14 results on '"V. Paziy"'
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2. Lifetime measurements in the odd−A nucleus Hf177
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G. Häfner, W. Korten, L. M. Fraile, N. Saed-Samii, A. Esmaylzadeh, Gheorghe Pascovici, Paolo Mutti, J. F. Smith, Zs. Podolyák, W. Urban, Torsten Soldner, Aurelien Blanc, G. S. Simpson, N. Warr, V. Paziy, Ulli Köster, V. Karayonchev, Michael Jentschel, C. A. Ur, C. Townsley, S. Ilieva, Henryk Mach, J. Jolie, A. Vancraeyenest, N. Mǎrginean, L. Knafla, G. Thiamova, Alison Bruce, S. Leoni, J.-M. Régis, S. Lalkovski, P. H. Regan, Petr Alexa, Oliver J. Roberts, and T. Kröll
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Physics ,medicine.anatomical_structure ,Spectrometer ,010308 nuclear & particles physics ,0103 physical sciences ,Rare earth ,Nuclear structure ,medicine ,Atomic physics ,Nanosecond ,010306 general physics ,01 natural sciences ,Nucleus - Abstract
Lifetimes of low- and high-spin states in the odd-A nucleus Hf-177 were measured during the EXILL&FATIMA campaign using a spectrometer equipped with eight HPGe-Clover detectors and 16 fast-timing LaBr3(Ce) detectors. For the determination of lifetimes in the pico- to nanosecond regime, the well-established generalized centroid difference method was used. Lifetimes of the 9/2(-), 9/2(+), 11/2(-), 11/2(+) states were remeasured, the lifetimes of the 13/2(-), 17/2(-), 13/2(+), 15/2(+), and 17/2(+) states were determined for the first time and an upper limit for the 19/2(+) state has been established. From these lifetimes absolute reduced transition probabilities were extracted and compared to particle-rotor-model calculations and quasiparticle-phonon-model calculations showing the importance of including multipole-multipole interactions in the description of odd-A nuclei in the rare earth region.
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- 2020
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3. Low- Z boundary of the N=88 –90 shape phase transition: Ce148 near the critical point
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Tamara Nikšić, Zs. Podolyák, V. Werner, E. Wilson, P. H. Regan, N. Marginean, Petr Alexa, W. Korten, D. Wilmsen, Ulli Köster, Paolo Mutti, S. Lalkovski, C. Bernards, N. Cooper, Torsten Soldner, C. A. Ur, Oliver J. Roberts, Dario Vretenar, Aurelien Blanc, P. Koseoglou, V. Paziy, T. Kröll, Norbert Pietralla, Michael Jentschel, Zena Patel, M. Thürauf, L. M. Fraile, N. Saed-Samii, Alison Bruce, S. Ilieva, W. Urban, Henryk Mach, J. Jolie, G. S. Simpson, R. B. Cakirli, and J.-M. Régis
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Physics ,Phase transition ,010308 nuclear & particles physics ,Fission ,Nuclear structure ,7. Clean energy ,01 natural sciences ,Coincidence ,medicine.anatomical_structure ,13. Climate action ,Critical point (thermodynamics) ,Excited state ,0103 physical sciences ,medicine ,Atomic physics ,010306 general physics ,Spectroscopy ,Nucleus - Abstract
Excited states of the neutron-rich nucleus 148Ce have been populated by neutron-induced fission of 235U and 241Pu samples. Their electromagnetic decays were studied by means of γ-ray coincidence spectroscopy with fast-timing capabilities. Lifetimes of the 2+1 and 4+1 states of 148Ce were obtained and their E2 decay rates deduced. The B4=2 = B(E2; 4+1 → 2+1)=B(E2; 2+1 → 0+1) ratio indicates that 148Ce is a transitional nucleus while the N = 88/90 shape phase transition evolves into a gradual change of nuclear deformation for proton numbers Z < 60.
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- 2020
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4. The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus 133Sb
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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)
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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.
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- 2016
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5. Lifetimes and shape-coexisting states of $^{99}Zr$
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J. F. Smith, N. Saed-Samii, R. Lica, G. S. Simpson, V. Werner, L. M. Fraile, C. Bernards, W. Korten, S. Lalkovski, P. H. Regan, T. Kröll, N. Marginean, A. Vancraeyenest, Torsten Soldner, Paolo Mutti, P. Spagnoletti, V. Paziy, F. Drouet, C. Townsley, Marcus Scheck, Liam Gaffney, Henryk Mach, J. Jolie, G Thiamova, M. Zielińska, J.-M. Régis, C. A. Ur, N. Warr, S. Ilieva, Michael Jentschel, S. Kisyov, W. Urban, Aurelien Blanc, Zs. Podolyák, Ulli Köster, D. Ghita, Alison Bruce, C. Larijarni, D. Bucurescu, V. Vedia, 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, 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, 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), 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), and 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])
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Physics ,010308 nuclear & particles physics ,Fission ,Nuclear structure ,Shell (structure) ,Deformation (meteorology) ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Structure ,01 natural sciences ,medicine.anatomical_structure ,Beamline ,Excited state ,0103 physical sciences ,Quadrupole ,medicine ,Física nuclear ,Nuclear Physics - Experiment ,Atomic physics ,010306 general physics ,Nucleus - Abstract
Lifetimes of intermediate-spin states in two rotational bands of 99Zr have been measured. These states were populated following the neutron-induced fission of 235U at the PF1B beamline of the Institut Laue-Langevin, Grenoble, during the EXILL-FATIMA campaign. The nucleus 99Zr59 exhibits shape coexistence and lies precisely on the border of an abrupt change in ground-state deformation when going from N=58 to N=60, making its study interesting for understanding the mechanisms involved in the rapid onset of deformation here. The B(E2) values extracted for decays in the ν3/2[541] band allow quadrupole deformations of β2=0.34(1) and 0.26(3) to be determined for the 821.6- and 1236.6-keV members, whereas β2=0.32(3) was found for the 850.5-keV member of the ν3/2[411]band. Some of the excited states known in 99Zr have been reasonably described with interacting boson-fermion model (IBFM) calculations. Type-II shell evolution is proposed to play a major role in modifying single-particle energies in 99Zr.
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- 2019
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6. The boundary of the N=90 shape phase transition: 148Ce
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P. Koseoglou, V. Werner, N. Pietralla, S. Ilieva, M. Thürauf, C. Bernards, A. Blanc, A. M. Bruce, R. B. Cakirli, N. Cooper, L. M. Fraile, G. de France, M. Jentschel, J. Jolie, U. Koester, W. Korten, T. Kröll, S. Lalkovski, H. Mach, N. Mărginean, P. Mutti, Z. Patel, V. Paziy, Z. Podolyák, P. H. Regan, J.-M. Régis, O. J. Roberts, N. Saed-Samii, G. S. Simpson, T. Soldner, C. A. Ur, W. Urban, D. Wilmsen, E. Wilson, 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), 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), 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), 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 ), Université Grenoble Alpes (UGA), and 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])
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Physics ,History ,Phase transition ,Spectrometer ,010308 nuclear & particles physics ,Fission ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,01 natural sciences ,Computer Science Applications ,Education ,Semiconductor detector ,Critical point (thermodynamics) ,Picosecond ,0103 physical sciences ,Atomic nucleus ,ddc:530 ,Física nuclear ,Interacting boson model ,Atomic physics ,010306 general physics ,Nuclear Experiment - Abstract
Journal of physics / Conference Series Conference Series 1023, 012022 - (2018). doi:10.1088/1742-6596/1023/1/012022, Published by IOP Publ., Bristol
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- 2018
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7. Experimental study of the lifetime and phase transition in neutron-rich Zr98,100,102
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O. Stezowski, Tomoaki Togashi, S. Ansari, F. Drouet, N. Saed-Samii, G. S. Simpson, E. Wilson, S. Ilieva, C. A. Ur, W. Korten, V. Paziy, M. D. Salsac, C. Townsley, A. Vancraeyenest, L. M. Fraile, Marcus Scheck, Paolo Mutti, Emyr Clement, B. Olaizola, Henryk Mach, J. Jolie, J.-M. Régis, J. F. Smith, V. Vedia, Oliver J. Roberts, M. Zielińska, Raymond J. Carroll, Zs. Podolyák, W. Urban, Takaharu Otsuka, A. Ignatov, S. Lalkovski, P. H. Regan, N. Marginean, T. Soldner, C. Larijani, Alison Bruce, Yusuke Tsunoda, A.-L. Hartig, T. Kröll, Noritaka Shimizu, Aurelien Blanc, Ulli Köster, N. Warr, and Michael Jentschel
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Physics ,Phase transition ,010308 nuclear & particles physics ,Fission ,Context (language use) ,Neutron radiation ,01 natural sciences ,7. Clean energy ,Excited state ,0103 physical sciences ,Neutron ,Atomic physics ,Interacting boson model ,Nuclear Experiment ,010306 general physics ,Line (formation) - Abstract
Rapid shape changes are observed for neutron-rich nuclei with A around 100. In particular, a sudden onset of ground-state deformation is observed in the Zr and Sr isotopic chains at N = 60: Low-lying states in $N\ensuremath{\le}58$ nuclei are nearly spherical, while those with $N\ensuremath{\ge}60$ have a rotational character. Nuclear lifetimes as short as a few picoseconds can be measured using fast-timing techniques with ${\mathrm{LaBr}}_{3}$(Ce) scintillators, yielding a key ingredient in the systematic study of the shape evolution in this region. We used neutron-induced fission of $^{241}\mathrm{Pu}$ and $^{235}\mathrm{U}$ to study lifetimes of excited states in fission fragments in the $A\ensuremath{\sim}100$ region with the EXILL-FATIMA array located at the PF1B cold neutron beam line at the Institut Laue-Langevin. In particular, we applied the generalized centroid difference method to deduce lifetimes of low-lying states for the nuclei $^{98}\mathrm{Zr}$ (N = 58), $^{100}\mathrm{Zr}$, and $^{102}\mathrm{Zr}$ ($N\ensuremath{\ge}60$). The results are discussed in the context of the presumed phase transition in the Zr chain by comparing the experimental transition strengths with the theoretical calculations using the interacting boson model and the Monte Carlo shell model.
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- 2017
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8. Search for the Ga73 ground-state doublet splitting in the β decay of Zn73
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W. B. Walters, R. Lica, G. S. Simpson, P. Hoff, J.-M. Régis, L. M. Fraile, Ani Aprahamian, Z. Dlouhý, W. Kurcewicz, Ulli Köster, Brian Bucher, L. Stroe, V. Vedia, José Antonio Briz, T. Sava, M. Rudigier, R. Mărginean, Henryk Mach, J. Jolie, N. Marginean, C. J. Chiara, V. Paziy, C. Bernards, B. Olaizola, M. Stanoiu, D. Ghiţă, and Ioana Gheorghe
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Physics ,Work (thermodynamics) ,Large Hadron Collider ,010308 nuclear & particles physics ,New energy ,Coulomb excitation ,State (functional analysis) ,01 natural sciences ,Excited state ,0103 physical sciences ,Atomic physics ,010306 general physics ,Ground state ,Spectroscopy - Abstract
The existence of two close-lying nuclear states in ⁷³Ga has recently been experimentally determined: a 1/2⁻ spin-parity for the ground state was measured in a laser spectroscopy experiment, while a J_π = 3/2⁻ level was observed in transfer reactions. This scenario is supported by Coulomb excitation studies, which set a limit for the energy splitting of 0.8 keV. In this work, we report on the study of the excited structure of ⁷³Ga populated in the β decay of ⁷³Zn produced at ISOLDE, CERN. Using β-gated, γ-ray singles, and γ –γ coincidences, we have searched for energy differences to try to delimit the ground-state energy splitting, providing a more stringent energy difference limit. Three new half-lives of excited states in ⁷³Ga have been measured using the fast-timing ;method with LaBr₃(Ce) detectors. From our study, we help clarify the excited structure of ⁷³G and we extend the existing ⁷³Zn decay to ⁷³Ga with 8 new energy levels and 35 γ transitions. We observe a 195-keV transition consistent with a γ ray de-exciting a short-lived state in the β-decay parent ⁷³Zn.
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- 2017
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9. Abrupt shape transition at neutron number N=60 : B(E2) values in Sr94,96,98 from fast γ−γ timing
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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
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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.
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- 2017
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10. Half-life of the15/2+state ofI135: A test ofE2seniority relations
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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
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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.
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- 2017
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11. Measurement of picosecond lifetimes in neutron-rich Xe isotopes
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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)
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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.
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- 2016
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12. Lifetime measurement in neutron-rich A~100 nuclei
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Oliver J. Roberts, L. M. Fraile, W. Korten, Takaharu Otsuka, E. Wilson, N. Warr, O. Stezowski, M. Zielińska, Aurelien Blanc, Ulli Köster, F. Drouet, Tomoaki Togashi, W. Urban, Paolo Mutti, Torsten Soldner, S. Ansari, J.-M. Régis, Michael Jentschel, Yusuke Tsunoda, T. Kröll, N. Saed-Samii, C. A. Ur, S. Ilieva, V. Paziy, Noritaka Shimizu, C. Townsley, Henryk Mach, J. Jolie, G. S. Simpson, A.-L. Hartig, J. F. Smith, M. D. Salsac, A. Vancraeyenest, C. Larijani, Marcus Scheck, Eric Clément, Raymond J. Carroll, A. Ignatov, Alison Bruce, Zs. Podolyák, S. Lalkovski, P. H. Regan, N. Marginean, V. Vedia, B. Olaizola, 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 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)-Université Grenoble Alpes (UGA), 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 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), 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 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), 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), 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
Physics ,010308 nuclear & particles physics ,Fission ,QC1-999 ,SHELL model ,Monte Carlo method ,Nuclear Theory ,Centroid ,Deformation (meteorology) ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,01 natural sciences ,7. Clean energy ,Nuclear physics ,Excited state ,0103 physical sciences ,Neutron ,010306 general physics ,Nuclear Experiment - Abstract
Lifetimes of excited states of the 98;100;102Zr nuclei were measured by using the Generalized Centroid Difference Method. The nuclei of interest were populated via neutron-induced fission of 241Pu and 235U during the EXILL-FATIMA campaign. The obtained lifetimes were used to calculate the B(E2) transition strengths and β deformation parameters which were then compared with the recent theoretical predictions obtained with Monte Carlo Shell Model.
- Published
- 2018
- Full Text
- View/download PDF
13. The γ-γ fast-timing technique and the EXILL&FATIMA campaign
- Author
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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
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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
- Full Text
- View/download PDF
14. B(E2;21+→01+)value inKr90
- Author
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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, T. Kröll, A.-L. Hartig, A. Ignatov, S. Ilieva, M. Thürauf, S. Lalkovski, D. Ivanova, S. Kisyov, W. Korten, M.-D. Salsac, M. Zielińska, N. Mărginean, D. G. Ghită, R. Lică, C. M. Petrache, A. Astier, and R. Leguillon
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Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,0103 physical sciences ,Atomic physics ,010306 general physics ,01 natural sciences ,Sudden onset - Abstract
A smooth onset of collectivity in ${}^{88,92,94,96}\mathrm{Kr}$ has been determined from reported $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ and $E({2}_{1}^{+})$ values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ value in $^{90}\mathrm{Kr}$, which was produced by cold-neutron-induced fission of ${}^{235}\mathrm{U}$. The lifetime of the ${2}_{1}^{+}$ state in $^{90}\mathrm{Kr}$ was measured via the electronic $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ timing technique using the EXILL and FATIMA spectrometers. Based on the measured mean lifetime of $\ensuremath{\tau}$ = 15(10) ps, the $B(E2;{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ value of $13{}_{\ensuremath{-}5}^{+26}$ W.u. in $^{90}\mathrm{Kr}$ is determined for the first time and the smooth onset of deformation in the even-even Kr isotopes beyond neutron number $N=50$ is confirmed.
- Published
- 2014
- Full Text
- View/download PDF
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