WorldWideScience

Sample records for intermediate energy fission

  1. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  2. Fission cross section measurements at intermediate energies

    International Nuclear Information System (INIS)

    Laptev, Alexander

    2005-01-01

    The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)

  3. Fission cross sections in the intermediate energy region

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for 235 U and 238 U compared to intranuclear cascade and statistical model predictions

  4. Fission cross sections in the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J. (Los Alamos National Lab., NM (USA)); Carlson, A.D.; Wasson, O.A. (National Inst. of Standards and Technology, Gaithersburg, MD (USA)); Hill, N.W. (Oak Ridge National Lab., TN (USA))

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for {sup 235}U and {sup 238}U compared to intranuclear cascade and statistical model predictions.

  5. Rupturing the hemi-fission intermediate in membrane fission under tension: Reaction coordinates, kinetic pathways, and free-energy barriers

    Science.gov (United States)

    Zhang, Guojie; Müller, Marcus

    2017-08-01

    Membrane fission is a fundamental process in cells, involved inter alia in endocytosis, intracellular trafficking, and virus infection. Its underlying molecular mechanism, however, is only incompletely understood. Recently, experiments and computer simulation studies have revealed that dynamin-mediated membrane fission is a two-step process that proceeds via a metastable hemi-fission intermediate (or wormlike micelle) formed by dynamin's constriction. Importantly, this hemi-fission intermediate is remarkably metastable, i.e., its subsequent rupture that completes the fission process does not occur spontaneously but requires additional, external effects, e.g., dynamin's (unknown) conformational changes or membrane tension. Using simulations of a coarse-grained, implicit-solvent model of lipid membranes, we investigate the molecular mechanism of rupturing the hemi-fission intermediate, such as its pathway, the concomitant transition states, and barriers, as well as the role of membrane tension. The membrane tension is controlled by the chemical potential of the lipids, and the free-energy landscape as a function of two reaction coordinates is obtained by grand canonical Wang-Landau sampling. Our results show that, in the course of rupturing, the hemi-fission intermediate undergoes a "thinning → local pinching → rupture/fission" pathway, with a bottle-neck-shaped cylindrical micelle as a transition state. Although an increase of membrane tension facilitates the fission process by reducing the corresponding free-energy barrier, for biologically relevant tensions, the free-energy barriers still significantly exceed the thermal energy scale kBT.

  6. Proton induced fission of {sup 232}Th at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Gikal, K. B., E-mail: kgikal@mail.ru; Kozulin, E. M.; Bogachev, A. A. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Burtebaev, N. T.; Edomskiy, A. V. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Itkis, I. M.; Itkis, M. G.; Knyazhev, G. N. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Kovalchuk, K. V.; Kvochkina, T. N. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Piasecki, E. [Heavy Ion Laboratory of Warsaw University (Poland); Rubchenya, V. A. [University of Jyväskylä, Department of Physics (Finland); Sahiev, S. K. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Trzaska, W. H. [University of Jyväskylä, Department of Physics (Finland); Vardaci, E. [INFN Napoli, Dipartimento di Scienze Fisiche dell’Università di Napoli (Italy)

    2016-12-15

    The mass-energy distributions and cross sections of proton-induced fission of {sup 232}Th have been measured at the proton energies of 7, 10, 13, 20, 40, and 55 MeV. Experiments were carried out at the proton beam of the K-130 cyclotron of the JYFL Accelerator Laboratory of the University of Jyväskylä and U-150m cyclotron of the Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan. The yields of fission fragments in the mass range A = 60–170 a.m.u. have been measured up to the level of 10−4%. The three humped shape of the mass distribution up has been observed at higher proton energies. The contribution of the symmetric component grows up with increasing proton incident energy; although even at 55 MeV of proton energy the shoulders in the mass energy distribution clearly indicate the asymmetric fission peaks. Evolution of shell structure was observed in the fission fragment mass distributions even at high excitation energy.

  7. Systematics of fission cross sections at the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)

  8. Unified description of neutron-, proton- and photon-induced fission cross sections in intermediate energy region

    International Nuclear Information System (INIS)

    Fukahori, Tokio; Iwamoto, Osamu; Chiba, Satoshi

    2003-01-01

    For an accelerator-driven nuclear waste transmutation system, it is very important to estimate sub-criticality of core system for feasibility and design study of the system. The fission cross section in the intermediate energy range has an important role. A program FISCAL has been developed to calculate neutron-, proton- and photon-induced fission cross sections in the energy region from several tens of MeV to 3 GeV. FISCAL adopts the systematics considering experimental data for Ag- 243 Am. It is found that unified description of neutron-, proton- and photon-induced fission cross sections is available. (author)

  9. Photon and proton induced fission on heavy nuclei at intermediate energies

    Directory of Open Access Journals (Sweden)

    Andrade-II E.

    2014-04-01

    Full Text Available We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241Am, 238U, and 237Np targets and the Bremmstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232Th and 238U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments.

  10. Angular distribution of fragments from neutron-induced fission of 238U in the intermediate energy region

    International Nuclear Information System (INIS)

    Carlsson, Magnus

    2004-06-01

    Areas ranging from nuclear structure models to accelerator-driven systems benefit from improved neutron-induced fission data in the intermediate energy region. In this Master's degree thesis, the fragment angular distribution from fission of 238 U, induced by 21-MeV neutrons, has been analysed from an experiment performed with the Medley/DIFFICILE setup at the The Svedberg Laboratory in Uppsala. The data have been corrected for low energy neutrons in the beam. The results agree with other experiments, as well as with model calculations. The data should be a starting point for further analysis with a goal to deduce the fission cross-section of 238 U

  11. Fission of intermediate mass nuclei by bremsstrahlung photons in the energy range 0.8-1.8 GeV

    International Nuclear Information System (INIS)

    Lima, D.A. de.

    1983-01-01

    The fission of intermediate mass nuclei in the Al-Ta internal induced by bremsstrahlung photons of maximum energies between 0,8 to 1,8 GeV is studied. Thin targets of Nd and Sm and dense targets of Al,Ti,Co,Zr,Nb,Ag,In and Ta are utilized, and all the aspects related with the fission fragment absorption by the targets themselves are considered. The samples are exposed in th 2,5 GeV Electron Synchrotron at Bonn University. Muscovite mica, CR-39 and makrofol are used as fission fragments detectors. Fission cross sections and nuclear fissionabilities of the studied elements are estimated. (L.C.) [pt

  12. Fission cross section and fission fragment angular distribution for oriented nucleus fission by intermediate energy neutrons (epsilon < or approximately 1 Mev)

    International Nuclear Information System (INIS)

    Barabanov, A.L.; Grechukhin, D.P.

    1985-01-01

    General analysis is conducted, and formulae for fission cross section and angular distribution of fission fragments of oriented nuclei by fast neutrons are presented. Geometrical coefficients making up the formulae permitting to carry out calculations for target nuclei with spins I=3/2, 5/2, 7/2 at interaction energies epsilon < or approximately 1 MeV are tabulated. Results of demonstrative calculation of fission fragment angular distribution of oriented sup(235)U nuclei by 0.1 <= epsilon <= 1.0 MeV neutrons reveal that angular distribution weakly depends on the set of permeability factors of neutron waves applied in the calculations

  13. Angular distribution of fragments from neutron-induced fission of {sup 238}U in the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Magnus

    2004-06-01

    Areas ranging from nuclear structure models to accelerator-driven systems benefit from improved neutron-induced fission data in the intermediate energy region. In this Master's degree thesis, the fragment angular distribution from fission of {sup 238}U, induced by 21-MeV neutrons, has been analysed from an experiment performed with the Medley/DIFFICILE setup at the The Svedberg Laboratory in Uppsala. The data have been corrected for low energy neutrons in the beam. The results agree with other experiments, as well as with model calculations. The data should be a starting point for further analysis with a goal to deduce the fission cross-section of {sup 238}U.

  14. Theoretical and experimental studies of the neutron rich fission product yields at intermediate energies

    Directory of Open Access Journals (Sweden)

    Äystö J.

    2012-02-01

    Full Text Available A new method to measure the fission product independent yields employing the ion guide technique and a Penning trap as a precision mass filter, which allows an unambiguous identification of the nuclides is presented. The method was used to determine the independent yields in the proton-induced fission of 232Th and 238U at 25 MeV. The data were analyzed with the consistent model for description of the fission product formation cross section at the projectile energies up to 100 MeV. Pre-compound nucleon emission is described with the two-component exciton model using Monte Carlo method. Decay of excited compound nuclei is treated within time-dependent statistical model with inclusion of the nuclear friction effect. The charge distribution of the primary fragment isobaric chain was considered as a result of frozen quantal fluctuations of the isovector nuclear density. The theoretical predictions of the independent fission product cross sections are used for normalization of the measured fission product isotopic distributions.

  15. Fission Fragment Mass Distributions and Total Kinetic Energy Release of 235-Uranium and 238-Uranium in Neutron-Induced Fission at Intermediate and Fast Neutron Energies

    Energy Technology Data Exchange (ETDEWEB)

    Duke, Dana Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-12

    This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of 235U and 238U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fission measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.

  16. Measurement of Fragment Mass Distributions in Neutron-induced Fission of 238U and 232Th at Intermediate Energies

    International Nuclear Information System (INIS)

    Simutkin, V.D.

    2008-01-01

    Conceptual analysis of accelerator-driven systems assumes extensive use of nuclear data on neutron-induced reactions at intermediate energies. In particular, information about the fission fragment yields from the 238 U(n,f) and 232 Th(n,f) reactions is of particular interest at neutron energies from 10 to 200 MeV. However, there is a lack of such data for both 238 U and 232 Th. Up to now, the intermediate energy measurements have been performed for 238 U only, and there are no data for the 232 Th(n,f) reaction. The aim of the work is to provide such data. Fission fragment mass distributions for the 232 Th(n,f) and 238 U(n,f) reactions have been measured for the incident neutron energies 32.8 MeV, 45.3 MeV and 59.9 MeV. The experiments have been performed at the neutron beam facility of the Universite Catholique de Louvain, Belgium. A multi-section Frisch-gridded ionization chamber has been used as a fission fragment detector. The data obtained have been interpreted in terms of the multimodal random neck-rupture model (MMRNRM). (authors)

  17. Anisotropy of the fission fragments from neutron-induced fission in the intermediate energy range of 1-200 MeV

    Science.gov (United States)

    Vorobyev, A. S.; Gagarski, A. M.; Shcherbakov, O. A.; Vaishnene, L. A.; Barabanov, A. L.

    2015-08-01

    Angular distributions of fission fragments from the neutron-induced fission of 232Th, 235U, and 238U have been measured in the energy range 1-200 MeV at the neutron time-of-flight (TOF) spectrometer GNEIS using position sensitive multiwire proportional counters as fission fragment detector. A short description of the experimental equipment and measurement procedure is given. The anisotropy of fission fragments deduced from the data on measured angular distributions is presented in comparison with experimental data of other authors.

  18. Energy released in fission

    International Nuclear Information System (INIS)

    James, M.F.

    1969-05-01

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  19. Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1–200 MeV

    OpenAIRE

    Vorobyev Alexander S.; Gagarski Alexei M.; Shcherbakov Oleg A.; Vaishnene Larisa A.; Barabanov Alexei L.

    2017-01-01

    Angular distributions of fission fragments from the neutron-induced fission of 232Th, 233U, 235U, 238U and 209Bi have been measured in the energy range 1–200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the PNPI (Gatchina, Russia). The multiwire proportional counters have been used as a position sensitive fission fragment detector. A description of the experimental equipment and measurement procedure is given. The anisotr...

  20. Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1-200 MeV

    Science.gov (United States)

    Vorobyev, Alexander S.; Gagarski, Alexei M.; Shcherbakov, Oleg A.; Vaishnene, Larisa A.; Barabanov, Alexei L.

    2017-09-01

    Angular distributions of fission fragments from the neutron-induced fission of 232Th, 233U, 235U, 238U and 209Bi have been measured in the energy range 1-200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the PNPI (Gatchina, Russia). The multiwire proportional counters have been used as a position sensitive fission fragment detector. A description of the experimental equipment and measurement procedure is given. The anisotropy of fission fragments deduced from the data on measured angular distributions is presented in comparison with experimental data of other authors, first of all, the recent data from WNR at LANSCE (Los Alamos, USA) and n_TOF(CERN).

  1. Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1–200 MeV

    Directory of Open Access Journals (Sweden)

    Vorobyev Alexander S.

    2017-01-01

    Full Text Available Angular distributions of fission fragments from the neutron-induced fission of 232Th, 233U, 235U, 238U and 209Bi have been measured in the energy range 1–200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the PNPI (Gatchina, Russia. The multiwire proportional counters have been used as a position sensitive fission fragment detector. A description of the experimental equipment and measurement procedure is given. The anisotropy of fission fragments deduced from the data on measured angular distributions is presented in comparison with experimental data of other authors, first of all, the recent data from WNR at LANSCE (Los Alamos, USA and n_TOF(CERN.

  2. Measurement of Fragment Mass Distributions in Neutron-induced Fission of {sup 238}U and {sup 232}Th at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Simutkin, V.D. [Uppsala University, P.O Box 525, SE-751 20 Uppsala (Sweden)

    2008-07-01

    Conceptual analysis of accelerator-driven systems assumes extensive use of nuclear data on neutron-induced reactions at intermediate energies. In particular, information about the fission fragment yields from the {sup 238}U(n,f) and {sup 232}Th(n,f) reactions is of particular interest at neutron energies from 10 to 200 MeV. However, there is a lack of such data for both {sup 238}U and {sup 232}Th. Up to now, the intermediate energy measurements have been performed for {sup 238}U only, and there are no data for the {sup 232}Th(n,f) reaction. The aim of the work is to provide such data. Fission fragment mass distributions for the {sup 232}Th(n,f) and {sup 238}U(n,f) reactions have been measured for the incident neutron energies 32.8 MeV, 45.3 MeV and 59.9 MeV. The experiments have been performed at the neutron beam facility of the Universite Catholique de Louvain, Belgium. A multi-section Frisch-gridded ionization chamber has been used as a fission fragment detector. The data obtained have been interpreted in terms of the multimodal random neck-rupture model (MMRNRM). (authors)

  3. Influence of multichance fission on fragment angular anisotropy in the 232Th( n,f) and 238U( n,f) reactions at intermediate energies

    Science.gov (United States)

    Ryzhov, I. V.; Onegin, M. S.; Tutin, G. A.; Blomgren, J.; Olsson, N.; Prokofiev, A. V.; Renberg, P.-U.

    2005-10-01

    Fission fragment angular distributions have been measured for the 232Th( n,f) and 238U( n,f) reactions in the neutron energy range 20-100 MeV. The fragment angular anisotropy for 232Th was found to be systematically larger than that for 238U. The obtained results have been analyzed in the framework of the statistical saddle-point model combined with pre-equilibrium and Hauser-Feshbach calculations of partial fission cross sections. The calculations have revealed that fission following multiple neutron emission takes place in both reactions, resulting in a considerable contribution of high chances to the total fission fragment angular anisotropy. This gives grounds to expect that the observed difference is mainly due to nuclei fissioning at the end of the neutron evaporation chain.

  4. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1982-02-01

    In these lectures we present the liquid drop model of fission and compare some of its prediction with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. We then discuss, using the example of the oscillator model, the generality of shell effects. We show how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  5. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1980-08-01

    In these lectures the liquid drop model of fission is presented and some of its predictions compared with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. It is shown how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  6. Analysis of dependence of fission cross section and angular anisotropy of the 235U fission fragment escape induced by neutrons of intermediate energies (epsilon < or approximately200 keV) on target nucleus orientation

    International Nuclear Information System (INIS)

    Barabanov, A.L.

    1985-01-01

    Experimental data on dependence of fission cross section Σsub(f) (epsilon) and angular anisotropy W(epsilon, 0 deg)/W(epsilon, 90 deg) of sup(235)U fission fragment escape by neutrons with energy epsilon=100 and 200 keV on orientation of target nuclei are analyzed. 235 U (Isup(πsub(0))=7/2sup(-)) nuclei were orientated at the expense of interaction of quadrupole nucleus momenta with nonuniform electric field of uranyl-rubidium nitrate crystal at crystal cooling to T=0.2 K. The analysis was carried out with three different sets of permeability factors T(epsilon). Results of the analysis weakly depend on T(epsilon) choice. It is shown that a large number of adjusting parameters (six fissionabilities γsup(f)(Jsup(π), epsilon) and six momenta sub(Jsup(π))) permit to described experimental data on Σsub(f)(epsilon) and W(epsilon, 0 deg)/W(epsilon, 90 deg), obtained at epsilon=200 keV by introducing essential dependence of γsup(f)(Jsup(π), epsilon) and sub(Jsup(π)) on Jsup(π). Estimations of fission cross sections Σsub(f)(epsilon) and angular distribution W(epsilon, n vector) up to T approximately equal to 0.01 K in two geometries of the experiment: the orientation axis is parallel and perpendicular to momentum direction p vector of incident neutrons, are conducted

  7. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    excitation energy, similar to the temperature dependence of the two-body friction. A sys- tematic study was also carried out by Bhattacharya et al [20]: the values of viscosity coefficient used to reproduce the observed neutron multiplicities increase with the mass and the excitation energy per nucleon of the composite system ...

  8. Mechanism of intermediate mass fragment emission at low energy

    International Nuclear Information System (INIS)

    Dhara, A.K.; Bhattacharya, C.; Bhattacharya, S.; Krishan, K.

    1993-01-01

    The study of the dynamics of intermediate mass fragment emission in fusion-fission processes has been carried out. The average kinetic energies and relative yield ratio of different fragments are calculated and compared with experimental values

  9. Nuclear dissipation effects on fission and evaporation in systems of intermediate fissility

    Directory of Open Access Journals (Sweden)

    Gelli N.

    2010-03-01

    Full Text Available The systems of intermediate fissility 132Ce and 158Er have been studied experimentally and theoretically in order to investigate the dissipation properties of nuclear matter. Cross sections of fusion-fission and evaporation residues channels together with charged particles multiplicities in both channels, their spectra, angular correlations and mass-energy distribution of fission fragments have been measured. Theoretical analysis has been performed using multi-dimensional stochastic approach with realistic treatment of particle evaporation. The results of analysis show that full one-body or unusually strong two-body dissipation allows to reproduce experimental data. No temperature dependent dissipation was needed.

  10. Angular distributions and anisotropy of the fragments from neutron-induced fission of 233U and 209Bi in the intermediate energy range of 1-200 MeV

    Science.gov (United States)

    Vorobyev, A. S.; Gagarski, A. M.; Shcherbakov, O. A.; Vaishnene, L. A.; Barabanov, A. L.

    2016-09-01

    New results of the neutron-induced fission experiments carried out at the neutron time-of-flight spectrometer GNEIS of the PNPI are given. Angular distributions of fission fragments from the neutron-induced fission of 233U and 209Bi nuclei have been measured in the energy range 1-200 MeV using position sensitive multiwire proportional counters as fission fragment detector. The recent improvements of the measurement and data processing procedures are described. The data on anisotropy of fission fragments deduced from the measured angular distributions are presented in comparison with the experimental data of other authors.

  11. Intermediate energy data

    International Nuclear Information System (INIS)

    Koning, A.J.; Fukahori, T.; Hasegawa, A.

    1998-01-01

    Subgroup 13 (SG13) on Intermediate Energy Nuclear data was formed by NEA Nuclear Science Committee to solve common problems of these types of data for nuclear applications. An overview is presented in this final report of the present activities of SG13, including data needs, high-priority nuclear data request list (nuclides), compilation of experimental data, specialists meetings and benchmarks, data formats and data libraries. Some important accomplishments are summarized, and recommendations are presented. (R.P.)

  12. Nuclear fission induced by high energy protons

    International Nuclear Information System (INIS)

    Barashenkov, V.S.; Shmakov, S.Yu.

    1979-01-01

    The fission of 203 Pb, 232 Th, 238 U, 239 Pu, 209 Br nuclei in the energy region T approximately equal to 0.1-2 GeV is considered on the basis of intranuclear cascade model. The competition between fission and evaporation of excited nuclei remaining after the cascade phase of the interaction is taken into account. Fong's model is used to calculate the fission process. The multiplicity of produced particles (d, t, 3 He, α), the energy spectra of neutrons, the distributions of residual nuclei are discussed. The calculated results are compared with the experiment and with the known theoretical data

  13. Energy from nuclear fission an introduction

    CERN Document Server

    De Sanctis, Enzo; Ripani, Marco

    2016-01-01

    This book provides an overview on nuclear physics and energy production from nuclear fission. It serves as a readable and reliable source of information for anyone who wants to have a well-balanced opinion about exploitation of nuclear fission in power plants. The text is divided into two parts; the first covers the basics of nuclear forces and properties of nuclei, nuclear collisions, nuclear stability, radioactivity, and provides a detailed discussion of nuclear fission and relevant topics in its application to energy production. The second part covers the basic technical aspects of nuclear fission reactors, nuclear fuel cycle and resources, safety, safeguards, and radioactive waste management. The book also contains a discussion of the biological effects of nuclear radiation and of radiation protection, and a summary of the ten most relevant nuclear accidents. The book is suitable for undergraduates in physics, nuclear engineering and other science subjects. However, the mathematics is kept at a level that...

  14. Langevin model of low-energy fission

    Science.gov (United States)

    Sierk, Arnold J.

    2017-09-01

    Background: Since the earliest days of fission, stochastic models have been used to describe and model the process. For a quarter century, numerical solutions of Langevin equations have been used to model fission of highly excited nuclei, where microscopic potential-energy effects have been neglected. Purpose: In this paper I present a Langevin model for the fission of nuclei with low to medium excitation energies, for which microscopic effects in the potential energy cannot be ignored. Method: I solve Langevin equations in a five-dimensional space of nuclear deformations. The macroscopic-microscopic potential energy from a global nuclear structure model well benchmarked to nuclear masses is tabulated on a mesh of approximately 107 points in this deformation space. The potential is defined continuously inside the mesh boundaries by use of a moving five-dimensional cubic spline approximation. Because of reflection symmetry, the effective mesh is nearly twice this size. For the inertia, I use a (possibly scaled) approximation to the inertia tensor defined by irrotational flow. A phenomenological dissipation tensor related to one-body dissipation is used. A normal-mode analysis of the dynamical system at the saddle point and the assumption of quasiequilibrium provide distributions of initial conditions appropriate to low excitation energies, and are extended to model spontaneous fission. A dynamical model of postscission fragment motion including dynamical deformations and separation allows the calculation of final mass and kinetic-energy distributions, along with other interesting quantities. Results: The model makes quantitative predictions for fragment mass and kinetic-energy yields, some of which are very close to measured ones. Varying the energy of the incident neutron for induced fission allows the prediction of energy dependencies of fragment yields and average kinetic energies. With a simple approximation for spontaneous fission starting conditions

  15. Fission energy program of the US Department of Energy, FY 1981

    International Nuclear Information System (INIS)

    1980-03-01

    Information is presented concerning the National Energy Plan and fission energy policy; fission energy program management; converter reactor systems; breeder reactor systems; and special nuclear evaluations and systems

  16. Fission energy program of the US Department of Energy, FY 1981

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Robert L.

    1980-03-01

    Information is presented concerning the National Energy Plan and fission energy policy; fission energy program management; converter reactor systems; breeder reactor systems; and special nuclear evaluations and systems.

  17. Measurement of fission fragments energy loss

    CERN Document Server

    Benetti, P; Calligarich, E; Cesana, A; Dolfini, R; Ioppolo, T; Raselli, G L; Terrani, M

    2002-01-01

    The mean energy of sup 2 sup 5 sup 2 Cf fission fragments emerging from an absorber and the determination of the capture rate in the absorber itself have been measured using two independent and complementary nuclear techniques. The results can be applied to the measurement of the energy self-absorption in a non-zero thickness source and can be used to validate simulation programs.

  18. Mass and Charge Distribution in Low-Energy Fission

    International Nuclear Information System (INIS)

    Wahl, A.C.

    1965-01-01

    The mass and charge distributions for thermal-neutron fission of U 235 are discussed in considerable detail and compared with the corresponding distributions in other low-energy fission processes. Points discussed in connection with the mass distributions for binary fission include the positions of the peaks, valley and fine structure in a mass yield curve with respect to filled nuclear shells and the changes in the positions that occur with changing fissioning nucleus and excitation energy. The mass distribution from ternary fission is discussed also. For both binary and ternary fission comments are made concerning the mass distributions of primary fragments (before neutron evaporation) and of fission products (after neutron evaporation). Charge distribution is discussed in terms of charge dispersion among fission products with the same mass number and the variation with mass number of Zp, the ''most probable charge'' (non-integral) for a given mass number. Although direct information about charge distribution is limited to fission products, estimates are presented of charge distribution for primary fission fragments. Knowledge and estimates of mass and charge distribution for a fission process allow estimation of primary yields of all fission products or fragments. Although many estimated primary yields are quite uncertain mainly because of lack of knowledge of charge distribution, especially for fission products formed in low yield; some estimates of primary yields are presented to illustrate the need for and possible practicality of further experimentation. Fission processes other than thermal-neutron fission of U 235 that are discussed include thermal-neutron fission of U 233 and Pu 239 , spontaneous fission of Pu 240 and Cf 252 , 14-MeV neutron fission of U 235 and U 238 , 11-MeV proton fission of Ra 226 and 22-MeV deuteron fission of Bi 209 . (author) [fr

  19. Outlook for nuclear fission energy

    International Nuclear Information System (INIS)

    Anderson, T.D.

    1978-01-01

    The electric utility industry has made a substantial commitment to nuclear power. The industrial capability to produce nuclear plants is large and well established. Nevertheless, nuclear energy in the United States is at the crossroad, and the direction it will take is not at all assured. The postponements, cancellations, and lack of orders for new plants over the past three years raise some serious questions about the future. The present problems of nuclear energy are primarily nontechnical in nature. If the nontechnical issues can be resolved, the future for nuclear looks bright indeed. The LWR and other converters could provide strong competition for coal and other electric power options for a half century or more. If development goals are met, the nuclear breeder offers the prospect of a very large supply of energy at stabilized prices over a time span of centuries

  20. Outlook for nuclear fission energy

    International Nuclear Information System (INIS)

    The electric utility industry has made a substantial commitment to nuclear power. The industrial capability to produce nuclear plants is large and well established. Nevertheless, nuclear energy in the United States is at the crossroad, and the direction it will take is not at all assured. The postponements, cancellations, and lack of orders for new plants over the past three years raise some serious questions about the future. The present problems of nuclear energy are primarily nontechnical in nature. If the nontechnical issues can be resolved, the future for nuclear looks bright indeed. The LWR and other converters could provide strong competition for coal and other electric power options for a half century or more. If development goals are met, the nuclear breeder offers the prospect of a very large supply of energy at stabilized prices over a time span of centuries

  1. Dynamic effect analysis in 240Pu fission at low energy

    International Nuclear Information System (INIS)

    Patin, Y.; Lachkar, J.; Sigaud, J.

    1975-01-01

    The variations of kinetic and excitation energies and fragment masses have been analyzed as a function of the fissioning nucleus excitation energy. Most interest has been taken in the fission of 240 Pu where many experimental data have been reported. The results tend, in the whole, to illustrate the existence of two modes of fission; the first one is superfluid, the other is strongly damped in the last stage of the fission process [fr

  2. Fusion-fission energy systems evaluation

    International Nuclear Information System (INIS)

    Teofilo, V.L.; Aase, D.T.; Bickford, W.E.

    1980-01-01

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept

  3. Fusion-fission energy systems evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Teofilo, V.L.; Aase, D.T.; Bickford, W.E.

    1980-01-01

    This report serves as the basis for comparing the fusion-fission (hybrid) energy system concept with other advanced technology fissile fuel breeding concepts evaluated in the Nonproliferation Alternative Systems Assessment Program (NASAP). As such, much of the information and data provided herein is in a form that meets the NASAP data requirements. Since the hybrid concept has not been studied as extensively as many of the other fission concepts being examined in NASAP, the provided data and information are sparse relative to these more developed concepts. Nevertheless, this report is intended to provide a perspective on hybrids and to summarize the findings of the rather limited analyses made to date on this concept.

  4. The impact of intermediate structure on the average fission cross sections

    International Nuclear Information System (INIS)

    Bouland, O.; Lynn, J.E.; Talou, P.

    2014-01-01

    This paper discusses two common approximations used to calculate average fission cross sections over the compound energy range: the disregard of the W II factor and the Porter-Thomas hypothesis made on the double barrier fission width distribution. By reference to a Monte Carlo-type calculation of formal R-matrix fission widths, this work estimates an overall error ranging from 12% to 20% on the fission cross section in the case of the 239 Pu fissile isotope in the energy domain from 1 to 100 keV with very significant impact on the competing capture cross section. This work is part of a recent and very comprehensive formal R-matrix study over the Pu isotope series and is able to give some hints for significant accuracy improvements in the treatment of the fission channel. (authors)

  5. Bimodal nature in low-energy fission of light actinides

    International Nuclear Information System (INIS)

    Nagame, Yuichiro; Nishinaka, Ichiro; Tsukada, Kazuaki; Ikezoe, Hiroshi; Otsuki, Tsutomu; Sueki, Keisuke; Nakahara, Hiromichi; Kudo, Hisaaki.

    1995-01-01

    To solve various problems in the mass division process of light actinoids, some experiments on the basis of bimodal fission were carried. Mass and kinetic energy distribution of Th-232 and U-238 were determined. Pa-225 (N= 134) and Pa-227 (N=136), fission nuclei, were produced by Bi-209 + 0-16 and Bi-209 + 0-18 heavy ion nucleus reactions, and the mass yield distribution were determined by the time-of-flight method and the radiochemical procedure. From the results, two independent deforming processes were proved in the fission process of light actinoid nuclei. On the deforming process through the low fission barrier, nucleus fissioned after small deformation under the influence of stabilization of the shell structure of fission product. In the case of process through the high barrier, however, the nucleus fissioned after large deformation. The unsymmetrical mass division was derived from the former and the symmetrical one from the latter. (S.Y.)

  6. Generalized Energy-Dependent Q Values for Fission

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, R

    2010-03-31

    We extend Madland's parameterization of the energy release in fission to obtain the dependence of the fission Q value for major and minor actinides on the incident neutron energies in the range 0 {le} E{sub n} {le} 20 MeV. Our parameterization is based on the actinide evaluations recommended for the ENDF/B-VII.1 release. This paper describes the calculation of energydependent fission Q values based on the calculation of the prompt energy release in fission by Madland. This calculation was adopted for use in the LLNL ENDL database and then generalized to obtain the prompt fission energy release for all actinides. Here the calculation is further generalized to the total energy release in fission. There are several stages in a fission event, depending on the time scale. Neutrons and gammas may be emitted at any time during the fission event.While our discussion here is focussed on compound nucleus creation by an incident neutron, similar parameterizations could be obtained for incident gammas or spontaneous fission.

  7. Monte Carlo calculations for intermediate-energy standard neutron field

    International Nuclear Information System (INIS)

    Joneja, O.P.; Subbukutty, K.; Iyengar, S.B.D.; Navalkar, M.P.

    Intermediate-Energy Standard Neutron Field (ISNF) which produces a well characterised spectrum in the energy range of interest for fast reactors including breeders, has been set up at NBS using thin enriched 235 U fission sources. A proposal has been made for setting up a similar facility at BARC using however, easily available natural U instead of enriched U sources, to start with. In order to simulate the neutronics of such a facility Monte Carlo method of calculations has been adopted and developed. The results of these calculations have been compared with those of NBS and it is found that there may be a maximum difference of 10% in spectrum characteristics for the two cases of using thick and thin fission sources. (K.B.)

  8. Study on fission blanket fuel cycling of a fusion-fission hybrid energy generation system

    International Nuclear Information System (INIS)

    Zhou, Z.; Yang, Y.; Xu, H.

    2011-01-01

    This paper presents a preliminary study on neutron physics characteristics of a light water cooled fission blanket for a new type subcritical fusion-fission hybrid reactor aiming at electric power generation with low technical limits of fission fuel. The major objective is to study the fission fuel cycling performance in the blanket, which may possess significant impacts on the feasibility of the new concept of fusion-fission hybrid reactor with a high energy gain (M) and tritium breeding ratio (TBR). The COUPLE2 code developed by the Institute of Nuclear and New Energy Technology of Tsinghua University is employed to simulate the neutronic behaviour in the blanket. COUPLE2 combines the particle transport code MCNPX with the fuel depletion code ORIGEN2. The code calculation results show that soft neutron spectrum can yield M > 20 while maintaining TBR >1.15 and the conversion ratio of fissile materials CR > 1 in a reasonably long refuelling cycle (>five years). The preliminary results also indicate that it is rather promising to design a high-performance light water cooled fission blanket of fusion-fission hybrid reactor for electric power generation by directly loading natural or depleted uranium if an ITER-scale tokamak fusion neutron source is achievable.

  9. Fusion--fission energy systems, some utility perspectives

    International Nuclear Information System (INIS)

    Huse, R.A.; Burger, J.M.; Lotker, M.

    1974-01-01

    Some of the issues that are important in assessing fusion-- fission energy systems from a utility perspective are discussed. A number of qualitative systems-oriented observations are given along with some economic quantification of the benefits from fusion--fission hybrids and their allowed capital cost. (U.S.)

  10. The Future of Energy from Nuclear Fission

    International Nuclear Information System (INIS)

    Kim, Son H.; Taiwo, Temitope

    2013-01-01

    Nuclear energy is an important part of our current global energy system, and contributes to supplying the significant demand for electricity for many nations around the world. There are 433 commercial nuclear power reactors operating in 30 countries with an installed capacity of 367 GWe as of October 2011 (IAEA PRIS, 2011). Nuclear electricity generation totaled 2630 TWh in 2010 representing 14% the world's electricity generation. The top five countries of total installed nuclear capacity are the US, France, Japan, Russia and South Korea at 102, 63, 45, 24, and 21 GWe, respectively (WNA, 2012a). The nuclear capacity of these five countries represents more than half, 68%, of the total global nuclear capacity. The role of nuclear power in the global energy system today has been motivated by several factors including the growing demand for electric power, the regional availability of fossil resources and energy security concerns, and the relative competitiveness of nuclear power as a source of base-load electricity. There is additional motivation for the use of nuclear power because it does not produce greenhouse gas (GHG) emissions or local air pollutants during its operation and contributes to low levels of emissions throughout the lifecycle of the nuclear energy system (Beerten, J. et. al., 2009). Energy from nuclear fission primarily in the form of electric power and potentially as a source of industrial heat could play a greater role for meeting the long-term growing demand for energy worldwide while addressing the concern for climate change from rising GHG emissions. However, the nature of nuclear fission as a tremendously compact and dense form of energy production with associated high concentrations of radioactive materials has particular and unique challenges as well as benefits. These challenges include not only the safety and cost of nuclear reactors, but proliferation concerns, safeguard and storage of nuclear materials associated with nuclear fuel cycles

  11. Experiments in intermediate energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Dehnhard, D.

    2003-02-28

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers.

  12. Nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1991-01-01

    The theme that unites the sometimes seemingly disparate experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in their radiative decays in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of our BNL experiments E810, E854, as well as our approved experiment at RHIC), -- all these projects share this common goal. Our other experiments represent different approaches to the same broad undertaking. LAMPF E1097 will provide definitive answers to the question of the spin dependence of the inelastic channel of pion production in the n-p interaction. FNAL E683 may well open a new field of investigation in nuclear physics: that of just how quarks and gluons interact with nuclear matter as they transverse nuclei of different sizes. In most all of the experiments mentioned above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are unavailable to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do

  13. Nuclear structure at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Bonner, B.E.; Mutchler, G.S.

    1991-09-30

    The theme that unites the sometimes seemingly disparate experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in their radiative decays in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of our BNL experiments E810, E854, as well as our approved experiment at RHIC), -- all these projects share this common goal. Our other experiments represent different approaches to the same broad undertaking. LAMPF E1097 will provide definitive answers to the question of the spin dependence of the inelastic channel of pion production in the n-p interaction. FNAL E683 may well open a new field of investigation in nuclear physics: that of just how quarks and gluons interact with nuclear matter as they transverse nuclei of different sizes. In most all of the experiments mentioned above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are unavailable to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do.

  14. Considerations for a sustainable nuclear fission energy in Europe

    International Nuclear Information System (INIS)

    Cognet, G.; Ledermann, P.; Cacuci, D.

    2005-01-01

    Presented is the global energy perspectives and and sustainable development fission vision scenario. Described are the innovative concepts with technological breakthroughs concerning the fuel cycle and evolution of the spent fuel radiotoxic contents

  15. Role of Multichance Fission in the Description of Fission-Fragment Mass Distributions at High Energies

    Science.gov (United States)

    Hirose, K.; Nishio, K.; Tanaka, S.; Léguillon, R.; Makii, H.; Nishinaka, I.; Orlandi, R.; Tsukada, K.; Smallcombe, J.; Vermeulen, M. J.; Chiba, S.; Aritomo, Y.; Ohtsuki, T.; Nakano, K.; Araki, S.; Watanabe, Y.; Tatsuzawa, R.; Takaki, N.; Tamura, N.; Goto, S.; Tsekhanovich, I.; Andreyev, A. N.

    2017-12-01

    Fission-fragment mass distributions were measured for U 237 - 240 , Np 239 - 242 , and Pu 241 - 244 populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels in the reaction O 18 +U 238 at the Japan Atomic Energy Agency tandem facility. Among them, the data for U 240 and Np 240 ,241 ,242 were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multichance fission.

  16. Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

    Science.gov (United States)

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

    2018-03-01

    The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

  17. Investigation of the heavy nuclei fission with anomalously high values of the fission fragments total kinetic energy

    Science.gov (United States)

    Khryachkov, Vitaly; Goverdovskii, Andrei; Ketlerov, Vladimir; Mitrofanov, Vecheslav; Sergachev, Alexei

    2018-03-01

    Binary fission of 232Th and 238U induced by fast neutrons were under intent investigation in the IPPE during recent years. These measurements were performed with a twin ionization chamber with Frisch grids. Signals from the detector were digitized for further processing with a specially developed software. It results in information of kinetic energies, masses, directions and Bragg curves of registered fission fragments. Total statistics of a few million fission events were collected during each experiment. It was discovered that for several combinations of fission fragment masses their total kinetic energy was very close to total free energy of the fissioning system. The probability of such fission events for the fast neutron induced fission was found to be much higher than for spontaneous fission of 252Cf and thermal neutron induced fission of 235U. For experiments with 238U target the energy of incident neutrons were 5 MeV and 6.5 MeV. Close analysis of dependence of fission fragment distribution on compound nucleus excitation energy gave us some explanation of the phenomenon. It could be a process in highly excited compound nucleus which leads the fissioning system from the scission point into the fusion valley with high probability.

  18. Investigation of the heavy nuclei fission with anomalously high values of the fission fragments total kinetic energy

    Directory of Open Access Journals (Sweden)

    Khryachkov Vitaly

    2018-01-01

    Full Text Available Binary fission of 232Th and 238U induced by fast neutrons were under intent investigation in the IPPE during recent years. These measurements were performed with a twin ionization chamber with Frisch grids. Signals from the detector were digitized for further processing with a specially developed software. It results in information of kinetic energies, masses, directions and Bragg curves of registered fission fragments. Total statistics of a few million fission events were collected during each experiment. It was discovered that for several combinations of fission fragment masses their total kinetic energy was very close to total free energy of the fissioning system. The probability of such fission events for the fast neutron induced fission was found to be much higher than for spontaneous fission of 252Cf and thermal neutron induced fission of 235U. For experiments with 238U target the energy of incident neutrons were 5 MeV and 6.5 MeV. Close analysis of dependence of fission fragment distribution on compound nucleus excitation energy gave us some explanation of the phenomenon. It could be a process in highly excited compound nucleus which leads the fissioning system from the scission point into the fusion valley with high probability.

  19. Results of fission product release from intermediate-scale MCCI [molten core-concrete interaction] tests

    International Nuclear Information System (INIS)

    Spencer, B.W.; Thompson, D.H.; Fink, J.K.; Gunther, W.H.; Sehgal, B.R.

    1988-01-01

    A program of reactor-material molten core-concrete interaction (MCCI) tests and related analyses are under way at Argonne National Laboratory under sponsorship of the Electric Power Research Institute (EPRI). The particular objective of these tests is to provide data pertaining to the release of nonvolatile fission products such as La, Ba, and Sr, plus other aerosol materials, from the coupled thermal-hydraulic and chemical processes of the MCCI. The first stages of the program involving small and intermediate-scale tests have been completed. Three small-scale tests (/approximately/5 kg corium) and nine intermediate-scale tests (/approximately/30 kg corium) were performed between September 1985 and September 1987. Real reactor materials were used in these tests. Sustained internal heat generation at nominally 1 kW per kg of melt was provided by direct electrical heating of the corium mixture. MCCI tests were performed with both fully and partially oxidized corium mixtures that contained a variety of nonradioactive materials such as La 2 O 3 , BaO, and SrO to represent fission products. Both limestone/common sand and basaltic concrete basemats were used. The system was instrumented for characterization of the thermal hydraulic, chemical, gas release, and aerosol release processes

  20. Preliminary fission product energy release measurements for thermal neutron fission of 235U

    International Nuclear Information System (INIS)

    Dickens, J.K.; Love, T.A.; McConnell, J.W.; Emery, J.F.; Peelle, R.W.

    1976-03-01

    An experimental system to measure time-dependent spectra of β and γ rays from fission-product production by thermal neutron fission of 235 U is described, and for each component (β and γ) the system has been tested with a pilot data-accumulation run. Data reduction techniques are described and test results given. Gamma-ray spectra are compared with calculations using ENDF/B-IV data files. Both β- and γ-ray spectra were integrated to give total yields and total energy-release results for times after fission between 3 and 14400 sec. These preliminary integral data are compared with previous measurements and with integral calculations using ENDF/B-IV data files

  1. Prediction of fission barrier height for induced fission reactions with 16O at several energies

    Directory of Open Access Journals (Sweden)

    S Soheyli

    2009-09-01

    Full Text Available We have calculated the fission barrier height for 16O+208Pb, 16O+209Bi, 16O+232Th, 16O+238U and 16O+248Cm systems in energy range between 90 MeV to 215 MeV. This method is based on the experimental data for angular anisotropies of fission fragments. In present work, we have used the transition state model (STM for two different cases: the first case is without neutron emission correction and the second case is with neutron emission correction. In this paper, we have predicted the fission barrier for the two super heavy nuclei that were not reported previously with experimental methods.

  2. Measurement of energy dependence of fission fragment angular anisotropy for resonance neutron induced fission of 235U aligned target

    International Nuclear Information System (INIS)

    Bogdzel, A.A.; Furman, W.I.

    1996-01-01

    The results of the experiment on measuring the energy dependence of fission fragment angular anisotropy in resonance neutron induced fission of 235 U aligned target in energy region up to 42 eV are presented. The agreement with the data of Pattenden and Postma in resonances is good enough, while the theoretical curve, calculated using the R-matrix multilevel two fission channel approach, does not seem to describe the energy dependence of fission fragment angular anisotropy property. The necessity of taking into account the interference between levels with different spins is discussed. 11 refs., 2 figs

  3. Proton-induced fission at ultra sub-barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Back, B.B.; Betts, R.R.; Fernandez, P.B.; Gehring, J.C.; Henderson, D.J.; Nagame, Y.

    1991-01-01

    Cross sections for proton-induced fission of {sup 238}U have been measured at seven proton energies ranging from 3.0 to 4.45 MeV using two position sensitive parallel-grid avalanche counters in a kinematic coincidence. In addition, an upper limit for the fission cross section was established at extreme sub-barrier energies down to a level of {approx equal}20 pb at 3 MeV. This result is in contradiction to recent findings of Ajitanand et al., who found that the fission excitation function exhibited a plateaux at about 1000 pb in the energy range from 1.0 to 3.5 MeV. 7 refs., 3 figs., 1 tab.

  4. Perspective on the fusion-fission energy concept

    International Nuclear Information System (INIS)

    Liikala, R.C.; Perry, R.T.; Teofilo, V.L.

    1978-01-01

    A concept which has potential for near-term application in the electric power sector of our energy economy is combining fusion and fission technology. The fusion-fission system, called a hybrid, is distinguished from its pure fusion counterpart by incorporation of fertile materials (uranium or thorium) in the blanket region of a fusion machine. The neutrons produced by the fusion process can be used to generate energy through fission events in the blanket or produce fuel for fission reactors through capture events in the fertile material. The performance requirements of the fusion component of hybrids is perceived as being less stringent than those for pure fusion electric power plants. The performance requirements for the fission component of hybrids is perceived as having been demonstrated or could be demonstrated with a modest investment of research and development funds. This paper presents our insights and observations of this concept in the context of why and where it might fit into the picture of meeting our future energy needs. A bibliography of hybrid research is given

  5. Nuclear photoreactions at intermediate energies

    International Nuclear Information System (INIS)

    Christillin, P.

    1989-02-01

    We review the interaction of real photons with nuclei up to the GeV region. The common microscopic description of exchange effects below threshold and of the corresponding real photoproduction above, is emphasized. The theoretical problems connected with π photoproduction in Δ region and vector meson photoproduction are spelled out and solved. The gross features of the reaction mechanism are shown to explain both the low energy region, the bulk properties around the Δ resonance as well as the appearance of shadowing only above ρ threshold

  6. Intermediate-energy light sources

    CERN Document Server

    Corbett, W

    2003-01-01

    Increasingly, atomic scale information underlies scientific and technological progress in disciplines ranging from pharmaceutical development to materials synthesis to environmental remediation. While a variety of research tools are used to provide atomic scale information, synchrotron radiation has proved invaluable in this quest. The rapid growth of soft- and hard X-ray synchrotron light sources stands as stark testimony to the importance and utility of synchrotron radiation. Starting from just a handful of synchrotron light sources in the early 1970s, this burgeoning field now includes over 70 proposed, in-construction, or operating facilities in 23 countries on five continents. Along the way, synchrotron light facilities have evolved from small laboratories extracting light parasitically from storage rings designed for high-energy physics research to large, dedicated sources using the latest technology to produce extraordinarily bright photon beams. The basic layout of a multi-GeV storage ring light sourc...

  7. Neutron emission and fragment yield in high-energy fission

    International Nuclear Information System (INIS)

    Grudzevich, O. T.; Klinov, D. A.

    2013-01-01

    The KRIS special library of spectra and emission probabilities in the decays of 1500 nuclei excited up to energies between 150 and 250 MeV was developed for correctly taking into account the decay of highly excited nuclei appearing as fission fragments. The emission of neutrons, protons, and photons was taken into account. Neutron emission fromprimary fragments was found to have a substantial effect on the formation of yields of postneutron nuclei. The library was tested by comparing the calculated and measured yields of products originating from the fission of nuclei that was induced by high-energy protons. The method for calculating these yields was tested on the basis of experimental data on the thermal-neutroninduced fission of 235 U nuclei

  8. Intermediate-energy nuclear chemistry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

  9. Intermediate-energy nuclear chemistry workshop

    International Nuclear Information System (INIS)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities

  10. Role of energy cost in the yield of cold ternary fission of Cf

    Indian Academy of Sciences (India)

    Abstract. The energy costs in the cold ternary fission of 252Cf for various light charged particle emission are calculated by including Wong's correction for Coulomb potential. Energy cost is found to be higher in cold fission than in normal fission. It is found that energy cost always increases with decrease in experimental yield ...

  11. Determination of shell energies. Nuclear deformations and fission barriers

    International Nuclear Information System (INIS)

    Koura, Hiroyuki; Tachibana, Takahiro; Uno, Masahiro; Yamada, Masami.

    1996-01-01

    We have been studying a method of determining nuclear shell energies and incorporating them into a mass formula. The main feature of this method lies in estimating shell energies of deformed nuclei from spherical shell energies. We adopt three assumptions, from which the shell energy of a deformed nucleus is deduced to be a weighted sum of spherical shell energies of its neighboring nuclei. This shell energy should be called intrinsic shell energy since the average deformation energy also acts as an effective shell energy. The ground-state shell energy of a deformed nucleus and its equilibrium shape can be obtained by minimizing the sum of these two energies with respect to variation of deformation parameters. In addition, we investigate the existence of fission isomers for heavy nuclei with use of the obtained shell energies. (author)

  12. High energy γ rays from 252Cf spontaneous fission

    Science.gov (United States)

    Hofman, D. J.; Back, B. B.; Montoya, C. P.; Schadmand, S.; Varma, R.; Paul, P.

    1993-03-01

    The spontaneous fission decay of 252Cf has been analyzed in a statistical model with emphasis on describing recently reported high energy γ-ray spectra. An enhanced γ emission in the range from 3 to 10 MeV which is observed for nearly symmetric mass splits is readily understood as a result of the different fragment excitation energies. The model includes a viscous motion to the scission point with the possibility of prescission γ emission. It was found that even with saddle-to-scission times of τscneutron multiplicities, prescission γ rays are overwhelmed by fragment γ rays. Thus, the recently reported strong angular anisotropy of γ rays in the range Eγ=8-12 MeV is unexplained within the present understanding of the fission process.

  13. 5He, 7He and 8Li (E=2.26 MeV) intermediate ternary particles in the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    Kopatch, Yu. N.; Goennenwein, F.

    2002-02-01

    The neutron-unstable odd-N isotopes 5 He, 7 He and 8 Li (in its excited state of E * = 2.26 MeV) were measured to show up as short-lived intermediate light-charged-particles (LCP) in ternary fission of 252 Cf. For the study a high-efficiency angular correlation measurement between neutrons, LCPs and main fission fragments has been performed. The evidence for the ternary 5 He and 7 He particles (lifetimes: 1 x 10 -21 s, and 4 x 10 -21 s, respectively) was disclosed from the measured angular distributions of their decay neutrons focused by the emission in flight towards the direction of motion of 4 He and 6 He ternary particles. Similarly, neutrons observed to be peaked around Li-particle motion could be attributed to the decay of the second excited state at E * = 2.26 MeV (lifetime: 2 x 10 -20 s) of 8 Li. The fractional yields of the intermediate 5 He and 7 He ternary fission modes relative to the ''true'' ternary 4 He and 6 He modes, respectively, were determined to be 0.21(5) for both cases. The mean energy of the 4 He residues resulting from the 5 He decay was determined to be 12.4(3) MeV, compared to 15.7(2) MeV for all ternary α-particles registered, and to 16.4(3) MeV for the true ternary α-particles. The mean energy of the 6 He residues from the 7 He decay is 11.0(15) MeV, compared to 12.3(5) MeV for all ternary 6 He particles. The population of 8 Li * was deduced to be 0.06(2) relative to Li ternary fission, and 0.33(20) relative to the yield of particle stable 8 Li. The perspective of using the observed intermediate LCPs for probing the ternary scission configuration in 252 Cf fission with the aid of trajectory calculations is briefly discussed. (orig.)

  14. Intermediate Energy Activation File (IEAF-99)

    International Nuclear Information System (INIS)

    Korovin, Yu.; Konobeev, A.; Pereslavtsev, P.; Stankovskij, A.; Fischer, U.; Moellendorff, U. von

    1999-01-01

    Nuclear data library IEAF-99, elaborated to study processes of interactions of intermediate energy neutrons with materials in accelerator driven systems, is described. The library is intended for activation and transmutation studies for materials irradiated by neutrons. IEAF-99 contains evaluated neutron induced reaction cross sections at the energies 0-150 MeV for 665 stable and unstable nuclei from C to Po. Approximately 50,000 excitation functions are included in the library. The IEAF-99 data are written in the ENDF-6 format combining MF = 3,6 MT = 5 data recording. (author)

  15. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 2: Power from nuclear fission

    Science.gov (United States)

    Clement, J. D.

    1973-01-01

    Different types of nuclear fission reactors and fissionable materials are compared. Special emphasis is placed upon the environmental impact of such reactors. Graphs and charts comparing reactor facilities in the U. S. are presented.

  16. Dynamical effects and time scale in fission processes in nuclear collisions in the fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.; Bellaize, N.; Bougault, R.; Brou, R.; Cussol, D.; Durand, D.; Genouin-Duhamel, E.; Lecolley, J.F.; Le Neindre, N.; Lopez, O.; Nguyen, A.D.; Peter, J.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Brun, C. le; Genoux-Lubain, A.

    1999-01-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn... o btained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distributions of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mid-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, authors observed two components: The first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, authors present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component authors extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component authors propose a scenario to explain such process and authors discuss the physical parameters which can be extracted

  17. Dynamical effects and time scale in fission processes in nuclear collisions in the Fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.

    1999-10-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn...) obtained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distribution of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mi-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, we observed two components: the first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, we present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component we extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component we propose a scenario to explain such process and we discuss the physical parameters which can be extracted. (authors)

  18. Characteristic relation for the mass and energy distribution of the nuclear fission products

    International Nuclear Information System (INIS)

    Alexandru, G.

    1977-01-01

    The dispersion relation for nuclear fission is written in the two part fragmentation approach which allows to obtain the characteristic relation for the mass and energy distribution of the nuclear fission products. One explains the resonance approximation in the mass distribution of the fission products taking into account the high order resonances too. (author)

  19. The Power Makers' Challenge And the Need for Fission Energy

    CERN Document Server

    Nicholson, Martin

    2012-01-01

    The Power Makers - the producers of our electricity - must meet the demands of their customers while also addressing the threat of climate change. There are widely differing views about solutions to electricity generation in an emission constrained world. Some see the problem as relatively straight forward, requiring deep cuts in emissions now by improving energy efficiency, energy conservation and using only renewable resources. Many electricity industry engineers and scientists see the problem as being much more involved.   The Power Makers ’ Challenge: and the need for Fission Energy looks at why using only conventional renewable energy sources is not quite as simple as it seems. Following a general introduction to electricity and its distribution, the author quantifies the reductions needed in greenhouse gas emissions from the power sector in the face of ever increasing world demands for electricity. It provides some much needed background on the many energy sources available for producing electricity ...

  20. Theoretical model application to the evaluation of fission neutron data up to 20 MeV incidence energy

    International Nuclear Information System (INIS)

    Ruben, A.; Maerten, H.; Seeliger, D.

    1990-01-01

    A complex statistical theory of fission neutron emission combined with a phenomenological fission model has been used to calculate fission neutron data for 238 U. Obtained neutron multiplicities and energy spectra as well as average fragment energies for incidence energies from threshold to 20 MeV (including multiple-chance fission) are compared with traditional data representations. (author). 19 refs, 6 figs

  1. Proceedings of the Second Fusion-Fission Energy Systems Review Meeting

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-11-02

    The agenda of the meeting was developed to address, in turn, the following major areas: specific problem areas in nuclear energy systems for application of fusion-fission concepts; current and proposed fusion-fission programs in response to the identified problem areas; target costs and projected benefits associated with fusion-fission energy systems; and technical problems associated with the development of fusion-fission concepts. The greatest emphasis was placed on the characteristics of and problems, associated with fuel producing fusion-fission hybrid reactors.

  2. q-Gamow states for intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Plastino, A. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Rocca, M.C., E-mail: mariocarlosrocca@gmail.com [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Ferri, G.L. [Fac. de C. Exactas, National University La Pampa, Peru y Uruguay, Santa Rosa, La Pampa (Argentina); Zamora, D.J. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina)

    2016-11-15

    In a recent paper Plastino and Rocca (2016) [18] we have demonstrated the possible existence of Tsallis' q-Gamow states. Now, accelerators' experimental evidence for Tsallis' distributions has been ascertained only at very high energies. Here, instead, we develop a different set of q-Gamow states for which the associated q-Breit–Wigner distribution could easily be found at intermediate energies, for which accelerators are available at many locations. In this context, it should be strongly emphasized Vignat and Plastino (2009) [2] that, empirically, one never exactly and unambiguously “detects” pure Gaussians, but rather q-Gaussians. A prediction is made via Eq. (3.4).

  3. Electron scattering from sodium at intermediate energies

    International Nuclear Information System (INIS)

    Mitroy, J.; McCarthy, I.E.

    1986-10-01

    A comprehensive comparison is made between theoretical calculations and experimental data for intermediate energy (≥ 10 eV) electron scattering from sodium vapour. The theoretical predictions of coupled-channels calculations (including one, two or four channels) do not agree with experimental values of the differential cross sections for elastic scattering or the resonant 3s to 3p excitation. Increasingly-more-sophisticated calculations, incorporating electron correlations in the target states, and also including core-excited states in the close-coupling expansion, are done at a few selected energies in an attempt to isolate the cause of the discrepancies between theory and experiment. It is found that these more-sophisticated calculations give essentially the same results as the two- and four-channel calculations using Hartree-Fock wavefunctions. Comparison of the sodium high-energy elastic differential cross sections with those of neon suggests that the sodium differential cross section experiments may suffer from systematic errors. There is also disagreement, at the higher energies, between theoretical values for the scattering parameters and those that are derived from laser-excited superelastic scattering and electron photon coincidence experiments. When allowance is made for the finite acceptance angle of the electron spectrometers used in the experiments by convoluting the theory with a function representing the distribution of electrons entering the electron spectrometer it is found that the magnitudes of the differences between theory and experiment are reduced

  4. Dynamical aspects of intermediate-energy heavy-ion collisons

    Science.gov (United States)

    Dempsey, James Francis

    1997-10-01

    The production of neutrons, light charged particles (LCPs), and intermediate-mass fragments (IMFs), from the four reactions 55 MeV/A [124,136Xe] + [112,124Sn], is studied with an experimental apparatus which is highly efficient for the detection of both charged particles and neutrons. The IMFs are found more localized in the mid-velocity region (parallel velocity close to center of mass) than are the LPCs, and the detected multiplicity of IMFs depends linearly on the charge lost from the projectile. IMF multiplicity is found to be largely independent of the neutron excess of the system, aside from a slight increase with increasing neutron excess that is expected from statistical-model simulations. Remnants of the projectile, with very little velocity reduction, are found for most of the reaction cross section. Isotopic and isobaric fragment yields in the projectile-velocity region indicate that charge-to- mass ratio neutralization is generally not achieved but is approached when little remains of the projectile. For all systems, the fragments found in the mid-velocity region are substantially more neutron rich than those found in the velocity region dominated by the emission from the projectile. This observation can be qualitatively accounted for if the mid-velocity source (or sources) is either more neutron rich or smaller, with the same neutron-to-proton ratio, than the source with the velocity of the projectile. The observations of this work suggest that the intermediate mass fragments are, to a large extent, formed dynamically by a multiple neck rupture or a proximity-fission type mechanism. Though it remains unexplained, this process enhances the neutron- to-proton ratio of the emitted fragments. This scenario is reminiscent of low-energy ternary fission and one predicted by Boltzmann-Uehling-Uhlenbeck (BUU) calculations. However, these calculations predict too much velocity damping of the projectile remnant and do not produce a mid-velocity neutron

  5. Economic implications of fusion-fission energy systems

    International Nuclear Information System (INIS)

    Deonigi, D.E.; Schulte, S.C.

    1979-04-01

    The principal conclusions that can be made based on the estimated costs reported in this paper are twofold. First, hybrid reactors operating symbiotically with conventional fission reactors are a potentially attractive supply alternative. Estimated hybrid energy system costs are slightly greater than estimated costs of the most attractive alternatives. However, given the technological, economic, and institutional uncertainties associated with future energy supply, differences of such magnitude are of little significance. Second, to be economically viable, hybrid reactors must be both fuel producers and electricity producers. A data point representing each hybrid reactor driver-blanket concept is plotted as a function of net electrical production efficiency and annual fuel production. The plots illustrate that the most economically viable reactor concepts are those that produce both fuel and electricity

  6. Sustainable, Full-Scope Nuclear Fission Energy at Planetary Scale

    Directory of Open Access Journals (Sweden)

    Robert Petroski

    2012-11-01

    Full Text Available A nuclear fission-based energy system is described that is capable of supplying the energy needs of all of human civilization for a full range of human energy use scenarios, including both very high rates of energy use and strikingly-large amounts of total energy-utilized. To achieve such “planetary scale sustainability”, this nuclear energy system integrates three nascent technologies: uranium extraction from seawater, manifestly safe breeder reactors, and deep borehole disposal of nuclear waste. In addition to these technological components, it also possesses the sociopolitical quality of manifest safety, which involves engineering to a very high degree of safety in a straightforward manner, while concurrently making the safety characteristics of the resulting nuclear systems continually manifest to society as a whole. Near-term aspects of this nuclear system are outlined, and representative parameters given for a system of global scale capable of supplying energy to a planetary population of 10 billion people at a per capita level enjoyed by contemporary Americans, i.e., of a type which might be seen a half-century hence. In addition to being sustainable from a resource standpoint, the described nuclear system is also sustainable with respect to environmental and human health impacts, including those resulting from severe accidents.

  7. Energy dissipation in the process of ternary fission in heavy nuclear reaction

    International Nuclear Information System (INIS)

    Li Xian; Wang Chengqian; Yan Shiwei

    2015-01-01

    We studied the evolution of the collective motion, interaction potential, the total kinetic and excitation energies in ternary fissions of 197 Au + 197 Au system at 15 MeV/u, and discussed energy dissipation of this reaction. Through the comparison with energy-angle correlation data in binary fissions, we preliminarily concluded that the rst fission of ternary fission was an extreme deep-inelastic process. We further analyzed the correlation of the total kinetic energy with impact parameters in both binary and ternary reactions, and found that the total energy of binary reactions systems was lost about 150 MeV more than ternary fission with small impact parameters, and with larger impact parameters the total energy of ternary reactions were lost 300 MeV more than binary reactions. (authors)

  8. Fission cross section calculations for 209Bi target nucleus based on fission reaction models in high energy regions

    Directory of Open Access Journals (Sweden)

    Kaplan Abdullah

    2015-01-01

    Full Text Available Implementation of projects of new generation nuclear power plants requires the solving of material science and technological issues in developing of reactor materials. Melts of heavy metals (Pb, Bi and Pb-Bi due to their nuclear and thermophysical properties, are the candidate coolants for fast reactors and accelerator-driven systems (ADS. In this study, α, γ, p, n and 3He induced fission cross section calculations for 209Bi target nucleus at high-energy regions for (α,f, (γ,f, (p,f, (n,f and (3He,f reactions have been investigated using different fission reaction models. Mamdouh Table, Sierk, Rotating Liquid Drop and Fission Path models of theoretical fission barriers of TALYS 1.6 code have been used for the fission cross section calculations. The calculated results have been compared with the experimental data taken from the EXFOR database. TALYS 1.6 Sierk model calculations exhibit generally good agreement with the experimental measurements for all reactions used in this study.

  9. Simultaneous measurement of neutron-induced fission and capture cross sections for 241Am at neutron energies below fission threshold

    Science.gov (United States)

    Hirose, K.; Nishio, K.; Makii, H.; Nishinaka, I.; Ota, S.; Nagayama, T.; Tamura, N.; Goto, S.; Andreyev, A. N.; Vermeulen, M. J.; Gillespie, S.; Barton, C.; Kimura, A.; Harada, H.; Meigo, S.; Chiba, S.; Ohtsuki, T.

    2017-06-01

    Fission and capture reactions were simultaneously measured in the neutron-induced reactions of 241Am at the spallation neutron facility of the Japan Proton Accelerator Research Complex (J-PARC). Data for the neutron energy range of En=0.1-20 eV were taken with the TOF method. The fission events were observed by detecting prompt neutrons accompanied by fission using liquid organic scintillators. The capture reaction was measured by detecting γ rays emitted in the deexcitation of the compound nuclei using the same detectors, where the prompt fission neutrons and capture γ rays were separated by a pulse shape analysis. The cross sections were obtained by normalizing the relative yields at the first resonance to evaluations or other experimental data. The ratio of the fission to capture cross sections at each resonance is compared with those from an evaluated nuclear data library and other experimental data. Some differences were found between the present values and the library/literature values at several resonances.

  10. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Directory of Open Access Journals (Sweden)

    Ramos D.

    2016-01-01

    Isotopic fission yields of 250Cf, 244Cm, 240Pu, 239Np and 238U are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented.

  11. [Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    1989-01-01

    We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. The effort in quantum field theory provides theoretical results to test or replace assumed ingredients of the QCM. By the explicit example of a scalar field theory in 2D we have solved the long-standing problem of how to treat the dynamics of the vacuum in light-front quantization. We now propose to solve the same problem for simple Fermion field theories in 2D such as the Gross-Neveu model. We propose in subsequent years to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We have completed our analysis of the SLAC E101 and E133 experiments on Deuterium to elucidate the degree to which a six-quark cluster contribution is admissable in the Bjorken x > 1 data. We have completed our development of a parameterized thermal liquid drop model for light nuclei. In addition we have completed a set of predictions for the formation of a ''nuclear stratosphere'' in nuclei created by intermediate energy heavy ion interactions. These results motivate a new investigation of the temperature dependence of the ion-ion potential with particular emphasis on the thermal dependence of the barrier height and radius. We have also shown that a consistent treatment of relativistic effects is important for a theoretical description of the elastic magnetic form factor of 17 O. 85 refs

  12. Fission energy program of the U. S. Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-01

    The document describes programs managed by the Program Director for Nuclear Energy, Department of Energy, and under the cognizance of the Committee on Science and Technology, United States House of Representatives. The major portion of the document is concerned with civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977, but it also includes descriptions of the space applications and naval reactor programs.

  13. Fission-product energy release for times following thermal-neutron fission of 235U between 2 and 14000 seconds

    International Nuclear Information System (INIS)

    Dickens, J.K.; Emery, J.F.; Love, T.A.; McConnell, J.W.; Northcutt, K.J.; Peelle, R.W.; Weaver, H.

    1977-10-01

    Fission-product decay energy-releases rates were measured for thermal-neutron fission of 235 U. Samples of mass 1 to 10 μg were irradiated for 1 to 100 sec by use of the fast pneumatic-tube facility at the Oak Ridge Research Reactor. The resulting beta- and gamma-ray emissions were counted for times-after-fission between 2 and 14,000 seconds. The data were obtained for beta and gamma rays separately as spectral distributions, N(E/sub γ/) vs E/sub γ/ and N(E/sub beta/) vs E/sub β/. For the gamma-ray data the spectra were obtained by using a NaI detector, while for the beta-ray data the spectra were obtained by using an NE-110 detector with an anticoincidence mantle. The raw data were unfolded to provide spectral distributions of modest resolution. These were integrated over E/sub γ/ and E/sub β/ to provide total yield and energy integrals as a function of time after fission. Results are low compared to the present 1973 ANS Decay-heat standard. A complete description of the experimental apparatus and data-reduction techniques is presented. The final integral data are given in tabular and graphical form and are compared with published data. 41 figures, 13 tables

  14. Sequential character of low-energy ternary and quaternary nuclear fission

    Science.gov (United States)

    Kadmensky, S. G.; Bulychev, A. O.

    2016-09-01

    An analysis of low-energy true ternary (quaternary) nuclear fission leads to the conclusion that these fission modes have a sequential two-step (three-step) character such that the emission of a third particle (third and fourth particles) and the separation of fission fragments occur at distinctly different instants, in contrast to the simultaneous emergence of all fission products in the case of onestep ternary (quaternary) fission. This conclusion relies on the following arguments. First, the emission of a third particle (third and fourth particles) from a fissile nucleus is due to a nonevaporative mechanism associated with a nonadiabatic character of the collective deformation motion of this nucleus at the stages preceding its scission. Second, the axial symmetry of the deformed fissile compound nucleus and the direction of its symmetry axis both remain unchanged at all stages of ternary (quaternary) fission. This circumstancemakes it possible to explain themechanism of the appearance of observed anisotropies and T — odd asymmeries in the angular distributions of products of ternary (quaternary) nuclear fission. Third, the T —odd asymmetry discovered experimentally in ternary nuclear fission induced by cold polarized neutrons obeys the T —invariance condition only in the case of a sequential two-step (three-step) character of true ternary (quaternary) nuclear fission. At the same time, this asymmetry is not a T —invariant quantity in the case of the simultaneous emission of products of true ternary (quaternary) nuclear fission from the fissile compound nucleus.

  15. Nuclear structure at intermediate energies. Progress report

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1992-01-01

    We report here oil the progress that we made for the nine months beginning October 1, 1991 for DOE Grant No. DE-FG05-87ER40309. The report covers the third year of a three year grant. Since we are submitting an accompanying Grant Renewal Proposal, we provide in this report more background information than usual for the different projects. The theme that unites the experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of AGS bar p experiment E854, AGS heavy ion experiment E810, as-well as the approved STAR experiment at RHIC), - all these projects share this common goal. FNAL E683 may well open a new field of investigation in nuclear physics: That of just how colored quarks and gluons interact with nuclear matter as they traverse nuclei of different-sizes. In most all of the experiments mentioned, above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are available to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do. The format we follow in the Progress Report is,to provide a concise, but fairly complete write-up on each project. The publications listed in Section In give much greater detail on many of the projects. The aim in this report is to focus on the physics goals, the results, and their significance

  16. Fission energy program of the U.S. Department of Energy. FY 1980

    International Nuclear Information System (INIS)

    1979-04-01

    This document presents the baseline implementation program plan as of January 1979 and is derived from the National Energy Plan and other major policy documents. The document discusses civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977 and the National Energy Act of 1978. It derives the fission energy policy and program objectives from the National Energy Plan and Act, describes the overall program strategy, and presents the overall budget. The approach used in managing the program, including the program structure and methods used for program control, is explained. The civilian fission power development implementation programs are described in detail. Other considerations affecting civilian nuclear power development are also discussed

  17. Fission fragment yields and total kinetic energy release in neutron-induced fission of235,238U,and239Pu

    Science.gov (United States)

    Tovesson, F.; Duke, D.; Geppert-Kleinrath, V.; Manning, B.; Mayorov, D.; Mosby, S.; Schmitt, K.

    2018-03-01

    Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.

  18. The fusion-fission and quasi-fission processes in the reaction {sup 48}Ca + {sup 208}Pb at energies near the Coulomb barrier

    Energy Technology Data Exchange (ETDEWEB)

    Prokhorova, E.V. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)], E-mail: elena.prokhorova@jinr.ru; Bogachev, A.A.; Itkis, M.G.; Itkis, I.M.; Knyazheva, G.N.; Kondratiev, N.A.; Kozulin, E.M.; Krupa, L.; Oganessian, Yu.Ts.; Pokrovsky, I.V. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Pashkevich, V.V. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Rusanov, A.Ya. [Institute of Nuclear Physics of the National Nuclear Center of Kazakhstan, 480082 Alma-Ata (Kazakhstan)

    2008-04-01

    Mass-energy distributions (MEDs) and capture-fission cross sections have been measured in the reaction {sup 48}Ca + {sup 208}Pb {yields}{sup 256}No at the energies E{sub lab}=206-242 MeV using a double-arm time-of-flight spectrometer CORSET. It has been observed that MED of the fragments consists of two parts, namely, the classical fusion-fission process corresponding to the symmetric fission of {sup 256}No and quasi-fission 'shoulders' corresponding to the light fragment masses {approx}60-90 u and complimentary heavy fragment masses. The quasi-fission 'shoulders' have a higher total kinetic energy (TKE) as compared with that expected for the classical fission. A mathematical formalism was employed for the MEDs fragment decomposition into fusion-fission and quasi-fission components. In the fusion-fission process a high-energy Super-Short mode has been discovered for the masses M{sub H}=130-135 u and the TKE of {approx}233 MeV.

  19. Inverse kinematics technique for the study of fission-fragment isotopic yields at GANIL energies

    International Nuclear Information System (INIS)

    Delaune, O.

    2012-01-01

    The characteristics of the fission-products distributions result of dynamical and quantum properties of the deformation process of the fissioning nucleus. These distributions have also an interest for the conception of new nuclear power plants or for the transmutation of the nuclear wastes. Up to now, our understanding of the nuclear fission remains restricted because of experimental limitations. In particular, yields of the heavy fission products are difficult to get with precision. In this work, an innovative experimental technique is presented. It is based on the use of inverse kinematics coupled to the use of a spectrometer, in which a 238 U beam at 6 or 24 A MeV impinges on light targets. Several actinides, from 238 U to 250 Cf, are produced by transfer or fusion reactions, with an excitation energy ranges from ten to few hundreds MeV depending on the reaction and the beam energy. The fission fragments of these actinides are detected by the VAMOS spectrometer or the LISE separator. The isotopic yields of fission products are completely measured for different fissioning systems. The neutron excess of the fragments is used to characterise the isotopic distributions. Its evolution with excitation energy gives important insights on the mechanisms of the compound-nucleus formation and its deexcitation. Neutron excess is also used to determine the multiplicity of neutrons evaporated by the fragments. The role of the proton and neutron shell effects into the formation of fission fragments is also discussed. (author) [fr

  20. Nuclear energy: fusion and fission - From the atomic nucleus to energy

    International Nuclear Information System (INIS)

    2002-09-01

    Matter is made up of atoms. In 1912, the English physicist Ernest Rutherford (who had shown that the atom had a nucleus), and the Danish physicist Niels Bohr developed a model in which the atom was made up of a positively charged nucleus surrounded by a cloud of electrons. In 1913, Rutherford discovered the proton, and in 1932, the English physicist Chadwick discovered the neutron. In 1938, Hahn and Strassmann discovered spontaneous fission and the French physicist Frederic Joliot-Curie, assisted by Lew Kowarski and Hans Von Halban, showed in 1939 that splitting uranium nuclei caused an intense release of heat. The discovery of the chain reaction would enable the exploitation of nuclear energy. 'It was the Second World War leaders who, by encouraging research for military purposes, contributed to the development of nuclear energy'. During the Second World War, from 1939 to 1945, studies of fission continued in the United States, with the participation of emigre physicists. The Manhattan project was launched, the aim of which was to provide the country with a nuclear weapon (used at Hiroshima and Nagasaki in 1945). After the war ended, research into energy production by the nuclear fission reaction continued for civil purposes. CEA (the French Atomic Energy Commission) was set up in France in 1945 under the impetus of General de Gaulle. This public research body is responsible for giving France mastery of the atom in the research, health, energy, industrial, safety and defense sectors. (authors)

  1. Fission-like events in the 12C+169Tm system at low excitation energies

    Science.gov (United States)

    Sood, Arshiya; Singh, Pushpendra P.; Sahoo, Rudra N.; Kumar, Pawan; Yadav, Abhishek; Sharma, Vijay R.; Shuaib, Mohd.; Sharma, Manoj K.; Singh, Devendra P.; Gupta, Unnati; Kumar, R.; Aydin, S.; Singh, B. P.; Wollersheim, H. J.; Prasad, R.

    2017-07-01

    Background: Fission has been found to be a dominating mode of deexcitation in heavy-ion induced reactions at high excitation energies. The phenomenon of heavy-ion induced fission has been extensively investigated with highly fissile actinide nuclei, yet there is a dearth of comprehensive understanding of underlying dynamics, particularly in the below actinide region and at low excitation energies. Purpose: Prime objective of this work is to study different aspects of heavy-ion induced fission ensuing from the evolution of composite system formed via complete and/or incomplete fusion in the 12C+169Tm system at low incident energies, i.e., Elab≈6.4 , 6.9, and 7.4 A MeV, as well as to understand charge and mass distributions of fission fragments. Method: The recoil-catcher activation technique followed by offline γ spectroscopy was used to measure production cross sections of fission-like events. The evaporation residues were identified by their characteristic γ rays and vetted by the decay-curve analysis. Charge and mass distributions of fission-like events were studied to obtain dispersion parameters of fission fragments. Results: In the present work, 26 fission-like events (32 ≤Z ≤49 ) were identified at different excitation energies. The mass distribution of fission fragments is found to be broad and symmetric, manifesting their production via compound nuclear processes. The dispersion parameters of fission fragments obtained from the analysis of mass and isotopic yield distributions are found to be in good accord with the reported values obtained for different fissioning systems. A self-consistent approach was employed to determine the isobaric yield distribution. Conclusions: The present work suggests that fission is one of the competing modes of deexcitation of complete and/or incomplete fusion composites at low excitation energies, i.e., E*≈57 , 63, and 69 MeV, where evaporation of light nuclear particle(s) and/or γ rays are assumed to be the sole

  2. Odd-even effect dependence on the excitation energy in low energy fission

    Science.gov (United States)

    Mirea, M.

    2017-09-01

    An inversion of the odd-even effect was observed experimentally in cold fission: the odd-odd fragmentation yields are favored over the even-even ones for excitations energies of the fragments smaller than 4 MeV. This effect is linked to the important problem of quasiparticle excitations during the dynamical evolution of the nuclear system from its ground-state configuration up to scission. An explanation based on the Landau-Zener promotion mechanism generalized for superfluid systems is offered for the inversion of the odd-even effect. In principle, the even-even fission products cannot be produced at very low excitation energies due dynamical quasiparticle excitations produced in the avoided- level-crossing regions. These excitations are produced with a large probability when the nuclear system deforms slowly.

  3. Intermediate energy proton and light-ion scattering

    International Nuclear Information System (INIS)

    Moss, J.M.

    1981-01-01

    A review is presented of recent (1979-81) developments in the field of intermediate-energy proton and light-ion scattering from nuclei. New theoretical and calculational techniques of particular interest to experimentalists are discussed. Emphasis is placed on topics in nuclear structure physics - giant resonances, pion-condensation precursor phenomena, and polarization transfer (spin-flip) experiments - where intermediate energy proton and light-ion scattering has made new and unique contributions

  4. Intermediate-energy neutron beams from reactors for NCT

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    This paper discusses ways that a beam of intermediate-energy neutrons might be extracted from a nuclear reactor. The challenge is to suppress the fast-neutron component and the gamma-ray component of the flux while leaving enough of the intermediate-energy neutrons in the beam to be able to perform neutron capture therapy in less than an hour exposure time. Moderators, filters, and reflectors are considered. 11 references, 7 figures, 3 tables

  5. Puzzling features of heavy-ion fission at sub-barrier energies

    Science.gov (United States)

    Samant, A. M.; Kailas, S.

    1996-12-01

    The heavy-ion induced fission fragment angular distributions measured for systems with Th, U and Np as targets have revealed “anomalous” values of anisotropies at energies E≤ V B (fusion barrier) and this feature is observed to be independent of the entrance channel mass-asymmetry. While this puzzling feature is exhibited by the deformed targets like Th, U and Np, most of the fission data measured for the spherical targets like Pb and Bi can be satisfactorily explained using the standard saddle point statistical model with moderate correction for pre-fission neutron emission. Plausible reasons for this anomalous behaviour are explored.

  6. (p,n) reaction at intermediate energy

    International Nuclear Information System (INIS)

    Goodman, C.D.

    1979-01-01

    The use of the (p,n) reaction in exploring effective interactions is reviewed. Some recent data on self-conjugate nuclei taken at the Indiana University Cyclotron Facility (IUCF) are presented, and the differences between low- and high-energy data are emphasized. Experimental problems and techniques used are briefly described. It is concluded that forward-angle (p,n) spectra at energies greater than 100 MeV are dominated by Gamow-Teller (GT) transitions, while Fermi transitions (IAS transitions) dominate near 45 MeV. Prominent GT transitions are expected from a pion-exchange interaction, and it is expected that OPEP is the dominant component of the interaction in the energy range of 100 to 200 MeV. 27 figures, 2 tables

  7. Charge distributions of fission fragments of low- and high-energy fission of Fm, No, and Rf isotopes

    Science.gov (United States)

    Paşca, H.; Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.

    2018-03-01

    The charge (mass) distributions of fission fragments resulting from low- and high-energy fission of the even-even nuclei 254 -260 ,264Fm , 258 -264No , and 262 -266Rf are studied with the statistical scission-point model. The calculated results are compared with the available experimental data. In contrast to the experimental data, the calculated mass distribution for 258Fm (s.f.) is strikingly similar to the experimental one for 257Fm (s.f.). The transformation of the shape of charge distribution with increasing isospin and excitation energy occurs gradually and in a similar fashion like that of the mass distribution, but slower. For 254Fm(i.f.), 257Fm(nt h,f), and 260Fm (s.f.), the unexpected difference (symmetric or asymmetric) between the shapes of charge and mass distributions is predicted for the first time. At some critical excitation energy, the saturation of the symmetric component of charge (mass) yields is demonstrated.

  8. Total Kinetic Energy and Fragment Mass Distribution of Neutron-Induced Fission of U-233

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, Daniel James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schmitt, Kyle Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tovesson, Fredrik [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-29

    Properties of fission in U-233 were studied at the Los Alamos Neutron Science Center (LANSCE) at incident neutron energies from thermal to 40 MeV at both the Lujan Neutron Scattering Center flight path 12 and at WNR flight path 90-Left from Dec 2016 to Jan 2017. Fission fragments are observed in coincidence using a twin ionization chamber with Frisch grids. The average total kinetic energy (TKE) released from fission and fragment mass distributions are calculated from observations of energy deposited in the detector and conservation of mass and momentum. Accurate experimental measurements of these parameters are necessary to better understand the fission process and obtain data necessary for calculating criticality. The average TKE released from fission has been well characterized for several isotopes at thermal neutron energy, however, few measurements have been made at fast neutron energies. This experiment expands on previous successful experiments using an ionization chamber to measure TKE and fragment mass distributions of U-235, U-238, and Pu-239. This experiment requires the full spectrum of neutron energies and can therefore only be performed at a small number of facilities in the world. The required full neutron energy spectrum is obtained by combining measurements from WNR 90L and Lujan FP12 at LANSCE.

  9. Accurate isotopic fission yields of electromagnetically induced fission of 238U measured in inverse kinematics at relativistic energies

    Science.gov (United States)

    Pellereau, E.; Taïeb, J.; Chatillon, A.; Alvarez-Pol, H.; Audouin, L.; Ayyad, Y.; Bélier, G.; Benlliure, J.; Boutoux, G.; Caamaño, M.; Casarejos, E.; Cortina-Gil, D.; Ebran, A.; Farget, F.; Fernández-Domínguez, B.; Gorbinet, T.; Grente, L.; Heinz, A.; Johansson, H.; Jurado, B.; Kelić-Heil, A.; Kurz, N.; Laurent, B.; Martin, J.-F.; Nociforo, C.; Paradela, C.; Pietri, S.; Rodríguez-Sánchez, J. L.; Schmidt, K.-H.; Simon, H.; Tassan-Got, L.; Vargas, J.; Voss, B.; Weick, H.

    2017-05-01

    SOFIA (Studies On Fission with Aladin) is a novel experimental program, dedicated to accurate measurements of fission-fragment isotopic yields. The setup allows us to fully identify, in nuclear charge and mass, both fission fragments in coincidence for the whole fission-fragment range. It was installed at the GSI facility (Darmstadt), to benefit from the relativistic heavy-ion beams available there, and thus to use inverse kinematics. This paper reports on fission yields obtained in electromagnetically induced fission of 238U.

  10. 14. International workshop on nuclear fission physics. Proceedings

    International Nuclear Information System (INIS)

    2000-01-01

    The meetings on nuclear fission took place 12-15 October 1998 and was organized by Institute of Physics and Power Engineering. The aim of the workshop was to present and discuss main new both theoretical and experimental results obtained in the area of nuclear fission, dynamical feature, properties of fission fragments and complementary radiation. As usual the program of the workshop was designed to cover a wide range of physical phenomena - from low energy and spontaneous fission to fission of hot rotating nuclei and multifragmentation at intermediate and high energies. Reaction induced by slow and fast neutron, light and heavy ions were discussed [ru

  11. Heavy ion collisions at intermediate energy

    International Nuclear Information System (INIS)

    Bertsch, G.; Amsden, A.A.

    1978-01-01

    Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

  12. Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    Vary, J.P.

    1992-01-01

    Progress during the last year is reviewed under the following topics: relativistic hadron--nucleus and nucleus--nucleus collisions (heavy meson production, photon production and fragmentation functions--direct photon production with the QCM and photon fragmentation functions, Cronin efffect and multiple scattering, effective nuclear parton distributions); solving quantum field theories in nonperturbative regime; light-front dynamics and high-spin states (soft form factor of the pion and nucleon for transverse and longitudinal momentum transfers, light front spinors for high-spin objects); high-energy spin physics; relativistic wave equations, quarkonia, and e + e - resonances; associated production of Higgs boson at collider energies, and microscopic nuclear many-body theory and reactions. 135 refs

  13. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin James [Univ. of California, Berkeley, CA (United States)

    2010-04-08

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 μm of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles

  14. Innovative spin precessor for intermediate energy protons

    International Nuclear Information System (INIS)

    Hoffman, E.W.

    1979-01-01

    A spin precessor has been designed to provide arbitrary orientation of the polarization in the external proton beam at LAMPF. The device utilizes two superconducting solenoids, three conventional dipoles, and conversion of polarized H - to H + to provide an achromatic, undeflected beam with tunable spin orientation over a range of energies from 400 MeV to 800 MeV. A portion of this device is being installed to provide compatibility between two facilities which simultaneously use two branches of the external proton beam at LAMPF

  15. Role of near threshold resonances in intermediate energy nuclear ...

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Abstract. The presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of 12C, the element for life, in 4He burning in. Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the ...

  16. Hard photon as probes of intermediate energy heavy ion reactions

    International Nuclear Information System (INIS)

    Siemssen, R.H.

    1996-01-01

    Some recent results on the production of hard photons in intermediate energy heavy-ion reactions are reported. The topics covered are the use of hard photons as a means to study the energy dissipation mechanism in peripheral heavy ion reactions and the observation of second chance or thermal hard photons

  17. Measurements of angular and energy distributions of prompt neutrons from thermal neutron-induced fission

    Science.gov (United States)

    Vorobyev, A. S.; Shcherbakov, O. A.; Pleva, Yu. S.; Gagarski, A. M.; Val'ski, G. V.; Petrov, G. A.; Petrova, V. I.; Zavarukhina, T. A.

    2009-01-01

    The experimental setup and methodology used to measure prompt neutron angular and energy distributions from thermal neutron-induced fission are described. The neutrons are detected using two scintillation detectors, while the fission fragments are detected by multi-wire proportional detectors in conjunction with the TOF technique. To separate events corresponding to neutrons and γ-quanta, a double discrimination by the pulse shape and the time-of-flight is applied. Some preliminary results of an experiment performed with the 235U target are presented and briefly discussed. The yield of "scission" neutrons has been estimated in the framework of a simple evaporation model and was found not to exceed 5% of the total neutron yield. Including an assumed of anisotropy of the fission neutron angular distribution in the center-of-mass system of fission fragments into the model calculation leads to an increase in the "scission" neutron yields inferred from the data.

  18. Current estimates of the energy released following the fission of actinide nuclides

    Science.gov (United States)

    Sonzogni, Alejandro; McCutchan, Elizabeth

    2017-09-01

    We calculate the energy released following the neutron induced fission of the main fuel nuclides in a reactor, 235U, 238U, 239Pu and 241Pu. These energies are used in a number of fields, but we were particularly motivated by their application in the recent measurements of reactor antineutrinos spectra and yields. The calculations are performed using the best estimates of cumulative fission yields for long-lived fission products and the recently released 2016 Atomic Mass Evaluation by Wang et al. Additionally, we obtain more precise values of the energy taken away by antineutrinos by using the latest Total Absorption Gamma Spectroscopy (TAGS) results. An important part of this project is also to obtain realistic estimates of the uncertainties. A comparison with earlier calculations will be presented. Work at Brookhaven National Laboratory was sponsored by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DE-AC0298CH10886.

  19. Heavy residue properties in intermediate energy nuclear collisions with gold

    International Nuclear Information System (INIS)

    Aleklett, K.; Sihver, L.; Liljenzin, J.O.; Seaborg, G.T.

    1990-10-01

    We have measured the target fragment production cross sections and angular distributions for the interaction of 32, 44 and 93 MeV/nucleon argon, 35 and 43 MeV/nucleon krypton with gold. The fragment isobaric yield distributions, moving frame angular distributions and velocities have been deduced from these data. This fission cross section decreases with increasing projectile energy and the heavy residue cross section increases. The ratio v parallel /v cn increases approximately linearly with mass removed from the target. 21 refs., 8 figs

  20. Light fragment formation at intermediate energies

    International Nuclear Information System (INIS)

    Boal, D.H.

    1982-03-01

    This paper concerns itself mainly with the production of energetic protons and light fragments at wide angles. The experiments point to nucleon emission in proton-induced reactions as involving a mechanism in which the observed nucleon is directly knocked out of the nucleus. A similar feature seems to be required to explain (p,F) and (e,F) reactions: an energetic nucleon is produced in one scattering of the projectile, and the struck nucleon subsequently loses some of its energy as it traverses the remaining part of the nucleus, gathering up other nucleons as it goes, to become a fragment. This is what one might call the extreme snowball model, and a more accurate description probably involves multiple scattering of the projectile in addition to the extreme snowball contribution. This will be particularly true for fragments in the mass 6 to 9 region. This scenario also appears to apply to deuteron-induced fragment production. However, for alpha-induced reactions it would appear that the nucleons forming a fragment can originate from collisions involving different incident nucleons in the projectile. For heavy ions, this effect is even stronger, and the snowball contribution is greatly reduced compared to that of the traditional coalescence model

  1. [Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    1987-01-01

    We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. We have solved a non-trivial model field theory in the strong coupling regime using a discretized light front quantization (DLFQ) scheme. The method we developed expands upon the method of Pauli and Brodsky by incorporating a dynamical treatment of the vacuum. This is a major result since we have shown directly that the light-cone vacuum is not structureless as has been traditionally claimed by some particle theorists. We have thus succeeded in elucidating the consequences of spontaneous symmetry breaking in light-cone quantization. We now propose to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We will complete our analysis of the SLAC NE3 data to explicate the degree to which they confirm the QCM prediction of ''steps'' in the ratio of nuclear structure functions when Bjorken x exceeds unity. In another effort, we will perform a search for narrow resonances in electron-positron interactions high in the continuum using the Bethe-Salpeter equation. We have completed our development of microscopic effective Hamiltonians for nuclear structure which include the explicit treatment of delta resonances. These effective Hamiltonians were successfully used in constrained mean field calculations evaluating conditions for nuclei to undergo a transition from nucleon matter to delta matter. 73 refs

  2. Intermediate-energy neutron beam for NCT at MURR

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    The University of Missouri Research Reactor (MURR) is one of the high-flux reactors in the USA and it can be used to produce an intense beam of intermediate-energy neutrons for neutron capture therapy. Two methods are being evaluated at MURR to produce such a beam. The first uses a moderator of Al 2 O 3 replacing part of the graphite and water on one side of the core of the reactor to produce a source of predominantly intermediate-energy neutrons. The second method is a filter of 238 U between the core and the patient position to pass only intermediate-energy neutrons. The results of these evaluations are presented in this paper along with an outline of the other resources at the University of Missouri-Columbia that are available to support an NCT program. 4 references, 7 figures, 1 table

  3. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    International Nuclear Information System (INIS)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt; Audouin, Laurent; Tassan-Got, Laurent; Aumann, Thomas; Casarejos, Enrique; Farget, Fanny; Rodriguez-Tajes, Carme; Heinz, Andreas; Jurado, Beatriz; Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut

    2015-01-01

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  4. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric [CEA DAM Bruyeres-le-Chatel, Arpajon (France); Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, Laurent; Tassan-Got, Laurent [CNRS/IN2P3, IPNO, Orsay (France); Aumann, Thomas [Technische Universitaet Darmstadt, Darmstadt (Germany); Casarejos, Enrique [Universidad de Vigo, Vigo (Spain); Farget, Fanny; Rodriguez-Tajes, Carme [CNRS/IN2P3, GANIL, Caen (France); Heinz, Andreas [Chalmers University of Technology, Gothenburg (Sweden); Jurado, Beatriz [CNRS/IN2P3, CENBG, Gradignan (France); Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2015-12-15

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  5. Improved fission neutron energy discrimination with {sup 4}He detectors through pulse filtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ting, E-mail: ting.zhu@ufl.edu [University of Florida, Gainesville, FL (United States); Liang, Yinong; Rolison, Lucas; Barker, Cathleen; Lewis, Jason; Gokhale, Sasmit [University of Florida, Gainesville, FL (United States); Chandra, Rico [Arktis Radiation Detectors Ltd., Räffelstrasse 11, Zürich (Switzerland); Kiff, Scott [Sandia National Laboratories, CA (United States); Chung, Heejun [Korean Institute for Nuclear Nonproliferation and Control, 1534 Yuseong-daero, Yuseong-gu, Daejeon (Korea, Republic of); Ray, Heather; Baciak, James E.; Enqvist, Andreas; Jordan, Kelly A. [University of Florida, Gainesville, FL (United States)

    2017-03-11

    This paper presents experimental and computational techniques implemented for {sup 4}He gas scintillation detectors for induced fission neutron detection. Fission neutrons are produced when natural uranium samples are actively interrogated by 2.45 MeV deuterium-deuterium fusion reaction neutrons. Fission neutrons of energies greater than 2.45 MeV can be distinguished by their different scintillation pulse height spectra since {sup 4}He detectors retain incident fast neutron energy information. To enable the preferential detection of fast neutrons up to 10 MeV and suppress low-energy event counts, the detector photomultiplier gain is lowered and trigger threshold is increased. Pile-up and other unreliable events due to the interrogating neutron flux and background radiation are filtered out prior to the evaluation of pulse height spectra. With these problem-specific calibrations and data processing, the {sup 4}He detector's accuracy at discriminating fission neutrons up to 10 MeV is improved and verified with {sup 252}Cf spontaneous fission neutrons. Given the {sup 4}He detector's ability to differentiate fast neutron sources, this proof-of-concept active-interrogation measurement demonstrates the potential of special nuclear materials detection using a {sup 4}He fast neutron detection system.

  6. HETFIS: High-Energy Nucleon-Meson Transport Code with Fission

    Energy Technology Data Exchange (ETDEWEB)

    Barish, J.; Gabriel, T.A.; Alsmiller, F.S.; Alsmiller, R.G. Jr.

    1981-07-01

    A model that includes fission for predicting particle production spectra from medium-energy nucleon and pion collisions with nuclei (Z greater than or equal to 91) has been incorporated into the nucleon-meson transport code, HETC. This report is primarily concerned with the programming aspects of HETFIS (High-Energy Nucleon-Meson Transport Code with Fission). A description of the program data and instructions for operating the code are given. HETFIS is written in FORTRAN IV for the IBM computers and is readily adaptable to other systems.

  7. Accelerator-driven thermal fission systems may provide energy supply advantages

    International Nuclear Information System (INIS)

    Linford, R.K.

    1992-01-01

    This presentation discusses the energy supply advantages of using accelerator-driven thermal fission systems. Energy supply issues as related to cost, fuel supply stability, environmental impact, and safety are reviewed. It is concluded that the Los Alamos Accelerator Transmutation of Waste (ATW) concept, discussed here, has the following advantages: improved safety in the form of low inventory and subcriticality; reduced high-level radioactive waste management timescales for both fission products and actinides; and a very long-term fuel supply requiring no enrichment

  8. Nuclear fission energy: the international scene and the outlook for Italy

    International Nuclear Information System (INIS)

    Monti, S.

    2008-01-01

    Because of concerns about the environment, energy security and energy costs, fission nuclear energy is gaining ground again around the world. In Italy, the research community can help relaunch the national nuclear programmes by providing advanced training, recruiting young engineers and researchers for RD activities, and furthering an immediate cooperation of the Italian system in the principal European and international projects on sustainable nuclear energy [it

  9. Theoretical research in intermediate energy nuclear physics: Final report

    International Nuclear Information System (INIS)

    Seki, R.

    1987-01-01

    This paper discusses the progress that has been made on the following problems: a numerical calculation of Skyrmiron scattering; (e,e'p) at high momentum transfer; spin-orbit nucleon-nucleon potential from Skyrme model; pionic atom anomaly; and field theory problems. The problems deal with various topics in intermediate-energy nuclear physics

  10. Proceedings of the 5. National Meeting on Intermediate Energy Physics

    International Nuclear Information System (INIS)

    1984-05-01

    Several papers concerning the physics at intermediate energies (∼ 100-1000MeV) are presented in this proceedings. Almost all the works show overlapping between Nuclear and Particles Physics. There is a predominance in theoretical papers. (L.C.) [pt

  11. Electron emission in collisions of intermediate energy ions with atoms

    International Nuclear Information System (INIS)

    Garibotti, C.R.

    1988-01-01

    The aim of this work, is the analysis of the processes of electronic emission produced in the collisions of small ions (H + , He ++ ) of intermediate energy (50 a 200 KeV/amu) with light gaseous targets. (A.C.A.G.) [pt

  12. Multiplicity and correlated energy of gamma rays emitted in the spontaneous fission of Californium-252

    International Nuclear Information System (INIS)

    Brunson, G.S. Jr.

    1982-06-01

    An array of eight high-speed plastic scintillation detectors has been used to infer a mathematical model for the emission multipliciy of prompt gammas in the spontaneous fission of 252 Cf. Exceptional time resolution and coincidence capability permitted the separation of gammas from fast neutrons over a flight path of approximately 10 cm. About 20 different distribution models were tested. The average energy of the prompt gammas is inversely related to the number emitted; however, this inverse relationship is not strong and the total gamma energy does increase with increasing gamma number. An extension of the experiment incorporated a lithium-drifted germanium gamma spectrometer that resolved nearly 100 discrete gammas associated with fission. Of these gammas, some were preferentially associated with fission in which few gammas were emitted. Certain others were more frequent when many gammas were emitted. Results are presented

  13. Theoretical energy straggling of /sup 252/Cf fission fragments in various absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Al-Bedri, M.B.; Al-Hindawi, K.A.A. (Baghdad Univ. (Iraq). Dept. of Physics)

    1982-07-15

    A new theoretical formula of energy straggling for heavy ions such as /sup 252/Cf fission fragments in various stopping media has been calculated in terms of incident heavy ion energy, differential scattering cross-section, electronic and nuclear stopping cross-section. However, no theory yet exists which is cabable of predicting straggling behaviour of fission fragments. Comparison between our theoretical predictions and the previous work of Al-Bedri and Sykes has been made. Good agreement has been achieved at the beginning of the range of fission fragments but towards the end of the range our theoretical results were greater than the experimental results by about 10-20%. This discrepancy could be caused by the stopping cross-section, because the experimental stopping cross-section is greater than the theoretical data by about 0-30%.

  14. Collective spectra along the fission barrier

    Directory of Open Access Journals (Sweden)

    Pigni M. T.

    2012-12-01

    Full Text Available Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states and in the intermediate wells (superdeformed and hyperdeformed states play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two–cluster configurations in a dynamical way, permitting exchange of upper–shell nucleons between clusters. The impact of theoretical spectra on neutron–induced fission cross sections and, in combination with an improved version of the scission–point model, on angular distribution of fission fragments is evaluated for plutonium isotopes of interest to nuclear energy applications.

  15. Collective spectra along the fission barrier

    Science.gov (United States)

    Shneidman, T. M.; Andreev, A. V.; Pigni, M. T.; Massimi, C.; Vannini, G.; Ventura, A.

    2012-12-01

    Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states) and in the intermediate wells (superdeformed and hyperdeformed states) play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of upper-shell nucleons between clusters. The impact of theoretical spectra on neutron-induced fission cross sections and, in combination with an improved version of the scission-point model, on angular distribution of fission fragments is evaluated for plutonium isotopes of interest to nuclear energy applications.

  16. Four-dimensional Langevin approach to low-energy nuclear fission of 236U

    Science.gov (United States)

    Ishizuka, Chikako; Usang, Mark D.; Ivanyuk, Fedir A.; Maruhn, Joachim A.; Nishio, Katsuhisa; Chiba, Satoshi

    2017-12-01

    We developed a four-dimensional (4D) Langevin model, which can treat the deformation of each fragment independently and applied it to low-energy fission of 236U, the compound system of the reaction n +235U . The potential energy is calculated with the deformed two-center Woods-Saxon (TCWS) and the Nilsson-type potential with the microscopic energy corrections following the Strutinsky method and BCS pairing. The transport coefficients are calculated by macroscopic prescriptions. It turned out that the deformation for the light and heavy fragments behaves differently, showing a sawtooth structure similar to that of the neutron multiplicities of the individual fragments ν (A ) . Furthermore, the measured total kinetic energy TKE (A ) and its standard deviation are reproduced fairly well by the 4D Langevin model based on the TCWS potential in addition to the fission fragment mass distributions. The developed model allows a multiparametric correlation analysis among, e.g., the three key fission observables, mass, TKE, and neutron multiplicity, which should be essential to elucidate several longstanding open problems in fission such as the sharing of the excitation energy between the fragments.

  17. Theory and applications of the fission matrix method for continuous-energy Monte Carlo

    International Nuclear Information System (INIS)

    Carney, Sean; Brown, Forrest; Kiedrowski, Brian; Martin, William

    2014-01-01

    Highlights: • The fission matrix method is implemented into the MCNP Monte Carlo code. • Eigenfunctions and eigenvalues of power distributions are shown and studied. • Source convergence acceleration is demonstrated for a fuel storage vault problem. • Forward flux eigenmodes and relative uncertainties are shown for a reactor problem. • Eigenmodes expansions are performed during source convergence for a reactor problem. - Abstract: The fission matrix method can be used to provide estimates of the fundamental mode fission distribution, the dominance ratio, the eigenvalue spectrum, and higher mode forward and adjoint eigenfunctions of the fission distribution. It can also be used to accelerate the convergence of power method iterations and to provide basis functions for higher-order perturbation theory. The higher-mode fission sources can be used to determine higher-mode forward fluxes and tallies, and work is underway to provide higher-mode adjoint-weighted fluxes and tallies. These aspects of the method are here both theoretically justified and demonstrated, and then used to investigate fundamental properties of the transport equation for a continuous-energy physics treatment. Implementation into the MCNP6 Monte Carlo code is also discussed, including a sparse representation of the fission matrix, which permits much larger and more accurate representations. Properties of the calculated eigenvalue spectrum of a 2D PWR problem are discussed: for a fine enough mesh and a sufficient degree of sampling, the spectrum both converges and has a negligible imaginary component. Calculation of the fundamental mode of the fission matrix for a fuel storage vault problem shows how convergence can be accelerated by over a factor of ten given a flat initial distribution. Forward fluxes and the relative uncertainties for a 2D PWR are shown, both of which qualitatively agree with expectation. Lastly, eigenmode expansions are performed during source convergence of the 2D PWR

  18. Role of energy cost in the yield of cold ternary fission of Cf

    Indian Academy of Sciences (India)

    Role of energy cost in the yield of cold ternary fission of. 252. Cf. P V KUNHIKRISHNAN1 and K P SANTHOSH2,∗. 1P.G. Department of Physics, Sree Narayana College, Kannur 670 007, India. 2School of Pure & Applied Physics, Kannur University, Payyanur Campus,. Payyanur 670 327, India. ∗. Corresponding author.

  19. Inelastic α-particle scattering at intermediate energy

    International Nuclear Information System (INIS)

    Bauer, T.S.; Beurtey, R.; Boudard, A.; Bruge, G.; Catz, H.; Couvert, P.; Escudie, J.L.; Fontaine, J.M.; Garcon, M.; Lugol, J.C.; Matoba, M.; Platchkov, S.; Rouger, M.; Terrien, Y.

    1979-01-01

    The rigid body approximation is used to extend the Glauber formalism to the analysis of inelastic scattering of 1.37 GeV α particles by 24 Mg and 58 Ni. Angular distributions for low-lying states in 24 Mg and 58 Ni are analyzed in this framework together with previously published data for Ca isotopes. Intermediate energy α particle scattering is tested as a tool to observe the isoscalar giant quadrupole resonance. Energy weighted sum rules are drawn from the analysis of L = 2 angular distributions measured in the proper energy range. Comparison is made with existing data

  20. Influence of primary fragment excitation energy and spin distributions on fission observables

    Science.gov (United States)

    Litaize, Olivier; Thulliez, Loïc; Serot, Olivier; Chebboubi, Abdelaziz; Tamagno, Pierre

    2018-03-01

    Fission observables in the case of 252Cf(sf) are investigated by exploring several models involved in the excitation energy sharing and spin-parity assignment between primary fission fragments. In a first step the parameters used in the FIFRELIN Monte Carlo code "reference route" are presented: two parameters for the mass dependent temperature ratio law and two constant spin cut-off parameters for light and heavy fragment groups respectively. These parameters determine the initial fragment entry zone in excitation energy and spin-parity (E*, Jπ). They are chosen to reproduce the light and heavy average prompt neutron multiplicities. When these target observables are achieved all other fission observables can be predicted. We show here the influence of input parameters on the saw-tooth curve and we discuss the influence of a mass and energy-dependent spin cut-off model on gamma-rays related fission observables. The part of the model involving level densities, neutron transmission coefficients or photon strength functions remains unchanged.

  1. Transport code and nuclear data in intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Akira; Odama, Naomitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Maekawa, F.; Ueki, K.; Kosaka, K.; Oyama, Y.

    1998-11-01

    We briefly reviewed the problems of intermediate energy nuclear data file and transport codes in connection with processing of the data. This is a summary of our group in the task force on JENDL High Energy File Integral Evaluation (JHEFIE). In this article we stress the necessity of the production of intermediate evaluated nuclear data file up to 3 GeV for the application of accelerator driven transmutation (ADT) system. And also we state the necessity of having our own transport code system to calculate the radiation fields using these evaluated files from the strategic points of view to keep our development of the ADT technology completely free from other conditions outside of our own such as imported codes and data with poor maintenance or unknown accuracy. (author)

  2. Investigation of incomplete linear momentum transfer in heavy ion reactions at intermediate energies

    International Nuclear Information System (INIS)

    Leray, S.

    1986-07-01

    At intermediate energies, heavy ion central collisions lead to the incomplete fusion of the incident nuclei while part of the initial linear momentum is carried away by fast light particles. Experiments were performed with 30 MeV per nucleon neon and 20, 35 and 44 MeV per nucleon argon projectiles bombarding heavy targets. Results obtained with 30 MeV per nucleon neon and 20 MeV per nucleon argon beams are in good agreement with an empirical law established with lighter projectiles. On the contrary, 35 and 44 MeV per nucleon argon projectiles do not follow the same law and fission fragments progressively disappear. A simple model explains the evolution of the amount of transferred linear momentum versus incident energy. The disappearance of the fusion products of the composite system observed with argon projectiles beyond 35 MeV per nucleon is explained by a limitation of the excitation energy per nucleon which can be deposited in a nucleus. The limit is evaluated from nucleon binding energy in nuclei and probability to emit clusters and is in good agreement with experimental data. Because of the coupling between intrinsic motion of nucleons and relative motion of nuclei, some nucleons have a kinetic energy high enough to be emitted: a theoretical model is proposed which rather well fits the data concerning fast nucleons but cannot explain the measured amounts of transferred linear momentum. This is attributed to the existence of other mechanisms [fr

  3. ''Super-radiant'' states in intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    Auerbach, N.

    1994-01-01

    A ''super-radiant'' state emerges when, under certain conditions, one or a few ''internal'' states acquire a large collective decay width due to the coupling to one or a few ''external'' decay channels. The rest of the internal states are ''stripped'' of their decay width and become long lived quasistationary states. The essentials of such mechanism and its possible role in intermediate energy nuclear physics are discussed in this work

  4. Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments

    Science.gov (United States)

    Tarditi, A. G.; George, J. A.; Miley, G. H.; Scott, J. H.

    2013-01-01

    Fission fragment direct energy conversion has been considered in the past for the purpose of increasing nuclear power plant efficiency and for advanced space propulsion. Since the fragments carry electric charge (typically in the order of 20 e) and have 100 MeV-range kinetic energy, techniques utilizing very high-voltage DC electrodes have been considered. This study is focused on a different approach: the kinetic energy of the charged fission fragments is converted into alternating current by means of a traveling wave coupling scheme (Traveling Wave Direct Energy Converter, TWDEC), thereby not requiring the utilization of high voltage technology. A preliminary feasibility analysis of the concept is introduced based on a conceptual level study and on a particle simulation model of the beam dynamics.

  5. Fission excitation function for 19F + 194,196,198Pt at near and above barrier energies

    Directory of Open Access Journals (Sweden)

    Singh Varinderjit

    2015-01-01

    Full Text Available Fission excitation functions for 19F + 194,196,198Pt reactions populating 213,215,217Fr compound nuclei are reported. Out of these three compound nuclei, 213Fr is a shell closed (N=126 compound nucleus and the other two are away from the shell closure. From a comparison of the experimental fission cross-sections with the statistical model predictions, it is observed that the fission cross-sections are underestimated by the statistical model predictions using shell corrected finite range rotating liquid drop model (FRLDM fission barriers. Further the FRLDM fission barriers are reduced to fit the fission cross-sections over the entire measured energy range.

  6. Conceptual design of a hybrid fusion-fission reactor with intrinsic safety and optimized energy productivity

    International Nuclear Information System (INIS)

    Talebi, Hosein; Sadat Kiai, S.M.

    2017-01-01

    Highlights: • Designing a high yield and feasible Dense Plasma Focus for driving the reactor. • Presenting a structural method to design the dual layer cylindrical blankets. • Finding, the blanket production energy, in terms of its geometrical and material parameters. • Designing a subcritical blanket with optimization of energy amplification in detail. - Abstract: A hybrid fission-fusion reactor with a Dense Plasma Focus (DPF) as a fusion core and the dual layer fissionable blanket as the energy multiplier were conceptually designed. A cylindrical DPF, energized by a 200 kJ bank energy, is considered to produce fusion neutron, and these neutrons drive the subcritical fission in the surrounding blankets. The emphasis has been placed on the safety and energy production with considering technical and economical limitations. Therefore, the k eff-t of the dual cylindrical blanket was defined and mathematically, specified. By applying the safety criterion (k eff-t ≤ 0.95), the geometrical and material parameters of the blanket optimizing the energy amplification were obtained. Finally, MCNPX code has been used to determine the detailed dimensions of the blankets and fuel rods.

  7. Is nuclear fission energy at all needed. I

    International Nuclear Information System (INIS)

    Valvoda, Z.

    1978-01-01

    The history is shown of the primary energy consumption per head of population, the world consumption of primary energy in 1950 and 1970, rough estimate of the past and future demand for primary energy in the world, and the actual and estimated development of the size of population and the demand for primary energy in the world. For comparison, the history is shown of the primary energy consumption per capita in advanced and developing countries in 1955, 1965, 1969, 2000, and the primary energy consumption is compared for industrially advanced and developing countries in 1970. Also shown are energy consumption required for the production of some materials (cement, aluminium, copper, plastics, etc.), ore exploitation in the world in 1953, 1960, 1965 and 1968, the specific energy consumption for different transport systems in terms of petrol, the actual and estimated consumption of electric power in the years 1900 to 2000, gross electric power generation in the world classified in main areas, the history of gross electric power generation per head of population in some countries, and the consumption of electric power in some countries' industries in the years 1969 to 1973. (J.P.)

  8. The Commission's research action programme on the development of nuclear fission energy

    International Nuclear Information System (INIS)

    1984-01-01

    For its 'Framework Programme 1984-1987' the Commission has defined the major goals for a European Scientific and Technical Strategy. One of the means to reduce the energy dependence of the Community, which is an important objective, is to favour the development of nuclear fission energy. As electricity production by nuclear reactors has reached industrial maturity, the Community activities are directed mainly to safety aspects, in order to ensure the protection of workers and the general public, against hazards linked to operations in the nuclear fuel cycle. A description of the main features of the five sub-programmes on nuclear fission energy is given below; these programmes are: reactor safety; nuclear fuels and actinides research; management of radioactive waste; safeguarding and management of fissile materials; decommissioning of nuclear installations. The research and development work is carried out either by the Commission's Joint Research Center or by organizations and companies of the Member Countries, with the Commission's financial support. (author)

  9. The radial shapes of intermediate energy microscopic optical potentials

    International Nuclear Information System (INIS)

    Shen Qingbiao; Wang Chang; Tian Ye; Zhuo Yizhong

    1984-01-01

    The radial shapes of intermediate energy proton microscopic optical potentials of 40 Ca are calculated with nuclear matter approach by Skyrme interactions. The calculated results show that the real central potential in central region of nucleus changes from attractive to repulsive when the energy of incident nucleon is above 150 MeV and appears apparently a 'wine-bottle-bottom' shape in the transition energy region (from 150 MeV to 300 MeV). This tendency is consistent with empirical optical potential obtained through fitting experiments and microscopic optical potential calculated with relativistic mean field theory as well as with the BHF theory. The calculated imaginary part of the microscopic optical potential changes from the dominant surface absorption into the volume absorption and its absolute value become larger as energy increases. The effects of Skyrme force parameters to the radial shape of the calculated microscopic optical potential are analysed in detail

  10. The Fukushima nuclear disaster and its effects on media framing of fission and fusion energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Luisa; Horta, Ana; Pereira, Sergio; Delicado, Ana [Institute of Social Sciences of the University of Lisbon, Av. Prof. Anibal de Bettencourt, 9 1600-189 Lisbon (Portugal)

    2015-07-01

    This paper presents results of a comparison of media coverage of fusion and fission energy technologies in three countries (Germany, Spain and Portugal) and in the English language international print media addressing transnational elite, from 2008 to 2012. The analysis showed that the accident in Fukushima in March 2010 did not have significant impact on media framing of nuclear fusion in the major part of print media under investigation. In fact, fusion is clearly dissociated from traditional nuclear (fission) energy and from nuclear accidents. It tends to be portrayed as a safe, clean and unlimited source of energy, although less credited when confronted with research costs, technological feasibility and the possibility to be achieved in a reasonable period of time. On the contrary, fission is portrayed as a hazardous source of energy, expensive when compared to research costs of renewables, hardly a long-term energy option, susceptible to contribute to the proliferation of nuclear weapons or rogue military use. Fukushima accident was consistently discussed in the context of safety problems of nuclear power plants and in many cases appeared not as an isolated event but rather as a reminder of previous nuclear disasters such as Three Miles Island and Chernobyl. (authors)

  11. The Fukushima nuclear disaster and its effects on media framing of fission and fusion energy technologies

    International Nuclear Information System (INIS)

    Schmidt, Luisa; Horta, Ana; Pereira, Sergio; Delicado, Ana

    2015-01-01

    This paper presents results of a comparison of media coverage of fusion and fission energy technologies in three countries (Germany, Spain and Portugal) and in the English language international print media addressing transnational elite, from 2008 to 2012. The analysis showed that the accident in Fukushima in March 2010 did not have significant impact on media framing of nuclear fusion in the major part of print media under investigation. In fact, fusion is clearly dissociated from traditional nuclear (fission) energy and from nuclear accidents. It tends to be portrayed as a safe, clean and unlimited source of energy, although less credited when confronted with research costs, technological feasibility and the possibility to be achieved in a reasonable period of time. On the contrary, fission is portrayed as a hazardous source of energy, expensive when compared to research costs of renewables, hardly a long-term energy option, susceptible to contribute to the proliferation of nuclear weapons or rogue military use. Fukushima accident was consistently discussed in the context of safety problems of nuclear power plants and in many cases appeared not as an isolated event but rather as a reminder of previous nuclear disasters such as Three Miles Island and Chernobyl. (authors)

  12. Disappearance of entrance channel dependence of fission fragment anisotropies at well-above-barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Vandenbosch, R.; Bierman, J.D.; Lestone, J.P.; Liang, J.F.; Prindle, D.J.; Sonzogni, A.A. [University of Washington, Nuclear Physics Laboratory, Seattle, Washington 98195 (United States); Kailas, S.; Nadkarni, D.M.; Kapoor, S.S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Bombay-400085 (India)

    1996-09-01

    Fission fragment anisotropies have been measured to energies extending well above the barrier for three entrance channels leading to the same compound nucleus {sup 248}Cf. For the {sup 12}C + {sup 236}U and {sup 16}O + {sup 232}Th systems, lying on either side of the Businaro-Gallone critical asymmetry, the mean square angular momentum is matched at an excitation energy of 62 MeV. The anisotropies, although different at lower energies, are in agreement within experimental errors at this excitation energy and thus show no entrance channel dependence. {copyright} {ital 1996 The American Physical Society.}

  13. Fifty years of nuclear fission: Nuclear data and measurements series

    International Nuclear Information System (INIS)

    Lynn, J.E.

    1989-06-01

    This report is the written version of a colloquium first presented at Argonne National Laboratory in January 1989. The paper begins with an historical preamble about the events leading to the discovery of nuclear fission. This leads naturally to an account of early results and understanding of the fission phenomena. Some of the key concepts in the development of fission theory are then discussed. The main theme of this discussion is the topography of the fission barrier, in which the interplay of the liquid-drop model and nucleon shell effects lead to a wide range of fascinating phenomena encompassing metastable isomers, intermediate-structure effects in fission cross-sections, and large changes in fission product properties. It is shown how study of these changing effects and theoretical calculations of the potential energy of the deformed nucleus have led to broad qualitative understanding of the nature of the fission process. 54 refs., 35 figs

  14. Fission fragment angular distribution measurements for 16O + 194Pt reaction at energies near the Coulomb barrier

    Science.gov (United States)

    Prasad, E.; Varier, K. M.; Thomas, R. G.; Vinodkumar, A. M.; Mahata, K.; Appannababu, S.; Sugathan, P.; Golda, K. S.; Babu, B. R. S.; Saxena, A.; John, B. V.; Kailas, S.

    2012-05-01

    Fission fragment angular distributions have been measured for 16O + 194Pt reaction forming the compound system 210Rn, in the laboratory energy range from 79 to 90 MeV. The measured fission fragment anisotropies as a function of E/VB are compared with the predictions of standard saddle point statistical model (SSPM). Anisotropies calculated using the average excitation energy and angular momentum values could not reasonably fit the experimental data. Statistical model calculations were performed using the PACE with modified fission barrier and level density parameters. Fission probability, evaporation residue cross section and neutron multiplicity were simultaneously used to fix the statistical parameters. Model calculations incorporating the chance nature of fission decay and scaled values of the rotating finite range model (RFRM) moment of inertia could reasonably fit the fragment angular anisotropies.

  15. Critical insight into the influence of the potential energy surface on fission dynamics

    International Nuclear Information System (INIS)

    Mazurek, K.; Schmitt, C.; Wieleczko, J. P.; Ademard, G.; Nadtochy, P. N.

    2011-01-01

    The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. When utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.

  16. An ionization chamber with Frisch grids for studies of high-energy neutron-induced fission

    Science.gov (United States)

    Tutin, G. A.; Ryzhov, I. V.; Eismont, V. P.; Kireev, A. V.; Condé, H.; Elmgren, K.; Olsson, N.; Renberg, P.-U.

    2001-01-01

    A gridded ionization chamber for fission fragment detection is described. The chamber has been specially designed for use at the quasi-monoenergetic 7Li(p, n) neutron source at the The Svedberg Laboratory, Uppsala, Sweden. The detector permits measurements of fission fragment energy and emission angle for two targets with diameter of up to 10 cm. The time response of the chamber (⩽5 ns FWHM) is adequate to apply time-of-flight discrimination against background events induced by non-peak neutrons. Results of angular anisotropy measurements for the 232Th (n, f) and 238U(n, f) reactions in the 20-160 MeV energy range are given.

  17. Systems Modeling For The Laser Fusion-Fission Energy (LIFE) Power Plant

    International Nuclear Information System (INIS)

    Meier, W.R.; Abbott, R.; Beach, R.; Blink, J.; Caird, J.; Erlandson, A.; Farmer, J.; Halsey, W.; Ladran, T.; Latkowski, J.; MacIntyre, A.; Miles, R.; Storm, E.

    2008-01-01

    A systems model has been developed for the Laser Inertial Fusion-Fission Energy (LIFE) power plant. It combines cost-performance scaling models for the major subsystems of the plant including the laser, inertial fusion target factory, engine (i.e., the chamber including the fission and tritium breeding blankets), energy conversion systems and balance of plant. The LIFE plant model is being used to evaluate design trade-offs and to identify high-leverage R and D. At this point, we are focused more on doing self consistent design trades and optimization as opposed to trying to predict a cost of electricity with a high degree of certainty. Key results show the advantage of large scale (>1000 MWe) plants and the importance of minimizing the cost of diodes and balance of plant cost

  18. Fission rates measured using high-energy gamma-rays from short half-life fission products in fresh and spent nuclear fuel

    International Nuclear Information System (INIS)

    Kroehnert, H.

    2011-02-01

    In recent years, higher discharge burn-ups and initial fuel enrichments have led to more and more heterogeneous core configurations in light water reactors (LWRs), especially at the beginning of cycle when fresh fuel assemblies are loaded next to highly burnt ones. As this trend is expected to continue in the future, the Paul Scherrer Institute has, in collaboration with the Swiss Association of Nuclear Utilities, swissnuclear, launched the experimental programme LIFE(at)PROTEUS. The LIFE(at)PROTEUS programme aims to better characterise interfaces between burnt and fresh UO 2 fuel assemblies in modern LWRs. Thereby, a novel experimental database is to be made available for enabling the validation of neutronics calculations of strongly heterogeneous LWR core configurations. During the programme, mixed fresh and highly burnt UO 2 fuel lattices will be investigated in the zero-power research reactor PROTEUS. One of the main types of investigations will be to irradiate the fuel in PROTEUS and measure the resulting fission rate distributions across the interface between fresh and burnt fuel zones. The measurement of fission rates in burnt fuel re-irradiated in a zero-power reactor requires, however, the development of new experimental techniques which are able to discriminate against the high intrinsic activity of the fuel. The principal goal of the present research work has been to develop such a new measurement technique. The selected approach is based on the detection of high-energy gamma-ray lines above the intrinsic background (i.e. above 2200 keV), which are emitted by short-lived fission products freshly created in the fuel. The fission products 88 Kr, 142 La, 138 Cs, 84 Br, 89 Rb, 95 Y, 90m Rb and 90 Rb, with half-lives between 2.6 min and 2.8 h, have been identified as potential candidates. During the present research work, the gamma-ray activity of short-lived fission products has, for the first time, been measured and quantitatively evaluated for re

  19. Spin observables in proton-neutron scattering at intermediate energy

    International Nuclear Information System (INIS)

    Spinka, H.

    1986-05-01

    A summary of np elastic scattering spin measurements at intermediate energy is given. Preliminary results from a LAMPF experiment to measure free neutron-proton elastic scattering spin-spin correlation parameters are presented. A longitudinally polarized proton target was used. These measurements are part of a program to determine the neutron-proton amplitudes in a model independent fashion at 500, 650, and 800 MeV. Some new proton-proton total cross sections in pure helicity states (Δσ/sub L/(pp)) near 3 GeV/c are also given. 37 refs., 2 figs

  20. Electron capture in ion-molecule collisions at intermediate energy

    International Nuclear Information System (INIS)

    Kumura, M.

    1986-01-01

    Recent progress of theoretical charge transfer study in ion-molecule collisions at the intermediate energy is reviewed. Concept of close and distant collisions obtained from extensive ion-atom collision studies is identified so that it can be utilized to model two distinct collision processes. For a close collision, explicit representation of the whole collision complex is necessary to describe collision dynamics correctly, while a model potential approach for molecule is appropriate for a distant collision. It is shown that these two distinct models are indeed capable of reproducing experimental charge transfer cross sections. Some remarks for further theoretical study of ion-molecule collisions are also given. 21 refs., 8 figs

  1. Intermediate energy semileptonic probes of the hadronic neutral current

    Energy Technology Data Exchange (ETDEWEB)

    Musolf, M.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States)]|[Old Dominion Univ., Norfolk, VA (United States). Dept. of Physics]|[CEBAF Theory Group, Newport News, VA (United States); Donnelly, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Dubach, J. [Massachusetts Univ., Amherst, MA (United States). Dept. of Physics and Astronomy; Pollock, S.J. [Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory]|[Nationaal Inst. voor Kernfysica en Hoge-Energiefysica (NIKHEF), Amsterdam (Netherlands). Sectie K; Kowalski, S. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Beise, E.J. [California Inst. of Tech., Pasadena, CA (United States). W.K. Kellogg Radiation Lab.]|[Maryland Univ., College Park, MD (United States). Dept. of Physics

    1993-06-01

    The present status and future prospects of intermediate-energy semileptonic neutral current studies are reviewed. Possibilities for using parity-violating electron scattering from nucleons and nuclei to study hadron structure and nuclear dynamics are emphasized, with particular attention paid to probes of strangeness content in the nucleon. Connections are drawn between such studies and tests of the electroweak gauge theory using electron or neutrino scattering. Outstanding theoretical issues in the interpretation of semileptonic neutral current measurements are highlighted and the prospects for undertaking parity-violating electron or neutrino scattering experiments in the near future are surveyed.

  2. Intermediate energy semileptonic probes of the hadronic neutral current

    International Nuclear Information System (INIS)

    Musolf, M.J.; Donnelly, T.W.; Dubach, J.; Beise, E.J.; Maryland Univ., College Park, MD

    1993-06-01

    The present status and future prospects of intermediate-energy semileptonic neutral current studies are reviewed. Possibilities for using parity-violating electron scattering from nucleons and nuclei to study hadron structure and nuclear dynamics are emphasized, with particular attention paid to probes of strangeness content in the nucleon. Connections are drawn between such studies and tests of the electroweak gauge theory using electron or neutrino scattering. Outstanding theoretical issues in the interpretation of semileptonic neutral current measurements are highlighted and the prospects for undertaking parity-violating electron or neutrino scattering experiments in the near future are surveyed

  3. Scaling of anisotropy flows in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Ma, Y.G.; Yan, T.Z.; Cai, X.Z.; Chen, J.G.; Fang, D.Q.; Guo, W.; Liu, G.H.; Ma, C.W.; Ma, E.J.; Shen, W.Q.; Shi, Y.; Su, Q.M.; Tian, W.D.; Wang, H.W.; Wang, K.

    2007-01-01

    Anisotropic flows (v 1 , v 2 and v 4 ) of light nuclear clusters are studied by a nucleonic transport model in intermediate energy heavy ion collisions. The number-of-nucleon scalings of the directed flow (v 1 ) and elliptic flow (v 2 ) are demonstrated for light nuclear clusters. Moreover, the ratios of v 4 /v 2 2 of nuclear clusters show a constant value of 1/2 regardless of the transverse momentum. The above phenomena can be understood by the coalescence mechanism in nucleonic level and are worthy to be explored in experiments

  4. Production of intermediate energy beams by high speed rotors

    International Nuclear Information System (INIS)

    Nutt, C.W.; Bale, T.J.; Cosgrove, P.; Kirby, M.J.

    1975-01-01

    A rotor apparatus intended for the study of gas/surface interaction processes is presently nearing completion. The carbon fiber rotors under consideration are constructed with shapes derived from long thin cylindrical rods oriented with the longest axis in a horizontal plane, and spun in a horizontal plane about an axis which is perpendicular to the long axis and passes through the mid-point of the cylinder. The beam formation processes are discussed and rotor diagrams presented. Performance of these types of high speed rotor show them to have a very important future as sources of intermediate energy molecular beams

  5. The Fukushima nuclear disaster and its effects on media framing of fission and fusion energy technologies

    OpenAIRE

    Schmidt, Luísa; Horta, Ana; Pereira, Sérgio; Delicado, Ana

    2015-01-01

    Accepted version. This paper presents results of a comparison of media coverage of fusion and fission energy technologies in three countries (Germany, Spain and Portugal) and in the English language international print media addressing transnational elite, from 2008 to 2012. The analysis showed that the accident in Fukushima in March 2010 did not have significant impact on media framing of nuclear fusion in the major part of print media under investigation. In fact, fusion is clearly disso...

  6. Fusion-fission dynamics at high excitation energies studied by neutron emission

    Science.gov (United States)

    Zank, W. P.; Hilscher, D.; Ingold, G.; Jahnke, U.; Lehmann, M.; Rossner, H.

    1986-02-01

    Neutron emission in coincidence with fusion-fission events and evaporation residues was measured in the heavy-ion reactions 141+(316 MeV) 40Ar and 175Lu+(192 MeV) 12C. Both reactions are leading to similar composite systems and excitation energies as the previously investigated reaction 165Ho+ 20Ne. In order to determine the lifetimes of the composite systems prior to scission and to study entrance channel and angular-momentum effects, the results for all three systems are compared. From measured cross sections of fission and evaporation residues, the angular momentum intervals leading to fission are deduced to be 50-109 ħ and 49-62 ħ for Pr+Ar and Lu+C, respectively. The corresponding prescission neutron multiplicities are deduced to be Mnpresc=3.6+/-0.6 and 6.3+/-0.8, whereas the respective postscission multiplicities are Mnpost=4.4+/-0.4 and 3.6+/-0.6. For the system 175Lu+ 12C it is found that 0.5+/-0.2 preequilibrium neutrons are emitted. In contrast to the evaporative neutrons, a strong anisotropy anPE=2.2+/-0.6 relative to the reaction plane defined by one fission fragment and the beam direction is observed. From the prescission neutron multiplicities, the evaporation time of the system prior to scission is deduced using the statistical model to ~=(3-12)×10-20 s. Nucleus deformation effects and neutron emission from not fully accelerated fission fragments are taken into account. The unexpected long prescission lifetimes can be explained as long transition times to the scission point caused by a large two-body viscosity. Under this assumption the viscosity parameter of the highly excited nuclei has been determined in a first approximation to μ~=0.1 TP. The results might be understood also assuming a mixture of a two-body and one-body friction.

  7. Charged particle emission from 194Hg compound nuclei: Energy and spin dependence of fission-evaporation competition

    International Nuclear Information System (INIS)

    Rajagopalan, M.; Logan, D.; Ball, J.W.; Kaplan, M.; Delagrange, H.; Rivet, M.F.; Alexander, J.M.; Vaz, L.C.; Zisman, M.S.

    1982-01-01

    Twelve reactions have been studied that produce the compound system 194 Hg* at excitation energies of 57--195 MeV and with l/sub crit/ values of 25--142h. Beams of 12 C, 19 F, 20 Ne, and 40 Ar ions in conjunction with appropriate targets have been used to measure cross sections for evaporative H/He, fission, and evaporation residues. These results confirm that most 1 H and 4 He is evaporated prior to fission or instead of fission and very little if any from the fission fragments. The probability of H/He evaporation increases dramatically with excitation energy. The evaporation residue cross sections (sigma/sub ER//πlambda-dash-bar 2 ) indicate fission survival for entrance channel l up to 27--39h. Fission survival becomes stronger and corresponding fission competition becomes weaker for excitation > or =100 MeV; a connection with charged particle emission is suggested. The dimensionless cross section for evaporation residue (sigma/sub ER//πlambda-dash-bar 2 ) depends on both the entrance channel and on energy, indicating that nonequilibrium mechanisms must play an important role, even for l< or approx. =40. Heretofore evaporation residue production has been usually thought to arise from lower partial waves while direct reactions have been thought to dominate only for the higher partial waves

  8. Ternary fission

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Since its discovery in 1946, light (charged) particle accompanied fission (ternary fission) has been extensively studied, for spontaneous as well as for induced fission reactions. The reason for this interest was twofold: the ternary particles being emitted in space and time close to the scission point were expected to supply information on the scission point configuration and the ternary fission process was an important source of helium, tritium, and hydrogen production in nuclear reactors, for which data were requested by the nuclear industry. Significant experimental progress has been realized with the advent of high-resolution detectors, powerful multiparameter data acquisition systems, and intense neutron and photon beams. As far as theory is concerned, the trajectory calculations (in which scission point parameters are deduced from the experimental observations) have been very much improved. An attempt was made to explain ternary particle emission in terms of a Plateau-Rayleigh hydrodynamical instability of a relatively long cylindrical neck or cylindrical nucleus. New results have also been obtained on the so-called open-quotes trueclose quotes ternary fission (fission in three about-equal fragments). The spontaneous emission of charged particles has also clearly been demonstrated in recent years. This chapter discusses the main characteristics of ternary fission, theoretical models, light particle emission probabilities, the dependence of the emission probabilities on experimental variables, light particle energy distributions, light particle angular distributions, correlations between light particle accompanied fission observables, open-quotes trueclose quotes ternary fission, and spontaneous emission of heavy ions. 143 refs., 18 figs., 8 tabs

  9. Intermediate evaluation of USAID/Cairo energy policy planning project

    Energy Technology Data Exchange (ETDEWEB)

    Wilbanks, T.J.; Wright, S.B. (Oak Ridge National Lab., TN (United States)); Barron, W.F. (Hong Kong Univ. (Hong Kong)); Kamel, A.M. (Ain Shams Univ., Cairo (Egypt)); Santiago, H.T. (USDOE, Washington, DC (United States))

    1992-01-01

    Three years ago, a team from the Oak Ridge National Laboratory and the Oak Ridge Associated Universities, supplemented by an expert from the US Department of Energy and a senior Egyptian energy professional, carried out what was termed an intermediate evaluation'' of a major energy policy project in Egypt. Supported by USAID/Cairo, the project had concentrated on developing and strengthening an Organization for Energy Planning (OEP) within the Government of India, and it was actually scheduled to end less than a year after this evaluation. The evaluation was submitted to USAID/Cairo and circulated elsewhere in the US Agency for International Development and the Government of Egypt as an internal report. Over the next several years, the USAID energy planning project ended and the functions performed by OEP were merged with planning capabilities in the electric power sector. Now that the major issues addressed by the evaluation report have been resolved, we are making it available to a broader audience as a contribution to the general literature on development project evaluation and institution-building.

  10. Intermediate evaluation of USAID/Cairo energy policy planning project

    Energy Technology Data Exchange (ETDEWEB)

    Wilbanks, T.J.; Wright, S.B. [Oak Ridge National Lab., TN (United States); Barron, W.F. [Hong Kong Univ. (Hong Kong); Kamel, A.M. [Ain Shams Univ., Cairo (Egypt); Santiago, H.T. [USDOE, Washington, DC (United States)

    1992-09-01

    Three years ago, a team from the Oak Ridge National Laboratory and the Oak Ridge Associated Universities, supplemented by an expert from the US Department of Energy and a senior Egyptian energy professional, carried out what was termed an ``intermediate evaluation`` of a major energy policy project in Egypt. Supported by USAID/Cairo, the project had concentrated on developing and strengthening an Organization for Energy Planning (OEP) within the Government of India, and it was actually scheduled to end less than a year after this evaluation. The evaluation was submitted to USAID/Cairo and circulated elsewhere in the US Agency for International Development and the Government of Egypt as an internal report. Over the next several years, the USAID energy planning project ended and the functions performed by OEP were merged with planning capabilities in the electric power sector. Now that the major issues addressed by the evaluation report have been resolved, we are making it available to a broader audience as a contribution to the general literature on development project evaluation and institution-building.

  11. Neutron-fragment and Neutron-neutron Correlations in Low-energy Fission

    Energy Technology Data Exchange (ETDEWEB)

    Lestone, J.P., E-mail: lestone@lanl.gov

    2016-01-15

    A computational method has been developed to simulate neutron emission from thermal-neutron induced fission of {sup 235}U and from spontaneous fission of {sup 252}Cf. Measured pre-emission mass-yield curves, average total kinetic energies and their variances, both as functions of mass split, are used to obtain a representation of the distribution of fragment velocities. Measured average neutron multiplicities as a function of mass split and their dependence on total kinetic energy are used. Simulations can be made to reproduce measured factorial moments of neutron-multiplicity distributions with only minor empirical adjustments to some experimental inputs. The neutron-emission spectra in the rest-frame of the fragments are highly constrained by ENDF/B-VII.1 prompt-fission neutron-spectra evaluations. The n-f correlation measurements of Vorobyev et al. (2010) are consistent with predictions where all neutrons are assumed to be evaporated isotropically from the rest frame of fully accelerated fragments. Measured n-f and n-n correlations of others are a little weaker than the predictions presented here. These weaker correlations could be used to infer a weak scission-neutron source. However, the effect of neutron scattering on the experimental results must be studied in detail before moving away from a null hypothesis that all neutrons are evaporated from the fragments.

  12. Energy measurement of prompt fission neutrons in 239Pu(n,f) for incident neutron energies from 1 to 200 MeV

    CERN Document Server

    Chatillon, A; Granier, Th; Laurent, B; Taïeb, J; Noda, S; Haight, R C; Devlin, M; Nelson, R O; O’Donnell, J M

    2010-01-01

    Prompt fission neutron spectra in the neutron-induced fission of 239Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Preliminary results are discussed and compared to theoretical model calculation.

  13. Evaluation of DD and DT fusion fuel cycles for different fusion-fission energy systems

    International Nuclear Information System (INIS)

    Gohar, Y.

    1980-01-01

    A study has been carried out in order to investigate the characteristics of an energy system to produce a new source of fissile fuel for existing fission reactors. The denatured fuel cycles were used because it gives additional proliferation resistance compared to other fuel cycles. DT and DD fusion drivers were examined in this study with a thorium or uranium blanket for each fusion driver. Various fuel cycles were studied for light-water and heavy-water reactors. The cost of electricity for each energy system was calculated

  14. Modelling interaction cross sections for intermediate and low energy ions

    International Nuclear Information System (INIS)

    Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.

    2002-01-01

    When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)

  15. Statistical and dynamical aspects of intermediate energy nuclear collisions

    International Nuclear Information System (INIS)

    Ghetti, R.

    1997-01-01

    Studies of intermediate energy heavy ion reactions have revealed that the probability of emitting n-fragments is reducible to the probability of emitting a single fragment through the binomial distribution. The resulting one-fragment probability shows a dependence on the thermal energy that is characteristic of statistical decay. Similarly, the charge distributions associated with n-fragment emission are reducible to the one-fragment charge distribution, and thermal scaling is observed. The reducibility equation for the n-fragment charge distribution contains a quantity with a value that starts from zero, at low transverse energies, and saturates at high transverse energies. This evolution may signal a transition from a coexistence phase to a vapour phase. In the search for a signal of liquid-gas phase transition, the appearance of intermittency is reconsidered. Percolation calculations, as well as data analysis, indicate that an intermittent-like signal appears from classes of events that do not coincide with the critical one. 232 refs

  16. Statistical and dynamical aspects of intermediate energy nuclear collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R.

    1997-01-01

    Studies of intermediate energy heavy ion reactions have revealed that the probability of emitting n-fragments is reducible to the probability of emitting a single fragment through the binomial distribution. The resulting one-fragment probability shows a dependence on the thermal energy that is characteristic of statistical decay. Similarly, the charge distributions associated with n-fragment emission are reducible to the one-fragment charge distribution, and thermal scaling is observed. The reducibility equation for the n-fragment charge distribution contains a quantity with a value that starts from zero, at low transverse energies, and saturates at high transverse energies. This evolution may signal a transition from a coexistence phase to a vapour phase. In the search for a signal of liquid-gas phase transition, the appearance of intermittency is reconsidered. Percolation calculations, as well as data analysis, indicate that an intermittent-like signal appears from classes of events that do not coincide with the critical one. 232 refs.

  17. Proceedings of the Workshop on Program Options in Intermediate-Energy Physics. Keynote address: New directions in intermediate-energy nuclear physics

    International Nuclear Information System (INIS)

    Brown, G.E.

    1980-05-01

    This report presents the keynote address given by G.E. Brown at a LASL colloquium on August 21, 1979, for the Workshop on Program Options in Intermediate-Energy Physics. Professor Brown reviewed major topics of interest in intermediate-energy nuclear physics and suggested experimental approaches that might be most productive in the near future. 22 figures

  18. Study of (p-π) reactions at intermediate energies

    International Nuclear Information System (INIS)

    Couvert, Pierre.

    1983-02-01

    This thesis presents all the A(p,π +- )A+1 experimental data measured at Saturne since 1974. A theoretical analysis of a few of them is made in the frame of a microscopic two-nucleon model, involving an intermediate δ(1232) resonance excitation. The spectrometer SPES I and the focal plane detection system are rapidly described. The data analysis method is presented in details. Calculations of the 10 B(p,π + ) 11 B (G.S.) excitation functions at constant transfer momentum lead to a good qualitative agreement in a wide range of incident energy and momentum transfer. This model also reproduces the 12 C(p,π - ) 13 O(G.S.) experimental cross sections at 613 MeV, pointing out the importance of the N(1520) resonance contribution to the (p,π - ) reaction mechanism above the (3,3) resonance [fr

  19. Hipse: an event generator for nuclear collisions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-11-01

    An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the description of nuclear collisions in the intermediate energy range is presented. Based on the sudden approximation and on geometrical hypothesis, it can conveniently simulate heavy-ion interactions at all impact parameters and thus can constitute a valuable tool for the understanding of processes such as neck emission or multifragmentation in peripheral or/and central collisions. After a detailed description of the ingredients of the model, first comparisons with experimental data collected by the INDRA collaboration are shown. Special emphasis is put on the kinematical characteristics of fragments and light particles observed at all impact parameters for Xe+Sn reactions at 25 and 50 MeV/u and Ni + Ni at 82 MeV/u. (authors)

  20. On selection rules and inelastic electron scattering at intermediate energies

    International Nuclear Information System (INIS)

    Nuroh, K.

    1986-12-01

    Correlation effects are included in the Bethe-Born theory for the generalized oscillator strength of inelastic scattering of electrons on atoms. The formulation is such as to allow for the calculation of relative line strengths of multiplets. It is used to analyze line strengths of the 4d → 4f transition in La 3+ and Ce 4+ within LS-coupling. The analysis indicates that only singlet states of the intermediate 4d 9 4f configuration are allowed. Calculated line strengths are compared with a recent core electron energy loss spectra of metallic La and tetravalent CeO 2 and there is an overall qualitative agreement between theory and experiment. (author). 11 refs, 4 figs, 2 tabs

  1. Neutronics analysis of water-cooled energy production blanket for a fusion-fission hybrid reactor

    International Nuclear Information System (INIS)

    Jiang Jieqiong; Wang Minghuang; Chen Zhong; Qiu Yuefeng; Liu Jinchao; Bai Yunqing; Chen Hongli; Hu Yanglin

    2010-01-01

    Neutronics calculations were performed to analyse the parameters of blanket energy multiplication factor (M) and tritium breeding ratio (TBR) in a fusion-fission hybrid reactor for energy production named FDS (Fusion-Driven hybrid System)-EM (Energy Multiplier) blanket. The most significant and main goal of the FDS-EM blanket is to achieve the energy gain of about 1 GWe with self-sustaining tritium, i.e. the M factor is expected to be ∼90. Four different fission materials were taken into account to evaluate M in subcritical blanket: (i) depleted uranium, (ii) natural uranium, (iii) enriched uranium, and (iv) Nuclear Waste (transuranic from 33 000 MWD/MTU PWR (Pressurized Water Reactor) and depleted uranium) oxide. These calculations and analyses were performed using nuclear data library HENDL (Hybrid Evaluated Nuclear Data Library) and a home-developed code VisualBUS. The results showed that the performance of the blanket loaded with Nuclear Waste was most attractive and it could be promising to effectively obtain tritium self-sufficiency and a high-energy multiplication.

  2. Singlet Fission

    Czech Academy of Sciences Publication Activity Database

    Smith, M. B.; Michl, Josef

    2010-01-01

    Roč. 110, č. 11 (2010), s. 6891-6936 ISSN 0009-2665 Grant - others:Department of Energy(US) DE- FG36 -08GO18017 Institutional research plan: CEZ:AV0Z40550506 Keywords : solar energy conversion * photovoltaics * singlet fission Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 33.033, year: 2010

  3. Linear free energy correlations for fission product release from the Fukushima-Daiichi nuclear accident.

    Science.gov (United States)

    Abrecht, David G; Schwantes, Jon M

    2015-03-03

    This paper extends the preliminary linear free energy correlations for radionuclide release performed by Schwantes et al., following the Fukushima-Daiichi Nuclear Power Plant accident. Through evaluations of the molar fractionations of radionuclides deposited in the soil relative to modeled radionuclide inventories, we confirm the initial source of the radionuclides to the environment to be from active reactors rather than the spent fuel pool. Linear correlations of the form In χ = −α ((ΔGrxn°(TC))/(RTC)) + β were obtained between the deposited concentrations, and the reduction potentials of the fission product oxide species using multiple reduction schemes to calculate ΔG°rxn (TC). These models allowed an estimate of the upper bound for the reactor temperatures of TC between 2015 and 2060 K, providing insight into the limiting factors to vaporization and release of fission products during the reactor accident. Estimates of the release of medium-lived fission products 90Sr, 121mSn, 147Pm, 144Ce, 152Eu, 154Eu, 155Eu, and 151Sm through atmospheric venting during the first month following the accident were obtained, indicating that large quantities of 90Sr and radioactive lanthanides were likely to remain in the damaged reactor cores.

  4. Recoil studies of photonuclear reactions at intermediate energies

    CERN Document Server

    Haba, H

    2002-01-01

    A review is given on the recoil studies of photonuclear reactions on complex nuclei at intermediate energies. Recoils of 167 radionuclides formed in the photonuclear reactions of sup 2 sup 7 Al, sup n sup a sup t V, sup n sup a sup t Cu, sup 9 sup 3 Nb, sup n sup a sup t Ag, sup n sup a sup t Ta, and sup 1 sup 9 sup 7 Au, induced by bremsstrahlung of end-point energies (E sub 0) from 600 to 1100 MeV, have been investigated by the thick-target thick-catcher method. The recoil velocity from the first step and the mean kinetic energy of the residual nuclei in the second step were deduced based on the two-step vector velocity model and discussed by comparing with the reported results on proton-induced reactions. Recoils of sup 2 sup 4 Na produced from sup 2 sup 7 Al, sup n sup a sup t V, sup n sup a sup t Cu, sup n sup a sup t Ag, and sup 1 sup 9 sup 7 Au are of special interest from a viewpoint of a change in the production mechanism with respect to target mass. Reaction yields of 58 and 63 radionuclides produce...

  5. Ionization of neon by intermediate energy carbon ions

    International Nuclear Information System (INIS)

    McLawhorn, S.L.; Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.; Dingfelder, M.; Toekesi, K.; Sulik, B.; Sigmund, P.; Schinner, A.; Reinhold, C.; Schultz, D.

    2007-01-01

    Complete text of publication follows. During the past few years there has been increasing interest in ionization of atomic and molecular targets by intermediate-energy dressed and partially dressed ions. These systems are particularly challenging to describe theoretically owing to screening of the projectile nuclear charge by bound electrons, interactions of projectile electrons with target electrons, and the large number of possible exit channels. At ECU we have initiated measurements of the doubly-differential ionization cross sections, differential in ejected electron energy and emission energy, for carbon ions of different initial charge states with atomic and molecular targets. In this presentation we compare those results with calculations being conducted at several institutions. For this presentation we will focus on electron emission from neon following interactions with carbon ions with energies from 0.067 MeV/u to 0.35 MeV/u and incident charge states from C + to C 3+ . Electron energies from 10 to 1500 eV are observed at emission angles from 20 to 120 degrees. The calculations separate the process into ionization of the target by the screened incident nucleus and the ionization of the target by the screened target nucleus. By summing these components in the rest frame of the target we can compare to the measured electron spectra. Figure 1 shows the single differential cross sections for ejection of electrons in C + -Ne collisions. Note the small contribution from ionization of the projectile. As the energy increases the contribution from projectile ionization increases; likewise as the ion energy decreases that contribution decreases. The excellent agreement shown in Figure 1 provides confidence to our use of Bohr theory for this energy range for this target. Doubly-differential cross sections based on the Classical Trajectory Monte Carlo (CTMC) techniques are compared with measurements in Fig. 2 for electron emission at 30 degrees. Again, excellent

  6. Challenging fission cross section simulation with long standing macro-microscopic model of nucleus potential energy surface

    International Nuclear Information System (INIS)

    Tamagno, Pierre

    2015-01-01

    The work presented here aims to improve models used in the fission cross section evaluation. The results give insights for a significant breakthrough in this field and yielded large extensions of the evaluation code CONRAD. Partial cross sections are inherently strongly correlated together as of the competition of the related reactions must yield the total cross section. Therefore improving fission cross section benefits to all partial cross sections. A sound framework for the simulation of competitive reactions had to be settled in order to further investigate on the fission reaction; this was implemented using the TALYS reference code as guideline. After ensuring consistency and consistency of the framework, focus was made on fission. Perspective resulting from the use of macroscopic-microscopic models such as the FRDM and FRLDM were analyzed; these models have been implemented and validated on experimental data and benchmarks. To comply with evaluation requirements in terms of computation time, several specific numerical methods have been used and parts of the program were written to run on GPU. These macroscopic-microscopic models yield potential energy surfaces that can be used to extract a one-dimensional fission barrier. This latter can then be used to obtained fission transmission coefficients that can be used in a Hauser-Feshbach model. This method has been finally tested for the calculation of the average fission cross section for 239 Pu(n,f). (author) [fr

  7. Experimental studies of pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting π 0 mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized 3 He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure

  8. Spontaneous Fission and alpha -Decay Half-Lives of Superheavy Nuclei in Different Macroscopic Energy Models

    CERN Document Server

    Lojewski, Z; Pomorski, K

    2003-01-01

    Spontaneous fission half-lives (T sub s sub f) of the heaviest nuclei are calculated in the macroscopic-microscopic approach based on the deformed Woods-Saxon potential. Four different models of the macroscopic energy are examined and their influence on the results is discussed. The calculations of (T sub s sub f) are performed within WKB approximation. Multi-dimensional dynamical-programming method (MDP) is applied to minimize the action integral in a 3-dimensional space of deformation parameters describing the nuclear shape (beta sub 2 ,beta sub 4 ,beta sub 6).

  9. The nuclear fission

    International Nuclear Information System (INIS)

    Fiorentino, J.

    1983-01-01

    The nuclear fission process considering initially the formation of compound nucleus and finishing with radioactive decay of fission products is studied. The process is divided in three parts which consist of the events associated to the nucleus of intermediate transitional state, the scission configuration, and the phenomenum of post scission. (M.C.K.) [pt

  10. The Potential Of Fission Nuclear Energy In Resolving Global Climate Change

    International Nuclear Information System (INIS)

    Pevec, D.

    2015-01-01

    There is an international consensus on the need of drastic reduction of carbon emission if very serious global climate changes are to be avoided. At present target is to limit global temperature increase to 2 Degrees of C and to keep CO 2 concentration below 450 ppm, though some recent request by climatologists argue for lower limit of 1.5 Degrees of C. The carbon emission reduction has to be done in the next few decades, as climate effects are essentially determined by integral emission. The integral emissions should not exceed 1000 Gt CO 2 to keep the probability of exceeding global temperature by 2 Degrees of C below 25 percent. Consequently, when we consider energy sources that could produce carbon free energy we have to concentrate on the period not later than 2060-2065. The sources that can take the burden of reduction in the years up to 2065 are Renewable Energy Sources (RES) and nuclear fission energy. The potential of RES has been estimated by many organizations and individuals. Their predictions indicate that RES are not likely to be sufficient to replace carbon emitters and fulfill the 2 Degrees of C limit requirements. The nuclear fission energy can give a very serious and hopefully timely (unlike nuclear fusion) contribution to reduction of emission. Even with proven conventional reactors using once through fuel cycle without fuel reprocessing the nuclear build-up in the years 2025-2065 could reach 3330 GW. With this concept nuclear contribution of 94.5 EJ/y would be reached by 2065, while integral CO 2 emission savings would be about 500 Gt CO 2 by 2065. This shows that essential nuclear contribution is possible without the use of plutonium and fast breeders, technology not ready for climate-critical next 50 years and not acceptable in present political environment. This nuclear fission energy contribution along with contributions from renewable sources, energy saving, and increased efficiency in energy use can solve the climate problems. (author).

  11. Microscopic description of fission in nobelium isotopes with the Gogny-D1M energy density functional

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Guzman, R. [Kuwait University, Physics Department, Kuwait (Kuwait); Robledo, L.M. [Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain)

    2016-11-15

    Constrained mean-field calculations, based on the Gogny-D1M energy density functional, have been carried out to describe fission in the isotopes {sup 250-260}No. The even-even isotopes have been considered within the standard Hartree-Fock-Bogoliobov (HFB) framework while for the odd-mass ones the Equal Filling Approximation (HFB-EFA) has been employed. Ground state quantum numbers and deformations, pairing energies, one-neutron separation energies, inner and outer barrier heights as well as fission isomer excitation energies are given. Fission paths, collective masses and zero-point quantum vibrational and rotational corrections are used to compute the systematic of the spontaneous fission half-lives t{sub SF} both for even-even and odd-mass nuclei. Though there exists a strong variance of the predicted fission rates with respect to the details involved in their computation, it is shown that both the specialization energy and the pairing quenching effects, taken into account within the self-consistent HFB-EFA blocking procedure, lead to larger t{sub SF} values in odd-mass nuclei as compared with their even-even neighbors. Alpha decay lifetimes have also been computed using a parametrization of the Viola-Seaborg formula. The high quality of the Gogny-D1M functional regarding nuclear masses leads to a very good reproduction of Q{sub α} values and consequently of lifetimes. (orig.)

  12. Fission and fragmentation of silver and bromine nuclei by 1-6 GeV energy photons

    International Nuclear Information System (INIS)

    Pinheiro Filho, J. de D.

    1983-01-01

    Fission and fragmentation of silver and bromine nuclei induced by bremsstrahlung photons in the maximum energy range of 1-6 GeV are studied. A special technique of nuclear emulsion for the highly ionizing nuclear fragment detection is used in the discrimination between nuclear fission and fragmentation events. Films of Ilford-KO nuclear emulsion (approximatelly 10 20 atoms/cm 2 of Ag, Br) which had been exposed to bremsstrahlung beams in 'Deutsches Elektronen Synchrotron' (DESY, Hamburg) with total doses of approximatelly 10 11 equivalent photons are used. Through a detailed analysis of range, angular and angle between fragment distributions, and empirical relations which permit to estimate nuclear fragment energy, range and velocity, the discrimination between fission and fragmentation events is made. Results related to fragment range distribution, angular distribution, distribution of angle between fragments, distribution of ratio between ranges, velocity distributions, forward/backward ratio, fission and fragmentation cross sections, nuclear fissionability and ternary fission frequency are presented and discussed. The results show that the mean photofragmentation cross section in the internal 1-6 GeV (0,09+-0,02mb) is significant when compared to the photofission (0,29+-0,05mb). It is also shown that the mean photofission cross section between 1 and 6 GeV is great by a factor of approximatelly 10 when compared to the foreseen by the cascade-evaporation nuclear model for monoenergetic photons of 0,6 GeV. (L.C.) [pt

  13. $\\gamma$-ray energy spectra and multiplicities from the neutron-induced fission of $^{235}$U using STEFF

    CERN Multimedia

    An experiment is proposed to use the STEFF spectrometer at n_TOF to study fragment $\\gamma$-correlations following the neutron-induced fission of $^{235}$U. The STEFF array of 12 NaI detectors will allow measurements of the single $\\gamma$-energy, the $\\gamma$ multiplicity, and the summed $\\gamma$energy distributions as a function of the mass and charge split, and deduced excitation energy in the fission event. These data will be used to study the origin of fission-fragment angular momenta, examining angular distribution eects as a function of incident neutron energy. The principal application of this work is in meeting the NEA high-priority request for improved $\\gamma$ray data from $^{235}$U(n; F). To improve the detection rate and expand the range of detection angles, STEFF will be modied to include two new ssion-fragment detectors each at 45 to the beam direction.

  14. Comparative evaluation of solar, fission, fusion, and fossil energy resources, part 3

    Science.gov (United States)

    Clement, J. D.; Reupke, W. A.

    1974-01-01

    The role of nuclear fission reactors in becoming an important power source in the world is discussed. The supply of fissile nuclear fuel will be severely depleted by the year 2000. With breeder reactors the world supply of uranium could last thousands of years. However, breeder reactors have problems of a large radioactive inventory and an accident potential which could present an unacceptable hazard. Although breeder reactors afford a possible solution to the energy shortage, their ultimate role will depend on demonstrated safety and acceptable risks and environmental effects. Fusion power would also be a long range, essentially permanent, solution to the world's energy problem. Fusion appears to compare favorably with breeders in safety and environmental effects. Research comparing a controlled fusion reactor with the breeder reactor in solving our long range energy needs is discussed.

  15. Fission 2009 4. International Workshop on Nuclear Fission and Fission Product Spectroscopy - Compilation of slides

    International Nuclear Information System (INIS)

    2009-01-01

    This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

  16. Laser inertial fusion-based energy: Neutronic design aspects of a hybrid fusion-fission nuclear energy system

    Science.gov (United States)

    Kramer, Kevin James

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 mum of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb 83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles having a packing fraction of 20% in 2 cm diameter fuel pebbles. The fission blanket is cooled by

  17. Formation of large target residues in intermediate energy nuclear collisions

    International Nuclear Information System (INIS)

    Loveland, W.; Aleklett, K.; Sihver, L.; Xu, Z.; Seaborg, G.T.

    1987-04-01

    We have used radiochemical techniques to measure the yields, angular distributions and velocity spectra of the large (A/sub frag/ ≥ 2/3 A/sub tgt/) target residues from the fragmentation of 197 Au by intermediate energy 12 C, 20 Ne, 32 S, 40 Ar, 84 Kr, and 139 La projectiles. The fragment moving frame angular distributions are asymmetric for the lighter projectiles (C-Ar). The fragment velocity spectra are Maxwellian for the Kr induced reactions and non-Maxwellian for the reactions induced by the lighter ions. We interpret these results in terms of a change in the dominant fragment production mechanism(s) from one(s) involving a fast non-equilibrium process for the lighter ions to a slow, equilibrium process for Kr. Comparison of the measured yields and angular distributions with calculations made using a Boltzmann transport equation with appropriate modifications for Pauli blocking, etc., show excellent agreement between data and theory. 12 refs., 12 figs

  18. Protons scattering on Li isotopes at intermediate energies

    International Nuclear Information System (INIS)

    Zhusupov, M.A.; Imambekov, O.; Sanfirova, A.V.; Ibraeva, E.T.

    2003-01-01

    The protons scattering differential cross section on the 6,7,8 Li nuclei are calculated within the framework the Glauber-Sitenko multiple scattering theory at intermediate energies (from 100 to 1000 MeV). In the calculations the multi-cluster wave functions (αt for 7 Li, αnp for 6 Li, and αtn for 8 Li) considering within potential cluster model have been used. Differential cross sections for 6 Li, 7 Li, 8 Li and 9 Li nuclei are similar: absolute cross sections are almost the same, diffraction minimum for large A shifting to the field of the least scattering angles that reflecting increase of the material radius. For the 11 Li the differential cross section absolute value is smaller about in two time than for the rest isotopes. At present it is reliably established, that the 11 Li nucleus has an exotic structure - the nine-nucleon core ( 9 Li) around which the two-neutron halo is rotating. The principal characteristics of the Li nuclei are presented in tabular form

  19. A simultaneous measurement of the angular distribution, mass and kinetic energy of uranium-235 and thorium-232 fission fragments

    Science.gov (United States)

    El-Hajje, Refaat

    2000-10-01

    Simultaneous measurements of the angular distribution, mass distribution and average total kinetic energy of fission fragments produced by the neutron-induced fission of 235U and 232Th have been made using a gridded ionisation chamber. The neutron energy range used was thermal to 1.9 MeV for 235U and 1.4 to 1.7 MeV for 232Th. The following topics were investigated: the interdependence of the fission fragment angular and mass distribution; the anomalous behaviour of fragment anisotropy for 235U(n,f) at neutron energies En below 150 keV; the possible existence of a third symmetric mass peak for 232Th(n,f); the mass fine structure in 235 U(n,f) and 232Th(n,f); and the dependence of the fission fragment average total kinetic energy on the excitation energy of the fissioning nucleus. For this study, mono-energetic neutrons were produced by the L73i( p,n)74 Be and H31( p,n)31 He reactions. Four signals produced by the fission chamber were fed into a data acquisition system and processed by a specially modified comprehensive computer program. The results indicate that there is no interdependence between the angular and mass distributions of fragments for 235U(n,f) and for 232Th(n,f). The angular distribution of 235U fission fragments showed an anisotropy of less than one for En below 150 keV. For 232Th, the expected minimum in the anisotropy near En = 1.6 MeV was confirmed. No evidence for a third peak in the mass symmetry region of 232Th(n,f) was observed, within the yield sensitivity limitation of the chamber. Fine structure was observed in the mass yield distributions for 235U(n,f) and 232Th(n,f) at mass locations predicted by theory. The fission fragment average total kinetic energy for 235U(n,f) and 232Th(n,f) showed no significant dependence on the excitation energy of the fissioning nucleus. Possible reasons for some of these results are advanced.

  20. Fission rate of nuclei at high excitation energy and emission of light particles

    International Nuclear Information System (INIS)

    Mersits, E.

    1991-10-01

    Light charged-particle emission has been measured for the reactions α + 238 U, 209 Bi, 232 Th at 118 MeV bombarding energies. The rate of particles detected in coincidence with fission fragments have been determined at high excitation energy. Modified precompound decay models and statistical models (program ALICE) have been used in an attempt to interpret the experimental data. The ratio of the level density parameter af/an was found to be 1.03 and 1.08, the temperature of neutron spectra was found to be 1.58 MeV and 1.33 MeV, for 238 U and 209 Bi, respectively. Analysing the experimental light-charged-particle spectra, there was no evidence for emission from the fission fragments which was in good agreement with calculations for the nucleus 209 Bi. On the other hand the theoretical emission spectra of 238 U predict great parts of such 'postfission' particles. Simplification in the model concerning the time of possible particle emission, that is, before the saddle-point and from the fragments, leads to the assumption of light particle emission between the saddle and the scission point

  1. Determination of the Spectral Index in the Fission Spectrum Energy Regime

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Amy Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    Neutron reaction cross sections play a vital role in tracking the production and destruction of isotopes exposed to neutron fluence. They are central to the process of reconciling the initial and final atom inventories. Measurements of irradiated samples by radiochemical methods in tangent with an algorithm are used to evaluate the fluence a sample is exposed to over the course of the irradiation. This algorithm is the Isotope Production Code (IPC) created and used by the radiochemistry data assessment team at Los Alamos National Laboratory (LANL). An integral result is calculated by varying the total neutron fluence seen by a sample. A sample, irradiated in a critical assembly, will be exposed to a unique neutron flux defined by the neutron source and distance of the sample from the source. Neutron cross sections utilized are a function of the hardness of the neutron spectrum at the location of irradiation. A spectral index is used an indicator of the hardness of the neutron spectrum. Cross sections fit forms applied in IPC are collapsed from a LANL 30-group energy structure. Several decades of research and development have been performed to formalize the current IPC cross section library. Basis of the current fission spectrum neutron reaction cross section library is rooted in critical assembly experiments performed from the 1950’s through the early 1970’s at LANL. The focus of this report is development of the spectral index used an indicator of the hardness of the neutron spectrum in the fission spectrum energy regime.

  2. Ternary fission

    Indian Academy of Sciences (India)

    the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the competition between different geometries as well as different positioning of the fragments. Also, an attempt was made to calculate the mass distribution of ternary fission process within the ...

  3. Requirements and potential development pathways for fission energy supply infrastructures of the 21st century - a systems viewpoint

    International Nuclear Information System (INIS)

    Wade, D. C.

    1999-01-01

    Using an energy supply systems approach, we envision attributes and characteristic needs of a future global fission-based energy supply infrastructure, enumerate potential pathways for meeting those needs, and identify the underlying enabling science and technology developments for R and D efforts to meet the needs

  4. Study of nuclear reactions involving heavy nuclei and intermediate- and high-energy protons and an application in nuclear reactor physics (ADS)

    International Nuclear Information System (INIS)

    Matuoka, Paula Fernanda Toledo

    2016-01-01

    In the present work, intermediate- and high-energy nuclear reactions involving heavy nuclei and protons were studied with the Monte Carlo CRISP (Rio - Ilheus - Sao Paulo Collaboration) model. The most relevant nuclear processes studied were intranuclear cascade and fission-evaporation competition. Preliminary studies showed fair agreement between CRISP model calculation and experimental data of multiplicity of evaporated neutrons (E < 20 MeV) from the p(1200 MeV) + 208 Pb reaction and of spallation residues from the p(1000 MeV) + 208 Pb reaction. The investigation of neutron multiplicity from proton-induced fission of 232 Th up to 85 MeV showed that it was being overestimated by CRISP model; on the other hand, fission cross section were being underestimated. This behavior is due to limitations of the intranuclear cascade model for low-energies (around 50 MeV). The p(1200 MeV) + 208 Pb reaction was selected for the study of a spallation neutron source. High-energy neutrons (E > 20 MeV) were emitted mostly in the intranuclear cascade stage, while evaporation presented larger neutron multiplicity. Fission cross section of 209 mb and spallation cross section of 1788 mb were calculated { both in agreement with experimental data. The fission process resulted in a symmetric mass distribution. Another Monte Carlo code, MCNP, was used for radiation transport in order to understand the role of a spallation neutron source in a ADS (Accelerator Driven System) nuclear reactor. Initially, a PWR reactor was simulated to study the isotopic compositions in spent nuclear fuel. As a rst attempt, a spallation neutron source was adapted to an industrial size nuclear reactor. The results showed no evidence of incineration of transuranic elements and modifications were suggested. (author)

  5. Systematics of neutron-induced fission cross sections over the energy range 0.1 through 15 MeV, and at 0.0253 eV

    International Nuclear Information System (INIS)

    Behrens, J.W.

    1977-01-01

    Recent studies have shown straightforward systematic behavior as a function of constant proton and neutron number for neutron-induced fission cross sections of the actinide elements in the incident-neutron energy range 3 to 5 MeV. In this report, the second in a series, fission cross-section values are studied over the MeV incident-neutron energy range, and at 0.0253 eV. Fission-barrier heights and neutron-binding energies are correlated by constant proton and neutron number; however, these systematic behaviors alone do not explain the trends observed in the fission cross-section values

  6. Electronic emission produced by light projectiles at intermediate energies

    International Nuclear Information System (INIS)

    Bernardi, G.C.

    1989-01-01

    Two aspects of the electronic emission produced by light projectiles of intermediate energies have been studied experimentally. In the first place, measurements of angular distributions in the range from θ = 0 deg -50 deg induced by collisions of 50-200 keV H + incident on He have been realized. It was found that the double differential cross section of electron emission presents a structure focussed in the forward direction and which extends up to relatively large angles. Secondly, the dependence of the double differential cross section on the projectile charge was studied using H + and He 3 2+ projectiles of 50 and 100 keV/amu incident on He. Strong deviations from a constant scaling factor were found for increasing projectile charge. The double differential cross sections and the single differential cross sections as a function of the emission angle, and the ratios of the emissions induced by He 3 2+ and H + at equal incident projectile velocities are compared with the 'Continuum Distorted Wave-Eikonal Initial State' (CDW-EIS) approximation and the 'Classical Trajectory Monte Carlo' (CTMC) method. Both approximations, in which the potential of the projectile exercises a relevant role, reproduce the general aspects of the experimental results. An electron analyzer and the corresponding projectile beam line has been designed and installed; it is characterized by a series of properties which are particularly appropriate for the study of double differential electronic emission in gaseous as well as solid targets. The design permits to assure the conditions to obtain a well localized gaseous target and avoid instrumental distortions of the measured distributions. (Author) [es

  7. Ternary Fission Studies by Correlation Measurements with Ternary Particles

    Science.gov (United States)

    Mutterer, Manfred

    2011-10-01

    The rare ternary fission process has been studied mainly by inclusive measurements of the energy distributions and fractional yields of the light charged particles (LCPs) from fission, or by experiments on the angular and energy correlation between LCPs and fission fragments (FFs). The present contribution presents a brief overview of more elaborate correlation measurements that comprise the emission of neutrons and γ rays with LCPs and FFs, or the coincident registration of two LCPs. These measurements have permitted identification of new modes of particle-accompanied fission, such as the population of excited states in LCPs, the formation of neutron-unstable nuclei as short-lived intermediate LCPs, as well as the sequential decay of particle-unstable LCPs and quaternary fission. Furthermore, the neutron multiplicity numbers bar ν (A) and distributions of fragment masses A, measured for the ternary fission modes with various LCP isotopes, give a valuable hint of the role played by nuclear shell structure in the fission process near scission. Finally, two different hitherto unknown asymmetries in ternary α-particle emission with respect to the fission axis, called the TRI and ROT effect, were studied in fission reactions induced by polarised cold neutrons.

  8. Labelling and determination of the energy in reactive intermediates in solution enabled by energy-dependent reaction selectivity

    Science.gov (United States)

    Kurouchi, Hiroaki; Singleton, Daniel A.

    2018-02-01

    Any long-lived chemical structure in solution is subject to statistical energy equilibration, so the history of any specific structure does not affect its subsequent reactions. This is not true for very short-lived intermediates because energy equilibration takes time. Here, this idea is applied to achieve the 'energy labelling' of a reactive intermediate. The selectivity of the ring-opening α-cleavage reaction of the 1-methylcyclobutoxy radical is found here to vary broadly depending on how the radical was formed. Reactions that provide little excess energy to the intermediate lead to a high selectivity in the subsequent cleavage (measured as a kinetic isotope effect), whereas reactions that provide more excess energy to the intermediate exhibit a lower selectivity. Accounting for the expected excess energy allows the prediction of the observed product ratios and, in turn, the product ratios can be used to determine the energy present in an intermediate.

  9. Primary photodissociation pathways of epichlorohydrin and analysis of the C-C bond fission channels from an O(3P)+allyl radical intermediate

    International Nuclear Information System (INIS)

    FitzPatrick, Benjamin L.; Alligood, Bridget W.; Butler, Laurie J.; Lee, Shih-Huang; Lin, Jim Jr-Min

    2010-01-01

    This study initially characterizes the primary photodissociation processes of epichlorohydrin, c-(H 2 COCH)CH 2 Cl. The three dominant photoproduct channels analyzed are c-(H 2 COCH)CH 2 +Cl, c-(H 2 COCH)+CH 2 Cl, and C 3 H 4 O+HCl. In the second channel, the c-(H 2 COCH) photofission product is a higher energy intermediate on C 2 H 3 O global potential energy surface and has a small isomerization barrier to vinoxy. The resulting highly vibrationally excited vinoxy radicals likely dissociate to give the observed signal at the mass corresponding to ketene, H 2 CCO. The final primary photodissociation pathway HCl+C 3 H 4 O evidences a recoil kinetic energy distribution similar to that of four-center HCl elimination in chlorinated alkenes, so is assigned to production of c-(H 2 COC)=CH 2 ; the epoxide product is formed with enough vibrational energy to isomerize to acrolein and dissociate. The paper then analyzes the dynamics of the C 3 H 5 O radical produced from C-Cl bond photofission. When the epoxide radical photoproduct undergoes facile ring opening, it is the radical intermediate formed in the O( 3 P)+allyl bimolecular reaction when the O atom adds to an end C atom. We focus on the HCO+C 2 H 4 and H 2 CO+C 2 H 3 product channels from this radical intermediate in this report. Analysis of the velocity distribution of the momentum-matched signals from the HCO+C 2 H 4 products at m/e=29 and 28 shows that the dissociation of the radical intermediate imparts a high relative kinetic energy, peaking near 20 kcal/mol, between the products. Similarly, the energy imparted to relative kinetic energy in the H 2 CO+C 2 H 3 product channel of the O( 3 P)+allyl radical intermediate also peaks at high-recoil kinetic energies, near 18 kcal/mol. The strongly forward-backward peaked angular distributions and the high kinetic energy release result from tangential recoil during the dissociation of highly rotationally excited nascent radicals formed photolytically in this experiment

  10. Primary photodissociation pathways of epichlorohydrin and analysis of the C-C bond fission channels from an O(3P)+allyl radical intermediate

    Science.gov (United States)

    FitzPatrick, Benjamin L.; Alligood, Bridget W.; Butler, Laurie J.; Lee, Shih-Huang; Lin, Jim-Min, Jr.

    2010-09-01

    This study initially characterizes the primary photodissociation processes of epichlorohydrin, c-(H2COCH)CH2Cl. The three dominant photoproduct channels analyzed are c-(H2COCH)CH2+Cl, c-(H2COCH)+CH2Cl, and C3H4O+HCl. In the second channel, the c-(H2COCH) photofission product is a higher energy intermediate on C2H3O global potential energy surface and has a small isomerization barrier to vinoxy. The resulting highly vibrationally excited vinoxy radicals likely dissociate to give the observed signal at the mass corresponding to ketene, H2CCO. The final primary photodissociation pathway HCl+C3H4O evidences a recoil kinetic energy distribution similar to that of four-center HCl elimination in chlorinated alkenes, so is assigned to production of c-(H2COC)=CH2; the epoxide product is formed with enough vibrational energy to isomerize to acrolein and dissociate. The paper then analyzes the dynamics of the C3H5O radical produced from C-Cl bond photofission. When the epoxide radical photoproduct undergoes facile ring opening, it is the radical intermediate formed in the O(P3)+allyl bimolecular reaction when the O atom adds to an end C atom. We focus on the HCO+C2H4 and H2CO+C2H3 product channels from this radical intermediate in this report. Analysis of the velocity distribution of the momentum-matched signals from the HCO+C2H4 products at m/e=29 and 28 shows that the dissociation of the radical intermediate imparts a high relative kinetic energy, peaking near 20 kcal/mol, between the products. Similarly, the energy imparted to relative kinetic energy in the H2CO+C2H3 product channel of the O(P3)+allyl radical intermediate also peaks at high-recoil kinetic energies, near 18 kcal/mol. The strongly forward-backward peaked angular distributions and the high kinetic energy release result from tangential recoil during the dissociation of highly rotationally excited nascent radicals formed photolytically in this experiment. The data also reveal substantial branching to an HCCH+H3

  11. Proton-carbon elastic scattering in the intermediate energy range based on the. alpha. -particle model

    Energy Technology Data Exchange (ETDEWEB)

    Li Qingrun (CCAST (World Lab.), Beijing (China) Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics); Zhou Jinli (Guangxi Normal Univ., Guilin (China). Dept. of Physics)

    1991-05-01

    The {alpha}-particle model of {sup 12}C is examined by means of proton-{sup 12}C elastic scattering in the intermediate energy range. The results show that the model gives a satisfactory account of the experimental data. The parametrized proton-{sup 4}He amplitudes in the intermediate energy region are presented. (author).

  12. Role of compound nuclei in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

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

    1988-05-01

    Hot compound nuclei are frequently produced in intermediate-energy reactions through a variety of processes. Their decay is shown to be an important and at times dominant source of complex fragments, high energy-gamma rays, and even pions

  13. Fragment Anisotropy of Complete Fusion-Fission at Subbarrier Energies for the 11B+238U and 12C+237Np Reactions

    Science.gov (United States)

    Zhang, Huanqiao; Liu, Zuhua; Xu, Jincheng; Qian, Xing; Chen, Shaolin; Lu, Lixing

    1992-06-01

    Fission fragment angular distributions have been measured for the reactions 11B+238U, 12C+237Np at near- and sub-barrier energies, and 16O+238U at 90 MeV. The complete fusion-fission and transfer-fission were separated as components in the whole energy region in this experiment. The influence of prescission neutron emission on fragment anisotropies has been considered. This effect leads to increase of the anisotropies when compared with the results obtained under the assumption of first chance fission. However, the anomalous anisotropies still persist.

  14. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f) and 252Cf(sf)

    Science.gov (United States)

    Vorobyev, A. S.; Shcherbakov, O. A.; Gagarski, A. M.; Val'Ski, G. V.; Petrov, G. A.

    2010-10-01

    A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn't depend on fragment mass and the total kinetic energy (TKE). Some minor peculiarities of angular distribution may be interpreted as a result of anisotropy of the fission neutron angular distribution in the fragment center-of-mass system.

  15. Carbon emission, energy consumption and intermediate goods trade: A regional study of East Asia

    International Nuclear Information System (INIS)

    Zhang, Jingjing

    2015-01-01

    Using country level panel data from East Asia over the period 1998–2011, this paper examines the implications of international production fragmentation-induced intermediate goods trade on the link between energy consumption and carbon pollution. The paper focuses on the interaction effect between energy consumption and trade in intermediate goods on carbon emission. The empirical results presented suggest that international trade in intermediate goods decreases the positive impact on carbon emission of energy consumption. When compared with the trade in final goods, intermediate goods trade contributes to a greater decrease in carbon pollution resulting from energy consumption. These results confirm that the link between energy consumption and carbon pollution in East Asia is significantly affected by international production fragmentation-induced trade in intermediate goods. The results presented in this paper have some important policy implications. - Highlights: • This paper tests the role of intermediates trade in energy-development nexus. • Empirical study is based on data of East Asia. • International trade can reduce the carbon pollution caused by energy use. • Intermediates trade has higher moderating effect than non-intermediate trade.

  16. Anisotropy in angular distributions of 238U fission fragments by photons, produced in high energy electron interaction with Si monocrystal

    International Nuclear Information System (INIS)

    Kasilov, V.I.; Lapin, N.N.

    1981-01-01

    An enhancement is detected under the angle of 90 deg in the fission fragment yield from 238 U nuclei produced by photons emitted by high-energy electrons passing through a silicon monocrystal. The results enable one to select the most optimal conditions to obtain maximal yields of nuclear particles [ru

  17. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f) and 252Cf(sf)

    OpenAIRE

    Val’ski G.V.; Gagarski A.M.; Shcherbakov O.A.; Vorobyev A.S.; Petrov G.A.

    2010-01-01

    A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t de...

  18. Multiplicity and energy of neutrons from {sup 233}U(n{sub th},f) fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Katsuhisa; Kimura, Itsuro; Nakagome, Yoshihiro [Kyoto Univ. (Japan)

    1998-03-01

    The correlation between fission fragments and prompt neutrons from the reaction {sup 233}U(n{sub th},f) was measured with improved accuracy. The results determined the neutron multiplicity and emission energy as a function of fragment mass and total kinetic energy. The average energy as a function of fragment mass followed a nearly symmetric distribution centered about the equal mass-split and formed a remarkable contrast with the saw-tooth distribution of the average neutron multiplicity. The neutron multiplicity from the specified fragment decreases linearly with total kinetic energy, and the slope of multiplicity with kinetic energy had the minimum value at about 130 u. The level density parameter versus mass determined from the neutron data showed a saw-tooth structure with the pronounced minimum at about 128 and generally followed the formula by Gilbert and Cameron, suggesting that the neutron emission process was very much affected by the shell-effect of the fission fragment. (author)

  19. Fission-fragment total kinetic energy and mass yields for neutron-induced fission of 235U and 238U with En =200 keV - 30 MeV

    Science.gov (United States)

    Duke, D. L.; Tovesson, F.; Brys, T.; Geppert-Kleinrath, V.; Hambsch, F.-J.; Laptev, A.; Meharchand, R.; Manning, B.; Mayorov, D.; Meierbachtol, K.; Mosby, S.; Perdue, B.; Richman, D.; Shields, D.; Vidali, M.

    2017-09-01

    The average Total Kinetic Energy (TKE) release and fission-fragment yields in neutron-induced fission of 235U and 238U was measured using a Frisch-gridded ionization chamber. These observables are important nuclear data quantites that are relevant to applications and for informing the next generation of fission models. The measurements were performed a the Los Alamos Neutron Science Center and cover En = 200 keV - 30 MeV. The double-energy (2E) method was used to determine the fission-fragment yields and two methods of correcting for prompt-neutron emission were explored. The results of this study are correlated mass and TKE data.

  20. Fission-fragment total kinetic energy and mass yields for neutron-induced fission of 235U and 238U with En =200 keV – 30 MeV

    Directory of Open Access Journals (Sweden)

    Duke D.L.

    2017-01-01

    Full Text Available The average Total Kinetic Energy (TKE release and fission-fragment yields in neutron-induced fission of 235U and 238U was measured using a Frisch-gridded ionization chamber. These observables are important nuclear data quantites that are relevant to applications and for informing the next generation of fission models. The measurements were performed a the Los Alamos Neutron Science Center and cover En = 200 keV – 30 MeV. The double-energy (2E method was used to determine the fission-fragment yields and two methods of correcting for prompt-neutron emission were explored. The results of this study are correlated mass and TKE data.

  1. Effect of the energy spectrum and angular momentum of pre-scission neutrons on the prediction of fission fragment angular anisotropy by the models

    Science.gov (United States)

    Soheyli, Saeed; Khanlari, Marzieh Varasteh

    2016-04-01

    Effects of the various neutron emission energy spectra, as well as the influence of the angular momentum of pre-scission neutrons on theoretical predictions of fission fragment angular anisotropies for several heavy-ion induced fission systems are considered. Although theoretical calculations of angular anisotropy are very sensitive to neutron emission correction, the effects of the different values of kinetic energy of emitted neutrons derived from the various neutron emission energy spectra before reaching to the saddle point on the prediction of fission fragment angular distribution by the model are not significant and can be neglected, since these effects on angular anisotropies of fission fragments for a wide range of fissility parameters and excitation energies of compound nuclei are not more than 10%. Furthermore, the theoretical prediction of fission fragment angular anisotropy is not sensitive to the angular momentum of emitted neutrons.

  2. ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

    Energy Technology Data Exchange (ETDEWEB)

    Caird, J A; Agrawal, V; Bayramian, A; Beach, R; Britten, J; Chen, D; Cross, R; Ebbers, C; Erlandson, A; Feit, M; Freitas, B; Ghosh, C; Haefner, C; Homoelle, D; Ladran, T; Latkowski, J; Molander, W; Murray, J; Rubenchik, S; Schaffers, K; Siders, C W; Stappaerts, E; Sutton, S; Telford, S; Trenholme, J; Barty, C J

    2008-10-28

    We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive.

  3. Influence of the incident particle energy on the fission product mass distribution

    International Nuclear Information System (INIS)

    Gomes, I. C.

    1998-01-01

    For 238 U targets and the five elements considered here, the best yields of neutron-rich isotopes are obtained from neutrons in the 2-20 MeV range. High energy beams of neutrons, protons, and deuterons have comparable integral yields per element to neutrons below 20 MeV, but the distributions are peaked at lower neutron numbers. This is presumably due to a higher neutron multiplicity in the pre-equilibrium stage and/or the compound nucleus/fission stage. For 235 U targets there are high yields predicted especially for thermal neutrons, and also for the fast neutron spectrum. For the high energy neutrons, protons, and deuterons 235 U has no advantage over 238 U. A detailed comparison of the relative advantages of 235 U and 238 U for radioactive beam applications is beyond the scope of this study and will be addressed in the future. The present work is the first step of a more detailed analysis of various possible one- and two-step target geometry calculated with the LAHET code system. It is intended to serve as a guide in choosing geometry and beams for future studies. It is desirable to extend this study to higher beam energies, e.g. 200 to 1000 MeV, but at this time there is very little data against which to benchmark the analysis. Additional data would also permit comparisons of isotope yields beyond the tails of the distributions presented here, to even more neutron rich isotopes

  4. Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium

    International Nuclear Information System (INIS)

    Rolfe, R.M.

    1976-12-01

    The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed

  5. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    CERN Document Server

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fujii, K; Furman, W; Goncalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Koehler, P; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mengoni, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  6. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 1: Solar energy

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    The utilization of solar energy to meet the energy needs of the U.S. is discussed. Topics discussed include: availability of solar energy, solar energy collectors, heating for houses and buildings, solar water heater, electric power generation, and ocean thermal power.

  7. Bismuth-fission detectors for high energy nucleons: I. Registration characteristics

    Czech Academy of Sciences Publication Activity Database

    Zhou, D.; Cavaioli, M.; Jain, R. K.; Spurný, František; Teodori, R.; Tommasino, L.

    1999-01-01

    Roč. 31, - (1999), s. 455-458 ISSN 1350-4487 R&D Projects: GA AV ČR IAA3048606 Keywords : Spark counter * Fission cross section * Fission fragments Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.572, year: 1999

  8. High-energy Neutron-induced Fission Cross Sections of Natural Lead and Bismuth-209

    CERN Document Server

    Tarrio, D; Carrapico, C; Eleftheriadis, C; Leeb, H; Calvino, F; Herrera-Martinez, A; Savvidis, I; Vlachoudis, V; Haas, B; Koehler, P; Vannini, G; Oshima, M; Le Naour, C; Gramegna, F; Wiescher, M; Pigni, M T; Audouin, L; Mengoni, A; Quesada, J; Becvar, F; Plag, R; Cennini, P; Mosconi, M; Rauscher, T; Couture, A; Capote, R; Sarchiapone, L; Vlastou, R; Domingo-Pardo, C; Dillmann, I; Pavlopoulos, P; Karamanis, D; Krticka, M; Jericha, E; Ferrari, A; Martinez, T; Trubert, D; Oberhummer, H; Karadimos, D; Plompen, A; Isaev, S; Terlizzi, R; Cortes, G; Cox, J; Cano-Ott, D; Pretel, C; Colonna, N; Berthoumieux, E; Vaz, P; Heil, M; Lopes, I; Lampoudis, C; Walter, S; Calviani, M; Gonzalez-Romero, E; Embid-Segura, M; Stephan, C; Igashira, M; Papachristodoulou, C; Aerts, G; Tavora, L; Berthier, B; Rudolf, G; Andrzejewski, J; Villamarin, D; Ferreira-Marques, R; Tain, J L; O'Brien, S; Reifarth, R; Kadi, Y; Neves, F; Poch, A; Kerveno, M; Rubbia, C; Lazano, M; Dahlfors, M; Wisshak, K; Salgado, J; Dridi, W; Ventura, A; Andriamonje, S; Assimakopoulos, P; Santos, C; Voss, F; Ferrant, L; Patronis, N; Chiaveri, E; Guerrero, C; Perrot, L; Vicente, M C; Lindote, A; Praena, J; Baumann, P; Kappeler, F; Rullhusen, P; Furman, W; David, S; Marrone, S; Tassan-Got, L; Gunsig, F; Alvarez-Velarde, F; Massimi, C; Mastinu, P; Pancin, J; Papadopoulos, C; Tagliente, G; Haight, R; Chepel, V; Kossionides, E; Badurek, G; Marganiec, J; Lukic, S; Pavlik, A; Goncalves, I; Duran, I; Alvarez, H; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C

    2011-01-01

    The CERN Neutron Time-Of-Flight (n\\_TOF) facility is well suited to measure small neutron-induced fission cross sections, as those of subactinides. The cross section ratios of (nat)Pb and (209)Bi relative to (235)U and (238)U were measured using PPAC detectors. The fragment coincidence method allows to unambiguously identify the fission events. The present experiment provides the first results for neutron-induced fission up to 1 GeV for (nat)Pb and (209)Bi. A good agreement with previous experimental data below 200 MeV is shown. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross section is close to 1 GeV.

  9. NEUTRON CROSS SECTION EVALUATIONS OF FISSION PRODUCTS BELOW THE FAST ENERGY REGION

    Energy Technology Data Exchange (ETDEWEB)

    OH,S.Y.; CHANG,J.; MUGHABGHAB,S.

    2000-05-11

    Neutron cross section evaluations of the fission-product isotopes, {sup 95}Mo, {sup 99}Tc, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, {sup 141}Nd, {sup 147}Sm, {sup 149}Sm, {sup 150}Sm, {sup 151}Sm, {sup 152}Sm, {sup 153}Eu, {sup 155}Gd, and {sup 157}Gd were carried out below the fast neutron energy region within the framework of the BNL-KAERI international collaboration. In the thermal energy region, the energy dependence of the various cross-sections was calculated by applying the multi-level Breit-Wigner formalism. In particular, the strong energy dependence of the coherent scattering lengths of {sup 155}Gd and {sup 157}Gd were determined and were compared with recent calculations of Lynn and Seeger. In the resonance region, the recommended resonance parameters, reported in the BNL compilation, were updated by considering resonance parameter information published in the literature since 1981. The s-wave and, if available, p-wave reduced neutron widths were analyzed in terms of the Porter-Thomas distribution to determine the average level spacings and the neutron strength functions. Average radiative widths were also calculated from measured values of resolved energy resonances. The average resonance parameters determined in this study were compared with those in the BNL and other compilations, as well as the ENDF/B-VI, JEF-2.2, and JENDL-3.2 data libraries. The unresolved capture cross sections of these isotopes, computed with the determined average resonance parameters, were compared with measurements, as well as the ENDF/B-VI evaluations. To achieve agreement with the measurements, in a few cases minor adjustments in the average resonance parameters were made. Because of astrophysical interest, the Maxwellian capture cross sections of these nuclides at a neutron temperature of 30 keV were computed and were compared with other compilations and evaluations.

  10. Evaluations of Energy Spectra of Neutrons Emitted Promptly in Neutron-induced Fission of 235U and 239Pu

    Science.gov (United States)

    Neudecker, D.; Talou, P.; Kawano, T.; Kahler, A. C.; White, M. C.; Taddeucci, T. N.; Haight, R. C.; Kiedrowski, B.; O'Donnell, J. M.; Gomez, J. A.; Kelly, K. J.; Devlin, M.; Rising, M. E.

    2018-02-01

    The energy spectra of neutrons emitted promptly in the neutron-induced fission reactions of 235U and 239Pu were re-evaluated for ENDF/B-VIII.0. These evaluations are based on a careful modeling of all relevant physics processes, an extensive analysis of experimental data and a detailed quantification of pertinent uncertainties. Energy spectra of neutrons emitted in up to fourth chance fission are considered and both compound and pre-equilibrium processes are included. Also, important nuclear model parameters, such as the average total kinetic energy of the fission fragments and the multiple chance fission probabilities, and their uncertainties are estimated based on experimental knowledge, model information and evaluated data. In addition to experimental information already available for ENDF/B-VII.1, these new evaluations make use of recently published experimental data either of high precision or spanning a broad incident energy range, information on legacy measurements explaining discrepancies and recently measured data of the average total kinetic energy as a function of incident neutron energy. The resulting evaluated data and covariances agree well with the experimental database used for the evaluation. However, the evaluated spectra are softer than the 235U and 239Pu ENDF/B-VII.1, JENDL-4.0 and JEFF-3.2 evaluations for incident neutron energies Einc ≤ 1.5 MeV and Einc ≤ 5 MeV, respectively. For Einc > 5 MeV, the evaluated spectra show structures due to the improved modeling which are not present in ENDF/B-VII.1 and JEFF-3.2 but can be observed in JENDL-4.0 evaluations. Part of these new evaluations were adopted for ENDF/B-VIII.0, while the ENDF/B-VII.1 239Pu PFNS was retained for Einc ≤ 5 MeV awaiting more conclusive experimental evidence.

  11. Compound nuclei, binary decay, and multifragmentation in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

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

    1988-07-01

    Hot compound nuclei, frequently produced in intermediate-energy reactions through a variety of processes, are shown to be an important and at times dominant source of complex fragments. 13 refs., 12 figs

  12. Detecting special nuclear materials in containers using high-energy gamma rays emitted by fission products

    Science.gov (United States)

    Norman, Eric B.; Prussin, Stanley G.

    2007-10-02

    A method and a system for detecting the presence of special nuclear materials in a container. The system and its method include irradiating the container with an energetic beam, so as to induce a fission in the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  13. Sustainable and safe nuclear fission energy technology and safety of fast and thermal nuclear reactors

    CERN Document Server

    Kessler, Günter

    2012-01-01

    Unlike existing books of nuclear reactor physics, nuclear engineering and nuclear chemical engineering this book covers a complete description and evaluation of nuclear fission power generation. It covers the whole nuclear fuel cycle, from the extraction of natural uranium from ore mines, uranium conversion and enrichment up to the fabrication of fuel elements for the cores of various types of fission reactors. This is followed by the description of the different fuel cycle options and the final storage in nuclear waste repositories. In addition the release of radioactivity under normal and possible accidental conditions is given for all parts of the nuclear fuel cycle and especially for the different fission reactor types.

  14. Fission energy program of the U.S. Department of Energy

    International Nuclear Information System (INIS)

    1978-06-01

    The document describes programs managed by the Program Director for Nuclear Energy, Department of Energy, and under the cognizance of the Committee on Science and Technology, United States House of Representatives. The major portion of the document is concerned with civilian nuclear power development, the policy for which has been established by the National Energy Plan of April 1977, but it also includes descriptions of the space applications and naval reactor programs

  15. Energy Technology Programmes 1993-1998. Intermediate report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    The Tekes energy technology research programmes were launched in 1993. The aim is to produce innovative solutions that are efficient, environmentally sound and widely - even globally - applicable. Now Tekes manages a total of 12 energy technology research programmed. Research programmed form a network linking academia and industry. Total funding for the energy technology programmed during the years 1993-1998 is estimated at some FIM 1.5 billion, about half of which will be put up by the Tekes and the rest by the industry. Funding by the Ministry of Trade and Industry covers the first full-scale applications (demonstrations) resulting from the research and development activities. Finnish technology is front-ranking in the efficient use of energy, combustion technology, renewable energy sources and environmental technology. In this report the results and the research activities of the separate programmes is presented and discussed

  16. An experimental study of the integral properties of U235 and Pu239 in an intermediate energy spectrum, and comparison with theoretical prediction

    International Nuclear Information System (INIS)

    Fox, W.N.; King, D.C.; MacBean, I.J.; Pitcher, H.H.W.; Sanders, J.E.; Small, V.G.

    1968-03-01

    Present-day methods of calculation for thermal and fast reactors involve the use of multigroup cross-section sets derived from basic nuclear data files. Since the accuracy of the calculations depends ultimately on the accuracy of these data, it is important to test them against results of 'integral experiments' in critical or sub-critical assemblies. The present report describes integral experiments designed to provide a sensitive test of the U235 and Pu239 cross-sections spectrum-averaged over the 'intermediate' energy range from about 10 eV to 10 keV. This is an area where the fissile nuclide cross-section data, particularly that for radiative capture, are still inadequately defined, as evidenced by the considerable discrepancies between various determinations. The difficulties stem from the problems of resolving and analysing the properties of closely spaced resonances and particularly in separating the fission and capture contributions. From the parameters of the resolved resonances, the distributions of the partial widths must be derived in order to provide a sound basis for the calculation of the averaged properties in the unresolved region, which constitute a significant part of the region of interest. The correct assignment of the fission and capture widths and their distributions is also necessary for the calculation of the spectrum-average capture to fission ratio (a), which has an important bearing on conversion and breeding ratios. Unlike the situation for the thermal and fast neutron regions (i.e. those below and above that considered here), where many critical and sub-critical assemblies have been made, very few integral experiments suitable for adequately testing the U235 and Pu239 data in the intermediate energy range have been reported. Hence the decision, in 1965, to undertake the work described here

  17. Interactions of quarks and gluons with nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, A.H. [Columbia Univ., New York, NY (United States)

    1994-04-01

    Some processes involving the interaction of medium energy quarks and gluons with nuclear matter are described. Possible mechanisms for the A-dependence of the energy loss of leading protons produced in proton-nucleus collisions are given, and an experiment which may help to distinguish these mechanisms is described. A possible color transparency experiment at CEBAF is described. Experiments to measure energy loss of quarks in nuclear matter and the formation time of hadrons are discussed along with the possibilities of measuring {sigma}{sub J}/{psi} and {sigma}{sub {psi}{prime}} at CEBAF.

  18. Alpha-nucleus elastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    Bonin, B.; Alamanos, N.; Berthier, B.; Bruge, G.; Faraggi, H.; Lugol, J.C.; Mittig, W.; Papineau, L.; Yavin, A.I.; Buenerd, M.; Bauhoff, W.

    1985-01-01

    Elastic scattering of 288, 340, 480 and 699 MeV Alpha-particles was measured on 208 Pb, 116 Sn and 58 Ni. The data were analysed in terms of a phenomenological optical model. The optical potentials obtained were found to vary consistently with the target nucleus and the incident energy. The radial zone where the potentials are well determined was studied in detail. The data for 208 Pb were also analysed with a folding model. The energy dependence of the strong-absorption radius and of the reaction cross section shows that the nuclear surface becomes slightly transparent for incident energies above 150 MeV per nucleon. (orig.)

  19. dd →3 Hen Reaction at Intermediate Energies

    International Nuclear Information System (INIS)

    Ladygina, N. B.

    2012-01-01

    The dd → 3 Hen reaction is considered at the energies between 200 and 520 MeV. The Alt-Grassberger-Sandhas equations are iterated up to the lowest order terms over the nucleon-nucleon t-matrix. The parameterized 3He wave function including five components is used. The angular dependence of the differential cross section and energy dependence of tensor analyzing power T 20 at the zero scattering angle are presented in comparison with the experimental data. (author)

  20. Role of near threshold resonances in intermediate energy nuclear ...

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Mayer. Plane wave. Total. On-shell Scattering. Figure 3. The squared amplitude generated using few-body equations for η-3He FSI with the input of ηN t-matrix corresponding to aηN = (0.88+i0.41) fm. Q is the excitation energy given as Q = E − MHe − Mη with E, MHe, Mη being the total energy of the η-3He ...

  1. Monte Carlo simulation for fragment mass and kinetic energy distributions from the neutron-induced fission of {sup 235}U

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, M.; Rojas, J. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima 41 (Peru); Saettone, E. [Facultad de Ciencias, Universidad Nacional de lngenieria, Av. Tupac Amaru 210, Apartado 31-139, Lima (Peru)

    2007-07-01

    The mass and kinetic energy distribution of nuclear fragments from the thermal neutron-induced fission of {sup 235}U have been studied using a Monte Carlo simulation. Besides reproducing the pronounced broadening on the standard deviation of the final fragment kinetic energy distribution ({sigma}{sub e}(m)) around the mass number m = 109, our simulation also produces a second broadening around m = 125 that is in agreement with the experimental data obtained by Belhafaf et al. These results are a consequence of the characteristics of the neutron emission, the variation in the primary fragment mean kinetic energy, and the yield as a function of the mass. (Author)

  2. On intermediate energy heavy ion optical model potential

    International Nuclear Information System (INIS)

    Rihan, T.H.; Awin, A.M.

    1992-08-01

    We derive in this paper an approximate analytical expression for the heavy ion optical potential by solving the inversion problem based on the McIntyre parametrization of the S-matrix. The quasi-classical limit of high energy approximation is modified in our approach so as to account for the Coulomb distortion of the trajectory. (author). 5 refs, 2 figs

  3. 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

  4. 1: the atom. 2: radioactivity. 3: man and radiations. 4: the energy. 5: nuclear energy: fusion and fission. 6: the operation of a nuclear reactor. 7: the nuclear fuel cycle

    International Nuclear Information System (INIS)

    2002-01-01

    This series of 7 digest booklets present the bases of the nuclear physics and of the nuclear energy: 1 - the atom (structure of matter, chemical elements and isotopes, the four fundamental interactions, nuclear physics); 2 - radioactivity (definition, origins of radioelements, applications of radioactivity); 3 - man and radiations (radiations diversity, biological effects, radioprotection, examples of radiation applications); 4 - energy (energy states, different forms of energy, characteristics); 5 - nuclear energy: fusion and fission (nuclear energy release, thermonuclear fusion, nuclear fission and chain reaction); 6 - operation of a nuclear reactor (nuclear fission, reactor components, reactor types); 7 - nuclear fuel cycle (nuclear fuel preparation, fuel consumption, reprocessing, wastes management). (J.S.)

  5. Statistical and off-equilibrium production of fragments in heavy ion collisions at intermediate energies; Production statistique et hors-equilibre de fragments dans les collisions d`ions lourdes aux energies intermediaires

    Energy Technology Data Exchange (ETDEWEB)

    Bocage, Frederic [Lab. de Physique Corpusculaire, Caen Univ., 14 - Caen (France)

    1998-12-15

    The study of reaction products, fragments and light charged particles, emitted during heavy-ion collisions at intermediate energies has shown the dominant binary dissipative character of the reaction, which is persisting for almost all impact parameters. However, in comparison with this purely binary process, an excess of nuclear matter is observed in-between the quasi-projectile and the quasi-target. To understand the mechanisms producing such an excess, this work studies more precisely the breakup in two fragments of the quasi-projectile formed in Xe+Sn, from 25 to 50 MeV/u, and Gd+C and Gd+U at 36 MeV/u. The data were obtained during the first INDRA experiment at GANIL. The angular distributions of the two fragments show the competition between statistical fission and non-equilibrated breakup of the quasi-projectile. In the second case, the two fragments are aligned along the separation axis of the two primary partners. The comparison of the fission directions and probabilities with statistical models allows us to measure the fission time, as well as the angular momentum, temperature and size of the fissioning residue. The relative velocities are compatible with Coulomb and thermal effects in the case of statistical fission and are found much higher for the breakup of a non-equilibrated quasi-projectile, which indicates that the projectile was deformed during interaction with the target. Such deformations should be compared with dynamical calculations in order to constrain the viscosity of nuclear matter and the parameters of the nucleon-nucleon interaction, (author) 148 refs., 77 figs., 11 tabs.

  6. The efficiency of counter telescopes for intermediate energy protons

    International Nuclear Information System (INIS)

    Bracco, A.; Gubler, H.P.; Hasell, D.K.; Van Oers, W.T.H.; Abegg, R.; Miller, C.A.; Stetz, A.W.

    1984-01-01

    The efficiency of counter telescopes containing a 15.2 cm thick NaI(Tl) crystal for detecting protons with energies in the range 50-350 MeV has been measured. An investigation was made of the dependence of the efficiency on the position of the proton in the counter. The results of the measurements are in close agreement with the calculations of efficiencies using available reaction cross section data. (orig.)

  7. Coherent pion photoproduction from deuterium at intermediate energies

    International Nuclear Information System (INIS)

    Osland, P.; Rej, A.K.

    1975-12-01

    The coherent photoproduction of neutral pions on deuterons is studied at energies around the (3,3) resonance and discuss the effects of the Fermi motion, rescattering and kinematical approximations. The results are very dependent upon what kinematical approximations one adopts for the impulse approximation term, which dominates up to very large angles. Allowing for this uncertainty in the kinematics, our results are in good agreement with the most recent experimental data

  8. Magnetic effects in heavy-ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    Ou Li; Li Baoan

    2011-01-01

    The time evolution and space distribution of internal electromagnetic fields in heavy-ion reactions at beam energies between 200 and 2000 MeV/nucleon are studied within an isospin-dependent Boltzmann-Uhling-Uhlenbeck transport model (ibuu11). While the magnetic field can reach about 7x10 16 G, which is significantly higher than the estimated surface magnetic field (∼1x10 15 G) of magnetars, it has almost no effect on nucleon observables because the Lorentz force is normally much weaker than the nuclear force. Very interestingly, however, the magnetic field generated by the projectilelike (targetlike) spectator has a strong focusing and defocusing effect on positive and negative pions at forward (backward) rapidities. Consequently, the differential π - /π + ratio as a function of rapidity is significantly altered by the magnetic field, whereas the total multiplicities of both positive and negative pions remain about the same. At beam energies above about 1 GeV/nucleon, while the integrated ratio of total π - to π + multiplicities is not, the differential π - /π + ratio is sensitive to the density dependence of nuclear symmetry energy E sym (ρ). Our findings suggest that magnetic effects should be carefully considered in future studies of using the differential π - /π + ratio as a probe of the E sym (ρ) at suprasaturation densities.

  9. Present status of intermediate energy data evaluation for accelerator-based transmutation of radioactive waste

    International Nuclear Information System (INIS)

    Koning, A.J.

    1994-05-01

    The recent developments in the field of nuclear data evaluation for energies above 20 MeV are outlined. As a particularly interesting application we consider accelerator-based transmutation of radioactive waste. The most urgent data needs for accelerator-based transmutation have been prioritized and translated in terms of intermediate-energy data libraries. Priorities are assigned to the materials relevant to an incineration system and to the most important associated nuclear reactions (notably reactions involving nucleons). In this contribution, the proposed actions as indicated in previous work are further discussed and a sample intermediate-energy ''starter'' data file is presented. (orig.)

  10. 1: the atom. 2: radioactivity. 3: man and radiations. 4: the energy. 5: nuclear energy: fusion and fission. 6: the operation of a nuclear reactor. 7: the nuclear fuel cycle; 1: l'atome. 2: la radioactivite. 3: l'homme et les rayonnements. 4: l'energie. 5: l'energie nucleaire: fusion et fission. 6: le fonctionnement d'un reacteur nucleaire. 7: le cycle du combustible nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This series of 7 digest booklets present the bases of the nuclear physics and of the nuclear energy: 1 - the atom (structure of matter, chemical elements and isotopes, the four fundamental interactions, nuclear physics); 2 - radioactivity (definition, origins of radioelements, applications of radioactivity); 3 - man and radiations (radiations diversity, biological effects, radioprotection, examples of radiation applications); 4 - energy (energy states, different forms of energy, characteristics); 5 - nuclear energy: fusion and fission (nuclear energy release, thermonuclear fusion, nuclear fission and chain reaction); 6 - operation of a nuclear reactor (nuclear fission, reactor components, reactor types); 7 - nuclear fuel cycle (nuclear fuel preparation, fuel consumption, reprocessing, wastes management). (J.S.)

  11. Proceedings of the fifth course of the international school of intermediate energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Bergere, R.; Costa, S.; Schaerf, C.

    1985-01-01

    This book presents the papers given at a conference on high energy physics. Topics considered at the conference included total photon absorption, scattering of photons by nuclei, pion photoproduction, nuclear structure investigations, photonuclear reactions and dispersion relations, photon spectra, quark effects, future accelerators for intermediate energy nuclear physics, bag models, polarized photons, and inelastic electron scattering.

  12. Neutron emission effects on final fragments mass and kinetic energy distribution from low energy fission of {sup 234}U

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, M.; Rojas, J. [Instituto Peruano de Energia Nuclear, Av. Canada 1470, Lima 41 (Peru); Lobato, I. [Facultad de Ciencias, Universidad Nacional de Ingenieria, Av. Tupac Amaru 210, Apartado Postal 31-139, Lima (Peru)]. e-mail: mmontoya@ipen.gob.pe

    2008-07-01

    The standard deviation of the final kinetic energy distribution ({sigma}{sub e}) as a function of mass of final fragments (m) from low energy fission of {sup 234}U, measured with the Lohengrin spectrometer by Belhafaf et al., presents a peak around m = 109 and another around m = 122. The authors attribute the first peak to the evaporation of a large number of neutrons around the corresponding mass number, i.e. there is no peak on the standard deviation of the primary kinetic energy distribution ({sigma}{sub E}) as a function of primary fragment mass (A). The second peak is attributed to a real peak on {sigma}{sub E}(A). However, theoretical calculations related to primary distributions made by H.R. Faust and Z. Bao do not suggest any peak on {sigma}{sub E}(A). In order to clarify this apparent controversy, we have made a numerical experiment in which the masses and the kinetic energy of final fragments are calculated, assuming an initial distribution of the kinetic energy without structures on the standard deviation as function of fragment mass. As a result we obtain a pronounced peak on {sigma}{sub e} (m) curve around m = 109, a depletion from m = 121 to m = 129, and an small peak around m = 122, which is not as great as that measured by Belhafaf et al. Our simulation also reproduces the experimental results on the yield of the final mass Y(m), the average number of emitted neutrons as a function of the provisional mass (calculated from the values of the final kinetic energy of the complementary fragments) and the average value of fragment kinetic energy as a function of the final mass. From our results we conclude that there are no peaks on the {sigma}{sub E} (A) curve, and the observed peaks on {sigma}{sub e} (m) are due to the emitted neutron multiplicity and the variation of the average fragment kinetic energy as a function of primary fragment mass. (Author)

  13. Assessing the role of the (n, γ f) process in the low-energy fission of actinides

    Science.gov (United States)

    Talou, Patrick; Lynn, J. E.; Kawano, T.; Mosby, S.; Couture, A.; Bouland, O.

    2016-06-01

    We review the role of the (n, γ f) process in the low-energy neutron-induced fission reaction of 239Pu. Recent measurements of the average total γ-ray energy released in this reaction were performed with the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos. Significant fluctuations of this quantity in the resonance region below 100 eV can be interpreted by invoking the presence of the indirect (n, γ f) process. Modern calculations of the probability for such an event to occur are presented.

  14. Assessing the role of the (n, γ f process in the low-energy fission of actinides

    Directory of Open Access Journals (Sweden)

    Talou Patrick

    2016-01-01

    Full Text Available We review the role of the (n, γ f process in the low-energy neutron-induced fission reaction of 239Pu. Recent measurements of the average total γ-ray energy released in this reaction were performed with the Detector for Advanced Neutron Capture Experiments (DANCE at Los Alamos. Significant fluctuations of this quantity in the resonance region below 100 eV can be interpreted by invoking the presence of the indirect (n, γ f process. Modern calculations of the probability for such an event to occur are presented.

  15. Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

    Directory of Open Access Journals (Sweden)

    K. Nishio

    2015-09-01

    Full Text Available Mass distributions of fission fragments from the compound nuclei 180Hg and 190Hg formed in fusion reactions 36Ar + 144Sm and 36Ar + 154Sm, respectively, were measured at initial excitation energies of E⁎(Hg180=33–66 MeV and E⁎(Hg190=48–71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses A¯L/A¯H=79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β+/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of A¯L/A¯H=83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.

  16. Measurement of high-energy prompt gamma-rays from neutron induced fission of U-235

    Directory of Open Access Journals (Sweden)

    Makii Hiroyuki

    2017-01-01

    Full Text Available We have developed a new setup to measure prompt γ-rays from the 235U(nth,f reaction. The setup consists of two multi-wire proportional counters (MWPCs to detect the fission fragments, two LaBr3(Ce scintillators to measure the γ-rays. The highly efficient setup was installed at the PF1B beam line of the Institut Laue Langevin (ILL. We have successfully measured the γ-ray spectrum up to about 20 MeV for the fist time in neutron-induced fission.

  17. Photoproduction of mesons on the nucleon at intermediate energies

    International Nuclear Information System (INIS)

    Guidal, M.

    1997-01-01

    In this work a model is proposed to simulate the photoproduction of pseudoscalar mesons ('PI' and K) on the nucleon at high energy. This model is based on the exchange of mesonic or baryonic Regge trajectories, it is gauge invariant and it uses a Feynman diagram formalism inspired from isobaric models. The measurements concerning the following reactions γp → nπ + , γn → pπ - , γp → pπ 0 and γn → nπ 0 are reviewed and the new model is confronted to the experimental results. The model gives a reasonable and coherent description of these 4 reactions. The model has also been applied to the photoproduction of strange mesons and of Λ and Σ baryons and has been extrapolated at low energy to the threshold of the reaction, the model matches the results even up to E γ = 2 GeV for differential cross-sections and recoil polarization. An attempt has been made to associate a Regge based description, which is valid with low transfers, with perturbative quantum chromodynamics which is valid with high transfers. The model relies on the saturation of trajectories in the high transfer region and on the counting laws that give the right variation of the cross-section. It seems that a model based on linear trajectories can be reliable up to 4 GeV. The domain of high transfer has been too little investigated to provide enough experimental data to validate the model. An experiment whose purpose is to study the photoproduction of φ at high transfer, is proposed. This experiment requires an accelerator with high useful cycle because of the smallness of the expected cross-section. The CEBAF (continuous electron beam accelerator facility) as well as the CLAS 4π detector is presented. The study of γp → pφ and γp → KΛ * (1520) requires the discrimination of kaons from pions so the measurement of 180 ps as time resolution allows the feasibility of the experiment. (A.C.)

  18. Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Arnold, Charles; Bhike, Megha; Bredeweg, Todd; Fowler, Malcolm; Krishichayan; Tonchev, Anton; Tornow, Werner; Stoyer, Mark; Vieira, David; Wilhelmy, Jerry

    2017-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations. This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Security, LLC under contract DE-AC52-06NA25396, Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and by Duke University and Triangle Universities Nuclear Laboratory through NNSA Stewardship Science Academic Alliance grant No. DE-FG52-09NA29465, DE-FG52-09NA29448 and Office of Nuclear Physics Grant No. DE-FG02-97ER41033.

  19. Spectrometry of doubly charged particles, applied to intermediate energy physics

    International Nuclear Information System (INIS)

    Oostens, Jean.

    1977-01-01

    The detection of 3 He and 4 He at GeV energies is obtained using both magnetic analysis and time-of-flight a methods, and several independent measurements of the specific ionization. This technique was applied to the extrapolation of the neutral resonance spectrum in the p + d → 3 He + X reaction and to the p- 4 He elastic scattering using incident α particles on a hydrogen target. In the first reaction, the data show the production of π 0 , eta 0 , ω 0 and eta'(957). An explanation implying a proton exchange diagram reveals the importance of the 3 He form factor. In the 4 He-p reaction, the 4 He scattered are detected in a magnetic spectrometer. It is possible to extract the elastic peaks from the continuum background corresponding to the empty target up to about 180 0 in the center of mass. The data corresponding to the backward angle reveal an increase of the cross section around 180 0 (cm). This phenomenon is qualitatively reproduced by triton exchange models. The results obtained are compared to theoretical model based on the multiple scattering phenomenon. But the interpreting of the experiments presented imply the knowledge of the wave function of both helium isotopes at momenta that have not been reached through electron scattering measurements up to now [fr

  20. Final Technical Report - Nuclear Studies with Intermediate Energy Probes

    Energy Technology Data Exchange (ETDEWEB)

    Norum, Blaine [Univ. of Virginia, Charlottesville, VA (United States)

    2017-12-14

    During the almost 20 year period of this grant research was carried out on atomic nuclei and their constituents using both photons and electrons. Research was carried out at the electron accelerator facility of the Netherlands Institute for Nuclear and High Energy Physics (NIKHEFK, Amsterdam) until the electron accelerator facility was closed in 1998. Subsequently, research was carried out at the Laser-Electron Gamma Source (LEGS) of the National Synchrotron Light Source (NSLS) located at the Brookhaven National Laboratory (BNL) until the LEGS was closed at the end of 2006. During the next several years research was carried out at both the Thomas Jefferson National Accelerator Facility (JLAB) and the High Intensity Gamma Source (HIGS) of the Tri-Universities Nuclear Laboratory (TUNL) located on the campus of Duke University. Since approximately 2010 the principal focus was on research at TUNL, although analysis of data from previous research at other facilities continued. The principal early focus of the research was on the role of pions in nuclei. This was studied by studying the production of pions using both photons (at LEGS) and electrons (at NIKHEF-K and JLAB). Measurements of charged pion photoproduction from deuterium at LEGS resulted in the most interesting result of these two decades of work. By measuring the production of a charged pion (p + ) in coincidence with an emitted photon we observed structures in the residual two-nucleon system. These indicated the existence of long-lived states not explicable by standard nuclear theory; they suggest a set of configurations not explicable in terms of a nucleon-nucleon pair. The existence of such “exotic” structures has formed the foundation for most of the work that has ensued.

  1. Reconstruction of electron energy distribution function from probe characteristics at intermediate and high pressures

    International Nuclear Information System (INIS)

    Arslanbekov, R.R.; Kolokolov, N.B.; Kudryavtsev, A.A.; Khromov, N.A.

    1991-01-01

    Kinetic theory of electron current on a probe, enabling essentially broaden the area of application of a probe method for determination of electron energy distribution function (EEDF) onto the areas of intermediate and high pressures. Method of quadrature summs makes it possible to reconstruct EEDF from integral equation for arbitrary energy dependences of diffusion parameter at any given energy interval. High efficiency of the method is demonstrated by solution of model as well as experimental tasks

  2. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    International Nuclear Information System (INIS)

    Makowitz, H.; Powell, J.R.; Wiswall, R.

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from a LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., 137 Cs, 90 Sr, 129 I, 99 Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,α), (n,γ), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R = 1.0 to 3.0) requirements. These studies also indicate that masses on the order of 1.0 g at densities of rho greater than or equal to 500.0 g/cm 3 are required for a practical fusion-based fission product transmutation system

  3. World Energy Data System (WENDS). Volume XI. Nuclear fission program summaries

    International Nuclear Information System (INIS)

    1979-06-01

    Brief management and technical summaries of nuclear fission power programs are presented for nineteen countries. The programs include the following: fuel supply, resource recovery, enrichment, fuel fabrication, light water reactors, heavy water reactors, gas cooled reactors, breeder reactors, research and test reactors, spent fuel processing, waste management, and safety and environment

  4. World Energy Data System (WENDS). Volume XI. Nuclear fission program summaries

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-01

    Brief management and technical summaries of nuclear fission power programs are presented for nineteen countries. The programs include the following: fuel supply, resource recovery, enrichment, fuel fabrication, light water reactors, heavy water reactors, gas cooled reactors, breeder reactors, research and test reactors, spent fuel processing, waste management, and safety and environment. (JWR)

  5. The measurement of intermediate mass fragments in the fermi energy domain

    International Nuclear Information System (INIS)

    Rudolf, G.

    1987-01-01

    Intermediate mass fragments in the Fermi energy domain were studied at GANIL via the Kr84 + Au reaction at 44 MeV/u. The Erel* quantity is used to study correlations between fragments. Fast-fast coincidences; fast-slow coincidences; slow-slow coincidences; and light particles are considered. Reaction mechanisms are discussed. Only qualitative analysis results are available, but they suggest that the quantitative results will be very instructive: light particle spectra will deliver source parameters (velocity, total charge, excitation energy and temperature); the multiplicity of intermediate mass fragments will be deduced from the triple coincidences between modules of XYZt detector

  6. The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C; Diaz de la Rubia, T; Moses, E

    2008-12-23

    The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission

  7. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f and 252Cf(sf

    Directory of Open Access Journals (Sweden)

    Val’ski G.V.

    2010-10-01

    Full Text Available A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t depend on fragment mass and the total kinetic energy (TKE. Some minor peculiarities of angular distribution may be interpreted as a result of anisotropy of the fission neutron angular distribution in the fragment center-of-mass system.

  8. Collective spectra along the fission barrier

    OpenAIRE

    Pigni M. T.; Andreev A. V.; Shneidman T. M.; Massimi C.; Vannini G.; Ventura A.

    2012-01-01

    Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states) and in the intermediate wells (superdeformed and hyperdeformed states) play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two–cluster co...

  9. Investigation of fusion l distributions at near and sub-barrier energies through fission fragment {gamma} ray multiplicity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, D.V.; Choudhury, R.K.; Nayak, B.K.; Nadkarni, D.M.; Kapoor, S.S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    1997-08-01

    Measurements of fission fragment gamma ray multiplicity distributions were carried out at near and sub-barrier energies in {sup 12}C, {sup 16}O + {sup 232}Th reactions. The results were analyzed to determine the average values of the total fragment spin, which were used to deduce the average spin of the compound nucleus {l_angle}l{r_angle}{sub CN}. It is observed that {l_angle}l{r_angle}{sub CN} decreases smoothly with decreasing bombarding energy and saturates as the energy falls through the barrier, thereby resembling features analogous to those predicted by various fusion models. The present results do not indicate any anomalous feature in the {l_angle}l{r_angle}{sub CN} at the sub-barrier energies, which imply that the recently observed anomalous fragment anisotropies in these systems are not due to anomalous broadening of fusion l distributions but may result from the narrowing of K distribution in the fission process. {copyright} {ital 1997} {ital The American Physical Society}

  10. Angular dependences of the tensor analyzing powers in the dd→3Hen reaction at intermediate energies

    International Nuclear Information System (INIS)

    Ladygin, V.P.; Ladygina, N.B.

    2002-01-01

    The tensor analyzing powers A yy , A xx , and A xz in the dd→ 3 Hen reaction at intermediate energies are considered in the framework of the one-nucleon-exchange approximation. Their strong sensitivity to the 3 He and deuteron spin structure at short distances is shown

  11. Intermediate steps towards the 2000-Watt society in Switzerland: an energy-economic scenario analysis

    International Nuclear Information System (INIS)

    Schulz, T. F.

    2007-01-01

    In this dissertation by Thorsten Frank Schulz the intermediate steps necessary to realise the 2000-Watt Society in Switzerland are examined. An analysis of an energy-economic scenario shows that the 2000-Watt Society should be seen as a long-term goal. According to the author, the major changes required to allow the implementation of this project concern energy-transformation and energy-demand technologies. Electricity will, according to the author, play an important role in a service-oriented society in the future. In such a transformation even intermediate steps are associated with considerable expense. The aims of the 2000-Watt Society project are listed. Energy and CO 2 balances for the domestic and transport sectors are presented and discussed. Complementary analyses are presented concerning fuel cells and wood-based fuel technologies. Finally, the implications of the 2000-Watt society and the effects of technological change are summarised and an outlook is presented

  12. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    International Nuclear Information System (INIS)

    Makowitz, H.; Powell, J.R.; Wiswall, R.

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from an LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., 137 Cs, 90 Sr, 129 I, 99 Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,α), (n,γ), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R=1.0 to 3.0) requirements

  13. Pair production by photons. Screening corrections for intermediate and high energies

    International Nuclear Information System (INIS)

    Oeverboe, I.

    1978-01-01

    The screening correction to the total cross-section for coherent electron pair production by photons is evaluated for intermediate and high energies, by employing the Born-approximation recoil momentum distribution and accurate relativistic form factors. Results are given for all 3<=Z<=92. For each element the results are presented in terms of a seven-parameter formula which is based on a high-energy expansion of the screened cross-section. (author)

  14. Effects of Neutron Emission on Fragment Mass and Kinetic Energy Distribution from Thermal Neutron-Induced Fission of 235U

    International Nuclear Information System (INIS)

    Montoya, M.; Rojas, J.; Saetone, E.

    2007-01-01

    The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of 235 U(n th ,f) have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions

  15. The nuclear fission process

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Fifty years after its discovery, the nuclear fission phenomenon is of recurring interest. When its fundamental physics aspects are considered, fission is viewed in a very positive way, which is reflected in the great interest generated by the meetings and large conferences organized for the 50th anniversary of its discovery. From a purely scientific and practical point of view, a new book devoted to the (low energy) nuclear fission phenomenon was highly desirable considering the tremendous amount of new results obtained since the publication of the book Nuclear Fission by Vandenbosch and Huizenga in 1973 (Academic Press). These new results could be obtained thanks to the growth of technology, which enabled the construction of powerful new neutron sources, particle and heavy ion accelerators, and very performant data-acquisition and computer systems. The re-invention of the ionization chamber, the development of large fission fragment spectrometers and sophisticated multiparameter devices, and the production of exotic isotopes also contributed significantly to an improved understanding of nuclear fission. This book is written at a level to introduce graduate students to the exciting subject of nuclear fission. The very complete list of references following each chapter also makes the book very useful for scientists, especially nuclear physicists. The book has 12 chapters covering the fission barrier and the various processes leading to fission as well as the characteristics of the various fission reaction products. In order to guarantee adequate treatment of the very specialized research fields covered, several distinguished scientists actively involved in some of these fields were invited to contribute their expertise as authors or co-authors of the different chapters

  16. Validation of the fission yield and decay data libraries with the 10 s-delayed 235 U fission γ-ray energy spectrum

    Science.gov (United States)

    Mendoza, E.; Álvarez-Velarde, F.; Bécares, V.; Cano-Ott, D.; González-Romero, E.; Martínez, T.; Villamarín, D.

    2017-10-01

    We have measured with a LaCl3 detector the γ-ray spectrum emitted by a 235 U enriched UO2 fuel rod 10 s after being irradiated with thermal neutrons. The experimental results are compared with simulations performed with the fission product yield and radioactive decay data libraries present in the most recent releases of ENDF/B, JEFF and JENDL.

  17. An analytic solution for energy loss and time-of-flight calculations for intermediate-energy light ions

    NARCIS (Netherlands)

    Snellings, RJM; Hulsbergen, W; Prendergast, EP; van den Brink, A; de Haas, AP; Habets, JJLM; Kamermans, R; Koopmans, M; Kuijer, PG; de Laat, CTAM; Ostendorf, RW; Peghaire, A; Rossewij, M

    1999-01-01

    Particle identification in intermediate heavy-ion collisions, using a modern 4 pi detector which contains several active layers, relies on a parametrisation or numerical integration of the energy loss in thick layers of detector material for different ions. Here an analytical solution applicable

  18. MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Mashnik, Stepan Georgievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kerby, Leslie Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Idaho, Moscow, ID (United States)

    2015-08-24

    Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.

  19. What can one learn about lithium breakup from the fission reaction of {sup 232}Th({sup 6}Li, f) at energies around the Coulomb barrier?

    Energy Technology Data Exchange (ETDEWEB)

    Itkis, I.M. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)]. E-mail: juliami@mail.ru; Bogachev, A.A. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Chizhov, A.Yu. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Gorodisskiy, D.M. [Institute of Nuclear Physics, National Nuclear Center, 480082 Almaty (Kazakhstan); Itkis, M.G. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Knyazheva, G.N. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Kondratiev, N.A. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Kozulin, E.M. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Krupa, L. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Mulgin, S.I. [Institute of Nuclear Physics, National Nuclear Center, 480082 Almaty (Kazakhstan); Pokrovsky, I.V.; Prokhorova, E.V. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Rusanov, A.Ya. [Institute of Nuclear Physics, National Nuclear Center, 480082 Almaty (Kazakhstan); Voskressenski, V.M. [Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Zhdanov, S.V. [Institute of Nuclear Physics, National Nuclear Center, 480082 Almaty (Kazakhstan)

    2006-08-31

    Fission fragment mass and energy distributions (MED) and fission fragment folding angle distributions (FFFAD) have been measured in the reaction {sup 6}Li+{sup 232}Th within the lithium projectile energy range E{sub lab}=28.5-62.5 MeV. The values of the ratio between the complete and incomplete fusion cross-sections have been obtained from a combined analysis of MED and FFFAD. The incomplete fusion originates from transfer reactions and/or from the {sup 6}Li breakup mainly into {alpha} and d clusters. It has been found that the contribution of complete fusion into the total fusion-fission cross-section is only {approx}27% at the lithium projectile energy E{sub lab}=28.5 MeV ({approx}2 MeV below the Coulomb barrier)

  20. The structure of nuclear states at low, intermediate and high excitation energies

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1976-01-01

    It is shown that within the model based on the quasiparticle-phonon interaction one can obtain the description of few-quasiparticle components of nuclear states at low, intermediate and high excitation energies. For the low-lying states the energy of each level is calculated. The few-quasiparticle components at intermediate and high excitation energies are represented to be averaged in certain energy intervals and their characteri stics are given as the corresponding strength functions. The fragmentation of single-particle states in deformed nuclei is studied. It is shown that in the distribution of the single-particle strength alongside with a large maximum there appear local maxima and the distribution itself has a long tail. The dependence of neutron strength functions on the excitation energy is investigated for the transfer reaction of the type (d,p) and (d,t). The s,- p,- and d-wave neutron strength functions are calculated at the neutron binding energy Bn. A satisfactory agreement with experiment is obtained. The energies and Elambda-strength functions for giant multipole resonances in deformed nuclei are calculated. The energies of giant quadrupole and octupole resonances are calculated. Their widths and fine structure are being studied. It is stated that to study the structure of highly excited states it is necessary to find the values of many-quasiparticle components of the wave functions. The ways of experimental determination of these components based on the study of γ-transitions between highly excited states are discussed

  1. Radiochemistry and the Study of Fission

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-14

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  2. Radiochemistry and the Study of Fission

    International Nuclear Information System (INIS)

    Rundberg, Robert S.

    2016-01-01

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  3. Neutron Transport and Nuclear Burnup Analysis for the Laser Inertial Confinement Fusion-Fission Energy (LIFE) Engine

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, K J; Latkowski, J F; Abbott, R P; Boyd, J K; Powers, J J; Seifried, J E

    2008-10-24

    Lawrence Livermore National Laboratory is currently developing a hybrid fusion-fission nuclear energy system, called LIFE, to generate power and burn nuclear waste. We utilize inertial confinement fusion to drive a subcritical fission blanket surrounding the fusion chamber. It is composed of TRISO-based fuel cooled by the molten salt flibe. Low-yield (37.5 MJ) targets and a repetition rate of 13.3 Hz produce a 500 MW fusion source that is coupled to the subcritical blanket, which provides an additional gain of 4-8, depending on the fuel. In the present work, we describe the neutron transport and nuclear burnup analysis. We utilize standard analysis tools including, the Monte Carlo N-Particle (MCNP) transport code, ORIGEN2 and Monteburns to perform the nuclear design. These analyses focus primarily on a fuel composed of depleted uranium not requiring chemical reprocessing or enrichment. However, other fuels such as weapons grade plutonium and highly-enriched uranium are also under consideration. In addition, we have developed a methodology using {sup 6}Li as a burnable poison to replace the tritium burned in the fusion targets and to maintain constant power over the lifetime of the engine. The results from depleted uranium analyses suggest up to 99% burnup of actinides is attainable while maintaining full power at 2GW for more than five decades.

  4. Selected problems in experimental intermediate energy physics. Final technical report, February 1, 1991--January 31, 1994

    International Nuclear Information System (INIS)

    Mayes, B.W.; Hungerford, E.V.; Pinsky, L.S.

    1997-01-01

    A complete description of the research program of the intermediate energy group at the University of Houston may be found in previous progress reports, renewal proposals, and proposals to various accelerator advisory committees. The summaries of activities are presented in the next section. The objectives of the research program are to: (1) investigate selected, forefront problems in experimental intermediate energy physics; (2) educate students in this field of research; and (3) develop the instrumentation necessary to undertake this experimental program. There were three major thrusts of the program: (1) strange particle physics, where a strange quark is embedded in the nuclear medium; (2) muon electro-weak decay, which involves a search for a violation of the standard model of the electro-weak interaction; and (3) measurement of the spin dependent structure function of the neutron and proton

  5. Degree of Rate Control: How Much the Energies of Intermediates and Transition States Control Rates

    DEFF Research Database (Denmark)

    Stegelmann, Carsten; Andreasen, Anders; Campbell, Charles T.

    2009-01-01

    recently introduced, via the “degree of rate control” of elementary steps. By extending that idea, we argue that even more useful than identifying the rate-determining step is identifying the rate-controlling transition states and the rate-controlling intermediates. These identify a few distinct chemical...... electronic or steric control on the relative energies of the key species. Since these key species are the ones whose relative energies most strongly influence the net reaction rate, they also identify the species whose energetics must be most accurately measured or calculated to achieve an accurate kinetic...... model for any reaction mechanism. Thus, it is very important to identify these rate-controlling transition states and rate-controlling intermediates for both applied and basic research. Here, we present a method for doing that....

  6. (Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions)

    Energy Technology Data Exchange (ETDEWEB)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

  7. Supplement to the report of the Expert Committee 'Intermediate-Energy Physics' 1986-1988/89

    International Nuclear Information System (INIS)

    1990-02-01

    In the supplement to the scientitic report of the sponsoring project of the Federal Ministery for Research and Technology 'Intermediate-Energy Physics' the publications are collected, which have come out in the three years of the sponsoring in the single projects. Essentially only journal articles were taken up, in order to keep the extent of this list surveyable. On the taking up of the manifold of dissertations, diploma theses, and talks generally was abandoned. (orig.) [de

  8. Nuclear structure at intermediate energies: Progress report, January 1-December 31, 1988

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1988-01-01

    This report discusses the progress in the following experiments: Λ Spin Transfer Experiment; Σ 0 Spin Transfer Experiment; Strangeness Production in Heavy Ion Collisions; Measurement of the Imaginary Part of the I=1 /bar N/N S-Wave Scattering Length; Single Pion Production in np Scattering; Measurements of the π + d→Δ ++ n at Intermediate Energy; and PhotoJets from Nuclei

  9. Elastic scattering of intermediate energy kaons from nuclei and its Coulomb effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhenqiu; Kong Lingjiang; Liu Xianhui

    1986-04-01

    In the frame of the eikonal multiple scattering theory, using the basic parameters which are given by the different authors, the elastic scattering of the intermediate energy kaon mesons on /sup 12/C and /sup 40/Ca is studied. The Coulomb effect is calculated too. The results are in agreement with the experimental data. The Coulomb effect not only enhances the small angle differential cross section, but also fills up the dip of the differential cross section.

  10. Asymmetry ratio in pair production and the degree of linearly polarized photons at intermediate energies

    CERN Document Server

    Asai, J

    1999-01-01

    In order to initiate the experiments using linearly polarized tagged photons at intermediate energies, it is imperative to know and to monitor the degree of polarization. The relationship is re-examined between the linear polarization of photons and the asymmetry ratio in pair production by such photons. An improved method is proposed in which pairs are prohibited from entering the cone region around the incident photon beam. By restricting the directions of pairs, the asymmetry ratio is much improved. (author)

  11. Binary and ternary fission yields induced by 12C and 20Ne ions on 238U targets

    International Nuclear Information System (INIS)

    Otto, R.J.

    1974-01-01

    Evidence for ternary fission of 250 Cf* and 258 No* compound nuclei has been found. Relative cross section data for nuclides with masses between 24 Na and 161 Tb have been determined for 12 C bombardments of natural uranium at laboratory energies of 122 MeV, 113 MeV and 105 MeV. Relative cross section data for 8 nuclides between 24 Na and 66 Ni were sought for 20 Ne bombardments of natural uranium at 150 MeV laboratory energies. The binary fission fragment mass distribution for 238 U( 12 C,f) was determined by analysis of fission fragment recoil collection foils using radiochemical techniques and high resolution gamma ray spectroscopy. The results indicated the existence of a ternary fission branch similar to mass distributions obtained for He induced fission of Th, U, and Pu nuclei at intermediate energies. Comparison of the data with He induced ternary fission data obtained previously in this laboratory indicated an increase in the ternary fission probability with increasing Z 2 /A of the compound nucleus and with excitation energy. A shift of the binary-ternary fission product intersection point to lower mass numbers with increasing Z 2 /A and excitation energy of the compound nucleus was also observed. (Diss. Abstr. Int., B)

  12. Contribution to the study of nuclear fission

    International Nuclear Information System (INIS)

    Serot, O.

    2009-09-01

    The author proposes an overview of his research activity during the past fifteen years and more particularly that dealing with nuclear fission. The first part reports works on nucleus physics at the scission via the investigation of ternary fission (experimental procedure, influence of fission modes, influence of resonance spin, influence of excitation energy of the fissioning nucleus, emission probabilities, energy spectra of ternary alphas and tritons, emission mechanism). The second part reports measurements and assessments of neutron-induced fission cross sections. The third part reports the investigation of some properties of fission products (efficiencies, branching ratios of the main delayed neutron precursors)

  13. The 2-ID-B intermediate-energy scanning X-ray microscope at the APS

    International Nuclear Information System (INIS)

    McNulty, I.; Paterson, D.; Arko, J.; Erdmann, M.; Goetze, K.; Ilinski, P.; Mooney, T.; Vogt, S.; Xu, S.; Frigo, S.P.; Stampfl, A.P.J.; Wang, Y.

    2002-01-01

    The intermediate-energy scanning x-ray microscope at beamline 2-ID-B at the Advanced Photon Source is a dedicated instrument for materials and biological research. The microscope uses a zone plate lens to focus coherent 1-4 keV x-rays to a 60 nm focal spot of 10 9 photons/s onto the sample. It records simultaneous transmission and energy-resolved fluorescence images. We have used the microscope for nano-tomography of chips and micro-spectroscopy of cells. (authors)

  14. Intermediate energy proton stopping power for hydrogen molecules and monoatomic helium gas

    Science.gov (United States)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, J. W.

    1984-01-01

    Stopping power in the intermediate energy region (100 keV to 1 MeV) was investigated, based on the work of Lindhard and Winther, and on the local plasma model. The theory is applied to calculate stopping power of hydrogen molecules and helium gas for protons of energy ranging from 100 keV to 2.5 MeV. Agreement with the experimental data is found to be within 10 percent. Previously announced in STAR as N84-16955

  15. Reconstruction of the electron energy distribution function from probe characteristics at intermediate and high pressures

    International Nuclear Information System (INIS)

    Arslanbekov, R.R.; Kolokolov, N.B.; Kudryavtsev, A.A.; Khromov, N.A.

    1991-01-01

    Gorbunov et al. have developed a kinetic theory of the electron current drawn by a probe, which substantially extends the region of applicability of the probe method for determining the electron energy distribution function, enabling probes to be used for intermediate and high pressures (up to p ≤ 0.5 atm for monatomic gases). They showed that for λ var-epsilon >> a + d (where a is the probe radius, d is the sheath thickness, and λ var-epsilon is the electron energy relaxation length) the current density j e (V) drawn by the probe is related to the unperturbed distribution function by an integral equation involving the distribution function. The kernal of the integral equation can be written as a function of the diffusion parameter. In the present paper the method of quadrature sums is employed in order to obtain the electron energy distribution function from probe characteristics at intermediate and high pressures. This technique enables them to recover the distribution function from the integral equation when the diffusion parameter has an arbitrary energy dependence ψ 0 (var-epsilon) in any given energy range. The effectiveness of the method is demonstrated by application to both model problems and experimental data

  16. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Tso, Kin [Univ. of California, Berkeley, CA (United States)

    1996-05-01

    The 129Xe-induced reactions on natCu, 89Y, 165Ho, and 197Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.

  17. 242Pu neutron-induced fission cross-section measurement from 1 to 2 MeV neutron energy

    Science.gov (United States)

    Marini, P.; Mathieu, L.; Aïche, M.; Belier, G.; Czajkowski, S.; Ducasse, Q.; Jurado, B.; Kessedjian, G.; Matarranz, J.; Plompen, A.; Salvador-Castiñeira, P.; Taieb, J.; Tsekhanovich, I.

    2017-11-01

    Relative values of the neutron-induced fission cross section σ (n ,f ) of 242Pu have been measured with respect to the standard 1H(n ,p ) elastic scattering cross section, at average energies of 1.0, 1.4, and 1.9 MeV . The measurements are part of an international effort to reduce uncertainties and provide independent nuclear data relevant for fast-spectrum reactors. The shape of the measured cross section is in good agreement with data from Tovesson et al. [Phys. Rev. C 79, 014613 (2009), 10.1103/PhysRevC.79.014613] and with the most recent data from Matei et al. [Phys. Rev. C 95, 024606 (2017), 10.1103/PhysRevC.95.024606], but disagrees with the shapes of ENDF/B-VII.1 and JEFF3.2 evaluations. Absolute values of σ (n ,f ) , obtained under some assumptions, indicate an overestimation of σ (n ,f ) in the evaluated libraries at 1.0 and 1.4 MeV , while a good agreement is found with ENDF/B-VII.1 at 1.9 MeV . A careful analysis of the impact of scattered neutrons and anisotropy of the fission fragment angular distribution has been performed. The measurement of the neutron flux by means of a proton-recoil detector is discussed. A comprehensive study of corrections applied to the data, of associated uncertainties, and of correlations between the measurements at the different energies is presented.

  18. GGA+U study of uranium mononitride: A comparison of the U-ramping and occupation matrix schemes and incorporation energies of fission products

    Energy Technology Data Exchange (ETDEWEB)

    Claisse, Antoine, E-mail: claisse@kth.se [KTH Royal Institute of Technology, Reactor Physics, AlbaNova University Centre, 106 91 Stockholm (Sweden); Klipfel, Marco [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Lindbom, Niclas [KTH Royal Institute of Technology, Reactor Physics, AlbaNova University Centre, 106 91 Stockholm (Sweden); Freyss, Michel [CEA, DEN, DEC, Centre de Cadarache, 13108 Saint-Paul-lez-Durance (France); Olsson, Pär [KTH Royal Institute of Technology, Reactor Physics, AlbaNova University Centre, 106 91 Stockholm (Sweden)

    2016-09-15

    Uranium mononitride is studied in the DFT + U framework. Its ground state is investigated and a study of the incorporation of diverse fission products in the crystal is conducted. The U-ramping and occupation matrix control (OMC) schemes are used to eliminate metastable states. Beyond a certain amount of introduced correlation, the OMC scheme starts to find a lower total energy. The OMC scheme is chosen for the second part of this study. Furthermore, the influence of the magnetic ordering is studied using the U-ramping method, showing that antiferromagnetic order is the most stable one when the U parameter is larger than 1.75 eV. The effect on the density of states is investigated and elastic constants are provided for comparison with other methods and experiments. The incorporation energies of fission products in different defect configurations are calculated and these energies are corrected to take into account the limited size of the supercell. - Highlights: • We studied bulk uranium nitride with means of DFT+U with the U-ramping scheme and the OMC scheme. • We produces a density of states plot and calculated the elastic constants of UN. • We calculated the incorporation energy of many fission products in UN, and corrected them to take into account the elastic interactions. • The OMC scheme should be used over the U-ramping scheme. • Fission products go to larger crystal sites.

  19. Neutron emission effects on fragment mass and kinetic energy distribution from fission of 239Pu induced by thermal neutrons

    International Nuclear Information System (INIS)

    Montoya, M.; Rojas, J.; Lobato, I.

    2010-01-01

    The average of fragment kinetic energy (E-bar sign*) and the multiplicity of prompt neutrons (ν(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y(m*)) from thermal neutron-induced fission of 239 Pu have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation σ E *(m*). In this work we have made a numerical simulation of that experiment which reproduces its results, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass (σ E (A)). As a result of the simulation we obtain the dependence σ E *(m*) which presents an enhancement between m* = 92 and m* = 110, and a peak at m* = 121.

  20. Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martovetsky, N. N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Molvik, A. W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simonen, T. C. [Univ. of California, Berkeley, CA (United States)

    2011-05-13

    The achieved performance of the gas dynamic trap version of magnetic mirrors and today’s technology we believe are sufficient with modest further efforts for a neutron source for material testing (Q=Pfusion/Pinput~0.1). The performance needed for commercial power production requires considerable further advances to achieve the necessary high Q>>10. An early application of the mirror, requiring intermediate performance and intermediate values of Q~1 are the hybrid applications. The Axisymmetric Mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of the natural divertors in the form of end tanks. This level of physics performance has the virtue of low risk and only modest R&D needed and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~ 80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. Simple circular superconducting coils are based on today’s technology. The positive ion neutral beams are similar to existing units but designed for steady state. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, microstability of sloshing ions. Burning fission reactor wastes by fissioning actinides (transuranics: Pu, Np, Am, Cm, .. or just minor actinides: Np, Am, Cm, …) in the hybrid will multiply fusion’s energy by a factor of ~10 or more and diminish the Q needed to less than 1 to overcome the cost of recirculating power for good economics. The economic value of destroying actinides by fissioning is rather low based on either the cost of long-term storage or even deep geologic disposal so most of the revenues of hybrids will come from electrical power. Hybrids that obtain revenues from

  1. Tip model of cold fission

    International Nuclear Information System (INIS)

    Goennenwein, F.; Boersig, B.

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)

  2. Nuclear Forensics and Radiochemistry: Fission

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-11-07

    Radiochemistry has been used to study fission since it’ discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution.

  3. Fission fragment angular momentum

    International Nuclear Information System (INIS)

    Frenne, D. De

    1991-01-01

    Most of the energy released in fission is converted into translational kinetic energy of the fragments. The remaining excitation energy will be distributed among neutrons and gammas. An important parameter characterizing the scission configuration is the primary angular momentum of the nascent fragments. Neutron emission is not expected to decrease the spin of the fragments by more than one unit of angular momentum and is as such of less importance in the determination of the initial fragment spins. Gamma emission is a suitable tool in studying initial fragment spins because the emission time, number, energy, and multipolarity of the gammas strongly depend on the value of the primary angular momentum. The main conclusions of experiments on gamma emission were that the initial angular momentum of the fragments is large compared to the ground state spin and oriented perpendicular to the fission axis. Most of the recent information concerning initial fragment spin distributions comes from the measurement of isomeric ratios for isomeric pairs produced in fission. Although in nearly every mass chain isomers are known, only a small number are suitable for initial fission fragment spin studies. Yield and half-life considerations strongly limit the number of candidates. This has the advantage that the behavior of a specific isomeric pair can be investigated for a number of fissioning systems at different excitation energies of the fragments and fissioning nuclei. Because most of the recent information on primary angular momenta comes from measurements of isomeric ratios, the global deexcitation process of the fragments and the calculation of the initial fragment spin distribution from measured isomeric ratios are discussed here. The most important results on primary angular momentum determinations are reviewed and some theoretical approaches are given. 45 refs., 7 figs., 2 tabs

  4. [Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions

    International Nuclear Information System (INIS)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy ( 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ''best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon 129 Xe with 197 Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon 12 C with 197 Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated

  5. Proceedings of the LAMPF workshop on photon and neutral meson physics at intermediate energies

    International Nuclear Information System (INIS)

    Baer, H.W.; Crannell, H.; Peterson, R.J.

    1987-12-01

    This volume contains the Proceedings of the Workshop on ''Photon and Neutral-Meson, Physics at Intermediate Energies,'' held at Los Alamos, New Mexico, January 7 to 9, 1987. The purpose of this workshop was to bring together scientists working in the areas of electromagnetic, heavy-ion, and light hadron physics to discuss both the physics that could be addressed and potential capabilities of new, large intermediate-energy photon detectors. Based on the papers contained in these proceedings, it appears clear that there are a number of important areas that could be addressed with a much higher resolution neutral meson detector. It is also clear that the technical capability for building a neutral meson detector for energies up to 4 GeV with solid angle of approximately 10 mrs and resolution of a few hundred keV now exists. It also appears entirely reasonable to construct such a detector to be easily transportable so that it would become a national facility, available for use at a number of different laboratories. From the many interesting papers presented and from the broad representation of physicists from laboratories in Asia, Canada, Europe, Japan, and the United States, there appears to be a strong case for proceeding with the construction of such a detector

  6. A liquid 3He target system for use at intermediate energies

    International Nuclear Information System (INIS)

    Hasell, D.K.; Abegg, R.; Murdoch, B.T.; Van Oers, W.T.H.; Postma, H.; Soukup, J.

    1981-01-01

    A liquid 3 He target system, with remote instrumentation and handling capabilities, has been developed for experiments using the 180-525 MeV TRIUMF cyclotron. 3 He gas is liquified, by means of a 4 He cryostat, into a cylindrical target cell (4.4 cm diameter, 1.6 cm thick) and maintained during operation at approx. equal to1.6 K. This provides an areal target density of approx. equal to2.7 x 10 22 3 He nuclei/cm 2 (128 mg/cm 2 ), suitable for intermediate energy proton scattering. (orig.)

  7. Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu, Jun; Li, Bao-An

    2013-01-01

    Incorporating for the first time both the spin and isospin degrees of freedom explicitly in transport model simulations of intermediate-energy heavy-ion collisions, we observe that a local spin polarization appears during collision process. Most interestingly, it is found that the nucleon spin up–down differential transverse flow is a sensitive probe of the spin–orbit interaction, providing a novel approach to probe both the density and isospin dependence of the in-medium spin–orbit coupling that is important for understanding the structure of rare isotopes and synthesis of superheavy elements

  8. Production of nuclei far from the beta stability line using intermediate-energy heavy ions

    International Nuclear Information System (INIS)

    Guerreau, D.

    1986-05-01

    The production of far unstable nuclei using heavy ion accelerators in the intermediate energy domain is reviewed. The various mechanisms responsible for the production of exotic species, mainly the projectile fragmentation and transfer reactions, are discussed, and the first experimental results presented. Results can be summarized as follows: existence of 4 new isotopes 22 C, 23 N, 29 Ne, 30 Ne; indication of bound character of 71 Ni, 72 Ni; clear evidence for bound character of 23 Si, 27 S, 31 Ar, 35 Ca; indications of bound character of 43 V, 46 Mn, 47 Mn, 48 Fe, 50 Co, 52 Co, 52 Ni, 55 Cu, 56 Cu

  9. Post-scission fission theory: Neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1997-01-01

    A survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N (E) and the average prompt neutron multiplicity bar ν p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the recent models. In particular, the dependencies of N (E) and bar ν p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N (E, E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limitations to current (and future) approaches

  10. Measurement of fission anisotropy for Ta

    Indian Academy of Sciences (India)

    F on many actinide targets with large deformations exhibit dramatic increase with decreasing energy [5]. In order to understand the data, an admixture of non compound reaction processes, like the fast fission, the quasifission with orientation dependence and the preequilibrium fission, is introduced as a source of fission like ...

  11. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    International Nuclear Information System (INIS)

    Nathan, A.M.; Sandorfi, A.M.

    1992-01-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of σ(700)-meson exchange in γγ→ππ processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the γΝ-Δ transition; pion photoproduction and the γΝ-Δ amplitudes; effective- lagrangians, Watson's theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p(rvec γ, π o ) reaction; multipole analyses and photo-decay couplings at intermediate energies; compton scattering off the proton; connections between compton scattering and pion photoproduction in the delta region; single-pion electroproduction and the transverse one-half and scalar helicity transition form factors; relativistic effects, QCD mixing angles, and Ν → Νγ and Δ → γΝ transition form factors; electroproduction studies of the Ν → Δ transition at bates and CEBAF

  12. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Nathan, A.M.; Sandorfi, A.M. [eds.

    1992-10-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of {sigma}(700)-meson exchange in {gamma}{gamma}{yields}{pi}{pi} processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the {gamma}{Nu}-{Delta} transition; pion photoproduction and the {gamma}{Nu}-{Delta} amplitudes; effective- lagrangians, Watson`s theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p({rvec {gamma}}, {pi}{sup o}) reaction; multipole analyses and photo-decay couplings at intermediate energies; compton scattering off the proton; connections between compton scattering and pion photoproduction in the delta region; single-pion electroproduction and the transverse one-half and scalar helicity transition form factors; relativistic effects, QCD mixing angles, and {Nu} {yields} {Nu}{gamma} and {Delta} {yields} {gamma}{Nu} transition form factors; electroproduction studies of the {Nu} {yields} {Delta} transition at bates and CEBAF.

  13. Evolution of collectivity in the 78Ni region: Coulomb excitation of 74Ni at intermediate energies.

    Directory of Open Access Journals (Sweden)

    Marchi T.

    2014-03-01

    Full Text Available The study of the collective properties of nuclear excitations far from stability provides information about the shell structure at extreme conditions. Spectroscopic observables such as the energy or the transition probabilities of the lowest states, in nuclei with large neutron excess, allow to probe the density and isospin dependence of the effective interaction. Indeed, it was recently shown that tensor and three-body forces play an important role in breaking and creating magic numbers. Emblematic is the case of the evolution of the Ni isotopic chain where several features showed up moving from the most neutron rich stable isotope (64Ni towards the 78Ni nucleus where the large neutron excess coincides with a double shell closure. In this framework, we have recently performed an experiment with the goal to extract the B(E2; 0+ → 2+ value for the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment: preliminary results are discussed.

  14. Intermediate milling energy optimization to enhance the characteristics of barium hexaferrite magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hodaei, A.; Ataie, A., E-mail: aataie@ut.ac.ir; Mostafavi, E.

    2015-08-15

    Highlights: • Nano-sized BaFe{sub 12}O{sub 19} was successfully synthesized via a solid-state reaction. • Intermediate milling energy was optimized to improve BaFe{sub 12}O{sub 19} properties. • Minimum total energy of 93.7 kJ/g was necessary for formation of BaFe{sub 12}O{sub 19}. • Deviation from the optimum milling energy deteriorates the magnetic properties. - Abstract: Nano-sized barium hexaferrite particles were synthesized by mechanical activation of BaCO{sub 3} and Fe{sub 2}O{sub 3} powders mixture as starting materials. The effects of mechanical milling energy on the phase composition, morphology, thermal behavior and magnetic properties of the samples were systematically investigated by employing X-ray diffractometer, field emission scanning electron microscopy, differential thermal/thermo gravimetry analysis and vibrating sample magnetometer, respectively. The milling energy was calculated at five different levels using collision model. It was found that there is an optimum milling energy value for obtaining barium hexaferrite phase. The results revealed that applying a minimum total milling energy of 93.7 kJ/g was necessary for formation of almost single barium hexaferrite at a relatively low calcination temperature of 800 °C. FESEM micrograph of the above sample exhibited nano-size particles with a mean particle size of 80 nm. Further increase in milling energy leads to dramatic decrease in phase purity as well as magnetic characteristics of the samples. By increasing the milling energy from 93.7 to 671.9 kJ/g, saturation magnetization (M{sub s}) decreased from 22.5 to 0.39 emu/g, and also coercivity (H{sub c}) decreased from 4.28 to 1.46 kOe.

  15. Ternary fission and cluster radioactivities

    CERN Document Server

    Poenaru, D N; Greiner, W; Gherghescu, R A; Hamilton, J H; Ramayya, A V

    2002-01-01

    Ternary fission yield for different kinds of light particle accompanied fission processes is compared to the Q-values for the corresponding cold phenomena, showing a striking correlation. The experimental evidence for the existence of a quasimolecular state in sup 1 sup 0 Be accompanied fission of sup 2 sup 5 sup 2 Cf may be explained using a three-center phenomenological model which generates a third minimum in the deformation energy at a separation distance very close to the touching point. This model is a natural extension of the unified approach to three groups of binary decay modes (cold fission, cluster radioactivities and alpha decay), illustrated by sup 2 sup 3 sup 4 U decay modes, and the alpha valley on the potential energy surfaces of sup 1 sup 0 sup 6 Te. New measurements of cluster decay modes, confirming earlier predictions within analytical superasymmetric fission model, are included in a comprehensive half-life systematics. (authors)

  16. The discovery of fission

    International Nuclear Information System (INIS)

    McKay, H.A.C.

    1978-01-01

    In this article by the retired head of the Separation Processes Group of the Chemistry Division, Atomic Energy Research Establishment, Harwell, U.K., the author recalls what he terms 'an exciting drama, the unravelling of the nature of the atomic nucleus' in the years before the Second World War, including the discovery of fission. 12 references. (author)

  17. Prompt- and delayed-fission probabilities in actinides within a doorway state model

    International Nuclear Information System (INIS)

    Bellia, G.; Del Zoppo, A.; Migneco, E.; Russo, G.

    1984-01-01

    The formalism of the doorway state model for fission is extended to excitation energy as low as the pairing gap region in the intermediate well of the potential barrier. Expressions for the wave function amplitudes which describe the various possible admixtures of the vibrational modes into the compound-state sets are generalized and can be used to calculate prompt- and delayed-fission probabilities in the energy range between the isomer level and the top of the barrier. The occurrence of different coupling situations for the 238 U 1 - 0 channel is discussed

  18. Prompt- and delayed-fission probabilities in actinides within a doorway state model

    Energy Technology Data Exchange (ETDEWEB)

    Bellia, G.; Del Zoppo, A.; Migneco, E.; Russo, G. (Istituto Nazionale di Fisica Nucleare, Catania (Italy); Catania Univ. (Italy). Ist. di Fisica)

    1984-01-21

    The formalism of the doorway state model for fission is extended to excitation energy as low as the pairing gap region in the intermediate well of the potential barrier. Expressions for the wave function amplitudes which describe the various possible admixtures of the vibrational modes into the compound-state sets are generalized and can be used to calculate prompt- and delayed-fission probabilities in the energy range between the isomer level and the top of the barrier. The occurrence of different coupling situations for the /sup 238/U 1/sup -/0 channel is discussed.

  19. The modal structure of fragment mass and energy yields from the 10.3-30.0 MeV proton induced fission of {sup 232}Th and {sup 235}U

    Energy Technology Data Exchange (ETDEWEB)

    Mulgin, S.I. [Institute of Nuclear Physics, National Nuclear Center, 050032 Almaty (Kazakhstan); Zhdanov, S.V. [Institute of Nuclear Physics, National Nuclear Center, 050032 Almaty (Kazakhstan)], E-mail: zhdanov@inp.kz; Kondratiev, N.A. [Flerov' s Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Kovalchuk, K.V.; Rusanov, A.Ya. [Institute of Nuclear Physics, National Nuclear Center, 050032 Almaty (Kazakhstan)

    2009-06-01

    Mass and energy distributions of fragments from fission of target nuclei {sup 232}Th and {sup 235}U induced by the 10.3-30.0 MeV protons have been measured with surface-barrier silicon detectors. A new method for decomposition of experimental distributions into fragment mass and energy yields of four independent fission modes has been proposed. Main characteristics of fission modes such as distinct mode mass yields, mean masses and kinetic energies as well as variances in fragment masses and energies have been studied in relation with energy of protons. Revealed regularities in these quantities for given energy range of incident protons support the assumption that the modes S1 and S2 are initially formed in a unified asymmetric fission valley.

  20. Emission of high-energy, light particles from intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Ball, J.B.; Auble, R.L.

    1982-01-01

    One of the early surprises in examining reaction products from heavy ion reactions at 10 MeV/nucleon and above was the large yield of light particles emitted and the high energies to which the spectra of these particles extended. The interpretation of the origin of the high energy light ions has evolved from a picture of projectile excitation and subsequent evaporation to one of pre-equilibrium (or nonequilibrium) emission. The time scale for particle emission has thus moved from one that occurs following the initial collision to one that occurs at the very early stages of the collision. Research at ORNL on this phenomenon is reviewed

  1. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 5: Conclusions and recomendations

    Science.gov (United States)

    Williams, J. R.

    1974-01-01

    Air pollution resulting from the use of fossil fuels is discussed. Phenomena relating to the emission of CO2 such as the greenhouse effect and multiplier effect are explored. Particulate release is also discussed. The following recommendations are made for the elimination of fossil fuel combustion products in the United States: development of nuclear breeder reactors, use of solar energy systems, exploration of energy alternatives such as geothermal and fusion, and the substitution of coal for gas and oil use.

  2. Detecting special nuclear materials in suspect containers using high-energy gamma rays emitted by fission products

    Science.gov (United States)

    Norman, Eric B [Oakland, CA; Prussin, Stanley G [Kensington, CA

    2009-01-27

    A method and a system for detecting the presence of special nuclear materials in a suspect container. The system and its method include irradiating the suspect container with a beam of neutrons, so as to induce a thermal fission in a portion of the special nuclear materials, detecting the gamma rays that are emitted from the fission products formed by the thermal fission, to produce a detector signal, comparing the detector signal with a threshold value to form a comparison, and detecting the presence of the special nuclear materials using the comparison.

  3. An analytic solution for energy loss and time-of-flight calculations for intermediate-energy light ions

    CERN Document Server

    Snellings, R; Prendergast, E P; Brink, A V D; Haas, A P D; Habets, J J L; Kamermans, R; Koopmans, M; Kuijer, P G; Laat, C T A; Ostendorf, R W; Peghaire, A; Rossewij, M

    1999-01-01

    Particle identification in intermediate heavy-ion collisions, using a modern 4 pi detector which contains several active layers, relies on a parametrisation or numerical integration of the energy loss in thick layers of detector material for different ions. Here an analytical solution applicable over an energy range of a few MeV up to a 100A MeV and for ions up to at least Z=8 is presented. Also, the consequences for time-of-flight measurements (TOF) in detectors behind several thick layers of detector material are discussed. The solution is applied to the data of the Huygens detector, which uses a TPC (dE/dx) and plastic scintillators for particle identification (E and TOF or dE/dx and TOF).

  4. Measurement of the energy spectrum of {sup 252}Cf fission fragments using nuclear track detectors and digital image processing

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Castano, V. M. [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Boulevard Juriquilla 3001, Santiago de Queretaro, 76230 Queretaro (Mexico); Gaso, I. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Mena, M.; Segovia, N. [UNAM, Instituto de Geofisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    The energy spectrum of {sup 252}Cf fission fragments was measured using nuclear track detectors and digital image analysis system. The detection material was fused silica glass. The detectors were chemically etched in an 8% HF solution. After experimenting with various etching time, it was found that the best resolution of the track diameter distribution was obtained after 30 minutes of etching. Both Gaussian and Lorentzian curves were fit to the track diameter distribution histograms and used to determine the basic parameters of the distribution of the light (N{sub L}) and heavy (N{sub H}) formed peaks and the minimum of the central valley (N{sub V}). Advantages of the method presented here include the fully-automated analysis process, the low cost of the nuclear track detectors and the simplicity of the nuclear track method. The distribution resolution obtained by this method is comparable with the resolution obtained by electronic analysis devices. The descriptive variables calculated were very close to those obtained by other methods based on the use of semiconductor detectors. (Author)

  5. Determination of the fission barrier height in fission of heavy radioactive beams induced by the (d,p)-transfer

    CERN Multimedia

    A theoretical framework is described, allowing to determine the fission barrier height using the observed cross sections of fission induced by the (d,p)-transfer with accuracy, which is not achievable in another type of low-energy fission of neutron-deficient nuclei, the $\\beta$-delayed fission. The primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission of...

  6. Role of energy cost in the yield of cold ternary fission of 252 Cf

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 80; Issue 1. Role of energy cost in the yield of cold ... P V Kunhikrishnan1 K P Santhosh2. P.G. Department of Physics, Sree Narayana College, Kannur 670 007, India; School of Pure & Applied Physics, Kannur University, Payyanur Campus, Payyanur 670 327, India ...

  7. Historical evolution of nuclear energy systems development and related activities in JAERI. Fission, fusion, accelerator utilization

    Energy Technology Data Exchange (ETDEWEB)

    Tone, Tatsuzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    Overview of the historical evolution of nuclear energy systems development and related activities in JAERI is given in the report. This report reviews the research and development for light water reactor, fast breeder reactor, high temperature gas reactor, fusion reactor and utilization of accelerator-based neutron source. (author)

  8. Neutron-proton bremsstrahlung from intermediate energy heavy-ion reactions as a probe of the nuclear symmetry energy?

    International Nuclear Information System (INIS)

    Yong, G.-C.; Li Baoan; Chen Liewen

    2008-01-01

    Hard photons from neutron-proton bremsstrahlung in intermediate energy heavy-ion reactions are examined as a potential probe of the nuclear symmetry energy within a transport model. Effects of the symmetry energy on the yields and spectra of hard photons are found to be generally smaller than those due to the currently existing uncertainties of both the in-medium nucleon-nucleon cross sections and the photon production probability in the elementary process pn→pnγ. Very interestingly, nevertheless, the ratio of hard photon spectra R 1/2 (γ) from two reactions using isotopes of the same element is not only approximately independent of these uncertainties but also quite sensitive to the symmetry energy. For the head-on reactions of 132 Sn + 124 Sn and 112 Sn + 112 Sn at E beam /A=50 MeV, for example, the R 1/2 (γ) displays a rise up to 15% when the symmetry energy is reduced by about 20% at ρ=1.3ρ 0 which is the maximum density reached in these reactions

  9. Ternary fission

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary ...

  10. The role of non-elastic nuclear processes for intermediate-energy protons in silicon targets

    International Nuclear Information System (INIS)

    Hormaza, Joel Mesa; Garcia, Cesar E.; Arruda Neto, Joao D.T.; Rodrigues, Tulio E.; Paschuck, Sergei A.; Evseev, Ivan

    2013-01-01

    The transportation of energetic ions in bulk matter is of direct interest in several areas including shielding against ions originating from either space radiations or terrestrial accelerators, cosmic ray propagation studies in galactic medium, or radiobiological effects resulting from the work place or clinical exposures. For carcinogenesis, terrestrial radiation therapy, and radiobiological research, knowledge of beam composition and interactions is necessary to properly evaluate the effects on human and animal tissues. For the proper assessment of radiation exposures both reliable transport codes and accurate input parameters are needed. In the last years efforts have been increasing in order to develop more effective models to describe and predict the damages induced by radiation in electronic devices. In this sense, the interaction of protons with those devices, particularly which operate in space, is a topic of paramount importance, mainly because although the majority of them are made with silicon, experimental data on p+Si nuclear processes is very sparse. In this work we have used a new quite sophisticated Monte Carlo multicollisional intranuclear cascade (MCMC) code for pre-equilibrium emission, plus de-excitation of residual nucleus by two ways: evaporation of particles (mainly nucleons, but also composites) and possibly fragmentation/fission in the case of heavy residues, in order to study some observable of nuclear interaction of protons between 100-200 MeV in a 28 Si target. The code has been developed with very recent improvements that take into account Pauli blocking effects in a novel and more precise way, as well as a more rigorous energy balance, an energy stopping time criterion for pre-equilibrium emission and the inclusion of deuteron, triton and 3He emissions in the evaporation step, which eventually concurs with fragmentation/break-up stage. The fragment mass distributions, as well as the multiplicities and the spectra of secondary particles

  11. Excitation of vibrational quanta in furfural by intermediate-energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Costa, R. F. da [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 09210-580 São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo, São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); and others

    2015-12-14

    We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.

  12. Probing core polarization around 78Ni: intermediate energy Coulomb excitation of 74Ni

    Directory of Open Access Journals (Sweden)

    Marchi T.

    2013-12-01

    We have recently measured the B(E2; 0+ → 2+ of the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment performed at the National Superconducting Cyclotron Laboratory of the Michigan State University. The 74Ni secondary beam has been produced by fragmentation of 86Kr at 140 AMeV on a thick Be target. Selected radioactive fragments impinged on a secondary 197Au target where the measurement of the emitted γ-rays allows to extract the Coulomb excitation cross section and related structure information. Preliminary B(E2 values do not point towards an enhancement of the transition matrix element and the comparison to what was already measured by Aoi and co-workers in [1] opens new scenarios in the interpretation of the shell evolution of the Z=28 isotopes.

  13. Study of the neutron rich sulfure isotope 43S through intermediate energy Coulomb excitation

    Science.gov (United States)

    Calinescu, S.; Cáceres, L.; Grévy, S.; Sohler, D.; Stanoiu, M.; Negoita, F.; Borcea, C.; Borcea, R.; Bowry, M.; Catford, W.; Dombradi, Z.; Franchoo, S.; Gillibert, R.; Thomas, J. C.; Kuti, I.; Lukyanov, S.; Lepailleur, A.; Mrazek, J.; Niikura, M.; Podolyak, Z.; Petrone, C.; Penionzhkevich, Y.; Roger, T.; Rotaru, F.; Sorlin, O.; Stefan, I.; Vajta, Z.; Wilson, E.

    2013-02-01

    The reduced transition probability B(E2: 3/2- 7/2-2) has been measured in 43S using Coulomb excitation at intermediate energy. The nucleus of interest was produced by fragmentation of a 48Ca beam at GANIL. The reaction products were separated in the LISE spectrometer. After Coulomb-excitation of 43S in a 208Pb target, the γ rays emitted inflight were detected by 64 BaF2 detectors of the Chǎteau de Cristal array. The preliminary value deduced for the reduced transition probability B(E2: 3/2-7/2-2) is in agreement with the predictions of the shell model calculations and supports a prolate-spherical shape coexistence in the 43S nucleus.

  14. Inclusive photoproduction and electroproduction of intermediate vector bosons (W+-,Z0) at very high energies

    International Nuclear Information System (INIS)

    Hayashi, Masaki; Katsuura, Kazuo

    1979-01-01

    Adopting the quark-parton model based on QCD we estimate the cross-sections dσ/dt and σsup(tot) for the inclusive photoproduction of the intermediate vector bosons W + and Z 0 (γ + p → W + , Z 0 + anything) and σsup(tot) for the inclusive electroproduction (e - + p → W + , Z 0 + anything) at very high energies. The typical values of the estimated total cross-sections at √s >= 200 GeV are σsub(rp→W + ) -- 10 -36 cm 2 , σsub(ep→W + ) -- 10 -37 cm 2 , σsub(rp→Z 0 ) -- 10 -37 cm 2 and σsub(ep→Z 0 ) -- 10 -38 cm 2 with the Weinberg angle sin 2 theta sub( w) = 0.22. (author)

  15. Study of halo nuclei breakup on light targets at intermediate and high energies

    CERN Document Server

    Parfenova, Ioulia

    2002-01-01

    The study of exotic nuclei is one of the most important topics in modern nuclear physics. It allows general understanding of the structure and nature of light nuclear systems in the vicinity of the driplines. Most of the leading facilities in the world, CERN, GANIL, GSI in Europe, RIKEN in Japan, and NSCL(MSU) in USA, are involved in these investigations. Recently, new experimental data on the properties of light halo nuclei such as extremely large interaction cross sections, huge electromagnetic dissociation cross sections, narrow momentum distribution of fragments from breakup reactions, unusual modes of the beta-decay of these nuclei on the borders of the stability, were obtained. This Thesis is based on a series of articles devoted to theoretical investigations of nuclear breakup reactions with light halo nuclei at intermediate energies impinging on light target nuclei. Special attention is paid to the question of sensitivity of the calculated breakup cross sections and longitudinal momentum distributions...

  16. Assessment of high temperature nuclear energy storage systems for the production of intermediate and peak-load electric power

    International Nuclear Information System (INIS)

    Fox, E.C.; Fuller, L.C.; Silverman, M.D.

    1977-01-01

    Increased cost of energy, depletion of domestic supplies of oil and natural gas, and dependence on foreign suppliers, have led to an investigation of energy storage as a means to displace the use of oil and gas presently being used to generate intermediate and peak-load electricity. Dedicated nuclear thermal energy storage is investigated as a possible alternative. An evaluation of thermal storage systems is made for several reactor concepts and economic comparisons are presented with conventional storage and peak power producing systems. It is concluded that dedicated nuclear storage has a small but possible useful role in providing intermediate and peak-load electric power

  17. Mechanisms of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.

    1991-01-01

    The time evolution in fission is the starting point for discussing not only the main mechanism of fission neutron emission, the evaporation from fully accelerated fragments, but also possible secondary ones connected with dynamical features of nuclear fission. ''Asymptotic'' conditions as relevant for describing the particle release from highly excited, rapidly moving fragments are defined. Corresponding statistical model approaches to fission neutron emission, based on the adequate consideration of the intricate fragment occurrence probability, reproduce most of the experimental data. The remarkable influence of fission modes on neutron observables is analyzed in the framework of a macroscopic-microscopic scission point model consistent with energy conservation. Finally, chances and deficiencies for solving the mechanism puzzle are summarized. (author). 87 refs, 21 figs

  18. Nuclear fission, the energy of the future; La fision nuclear como energia del futuro

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Val, J. M.; Fernandez, J. A.; Leon, P. T.

    2002-07-01

    The design of new-generation nuclear power stations incorporates approaches and control systems which significantly reduce risk and waste generation, while enhancing an installation's performance. This article reviews current programs involving the world's advanced reactors,and other future systems such as rapid reproduction reactors, or those operating in sub-critical conditions as energy amplifier. (Author) 12 refs.

  19. Excited state conformational dynamics in carotenoids: dark intermediates and excitation energy transfer.

    Science.gov (United States)

    Beck, Warren F; Bishop, Michael M; Roscioli, Jerome D; Ghosh, Soumen; Frank, Harry A

    2015-04-15

    A consideration of the excited state potential energy surfaces of carotenoids develops a new hypothesis for the nature of the conformational motions that follow optical preparation of the S2 (1(1)Bu(+)) state. After an initial displacement from the Franck-Condon geometry along bond length alternation coordinates, it is suggested that carotenoids pass over a transition-state barrier leading to twisted conformations. This hypothesis leads to assignments for several dark intermediate states encountered in femtosecond spectroscopic studies. The Sx state is assigned to the structure reached upon the onset of torsional motions near the transition state barrier that divides planar and twisted structures on the S2 state potential energy surface. The X state, detected recently in two-dimensional electronic spectra, corresponds to a twisted structure well past the barrier and approaching the S2 state torsional minimum. Lastly, the S(∗) state is assigned to a low lying S1 state structure with intramolecular charge transfer character (ICT) and a pyramidal conformation. It follows that the bent and twisted structures of carotenoids that are found in photosynthetic light-harvesting proteins yield excited-state structures that favor the development of an ICT character and optimized energy transfer yields to (bacterio)chlorophyll acceptors. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. (d,p)-transfer induced fission of heavy radioactive beams

    CERN Document Server

    Veselsky, Martin

    2012-01-01

    (d,p)-transfer induced fission is proposed as a tool to study low energy fission of exotic heavy nuclei. Primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission offers a possibility for systematic study the low energy fission of heavy exotic nuclei at the ISOLDE.

  1. Heavy-ion induced fission reactions

    International Nuclear Information System (INIS)

    Britt, H.C.; Fowler, M.M.; Fraenkel, Z.; Gavron, A.; Plicht, J.; Wilhelmy, J.B.; Plasil, F.; Awes, T.; Young, G.

    1983-01-01

    Heavy-ion induced fission reactions are investigated. The problem of obtaining a representative set of fission-cross section data, so that it would be possible to test both the mass and angular momentum dependence of fission barriers in the mass region 150 9 Be through 64 Ni. The experimental data clearly show the qualitative effects of angular momentum, excitation energy and fissility on the fission cross section. They provide an ideal testing ground for theoretical models of fission in this mass region

  2. Fission modelling with FIFRELIN

    Energy Technology Data Exchange (ETDEWEB)

    Litaize, Olivier; Serot, Olivier; Berge, Leonie [CEA, DEN, DER, SPRC, Saint Paul Lez Durance (France)

    2015-12-15

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e{sup -}). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for

  3. Nuclear Power from Fission Reactors. An Introduction.

    Science.gov (United States)

    Department of Energy, Washington, DC. Technical Information Center.

    The purpose of this booklet is to provide a basic understanding of nuclear fission energy and different fission reaction concepts. Topics discussed are: energy use and production, current uses of fuels, oil and gas consumption, alternative energy sources, fossil fuel plants, nuclear plants, boiling water and pressurized water reactors, the light…

  4. Constructing effective one-body dynamics with numerical energy flux for intermediate-mass-ratio inspirals

    International Nuclear Information System (INIS)

    Han Wenbiao; Cao Zhoujian

    2011-01-01

    A new scheme for computing dynamical evolutions and gravitational radiations for intermediate-mass-ratio inspirals (IMRIs) based on an effective one-body (EOB) dynamics plus Teukolsky perturbation theory is built in this paper. In the EOB framework, the dynamic essentially affects the resulted gravitational waveform for a binary compact star system. This dynamic includes two parts. One is the conservative part, which comes from effective one-body reduction. The other part is the gravitational backreaction, which contributes to the shrinking process of the inspiral of a binary compact star system. Previous works used an analytical waveform to construct this backreaction term. Since the analytical form is based on post-Newtonian expansion, the consistency of this term is always checked by numerical energy flux. Here, we directly use numerical energy flux by solving the Teukolsky equation via the frequency-domain method to construct this backreaction term. The conservative correction to the leading order terms in mass-ratio is included in the deformed-Kerr metric and the EOB Hamiltonian. We try to use this method to simulate not only quasicircular adiabatic inspiral, but also the nonadiabatic plunge phase. For several different spinning black holes, we demonstrate and compare the resulted dynamical evolutions and gravitational waveforms.

  5. Direct processes in ion-atom collisions at intermediate and high energies

    International Nuclear Information System (INIS)

    Rodriguez Chariarse, V.D.

    1990-01-01

    This thesis deals with direct processes induced by Zp charge ion impact on one or two electron atoms and ions at intermediate energies. At a first step, a one-dimensional collision model is used in order to prove the different theoretical methods available to study collisions at such energy range, such as: perturbative and related variational principles, and distorted wave methods. The best description of both, symmetric and asymmetric collision type, is achieved by the distorted wave methods, particularly the ones using the exact impulsive wave function. As a next step, the appropriate formulations of the wave functions employed in the one-dimensional model to describe the real 3-dimensional Coulomb interaction case are examined by using the Eikonal and impulse hypothesis. In this way, the VPS and Eikonal wave functions are reviewed, and furtherly, the Eikonal form of the extended impulse wave function is derived. The Eikonal impulse approximation (EIA) is introduced. This is a distorted wave method using the Eikonal and extended impulse wave functions. The choice of the EIA prior version, i.e., the one using extended impulse wave function in the final channel for excitation is widely discussed and justified. (Author) [es

  6. Long-term residual radioactivity in an intermediate-energy proton linac

    Science.gov (United States)

    Blaha, J.; La Torre, F. P.; Silari, M.; Vollaire, J.

    2014-07-01

    A new 160 MeV H- linear accelerator (LINAC4) is being installed at CERN to replace the present 50 MeV LINAC2 as proton injector of the PS Booster (PSB). During operation, the accelerator components will be activated by the beam itself and by the secondary radiation field. Detailed Monte Carlo simulations, for various beam energies and several decay times, were performed to predict the residual radioactivity in the main accelerator components and to estimate the residual dose rate inside the tunnel. The results of this study will facilitate future dismantling, handling and storage of the activated parts and consequently minimize the radiation dose to involved workers. The component activation was also compared with the exemption limits given in the current Swiss legislation and to the CERN design values, in order to make predictions for the future storage and disposal of radioactive waste. The airborne radioactivity induced by particles escaping the beam dump and the activation of the beam dump cooling water circuit were also quantified. The aim of this paper is to provide data of sufficiently general interest to be used for similar studies at other intermediate-energy proton accelerator facilities.

  7. Long-term residual radioactivity in an intermediate-energy proton linac

    International Nuclear Information System (INIS)

    Blaha, J.; La Torre, F.P.; Silari, M.; Vollaire, J.

    2014-01-01

    A new 160 MeV H − linear accelerator (LINAC4) is being installed at CERN to replace the present 50 MeV LINAC2 as proton injector of the PS Booster (PSB). During operation, the accelerator components will be activated by the beam itself and by the secondary radiation field. Detailed Monte Carlo simulations, for various beam energies and several decay times, were performed to predict the residual radioactivity in the main accelerator components and to estimate the residual dose rate inside the tunnel. The results of this study will facilitate future dismantling, handling and storage of the activated parts and consequently minimize the radiation dose to involved workers. The component activation was also compared with the exemption limits given in the current Swiss legislation and to the CERN design values, in order to make predictions for the future storage and disposal of radioactive waste. The airborne radioactivity induced by particles escaping the beam dump and the activation of the beam dump cooling water circuit were also quantified. The aim of this paper is to provide data of sufficiently general interest to be used for similar studies at other intermediate-energy proton accelerator facilities

  8. A comparison of the radiological impact of energy production by fission and fusion reactions

    International Nuclear Information System (INIS)

    Rancillac, F.; Despres, A.

    1990-04-01

    The impacts of respectively a light water reactor and a planned fusion reactor, for which tritium-deuterium fusion reactions will act as energy source have been compared. The comparison is made on the basis of a generated capacity of 1 GWe.year, using the following criteria: fuel inventories, radioactive releases, collective effective dose equivalent commitments to the public and the volume of wastes. The accidental risk is not introduced. Fusion reactor parameters are still subject to uncertainties, which prevent accurate quantification of radionuclide releases (tritium apart) from the nuclear plant. Only orders of magnitude extrapolated from values for the NET tokamak are given. Despite these uncertainties, it would seem more interesting, from the dosimetric point of view, to use fusion reactors to produce electricity, although problems of radioactive releases, handling and long-term storage of radioactive waste would remain. Fusion reactors also generate generate high-level wastes with long-term exposure rates that are lower than those of light water reactors [fr

  9. HYPERFUSE: a novel inertial confinement system utilizing hypervelocity projectiles for fusion energy production and fission waste transmutation

    International Nuclear Information System (INIS)

    Makowitz, H.; Powell, J.R.; Wiswall, R.

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from an LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., 137 Cs or 90 Sr. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n, 2n), (n, α), etc.) that convert the long lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product

  10. The evaluation of the 237Np fission cross section in the 20 KeV - 20 MeV energy range

    International Nuclear Information System (INIS)

    Dushin, V.N.; Kalinin, V.A.; Shpakov, V.I.

    1997-01-01

    The results of the development of nuclear data evaluation based on the generalized least squares method is presented. The method to interpolate experimental data measured at arbitrary energy points, and their transfer to a fixed energy grid is described. The results of the 237 Np fission cross section measurements performed until 1988 were critically analyzed. A 781 x 781 covariant matrix was derived from the correlation analysis of the experimental results. The results of the evaluation, and the associated correlation matrix was obtained using the generalized least square method. (author). 34 refs, 4 figs, 2 tabs

  11. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei.

  12. Numerical comparison between deep water and intermediate water depth expressions applied to a wave energy converter

    Directory of Open Access Journals (Sweden)

    Pedro Beirão

    2015-09-01

    Full Text Available The energy that can be captured from the sea waves and converted into electricity should be seen as a contribution to decrease the excessive dependency and growing demand of fossil fuels. Devices suitable to harness this kind of renewable energy source and convert it into electricity—wave energy converters (WECs—are not yet commercially competitive. There are several types of WECs, with different designs and working principles. One possible classification is their distance to the shoreline and thus their depth. Near-shore devices are one of them since they are typically deployed at intermediate water depth (IWD. The selection of the WEC deployment site should be a balance between several parameters; water depth is one of them. Another way of classifying WECs is grouping them by their geometry, size and orientation. Considering a near-shore WEC belonging to the floating point category, this paper is focused on the numerical study about the differences arising in the power captured from the sea waves when the typical deep water (DW assumption is compared with the more realistic IWD consideration. Actually, the production of electricity will depend, among other issues, on the depth of the deployment site. The development of a dynamic model including specific equations for the usual DW assumption as well as for IWD is also described. Derived equations were used to build a time domain simulator (TDS. Numerical results were obtained by means of simulations performed using the TDS. The objective is to simulate the dynamic behavior of the WEC due to the action of sea waves and to characterize the wave power variations according with the depth of the deployment site.

  13. Inner-shell excitation in heavy ion collisions up to intermediate incident energies

    International Nuclear Information System (INIS)

    Reus, T. de.

    1987-04-01

    Electronic excitations in collisions of very heavy ions with a total nuclear charge Z greater than 1/α ≅ 137 at bombarding energies reaching from 3.6 MeV/n up to 100 MeV/n are the subject of this thesis. The dynamical behaviour of the electron-positron-field is described within a semiclassical model, which is reviewed and extended to include electronic interactions via a mean field. A detailed comparison with experimental data of K-vacancy formation, δ-electron and positron emission shows an improved agreement compared with former calculations. Structures in spectra of positrons emitted in sub- and supercritical collision are discussed in two respects: Firstly as a signal of the vacuum decay in supercritical electromagnetic fields which evolve in the vicinity of long living giant nuclear molecules. Secondly as an atomic effect, which might be related to an instaneous formation of molecular 1sσ- and 2p 1/2 σ- levels. However, beyond this speculation the emission spectra of electrons and positrons in deep inelastic reactions have proven to be a powerful tool for measuring nuclear reaction or delay times in the order of 10 -21 s. This property was transfered to the domain of intermediate energy collisions. In first order perturbation theory we derived a scaling law, exhibiting how nuclear stopping times could be extracted from the emission spectra of high energetic δ-electrons. Quantitative calculations within a coupled channel code have been carried out for the system Pb+Pb, yielding cross sections of up to 20 nb for the emission of electrons with a kinetic energy of 50 MeV in 60 MeV/n-collisions. (orig./HSI)

  14. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies: Final report

    International Nuclear Information System (INIS)

    Burleson, G.R.

    1987-01-01

    We are applying for a three-year grant from the US Department of Energy to New Mexico State University to continue its support of our work on experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies, which has been carried out in collaboration with groups from various laboratories and universities. The nucleon-nucleon work is aimed at making measurements that will contribute to a determination of the isospin-zero amplitudes, as well as continuing our investigations of evidence for dibaryon resonances. It is based at the LAMPF accelerator in Los Alamos, New Mexico. Current and planned experiments include measurements of total cross-section differences in pure spin states and of spin parameters in neutron-proton scattering. The pion-nucleus work is aimed at improving our understanding both of the nature of the pion-nucleus interaction and of nuclear structure. It consists of two programs, one based at LAMPF and one based principally at the SIN laboratory in Switzerland. The LAMPF-based work involves studies of large-angle scattering, double-charge-exchange scattering, including measurements at a new energy range above 300 MeV, and a new program of experiments with polarized nuclear targets. The SIN-based work involves studies of quasielastic scattering and absorption, including experiments with a new large-acceptance detector system planned for construction there. We are requesting support to continue the LAMPF-based work at its current level and to expand the SIN-based work to allow for increased involvement in experiments with the new detector system. 57 refs

  15. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    1990-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei

  16. Theoretical Description of the Fission Process

    Energy Technology Data Exchange (ETDEWEB)

    Witold Nazarewicz

    2003-07-01

    The main goals of the project can be summarized as follows: Development of effective energy functionals that are appropriate for the description of heavy nuclei. Our goal is to improve the existing energy density (Skyrme) functionals to develop a force that will be used in calculations of fission dynamics. Systematic self-consistent calculations of binding energies and fission barriers of actinide and trans-actinide nuclei using modern density functionals. This will be followed by calculations of spontaneous fission lifetimes and mass and charge divisions using dynamic adiabatic approaches based on the WKB approximation. Investigate novel microscopic (non-adiabatic) methods to study the fission process.

  17. Theoretical Description of the Fission Process

    International Nuclear Information System (INIS)

    Witold Nazarewicz

    2003-01-01

    The main goals of the project can be summarized as follows: Development of effective energy functionals that are appropriate for the description of heavy nuclei. Our goal is to improve the existing energy density (Skyrme) functionals to develop a force that will be used in calculations of fission dynamics. Systematic self-consistent calculations of binding energies and fission barriers of actinide and trans-actinide nuclei using modern density functionals. This will be followed by calculations of spontaneous fission lifetimes and mass and charge divisions using dynamic adiabatic approaches based on the WKB approximation. Investigate novel microscopic (non-adiabatic) methods to study the fission process

  18. Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy

    Science.gov (United States)

    McIntyre, Peter; Assadi, Saeed; Badgley, Karie; Baker, William; Comeaux, Justin; Gerity, James; Kellams, Joshua; McInturff, Al; Pogue, Nathaniel; Phongikaroon, Supathorn; Sattarov, Akhdiyor; Simpson, Michael; Sooby, Elizabeth; Tsvetkov, Pavel

    2013-04-01

    A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

  19. Proceedings of the workshop on program options in intermediate-energy physics. Volume 1. Summary and panel reports

    Energy Technology Data Exchange (ETDEWEB)

    Allred, J.C.; Talley, B. (comps.)

    1980-05-01

    A Workshop on Program Options in Intermediate-Energy Physics sponsored by the US Department of Energy was held at Los Alamos Scientific Laboratory, August 20 to 31, 1979. The scope of the workshop included all laboratories in intermediate-energy physics, worldwide, and all of these sent representatives to the workshop. The workshop addressed itself to the critical questions on nuclear and particle physics and how they can best be investigated by intermediate-energy accelerators. Among the questions that the workshop members considered were: (1) what are the important physics topics which might be understood through research on these accelerators in the next 10 years. These topics include, but are not restricted to, fundamental interactions and symmetries in particle physics, and nuclear modes of motion, structure, and reaction mechanisms; (2) what experiments should be undertaken to carry out the program. What are the kinematical conditions, accuracies, resolutions, and other parameters required to obtain the desired knowledge; (3) which accelerators are best suited for each experiment. What work at other laboratories (low-, intermediate-, or high-energy) could be undertaken to complement and/or supplement the proposed LAMPF program; and (4) what new facility capabilities should be explored for the long-term future. The workshop was divided into small panels in order to promote effective interchange of ideas. After reports to other panels and plenary sessions, the panelists prepared reports stating the results of their deliberations. These reports comprise the principal part of Volume I.

  20. Proceedings of the workshop on program options in intermediate-energy physics. Volume 1. Summary and panel reports

    International Nuclear Information System (INIS)

    Allred, J.C.; Talley, B.

    1980-05-01

    A Workshop on Program Options in Intermediate-Energy Physics sponsored by the US Department of Energy was held at Los Alamos Scientific Laboratory, August 20 to 31, 1979. The scope of the workshop included all laboratories in intermediate-energy physics, worldwide, and all of these sent representatives to the workshop. The workshop addressed itself to the critical questions on nuclear and particle physics and how they can best be investigated by intermediate-energy accelerators. Among the questions that the workshop members considered were: (1) what are the important physics topics which might be understood through research on these accelerators in the next 10 years. These topics include, but are not restricted to, fundamental interactions and symmetries in particle physics, and nuclear modes of motion, structure, and reaction mechanisms; (2) what experiments should be undertaken to carry out the program. What are the kinematical conditions, accuracies, resolutions, and other parameters required to obtain the desired knowledge; (3) which accelerators are best suited for each experiment. What work at other laboratories (low-, intermediate-, or high-energy) could be undertaken to complement and/or supplement the proposed LAMPF program; and (4) what new facility capabilities should be explored for the long-term future. The workshop was divided into small panels in order to promote effective interchange of ideas. After reports to other panels and plenary sessions, the panelists prepared reports stating the results of their deliberations. These reports comprise the principal part of Volume I

  1. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    3Istituto Nazionale di Fisica Nucleare, Via G Sansone 1, 50019, Sesto Fiorentino (Firenze), Italy. 4Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research,. 141980 Dubna, Russia. 5Present address: Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany. 6Present address: Omsk State ...

  2. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    2015-07-26

    Jul 26, 2015 ... Dipartimento di Fisica, Università di Napoli “Federico II” and INFN, Complesso Universitario Monte Sant'Angelo, Via Cintia, Edificio 6, 80126, Napoli, Italy; Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany; Omsk State University, Mira prospekt 55-A, Omsk 644077, Russia; Laboratori ...

  3. Intermediate energies heavy ion collisions : study of the charged particles emission dynamics and emitters characterization

    International Nuclear Information System (INIS)

    Bauge, E.

    1994-07-01

    In heavy ion collisions at intermediate energies, reaction processes are ranging from slow processes where equilibrium is achieved between every emission, up to direct processes where nucleon nucleon scattering and phase space availability are the deciding factors. In order to investigate this transition, both the emission dynamics and the characteristics of the emitter have been studied, both theoretically and experimentally in the AMPHORA detector, for the systems 7, 17, 27 and 34 AMeV, 40 Ar+Al, 40 Ar+Cu and 40 Ar+Ag. First, the linear momentum transfer of the most central collisions has been evaluated for these systems, by measuring the velocity of heavy residues. Then, by measuring azimuthal angle correlations functions, and by comparing them with statistical model predictions, the average angular momentum of the emitter has been evaluated. To study the charged particles emission dynamics, experimental azimuthal angle and relative momentum correlation functions have been compared with simulations based on a classical trajectory model. Finally, predictions of an advanced BUU model have been studied for the system 34 AMeV 40 Ar+Al. (authors). 69 refs., 52 figs., 5 tabs

  4. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Nathan, A.M.; Sandorfi, A.M. (eds.)

    1992-01-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of [sigma](700)-meson exchange in [gamma][gamma][yields][pi][pi] processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the [gamma][Nu]-[Delta] transition; pion photoproduction and the [gamma][Nu]-[Delta] amplitudes; effective- lagrangians, Watson's theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p([rvec [gamma

  5. Modeling interactions of intermediate-energy neutrons in a plastic scintillator array with GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Kohley, Z., E-mail: zkohley@gmail.com [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Lunderberg, E.; DeYoung, P.A. [Department of Physics, Hope College, Holland, MI 49423 (United States); Roeder, B.T. [LPC-Caen, ENSICAEN, IN2P3/CNRS et Universite de Caen, 14050 Caen cedex (France); Baumann, T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Christian, G.; Mosby, S.; Smith, J.K.; Snyder, J.; Spyrou, A.; Thoennessen, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-08-01

    A Monte Carlo simulation of a large-area neutron time-of-flight detector, built on the GEANT4 framework, has been compared with an experimental measurement of the {sup 16}B{yields}{sup 15}B+n decay produced from a 55 MeV/u{sup 17}C beam. The ability of the Monte Carlo simulation to reproduce the intermediate-energy neutron interactions within the detector has been explored using both the stock GEANT4 physics processes and a custom neutron interaction model, MENATE{sub R}. The stock GEANT4 physics processes were unable to reproduce the experimental observables, while excellent agreement was obtained through the inclusion of the MENATE{sub R} model within GEANT4. The differences between the two approaches are shown to be related to the modeling of the neutron-carbon inelastic reactions. Additionally, the use of MENATE{sub R} provided accurate reproduction of experimental signals associated with neutron scattering within the detector. These results provide validation of the Monte Carlo simulation for modeling measurements of multiple neutrons where the identification and removal of false neutron signals, due to multiple neutron scattering, are required.

  6. Spectral energy distributions of the brightest Palomar-Green quasars at intermediate redshifts

    Science.gov (United States)

    Tripp, Todd M.; Bechtold, Jill; Green, Richard F.

    1994-01-01

    We have combined low-dispersion International Ultraviolet Explorer (IUE) spectra with the optical/near-IR spectrophotometry of Neugebauer et al. (1987) in order to study the spectral energy distributions of seven of the brightest Palomar-Green (PG) quasars at intermediate redshifts (Z(sub em) greater than or equal to 0.9 and less than or equal to 1.5). Some of these PG quasars are barely detectable in long IUE exposures, so we have used the Gaussian Extraction (GEX) technique to maximize the signal-to-noise of the IUE data, and we have co-added all spectra available from the IUE archive for each QSO unless the ultraviolet spectra varied significantly from one exposure to the next. We have corrected the spectral energy distributions for Milky Way reddening using the observed neutral hydrogen column densities on each sight line and the gas-to-dust relation recently derived by Diplas & Savage. Six of the seven quasars are detected down to lambda much less than 700 A in the rest frame, and consequently continuum reddening due to dust in the immediate vicinity of the quasar can have a dramatic effect on the spectral energy distributions. In order to explore the possible importance of intrinsic continuum reddening, we have assembled a heuristic extinction curve which extends to lambda much less than 912 A. Using this heuristic extinction curve, we derive reasonable upper limits on the intrinsic E(B-V) for each quasar. We briefly discuss some of the implications of the derived intrinsic continuum reddening limits. We use geometrically thin accretion disk models to derive the black hole masses and accretion rates implied by the spectral energy distributions. Even if we neglect intrinsic reddening, we find that a large fraction of the quasars require super-Eddington accretion rates (which is not consistent with the thin disk assumption). Comparison of the data in this paper to a large body of data from the literature on the accretion disk M(sub BH) - M dot grid calculated

  7. Fission-fragment angular distributions and total kinetic energies for 235U(n,f) from .18 to 8.83 MeV

    International Nuclear Information System (INIS)

    Meadows, J.W.; Budtz-Joergensen, C.

    1982-01-01

    A gridded ion chamber was used to measure the fission fragment angular distribution and total kinetic energy for the 235 U(n,f) reaction from 0.18 to 8.81 MeV neutron energy. The anisotropies are in generally good agreement with earlier measurements. The average total kinetic energy is approx. 0.2 MeV greater than the thermal value at neutron energies < 2 MeV and shows a sudden decrease of approx. 0.8 MeV between 4 and 5 MeV neutron energy, well below the (n, n'f) threshold. Possible causes of this decrease are a change in the mass distribution or decreased shell effects in the heavy fragment

  8. Angular dependences of the tensor analyzing powers in the dd -> sup 3 Hen reaction at intermediate energies

    CERN Document Server

    Ladygin, V P

    2002-01-01

    The tensor analyzing powers A sub y sub y , A sub x sub x , and A sub x sub z in the dd -> sup 3 Hen reaction at intermediate energies are considered in the framework of the one-nucleon-exchange approximation. Their strong sensitivity to the sup 3 He and deuteron spin structure at short distances is shown

  9. Angular dependences of the tensor analyzing powers in the dd → 3Hen reaction at intermediate energies

    International Nuclear Information System (INIS)

    Ladygin, V.P.; Ladygina, N.B.; )

    2002-01-01

    The tensor analyzing powers A yy , A xx , and A xz in the dd → 3 Hen reaction at intermediate energies are considered in the framework of the one-nucleon-exchange approximation. Their strong sensitivity to the 3 He and deuteron spin structure at short distances is shown [ru

  10. Intermediate steps towards the 2000-Watt society in Switzerland: an energy-economic scenario analysis[Dissertation 17314

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, T. F

    2007-07-01

    In this dissertation by Thorsten Frank Schulz the intermediate steps necessary to realise the 2000-Watt Society in Switzerland are examined. An analysis of an energy-economic scenario shows that the 2000-Watt Society should be seen as a long-term goal. According to the author, the major changes required to allow the implementation of this project concern energy-transformation and energy-demand technologies. Electricity will, according to the author, play an important role in a service-oriented society in the future. In such a transformation even intermediate steps are associated with considerable expense. The aims of the 2000-Watt Society project are listed. Energy and CO{sub 2} balances for the domestic and transport sectors are presented and discussed. Complementary analyses are presented concerning fuel cells and wood-based fuel technologies. Finally, the implications of the 2000-Watt society and the effects of technological change are summarised and an outlook is presented.

  11. A comparative analysis of mechanisms of fast light particles production in nucleus-nucleus collisions at low and intermediate energies

    CERN Document Server

    Denikin, A S

    2002-01-01

    The dynamics and the mechanisms of formation of pre-equilibrium light particles in nucleus-nucleus collisions at low and intermediate energies are discussed in terms of a classical four-body model. The energy and angular distributions of light particles have been calculated. It has been found that at energies lower than 50A MeV the formation of the most high-energy part of the nuclear spectrum occurs at the expense of the acceleration of light target particles with the mean field of the projectile. The obtained data are in good agreement with available experimental data

  12. Physics and chemistry of fission

    International Nuclear Information System (INIS)

    1979-01-01

    Full text: In the pleasant and hospitable atmosphere of the Kernforschungsanlage Juelich in the Federal Republic of Germany, the IAEA symposium on the Physics and Chemistry of Fission took place. Almost 200 scientists attended, 154 abstracts were submitted, and 57 papers presented, but more important than the numbers was the quality of the contributions and the progress reported at the symposium. The neutron was discovered almost 50 years ago; 40 years ago the idea of nuclear fission was born. Since then, a number of laboratories have worked hard to explain the phenomenon of fission One would expect that by now scientists would know exactly what happens in a nucleus before and during the process of fission, particularly as there are hundreds of power and research reactors in operation, and fission of uranium isotopes is the basis of their functioning. At first glance, fission seems a simple process: a neutron hits and penetrates the uranium nucleus which becomes excited, i.e. has a surplus of energy. One way to get rid of this energy is for the nucleus to split into two parts; additional products of this process are energy and more neutrons. Nature, however, seems to dislike such straightforward explanations. In the case of fission, scientists have observed a number of phenomena which disagree with a simple model. Sometimes, a nucleus will split into two parts without being 'attacked' by a neutron; this spontaneous fission opens up a new line of fission research and several contributions at the symposium reported on sophisticated experiments designed to unravel some of its specific details. Sometimes, a fissioning nucleus will emit another particle: ternary fission has become a powerful tool for studying the properties of nuclei during the fission process. For the scientist, it is fascinating to observe how the nucleus behaves during fission. They invent models which are supposed to reproduce the most probable course of events leading to fission. In one of these

  13. Status of fission product yield data

    International Nuclear Information System (INIS)

    Cuninghame, J.G.

    1978-01-01

    The topics covered in this paper are: (a) cumulative yields in thermal neutron fission and in fast fission up to 14 MeV incident neutron energy, (b) dependence of the yields on incident neutron energy and spectrum, (c) independent yields, (d) charge dispersion and distribution, and (e) yields of light particles from ternary fission. The paper reviews information on these subjects for fission of actinides from 232 Th upwards with special emphasis on data published since the 1973 Bologna FPND Panel, compares data sets, and discusses the gaps still to be found in them. (author)

  14. Feasibility of using intermediate x-ray energies for highly conformal extracranial radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Peng; Yu, Victoria; Nguyen, Dan; Demarco, John; Low, Daniel A.; Sheng, Ke, E-mail: ksheng@mednet.ucla.edy [Department of Radiation Oncology, University of California Los Angeles, California 90095 (United States); Woods, Kaley; Boucher, Salime [RadiaBeam Technologies, Santa Monica, California 90404 (United States)

    2014-04-15

    Purpose: To investigate the feasibility of using intermediate energy 2 MV x-rays for extracranial robotic intensity modulated radiation therapy. Methods: Two megavolts flattening filter free x-rays were simulated using the Monte Carlo code MCNP (v4c). A convolution/superposition dose calculation program was tuned to match the Monte Carlo calculation. The modeled 2 MV x-rays and actual 6 MV flattened x-rays from existing Varian Linacs were used in integrated beam orientation and fluence optimization for a head and neck, a liver, a lung, and a partial breast treatment. A column generation algorithm was used for the intensity modulation and beam orientation optimization. Identical optimization parameters were applied in three different planning modes for each site: 2, 6 MV, and dual energy 2/6 MV. Results: Excellent agreement was observed between the convolution/superposition and the Monte Carlo calculated percent depth dose profiles. For the patient plans, overall, the 2/6 MV x-ray plans had the best dosimetry followed by 2 MV only and 6 MV only plans. Between the two single energy plans, the PTV coverage was equivalent but 2 MV x-rays improved organs-at-risk sparing. For the head and neck case, the 2MV plan reduced lips, mandible, tongue, oral cavity, brain, larynx, left and right parotid gland mean doses by 14%, 8%, 4%, 14%, 24%, 6%, 30% and 16%, respectively. For the liver case, the 2 MV plan reduced the liver and body mean doses by 17% and 18%, respectively. For the lung case, lung V20, V10, and V5 were reduced by 13%, 25%, and 30%, respectively. V10 of heart with 2 MV plan was reduced by 59%. For the partial breast treatment, the 2 MV plan reduced the mean dose to the ipsilateral and contralateral lungs by 27% and 47%, respectively. The mean body dose was reduced by 16%. Conclusions: The authors showed the feasibility of using flattening filter free 2 MV x-rays for extracranial treatments as evidenced by equivalent or superior dosimetry compared to 6 MV plans

  15. The SOFIA experiment: Measurement of 236U fission fragment yields in inverse kinematics

    Directory of Open Access Journals (Sweden)

    Grente L.

    2016-01-01

    Full Text Available The SOFIA (Studies On FIssion with Aladin experiment aims at measuring fission-fragments isotopic yields with high accuracy using inverse kinematics at relativistic energies. This experimental technique allows to fully identify the fission fragments in nuclear charge and mass number, thus providing very accurate isotopic yields for low energy fission of a large variety of fissioning systems. This report focuses on the latest results obtained with this set-up concerning electromagnetic-induced fission of 236U.

  16. Critical validity assessment of theoretical models: charge-exchange at intermediate and high energies

    Science.gov (United States)

    Belkić, Dževad

    1999-06-01

    Exact comprehensive computations are carried out by means of four leading second-order approximations yielding differential cross sections dQ/ dΩ for the basic charge exchange process H ++H(1s)→H(1s)+H + at intermediate and high energies. The obtained extensive set of results is thoroughly tested against all the existing experimental data with the purpose of critically assessing the validity of the boundary corrected second-Born (CB2), continuum-distorted wave (CDW), impulse approximation (IA) and the reformulated impulse approximation (RIA). The conclusion which emerges from this comparative study clearly indicates that the RIA agrees most favorably with the measurements available over a large energy range 25 keV-5 MeV. Such a finding reaffirms the few-particle quantum scattering theory which imposes several strict conditions on adequate second-order methods. These requirements satisfied by the RIA are: (i) normalisations of all the scattering wave functions, (ii) correct boundary conditions in both entrance and exit channels, (iii) introduction of a mathematically justified two-center continuum state for the sum of an attractive and a repulsive Coulomb potential with the same interaction strength, (iv) inclusion of the multiple scattering effects neglected in the IA, (v) a proper description of the Thomas double scattering in good agreement with the experiments and without any unobserved peak splittings. Nevertheless, the performed comparative analysis of the above four approximations indicates that none of the methods is free from some basic shortcomings. Despite its success, the RIA remains essentially a high-energy model like the other three methods under study. More importantly, their perturbative character leaves virtually no room for further systematic improvements, since the neglected higher-order terms are prohibitively tedious for practical purposes and have never been computed exactly. To bridge this gap, we presently introduce the variational Pad

  17. Critical validity assessment of theoretical models: charge-exchange at intermediate and high energies

    International Nuclear Information System (INIS)

    Belkic, Dzevad

    1999-01-01

    Exact comprehensive computations are carried out by means of four leading second-order approximations yielding differential cross sections dQ/dΩ for the basic charge exchange process H + +H(1s)→H(1s)+H + at intermediate and high energies. The obtained extensive set of results is thoroughly tested against all the existing experimental data with the purpose of critically assessing the validity of the boundary corrected second-Born (CB2), continuum-distorted wave (CDW), impulse approximation (IA) and the reformulated impulse approximation (RIA). The conclusion which emerges from this comparative study clearly indicates that the RIA agrees most favorably with the measurements available over a large energy range 25 keV-5 MeV. Such a finding reaffirms the few-particle quantum scattering theory which imposes several strict conditions on adequate second-order methods. These requirements satisfied by the RIA are: (i) normalisations of all the scattering wave functions, (ii) correct boundary conditions in both entrance and exit channels, (iii) introduction of a mathematically justified two-center continuum state for the sum of an attractive and a repulsive Coulomb potential with the same interaction strength, (iv) inclusion of the multiple scattering effects neglected in the IA, (v) a proper description of the Thomas double scattering in good agreement with the experiments and without any unobserved peak splittings. Nevertheless, the performed comparative analysis of the above four approximations indicates that none of the methods is free from some basic shortcomings. Despite its success, the RIA remains essentially a high-energy model like the other three methods under study. More importantly, their perturbative character leaves virtually no room for further systematic improvements, since the neglected higher-order terms are prohibitively tedious for practical purposes and have never been computed exactly. To bridge this gap, we presently introduce the variational Pade

  18. Singlet-to-triplet intermediates and triplet exciton dynamics in pentacene thinfilms

    Science.gov (United States)

    Thorsmolle, Verner; Korber, Michael; Obergfell, Emanuel; Kuhlman, Thomas; Campbell, Ian; Crone, Brian; Taylor, Antoinette; Averitt, Richard; Demsar, Jure

    Singlet-to-triplet fission in organic semiconductors is a spin-conserving multiexciton process in which one spin-zero singlet excitation is converted into two spin-one triplet excitations on an ultrafast timescale. Current scientific interest into this carrier multiplication process is largely driven by prospects of enhancing the efficiency in photovoltaic applications by generating two long-lived triplet excitons by one photon. The fission process is known to involve intermediate states, known as correlated triplet pairs, with an overall singlet character, before being interchanged into uncorrelated triplets. Here we use broadband femtosecond real-time spectroscopy to study the excited state dynamics in pentacene thin films, elucidating the fission process and the role of intermediate triplet states. VKT and AJT acknowledge support by the LDRD program at Los Alamos National Laboratory and the Department of Energy, Grant No. DE-FG02-04ER118. MK, MO and JD acknowledge support by the Alexander von Humboldt Foundation.

  19. An experimental investigation on reduced radiological penumbra for intermediate energy x-rays: Implications for small field radiosurgery

    Science.gov (United States)

    Keller, Brian Michael

    Current day external beam radiation therapy typically uses x-ray energies in the megavoltage (6--18 MV) or in the superficial/orthovoltage (80--350 kVp) energy ranges. It has been found that intermediate energy x-rays (those greater than orthovoltage but sub-megavoltage) may offer an advantage in the field of high precision radiation therapy such as in radiosurgery. This advantage is a reduction in the radiological penumbra associated with small (less than about 3 cm) radiation dose fields. A consequence of reduced radiological penumbra is a more homogenous, conformal dose distribution in the patient with dose escalation and organ sparing made more feasible. The objectives of this thesis were as follows: to produce and to characterize an intermediate energy x-ray beam, to establish a method of accurate penumbra measurement at the micron level for millimeter size fields, to measure the radiological penumbra of single small intermediate energy x-ray fields, and to show the clinical consequences of a multiple beam irradiation in a stereotactic head phantom. A maximum photon energy of 1.2 +/- 0.1 MeV was determined for the intermediate energy x-ray spectrum at the expense of a low dose rate. A digital microscope with a computer controlled translation stage was investigated for its ability to resolve steep dose gradients in Gafchromic EBT film for field sizes as small as 1 mm and for photon energies as low as 100 kVp. The microscope-film system resolved gradients to within about 30 mum, limited by the inherent spatial resolution of the film, the noise of the system, and the uncertainties of measurement. Penumbra widths were compared for 1.2 MV versus 6 MV for identical irradiation conditions. In some instances, there was a five-fold reduction in the radiological penumbra of single 1.2 MV x-ray beams. A multiple beam arc irradiation demonstrated that the advantages seen with single beams carry over to multiple beams. The benefits of reduced radiological penumbra for

  20. On the Potential of Nuclear Fission Energy for Effective Reduction of Carbon Emission under the Constraint of Uranium Resources Use without Spent Fuel Reprocessing

    International Nuclear Information System (INIS)

    Knapp, V.; Pevec, D.; Matijevic, M.

    2010-01-01

    Urgency to stop further increase of greenhouse gases emissions and reverse the trends, as stated in the Fourth Intergovernmental Panel on Climate Change (IPPC) Report and in Copenhagen discussions, limits the realistic choice of energy technologies to those available now or in the near future of few decades. In the coming fifty years neither nuclear fusion nor carbon capture and storage (CCS) can be expected to give a significant contribution to world energy production. Two perspective intermittent sources such as wind and solar together with nuclear fission energy covering the base load consumption appears to be a combination with a potential to produce a large share of carbon free energy in the total world energy production. This contribution considers the issues, associated with required large scale deployment of nuclear fission energy. A serious question associated with nuclear energy is nuclear proliferation. Spread of uranium enrichment and spent fuel reprocessing installations in many new countries constructing nuclear reactors would be a major concern in present political environment. We investigate whether uranium resources would be sufficient to support nuclear build-up in next 50-60 years sufficiently large to significantly reduce carbon emission without reprocessing of spent nuclear fuel. A positive answer would mean that 50-60 years can be available to develop effective international control of nuclear fuel cycle installations. Our results show that a maximum nuclear build-up which would consume currently estimated uranium resources by 2065 without reprocessing could reduce by 2065 carbon emission by 39.6% of the total reduction needed to bring the WEO 2009 Reference Scenario prediction of total GHG emissions in 2065 to the level of the WEO 450 Scenario limiting global temperature increase to 2 degrees of C. The less demanding strategy of the nuclear replacement of all non-CCS coal power plants retiring during the 2025-2065 period would reduce emission

  1. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    2015-08-02

    Aug 2, 2015 ... The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped ...

  2. Heavy Ion Physics at Low, Intermediate and Relativistic Energies using 4π Detectors. Proceedings of International Research Workshop

    International Nuclear Information System (INIS)

    Petrovici, M.; Sandulescu, A.; Pelte, D.; Stoecker, H.; Randrup, J.

    1997-01-01

    This monograph contains 37 communications presented at the International Research Workshop held at Poiana Brasov, Romania on October 7-14, 1996. The main subject was heavy ion reactions at low, intermediate and relativistic energies using 4π detectors. The following topics were focussed on: cold fragmentation of nuclear matter, preequilibrium and thermalization, thermal and chemical equilibrium, fragmentation and correlations in intermediate energy collisions, dynamical properties of hot and dense nuclear matter, in-medium effects, resonance and strange nuclear matter, signals of the deconfined state. The dynamical aspects and their role in triggering the liquid-gas phase transition at intermediate energies and the deconfined quark-gluon plasma at ultra-relativistic energies were of special interest. New experimental and theoretical results, illustrating the progress made during the last years in understanding the properties of nuclear matter in extreme conditions of pressure and temperature produced by heavy ion collisions, were presented and intensively discussed. The round table discussion, the last session of the Workshop, summarized through lively and extensive contributions the main subjects attacked during the Workshop. At the end the discussion focussed on the most important question, what strategy the nuclear physics community should embark on at this turn of the millennium

  3. Fission fragment angular distributions and fission cross section validation

    International Nuclear Information System (INIS)

    Leong, Lou Sai

    2013-01-01

    The present knowledge of angular distributions of neutron-induced fission is limited to a maximal energy of 15 MeV, with large discrepancies around 14 MeV. Only 238 U and 232 Th have been investigated up to 100 MeV in a single experiment. The n-TOF Collaboration performed the fission cross section measurement of several actinides ( 232 Th, 235 U, 238 U, 234 U, 237 Np) at the n-TOF facility using an experimental set-up made of Parallel Plate Avalanche Counters (PPAC), extending the energy domain of the incident neutron above hundreds of MeV. The method based on the detection of the 2 fragments in coincidence allowed to clearly disentangle the fission reactions among other types of reactions occurring in the spallation domain. I will show the methods we used to reconstruct the full angular resolution by the tracking of fission fragments. Below 10 MeV our results are consistent with existing data. For example in the case of 232 Th, below 10 MeV the results show clearly the variation occurring at the first (1 MeV) and second (7 MeV) chance fission, corresponding to transition states of given J and K (total spin and its projection on the fission axis), and a much more accurate energy dependence at the 3. chance threshold (14 MeV) has been obtained. In the spallation domain, above 30 MeV we confirm the high anisotropy revealed in 232 Th by the single existing data set. I'll discuss the implications of this finding, related to the low anisotropy exhibited in proton-induced fission. I also explore the critical experiments which is valuable checks of nuclear data. The 237 Np neutron-induced fission cross section has recently been measured in a large energy range (from eV to GeV) at the n-TOF facility at CERN. When compared to previous measurements, the n-TOF fission cross section appears to be higher by 5-7 % beyond the fission threshold. To check the relevance of n-TOF data, we simulate a criticality experiment performed at Los Alamos with a 6 kg sphere of 237 Np. This

  4. More detailed study of fission dynamics in fusion-fission reactions within a stochastic approach

    Science.gov (United States)

    Nadtochy, P. N.; Adeev, G. D.; Karpov, A. V.

    2002-06-01

    A stochastic approach based on three-dimensional Langevin equations was applied to a more detailed study of fission dynamics in fusion-fission reactions. The dynamical model has been developed and extended to investigate fission characteristics of light fissioning nuclei at low excitation energies. The energy dependences of an anisotropy of the fission fragment angular distribution, an evaporation residue cross section, a fission cross section, mean prescission neutron, and giant dipole γ multiplicities have been analyzed for the 16O+208Pb-induced fission of 224Th. Also, dependence of the prescission neutron multiplicity on the fragment mass asymmetry and total kinetic energy have been calculated. Analysis of the results shows that not only characteristics of the mass-energy distribution of fission fragments, but also the mass and kinetic-energy dependence of the prescission neutron multiplicity, the angular anisotropy, and fission probability can be reproduced using a modified one-body mechanism for nuclear dissipation with a reduction coefficient of the contribution from a wall formula ks=0.25 0.5 for compound nuclei 172Yb, 205Fr, 215Fr, and 224Th. Decrease of the prescission neutron multiplicities with fragment mass asymmetry is due to a decrease of the fission time. The results obtained show that prescission neutrons are evaporated predominantly from the nearly spherical compound nucleus at an early stage of fission process before the saddle point is reached. From performed analysis one can conclude that coordinate-independent reduction coefficient ks is not compatible with simultaneous description of the main fission characteristics for heavy fissioning systems 256Fm and 252Fm.

  5. Maruhn-Greiner Maximum of Uranium Fission for Confirmation of Low Energy Nuclear Reactions LENR via a Compound Nucleus with Double Magic Numbers

    Science.gov (United States)

    Hora, H.; Miley, G. H.

    2007-12-01

    One of the most convincing facts about LENR due to deuterons of very high concentration in host metals as palladium is the measurement of the large scale minimum of the reaction probability depending on the nucleon number A of generated elements at A = 153 where a local maximum was measured. This is similar to the fission of uranium at A = 119 where the local maximum follows from the Maruhn-Greiner theory if the splitting nuclei are excited to about MeV energy. The LENR generated elements can be documented any time after the reaction by SIMS or K-shell X-ray excitation to show the very unique distribution with the local maximum. An explanation is based on the strong Debye screening of the Maxwellian deuterons within the degenerate rigid electron background especially within the swimming electron layer at the metal surface or at interfaces. The deuterons behave like neutrals at distances of about 2 picometers. They may form clusters due to soft attraction in the range above thermal energy. Clusters of 10 pm diameter may react over long time probabilities (megaseconds) with Pd nuclei leading to a double magic number compound nucleus which splits like in fission to the A = 153 element distribution.

  6. Dynamical excitation in fission

    International Nuclear Information System (INIS)

    Ledergerber, T.; Paltiel, Z.; Fraenkel, Z.; Pauli, H.C.

    1976-01-01

    The excitation mechanism of the fission process is studied in terms of a model of particles moving in a deformed time-dependent potential. A residual interaction of the pairing type is incoporated by means of the BCS approximation. Only 2-quasi-particle excitations up to some cutoff energy are included. The separation of the total excitation energy into intrinsic and translational parts is made at the scission point. The present calculations for 240 Pu show that, in the framework of this model, most of the available energy at scission is transformed into intrinsic excitation energy. However the convergence of the calculated value for the cutoff energy is unsatisfactory and hence a description in terms of a better model space is needed. The fact that very many channels are involved suggests that a statistical treatment may be useful. (author)

  7. True ternary fission in 310126X

    International Nuclear Information System (INIS)

    Banupriya, B.; Vijayaraghavan, K.R.; Balasubramaniam, M.

    2015-01-01

    All possible combinations are minimized by the two dimensional minimization process and minimized with respect to neutron numbers and proton numbers of the fragments. Potential energy is low and Q - value is high at true ternary fission region. It shows that true ternary mode is the dominant mode in the ternary fission of superheavy nuclei. Also, the results show that the fragments with neutron magic numbers are the dominant one in the ternary fission of superheavy nuclei whereas the fragments with proton magic numbers are the dominant one in the ternary fission of heavy nuclei

  8. Very backward π0- and eta0-production by proton projectiles on deuterium target at intermediate energies

    International Nuclear Information System (INIS)

    Berthet, P.; Frascaria, R.; Didelez, J.P.

    1984-01-01

    The production of π 0 and eta 0 mesons in the reactions pd→π 0 tau and pd→eta 0 tau has been studied at very backward angles for kinetic proton energies Tsub(p) ranging from 0.92 to 2.6 GeV. The excitation functions at phisub(π) = phisub(eta) = 180 0 display large structures which might be related to baryonic (Δ and N*) excitations in the intermediate state

  9. Elastic scattering of the intermediate energy kaon mesons on the nuclei and coulomb's effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhenqiu; Kong Lingjiang; Liu Xianhui

    1985-05-01

    In the frame of the eikonal scattering theory, using the basic parameters which are given by the different authors, the elastic scattering of the intermediate energy kaon mesons /sup 12/C and /sup 40/Ca are studied. The Coulomb effect is calculated too. The results are agreement with the experimental data. The Coulombv effect does not only enhance the small angle differential cross section, but also fill up the dip of the differential cross section.

  10. Cumulative fission yield of Ce-148 produced by thermal-neutron fission of U-235

    International Nuclear Information System (INIS)

    Hasan, A.A.

    1984-12-01

    Cumulative fission yield of 148 cesium isotopes and some other fission products produced by thermal-neutron fission of 235 uranium is determined by Germanium/Lithium spectroscopic methods. The measuremets were done at Tsing-Hua open pool reactor using 3 to 4 mg of 93.15% enriched 235 uranium samples. Gamma rays are assigned to the responsible fission products by matching gamma rays energies and half lives. Fission rate is calculated by fission track method. Cumulative fission yields of 148 cesium, 90 krypton, 130 iodine, 144 lanthanum, 89 krypton, 136 xenon, 137 xenon and 140 cesium are calculated. This values are compared with previously predicted values and showed good agreement. 21 Ref

  11. Consultancy on the potential of fusion/fission sub-critical neutron systems for energy production and transmutation. Working material

    International Nuclear Information System (INIS)

    2005-01-01

    The Workshop on Sub-critical Neutron Production held at the University of Maryland and the Eisenhower Institute on 11-13 October 2004 brought together members of fusion, fission and accelerator technical communities to discuss issues of spent fuel, nonproliferation, reactor safety and the use of neutrons for sub-critical operation of nuclear reactors. The Workshop strongly recommended that the fusion community work closely with other technical communities to ensure that a wider range of technical solutions is available to solve the spent fuel problem and to utilize the current actinide inventories. Participants of the Workshop recommended that a follow-on Workshop, possibly under the aegis of the IAEA, should be held in the first half of the year 2005. The Consultancy Meeting is the response to this recommendation. The objectives of the Consultancy meeting were to hold discussions on the role of fusion/fission systems in sub-critical operations of nuclear reactors. The participants agreed that development of innovative (fourth generation) fission reactors, advanced fuel cycle options, and disposition of existing spent nuclear fuel inventories in various Member Sates can significantly benefit from including sub-critical systems, which are driven by external neutron sources. Spallation neutrons produced by accelerators have been accepted in the past as the means of driving sub-critical reactors. The accelerator community deserves credit in pioneering this novel approach to reactor design. Progress in the design and operation of fusion devices now offers additional innovative means, broadening the range of sub-critical operations of fission reactors. Participants felt that fusion should participate with accelerators in providing a range of technical options in reactor design. Participants discussed concrete steps to set up a small fusion/fission system to demonstrate actinide burning in the laboratory and what advice should be given to the Agency on its role in

  12. Asymmetric Fission in the 78Kr+40Ca reactions at 5.5 MeV/nucleon

    Directory of Open Access Journals (Sweden)

    Roy R.

    2012-02-01

    Full Text Available The cross section, kinetic energy distribution and angular distribution of fragments with atomic number 3 ≤ Z ≤ 28 emitted in the reaction 78Kr + 40Ca at the bombarding energy of 5.5 MeV/nucleon and coincidence between light charged particles and fragments were measured by means of the 4π-INDRA array to study the decay mechanism of medium mass excited nucleus. Global features indicate a high degree of relaxation and are compatible with a binary fission from compound nucleus. The mean value of the kinetic energy distributions of fragments indicates dominance of Coulomb interaction, while the width of the distribution signals large fluctuations. Inclusive cross-section distributions of fragments with charge 3 ≤ Z ≤ 28 are bell-shaped and a strong even-odd-staggering (o-es is observed for 3 ≤ Z ≤ 12. Coincidence measurements suggest that the light partners in very asymmetric fission are emitted at excitation energies below the particle emission thresholds. Data were confronted to the predictions of statistical model describing the decay of compound nuclei by emission of light particles and fragments. Calculations assuming spherical fission fragments and finite-range liquid drop fission barriers are not able to explain the experimental features. Attempts have been made to improve the agreement with experimental data. The analysis indicates the strong influence of the shape parameterization of the potential energy surface in describing the fission process of intermediate mass compound nuclei.

  13. Non-electrical uses of thermal energy generated in the production of fissile fuel in fusion--fission reactors: a comparative economic parametric analysis for a hybrid with or without synthetic fuel production

    International Nuclear Information System (INIS)

    Tai, A.S.; Krakowski, R.A.

    1979-01-01

    A parametric analysis has been carried out for testing the sensitivity of the synfuel production cost in relation to crucial economic and technologic quantities (investment costs of hybrid and synfuel plant, energy multiplication of the fission blanket, recirculating power fraction of the fusion driver, etc.). In addition, a minimum synfuel selling price has been evaluated, from which the fission--fusion--synfuel complex brings about a higher economic benefit than does the fusion--fission hybrid entirely devoted to fissile-fuel and electricity generation. Assuming an electricity cost of 2.7 cents/kWh, an annual investment cost per power unit of 4.2 to 6 $/GJ (132 to 189 k$/MWty) for the fission--fusion complex and 1.5 to 3 $/GJ (47 to 95 k$/MWty) for the synfuel plant, the synfuel production net cost (i.e., revenue = cost) varies between 6.5 and 8.6 $/GJ. These costs can compete with those obtained by other processes (natural gas reforming, resid partial oxidation, coal gasification, nuclear fission, solar electrolysis, etc.). This study points out a potential use of the fusion--fission hybrid other than fissile-fuel and electricity generation

  14. Seventy-five years of nuclear fission

    Indian Academy of Sciences (India)

    the angular distribution of the fragments with the direction of the incident projectile caus- ing fission will depend on .... But in harnessing nuclear energy through the critical fission reactors, disposal of nuclear waste ... experimental technique based on a gridded ion chamber, emission spectra and angular distributions of the ...

  15. Development of Si-based detectors for intermediate energy heavy-ion physics at a storage-ring accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Whitlow, H.J.; Jaworowski, J.; Leandersson, M.; El Bouanani, M. [Lund Institute of Technology, Solvegatan Lund, (Sweden). Department of Nuclear Physics; Jakobsson, B. [Lund Univ. (Sweden). Dept. of Cosmic and Subatomic Physics; Romanski, J.; Westerberg, L.; Van Veldhuizen, E.J. [Uppsala Univ. (Sweden); The Chicsi Collaboration

    1996-12-31

    Ultrahigh vacuum (UHV) compatible Si detectors are being developed by the CELSIUS Heavy lon Collaboration (CHIC) for measuring the energy and identity of Intermediate Mass Fragments (IMF) with Z {approx} 3 - 12 and energies of 0.7 - I 0 A MeV. Here we give an overview of the development of Si {delta}E-E detector telescopes and investigations on IMF identification based on the pulse shape from Si-detectors where the particles impinge on the rear-face of the detector. 9 refs., 4 figs.

  16. Charge Dependence and Electric Quadrupole Effects on Single-Nucleon Removal in Relativistic and Intermediate Energy Nuclear Collisions

    Science.gov (United States)

    Norbury, John W.

    1992-01-01

    Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

  17. Measurement of the average number of prompt neutrons emitted per fission of 235U relative to 252Cf for the energy region 500 eV to 10 MeV

    International Nuclear Information System (INIS)

    Gwin, R.; Spencer, R.R.; Ingle, R.W.; Todd, J.H.; Weaver, H.

    1980-01-01

    The average number of prompt neutrons emitted per fission ν/sub p/-bar(E), was measured for 235 U relative to ν/sub p/-bar for the spontaneous fission of 252 Cf over the neutron energy range from 500 eV to 10 MeV. The samples of 235 U and 252 Cf were contained in fission chambers located in the center of a large liquid scintillator. Fission neutrons were detected by the large liquid scintillator. The present values of ν/sub p/-bar(E) for 235 U are about 0.8% larger than those measured by Boldeman. In earlier work with the present system, it was noted that Boldeman's value of ν/sub p/-bar(E) for thermal energy neutrons was about 0.8% lower than obtained at ORELA. It is suggested that the thickness of the fission foil used in Boldeman's experiment may cause some of the discrepancy between his and the present values of ν/sub p/-bar(E). For the energy region up to 700 keV, the present values of ν/sub p/-bar(E) for 235 U agree, within the uncertainty, with those given in ENDF/B-V. Above 1 MeV the present results for ν/sub p/-bar(E) range about the ENDF/B-V values with differences up to 1.3%. 6 figures, 1 table

  18. Fission fragment mass distributions via prompt γ-ray spectroscopy

    Indian Academy of Sciences (India)

    2015-07-24

    Jul 24, 2015 ... The distribution of fragment masses formed in nuclear fission is one of the most striking features of the process. Such measurements are very important to understand the shape evolution of the nucleus from ground state to scission through intermediate saddle points. The fission fragment mass distributions, ...

  19. Fission fragment mass distributions via prompt γ-ray spectroscopy

    Indian Academy of Sciences (India)

    Abstract. The distribution of fragment masses formed in nuclear fission is one of the most strik- ing features of the process. Such measurements are very important to understand the shape evolu- tion of the nucleus from ground state to scission through intermediate saddle points. The fission fragment mass distributions ...

  20. Detection system with a large angular acceptance and an energy high dynamics, for heavy ion physics at intermediate energies: M.E.ω. detector

    International Nuclear Information System (INIS)

    Monnet, F.

    1985-01-01

    Built for intermediate energy heavy ions nuclear physics, the M.E.ω. detector uses various and complementary detection methods: ionization chamber, parallel plate avalanche counter, plastic scintillators. With these techniques, velocity, energy, mass and charge of nuclei were measured over wide range. From the detailed theoretical study of each method, limitations and perturbation causes are deduced. The solutions used for optimizing the detector, and the main results are exposed. The internal sectorisation of the detector, which permits a modulation in counting rate and electronical adjustments, has been revealed to be very suitable for heavy ions intermediate energy physics. Results of the first experiment realised with M.E.ω. (Ar + Ag at 35 MeV/u) are commented [fr

  1. Fusion-fission studies on 19F+206,208Pb and 11B,19F+238U reactions around barrier energies at IUAC facility

    Science.gov (United States)

    Pullanhiotan, Sugathan; Dubey, Rakesh; Yadav, Chandrabhan; Jhingan, Akhil; Komalan Satheedas, Golda; Nedumbally, Saneesh; Kumar, Mohit

    2017-11-01

    Fission process is strongly influenced by entrance channel dynamical variables. Among these, the nuclear charge product, mass asymmetry and deformation play important role in fission dynamics. Reaction characteristics are distinguished by investigating the properties of fission mass and angular distributions. Experiments using actinide targets are challenging due to many conflicting results making unambiguous identification of quasi-fission difficult. At IUAC accelerator facility many experiments have been performed to make a systematic study of fission mechanism and role of entrance channel parameters and deformation. Fragment mass distribution, angular distribution and neutron multiplicity measurements are performed to study reactions using spherical and deformed targets.

  2. Fission products collecting devices

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshi

    1979-01-01

    Purpose: To enable fission products trap with no contamination to coolants and cover gas by the provision of a fission products trap above the upper part of a nuclear power plant. Constitution: Upon fuel failures in a reactor core, nuclear fission products leak into coolants and move along the flow of the coolants to the coolants above the reactor core. The fission products are collected in a trap container and guided along a pipeline into fission products detector. The fission products detector monitors the concentration of the fission products and opens the downstream valve of the detector when a predetermined concentration of the fission products is detected to introduce the fission products into a waste gas processing device and release them through the exhaust pipe. (Seki, T.)

  3. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies: Annual progress report, 1988--1989

    International Nuclear Information System (INIS)

    1988-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988 under a grant from the US Department of Energy. The nucleon-nucleon research has involved studies of interactions between polarized neutrons and polarized protons. Its purpose is to help complete the determination of the nucleon-nucleon amplitudes at energies up to 800 MeV, as part of a program currently in progress at LAMPF, as well as to investigate the possibility of the existence of dibaryon resonances. The pion-nucleus research involves studies of this interaction in regions where it has not been adequately explored. These include experiments on elastic and double charge exchange scattering at energies above the /Delta/(1232) resonance, interactions with polarized nuclear targets, and investigations of pion absorption using a detector covering nearly the full solid angle region. 21 refs., 4 figs

  4. Fissionable material

    International Nuclear Information System (INIS)

    Schuuring, C.; Tuininga, E.-J.; Turkenburg, W.

    1983-01-01

    This book is a presentation of controversies surrounding nuclear energy discussions in the Netherlands and aims to show that there are serious arguments against nuclear energy. Chapters on the following topics are included: the various dimensions of the energy discussion, the background to the existence of controversies in the nuclear energy discussion, the relation between nuclear energy and prosperity, different opinions concerning the cost of producing electricity from nuclear energy, radioactive waste, the consequences of a large scale accident, the relation between the peaceful use of nuclear energy and the proliferation of nuclear weapons, the effects of low radiation doses, the relation between nuclear energy and developments in the Third World, the effect of nuclear energy on democracy. The authors of these chapters, themselves critical of nuclear energy, have described the particular controversy and have given the viewpoints of both advocates and adversaries, followed by their own opinion. The conclusions from each chapter are recapitulated in a summary and the various components of the nuclear energy cycle are presented in an appendix. (C.F.)

  5. Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium. [Wave functions, preliminary experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rolfe, R.M.

    1976-12-01

    The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed.

  6. Nuclear fission studies: from LOHENGRIN to FIPPS

    International Nuclear Information System (INIS)

    Chebboubi, Abdelaziz

    2015-01-01

    Nuclear fission consists in splitting a nucleus, in general an actinide, into smaller nuclei. Despite nuclear fission was discovered in 1939 by Hahn and Strassman, fission models cannot predict the fission observables with an acceptable accuracy for nuclear fuel cycle studies for instance. Improvement of fission models is an important issue for the knowledge of the process itself and for the applications. To reduce uncertainties of the nuclear data used in a nuclear reactor simulation, a validation of the models hypothesis is mandatory. In this work, two features of the nuclear fission were investigated in order to test the resistance of the theories. One aspect is the study of the symmetric fission fragments through the measurement of their yield and kinetic energy distribution. The other aspect is the study of the fission fragment angular momentum.Two techniques are available to assess the angular momentum of a fission fragment. The first one is to look at the properties of the prompt gamma. The new spectrometer FIPPS (Fission Product Prompt gamma-ray Spectrometer), is currently under development at the ILL and will combine a fission filter with a large array of gamma and neutron detectors in order to respond to these issues. The first part of this work is dedicated to the study of the properties of a Gas Filled Magnet (GFM) which is the type of fission filter considered for the FIPPS project.The second part of this work deals with the measurement of isomeric yields and evaluations of the angular momentum distribution of fission fragments. The study of the spherical nucleus 132 Sn shed the light on the current limits of fission models. Finally, the last part of this work is about the measurement of the yields and kinetic energy distributions of symmetric fission fragments. Since models predict the existence of fission modes, the symmetry region is a suitable choice to investigate this kind of prediction. In parallel with all these studies, an emphasis on the

  7. Change over from compound nuclear fission to quasi-fission

    International Nuclear Information System (INIS)

    Ghosh, T. K.; Banerjee, K.; Bhattacharya, C.; Bhattacharya, S.; Kundu, S.; Meena, J. K.; Mukherjee, G.; Mukhopadhyay, S.; Rana, T. K.; Golda, K. S.; Bhattacharya, P.

    2010-01-01

    Fission fragment mass distribution has been measured from the decay of 246 Bk nucleus populating via two entrance channels with slight difference in mass asymmetries but belonging on either side of the Businaro Gallone mass asymmetry parameter. Both the target nuclei were deformed. Near the Coulomb barrier, at similar excitation energies the width of the fission fragment mass distribution was found to be drastically different for the 14 N+ 232 Th reaction compared to the 11 B+ 235 U reaction. The entrance channel mass asymmetry was found to affect the fusion process sharply. (authors)

  8. Change over from compound nuclear fission to quasi-fission

    Directory of Open Access Journals (Sweden)

    Bhattacharya P.

    2010-03-01

    Full Text Available Fission fragment mass distribution has been measured in two reactions to populate compound nucleus 246Bk. Both the target nuclei were deformed. However, entrance channel mass asymmetry of the two systems was on the either side of the Businaro Gallone mass asymmetry parameter. Near the Coulomb barrier, at similar excitation energies, the width of the fission fragment mass distribution was found to be significantly different for the 14N+232Th reaction compared to the 11B+235U reaction. The entrance channel mass asymmetry was found to play a significant role in deciding the fusion process.

  9. Fission barrier heights in the A ∼ 200 mass region

    Indian Academy of Sciences (India)

    Abstract. Statistical model analysis is carried out for p- and α-induced fission reactions using a consistent description for fission barrier and level density in A ∼ 200 mass region. A continuous damping of shell correction with excitation energy is considered. Extracted fission barriers agree well with the recent ...

  10. Charged particle-induced nuclear fission reactions – Progress and ...

    Indian Academy of Sciences (India)

    of fission process for nuclei at moderately high excitation energies with large angular momentum values. ... model analysis of these data, the fission barrier can be determined for the fissioning com- pound nucleus. .... qualitative understanding of the various features of mass division are understood in terms of scission point ...

  11. Fission barrier heights in the A∼ 200 mass region

    Indian Academy of Sciences (India)

    2015-07-19

    Jul 19, 2015 ... Statistical model analysis is carried out for - and -induced fission reactions using a consistent description for fission barrier and level density in A ∼ 200 mass region. A continuous damping of shell correction with excitation energy is considered. Extracted fission barriers agree well with the recent ...

  12. Fusion-fission study at IUAC: Recent results

    Science.gov (United States)

    Pullanhiotan, Sugathan

    2016-10-01

    Several properties observed in heavy ion induced fission led to the conclusion that fission is not always originated from fully equilibrated compound nucleus. Soon after the collision of two nuclei, it forms a di-nuclear system than can fission before a compound nucleus is formed. This process termed quasi-fission is a major hurdle to the formation of heavier elements by fusion. Fission originated before complete equilibration showed anomalously large angular anisotropy and mass distribution wider than what is expected from compound nucleus fission. The standard statistical model fails to predict the outcome of quasi-fission and currently no dynamical model is fully developed to predict all the features of quasi-fission. Though much progress has been made in recent times, a full understanding of the fission dynamics is still missing. Experiments identifying the influence of entrance channel parameters on dynamics of fusion-fission showed contrasting results. At IUAC accelerator facility many experiments have been performed to make a systematic study of fission dynamics using mass distribution, angular distribution and neutron multiplicity measurements in mass region around A ∼ 200. Recent measurement on mass distribution of fission fragment from reaction 19 F +206,208 Pb around fusion barrier energy showed the influence of multi-mode fission in enhancing the mass variance at low excitation energy. In this talk I will present some of these results.

  13. Monte carlo sampling of fission multiplicity.

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, J. S. (John S.)

    2004-01-01

    Two new methods have been developed for fission multiplicity modeling in Monte Carlo calculations. The traditional method of sampling neutron multiplicity from fission is to sample the number of neutrons above or below the average. For example, if there are 2.7 neutrons per fission, three would be chosen 70% of the time and two would be chosen 30% of the time. For many applications, particularly {sup 3}He coincidence counting, a better estimate of the true number of neutrons per fission is required. Generally, this number is estimated by sampling a Gaussian distribution about the average. However, because the tail of the Gaussian distribution is negative and negative neutrons cannot be produced, a slight positive bias can be found in the average value. For criticality calculations, the result of rejecting the negative neutrons is an increase in k{sub eff} of 0.1% in some cases. For spontaneous fission, where the average number of neutrons emitted from fission is low, the error also can be unacceptably large. If the Gaussian width approaches the average number of fissions, 10% too many fission neutrons are produced by not treating the negative Gaussian tail adequately. The first method to treat the Gaussian tail is to determine a correction offset, which then is subtracted from all sampled values of the number of neutrons produced. This offset depends on the average value for any given fission at any energy and must be computed efficiently at each fission from the non-integrable error function. The second method is to determine a corrected zero point so that all neutrons sampled between zero and the corrected zero point are killed to compensate for the negative Gaussian tail bias. Again, the zero point must be computed efficiently at each fission. Both methods give excellent results with a negligible computing time penalty. It is now possible to include the full effects of fission multiplicity without the negative Gaussian tail bias.

  14. Physics of neutron emission in fission

    International Nuclear Information System (INIS)

    Lemmel, H.D.

    1989-06-01

    The document contains the proceedings of the IAEA Consultants' Meeting on the Physics of Neutron Emission in Fission, Mito City (Japan), 24-27 May 1988. Included are the conclusions and recommendations reached at the meeting and the papers presented by the meeting participants. These papers cover the following topics: Energy dependence of the number of fission neutrons ν-bar (3 papers), multiplicity distribution of fission neutrons (3 papers), competition between neutron and γ-ray emission (4 papers), the fission neutron yield in resonances (2 papers) and the energy spectrum of fission neutrons in experiment (9 papers), theory (4 papers) and evaluation (1 paper). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  15. Bulk and surface controlled diffusion of fission gas atoms

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders D. [Los Alamos National Laboratory

    2012-08-09

    Fission gas retention and release impact nuclear fuel performance by, e.g., causing fuel swelling leading to mechanical interaction with the clad, increasing the plenum pressure and reducing the gap thermal conductivity. All of these processes are important to understand in order to optimize operating conditions of nuclear reactors and to simulate accident scenarios. Most fission gases have low solubility in the fuel matrix, which is especially pronounced for large fission gas atoms such as Xe and Kr, and as a result there is a significant driving force for segregation of gas atoms to extended defects such as grain boundaries or dislocations and subsequently for nucleation of gas bubbles at these sinks. Several empirical or semi-empirical models have been developed for fission gas release in nuclear fuels, e.g. [1-6]. One of the most commonly used models in fuel performance codes was published by Massih and Forsberg [3,4,6]. This model is similar to the early Booth model [1] in that it applies an equivalent sphere to separate bulk UO{sub 2} from grain boundaries represented by the sphere circumference. Compared to the Booth model, it also captures trapping at grain boundaries, fission gas resolution and it describes release from the boundary by applying timedependent boundary conditions to the circumference. In this work we focus on the step where fission gas atoms diffuse from the grain interior to the grain boundaries. The original Massih-Forsberg model describes this process by applying an effective diffusivity divided into three temperature regimes. In this report we present results from density functional theory calculations (DFT) that are relevant for the high (D{sub 3}) and intermediate (D{sub 2}) temperature diffusivities of fission gases. The results are validated by making a quantitative comparison to Turnbull's [8-10] and Matzke's data [12]. For the intrinsic or high temperature regime we report activation energies for both Xe and Kr diffusion

  16. Delayed β ray spectrum of 235U fission fragments

    International Nuclear Information System (INIS)

    Pascholati, P.R.

    1973-01-01

    The time-dependent electron spectra of fission fragments from the thermal-neutron-induced fission of 235 U are calculated. The Gross theory of nuclear beta decay is used to obtain the decay constant and individual electron spectra. The mean energy per fission carried by the electrons and the number of electrons per fission are also calculated. Comparison of these calculated spectra to experimental ones shows good agreements. (Author) [pt

  17. Mass dependence of positive pion-induced fission

    International Nuclear Information System (INIS)

    Khan, H.A.; Khan, N.A.; Peterson, R.J.

    1991-01-01

    Fission cross sections for a range of targets have been measured by solid-state track detectors following 80 and 100 MeV π + bombardment. Fission probabilities have been inferred by comparison to computed reaction cross sections. Fission probabilities for heavy targets agree with those for other probes of comparable energy and with statistical calculations. Probabilities for lighter targets are much above those previously observed or computed. Ternary fission cross sections and multiplicities of light fragments have also been determined

  18. Neutron emission as a probe of fusion-fission and quasi-fission dynamics

    International Nuclear Information System (INIS)

    Hinde, D.J.

    1991-01-01

    Pre- and post scission neutron yeilds have been measured as a function of projectile mass, compound nucleus fissility, and fission mass-split and total kinetic energy (TKE) for 27 fusion-fission and quasi-fission reactions induced by beams of 16,18 O, 40 Ar and 64 Ni. A new method of interpretation of experimental pre-scission neutron multiplicities ν-pre and mean kinetic energies ε ν allows the extraction of fission time scales with much less uncertainty than previously, all fusion-fission results being consistent with a dynamical time scale of (35±15) x 10 -21 s for symmetric fission. All reactions show that ν-pre falls quite rapidly with increasing mass-asymmetry; evidence is presented that for fusion-fission reactions this is partly due to a reduction of the dynamical fission time scale with mass-asymmetry. For quasi-fission, the data indicate that the pre-scission multiplicity and mean neutron kinetic energy are very sensitive to the final mass-asymmetry, but that the time scale is virtually independent of mass-asymmetry. It is concluded that for fusion-fission there is no dependence of ν-pre on TKE, whilst for 64 Ni-induced quasi-fission reactions, a strong increase of ν-pre with decreasing TKE is observed, probably largely caused by neutron emission during the acceleration time of the fission fragments in these fast reactions. Interpretation of post-scission multiplicities in terms of fragment excitation energies leads to deduced time scales consistent with those determined from the pre-scission data. 54 refs., 17 tabs., 25 figs

  19. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    collaborators [1,2]. The importance of deformed valleys in the potential energy surfaces. (PES) is that they provide the most favoured fission channels for the decay of superheavy nuclei. For the dynamics study, one has to introduce the influence of mass tensor. We use the results from pairing calculations for the occupation ...

  20. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    2015-08-02

    Aug 2, 2015 ... ... nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential.

  1. Search for Singlet Fission Chromophores

    Energy Technology Data Exchange (ETDEWEB)

    Havlas, Z.; Akdag, A.; Smith, M. B.; Dron, P.; Johnson, J. C.; Nozik, A. J.; Michl, J.

    2012-01-01

    Singlet fission, in which a singlet excited chromophore shares its energy with a ground-state neighbor and both end up in their triplet states, is of potential interest for solar cells. Only a handful of compounds, mostly alternant hydrocarbons, are known to perform efficiently. In view of the large number of conditions that a successful candidate for a practical cell has to meet, it appears desirable to extend the present list of high performers to additional classes of compounds. We have (i) identified design rules for new singlet fission chromophores and for their coupling to covalent dimers, (ii) synthesized them, and (iii) evaluated their performance as neat solids or covalent dimers.

  2. Heavy ion induced fission between 10 and 100 MeV/u

    International Nuclear Information System (INIS)

    Steckmeyer, J.C.; Tamain, B.

    1986-05-01

    Heavy ion induced fission between 10 and 100 MeV/u is discussed. It is shown that one can obtain information on fusion limits and on typical times characterizing nuclear matter. Intermediate energy heavy ions can be used to build very excited fusion nuclei. Section I shows that fission can then be used as a tool to test the fusion mechanism and to discover what are the extreme limits concerning fusion and hot nuclei formation. In section II, it is shown that when very hot nuclei are built, fission evaporation competition cannot any longer be fully described in the usual way by the statistical model. New features as dynamical aspects or cluster evaporation modify dramatically the landscape. Concerning the detailed fission properties of very hot nuclei (for instance fragments properties), no strong deviations from the already know systematics has been obtained. However, very few detailed studies are yet available and a clear experimental program has to be developed in order to progress. From a theoretical point of view, it is rather necessary to described fission and evaporation is an unified way

  3. Thorium-uranium fission radiography

    Science.gov (United States)

    Haines, E. L.; Weiss, J. R.; Burnett, D. S.; Woolum, D. S.

    1976-01-01

    Results are described for studies designed to develop routine methods for in-situ measurement of the abundance of Th and U on a microscale in heterogeneous samples, especially rocks, using the secondary high-energy neutron flux developed when the 650 MeV proton beam of an accelerator is stopped in a 42 x 42 cm diam Cu cylinder. Irradiations were performed at three different locations in a rabbit tube in the beam stop area, and thick metal foils of Bi, Th, and natural U as well as polished silicate glasses of known U and Th contents were used as targets and were placed in contact with mica which served as a fission track detector. In many cases both bare and Cd-covered detectors were exposed. The exposed mica samples were etched in 48% HF and the fission tracks counted by conventional transmitted light microscopy. Relative fission cross sections are examined, along with absolute Th track production rates, interaction tracks, and a comparison of measured and calculated fission rates. The practicality of fast neutron radiography revealed by experiments to data is discussed primarily for Th/U measurements, and mixtures of other fissionable nuclei are briefly considered.

  4. The fission cross section ratios and error analysis for ten thorium, uranium, neptunium and plutonium isotopes at 14.74 MeV neutron energy

    International Nuclear Information System (INIS)

    Meadows, J.W.

    1987-03-01

    The error information from the recent measurements of the fission cross section ratios of nine isotopes, 230 Th, 232 Th, 233 U, 234 U, 236 U, 238 U, 237 Np, 239 Pu, and 242 Pu, relative to 235 U at 14.74 MeV neutron energy was used to calculate their correlations. The remaining 36 non-trivial and non-reciprocal cross section ratios and their errors were determined and compared to evaluated (ENDF/B-V) values. There are serious differences but it was concluded that the reduction of three of the evaluated cross sections would remove most of them. The cross sections to be reduced are 230 Th - 13%, 237 Np - 9.6% and 239 Pu - 7.6%. 5 refs., 6 tabs

  5. Determination of the fission-neutron averaged cross sections of some high-energy threshold reactions of interest for reactor dosimetry

    International Nuclear Information System (INIS)

    Arribere, M.A.; Kestelman, A.J.; Korochinsky, S.; Blostein, J.J.

    2003-01-01

    For three high threshold reactions, we have measured the cross sections averaged over a 235 U fission neutron spectrum. The measured reactions, and corresponding averaged cross sections found, are: 127 I(n,2n) 126 I, (1.36±0.12) mb; 90 Zr(n,2n) 89m Zr, (13.86±0.83) μb; and 58 Ni(n,d+np+pn) 57 Co, (274±15) μb; all referred to the well known standard of (111±3) mb for the 58 Ni(n,p) 58m+g Co averaged cross section. The measured cross sections are of interest in nuclear engineering for the characterization of the fast neutron component in the energy distribution of reactor neutrons. (author)

  6. Application of the dinuclear system model to fission process

    Science.gov (United States)

    Andreev, A. V.; Shneidman, T. M.; Ventura, A.

    2016-01-01

    A theoretical evaluation of the collective excitation spectra of nucleus at large deformations is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of nucleons between clusters. In this work the method of calculation of the potential energy and the collective spectrum of fissioning nucleus at scission point is presented. Combining the DNS model calculations and the statistical model of fission we calculate the mass, total kinetic energy, and angular distribution of fission fragments for the neutron-induced fission of 239Pu.

  7. Application of the dinuclear system model to fission process

    Directory of Open Access Journals (Sweden)

    Andreev A. V.

    2016-01-01

    Full Text Available A theoretical evaluation of the collective excitation spectra of nucleus at large deformations is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of nucleons between clusters. In this work the method of calculation of the potential energy and the collective spectrum of fissioning nucleus at scission point is presented. Combining the DNS model calculations and the statistical model of fission we calculate the mass, total kinetic energy, and angular distribution of fission fragments for the neutron–induced fission of 239Pu.

  8. Relative biological efficiency of intermediate energy neutrons and 60Co rays for induction of chromosomal aberrations in Chinese hamster fibroblasts

    International Nuclear Information System (INIS)

    Sturelid, S.; Bergman, R.

    1976-01-01

    Intermediate energy neutrons are unique in that a considerable fraction of critical interactions and of dose absorbed is not associated with ionization but with atomic collision. It is still unknown to what extent the qualitative difference in primary damage after atomic collision compared to that of ionization and excitation becomes expressed at biological levels. Chromosomal aberrations were studied in Chinese hamster fibroblasts exposed for 5-8 hours at 22 degree C to intermediate energy neutrons, mean energy 8.5 keV, or to 60 Co-gamma rays. RBE at the 10 per cent aberration frequency level in S-phase were 2.2+-0.6 for total aberrations, 2.1+-0.6 for chromatid breaks and 1.8+-0.5 for exchanges. For each chromatid aberration observed after recovery, about 200 bondbreaking atomic collisions besides 3000 primary iniozations should have occured in DNA. However, the extent to which the aberration response is due to atomic collisions is not clear. (author)

  9. Fission Research at IRMM

    Directory of Open Access Journals (Sweden)

    Al-Adili A.

    2010-03-01

    Full Text Available Fission Research at JRC-IRMM has a longstanding tradition. The present paper is discussing recent investigations of fission fragment properties of 238 U(n,f, 234 U(n,f, prompt neutron emission in fission of 252 Cf(SF as well as the prompt fission neutron spectrum of 235 U(n,f and is presenting the most important results.

  10. Electron capture in low- and intermediate-energy collisions between completely stripped light ions and metastable H(2s) targets

    International Nuclear Information System (INIS)

    Blanco, S.A.; Falcon, C.A.; Reinhold, C.O.; Casaubon, J.I.; Piacentini, R.D.

    1987-01-01

    Total cross sections for electron capture from H(2s) targets by He 2+ ions have been computed in the impact velocity range 0.05-0.5 au. Calculations were performed using a molecular close-coupling approach with inclusion of electron translation factors. A ten-state molecular basis set was considered. A comparison is made with Landau-Zener results for the same system. Intermediate projectile energy classical Monte Carlo capture cross sections are also presented for H + , He 2+ , Li 3+ and C 6+ projectiles. (author)

  11. Universal fluctuations: a new approach to the study of ''phase transitions'' in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Frankland, J.D.; Chbihi, A.; Hudan, S.

    2002-01-01

    The universal theory of order parameter fluctuations (Δ-scaling laws) is applied to a wide range of intermediate energy heavy-ion collision data obtained with INDRA. This systematic study confirms that the observed fragment production is compatible with aggregation scenarios for in- or out-of-equilibrium continuous phase transitions, while not showing any sign of critical behaviour or phase coexistence. We stress the importance of the methodology employed in order to gain further insight into the mechanism(s) responsible. (authors)

  12. Anomalous Peaklike Structure in the Fission Fragment Anisotropiesat Sub-barrier Energies in {sup 11}B, {sup 12}C, {sup 16}O, {sup 19}F+{sup 232}Th Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, N.; Bhattacharya, P. [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar Calcutta 700 064 (India); Biswas, D.C.; Choudhury, R.K.; Nadkarni, D.M.; Saxena, A. [Bhabha Atomic Research Centre, Bombay 400 085 (India)

    1996-12-01

    Fission fragment angular distributions have been measured for fission following full momentum transfer in {sup 11}B, {sup 12}C, {sup 16}O, and {sup 19}F+{sup 232}Th systems from above barrier to below sub-barrier energies. The fragment anisotropies are found to exhibit an anomalous peaklike structure below the fusion barrier in all the systems. This structure has a universal behavior independent of the entrance channel mass asymmetry. With some refinement in the quasifission hypothesis it is possible to explain qualitatively the experimental results reasonably well. {copyright} {ital 1996 The American Physical Society.}

  13. New fission-neutron-spectrum representation for ENDF

    International Nuclear Information System (INIS)

    Madland, D.G.

    1982-04-01

    A new representation of the prompt fission neutron spectrum is proposed for use in the Evaluated Nuclear Data File (ENDF). The proposal is made because a new theory exists by which the spectrum can be accurately predicted as a function of the fissioning nucleus and its excitation energy. Thus, prompt fission neutron spectra can be calculated for cases where no measurements exist or where measurements are not possible. The mathematical formalism necessary for application of the new theory within ENDF is presented and discussed for neutron-induced fission and spontaneous fission. In the case of neutron-induced fission, expressions are given for the first-chance, second-chance, third-chance, and fourth-chance fission components of the spectrum together with that for the total spectrum. An ENDF format is proposed for the new fission spectrum representation, and an example of the use of the format is given

  14. A Wien filter velocity analyzer for intermediate energy electron impact spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boechat-Roberty, H.M. [Observatorio Nacional do Brasil, Rio de Janeiro, RJ (Brazil); Souza, G.G.B. de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

    1995-09-01

    A new electron velocity analyzer based on the Wien Filter principle, has been developed. In this analyzer an electrical and magnetic field perpendicular to each other, disperse electrons of different energies. Immersion electrostatic lenses are employed, in order to decelerate and accelerate the electrons respectively before and after energy dispersion. This analyzer has demonstrated an excellent capability in the determination of energy-loss spectra in an extended impact energy range (0.2 to 1.5 KeV). The high inherent signal/noise ratio has lead to the acquisition of well-defined and reliable inner-shell excitation spectra. (author). 18 refs.

  15. Fission fragment anisotropy of 235U measured with the fissionTPC

    Science.gov (United States)

    Hensle, David; Greife, Uwe; Niffte Collaboration

    2017-09-01

    The fissionTPC, built for the purpose of making neutron-induced fission cross section measurements with unprecedented precision, is a two-chamber MICROMEGAS time projection chamber that allows for three-dimensional tracking of charged particles. This three-dimensional tracking capability also provides a direct measurement of fission fragment angular distributions for neutron-induced fission. Fragment angular anisotropy is an important experimental observable for understanding the quantum mechanical state of the fissioning nucleus and a parameter required to determine detection efficiency for cross section measurements. Preliminary results for 235U fission fragment anisotropy as a function of neutron energies in the range 130 keV - 100 MeV will be presented.

  16. A revised calculational model for fission

    International Nuclear Information System (INIS)

    Atchison, F.

    1998-09-01

    A semi-empirical parametrization has been developed to calculate the fission contribution to evaporative de-excitation of nuclei with a very wide range of charge, mass and excitation-energy and also the nuclear states of the scission products. The calculational model reproduces measured values (cross-sections, mass distributions, etc.) for a wide range of fissioning systems: Nuclei from Ta to Cf, interactions involving nucleons up to medium energy and light ions. (author)

  17. Nuclear stopping and compression in heavy-ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    Fu Fen; Xiao Zhigang; Zhang, Ya-Peng; Feng Zhaoqing; Jin Genming; Xu Hushan; Yao Nan; Yuan Xiaohua; Zhang Xueying; Zhang Ming

    2008-01-01

    The nuclear stopping and the radial flow are investigated with an isospin-dependent quantum molecular dynamics (IQMD) model for Ni + Ni and Pb + Pb from 0.4 to and 1.2 GeV/u. The expansion velocity as well as the degree of nuclear stopping are higher in the heavier system at all energies. The ratio between the flow energy and the total available energy in center of mass of the colliding systems exhibits a positive correlation to the degree of nuclear stopping. The maximum density (ρ max ) achieved in the compression is comparable to the hydrodynamics prediction only if the non-zero collision time effect is taken into account in the later. Due to the partial transparency, the growing of the maximum density achieved in the central region of the fireball with the increase of beam energy becomes gradually flat in the 1 GeV/u energy regime

  18. Theory of inelastic ion-atom scattering at low and intermediate energies

    Science.gov (United States)

    Schmid, G. B.; Garcia, J. D.

    1977-01-01

    Ab initio calculations are presented of inelastic energy loss and ionization phenomena associated with Ar(+)-Ar collisions at small distances of closest approach and for laboratory collision energies ranging from several keV to several hundred keV. Outer-shell excitations are handled statistically; inner-shell excitations are calculated from the viewpoint of quasidiabatic molecular orbital promotion. Auger electron yield, average state of ionization, and average inelastic energy loss are calculated per collision as a function of distance of closest approach of the collision partners for several laboratory collision energies. Average charge-state probabilities per collision partner are calculated as a function of the average inelastic energy loss per atom. It is shown that the structure in the data is due to the underlying structure in the inner-shell independent-electron quasimolecular promotion probabilities.

  19. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, G.

    1975-01-01

    This is the first issue of a report series on Fission Product Nuclear Data (FPND), published every six months by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). Its purpose is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The types of activities being included in this report are measurements, compilations and evaluations of: fission product yields; neutron cross-section data of fission products; data related to β-, γ-decay of fission products; delayed neutron data; and fission product decay-heat. The present issue includes contributions which were received by NDS before 1 November 1975

  20. Investigation of exotic fission modes

    International Nuclear Information System (INIS)

    Poenaru, D. N.; Gherghescu, R. A.; Greiner, W.; Nagame, Y.; Hamilton, J. H.; Ramayya, A. V.

    2002-01-01

    Fission approach to the cluster radioactivities and α-decay has been systematically developed during the last two decades. A more complex process, the ternary fission, was observed since 1946 both in neutron-induced and spontaneous fission. We obtained interesting results concerning the binary fission saddle-point reflection asymmetric nuclear shapes, and we can explain how a possible nuclear quasimolecular state is formed during the 10 Be accompanied cold fission of 252 Cf. The equilibrium nuclear shapes in fission theory are usually determined by minimizing the deformation energy for a given surface equation. We developed a method allowing to obtain a very general saddle-point shape as a solution of a differential equation without an a priori introduction of a shape parametrization. In the approach based on a liquid drop model (LDM), saddle-point shapes are always reflection symmetric: the deformation energy increases with the mass-asymmetry parameter η = (A 1 - A 2 )/(A 1 + A 2 ). By adding the shell corrections to the LDM deformation energy, we obtained minima at a finite mass asymmetry for parent nuclei 238 U, 232,228 Th in agreement with experiments. This correction was calculated phenomenologically. A technique based on the fragment identification by using triple γ coincidences in the large arrays of Ge-detectors, like GAMMASPHERE, was employed at Vanderbilt University to discover new characteristics of the fission process, and new decay modes. The possibility of a whole family of new decay modes, the multicluster accompanied fission, was envisaged. Besides the fission into two or three fragments, a heavy or superheavy nucleus spontaneously breaks into four, five or six nuclei of which two are asymmetric or symmetric heavy fragments and the others are light clusters, e.g. α-particles, 10 Be, 14 C, or combinations of them. Examples were presented for the two-, three- and four cluster accompanied cold fission of 252 Cf and 262 Rf, in which the emitted

  1. Analysis of α-12C elastic scattering at intermediate energies by the S-matrix model

    Science.gov (United States)

    Berezhnoy, Yu. A.; Onyshchenko, G. M.; Pilipenko, V. V.

    The results of calculations of differential cross-sections for α-12C elastic scattering by the S-matrix model are presented for 10 energy values in the energy range 65MeV ≤ Eα ≤ 386MeV in a wide range of scattering angles. The behavior of various scattering characteristics as functions of the projectile energy is analyzed. It is shown that the chosen parametrization of S-matrix allows describing correctly the Fraunhofer oscillations of the cross-sections in the region of small scattering angles and the rainbow scattering pattern in the region of sufficiently large angles.

  2. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1982-07-01

    This is the eighth issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS. Therefore, the IAEA cannot be held responsible for the information contained nor for any consequences resulting from the use of this information. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The seventh issue of this series has been published in July 1981 as INDC(NDS)-116. The present issue includes contributions which were received by NDS between 1 August 1981 and 15 June 1982

  3. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1983-08-01

    This is the ninth issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The eighth issue of this series has been published in July 1982 as INDC(NDS)-130. The present issue includes contributions which were received by NDS between 1 August 1982 and 25 June 1983

  4. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1981-06-01

    This is the seventh issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission); neutron reaction cross sections of fission products; data related to the radioactive decay of fission products; delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The sixth issue of this series has been published in June 1980 as INDC(NDS)-113/G+P. The present issue includes contributions which were received by NDS between 1 August 1980 and 25 May 1981

  5. Transverse and radial flow in intermediate energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Vestfall, D. Gary

    1997-01-01

    We have studied transverse and radial flow in nucleus-nucleus collisions ranging in energy from 15 to 155 MeV/nucleon. We have measured the impact parameter dependence of the balance energy for Ar + Sc and compared the results with Quantum Molecular Dynamics calculations with and without momentum dependence. We have shown that transverse flow and the balance energy dependence on the isospin of the system using the systems 58 Fe + 58 Fe, 58 Ni + 58 Ni, and 58 Mn + 58 Fe. These results are compared with Boltzmann-Uehling-Uehlenbeck calculations incorporating isospin-dependence. We have measured radial flow for Ar + Sc and find that about 50% of the observed energy is related to radial flow. (author)

  6. An investigation into electron scattering from pyrazine at intermediate and high energies

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, A. G.; Fuss, M. C. [Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid (Spain); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Gorfinkiel, J. D. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Almeida, D.; Ferreira da Silva, F.; Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Brunger, M. J. [ARC Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); García, G., E-mail: g.garcia@iff.csic.es [Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 113-bis, 28006 Madrid (Spain); Centre for Medical Radiation Physics, University of Wollongong, NSW 2522 (Australia)

    2013-11-14

    Total electron scattering cross sections for pyrazine in the energy range 10–500 eV have been measured with a new magnetically confined electron transmission-beam apparatus. Theoretical differential and integral elastic, as well as integral inelastic, cross sections have been calculated by means of a screening-corrected form of the independent-atom representation (IAM-SCAR) from 10 to 1000 eV incident electron energies. The present experimental and theoretical total cross sections show a good level of agreement, to within 10%, in the overlapping energy range. Consistency of these results with previous calculations (i.e., the R-matrix and Schwinger Multichannel methods) and elastic scattering measurements at lower energies, below 10 eV, is also discussed.

  7. Determination of minimum impact parameter by modified touching spheres schemes for intermediate energy Coulomb excitation experiments

    International Nuclear Information System (INIS)

    Kumar, Rajiv; Sharma, Shagun; Singh, Pradeep; Kharab, Rajesh

    2016-01-01

    The energy-independent touching spheres schemes commonly used for the determination of the safe minimum value of the impact parameter for Coulomb excitation experiments are modified through the inclusion of an energy-dependent term. The touching spheres+3fm scheme after modification emerges out to be the best one while touching spheres+4fm scheme is found to be better in its unmodified form. (orig.)

  8. Intermediate-energy nuclear theory. Final report, July 1, 1976-August 31, 1984

    International Nuclear Information System (INIS)

    Bryan, R.A.

    1985-02-01

    We summarize the research accomplishments of the Texas A and M Medium-Energy Theory Group which was funded by the Department of Energy from July 1976 through August 1984. Our research was mainly in the area of nucleon-nucleon and NNπ theory and data analysis, although some effort was also devoted to the elementary-particle aspects of these hadrons in order to better understand the NN force. Publications and reports are listed

  9. Total electron scattering cross section of Fluorocarbons at intermediate electron energies

    Science.gov (United States)

    Palihawadana, Prasanga; Villela, Gilberto; Ariyasinghe, Wickramasinghe

    2008-10-01

    Total electron scattering cross sections (TCS) of Tetrafluoromethane (CF4), Trifluoromethane (CHF3), Hexafluoroethane (C2F6) and Octafluorocyclobutane (C4F8) have been measured using the linear transmission technique for impact energies 0.10 -- 4.00 keV. These TCS are compared to existing experimental and theoretical TCS in the literature. Based on the present measurements, an empirical formula is developed to predict the TCS of fluorocarbons as a function of incident electron energy.

  10. High-energy X-ray diffraction studies of short- and intermediate-range structure in oxide glasses

    International Nuclear Information System (INIS)

    Suzuya, Kentaro

    2002-01-01

    The feature of high-energy X-ray diffraction method is explained. The oxide glasses studies by using BL04B2, high-energy X-ray diffraction beam line of SPring-8, and the random system materials by high-energy monochromatic X-ray diffraction are introduced. An advantage of third generation synchrotron radiation is summarized. On SPring-8, the high-energy X-ray diffraction experiments of random system are carried out by BL04B2 and BL14B1 beam line. BL04B2 can select Si (111)(E=37.8 keV, λ=0.033 nm) and Si(220)(E=61.7 keV, λ=0.020 nm) as Si monochromator. The intermediate-range structure of (MgO) x (P 2 O 5 ) 1-x glass ,MgP 2 O 6 glass, B 2 O 3 glass, SiO 2 and GeO 2 are explained in detail. The future and application of high-energy X-ray diffraction are stated. (S.Y.)

  11. Total and elastic electron scattering cross sections from Xe at intermediate and high energies

    International Nuclear Information System (INIS)

    Garcia, G; Pablos, J L de; Blanco, F; Williart, A

    2002-01-01

    Experimental total electron scattering cross sections from Xe in the energy range 300-5000 eV have been obtained with experimental errors of about 3%. The method was based on the measurement of the attenuation of a linear electron beam through a Xe gas cell in combination with an electron spectroscopy technique to analyse the energy of the transmitted electrons. Differential and integral elastic cross sections have been calculated using a scattering potential method which includes relativistic effects. The consistency of our theoretical and experimental results is also discussed in the paper. Finally, analytical formulae depending on two parameters, namely the number of target electrons and the atomic polarizability, are given to reproduce the experimental data for Ne, Ar, Kr and Xe in the energy range 500-10 000 eV

  12. Intermediate energy electron impact excitation of composite vibrational modes in phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Lopes, M. C. A.; Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Minas Gerais (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física ‘Gleb Wataghin,’ Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, C.P. 19044, 81531-990 Curitiba, Paraná (Brazil); Silva, G. B. da [Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-05-21

    We report differential cross section results from an experimental investigation into the electron impact excitation of a number of the low-lying composite (unresolved) vibrational modes in phenol (C{sub 6}H{sub 5}OH). The measurements were carried out at incident electron energies in the range 15–40 eV and for scattered-electron angles in the range 10–90°. The energy resolution of those measurements was typically ∼80 meV. Calculations, using the GAMESS code, were also undertaken with a B3LYP/aug-cc-pVDZ level model chemistry, in order to enable us to assign vibrational modes to the features observed in our energy loss spectra. To the best of our knowledge, the present cross sections are the first to be reported for vibrational excitation of the C{sub 6}H{sub 5}OH molecule by electron impact.

  13. Nuclear structure at intermediate energies. Progress report, April 1, 1980-March 31, 1981

    International Nuclear Information System (INIS)

    Phillips, G.C.; Mutchler, G.S.

    1981-01-01

    During the contract year several results of prior LAMPF experiments were completed and prepared for publication. Progress was made in the data analysis of other experiments. Three LAMPF variable energy experiments were carried out with the polarized target PPT-VI: sigma/sub total, transverse/ (p(polarized)p(polarized)) and A/sub YY/ for p(polarized)p(polarized) elastic scattering at 14 energies between 300 and 800 MeV, and A/sub YY/ for p(polarized)p(polarized) → dπ + at a few energies. Proposals were made for future experiments: two for continued nucleon-nucleon studies and one for a search for neutrino oscillations

  14. Analysis for mass distribution of proton-induced reactions in intermediate energy range

    CERN Document Server

    Xiao Yu Heng

    2002-01-01

    The mass and charge distribution of residual products produced in the spallation reactions needs to be studied, because it can provide useful information for the disposal of nuclear waste and residual radioactivity generated by the spallation neutron target system. In present work, the Many State Dynamical Model (MSDM) is based on the Cascade-Exciton Model (CEM). The authors use it to investigate the mass distribution of Nb, Au and Pb proton-induced reactions in energy range from 100 MeV to 3 GeV. The agreement between the MSDM simulations and the measured data is good in this energy range, and deviations mainly show up in the mass range of 90 - 150 for the high energy proton incident upon Au and Pb

  15. Spontaneous fission of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.C.

    1989-04-01

    Although spontaneous fission was discovered in /sup 238/U in 1940, detailed studies of the process were first made possible in the 1960's with the availability of milligram quantities of /sup 252/Cf. The advent of solid-state detectors made it possible to perform measurements of coincident fission fragments from even very short-lived spontaneous fission activities or those available in only very small quantities. Until 1971 it was believed that the main features of the mass and kinetic-energy distributions were essentially the same as those for thermal neutron-induced fission and that all low-energy fission proceeded via asymmetric mass division with total kinetic energies which could be derived by linear extrapolation from those of lighter elements. In 1971, measurements of /sup 257/Fm showed an increase in symmetric mass division with anomalously high TKE's. Subsequent experiments showed that in /sup 258/Fm and /sup 259/Fm, the most probable mass split was symmetric with very high total kinetic energy. Measurements for the heavier elements have shown symmetric mass distributions with both high and low total kinetic energies. Recent results for spontaneous fission properties of the heaviest elements are reviewed and compared with theory. 31 refs., 8 figs., 1 tab.

  16. Energetic proton emission in heavy ion collisions at intermediate energy. Pre-equilibrium and cooperative effects

    International Nuclear Information System (INIS)

    Sapienza, P.; Coniglione, R.; Colonna, M.; Agodi, C.; Alba, R.; Zoppo, A. Del; Finocchiaro, P.; Migneco, E.; Bellia, G.; Greco, V.; Catania Univ.

    2002-01-01

    Energetic proton emission has been investigated as a function of the centrality in the reaction 58 Ni + 58 Ni at 30 AMeV. Protons with energy extending up to a relevant fraction of the total available energy in the reaction were measured and studied. The dependence on the reaction centrality has been extensively investigated and data have been compared with the results of microscopic transport calculations. The more striking observation concerns the extremely energetic proton (E p NN ≥ 130 MeV) multiplicity which is found to increase almost quadratically with the number of participant nucleons thus indicating the onset of a mechanism beyond one and two-body dynamics. (author)

  17. Towards a better understanding of hard photon emission in intermediate energy heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Alba, R.; Maiolino, C.; Agodi, C.; Del Zoppo, A.; Coniglione, R.; Milazzo, P.M.; Sapienza, P.; Bellia, G.; Bruno, M.; Colonna, M.; Colonna, N.; D' Agostino, M.; Fiandri, M.L.; Finocchiaro, P.; Gramegna, F.; Iori, I.; Loukachine, K.; Margagliotti, G.V.; Mastinu, P.F.; Migneco, E.; Moroni, A.; Piattelli, P.; Rui, R.; Santonocito, D.; Tonetto, F.; Vannini, G

    1999-07-26

    High energy photon spectra have been measured in several {sup 58}Ni induced reactions at 30A MeV incident energy. A two source analysis of the data has been performed using a two exponential parameterization of the associated gamma spectra. The relative intensity of the two components has been deduced as a function of the total mass of the interacting system and of the impact parameter. To attempt a characterization of the emission sources, correlations between photons and IMF's have been measured for the first time.

  18. Towards a better understanding of hard photon emission in intermediate energy heavy ion collisions

    Science.gov (United States)

    Alba, R.; Maiolino, C.; Agodi, C.; Del Zoppo, A.; Coniglione, R.; Milazzo, P. M.; Sapienza, P.; Bellia, G.; Bruno, M.; Colonna, M.; Colonna, N.; D'Agostino, M.; Fiandri, M. L.; Finocchiaro, P.; Gramegna, F.; Iori, I.; Loukachine, K.; Margagliotti, G. V.; Mastinu, P. F.; Migneco, E.; Moroni, A.; Piattelli, P.; Rui, R.; Santonocito, D.; Tonetto, F.; Vannini, G.

    High energy photon spectra have been measured in several 58Ni induced reactions at 30A MeV incident energy. A two source analysis of the data has been performed using a two exponential parameterization of the associated gamma spectra. The relative intensity of the two components has been deduced as a function of the total mass of the interacting system and of the impact parameter. To attempt a characterization of the emission sources, correlations between photons and IMF's have been measured for the first time.

  19. Towards a better understanding of hard photon emission in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Alba, R.; Maiolino, C.; Agodi, C.; Del Zoppo, A.; Coniglione, R.; Milazzo, P.M.; Sapienza, P.; Bellia, G.; Bruno, M.; Colonna, M.; Colonna, N.; D'Agostino, M.; Fiandri, M.L.; Finocchiaro, P.; Gramegna, F.; Iori, I.; Loukachine, K.; Margagliotti, G.V.; Mastinu, P.F.; Migneco, E.; Moroni, A.; Piattelli, P.; Rui, R.; Santonocito, D.; Tonetto, F.; Vannini, G.

    1999-01-01

    High energy photon spectra have been measured in several 58 Ni induced reactions at 30A MeV incident energy. A two source analysis of the data has been performed using a two exponential parameterization of the associated gamma spectra. The relative intensity of the two components has been deduced as a function of the total mass of the interacting system and of the impact parameter. To attempt a characterization of the emission sources, correlations between photons and IMF's have been measured for the first time

  20. A multiple parallel-plate avalanche counter for fission-fragment detection

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C.Y., E-mail: wu24@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 9455 (United States); Henderson, R.A. [Lawrence Livermore National Laboratory, Livermore, CA 9455 (United States); Haight, R.C.; Lee, H.Y.; Taddeucci, T.N. [Los Alamos National Laboratory, Los Alamos, MN 87545 (United States); Bucher, B.; Chyzh, A. [Lawrence Livermore National Laboratory, Livermore, CA 9455 (United States); Devlin, M.; Fotiades, N. [Los Alamos National Laboratory, Los Alamos, MN 87545 (United States); Kwan, E. [Lawrence Livermore National Laboratory, Livermore, CA 9455 (United States); National Superconducting Cyclotron Laboratory, East Lansing, MI 48824 (United States); O’Donnell, J.M.; Perdue, B.A.; Ullmann, J.L. [Los Alamos National Laboratory, Los Alamos, MN 87545 (United States)

    2015-09-11

    A new low-mass multiple gas-filled parallel-plate avalanche counter for the fission-fragment detection has been developed to mark the fission occurrence in measurements of the prompt fission neutron energy spectrum as a function of incident neutron energy. It was used successfully for the neutron-induced fission of {sup 235}U and {sup 239}Pu with a total mass near 100 mg each and the spontaneous fission of {sup 252}Cf. Both the incident neutron energy and the prompt fission neutron energy are measured by using the time-of-flight method. The design and performance of this avalanche counter are described.

  1. Neutron emission as a clock and thermometer to probe the dynamics of fusion-fission and quasi-fission

    Science.gov (United States)

    Hinde, D. J.

    1993-03-01

    A compilation of currently available data on pre-scission neutron multiplicities shows clearly that the excitation energy in the fission fragments hardly increases with bombarding energy. This can be explained if fission is always a slow process, whilst evaporation becomes more and more rapid. The neutron clock-thermometer is introduced as a tool to deduce the dynamical timescale for fusion-fission, giving (35±15)×10-21 s. Quasi-fission is faster than fusion-fission because the equilibrium deformation is never reached (the mononucleus is thought to be always very deformed) thus fragment temperatures are higher, and the strong variation of vpre with TKE shows that a significant number of neutrons are emitted while the fragments are accelerating after scission. This appears not to be the case for fusion-fission. The fall in vpre for asymmetric mass-splits suggests that the dynamical time scale is shorter: this will influence fission mass-distributions.

  2. Elastic scattering of polarized protons from 3He at intermediate energies

    International Nuclear Information System (INIS)

    Hasell, D.K.; Bracco, A.; Gubler, H.P.

    1982-09-01

    Using the polarized proton beam facility of the TRIUMF cyclotron, differential cross sections and analyzing powers have been measured in the angular range 20 0 - 150 0 c.m. for proton elastic scattering from 3 He at incident proton energies of 200, 300, 415 and 515 MeV. The differential cross sections exhibit a minimum at t = -0.33 (GeV/c) 2 which becomes more pronounced with increasing energy. There is evidence for the onset of a second minimum corresponding to the interference between double and triple scattering amplitudes. Large analyzing powers are observed at the lower energies. The data from the present analysis, together with data obtained from the literature in the energy range 100-1000 MeV, have been analyzed within the framework of the Glauber multiple scattering formalism. Nucleon-nucleon scattering parameters were taken from a global phase shift analysis of nucleon-nucleon elastic scattering data. Reasonable agreement with the data is obtained

  3. Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Ellis-Gibbings, L.; García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wolverhampton WV1 1LY (United Kingdom); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-09-07

    We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.

  4. A hybrid model for the investigation of heavy ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    Heide, B.M.

    1995-09-01

    The following topics were dealt with: The coupling of the Botzmann-Uehling-Uhlenbeck (BUU) model with Kopenhagen multifragmentation model realising a new hybrid model, application on 197 Au+ 197 Au reactions between 100 and 250 A.MeV, calculation of the chracteristics of the fragmentation system including mass number, excitation energy, angular momenta, two-particle correlation function

  5. Identification of intermediate energy heavy ions in the focal plane of a spectrometer

    International Nuclear Information System (INIS)

    Buenerd, M.; Ballon, J.; Chauvin, J.; Lebrun, D.; Martin, P.; Bonin, B.; Bruge, G.; Lugol, J.C.; Alamanos, N.; Papineau, L.; Roussel, P.

    1985-01-01

    Heavy ions with mass A<14 and E/Aproportional120 MeV have been identified in the focal plane of a magnetic spectrometry by means of a simple telescope made of two slabs of plastic scintillator. The method should be applicable up to Aproportional20 in mass and down to E/Aproportional50 MeV in energy per nucleon. (orig.)

  6. Elastic and inelastic scattering of 12C ions at intermediate energies

    International Nuclear Information System (INIS)

    Hostachy, J.Y.; Buenerd, M.; Chauvin, J.; Lebrun, D.; Martin, P.

    1988-01-01

    Elastic and inelastic scattering of 12 C ions on 12 C and 208 Pb targets have been measured at the incident energies per nucleon E/A=120 MeV/u and E/A=200 MeV/u. Optical-model analysis is reported and nuclear surface transparency effects are discussed, together with the nuclear potential-energy dependence. The transparency region extends down to a radial internuclear distance of about 3 fm for the 12 C- 12 C system and 8 fm for the 12 C- 208 Pb system. A decrease of the imaginary potential with increasing incident energy is deduced for the two systems. Anomalous collapse of the real potential in the surface region is observed for 12 C- 208 Pb system at 200 MeV/u. DWBA analysis of data on the 2 + , 4.4 MeV state of 12 C is reported and trends for the energy dependence of mean-field excitations are deduced. (orig.)

  7. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.; Richter, D.; Seeliger, D.

    1986-01-01

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  8. Verification of MENDL2 and IEAF-2001 Data bases at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Titarenko, Y. E. (Yury E.); Batyaev, V. F. (Vyacheslav F.); Karpikhin, E. I. (Evgeny I.); Zhivun, V. M. (Valery M.); Koldobsky, A. B. (Aleksander B.); Mulambetov, R. D. (Ruslan D.); Mulambetova, S. V.; Trebukhovsky, Y. V. (Yury V.); Zaitsev, S. L.; Lipatov, K. A.; Mashnik, S. G. (Stepan G.); Prael, R. E. (Richard E.)

    2004-01-01

    The work presents results on computer simulations of two experiments whose aim was measuring the threshold activation reaction rates in {sup 12}C, {sup 19}F, {sup 27}Al, {sup 59}Co, {sup 63}Cu, {sup 65}Cu, {sup 64}Zn, {sup 93}Nb, {sup 115}In, {sup 169}Tm, {sup 181}Ta, {sup 197}Au, and {sup 209}Bi thin samples placed inside and outside a 0.8-GeV proton-irradiated 4-cm thick W target and a 92-cm thick W-Na composite target of 15-cm diameter both. In total, more than 1000 values of activation reaction rates were determined in both experiments. The measured data were compared with results by the LAHET code using several nuclear data bases for the respective excitation functions, namely, ENDF/B6 for cross section of neutrons at energies below 20 MeV and MENDL2 together with MENDL2P for cross sections of protons and neutrons of 20 to 100 MeV energies. The recently developed IEAF-2001 data base that provides neutron cross sections up to 150 MeV was used as well. Simulation-to-experiment results obtained using MENDL2 and IEAF-2001 are presented. The agreement between simulation and experiment was found satisfactory for both data bases. Nevertheless; further studies should be conducted to improve simulations of the production of secondary protons and high-energy neutrons, as well as the high-energy neutron elastic scattering. Our results allow drawing some conclusions concerning the reliability of the transport codes and data bases used to simulate Accelerator Driven Systems (ADS), particularly with Na-cooled W targets. The high-energy threshold excitation functions to be used in activation-based unfolding of neutron spectra inside the ADS can be also inferred from our results.

  9. Nuclear fission: a review of experimental advances and phenomenology

    Science.gov (United States)

    Andreyev, A. N.; Nishio, K.; Schmidt, K.-H.

    2018-01-01

    In the last two decades, through technological, experimental and theoretical advances, the situation in experimental fission studies has changed dramatically. With the use of advanced production and detection techniques both much more detailed and precise information can now be obtained for the traditional regions of fission research and, crucially, new regions of nuclei have become routinely accessible for fission studies. This work first of all reviews the recent developments in experimental fission techniques, in particular the resurgence of transfer-induced fission reactions with light and heavy ions, the emerging use of inverse-kinematic approaches, both at Coulomb and relativistic energies, and of fission studies with radioactive beams. The emphasis on the fission-fragment mass and charge distributions will be made in this work, though some of the other fission observables, such as prompt neutron and γ-ray emission will also be reviewed. A particular attention will be given to the low-energy fission in the so far scarcely explored nuclei in the very neutron-deficient lead region. They recently became the focus for several complementary experimental studies, such as β-delayed fission with radioactive beams at ISOLDE(CERN), Coulex-induced fission of relativistic secondary beams at FRS(GSI), and several prompt fusion–fission studies. The synergy of these approaches allows a unique insight in the new region of asymmetric fission around {\\hspace{0pt}}180 Hg, recently discovered at ISOLDE. Recent extensive theoretical efforts in this region will also be outlined. The unprecedented high-quality data for fission fragments, completely identified in Z and A, by means of reactions in inverse kinematics at FRS(GSI) and VAMOS(GANIL) will be also reviewed. These experiments explored an extended range of mercury-to-californium elements, spanning from the neutron-deficient to neutron-rich nuclides, and covering both asymmetric, symmetric and transitional fission regions

  10. Experimental measurement of radiological penumbra associated with intermediate energy x-rays (1 MV) and small radiosurgery field sizes

    International Nuclear Information System (INIS)

    Keller, Brian M.; Beachey, David J.; Pignol, Jean-Philippe

    2007-01-01

    Stereotactic radiosurgery is used to treat intracranial lesions with a high degree of accuracy. At the present time, x-ray energies at or above Co-60 gamma rays are used. Previous Monte Carlo simulations have demonstrated that intermediate energy x-ray photons or IEPs (defined to be photons in the energy range of 0.2-1.2 MeV), combined with small field sizes, produce a reduced radiological penumbra leading to a sharper dose gradient, improved dose homogeneity and sparing of critical anatomy adjacent to the target volume. This hypothesis is based on the fact that, for small x-ray fields, a dose outside the treatment volume is dictated mainly by the range of electrons set into motion by x-ray photons. The purpose of this work is: (1) to produce intermediate energy x rays using a detuned medical linear accelerator (2) to characterize the energy of this beam (3) to measure the radiological penumbra for IEPs and small fields to compare with that produced by 6 MV x rays or Co-60, and (4) to compare these experimental measurements with Monte Carlo computer simulations. The maximum photon energy of our IEP x-ray spectrum was measured to be 1.2 MeV. Gafchromic EBT films (ISP Technologies, Wayne, NJ) were irradiated and read using a novel digital microscopy imaging system with high spatial resolution. Under identical irradiation conditions the measured radiological penumbra widths (80%-20% distance), for field sizes ranging from 0.3x0.3 to 4.0x4.0 cm 2 , varied from 0.3-0.77 mm (1.2 MV) and from 1.1-2.1 mm (6 MV). Even more dramatic were the differences found when comparing the 90%-10% or the 95%-5% widths, which are in fact more significant in radiotherapy. Monte Carlo simulations agreed well with the experimental findings. The reduction in radiological penumbra could be substantial for specific clinical situations such as in the treatment of an ocular melanoma abutting the macula or for the treatment of functional disorders such as trigeminal neuralgia (a nonlethal

  11. Fission dynamics in the proton induced fission of heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rubchenya, V.A. E-mail: rubchen@phys.jyu.fi; Trzaska, W.H.; Itkis, I.M.; Itkis, M.G.; Kliman, J.; Kniajeva, G.N.; Kondratiev, N.A.; Kozulin, E.M.; Krupa, L.; Pokrovski, I.V.; Voskressenski, V.M.; Hanappe, F.; Materna, T.; Dorvaux, O.; Stuttge, L.; Chubarian, G.; Khlebnikov, S.V.; Vakhtin, D.N.; Lyapin, V.G

    2004-04-05

    Multi-parameter correlation study of the reaction {sup 242}Pu(p, f) at E{sub p} 13, 20 and 55 MeV has been carried out. Fission fragment mass and kinetic energy distributions and the double differential neutron spectra have been measured. It was observed that the two-humped shape of mass distributions prevailed up to highest proton energy. Manifestation of the nuclear shell Z 28 near fragment mass A{sub fr} = 70 has been detected. The experimental results were analyzed in the framework of a time-dependent statistical model with inclusion of nuclear friction effects in the fission process. The multi-parameter correlation study of the reaction.

  12. Myocardial perfusion assessment by dual-energy computed tomography in patients with intermediate to high likelihood of coronary artery disease

    International Nuclear Information System (INIS)

    De Zam, M.C.; Capunay, C.; Rodriguez Granillo, G.A.; Deviggiano, A.; Campisi, R.; Munain, M. López de; Vallejos, J.; Carrascosa, P.M.

    2015-01-01

    Objectives. We sought to explore the feasibility and diagnostic performance of dual-energy computed tomography (DECT) for the evaluation of myocardial perfusion in patients with intermediate to high likelihood of coronary artery disease (CAD), and to assess the impact of beam hardening artifacts (HAE). Methods. The present prospective study involved patients with known or suspected CAD referred for myocardial perfusion imaging by single-photon emission computed tomography (SPECT). Twenty patients were included in the study protocol, and scanned using DECT imaging (n = 20). The same pharmacological stress was used for DECT and SPECT scans. Results. A total of 680 left ventricular segments were evaluated by DECT and SPECT. The contrast to noise ratio was 8.8±2.9. The diagnostic performance of DECT was very good in identifying perfusion defects [area under ROC curve (AUC) of DECT 0.90 (0.86-0.94)] compared with SPECT, and remained unaffected when including only segments affected by beam hardening artifacts (BHA) [AUC= DECT 0.90 (0.84-0.96)]. Conclusions. In this pilot investigation, myocardial perfusion assessment by DECT imaging in patients with intermediate to high likelihood of CAD was feasible and remained unaffected by the presence of BHA. (authors) [es

  13. Fission cross section measurements for minor actinides

    Energy Technology Data Exchange (ETDEWEB)

    Fursov, B. [IPPE, Obninsk (Russian Federation)

    1997-03-01

    The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)

  14. Impact of thermal and intermediate energy neutrons on the semiconductor memories for the CERN accelerators

    CERN Document Server

    Cecchetto, Matteo; Gerardin, Simone

    A wide quantity of SRAM memories are employed along the Large Hadron Collider (LHC), the main CERN accelerator, and they are subjected to high levels of ionizing radiations which compromise the reliability of these devices. The Single Event Effect (SEE) qualification for components to be used in the complex high-energy accelerator at CERN relies on the characterization of two cross sections: 200-MeV protons and thermal neutrons. However, due to cost and time constraints, it is not always possible to characterize the SEE response of components to thermal neutrons, which is often regarded as negligible for components without borophosphosilicate glass (BPSG). Nevertheless, as recent studies show, the sensitivity of deep sub-micron technologies to thermal neutrons has increased owing to the presence of Boron 10 as a dopant and contact contaminant. The very large thermal neutron fluxes relative to high-energy hadron fluxes in some of the heavily shielded accelerator areas imply that even comparatively small therm...

  15. Power Output Stability Research for Harvesting Automobile Exhaust Energy with Heat Capacity Material as Intermediate Medium

    Science.gov (United States)

    Xiao, Longjie; He, Tianming; Mei, Binyu; Wang, Yiping; Wang, Zongsong; Tan, Gangfeng

    2018-01-01

    Automobile exhaust energy thermoelectric utilization can promote energy-saving and emission-reduction. Unexpected urban traffic conditions lead to the hot-end temperature instability of the exhaust pipe-mounted thermoelectric generator (TEG), and influence the TEG power generation efficiency. The heat conduction oil circulation located at the hot-end could smooth the temperature fluctuation, at the expense of larger system size and additional energy supply. This research improves the TEG hot-end temperature stability by installing solid heat capacity material (SHCM) to the area between the outer wall of the exhaust pipe and the TEG, which has the merits of simple structure, light weight and no additional energy consumption. The exhaust temperature and flow rate characteristics with various driving conditions are firstly studied for the target engine. Then the convective heat transfer models of SHCM's hot-end and thermoelectric material's cold-end are established. Meanwhile, SHCM thermal properties' effects on the amplitude and response speed of the TEG hot-end temperature are studied. The candidate SHCM with the characteristics of low thermal resistance and high heat capacity is determined. And the heat transfer model going through from TEG's hot-end to the cold-end is established. The results show that the SHCM significantly improves the TEG hot-end temperature stability but slightly reduces the average power output. When the engine working conditions change a lot, the SHCM's improvement on the TEG hot-end temperature stability is more significant, but the reduction of the average power output becomes more remarkable.

  16. Pre-equilibrium particle emission in the heavy ion collisions at intermediate energy

    International Nuclear Information System (INIS)

    Bellia, G.; Migneco, E.; Agodi, C.; Alba, R.; Coniglione, R.; Zoppo, A. del; Finocchiaro, P.; Loukachine, K.; Maiolino, C.; Piattelli, P.; Santonocito, D.; Sapienza, P.; Peghaire, A.

    1996-01-01

    Hard photons and high energy protons from Ar and Xe induced reactions at 44 MeV/u were analysed in a series of experiments performed with the detector MEDEA. A careful analysis shows a strong correlation between hard γ and fast protons giving an unambiguous signature of the n-p first chance Bremsstrahlung hypothesis. Some preliminary results on the emission of fast protons are reported

  17. Hard Photons:. a Probe of Dynamical Effects in Heavy Ion Collisions at Intermediate Energy

    Science.gov (United States)

    Alba, R.; Agodi, C.; Maiolino, C.; Del Zoppo, A.; Colonna, M.; Bellia, G.; Coniglione, R.; Finocchiaro, P.; Loukachine, K.; Migneco, E.; Piattelli, P.; Santonocito, D.; Sapienza, P.; Bruno, M.; D'Agostino, M.; Fiandri, M. L.; Vannini, G.; Colonna, N.; Gramegna, F.; Mastinu, P. F.; Iori, I.; Moroni, A.; Margagliotti, G. V.; Milazzo, P. M.; Rui, R.

    2002-01-01

    Thermal photons have been used as a clock to determine the time of IMF emission during the evolution of the nuclear reaction. The method has been applied to the reaction 58Ni + 197Au at 30 and 45 MeV/amu incident energy. The results put in evidence that the relative contribution of the two possible production mechanisms (dynamical and statistical) is quite different in the two cases. A comparison with theoretical calculations strongly supports the experimental findings.

  18. Hard photon and energetic proton emission in heavy ion collisions at intermediate energy

    Science.gov (United States)

    Sapienza, P.; Coniglione, R.; Migneco, E.; Agodi, C.; Alba, R.; Bellia, G.; Del Zoppo, A.; Finocchiaro, P.; Loukachine, K.; Maiolino, C.; Piattelli, P.; Santonocito, D.; Blumenfeld, Y.; Le Faou, J. H.; Suomijarvi, T.; Frascaria, N.; Roynette, J. C.; Scarpaci, J. A.; Garron, J. P.; Gillibert, A.; Alamanos, N.; Auger, F.; Peghaire, A.; Chomaz, Ph.

    1998-02-01

    The emission of hard photons and pre-equilibrium protons has been investigated in exclusive clusive experiments performed with MEDEA detector. The observation of the γ-proton anticorrelation indicate that the dominant production mechanism is the first chance neutron-proton collisions. Very energetic protons, with energy more than twice the kinematical limit for nucleon-nucleon collisions, have been observed in several reactions.

  19. Experimental apparatus for the study of small angle neutron-proton elastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    Vorobyov, A.A.; Korolev, G.A.; Dobrovolsky, A.V.; Khanzadeev, A.V.; Petrov, G.E.; Spiridenkov, E.M.; Terrien, Y.; Lugol, J.C.; Saudinos, J.; Silverman, B.H.; Wellers, F.

    1988-01-01

    An experimental setup for measurements of absolute differential cross sections and analyzing powers in small angle elastic np scattering is described. The main part of the apparatus consists of a multielectrode ionization chamber IKAR filled with methane, serving as both a gas target and a recoil detector. The apparatus was used in measurements with a polarized neutron beam from the Saturne synchrotron (Saclay, France) in the energy range from 378 to 1135 MeV. (orig.)

  20. H2@Scale: Technical and Economic Potential of Hydrogen as an Energy Intermediate

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jadun, Paige [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pivovar, Bryan S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-09

    The H2@Scale concept is focused on developing hydrogen as an energy carrier and using hydrogen's properties to improve the national energy system. Specifically hydrogen has the abilities to (1) supply a clean energy source for industry and transportation and (2) increase the profitability of variable renewable electricity generators such as wind turbines and solar photovoltaic (PV) farms by providing value for otherwise potentially-curtailed electricity. Thus the concept also has the potential to reduce oil dependency by providing a low-carbon fuel for fuel cell electric vehicles (FCEVs), reduce emissions of carbon dioxide and pollutants such as NOx, and support domestic energy production, manufacturing, and U.S. economic competitiveness. The analysis reported here focuses on the potential market size and value proposition for the H2@Scale concept. It involves three analysis phases: 1. Initial phase estimating the technical potential for hydrogen markets and the resources required to meet them; 2. National-scale analysis of the economic potential for hydrogen and the interactions between willingness to pay by hydrogen users and the cost to produce hydrogen from various sources; and 3. In-depth analysis of spatial and economic issues impacting hydrogen production and utilization and the markets. Preliminary analysis of the technical potential indicates that the technical potential for hydrogen use is approximately 60 million metric tons (MMT) annually for light duty FCEVs, heavy duty vehicles, ammonia production, oil refining, biofuel hydrotreating, metals refining, and injection into the natural gas system. The technical potential of utility-scale PV and wind generation independently are much greater than that necessary to produce 60 MMT / year hydrogen. Uranium, natural gas, and coal reserves are each sufficient to produce 60 MMT / year hydrogen in addition to their current uses for decades to centuries. National estimates of the economic potential of

  1. The VERDI fission fragment spectrometer

    International Nuclear Information System (INIS)

    Fregeau, M. O.; Brys, T.; Gamboni, T.; Geerts, W.; Oberstedt, S.; Oberstedt, A.; Borcea, R.

    2013-01-01

    The VERDI time-of-flight spectrometer is dedicated to measurements of fission product yields and of prompt neutron emission data. Pre-neutron fission-fragment masses will be determined by the double time-of-flight (TOF) technique. For this purpose an excellent time resolution is required. The time of flight of the fragments will be measured by electrostatic mirrors located near the target and the time signal coming from silicon detectors located at 50 cm on both sides of the target. This configuration, where the stop detector will provide us simultaneously with the kinetic energy of the fragment and timing information, significantly limits energy straggling in comparison to legacy experimental setup where a thin foil was usually used as a stop detector. In order to improve timing resolution, neutron transmutation doped silicon will be used. The high resistivity homogeneity of this material should significantly improve resolution in comparison to standard silicon detectors. Post-neutron fission fragment masses are obtained form the time-of-flight and the energy signal in the silicon detector. As an intermediary step a diamond detector will also be used as start detector located very close to the target. Previous tests have shown that poly-crystalline chemical vapour deposition (pCVD) diamonds provides a coincidence time resolution of 150 ps not allowing complete separation between very low-energy fission fragments, alpha particles and noise. New results from using artificial single-crystal diamonds (sCVD) show similar time resolution as from pCVD diamonds but also sufficiently good energy resolution. (authors)

  2. A fission fragment detector for correlated fission output studies

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, S., E-mail: smosby@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tovesson, F.; Couture, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Duke, D.L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States); Kleinrath, V. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Idaho State University, Pocatello, ID 83201 (United States); Meharchand, R.; Meierbachtol, K.; O' Donnell, J.M.; Perdue, B.; Richman, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Shields, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States)

    2014-09-01

    A digital data acquisition system has been combined with a double Frisch gridded ionization chamber for use at both moderated and unmoderated neutron sources at the Los Alamos Neutron Science (LANSCE) facility. The high efficiency of the instrument combined with intense LANSCE beams and new acquisition system permits fission output measurements across 11 orders of magnitude incident neutron energy. The acquisition and analysis system is presented along with the first in-beam performance tests of the setup.

  3. Theoretical research in intermediate-energy nuclear physics. [Technical progress report, April 1, 1993--March 31, 1994

    International Nuclear Information System (INIS)

    Seki, R.

    1994-01-01

    This paper discusses progress that has been made on the following seven problems: (1) (e, e'p) at high momentum transfer; (2) post,acceleration effects in two-nucleon interferometry of heavy-ion collisions; (3) pion-nucleus interactions above 0.5 GeV; (4) chiral symmetry breaking in nuclei and picnic atom anomaly; (5) atomic screening on nuclear astronomical reactions; (6) QCD related work (coherent pion production from skyrmion-antiskyrmion annihilation, QCD in 1 + 1 dimensions, and correlation functions in the QCD vacuum), and (7) kaonic hydrogen atom experiment. The problems deal with various topics mostly in intermediate-energy nuclear physics. We place priority on (1) and (2), and describe them somewhat in detail below. Other problems are our on-going projects, but we are placing lower priority on them in the second and third year

  4. Experimental determination of the effective nucleon-nucleon interaction for p-nucleus reactions at intermediate energies

    International Nuclear Information System (INIS)

    McClelland, J.B.; Aas, B.; Azizi, A.

    1982-01-01

    A complete measurement of the polarization transfer observables has been made for the first time in the (p,p') reaction at intermediate energies. Measurements are reported for the 12 C(p,p') 12 C reaction to the 1 + , T = 0(12.71 MeV) and 1 + , T = 1(15.11 MeV) states at 500 MeV at laboratory scattering angles of 3.5 0 , 5.5 0 , 7.5 0 , and 12.0 0 . Linear combinations of these observables are shown to exhibit a very selective dependence on the isoscalar and isovector spin-dependent components of the nucleon-nucleon interaction. To the extent of the validity of the single collision approximation, these amplitudes are compared directly to the free nucleon-nucleon amplitudes at small momentum transfers

  5. The decay of hot nuclei formed in La-induced reactions at intermediate energies

    International Nuclear Information System (INIS)

    Libby, B.; Mignerey, A.C.; Madani, H.; Marchetti, A.A.; Colonna, M.; DiToro, M.

    1992-01-01

    The decay of hot nuclei formed in lanthanum-induced reactions utilizing inverse kinematics has been studied from E/A = 35 to 55 MeV. At each bombarding energy studied, the probability for the multiple emission of complex fragments has been found to be independent of target. Global features (total charge, source velocity) of the reaction La + Al at E/A = 45 MeV have been reproduced by coupling a dynamical model to study the collision stage of the reaction to a statistical model of nuclear decay

  6. High energy x-radiographic assessment of conditioned intermediate level waste blocks

    International Nuclear Information System (INIS)

    Lewcock, A.I.; Burch, S.F.; Reynolds, W.N.; Pullen, D.A.W.; Smith, D.

    1985-07-01

    This report describes an effective technique for examining the quality of the solidification matrix material in a 500 litre waste drum, testing for homogeneity and major cracks and the confirmation of set. A high energy x-ray source, (an 8 MeV Linac) and a special x-ray TV system, were used to examine several different types of solidified waste form, with and without background radiation, simulated by the use of an uncollimated radiographic isotope. The system as tested showed no discernable image degradation when the isotope was positioned to give a representative background dose as experienced with active ILW monoliths. (author)

  7. γ-rays as a probe to study nuclear dynamics and nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Schutz, Y.

    1987-01-01

    The usefulness of gamma rays in nuclear physics is reviewed, and it is shown how they offer insight into the structure and damping of giant resonances, and how they can be used as an isospin filter. Results from inclusive and exclusive experiments at GANIL are discussed. It is stressed that although the production of high energy gamma rays in heavy ion reactions between 30 MeV/A and 86 MeV/A is understood qualitatively, most models fail in being more quantitative

  8. The (3He,t) and (d,2He)reactions at intermediate energies

    International Nuclear Information System (INIS)

    Brockstedt, A.

    1987-09-01

    The ( 3 He,t) reaction has been studied at 0.6-2.3 GeV at small scattering angles, 0-7 degrees, on various nuclei ( 12 C, 13 C, 26 Mg, 40 Ca, 48 Ca, 54 Fe, 90 Zr, 159 Tb, 208 Pb) including a proton target. The reaction is a single-step reaction and selects the spin-isospin channel. Angular distributions for low-lying states in 12 N are well described by DWIA calculations. From 13 C to 13 N transitions the ratio J στ /J τ , at momentum transfer, q, close to zero, is derived. The ratio remains roughly constant in the region 300 - 700 MeV/nucleon. The position of the quasi-free peak is shifted compared with free nucleon-nucleon scattering. The shift is towards higher excitation energies at q approx 1.4 fm -1 , and towards lower excitation energies at q approx 2.5 fm -1 . The p( 3 He,t)Δ ++ reaction is analysed as one-pion exchange and the ( 3 He,t) form factor is extracted. The shape and position of the Δ resonance seem to be independent of target mass for the targets studied. Compared with the p to Δ ++ transition the position is shifted towards lower excitation energy in nuclei. The (d,2p[ 1 S 0 ]) reaction, with the two protons in an 1 S 0 state labelled 2 He, is studied at 0.65 and 2.0 GeV at small angles, 0-4 degrees, on some of the targets used in the ( 3 He,t) experiment (p, 12 C, 40 Ca, 54 Fe). This reaction is also a one-step reaction that can be used for studies of spin-isospin excitations. Cross sections and tensor analysing powers are determined for the p(d, 2 He)n reaction. These results are compared with PWIA calculations. The Δ resonance in carbon is also here shifted down in excitation energy compared with the proton target. (author)

  9. Microscopic theory for nucleon-nucleus optical potential in intermediate energies

    International Nuclear Information System (INIS)

    He Guozhu; Cai Chonghai

    1984-01-01

    Based on the scattering theory of KMT and FGH we calculate the nucleon-nucleus optical potentials of 4 He, 16 O and 40 Ca from the Paris N-N potential given by M. Lacombe et al. The real part Vsub(R)(r) of our optential has the form of Woods-Saxon when the kinetic energy E of the incident nucleon is low. The depth of Vsub(R)(r) will decrease as E increases, and it turns into positive in the interior of nucleus when E approx.= 300 MeV. The repulsive effect in the interior of nucleus increases rapidly as E increases even more, butthere always exists some attractive effect at the surface of nucleus. Therefore, Vsub(R)(r) has generally the wine-bottle bottom shape. We also calculate the quatity Jv/N = (4π/N)∫sub(0)sub(infinity)Vsub(R)(r)r 2 dr. Our results are basically in acordance with those of M.Jaminon et al's relativistic Hatree calculation as well as the experimental results. In this work we also calculate the imaginary part of optical potential and its variation with the kinetic energy of the incident nucleon

  10. Intermediate steps towards the 2000 W society in Switzerland: An energy-economic scenario analysis

    International Nuclear Information System (INIS)

    Schulz, Thorsten F.; Kypreos, Socrates; Barreto, Leonardo; Wokaun, Alexander

    2008-01-01

    In the future, sustainable development under the umbrella of the 2000 W society could be of major interest. Could the target of the 2000 W society, i.e. a primary energy per capita (PEC) consumption of 2000 W, be realized until 2050? Various combinations of PEC and CO 2 targets are tested, and the additional costs to be paid by the society are estimated. The assessment is carried out with the Swiss MARKAL model, a bottom-up energy-system model projecting future technology investments for Switzerland. The analysis reveals that the 2000 W society should be seen as a long-term goal. For all contemplated scenarios, a PEC consumption of 3500 W per capita (w/cap) is feasible in the year 2050. However, strong PEC consumption targets can reduce CO 2 emissions to an equivalent of 5% per decade at maximum. For stronger CO 2 emission reduction goals, corresponding targets must be formulated explicitly. At an oil price of 75 US$ 2000 /bbl in 2050, the additional (cumulative, discounted) costs to reach a 10% CO 2 reduction per decade combined with a 3500 W per capita target amount to about 40 billion US$ 2000 . On the contrary, to reach pure CO 2 reduction targets is drastically cheaper, challenging the vision of the 2000 W society

  11. Delayed fission of atomic nuclei (To the 50th anniversary of the discovery)

    Science.gov (United States)

    Skobelev, N. K.

    2017-09-01

    The history of the discovery of delayed nuclear fission is presented, and the retrospective of investigations into this phenomenon that were performed at various research centers worldwide is outlined. The results obtained by measuring basic delayed-fission features, including the fission probability, the total kinetic energy of fission fragments, and their mass distributions, are analyzed. Recommendations concerning further studies in various regions of nuclear map with the aim of searches for and investigation of atomic nuclei undergoing delayed fission are given. Lines of further research into features of delayed fission with the aim of solving current problems of fission physics are discussed.

  12. 4He(p,2p)3H reaction at intermediate energies

    International Nuclear Information System (INIS)

    van Oers, W.T.H.; Murdoch, B.T.; Koene, B.K.S.; Hasell, D.K.; Abegg, R.; Margaziotis, D.J.; Epstein, M.B.; Moss, G.A.; Greeniaus, L.G.; Greben, J.M.; Cameron, J.M.; Rogers, J.G.; Stetz, A.W.

    1982-01-01

    The 4 He(p,2p) 3 He reaction has been studied at 250, 350, and 500 MeV using coplanar symmetric and asymmetric geometries. The data are presented as energy-sharing spectra, coplanar symmetric angular distributions, and quasifree angular distributions. A comparison with distorted-wave impulse approximation calculations indicates reasonable agreement for small recoil momenta (q< or approx. =150 MeV/c). For larger recoil momenta, the distorted-wave impulse approximation calculations increasingly underestimate the data. The discrepancies are substantially reduced by inclusion of a spin-orbit term in the optical potential used to generate the distorted waves. Improvements of the single particle wave function for the struck nucleon influence the calculations to a lesser degree. The remaining discrepancies at large recoil momenta may, in part be ascribed to multiple scattering effects and exchange processes not included in the standard distorted-wave impulse approximation

  13. Salient features of heavy ion reactions in the intermediate energy region

    International Nuclear Information System (INIS)

    Jakobsson, B.

    1987-01-01

    In this lecture the attention is focused on the most central and therefore generally also the most violent collisions. It is necessary to remember that the non-participating volumes could be very different for symmetric and asymmetric reactions. The onset of the multifragmentation channel or rather the cease of the fusion process is the first topic to be discussed. This question is directly related to the limitation in energy and momentum transfer and thus to the question about nuclear transparency. Exclusive data on multifragmentation on an event-by-event basis, which may help the model constructors, is presented as the second topic. In lecture the onset of fragmentation, fragment sizes in multifragmentation processes, the origin of light particle correlations and emission of pions and kaons close to the threshold are discussed

  14. General Description of Fission Observables - JEFF Report 24. GEF Model

    International Nuclear Information System (INIS)

    Schmidt, Karl-Heinz; Jurado, Beatriz; Amouroux, Charlotte

    2014-06-01

    The Joint Evaluated Fission and Fusion (JEFF) Project is a collaborative effort among the member countries of the OECD Nuclear Energy Agency (NEA) Data Bank to develop a reference nuclear data library. The JEFF library contains sets of evaluated nuclear data, mainly for fission and fusion applications; it contains a number of different data types, including neutron and proton interaction data, radioactive decay data, fission yield data and thermal scattering law data. The General fission (GEF) model is based on novel theoretical concepts and ideas developed to model low energy nuclear fission. The GEF code calculates fission-fragment yields and associated quantities (e.g. prompt neutron and gamma) for a large range of nuclei and excitation energy. This opens up the possibility of a qualitative step forward to improve further the JEFF fission yields sub-library. This report describes the GEF model which explains the complex appearance of fission observables by universal principles of theoretical models and considerations on the basis of fundamental laws of physics and mathematics. The approach reveals a high degree of regularity and provides a considerable insight into the physics of the fission process. Fission observables can be calculated with a precision that comply with the needs for applications in nuclear technology. The relevance of the approach for examining the consistency of experimental results and for evaluating nuclear data is demonstrated. (authors)

  15. The energy spectrum of delayed neutrons from thermal neutron induced fission of 235U and its analytical approximation

    International Nuclear Information System (INIS)

    Doroshenko, A.Yu.; Tarasko, M.Z.; Piksaikin, V.M.

    2002-01-01

    The energy spectrum of the delayed neutrons is the poorest known of all input data required in the calculation of the effective delayed neutron fractions. In addition to delayed neutron spectra based on the aggregate spectrum measurements there are two different approaches for deriving the delayed neutron energy spectra. Both of them are based on the data related to the delayed neutron spectra from individual precursors of delayed neutrons. In present work these two different data sets were compared with the help of an approximation by gamma-function. The choice of this approximation function instead of the Maxwellian or evaporation type of distribution is substantiated. (author)

  16. MENDL2 and IEAF-2001 nuclide production yields data bases verification at intermediate energies.

    Energy Technology Data Exchange (ETDEWEB)

    Titarenko, Y. E. (Yury E.); Batyaev, V. F. (Vyacheslav F.); Zhivun, V. M. (Valery M.); Mulambetov, R. D. (Ruslan D.); Mulambetova, S. V.; Zaitsev, S. L.; Lipatov, K. A.; Mashnik, S. G. (Stepan G.); Prael, R. E. (Richard E.)

    2004-01-01

    The work presents the results of computer simulation of two experiments which aim was measuring the threshold activation reaction rates in {sup 12}C, {sup 19}F, {sup 27}Al, {sup 59}Co, {sup 63}Cu, {sup 65}Cu, {sup 64}Zn, {sup 93}Nb, {sup 115}In, {sup 169}Tm, {sup 181}Ta, {sup 197}Au, and {sup 209}Bi thin samples placed inside and outside the 0.8-GeV proton-irradiated 4-cm thick W target and 92-cm thick W-Na composite target of 15-cm diameter both. In total, more than 1000 values of activation reaction were determined in the both experiments. The measured reaction rates were compared with the rates simulated by the LAHET code with the use of several nuclear databases for the respective excitation functions, namely, MENDL2/2P for neutron/proton cross sections up to 100 MeV, and recently developed IEAF-2001 that provides neutron cross sections up to 150 MeV. The comparison between the simulation-to-experiment agreements obtained via the MENDL2 and IEAF-2001 is presented. The agreement between simulation and experiment has been found generally satisfactory for both of the databases. The high-energy threshold excitation functions to be used in the activation-based unfolding of neutron spectra inside the Accelerator Driven Systems (ADS), particularly with Na-cooled W targets, can be inferred from the results.

  17. Future directions in intermediate energy heavy ion physics. A proposed expansion of the Holifield Facility

    International Nuclear Information System (INIS)

    1986-02-01

    A proposal is presented for a major accelerator addition to the Holifield Heavy Ion Research Facility. The expanded facility will provide ion beams of mass 1 to 238 amu with a combination of energy, intensity, momentum resolution, and beam quality not currently available at any other facility in North America. The physics motivation for such an addition is discussed, and involves physics dominated by meson-exchange forces, Coulomb-force dominated physics, and possibly a regime where the quark and gluon degrees of freedom are significant. The physics research would include topics in atomic and interdisciplinary areas as well as nuclear physics. Some remarks are made on the merits of Oak Ridge as a site for this facility, placing the proposal in some historical perspective. The accelerator system is then described, giving the required beam properties, and the parameters of the synchrotron ring components, injection, ring magnets, RF systems, vacuum system, and electron cooling system and stochastic cooling system requirements. Also described are such facilities as buildings, beam transport and shielding, and experimental facilities, including target areas

  18. Future directions in intermediate energy heavy ion physics. A proposed expansion of the Holifield Facility

    Energy Technology Data Exchange (ETDEWEB)

    1986-02-01

    A proposal is presented for a major accelerator addition to the Holifield Heavy Ion Research Facility. The expanded facility will provide ion beams of mass 1 to 238 amu with a combination of energy, intensity, momentum resolution, and beam quality not currently available at any other facility in North America. The physics motivation for such an addition is discussed, and involves physics dominated by meson-exchange forces, Coulomb-force dominated physics, and possibly a regime where the quark and gluon degrees of freedom are significant. The physics research would include topics in atomic and interdisciplinary areas as well as nuclear physics. Some remarks are made on the merits of Oak Ridge as a site for this facility, placing the proposal in some historical perspective. The accelerator system is then described, giving the required beam properties, and the parameters of the synchrotron ring components, injection, ring magnets, RF systems, vacuum system, and electron cooling system and stochastic cooling system requirements. Also described are such facilities as buildings, beam transport and shielding, and experimental facilities, including target areas. (LEW)

  19. Intermediate energy electron cooling for antiproton sources using a Pelletron accelerator

    International Nuclear Information System (INIS)

    Cline, D.B.; Adney, J.; Ferry, J.; Kells, W.; Larson, D.J.; Mills, F.E.; Sundquist, M.

    1983-01-01

    It has been shown at FNAL that the electron cooling of protons is a very efficient method for reaching high luminosity in a proton beam. The emittance of the 120 KeV electron beam used at Fermilab corresponds to a cathode temperature of 0.1 eV. In order to apply cooling techniques to GeV proton beams the electron energies required are in the MeV range. In the experiment reported in this paper the emittance of a 3-MeV Pelletron electron accelerator was measured to determine that its emittance scaled to a value appropriate for electron cooling. The machine tested was jointly owned and operated by the University of California at Santa Barbara and National Electrostatics Corporation for research into free-electron lasers which also require low emittance beams for operation. This paper describes the thermal emittance of the beam to be the area in phase space in which 90% of the beam trajectories lie and goes on to describe the emittance-measurement method both in theory and application

  20. Study of interactions between hadrons and light nuclei at intermediate energies

    International Nuclear Information System (INIS)

    Levy, Dominique.

    1977-01-01

    A theoretical study of the following reactions: πN→πN, πd→πd and Nd→Nπd, at incident energies of a few hundreds MeV is presented. The amplitudes of the πN→πN reaction are studied when at least one of the external particles is off-mass-shell. This study leads to the selection of a model used subsequently. For the πd→πd reaction, the simple scattering model is analyzed in detail then the Glauber and Brueckner double scattering models are compared. In the simple scattering model, the effect of the Fermi motion is examined in detail: a calculation of this effect, taking into account both the deuteron D wave and the nucleon spins is completed. Several approximations to the Fermi integral are also presented and the deficiencies of the models are discussed. In the inelastic Nd→Nπd reaction, the peak observed around 1150 MeV in the invariant mass spectrum of the Nπ final system is studied. This Nπ(1150) effect is explained using a Deck-type model. Other mechanisms that might contribute to the Nd→Nπd reaction, in particular at high transfers, are analyzed [fr