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Sample records for 6li 7li 9be

  1. $\\Sigma^- p$ 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.

  2. Global optical model potentials for symmetrical lithium systems: 6Li+6Li, 7Li+7Li at Elab = 5-40 MeV

    International Nuclear Information System (INIS)

    Angular distributions of 6Li+6Li elastic scattering were measured for Elab=5-40 MeV. An optical model analysis of these data together with older data of 7Li+7Li elastic scattering taken at Elab = 8-17 MeV was performed with the aim to search for a ''global'' OM potential which describes elastic scattering in both Li-Li systems in a broad energy range. Both surface and volume absorbing potentials can be found which fulfill this requirement if a linear energy dependence is assumed of the depths of the real as well as the imaginary potential. These depths, if fitted to individual angular distributions, are found to vary in a correlated manner with the beam energy. This is taken as indication of strong coupling between elastic, inelastic, and reaction channels. This is corroborated by the existence of resonances in reaction channels at these energies where the potential depths are most pronouncedly changing. (orig.)

  3. Asymptotic and near-target direct breakup of 6Li and 7Li

    Science.gov (United States)

    Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

    2016-04-01

    Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

  4. 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

  5. Study of the reactions 6Li(pα)3He, 6Li(dα)4He, 6Li(dp0)7Li and 6Li(dp1)7Li* from 300 keV to 1000 keV

    International Nuclear Information System (INIS)

    Experimental results are presented for the four reactions 6Li (pα)3He, 6Li (dα)4He, 6Li (dp0)7Li and 6Li (dp1)7Li* between 300 keV and 1000 keV. The angular distributions, the excitation curves and the total cross-section curves are presented in absolute values. (authors)

  6. THE NEW DETECTIONS OF 7Li/6Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

    International Nuclear Information System (INIS)

    We have determined the isotopic abundance ratio of 7Li/6Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7Li/6Li = 8.1+3.6-1.8 and 6.3+3.0-1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7Li/6Li = 7.1+2.9-1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

  7. 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 (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.

  8. Space distributions and decay probability for excited state of 7Li*(7,45 MeV) in reaction 7Li(alpha, alpha6Li)n

    International Nuclear Information System (INIS)

    Differential cross-sections of excitation and decay of 7Li*(7,45 MeV) resonance into 6Li + n channel in three particle reaction 7Li(alpha, alpha6Li)n at alpha-particle energy of 27,2 MeV have been determined in kinematically complete and incomplete experiments. Usage of position sensitive detector made it possible to obtain the data on space distributions of decay events for full range of possible angles and to determine the total probability of this process, which value essentially differs from the data for binary reactions. This result is agreed with previously obtained [1] and confirms the theoretical calculations [2] of decay branching ratio for short lived near-threshold resonances in three particle reactions

  9. 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...

  10. Study of the reactions 9Be(p, α)6Li, 9Be(p,d)8Be from 300 keV to 900 keV

    International Nuclear Information System (INIS)

    The experimental results concerning the two reactions 9Be(p,α)6Li and 9Be(p,d)8Be from 300 to 900 keV are presented. The angular distribution, excitation and total cross-section curves are expressed in absolute values after a normalization carried out using results given by Weber, Davis and Marion. (authors)

  11. 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.

  12. Threshold behavior of interaction potential for the system 7Li + 64Ni: Comparison with 6Li + 64Ni

    Science.gov (United States)

    Shaikh, Md. Moin; Das, Mili; Roy, Subinit; Sinha, M.; Pradhan, M. K.; Basu, P.; Datta, U.; Ramachandran, K.; Shrivastava, A.

    2016-09-01

    The elastic scattering angular distributions for the system 7Li + 64Ni were measured in the bombarding energy range of 12 MeV ≤Elab ≤ 26.4 MeV. A phenomenological optical model analysis was performed for the measured data. The strengths of the fitted potential components at the surface were estimated to extract their variation with energy. Further analyses of the measured angular distributions were performed with a hybrid potential composed of a renormalized folded real and a phenomenological imaginary potential. Both the model potentials predict similar energy dependent behavior for the effective interaction potential around the barrier. Unlike the heavy targets, 7Li + 64Ni does not show a normal threshold behavior. It also does not clearly exhibit a behavior similar to 6Li + 64Ni. The real potential for 7Li + 64Ni does not exhibit any significant energy dependence and the imaginary potential strength remains almost independent of energy above the Coulomb barrier (∼ 14 MeV). However, at energies below the barrier, a sudden drop in the imaginary potential strength is observed.

  13. The 9Be(p,α)6Li and 9Be(p,d)8Be cross sections at low energies

    International Nuclear Information System (INIS)

    Data for the 9Be(p,α)6Li and 9Be(p,d)8Be reactions with proton energies up to 700 keV are fitted using R-matrix formulae. The data include values of the astrophysical S factors and of the angular-distribution and analysing-power coefficients. A reasonable fit is obtained with two 1- and two 2+ levels of 10B, and one each of 2-, 1+ and 3+ levels. All represent levels outside the energy range fitted except for a 1- level at 6.87 MeV and a 2+ level at 6.95 MeV

  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. HOTSPUR progress report: neutron source spectrum characterization, and 6Li(n,xα) and 7Li(n,xα) cross section determination

    International Nuclear Information System (INIS)

    As a prerequisite to high accuracy measurements involving the bulk configuration of 6LiD we must have a good grasp of the details of the RTNS-I neutron source energy spectrum. Experiments to this end involving neutron yield vs deuteron energy, ratios of foil activation of selected elements, and pulse height distributions of a Si surface barrier detector are described. With this knowledge, the 4He-production cross sections for 6Li and 7Li are found experimentally to be 0.512b and 0.336b, respectively, at anti E/sub N/ = 15.0 MeV in free-field geometry. 14 references

  16. Excitation and decay of 7Li*(4.63) → α + t in the 7Li(αα1)7Li(4.63) and 9Be(dα1)7Li(4.63) reactions in close kinematic conditions

    International Nuclear Information System (INIS)

    Angular correlation function (ACF) of alpha particles and tritons from 7Li* (4.63) decay in the d+9Be → α1+7Li*(4.63) → α1+t+α reaction at deuteron energy Ed=13.6 MeV for escape angles Θαlab=45 and 67 deg has been measured. Results of investigation into the α+7Li → α1+7Li*(4.63) → α1+t+d reaction at Eα=27.2 MeV, Θα1lab=30 deg have been used as well. Kinematic conditions for outlet channels of both reactions are identical. An analytical expression for ACF has been derived. The analysis shows that different mechanisms of the first stage of the d+9Be and α+7Li reactions result in differential phase shifts and limits of summing in the formula for ACF and, therefore, in different ACF form

  17. 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)

  18. Interaction of loosely bound radioactive {sup 7}Be and stable {sup 7}Li with {sup 9}Be

    Energy Technology Data Exchange (ETDEWEB)

    Verma, S.; Mandal, S.; Ranjit,; Datta, S.K.; Singh, R. [University of Delhi, Department of Physics and Astrophysics, Delhi (India); Das, J.J.; Jhingan, A.; Golda, K.S.; Madhavan, N.; Sugathan, P.; Nath, S.; Varughese, T.; Gehlot, J. [Inter University Accelerator Centre, New Delhi (India); Kalita, K.; Barua, S. [Gauhati University, Department of Physics, Guwahati (India); Sahu, P.K.; John, B.; Nayak, B.K.; Jha, V.; Saxena, A. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India)

    2010-06-15

    Quasielastic scattering angular distributions have been measured for the {sup 7}Be+{sup 9}Be system at E{sub lab} = 17, 19 and 21MeV in the angular range {theta}{sub cm}=24 - 57 . An optical model (OM) analysis of these data has been carried out in order to extract optical potential parameters and reaction cross-sections. One-proton stripping cross-sections were also measured for this system at E{sub lab} = 19 and 21MeV. These transfer angular-distribution data were compared with the finite-range distorted-wave Born approximation (FRDWBA) calculations. For the {sup 7}Li+{sup 9}Be system quasielastic scattering angular distributions were measured and emitted light charged particles were detected at E{sub lab} = 15.75, 24.00 and 30.00MeV in the angular range {theta}{sub cm} = 7 - 70 . Fusion cross-sections were obtained by reproducing the measured {alpha} -evaporation spectra from the compound nucleus at backward angles with the statistical model calculations. The ratios of the experimental fusion cross-sections to the total reaction cross-sections (obtained from OM analysis) were found to be small. This result suggests that the break-up process has a strong influence on the fusion process leading to a reduction in the fusion cross-section. (orig.)

  19. Lithium isotope separation by 6Li/7Li countercurrent exchange between lithium-amalgam and aqueous LiOH in a spray column

    International Nuclear Information System (INIS)

    Lithium isotope separation by 6Li/7Li exchange between lithium-amalgam and aqueous LiOH has been investigated by using a column consisting of a vertical Pyrex glass tube in which aqueous LiOH flows up and a fine spray of lithium-amalgam falls down. As the number of theoretical plates, a value of 48 was obtained on a single column while the amalgam stability was η = 0.74, where η is the ratio between Li concentration in amalgam at the column bottom and that at the column top. That is, a large separation may be obtained in a single column in spite of amalgam decomposition which takes place as a side reaction. (author)

  20. TL response of pairs of 6LiF:Mg,Cu,Si/7LiF:Mg,Cu,Si and TLD-600/TLD-700 to 0.1–12 MeV neutrons

    International Nuclear Information System (INIS)

    Neutron dosimetery continues to remain an important and a challenging aspect of radiation protection due to the higher biological effectiveness of neutrons than that of gamma rays and the intricacy in the responses of the detectors. The need for personal dosimetry in mixed fields of neutrons and gamma rays has considerably increased due to the rising number of nuclear facilities, nuclear power plants, medical therapy equipment, accelerators and so on. The most widely used technique for personal dosimetry has been the albedo technique employing pairs of neutron sensitive 6LiF:Mg,Ti (TLD-600) and neutron insensitive 7LiF:Mg,Ti (TLD-700) thermoluminescent dosimeters (TLDs). Off late, LiF:Mg,Cu,Si has emerged as one of the most promising TLD material, having the advantages of high sensitivity, near tissue equivalence to gamma rays, negligible fading on pre and post-irradiation storage, thermal stability for readout and negligible residual signal after the readout. In this study, neutron energy response of indigenously developed 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLD pairs was evaluated to neutrons of energy from thermal to 11.6 MeV and was compared with the response of TLD-600 and TLD-700 pairs. The net TL per unit neutron dose for the 6LiF:Mg,Cu,Si/7LiF:Mg,Cu,Si TLD pair was found to be about 10 times of that of the TLD-600/TLD-700 pair. Unlike, TLD-600 and TLD-700, the glow curve structure of 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si remained almost the same for all the irradiations. Thus, 6LiF:Mg,Cu,Si and 7LiF:Mg,Cu,Si TLDs provided a better alternate to TLD-600 and TLD-700 for the dosimetry of mixed fields of neutrons and gamma rays. -- Highlights: ► High sensitivity 6Li and 7Li enriched LiF:Mg,Cu,Si TLDs have been developed at KAERI, Korea. ► Main TL glow peak remains unchanged for 6Li and 7Li enrichment and radiation type. ► Net TL/mSv is about 10 times of that of TLD-600/TLD-700 pairs

  1. Production cross section of At radionuclides from $^{7}$Li+$^{\\textrm{nat}}$Pb and $^{9}$Be+$^{\\textrm{nat}}$Tl reactions

    CERN Document Server

    Maiti, Moumita

    2011-01-01

    Earlier we reported theoretical studies on the probable production of astatine radionuclides from $^{6,7}$Li and $^{9}$Be-induced reactions on natural lead and thalliun targets, respectively. For the first time, in this report, production of astatine radionuclides has been investigated experimentally with two heavy ion induced reactions: $^{9}$Be+$^{\\textrm{nat}}$Tl and $^{7}$Li+$^{\\textrm{nat}}$Pb. Formation cross sections of the evaporation residues, $^{207,208,209,210}$At, produced in (HI, xn) channel, have been measured by the stacked-foil technique followed by the off-line $\\gamma$-spectrometry at the low incident energies ($<$50 MeV). Measured excitation functions have been explained in terms of compound nuclear reaction mechanism using Weisskopf-Ewing and Hauser-Feshbach model. Absolute cross section values are lower than the respective theoretical predictions.

  2. The {sup 9}Be(p,p{sub 0}){sup 9}Be, {sup 9}Be(p,d{sub 0}){sup 8}Be, and {sup 9}Be(p,α{sub 0}){sup 6}Li cross-sections for analytical purposes

    Energy Technology Data Exchange (ETDEWEB)

    Krat, S. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe Road 31, Moscow 115409 (Russian Federation); Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Mayer, M. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Porosnicu, C. [National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, Magurele, Jud Ilfov, 077125 Bucharest (Romania)

    2015-09-01

    The cross-sections for the {sup 9}Be(p,d{sub 0}){sup 8}Be nuclear reaction and for {sup 9}Be(p,p{sub 0}){sup 9}Be backscattering were measured at a laboratory scattering angle of 165° in the energy range from 400 to 4150 keV, the cross-section for the {sup 9}Be(p,α{sub 0}){sup 6}Li nuclear reaction was determined in the energy range from 400 to 1300 keV. The cross-sections were determined using thin films. The absolute accuracies are about 4.4–8.6% for the backscattering, 4.6–24% for the {sup 9}Be(p,d{sub 0}){sup 8}Be nuclear reaction, and 4.5–5% for the {sup 9}Be(p,α{sub 0}){sup 6}Li nuclear reaction cross-section. The derived cross-section data were benchmarked in the energy range 1100–4100 keV by comparison to measured spectra from bulk beryllium. The cross-section data are presented in graphical and tabular forms.

  3. Astrophysical Impact of the Updated 9Be(p,α)6Li and 10B(p,α)7Be Reaction Rates As Deduced By THM

    Science.gov (United States)

    Lamia, L.; Spitaleri, C.; Tognelli, E.; Degl'Innocenti, S.; Pizzone, R. G.; Prada Moroni, P. G.

    2015-10-01

    The complete understanding of the stellar abundances of lithium, beryllium, and boron represents one of the most interesting open problems in astrophysics. These elements are largely used to probe stellar structure and mixing phenomena in different astrophysical scenarios, such as pre-main-sequence or main-sequence stars. Their different fragility against (p,α) burning reactions allows one to investigate different depths of the stellar interior. Such fusion mechanisms are triggered at temperatures between T ≈ (2-5) × {10}6 K, thus defining a corresponding Gamow energy between ≈ 3-10 keV, where S(E)-factor measurements need to be performed to get reliable reaction rate evaluations. The Trojan Horse Method is a well defined procedure to measure cross sections at Gamow energies overcoming the uncertainties due to low-energy S(E)-factor extrapolation as well as electron screening effects. Taking advantage of the {\\mathtt{THM}} measure of the 9Be(p,α)6Li and 10B(p,α)7Be cross sections, the corresponding reaction rates have been calculated and compared with the evaluations by the NACRE collaboration, widely used in the literature. The impact on surface abundances of the updated 9Be and 10B (p,α) burning rates is discussed for pre-MS stars.

  4. 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.

  5. Evidence of Cluster Structure of $^9$Be from $^3$He+$^9$Be Reaction

    CERN Document Server

    Lukyanov, S M; Naumenko, M A; Xu, Yi; Trzaska, W H; Burjan, V; Kroha, V; Mrazek, J; Glagolev, V; Piskoř, Š; Voskoboynik, E I; Khlebnikov, S V; Penionzhkevich, Yu E; Skobelev, N K; Sobolev, Yu G; Tyurin, G P; Kuterbekov, K; Tuleushev, Yu

    2015-01-01

    The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a $^{9}$Be target with a $^3$He beam at an incident energy of 30 MeV. Angular distributions for $^9$Be($^3$He,$^3$He)$^{9}$Be, $^9$Be($^3$He,$^4$He)$^{8}$Be, $^9$Be($^3$He,$^5$He)$^{7}$Be, $^9$Be($^3$He,$^6$Li)$^6$Li and $^9$Be($^3$He,$^5$Li)$^7$Li reaction channels were measured. Experimental angular distributions for the corresponding ground states (g.s.) were analysed within the framework of the optical model, the coupled-channel approach and the distorted-wave Born approximation. Cross sections for channels leading to unbound $^5$He$_{g.s.}$, $^5$Li$_{g.s.}$ and $^8$Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile is constrained by two-body kinematics. Information on the cluster structure of $^{9}$Be was obtained from the transfer channels. It was concluded that cluster transfer is an important mechanism in t...

  6. Observations of 6Li in Galactic Stars

    Science.gov (United States)

    Hobbs, L. M.

    2000-05-01

    Several important goals have motivated observationally challenging attempts to measure 6Li/7Li isotopic ratios and, hence, 6Li abundances in stars. In particular, a general understanding, based on cosmic-ray spallation reactions, of the nucleosynthetic origins of the very low Galactic abundances of 6Li, Be, and B has followed from measurements of both the relative and the absolute abundances of these various, related isotopes. In the cases of Be and B, such data are currently available for 20 or more stars that span a wide range of metallicity, i.e. age. In contrast, nuclear burning of the very fragile 6Li nuclei during stellar contraction to the main sequence generally reduces the surface abundance of this lighter isotope below the observable limit. A few relatively nearby stars of low metallicity which are found close to the Population II main-sequence turnoff during later hydrogen burning seem to constitute the observable exceptions. Spectra of very high quality, typically with R > 100,000 and S/N > 400 at V > 9.0, are needed to reveal the small extra asymmetry and the small extra width that are introduced into the profile of the isotopically blended Li I 6707 A line by the small fractions of 6Li detected so far. Precise measurements of (or, in all but a few cases, uppper limits on) the 6Li/7Li ratio are now available for almost 30 stars. At a ratio 6Li/7Li = 0.06, the first positive detection of stellar 6Li was achieved in 1993 for the turnoff halo star HD 84937, by Smith, Lambert, & Nissen. Probable detections of the lighter isotope at generally similar isotopic ratios have since been reported for four additional metal-poor stars. The imminent availability of more telescopes in the 8m to 10m class promises a rewarding extension of this effort to a relatively large number of excellent, fainter 6Li candidates.

  7. Angular correlations and decay branching ratio for excited state of 7Li*(7,45 MeV) in reactions 7Li(alpha, alpha)7Li*

    International Nuclear Information System (INIS)

    Measurements of differential cross-sections of alpha-particle inelastic scattering by 7Li nuclei and 7Li(alpha, alpha 6Li)n, 7Li(alpha, alpha alpha)t reactions have been performed at the energy Ea = 27,2 MeV. Probability of 7Li*(7,45 MeV) decay into 6Li + n channel has been determined from the ratio of cross-sections measured in kinematically complete and incomplete experiments. The large discrepancy of this value (P 0,49 ± 0,06) and of those obtained at the study of 7Li*(7,45 MeV) decay in binary reactions can be explained by the influence of Coulomb field of accompanied alpha-particle on the decay of near-threshold resonances in three-particle reactions

  8. 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.

  9. Systematic model-dependent behaviour of fusion involving weakly bound projectiles 6,7Li

    International Nuclear Information System (INIS)

    Many measurements on complete fusion (CF) cross section at above barrier energies involving weakly bound stable projectiles (e.g., 6Li, 7Li and 9Be) show suppression by various degrees compared to theoretical estimates as well as experimental CF cross sections of reactions involving strongly bound projectiles. However, there is no concrete picture at sub-barrier energies. The conclusions based on coupled-channels (CC) calculations using different codes (e.g., FRESCO or CCFULL) may differ as the theoretical models used to calculate fusion are not same. In a recent paper on complete fusion in 7Li+152Sm system, the fusion cross sections calculated by CCFULL and FRESCO have been shown to be different despite using same bare potential. It was observed that with the inclusion of only inelastic couplings, the results of FRESCO were much closer to the experimental data in the above barrier region, while the CCFULL results overpredict the data over the entire range. To explore the above observation in different systems involving 6,7Li as projectile, in the present work, a systematic and detailed study has been carried out by means of CC calculations using both FRESCO and CCFULL. The aim is to analyze the differences between the two models of calculations

  10. 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.

  11. 6Li detection in metal-poor stars: can 3D model atmospheres solve the second lithium problem?

    CERN Document Server

    Steffen, M; Caffau, E; Bonifacio, P; Ludwig, H -G; Spite, M

    2012-01-01

    The presence of 6Li in the atmospheres of metal-poor halo stars is usually inferred from the detection of a subtle extra depression in the red wing of the 7Li doublet line at 670.8 nm. However, the intrinsic line asymmetry caused by convective flows in the photospheres of cool stars is almost indistinguishable from the asymmetry produced by a weak 6Li blend on a (presumed) symmetric 7Li profile. Previous determinations of the 6Li/ 7Li isotopic ratio based on 1D model atmospheres, ignoring the convection-induced line asymmetry, must therefore be considered as upper limits. By comparing synthetic 1D LTE and 3D non-LTE line profiles of the Li 670.8 nm feature, we quantify the differential effect of the convective line asymmetry on the derived 6Li abundance as a function of effective temperature, gravity, and metallicity. As expected, we find that the asymmetry effect systematically reduces the resulting 6Li/7Li ratios. Depending on the stellar parameters, the 3D-1D offset in 6Li/7Li ranges between -0.005 and -0....

  12. Electric dipolarizability of 7Li

    Indian Academy of Sciences (India)

    Sudhir R Jain; Arun K Jain; S Kailas

    2008-12-01

    We calculate the electric dipolarizability of 7Li nucleus within the cluster model and estimate a value of about 0.0188 fm3. We also discuss the possibility of observing this in the scattering of 7Li from a 208Pb target at energies about 30 MeV.

  13. Deformation Effects in 6Li

    International Nuclear Information System (INIS)

    The asymptotic D - to S -state ratio η for the 6Li> bound-state overlap is determined from measurements of the tensor analyzing powers for (6Li,d ) reactions on medium-heavy targets. The reactions are described by the distorted-wave Born approximation assuming a direct α -particle transfer reaction mechanism. The calculations provide good agreement with cross section and vector analyzing power data. A best fit to the tensor analyzing power data results in a new value of η=+0.0003±0.0009 , much smaller than previous experimental and theoretical determinations. copyright 1998 The American Physical Society

  14. Global optical-model potentials for the elastic scattering of sup(6,7)Li projectiles

    International Nuclear Information System (INIS)

    Simultaneous fits have been made to 44 6Li data sets covering the mass range 24-208 and the energy range 13-156 MeV in order to determine an average ('global') optical-model potential for 6Li scattering. A similar study has been made for 25 7Li data sets over the same mass range and an energy range of 28-88 MeV to find an average 7Li potential. With Saxon-Woods factors, constant values may be used for all parameters except for the depth of the imaginary potential which decreases in magnitude with increasing mass. The necessity of energy dependence, Coulomb correction and (for 7Li) a symmetry term is investigated. The variation of the integral properties of the potentials is discussed, and also a comparison is made for the two projectiles. Application of the global potentials is made to inelastic scattering and single-nucleon transfer reactions. (orig.)

  15. Lines in the spectrum of 7LiH (4728--5298 A)

    International Nuclear Information System (INIS)

    The emission spectra of the A1Σ+--X1Σ+ bands of 7LiH were photographed in the 4728A - 5298 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High purity 7LiH crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 7Li in 7LiH and 7LiD was 99.93 percent. The discharge source was a demountable stainless steel hollow cathode lamp. The lithium hydride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of H2. The discharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 7LiH are given in this repot 9COO-2326-19). Similar spectra for 6LiH and 6LiD are given in companion reports (COO-2326-17) and (COO-2326-18), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  16. Lamb shifts and hyperfine structure in 6Li+ and 7Li+: Theory and experiment

    DEFF Research Database (Denmark)

    Riis, E.; Sinclair, A. G.; Poulsen, Ove;

    1994-01-01

    states, using newly calculated values for the magnetic dipole and electric quadrupole coupling constants, and the hyperfine shifts subtracted from the measurements. The resulting transition frequencies are then analysed on three different levels. First, the isotope shifts in the fine-structure splittings......High-precision laser-resonance measurements accurate to +/-0.5 MHz, or better are reported for transitions among the 1s2s S-3(1)-1s2p P-3(J) hyperfine manifolds for each of J = 0, 1, and 2 in both Li-6(+) and Li-7(+). A detailed analysis of hyperfine structure is performed for both the S and P...

  17. Lines in the spectrum of 6LiH (2985--5158 A)

    International Nuclear Information System (INIS)

    The emission spectra of the A1Σ+--X1Σ+ bands of 6LiH were photographed in the 2985 - 5158 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High-purity 6LiH crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 6Li in 6LiH was 95.58 percent. The discharge source was a demountable stainless steel hollow cathode lamp. The lithium hydride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of H2. The disharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 6LiH are given in this report (COO-2326-17). Similar spectra for 6LiD and 7LiH are given in companion reports (COO-2326-18) and (COO-2326-19), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  18. Lines in the spectrum of 6LiD (3086--5156 A)

    International Nuclear Information System (INIS)

    The emission spectra of A1Σ+--X1Σ+ bands of 6LiD were photographed in the 3086 A - 5156 A region with a 3.4 meter Ebert Spectrograph of theoretical resolution of about 0.07 cm-1. High-purity 6LiD crystals were obtained from Oak Ridge National Laboratory. The atomic percent of 6Li in 6LiD was 95.58 percent. The discharge source is a demountable stainless steel hollow cathode lamp. The lithium deuteride crystals were packed into the cathode. Pressure in the discharge tube was about 10 to 20 torr of D2. The discharge was run at about 600 volts and 1.25 to 1.75 amperes. Acceptable spectra were obtained with exposure time of 6 hours. A Westinghouse iron hollow cathode was used to produce the iron spectrum for calibration. The plates were measured on the Gaertner photoplate comparator with an encoder system and on-line computer service at Argonne National Laboratory. The measured lines in the spectra of 6LiD are given in this report (COO-2326-18). Similar spectra for 6LiH and 7LiH are given in companion reports (COO-2326-17) and (COO-2326-19), respectively. The relative intensities of the lines are applicable only to short regions and do not extend over the whole spectrum

  19. Tritium production in a sphere of 6LiD irradiated by 14-MeV neutrons

    International Nuclear Information System (INIS)

    The specific production of tritium in samples of 6LiH and 7LiH embedded in a 600-mm-diam sphere of 6LiD 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 6LiD 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 6Li(n,α) cross section is well known. The specific production of tritium in 6LiH and 7LiH (embedded samples) and the activation of radiochemical detector foils of 45Sc, 89Y, 90Zr, 169Tm, 191Ir 373, 193Ir 627, 197Au, 235U, and 238U placed at various positions in the 6LiD 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

  20. /sup 7/Li production in Nova explosions

    Energy Technology Data Exchange (ETDEWEB)

    Starrfield, S.; Truran, J.W.; Sparks, W.M.; Arnould, M.

    1978-06-01

    Calculations of /sup 7/Li production occurring as a concomitant of thermonuclear runaways in hydrogen envelopes of white dwarfs are reported. It is found that sufficient /sup 7/Li can be produced in models displaying fast--nova-like features to suggest that the corresponding objects represent significant contributors to the /sup 7/Li enrichment of galactic matter. The sensitivities of these results to various assumptions and uncertainties are discussed.

  1. Exploring contributions from incomplete fusion in $^{6,7}$Li+$^{209}$Bi and $^{6,7}$Li+$^{198}$Pt reactions

    CERN Document Server

    Parkar, V V; Kailas, S

    2016-01-01

    We use the breakup absorption model to simultaneously describe the measured cross-sections of the Complete fusion (CF), Incomplete fusion (ICF), and Total fusion (TF) in nuclear reactions induced by weakly bound nuclei $^{6,7}$Li on $^{209}$Bi and $^{198}$Pt targets. The absorption cross-sections are calculated using the Continuum Discretized Coupled Channels (CDCC) method with different choices of short range imaginary potentials to get the ICF, CF and TF cross-sections. It is observed that the cross-sections for deuteron-ICF/deuteron-capture are of similar magnitude as the $\\alpha$-ICF/$\\alpha$-capture, in case of $^{6}$Li projectile, while the cross-sections for triton-ICF/triton-capture is more dominant than $\\alpha$-ICF/$\\alpha$-capture in case of $^{7}$Li projectile. Both these observations are also corroborated by the experimental data. The ratio of ICF to TF cross-sections, which defines the value of fusion suppression factor is found to be in agreement with the data available from the literature. The...

  2. 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. PMID:25105610

  3. 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.

  4. Mechanisms of emission of particles charged in 6Li + 6Li and 6Li + 10B reactions at low energies

    International Nuclear Information System (INIS)

    The lithium 6 nucleus is a projectile of interest to study nuclear reactions at low energy due to the possibility to obtain high heats of reaction, and to its structure which can play an important role in the projectile-target interaction. This research thesis focused on the study of two low-energy reactions provoked by lithium projectiles. These reactions are studied within the framework of the theoretical model of aggregates. The first part presents the experimental conditions of both reactions, reports the development and analysis of nuclear plates, and the transformation of a given type of particle histogram into a spectrum in the mass centre system. The next parts report the study of the 6Li + 6Li reaction (previous results, kinematic analysis, spectrum of secondary particles, theoretical analysis of results) and of the 6Li + 10B reaction (previous results, experimental results, study of the continuous spectrum of alpha particle, reaction mechanisms)

  5. 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.

  6. Primordial α +d →6Li+γ reaction and second lithium puzzle

    Science.gov (United States)

    Mukhamedzhanov, A. M.; Shubhchintak, Bertulani, C. A.

    2016-04-01

    During the Big Bang, 6Li was synthesized via the 2H(α ,γ ) 6Li reaction. After almost 25 years of the failed attempts to measure the 2H(α ,γ ) 6Li reaction in the laboratory at Big Bang energies, just recently the LUNA Collaboration presented the first successful measurements at two different Big Bang energies [Anders et al., Phys. Rev. Lett. 113, 042501 (2014), 10.1103/PhysRevLett.113.042501]. In this paper we will discuss how to improve the accuracy of the direct experiment. To this end the photon's angular distribution is calculated in the potential model. It contains contributions from electric dipole and quadrupole transitions and their interference, which dramatically changes the photon's angular distribution. The calculated distributions at different Big Bang energies have a single peak at ˜50∘ . These calculations provide the best kinematic conditions to measure the 2H(α ,γ ) 6Li reaction. The expressions for the total cross section and astrophysical factor are also derived by integrating the differential cross section over the photon's solid angle. The LUNA data are in excellent agreement with our calculations using a potential approach combined with a well established asymptotic normalization coefficient for 6Li→α +d . Comparisons of the available experimental data for the S24 astrophysical factor and different calculations are presented. The Big Bang lithium isotopic ratio 6Li/7Li=(1.5 ±0.3 ) ×10-5 following from the LUNA data and the present analysis are discussed in the context of the disagreement between the observational data and the standard Big Bang model, which constitutes the second lithium problem.

  7. Feshbach resonances in fermionic 6Li

    International Nuclear Information System (INIS)

    Feshbach resonances in 6Li were experimentally studied and theoretically analyzed. In addition to two previously known s-wave resonances, three p-wave resonances were found. Four of these resonances are narrow and yield a precise value of the singlet scattering length. The position of the broad s-wave resonance near 83 mT is mostly sensitive to the triplet potential. It was previously determined in a molecule-dissociation experiment for which we, here, discuss systematic shifts

  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. Lattice dynamics in Bosonic 7 Li

    Science.gov (United States)

    Chen, Huiyao Y.; Jung, Minwoo; Rabinowitz, Jacob; Madjarov, Ivaylo S.; Cheung, Hil F. H.; Patil, Yogesh Sharad; Vengalattore, Mukund

    2016-05-01

    The light mass and strong spin-dependent interactions in 7 Li make it an attractive candidate to study Bosonic quantum magnetism and lattice dynamics in regimes where rapid dynamics is favored, e.g. percolative transport and entropy segregation. Such studies require large ensembles of quantum degenerate 7 Li atoms which has proved to be a technical challenge. We describe our ongoing efforts to overcome this challenge using Raman sideband cooling (RSC). In addition to enabling the rapid production of large degenerate gases, RSC is also a very powerful means of local control of lattice gas dynamics. Extending this to a spinful 7 Li Bose gas will also enable studies of transport and defect dynamics in F=1 lattice gases. This work is supported by the ARO MURI on non-equilibrium dynamics.

  10. Single-Proton Pickup Reaction of the Halo Nucleus 6He on a 9Be Target at 25 MeV/nucleon

    Institute of Scientific and Technical Information of China (English)

    PANG Dan-Yang; LOU Jian-Ling; LU Fei; FAN Feng-Ying; A. Ozawa; Y. Yamaguchi; R. Kanungo; D. Fang; I. Tanihata; YE Yan-Lin; JIANG Dong-Xing; ZHENG Tao; LI Zhi-Huan; LI Xiang-Qing; GE Yu-Cheng; HUA Hui; WU Cui-E

    2007-01-01

    The inclusive differential cross sections of the 7 Li nucleus in a reaction induced by 6He on a 9Be target are measured at an incident energy of 25 MeV/nucleon. Finite-range distorted-wave Born approximation calculations suggest that these 7 Li particles are formed in a direct single-proton pickup reaction 9 Be(6 He, 7 Li)8 Li. The experimental data can be well reproduced by taking into account of the contributions of both the ground states and the first excited states of 7 Li and 8 Li.

  11. Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions

    International Nuclear Information System (INIS)

    The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented

  12. Reaction mechanism study of 7Li(7Li, 6He) reaction at above Coulomb barrier energies

    Indian Academy of Sciences (India)

    V V Parkar; V Jha; S Santra; B J Roy; K Ramachandran; A Shrivastava; K Mahata; A Chatterjee; S Kailas

    2009-02-01

    The elastic scattering and the 6He angular distributions were measured in 7Li + 7Li reaction at two energies, lab = 20 and 25 MeV. FRDWBA calculations have been performed to explain the measured 6He data. The calculations were very sensitive to the choice of the optical model potentials in entrance and exit channels. The one-step proton transfer was found to be the dominant reaction mechanism in 6He production.

  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. 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.

  15. 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.

  16. Influence of projectile breakup in the elastic scattering of the systems 6,7Li+80Se

    Directory of Open Access Journals (Sweden)

    Cardona M.A.

    2011-10-01

    Full Text Available In order to study the influence of the breakup channel in the elastic scattering of the 6,7Li+80Se systems, we have measured angular distributions at center- of-mass energies from 13 ≤ Ec.m. ≤ 24 MeV (0.8VCB up to 1.6VCB . They were analyzed within the framework of the optical model to study the energy dependence of the real and imaginary parts of the nuclear potential. The focus was to investigate the threshold anomaly in those weakly bound systems. The behavior of the calculated potentials as a function of energy indicates that our results are consistent with the dispersion relation. The threshold anomaly was observed in the 7Li+80Se system and the breakup threshold anomaly was confirmed for the 6Li+80Se system.

  17. 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.

  18. Studies of the D state of 6Li using the FSU polarized 6Li Beam

    International Nuclear Information System (INIS)

    One way to quantify the D-state component of the wave function of a nucleus is by the quantity η, the ratio of the D- and S-state asymptotic normalization constants. Analyses of the analyzing powers from transfer reactions induced by polarized ions have been useful for the determination of η in the A=2-4 systems. In an effort to determine η for the d+α relative motion in 6Li we have measured analyzing powers for (6L rvec i,d) reactions on 58Ni and 40Ca at E(6Li)=34 and h;MeV. The experiments were performed at Florida State University using the Optically Pumped Polarized Lithium Ion Source. We compared the data with the results of well-constrained DWBA calculations assuming a direct α-particle transfer mechanism. With η the only free parameter in the calculations, a best fit to the tensor analyzing power data results in an average value of η=+0.0003±0.0009, much smaller than previous determinations. copyright 1999 American Institute of Physics

  19. Enhancement of the CP-odd effect in the nuclear electric dipole moment of $^6$Li

    CERN Document Server

    Yamanaka, Nodoka

    2015-01-01

    We calculate for the first time the electric dipole moment (EDM) of the $^6$Li nucleus within the alpha + p + n three-body cluster model using the Gaussian expansion method, assuming the one meson exchange P, CP-odd nuclear forces. It is found that the EDM of the $^6$Li is 2 times more sensitive on the isovector pion exchange P, CP-odd nuclear force than the deuteron EDM, due to the CP-odd interaction between the nucleons and the alpha cluster. The $^9$Be EDM is also calculated in the same framework as an alpha + alpha + n three-body system. We also test the ab initio calculation of the EDM of the deuteron, $^3$H and $^3$He nuclei using the realistic Argonne $v18$ nuclear force. In the ab initio calculations, good agreements with previous studies are obtained. We finally discuss the prospects for the new physics beyond the standard model.

  20. 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.

  1. Fusion around the barrier for 7Li + 12C

    Indian Academy of Sciences (India)

    A Mukherjee; M Dasgupta; D J Hinde; C R Morton; A C Berriman; R D Butt; J O Newton; H Timmers

    2001-07-01

    Fusion cross-sections for the 7Li + 12C reaction have been measured at energies above the Coulomb barrier by the direct detection of evaporation residues. The heavy evaporation residues with energies below 3 MeV could not be separated out from the -particles in the spectrum and hence their contribution was estimated using statistical model calculations. The present work indicates that suppression of fusion cross-sections due to the breakup of 7Li may not be significant for 7Li + 12C reaction at energies around the barrier.

  2. Relation between (e,e') sum rules in 6,7Li and 4He nuclei.Experiment and cluster model

    CERN Document Server

    Efros, V D; Buki, A Yu

    2016-01-01

    The sums over (e,e') spectra of 6Li and 7Li 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 alpha-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^{-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^{-1} the longitudinal correlation functions of 6Li and 7Li nuclei are found to be close to that of the alpha-particle. The experimental longitudinal sums in the range between 0.450 and 1.625 fm^{-1} are employed to perform comparison with those calculated in the framework of cluster models. Out of the mentioned experimental sums, those in the range between 0.750 and 1.000 fm^{-1} in the 6Li case ...

  3. CDCC calculations of elastic scattering for the systems 6Li+144Sm and 6Li+208Pb. Effect of resonances of 6Li on elastic scattering angular distributions

    International Nuclear Information System (INIS)

    Calculations of elastic scattering angular distributions for reactions of the weakly bound projectile 6Li with targets 144Sm and 208Pb at energies above the barrier, are performed with the Continuum Discretized Coupled-Channel method (CDCC). Ground, resonant and nonresonant continuum states of 6Li are included up to some maximum energy εmax for which convergence is achieved. In the three-body system, global interactions are used for the α-target and d - target sub-systems. The effect of continuum resonant states of 6Li, i.e., l = 2, jπ = 3+, 2+ and 1+ on elastic scattering angular distributions is investigated by extracting these states from the continuum space. It is found that the calculated elastic scattering angular distributions are in good agreement with the measurements for most of the cases studied where consideration of couplings to continuum states is essential. It is also found that the resonance character of the continuum states is in some cases important to obtain agreement with the data

  4. 7Li NMR studies of lithium transport in human erythrocytes

    International Nuclear Information System (INIS)

    Lithium transport in human erythrocytes was investigated by 7Li NMR spectroscopy. The intra- and extracellular pools of Li+ were distinguished by the addition to the red cell suspension of a cell-impermeable shift reagent, dysprosium(III) triphosphate. It was found that, for therapeutic levels of lithium used in the US (where the typical plasma (Li+) concentration range is 0.5-1.2 mM), a shift reagent concentration of 3 mM is sufficient to achieve clear chemical shift separation between the two 7Li+ NMR resonances. Despite competition between Li+ and other mono- and divalent cations for the shift reagent, the intra and extracellular 7Li+ NMR signals are clearly separated (approximately 3 ppM) even in the presence of physiologically relevant concentrations of Na+, K+, Mg2+, and Ca2+. Addition of an ionophore, monesin, to a K+-only RBC (red blood cell) suspension induces passive Li+ transport, which can be monitored by following the relative intensities of the two 7Li+ resonances. It is concluded that the 7Li NMR method is suitable for the noninvasive study of Li+ transport in human erythrocytes and that it shows great promise as a tool for the investigation of the bioinorganic chemistry of lithium. 24 references, 3 figures, 1 table

  5. 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.

  6. Resonant and nonresonant Coulomb break up of 6Li

    International Nuclear Information System (INIS)

    The resonant and nonresonant cross section for break up of 6Li in the Coulomb field of a heavy nucleus is theoretically studied on the basis of a DWBA approach and analysed in view of a possible experimental access to electromagnetic transition matrix elements between the ground state of the projectile and α+d continuum states at small relative energies. The calculation explicitly uses some simplifications appearing in the particular case of quadrupole transitions which dominate the considered case. Various sensitivities of the cross sections are discussed. (orig.)

  7. Study of the {sup 6}He+{sup 9}Be elastic scattering at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Pires, K.C.C.; Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P.N.; Crema, E.; Barioni, A.; Mendes Junior, V.; Morcelle, V.; Morais, M.C.; Pampa Condori, R.; Huiza, J.F.P. [Universidade de Sao Paulo (IF/USP), SP (Brazil). lnst. de Fisica. Dept. de Fisica Nuclear; Moro, A.M.; Rodriguez-Gallardo, M. [University of Seville (Sri Lanka). Dept. of Atomic, Molecular and Nuclear Physics; Assuncao, M. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP) Sao Paulo, SP (Brazil); Mukherjee, S. [University of Baroda, Vadodara (India). Faculty of Science. Dept. of Physics

    2011-07-01

    New data of the {sup 6}He+{sup 9}Be elastic scattering at E{sub lab}=16.2MeV and 21.3MeV have been measured. A very large reaction cross section has been previously observed in the collision of {sup 6}He with medium and heavy mass targets, which has been attributed to high 6He breakup probability in the strong Coulomb + nuclear interaction. More recently the importance of neutron transfer reactions between projectile and target has been pointed out. The main goal of the present experiment is to investigate the halo nature of the {sup 6}He nucleus by its interaction with a light target. The experiment has been performed at the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo, Brazil, using the RIBRAS facility. The RIBRAS system consists of two superconducting solenoids used to focus and select the radioactive secondary beam. The {sup 6}He secondary beam was produced by the {sup 9}Be({sup 7}Li,{sup 6}He) reaction with a {sup 7}Li primary beam of 200nA. The detection system consisted of four {Delta}E-E Silicon telescopes, with 20{mu}m and 1000{mu}m thickness respectively, which allow to separate the {sup 6}He particles from the {sup 7}Li, {sup 4}He, and light particles contaminants. The {sup 6}He+{sup 9}Be angular distributions have been analyzed with optical model, Coupled Channels (CC) and Continuum Discretized Coupled Channels (CDCC) calculations. The comparison between the experimental data and the CDCC calculations allow us to conclude that the breakup of the projectile via the coupling to the {sup 6}He 2{sup +} resonance is very important to reproduce the data. In addition, we studied the effect of excitation of the {sup 9}Be target explicitly by a CC calculation, using a collective model to describe the excitation of the first low lying states of {sup 9}Be. We found that the coupling to these states significantly affects the elastic scattering. From this analysis it was possible to obtain the total reaction cross section which was

  8. Lowest excitation energy of 9Be.

    Science.gov (United States)

    Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik

    2007-07-27

    Variational calculations employing explicitly correlated Gaussian functions and explicitly including the nuclear motion [i.e., without assuming the Born-Oppenheimer (BO) approximation] have been performed to determine the lowest singlet transition energy in the 9Be atom. The non-BO wave functions were used to calculate the alpha2 relativistic corrections (alpha=1/137.035,999,679). With those corrections and with the alpha3 and alpha4 QED corrections determined previously by others, we obtained 54,677.35 cm(-1) for the 3(1)S-->2(1)S transition energy. This result falls within the error bracket for the experimental transition of 54,677.26(10) cm(-1). This is the first time an electronic transition of Be has been calculated from first principles with the experimental accuracy. PMID:17678358

  9. Ab initio no-core solutions for $^6$Li

    CERN Document Server

    Shin, Ik Jae; Maris, Pieter; Vary, James P; Forssén, Christian; Rotureau, Jimmy; Michel, Nicolas

    2016-01-01

    We solve for properties of $^6$Li in the ab initio No-Core Full Configuration approach and we separately solve for its ground state and $J^{\\pi}=2_{2}^{+}$ resonance with the Gamow Shell Model in the Berggren basis. We employ both the JISP16 and chiral NNLO$_{opt}$ realistic nucleon-nucleon interactions and investigate the ground state energy, excitation energies, point proton root-mean-square radius and a suite of electroweak observables. We also extend and test methods to extrapolate the ground state energy, point proton root-mean-square radius, and electric quadrupole moment. We attain improved estimates of these observables in the No-Core Full Configuration approach by using basis spaces up through N$_{max}$=18 that enable more definitive comparisons with experiment. Using the Density Matrix Renormalization Group approach with the JISP16 interaction, we find that we can significantly improve the convergence of the Gamow Shell Model treatment of the $^6$Li ground state and $J^{\\pi}=2_{2}^{+}$ resonance by ...

  10. 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.

  11. Spontaneous Lithium Transportation via LiMn2O4/Electrolyte Interface Studied by 6/7Li Solid-State Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    Highlights: • Spontaneous Li+ exchange between LiMn2O4 and LiPF6-based electrolyte was studied. • 6/7Li solid-state NMR techniques were developed to examine the exchange. • The exchange occurs for stoichiometric LiMn2O4 but not in Li-excess LiMn2O4. • The exchange was approximated by the 1st-order reaction with the rate of 0.024 min-1. • The suppression in Li-excess LiMn2O4 was ascribed to excess amount of Mn4+. - Abstract: Lithium transportation across the interface of LiMn2O4/LiPF6-based electrolyte was studied by 6/7Li solid-state NMR with 6Li-enriched LiPF6. For almost stoichiometric LiMn2O4, we show that exchange of lithium ions occurs across an electrolyte/electrode interface just by immersing LiMn2O4 powder into LiPF6-based electrolyte, while such transportation is suppressed in Li-excess LiMn2O4. The exchange was approximated by the 1st-order reaction, and the rate was estimated from the 6Li/7Li intensities to be 0.024 min−1 at room temperature. The lithium ions penetrated into the surface of a LiMn2O4 particle reach to the core with a time scale of a few hours at room temperature. The suppression of the exchange in Li-excess LiMn2O4 was ascribed to the presence of excess amount of Mn4+

  12. 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.

  13. Neutron spectrum measurements in CFRMF by 6Li spectrometry

    International Nuclear Information System (INIS)

    The neutron energy spectrum of the Couples Fast Reactivity Measurements Facility (CFRMF) has been measured by the 6Li(n,α)t spectrometry technique between the energies of 10 keV and 8 MeV. These measurements were made in order to improve the knowledge of this benchmark neutron field as related to dosimetry and other integral cross sections. Energy spectra of both the α + t and t responses were obtained simultaneously using two-parameter multichannel pulse height analysis. Spectrometers of different design and resolution characteristics were applied. The data were reduced using recently evaluated cross section information. The results are compared with the neutron spectrum calculated using recently evaluated cross section information. (author)

  14. Neutron-induced background by an {alpha}-beam incident on a deuterium gas target and its implications for the study of the {sup 2}H({alpha},{gamma}){sup 6}Li reaction at LUNA

    Energy Technology Data Exchange (ETDEWEB)

    Anders, M.; Bemmerer, D.; Elekes, Z.; Marta, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Trezzi, D.; Mazzocchi, C. [INFN, Sezione di Milano, Milano (Italy); Bellini, A.; Costantini, H.; Corvisiero, P.; Lemut, A.; Prati, P. [Universita di Genova (Italy); INFN, Sezione di Genova, Dipartimento di Fisica, Genova (Italy); Aliotta, M.; Davinson, T.; Scott, D. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Broggini, C.; Caciolli, A.; Erhard, M.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Formicola, A.; Junker, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Fueloep, Zs.; Gyuerky, G.; Somorjai, E.; Szuecs, T. [Institute of Nuclear Research (ATOMKI), Debrecen (Hungary); Gervino, G. [Universita di Torino (Italy); INFN, Dipartimento di Fisica Sperimentale, Torino (Italy); Guglielmetti, A. [INFN, Sezione di Milano, Milano (Italy); Universita degli Studi di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [INFN, Sezione di Napoli, Napoli (Italy); Osservatorio Astronomico di Collurania, Teramo (Italy); Collaboration: LUNA Collaboration

    2013-02-15

    The production of the stable isotope {sup 6}Li in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological {sup 6}Li plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of {sup 7}Li abundances and would point to a predominantly primordial origin of {sup 6}Li, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang {sup 6}Li production must be revisited. The main production channel for {sup 6}Li in the Big Bang is the {sup 2}H({alpha},{gamma}){sup 6}Li 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 {sup 2}H(d,n){sup 3}He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400keV {alpha}-beam energy and for comparison also using an americium-beryllium neutron source. (orig.)

  15. Fast Neutron Detection with 6Li-loaded Liquid Scintillator

    CERN Document Server

    Fisher, B M; Coakley, K J; Gavrin, V N; Gilliam, D M; Nico, J S; Shikhin, A A; Thompson, A K; Vecchia, D F; Yants, V E

    2011-01-01

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

  16. Towards 6Li-40K ground state molecules

    International Nuclear Information System (INIS)

    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 6Li-40K 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 6Li-40K 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 of the resonance

  17. Spectator invariance test in the study of the Trojan Horse Method 6,7Li fusion reactions via the Trojan Horse Method

    Directory of Open Access Journals (Sweden)

    Li C.

    2011-10-01

    Full Text Available Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even sometimes impossible. In such cases the use of indirect methods can give a substantial help. The Trojan Horse Method (THM is based on the quasi-free break-up of a nucleus, which can be described in terms of a cluster structure. In such applications the independence of THM results with different break-up schemes, was tested using the quasi free3 He(6Li,ααH and 3He(7Li,αα2H reactions. Results were then compared with the direct behaviours obtained from available data as well as with the cross sections extracted from previous indirect investigations of the same binary reactions using a different nuclide as a Trojan Horse nucleus.

  18. Detection of the inverse pion electroproduction on 7Li nuclei

    International Nuclear Information System (INIS)

    The inverse pion electroproduction process on 7Li nucleus, π++7Li→e++e-+X, at the pion kinetic energy of 380 MeV has been detected. The missing mass distribution of the process events is described well assuming that approximately one half of the detected events belongs to the reaction channel producing 7Be nucleus either in the ground state (7Be) or in the excited state (7Be*): π++7Li→e++e-+7Be(7Be*). For this reaction the differential cross section for the electron and positron energies above 70 MeV, for the particles emitted under an angle of about 65 deg in l. s., is d2σ/dΩ2=(1.3+-0.3)x10-32 cm2/sr2

  19. Development of {sup 6}LiF thermal neutron shield for PGNAA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. S.; Park, J. H.; Hong, K. W.; Jun, B. J. [KAERI, Taejon (Korea, Republic of); Bun, S. H.; Choi, H. D. [Seoul National Univ., Seoul (Korea, Republic of)

    2001-05-01

    The {sup 6}LiF tile which will be utilized as the neutron shield of the gamma ray detector at the prompt gamma neutron activation analysis facility of KAERI-HANARO is developed. The {sup 6}LiF powder is obtained by the reaction of hydrofluoric acid with the {sup 6}Li{sub 2}CO{sub 3} powder, and the yield of the {sup 6}LiF is 86% of the theoretical value. In order to fabricate the stable tile from toxic and irritant LiF powder, the optimum sintering procedure is developed using the LiF powder with naturally abundant {sup 6}Li. The sintering temperature is 720 .deg. C, and the heating rate is 120 .deg. C/h. The preliminary heating process at 500 .deg. C is added in fabricating the {sup 6}LiF tile. The density of fabricated LiF tile is 2.4{approx}2.5 g/cm{sup 3}, and it is above 90% of theoretical density. The density of fabricated {sup 6}LiF tile is 2.25 g/cm{sup 3}, and the neutron transmission rate is below 10{sup -8}, so the thermal neutron transmission is negligible. Therefore, the tile is confirmed to be useful for PGNAA facility.

  20. 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...

  1. Direct measurement of the spin-dependent capture and scattering of slow neutrons by 6Li

    International Nuclear Information System (INIS)

    The spin-dependent capture cross section sigma/sup c//sub +/-sigma/sup c//sub -/ of slow neutrons (lambda = 1.074 A) by 6Li has been determined from the flipping ratio of a transmitted polarized neutron beam as a function of 6Li polarization. We used two methods, one of which also enabled us to measure the spin-dependent scattering length b/sub +/-b/sub -/ of 6Li. We find sigma/sub +//sup c/-sigma/sub -//sup c/ = -1170 +- 50 b and b/sub +/-b/sub -/ = (-0.38 +- 0.05) x 10-12 cm

  2. Spin-dipole excitations of 6Li in charged pion photoproduction

    International Nuclear Information System (INIS)

    In the framework of bound shell model the photoproduction cross sections of charged pions on 6Li are calculated when spin-isospin dipole resonance is excited. It is shown that the transition strenqth concentrates in several energy regions. Such a gross-structure of the excitation spectrum is gaverned by the confiqurational splittinq of the resonance. The excitation spectrum in 6Li(γ, π)-reaction is compared with the 6Li(π, γ), (e, e') and (n, p) reaction spe;tra where spin-isospin transitions are dominating too

  3. 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)

  4. Prospects of lithium enrichment on 7Li isotope by method of controlled ions electro-migration

    Science.gov (United States)

    Martoyan, G. A.; Kalugin, M. M.; Gabrielyan, A. V.; Martoyan, A. G.

    2016-01-01

    This paper deals with a new electro-membrane method of enrichment of 7Li isotope. The data are presented on the importance and application fields regarding the use of 7Li isotopes. Existing methods and criteria of separation of lithium isotopes are discussed. The principle of new technology, regimes of enrichment experiments, and analysis details of obtained products are briefly described.

  5. Use of 7Li(p,n) reaction as a neutron source in a PGNAA setup.

    Science.gov (United States)

    Naqvi, A A; Nagadi, M M

    2005-03-01

    The performance of a 7Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a 7Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the 7Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the 7Li(p,n) reaction-based setup. The prompt gamma-ray yield from the 7Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the 7Li(p,n) reaction-based setup is comparable with that of a previously studied 3H(p,n) reaction-based setup, yet performance of the 7Li(p,n) reaction-based setup is superior to that of the 3H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a 7Li(p,n) reaction-based PGNAA setup. PMID:15607917

  6. Use of 7Li(p,n) reaction as a neutron source in a PGNAA setup

    International Nuclear Information System (INIS)

    The performance of a 7Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a 7Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the 7Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the 7Li(p,n) reaction-based setup. The prompt γ-ray yield from the 7Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the 7Li(p,n) reaction-based setup is comparable with that of a previously studied 3H(p,n) reaction-based setup, yet performance of the 7Li(p,n) reaction-based setup is superior to that of the 3H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a 7Li(p,n) reaction-based PGNAA setup

  7. Determination of nuclear reduced transition probabilities by 7Li ion induced Coulomb excitation

    International Nuclear Information System (INIS)

    Recently the authors observed that the first excited state of 7Li nucleus was excited in 7Li ion-Cu collision in the energy range 4.9 to 11.9 MeV, and the excitation process was via Coulomb excitation. By using the well known B (E2; g.s. 3-/2 - 478 keV, 1-/2) value of 7Li nucleus and the 7Li induced Coulomb excitation yields of both 7Li projectile and targets, the authors determined the reduced transition probabilities for low-lying states of some medium weight nuclei. The reduced transition probabilities determined this way are free from uncertainties due to target thickness and incident particle collection

  8. Effects of nuclear breakup channel on fusion of 6Li+64Zn system around barrier energies

    International Nuclear Information System (INIS)

    We have studied the effects of breakup, occurring due to the nuclear interaction between weakly bound 6Li and tightly bound 64Zn isotopes, on the fusion reaction at near barrier energies within the framework of dynamic polarization potential (DPP) approach. When the nuclear induced dynamic polarization potential is taken into account sub barrier enhancement and above barrier suppression have been found which improves the matching between the fusion excitation function data and predictions for 6Li+64Zn system significantly. (author)

  9. Importance of the tensor interaction in the (/sup 7/Li, /sup 7/Be) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Dodd, A.C.; Clarke, N.M.; Coopersmith, J.; Griffiths, R.J.; Pearce, K.I.; Stanley, B.; Cook, J.

    1985-09-01

    Data for the /sup 28/Si(/sup 7/Li, /sup 7/Be)/sup 28/Al reaction at 72 MeV and for the /sup 26/Mg(/sup 7/Li, /sup 7/Be)/sup 26/Na reaction at 88 MeV are presented together with one-step DWBA calculations using microscopic form factors. The tensor interaction is shown to be important to explain the structureless nature of the angular distributions.

  10. The importance of the tensor interaction in the (7Li, 7Be) reaction

    International Nuclear Information System (INIS)

    Data for the 28Si(7Li, 7Be)28Al reaction at 72 MeV and for the 26Mg(7Li, 7Be)26Na reaction at 88 MeV are presented together with one-step DWBA calculations using microscopic form factors. The tensor interaction is shown to be important to explain the structureless nature of the angular distributions. (author)

  11. Thermal neutron calibration of a tritium extraction facility using the 6Li(n,t)4He/197Au(n,γ)198Au cross section ratio for standardization

    International Nuclear Information System (INIS)

    Absolute tritium activities in a neutron-activated metallic lithium samples have been measured by liquid scintillation methods to provide data needed for the determination of capture-to-fission ratios in fast breeder reactor spectra and for recent measurements of the 7Li(n,n't)4He cross section. The tritium extraction facility used for all these experiments has now been calibrated by measuring the 6Li(n,t)4He/197Au/n,γ)198Au activity ratio for thermal neutrons and comparing the result with the well-known cross sections. The calculated-to-measured activity ratio was found to be 1.033 +- 0.018. 2 figures, 20 tables

  12. Study of direct and sequential break-up reactions in 6Li+ 112Sn system

    International Nuclear Information System (INIS)

    The 6Li projectile while moving in the field of a target nucleus can not only dissociate into α+d but it can also first exchange a few nucleon with the target and then break up into two fragments. Identification of all these processes is important to understand the break-up mechanism of 6Li projectile and also to find the origin of the high yield of alpha particle production in such a reaction. In this paper, we present the exclusive measurement of breakup cross sections in 6Li+112Sn reaction exploring the above possibilities. Cross sections for both sequential as well as direct breakup are measured and compared with the theoretical calculations. The measured elastic scattering angular distributions were used as a constraint to the potential parameters that were used in the calculations to explain both elastic scattering and the breakup processes simultaneously

  13. 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.

  14. 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.

  15. The In Situ Polymerization and Characterization of PA6/LiCl Composites

    Directory of Open Access Journals (Sweden)

    Dandan Sun

    2013-01-01

    Full Text Available PA6/LiCl composites were synthesized by in situ anionic polymerization based on the interaction between the inorganic salts and PA6. Sodium hydroxide as initiator and N-acetylcaprolactam as activator were used in the preparation of PA6/LiCl composites with variety of LiCl content. X-ray diffraction (XRD and differential scanning calorimeter (DSC testing results showed that both of degree of crystallinity and melting temperature of the composites were decreased under the influence of LiCl. And the γ crystal phase proportion increased with increasing the LiCl content to appropriate amount.

  16. 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.

  17. Study of reactions induced by 6He on 9Be

    Directory of Open Access Journals (Sweden)

    Pires K.C.C.

    2014-03-01

    Full Text Available We present the results of experiments using a 6He beam on a 9Be target at energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic scattering (target breakup and the a-particle production in the 6He+9Be collision have been analysed. Total reaction cross sections were obtained from the elastic scatteringanalyses and a considerable enhancement has been observed by comparing to stable systems.

  18. Role of projectile breakup in {sup 6}He and {sup 6}Li induced fusion reactions around barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anju; Kharab, Rajesh, E-mail: kharabrajesh@rediffmail.com

    2015-09-15

    The influence of projectile breakup on fusion cross section for {sup 6}He + {sup 209}Bi, {sup 6}He + {sup 64}Zn, {sup 6}Li + {sup 209}Bi and {sup 6}Li + {sup 64}Zn reactions at near barrier energies is studied within the framework of quantum diffusion approach. The breakup does not affect the fusion induced by {sup 6}He, whereas a significant suppression for {sup 6}Li induced reaction is observed in below barrier energy region.

  19. 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).

  20. Optical model studies of 6Li elastic scattering at 156 MeV

    International Nuclear Information System (INIS)

    Differential cross sections for 6Li elastic scattering at 156 MeV from 12C, 40Ca 90Zr and 208Pb are presented. The sensitivity to various potential forms is established by using Saxon Woods, Saxon-Woods-squred, density independent and density dependent folded potentials. The extent to which the experimental data determine the potentials and related quantities is discussed. (orig.)

  1. Reactions (d,7Li) and (d,7Be) in 19F nuclei

    International Nuclear Information System (INIS)

    Differential cross sections have been measured for the reactions 19F(d,7Li)14N, 19F(d,7Li(/sub 0.478/)14N, 19F(d,7Be)14C, and 19F(d,7Be(/sub 0.429/)14C in a cyclotron beam of deuterons with energy 13.6 MeV. The experimental data were analyzed by the distorted-wave method with inclusion of the finite interaction range and recoil. It is shown that the reactiuns 19F(d,7Li)14N and 19F(d,7Li(/sub 0.478/)14N occur mainly by direct transfer of a 5He cluster from the 4P/sub 1/2/ state of the 19F nucleus to the 1D/sub 3/2/ state of the 7Li nucleus. The differential cross sections for the reactions 19F(d,7Be)14C and 19F(d,7Be(/sub 0.429/)14C could not be explained in terms of the theory of direct transfer of a 5Li cluster

  2. Tagging fast neutrons from an (241)Am/(9)Be source.

    Science.gov (United States)

    Scherzinger, J; Annand, J R M; Davatz, G; Fissum, K G; Gendotti, U; Hall-Wilton, R; Håkansson, E; Jebali, R; Kanaki, K; Lundin, M; Nilsson, B; Rosborge, A; Svensson, H

    2015-04-01

    Shielding, coincidence, and time-of-flight measurement techniques are employed to tag fast neutrons emitted from an (241)Am/(9)Be source resulting in a continuous polychromatic energy-tagged beam of neutrons with energies up to 7MeV. The measured energy structure of the beam agrees qualitatively with both previous measurements and theoretical calculations. PMID:25644080

  3. Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies

    Directory of Open Access Journals (Sweden)

    Luong D.H.

    2013-12-01

    Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.

  4. Faddeev calculations for the Λ9Be spectrum

    Directory of Open Access Journals (Sweden)

    Vlahovic B.

    2010-04-01

    Full Text Available An α-cluster model is applied to study low-lying spectrum of the Λ9Be hypernicleus. The ααΛ three-body problem is numerically solved by the Faddeev equations in configuration space using phenomenological pair potentials. Found is a set of the potentials that reproduces experimental data for the ground state (1+/2 binding energy and excitation energy of the 5+/2 and 3+/2 states, simultaneously. This set includes the Ali-Bodmer potential of version “e” for αα and modified Tang-Herndon potential for αΛ interactions. The spin-orbit αΛ interaction is given by modified Scheerbaum potential. Low-lying energy levels are evaluated applying a variant of the analytical continuation method in coupling constant, and the experimental data for excitation energies are well reproduced by our calculations. This result improves previous α-cluster calculations. It is shown that the spectral properties of Λ9Be can be classified as an analog of 9Be spectrum with the exception of several “genuine hypernuclear states”, which agrees qualitatively with previous studies. The energy splitting of spin-flip doublet (9+/2 , 7+/2 is predicted.

  5. Extremely slow cation exchange processes in Li4SiO4 probed directly by two-time 7Li stimulated-echo nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Lithium self-diffusion in the low-temperature modification of polycrystalline lithium ortho-silicate Li4SiO4 is investigated by 7Li two-time stimulated echo NMR spectroscopy. Extremely slow Li exchange processes were directly monitored between 300 and 433 K by recording spin-alignment echoes as a function of mixing time varying over six decades from 10-5 to 10 s. In the investigated temperature range the hopping correlation functions show biexponential behaviour. Whereas the first decay step reflects directly Li jumps between electrically different sites, the second one is simply induced by the decay of alignment order due to quadrupolar relaxation. The echo decay rates τ-1 (101 s-1≤τ-1≤104 s-1), which can be identified with Li jump rates, show Arrhenius behaviour with an activation energy of 0.53(1) eV. The directly measured jump rates are in good agreement with those obtained recently by one- and two-dimensional 6Li exchange MAS NMR reported in the literature

  6. Radioactive contamination of {sup 7}LiI(Eu) crystal scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Belli, P. [INFN sezione Roma “Tor Vergata”, I-00133 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, I-00133 Rome (Italy); Bernabei, R., E-mail: rita.bernabei@roma2.infn.it [INFN sezione Roma “Tor Vergata”, I-00133 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, I-00133 Rome (Italy); Budakovsky, S.V. [Institute for Scintillation Materials, 61001 Kharkiv (Ukraine); Cappella, F. [INFN sezione Roma “La Sapienza”, I-00185 Rome (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, I-00185 Rome (Italy); Cerulli, R. [INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi (AQ) (Italy); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); D' Angelo, S. [INFN sezione Roma “Tor Vergata”, I-00133 Rome (Italy); Dipartimento di Fisica, Università di Roma “Tor Vergata”, I-00133 Rome (Italy); Incicchitti, A. [INFN sezione Roma “La Sapienza”, I-00185 Rome (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, I-00185 Rome (Italy); Laubenstein, M. [INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi (AQ) (Italy); Poda, D.V. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine); and others

    2013-03-11

    The radioactive contamination of two 26 g samples of low background lithium iodide crystal scintillators doped by europium and enriched in {sup 7}Li to 99.9% ({sup 7}LiI(Eu)) has been investigated by scintillation method at the sea level, and by ultra-low background HPGe γ spectrometry deep underground. No radioactive contamination was detected. In particular, the contamination of the crystal scintillators by {sup 226}Ra and {sup 228}Th does not exceed 1 mBq/kg, and the activity of {sup 40}K is less than 0.5 Bq/kg.

  7. Search for a resonant enhancement of the 7Be + d reaction and primordial 7Li abundances

    International Nuclear Information System (INIS)

    Big Bang nucleosynthesis calculations, constrained by the Wilkinson Microwave Anisotropy Probe results, produce 7Li abundances almost a factor of four larger than those extrapolated from observations. Since primordial 7Li is believed to be mostly produced by the beta decay of 7Be, one proposed solution to this discrepancy is a resonant enhancement of the 7Be(d,p)2α reaction rate through the 5/2+ 16.7-MeV state in 9B. The 2H(7Be,d)7Be reaction was used to search for such a resonance; none was observed. An upper limit on the width of the proposed resonance was deduced.

  8. Report for in-situ 7Li NMR experiment in PNNL Phase -1

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi [Pacific Northwest National Laboratory

    2014-08-19

    To understand the detailed local structural evolution, an in-situ 7Li NMR study was performed. An operando identification of the lithium germanide phases under various cycling regimens permitted understanding of the kinetics of phase transition between different structural phases, including the amorphous phases, and how these correlated with capacity retention. Combining data from TEM and in-situ 7Li NMR, we discovered that the phase inter-conversion during cycling was mediated by co-existing amorphous and crystalline phases, and that the high capacity observed was correlated with an over-lithiated lithium germanide phase.

  9. Search for higher excited states of $^{8}$Be* to study the cosmological $^{7}$Li problem

    CERN Multimedia

    We would like to study the unresolved $^{7}$Li abundance anomaly by carrying out experiments that destroy the rare isotope $^{7}$Be, the main source of $^{7}$Li. Utilizing a 35 MeV $^{7}$Be beam from HIE-ISOLDE, we would like to measure the (d,p) and (d,d) reactions with T-REX. The higher beam energy, for the first time, would allow us to measure higher excitation energies in $^{8}$Be up to about 20 MeV. With a wider angular coverage, we can make improved average cross-section measurement without assuming isotropy done in earlier works.

  10. Determination of degradation constants of energetic 7*Li ion in liquid media using a thin boron film on silicon wafer

    International Nuclear Information System (INIS)

    A novel method to determine degradation constants has been developed for energetic 7*Li ions produced from the 10B (n, α) 7*Li reaction, moving in liquid media. The energetic 7*Li generated in a thin boron film on silicon wafer plunged into a liquid sample in which the wafer was immersed. The degradation constants were determined by analyzing the Doppler-broadened lineshapes of prompt γ-ray at 478 keV emitted from 7*Li. For comparison, degradation constants were also measured for solutions of boron compounds. Values obtained by the two methods gave fair agreement. (author)

  11. 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.

  12. Neutron assay in mixed radiation fields with a 6Li-loaded plastic scintillator

    International Nuclear Information System (INIS)

    A novel technique for assay of thermal and fast neutrons in a 6Li-loaded plastic scintillator is presented. Existing capture-gated thermal neutron detection techniques were evaluated with the 6Li-loaded plastic scintillator studied in this work. Using simulations and experimental work, shortcomings in its performance were highlighted. As a result, it was proposed that by separating the combined fast and thermal neutron events from gamma events, using established pulse shape discrimination techniques, the thermal neutron events could then be assayed. Experiments were conducted at the National Physical Laboratory, Teddington, performing neutron assays with seven different neutron fields using the proposed technique. For each field, thermal and fast neutron content was estimated and were shown to corroborate with the seven synthesised fields

  13. Measurement of the 1H(6He,6Li)n reaction in inverse kinematics

    International Nuclear Information System (INIS)

    The 1H(6He,6Li)n reaction was studied at 0 degree with the NSCL A1200 fragment separator in the energy loss mode. A 6He secondary beam at E/A=93 MeV was used to measure the Gamow-Teller and Fermi strengths between the ground state of 6He and the ground and excited states of 6Li, in inverse kinematics. At 0 degree the ground-state cross section is measured to be dσGS/(dΩ)=43±16 mb/sr, which is dominated by systematic error in the secondary beam flux. The ratio of Gamow-Teller to Fermi strength is not sensitive to this error and is found to be (87±6)% of that expected from (p,n) systematics and β decay. Angular distributions have been measured between 0 degree and 10 degree in the center of mass. copyright 1996 The American Physical Society

  14. 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.

  15. Investigation of the selection of the selectively heated ions of 6Li isotope from lithium plasma

    International Nuclear Information System (INIS)

    Results of experiments on preparation of enriched lithium by means of plasma isotope separation method using ion cyclotron resonance (ICR) are presented. Two types of collectors were compared: cylindrical and plane ones. Both collectors were placed just as in homogeneous magnetic field immediately after the zone of selective ICR heating, so in diverging weakened one, closer to solenoid end. In cylindrical collector higher lithium enrichment by 6Li (up to 83 %) is observed. That corresponds to distribution coefficient ≅60

  16. BEC of 41 K in a Fermi sea of 6 Li

    Science.gov (United States)

    Lous, Rianne S.; Fritsche, Isabella; Huang, Bo; Jag, Michael; Cetina, Marko; Walraven, Jook T. M.; Grimm, Rudolf

    2016-05-01

    We report on the production of a 41 K Bose-Einstein condensate (BEC) immersed in a degenerate two-component 6 Li Fermi sea. After evaporation in an optical dipole trap, we obtain 1 . 2 ×104 41 K atoms with a 55% BEC fraction and a Fermi sea with T /TF work is supported by the Austrian Science Fund FWF within the collaborative research grant FoQuS.

  17. Development of a mini high efficiency neutron detector based on 6LiI (Eu) scintillator

    International Nuclear Information System (INIS)

    A mini neutron detector with the dimension of φ25 mm ×20 mm is developed based on a 6LiI( Eu) scintillator with a Hamamatsu S3590-08 photodiode. The detector was used to detect thermal neutrons from a paraffin shielded 252Cf neutron source and the detect efficiency to thermal neutron was calculated to be 95% with a resolution of thermal neutron peak about 16%. (authors)

  18. 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.

  19. Measurement of interaction energy near a Feshbach resonance in a 6Li Fermi gas

    OpenAIRE

    Bourdel, T; Cubizolles, J.; Khaykovich, L.; Magalhaes, K. M. F.; Kokkelmans, S. J. J. M. F.; G. V. Shlyapnikov; Salomon, C

    2003-01-01

    We investigate the strongly interacting regime in an optically trapped $^6$Li Fermi mixture near a Feshbach resonance. The resonance is found at $800(40) $G in good agreement with theory. Anisotropic expansion of the gas is interpreted by collisional hydrodynamics. We observe an unexpected and large shift ($80 $G) between the resonance peak and both the maximum of atom loss and the change of sign of the interaction energy.

  20. Understanding the effect of channel coupling on fusion of 6Li+64Ni

    Science.gov (United States)

    Moin Shaikh, Md.; Roy, Subinit

    2016-07-01

    The effect of inelastic excitation and single particle transfer reactions on fusion have been investigated for the system 6Li+64Ni at near barrier energies. The calculations show that a simultaneous coupling to the inelastic excitation of projectile and target along with positive Q-value 1n- and 1p-stripping channels, describes the experimental CF cross sections reasonably well in the below barrier region.

  1. Design of a 7Li rotating target for neutron production using a Van de Graaff accelerator

    International Nuclear Information System (INIS)

    We present a rotating target used for the production of monokinetic neutron fluxes. The neutrons are produced from the 7Li(p,n)7Be reaction for fast neutron elastic and inelastic scattering experiments. This target has been operated with a proton beam current of 8 to 10 μA during six consecutive weeks and has given entire satisfaction

  2. Elastic break-up of 156 MeV 6Li projectiles with large asymptotic relative momenta of the fragments

    International Nuclear Information System (INIS)

    The triple differential cross sections for elastic break-up of 156 MeV 6Li projectiles by the reactions 208Pb (6Li, ad) 208Pbg.s., and 12C (6Li, ad) 12Cg.s. have been measured with large asymptotic relative momenta of the outgoing fragments. The data exhibit rather unfamiliar shapes of the energy spectra, often replacing the usual bell-shape distributions by double-peaked structures and varying rapidly with the relative emission angles. The origin of these features has been explored and the cross sections have been analysed on the basis of a diffractive disintegration approach. (orig.)

  3. Evaluation of d + 6,7Li data for deuteron incident energies up to 50 MeV

    International Nuclear Information System (INIS)

    A new evaluation of the nuclear data for a particle transport calculations was performed for d + 6,7Li interactions in the energy region from 4 to 50 MeV incident energy. Use was made of the available new optical model potential for d + Li interactions. For the description of a neutron emission a new optical model potential for n + 9Be was elaborated for the neutron energies from 0.1 to 22 MeV. Global optical model potentials were used for the neutrons above 22 MeV and for protons, tritons, He-3 and alphas - in the whole energy range. The following nuclear processes were accounted for: particle evaporation and preequilibrium emission, stripping of the proton from the deuteron and direct interactions of deuterons with lithium nuclei. GNASH and ECIS96 codes were applied for the first two process descriptions, the Serber model was utilised for stripping processes and the DWUCK4 code was used for direct reaction processes modelling. Total neutron emission spectra were calculated as a sum of the spectra in all these processes. A complete transport file was finally prepared in ENDF-6 format covering the deuteron incident energies up to 50 MeV. The newly evaluated data are in good agreement with experimental data for neutron emission spectra. The evaluated data files were successfully tested with a modified version of the MCNP computer code

  4. Neutron detector based on Particles of 6Li glass scintillator dispersed in organic lightguide matrix

    International Nuclear Information System (INIS)

    Most 3He replacement neutron detector technologies today have overlapping neutron–gamma pulse-height distributions, which limits their usefulness and performance. Different techniques are used to mitigate this shortcoming, including Pulse Shape Discrimination (PSD) or threshold settings that suppress all gammas as well as much of the neutrons. As a result, count rates are limited and dead times are high when PSD is used, and the detection efficiency for neutron events is reduced due to the high threshold. This is a problem in most applications where the neutron–gamma separation of 3He detectors had been essential. This challenge is especially severe for neutron coincidence and multiplicity measurements that have numerous conflicting requirements such as high detection efficiency, short die-away time, short dead time, and high stability. 6Li-glass scintillators have excellent light output and a single peak distribution, but they are difficult to implement because of their gamma sensitivity. The idea of reducing the gamma sensitivity of 6Li-glass scintillators by embedding small glass particles in an organic light-guide medium was first presented by L.M. Bollinger in the early 60s but, to the best of our knowledge, has never been reduced to practice. We present a proof of principle detector design and experimental data that develop this concept to a large-area neutron detector. This is achieved by using a multi-component optical medium (6Li glass particles attached to a glass supporting structure and a mineral oil light guide) which matches the indices of refraction and minimizes the absorption of the 395 nm scintillator light. The detector design comprises a 10 in. long tube with dual end readout with about 3% volume density of 6Li glass particles installed. The presented experimental data with various neutron and gamma sources show the desired wide gap between the neutron and gamma pulse height distributions, resulting in a true plateau in the counting

  5. 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.

  6. 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.``

  7. Elastic scattering for the system {sup 6}Li+p at near barrier energies with MAGNEX

    Energy Technology Data Exchange (ETDEWEB)

    Soukeras, V.; Pakou, A.; Sgouros, O. [Department of Physics and HINP, The University of Ioannina, 45110 Ioannina (Greece); Cappuzzello, F.; Bondi, M.; Nicolosi, D. [INFN Laboratory Nazionali del Sud, via S. Sofia 62, 95125, Catania, Italy and Dipartimento di Fisica e Astronomia, Universita di Catania, via S. Sofia 64, 95125, Catania (Italy); Acosta, L.; Marquinez-Duran, G.; Martel, I. [Departamento di Fisica Aplicada, Universidad de Huelva, E-21071, Huelva (Spain); Agodi, C.; Carbone, D.; Cavallaro, M.; Cunsolo, A.; Di Pietro, A.; Fernández-García, J. P.; Figuera, P.; Fisichella, M. [INFN Laboratory Nazionali del Sud, via S. Sofia 62, 95125, Catania (Italy); Alamanos, N. [CEA-Saclay, DAPNIA-SPhN, 91191, Gif-sur-Yvette (France); De Napoli, M. [INFN - Sezione di Catania, via S. Sofia 64, 95125, Catania (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, via S. Sofia 64, 95125, Catania, Italy and INFN - Sezione di Catania, via S. Sofia 64, 95125, Catania (Italy); and others

    2015-02-24

    Elastic scattering measurements have been performed for the {sup 6}Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼2{sup 0} and 12{sup 0} in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies.

  8. Reexamining closed-form formulae for inclusive breakup: Application to deuteron and $^6$Li induced reactions

    CERN Document Server

    Lei, Jin

    2015-01-01

    The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern and Vincent [Phys. Rev. C32, 431 (1985) is revisited, and an alternative derivation of the non-elastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the DWBA version of this model, several applications to deuteron and $^6$Li reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculations.

  9. 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.

  10. 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.

  11. The scattering of 136 MeV protons from 6Li

    International Nuclear Information System (INIS)

    Differential cross sections have been measured for the elastic scattering of 136 MeV protons from 6Li, and for inelastic scattering to the first two excited states. The optical model fit to the elastic scattering differential cross section gave parameters which were retained for the analysis of the two inelastic transitions. The latter differential cross sections were fairly well fitted in shape, but in both cases there is a discrepancy in absolute magnitude of a factor between 1.5 and 4

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

    OpenAIRE

    Xu, Ming; Tang, Zhi-Cheng; 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 eac...

  13. Probing transfer to unbound states of the ejectile with weakly bound 7Li on 93Nb

    CERN Document Server

    Pandit, S K; Mahata, K; Keeley, N; Parkar, V V; Rout, P C; Martel, I; Palshetkar, C S; Kumar, A; Ramachandran, K; Patale, P; Chatterjee, A; Kailas, S

    2016-01-01

    The two-step process of transfer followed by breakup is explored by measuring a rather complete set of exclusive data for reaction channels populating states in the ejectile continua of the $^7$Li+$^{93}$Nb system at energies close to the Coulomb barrier. The cross sections for $\\alpha+\\alpha$ events from one proton pickup were found to be smaller than those for $\\alpha+d$ events from one neutron stripping and $\\alpha+t$ events from direct breakup of $^7$Li. Coupled channels Born approximation and continuum discretized coupled channels calculations describe the data well and support the conclusion that the $\\alpha+d$ and $\\alpha+\\alpha$ events are produced by direct transfer to unbound states of the ejectile.

  14. New measurement of the 10B(n,α)7 Li through the Trojan Horse Method

    Science.gov (United States)

    Spartá, Roberta

    2016-04-01

    B(n,α) Li reaction cross section has been measured using the Trojan Horse method, with the specific aim to separate the α1 contribution (coming from the first Li excited level) by the αo (related to the Li ground state), using a very thin target. Preliminary results are shown of the three-body B(d,α7 Li)H cross section.

  15. Impact of alternate fusion fuels on fusion reactor technology: an initial assessment study. [Catalyzed D, D-/sup 3/He, p-/sup 6/Li, p-/sup 7/Li, D-/sup 6/Li, p-/sup 11/B, /sup 3/He-/sup 3/He

    Energy Technology Data Exchange (ETDEWEB)

    Baker, C.C.; Bolon, A.; Clemmer, R.

    1979-11-01

    The initial results of a study carried out to assess some of the technology implications of non-D-T fusion fuel cycles are presented. The primary emphasis in this report is on D-D, catalyzed-D and D-/sup 3/He fuel cycles. Tokamaks and field-reversed mirrors have been selected as sample confinement concepts. A new technique of employing neutronic computer codes to study the transport of cyclotron radiation for cases of non-uniform density and temperature profiles is described. The technology areas considered include first wall design considerations, shielding requirements, fuel cycle requirements and some safety and environmental considerations. Conclusions resulting from the study are also presented.

  16. 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...

  17. Measuring the absorption mean cross section in 6Li relative to 235U fission

    International Nuclear Information System (INIS)

    Due to the fact that the neutron absorption cross section in 6Li is used as one of standards for determinaton of neutron-physical characteristics of fast reactors the ratio of mean cross sections for absorption by 6Li (A6) and 235U fission F25 are experimentalli investigated. The measurements have been performed in the KBR-8, KBR-10,BFS/39/1 bfs-44, BFS/45a-1 and BFS-46 critical assemblies which are characterized by various neutron spectra by means of a lithium counter with semiconductor detectors. Ratios A6/F25 for investigated assemblies constituted respectively 0.605+-0.009; 0.604+-0.004; 0.581+-0.009; 0.590+-0.574+-0.005. The values of 235U diffusion mean cross sections obtained on the base of these fata and calculated using the CRAB-1 program (given in brackets) are equal respectively 1.53+-0.005 (1.51) 2.38+-0.08 (2.42); 1.935+-0.060 (1.95); 1.89+-0.08 (1.95); 1.780+-0.11 (1.69); 1.90+-0.06 (1.89)

  18. Detection efficiency simulation and measurement of 6LiI/natLiI scintillation detector

    International Nuclear Information System (INIS)

    Background: Being of very high detection efficiency and small size, Lithium iodide (LiI) scintillator detector is used extensively in neutron measurement and environmental monitoring. Purpose: Using thermal reactor, neutron detectors will be tested and calibrated. And a new neutron detector device will be designed and studied. Methods: The relationship between the size and detection efficiency of the thermal neutron detector 6LiI/natLil was studied using Monte Carlo code GEANT4 and MCNP5 package, and the thermal neutron efficiency of detector was calibrated by reactor neutrons. Results: The theoretical simulation shows that the thermal neutron detection efficiency of detector of 10-mm thickness is relatively high, the enriched 6Lil is up to 98% and the nature natLiI 65%. The thermal neutron efficiency of detector is calibrated by reactor thermal neutrons. Considering the neutron scattering by the lead brick, high density polythene and environment neutron contribution, the detection efficiency of 6LiI detector is about 90% and natLiI detector 70%. Conclusion: The detector efficiency can reach the efficiency value of theoretical calculations. (authors)

  19. Exploring an ultracold Fermi-Fermi mixture: interspecies Feshbach resonances of ^6Li-^40K

    Science.gov (United States)

    Schreck, Florian

    2008-03-01

    We report on the observation of interspecies Feshbach resonances in an ultracold mixture of two fermionic species, ^6Li and ^40K. Interpretation of the data unambiguously assigns molecular bound states to the various resonances and fully characterizes the ground-state scattering properties in any combination of spin states. Using this knowledge we hope to be able to produce ^6Li-^40K molecules, cool them to quantum degeneracy, and study their BEC-BCS crossover. In collaboration with: F. Schreck, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; E. Wille, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; F.M. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; R. Grimm, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; T.G. Tiecke, J.T.M. Walraven,Van der Waals-Zeeman Institute of the University of Amsterdam, 1018 XE, The Netherlands; S.J.J.M.F. Kokkelmans, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; E. Tiesinga, P.S. Julienne, Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899-8423, USA

  20. Neutron Energy Spectra and Yields from the 7Li(p,n) Reaction for Nuclear Astrophysics

    Science.gov (United States)

    Tessler, M.; Friedman, M.; Schmidt, S.; Shor, A.; Berkovits, D.; Cohen, D.; Feinberg, G.; Fiebiger, S.; Krása, A.; Paul, M.; Plag, R.; Plompen, A.; Reifarth, R.

    2016-01-01

    Neutrons produced by the 7Li(p, n)7Be reaction close to threshold are widely used to measure the cross section of s-process nucleosynthesis reactions. While experiments have been performed so far with Van de Graaff accelerators, the use of RF accelerators with higher intensities is planned to enable investigations on radioactive isotopes. In parallel, high-power Li targets for the production of high-intensity neutrons at stellar energies are developed at Goethe University (Frankfurt, Germany) and SARAF (Soreq NRC, Israel). However, such setups pose severe challenges for the measurement of the proton beam intensity or the neutron fluence. In order to develop appropriate methods, we studied in detail the neutron energy distribution and intensity produced by the thick-target 7Li(p,n)7Be reaction and compared them to state-of- the-art simulation codes. Measurements were performed with the bunched and chopped proton beam at the Van de Graaff facility of the Institute for Reference Materials and Measurements (IRMM) using the time-of-flight (TOF) technique with thin (1/8") and thick (1") detectors. The importance of detailed simulations of the detector structure and geometry for the conversion of TOF to a neutron energy is stressed. The measured neutron spectra are consistent with those previously reported and agree well with Monte Carlo simulations that include experimentally determined 7Li(p,n) cross sections, two-body kinematics and proton energy loss in the Li-target.

  1. In-beam PET measurement of $^{7}Li^{3+}$ irradiation induced $\\beta^+}$-activity

    CERN Document Server

    Priegnitz, M; Parodi, K; Sommerer, F; Fiedler, F; Enghardt, W

    2008-01-01

    At present positron emission tomography (PET) is the only feasible method of an in situ and non-invasive monitoring of patient irradiation with ions. At the experimental carbon ion treatment facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt an in-beam PET scanner has been integrated into the treatment site and lead to a considerable quality improvement of the therapy. Since ions other than carbon are expected to come into operation in future patient treatment facilities, it is highly desirable to extend in-beam PET also to other therapeutic relevant ions, e.g. 7Li. Therefore, by means of the in-beam PET scanner at GSI the β+-activity induced by 7Li3+ ions has been investigated for the first time. Targets of PMMA, water, graphite and polyethylene were irradiated with monoenergetic, pencil-like beams of 7Li3+ with energies between 129.1 A MeV and 205.3 A MeV and intensities ranging from 3.0 × 107 to 1.9 × 108 ions s−1. This paper presents the measured β+-activity profiles as well as d...

  2. The 3H(α,γ)7Li reaction at low energies

    International Nuclear Information System (INIS)

    The 3H(α,γ) reaction, and its mirror 3He(α,γ) are responsible for 7Li production in the big bang. Discrepancies between experimental data sets, as well as differences between the experimental and theoretical energy dependences, cause the 3H(α,γ)7Li cross section to be uncertain by as much as a factor of two at the relevant astrophysical energies (Ec.m. ∼ 100 keV). The authors report new measurements for 50 c.m. 3H targets and an 85% high-purity germanium detector. Angular distributions were measured at nine energies between 115 and 1200 kev. The astrophysical S-factor is observed to increase moderately with decreasing energy to S(0) ∼ 0.10 keV-b. The branching ratio for captures to the first excited state and ground state of 7Li is found to be ∼0.44, independent of energy. The results are compared to previous experiments and theoretical calculations

  3. Electron affinity of (7)Li calculated with the inclusion of nuclear motion and relativistic corrections.

    Science.gov (United States)

    Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik

    2007-10-01

    Explicitly correlated Gaussian functions have been used to perform very accurate variational calculations for the ground states of (7)Li and (7)Li(-). The nuclear motion has been explicitly included in the calculations (i.e., they have been done without assuming the Born-Oppenheimer (BO) approximation). An approach based on the analytical energy gradient calculated with respect to the Gaussian exponential parameters was employed. This led to a noticeable improvement of the previously determined variational upper bound to the nonrelativistic energy of Li(-). The Li energy obtained in the calculations matches those of the most accurate results obtained with Hylleraas functions. The finite-mass (non-BO) wave functions were used to calculate the alpha(2) relativistic corrections (alpha=1c). With those corrections and the alpha(3) and alpha(4) corrections taken from Pachucki and Komasa [J. Chem. Phys. 125, 204304 (2006)], the electron affinity (EA) of (7)Li was determined. It agrees very well with the most recent experimental EA. PMID:17919011

  4. An Updated 6Li(p, α)3He Reaction Rate at Astrophysical Energies with the Trojan Horse Method

    Science.gov (United States)

    Lamia, L.; Spitaleri, C.; Pizzone, R. G.; Tognelli, E.; Tumino, A.; Degl'Innocenti, S.; Prada Moroni, P. G.; La Cognata, M.; Pappalardo, L.; Sergi, M. L.

    2013-05-01

    The lithium problem influencing primordial and stellar nucleosynthesis is one of the most interesting unsolved issues in astrophysics. 6Li 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 6Li ignition temperature. Thus, gaining an understanding of 6Li 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, Ue . Thanks to recent direct measurements, new estimates of the 6Li(p, α)3He bare-nucleus S(E) factor and the corresponding Ue value have been obtained by applying the Trojan Horse method to the 2H(6Li, α 3He)n reaction in quasi-free kinematics. The calculated reaction rate covers the temperature window 0.01 to 2T 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.

  5. Use of {sup 7}Li(p,n) reaction as a neutron source in a PGNAA setup

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Box No. 1815, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Box No. 1815, Dhahran 31261 (Saudi Arabia)

    2005-03-01

    The performance of a {sup 7}Li(p,n) reaction-based Prompt Gamma Ray Neutron Activation Analysis (PGNAA) setup has been determined for analysis of Portland cement samples using Monte Carlo study. The calculations were carried out for a {sup 7}Li(p,n) reaction-based PGNAA setup with an external moderator similar to the one used in a previous 2.8 MeV neutrons-based PGNAA setup. The optimum values of geometry parameters of the {sup 7}Li(p,n) reaction-based setup are different from those of the 2.8 MeV neutrons-based setup resulting in better performance of the {sup 7}Li(p,n) reaction-based setup. The prompt {gamma}-ray yield from the {sup 7}Li(p,n) reaction-based setup is 60-70% higher than that from the 2.8 MeV neutrons-based setup. Although the performances of the {sup 7}Li(p,n) reaction-based setup is comparable with that of a previously studied {sup 3}H(p,n) reaction-based setup, yet performance of the {sup 7}Li(p,n) reaction-based setup is superior to that of the {sup 3}H(p,n) reaction-based setup because it has less radiation hazard due to utilization of non-radioactive neutron producing target. This study has provided a theoretical base for experimental test of a {sup 7}Li(p,n) reaction-based PGNAA setup.

  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. 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.

  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. 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.

  10. Study of reaction products of d + 6Li at 0,18 MeV

    International Nuclear Information System (INIS)

    The study of continuous spectra of low energy particles, and more particularly of their shape and intensity allows a better understanding and knowledge of the structure of nuclei as they interact when encountering. As previous studies performed in Saclay had been interpreted by introducing the new notions of nuclear molecule or activated complex followed by a dissymmetric breaking, and in order to better understand the formation of these molecules, this research thesis reports the study of the d + 6Li reaction at 0,18 MeV. After a description of the experimental installation and of the processing of nuclear emulsions, the author presents and discusses the obtained results and calculations resulting from the fact that the different particles cannot be discriminated in the continuum. Theoretical results for the continuous spectrum are compared with experimental results, and the author reports angular distributions of alpha particles and p0 and p1 protons

  11. 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)

  12. 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.

  13. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D.; Reyna, David; Monahan, James; Bowden, Nathaniel S.

    2010-11-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  14. Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D.; Reyna, David; Monahan, James (Drexel University, Philadelphia, PA); Bowden, Nathaniel S. (Lawrence Livermore National Laboratory, Livermore, CA)

    2010-10-01

    Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/{sup 6}LiF configurations reliably identify {sup 6}Li neutron captures in 60 cm-long segments using pulse shape discrimination.

  15. 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 .

  16. Investigations of 6LiIn1-xGaxSe2 semi-insulating crystals for neutron detection

    Science.gov (United States)

    Wiggins, Brenden; Bell, Joseph; Burger, Arnold; Stassun, Keivan; Stowe, Ashley C.

    2015-08-01

    Neutron detectors are used for illicit material detection, neutron radiography, stellar investigations of chemical content including biological compounds in planetary terrain and to monitor nuclear power plant fuel products and radioactive waste. Li-containing chalcogenide materials are promising alternative thermal neutron detection materials due to the incorporation of the 6Li isotope at high density. 6LiInSe2 is limited in its effective thermal neutron efficiency by 115In neutron capture which results in gamma decay rather than charge creation. This study includes investigations of mixed crystalline material 6LiIn1-xGaxSe2 where the indium concentration is reduced by Ga substitution. The optical properties have been tuned by gallium substitution and radiation response has been observed.

  17. Double-folding analysis of the 6Li + 58Ni reaction using the ab initio density distribution

    International Nuclear Information System (INIS)

    The elastic scattering angular distributions of the 6 Li + 58 Ni reaction are reanalyzed by using the double-folding model (DFM) within the framework of the optical model (OM) at energies near the Coulomb barrier, ELab = 9.9, 11.2, 12.1, 13.0 and 14.0 MeV. With this goal, for the first time, the no-core full configuration (NCFC) density distribution (DD) of the 6 Li nucleus is used in order to obtain the real potentials. Also, in order to see the validity of NCFC DD, another density distribution (Gaussian shape) of the 6 Li nucleus is used to obtain the real potentials in DF calculations. The results with NCFC DD are compared with Gaussian shape (GS) DD as well as the experimental data. It has been seen that the NCFC DD results are in agreement with the experimental data, giving better results than GS DD. (orig.)

  18. Phenomenological and microscopic optical potentials for 88 MeV 7Li scattering

    International Nuclear Information System (INIS)

    The elastic scattering cross sections for 88 MeV 7Li ions have been measured for targets of 2426Mg and 4048Ca. Analyses using both phenomenological and microscopic optical potentials provide information on the energy dependence of optical parameters, and the extent to which the potentials are determined for these light ions. The use of a double-folding microscopic model demonstrates the need for normalisation of the real potential by a factor of 0.5 in contrast to measurements at lower energies. The contribution of exchange effects, density dependence and break-up are discussed. (author)

  19. Angular Distribution of the 12C(6He, 7Li)11B Reaction

    Institute of Scientific and Technical Information of China (English)

    LI Er-Tao; LI Zhi-Hong; LI Yun-Ju; YAN Sheng-Quan; BAI Xi-Xiang; GUO Bing; SU Jun; WANG You-Bao; WANG Bao-Xiang; LIAN Gang; ZENG Sheng; FANG Xiao; ZHAO Wei-Juan; LIU Wei-Ping

    2009-01-01

    Angular distribution of the 12C(6He, 7Li)11B transfer reaction is measured with a secondary 6He beam of 36.4 Me V for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approxima-tion (DWBA) calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), Beifing.

  20. 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%.

  1. Multi-elemental characterization of organic liquid samples by use of a 13 MeV 6Li3+ beam

    International Nuclear Information System (INIS)

    Evaporated amniotic fluid (AF) targets have been bombarded with a 13 MeV 6Li3+ beam. Forward angle data have served to identify the 1H(6Li,1H)6Li reaction as an alternative for hydrogen characterization of such organic samples. Detected 6Li 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.

  2. T sub 20 in the inclusive breakup of 4. 5 GeV polarized sup 6 Li

    Energy Technology Data Exchange (ETDEWEB)

    Punjabi, V. (Norfolk State University, Norfolk, Virginia 23504 (United States)); Perdrisat, C.F.; Cheung, E. (The College of William and Mary, Williamsburg, Virginia 23185 (United States)); Yonnet, J.; Boivin, M.; Tomasi-Gustafsson, E. (Laboratoire National Saturne, Centre d' Etudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette (France)); Siebert, R.; Frascaria, R.; Warde, E. (Institut de Physique Nucleaire, Universite Paris 13, Orsay (France)); Belostotsky, S.; Miklucho, O.; Sulimov, V. (Leningrad Institute for Nuclear Physics, Gatchina (Russia)); Abegg, R. (TRIUMF, Vancouver, British Columbia, Canada V6T 1W5 and University of Alberta, Edmonton, T6G 2J1 (Canada)); Lehman, D.R. (The George Washington University, Washington, D.C. 20052 (United States))

    1992-09-01

    The analyzing power {ital T}{sub 20} in the inclusive {sup 1}H({sup 6}Li,{ital d} or {alpha} or {ital t}){ital X} reaction with 4.5 GeV tensor polarized {sup 6}Li nuclei has been measured at an angle of 0.8{degree}. The kinematics chosen favor the detection of spectator fragments; in the impulse approximation the laboratory momentum of such a fragment is then the Lorentz boosted internal momentum. Nonzero {ital T}{sub 20} values have been observed, in agreement with the known nonsphericity of {sup 6}Li indicated by its quadrupole moment. The sign of {ital T}{sub 20} in the {ital d} channel suggests that near {ital q}=0 the {ital D} state in {sup 6}Li has the same sign as in the deuteron; an abrupt change of sign near {ital q}=0.12 GeV/{ital c} is in agreement with theoretical expectation of a node in the {alpha}{ital d} position wave function. The {alpha}-channel data show larger {ital T}{sub 20} values than the {ital d} channel; in this case the small-{ital q}-region has not been explored enough to establish a similar node. A few data points in the {ital t} channel might suggest that {ital T}{sub 20} becomes positive above {ital q}=0.4 GeV/{ital c} in this case.

  3. A SiPM-based ZnS:$^6$LiF scintillation neutron detector

    CERN Document Server

    Stoykov, A; Greuter, U; Hildebrandt, M; Schlumpf, N

    2014-01-01

    In the work presented here we built and evaluated a single-channel neutron detection unit consisting of a ZnS:$^6$LiF scintillator with embedded WLS fibers readout by a SiPM. The unit has a sensitive volume of 2.4 x 2.8 x 50 mm$^3$; 12 WLS fibers of diameter 0.25 mm are uniformly distributed over this volume and are coupled to a 1 x 1 mm$^2$ active area SiPM. We report the following performance parameters: neutron detection efficiency $\\sim 65\\,$% at $1.2\\,\\AA$, background count rate $< 10^{-3}$ Hz, gamma-sensitivity with $^{60}$Co source $< 10^{-6}$, dead time $\\sim 20\\,\\mu$s, multi-count ratio $< 1\\,$%. All these parameters were achieved up to the SiPM dark count rate of $\\sim 2\\,$MHz. We consider such detection unit as an elementary building block for realization of one-dimensional multichannel detectors for applications in the neutron scattering experimental technique. The dimensions of the unit and the number of embedded fibers can be varied to meet the specific application requirements. The upp...

  4. Neutron total and scattering cross sections of 6Li in the few MeV region

    International Nuclear Information System (INIS)

    Neutron total cross sections of 6Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of approx. 10 scattering angles and at incident-neutron intervals of approx.< 100 keV. Neutron differential inelastic-scattering cross sections are measured in the incident-energy range 3.5 to 4.0 MeV. The experimental results are extended to lower energies using measured neutron total cross sections recently reported elsewhere by the authors. The composite experimental data (total cross sections from 0.1 to 4.8 MeV and scattering cross sections from 0.22 to 4.0 MeV) are interpreted in terms of a simple two-level R-matrix model which describes the observed cross sections and implies the reaction cross section in unobserved channels; notably the (n;α)t reaction (Q = 4.783 MeV). The experimental and calculational results are compared with previously reported results as summarized in the ENDF/B-V evaluated nuclear data file

  5. Analysis of 6Li Scattering at 240 MeV Using Different Nuclear Potentials

    Science.gov (United States)

    Al-Ghamdi, A. H.; Ibraheem, Awad A.

    2016-06-01

    Angular distributions of the elastic and inelastic scattering cross sections of 6Li projectile on different heavy ion target nuclei including the 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn at energy of 240 MeV have been analyzed by using two different folded potentials based on the CDM3Y6 and São Paulo potentials for the real part of the optical potential, while the imaginary parts have a phenomenological Woods-Saxon shape. Coupled channel calculations for the low-lying 2+ state at 1.369, 1.779, 3.832, 1.454, 2.186, and 1.29 MeV for 24Mg, 28Si, 48Ca, 58Ni, 90Zr, and 116Sn, respectively, have been carried out, and the best fit values for B(EL) with the above models have been extracted by fitting the inelastic scattering cross section and compared with the values of previous works. The total reaction cross section and real and imaginary volume integrals have also been investigated.

  6. MCNP6 Simulation of Quasi-Monoenergetic 7Li(p,n) Neutron Sources below 150 MeV

    CERN Document Server

    Mashnik, Stepan G

    2013-01-01

    The applicability of MCNP6 to simulate quasi-monoenergetic neutron sources from interactions of proton beams with energies below 150 MeV on thick 7Li targets have been studied. Neutron spectra at zero degrees from a 2-mm 7Li layer backed by a 12-mm carbon beam stopper in an Al flange bombarded with protons of 20, 25, 30, 35, and 40 MeV have been calculated with MCNP6 using the recent Los Alamos data library as well as using the Bertini+Dresner and CEM03.03 event generators. A comparison with the experimental neutron spectra shows that the event generators do not do well in describing such reactions, while MCNP6 using the LANL data library simulates production of neutrons from p + 7Li in good agreement with the measured data.

  7. Covariance analysis of n + 7Li data for ENDF/B-VI

    International Nuclear Information System (INIS)

    A new covariance analysis of n/plus/7Li experimental data has been completed for Version VI of ENDFB. The analysis basically updates our 1981 work for ENDFB-V.2 to include new data that has become available since that time and to incorporate cross correlations between different experiments. The bulk of the new measured data consists of some 10 new (or newly revised) tritium-production measurements involving about 70 new data points. The new analysis results in only small changes in the previous evaluation of the tritium-production cross section but significantly reduces the magnitudes of uncertainties due to the more extensive and accurate data base that was used

  8. Photoassociation and ionization spectroscopy of ultracold $^{7}$Li$^{85}$Rb molecules

    CERN Document Server

    Altaf, Adeel; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S

    2014-01-01

    We report spectroscopic studies of ultracold $^{7}$Li$^{85}$Rb molecules using multiphoton ionization detection. With our dual-species Li and Rb MOT apparatus, we create ultracold LiRb molecules via photoassociation (PA), and explore new PA resonances, with binding energies up to ~62 cm^{-1}. Furthermore, we measure the resonantly enhanced multiphoton ionization (REMPI) spectra as a probe of ground and excited state vibrational levels. We identify vibrational levels of the $a^{3}\\Sigma^{+} (v" = 7 - 13)$, $3^{3} \\Pi (v'_{\\Pi} = 0 - 10)$ and $4^{3} \\Sigma^{+} (v'_{\\Sigma} = 0 - 5)$ electronic states. Our line assignments agree well with ab initio calculations. These spectroscopic studies are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state.

  9. Dynamics of fragment capture for cluster structures of weakly bound 7Li

    Directory of Open Access Journals (Sweden)

    Shrivastava A.

    2013-12-01

    Full Text Available Role of cluster structures of 7Li on reaction dynamics have been studied by performing exclusive measurements of prompt-γ rays from residues with scattered particles at energy, E/Vb = 1.6, with 198Pt target. Yields of the residues resulting after capture of t and 4,5,6He, corresponding to different excitation energies of the composite system were estimated. The results were compared with three body classical-dynamical model for breakup fusion, constrained by the measured fusion, α and t capture cross-sections. The cross-section of residues from capture of α and t agreed well with the prediction of the model showing dominance of the two step process - breakup fusion, while those from tightly bound 6He showed massive transfer to be the dominant mechanism.

  10. Study of the {sup 7}Li (p,{alpha}){sup 4}He Reaction at Astrophysical Energies Through the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Pellegriti, M.G.; Aliotta, M.; Cherubini, S.; Lattuada, M.; Miljanic, D.; Pizzone, R.G.; Romano, S.; Soic, N.; Spitaleri, C.; Zadro, M.; Zappala, R.A.

    2000-12-31

    The Trojan Horse Method has been applied to obtain information about {sup 7}Li(p,{alpha}),{sup 4}He reaction at astrophysical energies. The {sup 7}Li(d,{alpha} n){sup 4}He reaction has been used and the two body reaction cross section for the {sup 7}Li(p,{alpha}){sup 4}He has been extracted together with its astrophysical factor S(E).

  11. 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

  12. 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.

  13. 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.

  14. Precise determination of 6Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules

    International Nuclear Information System (INIS)

    We employ radio-frequency spectroscopy on weakly bound 6Li2 molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold 6Li atoms based on a multichannel quantum scattering model. We determine the singlet and triplet scattering lengths to be as=45.167(8)a0 and at=-2140(18)a0 (1a0=0.052 917 7 nm), and the positions of the broad Feshbach resonances in the energetically lowest three s-wave scattering channels to be 83.41(15), 69.04(5), and 81.12(10) mT

  15. 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.

  16. 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.

  17. Comparison of thermal neutron detection efficiency of 6Li scintillation glass and 3He gas proportional tube

    International Nuclear Information System (INIS)

    We report on a comparison study of the 3He gas proportional tube and the 6Li incorporated scintillation glasses on thermal neutron detection efficiency. Both 3He and 6Li are used commonly for thermal neutron detection because of their high neutron capture absorption coefficient. By using a neutron source 252Cf 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 has been modeled with GEANT4 to validate the results against the Monte Carlo simulation. (authors)

  18. Neutron detection and identification using ZnS:Ag/{sup 6}LiF in segmented antineutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kiff, Scott D., E-mail: skiff@sandia.gov [Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94550 (United States); Bowden, Nathaniel [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Lund, Jim; Reyna, David [Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94550 (United States)

    2011-10-01

    Antineutrino detection using inverse beta-decay conversion has demonstrated capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which a successful background rejection strategy will be needed to measure the anticipated antineutrino event rates. In this paper, we report on initial studies to quantify the intrinsic capture efficiency and particle identification capabilities of a new scintillation-based segmented design that uses layers of ZnS:Ag/{sup 6}LiF to capture and identify neutrons created in the inverse beta-decay reaction. Laboratory efficiency measurements are consistent with MCNP5 calculations, estimating {sup 6}Li neutron conversion efficiency above 50% for practical full-scale detector configurations.

  19. Influence of the separation of the centre-of-mass motion on the charge form factor of /sup 6/Li

    Energy Technology Data Exchange (ETDEWEB)

    Bouten, M. (Limburgs Universitair Centrum (Belgium)); Bouten, M.C. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium))

    1982-12-01

    An exact calculation is carried out for the charge form factor of /sup 6/Li using a wavefunction for the ground state which depends on the internal coordinates only and which contains a short-range correlation factor of the Jastrow type. A very good fit to the experimental data can be obtained by adjusting the parameters in the wavefunction. It is found that the optimum value of these parameters depends sensitively on the way the centre-of-mass coordinate is eliminated.

  20. Examination of the Coulomb-nuclear interference in inelastic scattering of 6Li in 76Ge

    International Nuclear Information System (INIS)

    The inelastic scattering of 28,0 MeV 6Li on 76Ge in the excitation of the 2+1 state, has been studied with the Coulomb-Nuclear Interference (CNI) analysis. The data were measured at the Pelletron-Enge-Spectrograph facility at LAFN-IFUSP. A solid-state position sensitive silicon detector (PSD) (500μm thickness and 47 × 8 mm2 area) was used to measure the data at the spectrometer focal plane. Digital pulse processing (DPP) was implemented in the acquisition system. Twenty-six spectra were measured at carefully chosen scattering angles in the range of 10 deg ≤ θLab ≤ 55 deg to obtain an angular distribution. The analysis was performed with the Distorted Wave Born Approximation (DWBA) and applied for the nuclear transition potential, the Deformed Optical Potential Model (DOMP), under well-established global optical parameters. The fit of the predicted cross sections to the experimental data through χ2 minimization, using the iterative method of Gauss, allowed for the extraction of the correlated parameters, δN2, the mass deformation length, and C2 = ΝC2/δN2, the ratio between charge and mass deformation lengths. The correlated parameters obtained in the present work were C2 = 1,101 (20) and δN2 = 1,08(21)fm. Statistical tests, through a Monte Carlo simulation of 5000 new data sets, validated the method employed in the correlated parameters fit. The methodology applied for the CNI analysis allowed the extraction of ratio B(EL)/B(ISL), which is proportional to the square of C2, with a good precision due to the scale uncertainties cancellation of the absolute cross sections. The values of B(IS2) and of the ratios B(E2)/B(IS2) obtained in the present work have not been reported before and allow the study of the evolution of the collectivity throughout the even-A germanium chain together with former results obtained for the 70,72,74Ge isotopes. The results along the chain indicate that although the protons relative to the neutrons reveal a small predominant

  1. 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.

  2. Cross Section Measurement of 9Be(\\gamma,n)8Be and Implications for \\alpha+\\alpha+n -> 9Be in the r-Process

    CERN Document Server

    Arnold, C W; Iliadis, C; Karwowski, H J; Rich, G C; Tompkins, J R; Howell, C R

    2011-01-01

    Models of the r-process are sensitive to the production rate of 9Be because, in explosive environments rich in neutrons, \\alpha(\\alpha n,\\gamma)9Be is the primary mechanism for bridging the stability gaps at A=5 and A=8. The \\alpha(\\alpha n,\\gamma)9Be reaction represents a two-step process, consisting of \\alpha+\\alpha -> 8Be followed by 8Be(n,\\gamma)9Be. We report here on a new absolute cross section measurement for the 9Be(\\gamma,n)8Be reaction conducted using a highly-efficient, 3He-based neutron detector and nearly-monoenergetic photon beams, covering energies from E_\\gamma = 1.5 MeV to 5.2 MeV, produced by the High Intensity \\gamma-ray Source of Triangle Universities Nuclear Laboratory. In the astrophysically important threshold energy region, the present cross sections are 40% larger than those found in most previous measurements and are accurate to +/- 10% (95% confidence). The revised thermonuclear \\alpha(\\alpha n,\\gamma)9Be reaction rate could have implications for the r-process in explosive environme...

  3. Validity test of the Trojan Horse Method applied to the {sup 7}Li+p{yields} {alpha}+{alpha} reaction via the {sup 3}He break-up

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Sergi, M.L.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Tudisco, S. [Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Kroha, V.; Burjan, V.; Novac, J.; Vincour, J. [Nuclear Physics Institute of ASCR, Rez, Prague (Czech Republic); Fueloep, Z.; Somorjai, E. [Institute of Nuclear Research of Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Pizzone, R.G. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method (THM) was applied to the {sup 3}He+{sup 7}Li interaction in order to investigate the quasi-free {sup 7}Li(p,{alpha}){sup 4}He reaction. The three-body experiment was performed at 33 MeV corresponding to a {sup 7}Li-p relative energy ranging from 50 keV to 7 MeV. The extracted {sup 7}Li(p,{alpha}){sup 4}He quasi-free cross-section was compared with the behavior of direct data, as well as with the result of a previous THM investigation on the {sup 7}Li(p,{alpha}){sup 4}He reaction off the neutron in {sup 2}H. A good agreement between data sets shows up throughout the energy range investigated, providing a very important validity test of the pole approximation for the THM. (orig.)

  4. Elastic scattering and fusion cross-sections in 7Li + 27Al reaction

    Indian Academy of Sciences (India)

    D Patel; S Santra; S Mukherjee; B K Nayak; P K Rath; V V Parkar; R K Choudhury

    2013-10-01

    With an aim to understand the effects of breakup and transfer channels on elastic scattering and fusion cross-sections in the 7Li + 27Al reaction, simultaneous measurement of elastic scattering angular distributions and fusion cross-sections have been carried out at various energies (lab = 8.0–16.0 MeV) around the Coulomb barrier. Optical model (OM) analysis of the elastic scattering data does not show any threshold anomaly or breakup threshold anomaly behaviour in the energy dependence of the real and imaginary parts of the OM potential. Fusion cross-section at each bombarding energy is extracted from the measured -particle evaporation energy spectra at backward angles by comparing with the statistical model prediction. Results on fusion cross-sections from the present measurements along with data from the literature have been compared with the coupled-channels predictions. Detailed coupled-channels calculations have been carried out to study the effect of coupling of breakup, inelastic and transfer, channels on elastic scattering and fusion. The effect of 1-stripping transfer coupling was found to be significant compared to that of the projectile breakup couplings in the present system.

  5. The 6Li(e,e'p) and 142,146Nd(e,e'p) reactions

    International Nuclear Information System (INIS)

    In this thesis two special cases of the (e,e'p) reaction are discussed. The first case is a (e,e'p) reaction for which the residual nucleus is unbound. With an unbound residual nucleus in the (e,e'p) reaction the proton-separation energy equals the two-body emission threshold of the target nucleus. Hence such a reaction is very interesting in a study of possible contributions of many-body mechanisms to cross sections obtained in (e,e'p) reactions. These contributions have been studied for the 6Li(e,e'p) reaction. The second case is an investigation of the change in shape of momentum distributions in the (e,e'p) reaction due to deformation effects, by studying proton knockout from 142Nd (spherical in the ground state) and 146N (deformable). The first part of the thesis deals with the 6Li(e,e'p) reaction. First the essential ingredients for the interpretation of the (e,e'p) cross sections are discussed. Three theoretical models, which predict the 6Li(e,e'p) spectral function, are discussed: the harmonic oscillator model shell, a three-body α-n-p cluster model, and another cluster model with different clusterization of the constituents 6Li and 5He. The experimental spectral function is presented and discussed within the theoretical framework. The occurence of reaction mechanisms beyond the quasi-elastic (e,e'p) reaction is investigated. In the second part the 142Ne(e,e'p) an 146Ne(e,e'p) reactions are discussed. The shape of the momentum distribution in deformed nuclei is discussed within the Nilsson model, followed by a summary of the experimental conditions under which the experimental spectral functions of both (e,e'p) reactions have been obtained. The energy-position and momentum distribution of the lowest discrete transitions are compared to the Nilsson-model predictions. (H.W.). 181 p.; 61 figs.; 27 tabs

  6. {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)

  7. Simultaneous description of CF, ICF and TF data of 6,7Li + 209Bi reaction using new ICF mode

    International Nuclear Information System (INIS)

    The systematic behavior of the fusion suppression factors and ICF probability as a function of target mass is not well understood, despite the CF experimental data being available for a number of projectile-target systems. In our recent paper, a new method was proposed to calculate the ICF probability which is based on absorption cross sections obtained from the CDCC calculations. In continuation of this work, we have also carried out similar calculations for 6,7Li + 209Bi where the experimental data of CF and ICF is available. In the recent paper by Marta et al., the semi-classical model calculations were attempted to understand CF and ICF data for 6,7Li + 209Bi, which was not explaining the data quite well. Here, we have demonstrated the use of quantum mechanical treatment for simultaneous explanation of CF, ICF and TF over a large energy range

  8. RBEs of thermal neutron beam and the 10B(n,α)7Li reaction on skin in the hamster

    International Nuclear Information System (INIS)

    The skin relative biologic effectiveness (RBE) of a thermal neutron beam and the 10B(n,α)7Li reaction were determined by using Syrian (Golden) hamsters and compared with the RBE of a 9-MeV electron beam. The boron used in our experiment was 10B-paraboronophenylalanine (10B-BPA). The Kyoto University Research Reactor was used as the source of thermal neutrons. In the skin dose-response curve, thermal neutron beams produced an almost linear relationship between the maximum skin reaction and the absorbed dose. The RBE obtained in this experimental system was about 2.0. The RBEs of the 14N(n,p)14C and the 10B(n,α)7Li reaction were estimated as 3.1 and about 1.6, respectively, with the assumption that each component of radiation was additive

  9. Preliminary study of the 19F(7Li,7Be)19O reaction at 52 MeV with MAGNEX

    CERN Document Server

    Cavallaro, M; Cappuzzello, F; Carbone, D; Foti, A; Orrigo, S E A; Rodrigues, M R D; Schillaci, M; Borello-Lewin, T; Petrascu, H

    2010-01-01

    The 19F(7Li,7Be)19O charge-exchange reaction at 52 MeV incident energy has been performed at INFN-LNS in Catania using the MAGNEX spectrometer. The use of an algebraic ray-reconstruction technique has allowed to extract the 19O excitation energy spectrum and the experimental angular distributions obtained with a single angular setting of the spectrometer.

  10. AB-BNCT beam shaping assembly based on 7Li(p,n)7Be reaction optimization

    International Nuclear Information System (INIS)

    A numerical optimization of a Beam Shaping Assembly (BSA) for Accelerator Based-Boron Neutron Capture Therapy (AB-BNCT) has been performed. The reaction 7Li(p,n)7Be has been considered using a proton beam on a lithium fluoride target. Proton energy and the dimensions of a simple BSA geometry have been varied to obtain a set of different configurations. The optimal configuration of this set is shown.

  11. AB-BNCT beam shaping assembly based on {sup 7}Li(p,n){sup 7}Be reaction optimization

    Energy Technology Data Exchange (ETDEWEB)

    Minsky, D.M., E-mail: minsky@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, UNSAM, M. de Irigoyen 3100 (1650), San Martin (Argentina)] [CONICET, Av. Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina); Kreiner, A.J. [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499 (B1650KNA), San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, UNSAM, M. de Irigoyen 3100 (1650), San Martin (Argentina)] [CONICET, Av. Rivadavia 1917 (C1033AAJ), Buenos Aires (Argentina); Valda, A.A. [Gerencia de Investigacion y Aplicaciones, CNEA, Av. Gral Paz 1499 (B1650KNA), San Martin, Buenos Aires (Argentina)] [Escuela de Ciencia y Tecnologia, UNSAM, M. de Irigoyen 3100 (1650), San Martin (Argentina)

    2011-12-15

    A numerical optimization of a Beam Shaping Assembly (BSA) for Accelerator Based-Boron Neutron Capture Therapy (AB-BNCT) has been performed. The reaction {sup 7}Li(p,n){sup 7}Be has been considered using a proton beam on a lithium fluoride target. Proton energy and the dimensions of a simple BSA geometry have been varied to obtain a set of different configurations. The optimal configuration of this set is shown.

  12. Cation and anion dynamics in the fast-ion conducting rotor phase of 7Li2SO4

    International Nuclear Information System (INIS)

    Complete text of publication follows. At 848 K, lithium sulfate undergoes a first-order phase transition. The high-temperature cubic a phase is a good cation conductor. At the same time, the oxo-anions are rotationally disordered. There has been a long debate about whether and how the rapid anion reorientation might enhance the canon transport through the crystal. We have performed quasielastic neutron scattering experiments on 7Li2SO4 in order to examine both anion and cation dynamics in this material. At Q -1, the quasielastic linewidth varies as DQ2 where D represents the Li tracer diffusion coefficient. At higher Q, we find a wave-like structure with linewidth maxima at 1.4 A-1 and 2.5 A-1 and a minimum at 1.9 A-1. This behavior is typical of coherent diffusion (7Li scatters both coherently and incoherently). We also see, at higher Q, a (coherent) quasielastic contribution from the oxygen nuclei due to the anion reorientation. Oxygen scattering is also found in the sodium cation conducting rotor phase of Na3PO4 where it is the predominant quasielastic component. Since the quasielastic scattering of 7Li2SO4 contains both cation and anion contributions, we perform classical molecular dynamics studies based on pair potentials from the literature. Results of these simulations are compared to the experimental dynamic structure factors. (author)

  13. Improved information on electron screening in 7Li(p,α)α using the Trojan-horse method

    International Nuclear Information System (INIS)

    The available astrophysical S(E) factor data for the reaction 7Li(p,α)α at 10b(E) factor curve for bare nuclides drops below the data, which in turn represent the case of electron-shielded nuclides, i.e. the electron-shielded Ss(E) factor. The comparison between Sb(E) and Ss(E) leads to an electron-screening potential energy Ue=350 eV, which is much higher than the adiabatic limit of 175 eV and not understood at present. The deduced value of Sb(0) is considerably smaller than the previously adopted value of 59 keV b, significantly increasing the calculated abundance of 7Li in big-bang nucleosynthesis. The Trojan-horse method was applied to the reaction 7Li(p,α)α to determine the energy dependence of the Sb(E) factor for 10b(E) curve and suggest that the THM may become a powerful way to obtain improved information on low-energy cross-sections and associated electron-screening effects in a model-independent way. (orig.)

  14. 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.

  15. 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...

  16. Fast neutron response of {sup 6}Li-depleted CLYC detectors up to 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    D' Olympia, N., E-mail: nathan_dolympia@student.uml.edu; Chowdhury, P.; Jackson, E.G.; Lister, C.J.

    2014-11-01

    The response of {sup 6}Li-depleted Cs{sub 2}LiYCl{sub 6} (CLYC) to high-energy neutrons has been investigated using a pair of 1 in.×1 in. crystals. These are the first two detectors of their kind, which will comprise a 16-element array for studies in fast neutron spectroscopy. Their thermal neutron response has been compared with standard CLYC crystals with a {sup 6}Li enrichment of 95%, demonstrating excellent suppression of the overwhelming thermal neutron background. The response to mono-energetic neutrons over a range of 0.5 to 20 MeV was tested. From this, the response function, energy resolution, and pulse-shape discrimination up to 20 MeV were characterized. Detailed Monte Carlo investigations with MCNPX have been used to show that the dominant reaction mechanisms contributing to the observed response are {sup 35}Cl(n,p) and {sup 35}Cl(n,α). Preliminary investigations have also demonstrated the possibility for separating events from these two reactions.

  17. 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.

  18. 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.

  19. River fluxes to the sea from the ocean's 10Be/9Be ratio

    Science.gov (United States)

    von Blanckenburg, F.; Bouchez, J.

    2013-12-01

    The ratio of the meteoric cosmogenic radionuclide 10Be to the stable isotope 9Be is proposed here to be a flux proxy of terrigenous input into the oceans. The ocean's dissolved 10Be/9Be is set by (1) the flux of meteoric 10Be produced in the atmosphere; (2) the denudational flux of the rivers discharging into a given ocean basin; (3) the fraction of 9Be that is released from primary minerals during weathering (meaning the 9Be transported by rivers in either the dissolved form or adsorbed onto sedimentary particles and incorporated into secondary oxides); and (4) the fraction of riverine 10Be and 9Be actually released into seawater. Using published 10Be/9Be data of rivers for which independent denudation rate estimates exist we first find that the global average fraction of 9Be released during weathering into river waters and their particulate load is 20% and does not depend on denudation rate. We then evaluate this quantitative denudation rate proxy by using published dissolved seawater Be isotope data and a compilation of global river loads (15Gt/yr). We find that the measured global average oceanic dissolved 10Be/9Be ratio of about 0.9E-7 is satisfied by the mass balance if only 6.5% of the dissolved and reactive riverine Be is eventually released to the open ocean by boundary exchange. Except for the South Atlantic and the South Pacific, in which the 10Be/9Be ratio is dominated by Be advected through ocean circulation, good agreement results between 10Be/9Be ratios predicted by denudation rates and measured ocean 10Be/9Be ratios when we establish this mass balance for individual ocean basins. As the seawater 10Be/9Be ratio is faithfully recorded in marine chemical precipitates the 10Be/9Be ratio extracted from authigenic sediments can now serve to estimate relative changes in terrigenous input into the oceans back through time on a global and on a basin scale.

  20. River fluxes to the sea from the oceanʼs 10Be/9Be ratio

    Science.gov (United States)

    von Blanckenburg, Friedhelm; Bouchez, Julien

    2014-02-01

    The ratio of the meteoric cosmogenic radionuclide 10Be to the stable isotope 9Be is proposed here to be a flux proxy of terrigenous input into the oceans. The ocean's dissolved 10Be/9Be is set by (1) the flux of meteoric 10Be produced in the atmosphere; (2) the denudational flux of the rivers discharging into a given ocean basin; (3) the fraction of 9Be that is released from primary minerals during weathering (meaning the 9Be transported by rivers in either the dissolved form or adsorbed onto sedimentary particles and incorporated into secondary oxides); and (4) the fraction of riverine 10Be and 9Be actually released into seawater. Using published 10Be/9Be data of rivers for which independent denudation rate estimates exist we first find that the global average fraction of 9Be released during weathering into river waters and their particulate load is 20% and does not depend on denudation rate. We then evaluate this quantitative proxy for terrigenous inputs by using published dissolved seawater Be isotope data and a compilation of global river loads. We find that the measured global average oceanic dissolved 10Be/9Be ratio of about 0.9×10-7 is satisfied by the mass balance if only about 6% of the dissolved and adsorbed riverine Be is eventually released to the open ocean after escaping the coastal zone. When we establish this mass balance for individual ocean basins good agreement results between 10Be/9Be ratios predicted from known river basin denudation rates and measured ocean 10Be/9Be ratios. Only in the South Atlantic and the South Pacific the 10Be/9Be ratio is dominated by advected Be and in these basins the ratio is a proxy for ocean circulation. As the seawater 10Be/9Be ratio is faithfully recorded in marine chemical precipitates the 10Be/9Be ratio extracted from authigenic sediments can now serve to estimate relative changes in terrigenous input into the oceans back through time on a global and on an ocean basin scale.

  1. Photodisintegration of 9Be and the importance of the unbound 1/2+ state

    Directory of Open Access Journals (Sweden)

    Odsuren Myagmarjav

    2016-01-01

    Full Text Available The photodisintegration cross section of the 9Be(1/2+ state is investigated in a framework of the α + α + n three-body model. The 1/2+ state of 9Be locates just above the three-body threshold, and the s-wave neutron property of this state is a long-standing problem. It has been a topic of quite interest in relation to the breakup mechanism of 9Be into the 8Be(0+ + n and (α + α + n channels.

  2. The Benchmark Testing of ~9Be of CENDL-3.0

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The 9Be data of CENDL-3.0 were updated again recently by Prof.Zhang Jing-shang et al. by using anew approach. In order to test the reliability of 9Be data of CENDL-3.0, some benchmarks were used. Inaddition to the values of Keff, the leakage spectrum of Be sphere was calculated. The data processing wascarried out by using the NJOY nuclear data processing code system. The calculations and analyses of

  3. Structure of the mirror nuclei $^{9}$Be and $^{9}$B in a microscopic cluster model

    CERN Document Server

    Arai, K; Suzuki, Y; Varga, K

    1996-01-01

    The structure of the mirror nuclei ^9Be and ^9B is studied in a microscopic \\alpha+ \\alpha+ n and \\alpha+ \\alpha+ p three-cluster model using a fully antisymmetrized 9-nucleon wave function. The two-nucleon interaction includes central and spin-orbit components and the Coulomb potential. The ground state of ^9Be is obtained accurately with the stochastic variational method, while several particle-unbound states of both ^9Be and ^9B are investigated with the complex scaling method.The calculation for ^9Be supports the recent identification for the existence of two broad states around 6.5 MeV, and predicts the \\frac{3}{2}^{-}_2 and \\frac{5}{2}^{-}_2 states at about 4.5 MeV and 8 MeV, respectively. The similarity of the calculated spectra of ^9Be and ^9B enables one to identify unknown spins and parities of the ^9B states. Available data on electromagnetic moments and elastic electron scatterings are reproduced very well. The enhancement of the E1 transition of the first excited state in ^9Be is well accounted f...

  4. 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...

  5. 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.

  6. Investigation of the Triton Emission Asymmetry in the $^{6}$Li(n, alpha)$^{3}$H Reaction with Polarized Thermal Neutrons

    CERN Document Server

    Gledenov, Yu M; Nesvizhevsky, V V; Petukhov, A K; Sedyshev, P V; Soldner, T; Shulgina, E V; Zimmer, O

    2002-01-01

    An experiment was carried out at the high-intensity polarized cold neutron beam of the PF1B instrument of the ILL reactor, Grenoble, France. As a detector, the 48-section ionization chamber with the ^{6}LiF targets was used. An integral (current) method of the event detection with compensation of the reactor power fluctuation was applied. Special measurement technique was used for minimization and estimation of the possible false effect contribution. A value of the P-odd (sigma_{\\bf n}, {\\bf P}_{\\bf n}) correlation has been obtained: alpha_{PN}=-(7.1\\pn 3.9)\\cdot 10^{-8}. At the base of the cluster model, the most accurate at present day estimation of the weak neutral current constant has been given: f_n \\leq 1.2\\cdot 10^{-7}.

  7. 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.

  8. Complete and incomplete fusion cross sections for 6Li+209Bi reaction in multi-body classical molecular dynamical model

    International Nuclear Information System (INIS)

    Using the multi-body Classical Molecular Dynamics simulation of 6Li+209Bi reaction it is shown that: (i) the breakup of a projectile fragment near the barrier leads to substantial increase in the ICF probabilities; (ii) the expected increase in σCF on relaxation of the rigid-body (RB) constraint on the projectile is compensated by reduction in the flux leading to CF, due to ICF events; (iii) the breakup probability increases with ECM and, for given ECM it also increases as b increases and peaks around some b>0, while cross sections σCF and σTF were calculated for b=0 only Therefore, we present the results of σCF (Complete Fusion) and σTF (Total Fusion) calculations which are obtained at critical impact parameter, bcr, where many ICF channels open up and compare with the calculations performed at b=0 only, where only few ICF channels open up

  9. 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.

  10. Study of the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Betsou, C.; Pakou, A.; Aslanoglou, X.; Nicolis, N.G.; Sgouros, O.; Soukeras, V. [The University of Ioannina, Department of Physics and HINP, Ioannina (Greece); Cappuzzello, F. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Acosta, L. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico Distrito Federal (Mexico); INFN, Catania (Italy); Agodi, C.; Carbone, D.; Cavallaro, M.; Di Pietro, A.; Fernandez-Garcia, J.P.; Figuera, P.; Fisichella, M. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN, Catania (Italy); Keeley, N. [National Centre for Nuclear Research, Otwock (Poland); Marquinez-Duran, G.; Martel, I. [Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Mazzocco, M.; Strano, E.; Torresi, D. [Universita di Padova, Departimento di Fisica e Astronomia, Padova (Italy); INFN, Padova (Italy); Pierroutsakou, D. [INFN, Napoli (Italy); Rusek, K. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Stiliaris, E. [University of Athens, Institute of Accelerating Systems and Applications and Department of Physics, Athens (Greece)

    2015-07-15

    Angular distribution measurements were performed for the {sup 6}Li + p → {sup 3}He + {sup 4}He reaction in inverse kinematics at incident energies of 2.7, 3.3, 4.2 and 4.8 MeV/u. The detection of both recoils ({sup 3}He and {sup 4}He) over the laboratory angle range θ{sub lab} = 16 {sup circle} to 34 {sup circle} allowed the determination of the angular distribution over a wide angular range in the center-of-mass frame (θ{sub c.m.} ∝ 40 {sup circle} to 140 {sup circle}). The results clarify inconsistencies between existing data sets and are consistent with compound nucleus model calculations. (orig.)

  11. 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.

  12. Kinematically complete measurements of the break-up of 6Li using the magnetic spectrograph 'Little John'

    International Nuclear Information System (INIS)

    This report describes set-up and application of an extended detection system for the magnetic spectrograph 'Little John'. The set-up is used in experiments of the Coulomb induced break-up of 6Li into α-particles and deuterons at the Karlsruhe Isochronous Cyclotron for the detection of both coincidence fragments. In first measurements the properties of the detection system are explored. It is shown that the extension provides an increased efficiency, simultaneously maintaining the angular resolution. This is achieved by a direct measurement of both particle trajectories and by an off-line subdivision of the solid angle acceptance. The differential cross sections obtained in this way are in a good agreement with known results and are completing the experimental information. (orig.)

  13. Spectral flux of the p-7Li(C Q-M neutron source measured by proton recoil telescope

    Directory of Open Access Journals (Sweden)

    Simakov S.P.

    2010-10-01

    Full Text Available The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p + 7Li(carbon backing reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX. Simulated spectra were tested by absolute measurements using a proton-recoil telescope technique. The recoil-proton spectrometer consisted of a shielded scattering chamber with polyethylene and carbon radiators and the ΔE1-ΔE2-E telescope of silicon-surface detectors located to the neutron beam axis at 45° in the laboratory system. Si-detectors were handled by usual data acquisition system. Dead-time – and pulse-overlap losses of events were determined from the count rate of pulse generator registered during duty cycle of accelerator operation. The proton beam charge and data were taken in the list mode for later replay and analysis. The calculations for 7Li(p,n and 12C(p,n reactions reasonably reproduce CYRIC TOF neutron source spectra. The influence of neutron source set-up (proton beam dimensions, 7Li-foil, carbon stopper, cooling medium, target support/chamber and the geometry-arrangement of irradiated sample on the spectral flux is discussed in details.

  14. Improved information on electron screening in {sup 7}Li(p,{alpha}){alpha} using the Trojan-horse method

    Energy Technology Data Exchange (ETDEWEB)

    Aliotta, M.; Rolfs, C.; Strieder, F. [Inst. fuer Physik mit Ionenstrahlen, Ruhr-Universitaet Bochum (Germany); Spitaleri, C.; Lattuada, M.; Musumarra, A.; Pizzone, R.G. [Dipt. di Metodologie Fisiche e Chimiche per l' Ingegneria, Univ. di Catania (Italy); Tumino, A. [Catania Univ. (Italy). Ist. di Astronomia

    2000-12-01

    The available astrophysical S(E) factor data for the reaction {sup 7}Li(p,{alpha}){alpha} at 10=}100 keV, while at lower energies this calculated S{sub b}(E) factor curve for bare nuclides drops below the data, which in turn represent the case of electron-shielded nuclides, i.e. the electron-shielded S{sub s}(E) factor. The comparison between S{sub b}(E) and S{sub s}(E) leads to an electron-screening potential energy U{sub e}=350 eV, which is much higher than the adiabatic limit of 175 eV and not understood at present. The deduced value of S{sub b}(0) is considerably smaller than the previously adopted value of 59 keV b, significantly increasing the calculated abundance of {sup 7}Li in big-bang nucleosynthesis. The Trojan-horse method was applied to the reaction {sup 7}Li(p,{alpha}){alpha} to determine the energy dependence of the S{sub b}(E) factor for 10

  15. Ab initio no-core properties of 7Li and 7Be with JISP16 and NNLO_opt interactions

    CERN Document Server

    Heng, Taihua; Maris, Pieter

    2016-01-01

    We investigate the properties of 7Li with the JISP16 and chiral NNLO_opt nucleon-nucleon interactions and 7Be with the JISP16 interaction in the ab initio no-core full configuration (NCFC) approach. We calculate selected observables that include energy spectra, point proton root-mean-square radii, electromagnetic moments and transitions. We compare our results with experimental results, where available, as well as with results obtained using nucleon-nucleon plus three-nucleon interactions. We obtain reasonable agreement between theory and experiment for low-lying states that are dominated by p-shell configurations.

  16. Elastic forward analysis using sup 7 Li ions A useful tool for H and light elements determination

    CERN Document Server

    Romero, S; Murillo, G; Berdejo, H M

    2002-01-01

    Films of CN sub x /Si, TiN sub x /AISI 304 and AlO sub x /Si were analyzed with sup 7 Li ions from 4.0 to 4.5 MeV and an experimental arrangement that, through detection of scattered projectiles and recoils by a single detector, allows quantification of H, light elements and heavier ones. A discussion is presented of the capabilities of Rutherford backscattering spectrometry (RBS) and conventional elastic recoil detection analysis (ERDA) compared to elastic forward analysis.

  17. Calculation of Double-Differential Cross Sections of n+7Li Reactions Below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang; HAN Ying-Lu

    2002-01-01

    A new reaction model for light nuclei is proposed to analyze the measured data,especially for analysis of the double-differential cross sections of the outgoing particles.Many channels arc opened in the n + 7Li reaction below En< 20 MeV.The reaction mechanism is very complex,beside the sequential emissions there are also three-body breakup processes.Because of a strong recoil effect of light nucleus reactions,the energy balance is strictly taken into account.The comparisons of the calculated results with the double-differential measurements indicate that the model calculations are successful for the total outgoing neutrons.

  18. R-matrix Analysis for the 8Be System and Features in the p+7Li Reaction Over Resonance Region

    Directory of Open Access Journals (Sweden)

    Kunieda Satoshi

    2016-01-01

    Full Text Available A comprehensive R-matrix analysis is currently underway for the 8Be compound system toward a consistent evaluation of the p+7Li reaction cross-sections over the resonance energy region. In this analysis, the energy eigenvalues are fixed to the level energies given in ENSDF, and we searched for values of the boundary condition parameters as well as the reduced-width amplitudes. It is found that some additional levels are necessary to fit the resonant shape of experimental cross-sections. Besides, the channel radii obtained may be consistent with well-known physical pictures of the atomic nucleus.

  19. R-matrix Analysis for the 8Be System and Features in the p+7Li Reaction Over Resonance Region

    Science.gov (United States)

    Kunieda, Satoshi

    2016-06-01

    A comprehensive R-matrix analysis is currently underway for the 8Be compound system toward a consistent evaluation of the p+7Li reaction cross-sections over the resonance energy region. In this analysis, the energy eigenvalues are fixed to the level energies given in ENSDF, and we searched for values of the boundary condition parameters as well as the reduced-width amplitudes. It is found that some additional levels are necessary to fit the resonant shape of experimental cross-sections. Besides, the channel radii obtained may be consistent with well-known physical pictures of the atomic nucleus.

  20. The non-statistical population of the 11.10 MeV 4+ state in 16O by 12C(6Li, d)

    International Nuclear Information System (INIS)

    When compound nucleus calculations are normalized to the 13.88 MeV 4+12C(6Li,d)16O cross section it is found that the population of the 11.10 MeV 4+ state is underpredicted by a factor of four. These results mean that the anomalous population of the 11.10 MeV 4+ state in 16O by the 12C(6Li,d) reaction is not compound nuclear in origin

  1. Earth surface erosion and weathering from the 10Be (meteoric)/9Be ratio

    Science.gov (United States)

    von Blanckenburg, F.; Bouchez, J.; Wittmann, H.; Dannhaus, N.

    2012-12-01

    A perfect clock of the stability of the Earth surface is one that combines a first isotope the flux of which depends on the release rate during erosion, and a second isotope produced at constant rate. The ratio of the meteoric cosmogenic nuclide 10Be to stable 9Be is such a system. We provide a quantitative framework for its use. In a weathering zone some of the 9Be, present typically in 2.5ppm concentrations in silicate minerals, is released and partitioned between a reactive phase (adsorbed to clay and hydroxide surfaces, given the high partition coefficients at intermediate pH), and into the dissolved phase. The combined mass flux of both phases is defined by the soil formation rate and a mineral dissolution rate - and is hence proportional to the chemical weathering rate and the denudation rate. At the same time, the surface of the weathering zone is continuously exposed to fallout of meteoric 10Be. This 10Be percolates into the weathering zone where it mixes with dissolved 9Be. Both isotopes may exchange with the adsorbed Be, given that equilibration rate of Be is fast relative to soil residence times. Hence a 10Be/9Be(reactive) ratio results in soils from which the total denudation rate can be calculated. A prerequisite is that the flux of meteoric 10Be is known from field experiments or from global production models [1], that the 9Be concentration in bedrock (mostly 2.5ppm) is known [2], and that the reactive Be can be chemically extracted from soil or sediment [3]. In rivers, when reactive Be and dissolved Be equilibrate, a catchment-wide denudation rate can be determined from both sediment and a sample of filtered river water, where the sediment 10Be/9Be ratio is independent of grain size. We have tested this approach in sediment-bound Be and dissolved Be in water of the Amazon and Orinoco basin. The reactive Be was extracted from sediment by combined hydroxylamine and HCl leaches [2]. In the Amazon trunk stream, the Orinoco, Apure, and La Tigra river 10Be

  2. 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

  3. 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.

  4. Reactive and dissolved meteoric 10Be/9Be ratios in the Amazon basin

    Science.gov (United States)

    Wittmann, Hella; Dannhaus, Nadine; von Blanckenburg, Friedhelm; Bouchez, Julien; Suessenberger, Annette; Guyot, Jean-Loup; Maurice, Laurence; Filizola, Naziano; Gaillardet, Jerome; Christl, Marcus

    2014-05-01

    Recently, the ratio of the meteoric cosmogenic nuclide 10Be to stable 9Be has been established as a weathering and erosion proxy where meteoric 10Be/9Be ratios in reactive phases of secondary weathering products leached from detrital Amazonian river sediment were measured[1]. For this dataset, we derived a new 10Be-based mass balance, which compares the fluxes exported during erosion and weathering, Fout, calculated by the sum of [10Be]reac multiplied by gauging-derived sediment discharge and [10Be]dissmultiplied by water discharge, to the meteoric depositional flux Fin. This assessment allows evaluating the weathering state of the Amazon basin. Further, in order to assess equilibration of reactive phases in the water column, we measured (10Be/9Be)reac ratios leached from suspended sediments for two depth profiles of the Amazon (55m depth) and Madeira (12m depth) Rivers, their corresponding surface dissolved 10Be/9Be ratios, as well as dissolved ratios of smaller Amazon tributaries (Beni, Madre de Dios) to compare with published reactive ratios[1]. In these rivers, modest pH and salinity fluctuations help to constrain a 'simple' system that might however still be affected by seasonally changing isotopic compositions between water and suspended sediment[2] and seasonal fluctuations of TSS and TDS[3]. The 10Be-based mass balance shows that in Andean source areas Fout/Fin ≡1, indicating a balance between ingoing and exported flux, whereas in the Shield headwaters, Fout/Fin=0.3, indicating a combination of decay of 10Be during storage and little export of 10Be associated with particulate and dissolved loads. In central Amazonia, the export of 10Be decreases slightly relative to its atmospheric flux as evidenced by Fout/Fin=0.8 for the Amazon and Madeira Rivers. This value is interpreted as being close to steady state, but its modification could be due to additions of Shield-derived sediment to sediment carried in the main river[4]. Regarding the depth profiles, our

  5. Decay analysis of 9Be induced reactions using stable and non deformed targets

    International Nuclear Information System (INIS)

    The pursuit of investigation of decay of compound and non compound nuclear reactions inscribes the cogitation of various processes subsequent to collision between projectile and target nuclei. Hitherto extensive studies have been devoted to understand the structure aspect associated with numerous dominant reaction mechanisms of nuclei. The Decay cross-sections of 217Rn* and 218Fr* formed in reactions 9Be+208Pb and 9Be+209Bi have been studied in framework of DCM at energies varying from Ec.m=(42.0- 67.0) MeV where both the targets have same neutron magicity (N = 126) effect. All calculations have been done for β2-deformed choice of fragmentation and optimum orientation approach

  6. 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.

  7. Investigating sorption on iron-oxyhydroxide soil minerals by solid-state NMR spectroscopy: a 6Li MAS NMR study of adsorption and absorption on goethite

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Paik, Younkee; Julmis, Keinia;

    2005-01-01

    H, the system representing an ideal model system for NMR studies. 6Li resonances with large hyperfine shifts (approximately 145 ppm) were observed above the goethite point of zero charge, providing clear evidence for the presence of Li-O-Fe connectivities, and thus the formation of an inner sphere Li+ complex...

  8. Differences Between a Single- and a Double-Folding Nucleus-^{9}Be Optical Potential

    Science.gov (United States)

    Bonaccorso, A.; Carstoiu, F.; Charity, R. J.; Kumar, R.; Salvioni, G.

    2016-05-01

    We have recently constructed two very successful n-^9Be optical potentials (Bonaccorso and Charity in Phys Rev C89:024619, 2014). One by the Dispersive Optical Model (DOM) method and the other (AB) fully phenomenological. The two potentials have strong surface terms in common for both the real and the imaginary parts. This feature makes them particularly suitable to build a single-folded (light-) nucleus-^9Be optical potential by using ab-initio projectile densities such as those obtained with the VMC method (Wiringa http://www.phy.anl.gov/theory/research/density/). On the other hand, a VMC density together with experimental nucleon-nucleon cross-sections can be used also to obtain a neutron and/or proton-^9Be imaginary folding potential. We will use here an ab-initio VMC density (Wiringa http://www.phy.anl.gov/theory/research/density/) to obtain both a n-^9Be single-folded potential and a nucleus-nucleus double-folded potential. In this work we report on the cases of ^8B, ^8Li and ^8C projectiles. Our approach could be the basis for a systematic study of optical potentials for light exotic nuclei scattering on such light targets. Some of the projectiles studied are cores of other exotic nuclei for which neutron knockout has been used to extract spectroscopic information. For those cases, our study will serve to make a quantitative assessment of the core-target part of the reaction description, in particular its localization.

  9. 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.

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

    International Nuclear Information System (INIS)

    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

  11. 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.

  12. 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.

  13. 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).

  14. Helium Bubbles Cavitation Phenomena in Pb-15.7Li and Potential Impact on Tritium Transport Behaviour in HCLL Breeding Channels

    Energy Technology Data Exchange (ETDEWEB)

    Sedano, L. A.

    2007-09-27

    COMPU task is devoted to develop a Process Flow Diagram (PFD) modelling tool for DEMO tritium cycle for HCLL and HCPB blanket lines for DEMO. At the actual stage of definition of HCLL blanket design line this global objective requires to progress specifically on the physical reliability of tritium transport assessments at blanket design level. A rough reliability assessment with the identify cation of physical phenomena determining permeation rates into the coolant was tentatively advanced in COMPU Task Deliverable 1. In HCLL design, the tritium diffusion in the alloy under the flow conditions and radiation effects in Pb15.7Li can be theoretically justifies ed as the rate limiting processes for tritium transfer into the coolant. This Deliverable 2 focuses on the analysis of a specific radiation effect: the potential role of helium bubbles in Pb15.7Li, the discussion of its implications on tritium assessment for HCLL design and consequently the analysis of its quantitative impact (as cycle input) on HCLL PFD tritium cycle design. Thus, the contents of this report investigate: (1) the rationality of the consideration on HCLL design of helium bubble cavitation phenomena in irradiated Pb15.7Li channels on the base of fundamental analysis (He solution states in Pb15.7Li) from empirical clues provided by Pb15.7Li irradiation tests, (2) a preliminary rough He-bubble cavitation design assessment and bases for a more precise FEM calculation for helium bubble cavitation phenomena in HCLL blanket channels, (3) the analysis of direct experimental data and numerical developments needed for a precise cavitation assessment and (4) a proposal of the lay-out and general specifications of an integral proof-of-principle Cavitation Experiment (Cevitex) of Helium in Pb15.7Li. (Author) 40 refs.

  15. Helium Bubbles Cavitation Phenomena in Pb-15.7Li and Potential Impact on Tritium Transport Behaviour in HCLL Breeding Channels

    International Nuclear Information System (INIS)

    COMPU task is devoted to develop a Process Flow Diagram (PFD) modelling tool for DEMO tritium cycle for HCLL and HCPB blanket lines for DEMO. At the actual stage of definition of HCLL blanket design line this global objective requires to progress specifically on the physical reliability of tritium transport assessments at blanket design level. A rough reliability assessment with the identify cation of physical phenomena determining permeation rates into the coolant was tentatively advanced in COMPU Task Deliverable 1. In HCLL design, the tritium diffusion in the alloy under the flow conditions and radiation effects in Pb15.7Li can be theoretically justifies ed as the rate limiting processes for tritium transfer into the coolant. This Deliverable 2 focuses on the analysis of a specific radiation effect: the potential role of helium bubbles in Pb15.7Li, the discussion of its implications on tritium assessment for HCLL design and consequently the analysis of its quantitative impact (as cycle input) on HCLL PFD tritium cycle design. Thus, the contents of this report investigate: (1) the rationality of the consideration on HCLL design of helium bubble cavitation phenomena in irradiated Pb15.7Li channels on the base of fundamental analysis (He solution states in Pb15.7Li) from empirical clues provided by Pb15.7Li irradiation tests, (2) a preliminary rough He-bubble cavitation design assessment and bases for a more precise FEM calculation for helium bubble cavitation phenomena in HCLL blanket channels, (3) the analysis of direct experimental data and numerical developments needed for a precise cavitation assessment and (4) a proposal of the lay-out and general specifications of an integral proof-of-principle Cavitation Experiment (Cevitex) of Helium in Pb15.7Li. (Author) 40 refs

  16. Analysis of length distribution of short DNA fragments induced by 7Li ions using the random-breakage model

    Institute of Scientific and Technical Information of China (English)

    KONG Fuquan; ZHAO Kui; ZHAN Yong; CAO Tianguang; NI Meinan; SUI Li; CAI Minghui; ZHUO Yizhong

    2005-01-01

    Deoxyribonucleic acid (DNA) is an important bio-macromolecule. DNA double strand breaks (DSBs) are considered to be the most important initial damage responsible for all biological effects induced by ionizing radiation. In this paper the length distribution of DNA fragments induced by 7Li ionizing radiation is fitted with the random breakage model. In this model, the parameter u is the average number of DSBs on every DNA molecule induced by ionizing radiation. The fitting result shows that the random breakage model cannot describe the distribution of DNA fragments in lower doses, while the random breakage model is in better accordance with the experimental data in higher doses. It is shown that the length distribution of DNA fragments has random statistical feature in higher doses. In this situation, the random breakage model looks like a model without any parameter since the u has specific physical meaning and can directly be obtained from experimental data.

  17. New method to evaluate the {sup 7}Li(p, n){sup 7}Be reaction near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, María S., E-mail: herrera@tandar.cnea.gov.ar [Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, Buenos Aires B1650KNA (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917, Ciudad Autónoma de Buenos Aires C1033AAJ (Argentina); Escuela de Ciencia y Tecnología, UNSAM, 25 de Mayo y Francia, Buenos Aires B1650KNA (Argentina); Moreno, Gustavo A. [YPF Tecnología, Baradero S/N, Buenos Aires 1925 (Argentina); Departamento de Física J. J. Giambiagi, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Ciudad Autónoma de Buenos Aires 1428 (Argentina); Kreiner, Andrés J. [Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, Buenos Aires B1650KNA (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917, Ciudad Autónoma de Buenos Aires C1033AAJ (Argentina); Escuela de Ciencia y Tecnología, UNSAM, 25 de Mayo y Francia, Buenos Aires B1650KNA (Argentina)

    2015-04-15

    In this work a complete description of the {sup 7}Li(p, n){sup 7}Be reaction near threshold is given using center-of-mass and relative coordinates. It is shown that this standard approach, not used before in this context, leads to a simple mathematical representation which gives easy access to all relevant quantities in the reaction and allows a precise numerical implementation. It also allows in a simple way to include proton beam-energy spread affects. The method, implemented as a C++ code, was validated both with numerical and experimental data finding a good agreement. This tool is also used here to analyze scattered published measurements such as (p, n) cross sections, differential and total neutron yields for thick targets. Using these data we derive a consistent set of parameters to evaluate neutron production near threshold. Sensitivity of the results to data uncertainty and the possibility of incorporating new measurements are also discussed.

  18. Elastic and inelastic angular distributions of the 7Li+120Sn system for energies near the Coulomb barrier

    Science.gov (United States)

    Zagatto, V. A. B.; Oliveira, J. R. B.; Gasques, L. R.; Alcántara-Núñez, J. A.; Duarte, J. G.; Aguiar, V. P.; Medina, N. H.; Seale, W. A.; Pires, K. C. C.; Freitas, A.; Lubian, J.; Shorto, J. M. B.; Genezini, F. A.; Rossi, E. S., Jr.

    2016-06-01

    The reaction of 7Li+120Sn has been measured at bombarding energies of 21, 24 and 27 MeV. The {2}+\\to {0}+ γ -ray transition in 120Sn was observed and the angular distribution for the 2+ excited state was obtained. Coupled channels and coupled-reaction channels calculations, including the dynamical polarization potential due to the projectile break-up, obtained from continuum discretized coupled channel calculations, were performed. The comparison between the existing experimental elastic angular distribution with the coupled-reaction channels calculations indicates that the 1n stripping transfer is the most intense channel to be coupled and the 2n stripping reaction occurs sequentially rather than directly, however, further data must be analyzed to confirm this indication. The experimental elastic and inelastic scattering data were well described by the calculations, but some discrepancies in these channels may indicate the need for corrections to the nuclear potential and/or the necessity to incorporate further channels.

  19. Breakup of 33.4 MeV/u 17N on a 9Be Target

    Institute of Scientific and Technical Information of China (English)

    HUA Hui; GUO Zhong-Yan; LI Zu-Yu; WANG Hong-Wei; WANG Su-Fang; JIANG Dong-Xing; LI Xiang-Qing; QIAN Tao; WU He-Yu; JIN Gen-Ming; ZHAN Wen-Long; DUAN Li-Min; XIAO Zhi-Guang

    2000-01-01

    Correlation measurements of neutrons and fragments have been performed in a reaction of 33.4 MeV/u 17 N on a 9Be target. Energy spectra of n and nitrogen fragments were obtained at different angles. Based on the nuclear diffraction dissociation model, the measured energy spectra and the neutron angular distributions werereproduced quite well assuming that 1 7 N was composed of 16 N and n or 15 N and 2n interacting with the nonlocal separable potential. The satisfactory agreement between the heoretical calculations and the experimental data shows that the contribution of Coulomb dissociation is negligible in the reaction concerned.

  20. Isovector and isoscalar dipole excitations in $^{9}$Be and $^{10}$Be studied with antisymmetrized molecular dynamics

    CERN Document Server

    Kanada-En'yo, Yoshik

    2015-01-01

    Isovector and isoscalar dipole excitations in $^9$Be and $^{10}$Be are investigated in the framework of antisymmetrized molecular dynamics, in which angular-momentum and parity projections are performed. In the present method, 1p-1h excitations on the ground state and large amplitude $\\alpha$-cluster mode are incorporated. The isovector giant dipole resonance (GDR) in $E>20$ MeV shows the two peak structure which is understood by the dipole excitation in the 2$\\alpha$ core part with the prolate deformation. Because of valence neutron modes against the $2\\alpha$ core, low-energy E1 resonances appear in $E20$ MeV.

  1. 9Be scattering within a four-body continuum-discretized coupled-channels framework

    Directory of Open Access Journals (Sweden)

    Casal J.

    2016-01-01

    Full Text Available The scattering of 9Be on 208Pb is addressed within a four-body Continuum-Discretized Coupled-Channels (CDCC framework, considering a three-body α + α + n projectile plus a structureless target. The projectile states are generated using the analytical Transformed Harmonic Oscillator (THO basis in hyperspherical coordinates. Both the elastic and breakup channels are described on the same footing. We find a good agreement between our calculations and the experimental data at beam energies around and below the Coulomb barrier.

  2. No-capture breakup and incomplete fusion reactions induced by stable weakly bound nucleus 9Be

    Science.gov (United States)

    Seyyedi, S. A.

    2016-06-01

    The reactions including the stable weakly bound nucleus 9Be have been studied using the classical trajectory model accompanied with the experimental breakup function and the Aage-Winther interaction potential (AW95). In these calculations, the no-capture breakup and the incomplete fusion cross-sections as well as their competition at around the Coulomb barrier have been investigated. Our calculations showed that at a given far-Coulomb-barrier energy the incomplete fusion reaction in different distributions of angular momentum and energies can dominate the no-capture breakup reaction. This dominating process is reversed at the near-barrier energies.

  3. Spectroscopy of high lying resonances in 9Be produced with radioactive 8Li beams

    Directory of Open Access Journals (Sweden)

    Lépine-Szily A.

    2014-04-01

    Full Text Available We present the results of the 8Li(p,α5He and 8Li(p,p8Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil system. The experiment was realized in inverse kinematics using a thick [CH2]n polyethylene target and an incident 8Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between Ecm = 0.2 − 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the 8Li(p,α5He reaction, populating resonances between 16.888 and 19.0 MeV in 9Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in 9Be. The measurement of the resonant elastic scattering 8Li(p,p8Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented.

  4. A High-Precision Determination of the Astrophysical Rate for Production of ^9Be

    Science.gov (United States)

    Arnold, C. W.; Clegg, T. B.; Karwowski, H. J.; Rich, G. C.; Tompkins, J. R.; Howell, C. R.

    2010-11-01

    New cross section measurements of the astrophysically important ^9Be(γ,n) reaction have been made from 1.5 to 5.18 MeV. The measurements were made using the nearly monoenergetic circularly polarized γ-ray beam at Triangle Universities Nuclear Laboratory's High Intensity γ-ray Source. Measurements over narrow resonances employed beams with energy spread dE/E <= 1%. The energy-dependent absolute efficiency of the neutron counter used in this work was measured to ± 3% accuracy. New resonance parameters for the 4 lowest lying states in ^9Be were determined. A new reaction rate for α+ α+ n has been determined to better than ± 5%. The present rate is ˜ 25% larger than two widely accepted rates [1-2] in the temperature range important for r-process nucleosynthesis. The implications of this new rate on r-process and nuclear abundance predictions will be discussed.[4pt] [1] C. Angulo et al. Nuc. Phys. A 656 (1999) 3-183. [0pt] [2] K. Sumiyoshi et al. Nuc. Phys A 709 (2002) 467-486.

  5. Imaginary part of the 9C-9Be single-folded optical potential

    Science.gov (United States)

    Bonaccorso, A.; Carstoiu, F.; Charity, R. J.

    2016-09-01

    In a recent publication we have argued that using two very successful n -9Be optical potentials [A. Bonaccorso and R. J. Charity, Phys. Rev. C 89, 024619 (2014), 10.1103/PhysRevC.89.024619] and microscopic projectile densities, it is possible to build a single-folded (light-) nucleus-9Be imaginary optical potential which is more accurate than a double-folded optical potential. By comparing to experimental reaction cross sections, we showed for 8B,8Li, and 8C projectiles, that a very good agreement between theory and data could be obtained with such a "bare" potential, at all but the lowest energies where a small semimicroscopic surface term was added to the single-folded potential to take into account projectile breakup. In this paper we extend this study to the case of 9C projectiles and assess the sensitivity to the projectile density used. We then obtained the modulus of the nucleus-nucleus S matrix and parametrize it in terms of a strong-absorption radius Rs and finally extracted the phenomenological energy dependence of this radius. This approach could be the basis for a systematic study of optical potentials for light exotic nuclei scattering on light targets and/or parametrizations of the S matrix. Furthermore our study will serve to make a quantitative assessment of the description of the core-target part of knockout reactions, in particular their localization in terms of impact parameters.

  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. Examination of the Coulomb-nuclear interference in inelastic scattering of {sup 6}Li in {sup 76}Ge; Exame da interferencia Coulombiana-Nuclear no espalhamento inelastico de {sup 6}Li em {sup 76}Ge

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinxin

    2015-07-01

    The inelastic scattering of 28,0 MeV {sup 6}Li on {sup 76}Ge in the excitation of the 2{sup +}{sub 1} state, has been studied with the Coulomb-Nuclear Interference (CNI) analysis. The data were measured at the Pelletron-Enge-Spectrograph facility at LAFN-IFUSP. A solid-state position sensitive silicon detector (PSD) (500μm thickness and 47 × 8 mm{sup 2} area) was used to measure the data at the spectrometer focal plane. Digital pulse processing (DPP) was implemented in the acquisition system. Twenty-six spectra were measured at carefully chosen scattering angles in the range of 10 deg ≤ θ{sub Lab} ≤ 55 deg to obtain an angular distribution. The analysis was performed with the Distorted Wave Born Approximation (DWBA) and applied for the nuclear transition potential, the Deformed Optical Potential Model (DOMP), under well-established global optical parameters. The fit of the predicted cross sections to the experimental data through χ{sup 2} minimization, using the iterative method of Gauss, allowed for the extraction of the correlated parameters, δ{sup N}{sub 2}, the mass deformation length, and C{sub 2} = Ν{sup C}{sub 2}/δ{sup N}{sub 2}, the ratio between charge and mass deformation lengths. The correlated parameters obtained in the present work were C{sub 2} = 1,101 (20) and δ{sup N}{sub 2} = 1,08(21)fm. Statistical tests, through a Monte Carlo simulation of 5000 new data sets, validated the method employed in the correlated parameters fit. The methodology applied for the CNI analysis allowed the extraction of ratio B(EL)/B(ISL), which is proportional to the square of C{sub 2}, with a good precision due to the scale uncertainties cancellation of the absolute cross sections. The values of B(IS2) and of the ratios B(E2)/B(IS2) obtained in the present work have not been reported before and allow the study of the evolution of the collectivity throughout the even-A germanium chain together with former results obtained for the {sup 70},{sup 72},{sup 74}Ge

  8. Study of the 3He(α,γ)7Be and 3H(α,γ)7Li reactions at astrophysical energies

    Science.gov (United States)

    Sadeghi, H.; Ghasemi, R.

    2014-06-01

    We have studied the important astrophysical 3He(α,γ)7Be and 3H(α,γ)7Li reactions in the framework of a potential model. 3He(α,γ)7Be and 3H(α,γ)7Li processes are key reactions in both bigbang nucleosynthesis and the p-p chain of hydrogen-burning in stars. The stellar 3He(α,γ)7Be and 3H(α,γ)7Li reactions were analyzed at low energies on the basis of a direct radiative capture mechanism. The astrophysical S-factors near zero energy were calculated without using the effective expansion of the S-factor or the asymptotic wave functions. In this paper, 3He(α,γ)7Be and 3H(α,γ)7Li radiative capture reactions at very low energies are taken as a case study. Using the M3Y potential, we have calculated the astrophysical S-factors for the E1 transition. In comparison with other theoretical methods and available experimental data, excellent agreement is achieved for the astrophysical S-factors of these processes.

  9. Breakup of 42 MeV 7Li projectiles in the fields of 12C and 197Au nuclei

    Indian Academy of Sciences (India)

    Dhruba Gupta; C Samanta; R Kanungo; P Basu; Subinit Roy; S Kailas; A Chatterjee; B J Roy; K Mahata; A Samant; A Shrivastava

    2001-07-01

    Inclusive cross sections of particles and tritons from the breakup of 42 MeV 7Li by 12C and 197Au targets are presented and analysed in the framework of the Serber model. Spectral distortions due to the targets and relevant reaction mechanisms are discussed.

  10. Specific heat measurements of TiB{sub 2} and {sup 6}LiF from 0.5 to 30 K

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Brian E. [Department of Chemistry and Biochemistry, Brigham Young University, C100 Benson Science Building, P.O. Box 25700, Provo, UT 84602 (United States); Donaldson, Marcus H. [Department of Chemistry and Biochemistry, Brigham Young University, C100 Benson Science Building, P.O. Box 25700, Provo, UT 84602 (United States); Woodfield, Brian F. [Department of Chemistry and Biochemistry, Brigham Young University, C100 Benson Science Building, P.O. Box 25700, Provo, UT 84602 (United States)]. E-mail: brian_woodfield@byu.edu; Burger, Arnold [Department of Physics, Fisk University, Nashville, TN 37208 (United States); Roy, Utupal N. [Department of Physics, Fisk University, Nashville, TN 37208 (United States); Lamberti, Vincent [Y-12 National Security Complex, P.O. Box 2009, Oak Ridge, TN 37831 (United States); Bell, Zane W. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2005-12-01

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

  11. Pairing-gap, pseudogap, and no-gap phases in the radio-frequency spectra of a trapped unitary {sup 6}Li gas

    Energy Technology Data Exchange (ETDEWEB)

    Pieri, P.; Perali, A.; Strinati, G. C. [Dipartimento di Fisica, Universita di Camerino, I-62032 Camerino (Italy); Riedl, S.; Altmeyer, A.; Grimm, R. [Institut fuer Experimentalphysik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, A-6020 Innsbruck (Austria); Wright, M. J.; Kohstall, C.; Sanchez Guajardo, E. R.; Hecker Denschlag, J. [Institut fuer Experimentalphysik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, A-6020 Innsbruck (Austria)

    2011-07-15

    Radio frequency spectra of a trapped unitary {sup 6}Li gas are reported and analyzed in terms of a theoretical approach that includes both final-state and trap effects. The different strength of the final-state interaction across the trap is crucial for evidencing two main peaks associated with two distinct phases residing in different trap regions. These are the pairing-gap and pseudo-gap phases below the critical temperature T{sub c}, which evolve into the pseudo-gap and no-gap phases above T{sub c}. In this way, a long standing puzzle about the interpretation of rf spectra for {sup 6}Li in a trap is solved.

  12. Viabilidad técnica para la explotación y separación isotópica de Li y prospectiva en el mercado de baterías de ION-7Li y de 6Li como material base de diseño en reactores de fusión nuclear

    OpenAIRE

    Herranz García, José Luis

    2013-01-01

    En claro alineamiento con estrategias de sostenibilidad en el uso de recursos naturales en un escenario constante de aumento de la demanda energética mundial, el desarrollo de la tecnología energética en la Historia de la Especie Humana muestra un vector de evolución permanente desde su origen en el sentido del desarrollo y uso de nuevas fuentes energéticas con la explotación de recursos naturales de manera más eficiente: soluciones energéticas con aumento de la densidad energética (exoenergí...

  13. Experimental Study of the {sup 6}Li(d,{alpha}){sup 4}He Reaction and its Astrophysical Implications via the Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Pizzone, R.G.; Aliotta, M.; Blagus, S.; Cherubini, S.; Figuera, P.; Lattuada, M; Milin, M.; Miljanic, D.; Pellegriti, M.G.; Rendic, D.; Romano, S.; Soic, N.; Spitaleri, C.; Zadro, M.; Zappala, R.A.

    2000-12-31

    The {sup 6}Li(d, {alpha}){sup 4}He reaction, whose astrophysical importance is connected to the primordial nucleosynthesis in the framework of the Inhomogeneous Big Bang, has been studied by using the Trojan Horse Method (THM). We derive and discuss the cross section and the astrophysical S(E)-factor for E{sub cm}=0.025-0.7 MeV. Results are compared with data from a direct measurement.

  14. Energy dependence of the 6Li(π+,3He)3He reaction at 60, 75 and 90 MeV

    International Nuclear Information System (INIS)

    Differential cross sections for the pionic fission reaction 6Li(π+,3He)3He at T sub(π) = 60, 75 and 90 MeV have been measured for theta sub(c.m.) = 4l degrees. The energy dependence of the differential cross section is found to follow an exponential decrease with increasing incident pion energy and is compared with existing theoretical predictions

  15. 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.

  16. S-factor measurement of the 2H(α,γ)6Li reaction at energies relevant for Big-Bang nucleosynthesis

    International Nuclear Information System (INIS)

    For about 20 years now, observations of 6Li in several old metal-poor stars inside the halo of our galaxy have been reported, which are largely independent of the stars' metallicity, and which point to a possible primordial origin. The observations exceed the predictions of the Standard Big-Bang Nucleosynthesis model by a factor of 500. In the relevant energy range, no directly measured S-factors were available yet for the main production reaction 2H(α,γ)6Li, while different theoretical estimations have an uncertainty of up to two orders of magnitude. The very small cross section in the picobarn range has been measured with a deuterium gas target at the LUNA accelerator (Laboratory for Underground Nuclear Astrophysics), located deep underground inside Laboratori Nazionali del Gran Sasso in Italy. A beam-induced, neutron-caused background in the γ-detector occurred which had to be analyzed carefully and subtracted in an appropriate way, to finally infer the weak signal of the reaction. For this purpose, a method to parameterize the Compton background has been developed. The results are a contribution to the discussion about the accuracy of the recent 6Li observations, and to the question if it is necessary to include new physics into the Standard Big-Bang Nucleosynthesis model.

  17. Large basis ab initio shell model investigation of 9-Be and 11-Be

    CERN Document Server

    Forssén, C; Ormand, W E; Caurier, E

    2004-01-01

    We are presenting the first ab initio structure investigation of the loosely bound 11-Be nucleus, together with a study of the lighter isotope 9-Be. The nuclear structure of these isotopes is particularly interesting due to the appearance of a parity-inverted ground state in 11-Be. Our study is performed in the framework of the ab initio no-core shell model. Results obtained using four different, high-precision two-nucleon interactions, in model spaces up to 9\\hbar\\Omega, are shown. For both nuclei, and all potentials, we reach convergence in the level ordering of positive- and negative-parity spectra separately. Concerning their relative position, the positive-parity states are always too high in excitation energy, but a fast drop with respect to the negative-parity spectrum is observed when the model space is increased. This behavior is most dramatic for 11-Be. In the largest model space we were able to reach, the 1/2+ level has dropped down to become either the first or the second excited state, depending ...

  18. Statistical theory of light nucleus reaction and application to $^9$Be(p, xn) reaction

    CERN Document Server

    Sun, Xiaojun

    2016-01-01

    A statistical theory of light nucleus reaction (STLN) is proposed to describe both neutron and light charged particle induced nuclear reactions with 1p-shell light nuclei involved. The dynamic of STLN is described by the unified Hauser-Feshbach and exciton model, of which the angular momentum and parity conservations are considered in equilibrium and pre-equilibrium processes. The Coulomb barriers of the incident and outgoing charged particles, which seriously influence the open reaction channels, could be reasonably considered in the incident channel and the different outgoing channels. In kinematics, the recoiling effects in various emission processes are taken strictly into account. Taking $^9$Be(p, xn) reaction as an example, we calculate the double-differential cross sections of outgoing neutrons and charged particles using PUNF code in the frame of STLN. The calculated results agree very well with the existing experimental neutron double-differential cross sections at $E_p=18$ MeV, and indicate that PUN...

  19. Exploring the N{alpha}+3n light nuclei via the ({sup 7}Li,{sup 7}Be) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nociforo, C.; Cappuzzello, F.; Orrigo, S.E.A.; Winfield, J.S. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Cunsolo, A.; Cavallaro, M. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); Foti, A. [Universita di Catania, Dipartimento di Fisica e Astronomia, Catania (Italy); INFN-Sezione di Catania, Catania (Italy); Fortier, S.; Beaumel, D. [Institut de Physique Nucleaire, Orsay Cedex (France); Lenske, H. [Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)

    2006-03-15

    Experimental signatures of the dynamical correlations of a core with a single-particle neutron have been found in light neutron-rich nuclei investigated via the ({sup 7}Li,{sup 7}Be) charge-exchange reactions at around 8 MeV/u. Of particular astrophysical relevance are low-lying narrow resonances ({gamma}{proportional_to}200 keV FWHM) BSEC (Bound States Embedded in the Continuum). Because of their long lifetime BSEC states are likely to effect the capture rates in any scenario for nucleosynthesis in neutron-rich environment. They have been observed in the continuum of {sup 11}Be and {sup 15}C nuclei. A microscopic nuclear structure model based on QRPA theory, which takes into account Dynamical Core Polarisation (DCP) correlations, gives a suitable description of these resonances as well as single-particle states of the studied systems. In this context, high-energy narrow structures populated in nuclei having an integer number of {alpha}-particles plus three neutrons are good BSEC candidates and can be systematically investigated. (orig.)

  20. 7Li nuclear magnetic resonance studies of dynamics in a ternary gel polymer electrolyte based on polymeric ionic liquids

    International Nuclear Information System (INIS)

    The influence of the polymeric ionic liquid (PIL) Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl) imide) (PDADMATFSI) on the lithium dynamics was investigated in a ternary gel polymer electrolyte consisting of PDADMATFSI as stabilizing polymer, ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, P14TFSI) and lithium salt (lithium bis(trifluoromethylsulfonyl) imide, LiTFSI). The diffusion coefficient of the lithium ions is investigated by pulsed-field-gradient NMR, the conductivity of the electrolyte is determined by impedance spectroscopy. The local lithium dynamics is characterized by 7Li spin lattice relaxation rates (R1). The relaxation rates are well described by Blombergen-Purcell-Pound (BPP) theory at all polymer concentrations (up to 45 mol%), implying that the Li dynamics is governed by one single motional mode. Interestingly, activation energies for this motion decrease from 20 kJ/mol to 15 kJ/mol with increasing polymer content and are independent on the salt content. We thus conclude that the polymer is interacting with the anion coordination shell, which is accompanied by a very beneficial effect on the local lithium dynamics, as the polymer PDADMATFSI reduces the Li-TFSI interactions. This result is promising for further investigations for potential use of PDADMATFSI-containing gels as electrolytes in energy storage devices

  1. Dynamical 3-Space Predicts Hotter Early Universe: Resolves CMB-BBN 7-Li and 4-He Abundance Anomalies

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2010-01-01

    Full Text Available The observed abundances of 7 Li and 4 He are significantly inconsistent with the pre- dictions from Big Bang Nucleosynthesis (BBN when using the CDM cosmolog- ical model together with the value for B h 2 = 0 : 0224 0 : 0009 from WMAP CMB fluctuations, with the value from BBN required to fit observed abundances being 0 : 009 < B h 2 < 0 : 013. The dynamical 3-space theory is shown to predict a 20% hot- ter universe in the radiation-dominated epoch, which then results in a remarkable parameter-free agreement between the BBN and the WMAP value for B h 2 . The dy- namical 3-space also gives a parameter-free fit to the supernova redshift data, and pre- dicts that the flawed CDM model would require = 0 : 73 and M = 0 : 27 to fit the 3-space dynamics Hubble expansion, and independently of the supernova data. These results amount to the discovery of new physics for the early universe that is matched by numerous other successful observational and experimental tests.

  2. Dynamical 3-Space Predicts Hotter Early Universe: Resolves CMB-BBN 7-Li and 4-He Abundance Anomalies

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2010-01-01

    Full Text Available The observed abundances of 7-Li and 4-He are significantly inconsistent with the predictions from Big Bang Nucleosynthesis (BBN when using the $Lambda$CDM cosmological model together with the value for $Omega_B h^2 = 0.0224pm0.0009$ from WMAP CMB fluctuations, with the value from BBN required to fit observed abundances being $0.009 < Omega_B h^2 < 0.013$. The dynamical 3-space theory is shown to predict a 20% hotter universe in the radiation-dominated epoch, which then results in a remarkable parameter-free agreement between the BBN and the WMAP value for $Omega_B h^2$. The dynamical 3-space also gives a parameter-free fit to the supernova redshift data, and predicts that the flawed $Lambda$CDM model would require $Omega_Lambda = 0.73$ and $Omega_M = 0.27$ to fit the 3-space dynamics Hubble expansion, and independently of the supernova data. These results amount to the discovery of new physics for the early universe that is matched by numerous other successful observational and experimental tests.

  3. Large basis ab initio shell model investigation of 9Be and 11Be

    Energy Technology Data Exchange (ETDEWEB)

    Forssen, C; Navratil, P; Ormand, W E; Caurier, E

    2004-11-19

    We are presenting the first ab initio structure investigation of the loosely bound {sup 11}Be nucleus, together with a study of the lighter isotope {sup 9}Be. The nuclear structure of these isotopes is particularly interesting due to the appearance of a parity-inverted ground state in {sup 11}Be. Our study is performed in the framework of the ab initio no-core shell model. Results obtained using four different, high-precision two-nucleon interactions, in model spaces up to 9{h_bar}{Omega}, are shown. For both nuclei, and all potentials, we reach convergence in the level ordering of positive- and negative-parity spectra separately. Concerning their relative position, the positive-parity states are always too high in excitation energy, but a fast drop with respect to the negative-parity spectrum is observed when the model space is increased. This behavior is most dramatic for {sup 11}Be. In the largest model space we were able to reach, the 1/2{sup +} level has dropped down to become either the first or the second excited state, depending on which interaction we use. We also observe a contrasting behavior in the convergence patterns for different two-nucleon potentials, and argue that a three-nucleon interaction is needed to explain the parity inversion. Furthermore, large-basis calculations of {sup 13}C and {sup 11}B are performed. This allows us to study the systematics of the position of the first unnatural-parity state in the N = 7 isotone and the A = 11 isobar. The {sup 11}B run in the 9{h_bar}{Omega} model space involves a matrix with dimension exceeding 1.1 x 10{sup 9}, and is our largest calculation so far. We present results on binding energies, excitation spectra, level configurations, radii, electromagnetic observables, and {sup 10}Be + n overlap functions.

  4. 通过在线7Li-NMR谱对负离子聚合见解的进一步验证%FURTHER CONFIRMATION OF THE ANIONIC POLYMERIZATION INSIGHT THROUGH in situ 7Li-NMR SPECTRUM

    Institute of Scientific and Technical Information of China (English)

    胡迪航; 吴尚翰; 李天一; 郑安呐; 管涌

    2013-01-01

    通过对正丁基锂(n-BuLi)/四氢呋喃(THF)引发α-甲基苯乙烯(mSt)负离子本体聚合,验证了n-BuLi缔合体可以引发聚合,形成超分子团聚体,然后在进一步聚合过程中超分子解离.证实了先前提出的负离子聚合的引发机理.通过7 Li-NMR对聚合过程的在线检测,进一步证实了mSt在氘代苯为溶剂,THF为调节剂下的负离子聚合以及异戊二烯在非极性条件下的溶液聚合都存在引发剂多元缔合体向二元缔合体转变.研究还发现,少量THF可能使n-BuLi的六元缔合结构2~3个进一步串联起来,但先于六元缔合结构解离.此外,THF与n-BuLi作用,随着n-BuLi/THF的摩尔比从1∶1到1∶5的变化,可以使n-BuLi的巨大缔合体解离并向六元缔合体转变.

  5. Charge transfer in Li/CFx-silver vanadium oxide hybrid cathode batteries revealed by solid state 7Li and 19F nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Sideris, Paul J.; Yew, Rowena; Nieves, Ian; Chen, Kaimin; Jain, Gaurav; Schmidt, Craig L.; Greenbaum, Steve G.

    2014-05-01

    Solid state 7Li and 19F magic angle spinning nuclear magnetic resonance (MAS NMR) experiments are conducted on several cathodes containing CFx-Silver vanadium oxide (CFx-Ag2V4O11) hybrid cathodes discharged to 50% depth of discharge (DoD) and stored at their open-circuit voltage for a period of one and three months. Three carbonaceous sources for the CFx phase are investigated: petroleum coke-based, fibrous, and mixed fibrous. For each hybrid cathode, a measurable increase in the relative amount of lithium fluoride is observed after a three month resting period in both the 7Li and 19F NMR spectra. These changes are attributed to lithium ion migration from the silver vanadium oxide to the CFx phase during the resting period, and help clarify the mechanism behind high power handling capability of this cathode.

  6. Neutron characterization study for D–T, p-{sup 7}Li neutron sources with new BCA based direct collision coupling method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guan-bo, E-mail: wgb04dep@hotmail.com [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Yang, Xin [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Qian, Da-zhi; Li, Run-dong; Tang, Bin [Insititute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China)

    2014-09-01

    The T(D,n){sup 4}He and {sup 7}Li(p,n){sup 7}Be neutron sources have been used for decades in nuclear physics research, stellar nucleosynthesis research and neutron therapy research. In this work, the neutron characterization including neutron yield, spectra, and angular distribution for D–T and p-{sup 7}Li sources have been studied with our new binary collision approximation (BCA) based direct collision coupling method. Distinguished from the traditional path integration method for getting the neutron weight, the new model establishes a relationship between the scattering cross section and the impact parameter, which allows the secondary neutron generation carrying out jointly with ions BCA tracking. The experimental measurements of neutron characterizations have been employed for these two reactions, and the new algorithm is validated.

  7. Accurate Analytic Potential Energy Function and Spectroscopic Study for G1 ∏g State of Dimer 7Li2

    Institute of Scientific and Technical Information of China (English)

    SHI De-Heng; MA Heng; SUN Jin-Feng; ZHU Zun-Lue

    2007-01-01

    The reasonable dissociation limit for the G1∏g state of dimer 7Li2 is determined. The equilibrium internuclear distance, dissociation energy, harmonic frequency, vibrational zero energy, and adiabatic excitation energy are calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space in Gaussian03 program package at such numerous basis sets as 6-311++G, 6-311++G(2df, 2pd), 6-311++G(2df, p), cc-PVTZ, 6-311++G(3df, 3pd), CEP-121G, 6-311++G(2df, pd), 6-311++G(d,p),6-311G(3df,3pd), D95(3df,3pd), 6-311++G(3df, 2p),6-311++G(2df), 6-311++G(df, pd) D95V++, and DGDZVP. The complete potential energy curves are obtained at these sets over a wide internuclear distance range and have least squares fitted to Murrell-Sorbie function. The conclusion shows that the basis set 6-311++G(2df, p) is a most suitable one for the G1∏g state. At this basis set, the calculated spectroscopic constants Te, De, Eo, Re, ωe, ωeXe, αe, and Be are of 3.9523 eV, 0.813 06 eV, 113.56 cm-1, 0.320 15 nm,227.96 cm-1, 1.6928 cm-1, 0.004 436 cm-1, and 0.4689 cm-1, respectively, which are in good agreement with measurements whenever available. The total 50 vibrational levels and corresponding inertial rotation constants are for the first time calculated and compared with available RKR data. And good agreement with measurements is obtained.

  8. Au, Bi, Co and Nb cross-section measured by quasimonoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV

    Science.gov (United States)

    Majerle, M.; Bém, P.; Novák, J.; Šimečková, E.; Štefánik, M.

    2016-09-01

    Au, Bi, Co and Nb samples were irradiated several times with quasi-monoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV. The activities of the samples were measured with the HPGe detector and the reaction rates were calculated. The cross-sections were extracted using the SAND-II method with the reference cross-sections from the EAF-2010 database. The uncertainties of the final results are discussed.

  9. Optical Potential Parameters for Halo Nucleus System 6He+12C from Transfer Reaction11B (7Li, 6He) 12C

    Institute of Scientific and Technical Information of China (English)

    WU Zhen-Dong; XU Xin-Xing; BAI Chun-Lin; YU Ning; JIA Fei; LIN Cheng-Jian; ZHANG Huan-Qiao; LIU Zu-Hua; YANG Feng; AN Guang-Peng; ZHANG Chun-Lei; ZHANG Gao-Long; JIA Hui-Ming

    2009-01-01

    The optical potential parameters for the halo nucleus system 6He+12 C are extracted from fits to the measured angular distributions of 11B(7 Li, 6He)12C reaction at energies of 18.3 and 28.3 MeV with distorted-wave Born approximation analysis. The characters of the obtained optical potential parameters are basically consistent with the results extracted from the fits to the elastic-scattering angular distributions in the literature.

  10. Synthesis and optical characterization of LiKB4O7, Li2B6O10, and LiCsB6O10 glasses

    Energy Technology Data Exchange (ETDEWEB)

    Adamiv, V.; Teslyuk, I.; Dyachok, Ya.; Romanyuk, G.; Krupych, O.; Mys, O.; Martynyuk-Lototska, I.; Burak, Ya.; Vlokh, R.

    2010-10-01

    In the current work we report on the synthesis of LiKB4O7, Li2B6O10, and LiCsB6O10 borate glasses. The results for their piezo-optic, acousto-optic, acoustic, elastic, refractive, optical transmission, and optical resistance properties are also presented. It is shown that some of these glasses represent efficient acousto-optic materials that are transparent down to the vacuum ultraviolet range and highly resistant to laser radiation.

  11. Synthesis and optical characterization of LiKB4O7, Li2B6O10, and LiCsB6O10 glasses.

    Science.gov (United States)

    Adamiv, V; Teslyuk, I; Dyachok, Ya; Romanyuk, G; Krupych, O; Mys, O; Martynyuk-Lototska, I; Burak, Ya; Vlokh, R

    2010-10-01

    In the current work we report on the synthesis of LiKB(4)O(7), Li(2)B(6)O(10), and LiCsB(6)O(10) borate glasses. The results for their piezo-optic, acousto-optic, acoustic, elastic, refractive, optical transmission, and optical resistance properties are also presented. It is shown that some of these glasses represent efficient acousto-optic materials that are transparent down to the vacuum ultraviolet range and highly resistant to laser radiation.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. A microscopic three-cluster model with nuclear polarization applied to the resonances of 7Be and the reaction 6Li(p,3He)4He

    CERN Document Server

    Vasilevsky, V S; Broeckhove, J; Kovalenko, T P

    2008-01-01

    A microscopic model for three-cluster configurations in light nuclei is presented. It uses an expansion in terms of Faddeev components for which the dynamic eqations are derived. The model is designed to investigate binary channel processes in a compound system. Gaussian and oscillator bases are used to expand the wave function and to represent appropriate boundary conditions. We study the effect of cluster polarization on ground and resonance states of 7Be, and on the astrophysical S-factor of the reaction 6Li(p,3He)4He.

  17. Test of special relativity theory by means of laser spectroscopy on relativistic {sup 7}Li{sup +} ions in the ESR; Test der Speziellen Relativitaetstheorie mittels Laserspektroskopie an relativistischen {sup 7}Li{sup +}-Ionen am ESR

    Energy Technology Data Exchange (ETDEWEB)

    Botermann, Benjamin

    2012-10-31

    The invariance under Lorentz transformation of the laws of physics is a fundamental postulate of modern physics and all theories of the fundamental interactions have been stated in a covariant form. Although the theory of Special Relativity (SR) has been tested and confirmed with high accuracy in a large number of experiments, improved tests are of fundamental interest due to the far-reaching relevance of this postulate. Additionally modern attempts of a unified description of the four fundamental interactions point to possible violations of Lorentz invariance. In this context experiments of the Ives-Stilwell type for a test of time dilation play an important role. High resolution laser spectroscopy is applied on relativistic particle beams to investigate the validity of the relativistic Doppler formula - and therefore of the time dilation factor γ. In the course of this thesis an Ives-Stilwell experiment was performed with {sup 7}Li{sup +} ions at a velocity of 34 % of the speed of light, which were stored at the experimental storage ring (ESR) of the GSI Helmholtzzentrum fuer Schwerionenforschung. The techniques of Λ- as well as saturation spectroscopy were employed on the 1s2s{sup 3}S{sub 1}→1s2p{sup 3}P{sub 2} transition. By a computer based analysis of the fluorescence detection system and utilization of appropriate edge filters the signal to noise ratio was decisively improved and the application of an additional pump laser allowed for the observation of a saturation signal for the first time. The frequency stability of both laser systems was specified by means of a frequency comb to obtain the highest possible accuracy. The data from the beam times were analyzed in the frameworks of the Robertson-Mansouri-Sexl test theory (RMS) and the Standard Model Extension (SME) and the corresponding upper limits of the relevant test parameters of the assigned theories were calculated. The upper limit of the parameter α was improved by a factor of 4 compared to

  18. Evidence for a dynamically refracted primary bow in weakly bound 9Be rainbow scattering from 16O

    Science.gov (United States)

    Ohkubo, S.; Hirabayashi, Y.

    2016-09-01

    We present for the first time evidence for the existence of a dynamically refracted primary bow for 9Be+16O scattering. This is demonstrated through the use of coupled channel calculations with an extended double folding potential derived from the density-dependent effective two-body force and precise microscopic cluster wave functions for 9Be. The calculations reproduce the experimental Airy structure in 9Be+16O scattering well. It is found that coupling of a weakly bound 9Be nucleus to excited states plays the role of a booster lens, dynamically enhancing the refraction over the static refraction due to the Luneburg lens mean field potential between the ground states of 9Be and 16O.

  19. Evidence for a dynamically refracted primary bow in weakly bound $^9$Be rainbow scattering from $^{16}$O

    CERN Document Server

    Ohkubo, S

    2016-01-01

    We present for the first time evidence for the existence of a dynamically refracted primary bow for $^{9}$Be+$^{16}$O scattering. This is demonstrated through the use of coupled channel calculations with an extended double folding potential derived from the density-dependent effective two-body force and precise microscopic cluster wave functions for $^{9}$Be. The calculations reproduce the experimental Airy structure in $^{9}$Be+$^{16}$O scattering well.It is found that coupling of a weakly bound $^{9}$Be nucleus to excited states plays the role of a booster lens, dynamically enhancing the refraction over the {\\it static} refraction due to the Luneburg lens mean field potential between the ground states of $^{9}$Be and $^{16}$O.

  20. 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.

  1. Ab initio calculations on the a3∑+u state properties of dimer 7Li2

    Institute of Scientific and Technical Information of China (English)

    Shi De-Heng; Sun Jin-Feng; Zhu Zun-Lue; Liu Yu-Fang

    2007-01-01

    The comparison between single-point energy scanning (SPES) and geometry optimization (OPT) in determining the equilibrium geometry of the a3∑u+ state for 7Li2 is made at numerous basis sets such as 6-311++G(2df), cc-PVTZ,6-311++G(2df, p), 6-311G(3df,3pd), 6-311++G(2df,2pd), D95(3df, 3pd), 6-311++G, DGDZVP, 6-311++G(3df,2pd),6-311G(2df,2pd), D95V++, CEP-121G, 6-311++G(d,p), 6-311++G(2df, pd) and 6-311++G(3df,3pd) in full active space using a symmetry-adapted-cluster/ symmetry-adapted-cluster configuration-interaction (SAC/SAC-CI) method presented in Gaussian03 program package. The difference of the equilibrium geometries obtained by SPES and by OPT is reported. Analyses show that the results obtained by SPES are more reasonable than those obtained by OPT. We have calculated the complete potential energy curves at these sets over a wide internuclear distance range from about 3.0a0to 37.0a0, and the conclusion is that the basis set cc-PVTZ is the most suitable one. With the potential obtained at cc-PVTZ, the spectroscopic data (Te, De, Do, ωe, ωeχe, αe and Be) are computed and they are 1.006 eV, 338.71 cm-1,307.12 cm-1, 64.88 cm-1, 3.41 cm-1, 0.0187 cm-1 and 0.279 cm-1, respectively, which are in good agreement with recent measurements. The total 11 vibrational states are found at J=0. Their corresponding vibrational levels and classical turning points are computed and compared with available RKR data, and good agreement is found. One inertial rotation constant (By) and six centrifugal distortion constants (Dy Hv, Lv, My, Nv and Ov) are calculated.The scattering length is calculated to be -27.138a0, which is in good accord with the experimental data.

  2. 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.

  3. Inclusive measurements of the break-up of 156 MeV 6Li-ions at extreme forward angles and the quasi free break-up model

    International Nuclear Information System (INIS)

    Inclusive alpha particle and deuteron spectra from collisions of 156 MeV 6Li-ions with 12C and 208Pb were measured at extreme forward emission angles including zero degree. The measurements were performed with the Karlsruhe magnetic spectrograph 'Little John' and required an efficient reduction of the background from small-angle scattering. The observed double differential cross sections and angular distributions have been analysed on the basis of Serber's spectator break-up model. When going to angles smaller than grazing, where Coulomb effects are expected to the dominating, transitional features may appear. Corresponding effects probably associated with Coulomb break-up are observed with the 208Pb-target and require a slight extension of the Serber approach. In the case of the 12C-target the break-up cross sections in forward direction seem to reflect the shape of the internal momentum distribution of the alpha particle and deuteron cluster in the 6Li-projectile and are in agreement with a 2S-type wave function. However, at larger angles the shape appears to be distorted, possibly by final state interactions. (orig.)

  4. Thermoluminescent response to thermal neutrons of mixture of CaSO4: Tm and non-luminous 6LiF

    International Nuclear Information System (INIS)

    Thermoluminescent property of the mixture of CaSO4: Tm powder and non-luminous 6LiF powder was studied with a view to developing a personnel monitor for thermal neutrons. Its thermoluminescent response to thermal neutrons as a function of the particle size or the mixing ratio of both powders was investigated theoretically and experimentally. The phosphor sample, which was prepared according to the most favorable conditions that the particle size of both powders was between 100 -- 150 μm and the mixing weight ratio of CaSO4: Tm to 6LiF was 1 : 1, was found to have the following dosimetric properties. (1) The thermoluminescence output is linear against neutron dose in a dose range from 10 μrem up to 6 rem. (2) The thermoluminescent efficiency remains constant even after 5,000 repetitions of exposure-reading-annealing procedure. (3) A thermal neutron dose of 1 mrem can be determined with a standard deviation of 5.2% even under a γ-ray background of 10 mR. (auth.)

  5. 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.

  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 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)

  8. LiPF6/LiBOB混合锂盐改善LiFePO4/石墨动力电池高温循环性能研究%Use of LiPF6/LiBOB blend salt for improving cycling performances of LiFePO4/graphite battery at elevated temperature

    Institute of Scientific and Technical Information of China (English)

    宋海申; 赖延清; 李劼; 刘业翔; 张治安

    2013-01-01

    分别以 LiPF6、LiBOB 和 LiPF6/LiBOB 混合盐为电解质,研究了不同电解液对 LiFePO4/石墨动力电池高温循环性能的影响。结果表明,LiBOB 盐抑制了正极溶铁行为,并提高了正极高温循环充放电效率;由于 LiBOB基电解液对正极的保护及在负极表面良好的成膜作用,使得LiFePO4/石墨电池高温循环性能得到明显改善,但是增大了电池阻抗。LiPF6/Li-BOB混合盐可以发挥 LiBOB盐的优点增加正极稳定性,在石墨表面形成致密的 SEI 膜并能够有效改善电池高温循环性能,同时避免了单纯使用 LiBOB盐时阻抗较高的缺点。使用 LiPF6/LiBOB 混合盐,利用LiPF6盐低阻抗特性及 LiBOB盐对正、负电极的保护作用,可以有效提高电池电化学性能。%LiPF6 ,LiBOB and LiPF6/LiBOB blend salt-based electrolytes were investigated for improving cycling performances of LiFePO4/graphite lithium-ion batteries at elevated temperature.It was demonstrated that dis-solution of Fe from LiFePO4 was depressed in LiBOB based electrolyte,and columbic efficiency of LiFePO4/Li cell at elevated temperature was increased;LiBOB was reduced earlier on anode surface,forming compact SEI layer;and the capacity retention of LiFePO4/graphite cells at 55℃ increases with LiBOB concentration due to protective depositions of LiBOB on cathode surface and the SEI layer on anode surface,while the impedance of the cell is increased.LiPF6/LiBOB blend salt-based electrolyte combines the advantages of the different salts and maximizes the performance of cells.When electrolytes with LiPF6/LiBOB blend salt was used,the LiFe-PO4/graphite cells have excellent capacity retention at 55℃,while the impedance was dramatically decreased.

  9. Coupled channels description of single and mutual excitation in the scatttering of /sup 7/Li from /sup 12/C and sup(24,26)Mg

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J.; Clarke, N.M.; Coopersmith, J.; Griffiths, R.J. (King' s Coll., London (UK). Wheatstone Physics Lab.)

    1982-09-27

    Coupled channels calculations have been made for the scattering of /sup 7/Li from /sup 12/C at 63 and 79 MeV and from sup(24,26)Mg at 88 MeV. The calculations describe, simultaneously, the elastic scattering, excitation of /sup 7/Li to the 478 keV 1/2/sup -/ state, excitation of the target to its first 2/sup +/ state, and the mutual excitation of both projectile and target to their 1/2/sup -/ and 2/sup +/ states respectively. The potentials have been used for the ground states of /sup 7/Li, /sup 12/C and sup(24,26)Mg and also the transition densities to the excited states using a microscopic plus macroscopic prescription. For the mutual excitation, both one-step processes with iota = 0, 2 and 4 and two-step processes were included. The calculations show that the two-step processes are the dominant contribution to the mutual excitation, but at forward angles, the oscillations in the data are only reproduced with the coherent addition of the one-step processes, which are dominated by the iota = 4 contribution. Even when coupling to all single and mutual excitations are included the real potential still requires a normalization of about 0.6. The addition of the quadrupole re-orientation matrix element for the ground state dows not significantly change this value. These calculations confirm that the coupling to the first excited inelastic levels of target and ejectile is not the source of the anomalous M3Y normalization, and that the dominant mode of mutual excitation is a two-step processes. However, direct one-step mutual excitation is important for small angles (THETA approx. <= 20/sup 0/).

  10. Coupled channels description of single and mutual excitation in the scatttering of 7Li from 12C and sup(24,26)Mg

    International Nuclear Information System (INIS)

    Coupled channels calculations have been made for the scattering of 7Li from 12C at 63 and 79 MeV and from sup(24,26)Mg at 88 MeV. The calculations describe, simultaneously, the elastic scattering, excitation of 7Li to the 478 keV 1/2- state, excitation of the target to its first 2+ state, and the mutual excitation of both projectile and target to their 1/2- and 2+ states respectively. The potentials have been used for the ground states of 7Li, 12C and sup(24,26)Mg and also the transition densities to the excited states using a microscopic plus macroscopic prescription. For the mutual excitation, both one-step processes with iota = 0, 2 and 4 and two-step processes were included. The calculations show that the two-step processes are the dominant contribution to the mutual excitation, but at forward angles, the oscillations in the data are only reproduced with the coherent addition of the one-step processes, which are dominated by the iota = 4 contribution. Even when coupling to all single and mutual excitations are included the real potential still requires a normalization of about 0.6. The addition of the quadrupole re-orientation matrix element for the ground state dows not significantly change this value. These calculations confirm that the coupling to the first excited inelastic levels of target and ejectile is not the source of the anomalous M3Y normalization, and that the dominant mode of mutual excitation is a two-step processes. However, direct one-step mutual excitation is important for small angles (THETA approx. 0). (orig.)

  11. Experimental and Calculated Effectiveness of a Radiochromic Dye Film to Stopping 21 MeV 7Li- and 64 MeV 16O Ions

    DEFF Research Database (Denmark)

    Olsen, Kjeld J; Hansen, Johnny

    1984-01-01

    Relative radiation effectiveness, RE, of 21 MeV 7Li and 64 MeV 16O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a δ-ray theory for heavy charged...... in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the δ-ray spectrum...

  12. Branching ratio of 8Be* high excited states in the 10B(dα)2α and 10B(dα)p7Li reaction

    International Nuclear Information System (INIS)

    Three-particle channels of 10B(dα)2α and 10B(dα)p7Li reactions with the excitation of short-living 19.86, 4+ and 20.1 MeV, 2+ state of 8Be* nucleus are investigated under 13.6 MeV incident deuteron energy in kinematically complete experiment. Angular correlation functions for these states and branching ratio by α-particle and proton channels are obtained. Spatial anisotropy of 8Be* nucleus parameter change as of two-cluster non-isolated subsystem is revealed

  13. Investigation of the triton emission asymmetry in the sup 6 Li(n, alpha) sup 3 H reaction with polarized thermal neutrons

    CERN Document Server

    Gledenov, Yu M; Petukhov, A K; Sedyshev, P V; Shulgina, E V; Soldner, T; Vesna, V A; Zimmer, O

    2002-01-01

    An experiment was carried out at the high-intensity polarized cold neutron beam of the PF1B instrument of the ILL reactor, Grenoble, France. As a detector, the 48-section ionization chamber with the sup 6 LiF targets was used. An integral (current) method of the event detection with compensation of the reactor power fluctuation was applied. Special measurement technique was used for minimization and estimation of the possible false effect contribution. A value of the P-odd (sigma sub n , P sub t) correlation has been obtained: alpha sub P sub N = -(7.1 +- 3.9) centre dot 10 sup - sup 8. On the basis of the cluster model, the most accurate at present day estimation of the weak neutral current constant has been given: f subpi <= 1.2 centre dot 10 sup - sup 7.

  14. 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.

  15. 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

  16. Detector for the FSD Fourier-diffractometer based on ZnS(Ag)/6LiF scintillation screen and wavelength shifting fibers readout

    International Nuclear Information System (INIS)

    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 stresses 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)/6LiF 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 the tested modules in comparison with a detector of the previous generation are presented and advantages of the new detector design for high-resolution diffractometry are discussed

  17. Development of an apparatus for cooling 6Li-87Rb Fermi-Bose mixtures in a light-assisted magnetic trap

    CERN Document Server

    Brown-Hayes, M; Kim, W -J; Onofrio, R

    2007-01-01

    We describe an experimental setup designed to produce ultracold trapped gas clouds of fermionic 6Li and bosonic 87Rb. This combination of alkali metals has the potential to reach deeper Fermi degeneracy with respect to other mixtures since it allows for improved heat capacity matching which optimizes sympathetic cooling efficiency. Atomic beams of the two species are independently produced and then decelerated by Zeeman slowers. The slowed atoms are collected into a magneto-optical trap and then transferred into a quadrupole magnetic trap. An ultracold Fermi gas with temperature in the 10^-3 T_F range should be attainable through selective confinement of the two species via a properly detuned laser beam focused in the center of the magnetic trap.

  18. A reanalysis of radioisotope measurements of the $^9$Be$(\\gamma,n)^8$Be cross-section

    CERN Document Server

    Robinson, Alan E

    2016-01-01

    The $^9$Be$(\\gamma,n)^8$Be reaction is enhanced by a near threshold $1/2^+$ state. Contradictions between existing measurements of this reaction cross-section affect calculations of astrophysical r-process yields, dark matter detector calibrations, and the theory of the nuclear structure of $^9$Be. Select well-documented radioisotope $^9$Be$(\\gamma,n)$ source yield measurements have been reanalyzed, providing a set of high-accuracy independently measured cross sections. A Breit-Wigner fit of these corrected measurements yields $E_R=1738.8^{+5.0}_{-4.2}$~keV, $\\Gamma_\\gamma=0.771^{+0.055}_{-0.044}$~eV, and $\\Gamma_n=268^{+40}_{-33}$~keV for the $1/2^+$ state. The fit favors a resonant $1/2^+$ state, but a virtual state is not excluded.

  19. A consistent four-body CDCC model of low-energy reactions: Application to 9Be + 208Pb

    CERN Document Server

    Hussein, M S; Canto, L F

    2015-01-01

    We investigate the $^9$Be + $^{208}$Pb elastic scattering, breakup and fusion at energies around the Coulomb barrier. The three processes are described simultaneously, with identical conditions of calculations. The $^{9}$Be nucleus is defined in an $\\alpha + \\alpha$ + n three-body model, using the hyperspherical coordinate method. We first analyze spectroscopic properties of $^9$Be, and show that the model provides a fairly good description of the low-lying states. The scattering with $^{208}$Pb is then studied with the Continuum Discretized Coupled Channel (CDCC) method, where the $\\alpha+\\alpha$ + n continuum is approximated by a discrete number of pseudostates. Optical potentials for the $\\alpha$+ $^{208}$Pb and n+ $^{208}$Pb systems are taken from the literature. We present elastic-scattering and fusion cross sections at different energies.

  20. Structure and dynamics of homoleptic beryllocenes: a solid-state 9Be and 13C NMR study.

    Science.gov (United States)

    Hung, Ivan; Macdonald, Charles L B; Schurko, Robert W

    2004-11-19

    The correlation between anisotropic 9Be NMR (quadrupolar and chemical shielding) interactions and the structure and dynamics in [Cp2Be], [Cp2*Be], and [(C5Me4H)2Be] is examined by solid-state 9Be NMR spectroscopy, as well as by ab initio and hybrid density functional theory calculations. The 9Be quadrupole coupling constants in the three compounds correspond well to the relative degrees of spherical ground-state electronic symmetry of the environment about beryllium. Theoretical computations of NMR interaction tensors are in excellent agreement with experimental values and aid in understanding the origins of NMR interaction tensors and their correlation to molecular symmetry. Variable-temperature (VT) 9Be and 13C NMR experiments reveal a highly fluxional structure in the condensed phase of [Cp2Be]. In particular, the pathway by which the Cp rings of [Cp2Be] 'invert' coordination modes is examined in detail using hybrid density functional theory in order to inspect variations of the 9Be NMR interaction tensors. The activation energy for the 'inversion' process is found to be 36.9 kJ mol(-1) from chemical exchange analysis of 13C VT CP/MAS NMR spectra. The low-temperature (ca. -100 degrees C) X-ray crystal structures of all three compounds have been collected and refined, and are in agreement with previously reported structures. In addition, the structure of the same Cp2Be crystal was determined at 20 degrees C and displays features consistent with increased intramolecular motion, supporting observations by 9Be VT NMR spectroscopy. PMID:15484199

  1. Study of the role of breakup following neutron transfer in fusion induced by 9Be at near barrier energies

    International Nuclear Information System (INIS)

    The studies on the breakup effects of weakly bound nuclei, both stable and radioactive, on fusion cross section is a subject of contemporary interest. These weakly bound nuclei have low breakup threshold (binding energy) that makes the fusion induced by these nuclei fundamentally different from that induced by tightly bound nuclei. Among these nuclei, the nucleus 9Be is very interesting because it has low break up threshold of 1.67 MeV and has a possible three body n+α+α Borromean structure. So far, numbers of experiments have been carried out to study the fusion reactions induced by 9Be on various targets at near barrier energies

  2. $\\gamma$ -spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li

    CERN Multimedia

    We propose an experiment with MINIBALL coupled to T-REX to investigate n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li. The nuclei of interest will be populated by transfer of a triton into $^{94}$Kr, forming the excited $^{97}$Rb nucleus, followed by the emission of an alpha particle, which will be detected in the Si telescopes of T-REX. The $^{97}$Rb product will evaporate 1 or 2 (with the highest probability) neutrons leading to $^{96}$Rb or $^{95}$Rb, respectively. The aim of the experiment is twofold: \\\\ i) to perform a $\\gamma$- spectroscopy study of $^{95,96}$Rb nuclei with N=58,59, the structure of which is of particular interest in investigating the transition towards stable deformation at N=60, \\\\ ii) to acquire experience in using incomplete fusion reactions with the weakly bound $^{7}$Li target, in order to perform, at a later stage with HIE-ISOLDE, similar measurements induced by n-rich radioactive beams of Sn and Hg, for which at least 5 MeV/nucleon are need...

  3. Measurement of $^{7}$Be(n,$\\alpha$)$^{4}$He and $^{7}$Be(n,p)$^{7}$Li cross-sections for the Cosmological Lithium Problem

    CERN Multimedia

    We propose to measure in the second experimental area of n TOF the $^{7}$Be(n,$\\alpha$)$^{4}$He and $^{7}$Be(n,p)$^{7}$Li reaction in a wide energy range. Both reactions are of interest for the long- standing "Cosmological $^{7}$Li problem" in Big Bang Nucleosynthesis (BBN). The very high specific activity of $^{7}$Be, and the low cross section of the (n,$\\alpha$) reaction make this measurement extremely dicult. As afirst step, we request some beam time for detector tests at EAR2. For the $^{7}$Be(n,p) reaction, previously measured up to 13 keV, the diculty is mostly associated withthe availability of a high-purity $^{7}$Be sample. To this purpose we ask for three shifts of offline ISOLDE mass separation for the preparation of the sample to be used at n TOF. To this end, a prior endorsement by INTC of the scientific validity and feasibility of the proposed measurement is requested, to start activity on the sample production. The present proposal is part of a wider collaborative effort aimed at measuring neutr...

  4. Study of 9Be (d,p0)10Be and 9Be(d,t0)8Be reactions between 0.24 and 3.8 MeV

    International Nuclear Information System (INIS)

    This research thesis addresses the precise study of the mechanism of direct interaction within the frame of the stripping and pick-up theory of distorted waves, and of the involved parameters for the 9Be (d,p0)10Be and 9Be(d,t0)8Be reactions between 0.24 and 3.8 MeV. After a description of the arrangements and methods used to obtain experimental angular distributions on different energy ranges (0.24, 0.7-3.0, and 3.4-3.8 MeV), the author recalls the formalism of the theory of distorted waves within the Born approximation. The author then presents the experimental and theoretical results: angular distributions and excitation functions as far as experimental results are concerned, and deuton elastic scattering and analysis of both reactions as far as theoretical results are concerned. He discusses their correlation

  5. Quasielastic Scattering of the Halo Nucleus 6He at 25 MeV/u from a 9Be Target

    Institute of Scientific and Technical Information of China (English)

    PANG Dan-Yang; ZHANG Gao-Long; HU Qing-Yuan; WANG Jia; A.Ozawa; Y.Yamaguchi; R.Kanungo; D.Fang; I.Tanihata; YE Yan-Lin; JIANG Dong-Xing; ZHENG Tao; WANG Quan-Jin; LI Zhi-Huan; LI Xiang-Qing; GE Yu-Cheng; WU Cui-E

    2004-01-01

    @@ The differential cross sections of quasielastic scattering of a 25 MeV/u 6He from 9Be target have been measured.The double-folding model approach is applied to generate the real part of the optical potential The imaginary potential parameters as well as some of the real potential parameters are studied in comparison with the experimental data. The effect of the unstable nucleus is discussed.

  6. Analysis of longitudinal momentum distribution of 10Be in 9Be(11Be, 10Be)X reaction

    International Nuclear Information System (INIS)

    We have analyzed the longitudinal momentum distribution of 10Be fragment coming from one neutron stripping from 11Be on 9Be target at 60AMeV beam energy within the framework of zero and first order eikonal approximation. It has been found that the inclusion of first order correction term in the eikonal approximation results in a substantial improvement in the matching between the predicted and experimental results especially in tail region of the spectrum. (author)

  7. An angular momentum selection rule and the 9Be(π+,p)8Be reaction at 50 MeV

    International Nuclear Information System (INIS)

    Angular distributions have been measured at 50 MeV for the 9Be(π+,p)8Be reaction leading to the 0+, 2+ and 4+ states of 8Be. An angular momentum selection rule is considered in order to account for the preferential excitation of high spin states. Two-step processes in the framework of the DWBA and momentum sharing in the two-nucleon model are also discussed

  8. Sequential mechanism for the Li7 (He3, α)6 Li(d)α reaction at incident energy between 2.5 and 11.5 MeV

    International Nuclear Information System (INIS)

    A strictly sequential mechanism appears to appropriate for the Li7 (3He,α)6Li(d)α reaction in the energy range between 2.5 and 11.5 MeV. It can be described by a first direct emission mechanism and a second delayed emission

  9. 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

  10. A Comprehensive Theoretical Analysis of 6,7Li + 64Zn Elastic Scattering in a Wide Angular Range Around the Coulomb Barrier

    Science.gov (United States)

    Ibraheem, Awad A.; Aygun, M.

    2016-08-01

    In this paper, the elastic scattering angular distributions of 6,7Li on 64Zn have been investigated by using various nuclear potentials. For this, we use the phenomenological Woods-Saxon potential, the real double folding potential with the density-independent M3Y effective interaction supplemented with an imaginary part in Woods-Saxon form and the double folding potentials multiplied with a normalization factor of the real and imaginary parts via the density-independent and CDM3Y6 density-dependent versions of the M3Y effective interaction have been used. The results have been compared with each other as well as with the experimental data. It has been observed that the agreement between the theoretical results and earlier reported data is perfect. Finally, the change of the total reaction cross sections with energy has been investigated.

  11. A novel laser-collider used to produce monoenergetic 13.3 MeV (7)Li (d, n) neutrons.

    Science.gov (United States)

    Zhao, J R; Zhang, X P; Yuan, D W; Li, Y T; Li, D Z; Rhee, Y J; Zhang, Z; Li, F; Zhu, B J; Li, Yan F; Han, B; Liu, C; Ma, Y; Li, Yi F; Tao, M Z; Li, M H; Guo, X; Huang, X G; Fu, S Z; Zhu, J Q; Zhao, G; Chen, L M; Fu, C B; Zhang, J

    2016-01-01

    Neutron energy is directly correlated with the energy of the incident ions in experiments involving laser-driven nuclear reactions. Using high-energy incident ions reduces the energy concentration of the generated neutrons. A novel "laser-collider" method was used at the Shenguang II laser facility to produce monoenergetic neutrons via (7)Li (d, n) nuclear reactions. The specially designed K-shaped target significantly increased the numbers of incident d and Li ions at the keV level. Ultimately, 13.3 MeV neutrons were obtained. Considering the time resolution of the neutron detector, we demonstrated that the produced neutrons were monoenergetic. Interferometry and a Multi hydro-dynamics simulation confirmed the monoenergetic nature of these neutrons. PMID:27250660

  12. A novel laser-collider used to produce monoenergetic 13.3 MeV 7Li (d, n) neutrons

    Science.gov (United States)

    Zhao, J. R.; Zhang, X. P.; Yuan, D. W.; Li, Y. T.; Li, D. Z.; Rhee, Y. J.; Zhang, Z.; Li, F.; Zhu, B. J.; Li, Yan F.; Han, B.; Liu, C.; Ma, Y.; Li, Yi F.; Tao, M. Z.; Li, M. H.; Guo, X.; Huang, X. G.; Fu, S. Z.; Zhu, J. Q.; Zhao, G.; Chen, L. M.; Fu, C. B.; Zhang, J.

    2016-01-01

    Neutron energy is directly correlated with the energy of the incident ions in experiments involving laser-driven nuclear reactions. Using high-energy incident ions reduces the energy concentration of the generated neutrons. A novel “laser-collider” method was used at the Shenguang II laser facility to produce monoenergetic neutrons via 7Li (d, n) nuclear reactions. The specially designed K-shaped target significantly increased the numbers of incident d and Li ions at the keV level. Ultimately, 13.3 MeV neutrons were obtained. Considering the time resolution of the neutron detector, we demonstrated that the produced neutrons were monoenergetic. Interferometry and a Multi hydro-dynamics simulation confirmed the monoenergetic nature of these neutrons. PMID:27250660

  13. NMR spin-lattice relaxation study of 7Li and 93Nb nuclei in Ti- or Fe-doped LiNbO3:Mg single crystals

    Directory of Open Access Journals (Sweden)

    Tae Ho Yeom

    2016-04-01

    Full Text Available In this study, to understand the effects of paramagnetic impurities, we investigated the temperature dependent of the spin-lattice relaxation times of pure LiNbO3, LiNbO3:Mg, LiNbO3:Mg/Ti, LiNbO3:Mg/Fe, and LiNbO3:Mg/Fe (thermally treated at 500°C single crystals. The results for the LiNbO3:Mg single crystals doped with Fe3+ or Ti3+ are discussed with respect to the site distribution and atomic mobility of Li and Nb. In addition, the effects of a thermal treatment on LiNbO3:Mg/Fe single crystals were examined based on the T1 analysis of 7Li and 93Nb. It was found that the presence of impurities in the crystals induced systematic changes of activation energies concerning atomic mobility.

  14. In situ7Li and 133Cs nuclear magnetic resonance investigations on the role of Cs+ additive in lithium-metal deposition process

    Science.gov (United States)

    Hu, Jian Zhi; Zhao, Zhenchao; Hu, Mary Y.; Feng, Ju; Deng, Xuchu; Chen, Xilin; Xu, Wu; Liu, Jun; Zhang, Ji-Guang

    2016-02-01

    Cesium ion (Cs+) has been reported to be an effective electrolyte additive to suppress Li dendrite growth which prevents the application of lithium (Li) metal as an anode for rechargeable Li batteries. In this work, we investigated the effect of Cs+ additive on Li depositions using quantitative in situ7Li and 133Cs nuclear magnetic resonance (NMR) with planar symmetric Li cells. It's found that the addition of Cs+ can significantly enhance both the formation of well aligned Li nanorods and reversibility of the Li electrode. In situ133Cs NMR directly confirms that Cs+ migrates to Li electrode to form a positively charged electrostatic shield during the charging process. Much more electrochemical "active" Li was found in Li films deposited with Cs+ additive, while more electrochemical "dead" and thicker Li rods were identified in Li films deposited without Cs+. Combining the in situ and the previous ex-situ results, a Li deposition model has been proposed to explain these observations.

  15. A Comprehensive Theoretical Analysis of 6,7Li + 64Zn Elastic Scattering in a Wide Angular Range Around the Coulomb Barrier

    Science.gov (United States)

    Ibraheem, Awad A.; Aygun, M.

    2016-06-01

    In this paper, the elastic scattering angular distributions of 6,7Li on 64Zn have been investigated by using various nuclear potentials. For this, we use the phenomenological Woods-Saxon potential, the real double folding potential with the density-independent M3Y effective interaction supplemented with an imaginary part in Woods-Saxon form and the double folding potentials multiplied with a normalization factor of the real and imaginary parts via the density-independent and CDM3Y6 density-dependent versions of the M3Y effective interaction have been used. The results have been compared with each other as well as with the experimental data. It has been observed that the agreement between the theoretical results and earlier reported data is perfect. Finally, the change of the total reaction cross sections with energy has been investigated.

  16. Identification of Li-Ion Battery SEI Compounds through (7)Li and (13)C Solid-State MAS NMR Spectroscopy and MALDI-TOF Mass Spectrometry.

    Science.gov (United States)

    Huff, Laura A; Tavassol, Hadi; Esbenshade, Jennifer L; Xing, Wenting; Chiang, Yet-Ming; Gewirth, Andrew A

    2016-01-13

    Solid-state (7)Li and (13)C MAS NMR spectra of cycled graphitic Li-ion anodes demonstrate SEI compound formation upon lithiation that is followed by changes in the SEI upon delithiation. Solid-state (13)C DPMAS NMR shows changes in peaks associated with organic solvent compounds (ethylene carbonate and dimethyl carbonate, EC/DMC) upon electrochemical cycling due to the formation of and subsequent changes in the SEI compounds. Solid-state (13)C NMR spin-lattice (T1) relaxation time measurements of lithiated Li-ion anodes and reference poly(ethylene oxide) (PEO) powders, along with MALDI-TOF mass spectrometry results, indicate that large-molecular-weight polymers are formed in the SEI layers of the discharged anodes. MALDI-TOF MS and NMR spectroscopy results additionally indicate that delithiated anodes exhibit a larger number of SEI products than is found in lithiated anodes. PMID:26653886

  17. Radiative transition probabilities for the B 1PI - X 1SIGMA+ and B 1PI - A 1SIGMA+ of 7LiH

    International Nuclear Information System (INIS)

    The recently reported (J. Chem. Phys. 66, 5412 (1977)) hybrid potential curves for the X 1Σ+ and A 1Σ+ states of LiH and the herein reported hybrid potential curve for the B 1Pi state of LiH are combined with the ab initio transition moments of Docken and Hinze (J. Chem. Phys. 57, 4936 (1972)) to calculate radiative transition probabilities between all B 1Pi (v' less than or equal to 2) and all X 1Σ+ (v'' less than or equal to 23) and A 1Σ+ (v'' less than or equal to 26) vibrational levels of 7LiH. The strongest single emission band found is the B 1Pi (v' = 2) → X 1Σ+ (v'' = 23) band between the highest ''long-range'' levels in each potential. For all B 1Pi levels, the emission is dominated by B → X rather than B → A emission

  18. Ab initio calculations of accurate dissociation energy and analytic potential energy function for the second excited state B1П of 7LiH

    Institute of Scientific and Technical Information of China (English)

    Shi De-Heng; Liu Yu-Fang; Sun Jin-Feng; Zhu Zun-Lùe; Yang Xiang-Dong

    2006-01-01

    The reasonable dissociation limit of the second excited singlet state B1П of 7LiH molecule is obtained. The obtained over the internuclear distance ranging from about 0.10 nm to 0.54 nm, and has a least-square fit to the analytic compared with previous theoretical results. The equilibrium internuclear distance obtained by geometry optimization is found to be quite different from that obtained by single-point energy scanning under the same calculation condition.comparison of the theoretical calculations of dissociation energies, equilibrium interatomic distances and the analytic potential energy function with those obtained by previous theoretical results clearly shows that the present work is more theories.

  19. Detection of thermal neutrons using ZnS(Ag):6LiF neutron scintillator read out with WLS fibers and SiPMs

    Science.gov (United States)

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

    2016-07-01

    In this paper we present the development of a one-dimensional multi-channel thermal neutron detection system for the application in neutron scattering instrumentation, e.g. strain-scanning diffractometers. The detection system is based on ZnS(Ag):6LiF neutron scintillator with embedded WLS fibers which are read out with a SiPM. A dedicated signal processing system allows us to suppress the SiPM dark counts and to extract the signals from the neutron absorption events. For a single-channel detection unit which represents the elementary building block of this detection system we achieved a neutron detection efficiency of ~65% at 1.2 Å, a background count rate <10-3 Hz and a gamma-sensitivity <10-6 (measured with a 60Co source), while the dead time is ~20 μs and the multi-count ratio is < 1 %. This performance was achieved even for SiPM dark count rates of up to ~2 MHz.

  20. Isotopic Distributions of the l8N Fragmentation Products in Coincidence with Neutrons on Targets 197Au and 9Be

    Institute of Scientific and Technical Information of China (English)

    李湘庆; 江栋兴; 叶沿林; 华辉; 陈陶; 李智焕; 葛愉成; 王全进; 吴和宇; 靳根明; 段利敏; 肖志刚; 王宏伟; 李祖玉; 王素芳

    2002-01-01

    We present the experimental isotopic distributions of the 18 N projectile fragmentation products Li, Be,B and Cin coincidence with neutrons, as well as the inclusive ones on 197 Au and 9Be targets. In the framework of theabrasion-ablation model, these distributions are calculated for various nucleon density distributions of the projec-tile. The comparison with experimental isotopic distributions of the projectile-like fragments in coincidence withneutrons shows that the information on the nucleon density distribution of the 18N projectile can be extracted.

  1. Measurement of the Breakup Cross Sections in 6He+9Be Reaction at 25 MeV/Nucleon

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; HU Qing-Yuan; WU Cui-E; A. Ozawa; Y. Yamaguchi; R. Kanungo; D. Fang; I. Tanihata; YE Yan-Lin; JIANG Dong-Xing; ZHANG Gao-Long; PANG Dan-Yang; LI Zhi-Huan; ZHENG Tao; LI Xiang-Qing; WANG Quan-Jin

    2005-01-01

    @@ The breakup reaction cross sections were measured for the reaction of 6He at 25 MeV/nucleon from 9Be target with intensity of 105 pps. By fitting the energy spectra of breakup α particles with Gaussian functions, the angular distribution of differential cross sections in the laboratory system has been extracted and compared with the Serber model calculations. The good agreement between the calculation and the experimental data favours a dominant configuration of the 4He core plus valence neutrons for the structure of 6He.

  2. Above threshold s-wave resonances illustrated by the 1/2$^+$ states in $^9$Be and $^9$B

    OpenAIRE

    Garrido, E; Fedorov, D. V.; Jensen, A. S.

    2010-01-01

    We solve the persistent problem of the structure of the lowest $1/2^+$ resonance in $^9$Be which is important to bridge the A=8 gap in nucleosynthesis in stars. We show that the state is a genuine three-body resonance even though it decays entirely into neutron-$^8$Be relative s-waves. The necessary barrier is created by "dynamical" evolution of the wave function as the short-distance $\\alpha$-$^5$He structure is changed into the large-distance n-$^8$Be structure. This decay mechanism leads t...

  3. Fuskite® preliminary experimental tests based on permeation against vacuum for hydrogen recovery as a potential application in Pb15.7Li loop systems.

    Energy Technology Data Exchange (ETDEWEB)

    Sacristán, R., E-mail: mrosa.sacristan@sener.es [SENER Ingeniería y Sistemas, C/ Provença 392, 5a, 08025 Barcelona (Spain); Veredas, G. [EURATOM-CIEMAT Fusion Assoc., Fusion Technology Division, Av. Complutense 40, 28040 Madrid (Spain); Bonjoch, I. [SENER Ingeniería y Sistemas, C/ Provença 392, 5a, 08025 Barcelona (Spain); Peñalva, I. [UPV/EHU, Departamento de Ingeniería Nuclear y Mecánica de Fluidos, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Calderón, E. [SENER Ingeniería y Sistemas, C/ Provença 392, 5a, 08025 Barcelona (Spain); Alberro, G. [UPV/EHU, Departamento de Ingeniería Nuclear y Mecánica de Fluidos, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Balart, D. [SENER Ingeniería y Sistemas, Avda. Zugazarte 56, 48930 Las Arenas, Vizcaya (Spain); Sarrionandia-Ibarra, A. [UPV/EHU, Departamento de Ingeniería Nuclear y Mecánica de Fluidos, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Pérez, V. [SENER Ingeniería y Sistemas, Avda. Zugazarte 56, 48930 Las Arenas, Vizcaya (Spain); Ibarra, A. [EURATOM-CIEMAT Fusion Assoc., Fusion Technology Division, Av. Complutense 40, 28040 Madrid (Spain); Legarda, F. [UPV/EHU, Departamento de Ingeniería Nuclear y Mecánica de Fluidos, Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2014-10-15

    Highlights: • Full material characterization as far as hydrogen transport properties are concern. • Quantification of permeator leaks and material degasification. • Analysis of H{sub 2} recovered by means of permeation against vacuum in different conditions. • Hydrogen recovery efficiencies determination. - Abstract: Tritium recovery in fusion reactors is one of the main goals in R and D, as a limited inventory is available and its uneconomic production. That is the reason why efficient technologies are indispensable to be developed in order to achieve fast tritium recovery and its subsequent reuse in the system for increasing its self-sufficiency. In this work a flexible tritium recovery demonstrator prototype based on permeation against vacuum concept has been designed and manufactured, as well as all necessary equipment for a Pb15.7Li loop implementation in order to test and demonstrate that an in-pipe integrated solution is possible, and at the same time, to validate the manufacturing process. Thus, efficient rates for more optimized future models could be then extrapolated. The aim of this paper is to show the different testing results that have been carried out in this research project. These results include permeation properties of the material considered for the permeator, as long as it has been manufactured with a novel technique, Selective Laser Melting. They also include vacuum tests on the permeator to quantify possible leakages and to set up and analyze the capability to generate vacuum inside the permeator, and finally, permeation tests with the prototype, in a first stage with a gas mixture of hydrogen and argon inside the loop instead of Pb15.7Li.

  4. In situ 7Li and 133Cs Nuclear Magnetic Resonance Investigations on the Role of Cs+ Additive in Lithium-Metal Deposition Process

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Z.; Zhao, Zhenchao; Hu, Mary Y.; Feng, Ju; Deng, Xuchu; Chen, Xilin; Xu, Wu; Liu, Jun; Zhang, Jiguang

    2016-02-01

    Application of Li metal electrode in rechargeable lithium battery is hindered by safety concerns due to dendritic growth on the electrode over several charge-discharge cycles. We have found previously that adding low concentration Cs+ in electrolytes can promote smooth deposition of lithium onto metal electrode during repeated charge-discharge cycling using idea Li|Cu battery without the using of a separator. In this work, quantitative in situ 7Li and 133Cs NMR investigations using real planar symmetric lithium battery cells with and without Cs+ additives were carried out. It is found that the deposited lithium atoms on electrodes are highly porous. Detailed analysis of the data were carried out by separating the 7Li signal from deposited lithium that was oriented parallel to the electrode surface with the signal from the Li-metal nanorodes oriented perpendicular or nearly perpendicular to the electrode surface. The results demonstrate that addition of Cs+ can significantly enhance both the formation of uniform Li nanorods, and the reversibility of electrode. In situ 133Cs NMR directly confirms that Cs+ migrates to the electrode to form a positively charged electrostatic shield during cycling process. Combining the quantitative analysis of the orientation dependent signals of deposited metal Li and previous ex-situ results, different Li deposition models are proposed. During cycling process, more “active” lithium participates in the Li transfer between the electrode and nanorods for the battery with Cs+, while for the battery without Cs+ more dead and thinker lithium rods are formed and Li transfer between dendrites from different electrodes dominates.

  5. Fuskite® preliminary experimental tests based on permeation against vacuum for hydrogen recovery as a potential application in Pb15.7Li loop systems

    International Nuclear Information System (INIS)

    Highlights: • Full material characterization as far as hydrogen transport properties are concern. • Quantification of permeator leaks and material degasification. • Analysis of H2 recovered by means of permeation against vacuum in different conditions. • Hydrogen recovery efficiencies determination. - Abstract: Tritium recovery in fusion reactors is one of the main goals in R and D, as a limited inventory is available and its uneconomic production. That is the reason why efficient technologies are indispensable to be developed in order to achieve fast tritium recovery and its subsequent reuse in the system for increasing its self-sufficiency. In this work a flexible tritium recovery demonstrator prototype based on permeation against vacuum concept has been designed and manufactured, as well as all necessary equipment for a Pb15.7Li loop implementation in order to test and demonstrate that an in-pipe integrated solution is possible, and at the same time, to validate the manufacturing process. Thus, efficient rates for more optimized future models could be then extrapolated. The aim of this paper is to show the different testing results that have been carried out in this research project. These results include permeation properties of the material considered for the permeator, as long as it has been manufactured with a novel technique, Selective Laser Melting. They also include vacuum tests on the permeator to quantify possible leakages and to set up and analyze the capability to generate vacuum inside the permeator, and finally, permeation tests with the prototype, in a first stage with a gas mixture of hydrogen and argon inside the loop instead of Pb15.7Li

  6. Cell killing, nuclear damage and apoptosis in Chinese hamster V79 cells after irradiation with heavy-ion beams of (16)O, (12)C and (7)Li.

    Science.gov (United States)

    Pathak, Rupak; Dey, Subrata Kumar; Sarma, Asiti; Khuda-Bukhsh, Anisur Rahman

    2007-08-15

    Chinese hamster V79 cells were exposed to high LET (linear energy transfer) (16)O-beam (625keV/mum) radiation in the dose range of 0-9.83Gy. Cell survival, micronuclei (MN), chromosomal aberrations (CA) and induction of apoptosis were studied as a follow up of our earlier study on high LET radiations ((7)Li-beam of 60keV/mum and (12)C-beam of 295keV/mum) as well as (60)Co gamma-rays. Dose dependent decline in surviving fraction was noticed along with the increase of MN frequency, CA frequency as well as percentage of apoptosis as detected by nuclear fragmentation assay. The relative intensity of DNA ladder, which is a useful marker for the determination of the extent of apoptosis induction, was also increased in a dose dependent manner. Additionally, expression of tyrosine kinase lck-1 gene, which plays an important role in response to ionizing radiation induced apoptosis, was increased with the increase of radiation doses and also with incubation time. The present study showed that all the high LET radiations were generally more effective in cell killing and inflicting other cytogenetic damages than that of low LET gamma-rays. The dose response curves revealed that (7)Li-beam was most effective in cell killing as well as inducing other nuclear damages followed by (12)C, (16)O and (60)Co gamma-rays, in that order. The result of this study may have some application in biological dosimetry for assessment of genotoxicity in heavy ion exposed subjects and in determining suitable doses for radiotherapy in cancer patients where various species of heavy ions are now being generally used.

  7. Computing the Vibrational and Vibrational-rotational Energy Eigenvalues of 7Li2 by the Symplectic Scheme-matrix Algorithm%计算7Li2振动能级煌振动-转动能级的辛格式矩阵法

    Institute of Scientific and Technical Information of China (English)

    何建锋; 刘学深; 丁培柱

    2004-01-01

    利用辛格式矩阵法计算了双原子分子7Li2在A1∑+u态的振动能级和振动-转动能级,并与Ley-Koo等的计算结果作了比较.结果显示,辛格式矩阵法是收敛的和可靠的,是计算双原子分子的振动能级和振动-转动能级的合理的数值方法.

  8. Thermal neutron radiative cross sections for Li,76,9Be,B,1110,C,1312, and N,1514

    Science.gov (United States)

    Firestone, R. B.; Revay, Zs.

    2016-05-01

    Total thermal radiative neutron cross sections have been measured on natural and enriched isotopic targets containing Li,76,9Be,B,1110,C,1312, and N,1514 with neutron beams from the Budapest Reactor. Complete neutron capture γ -ray decay schemes were measured for each isotope. Absolute transition probabilities have been determined by a least-squares fit of the transition intensities, corrected for internal conversion, to the (n ,γ ) decay schemes. The γ -ray cross sections were standardized using stoichiometric compounds containing both the isotope of interest and another element whose γ -ray cross sections are well known. Total cross sections σ0 were then determined for each isotope from the γ -ray cross sections and transition probabilities. For the 11B(n ,γ )12B reaction decay transition probabilities were determined for the γ rays from 12B (t1 /2=20.20 ms) β- decay.

  9. Fluctuations on the X-ray intensity beam using a portable X-ray probe based on {sup 6}LiI(Eu) crystal

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Geraldo P.; Oliveira, Arno H. [Universidade Federal de Minas Gerais (PCTN/UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares; Carneiro, Andre C.; Carneiro, Clemente J.G.; Milian, Felix M.; Velasco, Fermin G., E-mail: fermin@uesc.b [Universidade Estadual de Santa Cruz (CPqCTR/UESC), Ilheus, BA (Brazil). Centro de Pesquisa em Ciencias e Tecnologias das Radiacoes

    2011-07-01

    X-rays are produced by accelerating electrons with a high voltage and allowing them to collide with a metal target. This high voltage presents fluctuations that define peak, minimum, and average voltages. Different voltages are applied to the X-ray tube depending on the radiographic applications. A rectifier circuit converts the alternating high voltage to unidirectional high voltage to accelerate electrons in this tube. The fluctuations on the energy in the electron beam depend on the mode of rectification. Both energy of the electrons and X rays intensity fluctuates. A portable probe built with a {sup 6}LiI(Eu) detector coupled to a 10 m light guide and a Hamamatsu photon counting head H9319 was used to measuring X ray intensities. This system is designed to collect up to 10000 counts in intervals of 10 ms to 1 s. Counts were accumulated in time intervals of 10 ms during 10 s. The system starts the count before activating the X-ray apparatus, which is on during a time interval of 100ms. During this period, counts may overflow in consequence high voltage was adjusted to be 40kV, in order to avoid such a problem. For each of these points dose was measured using an ionization chamber. The objectives of this work are to study fluctuations on the X-ray beam and to calibrate the portable probe for measuring radiation doses. Counting rates measured for each 10 ms presented strong variations due to high voltages fluctuations. Both dose and counting rate when correlated with distances between source and detector followed the inverse square law and presented values of R2 near of unit. A calibration curve of the portable system for dose measurements showed also R2 value near of unity. (author)

  10. Fluctuations on the X-ray intensity beam using a portable X-ray probe based on 6LiI(Eu) crystal

    International Nuclear Information System (INIS)

    X-rays are produced by accelerating electrons with a high voltage and allowing them to collide with a metal target. This high voltage presents fluctuations that define peak, minimum, and average voltages. Different voltages are applied to the X-ray tube depending on the radiographic applications. A rectifier circuit converts the alternating high voltage to unidirectional high voltage to accelerate electrons in this tube. The fluctuations on the energy in the electron beam depend on the mode of rectification. Both energy of the electrons and X rays intensity fluctuates. A portable probe built with a 6LiI(Eu) detector coupled to a 10 m light guide and a Hamamatsu photon counting head H9319 was used to measuring X ray intensities. This system is designed to collect up to 10000 counts in intervals of 10 ms to 1 s. Counts were accumulated in time intervals of 10 ms during 10 s. The system starts the count before activating the X-ray apparatus, which is on during a time interval of 100ms. During this period, counts may overflow in consequence high voltage was adjusted to be 40kV, in order to avoid such a problem. For each of these points dose was measured using an ionization chamber. The objectives of this work are to study fluctuations on the X-ray beam and to calibrate the portable probe for measuring radiation doses. Counting rates measured for each 10 ms presented strong variations due to high voltages fluctuations. Both dose and counting rate when correlated with distances between source and detector followed the inverse square law and presented values of R2 near of unit. A calibration curve of the portable system for dose measurements showed also R2 value near of unity. (author)

  11. Neutron dose estimation via LET spectrometry using CR-39 detector for the reaction 9 Be (p, n

    Directory of Open Access Journals (Sweden)

    G S Sahoo

    2014-01-01

    Full Text Available CR-39 detectors, widely used for neutron dosimetry in accelerator radiation environment, have also been applied in tissue microdosimetry by generating the linear energy transfer (LET spectrum. In this work, the neutron dose has been estimated via LET spectrometry for 9 Be (p, n reaction which is useful for personnel monitoring around particle accelerators and accelerator based therapy facilities. Neutrons were generated by the interaction of protons of 6 different energies from 4-24 MeV with a thick Be target. The LET spectra were obtained from the major and minor radii of each track and the thickness of removed surface. From the LET spectra, the absorbed dose (DLET and the dose equivalent (HLET were estimated using Q-L relationship as given by International Commission on Radiological Protection (ICRP 60. The track density in CR-39 detector and hence the neutron yield was found to be increasing with the increase in projectile (proton energy. Similar observations were also obtained for absorbed dose (DLET and dose equivalents (HLET .

  12. Photoneutron cross sections measurements in 9Be, 13C e 17O with thermal neutron capture gamma-rays

    International Nuclear Information System (INIS)

    Photoneutron cross sections measurements of 9Be, 13C and 17O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4π geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm3, 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  13. Radiative neutron capture on 9be, 14c, 14n, 15n and 16o at thermal and astrophysical energies

    CERN Document Server

    Dubovichenko, Sergey; Afanasyeva, Nadezhda

    2013-01-01

    The total cross sections of the radiative neutron capture processes on 9Be, 14C, 14N, 15N, and 16O are described in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. The continued interest in the study of these reactions is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This article is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big Bang models.

  14. Statistical theory of light-nucleus reactions and application to the 9Be (p,xn) reaction

    Science.gov (United States)

    Sun, Xiaojun; Zhang, Jingshang

    2016-01-01

    A statistical theory of light nucleus reactions (STLN) is proposed to describe both neutron and light charged particle induced nuclear reactions with 1 p -shell light nuclei involved. The dynamics of STLN is described by the unified Hauser-Feshbach and exciton model, in which the angular momentum and parity conservations are strictly considered in equilibrium and pre-equilibrium processes. The Coulomb barriers of the incoming and outgoing charged particles, which significantly influence the open channels of the reaction, can be reasonably considered in the incident channel and different outgoing channels. In kinematics, the recoiling effects in various emission processes are strictly taken into account. The analytical double-differential cross sections of the reaction products in sequential and simultaneous emission processes are obtained in terms of the new integral formula proposed in our recent paper [Phys. Rev. C 92, 061601(R) (2015), 10.1103/PhysRevC.92.061601]. Taking the 9Be(p ,x n ) reaction as an example, we calculate the double-differential cross sections of outgoing neutrons and charged particles using the punf code in the frame of STLN. The existing experimental double-differential cross sections of neutrons at Ep=18 MeV can be remarkably well reproduced, which indicates that the punf code is a powerful tool to set up "file-6" in the reaction data library for light charged particle induced nuclear reactions with 1 p -shell light nuclei involved.

  15. Study of 12Be using the 11Be(9Be,8Be) transfer reaction at TRIUMF ISAC-II

    Science.gov (United States)

    Braid, Ryan; Sarazin, Fred; TIGRESS Collaboration; (PCB)2 Collaboration

    2015-10-01

    Recent results at TRIUMF and NSCL have called into question the structure of 12Be, therefore another look at this nucleus is desirable. The structure is important information for theoretical models, since it constrains the mechanism that produces parity inversion in 11Be. The 12Be structure was probed in July 2014 using the (PCB)2 array (Printed Circuit Board Based Charged Particle) inside TIGRESS (TRIUMF - ISAC Gamma Ray Escape Suppressed Spectrometer) at TRIUMF using the 11Be(9Be,8Be)12Be reaction at 55 MeV in inverse kinematics. A second set of data at 30 MeV was collected. This reaction has numerous advantages over the traditional (d,p) method, foremost of which is the 8Be --> 2 α breakup since it allows for very clean identification and tagging. Additionally, TIGRESS will allow precise γ-tagging for the excited states. The initial data and analysis will be presented in this talk. This work is partially supported by the US Department of Energy through Grant/Contract No. DE-FG03-93ER40789 (Colorado School of Mines).

  16. 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.

  17. Nuclear shadowing in polarized DIS on ^6LiD at small x and its effect on the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2)

    OpenAIRE

    Guzey, V.

    2000-01-01

    We consider the effect of nuclear shadowing in polarized deep inelastic scattering (DIS) on ^6LiD at small Bjorken x and its relevance to the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2). Using models, which describe nuclear shadowing in unpolarized DIS, we demonstrate that the nuclear shadowing correction to g_{1}^{d}(x,Q^2) is significant.

  18. Quasi-monoenergetic neutron energy spectra for 246 and 389 MeV (7)Li(p,n) reactions at angles from 0 degrees to 300 degrees

    CERN Document Server

    Iwamoto, Y; Nakamura, T; Nakashima, H; Mares, V; Itoga, T; Matsumoto, T; Nakane, Y; Feldbaumer, E; Jaegerhofer, L; Pioch, C; Tamii, A; Satoh, D; Masuda, A; Sato, T; Iwase, H; Yashima, H; Nishiyama, J; Hagiwara, M; Hatanaka, K; Sakamoto, Y

    2011-01-01

    The authors measured the neutron energy spectra of a quasi-monoenergetic (7)Li(p,n) neutron source with 246 and 389 MeV protons set at seven angles (0 degrees, 2.5 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees and 30 degrees), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. The energy spectra of the source neutrons were precisely deduced down to 2 MeV at 0 degrees and 10 MeV at other angles. The cross-sections of the peak neutron production reaction at 0 degrees were on the 35-40 mb line of other experimental data, and the peak neutron angular distribution agreed well with the Taddeucci formula. Neutron energy spectra below 100 MeV at all angles were comparable, but the shapes of the continuum above 150 MeV changed considerably with the angle. In order to consider the correction required to derive the response in the peak region from the measured total response for high-energy neutron monitors such as DAR...

  19. R-matrix analysis of the 12C(α,γ) reaction with inputs from 12C(7Li,t)16O∗ transfer reaction

    International Nuclear Information System (INIS)

    The 12C(α,γ) reaction at 300 keV determines the ratio of 16O to 12C abundance at the end of helium burning in stars. The direct measurement of the cross-section of this reaction is almost impossible with the presently available techniques. Extrapolation of the cross-section or the astrophysical S-factor from higher energy data is presently adopted. There are several direct measurements of the 12C(α,γ) reaction but the lowest energy upto which measurement has been done is only upto 1 MeV. R-matrix extrapolation of the E2 and E1 capture data is complicated by the lack of knowledge of the cluster structure of the 6.92 MeV (2+) and 7.12 MeV (1-) states of 16O. In this paper we report a study of the E2 capture data that is analysed with the ANC of the 6.92 MeV state determined from 12C(7Li,t) alpha transfer measurements

  20. Formation of ultracold 7Li85Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy

    International Nuclear Information System (INIS)

    We report the formation of ultracold 7Li85Rb molecules in the a3Σ+ electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ∼62 cm−1 below the 7Li 2s 2S1/2 + 85Rb 5p 2P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a3Σ+ state and excited electronic 33Π and 43Σ+ states and identify a3Σ+ (v″ = 7–13), 33Π (vΠ′ = 0–10), and 43Σ+ (vΣ′ = 0–5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state

  1. Manufacturing of thin films of boron for the measurement of the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Smilgys, Barbara; Oliveira, Sandro Guedes de; Hadler Neto, Julio Cesar; Vellame, Igor Alencar [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Soares, Cleber Jose; Salim, Leonardo Alfredo [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Coelho, Paulo Rogerio Pinto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2011-07-01

    Full text: The Boron Neutron Capture Therapy (BNCT) is considered to be a possible treatment for different types of aggressive cancers located in areas of difficult access or which already have metastasis. The working principle of this therapy is the selective delivery of a greater amount of boron to the tumor cells than to the healthy ones, followed by the neutron irradiation that will induce the emission of {alpha} particles through the {sup 10}B(n, {alpha}){sup 7} Li reaction used in BNCT reaction. The high energy deposition of the product particles causes the death of the cells and this therapy becomes much effective if the healthy tissue is less exposed to this radiation. The objective of this work is to develop a method for measuring the rate of this reaction by using thin films of boron. We have manufactured thin films with different concentrations of boron deposited on mica and the thin films were exposed to different irradiation time intervals at the reactor IEA-R1 located at IPEN, Sao Paulo. Here we show our first results on the density and uniformity of the thin films, where the detection of the particles is made using plastic track detectors (CR-39) which have their structures damaged by the passage of ions. (author)

  2. Spectroscopy of particle-phonon coupled states in $^{133}$Sb by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li

    CERN Multimedia

    We propose to investigate, with MINIBALL coupled to T-REX, the one-valence-proton $^{133}$Sb nucleus by the cluster transfer reaction of $^{132}$Sn on $^{7}$Li. The excited $^{133}$Sb will be populated by transfer of a triton into $^{132}$Sn, followed by the emission of an $\\alpha$-particle (detected in T-REX) and 2 neutrons. The aim of the experiment is to locate states arising from the coupling of the valence proton of $^{133}$Sb to the collective low-lying phonon excitations of $^{132}$Sn (in particular the 3$^−$). According to calculations in the weak-coupling approach, these states lie in the 4$\\, - \\,$5 MeV excitation energy region and in the spin interval 1/2$\\, - \\,$ 19/2, i.e., in the region populated by the cluster transfer reaction. The results will be used to perform advanced tests of different types of nuclear interactions, usually employed in the description of particle-phonon coupled excitations. States arising from couplings of the proton with simpler core excitations, involving few nucleons...

  3. Li(+) Local Structure in Li-Tetraglyme Solvate Ionic Liquid Revealed by Neutron Total Scattering Experiments with the (6/7)Li Isotopic Substitution Technique.

    Science.gov (United States)

    Saito, Soshi; Watanabe, Hikari; Hayashi, Yutaka; Matsugami, Masaru; Tsuzuki, Seiji; Seki, Shiro; Canongia Lopes, José N; Atkin, Rob; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi; Kameda, Yasuo; Umebayashi, Yasuhiro

    2016-07-21

    Equimolar mixtures of lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and tetraglyme (G4: CH3O-(CH2CH2O)4-CH3) yield the solvate (or chelate) ionic liquid [Li(G4)][TFSA], which is a homogeneous transparent solution at room temperature. Solvate ionic liquids (SILs) are currently attracting increasing research interest, especially as new electrolytes for Li-sulfur batteries. Here, we performed neutron total scattering experiments with (6/7)Li isotopic substitution to reveal the Li(+) solvation/local structure in [Li(G4)][TFSA] SILs. The experimental interference function and radial distribution function around Li(+) agree well with predictions from ab initio calculations and MD simulations. The model solvation/local structure was optimized with nonlinear least-squares analysis to yield structural parameters. The refined Li(+) solvation/local structure in the [Li(G4)][TFSA] SIL shows that lithium cations are not coordinated to all five oxygen atoms of the G4 molecule (deficient five-coordination) but only to four of them (actual four-coordination). The solvate cation is thus considerably distorted, which can be ascribed to the limited phase space of the ethylene oxide chain and competition for coordination sites from the TFSA anion. PMID:27388117

  4. Formation of ultracold (7)Li(85)Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy.

    Science.gov (United States)

    Altaf, Adeel; Dutta, Sourav; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S

    2015-03-21

    We report the formation of ultracold (7)Li(85)Rb molecules in the a(3)Σ(+) electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ∼62 cm(-1) below the (7)Li 2s (2)S1/2 + (85)Rb 5p (2)P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a(3)Σ(+) state and excited electronic 3(3)Π and 4(3)Σ(+) states and identify a(3)Σ(+) (v″ = 7-13), 3(3)Π (vΠ' = 0-10), and 4(3)Σ(+) (vΣ' = 0-5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state. PMID:25796252

  5. [sup 7]Li-NMR determination of stability constants as a function of temperature for lithium-crown ether complexes in a molten salt mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Gerhard, A. (Univ. of Utah, Salt Lake City, UT (United States) Univ. of Witten/Herdecke (Germany)); Cobranchi, D.P.; Garland, B.A.; Highley, A.M.; Huang, Y.H.; Konya, G.; Eyring, E.M. (Univ. of Utah, Salt Lake City, UT (United States)); Zahl, A.; Eldik, R. van (Univ. of Witten/Herdecke (Germany)); Petrucci, S. (Polytechnic Univ., Farmingdale, NY (United States))

    1994-08-11

    The stability constants of several crown ethers with lithium ion were determined by [sup 7]Li-NMR measurements. A room temperature, basic molten salt of the composition of 55/45 mol % 1-methyl-3-ethyl-imidazolium chloride to aluminum (III) chloride was used as solvent. On the basis of a 1:1 complex formation the following order was found for the stability constants of the investigated crown ethers: 18-crown-6 < 12-crown-4 < benzo-15-crown-5 < 15-crown-5. A temperature dependence study for 12-crown-4, benzo-15-crown-5, and 15-crown-5 was undertaken for the range 5-84[degree]C. Values of [Delta]H and [Delta]S were calculated. At 5.5[degree]C the splitting of the single, fast exchange peak into two separate signals was observed for benzo-15-crown-5, providing further evidence for the formation of the 1:1 complex. 34 refs., 4 figs., 5 tabs.

  6. A microdosimetric study of {sup 10}B(n,{alpha}){sup 7}Li and {sup 157}Gd(n,{gamma}) reactions for neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.K.C.; Sutton, M.; Evans, T.M. [Georgia Inst. of Tech., Atlanta, GA (United States); Laster, B.H. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    1999-01-01

    This paper presents the microdosimetric analysis for the most interesting cell survival experiment recently performed at the Brookhaven National Laboratory (BNL). In this experiment, the cells were first treated with a gadolinium (Gd) labeled tumor-seeking boronated porphyrin (Gd-BOPP) or with BOPP alone, and then irradiated with thermal neutrons. The resulting cell-survival curves indicate that the {sup 157}Gd(n,{gamma}) reactions are very effective in cell killing. The death of a cell treated with Gd-BOPP was attributed to either the {sup 10}B(n,{alpha}){sup 7}Li reactions or the {sup 157}Gd(n,{gamma}) reactions (or both). However, the quantitative relationship between the two types of reaction and the cell-survival fraction was not clear. This paper presents the microdosimetric analysis for the BNL experiment based on the measured experimental parameters, and the results clearly suggest a quantitative relationship between the two types of reaction and the cell survival fraction. The results also suggest new research in gadolinium neutron capture therapy (GdNCT) which may lead to a more practical modality than the boron neutron capture therapy (BNCT) for treating cancers.

  7. Ab initio calculations on the spectroscopic constants,vibrational levels and classical turning points for the 21Πu state of dimer 7Li2

    Institute of Scientific and Technical Information of China (English)

    Liu Yu-Fang; Sun Jin-Feng; Ma Heng; Zhu Zun-Lue

    2007-01-01

    The accurate dissociation energy and harmonic frequency for the highly excited 21 Πu state of dimer 7Li2 have been calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space.The calculated results are in excellent agreement with experimental measurements.The potential energy curves at numerous basis sets for this state are obtained over a wide internuclear separation range from about 2.4ao to 37.0ao.And the conclusion is gained that the basis set 6-311++G(d,p) is a most suitable one.The calculated spectroscopic constants De,Re,ωe,ωeχe,αe and Be at 6-311++G(d,p) are 0.9670 eV,0.3125 nm,238.6 cm-1,1.3705cm-1,0.0039 cm-1 and 0.4921 cm-1.respectively.The vibrational levels are calculated by solving the radial Schr(o)dinger equation of nuclear motion.A total of 53 vibrational levels are found and reported for the first time.The classical turning points have been computed.Comparing with the measurements,in which only the first nine vibrational levels have been obtained so far,the present calculations are very encouraging.A careful comparison of the present results of the parameters De and ωe with those obtained from previous theories clearly shows that the present calculations are much closer to the measurements than previous theoretical results,thus representing an improvement on the accuracy of the ab initio calculations of the potentials for this state.

  8. Optimization of the proton chopper for {sup 7}Li(p,n) neutron spectrometry using a {sup 3}He ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Matysiak, W., E-mail: matysiw@mcmaster.c [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, L8S 4K1 (Canada); Chettle, D.R.; Prestwich, W.V.; Byun, S.H. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON, L8S 4K1 (Canada)

    2011-02-11

    Thick target {sup 7}Li(p,n) neutron spectra were measured with a {sup 3}He ion chamber in the proton energy region between 1.95 and 2.3 MeV using the McMaster pulsed accelerator neutron source. The pulsed neutron beam was produced by an electrostatic proton chopper to reject the slow neutron detection events, which seriously limit the fast neutron counting rate of the {sup 3}He ion chamber. To collect both arrival time and energy information of {sup 3}He detection events, a custom two-dimensional time-energy analyzer was built using a time scaler and a successive approximation peak-sensing ADC. At each proton energy, the optimum chopper operation was determined by taking into account the two competing requirements: high fast-to-slow neutron ratio and reasonable fast neutron counting rate. The proton pulse widths used were 10 {mu}s for 1.95 and 2.1 MeV proton energies, whereas a shorter, 5 {mu}s proton pulse was used for 2.3 MeV acquisition. The raw data were analyzed using three spectral unfolding methods: a simple division by detection efficiency, an iterative algorithm, and a regularized constrained inversion method. The three methods gave consistent neutron fluence spectra within 20% above 30 keV. Thanks to the enhanced fast-to-slow neutron ratio of the pulsed beam, the full detector response function could be employed in unfolding, which led to an extension of the dynamic energy range as well as a better stability of unfolding process in the low energy region.

  9. The cross-section data from neutron activation experiments on niobium in the NPI p-7Li quasi-monoenergetic neutron field

    Science.gov (United States)

    Honusek, M.; Bém, P.; Fischer, U.; Götz, M.; Novák, J.; Simakov, S. P.; Šimečková, E.

    2010-10-01

    The reaction of protons on 7Li target produces the high-energy quasi- monoenergetic neutron spectrum with the tail to lower energies. Proton energies of 19.8, 25.1, 27.6, 30.1, 32.6, 35.0 and 37.4 MeV were used to obtain quasi-monoenergetic neutrons with energies of 18, 21.6, 24.8, 27.6, 30.3, 32.9 and 35.6 MeV, respectively. Nb cross-section data for neutron energies higher than 22.5 MeV do not exist in the literature. Nb is the important material for fusion applications (IFMIF) as well. The variable-energy proton beam of NPI cyclotron is utilized for the production of neutron field using thin lithium target. The carbon backing serves as the beam stopper. The system permits to produce neutron flux density about 109 n/cm2/s in peak at 30 MeV neutron energy. The niobium foils of 15 mm in diameter and approx. 0.75 g weight were activated. The nuclear spectroscopy methods with HPGe detector technique were used to obtain the activities of produced isotopes. The large set of neutron energies used in the experiment allows us to make the complex study of the cross-section values. The reactions (n,2n), (n,3n), (n,4n), (n,He3), (n,α) and (n,2nα) are studied. The cross-sections data of the (n,4n) and (n,2nα) are obtained for the first time. The cross-sections of (n,2n) and (n,α) reactions for higher neutron energies are strongly influenced by low energy tail of neutron spectra. This effect is discussed. The results are compared with the EAF-2007 library.

  10. Analysis of the {sup 11}B({sup 7}Li, {sup 7}Be){sup 11}Be reaction at 57 MeV in a microscopic approach

    Energy Technology Data Exchange (ETDEWEB)

    Cappuzzello, F. E-mail: cappuzzello@lns.infn.it; Lenske, H.; Cunsolo, A.; Beaumel, D.; Fortier, S.; Foti, A.; Lazzaro, A.; Nociforo, C.; Orrigo, S.E.A.; Winfield, J.S

    2004-07-12

    The {sup 11}B({sup 7}Li, {sup 7}Be){sup 11}Be charge exchange reaction has been studied at an incident energy of 57 MeV. Spectra were measured at forward angles, {theta}{sub cm}{<=}35 degrees. The good energy resolution ({approx}50 keV) allowed the identification of transitions both to the {sup 7}Be (3/2{sup -}, gs) and {sup 7}Be(1/2{sup -}, 429 keV) exit channels and hence the direct measurement of the ratio of the respective cross sections and angular distributions. Besides the bound ground and first excited state of {sup 11}Be several low lying excitations just above the neutron threshold are observed. A structure seen at E{sup *}=9.4 MeV with FWHM {approx}7 MeV is compatible with the spin dipole resonance (SDR). The data are analysed in a many-body approach. For the projectile transitions shell model results are used. In order to account properly for the special features of the weakly bound {sup 11}Be system the target transitions are described microscopically by Hartree-Fock-Bogoliubov (HFB) and quasi-particle random phase approximation (QRPA) theory. The HFB ground state densities and the QRPA transition densities, respectively, are used in folding calculations for the optical potentials and transition form factors. Spectra and {beta}-decay transitions strengths are reasonably well described. The measured cross section are well reproduced by one-step direct charge exchange distorted wave born approximation (DWBA) calculations. A dominance of unnatural parity transitions is found. This is explained in terms of the spin transfer behaviour of the nucleon-nucleon isovector interaction at low bombarding energy.

  11. Ab initio calculation of accurate dissociation energy,potential energy curve and dipole moment function for the A1∑+ state 7LiH molecule

    Institute of Scientific and Technical Information of China (English)

    Shi De-Heng; Liu Yu-Fang; Sun Jin-Feng; Yang Xiang-Dong; Zhu Zun-Lue

    2006-01-01

    The reasonable dissociation limit of the A1∑+ state 7LiH molecule is obtained. The accurate dissociation energy and the equilibrium geometry of this state are calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space for the first time. The whole potential energy curve and the dipole moment function for the A1∑+ state are calculated over a wide internuclear separation range from about 0.1 to 1.4 nm. The calculated equilibrium geometry and dissociation energy of this potential energy curve are of Re=0.2487 nm and De=1.064 eV,respectively. The unusual negative values of the anharmonicity constant and the vibration-rotational coupling constant are of wexe=-4.7158cm-1 and αe=-0.08649cm-1, respectively. The vertical excitation energy from the ground to the A1∑+ state is calculated and the value is of 3.613eV at 0.15875nm (the equilibrium position of the ground state).The highly anomalous shape of this potential energy curve, which is exceptionally flat over a wide radial range around the equilibrium position, is discussed in detail. The harmonic frequency value of 502.47cm-1 about this state is approximately estimated. Careful comparison of the theoretical determinations with those obtained by previous theories about the A1∑+ state dissociation energy clearly shows that the present calculations are much closer to the experiments than previous theories, thus represents an improvement.

  12. The cross-section data from neutron activation experiments on niobium in the NPI p-7Li quasi-monoenergetic neutron field

    Directory of Open Access Journals (Sweden)

    Simakov S.P.

    2010-10-01

    Full Text Available The reaction of protons on 7Li target produces the high-energy quasi- monoenergetic neutron spectrum with the tail to lower energies. Proton energies of 19.8, 25.1, 27.6, 30.1, 32.6, 35.0 and 37.4 MeV were used to obtain quasi-monoenergetic neutrons with energies of 18, 21.6, 24.8, 27.6, 30.3, 32.9 and 35.6 MeV, respectively. Nb cross-section data for neutron energies higher than 22.5 MeV do not exist in the literature. Nb is the important material for fusion applications (IFMIF as well. The variable-energy proton beam of NPI cyclotron is utilized for the production of neutron field using thin lithium target. The carbon backing serves as the beam stopper. The system permits to produce neutron flux density about 109  n/cm2/s in peak at 30 MeV neutron energy. The niobium foils of 15 mm in diameter and approx. 0.75 g weight were activated. The nuclear spectroscopy methods with HPGe detector technique were used to obtain the activities of produced isotopes. The large set of neutron energies used in the experiment allows us to make the complex study of the cross-section values. The reactions (n,2n, (n,3n, (n,4n, (n,He3, (n,α and (n,2nα are studied. The cross-sections data of the (n,4n and (n,2nα are obtained for the first time. The cross-sections of (n,2n and (n,α reactions for higher neutron energies are strongly influenced by low energy tail of neutron spectra. This effect is discussed. The results are compared with the EAF-2007 library.

  13. Contribution to the study of the influence of the Pauli principle and of its modelization in nuclear reactions between heavy ions: application to the reaction 7Li

    International Nuclear Information System (INIS)

    A simple model based on the Hackenbroich approach of the R.G.M. theory which simulates the Pauli principle among clusters has been derived in the following way. The exact antisymmetrization between the nucleon belonging to a given cluster has been kept. The contribution of the exchange terms between two different clusters, which give rise to non-local potentials, has been simulated by the matrix elements of an effective local, l-dependent, energy-independent nucleon-nucleon potential. With these potentials (added to the regular n-n interaction) the low energy levels of 8Be and 7Li as well as the phase shifts l=0,2,4 for α-α scattering and l=0 to 4 for α-n and α-t scattering for energies below 10MeV (c.m.) have been calculated. Good agreement between exact antisymmetrized and modelized calculations is achieved. With this model elastic and inelastic scattering of α on 7Li have been calculated. The 7Li has been described in terms of α,t clusters. The coupling with the 8Be + t channel has been taken into account. A good agreement between experimental data and modelized theoretical calculations is achieved when the projectile energy is less than 5MeV (lab. system). It appears that the coupling with the 8Be + t channel is not negligible even below this channel threshold

  14. The 10B(n,α)7Li reaction in PWR coolants: calculations of the effect on coolant pH and on decreases in 10B isotopic fractions

    International Nuclear Information System (INIS)

    Boron is used as a chemical shim in PWRs for reactivity control and is added in the form of boric acid to the primary coolant. The 10B(n,α)7Li reaction leads to a continuous increase in 7Li in the primary coolant and to a continuous decrease in 10B the isotope of boron responsible for control of reactivity. The rate of increase in coolant pH due to 7Li production is calculated for the Sizewell 'B' PWR to enable judgements to be made on the frequency of sampling and removal of lithium required to maintain the pH of the primary coolant within the desired limits. Calculations are contrasted for the cases of natural boron and 100% 10B chemical shims, for both a normal cycle and an extended 18 month cycle. Calculations of 10B depletion over 30 years of operation as a function of the quantity of boron discharged to waste are also presented. 10B isotopic fractions are calculated for the reactor coolant (RC), boric acid tanks (BATs) and refuelling water storage tank (RWST) assuming rapid mixing of BAT and RC boron for tritium control and other reasons. Such predictions enable assessments of the reactor physics implications of 10B consumption to be made. (author)

  15. Experimental determination of sensitivity of DN-A-1 dosimeter and 6LiJ(Eu) scintillation detector in sphere polyethylene moderators in the 30 keV neutron energy range

    International Nuclear Information System (INIS)

    DH-A-1 dosimeter and 6LiJ(Eu) detector, located in the center of polyethylene spheres with various diameters, were calibrated by means of neutrons with the energy of about 30 keV. The data on the detectors responses enable one to determine the shape of responses as a function of neutron energy more definitely at the energy range from some keV to some tens of keV. For DN-A-1 dosimeter response at neutrons and at neutrons in the energy range of about 30 keV the agreement is better than the uncertainties of measurements (about 20%)

  16. 中子探测用含6Li玻璃闪烁材料最新进展%Development of Containing 6Li Glass Scintillators for Neutron Detection

    Institute of Scientific and Technical Information of China (English)

    陈艳平; 罗德礼

    2012-01-01

    Since the development of first generation glass scintillators for neutron detection in the 1950s, glass scintillators have played an increasingly unsubstitutional role in the fields of nuclear physics, high energy physics, industry detection (neutron spectrum measurement, neutron radiography, a, p, and γ-ray detection in extreme environments). Most researches were concentrated on containing 6Li, 10B silicate, phosphate, fluoro-oxide glass doped with lanthanide ions (Ce3+, Tb3+, Pr3+, etc.). This paper described performance characteristic, development history and luminescence mechanism of glass scintillators, then focused on studies about preparation methods, optical properties, neutron detection efficiency and luminescence delay time measurement of containing 6Li silicate glass, containing 6Li phosphate glasses, 6Li fluoxygen glasses and other glass scintillators, and pointed out future development trends and application fields of glass scintillators.%自上世纪50年代第一代玻璃闪烁材料开发以来,玻璃闪烁材料在核物理、高能物理、工业探测(中子能谱测量、中子射线照相术及极端环境下α、β与γ射线的探测等)等领域发挥着越来越难以替代的作用.中子探测用玻璃闪烁材料的研究集中于镧系离子(Ce3+、Tb3+、Pr3+等)掺杂含6Li、10B等中子吸收截面较大核素的硅酸盐、磷酸盐、铝酸盐上.本文由中子探测用玻璃闪烁材料的性能特点、发展历程与发光机理出发,重点关注了含6Li硅酸盐玻璃、磷酸盐玻璃、氟氧玻璃及其它玻璃闪烁材料的制备方法、光学性能、荧光衰减时间及中子探测效率等性能研究,并对玻璃闪烁材料的发展趋势及未来应用方向作出了展望.

  17. Fast Li ion dynamics in the solid electrolyte Li7 P3 S11 as probed by (6,7) Li NMR spin-lattice relaxation.

    Science.gov (United States)

    Wohlmuth, Dominik; Epp, Viktor; Wilkening, Martin

    2015-08-24

    The development of safe and long-lasting all-solid-state batteries with high energy density requires a thorough characterization of ion dynamics in solid electrolytes. Commonly, conductivity spectroscopy is used to study ion transport; much less frequently, however, atomic-scale methods such as nuclear magnetic resonance (NMR) are employed. Here, we studied long-range as well as short-range Li ion dynamics in the glass-ceramic Li7 P3 S11 . Li(+) diffusivity was probed by using a combination of different NMR techniques; the results are compared with those obtained from electrical conductivity measurements. Our NMR relaxometry data clearly reveal a very high Li(+) diffusivity, which is reflected in a so-called diffusion-induced (6) Li NMR spin-lattice relaxation peak showing up at temperatures as low as 313 K. At this temperature, the mean residence time between two successful Li jumps is in the order of 3×10(8) s(-1) , which corresponds to a Li(+) ion conductivity in the order of 10(-4) to 10(-3) S cm(-1) . Such a value is in perfect agreement with expectations for the crystalline but metastable glass ceramic Li7 P3 S11 . In contrast to conductivity measurements, NMR analysis reveals a range of activation energies with values ranging from 0.17 to 0.26 eV, characterizing Li diffusivity in the bulk. In our case, through-going Li ion transport, when probed by using macroscopic conductivity spectroscopy, however, seems to be influenced by blocking grain boundaries including, for example, amorphous regions surrounding the Li7 P3 S11 crystallites. As a result of this, long-range ion transport as seen by impedance spectroscopy is governed by an activation energy of approximately 0.38 eV. The findings emphasize how surface and grain boundary effects can drastically affect long-range ionic conduction. If we are to succeed in solid-state battery technology, such effects have to be brought under control by, for example, sophisticated densification or through the preparation

  18. 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.

  19. Invariance par renversement du temps : nouvelles mesures de polarisation dans la réaction 9Be(3He, p)11B

    OpenAIRE

    Pouliot, J.; Bricault, P.; Dufour, J. G.; Potvin, L.; Rioux, C.; R. Roy; Slobodrian, R.J.

    1984-01-01

    La polarisation des protons dans la réaction 9Be(3He, p)11B à 14 MeV d'énergie incidente a été mesurée à l'aide d'un nouveau montage expérimental constitué de polarimètres à analyseurs de carbone ou de silicium, en trois versions différentes. Les résultats confirment les mesures précédentes qui montraient des différences significatives entre la polarisation dans la réaction 9Be(3He, p)11B et le pouvoir d'analyse dans la réaction inverse 11B(p, 3He)9Be, impliquant, par l'égalité non vérifiée d...

  20. Local environments and lithium adsorption on the iron oxyhydroxides lepidocrocite (gamma-FeOOH) and goethite (alpha-FeOOH): A 2H-2 and 7Li solid-state MAS NMR study

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Grey, Clare P.; Paik, Jonkim

    2008-01-01

    2H and 7LiMAS NMR spectroscopy techniques were applied to study the local surface and bulk environments of iron oxyhydroxide lepiclocrocite (gamma-FeOOH). 2H variable-temperature (VT) MAS NMR experiments were performed, showing the presence of short-range, strong antiferromagnetic correlations......) on the concentrations of Li+ inner- and outer-sphere complexes was then explored, the concentration of the inner sphere complex increasing rapidly above the point of zero charge and with decreasing RH. Possible local environments of the adsorbed Li+ were identified by comparison with other layer-structured iron oxides...

  1. 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.

  2. Quasi-elastic Scattering of a Secondary 6He Beam on a 9Be Target at 25MeV/Nucleon

    Institute of Scientific and Technical Information of China (English)

    陈陶; 叶沿林; 李智焕; 江栋兴; 华辉; 李湘庆; 王全进; 葛榆成; 庞丹阳; 狄振宇; 靳根明; 肖国青; 郭忠言; 肖志刚; 王宏伟; 张保国; 吴和宇; 李家兴; 孙志宇; 詹文龙

    2002-01-01

    The quasi-elastic scattering of a secondary 6He beam (25 MeV/n) on a 9Be target has been measured for the firsttime with the application of a sophisticated tracking detector system. The angular distribution is reported. Aphenomenological optical potential is obtained by fitting the experimental data, which encourages more accurateexperimental measurements.

  3. Application of the Frahn scaling formula to the analysis of the excitation of 1- states in 40Ca by 9Be scattering

    International Nuclear Information System (INIS)

    The simple scaling formula derived by Frahn for the heavy-ion inelastic cross section of excitation of 1- states in even-even nuclei has been applied to the excitation of the 1- states in 40Ca at 5.91 and 6.94 MeV by 45 and 60 MeV 9Be projectiles

  4. Synthesis and crystal structure of a new hexagonal perovskite 7H-Ba7Li1.75Mn3.5O15.75 with Mn(4+)/Mn(5+) charge distribution.

    Science.gov (United States)

    Tarakina, N V; Tyutyunnik, A P; Bazuev, G V; Vasiliev, A D; Vasilev, A D; Gould, C; Nikolaenko, I V; Berger, I F

    2015-11-14

    Ba7Li1.75Mn3.5O15.75 is a new hexagonal perovskite whose crystal structure has elements typical for the layered hexagonal perovskites and quasi-one-dimensional oxides, hence representing a new polytype. It has been synthesized via a solid-state microwave route. The crystal structure was solved using a combination of X-ray and neutron diffraction data, which show that Ba7Li1.75Mn3.5O15.75 crystallizes in a hexagonal unit cell with parameters a = 5.66274(2) Å and c = 16.7467(1) Å (V = 465.063(4) Å(3)), with one formula unit, and can be described as columns of face-shared octahedra occupied by Mn(4+) and Li(+) cations and vacancies along the c axis separated in the ab plane by barium atoms. Every sixth layer, the coordination of Mn(5+) and Li(+) changes to tetrahedral. Additional local ordering of manganese and lithium atoms among cationic sites leading to the formation of a rhombohedral supercell has been observed by scanning transmission electron microscopy. PMID:26442571

  5. Study of the reduction in detection limits of track detectors used for {sup 10}B(n,α){sup 7}Li reaction rate measure through annealing and chemical etching experiments; Estudo da reducao nos limites de deteccao de detectores de tracos utilizados na medida de taxa de reacao {sup 10}B(n, α){sup 7}Li atraves de experimentos de annealing e ataque quimico

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Herminiane L.; Smilgys, Barbara; Guedes, Sandro, E-mail: hluizav@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Castro, Vinicius A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-08-15

    The Boron Neutron Capture Therapy (BNCT) is an experimental radiotherapy for cancer treatment. It is based on {sup 10}B(n, α){sup 7}Li reaction, which can be measured by track detectors capable of recording events that strike them. With this recording, it is possible to determine the number of alpha particles and recoiling Lithium-7 nucleus, reaction products, and from this information, which amount of radiation dose a patient is exposed to. In this work, PADC detectors were characterized, irradiated at the IEA-R1 IPEN/CNEN reactor to assess the contribution of the{sup 10}B(n, α){sup 7}Li reaction and protons from fast neutron scattering with the elements that compounds the tissue. With the aim of reducing the proton background, the detectors were subjected to heating experiments at 80°C for periods in the range 0-100 hours. This was done in order to restore partially modified structure of the detector, causing a reduction in the size and density of tracks. This effect is known as annealing. For the visualization of tracks at microscope, detectors were made three chemical attacks with sodium hydroxide (NaOH) for 30, 60 and 90 minutes at 70°C. It was observed a reduction in the track density achieving a plateau heating time of 50 hours. For detectors that have not undergone annealing and were etched with another etchant, PEW solution, a reduction of 87% in track density was obtained. (author)

  6. Drivers of foraminiferal and bulk-sedimentary 10Be/9Be ratios in a marine sediment record offshore of sub-tropical Australia

    Science.gov (United States)

    Davies, M. H.; Abrajevitch, A.; Srncik, M.; Fifield, L. K.; De Deckker, P.; Heslop, D.; Roberts, A. P.

    2013-12-01

    Meteoric 10Be (half-life of ~1.5 My) is produced in the atmosphere via cosmic ray spallation of 16O, following which it is quickly transported to Earth's surface by precipitation. This process concentrates 10Be in the ocean, where it is thought to remain with a residence time of ~500-1000 years prior to export to the marine sedimentary record largely associated with sorption to the surface of settling clay particles. The bulk beryllium isotopic composition of marine clays hence reflects the convoluted factors of 10Be production and varying scavenging efficiency/terrigenous input. However, measurements of meteoric 10Be/9Be incorporated in the calcium carbonate tests of foraminifera (and hence presumably isolated from the dilution effects of sediment-bound terrigenous 9Be) may have the potential to provide useful chronological control for marine sediment records. Here we present 10Be/9Be results from a ~42 m-long sediment core collected off the NW coast of Australia (MD00-2361: 113°28.63‧E, 22°04.92‧S, 1805 m water depth). Measurements of δ18O on Globigerinoides ruber, supported by magnetostratigraphy, indicate that the record extends back >1.2 Ma. This independent chronology, in conjunction with excellent carbonate preservation at this site, allows preliminary evaluation of foraminiferal 10Be as a chronometer. We also evaluate the relationship between sedimentary 10Be/9Be ratios, regional surface ocean conditions as inferred from the δ18O stratigraphy and low-resolution Globigerinoides ruber Mg/Ca ratios, as well as large-scale changes in regional fluvial input as reconstructed from high-resolution XRF scanning profiles.

  7. Isotopic distributions of the sup 1 sup 8 N fragmentation products in coincidence with neutrons on targets sup 1 sup 9 sup 7 Au and sup 9 Be

    CERN Document Server

    Li Xiang Qing; Ye Yan Lin; Hua Hui; Chen Tao; Li Zhi Huan; Ge Yuch Eng; Wang Quan Jin; Wu He Yu; Jin Ge; Duan Li Min; Xiao Zhi Gang; Wang Hong Wei; Li Zhu Yu; Wang Su Fang

    2002-01-01

    The authors present the experimental isotopic distributions of the sup 1 sup 8 N projectile fragmentation products Li, Be, B and C in coincidence with neutrons, as well as the inclusive ones on sup 1 sup 9 sup 7 Au and sup 9 Be targets. In the framework of the abrasion-ablation model, these distributions are calculated for various nucleon density distributions of the projectile. The comparison with experimental isotopic distributions of the projectile-like fragments in coincidence with neutrons shows that the information on the nucleon density distribution of the sup 1 sup 8 N projectile can be extracted

  8. Authigenic 10Be/9Be ratios and 10Be-fluxes (230Thxs-normalized) in central Baffin Bay sediments during the last glacial cycle: Paleoenvironmental implications

    Science.gov (United States)

    Simon, Quentin; Thouveny, Nicolas; Bourlès, Didier L.; Nuttin, Laurence; Hillaire-Marcel, Claude; St-Onge, Guillaume

    2016-05-01

    Authigenic 10Be/9Be ratios and 10Be-fluxes reconstructed using the 230Thxs normalization, proxies of the cosmogenic radionuclide 10Be production rate in the atmosphere, have been measured in a sedimentary core from Baffin Bay (North Atlantic) spanning the last 136 ka BP. The normalization applied on the exchangeable (authigenic) 10Be concentrations using the authigenic 9Be isotope and 230Thxs methods yield equivalent results strongly correlated with sedimentological parameters (grain-size and mineralogy). Lower authigenic beryllium (Be) concentrations and 10Be/9Be ratios are associated with coarse-grained carbonate-rich layers, while higher authigenic Be values are related to fine-grained felspar-rich sediments. This variability is due to: i) sediment composition control over beryllium-scavenging efficiency and, ii) glacial history that contributed to modify the 10Be concentration in Baffin Bay by input and boundary scavenging condition changes. Most paleo-denudation rates inferred from the 10Be/9Be ratio vary weakly around 220 ± 76 tons.km-2.yr-1 (0.09 ± 0.03 mm.yr-1) corresponding to relatively steady weathering fluxes over the last glacial cycle except for six brief intervals characterized by sharp increases of the denudation rate. These intervals are related to ice-surging episodes coeval with Heinrich events and the last deglaciation period. An average freshwater flux of 180.6 km3.yr-1 (0.006 Sv), consistent with recent models, has been calculated in order to sustain glacially-derived 10Be inputs into Baffin Bay. It is concluded that in such environments, the authigenic 10Be measured mainly depends on climatic effects related to the glacial dynamics, which masks the 10Be production variation modulated by geomagnetic field changes. Altogether, these results challenge the simple interpretation of 10Be-concentration variation as a proxy of Interglacial/Glacial (interstadial/stadial) cycles in Arctic and sub-Arctic regions. They rather suggest the effect of

  9. Spin and parity determinations of excited 15N based on polarized and unpolarized 12C(7Li, α)15N reaction data at E lab = 34 MeV

    International Nuclear Information System (INIS)

    From an experiment conducted at the Florida State University Accelerator Laboratory with a 34 MeV polarized 7Li beam bombarding a 12C target, we have obtained angular distributions and analyzing powers for states of 15N up to 20 MeV in excitation energy. This study not only offers the possibility to assign spin and parity to several states in 15N, but also serves to obtain nuclear potential parameters used in Distorted Wave Born (DWBA) and Coupled Channel Born (CCBA) Approximations to generate theoretical angular distributions and vector analyzing powers that give the best description of the experimental data. Under the assumption that the reaction mechanism is a three nucleon transfer, the determination of shell model nucleonic configurations and spectroscopic factors is possible for the 15N states studied

  10. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors. PMID:24387907

  11. Electrochemical performance and 7Li NMR studies on an inverse spinel LiNi 1/3Co 1/3Mn 1/3VO 4 for Li-ion batteries

    Science.gov (United States)

    Fey, George Ting-Kuo; Muralidharan, P.; Cho, Yung-Da; Chang, Pai-Ching; Kao, Hsien-Ming

    A new inverse spinel LiNi 1/3Co 1/3Mn 1/3VO 4 cathode material was synthesized through a citric acid assisted polyethylene glycol (CA:PEG; 3:1, 3:0.5 and 3:0) polymeric method, followed by calcination at 723 K for 5 h in air. The synthesized compound was characterized by TG/DTGA, XRD, FTIR, TEM, and 7Li NMR techniques. TG/DTGA curves showed that the formation of LiNi 1/3Co 1/3Mn 1/3VO 4 occurred between 523 and 673 K and the phase pure crystalline formed at 723 K, as also confirmed by XRD analysis which showed that the crystalline phase peaks formed when heated at 723 K for 5 h in air. TEM images revealed that nanosized particles ranged ∼170-190 nm. FTIR spectra showed that all organic residues were removed and LiNi 1/3Co 1/3Mn 1/3VO 4 formed. The 7Li MAS NMR spectrum of the LiNi 1/3Co 1/3Mn 1/3VO 4 sample revealed that the paramagnetic effect is small and small side band manifolds were observed. The galvanostatic cycling study suggests that the cycle stability and capacity retention were enhanced for LiNi 1/3Co 1/3Mn 1/3VO 4 prepared with a CA:PEG molar ratio of 3:1 when it was cycled between 2.8 and 4.9 V (versus Li) at a 0.15 C rate. The electrochemical impedance behavior suggested that a passive layer was formed on the surface of the cathode materials during continuous cycling.

  12. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.

  13. Authigenic 10Be/9Be Ratio Signatures of the Cosmogenic Nuclide Production Linked to Geomagnetic Dipole Moment Variation During and Since the Brunhes/Matuyama Boundary

    Science.gov (United States)

    Simon, Q.; Thouveny, N.; Bourles, D. L.; Ménabréaz, L.; Valet, J. P.; Valery, G.; Choy, S.

    2015-12-01

    The atmospheric production rate of cosmogenic nuclides is linked to the geomagnetic dipole moment (GDM) by a non-linear inverse relationship. Large amplitude GDM variations associated with reversals and excursions can potentially be reconstructed using time variation of the cosmogenic beryllium-10 (10Be) production recorded in ocean sediments. Downcore profiles of authigenic 10Be/9Be ratios (proxy of atmospheric 10Be production) in oceanic cores provide independent and additional records of the evolution of the geomagnetic intensity and complete previous information derived from relative paleointensity (RPI). Here are presented new authigenic 10Be/9Be results obtained from cores MD05-2920 and from the top of core MD05-2930 collected in the West Equatorial Pacific Ocean. Completing data of Ménabréaz et al. (2012, 2014), these results provide the first continuous 10Be production rate sedimentary record covering the last 800 ka. Along these cores, authigenic 10Be/9Be ratio peaks are recorded - within methodological errors - at the stratigraphic level of RPI lows. High-resolution chronologies (δ18O-derived) lead to interpret these peaks as successive global 10Be overproduction events triggered by geomagnetic dipole lows present in the PISO-1500 and Sint-2000 stacks. The largest amplitude 10Be production enhancement is synchronous to the very large decrease of the dipole field associated with the last polarity reversal (772 ka). It is consistent in shape and duration with the peak recorded in core MD90-0961 from the Maldive area (Indian Ocean) (Valet et al. 2014). Two significant 10Be production enhancements are coeval with the Laschamp (41 ka) and Icelandic basin (190 ka) excursions, while 10Be production peaks of lower amplitude correlate to other recognized excursions such as the Blake (120 ka), Pringle-Falls (215 ka), Portuguese Margin (290 ka), Big Lost (540 ka) among others. This study provides new data on the amplitude and timing of dipole field variations

  14. 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....

  15. Reaction Mechanisms in the Li3AlH6/LiBH4 and Al/LiBH4 Systems for Reversible Hydrogen Storage. Part 2: Solid-State NMR Studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Joon; Lu, Jun; Sohn, Hong Yong; Fang, Zhigang Zak; Kim, Chul; Bowman, Robert C.; Hwang, Son-Jong

    2011-09-01

    In Part 1, the promising hydrogen storage properties of the combined systems of Li3AlH6/LiBH4 and Al/LiBH4, exhibiting the favorable formation of AlB2 during dehydrogenation, were presented based on TGA and XRD analyses. The present Part 2 describes the characterization of the intermediate and final products of the dehydrogenation and rehydrogenation of the above systems by multinuclear solid state NMR characterization. This work has also verified that the presence of Al resulted in the re-formation of LiBH4 occurring at a much lower temperature and H2 pressure, under which conditions the dehydrogenation product from LiBH4 alone does not show any degree of rehydrogenation. NMR studies mainly identified various reaction intermediates for LiBH4 dehydrogenation/rehydrogenation reactions. Unlike the XRD studies, the AlB2 formation in particular could not be unambiguously confirmed by NMR. 27Al NMR showed that aluminum was mainly involved in various Li-Al alloy formations. The catalytic role of Al in the LiBH4 hydrogen storage reactivity could be achieved by a reversible cycle of Al + LiH ↔ LiAl + 1/2H2 reaction.

  16. 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.

  17. Study of some quasi-free reactions induced by 58 MeV protons on 9Be, 12C and 14N

    International Nuclear Information System (INIS)

    (p,pd) (p,pt) and (p,p3H) quasi-free scattering have been studied at 58 MeV, together with some quasi-free reactions, on three 1 p shell nuclei: 9Be, 12C and 14N by detecting two outgoing particles. A good energy resolution permitted the observation of several low-lying levels of the residual nuclei. Experimental results have been analyzed in the frame of the distorded wave impulse approximation. If such a model is able to reproduce most of the results and gives clear evidence of the quasi-free process, it is not always possible to obtain good quantitative results. However, informations concerning nuclear structure and reaction mechanism are discussed and some spectroscopic informations extracted

  18. Theoretical model analysis of (d ,x n ) reactions on 9Be and 12C at incident energies up to 50 MeV

    Science.gov (United States)

    Nakayama, Shinsuke; Kouno, Hiroshi; Watanabe, Yukinobu; Iwamoto, Osamu; Ogata, Kazuyuki

    2016-07-01

    Background: In the design of deuteron accelerator neutron sources, accurate nuclear data of deuteron-induced reactions are indispensable over a wide range of incident energy. Reliable model calculations play an important role in completing the necessary nuclear data since currently available experimental data are insufficient. We have been developing a code system dedicated for the deuteron-induced reactions, called deuteron-induced reaction analysis code system (DEURACS). It was applied successfully to (d ,x p ) reactions at 56 and 100 MeV. Purpose: The purpose of the present work is to investigate the applicability of DEURACS to (d ,x n ) reactions on 9Be and 12C for incident energies below 50 MeV and to clarify neutron production mechanism. Methods: Double-differential thick target neutron yields (TTNYs) from deuteron bombardment on thick Be and C targets are analyzed. The TTNYs are derived using the double differential (d ,x n ) cross sections calculated by DEURACS and the stopping power of deuteron in the target. The calculated TTNYs are decomposed into individual components corresponding to elastic breakup, proton stripping, and statistical decay reactions. Results: The calculated TTNYs reproduced the experimental data quantitatively well in the incident energy range up to 50 MeV. From the analysis, it was found that the proton stripping reaction makes the most dominant contribution to neutron production. Conclusions: DEURACS is applicable to (d ,x n ) reactions on 9Be and 12C for incident energies below 50 MeV. Modeling of the stripping reaction is essential to predict neutron production yields accurately in the design of deuteron accelerator neutron sources.

  19. $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

    CERN Document Server

    Fornal, B; Bednarczyk, P; Cieplicka, N; Krolas, W; Maj, A; Leoni, S; Benzoni, G; Blasi, N; Bottoni, S; Bracco, A; Camera, F; Crespi, F; Million, B; Morales, A; Wieland, O; Rusek, K; Lunardi, S; Mengoni, D; Recchia, F; Ur, CA; Valiente-Dobon, J; de France, G; Clement, E; Elseviers, J; Flavigny, F; Huyse, M; Raabe, R; Sambi, S; Van Duppen, P; Sferrazza, M; Simpson, G; Georgiev, G; Sotty, C; Blazhev, A; German, R; Siebeck, B; Seidlitz, M; Reiter, P; Warr, N; Boenig, S; Ilieva, S; Kroell, T; Scheck, M; Thurauf, M; Gernhaeuser, R; Mucher, D; Janssens, R; Carpenter, MP; Zhu, S; Marginean, NM; Balabanski, D; Kowalska, M

    2012-01-01

    $\\gamma$- spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li: Introduction to HIE-ISOLDE studies of n-rich Sb and Tl isotopes with Sn and Hg radioactive beams.

  20. The geomagnetic dipole moment variation between 250 and 800 ka BP reconstructed from the authigenic 10Be/9Be signature in West Equatorial Pacific sediments

    Science.gov (United States)

    Ménabréaz, Lucie; Thouveny, Nicolas; Bourlès, Didier L.; Vidal, Laurence

    2014-01-01

    The authigenic 10Be/9Be ratio, proxy of the cosmogenic radionuclide 10Be production rate in the atmosphere, was measured in sediments deposited in the West Equatorial Pacific (Gulf of Papua; 10°25 S; 146°15 E), in order to reconstruct the geomagnetic dipole moment variations in the 250-800 ka time interval, independently from paleomagnetic methods. The pelagic clayey-carbonate muds continuously deposited between marine isotope stages 8 and 20 were subsampled every 10 cm. The 10Be production rate record reconstructed for the 250-800 ka interval is described and compared over the same time interval with global paleomagnetic stacks (SINT-2000 and PISO-1500). The highlighted cosmogenic 10Be overproductions appear to be triggered by the series of Geomagnetic Dipole Lows (GDL) that have occurred since the Brunhes-Matuyama reversal. Calibration using absolute values of the geomagnetic dipole moment drawn from a paleomagnetic database produces a new record of the dipole moment variations over the 250-800 ka time interval. The timing and amplitude of the GDL succession revealed by such records will contribute to improving knowledge of the geodynamo rhythms and rate of changes at millennial to million year scales.

  1. Isobaric yield ratio difference between the 140 $A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions studied by antisymmetric molecular dynamics model

    CERN Document Server

    Qiao, C Y; Ma, C W; Zhang, Y L; Wang, S S

    2015-01-01

    \\item[Background] The isobaric yield ratio difference (IBD) method is found to be sensitive to the density difference of neutron-rich nucleus induced reaction around the Fermi energy. \\item[Purpose] An investigation is performed to study the IBD results in the transport model. \\item[Methods] The antisymmetric molecular dynamics (AMD) model plus the sequential decay model GEMINI are adopted to simulate the 140$A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions. A relative small coalescence radius R$_c =$ 2.5 fm is used for the phase space at $t =$ 500 fm/c to form the hot fragment. Two limitations on the impact parameter ($b1 = 0 - 2$ fm and $b2 = 0 - 9$ fm) are used to study the effect of central collisions in IBD. \\item[Results] The isobaric yield ratios (IYRs) for the large--$A$ fragments are found to be suppressed in the symmetric reaction. The IBD results for fragments with neutron-excess $I = $ 0 and 1 are obtained. A small difference is found in the IBDs with the $b1$ and $b2$ limitations in the AMD simulated re...

  2. Ab initio calculation on the analytic potential energy functions for the state a3∑u+ and the state b3∏u of spin-aligned trimer 7Li2

    Institute of Scientific and Technical Information of China (English)

    Shi De-Heng; Sun Jin-Feng; Yang Xiang-Dong; Zhu Zun-Lue; Liu Yu-Fang

    2005-01-01

    The energies, equilibrium geometries and harmonic frequencies of the triplet excited states (a3∑u+ and b3∏u) of spin-aligned trimer 7Li2 are firstly calculated by using a symmetry adapted cluster-configuration interaction method.The potential curves for the two excited states have least squares fitted by the Murrell-Sorbie function. The spectroscopic data (Be, αe, ωe, and ωeχe) and the force constants (f2, f3 and f4) are calculated. It is found that the spin-aligned triplet excited state b3∏u is more stable than the ground state X1∑g+, and that the Murrell-Sorbie function form is suitable not only for the ground state but also for the spin-aligned triplet excited states. Comparison between the theoretical determinations of dissociation energies, equilibrium interatomic distances and harmonic frequencies with the agreement between theories and experiments.

  3. Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-CxH(2x+1)OSO3Li (x = 12, 14, 16, 18, and 20)

    International Nuclear Information System (INIS)

    Electrical conductivity (σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C xH(2x+1)OSO3Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C xH(2x+1)OSO3Na and n-C xH(2x+1)OSO3K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (ΔS). For n-C 18H37OSO3Li and n-C 20H41OSO3Li salts, each melting point produced a small ΔSmp value compared with the total entropy change in the solid phases (ΔStr1+ΔStr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18H37OSO3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals

  4. Search for the p1/2- resonance in 7He with the 7Li(d,2He) reaction and measurement of the deuteron electrodisintegration under 180 deg at the S-DALINAC

    International Nuclear Information System (INIS)

    The present work contains two parts, both devoted to the investigation of light nuclei. In the first part of the thesis the structure of the exotic 7He nucleus is studied. The disappearance of the usual magic numbers in extremely neutron-rich nuclei implies a considerable modification in the spin-orbit interaction. Recent experiments yield contradictory results about a possible existence of the p1/2- spin-orbit partner of the 7He ground state with a dominant p3/2- single-particle character. In order to clarify this question a study of the 7Li(d,2He)7He reaction has been performed using a 171 MeV deuteron beam provided by the cyclotron at Kernfysisch Versneller Insituut (KVI) in Groningen. The experiment was carried out in April 2003. The setup at KVI offers a resolution ΔE ∼ 150 keV (FWHM) in the measured spectra, better than the line width of the ground state of 7He. The unbound 2He system was identified by detecting coincidences between two protons with small relative energy. The data were taken over the angular range Θcm=0 -11.3 . A possible resonance at an excitation energy Ex=(1.45-0.5+0.7) MeV with a width Γ=(2.0-1.1+1.0) MeV is suggested by a decomposition of the spectrum using known resonances, the breakup behaviour of 7He and quasifree charge-exchange contributions, taking into account the cluster structure of 7Li. Gamow-Teller strengths for transitions to the lowest states in 7He are in remarkable agreement with results from ab initio Quantum Monte Carlo calculations. The neutron spectroscopic factor Sn=0.64±0.09 of the 7He ground state (7He=6He x n) is extracted by an R-matrix analysis. In the second part of the thesis the deuteron breakup has been studied in the 2H(e,e') reaction at Θ=180 . The present measurements were performed in March and April 2006 at the superconducting Darmstadt electron linear accelerator S-DALINAC at an incident electron energy E0=27.8 MeV and 74 MeV. At low momentum transfer (q=0.28 fm-1 and 0.73 fm-1, respectively

  5. Search for the p{sub 1/2{sup -}} resonance in {sup 7}He with the {sup 7}Li(d,{sup 2}He) reaction and measurement of the deuteron electrodisintegration under 180 at the S-DALINAC

    Energy Technology Data Exchange (ETDEWEB)

    Ryezayeva, N.

    2006-07-15

    The present work contains two parts, both devoted to the investigation of light nuclei. In the first part of the thesis the structure of the exotic {sup 7}He nucleus is studied. The disappearance of the usual magic numbers in extremely neutron-rich nuclei implies a considerable modification in the spin-orbit interaction. Recent experiments yield contradictory results about a possible existence of the p{sub 1/2{sup -}} spin-orbit partner of the {sup 7}He ground state with a dominant p{sub 3/2{sup -}} single-particle character. In order to clarify this question a study of the {sup 7}Li(d,{sup 2}He){sup 7}He reaction has been performed using a 171 MeV deuteron beam provided by the cyclotron at Kernfysisch Versneller Insituut (KVI) in Groningen. The experiment was carried out in April 2003. The setup at KVI offers a resolution {delta}E {approx} 150 keV (FWHM) in the measured spectra, better than the line width of the ground state of {sup 7}He. The unbound {sup 2}He system was identified by detecting coincidences between two protons with small relative energy. The data were taken over the angular range {theta}{sub cm}=0 -11.3 . A possible resonance at an excitation energy E{sub x}=(1.45{sub -0.5}{sup +0.7}) MeV with a width {gamma}=(2.0{sub -1.1}{sup +1.0}) MeV is suggested by a decomposition of the spectrum using known resonances, the breakup behaviour of {sup 7}He and quasifree charge-exchange contributions, taking into account the cluster structure of {sup 7}Li. Gamow-Teller strengths for transitions to the lowest states in {sup 7}He are in remarkable agreement with results from ab initio Quantum Monte Carlo calculations. The neutron spectroscopic factor S{sub n}=0.64{+-}0.09 of the {sup 7}He ground state ({sup 7}He={sup 6}He x n) is extracted by an R-matrix analysis. In the second part of the thesis the deuteron breakup has been studied in the {sup 2}H(e,e{sup '}) reaction at {theta}=180 . The present measurements were performed in March and April 2006 at the

  6. Ab initio calculation on accurate analytic potential energy functions and harmonic frequencies of c3∑+g and B1∏u states of dimer 7Li2

    Institute of Scientific and Technical Information of China (English)

    Yu Ben-Hai; Shi De-Heng; Sun Jin-Feng; Zhu Zun-Lue; Liu Yu-Fang; Yang Xiang-Dong

    2007-01-01

    The comparison between single-point energy scanning (SPES) and geometry optimization (OPT) in determining the equilibrium geometries of c3∑+g and B1∏u states of dimer 7Li2 is made at numerous basis sets by using a symmetryadapted-cluster configuration-interaction (SAC-CI) method in the Gaussian 03 program package. In this paper the difference of the equilibrium geometries obtained by SPES and by OPT is reported. The results obtained by SPES are found to be more reasonable than those obtained by OPT in full active space at the present SAC-CI level of theory. And the conclusion is attained that the cc-PVTZ is a most suitable basis set for these states. The calculated dissociation energies and equilibrium geometries are 0.8818 eV and 0.3090 nm for c3∑+g state, and 0.3668 eV and 0.2932 nm for B1∏u state respectively. The potential energy curves are calculated over a wide internuclear distance range from about 2.5a0 to 37a0 and have a least-squares fit into the Murrell-Sorbie function. According to the calculated analytic potential energy functions, the harmonic frequencies (ωe) and other spectroscopic data (ωeχe, Be and αe) are calculated. Comparison of the theoretical determinations at present work with the experiments and other theories clearly shows that the present work is the most complete effort and thus represents an improvement over previous theoretical results.

  7. Photoneutron cross sections measurements in {sup 9}Be, {sup 13}C e {sup 17}O with thermal neutron capture gamma-rays; Medidas das secoes de choque de fotoneutrons do {sup 9}Be, {sup 13}C e {sup 17}O com radiacao gama de captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, Renato

    2006-07-01

    Photoneutron cross sections measurements of {sup 9}Be, {sup 13}C and {sup 17}O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4{pi} geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm{sup 3}, 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  8. 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...

  9. 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.

  10. A test of the cosmogenic 10Be(meteoric)/9Be proxy for simultaneously determining basin-wide erosion rates, denudation rates, and the degree of weathering in the Amazon basin

    Science.gov (United States)

    Wittmann, H.; Blanckenburg, F.; Dannhaus, N.; Bouchez, J.; Gaillardet, J.; Guyot, J. L.; Maurice, L.; Roig, H.; Filizola, N.; Christl, M.

    2015-12-01

    We present an extensive investigation of a new erosion and weathering proxy derived from the 10Be(meteoric)/9Be(stable) ratio in the Amazon River basin. This new proxy combines a radioactive atmospheric flux tracer, meteoric cosmogenic 10Be, with 9Be, a trace metal released by weathering. Results show that meteoric 10Be concentrations ([10Be]) and 10Be/9Be ratios increase by >30% from the Andes to the lowlands. We can calculate floodplain transfer times of 2-30 kyr from this increase. Intriguingly however, the riverine exported flux of meteoric 10Be shows a deficit with respect to the atmospheric depositional 10Be flux. Most likely, the actual area from which the 10Be flux is being delivered into the mainstream is smaller than the basin-wide one. Despite this imbalance, denudation rates calculated from 10Be/9Be ratios from bed load, suspended sediment, and water samples from Amazon Rivers agree within a factor of 2 with published in situ 10Be denudation rates. Erosion rates calculated from meteoric [10Be], measured from depth-integrated suspended sediment samples, agree with denudation rates, suggesting that grain size-induced variations in [10Be] are minimized when using such sampling material instead of bed load. In addition, the agreement between erosion and denudation rates implies minor chemical weathering intensity in most Amazon tributaries. Indeed, the Be-specific weathering intensity, calculated from mobilized 9Be comprising reactive and dissolved fractions that are released during weathering, is constant at approximately 40% of the total denudation from the Andes across the lowlands to the Amazon mouth. Therefore, weathering in the Amazon floodplain is not detected.

  11. Study of elastic pion scattering from /sup 9/Be, /sup 28/Si, /sup 58/Ni, and /sup 208/Pb at 162 MeV. [Total and differential cross sections, scattering yields, scattering amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Devereux, M.J.

    1979-05-01

    Elastic pion scattering from /sup 9/Be, /sup 28/Si, /sup 58/Ni, and /sup 208/Pb at 162 MeV is analyzed and compared with an optical model theory which incorporates a pion--nucleon range. Excellent fits to the data are obtained in all but one case. The fitted values of the pion--nucleon range, as well as other fitted values are listed. 108 references.

  12. Nature of mixed symmetry 2{sup +} states in {sup 94}Mo from high resolution electron and proton scattering and line shape of the first excited 1/2{sup +} state in {sup 9}Be

    Energy Technology Data Exchange (ETDEWEB)

    Burda, Oleksiy

    2007-07-15

    The present work contains two parts. The first one is devoted to the investigation of mixed-symmetry structure in {sup 94}Mo and the second one to the astrophysical relevant line shape of the first excited 1/2{sup +} state in {sup 9}Be. In the first part of the thesis the nature of one- and two-phonon symmetric and mixed-symmetric 2{sup +} states in {sup 94}Mo is investigated with high-resolution inelastic electron and proton scattering experiments in a combined analysis. The (e,e') experiments were carried out at the 169 magnetic spectrometer at the S-DALINAC. Data were taken at a beam energy E e=70 MeV and scattering angles {theta}{sub e}=93 -165 . In dispersion-matching mode an energy resolution {delta}{sub E}=30-45 keV (full width at half maximum) was achieved. The (p,p') measurements were performed at iThemba LABS, South Africa, using a K600 magnetic spectrometer at a proton energy E p=200 MeV and scattering angles {theta}{sub p}=4.5 -26 . Typical energy resolutions were {delta}{sub E}{approx_equal}35 keV. The combined analysis reveals a dominant one-phonon structure of the transitions to the first and third 2{sup +} states, as well as an isovector character of the transition to the one-phonon mixed-symmetric state within the valence shell. Quantitatively consistent estimates of the one-phonon admixtures are obtained from both experimental probes when two-step contributions to the proton scattering cross sections are taken into account. In the second part of the thesis the line shape of the first excited 1/2{sup +} state in {sup 9}Be is studied. Spectra of the {sup 9}Be(e,e') reaction were measured at the S-DALINAC at an electron energy E e=73 MeV and scattering angles of 93 and 141 with high energy resolution up to excitation energies E{sub x}=8 MeV. The form factor of the first excited state has been extracted from the data. The astrophysical relevant {sup 9}Be({gamma},n) cross sections have been extracted from the (e,e') data. The

  13. Nature of mixed symmetry 2+ states in 94Mo from high resolution electron and proton scattering and line shape of the first excited 1/2+ state in 9Be

    International Nuclear Information System (INIS)

    The present work contains two parts. The first one is devoted to the investigation of mixed-symmetry structure in 94Mo and the second one to the astrophysical relevant line shape of the first excited 1/2+ state in 9Be. In the first part of the thesis the nature of one- and two-phonon symmetric and mixed-symmetric 2+ states in 94Mo is investigated with high-resolution inelastic electron and proton scattering experiments in a combined analysis. The (e,e') experiments were carried out at the 169 magnetic spectrometer at the S-DALINAC. Data were taken at a beam energy E e=70 MeV and scattering angles Θe=93 -165 . In dispersion-matching mode an energy resolution ΔE=30-45 keV (full width at half maximum) was achieved. The (p,p') measurements were performed at iThemba LABS, South Africa, using a K600 magnetic spectrometer at a proton energy E p=200 MeV and scattering angles Θp=4.5 -26 . Typical energy resolutions were ΔE≅35 keV. The combined analysis reveals a dominant one-phonon structure of the transitions to the first and third 2+ states, as well as an isovector character of the transition to the one-phonon mixed-symmetric state within the valence shell. Quantitatively consistent estimates of the one-phonon admixtures are obtained from both experimental probes when two-step contributions to the proton scattering cross sections are taken into account. In the second part of the thesis the line shape of the first excited 1/2+ state in 9Be is studied. Spectra of the 9Be(e,e') reaction were measured at the S-DALINAC at an electron energy E e=73 MeV and scattering angles of 93 and 141 with high energy resolution up to excitation energies Ex=8 MeV. The form factor of the first excited state has been extracted from the data. The astrophysical relevant 9Be(γ,n) cross sections have been extracted from the (e,e') data. The resonance parameters of the first excited 1/2+ state in 9Be are derived in a one-level R-matrix approximation. The deduced resonance parameters averaged

  14. Application of the authigenic 10Be/9Be dating method to Late Miocene-Pliocene sequences in the northern Danube Basin (Pannonian Basin System): Confirmation of heterochronous evolution of sedimentary environments

    Science.gov (United States)

    Šujan, Michal; Braucher, Régis; Kováč, Michal; Bourlès, Didier L.; Rybár, Samuel; Guillou, Valéry; Hudáčková, Natália

    2016-02-01

    Authigenic 10Be/9Be dating method was applied to lacustrine, deltaic and alluvial sequences of the northern Danube Basin (Pannonian Basin System), to bridge the insufficiency of geochronological data for the Late Miocene to Pliocene period. The measurements of 51 samples (both lacustrine and floodplain), ranging from 11.6 to 0.95 Ma are consistent with the existing magnetostratigraphic and biostratigraphic data standing mainly on the evolution degree of endemic mollusk fauna, mammals and dinocysts. This agreement confirms our assumption that the incoming beryllium fluxes remained constant over the studied time period and thus that the two initial 10Be/9Be ratios determined in actual Holocene/Late Pleistocene sediments (lacustrine and floodplain) are valid for these environments. The obtained ages indicate gradual progradation of the deltaic depositional systems across the Danube Basin with a clear time-transgressional character, replacing basin floor and shelfal environments. Deltaic sedimentation occurred firstly in the north at foothills of the Western Carpathians from 11.0 Ma, and changed to the alluvial environment after 10.5 Ma. At the same time (~ 10.5 Ma), the paleo-Danube deltaic system draining the Eastern Alps entered the study area from the Vienna Basin situated on the West. Later, the deltaic systems were merged in the central part of the basin and reached its southeastern margin at ~ 9.4 Ma. Regression of the Lake Pannon from the southernmost part of the study area is evidenced after 8.7 Ma. Alluvial deposition of meandering rivers lasting until 6.0-5.0 Ma followed and was interrupted by the early Pliocene basin inversion. Sedimentation of braided streams took place during the late Pliocene and Pleistocene, reflecting uplift of mountains surrounding the basin margins. This study documents the powerful potential of the authigenic 10Be/9Be dating method and its reliability in a basin with complicated tectonic and sedimentary history. It demonstrates that

  15. Measurements and calculations of neutron leakage spectra from slabs irradiated with 9Be(d, n)10B 2H(d, n)3He and Pu-Be neutrons

    International Nuclear Information System (INIS)

    The spectra of neutrons from the 9Be(d, n)10B, 2H(d, n)3He and Pu-Be sources passing through slabs of water, graphite, Al, Fe and Pb up to 20 cm in thickness were measured by a pulse height response spectrometer in the 1.5-15 MeV range. The measured leakage spectra have been compared with calculated results obtained using the three dimensional Monte-Carlo code MCNP-4A and point-wise cross sections from the ENDF/B-IV, ENDF/B-VI and JENDL-3.1 data files. A comparison of the measured and calculated data has shown that the MCNP-4A code with an appropriate library can reasonably approximate the measured leakage spectra

  16. Measurements and calculations of neutron leakage spectra from slabs irradiated with {sup 9}Be(d, n){sup 10}B {sup 2}H(d, n){sup 3}He and Pu-Be neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Olah, L.; Jordanova, J.; El-Megrab, A.M.; Darsono, Perez N.; Yousif, M.Y.A.; Csikai, J. [Institute of Experimental Physics, Kossuth University, Debrecen (Hungary); Fenyvesi, A.; Majdeddin, A.D. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary)

    1999-03-01

    The spectra of neutrons from the {sup 9}Be(d, n){sup 10}B, {sup 2}H(d, n){sup 3}He and Pu-Be sources passing through slabs of water, graphite, Al, Fe and Pb up to 20 cm in thickness were measured by a pulse height response spectrometer in the 1.5-15 MeV range. The measured leakage spectra have been compared with calculated results obtained using the three dimensional Monte-Carlo code MCNP-4A and point-wise cross sections from the ENDF/B-IV, ENDF/B-VI and JENDL-3.1 data files. A comparison of the measured and calculated data has shown that the MCNP-4A code with an appropriate library can reasonably approximate the measured leakage spectra.

  17. Excited states of hypernuclei (populated by low energetic separated K- beam)

    CERN Document Server

    Bamberger, A; Haddock, R; Lynen, U; Moszkowski, S; Piekarz, H; Piekarz, J; Pniewski, J; Povh, B; Ritter, H G; Soergel, Volker; Van Oers, W T H

    1972-01-01

    The experimental investigation of hypernuclei up to now has been done using emulsions and bubble chambers and therefore, with only 2 exemptions, all existing knowledge concerns hypernuclear ground states. The investigation of excited states in general is only possible using counter techniques, but these experiments could not be performed due to the low intensity of available K/sup -/-beams. At CERN a low energetic separated K-beam has been built, at which 1000 K /sup -/-mesons per burst can be stopped in a target of 6g/cm/sup 2/ thickness. At this beam an experiment looking for gamma -transitions in excited hypernuclei has been performed. In order to eliminate background gamma -radiation arising from kappa /sup -/ annihilation and de-excitation of residual nuclei, only light targets were used, namely /sup 6/Li, /sup 7/Li, /sup 9/Be, /sup 12/C and /sup 16/O. Hypernuclear transitions were found in /sup 4//sub Lambda /H and /sup 4//sub Lambda /He and possible transitions in /sup 6/Li and /sup 7/Li. The scatterin...

  18. 9Be(d,n)加速器中子源中子照相的研究%Research on neutron radiography of accelerator neutron source using D-Be reaction

    Institute of Scientific and Technical Information of China (English)

    裴宇阳; 邹宇斌; 郭之虞; 唐国有; 胥建国; 郭纪美; 张国辉; 郭利安

    2007-01-01

    加速器中子源比反应堆中子源更具灵活性,北京大学正在发展基于RFQ加速器的小型中子照相装置.为了更好地设计和优化此装置,实现高品质的中子照相,我们在北京大学4.5 MV静电加速器上建立了中子照相实验平台,包括科学级制冷、高灵敏度、低噪声的CCD数字成像系统,模拟基于厚铍靶9Be(d,n)反应RFQ中子源的条件,并利用此系统开展中子成像技术的研究.实验在像平面热中子注量率为5×103 cm-2·s-1或快中子注量率为3.7×104 cm-2·s-1的情况下获得了一定质量的热中子及快中子照片.当利用RFQ直线加速器强中子源时将可获得更高质量的图片,从而可以满足大多数的应用需要.

  19. Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and {sup 7}Li nuclear magnetic resonance studies of n-C{sub x}H{sub (2x+1)}OSO{sub 3}Li (x = 12, 14, 16, 18, and 20)

    Energy Technology Data Exchange (ETDEWEB)

    Hirakawa, Satoru [Yokohama City University, Graduate School of Nanobioscience (Japan); Morimoto, Yoshiaki [Yokohama City University, International College of Arts and Sciences (Japan); Honda, Hisashi, E-mail: hhonda@yokohama-cu.ac.jp [Yokohama City University, Graduate School of Nanobioscience (Japan)

    2015-04-15

    Electrical conductivity (σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C {sub x}H{sub (2x+1)}OSO{sub 3}Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C {sub x}H{sub (2x+1)}OSO{sub 3}Na and n-C {sub x}H{sub (2x+1)}OSO{sub 3}K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (ΔS). For n-C {sub 18}H{sub 37}OSO{sub 3}Li and n-C {sub 20}H{sub 41}OSO{sub 3}Li salts, each melting point produced a small ΔS{sub mp} value compared with the total entropy change in the solid phases (ΔS{sub tr1}+ΔS{sub tr2}). Additionally, Li {sup +} ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. {sup 7}Li NMR spectra of n-C {sub 18}H{sub 37}OSO{sub 3}Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li {sup +} ions are localized at asymmetric sites in the crystals.

  20. Total pion cross section measurements. Annual progress report, January 1, 1978--December 31, 1978

    International Nuclear Information System (INIS)

    The pion-nucleus total cross section runs were completed. The principal effort for the past year has been devoted to data analysis. Some preliminary results for the heavy elements have been submitted in a contributed paper. A paper on the Coulomb effects in the Klein--Gordon equation for pions has also been submitted. π +- data to be published include targets and energies for 4He, 23 - 90 MeV; 12C, 13C, 23 → 240 MeV; 6Li, 7Li, 9Be, 10B, 11B, 43 → 215 MeV; 16O, 18O, 40Ca, 44Ca, 48Ca, 43 → 240 MeV; 45Sc, 51V, Al, Cu, Sn, Ho, Pb, 60 → 215 MeV

  1. Communication of nuclear data progress: No.6 (1991)

    International Nuclear Information System (INIS)

    > (CNDP) in English is set up by Chinese Nuclear Committee and Chinese Nuclear Data center (CNDC). This is the sixth issue, in which the first part of CENDL-2 (Chinese Evaluated Nuclear Data Library, version 2.0) papers is published. The main purpose for making CENDL-2 is to develop and improve the CENDL-1. It includes the evaluation of 38 elements and isotopes with incident neutron energy from 10-5 eV to 20 MeV, which are 1H, 2H, 3He, 4He, 6Li, 7Li, 9Be, 10B, 11B, 14N, 16O, 19F,, Mg, Al, Si, S, K, Ti, V, Cr, Fe, Ni, Cu, Zr, Nb, Mo, Ag, 107Ag, 109Ag, Sn, Sb, 181Ta, W, 197Au, Pb, 238U, 237Np. The other evaluation reports of 16 elements and isotopes will be published in the supplement to CNDP No.6

  2. Contribution to the study of cluster structures in some light nuclei

    International Nuclear Information System (INIS)

    Excitation functions for the reactions: 6Li(α,α0)6Li, 6Li(α,d0)8Be, 7Li(α,α0)7Li, 7Li(α,α1)7Li, 7Li(α,t0)8Be and 7Li(α,p0)10Be have been measured, at several angles, in the incident energy regions: Esup(Lab)sub(α)=3.6 to 7.0 MeV for the 6Li+α system. The spins and parities of the resonances observed are determined by means of the R-matrix formalism using optical-model phase shifts. The characteristics of the resonances are following: for the 6Li+α, system, Jsup(π)=3+(2)+, Esub(x)(10B)=7.00 MeV, GAMMAsub(tot)=110 keV, GAMMAsub(α0)=80 keV, GAMMAsub(d0)=30 keV, GAMMAsub(d1)7Li+α system, Jsup(π)=5/2-, Esub(x)(11B)=14.53 MeV, GAMMAsub(tot)=204 keV, GAMMAsub(α0)=100 keV, GAMMAsub(t0)=40 keV, GAMMAsub(α1)+GAMMAsub(α2)=64 keV. The three-body theory of Brayshaw and Peierls is reexamined and discussed. The resonances have been interpreted as 'cluster resonances' of the three-cluster systems, 2α+d and 2α+t, respectively. The discret-ambiguity problem of the optical model has also been studied including spin-orbit potential for target spin

  3. Manifestation of nuclear cluster structure in Coulomb sums

    CERN Document Server

    Buki, A Yu

    2016-01-01

    Experimental Coulomb sum values of 6^Li and 7^Li nuclei have been obtained, extending the earlier reported momentum transfer range of Coulomb sums for these nuclei up to q = 0.750 ... 1.625 fm^-1. The dependence of the Coulomb sums on the momentum transfers of 6^Li and 7^Li is shown to differ substantially from similar dependences for all the other nuclei investigated. Relationship between the nuclear cluster structure and Coulomb sums has been considered. The momentum transfer value, above which the Coulomb sum becomes constant, is found to be related to the cluster isolation parameter x, which characterizes the degree of nuclear clusterization.

  4. Total helium production cross section from n + 10B interactions for ENDF/B-IV

    International Nuclear Information System (INIS)

    The total neutron-induced alpha production cross section for 10B was derived by summing the cross sections from the reactions (n,α0)7Li, (n,α1)7Li*(478 keV), and (n,n'α)6Li plus twice the reactions (n,t2α), (n,n'd2α), and (n,2np2α)

  5. Primordial Nucleosynthesis

    International Nuclear Information System (INIS)

    Primordial nucleosynthesis, or Big Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4He, D, 3He and 7Li, but also 6Li, 9Be, 11B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of ''constants'' or alternative theories of gravity.

  6. Neutrino-Nucleus Reaction Cross Sections for Light Element Synthesis in Supernova Explosions

    CERN Document Server

    Yoshida, T; Chiba, S; Kajino, T; Yokomakura, H; Kimura, K; Takamura, A; Hartmann, D H

    2008-01-01

    The neutrino-nucleus reaction cross sections of 4He and 12C are evaluated using new shell model Hamiltonians. Branching ratios of various decay channels are calculated to evaluate the yields of Li, Be, and B produced through the nu-process in supernova explosions. The new cross sections enhance the yields of 7Li and 11B produced during the supernova explosion of a 16.2 M_odot star model compared to the case using the conventional cross sections by about 10%. On the other hand, the yield of 10B decreases by a factor of two. The yields of 6Li, 9Be, and the radioactive nucleus 10Be are found at a level of 10^{-11} M_odot. The temperature of nu_{mu,tau}- and bar{nu}_{mu,tau}-neutrinos inferred from the supernova contribution of 11B in Galactic chemical evolution models is constrained to the 4.3 MeV to 6.5 MeV range. The increase in the 7Li and 11B yields due to neutrino oscillations is demonstrated with the new cross sections.

  7. Role of spin in heavy-ion reactions

    International Nuclear Information System (INIS)

    Some of the additional information gained by determining M-state populations in heavy-ion reactions are discussed. The extra information obtained from analyzing power measurements is illustrated by results of the 6Li + 58Ni and 7Li + 58Ni reactions. A comparison of differential cross-sections for elastic scattering at E/sub cm/ = 18.1 MeV is given. The data are seen to be rather similar. However, the tensor analyzing powers in the two cases are very different. Especially striking is the way the 7Li tensor analyzing power becomes large and negative at back angles. An interpretation of this difference was provided by the Heidelberg group, in terms of the different intrinsic shapes of 6Li and 7Li. Their spectroscopic quadrupole moments indicate that 6Li (Q = -.064 e fm2) is nearly spherical, whereas 7Li (Q = -3.66 e fm2) is strongly deformed and oblate. Top views are compared of an aligned 7Li and a 7Li whose orientation is random. The fat waist of the aligned oblate 7Li causes it to overlap more with the 58Ni target for a given impact parameter, which leads to greater absorption in the aligned case than in the random case. This difference is not present in the case of spherical 6Li. Thus by using aligned beams we are sensitive to real nuclear structure differences that we miss when we use beams with equal M-state populations. Other examples are discussed. 12 refs

  8. Study of the primordial lithium abundance

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at China Institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.

  9. Radiation-Induced Color Centers in LiF for Dosimetry at High Absorbed Dose Rates

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Ellis, S. C.;

    1980-01-01

    Color centers formed by irradiation of optically clear crystals of pure LiF may be analyzed spectrophotometrically for dosimetry in the absorbed dose range from 102 to 107 Gy. Routine monitoring of intense electron beams is an important application. Both 6LiF and 7LiF forms are commercially...

  10. Evaluation of light nuclides for fusion neutronics application

    International Nuclear Information System (INIS)

    Neutron nuclear data of 6Li, 7Li, 12C and 16O have been evaluated for JENDL-3. The methods of evaluation and the results are described. The present evaluated data are employed for the analysis of the Japan-US co-operative experiment using FNS. (author)

  11. Diode laser absorption spectroscopy of lithium isotopes

    Science.gov (United States)

    Olivares, Ignacio E.; González, Iván A.

    2016-10-01

    We study Doppler-limited laser intensity absorption, in a thermal lithium vapor containing 7Li and 6Li atoms in a 9 to 1 ratio, using a narrow-linewidth single-longitudinal-mode tunable external cavity diode laser at the wavelength of 670.8 nm. The lithium vapor was embedded in helium or argon buffer gas. The spectral lineshapes were rigorously predicted for D_1 and D_2 for the lithium 6 and 7 isotope lines using reduced optical Bloch equations, specifically derived, from a density matrix analysis. Here, a detailed comparison is provided of the predicted lineshapes with the measured 7Li-D_2, 7Li-D_1, 6Li-D_2 and 6Li-D_1 lines, in the case of high vapor density and with intensity above the saturation intensity. To our knowledge, this is the first time that such detailed comparison is reported in the open literature. The calculations were also extended to saturated absorption spectra and compared to measured Doppler-free 7Li-D_2 and 6Li-D_2 hyperfine lines.

  12. Photodisintegration of Lithium Isotopes

    Science.gov (United States)

    Wurtz, Ward Andrew

    We have performed a measurement of the photodisintegration of the lithium isotopes, 6Li and 7Li, using a monochromatic, polarised photon beam and a segmented neutron detector array which covers approximately ¼ of 4pi srad. Using time-of-flight and scintillator light-output spectra we separate the data into individual reaction channels. This work is motivated by the need to compare with recent theoretical predictions and to provide data for future theoretical work. For the photodisintegration of 6Li we took data at 12 photon energies between 8 and 35 MeV. We describe the data using a model consisting of two-body reaction channels and obtain angular distributions and absolute cross sections for many of these reaction channels. We compare our results with a recent Lorentz integral transform calculation (Bacca et al. Phys. Rev. C 69, 057001 (2004)). Our results are in reasonable agreement with the calculation, in contradiction with previous experimental results. For the photodisintegration of 7Li, we took data at 9 photon energies between 10 and 35 MeV. We obtain cross sections for the reaction channel 7Li + gamma → n + 6 Li(g.s.) at all photon energies with angular distributions at all but the highest energy. We obtain angular distributions and total cross sections for reaction channels involving excited states of the daughter nucleus, 6Li, at select energies. We hope that these measurements will provide incentive for new theoretical calculations. We observe neutrons that can only be described by the reaction channel 7Li + gamma → n + 6Li(10.0) which necessitates an excited state of 6Li with excitation energy Ex = 10.0 +/- 0.5 MeV that is not in the standard tables of excited states. ii

  13. Measurement of Secondary Neutron Emission Double-differential Cross Section for ~9Be Induced by 8.19 MeV Neutrons%8.19MeV中子与~9Be作用的次级中子双微分截面测量

    Institute of Scientific and Technical Information of China (English)

    张雅玲; 阮锡超; 姚泽恩; 黄翰雄; 李霞; 周祖英; 唐洪庆; 聂阳波; 鲍杰

    2011-01-01

    The secondary neutron emission double-differential cross section of 9Be induced by 8.19 MeV neutron was measured at 26 different angles from 20° to 150° by using the multi-detector fast neutron TOF spectrometer at the HI-13 Tandem Accelerator at China Institute of Atomic Energy(CIAE).The results were normalized to n-p scattering measurement.A special Monte-Carlo code which was validated with the MCNP-4C code was employed to analyze the measured data for the corrections of neutron flux attenuation,multiple scattering and finite geometry.The measured results were compared with the evaluated data and the other measurements.%用中国原子能科学研究院HI-13串列加速器上的多探测器快中子飞行时间谱仪,测量了8.19 MeV中子与9Be作用时,从20°到160°区间26个角度的次级中子双微分截面。测量截面以n-p散射截面作为标准进行归一。实验结果用Monte-Carlo方法进行了中子注量率衰减、多次散射和有限几何修正,并用MCNP-4C程序对所用的Monte-Carlo程序进行了验证。测量结果与评价数据以及其它实验室的数据进行了比较。

  14. Proton calibration of low energy neutron detectors containing (6)LiF

    Science.gov (United States)

    Benton, E. V.; Frank, A. L.

    1995-01-01

    The purpose of the present calibrations is to measure the proton response of the detectors with accelerated beams having energies within the region of maximum intensities in the trapped proton spectrum encountered in near-Earth orbit. This response is compared with the responses of the spaceflight detectors when related to proton exposures. All of the spaceflight neutron measurements have been accompanied by TLD absorbed doses measurements in close proximity within the spacecraft. For purposes of comparison, the spaceflight TLD doses are assumed to be proton doses.

  15. Determination of $^{6}Li - ^{4}He$ interaction from multi-energy scattering data

    CERN Document Server

    MacIntosh, R S; Kukulin, V I

    1999-01-01

    We present the first successful potential model description of Li-6 -- He-4 scattering. The differential cross-sections for three energies and the vector analyzing powers for two energies were fitted by a single potential with energy dependent imaginary components. An essential ingredient is a set of Majorana terms in each component. The potential was determined using a recently developed direct data-to-potential inversion method which is a generalisation of the IP S-matrix-to-potential inversion algorithm. We discuss the problems related to this phenomenological approach, and discuss the relationship of our results to existing and future theories.

  16. A Solution to Lithium Problem by Long-Lived Stau

    CERN Document Server

    Sato, Joe; Yamanaka, Masato

    2016-01-01

    We review a non-standard Big-Bang nucleosynthesis (BBN) scenario within the minimal supersymmetric standard model, and propose an idea to solve both ${}^{7}$Li and ${}^{6}$Li problems. Each problem is a discrepancy between the predicted abundance in the standard BBN and observed one. We focus on the stau, a supersymmetric partner of tau lepton, which is a long-lived charged particle when it is the next lightest supersymmetric particle and is degenerate in mass with the lightest supersymmetric particle. The long-lived stau forms a bound state with a nucleus, and provide non-standard nuclear reactions. One of those, the internal conversion process, accelerates the destruction of ${}^{7}$Be and ${}^{7}$Li, and leads to a solution to the ${}^{7}$Li problem. On the other hand, the bound state of the stau and ${}^{4}$He enhances productions of n, d, t, and ${}^{6}$Li. The over-production of ${}^{6}$Li could solve the ${}^{6}$Li problem. While, the over-productions of d and t could conflict with observations, and th...

  17. Precise and Sensitive Lithium Isotope Ratios by Quadrupole ICP-MS

    Science.gov (United States)

    Misra, S.; Froelich, P. N.

    2008-05-01

    We present a new method for the determination of 7Li/6Li with low Li consumption (99.99%), high Isotope Ratio precision (refined a single step ion chromatographic method to quantitatively recover (>99.99% yield) and separate Li from all matrix elements using small volume resin (2ml / 3.4meq AG50W-X8) and low elution volume (6ml of 0.5N HCl) with low procedural blanks (<500 fg/ml). We are currently testing inferences regarding foram chemical cleaning, species offsets and core top calibrations along the path toward creating a Cenozoic δ7Li record for seawater.

  18. Study of the Pion Production Mechanisms in Nucleus-Nucleus Collisions at the CERN SC using the Omicron Spectrometer

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to study the pion production mechanism in nucleus-nucleus collisions with the |3He and |1|2C beams of the CERN SC using the Omicron Spectrometer. The high intensity ion beams delivered now by the SC combined with the favourable characteristics of the Omicron Spectrometer offer a unique possibility of measuring very low cross-sections (typically in the order of 1 pb/(sr~MeV/c). In a first stage we will measure with an energy resolution of about 3~MeV the spectra of @p@+ emitted at 0|0 in two-body reactions induced by |3He ions of 910~MeV on targets of |6Li, |7Li, |9Be and |1|2C. The aim is to understand the reaction mechanisms and the nuclear wave functions most appropriate to describe the formation of nuclear bound states at momentum transfers of about 1.6@/1.7~GeV/c. The apparatus is shown in the figure. The same instrument will allow the measurement of the @p@+ inclusive spectra emitted at 0|0 after the interaction of the |1|2C|4|+ beam at 1032 MeV with the same targets. At 86 ...

  19. Production of secondary particles and nuclei in cosmic rays collisions with the insterstellar gas using the {\\tt FLUKA} code

    CERN Document Server

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

    2015-01-01

    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...

  20. Stellar models with microscopic diffusion and rotational mixing; 1, application to the sun

    CERN Document Server

    Chaboyer, B; Pinsonneault, M H; Chaboyer, Brian; Demarque, P; Pinsonneault, M H

    1994-01-01

    The Yale stellar evolution code has been modified to include the combined effects of diffusion and rotational mixing on ^1H, ^4He and the trace elements ^3He, ^6Li, ^7Li, and ^9Be. The interaction between rotational mixing and diffusion is studied by calculating a number of calibrated solar models. The rotational mixing inhibits the diffusion in the outer parts of the models, leading to a decrease in the envelope diffusion by 25 -- 50\\%. Conversely, diffusion leads to gradients in mean molecular weight which can inhibit the rotational mixing. The degree to which gradients in mean molecular weight inhibits the rotational mixing is somewhat uncertain. A comparison to the observed solar oblateness suggests that gradients in the mean molecular weight play a smaller role in inhibiting the rotational mixing previously believed. This is reinforced by the fact that the model with the standard value for the inhibiting effect of mean molecular weight on the rotational mixing depletes no Li on the main sequence. This is...

  1. Disentangling complete and incomplete fusion for 9Be+187Re system at near barrier energies

    International Nuclear Information System (INIS)

    The breakup of projectile before fusion leads to some unusual fusion mechanisms like incomplete fusion (ICF) and sequential complete fusion (SCF). Experimentally, it is not possible to separate SCF events from direct complete fusion (DCF). However, the complete fusion and incomplete fusion can be measured separately. Theoretically it is very difficult to calculate the complete and incomplete fusion cross section separately using different models. Very recently A. Diaz-Torres has developed a computer code platypus based on classical dynamical model wherein the complete and incomplete fusion cross sections are calculated separately. But this model is found to work very well at energies above the barrier energy. Here we have attempted to extrapolate the results of the code platypus by using simple Wong's formula in conjunction with the energy dependent Woods-Saxon potential (EDWSP) in the below barrier energy region

  2. Total cross-sections for reactions induced by oxygen-18 on lithium

    Energy Technology Data Exchange (ETDEWEB)

    Diaco, T.; Friedli, C.; Lerch, P.

    1987-01-01

    In order to determine traces of lithium by Heavy Ion Activation Analysis (HIAA), the yield curves and the excitation functions for 9 nuclear reactions induced by /sup 18/O ions on /sup 6/Li and /sup 7/Li, were determined in the 10 to 40 MeV energy range. The best yields were obtained with the /sup 7/Li(/sup 18/O,..cap alpha..n)/sup 20/F and the /sup 6/Li(/sup 18/O,2..cap alpha..)/sup 16/N reactions. The first reaction shows a maximum cross-section of 1.02+-0.09 barn for a 26 MeV /sup 18/O ion beam, thus leading to a fast, non-destructive, selective and sensitive determination of traces of lithium.

  3. Influence of projectile breakup on complete fusion

    Indian Academy of Sciences (India)

    A Mukherjee; M K Pradhan

    2010-07-01

    Complete fusion excitation functions for 11,10B+159Tb and 6,7Li+159Tb have been reported at energies around the respective Coulomb barriers. The measurements show significant suppression of complete fusion cross-sections at energies above the barrier for 10B+159Tb and 6,7Li+159Tb reactions, when compared to those for 11B+159Tb. The comparison shows that the extent of suppression of complete fusion cross-sections is correlated with the -separation energies of the projectiles. Also, the measured incomplete fusion cross-sections show that the -particle emanating channel is the favoured incomplete fusion process. Inclusive measurement of the -particles produced in 6Li+159Tb reaction has been carried out. Preliminary CDCC calculations carried out to estimate the - yield following 6Li breaking up into + fail to explain the measured -yield. Transfer processes seem to be important contributors.

  4. Error propagation with R-matrix model fitting

    Institute of Scientific and Technical Information of China (English)

    CHEN; Zhenpeng(陈振鹏); ZHANG; Rui(张瑞); SUN; Yeying(孙业英); LIU; Tingjin(刘廷进)

    2003-01-01

    The error propagation features with R-matrix model fitting 7Li, 11B and 17O systems have been researched systematically. Some laws of error propagation have been revealed, an experience formula for describing standard error propagation has been established, and the most possible error range for evaluated standard cross section of 6Li (n, α), 10B (n, α) and 10B (n, α1) has been determined.

  5. Production of $^{6}_{\\Lambda}$H and $^{7}_{\\Lambda}$H with the (K$^{-}_{stop}$,$\\pi^+$) reaction

    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; D'Erasmo, G; Dalena, B; 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; Lenti, V; Lucherini, V; Manzari, V; Marcello, S; Maruta, T; Mirfakharai, N; Mori, F D; Morra, O; Nagae, T; Outa, H; Pace, E; Pallotta, M; Palomba, M; Pantaleo, A; Panzarasa, A; Paticchio, V; Piano, S; Pompili, F; Rui, R; Santo, D D; Simonetti, G; Tereshchenko, V V; Tomassini, S; Toyoda, A; Wheadon, R; Zenoni, A; perov, A K

    2006-01-01

    The production of neutron rich $\\Lambda$-hypernuclei via the ($K^-_stop$,$\\pi^+$) reaction has been studied using data collected with the FINUDA spectrometer at the DA$\\Phi$NE $\\phi$-factory (LNF). The analysis of the inclusive $\\pi^+$ momentum spectra is presented and an upper limit for the production of $^6_\\Lambda$H and $^7_\\Lambda$H from $^6$Li and $^7$Li, is assessed for the first time.

  6. The methods of multiparameter correlation measurements for the study of nuclear reactions

    International Nuclear Information System (INIS)

    The methods and procedures of multi-parameter correlation experiments for the study of nuclear reactions are developed. Computerized measurement system allows to determine the energy of reaction products, their charge and mass, to register and analyze the time and energy correlations of two- or three-particle coincident events. Developed system was tested and used in the experiments for the study of binary and three particle reactions d + 6Li and α + 7Li

  7. Lithium isotope separation

    International Nuclear Information System (INIS)

    Published methods for 6Li-7Li lithium isotope separation have been reviewed. Future demand for 6Li, whose main use will be as a tritium breeder in blankets surrounding the core of DT fusion power reactors, is likely to exceed 5 Mg/a in the next century. The applicability of the various available methods to such a large scale production rate has been assessed. Research on improving the effectiveness of current lithium isotope separation processes has been carried out worldwide in several major areas during the past decade; these include two-phase chemical exchange systems, ion exchange resin chromatography, highly isotope-selective techniques like laser photoactivation and radiofrequency spectroscopy. Chemical exchange systems appear to offer good potential in the near term for 6Li enrichment

  8. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    Science.gov (United States)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  9. All-optical production and transport of a large 6Li quantum gas in a crossed optical dipole trap

    Science.gov (United States)

    Gross, Ch.; Gan, H. C. J.; Dieckmann, K.

    2016-05-01

    We report on an efficient production scheme for a large quantum degenerate sample of fermionic lithium. The approach is based on our previous work on narrow-line 2 S1 /2→3 P3 /2 laser cooling resulting in a high phase-space density of up to 3 ×10-4 . This allows utilizing a large-volume crossed optical dipole trap with a total power of 45 W , leading to high loading efficiency and 8 ×106 trapped atoms. The same optical trapping configuration is used for rapid adiabatic transport over a distance of 25 cm in 0.9 s , and subsequent evaporative cooling. With optimized evaporation we achieve a degenerate Fermi gas with 1.7 ×106 atoms at a temperature of 60 nK , corresponding to T /TF=0.16 (2 ) . Furthermore, the performance is demonstrated by evaporation near a broad Feshbach resonance creating a molecular Bose-Einstein condensate of 3 ×105 lithium dimers.

  10. All-optical production and transport of a large $^6$Li quantum gas in a crossed optical dipole trap

    CERN Document Server

    Gross, Ch; Dieckmann, K

    2016-01-01

    We report on an efficient production scheme for a large quantum degenerate sample of fermionic lithium. The approach is based on our previous work on narrow-line $ 2S_{1/2}\\rightarrow 3P_{3/2} $ laser cooling resulting in a high phase-space density of up to $3\\times10^{-4}$. This allows utilizing a large volume crossed optical dipole trap with a total power of $45\\,\\textrm{W}$, leading to high loading efficiency and $8\\times10^6$ trapped atoms. The same optical trapping configuration is used for rapid adiabatic transport over a distance of $25\\,\\textrm{cm}$ in $0.9\\,\\textrm{s}$, and subsequent evaporative cooling. With optimized evaporation we achieve a degenerate Fermi gas with $1.7\\times 10^{6}$ atoms at a temperature of $60 \\, \\textrm{nK}$, corresponding to $T/T_{\\text{F}}=0.16\\left(2 \\right)$. Furthermore, the performance is demonstrated by evaporation near a broad Feshbach resonance creating a molecular Bose-Einstein condensate of $3\\times10^5$ lithium dimers.

  11. SoLid: Search for Oscillation with a 6Li Detector at the BR2 research reactor

    CERN Document Server

    Michiels, Ianthe

    2016-01-01

    In the past decades, various nuclear reactor neutrino experiments have measured a deficit in the flux of antineutrinos coming from the reactor at short reactor-detector distances, when compared to theoretical calculations. One of the experiments designed to investigate this reactor antineutrino anomaly is the SoLid experiment. It uses the compact BR2 research reactor from the SCK-CEN in Mol, Belgium, to perform reactor antineutrino flux measurements at very short baseline. These proceedings discuss the general detection concepts of the SoLid experiment and its novel detector technology. The performance of the SoLid design is demonstrated with some results of the analysis of the data gathered with the experiment's first large scale test module, SM1.

  12. Development of Li compound embedded with CaSO4:Dy TL pellet for neutron measurement

    International Nuclear Information System (INIS)

    Personal neutron dosimetry is quite a difficult area because a neutron is always accompanied with gamma radiation, which is required of a the capability for mixed field dosimetry. CaSO4: Dy phosphor is known to have a very high sensitivity to gamma, but the neutron capture cross section of the constituents of CaSO4:Dy are so small that the interactions between the thermal neutron and the phosphor are rare. One method to improve the neutron interaction is by introducing an impurity ion with a large thermal neutron captures cross section into the phosphor to act as a neutron target centre such as 6Li. In neutron-gamma mixed radiation fields, if two detectors for the 6Li-7Li compounds embedded CaSO4:Dy TL pellets are used, a 6Li-compound embedded pellet can detect the neutron and gamma radiation together, and the other pellet can only detect the gamma radiation. Recently Korea Atomic Energy Research Institute (KEARI) has developed a new type of CaSO4:Dy TL materials embedded with phosphorous (KCT-300) to detect beta and gamma radiation with a very high sensitivity. This paper presents the development of CaSO4:Dy TL pellets embedded with 6Li compound for a thermal neutron measurement, and the detection method of the neutron and gamma dose in mixed fields with CaSO4:Dy TL pellets embedded with a 6Li compound(KCT-306) and CaSO4:Dy TL pellets embedded with a 7Li compound(KCT-307) is introduced. The net neutron sensitivity of CaSO4:Dy TL pellets embedded with 6Li compound developed in this study is about 2 times higher than that of the TLD-600 (Harshaw Co.) dosimeter which is available in the open market

  13. Immunofluorescence Detection of γ-H2AX Foci Induced by ~7Li Ions and γ-rays Radiation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    DNA double strand breaks (DSBs) are considered as the most critical type of lesions. Correct and complete repair of DSBs guarantees cellular survival, while incorrect repair and residual DNA damage may lead to cell killing, mutation or transformation. Following induction of DNA double strand breaks,

  14. Verification test for three WindCubeTM WLS7 LiDARs at the Hoevsoere test site

    Energy Technology Data Exchange (ETDEWEB)

    Gottschall, J.; Courtney, M.

    2010-05-15

    The report describes the procedure of testing ground-based WindCubeTM lidars (manufactured by the French company Leosphere) at the Hoevsoere test site in comparison to reference sensors mounted at a meteorological mast. Results are presented for three tested units - in detail for unit WLS7-0062, and in a summary for units WLS7-0064 and WLS7-0066. The verification test covers the evaluation of measured mean wind speeds, wind directions and wind speed standard deviations. The data analysis is basically performed in terms of different kinds of regression analyses. (author)

  15. Trojan Horse Particle Invariance: An Extensive Study

    Science.gov (United States)

    Pizzone, R. G.; Spitaleri, C.; Sergi, M. L.; Lamia, L.; Tumino, A.; Bertulani, C. A.; Blokhintsev, L.; Burjan, V.; Kroha, V.; La Cognata, M.; Mrazek, J.; Mukhamedzhanov, A. M.; Spartá, R.

    2014-08-01

    In the last decades, the Trojan Horse method (THM) has played a crucial role for the measurement of several particle (both neutron and charged one) induced cross sections for reactions of astrophysical interest. To better understand its cornerstones and its applications to physical cases, many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance proves the relatively simple approach allowed by the pole approximation and sheds light in the involved reaction mechanisms. Here we shortly review the complete work for the binary 2H(d,p)3H, 6Li(d, α)4He, 6Li(p, α)3He, 7Li(p, α)4He reactions, by using the quasi free reactions after break-ups of different nuclides. Results are compared assuming the 6Li and 3He break-up in the case of the d(d,p)t, 6Li(d, α)4He reactions and considering the 2H and 3He break-up for 6Li(p, α)3He, 7Li(p, α)4He reactions. These results, regardless of the Trojan Horse particle or the break-up scheme, confirms the applicability of the standard description of the THM and suggests the independence of binary indirect cross section on the chosen Trojan Horse nuclei for a whole spectra of different cases. This gives a strong basis for the understanding of the quasi-free mechanism which is the foundation on which the THM lies.

  16. Variation of lithium isotope composition in the marine environment: A preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Luiheung; Edmond, J.M. (Louisiana State Univ., Baton Rouge (USA))

    1988-06-01

    The Li isotopic compositions of ocean waters, lake water, hydrothermal solutions, altered and unaltered basalts have been determined using the technique of thermal ionization mass spectrometry of lithium tetraborate. Seawater appears to be homogeneous in Li isotopic composition. The mean {delta}{sup 6}Li value is {minus}32.3 {plus minus} 0.5{per thousand}, relative to an isotopic standard. Three lakes studied (Lake Tanganyika, Caspian Sea and Dead Sea) yield {delta}{sup 6}Li similar to the seawater isotopic composition. A fresh basalt glass from 21{degree}N, East Pacific Rise displays a {delta}{sup 6}Li value of {minus}4.7{per thousand}. A hydrothermal solution from a 21{degree}N vent field has {delta}{sup 6}Li of {minus}10{per thousand}, indicating incomplete extraction of Li from the igneous minerals or partial retention in secondary phases. The alteration margin of a basalt from the Mid-Atlantic Ridge has {delta}{sup 6}Li of {minus}8.4{per thousand}. The isotope data of submarine basalts suggest preferential removal of {sup 6}Li from seawater into alteration minerals during low temperature weathering. The {delta}{sup 6}Li values of two hydrothermal solutions from Guaymas Basin were found to be {minus}5{per thousand} and {minus}10{per thousand}. The results can be interpreted as the net effect of Li addition from basalt and sediments and incorporation in hydrothermal precipitates as the hydrothermal fluids interact with basin sediments. The observed enrichment of {sup 7}Li in seawater relative to submarine hydrothermal solutions, its principal Li input, is tentatively attributed to isotopic fractionation associated with low temperature alteration of sea floor basalt and incorporation in authigenic sediments. It appears that the Li isotope system may have characteristics that can resolve the mass balance of Li in the ocean.

  17. Extraction of tritium from ceramic breeder material

    International Nuclear Information System (INIS)

    The first generation of fusion reactors will use deuterium and tritium as fuel since this reaction takes place at relatively low temperature. Since tritium is not available in nature, it must be produced in the fusion reactor blanket which surrounds the plasma zone. The lithium bearing compound is available in plenty in earths crust and by absorbing neutron, lithium produces tritium by the reactions 6Li (n, α) T and 7Li (n, n'α) T. Natural lithium consists of 93% 7Li and the remaining 7% as 6Li. Since the inelastic scattering of 7Li with fast neutrons produces one tritium and one neutron, more than one tritium atom can be produced per neutron. Hence by suitably designing the lithium blanket, more than one tritium atom per fusion reaction can be produced. In the absence of thermonuclear reactions, the (D,T) neutrons which are energetic 14-MeV neutrons, are produced in the accelerator based neutron generators. In order to ensure that sufficient amount of tritium would be produced in the future fusion reactor blankets, experiments are carried out to irradiate the lithium assembly using the available neutron source and measurements are done to estimate the tritium breeding. Also, it is required to extract the tritium produced in the lithium blanket. This work consists of tritium breeding measurement technique and a design of tritium extraction system. (author)

  18. Optical absorption of isotopically enriched Li{sub 2}B{sub 4}O{sub 7} single crystals irradiated by thermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Burak, Ya.V. E-mail: burak@ifo.lviv.ua; Adamiv, V.T.; Teslyuk, I.M.; Shevel, V.M

    2004-12-01

    Induced absorption spectra in the range 200-900 nm at 77 and 290 K for Li{sub 2}B{sub 4}O{sub 7} single crystals, isotopically Li and B enriched are presented after irradiation of these crystals by thermal neutrons with fluence 1.8x10{sup 16} cm{sup -2}. The dependence of induced absorption spectra on the isotope composition was revealed: for {sup 6}Li{sub 2}{sup 10}B{sub 4}O{sub 7} and {sup 7}Li{sub 2}{sup 10}B{sub 4}O{sub 7} crystals intensive band in the region of 280-294 nm was observed. Under substitution of {sup 7}Li isotope by {sup 6}Li in the lithium tetraborate lattice no changes in the absorption spectra were observed. The nuclear reaction {sup 10}B(n,{alpha}){sup 7}Li is proposed to be the main mechanism of formation of the radiation defects.

  19. 2p1v states populated in 135Te from 9Be induced reactions with a 132Sn beam

    Energy Technology Data Exchange (ETDEWEB)

    Allmond, James M [ORNL; Stuchbery, Andrew E [ORNL; Brown, Alex [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University; Beene, James R [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Gross, Carl J [ORNL; Liang, J Felix [ORNL; Padilla-Rodal, Elizabeth [Universidad Nacional Autonoma de Mexico (UNAM); Radford, David C [ORNL; Varner Jr, Robert L [ORNL; Ayres, A. [University of Tennessee, Knoxville (UTK); Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Bey, A. [University of Tennessee, Knoxville (UTK); Bingham, C. R. [University of Tennessee, Knoxville (UTK); Howard, Meredith E [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK); Manning, Brett M [ORNL; Mueller, Paul Edward [ORNL; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Peters, William A [ORNL; Ratkiewicz, Andrew J [ORNL; Schmitt, Kyle [University of Tennessee, Knoxville (UTK); Shapira, Dan [ORNL; Smith, Michael Scott [ORNL; Stone, N. J. [University of Tennessee, Knoxville (UTK); Stracener, Daniel W [ORNL; Yu, Chang-Hong [ORNL

    2014-01-01

    Gamma-ray transitions in $^{134}$\\textrm{Te}, $^{135}$\\textrm{Te}, and $^{136}$\\textrm{Te} were measured from $^{9}$\\textrm{Be} induced reactions with a radioactive $^{132}$\\textrm{Sn} beam at a sub-Coulomb barrier energy of $3$~MeV per nucleon using particle-$\\gamma$ coincidence spectroscopy. The transitions were selected by gating on alpha-like particles in a \\textrm{CsI} detector following a combination of ($^{9}$\\textrm{Be},$\\alpha 1n$), ($^{9}$\\textrm{Be},$\\alpha 2n$), and ($^{9}$\\textrm{Be},$\\alpha 3n$) reactions. Distorted wave Born approximation calculations suggest little to no contribution from the ($^{9}$\\textrm{Be},$^{7}$\\textrm{He}), ($^{9}$\\textrm{Be},$^{6}$\\textrm{He}), and ($^{9}$\\textrm{Be},$^{5}$\\textrm{He}) direct reactions. Gamma-ray transitions from previously known $2^+\\otimes \

  20. Theoretical study of the elastic breakup of weakly bound nuclei at near barrier energies

    CERN Document Server

    Otomar, D R; Lubian, J; Canto, L F; Hussein, M S

    2015-01-01

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

  1. Quantum Defect Theory description of weakly bound levels and Feshbach resonances in LiRb

    CERN Document Server

    Pérez-Ríos, Jesús; Chen, Yong P; Greene, Chris H

    2014-01-01

    The multichannel quantum defect theory (MQDT) in combination with the frame transformation (FT) approach is applied to model the Fano-Feshbach resonances measured for $^{7}$Li$^{87}$Rb and $^{6}$Li$^{87}$Rb [Marzok {\\it et al.} Phys. Rev. A {\\bf 79} 012717 (2009)]. The MQDT results show a level of accuracy comparable to that of previous models based on direct, fully numerical solutions of the the coupled channel Schr\\"odinger equations (CC). Here, energy levels deduced from 2-photon photoassociation spectra for $^{7}$Li$^{85}$Rb are assigned by applying the MQDT approach, obtaining the bound state energies for the coupled channel problem. Our results confirm that MQDT yields a compact description of photoassociation observables as well as the Fano-Feshbach resonance positions and widths.

  2. Calculation of the elastic collision properties of Na and Li atoms at ultracold temperature

    Institute of Scientific and Technical Information of China (English)

    Zhang Ji-Cai; Zhang Ying; Du Bing-Ge; Sun Jin-Feng

    2009-01-01

    This paper firstly reports a theoretical study of elastic scattering properties in a mixture of 23Na and 7Li atoms at cold and ultracold temperatures in detail.Based on the new constructed accurate singlet X1∑+g and the triplet a3∑+u states interatomic potentials for 23Na7Li mixture,it calculates the scattering lengths and the effective ranges by three computational methods,and obtains good agreements.Using the mass scaling method,it also calculates 23Na6Li scattering lengths and s-wave and total elastic cross sections,whose rich resonance structures were found and interpreted in terms of quasibound diatomic levels trapped behind a centrifugal barrier.

  3. Experiments on the nuclear interactions of pions. Progress report

    International Nuclear Information System (INIS)

    Progress is reported on the following studies: (1) quasi-free-scattering of pions from 3He and 4He; (2) elastic scattering of pions from 3He and 4He; (3) pion absorption on 3He and 4He; (4) the reaction 2H(π+, 2p) at low energies; (5) quasi-free pion scattering on 6Li and 12C; (6) a study of the (π,π d) reaction in 6Li, 7Li, 12C, and 13C; (7) a study of the Δ++ resonance in 11B; (8) search for heavy neutrinos in the decay, π+ → μ+ + nu; (9) pionium; (10) a search for fractionally charged particles; (11) measurement of the π-, π0 mass difference; (12) y-scaling in the (e,e') reaction at high energies; (13) a study of the Δ-resonance in high energy electron scattering; and (14) CEBAF spectrometers

  4. Infrared length scale and extrapolations for the no-core shell model

    CERN Document Server

    Wendt, K A; Papenbrock, T; Sääf, D

    2015-01-01

    We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the $A$-body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of $A$ nucleons in the NCSM space to that of $A$ nucleons in a $3(A-1)$-dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for $^{6}$Li. We apply our result and perform accurate IR extrapolations for bound states of $^{4}$He, $^{6}$He, $^{6}$Li, $^{7}$Li. We also attempt to extrapolate NCSM results for $^{10}$B and $^{16}$O with bare interactions from chiral effective field theory over tens of MeV.

  5. Infrared length scale and extrapolations for the no-core shell model

    Science.gov (United States)

    Wendt, K. A.; Forssén, C.; Papenbrock, T.; Sääf, D.

    2015-06-01

    We precisely determine the infrared (IR) length scale of the no-core shell model (NCSM). In the NCSM, the A -body Hilbert space is truncated by the total energy, and the IR length can be determined by equating the intrinsic kinetic energy of A nucleons in the NCSM space to that of A nucleons in a 3 (A -1 ) -dimensional hyper-radial well with a Dirichlet boundary condition for the hyper radius. We demonstrate that this procedure indeed yields a very precise IR length by performing large-scale NCSM calculations for 6Li. We apply our result and perform accurate IR extrapolations for bound states of 4He,6He,6Li , and 7Li . We also attempt to extrapolate NCSM results for 10B and 16O with bare interactions from chiral effective field theory over tens of MeV.

  6. Experiments on the nuclear interactions of pions. Progress report

    International Nuclear Information System (INIS)

    Experiments reported include: π+ + d → 2p; (π+,pp) and (π-,pn) reactions in 3He; quasi-free pion scattering on 6Li and 12C; (π+,π+d) reaction in 6Li, 7Li, 12C and 13C; a study of the Δ++ resonance in 11B; eta production on 3He; inelastic scattering of pions from 3He and 4He; pion elastic scattering from He isotopes; anti-proton absorption in heavy nuclei; a search for heavy neutrinos; pionium; mass difference between negative and neutral pions; a search for fractionally charged particles; search for μ+ → e+ + γ; y-scaling in inelastic electron scattering; and electroproduction of the delta. 9 refs., 8 figs

  7. Mechanisms of Li-projectile breakup-up

    International Nuclear Information System (INIS)

    Various experimental and theoretical features observed in recent studies of break-up of 6Li and 7Li projectiles in the field of atomic nuclei are discussed, in particular for the transitional energy regime of 10-30 MeV/amu. The discussion is organized as three independent lectures presented at the International School on Nuclear Physics, Kiev (UkSSR), 28 May - 8 June, 1990. After a survey on the main experimental facts and on the basic reaction mechanisms, current theoretical approaches are illustrated by an application to the analysis of elastic break-up of 156 MeV 6Li projectiles. Finally Coulomb break-up is discussed as a novel tool of laboratory nuclear astrophysics. (orig.)

  8. Formates and dithionates: sensitive EPR-dosimeter materials for radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lund, E. [Department of Medicine and Care, Radiation Physics, Faculty of Health Sciences, University of Linkoeping, S-581 85 Linkoeping (Sweden)]. E-mail: eva.lund@imv.liu.se; Gustafsson, H. [Department of Medicine and Care, Radiation Physics, Faculty of Health Sciences, University of Linkoeping, S-581 85 Linkoeping (Sweden); Danilczuk, M. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Sastry, M.D. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Lund, A. [Chemical Physics Laboratory, IFM, University of Linkoeping, S-581 83 Linkoeping (Sweden); Vestad, T.A. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Malinen, E. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Hole, E.O. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Sagstuen, E. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)

    2005-02-01

    Polycrystalline formates and dithionates are promising materials for EPR dosimetry, as large yields of radiation induced stable radicals are formed with a linear dose response. Rapid spin relaxation rates were detected in many of the substances, indicating that a high microwave power can be applied during EPR acquisition in order to improve sensitivity. Different techniques used to further improve the sensitivity, such as the replacement of {sup 7}Li with {sup 6}Li or exchange of protons with deuterons in the corresponding crystalline matrices and metal ion doping are discussed. It is concluded that formates and dithionates may be up to 10 times as sensitive as L-{alpha}-alanine.

  9. Jacobi no-core shell model for p-shell nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Liebig, S.; Nogga, A. [Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, JARA - High Performance Computing, Juelich (Germany); Meissner, U.G. [Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, JARA - High Performance Computing, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany)

    2016-04-15

    We introduce an algorithm to obtain coefficients of fractional parentage for light p-shell nuclei. The coefficients enable one to use Jacobi coordinates in no-core shell model calculations separating off the center-of-mass motion. Fully antisymmetrized basis states are given together with recoupling coefficients that allow one to apply two- and three-nucleon operators. As an example, we study the dependence on the harmonic oscillator frequency of {sup 3}H, {sup 4}He, {sup 6}He, {sup 6}Li and {sup 7}Li and extract their binding and excitation energies. The coefficients will be made openly accessible as HDF5 data files. (orig.)

  10. Several Light Nulcie Evaluations Testing With LLNL Pulsed Sphere Benchmarks

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Huan-yu

    2012-01-01

    <正>In this work, Lawrence Livermore pulsed sphere experiments were modeled using Monte Carlo N-particle code (MCNP) for the purpose of benchmarking the new release of nuclear data librarys (CENDL-3[1], ENDF/B-Ⅶ.1[2], JENDL-4.0[3]). This program consisted of 12 different spheres, including 6 Li, 7Li, Be, C, N, O, LiD, Air, H2O, D2O, polythene and teflon. The calculated results were compared to experimental results[4-5].

  11. Jacobi no-core shell model for p-shell nuclei

    Science.gov (United States)

    Liebig, S.; Meißner, U.-G.; Nogga, A.

    2016-04-01

    We introduce an algorithm to obtain coefficients of fractional parentage for light p-shell nuclei. The coefficients enable one to use Jacobi coordinates in no-core shell model calculations separating off the center-of-mass motion. Fully antisymmetrized basis states are given together with recoupling coefficients that allow one to apply two- and three-nucleon operators. As an example, we study the dependence on the harmonic oscillator frequency of 3H, 4He, 6He, 6Li and 7Li and extract their binding and excitation energies. The coefficients will be made openly accessible as HDF5 data files.

  12. Jacobi no-core shell model for p-shell nuclei

    CERN Document Server

    Liebig, S; Nogga, A

    2015-01-01

    We introduce an algorithm to obtain coefficients of fractional parentage for light $p$-shell nuclei. The coefficients enable to use Jacobi coordinates in no-core shell model calculations separating off the center-of-mass motion. Fully antisymmetrized basis states are given together with recoupling coefficients that allow one to apply two- and three-nucleon operators. As an example, we study the dependence on the harmonic oscillator frequency of $^3$H, $^4$He, $^6$He, $^6$Li and $^7$Li and extract their binding and excitation energies. The coefficients will be made openly accessible as HDF5 data files.

  13. 吉林陨石锂同位素相对丰度的初步探讨

    Institute of Scientific and Technical Information of China (English)

    李肇辉

    1977-01-01

    Relative abundances of lithium isotopes are determined for Kirin chcndric meteorite and Hainan tektite with ion microprobe mass spectrometer. The appareut results of 7Li/6Li are 17.03±7 and 12.18±1.67 for Kirin ehondric meteorite and Hainan tektite respectively. If this result can be taken as a reflection of the real case, an anomalous distribution with respect, to lithium isotopes in micro-area scale is thus evidenced in Kirin meteorites. Possible reasons are suggested for this anomaly,

  14. Production of {sup 48}V in a nuclear reactor via secondary tritons

    Energy Technology Data Exchange (ETDEWEB)

    Siri, S. [Comision Nacional de Energia Atomica, Centro Atomico Ezeiza, Gerencia de Capacitacion, Quimica Nuclear y Ciencias de la Salud, Ezeiza, Buenos Aires (Argentina); Cohen, I.M. [Univ. Tecnologica Nacional, Dept. de Ingenieria Quimica, Buenos Aires (Argentina)

    2009-07-01

    The production of {sup 48}V in a nuclear reactor, induced on titanium by tritons generated from the {sup 6}Li(n, t){sup 4} He reaction, and eventually {sup 7}Li(n, n't){sup 4}He, is described. Samples of lithium titanate were irradiated for an irradiation cycle (120 h) in the RA-3 reactor, belonging to Ezeiza Atomic Centre. After a radiochemical separation, the characteristic radiations from {sup 48}V were identified in the gamma ray spectra of the vanadium fractions. (orig.)

  15. Dissociation Energies of Diatomic Molecules

    Institute of Scientific and Technical Information of China (English)

    FAN Qun-Chao; SUN Wei-Guo

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7LID, 7LiH, 6LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy-Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies Detheory, which are in excellent agreement with the experimental dissociation energies Dexpte.

  16. Lithium isotope fractionation in the Ganges-Brahmaputra floodplain and implications for groundwater impact on seawater isotopic composition

    Science.gov (United States)

    Bagard, Marie-Laure; West, A. Joshua; Newman, Karla; Basu, Asish R.

    2015-12-01

    Lithium isotopes are a promising proxy for reconstructing past weathering processes, but unraveling the seawater record requires a comprehensive understanding of the magnitude and isotopic composition of Li fluxes to the oceans, and of how these change over time. Little information is available on the role of floodplain sediments and groundwater systems in setting the Li isotope signature of the dissolved flux delivered from the continents to the oceans. Here we investigate the Li dissolved fluxes of river waters and groundwaters in the Ganges-Brahmaputra floodplain. The data suggest that a maximum of 3.1 ×108 and 1.5 ×108 moles Li/yr are carried to the Bay of Bengal by Ganges-Brahmaputra rivers and groundwaters, respectively. The riverine flux has a significantly heavier Li isotope composition (average δ7Li: 26‰) than the groundwater flux (average δ7Li: 16‰) and increases downstream across the floodplain. δ7Li in both river waters and shallow groundwater can be explained by Li scavenging by Quaternary floodplain sediments following a Rayleigh fractionation process, with preferential removal of 6Li. On the other hand, deep groundwaters (>40 m) contributing to submarine groundwater discharge to the Bay of Bengal are enriched in 6Li at depth, likely due to the dissolution of floodplain sediments releasing Li with a light isotope composition. Similarly low δ7Li has been reported in other large sedimentary aquifers. The deep groundwater values are close to the average isotope composition of the global Li inputs to the ocean (∼15‰), so groundwater submarine discharge has only a minor influence on the assessment of the modern Li isotope budget of the ocean. Our analysis further suggests that groundwater discharge of Li has probably played at most a small and secondary role in past changes in the isotope composition of the total continental flux of Li to the ocean.

  17. 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...

  18. Note: Light output enhanced fast response and low afterglow 6Li glass scintillator as potential down-scattered neutron diagnostics for inertial confinement fusion

    International Nuclear Information System (INIS)

    The characteristics of an APLF80+3Ce scintillator are presented. Its sufficiently fast decay profile, low afterglow, and an improved light output compared to the recently developed APLF80+3Pr, were experimentally demonstrated. This scintillator material holds promise for applications in neutron imaging diagnostics at the energy regions of 0.27 MeV of DD fusion down-scattered neutron peak at the world's largest inertial confinement fusion facilities such as the National Ignition Facility and the Laser Megajoule.

  19. A universal, post Big-Bang Nucleo-synthesis, pre-Galactic, origin of the Lithium (Spite) Plateau

    CERN Document Server

    Ouyed, Rachid

    2012-01-01

    (Abridged abstract) We investigate the lithium plateau in the context of primordial dual-shock quark novae (dsQNe; i.e. a QN occurring a few days to a few weeks following the preceding SN explosion) going off in the wake of Pop. III stars. The neutron-rich relativistic QN ejecta leads to spallation of 56Ni processed in the ejecta of the preceding SN ejecta and thus to "iron impoverishment" of the primordial gas swept by dsQNe. We show that the generation of stars formed from fragmentation of pristine clouds swept-up by dsQNe acquire a metallicity with -7.5 2 (and up to [C/Fe] ~ 5) can be accounted for in our model for dsQNe with t_delay 10-11 days (i.e. [Fe/H] > -3). For shorter delays the temperature of the SN shell is too hot (> 2.5x10^6 K) for the spallated 7Li to survive. We find a corresponding 6Li plateau with 6Li/7Li < 0.3.

  20. Liquid-liquid extraction to lithium isotope separation based on room-temperature ionic liquids containing 2,2'-binaphthyldiyl-17-crown-5

    International Nuclear Information System (INIS)

    A novel liquid-liquid extraction system was investigated for the selective separation of lithium isotopes using ionic liquids (ILs = C8mim+PF6-, C8mim+BF4-, and C8mim+NTf2-) as extraction solvent and 2,2'-binaphthyldiyl-17-crown-5 (BN-17-5) as extractant. The effects of the concentration of lithium salt, counter anion of lithium salt, initial pH of aqueous phase, extraction temperature, and time on the lithium isotopes separation were discussed. Under optimized conditions, the maximum single-stage separation factor α of 6Li/7Li obtained in the present study was 1.046 ± 0.002, indicating the lighter isotope 6Li was enriched in IL phase while the heavier isotope 7Li was concentrated in the solution phase. The formation of 1:1 complex Li(BN-17-5)+ in the IL phase was determined on the basis of slope analysis method. The large value of the free energy change (-ΔG° = 92.89 J mol-1) indicated the high separation capability of the Li isotopes by BN-17-5/IL system. Lithium in Li(BN-17-5)+ complex was stripped by 1 mol L-1 HCl solution. The extraction system offers high efficiency, simplicity, and green application prospect to lithium isotope separation. (author)

  1. Mixtures of ultracold gases: Fermi sea and Bose-Einstein condensate of lithium isotopes

    Science.gov (United States)

    Schreck, F.

    2003-03-01

    This thesis presents studies of quantum degenerate atomic gases of fermionic ^6Li and bosonic ^7Li. Degeneracy is reached by evaporative cooling of ^7Li in a strongly confining magnetic trap. Since at low temperatures direct evaporative cooling is not possible for a polarized fermionic gas, ^6Li is sympathetically cooled by thermal contact with ^7Li. In a first series of experiments both isotopes are trapped in their low-field seeking higher hyperfine states. A Fermi degeneracy of T/T_F=0.25(5) is achieved for 10^5 fermions. For more than 300 atoms, the ^7Li condensate collapses, due to the attractive interatomic interaction in this state. This limits the degeneracy reached for both species. To overcome this limit, in a second series of experiments ^7Li and ^6Li atoms are transferred to their low field seeking lower hyperfine states, where the boson-boson interaction is repulsive but weak. The inter-isotope collisions are used to thermalize the mixture. A ^7Li Bose-Einstein condensate (BEC) of 10^4 atoms immersed in a Fermi sea is produced. The BEC is quasi-one-dimensional and the thermal fraction can be negligible. The measured degeneracies are T/T_C=T/T_F=0.2(1). The temperature is measured using the bosonic thermal fraction, which vanishes at the lowest temperatures, limiting our measurement sensitivity. In a third series of experiments, the bosons are transferred into an optical trap and their internal state is changed to |F=1,m_F=1rangle, the lowest energy state. A Feshbach resonance is detected and used to produce a BEC with tunable atomic interactions. When the effective interaction between atoms is tuned to be small and attractive, we observe the formation of a matter-wave bright soliton. Propagation of the soliton without spreading over a macroscopic distance of 1.1 mm is observed. Mélanges de gaz ultrafroids: mer de Fermi et condensat de Bose-Einstein des isotopes du lithium Cette thèse décrit l'étude des gaz de fermions ^6Li et de bosons ^7Li dans le

  2. Toward a self-consistent and unitary reaction network for big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Unitarity, the mathematical expression of the conservation of probability in multichannel reactions, is an essential ingredient in the development of accurate nuclear reaction networks appropriate for nucleosynthesis in a variety of environments. We describe our ongoing program to develop a 'unitary reaction network' for the big-bang nucleosynthesis environment and look at an example of the need and power of unitary parametrizations of nuclear scattering and reaction data. Recent attention has been focused on the possible role of the 9B compound nuclear system in the resonant destruction of 7Li during primordial nucleosynthesis. We have studied reactions in the 9B compound system with a multichannel, two-body unitary R-matrix code (EDA) using the known elastic and reaction data, in a four-channel treatment. The data include elastic 6Li(3He,3He)6Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for 6Li(3He,p)8Be* and from 0.4 to 5.0 MeV for the 6Li(3He,γ)7Be reaction. Capture data have been added to the previous analysis with integrated cross section measurements from 0.7 to 0.825 MeV for 6Li(3He,γ)9B. The resulting resonance parameters are compared with tabulated values from TUNL Nuclear Data Group analyses. Previously unidentified resonances are noted and the relevance of this analysis and a unitary reaction network for big-bang nucleosynthesis are emphasized. (author)

  3. Toward a self-consistent and unitary reaction network for big-bang nucleosynthesis

    Directory of Open Access Journals (Sweden)

    Paris Mark W.

    2014-04-01

    Full Text Available Unitarity, the mathematical expression of the conservation of probability in multichannel reactions, is an essential ingredient in the development of accurate nuclear reaction networks appropriate for nucleosynthesis in a variety of environments. We describe our ongoing program to develop a “unitary reaction network” for the big-bang nucleosynthesis environment and look at an example of the need and power of unitary parametrizations of nuclear scattering and reaction data. Recent attention has been focused on the possible role of the 9B compound nuclear system in the resonant destruction of 7Li during primordial nucleosynthesis. We have studied reactions in the 9B compound system with a multichannel, two-body unitary R-matrix code (EDA using the known elastic and reaction data, in a four-channel treatment. The data include elastic 6Li(3He,3He6Li differential cross sections from 0.7 to 2.0 MeV, integrated reaction cross sections for energies from 0.7 to 5.0 MeV for 6Li(3He,p8Be* and from 0.4 to 5.0 MeV for the 6Li(3He,d7Be reaction. Capture data have been added to the previous analysis with integrated cross section measurements from 0.7 to 0.825 MeV for 6Li(3He,γ9B. The resulting resonance parameters are compared with tabulated values from TUNL Nuclear Data Group analyses. Previously unidentified resonances are noted and the relevance of this analysis and a unitary reaction network for big-bang nucleosynthesis are emphasized.

  4. Investigation of neutron converters for production of optically stimulated luminescence (OSL) neutron dosimeters using Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Mittani, J.C.R. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Silva, A.A.R. da [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States); Vanhavere, F. [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium); Akselrod, M.S. [Landauer, Inc., Stillwater Crystal Growth Division, 723 1/2 Eastgate Rd., Stillwater, OK 74074 (United States); Yukihara, E.G. [Department of Physics, Oklahoma State University, Stillwater, OK 74078-3072 (United States)]. E-mail: eduardo.yukihara@okstate.edu

    2007-07-15

    This paper presents the optically stimulated luminescence (OSL) properties of neutron dosimeters in powder and in the form of pellets prepared with a mixture of Al{sub 2}O{sub 3}:C and neutron converters. The neutron converters investigated were high density polyethylene (HDPE), lithium fluoride (LiF), lithium fluoride 95% enriched with {sup 6}Li ({sup 6}LiF), lithium carbonate 95% enriched with {sup 6}Li ({sup 6}Li{sub 2}CO{sub 3}), boric acid enriched with 99% of {sup 10}B (H{sub 3}{sup 10}BO{sub 3}) and gadolinium oxide (Gd{sub 2}O{sub 3}). The proportion of Al{sub 2}O{sub 3}:C and neutron converter in the mixture was varied to optimize the total OSL signal and neutron sensitivity. The neutron sensitivity and dose-response were determined for the OSL dosimeters using a bare {sup 252}Cf source and compared to the response of Harshaw TLD-600 and TLD-700 dosimeters ({sup 6}LiF:Mg,Ti and {sup 7}LiF:Mg,Ti). The results demonstrate the possibility of developing an OSL dosimeter made of Al{sub 2}O{sub 3}:C powder and neutron converter with a neutron sensitivity (defined as the ratio between the {sup 60}Co equivalent gamma dose and the reference neutron absorbed dose) and neutron-gamma discrimination comparable to the TLD-600/TLD-700 combination. It was shown that the shape of the OSL decay curves varied with the type of the neutron converter, demonstrating the influence of the energy deposition mechanism and ionization density on the OSL process in Al{sub 2}O{sub 3}:C.

  5. Production of monoenergetic neutrons with energies between a few hundred keV and 40 MeV

    International Nuclear Information System (INIS)

    Various modes of production of monoenergetic neutrons with energies between a few hundred keV and 40 MeV are presented. Required characteristics for the neutron sources, source reactions - 7Li+p, 3H+p, 2H+d, 3H+d, 9Be+p - and targets are described

  6. Assessing Silicate Weathering in Permafrost-Dominated Catchments Using Lithium Isotopes: The Lena River, Siberia

    Science.gov (United States)

    Murphy, M. J.; Pogge von Strandmann, P.; Porcelli, D.; Katchinoff, J. A.; Moreras Martí, A.; Hirst, C. A.; Andersson, P. S.; Maximov, T. C.

    2015-12-01

    Rising global temperatures have the potential to influence the Earth's climate feedback cycles due to permafrost thawing, altering the freshwater input and trace metal and carbon fluxes into the ocean and atmosphere. Riverine lithium isotope ratios (d7Li) are a tracer of silicate weathering processes, which are key in the removal of atmospheric CO2 over geological timescales. Despite this, little is known about the effects of permafrost thawing on d7Li variations. Strong seasonal changes in the thawed active layer thickness dictate surficial water flow paths, which may influence intra-annual riverine d7Li signatures. We present a study of the dissolved d7Li from the large permafrost-dominated watersheds of the Lena River (Siberia), which drain into the Arctic Ocean. This work comprises a temporal study during the May 2015 spring flood, from ice breakup through peak flooding, thus monitoring changes in water-rock and water-soil interaction, both processes that control weathering and hence Li isotopes. Before riverine ice started to break up, high [Li] are observed as the river signature is governed by winter base flow conditions. As the river ice breaks up, surface runoff flows over the impermeable permafrost, interacting with leaf litter, diluting the [Li]. We compare d7Li over the spring flood period with a greater spatial study conducted over two summer field seasons (2012/2013) of the main Lena River channel and its tributaries, which drain a variety of lithologies/topographies. During the summer, the thawed active layer promotes deeper water flow paths, greater water-rock interaction and enhanced secondary minerals formation which preferentially take up 6Li. Summer riverine d7Li typically fall between +14.5 ‰ to +28.5 ‰, with rivers draining the Central Siberian Plateau typically exhibiting high [Li], but similar δ7Li to rivers draining the Verkhoyansk Mountain Range. Overall, this study demonstrates how Li isotopes respond to weathering in a permafrost

  7. Theoretical studies of 8He β-decay

    Science.gov (United States)

    Grigorenko, L. V.; Shul'gina, N. B.; Zhukov, M. V.

    1996-02-01

    According to selection rules the β-decay of 8He 0 g.s.+ to the first excited 1 +, 0.98 MeV state of 8Li is an allowed Gamow-Teller transition, but it is strongly suppressed by the different SU(4) spin-isospin structure of the 8He and 8Li states. We find that a three-body α + t + n model of 8Li strongly underestimates the probability for β-decay (to the 8Li (0.98) state, 7Li + n continuum and α + t + n continuum). A qualitative explanation of total BGT values, extracted from experiment, to different 1 + states can be given supposing an admixture of a "democratic" α + 4N configuration in the 8Li wave functions. We show that the experimental β-delayed neutron spectrum provides some evidence for the existence of 1 - and/or 2 - states in the vicinity of the two-body 7Li + n and 7Li ∗(0.47) + n thresholds. Using the phase volume approximation to the analysis of the triton spectrum, the position of the Gamow-Teller resonance (Halo Analogue state) is estimated between 8.5 and 8.8 MeV excitation energy in the 8Li spectrum. One of the possibilities to excite this state could be the 6Li( 6He,α) 8He ∗ reaction.

  8. Peripheral photon and neutron doses from prostate cancer external beam irradiation.

    Science.gov (United States)

    Bezak, Eva; Takam, Rundgham; Marcu, Loredana G

    2015-12-01

    Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose. PMID:25564673

  9. Optical Potential Parameters for Halo Nucleus System 6He+12C From Transfer Reaction 11B(7Li,6He)12C

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>The optical potential parameter is one of the most important quantities, which is closely related to the internal structure of the colliding nuclei. 6He is a well-known neutron-halo nucleus which can be

  10. Verification test for three WindCube WLS7 LiDARs at the Høvsøre test site

    DEFF Research Database (Denmark)

    Gottschall, Julia; Courtney, Michael

    The report describes the procedure of testing ground-based WindCube lidars (manufactured by the French company Leosphere) at the Høvsøre test site in comparison to reference sensors mounted at a meteorological mast. Results are presented for three tested units – in detail for unit WLS7-0062, and ......-0062, and in a summary for units WLS7-0064 and WLS7-0066. The verification test covers the evaluation of measured mean wind speeds, wind directions and wind speed standard deviations. The data analysis is basically performed in terms of different kinds of regression analyses....

  11. Spectator invariance test in the study of the Trojan Horse Method 6,7Li fusion reactions via the Trojan Horse Method

    OpenAIRE

    Li C; La Cognata M.; Kroha V.; Kiss G.G.; Hons Z.; Cherubini S.; Burjan V.; Blokhintsev L.; Spitaleri C.; Mukhamedzhanov A.; Bertulani C.; Lamia L.; Pizzone R.G.; Mrazek J.; Piskoř S.

    2011-01-01

    Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even sometimes impossible. In such cases the use of indirect methods can give a substantial help. The Trojan Horse Method (THM) is based on the quasi-free break-up of a nucleus, which can be described in terms of a cluster structure. In such applications the independence of THM results with differe...

  12. Multinucleon transfer reactions

    International Nuclear Information System (INIS)

    Nuclear reactions induced by complex nuclei are studied. The description of the single neutron transfer is used to show some aspect of the theoretical treatment of transfer reactions and rules concerning the dependence of cross sections on quantum numbers of the initial and final channels are deduced. Strongly excited states of 20Ne, 19F, sup(16,17)0, 15N were studied experimentally by using different projectile-target combinations in the four-particle, eight-particle and ten-particle transfer reactions, leading to the some final nuclei. Obtained results are discussed. In addition, studies of the projectile break-up phenomenon were performed. The dissociation of 6Li and 7Li projectiles was investigated in reactions on Pb, Sn and Ni nuclei. These nuclei were chosen to allow measurements at one incident energy below, above and at the Coulomb barrier. The observed spectra indicate that the process proceeds primarily via the resonance level but the shape deviates from the shape which was calculated assuming isotropic decay of the excited 6Li in its center of mass system. The investigations of the elastic scattering turned out to be more fruitful and allowed to define better the Coulomb barrier for the 6Li-target system. (S.B.)

  13. Lithium loaded glass detectors for tritium breeding measurements

    International Nuclear Information System (INIS)

    A technique based on the response differences of enriched 6Li and 7Li glass scintillators has been developed for the real time measurement of the tritium production rate from the 6Li isotope in an experimental breeder blanket of a D-T fusion reactor. The effectiveness of the method is dependent on the degree to which the scintillation responses of two glasses can be matched for all interactions arising from the neutron and gamma fields within the assembly. However, the energy resolution of the scintillation pulses contains a component that is dependent on the composition of the glass which cannot be compensated for either electronically or analytically. The glasses used must therefore be carefully selected to ensure that the difference between their intrinsic scintillation resolutions is minimal. This paper describes measurements of the scintillation energy resolution for a range of commerically available glasses as a function of energy for electrons, protons, deuterons, and alpha particles. The results showed that systematic errors in the measurement of tritium breeding from 6Li, using the proposed technique, are minimized if the glasses of different lithium enrichment have the same chemical composition. Analysis of the results indicated that for optimum accuracy the total lithium content of the glasses should be small (about 2%). (orig.)

  14. 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.

  15. Complete determination of neutron yield from 62 MeV protons on 9Be for the design of a low – power ADS

    Directory of Open Access Journals (Sweden)

    Schillaci Maria

    2014-03-01

    Full Text Available Within the European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics of future fast neutron-based reactors are very important. In this respect, an Accelerator Driven System low-power prototype, based on a 70 MeV proton beam impinging on a thick Beryllium converter, was recently proposed and designed within the INFN-E project. The world data on neutron yield from Be target are scarce in this proton energy range. This lack of data calls for a dedicated measurement which was performed at INFN Laboratori Nazionali del Sud, covering a wide angular range, from 0 to 150 degrees, and an almost complete neutron energy interval, from thermal up to the beam energy. In this contribution the results are discussed together with the description of the proposed ADS facility.

  16. Fast-neutron-spectrum measurements for the thick-target 9Be(d,n)10B reaction at E/sub d/ = 7 MeV

    International Nuclear Information System (INIS)

    Spectra of neutrons with energies greater than or equal to 800 keV which are emitted from a metallic beryllium target that is thick enough to completely stop 7-MeV incident deuterons are measured using organic scintillators and the pulse-beam time-of-flight method. Data are acquired for twenty different emission angles in the laboratory over the range 0 to 155 degrees. The resulting information on the energy-angle detail of neutron emission is then employed in calculations which are performed in order to examine certain effects of the anisotropic neutron production on typical measurements of integral fast-neutron reaction cross sections. 28 refs

  17. Development and application of the electrochemical etching technique

    International Nuclear Information System (INIS)

    This report documents the advances achieved in the development and application of several etched damage track plastic dosimeters that can be used to measure dose-equivalent from neutrons with energies from thermal to 20 MeV. The project was initiated with the design of a rem-responding dosimeter that measured fast (> 1 MeV) neutron dose-equivalent as a function of the damage track density directly induced within the volume of polycarbonate foils amplified by electrochemical etching. Stillwagon (1978) adapted electrochemical etching of polycarbonate foils (ECEPF) to alpha dosimetry and used the technique to determine Pu-239 uptake in human bone. Su (1979) extended the usefulness of the ECEPF neutron dosimetry technique to encompass thermal neutron dose measurement. The thermal neutron dosimeter was composed of an external radiator tablet made of 7LiF in contact with a polycarbonate foil and utilized the thermal neutron-induced 6Li(n, α)3H reaction to give a dose-equivalent response as a function of alpha track density registered in the detector foil. An intermediate (1 eV-1 MeV) neutron dosimeter was developed and has been shown to give an approximately dose-equivalent response to neutrons with energies from 1 eV to 17 MeV. The intermediate neutron dosimeter consists of 6LiF-Teflon/CR-39 Polymer foil assembly which is enclosed by a (Cd + In) neutron filter. The neutron dose-equivalent is measured as a variable function of the damage track density registered in the CR-39 detector foil due to alpha particles from the 1/v dependent 6Li(n, α)3H reaction, recoil H, C, O nuclei from neutron-induced elastic scattering within the foil volume, and protons from the 6Li(n, p) reaction for neutron energies above 2 MeV. 46 figs., 6 tabs

  18. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    Science.gov (United States)

    Banerjee, Projjwal; Qian, Yong-Zhong; Heger, Alexander; Haxton, Wick

    2016-02-01

    We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10-3 Z⊙. We find that for progenitors of ˜ 11-15 M⊙, the neutrons released by 4He(accent="true">ν¯ee, e+n)3H in He shells can be captured to produce nuclei with mass numbers up to A ˜ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ)8Li(n,γ)9Li(e- accent="true">ν¯ee)9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ˜ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n0)9Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  19. Tritium breeding mock-up experiments containing lithium titanate ceramic pebbles and lead irradiated with DT neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Jakhar, Shrichand; Abhangi, M.; Tiwari, S. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Makwana, R. [Department of Physics, MS University, Vadodara (India); Chaudhari, V.; Swami, H.L.; Danani, C.; Rao, C.V.S.; Basu, T.K. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Mandal, D.; Bhade, Sonali; Kolekar, R.V.; Reddy, P.J. [Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Bhattacharyay, R.; Chaudhuri, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2015-06-15

    Highlights: • Breeding benchmark experiment on LLCB TBM in ITER was performed. • Nuclear responses measured are TPR and reaction rate of {sup 115}In(n, n′){sup 115m}In reaction. • Measured responses are compared with calculations by MCNP and FENDL 2.1 library. • TPR measurements agree with calculations in the estimated error bar. • Measured {sup 115}In(n, n′){sup 115m}In reaction rates are underestimated by the calculations. - Abstract: Experiments were conducted with breeding blanket mock-up consisting of two layers of breeder material lithium titanate pebbles and three layers of pure lead as neutron multiplier. The radial dimensions of breeder, neutron multiplier and structural material layers are similar to the current design of the Indian Lead–Lithium cooled Ceramic Breeder (LLCB) blanket. The mock-up assembly was irradiated with 14 MeV neutrons from DT neutron generator. The local tritium production rates (TPR) from {sup 6}Li and {sup 7}Li in breeder layers were measured with the help of two different compositions of Li isotopes (60.69% {sup 6}Li and 7.54% {sup 6}Li) in Li{sub 2}CO{sub 3}. Tritium production in the multiplication layers were also measured with above mentioned two types of pellets to compare the experimental tritium production with calculations. TPR from {sup 6}Li at one location in the breeder layer was also measured by direct online measurement of tritons from {sup 6}Li(n, t){sup 4}He reaction using silicon surface barrier detector and {sup 6}Li to triton converter. Additional verification of neutron spectra (E{sub n} > 0.35 MeV) in the mock-up zones were obtained by measuring {sup 115}In(n, n′){sup 115m}In reaction rate and comparing it with calculated values in all five layers of mock-up. All the measured nuclear responses were compared with transport calculations using code MCNP with FENDL2.1 and FENDL3.0 cross-section libraries. The average C/E ratio for tritium production in enriched Li{sub 2}CO{sub 3} pellets was 1

  20. Deuteron-induced nucleon transfer reactions within an ab initio framework: First application to p -shell nuclei

    Science.gov (United States)

    Raimondi, Francesco; Hupin, Guillaume; Navrátil, Petr; Quaglioni, Sofia

    2016-05-01

    Background: Low-energy transfer reactions in which a proton is stripped from a deuteron projectile and dropped into a target play a crucial role in the formation of nuclei in both primordial and stellar nucleosynthesis, as well as in the study of exotic nuclei using radioactive beam facilities and inverse kinematics. Ab initio approaches have been successfully applied to describe the 3H (d ,n )4He and 3He(d ,p )4He fusion processes. Purpose: An ab initio treatment of transfer reactions would also be desirable for heavier targets. In this work, we extend the ab initio description of (d ,p ) reactions to processes with light p -shell nuclei. As a first application, we study the elastic scattering of deuterium on 7Li and the 7Li(d ,p )8Li transfer reaction based on a two-body Hamiltonian. Methods: We use the no-core shell model to compute the wave functions of the nuclei involved in the reaction, and describe the dynamics between targets and projectiles with the help of microscopic-cluster states in the spirit of the resonating group method. Results: The shapes of the excitation functions for deuterons impinging on 7Li are qualitatively reproduced up to the deuteron breakup energy. The interplay between d -7Li and p -8Li particle-decay channels determines some features of the 9Be spectrum above the d +7Li threshold. Our prediction for the parity of the 17.298 MeV resonance is at odds with the experimental assignment. Conclusions: Deuteron stripping reactions with p -shell targets can now be computed ab initio, but calculations are very demanding. A quantitative description of the 7Li(d ,p )8Li reaction will require further work to include the effect of three-nucleon forces and additional decay channels and to improve the convergence rate of our calculations.

  1. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    Directory of Open Access Journals (Sweden)

    Banerjee Projjwal

    2016-01-01

    Full Text Available We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10−3 Z⊙. We find that for progenitors of ∼ 11–15 M⊙, the neutrons released by 4He(ν¯ee, e+n3H in He shells can be captured to produce nuclei with mass numbers up to A ∼ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ8Li(n,γ9Li(e− ν¯ee9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ∼ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n09Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  2. Multiheteromacrocycles that Complex Metal Ions. Sixth Progress Report, 1 May 1979-30 April 1980

    Science.gov (United States)

    Cram, D. J.

    1980-01-15

    Objective is to design synthesize, and evaluate cyclic and polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions, their complexes, and their clusters. Host organic compounds consist of strategically placed solvating, coordinating, and ion-pairing sites tied together by covalent bonds through hydrocarbon units around cavities shaped to be occupied by guest metal ions or by metal ions plus their ligands. Specificity in complexation is sought by matching the following properties of host and guest: cavity and metal ion sizes; geometric arrangements of binding sites; number of binding sites; character of binding sites; and valences. During this period, hemispherands based on an aryloxy or cyclic urea unit, spherands based on aryloxyl units only, and their complexes with alkali metals and alkaline earths were investigated. An attempt to separate {sup 6}Li and {sup 7}Li by gel permeation chromatography of lithiospherium chloride failed. (DLC)

  3. Carbon isotopic composition effects on interatomic interactions and the properties of diamond

    International Nuclear Information System (INIS)

    The interatomic interaction potential parameters were determined for 12C and 13C in diamond. The results were used to obtain the isotopic dependences of such diamond properties as the Debye temperature, molar heat capacity, thermal expansion coefficient, energies of vacancy formation and self-diffusion, surface energy, and longitudinal velocity of sound. The isotopic dependence of isochoric heat capacity disappeared as the temperature increased. Sign inversion was observed for the isotopic dependence of the thermal expansion coefficient at a certain temperature: its growth changed into a drop. This approach was also used to estimate changes in the interatomic interaction potential and crystal bulk compression modulus of lithium in going from 7Li to 6Li. The isotopic dependences of phase transition parameters and the whole p-T phase diagram of a simple substance were predicted

  4. Use of thermoluminescent dosimeters for measurement of fast-neutron spatial-distribution at the plasma focus device PF-1000

    International Nuclear Information System (INIS)

    A system of moderators of DD-fusion neutrons emitted by the plasma focus device PF-1000 at IPPLM, Warsaw was employed for the use of thermoluminescent dosimeters (TLDs) as passive detectors of thermal neutrons. The diagnostics was derived from Monte Carlo calculations of responses of dosimeters located in spherical polyethylene moderators with different diameters. As time-integrating dosimeters coupled 6LiF:Mg,Cu,P (TLD-600H) and 7LiF:Mg,Cu,P (TLD-700H) detectors were applied. A difference in read-out signals between TLD-600H and TLD-700H dosimeters, which is directly proportional to the number of thermal neutron interactions, is compared with the response of silver activation detectors. The detectors used started to operate from a neutron yield of ∼5x109 and present a convenient method for investigation of spatial-distribution of neutron emission

  5. Development of Tritium Permeation Analysis Code and Tritium Transport in a High Temperature Gas-Cooled Reactor Coupled with Hydrogen Production System

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh; Eung S. Kim; Mike Patterson

    2010-06-01

    Abstract – A tritium permeation analyses code (TPAC) was developed by Idaho National Laboratory for the purpose of analyzing tritium distributions in very high temperature reactor (VHTR) systems, including integrated hydrogen production systems. A MATLAB SIMULINK software package was used in developing the code. The TPAC is based on the mass balance equations of tritium-containing species and various forms of hydrogen coupled with a variety of tritium sources, sinks, and permeation models. In the TPAC, ternary fission and neutron reactions with 6Li, 7Li 10B, and 3He were taken into considerations as tritium sources. Purification and leakage models were implemented as main tritium sinks. Permeation of tritium and H2 through pipes, vessels, and heat exchangers were considered as main tritium transport paths. In addition, electroyzer and isotope exchange models were developed for analyzing hydrogen production systems, including high temperature electrolysis and sulfur-iodine processes.

  6. Study of performance of a dosemeter based on thermoluminescent materials for external personnel monitoring

    International Nuclear Information System (INIS)

    The performance of a dosemeter based on thermoluminescent materials, 7 LiF and 6 LiF, was investigated. The verification if the dosemeter response complies with tests recommended by national and international regulatory organizations was performed. Tests of angular and energy dependence, reproducibility, detectability threshold, batch homogeneity and others were carried out and the obtained response is herein presented. Dosemeter response was evaluated in terms of Hp(10). The tests were carried out taking into account the IRD-RT No 001.01/95 and IEC 1066 reporters that gave the guidelines for this evaluation. The obtained response showed that the studied dosemeter complies with the tests and can be employed for individual monitoring. (author)

  7. Determination of Energy and Angular Response of an Albedo Neutron Personal Dosemeter

    International Nuclear Information System (INIS)

    The result of the determination of energy and angular response for the albedo neutron personal dosemeter used by CPHR, is described. The dosemeters consist of two pairs of LiF detectors (6LiF+7LiF) separated by a piece of boron-loaded plastic. For the study, the dosemeters were irradiated in three mixed neutron-gamma fields (thermal neutrons, moderated 241Am-Be and 241Am-Be) and at two incidence angles of radiation (0 deg. and 60 deg. ). The variation of the sensibility at different neutron spectra and incidence angles of radiation was determined. The methodology of dose evaluation, applying the obtained coefficients, was established. (author)

  8. Isotope ratio determination of lithium in acidic medium employing Li2BO2+ by TIMS

    International Nuclear Information System (INIS)

    Lithium isotopic composition data are required in many fields such as geochemistry, astrophysics, nuclear technology and biomedicine. Thermal Ionization Mass Spectrometry and in the recent years, MC-ICPMS are the two popular techniques used for obtaining information on 6Li/7Li isotopic ratio. Isotopic fractionation, especially for elements of low atomic masses like lithium degrades the precision of isotope ratios. A number of approaches using atomic (Li+) or molecular (Li2BO2+ or Li2F+) ion, single or multiple filament loading procedures have been followed to improve the precision of TIMS analysis. Existing sample preparation and filament loading techniques require modification depending on the history of the sample or treatment procedures followed. Our laboratory has followed the Li2BO2+ method using single filament assembly due to the reasonably high precision obtained at masses 55 to 57 as compared to Li+ at masses 6 and 7

  9. Coulomb explosion of nanodroplets drives the conversion of laser energy to nuclear energy

    Institute of Scientific and Technical Information of China (English)

    Isidore; Last; Shlomo; Ron; Andreas; Heidenreich; Joshua; Jortner

    2013-01-01

    Theoretical–computational studies of table-top laser-driven nuclear fusion of high-energy(up to 15 MeV)deuterons with7Li,6Li,and D nuclei demonstrate the attainment of high fusion yields within a source–target reaction design.This constitutes a source of Coulomb-exploding deuterium nanodroplets driven by an ultraintense femtosecond near-infrared laser and a solid hollow cylindrical target containing the second element.The source–target reaction design attains the highest table-top fusion efficiencies(up to 4×109J 1per laser pulse)obtained to date.The highest conversion efficiency of laser energy to nuclear energy(10 2–10 3)for table-top DD fusion attained in the source–target design is comparable to that for DT fusion currently accomplished for‘big science’inertial fusion setups.

  10. Protosolar Irradiation in the Early Solar System: Clues from Lithium and Boron Isotopes

    CERN Document Server

    Liu, Ming-Chang; Alexander, Conel M O'D; Lee, Typhoon

    2011-01-01

    We report Li and B isotopic compositions of 10 Spinel-HIBonite spherules (SHIBs) separated from the Murchison meteorite, in order to understand their irradiation history in the early Solar System. The extremely low Be concentrations in SHIBs preclude detection of extinct 10Be, but instead allow for a search of the original Li and B isotopic ratios of the grains, as these isotopes are sensitive indicators for irradiation. We found that some of the SHIBs carried sub-chondritic 7Li/6Li and supra-chondritic 10B/11B ratios. Considering two possible irradiation scenarios that could have occurred in the early Solar System, irradiation of hibonite solids followed by addition of isotopically normal Li and B seems to be the most plausible explanation for the observed Li and B isotope ratios.

  11. Production of beams from solid materials at Center for Nuclear Study electron cyclotron resonance ion source

    Science.gov (United States)

    Ohshiro, Y.; Yamaka, S.; Watanabe, S.; Kobayashi, K.; Kotaka, Y.; Nishimura, M.; Kase, M.; Muto, H.; Yamaguchi, H.; Shimoura, S.

    2014-02-01

    Two methods for the feed of vapor from solid materials in the Center for Nuclear Study ECR ion source are described. A rod placed near the wall of the plasma chamber, operating up to a melting point of 2600 °C, has been used for CaO, SiO2, and FeO. An oven with a number of openings, operating up to 800 °C, has been used for P2O5, Li, and S. Typical ion beam intensities of 7Li2+, 6Li3+, 40Ca12+, and 56Fe15+ are achieved 280, 75, 28, and 7 eμA, respectively. High intensity heavy ion beams are stably supplied into the azimuthally varying field cyclotron.

  12. Experimental differential cross sections, level densities, and spin cutoffs as a testing ground for nuclear reaction codes

    Science.gov (United States)

    Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Massey, T. N.; Siem, S.

    2013-11-01

    Proton double-differential cross sections from 59Co(α,p)62Ni, 57Fe(α,p)60Co, 56Fe(7Li,p)62Ni, and 55Mn(6Li,p)60Co reactions have been measured with 21-MeV α and 15-MeV lithium beams. Cross sections have been compared against calculations with the empire reaction code. Different input level density models have been tested. It was found that the Gilbert and Cameron [A. Gilbert and A. G. W. Cameron, Can. J. Phys.0008-420410.1139/p65-139 43, 1446 (1965)] level density model is best to reproduce experimental data. Level densities and spin cutoff parameters for 62Ni and 60Co above the excitation energy range of discrete levels (in continuum) have been obtained with a Monte Carlo technique. Excitation energy dependencies were found to be inconsistent with the Fermi-gas model.

  13. In-situ Isotopic Analysis at Nanoscale using Parallel Ion Electron Spectrometry: A Powerful New Paradigm for Correlative Microscopy

    Science.gov (United States)

    Yedra, Lluís; Eswara, Santhana; Dowsett, David; Wirtz, Tom

    2016-06-01

    Isotopic analysis is of paramount importance across the entire gamut of scientific research. To advance the frontiers of knowledge, a technique for nanoscale isotopic analysis is indispensable. Secondary Ion Mass Spectrometry (SIMS) is a well-established technique for analyzing isotopes, but its spatial-resolution is fundamentally limited. Transmission Electron Microscopy (TEM) is a well-known method for high-resolution imaging down to the atomic scale. However, isotopic analysis in TEM is not possible. Here, we introduce a powerful new paradigm for in-situ correlative microscopy called the Parallel Ion Electron Spectrometry by synergizing SIMS with TEM. We demonstrate this technique by distinguishing lithium carbonate nanoparticles according to the isotopic label of lithium, viz. 6Li and 7Li and imaging them at high-resolution by TEM, adding a new dimension to correlative microscopy.

  14. Comparative study between hadron and heavy ion dissociation at high energies

    International Nuclear Information System (INIS)

    The present work deals with the dissociation of hadrons and heavy ions at high energies. In investigating hadron nucleus and nucleus-nucleus collisions, it is important to classify the experimental data, into two main classes; the coherent. and incoherent reactions. The coherent production is the main of our study. This process called electromagnetic dissociation (ED) and can be differentiate into coulomb dissociation (CD) and diffraction dissociation (DD). This work explains the experimental data of collisions of hadrons K± (70 GeV/c) and π(340 Gc V/c) and heavy ions 6Li, 7Li, 12C and16O at Dubna energies (3-4.5 A GeV/c)with emulsion target, in the frame of some models and theories which describe the mechanism of ED dissociation

  15. Summary documentation of LASL nuclear data evaluations for ENDF/B-V

    Energy Technology Data Exchange (ETDEWEB)

    Young, P.G. (comp.)

    1979-01-01

    Summaries are presented of nuclear data evaluations performed at Los Alamos Scientific Laboratory (LASL) that will comprise part of Version V of the Evaluated Nuclear Data File, ENDF/B. A total of 18 general purpose evaluations of neutron-induced data are summarized, together with 6 summaries directed specifically at covariance data evaluations. The general purpose evaluation summaries cover the following isotopes: /sup 1 -3/H, /sup 3/ /sup 4/He, /sup 6/ /sup 7/Li, /sup 10/B, /sup 14/ /sup 15/N, /sup 16/O, /sup 27/Al, /sup 182/ /sup 183/ /sup 184/ /sup 186/W, /sup 233/U, and /sup 242/Pu. The covariance data summaries are given for /sup 1/H, /sup 6/Li, /sup 10/B, /sup 14/N, /sup 16/O, and /sup 27/Al. 28 figures.

  16. An On-Board TLD System for Dose Monitoring on the International Space Station

    Energy Technology Data Exchange (ETDEWEB)

    Apathy, I.; Deme, S.; Bodnar, L.; Csoeke, A.; Hejja, I

    1999-07-01

    This institute has developed and manufactured a series of thermoluminescence dosemeter (TLD) systems for spacecraft, consisting of a set of bulb dosemeters and a small, compact TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A new implementation of the system will be placed on several segments of the ISS as the contribution of Hungary to this international enterprise. The well proven CaSO{sub 4}:Dy dosemeters will be used for routine dosimetry of the astronauts and in biological experiments. The mean LET value will be measured by LiF dosemeters while doses caused by neutrons are planned to be determined by {sup 6}LiF/{sup 7}LiF dosemeter pairs and moderators. A detailed description of the system is given. (author)

  17. Ionic Debye Screening in Dense Liquid Plasmas Observed for Li+p,d Reactions with Liquid Li Target

    Institute of Scientific and Technical Information of China (English)

    J.Kasagi; H.Yonemura; Y.Toriyabe; A.Nakagawa; T.Sugawara; WANG Tie-shan

    2009-01-01

    Thick target yields of a particles emitted in the ~6Li(d,a)~4 He and ~7Li(p,a)~4 He reactions were measured for Li target in the solid and liquid phase.Observed reaction rates for the liquid Li are always larger than those for the solid.This suggests that the stopping power of hydrogen ion in the liquid Li metal might be smaller than in the solid.Using the empirically obtained stopping power for the liquid Li,we have deduced the screening potentials of the Li+p and Li+d reactions in both phases.The deduced screening potential for the liquid Li is about 500 eV larger than for the solid.This difference is attributed to the effect of liquefied Li~+ ions.It is concluded that the ionic screening is much stronger than the electronic screening in a low-temperature dense plasmas.

  18. Production of shower particles from various beam collisions with different emulsion targets

    CERN Document Server

    Elnagdy, M S

    2003-01-01

    The reaction cross sections for 4.5 A GeV/cP, d, sup 4 He, sup 6 He, sup 6 Li, sup 7 Li, sup 1 sup 2 C, sup 1 sup 6 C, sup 1 sup 6 O, sup 2 sup 4 Mg, sup 2 sup * Si and sup 3 sup 2 S beams with different chemical components of emulsion nuclei are studied with high statistics, and compared with the calculations according to Glauber model. The multiplicity distributions of shower produced particles from the interactions with light and heavy emulsion nuclei are analyzed in terms of the negative binomial and Poisson laws. Some of the present negative binomial parameters agree with the corresponding ones obtained from the propane bubble chamber.

  19. In-situ Isotopic Analysis at Nanoscale using Parallel Ion Electron Spectrometry: A Powerful New Paradigm for Correlative Microscopy

    Science.gov (United States)

    Yedra, Lluís; Eswara, Santhana; Dowsett, David; Wirtz, Tom

    2016-01-01

    Isotopic analysis is of paramount importance across the entire gamut of scientific research. To advance the frontiers of knowledge, a technique for nanoscale isotopic analysis is indispensable. Secondary Ion Mass Spectrometry (SIMS) is a well-established technique for analyzing isotopes, but its spatial-resolution is fundamentally limited. Transmission Electron Microscopy (TEM) is a well-known method for high-resolution imaging down to the atomic scale. However, isotopic analysis in TEM is not possible. Here, we introduce a powerful new paradigm for in-situ correlative microscopy called the Parallel Ion Electron Spectrometry by synergizing SIMS with TEM. We demonstrate this technique by distinguishing lithium carbonate nanoparticles according to the isotopic label of lithium, viz. 6Li and 7Li and imaging them at high-resolution by TEM, adding a new dimension to correlative microscopy. PMID:27350565

  20. 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.