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471 results on '"Barreau, G."'

1. Study of the 238U(d,p) surrogate reaction via the simultaneous measurement of gamma-decay and fission probabilities

Author

Ducasse, Q., Jurado, B., Aïche, M., Marini, P., Mathieu, L., Görgen, A., Guttormsen, M., Larsen, A. C., Tornyi, T., Wilson, J. N., Barreau, G., Boutoux, G., Czajkowski, S., Giacoppo, F., Gunsing, F., Hagen, T. W., Lebois, M., Lei, J., Méot, V., Morillon, B., Moro, A., Renstrøm, T., Roig, O., Rose, S. J., Sérot, O., Siem, S., Tsekhanovich, I., Tveten, G. M., and Wiedeking, M.

Subjects
Nuclear Experiment
Abstract

We investigated the 238U(d,p) reaction as a surrogate for the n + 238U reaction. For this purpose we measured for the first time the gamma-decay and fission probabilities of 239U* simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuum-discretized coupled-channels and distorted-wave Born approximations were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. In the region where the fission and gamma-decay probabilities compete, the corrected fission probability is in agreement with neutron-induced data, whereas the gamma-decay probability is much higher than the neutron-induced data. The performed statistical-model calculations are not able to explain these results., Comment: Includes modifications due to referee remarks

Published
2015
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2. High-spin structures of 124-131Te: Competition of proton and neutron pair breakings

Author

Astier, A., Porquet, M. -G., Venkova, Ts., Theisen, Ch., Duchene, G., Azaiez, F., Barreau, G., Curien, D., Deloncle, I., Dorvaux, O., Gall, B. J. P., Houry, M., Lucas, R., Redon, N., Rousseau, M., and Stezowski, O.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The 124-131Te nuclei have been produced as fission fragments in two fusion reactions induced by heavy-ions (12C + 238U at 90 MeV bombarding energy and 18O + 208Pb at 85 MeV) and studied with the Euroball array. Their high-spin level schemes have been extended to higher excitation energy from the triple gamma-ray coincidence data. The gamma-gamma angular correlations have been analyzed in order to assign spin and parity values to many observed states. Moreover the half-lives of isomeric states have been measured from the delayed coincidences between the fission-fragment detector SAPhIR and Euroball, as well as from the timing information of the Ge detectors. The behaviors of the yrast structures identified in the present work are first discussed in comparison with the general features known in the mass region, particularly the breakings of neutron pairs occupying the nuh11/2 orbit identified in the neighboring Sn nuclei. The experimental level schemes are then compared to shell-model calculations performed in this work. The analysis of the wave functions shows the effects of the proton-pair breaking along the yrast lines of the heavy Te isotopes., Comment: accepted for publication in Eur. Phys. J. A

Published
2013
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3. Isotopic Yield Distributions of Transfer- and Fusion-Induced Fission from 238U+12C Reactions in Inverse Kinematics

Author

Caamaño, M., Delaune, O., Farget, F., Derkx, X., Schmidt, K. -H., Audouin, L., Bacri, C. -O., Barreau, G., Benlliure, J., Casarejos, E., Chbihi, A., Fernandez-Dominguez, B., Gaudefroy, L., Golabek, C., Jurado, B., Lemasson, A., Navin, A., Rejmund, M., Roger, T., Shrivastava, A., and Schmitt, C.

Subjects
Nuclear Experiment
Abstract

A novel method to access the complete identification in atomic number Z and mass A of fragments produced in low-energy fission of actinides is presented. This method, based on the use of multi- nucleon transfer and fusion reactions in inverse kinematics, is applied in this work to reactions between a 238U beam and a 12C target to produce and induce fission of moderately excited actinides. The fission fragments are detected and fully identified with the VAMOS spectrometer of GANIL, allowing the measurement of fragment yields of several hundreds of isotopes in a range between A ~ 80 and ~ 160, and from Z ~ 30 to ~ 64. For the first time, complete isotopic yield distributions of fragments from well-defined fissioning systems are available. Together with the precise measurement of the fragment emission angles and velocities, this technique gives further insight into the nuclear-fission process., Comment: 22 pages, 21 figures

Published
2013
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4. Isotopic fission fragment distributions as a deep probe to fusion-fission dynamics

Author

Farget, F., Caamano, M., Delaune, O., Tarasov, O. B., Derkx, X., Schmidt, K. -H., Amthor, A. M., Audouin, L., Bacri, C. -O., Barreau, G., Bastin, B., Bazin, D., Blank, B., Benlliure, J., Caceres, L., Casarejos, E., Chibihi, A., Fernandez-Dominguez, B., Gaudefroy, L., Golabek, C., Grevy, S., Jurado, B., Kamalou, O., Lemasson, A., Lukyanov, S., Mittig, W., Morrissey, D. J., Navin, A., Pereira, J., Perrot, L., Rejmund, M., Roger, T., Saint-Laurent, M. -G., Savajols, H., Schmitt, C., Sherill, B. M., Stodel, C., Taieb, J., Thomas, J. -C., and Villari, A. C.

Subjects
Nuclear Experiment
Abstract

During the fission process, the nucleus deforms and elongates up to the two fragments inception and their final separation at scission deformation. The evolution of the nucleus energy with deformation is determined by the macroscopic properties of the nucleus, and is also strongly influenced by the single-particle structure of the nucleus. The fission fragment distribution is a direct consequence of the deformation path the nucleus has encountered, and therefore is the most genuine experimental observation of the potential energy landscape of the deforming nucleus. Very asymmetric fusion-fission reactions at energy close to the Coulomb barrier, produce well-defined conditions of the compound nucleus formation, where processes such as quasi-fission, pre-equilibrium emission and incomplete fusion are negligible. In the same time, the excitation energy is sufficient to reduce significantly structural effects, and mostly the macroscopic part of the potential is responsible for the formation of the fission fragments. We use inverse kinematics combined with spectrometers to select and identify the fission fragments produced in $^{238}$U+$^{12}$C at a bombarding energy close to and well-above the Coulomb barrier. For the first time, the isotopic yields are measured over the complete atomic-number distribution, between Z=30 and Z=63. The experimental set-up also allows to identify transfer-induced reactions, which lead to low-energy fission where the nuclear shell structure shows a strong influence on the fission-fragment distributions. The resulting set of data gives the possibility to observe the fission fragment properties over a wide range of excitation energy, and they reveal the vanishing of the shell effects in the potential energy of the fissioning nucleus, as well as the influence of fission dynamics., Comment: Invited Plenary Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

Published
2012
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5. High-spin structures of five N=82 isotones: 136Xe, 137Cs, 138Ba, 139La, and 140Ce

Author

Astier, A., Porquet, M. -G., Venkova, Ts., Verney, D., Theisen, Ch., Duchene, G., Azaiez, F., Barreau, G., Curien, D., Deloncle, I., Dorvaux, O., Gall, B. J. P., Houry, M., Lucas, R., Redon, N., Rousseau, M., and Stezowski, O.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Five N=82 isotones have been produced in two fusion-fission reactions and their gamma-rays studied with the Euroball array. The high-spin states of 139La have been identified for the first time, while the high-spin yrast and near-to-yrast structures of the four others have been greatly extended. From angular correlation analysis,spin values have been assigned to some states of 136Xe and 137Cs. Several cascades involving gamma-rays of 139La have been found to be delayed, they deexcite an isomeric state with T1/2= 315(35) ns located at 1800-keV excitation energy. The excited states of these five N=82 isotones are expected to be due to various proton excitations involving the three high-j subshells located above the Z=50 shell closure. This is confirmed by the results of shell-model calculations performed in this work. In addition, high-spin states corresponding to the excitation of the neutron core have been unambiguously identified in 136Xe, 137Cs, and 138Ba., Comment: 18 pages, 18 figures, 10 tables, accepted for publication in Phys. Rev. C

Published
2012
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6. High-spin states with seniority v=4,4,6 in 119-126Sn

Author

Astier, A., Porquet, M. -G., Theisen, Ch., Verney, D., Deloncle, I., Houry, M., Lucas, R., Azaiez, F., Barreau, G., Curien, D., Dorvaux, O., Duchene, G., Gall, B. J. P., Redon, N., Rousseau, M., and Stezowski, O.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The 119-126Sn nuclei have been produced as fission fragments in two reactions induced by heavy ions: 12C+238U at 90 MeV bombarding energy, 18O+208Pb at 85 MeV. Their level schemes have been built from gamma rays detected using the Euroball array. High-spin states located above the long-lived isomeric states of the even- and odd-A 120-126Sn nuclei have been identified. Moreover isomeric states lying around 4.5 MeV have been established in 120,122,124,126Sn from the delayed coincidences between the fission fragment detector SAPhIR and the Euroball array. The states located above 3-MeV excitation energy are ascribed to several broken pairs of neutrons occupying the nu h11/2 orbit. The maximum value of angular momentum available in such a high-j shell, i.e. for mid-occupation and the breaking of the three neutron pairs, has been identified. This process is observed for the first time in spherical nuclei., Comment: 20 pages, 22 figures, 12 tables, accepted for publication in Physical Review C

Published
2012
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9. The electron–ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)—A conceptual design study

Author

Antonov, A.N., Gaidarov, M.K., Ivanov, M.V., Kadrev, D.N., Aïche, M., Barreau, G., Czajkowski, S., Jurado, B., Belier, G., Chatillon, A., Granier, T., Taieb, J., Doré, D., Letourneau, A., Ridikas, D., Dupont, E., Berthoumieux, E., Panebianco, S., Farget, F., Schmitt, C., Audouin, L., Khan, E., Tassan-Got, L., Aumann, T., Beller, P., Boretzky, K., Dolinskii, A., Egelhof, P., Emling, H., Franzke, B., Geissel, H., Kelic-Heil, A., Kester, O., Kurz, N., Litvinov, Y., Münzenberg, G., Nolden, F., Schmidt, K.-H., Scheidenberger, Ch., Simon, H., Steck, M., Weick, H., Enders, J., Pietralla, N., Richter, A., Schrieder, G., Zilges, A., Distler, M.O., Merkel, H., Müller, U., Junghans, A.R., Lenske, H., Fujiwara, M., Suda, T., Kato, S., Adachi, T., Hamieh, S., Harakeh, M.N., Kalantar-Nayestanaki, N., Wörtche, H., Berg, G.P.A., Koop, I.A., Logatchov, P.V., Otboev, A.V., Parkhomchuk, V.V., Shatilov, D.N., Shatunov, P.Y., Shatunov, Y.M., Shiyankov, S.V., Shvartz, D.I., Skrinsky, A.N., Chulkov, L.V., Danilin, B.V., Korsheninnikov, A.A., Kuzmin, E.A., Ogloblin, A.A., Volkov, V.A., Grishkin, Y., Lisin, V.P., Mushkarenkov, A.N., Nedorezov, V., Polonski, A.L., Rudnev, N.V., Turinge, A.A., Artukh, A., Avdeichikov, V., Ershov, S.N., Fomichev, A., Golovkov, M., Gorshkov, A.V., Grigorenko, L., Klygin, S., Krupko, S., Meshkov, I.N., Rodin, A., Sereda, Y., Seleznev, I., Sidorchuk, S., Syresin, E., Stepantsov, S., Ter-Akopian, G., Teterev, Y., Vorontsov, A.N., Kamerdzhiev, S.P., Litvinova, E.V., Karataglidis, S., Alvarez Rodriguez, R., Borge, M.J.G., Fernandez Ramirez, C., Garrido, E., Sarriguren, P., Vignote, J.R., Fraile Prieto, L.M., Lopez Herraiz, J., Moya de Guerra, E., Udias-Moinelo, J., Amaro Soriano, J.E., Lallena Rojo, A.M., Caballero, J.A., Johansson, H.T., Jonson, B., Nilsson, T., Nyman, G., Zhukov, M., Golubev, P., Rudolph, D., Hencken, K., Jourdan, J., Krusche, B., Rauscher, T., Kiselev, D., Trautmann, D., Al-Khalili, J., Catford, W., Johnson, R., Stevenson, P.D., Barton, C., Jenkins, D., Lemmon, R., Chartier, M., Cullen, D., Bertulani, C.A., and Heinz, A.

Published
2011
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12. γ-Ray Studies of Induced Fission 12C+238U

Author

Houry, M., Theisen, Ch., Lucas, R., Becker, F., Korten, W., Le Coz, Y., Barreau, G., Doan, T. P., Durell, J., Grimwood, D., Roach, A., Smith, A. G., Varley, B. J., Ethvignot, Th., Deloncle, I., Porquet, M. G., Astier, A., Perries, S., Redon, N., Smit, F. D., editor, Lindsay, R., editor, and Förtsch, S. V., editor

Published
1999
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14. High-spin structures of 51121, 123, 125, 127Sb nuclei: Single proton and core-coupled states

Author

Porquet, M. -G., Venkova, Ts., Lucas, R., Astier, A., Bauchet, A., Deloncle, I., Prévost, A., Azaiez, F., Barreau, G., Bogachev, A., Buforn, N., Buta, A., Curien, D., Doan, T. P., Donadille, L., Dorvaux, O., Duchêne, G., Durell, J., Ethvignot, Th., Gall, B. P. J., Grimwood, D., Houry, M., Khalfallah, F., Korten, W., Lalkovski, S., Le Coz, Y., Meyer, M., Minkova, A., Piqueras, I., Redon, N., Roach, A., Rousseau, M., Schulz, N., Smith, A. G., Stézowski, O., Theisen, Ch., and Varley, B. J.

Published
2005
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15. High-spin study of odd- A 49In isotopes beyond the neutron mid-shell

Author

Lucas, R., Porquet, M.-G., Venkova, Ts., Deloncle, I., Houry, M., Theisen, Ch., Astier, A., Bauchet, A., Lalkovski, S., Barreau, G., Buforn, N., Doan, T.P., Donadille, L., Dorvaux, O., Durell, J., Ethvignot, Th., Gall, B.P.J., Grimwood, D., Korten, W., Le Coz, Y., Meyer, M., Minkova, A., Prévost, A., Redon, N., Roach, A., Schulz, N., Smith, A.G., Stézowski, O., and Varley, B.J.

Published
2002
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21. Development of an experimental set-up for the measurement of neutron-induced fission and capture cross sections of radioactive fissile nuclei

Author

Companis I., Aïche M., Mathieu L., Schillebeeckx P., Heyse J., Barreau G., Czajkowski S., Ducasse Q., Gunsing F., Jurado B., Kessedjian G., Matarranz J., Plompen A.J.M., and Tsekhanovich I.

Subjects
Physics, QC1-999
Abstract

A new experimental set-up for a simultaneous measurement of neutron induced capture and fission cross sections was designed, assembled and optimized. The measurements will be performed at GEel LINear Accelerator (GELINA) neutron time-of-flight facility in Belgium, where neutron cross sections can be measured over a wide energy range with high energy resolution. The fission events detector consists of a dedicated multi-plate high efficiency fission ionization chamber (IC). The γ-rays produced in capture reaction are detected by an efficient array of C6D6 scintillators. Fission γ-rays events are distinguished from capture events by the anticoincidence signals from the IC and the C6D6 detectors. For the undetected fission events a correction has to be applied with respect to the efficiency of the IC that should be high and known with a high precision. Another important issue is the good separation between fission-fragment (FF) and the high alpha pile-up. The performances of the IC during test experiments are presented, focusing in particular on the detection efficiency.

Published
2013
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22. Complete isotopic distributions of fragments produced in transfer- and fusion-induced reactions

Author

Delaune O., Caamaño M., Farget F., Tarasov O.B., Derkx X., Schmidt K.-H., Audouin L., Amthor A.M., Bacri C.-O., Barreau G., Bastin B., Bazin D., Benlliure J., Blank B., Cacères L., Casarejos E., Fernández-Domínguez B., Gaudefroy L., Golabek C., Grévy S., Jurado B., Kamalou O., Lemasson A., Lukyanov S.M., Mittig W., Morrissey D.J., Navin A., Pereira J., Perrot L., Rejmund M., Roger T., Saint-Laurent M.G., Savajols H., Schmitt C., Sherrill B.M., Stodel C., Thomas J.C., and Villari A.C.C.

Subjects
Physics, QC1-999
Abstract

Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with centre of mass energies from 10 to 240 MeV and their decay by fission was investigated with GANIL spectrometers. Fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of the fusion-fission mechanism.

Published
2013
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23. Neutron-induced cross sections of actinides via the surrogate-reaction method

Author

Ducasse Q., Jurado B., Aiche M., Tornyi T., Görgen A., Wilson J.N., Barreau G., Companis I., Czajkowski S., Giacoppo F., Gunsing F., Guttormsen M., Larsen A.C., Lebois M., Matarranz J., Renstrøm T., Rose S., Siem S., Tsekhanovich I., Tveten G.M., Hagen T.W., Wiedeking M., Serot O., Boutoux G., Huu-Tai P. Chau, Méot V., and Roig O.

Subjects
Physics, QC1-999
Abstract

The surrogate-reaction method is an indirect way of determining cross sections for reactions that proceed through a compound nucleus. This technique may enable neutron-induced cross sections to be extracted for short-lived nuclei that otherwise cannot be measured. However, the validity of the surrogate method has to be investigated. In particular, the absence of a compound nucleus formation and the Jπ dependence of the decay probabilities may question the method. In this work we study the reactions 238U(d,p)239U, 238U(3He,t)238Np, 238U(3He,4He)237U as surrogates for neutron-induced reactions on 238U, 237Np and 236U, respectively, for which good quality data exist. The experimental set-up enabled the measurement of fission and gamma-decay probabilities. The first results are hereby presented.

Published
2013
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24. γ-Ray Studies of Induced Fission 12C+238U

Author

Houry, M., primary, Theisen, Ch., additional, Lucas, R., additional, Becker, F., additional, Korten, W., additional, Le Coz, Y., additional, Barreau, G., additional, Doan, T. P., additional, Durell, J., additional, Grimwood, D., additional, Roach, A., additional, Smith, A. G., additional, Varley, B. J., additional, Ethvignot, Th., additional, Deloncle, I., additional, Porquet, M. G., additional, Astier, A., additional, Perries, S., additional, and Redon, N., additional

Published
2000
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25. Determination of the 233Pa(n, f) reaction cross section from 0.5 to 10 MeV neutron energy using the transfer reaction 232Th( 3He, p) 234Pa

Author

Petit, M., Aiche, M., Barreau, G., Boyer, S., Carjan, N., Czajkowski, S., Dassié, D., Grosjean, C., Guiral, A., Haas, B., Karamanis, D., Misicu, S., Rizea, C., Saintamon, F., Andriamonje, S., Bouchez, E., Gunsing, F., Hurstel, A., Lecoz, Y., Lucas, R., Theisen, Ch., Billebaud, A., Perrot, L., and Bauge, E.

Published
2004
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27. Neutron-induced cross sections of actinides via the surrogate-reaction method

Author

Tveten G. M., Tsekhanovich I., Siem S., Rose S., Renstrøm T., Matarranz J., Lebois M., Larsen A. C., Guttormsen M., Gunsing F., Giacoppo F., Czajkowski S., Companis I., Barreau G., Wilson J. N., Görgen A., Tornyi T., Mathieu L., Aiche M., Jurado B., Ducasse Q., Hagen T. W., Wiedeking M., Serot O., Boutoux G., Chau P., Méot V., and Roig O.

Subjects
Physics, QC1-999
Abstract

The surrogate-reaction method is an indirect way of determining cross sections for reactions that proceed through a compound nucleus. This technique may enable neutron-induced cross sections to be extracted for short-lived nuclei that otherwise cannot be measured. However, the validity of the surrogate method for extracting capture cross sections has to be investigated. In this work we study the reactions 238U(d,p)239U, 238U(3He,t)238Np, 238U(3He,4He)237U as surrogates for neutroninduced reactions on 238U, 237Np and 236U, respectively, for which good quality data exist. The experimental set-up enabled the measurement of fission and gamma-decay probabilities. First results are presented and discussed.

Published
2013
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30. Evolution of isotopic fission-fragment yields with excitation energy

Author

Bazin D., Bastin B., Barreau G., Bacri C.-O., Amthor A.M., Audouin L., Tarasov O.B., Schmidt K.-H, Farget F., Derkx X., Caamaño M., Delaune O., Benlliure J., Blank B., Cacères L., Casarejos E., Fernández-Domínguez B., Gaudefroy L., Golabek C., Grévy S., Jurado B., Kamalou O., Lemasson A., Lukyanov S.M., Mittig W., Morrissey D.J., Navin A., Pereira J., Perrot L., Rejmund M., Roger T., Saint-Laurent M.G., Savajols H., Schmitt C., Sherrill B.M., Stodel C., Taieb J., Thomas J.C., and Villari A.C.C.

Subjects
Physics, QC1-999
Abstract

Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism.

Published
2012
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31. Measurement of neutron capture and fission cross sections of 233U in the resonance region

Author

Tsekhanovich I., Plompen A.J.M., Simutkin V., Haas B., Jurado B., Boutoux G., Czajkowski S., Schillebeeckx P., Barreau G., Mathieu L., Kessedjian G., Companis I., and Aïche M.

Subjects
Physics, QC1-999
Abstract

In the framework of studies concerning new fuel cycles and nuclear wastes incineration experimental data of the α ratio between capture and fission cross sections of 233U reactions play an important role in the Th/U cycle. The safety evaluation and the detailed performance assessment for the generation IV nuclear-energy system based on 232Th cycle strongly depend on this ratio. Since the current data are scarce and sometimes contradictory, new experimental studies are required. The measurement will take place at the neutron time-of-flight facility GELINA at Geel, designed to perform neutron cross section measurements with high incident neutron-energy resolution. A dedicated high efficiency fission ionization chamber (IC) as fission fragment detector and six C6D6 liquid scintilators sensitive to γ-rays and neutrons will be used. The method, based on the IC energy response study, allowing to distinguish between gammas originating from fission and capture, in the resonance region, will be presented.

Published
2012
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32. Neutron-induced cross sections of short-lived nuclei via the surrogate reaction method

Author

Tassan-Got L., Gunsing F., Sérot O., Matea I., Théroine C., Derkx X., Romain P., Taieb J., Morel P., Pillet N., Gaudefroy L., Faul T., Daugas J.M., Bauge E., Burke J.T., Czajkowski S., Companis I., Capellan N., Barreau G., Mathieu L., Aïche M., Roig O., Méot V., Jurado B., and Boutoux G.

Subjects
Physics, QC1-999
Abstract

The measurement of neutron-induced cross sections of short-lived nuclei is extremely difficult due to the radioactivity of the samples. The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This method presents the advantage that the target material can be stable or less radioactive than the material required for a neutron-induced measurement. We have successfully used the surrogate reaction method to extract neutron-induced fission cross sections of various short-lived actinides. In this work, we investigate whether this technique can be used to determine neutron-induced capture cross sections in the rare-earth region.

Published
2012
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33. Neutron-induced cross sections of short-lived nuclei via the surrogate reaction method

Author

Morel P., Gaudefroy L., Faul T., Daugas J.M., Bauge E., Burke J.T., Czajkowski S., Companis I., Capellan N., Barreau G., Mathieu L., Aïche M., Roig O., Méot V., Jurado B., Boutoux G., Pillet N., Romain P., Taieb J., Théroine C., Derkx X., Sérot O., Matea I., Tassan-Got L., and Gunsing F.

Subjects
Physics, QC1-999
Abstract

The measurement of neutron-induced cross sections of short-lived nuclei is extremely difficult due to the radioactivity of the samples. The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This method presents the advantage that the target material can be stable or less radioactive than the material required for a neutron-induced measurement. We have successfully used the surrogate reaction method to extract neutron-induced fission cross sections of various short-lived actinides. In this work, we investigate whether this technique can be used to determine neutron-induced capture cross sections in the rare-earth region.

Published
2011
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34. Neutron-induced capture cross sections via the surrogate reaction method

Author

Pillet N., Morel P., Méot V., Gaudefroy L., Faul T., Daugas J.M., Bauge E., Bail A., Mathieu L., Haas B., Dassié D., Czajkowski S., Companis I., Capellan N., Barreau G., Jurado B., Boutoux G., Aïche M., Roig O., Taieb J., Théroine C., Sérot O., Gunsing F., Burke J.T., Derkx X., and Tassan-Got L.

Subjects
Physics, QC1-999
Abstract

The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. In this method, the compound nucleus is produced via an alternative (surrogate) reaction and its decay (by fission, gamma or neutron emission) is measured in coincidence with the outgoing appropriate charged particle. This technique has enabled neutron-induced cross sections to be extracted for nuclear reactions on short-lived nuclei that otherwise could not be measured. The CENBG collaboration has successfully applied this technique to determine the neutron-induced fission cross sections of several short-lived nuclei such as 233Pa, 242,243Cm and 241Am. These data are very important for the development of the Th/U cycle and for minor actinide transmutation. We currently investigate whether this powerful technique can also be used to determine the neutron-induced capture cross sections. For this purpose we will use the surrogate reaction 174Yb(3He,pγ)176Lu to infer the well known 175Lu(n,γ) cross section and compare the results with the directly measured neutron-induced data. The experimental set-up and the first results will be presented. We will also discuss our future plans to use the surrogate method for extracting actinides (n,γ) cross sections.

Published
2010
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35. Neutron-induced capture cross sections of short-lived actinides with the surrogate reaction method

Author

Gunsing F., Bauge E., Sérot O., Faul T., Pillet N., Taieb J., Gaudefroy L., Roig O., Méot V., Haas B., Dassie D., Czajkowski S., Matthieu L., Barreau G., Jurado B., Boutoux G., and Aïche M.

Subjects
Physics, QC1-999
Abstract

Determination of neutron-capture cross sections of short-lived nuclei is opening the way to understand and clarify the properties of many nuclei of interest for nuclear structure physics, nuclear astrophysics and particularly for transmutation of nuclear wastes. The surrogate approach is well-recognized as a potentially very useful method to extract neutron cross sections for low-energy compound-nuclear reactions and to overcome the difficulties related to the target radioactivity. In this work we will assess where we stand on these neutron-capture cross section measurements and how we can achieve the short-lived Minor Actinides nuclei involved in the nuclear fuel cycle. The CENBG collaboration applied the surrogate method to determine the neutron-capture cross section of 233Pa (T1/2 = 27 d). The 233Pa (n,γ) cross section is then deduced from the measured gamma decay probability of 234Pa compound nucleus formed via the surrogate 232Th(3He,p) reaction channel. The obtained cross section data, covering the neutron energy range 0.1 to 1 MeV, have been compared with the predictions of the Hauser-Feshbach statistical model. The importance of establishing benchmarks is stressed for the minor actinides region. However, the lack of desired targets led us to propose recently the 174Yb (3He,pγ) reaction as a surrogate reaction for the (n,γ) predetermined benchmark cross section of 175Lu. An overview of the experimental setup combining gamma ray detectors such as Ge and C6D6 in coincidence with light charged particles ΔE-E Telescopes will be presented and preliminary results will be discussed.

Published
2010
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36. Neutron-induced fission cross sections of short-lived actinides with the surrogate reaction method

Author

Janssens R.V.F., Greene J.P., Ahmad I., Perrot L., Billebaud A., Bauge E., Sérot O., Theisen Ch., Lucas R., Lecoz Y., Hürstel A., Gunsing F., Bouchez E., Berthoumieux E., Andriamonje S., Wilson J.N., Tassan-Got L., Capellan N., Audouin L., Santiamon F., Rizea C., Misicu S., Mathieu L., Karamanis D., Haas B., Guiral A., Grosjean C., Dassie D., Czajkowski S., Carjan N., Boyer S., Barreau G., Bidaud A., Petit M., Aïche M., Jurado B., and Kessedjian G.

Subjects
Physics, QC1-999
Abstract

We present a review of the fission cross section measurements made by the CENBG collaboration over the last years using the surrogate reaction method. For example the neutron-induced fission cross sections of 233Pa(T1/2 = 27 d), 242Cm(T1/2 d) and 243Cm(T1/2 y) have been obtained by our group with this technique. The advantages and the difficulties of the surrogate method are discussed. Special attention is paid to the comparison between cross sections measured with the surrogate method and those obtained directly with neutrons at low energies. This comparison provides information on possible differences between the spin-parity distributions achieved in the two methods.

Published
2010
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37. Minor actinide fission induced by multi-nucleon transfer reaction in inverse kinematics

Author

Taieb J., Schmitt C., Roger T., Shrivastava A., Rejmund M., Navin A., Lemasson A., Golabek C., Jurado B., Gaudefroy L., Fernández-Domínguez B., Casarejos E., Barreau G., Benlliure J., Bacri C.-O., Audouin L., Schmidt K.-H., Caamaño M., Rejmund F., and Derkx X.

Subjects
Physics, QC1-999
Abstract

In the framework of nuclear waste incineration and design of new generation nuclear reactors, experimental data on fission probabilities and on fission fragment yields of minor actinides are crucial to design prototypes. Transfer-induced fission has proven to be an efficient method to study fission probabilities of actinides which cannot be investigated with standard techniques due to their high radioactivity. We report on the preliminary results of an experiment performed at GANIL that investigates fission probabilities with multi-nucleon transfer reactions in inverse kinematics between a 238U beam on a 12C target. Actinides from U to Cm were produced with an excitation energy range from 0 to 30 MeV. In addition, inverse kinematics allowed to characterize the fission fragments in mass and charge. A key point of the analysis resides in the identification of the actinides produced in the different transfer channels. The new annular telescope SPIDER was used to tag the target-like recoil nucleus of the transfer reaction and to determine the excitation energy of the actinide. The fission probability for each transfer channel is accessible and the preliminary results for 238U are promising.

Published
2010
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43. The cosi fan tutte project

Author

Oed, A., Perrin, P., Gönnenwein, F., Nifenecker, H., Geltenbort, P., Barreau, G., Ristori, C., Ehlers, J., editor, Hepp, K., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Zittartz, J., editor, David, Peter, editor, Mayer-Kuckuk, Theo, editor, and van der Woude, Adriaan, editor

Published
1982
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44. Study of the 238U(d,p) surrogate reaction via the simultaneous measurement of gamma-decay and fission probabilities

Author

Ducasse, Q., Jurado, B., Aïche, M., Marini, P., Mathieu, L., Görgen, A., Guttormsen, M., Larsen, A. C., Tornyi, T., Wilson, J. N., Barreau, G., Boutoux, G., Czajkowski, S., Giacoppo, F., Gunsing, F., Hagen, T. W., Lebois, M., Lei, J., Méot, V., Morillon, B., Moro, A., Renstrøm, T., Roig, O., Rose, S. J., Serot, Olivier, Siem, S., Tsekhanovich, I., Tveten, G. M., Wiedeking, M., Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

We investigated the 238U(d,p) reaction as a surrogate for the n + 238U reaction. For this purpose we measured for the first time the gamma-decay and fission probabilities of 239U* simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuum-discretized coupled-channels and distorted-wave Born approximations were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. In the region where the fission and gamma-decay probabilities compete, the corrected fission probability is in agreement with neutron-induced data, whereas the gamma-decay probability is much higher than the neutron-induced data. The performed statistical-model calculations are not able to explain these results., Includes modifications due to referee remarks

Published
2016

45. First results with DIAMANT and EUROGAM

Author

Aiche, M., Aléonard, M.M., Barreau, G., Bourgine, F., Brondi, A., Cabaussel-Sellam, D., Curien, D., Chemin, J.F., Goudour, J.P., Harston, M., La Rana, G., Moro, R., Scheurer, J.N., and Vardaci, E.

Published
1997
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46. Fission probabilities of Am242,Cm243, and Cm244 induced by transfer reactions

Author

Kessedjian, G., Jurado, B., Barreau, G., Marini, P., Mathieu, L., Tsekhanovich, I., Aiche, M., Boutoux, G., Czajkowski, S., Ducasse, Q., Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), and Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, Physics::Atomic and Molecular Clusters, Nuclear Experiment
Abstract

International audience; We have measured the fission probabilities of Am242,Cm243, and Cm244 induced by the transfer reactions Am243(He3,He4),Am243(He3,t), and Am243(He3,d), respectively. The details of the experimental procedure and a rigorous uncertainty analysis, including a correlation matrix, are presented. For Cm243 our data show clear structures well below the fission threshold. To our knowledge, it is the first time that these structures have been observed for this nucleus. We have compared the measured fission probabilities to calculations based on the statistical model to obtain information on the fission barriers of the produced fissioning nuclei.

Published
2015

48. The Neutrons for Science Facility at SPIRAL-2

Author

Ledoux, X., Aïche, M., Avrigeanu, M., Avrigeanu, V., Audouin, L., Balanzat, E., Ban-détat, B., Ban, G., Barreau, G., Bauge, E., Bélier, G., Bem, P., Blideanu, V., Borcea, C., Bouffard, S., Caillaud, T., Chatillon, A., Czajkowski, S., Dessagne, P., Doré, D., Fallot, M., Farget, F., Fischer, U., Giot, L., Granier, T., Guillous, S., Gunsing, F., Gustavsson, C., Jacquot, B., Jansson, K., Jurado, B., Kerveno, M., Klix, A., Landoas, O., Lecolley, F.R., Lecouey, J.L., Majerle, M., Marie, N., Materna, T., Mrazek, J., Negoita, F., Novak, J., Oberstedt, S., Oberstedt, A., Panebianco, S., Perrot, L., Plompen, A.J.M., Pomp, S., Ramillon, J.M., Ridikas, D., Rossé, B., Rudolf, G., Serot, O., Simakov, S.P., Simeckova, E., Smith, A.G., Sublet, J.C., Taieb, J., Tassan-Got, L., Tarrio, D., Takibayev, A., Thfoin, I., Tsekhanovich, I., and Varignon, C.

Published
2014
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49. Neutron-induced Cross Sections of Actinides via the Surrogate-reaction Method

Author

Ducasse, Q., Jurado, B., Aiche, M., Mathieu, L., Tornyi, T., Görgen, A., Wilson, J.N., Barreau, G., Companis, I., Czajkowski, S., Giacoppo, F., Gunsing, F., Guttormsen, M., Larsen, A.C., Lebois, M., Matarranz, J., Renstrøm, T., Rose, S., Siem, S., Tsekhanovich, I., Tveten, G.M., Hagen, T.W., Wiedeking, M., Serot, O., Boutoux, G., Chau, P., Méot, V., and Roig, O.

Published
2014
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50. First simultaneous measurement of fission and gamma probabilities of 237U and 239Np via surrogate reactions

Author

Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Marini, P., Ducasse, Q., Jurado, B., Aiche, M., Mathieu, L., Barreau, G., Moro Muñoz, Antonio Matías, Lei, Jin, Oberstedt, A., Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Marini, P., Ducasse, Q., Jurado, B., Aiche, M., Mathieu, L., Barreau, G., Moro Muñoz, Antonio Matías, Lei, Jin, and Oberstedt, A.

Abstract

Fission and gamma decay probabilities of 237U and 239Np have been measured, for the first time simultaneously in dedicated experiments, via the surrogate reactions 238U(3He, 4He) and 238U(3He,d), respectively. While a good agreement between our data and neutron-induced data is found for fission probabilities, gamma decay probabilities are several times higher than the corresponding neutron-induced data for each studied nucleus. We study the role of the different spin distributions populated in the surrogate and neutron-induced reactions. The compound nucleus spin distribution populated in the surrogate reaction is extracted from the measured gamma-decay probabilities, and used as input parameter in the statistical model to predict fission probabilities to be compared to our data. A strong disagreement between our data and the prediction is obtained. Preliminary results from an additional dedicated experiment confirm the observed discrepancies, indicating the need of a better understanding of the formation and decay processes of the compound nucleus.

Published
2016

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