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1. Observation of excited states in the neutron-rich nucleus Br89

Author

B. M. Nyakó, J. Timár, M. Csatlós, Zs. Dombrádi, A. J. Krasznahorkay, I. Kuti, D. Sohler, T. G. Tornyi, M. Czerwiński, T. Rząca-Urban, W. Urban, L. Atanasova, D. L. Balabanski, K. Sieja, A. Blanc, G. de France, M. Jentschel, U. Köster, P. Mutti, G. S. Simpson, T. Soldner, C. A. Ur, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear physics, medicine.anatomical_structure, 010308 nuclear & particles physics, Excited state, 0103 physical sciences, medicine, Neutron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, 01 natural sciences, Nucleus
Abstract

International audience; Excited states of the neutron-rich Br89 have been observed for the first time. They were populated in cold-neutron induced fission of U235 at the PF1B facility of the Institut Laue-Langevin, Grenoble. The measurement of γ radiation following fission has been performed using the EXILL array of Ge detectors. The observed level structure looks similar to the yrast level structure of Br87. Large valence space shell model calculations performed for Br89 confirmed this similarity. Comparison of the observed πg9/2 band with the results of the shell model calculations provides information on the evolution of collectivity in this region.

Published
2021

2. The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus 133Sb

Author

B. Fornal, Alison Bruce, G. Benzoni, W. Korten, Raymond J. Carroll, R. Lozeva, Zs. Podolyák, G. Bocchi, A. Nannini, D. R. Napoli, B. Olaizola, Henryk Mach, J. Jolie, D. Mengoni, G. S. Simpson, V. Vedia, D. Bazzacco, Michael Jentschel, F. Didierjean, B. Belvito, N. Saed-Samii, C. A. Ur, N. Cieplicka-Oryǹczak, B. Melon, W. Urban, J.-M. Régis, Torsten Soldner, P. H. Regan, N. Marginean, F. C. L. Crespi, V. Paziy, L. M. Fraile, C. Michelagnoli, B. Szpak, B. Million, T. Kröll, Aurelien Blanc, P. Mutti, A. Bracco, Ulli Köster, Pier Francesco Bortignon, S. Leoni, Gianluca Colò, S. Bottoni, S. Lalkovski, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, Large Ge array, Fission, Neutron induced fission, FOS: Physical sciences, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), Gamma spectroscopy, Nuclear state lifetime, Particle-core couplings, 0103 physical sciences, medicine, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Valence (chemistry), 010308 nuclear & particles physics, Yrast, lcsh:QC1-999, medicine.anatomical_structure, Excited state, Física nuclear, Atomic physics, Nucleus, Order of magnitude, lcsh:Physics
Abstract

The gamma-ray decay of excited states of the one-valence-proton nucleus Sb-133 has been studied using cold-neutron induced fission of U-235 and Pu-241 targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between gamma-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 mu s isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr3(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus Sn-132 and the valence proton, using Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.

Published
2016

3. Shape coexistence in the odd-odd nucleus Y98 : The role of the g9/2 neutron extruder

Author

W. Urban, M. Czerwiński, J. Kurpeta, T. Rząca-Urban, J. Wiśniewski, T. Materna, Ł. W. Iskra, A. G. Smith, I. Ahmad, A. Blanc, H. Faust, U. Köster, M. Jentschel, P. Mutti, T. Soldner, G. S. Simpson, J. A. Pinston, G. de France, C. A. Ur, V.-V. Elomaa, T. Eronen, J. Hakala, A. Jokinen, A. Kankainen, I. D. Moore, J. Rissanen, A. Saastamoinen, J. Szerypo, C. Weber, and J. Äystö

Subjects
Physics, Large deformation, 010308 nuclear & particles physics, 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Neutron, Gammasphere, Atomic physics, 010306 general physics, Spin (physics), Spectroscopy, Energy (signal processing), Spontaneous fission
Abstract

Excited states in $^{98}\mathrm{Y}$, populated in neutron-induced fission of $^{235}\mathrm{U}$ and in spontaneous fission of $^{248}\mathrm{Cm}$ and $^{252}\mathrm{Cf}$, have been studied by means of $\ensuremath{\gamma}$ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in $^{98}\mathrm{Y}$: a deformed one with ${T}_{1/2}=180(7)$ ns and a rotational band on top of it, and a spherical one with ${T}_{1/2}=0.45(15)\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\text{s}$, analogous to the ${8}^{+}$ isomer in $^{96}\mathrm{Y}$, corresponding to the ${(\ensuremath{\nu}{g}_{7/2},\ensuremath{\pi}{g}_{9/2})}_{{8}^{+}}$ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in $^{98}\mathrm{Y}$. This result and the studies of excited levels in $^{98}\mathrm{Zr}$, populated in ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of the isomer, indicate a new spin-parity, ${I}^{\ensuremath{\pi}}={(7)}^{+}$ for the isomer. The high spin and the decay properties of this isomer suggest the presence of the $9/{2}^{+}[404]$ neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the $\ensuremath{\nu}{g}_{7/2}\phantom{\rule{0.16em}{0ex}}\text{\ensuremath{-}}\phantom{\rule{0.16em}{0ex}}\ensuremath{\pi}{g}_{9/2}$ interaction (the spin-orbit-partner, or SOP, mechanism).

Published
2017

4. Abrupt shape transition at neutron number N=60 : B(E2) values in Sr94,96,98 from fast γ−γ timing

Author

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

Subjects
Physics, Fission products, Proton, Isotope, 010308 nuclear & particles physics, Fission, Yrast, Nuclear Theory, Monte Carlo method, 7. Clean energy, 01 natural sciences, Nuclear physics, 13. Climate action, Neutron number, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Lifetimes of low-lying yrast states in neutron-rich 94,96,98Sr have been measured by Germanium-gated γ−γ fast timing with LaBr3(Ce) detectors using the EXILL&FATIMA spectrometer at the Institut Laue-Langevin. Sr fission products were generated using cold-neutron-induced fission of 235U and stopped almost instantaneously within the thick target. The experimental B(E2) values are compared with results of Monte Carlo shell-model calculations made without truncation on the occupation numbers of the orbits spanned by eight proton and eight neutron orbits and show good agreement. Similarly to the Zr isotopes, the abrupt shape transition in the Sr isotopes near neutron number N=60 is identified as being caused by many-proton excitations to its g9/2 orbit.

Published
2017

5. EXOGAM at the ILL: the EXILL campaign

Author

G. de France, A. Blanc, F. Drouet, M. Jentschel, U. Köster, P. Mutti, J.M. Régis, G. Simpson, T. Soldner, O. Stezowski, C.A. Ur, W. Urban, A. Vancrayenest, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, History, 010308 nuclear & particles physics, Radiative capture, Nuclear Theory, Measure (physics), chemistry.chemical_element, Germanium, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Computer Science Applications, Education, Complement (complexity), Nuclear physics, chemistry, 0103 physical sciences, Neutron, 010306 general physics, Spectroscopy, Nuclear Experiment
Abstract

International audience; A combination of germanium detectors has been installed at the PF1B neutronguide of the ILL to perform the prompt spectroscopy of neutron-rich nuclei produced in theneutron-capture induced-fission of 235U and 241Pu. Radiative capture reactions on rare targetshave also been performed. LaBr3 detectors from the FATIMA collaboration have also beeninstalled in complement with the EXOGAM clovers to measure lifetimes of low-lying excitedstates. The measured characteristics indicate very good performances of the overall setup. Somerecent results will be discussed.

Published
2017

6. Half-life of the15/2+state ofI135: A test ofE2seniority relations

Author

P. Spagnoletti, G. S. Simpson, R. Carroll, J.-M. Régis, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, G. de France, C. A. Ur, W. Urban, A. M. Bruce, F. Drouet, L. M. Fraile, L. P. Gaffney, D. G. Ghită, S. Ilieva, J. Jolie, W. Korten, T. Kröll, C. Larijarni, S. Lalkovski, R. Lică, H. Mach, N. Mărginean, V. Paziy, Zs. Podolyák, P. H. Regan, M. Scheck, N. Saed-Samii, G. Thiamova, C. Townsley, A. Vancraeyenest, V. Vedia, A. Gargano, and P. Van Isacker

Subjects
Physics, 010308 nuclear & particles physics, Component (thermodynamics), Fission, Operator (physics), Half-life, Value (computer science), State (functional analysis), 7. Clean energy, 01 natural sciences, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, medicine, Seniority, Atomic physics, 010306 general physics, Nucleus
Abstract

The half-life of the 15/2+ 1 state of the 3-valence-proton nucleus 135I has been measured to be 1.74(8) ns using the EXILL-FATIMA mixed array of Ge and LaBr3 detectors. The nuclei were produced following the cold neutron-induced fission of a 235U target at the PF1B beam line of the Institut Laue-Langevin. The extracted B(E2; 15/2+ → 11/2+) value enabled a test of seniority relations for the first time between E2 transition rates. Large-scale shell-model calculations were performed for 134Te and 135I, and reinterpreted in a single-orbit approach. The results show that the two-body component of the E2 operator can be large whereas energy shifts due to the three-body component of the effective interaction are small.

Published
2017

7. Identification of excited states and collectivity in $^{88}$Se

Author

I. N. Gratchev, G. S. Simpson, G. Thiamova, M. Ramdhane, K. Sieja, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, G. de France, C. A. Ur, W. Urban, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Laue-Langevin (ILL), ILL, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Decay scheme, 010308 nuclear & particles physics, Fission, Deformation (meteorology), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, medicine.anatomical_structure, Excited state, 0103 physical sciences, Quadrupole, medicine, 010306 general physics, Nucleus, Beam (structure)
Abstract

International audience; The γ decays of excited states in the very neutron-rich nucleus Se88 have been observed following the neutron-induced fission of U235. The measurement was performed using the EXILL array of Ge detectors at the PF1B cold-neutron beam facility of the Institut Laue-Langevin, Grenoble. The level scheme of Se88 was established using γ-γ-γ coincidences. A low (21+) energy hints at the onset of quadrupole deformation, and the identification of possible members of a (22+) band provide evidence for γ vibrations. Shell-model calculations using a Ni78 core reproduce the decay scheme well. Equivalent deformation and B(E2) values have previously been predicted for Se88 using pseudo-SU(3), shell-model, and beyond mean-field frameworks implying that interactions between particles in the πf5/2p and νsd orbits are mostly responsible for the collectivity present.

Published
2017

8. Medium and high spin structure in the $^{94}$Y isotope produced in fission induced by cold neutrons

Author

Ł W Iskra, B Fornal, S Leoni, G Bocchi, A Blanc, S Bottoni, N Cieplicka-Oryńczak, M Jentschel, U Köster, C Michelagnoli, P Mutti, T Soldner, G de France, G S Simpson, C A Ur, W Urban, Institut Laue-Langevin (ILL), ILL, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)

Subjects
Physics, Cold fission, Cluster decay, Isotope, 010308 nuclear & particles physics, Fission, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Fission product yield, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Condensed Matter Physics, 7. Clean energy, 01 natural sciences, Fast fission, Atomic and Molecular Physics, and Optics, Nuclear physics, 0103 physical sciences, Neutron, 010306 general physics, Mathematical Physics
Abstract

International audience; The level scheme of the neutron-rich 94Y isotope has been extended up to the 5324 keV excitation energy. During the analysis, a structure above the previously known (5+) isomer, at 1202 keV, was extended by employing multifold gamma-ray coincidence relationships measured with the EXILL array. For some of the new states, the spin-parity assignment has been proposed on the basis of gamma angular correlations and shell-model considerations. The newly identified structure is characteristic of spherical or nearly spherical configurations and no evidence for new isomers and rotational patterns was found.

Published
2017

9. Measurement of picosecond lifetimes in neutron-rich Xe isotopes

Author

S. Ilieva, Th. Kröll, J.-M. Régis, N. Saed-Samii, A. Blanc, A. M. Bruce, L. M. Fraile, G. de France, A.-L. Hartig, C. Henrich, A. Ignatov, M. Jentschel, J. Jolie, W. Korten, U. Köster, S. Lalkovski, R. Lozeva, H. Mach, N. Mărginean, P. Mutti, V. Paziy, P. H. Regan, G. S. Simpson, T. Soldner, M. Thürauf, C. A. Ur, W. Urban, N. Warr, Institut Laue-Langevin (ILL), ILL, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Fission, Nuclear Theory, chemistry.chemical_element, Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Xenon, chemistry, Neutron number, Excited state, 0103 physical sciences, Quadrupole, Neutron, Física nuclear, Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

EXILL&FATIMA campaign; International audience; Background: Lifetimes of nuclear excited states in fission fragments have been studied in the past followingisotope separation, thus giving access mainly to the fragments’ daughters and only to long-lived isomeric statesin the primary fragments. For the first time now, short-lived excited states in the primary fragments, producedin neutron-induced prompt fission of 235U and 241Pu, were studied within the EXILL&FATIMA campaign at theintense neutron-beam facility of the Institute Laue-Langevin in Grenoble.Purpose: We aim to investigate the quadrupole collective properties of neutron-rich even-even 138,140,142Xeisotopes lying between the double shell closure N = 82 and Z = 50 and a deformed region with octupolecollectivity.Method: The γ rays emitted from the excited fragments were detected with a mixed array consisting of 8 HPGeEXOGAM Clover detectors (EXILL) and 16 LaBr3(Ce) fast scintillators (FATIMA). The detector system hasthe unique ability to select the interesting fragment making use of the high resolution of the HPGe detectorsand determine subnanosecond lifetimes using the fast scintillators. For the analysis the generalized centroiddifference method was used.Results: We show that quadrupole collectivity increases smoothly with increasing neutron number above theclosed N = 82 neutron shell. Our measurements are complemented by state-of-the-art theory calculations basedon shell-model descriptions.Conclusions: The observed smooth increase in quadrupole collectivity is similar to the evolution seen in themeasured masses of the xenon isotopic chain and is well reproduced by theory. This behavior is in contrast tohigher Z even-even nuclei where abrupt change in deformation occurs around N = 90.

Published
2016

10. Average radiation widths of levels in natural xenon isotopes

Author

Pascal Archier, P. Mutti, Gilles Noguere, C. De Saint Jean, and Olivier Litaize

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Neutron resonance, chemistry.chemical_element, Radiation, Nuclear physics, Stable xenon, Xenon, Electron linear accelerator, Nuclear magnetic resonance, chemistry, Isotopes of xenon, Shape analysis (digital geometry)
Abstract

Average radiation widths 〈Γγ〉 for the stable xenon isotopes have been estimated using neutron resonance spectroscopic information deduced from high-resolution capture and transmission data measured at the electron linear accelerator GELINA of the Institute for Reference Materials and Measurements (IRMM) in Geel, Belgium. The combination of conventional Neutron Resonance Shape Analysis techniques (NRSA) with high-energy model calculations in a simple Bayesian learning method permit to calculate a consistent local systematic in the xenonʼs mass region (Z=54) from A=124 to A=136.

Published
2011

11. The γ-γ fast-timing technique and the EXILL&FATIMA campaign

Author

J.-M. Régis, G.S. Simpson, H. Mach, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, G. de France, C.A. Ur, W. Urban, J. Jolie, N. Saed-Samii, N. Warr, L.M. Fraile, V. Paziy, P.H. Regan, Zs. Podolyák, S. Lalkovski, A.M. Bruce, T. Kröll, W. Korten, and N. Marginean

Subjects
Physics, Fission products, 010308 nuclear & particles physics, Fission, QC1-999, Detector, Centroid, 01 natural sciences, Spectral line, Semiconductor detector, Nuclear physics, Excited state, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Spectroscopy
Abstract

At the Institut Laue-Langevin in Grenoble, germanium-gated γ-γ fast-timing lifetime measurements of nuclear excited states in neutron-rich nuclei have been performed within a prompt γ-ray spectroscopy experimental campaign. We report on results obtained from the cold-neutron induced fission of 235 U. The excited secondary fission products were stopped almost instantaneously within the thick target and the γ rays emitted were collected triggerlessly using the EXILL&FATIMA mixed array of HPGe and LaBr 3 (Ce) detectors. Precise lifetimes could be determined by analysing the γ-γ time difference spectra using the generalized centroid difference method. This picosecondsensitive method provides many advantages and is briefly explained. Still, the major source of systematic errors is related to the contribution of time-correlated Compton background. The EXILL&FATIMA results are discussed with respect to the typical energy-dependent timing behaviour of the background. According to the time response of the background, appropriate methods and a time correction for the sub-nanosecond regime are proposed.

Published
2018

12. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

Author

D. Bernard, C. Sage, A. Blanc, O. Serot, U. Köster, Olivier Litaize, P. Mutti, A. Chebboubi, H. Faust, Grégoire Kessedjian, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Laue-Langevin (ILL), and ILL

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, Fission, QC1-999, Mechanical engineering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, 7. Clean energy, Neutron temperature, Symmetry (physics), Characterization (materials science), Nuclear physics, 13. Climate action, Yield (chemistry), 0103 physical sciences, 010306 general physics, Nuclear Experiment, Analysis method
Abstract

International audience; The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

Published
2015

13. Test of the SO(6) selection rule in $^{196}$Pt using cold-neutron capture

Author

M. Pfeiffer, D. Wilmsen, Zs. Podolyák, R. Lica, Alison Bruce, F. Drouet, J.-M. Régis, W. Korten, A. Vancraeyenest, S. Kisyov, W. Urban, Ulli Köster, N. Saed-Samii, D. Ivanova, Aurelien Blanc, Michael Jentschel, A. Ignatov, J. Jolie, Torsten Soldner, G.S. Simpson, P. Mutti, Th. Kröll, V. Paziy, L. M. Fraile, P. H. Regan, N. Marginean, E. Wilson, N. Warr, C. A. Ur, Oliver J. Roberts, S. Lalkovski, Institut Laue-Langevin (ILL), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, ILL, 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Detector, State (functional analysis), Scintillator, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Collimated light, Nuclear physics, Neutron capture, Beamline, Interacting boson model, Atomic physics, Beam (structure), ComputingMilieux_MISCELLANEOUS
Abstract

At the PF1B cold-neutron beam line of the Institut Laue Langevin, the EXILL&FATIMA array, consisting of EXOGAM Ge detectors and fast LaBr3(Ce) scintillators, was used to perform fast electronic timing measurements after the 195Pt(n, γ) reaction using a highly collimated cold-neutron beam. An upper lifetime limit was obtained for the third 0 + state in 196Pt. As this state is the lowest state of the σ = N − 2 set of SO(6) states, the selection rule which forbids E2 transitions to the lower lying σ = N could be tested.

Published
2015

14. Measurement of the 210Po production induced by thermal neutron capture on 209Bi

Author

F. Marie, Alain Letourneau, Danas Ridikas, G. Fioni, and P. Mutti

Subjects
Nuclear reaction, Materials science, Analytical chemistry, Nuclear data, chemistry.chemical_element, Neutron temperature, Nuclear physics, Nuclear Energy and Engineering, chemistry, Neutron, Spallation, Gamma spectroscopy, Spectroscopy, Polonium
Abstract

A measurement of the polonium production in a solid Bi target, placed in a high thermal neutron flux of 2.3 10 13 n/cm 2 /s, was performed. Two different activation methods, based on α and γ spectroscopy, were used to cross check the results. Values of (16.08 ± 1.8) mb and (18.4 ± 0.9) mb for the 210 P o (i.e. 210gs Bi) formation cross section were obtained and a recommended value of (17.9 ± 0.8) mb was proposed. Our results are in disagreement with adopted cross section values in the main nuclear data libraries, namely smaller by 25% for 210gs Bi. These new values will account for more precise evaluations of 210 P o formation in moderated spallation targets containing 209 Bi.

Published
2006

15. Thermal neutron capture cross-section measurements of 243Am and 242Pu using the new mini-INCA - and -spectroscopy station

Author

B. Muhammad, O. Déruelle, P. Mutti, F. Marie, H. Faust, I. Almahamid, G. Fioni, Alain Letourneau, and Ch. Veyssiere

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Neutron capture, Nuclear transmutation, Neutron flux, Neutron cross section, Minor actinide, Neutron, Actinide, Spectroscopy, Instrumentation
Abstract

In the framework of the Mini-INCA project, dedicated to the study of Minor Actinide transmutation process in high neutron fluxes, an α - and γ -spectroscopy station has been developed and installed at the High Flux Reactor of the Laue-Langevin Institut. This set-up allows short irradiations as well as long irradiations in a high quasi-thermal neutron flux and post-irradiation spectroscopy analysis. It is well suited to measure precisely, in reference to 59 Co cross-section, neutron capture cross-sections, for all the actinides, in the thermal energy region. The first measurements using this set-up were done on 243 Am and 242 Pu isotopes. Cross-section values, at E n = 0.025 eV , were found to be ( 81.8 ± 3.6 ) b for 243 Am and ( 22.5 ± 1.1 ) b for 242 Pu. These values differ from evaluated data libraries by a factor of 9% and 17%, respectively, but are compatible with the most recent measurements, validating by the way the experimental apparatus.

Published
2006

16. Quantitative neutron capture resonance analysis verified with instrumental neutron activation analysis

Author

Menno Blaauw, P. Mutti, and H. Postma

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Neutron capture, Time of flight, Resonance analysis, Elemental analysis, Astrophysics::High Energy Astrophysical Phenomena, Dead time, Neutron activation analysis, Instrumentation, Resonance (particle physics), Doppler broadening
Abstract

The newly developed elemental analysis technique Neutron Resonance Capture Analysis (NRCA) was verified by analyzing a prehistoric bronze arrowhead with both NRCA and Instrumental Activation Analysis (INAA). In NRCA, elements are identified through their neutron resonance capture energies as determined through detection of prompt capture gamma-rays as a function of time of flight. The quantification is obtained from the resonance peak areas. Corrections are required for neutron-energy-dependent dead time and self-shielding, the latter also depending on Doppler broadening. The analysis program REFIT, of which the intended use is the determination of the resonance parameters, was used to this end. The agreement observed between INAA and NRCA results indicates that the NRCA results obtained are accurate.

Published
2003

17. Study of $^{41}$Ca via Cold Neutron Capture

Author

N. Cieplicka-Oryńczak, G. Bocchi, S. Leoni, B. Fornal, S. Bottoni, M. Jentschel, U. Köster, P. Mutti, T. Soldner, A. Blanc, G. De France, G.S. Simpson, A. Türler, W. Urban, C.A. Ur, Institut Laue-Langevin (ILL), Grand Accélérateur National d'Ions Lourds (GANIL), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear physics, Physics, Neutron capture, 010308 nuclear & particles physics, 540 Chemistry, 0103 physical sciences, 570 Life sciences, biology, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, 010306 general physics, 01 natural sciences
Abstract

International audience; The low-spin structure of the 41Ca isotope, populated by neutron capture, has been investigated by high resolution γ-spectroscopy techniques. The experiment was performed at the PF1B cold neutron facility at the Institut Laue–Langevin (Grenoble, France) employing the EXILL array, consisting of 46 HPGe crystals. Several new γ rays have been observed and two excited states were newly established.

Published
2017

18. Neutron-capture experiment on 77Se with EXILL at ILL Grenoble

Author

Ch. Lorenz, R. John, R. Massarczyk, R. Schwengner, A. Blanc, G. de France, M. Jentschel, U. Köster, P. Mutti, G. Simpson, T. Soldner, W. Urban, S. Valenta, T. Belgya, Institut Laue-Langevin (ILL), ILL, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Vernay, Emmanuelle, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Neutron capture, [PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Detector, gamma-spectroscopy, 030204 cardiovascular system & hematology, 7. Clean energy, 01 natural sciences, Engineering physics, Nuclear physics, 03 medical and health sciences, 0302 clinical medicine, 0103 physical sciences, Neutron, Detector array, Nuclear Experiment
Abstract

International audience; The neutron capture reaction at 77Se has been studied with cold neutrons in the course of the EXILL campaign at the high-flux reactor of the Institut Laue-Langevin Grenoble. A simulation of the detector array with Geant4 has been accomplished and evaluated. The detector response has been deduced and measured spectra were unfolded, which have been compared with simulations using γDex to determine strength functions.

Published
2014

19. From EXILL (EXogam at the ILL) to FIPPS (FIssion Product Prompt γ-ray Spectrometer)

Author

A. Blanc, A. Chebboubi, G. de France, F. Drouet, H. Faust, M. Jentschel, G. Kessedjian, U. Köster, S. Leoni, T. Materna, P. Mutti, S. Panebianco, C. Sage, G. Simpson, T. Soldner, C. A. Ur, W. Urban, A. Vancraeyenest, Institut Laue-Langevin (ILL), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, ILL, 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear fission product, Fission products, Spectrometer, Fission, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Neutron radiation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Collimated light, Nuclear physics, Neutron, Spectroscopy, Nuclear Experiment
Abstract

International audience; Within the EXILL campaign a large and efficient cluster of Ge-detectors was installed around a very well collimated neutron beam. This has allowed to carry out rather complete spectroscopic studies close to the line of stability using the (n,γ) reaction. Neutron rich isotopes were produced by neutron induced fission and prompt spectroscopy was carried out. The isotope selection in this setup was based on a partially known level scheme and the use of triple coincidences. The latter is limiting the statistical sensitivity in the case of weak production yields. Based on the experiences of these campaigns we are currently developing a new setup: FIPPS (FIssion Product Prompt Spectroscopy). This setup combines a collimated neutron beam, a highly efficient cluster of Ge detectors, a gas filled magnet and auxiliary detectors. The presence of the gas filled magnet will allow us to identify fission products directly and should give access to a new quality of studies if compared to the EXILL campaign. The EXILL campaign and the FIPPS project are presented.

Published
2014

20. Lifetime Measurements in Neutron-rich Xe Isotopes - Evolution of Quadrupole Collectivity Beyond $^{132}$Sn

Author

S. Ilieva, S. Bönig, A.-L. Hartig, C. Henrich, A. Ignatov, Th. Kröll, M. Thürauf, J. Jolie, J.-M. Régis, N. Saed-Samii, A. Blanc, G. de France, M. Jentschel, U. Köster, P. Mutti, G. S. Simpson, T. Soldner, W. Urban, N. Mǎrginean, C. A. Ur, H. Mach, L. M. Fraile, V. Paziy, P. H. Regan, A. M. Bruce, S. Lalkovski, W. Korten, Institut Laue-Langevin (ILL), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Isotope, Chemistry, Fission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Lifetimes of excited states, quadrupole collectivity, neutron-rich Xe isotopes, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, Picosecond, Excited state, Quadrupole, Neutron, MAGIC (telescope), Atomic physics, Nuclear Experiment, Spectroscopy
Abstract

EXILL&FATIMA and IS411 collaborations; International audience; Picosecond lifetimes of excited states in neutron-rich Xe isotopes were measured at the Institut Laue-Langevin via $\gamma$-ray spectroscopy of fission fragments from neutron-induced fission of 235U and 241Putargets. The data collected with the recently installed fast timing array FATIMA in combination withthe EXOGAM Ge array were analysed using the new generalized centroid difference method. Ouraim is to study the quadrupole and octupole collectivity, arising in the mass region beyond the doublymagic 132Sn, by means of transition probabilities. These can be calculated from the directly measuredlifetimes.

Published
2014

21. The EXILL campaign

Author

G DE FRANCE, A BLANC, F DROUET, M JENTSCHEL, U KÖSTER, P MUTTI, J M RÉGIS, G SIMPSON, T SOLDNER, O STEZOWSKI, S LEONI, W URBAN, A VANCRAYENEST, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut Laue-Langevin (ILL), ILL, 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), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), EXILL, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 23.20.Lv, 21.10.Pc, 21.10.Tg, 25.40.Lw, 25.85.Ec, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Radiative capture, General Physics and Astronomy, chemistry.chemical_element, Germanium, radiative capture, γ -ray spectroscopy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Spectral line, Nuclear physics, chemistry, neutron-rich nuclei, Excited state, neutron-induced fission, Neutron, Nuclear Experiment, Spectroscopy
Abstract

International audience; A combination of germanium detectors was installed at the PF1B neutron guide ofthe ILL to perform prompt spectroscopy of neutron-rich nuclei produced in the neutron-captureinduced-fission of $^{235}$U and ^${241}$Pu. In addition, La$Br_3$ detectors from the FATIMA Collaborationwere installed to complement with the EXOGAM clovers to measure lifetimes of low-lying excitedstates. The measured characteristics and online spectra indicate very good performances of theoverall set-up.

Published
2014

22. The stellar capture rate of 136Ba

Author

K. Athanassopulos, P. Mutti, H. Beer, and F. Corvi

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Range (particle radiation), Isotope, Nucleosynthesis, Astrophysics::High Energy Astrophysical Phenomena, Neutron cross section, High resolution, Atomic physics
Abstract

High resolution 136Ba(n,γ) measurements were carried out at GELINA and the capture areas of 184 resonances in the range 0.4–60 keV were derived. From these values the Maxwellian - averaged neutron capture cross section was calculated vs temperature kT from 5 to 50 keV. The results for this unbranched s-only isotope are discussed in the light of the recent models of s-process nucleosynthesis.

Published
1997

23. Neutron Capture of the Bottleneck Isotopes138Ba and208Pb,s‐Process Studies, and ther‐Process Abundance Distribution

Author

P. Mutti, F. Corvi, and H. Beer

Subjects
Physics, Nuclear physics, Nuclear reaction, Neutron capture, Isotope, Space and Planetary Science, Nucleosynthesis, Abundance (ecology), r-process, Neutron source, Astronomy and Astrophysics, Atomic physics, s-process
Abstract

The capture cross sections of 138Ba and 208Pb have been measured by time-of-—ight (TOF) at the electron linear accelerator GELINA in the energy range from 200 eV to 200 keV. The Maxwellian aver- aged capture (MAC) cross sections were determined versus temperature kT between 5 and 100 keV. The data were applied to carry out new parametric studies of the s-process. Two parameterized models were considered, pulsed s-process with one neutron source and double-pulsed s-process, the combined burning of two neutron sources. Through the s-process abundance distribution the complementary semiempirical p-process and r-process abundance distributions were determined. Especially the termination of the s-process was investigated. It was found that in the frame of the double-pulse s-process model only negli- gible amounts of 209Bi are synthesized. This would mean that bismuth is mainly an r-process element. Subject headings: atomic datamethods: laboratorynuclear reactions, nucleosynthesis, abundances Alls well that ends well.¨William Shakespeare All change is not growth, as all movement is not forward.¨Ellen Glasgow

Published
1997

24. Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL : the EXILL campaign

Author

A. Blanc, G. de France, F. Drouet, M. Jentschel, U. Köster, C. Mancuso, P. Mutti, J.M. Régis, G. Simpson, T. Soldner, C.A. Ur, W. Urban, A. Vancraeyenest, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), F. Farget, A. Chatillon, H. Faust, G. Fioni, D. Goutte, H. Goutte, ILL, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Fission, Physics::Instrumentation and Detectors, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, chemistry.chemical_element, Germanium, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, 01 natural sciences, 7. Clean energy, Spectral line, Nuclear physics, 0103 physical sciences, Neutron, 010306 general physics, Spectroscopy, Nuclear Experiment, ComputingMilieux_MISCELLANEOUS, Physics, 010308 nuclear & particles physics, Nuclear structure, Actinide, chemistry, Excited state, Atomic physics
Abstract

One way to explore exotic nuclei is to study their structure by performing γ-ray spectroscopy. At the ILL, we exploit a high neutron flux reactor to induce the cold fission of actinide targets. In this process, fission products that cannot be accessed using standard spontaneous fission sources are produced with a yield allowing their detailed study using high resolution γ-ray spectroscopy. This is what was pursued at the ILL with the EXILL (for EXOGAM at the ILL) campaign. In the present work, the EXILL setup and performance will be presented.

Published
2013

25. Isomeric ratio measurements with the ILL LOHENGRIN spectrometer

Author

U. Köster, Olivier Litaize, Grégoire Kessedjian, A. Chebboubi, C. Sage, A. Blanc, D. Bernard, P. Mutti, H. Faust, O. Méplan, O Serot, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Laue-Langevin (ILL), and ILL

Subjects
Spectrometer, 010308 nuclear & particles physics, Fission, Chemistry, Physics, QC1-999, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear reactor, 01 natural sciences, 7. Clean energy, Neutron damage, law.invention, Momentum, Nuclear physics, law, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Neutron, Physics::Chemical Physics, Nuclear Experiment, 010306 general physics
Abstract

International audience; The modelling of γ heating and neutron damage inside a nuclear reactor is essential to design the next generation of nuclear reactors. The determination of the fission fragment momentum is a key element to perform accurate calculations of the γ heating. One way to assess this information is to look at the isomeric ratio of different nuclei. According to the lifetime of the isomeric state, different experimental techniques were developed at the LOHENGRIN spectrometer. A focus on the measurement of isomeric ratios of 136I in neutron induced fission of 241Pu is presented. A discussion with the current assumptions used in the evaluation process for isomeric ratio is also shown.

Published
2016

26. Near-yrast Excitations in Nucleus $^{83\mskip -\thinmuskip }$As: Tracing the Deformation in the $^{78}$Ni Region

Author

P. Bączyk, W. Urban, D. Złotowska, M. Czerwiński, T. Rząca-Urban, M. Konieczka, A. Blanc, M. Jentschel, P. Mutti, U. Köster, T. Soldner, G. de France, G. Simpson, and C. Ur

Subjects
Physics, Fission, Astrophysics::High Energy Astrophysical Phenomena, Yrast, Nuclear Theory, Gamma ray, General Physics and Astronomy, Context (language use), Deformation (meteorology), Nuclear physics, medicine.anatomical_structure, medicine, Detector array, Nuclear Experiment, Spin (physics), Nucleus
Abstract

Medium-spin, yrast excitations in nucleus 83As have been studied in neutron-induced fission of 235U. The experiment took place at the Institut Laue-Langevin in Grenoble where gamma rays were registered using the EXILL detector array. Recently, we proposed new tentative (9=2+) spin assignment for 2777 keV level in 83As, which is now discussed in the context of deformation showing up in 78Ni region.

Published
2016

27. Isomers in fission fragments

Author

W. Urban, H. Faust, M. Jentschel, U. Köster, J. Krempel, Th. Materna, P. Mutti, T. Soldner, J. Genevey, J. A. Pinston, G. Simpson, T. Rza̧ca-Urban, A. Złomaniec, M. Łukasiewicz, K. Sieja, F. Nowacki, O. Dorvaux, B. J. P. Gall, B. Roux, J. A. Dare, J. L. Durell, A. G. Smith, B. J. Varley, I. Tsekhanovich, J. Jolie, A. Linnemann, A. Scherillo, R. Orlandi, J. F. Smith, I. Ahmad, Jan Jolie, Andreas Zilges, Nigel Warr, Andrey Blazhev, Institut Laue-Langevin (ILL), ILL, 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), Département Recherches Subatomiques (DRS-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), and Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Fission products, Cluster decay, 010308 nuclear & particles physics, Chemistry, Fission, Yrast, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, 0103 physical sciences, Neutron, Gammasphere, 010306 general physics, Spontaneous fission
Abstract

International audience; The structure of neutron‐rich nuclei produced as secondary fission fragments was investigated using the EUROGAM and GAMMASPHERE ACS arrays, the LOHENGRIN fission‐fragment mass separator and the FIFI fission‐fragment identifier. Fission products were populated in spontaneous fission of 248Cm and 252Cf and in thermal neutron‐induced fission of 233U, 235U and 241Pu at ILL Grenoble. Particularly useful in such studies are isomeric states, well populated in fission due to their yrast character, easy to detect due to their long half lives and easy to interpret because of their relatively simple composition. We discuss their role in studies of neutron‐rich nuclei, giving examples of isomers found in our recent experiments. A special type of K‐isomers, resulting from 'crossing' of extruder and intruder orbitals plays a role in the mechanism of a sudden onset of deformation in the A = 100 and A = 150 regions. We present evidence for these isomers in both regions. Possible further studies in this field are proposed.

Published
2008

28. Progress on the GAMS-6 double crystal γ-spectrometer

Author

Giovanni Mana, J. Krempel, B. Lauss, P. Mutti, M. Jentschel, and Peter Becker

Subjects
Physics, Spectrometer, Astrophysics::High Energy Astrophysical Phenomena, High resolution, Planck constant, Nuclear physics, Neutron capture, symbols.namesake, Wavelength, High flux, symbols, Double crystal, Crystal spectrometer, Nuclear Experiment
Abstract

Measuring the wavelength of gamma-rays emitted after a neutron capture reaction allows a direct determination of the molar Planck constant NAh. Currently these measurements are realized using the high resolution double crystal spectrometers GAMS4 and GAMS5 placed at the high flux reactor of the Institut Laue-Langevin in Grenoble, France. So far it was possible to achieve a relative uncertainty of 4 times 10-7. In this contribution we describe the progress in building a new generation crystal spectrometer, GAMS 6, which is meant to lower the uncertainty to the 10-8 level.

Published
2008

29. Measurement of neutron binding energy of 36Cl for a determination of NAh

Author

P. Mutti, B. Lauss, J. Krempel, Peter Becker, M. Jentschel, and Giovanni Mana

Subjects
Physics, Nuclear physics, symbols.namesake, Binding energy, Avogadro constant, symbols, Gamma ray, Nuclear binding energy, Neutron, Context (language use), Atomic physics, Planck constant, Atomic mass
Abstract

Precise wave length measurements of gamma rays emitted after thermal neutron capture reaction allow the determination of the neutron's binding energy within a nucleus. Comparing this energy to atomic mass measurements gives direct access to the molar Planck constant NAh. This result will be of utmost importance in the context of a re-definition of the kilogram via the Planck and the Avogadro constants. Having this in mind, any future measurement must yield a relative uncertainty of better then 5 times10-8. An essential step towards this goal is to demonstrate that there are no statistical limitations for such an experiment. In the present contribution we report on the results of the recently performed binding energy measurement on 36Cl using a modified version of the double flat crystal spectrometer GAMS4.

Published
2008

30. Resonance shape analysis of neutron capture measurements from xenon spherical samples

Author

Gilles Noguere, A. Brusegan, C. de Saint Jean, Olivier Litaize, F. Corvi, and P. Mutti

Subjects
Nuclear physics, Spherical model, Neutron capture, Xenon, Chemistry, Monte Carlo method, Cylinder, Nuclear data, chemistry.chemical_element, Scattering correction, Shape analysis (digital geometry)
Abstract

Techniques have been developed in the frame of the CONRAD Nuclear data analysis code in order to take into account the multiple scattering correction for capture yields. The resonance shape analysis of these capture data have to account for these corrections during the fitting procedure. Analytical formulae and Monte Carlo simulations can be performed through Multiple-Scattering-Correction module in the CONRAD code in order to estimate the differential and total capture yields. Monte Carlo method accounts for usual biasing techniques (implicite capture and Russian roulette). This experimental correction procedure is checked against other codes like REFIT and SAMMY which are extensively used for cylindrical sample analysis. In this work, xenon spherical samples have been studied. Capture and transmission measurements of gaseous samples have been performed at the GELINA facility of the Institute for Reference Materials and Measurements (IRMM) by P. Mutti, F. Corvi and A. Brusegan. For the capture measurements, spherical samples with diameter of 8cm were used. Due to the spherical shape of the sample, equivalent cylinder (h ≈ 5.33cm) was taken into account in SAMMY or REFIT analysis (spherical model is not implemented in these codes). These results are compared with analysis involving multiple scattering correction for spherical targets available in CONRAD.

Published
2007

31. Measurements of thermal fission and capture cross sections of minor actinides within the Mini-INCA project

Author

O. Bringer, I. AlMahamid, S. Chabod, F. Chartier, E. Dupont, A. Letourneau, P. Mutti, L. Oriol, S. Panebianco, and Christian Veyssière

Subjects
Nuclear physics, Nuclear reaction, Neutron capture, Nuclear transmutation, Chemistry, Fission, Nuclear data, Radioactive waste, Neutron, Actinide
Abstract

In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at CEA/DSM to determine optimal conditions for transmutation and incineration of Minor Actinides (MA) in high intensity neutron fluxes in the thermal region. Our experimental tool is based on alpha- and gamma-spectroscopy of irradiated samples and microscopic fission-chambers. It can provide both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials. The 232 Th, 237 Np, 241 Am, and 244 Cm transmutation chains have been explored in details, showing some discrepancies in comparison with evaluated data libraries but in overall good agreement with recent experimental data.

Published
2007

32. Fission studies by prompt gamma-ray spectrometry

Author

T. Materna, A. Letourneau, Ch. Amouroux, A. Marchix, O. Litaize, O. Sérot, D. Regnier, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, G. Simpson, S. Leoni, G. de France, W. Urban, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Laue-Langevin (ILL), ILL, 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), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Fissile material, 010308 nuclear & particles physics, Fission, QC1-999, Astrophysics::High Energy Astrophysical Phenomena, Detector, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Neutron radiation, 01 natural sciences, Coincidence, Nuclear physics, High flux, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, Gamma ray spectrometry
Abstract

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence 4.0; International audience; The feasibility of retrieving accurate fission observables with a Ge-detector array around a fissile target placed in a cold neutron beam was tested. In three measurement campaigns performed at ILL with the EXILL setup, 235U and 241Pu targets were placed in the high flux cold neutron beam available at the PF1B neutron guide. Gamma-rays following fission were detected by an array of 16 Ge detectors. In the following study, part of data was analyzed as a proof of principle. A set of yields belonging to the Kr-Ba pair were extracted using a gamma-gamma coincidence technique. Preliminary results were compared to the predictions of two phenomenological models: GEF and FIFRELIN.

Published
2015

33. Gamma-Ray Spectroscopy at the Institut Laue Langevin

Author

G. S. Simpson, P. Mutti, M. Jentschel, and H. G. Börner

Subjects
inorganic chemicals, Physics, Nuclear reaction, Spectrometer, Fission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Resolution (electron density), technology, industry, and agriculture, Gamma ray, Nuclear physics, biological sciences, lipids (amino acids, peptides, and proteins), Gamma spectroscopy, Neutron, Nuclear Experiment, Spectroscopy
Abstract

Some aspects of neutron‐induced gamma‐ray spectroscopy studies, as currently carried out at the high‐flux reactor of the Institut Laue Langevin (ILL), are discussed. Neutron‐induced fission allows us to study very neutron‐rich nuclei, using in‐pile and external target arrangements, respectively. The use of high‐resolution crystal spectrometers allows investigations of gamma rays with ppm resolution.

Published
2005

34. Accurate Wavelength Measurement of High-Energy Gamma Rays from the 35Cl(n,γ) Reactions

Author

T. Belgya, M. Jentshel, P. Mutti, H. G. Börner, and G. L. Molnár

Subjects
Physics, Nuclear physics, Wavelength, Decay scheme, Spectrometer, Astrophysics::High Energy Astrophysical Phenomena, Binding energy, Detector, Gamma ray, Gamma spectroscopy, Atomic physics, Radioactive decay
Abstract

The energies of eight gamma rays in the 36Cl level scheme have been measured with high precision using the 35Cl(n,γ) reaction and the GAMS4 spectrometer. From these energies, a skeleton decay scheme for 36Cl was constructed, and the binding energy of 36Cl was determined to higher precision than previously. It is shown that using this new information, binding energy determination from Ge detector experiments for other nuclei can also be made with higher precision than now available. The measurement of additional weaker 36Cl gamma rays is continuing.

Published
2005

35. New Kr Cross Sections and Astrophysical Constraints on Presolar Grains

Author

P. Mutti, H. Beer, R. Gallino, F. Corvi, and A. Brusegan

Subjects
Nuclear physics, Physics, Stars, chemistry, Nucleosynthesis, Metallicity, Presolar grains, Krypton, Isotopes of krypton, Nuclear data, chemistry.chemical_element, s-process
Abstract

A series of neutron‐capture cross‐section measurements on various krypton isotopes has been performed at the Geel Electron Linear Accelerator (GELINA). The total cross section of 84Kr and the capture cross section of 86Kr and 82Kr have been measured in the energy range from 0 up to 400 keV. Moreover, capture cross‐section data for 80Kr and 83Kr have been obtained for a limited energy range, namely from 0 up to 5 keV, from a natural krypton sample. The main goal of the measurement campaign was to provide reliable nuclear data for s‐process nucleosynthesis calculation. We performed a series of calculations for stars with mass from M = 1.5M⊙ to M = 3M⊙ and metallicity from solar down to 1/6 of solar with the aim to reproduce the krypton isotopic ratios found in silicon‐carbide grains.

Published
2005

36. Accurate Determination of Neutron Binding Energies

Author

Albert Henins, P. Mutti, M. Jentschel, Ernest G. Kessler, Maynard S. Dewey, and H. G. Börner

Subjects
Nuclear physics, symbols.namesake, Chemistry, Astrophysics::High Energy Astrophysical Phenomena, Binding energy, symbols, Nuclear binding energy, Neutron, Planck constant
Abstract

The combination of high‐precision gamma‐ray measurements with precision mass determinations allows determination of fundamental constants, such as the neutron mass and the molar Planck constant. The basic principle of these measurements will be discussed. Experimental results from measurements with 29Si, 36Cl, and 33S will be presented and used to discuss the current limitations of the measurements.

Published
2005

37. THERMAL NEUTRON CAPTURE BRANCHING RATIO OF 209BI USING A GAMMA-RAY TECHNIQUE

Author

A. Letourneau, E. Berthoumieux, H. Faust, G. Fioni, M. Fadil, H. Boerner, F. Marie, O. Deruelle, P. Schillebeeckx, Danas Ridikas, G. Simpson, F. Gunsing, P. Mutti, and L. Perrot

Subjects
Nuclear physics, Materials science, Branching fraction, Neutron stimulated emission computed tomography, Gamma ray, Thermal neutron capture
Published
2003

38. First results of the (n,γ) EXILL campaigns at the Institut Laue Langevin using EXOGAM and FATIMA

Author

J Jolie, J-M Régis, D Wilmsen, S Ahmed, M Pfeiffer, N Saed-Samii, N Warr, A Blanc, M Jentschel, U Köster, P Mutti, T Soldner, G Simpson, G de France, W Urban, A M Bruce, O J Roberts, L M Fraile, V Paziy, A Ignatov, S Ilieva, Th Kröll, M Scheck, M Thürauf, D Ivanova, S Kisyov, S Lalkovski, Zs Podolyak, P H Regan, W Korten, D Habs, P G Thirolf, C A Ur, Institut Laue-Langevin (ILL), ILL, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), EXOGAM, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear physics, History, Optics, business.industry, Scintillator, Neutron radiation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], business, Computer Science Applications, Education
Abstract

At the PF1B cold neutron beam line at the Institut Laue Langevin the EXILL array consisting of EXOGAM, GASP and LOHENGRIN detectors was used to perform (n,γ) measurements under very high coincidence rates. About ten different reactions were then measured in autumn 2012. In spring 2013 the EXOGAM array was combined with 16 LaBr3(Ce) scintillators in the FATIMA@EXILL campaign for the measurement of lifetimes using the generalised centroid difference method. We report on the properties of both set-ups and present first results on Pt isotopes from both campaigns.

Published
2014

41. Neutron capture cross sections of [sup 84,86]Kr and their impact on stellar nucleosynthesis

Author

P. Mutti, A. Brusegan, A. Noriega, H. Beer, R. Galleano, and F. Corvi

Subjects
Nuclear physics, Nuclear reaction, Neutron capture, Stellar nucleosynthesis, Chemistry, Nucleosynthesis, Neutron flux, Isotopes of krypton, Nuclear cross section, s-process
Abstract

The Krypton isotopes lie in one of the most sensitive, complicated and, therefore, interesting region of the s-process nucleosynthesis. This mass region, in fact, receives substantial contribution from both the weak and the main component of the s-process. In addition to that, the branching in the s-process path at 85Kr can deliver important information on the neutron flux. The total cross section of 84Kr and the capture cross section of 86Kr have been measured and the MAC cross sections calculated with the aim to reduce the uncertainties in the s-process models due to nuclear parameters.

Published
2000

42. Resonance neutron capture studies

Author

P. Mutti, H. Postma, L. Zanini, H. Beer, F. Corvi, and K. Athanassopulos

Subjects
Nuclear physics, Neutron capture, Isotope, Nucleosynthesis, Chemistry, Astrophysics::High Energy Astrophysical Phenomena, Neutron number, Neutron cross section, Neutron, Neutron scattering, Nuclear Experiment, Neutron temperature
Abstract

Neutron capture studies taking place at the newly refurbished GELINA pulsed neutron facility are presented. These investigations are of two types: first, the total neutron capture cross section is measured with high resolution in the keV region for isotopes which are particularly interesting for the study of s-process nucleosynthesis. From the obtained resonance parameters and/or capture areas, one can derive the stellar capture rate as a function of the temperature kT. Results have recently been obtained for the bottlenecks 138Ba and 208Pb, and for the s-only isotope 136Ba. A second type of experiment consists of measuring with Ge-detectors primary and secondary gamma-rays from neutron capture in single resonances in an effort to derive their spins and parities. These values are important for the interpretation of the results of parity-non-conservation measurements performed at LANSCE (LANL) by the TRIPLE collaboration. Results have just been obtained for the isotope 109Ag.

Published
1997

43. New instrumentation for precise (n,γ) measurements at ILL Grenoble

Author

Bastian Märkisch, C. Bernards, T. Rzaca-Urban, M. Jentschel, C Drescher, Ulli Köster, T. Materna, Ch. Fransen, P. Mutti, Gary Simpson, W. Urban, J. Jolie, Institut Laue-Langevin (ILL), ILL, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Spectrometer, 010308 nuclear & particles physics, business.industry, Instrumentation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Neutron radiation, 7. Clean energy, 01 natural sciences, Collimated light, Coincidence, Nuclear physics, Microsecond, Optics, Excited state, 0103 physical sciences, Neutron, 010306 general physics, business, Mathematical Physics
Abstract

An array of eight Ge detectors for coincidence measurements of γ rays from neutron-capture reactions has been constructed at the PF1B cold-neutron facility of the Institut Laue-Langevin. The detectors arranged in one plane every 45° can be used for angular correlation measurements. The neutron collimation line of the setup provides a neutron beam of 12 mm in diameter and the capture flux of about 108/(s × cm2) at the target position, with a negligible neutron halo. With the setup up to 109 γγ and up to 108 triple-γ coincidence events have been collected in a day measurement. Precise energy and efficiency calibrations up to 10 MeV are easily performed with 27Al(n,γ)28Al and 35Cl(n,γ)36Cl reactions. Test measurements have shown that neutron binding energies can be determined with an accuracy down to a few eV and angular correlation coefficients measured with a precision down to a percent level. The triggerless data collected with a digital electronics and acquisition allows to determine half-lives of excited levels in the nano- to microsecond range. The high resolving power of double- and triple-γ time coincidences allows significant improvements of excitation schemes reported in previous (n,γ) works and complements high-resolution γ-energy measurements at the double-crystal Bragg spectrometer GAMS of ILL.

Published
2013

44. γ-ray spectroscopy of fission fragments from the cold-neutron235U induced fission with EXILL

Author

T. Konstantinopoulos, A. Astier, C. Petrache, A. Abudra, R. Bontemps, I. Deloncle, S. Kaim, R. Leguillon, M.-G. Porquet, T. Zerrouki, L. Grente, M.-D. Salsac, M. Zielinska, G. de France, Z. Janas, M. Karny, A. Korgul, M. Ramdhane, G. Gey, G. Simpson, A. Vancraeyenest, A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, W. Urban, G. Duchêne, R. Lozeva, F. Ibrahim, A. Gargano, A. Covello, D. Mengoni, C.A. Ur, M. Sferrazza, B. Melon, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), CSNSM SNO, 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)-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)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), F. Farget, A. Chatillon, H. Faust, G. Fioni, D. Goutte, H. Goutte, 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), 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)-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)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), ILL, and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Fission products, 010308 nuclear & particles physics, Fission, QC1-999, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Neutron radiation, Nuclear reactor, 7. Clean energy, 01 natural sciences, law.invention, Nuclear physics, law, 0103 physical sciences, Neutron, Nuclear Experiment, Spectroscopy, 010303 astronomy & astrophysics
Abstract

Expérience ILL/EXOGAM; International audience; A cold neutron induced fission experiment recently took place at the Institute Laue-Langevin (ILL) in Grenoble. The neutron beam was provided by the nuclear reactor facility at ILL and the detector setup that was used for the -spectroscopy of the fission products consisted mainly of the detectors of the EXOGAM array [1], thereby the name of the campaign is EXILL. The main purpose of our measurement was to investigate the nuclei in the region with N = 50 close to 78Ni as well as the nuclei close to the N = 82 shell closure. In this paper, the motivation of the experiment is described as well as the experimental setup and the status of the ongoing data analysis.

Published
2013

45. The stellar capture rate of 208Pb

Author

H. Beer, F. Corvi, K. Athanassopulos, and P. Mutti

Subjects
Nuclear physics, Nuclear reaction, Physics, Cross section (physics), Neutron capture, Nucleosynthesis, Astrophysics::High Energy Astrophysical Phenomena, Resonance, Neutron, s-process, Stellar evolution
Abstract

High resolution neutron capture measurements of a highly enriched 208Pb sample were carried out at the GELINA pulsed neutron facility and the capture areas of twelve resonances in the range 1–400 keV were determined. From these values the Maxwellian‐averaged cross section 〈σ〉 was calculated vs kT from 5 to 100 keV. After adding the estimated direct capture contribution, our results agree with those of previous activation measurements but are a factor or two lower than the Oak Ridge neutron capture data. The reason for such a discrepancy was singled out.

Published
1995

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