Search

New experimental data of angular distributions for the elastic and inelastic scattering of 10B ions by 6Li nuclei were obtained at the energy Elab(10B) = 51 MeV for the ground and excited 2.18 – 5.7 MeV states of 6Li and 0.7 – 6.56 MeV states of 10В. These elastic and inelastic scattering data and known from literature data of elastic scattering of 6Li ions by 10В nuclei at energy Elab(6Li) = 30 MeV were analyzed within coupled-reaction-channels method. The 6Li + 10B elastic and inelastic scattering data, spin reorientation of 6Li and 10В, as well as more important transfer reactions, were included in the channels-coupling scheme. The Woods - Saxon potential parameters, as well as 6Li and 10В deformation parameters, were deduced. The mechanisms of the 6Li + 10В inelastic scattering were studied within the model of collective nuclei excitations, the differences of the 6Li + 10В elastic scattering from using 6Li + 10В, 7Li + 10В and 6Li + 11В potentials were observed, the contributions of one- and two-step transfers were deduced using spectroscopic amplitudes for transfer particles calculated within the translation invariant shell model.

In this work we numerically calculate cross sections of the reactions 6Li ( n , n ′ γ ) 6Li and 7Li ( n , n ′ γ ) 7Li reactions in the region of neutron kinetic energy E n = 0.5 − 20 MeV. Neutron-nucleus interaction is defined in terms of the three-body problem wherein the target-nucleus is a bound two-body system. Dynamics in all two-body segments is described by the coupled Lippman-Schwinger equations with separable potentials. Free parameters of these potentials are chosen based on a fairly good description of elastic scattering phase shifts and radiation cross sections: t α → γ 7 Li, d α → γ 6 Li, n d → γ t . The system of three-body strongly interacting particles is described by the Faddeev equations. Radiative relaxation of the excited nucleus is effectively taken into account by the electromagnetic vertex inserted in the three-body scattering amplitude. Total cross sections and also poorly measured double differential cross sections of 6Li ( n , n ′ γ ) 6Li and 7Li ( n , n ′ γ ) 7Li are obtained and briefly analyzed.

As Beryllium is an important element in primary nucleosynthesis, its nuclear reaction cross-sections induced by charged projectiles need to be measured precisely. The astrophysical S ( E i ) factors were measured in the ultra-low energy range from E lab = 18 to 100 keV in 2-keV increments (42 points). Both the astrophysical S ( E ) curve ( S bare ( 0 ) = 16.2 ± 1.8 MeV b ) and the screening energy ( U s = 545 ± 98 eV ) were deduced. In regard to astrophysical applications of the S bare ( E ) curve, the present results are consistent with Zahnow's direct measurement. For the long-standing problem of ‘abnormal’ screening effect, our screening energy result also agrees with that obtained using the Trojan-horse method ( U s = 676 ± 86 eV ) but smaller than Zahnow's value ( 900 ± 50 eV ), although all results are much larger than that obtained in the adiabatic limit (∼264 eV).

BNCT (Boron Neutron Capture Therapy) is a therapeutic modality used to irradiate tumors cells previously loaded with the stable isotope 10B, with thermal or epithermal neutrons. This technique is capable of delivering a high dose to the tumor cells while the healthy surrounding tissue receive a much lower dose depending on the 10B biodistribution. In this study, therapeutic gain and tumor dose per target power, as parameters to evaluate the treatment quality, were calculated. The common neutron-producing reaction 7Li(p,n)7Be for accelerator-based BNCT, having a reaction threshold of 1880.4 keV, was considered as the primary source of neutrons. Energies near the reaction threshold for deep-seated brain tumors were employed. These calculations were performed with the Monte Carlo N-Particle (MCNP) code. A simple but effective beam shaping assembly (BSA) was calculated producing a high therapeutic gain compared to previously proposed facilities with the same nuclear reaction.

The 6Li + n seven-nucleon nuclear system is studied at low energies within a microscopic approach based on the multichannel algebraic version of the resonating group model. The partial and total cross sections for the 6Li(n, t)4He reaction are calculated. The contributions of the various partial cross sections to the energy dependence of the total cross section are considered. The results of the calculations are found to be in a good agreement with experimental data.

Within the standar dmodel of Big Bang Nucleosynthesis (BBN), there is a cosmological lithium problem, which consists in a substantial difference between calculated data on the abundances of the isotopes 6Li and 7Li and those that were found from observational astronomy. An attempt at measuring the cross section for the main 6Li production reaction 2H(4He, γ)6Li induced by the interaction of 4He+ ions with deuterons at collision energies less than the lower boundary of the BBN energy range was made in the present study. Upper limits on the cross sections for the reaction in question were set.

Undoped lithium-6 enriched glasses coated with pure cerium (99.9%) with a gold protection layer on top were heated at three different temperatures (500, 550, and 600 °C) for varied durations (1, 2, and 4 h). Diffusion profiles of cerium in such glasses were obtained with the conventional Rutherford backscattering technique. Through fitting the diffusion profiles with the thin-film solution of Fick’s second law, diffusion coefficients of cerium with different annealing temperatures and durations were solved. Then, the activation energy of cerium for the diffusion process in the studied glasses was found to be 114 kJ/mol with the Arrhenius equation.

The results based on the spectroscopy of superheavy hydrogen isotopes (4−7H), heavy helium isotopes (6,7He), and heavy lithium isotopes (7−12Li) produced in stopped pion absorption by light nuclei were analyzed. Search for nuclear states was performed in inclusive and correlation measurements of missing mass spectra. A broad range of excitation energies studied in correlation measurements provided the possibility of search for isobaric analog states and cluster resonances. A comparison with experimental and theoretical results of other authors was conducted.

In this study, the effect of reactor irradiation on the processes of interaction of hydrogen with liquid lithium and a lithium capillary-porous system (CPS) is considered. The experiments are carried out by the gas-absorption method with use of a specially designed ampoule device. The results of investigation of the interaction of hydrogen with liquid lithium and a lithium CPS under conditions of reactor irradiation are described; namely, these are the temperature dependences of the rate constant for the interaction of hydrogen with liquid lithium at different reactor powers, the activation energies of the processes, and the pre-exponential factor in the Arrhenius dependence. The effect of increasing absorption of hydrogen by the samples under investigation as a result of the reactor irradiation is fixed. The effect can be explained by increasing mobility of hydrogen in liquid lithium due to hot spots in lithium bulk and the interaction of helium and tritium ions (formed as a result of the nuclear reaction of 6Li with neutron) with a surface hydride film.

The cross sections for the (t, p) reactions on the lithium isotopes 9,11Li were calculated within a theoretical approach based on employing integral equations of the four-body problem in the Alt—Grassberger-Sandhas formalism and the multiparticle shell model. This made it possible to determine the wave functions for the relative motion of various clusters and the nuclear core and to calculate, on their basis, the root-mean-square radii of nuclei of the isotopes 9,11Li and the spatial structure of their neutron periphery. It is shown that the 9Li nucleus has virtually no neutron halo. The 11Li nucleus is a Borromean halo nucleus. The two-neutron periphery of this nucleus manifests itself in both spatial configurations, a dineutron and a cigar one, the respective root-mean-square radii being large (about 6.5 to 6.9 fm).

The differential cross section for the interaction of 7Be nuclei with protons was measured in the momentum-transfer region extending up to a value of 0.5 GeV/c at which 7Be decay to 3He and 4He fragments was not accompanied by the emergence of other charged particles. In the momentum-transfer region extending up to about 100 MeV/c, the cross section is strongly suppressed in just the same way as in the case of the dissociation of 7Li nuclei on a proton target through the 3H+4He channel. The total reaction cross section is 10 ± 4 mb. The mean transverse-momentum transfer in observed events is 233 ± 6 MeV/c, the dispersion of its distribution being about 63 MeV/c. The interactions in question were detected in photoemulsion irradiated with 7Be nuclei originating from a charge-exchange process involving 7Li nuclei accelerated to the momentum of 1.7 GeV/c per nucleon at the nuclotron of the Joint Institute for Nuclear Research (Dubna).

Lithium titanate enriched by 6Li isotope is considered as a candidate of tritium breeding materials for fusion reactors due to its excellent performance. The reuse of burned Li2TiO3 pebbles is an important issue because of the high costs of 6Li-enriched materials and waste considerations. For this purpose, reprocessing of Li2TiO3 pebbles by graphite bed method was developed. Simulative Li2TiO3 pebbles with low-lithium content according to the expected lithium burn-up were fabricated. After that, Li2TiO3 pebbles were re-fabricated with lithium carbonate as lithium additives, in order to gain the composition of lithium titanate with a Li/Ti ratio of 2. The process was optimized to obtain reprocessed Li2TiO3 pebbles that were suitable for reuse as ceramic breeder. Density, porosity, grain size and crushing load of the reprocessed pebbles were characterized. This process did not deteriorate the properties of the reprocessed pebbles and was almost no waste generation.

A core-shell type adsorbent was proposed for lithium isotope separation by chromatography. Concentration profiles and its time variation in the column were numerically simulated. It became clear th...

A method for constructing dispersive optical potentials is proposed for calculating single-particle energies in isotopic chains of spherical and nearly spherical nuclei up to nucleon drip lines. The potential of this method is demonstrated by calculating the neutron and proton single-particle energies in calcium, nickel, and zirconium isotopes. The results agree well with experimental data available for stable isotopes. Predictive calculations of single-particle spectra are performed for isotopes lying far from the beta-stability valley. A comparison of the results with the energies of nucleon separation from nuclei of mass number A and A+1 revealed features of the single-particle spectrum that are characteristic of nuclei containing classical and nonclassical magic numbers of nucleons.

We have carried out an experiment to search for a neutron-rich hypernucleus, 6 H, by the 6 Li(π − , K + ) reaction at pπ− =1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the 6 H hypernucleus neither below nor above the 4 H+2n particle decay threshold. An upper limit of the production cross section for the bound 6 H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

The spatial structure of lithium isotopes is studied with the aid of the charge-exchange and (t, p) reactions on lithium nuclei. It is shown that an excited isobaric-analog state of 6Li (0+, 3.56MeV) has a halo structure formed by a proton and a neutron, that, in the 9Li nucleus, there is virtually no neutron halo, and that 11Li is a Borromean nucleus formed by a 9Li core and a two-neutron halo manifesting itself in cigar-like and dineutron configurations.

In this article we report the longitudinal relaxation times (T(1)) of various (6)Li salts ((6)LiI, (6)LiCl and (6)LiNO(3)) in D(2)O and H(2)O, measured in low magnetic fields (B(0)=3.5mT). This investigation serves the purpose of clarifying the relaxation behavior of different (6)Li solutions and different concentrations. The measurement were undertaken to establish a framework for future applications of hyperpolarized (6)Li in medical imaging, biological studies and investigations of lithium ion batteries. Time will pass during the transport of hyperpolarized lithium ions to the sample, which leads to a polarization loss. In order to store polarization as long as possible, it is necessary to examine which (6)Li salt solution has the longest relaxation time T(1). Longitudinal relaxation times of (6)Li salts in D(2)O and H(2)O were investigated as a function of concentration and the most extended T(1) was found for (6)LiI in D(2)O and H(2)O. In agreement with the theory the relaxation time T(1) of all (6)Li salts increase with decreasing concentration. In the case of (6)LiI in H(2)O an inverse behavior was observed. We assume that the prolonged T(1) times occur due to formation of (6)LiOH upon the solution of (6)LiI in H(2)O, which settles as a precipitate. By diluting the solution, the precipitate continuously dissolves and approaches T(1) of (6)LiOH (T(1)∼28s), leading to a shorter T(1) relaxation time.

The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ( 6 Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% 6 Li. In this paper, a new lithium isotope separation technique using an ionic-liquid impregnated organic membrane is proposed. In order to separate and concentrate lithium isotopes, only lithium ions are able to move through the membrane by electrodialysis between the cathode and the anode in lithium solutions. Preliminary experiments of lithium isotope separation were conducted using this phenomenon. Organic membranes impregnated with TMPA-TFSI and PP13-TFSI as ionic liquids were prepared, and the relationship between the 6 Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the 6 Li isotope separation coefficient in this method (about 1.1–1.4) was larger than that in the mercury amalgam method (about 1.06).

We report on the development of a fast neutron detector using a liquid scintillator doped with enriched Li-6. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A Li-6 concentration of 0.15 % by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the Li-6. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this 6Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape discrimination method for differentiating between electronic and nuclear recoil events based on the Matusita distance between a normalized observed waveform and nuclear and electronic recoil template waveforms. The details of the measurements are discussed along with specifics of the data analysis and its comparison with the Monte Carlo simulation.

Lithium, owing to its many advantages, is of immense interest to the fusion community for its use as plasma facing component (PFC) material. Various experiments are under progress in the Center for Plasma Material Interactions (CPMI) at the University of Illinois at Urbana Champaign (UIUC) aimed at understanding the plasma–lithium interactions. In one such experiment called Solid/Liquid Lithium Divertor Experiment (SLiDE), it was recently observed that the flow of liquid lithium in the presence of magnetic fields is dominated by thermoelectric Magnetohydrodynamic (TEMHD) effects. To describe these results accurately, a knowledge of the thermoelectric properties of lithium is essential. For this purpose, an apparatus to measure the Seebeck coefficient of lithium was developed. Using this apparatus, the Seebeck coefficient of lithium as a function of temperature has been obtained. The Seebeck coefficient of lithium-7 is found to gradually increase from 11 μV/K to 25 μV/K, as the temperature is raised from 25 °C to 240 °C. These measurements are in good agreement with Kendall’s thermoelectric measurements on natural Li. Furthermore, using the same apparatus, the thermoelectric curve of lithium-6 is obtained and for the first time are reported in this paper.

A new measurement of differential cross sections for elastic p 6Li scattering in the energy range 0.35–1.2 MeV was performed. A partial-wave analysis of the data obtained in this way was carried out, and potentials simulating the p 6Li interaction were constructed. Various experiments devoted to studying elastic p 6Li scattering over the broad energy range of 0.5–50 MeV were analyzed on the basis of the optical model. By using the potentials obtained from the partial-wave analysis, the possibility of describing the astrophysical S factor for radiative proton capture on 6Li at low energies was considered within the potential cluster model involving forbidden states.

We present two experiments measuring the parity-violating asymmetry (P-odd) of tritons emission in the reaction 6Li(n,α)3H and γ-quanta emission in the reaction 10B(n,α)7Li* → 7Li + γ with polarized cold neutrons, aiming at estimation of the weak meson-nucleon coupling constants. These experiments started in the PNPI, Gatchina and continued in the ILL, Grenoble. We describe an integral method to measure P-odd asymmetry and the two experiments. The results of our measurements are: $\alpha{}_{P-odd}^{6Li}=(-8.8\pm2.1)\cdot10^{-8}$ and $\alpha{}_{P-odd}^{10B}=(0.8\pm3.9)\cdot10^{-8}$ .

Results of a comparative analysis of processes leading to the production of mirror nuclei 7Li and 7Be in 16Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. A comparison of associated multiplicities of accompanying particles is performed. The first results on the mean multiplicity of neutrons appearing as fragments are described.

The Coulomb dipole induced dynamic polarization potentials for 6He + 209Bi and 11Li + 208Pb systems within the framework of Feshbach’s formalism with a motive to ascertain the presence or absence of threshold anomaly have been studied. As a result of this study, the threshold anomaly has been found to be present for both systems. It has also been found that at deep sub-barrier energies the imaginary part either starts increasing or at least remains unchanged which indicates the presence of the breakup threshold anomaly. In addition, the Coulomb breakup transmission factors for both systems have been found to have maximum value below and near-barrier energies, but at very high energies due to closure of the breakup channel the breakup transmission coefficients quickly becomes zero.

The possibility of producing exotic 6He nuclei in the 7Li(γ, p) reaction with 22 MeV electron beam at the MT-25 microtron in the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (FLNR JINR), is studied. The 6He yield from the Li2CO3 target made up 6 × 105 s−1 per 1 μA of the electron beam current. The obtained result is quite promising, taking into account the further improvement of the target unit, the possibility of using another lithium compound, and the increase in the target material temperature and the electron beam current up to 20 μA. The application of this approach for the further production of a monochromatic beam of accelerated 6He nuclei with an intensity on the order of 107 s−1 would make a large number of experiments on investigating the structure of this nucleus and the mechanisms of nuclear reactions with its participation feasible. This method for obtaining 6He nuclei may turn out to be one of the most optimal (and inexpensive) currently available.

The neutron capture cross-sections and the capture γ-ray spectra of 56 Fe and 57 Fe have been measured in the neutron energy range from 10 to 90 keV. Pulsed keV-neutrons were produced from the 7 Li( p , n ) 7 Be reaction by bombarding a lithium target with a 1.5-ns bunched proton beam from a 3 MV Pelletron accelerator. The incident neutron spectrum on the capture sample was measured using a time-of-flight method with a 6 Li-glass detector. The capture γ-rays emitted from an iron or standard gold sample were detected with a large anti-Compton NaI(Tl) spectrometer. The capture yield of the iron or gold sample was obtained by applying a pulse-height weighting technique to the corresponding capture γ-ray pulse-height spectrum. The capture cross-sections of 56,57 Fe were derived with errors less than 5% using the standard capture cross-sections of 197 Au. The capture γ-ray spectra were obtained by unfolding the observed capture γ-ray pulse-height spectra. The present results for the capture cross-sections were compared with the previous measurements and the evaluated values of ENDF/B-VII.0 and JENDL-3.3. The Maxwellian-averaged capture cross-sections of 56 Fe and 57 Fe at 30 keV are derived as 12.22 ± 2.06 mb and 44.48 ± 7.56 mb, respectively.

Systematic studies of nuclear astrophysical reactions induced by lithium isotopes using the unstable ion beam facility GIRAFFE in CIAE were performed. We have measured the angular distributions of some single nucleon transfer reactions, such as 8 Li(d,p) 9 Li, 8 Li(d,n) 9 Be and 8 Li(p,d) 7 Li in inverse kinematics, and derived the astrophysical S-factors or reaction rates for 8 Li(n, γ ) 9 Li and 8 Li(p, γ ) 9 Be by using asymptotic normalization coefficient (ANC) or spectroscopic factor.

An isotope separation technique using effusive emission of vapors from the heated molybdenum boat is presented. The technique is applied for the separation of the lithium isotopes. Lithium fluoride with natural isotopic abundance was chosen for evaporation and it was achieved by resistive heating of the molybdenum boat with an exit orifice in the center that provides a point source emission. Glass substrates were placed in a semi-circle around the source of evaporation at different positions of peripheral region to deposit the evaporated material. A non-commercial laboratory developed linear Time of Flight (TOF) mass spectrometer was used for isotopic abundance measurements of lithium in the deposited thin films. The dependence of the size of exit orifice on the separation is also studied for the three exit orifices with diameters of 0.3, 0.6 and 1.0 mm. The separation factors of the isotopes as a function of different peripheral locations are calculated and presented. The abundance of the 6 Li isotope has been increased up to 16% on the peripheral positions.

Lithium was electrochemically inserted into tin(IV) Sulfide (SnS2) from a mixed solution of ethylene carbonate and methyl ethyl carbonate containing 1 M LiClO4, and the lithium isotope effect accompanying the insertion was investigated. The x value of LixSnS2 after the electrolysis ranged from 0.279 to 4.914. The single-stage separation factor, S, ranged from 1.006 to 1.023 at 25°C with the lighter isotope, 6Li, being preferentially fractionated into the SnS2 phase. This tendency of lithium isotope effects was the same as that observed for tin metal and the opposite to that observed for tin(IV) oxide (SnO2)in the direction of the lithium isotope fractionation.

The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.

The differential cross sections for elastic proton scattering on the unstable neutron-rich nuclei 8Li and 9Li at E = 700 and 60 MeV per nucleon were considered. The 8Li nucleus was treated on the basis of the three-body α-t-n model, while the 9Li nucleus was considered within the α-t-n and 7Li-n-n models. The cross sections in question were calculated within Glauber diffraction theory. A comparison of the results with available experimental data made it possible to draw conclusions on the quality of the wave functions and potential used in the calculations.

Nuclei of $^7$Li were accelerated at the JINR Nuclotron. After the charge-exchange reaction involving these nuclei at an external target a second $^7$Be beam of energy 1.23A GeV was formed. This beam was used to expose photo-emulsion chambers. The mean free path for inelastic $^7$Be interactions in emulsion $\lambda$=14.0$\pm$0.8 cm coincides within the errors with those for $^6$Li and $^7$Li nuclei. More than 10% of the $^7$Be events are associated with the peripheral interactions in which the total charge of the relativistic fragments is equal to the charge of the $^7$Be and in which charged mesons are not produced. An unusual ratio of the isotopes is revealed in the composition of the doubly charged $^7$Be fragments: the number of $^3$He fragments is twice as large as that of $^4$He fragments. In 50% of peripheral interactions, a $^7$Be nucleus decays to two doubly charged fragments. The present paper gives the channels of the $^7$Be fragmentation to charged fragments. In 50% of events, the $^7$Be fragmentation proceeds only to charged fragments involving no emission of neutrons. Of them, the $^3$He+$^4$He channel dominates, the $^4$He+d+p and $^6$Li+pchannels constitute 10% each. Two events involving no emission of neutrons are registered in the 3-body $^3$He+t+p and $^3$He+d+d channels. The mean free path for the coherent dissociation of relativistic $^7$Be nuclei to $^3$He+$^4$He is 7$\pm$1 m. The particular features of the relativistic $^7$Be fragmentation in such peripheral interactions are explained by the $^3$He+$^4$He 2-cluster structure of the $^7$Be nucleus., Comment: 10 pages, 3 figures, 3 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 5-9 Dec 2005

Since 1970's when double-folding model, based on M3Y interaction, had to be renormalized to fit the elastic scattering of weakly bound 6,7Li and 9Be nuclei, we learned that preconceptions based on the highly successful experience of the optical model on stable nuclei could not be simply extrapolated to the scattering of exotic nuclei. Recently, we have shown some evidences of long range mechanisms in 6He induced reactions that lead to the loss of flux in the elastic channel at kinematic conditions that suggest the nuclei are well beyond the strong absorption radius [O. R. Kakuee, M. A. G. Alvarez, M. V. Andres, S. Cherubini, T. Davinson, A. Di Pietro, W. Galster, J. Gomez-Camacho, A. M. Laird, M. Lamehi-Rachti, I. Martel, A. M. Moro, J. Rahighi, A. M. Sanchez-Benitez, A. C. Shotter, W. B. Smith, J. Vervier, P. J. Woods. Nucl. Phys. A 765, (2006) 294]. Even so, the use of nuclear reactions as an spectroscopic tool to investigate the nuclear structure of weakly bound nuclei requires a deep understanding of the reactions induced by these nuclei. Therefore, precise experimental measurements of the elastic scattering of exotic nuclei on a variety of targets, as well as the measurements of the main reaction channels are required in order to converge experimentally and theoretically to this understanding. With this aim a campaign of experiments involving different institutions and collaborations is being carefully established and going ahead at several radioactive ion beam (RIB) facilities: ISOLDE (CERN), CRC (Be), GSI (Ge) and TRIUMPH (Ca). The main idea is to measure the scattering of He, Li, and Be isotopes, and perform an intensive theoretical treatment, besides promoting some necessary instrumental development. In particular we participate in the low energy branch of the FAIR project where we take part in the tracking studies and developments.

Lithium was electrochemically inserted into SnO2 and Fe2O3--SiO2 binary oxide from the mixed solution of ethylene carbonate and methyl ethyl carbonate containing 1 M LiClO4, and the lithium isotope effect accompanying the insertion was investigated. Tin(IV) oxide showed a slight selectivity towards the heavier isotope of lithium with the separation factor (S) ranging from 0.982 to 0.999 at 25°C. Fe2O3--SiO2 binary oxide, on the other hand, showed no specific lithium isotope selectivity with S scattered around unity at the same temperature. These results were reasonably understood by assuming the reduction of the metals in the host materials from Sn(IV) to Sn(0) and from Fe(III) to Fe(II) and the formation of lithium oxide upon Li insertion.

Intermediate mass fragment emission for reactions of $^{32}\text{S} +\,^{51}\text{V},\,^{109}$Ag, and $^{238}\text{U}$ has been studied. Double differential cross sections were analysed in terms of the generalised moving source model yielding charge distributions. Isotope ratios show strong fragment mass dependencies. The data were successfully reproduced by the coalescence model as well as by statistical multifragmentation model calculations. Quantum molecular dynamics model calculations were not so successful., accepted by European Journal of Physics A

We have performed CDCC calculations for collisions of $^{7}$Li projectiles on $^{59}$Co, $^{144}$Sm and $^{208}$Pb targets at near-barrier energies, to assess the importance of the Coulomb and the nuclear couplings in the breakup of $^{7}$Li, as well as the Coulomb-nuclear interference. We have also investigated scaling laws, expressing the dependence of the cross sections on the charge and the mass of the target. This work is complementary to the one previously reported by us on the breakup of $^{6}$Li. Here we explore the similarities and differences between the results for the two Lithium isotopes. The relevance of the Coulomb dipole strength at low energy for the two-cluster projectile is investigated in details., 6 pages, 5 figures

The elastic and inelastic cross sections of $^{6}\mathrm{Li}$ on $^{28}\mathrm{Si}$ at 240 MeV, and quasielastic cross section of $^{7}\mathrm{Li}$ and $^{11}\mathrm{Li}$ on $^{28}\mathrm{Si}$ at $177.8$ and 319 MeV, respectively, are analyzed with the coupled-channels method. The collective nuclear level density is used to determine the deformation parameter regarding to the first-excited state of $^{28}\mathrm{Si}$. The results are in agreement with the experimental data and indicate the need of using a nuclear structure model such as nuclear level density to reduce the ambiguity between the optical model parameters and the deformation parameter. Additionally, the spin-orbit potential is found to have an important role in reproducing the data of the quasielastic scattering of $^{7}\mathrm{Li}$ and $^{11}\mathrm{Li}$ on a $^{28}\mathrm{Si}$ target.

Results of several experiments aimed at exploring the nuclear spatial structure of neutron-rich He and Li isotopes are presented and briefly discussed. The study of the density distributions in these nuclei by small-angle proton elastic scattering at intermediate energy is considered in more detail. The performed investigations allow one to obtain information on the total matter distributions, radii of the matter, neutron and proton distributions, effective and internal core sizes, halo sizes, and spatial correlations of the halo nucleons in the studied nuclei.

We present a novel approach for the treatment of realistic nucleon-nucleon interactions in nuclear many-body systems. A unitary correlation operator is used to explicitly introduce short-range central and tensor correlations in many-body states. The correlated interaction is used as an effective interaction in nuclear structure calculations. Results for Lithium isotopes including proton and neutron distributions, radii as well as magnetic moments and quadrupole moments are shown. Molecular resonances in the 16O−16O system are given as a first application in reaction theory.

Within Glauber diffraction theory, the vector analyzing power iT11 is calculated at three energies of positively charged pions, 134, 164, and 194 MeV, incident to 7Li nuclei. These energy values lie in the region of the Δ33 resonance in π±N interaction, the resonance maximum being at 180 MeV. The calculation of iT11 was performed with several model 7Li wave functions, including the αt-cluster and shell-model ones. The properties of π+7Li scattering are found to be sensitive to the structural features of the target nucleus. A comparison of the results of the calculations with experimental data shows that the wave functions in question and the potentials used to calculate them are quite appropriate.

Within the (α, n, p) three-body model, the s-wave 6Li → α + d vertex constant G01 and the asymptotic normalization coefficient C01 (these two quantities are proportional to each other) for the wave function describing the 6Li nucleus in the α + d channel are calculated by solving Faddeev equations for various sets of nucleon-nucleon and αN potentials. The resulting values of G01 and C01 are used to calculate the astrophysical factor S(E) for the radiative-capture reaction d(α, γ)6Li at energies in the range E = 0–600 keV. The calculated values of G01 and C01 appear to be sensitive to the form of the pair potentials used. It is shown that, upon correctly taking into account the contributions of the E2 and E1 multipolarities, the values of S(E) in the region E < 150 keV are determined primarily by the values of C01 and of the 6Li binding energy in the α + d channel.

A novel method for the determination of nuclear charge radii of lithium isotopes is presented. Precise laser spectroscopic measurements of the isotope shift in the lithium 2s → 3s transition are combined with highly accurate atomic physics calculation of the mass dependent isotope shift to extract the charge-distribution-sensitive information. This approach has been used to determine the charge radii of 8,9Li for the first time.

Hydrogen and helium recycling behaviour from solid and liquid lithium has been observed with optical spectroscopy focused on H? and He?I in a newly built facility: VEHICLE-1 (the Vertical and Horizontal positions Interchangeable test stand for Components and Liquids for fusion Experiments). The plasma density and electron temperature in VEHICLE-1 are of the order of 1010?cm?3 and around 4?eV, respectively. The ion bombarding energy is varied from the floating potential to 100?V, applying negative dc bias voltages on lithium targets. The lithium temperature range is from 30 to 300??C. It has been found that hydrogen recycling from standing liquid lithium is significantly reduced, compared with that from solid lithium, presumably due to the formation of lithium hydride particulates that can be transported beyond the implantation depth. In contrast, despite its chemical inertness, helium recycling from both moving and standing solid lithium at room temperature has been found to be noticeably reduced, relative to that from liquid lithium. Lattice imperfections in solid lithium appear to play an important role in reducing steady state helium recycling.

The specific heats of TiB{sub 2} and {sup 6}LiF have been measured from 0.5 to 30 K as part of a larger project in the construction of a neutron spectrometer. For this application, the measured specific heats were used to extrapolate the specific heats down to 0.1 K with lattice, electronic, and Schottky equations for the respective samples. The resultant specific heat values at 0.1 K for TiB{sub 2} and {sup 6}LiF are 4.08 x 10{sup -4} {+-} 0.27 x 10{sup -4} J/K/mol and 9.19 x 10{sup -9} {+-} 0.15 x 10{sup -9} J/K/mol, respectively.

The differential cross sections for elastic and inelastic scattering of α particles on 11B nuclei at energies of 40 and 50 MeV were measured in the entire angular range. The measured angular distributions were analyzed in terms of the optical model, the distorted-wave Born approximation, and the coupled-channel-method. Optical model potentials and quadrupole (β2) and hexadecapole (β4) deformation parameters were found from this analysis. The rise in the cross sections at backward angles was shown to be associated with the transfer mechanism of the heavy 7Li cluster.

Direct and indirect methods have been developed for measurements of tritium production rates on different Li isotopes. The methods are mainly intended for design-oriented blanket experiments and are based on the activation of thin diagnostic pellets. In the direct method, the tritium activity bred from Li isotopes can be evaluated separately using two activated Li-containing pellets, measured by liquid scintillation counting. The method allows precise measurements of tritium activity in the pellet at a level of 2 Bq/g. The indirect method is based on the use of model activation reactions, 35 Cl(n,α) 32 P and 31 P(n,γ) 32 P, that possess a similar neutron spectrum sensitivity as direct tritium production reactions on 7 Li and 6 Li, respectively, and an effective measurement of the activation product of model reactions, 32 P, by Cherenkov radiation counting. The reaction rate of model reactions can be calibrated in order to obtain the TPR.

This work presents results on charged state topology of relativistic fragmentation of 6 Li and 7 Li nuclei at 4.5A and 3.8A GeV/c, respectively, on photoemulsion nuclei. The results would make it possible to answer some topical questions concerning the cluster structure of lithium isotopes. The isotopic composition of fragments and the channels of 6,7 Li fragmentation as well as the mean momenta ρβc of projectile fragments have been measured. Yields of 1 H (3 He ) appear to have the highest probability due to the fragmentation of 7 Li , while 2 H (4 He ) and 1 H (4 He ) are dominant through 6 Li -fragmentation process. The presence of exotic 6 He among fragmentation process is observed in 7 Li with yield 3% while 0.65% were found in 6 Li .

We performed an experiment to measure γ rays of hyperfragments produced by stopped K − reactions on light ( A ⩽ 12 ) targets (KEK-PS E509). We clearly observed an E2 transition ( 5 / 2 + → 1 / 2 + ) in 7ΛLi with 10B, 11B and 12C targets and obtained the γ-ray intensity to be ( 7.5 ± 1.6 ) × 10 −4 per stopped K − for 10B target. In addition, a candidate for a new hypernuclear γ ray was observed. These results show that this method is quite suitable for the systematic study of hypernuclei.

The UB3LYP/LanL2DZ level calculations were carried out for sixty-seven Li-M diatomic molecules of lithium between LiH and LiBi to explore the periodic properties of their 6Li-to-7Li isotopic reduced partition function ratios (rpfrs) and some other quantities. The Li-M bond distance, the frequency shift upon 7Li/6Li isotope substitution and the rpfr all show plots typical of any chemical and physical property which is a periodic function of the atomic number. The rpfr is strongly correlated with the Li-M bond stretching force constant except for LiH. The present calculations show that the rpfrs of diatomic molecules of group 2, group 12 and group 18 elements are relatively small, which reflects the filled electron shell and subshell characters of those elements. The results of the calculations and the consideration on chemical properties of elements suggest that zinc is a possible substitute for mercury in lithium isotope separation processes utilizing the redox reaction of lithium.

Quasielastic deuteron and triton knockout from 6Li and 7Li nuclei that was induced by a π−-meson beam of momentum p0 = 0.72 and 0.88 GeV/c was studied under conditions of full kinematics. The experiment was performed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) by using a 3-m magnetic spectrometer equipped with spark chambers. The distributions with respect to the momenta of quasideuteron and quasitriton internal motion, the excitation-energy spectra of residual nuclei, and the effective numbers of quasideuterons in 6Li and 7Li nuclei were obtained.