, C, N, O, etc.) play an important role as constituents of many important organic as well inorganic materials in historical and artistic objects. To a large extent these materials occur in the near-surface area of a material with altered or degraded composition

New methods in nuclear reaction theory

International Nuclear Information System (INIS)

Redish, E.F.

1979-01-01

Standard nuclear reaction methods are limited to treating problems that generalize two-body scattering. These are problems with only one continuous (vector) degree of freedom (CDOF). The difficulty in extending these methods to cases with two or more CDOFs is not just the additional numerical complexity: the mathematical problem is usually not well-posed. It is hard to guarantee that the proper boundary conditions (BCs) are satisfied. Since this is not generally known, the discussion is begun by considering the physics of this problem in the context of coupled-channel calculations. In practice, the difficulties are usually swept under the rug by the use of a highly developed phenomenology (or worse, by the failure to test a calculation for convergence). This approach limits the kind of reactions that can be handled to ones occurring on the surface of where a second CDOF can be treated perturbatively. In the past twenty years, the work of Faddeev, the quantum three-body problem has been solved. Many techniques (and codes) are now available for solving problems with two CDOFs. A method for using these techniques in the nuclear N-body problem is presented. A set of well-posed (connected kernal) equations for physical scattering operators is taken. Then it is shown how approximation schemes can be developed for a wide range of reaction mechanisms. The resulting general framework for a reaction theory can be applied to a number of nuclear problems. One result is a rigorous treatment of multistep transfer reactions with the possibility of systematically generating corrections. The application of the method to resonance reactions and knock-out is discussed. 12 figures

View of industry on the impact of pipe break criteria

International Nuclear Information System (INIS)

Bernsen, S.A.

1983-01-01

Historically, large pipe breaks in the types of materials used and under operating conditions similar to those in light water reactor service have not occurred. Nevertheless, the non-mechanistic assumption of a double ended pipe break of the early sixties, selected for loss of coolant accident analysis purposes, has become a mechanistic criterion for the design and arrangement of high pressure piping systems and their associated supports and enclosures in today's nuclear plants. While it seems reasonable and appropriate to continue to design the Emergency Core Cooling Systems for a range of loss of coolant accidents up to and including those that approximate the area of the largest pipe connected to the reactor vessel and to use this break in determining the loading and temperature rise rate for containment structures and equipment qualification, it no longer seems reasonable to provide precisely engineered break protection for a limited number of potential pipe break locations. This observation is gaining increasing support, particularly as engineering judgment and historical perspectives are being supplemented by both deterministic and probabilistic studies that indicate the potential for large instantaneous breaks in nuclear grade piping systems is virtually incredible. Fracture mechanics analyses support leak-before-break assumptions with wide margins and probabilistic studies indicate potentials for double-ended pipe breaks in the range of less than one in a billion years

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2003-01-01

Full text: In 2002, the Department has been involved in two new experimental programmes. Our colleagues led by Prof. Pawel Zupranski joined a large international collaboration HERMES and took part in experiments at DESY devoted to the study of the spin structure of the nucleon. Another group directed by Associate Prof. Bogdan Zwieglinski has worked on a conceptual design of a new generation detector PANDA (Proton-Antiproton Detection) which will be used in future experiments at GSI. Moreover, the experimental programmes covering three major domains of our scientific activities: nuclear physics, materials research and atomic physics were continued. - Nuclear physics: Experimental studies of nuclear reactions induced by heavy ions provided by the Warsaw U-200P Cyclotron were performed in collaboration with scientists from the Institute for Nuclear Studies in Kiev, Ukraine. The aim of the experiments was to investigate isotopic effects in the scattering of 11 B from carbon nuclides. Also, excited states of 6 Li predicted theoretically but never seen in experiments were investigated by means of one-neutron transfer reactions. Proton induced reactions were investigated theoretically by means of the multistep-direct model. Good agreement with the experimental data was achieved. The mechanism of fragments production in collisions of 197 Au with a gold target in the wide range of energies was studied by ALADIN and INDRA Collaborations. The production of η mesons from proton - proton collisions was investigated experimentally at the Juelich Cooler Synchrotron COSY. - Atomic physics: The ionisation of Au, Bi, Th and U atoms by Si ions was investigated in collaboration with the Swietokrzyska Academy, Kielce, and the University of Erlangen-Nuernberg. - Materials research: The sensitivity of the Solid State Nuclear Track PM-355 detectors was tested against intensive gamma and electron radiation. Moreover, using a monoenergetic sulphur ion beam from the Warsaw Cyclotron, the

Nuclear Symmetry Energy and the Breaking of the Isospin Symmetry: How Do They Reconcile with Each Other?

Science.gov (United States)

Roca-Maza, X; Colò, G; Sagawa, H

2018-05-18

We analyze and propose a solution to the apparent inconsistency between our current knowledge of the equation of state of asymmetric nuclear matter, the energy of the isobaric analog state (IAS) in a heavy nucleus such as ^{208}Pb, and the isospin symmetry breaking forces in the nuclear medium. This is achieved by performing state-of-the-art Hartree-Fock plus random phase approximation calculations of the IAS that include all isospin symmetry breaking contributions. To this aim, we propose a new effective interaction that is successful in reproducing the IAS excitation energy without compromising other properties of finite nuclei.

Parameters for calculation of nuclear reactions of relevance to non-energy nuclear applications (Reference Input Parameter Library: Phase III). Summary report of the first research coordination meeting

International Nuclear Information System (INIS)

Capote Noy, R.

2004-08-01

A summary is given of the First Research Coordination Meeting on Parameters for Calculation of Nuclear Reactions of Relevance to Non-Energy Nuclear Applications (Reference Input Parameter Library: Phase III), including a critical review of the RIPL-2 file. The new library should serve as input for theoretical calculations of nuclear reaction data at incident energies up to 200 MeV, as needed for energy and non-energy modern applications of nuclear data. Technical discussions and the resulting work plan of the Coordinated Research Programme are summarized, along with actions and deadlines. Participants' contributions to the RCM are also attached. (author)

Statistical theory of neutron nuclear reactions

International Nuclear Information System (INIS)

Moldauer, P.A.

1978-02-01

The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states

Statistical theory of neutron nuclear reactions

International Nuclear Information System (INIS)

Moldauer, P.A.

1980-01-01

The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states. (author)

Sequential series for nuclear reactions

International Nuclear Information System (INIS)

Izumo, Ko

1975-01-01

A new time-dependent treatment of nuclear reactions is given, in which the wave function of compound nucleus is expanded by a sequential series of the reaction processes. The wave functions of the sequential series form another complete set of compound nucleus at the limit Δt→0. It is pointed out that the wave function is characterized by the quantities: the number of degrees of freedom of motion n, the period of the motion (Poincare cycle) tsub(n), the delay time t sub(nμ) and the relaxation time tausub(n) to the equilibrium of compound nucleus, instead of the usual quantum number lambda, the energy eigenvalue Esub(lambda) and the total width GAMMAsub(lambda) of resonance levels, respectively. The transition matrix elements and the yields of nuclear reactions also become the functions of time given by the Fourier transform of the usual ones. The Poincare cycles of compound nuclei are compared with the observed correlations among resonance levels, which are about 10 -17 --10 -16 sec for medium and heavy nuclei and about 10 -20 sec for the intermediate resonances. (auth.)

Statistical theory of neutron nuclear reactions

International Nuclear Information System (INIS)

Moldauer, P.A.

1975-01-01

The statistical theory of average neutron nucleus reaction cross sections is reviewed with emphasis on the justification of the Hauser Feshbach formula and its modifications for situations including isolated compound nucleus resonances, overlapping and interfering resonances, the competition of compound and direct reactions, and continuous treatment of residual nuclear states. 3 figures

Follow-up Study of ITER Safety Analysis : Large In-vessel First Wall Pipe Break with Wet Confinement Bypass

Energy Technology Data Exchange (ETDEWEB)

Moon, Sung Bo; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2014-10-15

Previous researches have been analyzed risk assessments of fusion reactors that are dangerous in the severe accidents where the radioactive material released from confinement building to the environment. To simulate the severe accidents in ITER, a number of thermal hydraulics simulation codes were used. Before construction of the fusion reactor, to obtain ITER license about safety issue, MELCOR is chosen as one of the several codes to be used to perform ITER safety analyses. Qualification of the simulation code is to simulate the cooling system in ITER, the transport of radionuclides during design basis accidents (DBAs) including beyond design basis accidents (BDBAs). MELCOR is fully integrated code that models the accidents in Light Water Reactor (LWR). To analyze the accidents in ITER, MELCOR 1.8.2 version is modified. In the nuclear fusion system, the amount of released radioactive material is criteria for safety permission. Tritium (or tritiated water: HTO) and radioactive dust aerosol are the source of radioactive leakage. In the Generic Site Safety Report (GSSR) for the ITER plant, Table I lists the release guidelines for tritium and activation products for normal operation, incidents and accidents. Several accident analyses have been studied to know how much radioactive material could be released from the severe accidents. In the present work, The MELCOR input deck of large First Wall (FW) coolant leak (pipe break) is used to study and radioactive material leakage thorough bypass accident are studied to follow up the ITER safety analysis. In this research, follow-up study of the in-vessel inboard/inboard-outboard FW pipe break was analyzed to investigate the amount of leakage of radioactive aerosol. All of the accident cases released the lower amount of radioactive aerosol compared to the IAEA guide lines. In addition, the OBB pipe break made lower HTO aerosol leakage because of condensation of HTO and adsorption between coolant and aerosol.

When is a break-up of Gazprom good for Russia?

International Nuclear Information System (INIS)

Tsygankova, Marina

2010-01-01

In the late 1990s, several proposals for a structural reform that would bring competition and market prices to the Russian gas industry were intensely debated. Splitting up Russian gas monopolist Gazprom into several producing companies was a considered option. In this paper, I examine theoretically and numerically how a split-up of Gazprom would affect Russian national welfare. Results show that under the current gas market structures in Europe and Russia, the split-up of Gazprom's monopoly might not be beneficial for Russia. However, analysis in the paper indicates that the market shares that Gazprom has in both Russian domestic and European gas markets are important in determining whether Gazprom's dominance is supported under the national welfare criteria. When Gazprom has small market share in Europe and large market share in Russia, a break-up of Gazprom might plausibly result in increase of Russian national welfare. (author)

Nuclear-reaction rates in the thermonuclear runaway phase of accreting neutron stars

International Nuclear Information System (INIS)

Wiescher, M.; Barnard, V.; Goerres, J.; Fisker, J.L.; Martinez-Pinedo, G.; Langanke, K.; Rembges, F.; Thielemann, F.K.; Schatz, H.

2002-01-01

The rp-process has been suggested as the dominant nucleosynthesis process in explosive hydrogen burning at high temperature and density conditions. The process is characterized by a sequence of fast proton capture reactions and subsequent β-decays. The reaction path of the rp-process runs along the drip line up to Z∼50. Most of the charged-particle reaction rates for the reaction path are presently based on statistical Hauser-Feshbach calculations. While these rates are supposed to be reliable within a factor of two for conditions of high density in the compound nuclei, discrepancies may occur for nuclei near closed shells or near the proton drip line where the Q-values of proton capture processes are typically very small. It has been argued that the thermonuclear runaway is less sensitive to the reaction rates because of the rapid time-scale of the event. However, since these processes may operate at the same time-scale as fast mixing and convection processes, a change in reaction rates indeed may have a significant impact. In this paper we present two examples, the break-out from the hot CNO cycles, and the thermonuclear runaway in X-ray bursts itself, where changes in reaction rates have a direct impact on time-scale, energy generation and nucleosynthesis predictions for the explosive event. (orig.)

Quantitative surface analysis using deuteron-induced nuclear reactions

International Nuclear Information System (INIS)

Afarideh, Hossein

1991-01-01

The nuclear reaction analysis (NRA) technique consists of looking at the energies of the reaction products which uniquely define the particular elements present in the sample and it analysis the yield/energy distribution to reveal depth profiles. A summary of the basic features of the nuclear reaction analysis technique is given, in particular emphasis is placed on quantitative light element determination using (d,p) and (d,alpha) reactions. The experimental apparatus is also described. Finally a set of (d,p) spectra for the elements Z=3 to Z=17 using 2 MeV incident deutrons is included together with example of more applications of the (d,alpha) spectra. (author)

Studies of nuclear second moments for pre-equilibrium nuclear reaction theories

International Nuclear Information System (INIS)

Sato, K.; Yoshida, S.

1987-01-01

The nuclear second moments, important inputs to pre-equilibrium reaction theories, are evaluated by assuming a simple model. The positive definite nature of the second moments is examined, and the nuclear level densities are calculated using positive definite second moments. (orig.)

Nuclear Reaction and Structure Databases of the National Nuclear Data Center

International Nuclear Information System (INIS)

Pritychenko, B.; Arcilla, R.; Herman, M. W.; Oblozinsky, P.; Rochman, D.; Sonzogni, A. A.; Tuli, J. K.; Winchell, D. F.

2006-01-01

The National Nuclear Data Center (NNDC) collects, evaluates, and disseminates nuclear physics data for basic research and applied nuclear technologies. In 2004, the NNDC migrated all databases into modern relational database software, installed new generation of Linux servers and developed new Java-based Web service. This nuclear database development means much faster, more flexible and more convenient service to all users in the United States. These nuclear reaction and structure database developments as well as related Web services are briefly described

Use of SSNTD for measuring nuclear reactions

Energy Technology Data Exchange (ETDEWEB)

Bakr, M H [Division of Baic Nucl. Sc., NRC, Atomic Energy Authority Cairo (Egypt)

1997-12-31

Solid state nuclear track detectors (SSNTD) technique in nuclear reactions is reviewed. Special attention is given to the study of Makrofol-E films using a proposed optimum etching solution. The etching rate was 10.5 Mm/ hour. The energy resolution was measured and estimated to be 600 and 400 KeV in the energy ranges 1-2 MeV and 2-3 MeV respectively. Based on these results, the sensitivity threshold for gamma-particles in Makrofol-E is shifted up to 1 MeV, otherwise, there will be no discrimination between the etch - pits of gamma- particles with energies ranging from 0 to 1 MeV. The full angular distribution of the gamma-groups were measured in one run by means of a SSNTD sheel surrounding the target. A scattering chamber designed for gamma-particle angular distribution measurements is described. An example of the influence of energy loss in degrading Al foils in eliminating the energy angle dependence is given. The numerous curves of the range -energy dependence of gamma - particles in Makrofol - E after passing Al foils of different thicknesses are scaled in one schematic normograph. The later simplifies the process of choosing the suitable Al foil thickness or of determining the range- energy relation. The angular distributions of five gamma- groups from the {sup 56} Co (P, gamma) {sup 56} Fe reaction in the proton energy 1.6 -2.4 MeV have been measured using the designed chamber. A Makrofol - E film of 200 Mm thickness was exposed to the reaction products for 5 hours. This time was enough to get the angular distribution for (d/d) in the range 5-72 Mm barn/ster.

Investigation of phosphorous in thin films using the {sup 31}P(α,p){sup 34}S nuclear reaction

Energy Technology Data Exchange (ETDEWEB)

Pitthan, E., E-mail: eduardo.pitthan@ufrgs.br [PGMICRO, UFRGS, 91509-900 Porto Alegre, RS (Brazil); Gobbi, A.L. [Laboratório Nacional de Nanotecnologia, 13083-100 Campinas, SP (Brazil); Stedile, F.C. [PGMICRO, UFRGS, 91509-900 Porto Alegre, RS (Brazil); Instituto de Química, UFRGS, 91509-900 Porto Alegre, RS (Brazil)

2016-03-15

Phosphorus detection and quantification were obtained, using the {sup 31}P(α,p){sup 34}S nuclear reaction and Rutherford Backscattering Spectrometry, in deposited silicon oxide films containing phosphorus and in carbon substrates implanted with phosphorus. It was possible to determine the total amount of phosphorus using the resonance at 3.640 MeV of the {sup 31}P(α,p){sup 34}S nuclear reaction in samples with phosphorus present in up to 23 nm depth. Phosphorous amounts as low as 4 × 10{sup 14} cm{sup −2} were detected. Results obtained by nuclear reaction were in good agreement with those from RBS measurements. Possible applications of phosphorus deposition routes used in this work are discussed.

International conference: Features of nuclear excitation states and mechanisms of nuclear reactions. 51. Meeting on nuclear spectroscopy and nuclear structure. The book of abstracts

International Nuclear Information System (INIS)

2001-01-01

Results of the LI Meeting on Nuclear Spectroscopy and Nuclear Structure are presented. Properties of excited states of atomic nuclei and mechanisms of nuclear reactions are considered. Studies on the theory of nucleus and fundamental interactions pertinent to experimental study of nuclei properties and mechanisms of nuclear reactions, technique and methods of experiment, application of nuclear-physical method, are provided [ru

Theoretical studies in nuclear reactions and nuclear structure. Progress report

Energy Technology Data Exchange (ETDEWEB)

1992-05-01

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. Hadrons in nuclear matter; the structure of hadrons; relativistic nuclear physics and heavy ion dynamics and related processes. The section on hadrons in nuclear matter groups together research items which are aimed at exploring ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. A very interesting result has been the finding that QCD sum rules supply a new insight into the decrease of the nucleon`s mass in the nuclear medium. The quark condensate, which characterizes spontaneous chiral symmetry breaking of the late QCD vacuum, decreases in nuclear matter and this is responsible for the decrease of the nucleon`s mass. The section on the structure of hadrons contains progress reports on our research aimed at understanding the structure of the nucleon. Widely different approaches are being studied, e.g., lattice gauge calculations, QCD sum rules, quark-meson models with confinement and other hedgehog models. A major goal of this type of research is to develop appropriate links between nuclear physics and QCD. The section on relativistic nuclear physics represents our continuing interest in developing an appropriate relativistic framework for nuclear dynamics. A Lorentz-invariant description of the nuclear force suggests a similar decrease of the nucleon`s mass in the nuclear medium as has been found from QCD sum rules. Work in progress extends previous successes in elastic scattering to inelastic scattering of protons by nuclei. The section on heavy ion dynamics and related processes reports on research into the e{sup +}e{sup {minus}} problem and heavy ion dynamics.

Reaction list for charged-particle-induced nuclear reactions: Z = 1 to Z = 98 (H to Cf), July 1973--September 1974

International Nuclear Information System (INIS)

McGowan, F.K.; Milner, W.T.

1975-01-01

This Reaction List for charged-particle-induced nuclear reactions has been prepared from the journal literature for the period from July 1973 through September 1974. Each published experimental paper is listed under the target nucleus in the nuclear reaction with a brief statement of the type of data in the paper. The nuclear reaction is denoted by A(a,b)B, where the mass of a is greater than or equal to (one nucleon mass). There is no restriction on energy. Nuclear reactions involving mesons in the outgoing channel are not included. Theoretical papers which treat directly with the analysis of nuclear reaction data and results are included in the Reaction List. The cutoff date for literature was September 30, 1974. (U.S.)

Overview of Light Hydrogen-Based Low Energy Nuclear Reactions

Science.gov (United States)

Miley, George H.; Shrestha, Prajakti J.

This paper reviews light water and hydrogen-based low-energy nuclear reactions (LENRs) including the different methodologies used to study these reactions and the results obtained. Reports of excess heat production, transmutation reactions, and nuclear radiation emission are cited. An aim of this review is to present a summary of the present status of light water LENR research and provide some insight into where this research is heading.

The nuclear structure and low-energy reactions (NSLER) collaboration

International Nuclear Information System (INIS)

Dean, D J

2006-01-01

The long-term vision of the Nuclear Structure and Low-Energy Reactions (NSLER) collaboration is to arrive at a comprehensive and unified description of nuclei and their reactions that is grounded in the interactions between the constituent nucleons. For this purpose, we will develop a universal energy density functional for nuclei and replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that will deliver maximum predictive power with minimal uncertainties that are well quantified. Nuclear structure and reactions play an essential role in the science to be investigated at rare isotope facilities, and in nuclear physics applications to the Science-Based Stockpile Stewardship Program, next-generation reactors, and threat reduction. We anticipate an expansion of the computational techniques and methods we currently employ, and developments of new treatments, to take advantage of petascale architectures and demonstrate the capability of the leadership class machines to deliver new science heretofore impossible

Compilation status and research topics in Hokkaido University Nuclear Reaction Data Centre

International Nuclear Information System (INIS)

Aikawa, M.; Furutachi, N.; Katō, K.; Ebata, S.; Ichinkhorloo, D.; Imai, S.; Sarsembayeva, A.; Zhou, B.; Otuka, N.

2015-01-01

Nuclear reaction data are necessary and applicable for many application fields. The nuclear reaction data must be compiled into a database for convenient availability. One such database is the EXFOR database maintained by the International Network of Nuclear Reaction Data Centres (NRDC). As a member of the NRDC, the Hokkaido University Nuclear Reaction Data Centre (JCPRG) compiles charged-particle induced reaction data and contributes about 10 percent of the EXFOR database. In this paper, we show the recent compilation status and related research topics of JCPRG. (author)

International Network of Nuclear Reaction Data Centres

International Nuclear Information System (INIS)

Otsuka, Naohiko; Dunaeva, Svetlana

2010-11-01

The activities of fourteen nuclear data centres are summarized, and their cooperation under the auspices of the International Atomic Energy Agency is described. Each of the centres provides coverage for different geographical zones and/or specific types of nuclear data, thus together providing a complete service for users worldwide. The International Network of Nuclear Reaction Data Centres (NRDC) was established with the objective of providing nuclear physics databases that are required for nuclear technology (encompassing energy and non-energy applications) by coordinating the collection, compilation and dissemination of nuclear data on an international scale. (author)

A Model of the Bubble Break-up in a Turbulent Flow; Modelizacion de la rotura de una Burbuja en un Flujo Turbulento

Energy Technology Data Exchange (ETDEWEB)

Bayod, R.; Rodriguez Rodriguez, J.; Martinez Bazan, C.

2005-07-01

In this report, a simplified model of the break-up of an air bubble in a turbulent water flow is proposed and analyzed numerically. According to Hinze's theory, and our experimental observations, the external flow field is assumed asymmetric and irrotational for away from the bubble. furthermore the turbulent flow-field is modelled by an asymmetric hyperbolic flow-field and the evolution of the air-water interface is calculated by the levels-set method for a wide range of Reynolds and Weber numbers. Therefore, the break-up times are obtained for super-critical weber numbers and different Reynolds numbers. Therefore, the break-up times are obtained for super-critical Weber and Reynolds numbers allows the comparison of the numeric with our experimental results. Other possible break-up mechanisms for subcritical Weber number, i. e. the break-up by resonance, are also considered. (Author) 20 refs.

The (n,p) reaction as a probe of nuclear structure

International Nuclear Information System (INIS)

Jackson, K.P.; Celler, A.

1988-08-01

An account is given of some results of studies of the (n,p) reaction on nuclear targets at TRIUMF. The (n,p) reaction, inducing spin flip transitions in isospin space, appears to exhibit a unique sensitivity to certain aspects of nuclear structure. The TRIUMF facility is the first to exploit the (n,p) reaction as a detailed probe of nuclear structure at energies above 65 MeV. In the (n,p) reaction Fermi transitions are absent, but there is a dramatic impact on Gamow-Teller and other collective transactions. Some nuclear transition matrix elements can be estimated on the basis of (n,p) measurements. Experiments have been carried out at TRIUMF on Li 6 , Fe 5 4, and Zr 9 0 targets. The calibration of the (n,p) reaction as a probe of the Gamow-Teller strength B + GT has been achieved for three targets. (L.L.) (45 refs., 10 figs.)

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2001-01-01

Full text: The last year of the twentieth-century was productive for our Department. Although the name of the Department suggests that we are all involved in investigations of nuclear reactions, in fact our activities are spread over three major domains: nuclear, atomic and material physics. Some of the projects we were involved in the last year have been realized using national facilities and accelerators, like the Van de Graaff accelerator of our Department at 69 Hoza Street, Warsaw Cyclotron U-200P of Warsaw University, and compact C30 cyclotron of our Institute at Swierk. Other projects were done abroad, using facilities of the Gesellschaft fuer Schwerionenforschung in Darmstadt, Institute de Physique Nucleaire at Orsay, and Universitaet Erlangen-Nuernberg in Erlangen. We carried out our work in close collaborations with physicists from many laboratories, Polish and foreign. - Low energy nuclear reactions. In collaboration with scientists from Ukraine experiments, using heavy ion beam provided by the Warsaw Cyclotron, were started. The aim of the experiments is to study nuclear reactions leading to the exotic light nuclei in exit channels and energy dependence of the nucleus - nucleus interaction. Efforts were made to develop a multistep direct model of nuclear reactions. In the model contributions due to the low energy collective excitations were taken into account. Good agreement with the experimental data was achieved. - Multifragmentation of relativistic heavy ions. ALADIN Collaboration studied multifragmentation reactions induced by relativistic heavy ions. The main activities of our scientists concentrated on an upgrade of the detecting system in order to replace photo multipliers with large area avalanche photodiodes in the central section of the TOF-wall. Some tests of the photodiodes manufactured by Advanced Photonix Inc. were performed using standard β - and γ-sources. - Structure of a nucleon. Decay properties of the Roper resonance were studied. A

Break-up fragment topology in statistical multifragmentation models

International Nuclear Information System (INIS)

Raduta, Ad. R.

2009-01-01

Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As long as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation-energy-freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated nonuniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

Optimizing Nuclear Reaction Analysis (NRA) using Bayesian Experimental Design

International Nuclear Information System (INIS)

Toussaint, Udo von; Schwarz-Selinger, Thomas; Gori, Silvio

2008-01-01

Nuclear Reaction Analysis with 3 He holds the promise to measure Deuterium depth profiles up to large depths. However, the extraction of the depth profile from the measured data is an ill-posed inversion problem. Here we demonstrate how Bayesian Experimental Design can be used to optimize the number of measurements as well as the measurement energies to maximize the information gain. Comparison of the inversion properties of the optimized design with standard settings reveals huge possible gains. Application of the posterior sampling method allows to optimize the experimental settings interactively during the measurement process.

Extension of activation cross section data of deuteron induced nuclear reactions on rhodium up to 50 MeV

Energy Technology Data Exchange (ETDEWEB)

Hermanne, A. [Cyclotron Laboratory, Vrije Universiteit Brussel, Brussels (Belgium); Tárkányi, F.; Takács, S.; Ditrói, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary)

2015-11-01

In the frame of the systematical study of light ion induced nuclear reactions activation cross sections for deuteron induced reactions on monoisotopic {sup 103}Rh were extended to 50 MeV incident energy. Excitation functions were measured in the 49.8–36.6 MeV energy range for the {sup 103}Rh(d,xn){sup 100,101}Pd, {sup 103}Rh(d,pxn){sup 99m,99g,100,101m,101g,102m,102g}Rh and {sup 103}Rh(d,x){sup 97,103}Ru reactions by using the stacked foil irradiation technique and off-line high resolution γ-ray spectrometry. The experimental results are compared to our previous results and to the theoretical predictions in the TENDL-2014 library (TALYS 1.6 code).

Microscopic description of nuclear reactions

International Nuclear Information System (INIS)

Gorbatov, A.M.

1992-01-01

The genealogical series method has been extended to the continuous spectrum of the many-body systems. New nonlinear integral equations have been formulated to perform the microscopical description of the nuclear reactions with arbitrary number of particles. The way to solve them numerically is demonstrated

Experimental (Network) and Evaluated Nuclear Reaction Data at NDS

International Nuclear Information System (INIS)

Otsuka, N.; Semkova, V.; Simakov, S.P.; Zerkin, V.

2011-01-01

Dr Simakov of Nuclear Data Services Unit in the Nuclear Data Section (NDS) gave a brief overview of the data compilation and evaluation activities in the nuclear data community: experimental nuclear reaction data (EXFOR, http://www-nds.iaea.org/exfor/) and evaluated nuclear reaction data (ENDF, http://www-nds.iaea.org/endf). The International Network of Nuclear Reaction Data Centres (NRDC) coordinated by NDS includes 14 Centres in 8 Countries (China, Hungary, India, Japan, Korea, Russian, Ukraine, USA) and 2 International Organizations (NEA, IAEA). It had the first meeting of four core centres (Brookhaven, Saclay, Obninsk, Vienna) in 1966 and the EXFOR was adopted as an official data exchange format. In 2000, IAEA implemented the EXFOR database as a relational multiform database and the EXFOR is a trusted, increasing and living database with 19100 experimental works (as of September 2011) and 141600 data tables. The EXFOR provides a compilation control system for selection of articles and compilation of data and the NRDC home page provides manuals, documents and codes. The nuclear data can be retrieved by the web-retrieval system or distributed on a DVD on request. The EXFOR data play a critical role in the development of evaluated nuclear reaction data. There are several major general purpose libraries: ENDF (US), CENDL (China), JEFF (EU), JENDL (Japan) and RUSFOND (Russia). In addition, there are special libraries for particular applications: EAF (European Activation File), FENDL (Fusion Evaluated Nuclear Data Library for ITER neutronics), IBANDL (Ion Beam Analysis Nuclear Data Library for surface analysis of solids), IRDF, DXS (Dosimetry, radiation damage and gas production data) and Medical portal. Dr V. Zerkin of NDS demonstrated the data retrieval from the EXFOR database and the ENDF library.

Experimental (Network) and Evaluated Nuclear Reaction Data at NDS

Energy Technology Data Exchange (ETDEWEB)

Otsuka, N; Semkova, V; Simakov, S P; Zerkin, V [Nuclear Data Services Unit, Nuclear Data Section, IAEA, Vienna (Austria)

2011-11-15

Dr Simakov of Nuclear Data Services Unit in the Nuclear Data Section (NDS) gave a brief overview of the data compilation and evaluation activities in the nuclear data community: experimental nuclear reaction data (EXFOR, http://www-nds.iaea.org/exfor/) and evaluated nuclear reaction data (ENDF, http://www-nds.iaea.org/endf). The International Network of Nuclear Reaction Data Centres (NRDC) coordinated by NDS includes 14 Centres in 8 Countries (China, Hungary, India, Japan, Korea, Russian, Ukraine, USA) and 2 International Organizations (NEA, IAEA). It had the first meeting of four core centres (Brookhaven, Saclay, Obninsk, Vienna) in 1966 and the EXFOR was adopted as an official data exchange format. In 2000, IAEA implemented the EXFOR database as a relational multiform database and the EXFOR is a trusted, increasing and living database with 19100 experimental works (as of September 2011) and 141600 data tables. The EXFOR provides a compilation control system for selection of articles and compilation of data and the NRDC home page provides manuals, documents and codes. The nuclear data can be retrieved by the web-retrieval system or distributed on a DVD on request. The EXFOR data play a critical role in the development of evaluated nuclear reaction data. There are several major general purpose libraries: ENDF (US), CENDL (China), JEFF (EU), JENDL (Japan) and RUSFOND (Russia). In addition, there are special libraries for particular applications: EAF (European Activation File), FENDL (Fusion Evaluated Nuclear Data Library for ITER neutronics), IBANDL (Ion Beam Analysis Nuclear Data Library for surface analysis of solids), IRDF, DXS (Dosimetry, radiation damage and gas production data) and Medical portal. Dr V. Zerkin of NDS demonstrated the data retrieval from the EXFOR database and the ENDF library.

Astrophysical Nuclear Reaction Rates in the Dense Metallic Environments

Science.gov (United States)

Kilic, Ali Ihsan

2017-09-01

Nuclear reaction rates can be enhanced by many orders of magnitude in dense and relatively cold astrophysical plasmas such as in white dwarfs, brown dwarfs, and giant planets. Similar conditions are also present in supernova explosions where the ignition conditions are vital for cosmological models. White dwarfs are compact objects that have both extremely high interior densities and very strong local magnetic fields. For the first time, a new formula has been developed to explain cross section and reaction rate quantities for light elements that includes not only the nuclear component but also the material dependence, magnetic field, and crystal structure dependency in dense metallic environments. I will present the impact of the developed formula on the cross section and reaction rates for light elements. This could have possible technological applications in energy production using nuclear fusion reactions.

Nuclear dynamics around the barrier: from fusion to evaporation

International Nuclear Information System (INIS)

Simenel, Cedric

2003-01-01

This work is devoted to aspects of nuclear dynamics around the barrier. It is shown that for fusion reactions, the Coulomb field couples relative motion of nuclei to rotation of a deformed projectile independently of the energy and the charge of the nuclei. An experimental study of the reaction 6 He + 190 Os via gamma spectroscopy of product nuclei has shown that the break up of the 6 He is coupled to the relative motion too, a strong hindrance resulting in the fusion around and above the fusion barrier. The path to fusion after overcoming the barrier, especially the charge equilibration, have been studied in the framework of the TDHF theory via the preequilibrium GDR excited in N/Z asymmetric reactions. An application to formation of the super-heavy elements has been proposed. Finally, couplings between protons and neutrons have been shown up in mean field calculations. Their main expected effect is an emission of protons under the Coulomb barrier. (author)

Results of small break LOCA analysis for Kuosheng nuclear power plant using the RELAP5YA computer code

International Nuclear Information System (INIS)

Wang, L.C.; Jeng, S.C.; Chung, N.M.

2004-01-01

One lesson learned from the Three Mile Island (TMI) accident was the analysis methods used by Nuclear Steam Supply System (NSSS) vendors and/or nuclear fuel suppliers for small break Loss Of Coolant Accident (LOCA) analysis for compliance with appendix K to 10CFR50 should be revised, documented and submitted for USNRC approval and the plant-specific calculations using NRC-approved models for small-break LOCA to show compliance with 10CFR50.46 should be submitted for NRC approval. A study by Taiwan Power Company (TPC) under the guidance of Yankee Atomic Electric Company (YAEC) has been undertaken to perform this analysis for Kuosheng nuclear power plant. This paper presents the results of the analysis that are useful in satisfying the same requirements of the Republic Of China Atomic Energy Commission (ROCAEC). (author)

Third international workshop on compound nuclear reactions and related topics. Book of abstracts

International Nuclear Information System (INIS)

2012-09-01

The conference was divided into the following sections: Fission; Surrogate reactions; Heavy ion reactions; Neutron-induced reactions; Gamma-ray strength functions; Nuclear astrophysics; Superheavy nuclei; Nuclear level density; Various nuclear reactions; Optical model simulations; and Pre-equilibrium. The publication contains 82 abstracts. (P.A.)

Calculation of neutron monitor reaction cross sections of {sup 90}Zr in energy region up to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Qingbiao, Shen; Baosheng, Yu; Dunjiu, Cai [Chinese Nuclear Data Center, Beijing, BJ (China)

1996-06-01

Many nuclear data for n + {sup 90}Zr reaction were calculated by using optical model evaporation model and exciton model. The program SPEC, including the first to the sixth particle emission processes, was used in our calculations. The calculated results show that the activation products {sup 89,88}Zr and {sup 88,87}Y are important neutron monitor reaction products for n + {sup 90}Zr reaction in energy range up to 100 MeV. (4 figs.).

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1992-01-01

The research program described touches five areas of nuclear physics: nuclear structure studies at high spin (hyperdeformation in the mass A ≅ 182 region, structure of 182 Hg and 182 Au at high spin, a highly deformed band in 136 Pm and the anomalous h 11/2 proton crossing in the A∼135 superdeformed region), studies at the interface between structure and reactions (population of entry states in heavy-ion fusion reactions, nuclear structure effects in proton evaporation spectra, nuclear structure- dependent entry state population by total spectroscopy, entrance channel effects in fusion near the barrier, lifetimes of subbarrier α particles by the atomic clock method), production and study of hot nuclei (the statistical model evaporation code EVAP, statistical emission of deuterons and tritons from highly excited compound nuclei, heavy-fragment emission as a probe of the thermal properties of highly excited compound nuclei, use of incoming-wave boundary condition transmission coefficients in the statistical model: implications in the particle evaporation spectra, study of transparency in the optical model), reaction mechanism studies (binary character of highly dissipative 209 Bi + 136 Xe collisions at E/A=28.2 MeV), and development and use of novel techniques and instrumentation in these areas of research (including a 4π channel selection device, a novel x-ray detector, and a simple channel-selecting detector)

A Southern Hemisphere origin for campanulid angiosperms, with traces of the break-up of Gondwana.

Science.gov (United States)

Beaulieu, Jeremy M; Tank, David C; Donoghue, Michael J

2013-04-08

New powerful biogeographic methods have focused attention on long-standing hypotheses regarding the influence of the break-up of Gondwana on the biogeography of Southern Hemisphere plant groups. Studies to date have often concluded that these groups are too young to have been influenced by these ancient continental movements. Here we examine a much larger and older angiosperm clade, the Campanulidae, and infer its biogeographic history by combining Bayesian divergence time information with a likelihood-based biogeographic model focused on the Gondwanan landmasses. Our analyses imply that campanulids likely originated in the middle Albian (~105 Ma), and that a substantial portion of the early evolutionary history of campanulids took place in the Southern Hemisphere, despite their greater species richness in the Northern Hemisphere today. We also discovered several disjunctions that show biogeographic and temporal correspondence with the break-up of Gondwana. While it is possible to discern traces of the break-up of Gondwana in clades that are old enough, it will generally be difficult to be confident in continental movement as the prime cause of geographic disjunctions. This follows from the need for the geographic disjunction, the inferred biogeographic scenario, and the dating of the lineage splitting events to be consistent with the causal hypothesis.

Manual on usage of the Nuclear Reaction Data File (NRDF)

International Nuclear Information System (INIS)

1984-10-01

In the computer in the Institute for Nuclear Study, University of Tokyo, there is set up a Nuclear Reaction Data File (NRDF) which has been built in Hokkaido University. While the data base is growing year after year, its trial usage is for the purpose of joint utilization by educational institutions. In section 1, examples of the retrieval are presented to have the user familiarize with NRDF. In section 2, the terms used in retrieval are given in table. Then, in section 3, as a summary of the examples, structure of the retrieval commands is explained. In section 4, for the retrieval results on a CRT, cautions in reading are given. Finally, in section 5, general cautions in usage of NRDF are given. (Mori, K.)

Formation of beads-on-a-string structures during break-up of viscoelastic filaments

Science.gov (United States)

Bhat, Pradeep P.; Appathurai, Santosh; Harris, Michael T.; Pasquali, Matteo; McKinley, Gareth H.; Basaran, Osman A.

2010-08-01

Break-up of viscoelastic filaments is pervasive in both nature and technology. If a filament is formed by placing a drop of saliva between a thumb and forefinger and is stretched, the filament's morphology close to break-up corresponds to beads of several sizes interconnected by slender threads. Although there is general agreement that formation of such beads-on-a-string (BOAS) structures occurs only for viscoelastic fluids, the underlying physics remains unclear and controversial. The physics leading to the formation of BOAS structures is probed by numerical simulation. Computations reveal that viscoelasticity alone does not give rise to a small, satellite bead between two much larger main beads but that inertia is required for its formation. Viscoelasticity, however, enhances the growth of the bead and delays pinch-off, which leads to a relatively long-lived beaded structure. We also show for the first time theoretically that yet smaller, sub-satellite beads can also form as seen in experiments.

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2004-01-01

Full text: In spite of reduced personnel the number of papers published and in press exceeded fifty, almost ten more than a year ago. Another good sign is the growing number of PhD students. The following short reports cover the three major domains of our scientific activities: nuclear, material and atomic physics. Nuclear physics: The structure of light nuclei was investigated, and studies of nuclear reactions induced by heavy ions were performed including experiments at the Heavy Ion Laboratory of Warsaw University. The experiments were carried out in collaboration with scientists from the Institute of Nuclear Research from Kiev, Ukraine. Proton induced reactions on zirconium were investigated theoretically by means of a multistep-direct model extended for the unbound particle - hole states. Good agreement with the experimental data was achieved. Isospin effects in multifragmentation of relativistic heavy ions were studied by the ALADIN Collaboration. Elements of a new generation detector PANDA were tested experimentally using a proton beam provided by the C-30 compact cyclotron at Swierk. Evidence of a narrow baryon state was found in a quasi - real photoproduction on the deuterium target by the HERMES Collaboration. Atomic physics: Ionisation of selected heavy elements by sulphur ions was investigated in collaboration with the Swietokrzyska Academy, Kielce. Materials research: Hydrogen release from ultrahigh molecular weight polythene was investigated by means of an α - particle beam from the Van de Graaff accelerator of our Department. Last but not least, many of our colleagues have been involved in education. Lectures on nuclear physics, accelerators, detectors used in nuclear research as well as nuclear methods applied in solid state studies for students from many high schools of Warsaw and for students of Warsaw University were given by Dr. Andrzej Korman and Dr. Lech Nowicki. Also, our Department made a significant contribution to the 7 th Science

Effect of the Pauli principle and channel coupling on the nuclear reactions, 2

International Nuclear Information System (INIS)

Kanada, Hiroyuki; Kaneko, Tsuneo; Nomoto, Morikazu

1976-01-01

The effect of the Pauli principle on nuclear reactions of a six-nucleon system is investigated in the presence of a breakup channel, by using the resonating group method (RGM). The microscopic treatment with full exchange effects for the t( 3 He, d) 4 He reaction is examined together with the 3 He-t and d- 4 He elastic scattering. It is shown that the exchange effects (especially owing to the Pauli principle) play an important role in the differential cross section in the backward region. The t( 3 He, d) 4 He reaction is examined by decomposing the reaction processes into three terms, that is, proton stripping, neutron pick-up and residual processes. The asymmetry of the angular distribution for the t( 3 He, d) 4 He reaction is also discussed. (auth.)

Energy expenditure and heart rate response to breaking up sedentary time with three different physical activity interventions.

Science.gov (United States)

Carter, S E; Jones, M; Gladwell, V F

2015-05-01

Prolonged sedentary behaviour is associated with increased cardiovascular disease risk and decreased energy expenditure (EE). Workplace interventions breaking up sedentary time have increased EE but the cardiovascular responses are unknown. The practicalities of these interventions, such as required costs and workplace adaptations, are questioned. Calisthenics exercises overcome such limitations, but have not been assessed. The aim of this study was to assess the EE and heart rate (HR) response when breaking up sedentary time with a short bout of standing, walking or calisthenics. Twenty healthy participants (15 male) completed four 30 min conditions: a) 30 min sitting, or breaking up this period with two minutes of b) standing, c) treadmill walking (4 km·h(-1)) or d) a set of calisthenics exercises (including squats and lunges). HR and EE (indirect calorimetry) were assessed throughout. During the activity break, calisthenics caused the highest HR (90 ± 12 bpm) compared to all other conditions (Sit: 70 ± 12 bpm; Stand:72 ± 13 bpm; Walk:84 ± 10 bpm; p workplace sedentary time and improve cardiovascular health and assist in weight management. Copyright © 2015 Elsevier B.V. All rights reserved.

Low energy nuclear reaction polyplasmon postulate

Energy Technology Data Exchange (ETDEWEB)

Russell, John L. [201 Heritage Drive, Apt. 208, Canton, GA 30093 (United States)], E-mail: RUSSELLJL@aol.com

2008-11-15

An explanation is proposed for the nuclear reactions that occur in the electrolysis class of LENR processes. The proposed explanation postulates that a proton, or deuteron, dissolved in the hydrogen bearing metal cathode, absorbs its associated atomic electron to become a short lived state of the neutron with the resulting neutrino in a singular wave function centered on the neutron. The energy required to initiate this endothermic reaction is supplied either by the ion current during electrolysis type experiments, or by ion bombardment in plasma type experiments. It is the energy of this bombardment of the cathode with heavy ions that creates a coherent polyplasmon field within crystalline metallic grains that are present in the metal cathode of typical active electrolysis cells. The LENR process consists of a second order reaction mediated by a coherent plasmon field excited in the conduction electrons in a hydrogen bearing metal that is in the form of crystalline grains of the order of a few microns in dimension. The coherent plasmon field in each grain is called a polyplasmon. The metallic grains typically form during solidification of a metal, the impurities being forced to the grain surfaces. The resulting grain thus forms a resonant structure that can be filled with a number of coherent plasmons, i.e., a polyplasmon. Energy from the polyplasmon is coupled to the nucleus via electron capture by hydrogen. Because the neutrino has mass, its wave function has a second class of solutions. This description can take the form of a short lived pairing with the neutron that results from electron capture by the hydrogen nucleus. This short-lived compound particle is named the 'dion' and in the case of deuterium results in a 'dineutron'. Because the dion and dineutron are formed with essentially thermal kinetic energy, they can capture in nearby nuclei, either in hydrogen or in the host metal. Most of the resulting exothermic nuclear energy is

Low energy nuclear reaction polyplasmon postulate

International Nuclear Information System (INIS)

Russell, John L.

2008-01-01

An explanation is proposed for the nuclear reactions that occur in the electrolysis class of LENR processes. The proposed explanation postulates that a proton, or deuteron, dissolved in the hydrogen bearing metal cathode, absorbs its associated atomic electron to become a short lived state of the neutron with the resulting neutrino in a singular wave function centered on the neutron. The energy required to initiate this endothermic reaction is supplied either by the ion current during electrolysis type experiments, or by ion bombardment in plasma type experiments. It is the energy of this bombardment of the cathode with heavy ions that creates a coherent polyplasmon field within crystalline metallic grains that are present in the metal cathode of typical active electrolysis cells. The LENR process consists of a second order reaction mediated by a coherent plasmon field excited in the conduction electrons in a hydrogen bearing metal that is in the form of crystalline grains of the order of a few microns in dimension. The coherent plasmon field in each grain is called a polyplasmon. The metallic grains typically form during solidification of a metal, the impurities being forced to the grain surfaces. The resulting grain thus forms a resonant structure that can be filled with a number of coherent plasmons, i.e., a polyplasmon. Energy from the polyplasmon is coupled to the nucleus via electron capture by hydrogen. Because the neutrino has mass, its wave function has a second class of solutions. This description can take the form of a short lived pairing with the neutron that results from electron capture by the hydrogen nucleus. This short-lived compound particle is named the 'dion' and in the case of deuterium results in a 'dineutron'. Because the dion and dineutron are formed with essentially thermal kinetic energy, they can capture in nearby nuclei, either in hydrogen or in the host metal. Most of the resulting exothermic nuclear energy is absorbed in the plasmon

Microfluidic droplet generator with controlled break-up mechanism

KAUST Repository

Gonzalez, David Conchouso

2017-04-13

Droplet generation devices and systems that parallelize droplet generation devices are provided. The droplet generation devices can include a symmetric block-and-break system and a tapered droplet generation zone. The symmetric block-and-break system can include a pair of break channels and a pair of bypass channels symmetrically arranged with respect to the dispersed-phase input channel and the output channel. The droplet generation devices can generate monodisperse droplets with a predefined volume over a range of flow rates, pressures, and fluid properties. The droplet generation devices are therefore capable of parallelization to achieve large-capacity droplet generation, e.g. greater than 1 L/hr, with small overall coefficients of variation.

The effects of Vitamin A on tear break-up time of young adults ...

African Journals Online (AJOL)

The effects of Vitamin A on tear break-up time of young adults. ... healthy young adults; 50 males and 50 females all within the ages of 18 and 30 years were used for this study. Results showed a range of 13-28 seconds and a mean TBUT of

Neutron spectroscopy, nuclear structure, related topics. Abstracts

International Nuclear Information System (INIS)

Sukhovoj, A.M.

1996-01-01

Neutron spectroscopy, nuclear structure and related topics are considered. P, T-breaking, neutron beta decay, neutron radiative capture and neutron polarizability are discussed. Reaction with fast neutrons, methodical aspect low-energy fission are considered too

The role of nuclear reaction theory and data in nuclear energy and safety applications

International Nuclear Information System (INIS)

Schmidt, J.J.

1993-01-01

The nuclear data requirements for nuclear fission reactor design and safety computations are so large that they cannot be satisfied by experimental measurements alone. Nuclear reaction theories and models have recently been developed and refined to the extent, that, with suitable parametrisation and fitting to accurately known experimental data, they can be used for filling gaps in the available experimental nuclear data base as well as for bulk computations of nuclear reaction, e.g. activation cross sections. The concurrent rapid development of ever more powerful mainframe and personal computers has stimulated the development of comprehensive nuclear model computer codes. A representative selection of such codes will be presented in the lectures and computer exercises of this Workshop. In order to fulfill nuclear data requirements of the nineties and, at the same time, develop improved tools for nuclear physics teaching at developing country universities it will be required and a major future task of the IAEA nuclear data programme to develop computer files of ''best'' sets of nuclear parameters for standardised input to nuclear model computations of nuclear data. Nuclear scientists from developing countries can make substantial contributions to this project. (author). 25 refs

Nuclear reactions an introduction

CERN Document Server

Paetz gen. Schieck, Hans

2014-01-01

Nuclei and nuclear reactions offer a unique setting for investigating three (and in some cases even all four) of the fundamental forces in nature. Nuclei have been shown – mainly by performing scattering experiments with electrons, muons, and neutrinos – to be extended objects with complex internal structures: constituent quarks; gluons, whose exchange binds the quarks together; sea-quarks, the ubiquitous virtual quark-antiquark pairs and, last but not least, clouds of virtual mesons, surrounding an inner nuclear region, their exchange being the source of the nucleon-nucleon interaction.   The interplay between the (mostly attractive) hadronic nucleon-nucleon interaction and the repulsive Coulomb force is responsible for the existence of nuclei; their degree of stability, expressed in the details and limits of the chart of nuclides; their rich structure and the variety of their interactions. Despite the impressive successes of the classical nuclear models and of ab-initio approaches, there is clearly no ...

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2000-01-01

Full text: During last year the physicists of the Department of Nuclear Reactions were involved in many experiments and projects: -Low energy nuclear reactions: For the first time a heavy ion beam from the Warsaw Cyclotron C-200 was used to investigate elastic and inelastic scattering of 12 C ions from 12 C target. The experiment is a part of a long range programme devoted to study the energy dependence of the nucleus-nucleus interactions. -Multifragmentation of relativistic heavy ions: Multifragmentation reactions induced by 12 C on different heavy targets and at different energies were studied in experiments performed at Gesellschaft fuer Schwerionenforschung by the ALADIN Collaboration. These asymmetric systems were investigated in order to study the interplay between preequilibrium and equilibrium phenomena in the nuclear liquid - gas phase transition. -The structure of nucleons: A novel, two-structure description of the Roper resonance was proposed on the basis of the α-p scattering data reanalysed by means of a T-matrix formalism. -Atomic physics: Emission of the X-rays by fast heavy ions (S, Ti, Fe) as they traverse the matter (thin carbon or other light element foil) was investigated in a series of experiments performed at University of Erlangen. It was demonstrated, that the characteristic K α X-rays emitted by a heavy ion can serve as a tool for Z-value control of the ion. -Material research: Semiconductor heterostructures were investigated by means of Rutherford Back Scattering and Channeling methods using the 2 MeV α particles from the Van de Graaff accelerator ''Lech'' at the Department. The following reports present the results and major successes which were achieved in 1999. (author)

Aerosol simulation including chemical and nuclear reactions

International Nuclear Information System (INIS)

Marwil, E.S.; Lemmon, E.C.

1985-01-01

The numerical simulation of aerosol transport, including the effects of chemical and nuclear reactions presents a challenging dynamic accounting problem. Particles of different sizes agglomerate and settle out due to various mechanisms, such as diffusion, diffusiophoresis, thermophoresis, gravitational settling, turbulent acceleration, and centrifugal acceleration. Particles also change size, due to the condensation and evaporation of materials on the particle. Heterogeneous chemical reactions occur at the interface between a particle and the suspending medium, or a surface and the gas in the aerosol. Homogeneous chemical reactions occur within the aersol suspending medium, within a particle, and on a surface. These reactions may include a phase change. Nuclear reactions occur in all locations. These spontaneous transmutations from one element form to another occur at greatly varying rates and may result in phase or chemical changes which complicate the accounting process. This paper presents an approach for inclusion of these effects on the transport of aerosols. The accounting system is very complex and results in a large set of stiff ordinary differential equations (ODEs). The techniques for numerical solution of these ODEs require special attention to achieve their solution in an efficient and affordable manner. 4 refs

Status of CONRAD, a nuclear reaction analysis tool

International Nuclear Information System (INIS)

Saint Jean, C. de; Habert, B.; Litaize, O.; Noguere, G.; Suteau, C.

2008-01-01

The development of a software tool (CONRAD) was initiated at CEA/Cadarache to give answers to various problems arising in the data analysis of nuclear reactions. This tool is then characterized by the handling of uncertainties from experimental values to covariance matrices for multi-group cross sections. An object oriented design was chosen allowing an easy interface with graphical tool for input/output data and being a natural framework for innovative nuclear models (Fission). The major achieved developments are a data model for describing channels, nuclear reactions, nuclear models and processes with interface to classical data formats, theoretical calculations for the resolved resonance range (Reich-Moore) and unresolved resonance range (Hauser-Feshbach, Gilbert-Cameron,...) with nuclear model parameters adjustment on experimental data sets and a Monte Carlo method based on conditional probabilities developed to calculate properly covariance matrices. The on-going developments deal with the experimental data description (covariance matrices) and the graphical user interface. (authors)

Ionizing-radiation induced DNA double-strand breaks: A direct and indirect lighting up

International Nuclear Information System (INIS)

Vignard, Julien; Mirey, Gladys; Salles, Bernard

2013-01-01

The occurrence of DNA double-strand breaks (DSBs) induced by ionizing radiation has been extensively studied by biochemical or cell imaging techniques. Cell imaging development relies on technical advances as well as our knowledge of the cell DNA damage response (DDR) process. The DDR involves a complex network of proteins that initiate and coordinate DNA damage signaling and repair activities. As some DDR proteins assemble at DSBs in an established spatio-temporal pattern, visible nuclear foci are produced. In addition, post-translational modifications are important for the signaling and the recruitment of specific partners at damaged chromatin foci. We briefly review here the most widely used methods to study DSBs. We also discuss the development of indirect methods, using reporter expression or intra-nuclear antibodies, to follow the production of DSBs in real time and in living cells

Overview of light water/hydrogen-based low energy nuclear reactions

International Nuclear Information System (INIS)

Miley, George H.; Shrestha, Prajakti J.

2006-01-01

This paper reviews light water and hydrogen-based low-energy nuclear reactions (LENRs) including the different methodologies used to study these reactions and the results obtained. Reports of excess heat production, transmutation reactions, and nuclear radiation emission are cited. An aim of this review is to present a summary of the present status of light water LENR research and provide some insight into where this research is heading. (author)

Nuclear chemistry research of high-energy nuclear reactions at Carnegie-Mellon University, 1961--1977. Summary report

International Nuclear Information System (INIS)

Caretto, A.A. Jr.

1977-11-01

The activities and the results of research in the study of high energy nuclear reactions carried out at Carnegie Institute of Technology from 1957 to 1967 and at Carnegie-Mellon University from 1967 to 1977 are summarized. A complete list of all publications, doctoral dissertations, and reports resulting from the research of this project is also included. A major part of the report is a review of the research activities and results. The objective of the research of this project was the study of reactions initiated by projectiles of energy above about 100 MeV. The main effort was the investigation of simple nuclear reactions with the objective to deduce reaction mechanisms. These reactions were also used as probes to determine the nuclear structure of the target. In addition, a number of studies of spallation reactions were undertaken which included the determination of excitation functions and recoil properties. Recent research activities which have involved the study of pion induced reactions as well as reactions initiated by heavy ions is also discussed

Black holes will break up solitons and white holes may destroy them

International Nuclear Information System (INIS)

Akbar, Fiki T.; Gunara, Bobby E.; Susanto, Hadi

2017-01-01

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Black holes will break up solitons and white holes may destroy them

Energy Technology Data Exchange (ETDEWEB)

Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Susanto, Hadi, E-mail: hsusanto@essex.ac.uk [Department of Mathematical Sciences, University of Essex, Colchester, CO4 3SQ (United Kingdom)

2017-06-15

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Concrete alkali-silica reaction and nuclear radiation damage

International Nuclear Information System (INIS)

Ichikawa, Tsuneki

2008-01-01

The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca 2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca 2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 10 8 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

In-beam study of the rotational states in actinides after alpha-induced nuclear reactions

International Nuclear Information System (INIS)

Hardt, K.

1983-01-01

In the experiments described in this thesis the ground state rotational bands of a whole series of actinide isotopes has been studied by means of α-induced nuclear reactions. The rotational bands studied in the even isotopes could be identified up to a spin of about 16 (h/2π). With this data it was now possible to establish a broad systematic of the rotational energies up to relatively high angular momenta. Also in the odd isotopes 233 U and 239 Pu it was possible to follow the ground state rotational bands up to higher spins and to compare them with predictions of the rotational model. By means of the (α,α'2n) reaction the nuclei 230 Th and especially 228 Th could by populated. (orig./HSI) [de

Experimental studies of the break-up of 156 MeV 6Li-ions at extreme forward angles using the Karlsruhe magnetic spectrograph 'Little John'

International Nuclear Information System (INIS)

Jelitto, H.

1987-05-01

6 Li-induced break-up reactions have been investigated at reaction angles in extreme forward direction including O 0 with the Karlsruhe Magnetic Spectrograph 'Little John'. The experiments were characterized by the minimization of the high experimental background that dominates at small emission angles. Inclusive alpha-particle and deuteron spectra from the bombardement of 12 C- and 208 Pb-targets with 156 MeV 6 Li-ions have been measured. Below the grazing angle the Coulomb interaction shows a distinct influence on the angular distributions of the fragments. A simple spectator-model and a more realistic description within the DWBA-formalism largely allows a reproduction of the data. In the light of the reverse reaction α + d → 6 Li + γ at small α-d-relative energies, which is of considerable interest for astrophysics, a particle-particle-coincidence measurement with θ α = 5 0 and θ d = -2 0 has been performed. The result could be reproduced reasonably well by a simple Monte-Carlo-simulation. Beside the treatment of a physical problem this work deals with the start-up of the magnetic spectrograph and the clarification of spectrograph specific questions concerning the data reduction. (orig.) [de

Department of Nuclear Reaction - Overview

International Nuclear Information System (INIS)

Budzanowski, A.

2002-01-01

Full text: Our research in 2001 can be characterized by a wide range of various subjects e.g. search for new physics in Au + Au collisions at the energy in the centre of mass per nucleon pair √ s NN = 200 GeV through hunting dibaryon formation in p + p → K + + D (dibaryon) reaction to the application of the random matrix theory taken from nuclear reaction studies in the analysis of fluctuations of the stock exchange time and space correlations. Heavy ion reactions have been studied in a broad range of energies. At low energy of the 12 C ions (E CM = 25.57 MeV), delivered by the Warsaw U200P cyclotron, the reactions induced on 11 B target were studied. Coupling effects between various reaction channels were found. At the energies corresponding to the liquid-to-gas phase transition, the onset of the flow phenomena was found in the multifragmentation of the 197 Au nuclei induced by a sequence of projectiles p, 4 He, 12 C of the energies from 1-3 GeV per nucleon. Finally, evidence of the melting of the baryonic structure of the colliding nuclei was found at the highest available energies of 200 GeV per nucleon pair, in the collision of gold nuclei studied at the Relativistic Heavy Ion Collider within the BRAHMS and PHOBOS collaboration. We entered a new collaboration HIRES with the aim to discover S = -1 dibaryonic state by studying the reaction p+p → K + +D. So far many attempts to prove experimentally the existence of a dibaryonic state failed. We hope to use the unique properties of the Big Karl spectrometer to prove the existence of a sharp peak in the energy spectra of kaons. To do so, we have to reduce strongly the background of pions. A diffusely reflective threshold Cherenkov detector made from silica aerogel was designed. Preliminary tests indicate that pionic signals can be reduced by a factor of 58. Extensive studies of the mechanism of generating collective levels and the energy gap by means of diagonalizing matrices with random elements ended up with

Theory of vibratory mobilization and break-up of non-wetting fluids entrapped in pore constrictions

Science.gov (United States)

Beresnev, I.; Li, W.; Vigil, D.

2006-12-01

Quantitative dynamics of a non-wetting (e. g., NAPL) ganglion entrapped in a pore constriction and subjected to vibrations can be approximated by the equation of motion of an oscillator moving under the effect of the external pressure gradient, inertial oscillatory force, and restoring capillary force. The solution of the equation provides the conditions under which the droplet experiences forced oscillations without being mobilized or is liberated upon the acceleration of the wall exceeding an "unplugging" threshold. This solution provides a quantitative tool for the estimation of the parameters of vibratory fields needed to liberate entrapped non-wetting fluids. For typical pore sizes encountered in reservoirs and aquifers, wall accelerations must exceed at least several m/sec2 and even higher levels to mobilize the droplets of NAPL; however, in the populations of ganglia entrapped in natural porous environments, many may reside very near their mobilization thresholds and may be mobilized by extremely low accelerations as well. For given acceleration, lower seismic frequencies are more efficient. The ganglia may also break up into smaller pieces when passing through pore constrictions. The snap-off is governed by the geometry only; for constrictions with sinusoidal profile (spatial wavelength of L and maximum and minimum radii of rmax and rmin, the break-up occurs if L > 2π(rmin rmax)1/2. Computational fluid dynamics shows the details of the break-up process.

Dynamic screening in solar and stellar nuclear reactions

Energy Technology Data Exchange (ETDEWEB)

Daeppen, W. [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA (United States); Mussack, K. [Los Alamos National Laboratory, XTD-2, Los Alamos, NM (United States)

2012-02-15

In the hot, dense plasma of solar and stellar interiors, Coulomb potentials are screened, resulting in increased nuclear reaction rates. Although Salpeter's approximation for static screening is widely accepted and used in stellar modeling, the question of screening in nuclear reactions was revisited in the 1990s. In particular the issue of dynamic effects was raised by Shaviv and Shaviv, who applied the techniques of molecular dynamics to the conditions in the Sun's core in order to numerically determine the effect of screening. By directly calculating the motion of ions and electrons due to Coulomb interactions, the simulations are used to compute the effect of screening without the mean-field assumption inherent in Salpeter's approximation. In the last few years, the USC group has first reproduced Shaviv and Shaviv's numerical analysis of the screening energy, showing an effect of dynamic screening. When the consequence for the reaction-rate was computed, a rather surprising resulted, which is contrary to that from static screening theory. Our calculations showed that dynamic screening does not significantly change the reaction rate from that of the bare Coulomb potential. If this can be independently confirmed, then the effects of dynamic screening are highly relevant and should be included in stellar nuclear reaction rates (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Forging the link between nuclear reactions and nuclear structure.

Science.gov (United States)

Mahzoon, M H; Charity, R J; Dickhoff, W H; Dussan, H; Waldecker, S J

2014-04-25

A comprehensive description of all single-particle properties associated with the nucleus Ca40 is generated by employing a nonlocal dispersive optical potential capable of simultaneously reproducing all relevant data above and below the Fermi energy. The introduction of nonlocality in the absorptive potentials yields equivalent elastic differential cross sections as compared to local versions but changes the absorption profile as a function of angular momentum suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential to allow for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e'p) and (p, 2p) reactions are correctly incorporated, including the energy distribution of about 10% high-momentum nucleons, as experimentally determined by data from Jefferson Lab. These high-momentum nucleons provide a substantial contribution to the energy of the ground state, indicating a residual attractive contribution from higher-body interactions for Ca40 of about 0.64  MeV/A.

Ex-vacuo nuclear reaction analysis of deuterium

International Nuclear Information System (INIS)

Lee, S.R.; Doyle, B.L.

1989-01-01

A novel technique for performing in-air d( 3 He, p) nuclear reaction analysis of deuterium using external 3 He ion beams ranging in energy from 0.3-2.0 MeV is presented. Variable on-target beam energies for the depth profiling of deuterium are obtained by varying the transmission distance of the external 3 He beam in air. The ex-vacuo nuclear reaction analysis (XNRA) apparatus is described, and unique aspects and limitations of in-air depth profiling of deuterium using the d( 3 He, p) reaction are discussed. Example analyses where XNRA has been used for the multidimensional measurement of deuterium in fusion reactor components are presented in order to illustrate the advantages of XNRA for deuterium. These advantages include nondestructive analysis of large targets, efficient depth profiling via variable air gap energy tuning, and rapid analysis of numerous samples in the absence of vacuum cycling. (orig.)

Study of activation cross-sections of deuteron induced reactions on rhodium up to 40 MeV

International Nuclear Information System (INIS)

Ditroi, F.; Tarkanyi, F.; Takacs, S.; Hermanne, A.; Yamazaki, H.; Baba, M.; Mohammadi, A.; Ignatyuk, A.V.

2011-01-01

Highlights: → Excitation function measurement of deuteron induced reactions on rhodium up to 40 MeV. → Model code calculations with EMPIRE, ALICE and TALYS. → Integral production yield calculation. → Thin layer activation (TLA) with the produced isotopes. - Abstract: In the frame of a systematic study of the activation cross-sections of deuteron induced nuclear reactions, excitation functions of the 103 Rh(d,x) 100,101,103 Pd, 100g,101m,101g,102m,102g Rh and 103g Ru reactions were determined up to 40 MeV. Cross-sections were measured with the activation method using a stacked foil irradiation technique. Excitation functions of the contributing reactions were calculated using the ALICE-IPPE, EMPIRE-II and TALYS codes. From the measured cross-section data integral production yields were calculated and compared with experimental integral yield data reported in the literature. From the measured cross-sections and previous data, activation curves were deduced to support thin layer activation (TLA) on rhodium and Rh containing alloys.

RELAP/MOD1.5 analysis of steam line break transients for a 3-loop and a 4-loop Westinghouse nuclear steam supply system

International Nuclear Information System (INIS)

Peeler, G.B.; McDonald, T.A.; Kennedy, M.F.

1984-01-01

RELAP/MOD1.5 (Cycle 31 and 34) calculations were made to assess the assumptions used by Westinghouse (W) to analyze mainsteam line break transients. Models of a W 3-loop and 4-loop nuclear steam supply system were used. Sensitivity studies were performed to determine the effect of the availability of offsite power, break size and initial core power. Comparison with W results indicated that if the assumptions used by W are replicated within the RELAP5 framework, then the W methodology for prediction of the Nuclear Steam Supply System (NSSS) response is conservative for steam line break transients

The nuclear structure dependence of (p,α) reactions on light nuclei

International Nuclear Information System (INIS)

Leitner, W.

1985-01-01

As the theoretical predictions on nuclear structure and on nucleon-nucleon correlations implied by the nuclear wave functions are not subject to an immediate experimental verification the authors require a reaction theory connecting these state functions with observable quantities. The application of (rho,α) reactions as a spectroscopic tool has found widespread interest, as a number of microscopic descriptions of the reaction mechanism have facilitated the extraction of nuclear structure information. A microscopic formulation results in a strong dependence of the cross section on the nuclear structure of the reaction partners. The different basic configurations of the transferred nucleon system contribute coherently, thus causing a great sensitivity to the relative phases of the wave functions' amplitudes. A major disadvantage inherent to these microscopic theories of multinucleon-transfer reactions is based on the destruction of the transition amplitude's formal symmetry in the dynamic and in the nuclear structure part. In order to retain the factorization of the reaction amplitude, the authors applied the cluster ansatz to the microscopic theory of an earlier studies. The attractive features of this procedure are the conservation of the coherence properties of the structure term and the straightforward determination of transition strengths, independent of an elaborate DWBA treatment

Contemporaneous assembly of Western Gondwana and final Rodinia break-up: Implications for the supercontinent cycle

Directory of Open Access Journals (Sweden)

Sebastián Oriolo

2017-11-01

Full Text Available Geological, geochronological and isotopic data are integrated in order to present a revised model for the Neoproterozoic evolution of Western Gondwana. Although the classical geodynamic scenario assumed for the period 800–700 Ma is related to Rodinia break-up and the consequent opening of major oceanic basins, a significantly different tectonic evolution can be inferred for most Western Gondwana cratons. These cratons occupied a marginal position in the southern hemisphere with respect to Rodinia and recorded subduction with back-arc extension, island arc development and limited formation of oceanic crust in internal oceans. This period was thus characterized by increased crustal growth in Western Gondwana, resulting from addition of juvenile continental crust along convergent margins. In contrast, crustal reworking and metacratonization were dominant during the subsequent assembly of Gondwana. The Río de la Plata, Congo-São Francisco, West African and Amazonian cratons collided at ca. 630–600 Ma along the West Gondwana Orogen. These events overlap in time with the onset of the opening of the Iapetus Ocean at ca. 610–600 Ma, which gave rise to the separation of Baltica, Laurentia and Amazonia and resulted from the final Rodinia break-up. The East African/Antarctic Orogen recorded the subsequent amalgamation of Western and Eastern Gondwana after ca. 580 Ma, contemporaneously with the beginning of subduction in the Terra Australis Orogen along the southern Gondwana margin. However, the Kalahari Craton was lately incorporated during the Late Ediacaran–Early Cambrian. The proposed Gondwana evolution rules out the existence of Pannotia, as the final Gondwana amalgamation postdates latest connections between Laurentia and Amazonia. Additionally, a combination of introversion and extroversion is proposed for the assembly of Gondwana. The contemporaneous record of final Rodinia break-up and Gondwana assembly has major implications for the

On the theory of direct reactions with many particle final states

International Nuclear Information System (INIS)

Trautmann, D.; Baur, G.

1977-01-01

We study the theory of direct reactions with many particle final states. First, we concentrate on the DWBA formulation of the break-up of deuterons on heavy nuclei below the Coulomb barrier. Because there are no free parameters, this permits a clean test of the theory by comparing it to the experimental data. The agreement is very good. The theory is applied to the break-up of antideuteronic atoms. Then the effect of virtual deuteron break-up on Rutherford scattering is studied. It is small, but it seems to be measurable. Also the deuteron break-up above the Coulomb barrier can be well explained theoretically. In this context, small effects are studied briefly. A semiclassical theory of the break-up process is given, which results in an intuitive picture and a fast computational method. Our theory lends itself in a natural way to the study of stripping reactions to unbound states. The relation of stripping into the continuum to elastic scattering of the transferred particle on the same target nucleus is explained. Then the connection of stripping to bound and unbound states is established. Finally various examples of stripping of uncharged and charged particles into the continuum are given to illustrate the theory. Resonance wave functions describing the transferred particle are discussed. In a conclusion an outlook for possible future developments of experiment and theory is given. (author)

Towards an unified microscopic approach of the description of the nuclear structure and reaction

International Nuclear Information System (INIS)

Hoang, Sy-Than

2009-01-01

interactions. We have thus examined the structures of the different zones of the inner crust, from the lowest densities up to densities close to the vicinity of half saturation density where the spherical assumption breaks down. 3. Nuclear reactions: Using the same effective interactions derived from the M3Y-type interactions we have performed a coupled channel analysis of (p,n) charge exchange reactions at 35 and 45 MeV incident energies on 48 Ca, 90 Zr, 120 Sn and 208 Pb targets leading to isobaric analog states. The form factors are either calculated microscopically by the convolution model, or evaluated from the global optical potential taken from the literature. We have first determined the component of the CDM3Y6 interaction which depends on the isovector density by using the microscopic optical potential of Jeukenne, Lejeune and Mahaux, and then this was used for the folding model. Thus, we have been able to assess the validity of the component of CDM3Y6 which depends on the isovector density. (author)

Nuclear reaction studies using inverse kinematics

International Nuclear Information System (INIS)

Shapira, D.

1985-01-01

Reaction studies with reversed kinematics refer to studies of nuclear reactions induced by a heavy projectile colliding with lighter target nuclei. The technique of using reversed kinematics is costly in terms of the available center-of-mass energy. Most of the projectile's energy goes into forward motion of the reaction products in the laboratory system. Examples are presented where the use of reversed kinematics techniques has provided new information on certain reaction processes. A list of kinematic properties and advantages they may afford is shown. Clearly the possible studies listed can be done without using reversed kinematics but because of the difficulty associated with some of these studies they were never performed until more energetic heavier beams have become available and the reversed kinematics technique was utilized

Some parameters of uranium hexafluoride plasma produced by products of nuclear reaction

International Nuclear Information System (INIS)

Batyrbekov, G.A.; Belyakova, Eh.A.

1996-01-01

The probe experimental results of investigation of uranium hexafluoride plasma produced in the centre of nuclear reactor core were demonstrated. Study of uranium hexafluoride plasma is continued by the following reasons: a possibility of U F 6 utilization as nuclear fuel, the utilization of U F 6 as volume source o ionization, search of active laser media compatible with U F 6 that is complicated by lack of constant rates data for most of plasma-chemical reactions with U F 6 and his dissociation products. Cylindrical probe volt-ampere characteristics (VAC) measured in U F 6 plasma at pressure 20 Torr and different thermal neutron fluxes and have following features: -firstly, it is possible to choose a linear part in the field of small positive potentials of probe (0-1) V; - secondary, ion branches of VAC have typical break which current of satiation corresponds to; -thirdly, probe VAC measured at small values of thermal neutron flux density are symmetrical. Diagnostics approaches were used for interpretation VAC of probe. The values of satiation current and linear part of electron branch were calculated, and such plasma parameters as conductivity, diffusion coefficient values of positive and negative ions were determined. The resonance recharge cross section was estimated on diffusion coefficient value

A detailed test of the statistical theory of nuclear reactions

NARCIS (Netherlands)

Spijkervet, Andreas Lambertus

1978-01-01

Low-energy nuclear reactions are governed by two principal kinds of mechanisms: direct reaction mechanisms characterized by reaction times of the order of the transit time of the bombarding particle through the nucleus , and compound nucelar reaction mechanisms. The reaction times ot the latter are

Complex nuclear-structure phenomena revealed from the nuclide production in fragmentation reactions

International Nuclear Information System (INIS)

Ricciardi, M.V.; Kelic, A.; Napolitani, P.; Schmidt, K.H.; Yordanov, O.; Ignatyuk, A.V.; Rejmund, F.

2003-12-01

Complex structural effects in the nuclide production from the projectile fragmentation of 1 A GeV 238 U nuclei in a titanium target are reported. The structure seems to be insensitive to the excitation energy induced in the reaction. This is in contrast to the prominent structural features found in nuclear fission and in transfer reactions, which gradually disappear with increasing excitation energy. Using the statistical model of nuclear reactions, relations to structural effects in nuclear binding and in the nuclear level density are demonstrated. (orig.)

Hadron Cancer Therapy: Role of Nuclear Reactions

Science.gov (United States)

Chadwick, M. B.

2000-06-20

Recently it has become feasible to calculate energy deposition and particle transport in the body by proton and neutron radiotherapy beams, using Monte Carlo transport methods. A number of advances have made this possible, including dramatic increases in computer speeds, a better understanding of the microscopic nuclear reaction cross sections, and the development of methods to model the characteristics of the radiation emerging from the accelerator treatment unit. This paper describes the nuclear reaction mechanisms involved, and how the cross sections have been evaluated from theory and experiment, for use in computer simulations of radiation therapy. The simulations will allow the dose delivered to a tumor to be optimized, whilst minimizing the dos given to nearby organs at risk.

Production of Energetic Light Fragments in Spallation Reactions

Directory of Open Access Journals (Sweden)

Mashnik Stepan G.

2014-03-01

Full Text Available Different reaction mechanisms contribute to the production of light fragments (LF from nuclear reactions. Available models cannot accurately predict emission of LF from arbitrary reactions. However, the emission of LF is important formany applications, such as cosmic-ray-induced single event upsets, radiation protection, and cancer therapy with proton and heavy-ion beams, to name just a few. The cascade-exciton model (CEM and the Los Alamos version of the quark-gluon string model (LAQGSM, as implemented in the CEM03.03 and LAQGSM03.03 event generators used in the Los Alamos Monte Carlo transport code MCNP6, describe quite well the spectra of fragments with sizes up to 4He across a broad range of target masses and incident energies. However, they do not predict high-energy tails for LF heavier than 4He. The standard versions of CEM and LAQGSM do not account for preequilibrium emission of LF larger than 4He. The aim of our work is to extend the preequilibrium model to include such processes. We do this by including the emission of fragments heavier than 4He at the preequilibrium stage, and using an improved version of the Fermi Break-up model, providing improved agreement with various experimental data.

Nuclear targets, recoil ion catchers and reaction chambers

NARCIS (Netherlands)

Dionisio, JS; Vieu, C; Schuck, C; Collatz, R; Meunier, R; Ledu, D; Folger, H; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Blunt, D; Durell, JL; Varley, BJ; Dagnall, PG; Dorning, SJ; JONES, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Amzal, N; Meliani, Z; Vanhorenbeeck, J; Passoja, A; Urban, W

1998-01-01

The main features of nuclear targets, recoil ion catchers and reaction chambers used in nuclear spectroscopic investigations involving in-beam multi-e-gamma spectrometers are discussed. The relative importance of the F-ray background due to the accelerated ion-target and the recoil-ion-target

Simulation of condensation and liquid break-up on a micro-object with upper and lower movable walls using Lattice Boltzmann Method

Science.gov (United States)

Asadollahi, Arash; Esmaeeli, Asghar

2018-05-01

In this paper, two-dimensional condensation, liquid behavior on the micro-object with moving walls, and breaking up have been investigated by the Shan and Chen multiphase Lattice Boltzmann Method (LBM), which has the ability to incorporate interactions such as fluid-fluid, and also fluid-solid. Four test cases with low, medium, high, and very high Weber numbers are investigated considering the velocity control of walls in detail. Vertical spread fraction n / h (where n is the minimum liquid thickness after deformation and h is the maximum length of liquid deformation in each time) decreases quickly indicating the liquid tendency to breakup in all cases. Except for the case of a very high Weber number, the separation will not happen and finally after fluctuation the fixed bulk of condensed liquid will be placed on the side of the micro-object. The maximum value of reaction parameter h / d becomes larger as the Weber number increases. It is shown that an increase in the Weber number leads to liquid breakup and this mechanism provides an effective way for removing the condensed liquid from micro-devices surfaces. The results by LBM reveal the liquid evolutionary behavior and breaking up over time and show that it is a controllable situation by manipulating the walls velocity. Moreover, it can be used in order to centralize and aggregate all the liquid to a specific direction.

Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy

International Nuclear Information System (INIS)

D'Enterria, D.G.

2000-05-01

The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (E γ > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar 36 + Au 197 , Ag 107 , Ni 58 , C 12 at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4π. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pnγ) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

Light ion reaction mechanisms and nuclear structure

International Nuclear Information System (INIS)

Robson, B.A.

1986-01-01

Of the many contributions to the subject 'Light ion reaction mechanism and nuclear structure', a few are selected and reviewed which highlight the present state of the field. Some contributions to the conference dealing with nuclear interactions are briefly outlined in the second section following an introductory section. Lane model calculations are compared with data for 9 Be and results are given showing angular distributions of the cross sections, the analyzing powers and the spin-rotation parameters for p - 40 Ca. Real central potential for d + 32 s resulting from the FB-analysis are compared with frozen density folding and delta-function folding. The third section deals with reaction mechanism. Data are cited which show near-side and far-side contributions to the calculated analyzing powers in the 116 Sn(d,p) 117 Sn (11.2 - ) transition. Calculations are compared with experimental A y and -(A yy + 2)/3. Also given are measurements of the cross sections and analyzing powers of the continuum energy spectra for the 58 Ni(p,p'x), along with relations between the analyzing powers and momentum transfer. The fourth section addresses nuclear structure. Cross sections and analyzing powers measured at 22 MeV for the reaction 208 Pb(p,t) 206 Pb(3 2 + ) are cited and considered. (Nogami, K.)

Images of mycobacterium for nuclear reactions

International Nuclear Information System (INIS)

Lima, C.T.S.; Crispim, V.R.; Silva, M.G.

2007-01-01

According to the World Health Organization (WHO) tuberculosis is responsible for 2.9 million deaths annually worldwide. The necessity for optimizing time to detect the tuberculosis bacillus (mycobacterium tuberculosis) in the sputum samples of affected individuals (TB patients) led to the development of a methodology based on the doping with boron of the bacillus, submission of the samples to thermal neutron beam and ionizing particles, generating nuclear reactions of the types: 10 B (n,α) 7 Li and 10 B(α, p) 13 C. Images of these bacilli are obtained by means of the nuclear tracks produced in the CR-39 detector for particles products of these nuclear reactions, α and p. When the CR-39 is submitted to a chemical attack the traces are developed and the images of the microorganisms registered in the detector can be observed with a conventional light microscope, characterizing them by morphology. The use of this methodology results in images of the mycobacterium tuberculosis becoming more defined and enlarged than those obtained by bacilloscopy, in which the sample is submitted to the method of coloration of Ziehl-Neelsen (ZN) and observed in light microscopy. (author)

Sunflower oil ozonation. Following of the reaction by proton Nuclear Magnetic Resonance

International Nuclear Information System (INIS)

Diaz Gomez, Maritza F.

2005-01-01

Previous studies have demonstrated that the technique of Proton Nuclear Magnetic Resonance can be used for the pursuit of the reaction between the ozone and the unsaturated fatty acids. It's carried out the sunflower oil ozonization to different applied dose of ozone and the index of peroxides and the concentration of aldehydes are determined. The main reaction products were identified by Proton Nuclear Magnetic Resonance Spectroscopy (NMR 1 H). The intensities of the signs were used to follow the advance of the reaction between the ozone and the sunflower oil. It is was carried out until obtaining an index of peroxides of 1 202 mmol-equiv/kg. The intensities of the signs of the olefinic protons diminish with a gradual increment in the dose of applied ozone, but without ending up disappearing completely. The ozonides of Criegee obtained to applied dose of ozone of 107,1 mg/g were approximately bigger 7,4 times that those obtained at the beginning from the reaction to applied dose of ozone of 15,3 mg/g. The aldehydes protons were observed as a sign of weak intensity in all the spectra. The signs belonging to the olenifics protons of the hydroperoxides in d = 5,55 ppm increases with the increment of the applied dose of ozone. You concludes that to higher applied dose of ozone, haggler is the advance of the ozonization reaction, what belongs together with a bigger formation of oxygenated compounds

Direct nuclear reactions and the structure of atomic nuclei

International Nuclear Information System (INIS)

Osterfeld, F.

1985-01-01

The present thesis deals with two different aspects of direct nuclear reactions, namely on the one hand with the microscopic calculation of the imaginary optical potential for the elastic nucleon-nucleus scattering as well as on the other hand with the microscopic analysis of giant magnetic resonances in atomic nuclei which are excited by (p,n) charge-exchange reactions. In the first part of the thesis the imaginary part of the optical potential for the elastic proton- and neutron-nucleus scattering is microscopically calculated in the framework of the so called nuclear-structure approximation to the optical potential. The calculations are performed in the Feshbach formalism in second-order perturbation theory corresponding to an effective projectile-target-nucleon interaction. In the second part of this thesis in the framework of microscopic nuclear models a complete analysis of different A(p,n)B charge-exchange reactions at high incident energies 160 MeV 90 Zr(p,n) reaction three collective spin-isospin resonances could be uniquely identified. (orig./HSI) [de

Analysis of the proton-induced reactions at 150 MeV - 24 GeV by high energy nuclear reaction code JAM

International Nuclear Information System (INIS)

Niita, Koji; Nara, Yasushi; Takada, Hiroshi; Nakashima, Hiroshi; Chiba, Satoshi; Ikeda, Yujiro

1999-09-01

We are developing a nucleon-meson transport code NMTC/JAM, which is an upgraded version of NMTC/JAERI. NMTC/JAM implements the high energy nuclear reaction code JAM for the infra-nuclear cascade part. By using JAM, the upper limits of the incident energies in NMTC/JAERI, 3.5 GeV for nucleons and 2.5 GeV for mesons, are increased drastically up to several hundreds GeV. We have modified the original JAM code in order to estimate the residual nucleus and its excitation energy for nucleon or pion induced reactions by assuming a simple model for target nucleus. As a result, we have succeeded in lowering the applicable energies of JAM down to about 150 MeV. In this report, we describe the main components of JAM code, which should be implemented in NMTC/JAM, and compare the results calculated by JAM code with the experimental data and with those by LAHET2.7 code for proton induced reactions from 150 MeV to several 10 GeV. It has been found that the results of JAM can reproduce quite well the experimental double differential cross sections of neutrons and pions emitted from the proton induced reactions from 150 MeV to several 10 GeV. On the other hand, the results of LAHET2.7 show the strange behavior of the angular distribution of nucleons and pions from the reactions above 4 GeV. (author)

Excitation functions of proton induced nuclear reactions on {sup nat}Fe up to 16 MeV, with emphasis on radiochemical determination of low cross sections

Energy Technology Data Exchange (ETDEWEB)

Uddin, Md. Shuza [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Neurowissenschaften und Medizin (INM), Nuklearchemie (INM-5); Atomic Energy Research Establishment, Dhaka (Bangladesh). Tandem Accelerator Facilities; Chakraborty, Animesh Kumer [Chittagong Univ. of Engineering and Technology (Bangladesh). Dept. of Physics; Atomic Energy Research Establishment, Dhaka (Bangladesh). Tandem Accelerator Facilities; Spellerberg, Stefan; Spahn, Ingo; Qaim, Syed M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Neurowissenschaften und Medizin (INM), Nuklearchemie (INM-5); Shariff, Md. Asad [Atomic Energy Research Establishment, Dhaka (Bangladesh). Tandem Accelerator Facilities; Rashid, Md. Abdur [Chittagong Univ. of Engineering and Technology (Bangladesh). Dept. of Physics

2017-07-01

Excitation functions for the formation of the radionuclides {sup 56}Co, {sup 57}Co, {sup 58m+g}Co and {sup 54}Mn via proton induced reactions on natural iron target were measured from their respective thresholds up to 16 MeV using the stacked-foil activation technique and HPGe detector γ-ray spectroscopy. In the threshold energy range, the low cross sections for {sup 54}Mn were measured radiochemically. All the measured values were compared with available experimental data and with theoretical calculations reproduced in TENDL-2015 nuclear data library. New data for the formation of {sup 57}Co, {sup 58}Co and {sup 54}Mn were obtained near their reaction thresholds. Other data obtained strengthen the database. Polynomial fittings of the data measured in this work as well as of all data sets (including the present data) were performed. The present data appear to be closer to theoretical calculations than the literature data.

Activation cross-sections of deuteron induced nuclear reactions on manganese up to 40 MeV

International Nuclear Information System (INIS)

Ditroi, F.; Tarkanyi, F.; Takacs, S.; Hermanne, A.; Yamazaki, H.; Baba, M.; Mohammadi, A.; Ignatyuk, A.V.

2011-01-01

In the frame of a systematic study on activation cross-sections of deuteron induced reactions experimental excitation functions on 55 Mn were measured with the activation method using the stacked foil irradiation technique up to 40 MeV. By using high resolution γ-ray spectrometry, cross-section data for the production of 56,54,52 Mn and 51 Cr were determined. Comparison with the earlier published data and with the results predicted by the ALICE-IPPE and EMPIRE-II theoretical codes - improved for more reliable calculations for d-induced reactions - and with data in the TENDL 2010 libraries are also included. Thick target yields were calculated from a fit to our experimental excitation curves and implications for practical applications in industrial (Thin Layer Activation) accelerator technology are discussed.

[Electromagnetic studies of nuclear structure and reactions

International Nuclear Information System (INIS)

1992-01-01

The experimental goals are focused on developing an understanding of strong interactions and the structure of hadronic systems by determination of the electromagnetic response; these goals will be accomplished through coincidence detection of final states. Nuclear modeling objectives are to organize and interpret the data through a consistent description of a broad spectrum of reaction observables; calculations are performed in a nonrelativistic diagrammatic framework as well as a relativistic QHD approach. Work is described according to the following arrangement: direct knockout reactions (completion of 16 O(e,e'p), 12 C(e,e'pp) progress, large acceptance detector physics simulations), giant resonance studies (intermediate-energy experiments with solid-state detectors, the third response function in 12 C(e,e'p 0 ) and 16 O(e,e'p 0 ), comparison of the 12 C(e, e'p 0 ) and 16 O(e,e'p 3 ) reactions, quadrupole strength in the 16 O(e,e'α 0 ) reaction, quadrupole strength in the 12 C(e,e'α) reaction, analysis of the 12 C(e,e'p 1 ) and 16 O(e,e'p 3 ) angular distributions, analysis of the 40 Ca(e,e'x) reaction at low q, analysis of the higher-q 12 C(e,e'x) data from Bates), models of nuclear structure (experimental work, Hartree-Fock calculations, phonon excitations in spherical nuclei, shell model calculations, variational methods for relativistic fields), and instrumentation development efforts (developments at CEBAF, CLAS contracts, BLAST developments)

Flocculation and floc break-up related to tidally induced turbulent shear in a low-turbidity, microtidal estuary

DEFF Research Database (Denmark)

Markussen, Thor Nygaard; Andersen, Thorbjørn Joest

2014-01-01

flocculation and floc break-up dynamics in the lower part of the water column in the period around slack water. These dynamics were confirmed in the Eulerian deployments and were reoccurring in every tidal cycle. The dynamics were mostly governed by changes in turbulent shear. Strong microflocs with a lower...... mean threshold diameter of 50–60 μm present at high turbulent shear flocculated to form fragile macroflocs with sizes of several hundred microns and mean diameters above 80 μm around slack water periods. A hysteresis in floc break-up and flocculation was found at high water slack (HWS), as flocs formed...

Pre-equilibrium nuclear reactions: An introduction to classical and quantum-mechanical models

International Nuclear Information System (INIS)

Koning, A.J.; Akkermans, J.M.

1999-01-01

In studies of light-ion induced nuclear reactions one distinguishes three different mechanisms: direct, compound and pre-equilibrium nuclear reactions. These reaction processes can be subdivided according to time scales or, equivalently, the number of intranuclear collisions taking place before emission. Furthermore, each mechanism preferably excites certain parts of the nuclear level spectrum and is characterized by different types of angular distributions. This presentation includes description of the classical, exciton model, semi-classical models, with some selected results, and quantum mechanical models. A survey of classical versus quantum-mechanical pre-equilibrium reaction theory is presented including practical applications

On nuclear reaction duration at the range of overlapping resonances

International Nuclear Information System (INIS)

Olkhovsky, V.S.

1981-01-01

Nuclear reaction duration above the threshold of overlapping resonances is investigated and its importance to obtain a new information on a collision mechanism is evidenced. It is shown also that the duration of resonant nuclear reactions is asymptotically decreasing according to the law[E 2 n(E)] -1 when the energy E and the number of open channels n(E) are increasing [ru

The build-up and characterization of nuclear burn-up wave in a fast ...

Indian Academy of Sciences (India)

K V Anoop

2018-02-07

Feb 7, 2018 ... evaluating the quality of the wave by the researchers working in the field of nuclear burn-up wave build-up and propagation. Keywords. ... However, there are concerns relating to the nuclear safety, ... Simulation studies have.

Nuclear Forensics and Radiochemistry: Reaction Networks

Energy Technology Data Exchange (ETDEWEB)

Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-22

In the intense neutron flux of a nuclear explosion the production of isotopes may occur through successive neutron induced reactions. The pathway to these isotopes illustrates both the complexity of the problem and the need for high quality nuclear data. The growth and decay of radioactive isotopes can follow a similarly complex network. The Bateman equation will be described and modified to apply to the transmutation of isotopes in a high flux reactor. A alternative model of growth and decay, the GD code, that can be applied to fission products will also be described.

Low Energy Nuclear Reactions?

CERN Multimedia

CERN. Geneva; Faccini, R.

2014-01-01

After an introduction to the controversial problem of Low Energy Nuclear Reactions (LENR) catalyzed by neutrons on metallic hydride surfaces we present the results of an experiment, made in collaboration with ENEA Labs in Frascati, to search neutrons from plasma discharges in electrolytic cells. The negative outcome of our experiment goes in the direction of ruling out those theoretical models expecting LENR to occur in condensed matter systems under specific conditions. Our criticism on the theoretical foundations of such models will also be presented.

Nuclear reaction studies: Progress report

International Nuclear Information System (INIS)

Thaler, R.M.

1986-01-01

A principal focus of recent research has been the three-body problem. A great deal of effort has been devoted to the creation of a computer program to calculate physical observables in the three body problem below 1 GeV. Successful results have been obtained for the triton. Additional work concerns scattering of K + mesons from nuclei, antinucleon physics, relativistic nuclear physics and inclusive reactions

Quasielastic reactions

International Nuclear Information System (INIS)

Henning, W.

1979-01-01

Quasielastic reaction studies, because of their capability to microscopically probe nuclear structure, are still of considerable interest in heavy-ion reactions. The recent progress in understanding various aspects of the reaction mechanism make this aim appear closer. The relation between microscopic and macroscopic behavior, as suggested, for example, by the single proton transfer data to individual final states or averaged excitation energy intervals, needs to be explored. It seems particularly useful to extend measurements to higher incident energies, to explore and understand nuclear structure aspects up to the limit of the energy range where they are important

Development of a utility system for nuclear reaction data file: WinNRDF

International Nuclear Information System (INIS)

Aoyama, Shigeyoshi; Ohbayasi, Yosihide; Masui, Hiroshi; Chiba, Masaki; Kato, Kiyoshi; Ohnishi, Akira

2000-01-01

A utility system, WinNRDF, is developed for charged particle nuclear reaction data of NRDF (Nuclear Reaction Data File) on the Windows interface. By using this system, we can easily search the experimental data of a charged particle nuclear reaction in NRDF than old retrieval systems on the mainframe and also see graphically the experimental data on GUI (Graphical User Interface). We adopted a mechanism of making a new index of keywords to put to practical use of the time dependent properties of the NRDF database. (author)

Direct nuclear reaction experiments for stellar nucleosynthesis

International Nuclear Information System (INIS)

Cherubini, S.

2016-01-01

During the last two decades indirect methods where proposed and used in many experiments in order to measure nuclear cross sections between charged particles at stellar energies. These are among the lowest to be measured in nuclear physics. One of these methods, the Trojan Horse method, is based on the Quasi- Free reaction mechanism and has proved to be particularly flexible and reliable. It allowed for the measurement of the cross sections of various reactions of astrophysical interest using stable beams. The use and reliability of indirect methods become even more important when reactions induced by Radioactive Ion Beams are considered, given the much lower intensity generally available for these beams. The first Trojan Horse measurement of a process involving the use of a Radioactive Ion Beam dealt with the "1"8F(p,α)"1"5O process in Nova conditions. To obtain pieces of information on this process, in particular about its cross section at Nova energies, the Trojan Horse method was applied to the "1"8F(d,α "1"5O)n three body reaction. In order to establish the reliability of the Trojan Horse method approach, the Treiman-Yang criterion is an important test and it will be addressed briefly in this paper.

Breaking Up is Hard to Do: The Ups and Downs of Divorcing Brands

Directory of Open Access Journals (Sweden)

Fournier Susan

2014-05-01

Full Text Available Relationships with brands are like relationships between people. Even when they were very close, they can fail for diverse reasons. The disadoption of favorite brands doesn't happen overnight. It tends to be an extended, often painful process and not a clear-cut, one-off event. Breakups are not isolated to the person and the brand. Friends and family often get involved and offer their opinions and advice. Other brand relationships are also affected by the disconnection, and this can speed up or delay the process of breaking up. The brand relationship changes its form and can go from being a best friend to a platonic love, a distant friend, a stalker or even an enemy. A breakup is never the end of the relationship. Rather, it redefines the relationship and is part of a never-ending cycle of change. If the former relationship is perceived positively, it is easier to eventually activate and intensify it. If negative aspects prevail, negative word of mouth is a danger and companies must be able to counter it. Some relationships reach a point of no return. But there are also customers who might regret having abandoned a brand. With some sensitivity, it might be possible to win them back.

BNL325 - Nuclear reaction data display program

International Nuclear Information System (INIS)

Dunford, C.L.

1994-01-01

A computer code for the graphical display of nuclear reaction data is described. The code, which works on a computer with VMS operating system, can overlay experimental data from an EXFOR/CSISRS table-computation format with evaluated data from ENDF formatted data libraries. Originally, this code has been used at the U.S. National Nuclear Data Center to produce the well-known neutron cross-section atlas published as report BNL-325. (author). 3 tabs

BNL325 - Nuclear reaction data display program

Energy Technology Data Exchange (ETDEWEB)

Dunford, C L

1994-11-27

A computer code for the graphical display of nuclear reaction data is described. The code, which works on a computer with VMS operating system, can overlay experimental data from an EXFOR/CSISRS table-computation format with evaluated data from ENDF formatted data libraries. Originally, this code has been used at the U.S. National Nuclear Data Center to produce the well-known neutron cross-section atlas published as report BNL-325. (author). 3 tabs.

Probing the nuclear symmetry energy at high densities with nuclear reactions

Science.gov (United States)

Leifels, Y.

2017-11-01

The nuclear equation of state is a topic of highest current interest in nuclear structure and reactions as well as in astrophysics. The symmetry energy is the part of the equation of state which is connected to the asymmetry in the neutron/proton content. During recent years a multitude of experimental and theoretical efforts on different fields have been undertaken to constraint its density dependence at low densities but also above saturation density (ρ_0=0.16 fm ^{-3} . Conventionally the symmetry energy is described by its magnitude S_v and the slope parameter L , both at saturation density. Values of L = 44 -66MeV and S_v=31 -33MeV have been deduced in recent compilations of nuclear structure, heavy-ion reaction and astrophysics data. Apart from astrophysical data on mass and radii of neutron stars, heavy-ion reactions at incident energies of several 100MeV are the only means do access the high density behaviour of the symmetry energy. In particular, meson production and collective flows upto about 1 AGeV are predicted to be sensitive to the slope of the symmetry energy as a function of density. From the measurement of elliptic flow of neutrons with respect to charged particles at GSI, a more stringent constraint for the slope of the symmetry energy at supra-saturation densities has been deduced. Future options to reach even higher densities will be discussed.

Some general features of alpha-particle pick-up reactions

International Nuclear Information System (INIS)

Becchetti, F.D.; Jaenecke, J.

1982-01-01

The general features of single- and multi-α transfer reactions are discussed. While there are numerous difficulties in extracting α-particle ''spectroscopic'' factors, the reduced α-widths extracted appear to be meaningful. These can be related, in an absolute fashion, to α-decay widths (or α-decay lifetimes). Simpler theories describing α-particle transfer reactions are needed and should be formulated in terms of α-widths, i.e. α-particle densities in the nuclear periphery. These are the quantities measured in most experiments. IBA and SU 3 models appear to be most relevant and should be extended to α-transfer reactions for heavy nuclei. (Auth.)

Corrosion in nuclear power plants and it implication in the leak before break criteria

International Nuclear Information System (INIS)

Martinez M, E.

1992-05-01

The corrosion in a general way can be defined like a chemical or electrochemical reaction, which is carried out in the surface of the metallic materials exposed to a specific medium. Due to the operation conditions in the nuclear power plants are practically fixed and its modification in most of the cases is difficult or expensive, the natural tendency to prevent the corrosion has been generally directed toward the selection of materials. Numerous materials have been employees as substitute of the traditional steels, among other the stabilized stainless steels, those of extra low carbon and numerous nickel base alloys. The basic evaluation that establishes the approach Leak before break (LBB) it involves the analysis by means of 'fracture mechanics' of a postulated crevice that it crosses the thickness of the material, which causes a same flight, with a margin of safety, to the detection limit that it has for a shutdown of the reactor. Due to the crevice size postulated, it cannot be established highly starting from the mechanical properties of the material since these its will be affected by the corrosion mechanisms that can settle down, it was determined that the implementation of the LBB criteria, it cannot be established for components or systems that its are susceptible of suffering corrosion. (Author)

High-spin nuclear target of 178m2Hf: creation and nuclear reaction studies

International Nuclear Information System (INIS)

Oganessyan, Yu.Ts.; Karamyan, S.A.; Gangrskij, Yu.P.

1993-01-01

A long-lived (31 years) four-quasiparticle isomer 178m 2 Hf(I,K π =16,16 + ) was produced in microweight quantities using the nuclear reaction 176 Yb( 4 He, 2n). Methods of precision chemistry and mass-separation for the purification of the produced Hf material have been developed. Thin targets of isomeric hafnium-178 on carbon backings were prepared and used in experiments on a neutron, proton and deuteron beams. First results on nuclear reactions on a high-spin exotic target were obtained. Experiments on electromagnetic interactions of the isomeric hafnium using methods of the collinear laser spectroscopy as well as of the nuclear orientation of hafnium implanted into a crystalline media were started. 11 refs.; 11 figs.; 2 tabs

Probing properties of neutron stars with terrestrial nuclear reactions

International Nuclear Information System (INIS)

Li Baoan; Chen Liewen; Ko, C.M.; Steiner, Andrew W.; Yong Gaochan

2006-01-01

Heavy-ion reactions induced by neutron-rich nuclei provide the unique opportunity in terrestrial laboratories to constrain the nuclear symmetry energy Esym in a broad density range. A conservative constraint, 32(ρ/ρ0)0.7 < Esym(ρ) < 32(ρ/ρ0)1.1, around the nuclear matter saturation density ρ0 has recently been obtained from analyzing the isospin diffusion data within a transport model for intermediate energy heavy-ion reactions. This subsequently puts a stringent constraint on properties of neutron stars, especially their radii and cooling mechanisms

The US nuclear reaction data network. Summary of the first meeting, March 13 ampersand 14 1996

International Nuclear Information System (INIS)

1996-03-01

The first meeting of the US Nuclear Reaction Data Network (USNRDN) was held at the Colorado School of Mines, March 13-14, 1996 chaired by F. Edward Cecil. The Agenda of the meeting is attached. The Network, its mission, products and services; related nuclear data and data networks, members, and organization are described in Attachment 1. The following progress reports from the members of the USNRDN were distributed prior to the meeting and are given as Attachment 2. (1) Measurements and Development of Analytic Techniques for Basic Nuclear Physics and Nuclear Applications; (2) Nuclear Reaction Data Activities at the National Nuclear Data Center; (3) Studies of nuclear reactions at very low energies; (4) Nuclear Reaction Data Activities, Nuclear Data Group; (5) Progress in Neutron Physics at Los Alamos - Experiments; (6) Nuclear Reaction Data Activities in Group T2; (7) Progress Report for the US Nuclear Reaction Data Network Meeting; (8) Nuclear Astrophysics Research Group (ORNL); (9) Progress Report from Ohio University; (10) Exciton Model Phenomenology; and (11) Progress Report for Coordination Meeting USNRDN

Empire-3.2 Malta. Modular System for Nuclear Reaction Calculations and Nuclear Data Evaluation. User's Manual

International Nuclear Information System (INIS)

Herman, M.; Capote, R.; Sin, M.

2013-08-01

EMPIRE is a modular system of nuclear reaction codes, comprising various nuclear models, and designed for calculations over a broad range of energies and incident particles. The system can be used for theoretical investigations of nuclear reactions as well as for nuclear data evaluation work. Photons, nucleons, deuterons, tritons, helions ( 3 He), α's, and light or heavy ions can be selected as projectiles. The energy range starts just above the resonance region in the case of a neutron projectile, and extends up to few hundred MeV for heavy ion induced reactions. The code accounts for the major nuclear reaction models, such as optical model, Coupled Channels and DWBA (ECIS06 and OPTMAN), Multi-step Direct (ORION + TRISTAN), NVWY Multi-step Compound, exciton model (PCROSS), hybrid Monte Carlo simulation (DDHMS), and the full featured Hauser-Feshbach model including width fluctuations and the optical model for fission. Heavy ion fusion cross section can be calculated within the simplified coupled channels approach (CCFUS). A comprehensive library of input parameters based on the RIPL-3 library covers nuclear masses, optical model parameters, ground state deformations, discrete levels and decay schemes, level densities, fission barriers, and γ-ray strength functions. Effects of the dynamic deformation of a fast rotating nucleus can be taken into account in the calculations (BARFIT, MOMFIT). The results can be converted into the ENDF-6 format using the accompanying EMPEND code. Modules of the ENDF Utility Codes and the ENDF Pre-Processing codes are applied for ENDF file verification. The package contains the full EXFOR library of experimental data in computational format C4 that are automatically retrieved during the calculations. EMPIRE contains the resonance module that retrieves data from the electronic version of the Atlas of Neutron Resonances by Mughabghab (not provided with the EMPIRE distribution), to produce resonance section and related covariances for the

Charged-particle transfer reactions and nuclear astrophysics problems

International Nuclear Information System (INIS)

Artemov, S.V.; Yarmukhamedov, R.; Yuldashev, B.S.; Burtebaev, N.; Duysebaev, A.; Kadyrzhanov, K.K.

2002-01-01

In the report a review of the recent results of calculation of the astrophysical S-factors S(E) for the D(α, γ) 6 Li, 3 He(α, γ) 7 Be, 7 Be(p, γ) 8 Be, 12,13 C(p, γ) 13, 14 N and 12 C(p,γ) 16 O* reactions at extremely low energies E, including value E=0 , performed within the framework of a new method taking into account the additional information about the nuclear vertex constant (Nc) (or the respective asymptotic normalization coefficient) are presented. The required values of Nc can be obtained from an analysis of measured differential cross-sections of proton and α-particle transfer reactions (for example A( 3 He,d)B, 6 Li(d, 6 Li)d, 6 Li(α, 6 Li)α, 12 C( 6 Li, d) 16 O* etc.). A comparative analysis between the results obtained by different authors is also done. Taking into account an important role of the NVC's values for the nuclear astrophysical A(p, γ)B and A(α, γ)B reactions, a possibility of obtaining the reliable NVC values for the virtual decay B→A+p and B→A+α from the analysis of differential cross sections both sub- and above-barrier A( 3 He, d) and A( 6,7 Li, 2,3 H)B reactions is discussed in detail. In this line the use the isochronous cyclotron U-150 M, the 'DC-60' heavy ion machine and electrostatic charge-exchanging accelerator UKP-2-1 of Institute of Nuclear Physics of National Nuclear Center of the Republic of Kazakhstan for carrying out the needed experiments is considered and the possibility of the obtained data application for the astrophysical interest is also discussed

Oxygen depth profiling using the 16O(d,α)14N nuclear reaction

International Nuclear Information System (INIS)

Khubeis, I.; Al-Rjob, R.

1997-01-01

The excitation function of the 16 O(d,α) 14 N nuclear reaction has been determined in the deuteron energy range of 0.88-2.28 MeV. Major resonances are observed at deuteron energies of 0.98, 1.31, 1.53, 1.60, 1.73 and 2.22 MeV. The present results show good agreement with those of Haase and Khubeis, however there is a shift of 60 keV in the first resonance compared with the measurements of Amsel. The use of a thin surface barrier detector (t=22 μm) and a bias voltage of +20 V coupled with a proper pile-up rejection circuit has allowed the determination of the oxygen depth profiling to a resolution of 16 nm for thick targets. This method is efficient in eliminating interferences from other nuclear reactions such as 16 O(d,p) 17 O and 12 C(d,p) 19 C, where emitted protons have severely obscured α-particles from the 16 O(d,α) 14 N reaction. A 1.08 MeV deuteron beam has been employed to increase the α-yield from the target. The target has been tilted at 70 to enhance depth resolution. This reaction is well suited for the determination of oxygen concentration in oxides of high temperature superconductors. (orig.)

Experimental characterization of the spreading and break-up of liquid flat-fan sheets discharging in a low-density atmosphere and application to BrLi solutions

Energy Technology Data Exchange (ETDEWEB)

Palacios, E. [Universidad Politecnica de Madrid (Spain). Departamento de Mecanica Industrial; Nogueira, J.; Rodriguez, P.A.; Lecuona, A. [Universidad Carlos III de Madrid (Spain). Departamento de Ingenieria Termica y de Fluidos

2009-02-15

This work presents and characterizes the existence of two different regimes in the spreading and break-up of liquid flat-fan sheets when discharging in low-density atmospheres. The motivation of the study is the improvement on the absorption phenomena of lithium bromide aqueous solution when discharging in a 600-1,500 Pa water vapor environment. This corresponds to the absorber conditions in current absorption closed-cycle cooling machines. Despite this, the dimensionless characterization obtained has universal validity. The conditions that define the change in the break-up regime, the dimensionless sheet break-up length and the break-up time are given as a function of the parameters involved. Digital particle tracking velocimetry (PTV) has been applied to measure the velocity field and additional visualization techniques have been used to further characterize the break-up process. The experiments verify the existence of critical gas-to-liquid density and viscosity ratios below which gas to liquid interaction becomes negligible. The article also offers expressions that define their values as a function of the other dimensionless parameters. (orig.)

Nuclear reaction matrix and nuclear forces

International Nuclear Information System (INIS)

Nagata, Sinobu; Bando, Hiroharu; Akaishi, Yoshinori.

1979-01-01

An essentially exact method of solution is presented for the reaction- matrix (G-matrix) equation defined with the orthogonalized plane-wave intermediate spectrum for high-lying two-particle states. The accuracy is examined for introduced truncations and also in comparison with the Tsai-Kuo and Sauer methods. Properties of the G-matrix are discussed with emphasis on the relation with the saturation mechanism, especially overall saturation from light to heavy nuclei. Density and starting-energy dependences of the G-matrix are separately extracted and discussed. It is demonstrated that the triplet-even tensor component of the nuclear force is principally responsible for these dependences and hence for the saturation mechanism. In this context different nuclear potentials are used in the renormalized Brueckner calculation for energies of closed-shell nuclei in the harmonic oscillator basis. A semi-phenomenological ''two-body potential'' is devised so that it can reproduce the saturation energies and densities of nuclear matter and finite nuclei in the lowest-order Brueckner treatment. It is composed of a realistic N-N potential and two additional parts; one incorporates the three-body force effect and the other is assumed to embody higher-cluster correlations in G. The tensor component in the triplet-even state of this potential is enhanced by the three-body force effect. The G-matrix is represented in the effective local form and decomposed into central, LS and tensor components. (author)

Enhancement Mechanisms of Low Energy Nuclear Reactions

OpenAIRE

Gareev, F. A.; Zhidkova, I. E.

2005-01-01

The review of possible stimulation mechanisms of LENR (low energy nuclear reaction) is represented. We have concluded that transmutation of nuclei at low energies and excess heat are possible in the framework of the modern physical theory - the universal resonance synchronization principle [1] and based on its different enhancement mechanisms of reaction rates are responsible for these processes [2]. The excitation and ionization of atoms may play role as a trigger for LENR. Superlow energy o...

High energy gamma-ray production in nuclear reactions

International Nuclear Information System (INIS)

Pinston, J.A.; Nifenecker, H.; Nifenecker, H.

1989-01-01

Experimental techniques used to study high energy gamma-ray production in nuclear reactions are reviewed. High energy photon production in nucleus-nucleus collisions is discussed. Semi-classical descriptions of the nucleus-nucleus gamma reactions are introduced. Nucleon-nucleon gamma cross sections are considered, including theoretical aspects and experimental data. High energy gamma ray production in proton-nucleus reactions is explained. Theoretical explanations of photon emission in nucleus-nucleus collisions are treated. The contribution of charged pion currents to photon production is mentioned

Formation of droplets and bubbles in a microfluidic T-junction-scaling and mechanism of break-up.

Science.gov (United States)

Garstecki, Piotr; Fuerstman, Michael J; Stone, Howard A; Whitesides, George M

2006-03-01

This article describes the process of formation of droplets and bubbles in microfluidic T-junction geometries. At low capillary numbers break-up is not dominated by shear stresses: experimental results support the assertion that the dominant contribution to the dynamics of break-up arises from the pressure drop across the emerging droplet or bubble. This pressure drop results from the high resistance to flow of the continuous (carrier) fluid in the thin films that separate the droplet from the walls of the microchannel when the droplet fills almost the entire cross-section of the channel. A simple scaling relation, based on this assertion, predicts the size of droplets and bubbles produced in the T-junctions over a range of rates of flow of the two immiscible phases, the viscosity of the continuous phase, the interfacial tension, and the geometrical dimensions of the device.

Statistical theory of neutron-nuclear reactions

International Nuclear Information System (INIS)

Moldauer, P.A.

1981-01-01

In addition to the topics dealt with by the author in his lectures at the Joint IAEA/ICTP Course held at Trieste in 1978, recent developments in the statistical theory of multistep reactions are reviewed as well as the transport theory and intranuclear cascade approaches to the description of nuclear multi-step processes. (author)

Study of the break reaction of Be{sup 11} on Ti{sup 48} target; the towing mode: a spectroscopic tool for the study of nuclei; Etude de la reaction de cassure du {sup 11}Be sur cible de {sup 48}Ti; le towing mode, un outil spectroscopique pour l'etude des noyaux

Energy Technology Data Exchange (ETDEWEB)

Lima, V

2004-10-01

In a towing mode reaction the projectile picks up a nucleon from the target and then breaks up by emitting one nucleon. The velocity of the emitted nucleon is boosted by the projectile velocity, leading to the emission of the nucleon in a narrow cone around the direction of the scattered projectile. This work is dedicated to the towing mode in halo nuclei such as Be{sup 11}. The experiment was performed at Ganil facility by bombarding a Ti{sup 48} target with a 41 MeV per nucleon Be{sup 11} beam, the reaction studied is: Ti{sup 48}(Be{sup 11}, Be{sup 10} + n + {gamma}). The first chapter reviews the various nuclear processes that take place when 2 nuclei collide with a particular attention for the towing mode. The second chapter is dedicated to solving the time dependant Schroedinger equation (TDSE) in order to assess the impact of various parameters such as incident energy, target charge or the linking energy of the nucleon, on the towing mode reaction. The third chapter deals with the experimental equipment and set-up including detectors and the data acquisition system. Computerized simulations have been performed in order to assess the efficiency of the detecting system, they are presented in the fourth chapter. A comparison between experimental data and the results from TDSE solving, concerning the energy spectra of the emitted particles, has enabled the author to deduce the spectroscopic factors for the different contributions of the fundamental state of Be{sup 11}, they are presented in the last chapter. The cross-sections of the towing mode are of the magnitude of several tens of milli-barns in the case of weakly bound nuclei like Be{sup 11} which make it an efficient tool to study intern structure of nuclei. (A.C.)

Study of the break reaction of Be{sup 11} on Ti{sup 48} target; the towing mode: a spectroscopic tool for the study of nuclei; Etude de la reaction de cassure du {sup 11}Be sur cible de {sup 48}Ti; le towing mode, un outil spectroscopique pour l'etude des noyaux

Energy Technology Data Exchange (ETDEWEB)

Lima, V

2004-10-01

In a towing mode reaction the projectile picks up a nucleon from the target and then breaks up by emitting one nucleon. The velocity of the emitted nucleon is boosted by the projectile velocity, leading to the emission of the nucleon in a narrow cone around the direction of the scattered projectile. This work is dedicated to the towing mode in halo nuclei such as Be{sup 11}. The experiment was performed at Ganil facility by bombarding a Ti{sup 48} target with a 41 MeV per nucleon Be{sup 11} beam, the reaction studied is: Ti{sup 48}(Be{sup 11}, Be{sup 10} + n + {gamma}). The first chapter reviews the various nuclear processes that take place when 2 nuclei collide with a particular attention for the towing mode. The second chapter is dedicated to solving the time dependant Schroedinger equation (TDSE) in order to assess the impact of various parameters such as incident energy, target charge or the linking energy of the nucleon, on the towing mode reaction. The third chapter deals with the experimental equipment and set-up including detectors and the data acquisition system. Computerized simulations have been performed in order to assess the efficiency of the detecting system, they are presented in the fourth chapter. A comparison between experimental data and the results from TDSE solving, concerning the energy spectra of the emitted particles, has enabled the author to deduce the spectroscopic factors for the different contributions of the fundamental state of Be{sup 11}, they are presented in the last chapter. The cross-sections of the towing mode are of the magnitude of several tens of milli-barns in the case of weakly bound nuclei like Be{sup 11} which make it an efficient tool to study intern structure of nuclei. (A.C.)

Pangea break-up: from passive to active margin in the Colombian Caribbean Realm

Science.gov (United States)

Gómez, Cristhian; Kammer, Andreas

2017-04-01

The break-up of Western Pangea has lead to a back-arc type tectonic setting along the periphery of Gondwana, with the generation of syn-rift basins filled with sedimentary and volcanic sequences during the Middle to Late Triassic. The Indios and Corual formations in the Santa Marta massif of Northern Andes were deposited in this setting. In this contribution we elaborate a stratigraphic model for both the Indios and Corual formations, based on the description and classification of sedimentary facies and their architecture and a provenance analysis. Furthermore, geotectonic environments for volcanic and volcanoclastic rock of both units are postulated. The Indios Formation is a shallow-marine syn-rift basin fill and contains gravity flows deposits. This unit is divided into three segments; the lower and upper segments are related to fan-deltas, while the middle segment is associated to offshore deposits with lobe incursions of submarine fans. Volcanoclastic and volcanic rocks of the Indios and Corual formations are bimodal in composition and are associated to alkaline basalts. Volcanogenic deposits comprise debris, pyroclastic and lava flows of both effusive and explosive eruptions. These units record multiple phases of rifting and reveal together a first stage in the break-up of Pangea during Middle and Late Triassic in North Colombia.

Linking Nuclear Reactions and Nuclear Structure on the Way to the Drip Line

Science.gov (United States)

Dickhoff, Willem

2012-10-01

The present understanding of the role of short- and long-range physics in determining proton properties near the Fermi energy for stable closed-shell nuclei has relied on data from the (e,e'p) reaction. Hadronic tools to extract such spectroscopic information have been hampered by the lack of a consistent reaction description that provides unambiguous and undisputed results. The dispersive optical model (DOM), originally conceived by Claude Mahaux, provides a unified description of both elastic nucleon scattering and structure information related to single-particle properties below the Fermi energy. The DOM provides the starting point to provide a framework in which nuclear reactions and structure data can be analyzed consistently to provide unambiguous spectroscopic information including its asymmetry dependence. Recent extensions of this approach include the treatment of non-locality to describe experimental data like the nuclear charge density based on information of the spectral density below the Fermi energy, the application of the DOM ingredients to the description of transfer reactions, a comparison of the microscopic content of the nucleon self-energy based on Faddeev-RPA calculations emphasizing long-range correlations with DOM potentials, and a study of the relation between a self-energy which includes the effect of short-range correlations with DOM potentials. The most recent Dom implementation currently in progress abandons the constraint of local potentials completely to allow an accurate description of various properties of the nuclear ground state.

The abundant excess heat production during low energy nuclear reaction in the nano scale solid state the cold fusion, 14 years' legacy

International Nuclear Information System (INIS)

Woo, Tae Ho; Miley, George H.; Lipson, Andrei; Kim, Sung O.; Luo, Nie; Castano, Carlos H.

2002-01-01

The quite abundant excess heat and radioactive materials are found during the solid state reaction. This phenomenon has done during the Low Energy Nuclear Reaction (LENR) in the nano scale molecular structure electrodes and Hydrogen compound electrolytes. The Palladium (or Nickel) and Platinum are incorporated as the electrode and the Light Water (H 2 O) as the electrolyte. The excess heat was produced up to 40% in year 2001. The Alpha particles are also detected. The computer code, Coherent Lattice Accelerator Inter-Ionic Reaction Enhancer (CLAIRE) Code System, is constructed for the simulation. The 0.1 A of the distance between two the Hydrogen ion (proton) and Palladium nucleus is the critical point for the nuclear fusion reaction

A sensitivity study of s-process: the impact of uncertainties from nuclear reaction rates

Science.gov (United States)

Vinyoles, N.; Serenelli, A.

2016-01-01

The slow neutron capture process (s-process) is responsible for the production of about half the elements beyond the Fe-peak. The production sites and the conditions under which the different components of s-process occur are relatively well established. A detailed quantitative understanding of s-process nucleosynthesis may yield light in physical processes, e.g. convection and mixing, taking place in the production sites. For this, it is important that the impact of uncertainties in the nuclear physics is well understood. In this work we perform a study of the sensitivity of s-process nucleosynthesis, with particular emphasis in the main component, on the nuclear reaction rates. Our aims are: to quantify the current uncertainties in the production factors of s-process elements originating from nuclear physics and, to identify key nuclear reactions that require more precise experimental determinations. In this work we studied two different production sites in which s-process occurs with very different neutron exposures: 1) a low-mass extremely metal-poor star during the He-core flash (nn reaching up to values of ∼ 1014cm-3); 2) the TP-AGB phase of a M⊙, Z=0.01 model, the typical site of the main s-process component (nn up to 108 — 109cm-3). In the first case, the main variation in the production of s-process elements comes from the neutron poisons and with relative variations around 30%-50%. In the second, the neutron poison are not as important because of the higher metallicity of the star that actually acts as a seed and therefore, the final error of the abundances are much lower around 10%-25%.

A study on the hierarchy model of nuclear reactions

International Nuclear Information System (INIS)

Kitazoe, Yasuhiro; Sekiya, Tamotsu

1975-01-01

The application of the hierarchy model of nuclear reaction is discussed, and the hierarchy model means that the compound nucleus state is formed after several steps, at least, one step of reaction. This model was applied to the analysis of the observed cross sections of 235 U and some other elements. Neglecting exchange scattering effect, the equations for the total neutron cross section of 235 U were obtained. One of these equations describes explicitly the hierarchy of the transition from intermediate reaction state Xm into the compound nucleus state Xs, and another one describes the cross section averaged over an energy interval larger than the average level spacing of compound nucleus eigenvalues. The hierarchy of reaction mechanism was investigated in more detail, and the hierarchy model was applied to the case of unresolved energy region. It was not tried to evaluate the strength function in the mass region (A>140), since the effect of nuclear deformation was neglected in the task. (Iwase, T.)

Nuclear reaction analysis of hydrogen in materials: Principals and applications

International Nuclear Information System (INIS)

Lanford, W.A.

1991-01-01

Analysis for hydrogen in materials is difficult by most traditional analytic methods. Because hydrogen has no Auger transitions, no X-ray transitions, does not neutron activate, and does not backscatter ions, it is invisible in analytical methods based on these effects. In addition, since hydrogen is a universal contaminant in vacuum systems, techniques based on mass spectrometry are difficult unless extreme measures are taken to reduce hydrogen backgrounds. Because of this situation, methods have been developed for analyzing for hydrogen in solid materials based on nuclear reactions between bombarding ions and hydrogen atoms (protons) in the samples. The nuclear reaction methods are now practiced at laboratories around the world. The basic principals of nuclear reaction analysis will be briefly presented. This method will be illustrated by applications to problems ranging from basic physics, to geology, to materials science, and to art history and archeology

Thermonuclear Reaction Rate Libraries and Software Tools for Nuclear Astrophysics Research

International Nuclear Information System (INIS)

Smith, Michael S.; Cyburt, Richard; Schatz, Hendrik; Smith, Karl; Warren, Scott; Ferguson, Ryan; Wiescher, Michael; Lingerfelt, Eric; Buckner, Kim; Nesaraja, Caroline D.

2008-01-01

Thermonuclear reaction rates are a crucial input for simulating a wide variety of astrophysical environments. A new collaboration has been formed to ensure that astrophysical modelers have access to reaction rates based on the most recent experimental and theoretical nuclear physics information. To reach this goal, a new version of the REACLIB library has been created by the Joint Institute for Nuclear Astrophysics (JINA), now available online at http://www.nscl.msu.edu/~nero/db. A complementary effort is the development of software tools in the Computational Infrastructure for Nuclear Astrophysics, online at nucastrodata.org, to streamline, manage, and access the workflow of the reaction evaluations from their initiation to peer review to incorporation into the library. Details of these new projects will be described

Investigation of the reaction 6Li + 40Ca at 156 MeV in a coincidence experiment

International Nuclear Information System (INIS)

Freindl, L.; Grotowski, K.; Uniwersytet Jagiellonski, Krakow; Planeta, R.; Klewe-Nebenius, H.; Neumann, B.; Buschmann, J.; Gils, H.J.; Rebel, H.; Zagromski, S.

1983-12-01

The cross sections for inelastic break up have been studied for the 6 Li + 40 Ca reaction at Esub(Li) = 156 MeV. For this, gamma ray spectra from the heavy residual nuclei were measured in coincidence with beam velocity projectile fragments. The cross sections were found to be: 34 +- 9 14 mb for protons, 30 +- 7 12 mb for deuterons, and 78 +- 41 142 mb for α-particles, respectively. These values are small when compared to total break up cross sections. A comparison of the cross section sum of all known reaction paths induced by 6 Li + 40 Ca at 156 MeV with total reaction cross section indicates a missing cross section of the order of a few hundred millibarns. It is discussed whether this cross section may be attributed to pick up reactions. (orig.) [de

EXFOR Systems Manual Nuclear reaction Data Exchange Format

International Nuclear Information System (INIS)

McLane, V.

2000-01-01

EXFOR is an exchange format designed to allow transmission of nuclear reaction data between the members of the Nuclear Data Centers Network. This document has been written for use by the members of the Network and includes matters of procedure and protocol, as well as detailed rules for the compilation of data. Users may prefer to consult EXFOR Basics' for a brief description of the format

EXFOR SYSTEMS MANUAL NUCLEAR REACTION DATA EXCHANGE FORMAT.

Energy Technology Data Exchange (ETDEWEB)

MCLANE,V.; NUCLEAR DATA CENTER NETWORK

2000-05-19

EXFOR is an exchange format designed to allow transmission of nuclear reaction data between the members of the Nuclear Data Centers Network. This document has been written for use by the members of the Network and includes matters of procedure and protocol, as well as detailed rules for the compilation of data. Users may prefer to consult EXFOR Basics' for a brief description of the format.

Theoretical studies in nuclear reaction and nuclear structure. Progress report, August 1, 1977--July 31, 1978

International Nuclear Information System (INIS)

MacDonald, W.M.; Redish, E.F.

1978-01-01

The research program covers four major areas of nuclear theory: reaction theory including both few-body and many-body systems, intermediate energy reactions including nucleon-nucleon processes, pion physics, and nuclear dynamics. In many-body reaction theory the major achievement has been the development of a unitary and connected Hamiltonian formulation adapted to approximate calculations which include 3-body channels. A new analysis of isobaric analog states attracts high resolution data parameters which characterize these states and provide information about the nucleon-nucleon interaction. The multiple-scattering analysis of approximately GeV proton-nucleus scattering has been validated by agreement in absolute magnitude with new experimental data, and contributions of a nucleon isobar were identified. The Banerjee-Cammarata dynamical theory of the pion-nucleon interaction has been found to satisfy several independent tests of dispersion relations as well as predicting experimental phase shifts. In nuclear dynamics a new S-matrix theory of time-dependent Hartree-Fock promises to provide a new approach to heavy-ion reactions. A list of publications is included

Use of a dam break model to assess flooding at Haddam Neck Nuclear Power Plant

International Nuclear Information System (INIS)

Scherrer, J.S.; Chery, D.L. Jr.

1984-01-01

Because of their proximity to necessary supplies of cooling water, nuclear power plants are susceptible to riverine flooding. Greater flood hazards exist where plants are located downstream of larger dams. The consequences of the Quabbin Reservoir dam failure on the Haddam Neck Nuclear Power Plant situated on the Connecticut River were investigated using a dam break flood routing model. Reasons for selecting a particular model are presented and the input assumption for the modeling process are developed. Relevant information concerning the level of manpower involvement is presented. The findings of this analysis demonstrate that the plant is adequately protected from the consequences of the postulated flood event

Nuclear Data and Reaction Rate Databases in Nuclear Astrophysics

Science.gov (United States)

Lippuner, Jonas

2018-06-01

Astrophysical simulations and models require a large variety of micro-physics data, such as equation of state tables, atomic opacities, properties of nuclei, and nuclear reaction rates. Some of the required data is experimentally accessible, but the extreme conditions present in many astrophysical scenarios cannot be reproduced in the laboratory and thus theoretical models are needed to supplement the empirical data. Collecting data from various sources and making them available as a database in a unified format is a formidable task. I will provide an overview of the data requirements in astrophysics with an emphasis on nuclear astrophysics. I will then discuss some of the existing databases, the science they enable, and their limitations. Finally, I will offer some thoughts on how to design a useful database.

Volcanic passive margins: another way to break up continents.

Science.gov (United States)

Geoffroy, L; Burov, E B; Werner, P

2015-10-07

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

Nuclear reactions with radioactive and stable beams (Part II); Reacciones nucleares con haces radiactivos y estables (Parte II)

Energy Technology Data Exchange (ETDEWEB)

Aguilera R, E.F.; Martinez Q, E.; Gomez C, A.; Lizcano, D. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2005-12-15

At the present time there is a great interest at world level in experiments, with accelerated nuclei of short half life. The dispersion, fusion, transfer and break processes in the interaction of weakly light projectiles bounded with targets of Z great its have been object of intense recent investigation, at world level. Our group, in collaboration with the University of Notre Dame, it has measured and analyzed these processes for weakly bound systems as: {sup 6}He + {sup 209}Bi, {sup 8}Li + {sup 208}Pb, {sup 10}Be + {sup 208}Pb. On the other hand a research line that has wakened up great interest, it is that of studies of resonant reactions using the Inverse Kinematics technique with thick targets. The use of this technique allows to measure an entire excitation function with a single bombardment. Our group has carried out, in the ININ, preliminary bombardments for the system {sup 12}C + {sup 4}He. This allowed to establish the feasibility of implementing this technique in our Laboratory. The application of this and other techniques to different systems like {sup 18}O + {sup 4}He, {sup 12}C + {sup 12}C, {sup 12}C + {sup 16}O, {sup 16}O + {sup 16}O, it opens the possibility to measure the fusion of these systems at very low energy and to deepen in the knowledge of the nuclear structure and the nuclear astrophysics. In this technical report, the activities carried out by our group during the second stage of this project, considered for 2005 are described. Also in that year, our group carries out a research stay in the University of Notre Dame, during this stay, the angular distribution of the projectiles of {sup 8}B dispersed in an enriched target of {sup 58}Ni was measured. The same as in the previous experiments, in this occasion it was also possible to measure those angular distributions of the projectiles of {sup 7}Be and {sup 6}Li dispersed in this same target. In this same one our stay group participates in other three experiments proposed by collaborators of

A Monte Carlo calculation of the pionium break-up probability with different sets of pionium target cross sections

International Nuclear Information System (INIS)

Santamarina, C; Schumann, M; Afanasyev, L G; Heim, T

2003-01-01

Chiral perturbation theory predicts the lifetime of pionium, a hydrogen-like π + π - atom, to better than 3% precision. The goal of the DIRAC experiment at CERN is to obtain and check this value experimentally by measuring the break-up probability of pionium in a target. In order to accurately measure the lifetime one needs to know the relationship between the break-up probability and the lifetime to 1% accuracy. We have obtained this dependence by modelling the evolution of pionic atoms in the target using Monte Carlo methods. The model relies on the computation of the pionium-target-atom interaction cross sections. Three different sets of pionium-target cross sections with varying degrees of complexity were used: from the simplest first-order Born approximation involving only the electrostatic interaction to a more advanced approach, taking into account multiphoton exchanges and relativistic effects. We conclude that, in order to obtain the pionium lifetime to 1% accuracy from the break-up probability, the pionium-target cross sections must be known with the same accuracy for the low excited bound states of the pionic atom. This result has been achieved, for low Z targets, with the two most precise cross section sets. For large Z targets only the set accounting for multiphoton exchange satisfies the condition

'BREAKS' Protocol for Breaking Bad News.

Science.gov (United States)

Narayanan, Vijayakumar; Bista, Bibek; Koshy, Cheriyan

2010-05-01

Information that drastically alters the life world of the patient is termed as bad news. Conveying bad news is a skilled communication, and not at all easy. The amount of truth to be disclosed is subjective. A properly structured and well-orchestrated communication has a positive therapeutic effect. This is a process of negotiation between patient and physician, but physicians often find it difficult due to many reasons. They feel incompetent and are afraid of unleashing a negative reaction from the patient or their relatives. The physician is reminded of his or her own vulnerability to terminal illness, and find themselves powerless over emotional distress. Lack of sufficient training in breaking bad news is a handicap to most physicians and health care workers. Adherence to the principles of client-centered counseling is helpful in attaining this skill. Fundamental insight of the patient is exploited and the bad news is delivered in a structured manner, because the patient is the one who knows what is hurting him most and he is the one who knows how to move forward. Six-step SPIKES protocol is widely used for breaking bad news. In this paper, we put forward another six-step protocol, the BREAKS protocol as a systematic and easy communication strategy for breaking bad news. Development of competence in dealing with difficult situations has positive therapeutic outcome and is a professionally satisfying one.

Projective multifragments break-up and the electromagnetic field effect of target nucleus

International Nuclear Information System (INIS)

Nabil Yasin, M.

1994-12-01

This work presents a special type of interactions produced in emulsion targets exposed to different incident beams of light ions at a few GeV per nucleon. The events characterised by multifragment break-up of the projectile nucleus which are produced via peripheral collisions or due to the effect of the Coulomb field of the target nucleus have been selected. The size of impact parameter must be considered for determining the type of the interaction. The results are compared with other collected data at energies (up to 200 GeV/nucleon). The dependence of electromagnetic dissociation cross section on the incident projectile energy is investigated. Also, a comparison of the experimental data with the assumed virtual photon spectrum using Weizsaecker-Williams (WW) method is made. (author). 34 refs, 3 figs, 4 tabs

Investigations of nuclear structure and nuclear reactions induced by complex projectiles. Technical progress report, November 1, 1978-October 31, 1979

International Nuclear Information System (INIS)

Sarantites, D.G.

1979-01-01

Experimental research on nuclear structure and reactions both published and in progress is summarized. Included are fusion reactions, strongly damped heavy ion collisions, and nuclear structure at high angular momentum. A list of publications is included

Analysis of a gas stratification break-up by a vertical jet using the GOTHIC code

International Nuclear Information System (INIS)

Fernández-Cosials, Mikel Kevin; Jimenez, Gonzalo; Lopez-Alonso, Emma

2016-01-01

Highlights: • Study of a light gas distribution with the GOTHIC code based on the OECD/NEA IBE-3. • Sensitivity analysis on turbulence model, discretization scheme and heat transfer. • The jet erosion phenomena is captured properly with a relatively coarse mesh. • Development of a tool to evaluate the influence of each parameter on the simulation. • Several recommendation on modeling a stratification break-up are included. - Abstract: During a severe accident in light water reactor (LWR), hydrogen concentration can overpass the flammability limits locally, so the correct simulation of its behavior during a release is critical. The capability assessment of computational fluid dynamics tools to calculate the hydrogen distribution under different conditions has been the focus of intense research worldwide. In this context, the OECD/NEA conducted an international benchmark exercise (IBE-3), which was focused on the break-up of a stratified layer of a light gas by a vertical jet. The participants performed their simulations before the experiment data was released. When the data was released, it was noticed that a combination of several parameters like the mesh, turbulence model or solver controls were responsible for the broad differences between the participants’ results. To obtain information about how each parameter affects the simulation, a post-test sensitivity analysis has been done by the UPM. In this paper, the IBE-3 experiment simulation with GOTHIC 8.0 is presented along with extensive sensitivity analyses of the relevant parameters. The first objective of the work is to test the capability of GOTHIC 8.0 to simulate properly a gas stratification break-up by a vertical jet with a relatively coarse mesh. The second objective of the paper is to relate each sensitivity parameter with each other and with the experiment through the Parameter Influence Chart, a helpful tool specially designed for this purpose.

Analysis of a gas stratification break-up by a vertical jet using the GOTHIC code

Energy Technology Data Exchange (ETDEWEB)

Fernández-Cosials, Mikel Kevin; Jimenez, Gonzalo, E-mail: gonzalo.jimenez@upm.es; Lopez-Alonso, Emma

2016-02-15

Highlights: • Study of a light gas distribution with the GOTHIC code based on the OECD/NEA IBE-3. • Sensitivity analysis on turbulence model, discretization scheme and heat transfer. • The jet erosion phenomena is captured properly with a relatively coarse mesh. • Development of a tool to evaluate the influence of each parameter on the simulation. • Several recommendation on modeling a stratification break-up are included. - Abstract: During a severe accident in light water reactor (LWR), hydrogen concentration can overpass the flammability limits locally, so the correct simulation of its behavior during a release is critical. The capability assessment of computational fluid dynamics tools to calculate the hydrogen distribution under different conditions has been the focus of intense research worldwide. In this context, the OECD/NEA conducted an international benchmark exercise (IBE-3), which was focused on the break-up of a stratified layer of a light gas by a vertical jet. The participants performed their simulations before the experiment data was released. When the data was released, it was noticed that a combination of several parameters like the mesh, turbulence model or solver controls were responsible for the broad differences between the participants’ results. To obtain information about how each parameter affects the simulation, a post-test sensitivity analysis has been done by the UPM. In this paper, the IBE-3 experiment simulation with GOTHIC 8.0 is presented along with extensive sensitivity analyses of the relevant parameters. The first objective of the work is to test the capability of GOTHIC 8.0 to simulate properly a gas stratification break-up by a vertical jet with a relatively coarse mesh. The second objective of the paper is to relate each sensitivity parameter with each other and with the experiment through the Parameter Influence Chart, a helpful tool specially designed for this purpose.

Nuclear reactions induced by high-energy alpha particles

Science.gov (United States)

Shen, B. S. P.

1974-01-01

Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

Improved Simulation of the Pre-equilibrium Triton Emission in Nuclear Reactions Induced by Nucleons

Science.gov (United States)

Konobeyev, A. Yu.; Fischer, U.; Pereslavtsev, P. E.; Blann, M.

2014-04-01

A new approach is proposed for the calculation of non-equilibrium triton energy distributions in nuclear reactions induced by nucleons of intermediate energies. It combines models describing the nucleon pick-up, the coalescence and the triton knock-out processes. Emission and absorption rates for excited particles are represented by the pre-equilibrium hybrid model. The model of Sato, Iwamoto, Harada is used to describe the nucleon pick-up and the coalescence of nucleons from exciton configurations starting from (2p,1h) states. The contribution of the direct nucleon pick-up is described phenomenologically. Multiple pre-equilibrium emission of tritons is accounted for. The calculated triton energy distributions are compared with available experimental data.

Break-up of Ca-montmorillonite particles by Na-montmorillonite

International Nuclear Information System (INIS)

Hedstroem, Magnus; Birgersson, Martin

2012-01-01

Document available in extended abstract form only. In the Swedish KBS-3 concept for a geological deep storage of spent nuclear fuel, bentonite of high montmorillonite content is proposed to serve as a buffer surrounding copper canisters containing the spent fuel. Montmorillonite has an exceptional affinity for water which results in the build-up of a swelling pressure when bentonite is placed in a confined volume. However, there is a concern that during and after a glaciation, meltwater of low ionic strength may cause the bentonite to swell extensively into fractures and turn into a sol that could be transported away by the seeping water. It is thus warranted to understand the behaviour of montmorillonite at aqueous condition of low ionic strength. Turbidity measurements were used to a large extent in previous work to follow the free swelling or settling process of montmorillonite in various aqueous solutions and thereby give information regarding sol formation. From theory we know that turbidity of a suspension is proportional to the particle concentration. However turbidity is also proportional to V p 2 where V p is the volume of the scattering particle. Thus the fact that turbidity of a Ca-montmorillonite suspension is higher than the turbidity of a Na- montmorillonite suspension of the same clay concentration indicates that Na-montmorillonite separate into smaller particles than Ca-montmorillonite. In this work we make use this size dependence to quantify the difference between Wyoming, Milos and Kutch montmorillonite in particular with respect to how mixed Ca/Na montmorillonite systems behave. Some Ca/Mg, Mg/Na and Na/K systems are also included for comparison. Figure 1 shows the final (stabilized) turbidity response of mixed Wy-Ca/Na montmorillonite as a function of the fraction of Ca 2+ in the clay. Starting material are suspensions of homo-ionic Wy-Ca and Wy-Na montmorillonite at a concentration of 1 g/l. The turbidity of the suspensions of the homo

The abundant excess heat production during low energy nuclear reaction in the nano scale solid state the cold fusion, 14 years' legacy

Energy Technology Data Exchange (ETDEWEB)

Woo, Tae Ho; Miley, George H.; Lipson, Andrei; Kim, Sung O.; Luo, Nie; Castano, Carlos H. [The University of Illinois, Urbana (United States)

2002-05-01

The quite abundant excess heat and radioactive materials are found during the solid state reaction. This phenomenon has done during the Low Energy Nuclear Reaction (LENR) in the nano scale molecular structure electrodes and Hydrogen compound electrolytes. The Palladium (or Nickel) and Platinum are incorporated as the electrode and the Light Water (H{sub 2}O) as the electrolyte. The excess heat was produced up to 40% in year 2001. The Alpha particles are also detected. The computer code, Coherent Lattice Accelerator Inter-Ionic Reaction Enhancer (CLAIRE) Code System, is constructed for the simulation. The 0.1 A of the distance between two the Hydrogen ion (proton) and Palladium nucleus is the critical point for the nuclear fusion reaction.

Statistical methods of spin assignment in compound nuclear reactions

International Nuclear Information System (INIS)

Mach, H.; Johns, M.W.

1984-01-01

Spin assignment to nuclear levels can be obtained from standard in-beam gamma-ray spectroscopy techniques and in the case of compound nuclear reactions can be complemented by statistical methods. These are based on a correlation pattern between level spin and gamma-ray intensities feeding low-lying levels. Three types of intensity and level spin correlations are found suitable for spin assignment: shapes of the excitation functions, ratio of intensity at two beam energies or populated in two different reactions, and feeding distributions. Various empirical attempts are examined and the range of applicability of these methods as well as the limitations associated with them are given. 12 references

Statistical methods of spin assignment in compound nuclear reactions

International Nuclear Information System (INIS)

Mach, H.; Johns, M.W.

1985-01-01

Spin assignment to nuclear levels can be obtained from standard in-beam gamma-ray spectroscopy techniques and in the case of compound nuclear reactions can be complemented by statistical methods. These are based on a correlation pattern between level spin and gamma-ray intensities feeding low-lying levels. Three types of intensity and level spin correlations are found suitable for spin assignment: shapes of the excitation functions, ratio of intensity at two beam energies or populated in two different reactions, and feeding distributions. Various empirical attempts are examined and the range of applicability of these methods as well as the limitations associated with them are given

The experimental nuclear reaction data (EXFOR): Extended computer database and Web retrieval system

Science.gov (United States)

Zerkin, V. V.; Pritychenko, B.

2018-04-01

The EXchange FORmat (EXFOR) experimental nuclear reaction database and the associated Web interface provide access to the wealth of low- and intermediate-energy nuclear reaction physics data. This resource is based on numerical data sets and bibliographical information of ∼22,000 experiments since the beginning of nuclear science. The principles of the computer database organization, its extended contents and Web applications development are described. New capabilities for the data sets uploads, renormalization, covariance matrix, and inverse reaction calculations are presented. The EXFOR database, updated monthly, provides an essential support for nuclear data evaluation, application development, and research activities. It is publicly available at the websites of the International Atomic Energy Agency Nuclear Data Section, http://www-nds.iaea.org/exfor, the U.S. National Nuclear Data Center, http://www.nndc.bnl.gov/exfor, and the mirror sites in China, India and Russian Federation.

Search for R-Parity Breaking Sneutrino Exchange at LEP

CERN Document Server

Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Button, A M; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chéreau, X J; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Della Volpe, D; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hong, S J; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Milcent, H; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sassowsky, M; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, A; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

1997-01-01

We report on a search for R--parity breaking effects due to supersymmetric tau--sneutrino exchange in the reactions e+e- to e+e- and e+e- to mu+mu- at centre--of--mass energies from 91~{\\GeV} to 172~{\\GeV}, using the L3 detector at LEP. No evidence for deviations from the Standard Model expectations of the measured cross sections and forward--backward asymmetries for these reactions is found. Upper limits for the couplings $\\lambda_{131}$ and $\\lambda_{232}$ for sneutrino masses up to $m_{\\SNT} \\leq 190~\\GeV$ are determined from an analysis of the expected effects due to tau sneutrino exchange.

Movement of a female polar bear (Ursus maritimus) in the Kara Sea during the summer sea-ice break-up.

Science.gov (United States)

Rozhnov, V V; Platonov, N G; Naidenko, S V; Mordvintsev, I N; Ivanov, E A

2017-01-01

The polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the Taimyr Peninsula, eastern part of the Kara Sea, using as an example a female polar bear tagged by a radio collar with an Argos satellite transmitter. Analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that direction of the polar bear movement depends precisely on the direction of the sea-ice cover break-up.

The effect of enterprise break-ups on performance: the case of the former Yugoslav Republic of Macedonia

Czech Academy of Sciences Publication Activity Database

Domadenik, P.; Lízal, Lubomír; Pahor, M.

2012-01-01

Roč. 63, č. 5 (2012), s. 849-866 ISSN 0035-2764 Institutional support: RVO:67985998 Keywords : enterprise break-ups * Macedonia * performance Subject RIV: AH - Economics http://www.cairn.info/resume.php?ID_ARTICLE=RECO_635_0849

Nuclear reaction analysis (NRA) for trace element detection

Energy Technology Data Exchange (ETDEWEB)

Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Noll, K. [Bern Univ. (Switzerland)

1997-09-01

Ion beam induced nuclear reactions can be used to analyse trace element concentrations in materials. The method is especially suited for the detection of light contaminants in heavy matrices. (author) 3 figs., 2 refs.

Nuclear dynamics in heavy ion induced fusion-fission reactions

International Nuclear Information System (INIS)

Kapoor, S.S.

1992-01-01

Heavy ion induced fission and fission-like reactions evolve through a complex nuclear dynamics encountered in the medium energy nucleus-nucleus collisions. In the recent years, measurements of the fragment-neutron and fragment-charged particle angular correlations in heavy ion induced fusion-fission reactions, have provided new information on the dynamical times of nuclear deformations of the initial dinuclear complex to the fission saddle point and the scission point. From the studies of fragment angular distributions in heavy ion induced fission it has been possible to infer the relaxation times of the dinuclear complex in the K-degree of freedom and our recent measurements on the entrance channel dependence of fragment anisotropies have provided an experimental signature of the presence of fissions before K-equilibration. This paper reviews recent experimental and theoretical status of the above studies with particular regard to the questions relating to dynamical times, nuclear dissipation and the effect of nuclear dissipation on the K-distributions at the fission saddle in completely equilibrated compound nucleus. (author). 19 refs., 9 figs

Electrodeless, multi-megawatt reactor for room-temperature, lithium-6/deuterium nuclear reactions

International Nuclear Information System (INIS)

Drexler, J.

1993-01-01

This paper describes a reactor design to facilitate a room-temperature nuclear fusion/fission reaction to generate heat without generating unwanted neutrons, gamma rays, tritium, or other radioactive products. The room-temperature fusion/fission reaction involves the sequential triggering of billions of single-molecule, 6 LiD 'fusion energy pellets' distributed in lattices of a palladium ion accumulator that also acts as a catalyst to produce the molecules of 6 LiD from a solution comprising D 2 O, 6 LiOD with D 2 gas bubbling through it. The D 2 gas is the source of the negative deuterium ions in the 6 LiD molecules. The next step is to trigger a first nuclear fusion/fission reaction of some of the 6 LiD molecules, according to the well-known nuclear reaction: 6 Li + D → 2 4 He + 22.4 MeV. The highly energetic alpha particles ( 4 He nuclei) generated by this nuclear reaction within the palladium will cause shock and vibrations in the palladium lattices, leading to compression of other 6 LiD molecules and thereby triggering a second series of similar fusion/fission reactions, leading to a third series, and so on. The absorption of the kinetic energy in the palladium will, in turn, generate a continuous flow of heat into the heavy water carrier, which would be removed with a heat exchanger. (author)

Non extensive corrections to stellar nuclear reactions rate

Energy Technology Data Exchange (ETDEWEB)

Assuncao, M. [Universidade Federal de Sao Paulo (DCET/UNIFESP), Diadema, SP (Brazil). Dept. de Ciencias Exatas e da Terra; Silveira, F.E.M. [Universidade Federal do ABC, Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas; Lima, J.A.S. [Universidade de Sao Paulo (IAG/USP), SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas

2010-07-01

Full text: Stellar nucleosynthesis is widely accepted as the basic mechanism for creation of chemical elements in the Universe. In particular, nuclear reactions occurring in the Sun are recognized as responsible for its energy generation. The problem of to determine the energy generation mechanism in stars was firstly attacked by Gamow in the framework of his quantum mechanical theory of potential barrier penetration. According to that approach, the reactions rate is calculated by averaging the penetration factor over the velocity distribution of the plasma particles. A randomization of that distribution is expected as a consequence of the reactions. However, diffusion processes in the macroscopic environment should balance the resulting particles number depletion. Therefore, matter, energy, and momentum might steadily flow. In other words, a quasi-stationary equilibrium state must be attained. In this work, the potential barrier penetration approach to stellar nuclear reactions rate has been rediscussed with basis on Tsallis nonextensive statistics. The investigation has been restricted to non-resonant reactions, for which the S-factor can be regarded as a constant. It has been found that, within the extended formulation, the nonextensive q-parameter is constrained to a maximum value. Accordingly, the q-energy has been shown to exhibit a minimum. The q-Gamow peak has been derived and, in connection with the usual Gaussian approximation, the corresponding half q-width has been also estimated. Plots of the q-energy, q-Gamow peak and half q-width for some reactions with stellar physics interest have been produced. (author)

Big break for charge symmetry

Energy Technology Data Exchange (ETDEWEB)

Miller, G.A. [Department of Physics, University of Washington, Seattle (United States); Kolck, U. van [Department of Physics, University of Arizona, Tucson (United States)

2003-06-01

production of neutral pi-mesons (pions) when a neutron is captured by a proton in a hydrogen target to form a deuteron. The probability, or cross-section, for this n + p {yields} d + {pi}{sup 0} reaction to occur depends on the angle between the momentum of the outgoing pion and that of the incident neutron beam. Another experimental team, led by Andy Bacher and Ed Stephenson at Indiana University in the US. Since the 1950s experimentalists have been trying to detect the formation of a neutral pion and an alpha particle in the fusion of two deuterons, d + d {yields} {alpha} +{pi}{sup 0}. The experiment was approved and everything was set and ready, except for the fact that the IUCF was already scheduled to be transformed into a materials and medical research facility. Bacher and Stephenson's team worked frantically for two months and finally produced two separate observations of a beautiful peak at exactly the right pion energy. Their experimental cross-section is almost the same as our estimate, and this measurement of such a small charge-symmetry-breaking probability is an immense technical achievement. Now the ball is back in the theorists' court. A large group, including Antonio Fonseca at the University of Lisbon in Portugal, Anders Gardestig and Chuck Horowitz at Indiana University, Andreas Nogga at the University of Arizona, and the present authors, is carrying out the task of turning the initial estimate of the cross-section of the d + d {yields} {alpha} +{pi}{sup 0} reaction into a reliable calculation. The same charge-symmetry-breaking mechanisms contribute to both the TRIUMF and IUCF experiments, which means that together they can provide important information on the mass difference between up and down quarks. The origin of the quark masses is not fully understood. In the Standard Model of particle physics, the Higgs mechanism allows the generation of such masses but it cannot predict the actual mass values. This is like having a recipe to make cookies

Low-energy nuclear reactions with double-solenoid- based ...

Indian Academy of Sciences (India)

solenoids to produce low-energy radioactive nuclear beams. In these systems the ... For many years, the disadvantage in these investigations ... fusion or breakup reaction, preferred with large forward-peaked cross-sections. To transfer the ...

Photoneutron Reaction Data for Nuclear Physics and Astrophysics

Science.gov (United States)

Utsunomiya, Hiroaki; Renstrøm, Therese; Tveten, Gry Merete; Gheorghe, Ioana; Filipescu, Dan Mihai; Belyshev, Sergey; Stopani, Konstantin; Wang, Hongwei; Fan, Gongtao; Lui, Yiu-Wing; Symochko, Dmytro; Goriely, Stephane; Larsen, Ann-Cecilie; Siem, Sunniva; Varlamov, Vladimir; Ishkhanov, Boris; Glodariu, Tudor; Krzysiek, Mateusz; Takenaka, Daiki; Ari-izumi, Takashi; Amano, Sho; Miyamoto, Shuji

2018-05-01

We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032).

Role amplification of the coulomb interaction in nuclear reactions

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ashok; Soni, S K; Pancholi, S K; Gupta, S L [AN SSSR, Moscow. Radiotekhnicheskij Inst.

1976-10-01

The genarally adopted estimate of coulomb interaction in nuclear reactions based on the comparison of relative energies of real particles participating in the reaction with the coulomb barrier has been shown to provide wrong presentation of the role of coulomb interaction in the reaction mechanism. The relative energy of particles participating in virtual processes forming the reaction mechanism and its relation to the coulomb barrier turn out to be tens of per cent less than for the particles in an inlet channel. This is the main reason of increasing the role of coulomb interaction in the reaction mechanism. This increase is particularly significant for nuclei with large charges, in particular, in heavy ion reaction.

Development of nuclear reaction data retrieval system on Meme media

International Nuclear Information System (INIS)

Ohbayasi, Yosihide; Masui, Hiroshi; Aoyama, Shigeyoshi; Kato, Kiyoshi; Chiba, Masaki

2000-01-01

A newly designed retrieval system of charged particle nuclear reaction data is developed on Meme media architecture. We designed the network-based (client-server) retrieval system. The server system is constructed on a UNIX workstation with a relational database, and the client system is constructed on Microsoft Windows PC using an IntelligentPad software package. The IntelligentPad is currently available as developing Meme media. We will develop the system to realize effective utilization of nuclear reaction data: I. 'Re-production, Re-edit, Re-use', II. 'Circulation, Coordination and Evolution', III. 'Knowledge discovery'. (author)

A workshop report on nuclear reaction and cluster structure

International Nuclear Information System (INIS)

1985-01-01

A work shop was held in June 1984 at RCNP (Research Center for Nuclear Physics), Osaka University, to discuss theory of nuclear reactions based on studies from microscopic or cluster structure viewpoints. About forty researchers participated in this work shop and 27 paperes were presented. All these papers with English abstracts are gathered in this collective report. (Aoki, K.)

From nuclear reactions to liquid-drop collisions

International Nuclear Information System (INIS)

Menchaca R, A.; Huidobro, F.; Martinez D, A.; Michaelian, K.; Perez, A.; Rodriguez, V.; Carjan, N.

1997-01-01

A review of the experimental and theoretical situation in coalescence and fragmentation studies of binary liquid-drop collisions is given, putting in perspective our own contributions, which include experiments with mercury and oil drops and the application of a nuclear reaction model, specifically modified by us for the macroscopic case. (Author)

Magmatism during Gondwana break-up : new geochronological data from Westland, New Zealand

International Nuclear Information System (INIS)

Van der Meer, Q.H.A.; Scott, J.M.; Waight, T.E.; Sudo, M.; Schersten, A.; Cooper, A.F.; Spell, T.L.

2013-01-01

Newly determined Late Cretaceous 40 Ar/ 39 Ar ages on megacrystic kaersutite from four lamprophyre dikes, and a U-Pb zircon age on a trachyte, from central and north Westland (New Zealand) are presented. These ages suggest that the intrusion of mafic dikes (88-86 and 69 Ma) was not necessarily restricted to the previously established narrow age range of 80-92 Ma. The younger lamprophyre and trachyte dikes (c. 68-70 Ma) imply that tensional stresses in the Western Province were either renewed at this time, or that extension and related magmatism continued during opening of the Tasman Sea. Extension-related magmatism in the region not only preceded Tasman seafloor spreading initiation (starting at c. 83 Ma, lasting to c. 53 Ma), but may have sporadically continued for up to 15 Ma after continental break-up. (author)

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

1998-01-01

(full text) During the last year our activities were spread over the three major domains: nuclear, atomic and material physics. The nuclear physics experimental programme covered a broad range of nuclear reactions induced by light and heavy ions. New experiments were performed at the compact C-30 cyclotron at Swierk, at University of Jyvaeskylae, GSI Darmstadt, LN Saturne. Prospects for future experiments on nucleon structure at Forschungszentrum Juelich were open. The collaboration with INR Kiev was tightened and work was done in order to prepare experiments at the C-200 heavy ion cyclotron in Warsaw. An effort to install the ion guide isotope separator on line (IGISOL) at the C-200 cyclotron has also to be mentioned A half a year stay of Dr. Nicholas Keeley in the Department, who received The Royal Society/Polish Academy of Science grant, resulted in many interesting results on breakup of light nuclei. Details can be found in the short abstracts presented in this report. As far as atomic physics is concerned, the activity of a group lead by Prof. Marian Jaskola yielded various new results. The experiments were performed at the University of Erlangen, in close collaboration with the Pedagogical University in Kielce and the University of Basel. Fast neutrons generated in the 3 H(d,n) 4 He reaction induced by the 2 MeV deuteron beam from the Van der Graaff accelerator at the Department were used to calibrate solid state-nuclear-track detectors. This was a very good year for material physics research: Jan Kaczanowski and Slawomir Kwiatkawski received Ph.D. degrees based on dissertation research performed in the material physics research programme, while Pawel Kolodziej completed his MSc. thesis in collaboration with the Institute of Electronic Materials Technology in Warsaw, Research Center Karlsruhe, University of Jena and CSNSM Orsay many results were obtained. Lech Nowicki and Prof. Andrzej Turos were awarded by the Director of the IPJ prizes for their scientific

Photopion reactions, a probe for nuclear critical opalescence

International Nuclear Information System (INIS)

Delorme, J.

1980-07-01

It is shown that photopion reactions are a good probe of the nuclear pion field for momenta characteristic of pion condensation. They are thus a direct detector of critical opalescence. Best conditions for experimental detection are discussed

Coolant clean-up system in nuclear reactor

International Nuclear Information System (INIS)

Tsuburaya, Hirobumi; Akita, Minoru; Shiraishi, Tadashi; Kinoshita, Shoichiro; Okura, Minoru; Tsuji, Akio.

1987-01-01

Purpose: To ensure a sufficient urging pressure at the inlet of a coolant clean-up system pump in a nuclear reactor and eliminate radioactive contaminations to the pump. Constitution: Coolant clean-up system (CUW) pump in a nuclear reactor is disposed to the downstream of a filtration desalter and, for compensating the insufficiency of the urging pressure at the pump inlet, the reactor water intake port to the clean-up system is disposed to the downstream of the after-heat removing pump and the heat exchanger. By compensating the net positive suction head (NPSH) of the clean-up system from the residual heat removing system, the problems of insufficient NPSH for the CUW pump upon reactor shut-down can be dissolved and, accordingly, the reactor clean-up system can be arranged in the order of the heat exchanger, clean-up device and pump. Thus, the CUW pump acts on reactor water after cleaned-up in the clean-up device to reduce the radioactivity contamination to the pump. (Kawakami, Y.)

Different aspects of nuclear physics from low energies up to intermediate energies

International Nuclear Information System (INIS)

Lallouet, Y.

2011-12-01

This study focuses on different aspects of nuclear physics from low energies to intermediate ones. For the low energies, the nuclear matter is essentially constituted from interacting nucleons. Part I is on the fusion-fission of super-heavy elements, while Part II is on the Skyrme interactions associated sum rules. In the case of the intermediate energies, where the nuclear matter is considered as being an hadronic phase mainly constituted from pions, Part III is focused on nuclear matter relativistic hydrodynamics with spontaneous chiral symmetry breaking. In Part I, the formation and the deexcitation of super-heavy nuclei are being studied. The memory effect must be taken into consideration within the super-heavy nuclei formation dynamics. Therefore we analyzed the formation of compound nuclei including the memory effects. As for the intermediate memory effects some oscillations appear, which is very different from the Markovian dynamics. For super-heavy nuclei deexcitation, the existence of isomeric state within the potential barrier cannot explain the results of experiments performed at GANIL with the crystal blocking technique, and this despite of the fact that it modifies the deexcitation dynamics and increases the fission time. However, this latter study could be useful for the study of the actinides fission. In Part II, the phenomenological Skyrme effective interactions-associated M 1 and M 3 sum rules are being calculated based on their intrinsic definitions. We identify then M 1 up to the tensorial level and M 3 with central potential. In Part III, as for the hadronic matter hydrodynamics being applied to heavy ions collisions, and as a first approach only, we can neglect spontaneous chiral symmetry but certainly not the dissipative impact. (author)

Novel Role of Superfluidity in Low-Energy Nuclear Reactions.

Science.gov (United States)

Magierski, Piotr; Sekizawa, Kazuyuki; Wlazłowski, Gabriel

2017-07-28

We demonstrate, within symmetry unrestricted time-dependent density functional theory, the existence of new effects in low-energy nuclear reactions which originate from superfluidity. The dynamics of the pairing field induces solitonic excitations in the colliding nuclear systems, leading to qualitative changes in the reaction dynamics. The solitonic excitation prevents collective energy dissipation and effectively suppresses the fusion cross section. We demonstrate how the variations of the total kinetic energy of the fragments can be traced back to the energy stored in the superfluid junction of colliding nuclei. Both contact time and scattering angle in noncentral collisions are significantly affected. The modification of the fusion cross section and possibilities for its experimental detection are discussed.

Photoneutron Reaction Data for Nuclear Physics and Astrophysics

Directory of Open Access Journals (Sweden)

Utsunomiya Hiroaki

2018-01-01

Full Text Available We discuss the role of photoneutron reaction data in nuclear physics and astrophysics in conjunction with the Coordinated Research Project of the International Atomic Energy Agency with the code F41032 (IAEA-CRP F41032.

Complementarity between neutron capture and heavy-ion reactions in nuclear structure studies

International Nuclear Information System (INIS)

Schult, O.W.B.

1978-01-01

The study of the complementarity of certain nuclear reactions in nuclear structure studies includes spectroscopic methods, nuclear rotation and coupling of nucleons to the core, and the de-excitation and structure of high lying states. 23 references

Direct interaction in nuclear reactions: a theory

International Nuclear Information System (INIS)

Dominicis, C.T. de

1959-01-01

General treatment of the foundations of direct interaction in nuclear reactions; representation of the instantaneous elastic scattering amplitude by the scattering amplitude due to a complex potential; expansion of the instantaneous inelastic scattering amplitude and discussion of the 1. Bohr approximation (distorted waves) contribution to individual and collective states of excitation. (author) [fr

Theory of nuclear structure and reactions. Annual technical progress report, April 1, 1984-March 31, 1985

International Nuclear Information System (INIS)

Macfarlane, M.H.; Serot, B.D.

1985-01-01

In the period covered by this report, work focused on five main areas: (1) relativistic effects in intermediate-energy nuclear reactions; (2) the role of quarks and gluons in nuclear physics; (3) quantum hadrodynamics and relativistic nuclear mean-field theory; (4) structure and reaction effects in intermediate-energy nuclear reactions; and (5) weak and electromagnetic interactions in nuclei. Results and publications in these areas are summarized. Publications are listed

Laser induced nuclear reactions

International Nuclear Information System (INIS)

Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin

1998-01-01

Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10 19 W/cm 2 . In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that μCi of 62 Cu can be generated via the (γ,n) reaction by a laser with an intensity of about 10 19 Wcm -2

Nuclear fuel burn-up economy; Ekonomija izgaranja nuklearnog goriva

Energy Technology Data Exchange (ETDEWEB)

Matausek, M [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1984-07-01

In the period 1981-1985, for the needs of Utility Organization, Beograd, and with the support of the Scientific Council of SR Srbija, work has been performed on the study entitled 'Nuclear Fuel Burn-up Economy'. The forst [phase, completed during the year 1983 comprised: comparative analysis of commercial NPP from the standpoint of nuclear fuel requirements; development of methods for fuel burn-up analysis; specification of elements concerning the nuclear fuel for the tender documentation. The present paper gives the short description of the purpose, content and results achieved in the up-to-now work on the study. (author)

Bracing up for a global nuclear renaissance

International Nuclear Information System (INIS)

Autebert, Remy

2008-01-01

The nuclear new build market is dynamic: the nuclear renaissance is here. The challenge facing today the nuclear industry is to meet this strong demand: design and build new reactors..... and ensure an adequate fuel supply for the existing reactors and the new ones. AREVA is getting ready to meet those needs. To answer in the best possible way the call of several new customers, and to make the necessary investments AREVA has made the choice of complementing its own strength with new alliances. When it was created, AREVA has set a new model: an integrated group capable of supplying all parts of the nuclear cycle, from Uranium mining to reactor design construction and servicing, and then up to used fuel management and recycling. This merger of reactor activities and fuel cycle services has proved successful. Focused acquisitions have further strengthened our own capabilities. In addition, AREVA has set-up several alliances to further develop the nuclear market. In the United States, AREVA joined forces with the US utility Constellation to create Uni Star to promoting the EPR. Today, several US utilities are choosing the AREVA's US-EPR. They will benefit from the experience gained in licensing and building the EPR in Finland, in France and soon in China. And they will benefit of course from the unique features of the EPR: easier maintenance, shorter outage, enhanced safety. Willing to meet the growing demand of countries launching a new nuclear program, AREVA set up an alliance with MHI to design a mid-size reactor, ATEMEA 1. Such an alliance allows to speed-up time to market of this new product, which will offer the latest available technologies. In the fuel cycle, AREVA has also developed acquisitions and alliances. As an example, thanks to such an alliance, the new enrichment plant GB-2, could get access to the most efficient centrifugation process. In this fast growing global market, at AREVA we believe into the value of collaboration and partnership to best serve

Summary Report of the Workshop on the Experimental Nuclear Reaction Data Database

International Nuclear Information System (INIS)

Semkova, V.; Pritychenko, B.

2014-12-01

The Workshop on the Experimental Nuclear Reaction Data Database (EXFOR) was held at IAEA Headquarters in Vienna from 6 to 10 October 2014. The workshop was organized to discuss various aspects of the EXFOR compilation process including compilation rules, different techniques for nuclear reaction data measurements, software developments, etc. A summary of the presentations and discussions that took place during the workshop is reported here. (author)

Summary Report of the Workshop on The Experimental Nuclear Reaction Data Database

Energy Technology Data Exchange (ETDEWEB)

Semkova, V. [IAEA Nuclear Data Section, Vienna (Austria); Pritychenko, B. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2014-12-01

The Workshop on the Experimental Nuclear Reaction Data Database (EXFOR) was held at IAEA Headquarters in Vienna from 6 to 10 October 2014. The workshop was organized to discuss various aspects of the EXFOR compilation process including compilation rules, different techniques for nuclear reaction data measurements, software developments, etc. A summary of the presentations and discussions that took place during the workshop is reported here.

Direct reactions in inverse kinematics for nuclear structure studies far off stability at low incident energies

International Nuclear Information System (INIS)

Egelhof, P.

1997-02-01

The investigation of light-ion induced direct reactions with exotic beams in inverse kinematics gives access to a wide field of nuclear structure studies in the region far off stability. The present contribution will focus on the investigation of few-nucleon transfer reactions, which turn out to be most favourably studied with good-quality low-energy radioactive beams, as provided by the new generation of radioactive beam facilities presently planned or under construction at Caen, Grenoble, Munich, and elsewhere. An overview on the physics motivation, basically concerning nuclear structure and nuclear astrophysics questions, is given. Of particular interest are the nuclear shell model in the region far off stability, the two-body residual interaction in nuclei, the structure of halo nuclei, as well as the understanding of the r-process scenario. The experimental conditions, along with the experimental concept, for such measurements are discussed with particular emphasis on the kinematical conditions, the observables, as well as the appropriate detection schemes. The concept of a large solid angle TPC ionization chamber as an active target for experiments with low-energy radioactive beams is presented. It turns out to be a highly effective detection scheme, well suited for the present experimental conditions, at least for light exotic beams up to Z∼20. (orig.)

OECD-LOFT large break LOCA experiments: phenomenology and computer code analyses

International Nuclear Information System (INIS)

Brittain, I.; Aksan, S.N.

1990-08-01

Large break LOCA data from LOFT are a very important part of the world database. This paper describes the two double-ended cold leg break tests LP-02-6 and LP-LB-1 carried out within the OECD-LOFT Programme. Tests in LOFT were the first to show the importance of both bottom-up and top-down quenching during blowdown in removing stored energy from the fuel. These phenomena are discussed in detail, together with the related topics of the thermal performance of nuclear fuel and its simulation by electric fuel rod simulators, and the accuracy of cladding external thermocouples. The LOFT data are particularly important in the validation of integral thermal-hydraulics codes such as TRAC and RELAP5. Several OECD partner countries contributed analyses of the large break tests. Results of these analyses are summarised and some conclusions drawn. 32 figs., 3 tabs., 45 refs

NEA contributions to the worldwide collection, compilation and dissemination of nuclear reaction data

International Nuclear Information System (INIS)

Dupont, E.

2012-01-01

The NEA Data Bank is an international centre of reference for basic nuclear tools used in the analysis and prediction of phenomena in different nuclear applications. The Data Bank collects and compiles computer codes and scientific data and contributes to their improvement for the benefit of scientists in its member countries. In line with this mission, the Data Bank is a core centre of the International Network of Nuclear Reaction Data Centres (NRDC), which co-ordinates the worldwide collection, compilation and dissemination of nuclear reaction data. The NRDC network was established in 1976 from the earlier Four-Centres' Network created in 1966 by the United States, the NEA, the International Atomic Energy Agency (IAEA) and the former Soviet Union. Today, the NRDC is a worldwide co-operation network under the auspices of the IAEA, with 14 nuclear data centres from 8 countries and 2 international organisations belonging to the network. The main objective of the NRDC is to preserve, update and disseminate experimental nuclear reaction data that have been compiled for more than 40 years in a shared database (EXFOR). The EXFOR database contains basic nuclear data on low- to medium-energy experiments for incident neutron, photon and various charged-particle-induced reactions on a wide range of isotopes, natural elements and compounds. Today, with more than 140 000 data sets from approximately 20 000 experiments, EXFOR is by far the most important and complete experimental nuclear reaction database in the world and is widely used in the field of nuclear science and technology. The Data Bank is responsible for the collection and compilation of nuclear reaction data measured in its geographical area. Since 1966, the Data Bank has contributed around 5 000 experiments to the EXFOR database, and it continues to compile new data while maintaining the highest level of quality throughout the database. NRDC co-ordination meetings are held on a biennial basis. Recent meetings

Deterministic 3D transport, sensitivity and uncertainty analysis of TPR and reaction rate measurements in HCPB Breeder Blanket mock-up benchmark

International Nuclear Information System (INIS)

Kodeli, I.

2006-01-01

The Helium-Cooled Pebble Bed (HCPB) Breeder Blanket mock-up benchmark experiment was analysed using the deterministic transport, sensitivity and uncertainty code system in order to determine the Tritium Production Rate (TPR) in the ceramic breeder and the neutron reaction rates in beryllium, both nominal values and the corresponding uncertainties. The experiment, performed in 2005 to validate the HCPB concept, consists of a metallic beryllium set-up with two double layers of breeder material (Li 2 CO 3 powder). The reaction rate measurements include the Li 2 CO 3 pellets for the tritium breeding monitoring and activation foils, inserted at several axial and lateral locations in the block. In addition to the well established and validated procedure based on the 2-dimensional (2D) code DORT, a new approach for the 3D modelling was validated based on the TORT/GRTUNCL3D transport codes. The SUSD3D code, also in 3D geometry, was used for the cross-section sensitivity and uncertainty calculations. These studies are useful for the interpretation of the experimental measurements, in particular to assess the uncertainties linked to the basic nuclear data. The TPR, the neutron activation rates and the associated uncertainties were determined using the EFF-3.0 9 Be nuclear cross section and covariance data, and compared with those from other evaluations, like FENDL-2.1. Sensitivity profiles and nuclear data uncertainties of the TPR and detector reaction rates with respect to the cross-sections of 9 Be, 6 Li, 7 Li, O and C were determined at different positions in the experimental block. (author)

Microscopic approach to the theory of light nuclei and to simple nuclear reactions

International Nuclear Information System (INIS)

Baz', L.I.; Filippov, G.F.

1976-01-01

The results of calculations for the properties of light nuclei and simple nuclear reactions using the Schrodinger multinucleon equation involving the realistic nucleon-nucleon interaction are reviewed. It is noted that the theory for the A(<=)4 nuclei is practically complete at present. The reasons for the good agreement between the theoretical and experimental cross sections of nuclear reactions are given. The programme of a correct separation of the nuclear collective degree of freedom are discussed in detail

Nuclear halo and its related reactions

International Nuclear Information System (INIS)

Zhang Huanqiao

2005-01-01

In order to search proton halo, the reaction cross sections of 27,28 P, 29 S and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at Z=15. The experimental results for the isotones with Z=14 as well as 28 P can be well described by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross sections for 28 P could be explained in the modified Glauber theory with an enlarged core. Theoretical analysis with the modified Glauber theory of the optical limit and few-body approaches underpredicted the experimental data of 27 P. Our theoretical analysis shows that an enlarged core together with proton halo is probably the mechanism responsible for the enhancement of the cross sections for the reaction of 27 P+ 28 Si. In addition, we find from the experimental results that 29 S may have a moderate proton halo structure. Except the nuclei near or at drop-lines, halo may appear in the excited states of stable nuclei. By means of the asymptotic normalization coefficients (ANC's) extracted from transfer reactions of 11 B(d, p) 12 B, 12 C(d, p) 13 C, and H( 6 He, n) 6 Li, we have verified that the second ( Jπ = 2 - ) and third (Jπ = 1 - ) excited states in 12 B and the first (Jπ =1/2 + ) excited state in 13 C are the neutron halo states, while the second excited state (3.56 MeV, Jπ = 0 + ) in 6 Li is a proton-neutron halo state. We have proposed a procedure to extract the probability for valence particle being out of the binding potential from the measured nuclear asymptotic normalization coefficients. With this procedure, available data regarding the nuclear halo candidates are systematically analyzed and a number of halo nuclei are confirmed. Based on these results we have got a much relaxed condition for nuclear halo occurrence. Furthermore, we have presented the scaling laws for the dimensionless quantity 2 >/R 2 of

Dependence of ICF reaction dynamics on target structure

International Nuclear Information System (INIS)

Kumar, Kamal; Dutt, Sunil; GulI, Muntazir; Ahmad, Tauseef; Rizvi, I.A.; Ali, Sabir; Agarwal, Avinash; Kumar, R.; Chaubey, A.K.

2016-01-01

The projectile structure is also found responsible for the ICF reaction processes. It is found that projectile having bigger alpha cluster is more unstable towards break up. In this context, a comparative study of 12 C and 16 O ion-beams induced reactions with different targets has been done. The deduced ICF contributions for different systems have been plotted against the target charge of different targets. It is observed that target properties may also be responsible for the interplay between CF and ICF reaction dynamics

Experimental Observation of Nuclear Reactions in Palladium and Uranium

International Nuclear Information System (INIS)

J. Dufour; D. Murat; X. Dufour; J. Foos

2001-01-01

By submitting various metals (Pd, U) containing hydrogen (from 2000 to 700 000 atoms of hydrogen for 1 000 000 atoms of the host metal) to the combined action of electrical currents and magnetic fields, we have observed a sizeable exothermal effect (from 0.1 to 8 W for 500 mg of metal used). This effect is beyond experimental errors, the energy output being typically 130 to 250% of the energy input and not of chemical origin (exothermal effect in the range of 7000 MJ/mol of metal in the case of palladium and of 60 MJ/mol in the case of uranium). New chemical species also appear in the processes metals. It has been shown by a QED calculation that resonances of long lifetime (s), nuclear dimensions (fm), and low energy of formation (eV) could exist. This concept seems to look like the 'shrunken hydrogen atoms' proposed by various authors. It is indeed very different in two ways (a) being a metastable state, it needs energy to be formed (a few eV) and reverts to normal hydrogen after a few seconds, liberating back its energy of formation (it is thus not the source of the energy observed); (b) its formation can be described as the electron spin/proton nuclear spin interaction becoming first order in the lattice environment (whereas it is third order in a normal hydrogen atom). Moreover, we consider that the hydrex cannot yield a neutron because this reaction is strongly endothermic. To explain our results, we put forward the following working hypothesis: In a metal lattice and under proper conditions, the formation of such resonances (metastable state) could be favored. We propose to call them HYDREX, and we assume that they are actually formed in cold fusion (CF) and low-energy nuclear reaction (LENR) experiments. Once formed, a number of HYDREX could gather around a nucleus of the lattice to form a cluster of nuclear size and of very long life time compared to nuclear time (10 -22 s). In this cluster, nuclear rearrangements could take place, yielding mainly 4 He

Gas stratification break-up by a vertical jet: Simulations using the GOTHIC code

International Nuclear Information System (INIS)

Andreani, Michele; Kapulla, Ralf; Zboray, Robert

2012-01-01

Highlights: ► Simulations of experiments addressing helium stratification break-up with GOTHIC are presented. ► In the tests, the initial helium-rich layer in a large vessel is eroded by a vertical jet. ► A 3-D coarse mesh and various finer 2-D meshes have been used for the simulations. ► In general, the 3-D calculations predict too slow mixing in the vessel. ► A reasonable agreement between calculated and measured gas concentrations requires a fine mesh. - Abstract: The capability assessment of three-dimensional computational tools to predict the erosion and the break-up of stratified conditions that can build-up in a containment through the release of hydrogen during an early phase of a hypothetical severe accident is the focus of intense research worldwide. In conjunction with the OECD SETH-2 project, the GOTHIC code is assessed against experiments in which mass and/or heat sources or sinks cause mixing. This paper reports on simulation results of selected experiments where the initial helium stratification in a vessel is eroded by a vertical jet originating from an injection below the initial density interface. A 3-D coarse mesh, as well as various finer 2-D meshes, is used to simulate the evolution of the helium distribution generated by jets having different initial momentum. In general, the 3-D calculations predict too slow mixing in the vessel and a reasonable agreement between calculated and measured gas concentrations can only be achieved with a sufficiently fine mesh. These results can be explained by comparing the calculated velocity field with that measured using the PIV technique, which also provides valuable insight into the mechanisms of the interaction between the jet and the density interface.

Applying some methods to process the data coming from the nuclear reactions

International Nuclear Information System (INIS)

Suleymanov, M.K.; Abdinov, O.B.; Belashev, B.Z.

2010-01-01

Full text : The methods of a posterior increasing the resolution of the spectral lines are offered to process the data coming from the nuclear reactions. The methods have applied to process the data coming from the nuclear reactions at high energies. They give possibilities to get more detail information on a structure of the spectra of particles emitted in the nuclear reactions. The nuclear reactions are main source of the information on the structure and physics of the atomic nuclei. Usually the spectrums of the fragments of the reactions are complex ones. Apparently it is not simple to extract the necessary for investigation information. In the talk we discuss the methods of a posterior increasing the resolution of the spectral lines. The methods could be useful to process the complex data coming from the nuclear reactions. We consider the Fourier transformation method and maximum entropy one. The complex structures were identified by the method. One can see that at lest two selected points are indicated by the method. Recent we presented a talk where we shown that the results of the analyzing the structure of the pseudorapidity spectra of charged relativistic particles with ≥ 0.7 measured in Au+Em and Pb+Em at AGS and SPS energies using the Fourier transformation method and maximum entropy one. The dependences of these spectra on the number of fast target protons were studied. These distribution shown visually some plateau and shoulder that was at least three selected points on the distributions. The plateaus become wider in PbEm reactions. The existing of plateau is necessary for the parton models. The maximum entropy method could confirm the existing of the plateau and the shoulder on the distributions. The figure shows the results of applying the maximum entropy method. One can see that the method indicates several clean selected points. Some of them same with observed visually ones. We would like to note that the Fourier transformation method could not

High vacuum general purpose scattering chamber for nuclear reaction study

International Nuclear Information System (INIS)

Suresh Kumar; Ojha, S.C.

2003-01-01

To study the nuclear reactions induced by beam from medium energy accelerators, one of the most common facility required is a scattering chamber. In the scattering chamber, projectile collides with the target nucleus and the scattered reaction products are detected with various type of nuclear detector at different angles with respect to the beam. The experiments are performed under high vacuum to minimize the background reaction and the energy losses of the charged particles. To make the chamber general purpose various requirement of the experiments are incorporated into it. Changing of targets, changing angle of various detectors while in vacuum are the most desired features. The other features like ascertaining the beam spot size and position on the target, minimizing the background counts by proper beam dump, accurate positioning of the detector as per plan etc. are some of the important requirements

Analysis by nuclear reactions and activations. A current bibliography

International Nuclear Information System (INIS)

Bujdoso, E.

2001-01-01

A current bibliography based on INIS Atomindex with 78 references on Analysis by nuclear reactions and activations has been prepared for year 1998. References are arranged by first authors' name. (N.T.)

Analysis of fluorine by nuclear reactions and applications to human dental enamel

International Nuclear Information System (INIS)

Stroobants, J.; Bodart, F.; Deconninck, G.; Demortier, G.; Nicolas, G.

Nuclear reactions induced on Fluorine by low energy protons are investigated, thick target excitation yield curves and tables for 19 F(p,p'γ) 19 F and 19 F(p,αγ) 16 O reactions are given between 0.3 and 2.5 MeV. Interferences from other nuclear reactions, detection limits and sensitivity for Fluorine detection are investigated. After a wide investigation of the repartition of Fluorine in tooth enamel it is concluded that there is an equilibrium of the concentrations between tooth and saliva which is rapidly restored after the perturbation introduced by the external treatments. (author)

Study of nuclear fuel burn-up

International Nuclear Information System (INIS)

Pavelescu, M.; Borza, M.

1975-01-01

The authors approach theoretical treatment of isotopic composition changement for nuclear fuel in nuclear reactors. They show the difficulty of exhaustive treatment of burn-up problems and introduce the principal simplifying principles. Due to these principles they write and solve analytically the evolution equations of the concentration for the principal nuclides both in the case of fast and thermal reactors. Finally, they expose and comment the results obtained in the case of a power fast reactor. (author)

Experimental Guidance of ISB Corrections via Direct Nuclear Reactions

Science.gov (United States)

Leach, K. G.; Garrett, P. E.; Ball, G. C.; Bangay, J. C.; Bianco, L.; Demand, G. A.; Faestermann, T.; Finlay, P.; Green, K. L.; Hertenberger, R.; Kriicken, R.; Phillips, A. A.; Rand, E. T.; Sumithrarachchi, C. S.; Svensson, C. E.; Towner, I. S.; Triambak, S.; Wirth, H.-F.; Wong, J.

2011-09-01

The most recent isospin-symmetry-breaking corrections, δc, of Towner and Hardy for superallowed Fermi β-decay transitions, have included the opening of specific core orbitals. This change has resulted in significant deviations in some of the δc factors from their previous calculations, and an improved agreement of the individual corrected Script Ft values with the overall world average of the 13 most precise cases. While this is consistent with the conserved-vector-current (CVC) hypothesis of the Standard Model, these new calculations must be thoroughly tested, and guidance must be given for the improvement of calculations for the upper-pf shell nuclei. Using the (d,t) reaction mechanism to probe the single neutron wavefunction overlap, information regarding the relevant shell-model configurations needed in the calculation can be determined. An experiment was therefore performed with a 22 MeV polarized deuterium beam from the MP tandem Van de Graaff accelerator in Munich, Germany. Using the Q3D magnetic spectrograph, and a cathode-strip focal-plane detector, outgoing tritons were analyzed at 9 angles between 10° and 60°, up to an excitation energy of 4.8 MeV. This proceeding reports the motivational and experimental details for the 64Zn(d,t)63Zn transfer work presented.

Nuclear power/water pumping-up composite power plant

International Nuclear Information System (INIS)

Okamura, Kiyoshi.

1995-01-01

In a nuclear power/water pumping-up composite power plant, a reversible pump for pumping-up power generation connected to a steam turbine is connected to an upper water reservoir and a lower water reservoir. A pumping-up steam turbine for driving the turbine power generator, a hydraulic pump for driving water power generator by water flowing from the upper water reservoir and a steam turbine for driving the pumping-up pump by steams from a nuclear reactor are disposed. When power demand is small during night, the steam turbine is rotated by steams of the reactor, to pump up the water in the lower water reservoir to the upper water reservoir by the reversible pump. Upon peak of power demand during day time, power is generated by the steams of the reactor, as well as the reversible pump is rotated by the flowing water from the upper water reservoir to conduct hydraulic power generation. Alternatively, hydraulic power generation is conducted by flowing water from the upper reservoir. Since the number of energy conversion steps in the combination of nuclear power generation and pumping-up power generation is reduced, energy loss is reduced and utilization efficiency can be improved. (N.H.)

Material property requirements for application leak-before-break technology on nuclear power plant high-energy piping

International Nuclear Information System (INIS)

Li Chengliang; Deng Xiaoyun; Yin Zhiying; Liu Meng

2012-01-01

The application of leak-before-break (LBB) technology on nuclear power plant high-energy piping systems can improve their safety and economy, while propose some new requirements on testing material properties. The U.S. Nuclear Regulatory Commission's LBB related standard review plan and implementation specifications were analyzed, and test items, object, temperature, quantity and thermal aging effect of five general requirements were summarized. In addition, four key testing technical requirements, such as specimen size, side grooves, strain range and the orientation of specimens were also discussed to ensure the test data usefulness, representativeness and integrity. This study can provide some guidance for the aforementioned test program on domestic materials. (authors)

Does the association between broken partnership and first time myocardial infarction vary with time after break-up?

DEFF Research Database (Denmark)

Kriegbaum, Margit; Christensen, Ulla; Andersen, Per Kragh

2013-01-01

Marriage is associated with lower risk of coronary heart disease, but it is unknown if the association depends on time since break-up with a partner. In this study we included both married and unmarried couples to study if the association between broken partnership (BP) and first time incident...

Nuclear momentum distribution and relativistic heavy-ion reactions

International Nuclear Information System (INIS)

Wong, C.Y.; Blankenbecler, R.

1980-01-01

In terms of a direct fragmentation process and a hard-scattering process, the proton-inclusive data for the reaction α + 12 C → p + X have been successfully analyzed. The extracted semiempirical momentum distribution indicates possible evidence of nuclear correlations and final-state interactions. 4 figures

'Level-level correlation and absorption in nuclear reactions'

International Nuclear Information System (INIS)

Hussein, M.S.

Level-level correlation (LLC) in nuclear reactions is discussed in general and it is shown that in the presence of LLC, N sub(μ) = Σ/g μa/ 2 > divided by gamma μ T tilde, where T tilde is the average absorption in the eigen channels [pt

International reactions after the resumption of nuclear tests: lot of noise for nothing?

International Nuclear Information System (INIS)

Montesquieu, E. de

1996-01-01

In 1995, the French President announced that France would perform an ultimate campaign of nuclear tests before a complete banishment as soon as spring 1996. The campaign effectively ended on time and six tests took place between September 5, 1995 and January 27, 1996. The disarmament process went on and the international negotiations in progress at that time were not affected by the French policy. However, this campaign has caused a strong emotion, if not in the entire World, at least in part of the planet and in particular in Western Europe. This report analyses the reactions from the different governments and from the public opinion and shows their impact on the French diplomacy. Content: Part 1 - general considerations: 1 - lot of noise for nothing?: the objectives of French diplomacy; the acts (a quasi lack of sanctions, a temporary degradation of our relations with a limited number of countries); the rhetoric (diplomatic regrets in first time, slip-ups in the second time, the public opinion weight); 2 - the lessons learnt: the opinion and the management of the foreign policy (the image of France, the communication fight); the geopolitical lessons (European Union: community solidarity and European defense; the South Pacific area); 3 - a case study: Japan: the time of uncertainties (domestic situation, external policy); the Japanese reactions after the tests resumption. Part 2 - synthesis of reactions after the resumption of nuclear tests by France: Pacific bordering countries (South Pacific, Latin America); Western Europe countries; non-European countries; Conclusions

Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

International Nuclear Information System (INIS)

Pizzone, R.G.; La Cognata, M.; Rinollo, A.; Spitaleri, C; Sparta, R.; Bertulani, C.A.; Mukhamedzhanov, A.M.; Blokhintsev, L.; Lamia, L.; Tumino, A.

2014-01-01

The basic idea of the Trojan Horse Method (THM) is to extract the cross section in the low-energy region of a two-body reaction with significant astrophysical impact: a + x → c + C from a suitable quasi-free (QF) break-up of the so called Trojan Horse nucleus, e.g. A=x (+) s where usually x is referred to as the participant and s as the spectator particle. In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was therefore tested using the quasi free 2 H( 6 Li, pt) 4 He and 2 H( 3 He,pt)H reactions after 6 Li and 3 He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. Polynomial fits were then performed on the data giving S 0 = (75 ± 21) keV*b in the case of the 6 Li break-up, while for 3 He one obtains S 0 = (58 ± 2) keV*b. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case

Resonant Electromagnetic Interaction in Low Energy Nuclear Reactions

Science.gov (United States)

Chubb, Scott

2008-03-01

Basic ideas about how resonant electromagnetic interaction (EMI) can take place in finite solids are reviewed. These ideas not only provide a basis for conventional, electron energy band theory (which explains charge and heat transport in solids), but they also explain how through finite size effects, it is possible to create many of the kinds of effects envisioned by Giuliano Preparata. The underlying formalism predicts that the orientation of the external fields in the SPAWAR protocolootnotetextKrivit, Steven B., New Energy Times, 2007, issue 21, item 10. http://newenergytimes.com/news/2007/NET21.htm^,ootnotetextSzpak, S.; Mosier-Boss, P.A.; Gordon, F.E. Further evidence of nuclear reactions in the Pd lattice: emission of charged particles. Naturwissenschaften 94,511(2007)..has direct bearing on the emission of high-energy particles. Resonant EMI also implies that nano-scale solids, of a particular size, provide an optimal environment for initiating Low Energy Nuclear Reactions (LENR) in the PdD system.

The mechanism of break-up reactions of light ions at non-relativistic and relativistic energies

International Nuclear Information System (INIS)

Baur, G.; Hoffmann, B.; Rosel, F.; Trautmann, D.; Shyam, R.

1984-01-01

Fragmentation processes is nuclear collisions are reviewed. The authors consider a three-body model, where a projectile a=b+x interacts with a target nucleus A. The interaction is described by means of optical potentials V/sub Aa/, V/sub Ab/ and V/sub Ax/ respectively. The projectile a is composed of two subsystems b (''spectator'') and x (''participant'') bound together by V/sub bx/

The heavy-ion total reaction cross-section and nuclear transparancy

International Nuclear Information System (INIS)

Rego, R.A.; Hussein, M.S.

1982-10-01

The total reaction cross section of heavy ions at intermediate energies is discussed. The special role played by the individual nucleon-nucleon collisions in determining the nuclear transparancy is analysed. Several competing effects arising from the nuclear and Coulomb interactions between the two ions are found to be important in determing σ sub(R) at lower energies. (Author) [pt

The heavy-ion total reaction cross-section and nuclear transparency

International Nuclear Information System (INIS)

Rego, R.A.; Hussein, M.S.

1982-01-01

The total reaction cross section of heavy ions at intermediate energies is discussed. The special role played by the individual nucleon-nucleon collisions in determining the nuclear transparency is analysed. Several competing effects arising from the nuclear and Coulomb interactions between the two ions are found to be important in determining σ(sub R) at lower energies. (Author) [pt

Development of utility system of charged particle Nuclear Reaction Data on Unified Interface

International Nuclear Information System (INIS)

Aoyama, Shigeyoshi; Ohbayashi, Yosihide; Kato, Kiyoshi; Masui, Hiroshi; Ohnishi, Akira; Chiba, Masaki

1999-01-01

We have developed a utility system, WinNRDF, for a nuclear charged particle reaction data of NRDF (Nuclear Reaction Data File) on a unified interface of Windows95, 98/NT. By using the system, we can easily search the experimental data of a charged particle reaction in NRDF and also see the graphic data on GUI (Graphical User Interface). Furthermore, we develop a mechanism of making a new index of keywords in order to include the time developing character of the NRDF database. (author)

Nuclear reactions: public attitudes and policies toward nuclear power

International Nuclear Information System (INIS)

Freudenburg, W.R.; Baxter, R.K.

1985-01-01

The declining public support for nuclear power has political costs. In the wake of the Three Mile Island accident, public trust in the nuclear industry has reached an all-time low. Recognition of this lack of trust sets up a counterweight to the industry pressures for relaxed regulation. The authors present the historical background behind the current debate, then summarize the available scientific survey data on the actual levels and trends in public attitudes. They find little reason for optimism. With the exception of gender, most demographic factors have only modest influence on nuclear power attitudes, which suggests that public uneasiness about the technology has become a fact of life. They conclude that a significant weakening of federal safety standards would not be consistent with public preferences. 49 references, 3 figures

New findings on the onset of thermal disassembly in spallation reactions