In this work, the results of measured inclusive double differential cross sections of α particles emitted in the interaction of 14N with 59Co and 93Nb at incident energy of 250 MeV are presented. The experimental data were collected in a wide angular range from 8 to 100 degrees in the laboratory system. The analysis of these data suggests that the measured alpha spectra contains contributions of alpha particles originating from various reaction mechanisms, all of which are important at this high energy. We have also compared our experimental results with the calculations by using a recently developed theoretical model code. This recently developed pre-equilibrium model code is hereby put to a stringent test as to how it performs in case of heavy ion reactions at such high energies.

and Au at Incident energy of 250 MeV Jaimin Acharya*, S. Mukherjee, G. F. Steyn, S.V. Förtsch, F. D. Smit, O. V. Fotina Department of Physics, The M. S. University of Baroda, Vadodara-390020, India iThemba LABS, National Research Foundation, PO box 722, Somerset West, South Africa Physics Department, SINP, M. V. Lomonosov Moscow State University, Moscow, Russia . * email: jaimin.acharya-padra@msubaroda.ac.in

Within a dynamical approach, the average spins of fission fragments originating from the 12C + 235,236U and 13C + 235U complete fusion reactions at c.m. energies in the range of Ec.m. = (55–75) MeV are analyzed as a function of energy. Particular attention is given to the process of formation of initial distributions for the components of the total angular momentum of compound nuclei. It is shown that substantial distinctions in the behavior of average spins of fission fragments for different fusion reaction channels are expected to be observed in the range of subbarrier energies.

The attention to nuclear clustering has been renewed due to the study of weakly bound nuclei at the drip lines. In particular, clustering structural properties in medium-mass systems have been studied by looking at the competition between the evaporation and pre-equilibrium particle emission in central collisions. Although for light nuclei at an excitation energy close to the particle separation value there are experimental evidence of such structure effects, this is still not the case for heavier systems since the determination of pre-formed clusters within nuclear matter is less obvious. Two systems, leading to the same 81Rb* compound nucleus, have been studied at the same beam velocity 16 AMeV: 16O + 65Cu and 19F + 62Ni. The experiment has been performed using the GARFIELD + RCo detection system installed at the Legnaro National Laboratories.Light charged particles energy distributions and multiplicities have been compared with different statistical and dynamical model calculations. From the first comparison between the two systems a difference in the fast α -decay channel has been evidenced, which can be related to the difference in the projectile structure. Recent data analysis results and comparisons with model calculations are presented in this contribution.

The attention to nuclear clustering has been renewed due to the study of weakly bound nuclei at the drip lines. In particular, clustering structural properties in medium-mass systems have been studied by looking at the competition between the evaporation and pre-equilibrium particle emission in central collisions. Although for light nuclei at an excitation energy close to the particle separation value there are experimental evidence of such structure effects, this is still not the case for heavier systems since the determination of pre-formed clusters within nuclear matter is less obvious. Two systems, leading to the same 81 Rb* compound nucleus, have been studied at the same beam velocity 16 AMeV: 16 O + 65 Cu and 19 F + 62 Ni. The experiment has been performed using the GARFIELD + RCo detection system installed at the Legnaro National Laboratories.Light charged particles energy distributions and multiplicities have been compared with different statistical and dynamical model calculations. From the first comparison between the two systems a difference in the fast α -decay channel has been evidenced, which can be related to the difference in the projectile structure. Recent data analysis results and comparisons with model calculations are presented in this contribution.

The pharmacokinetics of the Astatine-211 radiopharmaceutical was investigated after a single injection in male SD (Sprague–Dawley) rats that had normal and iodine-free diets. Twelve groups of SD male rats were examined in the study. The tested drug was intravenously injected into the tail vein of the animals once at a volume of 10 mL/kg and dose of 100 μCi per animal. In the study, the animals were subjected to necropsy at specific time points with retrieval of the organs and tissues for further analysis of the activity of the samples using a well-type scintillation gamma spectrometer. It was found that the 211At absorption by the thyroid in the male rats that had an iodine-free diet was greater than in the rats that had a conventional diet.

A new approach to calculating the mean spins of induced-fission fragments is proposed. This approach, which has the key dynamic aspects of induced fission factored in, was used to analyze experimental data on the angular and energy dependences of mean spins and on the anisotropy of the angular distributions of fission fragments for the 16 O + 232 Th reaction at E cm = 80–150 MeV. The range of relaxation times that provide a consistent description of the experimental data was determined for the degree of freedom associated with the orientation of the symmetry axis of a fissioning nucleus with respect to the total angular momentum.

Nuclear Particle Correlations and Cluster Physics, pp. 507-536 (2017) No AccessCHAPTER 20: USING FAST PROCESSES TO INVESTIGATE CLUSTER STATES AND NUCLEAR CORRELATIONS IN MEDIUM-HEAVY NUCLEI: SPECIFIC TOOLS AND NEW OPPORTUNITIES WITH RADIOACTIVE ION BEAMST. Marchi, F. Gramegna, L. Morelli, S. Barlini, D. Fabris, V.L. Kravchuk, and O.V. FotinaT. MarchiKU Leuven, Dep. of Physics and Astronomy, Instituut voor Kern- en Stralingsfysica, Leuven, Belgium, F. GramegnaINFN Laboratori Nazionali di Legnaro, Legnaro (PD), Italy, L. MorelliUniversity of Bologna, Dep. of Physics and Astronomy and INFN Sezione di Bologna, Bologna, Italy, S. BarliniUniversity of Florence, Dep. of Physics and Astronomy and INFN Sezione di Firenze, Firenze, Italy, D. FabrisINFN Sezione di Padova, Padova, Italy, V.L. KravchukNational Research Centre "Kurchatov Institute", Moscow, Russia, and O.V. FotinaD.V. Skobeltsyn Institue of Nuclear Physics, Moscow State Univ., Russiahttps://doi.org/10.1142/9789813209350_0020Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Clustering effects show up in several ways along the Nuclear Chart. While for light nuclei (A≤40) the existence of clusters has been directly linked to nuclear structure and reaction dynamics observations, this is less the case when moving towards medium-mass systems. Pre-equilibrium emission is a nice example of mechanism capable to fill this gap, linking structure with dynamics and, eventually, to clustering in medium-mass nuclei. For central collisions, cluster pre-formation probabilities can be derived by studying light particle production cross sections and multiplicities. Several theories have been developed in the framework of exciton models to describe pre-equilibrium processes and try to explain how these are influenced by the structure of the reacting nuclei. The forthcoming availability of intense radioactive ion beams will open new challenging scenarios in this field of study, allowing the comparison of new systems where projectiles exhibit extreme neutron to proton ratios, bringing to structural configurations where clusters may show up in a more evident way. FiguresReferencesRelatedDetailsCited By 1Comparative study of four reactions at onset of pre-equilibrium emissionMagda Cicerchia, Fabiana Gramegna, Daniela Fabris, Tommaso Marchi and Marco Cinausero et al.4 December 2019 | EPJ Web of Conferences, Vol. 223 Nuclear Particle Correlations and Cluster PhysicsMetrics History PDF download

A way of calculating the average spins of induced fission fragments is developed, based on the dynamic model of their angular distributions. The range of relaxation times for the degree of freedom associated with the orientation of the axis of symmetry of a fissioning nucleus relative to its total angular momentum is determined by analyzing experimental data on the energy dependences of average spins and the anisotropy of the angular distributions of fission fragments for the 12C, 16O + 232Th reactions at E сm = 55–150 MeV.

Pre-equilibrium emissions affect the production of excited systems in nuclear reactions, thus modifying their properties which enter as input parameters in the comparison with statistical models. In this contribution, we discuss this subject referring to recent results from experiments performed at Legnaro National Laboratories (Italy) with the GARFIELD apparatus complemented with other detectors.

Clustering structural properties in medium-mass systems have been investigated studying the competition between the evaporation and pre-equilibrium particle emission in central collisions. At variance with light nuclei, in the case of heavier nuclei there are no experimental evidences of such structure effects, since the determination of pre-formed clusters within nuclear matter is less obvious.The two systems 16 O + 65 Cu and 19 F + 62 Ni, leading to the same compound system 81 Rb* , have been studied at the same beam velocity (16 AMeV). The experiments have been performed using the GARFIELD + RCo multi-detection system at the Legnaro National Laboratories.Recent results of the data analysis and of the comparison of the experimental data with different statistical and dynamical model calculations are reported in this contribution.

Cluster structure effects in nuclei have been investigated looking to the pre-equilibrium particles emitted in the O-16+Cu-65 and F-19+Ni-62 reactions at the same beam velocity of 16 A MeV which lead to the same Rb-81* compound nucleus. Despite the slight difference in excitation energies, the same fast emission should be expected from the two systems; unless major effects induced by the projectile's cluster structure, which should influence the pre-equilibrium a-particle production during the non-equilibrium stage, are present. The experimental data have been collected with the GARFIELD+RCo apparatus at Laboratori Nazionali di Legnaro. In this contribution we report on the preliminary spectra of light-charged particles, obtained in coincidence with evaporation residues, and their comparison with the results obtained from model calculations.

The study of nuclear states built on clusters bound by valence neutrons in their molecular configurations is a field of large interest. Clustering becomes particularly important at the dripline, where weakly bound systems prevail. For light nuclei, at an excitation energy close to the particle separation value, there are experimental evidences of such structure effects, but this is still not the case for heavier nuclear systems. Several theoretical efforts have been done in the development of pre-formation alpha-clustering models, but there is still a lack of experimental data capable to give a direct feedback. The search of alpha-cluster evidences in medium-mass systems is therefore a new challenge which can give new hints in this field of research.

1 Dipartimento di Fisica, Università “Federico II” di Napoli, Napoli, Italy. 2 INFN Sezione di Padova, Padova, Italy. 3 INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 4 Nevsehir Haci Bektas Veli University, Science & Art Faculty, Physics Department, Nevsehir, Turkey. 5 National Research Center “Kurchatov Institute”, Moscow, Russia. 6 Dipartimento di Fisica e Astronomia dell’Università di Bologna and INFN, Bologna, Italy. 7 Dipartimento di Fisica e Astronomia dell’Università di Firenze and INFN, Firenze, Italy. 8 Skobeltsyn Institute of Nuclear Physics, Moscow state University, Moscow, Russia.

INFN, Sezione di Padova, 35131 Padova, Italy INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro, Italy Nevsehir Haci Bektas Univ., Phys. Dep., Nevsehir, Turkey Skobeltsyn Inst. of Nucl. Phys., Lomonosov Moscow St. Univ., Moscow, Russia National Research Center “Kurchatov Institute”, Moscow, Russia Dip. di Fisica, Univ. di Bologna and INFN Bologna, 40126 Bologna, Italy Dip. di Fisica, Univ. di Firenze and INFN Firenze, 50019 Firenze, Italy Dip. di Fisica, Univ. di Napoli and INFN Napoli, 80138 Napoli, Italy Dip. di Fisica, Univ. di Caserta and INFN Napoli, 80138 Napoli, Italy

The possibility of a self consistent description of a large set of the experimental data concerning the induced fission reactions of heavy nuclei is demonstrated in terms of a theoretical approach to describing the decay of excited heavy nuclei that considers nuclear dissipation and the double-humped structure of the fission barrier. The experimental data on the probability of fission for a large set of nuclei, yields of shape isomers, total fission lifetime, and angular distributions of fission fragments for reactions induced by deuterons and α-particles are analyzed. Theoretical analysis yields new information on the parameters of double-humped fission barriers, magnitude of nuclear viscosity, and relaxation time for K -mode.