Exotic Nuclei

The following sections are included:

• PREFACE
• COMMITTEE
• ORGANIZERS
• CONTENTS

Application of the methods of measuring the radii of the short-lived excited states (Modified diffraction model MDM, Inelastic nuclear rainbow scattering method INRS, Asymptotic normalization coefficients method ANC) to the analysis of some nuclear reactions provide evidence of existing in ⁹Be, ¹¹B, ¹²C, ¹³C the excited states whose radii exceed those of the corresponding ground states by ~ 30%. Two types of structure of these “size isomers” were identified: neutron halo an α-clusters.

We discuss α-clustering using new experimental results on ¹⁸O and ¹⁸Ne nuclei.

Experiments confirm a variety of cluster structures in many light nuclei. The observation of nuclear halos at drip-lines has accentuated the question of the degrees of freedom for bound and low-lying continuum states. In these cases the many-body dynamics of nuclear structure may be well approximated by few-body cluster models that often suggest conceptually simple approaches explaining successfully many features of light nuclei. Thus few-body cluster models have been successfully used for description of the nuclear structure of weakly bound halo nuclei and their emergent cluster degrees of freedom. They have attractive features supplying in a most transparent way the asymptotic behavior and continuum properties of weakly bound systems. Such models assume a separation in internal cluster (core) degrees of freedom and the relative motion of few-body constituents. Such separation is only an approximation, and low-lying states appear where the core cannot be considered as inert system and additional degrees of freedom connected to excited core states have to be taken into account. For fixed total angular momentum a coupling to excited core states having different spins involves additional partial waves into the consideration. This allows to account for some emergent (collective) core degrees of freedom and gives a more realistic description of nuclear properties. It is an analogue to increasing the number of shells within the framework of shell-model approaches. Some examples from recent nuclear structure exploration within few-body halo cluster models are presented.

Differential cross-sections of the ¹¹B + α inelastic scattering at E(α) = 65 leading to the most of the known ¹¹B states at the excitation energies up to 14 MeV were measured. The data analysis was done by DWBA and in some cases by the modified diffraction model allowing determining the radii of the excited states. The radii of the states with excitation energies less than ~ 7 MeV with the accuracy not less than 0.1-0.15 fm coincide with the radius of the ground state. This result is consistent with the traditional view of the shell structure of the low-lying states in ¹¹B. Most of the observed high-energy excited states are distributed among four rotational bands. The moments of inertia of band states are close to the moment of inertia of the Hoyle state of ¹²C. The calculated radii, related to these bands, are 0.7 - 1.0 fm larger than the radius of the ground state, and are close to the radius of the Hoyle state. These results are in agreement with existing predictions about various cluster structure of ¹¹B at high excitation energies. The state with the excitation energy 12.56 MeV, I^π = 1/2⁺, T = 1/2 and the root mean square radius R ~ 6 fm predicted in the frame of the alpha condensate hypothesis was not found. The observed level at 12.6 MeV really has T = 1/2, probably, I^π = 3/2⁺ and the radius close to that of the ground state.

The analysis of the differential cross-sections of the elastic and inelastic ¹³C + α scattering at E (α) = 65 MeV was done. The experiment was carried out at the Cyclotron of the Jyväskylä University, Finland. The radii of the states: 8.86 (1/2⁻), 3.09 (1/2⁺) and 9.90 (3/2⁻) MeV were determined by the Modified diffraction model (MDM). The radii of the first two levels are enhanced relatively that of the ground state of ¹³C, confirming the suggestion that the 8.86 MeV state could be an analogue of the Hoyle state in ¹²C and the 3.09 MeV state has a neutron halo. Preliminary analysis shows that the predicted radius enhancement for the 9.90 MeV state does not take place.

The excited states of heavy helium isotopes ^6,7He were studied in stopped pion absorption on ^10,11B nuclei. In three reaction channels ¹¹B(π⁻, dt)⁶He, ¹⁰B(π⁻, pt)⁶He and ¹⁰B(π⁻, dd)⁶He the ⁶He state with E_x = 3.5(3) MeV and Г = 3.1(4) MeV has been observed. At high excitations new levels of ⁶He have been found with E_x = 9.3(2) MeV, Г = 1.0(4) MeV, E_x = 22(1) MeV, Г = 2.7(1.4) MeV and E_x = 27.0(8) MeV, Г = 2.5(1.1) MeV. Excitation spectrum of ⁷He has been studied in three reaction channels ¹¹B(π⁻, pt)⁷He, ¹¹B(π⁻, dd)⁷He and ¹⁰B(π⁻, pd)⁷He. For the first time in one experiment it was observed three low-lying narrow (Г<0.5 MeV) states with E_x = 3.1(1), 4.9(2) and 6.7(2) MeV. At high excitations new levels have been found with E_x = 19.8(3) MeV, Г = 1.5(3) MeV and E_x = 24.8(4) MeV, Г = 4.6(7) MeV.

The nucleon or core stripping reactions of halo nuclei on light targets are studied using the diffraction theory of reactions with weakly bound nuclei. An improved version of the approximation of a small target's radius (compared to the size of a halo nucleus) is formulated. Simple analytical expressions for the differential cross section and the longitudinal momentum distribution of observed particles that allow us to calculate them with good accuracy are obtained.

A study of inelastic scattering and single-particle transfer reactions was performed by alpha and ³He beams on a ⁹Be target at energy about 50 MeV. Angular distributions of the differential cross sections for the ⁹Be(α,α')⁹Be*, ⁹Be(α,³He)¹⁰Be, ⁹Be(α,t)¹⁰B, ⁹Be(³He,⁶Li)⁶Li and ⁹Be(³He,⁶Be)6He reactions were measured. Experimental angular distributions of the differential cross sections for the ground state and a few low-lying states were analyzed in the framework of the optical model, coupled channels and distorted-wave Born approximation. The information on the cluster structure of the reaction products are obtained. An analysis of the spectroscopic factors was performed.

The charge topology of the events of coherent dissociation of ¹¹C and ¹²N of an energy of 1.2A GeV in nuclear track emulsion is presented and its compared is given with the appropriate data on the nuclei ⁷Be, ^8,10B, ^9,10C and ¹⁴.

The following sections are included:

• Introduction
• Hybrid microscopical optical potential model
• Density distributions model
• ^10,11Be+p elastic scattering
• ¹¹Be + ¹²C elastic scattering
• The ¹¹Be cluster model and momentum distributions of fragments
• Final conclusions
• Acknowledgements
• References

Different factors influencing the sub-barrier fusion enhancement owing to neutron rearrangement with positive Q values are studied. It was found that opposite to existing opinion the presence of positive Q values is necessary but not sufficient to observe enhancement of the sub-barrier fusion. “Rigidity” of colliding nuclei with respect to collective excitations plays a crucial role for the sub-barrier fusion enhancement due to neutron rearrangement. A special attention is paid to the peculiarities of fusion of light exotic nuclei.

Experimental excitation functions for near-barrier neutron transfer in ^3,6He+¹⁹⁷Au reactions have been measured and analyzed. Time-dependent Schrödinger equation and coupled channel equations for external neutrons of ^3,6He and ¹⁹⁷Au nuclei have been solved numerically taking into account spin-orbit interaction and Pauli exclusion principle.

Fusion cross sections induced by ^4,6,8He and ⁷Li were studied using different reactions [(⁴He+²⁰⁹Bi, ⁴He+²⁰⁸Pb, ⁴He+¹⁹⁷Au), (⁶He+²⁰⁹Bi, ⁶He+²⁰⁶Pb, ⁶He+¹⁹⁷Au) and (⁸He+²⁰⁹Bi, ⁸He+²⁰⁴Pb, ⁸He+¹⁹⁷Au)], these reactions were used to determine the influence of the heavy targets on the fusion excitation function mechanism. The reactions [⁴He+²⁰⁸Pb, ⁶He+²⁰⁶Pb, ⁸He+²⁰⁴Pb] give the same compound nuclei ²¹²Po and the reactions (⁶He+²⁰⁹Bi and ⁷Li+²⁰⁸Pb) give the same compound nuclei ²¹⁵At. These reactions were used to determine the influence of the compound nuclei on fusion excitation function mechanism. Theoretical calculations were done using the Channel Coupling code of the NRV using W. S. Surface with different parameters (V_o, r_o, ^Colr_o, a and ћωβ) for all reactions. The current study has shown that, large enhancement in the fusion cross sections at energies at the Coulomb barrier were observed only in the reactions ⁶He+²⁰⁶Pb and ⁸He+²⁰⁴Pb compared with ⁴He+²⁰⁸Pb and slightly or no enhancement were observed in the reactions ^6,8He+²⁰⁹Bi and ^6,8He+¹⁹⁷Au compared with reactions induced by ⁴He.

Above Coulomb barrier cross sections of fission fragment production were measured in reactions of ¹¹B with ¹⁹⁷Au target. Induced-activity method was used for measurement the fission decay channel of the composite nuclei. Systematic of the fission fragment charge and mass distributions was used for fission cross section calculation. Fission fraction of the composite nuclei decay was compared with PACE-4 mode calculations. Estimated suppression for fission fraction followed the complete fusion have been obtained 35%.

We present an analysis of the ⁶He+⁹Be elastic scattering angular distributions at two energies above the Coulomb barrier, E_cm= 9.72 and 12.78 MeV. The analysis was performed using an approach based on a cluster optical model for the ⁶He projectile. The total reaction cross sections have been obtained from the elastic scattering and a considerable enhancement has been observed in comparison with stable systems.

Total reaction cross section excitation functions σ_R(E) were measured for ⁶He secondary beam particles on ¹⁸¹Ta, ⁵⁹Co, ^natSi and ⁹Be targets in a wide energy range by direct and model-independent method. This experimental method was based on prompt n-γ 4π-technique applied in event-by event mode. A high efficiency CsI(Tl) γ-spectrometer was used for the detection of reaction products (prompt γ-quanta and neutrons) accompanying each reaction event. Using the ACCULINNA fragment-separator 6He fragments (produced by ¹¹B primary beam with ⁹Be target) are separated and transported to n-γ shielded experimental cave at FLNR JINR. The measured total reaction cross section data σ_R(E) for the above mentioned reactions are compared with a theoretical calculation based on the optical potential with the real part having the double-folding form.

The total nuclear reaction cross sections (σ_R) measurements have long been of interest since they tell us about the radii and transparency of these nuclei and give clues to understanding of their structure. For studies of unstable nuclei, in particular the physical properties of halo nuclei and the neutron skin thickness, it is valuable to know not only the root-mean-square radii (rms) but it is important to know the details of nucleusnucleus potentials. Our goal was to study total reaction cross sections (σ_R) by a direct measurement technique (the so-called beam attenuation or transmission method) which allows to extract model independent information. The interaction radii for ⁶He, ^8,9Li were extracted, which are in agreement with the previous measurement at the similar energies (about a few tens of AMeV) Our results show a tendency of increasing radii as function of mass of the secondary targets.

In the framework of the macroscopic optical model and semi-microscopic folding model, the authors have carried out a joint analysis of the experimental data (angular scattering distributions and total reaction cross sections) for the interaction of ⁶He- ions with ⁹Be- nuclei at energies from 1.37 to 25 MeV/A. The energy dependences of the total cross sections for reactions at low energies have been obtained and the radii of interaction of ⁶He nuclei have been determined.

The two-proton decays of the low-lying states of ¹⁷Ne populated in the ¹H(¹⁸Ne,d)¹⁷Ne transfer reaction were studied. The two-proton width of the ¹⁷Ne first excited state at 1.288 MeV is of importance for two-proton radioactivity theory and nuclear astrophysics applications. Dedicated search of the two-proton emission off this state was performed leading to new upper limit Γ_2p/Γ_γ~1.3 × 10⁻⁴.

We propose to search for the ⁷H g.s. using the quasifree (α,2α) knockout reaction from ¹¹Li having a spatially extended halo. In the quasi-free scattering ⁴He(¹¹Li,2α)⁷H reaction an α-particle is knocked out from ¹¹Li by the alpha target nucleus and the detection of these two α-particles is sufficient to extract the missing mass of ⁷H. The use of telescopes composed of a set of micro-strip Si deterctors provides a reconstruction of the vertex position inside the target with an accuracy of about ±100 μm. This accuracy also allows a very thick target which is only limited by the energy loss of the outgoing α-particles.

The 6Be excitation spectrum obtained in the 1H(6Li,6Be)n reaction provides detailed correlation information about the 0+ ground state and _rst excited 2+ state. Inuence of reaction mechanism on the formation of observed spectra is discussed.

The talk is focused on several most exciting problems of present-day nuclear physics. First of all these are the state of affairs in production and study properties of super-heavy elements (stability of these nuclei with increasing of Z number, methods of their production, nearest experiments and further progress, search of SHE in cosmic rays, etc.). Then the problems of neutron rich nuclei (their astrophysical significance, possible reaction mechanisms for the production of heavy neutron rich nuclei, studying neutron rich nuclei with closed neutron shells including those located at the neutron drip line and beyond it) are discussed. The next subject is strange nuclei and antimatter. Extension of the nuclear map into the two additional directions would broaden significantly our comprehension of the nuclear matter. The fundamental problem of vacuum decay (spontaneous formation of electron-positron pairs) in super-strong electric field appearing in collisions of very heavy (U-like) nuclei is also discussed. This problem attracts recently new and great interest owing to our deeper understanding of the process and new experimental possibilities.

Substantial information on nuclear shells which determine the stability of superheavy nuclei, can be achieved from the measurement of decay properties of isotopes of element 120. Using existing data measured up to elements 116 and 118 at FLNR in Dubna, estimates of shell-correction energies and fission barriers are deduced and compared with model calculations. The results indicate that the probability for re-separation of target and projectile like nuclei in the entrance channel of the reaction is less then assumed in some of the existing cross-section calculations. This finding together with technical reasons favors the reaction ⁵⁴Cr + ²⁴⁸Cm for synthesis of element 120. A first part of the experiment was already performed in 2011. The results will be presented in a forthcoming paper.

Multinucleon transfer processes in low-energy heavy ion collisions open new field of research in nuclear physics, namely, production and studying properties of not-yet- explored heavy neutron rich nuclei. Beams of very heavy U-like ions are needed to produce new long-living isotopes of transfermium and superheavy elements. Beams of medium-mass ions can be used for the production of neutron rich nuclei located along the neutron closed shell N=126 (the last waiting point) having the largest impact on the astrophysical r-process. Low-energy multinucleon transfer reactions is a very effective tool also for the production and spectroscopic study of light exotic nuclei. The corresponding cross sections are found to be 2 orders of magnitude larger as compared with high energy fragmentation reactions.

Review of the discovery and investigation of the “Island of stability” of superheavy nuclei at the separator DGFRS in the ²³⁸U-²⁴⁹Cf+⁴⁸Ca reactions is presented. The synthesis of the heaviest nuclei, their decay properties, and methods of identification are discussed. The results are compared with the data obtained in the chemistry experiments performed at the IVO+COLD setup and at the separators SHIP, BGS, and TASCA. The role of shell effects in the stability of superheavy nuclei is demonstrated by comparison of the experimental and theoretical data. The recent experiment aimed at the investigation of the region of neutron-deficient nuclei produced in the ²³⁹Pu+⁴⁸Ca reaction is described. Future experiments at DGFRS aimed at the study of superheavy nuclei are considered.

A relativistic approach to describe nuclear and in general strongly interacting matter is introduced and discussed. Here, not only the nuclear forces but also the masses of the nucleons are generated through meson fields. Within this framework it is possible to calculate properties of finite nuclei at a level of accuracy similar to dedicated relativistic nuclear structure models. Due to the more general approach, a wider range of properties of hadronic states can be investigated. A number of results for heavy and neutron-rich nuclei toward the drip line are presented.

Results of a new series of experiments on the study of production cross section and decay properties of the neutron-deficient isotopes of Flerovium are reported. Superheavy nuclide ²⁸⁴Fl was produced in fusion reaction ²³⁹Pu+⁴⁸Ca. The measured cross-section for producing a new spontaneously fissioning isotope ²⁸⁴Fl shows a dramatic deviation from theoretical predictions.

Both relativistic Dirac-Fock (DF) correlated, CCSD(T), and the density-functional theory (DFT) methods with various GGA exchange-correlation potentials agree on an increase in the M-Au bond strength from M = Cn to Fl. This means that the adsorption energy of Fl on gold, as measured by gas-phase chromatography experiments, must be larger for Fl than for Cn. For the weak (van der Waals) interactions, the trend to an increase in bonding from Cn₂ to Fl₂ obtained at the DFT level of theory is also confirmed by the DF CCSD(T) calculations. Thus, for comparative studies, relativistic DFT is a very reliable and efficient tool. First calculations of adsorption of TlOH and element 113OH on a hydroxylated quartz surface are reported.

Mathematical model of heavy and superheavy nuclei production in intensive pulsed neutron fluxes of explosive process is developed. The pulse character of the process allows dividing it in time into two stages: very short rapid process of multiple neutron captures with higher temperature and very intensive neutron fluxes, and relatively slower process with lesser temperature and neutron fluxes. The model was also extended for calculation of the transuranium yields in nuclear explosions takes into account the adiabatic character of the process, the probabilities of delayed fission, and the emission of delayed neutrons. Also the binary starting target isotopes compositions were included. Calculations of heavy transuranium and transfermium nuclei production were made for “Mike”, “Par” and “Barbel” experiments, performed in USA. It is shown that the production of transfermium neutron-rich nuclei and superheavy elements with A ~ 295 is only possible when using binary mixture of starting isotopes with the significant addition of heavy components, such as long-lived isotopes of curium, or californium.

We report an attempt to obtain general information about superheavy elements chemistry from modeling of molecular electronic structure of their simplest binary compounds. We apply this approach to comparative study of chemical properties of element 113 and its nearest homologue, thallium. Basing on the obtained results we discuss possible chemical pseudo-homologues of element 113.

Two-component density functional theory in its non-collinear formulation combined with the accurate relativistic electronic structure model defined by shape-consistent small-core pseudopotentials (PP/RDFT) provides a robust basis of efficient computational schemes for predicting energetic and structural properties of complex polyatomic systems including superheavy elements (SHEs). Because of the exceptional role of thermochromatography in the experiments on the “chemical” identification of SHEs with atomic numbers Z ≥ 112, we focus on the description of the adsorption of single SHE atoms on the surfaces of solids through cluster modeling of adsorption complexes. In some cases our results differ significantly from those of previous theoretical studies. The results of systematic comparative studies on chemical bonding in simple molecules of binary compounds of SHEs and their nearest homologs with most common light elements, obtained at the PP/RDFT level and visualized through the “chemical graphs”, provide the understanding of the general chemistry of SHEs which at present cannot be derived from the experimental data. These results are used to discuss the main trends in changing chemical properties of the elements in the given group of the periodic table and demonstrate the specificity of SHEs.

Energies of the giant Gamow–Teller and analog resonances – E_G and E_A, are presented, calculated using the microscopic theory of finite Fermi system. The calculated differences ΔEG-A between EG and EA energies go to zero in heavier nuclei indicating the restoration of Wigner SU(4)-symmetry. The ΔE_G-A values are in good agreement with the experimental data. The average deviation is 0.30 MeV for the 33 considered nuclei. The ΔE_G-A values were calculated for heavy and superheavy nuclei up to mass number A = 300. The Wigner SU(4)-symmetry restoration for heavy and superheavy nuclei is confirmed.

The possibility of synthesizing a doubly magic superheavy nucleus, ²⁹⁸Fl₁₈₄, is investigated on the basis of fluctuation-dissipation dynamics. In order to synthesize this nucleus, we must generate more neutron-rich compound nuclei because of the neutron emissions from excited compound nuclei. The compound nucleus ³⁰⁴Fl has two advantages to achieving a high survival probability. First, because of low neutron separation energy and rapid cooling, the shell correction energy recovers quickly. Secondly, owing to neutron emissions, the neutron number in the nucleus approaches that of the double closed shell and the nucleus attains a large fission barrier. Because of these two effects, the survival probability of ³⁰⁴Fl does not decrease until the excitation energy E^*= 50 MeV. These properties lead to a rather high evaporation residue cross section. Also, using the dynamical model, we study fission fragment mass distributions from the fission of U and Pu isotopes at low excitation energies. It was found that the shell effect of the potential-energy landscape has a dominant role in determining the mass distribution. The present approach can serve as a basis for more refined analysis.

The study of mass-energy distributions of binary fragments obtained in the reactions of ³⁶S, ⁴⁸Ca, ⁵⁸Fe and ⁶⁴Ni ions with the ²³²Th, ²³⁸U, ²⁴⁴Pu and ²⁴⁸Cm at energies below and above the Coulomb barrier is presented. For all the reactions the main component of the distributions corresponds to asymmetrical mass division typical for asymmetric quasifission process. To describe the quasifission mass distribution the simple method has been proposed. This method is based on the driving potential of the system and time dependent mass drift. This procedure allows to estimate QF time scale from the measured mass distributions. It has been found that the QF time exponentially decreases when the reaction Coulomb factor Z₁Z₂ increases.

Photonuclear reaction yields were studies at the range of giant dipole resonance for medium-mass targets and the probabilities for population of different final states were deduced and analyzed. In addition to the expected statistical trends expressed in the influence of the reaction threshold and of the product spin, there are observed the microstructure manifestations due to the individual level schemes of the products. The internal status of nucleons and their single-particle orbital momentum also make influence onto the reaction yield. The effects are isolated on the scale from tens % to orders of magnitude for the probability and branching ratio in reactions at modest energy.

The complex structure of low-lying as well as those of high-lying states is discussed within multiphonon approach. The approach is based on Quasiparticle-Phonon Model. This microscopic model goes beyond the quasiparticle random-phase approximation by treating a Hamiltonian of separable form in a microscopic multiphonon basis. It is therefore able to describe the anharmonic features of collective modes. In the case of low-lying part of excitations the model has close correspondence with the proton-neutron interacting boson model. Within the model highly-excited single-particle states in nuclei are coupled with the excitations of a more complex character, first of all with collective phonon-like modes of the core. Although, on the level of one and two-phonon admixtures, the fully chaotic GOE regime is not reached, the eigenstates of the model carry significant degree of complexity that can be quantified with the aid of correlation invariant entropy.

Starting from a Skyrme interaction the Gamow-Teller (GT) strength in the Q_β- window has been studied within a microscopic model including the 2p-2h configuration effects. The suggested approach enables one to perform the calculations in very large configuration spaces. As a result, the β⁻-decay halflife is decreased due to the 2p − 2h fragmentation of GT states. Using the Skyrme interaction SGII with tensor terms we study this reduction effect for the neutron-rich N = 82 isotones below the doubly magic nucleus ¹³²Sn. Predictions are given for ¹²⁶Ru and ¹²⁸Pd in comparison to ¹³⁰Cd which is the r-process waiting-point nucleus.

The previously reported levels and assignments to ^151,152,153Pr have recently been called into question about the mass assignment to the reported bands. Recently prompt γ-rays in coincidence with isotopically-identified fission fragments using VAMOS++ and EXOGAM, produced using ²³⁸U on a ⁹Be target have been reported. To clarify the recently questioned mass assignments of ^151,152,153Pr, the γ-γ-γ-γ data from ²⁵²Cf (SF) by using Gammasphere and the GANIL in-beam mass- and Z-gated γ-spectra were combined to assign transitions and levels in these Pr isotopes. The transitions and levels previously assigned to ^151,153Pr have been confirmed by the M-Z gated spectra. The transitions previously assigned to ¹⁵²Pr are now assigned to ¹⁵¹Pr by using the M-Z gated spectra. Three new bands with 24 new transitions in ¹⁵²Pr and one new band with 7 new transitions in ¹⁵³Pr are identified. The Yttrium fission partners of all the ^151,152,153Pr have Gaussian yield distributions that peak at the 3n channel.

For the first time the brake-up of the fission fragments crossing metal foil was observed. The effect takes place predominantly in front impacts. To treat the data we suppose the bulk of the fragments from the conventional binary fission to be borne in shape-isomer states which look like di-nuclear systems with magic cores.

The collinear cluster decay in ²⁵²Cf(sf,fff), with three cluster fragments of different masses (e.g.¹³²Sn,⁵²⁻⁴⁸Ca,₆₈₋₇₂Ni), which has been observed by the FOBOS group in JINR, has established a new decay mode, the CCT (Collinear Cluster Tri-partition) of heavy nuclei. The same type of ternary fission decay has been observed in the reaction ²³⁵U(n_th,fff). This collinear “true ternary fission” of heavy nuclei has been predicted many times in theoretical works during the last decades. In the present contribution we show that other ternary decay modes occur, in particular the symmetric ternary fission (FFF) into three fragments of almost equal size (e.g. Z=98→Zi = 32, 34, 32) in the same system. The different ternary fission channels are predicted with potential energy (PES) calculations for two mass parameters, M1(A1) and M3(A3). The deeper valleys point to the favored decay channels. An important aspect for the probability of the ternary decay modes are the internal barriers, which are presented here. The PES's show pronounced minima for several choices for favored ternary fragmentations. With these predictions, a variety of collinear ternary fission modes in the experimental data have been established.

According to theoretical predictions there is a possibility of an existence of shapeisomeric states in heavy nuclei based on ternary pre-scission configurations. Expected life time ranges up to some milliseconds. Preliminary result of the experiment dedicated to searching for such ling-lived shape-isomeric states in the compound system from the ²³⁵U(n_th, f) reaction is presented.

Fission study using multi-nucleon transfer reaction will be discussed. This approach has an advantage that we can study fission of neutron-rich nuclei which cannot be accessed by particle or charged-particle capture reactions. Unique feature in our setup is that we can produce fission data for many nuclei using many transfer-channels. Also wide excitation energy range can be covered in this set up, allowing us to measure the excitation energy dependence of the fission properties. Preliminary data obtained in the ¹⁸O + ²³⁸U reaction will be presented..

Within the framework of the hydrodynamic approach to the description of heavy-ion collisions at intermediate energies, we carried out the investigation of a non-equilibrium equation of state. We considered the compression, expansion and freeze-out stages of a hot spot formed in heavy-ion collisions. The calculated energy spectra of protons produced in heavy-ion collisions have been compared with the experimental data.

The evaporation residues excitation functions for the reactions ⁴⁰Ar+¹⁴⁴Sm→¹⁸⁴Hg and ⁴⁰Ar+¹⁶⁶Er→²⁰⁶Rn were measured at the energies below and above the Coulomb barrier (E_lab=142-207 MeV) using a mass-separator MASHA. The experimental data were compared with theoretical calculations using a Channel Coupling Model. The influence of experimental beam energy spread on the excitation functions was taking into account. It was found that structure of xn-cross sections correlate strongly with the nuclear structure of colliding nuclei.

This The β- decay of ^70-74Co and other species in the vicinity of ⁷⁸Ni has been investigated following the relativistic fission of a ²³⁸U primary beam at the Radioactive Ion Beam Factory facility in RIKEN, as part of the EURICA campaign. Extremely neutron-rich nuclei from Mn to Cu were produced and stopped in a state-of-the-art β-decay spectroscopy setup after their in-flight identification. The unprecedented high intensity of the primary beam, I = 10 pnA, ensures the access to a broad number of low-lying excited states in their daughters. In the present contribution, specific details on the setup and the experimental techniques employed are described. As well, the preliminary results are discussed.

Correlation measurements of the stopped π⁻-meson absorption reactions ¹⁰B(π⁻, dt)X and ¹¹B(π⁻, tt)X were carried out at low energy pion channel of LAMPF with the two-arm multilayer semiconductor spectrometer of charged particles. The analysis of twodimensional distributions (Dalitz' diagram) and the momentum distribution of the residual nucleus allowed to identify the process of pion absorption on the intranuclear lithium clusters 5,6Li and to get the evidence on the existence of the configurations ⁵Li + ⁵He_g.s and ⁶Li + ⁵He_g.s in the boron nuclei ^10,11B. The levels of ⁸Li^* isotope with the resonance parameters (E_x, Г): (8.7 ± 0.2, 1.9 ± 0.4) MeV and (10.1 ± 0.3, 4.0 ± 1.3) MeV were observed for the first time. These states break up with the triton emission: ⁸Li^* → t + ⁵He..

The possibility of observing proton beta decay in a scattering system proton- (high Z) nucleus is examined from a simplified perspective. The proton is supposed to move on a Rutherford trajectory and the extra proton energy necessary to compensate the mass difference with respect to decay products can be provided on the account of potential energy of the proton in the electrostatic field of the nucleus.

The principal parameters (charge, mass, time of life, conditions of generation and observation) of en exotic quasiparticles had been determined and nuclear processes involved its participation are considered. The theoretical explanation to the time delay effect of an exotic quasiparticles generation is represented in present report.

The discussion of results of experimental observation of twin an exotic quasiparticles (or vertexes) produced in laser plasma are done. Such quantum objects are more nuclear “quiet” and considered as possible candidates on roles of neutral Higgs particles or dyons. The synchronous motions of two quantum interacting exotic quasiparticles had been detected as well as its periodic temporal nuclear activation.

At RIKEN RI Beam Factory (RIBF), having all the experimental facilities in place, the uranium-beam intensity recorded 25pnA in 2014. With use of this powerful beam many experiments are begin performed by variety of researchers from all over the world, producing a lot of new data which were just a dream in several years ago. Recent status of RIKEN RI Beam Factory (RIBF) is presented with future prospects in science and an accelerator plan.

Six heaviest chemical elements with atomic numbers 113-118 that filled the eighth row of the Mendeleev's Periodic Table [1-10] were synthesized in reactions of ⁴⁸Ca ions with actinide targets in the experimental studies carried out over the recent years. Over 50 new isotopes of elements 104–118 with maximum neutron excess were for the first time produced and their decay properties were determined in these investigations. The new isotopes considerably filled up the Chart of the nuclides and expanded it up to Z=118 and N=177 (Figure 1)…

The superconducting fragment separator (Super-FRS) will be one of the main scientific instruments of the future FAIR facility. This versatile high-resolution spectrometer allows for a variety of exciting experiments in atomic, nuclear and hadron physics. Future directions are presented in this contribution.

The Texas A&M Cyclotron Institute has been studying nuclear science with radioactive beams for the past two decades with in-flight production and separation using the MARS spectrometer. The TREX upgrade to the facility will augment this fast beam capability with the ability to deliver both stopped and reaccelerated radioactive ions. This paper will discuss the present capabilities and future plans of the Texas A&M Cyclotron Institute.

The development of high power lasers and the combination of such novel devices with accelerator technology has enlarged the science reach of many research fields, in particular High energy, Nuclear and Astrophysics as well as societal applications in Material Science, Nuclear Energy and Medicine. The European Strategic Forum for Research Infrastructures (ESFRI) has selected a proposal based on these new premises called “ELI” for Extreme Light Infrastructure. ELI will be built as a network of three complementary pillars at the frontier of laser technologies. The ELI-NP pillar (NP for Nuclear Physics) is under construction near Bucharest (Romania) and will develop a scientific program using two 10 PW class lasers and a Back Compton Scattering High Brilliance and Intense Low Energy Gamma Beam , a marriage of Laser and Accelerator technology at the frontier of knowledge. In the present paper, the technical description of the facility, the present status of the project as well as the science, applications and future perspectives will be discussed.

The ALTO facility consists of two accelerators in the same area. A Tandem accelerator dedicated to stable (ions and cluster) beam physics and a linear electron accelerator dedicated to the production of radioactive beams. This gives a unique opportunity to have in the same place cluster beams for interdisciplinary physics and stable and radioactive beams for astrophysics and nuclear physics.

In-flight separators used in heavy-element research will be discussed including new experimental developments. Based on almost 40 years of experience with in-flight separators for superheavy element research a next generation separation system for heavy-ion fusion and transfer products is due. The use of radioactive beams at Coulomb barrier energy available at the Low-Energy Branch of the SuperFRS for isotope production will be discussed briefly.

High-resolution spectrometer experiments with energetic incident ion beams characterized by a large phase space represent a great challenge for in-flight rare-isotope facilities. Projectile fragments and fission products separated in flight have an inevitable large angular and momentum spread due to their stochastic creation processes and the atomic interactions in the production target, degrader and detector materials. Solutions are to use dedicated ion-optical systems like energy-loss spectrometers and isochronous systems, or methods which reduce the incident phase space by cooling and energy bunching methods. Recent experiments with the fragment separator FRS have demonstrated the success of these efforts and methods.

The project of a new in-flight fragment separator ACCULINNA-2 at the U-400M cyclotron (FLNR, JINR) is being realized to enhance the research opportunities offered by the existing fragment separator ACCULINNA. The new facility will produce high intensity RIBs with Z=1÷36 in the lowest energy range (~8÷50 MeV/nucleon) attainable for in-flight separators. We discuss the “first day” experiments (commissioning of ACCULINNA-2 is planned for 2015) and long-range program (seven year plan for 2017-2023), as well as further developments of this facility.

The proposal EXPERT is suggested for the Super-FRS Collaboration physics program [1] in the NUSTAR Collaboration of the project FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is aimed at studies of the nuclear landscape beyond the proton and neutron drip-lines and intends to push researches up to limits of nuclear existence. By combining the EXPERT instrumentation (two tracking techniques applied for radioactivity and nuclear decays in-flight), the phenomena of multi-nucleon radioactivity, resonance decays in continuum, beta-delayed exotic decays and exotic excitation modes can be studied via observations of particle emissions, including the 2p, 4p, 6p, n, 2n, 4n, 6n channels.

Collisions of bare heavy nuclei implemented by means of merging beam technique are suggested for the study of remarkable phenomena appearing in very strong fields created when distance between the nuclear surfaces approaches zero. Suggested here is to build a collider with two beams of actinide nuclei merging within a common straight section. Principal parameters of this collider are outlined.

Typical application of Si detectors in high energy physics is tracking. A variety of Si strip and pixel trackers is meanwhile built and successfully operated. In nuclear physics and astrophysics, in addition to tracking, energy loss measurements are very important. Recently, application to time measurements have been suggested and successfully tested. Applications of Si detectors on the examples of experiments performed at GSI, Darmstadt are presented, together with the ideas of using them in the future at FAIR and ACCULLINA2 facilities.

It will be interesting to perform study of neutron rich nuclei, for example ^5,7H, ^9,10He, etc. There are several planned experiments on the ACCULINNA, ACCULINNA-2 facilities to make such study with using of the neutron detectors. The prototype of array of the neutron detectors based on stilbene crystals was designed and manufactured in Flerov Laboratory of Nuclear Reactions, JINR Dubna for this purpose.

The Modular Neutron Array (MoNA) in conjunction with the large-gap Sweeper magnet at the NSCL is an effective setup to explore neutron-unbound states and has been operating for ten years. Neutron-unbound nuclei beyond the drip-line as well as neutron unbound excited states of bound nuclei have been populated primarily using proton removal reactions. A recent example, the search for 3n emission of the decay of ¹⁵Be to1 ¹²Be, is discussed.

Resonant Ionization Laser Ion Source (RILIS), based on the stepwise excitations of atomic transitions, offers an outstanding combination of excellent elemental selectivity and high ionization efficiency. It has become a powerful and versatile tool for generation of pure radioactive isotope beams at on-line mass separator facilities worldwide. Initiated in 2009, IPN-Orsay has installed RILIS in the Isotope Separators on-line (ISOL) system at the photofission facility ALTO, which aims to the measurements of the nuclear properties of exotic nuclei through β-γ and β-n spectroscopy, among other techniques. RILS at ALTO (RIALTO) consists of two dye lasers pumped with a 532nm 10kHz Nd:YAG laser with the wavelength extension options via frequency doubling/tripling of nonlinear crystals. Gallium and Zinc isotopic beams were successfully delivered by RIALTO starting from 2011. To develop the laser ionization scheme for different elements and test optimal operational parameters for on-line radioactive beam deliveries, an off-line reference cell has been built. The preliminary result of the first commence of the off-line reference cell will be presented in this paper.

New data on β-decay properties on neutron-rich ^82,83Ga measured at TETRA neutron detector are reported. Pure beams of ^82,83Ga were produced at ALTO-facility using laser ionization technique. While T_1/2 (⁸²Ga) = 0.604(11)s , P_1/2 (⁸²Ga) = 22(2)% and T_1/2 (⁸³Ga) = 0.312(1)s are in agreement with literature values, P_1/2 (⁸³Ga) = 85(4)% was found to be significantly higher as compared to other available data. Therefore, we came to the conclusion that ⁸³Ga is a much stronger neutron emitter as it was reported previously.

For research and control of characteristics of radiation fluxes, radioactive sources in particular, for example, in paper [1], a spectrometer and methods of data measurement and processing based on the multichannel counter of time intervals of accident events appearance (impulses of particle detector) MC-2A (SPC “ASPECT”) were created. The spectrometer has four independent channels of registration of time intervals of impulses appearance and correspondent amplitude and spectrometric channels for control along the energy spectra of the operation stationarity of paths of each of the channels from the detector to the amplifier. The registration of alpha-radiation is carried out by the semiconductor detectors with energy resolution of 16-30 keV. Using a spectrometer there have been taken measurements of oscillations of alpha-radiation 239-Pu flux intensity with a subsequent autocorrelative statistical analysis of the time series of readings.

Motivation and status of the VEGA (Velocity-Energy Guide based Array) project is presented. One armed fission fragments spectrometer with an electrostatic guide system is proposed for installation at the vertical experimental channel of the IBR-2 reactor. Scientific program aimed at investigation of new multi-body decays of actinides, shapeisomeric states in fission fragments and fission modes is reported.

A project of the high-resolution magnetic analyzer MAVR is proposed. The analyzer will comprise new magnetic optical and detecting systems for separation and identification of reaction products in a wide range of masses (5-150) and charges (1-60). The magnetic optical system consists of the MSP-144 magnet and a doublet of quadrupole lenses. This will allow the solid angle of the spectrometer to be increased by an order of magnitude up to 30 msr. The magnetic analyzer will have a high momentum resolution (10^-4) and high focal-plane dispersion (1.9 m). It will allow products of nuclear reactions at energies up to 30 MeV/nucleon to be detected with the charge resolution ~1/60. Implementation of the project is divided into two stages: conversion of the magnetic analyzer proper and construction of the nuclear reaction products identification system. The MULTI detecting system is being developed for the MAVR magnetic analyzer to allow detection of nuclear reaction products and their identification by charge Q, atomic number Z, and mass A with a high absolute accuracy. The identification will be performed by measuring the energy loss (ΔE), time of flight (TOF), and total kinetic energy (TKE) of reaction products. The particle trajectories in the analyzer will also be determined using the drift chamber developed jointly with GANIL. The MAVR analyzer will operate in both primary beams of heavy ions and beams of radioactive nuclei produced by the U400 - U400M acceleration complex. It will also be used for measuring energy spectra of nuclear reaction products and as an energy monochromator.

Reconstruction of the heavy ion masses in the time-of-flight spectrometry is known to be a complicated task due to distortions both in timing and measuring of the ions energy using PIN diodes. Original procedure which takes into account simultaneously pulse height defect (PHD) and plasma delay for unbiased mass reconstruction was tested in series of experiments at the LIS setup using degrader foils.

Radon and mercury isotopes were produced in multi nucleon transfer (⁴⁸Ca + ²³²Th) and complete fusion (⁴⁸Ca + ^naturalNd) reactions, respectively. The isotopes with given masses were detected using two detectors: a multi-strip detector of the well-type (made in CANBERRA) and a position-sensitive quantum counting hybrid pixel detector of the TIMEPIX type. The isotopes implanted into the detectors then emit alpha- and betaparticles until reaching the long lived isotopes. The position of the isotopes, the tracks, the time and energy of beta-particles were measured and analyzed. A new software for the particle recognition and data analysis of experimental results was developed and used. It was shown that MASHA+ TIMEPIX setup is a powerful instrument for investigation of neutron-rich isotopes far from stability limits.

Accelerator Laboratory at the Physics Department of the University of Jyväskylä (JYFL) has a long tradition in development, construction, and implementation of new instruments and detection techniques. This line of research has been recently extended from Nuclear- and Relativistic Heavy Ion collisions to Astroparticle and Neutrino Physics. In my presentation I briefly review the latest developments and provide the highlights of the measurements conducted over the period since EXON 2012 [1]. Special emphasis is given to the research conducted in collaboration with JINR Dubna, Kurchatov Institute, INR, and Khloplin Radium Institute.

The reaction ³⁴S + ¹⁸⁶W at E_lab = 160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays coincident with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. The coupling of the ORGAM and CORSET setups enables the FF-γ coincident measurement which offers the opportunity to extract the isotopic distribution of the fragments of different masses formed in the aforementioned reaction and to find the exact neutron multiplicity, the average spin and average angular momenta. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

The following sections are included:

• AUTHOR INDEX
• LIST OF PARTICIPANTS
• PHOTO BLOCK