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Sample records for nuclei 6li 10b

  1. Nuclear structure with accurate chiral perturbation theory nucleon-nucleon potential: Application to 6Li and 10B

    Energy Technology Data Exchange (ETDEWEB)

    Navratil, P; Caurier, E

    2003-10-14

    The authors calculate properties of A = 6 system using the accurate charge-dependent nucleon-nucleon (NN) potential at fourth order of chiral perturbation theory. By application of the ab initio no-core shell model (NCSM) and a variational calculation in the harmonic oscillator basis with basis size up to 16 {h_bar}{Omega} they obtain the {sup 6}Li binding energy of 28.5(5) MeV and a converged excitation spectrum. Also, they calculate properties of {sup 10}B using the same NN potential in a basis space of up to 8 {h_bar}{Omega}. The results are consistent with results obtained by standard accurate NN potentials and demonstrate a deficiency of Hamiltonians consisting of only two-body terms. At this order of chiral perturbation theory three-body terms appear. It is expected that inclusion of such terms in the Hamiltonian will improve agreement with experiment.

  2. Alpha cluster states in light nuclei populated through the (6Li,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Borello-Lewin, Thereza; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy). Istituto Nazionale di Fisica Nucleare. Lab. Nazionali del Sud; Ukita, Gilberto Mitsuo [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Fac. de Psicologia

    2011-07-01

    Full text: The alpha cluster correlation is an important concept in the nuclear physics of light nuclei. The main purpose of the research program in progress is the investigation of the alpha clustering phenomenon in (x{alpha}) and(x{alpha}+{nu}) nuclei through the ({sup 6}Li,d) alpha transfer reaction. In fact, there is scarce experimental information on the subject, in particular associated with resonant states predicted near (x{alpha}) and (x{alpha}+{nu}) thresholds. Measurements of the {sup 12},{sup 13}C({sup 6}Li,d) {sup 16},{sup 17}O reactions, at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique. The work is under way and an experimental energy resolution of 30 keV was obtained. Near the (4{alpha}) breakup threshold in {sup 16}O, three narrow alpha resonances, not previously measured, were detected, revealing important {alpha} + {sup 12}C(G.S.) components. One of these resonances corresponds to the known 0{sup +} state at 15.1 MeV[5] of excitation that has probably, according to Funaki et al., the gas like configuration of the 4{alpha} condensate state, with a very dilute density and a large component of {alpha} + {sup 12}C(Hoyle) configuration. As was already mentioned, our experimental information points to the necessity of including the {alpha} + {sup 12}C(G.S.) component in the wave function. (author)

  3. Progress of analysis of dissociation of 10C, 10B and 12C nuclei in nuclear track emulsion

    Directory of Open Access Journals (Sweden)

    Artemenkov D. A.

    2017-01-01

    Full Text Available Recent findings related with the unstable nuclei 8Be and 9B in the coherent dissociation of relativistic nuclei 10C, 10B and 12C in nuclear track emulsion (“white”stars are highlighted. Selection of the 10C “white”stars accompanied by 8Be (9B leads to appearance of the distinct peak with a maximum at 4.1 ± 0.3 MeV in the excitation energy distribution of 2α2p ensembles. The 8Beg.s. nucleus is manifested in the coherent dissociation 10B → 2He + H with a probability of 25 ± 5 % including 13 ± 3 % of 9B decays. A probability ratio of the mirror channels 9B + n and 9Be + p is estimated to be 10 ± 1. Reanalysis of relativistic 12C dissociation in lead enriched emulsion revealed 9 3α-events corresponding to the Hoyle state.

  4. (p,px) reaction on /sup 6/Li and /sup 7/Li nuclei at incident proton energy of 70 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gorpinich, O.K.; Kadkin, E.P.; Kondrat' ev, S.N.; Lobach, Yu.M.; Pasechnik, M.V.; Saltykov, L.S.; Tokarevskij, V.V. (AN Ukrainskoj SSR, Kiev. Inst. Yadernykh Issledovanij)

    1983-01-01

    Measurements of two-dimensional coincidence spectra of charged particles from the /sup 6/Li(p, 2p)/sup 5/He, /sup 6/Li(p, p..cap alpha..)/sup 2/H, /sup 7/Li(p, pt)/sup 4/He, /sup 7/Li(p, p..cap alpha..)/sup 3/H reactions has been carried out using the equipment for simultaneous investigation of correlation of charged particles of different types. The /sup 6/Li(p, pd) reaction probability reaches the maximum value when the residual nucleus momentum is close to zero. This fact may confirm an existance of strong /sup 6/Li ..cap alpha..d-clusterization. The /sup 7/Li(p, pt) reaction occurs with the minimum probability in a quasi-free region that confirms /sup 7/Li ..cap alpha..t-structure. A direct comparison of particle two-dimensional spectra projections of (p, px) type reactions reveals that a probability of quasi-free scattering of proton on deuteron (triton) /sup 6/Li(/sup 7/Li) cluster is higher than quasi-free scattering on intranuclear protons. This fact is also confirmed by an assumption on ..cap alpha..d(..cap alpha..t)-cluster /sup 6/Li(/sup 7/Li) nucleus structure.

  5. (p, 2p) and (p, pn) reactions in /sup 6/Li and /sup 7/Li nuclei induced by medium-energy protons

    Energy Technology Data Exchange (ETDEWEB)

    Vdovin, A.I.; Loshchakov, I.I.

    1987-01-01

    In the t-matrix approximation we analyze the (p,2p) and (p,pn) reactions and inelastic proton scattering in lithium nuclei. Quasielastic nucleon scattering and core polarization are taken into account coherently in the calculation of the reaction matrix element. We use the intranuclear nucleon wave functions calculated with the modified Elton shell model. The quasielastic scattering is described with the help of the nonlocal realistic t-matrix of free pp (pn) scattering. The calculations are compared with experimental data at the incident-proton energies 46, 47, 49, 70, and 100 MeV. It is shown that in contrast to the impulse approximation the t-matrix approximation reproduces the experimental results.

  6. Production of antimatter $^{5,6}$Li nuclei in central Au+Au collisions at $\\sqrt{s_{NN}} = 200$ GeV

    CERN Document Server

    Sun, Kai-Jia

    2015-01-01

    Combining the covariant coalescence model and a blast-wave-like analytical parametrization for (anti-)nucleon phase-space freezeout configuration, we explore light (anti-)nucleus production in central Au+Au collisions at $\\sqrt{s_{NN}} = 200$ GeV. Using the nucleon freezeout configuration (denoted by FO1) determined from the measured spectra of protons (p), deutrons (d) and $^{3}$He, we find the predicted yield of $^{4}$He is significantly smaller than the experimental data. We show this disagreement can be removed by using a nucleon freezeout configuration (denoted by FO2) in which the nucleons are assumed to freeze out earlier than those in FO1 to effectively consider the effect of large binding energy value of $^{4}$He. Assuming the binding energy effect also exists for the production of $^5\\text{Li}$, $^5\\overline{\\text{Li}}$, $^6\\text{Li}$ and $^6\\overline{\\text{Li}}$ due to their similar binding energy values as $^{4}$He, we find the yields of these heavier (anti-)nuclei can be enhanced by a factor of a...

  7. Measurement of multinucleon transfer cross-sections in 58Ni,56Fe(12C, ); : 13,11C, 11,10B, 10,9,7Be, 8Be.s. and 7,6Li at (12C) = 60 MeV

    Indian Academy of Sciences (India)

    B J Roy; A Parmar; T Nandi; Biraja Mohanty; M Oswal; Sunil Kumar; A Jhingan; V Jha; D C Biswas

    2016-01-01

    Cross-sections for one- and multinucleon transfer reactions, namely, 58Ni(12C, 13C), 58Ni(12C, 11C), 58Ni(12C, 11B), 58Ni(12C, 10B), 58Ni(12C, 10Be), 58Ni(12C, 9Be), 58Ni(12C, 8Be.s.), 58Ni(12C, 7Be), 58Ni(12C, 7Li) and 58Ni(12C, 6Li) have been measured at an incident energy of 60 MeV. The reaction cross-section for the corresponding transfer channels in the system 12C+56Fe have also been measured under the same kinematical conditions. Angular distribution of the elastic scattering cross-section is measured at 60 MeV. The measured elastic scattering angular distributions for these two systems have been analysed using the optical model search code SFRESCO and the potential parameters are extracted. The multinucleon transfer data are analysed to obtain cross-section dependence on the number of nucleons transferred and on the ground state -values. The transfer probabilities for multinucleon stripping are extracted. A detailed comparison in the multiparticle stripping and elastic scattering cross-sections between these two systems are made to understand the mechanism of multinucleon transfer and possible role of two extra protons in 58Ni target nucleus as compared to the 56Fe core.

  8. 6Li foil thermal neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, Kiril D [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Chung, Kiwhan [Los Alamos National Laboratory; Macarthur, Duncan W [Los Alamos National Laboratory

    2010-01-01

    In this paper we report on the design of a multilayer thermal neutron detector based on {sup 6}Li reactive foil and thin film plastic scintillators. The {sup 6}Li foils have about twice the intrinsic efficiency of {sup 10}B films and about four times higher light output due to a unique combination of high energy of reaction particles, low self absorption, and low ionization density of tritons. The design configuration provides for double sided readout of the lithium foil resulting in a doubling of the efficiency relative to a classical reactive film detector and generating a pulse height distribution with a valley between neutron and gamma signals similar to {sup 3}He tubes. The tens of microns thickness of plastic scintillator limits the energy deposited by gamma rays, which provides the necessary neutron/gamma discrimination. We used MCNPX to model a multilayer Li foil detector design and compared it with the standard HLNCC-II (18 {sup 3}He tubes operated at 4 atm). The preliminary results of the {sup 6}Li configuration show higher efficiency and one third of the die-away time. These properties, combined with the very short dead time of the plastic scintillator, offer the potential of a very high performance detector.

  9. Triple α resonances in the 6Li + 6Li → 3α reaction at low energy

    Directory of Open Access Journals (Sweden)

    A. Tumino

    2015-11-01

    Full Text Available The 6Li + 6Li → 3α reaction has been measured in a kinematically complete experiment at 3.1 MeV of beam energy. The reaction mainly proceeds via intermediate 8Be states. The interaction between any two of the three α particles provides events with one, two or three 8Be interfering levels, with strong enhancement in the α–α coincidence yield. Evidence of three 8Be levels within the same 3α event suggests that one α particle is exchanged between the other two. This is a condition for Efimov states to occur in nuclei, for which no observation exists yet. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3α particle correlation.

  10. Triple α resonances in the {sup 6}Li + {sup 6}Li → 3α reaction at low energy

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A., E-mail: tumino@lns.infn.it [Facoltà di Ingegneria e Architettura, Università degli Studi di Enna “Kore”, Enna (Italy); INFN, Laboratori Nazionali del Sud, Catania (Italy); Bonasera, A.; Giuliani, G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Cyclotron Laboratory, Texas A& M University, College Station, TX (United States); Lattuada, M. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Milin, M. [Faculty of Science, University of Zagreb, Zagreb (Croatia); Pizzone, R.G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Spitaleri, C. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Tudisco, S. [INFN, Laboratori Nazionali del Sud, Catania (Italy)

    2015-11-12

    The {sup 6}Li + {sup 6}Li → 3α reaction has been measured in a kinematically complete experiment at 3.1 MeV of beam energy. The reaction mainly proceeds via intermediate {sup 8}Be states. The interaction between any two of the three α particles provides events with one, two or three {sup 8}Be interfering levels, with strong enhancement in the α–α coincidence yield. Evidence of three {sup 8}Be levels within the same 3α event suggests that one α particle is exchanged between the other two. This is a condition for Efimov states to occur in nuclei, for which no observation exists yet. The hyperspherical formalism for the low-energy three-body problem has been applied to point out the 3α particle correlation.

  11. Two-proton pickup studies with the (6Li,8B) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Weisenmiller, R.B.

    1976-12-03

    The (/sup 6/Li,/sup 8/B) reaction has been investigated on targets of /sup 26/Mg, /sup 24/Mg, /sup 16/O, /sup 13/C, /sup 12/C, /sup 11/B, /sup 10/B, and /sup 9/Be at a bombarding energy of 80.0 MeV, and on targets of /sup 16/O, /sup 12/C, /sup 9/Be, /sup 7/Li, and /sup 6/Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this reaction resembles that of the analogous (p,t) reaction. Additionally, these data demonstrate the dominance of spatially symmetric transfer of the two protons. On T/sub z/ greater than 0 targets the (/sup 6/Li,/sup 8/B) reaction was employed to locate two previously unreported levels (at 7.47 +- 0.05 MeV and 8.86 +- 0.07 MeV) in the T/sub z/ = 2 nuclide /sup 24/Ne and to establish the low-lying 1p-shell states in the T/sub z/ = /sup 3///sub 2/ nuclei /sup 11/Be, /sup 9/Li, and /sup 7/He. However, no evidence was seen for any narrow levels in the T/sub z/ = /sup 3///sub 2/ nuclide /sup 5/H nor for any narrow excited states in /sup 7/He. The angular distributions reported here are rather featureless and decrease monotonically with increasing angle. This behavior can be shown by a semi-classical reaction theory to be a consequence of the reaction kinematics. A semi-classical approach also suggests that the kinematic term in the transition matrix element is only weakly dependent upon the angular momentum transfer (which is consistent with simple Distorted Wave Born Approximation calculations). However, only qualitative agreement was obtained between the observed relative transition yields and semi-classical predictions, using the two-nucleon coefficients of fractional parentage of Cohen and Kurath, probably due to the limitations of the semi-classical reaction theory.

  12. Transport properties derived from ion-atom collisions: 6Li-6Li+ and 6Li-7Li+ Cases

    Science.gov (United States)

    Bouledroua, Moncef; Bouchelaghem, Fouzia; LPR Team

    2014-10-01

    This investigation treats quantum-mechanically the ion- atom collisions and computes the transport coefficients, such as the coefficients of mobility and diffusion. For the case of lithium, the calculations start by determining the gerade and ungerade potential curves through which ionic lithium approaches ground lithium. Then, by considering the isotopic effects and nuclear spins, the elastic and charge-transfer cross sections are calculated for the case of 6Li+and7Li+ colliding with 6Li. Finally, the temperature-dependent diffusion and mobility coefficients are analyzed, and the results are contrasted with those obtained from literature. The main results of this work have been recently published in. This work has been realized within the frames of the CNEPRU Project D01120110036 of the Algerian Ministry of Higher Education.

  13. Diffusion of $^{6}$Li in Ta and W

    CERN Document Server

    Vacik, J

    2006-01-01

    The objective of this work was the study of 6Li diffusion in the Ta and W refractory metals. The samples were prepared by ion implantation of 380 keV 6Li+ ions into W and Ta thin foils (up to the fluence of 1016 ions/cm2) and annealed up to the temperature 1940 °C. The depth profiles of 6Li were determined using the Thermal Neutron Depth Profiling (TNDP) technique. The results showed that diffusion of 6Li in both W and Ta foils is very complex and cannot be described by simple Fick’s laws. Trapping centers (in the subsurface layers of both W and Ta metals) were supposed in a trial to explain the 6Li diffusion behaviour. However, the 6Li depth profiles were only partly explained. Other aspects are necessary to take into account for more proper quantification; such as spatially dependent diffusion coefficients, etc.

  14. 6^Li in the atmosphere of GJ 117

    CERN Document Server

    Christian, D J; Jevremovic, D; Hauschildt, P H; Baron, E

    2005-01-01

    We present high resolution VLT UVES observations of the active K dwarf GJ 117. 6^Li enhancement has been shown for energetic solar events, one chromospherically active binary, and several dwarf halo stars. Our analysis reveals the detection of 6^Li on this source with 6^Li/7^Li = 0.030+/-0.010. We found no significant contribution from other lines, including Ti I, in the Li profile of GJ 117 and a template star of similar spectral type and metallicity. We discuss the possibility for 6^Li production by spallation and find it to be consistent with the activity levels of the object.

  15. Four-body dynamics in 6Li elastic scattering

    CERN Document Server

    Watanabe, Shin; Ogata, Kazuyuki; Yahiro, Masanobu

    2015-01-01

    We analyze 6Li elastic scattering in a wide range of incident energies (Ein), assuming the n + p + alpha + target four-body model and solving the dynamics with the four-body version of the continuum-discretized coupled-channels method (CDCC). Four-body CDCC well reproduces the experimental data with no adjustable parameter for 6Li + 209Bi scattering at Ein = 24-50 MeV and 6Li + 208Pb scattering at Ein = 29-210 MeV. In the wide Ein range, 6Li breakup is significant and provides repulsive corrections to the folding potential. As an interesting property, d breakup is strongly suppressed in 6Li-breakup processes independently of Ein. We investigate what causes the d-breakup suppression.

  16. Big Bang 6Li nucleosynthesis studied deep underground (LUNA collaboration)

    Science.gov (United States)

    Trezzi, D.; Anders, M.; Aliotta, M.; Bellini, A.; Bemmerer, D.; Boeltzig, A.; Broggini, C.; Bruno, C. G.; Caciolli, A.; Cavanna, F.; Corvisiero, P.; Costantini, H.; Davinson, T.; Depalo, R.; Elekes, Z.; Erhard, M.; Ferraro, F.; Formicola, A.; Fülop, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Junker, M.; Lemut, A.; Marta, M.; Mazzocchi, C.; Menegazzo, R.; Mossa, V.; Pantaleo, F.; Prati, P.; Rossi Alvarez, C.; Scott, D. A.; Somorjai, E.; Straniero, O.; Szücs, T.; Takacs, M.

    2017-03-01

    The correct prediction of the abundances of the light nuclides produced during the epoch of Big Bang Nucleosynthesis (BBN) is one of the main topics of modern cosmology. For many of the nuclear reactions that are relevant for this epoch, direct experimental cross section data are available, ushering the so-called "age of precision". The present work addresses an exception to this current status: the 2H(α,γ)6Li reaction that controls 6Li production in the Big Bang. Recent controversial observations of 6Li in metal-poor stars have heightened the interest in understanding primordial 6Li production. If confirmed, these observations would lead to a second cosmological lithium problem, in addition to the well-known 7Li problem. In the present work, the direct experimental cross section data on 2H(α,γ)6Li in the BBN energy range are reported. The measurement has been performed deep underground at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in the Laboratori Nazionali del Gran Sasso, Italy. The cross section has been directly measured at the energies of interest for Big Bang Nucleosynthesis for the first time, at Ecm = 80, 93, 120, and 133 keV. Based on the new data, the 2H(α,γ)6Li thermonuclear reaction rate has been derived. Our rate is even lower than previously reported, thus increasing the discrepancy between predicted Big Bang 6Li abundance and the amount of primordial 6Li inferred from observations.

  17. Model Calculation of n + 6Li Reactions Below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang; HAN Yin-Lu

    2001-01-01

    Based on the unified Hauser-Feshbach and exciton model for light nuclei, the calculations of reaction cross sections and the double-differential cross sections for n + 6Li are performed. Since all of the first-particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism must be taken into account. The fitting of the measured data indicates that the three-body break-up process needs to be involved, and the pre-equilibrium reaction mechanism dominates the reaction processes. In light nucleus reactions the recoil effect must be taken into account.``

  18. Buffer-gas-assisted polarization spectroscopy of 6Li.

    Science.gov (United States)

    Ohtsubo, Nozomi; Aoki, Takatoshi; Torii, Yoshio

    2012-07-15

    We report on the demonstration of Doppler-free polarization spectroscopy of the D2 line of (6)Li atoms. Counterintuitively, the presence of an Ar buffer gas, in a certain pressure range, causes a drastic enhancement of the polarization rotation signal. The observed dependence of the signal amplitude on the Ar buffer pressure and the pump laser power is reproduced by calculations based on simple rate equations. We performed stable laser frequency locking using a dispersion signal obtained by polarization spectroscopy for laser cooling of (6)Li atoms.

  19. Reaction mechanisms in the 6Li+ 52Cr system

    Directory of Open Access Journals (Sweden)

    Pandey Bhawna

    2015-01-01

    Full Text Available Reactions induced by the weakly bound 6Li projectile interacting with the intermediate mass target 52Cr are investigated. The choice of this particular reaction in our study is because it is proposed as a surrogate reaction [6Li(52Cr, d56Fe*] for the measurement of 55Fe(n,p reaction cross-section, which has been found to be very important in fusion reactor studies. All the conditions which have to be satisfied for using the surrogate method have been checked. The energy of 6Li beam is selected in a way so as to get equivalent neutron energy in the region of 9-14 MeV, which is of primary interest in fusion reactor application. In the present work, statistical model calculations PACE (Projection-Angular-Momentum-Coupled-Evaporation, ALICE and Continuum-Discretized–Coupled-Channel (CDCC: FRESCO have been used to provide information for the 6Li + 52Cr system and the respective contributions of different reaction mechanisms. The present theoretical work is an important step in the direction towards studying the cross-section of the 55Fe(n, p55Mn reaction by surrogate method.

  20. Disappearance of Mott oscillations in sub-barrier elastic scattering of identical nuclei and atomic ions

    CERN Document Server

    Hussein, M S; Donangelo, R; Mittig, W

    2015-01-01

    The scattering of identical nuclei at low energies exhibits conspicuous Mott oscillations which can be used to investigate the presence of components in the predominantly Coulomb interaction arising from several physical effects. It is found that at a certain critical value of the Sommerfeld parameter the Mott oscillations disappear and the cross section becomes quite flat. We call this effect Transverse Isotropy (TI). The critical value of the Sommerfeld parameter at which TI sets in is found to be $\\eta_{c} = \\sqrt{3s +2}$, where $s$ is the spin of the nuclei participating in the scattering. No TI is found in the Mott scattering of identical Fermionic nuclei. The critical center of mass energy corresponding to $\\eta_c$ is found to be $E_c$ = 0.40 MeV for $\\alpha + \\alpha$ (s = 0) , 1.2 MeV for $^{6}$Li + $^{6}$LI (s = 1) and 7.1 MeV for $^{10}$B + $^{10}$B (s = 3). We further found that the inclusion of the nuclear interaction induces a significant modification in the TI. We suggest measurements at these su...

  1. Unusual Threshold Anomaly in the 6Li+208Pb System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-Lei; JIA Hui-Ming; WU Zhen-Dong; XU Xin-Xing; BAI Chun-Lin; ZHANG Huan-Qiao; LIN Cheng-Jian; RUAN Ming; LIU Zu-Hua; YANG Feng; WU Xiu-Kun; ZHOU Ping; AN Guang-Peng

    2006-01-01

    @@ The angular distributions of elastic scattering for the 6Li +208Pb system have been measured at several energies around the Coulomb barrier. The parameters of optical potential are extracted by means of a phenomenological optical model analysis. It is found that the real and imaginal potentials show a pronounced energy dependence.The behaviour of the potential at the nearly especially sub-barrier energies in the 6Li+208Pb system is quite different from the results of some previous reports observed in other systems, such as 19 F +208 Pb and 16 O+208 Pb.This unusual threshold phenomenon indicates that breakup channel is strongly coupled with the elastic channel and has obvious effects on optical potential.

  2. Elastic and inelastic scattering of {sup 6}Li + {sup 18}O versus {sup 7}Li + {sup 18}O and {sup 6}Li + {sup 16}O

    Energy Technology Data Exchange (ETDEWEB)

    Rudchik, Adam T., E-mail: rudchik@kinr.kiev.ua [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kliczewski, Stanislaw [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland); Chercas, Kostyantyn A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kemper, Kirby W. [Physics Department, Florida State University, Tallahassee, FL 32306-4350 (United States); Koshchy, Evgeniy I. [Kharkiv National University, pl. Svobody 4, 61077 Kharkiv (Ukraine); Rusek, Krzysztof [National Centre for Nuclear Research, ul. Hoża 69, PL-00-681 Warsaw (Poland); Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Rudchik, Andryi A.; Mezhevych, Sergyi Yu.; Pirnak, Valeryi M. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Plujko, Volodymyr A. [Taras Shevchenko Kyiv National University, vul. Volodymyrs' ka 64, 01033 Kyiv (Ukraine); Ponkratenko, Oleg A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Choiński, Jaroslaw [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Czech, Bronislaw; Siudak, Regina; Szczurek, Antoni [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland); Stolarz, Anna [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Zelinskyi, Ruslan M. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine)

    2014-02-15

    Inverse kinematics scattering of {sup 18}O on {sup 6}Li at E{sub lab}({sup 18}O) = 114 MeV was measured to obtain elastic and inelastic scattering cross sections. In this way cross sections for excited states in {sup 6}Li and {sup 18}O were determined. The data were analyzed within the optical model and coupled reaction channel method. The {sup 6}Li + {sup 18}O optical potential as well as the {sup 6}Li and {sup 18}O deformation parameters were deduced. Contributions of different nuclear processes to the {sup 6}Li + {sup 18}O elastic and inelastic scattering were explored. The isotopic differences between the {sup 6,7}Li + {sup 18}O and {sup 6}Li + {sup 16,18}O potential parameters were determined.

  3. Coulomb Breakup of Nucleus 6 Li on Ion 208Pb

    OpenAIRE

    Irgaziev, B. F.; ERGASHBAEV, H. T.

    1998-01-01

    In the framework of the three-body approach the A(a,bc)A Coulomb breakup has been investigated. The three-body Coulomb dynamic is taken into account to derive the expression for the reaction matrix element. The mechanism of the breakup includes the direct process and the excitation of resonance state of the particle a. The calculation of the triple differential cross section of the 208Pb(6Li, a d)208Pb Coulomb dissociation have been performed in the energy region Ea d < 1MeV. Cal...

  4. Photoassociative creation of ultracold heteronuclear 6Li40K* molecules

    CERN Document Server

    Ridinger, Armin; Salez, Thomas; Fernandes, Diogo Rio; Bouloufa, Nadia; Dulieu, Olivier; Salomon, Christophe; Chevy, Frederic

    2011-01-01

    We investigate the formation of weakly bound, electronically excited, heteronuclear 6Li40K* molecules by single-photon photoassociation in a magneto-optical trap. We performed trap loss spectroscopy within a range of 325 GHz below the Li(2S_(1/2))+K(4P_(3/2)) and Li(2S_(1/2))+K(4P_(1/2)) asymptotic states and observed more than 60 resonances, which we identify as rovibrational levels of 7 of 8 attractive long-range molecular potentials. The long-range dispersion coefficients and rotational constants are derived. We find large molecule formation rates of up to ~3.5x10^7s^(-1), which are shown to be comparable to those for homonuclear 40K_2*. Using a theoretical model we infer decay rates to the deeply bound electronic ground-state vibrational level X^1\\Sigma^+(v'=3) of ~5x10^4s^(-1). Our results pave the way for the production of ultracold bosonic ground-state 6Li40K molecules which exhibit a large intrinsic permanent electric dipole moment.

  5. Three-body parameter for Efimov states in 6Li

    Science.gov (United States)

    Huang, Bo; O'Hara, Kenneth M.; Grimm, Rudolf; Hutson, Jeremy M.; Petrov, Dmitry S.

    2014-10-01

    We present a state-of-the-art reanalysis of experimental results on Efimov resonances in the three-fermion system of 6Li. We discuss different definitions of the three-body parameter (3BP) for Efimov states and adopt a definition that excludes effects due to deviations from universal scaling for low-lying states. We develop a finite-temperature model for the case of three distinguishable fermions and apply it to the excited-state Efimov resonance to obtain the most accurate determination to date of the 3BP in an atomic three-body system. Our analysis of ground-state Efimov resonances in the same system yields values for the three-body parameter that are consistent with the excited-state result. Recent work has suggested that the reduced 3BP for atomic systems is a near-universal quantity, almost independent of the particular atom involved. However, the value of the 3BP obtained for 6Li is significantly (˜20 % ) different from that previously obtained from the excited-state resonance in Cs. The difference between these values poses a challenge for theory.

  6. Role of neutron transfer processes on the 6Li+120Sn and 7Li+119Sn fusion reactions

    Directory of Open Access Journals (Sweden)

    Fisichella M.

    2015-01-01

    Full Text Available The results concerning the study of 6Li+120Sn and 7Li+119Sn systems are presented. These two sistems are characterised by very similar structures of the interacting nuclei and by different Q-value for one-and two- neutron transfer. Our aim is to disentangle the possible effects due to the different n-transfer Q-values, at sub-barriers energies, by comparing the two fusion excitation function. In these experiments the fusion cross section has been measured by using a stack activation technique. No particular differences in the two fusion excitation functions have been observed.

  7. Nucleon momentum distributions and elastic electron scattering form factors for some 1p-shell nuclei

    Indian Academy of Sciences (India)

    A K Hamoudi; M A Hasan; A R Ridha

    2012-05-01

    The nucleon momentum distributions (NMD) and elastic electron scattering form factors of the ground state for 1p-shell nuclei with = (such as 6Li, 10B, 12C and 14N nuclei) have been calculated in the framework of the coherent density fluctuation model (CDFM) and expressed in terms of the weight function $|f(x)|^2$. The weight function has been expressed in terms of nucleon density distribution (NDD) of the nuclei and determined from the theory and the experiment. The feature of the long-tail behaviour at high-momentum region of the NMDs has been obtained by both the theoretical and experimental weight functions. The experimental form factors $F(q)$ of all the considered nuclei are very well reproduced by the present calculations for all values of momentum transfer . It is found that the contributions of the quadrupole form factors $F_{C2}(q)$ in 10B and 14N nuclei, which are described by the undeformed p-shell model, are essential for obtaining a remarkable agreement between the theoretical and experimental form factors.

  8. Systematics of the breakup probability function for {sup 6}Li and {sup 7}Li projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Capurro, O.A., E-mail: capurro@tandar.cnea.gov.ar [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); Pacheco, A.J.; Arazi, A. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Carnelli, P.F.F. [CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Fernández Niello, J.O. [Laboratorio TANDAR, Comisión Nacional de Energía Atómica, Av. General Paz 1499, B1650KNA San Martín, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); and others

    2016-01-15

    Experimental non-capture breakup cross sections can be used to determine the probability of projectile and ejectile fragmentation in nuclear reactions involving weakly bound nuclei. Recently, the probability of both type of dissociations has been analyzed in nuclear reactions involving {sup 9}Be projectiles onto various heavy targets at sub-barrier energies. In the present work we extend this kind of systematic analysis to the case of {sup 6}Li and {sup 7}Li projectiles with the purpose of investigating general features of projectile-like breakup probabilities for reactions induced by stable weakly bound nuclei. For that purpose we have obtained the probabilities of projectile and ejectile breakup for a large number of systems, starting from a compilation of the corresponding reported non-capture breakup cross sections. We parametrize the results in accordance with the previous studies for the case of beryllium projectiles, and we discuss their systematic behavior as a function of the projectile, the target mass and the reaction Q-value.

  9. Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion

    CERN Document Server

    Artemenkov, D A; Zarubin, P I

    2016-01-01

    A role of the unstable nuclei ${}^{6}$Be, ${}^{8}$Be and ${}^{9}$B in the dissociation of relativistic nuclei ${}^{7,9}$Be, ${}^{10}$B and ${}^{10,11}$C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration ${}^{6}$Be + $\\mit{n}$ to the ${}^{7}$Be nucleus structure is 8 $\\pm$ 1% which is near the value for the configuration ${}^{6}$Li + $\\mit{p}$. Distributions over the opening angle of $\\alpha$-particle pairs indicate to a simultaneous presence of virtual ${}^{8}$Be$_{g.s.}$ and ${}^{8}$Be$_{2^+}$ states in the ground states of the ${}^{9}$Be and ${}^{10}$C nuclei. The core ${}^{9}$B is manifested in the {${}^{10}$C} nucleus with a probability of 30 $\\pm$ 4%. Selection of the ${}^{10}$C "white" stars accompanied by ${}^{8}$Be$_{g.s.}$ (${}^{9}$B) leads to appearance in the excitation energy distribution of 2$\\alpha$2$\\mit{p}$ "quartets" of the distinct peak with a maximum at 4.1 $\\pm$ 0.3 MeV. ${}^{8}$Be$_{g.s.}$ decays are p...

  10. Efimov Physics in a 6Li-133Cs Atomic Mixture

    Science.gov (United States)

    Johansen, Jacob; Feng, Lei; Parker, Colin; Chin, Cheng; Wang, Yujun

    2015-05-01

    We investigate Efimov physics based on three-body recombination in an atomic mixture of 6Li and 133Cs in the vicinity of interspecies Feshbach resonances at 843 and 889 G. This allows us to compare the loss spectra near different resonances and test the universality of Efimov states. Theoretically the Efimov spectrum near 889 G is expected to be similar to that near 843 G, except that the first resonance is absent near the former Feshbach resonance. This is due to the difference in the Cs-Cs scattering length near the two resonances: At 843 G it is negative, whereas at 889 G it is positive. Although it is primarily the Li-Cs interactions that lead to Efimov resonances, the Cs-Cs scattering length is expected to influence the spectrum. This work is supported by NSF and Chicago MRSEC.

  11. Theoretical calculations and analysis for n + 6Li reaction

    Science.gov (United States)

    Tao, Xi; Wang, Jimin; Chen, Guochang; Shen, Qingbiao

    2017-09-01

    R-matrix theory is an important methodology for applications on light, medium and heavy mass nuclides nuclear reaction in the resonance energy range. Full R-matrix formalism contains the diagonal elements of the energy levels matrix and it is a rigorous theory. Because of different assumptions and approximations, many kinds of R-matrix derived methods are obtained. The new R-matrix code FDRR is presented and includes 4 kinds of R-matrix applications. It can be used for calculating integral cross sections and angular distributions of 2-bodies reactions. The cross sections and angular distributions of n+ 6Li reaction are calculated and analyzed by FDRR code. The results are in good agreement with experimental data below 20 MeV.

  12. High-energy break-up of 6Li as a tool to study the Big-Bang nucleosynthesis reaction 2H(alpha,gamma)6Li

    CERN Document Server

    Hammache, F; Typel, S; Galaviz, D; Sümmerer, K; Coc, A; Uhlig, F; Attallah, F; Caamano, M; Cortina, D; Geissel, H; Hellström, M; Iwasa, N; Kiener, J; Koczon, P; Kohlmeyer, B; Mohr, P; Schwab, E; Schwarz, K; Schümann, F; Senger, P; Sorlin, O; Tatischeff, V; Thibaud, J P; Vangioni, E; Wagner, A; Walus, W

    2010-01-01

    The recently claimed observations of non-negligible amounts of 6Li in old halo stars have renewed interest in the Big-Bang Nucleosynthesis (BBN) of 6Li. One important ingredient in the predicted BBN abundance of 6Li is the low-energy 2H(alpha,gamma)6Li cross section. Up to now, the only available experimental result for this cross section showed an almost constant astrophysical S-factor below 400 keV, contrary to theoretical expectations. We report on a new measurement of the 2H(alpha,gamma)6Li reaction using the break-up of 6Li at 150 A MeV. Even though we cannot separate experimentally the Coulomb contribution from the nuclear one, we find clear evidence for Coulomb-nuclear interference by analyzing the scattering-angular distributions. This is in-line with our theoretical description which indicates a drop of the S_24-factor at low energies as predicted also by most other models. Consequently, we find even lower upper limits for the calculated primordial 6Li abundance than before.

  13. THE 2H(alpha, gamma6LI REACTION AT LUNA AND BIG BANG NUCLEOSYNTHETIS

    Directory of Open Access Journals (Sweden)

    Carlo Gustavino

    2013-12-01

    Full Text Available The 2H(α, γ6Li reaction is the leading process for the production of 6Li in standard Big Bang Nucleosynthesis. Recent observations of lithium abundance in metal-poor halo stars suggest that there might be a 6Li plateau, similar to the well-known Spite plateau of 7Li. This calls for a re-investigation of the standard production channel for 6Li. As the 2H(α, γ6Li cross section drops steeply at low energy, it has never before been studied directly at Big Bang energies. For the first time the reaction has been studied directly at Big Bang energies at the LUNA accelerator. The preliminary data and their implications for Big Bang nucleosynthesis and the purported 6Li problem will be shown.

  14. All-optical production of 6Li quantum gases

    Science.gov (United States)

    Burchianti, A.; Seman, J. A.; Valtolina, G.; Morales, A.; Inguscio, M.; Zaccanti, M.; Roati, G.

    2015-03-01

    We report efficient production of quantum gases of 6Li using a sub-Doppler cooling scheme based on the D1 transition. After loading in a standard magneto-optical trap, an atomic sample of 109 atoms is cooled at a temperature of 40 μK by a bichromatic D1 gray-molasses. More than 2×107 atoms are then transferred into a high-intensity optical dipole trap, where a two-spin state mixture is evaporatively cooled down to quantum degeneracy. We observe that D1 cooling remains effective in the deep trapping potential, allowing an effective increase of the atomic phase-space density before starting the evaporation. In a total experimental cycle of 11 s, we produce weakly-interacting degenerate Fermi gases of 7×105 atoms at T/TF molecules. We further describe a simple and compact optical system both for high-resolution imaging and for imprinting a thin optical barrier on the atomic cloud; this represents a first step towards the study of quantum tunneling in strongly interacting superfluid Fermi gases.

  15. 6Li/7Li estimates for metal-poor stars

    CERN Document Server

    Perez, A E Garcia; Inoue, S; Ryan, S G; Suzuki, T K; Chiba, M

    2009-01-01

    The presence of the lithium-6 isotope in some metal-poor stars is a matter of surprise because of the high values observed. Non-standard models of Big Bang nucleosynthesis and pre-Galactic cosmic ray fusion and spallation have been proposed to explain these values. However, the observations of this light isotope are challenging which may make some detections disputable. The goal was to determine 6Li/7Li for a sample of metal-poor stars; three of them have been previously studied and the remaining two are new for this type of study. The purpose was to increase, if possible, the number of lithium-6 detections and to confirm previously published results. Spectra of the resonance doublet line of neutral lithium Li I 670.78nm were taken with the High Dispersion Spectrograph at the Subaru 8.2m-telescope for a sample of five metal-poor stars (-3.12 < [Fe/H] < -2.19). The contribution of lithium-6 to the total observed line profile was estimated from the 1D-LTE analysis of the line asymmetry. Observed asymmetri...

  16. $\\Sigma^- p$ emission rates in $K^-$ absorptions at rest on $^6$Li, $^7$Li, $^{9}$Be, $^{13}$C and $^{16}$O

    CERN Document Server

    Agnello, M; Bertani, M; Bonomi, G; Botta, E; Bregant, M; Bressani, T; Bufalino, S; Busso, L; Calvo, D; Camerini, P; Dalena, B; De Mori, F; D'Erasmo, G; Feliciello, A; Filippi, A; Fiore, E M; Fontana, A; Fujioka, H; Genova, P; Gianotti, P; Grion, N; Lucherini, V; Marcello, S; Morra, O; Nagae, T; Outa, H; Pantaleo, A; Paticchio, V; Piano, S; Rui, R; Simonetti, G; Wheadon, R; Zenoni, A

    2015-01-01

    An experimental study of the $K^-_{stop}A\\rightarrow \\Sigma^- p A'$ reaction on $A=^6$Li, $^7$Li, $^9$Be, $^{13}$C and $^{16}$O $p$-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DA$\\Phi$NE $\\phi$-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a $(np)$ pair embedded in the $A$ nucleus can be obtained from the study of the missing mass distributions.

  17. Effects of t- and α-transfer on the spectroscopic information from the {sup 6}Li({sup 3}He,d){sup 7}Be reaction

    Energy Technology Data Exchange (ETDEWEB)

    Burtebayev, N., E-mail: nburtebayev@yandex.ru [Institute of Nuclear Physics of National Nuclear Center, 480082, Almaty, Ibragimova str. 1 (Kazakhstan); Burtebayeva, J.T.; Glushchenko, N.V.; Kerimkulov, Zh.K. [Institute of Nuclear Physics of National Nuclear Center, 480082, Almaty, Ibragimova str. 1 (Kazakhstan); Amar, A. [Al-Farabi Kazakh National University, 480078, Almaty, al-Farabi ave. 71 (Kazakhstan); Tanta University, Faculty of Science, Physics Department, Tanta (Egypt); Nassurlla, M. [Al-Farabi Kazakh National University, 480078, Almaty, al-Farabi ave. 71 (Kazakhstan); Sakuta, S.B. [National Research Center “Kurchatov Institute”, Kurchatov Sq. 1, 123182 Moscow (Russian Federation); Artemov, S.V.; Igamov, S.B.; Karakhodzhaev, A.A. [Institute of Nuclear Physics, Tashkent, Avliyo Ota str. 61 (Uzbekistan); Rusek, K. [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Kliczewski, S. [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland)

    2013-07-01

    Angular distributions of differential cross sections have been measured for elastic, inelastic scattering and the ({sup 3}He,d) reaction on {sup 6}Li nuclei at the E{sub lab}({sup 3}He)=34 MeV energy. The new and early obtained elastic scattering data at 34, 50, 60 and 72 MeV have been analyzed with Coupled Reaction Channels Method (CRC) taking into account triton transfer mechanism. The spectroscopic factors for t+{sup 3}He configuration of {sup 6}Li were extracted. Parameters for real part of potential have been also calculated microscopically with double folding model. The differential cross sections for proton stripping to the {sup 7}Be ground and first excited states have been analyzed by modified DWBA and CRC methods at 34 MeV. The effect of triton and α exchange on proton transfer reaction {sup 6}Li({sup 3}He,d){sup 7}Be for both ground and excited state is discussed. Spectroscopic factors and asymptotical normalization coefficients for p+{sup 6}Li configuration of {sup 7}Be have been obtained from the experimental data.

  18. {sup 6}Li foil scintillation sandwich thermal neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, K.D., E-mail: ianakiev@lanl.gov [Los Alamos National Laboratory, MS E540, Los Alamos, NM 87545 (United States); Swinhoe, M.T.; Favalli, A.; Chung, K.; MacArthur, D.W. [Los Alamos National Laboratory, MS E540, Los Alamos, NM 87545 (United States)

    2011-10-01

    Increasing needs for neutron detection and limited supply of {sup 3}He have led to the need for replacement neutron detection technology. This paper presents the design and initial results for a neutron detector ({sup 6}Li foil scintillator sandwich) that uses lithium metal foil to detect thermal neutrons. The reaction products, primarily triton, deposit most of their energy in thin scintillator films and create light pulses. Gamma rays can deposit only a small amount of energy in the thin films and so produce only very small light pulses. Lithium is preferable to boron in this application because triton escapes from lithium more easily than does the alpha particle from boron, allowing the use of thicker films and hence greater efficiency. In addition, triton has a higher light output in the scintillator than the boron alpha particle. Lithium metal is preferable to a lithium compound, such as lithium fluoride, because the number of tritons that escape from the metal is greater for the same amount of lithium. Monte Carlo simulations show that good efficiency values can be achieved with reasonably sized detectors, values that are greater than that of comparable {sup 3}He systems for portal monitors. In addition, simulations of a neutron coincidence counting concept show high counting efficiency and short die-away time (16 {mu}s), which imply better performance than that of the high-level neutron coincidence counter (HLNCC)-II. Initial experimental measurements on a prototype detector using alpha particles (having similar light output to the expected tritons) show good light collection and transport properties.

  19. Projectile-breakup-induced fission-fragment angular distributions in the 6Li+232Th reaction

    Science.gov (United States)

    Pal, A.; Santra, S.; Chattopadhyay, D.; Kundu, A.; Ramachandran, K.; Tripathi, R.; Roy, B. J.; Nag, T. N.; Sawant, Y.; Sarkar, D.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2017-08-01

    Background: Experimental anisotropy in fission-fragment (FF) angular distribution in reactions involving weakly bound stable projectiles with actinide targets are enhanced compared to statistical saddle-point model (SSPM) predictions. Contributions from breakup- or transfer-induced fission to total fission are cited as possible reasons for such enhancement. Purpose: To identify the breakup- or transfer-induced fission channels in 6Li+232Th reaction and to investigate their effects on FF angular anisotropy. Methods: The FF angular distributions have been measured exclusively at three beam energies (28, 32, and 36 MeV) around the Coulomb barrier in coincidence with projectile breakup fragments like α , d , and p using Si strip detectors. The angular anisotropy obtained for different exclusive breakup- or transfer-induced fission channels are compared with that for total fission. SSPM and pre-equilibrium fission models have been employed to obtain theoretical FF angular anisotropy. Results: Angular anisotropy of the fission fragments produced by different transfer- or breakup-induced fission reactions have been obtained separately in the rest frame of respective recoiling nuclei. Some of these anisotropies were found to be stronger than those of the inclusive fission. Overall angular distributions of transfer or breakup fission, integrated over all possible recoil angles with weight factor proportional to differential cross section of the complementary breakup fragment emitted in coincidence in all possible directions, were obtained. It was observed that the overall FF angular anisotropy for each of these fission channels is less than or equal to the anisotropy of total fission at all the measured energies. Assuming isotropic out-of-plane correlations between the fission fragments and light-charged particles, the overall breakup- or transfer-induced fission fragment angular distributions do not explain the observed enhancement in FF anisotropy of total fission. Pre

  20. Basic technology for 6Li enrichment using an ionic-liquid impregnated organic membrane

    Science.gov (United States)

    Hoshino, Tsuyoshi; Terai, Takayuki

    2011-10-01

    The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ( 6Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% 6Li. 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 6Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the 6Li isotope separation coefficient in this method (about 1.1-1.4) was larger than that in the mercury amalgam method (about 1.06).

  1. Search for the Halo Effect in the 1H(6He, 6Li)n Peaction

    Institute of Scientific and Technical Information of China (English)

    李志宏; 柳卫平; 白希祥; 王友宝; 连钢; 李志常; 申庆彪; 林承键; 曾晟; 符长波

    2002-01-01

    The angular distributions of the charge exchange reaction 1 H(6He, 6Li)n were measured in reverse kinematics with a secondary 6He beam at the energy of4.17 AMeV. The data were analysed in the context ora microscopic calculation. It is shown that both the ground state of6He and the second excited state of6Li (3.563 MeV, 0+) have a halo structure.

  2. 6LiF oleic acid capped nanoparticles entrapment in siloxanes for thermal neutron detection

    Science.gov (United States)

    Carturan, S.; Maggioni, G.; Marchi, T.; Gramegna, F.; Cinausero, M.; Quaranta, A.; Palma, M. Dalla

    2016-07-01

    The good light output of siloxane based scintillators as displayed under γ-rays and α particles has been exploited here to obtain clear and reliable response toward thermal neutrons. Sensitization towards thermal neutrons has been pursued by adding 6LiF, in form of nanoparticles. Aiming at the enhancement of compatibility between the inorganic nanoparticles and the low polarity, siloxane based surrounding medium, oleic acid-capped 6LiF nanoparticles have been synthesized by thermal decomposition of Li trifluoroacetate. Thin pellets siloxane scintillator maintained their optical transmittance up to weight load of 2% of 6Li. Thin samples with increasing 6Li concentration and thicker ones with fixed 6Li amount have been prepared and tested with several sources (α, γ-rays, moderated neutrons). Light output as high as 80% of EJ212 under α irradiation was measured with thin samples, and negligible changes have been observed as a result of 6LiF addition. In case of thick samples, severe light loss has been observed, as induced by opacity. Nevertheless, thermal neutrons detection has been assessed and the data have been compared with GS20, based on Li glass, taken as a reference material.

  3. Breakup coupling effects on near-barrier inelastic scattering of the weakly bound {sup 6}Li projectile on a {sup 144}Sm target

    Energy Technology Data Exchange (ETDEWEB)

    Woodard, A.E., E-mail: awoodard@nd.edu [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Figueira, J.M. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Otomar, D.R. [Instituto de Fisica, Universidade Federal Fluminense, Gragoata, Niteroi, R. J., 24210-340 (Brazil); Fernandez Niello, J.O. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, B1650BWA San Martin, Buenos Aires (Argentina); Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Gragoata, Niteroi, R. J., 24210-340 (Brazil)

    2012-01-01

    Angular distributions for the inelastic scattering of the weakly bound {sup 6}Li nucleus from a {sup 144}Sm target (associated with the contributions of both the 2{sub 1}{sup +} and 3{sub 1}{sup -144}Sm excited states together) were measured at bombarding energies close to the Coulomb barrier. The experimental data were compared with expected results based on continuum discretized coupled-channel (CDCC) calculations. The results confirm that it is essential to include continuum-continuum couplings to reproduce the experimental data. The analysis demonstrates that inelastic scattering data can be a critical tool in testing full CDCC calculations involving weakly bound nuclei.

  4. Determining the 6Li Doped Side of a Glass Scintillator for Ultra Cold Neutrons

    CERN Document Server

    Jamieson, Blair

    2015-01-01

    Ultracold neutron (UCN) detectors using two visually very similar, to the microscopic level, pieces of optically contacted Cerium doped lithium glasses have been proposed for high rate UCN experiments. The chief difference between the two glass scintillators is that one side is 6Li depleted and the other side Li doped. This note outlines a method to determine which side of the glass stack is doped with 6Li using AmBe and 252Cf neutron sources, and a Si surface barrier detector. The method sees an excess of events around the alpha and triton energies of neutron capture on 6Li when the enriched side is facing the Si surface barrier detector.

  5. Cosmic Ray Production of $^6$Li by Structure Formation Shocks in the Early Galaxy

    CERN Document Server

    Inoue, S; Inoue, Susumu; Suzuki, Takeru Ken

    2003-01-01

    We discuss the production of the element $^6$Li in the early Galaxy by cosmic rays accelerated at structure formation shocks, driven by the hierarchical merging of sub-Galactic halos during Galaxy formation. The salient features of this scenario are discussed and compared with observations of $^6$Li in metal-poor halo stars, including a recent Subaru HDS result on the star HD140283. Some unique predictions of the model are clearly testable by future observations and may also provide important insight into how the Galaxy formed.

  6. Properties of 4He and 6Li with improved chiral EFT interactions

    Directory of Open Access Journals (Sweden)

    Maris P.

    2016-01-01

    Full Text Available We present recent results for 4He and 6Li obtained with improved NN interactions derived from chiral effective field theory up to N4LO. The many-body calculations are performed order-by-order in the chiral expansion. At N3LO and N4LO additional renormalization using the Similarity Renormalization Group is adopted to improve numerical convergence of the many-body calculations. We discuss results for the ground state energies, as well as the magnetic moment and the low-lying spectrum of 6Li.

  7. Properties of 4He and 6Li with improved chiral EFT interactions

    Science.gov (United States)

    Maris, P.; Binder, S.; Calci, A.; Epelbaum, E.; Furnstahl, R. J.; Golak, J.; Hebeler, K.; Kamada, H.; Krebs, H.; Langhammer, J.; Liebig, S.; Meißner, U.-G.; Minossi, D.; Nogga, A.; Potter, H.; Roth, R.; Skibiński, R.; Topolnicki, K.; Vary, J. P.; Witala, H.

    2016-03-01

    We present recent results for 4He and 6Li obtained with improved NN interactions derived from chiral effective field theory up to N4LO. The many-body calculations are performed order-by-order in the chiral expansion. At N3LO and N4LO additional renormalization using the Similarity Renormalization Group is adopted to improve numerical convergence of the many-body calculations. We discuss results for the ground state energies, as well as the magnetic moment and the low-lying spectrum of 6Li.

  8. Quasi-bound alpha resonant states populated by the {sup 12}C({sup 6}Li, d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M.R.D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [Istituto Nazionale di Fisica Nucleare (LNS/INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculdade de Psicologia

    2012-07-01

    Full text: The alpha cluster phenomenon in the light nuclei structure has been the subject of a long time investigation since the proposal of the Ikeda diagrams [1]. The main purpose of the research program in progress is the investigation of this phenomenon in (x{alpha}) and (x{alpha}+n) nuclei through the ({sup 6}Li, d) alpha transfer reaction [2-4]. Alpha resonant states around the (4{alpha}) threshold in the nucleus {sup 16}O are the focus of the present contribution. In fact, the importance of these resonances at the elements production in stars is recognized, as primarily pointed out by Hoyle in {sup 12}C [6]. The existence of a rotational band with the {alpha} +{sup 12} C (Hoyle) cluster state structure was recently demonstrated by Ohkubo and Hirabayashi [6]. In order to explore this region of interest, measurements of the {sup 12}C({sup 6}Li, d){sup 16}O reaction up to 17 MeV of excitation at an incident energy of 25.5 MeV, have been performed employing the Sao Paulo Pelletron-Enge Split-Pole facility and the nuclear emulsion detection technique (plates Fuji G6B, 50 {mu}m thick). Spectra associated with six scattering angles, from 5 deg to 29 deg in the laboratory frame, each one 50 cm along the focal surface, were measured. Several narrow resonances with a quasi-bound behavior embedded in the continuum were detected and the resolution of 25 keV allowed for the separation of doublets not resolved before [7,8]. The absolute cross sections and the respective deuteron angular distributions were determined and the analysis is in progress. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl. E 68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978). [2] M.R.D.Rodrigues et al., in12th International Conference on Nuclear Reaction Mechanism, Varenna, Italy, edited by F. Cerutti and A. Ferrari , CERN Proceedings, 2010-2, pp. 331- 335. [3] T. Borello-Lewin et al., Proceedings of SOTANCP2, Brussels, Belgium 2010, edited by P. Descouvemount et al., Int. J

  9. Resonant, direct, and transfer breakup of 6Li by 112Sn

    Science.gov (United States)

    Chattopadhyay, D.; Santra, S.; Pal, A.; Kundu, A.; Ramachandran, K.; Tripathi, R.; Sarkar, D.; Sodaye, S.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2016-12-01

    Projectile breakup cross sections in the 6Li+112Sn reaction have been measured at two beam energies, 30 and 22 MeV. Cross sections for sequential breakup of 6Li into α +d via its resonant state of 1+ (5.65 MeV) in the continuum have been measured for the first time along with two other dominant resonant states of 3+ (2.18 MeV) and 2+ (4.31 MeV) at Ebeam=30 MeV. However, at 22 MeV, the α +d breakup is found to be only due to direct breakup process. Cross sections measured for sequential breakup via two transfer channels, (6Li,5Li ) and (6Li,8Be ), into α +p and α +α , respectively, and the above α +d breakup channels compared with the results of coupled-channels calculations unravel the reaction mechanisms involving a weakly bound projectile and different processes leading to large inclusive α -particle production.

  10. Hyperfine structure in photoassociative spectra of 6Li2 and 7Li2

    NARCIS (Netherlands)

    Abraham, E.R.I.; McAlexander, W.I.; Stoof, H.T.C.; Hulet, R.G.

    1996-01-01

    We present spectra of hyperfine resolved vibrational levels of the A1Σu+and 1 3Σg+ states of 6Li2 and 7Li2 obtained via photoassociation of colliding ultracold atoms in a magneto-optical trap. A simple first-order perturbation theory analysis accurately accounts for the frequency splittings and rela

  11. Basic technology for {sup 6}Li enrichment using an ionic-liquid impregnated organic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Tsuyoshi, E-mail: hoshino.tsuyoshi@jaea.go.jp [Blanket Irradiation and Analysis Group, Fusion Research and Development Directorate, Japan Atomic Energy Agency, 4002, Narita-cho, Oarai-machi, Higashi Ibaraki-gun, Ibaraki 311-1393 (Japan); Terai, Takayuki [The Institute of Engineering Innovation and Department of Nuclear Engineering and Management School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2011-10-01

    The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ({sup 6}Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% {sup 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 {sup 6}Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the {sup 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).

  12. A quantum degenerate Bose-Fermi mixture of 41K and 6Li

    Science.gov (United States)

    Wu, Yu-Ping; Yao, Xing-Can; Chen, Hao-Ze; Liu, Xiang-Pei; Wang, Xiao-Qiong; Chen, Yu-Ao; Pan, Jian-Wei

    2017-05-01

    We report a new apparatus for the study of two-species quantum degenerate mixture of 41K and 6Li atoms. We develop and combine several advanced cooling techniques to achieve both a large atom number and high phase space density of the two-species atom clouds. Furthermore, we build a high efficiency two-species magnetic transport system to transfer atom clouds from the 3D magneto-optical-trap chamber to a full glass science chamber of an extreme high vacuum environment and good optical access. We perform a forced radio-frequency evaporative cooling for 41K atoms while the 6Li atoms are sympathetically cooled in an optically plugged magnetic trap. Finally, we achieve the simultaneous quantum degeneracy for the 41K and 6Li atoms. The Bose-Einstein condensate of 41K has 1.4 × 105 atoms with a condensate fraction of about 62%, while the degenerate Fermi gas of 6Li has a total atom number of 5.4 × 105 at 0.25 Fermi temperature.

  13. VL51ES (Generation 6 Li-Ion Cell for Satellites

    Directory of Open Access Journals (Sweden)

    Defer M.

    2017-01-01

    Full Text Available This paper presents the design of Saft’s VL51ES (Generation 6 Li-Ion cell, the main challenges in the course of the development, the main BOL characteristics and performances achieved during the development program. Finally, it also describes how this cell fits in Saft’s battery range and the benefits of it.

  14. Gamow shell model description of radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li

    CERN Document Server

    Dong, G X; Fossez, K; Płoszajczak, M; Jaganathen, Y; Betan, R M Id

    2016-01-01

    According to standard stellar evolution, lithium abundance is believed to be a useful indicator of the stellar age. However, many evolved stars like red giants show huge fluctuations around expected theoretical abundances that are not yet fully understood. The better knowledge of nuclear reactions that contribute to the creation and destruction of lithium can help to solve this puzzle. In this work we apply the Gamow shell model (GSM) formulated in the coupled-channel representation (GSM-CC) to investigate the mirror radiative capture reactions $^6$Li$(p,\\gamma)$$^7$Be and $^6$Li$(n,\\gamma)$$^7$Li. The cross-sections are calculated using a translationally invariant Hamiltonian with the finite-range interaction which is adjusted to reproduce spectra, binding energies and one-nucleon separation energies in $^{6-7}$Li, $^7$Be. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states to the final bound states $J={3/2}_1^-$ and $J={1/2}^-$ of $^7$Li and $^7$Be are included. We demonstrate th...

  15. Nuclear reactions of the system {sup 6} Li on {sup 58} Ni near the Coulomb barrier; Reacciones nucleares del sistema {sup 6} Li sobre {sup 58} Ni cerca de la barrera de Coulomb

    Energy Technology Data Exchange (ETDEWEB)

    Lizcano, D.; Aguilera, E.F.; Garcia M, H.; Martinez Q, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Protons, alpha particles and deuterons coming from the reactions {sup 6} Li + {sup 58} Ni are detected to three different energy around the Coulomb barrier. The possible effects of the weakly bound character of the projectile are studied and the results are compared with previous data for the system {sup 6} Li + {sup 59} Co. (Author)

  16. Importance of $1n$-stripping process in the $^{6}$Li+$^{159}$Tb reaction

    CERN Document Server

    Pradhan, M K; Roy, Subinit; Basu, P; Goswami, A; Kshetri, R; Palit, R; Parkar, V V; Ray, M; Sarkar, M Saha; Santra, S

    2013-01-01

    The inclusive cross sections of the $\\alpha$-particles produced in the reaction $^{6}$Li+$^{159}$Tb have been measured at energies around the Coulomb barrier. The measured cross sections are found to be orders of magnitude larger than the calculated cross sections of $^{6}$Li breaking into $\\alpha$ and $d$ fragments, thus indicating contributions from other processes. The experimental cross sections of $1n$-stripping and $1n$-pickup processes have been determined from an entirely different measurement, reported earlier. Apart from incomplete fusion and/ $d$-transfer processes, the $1n$-stripping process is found to be a significant contributor to the inclusive $\\alpha$-particle cross sections in this reaction.

  17. Narrow-linewidth cooling of $^{6}$Li atoms using the 2S-3P transition

    CERN Document Server

    Chen, Hao-Ze; Wu, Yu-Ping; Liu, Xiang-Pei; Wang, Xiao-Qiong; Chen, Yu-Ao; Pan, Jian-Wei

    2016-01-01

    We report on a narrow-linewidth cooling of $^{6}$Li atoms using the $2S_{1/2}\\to 3P_{3/2}$ transition in the ultraviolet (UV) wavelength regime. By combining the traditional red magneto-optical trap (MOT) at 671 nm and the UV MOT at 323 nm, we obtain a cold sample of $1.3\\times10^9$ atoms with a temperature of 58 $\\mu$K. Furthermore, we demonstrate a high efficiency magnetic transport for $^{6}$Li atoms with the help of the UV MOT. Finally, we obtain $8.1\\times10^8$ atoms with a temperature of 296 $\\mu$K at a magnetic gradient of 198 G/cm in the science chamber with a good vacuum environment and large optical access.

  18. Scintillation properties of semiconducting 6LiInSe2 crystals to ionizing radiation

    Science.gov (United States)

    Wiggins, Brenden; Groza, Michael; Tupitsyn, Eugene; Lukosi, Eric; Stassun, Keivan; Burger, Arnold; Stowe, Ashley

    2015-11-01

    6LiInSe2 has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making 6LiInSe2 the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi4Ge3O12 (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  19. Optimization of a sup 6 LiF bolometric neutron detector

    CERN Document Server

    Silver, C S; Piccirillo, L; Timbie, P T; Zhou, J W

    2002-01-01

    The optimization of a sup 6 LiF bolometer for neutron spectroscopy applications has been accomplished with a series of 12 different detectors. This type of detector is similar to X-ray bolometers, which have been extensively studied, and the absorber has a high neutron capture cross-section. Each bolometer was irradiated with alpha particles to investigate its response to thermal pulses. The best resolution obtained with this series of bolometers was 39 keV FWHM at 5.3 MeV. One of the bolometers was calibrated with monoenergetic neutrons, and its thermal properties are derived from measurements over a range of temperatures. We discuss the considerations involved in optimizing a sup 6 LiF bolometer for different types of neutron applications.

  20. Autler-Townes splitting in two-color photoassociation of 6Li

    CERN Document Server

    Schloeder, U; Silber, C; Zimmermann, C; Schloeder, Ulrike; Deuschle, Thomas; Silber, Christian; Zimmermann, Claus

    2003-01-01

    We report on high-resolution two-color photoassociation spectroscopy in the triplet system of magneto-optically trapped 6Li. The absolute transition frequencies have been measured. Strong optical coupling of the bound molecular states has been observed as Autler-Townes splitting in the photoassociation signal. The spontaneous bound-bound transition rate is determined and the molecule formation rate is estimated. The observed lineshapes are in good agreement with the theoretical model.

  1. Formation of eta'(958) Meson Bound States by the 6Li(gamma,d) reaction

    CERN Document Server

    Miyatani, M; Nagahiro, H; Hirenzaki, S

    2016-01-01

    We have investigated the 6Li(gamma,d) reaction theoretically for the formation of the eta'(958) mesic nucleus close to the recoilless kinematics. We have developed the theoretical formula and reported the quantitative results of the formation spectra for various cases in this article. We have found that the formation cross sections are reduced by the effects of the fragile deuteron form factor.

  2. {sup 6}Li({sup 18}O, {sup 17}O){sup 7}Li reaction and comparison of {sup 6, 7}Li + {sup 16, 17, 18}O potentials

    Energy Technology Data Exchange (ETDEWEB)

    Rudchik, A.T., E-mail: rudchik@kinr.kiev.ua [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Chercas, K.A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kemper, K.W. [Physics Department, Florida State University, Tallahassee, FL 32306-4350 (United States); Rudchik, A.A. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Kliczewski, S. [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland); Koshchy, E.I. [Kharkiv National University, pl. Svobody 4, 61077 Kharkiv (Ukraine); Rusek, K. [National Center for Nuclear Reseaches, ul. Hoża 69, PL-00-681 Warsaw (Poland); Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Mezhevych, S.Yu.; Ponkratenko, O.A.; Pirnak, Val.M. [Institute for Nuclear Research, Ukrainian Academy of Sciences, Prospect Nauki 47, 03680 Kyiv (Ukraine); Plujko, V.A. [Taras Shevchenko National University, ul. Volodymyrska 64, 01033 Kyiv (Ukraine); Choiński, J. [Heavy Ion Laboratory of Warsaw University, ul. L. Pasteura 5A, PL-02-093 Warsaw (Poland); Czech, B.; Siudak, R.; Szczurek, A. [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland)

    2014-07-15

    Angular distributions of the {sup 6}Li({sup 18}O, {sup 17}O){sup 7}Li reaction were measured at E{sub lab}({sup 18}O)=114 MeV for ground and excited states of the exit channel nuclei for the first time. The data were analyzed within the coupled-reaction-channels method (CRC). The {sup 6}Li + {sup 18}O elastic and inelastic scattering channels as well as simplest one- and two-step reactions were included in the coupled-reaction-channels scheme. The {sup 7}Li + {sup 17}O potential was deduced by fitting CRC calculations to the reaction data. The spectroscopic amplitudes for single nucleon and nuclear cluster configurations were calculated within the translationally invariant shell model. Isotopic differences of the {sup 7}Li + {sup 16, 17, 18}O and {sup 7, 8}Li + {sup 17}O potentials and the reaction mechanisms were studied.

  3. Microscopic Model Analysis of the $^{6}He,^{6}Li$ + $^{28}Si$ Total Reaction Cross Sections at the Energy Range 5-50 a Mev

    CERN Document Server

    Lukyanov, K V; Lukyanov, V K; Penionzhkevich, Yu E; Sobolev, Y G; Zemlyanaya, E V; Penionzhkevich, Yu.E.; Sobolev, Yu.G.

    2007-01-01

    The existing and some preliminary experimental data on the total cross sections of the $^{4,6}$He, $^{6,7}$Li +$^{28}$Si reactions at energies E=5-50 A MeV are demonstrated. The data on $^{6}$Li,$^{6}$He+$^{28}$Si are analyzed in the framework of the microscopic optical potential with real and imaginary parts obtained with a help of the double-folding procedure and by using the current models of densities of the projectile nuclei. Besides, the microscopic double-folding Coulomb potential is calculated and its effect on cross sections is compared with that when one applies the traditional Coulomb potential of the uniform charge distribution. The semi-microscopic potentials are constructed from both the renormalized microscopic potentials and their derivatives to take into account collective motion effect and to improve an agreement with experimental data.

  4. KEPLER's First Rocky Planet: Kepler-10b

    CERN Document Server

    Batalha, Natalie M; Bryson, Stephen T; Buchhave, Lars A; Caldwell, Douglas A; Christensen-Dalsgaard, Jorgen; Ciardi, David; Dunham, Edward W; Fressin, Francois; Gautier, Thomas N; Gilliland, Ronald L; Haas, Michael R; Howell, Steve B; Jenkins, Jon M; Kjeldsen, Hans; Koch, David G; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Rowe, Jason F; Sasselov, Dimitar D; Seager, Sara; Steffen, Jason H; Torres, Guillermo; Basri, Gibor S; Brown, Timothy M; Charbonneau, David; Christiansen, Jessie; Clarke, Bruce; Cochran, William D; Dupree, Andrea; Fabrycky, Daniel C; Fischer, Debra; Ford, Eric B; Fortney, Jonathan; Girouard, Forrest R; Holman, Matthew J; Johnson, John; Isaacson, Howard; Klaus, Todd C; Machalek, Pavel; Moorehead, Althea V; Morehead, Robert C; Ragozzine, Darin; Tenenbaum, Peter; Twicken, Joseph; Quinn, Samuel; VanCleve, Jeffrey; Walkowicz, Lucianne M; Welsh, William F; Devore, Edna; Gould, Alan

    2011-01-01

    NASA's Kepler Mission uses transit photometry to determine the frequency of earth-size planets in or near the habitable zone of Sun-like stars. The mission reached a milestone toward meeting that goal: the discovery of its first rocky planet, Kepler-10b. Two distinct sets of transit events were detected: 1) a 152 +/- 4 ppm dimming lasting 1.811 +/- 0.024 hours with ephemeris T[BJD]=2454964.57375+N*0.837495 days and 2) a 376 +/- 9 ppm dimming lasting 6.86 +/- 0.07 hours with ephemeris T[BJD]=2454971.6761+N*45.29485 days. Statistical tests on the photometric and pixel flux time series established the viability of the planet candidates triggering ground-based follow-up observations. Forty precision Doppler measurements were used to confirm that the short-period transit event is due to a planetary companion. The parent star is bright enough for asteroseismic analysis. Photometry was collected at 1-minute cadence for >4 months from which we detected 19 distinct pulsation frequencies. Modeling the frequencies resul...

  5. Optimization of {sup 6}LiF:ZnS(Ag) Scintillator Light Yield Using Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Yehuda-Zada, Y. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ben-Gurion University (Israel); Pritchard, K.; Ziegler, J.B.; Cooksey, C.; Siebein, K. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Jackson, M.; Hurlbut, C. [Eljen Technology, Sweetwater Texas (United States); Kadmon, Y.; Cohen, Y.; Maliszewskyj, N.C. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ibberson, R.M.; Majkrzak, C.F. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Orion, Y. [Ben-Gurion University (Israel); Osovizky, A. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Rotem Industries Ltd, Rotem Industrial Park (Israel); University of Maryland (United States)

    2015-07-01

    Neutrons provide an effective tool to probe materials structure. Neutron diffraction is a method to determine the atomic and magnetic structure of a material based on neutron scattering. By this method a collimated incident beam of thermal neutrons heat the examined sample and based on the obtained diffraction pattern information on the structure of the material is provided. Research for developing a novel cold neutron detector for Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is underway at the NIST center for neutron research. The system unique design is aimed to provide over ten times fold faster analysis of materials than conventional system. In order to achieve the fast analysis a large number of neutron detectors is required. A key design constraint for this detector is the thickness of the neutron sensitive element. This is met using {sup 6}LiF:ZnS(Ag) scintillation material with embedded wavelength shifting (WLS) fibers conducting scintillation light to silicon photomultiplier photo-sensors. The detector sensitivity is determined by both the neutron capture probability ({sup 6}Li density) and the detectable light output produced by the ZnS(Ag) ionization, the latter of which is hindered by the fluorescence absorption of the scintillation light by the ZnS. Tradeoffs between the neutron capture probability, stimulated light production and light attenuation for determining the optimal stoichiometry of the {sup 6}LiF and ZnS(Ag) as well as the volume ratio of scintillator and fiber. Simulations performed using the GEANT4 Monte Carlo package were made in order to optimize the detector design. GEANT4 enables the investigation of the neutron interaction with the detector, the ionization process and the light transfer process following the nuclear process. The series of conversions required for this detector were modelled: - A cold neutron enters the sensor and is captured by {sup 6}Li in the scintillator mixture ({sup 6}Li (n,α) {sup 3}H

  6. {sup 6}Li breakup and suppression of complete fusion above the Coulomb barrier

    Energy Technology Data Exchange (ETDEWEB)

    Elmahdy, N.A. [Modern Academy for Engineering and Technology, Cairo (Egypt); Denikin, A.S. [Dubna International University, Dubna (Russian Federation); JINR, Flerov Laboratory of Nuclear Reactions, Dubna (Russian Federation); Ismail, M.; Ellithi, A.Y. [Cairo University, Cairo (Egypt)

    2015-05-15

    We study the role of the projectile breakup in the fusion process by example of the {sup 6}Li reactions with the {sup 59}Co, {sup 144}Sm and {sup 209}Bi targets in vicinity of the Coulomb barrier. The coupled channel and distorted wave approaches are employed in order to calculate the complete fusion and the breakup cross sections, respectively. The partial cross sections in both the channels are compared in order to estimate the breakup fraction responsible for the suppression of complete fusion. The calculations are compared with available experimental data. The conclusions and recommendations are made. (orig.)

  7. Characterization of the silicon+6LiF thermal neutron detection technique

    Science.gov (United States)

    Pappalardo, A.; Barbagallo, M.; Cosentino, L.; Marchetta, C.; Musumarra, A.; Scirè, C.; Scirè, S.; Vecchio, G.; Finocchiaro, P.

    2016-02-01

    The worldwide need to replace 3He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of 3He tubes.

  8. Characterization of the silicon+6LiF thermal neutron detection technique

    CERN Document Server

    Pappalardo, A; Cosentino, L; Marchetta, C; Musumarra, A; Scirè, C; Scirè, S; Vecchio, G; Finocchiaro, P

    2015-01-01

    The worldwide need to replace 3He for the neutron detection has triggered R&D on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to the one of 3He tubes.

  9. Comparative analysis of pulse shape discrimination methods in a {sup 6}Li loaded plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2015-07-11

    Three algorithms for discriminating between fast neutrons, thermal neutrons and gamma rays in a {sup 6}Li loaded plastic scintillator have been compared. Following a literature review of existing pulse shape discrimination techniques, the performance of the charge comparison method, triangular filtering and frequency gradient analysis were investigated in this work. The scintillator was exposed to three different mixed gamma/neutron radiation fields. The figure of merit of neutron/gamma separation was investigated over a broad energy range, as well as for the neutron capture energy region. After optimisation, all three methods were found to perform similarly in terms of neutron/gamma separation.

  10. Study of silicon+6LiF thermal neutron detectors: GEANT4 simulations versus real data

    Science.gov (United States)

    Meo, S. Lo; Cosentino, L.; Mazzone, A.; Bartolomei, P.; Finocchiaro, P.

    2017-09-01

    Research and development on alternative thermal neutron detection technologies and methods are nowadays needed as a possible replacement of 3He-based ones. Commercial solid state silicon detectors, coupled with neutron converter layers containing 6Li, have been proved to represent a viable solution for several applications as present in the literature. In order to better understand the detailed operation and the response and efficiency of such detectors, a series of dedicated GEANT4 simulations were performed and compared with real data collected in a few different configurations. The results show an excellent agreement between data and simulations, indicating that the behavior of the detector is fully understood.

  11. Characterization of the silicon+{sup 6}LiF thermal neutron detection technique

    Energy Technology Data Exchange (ETDEWEB)

    Pappalardo, A. [INFN Laboratori Nazionali del Sud, Catania (Italy); Barbagallo, M. [INFN Sezione di Bari (Italy); Cosentino, L.; Marchetta, C. [INFN Laboratori Nazionali del Sud, Catania (Italy); Musumarra, A. [INFN Laboratori Nazionali del Sud, Catania (Italy); Università di Catania (Italy); Scirè, C.; Scirè, S.; Vecchio, G.; Finocchiaro, P. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2016-02-21

    The worldwide need to replace {sup 3}He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing {sup 6}Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of {sup 3}He tubes.

  12. Astrophysical S factor for the radiative-capture reaction p{sup 6}Li {yields} {sup 7}Be{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Dubovichenko, S. B., E-mail: sergey@dubovichenko.ru [National Space Agency of the Republic of Kazakhstan, Fessenkov Astrophysical Institute, National Center of Space Research and Technology (Kazakhstan); Burtebaev, N., E-mail: burteb@inp.kz; Zazulin, D. M.; Kerimkulov, Zh. K. [National Nuclear Center of Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Amar, A. S. A. [Al-Farabi Kazakh National University (Kazakhstan)

    2011-07-15

    A new measurement of differential cross sections for elastic p{sup 6}Li 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{sup 6}Li interaction were constructed. Various experiments devoted to studying elastic p{sup 6}Li 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 {sup 6}Li at low energies was considered within the potential cluster model involving forbidden states.

  13. Pulse-Shape Analysis of Neutron-Induced Scintillation Light in Ni-doped 6LiF/ZnS

    Energy Technology Data Exchange (ETDEWEB)

    Cowles, Christian C.; Behling, Richard S.; Imel, G. R.; Kouzes, Richard T.; Lintereur, Azaree; Robinson, Sean M.; Stave, Sean C.; Siciliano, Edward R.; Wang, Zheming

    2016-10-06

    Abstract–Alternatives to 3He are being investigated for gamma-ray insensitive neutron detection applications, including plutonium assay. One promising material is lithium-6 fluoride with silver activated zinc sulfide 6LiF/ZnS(Ag) in conjunction with a wavelength shifting plastic. Doping the 6LiF/ZnS(Ag) with nickel (Ni) has been proposed as a means of reducing the decay time of neutron signal pulses. This research performed a pulse shape comparison between Ni-doped and non-doped 6LiF/ZnS(Ag) neutron pulses. The Ni-doped 6LiF/ZnS(Ag) had a 32.7% ± 0.3 increase in neutron pulse height and a 32.4% ± 0.3 decrease in neutron pulse time compared to the non-doped 6LiF/ZnS(Ag). Doping 6LiF/ZnS(Ag) with nickel may allow neutron detector operation with improved signal to noise ratios, and reduced pulse pileup affects, increasing the accuracy and range of source activities with which such a detector could operate.

  14. On the nuclear $(n;t)-$reaction in the three-electron ${}^{6}$Li atom

    CERN Document Server

    Frolov, Alexei M

    2012-01-01

    The nuclear $(n;t)-$reaction of the three-electron ${}^{6}$Li atom with thermal/slow neutrons is considered. An effective method has been developed for determining the probabilities of formation of various atoms and ions in different bound states. We discuss a number of fundamental questions directly related to numerical computations of the final state atomic probabilities. A few appropriate variational expansions for atomic wave functions of the incident lithium atom and final helium atom and/or tritium negatively charged ion are discussed. It appears that the final ${}^4$He atom arising during the nuclear $(n,{}^{6}$Li; ${}^4$He$,t)$-reaction in the three-electron Li atom can also be created in its triplet states. The formation of the quasi-stable three-electron $e^{-}_3$ during the nuclear $(n; t)-$reaction at the Li atom is briefly discussed. Bremsstrahlung emitted by atomic electrons accelerated by the rapidly moving fragments from this reaction is analyzed. The frequency spectrum of the emitted radiatio...

  15. Scintillation properties of semiconducting {sup 6}LiInSe{sub 2} crystals to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Brenden [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); Groza, Michael; Tupitsyn, Eugene [Fisk University, Nashville, TN (United States); Lukosi, Eric [University of Tennessee, Knoxville, TN (United States); Stassun, Keivan; Burger, Arnold [Vanderbilt University, Nashville, TN (United States); Fisk University, Nashville, TN (United States); Stowe, Ashley [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); University of Tennessee, Knoxville, TN (United States)

    2015-11-21

    {sup 6}LiInSe{sub 2} has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making {sup 6}LiInSe{sub 2} the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi{sub 4}Ge{sub 3}O{sub 12} (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  16. Optimizing ZnS/6LiF scintillators for wavelength-shifting-fiber neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Crow, Lowell [ORNL; Funk, Loren L [ORNL; Hannan, Bruce W [ORNL; Hodges, Jason P [ORNL; Riedel, Richard A [ORNL; Wang, Cai-Lin [ORNL

    2016-01-01

    In this paper we compare the performance of grooved and flat ZnS/6LiF scintillators in a wavelength shifting-fiber (WLSF) detector. Flat ZnS/6LiF scintillators with the thickness L=0.2-0.8 mm were characterized using photon counting and pulse-height analysis and compared to a grooved scintillator of approximately 0.8 mm thick. While a grooved scintillator considerably increases the apparent thickness of the scintillator to neutrons for a given coating thickness, we find that the flat scintillators perform better than the grooved scintillators in terms of both light yield and neutron detection efficiency. The flat 0.8-mm-thick scintillator has the highest light output, and it is 52% higher compared with a grooved scintillator of same thickness. The lower light output of the grooved scintillator as compared to the flat scintillator is consistent with the greater scintillator-WLSF separation and the much larger average emission angle of the grooved scintillator. We also find that the average light cone width, or photon travel-length as measured using time-of-flight powder diffraction of diamond and vanadium, decreases with increasing L in the range of L=0.6-0.8 mm. This result contrasts with the traditional Swank diffusion model for micro-composite scintillators, and could be explained by a decrease in photon diffusion-coefficient or an increase in micro-particle content in the flat scintillator matrix for the thicker scintillators.

  17. Line shift, line asymmetry, and the 6Li/7Li isotopic ratio determination

    CERN Document Server

    Cayrel, Roger; Chand, Hum; Bonifacio, Piercarlo; Spite, Monique; Spite, François; Petitjean, Patrick; Ludwig, Hans-Günter; Caffau, Elisabetta

    2007-01-01

    Context: Line asymmetries are generated by convective Doppler shifts in stellar atmospheres, especially in metal-poor stars, where convective motions penetrate to higher atmospheric levels. Such asymmetries are usually neglected in abundance analyses. The determination of the 6Li/7Li isotopic ratio is prone to suffering from such asymmetries, as the contribution of 6Li is a slight blending reinforcement of the red wing of each component of the corresponding 7Li line, with respect to its blue wing. Aims: The present paper studies the halo star HD 74000 and estimates the impact of convection-related asymmetries on the Li isotopic ratio determination. Method: Two methods are used to meet this aim. The first, which is purely empirical, consists in deriving a template profile from another element that can be assumed to originate in the same stellar atmospheric layers as Li I, producing absorption lines of approximately the same equivalent width as individual components of the 7Li I resonance line. The second metho...

  18. 17 CFR 260.10b-5 - Content.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Content. 260.10b-5 Section 260.10b-5 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rule Under Section 310 § 260.10b-5 Content. (a)...

  19. 17 CFR 260.10b-5 - Content.

    Science.gov (United States)

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Content. 260.10b-5 Section 260.10b-5 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rule Under Section 310 § 260.10b-5 Content. (a) Each...

  20. Fusion excitation function measurement for 6Li+64Ni at near-barrier energies

    Directory of Open Access Journals (Sweden)

    Shaikh Md. Moin

    2015-01-01

    Full Text Available Total fusion excitation function has been measured for the reaction of weakly bound 6Li projectile on medium mass 64Ni target at energies near the Coulomb barrier of the system. Online characteristic γ-ray detection method has been used to identify and determine the cross sections of the residues. No suppression of total fusion cross section (σTF is observed at above barrier energies. But enhancement of measured cross section with respect to the one-dimensional barrier penetration model (1-DBPM calculation is observed at below barrier energies. The enhancement can not be explained by coupled channels calculation with dominant projectile and target excitations as well as one-neutron stripping reaction.

  1. MeV Neutron Production from Thermal Neutron Capture in {6}^Li Simulated with Geant4

    CERN Document Server

    Santoro, Valentina; Bentley, Phillip M

    2015-01-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to $\\gamma$-ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for $^6$Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  2. Reaction mechanisms in the {sup 6}Li + {sup 59}Co system

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)], E-mail: fsouza@dfn.if.usp.br; Beck, C. [Institut Pluridisciplinaire Hubert Curien, UMR 7178, CNRS-IN2P3 et Universite Louis Pasteur, Boite Postale 28, F-67037 Strasbourg, Cedex 2 (France); Carlin, N. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Keeley, N. [CEA-Saclay DSM/IRFU/SPhN, F-91191 Gif sur Yvette Cedex (France); Neto, R. Liguori; Moura, M.M. de; Munhoz, M.G.; Del Santo, M.G.; Suaide, A.A.P.; Szanto, E.M.; Szanto de Toledo, A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil)

    2009-04-15

    The reactions induced by the weakly bound {sup 6}Li projectile interacting with the intermediate mass target {sup 59}Co were investigated. Light charged particles singles and {alpha}-d coincidence measurements were performed at the near barrier energies E{sub lab}=17.4, 21.5, 25.5 and 29.6 MeV. The main contributions of the different competing mechanisms are discussed. A statistical model analysis, Continuum-Discretized Coupled-Channels (CDCC) calculations and two-body kinematics were used as tools to provide information to disentangle the main components of these mechanisms. A significant contribution of the direct breakup was observed through the difference between the experimental sequential breakup cross section and the CDCC prediction for the non-capture breakup cross section.

  3. alpha. - d resonances and the low-lying states of sup 6 Li

    Energy Technology Data Exchange (ETDEWEB)

    Eskandarian, A.; Afnan, I.R. (School of Physical Sciences, The Flinders University of South Australia, Bedford Park, South Australia 5042 (Australia))

    1992-12-01

    The low-lying states (below the {sup 3}He-{sup 3}H threshold) of the {sup 6}Li nucleus are generated using three-body models with two-body nonlocal separable interactions between the constituent particles. The positions and widths of the states are determined by searching for the eigenvalues of the kernel of the Faddeev equations in the complex energy plane. When appropriate (for {ital T}=0 states only), the results are compared with a separate determination of these quantities from the {alpha}-{ital d} scattering process. All experimentally observed levels are found. Given that the Coulomb interaction is not included in our calculations, agreement with experiment is favorable for both the positions and the widths of the resonances.

  4. α-d resonances and the low-lying states of 6Li

    Science.gov (United States)

    Eskandarian, A.; Afnan, I. R.

    1992-12-01

    The low-lying states (below the 3-3H threshold) of the 6Li nucleus are generated using three-body models with two-body nonlocal separable interactions between the constituent particles. The positions and widths of the states are determined by searching for the eigenvalues of the kernel of the Faddeev equations in the complex energy plane. When appropriate (for T=0 states only), the results are compared with a separate determination of these quantities from the α-d scattering process. All experimentally observed levels are found. Given that the Coulomb interaction is not included in our calculations, agreement with experiment is favorable for both the positions and the widths of the resonances.

  5. Time-of-flight calibration of a 6Li glass epithermal neutron detector

    Science.gov (United States)

    Livingston; Saleh; Block; Brand

    2000-10-01

    The curing of Portland cement concrete involves the conversion of water from a free to a bound state. The process can be monitored nondestructively by measuring the shift in the neutron energy spectrum in the epithermal range (0.025-1 eV). A tuned array of 6Li glass detectors has been constructed with varying efficiencies over the epithermal energy range. To determine the efficiency of each detector as a function of neutron energy, it is necessary to calibrate it against a reference neutron spectrum. This was accomplished using a time-of-flight approach with a pulsed neutron beam produced at the Gaerttner LINAC Laboratory at Rensselaer Polytechnic Institute. With a neutron flight path of 25 m it was possible to determine the neutron detector efficiencies to an energy resolution of 11 microeV. The data showed good agreement with the detector design calculations.

  6. Thermal neutron detection by entrapping 6LiF nanocrystals in siloxane scintillators

    Science.gov (United States)

    Carturan, S. M.; Marchi, T.; Maggioni, G.; Gramegna, F.; Degerlier, M.; Cinausero, M.; Dalla Palma, M.; Quaranta, A.

    2015-06-01

    Exploiting the long experience in design and production of scintillating mixtures based on siloxane matrices with combinations of primary dye and waveshifter, a first set of 6LiF loaded scintillator disks has been produced. The synthesis is herein described and reported, as well as preliminary results on their light response towards thermal neutrons. The preservation of transparency and mechanical integrity of the scintillator material is challenging when introducing the inorganic salt LiF which is a "foreign body" to the organic polysiloxane host matrix Different strategies such as synthesis of nanoparticles and surface functionalization have been pursued to succeed in the entrapment of the neutron converter whilst maintaining moderate light output, optical transparency and flexibility of the base scintillator.

  7. MeV Neutron Production from Thermal Neutron Capture in 6Li Simulated With Geant4

    Science.gov (United States)

    Santoro, Valentina; DiJulio, Douglas D.; Bentley, Phillip M.

    2016-09-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to y- ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for 6 Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  8. Observation of repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms

    CERN Document Server

    Scazza, F; Massignan, P; Recati, A; Amico, A; Burchianti, A; Fort, C; Inguscio, M; Zaccanti, M; Roati, G

    2016-01-01

    We employ radio-frequency spectroscopy to investigate a polarized spin-mixture of ultracold ${}^6$Li atoms close to a broad Feshbach scattering resonance. Focusing on the regime of strong repulsive interactions, we observe well-defined coherent quasiparticles even for unitarity-limited interactions. We characterize the many-body system by extracting the key properties of repulsive Fermi polarons: the energy $E_+$, the effective mass $m^*$, the residue $Z$ and the decay rate $\\Gamma$. Above a critical interaction, $E_+$ is found to exceed the Fermi energy of the bath while $m^*$ diverges and even turns negative. Such findings reveal that the paramagnetic Fermi liquid state becomes thermodynamically unstable towards an energetically favored ferromagnetic phase.

  9. Investigation of α-cluster states in 13C via the (6Li,d) reaction

    CERN Document Server

    Rodrigues, M R D; Horodynski-Matsushigue, L B; Cunsolo, A; Cappuzzello, F; Duarte, J L M; Rodrigues, C L; Ukita, G M; Souza, M A; Miyake, H

    2010-01-01

    The 9Be(6Li,d)13C reaction was used to investigate possible α-cluster states in 13C. The reaction was measured at 25.5 MeV incident energy, employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. Ten out of sixteen known levels of 13C, up to 11 MeV of excitation, were observed and, due to the much improved energy resolution of 50 keV, at least three doublets could be resolved. This work presents a preliminary analysis of five of the most intensely populated states, also in comparison with the results of former transfer studies.

  10. Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

    Science.gov (United States)

    Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

    2016-07-01

    The recently developed Cs2LiYCl6:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6Li(n,α)t reaction while for the fast neutrons the 35Cl(n,p)35S and 35Cl(n,α)32P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9-3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7LiF target. We tested a CLYC detector 6Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  11. Fast neutron measurements with {sup 7}Li and {sup 6}Li enriched CLYC scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Giaz, A., E-mail: agnese.giaz@mi.infn.it [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Blasi, N.; Boiano, C.; Brambilla, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Camera, F. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Cattadori, C. [INFN sezione di Milano Bicocca, Piazza della Scienza 3, 20125 Milano (Italy); Ceruti, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Gramegna, F.; Marchi, T. [INFN Laboratori Nazionali di Legnaro, Viale dell’Università, 2, 35020 Legnaro, PD (Italy); Mattei, I. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Mentana, A. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Million, B.; Pellegri, L. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Rebai, M. [Università degli Studi di Milano Bicocca, Physics Department, Piazza della Scienza 3, 20126 Milano (Italy); Riboldi, S. [INFN Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Physics Department, Via Celoria 16, 20133 Milano (Italy); Salamida, F. [INFN sezione di Milano Bicocca, Piazza della Scienza 3, 20125 Milano (Italy); Tardocchi, M. [Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Via R. Cozzi 53, 2015 Milano (Italy)

    2016-07-21

    The recently developed Cs{sub 2}LiYCl{sub 6}:Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the {sup 6}Li(n,α)t reaction while for the fast neutrons the {sup 35}Cl(n,p){sup 35}S and {sup 35}Cl(n,α){sup 32}P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9–3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on {sup 35}Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a {sup 7}LiF target. We tested a CLYC detector {sup 6}Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector {sup 7}Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  12. Mth10b, a unique member of the Sac10b family, does not bind nucleic acid.

    Directory of Open Access Journals (Sweden)

    Yan-Feng Liu

    Full Text Available The Sac10b protein family is regarded as a group of nucleic acid-binding proteins that are highly conserved and widely distributed within archaea. All reported members of this family are basic proteins that exist as homodimers in solution and bind to DNA and/or RNA without apparent sequence specificity in vitro. Here, we reported a unique member of the family, Mth10b from Methanobacterium thermoautotrophicum ΔH, whose amino acid sequence shares high homology with other Sac10b family proteins. However, unlike those proteins, Mth10b is an acidic protein; its potential isoelectric point is only 4.56, which is inconsistent with the characteristics of a nucleic acid-binding protein. In this study, Mth10b was expressed in Escherichia coli and purified using a three-column chromatography purification procedure. Biochemical characterization indicated that Mth10b should be similar to typical Sac10b family proteins with respect to its secondary and tertiary structure and in its preferred oligomeric forms. However, an electrophoretic mobility shift analysis (EMSA showed that neither DNA nor RNA bound to Mth10b in vitro, indicating that either Mth10b likely has a physiological function that is distinct from those of other Sac10b family members or nucleic acid-binding ability may not be a fundamental factor to the actual function of the Sac10b family.

  13. The Astrophysical S-factor for the 2H(, )6Li Nuclear Reaction at Low-Energies

    Indian Academy of Sciences (India)

    H. Sadeghi; A. Moghadasi; M. Ghamary

    2014-12-01

    The alpha radiative capture reactions are the key to understand about primordial nucleosynthesis and the observed abundance of light nucleus in stars. The astrophysical S-factor for the process 2H(, )6Li has been calculated at the low-energies relevant to big-bang nucleosynthesis and in comparison with laboratory data. On the basis of the model, the alpha radiative capture process is studied by using the two-and three-body electromagnetic currents. The bound and resonance states of 6Li are calculated via an inverse process, deuteron- photodisintegration of a 6Li nucleus. In comparison with other theoretical approaches and available laboratory data, excellent agreement is achieved for the astrophysical S-factor of this process.

  14. Photoassociation spectroscopy of long-range molecular states below the 2s + 3p 6Li2 asymptote

    Science.gov (United States)

    Gross, Christian; Chaudhuri, Saptarishi; Gan, Jaren; Dieckmann, Kai

    2015-05-01

    We present photoassociation spectra of high-lying vibrational states of the interatomic potentials correlating to the 2s + 3p asymptote of 6Li2 . Starting from an atomic cloud in a magneto-optical trap we first drive a free-to-bound transition into a molecular bound state using a tunable ultra-violet laser. Thereafter we ionize these long-range molecules using a 532 nm laser and detect the resulting ions with a channeltron. We determine the absolute positions of the transitions with MHz precision utilizing a frequency comb based calibration. Lithium dimers are extensively studied theoretically using various models and methods. Spectroscopic measurements are crucial to test and benchmark these methods and are available for various electronic states and inter-nuclear distances of 6Li2 molecule. Our study provides the first experimental observation of long-range states of the 2s + 3p asymptote of 6Li2 .

  15. Tritium production in a sphere of /sup 6/LiD irradiated by 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Hemmendinger, A.; Ragan, C.E.; Shunk, E.R.; Ellis, A.N.; Anaya, J.M.; Wallace, J.M.

    1978-10-01

    The specific production of tritium in samples of /sup 6/LiH and /sup 7/LiH embedded in a 600-mm-diam sphere of /sup 6/LiD irradiated by a central source of 14-MeV neutrons was determined by measuring the activity of the hydrogen evolved from the samples of each isotope at each of five different radii in the /sup 6/LiD assembly. The entire process of decomposing the LiH, transferring the evolved gas into counters, and determining the decay rate was standardized by processing LiH samples irradiated by thermal neutrons for which the /sup 6/Li(n,..cap alpha..) cross section is well known. The specific production of tritium in /sup 6/LiH and /sup 7/LiH (embedded samples) and the activation of radiochemical detector foils of /sup 45/Sc, /sup 89/Y, /sup 90/Zr, /sup 169/Tm, /sup 191/Ir /sub 373/, /sup 193/Ir /sub 627/, /sup 197/Au, /sup 235/U, and /sup 238/U placed at various positions in the /sup 6/LiD sphere were calculated and compared with the experimental data. One- and three-dimensional Monte Carlo and S/sub n/ neutron-transport calculations were performed. The most reliable (three-dimensional Monte Carlo) calculation is in reasonable agreement with both the tritium-production and the radiochemical-activation data. The existing discrepancies between calculation and experiment appear largely attributable to uncertainties in some tritium-production and radiochemical-activation cross sections. 15 references.

  16. An atomic beam of 6Li — 7Li for high resolution spectroscopy from matrix isolation sublimation

    Science.gov (United States)

    Oliveira, A. N.; Sacramento, R. L.; Silva, B. A.; Uhlmann, F. O.; Wolff, W.; Cesar, C. L.

    2016-07-01

    We propose the Matrix Isolation Sublimation (MlSu) technique for generating cold lithium atoms for the measurement of the 6Li - 7Li isotope shift in D1 and D2 transitions. The technique is capable of generating cold 6Li and 7Li beams at 4 K with forward velocity of 125 m/s. Using this beam we offer a distinguished source of lithium atoms for transitions measurements, adding a new possibility to make high resolution spectroscopy towards improving the experimental checks of the theory.

  17. 6LiF Semiconductor Sandwich Spectrometer for Fast Neutron Spectrum Measurement%用于快中子能谱测量的6LiF夹心半导体谱仪

    Institute of Scientific and Technical Information of China (English)

    蒋勇; 李俊杰; 张涛; 范晓强; 郑春

    2012-01-01

    A detector of 6LiF semiconductor sandwich spectrometer was designed and manufactured. Characteristics of the spectrometer were tested in the fast neutron critical assembly. Measurement principle, configuration of detector and electronic circuit were introduced. Fast neutron spectrum was measured using the 6LiF semiconductor sandwich spectrometer. When the detector's 6 LiF mass thickness is 186 μg/cm2, the spectrometer's energy resolution is 363 keV in the thermal neutron field. For this spectrometer, the optimal fathomable neutron energy range is 0. 3-7. 5 MeV, and the background counts only take possession of 1 % in this area.%本文介绍了6 LiF夹心谱仪的测量原理、自行设计研制的6LiF夹心半导体谱仪探头结构及电子学系统组成等.在热中子场中测试了夹心谱仪的性能,获得了α粒子峰、T粒子峰及“和”峰在多道上的位置与能量分辨率,并用T粒子与“和”峰两个能量点的峰位对谱仪系统进行了能量刻度.分别用效应探头和本底探头测量了临界装置表面的效应谱和本底谱,当效应探头采用的6 LiF镀层质量厚度为186 μg/cm2时,6 LiF夹心谱仪对热中子的能量分辨率为363 keY,测量中子最佳能区为0.3~7.5 MeV,在该能区内,本底谱约占1%.

  18. Superheavy nuclei

    CERN Document Server

    Sáro, S

    2003-01-01

    Experiments leading to transuranium and far transuranium nuclei as far as element 106 (seaborgium) are described. Physical knowledge derived from experimental data at this stage of complete synthesis nuclear reactions since the 1980s is analyzed. The effect of the shell structure on the stability of the nuclei, the extra-push effect, and the effect of isospin are discussed. Experiments leading to the synthesis of nuclei with Z = 107 - 112 by cold fusion are also described, as are hot fusion reactions resulting in superheavy nuclei Z = 114, 116 where, however, confirmation is only pending. Current state of the art in this area is also highlighted

  19. Development of a 6LiF/ZnS-based Neutron Multiplicity Counter

    Energy Technology Data Exchange (ETDEWEB)

    Stave, Sean C.; Behling, Richard S.; Bernacki, Bruce E.; Bliss, Mary; Cowles, Christian C.; Kouzes, Richard T.; Lintereur, Azaree; Robinson, Sean M.; Siciliano, Edward R.

    2016-10-06

    Abstract–Neutron multiplicity counters are used in safeguards to provide rapid assay of samples which contain an unknown amount of plutonium in a potentially unknown configuration. A project at PNNL is using regular and nickel-quenched 6LiF/ZnS neutron-scintillator sheets and wavelength shifting plastic for light pipes in place of 3He. A combination of laboratory and modeling work predicts a LiF/ZnS-based system to be able to match or exceed the performance of the best 3He-based systems available. Also, the Ni-quenched material is expected to allow for improved neutron/gamma-ray discrimination at twice the event rate relative to the non-Ni-quenched LiF/ZnS. A new system based on the LiF/ZnS material is under construction and components are being used to optimize the detection efficiency and neutron/gamma-ray discrimination properties. Components of the new system are partially constructed and undergoing performance testing utilizing high-speed digitizers with field programmable gate arrays to perform the neutron/gamma-ray discrimination. The expected performance of the full-scale system is expected to be nearly the same as for 3He-based systems and is due for completion in 2016.

  20. A study of the proton spectra following the capture of $K^-$ in $^6$Li and $^{12}$C with FINUDA

    CERN Document Server

    Agnello, M; Benussi, L; Bertani, M; Bhang, H C; Bianco, S; Bonomi, G; Botta, E; Bregant, M; Bressani, Tullio; Bufalino, S; Busso, L; Calvo, D; Camerini, P; Cerello, P; Dalena, B; Mori, F D; D'Erasmo, G; Santo, D D; Elia, D; Fabbri, F L; Faso, D; Feliciello, A; Filippi, A; Filippini, V; Fini, R A; Fiore, E M; Fujioka, H; Gianotti, P; Grion, N; Hartmann, O; Krasnoperov, A V; Lenti, V; Lucherini, V; Manzari, V; Marcello, S; Maruta, T; Mirfakhraee, N; Morra, O; Nagae, T; Olin, A; Outa, H; Pace, E; Pallotta, M; Palomba, M; Pantaleo, A; Panzarasa, A; Paticchio, V; Piano, S; Pompili, F; Rui, R; Simonetti, G; Tereshchenko, V V; Tomassini, S; Toyoda, A; Wheadon, R; Zenoni, A

    2006-01-01

    Momenta spectra of protons emitted following the capture of $K^-$ in $^6$Li and $^{12}$C have been measured with 1% resolution. The $^{12}$C spectrum is smooth whereas for $^6$Li a well defined peak appears at about 500 MeV/$c$. The first observation of a structure in this region was identified as a strange tribaryon or, possibly, a $\\bar K$-nuclear state. The peak is correlated with a $\\pi^-$ coming from $\\Sigma^-$ decay in flight, selected by setting momenta larger than 275 MeV/$c$. The $\\Sigma^-$ could be produced, together with a 500 MeV/$c$ proton, by the capture of a $K^-$ in a deuteron-cluster substructure of the $^6$Li nucleus. The capture rate for such a reaction is $(1.62\\pm 0.23_{stat} ^{+0.71}_{-0.44}(sys))%/K^-_{stop}$, in agreement with the existing observations on $^4$He targets and with the hypothesis that the $^6$Li nucleus can be interpreted as a $(d+\\alpha)$ cluster.

  1. Probing Chiral Interactions in Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nogga, A; Barrett, B R; Meissner, U; Witala, H; Epelbaum, E; Kamada, H; Navratil, P; Glockle, W; Vary, J P

    2004-01-08

    Chiral two- and three-nucleon interactions are studied in a few-nucleon systems. We investigate the cut-off dependence and convergence with respect to the chiral expansion. It is pointed out that the spectra of light nuclei are sensitive to the three-nucleon force structure. As an example, we present calculations of the 1{sup +} and 3{sup +} states of {sup 6}Li using the no-core shell model approach. The results show contributions of the next-to-next-to-leading order terms to the spectra, which are not correlated to the three-nucleon binding energy prediction.

  2. Study of the 10B(p, αγ) 7Be and 10B (p,p‧ γ)10B reactions for PIGE purposes

    Science.gov (United States)

    Lagoyannis, A.; Preketes-Sigalas, K.; Axiotis, M.; Foteinou, V.; Harissopulos, S.; Kokkoris, M.; Misaelides, P.; Paneta, V.; Patronis, N.

    2015-01-01

    Differential cross sections were measured at 8 angles and at proton energies from 2 to 5 MeV for the 10B(p, αγ) 7Be and 10B (p,p‧ γ)10B reactions using two thin targets. The γ-rays emitted at Eγ = 429 and 718 keV respectively, were detected by four HPGe detectors placed on a motorized turntable. The overall systematic uncertainty of the measurements was estimated to be ∼8% while the statistical errors did not exceed 5%. The validity of the obtained cross sections was tested by performing a thick target benchmarking experiment. The results of the present work are compared with existing ones from literature and possible explanations for the observed differences are discussed.

  3. B cell activating factor (BAFF) selects IL-10(-)B cells over IL-10(+)B cells during inflammatory responses.

    Science.gov (United States)

    Ma, Ning; Zhang, Yu; Liu, Qilin; Wang, Zhiding; Liu, Xiaoling; Zhu, Gaizhi; Yu, Dandan; Han, Gencheng; Chen, Guojiang; Hou, Chunmei; Wang, Tianxiao; Ma, Yuanfang; Shen, Beifen; Li, Yan; Xiao, He; Wang, Renxi

    2017-02-12

    B cell activating factor (BAFF) regulates B cell maturation, survival, function, and plays a critical pathogenic role in autoimmune diseases. It remains unclear how BAFF affects IL-10(-)B cells versus regulatory B cells (Bregs) in inflammatory responses. In this study, we found that IL-10-expressing Bregs decreased in lupus-prone MRL/lpr mice and experimental allergic encephalomyelitis (EAE) mice. On blockade of the effects of BAFF with TACI-IgG, IL-10(+) Bregs were upregulated in MRL/lpr and EAE mice. In addition, BAFF expanded IL-10(+)B cells over IL-10(-)B cells under noninflammatory conditions in vitro, whereas it expanded IL-10(-)B cells over IL-10(+)B cells during inflammatory responses, such as stimulation with autoantigen and LPS. Finally, the selection of IL-10(-)B cells over IL-10(+)B cells by BAFF was dependent on BAFF receptors (BAFFR, TACI, and BCMA) that were upregulated by inflammatory responses. This study suggests that BAFF selects IL-10(-)B cells over IL-10(+) regulatory B cells via BAFF receptors in inflammatory responses.

  4. Towards {sup 6}Li-{sup 40}K ground state molecules

    Energy Technology Data Exchange (ETDEWEB)

    Brachmann, Johannes Felix Simon

    2013-02-08

    The production of a quantum gas with strong long - range dipolar interactions is a major scientific goal in the research field of ultracold gases. In their ro - vibrational ground state Li-K dimers possess a large permanent dipole moment, which could possibly be exploited for the realization of such a quantum gas. A production of these molecules can be achieved by the association of Li and K at a Feshbach resonance, followed by a coherent state transfer. In this thesis, detailed theoretical an experimental preparations to achieve state transfer by means of Stimulated Raman Adiabatic Passage (STIRAP) are described. The theoretical preparations focus on the selection of an electronically excited molecular state that is suitable for STIRAP transfer. In this context, molecular transition dipole moments for both transitions involved in STIRAP transfer are predicted for the first time. This is achieved by the calculation of Franck-Condon factors and a determination of the state in which the {sup 6}Li-{sup 40}K Feshbach molecules are produced. The calculations show that state transfer by use of a single STIRAP sequence is experimentally very well feasible. Further, the optical wavelengths that are needed to address the selected states are calculated. The high accuracy of the data will allow to carry out the molecular spectroscopy in a fast and efficient manner. Further, only a comparatively narrow wavelength tuneability of the spectroscopy lasers is needed. The most suitable Feshbach resonance for the production of {sup 6}Li-{sup 40}K molecules at experimentally manageable magnetic field strengths is occurring at 155 G. Experimentally, this resonance is investigated by means of cross-dimensional relaxation. The application of the technique at various magnetic field strengths in the vicinity of the 155 G Feshbach resonance allows a determination of the resonance position and width with so far unreached precision. This reveals the production of molecules on the atomic side

  5. Compounds of 6Li and natural Li for EPR dosimetry in photon/neutron mixed radiation fields.

    Science.gov (United States)

    Lund, E; Gustafsson, H; Danilczuk, M; Sastry, M D; Lund, A

    2004-05-01

    Formates and dithionates of 6Li, enriched and 7Li in natural composition of Li offer a possibility to measure the absorbed dose from photons and thermal neutrons in a mixed radiation field for instance at a boron neutron capture therapy (BNCT) facility. Tests with formates and dithionates of enriched 6Li and lithium compounds with natural composition have been performed at the BNCT facility at Studsvik, Sweden. Irradiations have been performed at 3 cm depth in a Perspex phantom in a fluence rate of thermal neutrons 1.8 x 10(9) n cm(-2) s(-1). The compounds were also irradiated in a pure X-ray field from a 4MV linear accelerator at 5 cm depth in a phantom with accurately determined absorbed doses. The signal intensity and shape was investigated within 3 h after the irradiation. A single line spectrum attributed to the CO2- radical was observed after irradiation of lithium formate. An increase in line width occurring after neutron irradiation in comparison with photon irradiation of the 6Li sample was attributed to dipolar broadening between CO2- radicals trapped in the tracks of the alpha particles. A spectrum due to the SO3- radical anion was observed after irradiation of lithium dithionate. The signal amplitude increased using the 6Li in place of the Li with natural composition of isotopes, in studies with low energy X-ray irradiation. Due to the decreased line width, caused by the difference in g(N) and I between the isotopes, the sensitivity with 6Li dithionate may be enhanced by an order of magnitude compared to alanine dosimetry. After comprehensive examination of the different combinations of compounds with different amounts of 6Li and 7Li regarding dosimetry, radiation chemistry and EPR properties these dosimeter material might be used for dose determinations at BNCT treatments and for biomedical experiments. Interesting properties of the radical formation might be visible due to the large difference in ionization density of neutrons compared to photons.

  6. Microanalysis system of ppm-order 10B concentrations in tissue for neutron capture therapy by prompt gamma-ray spectrometry

    Science.gov (United States)

    Kobayashi, Tooru; Kanda, Keiji

    1983-01-01

    For neutron capture therapy, a new technique for measuring 10B concentrations of ppm order in tissue has been developed by using 10B(n, α) 7Li ∗ prompt gamma-ray spectrometry. The measuring system consists of a Ge(Li) detector and a 6LiF tile neutron shield attached to the neutron guide tube of the Kyoto University Reactor (KUR) with very low background gamma-rays. The 10B concentrations of unknown samples were determined in comparison with gamma-ray data obtained from known samples. The detection limit of the system is 0.1-0.5 ppm 10B concentration. In the practical use of the system for neutron capture therapy, 10B concentrations of 10 ppm, which is ordinarily pre-injected into the tumor, can be measured in less than 30 s with 10% accuracy by using 1 g samples. Moreover, the system has the advantage that pre-treatment of the sample is not required. As a neutron monitor in a homogeneous sample, gamma-rays emitted from H(n, γ)D reactions are used. Therefore, neutron irradiation conditions of this system, i.e. fluence rate, energy spectrum, and distribution in the sample do not affect the analyzing results, and the quantity and dimensions of the sample are also not restricted.

  7. The locus of microRNA-10b

    Science.gov (United States)

    Biagioni, Francesca; Bossel Ben-Moshe, Noa; Fontemaggi, Giulia; Yarden, Yosef; Domany, Eytan; Blandino, Giovanni

    2013-01-01

    Contemporary microRNA research has led to significant advances in our understanding of the process of tumorigenesis. MicroRNAs participate in different events of a cancer cell’s life, through their ability to target hundreds of putative transcripts involved in almost every cellular function, including cell cycle, apoptosis, and differentiation. The relevance of these small molecules is even more evident in light of the emerging linkage between their expression and both prognosis and clinical outcome of many types of human cancers. This identifies microRNAs as potential therapeutic modifiers of cancer phenotypes. From this perspective, we overview here the miR-10b locus and its involvement in cancer, focusing on its role in the establishment (miR-10b*) and spreading (miR-10b) of breast cancer. We conclude that targeting the locus of microRNA 10b holds great potential for cancer treatment. PMID:23839045

  8. The Trojan-Horse Method applied to the {sup 6}Li(p,{alpha}){sup 3}He reaction down to astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Pappalardo, L.; Cherubini, S.; Del Zoppo, A.; La Cognata, M.; Musumarra, A.; Pellegriti, M.G.; Pizzone, R.G.; Rinollo, A.; Romano, S.; Typel, S

    2004-04-05

    The Trojan-Horse Method has been applied to the three-body d({sup 6}Li,{alpha}{sup 3}He)n break-up reaction in order to extract the bare nucleus S(E) factor for the {sup 6}Li(p,{alpha}){sup 3}He down to astrophysical energies.

  9. Theory of laser enhancement and suppression of cold reactions: the fermion-boson 6Li+7Li2(variant Planck's over 2pi omega0) 6Li7Li+7Li radiative collision.

    Science.gov (United States)

    Li, Xuan; Parker, Gregory A; Brumer, Paul; Thanopulos, Ioannis; Shapiro, Moshe

    2008-03-28

    We present a nonperturbative time-dependent quantum mechanical theory of the laser catalysis and control of a bifurcating A+BC(variant Planck's over 2pi omega(0))ABC*(v)(variant Planck's over 2pi omega(0) )AB+C reaction, with ABC*(v) denoting an intermediate, electronically excited, complex of ABC in the vth vibrational state. We apply this theory to the low collision energy fermion-boson light-induced exchange reaction, (6)Li((2)S)+(7)Li(2)((3)Sigma(u)(+))(variant Planck's over 2pi omega(0))((6)Li(7)Li(7)Li)*(variant Planck's over 2pi omega(0))(6)Li(7)Li((3)Sigma(+))+(7)Li((2)S). We show that at very low collision energies and energetically narrow (approximately 0.01 cm(-1)) initial reactant wave packets, it is possible to tune the yield of the exchange reaction from 0 to near-unity (yield >or=99%) values. Controllability is somewhat reduced at collisions involving energetically wider (approximately 1 cm(-1)) initial reactant wave packets. At these energetic bandwidths, the radiative reactive control, although still impressive, is limited to the 0%-76% reactive-probabilities range.

  10. Projectile breakup dynamics for {sup 6}Li+{sup 59}Co: Kinematical analysis of {alpha}-d coincidences

    Energy Technology Data Exchange (ETDEWEB)

    Souza, F.A.; Carlin, N.; Liguori Neto, R.; Siqueira-Mello, C.; Moura, M.M. de; Munhoz, M.G.; Oliveira, R.A.N.; Santo, M.G. del; Suaide, A.A.P.; Szanto, E.M.; Szanto de Toledo, A. [Instituto de Fisica - Universidade de Sao Paulo, Departamento de Fisica Nuclear, Sao Paulo, SP (Brazil); Beck, C. [CNRS-IN2P3 and Universite Louis Pasteur, Institut Pluridisciplinaire Hubert Curien, UMR 7178, Strasbourg (France); Keeley, N. [The Andrzej Soltan Institute for Nuclear Studies, Department of Nuclear Reactions, Warsaw (Poland); Diaz-Torres, A. [University of Surrey, Department of Physics, Faculty of Engineering and Physical Sciences, Guildford (United Kingdom)

    2010-05-15

    A study of the kinematics of the {alpha} -d coincidences in the {sup 6}Li+{sup 59}Co system at a bombarding energy of E{sub lab}=29.6 MeV is presented. With exclusive measurements performed over different angular intervals it is possible to identify the respective contributions of the sequential and direct projectile breakup components. The angular distributions of both breakup components are fairly well described by the Continuum-Discretized Coupled-Channels framework (CDCC). Furthermore, a careful analysis of these processes using a semiclassical approach provides information on both their lifetime and their distance of occurrence with respect to the target. Breakup to the low-lying (near-threshold) continuum is delayed, and happens at large internuclear distances. This suggests that the influence of the projectile breakup on the complete fusion process can be related essentially to the direct breakup to the {sup 6}Li high-lying continuum spectrum. (orig.)

  11. Comparison of Thermal Neutron Detection Efficiency of $^{6}$Li Scintillation Glass and $^{3}$He Gas Proportional Tube

    CERN Document Server

    Xu, Ming; Chen, Guo-Ming; Tao, Jun-Quan

    2013-01-01

    We report on a comparison study of the $^{3}$He gas proportional tube and the $^{6}$Li incorporated scintillation glasses on thermal neutron detection efficiency. Both $^{3}$He and $^{6}$Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source $^{252}$Cf and a paraffin moderator in an alignment system, we can get a small beam of thermal neutrons. A flash ADC is used to measure the thermal neutron spectrum of each detector, and the detected number of events is determined from the spectrum, then we can calculate the detection efficiency of different detectors. Meanwhile, the experiment have been modeled with GEANT4 to validate the results against the Monte Carlo simulation.

  12. Astrophysical S-factor for $^6$Li$(p,\\gamma)$$^7$Be in the coupled-channel Gamow shell model

    CERN Document Server

    Dong, G X; Michel, N; Płoszajczak, M

    2015-01-01

    We have applied the Gamow shell model (GSM) in the coupled-channel representation to study the astrophysical $S$-factor for the proton radiative capture reaction of $^6$Li. Reaction channels are built by coupling the proton wave function expanded in different partial waves with the GSM wave functions of the ground state ($1^+$) and the excited states ($3^+_1$, $0^+_1$ and $2^+_1$) of $^6$Li. All relevant $E1$, $M1$, and $E2$ transitions from the initial continuum states in $^7$Be to the final bound states (${3/2}^-_1$ and ${1/2}^-_1$) states are included. It is found that the calculated total astrophysical $S$ factor for this reaction agrees well with the experimental data.

  13. Integration of a $^6$LiInSe$_2$ Thermal Neutron Detector into a CubeSat Instrument

    CERN Document Server

    Egner, Joanna C; Burger, Arnold; Stassun, Keivan G; Buliga, Vladimir; Matei, Liviu; Bodnarik, Julia G; Stowe, Ashley C; Prettyman, Thomas H

    2016-01-01

    We present a preliminary design for a novel neutron detection system that is compact, lightweight, and low power consuming, utilizing the CubeSat platform making it suitable for space-based applications. This is made possible using the scintillating crystal lithium indium diselenide ($^6$LiInSe$_2$), the first crystal to include $^6$Li in the crystalline structure, and a silicon avalanche photodiode (Si-APD). The schematics of this instrument are presented as well as the response of the instrument to initial testing under alpha radiation. A principal aim of this work is to demonstrate the feasibility of such a neutron detection system within a CubeSat platform. The entire end-to-end system presented here is 10 cm x 10 cm x 15 cm, weighs 670 grams and requires 5 Volts direct current at 3 Watts.

  14. Study of the {sup 9}Be(p,{alpha}){sup 6}Li reaction via the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Romano, S.; Lamia, L.; Spitaleri, C.; Cherubini, S.; Gulino, M.; La Cognata, M.; Tumino, A. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); Li, C.; Pizzone, R.G. [INFN, Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method has been applied to the {sup 2}H({sup 9}Be,{sup 6}Li{alpha})n three-body reaction in order to investigate the {sup 9}Be(p,{alpha}){sup 6}Li two-body reaction, which is involved in the study of light element abundances (lithium, beryllium and boron). A coincidence measurement was performed in order to identify the presence of the quasi-free mechanism in the three-body reaction, needed for the application of the method. The astrophysical S(E)-factor was extracted and compared to direct data. No information about electron screening effects can be extracted due to the poor resolution of the indirect data. (orig.)

  15. Formation of η{sup '} (958) meson bound states by the {sup 6}Li(γ,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Miyatani, M.; Nagahiro, H.; Hirenzaki, S. [Nara Women' s University, Department of Physics, Nara (Japan); Ikeno, N. [Tottori University, Department of Regional Environment, Tottori (Japan)

    2016-07-15

    We have investigated the {sup 6}Li(γ,d) reaction theoretically for the formation of the η{sup '}(958) mesic nucleus close to the recoilless kinematics. We have developed the theoretical formula and reported the quantitative results of the formation spectra for various cases in this article. We have found that the formation cross sections are reduced by the effects of the fragile deuteron form factor. (orig.)

  16. Theoretical study of the α +d →6Li +γ astrophysical capture process in a three-body model

    Science.gov (United States)

    Tursunov, E. M.; Kadyrov, A. S.; Turakulov, S. A.; Bray, I.

    2016-07-01

    The astrophysical capture process α +d →6Li is studied in a three-body model. The initial state is factorized into the deuteron bound state and the (α +d )-scattering state. The final nucleus 6Li (1+) is described as a three-body bound state α +n +p in the hyperspherical Lagrange-mesh method. The contribution of the E 1 -transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E 1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E 2 -transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA Collaboration with the spectroscopic factor of 2.586 estimated from the bound-state wave functions of 6Li and a deuteron.

  17. Unified description of $^6$Li structure and deuterium-$^4$He dynamics with chiral two- and three-nucleon forces

    CERN Document Server

    Hupin, Guillaume; Navrátil, Petr

    2014-01-01

    Prototype for the study of weakly bound projectiles colliding on stable targets, the scattering of deuterium ($d$) on $^4$He ($\\alpha$) is an important milestone in the search for a fundamental understanding of low-energy reactions. At the same time, it is also important for its role in the Big-bang nucleosynthesis of $^6$Li and applications in the characterization of deuterium impurities in materials. We present the first unified {\\em ab initio} study of the $^6$Li ground state and $d$-$^4$He elastic scattering using two- and three-nucleon forces derived within the framework of chiral effective field theory. The six-nucleon bound-state and scattering observables are calculated by means of the no-core shell model with continuum. %and are compared to available experimental data. We analyze the influence of the dynamic polarization of the deuterium and of the chiral three-nucleon force, and examine the role of the continuum degrees of freedom in shaping the low-lying spectrum of $^6$Li. We find that the adopted...

  18. First direct measurement of the 2H(α,γ)6Li cross section at big bang energies and the primordial lithium problem.

    Science.gov (United States)

    Anders, M; Trezzi, D; Menegazzo, R; Aliotta, M; Bellini, A; Bemmerer, D; Broggini, C; Caciolli, A; Corvisiero, P; Costantini, H; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Prati, P; Rossi Alvarez, C; Scott, D A; Somorjai, E; Straniero, O; Szücs, T

    2014-07-25

    Recent observations of (6)Li in metal poor stars suggest a large production of this isotope during big bang nucleosynthesis (BBN). In standard BBN calculations, the (2)H(α,γ)(6)Li reaction dominates (6)Li production. This reaction has never been measured inside the BBN energy region because its cross section drops exponentially at low energy and because the electric dipole transition is strongly suppressed for the isoscalar particles (2)H and α at energies below the Coulomb barrier. Indirect measurements using the Coulomb dissociation of (6)Li only give upper limits owing to the dominance of nuclear breakup processes. Here, we report on the results of the first measurement of the (2)H(α,γ)(6)Li cross section at big bang energies. The experiment was performed deep underground at the LUNA 400 kV accelerator in Gran Sasso, Italy. The primordial (6)Li/(7)Li isotopic abundance ratio has been determined to be (1.5 ± 0.3) × 10(-5), from our experimental data and standard BBN theory. The much higher (6)Li/(7)Li values reported for halo stars will likely require a nonstandard physics explanation, as discussed in the literature.

  19. Absolute efficiency measurements with the 10B based Jalousie detector

    Science.gov (United States)

    Modzel, G.; Henske, M.; Houben, A.; Klein, M.; Köhli, M.; Lennert, P.; Meven, M.; Schmidt, C. J.; Schmidt, U.; Schweika, W.

    2014-04-01

    The 10B based Jalousie detector is a replacement for 3He counter tubes, which are nowadays less affordable for large area detectors due to the 3He crisis. In this paper we investigate and verify the performance of the new 10B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75-50% for neutron energies of 10-100 meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17 Å (59 meV).

  20. Production of secondary particles and nuclei in cosmic rays collisions with the interstellar gas using the FLUKA code

    CERN Document Server

    Mazziotta, M N; Ferrari, A; Gaggero, D; Loparco, F; Sala, P R

    2016-01-01

    The measured fluxes of secondary particles produced by the interactions of Cosmic Rays (CRs) with the astronomical environment play a crucial role in understanding the physics of CR transport. In this work we present a comprehensive calculation of the secondary hadron, lepton, gamma-ray and neutrino yields produced by the inelastic interactions between several species of stable or long-lived cosmic rays projectiles (p, D, T, 3He, 4He, 6Li, 7Li, 9Be, 10Be, 10B, 11B, 12C, 13C, 14C, 14N, 15N, 16O, 17O, 18O, 20Ne, 24Mg and 28Si) and different target gas nuclei (p, 4He, 12C, 14N, 16O, 20Ne, 24Mg, 28Si and 40Ar). The yields are calculated using FLUKA, a simulation package designed to compute the energy distributions of secondary products with large accuracy in a wide energy range. The present results provide, for the first time, a complete and self-consistent set of all the relevant inclusive cross sections regarding the whole spectrum of secondary products in nuclear collisions. We cover, for the projectiles, a ki...

  1. Measuring the ratio of aqueous diffusion coefficients between 6Li +Cl - and 7Li +Cr - by osmometry

    Science.gov (United States)

    Fritz, Steven J.

    1992-10-01

    Osmotic equilibrium is a singular occurrence in the evolution of an osmotic cell because at this event the net solution flux is zero such that -J w · V¯w = J s · V¯s. At this juncture, the diffusion coefficient of the solute through the membrane (ω) equals the solute flux ( Js) divided by the osmotic pressure (ΔΠ). Because the solute permeability coefficient (ω) is related to the Fickian diffusion coefficient ( D) through the gas constant, temperature, and the membrane's thickness and tortuosity, the ratio of ω values for individual isotopic species equals the ratio of D values for the same isotopic components. A 0.9450 molal LiCl solution was placed within sealed dialysis tubing and osmoted against a kilogram of deionized water at 22°C. Osmotic equilibrium occurred at 164 ± 10 min. The ratio of ω6Li +Cl -/ω7Li +Cl - was measured to be 1.011 ± 0.003 - a value close to the square root of the mass ratio between 7LiCl and 6LiCl (= 1.012) as calculated by Graham's Law. The measured diffusion coefficient ratio was used to predict the degree of hyperfiltration-induced fractionation of Li isotopes as a function of membrane ideality. When a membrane's σ exceeds 0.95 (as is likely for low-porosity shales) the 6Li /7Li ratio on the high-pressure side of the membrane can theoretically vary by more than 0.0017.

  2. Probing the role of Skyrme interactions on the fission dynamics of the 6Li + 238U reaction

    Science.gov (United States)

    Sharma, Ishita; Kumar, Raj; Sharma, Manoj K.

    2017-06-01

    The performance of selected five Skyrme forces (out of a set of 240), tested by Dutra et al., is analyzed in view of fusion-fission dynamics. These forces are assumed to perform better for neutron-rich systems, so the choice of the reaction is accordingly made by opting for a neutron-rich target in 6Li + 238U reaction. This reaction is diagnosed further in reference to fusion hindrance within the dynamical approach of the cluster-decay model (DCM). In order to reduce the computational time, three Skyrme forces are figured out with the criteria that these forces cover the barrier characteristics of the remaining two forces as well. The fission cross-sections are successfully addressed at low energies for the 6Li + 238U reaction. However, at relatively higher energies, the excitation functions show theoretical suppression with respect to experimental data, which may be associated with the possible existence of incomplete fusion (ICF). For ICF, we have considered that the 6Li broke into 4He + 2H, as mentioned in the experimental work. The calculations of ICF are carried out for the 4He + 238U reaction with the selected Skyrme forces at E_{c.m.} = 26.20 and 27.51 MeV. These forces address the data nicely for the compound nucleus (CN) as well as ICF processes. Here, the NRAPR force seems to require lesser barrier modification as compared to the other forces, therefore it can be used as an alternate choice for calculating the interaction potential. Additionally, the prediction of cross-sections at lower energies has been done with DCM using the NRAPR force. The ℓ-dependent % barrier modification of the Skyrme forces undertaken is also worked out in reference to fusion hindrance at below barrier energies.

  3. Study of Two-Step Mechanisms in Pion Absorption on $^{6}Li$, $^{12}C$ via Deuteron Emission

    CERN Document Server

    Huber, G M; Papandreou, Z; Hovdebo, J; Naqvi, S I H; Ottewell, D F; Walden, P L; Jones, G; Aslanoglou, X

    2000-01-01

    The (pi+,pd), and (pi+,dd) reactions were investigated with pions of 100 and 165 MeV kinetic energy on 6Li and 12C targets. In comparison with previously published (pi+,pp) data on the same targets and at the same beam energies, kinematic regions were identified in which the neutron pickup process n+p->d dominated the observed deuteron yield. The importance of this mechanism increases with energy, contributing half of the observed cross section at 165 MeV. The contribution of direct quasi-triton absorption is significant only at 100 MeV.

  4. {sup 16}O resonances near 4α threshold through {sup 12}C({sup 6}Li,d) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M. R. D.; Borello-Lewin, T.; Miyake, H.; Horodynski-Matsushigue, L. B.; Duarte, J. L. M.; Rodrigues, C. L.; Faria, P. Neto de [Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05314-970, São Paulo, SP (Brazil); Cunsolo, A.; Cappuzzello, F.; Foti, A.; Agodi, C.; Cavallaro, M. [INFN - Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Napoli, M. di; Ukita, G. M. [Faculdade de Psicologia, Universidade de Santo Amaro, R. Prof. Eneas da Siqueira Neto, 340, CEP 04829-300, São Paulo, SP (Brazil)

    2014-11-11

    Several narrow alpha resonant {sup 16}O states were detected through the {sup 12}C({sup 6}Li,d) reaction, in the range of 13.5 to 17.5 MeV of excitation energy. The reaction was measured at a bombarding energy of 25.5 MeV employing the São Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion technique. Experimental angular distributions associated with natural parity quasi-bound states around the 4α threshold are presented and compared to DWBA predictions. The upper limit for the resonance widths obtained is near the energy resolution (15 keV)

  5. Synthesis of Enriched 10B Boric Acid of Nuclear Grade

    Institute of Scientific and Technical Information of China (English)

    张雷; 张卫江; 徐姣; 任新

    2014-01-01

    An economic and effective method of preparing enriched 10B boric acid was established by chemical reac-tion of enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certain conditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factors were investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yield of enriched 10B boric acid could reach 97. 2%and the purity was up to 94. 1%under the following conditions:the tem-perature was 50—60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystal-lization and titration analysis, the purity of the product could reach over 99. 2%from 94.1%.

  6. Analysis of the normal optical, Michel and molecular potentials on the $^{40}$Ca($^6$Li, d)$^{44}$ Ti reaction

    Indian Academy of Sciences (India)

    MAZUMDER UTTAM K; SOMADDER ANOCK; HOQUE ENAMUL; HAQUE YASMEEN; DAS SUSANTA K; SEN GUPTA H M

    2016-06-01

    Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the $^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of $^{44}$Ti byusing the normal optical, Michel and molecular potentials. The extracted spectroscopic factors for the three optical potentials are compared with those of some previous studies of zero-range (ZR) calculations of the$^{40}$Ca($^{6}$Li, d)$^{44}$Ti reaction using the normal optical potential. The $\\chi^{2}$ values of all the levels are obtained for the three optical potentials to estimate the quality of the fits. Molecular and Michel potentials have been used for the first time to analyse the four-nucleon transfer reaction and it seems that the molecular potential fits the experimental data more satisfactorily for some of the states than the normal optical and Michel potentials.

  7. Low energy R-matrix fits for the 6Li(d,a)4He S factor

    CERN Document Server

    Grineviciute, J; Lamia, L; Spitaleri, C; La Cognata, M

    2014-01-01

    Background: The information about the 6Li(d,a)4He reaction rates of the astrophysical interest can be obtained by extrapolating direct data to the lower energies, or by indirect methods. The indirect Trojan Horse method, as well as various R-matrix and polynomial fits to direct data, estimate the electron screening energies much larger than the adiabatic limit. Calculations that include the subthreshold resonance estimate smaller screening energies. Purpose: Obtain the 6Li(d,a)4He reaction R-matrix parameters and the astrophysical S factor for the energies relevant to the stellar plasmas by fitting the R-matrix formulas for the subthreshold resonances to the S factor data above 60 keV. Methods: The bare S factor is calculated using the single and the two-level R-matrix formulas for the closest to the threshold 0+ and 2+ subthreshold states at 22.2, 20.2 and 20.1 MeV. The electron screening potential Ue is then obtained by fitting it as a single parameter to the low energy data. Results: The low energy S facto...

  8. Theoretical study of the $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma $ astrophysical capture process in a three-body model

    CERN Document Server

    Tursunov, E M; Turakulov, S A; Bray, I

    2016-01-01

    The astrophysical capture process $\\alpha+d$ $\\rightarrow$ $^6$Li + $\\gamma$ is studied in a three-body model. The initial state is factorized into the deuteron bound state and the $\\alpha+d$ scattering state. The final nucleus $^6$Li(1+) is described as a three-body bound state $\\alpha+n+p$ in the hyperspherical Lagrange-mesh method. The contribution of the E1 transition operator from the initial isosinglet states to the isotriplet components of the final state is estimated to be negligible. An estimation of the forbidden E1 transition to the isosinglet components of the final state is comparable with the corresponding results of the two-body model. However, the contribution of the E2 transition operator is found to be much smaller than the corresponding estimations of the two-body model. The three-body model perfectly matches the new experimental data of the LUNA collaboration with the help of the spectroscopic factor 2.586, very consistent with the three-body structure of the final state.

  9. Resonance and non-resonance effect of continuum states of 6Li on elastic scattering angular distributions

    Science.gov (United States)

    Gómez Camacho, A.

    2016-07-01

    CDCC calculations of elastic scattering angular distributions for reactions of the weakly bound projectile 6Li with targets 28Si and 58Ni at energies around the Coulomb barrier are presented. Special emphasis is given to account for the effect of couplings from 6Li resonance states l = 2, J π = 3+, 2+, 1+. Similarly, the effect produced by non-resonant state couplings is studied. The convergent calculations are carried out with global α-target and d-target interactions. The calculated elastic scattering angular distributions are in general in good agreement with the measurements for the systems considered in this work. It is found that the calculations with only resonance states are very similar to that with all couplings (resonance+non-resonance). So, the absence of these states have a strong effect on elastic scattering (non-resonance states calculation). It is shown that the effects increase as the collision energy increases. An interpretation of the strength of the different effects is given in terms of the polarization potentials that emerge from the different couplings.

  10. Interplay of projectile breakup and target excitation in reactions induced by weakly bound nuclei

    Science.gov (United States)

    Gómez-Ramos, M.; Moro, A. M.

    2017-03-01

    Background: Reactions involving weakly bound nuclei require formalisms able to deal with continuum states. The majority of these formalisms struggle to treat collective excitations of the systems involved. For continuum-discretized coupled channels (CDCC), extensions to include target excitation have been developed but have only been applied to a small number of cases. Purpose: In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. Methods: We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Results: Reactions 58Ni(d ,d )*58Ni , 24Mg(d ,d )*24Mg , 144Sm(6Li,6Li)*144Sm , and 9Be(6Li,6Li)*9Be are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. Conclusions: The studied CDCC method has proven to be an accurate tool to describe target excitation in reactions with weakly bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross-section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup.

  11. Prospective conceptual qualification of hybrid centrifugation/distillatory for {sup 6}LI nuclear fusion technology scaled supply demands; Calificacion conceptual prospectiva de centrifugador/destilador hibrido para produccion de {sup 6}Li a demanda de la tecnologia Nuclear Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Sedano, L.; Herranz, J. L.; Casado, J. L.; Castro, P.; Xiberta, J.

    2013-07-01

    The change in the demand for exploitation of lithium as a resource appears during the last decade, related to the development of the ion-Li batteries market and with the requirements of Nuclear Fusion fuels (deuterium and lithium) as coming energy option. A prospective analysis of synergistic demands of both markets, in its technical and in its economic aspects appears of prospective interest. The civil market {sup 6}Li/{sup 7}Li enrichment demand is analyzed. Specific technological developments permitting on-line production according to demand is discussed. A [centrifugation /thermal diffusion / combined distillation] technique is selected and qualified as technologically viable option for scaled production of litiated-forms. A conceptual design of a production plant is finally proposed according to the new technical capability.

  12. 同位素7Li和6Li的性质殊异%The diverse of isotopes 7 Li and 6 Li

    Institute of Scientific and Technical Information of China (English)

    朱正和; 宋江锋; 罗德礼

    2014-01-01

    本文研究了同位素7 Li和6 Li在几个方面的性质差异.用相对论量子力学计算指出,6 Li的电子能级比7 Li的能级低,同时,对电偶极E (1)和磁偶极M (1)的能级跃迁波长,6 Li的跃迁波长都要比7 Li的长.由于7 Li和6 Li的核自旋的大小不同,可以看出在磁场2万高斯和温度100-20 K之间,7 Li的磁极化比6 Li的约大13倍.7 Li和6 Li的磁极化这种差异,也是一种可能的同位素7 Li/6 Li的分离方法.%The diverse of isotopes 7 Li and 6 Li was examined on the several respects.The calculations of relativistic quantum mechanics shows that the energy levels of 6 Li are lower than that of 7 Li, and therefore the transitional wave length of E(1) and M(1) for 6 Li are longer than that of 7 Li.The variation of couple constant due to the different nu-clear spin of 7 Li and 6 Li could be as a basis for the isotope separation between 7 Li and 6 Li.Ratio of the molar intensi-ty of magnetization of 7 Li to 6 Li is about 13 under 100-20 K and 20, 000 gauss, which is favorable to separate out 6 Li.

  13. Effect of compound nuclear reaction mechanism in 12C(6Li,d) reaction at sub-Coulomb energy

    Science.gov (United States)

    Mondal, Ashok; Adhikari, S.; Basu, C.

    2017-09-01

    The angular distribution of the 12C(6Li,d) reaction populating the 6.92 and 7.12 MeV states of 16O at sub-Coulomb energy (Ecm=3 MeV) are analysed in the framework of the Distorted Wave Born Approximation (DWBA). Recent results on excitation function measurements and backward angle angular distributions derive ANC for both the states on the basis of an alpha transfer mechanism. In the present work, we show that considering both forward and backward angle data in the analysis, the 7.12 MeV state at sub-Coulomb energy is populated from Compound nuclear process rather than transfer process. The 6.92 MeV state is however produced from direct reaction mechanism.

  14. Characterization of charge-exchange collisions between ultracold $\\rm{^6Li}$ atoms and $\\rm{^{40}Ca^+}$ ions

    CERN Document Server

    Saito, R; Sasakawa, M; Nakai, R; Raoult, M; Silva, H Da; Dulieu, O; Mukaiyama, T

    2016-01-01

    We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of $^6$Li atoms and $^{40}$Ca$^+$ ions in the collision energy range from 0.2 mK to 1 K. Deliberately excited ion micromotion is used to control the collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the $^{40}$Ca$^+$ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow temperature regime.

  15. Hypernuclear spectroscopy of products from 6Li projectiles on a carbon target at 2 AGeV

    CERN Document Server

    Rappold, C; Nakajima, D; Saito, T R; Bertini, O; Bianchin, S; Bozkurt, V; Kavatsyuk, M; Ma, Y; Maas, F; Minami, S; Özel-Tashenov, B; Yoshida, K; Achenbach, P; Ajimura, S; Aumann, T; Gayoso, C Ayerbe; Bhang, H C; Caesar, C; Erturk, S; Fukuda, T; Göküzüm, B; Guliev, E; Hiraiwa, T; Hoffmann, J; Ickert, G; Ketenci, Z S; Khaneft, D; Kim, M; Kim, S; Koch, K; Kurz, N; Fèvre, A Le; Mizoi, Y; Moritsu, M; Nagae, T; Nungesser, L; Okamura, A; Ott, W; Pochodzalla, J; Sakaguchi, A; Sako, M; Schmidt, C J; Sekimoto, M; Simon, H; Sugimura, H; Takahashi, T; Tambave, G J; Tamura, H; Trautmann, W; Voltz, S; Yokota, N; Yoon, C J

    2013-01-01

    A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy-ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of 6Li projectiles on a carbon target at 2 AGeV was performed. Signals of the \\Lambda-hyperon and 3\\Lambda H and 4\\Lambda H hypernuclei were observed for final states of p+\\pi^-, 3He+\\pi^- and 4He+\\pi^-, respectively, with significance values of 6.7, 4.7 and 4.9\\sigma. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be $262 ^{+56}_{-43} \\pm 45$ ps for \\Lambda, $183 ^{+42}_{-32} \\pm 37$ ps for 3\\Lambda H, and $140 ^{+48}_{-33}\\pm 35 $ ps for 4\\Lambda H.

  16. Magnetic control of ultra-cold $^6$Li and $^{174}$Yb($^3P_2$) atom mixtures with Feshbach resonances

    CERN Document Server

    Petrov, Alexander; Kotochigova, Svetlana

    2015-01-01

    We theoretically evaluate the feasibility to form magnetically-tunable Feshbach molecules in collisions between fermionic $^6$Li atoms and bosonic metastable $^{174}$Yb($^3$P$_2$) atoms. In contrast to the well-studied alkali-metal atom collisions, collisions with meta-stable atoms are highly anisotropic. Our first-principle coupled-channel calculation of these collisions reveals the existence of broad Feshbach resonances due to the combined effect of anisotropic-molecular and atomic-hyperfine interactions. In order to fit our predictions to the specific positions of experimentally-observed broad resonance structures \\cite{Deep2015} we optimized the shape of the short-range potentials by direct least-square fitting. This allowed us to identify the dominant resonance by its leading angular momentum quantum numbers and describe the role of collisional anisotropy in the creation and broadening of this and other resonances.

  17. AN UPDATED {sup 6}Li(p, {alpha}){sup 3}He REACTION RATE AT ASTROPHYSICAL ENERGIES WITH THE TROJAN HORSE METHOD

    Energy Technology Data Exchange (ETDEWEB)

    Lamia, L.; Spitaleri, C.; Sergi, M. L. [Dipartimento di Fisica e Astronomia, Universita di Catania, I-95123 Catania (Italy); Pizzone, R. G.; Tumino, A.; La Cognata, M. [INFN-Laboratori Nazionali del Sud, I-95125 Catania (Italy); Tognelli, E.; Degl' Innocenti, S.; Prada Moroni, P. G. [Dipartimento di Fisica, Universita di Pisa, I-56127 Pisa (Italy); Pappalardo, L. [Dipartimento di Fisica e Scienze della Terra, Universita di Ferrara, I-44100 Ferrara (Italy)

    2013-05-01

    The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. {sup 6}Li is the most fragile of lithium's stable isotopes and is largely destroyed in most stars during the pre-main-sequence (PMS) phase. For these stars, the convective envelope easily reaches, at least at its bottom, the relatively low {sup 6}Li ignition temperature. Thus, gaining an understanding of {sup 6}Li depletion also gives hints about the extent of convective regions. For this reason, charged-particle-induced reactions in lithium have been the subject of several studies. Low-energy extrapolations of these studies provide information about both the zero-energy astrophysical S(E) factor and the electron screening potential, U{sub e} . Thanks to recent direct measurements, new estimates of the {sup 6}Li(p, {alpha}){sup 3}He bare-nucleus S(E) factor and the corresponding U{sub e} value have been obtained by applying the Trojan Horse method to the {sup 2}H({sup 6}Li, {alpha} {sup 3}He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T{sub 9} and its impact on the surface lithium depletion in PMS models with different masses and metallicities has been evaluated in detail by adopting an updated version of the FRANEC evolutionary code.

  18. Development of antireflection coatings with a sup 6 LiF/ sup 6 sup 2 Ni multilayer converter for ultracold neutron detectors

    CERN Document Server

    Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Schott, W

    2002-01-01

    High efficiency detectors for ultracold neutrons (UCN) are needed at the new high flux neutron source, Forschungsreaktor Muenchen II. In the development described, silicon PIN diodes were chosen to detect the alpha-particles or the tritons created in the reaction sup 6 Li(n,alpha)t. The high reflectance of UCN on sup 6 Li with its positive optical potential must be compensated by a material with negative optical potential. The isotope sup 6 sup 2 Ni was chosen for this. To avoid problems due to chemical reactions of Li with humidity, the compound sup 6 LiF was chosen. One hundred and fifty double layers of sup 6 LiF/ sup 6 sup 2 Ni had to be deposited by physical vapor deposition on silicon PIN diodes which had already been coated with 88 nm approx 77 mu g/cm sup 2 of sup 5 sup 8 Ni for reflection of the UCN. The theoretical optimal thickness of the sup 6 sup 2 Ni layers is 3 nm, and that of sup 6 LiF is 6 nm. Since expensive isotopes were involved, a small source-to-substrate distance had to be used, but wit...

  19. Interaction of eta mesons with nuclei

    CERN Document Server

    Kelkar, N G; Upadhyay, N J; Jain, B K

    2013-01-01

    Back in the mid eighties, a new branch of investigation which was related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta meson producing reactions. The vast literature of experimental as well as theoretical works which studied various aspects of eta producing reactions such as the $\\pi ^+$ $n$ $\\to \\eta p$, $p d \\to ^3$He $\\eta$, $p \\,^6$Li $\\to ^7$Be $\\eta$ and $\\gamma ^3$He $\\to \\eta$ X, to name a few, had but one objective in mind: to understand the eta - nucleon ($\\eta N$) and hence the $\\eta$-nucleus interaction which could explain the production data and confirm the existence of some $\\eta$-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the $\\eta N$ and hence the $\\eta$-nu...

  20. Breakup Coupling Effects on Near-Barrier {sup 6}Li, {sup 7}Be and {sup 8}B + {sup 58}Ni Elastic Scattering Compared

    Energy Technology Data Exchange (ETDEWEB)

    Keeley, N. [Department of Nuclear Reactions, Andrzej Soltan Institute for Nuclear Studies, ul. Hoza 69, 00-681 Warsaw (Poland); Mackintosh, R.S. [Department of Physics and Astronomy, Open University, Milton Keynes, MK7 6AA (United Kingdom); Beck, C. [Institut Pluridisciplinaire Hubert Curien et Universite Louis Pasteur, Boite Postale 28, F-67037 Strasbourg Cedex 2 (France)

    2010-03-01

    New data for near-barrier {sup 6}Li, {sup 7}Be and {sup 8}B + {sup 58}Ni elastic scattering enable a comparison of breakup coupling effects for these loosely-bound projectiles. Coupled Discretised Continuum Channels (CDCC) calculations suggest that the large total reaction cross sections for {sup 8}B + {sup 58}Ni are dominated by breakup at near-barrier energies, unlike {sup 6}Li and {sup 7}Be where breakup makes a small contribution. In spite of this, the CDCC calculations show a small coupling influence due to breakup for {sup 8}B, in contrast to the situation for {sup 6}Li and {sup 7}Be. An examination of the S matrices gives a clue to this counter-intuitive behaviour.

  1. A method for investigation of the D(4He, γ)6Li reaction in the Ultralow energy region under a high background

    Science.gov (United States)

    Bystritsky, V. M.; Dudkin, G. N.; Krylov, A. R.; Gazi, S.; Huran, J.; Nechaev, B. A.; Padalko, V. N.; Sadovsky, A. B.; Tuleushev, Yu. Zh.; Filipowicz, M.; Philippov, A. V.

    2016-07-01

    The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of 7Li is 2-4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of 6Li, recent more accurate optical investigations have yielded only the upper limit on the 6Li/7Li ratio, which makes the problem of 6Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D(4He, γ)6Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D(4He, γ)6Li reaction proceeding in zirconium deuteride at the incident 4He+ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D(4He, 4He)D→D(D, n)3He→(n, γ) and/or (n, n‧γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D(4He, γ)6Li reaction cross section σ≤7·10-36 cm2 at the 90% confidence level is obtained.

  2. A method for investigation of the D({sup 4}He, γ){sup 6}Li reaction in the Ultralow energy region under a high background

    Energy Technology Data Exchange (ETDEWEB)

    Bystritsky, V.M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Dudkin, G.N. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Krylov, A.R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Gazi, S.; Huran, J. [Institute of Electrical Engineering, Slovak Academy of Sciences, Bratislava (Slovakia); Nechaev, B.A.; Padalko, V.N. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); Sadovsky, A.B. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Tuleushev, Yu.Zh. [Institute of Nuclear Physics, Ministry of Power Engineering, Almaty (Kazakhstan); Filipowicz, M. [Faculty of Energy and Fuels, University of Science and Technologies, Krakow (Poland); Philippov, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-07-21

    The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of {sup 7}Li is 2–4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of {sup 6}Li, recent more accurate optical investigations have yielded only the upper limit on the {sup 6}Li/{sup 7}Li ratio, which makes the problem of {sup 6}Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D({sup 4}He, γ){sup 6}Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D({sup 4}He, γ){sup 6}Li reaction proceeding in zirconium deuteride at the incident {sup 4}He{sup +}ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D({sup 4}He, {sup 4}He)D→D(D, n){sup 3}He→(n, γ) and/or (n, n′γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D({sup 4}He, γ){sup 6}Li reaction cross section σ≤7·10{sup −36} cm{sup 2} at the 90% confidence level is obtained.

  3. (/sup 6/Li,d) reactions on /sup 24/Mg and /sup 26/Mg at 73 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T.; Haga, K.; Yasue, M.; Sato, K. (Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study); Ogino, K.; Kadota, Y.; Tochi, M.; Makino, K. (Kyoto Univ. (Japan). Faculty of Engineering); Kitahara, T. (Yamanashi Medical Coll. (Japan)); Shiba, T. (Kyoto Univ. (Japan). Lab. of Nuclear Reaction)

    1983-05-09

    The sup(24,26)Mg(/sup 6/Li, d)sup(28,30)Si reactions have been studied at 73 MeV bombarding energy. The angular distributions were analyzed with exact finite-range distorted wave Born approximation calculations assuming a direct ..cap alpha..-cluster transfer. Extracted spectroscopic strengths leading to low-lying levels of /sup 28/Si and relative spectroscopic strengths between transitions to /sup 28/Si and /sup 30/Si ground states are consistent with those previously obtained by several ..cap alpha..-transfer reactions. Many strongly populated levels have been observed at Esub(x)> or approx.10 MeV for /sup 28/Si. A marked similarity was found between the deuteron spectrum and the /sup 24/Mg(..cap alpha.., ..cap alpha..)/sup 24/Mg excitation function in this excitation energy region. A brief comparison of the present ..cap alpha..-transfer results with previous two-nucleon transfer data leading to sup(28,30)Si is also presented.

  4. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    Science.gov (United States)

    Wang, C. L.; Riedel, R. A.

    2016-01-01

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a1, b0) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  5. Development of neutron-monitor detector using liquid organic scintillator coupled with 6Li + ZnS(Ag) Sheet.

    Science.gov (United States)

    Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Takahashi, Fumiaki

    2004-01-01

    A phoswitch-type detector has been developed for monitoring neutron doses in high-energy accelerator facilities. The detector is composed of a liquid organic scintillator (BC501A) coupled with ZnS(Ag) sheets doped with 6Li. The dose from neutrons with energies above 1 MeV is evaluated from the light output spectrum of the BC501A by applying the G-function, which relates the spectrum to the neutron dose directly. The dose from lower energy neutrons, on the other hand, is estimated from the number of scintillations emitted from the ZnS(Ag) sheets. Characteristics of the phoswitch-type detector were studied experimentally in some neutron fields. It was found from the experiments that the detector has an excellent property of pulse-shape discrimination between the scintillations of BC501A and the ZnS(Ag) sheets. The experimental results also indicate that the detector is capable of reproducing doses from thermal neutrons as well as neutrons with energies from one to several tens of megaelectronvolts (MeV).

  6. Hypernuclear production cross section in the reaction of 6Li + 12C at 2A GeV

    Directory of Open Access Journals (Sweden)

    C. Rappold

    2015-07-01

    Full Text Available Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI Collaboration exploiting the reaction of 6Li + 12C at 2A GeV or sNN=2.70 GeV. A production cross section of 3.9±1.4 μb for 3ΛH and of 3.1±1.0 μb for 4ΛH respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7±0.8 mb. A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3ΛH/4ΛH, 3ΛH/Λ and 4ΛH/Λ were included in the inference procedure. The strangeness population factors S3 and S4 of 3ΛH and 4ΛH respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3ΛH, and 4ΛH together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported.

  7. Hypernuclear spectroscopy of products from {sup 6}Li projectiles on a carbon target at 2A GeV

    Energy Technology Data Exchange (ETDEWEB)

    Rappold, C., E-mail: c.rappold@gsi.de [Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany); GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Kim, E. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Seoul National University, Gwanakro Sillim-dong, Gwanak-gu, Seoul 151-747 (Korea, Republic of); Nakajima, D. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Saito, T.R., E-mail: t.saito@gsi.de [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); The Helmholtz Institute Mainz (HIM), J.J. Becherweg 40, 55099 Mainz (Germany); Bertini, O. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); Bianchin, S. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Bozkurt, V. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Nigde University, 51100 Nigde (Turkey); Kavatsyuk, M. [KVI, University of Groningen, Zernikelaan 25, NL-9747 AA Groningen (Netherlands); Ma, Y. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); Maas, F. [GSI Helmholtz Centre for Heavy Ion Research, Planckstrasse 1, 64291 Darmstadt (Germany); Johannes Gutenberg-Universität Mainz, J.J. Becherweg 40, 55099 Mainz (Germany); The Helmholtz Institute Mainz (HIM), J.J. Becherweg 40, 55099 Mainz (Germany); and others

    2013-09-02

    A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of {sup 6}Li projectiles on a carbon target at 2A GeV was performed. Signals of the Λ-hyperon and {sup 3}{sub Λ}H and {sup 4}{sub Λ}H hypernuclei were observed for final states of p+π{sup −}, {sup 3}He+π{sup −} and {sup 4}He+π{sup −}, respectively, with significance values of 6.7, 4.7 and 4.9σ. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262{sub −43}{sup +56}±45 ps for Λ, 183{sub −32}{sup +42}±37 ps for {sup 3}{sub Λ}H, and 140{sub −33}{sup +48}±35 ps for {sup 4}{sub Λ}H.

  8. Improved neutron-gamma discrimination for a {sup 6}Li-glass neutron detector using digital signal analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C. L., E-mail: wangc@ornl.gov; Riedel, R. A. [Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2016-01-15

    A {sup 6}Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at Spallation Neutron Source. Traditional Pulse-Height Analysis (PHA) for Neutron-Gamma Discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 10{sup 4}. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, six digital signal analysis methods of individual waveforms acquired from photomultiplier tubes were proposed using (i) charge integration, (ii) pulse-amplitude histograms, (iii) power spectrum analysis combined with the maximum pulse-amplitude, (iv) two event parameters (a{sub 1}, b{sub 0}) obtained from a Wiener filter, (v) an effective amplitude (m) obtained from an adaptive least-mean-square filter, and (vi) a cross-correlation coefficient between individual and reference waveforms. The NGD ratios are about 70 times those from the traditional PHA method. Our results indicate the NGD capabilities of neutron Anger cameras based on GS20 scintillators can be significantly improved with digital signal analysis methods.

  9. Multi-elemental characterization of organic liquid samples by use of a 13 MeV {sup 6}Li{sup 3+} beam

    Energy Technology Data Exchange (ETDEWEB)

    Liendo, J.A., E-mail: jliendo@usb.v [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Bernal, M.A., E-mail: mbernal@usb.v [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Gonzalez, A.C. [Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela, Bolivarian Republic of); Caussyn, D.D.; Fletcher, N.R.; Momotyuk, O.A. [Department of Physics, Florida State University, Tallahassee (United States); Muruganathan, R.M. [Department of Chemistry, Florida State University, Tallahassee (United States); Roeder, B.T.; Wiedenhoever, I. [Department of Physics, Florida State University, Tallahassee (United States); Fischer, T. [Department of Chemistry, Florida State University, Tallahassee (United States); Kemper, K.W.; Barber, P. [Department of Physics, Florida State University, Tallahassee (United States); Sajo-Bohus, L. [Department of Physics, Simon Bolivar University, PO Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of)

    2009-10-15

    Evaporated amniotic fluid (AF) targets have been bombarded with a 13 MeV {sup 6}Li{sup 3+} beam. Forward angle data have served to identify the {sup 1}H({sup 6}Li,{sup 1}H){sup 6}Li reaction as an alternative for hydrogen characterization of such organic samples. Detected {sup 6}Li ions elastically scattered from C, N, O, Na and Cl can also be used to determine the concentrations of these elements in AF. The analyzed AF samples have been diluted with distilled water. The effect of sample dilution on the improvement of spectrum energy resolution has been observed, confirming previous reports. The hydrogen concentration determined in the studied AF targets is shown to vary linearly with sample dilution. Two detector arrangements have been used to find out which detection scheme is the most convenient. The combination of a counter telescope and a single detector, set up at the same polar angle on the opposite side of the beam, seems to be the best choice to have a reliable particle identification and an adequate energy resolution simultaneously.

  10. Spectroscopic strengths for /sup 6/Li-induced alpha-particle transfers on /sup 18/O at 72 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T.; Ogino, K.; Kadota, Y.; Haga, K.; Kitahara, T.; Shiba, T.

    1982-08-01

    The /sup 18/O(/sup 6/Li,d)/sup 22/Ne reaction has been studied at 72-MeV bombarding energy. The angular distributions for transitions to low-lying states in /sup 22/Ne are fitted by exact finite-range distorted-wave Born approximation calculations and yield relative spectroscopic factors in good agreement with theoretical predictions.

  11. A new study of $^{10}$B(p,$\\alpha$)$^{7}$Be reaction at low energies

    CERN Document Server

    Caciolli, A; Broggini, C; La Cognata, M; Lamia, L; Menegazzo, R; Mou, L; Puglia, S M R; Rigato, V; Romano, S; Alvarez, C Rossi; Sergi, M L; Spitaleri, C; Tumino, A

    2016-01-01

    The $^{10}$B(p,$\\alpha$)$^{7}$Be reaction is of great interest since it has many applications in different fields of research such as nuclear astrophysics, nuclear physics, and models of new reactors for clean energy generation. This reaction has been studied at the AN2000 accelerator of the INFN National Laboratories of Legnaro (LNL). The total cross section has been measured in a wide energy range (250 $-$ 1182 keV) by using the activation method. The decays of the $^7$Be nuclei produced by the reaction were measured at the low counting facility of LNL by using two fully shielded high-purity germanium detectors. The present dataset shows a large discrepancy with respect to one of the previous data at the same energies and reduces the total uncertainty to the level of 6\\%. An R-matrix calculation has been performed on the present data using the parameters from previous Trojan Horse measurements for the 10 and 500 keV resonances. The present data do not lay on the R-matrix fit in one point suggesting the exis...

  12. Interplay of projectile breakup and target excitation in reactions induced by weakly-bound nuclei

    CERN Document Server

    Gomez-Ramos, M

    2016-01-01

    In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Reactions 58Ni(d, d) 58Ni*, 24Mg(d, d) 24Mg* , 144Sm( 6Li, 6Li) 144Sm* and 9Be( 6Li, 6Li) 9Be* are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. The studied CDCC method is proved to be an accurate tool to describe target excitation in reactions with weakly-bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup.

  13. Novel 4{pi} Detection System for the Measurement of the {sup 6}Li(n,{alpha}){sup 3}H Reaction Cross Section

    Energy Technology Data Exchange (ETDEWEB)

    Giorginis, Georgios; Bencardino, Raffaele [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel (Belgium)

    2011-12-13

    A dedicated one-dimensional Time Projection Chamber (1D-TPC) was designed and produced at IRMM to determine the {sup 6}Li(n,{alpha}){sup 3}H cross section in the 0.4-2.8 MeV energy range, aiming at 5% accuracy. The basic TPC components were a twin gridded ionisation chamber (GIC) with interwired electrodes and fast digitisation of the anode and cathode signals. The energy of both reaction products emitted from a thin {sup 6}LiF sample at the common TPC cathode was measured. A Kr(97%)CO{sub 2}(3%) mixture was used as the detector gas at a pressure up to 3.5 bar. A {sup 238}U sample mounted on the cathode of an ionisation chamber without grid was used as the neutron flux monitor. Special care was taken to reduce the experimental sources of uncertainty. The beam-monitor {sup 238}U sample was characterised at IRMM by low-geometry {alpha}-counting with an accuracy of 0.1%. A {sup 6}Li sample was produced at IRMM by vacuum evaporation of {sup 6}LiF onto transparent aluminium backing. The number of {sup 6}Li atoms will be measured via Thermal Neutron Depth Profiling with an expected accuracy of 2% with respect to an IRMM Standard Reference Material. First test measurements were performed using a monoenergetic neutron beam produced by the T(p,n){sup 3}He reaction at the IRMM 7 MV Van de Graaff accelerator. The experimental method and preliminary results are presented.

  14. Functions of MgH2 in hydrogen storage reactions of the 6LiBH4-CaH2 reactive hydride composite.

    Science.gov (United States)

    Zhou, Yifan; Liu, Yongfeng; Zhang, Yu; Gao, Mingxia; Pan, Hongge

    2012-08-28

    A significant improvement of hydrogen storage properties was achieved by introducing MgH(2) into the 6LiBH(4)-CaH(2) system. It was found that ~8.0 wt% of hydrogen could be reversibly stored in a 6LiBH(4)-CaH(2)-3MgH(2) composite below 400 °C and 100 bar of hydrogen pressure with a stepwise reaction, which is superior to the pristine 6LiBH(4)-CaH(2) and LiBH(4) samples. Upon dehydriding, MgH(2) first decomposed to convert to Mg and liberate hydrogen with an on-set temperature of ~290 °C. Subsequently, LiBH(4) reacted with CaH(2) to form CaB(6) and LiH in addition to further hydrogen release. Hydrogen desorption from the 6LiBH(4)-CaH(2)-3MgH(2) composite finished at ~430 °C in non-isothermal model, a 160 °C reduction relative to the 6LiBH(4)-CaH(2) sample. JMA analyses revealed that hydrogen desorption was a diffusion-controlled reaction rather than an interface reaction-controlled process. The newly produced Mg of the first-step dehydrogenation possibly acts as the heterogeneous nucleation center of the resultant products of the second-step dehydrogenation, which diminishes the energy barrier and facilitates nucleation and growth, consequently reducing the operating temperature and improving the kinetics of hydrogen storage.

  15. Characterization of {sup 6}LiF:Mg,Cu,P (TLD-600 H) estimate of E, b and s parameters

    Energy Technology Data Exchange (ETDEWEB)

    Andres, P. A., E-mail: andresp@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    LiF:Mg,Cu,P dosemeters are useful for low-dose measurements because of its high sensitivity compared to the LiF:Mg,Ti dosemeters. {sup 7}LiF:Mg,Cu,P have been used for environmental dosimetry in Bariloche Atomic Centre for almost a decade. Since {sup 6}LiF:Mg,Cu,P dosemeters were intended to be used for X ray diagnosis dosimetry in neonatology, they had to be characterized first. The main goal of measuring and analyzing Tl glow curves is the extraction of some parameters that can be used to describe the Tl process in the material. This job focused on the estimation of the activation energy E for the Tl traps, the frequency factor s and the order of kinetics b of the Tl process. Furthermore, the most appropriate time-temperature profile (Ttp) was determined as well as the annealing temperature and time, which resulted being 240 degrees C for 10 minutes. The Ttp used was 140 degrees C for 10 seconds, a heating rate of 20/s until 240 degrees C, remaining at this temperature for 20 seconds, and then an exponential cooling until 50 degrees C. After applying the whole glow-peak method for different orders of kinetic, and the Kitis equation assuming a first order kinetics, the values obtained were: E = (1.066 ± 0.025) eV, as a weighted average of both methods, and a frequency factor s = (3.57 ± 1.56) E-10 s{sup -1} again as a weighted average of both methods. In both cases a first order kinetics (b = 1) was assumed. The dosemeters were irradiated with a calibrated {sup 137}Cs source and read with a Harshaw TLD{sup TM} Model 3500 reader resulting in a minimum detectable dose of about 20 μGy. (Author)

  16. miR-10b promotes invasion by targeting KLF4 in osteosarcoma cells.

    Science.gov (United States)

    Wang, Jing; Wang, Bing; Chen, Ling-Qiang; Yang, Jin; Gong, Zhi-Qiang; Zhao, Xue-Ling; Zhang, Chun-Qiang; Du, Kai-Li

    2016-12-01

    Osteosarcoma is a common malignancy with high rate of metastasis. miR-10b has been reported to be expressed in many types of tumors abnormally and be associated with cancer carcinogenesis and progression. But the function of miR-10b in osteosarcoma is still unknown. So this study was aimed to investigate the role of miR-10b in osteosarcoma development. miR-10b expression in osteosarcoma tissues and osteosarcoma cells were detected using real time PCR. The effects of miR-10b on osteosarcoma cells proliferation, apoptosis, migration and invasion were detected using CCK-8 assay, flow cytometry, wound-healing assay and transwell assay, respectively. The relationship between miR-10b and KLF4 was evaluated using dual-luciferase assay, correlation analysis. miR-10b was highly expressed in osteosarcoma tissues and osteosarcoma cells. Furthermore, inhibition of miR-10b in osteosarcoma cells depressed the cells proliferation, migration and invasion but promoted cells apoptosis. In addition, KLF4 was down-regulated by miR-10b and miR-10b expression was negatively related to KLF4 expression in osteosarcoma tissue, miR-10b participated in the process of osteosarcoma cells invasion by regulating KLF4 expression. miR-10b is overexpressed in osteosarcoma and KLF4 is the direct target gene of miR-10b. Furthermore, miR-10b promotes osteosarcoma cells progression by downregulating KLF4 expression. These results suggest that miR-10b functions as an oncomiR and play an important role in osteosarcoma cellular processes at least partially through regulating KLF4; miR-10b may be a therapeutic target for osteosarcoma treatment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Upgrade of the POLDI diffractometer with a ZnS(Ag)/6LiF scintillation detector read out with WLS fibers coupled to SiPMs

    OpenAIRE

    Mosset, J. -B.; Stoykov, A.; Davydov, V.; Hildebrandt, M.; Van Swygenhoven, H.; W. Wagner

    2013-01-01

    A thermal neutron detector based on ZnS(Ag)/6LiF scintillator, wavelength-shifting fibers (WLS) and silicon photomultipliers (SiPM) is under development at the Paul Scherrer Institute (PSI) for upgrading the POLDI instrument, a pulse-overlap diffractometer. The design of the detector is outlined, and the measurements performed on a single channel prototype are presented. An innovative signal processing system based on a photon counting approach is under development. Its principle of operation...

  18. Characteristics of a thermal neutrons scintillation detector with the [ZnS(Ag)+$^6$LiF] at different conditions of measurements

    OpenAIRE

    Alekseenko, V. V.; Barabanov, I. R.; Etezov, R. A.; Gavrilyuk, Yu. M.; Gangapshev, A. M.; Gezhaev, A. M.; Kazalov, V. V.; Khokonov, A. Kh.; V.V. Kuzminov; Panasenko, S. I.; Ratkevich, S. S.

    2015-01-01

    A construction of a thermal neutron testing detector with a thin [ZnS(Ag)+$^6$LiF] scintillator is described. Results of an investigation of sources of the detector pulse origin and the pulse features in a ground and underground conditions are presented. Measurements of the scintillator own background, registration efficiency and a neutron flux at different objects of the BNO INR RAS were performed. The results are compared with the ones measured by the $^3$He proportional counter.

  19. Immunohistochemical study of hair follicle stem cells in regenerated hair follicles induced by Wnt10b

    Science.gov (United States)

    Zhang, Yiming; Xing, Yizhan; Guo, Haiying; Ma, Xiaogen; Li, Yuhong

    2016-01-01

    The regulation of the periodic regeneration of hair follicles is complicated. Although Wnt10b has been reported to induce hair follicle regeneration, the characteristics of induced hair follicles, especially the target cells of Wnt10b, have not yet been clearly elucidated. Thus, we systematically evaluated the expression and proliferation patterns of Wnt10b-induced hair follicles. We found that Wnt10b promoted the proliferation of hair follicle stem cells from 24 hours after AdWnt10b injection. Seventy-two hours after AdWnt10b injection, cells outside of bulge area began to proliferate. When the induced hair follicle entered full anagen, although the hair follicle stem cells were normal, canonical Wnt signaling was maintained in the hair precortex cells. Our results reveal that the target cells that overexpressed Wnt10b included hair follicle stem cells, hair precortex cells, and matrix cells.

  20. Ultracold neutron detection with {sup 6}Li-doped glass scintillators. NANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    Energy Technology Data Exchange (ETDEWEB)

    Ban, G.; Lefort, T.; Lemiere, Y.; Naviliat-Cuncic, O.; Pierre, E.; Quemener, G.; Rogel, G. [Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, Caen (France); Bison, G.; Chowdhuri, Z.; Henneck, R.; Lauss, B.; Mtchedlishvili, A.; Schmidt-Wellenburg, P.; Zsigmond, G. [Paul Scherrer Institute, Villigen-PSI (Switzerland); Bodek, K.; Zejma, J. [Jagiellonian University, Marian Smoluchowski Institute of Physics, Cracow (Poland); Geltenbort, P. [Institut Laue-Langevin, Grenoble (France); Griffith, W.C.; Musgrave, M. [University of Sussex, Falmer, Department of Physics and Astronomy, Brighton (United Kingdom); Helaine, V. [Normandie Univ, ENSICAEN, UNICAEN, CNRS/IN2P3, LPC Caen, Caen (France); Paul Scherrer Institute, Villigen-PSI (Switzerland); Kasprzak, M.; Koss, P.A.; Severijns, N.; Wursten, E. [Katholieke Universiteit Leuven, Instituut voor Kernen Stralingsfysica, Leuven (Belgium); Kermaidic, Y.; Pignol, G.; Rebreyend, D. [LPSC, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France); Kirch, K.; Komposch, S.; Krempel, J.; Ries, D. [Paul Scherrer Institute, Villigen-PSI (Switzerland); Institute for Particle Physics, ETH Zuerich, Zuerich (Switzerland); Kozela, A. [Henryk Niedwodniczanski Institute for Nuclear Physics, Cracow (Poland); Piegsa, F.M.; Rawlik, M. [Institute for Particle Physics, ETH Zuerich, Zuerich (Switzerland); Roccia, S. [CSNSM, Universite Paris Sud, CNRS/IN2P3, Orsay (France)

    2016-10-15

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with {sup 6}Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200μm, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a {sup 6}Li-depleted glass bonded to a {sup 6}Li-enriched glass. The technique of optical contact bonding is used between the two glasses in order to eliminate the need for optical glue or grease between them. Relative to a {sup 3}He Strelkov gas detector, the scintillator's detection efficiency is lower for UCN energies close to the scintillator's Fermi potential (85-100 neV), but becomes larger at higher UCN energies. Coupled to a digital data acquisition system, counting rates up to a few 10{sup 5} counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for routine runs of the neutron electric dipole moment experiment is presented. (orig.)

  1. Ultracold neutron detection with 6Li-doped glass scintillators, NANOSC: a fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    CERN Document Server

    Ban, G; Bodek, K; Chowdhuri, Z; Geltenbort, P; Griffith, W C; Hélaine, V; Henneck, R; Kasprzak, M; Kermaidic, Y; Kirch, K; Komposch, S; Koss, P A; Kozela, A; Krempel, J; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Musgrave, M; Naviliat-Cuncic, O; Piegsa, F M; Pierre, E; Pignol, G; Quéméner, G; Rawlik, M; Ries, D; Rebreyend, D; Roccia, S; Rogel, G; Schmidt-Wellenburg, P; Severijns, N; Wursten, E; Zejma, J; Zsigmond, G

    2016-01-01

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200 micrometer, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a 6Li-depleted glass bonded to a 6Li-enriched glass. The optical contact bonding is used between the scintillators in order to obtain a perfect optical contact. The scintillator's detection efficiency is similar to that of a 3He Strelkov gas detector. Coupled to a digital data acquisition system, counting rates up to a few 10^5 counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for the regular runs of the neutron electric dipole moment experiment is presented.

  2. Ultracold neutron detection with 6Li-doped glass scintillators. NANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute

    Science.gov (United States)

    Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Geltenbort, P.; Griffith, W. C.; Hélaine, V.; Henneck, R.; Kasprzak, M.; Kermaidic, Y.; Kirch, K.; Komposch, S.; Koss, P. A.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Musgrave, M.; Naviliat-Cuncic, O.; Piegsa, F. M.; Pierre, E.; Pignol, G.; Quéméner, G.; Rawlik, M.; Ries, D.; Rebreyend, D.; Roccia, S.; Rogel, G.; Schmidt-Wellenburg, P.; Severijns, N.; Wursten, E.; Zejma, J.; Zsigmond, G.

    2016-10-01

    This paper summarizes the results from measurements aiming to characterize ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or GS20 scintillators, with a thickness of 100-200μm, fulfill the ultracold neutron detection requirements with an acceptable neutron-gamma discrimination. This discrimination is clearly improved with a stack of two scintillators: a 6Li-depleted glass bonded to a 6Li-enriched glass. The technique of optical contact bonding is used between the two glasses in order to eliminate the need for optical glue or grease between them. Relative to a 3He Strelkov gas detector, the scintillator's detection efficiency is lower for UCN energies close to the scintillator's Fermi potential (85-100 neV), but becomes larger at higher UCN energies. Coupled to a digital data acquisition system, counting rates up to a few 105 counts/s can be handled. A detector based on such a scintillator stack arrangement was built and has been used in the neutron electric dipole moment experiment at the Paul Scherrer Institute since 2010. Its response for routine runs of the neutron electric dipole moment experiment is presented.

  3. Study of the {sup 10}B(p,αγ){sup 7}Be and {sup 10}B(p,p{sup ′}γ){sup 10}B reactions for PIGE purposes

    Energy Technology Data Exchange (ETDEWEB)

    Lagoyannis, A., E-mail: lagoya@inp.demokritos.gr [Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153.10 Aghia Paraskevi, Athens (Greece); Preketes-Sigalas, K.; Axiotis, M.; Foteinou, V.; Harissopulos, S. [Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153.10 Aghia Paraskevi, Athens (Greece); Kokkoris, M. [National Technical University of Athens, Zografou Campus, 157.80 Athens (Greece); Misaelides, P. [Department of Chemistry, Aristotle University of Thessaloniki, 541.24 Thessaloniki (Greece); Paneta, V. [Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153.10 Aghia Paraskevi, Athens (Greece); National Technical University of Athens, Zografou Campus, 157.80 Athens (Greece); Patronis, N. [Department of Physics, University of Ioannina, 45110 Ioannina (Greece)

    2015-01-01

    Differential cross sections were measured at 8 angles and at proton energies from 2 to 5 MeV for the {sup 10}B(p,αγ){sup 7}Be and {sup 10}B(p,p{sup ′}γ){sup 10}B reactions using two thin targets. The γ-rays emitted at E{sub γ}=429 and 718 keV respectively, were detected by four HPGe detectors placed on a motorized turntable. The overall systematic uncertainty of the measurements was estimated to be ∼8% while the statistical errors did not exceed 5%. The validity of the obtained cross sections was tested by performing a thick target benchmarking experiment. The results of the present work are compared with existing ones from literature and possible explanations for the observed differences are discussed.

  4. Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

    Science.gov (United States)

    Aguilar, M.; Alcaraz, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Azzarello, P.; Basile, M.; Barao, F.; Barreira, G.; Bartoloni, A.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bindi, V.; Boella, G.; Boschini, M.; Bourquin, M.; Bruni, G.; Buénerd, M.; Burger, J. D.; Burger, W. J.; Cai, X. D.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cernuda, I.; Chang, Y. H.; Chen, H. F.; Chen, H. S.; Chen, Z. G.; Chernoplekov, N. A.; Chiueh, T. H.; Choi, Y. Y.; Cindolo, F.; Commichau, V.; Contin, A.; Cortina-Gil, E.; Crespo, D.; Cristinziani, M.; Dai, T. S.; dela Guia, C.; Delgado, C.; Di Falco, S.; Djambazov, L.; D'Antone, I.; Dong, Z. R.; Duranti, M.; Engelberg, J.; Eppling, F. J.; Eronen, T.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P. H.; Flügge, G.; Fouque, N.; Galaktionov, Y.; Gervasi, M.; Giovacchini, F.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W. Q.; Haino, S.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Hungerford, W.; Ionica, M.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kim, D. H.; Kim, G. N.; Kim, K. S.; Kirn, T.; Klimentov, A.; Kossakowski, R.; Kounine, A.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lechanoine-Leluc, C.; Lee, M. W.; Lee, S. C.; Levi, G.; Lin, C. H.; Liu, H. T.; Lu, G.; Lu, Y. S.; Lübelsmeyer, K.; Luckey, D.; Lustermann, W.; Maña, C.; Margotti, A.; Mayet, F.; McNeil, R. R.; Menichelli, M.; Mihul, A.; Mujunen, A.; Natale, S.; Oliva, A.; Palmonari, F.; Paniccia, M.; Park, H. B.; Park, W. H.; Pauluzzi, M.; Pauss, F.; Pereira, R.; Perrin, E.; Pevsner, A.; Pilo, F.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Pohl, M.; Produit, N.; Quadrani, L.; Rancoita, P. G.; Rapin, D.; Ren, D.; Ren, Z.; Ribordy, M.; Riihonen, E.; Ritakari, J.; Ro, S.; Roeser, U.; Sagdeev, R.; Santos, D.; Sartorelli, G.; Saouter, P.; Sbarra, C.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shin, J. W.; Shoumilov, E.; Shoutko, V.; Siedenburg, T.; Siedling, R.; Son, D.; Song, T.; Spada, F. R.; Spinella, F.; Steuer, M.; Sun, G. S.; Suter, H.; Tang, X. W.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Tornikoski, M.; Torsti, J.; Trümper, J.; Ulbricht, J.; Urpo, S.; Valtonen, E.; Vandenhirtz, J.; Velikhov, E.; Verlaat, B.; Vetlitsky, I.; Vezzu, F.; Vialle, J. P.; Viertel, G.; Vité, D.; Von Gunten, H.; Waldmeier Wicki, S.; Wallraff, W.; Wang, J. Z.; Wiik, K.; Williams, C.; Wu, S. X.; Xia, P. C.; Xu, S.; Xu, Z. Z.; Yan, J. L.; Yan, L. G.; Yang, C. G.; Yang, J.; Yang, M.; Ye, S. W.; Zhang, H. Y.; Zhang, Z. P.; Zhao, D. X.; Zhou, F.; Zhou, Y.; Zhu, G. Y.; Zhu, W. Z.; Zhuang, H. L.; Zichichi, A.; Zimmermann, B.; Zuccon, P.

    2011-08-01

    The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be), and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.

  5. Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

    CERN Document Server

    Aguilar, M; Wiik, K; Grimm, O; Sartorelli, G; Zhou, Y; Pauss, F; Alpat, B; Capell, M; Djambazov, L; Yang, M; Yang, J; Extermann, P; Arefiev, A; Zhuang, H L; Hermel, V; Mihul, A; Galaktionov, Y; Park, H B; Von Gunten, H; Vetlitsky, I; Zhou, F; Vandenhirtz, J; Ambrosi, G; Suter, H; Becker, U; Zhang, H Y; Alcaraz, J; Casaus, J; Ren, Z; Fiandrini, E; Hungerford, W; Ren, D; Wicki, S W; Eppling, F J; Flugge, G; Karlamaa, K; Boella, G; Levi, G; Choi, Y Y; Laborie, G; Lubelsmeyer, K; Gervasi, M; Kirn, T; Azzarello, P; Kounine, A; Barreira, G; Yan, L G; Burger, W J; Koutsenko, V; Grandi, D; Ribordy, M; Gu, W Q; Bindi, V; Favier, J; Haino, S; Shin, J W; Mana, C; Seo, E S; Plyaskin, V; Shoumilov, E; Cannarsa, P; Xia, P C; Ionica, M; Jongmanns, M; Shoutko, V; Wallraff, W; Margotti, A; Lee, S C; Giovacchini, F; Schael, S; Bourquin, M; Roeser, U; Lu, Y S; Torsti, J; Kossakowski, R; Chang, Y H; Menichelli, M; Verlaat, B; Paniccia, M; Steuer, M; Fouque, N; Boschini, M; Zimmermann, B; Song, T; Zuccon, P; Contin, A; Produit, N; Laitinen, T; Kim, K S; Viertel, G; Lin, C H; Lechanoine-Leluc, C; Delgado, C; Lu, G; Pohl, M; Yang, C G; Tornikoski, M; Duranti, M; Cindolo, F; Xu, S; Lebedev, A; Xu, Z Z; Crespo, D; Cristinziani, M; Tomassetti, N; Kim, D H; Biland, A; Bertucci, B; Trumper, J; Buenerd, M; Hangarter, K; Kenney, G; Quadrani, L; Hofer, H; Berdugo, J; Siedenburg, T; Chen, Z G; Ting, S M; Vezzu, F; Cortina-Gil, E; Dai, T S; Barao, F; Commichau, V; Zhang, Z P; Sun, G S; Zhu, W Z; Laurenti, G; Chen, H S; Kim, G N; Sagdeev, R; Wu, S X; Urpo, S; Lee, M W; Rapin, D; Kraeber, M; Chen, H F; Engelberg, J; Ritakari, J; Di Falco, S; Zhu, G Y; Vite, D; Ulbricht, J; Bruni, G; Bellagamba, L; Williams, C; Fisher, P H; D'Antone, I; Pevsner, A; Castellini, G; Chernoplekov, N A; Ao, L; Giusti, P; McNeil, R R; Allaby, J; Yan, J L; Son, D; Santos, D; Cai, X D; Rancoita, P G; Becker, R; Wang, J Z; Oliva, A; Karpinski, W; Cernuda, I; Saouter, P; Ro, S; Anderhub, H; Dela Guia, C; Schwering, G; Ting, S C C; Lamanna, G; Pauluzzi, M; Berges, P; Riihonen, E; Pojidaev, V; Chiueh, T H; Valtonen, E; Pereira, R; Spinella, F; Perrin, E; Park, W H; Dong, Z R; Zichichi, A; Battiston, R; von Dratzig, A S; Vialle, J P; Klimentov, A; Liu, H T; Bartoloni, A; Arruda, L; Tang, X W; Mujunen, A; Pimenta, M; Casadei, D; Spada, F R; Eronen, T; Mayet, F; Palmonari, F; Lustermann, W; Velikhov, E; Pilo, F; Zhao, D X; Luckey, D; Basile, M; Sbarra, C; Natale, S; Siedling, R; Ye, S W; Burger, J D

    2011-01-01

    The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios (2)H/(4)He, (3)He/(4)He, (6)Li/(7)Li, (7)Be/((9)Be+(10)Be), and (10)B/(11)B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June.

  6. Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

    OpenAIRE

    Aguilar, M.; Alcaraz, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; P. Azzarello(c); Basile, M.; Barao, F.; G. Barreira(LIP Lisboa); Bartoloni, A; Battiston, R.

    2011-01-01

    The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be), and 10B/11B in the range 0.2–1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91...

  7. 17 CFR 240.10b5-2 - Duties of trust or confidence in misappropriation insider trading cases.

    Science.gov (United States)

    2010-04-01

    ... in misappropriation insider trading cases. 240.10b5-2 Section 240.10b5-2 Commodity and Securities... Devices and Contrivances § 240.10b5-2 Duties of trust or confidence in misappropriation insider trading... of insider trading under Section 10(b) of the Act and Rule 10b-5. The law of insider trading...

  8. Bare astrophysical S(E)-factor for the {sup 6}Li(d, {alpha}){sup 4}He and {sup 7}Li(p, {alpha}){sup 4}He reactions at astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzone, R.G.; Spitaleri, C.; Lattuada, M.; Musumarra, A.; Pellegriti, M.G.; Romano, S.; Tumino, A.; Cherubini, S.; Figuera, P.; Miljanic, D.; Rolfs, C.; Typel, S.; Wolter, H.H.; Castellani, V.; Degl' Innocenti, S.; Imperio, A

    2003-05-05

    The Trojan Horse Method has been applied to study the {sup 7}Li(p, {alpha}){sup 4}He and {sup 6}(Li(d, {alpha}){sup 4}He reactions through the {sup 7}Li(d, {alpha}{alpha})n and {sup 6}Li({sup 6}Li, {alpha}{alpha}){sup 4}He three body processes, respectively. The electron screening potential deduced from these experiments is much larger than the adiabatic approximation prediction for both cases; the systematic discrepancy between data and theoretical predictions is thus confirmed. Astrophysical implications of these measurements are also discussed.

  9. Clusters in neutron-rich light nuclei

    Directory of Open Access Journals (Sweden)

    Jelavić Malenica D.

    2016-01-01

    Full Text Available Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states, but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.

  10. Effects of Wnt-10b on proliferation and differentiation of murine melanoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Misu, Masayasu [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ouji, Yukiteru, E-mail: oujix@naramed-u.ac.jp [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Kawai, Norikazu [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nishimura, Fumihiko [Department of Neurosurgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nakamura-Uchiyama, Fukumi [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Yoshikawa, Masahide, E-mail: myoshika@naramed-u.ac.jp [Department of Pathogen, Infection and Immunity, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan)

    2015-08-07

    In spite of the strong expression of Wnt-10b in melanomas, its role in melanoma cells has not been elucidated. In the present study, the biological effects of Wnt-10b on murine B16F10 (B16) melanoma cells were investigated using conditioned medium from Wnt-10b-producing COS cells (Wnt-CM). After 2 days of culture in the presence of Wnt-CM, proliferation of B16 melanoma cells was inhibited, whereas tyrosinase activity was increased. An in vitro wound healing assay demonstrated that migration of melanoma cells to the wound area was inhibited with the addition of Wnt-CM. Furthermore, evaluation of cellular senescence revealed prominent induction of SA-β-gal-positive senescent cells in cultures with Wnt-CM. Finally, the growth of B16 melanoma cell aggregates in collagen 3D-gel cultures was markedly suppressed in the presence of Wnt-CM. These results suggest that Wnt-10b represses tumor cell properties, such as proliferation and migration of B16 melanoma cells, driving them toward a more differentiated state along a melanocyte lineage. - Highlights: • Wnt-10b inhibited proliferation and migration of melanoma cells. • Wnt-10b induced tyrosinase activity and senescence of melanoma cells. • Wnt-10b suppressed growth of cell aggregates in collagen 3D-gel cultures. • Wnt-10b represses tumor cell properties, driving them toward a more differentiated state along a melanocyte lineage.

  11. Without salt, the 'thermophilic' protein Mth10b is just mesophilic.

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    Full Text Available Most proteins from thermophiles or hyperthermophiles are intrinsically thermostable. However, though Methanobacterium thermoautotrophicum ΔH is a thermophilic archaeon with an optimal growth temperature of 65 °C, Mth10b, an atypical member the Sac10b protein family from M. thermoautotrophicum ΔH, seems not intrinsically thermostable. In this work, to clarify the molecular mechanism of Mth10b remaining stable under its physiological conditions, the thermodynamic properties of Mth10b were studied through equilibrium unfolding experiments performed at pH 7.0 monitored by circular dichroism (CD spectra in detail. Our work demonstrated that Mth10b is not intrinsically thermostable and that due to the masking effect upon the large numbers of destabilizing electrostatic repulsions resulting from the extremely uneven distribution of charged residues over the surface of Mth10b, salt can contribute to the thermostability of Mth10b greatly. Considering that the intracellular salt concentration is high to 0.7 M, we concluded that salt is the key extrinsic factor to Mth10b remaining stable under its physiological conditions. In other word, without salt, 'thermophilic' protein Mth10b is just a mesophilic one.

  12. Production of secondary particles and nuclei in cosmic rays collisions with the interstellar gas using the FLUKA code

    Science.gov (United States)

    Mazziotta, M. N.; Cerutti, F.; Ferrari, A.; Gaggero, D.; Loparco, F.; Sala, P. R.

    2016-08-01

    The measured fluxes of secondary particles produced by the interactions of Cosmic Rays (CRs) with the astronomical environment play a crucial role in understanding the physics of CR transport. In this work we present a comprehensive calculation of the secondary hadron, lepton, gamma-ray and neutrino yields produced by the inelastic interactions between several species of stable or long-lived cosmic rays projectiles (p, D, T, 3He, 4He, 6Li, 7Li, 9Be, 10Be, 10B, 11B, 12C, 13C, 14C, 14N, 15N, 16O, 17O, 18O, 20Ne, 24Mg and 28Si) and different target gas nuclei (p, 4He, 12C, 14N, 16O, 20Ne, 24Mg, 28Si and 40Ar). The yields are calculated using FLUKA, a simulation package designed to compute the energy distributions of secondary products with large accuracy in a wide energy range. The present results provide, for the first time, a complete and self-consistent set of all the relevant inclusive cross sections regarding the whole spectrum of secondary products in nuclear collisions. We cover, for the projectiles, a kinetic energy range extending from 0.1 GeV/n up to 100 TeV/n in the lab frame. In order to show the importance of our results for multi-messenger studies about the physics of CR propagation, we evaluate the propagated spectra of Galactic secondary nuclei, leptons, and gamma rays produced by the interactions of CRs with the interstellar gas, exploiting the numerical codes DRAGON and GammaSky. We show that, adopting our cross section database, we are able to provide a good fit of a complete sample of CR observables, including: leptonic and hadronic spectra measured at Earth, the local interstellar spectra measured by Voyager, and the gamma-ray emissivities from Fermi-LAT collaboration. We also show a set of gamma-ray and neutrino full-sky maps and spectra.

  13. Wnt10b 诱导再生毛囊的表达特性研究%Expression characteristics in regenerating hair follicles induced by Wnt10b

    Institute of Scientific and Technical Information of China (English)

    星懿展; 郭海英; 马小艮; 李玉红

    2016-01-01

    目的:研究 Wnt10b 诱导再生毛囊的表达特性及诱导作用机制。方法 HEK-293细胞内扩增并用氯化铯梯度离心纯化 Wnt10b 过表达腺病毒及对照腺病毒,皮内注射至 C57BL/6J 小鼠背部皮肤,在处理后2.5、5、7、9、14、28 d 时取材,HE 染色及免疫组化染色观察毛囊结构特征、信号通路表达特征及增殖特性。结果HE 染色发现,AdWnt10b 处理组从第5天开始出现新生毛囊结构,正常生长,第28天左右进入退化期。免疫组化染色发现,AdWnt10b 处理组从处理后5 d 开始新生毛囊具有 AE15表达,随着毛囊生长而增加,至处理后28 d开始减少。在 AdWnt10b 处理后5 d,观察到β连环素的核表达,Lef1特异性表达于毛芽和毛母质部位,且全为核表达。在 AdWnt10b 处理后28 d,Lef1表达减弱。AdWnt10b 处理后2.5 d 即可见 Ki67表达于表皮和毛囊外根鞘。处理后2.5、7、9、14 d 均在隆突区见到 Ki67的表达;从处理后7 d 开始,Ki67表达于毛母质细胞。结论Wnt10b 诱导的再生毛囊具有正常的毛囊结构,Wnt10b 激活了经典 Wnt 信号通路,其作用的靶细胞是毛囊干细胞及其子代细胞。%Objective To investigate expression characteristics in regenerating hair follicles induced by Wnt10b, and to explore mechanisms underlying Wnt10b-induced regeneration of hair follicles. Methods Both adenovirus containing the Wnt10b gene(AdWnt10b)and that containing the green fluorescent protein-encoding gene(AdGFP)were amplified in HEK-293 cells and purified by caesium chloride density gradient centrifugation. A total of 36 C57BL/6J mice were randomly and equally divided into the AdWnt10b group and AdGFP group to be intracutaneously injected with AdWnt10b and AdGFP on the back respectively. Three mice were sacrificed on day 2.5, 5, 7, 9, 14 and 28 after the injection separately, and skin samples were resected from the injected sites subsequently. Hematoxylin and

  14. All-optical production of dual Bose-Einstein condensates of paired fermions and bosons with 6Li and 7Li

    Science.gov (United States)

    Ikemachi, Takuya; Ito, Aki; Aratake, Yukihito; Chen, Yiping; Koashi, Masato; Kuwata-Gonokami, Makoto; Horikoshi, Munekazu

    2017-01-01

    We report the first all-optical production of dual Bose-Einstein condensates (BECs) of paired 6Li (fermion) and one spin state of 7Li (boson) at the magnetic field where the s-wave interactions between fermions are resonant. Fermions are cooled efficiently by evaporative cooling and they serve as coolant for bosons. As a result, the dual condensates can be achieved by using a simple experimental apparatus and procedures, as in the case of the all-optical production of a single BEC. We show that the all-optical method enables us to realize variety of ultracold Bose-Fermi mixtures.

  15. Cross-section measurements for {sup 239}Pu(n,f) and {sup 6}Li(n,{alpha}) with a lead slowing-down spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rochman, D. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)]. E-mail: drochman@bnl.gov; Haight, R.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: haight@lanl.gov; O' Donnell, J.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: odonnell@lanl.gov; Wender, S.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: wender@lanl.gov; Vieira, D.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: vieira@lanl.gov; Bond, E.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: bond@lanl.gov; Bredeweg, T.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: toddb@lanl.gov; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: j_wilhelmy@lanl.gov; Granier, T. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: granier@cea.fr; Ethvignot, T. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: ethvignot@cea.fr; Petit, M. [Commissariat a l' Energie Atomique, 91680 Bruyeres-le-Chatel (France)]. E-mail: petit@cea.fr; Danon, Y. [Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)]. E-mail: danony@rpi.edu; Romano, C. [Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)]. E-mail: romanc2@rpi.edu

    2006-08-01

    We present fission cross-section measurements with {approx}10ng of {sup 239}Pu performed using the LANSCE Lead Slowing-Down Spectrometer. Results of Li6(n,{alpha}) measurements with a sample size of 760ng of {sup 6}Li are also reported. This technical achievement demonstrates the feasibility of measuring neutron-induced fission cross-section on samples with 10ng of fissile actinides that are available on ultra-small quantities. Furthermore, results on neutron-induced alpha emission show that measurements for astrophysics purposes are feasible with the LSDS.

  16. Cross-section measurements for 239Pu(n,f) and 6Li(n, α) with a lead slowing-down spectrometer

    Science.gov (United States)

    Rochman, D.; Haight, R. C.; O'Donnell, J. M.; Wender, S. A.; Vieira, D. J.; Bond, E. M.; Bredeweg, T. A.; Wilhelmy, J. B.; Granier, T.; Ethvignot, T.; Petit, M.; Danon, Y.; Romano, C.

    2006-08-01

    We present fission cross-section measurements with ˜10 ng of 239Pu performed using the LANSCE Lead Slowing-Down Spectrometer. Results of Li6(n,α) measurements with a sample size of 760 ng of 6Li are also reported. This technical achievement demonstrates the feasibility of measuring neutron-induced fission cross-section on samples with 10 ng of fissile actinides that are available on ultra-small quantities. Furthermore, results on neutron-induced alpha emission show that measurements for astrophysics purposes are feasible with the LSDS.

  17. Search for $^6_\\Lambda$H hypernucleus by the $^6$Li$(\\pi^-,K^+)$ reaction at $p_{\\pi^-}$ = 1.2 GeV/$c$

    CERN Document Server

    Sugimura, H; Ahn, J K; Ajimura, S; Akazawa, Y; Amano, N; Aoki, K; Bhang, H C; Chiga, N; Endo, M; Evtoukhovitch, P; Feliciello, A; Fujioka, H; Fukuda, T; Hasegawa, S; Hayakawa, S; Honda, R; Hosomi, K; Hwang, S H; Ichikawa, Y; Igarashi, Y; Imai, K; Ishibashi, N; Iwasaki, R; Joo, C W; Kiuchi, R; Lee, J K; Lee, J Y; Matsuda, K; Matsumoto, Y; Matsuoka, K; Miwa, K; Mizoi, Y; Moritsu, M; Nagae, T; Nagamiya, S; Nakagawa, M; Naruki, M; Noumi, H; Ota, R; Roy, B J; Saha, P K; Sakaguchi, A; Sako, H; Samanta, C; Samoilov, V; Sasaki, Y; Sato, S; Sekimoto, M; Shimizu, Y; Shiozaki, T; Shirotori, K; Soyama, T; Takahashi, T; Takahashi, T N; Tamura, H; Tanabe, K; Tanaka, T; Tanida, K; Tokiyasu, A O; Tsamalaidze, Z; Ukai, M; Yamamoto, T O; Yamamoto, Y; Yang, S B; Yoshida, K

    2014-01-01

    We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_{\\Lambda}$H, by the $^6$Li($\\pi^-,K^+$) reaction at $p_{\\pi^-}$ =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 $^6_{\\Lambda}$H hypernucleus neither below nor above the $^4_{\\Lambda}$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_{\\Lambda}$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

  18. Measurements of double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li for 18 MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo; Sanami, Toshiya; Win, T.; Miura, Takako; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1997-03-01

    Double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li were measured for 18 MeV neutrons at Tohoku University 4.5 MV Dynamitron facility. Neutron emission spectra were obtained down to 1 MeV at 13 angles with energy resolution good enough to separate discrete levels. A care was taken to eliminate the sample-dependent background due to parasitic neutrons. Experimental results were in fair agreement with the JENDL-3.2 data and a simple model considering a three-body breakup process and discrete level excitations. (author)

  19. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    OpenAIRE

    Mosset, J. -B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2015-01-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC^4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC^4 filter has been emulated digitally. The dete...

  20. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    Science.gov (United States)

    Mosset, J.-B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  1. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    CERN Document Server

    Mosset, J -B; Greuter, U; Hildebrandt, M; Schlumpf, N

    2015-01-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC^4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC^4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  2. Utilization of Boron (10B derived from fertilizer by sugar cane Aproveitamento do Boro (10B proveniente do fertilizante pela cana-de-açúcar

    Directory of Open Access Journals (Sweden)

    Henrique Coutinho Junqueira Franco

    2009-12-01

    Full Text Available The response to B in agricultural systems of sugar cane is still an unexplored issue; B application has however recently been widely publicized and used with a certain degree of frequency. The use of 10B-labeled fertilizers may further contribute to clarify this practice. With the objective of evaluating sugar cane use of B (10B derived from fertilizer (boric acid, an experiment was conducted under field conditions in the 2005/2006 growing season. The experiment consisted of the installation of microplots (2 x 1.5 m where 4 kg ha-1 B (boric acid with 85.95 % in 10B atoms dissolved in water was applied 90 days after planting (May 2005. The solution was applied to the soil on both sides of the plant row at a distance of 20 cm. After harvest (June 2006 the B content and 10B abundance in % atoms in all parts of the sugar cane plants (stalks, dry leaves, tips and roots were determined. Results showed that the total B accumulated was 471 g ha-1 in the entire plant (35 % in the stalks, 22 % in the dry leaves, 9 % in the tips and 34 % in the roots. The sugar cane plants used on average 14 % of the total accumulated B in the above-ground part (44 g ha-1 and 11 % in the roots (19 g ha-1, totaling 13 % in the entire plant (63 g ha-1. The recovery of 10B-fertilizer by sugar cane plants was low, around 2 % of the total applied amount.No agrossistema da cana-de-açúcar a resposta à aplicação de B é ainda uma questão não esclarecida, porém é um procedimento que vem sendo utilizado com certa frequência. O uso de fertilizantes marcados com 10B pode auxiliar no entendimento dessa prática. Com o objetivo de avaliar o aproveitamento do B (10B proveniente do fertilizante (ácido bórico pela cana-de-açúcar, realizou-se um experimento em campo, na safra de 2005/2006, que consistiu na instalação de microparcelas (2 m de comprimento por 1,5 de largura, que, após 90 dias do plantio (maio de 2005, receberam 4 kg ha-1 de B (ácido bórico com 85,95 % em

  3. No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, B R; Vary, J P; Nogga, A; Navratil, P; Ormand, W E

    2004-01-08

    The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.

  4. Evaluation of the Westinghouse 10B depletion for BWR control rods

    Energy Technology Data Exchange (ETDEWEB)

    Vallgren, Christina

    2008-03-15

    The aim of this work was to establish the 10B depletion model for CR 99 control rods by using the latest version of POLCA7. In order to obtain an understanding of the differences between the currently used 10B depletion models implemented in POLCA4 at O3 and in SIMULATE-3 at OL1, and the latest improved model implemented in the latest POLCA7, this work has been performed in three different parts. The first part of the work was to find out how large differences there exist in 10B depletion between the calculated data by using the latest core monitoring system (POLCA7 version 4.10.0) and the measured data obtained in the hot-cell laboratory in Studsvik. It was found that the 10B depletion computed by the latest POLCA7 version is in good agreement with the measured data from Studsvik. A poor agreement with a conservative overestimation in 10B depletion was also found between the old model and the measured data. The aim of the second part of the work was to compare the calculated 10B depletion values for two CR 99 rods from Olkiluoto 1 with the calculated 10B depletion value for a CR 99 rod from Oskarshamn 3, by using the new 10B depletion model implemented in the latest POLCA7 version. Swelling measurements of the boron carbide pins, used as absorber material, have indicated that the 10B depletion should be of similar magnitude for the rods in Olkiluoto 1 and the rod in Oskarshamn 3, whereas the calculated values by using the earlier 10B depletion models on the process computers showed a difference of about 20 %. By using the new 10B depletion model m POLCA7, it was found that the 10B depletion in the two studied cases was similar to each other and, thus, the hypothesis of a linear relationship between B{sub 4}C swelling and thermal neutron fluence was supported. This third part of the work was carried out at KKL, Switzerland, and focused on comparing the B depletion models used in Westinghouse/POLCA7 and KKL/PRESTO-2. It was found that there is a slight difference in

  5. Measurement of differential cross sections and cross sections of the 6Li(n, t)4He reaction in the 1-2MeV energy range%1-2 MeV能区6Li(n,t)4He反应微分截面与截面的实验测量

    Institute of Scientific and Technical Information of China (English)

    张国辉; 陈金象; 唐国有; Gledenov Yu M; Sedysheva M; Khuukhenkhuu G

    2006-01-01

    利用屏栅电离室对1.05、1.54及2.25 MeV中子6Li(n,t)4He反应的微分截面与截面进行了实验测量.采用氚固体靶的T(p,n)3He反应产生准单能中子,用相对效率已知的BF3长中子管和238U裂变片相结合来测定绝对中子通量.将测量结果与已有数据进行了比较,1-2 MeV能区6Li(n,t)4He反应截面的分歧在一定程度上得到了澄清.

  6. Natural Abundance 17O, 6Li NMR and Molecular Modeling Studies of the Solvation Structures of Lithium bis(fluorosulfonyl)imide/1,2-dimethoxyethane Liquid Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Chuan; Hu, Mary Y.; Borodin, Oleg; Qian, Jiangfeng; Qin, Zhaohai; Zhang, Jiguang; Hu, Jian Z.

    2016-03-01

    Natural abundance 17O and 6Li NMR experiments, quantum chemistry and molecular dynamics studies were employed to investigate the solvation structures of Li+ at various concentrations of LiFSI in DME electrolytes in an effort to solve this puzzle. It was found that the chemical shifts of both 17O and 6Li changed with the concentration of LiFSI, indicating the changes of solvation structures with concentration. For the quantum chemistry calculations, the coordinated cluster LiFSI(DME)2 forms at first, and its relative ratio increases with increasing LiFSI concentration to 1 M. Then the solvation structure LiFSI(DME) become the dominant component. As a result, the coordination of forming contact ion pairs between Li+ and FSI- ion increases, but the association between Li+ and DME molecule decreases. Furthermore, at LiFSI concentration of 4 M the solvation structures associated with Li+(FSI-)2(DME), Li+2(FSI-)(DME)4 and (LiFSI)2(DME)3 become the dominant components. For the molecular dynamics simulation, with increasing concentration, the association between DME and Li+ decreases, and the coordinated number of FSI- increases, which is in perfect accord with the DFT results. These results provide more insight on the fundamental mechanism on the very high CE of Li deposition in these electrolytes, especially at high current density conditions.

  7. Simultaneous sub-Doppler laser cooling of fermionic $^6$Li and $^{40}$K on the D$_1$ line: Theory and Experiment

    CERN Document Server

    Sievers, Franz; Kretzschmar, Norman; Fernandes, Diogo Rio; Suchet, Daniel; Rabinovic, Michael; Parker, Colin V; Khaykovich, Lev; Salomon, Christophe; Chevy, Frédéric

    2014-01-01

    We report on simultaneous sub-Doppler laser cooling of fermionic $^6$Li and $^{40}$K using the D$_1$ optical transitions. We compare experimental results to a numerical simulation of the cooling process applying a semi-classical Monte Carlo wavefunction method. The simulation takes into account the three dimensional optical molasses setup and the dipole interaction between atoms and the bichromatic light field driving the D$_1$ transitions. We discuss the physical mechanisms at play, we identify the important role of coherences between the ground state hyperfine levels and compare D$_1$ and D$_2$ sub-Doppler cooling. In 5 ms, the D$_1$ molasses phase largely reduces the temperature for both $^6$Li and $^{40}$K at the same time, with a final temperature of 44 $\\mu$K and 11 $\\mu$K, respectively. For both species this leads to a phase-space density close to $10^{-4}$. These conditions are well suited to directly load an optical or magnetic trap for efficient evaporative cooling to quantum degeneracy.

  8. Parsec-scale Variations in the 7Li i/6Li i Isotope Ratio Toward IC 348 and the Perseus OB 2 Association

    Science.gov (United States)

    Knauth, D. C.; Taylor, C. J.; Ritchey, A. M.; Federman, S. R.; Lambert, D. L.

    2017-01-01

    Measurements of the lithium isotopic ratio in the diffuse interstellar medium from high-resolution spectra of the Li i λ6708 resonance doublet have now been reported for a number of lines of sight. The majority of the results for the 7Li/6Li ratio are similar to the solar system ratio of 12.2, but the line of sight toward o Per, a star near the star-forming region IC 348, gave a ratio of about two, the expected value for gas exposed to spallation and fusion reactions driven by cosmic rays. To examine the association of IC 348 with cosmic rays more closely, we measured the lithium isotopic ratio for lines of sight to three stars within a few parsecs of o Per. One star, HD 281159, has 7Li/6Li ≃ 2 confirming production by cosmic rays. The lithium isotopic ratio toward o Per and HD 281159 together with published analyses of the chemistry of interstellar diatomic molecules suggest that the superbubble surrounding IC 348 is the source of the cosmic rays. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  9. An ultracold neutron (UCN) detector with Ti/ sup 6 LiF multi-layer converter and sup 5 sup 8 Ni reflector

    CERN Document Server

    Maier-Komor, P; Bergmaier, A; Dollinger, G; Paul, S; Petzoldt, G; Schott, W

    2002-01-01

    High efficient detectors for ultracold neutrons (UCN) must be developed for the new high flux neutron source Forschungsreaktor Muenchen II (FRM II). On silicon PIN diodes 76 mu g/cm sup 2 sup 5 sup 8 Ni was deposited as a UCN reflector. On this 100 double layers of sup n sup a sup t Ti (4.7 mu g/cm sup 2) and sup 6 LiF (1.8 mu g/cm sup 2) were deposited to function as a UCN converter. On top of this, 33 double layers of sup n sup a sup t Ti (3.4 mu g/cm sup 2) and sup 6 LiF (0.92 mu g/cm sup 2) were condensed in addition to provide sensitivity to very low-energy UCN. Finally, 6.0 mu g/cm sup 2 sup n sup a sup t V was deposited to protect the multi-layers. Vanadium has nearly zero optical potential for UCN and thus should not hinder their transmission. Since no expensive isotopes were involved, a source to substrate distance of 24 cm could be chosen, leading to excellent uniformity. The setup designed for deposition under ultrahigh vacuum conditions and the evaporation procedures are described.

  10. Simultaneous measurement of angular distribution of elastic scattering for {sup 6}Li, {sup 7}Be, and {sup 8}B in {sup 58}Ni; Medida simultanea de Distribuciones Angulares de Dispersion Elastica para {sup 6}Li, {sup 7}Be, y {sup 8}B en {sup 58}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz S, A. [Facultad de Ciencias, UAEM, Toluca, Estado de Mexico (Mexico); Martinez Q, E.; Aguilera R, E.F.; Murillo O, G.; Lizcano C, D.; Gomez C, A. [Departamento de Aceleradores, ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The experimental angular distributions of elastic scattering for the projectiles {sup 6}Li, {sup 7}Be, {sup 8}B in {sup 58}Ni were obtained. Using the Optical model with a Woods-Saxon potential form, as much for the real part as for the imaginary one, an adjustment to the experimental data varying only the depth of the imaginary part of the potential is made. A comparison of the results obtained for each projectile is made. (Author)

  11. A point mutation in the gene for asparagine-linked glycosylation 10B (Alg10b) causes nonsyndromic hearing impairment in mice (Mus musculus).

    Science.gov (United States)

    Probst, Frank J; Corrigan, Rebecca R; Del Gaudio, Daniela; Salinger, Andrew P; Lorenzo, Isabel; Gao, Simon S; Chiu, Ilene; Xia, Anping; Oghalai, John S; Justice, Monica J

    2013-01-01

    The study of mouse hearing impairment mutants has led to the identification of a number of human hearing impairment genes and has greatly furthered our understanding of the physiology of hearing. The novel mouse mutant neurological/sensory 5 (nse5) demonstrates a significantly reduced or absent startle response to sound and is therefore a potential murine model of human hearing impairment. Genetic analysis of 500 intercross progeny localized the mutant locus to a 524 kilobase (kb) interval on mouse chromosome 15. A missense mutation in a highly-conserved amino acid was found in the asparagine-linked glycosylation 10B gene (Alg10b), which is within the critical interval for the nse5 mutation. A 20.4 kb transgene containing a wildtype copy of the Alg10b gene rescued the mutant phenotype in nse5/nse5 homozygous animals, confirming that the mutation in Alg10b is responsible for the nse5/nse5 mutant phenotype. Homozygous nse5/nse5 mutants had abnormal auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), and cochlear microphonics (CMs). Endocochlear potentials (EPs), on the other hand, were normal. ABRs and DPOAEs also confirmed the rescue of the mutant nse5/nse5 phenotype by the wildtype Alg10b transgene. These results suggested a defect in the outer hair cells of mutant animals, which was confirmed by histologic analysis. This is the first report of mutation in a gene involved in the asparagine (N)-linked glycosylation pathway causing nonsyndromic hearing impairment, and it suggests that the hearing apparatus, and the outer hair cells in particular, are exquisitely sensitive to perturbations of the N-linked glycosylation pathway.

  12. A point mutation in the gene for asparagine-linked glycosylation 10B (Alg10b causes nonsyndromic hearing impairment in mice (Mus musculus.

    Directory of Open Access Journals (Sweden)

    Frank J Probst

    Full Text Available The study of mouse hearing impairment mutants has led to the identification of a number of human hearing impairment genes and has greatly furthered our understanding of the physiology of hearing. The novel mouse mutant neurological/sensory 5 (nse5 demonstrates a significantly reduced or absent startle response to sound and is therefore a potential murine model of human hearing impairment. Genetic analysis of 500 intercross progeny localized the mutant locus to a 524 kilobase (kb interval on mouse chromosome 15. A missense mutation in a highly-conserved amino acid was found in the asparagine-linked glycosylation 10B gene (Alg10b, which is within the critical interval for the nse5 mutation. A 20.4 kb transgene containing a wildtype copy of the Alg10b gene rescued the mutant phenotype in nse5/nse5 homozygous animals, confirming that the mutation in Alg10b is responsible for the nse5/nse5 mutant phenotype. Homozygous nse5/nse5 mutants had abnormal auditory brainstem responses (ABRs, distortion product otoacoustic emissions (DPOAEs, and cochlear microphonics (CMs. Endocochlear potentials (EPs, on the other hand, were normal. ABRs and DPOAEs also confirmed the rescue of the mutant nse5/nse5 phenotype by the wildtype Alg10b transgene. These results suggested a defect in the outer hair cells of mutant animals, which was confirmed by histologic analysis. This is the first report of mutation in a gene involved in the asparagine (N-linked glycosylation pathway causing nonsyndromic hearing impairment, and it suggests that the hearing apparatus, and the outer hair cells in particular, are exquisitely sensitive to perturbations of the N-linked glycosylation pathway.

  13. Probing the Statistical Decay and α-clustering effects in 12C + 12C and 14N + 10B reactions

    Science.gov (United States)

    Morelli, L.; Baiocco, G.; D'Agostino, M.; Bruno, M.; Gulminelli, F.; Cinausero, M.; Degerlier, M.; Fabris, D.; Gramegna, F.; Marchi, T.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Lopez, A.; Pasquali, G.; Piantelli, S.; Valdrè, S.

    2014-03-01

    An experimental campaign has been undertaken at Laboratori Nazionali di Legnaro (LNL INFN), Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. On the experimental side, a first reaction: 12C+12C at 95 MeV beam energy has been measured, using the GARFIELD + Ring Counter (RCo) apparatuses. Fusion-evaporation events have been exclusively selected out of the entire data set. The comparison to a dedicated Hauser-Feshbach calculation allows us to give constraints on the nuclear level density at high excitation energy for light systems ranging from C up to Mg. Out-of-equilibrium aα emission has been evidenced and attributed both to an entrance channel effect (favoured by the cluster nature of reaction partners), and, in more dissipative events, to the persistence of cluster correlations well above the 24Mg threshold for 6 α's decay. In order to study the same 24Mg compound nucleus at similar excitation energy with respect to this first reaction a new measurement, 14N + 10B at 5.7 A.MeV, was performed at LNL laboratories with the same experimental setup. The comparison between the two systems would allow us to further constrain the level density of light nuclei in the mass-excitation energy range of interest. In this perspective, deviations from a statistical behaviour can be used as a tool to get information on nuclear clustering, both in the ground-state for projectile and target and in the hot source formed in the collision.

  14. Probing the Statistical Decay and α-clustering effects in 12C + 12C and 14N + 10B reactions

    Directory of Open Access Journals (Sweden)

    Morelli L.

    2014-03-01

    Full Text Available An experimental campaign has been undertaken at Laboratori Nazionali di Legnaro (LNL INFN, Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. On the experimental side, a first reaction: 12C+12C at 95 MeV beam energy has been measured, using the GARFIELD + Ring Counter (RCo apparatuses. Fusion-evaporation events have been exclusively selected out of the entire data set. The comparison to a dedicated Hauser-Feshbach calculation allows us to give constraints on the nuclear level density at high excitation energy for light systems ranging from C up to Mg. Out-of-equilibrium aα emission has been evidenced and attributed both to an entrance channel effect (favoured by the cluster nature of reaction partners, and, in more dissipative events, to the persistence of cluster correlations well above the 24Mg threshold for 6 α’s decay. In order to study the same 24Mg compound nucleus at similar excitation energy with respect to this first reaction a new measurement, 14N + 10B at 5.7 A.MeV, was performed at LNL laboratories with the same experimental setup. The comparison between the two systems would allow us to further constrain the level density of light nuclei in the mass-excitation energy range of interest. In this perspective, deviations from a statistical behaviour can be used as a tool to get information on nuclear clustering, both in the ground-state for projectile and target and in the hot source formed in the collision.

  15. Utilization of Boron (10B) derived from fertilizer by sugar cane

    OpenAIRE

    2009-01-01

    The response to B in agricultural systems of sugar cane is still an unexplored issue; B application has however recently been widely publicized and used with a certain degree of frequency. The use of 10B-labeled fertilizers may further contribute to clarify this practice. With the objective of evaluating sugar cane use of B (10B) derived from fertilizer (boric acid), an experiment was conducted under field conditions in the 2005/2006 growing season. The experiment consisted of the installatio...

  16. Quarks in finite nuclei

    CERN Document Server

    Guichon, P A M; Thomas, A W

    1996-01-01

    We describe the development of a theoretical description of the structure of finite nuclei based on a relativistic quark model of the structure of the bound nucleons which interact through the (self-consistent) exchange of scalar and vector mesons.

  17. Using the Doppler broadened γ line of the 10B(n,αγ)7Li reaction for thermal neutron detection

    Science.gov (United States)

    Ben-Galim, Y.; Wengrowicz, U.; Moreh, R.; Orion, I.; Raveh, A.

    2016-02-01

    When a thermal neutron is absorbed by 10B in the 10B(n,α)7Li reaction, there is a chance of 94% that a 478 keV photon be emitted by an excited 7Li nucleus. This reaction is exothermic with a Q-value of 2.31 MeV and the nuclei are emitted with kinetic energies of E(α)=1.47 MeV and E(7Li*)=0.84 MeV. This implies that the 478 keV γ line is emitted by a moving 7Li nucleus and hence is expected to be Doppler broadened. In the present work we suggest to use this broadening of the γ line as a fingerprint for the detection of thermal neutrons using a high resolution gamma spectrometer. We thus developed a Monte Carlo program using a MATLAB code based on a High Purity Germanium (HPGe) detector coupled with a Boron Carbide (B4C) sheet to calculate the γ line broadening. Our simulation shows that the FWHM width of the resulting γ line is 12.6 keV, in good agreement with our measurement. Hence the broadened γ line emitted by the 10B(n,αγ)7Li reaction and detected by a HPGe detector shows that this method is an effective tool for neutron detection while maintaining good gamma discrimination.

  18. Angular Distribution and Cross Section Measurement of the 6Li(3He,n8B Reaction at 5.8 MeV

    Directory of Open Access Journals (Sweden)

    Cinausero M.

    2014-03-01

    Full Text Available The reaction 6Li(3He,n8B was studied at Laboratori Nazionali di Legnaro in the framework of the EUROnu Design Study for a Beta Beam facility at CERN. The 8B production cross section was determined through neutron angular distribution by using the time-of-flight technique. Thanks to the high statistics achieved, the neutron angular distribution for the population of the 8B first excited state has been measured for the first time. Discrepancies with other available data sets for 8B ground state population are discussed and interpreted in the framework of DWBA calculations. Further measurements at beam energies above 10 MeV are needed to clarify the behaviour of the angular distribution

  19. Two-stage magneto-optical trapping and narrow-line cooling of $^6$Li atoms to high phase-space density

    CERN Document Server

    Sebastian, Jimmy; Li, Ke; Gan, Huat Chai Jaren; Li, Wenhui; Dieckmann, Kai

    2014-01-01

    We report an experimental study of peak and phase-space density of a two-stage magneto-optical trap (MOT) of 6-Li atoms, which exploits the narrower $2S_{1/2}\\rightarrow 3P_{3/2}$ ultra-violet (UV) transition at 323 nm following trapping and cooling on the more common D2 transition at 671 nm. The UV MOT is loaded from a red MOT and is compressed to give a high phase-space density up to $3\\times 10^{-4}$. Temperatures as low as 33 $\\mu$K are achieved on the UV transition. We study the density limiting factors and in particular find a value for the light-assisted collisional loss coefficient of $1.3 \\pm0.4\\times10^{-10}\\,\\textrm{cm}^3/\\textrm{s}$ for low repumping intensity.

  20. Detector for the FSD Fourier-Diffractometer Based on ZnS(Ag)/^{6}LiF Scintillation Screen and Wavelength Shifting Fibers Readout

    CERN Document Server

    Kuzmin, E S; Bokuchava, G D; Zhuk, V V; Kudryashov, V A; Buklin, A P; Trounov, V A

    2001-01-01

    At the IBR-2 pulsed reactor (FLNP, JINR, Dubna), a specialized time-of-flight instrument Fourier-Stress-Diffractometer (FSD) intended for the measurement of internal steresses in bulk samples by using high-resolution neutron diffraction is under construction. One of the main components of the diffractometer is a new-type detector with combined electronic - geometrical focusing uniting a large solid angle and a small geometry contribution to the instrumental resolution. The first two modules of the detector, based on scintillation screen ZnS(Ag)/^{6}LiF with wavelength shifting fibers readout have been developed and tested. The design of the detector and associated electronics are described. The method of time focusing surface approximation, using the screen flexibility is proposed. Characteristics of tested modules in comparison with a detector of previous generation are presented and advantages of new detector design for high-resolution diffractometry are discussed.

  1. Probing the statistical decay and alpha-clustering effects in 12c+12c and 14n+10b reactions

    CERN Document Server

    Morelli, Luca; Agostino, M D; Bruno, M; Gulminelli, F; Cinausero, M; Degerlier, M; Fabris, D; Gramegna, F; Marchi, T; Barlini, S; Bini, M; Casini, G; Gelli, N; Lopez, A; Pasquali, G; Piantelli, S; Valdre', S

    2013-01-01

    An experimental campaign has been undertaken at INFN Laboratori Nazionali di Legnaro, Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. A first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation allows us to give constraints on the nuclear level density at high excitation energy for light systems ranging from C up to Mg. Out-of-equilibrium emission has been evidenced and attributed both to entrance channel effects favoured by the cluster nature of reaction partners and, in more dissipative events, to the persistence of cluster correlations well above the 24Mg threshold for 6 alphas decay. The 24Mg compound nucleus has been studied with a new measurement 14N + 10B at 5.7 AM...

  2. A new study of {sup 10}B(p,α){sup 7}Be reaction at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Caciolli, A.; Depalo, R. [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); INFN, Sezione di Padova, Padova (Italy); Broggini, C.; Menegazzo, R. [INFN, Sezione di Padova, Padova (Italy); La Cognata, M.; Puglia, S.M.R.; Sergi, M.L. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Lamia, L. [Universita degli Studi di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Mou, L.; Rigato, V.; Rossi Alvarez, C. [Laboratori Nazionali di Legnaro, INFN, Legnaro (Italy); Romano, S.; Spitaleri, C. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Universita degli Studi di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Tumino, A. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Universita degli Studi di Enna ' ' Kore' ' , Facolta di Ingegneria e Architettura, Enna (Italy)

    2016-05-15

    The {sup 10}B(p,α){sup 7}Be reaction is of great interest since it has many applications in different fields of research such as nuclear astrophysics, nuclear physics, and models of new reactors for clean energy generation. This reaction has been studied at the AN2000 accelerator of the INFN National Laboratories of Legnaro (LNL). The total cross section has been measured in a wide energy range (250-1182 keV) by using the activation method. The decays of the {sup 7}Be nuclei produced by the reaction were measured at the low counting facility of LNL by using two fully shielded high-purity germanium detectors. The present dataset shows a large discrepancy with respect to one of the previous data at the same energies and reduces the total uncertainty to the level of 6%. An R-matrix calculation has been performed on the present data using the parameters from previous Trojan Horse measurements for the 10 and 500 keV resonances. The present data do not lay on the R-matrix fit in one point suggesting the existence of a {sup 11}C level not observed yet. Further nuclear investigations are needed to confirm this hypothesis. (orig.)

  3. Human glioma growth is controlled by microRNA-10b.

    Science.gov (United States)

    Gabriely, Galina; Yi, Ming; Narayan, Ravi S; Niers, Johanna M; Wurdinger, Thomas; Imitola, Jaime; Ligon, Keith L; Kesari, Santosh; Esau, Christine; Stephens, Robert M; Tannous, Bakhos A; Krichevsky, Anna M

    2011-05-15

    MicroRNA (miRNA) expression profiling studies revealed a number of miRNAs dysregulated in the malignant brain tumor glioblastoma. Molecular functions of these miRNAs in gliomagenesis are mainly unknown. We show that inhibition of miR-10b, a miRNA not expressed in human brain and strongly upregulated in both low-grade and high-grade gliomas, reduces glioma cell growth by cell-cycle arrest and apoptosis. These cellular responses are mediated by augmented expression of the direct targets of miR-10b, including BCL2L11/Bim, TFAP2C/AP-2γ, CDKN1A/p21, and CDKN2A/p16, which normally protect cells from uncontrolled growth. Analysis of The Cancer Genome Atlas expression data set reveals a strong positive correlation between numerous genes sustaining cellular growth and miR-10b levels in human glioblastomas, while proapoptotic genes anticorrelate with the expression of miR-10b. Furthermore, survival of glioblastoma patients expressing high levels of miR-10 family members is significantly reduced in comparison to patients with low miR-10 levels, indicating that miR-10 may contribute to glioma growth in vivo. Finally, inhibition of miR-10b in a mouse model of human glioma results in significant reduction of tumor growth. Altogether, our experiments validate an important role of miR-10b in gliomagenesis, reveal a novel mechanism of miR-10b-mediated regulation, and suggest the possibility of its future use as a therapeutic target in gliomas. ©2011 AACR

  4. Parameters of Fermi-motion from Quasielastic Backward Pion-Proton Scattering on Nuclei

    CERN Document Server

    Abramov, B M; Dukhovskoy, I A; Khanov, A I; Krestnikov, Yu S; Krutenkova, A P; Kulikov, V V; Matsuk, M A; Radkevich, I A; Turdakina, E N

    1999-01-01

    In experiment on the study of the quasielastic pion-proton scattering at large momentum transfer on nuclei the proton Fermi-momentum distributions have been analysed in plane-wave approximation for light nuclei $^6$Li, $^7$Li and $^{12}$C. It was found that, contrary to (e,e') experiments, that the oscillator model gives slightly better description of our data than the Fermi - gas model. But the values of parameters of the distributions obtained in our analysis are considerably smaller, than in (e,e') experiments. It gives evidence that the plane-wave approximation is not sufficient and more complicated theoretical models which take into account the effects of distortion of pion-nucleon amplitude in a nuclear medium are necessary for analysis of our data.

  5. Using the Doppler broadened γ line of the {sup 10}B(n,αγ){sup 7}Li reaction for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Galim, Y., E-mail: ybgx3@walla.com [Department of Nuclear Engineering, Ben Gurion University (BGU) of the Negev (Israel); Wengrowicz, U. [Department of Nuclear Engineering, Ben Gurion University (BGU) of the Negev (Israel); NRC-Negev, P.O. Box 9001, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben Gurion University (BGU) of the Negev, Beer-Sheva 84105 (Israel); Orion, I. [Department of Nuclear Engineering, Ben Gurion University (BGU) of the Negev (Israel); Raveh, A. [Advanced Coatings Center at Rotem Industries Ltd., MishorYamin D.N. Arava 86800 (Israel)

    2016-02-21

    When a thermal neutron is absorbed by {sup 10}B in the {sup 10}B(n,α){sup 7}Li reaction, there is a chance of 94% that a 478 keV photon be emitted by an excited {sup 7}Li nucleus. This reaction is exothermic with a Q-value of 2.31 MeV and the nuclei are emitted with kinetic energies of E(α)=1.47 MeV and E({sup 7}Li*)=0.84 MeV. This implies that the 478 keV γ line is emitted by a moving {sup 7}Li nucleus and hence is expected to be Doppler broadened. In the present work we suggest to use this broadening of the γ line as a fingerprint for the detection of thermal neutrons using a high resolution gamma spectrometer. We thus developed a Monte Carlo program using a MATLAB code based on a High Purity Germanium (HPGe) detector coupled with a Boron Carbide (B{sub 4}C) sheet to calculate the γ line broadening. Our simulation shows that the FWHM width of the resulting γ line is 12.6 keV, in good agreement with our measurement. Hence the broadened γ line emitted by the {sup 10}B(n,αγ){sup 7}Li reaction and detected by a HPGe detector shows that this method is an effective tool for neutron detection while maintaining good gamma discrimination. - Highlights: • Thermal neutron detection by measuring the Doppler broadened 478 keV γ line from the {sup 10}B(n,αγ){sup 7}Li interaction. • Natural Boron Carbide coupled with a HPGe detector were used in this study. • A mathematical Monte-Carlo model for the suggested detector was introduced. • A calibration tool for the suggested detector is introduced. • Experimental results show that the suggested method can be used for neutron detection.

  6. Analysis of 10B by PIGE with factor analytical gamma-ray peak identification.

    Science.gov (United States)

    Savolainen, S; Räisänen, J; Eteläniemi, V; Abo Ramadan, U A; Kallio, M

    1995-09-01

    Studying the biodistribution of boronated compounds for B neutron capture therapy (BNCT) requires the accurate detection of low levels of boron (10B) in biological samples. Proton induced gamma-ray emission analysis (PIGE) of 10B was found to be viable in a study of low density lipoprotein (LDL), in tissue and blood samples. However, the method is sensitive to Na present in the samples and can therefore not be used for accurate measurements of 10B concentrations below 5 ppm in samples containing Na. PIGE can be considered to be an appropriate reference method for chemical B analysis. The factor analytical method presented here is the most objective way to separate Na and B peaks from each other, and the factorizing method can be applied in different forms of spectral analysis.

  7. Modulating hair follicle size with Wnt10b-DKK1 pair during hair regeneration

    Science.gov (United States)

    Lei, Mingxing; Guo, Haiying; Qiu, Weiming; Lai, Xiangdong; Yang, Tian; Widelitz, Randall B.; Chuong, Cheng-Ming; Lian, Xiaohua; Yang, Li

    2015-01-01

    Hair follicles have characteristic sizes corresponding to their cycle specific stage. However, how the anagen hair follicle specifies its size remains elusive. Here, we show that in response to prolonged ectopic Wnt10b-mediated β-catenin activation, regenerating anagen hair follicles grow larger in size. In particular, the hair bulb, dermal papilla and hair shaft become enlarged. While the formation of different hair types (Guard, Awl, Auchene, and Zigzag) is unaffected. Interestingly, we found the effect of exogenous WNT10b was mainly on Zigzag and less on the other kinds of hairs. We observed dramatically enhanced proliferation within the matrix, DP and hair shaft of the enlarged AdWnt10b-treated hair follicles compared with those of normal hair follicles at P98. Furthermore, expression of CD34, a specific hair stem cell marker, was increased in its number to the bulge region after AdWnt10b treatment. Ectopic expression of CD34 throughout the ORS region was also observed. Many CD34 positive hair stem cells were actively proliferating in AdWnt10b-induced hair follicles. Importantly, subsequent co-treatment with the Wnt inhibitor, DKK1, reduced hair follicle enlargement, decreased proliferation and maintained proper hair stem cell localization. Moreover, injection of DKK1 during early anagen significantly reduced the width of prospective hairs. Together, these findings strongly suggest that a balance of Wnt10b/DKK1 governs reciprocal signaling between cutaneous epithelium and mesenchyme to regulate proper hair follicle size. PMID:24750467

  8. Absolute efficiency measurements with the {sup 10}B based Jalousie detector

    Energy Technology Data Exchange (ETDEWEB)

    Modzel, G., E-mail: modzel@physi.uni-heidelberg [Physikalisches Institut, Universität Heidelberg, Neuenheimer Feld 226, 69120 Heidelberg (Germany); Henske, M. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8–10, 69123 Heidelberg (Germany); Houben, A. [Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany); Klein, M. [Physikalisches Institut, Universität Heidelberg, Neuenheimer Feld 226, 69120 Heidelberg (Germany); CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8–10, 69123 Heidelberg (Germany); Köhli, M.; Lennert, P. [Physikalisches Institut, Universität Heidelberg, Neuenheimer Feld 226, 69120 Heidelberg (Germany); Meven, M. [Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching (Germany); Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), Outstation at MLZ, 85747 Garching (Germany); Schmidt, C.J. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8–10, 69123 Heidelberg (Germany); GSI Detector Laboratory, Planckstr. 1, 64291 Darmstadt (Germany); Schmidt, U. [Physikalisches Institut, Universität Heidelberg, Neuenheimer Feld 226, 69120 Heidelberg (Germany); Schweika, W. [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), 52425 Jülich (Germany); European Spallation Source ESS AB, SE-22100 Lund (Sweden)

    2014-04-11

    The {sup 10}B based Jalousie detector is a replacement for {sup 3}He counter tubes, which are nowadays less affordable for large area detectors due to the {sup 3}He crisis. In this paper we investigate and verify the performance of the new {sup 10}B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75–50% for neutron energies of 10–100 meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17 Å (59 meV)

  9. Scattering Of Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Quaglioni, S; Navratil, P; Roth, R

    2009-12-15

    The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.

  10. Anharmonic vibrations in nuclei

    CERN Document Server

    Fallot, M; Andrés, M V; Catara, F; Lanza, E G; Scarpaci, J A; Chomaz, Ph.

    2003-01-01

    In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these two giant resonances on top of any state. Two-phonon energies are often lowered by one or two MeV because of the large matrix elements with such three phonon configurations. These effects are studied in two nuclei, 40Ca and 208Pb.

  11. The shapes of nuclei

    CERN Document Server

    Bertsch, G F

    2016-01-01

    Gerry Brown initiated some early studies on the coexistence of different nuclear shapes. The subject has continued to be of interest and is crucial for understanding nuclear fission. We now have a very good picture of the potential energy surface with respect to shape degrees of freedom in heavy nuclei, but the dynamics remain problematic. In contrast, the early studies on light nuclei were quite successful in describing the mixing between shapes. Perhaps a new approach in the spirit of the old calculations could better elucidate the character of the fission dynamics and explain phenomena that current theory does not model well.

  12. Magnetic signature of charge ordering in Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 and Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4

    CERN Document Server

    Verhoeven, V W J; Mulder, F M

    2002-01-01

    The stoichiometric compound LiMn sub 2 O sub 4 is known to show charge ordering with well-defined Mn sup 3 sup + and Mn sup 4 sup + sites just below room temperature (RT). Above RT the electrons are hopping rapidly between sites. For lithium-ion batteries the material Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 is technologically relevant. Due to the small amount of Li on the Mn site, the low-T regular ordering of the Mn charge appears to be destroyed completely, as is evidenced by neutron diffraction in the magnetically ordered state. However, the charges are still fixed in an irregular fashion, as can also be deduced from sup 7 Li nuclear magnetic resonance measurements. In the lithium-extracted compound Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 , predominantly Mn sup 4 sup + is present. Neutron diffraction in the magnetically ordered state shows a well-defined antiferromagnetic ordering, with doubling of the unit cell in three directions. Clear...

  13. 76 FR 12845 - Airworthiness Directives; APEX Aircraft Model CAP 10 B Airplanes

    Science.gov (United States)

    2011-03-09

    ... CAP 10 B Airplanes AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT... describes the unsafe condition as: A fatal accident occurred to a CAP 10C, in which the pilot lost control... specified products. The MCAI states: ] A fatal accident occurred to a CAP 10C, in which the pilot lost...

  14. Flow cytometer analysis of cell apoptosis of endometrial carcinoma with Wnt10b.

    Science.gov (United States)

    Zhou, Y; Zhao, X L; Guo, R X; Qiao, Y H; Zhang, X Y; Chen, Z H

    2016-01-01

    The aim of this study is to analyze the cell apoptosis of endometrial carcinoma (EC) with Wnt10b by Fluorescence Activated Cell Sorting (FACS) technology. AN3CA cell lines and Ishikawa-H-12 cell lines were taken as the in-vitro cell models to observe the influence of Wnt10b on key factors of Wnt signal pathway. Methyl thiazolyl tetrazolium (MTT) was applied for the detection of cell proliferation while FACS was used for the detection of cell apoptosis. Data were analyzed using statistical software SPSS14.0. After the overexpression of Wntl0b in AN3CA cells, the apoptosis rate dropped significantly compared with the two control groups (p < 0.05); while the apoptosis rate increased significantly compared with the control groups (p < 0.01) after Wntl0b knock-off in Ishikawa3-H-12 cells. In normal endometrium, Wnt10b gene expression was negative, while that in EC cells was positive. It can be concluded that Wnt10b gene can promote EC cell proliferation and inhibit its apoptosis.

  15. An investigation of the antinuclei and nuclei production mechanism in Pb + Pb collisions at 158-A-GeV

    Energy Technology Data Exchange (ETDEWEB)

    Arsenescu, R [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Baglin, C [CNRS-IN2P3, LAPP Annecy, F-74941 Annecy-le-Vieux (France); Beck, H P [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Borer, K [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Bussiere, A [CNRS-IN2P3, LAPP Annecy, F-74941 Annecy-le-Vieux (France); Elsener, K [CERN, SL Division, CH-1211 Geneva 23 (Switzerland); Gorodetzky, Ph [PCC - College de France, 11 Place Marcellin Berthelod, 75005 Paris, France (France); Guillaud, J P [CNRS-IN2P3, LAPP Annecy, F-74941 Annecy-le-Vieux (France); Kabana, S [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Klingenberg, R [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Lehmann, G [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Linden, T [Helsinki Institute of Physics, PO Box 9, FIN-00014 Helsinki (Finland); Lohmann, K D [CERN, SL Division, CH-1211 Geneva 23 (Switzerland); Mommsen, R [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Moser, U [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Pretzl, K [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Schacher, J [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Spiwoks, R [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland); Tuominiemi, J [Helsinki Institute of Physics, PO Box 9, FIN-00014 Helsinki (Finland); Weber, M [Laboratorium fuer Hochenergiephysik, Universitaet Bern, Sidlerstrasse 5, 3012-Bern (Switzerland)

    2003-11-01

    We investigate the production mechanisms of p, d, t, {sup 3}He, {sup 4}He, {sup 6}Li, pbar,dbar and {sup 3}Hebar in Pb+Pb collisions at 158-A-GeV measured near zero transverse momentum with the NA52 experiment at the CERN SPS. We find evidence that nuclei and antinuclei in Pb+Pb collisions are mainly produced via the coalescence mechanism out of a thermalized source of hadrons, at a time close to the thermal freeze-out of hadrons corresponding to a temperature of {approx}120-MeV.

  16. An investigation of the antinuclei and nuclei production mechanism in Pb + Pb collisions at 158 A GeV

    Science.gov (United States)

    Arsenescu, R.; Baglin, C.; Beck, H. P.; Borer, K.; Bussière, A.; Elsener, K.; Gorodetzky, Ph; Guillaud, J. P.; Kabana, S.; Klingenberg, R.; Lehmann, G.; Lindén, T.; Lohmann, K. D.; Mommsen, R.; Moser, U.; Pretzl, K.; Schacher, J.; Spiwoks, R.; Tuominiemi, J.; Weber, M.

    2003-11-01

    We investigate the production mechanisms of p, d, t, 3He, 4He, 6Li, \\overline {\\mathrm {p}} , \\overline {\\mathrm {d}} and \\overline {^3{\\mathrm {He}}} in Pb+Pb collisions at 158 A GeV measured near zero transverse momentum with the NA52 experiment at the CERN SPS. We find evidence that nuclei and antinuclei in Pb+Pb collisions are mainly produced via the coalescence mechanism out of a thermalized source of hadrons, at a time close to the thermal freeze-out of hadrons corresponding to a temperature of ~120 MeV.

  17. Elusive active galactic nuclei

    NARCIS (Netherlands)

    Maiolino, R; Comastri, A; Gilli, R; Nagar, NM; Bianchi, S; Boker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M

    2003-01-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically 'elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtai

  18. Utilization of boron ({sup 10}B) derived from fertilizer by sugar cane

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Henrique Coutinho Junqueira; Trivelin, Paulo Cesar Ocheuze, E-mail: hjfranco@cena.usp.b, E-mail: pcotrive@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Vitti, Andre Cesar, E-mail: acvitti@apta.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicaba, SP (Brazil). Polo Centro Sul; Otto, Rafael, E-mail: rotto@esalq.usp.b [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz; Faroni, Carlos Eduardo, E-mail: cfaroni@ctc.com.b [Centro de Tecnologia Canavieira (CTC), Piracicaba, SP (Brazil); Tovajar, Joao Gabriel, E-mail: jgtoaliari@bol.com.b [Cosan S.A., Valparaiso, SP (Brazil). Unidade Univalem

    2009-11-15

    The response to B in agricultural systems of sugar cane is still an unexplored issue; B application has however recently been widely publicized and used with a certain degree of frequency. The use of {sup 10}B-labeled fertilizers may further contribute to clarify this practice. With the objective of evaluating sugar cane use of B ({sup 10}B) derived from fertilizer (boric acid), an experiment was conducted under field conditions in the 2005/2006 growing season. The experiment consisted of the installation of microplots (2 x 1.5 m) where 4 kg ha{sup -1} B (boric acid with 85.95 % in {sup 10}B atoms) dissolved in water was applied 90 days after planting (May 2005). The solution was applied to the soil on both sides of the plant row at a distance of 20 cm. After harvest (June 2006) the B content and {sup 10}B abundance in % atoms in all parts of the sugar cane plants (stalks, dry leaves, tips and roots) were determined. Results showed that the total B accumulated was 471 g ha{sup -1} in the entire plant (35 % in the stalks, 22 % in the dry leaves, 9 % in the tips and 34 % in the roots). The sugar cane plants used on average 14 % of the total accumulated B in the above-ground part (44 g ha{sup -1}) and 11 % in the roots (19 g ha{sup -1}), totaling 13 % in the entire plant (63 g ha{sup -1}). The recovery of 10B-fertilizer by sugar cane plants was low, around 2 % of the total applied amount. (author)

  19. Preparation and characterization of (10)B boric acid with high purity for nuclear industry.

    Science.gov (United States)

    Zhang, Weijiang; Liu, Tianyu; Xu, Jiao

    2016-01-01

    Boric acid is often added into coolant as neutron capture agent for pressurized water reactor, whose amount is influenced by its abundance and purity. Therefore, the preparation of enriched (10)B boric acid with high purity is beneficial to nuclear industry. (10)B is also used in developing tumor-specific boronated drugs in boron neutron capture therapy. The boronated drug can be administered to patient intravenously, intratumorally, or deposited at tumor site in surgical excision. Thus, enriched (10)B boric acid is of practical significance in the field of medicine. Self-made boron trifluoride-methanol-complex solution was selected as one of the experimental reagents, and the preparation of (10)B acid was realized by one-step reaction for the complexes with water and calcium chloride. The determination of electrical conductivity in reaction process proves that the optimum reaction time was 16-20 h. Furthermore, the effect of reaction time, ratio of calcium chloride to complex as well as the amount of water on the purity and yield of boric acid was investigated. Finally, the optimum reaction time was 20 h, the optimal solid-liquid ratio (molar ratio) was 3:1, and the amount of water was 1 L of deionized water for each mol of the complex. H2O2 was added in the reaction process to remove Fe(2+). After recrystallization, IR spectra of (10)B boric acid was measured and compared with standard to verify the product of boric acid. The feasibility of the preparation method was determined by the detection of XRD of boric acid. To observe the morphology by polarizing microscope, crystal structure was obtained. The purity of the final product is 99.95 %, and the yield is 96.47 %. The ion concentration of boric acid accords with the national standard of high purity, which was determined by ICP.

  20. Elastic scattering and total reaction cross sections for {sup 8}B, {sup 7}Be and {sup 6}Li + {sup 12}C systems

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, J.C.; Barioni, A.; Guimaraes, V. [Universidade de Sao Paulo (USP), SP (Brazil); Paes, B.; Lubian, J. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Aguilera, E.F. [Instituto Nacional de Investigaciones Nucleares (Mexico); Kolata, J.J.; Roberts, A.L. [University of Notre Dame, Indiana (United States); Becchetti, F.D.; Villano, A.; Ojaruega, M.; Jing, H. [University of Michigan (United States)

    2011-07-01

    In this work we have measured angular distributions for the elastic scattering of {sup 8}B, {sup 7}Be and {sup 6}Li on {sup 12}C target at laboratory energies of 25.8 MeV, 18.8 MeV and 12.3 MeV, respectively. The optical model has been used for the analysis of such data using Woods-Saxon and Sao Paulo potentials. We also probed the effect of breakup on the elastic scattering of {sup 8}B+{sup 12}C as this mechanism may become important due to the low binding energy of this nucleus. This investigation was performed by means of coupled channels calculations and cluster folding potentials. This study is very interesting because there are few data on {sup 8}B elastic scattering. There are some of its elastic scattering on carbon target, but at higher energies, where it was not possible to get information on its halo peculiarities. Also, we present here the total reaction cross section obtained from the elastic scattering analysis and compared with other weakly and tightly bound projectiles on carbon target. (author)

  1. Pulse shape discrimination characteristics of stilbene crystal, pure and 6Li loaded plastic scintillators for a high resolution coded-aperture neutron imager

    Science.gov (United States)

    Cieślak, M. J.; Gamage, K. A. A.; Glover, R.

    2017-07-01

    Pulse shape discrimination performances of single stilbene crystal, pure plastic and 6Li loaded plastic scintillators have been compared. Three pulse shape discrimination algorithms have been tested for each scintillator sample, assessing their quality of neutron/gamma separation. Additionally, the digital implementation feasibility of each algorithm in a real-time embedded system was evaluated. Considering the pixelated architecture of the coded-aperture imaging system, a reliable method of simultaneous multi-channel neutron/gamma discrimination was sought, accounting for the short data analysis window available for each individual channel. In this study, each scintillator sample was irradiated with a 252Cf neutron source and a bespoke digitiser system was used to collect the data allowing detailed offline examination of the sampled pulses. The figure-of-merit was utilised to compare the discrimination quality of the collected events with respect to various discrimination algorithms. Single stilbene crystal presents superior neutron/gamma separation performance when compared to the plastic scintillator samples.

  2. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra

    NARCIS (Netherlands)

    Marashdeh, A.; Frankcombe, T.J.

    2008-01-01

    The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The dehydrog

  3. Shape Deformations in Atomic Nuclei

    CERN Document Server

    Hamamoto, Ikuko

    2011-01-01

    The ground states of some nuclei are described by densities and mean fields that are spherical, while others are deformed. The existence of non-spherical shape in nuclei represents a spontaneous symmetry breaking.

  4. Ultra High Energy Nuclei Propagation

    CERN Document Server

    Aloisio, Roberto

    2008-01-01

    We discuss the problem of ultra high energy nuclei propagation in astrophysical backgrounds. We present a new analytical computation scheme based on the hypothesis of continuos energy losses in a kinetic formulation of the particles propagation. This scheme enables the computation of the fluxes of ultra high energy nuclei as well as the fluxes of secondaries (nuclei and nucleons) produced by the process of photo-disintegration suffered by nuclei.

  5. Ternary Particles with Extreme N/z Ratios from Neutron-Induced Fission

    Science.gov (United States)

    Köster, Ulli; Faust, Herbert; Friedrichs, Thomas; Oberstedt, Stephan; Fioni, Gabriele; Groß, Martin; Ahmad, Irshad

    The following sections are included: * Introduction * Ternary fission models * Common parameterization * Experimental results * Yields of neutron-deficient nuclei * 3He * 6Li, 7Be and 10B * 15O * Yield of very neutron-rich nuclei * Suppression of halo nuclei? * Acknowledgements * References

  6. Fast isotopic separation of (10) B and (11) B boric acid by capillary zone electrophoresis.

    Science.gov (United States)

    Kamencev, Mikhail; Yakimova, Nina; Moskvin, Leonid; Kuchumova, Irina; Tkach, Kirill; Malinina, Yulia

    2016-11-01

    Fast isotopic separation of (10) B and (11) B boric acid by CZE was demonstrated. The BGE contained 25 mM phenylalanine and 5 mM putrescine (рН 8.95). The running conditions were +25 kV at 20°C with indirect photometric detection at 210 nm. Baseline separation was achieved in less than 9 min. RSD of migration times and corrected peak areas were less than 0.5 and 3%, respectively (n = 5). Linearity was demonstrated in the range 0.2-2 mM for (11) B and 0.2-0.5 mM for (10) B. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Study of the 10B ( p ,α)7Be reaction through the indirect Trojan Horse method

    Science.gov (United States)

    Puglia, S. M. R.; Spitaleri, C.; Lamia, L.; Romano, S.; Burjan, V.; Carlin, N.; Chengbo, L.; Del Santo, M. G.; Kroha, V.; Hons, Z.; Irgaziev, B.; La Cognata, M.; Mrazek, J.; Mukhamedzhanov, A.; Munhoz, M. G.; Pizzone, R. G.; Qungang, W.; Rapisarda, G. G.; Shu-Hua, Z.; Sergi, M. L.; Somoryai, E.; Souza, F.; Szanto de Toledo, A.; Tabacaru, G.; Tumino, A.; Wakabayashi, Y.; Yamaguchi, H.

    2015-02-01

    Boron abundances in stellar atmospheres, as well as berillium and lithium ones, can give useful hints for non-standard transport processes discrimination in stars. They can also be relevant for understanding several astrophysical processes (e.g. primordial nucleosynthesis and spallation reactions in ISM). A comprehensive study of Li Be B abundances can therefore confirm or not the presence of non-standard mixing processes in stellar envelopes. For this reason nuclear processes producing or depleting boron isotope abundance need to be studied at astrophysical energies. The 10B ( p ,α)7Be reaction has been studied by means of the Trojan Horse Method. The Trojan Horse Method was thus applied to the 10B ( d ,α7Be ) n reaction, studied at 24 MeV. The obtained results will be discussed.

  8. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  9. Bubble nuclei; Noyaux Bulles

    Energy Technology Data Exchange (ETDEWEB)

    Legoll, F. [Service de Physique Theorique, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1998-07-22

    For nuclei with very high electrical charge, the Coulomb field is expected to drive the protons away from the centre to the surface of the nucleus. Such a nucleus would be no more compact but look like a bubble. The goal of this work is to confirm this idea. We are interested in only the ground state of spherical nuclei. We use the Skyrme potential with the Sly4 parametrization to calculate the mean-field Hamiltonian. Paring correlations are described by a surface-active delta paring interaction. In its ground state the nucleus {sup A=900} X{sub Z=274} is shown to be a bubble. Another stable state is found with a little higher energy: it is also a bubble. (author) 11 refs., 18 figs., 33 tabs.

  10. Relation between (e, e') sum rules in {sup 6,7}Li and {sup 4}He nuclei: Experiment and cluster model

    Energy Technology Data Exchange (ETDEWEB)

    Efros, V.D. [National Research Center ' ' Kurchatov Institute' ' , Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Timchenko, I.S.; Buki, A.Yu. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkov (Ukraine)

    2016-09-15

    The sums over (e, e') spectra of {sup 6}Li and {sup 7}Li nuclei which correspond to the longitudinal sum rule are studied. It is suggested that due to the cluster structure of the lithium isotopes these sums may approximately be expressed in terms of such a sum pertaining to the α-particle. Calculation of these sums is performed in the framework of cluster models with antisymmetrization done with respect to all the nucleons. At momentum transfers higher than 0.8 fm{sup -1} the relations expressing the A = 6 or 7 sum in terms of the A = 4 sum prove to be valid with rather high accuracy. In the region of momentum transfers around 1 fm{sup -1} the longitudinal correlation functions of {sup 6}Li and {sup 7}Li nuclei are found to be close to that of the α-particle. Basing on this, the difference between the q values at which the high-q limit of the inelastic sum rule is reached in the {sup 6,7}Li cases and the {sup 4}He case is explained. The experimental longitudinal sums in the range between 0.450 and 1.625 fm{sup -1} are employed to perform comparison with the theoretical sum rule calculated in the framework of cluster models. Out of the experimental sums, those in the range between 0.750 and 1.000 fm{sup -1} in the {sup 6}Li case and between 0.750 and 1.125 fm{sup -1} in the {sup 7}Li case are obtained in the present work. In the {sup 6}Li case a complete agreement between experiment and the calculated sum rule is found while in the {sup 7}Li case an agreement only at a qualitative level is observed. (orig.)

  11. Symmetries in Nuclei

    CERN Document Server

    Van Isacker, P

    2010-01-01

    The use of dynamical symmetries or spectrum generating algebras for the solution of the nuclear many-body problem is reviewed. General notions of symmetry and dynamical symmetry in quantum mechanics are introduced and illustrated with simple examples such as the SO(4) symmetry of the hydrogen atom and the isospin symmetry in nuclei. Two nuclear models, the shell model and the interacting boson model, are reviewed with particular emphasis on their use of group-theoretical techniques.

  12. On Quasibound N* Nuclei

    CERN Document Server

    Kelkar, N G; Moskal, P

    2015-01-01

    The possibility for the existence of unstable bound states of the S11 nucleon resonance N$^*$(1535) and nuclei is investigated. These quasibound states are speculated to be closely related to the existence of the quasibound states of the eta mesons and nuclei. Within a simple model for the N N$^*$ interaction involving a pion and eta meson exchange, N$^*$-nucleus potentials for N*-$^3$He and N*-$^{24}$Mg are evaluated and found to be of a Woods-Saxon like form which supports two to three bound states. In case of N*-$^3$He, one state bound by only a few keV and another by 4 MeV is found. The results are however quite sensitive to the N N$^*$ $\\pi$ and N N$^*$ $\\eta$ vertex parameters. A rough estimate of the width of these states, based on the mean free path of the exchanged mesons in the nuclei leads to very broad states with $\\Gamma \\sim$ 80 and 110 MeV for N*-$^3$He and N*-$^{24}$Mg respectively.

  13. Coupled-channels effects in elastic scattering and near-barrier fusion induced by weakly bound nuclei and exotic halo nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Beck, C. [Institut Pluridisciplinaire Hubert Curien, UMR 7178, IN2P3-CNRS et Universite Louis Pasteur (Strasbourg I), 23 rue du Loess - BP28, F-67037 Strasbourg Cedex 2 (France); Keeley, N. [DSM/DAPNIA/SPhN CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Diaz-Torres, A. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

    2007-03-15

    The influence on fusion of coupling to the breakup process is investigated for reactions where at least one of the colliding nuclei has a sufficiently low binding energy for breakup to become an important process. Elastic scattering, excitation functions for sub-and near-barrier fusion cross sections, and breakup yields are analyzed for {sup 6,7}Li+{sup 59}Co. Continuum-Discretized Coupled-Channels (CDCC) calculations describe well the data at and above the barrier. Elastic scattering with {sup 6}Li (as compared to {sup 7}Li) indicates the significant role of breakup for weakly bound projectiles. A study of {sup 4,6}He induced fusion reactions with a three-body CDCC method for the {sup 6}He halo nucleus is presented. The relative importance of breakup and bound-state structure effects on total fusion is discussed. (authors)

  14. Genetic association study of WNT10B polymorphisms with BMD and adiposity parameters in Danish and Belgian males

    DEFF Research Database (Denmark)

    Van Camp, Jasmijn K; Beckers, Sigri; Zegers, Doreen;

    2013-01-01

    Because of the importance of the Wnt pathway in the development and maintenance of both adipose and bone tissue, we wanted to evaluate the involvement of WNT10B, a Wnt pathway activator, in adipogenesis and osteoblastogenesis in humans. Genetic association between WNT10B polymorphisms and adiposity...... a previously shown negative effect on BMD. No significant associations were observed in the SIBLOS population. In the present study, no association between WNT10B polymorphisms and adiposity parameters was found. However, our results clearly illustrate a role for WNT10B variants in determining human BMD...

  15. Skyrmions and Nuclei

    Science.gov (United States)

    Battye, R. A.; Manton, N. S.; Sutcliffe, P. M.

    We review recent work on the modelling of atomic nuclei as quantised Skyrmions, using Skyrme's original model with pion fields only. Skyrmions are topological soliton solutions, whose conserved topological charge B is identified with the baryon number of a nucleus. Apart from an energy and length scale, the Skyrme model has just one dimensionless parameter m, proportional to the pion mass. It has been found that a good fit to experimental nuclear data requires m to be of order 1. The Skyrmions for B up to 7 have been known for some time, and are qualitatively insensitive to whether m is zero or of order 1. However, for baryon numbers B = 8 and above, the Skyrmions have quite a compact structure for m of order 1, rather than the hollow polyhedral structure found when m = 0. One finds for baryon numbers which are multiples of four, that the Skyrmions are composed of B = 4 sub-units, as in the α-particle model of nuclei. The rational map ansatz gives a useful approximation to the Skyrmion solutions for all baryon numbers when m = 0. For m of order 1, it gives a good approximation for baryon numbers up to 7, and generalisations of this ansatz are helpful for higher baryon numbers. We briefly review the work from the 1980s and 90s on the semiclassical rigidbody quantisation of Skyrmions for B = 1, 2, 3 and 4. We then discuss more recent work extending this method to B = 6, 7, 8, 10 and 12. We determine the quantum states of the Skyrmions, finding their spins, isospins and parities, and compare with the experimental data on the ground and excited states of nuclei up to mass number 12.

  16. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  17. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  18. Visibility of comet nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ney, E.P.

    1982-01-22

    Photography of the nucleus of comet Halley is the goal of several planned space missions. The nucleus of a comet is surrounded by a cloud of dust particles. If this cloud is optically thick, it will prevent observation of the nuclear surface. Broadband photometry of nine comets has been analyzed to determine the visibility of their nuclei. Only in the case of comet West near perihelion was the dust dense enough to interfere with imaging. Comparison of the visual brightness of the well-observed comets with that of Halley in 1910 leads to the conclusion that the nucleus of Halley can be imaged without significant obscuration by the dust.

  19. Microscopic analysis of p^{10}B scattering at the intermediate energies

    CERN Document Server

    Dzhazairov-Kahramanov, Albert; Krassovitskiy, Pavel

    2016-01-01

    The differential cross sections of the p^{10}B scattering at energies of 197, 600 and 1000 MeV have been calculated within the framework of the Glauber theory. The operator of multiple scattering takes into account the contributions of single and double collisions. The contributions from protons scattering on the nucleons of different shells have been estimated in the single-scattering cross-section. The comparison with the experiment at 197 MeV and with DWBA calculation showed the adequate description of cross-sections in the region of the front angles.

  20. Mutation of the cytosolic ribosomal protein-encoding RPS10B gene affects shoot meristematic function in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Stirnberg Petra

    2012-09-01

    Full Text Available Abstract Background Plant cytosolic ribosomal proteins are encoded by small gene families. Mutants affecting these genes are often viable, but show growth and developmental defects, suggesting incomplete functional redundancy within the families. Dormancy to growth transitions, such as the activation of axillary buds in the shoot, are characterised by co-ordinated upregulation of ribosomal protein genes. Results A recessive mutation in RPS10B, one of three Arabidopsis genes encoding the eukaryote-specific cytoplasmic ribosomal protein S10e, was found to suppress the excessive shoot branching mutant max2-1. rps10b-1 mildly affects the formation and separation of shoot lateral organs, including the shoot axillary meristems. Axillary meristem defects are enhanced when rps10b-1 is combined with mutations in REVOLUTA, AUXIN-RESISTANT1, PINOID or another suppressor of max2-1, FAR-RED ELONGATED HYPOCOTYL3. In some of these double mutants, the maintenance of the primary shoot meristem is also affected. In contrast, mutation of ALTERED MERISTEM PROGRAMME1 suppresses the rps10b-1axillary shoot defect. Defects in both axillary shoot formation and organ separation were enhanced by combining rps10b-1 with cuc3, a mutation affecting one of three Arabidopsis NAC transcription factor genes with partially redundant roles in these processes. To assess the effect of rps10b-1 on bud activation independently from bud formation, axillary bud outgrowth on excised cauline nodes was analysed. The outgrowth rate of untreated buds was reduced only slightly by rps10b-1 in both wild-type and max2-1 backgrounds. However, rps10b-1 strongly suppressed the auxin resistant outgrowth of max2-1 buds. A developmental phenotype of rps10b-1, reduced stamen number, was complemented by the cDNA of another family member, RPS10C, under the RPS10B promoter. Conclusions RPS10B promotes shoot branching mainly by promoting axillary shoot development. It contributes to organ boundary

  1. Elusive Active Galactic Nuclei

    CERN Document Server

    Maiolino, R; Gilli, R; Nagar, N M; Bianchi, S; Böker, T; Colbert, E; Krabbe, A; Marconi, A; Matt, G; Salvati, M

    2003-01-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically "elusive". X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive AGN in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 10^24 cm^-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN, the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical Narrow Line Region. Elusive AGN may contribute significantly to the 30 keV bump of the X-ray background.

  2. Digital signal processing for a thermal neutron detector using ZnS(Ag):{sup 6}LiF scintillating layers read out with WLS fibers and SiPMs

    Energy Technology Data Exchange (ETDEWEB)

    Mosset, J.-B., E-mail: jean-baptiste.mosset@psi.ch; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-11

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):{sup 6}LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC{sup 4} filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC{sup 4} filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach. - Highlights: • Application of digital signal processing for a SiPM-based ZnS:6LiF neutron detector. • Optimisation of detector performances with 3 different digital filters. • Comparison with detector performances with a full analog signal processing.

  3. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    Toshimi Suda

    2014-11-01

    A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.

  4. Detection of the secondary eclipse of WASP-10b in the Ks-band

    CERN Document Server

    Cruz, Patricia; Lillo-Box, Jorge; Diaz, Marcos; Birkby, Jayne; López-Morales, Mercedes; Hodgkin, Simon; Fortney, Jonathan J

    2014-01-01

    WASP-10b, a non-inflated hot Jupiter, was discovered around a K-dwarf in a near circular orbit ($\\sim $$0.06$). Since its discovery in 2009, different published parameters for this system have led to a discussion about the size, density, and eccentricity of this exoplanet. In order to test the hypothesis of a circular orbit for WASP-10b, we have observed its secondary eclipse in the Ks-band, where the contribution of planetary light is high enough to be detected from the ground. Observations were performed with the OMEGA2000 instrument at the 3.5-meter telescope at Calar Alto (Almer\\'ia, Spain), in staring mode during 5.4 continuous hours, with the telescope defocused, monitoring the target during the expected secondary eclipse. A relative light curve was generated and corrected from systematic effects, using the Principal Component Analysis (PCA) technique. The final light curve was fitted using a transit model to find the eclipse depth and a possible phase shift. The best model obtained from the Markov Chai...

  5. Ab-initio calculation of the photonuclear cross section of $^{10}$B

    CERN Document Server

    Kruse, M K G; Johnson, C W

    2015-01-01

    We present for the first-time the photonuclear cross section of $^{10}$B calculated within the ab-initio No Core Shell Model framework. Realistic two-nucleon (NN) chiral forces up to next-to-next-to-next-order (N3LO), which have been softened by the similarity renormalization group method (SRG) to $\\lambda=2.02$ fm$^{-1}$, were utilized. The electric-dipole response function is calculated using the Lanczos method. The effects of the continuum were accounted for by including neutron escape widths derived from R-matrix theory. The calculated cross section agrees well with experimental data in terms of structure as well as in absolute peak height, $\\sigma_{\\rm max}=4.85~{\\rm mb}$ at photon energy $\\omega=23.61~{\\rm MeV}$, and integrated cross section $85.36\\, {\\rm MeV \\cdotp mb}$. We test the Brink hypothesis by calculating the electric-dipole response for the first five positive-parity states in $^{10}$B and verify that dipole excitations built upon the ground- and excited states have similar characteristics.

  6. {sup 10}B concentration evaluation in autoradiography images by optical density measurements

    Energy Technology Data Exchange (ETDEWEB)

    Portu, A., E-mail: portu@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, AC: C1033AAJ, Ciudad Autonoma de Buenos Aires (Argentina); Saint Martin, G., E-mail: gisaint@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina); Brandizzi, D., E-mail: brandizzi@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Laboratorio de Microespectrofotometria (LANAIS-MEF), CONICET-CNEA (Argentina); Bernaola, O.A., E-mail: bernaola@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)

    2011-12-15

    The quantification and analysis of the tracks forming the autoradiography image of a tissue section is essential for the measurement of particle emitter concentration and distribution (e.g. {sup 10}B) in the sample. Conventional counting techniques cannot be used when track density is high because of track overlapping. A densitometry supported by image analysis method suitable for these cases has been developed. Optical density measurements obtained for boron solutions of known concentrations showed a linear behavior in the range of concentrations under consideration. - Highlights: Black-Right-Pointing-Pointer A nuclear tracks quantification method was developed applying optical densitometry supported by image analysis. Black-Right-Pointing-Pointer It will provide information about {sup 10}B distribution in samples whose autoradiographies present high density of tracks. Black-Right-Pointing-Pointer A calibration curve for optical density versus boron concentration was constructed and applied to the analysis of boron-doped silicon wafers. Black-Right-Pointing-Pointer Results were compared with those from an individual counting technique, obtaining a good agreement.

  7. Observation of breakup transfer process for the bound states of {sup 16}O populated from {sup 12}C({sup 6}Li,d) reaction at 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, S.; Basu, C.; Thompson, I. J.; Sugathan, P.; Jhinghan, A.; Golda, K. S.; Babu, A.; Singh, D.; Ray, S.; Mitra, A. K. [Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata-700064 (India); Lawrence Livermore National Laboratory, L-414, Livermore CA 94551 (United States); Inter University Accelerator Centre, New Delhi 110067 (India); Physics Department, Ramkrishna Vivekananda University, Belur, Howrah (India); Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata-700064 (India)

    2012-10-20

    The deuteron angular distribution for the {sup 12}C({sup 6}Li,d){sup 16}O* has been measured at 20 MeV populating bound and unbound states of {sup 16}O. Analysis shows a dominance of breakup induced alpha transfer in comparison to a direct alpha transfer process for the bound states. The effect increases as the excitation energy of {sup 16}O decreases, maximizing at the ground state.

  8. Local chiral potentials and the structure of light nuclei

    CERN Document Server

    Piarulli, Maria; Schiavilla, Rocco; Kievsky, Alejandro; Lovato, Alessandro; Marcucci, Laura E; Pieper, Steven C; Viviani, Michele; Wiringa, Robert B

    2016-01-01

    We present fully local versions of the minimally non-local nucleon-nucleon potentials constructed in a previous paper [M.\\ Piarulli {\\it et al.}, Phys.\\ Rev.\\ C {\\bf 91}, 024003 (2015)], and use them in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of $^3$H, $^3$He, $^4$He, $^6$He, and $^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $\\Delta$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0--125 MeV or 0--200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutof...

  9. Improved Results on Extraction of 11B(p, α0)8Be and 10B(p, α)7Be S(E)-Factor Through the Trojan Horse Method

    Science.gov (United States)

    Puglia, S. M. R.; Lamia, L.; Romano, S.; Spitaleri, C.; Carlin, N.; Cherubini, S.; Del Santo, M. G.; Gulino, M.; Kroha, V.; Kubono, S.; La Cognata, M.; Li, C.; Pizzone, R. G.; Qungang, W.; Rapisarda, G. G.; Sergi, M. L.; Somoryai, E.; Souza, F.; Szanto de Toledo, A.; Tudisco, S.; Tumino, A.; Wakabayashi, Y.; Yamaguchi, H.

    2010-08-01

    In this work the analysis of the 10B(23p, α)7Be and 11B(p, α)8Be reactions, studied via the indirect Trojan Horse Method (THM), is discussed. In the astrophysical context of light nuclei LiBeB depletion, the above mentioned reactions are the main responsible for the destruction of boron in the stellar interior. The THM application allows their investigation in the astrophysically relevant energy region, around the Gamow Peak (~10 keV), overcoming the problems due to the presence of the Coulomb barrier and electron screening effect. The experimental procedure and the preliminary results are shown.

  10. MicroRNA-10b downregulation mediates acute rejection of renal allografts by derepressing BCL2L11

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoyou [Department of Organ Transplantation, Zhujiang Hospital, Guangzhou 510282 (China); Dong, Changgui [Institute of Molecular Ecology and Evolution, East China Normal University, Shanghai 200062 (China); Jiang, Zhengyao [Department of Organ Transplantation, Zhujiang Hospital, Guangzhou 510282 (China); Wu, William K.K. [Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); State Key Laboratory of Digestive Diseases, LKS Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Chan, Matthew T.V. [Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (China); Zhang, Jie [Department of Organ Transplantation, Zhujiang Hospital, Guangzhou 510282 (China); Li, Haibin; Qin, Ke [Guangxi Key Laboratory for Transplantation Medicine Department of Organ Transplantation in Guangzhou Military Region, Institute of Transplant Medicine, 303 Hospital of People' s Liberation Army, Nanning, Guangxi 530021 (China); Sun, Xuyong, E-mail: sunxuyong0528@163.com [Guangxi Key Laboratory for Transplantation Medicine Department of Organ Transplantation in Guangzhou Military Region, Institute of Transplant Medicine, 303 Hospital of People' s Liberation Army, Nanning, Guangxi 530021 (China)

    2015-04-10

    Kidney transplantation is the major therapeutic option for end-stage kidney diseases. However, acute rejection could cause allograft loss in some of these patients. Emerging evidence supports that microRNA (miRNA) dysregulation is implicated in acute allograft rejection. In this study, we used next-generation sequencing to profile miRNA expression in normal and acutely rejected kidney allografts. Among 75 identified dysregulated miRNAs, miR-10b was the most significantly downregulated miRNAs in rejected allografts. Transfecting miR-10b inhibitor into human renal glomerular endothelial cells recapitulated key features of acute allograft rejection, including endothelial cell apoptosis, release of pro-inflammatory cytokines (interleukin-6, tumor necrosis factor α, interferon-γ, and chemokine (C–C motif) ligand 2) and chemotaxis of macrophages whereas transfection of miR-10b mimics had opposite effects. Downregulation of miR-10b directly derepressed the expression of BCL2L11 (an apoptosis inducer) as revealed by luciferase reporter assay. Taken together, miR-10b downregulation mediates many aspects of disease pathogenicity of acute kidney allograft rejection. Restoring miR-10b expression in glomerular endothelial cells could be a novel therapeutic approach to reduce acute renal allograft loss. - Highlights: • miR-10b was the most downregulated microRNAs in acutely rejected renal allografts. • miR-10b downregulation triggered glomerular endothelial cell apoptosis. • miR-10b downregulation induced release of pro-inflammatory cytokines. • miR-10b downregulation derepressed its pro-apoptotic target BCL2L11.

  11. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  12. Gluon density in nuclei

    CERN Document Server

    Ayala, A P; Levin, E M

    1996-01-01

    In this talk we present our detail study ( theory and numbers) [1] on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather contraversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula [2] and estimate the value of the shadowing corrections in this case. Than we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus - nucleus cascade.

  13. Pulsars: Gigantic Nuclei

    CERN Document Server

    Xu, Renxin

    2011-01-01

    What is the real nature of pulsars? This is essentially a question of the fundamental strong interaction between quarks at low-energy scale and hence of the non-perturbative quantum chromo-dynamics, the solution of which would certainly be meaningful for us to understand one of the seven millennium prize problems (i.e., "Yang-Mills Theory") named by the Clay Mathematical Institute. After a historical note, it is argued here that a pulsar is very similar to an extremely big nucleus, but is a little bit different from the {\\em gigantic nucleus} speculated 80 years ago by L. Landau. The paper demonstrates the similarity between pulsars and gigantic nuclei from both points of view: the different manifestations of compact stars and the general behavior of the strong interaction.

  14. Nucleomorphs: enslaved algal nuclei.

    Science.gov (United States)

    Cavalier-Smith, T

    2002-12-01

    Nucleomorphs of cryptomonad and chlorarachnean algae are the relict, miniaturised nuclei of formerly independent red and green algae enslaved by separate eukaryote hosts over 500 million years ago. The complete 551 kb genome sequence of a cryptomonad nucleomorph confirms that cryptomonads are eukaryote-eukaryote chimeras and greatly illuminates the symbiogenetic event that created the kingdom Chromista and their alveolate protozoan sisters. Nucleomorph membranes may, like plasma membranes, be more enduring after secondary symbiogenesis than are their genomes. Partial sequences of chlorarachnean nucleomorphs indicate that genomic streamlining is limited by the mutational difficulty of removing useless introns. Nucleomorph miniaturisation emphasises that selection can dramatically reduce eukaryote genome size and eliminate most non-functional nuclear non-coding DNA. Given the differential scaling of nuclear and nucleomorph genomes with cell size, it follows that most non-coding nuclear DNA must have a bulk-sequence-independent function related to cell volume.

  15. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular, the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of this collective motions is a very good tool to understand the properties of the nucleus itself. The purpose of this article is to stress some aspects of these collective vibrations. We have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. Understanding of these phenomena remains one of the important subjects of actuality in the context of quantal systems in strong interaction. In particular, the study of the states with one or two vibration quanta provides a direct information on the structure of nuclei close to their ground states. Moreover, some collective states appear to be very robust against the onset of chaos. This is the case of the hot giant dipole built on top of a hot nucleus which seems to survive up to rather high temperatures. Their sudden disappearance is still a subject of controversy. It may be that the mean-field and the associated collective states are playing a crucial role also in catastrophic processes such as the phase-transitions. Indeed, when the system is diluted the collective vibrations may become unstable and it seems that these unstable modes provide a natural explanation to the self organization of the system in drops. Finally, considering the diversity of the different structures of exotic nuclei one may expect new vibration types. All these studies are showing the diversity of the collective motions of strongly correlated quantum systems such as the nucleus but many open questions remain to be solved. (authors) 304 refs., 53 figs., 5 tabs.

  16. (9)Be(d,n)(10)B-based neutron sources for BNCT.

    Science.gov (United States)

    Capoulat, M E; Herrera, M S; Minsky, D M; González, S J; Kreiner, A J

    2014-06-01

    In the frame of accelerator-based BNCT, the (9)Be(d,n)(10)B reaction was investigated as a possible source of epithermal neutrons. In order to determine the configuration in terms of bombarding energy, target thickness and Beam Shaping Assembly (BSA) design that results in the best possible beam quality, a systematic optimization study was carried out. From this study, the optimal configuration resulted in tumor doses ≥40Gy-Eq, with a maximum value of 51Gy-Eq at a depth of about 2.7cm, in a 60min treatment. The optimal configuration was considered for the treatment planning assessment of a real Glioblastoma Multiforme case. From this, the resulted dose performances were comparable to those obtained with an optimized (7)Li(p,n)-based neutron source, under identical conditions and subjected to the same clinical protocol.

  17. Tidal dissipation in a homogeneous spherical body. II. Three examples: Mercury, Io, and Kepler-10 b

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, Valeri V.; Efroimsky, Michael, E-mail: vvm@usno.navy.mil, E-mail: michael.efroimsky@usno.navy.mil [US Naval Observatory, 3450 Massachusetts Avenue NW, Washington, DC 20392 (United States)

    2014-11-01

    In Efroimsky and Makarov (Paper I), we derived from the first principles a formula for the tidal heating rate in a homogeneous sphere, compared it with the previously used formulae, and noted the differences. Now we present case studies: Mercury, Kepler-10 b, and a triaxial Io. A sharp frequency dependence of k {sub 2}/Q near spin-orbit resonances yields a sharp dependence of k {sub 2}/Q (and, therefore, of tidal heating) upon the spin rate. Thereby physical libration plays a major role in tidal heating of synchronously rotating planets. The magnitude of libration in the spin rate being defined by the planet's triaxiality, the latter becomes a factor determining the dissipation rate. Other parameters equal, a strongly triaxial synchronized body generates more heat than a similar body of a more symmetrical shape. After an initially triaxial object melts and loses its triaxiality, dissipation becomes less intensive; the body can solidify, with the tidal bulge becoming a new figure with triaxiality lower than the original. We derive approximate expressions for the dissipation rate in a Maxwell planet with the Maxwell time longer than the inverse tidal frequency. The expressions derived pertain to the 1:1 and 3:2 resonances and a nonresonant case; so they are applicable to most close-in super-Earths detected. In these planets, the heating outside synchronism is weakly dependent on the eccentricity and obliquity, provided both these parameters's values are moderate. According to our calculation, Kepler-10 b could hardly survive the intensive tidal heating without being synchronized, circularized, and reshaped through a complete or partial melt-down.

  18. Detection of the secondary eclipse of WASP-10b in the Ks-band

    Science.gov (United States)

    Cruz, Patricia; Barrado, David; Lillo-Box, Jorge; Diaz, Marcos; Birkby, Jayne; López-Morales, Mercedes; Hodgkin, Simon; Fortney, Jonathan J.

    2015-02-01

    Context. WASP-10b, a non-inflated hot Jupiter, was discovered around a K-dwarf in a near circular orbit (~0.06). Since its discovery in 2009, different published parameters for this system have led to a discussion about the size, density, and eccentricity of this exoplanet. Aims: In order to test the hypothesis of a circular orbit for WASP-10b, we observed its secondary eclipse in the Ks-band, where the contribution of planetary light is high enough to be detected from the ground. Methods: Observations were performed with the OMEGA2000 instrument at the 3.5 m telescope at Calar Alto (Almería, Spain), in staring mode during 5.4 continuous hours, with the telescope defocused, monitoring the target during the expected secondary eclipse. A relative light curve was generated and corrected from systematic effects, using the principal component analysis (PCA) technique. The final light curve was fitted using a transit model to find the eclipse depth and a possible phase shift. Results: The best model obtained from the Markov chain Monte Carlo analysis resulted in an eclipse depth of ΔF of 0.137%+0.013%-0.019% and a phase offset of Δφ of -0.0028 +0.0005-0.0004. The eclipse phase offset derived from our modeling has systematic errors that were not taken into account and should not be considered as evidence of an eccentric orbit. The offset in phase obtained leads to a value for | ecosω | of 0.0044. The derived eccentricity is too small to be of any significance. Based on observations collected at the Calar Alto Observatory, Almería, Spain.

  19. Quarks in Few Body Nuclei

    Science.gov (United States)

    Holt, Roy J.

    2016-03-01

    Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  20. Quarks in Few Body Nuclei

    Directory of Open Access Journals (Sweden)

    Holt Roy J.

    2016-01-01

    Full Text Available Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

  1. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years...

  2. Nuclear-matter distributions of halo nuclei from elastic proton scattering in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Egelhof, P.; Bauchet, A.; Fritz, S.; Geissel, H.; Gross, C.; Kraus, G.; Muenzenberg, G.; Neumaier, S.R.; Schaefer, T.; Scheidenberger, C. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Alkhazov, G.D.; Andronenko, M.N.; Gavrilov, G.E.; Khanzadeev, A.V.; Korolev, G.A.; Lobodenko, A.A.; Seliverstov, D.M.; Timofeev, N.A. [Petersburg Nuclear Physics Institute (PNPI), RU-188300 Gatchina (Russian Federation); Dobrovolsky, A.V. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Petersburg Nuclear Physics Institute (PNPI), RU-188300 Gatchina (Russian Federation); Mutterer, M. [Institut fuer Kernphysik (IKP), Technische Universitaet, D-64289 Darmstadt (Germany); Vorobyov, A.A.; Yatsoura, V.I.

    2002-10-01

    Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections for small-angle scattering were measured at energies near 700 MeV/u for the neutron-rich helium isotopes {sup 6}He and {sup 8}He, and more recently for the lithium isotopes {sup 6}Li, {sup 8}Li, {sup 9}Li and {sup 11}Li, using He and Li beams provided by the fragment separator FRS at GSI Darmstadt. Experiments were performed in inverse kinematics using the hydrogen-filled ionization chamber IKAR which served simultaneously as target and recoil-proton detector. For deducing nuclear-matter distributions, differential cross-sections calculated with the aid of the Glauber multiple-scattering theory, using various parametrizations for the nucleon density distributions as input, were fitted to the experimental cross-sections. The results on nuclear-matter radii and matter distributions are presented, and the significance of the data for a halo structure is discussed. Nuclear-matter distributions obtained for {sup 6}He and {sup 8}He conform with the concept that both nuclei compose of {alpha}-particle like cores and significant neutron halos. The matter distribution in {sup 11}Li exhibits, as expected from previous reaction cross-section studies with nuclear targets, the by far most extended halo component of all nuclei being investigated. In addition the present data allow a quantitative comparison of the structure of the He and Li isobars of either the mass number A=6 or A=8. The measured differential cross-sections have also been used for probing density distributions as predicted from various microscopic calculations. A few examples are presented. (orig.)

  3. Zebrafish fgf10b has a complementary function to fgf10a in liver and pancreas development.

    Science.gov (United States)

    Yan, Chuan; Zheng, Weiling; Gong, Zhiyuan

    2015-04-01

    Fgf10 is a critical growth factor in mammals for development of endodermal organs such as the liver, pancreas, lung, and gut. Due to whole genome duplication, the zebrafish has two fgf10 orthologs, fgf10a and fgf10b. While fgf10a has a role in development of the esophagus and swimbladder, we found in the present study that fgf10b had a complementary expression pattern in the liver, pancreas, and gut. Morpholino knockdown of Fgf10b further confirmed its essential role in the normal development of liver and pancreas. Thus, our data provide another example of functional partition of two duplicated othologous genes during evolution.

  4. The cochlear nuclei of snakes.

    Science.gov (United States)

    Miller, M R

    1980-08-15

    The cochlear nuclei of three burrowing snakes (Xenopeltis unicolor, Cylindrophis rufus, and Eryx johni) and three non-burrowing snakes (Epicrates cenchris, Natrix sipedon, and Pituophis catenifer) were studied. The posterior branch of the statoacoustic nerve and its posterior ganglion were destroyed and the degenerated nerve fibers and terminals traced to primary cochlear nuclei in 13 specimens of Pituophis catenifer. All these snake species possess three primary and one secondary cochlear nuclei. The primary cochlear nuclei consist of a small nucleus angularis located at the cerebello-medullary junction and a fairly large nucleus magnocellularis forming a dorsal cap over the cephalic end of the alar eminence. Nucleus magnocellularis may be subdivided into a medially placed group of rounder cells, nucleus magnocellularis medialis, and a laterally placed group of more ovate and paler-staining cells, nucleus magnocellularis lateralis. A small but well-defined secondary nucleus which showed no degenerated nerve terminals after nerve root section, nucleus laminaris, underlies the cephalic part of both nucleus magnocellularis medialis and nucleus magnocellularis lateralis. Larger and better-developed cochlear nuclei were found in burrowing species than in non-burrowing species of snakes. Of the three burrowing species studied, Xenopeltis showed the greatest development of cochlear nuclei; Eryx cochlear nuclei were not quite as large but were better differentiated than in Xenopeltis; and Cylindrophis cochlear nuclei were fairly large but not as well developed nor as well differentiated as in either Xenopeltis or Eryx. The cochlear nuclei of the three non-burrowing snakes, Epicrates, Natrix, and Pituophis, were not as large nor as well developed as those of the burrowing snakes. There is some, but not complete, correlation between cochlear development and papilla basilaris length and number of hair cells. Thus, Xenopeltis and Eryx, with well-developed cochlear nuclei

  5. Isospin Projected Antisymmetrized Molecular Dynamics and its Application to ${}^{10}$B

    CERN Document Server

    Morita, Hiroyuki

    2016-01-01

    To investigate $pn$ pair correlations in $N=Z=\\textrm{odd}$ nuclei, we develop a new framework based on the generator coordinate method of the $\\beta\\gamma$ constraint antisymmetrized molecular dynamics. In the framework, the isospin projection is performed before the energy variation to obtain the wave function optimized for each isospin. We apply the method to ${}^{10} \\textrm{B}$ and show that it works well to describe coexistence of $T=0$ and $T=1$ states in low-energy spectra. Structures of low-lying states and $pn$ correlations are investigated. Strong $M1$($0^+_1\\rightarrow 1^+_1$) and $E2$($1^+_1\\rightarrow 1^+_2$) transitions are understood by the spin excitation of the $pn$ pair and the rotation of a deformed core, respectively.

  6. Comparison of the effects of couplings to breakup channels in reactions induced by {sup 6}Li and {sup 6}He on the same {sup 64}Zn target

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-García, J. P., E-mail: fernandez@lns.infn.it; Di Pietro, A.; Figuera, P.; Fisichella, M. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Scuderi, V.; Torresi, D. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Dipartamento di Fisica e Astronomia, via S. Sofia 64, I-95123 Catania (Italy); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Seville (Spain); Zadro, M. [Ruder Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb (Croatia)

    2015-10-15

    The experimental elastic scattering angular distributions for the weakly bound nuclei {sup 6,7}Li and for the halo nucleus {sup 6}He on the same {sup 64}Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the {sup 6,7}Li+ {sup 64}Zn systems have been analyzed within the CDCC method, while the {sup 6}He+{sup 64}Zn data have been compared with both both CDCC and CRC calculations.

  7. Study of the $\\bm{p+^6}$Li$\\bm{\\to\\eta+^7}$Be reaction 11.3 MeV above threshold

    CERN Document Server

    Budzanowski, A; Hawranek, P; Jahn, R; Jha, V; Kilian, K; Kliczewski, S; Kirillov, Da; Kirillov, Di; Kolev, D; Kravcikova, M; Lesiak, M; Lieb, J; Machner, H; Magiera, A; Maier, R; Martinska, G; Piskunov, N; Protić, D; Ritman, J; von Rossen, P; Roy, B J; Sitnik, I; Siudak, R; Tsenov, R; Urban, J; Vankova, G

    2010-01-01

    The cross section for the reaction $p+^6\\text{Li}\\to\\eta+^7\\text{Be}$ was measured at an excess energy of 11.28 MeV above threshold by detecting the recoiling $^7$Be nuclei. A dedicated set of focal plane detectors was built for the magnetic spectrograph Big Karl and was used for identification and four momentum measurement of the $^7$Be. A differential cross section of $\\frac{d\\sigma}{d\\Omega}=(0.69\\pm{0.20}\\text{(stat.)}\\pm 0.20\\text{(syst.)})\\text{nb/sr}$ for the ground state plus the 1/2$^-$ was measured. The result is compared to model calculations.

  8. Collective excitations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph

    1997-12-31

    The properties of the nucleus cannot be reduced to the properties of its constituents: it is a complex system. The fact that many properties of the nucleus are consequences of the existence of mean-field potential is a manifestation of this complexity. In particular the nucleons can thus self-organize in collective motions such as giant resonances. Therefore the study of these collective motions is a very good to understand the properties of the nucleus itself. The purpose of this article was to stress some aspects of these collective vibrations. In particular we have studied how an ensemble of fermions as the nucleus can self-organize in collective vibrations which are behaving like a gas of bosons in weak interaction. The understanding of these phenomena remains one of the important subjects of actually in the context of quantal systems in strong interaction. In particular the study of the states with one or two vibration quanta provides a direct information on the structure if nuclei close to their ground states. (author) 270 refs.

  9. Gluon density in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)

    1996-10-01

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.

  10. The locus of microRNA-10b: a critical target for breast cancer insurgence and dissemination.

    Science.gov (United States)

    Biagioni, Francesca; Bossel Ben-Moshe, Noa; Fontemaggi, Giulia; Yarden, Yosef; Domany, Eytan; Blandino, Giovanni

    2013-08-01

    Contemporary microRNA research has led to significant advances in our understanding of the process of tumorigenesis. MicroRNAs participate in different events of a cancer cell's life, through their ability to target hundreds of putative transcripts involved in almost every cellular function, including cell cycle, apoptosis, and differentiation. The relevance of these small molecules is even more evident in light of the emerging linkage between their expression and both prognosis and clinical outcome of many types of human cancers. This identifies microRNAs as potential therapeutic modifiers of cancer phenotypes. From this perspective, we overview here the miR-10b locus and its involvement in cancer, focusing on its role in the establishment (miR-10b*) and spreading (miR-10b) of breast cancer. We conclude that targeting the locus of microRNA 10b holds great potential for cancer treatment.

  11. Boron depletion: indirect measurement of the 10B(p,α)7Be S(E)-factor

    Science.gov (United States)

    Lamia, L.; Romano, S.; Carlin, N.; Cherubini, S.; Crucillà, V.; de Moura, M. M.; Del Santo, M. G.; Munhoz, M. G.; Gulino, M.; Liguori Neto, R.; La Cognata, M.; Mudò, F.; Pizzone, R. G.; Puglia, S. M. R.; Sergi, M. L.; Souza, F. A.; Spitaleri, C.; Suaide, A. A. P.; Szanto, E.; Szanto de Toledo, A.; Tudisco, S.; Tumino, A.

    2007-05-01

    The 10B(p,α)7Be reaction is the main responsible for 10B destruction in stellar interior. In such environments this p-capture process occurs at a Gamow energy of ˜10 keV, and takes places mainly through a resonant state (E=8.701 MeV) of the compound 11C nucleus. Thus, a resonance right in the region of the Gamow peak is expected to significantly influence the behaviour of the astrophysical S(E)-factor. The 10B(p,α)7Be reaction has been investigated by means of the Trojan Horse Method (THM) applied to the 2H(10B,α7Be)n three-body process. The experiment was performed at E=27 MeV at the Instituto de Fisica Nuclear de São Paulo. Preliminary results concerning the extraction of the bare-nucleus S(E)-factor will be presented.

  12. Monopole transitions in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sujkowski, Z. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

    1994-12-31

    Monopole transitions can be a signature of shape changing in a hot, pulsating nucleus (the low energy E0 mode) and/or a measure of the compressibility of finite nuclei (GMR, the breathing mode). Experimental information pertaining to GMR is reviewed. Recipes for deducing the incompressibility modules for infinite nuclear matter from data on GMR are discussed. Astrophysical implications are outlined. The first attempts at locating the GMR strength in moderately hot nuclei are described. Prospects for improving the experimental techniques to make an observation of this strength in selected nuclei unambiguous are discussed. (author). 46 refs, 8 figs.

  13. Spectroscopy of heavy fissionable nuclei

    Indian Academy of Sciences (India)

    S K Tandel

    2015-09-01

    Structural studies of heavy nuclei are quite challenging due to increased competition from fission, particularly at high spins. Nuclei in the actinide region exhibit a variety of interesting phenomena. Recent advances in instrumentation and analysis techniques have made feasible sensitive measurements of nuclei populated with quite low cross-sections. These include isomers and rotational band structures in isotopes of Pu ( = 94) to Rf ( = 104), and octupole correlations in the Th ( = 90) region. The obtained experimental data have provided insights on various aspects like moments of inertia and nucleon alignments at high spins, quasiparticle energies and evolution of quadrupole and octupole collectivity, among others. An overview of some of these results is presented.

  14. Theoretical Analysis of Neutron Double-differental Cross Section of n+10B at 14.2 MeV

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Having very large neutron absorption cross-section at low energies, 10B has long been selected as theshielding material in nuclear engineering. In the reactions of n+10B there are many partial reactionchannels to be opened even at incident neutron energies of 14 MeV Since the new approach fordescription of neutron induced light nucleus reaction was proposed in 1999, many experimental data,

  15. Effects of MicroRNA-10b on lung cancer cell proliferation and invasive metastasis and the underlying mechanism

    Institute of Scientific and Technical Information of China (English)

    Qiao-Li Su; Shuang-Qing Li; Duo-Ning Wang; Feng Liu; Bo Yuan

    2014-01-01

    Objective:To study the influence ofMicroRNA-10b on proliferation and invasion of human low metastatic lung cancer cell95-C and its mechanism.Methods:LipofectamineMicroRNA-10b eukaryotic expression plasmid was transfected into95-C.The experiment group was divided into blank control group, empty vector transfected group andMicroRNA-10b transfected group.Real time quantitativeRT-PCR was used to detect theexpression ofMicroRNA-10b and KLF4mRNA expression.Proliferations of cells were detected by cell proliferation assay, invasion of the detected the cellTranswell experiments, the expression ofKLF4 protein was detected in Western blotting cells.Results:The proliferation rate ofMicroRNA-10b plasmid transfection group increased significantly after transfection, invasion and migration ability enhancement, by comparison, there are statistically significant differences in the blank control group and negative control group(P0.05). Conclusions:MicroRNA-10b may promote proliferation and invasion of95-C cells by down regulating the expression ofKLF4 protein.

  16. Extra tyrosine in the carbohydrate-binding module of Irpex lacteus Xyn10B enhances its cellulose-binding ability.

    Science.gov (United States)

    Nishijima, Hiroto; Nozaki, Kouichi; Mizuno, Masahiro; Arai, Tsutomu; Amano, Yoshihiko

    2015-01-01

    The xylanase (Xyn10B) that strongly adsorbs on microcrystalline cellulose was isolated from Driselase. The Xyn10B contains a Carbohydrate-binding module family 1 (CBM1) (IrpCBMXyn10B) at N-terminus. The canonical essential aromatic residues required for cellulose binding were conserved in IrpCBMXyn10B; however, its adsorption ability was markedly higher than that typically observed for the CBM1 of an endoglucanase from Trametes hirsuta (ThCBMEG1). An analysis of the CBM-GFP fusion proteins revealed that the binding capacity to cellulose (7.8 μmol/g) and distribution coefficient (2.0 L/μmol) of IrpCBMXyn10B-GFP were twofold higher than those of ThCBMEG1-GFP (3.4 μmol/g and 1.2 L/μmol, respectively), used as a reference structure. Besides the canonical aromatic residues (W24-Y50-Y51) of typical CBM1-containing proteins, IrpCBMXyn10B had an additional aromatic residue (Y52). The mutation of Y52 to Ser (IrpCBMY52S-GFP) reduced these adsorption parameters to 4.4 μmol/g and 1.5 L/μmol, which were similar to those of ThCBMEG1-GFP. These results indicate that Y52 plays a crucial role in strong cellulose binding.

  17. Development of 10B-Based 3He Replacement Neutron Detectors

    Science.gov (United States)

    King, Michael J.; Gozani, Tsahi; Hilliard, Donald B.

    2011-12-01

    Radiation portal monitors (RPM) are currently deployed at United States border crossings to passively inspect vehicles and persons for any emission of neutrons and/or gamma rays, which may indicate the presence of unshielded nuclear materials. The RPM module contains an organic scintillator with 3He proportional counters to detect gamma rays and thermalized neutrons, respectively. The supply of 3He is rapidly dwindling, requiring alternative detectors to provide the same function and performance. Our alternative approach is one consisting of a thinly-coated 10B flat-panel ionization chamber neutron detector that can be deployed as a direct drop-in replacement for current RPM 3He detectors. The uniqueness of our approach in providing a large-area detector is in the simplicity of construction, scalability of the unit cell detector, ease of adaptability to a variety of applications and low cost. Currently, Rapiscan Laboratories and Helicon Thin Film Systems have designed and developed an operational 100 cm2 multi-layer prototype 10BB-based ionization chamber.

  18. Tidal dissipation in a homogeneous spherical body. II. Three examples: Io, Mercury, and Kepler-10 b

    CERN Document Server

    Makarov, Valeri V

    2014-01-01

    In Efroimsky & Makarov (2014), we derived from the first principles a formula for the tidal heating rate in a tidally perturbed homogeneous sphere. We compared it with the formulae used in the literature, and pointed out the differences. Using this result, we now present three case studies - Mercury, Kepler-10b, and a triaxial Io. A very sharp frequency-dependence of k2/Q near spin-orbit resonances yields a similarly sharp dependence of k2/Q on the spin rate. This indicates that physical libration may play a major role in tidal heating of synchronously rotating bodies. The magnitude of libration in the spin rate being defined by the planet's triaxiality, the latter should be a factor determining the dissipation rate. Other parameters equal, a synchronously rotating body with a stronger triaxiality should generate more heat than a similar body of a more symmetrical shape. Further in the paper, we discuss scenarios where initially triaxial objects melt and lose their triaxiality. Thereafter, dissipation in ...

  19. Novel concept for neutron detection: proportional counter filled with 10B nanoparticle aerosol

    Science.gov (United States)

    Amaro, F. D.; Monteiro, C. M. B.; dos Santos, J. M. F.; Antognini, A.

    2017-01-01

    The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters. PMID:28181520

  20. Preparation and Characterization of High Purity Enriched10B Boric Acid via Anti-Solvent Recrystallization

    Institute of Scientific and Technical Information of China (English)

    张卫江; 刘天雨; 徐姣

    2016-01-01

    Self-made enriched10B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5,℃and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.

  1. Novel concept for neutron detection: proportional counter filled with 10B nanoparticle aerosol

    Science.gov (United States)

    Amaro, F. D.; Monteiro, C. M. B.; Dos Santos, J. M. F.; Antognini, A.

    2017-02-01

    The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters.

  2. Pseudospin Dynamical Symetry in Nuclei

    CERN Document Server

    Ginocchio, Joseph N

    2014-01-01

    Pseudospin symmetry has been useful in understanding atomic nuclei. We review the arguments that this symmetry is a relativistic symmetry. The condition for this symmetry is that the sum of the vector and scalar potentials in the Dirac Hamiltonian is a constant. We give the generators of pseudospin symmetry. We review some of the predictions that follow from this insight into the relativistic origins of pseudospin symmetry. Since in nuclei the sum of the scalar and vector potentials is not zero but is small, we discuss preliminary investigations into the conditions on the potentials to produce partial dynamic pseudospin symmetry. Finally we show that approximate pseudospin symmetry in nuclei predicts approximate spin symmetry in anti-nucleon scattering from nuclei.

  3. Physics with loosely bound nuclei

    Indian Academy of Sciences (India)

    Chhanda Samanta

    2001-08-01

    The essential aspect of contemporary physics is to understand properties of nucleonic matter that constitutes the world around us. Over the years research in nuclear physics has provided strong guidance in understanding the basic principles of nuclear interactions. But, the scenario of nuclear physics changed drastically as the new generation of accelerators started providing more and more rare isotopes, which are away from the line of stability. These weakly bound nuclei are found to exhibit new forms of nuclear matter and unprecedented exotic behaviour. The low breakup thresholds of these rare nuclei are posing new challenges to both theory and experiments. Fortunately, nature has provided a few loosely bound stable nuclei that have been studied thoroughly for decades. Attempts are being made to find a consistent picture for the unstable nuclei starting from their stable counterparts. Some significant differences in the structure and reaction mechanisms are found.

  4. Nanocrystallization kinetics and glass forming ability of the Fe65Nb10B25 metallic alloy

    Science.gov (United States)

    Torrens-Serra, J.; Rodríguez-Viejo, J.; Clavaguera-Mora, M. T.

    2007-12-01

    The crystallization kinetics of glassy Fe65Nb10B25 melt-spun ribbons is studied by differential scanning calorimetry in the mode of continuous heating and isothermal annealing and by x-ray diffraction and transmission electron microscopy. Continuous heat treatments of the ribbons show the presence of multiple exothermic peaks before melting. The low-temperature peak corresponds to the precipitation of nanoscale Fe23B6 -type crystalline metastable phase, and further annealing leads to its transformation into the metastable Fe3B phase and subsequent formation of bcc-Fe , Fe2B , and FeNbB stable crystalline phases. The nucleation frequency and the growth rate are determined at selected temperatures from the analysis of the microstructures that emerge during the Fe23B6 -type nanocrystallization. The master curve method is used to obtain the apparent activation energy and the Avrami exponent at the nanocrystallization onset. The nanocrystallization kinetics is explained in the framework of the Kolmogorov-Johnson-Mehl-Avrami theory. The rejection of insoluble alloy atoms during primary crystallization, the formation of diffusion layers around the crystals, and the decrease in the nucleation frequency caused by alloy enrichment of the residual disordered matrix is modeled through a soft impingement factor. Estimated values for the interfacial energy that provide a satisfactory agreement between experiments and modeling are derived considering that homogeneous nucleation frequency and interface-controlled grain growth are dominant at the onset of the nanocrystallization. Consequently, the time-temperature-transformation diagram is also drawn and the critical cooling rate estimated for this glass forming alloy.

  5. Reprocessing of {sup 10}B-contaminated {sup 10}Be AMS targets

    Energy Technology Data Exchange (ETDEWEB)

    Simon, K.J., E-mail: ksz@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee NSW 2232 (Australia); Pedro, J.B. [Institute of Marine and Antarctic Studies, Private Bag 129, Hobart TAS 7001 (Australia); Antarctic Climate and Ecosystems Cooperative Research Centre, Private Bag 80, Hobart TAS 7001 (Australia); Smith, A.M.; Child, D.P.; Fink, D. [Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee NSW 2232 (Australia)

    2013-01-15

    {sup 10}Be accelerator mass spectrometry (AMS) is an increasingly important tool in studies ranging from exposure age dating and palaeo-geomagnetism to the impact of solar variability on the Earth's climate. High levels of boron in BeO AMS targets can adversely impact the quality of {sup 10}Be measurements through interference from the isobar {sup 10}B. Numerous methods in chemical sample preparation and AMS measurement have been employed in order to reduce the impact of excessive boron rates. We present details of a method developed to chemically reprocess a set of forty boron-contaminated BeO targets derived from modern Antarctic ice. Previously, the excessive boron levels in these samples, as measured in an argon-filled absorber cell preceding the ionisation detector, had precluded routine AMS measurement. The procedure involved removing the BeO + Nb mixture from the target holders and dissolving the BeO in hot concentrated H{sub 2}SO{sub 4}. The solution was then heated with HF to remove the boron as volatile BF{sub 3} before re-precipitating as Be(OH){sub 2} and calcining to BeO. This was again mixed with niobium and pressed into fresh target holders. Following reprocessing, the samples gave boron rates reduced by 10-100 Multiplication-Sign , which were sufficiently low and similar to previous successful batches of ice core, snow and associated blank samples, thus allowing a successful {sup 10}Be measurement in the absence of any boron correction. Overall recovery of the BeO for this process averaged 40%. Extensive testing of relevant processing equipment and reagents failed to determine the source of the boron. As a precautionary measure, a similar H{sub 2}SO{sub 4} + HF step has been subsequently added to the standard ice processing method.

  6. EFECTO DE FACTORES EXTRINSECOS SOBRE LA ACTIVIDAD ANTIMICROBIANA DEL METABOLITO W10b PRODUCIDO POR Weissella confusa

    Directory of Open Access Journals (Sweden)

    LILIANA SERNA-COCK

    2014-06-01

    Full Text Available Las bacterias ácido lácticas producen sustancias antimicrobianas que pueden perder su actividad debido a factores extrínsecos. En este estudio se determinaron los efectos de temperatura, pH, tiempo de exposición y enzimas sobre la actividad antimicrobiana del metabolito W10b producido por la bacteria ácido láctica Weissella confusa. W10b es activo contra Staphylococcus aureus y Streptococcus agalactiae. W. confusa se produjo mediante fermentación a 32°C por 4 horas y el metabolito W10b se obtuvo a partir del sobrenadante libre de células mediante centrifugación, filtración y liofilización. W10b se sometió a pH ácido, neutro y básico, para dos tiempos de exposición (10 y 30 minutos y diferentes temperaturas (27, 40, 60 y 100°C. Además se midió el efecto de las enzimas pepsina y amiloglucosidasa sobre W10b. Se encontró diferencias significativas (p<0,05 de la actividad antimicrobiana de W10b por efectos de pH y temperaturas, donde la mayor actividad antimicrobiana se obtuvo, contra S. aureus en medio básico a 27°C y contra S. agalactiae en medio neutro a 27°C. W10b presentó sensibilidad frente a las enzimas pepsina y amiloglucosidasa, indicando la naturaleza proteica y complejidad química del metabolito. Estos resultados orientan el uso industrial o comercial del compuesto antimicrobiano y señala el camino de futuras investigaciones.

  7. Assessment of (10)B concentration in boron neutron capture therapy: potential of image-guided therapy using (18)FBPA PET.

    Science.gov (United States)

    Shimosegawa, Eku; Isohashi, Kayako; Naka, Sadahiro; Horitsugi, Genki; Hatazawa, Jun

    2016-12-01

    In boron neutron capture therapy (BNCT) for cancer, the accurate estimation of (10)B tissue concentrations, especially in neighboring normal organs, is important to avoid adverse effects. The (10)B concentration in normal organs after loading with (10)B, however, has not been established in humans. In this study, we performed 4-borono-2-[(18)F]-fluoro-phenylalanine ((18)FBPA) PET in healthy volunteers and estimated the chronological changes in the (10)B concentrations of normal organs. In 6 healthy volunteers, whole-body (18)FBPA PET scans were repeated 7 times during 1 h, and the mean (18)FBPA distributions of 13 organs were measured. Based on the (18)FBPA PET data, we then estimated the changes in the (10)B concentrations of the organs when the injection of a therapeutic dose of (10)BPA-fructose complex ((10)BPA-fr; 30 g, 500 mg/kg body weight) was assumed. The maximum mean (18)FBPA concentrations were reached at 2-6 min after injection in all the organs except the brain and urinary bladder. The mean (18)FBPA concentration in normal brain plateaued at 24 min after injection. When the injection of a therapeutic dose of (10)BPA-fr was assumed, the estimated mean (10)B concentration in the kidney increased to 126.1 ± 24.2 ppm at 3 min after injection and then rapidly decreased to 30.9 ± 7.4 ppm at 53 min. The estimated mean (10)B concentration in the bladder gradually increased and reached 383.6 ± 214.7 ppm at 51 min. The mean (10)B concentration in the brain was estimated to be 7.6 ± 1.5 ppm at 57 min. (18)FBPA PET has a potential to estimate (10)B concentration of normal organs before neutron irradiation of BNCT when several assumptions are validated in the future studies.

  8. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra.

    Science.gov (United States)

    Marashdeh, Ali; Frankcombe, Terry J

    2008-06-21

    The dehydrogenation enthalpies of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski's direct method. The dehydrogenation of Ca(AlH(4))(2) is exothermic, indicating a metastable hydride. Calculations for CaAlH(5) including ZPE effects indicate that it is not stable enough for a hydrogen storage system operating near ambient conditions. The destabilized combination of LiBH(4) with CaH(2) is a promising system after ZPE-corrected enthalpy calculations. The calculations confirm that including ZPE effects in the harmonic approximation for the dehydrogenation of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) has a significant effect on the calculated reaction enthalpy. The contribution of ZPE to the dehydrogenation enthalpies of Ca(AlH(4))(2) and CaAlH(5) calculated by the direct method phonon analysis was compared to that calculated by the frozen-phonon method. The crystal structure of CaAlH(5) is presented in the more useful standard setting of P2(1)c symmetry and the phonon density of states of CaAlH(5), significantly different to other common complex metal hydrides, is rationalized.

  9. The use of enriched 6Li and 7Li Lif:Mg,Cu,P glass-rod thermoluminescent dosemeters for linear accelerator out-of-field radiation dose measurements.

    Science.gov (United States)

    Takam, R; Bezak, E; Liu, G; Marcu, L

    2012-06-01

    (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescent dosemeters (TLDs) were used for measurements of out-of-field photon and neutron doses produced by Varian iX linear accelerator. Both TLDs were calibrated using 18-MV X-ray beam to investigate their dose-response sensitivity and linearity. CR-39 etch-track detectors (Luxel+, Landauer) were employed to provide neutron dose data to calibrate (6)LiF:Mg,Cu,P TLDs at various distances from the isocentre. With cadmium filters employed, slow neutrons (neutrons. The average in-air photon dose equivalents per monitor unit (MU) ranged from 1.5±0.4 to 215.5±94.6 μSv at 100 and 15 cm from the isocentre, respectively. Based on the cross-calibration factors obtained with CR-39 etch-track detectors, the average in-air fast neutron dose equivalents per MU range from 10.6±3.8 to 59.1±49.9 μSv at 100 and 15 cm from the isocentre, respectively. Contribution of thermal neutrons to total neutron dose equivalent was small: 3.1±7.2 μSv per MU at 15 cm from the isocentre.

  10. 基于6LiF/ZnS(Ag)闪烁体波移光纤读出中子探测器模拟研究%The Monte-Carlo Simulation on Neutron Detector of 6LiF/ZnS(Ag)Scintillator Using Wavelength-Shifting Readout Fibers

    Institute of Scientific and Technical Information of China (English)

    吴冲; 张强; 张鹏; 孙志嘉; 唐彬; 王拓

    2012-01-01

    利用GEANT4构建二维位置灵敏型闪烁体中子探测器模型,并对探测器的关键性能进行了系统的模拟研究.计算结果表明,采用双层闪烁屏与波移光纤作为夹层的“三明治”式结构探测器,其热中子探测效率可以达到49.1%.模拟和实验均表明:探测器具有较好的n/γ抑制能力.γ灵敏度小于10-5;中子位置分辨率随着光纤芯间距和光纤与闪烁屏距离的减小呈现减小趋势,本征空间分辨率最好可以达到X轴0.08 mm,Y轴0.12 mm;光纤与闪烁屏之间采用空气耦合位置分辨率好于硅油耦合.模拟结果与部分实验结果的对比验证显示,探测器具有较好的二维成像能力.%A prototype of position sensitive neutron detector based on 6LiF/ZnS(Ag) scintillator was constructed by GEANT 4 package, and its key properties were studied. The simulation result shows that the thermal neutron detection efficiency could reach 49.1% when the "sandwich structure" of detector was set. Both simulation and experimental result plot its good ability of n/y rejection ration,and the gamma sensitive is less than 10-5. The influences of the coupled material and space between wavelength shift fibers and scintillator,as well as the space between two fibers are considered. The intrinsic spatial resolution is 0. 08 mm for X-axis and 0.12 mm for Y-axis,and the detector has a good 2D imaging capability. The simulation results are compared with that of parts experimental results.

  11. From heavy nuclei to super-heavy nuclei

    CERN Document Server

    Theisen, C

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei.

  12. Porous chitosan doped with graphene oxide as highly effective adsorbent for methyl orange and amido black 10B.

    Science.gov (United States)

    Wang, Ying; Xia, Guangmei; Wu, Cong; Sun, Jing; Song, Rui; Huang, Wei

    2015-01-22

    In the current study, porous chitosan aerogels doped with small amount of graphene oxide (CSGO aerogels) with high porosity (97.96-98.78%), extraordinarily high water absorption (5848-8917%) and low density (0.021-0.035 g cm(-3)) were prepared and used as adsorbents for two azo dyes methyl orange (MO) and amido black 10B (AB10B). The adsorption behavior of these CSGO aerogels and some influence factors such as pH value, graphene oxide (GO) loading, concentration of pollutants, as well as adsorption kinetics were studied. Specifically, the adsorption capacity for MO is 686.89 mg g(-1), the highest comparing with other publication results, and it is 573.47 mg g(-1) for AB10B. Since they are biodegradable, non-toxic, efficient, low-cost and easy to prepare, we believe that these porous CSGO aerogels will be a promising candidate for dye removal.

  13. Reduction of TIP30 in esophageal squamous cell carcinoma cells involves promoter methylation and microRNA-10b

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Wenjie, E-mail: dongwenjie200581@126.com [Department of Internal Medicine-Oncology, The First Affiliated Hospital, Zhengzhou University (China); Shen, Ruizhe; Cheng, Shidan [Department of Gastroenterology, Rui-jin Hospital, Shanghai Jiao Tong University, Shanghai (China)

    2014-10-31

    Highlights: • TIP30 expression is frequently suppressed in ESCC. • TIP30 was hypermethylated in ESCC. • Reduction of TIP30 was significantly correlated with LN metastasis. • miR-10b is a direct regulator of TIP30. - Abstract: TIP30 is a putative tumor suppressor that can promote apoptosis and inhibit angiogenesis. However, the role of TIP30 in esophageal squamous cell carcinoma (ESCC) biology has not been investigated. Immunohistochemistry was used to investigate the expression of TIP30 in 70 ESCC. Hypermethylation of TIP30 was evaluated by the methylation specific PCR (MSP) method in ESCC (tumor and paired adjacent non-tumor tissues). Lost expression of TIP30 was observed in 50 of 70 (71.4%) ESCC. 61.4% (43 of 70) of primary tumors analyzed displayed TIP30 hypermethylation, indicating that this aberrant characteristic is common in ESCC. Moreover, a statistically significant inverse association was found between TIP30 methylation status and expression of the TIP30 protein in tumor tissues (p = 0.001). We also found that microRNA-10b (miR-10b) targets a homologous DNA region in the 3′untranslated region of the TIP30 gene and represses its expression at the transcriptional level. Reporter assay with 3′UTR of TIP30 cloned downstream of the luciferase gene showed reduced luciferase activity in the presence of miR-10b, providing strong evidence that miR-10b is a direct regulator of TIP30. These results suggest that TIP30 expression is regulated by promoter methylation and miR-10b in ESCC.

  14. Structural insights into the specificity of Xyn10B from Paenibacillus barcinonensis and its improved stability by forced protein evolution.

    Science.gov (United States)

    Gallardo, Oscar; Pastor, F I Javier; Polaina, Julio; Diaz, Pilar; Łysek, Robert; Vogel, Pierre; Isorna, Pablo; González, Beatriz; Sanz-Aparicio, Julia

    2010-01-22

    Paenibacillus barcinonensis is a soil bacterium bearing a complex set of enzymes for xylan degradation, including several secreted enzymes and Xyn10B, one of the few intracellular xylanases reported to date. The crystal structure of Xyn10B has been determined by x-ray analysis. The enzyme folds into the typical (beta/alpha)(8) barrel of family 10 glycosyl hydrolases (GH10), with additional secondary structure elements within the beta/alpha motifs. One of these loops -L7- located at the beta7 C terminus, was essential for xylanase activity as its partial deletion yielded an inactive enzyme. The loop contains residues His(249)-Glu(250), which shape a pocket opened to solvent in close proximity to the +2 subsite, which has not been described in other GH10 enzymes. This wide cavity at the +2 subsite, where methyl-2,4-pentanediol from the crystallization medium was found, is a noteworthy feature of Xyn10B, as compared with the narrow crevice described for other GH10 xylanases. Docking analysis showed that this open cavity can accommodate glucuronic acid decorations of xylo-oligosaccharides. Co-crystallization experiments with conduramine derivative inhibitors supported the importance of this open cavity at the +2 subsite for Xyn10B activity. Several mutant derivatives of Xyn10B with improved thermal stability were obtained by forced evolution. Among them, mutant xylanases S15L and M93V showed increased half-life, whereas the double mutant S15L/M93V exhibited a further increase in stability, showing a 20-fold higher heat resistance than the wild type xylanase. All the mutations obtained were located on the surface of Xyn10B. Replacement of a Ser by a Leu residue in mutant xylanase S15L can increase hydrophobic packing efficiency and fill a superficial indentation of the protein, giving rise to a more compact structure of the enzyme.

  15. Reference systems for the determination of {sup 10}B through autoradiography images: Application to a melanoma experimental model

    Energy Technology Data Exchange (ETDEWEB)

    Portu, A., E-mail: portu@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, AC: C1033AAJ, Ciudad Autonoma de Buenos Aires (Argentina); Carpano, M., E-mail: carpano@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina); Dagrosa, A., E-mail: dagrosa@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)] [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, AC: C1033AAJ, Ciudad Autonoma de Buenos Aires (Argentina); Nievas, S., E-mail: nievas@cnea.gov.ar [Centro Atomico Constituyentes (CAC), Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, AC: B1650KNA, San Martin, Buenos Aires (Argentina)

    2011-12-15

    The amount of {sup 10}B in tissue samples may be determined by measuring the track density in the autoradiography image produced on a nuclear track detector. Different systems were evaluated as reference standards to be used for a quantitative evaluation of boron concentration. The obtained calibration curves were applied to evaluate the concentration of {sup 10}B in melanoma tumour of NIH nude mice after a biodistribution study. The histological features observed in the tissue sections were accurately reproduced by the autoradiography images.

  16. Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01

    Science.gov (United States)

    Aguilar, M.; Alcaraz, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Azzarello, P.; Basile, M.; Barao, F.; Barreira, G.; Bartoloni, A.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Béné, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bindi, V.; Boella, G.; Boschini, M.; Bourquin, M.; Bruni, G.; Buénerd, M.; Burger, J. D.; Burger, W. J.; Cai, X. D.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cernuda, I.; Chang, Y. H.; Chen, H. F.; Chen, H. S.; Chen, Z. G.; Chernoplekov, N. A.; Chiueh, T. H.; Choi, Y. Y.; Cindolo, F.; Commichau, V.; Contin, A.; Cortina-Gil, E.; Crespo, D.; Cristinziani, M.; Dai, T. S.; dela Guia, C.; Delgado, C.; Di Falco, S.; Djambazov, L.; D'Antone, I.; Dong, Z. R.; Duranti, M.; Engelberg, J.; Eppling, F. J.; Eronen, T.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P. H.; Flügge, G.; Fouque, N.; Galaktionov, Y.; Gervasi, M.; Giovacchini, F.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W. Q.; Haino, S.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Hungerford, W.; Ionica, M.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kim, D. H.; Kim, G. N.; Kim, K. S.; Kirn, T.; Klimentov, A.; Kossakowski, R.; Kounine, A.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lechanoine-Leluc, C.; Lee, M. W.; Lee, S. C.; Levi, G.; Lin, C. H.; Liu, H. T.; Lu, G.; Lu, Y. S.; Lübelsmeyer, K.; Luckey, D.; Lustermann, W.; Maña, C.; Margotti, A.; Mayet, F.; McNeil, R. R.; Menichelli, M.; Mihul, A.; Mujunen, A.; Oliva, A.; Palmonari, F.; Park, H. B.; Park, W. H.; Pauluzzi, M.; Pauss, F.; Pereira, R.; Perrin, E.; Pevsner, A.; Pilo, F.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Pohl, M.; Produit, N.; Quadrani, L.; Rancoita, P. G.; Rapin, D.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J. P.; Riihonen, E.; Ritakari, J.; Ro, S.; Roeser, U.; Sagdeev, R.; Santos, D.; Sartorelli, G.; Sbarra, C.; Schael, S.; Schultz von Dratzig, A.; Schwering, G.; Seo, E. S.; Shin, J. W.; Shoumilov, E.; Shoutko, V.; Siedenburg, T.; Siedling, R.; Son, D.; Song, T.; Spada, F. R.; Spinella, F.; Steuer, M.; Sun, G. S.; Suter, H.; Tang, X. W.; Ting, Samuel C. C.; Ting, S. M.; Tomassetti, N.; Tornikoski, M.; Torsti, J.; Trümper, J.; Ulbricht, J.; Urpo, S.; Valtonen, E.; Vandenhirtz, J.; Velikhov, E.; Verlaat, B.; Vetlitsky, I.; Vezzu, F.; Vialle, J. P.; Viertel, G.; Vité, D.; Von Gunten, H.; Waldmeier Wicki, S.; Wallraff, W.; Wang, J. Z.; Wiik, K.; Williams, C.; Wu, S. X.; Xia, P. C.; Xu, S.; Xu, Z. Z.; Yan, J. L.; Yan, L. G.; Yang, C. G.; Yang, J.; Yang, M.; Ye, S. W.; Zhang, H. Y.; Zhang, Z. P.; Zhao, D. X.; Zhou, F.; Zhou, Y.; Zhu, G. Y.; Zhu, W. Z.; Zhuang, H. L.; Zichichi, A.; Zimmermann, B.; Zuccon, P.

    2010-11-01

    Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon-1. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.

  17. Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays. Results from AMS-01

    CERN Document Server

    Aguilar, M; Allaby, J; Alpat, B; Ambrosi, G; Anderhub, H; Ao, L; Arefiev, A; Arruda, L; Azzarello, P; Basile, M; Barao, F; Barreira, G; Vartoloni, A; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bindi, V; Boella, G; Boschini, M; Bourquin, M; Bruni, G; Buenerd, M; Burger, J D; Burger, W J; Cai, X D; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cernuda, I; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Chiueh, T H; Choi, Y Y; Cindolo, F; Commichau, V; Contin, A; Cortina-Gil, E; Crespo, D; Cristinziani, M; Dai, T S; Dela Guia, C; Delgado, C; Di Falco, S; Djambazov, L; D'Antoine, I; Dong, Z R; Duranti, M; Engelberg, J; Eppling, F J; Eronen, T; Extermann, P; Favier, J; Fiandrini, E; Fisher, P H; Flugge, G; Fouque, N; Galaktionov, Y; Gervasi, M; Giovacchini, F; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Haino, S; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Hungerford, W; Ionica, M; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kim, D H; Kim, G N; Kim, K S; Kirn, T; Klimentov, A; Kossakowski, R; Kounine, A; Koutsenko, V; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lechanoine-Leluc, C; Lee, M W; Lee, S C; Levi, G; Lin, C H; Liu, H T; Lu, G; Lubelsmeyer, K; Luckey, D; Lustermann, W; Mana, C; Margotti, A; Mayet, F; McNeil, R R; Menichelli, M; Mihul, A; Mujunen, A; Oliva, A; Palmonari, F; Park, H B; Park, W H; Pauluzzi, M; Pauss, F; Pereira, R; Perrin, E; Pevsner, A; Pilo, F; Pimenta, M; Plyaskin, V; Pojidaev, V; Pohl, M; Produit, N; Quadrani, L; Rancoita, P G; Rapin, D; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Ro, S; Roeser, U; Sagdeev, R; Santos, D; Sartorelli, G; Sbarra, C; Schael, S; Schultz von Dratzig, A; Schwering, G; Seo, E S; Shin, J W; Shoumilov, E; Shoutko, V; Siedenburg, T; Siedling, R; Son, D; Song, T; Spada, F R; Spinella, F; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tomassetti, N; Tornikoski, M; Torsti, J; Trumper, J; Ulbricht, J; Urpo, S; Valtonen, E; Vandenhirtz, J; Velikhov, E; Verlaat, B; Vetlitsky, I; Vezzu, F; Vialle, J P; Viertel, G; Vite, D; Von Gunten, H; Waldmeier Wicki, S; Wallraff, W; Wang, J Z; Wiik, K; Williams, C; Wu, S X; Xia, P C; Xu, S; Xu, Z Z; Yan, J L; Yan, L G; Yang, C G; Yang, J; Yang, M; Ye, S W; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhou, F; Zhou, Y; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P

    2010-01-01

    Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper the relative abundances of the light nuclei lithium, beryllium, boron and carbon are presented. The secondary to primary ratios Li/C, Be/C and B/C have been measured in the kinetic energy range 0.35-45 GeV/nucleon. The isotopic ratio 7Li/6Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary to secondary ratios Li/Be, Li/B and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model....

  18. Photodissociation of neutron deficient nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sonnabend, K.; Babilon, M.; Hasper, J.; Mueller, S.; Zarza, M.; Zilges, A. [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)

    2006-03-15

    The knowledge of the cross sections for photodissociation reactions like e.g. ({gamma}, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained. (orig.)

  19. Studies of exotic light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Cerny, J.

    1976-05-01

    For neutron-deficient nuclei, extension of the T/sub z/ = --3/2 series of strong beta-delayed proton precursors to /sup 61/Ge is discussed. For neutron-excess nuclei, heavy-ion induced, multi-nucleon transfer reaction studies of masses and energy levels of 2sld shell nuclei with T/sub z/ greater than or equal to 5/2 are covered. In addition, preliminary attempts to employ the (/sup 7/Li,/sup 2/He) reaction for the latter studies are shown; a new detection system capable of observing unbound final states as reaction products is demonstrated via investigations of the (..cap alpha..,/sup 2/He) reaction.

  20. A relativistic symmetry in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ginocchio, J N [MS B283, Theoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545 (Mexico)

    2007-11-15

    We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We review the case that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry in nuclei. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment. We also discuss the future and what role pseudospin symmetry may be expected to play in an effective field theory of nucleons.

  1. Photoproduction of mesons off nuclei

    CERN Document Server

    Krusche, B

    2011-01-01

    Recent results for the photoproduction of mesons off nuclei are reviewed. These experiments have been performed for two major lines of research related to the properties of the strong interaction. The investigation of nucleon resonances requires light nuclei as targets for the extraction of the isospin composition of the electromagnetic excitations. This is done with quasi-free meson photoproduction off the bound neutron and supplemented with the measurement of coherent photoproduction reactions, serving as spin and/or isospin filters. Furthermore, photoproduction from light and heavy nuclei is a very efficient tool for the study of the interactions of mesons with nuclear matter and the in-medium properties of hadrons. Experiments are currently rapidly developing due to the combination of high quality tagged (and polarized) photon beams with state-of-the-art 4pi detectors and polarized targets.

  2. Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Camila Ramos; Meza, Andreia Navarro [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Hoffmam, Zaira Bruna; Silva, Junio Cota; Alvarez, Thabata Maria; Ruller, Roberto [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Giesel, Guilherme Menegon; Verli, Hugo [Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Squina, Fabio Marcio [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Prade, Rolf Alexander [Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK (United States); Murakami, Mario Tyago, E-mail: mario.murakami@lnbio.org.br [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil)

    2010-12-10

    Research highlights: {yields} The hyperthermostable xylanase 10B from Thermotoga petrophila RKU-1 produces exclusively xylobiose at the optimum temperature. {yields} Circular dichroism spectroscopy suggests a coupling effect of temperature-induced structural changes with its enzymatic behavior. {yields} Crystallographic and molecular dynamics studies indicate that conformational changes in the product release area modulate the enzyme action mode. -- Abstract: Endo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the -1 and -2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20 {sup o}C, and exclusively xylobiose at 90 {sup o}C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures.

  3. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    R A Gherghescu; D N Poenaru

    2015-09-01

    The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the decay of 282,292120 nuclei.

  4. Octupole shapes in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  5. International Symposium on Exotic Nuclei

    CERN Document Server

    Sobolev, Yu G; EXON-2014

    2015-01-01

    The production and the properties of nuclei in extreme conditions, such as high isospin, temperature, angular momenta, large deformations etc., have become the subject of detailed investigations in all scientific centers. The main topics discussed at the Symposium were: Synthesis and Properties of Exotic Nuclei; Superheavy Elements; Rare Processes, Nuclear Reactions, Fission and Decays; Experimental Facilities and Scientific Projects. This book provides a comprehensive overview of the newest results of the investigations in the main scientific centers such as GSI (Darmstadt, Germany), GANIL (Caen, France), RIKEN (Wako-shi, Japan), MSU (Michigan, USA), and JINR (Dubna, Russia).

  6. PDFs from nucleons to nuclei

    CERN Document Server

    Accardi, Alberto

    2016-01-01

    I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.

  7. miR-10b*, a master inhibitor of the cell cycle, is down-regulated in human breast tumours.

    Science.gov (United States)

    Biagioni, Francesca; Bossel Ben-Moshe, Noa; Fontemaggi, Giulia; Canu, Valeria; Mori, Federica; Antoniani, Barbara; Di Benedetto, Anna; Santoro, Raffaela; Germoni, Sabrina; De Angelis, Fernanda; Cambria, Anna; Avraham, Roi; Grasso, Giuseppe; Strano, Sabrina; Muti, Paola; Mottolese, Marcella; Yarden, Yosef; Domany, Eytan; Blandino, Giovanni

    2012-11-01

    Deregulated proliferation is a hallmark of cancer cells. Here, we show that microRNA-10b* is a master regulator of breast cancer cell proliferation and is downregulated in tumoural samples versus matched peritumoural counterparts. Two canonical CpG islands (5 kb) upstream from the precursor sequence are hypermethylated in the analysed breast cancer tissues. Ectopic delivery of synthetic microRNA-10b* in breast cancer cell lines or into xenograft mouse breast tumours inhibits cell proliferation and impairs tumour growth in vivo, respectively. We identified and validated in vitro and in vivo three novel target mRNAs of miR-10b* (BUB1, PLK1 and CCNA2), which play a remarkable role in cell cycle regulation and whose high expression in breast cancer patients is associated with reduced disease-free survival, relapse-free survival and metastasis-free survival when compared to patients with low expression. This also suggests that restoration of microRNA-10b* expression might have therapeutic promise.

  8. Uptake of [sup 10]B in gliosarcomas following the injection of gluthathione monoethyl ester and sulfhydryl borane

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Slatkin, D.N.; Coderre, J.A.

    1992-01-01

    The sulfhydryl borane Na[sub 2][sup 10]B[sub 12]H[sub 11]SH (BSH) was developed as a capture agent for BNCT about 20 years ago and is the compound currently used clinically in Japan for BNCT of malignant brain tumors. Tumor [sup 10]B concentrations following the infusion of the oxidized BSH, a disulfide dimer (Na[sub 4][sup 10]B[sub 24]H[sub 22]S[sub 2]), are nearly twice those obtained following administration of equal amounts of boron as BSH. Also, the rate of decrease of tumor [sup 10]B concentration is slower after dimer infusion than after BSH infusion. When BNCT was administered to rats bearing intracerebral gliosarcomas, the animals infused with dimer had a significant longer median survival time. Dimer, on the other hand, induces a moderately severe, but reversible, hepatotoxicity which may complicate its use in humans. Intracellular glutathione plays an important role in defense against radical-mediated tissue injury. Glutathione monoesters have been reported to have a protective effective on cisplatin toxicity and on radical-induced acute pancreatitis. We investigated the possibility of reducing dimer-induced hepatotoxicity by pre-administration of GSH-ME. The results indicate that not only does the pre-administration of GSH-ME markedly reduce dimer-induced hepatotoxicity, but also results in nearly a doubling of tumor boron concentration. Furthermore, GSH-ME markedly increases tumor boron uptake and retention following administration of BSH.

  9. Uptake of {sup 10}B in gliosarcomas following the injection of gluthathione monoethyl ester and sulfhydryl borane

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Slatkin, D.N.; Coderre, J.A.

    1992-12-31

    The sulfhydryl borane Na{sub 2}{sup 10}B{sub 12}H{sub 11}SH (BSH) was developed as a capture agent for BNCT about 20 years ago and is the compound currently used clinically in Japan for BNCT of malignant brain tumors. Tumor {sup 10}B concentrations following the infusion of the oxidized BSH, a disulfide dimer (Na{sub 4}{sup 10}B{sub 24}H{sub 22}S{sub 2}), are nearly twice those obtained following administration of equal amounts of boron as BSH. Also, the rate of decrease of tumor {sup 10}B concentration is slower after dimer infusion than after BSH infusion. When BNCT was administered to rats bearing intracerebral gliosarcomas, the animals infused with dimer had a significant longer median survival time. Dimer, on the other hand, induces a moderately severe, but reversible, hepatotoxicity which may complicate its use in humans. Intracellular glutathione plays an important role in defense against radical-mediated tissue injury. Glutathione monoesters have been reported to have a protective effective on cisplatin toxicity and on radical-induced acute pancreatitis. We investigated the possibility of reducing dimer-induced hepatotoxicity by pre-administration of GSH-ME. The results indicate that not only does the pre-administration of GSH-ME markedly reduce dimer-induced hepatotoxicity, but also results in nearly a doubling of tumor boron concentration. Furthermore, GSH-ME markedly increases tumor boron uptake and retention following administration of BSH.

  10. 76 FR 18761 - Worldwide Logistics Co., Ltd.; Possible Violations of Sections 10(a)(1) and 10(b)(2) of the...

    Science.gov (United States)

    2011-04-05

    ... Worldwide Logistics Co., Ltd.; Possible Violations of Sections 10(a)(1) and 10(b)(2) of the Shipping Act of 1984; Order of Investigation and Hearing Worldwide Logistics Co., Ltd. (Worldwide) is a company based.... It is a part of the Worldwide Logistics Group, said to be one of the leading integrated logistics...

  11. miR-10b*, a master inhibitor of the cell cycle, is down-regulated in human breast tumours

    Science.gov (United States)

    Biagioni, Francesca; Bossel Ben-Moshe, Noa; Fontemaggi, Giulia; Canu, Valeria; Mori, Federica; Antoniani, Barbara; Di Benedetto, Anna; Santoro, Raffaela; Germoni, Sabrina; De Angelis, Fernanda; Cambria, Anna; Avraham, Roi; Grasso, Giuseppe; Strano, Sabrina; Muti, Paola; Mottolese, Marcella; Yarden, Yosef; Domany, Eytan; Blandino, Giovanni

    2012-01-01

    Deregulated proliferation is a hallmark of cancer cells. Here, we show that microRNA-10b* is a master regulator of breast cancer cell proliferation and is downregulated in tumoural samples versus matched peritumoural counterparts. Two canonical CpG islands (5 kb) upstream from the precursor sequence are hypermethylated in the analysed breast cancer tissues. Ectopic delivery of synthetic microRNA-10b* in breast cancer cell lines or into xenograft mouse breast tumours inhibits cell proliferation and impairs tumour growth in vivo, respectively. We identified and validated in vitro and in vivo three novel target mRNAs of miR-10b* (BUB1, PLK1 and CCNA2), which play a remarkable role in cell cycle regulation and whose high expression in breast cancer patients is associated with reduced disease-free survival, relapse-free survival and metastasis-free survival when compared to patients with low expression. This also suggests that restoration of microRNA-10b* expression might have therapeutic promise. PMID:23125021

  12. LaBr3γ-ray spectrometer for detecting 10B in debris of melted nuclear fuel

    Science.gov (United States)

    Koizumi, Mitsuo; Tsuchiya, Harufumi; Kitatani, Fumito; Harada, Hideo; Heyse, Jan; Kopecky, Stefan; Mondelaers, Willy; Paradela, Carlos; Schillebeeckx, Peter

    2016-11-01

    Neutron resonance densitometry has been proposed as a nondestructive analytical method for quantifying special nuclear material (SNM) in the rock- and particle-like debris that is to be removed from the Fukushima Daiichi nuclear power plant. The method is based on neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis combined with prompt-γ-ray analysis (NRCA/PGA). Although quantification of SNM will predominantly rely on NRTA, this will be hampered by the presence of strong neutron-absorbing matrix materials, in particular 10B. Results obtained with NRCA/PGA are used to improve the interpretation of NRTA data. Prompt γ rays originating from the 10B(n, αγ) reaction are used to assess the amount of 10B. The 478 keV γ rays from 10B, however, need to be measured under a high-radiation environment, especially because of 137Cs. To meet this requirement, we developed a well-shaped γ-ray spectrometer consisting of one cylindrical and four rectangular-cuboid LaBr3 scintillators combined with a fast data-acquisition system. Furthermore, to improve the gain stability of the main detector, a special high-voltage divider was developed. Because of the reduction in gain shift, a 3.8% resolution at 662 keV was obtained for long-term measurements. By using the data-acquisition system, which consists of eight 250 MHz digitizers, input signals of over 500 kHz per channel were recorded. The work reported herein demonstrates that, with such a spectrometer, the impact of the Compton edge of 662 keV γ rays from 137Cs is significantly reduced, which allows the 10B amount to be determined with greater sensitivity.

  13. Partial Dynamical Symmetries in Nuclei

    CERN Document Server

    Leviatan, A

    2000-01-01

    Partial dynamical symmetries (PDS) are shown to be relevant to the interpretation of the $K=0_2$ band and to the occurrence of F-spin multiplets of ground and scissors bands in deformed nuclei. Hamiltonians with bosonic and fermionic PDS are presented.

  14. Multiphonon giant resonances in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    1998-07-01

    We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)

  15. Nuclear astrophysics of light nuclei

    DEFF Research Database (Denmark)

    Fynbo, Hans Otto Uldall

    2013-01-01

    A review of nuclear astrophysics of light nuclei using radioactive beams or techniques developed for radioactive beams is given. We discuss Big Bang nucleosynthesis, with special focus on the lithium problem, aspects of neutrino-physics, helium-burning and finally selected examples of studies...

  16. Fission dynamics of hot nuclei

    Indian Academy of Sciences (India)

    Santanu Pal; Jhilam Sadhukhan

    2014-04-01

    Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.

  17. Low energy + scattering on = nuclei

    Indian Academy of Sciences (India)

    Swapan Das; Arun K Jain

    2003-11-01

    The data for the total cross-section of + scattering on various nuclei have been analysed in the Glauber multiple scattering theory. Energy-dependent +-nucleus optical potential is generated using the forward +-nucleon scattering amplitude and the nuclear density distribution. Along with this, the calculated total +-nucleus cross-sections using the effective +-nucleon cross-section inside the nucleus are also presented.

  18. The study of 12C(α,γ astrophysical reaction using 12C(6Li,d and 12C(7Li,t reaction at 20 MeV and in the framework of the potential model

    Directory of Open Access Journals (Sweden)

    Adhikari S.

    2015-01-01

    Full Text Available The triton angular distribution in the 12C(7Li,t16O reaction has been measured at 20 MeV incident energy. Comparison of the data with Finite Range DWBA and CDCC-CRC calculations show that breakup coupling effects are prominent in the transfer to the ground state. This observation is similar to that in the 12C(6Li,d reaction at the same incident energy. The alpha spectroscopic factor of the 16O ground state is determined (Sα=0.25 from a comparison of the measured angular distribution with respect to the CDCC-CRC calculations. The E2 S-factor of the 12C(α,γ reaction at 300 keV in the framework of a potential model is determined to be about 118 keV-barn.

  19. Study of the {sup 10}B(p,α){sup 7}Be reaction through the indirect Trojan Horse method

    Energy Technology Data Exchange (ETDEWEB)

    Puglia, S. M. R., E-mail: puglia@lns.infn.it [INFN Laboratori Nazionali del Sud and CSFNM-Centrosiciliano Fisica Nucleare e Struttura della Materia,Catania (Italy); Spitaleri, C.; Lamia, L.; Romano, S.; La Cognata, M.; Pizzone, R. G.; Rapisarda, G. G.; Sergi, M. L. [INFN Laboratori Nazionali del Sud and DMFCI- Università di Catania, Catania (Italy); Burjan, V.; Kroha, V.; Hons, Z.; Mrazek, J. [Institute for Nuclear Physics, Prague-Rez (Czech Republic); Carlin, N.; Del Santo, M. G.; Munhoz, M. G.; Souza, F.; Szanto de Toledo, A. [Universidade de São Paulo - DFN, São Paulo (Brazil); Chengbo, L.; Qungang, W.; Shu-Hua, Z. [China Institute of Atomic Energy, Beijing (China); and others

    2015-02-24

    Boron abundances in stellar atmospheres, as well as berillium and lithium ones, can give useful hints for non-standard transport processes discrimination in stars. They can also be relevant for understanding several astrophysical processes (e.g. primordial nucleosynthesis and spallation reactions in ISM). A comprehensive study of Li Be B abundances can therefore confirm or not the presence of non-standard mixing processes in stellar envelopes. For this reason nuclear processes producing or depleting boron isotope abundance need to be studied at astrophysical energies. The {sup 10}B(p,α){sup 7}Be reaction has been studied by means of the Trojan Horse Method. The Trojan Horse Method was thus applied to the {sup 10}B(d,α{sup 7}Be)n reaction, studied at 24 MeV. The obtained results will be discussed.

  20. Unusual Multiple Production of N-Acylhomoserine Lactones a by Burkholderia sp. Strain C10B Isolated from Dentine Caries

    Directory of Open Access Journals (Sweden)

    Share Yuan Goh

    2014-05-01

    Full Text Available Bacteria realize the ability to communicate by production of quorum sensing (QS molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs. This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL, N-octanoyl-L-homoserine lactone (C8-HSL, N-decanoyl-L-homoserine lactone (C10-HSL and N-dodecanoyl-L-homoserine lactone (C12-HSL.

  1. Scissors Mode in Gd Nuclei

    Directory of Open Access Journals (Sweden)

    Wu C.Y.

    2012-02-01

    Full Text Available Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  2. Scissors Mode in Gd Nuclei

    Science.gov (United States)

    Kroll, J.; Baramsai, B.; Becker, J. A.; Bečvář, F.; Bredeweg, T. A.; Couture, A.; Chyzh, A.; Dashdorj, D.; Haight, R. C.; Jandel, M.; Krtička, M.; Mitchell, G. E.; O'Donnell, J. M.; Parker, W.; Rundberg, R. S.; Ullmann, J. L.; Vieira, G. J.; Walker, C. L.; Wilhelmy, J. B.; Wouters, J. M.; Wu, C. Y.

    2012-02-01

    Spectra of γ rays following neutron capture at isolated resonances of 6 stable Gd isotopes were measured with highly segmented BaF2 detector DANCE at the Los Alamos LANSCE spallation neutron source. The main emphasis was put on studying the γ-cascade decay of neutron resonances to get unique information on photon strength. An analysis of the accumulated γ-ray spectra within the extreme statistical model leads to an inescapable conclusion that scissors mode resonances are built not only on the ground-state, but also on excited levels in all product nuclei studied. The results on summed B(M1)↑ strength and energy of the scissors mode are compared with systematics of scissors mode parameters for the ground-state transitions deduced from nuclear resonance fluorescence measurements. A specific feature of our experiments is the investigation of scissors mode of odd nuclei, for which the nuclear resonance fluorescence provides only limited information.

  3. Evolution of active galactic nuclei

    CERN Document Server

    Merloni, Andrea

    2012-01-01

    [Abriged] Supermassive black holes (SMBH) lurk in the nuclei of most massive galaxies, perhaps in all of them. The tight observed scaling relations between SMBH masses and structural properties of their host spheroids likely indicate that the processes fostering the growth of both components are physically linked, despite the many orders of magnitude difference in their physical size. This chapter discusses how we constrain the evolution of SMBH, probed by their actively growing phases, when they shine as active galactic nuclei (AGN) with luminosities often in excess of that of the entire stellar population of their host galaxies. Following loosely the chronological developments of the field, we begin by discussing early evolutionary studies, when AGN represented beacons of light probing the most distant reaches of the universe and were used as tracers of the large scale structure. This early study turned into AGN "Demography", once it was realized that the strong evolution (in luminosity, number density) of ...

  4. Microstructural evolution of HFIR-irradiated low activation F82H and F82H-{sup 10}B steels

    Energy Technology Data Exchange (ETDEWEB)

    Wakai, E.; Shiba, K.; Sawai, T. [Japan Atomic Energy Research Inst. (Japan); Hashimoto, N.; Robertson, J.P.; Klueh, R.L. [Oak Ridge National Lab., TN (United States)

    1998-03-01

    Microstructures of reduced-activation F82H (8Cr-2W-0.2V-0.04Ta) and the F82H steels doped with {sup 10}B, irradiated at 250 and 300 C to 3 and 57 dpa in the High Flux Isotope Reactor (HFIR), were examined by TEM. In the F82H irradiated at 250 C to 3 dpa, dislocation loops, small unidentified defect clusters with a high number density, and a few MC precipitates were observed in the matrix. The defect microstructure after 300 C irradiation to 57 dpa is dominated by the loops, and the number density of loops was lower than that of the F82H-{sup 10}B steel. Cavities were observed in the F82H-{sup 10}B steels, but the swelling value is insignificant. Small particles of M{sub 6}C formed on the M{sub 23}C{sub 6} carbides that were present in both steels before the irradiation at 300 C to 57 dpa. A low number density of MC precipitate particles formed in the matrix during irradiation at 300 C to 57 dpa.

  5. CoRoT-10b: a giant planet in a 13.24 day eccentric orbit

    CERN Document Server

    Bonomo, A S; Alonso, R; Gazzano, J -C; Havel, M; Aigrain, S; Auvergne, M; Baglin, A; Barbieri, M; Barge, P; Benz, W; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Cameron, A C; Carone, L; Carpano, S; Csizmadia, Sz; Deleuil, M; Deeg, H J; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gillon, M; Guenther, E; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Lammer, H; Lanza, A F; Léger, A; Llebaria, A; Mayor, M; Mazeh, T; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Tingley, B; Udry, S; Wuchterl, G

    2010-01-01

    The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view. We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e=0.53 +/- 0.04) revolving in 13.24 days around a faint (V=15.22) metal-rich K1V star. We use CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star to derive the orbital, stellar and planetary parameters. We derive a radius of the planet of 0.97 +/- 0.07 R_Jup and a mass of 2.75 +/- 0.16 M_Jup. The bulk density, rho_pl=3.70 +/- 0.83 g/cm^3, is ~2.8 that of Jupiter. The core of CoRoT-10b could contain up to 240 M_Earth of heavy elements. Moving along its eccentric orbit, the planet experiences a 10.6-fold variation in insolation. Owing to the long circularisation time, tau_circ > 7 Gyr, a resonant perturber is not required to excite and maintain the high eccentricity of CoRoT-10b.

  6. Proton scattering from unstable nuclei

    Indian Academy of Sciences (India)

    Y Blumenfeld; E Khan; F Maréchal; T Suomijärvi

    2001-08-01

    Recent improvements in the intensities and optical qualities of radioactive beams have made possible the study of elastic and inelastic proton scattering on unstable nuclei. The design and performances of an innovative silicon strip detector array devoted to such experiments are described. The quality of the data obtained are illustrated with recent results obtained at the GANIL facility for unstable oxygen, sulfur and argon isotopes. Methods to analyse the data using phenomenological and microscopic optical model potentials are discussed.

  7. Strange neutral currents in nuclei

    CERN Document Server

    Ressell, M T; Aufderheide, M B; Bloom, S D; Resler, D A

    1995-01-01

    We examine the effects on the nuclear neutral current Gamow-Teller (GT) strength of a finite contribution from a polarized strange quark sea. We perform nuclear shell model calculations of the neutral current GT strength for a number of nuclei likely to be present during stellar core collapse. We compare the GT strength when a finite strange quark contribution is included to the strength without such a contribution. As an example, the process of neutral current nuclear de-excitation via \

  8. Weak pion production from nuclei

    Indian Academy of Sciences (India)

    S K Singh; M Sajjad Athar; Shakeb Ahmad

    2006-04-01

    The charged current pion production induced by neutrinos in 12C, 16O and 56Fe nuclei has been studied. The calculations have been done for the coherent as well as the incoherent processes assuming dominance and takes into account the effect of Pauli blocking, Fermi motion and the renormalization of in the nuclear medium. The pion absorption effects have also been taken into account.

  9. Triaxial rotation in atomic nuclei

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-Shou; GAO Zao-Chun

    2009-01-01

    The Projected Shell Model has been developed to include the spontaneously broken axial symmetry so that the rapidly rotating triaxial nuclei can be described microscopically. The theory provides an useful tool to gain an insight into how a triaxial nucleus rotates, a fundamental question in nuclear structure. We shall address some current interests that are strongly associated with the triaxial rotation. A feasible method to explore the problem has been suggested.

  10. Double pion photoproduction in nuclei

    CERN Document Server

    Vicente-Vacas, M J; Gómez-Tejedor, J A; Vicente-Vacas, M J; Oset, E; Gómez Tejedor, J A

    1994-01-01

    Abstract: The inclusive A(gamma,pi+ pi-)X reaction is studied theoretically. A sizeable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section (sigma_deuteron * A/2). This enhancement is due to the modifications in the nuclear medium of the gamma N ----> pi pi N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the (pi,pi pi) reaction in nuclei.

  11. Continuum spectroscopy of light nuclei

    Directory of Open Access Journals (Sweden)

    Charity R. J.

    2016-01-01

    Full Text Available Resonance spectroscopy of light nuclei is discussed with emphasis on the invariant-mass measurements performed with the HiRA detector. For three-body exit channels, we consider the exact conditions necessary such that the decay can be described as either sequential or prompt. However experimentally, we find some cases where the decay is intermediate between these two limits. Finally, two-proton decay from isobaric analog states is discussed.

  12. Geometric symmetries in light nuclei

    CERN Document Server

    Bijker, Roelof

    2016-01-01

    The algebraic cluster model is is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles.

  13. 17 CFR 240.10b5-1 - Trading “on the basis of” material nonpublic information in insider trading cases.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Trading âon the basis ofâ material nonpublic information in insider trading cases. 240.10b5-1 Section 240.10b5-1 Commodity and... Deceptive Devices and Contrivances § 240.10b5-1 Trading “on the basis of” material nonpublic information...

  14. Tensor Effect on Bubble Nuclei

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-Zhao; GU Jian-Zhong; ZHANG Xi-Zhen; DONG Jian-Min

    2011-01-01

    In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+Tw and several sets of TIJ parametrizations, I.e. The Skyrme interaction parametrizations including the tensor terms, the proton density distribution in 34Si and 46Ar nuclei is calculated with and without the tensor force. It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force. As to 46Ar, the SLy5+Tw parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-ld3/2 inversion). The inversion mechanism induced by the SLy5+Tw interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+Tw interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.%In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+ T,SLy5+ Tω and several sets of TIJ parametrizations,i.e.the Skyrme interaction pararmetrizations including the tensor terms,the proton density distribution in 34Si and 46 Ar nuclei is calculated with and without the tensor force.It is shown that the bubble effect in 34Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in 34Si is hardly influenced by the tensor force.As to 46Ar,the SLy5+ Tω parametrization favors the formation of the bubble structure due to the inversion between the 2s1/2 and 1d3/2 orbits (2s1/2-1d3/2 inversion).The inversion mechanism induced by the SLy5+ Tω interaction is analyzed based on the proton single-particle spectra obtained from the SLy5 and SLy5+ Tω interactions as well as the wave functions of the 2s1/2 and 1d3/2 states.The study of exotic nuclear structures has been a hot topic in nuclear physics.[1-4] Exotic nuclei are unstabile,superheavy nuclei,halo nuclei and so forth,whose structures are quite different

  15. Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

    Science.gov (United States)

    Leitzinger, M; Odert, P; Kulikov, Yu N; Lammer, H; Wuchterl, G; Penz, T; Guarcello, M G; Micela, G; Khodachenko, M L; Weingrill, J; Hanslmeier, A; Biernat, H K; Schneider, J

    2011-10-01

    We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a "Hot Neptune" nor a "Hot Uranus"-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects.

  16. Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?

    Science.gov (United States)

    Leitzinger, M.; Odert, P.; Kulikov, Yu.N.; Lammer, H.; Wuchterl, G.; Penz, T.; Guarcello, M.G.; Micela, G.; Khodachenko, M.L.; Weingrill, J.; Hanslmeier, A.; Biernat, H.K.; Schneider, J.

    2011-01-01

    We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects. PMID:21969736

  17. Rule 10b-5 and Reasonable Reliance: Why Courts Should Abandon Focus on Non-Reliance Clauses

    Directory of Open Access Journals (Sweden)

    Jonathan P. Altman

    2007-04-01

    Full Text Available In a typical privately negotiated merger or acquisition, the parties involved will be engaged in months of negotiations prior to the closing of their deal. Over the course of such, many projections, agreements, documents, oral representations and warranties (hereinafter “information” will undoubtedly be exchanged by both sides. In the final purchase agreement, a seller typically lists detailed representations and warranties about its business, and includes a proviso that the buyer is not relying on any other information. Inclusion of this “non-reliance clause” (hereinafter “NRC” is intended to restrict a buyer’s ability to bring a fraud claim under Rule 10b-5.

  18. The 10B based Jalousie neutron detector - An alternative for 3He filled position sensitive counter tubes

    Science.gov (United States)

    Henske, M.; Klein, M.; Köhli, M.; Lennert, P.; Modzel, G.; Schmidt, C. J.; Schmidt, U.

    2012-09-01

    Over the last decades 3He filled proportional counter tubes were the working horse employed to serve as neutron counters especially in cases where large area coverage was required. Today the lack of 3He demands the development of an alternative technology. Here we present a prototype neutron detector that is based on a concept with solid 10B as neutron converter and aims for large area neutron detection applications. We report on first experimental results obtained with this prototype to demonstrate the feasibility and operational readiness of our concept.

  19. The {sup 10}B based Jalousie neutron detector - An alternative for {sup 3}He filled position sensitive counter tubes

    Energy Technology Data Exchange (ETDEWEB)

    Henske, M. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); Klein, M., E-mail: martin.klein@physi.uni-heidelberg.de [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); Koehli, M.; Lennert, P.; Modzel, G. [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Schmidt, C.J. [CDT CASCADE Detector Technologies GmbH, Hans-Bunte-Str. 8-10, 69123 Heidelberg (Germany); GSI Detector Laboratory, Planckstrasse 1, 64291 Darmstadt (Germany); Schmidt, U. [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

    2012-09-11

    Over the last decades {sup 3}He filled proportional counter tubes were the working horse employed to serve as neutron counters especially in cases where large area coverage was required. Today the lack of {sup 3}He demands the development of an alternative technology. Here we present a prototype neutron detector that is based on a concept with solid {sup 10}B as neutron converter and aims for large area neutron detection applications. We report on first experimental results obtained with this prototype to demonstrate the feasibility and operational readiness of our concept.

  20. Microscopic properties of superdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Lennart B

    1999-04-01

    Many high spin rotational bands in superdeformed nuclei have been found in the A 140 - 150 region, but so far no linking transitions to known normal-deformed states have been found in these nuclei. Therefore, configuration and spin assignments have to be based on indirect spectroscopic information. Identical bands were first discovered in this region of superdeformed states. At present, some identical bands have also been found at normal deformation, but such bands are more common at superdeformation. Recently lifetime measurements have given relative quadrupole moments with high accuracy. Spectroscopic quantities are calculated using the configuration constrained cranked Nilsson-Strutinsky model with the modified oscillator potential. In a statistical study the occurrence of identical bands is tested. Comparing superdeformed and normal deformed nuclei, the higher possibility for identical bands at superdeformation is understood from calculated reduced widths of the E{sub {gamma}} and J{sup (2)} distributions. The importance of high-N orbitals for identical bands is also discussed. Additivity of electric quadrupole moment contributions in the superdeformed A - 150 region is discussed with the nucleus {sup 152}Dy as a `core`. In analytic harmonic oscillator calculations, the effective electric quadrupole moment q{sub eff}, i.e. the change in the total quadrupole moment caused by the added particle, is expressed as a simple function of the single-particle mass, quadrupole moment q{sub {nu}}. Also in realistic calculations, simple relations between q{sub eff} and q{sub {nu}} can be used to estimate the total electric quadrupole moment, e.g. for the nucleus {sup 142}Sm, by adding the effect of 10 holes, to the total electric quadrupole moment of {sup 152}Dy. Furthermore, tools are given for estimating the quadrupole moment for possible configurations in the superdeformed A - 150 region. For the superdeformed region around {sup 143}Eu, configuration and spin assignments

  1. Breakup Densities of Hot Nuclei.

    Science.gov (United States)

    Viola, Vic

    2006-04-01

    Breakup densities of hot ^197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E*/A .3ex˜x 5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios.

  2. Double pion photoproduction in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Tejedor, J.A. [Departamento de Fisica Teorica, Valencia (Spain); Vicente-Vacas, M.J. [Departamento de Fisica Teorica, Valencia (Spain); Oset, E. [Departamento de Fisica Teorica, Valencia (Spain)

    1995-06-19

    The inclusive A({gamma},{pi}{sup +}{pi}{sup -})X reaction is studied theoretically. A sizable enhancement of the cross section is found, in comparison with the scaling of the deuteron cross section ({sigma}{sub d} A/2). This enhancement is due to the modifications in the nuclear medium of the {gamma}N {yields}{pi}{pi}N amplitude and the pion dispersion relation. The enhancement is found to be bigger than the one already observed in the ({pi},{pi}{pi}) reaction in nuclei. ((orig.)).

  3. Monte-Carlo simulation of primary stochastic effects induced at the cellular level in boron neutron capture therapy; Simulation Monte-Carlo des effets stochastiques primaires induits au niveau cellulaire lors de la therapie par capture de neutrons sur le {sup 10}B

    Energy Technology Data Exchange (ETDEWEB)

    Cirioni, L.; Patau, J.P.; Nepveu, F. [Universite Paul Sabatier, 31 - Toulouse (France)

    1998-04-01

    A Monte Carlo code is developed to study the action of particles in Boron Neutron Capture Therapy (BNCT). Our aim is to calculate the probability of dissipating a lethal dose in cell nuclei. Cytoplasmic and nuclear membranes are considered as non-concentric ellipsoids. All geometrical parameters may be adjusted to fit actual configurations. The reactions {sup 10}B(n,{gamma} {alpha}){sup 7}Li and {sup 14}N(n,p) {sup 14}C create heavy ions which slow clown losing their energy. Their trajectories can be simulated taking into account path length straggling. The contribution of each reaction to the deposited dose in different cellular compartments can be studied and analysed for any distribution of {sup 10}B. (authors)

  4. Neutron-pair emission following pi /sup -/ absorption on some light nuclei

    CERN Document Server

    Furic, M; Engelhardt, H D; Klotz, W D; Takeutchi, F; Ullrich, H

    1977-01-01

    Large-area position-sensitive neutron counters with subnanosecond time resolution have been used to study the ( pi /sup -/,2n) reaction with a resolution comparable to or better than the existing ( pi /sup + /,2p) data. The measurement of the momenta of both neutrons enabled a determination of the excitation energy spectra of the residual nuclei to be made. The momentum distributions for the absorbing nucleon pair were also extracted assuming the quasifree mechanism for the ( pi /sup -/,2n) process. The pi /sup -/ beam obtained from the CERN SC II was brought to rest in the targets of /sup 9/Be, /sup 10/B, /sup 12/C and /sup 14/N. The excitation spectra of the residual nuclei were compared with the predictions based on the coefficients of fractional parentage for the removal of the two nucleons. The data and the predictions are in good agreement within the experimental resolution. (4 refs).

  5. Pairing correlations in exotic nuclei

    CERN Document Server

    Sagawa, H

    2012-01-01

    The BCS and HFB theories which can accommodate the pairing correlations in the ground states of atomic nuclei are presented. As an application of the pairing theories, we investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a 3-body model, respectively. We show that the odd-even staggering in the reaction cross sections of $^{30,31,32}$Ne and $^{14,15,16}$C are successfully reproduced, and thus the staggering can be attributed to the unique role of pairing correlations in nuclei far from the stability line. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for $s$- and p-waves using the HFB wave functions. We also propose effective density-dependent pairing interactions which reproduce both the neutron-neutron ($nn$) scattering length at zero density and the neutron pairing gap in uniform matter. Then, we apply these interactions to study pairing gaps in ...

  6. Selfconsistent calculations for hyperdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Molique, H.; Dobaczewski, J.; Dudek, J.; Luo, W.D. [Universite Louis Pasteur, Strasbourg (France)

    1996-12-31

    Properties of the hyperdeformed nuclei in the A {approximately} 170 mass range are re-examined using the self-consistent Hartree-Fock method with the SOP parametrization. A comparison with the previous predictions that were based on a non-selfconsistent approach is made. The existence of the {open_quotes}hyper-deformed shell closures{close_quotes} at the proton and neutron numbers Z=70 and N=100 and their very weak dependence on the rotational frequency is suggested; the corresponding single-particle energy gaps are predicted to play a role similar to that of the Z=66 and N=86 gaps in the super-deformed nuclei of the A {approximately} 150 mass range. Selfconsistent calculations suggest also that the A {approximately} 170 hyperdeformed structures have neglegible mass asymmetry in their shapes. Very importantly for the experimental studies, both the fission barriers and the {open_quotes}inner{close_quotes} barriers (that separate the hyperdeformed structures from those with smaller deformations) are predicted to be relatively high, up to the factor of {approximately}2 higher than the corresponding ones in the {sup 152}Dy superdeformed nucleus used as a reference.

  7. Thermal instability of cell nuclei

    Science.gov (United States)

    Warmt, Enrico; Kießling, Tobias R.; Stange, Roland; Fritsch, Anatol W.; Zink, Mareike; Käs, Josef A.

    2014-07-01

    DNA is known to be a mechanically and thermally stable structure. In its double stranded form it is densely packed within the cell nucleus and is thermo-resistant up to 70\\:^\\circ {\\rm{C}}. In contrast, we found a sudden loss of cell nuclei integrity at relatively moderate temperatures ranging from 45 to 55\\:^\\circ {\\rm{C}}. In our study, suspended cells held in an optical double beam trap were heated under controlled conditions while monitoring the nuclear shape. At specific critical temperatures, an irreversible sudden shape transition of the nuclei was observed. These temperature induced transitions differ in abundance and intensity for various normal and cancerous epithelial breast cells, which clearly characterizes different cell types. Our results show that temperatures slightly higher than physiological conditions are able to induce instabilities of nuclear structures, eventually leading to cell death. This is a surprising finding since recent thermorheological cell studies have shown that cells have a lower viscosity and are thus more deformable upon temperature increase. Since the nucleus is tightly coupled to the outer cell shape via the cytoskeleton, the force propagation of nuclear reshaping to the cell membrane was investigated in combination with the application of cytoskeletal drugs.

  8. Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

    CERN Document Server

    Anders, M; Bellini, A; Aliotta, M; Bemmerer, D; Broggini, C; Caciolli, A; Costantini, H; Corvisiero, P; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D; Somorjai, E; Straniero, O; Szücs, T

    2013-01-01

    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction....

  9. Evaluation of two thermal neutron detection units consisting of ZnS/${}^6$LiF scintillating layers with embedded WLS fibers read out with a SiPM

    CERN Document Server

    Mosset, J -B; Greuter, U; Hildebrandt, M; Schlumpf, N; Van Swygenhoven, H

    2014-01-01

    Two single channel detection units for thermal neutron detection are investigated in a neutron beam. They consist of two ZnS/${}^6$LiF scintillating layers sandwiching an array of WLS fibers. The pattern of this units can be repeated laterally and vertically in order to build up a one dimensional position sensitive multi-channel detector with the needed sensitive surface and with the required neutron absorption probability. The originality of this work arises from the fact that the WLS fibers are read out with SiPMs instead of the traditionally used PMTs or MaPMTs. The signal processing system is based on a photon counting approach. For SiPMs with a dark count rate as high as 0.7 MHz, a trigger efficiency of 80% is achieved together with a system background rate lower than ${10}^{-3}$ Hz and a dead time of 30 $\\mu$s. No change of performance is observed for neutron count rates of up to 3.6 kHz.

  10. Excited nuclei in neutron star crusts

    CERN Document Server

    Takibayev, Nurgali; Nasirova, Diana

    2012-01-01

    The paper considers the chains of successive electron capture reactions by nuclei of the iron group which take place in the crystal structures of neutron star envelopes. It is shown that as a result of such reactions the daughter nuclei in excited states accumulate within certain layers of neutron star crusts. The phonon model of interactions is proposed between the excited nuclei in the crystalline structure, as well as formation of highly excited nuclear states which emit neutrons and higher energy photons.

  11. Tailored Nanoparticle Codelivery of antimiR-21 and antimiR-10b Augments Glioblastoma Cell Kill by Temozolomide: Toward a "Personalized" Anti-microRNA Therapy.

    Science.gov (United States)

    Ananta, Jeyarama S; Paulmurugan, Ramasamy; Massoud, Tarik F

    2016-09-01

    Glioblastoma remains an aggressive brain malignancy with poor prognosis despite advances in multimodal therapy that include standard use of Temozolomide. MicroRNA-21 (miR-21) and microRNA-10b (miR-10b) are oncomiRs overexpressed in glioblastoma, promoting many aspects of cancer biology. We hypothesized that PLGA nanoparticles carrying antisense miR-21 (antimiR-21) and antisense miR-10b (antimiR-10b) might beneficially knockdown endogenous miR-21 and miR-10b function and reprogram cells prior to Temozolomide treatment. PLGA nanoparticles were effective in intracellular delivery of encapsulated oligonucleotides. Concentrations of delivered antimiR-21 and antimiR-10b were optimized and specifically tailored to copy numbers of intracellular endogenous microRNAs. Coinhibition of miR-21 and miR-10b significantly reduced the number of viable cells (by 24%; p < 0.01) and increased (2.9-fold) cell cycle arrest at G2/M phase upon Temozolomide treatment in U87 MG cells. Cell-tailored nanoparticle-assisted concurrent silencing of miR-21 and miR-10b prior to Temozolomide treatment is an effective molecular therapeutic strategy in cell culture, warranting the need for further studies prior to future in vivo "personalized" medicine applications.

  12. Review of metastable states in heavy nuclei

    Science.gov (United States)

    Dracoulis, G. D.; Walker, P. M.; Kondev, F. G.

    2016-07-01

    The structure of nuclear isomeric states is reviewed in the context of their role in contemporary nuclear physics research. Emphasis is given to high-spin isomers in heavy nuclei, with A≳ 150 . The possibility to exploit isomers to study some of the most exotic nuclei is a recurring theme. In spherical nuclei, the role of octupole collectivity is discussed in detail, while in deformed nuclei the limitations of the K quantum number are addressed. Isomer targets and isomer beams are considered, along with applications related to energy storage, astrophysics, medicine, and experimental advances.

  13. Local chiral potentials with Δ-intermediate states and the structure of light nuclei

    Science.gov (United States)

    Piarulli, Maria

    2017-01-01

    We present a fully local nucleon-nucleon potential in chiral effective field theory (χEFT) retaining pions, nucleons and Δ-isobars as explicit degrees of freedom, and use it in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of 3H, 3He, 4He, 6He, and 6Li nuclei. The calculation of the potential is carried out by including one- and two-pion-exchange contributions up to next-to-next-to-leading order (N2LO) and contact interactions up to next-to-next-to-next-to-leading order (N3LO). The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0-125 MeV or 0-200 MeV, and to the deuteron binding energy and nn singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, RL and RS respectively, ranging from (RL ,RS) =(1 . 2 , 0 . 8) fm down to (0 . 8 , 0 . 6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.

  14. Cavitation Nuclei: Experiments and Theory

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfven said: Theories come and go - the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory...... becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer...... us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....

  15. CAVITATION NUCLEI: EXPERIMENTS AND THEORY

    Institute of Scientific and Technical Information of China (English)

    MфRCH K. A.

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfvén said: Theories come and go ─ the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories – and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character.

  16. Inclusive breakup of Borromean nuclei

    CERN Document Server

    Hussein, Mahir S; Frederico, Tobias

    2016-01-01

    We derive the inclusive breakup cross section of a three-fragment projectile nuclei, $a = b +x_1 + x_2$, in the spectator model. The resulting four-body cross section for observing $b$, is composed of the elastic breakup cross section which contains information about the correlation between the two participant fragments, and the inclusive non-elastic breakup cross section. This latter cross section is found to be a non-trivial four-body generalization of the Austern formula \\cite{Austern1987}, which is proportional to a matrix element of the form, $\\langle\\hat{\\rho}_{{x_1},{x_2}}\\left|\\left[W_{{x_1}} + W_{{x_2}} + W_{3B}\\right]\\right|\\hat{\\rho}_{{x_1}, {x_2}}\\rangle$. The new feature here is the three-body absorption, represented by the imaginary potential, $W_{3B}$. We analyze this type of absorption and supply ideas of how to calculate its contribution.

  17. Formation of $\\phi$ mesic nuclei

    CERN Document Server

    Yamagata-Sekihara, J; Vacas, M J Vicente; Hirenzaki, S

    2010-01-01

    We study the structure and formation of the $\\phi$ mesic nuclei to investigate the in-medium modification of the $\\phi$-meson spectral function at finite density. We consider (${\\bar p},\\phi$), ($\\gamma,p$) and ($\\pi^-,n$) reactions to produce a $\\phi$-meson inside the nucleus and evaluate the effects of its medium modifications to the reaction cross sections. We also estimate the consequences of the uncertainties of the ${\\bar K}$ selfenergy in medium to the $\\phi$-nucleus interaction. We find that it may be possible to see a peak structure in the reaction spectra for the strong attractive potential cases. On the other hand, for strong absorptive interaction cases with relatively weak attractions, it is very difficult to observe clear peaks and we may need to know the spectrum shape in a wide energy region to deduce the properties of $\\phi$.

  18. Quasifree kaon photoproduction on nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Frank Lee; T. MART; Cornelius Bennhold; Lester Wright

    2001-12-01

    Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.

  19. Novel and efficient {sup 10}B lined tubelet detector as a replacement for {sup 3}He neutron proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Tsorbatzoglou, Kyriakos [Centronic LLC, 16203 Park Row, Houston, TX 77084 (United States); McKeag, Robert D., E-mail: info@centronic.us [Centronic Limited, Centronic House, King Henry' s Drive, Croydon CR9 0BG (United Kingdom)

    2011-10-01

    This paper presents a novel and robust proportional detector which addresses the well publicized shortage of {sup 3}He gas by using a {sup 10}B lining applied to a tubelet configuration. The advantage of the tubelet structure is that it yields a detector maintaining the form factor of a conventional {sup 3}He tube whilst achieving a sensitivity of up to 75% of a 3 atm {sup 3}He device. The design and fabrication of the tubelet detector is presented and discussed with test data comparing the new detector to existing {sup 3}He and BF{sub 3} tubes. The application of the tubelet design to security and industrial applications including retro-fitting to existing portals and suitability for high integrity oil and gas installations is addressed.

  20. Cluster correlation effects in 12C+12C and 14N+10B fusion-evaporation reactions

    Directory of Open Access Journals (Sweden)

    Morelli L.

    2015-01-01

    Full Text Available The decay of highly excited states of 24Mg is studied in fusion evaporation events completely detected in charge in the reactions 12C+12C and 14N+10B at 95 and 80 MeV incident energy respectively. The comparison of light charged particles measured spectra with statistical model predictions suggests that the dominant reaction mechanism is compound nucleus (CN formation and decay. However, in both reactions, a discrepancy with statistical expectations is found for α particles detected in coincidence with Carbon, Oxigen and Neon residues. The comparison between the two reactions shows that this discrepancy is only partly explained by an entrance channel effect. Evidence for cluster correlations in excited 24Mg CN is suggested by the comparison between the measured and calculated branching ratios for the channels involving α particles.

  1. {sup 4}H-SiC neutron sensors based on ion implanted {sup 10}B neutron converter layer

    Energy Technology Data Exchange (ETDEWEB)

    Issa, F.; Ottaviani, L.; Vervisch, V.; Ferone, R.; Palais, O. [Universite Aix-Marseille, Marseille 13397, (France); Szalkai, D.; Klix, A. [Karlsruhe Institute of Technology, Institute of Neutron Physics and Reactor Technology, Karlsruhe 76344, (Germany); Vermeeren, L. [SCK-CEN, B-2400 Mol, (Belgium); Lyoussi, A. [Laboratoire Dosimetrie Capteurs Instrumentation, CEA, Cadarache 13108, (France); Kuznetsov, A. [University of Oslo, NO-0316 Oslo, (Norway); Lazar, M. [AMPERE, UMR 500, INSA de Lyon, 69621 Villeurbanne, (France); Hallen, A. [KTH, Electrum 229, 16440 Kista, (Sweden)

    2015-07-01

    In the framework of the I{sub S}MART project the main aim is to develop an innovative complete radiation detection system based on silicon carbide technology in view to detect neutrons (thermal and fast) and photons for harsh environments. In the present work two geometries have been realized based on ion implantation of boron. In the first geometry, {sup 10}B ions have been implanted into the Al metallic contact to create the neutron converter layer. In the second geometry one single process has been used to realize both the p+-layer and the neutron converter layer. The technological processes followed to fabricate these detectors, with a study of their electrical behavior and their responses under thermal neutron irradiations are addressed in this paper. (authors)

  2. Set-up and calibration of a method to measure 10B concentration in biological samples by neutron autoradiography

    Science.gov (United States)

    Gadan, M. A.; Bortolussi, S.; Postuma, I.; Ballarini, F.; Bruschi, P.; Protti, N.; Santoro, D.; Stella, S.; Cansolino, L.; Clerici, A.; Ferrari, C.; Zonta, A.; Zonta, C.; Altieri, S.

    2012-03-01

    A selective uptake of boron in the tumor is the base of Boron Neutron Capture Therapy, which can destroy the tumor substantially sparing the normal tissue. In order to deliver a lethal dose to the tumor, keeping the dose absorbed by normal tissues below the tolerance level, it is mandatory to know the 10B concentration present in each kind of tissue at the moment of irradiation. This work presents the calibration procedure adopted for a boron concentration measurement method based on neutron autoradiography, where biological samples are deposited on sensitive films and irradiated in the thermal column of the TRIGA reactor (University of Pavia). The latent tracks produced in the film by the charged particles coming from the neutron capture in 10B are made visible by a proper etching, allowing the measurement of the track density. A calibration procedure with standard samples provides curves of track density as a function of boron concentration, to be used in the measurement of biological samples. In this paper, the bulk etch rate parameter and the calibration curves obtained for both liquid samples and biological tissues with known boron concentration are presented. A bulk etch rate value of (1.64 ± 0.02) μm/h and a linear dependence with etching time were found. The plots representing the track density versus the boron concentration in a range between 5 and 50 μg/g (ppm) are linear, with an angular coefficient of (1.614 ± 0.169)·10-3 tracks/(μm2 ppm) for liquids and (1.598 ± 0.097)·10-2 tracks/(μm2 ppm) for tissues.

  3. Decay of heavy and superheavy nuclei

    Indian Academy of Sciences (India)

    K P Santhosh

    2014-04-01

    We present here, an overview and progress of the theoretical works on the isomeric state decay, decay fine structure of even–even, even–odd, odd–even and odd–odd nuclei, a study on the feasibility of observing decay chains from the isotopes of the superheavy nuclei = 115 in the range 271 ≤ ≤ 294 and the isotopes of = 117 in the range 270 ≤ ≤ 301, within the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The computed half-lives of the favoured and unfavoured decay of nuclei in the range 67 ≤ ≤ 91 from both the ground state and isomeric state, are in good agreement with the experimental data and the standard deviation of half-life is found to be 0.44. From the fine structure studies done on various ranges of nuclei, it is evident that, for nearly all the transitions, the theoretical values show good match with the experimental values. This reveals that CPPMDN is successful in explaining the fine structure of even–even, even–odd, odd–even and odd–odd nuclei. Our studies on the decay of the superheavy nuclei 271−294115 and 270−301117 predict 4 chains consistently from 284,285,286115 nuclei and 5 chains and 3 chains consistently from 288−291117 and 292117, respectively. We thus hope that these studies on 284−286115 and 288−292117 will be a guide to future experiments.

  4. Isovector multiphonon excitations in near spherical nuclei

    CERN Document Server

    Smirnova, N A; Pietralla, N; Van Isacker, P; Isacker, Piet Van; Mizusaki, Takahiro; Pietralla, Norbert; Smirnova, Nadya A.

    2000-01-01

    The lowest isoscalar and isovector quadrupole and octupole excitations in near spherical nuclei are studied within the the proton-neutron version of the interacting boson model including quadrupole and octupole bosons (sdf-IBM-2). The main decay modes of these states in near spherical nuclei are discussed.

  5. Partial Dynamical Symmetry in Deformed Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel)

    1996-07-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei. {copyright} {ital 1996 The American Physical Society.}

  6. Partial dynamical symmetry in deformed nuclei

    CERN Document Server

    Leviatan, A

    1996-01-01

    We discuss the notion of partial dynamical symmetry in relation to nuclear spectroscopy. Explicit forms of Hamiltonians with partial SU(3) symmetry are presented in the framework of the interacting boson model of nuclei. An analysis of the resulting spectrum and electromagnetic transitions demonstrates the relevance of such partial symmetry to the spectroscopy of axially deformed nuclei.

  7. Positron production in collision of heavy nuclei

    CERN Document Server

    Khriplovich, I B

    2016-01-01

    We consider the electromagnetic production of positron in collision of slow heavy nuclei, with the simultaneously produced electron captured by one of the nuclei. The cross-section of the discussed process exceeds essentially the cross-section of $e^+e^-$ production.

  8. RFP for the Comet Nuclei Tour (CONTOUR)

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Madsen, Peter Buch; Betto, Maurizio

    1999-01-01

    This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program.......This document describes the ASC Star Tracker (performance, functionality, requirements etc.) to The Johns Hopkins University - Applied Physics Laboratory for their Comet Nuclei TOUR (CONTOUR) Program....

  9. Towards the exact calculation of medium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gandolfi, Stefano [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlson, Joseph Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lonardoni, Diego [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Xiaobao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-19

    The prediction of the structure of light and medium nuclei is crucial to test our knowledge of nuclear interactions. The calculation of the nuclei from two- and three-nucleon interactions obtained from rst principle is, however, one of the most challenging problems for many-body nuclear physics.

  10. Variation of hadron masses in finite nuclei

    CERN Document Server

    Saitô, K; Tsushima, K; Saito, Koichi; Thomas, Anthony W.; Tsushima, Kazuo

    1997-01-01

    Using a self-consistent, Hartree description for both infinite nuclear matter and finite nuclei based on a relativistic quark model (the quark-meson coupling model), we investigate the variation of the masses of the non-strange vector mesons, the hyperons and the nucleon in infinite nuclear matter and in finite nuclei.

  11. Energy Radiation of the Active Galactic Nuclei

    Institute of Scientific and Technical Information of China (English)

    TANG Zhi-Ming; WANG Yong-Jiu

    2004-01-01

    In the Hellings-Nordtvedt theory, we obtain some expressions of energy radiation and mass defect effect for a kind of the active galactic nuclei, which is meaningful to calculating the energy radiation in the procession of forming this kind of celestial bodies. This calculation can give some interpretation for energy source of the jet from the active galactic nuclei.

  12. Mean-field models and exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K. [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany)]|[Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P.G. [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)

    1998-06-01

    We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

  13. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUO Wen-Jun; JIANG Huan-Qing; LIU Jian-Ye; ZUO Wei; REN Zhong-Zhou; LEE Xi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable. nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy. The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite different mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  14. Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei

    Institute of Scientific and Technical Information of China (English)

    GUOWen-Jun; JIANGHuan-Qing; LIUJian-Ye; ZUOWei; RENZhong-Zhou; LEEXi-Guo

    2003-01-01

    We develop a method for calculation of the total reaction cross sections induced by the halo nuclei and stable nuclei. This approach is based on the Glauber theory, which is valid for nuclear reactions at high energies. It is extended for nuclear reactions at low energies and intermediate energies by including both the quantum correction and Coulomb correction under the assumption of the effective nuclear density distribution. The calculated results of the total reaction cross section induced by stable nuclei agree well with 30 experimental data within 10 percent accuracy.The comparison between the numerical results and 20 experimental data for the total nuclear reaction cross section induced by the neutron halo nuclei and the proton halo nuclei indicates a satisfactory agreement after considering the halo structure of these nuclei, which implies quite digerent mean fields for the nuclear reactions induced by halo nuclei and stable nuclei. The halo nucleon distributions and the root-mean-square radii of these nuclei can be extracted from the above comparison based on the improved Glauber model, which indicates clearly the halo structures of these nuclei. Especially,it is clear to see that the medium correction of the nucleon-nucleon collision has little effect on the total reaction cross sections, induced by the halo nuclei due to the very weak binding and the very extended density distribution.

  15. Fusion probability in heavy nuclei

    Science.gov (United States)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2015-03-01

    Background: Fusion between two massive nuclei is a very complex process and is characterized by three stages: (a) capture inside the potential barrier, (b) formation of an equilibrated compound nucleus (CN), and (c) statistical decay of the CN leading to a cold evaporation residue (ER) or fission. The second stage is the least understood of the three and is the most crucial in predicting yield of superheavy elements (SHE) formed in complete fusion reactions. Purpose: A systematic study of average fusion probability, PCN> , is undertaken to obtain a better understanding of its dependence on various reaction parameters. The study may also help to clearly demarcate onset of non-CN fission (NCNF), which causes fusion probability, PCN, to deviate from unity. Method: ER excitation functions for 52 reactions leading to CN in the mass region 170-220, which are available in the literature, have been compared with statistical model (SM) calculations. Capture cross sections have been obtained from a coupled-channels code. In the SM, shell corrections in both the level density and the fission barrier have been included. PCN> for these reactions has been extracted by comparing experimental and theoretical ER excitation functions in the energy range ˜5 %-35% above the potential barrier, where known effects of nuclear structure are insignificant. Results: PCN> has been shown to vary with entrance channel mass asymmetry, η (or charge product, ZpZt ), as well as with fissility of the CN, χCN. No parameter has been found to be adequate as a single scaling variable to determine PCN> . Approximate boundaries have been obtained from where PCN> starts deviating from unity. Conclusions: This study quite clearly reveals the limits of applicability of the SM in interpreting experimental observables from fusion reactions involving two massive nuclei. Deviation of PCN> from unity marks the beginning of the domain of dynamical models of fusion. Availability of precise ER cross sections

  16. Chemical complexity in galactic nuclei

    Science.gov (United States)

    Martin-Pintado, Jesus

    2007-12-01

    In recent years our knowledge of the chemical complexity in the nuclei of galaxies has dramatically changed. Recent observations of the nucleus of the Milky Way, of the starburst galaxy NGC253 and of the ultraluminous infrared galaxy (ULIRG) Arp220 have shown large abundance of complex organic molecules believed to be formed on grains. The Galactic center appears to be the largest repository of complex organic molecule like aldehydes and alcohols in the galaxy. We also measure large abundance of methanol in starburst galaxies and in ULIRGs suggesting that complex organic molecules are also efficiently produced in the central region of galaxies with strong star formation activity. From the systematic observational studies of molecular abundance in regions dominated by different heating processes like shocks, UV radiation, X-rays and cosmic rays in the center of the Milky Way, we are opening the possibility of using chemistry as a diagnostic tool to study the highly obscured regions of galactic centers. The templates found in the nucleus of the Milky Way will be used to establish the main mechanisms driving the heating and the chemistry of the molecular clouds in galaxies with different type of activity. The role of grain chemistry in the chemical complexity observed in the center of galaxies will be also briefly discussed.

  17. Molecular outflows in starburst nuclei

    CERN Document Server

    Roy, Arpita; Sharma, Prateek; Shchekinov, Yuri

    2016-01-01

    Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with $N_{OB}\\ge 10^5$ (corresponding to a star formation rate (SFR)$\\ge 1$ M$_{\\odot}$ yr$^{-1}$ in the nuclear region), in a stratified disk with mid-plane density $n_0\\sim 200\\hbox{--}1000$ cm$^{-3}$ and scale height $z_0\\ge 200 (n_0/10^2 \\, {\\rm cm}^{-3})^{-3/5}$ pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is $\\ge 10^7$ M$_\\odot$ at a distance of a few hundred pc, with a speed of several tens of km s$^{-1}$. We show that a SFR surface density of $10 \\le \\Sigma_{SFR} \\le 50$ M$_\\odot$ yr$^{-1}$ kpc$^{-2}$ favours the production of molecular outflows, consistent with observed values.

  18. The morphology of cometary nuclei

    Science.gov (United States)

    Keller, H. U.; Jorda, L.

    comets display residual activity or clouds of dust grains around their nuclei. Taking the residual signal into account (mostly using simple models for the brightness distribution) the size estimates of the nuclei could be improved. The (nuclear) magnitude of a comet depends on the product of its albedo and cross-section. Only in a few cases could the albedo and size of a cometary nucleus be separated by additional observation of its thermal emission at infrared wavelengths. By comparison with outer Solar System asteroids Cruikshank et al. (1985) derived a surprisingly low albedo of about 0.04. A value in clear contradiction to the perception of an icy surface but fully confirmed by the first resolved images of a cometary nucleus during the flybys of the Vega and Giotto spacecraft of comet Halley (Sagdeev et al. 1986, Keller et al. 1986). The improvements of radar techniques led to the detection of reflected signals and finally to the derivation of nuclear dimensions and rotation rates. The observations, however, are also model dependent (rotation and size are similarly interwoven as are albedo and size) and sensitive to large dust grains in the vicinity of a nucleus. As an example, Kamoun et al. (1982) determined the radius of comet Encke to 1.5 (2.3, 1.0) km using the spin axis determination of Whipple and Sekanina (1979). The superb spatial resolution of the Hubble Space Telescope (HST) is not quite sufficient to resolve a cometary nucleus. The intensity distribution of the inner coma, however, can be observed and extrapolated toward the nucleus based on models of the dust distribution. If this contribution is subtracted from the central brightness the signal of the nucleus can be derived and hence its product of albedo times cross-section (Lamy and Toth 1995, Rembor 1998, Keller and Rembor 1998; Section 4.3). It has become clear that cometary nuclei are dark, small, often irregular bodies with dimensions ranging from about a kilometre (comet Wirtanen, the target of

  19. Alpha decay chains from superheavy nuclei

    CERN Document Server

    Samanta, C

    2008-01-01

    Magic islands for extra-stable nuclei in the midst of the sea of fission-instability were predicted to be around Z=114, 124 or, 126 with N=184, and Z=120, with N=172. Whether these fission-survived superheavy nuclei with high Z and N would live long enough for detection or, undergo alpha-decay in a very short time remains an open question. Alpha-decay half lives of nuclei with 130 118 are found to have alpha-decay half lives of the order of microseconds or, less.

  20. Deep inelastic scattering on asymmetric nuclei

    Science.gov (United States)

    Saito, K.; Boros, C.; Tsushima, K.; Bissey, F.; Afnan, I. R.; Thomas, A. W.

    2000-11-01

    We study deep inelastic scattering on isospin asymmetric nuclei. In particular, the difference of the nuclear structure functions and the Gottfried sum rule for the lightest mirror nuclei, 3He and 3H, are investigated. It is found that such systems can provide significant information on charge symmetry breaking and flavor asymmetry in the nuclear medium. Furthermore, we propose a new method to extract the neutron structure function from radioactive isotopes far from the line of stability. We also discuss the flavor asymmetry in the Drell-Yan process with isospin asymmetric nuclei.

  1. Coupled-cluster computations of atomic nuclei

    CERN Document Server

    Hagen, G; Hjorth-Jensen, M; Dean, D J

    2013-01-01

    In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.

  2. HATS-9b AND HATS-10b: TWO COMPACT HOT JUPITERS IN FIELD 7 OF THE K2 MISSION

    CERN Document Server

    Brahm, R; Hartman, J D; Bakos, G Á; Bayliss, D; Penev, K; Zhou, G; Ciceri, S; Rabus, M; Espinoza, N; Mancini, L; de Val-Borro, M; Bhatti, W; Sato, B; Tan, T G; Csubry, Z; Buchhave, L; Henning, T; Schmidt, B; Suc, V; Noyes, R W; Papp, I; Lázár, J; Sári, P

    2015-01-01

    We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 $\\pm$ 1.5 Gyr) V=13.3 G dwarf star, with a period P = 1.9153 d. The host star has a mass of 1.03 M$_{\\odot}$, radius of 1.503 R$_\\odot$ and effective temperature 5366 $\\pm$ 70 K. The planetary companion has a mass of 0.837 M$_J$, and radius of 1.065 R$_J$ yielding a mean density of 0.85 g cm$^{-3}$ . HATS-10b orbits a V=13.1 G dwarf star, with a period P = 3.3128 d. The host star has a mass of 1.1 M$_\\odot$, radius of 1.11 R$_\\odot$ and effective temperature 5880 $\\pm$ 120 K. The planetary companion has a mass of 0.53 M$_J$, and radius of 0.97 R$_J$ yielding a mean density of 0.7 g cm$^{-3}$ . Both planets are compact in comparison with planets receiving similar irradiation from their host stars, and lie in the nominal coordinates of Field 7 of K2 but only HATS-9b falls on working silicon. Future characterisation of HATS-9b with the exquisite photometric precision of the Kepler telescope may provid...

  3. A Bayesian Atmospheric Retrieval Performed on HAT-P-16b and WASP-11b/HAT-P-10b

    Science.gov (United States)

    McIntyre, Kathleen J.; Harrington, Joseph; Challener, Ryan C.; Hardin, Matthew Ryan; Bowman, Oliver Oliver; Foster, Andrew S. D.; Lenius, Maria; Hartman, Joel D.; Bakos, Gaspar; Blecic, Jasmina; Cubillos, Patricio; Ariston Hardy, Ryan; Cameron, Andrew

    2016-10-01

    HAT-P-16b is a hot (equilibrium temperature 1626 ± 40 K, assuming zero Bond albedo and efficient energy redistribution), 4.19 ± 0.09 Jupiter-mass exoplanet orbiting an F8 star every 2.775960 ± 0.000003 days (Buchhave et al 2010). WASP-11b/HAT-P-10b is a cooler (1020 ± 17 K), 0.487 ± 0.018 Jupiter-mass exoplanet orbiting a K3 star every 3.7224747 ± 0.0000065 days (Bakos et al. 2009, co-discovered by West et al. 2008). We observed secondary eclipses of both planets using the 3.6 μm and 4.5 μm channels of the Spitzer Space Telescope's Infrared Array Camera (program ID 60003). We applied our Bayesian Atmospheric Radiative Transfer (BART) code to constrain the temperature-pressure profiles and atmospheric molecular abundances of the two planets. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.

  4. Critical-Point Structure in Finite Nuclei

    CERN Document Server

    Leviatan, A

    2006-01-01

    Properties of quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Special emphasis is paid to the dynamics at the critical-point of a general first-order phase transition.

  5. Few-Body Universality in Halo Nuclei

    Directory of Open Access Journals (Sweden)

    Hammer H.-W.

    2016-01-01

    Full Text Available Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.

  6. Few-Body Universality in Halo Nuclei

    Science.gov (United States)

    Hammer, H.-W.

    2016-03-01

    Few-body systems with resonant S-wave interactions show universal properties which are independent of the interaction at short distances. These properties include a geometric spectrum of three- and higher-body bound states and universal correlations between few-body observables. They can be observed on a wide range of scales from hadrons and nuclei to ultracold atoms. In this contribution, we focus on few-body universality in halo nuclei which can be considered as effective few-body systems consisting of halo nucleons and a core. This concept provides a unifying framework for halo nuclei with calculable corrections. Recent progress in this field with an emphasis on the possibility of finding Efimov states in halo nuclei is discussed.

  7. GDR in Hot Nuclei: New Measurements

    Science.gov (United States)

    Camera, F.; Kmiecik, M.; Wieland, O.; Benzoni, G.; Bracco, A.; Brambilla, S.; Crespi, F.; Mason, P.; Moroni, A.; Million, B.; Leoni, S.; Maj, A.; Styczen, J.; Brekiesz, M.; Meczynski, W.; Zieblinski, M.; Gramegna, F.; Barlini, S.; Kravchuk, V. L.; Lanchais, A. L.; Mastinu, P. F.; Bruno, M.; D'Agostino, M.; Geraci, E.; Ordine, A.; Casini, G.; Chiari, M.

    2005-04-01

    The measured properties of the Giant Dipole Resonance in hot rotating nuclei are successfully described with the model of thermal fluctuations, even though there are still some open problems especially at very low (T 2.5MeV) temperatures and missing data in some mass regions. Recent experimental works have addressed more specific problems regarding the nuclear shape and its behaviour in very particular and delimited phase space regions. In this paper will be discussed new exclusive measurements of the GDR γ decay in heavy 216Rn nuclei (where the shape of nuclei surviving fission have been probed) and some preliminary data on the 132Ce nuclei at very high excitation energy.

  8. Quantum Monte Carlo Calculations of Light Nuclei

    CERN Document Server

    Pieper, Steven C

    2007-01-01

    During the last 15 years, there has been much progress in defining the nuclear Hamiltonian and applying quantum Monte Carlo methods to the calculation of light nuclei. I describe both aspects of this work and some recent results.

  9. On The Structure of A=3 Nuclei

    CERN Document Server

    Abbas, Syed Afsar

    2011-01-01

    The hole in the charge distribution of $^3{\\text He}$ is a major problem in A=3 nuclei. The canonical wavefucntion of A=3 nuclei which does well for electromagnetic properties of A=3 nuclei fails to produce the hole in A=3 nuclei. The hole is normally assumed to arise from explicit quark degree of freedom. Very often quark degrees of freedom are imposed to propose a different short range part of the wavefunction for A=3 to explain the hole in $^3{\\text He}$. So an hybrid model with nucleonic degree of freedom in outer part and quark degrees of freedom in the inner part of the nucleus have been invoked to understand the above problem. Here we present a different picture with a new wavefunction working at short range within nucleonic degrees of freedom itself. So the above problem is explained here based entirely on the nucleonic degree of freedom only.

  10. Synthesis of superheavy nuclei: Obstacles and opportunities

    Directory of Open Access Journals (Sweden)

    Zagrebaev V.I.

    2015-01-01

    Full Text Available There are only 3 methods for the production of heavy and superheavy (SH nuclei, namely, fusion reactions, a sequence of neutron capture and beta(- decay and multinucleon transfer reactions. Low values of the fusion cross sections and very short half-lives of nuclei with Z<120 put obstacles in synthesis of new elements. At the same time, an important area of SH isotopes located between those produced in the cold and hot fusion reactions remains unstudied yet. This gap could be filled in fusion reactions of 48Ca with available lighter isotopes of Pu, Am, and Cm. New neutron-enriched isotopes of SH elements may be produced with the use of a 48Ca beam if a 250Cm target would be prepared. In this case we get a real chance to reach the island of stability owing to a possible beta(+ decay of 291114 and 287112 nuclei formed in this reaction with a cross section of about 0.8 pb. A macroscopic amount of the long-living SH nuclei located at the island of stability may be produced by using the pulsed nuclear reactors of the next generation only if the neutron fluence per pulse will be increased by about three orders of magnitude. Multinucleon transfer processes look quite promising for the production and study of neutron-rich heavy nuclei located in upper part of the nuclear map not reachable by other reaction mechanisms. Reactions with actinide beams and targets are of special interest for synthesis of new neutron-enriched transfermium nuclei and not-yet-known nuclei with closed neutron shell N=126 having the largest impact on the astrophysical r-process. The estimated cross sections for the production of these nuclei allows one to plan such experiments at currently available accelerators.

  11. E1 strength in N = 82 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, T.; Volz, S.; Babilon, M.; Mohr, P.; Vogt, K.; Zilges, A

    2003-05-19

    Recently the importance of small contributions of electric dipole strength near the particle threshold to the production rates of atomic nuclei has become evident. Prior estimates concentrated on the Giant Dipole Resonance (GDR) which dominates photoabsorption in all nuclei. Extrapolations to smaller excitation energies were assumed to be sufficiently reliable. However, new measurements reveal that collective E1 strength can be found in the threshold region.

  12. Statistical Properties of Quantum Spectra in Nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behaviors of quantum spectrum in nuclei. The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei. The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described. The influence of pairing effect on the order to chaos transition is also discussed. Some important experiment phenomena in nuclear

  13. Shell structure of nuclei far from stability

    CERN Document Server

    Grawe, H

    2001-01-01

    The experimental status of shell structure studies in medium-heavy nuclei far off the line of beta-stability is reviewed. Experimental techniques, signatures for shell closure and expectations for future investigations are discussed for the key regions around sup 4 sup 8 sup , sup 5 sup 6 Ni, sup 1 sup 0 sup 0 Sn for proton rich nuclei and the neutron-rich N=20 isotones, Ca, Ni and Sn isotopes.

  14. Masses of nuclei close to the dripline

    CERN Document Server

    Herfurth, F; Beck, D; Blaum, K; Bollen, G; Kellerbauer, A G; Kluge, H J; Lunney, M D; Rodríguez, D; Schwarz, S; Sikler, G; Weber, C

    2003-01-01

    Mass measurements of radioactive nuclides are one of the cornerstones of our understanding of the nucleus. The Penning trap spectrometer ISOLTRAP performs direct mass measurements far away from the valley of stability, as well as high-precision measurements of key nuclei to anchor long decay chains. Both schemes provide valuable information on the dripline itself and on nuclei in its close vicinity. (10 refs) .

  15. Realistic level density calculation for heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Cerf, N. [Institut de Physique Nucleaire, Orsay (France); Pichon, B. [Observatoire de Paris, Meudon (France); Rayet, M.; Arnould, M. [Institut d`Astronomie et d`Astrophysique, Bruxelles (Belgium)

    1994-12-31

    A microscopic calculation of the level density is performed, based on a combinatorial evaluation using a realistic single-particle level scheme. This calculation relies on a fast Monte Carlo algorithm, allowing to consider heavy nuclei (i.e., large shell model spaces) which could not be treated previously in combinatorial approaches. An exhaustive comparison of the predicted neutron s-wave resonance spacings with experimental data for a wide range of nuclei is presented.

  16. Quark Degrees of Freedom in Finite Nuclei

    CERN Document Server

    Tsushima, K; Thomas, A W; Tsushima, Kazuo; Saito, Koichi; Thomas, Anthony W.

    1996-01-01

    Properties of finite nuclei are investigated based on relativistic Hartree equations which have been derived from a relativistic quark model of the structure of bound nucleons. Nucleons are assumed to interact through the (self-consistent) exchange of scalar ($\\sigma$) and vector ($\\omega$ and and the rms charge radius in $^{40}$Ca. Calculated properties of static, closed-shell nuclei, as well as symmetric nuclear matter are compared with experimental data and with the results of Quantum Hadrodynamics (QHD).

  17. Radiation portal monitor with {sup 10}B+ZnS(Ag) neutron detector performance for the detection of special nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Guzman G, K. A.; Gallego, E.; Lorente, A.; Ibanez F, S. [Universidad Politecnica de Madrid, Departamento de Ingenieria Energetica, ETSI Industriales, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Gonzalez, J. A. [Universidad Politecnica de Madrid, Laboratorio de Ingenieria Nuclear, ETSI Caminos, Canales y Puertos, C. Prof. Aranguren 3, 28040 Madrid (Spain); Mendez, R., E-mail: ingkarenguzman@gmail.com [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 40, 28040 Madrid (Spain)

    2016-10-15

    In homeland security, neutron detection is used to prevent the smuggling of special nuclear materials. Thermal neutrons are normally detected with {sup 3}He proportional counters, in the radiation portal monitors, Rpms, however due to the {sup 3}He shortage new procedures are being studied. In this work Monte Carlo methods, using the MCNP6 code, have been used to study the neutron detection features of a {sup 10}B+ZnS(Ag) under real conditions inside of a Rpm. The performance for neutron detection was carried out for {sup 252}Cf, {sup 238}U and {sup 239}Pu under different conditions. In order to mimic an actual situation occurring at border areas, a sample of SNM sited inside a vehicle was simulated and the Rpm with {sup 10}B+ZnS(Ag) response was calculated. At 200 cm the {sup 10}B+ZnS(Ag) on Rpm response is close to 2.5 cps-ng {sup 252}Cf, when the {sup 252}Cf neutron source is shielded with 0.5 cm-thick lead and 2.5 cm-thick polyethylene fulfilling the ANSI recommendations. Three different geometries of neutron detectors of {sup 10}B+ZnS(Ag) in a neutron detection system in Rpm were modeled. Therefore, the {sup 10}B+ZnS(Ag) detectors are an innovative and viable replacement for the {sup 3}He detectors in the Rpm. (Author)

  18. Polymer nanoparticles mediated codelivery of antimiR-10b and antimiR-21 for achieving triple negative breast cancer therapy.

    Science.gov (United States)

    Devulapally, Rammohan; Sekar, Narayana M; Sekar, Thillai V; Foygel, Kira; Massoud, Tarik F; Willmann, Jürgen K; Paulmurugan, Ramasamy

    2015-03-24

    The current study shows the therapeutic outcome achieved in triple negative breast cancer (TNBC) by simultaneously antagonizing miR-21-induced antiapoptosis and miR-10b-induced metastasis, using antisense-miR-21-PS and antisense-miR-10b-PS delivered by polymer nanoparticles (NPs). We synthesized the antisense-miR-21 and antisense-miR-10b loaded PLGA-b-PEG polymer NPs and evaluated their cellular uptake, serum stability, release profile, and the subsequent synchronous blocking of endogenous miR-21 and miR-10b function in TNBC cells in culture, and tumor xenografts in living animals using molecular imaging. Results show that multitarget antagonization of endogenous miRNAs could be an efficient strategy for targeting metastasis and antiapoptosis in the treatment of metastatic cancer. Targeted delivery of antisense-miR-21 and antisense-miR-10b coloaded urokinase plasminogen activator receptor (uPAR) targeted polymer NPs treated mice showed substantial reduction in tumor growth at very low dose of 0.15 mg/kg, compared to the control NPs treated mice and 40% reduction in tumor growth compared to scramble peptide conjugated NPs treated mice, thus demonstrating a potential new therapeutic option for TNBC.

  19. Effect of time period after boric acid injection on {sup 10}B absorption in different regions of adult male rat's brain

    Energy Technology Data Exchange (ETDEWEB)

    Baghban Khojasteh, Nasrin, E-mail: khojasteh.nasrin@gmail.com [Nuclear Engineering Department, Science and Research Branch, Islamic Azad University, Poonak Sq. PO Box 14515-775, Tehran (Iran, Islamic Republic of); Pazirandeh, Ali [Nuclear Engineering Department, Science and Research Branch, Islamic Azad University, Poonak Sq. PO Box 14515-775, Tehran (Iran, Islamic Republic of); Jameie, Behnam [Nuclear Engineering Department, Science and Research Branch, Islamic Azad University, Poonak Sq. PO Box 14515-775, Tehran (Iran, Islamic Republic of); Laboratory of Basic Science and Neuroscience, Basic Science Dept, Faculty of Allied Medicine, Cellular and Molecular Research Center, Tehran University of Medical Science, Pardis-e-Hemmat,Tehran (Iran, Islamic Republic of); Goodarzi, Samereh [Nuclear Engineering Department, Science and Research Branch, Islamic Azad University, Poonak Sq. PO Box 14515-775, Tehran (Iran, Islamic Republic of)

    2012-06-15

    Distribution of {sup 10}B in different regions of rat normal brain was studied. Two groups were chosen as control and trial. Trial group received 2 ml of neutral boron compound. 2, 4 and 6 h after the injection brain removed, coronal sections of forebrain, midbrain and hindbrain were sandwiched between two pieces of polycarbonate. Autoradiography plots of {sup 10}B distribution showed significant differences in three regions with the highest {sup 10}B concentration in the forebrain during 4 h after injection. - Highlights: Black-Right-Pointing-Pointer Normal tissue tolerance is very important in BNCT. Black-Right-Pointing-Pointer This study has been done to determine {sup 10}B distribution in three anatomical regions of rat normal brain. Black-Right-Pointing-Pointer These specific regions of brain have not been studied in previous BNCT projects. Black-Right-Pointing-Pointer We found significant differences in {sup 10}B distribution between these three regions. Black-Right-Pointing-Pointer In different time periods after neutral boron compound injection, there has been a significant difference in boron absorption.

  20. The observation of charge exchange of pions captured in several nuclei

    Science.gov (United States)

    Bassalleck, B.; Corriveau, F.; Hasinoff, M. D.; Marks, T.; Measday, D. F.; Poutissou, J.-M.; Salomon, M.

    1981-06-01

    We have measured for the first time the branching ratios of the charge exchange of stopped negative pions in targets of 6Li, Al, Ti, Cu, Nb and Pb. These branching ratios are of the order of 10 -6, about an order of magnitude smaller than the upper limit previously established. Using the branching ratio for radiative pion capture in 6Li to the ground state of 6He we obtain the Panofsky ratio in 6Li, P6 = (8.7 ± 2.3) × 10 -4.

  1. Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua, E-mail: hrh20022002@163.com

    2016-04-30

    Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

  2. Electron scattering and reactions from exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Karataglidis, S. [University of Johannesburg, Department of Physics, Auckland Park (South Africa); University of Melbourne, School of Physics, Victoria (Australia)

    2017-04-15

    The SCRIT and FAIR/ELISe experiments are the first to attempt to measure directly electron scattering form factors from nuclei far from stability. This will give direct information for the (one-body) charge densities of those systems, about which there is little information available. The SCRIT experiment will be taking data for medium-mass exotic nuclei, while the electron-ion collider at ELISe, when constructed, will be able to measure form factors for a wide range of exotic nuclei, as available from the radioactive ion beams produced by the FAIR experiment. Other facilities are now being proposed, which will also consider electron scattering from exotic nuclei at higher energies, to study short-range correlations in exclusive reactions. This review will consider all available information concerning the current status (largely theoretical) of electron scattering from exotic nuclei and, where possible, complement such information with equivalent information concerning the neutron densities of those exotic systems, as obtained from intermediate energy proton scattering. The issue of long- and short-range correlations will be discussed, and whether extending such studies to the exotic sector will elicit new information. (orig.)

  3. Pollen grains are efficient cloud condensation nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pope, F D, E-mail: fdp21@cam.ac.uk [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2010-10-15

    This letter presents a laboratory study investigating the ability of pollen grains to act as cloud condensation nuclei. The hygroscopicity of pollen is measured under subsaturated relative humidities using an electrodynamic balance. It is found, along with other results, that pollen exhibits bulk uptake of water under subsaturated conditions. Through the use of an environmental scanning electron microscope it was observed that the surface of pollen is wettable at high subsaturated humidities. The hygroscopic response of the pollen to subsaturated relative humidities is parametrized using {kappa}-Koehler theory and values of the parameter {kappa} for pollen are between 0.05 and 0.1. It is found that while pollen grains are only moderately hygroscopic, they can activate at critical supersaturations of 0.001% and lower, and thus pollen grains will readily act as cloud condensation nuclei. While the number density of pollen grains is too low for them to represent a significant global source of cloud condensation nuclei, the large sizes of pollen grains suggest that they will be an important source of giant cloud condensation nuclei. Low temperature work using the environmental scanning electron microscope indicated that pollen grains do not act as deposition ice nuclei at temperatures warmer than - 15 deg. C.

  4. T10B9 monoclonal antibody: A short-acting nonstimulating monoclonal antibody that spares γδ T-cells and treats and prevents cellular rejection

    Directory of Open Access Journals (Sweden)

    Thomas H Waid

    2009-06-01

    Full Text Available Thomas H Waid1, John S Thompson1, Maria Siemionow2, Stephen A Brown1 1Department of Internal Medicine, University of Kentucky, Lexington, Kentucky, USA; 2Cleveland Clinic, Cleveland, Ohio, USAAbstract: T10B9.1A-31/MEDI-500 is a nonmitogenic immunoglobulin M kappa murine monoclonal antibody (mAb directed against the alpha-beta (αβ heterodimer of the T-lymphocyte receptor complex. The hybridoma was first produced by fusing spleen cells from BALB/C mice immunized with human peripheral blood T-lymphocytes with SP2/O-Ag14 mutant myeloma cells. The mAb is produced and purified using multistep ion exchange and molecular sieve chromatography protocols. T10B9 has been used successfully to treat acute cellular rejection in renal transplantation and as an immunosuppression induction agent in heart and simultaneous kidney-pancreas transplantation. Because T10B9 is nonmitogenic and causes minimal cytokine release, both treatment of rejection and induction of immunosuppression were accomplished with significantly fewer and milder untoward effects (cytokine release syndrome than its comparator OKT3. Since T10B9 is directed against the αβ heterodimer of the CD3 epitope, it spares the gamma delta (γδ region. These gamma delta (γδ T cells have a unique role in the immune response controlling many serious human diseases and perhaps facilitating the development of immunologic tolerance. T10B9 has a relatively short duration of action, depleting T cells for only 10 to 14 days, unlike the protracted depletion seen with thymoglobulin and Campath-1H. There is no B-lymphocyte depletion with T10B9 as there is with both of the aforementioned reagents. The lack of prolonged lymphocyte depletion may account for less infection observed with T10B9 treatment.Keywords: T10B9.1A-31, γδ T-cell, monoclonal antibody, Campath-1H, thymoglobulin, OKT3

  5. The Scattering of Fast Nucleons from Nuclei

    Science.gov (United States)

    Kerman, A. K.; McManus, H.; Thaler, R. M.

    2000-04-01

    The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon-nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above ˜100 Mev appears to be consistent with the theory.

  6. The scattering of fast nucleons from nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kerman, A. K. [Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); McManus, H. [Chalk River Laboratory, Chalk River, Ontario, (Canada); Thaler, R. M. [Los Alamos Scientific Laboratory, Los Alamos, New Mexico (United States)

    2000-04-10

    The formal theory of the scattering of high-energy nucleons by nuclei is developed in terms of the nucleon nucleon scattering amplitude. The most important approximations necessary to make numerical calculation feasible are then examined. The optical model potential is derived on this basis and compared with the optical model parameters found from experiment. The elastic scattering and polarization of nucleons from light nuclei is predicted and compared with experiment. The effect of nuclear correlations is discussed. The polarization of inelastically scattered nucleons is discussed and predictions compared with experiments. To within the validity of the approximations the experimental data on the scattering of nucleons from nuclei at energies above {approx}100 Mev appears to be consistent with the theory. (c) 2000 Academic Press, Inc.

  7. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... on the surface of particles and bounding walls. Such nuclei can be related to the full range of tensile strengths measured, when differences of experimental conditions are taken into consideration. The absence or presence of contamination on surfaces, as well as the structure of the surfaces, are central...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...

  8. Nucleon localization in light and heavy nuclei

    CERN Document Server

    Zhang, C L; Nazarewicz, W

    2016-01-01

    An electron localization measure was originally introduced to characterize chemical bond structures in molecules. Recently, a nucleon localization based on Hartree-Fock densities has been introduced to investigate $\\alpha$-cluster structures in light nuclei. Compared to the local nucleonic densities, the nucleon localization function has been shown to be an excellent indicator of shell effects and cluster correlations. Using the spatial nucleon localization measure, we investigate the cluster structures in deformed light nuclei and study the emergence of fragments in fissioning heavy nuclei. To illustrate basic concepts of nucleon localization, we employ the deformed harmonic oscillator model. Realistic calculations are carried out using self-consistent nuclear density functional theory with quantified energy density functionals optimized for fission studies. We study particle densities and spatial nucleon localization distributions for deformed cluster configurations of $^{8}$Be and $^{20}$Ne, and also along...

  9. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...... pressure, the possibility of stabilization of free gas bubbles by a skin has been documented, but only within a range of bubble sizes that makes them responsible for tensile strengths up to about 1.5 bar, and values reaching almost 300 bar have been measured. However, cavitation nuclei can also be harbored...

  10. Alpha-cluster model of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sosin, Zbigniew; Kallunkathariyil, Jinesh [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland); Blocki, Jan [NCBJ, Theoretical Physics Division (BP2), Swierk (Poland); Lukasik, Jerzy; Pawlowski, Piotr [IFJ PAN, Krakow (Poland)

    2016-05-15

    The description of a nuclear system in its ground state and at low excitations based on the equation of state (EoS) around normal density is presented. In the expansion of the EoS around the saturation point, additional spin polarization terms are taken into account. These terms, together with the standard symmetry term, are responsible for the appearance of the α-like clusters in the ground-state configurations of the N=Z even-even nuclei. At the nuclear surface these clusters can be identified as alpha particles. A correction for the surface effects is introduced for atomic nuclei. Taking into account an additional interaction between clusters the binding energies and sizes of the considered nuclei are very accurately described. The limits of the EoS parameters are established from the properties of the α, {sup 3}He and t particles. (orig.)

  11. Shape phase mixing in critical point nuclei

    CERN Document Server

    Budaca, R

    2016-01-01

    Spectral properties of nuclei near the critical point of the quantum phase transition between spherical and axially symmetric shapes are studied in a hybrid collective model which combines the $\\gamma$-stable and $\\gamma$-rigid collective conditions through a rigidity parameter. The model in the lower and upper limits of the rigidity parameter recovers the X(5) and X(3) solutions respectively, while in the equally mixed case it corresponds to the X(4) critical point symmetry. Numerical applications of the model on nuclei from regions known for critical behavior reveal a sizable shape phase mixing and its evolution with neutron or proton numbers. The model also enables a better description of energy spectra and electromagnetic transitions for these nuclei.

  12. Statistical ensembles and fragmentation of finite nuclei

    Science.gov (United States)

    Das, P.; Mallik, S.; Chaudhuri, G.

    2017-09-01

    Statistical models based on different ensembles are very commonly used to describe the nuclear multifragmentation reaction in heavy ion collisions at intermediate energies. Canonical model results are more appropriate for finite nuclei calculations while those obtained from the grand canonical ones are more easily calculable. A transformation relation has been worked out for converting results of finite nuclei from grand canonical to canonical and vice versa. The formula shows that, irrespective of the particle number fluctuation in the grand canonical ensemble, exact canonical results can be recovered for observables varying linearly or quadratically with the number of particles. This result is of great significance since the baryon and charge conservation constraints can make the exact canonical calculations extremely difficult in general. This concept developed in this work can be extended in future for transformation to ensembles where analytical solutions do not exist. The applicability of certain equations (isoscaling, etc.) in the regime of finite nuclei can also be tested using this transformation relation.

  13. Monte Carlo approaches to light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.

    1990-01-01

    Significant progress has been made recently in the application of Monte Carlo methods to the study of light nuclei. We review new Green's function Monte Carlo results for the alpha particle, Variational Monte Carlo studies of {sup 16}O, and methods for low-energy scattering and transitions. Through these calculations, a coherent picture of the structure and electromagnetic properties of light nuclei has arisen. In particular, we examine the effect of the three-nucleon interaction and the importance of exchange currents in a variety of experimentally measured properties, including form factors and capture cross sections. 29 refs., 7 figs.

  14. Statistical properties of quantum spectra in nuclei

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some aspects of quantum chaos in a finite system have been studied based on the analysis of statistical behavior of quantum spectra in nuclei.The experiment data show the transition from order to chaos with increasing excitation energy in spherical nuclei.The dependence of the order to chaos transition on nuclear deformation and nuclear rotating is described.The influence of pairing effect on the order to chaos transition is also discussed.Some important experiment phenomena in nuclear physics have been understood from the point of view of the interplay between order and chaos.

  15. Doubly magic properties in superheavy nuclei

    Institute of Scientific and Technical Information of China (English)

    HUANG Ya-Wei; ZHU Jian-Yu

    2009-01-01

    A systematic study of global properties of superheavy nuclei in the framework of the Liquid Drop Model and the Strutinsky shell correction method is performed. The evolution equilibrium deformations, TRS graphs and α-decay energies are calculated using the TRS model. The analysis covers a wide range of even-even superheavy nuclei from Z = 102 to 122. Magic numbers and their observable influence occurring in this region have been investigated. Shell closures appear at proton number Z = 114 and at neutron number N = 184.

  16. Computer Model Of Fragmentation Of Atomic Nuclei

    Science.gov (United States)

    Wilson, John W.; Townsend, Lawrence W.; Tripathi, Ram K.; Norbury, John W.; KHAN FERDOUS; Badavi, Francis F.

    1995-01-01

    High Charge and Energy Semiempirical Nuclear Fragmentation Model (HZEFRG1) computer program developed to be computationally efficient, user-friendly, physics-based program for generating data bases on fragmentation of atomic nuclei. Data bases generated used in calculations pertaining to such radiation-transport applications as shielding against radiation in outer space, radiation dosimetry in outer space, cancer therapy in laboratories with beams of heavy ions, and simulation studies for designing detectors for experiments in nuclear physics. Provides cross sections for production of individual elements and isotopes in breakups of high-energy heavy ions by combined nuclear and Coulomb fields of interacting nuclei. Written in ANSI FORTRAN 77.

  17. Medium energy hadron scattering from nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ginocchio, J.N.; Wenes, G.

    1986-01-01

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expresions for the transition matrix elements for the three dynamical symmetries of the interacting boson model; that is for, a spherical quadrupole vibrator, a ..gamma.. unstable rotor, and both prolate and oblate axially symmetric rotors. We give examples of application of this formalism to proton scattering from /sup 154/Sm and /sup 154/Gd. 27 refs., 5 figs., 1 tab.

  18. Light nuclei from chiral EFT interactions

    Science.gov (United States)

    Navrátil, P.; Gueorguiev, V. G.; Vary, J. P.; Ormand, W. E.; Nogga, A.; Quaglioni, S.

    2008-12-01

    Recent developments in nuclear theory allow us to make a connection between quantum chromodynamics (QCD) and low-energy nuclear physics. First, chiral effective field theory (χEFT) provides a natural hierarchy to define two-nucleon ( NN), three-nucleon ( NNN), and even four-nucleon interactions. Second, ab-initio methods have been developed capable to test these interactions for light nuclei. In this contribution, we discuss ab-initio no-core shell-model (NCSM) calculations for s-shell and p-shell nuclei with NN and NNN interactions derived within χEFT.

  19. Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

    Science.gov (United States)

    Yamanaka, Nodoka; Hiyama, Emiko

    2016-02-01

    We calculate for the first time the electric dipole moment (EDM) of the deuteron, 3H, and 3He nuclei generated by the one-meson exchange CP-odd nuclear force in the standard model. The effective |Δ S| = 1 four-quark operators are matched to the |Δ S| = 1 standard model processes involving the CP phase of the Cabibbo-Kobayashi-Maskawa matrix at the electroweak scale and run down to the hadronic scale μ = 1 GeV according to the renormalization group evolution in the next-to-leading logarithmic order. At the hadronic scale, the hadron matrix elements are modeled in the factorization approach. We then obtain the one-meson (pion, eta meson, and kaon) exchange CP-odd nuclear force, which is the combination of the |Δ S| = 1 meson-baryon vertices which issue from the penguin operator and the hyperon-nucleon transition. From this CP-odd nuclear force, the nuclear EDM is calculated with the realistic Argonne v18 interaction and the CP-odd nuclear force using the Gaussian expansion method. It is found that the EDMs of light nuclear systems are of order O (10-31) e cm. We also estimate the standard model contribution to other hadronic CP violating observables such as the EDMs of 6Li, 9Be nuclei, and the atomic EDMs of 129Xe, 199Hg, 211Rn, and 225Ra generated through the nuclear Schiff moment. We then analyze the source of theoretical uncertainties and show some possible ways to overcome them.

  20. Combining miR10b-targeted nanotherapy with low-dose doxorubicin elicits durable regressions of metastatic breast cancer

    Science.gov (United States)

    Yoo, Byunghee; Kavishwar, Amol; Ross, Alana; Wang, Ping; Tabassum, Doris P.; Polyak, Kornelia; Barteneva, Natalia; Petkova, Victoria; Pantazopoulos, Pamela; Tena, Aseda; Moore, Anna; Medarova, Zdravka

    2015-01-01

    The therapeutic promise of microRNA in cancer has yet to be realized. In this study, we identified and therapeutically exploited a new role for miR-10b at the metastatic site, which links its overexpression to tumor cell viability and proliferation. In the protocol developed, we combined a miR-10b-inhibitory nanodrug with low-dose anthracycline to achieve complete durable regressions of metastatic disease in a murine model of metastatic breast cancer. Mechanistic investigations suggested a potent anti-proliferative, pro-apoptotic effect of the nanodrug in the metastatic cells, potentiated by a cell-cycle arrest produced by administration of the low-dose anthracycline. miR-10b was overexpressed specifically in cells with high metastatic potential, suggesting a role for this miRNA as a metastasis-specific therapeutic target. Taken together, our results implied the existence of pathways that regulate the viability and proliferation of tumor cells only after they have acquired the ability to grow at distant metastatic sites. As illustrated by miR-10b targeting, such metastasis-dependent apoptotic pathways would offer attractive targets for further therapeutic exploration. PMID:26359455

  1. Low-level laser treatment stimulates hair growth via upregulating Wnt10b and β-catenin expression in C3H/HeJ mice.

    Science.gov (United States)

    Zhang, Tiran; Liu, Liqiang; Fan, Jincai; Tian, Jia; Gan, Cheng; Yang, Zengjie; Jiao, Hu; Han, Bing; Liu, Zheng

    2017-07-01

    This study was conducted in order to evaluate the role of low-level laser treatment (LLLT) in hair growth in C3H/HeJ mice. Healthy C57BL/6 mice were randomly divided into two groups: with and without low-level laser treatment. The skin color of each mouse was observed each day. Skin samples were collected for H&E, immunofluorescence, PCR, and western blot analysis, to observe the morphology of hair follicles and detect the expression levels of Wnt10b and β-catenin. Observation of skin color demonstrated that black pigmentation started significantly earlier in the laser group than in the control group. Hair follicle number in both groups showed no difference; however, the hair follicle length presented a significant difference. Wnt10b protein was detected on the second day in hair matrix cells in the LLLT group but not in the control group. PCR and western blot results both illustrated that expression of Wnt10b and β-catenin was significantly higher in the LLLT group than in the control group. Our study illustrated that low-level laser treatment can promote hair regrowth by inducing anagen phase of hair follicles via initiating the Wnt10b/β-catenin pathway.

  2. Expression of the C-terminal family 22 carbohydrate-binding module of xylanase 10B of Clostridium themocellum in tobacco plant

    NARCIS (Netherlands)

    Olawole, O.

    2009-01-01

    Carbohydrate-binding modules have been shown to alter plant cell wall structural architecture. Hence, they have the potential application of being used to engineer the plant to produce tailor-made natural fibers in the cell wall. The Clostridium thermocellum xylanase, Xyn10B, contains two CBMs that

  3. Development of a simple and rapid method of precisely identifying the position of 10B atoms in tissue: an improvement in standard alpha autoradiography.

    Science.gov (United States)

    Tanaka, Hiroki; Sakurai, Yoshinori; Suzuki, Minoru; Masunaga, Shin-ichiro; Takamiya, Koichi; Maruhashi, Akira; Ono, Koji

    2014-03-01

    Boron neutron capture therapy (BNCT) can be utilized to selectively kill cancer cells using a boron compound that accumulates only in cancer cells and not in normal cells. Tumor-bearing animals treated by BNCT are routinely used to evaluate long-term antitumor effects of new boron compounds. Alpha-autoradiography is one of the methods employed in the evaluation of antitumor effects. However, a standard alpha-autoradiography cannot detect the microdistribution of (10)B because of the difficulty associated with the superposition of a tissue sample image and etched pits on a track detector with the etching process. In order to observe the microdistribution of (10)B, some special methods of alpha-autoradiography have been developed that make use of a special track detector, or the atomic force microscope combined with X-ray and UV light irradiation. In contrast, we propose, herein, a simple and rapid method of precisely identifying the position of (10)B using the imaging process and the shape of etched pits, such as their circularity, without the need to use special track detectors or a microscope. A brief description of this method and its verification test are presented in this article. We have established a method of detecting the microdistribution of (10)B with submicron deviation between the position of etched pits and the position of reaction in a tissue sample, for a given circularity of etched pits.

  4. Detection of secondary eclipses of WASP-10b and Qatar-1b in the Ks band and the correlation between Ks-band temperature and stellar activity.

    Science.gov (United States)

    Cruz, Patricia; Barrado, David; Lillo-Box, Jorge; Diaz, Marcos; López-Morales, Mercedes; Birkby, Jayne; Fortney, Jonathan J.; Hodgkin, Simon

    2017-10-01

    The Calar Alto Secondary Eclipse study was a program dedicated to observe secondary eclipses in the near-IR of two known close-orbiting exoplanets around K-dwarfs: WASP-10b and Qatar-1b. Such observations reveal hints on the orbital configuration of the system and on the thermal emission of the exoplanet, which allows the study of the brightness temperature of its atmosphere. The observations were performed at the Calar Alto Observatory (Spain). We used the OMEGA2000 instrument (Ks band) at the 3.5m telescope. The data was acquired with the telescope strongly defocused. The differential light curve was corrected from systematic effects using the Principal Component Analysis (PCA) technique. The final light curve was fitted using an occultation model to find the eclipse depth and a possible phase shift by performing a MCMC analysis. The observations have revealed a secondary eclipse of WASP-10b with depth of 0.137%, and a depth of 0.196% for Qatar-1b. The observed phase offset from expected mid-eclipse was of -0.0028 for WASP-10b, and of -0.0079 for Qatar-1b. These measured offsets led to a value for |ecosω| of 0.0044 for the WASP-10b system, leading to a derived eccentricity which was too small to be of any significance. For Qatar-1b, we have derived a |ecosω| of 0.0123, however, this last result needs to be confirmed with more data. The estimated Ks-band brightness temperatures are of 1647 K and 1885 K for WASP-10b and Qatar-1b, respectively. We also found an empirical correlation between the (R'HK) activity index of planet hosts and the Ks-band brightness temperature of exoplanets, considering a small number of systems.

  5. Observation of nuclei reassembled from demembranated Xenopus sperm nuclei and analysis of their lamina components

    Institute of Scientific and Technical Information of China (English)

    QUJIAN; CHUANMAOZHANG; 等

    1994-01-01

    A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei.Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear memblane,nuclear pore complexes,and decondensed chromatin etc.Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei.Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only egg derived lamin LIII.

  6. Magnetic moments of odd spherical nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Levon, A.I.; Fedotkin, S.N.; Vdovin, A.I.

    1986-06-01

    Using the quasiparticle-phonon model, the magnetic moments of the ground state and several of the excited states are calculated for spherical nuclei. The polarization of the core is taken into account, by means of 1+ phonons, as well as 2/sup +/ and 3/sup -/ excitations, which give a collective contribution to the magnetic moment.

  7. Neutrino Processes with Hot Nuclei in Supernovae

    Science.gov (United States)

    Dzhioev, A. A.; Vdovin, A. I.

    In this paper, we calculate cross sections for charged-current neutrino-nucleus processes occuring under presupernova conditions. To treat thermal effects we extend self-consistent Skyrme-QRPA calculations to finite temperature by using the formalism of thermo field dynamics. The numerical results are presented for the sample nuclei, $^{56}$Fe and $^{82}$Ge

  8. Fisica degli atomi e dei nuclei

    CERN Document Server

    Bernardini, Carlo

    1965-01-01

    Evidenza della struttura atomica della materia ; le proprietà degli atomi e la meccanica atomica ; gli atomi e le radiazioni elettromagnetiche ; struttura microscopica dello stato gassoso ; struttura microscopica dello stato liquido ; struttura microscopica della stato solido ; proprietà elettriche e magnetiche delle sostanze ; proprietà dei nuclei degli atomi ; le particelle elementari.

  9. Precision lifetime measurements in light exotic nuclei

    Science.gov (United States)

    McCutchan, Elizabeth

    2017-01-01

    A new generation of ab-initio calculations, based on realistic two- and three-body forces have had a profound impact on our understanding of nuclei. They have shed light on topics such as the origin of effective forces (like spin-orbit and tensor interactions) and the mechanisms behind cluster and pairing correlations. New precise data are required to both better parameterize the three body forces and to improve numerical methods. A sensitive probe of the structure of light nuclei comes from their electromagnetic transition rates. A refined Doppler Shift Attenuation Method (DSAM) will be outlined which is used to precisely measure lifetimes in light nuclei and helps to reduce and quantity systematic uncertainties in the measurement. Using this careful DSAM, we have made a series of precise measurements of electromagnetic transition strengths in Li isotopes, A =10 nuclei, and the exotic halo nucleus, 12Be. Various phenomena, such as alpha clustering and meson-exchange currents, can be investigated in these seemingly simple systems, while the collection of data spanning stable to neutron-rich, allows us to probe the influence of additional valence neutrons. This talk will report on what has been learned, and the challenges that lie in the future, both in experiment and theory, as we push to describing and measuring even more exotic systems. Work supported by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under contract No. DE-AC02-98CH10886.

  10. Test of Pseudospin Symmetry in Deformed Nuclei

    CERN Document Server

    Ginocchio, J N; Meng, J; Zhou, S G; Zhou, Shan-Gui

    2004-01-01

    Pseudospin symmetry is a relativistic symmetry of the Dirac Hamiltonian with scalar and vector mean fields equal and opposite in sign. This symmetry imposes constraints on the Dirac eigenfunctions. We examine extensively the Dirac eigenfunctions of realistic relativistic mean field calculations of deformed nuclei to determine if these eigenfunctions satisfy these pseudospin symmetry constraints.

  11. Magnetic Dipole Sum Rules for Odd Nuclei

    CERN Document Server

    Ginocchio, J N

    1997-01-01

    Sum rules for the total- and scissors-mode M1 strength in odd-A nuclei are derived within the single-j interacting boson-fermion model. We discuss the physical content and geometric interpretation of these sum rules and apply them to ^{167}Er and ^{161}Dy. We find consistency with the former measurements but not with the latter.

  12. Spectroscopic Studies of Exotic Nuclei at ISOLDE

    CERN Multimedia

    2002-01-01

    Experiment IS50 is designed to: a) Investigate the full range of the @b strength function of heavy (A~$>$~48)~K nuclei b)~Study the decay of isomeric states in n-deficient bromine nuclei (A~=~72 and 70). The heavy K isotopes appeared to have complex decay schemes, including feeding by the @b-decay of levels having open neutron channels (Beta decay energy Q(@b) exceeds neutron binding energy S^n); in addition, a large fraction of the delayed transitions populate excited levels in the daughter nuclei. The allowed @b-decay selects states in the daughter nucleus with wave functions having a large overlap with the initial state. Hence, the @b strength functions, deduced from these deca reveal simple structures correlated to the particle-hole excitation energies in the Ca nuclei. These results are valuable for the application of the shell-model calculations far from stability. The delayed neutron spectra are measured with a large area curved scintillator in coincidence either with high resolution Ge(Li) detectors, ...

  13. Physics of the continuum of borromean nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Vaagen, J.S.; Rogde, T. [Dept. of Physics, Univ. of Bergen (Norway); Danilin, B.V. [RRC The Kurchatov Inst., Kurchatov, Moscow (Russian Federation); Ershov, S.N. [JINR, Dubna, Moscow (Russian Federation); Thompson, I.J. [Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom); Zhukov, M.V. [Chalmers Univ. of Technology and Goeteborg Univ., Goeteborg (Sweden); RNBT Collaboration

    1998-06-01

    The continuum states of two-neutron halo nuclei are calculated in the method of hyperspherical harmonics. Using DWIA theory appropriate for dilute halo matter we have probed the structure of the low-lying {sup 6}He continuum via calculations of charge-exchange and inelastic scattering. (orig.)

  14. On the Elastic Scattering of Heavy Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, J. S.; Park, S. C.; Turner, J. E.

    1960-01-01

    A program is presented for determining the differential cross-section for the elastic scattering of heavy nuclei. It utilizes the unitary property of the S-matrix and a less drastic L-dependence of the absorption than the sharp cut-off model of Blair. it is shown that experimental data can be fitted quite well. (auth)

  15. Comment on Breakup Densities of Hot Nuclei

    CERN Document Server

    Viola, V E; Natowitz, J B; Yennello, S J

    2006-01-01

    In [1,2]the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing energy. Subsequently, Raduta et al. [3] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this letter we examine this apparent inconsistency.

  16. Building Atomic Nuclei with the Dirac Equation

    OpenAIRE

    Serot, Brian D.

    2003-01-01

    The relevance of the Dirac equation for computations of nuclear structure is motivated and discussed. Quantitatively successful results for medium- and heavy-mass nuclei are described, and modern ideas of effective field theory and density functional theory are used to justify them.

  17. Heavy Mesons in Nuclear Matter and Nuclei

    CERN Document Server

    Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M

    2014-01-01

    Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.

  18. Spectroscopic factors for two-proton radioactive nuclei

    Indian Academy of Sciences (India)

    Chinmay Basu

    2004-11-01

    Spectroscopic factors for two-proton emitting nuclei are discussed in the framework of the BCS (Bardeen–Cooper–Schriefer) model. Calculations carried out for the two-proton unstable 45Fe, 48Ni and 54Zn nuclei are presented.

  19. Whole-Cell Properties of Cerebellar Nuclei Neurons In Vivo

    NARCIS (Netherlands)

    Canto, Cathrin B; Witter, L.; De Zeeuw, C.I.

    2016-01-01

    Cerebellar nuclei neurons integrate sensorimotor information and form the final output of the cerebellum, projecting to premotor brainstem targets. This implies that, in contrast to specialized neurons and interneurons in cortical regions, neurons within the nuclei encode and integrate complex

  20. Incidence of centrally positioned nuclei in mouse masticatory muscle fibers

    DEFF Research Database (Denmark)

    Vilmann, A; Vilmann, H; Kirkeby, S

    1989-01-01

    Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei......, the frequency in a given muscle was apparently age-independent. A connection between fiber type and centrally positioned nuclei is suggested....

  1. Flux of cosmic ray heavy nuclei enders behind low shielding

    CERN Document Server

    Allkofer, O C

    1975-01-01

    The authors investigate the number of stopping nuclei per cm/sup 3/ tissue hour as a function of absorbing material thickness. Fragmentation probabilities of heavy nuclei were deduced from the measured attenuation of the heavy nuclei flux in the atmosphere. Comparison is made with the results of the Biostack I experiment on board Apollo 16. (11 refs).

  2. The temperature dependence of the magnetoelastic characteristics of cores for force sensors utilizing Fe70Ni8Si10B12 amorphous alloy

    Indian Academy of Sciences (India)

    Roman Szewczyk; Adam Bieńkowski; Jacek Salach

    2008-09-01

    This paper presents the results of investigation on the influence of temperature on magnetoelastic characteristics of the two ring-shaped cores, made of Fe70Ni8Si10B12 amorphous alloy. The cores were annealed for 1 h at 350 and 400° C, respectively. The compressive force was applied perpendicular to the direction of the magnetizing field in the sample. Special cylindrical backing enables application of the uniform compressive stress to the wound ring sample. A resistive furnace heated the experimental set-up. Results presented in the paper indicate a significant influence of the temperature on the magnetoelastic characteristics of Fe70Ni8Si10B12 amorphous alloy. Information about the magnetoelastic characteristics of this material may be useful in the magnetoelastic sensor development. Also this will create new possibilities in the development of physical model of magnetoelastic effect.

  3. Effects of employing a 10B-carrier and manipulating intratumour hypoxia on local tumour response and lung metastatic potential in boron neutron capture therapy

    Science.gov (United States)

    Masunaga, S; Sakurai, Y; Tanaka, H; Suzuki, M; Liu, Y; Kondo, N; Maruhashi, A; Kinashi, Y; Ono, K

    2012-01-01

    Objectives To evaluate the effects of employing a 10B-carrier and manipulating intratumour hypoxia on local tumour response and lung metastatic potential in boron neutron capture therapy (BNCT) by measuring the response of intratumour quiescent (Q) cells. Methods B16-BL6 melanoma tumour-bearing C57BL/6 mice were continuously given 5-bromo-2′-deoxyuridine (BrdU) to label all proliferating (P) cells. The tumours received reactor thermal neutron beam irradiation following the administration of a 10B-carrier [L-para-boronophenylalanine-10B (BPA) or sodium mercaptoundecahydrododecaborate-10B (BSH)] in combination with an acute hypoxia-releasing agent (nicotinamide) or mild temperature hyperthermia (MTH). Immediately after the irradiation, cells from some tumours were isolated and incubated with a cytokinesis blocker. The responses of the Q and total (P+Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumour-bearing mice, macroscopic lung metastases were enumerated 17 days after irradiation. Results BPA-BNCT increased the sensitivity of the total tumour cell population more than BSH-BNCT. However, the sensitivity of Q cells treated with BPA was lower than that of BSH-treated Q cells. With or without a 10B–carrier, MTH enhanced the sensitivity of the Q cell population. Without irradiation, nicotinamide treatment decreased the number of lung metastases. With irradiation, BPA-BNCT, especially in combination with nicotinamide treatment, showed the potential to reduce the number of metastases more than BSH-BNCT. Conclusion BSH-BNCT in combination with MTH improves local tumour control, while BPA-BNCT in combination with nicotinamide may reduce the number of lung metastases. PMID:22391496

  4. Effect of thermal treatment on the magnetization processes of nanocrystalline Fe{sub 80}Ge{sub 3}Nb{sub 10}B{sub 7} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mao Xingyu, E-mail: maoxingyu@jmu.edu.cn [Institute of Science, Jimei University, 361021 (China); Ke Zhijian; Zou Weidong; Lin Qiubao [Institute of Science, Jimei University, 361021 (China); Qin Zhijie [Department of Physics, Zhengzhou University, 450001 (China); Wu Yan [Institute of Science, Jimei University, 361021 (China)

    2012-02-15

    The dynamic magnetization processes of nanocrystalline Fe{sub 80}Ge{sub 3}Nb{sub 10}B{sub 7} alloys after annealing at different temperatures are studied through the permeability spectroscopy. Three steps of crystallization are found when amorphous Fe{sub 80}Ge{sub 3}Nb{sub 10}B{sub 7} alloys are heated from 300to 1200 K. The dominant magnetization process varies with different annealing temperatures. Domain wall bulging is the main magnetization mechanism under weak applied field. When the applied field exceeds pinning field H{sub p}, the depinning-involved domain wall displacement occurs. Different annealing temperature results in different H{sub p}. The lower value of {mu}' and high relaxation frequency after heating at 923 and 973 K are due to the strengthened domain wall pinning and the increase of magnetocrystalline anisotropy. - Highlights: > Nanocrystallization and magnetic properties of Fe{sub 80}Ge{sub 3}Nb{sub 10}B{sub 7} alloy were studied. > Permeability spectra reveals that magnetization process varies with the annealing time. > 973 K annealing may result in Fe{sub 3}Ge, which deteriorates soft magnetism. > Domain wall bulging and displacement are main magnetization mechanisms. > Pinning sites and their distribution determine the magnetic performance.

  5. Measurement of the 10 keV resonance in the $^{10}$B($p, \\alpha_0$)$^7$Be reaction via the Trojan Horse Method

    CERN Document Server

    Spitaleri, C; Puglia, S M R; Romano, S; La Cognata, M; Crucilla, V; Pizzone, R G; Rapisarda, G G; Sergi, M L; Del Santo, M Gimenez; Carlin, N; Munhoz, M G; Souza, F A; de Toledo, A Szanto; Tumino, A; Irgaziev, B; Mukhamedzhanov, A; Tabacaru, G; Burjan, V; Kroha, V; Hons, Z; Mrazek, J; Zhou, Shu-Hua; Li, Chengbo; Wen, Qungang; Wakabayashi, Y; Yamaguchi, H

    2014-01-01

    The $^{10}$B(p,$\\alpha_0$)$^7$Be bare nucleus astrophysical S(E)-factor has been measured for the first time at energies from about 100 keV down to about 5 keV by means of the Trojan Horse Method (THM). In this energy region, the S(E)-factor is strongly dominated by the 8.699 MeV $^{11}$C level (J$^{\\pi}$=$\\frac{5}{2}$$^+$), producing an s-wave resonance centered at about 10 keV in the entrance channel. Up to now, only the high energy tail of this resonant has been measured, while the low-energy trend is extrapolated from the available direct data. The THM has been applied to the quasi-free $^2$H($^{10}$B,$\\alpha_0$$^7$Be)n reaction induced at a boron-beam energy of 24.5 MeV. An accurate analysis brings to the determination of the $^{10}$B(p,$\\alpha_0$)$^7$Be S(E)-factor and of the corresponding electron screening potential $U_e$, thus giving for the first time an independent evaluation of it.

  6. High-Resolution Spectra of the 10B18O and 11B18O: Rotational Analysis of the B-X Bands

    Institute of Scientific and Technical Information of China (English)

    V.Bojovic; A.Anti6-Jovanovi(c); M.Kuzmanovi(c)

    2005-01-01

    @@ Emission spectra of 10B18O and 11 B18O isotopomers in the 230-330 nm region have been investigated by means of conventional high-resolution spectroscopy.The molecules were produced in a low-pressure arc by discharging 8 Torr of mixture containing argon and oxygen 18 in the ratio of 4:1 and the spectra have been recorded using Ebert-type spectrograph.The boron needed to produce BO has been present in the system as amorphous powder with natural abundance of 10B and 11 B.Rotational analysis of the 0, 0 and 0, 1 bands has been performed and spectroscopic constants have been extracted.The results have allowed first determination of the equilibrium rotational constants Be and De for both isotope species 10B18O and 11B18O in their lower electronic state.Assuming a linear dependence of Be on (v + 1/2), the value of equilibrium distance re in the lower state has been derived.

  7. Population of rotational bands in superheavy nuclei

    Directory of Open Access Journals (Sweden)

    Antonenko N.V.

    2012-02-01

    Full Text Available Using the statistical approach, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca, 2n254No, 206Pb(48Ca, 2n252No, and 204Hg(48Ca, 2n250Fm. We calculate relative intensities of E2-transitions between the rotational states and entry spin distributions of the residual nuclei, evaporation residue cross sections, and excitation functions for these reactions. Fermi-gas model is used for the calculation of level density, and damping of shell effects both with excitation energy and angular momentum is taking into account. The results are in a good agreement with the experiment data.

  8. DAPI fluorescence in nuclei isolated from tumors.

    Science.gov (United States)

    Krishan, Awtar; Dandekar, Payal D

    2005-08-01

    In DNA histograms of some human solid tumors stained with nuclear isolation medium--4,6-diamidino-2-phenylindole dihydrochloride (NIM-DAPI), the coefficient of variation (CV) of the G0/G1 peak was broad, and in nuclear volume vs DNA scattergrams, a prominent slope was seen. To determine the cause for this, nuclei from frozen breast tumors were stained with NIM-DAPI and analyzed after dilution or resuspension in PBS. In two-color (blue vs red) analysis, most of the slope and broad CV was due to red fluorescence of nuclei stained with NIM-DAPI, which was reduced on dilution or resuspension in PBS, resulting in elimination of the slope and tightening of the CV.

  9. Clustering in stable and exotic nuclei

    CERN Document Server

    Beck, C

    2016-01-01

    Since the pioneering discovery of molecular resonances in the 12C+12C reaction more than half a century ago a great deal of research work has been undertaken in alpha clustering. Our knowledge on physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. The occurrence of "exotic" shapes and Bose-Einstein alpha condensates in light N=Z alpha-conjugate nuclei is investigated. Various approaches of the superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Evolution of clustering from stability to the drip-lines is examined: clustering aspects are, in particular, discussed for light exotic nuclei with large neutron excess such as neutron-rich Oxygen isotopes with their complete spectroscopy.

  10. Shell model for warm rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, M.; Yoshida, K. [Kyoto Univ. (Japan); Dossing, T. [Univ. of Copenhagen (Denmark)] [and others

    1996-12-31

    Utilizing a shell model which combines the cranked Nilsson mean-field and the residual surface and volume delta two-body forces, the authors discuss the onset of rotational damping in normal- and super-deformed nuclei. Calculation for a typical normal deformed nucleus {sup 168}Yb indicates that the rotational damping sets in at around 0.8 MeV above the yrast line, and about 30 rotational bands of various length exists at a given rotational frequency, in overall agreement with experimental findings. It is predicted that the onset of rotational damping changes significantly in different superdeformed nuclei due to the variety of the shell gaps and single-particle orbits associated with the superdeformed mean-field.

  11. Collective properties of drip-line nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hamamoto, I. [Univ. of Lund (Sweden); Sagawa, H. [Univ. of Aizu, Fukushima (Japan)

    1996-12-31

    Performing the spherical Hartree-Fock (HF) calculations with Skyrme interactions and, then, using RPA solved in the coordinate space with the Green`s function method, the authors have studied the effect of the unique shell structure as well as the very low particle threshold on collective modes in drip line nuclei. In this method a proper strength function in the continuum is obtained, though the spreading width of collective modes is not included. They have examined also one-particle resonant states in the obtained HF potential. Unperturbed particle-hole (p-h) response functions are carefully studied, which contain all basic information on the exotic behaviour of the RPA strength function in drip line nuclei.

  12. Disappearance of collective motion in hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Santonocito, D.; Piattelli, P.; Agodi, C.; Alba, R.; Bellia, G.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Hongmei, F.; Maiolino, C.; Migneco, E.; Sapienza, P. [INFN-LNS, Laboratori Nazionali del Sud, Catania (Italy); Blumenfeld, Y.; Delaunay, F.; Frascaria, N.; Lima, V.; Scarpaci, J. [Institut de Physique Nucleaire, IN2P3-CNRS, 91 - Orsay (France); Migneco, E. [Catania Univ., Dipartimento di Fisica (Italy)

    2003-07-01

    The evolution of the GDR {gamma} yield for excitation energies between 160 and 300 MeV has been investigated in nuclei of mass A {approx} 126 through the reactions {sup 116}Sn + {sup 12}C and {sup 24}Mg at 17 and 23 A*MeV. Gamma-rays were detected with MEDEA array in coincidence with residues detected in MACISTE. The evolution of the GDR parameters has been investigated as a function of the linear momentum transferred to the fused system. This procedure allowed us to select hot nuclei produced in incomplete fusion reactions with different excitation energies. The analysis of the {gamma} spectra and their comparison with CASCADE calculations is presented. Results suggest a saturation of the GDR yield between 200 and 300 MeV excitation energy. (authors)

  13. Simulation of nuclei morphologies for binary alloy

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We study the critical nuclei morphologies of a binary alloy by the string method. The dynamic equation of the string, connecting the metastable phase (liquid) and stable phase (solid), is governed by Helmholtz free energy for the binary alloy system at a given temperature. The stationary string through the critical nucleus (saddle point) is obtained if the relaxation time of the string is su?ciently large. The critical nucleus radius and energy barrier to nucleation of a pure alloy with isotropic interface energy in two and three dimensions are calculated, which are consistent with the classical nucleation theory. The critical nuclei morphologies are sensitive to the anisotropy strength of interface energy and interface thickness of alloy in two and three dimensions. The critical nucleus and energy barrier to nucleation become smaller if the anisotropy strength of the interface energy is increased, which means that it is much easier to form a stable nucleus if the anisotropy of the interface energy is considered.

  14. Gamma spectroscopy of neutron rich actinide nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Birkenbach, Benedikt; Geibel, Kerstin; Vogt, Andreas; Hess, Herbert; Reiter, Peter; Steinbach, Tim; Schneiders, David [Koeln Univ. (Germany). IKP; Collaboration: AGATA-Collaboration

    2013-07-01

    Excited states in neutron-rich actinide Th and U nuclei were investigated after multi nucleon transfer reactions employing the AGATA demonstrator and PRISMA setup at LNL (INFN, Italy). A primary {sup 136}Xe beam of 1 GeV hitting a {sup 238}U target was used to produce the nuclei of interest. Beam-like reaction products of Xe- and Ba isotopes after neutron transfer were selected by the PRISMA spectrometer. The recoil like particles were registered by a MCP detector inside the scattering chamber. Coincident γ-rays from excited states in beam and target like particles were measured with the position sensitive AGATA HPGe detectors. Improved Doppler correction and quality of the γ-spectra is based on the novel γ-ray tracking technique which was successfully exploited. First results on the collective properties of various Th and U isotopes are discussed.

  15. Isospin Mixing In N $\\approx$ Z Nuclei

    CERN Multimedia

    Srnka, D; Versyck, S; Zakoucky, D

    2002-01-01

    Isospin mixing in N $\\approx$ Z nuclei region of the nuclear chart is an important phenomenon in nuclear physics which has recently gained theoretical and experimental interest. It also forms an important nuclear physics correction in the precise determination of the $ft$-values of superallowed 0$^+ \\rightarrow 0^+ \\beta$- transitions. The latter are used in precision tests of the weak interaction from nuclear $\\beta$- decay. We propose to experimentally measure isospin mixing into nuclear ground states in the N $\\approx$ Z region by determining the isospin forbidden Fermi-component in the Gamow-Teller dominated $J^{\\pi} \\rightarrow J^{\\pi} \\beta$- transitions through the observation of anisotropic positron emission from oriented nuclei. First measurements were carried out with $^{71}$As and are being analyzed now.

  16. Antiproton Induced Fission and Fragmentation of Nuclei

    CERN Multimedia

    2002-01-01

    The annihilation of slow antiprotons with nuclei results in a large highly localized energy deposition primarily on the nuclear surface. \\\\ \\\\ The study of antiproton induced fission and fragmentation processes is expected to yield new information on special nuclear matter states, unexplored fission modes, multifragmentation of nuclei, and intranuclear cascades.\\\\ \\\\ In order to investigate the antiproton-nucleus interaction and the processes following the antiproton annihilation at the nucleus, we propose the following experiments: \\item A)~Measurement of several fragments from fission and from multifragmentation in coincidence with particle spectra, especially neutrons and kaons. \\item B)~Precise spectra of $\\pi$, K, n, p, d and t with time-of-flight techniques. \\item C)~Installation of the Berlin 4$\\pi$ neutron detector with a 4$\\pi$ Si detector placed inside for fragments and charged particles. This yields neutron multiplicity distributions and consequently distributions of thermal excitation energies and...

  17. Electromagnetic interactions with nuclei and nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, S.T.; Sealock, R.M.

    1990-11-10

    This report discusses the following topics: general LEGS work; photodisintegration of the deuteron; progress towards other experiments; LEGS instrumentation; major LEGS software projects; NaI detector system; nucleon detector system; waveshifting fibers; EGN prototype detector for CEBAF; photon beam facility at CEBAF; delta electroproduction in nuclei; quasielastic scattering and excitation of the Delta by {sup 4}He(e,e{prime}); and quasielastic scattering at high Q{sup 2}.

  18. Spin-isospin resonances in nuclei

    NARCIS (Netherlands)

    Fujiwara, M; Akimune, H; Daito, [No Value; Ejiri, H; Fujita, Y; Greenfield, MB; Harakeh, MN; Inomata, T; Janecke, J; Nakayama, S; Takemura, N; Tamii, A; Tanaka, M; Toyokawa, H; Yosoi, M

    1996-01-01

    Spin-isospin excitations in nuclei have been investigated via the (He-3,t) reaction at 450 MeV. The volume integrals of the effective interactions J(sigma tau) and J(tau) for the (He-3,t) reaction at 450 MeV have been empirically determined to be 172+/-17 MeV-fm(3) and 53+/-5 MeV-fm(3), respectively

  19. Understanding active galactic nuclei: peeling the onion.

    Science.gov (United States)

    Krolik, J. H.

    A brief review is presented of selected current problems in understanding active galactic nuclei, with special emphasis on the contributions that X-ray observations can make. Questions having to do with: how the character of the host galaxy influences nuclear activity; emission line regions; the border between the nucleus and the stellar portion of the active galaxy; radiation of the nonthermal continuum; and the possible existence of an accretion disk are touched upon.

  20. Light nuclei production in heavy ion collisions

    CERN Document Server

    Khan, K H; Wazir, Z; Khan, E U; Haseeb, Mahnaz Q; Ajaz, M

    2009-01-01

    Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.

  1. SEARCH FOR NUCLEI CONTAINING TWO STRANGE QUARKS.

    Energy Technology Data Exchange (ETDEWEB)

    MAY,M.

    1997-10-13

    This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.

  2. Search for nuclei containing two strange quarks

    Energy Technology Data Exchange (ETDEWEB)

    May, M.

    1997-12-31

    This paper discusses a search for nuclei containing two strange quarks performed at Brookhaven National Laboratory. The goals and approach of experiment E885 are reviewed. Preliminary missing mass spectra for a subset of the data are presented, showing sensitivity for {Xi} hypernuclei and H particle searches. Existence of an angular correlation between pions in the sequential decay of {Lambda}{Lambda} hypernuclei is suggested on theoretical grounds.

  3. Green's function calculations of light nuclei

    Science.gov (United States)

    Sun, ZhongHao; Wu, Qiang; Xu, FuRong

    2016-09-01

    The influence of short-range correlations in nuclei was investigated with realistic nuclear force. The nucleon-nucleon interaction was renormalized with V lowk technique and applied to the Green's function calculations. The Dyson equation was reformulated with algebraic diagrammatic constructions. We also analyzed the binding energy of 4He, calculated with chiral potential and CD-Bonn potential. The properties of Green's function with realistic nuclear forces are also discussed.

  4. AMS with light nuclei at small accelerators

    Science.gov (United States)

    Stan-Sion, C.; Enachescu, M.

    2017-06-01

    AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.

  5. Fayans functional for deformed nuclei. Uranium region

    CERN Document Server

    Tolokonnikov, S V; Kortelainen, M; Lutostansky, Yu S; Saperstein, E E

    2015-01-01

    Fayans energy density functional (EDF) FaNDF^0 has been applied to the nuclei around uranium region. Ground state characteristics of the Th, U and Pu isotopic chains, up to the two-neutron drip line, are found and compared with predictions from several Skyrme EDFs. The two-neutron drip line is found for FaNDF^0, SLy4 and SkM^* EDFs for a set of elements with even proton number, from Pb up to Fm.

  6. Fusion excitation functions involving transitional nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.E.; Jiang, C.L.; Esbensen, H. [and others

    1995-08-01

    Measurements of fusion excitation functions involving transitional nuclei {sup 78}Kr and {sup 100}Mo showed a different behavior at low energies, if compared to measurements with {sup 86}Kr and {sup 92}Mo. This points to a possible influence of nuclear structure on the fusion process. One way to characterize the structure of vibrational nuclei is via their restoring force parameters C{sub 2} which can be calculated from the energy of the lowest 2{sup +} state and the corresponding B(E2) value. A survey of the even-even nuclei between A = 28-150 shows strong variations in C{sub 2} values spanning two orders of magnitude. The lowest values for C{sub 2} are observed for {sup 78}Kr, {sup 104}Ru and {sup 124}Xe followed by {sup 74,76}Ge, {sup 74,76}Se, {sup 100}Mo and {sup 110}Pd. In order to learn more about the influence of {open_quotes}softness{close_quotes} on the sub-barrier fusion enhancement, we measured cross sections for evaporation residue production for the systems {sup 78}Kr + {sup 104}Ru and {sup 78}Kr + {sup 76}Ge with the gas-filled magnet technique. For both systems, fusion excitation functions involving the closed neutron shell nucleus {sup 86}Kr were measured previously. The data are presently being analyzed.

  7. Ice Nuclei Measurements From AMAZE-08

    Science.gov (United States)

    Prenni, A. J.; Petters, M. D.; Demott, P. J.; Kreidenweis, S. M.

    2008-12-01

    The Amazon Basin is the largest intact tropical forest in the world, covering four million square kilometers. With large emissions of gases and particulate matter, this ecosystem plays an important role in the global atmosphere. Assessing gaseous and particulate emissions from the Amazon Basin and the climatic effects of these emissions has been the focus of several major field campaigns. However, until recently there have been no measurements aimed at characterizing ice nuclei (IN) in this region. Such measurements are critical for understanding cloud and precipitation processes. In this paper, we present recent ice nuclei measurements from the AMazonian Aerosol characteriZation Experiment 2008 (AMAZE-08). These data were collected during the rainy season at the Instituto Nacional de Pesquisas da Amazonia TT34 tower northeast of Manaus, Brazil. Results are presented for ice nuclei number concentration and elemental composition collected using the Colorado State University Continuous Flow ice thermal Diffusion Chamber (CFDC). The data suggest that, like many regions of the world, IN concentrations are largely controlled by the presence of desert dust, in this case transported from Africa. However, carbonaceous particles also made up a significant fraction of IN. Based on complementary aerosol composition measurements, we consider possible sources of this carbonaceous fraction.

  8. Electron and pion scattering off nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Buss, O.; Mosel, U. [Inst. fuer Theoretische Physik, Univ. Giessen (Germany); Alvarez-Ruso, L. [Dept. de Fisica Teorica and IFIC, Centro Mixto Univ. de Valencia-CSIC (Spain)

    2007-07-01

    We present a treatment of pion and electron scattering off nuclei within the framework of a Boltzmann-Uehling-Uhlenbeck (BUU) transport model. In this approach we realize a full coupled channel treatment and include medium modifications such as mean-field potentials, Fermi motion and width modifications. We have applied the GiBUU model to the description of the double charge exchange (DCX) reaction of pions with different nuclear targets at incident kinetic energies of 120-180 MeV. The DCX process is highly sensitive to details of the interactions of pions with the nuclear medium and, therefore, represents a major benchmark for any model of pion scattering off nuclei at low and intermediate energies. We discuss the impact of surface effects and the dependence on the nuclear mass number. We have achieved a good quantitative agreement with the extensive data set obtained at LAMPF. Furthermore, we present a description of electron induced reactions, i.e. pion production, off nuclei. We consider the scattering of electrons off the bound nucleons in an impulse approximation and investigate medium modifications to exclusive particle production cross sections and compare our results to available data. (orig.)

  9. Adiabatic fission barriers in superheavy nuclei

    CERN Document Server

    Jachimowicz, P; Skalski, J

    2016-01-01

    Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy we calculated static fission barriers $B_{f}$ for 1305 heavy and superheavy nuclei $98\\leq Z \\leq 126$, including even - even, odd - even, even - odd and odd - odd systems. For odd and odd-odd nuclei, adiabatic potential energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from the 10-th below to the 10-th above the Fermi level. The parameters of the model that have been fixed previously by a fit to masses of even-even heavy nuclei were kept unchanged. A search for saddle points has been performed by the "Imaginary Water Flow" method on a basic five-dimensional deformation grid, including triaxiality. Two auxiliary grids were used for checking the effects of the mass asymmetry and hexadecapole non-axiallity. The ground states were found by energy minimization over configurations and deformations...

  10. Chromatin associations in Arabidopsis interphase nuclei

    Directory of Open Access Journals (Sweden)

    Veit eSchubert

    2014-11-01

    Full Text Available The arrangement of chromatin within interphase nuclei seems to be caused by topological constraints and related to gene expression depending on tissue and developmental stage. In yeast and animals it was found that homologous and heterologous chromatin association are required to realize faithful expression and DNA repair. To test whether such associations are present in plants we analysed Arabidopsis thaliana interphase nuclei by FISH using probes from different chromosomes. We found that chromatin fibre movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances. The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns.Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its ten centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus. Nevertheless, chromatin movement enables a flexible spatial genome arrangement in plant nuclei.

  11. Wave function calculations in finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, S.C.

    1993-07-01

    One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: (1) specification of the Hamiltonian, and (2) calculation of the ground (or excited) states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependencies. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At Argonne and Urbana, the authors have been following a program of developing realistic NN and NNN interactions and the methods necessary to compute nuclear properties from variational wave functions suitable for these interactions. The wave functions are used to compute energies, density distributions, charge form factors, structure functions, momentum distributions, etc. Most recently they have set up a collaboration with S. Boffi and M. Raduci (University of Pavia) to compute (e,e{prime}p) reactions.

  12. Wave function calculations in finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, S.C.

    1993-01-01

    One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: (1) specification of the Hamiltonian, and (2) calculation of the ground (or excited) states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependencies. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At Argonne and Urbana, the authors have been following a program of developing realistic NN and NNN interactions and the methods necessary to compute nuclear properties from variational wave functions suitable for these interactions. The wave functions are used to compute energies, density distributions, charge form factors, structure functions, momentum distributions, etc. Most recently they have set up a collaboration with S. Boffi and M. Raduci (University of Pavia) to compute (e,e[prime]p) reactions.

  13. Multi-K¯ nuclei and kaon condensation

    Science.gov (United States)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    2008-04-01

    We extend previous relativistic mean-field (RMF) calculations of multi-K¯ nuclei, using vector boson fields with SU(3) PPV coupling constants and scalar boson fields constrained phenomenologically. For a given core nucleus, the resulting K¯ separation energy BK¯, as well as the associated nuclear and K¯-meson densities, saturate with the number κ of K¯ mesons for κ>κsat~10. Saturation appears robust against a wide range of variations, including the RMF nuclear model used and the type of boson fields mediating the strong interactions. Because BK¯ generally does not exceed 200 MeV, it is argued that multi-K¯ nuclei do not compete with multihyperonic nuclei in providing the ground state of strange hadronic configurations and that kaon condensation is unlikely to occur in strong-interaction self-bound strange hadronic matter. Last, we explore possibly self-bound strange systems made of neutrons and K¯0 mesons, or protons and K- mesons, and study their properties.

  14. Resolving the titer of murine cytomegalovirus by plaque assay using the M2-10B4 cell line and a low viscosity overlay

    Science.gov (United States)

    2014-01-01

    Background Murine cytomegalovirus (MCMV) is increasingly used as an infectious model to investigate host-pathogen interactions in mice. Detailed methods have been published for using primary murine embryonic fibroblasts (MEFs) for preparing stocks and determining viral titers of MCMV. For determining the titer of MCMV by plaque assay, these methods rely on a high viscosity media that restricts viral spreading through the supernatant of the culture, but is also usually too viscous to pipet. Moreover, MEFs must be repeatedly generated and can vary widely from batch-to-batch in purity, proliferation rates, and the development of senescence. In contrast, the M2-10B4 bone marrow stromal cell line (ATCC # CRL-1972), which is also permissive for MCMV, has been reported to produce high-titer stocks of MCMV and has the considerable advantages of growing rapidly and consistently. However, detailed methods using these cells have not been published. Methods We modified existing protocols to use M2-10B4 cells for measuring MCMV titers by plaque assay. Results We found that MCMV plaques could be easily resolved on monolayers of M2-10B4 cells. Moreover, plaques formed normally even when cultures of M2-10B4 cells were less than 50% confluent on the day of infection, as long as we also used a reduced viscosity overlay. Conclusions Overall, our protocol enabled us to use a consistent cell line to assess viral titers, rather than repeatedly producing primary MEFs. It also allowed us to start the assay with 4-fold fewer cells than would be required to generate a confluent monolayer, reducing the lead-time prior to the start of the assay. Finally, the reduced viscosity CMC could be handled by pipet and did not need to be pre-mixed with media, thus increasing its shelf-life and ease-of-use. We describe our results here, along with detailed protocols for the use of the M2-10B4 cell lines to determine the titer and grow stocks of MCMV. PMID:24742045

  15. Study of microstructure and correlative magnetic property in bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Man, H.; Xu, H. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Liu, H.W. [The Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Tan, X.H., E-mail: tanxiaohua123@163.com [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Peng, J.C.; Bai, Q. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet was obtained by the simple process of copper mold casting and subsequent annealed at 943 K. Black-Right-Pointing-Pointer The relationship between microstructures and correlative magnetic property of Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy was investigated. Black-Right-Pointing-Pointer The high value of intrinsic coercivity of 1191 kA/m was obtained due to the existence of hard magnetic Nd{sub 2}Fe{sub 14}B phase. - Abstract: The correlation between microstructure and magnetic property of a bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy are investigated. The microstructure of the as-cast Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy shows a small amount of NbFeB phase with a grain size of 500 nm embedded in an amorphous matrix. The as-cast sample shows soft magnetic behavior at room temperature, after a heat treatment the hard magnetic properties are observed. A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet is obtained with an intrinsic coercivity ({sub i}H{sub c}) of 1191 kA/m and a maximum energy product ((BH){sub max}) of 31.7 kJ/m{sup 3} after annealing at 943 K for 20 min. The corresponding microstructure consists of Nd{sub 2}Fe{sub 14}B, NdFe{sub 4}B{sub 4} and NbFeB phases. The existence of the hard magnetic Nd{sub 2}Fe{sub 14}B phase is the reason resulting in a high value of {sub i}H{sub c}. On the other hand, the influences of NdFe{sub 4}B{sub 4} and NbFeB phases in the annealed specimen on the magnetic properties are also discussed.

  16. Synthesis of superheavy nuclei with 238U target

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 238U target is systematically studied.The results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z increasing.The cross sections of the superheavy nuclei at Z = 112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

  17. Synthesis of superheavy nuclei with 238U target

    Institute of Scientific and Technical Information of China (English)

    LIU ZuHua; BAO JingDong

    2009-01-01

    The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 238u target is systematically studied.The results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z increasing.The cross sections of the superheavy nuclei at Z=112 and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

  18. Statistical properties of quantum spectra in nuclei

    Institute of Scientific and Technical Information of China (English)

    WU; Xizhen

    2001-01-01

    [1]Wu Xizhen,Sakata,F.,Zhuo Yizhong et al.,Dynamic realization of statistical state in finite systems,Phys.ReV.C,1996,53:1233-1244.[2]Weidenmüller,H.A.,Statistical theory of nuclear reactions and the Gaussian Othogonal Ensemble,Annals of Physics,1984,158:120-141.[3]Hag,R.U.,Pandey,A.,Bohigas,O.,Fluctuation properties of nuclear energy levels:Do theory and experiment agree? Phys.Rev.Lett.,1982,48:1086-1089.[4]Wu Xizhen,Gu Jianzhong,Iwamoto,A.,Statistical properties of quasiparticle spectra in deformed nuclei,Phys.Rev.C,1999,59:215-220.[5]Garrett,J.D.,Robinson,J.Q.,Foglia,A.J.et al.,Nuclear level repulsion and order vs chaos,Phys.Lett.B,1997,392:24-29.[6]Bohigas,O.,Hag,R.U.,Pandy,A.,Fluctuation properties of nuclear energy levels and widths comparison of theory with experiment,in Nuclear Data for Science and Technology (ed.Bockhoff,K.H.),Dordrecht:Reidel,1983,809-813.[7]Heiss,W.D.,Nazmitdinov,R.G.,Radu,S.,Chaos in axially symmetric potentials with Octupole deformation,Phys.Rev.Lett.,1994,72:2351-2354.[8]Wu Xizhen,Gu Jianzhong,Zhuo Yizhong et al.,Possible understanding of hyperdeformed 144-146Ba nuclei appearing in the spontaneous fission of 252Cf,Phys.Rev.Lett.,1997,79:4542-4545.[9]Ter-Akopian,G.M.,Hamilton,J.H.,Oganessian,Y.T.et al.,New spontaneous fission mode for 252Cf:Indication of hyperdeformed 144,145,146Ba at scission,Phys.Rev.Lett.,1996,77:32-35.[10]Adamian,G.G.,Antonenko,N.V.,Ivanova,S.P.et al.,Problems in description of fusion of heavy nuclei in the two-center shell model approach,Nucl.Phys.A,1999,646:29-52.[11]Hofmann,H.,A quantal transport theory for nuclear collective motion:the metrits of a locally harmonic approximation method,Phys.Rep.,1997,284:139-380.[12]Gu Jianzhong,Wu Xizhen,Zhuo Yizhong,Quantum chaotic motion of a single particle in heavy nuclei,Nucl.Phys.A,1997,625:621-632.[13]Gu Jianzhong,Wu Xizhen,Zhuo Yizhong,The single-particle spectrum and its spacing and curvature distributions in

  19. Electric monopole transitions from low energy excitations in nuclei

    CERN Document Server

    Wood, J L; De Coster, C; Heyde, Kris L G

    1999-01-01

    Electric monopole (E0) properties are studied across the entire nuclear mass surface. Besides an introductory discussion of various model results (shell model, geometric vibrational and rotational models, algebraic models), we point out that many of the largest E0 transition strengths, $\\rho^2$(E0), are associated with shape mixing. We discuss in detail the manifestation of E0 transitions and present extensive data for~: single-closed shell nuclei, vibrational nuclei, well-deformed nuclei, nuclei that exhibit sudden ground-state changes, and nuclei that exhibit shape coexistence and intruder states. We also give attention to light nuclei, odd-A nuclei, and illustrate a suggested relation between $\\rho^2$(E0) and isotopic shifts.

  20. Collisions of Rare Earth Nuclei - a New Reaction Route for Synthesis of Super Heavy Nuclei

    CERN Document Server

    Choudhury, R K

    2012-01-01

    Theories have predicted an island of stability in the super heavy mass region with half lives ranging from a few seconds to a few thousands of years. Extensive efforts are being made experimentally to reach these nuclei in the region of Z = 110 and above with suitable combinations of proton and neutron numbers. However, the cross sections for production of these nuclei are seen to be in the range of a few pico barns or less, and pose great experimental challenges. We show in the present note that great advantages can be obtained by carrying out heavy ion reactions with suitable combinations of projectile and target nuclei in the rare earth region, that will lead to compound systems with very small excitation energy, and with better neutron/proton ratio for larger stability.

  1. From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds

    Energy Technology Data Exchange (ETDEWEB)

    Theisen, Ch

    2003-01-01

    The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

  2. Recent topics of mesic atoms and mesic nuclei -- $\\phi$ mesic nuclei exist ?--

    CERN Document Server

    Yamagata-Sekihara, J; Cabrera, D; Vacas, M J Vicente

    2008-01-01

    We study $\\phi$-meson production in nuclei to investigate the in-medium modification of the $\\phi$-meson spectral function at finite density. We consider (${\\bar p},\\phi$), ($\\gamma,p$) and ($\\pi^-,n$) reactions to produce a $\\phi$-meson inside the nucleus and evaluate the effects of the medium modifications to reaction cross sections. The structures of the bound states, $\\phi$-mesic nuclei, are also studied. For strong absorptive interaction cases, we need to know the spectrum shape in a wide energy region to deduce the properties of $\\phi$.

  3. KELT-10b: the first transiting exoplanet from the KELT-South survey - a hot sub-Jupiter transiting a V = 10.7 early G-star

    Science.gov (United States)

    Kuhn, Rudolf B.; Rodriguez, Joseph E.; Collins, Karen A.; Lund, Michael B.; Siverd, Robert J.; Colón, Knicole D.; Pepper, Joshua; Stassun, Keivan G.; Cargile, Phillip A.; James, David J.; Penev, Kaloyan; Zhou, George; Bayliss, Daniel; Tan, T. G.; Curtis, Ivan A.; Udry, Stephane; Segransan, Damien; Mawet, Dimitri; Dhital, Saurav; Soutter, Jack; Hart, Rhodes; Carter, Brad; Gaudi, B. Scott; Myers, Gordon; Beatty, Thomas G.; Eastman, Jason D.; Reichart, Daniel E.; Haislip, Joshua B.; Kielkopf, John; Bieryla, Allyson; Latham, David W.; Jensen, Eric L. N.; Oberst, Thomas E.; Stevens, Daniel J.

    2016-07-01

    We report the discovery of KELT-10b, the first transiting exoplanet discovered using the KELT-South telescope. KELT-10b is a highly inflated sub-Jupiter mass planet transiting a relatively bright V = 10.7 star (TYC 8378-64-1), with Teff = 5948 ± 74 K, log g = 4.319_{-0.030}^{+0.020} and [Fe/H] = 0.09_{-0.10}^{+0.11}, an inferred mass M* = 1.112_{-0.061}^{+0.055} M⊙ and radius R* = 1.209_{-0.035}^{+0.047} R⊙. The planet has a radius Rp = 1.399_{-0.049}^{+0.069} RJ and mass Mp = 0.679_{-0.038}^{+0.039} MJ. The planet has an eccentricity consistent with zero and a semimajor axis a = 0.052 50_{-0.000 97}^{+0.000 86} au. The best-fitting linear ephemeris is T0 = 2457 066.720 45 ± 0.000 27 BJDTDB and P = 4.166 2739 ± 0.000 0063 d. This planet joins a group of highly inflated transiting exoplanets with a larger radius and smaller mass than that of Jupiter. The planet, which boasts deep transits of 1.4 per cent, has a relatively high equilibrium temperature of Teq = 1377_{-23}^{+28} K, assuming zero albedo and perfect heat redistribution. KELT-10b receives an estimated insolation of 0.817_{-0.054}^{+0.068} × 109 erg s-1 cm-2, which places it far above the insolation threshold above which hot Jupiters exhibit increasing amounts of radius inflation. Evolutionary analysis of the host star suggests that KELT-10b may not survive beyond the current subgiant phase, depending on the rate of in-spiral of the planet over the next few Gyr. The planet transits a relatively bright star and exhibits the third largest transit depth of all transiting exoplanets with V < 11 in the Southern hemisphere, making it a promising candidate for future atmospheric characterization studies.

  4. Applicability of the {sup 9}Be(d,n){sup 10}B reaction to AB-BNCT skin and deep tumor treatment

    Energy Technology Data Exchange (ETDEWEB)

    Capoulat, M.E., E-mail: capoulat@tandar.cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, CNEA. Av. Gral. Paz 1499 (B1650KNA), San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, M. de Irigoyen 3100 (1650), San Martin, Buenos Aires (Argentina)] [CONICET, Avenida Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina); Minsky, D.M.; Kreiner, A.J. [Gerencia de Investigacion y Aplicaciones, CNEA. Av. Gral. Paz 1499 (B1650KNA), San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, M. de Irigoyen 3100 (1650), San Martin, Buenos Aires (Argentina)] [CONICET, Avenida Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina)

    2011-12-15

    In the range of low bombarding energies (less than about 1.5 MeV) the {sup 9}Be(d,n){sup 10}B reaction produces neutron spectra that can be moderated depending on the choice of the target thickness and the deuteron bombarding energy. In this work, a Monte Carlo simulation study to determine the capability of this reaction to deliver enough dose to efficiently control both skin and deep seated tumors has been performed by means of MCNP calculations using eight optimized {sup 9}Be targets.

  5. Expression of the C-terminal family 22 carbohydrate-binding module of xylanase 10B of Clostridium themocellum in tobacco plant

    OpenAIRE

    Olawole, O.

    2009-01-01

    Carbohydrate-binding modules have been shown to alter plant cell wall structural architecture. Hence, they have the potential application of being used to engineer the plant to produce tailor-made natural fibers in the cell wall. The Clostridium thermocellum xylanase, Xyn10B, contains two CBMs that belong to family 22 (CBM22). The C-terminal CBM22-2 of the glycoside hydrolase (GH) 10 had been characterized to interact with xylan, a major hemicellulosic component in the secondary cell wall of ...

  6. Studies of exotic nuclei; Etudes des noyaux exotiques

    Energy Technology Data Exchange (ETDEWEB)

    Angelique, J.C.; Orr, N.A. [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); Collaboratio: CATANE (Italy), DAPNIA-Saclay, CSNSM-Orsay, GANIL-Caen, IPN-Orsay, NSCL-MSU (USA), Los Alamos (USA), University of Manchester (United Kingdom), University of Surrey (United Kingdom), FLNR JINR Dubna (Russia), IAP-Bucharest (Romania), NPI-Rez (Czech Republic), CCLRLC-Daresbury (United Kingdom)

    1997-12-31

    The study of the nuclei far off stability valley is of much interest for testing the nuclear models established for the stable nuclei but also for astrophysics to understand the nucleosynthesis. Experiments aim to measure the mass and lifetime, to build the decay schemes and also to study the structure and the properties of these nuclei. The radioactive beam group focused its research on light neutron-rich nuclei having a halo neutron structure. Mass measurements in N {approx} Z nuclei namely in A {approx} 60-80 proton-rich nuclei, important for understanding the rp process, are mentioned, as well as in nuclei in the {sup 100}Sn region. In the newly obtained {sup 26}O and {sup 28}O nuclei the lifetimes, the probabilities of emission of one for more neutrons were determined. The data analysis has permitted to determine also for the first time the lifetimes of {sup 27,29}F and {sup 30}Ne. Studies of nuclei in the {sup 100}Sn region, near the proton drip line in the ground and isomeric states are now under way. The spectroscopy (energy levels, gamma emissions, etc.) of the neutron-rich nuclei produced by the {sup 36}S fragmentation has been carried out in {sup 31}Ne, {sup 17}B and {sup 29}F. Studies by Coulomb excitation of the 2{sup +} excited states and associated probability B (E2) in O, Ne, Ni and Zn are now analysed 6 refs.

  7. Effective field theory description of halo nuclei

    Science.gov (United States)

    Hammer, H.-W.; Ji, C.; Phillips, D. R.

    2017-10-01

    Nuclear halos emerge as new degrees of freedom near the neutron and proton driplines. They consist of a core and one or a few nucleons which spend most of their time in the classically-forbidden region outside the range of the interaction. Individual nucleons inside the core are thus unresolved in the halo configuration, and the low-energy effective interactions are short-range forces between the core and the valence nucleons. Similar phenomena occur in clusters of 4He atoms, cold atomic gases near a Feshbach resonance, and some exotic hadrons. In these weakly-bound quantum systems universal scaling laws for s-wave binding emerge that are independent of the details of the interaction. Effective field theory (EFT) exposes these correlations and permits the calculation of non-universal corrections to them due to short-distance effects, as well as the extension of these ideas to systems involving the Coulomb interaction and/or binding in higher angular-momentum channels. Halo nuclei exhibit all these features. Halo EFT, the EFT for halo nuclei, has been used to compute the properties of single-neutron, two-neutron, and single-proton halos of s-wave and p-wave type. This review summarizes these results for halo binding energies, radii, Coulomb dissociation, and radiative capture, as well as the connection of these properties to scattering parameters, thereby elucidating the universal correlations between all these observables. We also discuss how Halo EFT's encoding of the long-distance physics of halo nuclei can be used to check and extend ab initio calculations that include detailed modeling of their short-distance dynamics.

  8. Nuclei at extreme conditions. A relativistic study

    Energy Technology Data Exchange (ETDEWEB)

    Afanasjev, Anatoli [Mississippi State Univ., Mississippi State, MS (United States)

    2014-11-14

    The major goals of the current project were further development of covariant density functional theory (CDFT), better understanding of its features, its application to different nuclear structure and nuclear astrophysics phenomena and training of graduate and undergraduate students. The investigations have proceeded in a number of directions which are discussed in detail in the part “Accomplishments” of this report. We have studied the role of isovector and isoscalar proton-neutron pairings in rotating nuclei; based on available experimental data it was concluded that there are no evidences for the existence of isoscalar proton-neutron pairing. Generalized theoretical approach has been developed for pycnonuclear reaction rates in the crust of neutron stars and interior of white dwarfs. Using this approach, extensive database for considerable number of pycnonuclear reactions involving stable and neutron-rich light nuclei has been created; it can be used in future for the study of various nuclear burning phenomena in different environments. Time-odd mean fields and their manifestations in terminating states, non-rotating and rotating nuclei have been studied in the framework of covariant density functional theory. Contrary to non-relativistic density functional theories these fields, which are important for a proper description of nuclear systems with broken time-reversal symmetry, are uniquely defined in the CDFT framework. Hyperdeformed nuclear shapes (with semi-axis ratio 2.5:1 and larger) have been studied in the Z = 40-58 part of nuclear chart. We strongly believe that such shapes could be studied experimentally in the future with full scale GRETA detector.

  9. Modello per una sistematica dei nuclei stabili

    Directory of Open Access Journals (Sweden)

    Medi Enrico

    1960-06-01

    Full Text Available Mediante una espressione lineare e tre successioni di numeri semplici
    è possibile ricostruire, nella quasi totalità, la serie dei nuclei degli elementi
    stabili. È cioè possibile conoscere il numero dei protoni (e quindi dei
    neutroni che entrano a far parte del nucleo di un elemento stabile,
    quando sia dato il numero di massa di esso.
    Il metodo è dedotto da un modello di nucleo a particelle alfa, secondo
    uno schema di simmetria di tipo cristallino, inteso ovviamente
    in senso topologico.

  10. Effective field theory for deformed atomic nuclei

    Science.gov (United States)

    Papenbrock, T.; Weidenmüller, H. A.

    2016-05-01

    We present an effective field theory (EFT) for a model-independent description of deformed atomic nuclei. In leading order this approach recovers the well-known results from the collective model by Bohr and Mottelson. When higher-order corrections are computed, the EFT accounts for finer details such as the variation of the moment of inertia with the band head and the small magnitudes of interband E2 transitions. For rotational bands with a finite spin of the band head, the EFT is equivalent to the theory of a charged particle on the sphere subject to a magnetic monopole field.

  11. Algebraic description of intrinsic modes in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. (Los Alamos National Lab., NM (USA))

    1990-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intrinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. (author).

  12. Algebraic description of intrinsic modes in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.

    1989-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. 28 refs., 1 fig.

  13. Experimental level densities of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Guttormsen, M.; Bello Garrote, F.L.; Eriksen, T.K.; Giacoppo, F.; Goergen, A.; Hagen, T.W.; Klintefjord, M.; Larsen, A.C.; Nyhus, H.T.; Renstroem, T.; Rose, S.J.; Sahin, E.; Siem, S.; Tornyi, T.G.; Tveten, G.M. [University of Oslo, Department of Physics, Oslo (Norway); Aiche, M.; Ducasse, Q.; Jurado, B. [University of Bordeaux, CENBG, CNRS/IN2P3, B.P. 120, Gradignan (France); Bernstein, L.A.; Bleuel, D.L. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Byun, Y.; Voinov, A. [Ohio University, Department of Physics and Astronomy, Athens, Ohio (United States); Gunsing, F. [CEA Saclay, DSM/Irfu/SPhN, Cedex (France); Lebois, L.; Leniau, B.; Wilson, J. [Institut de Physique Nucleaire d' Orsay, Orsay Cedex (France); Wiedeking, M. [iThemba LABS, P.O. Box 722, Somerset West (South Africa)

    2015-12-15

    It is almost 80 years since Hans Bethe described the level density as a non-interacting gas of protons and neutrons. In all these years, experimental data were interpreted within this picture of a fermionic gas. However, the renewed interest of measuring level density using various techniques calls for a revision of this description. In particular, the wealth of nuclear level densities measured with the Oslo method favors the constant-temperature level density over the Fermi-gas picture. From the basis of experimental data, we demonstrate that nuclei exhibit a constant-temperature level density behavior for all mass regions and at least up to the neutron threshold. (orig.)

  14. Fusion and reactions of exotic nuclei

    Directory of Open Access Journals (Sweden)

    Sánchez-Benítez A.M.

    2011-10-01

    Full Text Available Close to the drip lines, the scattering cross sections of halo nuclei show a different behaviour as compared to the tightly bound projectiles of the stability line. Several experiments carried out in the last decade have been dedicated to investigate the competition between transfer, breakup and fusion channels at energies around and below the Coulomb barrier. The rather complex scenario gives rise to conflicting conclusions concerning the effect of breakup and transfer on reaction dynamics and the sub-barrier fusion process. In this work we discuss recent experimental findings in fusion and reactions of 6He halo nucleus at energies around the Coulomb barrier.

  15. Effective field theory for deformed atomic nuclei

    CERN Document Server

    Papenbrock, T

    2015-01-01

    We present an effective field theory (EFT) for a model-independent description of deformed atomic nuclei. In leading order this approach recovers the well-known results from the collective model by Bohr and Mottelson. When higher-order corrections are computed, the EFT accounts for finer details such as the variation of the moment of inertia with the band head and the small magnitudes of interband $E2$ transitions. For rotational bands with a finite spin of the band head, the EFT is equivalent to the theory of a charged particle on the sphere subject to a magnetic monopole field.

  16. Short-Distance Structure of Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Douglas Higinbotham, Eliazer Piasetzky, Stephen Wood

    2011-06-01

    One of Jefferson Lab's original missions was to further our understanding of the short-distance structure of nuclei. In particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions; a phenomena commonly referred to as short-range correlations. Herein, we review the results of the (e,e'), (e,e'p) and (e,e'pN) reactions that have been used at Jefferson Lab to probe this short-distance structure as well as provide an outlook for future experiments.

  17. Coherent Pions From Neutrino Scattering Off Nuclei

    CERN Document Server

    Valverde, M; Hernandez, E; Nieves, J; Vacas, M J Vicente

    2010-01-01

    We describe a model for pion production off nucleons and coherent pions from nuclei induced by neutrinos in the 1 GeV energy regime. Besides the dominant Delta pole contribution, it takes into account the effect of background terms required by chiral symmetry. Moreover, the model uses a reduced nucleon-to-Delta resonance axial coupling, which leads to coherent pion production cross sections around a factor two smaller than most of the previous theoretical estimates. Nuclear effects like medium corrections on the Delta propagator and final pion distortion are included.

  18. Inclusive inelastic electron scattering from nuclei

    CERN Document Server

    Fomin, Nadia

    2007-01-01

    Inclusive electron scattering from nuclei at large x and $Q^2$ is the result of a reaction mechanism that includes both quasi--elastic scattering from nucleons and deep inelastic scattering from the quark constituents of the nucleons. Data in this regime can be used to study a wide variety of topics, including the extraction of nuclear momentum distributions, the influence of final state interactions and the approach to $y$-scaling, the strength of nucleon-nucleon correlations, and the approach to $x$- scaling, to name a few. Selected results from the recent experiment E02-019 at the Thomas Jefferson National Accelerator Facility will be shown and their relevance discussed.

  19. Superheavy nuclei – cold synthesis and structure

    Indian Academy of Sciences (India)

    Raj K Gupta

    2001-08-01

    The quantum mechanical fragmentation theory (QMFT), given for the cold synthesis of new and superheavy elements, is reviewed and the use of radioactive nuclear beams (RNB) and targets (RNT) is discussed. The QMFT is a complete theory of cold nuclear phenomena, namely, the cold fission, cold fusion and cluster radioactivity. Also, the structure calculations based on the axially deformed relativistic mean field (DRMF) approach are presented which predict new regions of spherical magicity, namely = 120 and = 172 or 184, for superheavy nuclei. This result is discussed in the light of recent experiments reporting the cold synthesis of = 118 element.

  20. Cosmic rays from active galactic nuclei

    CERN Document Server

    Berezhko, E G

    2008-01-01

    Cosmic ray (CR) acceleration at the shock created by the expanding cocoons around active galactic nuclei (AGNs) is studied. It is shown that above the energy $10^{18}$ eV the overall energy spectrum of CRs, produced during the AGN evolution and released in the intergalactic space, has the form $N\\propto \\epsilon^{-\\gamma}$, with $\\gamma\\approx 2.6$, which extends up to $\\epsilon_{max}\\sim 10^{20}$ eV. It is concluded that cocoons shocks have to be considered as a main source of extragalactic CRs, which together with Galactic supernova remnants provide the observed CR spectrum.