Showing 1–27 of 27 results for author: Camera, F

Statistical properties and photon strength functions of the ${}^{112,114}$Sn isotopes below the neutron separation threshold

Authors: P. -A. Söderström, M. Markova, N. Tsoneva, Y. Xu, A. Kuşoğlu, S. Aogaki, D. L. Balabanski, S. R. Ban, R. Borcea, M. Brezeanu, F. Camera, M. Ciemała, Gh. Ciocan, C. Clisu, C. Costache, F. C. L. Crespi, M. Cuciuc, A. Dhal, I. Dinescu, N. M. Florea, A. Giaz, M. Kmiecik, V. Lelasseux, R. Lica, N. M. Mărginean , et al. (19 additional authors not shown)

Abstract: Here, we report on the measurements of the $γ$-ray strength functions and nuclear level densities of ${}^{112,114}$Sn performed for the first time at the 9~MV Tandem accelerator facilities at IFIN-HH using the Oslo method. We extract thermodynamic properties and gross and fine properties of the pygmy dipole resonance for systematic comparison in the chain of Sn isotopes. The results are compared w… ▽ More Here, we report on the measurements of the $γ$-ray strength functions and nuclear level densities of ${}^{112,114}$Sn performed for the first time at the 9~MV Tandem accelerator facilities at IFIN-HH using the Oslo method. We extract thermodynamic properties and gross and fine properties of the pygmy dipole resonance for systematic comparison in the chain of Sn isotopes. The results are compared with microscopic models implemented in the TALYS reaction code and the fully microscopic quasiparticle-phonon model for the underlying nuclear structure of the dipole strength in ${}^{112,114}$Sn. The quasiparticle-phonon model results show the importance of complex configurations to the low-energy dipole response in the pygmy dipole resonance energy region. The experimental data are further included in the cross-section and reaction rate calculations for the $(\mathrm{n},γ)$ reaction of the $p$-process nuclei ${}^{112,114}$Sn showing a significant increase in reaction rates at high temperatures compared to existing nuclear databases. △ Less

Submitted 4 February, 2025; v1 submitted 9 October, 2024; originally announced October 2024.

Comments: 21 pages, 17 figures

Spherical-oblate shape coexistence in $^{94}$Zr from a model-independent analysis

Authors: N. Marchini, M. Rocchini, M. Zielinska, A. Nannini, D. T. Doherty, N. Gavrielov, P. E. Garrett, K. Hadynska-Klek, A. Goasduff, D. Testov, S. D. Bakes, D. Bazzacco, G. Benzoni, T. Berry, D. Brugnara, F. Camera, W. N. Catford, M. Chiari, F. Galtarossa, N. Gelli, A. Gottardo, A. Gozzelino, A. Illana, J. Keatings, D. Mengoni , et al. (11 additional authors not shown)

Abstract: Low-lying states of $^{94}$Zr were investigated via low-energy multi-step Coulomb excitation. From the measured $γ$-ray yields, 13 reduced transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the $2_{1,2}^+$ states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the $0_{1,2}^+$ states includin… ▽ More Low-lying states of $^{94}$Zr were investigated via low-energy multi-step Coulomb excitation. From the measured $γ$-ray yields, 13 reduced transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the $2_{1,2}^+$ states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the $0_{1,2}^+$ states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of $^{94}$Zr possesses a rather diffuse shape associated with a spherical configuration, while the $0_2^+$ state is oblate and more strongly deformed. The observed features of shape coexistence in $^{94}$Zr are in agreement with Monte-Carlo shell-model predictions, and the present results are vital to refine the IBM-CM description of the Zr isotopes around $A\approx 100$ in terms of an intertwined quantum phase transition. △ Less

Submitted 13 August, 2024; originally announced August 2024.

Comments: 6 pages, 3 figures

PANDORA project: photo-nuclear reactions below $A=60$

Authors: A. Tamii, L. Pellegri, P. -A. Söderström, D. Allard, S. Goriely, T. Inakura, E. Khan, E. Kido, M. Kimura, E. Litvinova, S. Nagataki, P. von Neumann-Cosel, N. Pietralla, N. Shimizu, N. Tsoneva, Y. Utsuno, S. Adachi, P. Adsley, A. Bahini, D. Balabanski, B. Baret, J. A. C. Bekker, S. D. Binda, E. Boicu, A. Bracco , et al. (56 additional authors not shown)

Abstract: Photo-nuclear reactions of light nuclei below a mass of $A=60$ are studied experimentally and theoretically by the PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project. Two experimental methods, virtual-photon excitation by proton scattering and real-photo absorption by a high-brilliance gamma-ray beam produced by laser Compton scattering, will be applie… ▽ More Photo-nuclear reactions of light nuclei below a mass of $A=60$ are studied experimentally and theoretically by the PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project. Two experimental methods, virtual-photon excitation by proton scattering and real-photo absorption by a high-brilliance gamma-ray beam produced by laser Compton scattering, will be applied to measure the photo-absorption cross sections and the decay branching ratio of each decay channel as a function of the photon energy. Several nuclear models, e.g. anti-symmetrized molecular dynamics, mean-field type models, a large-scale shell model, and ab initio models, will be employed to predict the photo-nuclear reactions. The uncertainty in the model predictions will be evaluated from the discrepancies between the model predictions and the experimental data. The data and the predictions will be implemented in a general reaction calculation code TALYS . The results will be applied to the simulation of the photo-disintegration process of ultra-high-energy cosmic rays in inter-galactic propagation. △ Less

Submitted 18 November, 2022; v1 submitted 7 November, 2022; originally announced November 2022.

Complete set of bound negative-parity states in the neutron-rich 18N nucleus

Authors: S. Ziliani, M. Ciemała, F. C. L. Crespi, S. Leoni, B. Fornal, T. Suzuki, T. Otsuka, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Orynczak, E. Clément, S. Coelli, O. Dorvaux, S. Erturk, G. De France, C. Fransen , et al. (32 additional authors not shown)

Abstract: High-resolution gamma-ray spectroscopy of 18N is performed with the Advanced GAmma Tracking Array AGATA, following deep-inelastic processes induced by an 18O beam on a 181Ta target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in 18N below the neutron threshold. Spin and parities are proposed for all located st… ▽ More High-resolution gamma-ray spectroscopy of 18N is performed with the Advanced GAmma Tracking Array AGATA, following deep-inelastic processes induced by an 18O beam on a 181Ta target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in 18N below the neutron threshold. Spin and parities are proposed for all located states on the basis of decay branchings and comparison with large-scale shell-model calculations performed in the p-sd space, with the YSOX interaction. Of particular interest is the location of the 0^-_1 and 1^-_2 excitations, which provide strong constrains for cross-shell p-sd matrix elements based on realistic interactions, and help to simultaneously reproduce the ground and first-excited states in 16N and 18N, for the first time. Understanding the 18N structure may also have significant impact on neutron-capture cross-section calculations in r-process modeling including light neutron-rich nuclei. △ Less

Submitted 18 April, 2021; v1 submitted 25 March, 2021; originally announced March 2021.

Journal ref: Phys. Rev. C 104, L041301 (2021)

Accessing tens-to-hundreds femtoseconds nuclear state lifetimes with low-energy binary heavy-ion reactions

Authors: M. Ciemala, S. Ziliani, F. C. L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Orynczak, E. Clement, S. Coelli, O. Dorvaux, S. Erturk, G. De France, C. Fransen, A. Goldkuhle, J. Grebosz , et al. (30 additional authors not shown)

Abstract: A novel Monte Carlo technique has been developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range. The method is applied to low-energy heavy-ion binary reactions populating nuclei with complex velocity distributions. Its relevance is demonstrated in connection with the $^{18}$O(7.0 MeV/u) + $^{181}$Ta experiment, performed at GANIL with the AGATA+VAMOS+PARIS setu… ▽ More A novel Monte Carlo technique has been developed to determine lifetimes of excited states in the tens-to-hundreds femtoseconds range. The method is applied to low-energy heavy-ion binary reactions populating nuclei with complex velocity distributions. Its relevance is demonstrated in connection with the $^{18}$O(7.0 MeV/u) + $^{181}$Ta experiment, performed at GANIL with the AGATA+VAMOS+PARIS setup, to study neutron-rich O, C, N, ... nuclei. Excited states in $^{17}$O and $^{19}$O, with known lifetimes, are used to validate the method over the $\sim$20-400 fs lifetime-sensitivity range. Emphasis is given to the unprecedented position resolution provided by $γ$-tracking arrays, which turns out to be essential for reaching the required accuracy in Doppler-shift correction, at the basis of the detailed analysis of $γ$-ray lineshape and resulting state lifetime determination. The technique is anticipated to be an important tool for lifetime investigations in exotic neutron-rich nuclei, produced with intense ISOL-type beams. △ Less

Submitted 9 December, 2020; originally announced December 2020.

Manifestation of the Berry phase in the atomic nucleus $^{213}$Pb

Authors: J. J. Valiente-Dobón, A. Gottardo, G. Benzoni, A. Gadea, S. Lunardi, A. Algora, G. de Angelis, D. Bazzacco, J. Benlliure, P. Boutachkov, A. Bracco, A. M. Bruce, F. Camera, E. Casarejos, M. L. Cortés, F. C. L. Crespi, A. Corsi, C. Domingo-Pardo, M. Doncel, T. Engert, H. Geissel, J. Gerl, N. Goel, M. Górska, J. Grebosz , et al. (35 additional authors not shown)

Abstract: The neutron-rich $^{213}$Pb isotope was produced in the fragmentation of a primary 1 GeV $A$ $^{238}$U beam, separated in FRS in mass and atomic number, and then implanted for isomer decay $γ$-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in $^{213}$Pb are characterized by the seniority quantum number that counts the n… ▽ More The neutron-rich $^{213}$Pb isotope was produced in the fragmentation of a primary 1 GeV $A$ $^{238}$U beam, separated in FRS in mass and atomic number, and then implanted for isomer decay $γ$-ray spectroscopy with the RISING setup at GSI. A newly observed isomer and its measured decay properties indicate that states in $^{213}$Pb are characterized by the seniority quantum number that counts the nucleons not in pairs coupled to angular momentum $J=0$. The conservation of seniority is a consequence of the Berry phase associated with particle-hole conjugation, which becomes gauge invariant and therefore observable in semi-magic nuclei where nucleons half-fill the valence shell. The $γ$-ray spectroscopic observables in $^{213}$Pb are thus found to be driven by two mechanisms, particle-hole conjugation and seniority conservation, which are intertwined through the Berry phase. △ Less

Submitted 28 October, 2020; originally announced October 2020.

Testing ab initio nuclear structure in neutron-rich nuclei: lifetime measurements of second 2+ states in 16C and 20O

Authors: M. Ciemala, S. Ziliani, F. C. L. Crespi, S. Leoni, B. Fornal, A. Maj, P. Bednarczyk, G. Benzoni, A. Bracco, C. Boiano, S. Bottoni, S. Brambilla, M. Bast, M. Beckers, T. Braunroth, F. Camera, N. Cieplicka-Orynczak, E. Clement, S. Coelli, O. Dorvaux, S. Erturk, G. de France, C. Fransen, A. Goldkuhle, J. Grebosz , et al. (69 additional authors not shown)

Abstract: To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich 20O, tau(2+_2 ) = 150(+80-30) fs, and an estimate for the lifetime of the second 2+ state in 16C have been obtained, for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds femtosec… ▽ More To test the predictive power of ab initio nuclear structure theory, the lifetime of the second 2+ state in neutron-rich 20O, tau(2+_2 ) = 150(+80-30) fs, and an estimate for the lifetime of the second 2+ state in 16C have been obtained, for the first time. The results were achieved via a novel Monte Carlo technique that allowed us to measure nuclear state lifetimes in the tens-to-hundreds femtoseconds range, by analyzing the Doppler-shifted gamma-transition line shapes of products of low-energy transfer and deep-inelastic processes in the reaction 18O (7.0 MeV/u) + 181Ta. The requested sensitivity could only be reached owing to the excellent performances of the AGATA gamma-tracking array, coupled to the PARIS scintillator array and to the VAMOS++ magnetic spectrometer. The experimental lifetimes agree with predictions of ab initio calculations using two- and three-nucleon interactions, obtained with the valence-space in-medium similarity renormalization group for 20O, and with the no-core shell model for 16C. The present measurement shows the power of electromagnetic observables, determined with high-precision gamma spectroscopy, to assess the quality of first-principles nuclear structure calculations, complementing common benchmarks based on nuclear energies. The proposed experimental approach will be essential for short lifetimes measurements in unexplored regions of the nuclear chart, including r-process nuclei, when intense ISOL-type beams become available. △ Less

Submitted 12 February, 2020; originally announced February 2020.

Fast Neutron Detection Efficiency of 6Li and 7Li Enriched CLYC Scintillators using an Am-Be source

Authors: N. Blasi, S. Brambilla, F. Camera, S. Ceruti, A. Giaz, L. Gini, F. Groppi, S. Manenti, A. Mentana, B. Million, S. Riboldi

Abstract: The fast neutrons produced by a calibrated 241Am-Be source were detected by two different Cs2LiYCl6:Ce (CLYC) scintillator detectors. The two cylindrical crystals (1"x1" in size) were enriched with more than 99% of 7Li (C7LYC) and with about 95% of 6Li (C6LYC), respectively. Both crystals can detect fast neutrons whereas only C6LYC can also detect thermal neutrons, due to the presence of 6Li. The… ▽ More The fast neutrons produced by a calibrated 241Am-Be source were detected by two different Cs2LiYCl6:Ce (CLYC) scintillator detectors. The two cylindrical crystals (1"x1" in size) were enriched with more than 99% of 7Li (C7LYC) and with about 95% of 6Li (C6LYC), respectively. Both crystals can detect fast neutrons whereas only C6LYC can also detect thermal neutrons, due to the presence of 6Li. The measurement was performed at the L.A.S.A. Laboratory of INFN and University of Milano (Italy). To identify the neutron events, the Pulse-Shape-Discrimination technique was used. A value for the detection efficiency of the 241Am-Be emitted neutrons, with energy up to 10 MeV, was deduced. △ Less

Submitted 27 July, 2018; originally announced July 2018.

Is Seniority a Partial Dynamic Symmetry in the First $νg_{9/2}$ Shell?

Authors: A. I. Morales, G. Benzoni, H. Watanabe, G. de Angelis, S. Nishimura, L. Coraggio, A. Gargano, N. Itaco, T. Otsuka, Y. Tsunoda, P. Van Isacker, F. Browne, R. Daido, P. Doornenbal, Y. Fang, G. Lorusso, Z. Patel, S. Rice, L. Sinclair, P. -A. Söderström, T. Sumikama, J. Wu, Z. Y. Xu, A. Yagi, R. Yokoyama , et al. (38 additional authors not shown)

Abstract: The low-lying structures of the midshell $νg_{9/2}$ Ni isotopes $^{72}$Ni and $^{74}$Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following $β$ decay of the mother nuclei $^{72}$Co and $^{74}$Co. As a result, we provide a complete picture in terms of the seniority scheme up to the fi… ▽ More The low-lying structures of the midshell $νg_{9/2}$ Ni isotopes $^{72}$Ni and $^{74}$Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following $β$ decay of the mother nuclei $^{72}$Co and $^{74}$Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first $(8^+)$ levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron $g_{9/2}$ shell. We find that the disappearance of the seniority isomerism in the $(8^+_1)$ states can be explained by a lowering of the seniority-four $(6^+)$ levels as predicted years ago. For $^{74}$Ni, the internal de-excitation pattern of the newly observed $(6^+_2)$ state supports a restoration of the normal seniority ordering up to spin $J=4$. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near $^{78}$Ni. △ Less

Submitted 2 May, 2018; v1 submitted 30 October, 2017; originally announced October 2017.

Low-energy enhancement and fluctuations of $γ$-ray strength functions in $^{56,57}$Fe: test of the Brink-Axel hypothesis

Authors: A. C. Larsen, M. Guttormsen, N. Blasi, A. Bracco, F. Camera, L. Crespo Campo, T. K. Eriksen, A. Görgen, T. W. Hagen, V. W. Ingeberg, B. V. Kheswa, S. Leoni, J. E. Midtbø, B. Million, H. T. Nyhus, T. Renstrøm, S. J. Rose, I. E. Ruud, S. Siem, T. G. Tornyi, G. M. Tveten, A. V. Voinov, M. Wiedeking, F. Zeiser

Abstract: Nuclear level densities and $γ$-ray strength functions of $^{56,57}$Fe have been extracted from proton-$γ$ coincidences. A low-energy enhancement in the $γ$-ray strength functions up to a factor of 30 over common theoretical E1 models is confirmed. Angular distributions of the low-energy enhancement in $^{57}$Fe indicate its dipole nature, in agreement with findings for $^{56}$Fe. The high statist… ▽ More Nuclear level densities and $γ$-ray strength functions of $^{56,57}$Fe have been extracted from proton-$γ$ coincidences. A low-energy enhancement in the $γ$-ray strength functions up to a factor of 30 over common theoretical E1 models is confirmed. Angular distributions of the low-energy enhancement in $^{57}$Fe indicate its dipole nature, in agreement with findings for $^{56}$Fe. The high statistics and the excellent energy resolution of the large-volume LaBr$_{3}$(Ce) detectors allowed for a thorough analysis of $γ$ strength as function of excitation energy. Taking into account the presence of strong Porter-Thomas fluctuations, there is no indication of any significant excitation-energy dependence in the $γ$-ray strength function, in support of the generalized Brink-Axel hypothesis. △ Less

Submitted 3 March, 2017; v1 submitted 13 December, 2016; originally announced December 2016.

Comments: 24 pages, 17 figures, accepted for publication in J. Phys. G: Nucl. Phys; Special Issue

Journal ref: J. Phys. G: Nucl. Part. Phys. 44 (2017) 064005

Charged particle decay of hot and rotating $^{88}$Mo nuclei in fusion-evaporation reactions

Authors: S. Valdré, S. Piantelli, G. Casini, S. Barlini, S. Carboni, M. Ciemała, M. Kmiecik, A. Maj, K. Mazurek, M. Cinausero, F. Gramegna, V. L. Kravchuk, L. Morelli, T. Marchi, G. Baiocco, L. Bardelli, P. Bednarczyk, G. Benzoni, M. Bini, N. Blasi, A. Bracco, S. Brambilla, M. Bruno, F. Camera, A. Chbihi , et al. (26 additional authors not shown)

Abstract: A study of fusion-evaporation and (partly) fusion-fission channels for the $^{88}$Mo compound nucleus, produced at different excitation energies in the reaction $^{48}$Ti + $^{40}$Ca at 300, 450 and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged part… ▽ More A study of fusion-evaporation and (partly) fusion-fission channels for the $^{88}$Mo compound nucleus, produced at different excitation energies in the reaction $^{48}$Ti + $^{40}$Ca at 300, 450 and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged particles have been compared with the prediction of the statistical model in its implementation in the Gemini++ code, well suited even for high spin systems, in order to tune the main model parameters in a mass region not abundantly covered by exclusive experimental data. Multiplicities for light charged particles emitted in fusion evaporation events are also presented. Some discrepancies with respect to the prediction of the statistical model have been found for forward emitted $α$-particles; they may be due both to pre-equilibrium emission and to reaction channels (such as Deep Inelastic Collisions, QuasiFission/QuasiFusion) different from the compound nucleus formation. △ Less

Submitted 10 September, 2015; originally announced September 2015.

Comments: 14 pages, 14 figures

Journal ref: Phys. Rev. C 93, 034617 (2016)

Evidence for dipole nature of the low-energy $γ$ enhancement in $^{56}$Fe

Authors: A. C. Larsen, N. Blasi, A. Bracco, F. Camera, T. K. Eriksen, A. Görgen, M. Guttormsen, T. W. Hagen, S. Leoni, B. Million, H. T. Nyhus, T. Renstrøm, S. J. Rose, I. E. Ruud, S. Siem, T. Tornyi, G. M. Tveten, A. V. Voinov, M. Wiedeking

Abstract: The $γ$-ray strength function of $^{56}$Fe has been measured from proton-$γ$ coincidences for excitation energies up to $\approx 11$ MeV. The low-energy enhancement in the $γ$-ray strength function, which was first discovered in the ($^3$He,$αγ$)$^{56}$Fe reaction, is confirmed with the ($p,p^\primeγ$)$^{56}$Fe experiment reported here. Angular distributions of the $γ$ rays give for the first time… ▽ More The $γ$-ray strength function of $^{56}$Fe has been measured from proton-$γ$ coincidences for excitation energies up to $\approx 11$ MeV. The low-energy enhancement in the $γ$-ray strength function, which was first discovered in the ($^3$He,$αγ$)$^{56}$Fe reaction, is confirmed with the ($p,p^\primeγ$)$^{56}$Fe experiment reported here. Angular distributions of the $γ$ rays give for the first time evidence that the enhancement is dominated by dipole transitions. △ Less

Submitted 11 March, 2014; v1 submitted 26 October, 2013; originally announced October 2013.

Comments: 5 pages, 4 figures. Version accepted for publication in Phys. Rev. Letters

Journal ref: Phys. Rev. Lett. 111, 242504 (2013)

Nuclear astrophysics with radioactive ions at FAIR

Authors: R. Reifarth, S. Altstadt, K. Göbel, T. Heftrich, M. Heil, A. Koloczek, C. Langer, R. Plag, M. Pohl, K. Sonnabend, M. Weigand, T. Adachi, F. Aksouh, J. Al-Khalili, M. AlGarawi, S. AlGhamdi, G. Alkhazov, N. Alkhomashi, H. Alvarez-Pol, R. Alvarez-Rodriguez, V. Andreev, B. Andrei, L. Atar, T. Aumann, V. Avdeichikov , et al. (295 additional authors not shown)

Abstract: The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses t… ▽ More The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes. △ Less

Submitted 6 October, 2013; originally announced October 2013.

Comments: Invited Talk given at the Conference Nuclear Physice in Astrophysics VI (NPA6), Lisbon, Portugal, May 19-24 2013. To appear in the NPA6 Proceedings in Journal of Physics: Conference Series (JPCS)

Journal ref: Journal of Physics: Conference Series 665 (2016) 012044

Pre-equilibrium α-particle emission as a probe to study α-clustering in nuclei

Authors: O. V. Fotina, S. A. Goncharov, D. O. Eremenko, S. Yu. Platonov, O. A. Yuminov, V. L. Kravchuk, F. Gramegna, T. Marchi, M. Cinausero, M. D'Agostino, M. Bruno, G. Baiocco, L. Morelli, M. Degerlier, G. Casini, S. Barlini, S. Valdrè, S. Piantelli, G. Pasquali, A. Bracco, F. Camera, O. Wieland, G. Benzoni, N. Blasi, A. Giaz , et al. (2 additional authors not shown)

Abstract: A theoretical approach was developed to describe secondary particle emission in heavy ion collisions, with special regards to pre-equilibrium α-particle production. Griffin's model of non-equilibrium processes is used to account for the first stage of the compound system formation, while a Monte Carlo statistical approach was used to describe the further decay from a hot source at thermal equilibr… ▽ More A theoretical approach was developed to describe secondary particle emission in heavy ion collisions, with special regards to pre-equilibrium α-particle production. Griffin's model of non-equilibrium processes is used to account for the first stage of the compound system formation, while a Monte Carlo statistical approach was used to describe the further decay from a hot source at thermal equilibrium. The probabilities of neutron, proton and α-particle emission have been evaluated for both the equilibrium and pre-equilibrium stages of the process. Fission and γ-ray emission competition were also considered after equilibration. Effects due the possible cluster structure of the projectile which has been excited during the collisions have been experimentally evidenced studying the double differential cross sections of p and α-particles emitted in the E=250MeV 16O +116Sn reaction. Calculations within the present model with different clusterization probabilities have been compared to the experimental data. △ Less

Submitted 2 October, 2013; originally announced October 2013.

Comments: 4 pages, 6 figures

Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei

Authors: S. Valdre', S. Barlini, G. Casini, G. Pasquali, S. Piantelli, S. Carboni, M. Cinausero, F. Gramegna, T. Marchi, G. Baiocco, L. Bardelli, G. Benzoni, M. Bini, N. Blasi, A. Bracco, S. Brambilla, M. Bruno, F. Camera, A. Corsi, F. Crespi, M. D Agostino, M. Degerlier, V. L. Kravchuk, S. Leoni, B. Million , et al. (19 additional authors not shown)

Abstract: The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A about 100) models predict that shape transitions can occur at high spin val… ▽ More The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A about 100) models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible preequilibrium emissions from 300 to 600 MeV bombarding energy. △ Less

Submitted 9 September, 2013; originally announced September 2013.

Comments: 4 pages, 3 figures, Contribution to conference proceedings of the 25th International Nuclear Physics Conference (INPC 2013) Journal-ref: 25th International Nuclear Physics Conference (INPC 2013), Firenze : Italy (2013)

Identification and rejection of scattered neutrons in AGATA

Authors: M. Şenyiğit, A. Ataç, S. Akkoyun, A. Kaşkaş, D. Bazzacco, J. Nyberg, F. Recchia, S. Brambilla, F. Camera, F. C. L. Crespi, E. Farnea, A. Giaz, A. Gottardo, R. Kempley, J. Ljungvall, D. Mengoni, C. Michelagnoli, B. Million, M. Palacz, L. Pellegri, S. Riboldi, E. Şahin, P. A. Söderström, J. J. Valiente Dobon, the AGATA collaboration

Abstract: Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study… ▽ More Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study the interaction of neutrons in the segmented high-purity germanium detectors of AGATA and to investigate the possibility to discriminate neutrons and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were used for a time-of-flight measurement, which gave an independent discrimination of neutrons and gamma rays and which was used to optimise the gamma-ray tracking-based neutron rejection methods. It was found that standard gamma-ray tracking, without any additional neutron rejection features, eliminates effectively most of the interaction points due to recoiling Ge nuclei after elastic scattering of neutrons. Standard tracking rejects also a significant amount of the events due to inelastic scattering of neutrons in the germanium crystals. Further enhancements of the neutron rejection was obtained by setting conditions on the following quantities, which were evaluated for each event by the tracking algorithm: energy of the first and second interaction point, difference in the calculated incoming direction of the gamma ray, figure-of-merit value. The experimental results of tracking with neutron rejection agree rather well with Geant4 simulations. △ Less

Submitted 12 June, 2013; originally announced June 2013.

Response of AGATA Segmented HPGe Detectors to Gamma Rays up to 15.1 MeV

Authors: F. C. L. Crespi, R. Avigo, F. Camera, S. Akkoyun, A. Atac, D. Bazzacco, M. Bellato, G. Benzoni, N. Blasi, D. Bortolato, S. Bottoni, A. Bracco, S. Brambilla, B. Bruyneel, S. Cerutia, M. Ciemala, S. Coelli, J. Eberth, C. Fanin, E. Farnea, A. Gadea, A. Giaz, A. Gottardo, H. Hess, M. Kmiecik , et al. (16 additional authors not shown)

Abstract: The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,ng)12C at Ebeam = 19.1 MeV, while gamma-rays between 2 to 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear with… ▽ More The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(11B,ng)12C at Ebeam = 19.1 MeV, while gamma-rays between 2 to 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%. Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation following neutron capture by Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape Analysis, is discussed. △ Less

Submitted 6 September, 2012; originally announced September 2012.

Comments: 10 pages, 11 figures

MSC Class: 81V35

Neutron-skin thickness from the study of the anti-analog giant dipole resonance

Authors: A. Krasznahorkay, L. Stuhl, M. Csatlós, A. Algora, J. Gulyás, J. Timár, N. Paar, D. Vretenar, K. Boretzky, M. Heil, Yu. A. Litvinov, D. Rossi, C. Scheidenberger, H. Simon, H. Weick, A. Bracco, S. Brambilla, N. Blasi, F. Camera, A. Giaz, B. Million, L. Pellegri, S. Riboldi, O. Wieland, S. Altstadt , et al. (35 additional authors not shown)

Abstract: The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\DeltaR_(pn)). By comp… ▽ More The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\DeltaR_(pn)). By comparing the theoretical results with the measured one, the \DeltaR_(pn) value for 124Sn was deduced to be 0.175 \pm 0.048 fm, which agrees well with the previous results. The energy of the AGDR measured previously for ^(208)Pb was also used to determine the \DeltaR_(pn) for ^(208)Pb. In this way a very precise \DeltaR_(pn) = 0.181 \pm 0.031 neutron-skin thickness has been obtained for 208Pb. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes. △ Less

Submitted 20 June, 2012; v1 submitted 10 May, 2012; originally announced May 2012.

Comments: 5 pages, 3 figures

Constraints on the symmetry energy and neutron skins from experiments and theory

Authors: M. B. Tsang, J. R. Stone, F. Camera, P. Danielewicz, S. Gandolfi, K. Hebeler, C. J. Horowitz, Jenny Lee, W. G. Lynch, Z. Kohley, R. Lemmon, P. Moller, T. Murakami, S. Riordan, X. Roca-Maza, F. Sammarruca, A. W. Steiner, I. Vidaña, S. J. Yennello

Abstract: The symmetry energy contribution to the nuclear Equation of State (EoS) impacts various phenomena in nuclear astrophysics, nuclear structure, and nuclear reactions. Its determination is a key objective of contemporary nuclear physics with consequences for the understanding of dense matter within neutron stars. We examine the results of laboratory experiments that have provided initial constraints… ▽ More The symmetry energy contribution to the nuclear Equation of State (EoS) impacts various phenomena in nuclear astrophysics, nuclear structure, and nuclear reactions. Its determination is a key objective of contemporary nuclear physics with consequences for the understanding of dense matter within neutron stars. We examine the results of laboratory experiments that have provided initial constraints on the nuclear symmetry energy and its density dependence at and somewhat below normal nuclear matter density. Some of these constraints have been derived from properties of nuclei. Others have been derived from the nuclear response to electroweak and hadronic probes. We also examine the most frequently used theoretical models that predict the symmetry energy and its slope. By comparing existing constraints on the symmetry pressure to theories, we demonstrate how the contribution of the three-body force, an essential ingredient in neutron matter models, can be determined. △ Less

Submitted 2 April, 2012; originally announced April 2012.

Comments: 28 pages, 4 figures

AGATA - Advanced Gamma Tracking Array

Authors: S. Akkoyun, A. Algora, B. Alikhani, F. Ameil, G. de Angelis, L. Arnold, A. Astier, A. Ataç, Y. Aubert, C. Aufranc, A. Austin, S. Aydin, F. Azaiez, S. Badoer, D. L. Balabanski, D. Barrientos, G. Baulieu, R. Baumann, D. Bazzacco, F. A. Beck, T. Beck, P. Bednarczyk, M. Bellato, M. A. Bentley, G. Benzoni , et al. (329 additional authors not shown)

Abstract: The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the… ▽ More The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realization of gamma-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly-segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterization of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximize its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. △ Less

Submitted 17 September, 2012; v1 submitted 24 November, 2011; originally announced November 2011.

Comments: This version contains a correction of a typing error in the caption of Fig. 2. The DOI to the article published in Nucl. Instr. Meth A was also added

Structural evolution in the neutron-rich nuclei 106Zr and 108Zr

Authors: T. Sumikama, K. Yoshinaga, H. Watanabe, S. Nishimura, Y. Miyashita, K. Yamaguchi, K. Sugimoto, J. Chiba, Z. Li, H. Baba, J. S. Berryman, N. Blasi, A. Bracco, F. Camera, P. Doornenbal, S. Go, T. Hashimoto, S. Hayakawa, C. Hinke, E. Ideguchi, T. Isobe, Y. Ito, D. G. Jenkins, Y. Kawada, N. Kobayashi , et al. (22 additional authors not shown)

Abstract: The low-lying states in 106Zr and 108Zr have been investigated by means of β-γ and isomer spectroscopy at the RI beam factory, respectively. A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2+ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68… ▽ More The low-lying states in 106Zr and 108Zr have been investigated by means of β-γ and isomer spectroscopy at the RI beam factory, respectively. A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2+ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed sub-shell closure at N = 64. The deformed ground state of 108Zr indicates that a spherical sub-shell gap predicted at N = 70 is not large enough to change the ground state of 108Zr to the spherical shape. The possibility of a tetrahedral shape isomer in 108Zr is also discussed. △ Less

Submitted 14 April, 2011; originally announced April 2011.

Comments: 10 pages, 3 figures, Accepted for publication in Phys. Rev. Lett

Journal ref: Phys.Rev.Lett.106:202501,2011

Probing the order-to-chaos region in superdeformed 151Tb and 196Pb nuclei with continuum gamma-transitions

Authors: S. Leoni, G. Benzoni, N. Blasi, A. Bracco, S. Brambilla, F. Camera, A. Corsi, F. C. L. Crespi, P. Mason, B. Million, D. Montanari, M. Pignanelli, E. Vigezzi, O. Wieland, M. Matsuo, Y. R. Shimizu, P. Bednarczyk, M. Castoldi, D. Curien, G. Duchene, B. Herskind, M. Kmiecik, A. Maj, W. Meczynski, J. Robin , et al. (4 additional authors not shown)

Abstract: The gamma-decay associated with the warm rotation of the superdeformed (SD) nuclei 151Tb and 196Pb has been measured with the EUROBALL IV array. Several independent quantities provide a stringent test of the population and decay dynamics in the SD well. A Monte Carlo simulation of the gamma-decay based on microscopic calculations gives remarkable agreement with the data only assuming a large enh… ▽ More The gamma-decay associated with the warm rotation of the superdeformed (SD) nuclei 151Tb and 196Pb has been measured with the EUROBALL IV array. Several independent quantities provide a stringent test of the population and decay dynamics in the SD well. A Monte Carlo simulation of the gamma-decay based on microscopic calculations gives remarkable agreement with the data only assuming a large enhancement of the B(E1) strength at low excitation energy, which may be related to the evidence for octupole vibrations in both mass regions. △ Less

Submitted 30 June, 2008; originally announced June 2008.

Journal ref: Phys.Rev.Lett.101:142502,2008

Strong Deformation Effects in Hot Rotating 46Ti

Authors: M. Kmiecik, A. Maj, M. Brekiesz, K. Mazurek, P. Bednarczyk, J. Grebosz, W. Meczynski, J. Styczen, M. Zieblinski, K. Zuber, P. Papka, C. Beck, D. Curien, F. Haas, V. Rauch, M. Rousseau, J. Dudek, N. Schunck, A. Bracco, F. Camera, G. Benzoni, O. Wieland, B. Herskind, E. Farnea, G. De Angelis

Abstract: Exotic-deformation effects in 46Ti nucleus were investigated by analysing the high-energy gamma-ray and the alpha-particle energy spectra. One of the experiments was performed using the charged-particle multi-detector array ICARE together with a large volume (4"x4") BGO detector. The study focused on simultaneous measurement of light charged particles and gamma-rays in coincidence with the evapo… ▽ More Exotic-deformation effects in 46Ti nucleus were investigated by analysing the high-energy gamma-ray and the alpha-particle energy spectra. One of the experiments was performed using the charged-particle multi-detector array ICARE together with a large volume (4"x4") BGO detector. The study focused on simultaneous measurement of light charged particles and gamma-rays in coincidence with the evaporation residues. The experimental data show a signature of very large deformations of the compound nucleus in the Jacobi transition region at the highest spins. These results are compared to data from previous experiments performed with the HECTOR array coupled to the EUROBALL array, where it was found that the GDR strength function is highly fragmented, strongly indicating a presence of nuclei with very large deformation. △ Less

Submitted 28 December, 2006; originally announced December 2006.

Comments: 10 pages, 6 figures, Proceedings of the Zakopane Conference on Nuclear Physics, to be published in Acta Phys. Pol. B (2007)

Journal ref: ActaPhys.Polon.B38:1437-1446,2007

GDR Feeding of the Highly-Deformed Band in 42Ca

Authors: M. Kmiecik, A. Maj, J. Styczen, P. Bednarczyk, M. Brekiesz, J. Grebosz, M. Lach, W. Meczynski, M. Zieblinski, K. Zuber, A. Bracco, F. Camera, G. Benzoni, B. Million, S. Leoni, O. Wieland, B. Herskind, D. Curien, N. Dubray, J. Dudek, N. Schunck, K. Mazurek

Abstract: The gamma-ray spectra from the decay of the GDR in the compound nucleus reaction 18O+28Si at bombarding energy of 105 MeV have been measured in an experiment using the EUROBALL IV and HECTOR arrays. The obtained experimental GDR strength function is highly fragmented, with a low energy (10 MeV) component, indicating a presence of a large deformation and Coriolis effects. In addition, the prefere… ▽ More The gamma-ray spectra from the decay of the GDR in the compound nucleus reaction 18O+28Si at bombarding energy of 105 MeV have been measured in an experiment using the EUROBALL IV and HECTOR arrays. The obtained experimental GDR strength function is highly fragmented, with a low energy (10 MeV) component, indicating a presence of a large deformation and Coriolis effects. In addition, the preferential feeding of the highly-deformed band in 42Ca by this GDR low energy component is observed. △ Less

Submitted 21 December, 2004; originally announced December 2004.

Comments: 6 pages, 2 figures, Proceedings of the Zakopane2004 Symposium, to be published in Acta Phys. Pol. B36 (2005)

Journal ref: Acta Phys.Polon. B36 (2005) 1169-1174

Evidence for the Jacobi shape transition in hot 46Ti

Authors: A. Maj, M. Kmiecik, A. Bracco, F. Camera, P. Bednarczyk, B. Herskind, S. Brambilla, G. Benzoni, M. Brekiesz, D. Curien, G. DeAngelis, E. Farnea, J. Grebosz, M. Kicinska-Habior, S. Leoni, W. Meczynski, B. Million, D. R. Napoli, J. Nyberg, C. M. Petrache, J. Styczen, O. Wieland, M. Zieblinski, K. Zuber, N. Dubray , et al. (2 additional authors not shown)

Abstract: The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows evidence for the Jacobi shape transiti… ▽ More The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows evidence for the Jacobi shape transition in hot 46Ti. In addition to the previously found broad structure in the GDR lineshape region at 18-27 MeV caused by large deformations, the presence of a low energy component (around 10 MeV), due to the Coriolis splitting in prolate well deformed shape, has been identified for the first time. △ Less

Submitted 24 September, 2003; originally announced September 2003.

Comments: 8 pages, 4 figures, proceedings of the COMEX1 conference, June 2003, Paris; to be published in Nucl. Phys. A

Journal ref: Nucl.Phys. A731 (2004) 319-326

Search for the Jacobi shape transition in light nuclei

Authors: A. Maj, M. Kmiecik, M. Brekiesz, J. Grebosz, W. Meczynski, J. Styczen, M. Zieblinski, K. Zuber, A. Bracco, F. Camera, G. Benzoni, B. Million, N. Blasi, S. Brambilla, S. Leoni, M. Pignanelli, O. Wieland, J. Nyberg, M. Kicinska-Habior, C. M. Petrache, J. Dudek, K. Pomorski

Abstract: The gamma-rays following the reaction 105 MeV 18O + 28Si have been measured using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition. The high-energy gamma-ray spectrum from the GDR decay indicates a presence of large deformations in hot 46Ti nucleus, in agreement with new theoretical calculations based on the Rotating Liquid Drop model. The gamma-rays following the reaction 105 MeV 18O + 28Si have been measured using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition. The high-energy gamma-ray spectrum from the GDR decay indicates a presence of large deformations in hot 46Ti nucleus, in agreement with new theoretical calculations based on the Rotating Liquid Drop model. △ Less

Submitted 7 February, 2003; originally announced February 2003.

Comments: NS2002 Conference. Legnaro, Sptember 2002; to be published in EPJA

Search for the Jacobi Instability in Rapidly Rotating 46Ti* Nuclei

Authors: A. Maj, M. Kmiecik, W. Krolas, J. Styczen, A. Bracco, F. Camera, B. Million, J. J. Gaardhoje, B. Herskind, M. Kicinska-Habior, J. Kownacki, W. E. Ormand

Abstract: The possible existence of Jacobi shape transition in hot 46Ti at high angular momenta was investigated with the Giant Dipole Resonance exclusive experiments. The GDR spectra and the angular distributions are consistent with predictions of the thermal shape fluctuation model indicating elongated nuclear shapes. The possible existence of Jacobi shape transition in hot 46Ti at high angular momenta was investigated with the Giant Dipole Resonance exclusive experiments. The GDR spectra and the angular distributions are consistent with predictions of the thermal shape fluctuation model indicating elongated nuclear shapes. △ Less

Submitted 25 April, 2001; originally announced April 2001.

Comments: Contributed paper at "High Spin Physics 2001", see http://www.fuw.edu.pl/~hs2001/ , to be published in Acta Physica Polonica B

Journal ref: Acta Phys.Polon. B32 (2001) 2433-2439