Reaction theory for analysis of nuclear giant resonances production and decay processes

International Nuclear Information System (INIS)

Foglia, G.A.

1991-01-01

The existence of mixing parameters connected to the different decay forms of the giant resonances was theoretically justified, and their energy dependence determined as well using a reaction theory which treats in a consistent manner the giant multipolar resonances formation and their different decay modes. (L.C.J.A.)

Systematics of complex fragment emission from La induced reactions at E/A = 47 MeV

International Nuclear Information System (INIS)

Kehoe, W.L.; Mignerey, A.C.; Bradley, S.

1989-03-01

Complex fragment (Z > 2) emission was studied in the reverse kinematics reactions of 139 La on 27 Al and /sup nat./Cu at a bombarding energy of E/A = 47 MeV. Experimental results from inclusive and coincidence measurements for two- and three-fold complex fragments events are presented. Measured cross sections and Z 1 -Z 2 correlations show a predominately binary-decay process for the La + Al reaction, while the La + Cu reaction is dominated by multi-body decay. 18 refs., 9 figs., 1 tab

Light-Baryon Production in Binary $pd$ Annihilation Reactions at Rest

CERN Document Server

Denisov, O Yu; Balestra, F; Botta, E; Bressani, Tullio; Bussa, M P; Busso, L; Calvo, D; Cerello, P G; Costa, S; D'Isep, D; Fava, L; Feliciello, A; Ferrero, L; Filippi, A; Garfagnini, R; Grasso, A; Iazzi, F; Maggiora, A; Marcello, S; Minetti, B; Mirfakhraee, N; Panzarasa, A; Panzieri, D; Piragino, G; Tosello, F; Zosi, G; Alberico, V; Bertin, A; Bruschi, M; Capponi, M; D'Antone, I; De Castro, S; Ferretti, A; Galli, D; Giacobbe, B; Marconi, U; Piccinini, M; Poli, M; Semprini-Cesari, N; Spighi, R; Vecchi, S; Vagnoni, V M; Vigotti, F; Villa, M; Vitale, A; Zoccoli, A; Bianconi, A; Corradini, M; Lodi-Rizzini, E; Venturelli, L; Zenoni, A; Cicalò, C; Masoni, A; Mauro, S; Puddu, G; Serci, S; Temnikov, P P; Usai, G L; Gortchakov, O E; Prakhov, S N; Rozhdestvensky, A M; Sapozhnikov, M G; Tretyak, V I; Gianotti, P; Guaraldo, C; Lanaro, A; Lucherini, V; Nichitiu, F; Petrascu, C; Ableev, V G; Cavion, C; Gastaldi, Ugo; Lombardi, M; Maron, G; Vannucci, Luigi; Vedovato, G; Bendiscioli, G; Filippini, V; Fontana, A; Montagna, P; Rotondi, A; Salvini, P; Pauli, G; Tessaro, S; Santi, L

1999-01-01

We report the study of light baryon production in two-prong annihilation reactions due to antiprotons stopping in gaseous deuterium and detected by the OBELIX spectrometer (LEAR, CERN). A clear signal of the Delta (1232) production in binary reactions was found in both annihilation channels: pd to pi /sup -/ Delta /sup +/( Delta /sup +/ to pi /sup 0/p) and pd to pi /sup 0/ Delta /sup 0/( Delta /sup 0/ to pi /sup -/p). The annihilation probabilities for these reactions turned out to be Y=(1.01+or-0.08)*10/sup -5/ and Y= (1.12+or-0.20)*10/sup -5/, respectively. In addition, the annihilation probability for the prototype Pontecorvo reaction pd to pi /sup -/p was measured with the best world statistics: Y= (1.46+or-0.08)*10/sup -5/. (16 refs).

Fundamentals of nuclear science and engineering

CERN Document Server

Shultis, J Kenneth

2007-01-01

FUNDAMENTAL CONCEPTS Modern Units The Atom Chart of Nuclides MODERN PHYSICS CONCEPTS The Special Theory of Relativity Radiation as Waves and Particles Quantum Mechanics Derivation of Some Special Relativity Results Solutions to Schrodinger's Wave Equation ATOMIC/NUCLEAR MODELS Development of the Modern Atom Model Models of the Nucleus NUCLEAR ENERGETICS Binding Energy Nucleon Separation Energy Nuclear Reactions Examples of Binary Nuclear Reactions Q-Value for a Reaction Conservation of Charge and the Calculation of Q-values Q-Value for reactions Producing Excited Nuclei RADIOACTIVITY Overview Types of Radioactive Decay Radioactive Decay Diagrams Energetics of Radioactive Decay Characteristics of Radioactive Decay Decay Dynamics Naturally Occurring Radionuclides Radiodating Radioactive Decay Data BINARY NUCLEAR REACTIONS Types of Binary Reactions Kinematics of Binary Two-Product Nuclear Reactions Reaction Threshold Energy Applications of Binary Kinematics Reactions...

Binary non-additive hard sphere mixtures: fluid demixing, asymptotic decay of correlations and free fluid interfaces

International Nuclear Information System (INIS)

Hopkins, Paul; Schmidt, Matthias

2010-01-01

Using a fundamental measure density functional theory we investigate both bulk and inhomogeneous systems of the binary non-additive hard sphere model. For sufficiently large (positive) non-additivity the mixture phase separates into two fluid phases with different compositions. We calculate bulk fluid-fluid coexistence curves for a range of size ratios and non-additivity parameters and find that they compare well to simulation results from the literature. Using the Ornstein-Zernike equation, we investigate the asymptotic, r→∞, decay of the partial pair correlation functions, g ij (r). At low densities a structural crossover occurs in the asymptotic decay between two different damped oscillatory modes with different wavelengths corresponding to the two intra-species hard-core diameters. On approaching the fluid-fluid critical point there is a Fisher-Widom crossover from exponentially damped oscillatory to monotonic asymptotic decay. Using the density functional we calculate the density profiles for the planar free fluid-fluid interface between coexisting fluid phases. We show that the type of asymptotic decay of g ij (r) not only determines the asymptotic decay of the interface profiles, but is also relevant for intermediate and even short-ranged behaviour. We also determine the surface tension of the free fluid interface, finding that it increases with non-additivity, and that on approaching the critical point mean-field scaling holds.

Model for competitive binary and ternary ion-molecule reactions

International Nuclear Information System (INIS)

Herbst, E.

1985-01-01

A mechanism by which competitive binary and ternary ion-molecule reactions can occur is proposed. Calculations are undertaken for the specific system CH3(+) + NH3 + He which has been studied in the laboratory by Smith and Adams (1978), and the potential surface of which has been studied theoretically by Nobes and Radom (1983). It is shown that a potential-energy barrier in the exit channel prevents the rapid dissociation of collision complexes with large amounts of angular momentum and thereby allows collisional stabilization of the complexes. The calculated ternary-reaction rate coefficient is in good agreement with the experimental value, but a plot of the effective two-body rate coefficient of the ternary channel vs helium density does not quite show the observed saturation. 21 references

Radical Abstraction Reactions with Concerted Fragmentation in the Chain Decay of Nitroalkanes

Science.gov (United States)

Denisov, E. T.; Shestakov, A. F.

2018-05-01

Reactions of the type X• + HCR2CH2NO2 → XH + R2C=CH2 + N•O2 are exothermic, due to the breaking of weak C-N bonds and the formation of energy-intensive C=C bonds. Quantum chemistry calculations of the transition state using the reactions of Et• and EtO• with 2-nitrobutane shows that such reactions can be categorized as one-step, due to the extreme instability of the intermediate nitrobutyl radical toward decay with the formation of N•O2. Kinetic parameters that allow us to calculate the energy of activation and rate constant of such a reaction from its enthalpy are estimated using a model of intersecting parabolas. Enthalpies, energies of activation, and rate constants are calculated for a series of reactions with the participation of Et•, EtO•, RO•2, N•O2 radicals on the one hand and a series of nitroalkanes on the other. A new kinetic scheme of the chain decay of nitroalkanes with the participation of abstraction reactions with concerted fragmentation is proposed on the basis of the obtained data.

Alpha-decay within Feshbach theory of nuclear reactions

International Nuclear Information System (INIS)

Sandulescu, A.; Silisteanu, I.; Wunsch, R.

1977-01-01

In the frame of Feshbach theory of nuclear reactions the alpha-decay widths are determined by the alpha-daughter nucleus optical potential and by the formation factors. It is shown that the calculated absolute values of the alpha widths for Po light isotopes are in good agreement with experimental data, if the real part of the optical potential with the parameters fitted by the low energy α-scattering is used

Studies of heavy-ion reactions and transuranic nuclei

International Nuclear Information System (INIS)

Schroeder, W.U.; Huizenga, J.R.

1991-08-01

The development of the ''cold-fusion'' episode is reviewed. Ongoing studies of compound-nucleus formation and decay via the neutron multiplicity distribution confirm the validity of conventional statistical theory. The excitation energy partition in near-barrier damped 58 Ni + 208 Pb collisions is found to be largely independent of the direction of net mass transfer, supporting a diffusion-like nucleon-exchange mechanism. Exclusive experiments on the heavy reaction systems 197 Au + 208 Pb and 209 Bi + 136 Xe in the Fermi-energy domain have revealed important new insights into the reaction mechanism, which is found to be dominated by damped, binary processes. The effectiveness of the neutron multiplicity as an impact-parameter filter is demonstrated. It is shown that very-heavy-ion reactions lead to transient nuclear systems with temperatures in excess of τ = 6 MeV and transfer of large, aligned spins to reaction fragments. The first measurements of neutrons in coincidence with kinematically identified reaction fragments provide evidence for the binary, sequential character of dissipative collisions in the Fermi-energy domain. Also for the first time, a full event characterization was achieved for nuclear reactions in terms of neutrons and charged particles. Technical information on this experiment is provided. First results yield strong evidence for dominantly binary primary reaction dynamics of even highly dissipative 209 Bi + (28MeV/u) 136 Xe collisions, associated with several intermediate-mass fragments

Compound nuclei, binary decay, and multifragmentation in intermediate-energy heavy-ion reactions

International Nuclear Information System (INIS)

Moretto, L.G.; Wozniak, G.J.

1988-07-01

Hot compound nuclei, frequently produced in intermediate-energy reactions through a variety of processes, are shown to be an important and at times dominant source of complex fragments. 13 refs., 12 figs

Heavy ion collision dynamics of 10,11B+10,11B reactions

Directory of Open Access Journals (Sweden)

Singh BirBikram

2015-01-01

Full Text Available The dynamical cluster-decay model (DCM of Gupta and collaborators has been applied successfully to the decay of very-light (A ∼ 30, light (A ∼ 40−80, medium, heavy and super-heavy mass compound nuclei for their decay to light particles (evaporation residues, ER, fusion-fission (ff, and quasi-fission (qf depending on the reaction conditions. We intend to extend here the application of DCM to study the extreme case of decay of very-light nuclear systems 20,21,22Ne∗ formed in 10,11B+10,11B reactions, for which experimental data is available for their binary symmetric decay (BSD cross sections, i.e., σBSD. For the systems under study, the calculations are presented for the σBSD in terms of their preformation and barrier penetration probabilities P0 and P. Interesting results are that in the decay of such lighter systems there is a competing reaction mechanism (specifically, the deep inelastic orbiting of non-compound nucleus (nCN origin together with ff. We have emipirically estimated the contribution of σnCN. Moreover, the important role of nuclear structure characteristics via P0 as well as angular momentum ℓ in the reaction dynamics are explored in the study.

Multiparticle production in heavy-ion reactions

International Nuclear Information System (INIS)

Pelte, D.

1980-01-01

This lecture is concerned with the question how many particles and what kind of them are produced in heavy-ion collisions at energies about 10 MeV/n. We tend to assume that heavy-ion reactions at this energy are binary reactions. The experimental set consisting of two large ionization chambers serving to detection, in coincidence, the reaction fragments is described. With this set-up a number of reactions induced on 27 Al, 28 Si and 40 Ca by the 32 S beam of 135 and 190 MeV energy has been studied. Two-fragments inclusive and exclusive reactions were investigated. The assumption of a sequential statistical decay gives the best agreement with the data for all analyzed cases. (H.M.)

The systematics of the deexcitation of hot nuclei and the onset of multibody decay

International Nuclear Information System (INIS)

Bowman, D.R.; Peaslee, G.F.; Colonna, N.

1989-03-01

Results from the asymmetric reactions 80 and 100 MeV/uLa + C are presented and compared to earlier work with the same system at 18 and 50 MeV/u. Fragment-fragment correlations, cross sections, and distributions in velocity space indicate the continued dominance of a quasi-binary decay mechanism with increased emission of light charged particles. The distributions in velocity also indicate a progression toward a ''fireball'' type of reaction mechanism. However, the angular distributions of the emitted fragments are incompatible with statistical production mechanisms that have successfully explained the lower energy results, and indicate the dynamical nature of the emission process. Dalitz plots of triple complex fragment coincidences are presented in order to investigate the nature of the multibody decays. 18 refs., 9 figs

The decay of hot nuclei formed in La-induced reactions at E/A=45 MeV

International Nuclear Information System (INIS)

Libby, B.

1993-01-01

The decay of hot nuclei formed in the reactions 139 La + 27 Al, 51 V, nat Cu, and 139 La were studied by the coincident detection of up to four complex fragments (Z > 3) emitted in these reactions. Fragments were characterized as to their atomic number, energy and in- and out-of-plane angles. The probability of the decay by an event of a given complex fragment multiplicity as a function of excitation energy per nucleon of the source is nearly independent of the system studied. Additionally, there is no large increase in the proportion of multiple fragment events as the excitation energy of the source increases past 5 MeV/nucleon. This is at odds with many prompt multifragmentation models of nuclear decay. The reactions 139 La + 27 Al, 51 V, nat Cu were also studied by combining a dynamical model calculation that simulates the early stages of nuclear reactions with a statistical model calculation for the latter stages of the reactions. For the reaction 139 La + 27 Al, these calculations reproduced many of the experimental features, but other features were not reproduced. For the reaction 139 La + 51 V, the calculation failed to reproduce somewhat more of the experimental features. The calculation failed to reproduce any of the experimental features of the reaction 139 La + nat Cu, with the exception of the source velocity distributions

A variable reaction rate model for chlorine decay in drinking water due to the reaction with dissolved organic matter.

Science.gov (United States)

Hua, Pei; Vasyukova, Ekaterina; Uhl, Wolfgang

2015-05-15

A second order kinetic model for simulating chlorine decay in bulk water due to the reaction with dissolved organic matter (DOM) was developed. It takes into account the decreasing reactivity of dissolved organic matter using a variable reaction rate coefficient (VRRC) which decreases with an increasing conversion. The concentration of reducing species is surrogated by the maximum chlorine demand. Temperature dependency, respectively, is described by the Arrhenius-relationship. The accuracy and adequacy of the proposed model to describe chlorine decay in bulk water were evaluated and shown for very different waters and different conditions such as water mixing or rechlorination by applying statistical tests. It is thus very well suited for application in water quality modeling for distribution systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bondi-Hoyle-Lyttleton Accretion onto Binaries

Science.gov (United States)

Antoni, Andrea; MacLeod, Morgan; Ramírez-Ruiz, Enrico

2018-01-01

Binary stars are not rare. While only close binary stars will eventually interact with one another, even the widest binary systems interact with their gaseous surroundings. The rates of accretion and the gaseous drag forces arising in these interactions are the key to understanding how these systems evolve. This poster examines accretion flows around a binary system moving supersonically through a background gas. We perform three-dimensional hydrodynamic simulations of Bondi-Hoyle-Lyttleton accretion using the adaptive mesh refinement code FLASH. We simulate a range of values of semi-major axis of the orbit relative to the gravitational focusing impact parameter of the pair. On large scales, gas is gravitationally focused by the center-of-mass of the binary, leading to dynamical friction drag and to the accretion of mass and momentum. On smaller scales, the orbital motion imprints itself on the gas. Notably, the magnitude and direction of the forces acting on the binary inherit this orbital dependence. The long-term evolution of the binary is determined by the timescales for accretion, slow down of the center-of-mass, and decay of the orbit. We use our simulations to measure these timescales and to establish a hierarchy between them. In general, our simulations indicate that binaries moving through gaseous media will slow down before the orbit decays.

Electronic computer prediction of the type of the crystallization reaction of binary compounds on the base of electronic structure of components

International Nuclear Information System (INIS)

Kutolin, S.A.; Kotyukov, V.I.

1979-01-01

Presented are the criteria permitting to predict distectic and peritectic reactions of crystallization in narrow and wide regions of homogeneity of Asub(n)Bsub(m) binary compounds. Criteria are found as a result of identification of the crystallization reaction type for one hundred of known binary compounds. Predicting function arguments are Chebishev coefficients whose polynomials describe energy distribution of s-, p-, d-atoms of bands of corresponding compound components in condensed state and also Fermi energy atate in compound components and a content. Prediction relative error of distectic (peritectic) crystallization reaction is 6%, for wide homogeneity region - not more than 12 rel.% (for narrow - up to 1 at%). Presented are the prediction results for the most part of A 3 B and AB 3 binary compounds as well as the rare earth compounds of various composition

Chemical effects of the radioactive decay 7677Kr→7677Br reactions of recoil bromine in the gas phase

International Nuclear Information System (INIS)

Jong, D. de.

1982-01-01

This thesis describes the chemical reactions of 76 Br and 77 Br recoil species, formed by radioactive decay of 76 Kr and 77 Kr, with various gaseous compounds. Due to differences in decay energy and decay mode the resulting 76 Br and 77 Br isotopes obtain different kinetic energies and carry different charges; 76 Kr decays completely via electron capture and the resulting 76 Br is formed with a multiple positive charge and a kinetic energy of 7.2 eV at the most. 77 Kr decays for only 16% via electron capture, resulting in 77 Brsup(n+) ions with a maximal kinetic energy of 56.9 eV. 84% of the 77 Kr decays via #betta# + particle emission, which leads to 77 Br species, that are mainly negative or uncharged and that possess a maximal kinetic energy of 36.4 eV. The aim of this study was to explore whether these initial differences in charge and kinetic energy are reflected in the products, formed after chemical reactions of 76 Br and 77 Br. (Auth.)

Ion-molecular reactions initiated by β-decay of tritium in tritiated compounds

International Nuclear Information System (INIS)

Akulov, G.P.

1976-01-01

Ion-molecular reactions initiated by β-decay of tritium and tritiated hydrocarbons have been systematized. The review describes the theoretical and experimental foundation of the radiochemical method of this important type of chemical interactions investigation. The reactions of the molecular ions of HeT + with methane, ethane, propane, butane and also with cycloalkanes from C 3 to C 6 are discussed. The reactions under consideration have been united into two groups: reactions involving HeT + ions and those involving carbonic ions. From the experimental results available, the conclusions have been drawn about the reactivity of these intermediate formations, about the mechanism of their interaction with organic substances, and also about the perspectives of using the radiochemical method in studies of ion-molecular reactions. The experimental results published before May 1974 are examined. The bibliography includes 162 references

DCHAIN: A user-friendly computer program for radioactive decay and reaction chain calculations

International Nuclear Information System (INIS)

East, L.V.

1994-05-01

A computer program for calculating the time-dependent daughter populations in radioactive decay and nuclear reaction chains is described. Chain members can have non-zero initial populations and be produced from the preceding chain member as the result of radioactive decay, a nuclear reaction, or both. As presently implemented, chains can contain up to 15 members. Program input can be supplied interactively or read from ASCII data files. Time units for half-lives, etc. can be specified during data entry. Input values are verified and can be modified if necessary, before used in calculations. Output results can be saved in ASCII files in a format suitable for including in reports or other documents. The calculational method, described in some detail, utilizes a generalized form of the Bateman equations. The program is written in the C language in conformance with current ANSI standards and can be used on multiple hardware platforms

MODESTY, Statistical Reaction Cross-Sections and Particle Spectra in Decay Chain

International Nuclear Information System (INIS)

Mattes, W.

1977-01-01

1 - Nature of the physical problem solved: Code MODESTY calculates all energetically possible reaction cross sections and particle spectra within a nuclear decay chain. 2 - Method of solution: It is based on the statistical nuclear model following the method of Uhl (reference 1) where the optical model is used in the calculation of partial widths and the Blatt-Weisskopf single particle model for gamma rays

Binary and tertiary neutron induced reaction cross sections of chromium and iron

International Nuclear Information System (INIS)

Garg, S.B.

1989-01-01

Investigation has been carried out for the following binary and tertiary reaction cross-sections of Cr-52 and Fe-56: (n,p), (n,pn), (n,np), (n,α), (n, nα), (n, 2n) and (n, 3n), energy spectra of the emitted neutron, proton, α-particle and γ-rays, angle-energy correlated double differential cross-sections for the secondary emitted neutrons and total production cross-sections for neutron, hydrogen, helium and gamma-rays. 12 refs, 20 figs, 1 tab

Determination of reaction cross sections with the aid of α decay in the 12C, 14C + 209Bl reactions

International Nuclear Information System (INIS)

Hick, H.

1980-01-01

For the reactions 14 C + 209 Bi and 12 C + 209 Bi excitation functions at energies in the range between 57 MeV and 76 MeV are measured. Radiative capture and particle evaporation cross sections were determined by means of α-spectroscopy, and fission cross sections were determined by the measurement of the γ-radiation after the β-decay of the fission products. For the radiative capture for the reaction 14 C + 209 Bi upper limits for the cross section from 21 nbarn to 178 nbarn in the energy interval 61-74 MeV were determined. The fission cross sections were 80 +- 30 mbarn at 490 +- 200 mbarn at 76 MeV. For the reaction 12 C + 209 Bi three new α-lines were found. They were due to the slope at their excitation functions assigned to the decay of isomeric states of following nuclei: 219 Ac Esub(α) = 9419 +- 4 keV Tsub(1/2) = 830 +- 100/μsec, 218 Ac Esub(α) = 9271 +- 4 keV Tsub(1/2) = 810 +- 70/μsec, 217 Ac Eα = 9730 +- 5 keV Tsub(1/2) = 970 +- 190/μsec. For the reactions respectively 12 C + 209 Bi calculations using the statistical model code Grogi of J. Gilat are performed. The calculated branchings of the evaporation channels were compared with the experiment. (orig./HSI) [de

Three-body correlations in the decay of $^{10}$He and $^{13}$Li

CERN Document Server

Jonson, B; Cortina-Gil, D; Simon, H; Emling, H; Nyman, G; Nilsson, T; Johansson, H T; Borge, M J G; Paschalis, S; Muenzenberg, G; Zhukov, M V; Weick, H; Pramanik, U Datta; LeBleis, T; Meister, M; Reifarth, R; Chulkov, L V; Lantz, M; Riisager, K; Mahata, K; Suemmerer, K; Langer, C; Chatillon, A; Richter, A; Kulessa, R; Palit, R; Aksyutina, Yu; Geissel, H; Aumann, T; Shulgina, N B; Prokopowicz, W; Forssen, C; Ickert, G; Fynbo, H O U; Tengblad, O; Boretzky, K

2010-01-01

The very exotic nuclear resonance systems. He-10 and Li-13, are produced in proton-knockout reactions from relativistic beams of Li-11 and Be-14. The experimentally determined energy and angular correlations between their decay products, He-8 + n + n and Li-11 + n + n, are analyzed using an expansion of decay amplitudes in a restricted set of hyperspherical harmonics. By considering only a small number of terms it is possible to extract the expansion coefficients directly from the experimental three-body correlations. This provides a model-independent way of getting information about the decay process. on the structure of the decaying nucleus and on the quantum characteristics of the binary subsystems The results show that the He-8 + n + n relative-energy spectrum can be interpreted as consisting of two resonances, an I-pi = 0(+) ground state and an excited I-pi = 2(+) state. The Li-11 + n + n relative-energy spectrum is interpreted as an I-pi = 3/2(-) ground state overlapping with excited states having a str...

Measuring nuclear reaction cross sections to extract information on neutrinoless double beta decay

Science.gov (United States)

Cavallaro, M.; Cappuzzello, F.; Agodi, C.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Branchina, V.; Bussa, M. P.; Calabrese, S.; Calabretta, L.; Calanna, A.; Calvo, D.; Carbone, D.; Chávez Lomelí, E. R.; Coban, A.; Colonna, M.; D'Agostino, G.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; de Faria, P. N.; Ferraresi, C.; Ferreira, J. L.; Finocchiaro, P.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia, U.; Giraudo, G.; Greco, V.; Hacisalihoglu, A.; Kotila, J.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lavagno, A.; La Via, F.; Lay, J. A.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lo Presti, D.; Lubian, J.; Medina, N.; Mendes, D. R.; Muoio, A.; Oliveira, J. R. B.; Pakou, A.; Pandola, L.; Petrascu, H.; Pinna, F.; Reito, S.; Rifuggiato, D.; Rodrigues, M. R. D.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Sgouros, O.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Tudisco, S.; Vsevolodovna, R. I. M.; Wheadon, R. J.; Yildirin, A.; Zagatto, V. A. B.

2018-02-01

Neutrinoless double beta decay (0vββ) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research “beyond Standard Model” and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0vββ decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract information on the 0vββ Nuclear Matrix Elements. In DCE reactions and ββ decay indeed the initial and final nuclear states are the same and the transition operators have similar structure. Thus the measurement of the DCE absolute cross-sections can give crucial information on ββ matrix elements. In a wider view, the NUMEN international collaboration plans a major upgrade of the INFN-LNS facilities in the next years in order to increase the experimental production of nuclei of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest as candidates for 0vββ.

Recoil implantation reactions in binary mixtures of catcher complexes and in mixed ligand catchers

International Nuclear Information System (INIS)

Sekine, Tsutomu; Sano, Masaaki; Yoshihara, Kenji

1989-01-01

Recoil implantation reactions were studied in binary mixtures of catcher complexes of tris(β-diketonato)metal(III) and in single-component catcher complexes of Cr(acac) n (dbm) 3-n where n=1 and 2. For the mixtures of M(acac) 3 and M(dbm) 3 , the products of 51 Cr(acac) 3 and 51 Cr(dbm) 3 were obtained as major components while 51 Cr(acac) 2 (dbm) and 51 Cr(acac)(dbm) 2 were seen as minor components. For the single component catcher complexes, predominant chemical species were parent retention type compounds. In addition to retentions there were product distributions which indicated a strong preference for acac pickup. The results were interpreted by a model which involves displacement reaction as a main process and ligand pickup reactions as side processes. (orig.)

Study of the mechanism of Pb + Au reaction at 29 A.MeV; Etude du mecanisme de la reaction Pb + Au a 29 A.MeV

Energy Technology Data Exchange (ETDEWEB)

Aboufirassi, M

1994-07-01

The aim of this thesis is to demonstrate the binary character of Pb + Au reaction at 29 A.MeV and to study the decay modes of very excited nuclei produced. The experiment set up was performed at the GANIL in the scattering chamber NAUTILUS. It was composed by multi detectors of fragments (Z {>=}8) and multi detectors of light charged particles. (Z<8). The analysis of events which lead to detection of more then 80 % of both total charge and total parallel momentum proved that two body final state is still present at this incident energy. This mechanism is similar to the mechanism of heavy ion reaction at low bombarding energy. We have shown that complete damping occurred leading to excitation energy as high as 6 Me V/u. The decay modes of deep inelastic products are evaporation residue or binary fission or multifragmentation. Analysing the fission products, we have estimated the aligned spin of deep inelastic products (45 h). Finally, the study of light charged particles detected with fission fragments has demonstrated that these particles are emitted essentially before fission. The temperature value of hot nuclei emitted at foreword angle is deduced of light particle spectra. (author). 59 refs.

TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

International Nuclear Information System (INIS)

Fuller, Jim; Lai Dong

2012-01-01

Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10 5 -10 6 years.

Kinetics of free radical decay reactions in lactic acid homo and copolymers irradiated to sterilization dose

International Nuclear Information System (INIS)

Kantoglu, O.; Ozbey, T.; Gueven, O.

1995-01-01

The kinetics of free radical decay reactions of poly(L-Lactic acid), poly(DL-Lactic acid) and random copolymer of lactic and glycolic acid have been investigated for decays taking place in air and in vacuum. The change in ESR lines of γ-irradiated polymers have been followed over a long time period. The decay has been found to follow neither simple first-order nor second-order kinetics. Various kinetic approaches including composite first or second-order mechanisms and diffusion-controlled first or second-order equations were determined to be also unsatisfactory. The decay of radicals in bulk irradiated lactic acid homo and copolymers was found to be best described when the second-order non-classical equation with time dependent rate constant approach was used. (Author)

Clustering effects in fusion evaporation reactions with light even-even N=Z nuclei. The 24Mg and 28Si cases

Directory of Open Access Journals (Sweden)

Morelli L.

2016-01-01

Inclusive variables are in general well reproduced by the model. We found clear deviations from the statistical model if we select emission channels involving multiple α particles which are more probable than expected from a purely statistical behavior. Data from 12C+12C reaction have been analyzed in order to study the decay of the Hoyle state of 12C* with two different selections: peripheral binary collisions and 6α decay channel in central events. To continue the investigation on light systems, we have recently measured the 16O+12C reaction at three different beam energies, namely Ebeam = 90, 110 and 130 MeV. Preliminary results are presented.

Coevolution of Binaries and Circumbinary Gaseous Disks

Science.gov (United States)

Fleming, David; Quinn, Thomas R.

2018-04-01

The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

Statistical multifragmentation: Is the distinction between simultaneous and sequential decay inessential?

International Nuclear Information System (INIS)

Moretto, L.G.; Delis, D.N.; Wozniak, G.J.

1994-01-01

Recently, some experimental work has succeeded in isolating and characterizing what appear to be true multifragmentation sources formed in reverse kinematics reactions. These sources are formed in a process akin to incomplete fusion, whereby one partner of the collision picks up, and fuses with, a variable portion of the other partner. From the kinematics of the event, it is possible to determine how much mass has been picked up and what is the excitation energy associated with the fused object. Surprisingly, these sources, once characterized as described above, undergo multifragment decay in a way that is singularly independent of the formation process. The observed branching ratios for binary, ternary, quaternary, and quinary decays seem to depend almost exclusively upon the excitation energy E of the fused object, and remarkably little upon the target-projectile combination or even the bombarding energy. A powerful method is devised to verify the statistical competition between two-, three-, four-, and n-body decays. It is shown that under rather general conditions, the simultaneous n-body multifragmentation probability can be reduced to the n-1 step sequential probability

Measurement of the 6He Decay Produced by the 9Be(n, α) 6 He Reaction

Science.gov (United States)

Cook, Katelyn; Coats, Micah; Yuly, Mark; Padalino, Stephen; Sangster, Craig; Regan, Sean

2016-10-01

The OMEGA laser at LLE is routinely used to implode gas-filled capsules to study light ion fusion reaction rates of interest to stellar nucleosynthesis. As a first step toward a possible measurement of the 3H(t,γ)6He radiative capture reaction, a detector system capable of measuring the 801 ms half-life of 6He has been developed and is being tested using 6He nuclei produced via the 9Be(n,α)6He reaction. Deuterons from the SUNY Geneseo tandem Pelletron produce neutrons in a thick deuterated polyethylene target via the 2H(d,n)3He reaction. These neutrons are allowed to strike a beryllium target placed in front of a silicon ΔE-E detector telescope, which is used to identify the β particles from 6He decay. Following an approximately five second long activation period, the beryllium sample is immediately counted for about five seconds. The pulse heights for each detector and the timestamp are recorded using a specially configured femtoDAQ acquision system and used to measure the decay curve. Funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Calculation for fission decay from heavy ion reactions at intermediate energies

International Nuclear Information System (INIS)

Blaich, T.; Begemann-Blaich, M.; Fowler, M.M.; Wilhelmy, J.B.; Britt, H.C.; Fields, D.J.; Hansen, L.F.; Namboodiri, M.N.; Sangster, T.C.; Fraenkel, Z.

1992-01-01

A detailed deexcitation calculation is presented for target residues resulting from intermediate-energy heavy ion reactions. The model involves an intranuclear cascade, subsequent fast nucleon emission, and final decay by statistical evaporation including fission. Results are compared to data from bombardments with Fe and Nb projectiles on targets of Ta, Au, and Th at 100 MeV/nucleon. The majority of observable features are reproduced with this simple approach, making obvious the need for involving new physical phenomena associated with multifragmentation or other collective dissipation mechanisms

Study of the mechanism of Pb + Au reaction at 29 A.MeV

International Nuclear Information System (INIS)

Aboufirassi, M.

1994-07-01

The aim of this thesis is to demonstrate the binary character of Pb + Au reaction at 29 A.MeV and to study the decay modes of very excited nuclei produced. The experiment set up was performed at the GANIL in the scattering chamber NAUTILUS. It was composed by multi detectors of fragments (Z ≥8) and multi detectors of light charged particles. (Z<8). The analysis of events which lead to detection of more then 80 % of both total charge and total parallel momentum proved that two body final state is still present at this incident energy. This mechanism is similar to the mechanism of heavy ion reaction at low bombarding energy. We have shown that complete damping occurred leading to excitation energy as high as 6 Me V/u. The decay modes of deep inelastic products are evaporation residue or binary fission or multifragmentation. Analysing the fission products, we have estimated the aligned spin of deep inelastic products (45 h). Finally, the study of light charged particles detected with fission fragments has demonstrated that these particles are emitted essentially before fission. The temperature value of hot nuclei emitted at foreword angle is deduced of light particle spectra. (author)

Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

Science.gov (United States)

Ejiri, Hiroyasu

2014-09-01

Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.

{gamma} decay of spin-isospin states in {sup 13}N via ({sup 3}He, t{gamma}) reaction

Energy Technology Data Exchange (ETDEWEB)

Ihara, F; Akimune, H; Daito, I; Fujimura, H; Fujiwara, M; Inomata, T; Ishibashi, K; Yoshida, H [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics; Fujita, Y

1998-03-01

Spin-isospin states in {sup 13}N have been studied by means of the {sup 13}C ({sup 3}He,t) reaction at and near zero degree, at E({sup 3}He)=450 MeV. Decayed {gamma}-rays from each state were measured at backward angle in coincidence with the ejectile tritons. The branching ratio of {gamma} decay for some of spin-isospin states were determined and were compared to those from previous data. (author)

Exact statistical results for binary mixing and reaction in variable density turbulence

Science.gov (United States)

Ristorcelli, J. R.

2017-02-01

We report a number of rigorous statistical results on binary active scalar mixing in variable density turbulence. The study is motivated by mixing between pure fluids with very different densities and whose density intensity is of order unity. Our primary focus is the derivation of exact mathematical results for mixing in variable density turbulence and we do point out the potential fields of application of the results. A binary one step reaction is invoked to derive a metric to asses the state of mixing. The mean reaction rate in variable density turbulent mixing can be expressed, in closed form, using the first order Favre mean variables and the Reynolds averaged density variance, ⟨ρ2⟩ . We show that the normalized density variance, ⟨ρ2⟩ , reflects the reduction of the reaction due to mixing and is a mix metric. The result is mathematically rigorous. The result is the variable density analog, the normalized mass fraction variance ⟨c2⟩ used in constant density turbulent mixing. As a consequence, we demonstrate that use of the analogous normalized Favre variance of the mass fraction, c″ ⁣2˜ , as a mix metric is not theoretically justified in variable density turbulence. We additionally derive expressions relating various second order moments of the mass fraction, specific volume, and density fields. The central role of the density specific volume covariance ⟨ρ v ⟩ is highlighted; it is a key quantity with considerable dynamical significance linking various second order statistics. For laboratory experiments, we have developed exact relations between the Reynolds scalar variance ⟨c2⟩ its Favre analog c″ ⁣2˜ , and various second moments including ⟨ρ v ⟩ . For moment closure models that evolve ⟨ρ v ⟩ and not ⟨ρ2⟩ , we provide a novel expression for ⟨ρ2⟩ in terms of a rational function of ⟨ρ v ⟩ that avoids recourse to Taylor series methods (which do not converge for large density differences). We have derived

Comparative decay analysis of 179Re* and 189Au* formed in the reactions 20Ne+159Tb, 169Tm with Elab=8 MeV/A

International Nuclear Information System (INIS)

Manpreet Kaur; Singh, BirBikram

2016-01-01

The heavy ion induced reactions lead to the formation of composite systems, which subsequently decay because of high excitation energy and angular momentum. The study of decaying composite system facilitates to explore the number of nuclear characteristics and the reaction dynamics. The medium mass composite systems 164 Yb*, 176,182,188,196 Pt* and 200,202 Pb* have been studied successfully within the framework of dynamical cluster decay model (DCM). These studies show the emission of light particles, LP (or evaporation residues, ER), intermediate mass fragments, IMF, heavy mass fragments, HMF and symmetric fragments, SF along with signatures of quasi-fission, qf, process in their decay path. The decay of medium mass composite system 179 Re* has also been studied within DCM. In the present work, we investigate the comparative decay of two medium mass composite systems 179 Re* and 189 Au formed in the reactions with same projectile ( 20 Ne) having same E lab (or same E/A) on two different targets 159 Tb and 169 Tm, for which the experimental data is available

Ion-molecule reactions in the binary mixture of ethylene oxide and trioxane, 2

International Nuclear Information System (INIS)

Kumakura, Minoru; Arakawa, Kazuo; Sugiura, Toshio.

1978-01-01

The ion-molecule reactions in the binary mixture of ethylene oxide and trioxane have been studied with use of a modified time-of-flight mass spectrometer. As cross-reaction product ions, C 3 H 5 O 2 + , C 3 H 6 O 2 +sup(, and C**3**H**7**O**2**)+sup( were observed under the conditions of long delay times and elevated pressure. It was found that these ions are formed by the dissociation of unstable intermediate-complex resulting from the reaction of ethylene oxide molecular ion with trioxane. It was proposed that the complex is of cyclic structure in which positive charge is delocalized. From the consideration of isotopic distribution of the product ions in ethylene-d**4** oxide-trioxane mixtures, the skeletal structures of the product ions were investigated. The rate constants of the formation reactions of C**3**H**5**O**2**)+sup(, C**3**H**6**O**2**)+sup(, and C**3**H**7**O**2**)+sup( in ethylene oxide-trioxane mixtures were found to be 2.20 x 10)-10sup(, 2.61 x 10)-10sup(, and 1.74 x 10)-10sup( cm)3sup( molecule)-1sup(s)-1 , respectively. (auth.)

Decay analysis of compound nuclei formed in reactions with exotic neutron-rich 9Li projectile and the synthesis of 217At* within the dynamical cluster-decay model

Science.gov (United States)

Kaur, Arshdeep; Kaushal, Pooja; Hemdeep; Gupta, Raj K.

2018-01-01

The decay of various compound nuclei formed via exotic neutron-rich 9Li projectile is studied within the dynamical cluster-decay model (DCM). Following the earlier work of one of us (RKG) and collaborators (M. Kaur et al. (2015) [1]), for an empirically fixed neck-length parameter ΔRemp, the only parameter in the DCM, at a given incident laboratory energy ELab, we are able to fit almost exactly the (total) fusion cross section σfus =∑x=16σxn for 9Li projectile on 208Pb and other targets, with σfus depending strongly on the target mass of the most abundant isotope and its (magic) shell structure. This result shows the predictable nature of the DCM. The neck-length parameter ΔRemp is fixed empirically for the decay of 217At* formed in 9Li + 208Pb reaction at a fixed laboratory energy ELab, and then the total fusion cross section σfus calculated for all other reactions using 9Li as a projectile on different targets. Apparently, this procedure could be used to predict σfus for 9Li-induced reactions where experimental data are not available. Furthermore, optimum choice of "cold" target-projectile combinations, forming "hot" compact configurations, are predicted for the synthesis of compound nucleus 217At* with 8Li + 209Pb as one of the target-projectile combination, or another (t , p) combination 48Ca + 169Tb, with a doubly magic 48Ca, as the best possibility.

Limitation on the constant of heavy lepton radiative decay according to data of the e+e- → γ + γ reactions

International Nuclear Information System (INIS)

Gakh, G.I.

1976-01-01

The effect of a heavy lepton in an intermediate state on the differential and total cross sections of the e + e - → γγ reaction has been investigated in order to obtain information on heavy lepton radiative decay L → eγ. On the basis of experimental data on the reaction the limitations on the constant lambda of the decay L → eγ are obtained as functions of the heavy lepton mass. It turns out that the upper limit for lambda rapidly increases with the heavy lepton mass and at m > 1 GeV lambda 2 > 0.1

On the solid–liquid phase diagrams of binary mixtures of even saturated fatty alcohols: Systems exhibiting peritectic reaction

Energy Technology Data Exchange (ETDEWEB)

Carareto, Natália D.D. [EXTRAE, Department of Food Engineering, Food Engineering Faculty, University of Campinas, UNICAMP, CEP 13083-862 Campinas, SP (Brazil); Santos, Adenílson O. dos [Social Sciences, Health and Technology Center, University of Maranhão, UFMA, CEP 65900-410 Imperatriz, MA (Brazil); Rolemberg, Marlus P. [Institute of Science and Technology, University of Alfenas, UNIFAL, Rodovia José AurélioVilela, CEP 37715400 Poços de Caldas, MG (Brazil); Cardoso, Lisandro P. [Institute of Physics GlebWataghin, University of Campinas, UNICAMP, C.P. 6165, CEP 13083-970 Campinas, SP (Brazil); Costa, Mariana C. [School of Applied Science, University of Campinas, UNICAMP, CEP 13484-350 Limeira, SP (Brazil); Meirelles, Antonio J.A., E-mail: tomze@fea.unicamp.br [EXTRAE, Department of Food Engineering, Food Engineering Faculty, University of Campinas, UNICAMP, CEP 13083-862 Campinas, SP (Brazil)

2014-08-10

Highlights: • SLE of binary mixtures of saturated fatty alcohols was studied. • Experimental data were obtained using DSC and stepscan DSC. • Microscopy and X-ray diffraction used as complementary techniques. • Systems presented eutectic, peritectic and metatectic points. - Abstract: The solid–liquid phase diagrams of the following binary mixtures of even saturated fatty alcohols are reported in the literature for the first time: 1-octanol (C8OH) + 1-decanol (C10OH), 1-decanol + 1-dodecanol (C12OH), 1-dodecanol + 1-hexadecanol (C16OH) and 1-tetradecanol (C14OH) + 1-octadecanol (C18OH). The phase diagrams were obtained by differential scanning calorimetry (DSC) using a linear heating rate of 1 K min{sup −1} and further investigated by using a stepscan DSC method. X-ray diffraction (XRD) and polarized light microscopy were also used to complement the characterization of the phase diagrams which have shown a complex global behavior, presenting not only peritectic and eutectic reactions, but also the metatectic reaction and partial immiscibility on solid state.

On the solid–liquid phase diagrams of binary mixtures of even saturated fatty alcohols: Systems exhibiting peritectic reaction

International Nuclear Information System (INIS)

Carareto, Natália D.D.; Santos, Adenílson O. dos; Rolemberg, Marlus P.; Cardoso, Lisandro P.; Costa, Mariana C.; Meirelles, Antonio J.A.

2014-01-01

Highlights: • SLE of binary mixtures of saturated fatty alcohols was studied. • Experimental data were obtained using DSC and stepscan DSC. • Microscopy and X-ray diffraction used as complementary techniques. • Systems presented eutectic, peritectic and metatectic points. - Abstract: The solid–liquid phase diagrams of the following binary mixtures of even saturated fatty alcohols are reported in the literature for the first time: 1-octanol (C8OH) + 1-decanol (C10OH), 1-decanol + 1-dodecanol (C12OH), 1-dodecanol + 1-hexadecanol (C16OH) and 1-tetradecanol (C14OH) + 1-octadecanol (C18OH). The phase diagrams were obtained by differential scanning calorimetry (DSC) using a linear heating rate of 1 K min −1 and further investigated by using a stepscan DSC method. X-ray diffraction (XRD) and polarized light microscopy were also used to complement the characterization of the phase diagrams which have shown a complex global behavior, presenting not only peritectic and eutectic reactions, but also the metatectic reaction and partial immiscibility on solid state

Dropping and semimicrotest glass reactions on beryllium, lenthanum, vanadyl and uranyl cations with synthetic organic dyes and their mutual determination in binary mixtures

International Nuclear Information System (INIS)

Shemyakin, F.M.; Novikova, A.A.; Reshetnyak, V.Yu.; Teplyakov, G.K.; Nekrasov, E.L.

1978-01-01

Coloured reactions for beryllium, lanthanum, vanadyl and uranyl cations with a number of organic dyes, have been studied. These reactions are used in dropping analysis on papers, impregnated with relevant dyes, and for semimicro-test glass reactions on the above cations. Sensitivity and maximum permissible dilution have been determined for each of the reactions. Mutual determinations of relevant couples of the above cations have been performed. It is shown, that such binary mixtures enable to freely open relevant cations

78Kr(α,γ) reaction of astrophysical interest in inverse kinematics and the electronic screening effect on the beta decay

International Nuclear Information System (INIS)

Ujic, P.

2011-12-01

The thesis is constituted of two different topics related to astrophysics. The titles of these topics are: 'Alpha capture reaction in inverse kinematics, measurement of 78 Kr(α,γ) 82 Sr reaction' and 'Measurement of the radioactive decay of 19 O and 19 Ne implanted in niobium'. The goal of the first part of the thesis was to establish an experimental technique for measuring radiative alpha capture reaction at low energies in inverse kinematics. The measurement of these reactions is very important in astrophysics since it will help to improve the reliability of alpha particle optical model potentials which are used for prediction of cross sections of nuclear reaction used in different astrophysical models of supernovae explosions. In this part we insisted on a technical feasibility of this type of experiment. In the second part of the thesis, we examined the influence of the environment on the beta decay probability, in particular the influence of the electronic screening of Coulomb barrier of nuclei induced by Cooper pairs in superconductors. The indication of an extremely weak effect was noticed. (author)

Search for the rare decay π0→e+e- and measurement of the π-p→e+e-n reaction at 304 MeV/c

International Nuclear Information System (INIS)

Zephat, A.G.

1983-01-01

The experiment described was performed to measure the branching ratio for the π 0 →e + e - decay. With an accurate value for the branching ratio more can be learned about the interactions which play a role in this decay. With this experiment, information can also be obtained about the cross section for the reaction π - d→e + e - n. An upper limit of 8x10 -7 was obtained for the π 0 decay branching ratio. A value for the cross section of the π - p reaction of 68+-15 nbarn is derived. (Auth.)

TIDAL STELLAR DISRUPTIONS BY MASSIVE BLACK HOLE PAIRS. II. DECAYING BINARIES

International Nuclear Information System (INIS)

Chen Xian; Liu, F. K.; Sesana, Alberto; Madau, Piero

2011-01-01

Tidal stellar disruptions have traditionally been discussed as a probe of the single, massive black holes (MBHs) that are dormant in the nuclei of galaxies. We have previously used numerical scattering experiments to show that three-body interactions between bound stars in a stellar cusp and a non-evolving 'hard' MBH binary will also produce a burst of tidal disruptions, caused by a combination of the secular 'Kozai effect' and by close resonant encounters with the secondary hole. Here, we derive basic analytical scalings of the stellar disruption rates with the system parameters, assess the relative importance of the Kozai and resonant encounter mechanisms as a function of time, discuss the impact of general relativistic (GR) and extended stellar cusp effects, and develop a hybrid model to self-consistently follow the shrinking of an MBH binary in a stellar background, including slingshot ejections and tidal disruptions. In the case of a fiducial binary with primary hole mass M 1 = 10 7 M sun and mass ratio q = M 2 /M 1 = 1/81, embedded in an isothermal cusp, we derive a stellar disruption rate N-dot * ∼ 0.2 yr -1 lasting ∼3 x 10 5 yr. This rate is three orders of magnitude larger than the corresponding value for a single MBH fed by two-body relaxation, confirming our previous findings. For q 10% of the tidal-disruption events may originate in MBH binaries.

High resolution 148Nd(3He, ny) two proton stripping reaction and the structure of the O2+ state in 150Sm

International Nuclear Information System (INIS)

Sharpey-Schafer, J.F.; Dinoko, T.S.; Herbert, M.S.; Orce, J.N.; Papka, P.; Kheswa, B.V.; Ndayishimye, J.; Bvumbi, S.P.; Jones, P.M.; Bucher, T.D.; Lawrie, E.A.; Lawrie, J.J.; Negi, D.; Shirinda, O.; Wiedeking, M.; Vymers, P.; Easton, J.L.; Noncolela, S.P.; Sithole, P.; Khumalo, N.; Majola, S.N.T.; Stankiewicz, M.A.

2014-01-01

The challenge of achieving high resolution in binary reactions involving an outgoing high energy neutron is solved by detecting the γ-ray decay of populated excited states in an array of escape suppressed HPGe detectors in coincidence with fast neutrons detected in a wall of scintillator detectors 2 m down beam of the target. The selectivity of the arrangement is of the order of 1 in 1000. The time-of-flight difference is sufficient to separate fast neutrons from direct reactions from a large background of statistical neutrons from fusion-evaporation reactions. Our interest is in the wavefunction of the 0 2 + state at 740 keV in the N=88 nucleus 150 Sm which, with the 0 2 + state in 100 Ru, are the only two excited states observed in 2β2ν double β-decay. (authors)

$\\beta$- decay of $^{58}$Zn. A critical test for the charge-exchange reaction as a probe for the $\\beta$- decay strength distribution

CERN Multimedia

2002-01-01

% IS353 \\\\ \\\\ Due to its importance in fundamental physics and astrophysics, a great effort both theoretically and experimentally is devoted to study Gamow Teller (GT)-strength. The GT-strength and its distribution play a key role in late stellar evolution. During the pre-supernova core-collapse of massive stars, the electron capture and nuclear $\\beta$ -decay determine the electron-to-baryon ratio, which influences the infall dynamics and the mass of the final core. The cross-section of the charge-exchange reaction at forward angles with energies above 100~MeV is expected to be proportional to the squares of Fermi and GT matrix elements. This proportionality should provide a Q-value free method to probe the weak interaction strength and renormalization effects in nuclei. Thus charge-exchange reactions are often used to determine the experimental GT-strength. However, the connection between the GT-strength and the cross-section of the charge-exchange reaction is partially model-dependent and the question aris...

Reducing orbital eccentricity in binary black hole simulations

International Nuclear Information System (INIS)

Pfeiffer, Harald P; Brown, Duncan A; Kidder, Lawrence E; Lindblom, Lee; Lovelace, Geoffrey; Scheel, Mark A

2007-01-01

Binary black hole simulations starting from quasi-circular (i.e., zero radial velocity) initial data have orbits with small but nonzero orbital eccentricities. In this paper, the quasi-equilibrium initial-data method is extended to allow nonzero radial velocities to be specified in binary black hole initial data. New low-eccentricity initial data are obtained by adjusting the orbital frequency and radial velocities to minimize the orbital eccentricity, and the resulting (∼5 orbit) evolutions are compared with those of quasi-circular initial data. Evolutions of the quasi-circular data clearly show eccentric orbits, with eccentricity that decays over time. The precise decay rate depends on the definition of eccentricity; if defined in terms of variations in the orbital frequency, the decay rate agrees well with the prediction of Peters (1964 Phys. Rev. 136 1224-32). The gravitational waveforms, which contain ∼8 cycles in the dominant l = m = 2 mode, are largely unaffected by the eccentricity of the quasi-circular initial data. The overlap between the dominant mode in the quasi-circular evolution and the same mode in the low-eccentricity evolution is about 0.99

Fission-like decay of 20Ne: eccentric behavior in the B+B fusion processes

International Nuclear Information System (INIS)

Toledo, A.S. de; Coimbra, M.M.; Added, N.; Anjos, R.M.; Carlin Filho, N.; Fante Junior, L.; Figueira, M.C.S.; Guimaraes, V.; Szanto, E.M.

1988-08-01

Cross sections for the fusion of 10,11 B+ 10,11 B have been measured in the energy range from 1.5 MeV/A to 5 MeV/A. The 10 B+ 10 B system unexpectedly presents a hindered fusion cross section when compared to the 10 B+ 11 B and 11 B+ 11 B reactions and to standard model predictions. The missing fusion cross section was diverted the 10 B exit channel with a total kinetic energy characteristic of strongly damped collisions. Q-values and kinematical analysis together with angular distributions suggest a binary symmetric decay of the composite 20 Ne system. (author) [pt

Strong binary pulsar constraints on Lorentz violation in gravity.

Science.gov (United States)

Yagi, Kent; Blas, Diego; Yunes, Nicolás; Barausse, Enrico

2014-04-25

Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of general relativity. One of these is Lorentz symmetry, which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

Strong Binary Pulsar Constraints on Lorentz Violation in Gravity

CERN Document Server

Yagi, Kent; Yunes, Nicolas; Barausse, Enrico

2014-01-01

Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of General Relativity. One of these is Lorentz symmetry which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.

General simulation algorithm for autocorrelated binary processes.

Science.gov (United States)

Serinaldi, Francesco; Lombardo, Federico

2017-02-01

The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

General simulation algorithm for autocorrelated binary processes

Science.gov (United States)

Serinaldi, Francesco; Lombardo, Federico

2017-02-01

The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

The 76Ge(n,p)76Ga reaction and its relevance to searches for the neutrino-less double-beta decay of 76Ge

Science.gov (United States)

Tornow, W.; Bhike, Megha; Fallin, B.; Krishichayan, Fnu

2015-10-01

The 76Ge(n,p)76Ga reaction and the subsequent β decay of 76Ga to 76Ge has been used to excite the 3951.9 keV state of 76Ge, which decays by emission of a 2040.7 keV γ ray. Using HPGe detectors, the associated pulse-height signal may be undistinguishable from the potential signal produced in neutrino-less double-beta decay of 76Ge with its Q-value of 2039.0 keV. In the neutron energy range between 10 and 20 MeV the production cross section of the 2040.7 keV γ ray is approximately 0.1 mb. In the same experiment γ rays of energy 2037.9 keV resulting from the 76Ge(n, γ)77Ge reaction were clearly observed. Adding the 76Ge(n,n' γ)76Ge reaction, which also produces the 2040.7 keV γ ray with a cross section value of the order of 0.1 mb clearly shows that great care has to be taken to eliminate neutron-induced backgrounds in searches for neutrino-less double-beta decay of 76Ge. This work was supported by the U.S. DOE under Grant NO. DE-FG02-97ER41033.

Intermediate nuclear structure for 2ν2β decay of 48Ca studied by (p, n) and (n, p) reactions at 300 MeV

International Nuclear Information System (INIS)

Sakai, H.; Yako, K.

2009-01-01

The two neutrino double beta (2ν2β) decay proceeds through a sequence of Gamow-Teller (GT) transitions, namely from the parent nucleus to the intermediate nucleus and then from the intermediate nucleus to the final daughter nucleus. The nuclear matrix element M 2ν for the 2ν2β - decay thus consists of the 2β - decay matrix elements for the parent nucleus decay and the 2β - decay matrix elements for the intermediate nucleus decay. These 2β - decay matrix elements can be studied experimentally through the (p, n) reaction for the parent nucleus decay and the (n, p) reaction for the intermediate nucleus decay. The 2ν2β-decay nucleus, 4 8C a is studied. The charge exchange (p, n) and (n, p) measurements at 300 MeV were performed using the neutron time-of-flight facility and the (n,p) facility, respectively, at RCNP. The (p, n) measurement on 4 8C a and the (n,p) measurement on 4 8T i provided us, for the first time, reliable B(GT - ) and B(GT + ) strength distributions up to high excitation energy of 30 MeV of the intermediate nucleus 4 8S c. The multipole decomposition analysis was applied to the angular distributions of the cross section spectra to extract the ΔL = 0 components, which are used to deduce B(GT ± ). Figure shows the double differential cross Nb sections for 4 8C a(p, n)4 8S c (left panel) and 4 8T i(n,p)4 8S c (right panel) reactions. The histograms show the results of the multi-pole decomposition analyses. It is very surprising to find sizable amount of ΔL = 0 yield, i.e. B(GT + ) strength in the highly excited energy region (> 10 MeV). The obtained B(GT ± ) distribution in 4 8S c as well as corresponding nuclear matrix elements M 2ν are compared with theoretical shell model calculation. In this talk, new results will be presented and their implication to the nuclear matrix elements for the 2ν2β-decay will be discussed (author)

Study of the production of heavy Λ hypernuclei in the (p,, K+) reaction below the N-N threshold and of their decay

International Nuclear Information System (INIS)

Schult, O.W.B.; Borgs, W.; Gotta, D.; Hamacher, A.; Koch, H.R.; Ohm, H.; Riepe, R.; Seyfarth, H.; Sistemich, K.; Drueke, V.; Filges, D.; Jarczyk, L.; Kistryn, S.; Smyrski, J.; Strzalkowski, A.; Styczen, B.; Brentano, P. von

1991-01-01

An experiment is briefly described which we are preparing for the study of heavy Λ hypernuclei, their formation in the (p, K + ) reaction, their Λ decay half life and other Λ decay features. The planned recoil shadow measurement of fission fragments is expected to yield the required background discrimination. The experiment uses the unique features of COSY-Juelich

The Decay of Bound Isobaric Analogue States in {sup 28}Si and {sup 32}S Using (d, n{gamma}) Reactions

Energy Technology Data Exchange (ETDEWEB)

Nilsson, L; Nilsson, A; Bergqvist, I

1970-03-15

A method has been developed for recording coincidences between neutrons and gamma - rays produced in (d, n{gamma}) reactions. Neutron energies were measured by time-of-flight techniques and a large Nal(Tl) crystal was used to determine gamma - ray energies and intensities. The neutron detector was placed in the forward direction to emphasize the excitation of l{sub P} = 0 levels in the residual nuclei. The method was applied to the {sup 27}Al (d, n{gamma}) {sup 28}Si and {sup 31}P (d, n{gamma}) {sup 32}S reactions at the deuteron energy 4.0 MeV. The gamma - ray decay of a number of levels below 12 MeV in {sup 28}Si and below 9 MeV in {sup 32}S was studied. The isobaric analogue levels are prominently populated by the (d, n) reaction. The method is in particular suitable for studies of the decay of these levels.

Decay of 143La

International Nuclear Information System (INIS)

Blachot, J.; Dousson, S.; Monnand, E.; Schussler, F.

1976-01-01

The decay of 143 La has been investigated. Sources have been obtained from 2 isotope separators (ISERE, OSIRIS). 12 gamma rays, with the most intense at 620keV representing only 1.4% of decay, have been attributed to the 143 La decay. A level scheme has been found and compared with the one deduced from (d,p) and (n,γ) reactions on 142 Ce [fr

Formation and decay of hot nuclei

International Nuclear Information System (INIS)

Planeta, R.

1999-01-01

Multifragmentation of excited nuclei of the 40 Ca + 40 Ca reaction at 35 MeV/nucleon has been studied using the multidetector system AMPHORA.Using special gating and reconstruction procedures we have observed projectile - like fragments, PLF, with different degrees of excitation, and also highly excited composite systems, CS, from incomplete fusion. This reconstruction procedure was verified by the Monte Carlo computer code of Sosin which describes the collision of heavy ions as a random walk transfer of nucleons. Agreement between the experimental data and the predictions of the code have strongly supported the thermalized character of the created hot sources. To investigate their decay characteristics we have used the conventional reduced velocity correlation method and also two signatures based on special features of particle emission from the 'freeze out volume'. They are: (i) - the distribution of the squared momentum of the heaviest emitted fragment; (ii) - the focusing of fragments by the Coulomb field of the decaying system. For the PLF, both methods, the reduced velocity correlation, and the distribution of the squared momentum of the heaviest emitted fragment, support the binary sequential decay, BSD, scenario below 3 MeV/nucleon excitation energy and prompt multifragmentation, PM, for higher excitations. For CS which has about twice the PLF electric charge the Coulomb focusing effect could be also observed. In that case all three signatures indicate prompt multifragmentation of the system contained inside the 'freeze-out' volume. Consistency of all these observations show that both the distribution of the squared momentum of the heaviest emitted fragment and the Coulomb focusing effect can be used as signatures of spinodal decomposition of 'hot' nuclear systems. (author)

48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr.

Science.gov (United States)

Khuyagbaatar, J; Yakushev, A; Düllmann, Ch E; Ackermann, D; Andersson, L-L; Asai, M; Block, M; Boll, R A; Brand, H; Cox, D M; Dasgupta, M; Derkx, X; Di Nitto, A; Eberhardt, K; Even, J; Evers, M; Fahlander, C; Forsberg, U; Gates, J M; Gharibyan, N; Golubev, P; Gregorich, K E; Hamilton, J H; Hartmann, W; Herzberg, R-D; Heßberger, F P; Hinde, D J; Hoffmann, J; Hollinger, R; Hübner, A; Jäger, E; Kindler, B; Kratz, J V; Krier, J; Kurz, N; Laatiaoui, M; Lahiri, S; Lang, R; Lommel, B; Maiti, M; Miernik, K; Minami, S; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Pang, G K; Papadakis, P; Renisch, D; Roberto, J; Rudolph, D; Runke, J; Rykaczewski, K P; Sarmiento, L G; Schädel, M; Schausten, B; Semchenkov, A; Shaughnessy, D A; Steinegger, P; Steiner, J; Tereshatov, E E; Thörle-Pospiech, P; Tinschert, K; Torres De Heidenreich, T; Trautmann, N; Türler, A; Uusitalo, J; Ward, D E; Wegrzecki, M; Wiehl, N; Van Cleve, S M; Yakusheva, V

2014-05-02

The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."

Light meson decays from photon-induced reactions with CLAS

Energy Technology Data Exchange (ETDEWEB)

Kunkel, Michael C. [Forschungszentrum Juelich (Germany); Collaboration: CLAS-Collaboration

2015-07-01

Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η' via conversion decays are performed using a line shape analysis on the invariant mass of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference are performed using a Dalitz plot analysis of the meson decay. In addition, the data allows for a search for dark matter, such as the heavy photon via conversion decays of light mesons and physics beyond the Standard Model is searched for via invisible decays of η mesons. An overview of the first results and future prospects is given.

β-delayed γ decay of 20Mg and the 19Ne(p , γ) 20 Na breakout reaction in Type I X-ray bursts

Science.gov (United States)

Glassman, B. E.; Pérez-Loureiro, D.; Wrede, C.; Allen, J.; Bardayan, D. W.; Bennett, M. B.; Brown, B. A.; Chipps, K. A.; Febbraro, M.; Friedman, M.; Fry, C.; Hall, M. R.; Hall, O.; Liddick, S. N.; O'Malley, P.; Ong, W. J.; Pain, S. D.; Prokop, C.; Schwartz, S. B.; Shidling, P.; Sims, H.; Thompson, P.; Zhang, H.

2018-03-01

Certain astrophysical environments such as thermonuclear outbursts on accreting neutron stars (Type-I X-ray bursts) are hot enough to allow for breakout from the Hot CNO hydrogen burning cycles to the rapid proton capture (rp) process. An important breakout reaction sequence is 15O(α,γ)19Ne(p,γ)20Na and the 19Ne(p,γ)20Na reaction rate is expected to be dominated by a single resonance at 457 keV above the proton threshold in 20Na. The resonance strength and, hence, reaction rate depends strongly on whether this 20Na state at an excitation energy of 2647 keV has spin and parity of 1+ or 3+. Previous 20Mg (Jπ =0+) β+ decay experiments have relied almost entirely on searches for β-delayed proton emission from this resonance in 20Na to limit the log ft value and, hence, Jπ. However there is a non-negligible γ-ray branch expected that must also be limited experimentally to determine the log ft value and constrain Jπ. We have measured the β-delayed γ decay of 20Mg to complement previous β-delayed proton decay work and provide the first complete limit based on all energetically allowed decay channels through the 2647 keV state. Our limit confirms that a 1+ assignment for this state is highly unlikely.

Giant resonance spectroscopy of 40Ca with the (e,e'x) reaction (III): Direct versus statistical decay

International Nuclear Information System (INIS)

Carter, J.; Diesener, H.; Helm, U.; Herbert, G.; Neumann-Cosel, P. von; Richter, A.; Schrieder, G.; Strauch, S.

2001-01-01

The present article is the third out of three on a study of the 40 Ca(e,e'x) reaction discussing the role of direct and statistical contributions to the decay of the observed giant resonance strengths. The proton and α decay modes leading to low-lying final states in 36 Ar and 39 K were investigated. The branching ratios for the p 0 , p 123 , α 0 and α 1 channels are compared to statistical model calculations. In the excitation region of dominant isoscalar E2 strength (E x =12-18 MeV) good agreement is observed. Model predictions of direct E2 decay for the (α 0 +α 1 )/(p 0 +p 1 ) ratio describe the data poorly. In the isovector E1 excitation region large excess strength is found in the population of low-lying states in 39 K. A fluctuation analysis shows the direct contributions to the p 0 , p 1 channels to be ≥85%. The presence of preequilibrium components is indicated by the significant nonstatistical decay to the p 3 level which has a dominant 'phonon·hole' structure. Cross correlations reveal no significant branching between the different channels. The correlations between different electron scattering angles in the p 0 , p 1 and p 3 decay result in an interaction radius compatible with the whole nucleus acting as an emitting source

Isomerization and self-condensation reactions subsequent the. beta. -decay of tritiated naphthalene in the presence of liquid and gaseous benzene

Energy Technology Data Exchange (ETDEWEB)

Angelini, G.; Keheyan, Y.; Lilla, E.; Perez, G. (Consiglio Nazionale delle Ricerche, Rome (Italy). Ist. di Chimica Nucleare)

1990-01-01

Tritiated napththylium ions, generated by spontaneous {beta}-decay of (1,4-{sup 3}H) naphthalene, have been allowed to react with benzene molecules in gaseous and liquid phase. The isomeric phenylnaphthalenes and fluoranthene have been found among the reaction products. The differences between the reactivity pattern of naphthylium ion in the two phases can be explained by the different efficiency of collisional stabilization of the excited reaction intermediates. (orig.).

Nuclear structure effects in fusion-fission of compound systems 20,21,22Ne formed in 10,11B+10,11B reactions

International Nuclear Information System (INIS)

Singh, BirBikram; Kaur, Manpreet; Kaur, Varinderjit; Gupta, Raj K.

2014-01-01

The dynamical cluster-decay model (DCM) of Gupta and collaborators has been successfully applied to the decay of number of hot and rotating compound nuclei in different mass regions, formed in low-energy heavy ion reactions. Recently, its application to the binary symmetric decay (BSD) of very light mass compound systems 20,21,22 Ne formed in 10,11 B+ 10,11 B reactions at E lab =48 MeV is extended, as the experimental data for σ BSD Expt . is available, namely, for 20 Ne (∼ 270 mb), 21 Ne ( 22 Ne ( BSD DCM for the BSD of the three Ne systems is calculated, comprising fusion-fission σ ff and deep inelastic scattering/orbiting σorb contributions (evaluated empirically here) from compound nucleus CN and non-compound nucleus nCN processes, respectively. The significant observation from this study is that, of the total σ BSD DCM , σ ff contribution is very strong for the decay of 20 Ne (=195.270 mb; >70%), followed by 21 Ne (=65.723 mb; ∼50%) and 22 Ne (=8.677 mb; almost 10%). This means that the process of collective clusterization within the DCM is playing very strong role for the decay of 20 Ne

Decay Time Measurement for Different Energy Depositions of Plastic Scintillator Fabricated by High Temperature Polymerization Reaction

Energy Technology Data Exchange (ETDEWEB)

Lee, Cheol Ho; Son, Jaebum; Lee, Sangmin; Kim, Tae Hoon; Kim, Yong-Kyun [Hanyang University, Seoul (Korea, Republic of)

2016-10-15

Plastic scintillators are based on organic fluorite. They have many advantages such as fast rise and decay time, high optical transmission, ease of manufacturing, low cost, and large available size. For these reasons they are widely used for particle identification. Also, protection of people against a variety of threats (such as nuclear, radiological, and explosive) represents a true challenge along with the continuing development of science and technology. The plastic scintillator is widely used in various devise, which serves for nuclear, photonics, quantum, and high-energy physics. The plastic scintillator is probably the most widely used organic detector, and polystyrene is one of the most widely used materials in the making of the plastic scintillator detector. Thus, a styrene monomer as a solvent was used to fabricate the plastic scintillator by using high temperature polymerization reaction, and then the emission wavelength and the decay times for different energy depositions were measured by using the fabricated plastic scintillator. A plastic scintillator was fabricated to measure decay time for different energy depositions using the high temperature polymerization. Emission wavelength was measured of 426.05 nm to confirm a scintillator property using the spectrophotometer. Four gamma-ray sources (Cs-137, Co-60, Na-22, and Ba-133) were used to evaluate effect for decay time of different energy depositions. The average decay time of the fabricated plastic scintillator was measured to approximately 4.72 ns slightly higher more than commercial plastic scintillator. In future, light output and linearity will be measured to evaluate other property compared with the commercial scintillator.

Decay Time Measurement for Different Energy Depositions of Plastic Scintillator Fabricated by High Temperature Polymerization Reaction

International Nuclear Information System (INIS)

Lee, Cheol Ho; Son, Jaebum; Lee, Sangmin; Kim, Tae Hoon; Kim, Yong-Kyun

2016-01-01

Plastic scintillators are based on organic fluorite. They have many advantages such as fast rise and decay time, high optical transmission, ease of manufacturing, low cost, and large available size. For these reasons they are widely used for particle identification. Also, protection of people against a variety of threats (such as nuclear, radiological, and explosive) represents a true challenge along with the continuing development of science and technology. The plastic scintillator is widely used in various devise, which serves for nuclear, photonics, quantum, and high-energy physics. The plastic scintillator is probably the most widely used organic detector, and polystyrene is one of the most widely used materials in the making of the plastic scintillator detector. Thus, a styrene monomer as a solvent was used to fabricate the plastic scintillator by using high temperature polymerization reaction, and then the emission wavelength and the decay times for different energy depositions were measured by using the fabricated plastic scintillator. A plastic scintillator was fabricated to measure decay time for different energy depositions using the high temperature polymerization. Emission wavelength was measured of 426.05 nm to confirm a scintillator property using the spectrophotometer. Four gamma-ray sources (Cs-137, Co-60, Na-22, and Ba-133) were used to evaluate effect for decay time of different energy depositions. The average decay time of the fabricated plastic scintillator was measured to approximately 4.72 ns slightly higher more than commercial plastic scintillator. In future, light output and linearity will be measured to evaluate other property compared with the commercial scintillator

Angular and velocity analysis of the three-fold events in the Xe+Cu reaction at 45 MeV/u

International Nuclear Information System (INIS)

Bruno, M.; D'Agostino, M.; Fiandri, M.L.; Fuschini, E.; Manduci, L.; Mastinu, P.F.; Milazzo, P.M.; Gramegna, F.; Ferrero, A.M.J.; Gulminelli, F.; Iori, I.; Moroni, A.; Scardaoni, R.; Buttazzo, P.; Margagliotti, G.V.; Vannini, G.; Auger, G.; Plagnol, E.

1994-01-01

An analysis of the angular and velocity distributions of the intermediate mass fragments produced in the reaction Xe+Cu at 45 MeV/u is presented. Events coming from central collisions are selected and compared with predictions of different models based on a statistical deexcitation of an equilibrated source. The angular and velocity correlations show that the experimental production of three nearly-equal mass fragments cannot be explained by a sequential binary decay and is compatible with a multifragmentation mechanism. ((orig.))

On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

Science.gov (United States)

Miller, R. S.; Bellan, J.

1997-01-01

An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

Gamma rays as probe of fission and quasi-fission dynamics in the reaction 32S + 197Au near the Coulomb barrier

Science.gov (United States)

Pulcini, A.; Vardaci, E.; Kozulin, E.; Ashaduzzaman, M.; Borcea, C.; Bracco, A.; Brambilla, S.; Calinescu, S.; Camera, F.; Ciemala, M.; de Canditiis, B.; Dorvaux, O.; Harca, I. M.; Itkis, I.; Kirakosyan, V. V.; Knyazheva, G.; Kozulina, N.; Kolesov, I. V.; La Rana, G.; Maj, A.; Matea, I.; Novikov, K.; Petrone, C.; Quero, D.; Rath, P.; Saveleva, E.; Schmitt, C.; Sposito, G.; Stezowski, O.; Trzaska, W. H.; Wilson, J.

2018-05-01

Compound nucleus fission and quasi-fission are both binary decay channels whose common properties make the experimental separation between them difficult. A way to achieve this separation could be to probe the angular momentum of the binary fragments. This can be done detecting gamma rays in coincidence with the two fragments. As a case study, the reaction 32S + 197Au near the Coulomb barrier has been performed at the Tandem ALTO facility at IPN ORSAY. ORGAM and PARIS, two different gamma detectors arrays, are coupled with the CORSET detector, a two-arm time-of-flight spectrometer. TOF-TOF data were analyzed to reconstruct the mass-energy distribution of the primary fragments coupled with gamma multiplicity and spectroscopic analysis. Preliminary results of will be shown.

Weak radiative hyperon decays

International Nuclear Information System (INIS)

Roberts, B.L.; Booth, E.C.; Gall, K.P.; McIntyre, E.K.; Miller, J.P.; Whitehouse, D.A.; Bassalleck, B.; Hall, J.R.; Larson, K.D.; Wolfe, D.M.; Fickinger, W.J.; Robinson, D.K.; Hallin, A.L.; Hasinoff, M.D.; Measday, D.F.; Noble, A.J.; Waltham, C.E.; Hessey, N.P.; Lowe, J.; Horvath, D.; Salomon, M.

1990-01-01

New measurements of the Σ + and Λ weak radiative decays are discussed. The hyperons were produced at rest by the reaction K - p → Yπ where Y = Σ + or Λ. The monoenergetic pion was used to tag the hyperon production, and the branching ratios were determined from the relative amplitudes of Σ + → pγ to Σ + → pπ 0 and Λ → nγ to Λ → nπ 0 . The photons from weak radiative decays and from π 0 decays were detected with modular NaI arrays. (orig.)

Three-body correlations in the decay of {sup 10}He and {sup 13}Li

Energy Technology Data Exchange (ETDEWEB)

Johansson, H.T. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Aksyutina, Yu. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); ExtreMe Matter Institute, EMMI, GSI, D-64291 Darmstadt (Germany); Aumann, T.; Boretzky, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Borge, M.J.G. [Instituto Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Chatillon, A. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Chulkov, L.V. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Kurchatov Institute, RU-123182 Moscow (Russian Federation); Cortina-Gil, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); University of Santiago de Compostela, 15706 Santiago de Compostela (Spain); Datta Pramanik, U. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Emling, H. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Forssen, C. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Fynbo, H.O.U. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Geissel, H.; Ickert, G. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Jonson, B., E-mail: Bjorn.Jonson@chalmers.s [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); Physics Department, CERN, CH-1211 Geneve 23 (Switzerland); Kulessa, R. [Instytut Fizyki, Universytet Jagiellonski, PL-30-059 Krakow (Poland); Langer, C. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Lantz, M. [Fundamental Fysik, Chalmers Tekniska Hoegskola, S-412 96 Goeteborg (Sweden); LeBleis, T.; Mahata, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

2010-12-01

The very exotic nuclear resonance systems, {sup 10}He and {sup 13}Li, are produced in proton-knockout reactions from relativistic beams of {sup 11}Li and {sup 14}Be. The experimentally determined energy and angular correlations between their decay products, {sup 8}He+n+n and {sup 11}Li+n+n, are analyzed using an expansion of decay amplitudes in a restricted set of hyperspherical harmonics. By considering only a small number of terms it is possible to extract the expansion coefficients directly from the experimental three-body correlations. This provides a model-independent way of getting information about the decay process, on the structure of the decaying nucleus and on the quantum characteristics of the binary subsystems. The results show that the {sup 8}He+n+n relative-energy spectrum can be interpreted as consisting of two resonances, an I{sup {pi}=}0{sup +} ground state and an excited I{sup {pi}=}2{sup +} state. The {sup 11}Li+n+n relative-energy spectrum is interpreted as an I{sup {pi}=}3/2{sup -} ground state overlapping with excited states having a structure similar to the 2{sup +} state in {sup 10}He but spread over several states due to the coupling to the I{sup {pi}=}3/2{sup -} core. The {sup 13}Li data also give evidence for a contribution of a configuration where the two neutrons occupy the d-shell.

The weak decay of helium hypernuclei

International Nuclear Information System (INIS)

Athanas, M.J.

1992-08-01

A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the A X(K - , π - ) Λ A X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ - ) and Γ(Λ → nπ 0 ) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (∼ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ - ), Γ(Λ → nπ 0 ) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI =1/2 rule. The hypernuclear state is isolated by momentum analysis of (K - , π - ) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for Λ 4 He

Bs mesons: semileptonic and nonleptonic decays

Directory of Open Access Journals (Sweden)

Albertus C.

2014-01-01

Full Text Available In this contribution we compute some nonleptonic and semileptonic decay widths of Bs mesons, working in the context of constituent quark models [1, 2]. For the case of semileptonic decays we consider reactions leading to kaons or different Jπ Ds mesons. The study of nonleptonic decays has been done in the factorisation approximation and includes the final states enclosed in Table 2.

The weak decay of helium hypernuclei

Energy Technology Data Exchange (ETDEWEB)

Athanas, Michael J. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)

1992-08-01

A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the ^AX(K^-, π^-) $A\\atop{Λ}$X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ^-) and Γ(Λ → nπ⁰) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (~ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ^-), Γ(Λ → nπ⁰) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI ={1/2} rule. The hypernuclear state is isolated by momentum analysis of (K^-, π^-) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for $4\\atop{Λ}$He.

Synthesis and decay process of superheavy nuclei with Z=119-122 via hot-fusion reactions

Energy Technology Data Exchange (ETDEWEB)

Ghahramany, N.; Ansari, A. [Shiraz University, Department of Physics and Biruni Observatory, College of Science, Shiraz (Iran, Islamic Republic of)

2016-09-15

In this research article attempts have been made to calculate the superheavy-nuclei synthesis characteristics including, the potential energy parameters, fusion probability, fusion and evaporation residue (ER) cross sections as well as, decay properties of compound nucleus and the residue nuclei formation probability for elements with Z=119-122 by using the hot-fusion reactions. It is concluded that, although a selection of double magic projectiles such as {sup 48}Ca with high binding energy, simplifies the calculations significantly due to spherical symmetric shape of the projectile, resulting in high evaporation residue cross section, unfortunately, nuclei with Z > 98 do not exist in quantities sufficient for constructing targets for the hot-fusion reactions. Therefore, practically our selection is fusion reactions with titanium projectile because the mass production of target nuclei for experimental purposes is more feasible. Based upon our findings, it is necessary, for new superheavy-nuclei production with Z > 119, to use neutron-rich projectiles and target nuclei. Finally, the maximal evaporation residue cross sections for the synthesis of superheavy elements with Z=119-122 have been calculated and compared with the previously founded ones in the literature. (orig.)

Hadronic model for the non-thermal radiation from the binary system AR Scorpii

Science.gov (United States)

Bednarek, W.

2018-05-01

AR Scorpii is a close binary system containing a rotation powered white dwarf and a low-mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure hadronic models for the high energy non-thermal processes in this binary system. Relativistic electrons and hadrons are assumed to be accelerated in a strongly magnetised, turbulent region formed in collision of a rotating white dwarf magnetosphere and a magnetosphere/dense atmosphere of the M-dwarf star. We propose that the non-thermal X-ray emission is produced either by the primary electrons or the secondary e± pairs from decay of charged pions created in collisions of hadrons with the companion star atmosphere. We show that the accompanying γ-ray emission from decay of neutral pions, which are produced by these same protons, is expected to be on the detectability level of the present and/or the future satellite and Cherenkov telescopes. The γ-ray observations of the binary system AR Sco should allow us to constrain the efficiency of hadron and electron acceleration and also the details of the radiation processes.

Decay rate ratios of Υ(5S)→B anti B reactions

International Nuclear Information System (INIS)

Hwang, Dae Sung; Son, Hyungsuk

2010-01-01

We calculate the decay rate ratios for OZI allowed decays of Υ(5S) to two B mesons by using the decay amplitudes which incorporate the wave function of the Υ(5S) state. We obtain the result that the branching ratio of the Υ(5S) decay to B s * anti B s * is much larger than the branching ratio to B s anti B s * or anti B s B s * , in good agreement with the recent experimental results of CLEO and BELLE. This agreement with the experimental results is made possible since the nodes of the Υ(5S) radial wave function induce the nodes of the decay amplitude. We find that the results for the Υ(5S) decays to B u (*) anti B u (*) or B d (*) anti B d (*) pairs are sensitive to the parameter values used for the potential between heavy quarks. (orig.)

Facile synthesis of pyrite-type binary nickel iron diselenides as efficient electrocatalyst for oxygen evolution reaction

Energy Technology Data Exchange (ETDEWEB)

Chi, Jing-Qi; Shang, Xiao [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liang, Fei [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Dong, Bin, E-mail: dongbin@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Li, Xiao; Liu, Yan-Ru; Yan, Kai-Li [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Gao, Wen-Kun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); College of Science, China University of Petroleum (East China), Qingdao 266580 (China); Chai, Yong-Ming [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China); Liu, Chen-Guang, E-mail: cgliu@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580 (China)

2017-04-15

Highlights: • Binary pyrite-type Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}/CFC was prepared by a facile two-step process. • The effect of Ni/Fe (Ni{sub x}Fe{sub 1-x}Se{sub 2} x = 0, 0.2, 0.5, 0.8, 1) on OER was investigated. • Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}/CFC (x = 0.5) possesses the better electrocatalytic activity for OER. • The enhanced activity may be attributed to binary Ni{sub 0.5}Fe{sub 0.5}Se{sub 2} and CFC support. - Abstract: Pyrite-type binary nickel iron diselenides (Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}) supported on carbon fiber cloth (CFC) as electrocatalysts for oxygen evolution reaction (OER) have been prepared by a facile two-step process. Firstly, binary Ni{sub 0.5}Fe{sub 0.5} hydroxide nanosheets have been electrodeposited on CFC. Secondly, a solvothermal selenization process has been used to convert Ni{sub 0.5}Fe{sub 0.5}/CFC into Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}/CFC. XRD shows that Ni{sub 0.5}Fe{sub 0.5}Se{sub 2} on CFC has the typically octahedral crystalline. XPS proves the existence and valence of Ni, Fe and Se. SEM images show that Ni{sub 0.5}Fe{sub 0.5}Se{sub 2} has novel pyrite-type octahedral morphology with uniform size and good dispersion on the surface of CFC. SEM elemental mapping images confirm the good distribution of Ni, Fe, Se element on CFC. TEM and SAED provide the clear diffraction rings of octahedral Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}, which is consistent with the results of XRD. Furtherly, the effect of different ratio of Ni/Fe (Ni{sub x}Fe{sub 1-x}Se{sub 2} x = 0, 0.2, 0.5, 0.8, 1) on OER performances has been systematically investigated. The electrochemical measurements results show that Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}/CFC (x = 0.5) possesses the better electrocatalytic activity with the lower overpotential, Tafel slope and long-term stability than other samples. The enhanced activity of Ni{sub 0.5}Fe{sub 0.5}Se{sub 2}/CFC may be attributed to the intrinsic activity of binary Ni{sub 0.5}Fe{sub 0.5}Se{sub 2} and faster electron

Study of the dissipative binary channels in the {sup 107}Ag + {sup 58}Ni reaction at 52 MeV/nucleon

Energy Technology Data Exchange (ETDEWEB)

Steckmeyer, J.C. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Aiello, S. [Catania Univ., INFN (Italy); Anzalone, A. [Catania Univ., LNS (Italy)] [and others

2002-03-01

The binary dissipative channels are characterized by the presence of two main fragments in the exit channel. They have been studied in the {sup 107}Ag+{sup 58}Ni reaction at 52 MeV/nucleon of bombarding energy. For that purpose a modified version of the Indra multidetector has been used in conjunction with a part of the Chimera multidetector. Preliminary results on the excitation energy and intrinsic angular momentum of the quasi-projectile are reported and compared to a dynamical calculation. (authors)

Decay of 57Ni

International Nuclear Information System (INIS)

Santos Scardino, A.M. dos.

1987-01-01

The decay of 57 Ni to 57 Co was studied by gamma ray spectroscopy using both singles and coincidence spectra. The sources were obtained with the 58 Ni (Y,n) 57 Ni reaction. Natural metallic nickel was irradiated in the bremsstrahluhng beam of the linear accelerator of the Instituto de Fisica da Universidade de Sao Paulo with 30 MeV electrons. The singles espectra were taken with 104 cc HPGe detector and the coincidences espectra with 27 and 53cc Ge(Li) and 104 cc. HPGe detectors. The energies of transitions that follow the 57 Ni decay were measured using 56 Co as standard (which was obtained by (Y,np) reaction in 58 Ni) and taking into account the cascade cross-over relations. (author) [pt

Special features of the inverse-beta-decay reaction proceeding on a proton in a reactor-antineutrino flux

Energy Technology Data Exchange (ETDEWEB)

Kopeikin, V. I., E-mail: kopeikin46@yandex.ru; Skorokhvatov, M. D., E-mail: skorokhvatov-md@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

2017-03-15

The evolution of the reactor-antineutrino spectrum and the evolution of the spectrum of positrons from the inverse-beta-decay reaction in the course of reactor operation and after reactor shutdown are considered. The present-day status in determining the initial reactor-antineutrino spectrum on the basis of spectra of beta particles from mixtures of products originating from uranium and plutonium fission is described. A local rise of the experimental spectrum of reactor antineutrinos with respect to the expected spectrum is studied.

Probing the N = Z Line via β Decay

International Nuclear Information System (INIS)

Markku Oinonen

1999-01-01

This contribution reports several beta-decay studies performed at ISOLDE On-Line Mass Separator at CERN recently for nuclei close to N = Z line. Beta decay of 58 Zn provides a possibility to compare Gamow-Teller strength extracted from complementary beta-decay studies and charge-exchange reactions. Measurement on beta-decay half-life of 70 Kr shows importance of experimental information in modeling the path of the astrophysical rp process. Decay of 71 Kr is an example of a mirror beta decay and extends the systematics of these particular decays towards highly deformed region close to A = 80

Energy dissipation in the process of ternary fission in heavy nuclear reaction

International Nuclear Information System (INIS)

Li Xian; Wang Chengqian; Yan Shiwei

2015-01-01

We studied the evolution of the collective motion, interaction potential, the total kinetic and excitation energies in ternary fissions of 197 Au + 197 Au system at 15 MeV/u, and discussed energy dissipation of this reaction. Through the comparison with energy-angle correlation data in binary fissions, we preliminarily concluded that the rst fission of ternary fission was an extreme deep-inelastic process. We further analyzed the correlation of the total kinetic energy with impact parameters in both binary and ternary reactions, and found that the total energy of binary reactions systems was lost about 150 MeV more than ternary fission with small impact parameters, and with larger impact parameters the total energy of ternary reactions were lost 300 MeV more than binary reactions. (authors)

The birth of a supermassive black hole binary

Science.gov (United States)

Pfister, Hugo; Lupi, Alessandro; Capelo, Pedro R.; Volonteri, Marta; Bellovary, Jillian M.; Dotti, Massimo

2017-11-01

We study the dynamical evolution of supermassive black holes, in the late stage of galaxy mergers, from kpc to pc scales. In particular, we capture the formation of the binary, a necessary step before the final coalescence, and trace back the main processes causing the decay of the orbit. We use hydrodynamical simulations of galaxy mergers with different resolutions, from 20 pc down to 1 pc, in order to study the effects of the resolution on our results, remove numerical effects, and assess that resolving the influence radius of the orbiting black hole is a minimum condition to fully capture the formation of the binary. Our simulations include the relevant physical processes, namely star formation, supernova feedback, accretion on to the black holes and the ensuing feedback. We find that, in these mergers, dynamical friction from the smooth stellar component of the nucleus is the main process that drives black holes from kpc to pc scales. Gas does not play a crucial role and even clumps do not induce scattering or perturb the orbits. We compare the time needed for the formation of the binary to analytical predictions and suggest how to apply such analytical formalism to obtain estimates of binary formation times in lower resolution simulations.

First Accurate Normalization of the $\\beta$-delayed $\\alpha$ Decay of $^{16}$N and Implications for the $^{12}$C$(\\alpha,\\gamma)^{16}$O Astrophysical Reaction Rate arXiv

CERN Document Server

Kirsebom, O.S.; Lica, R.; Munch, M.; Riisager, K.; Fynbo, H.O.U.; Borge, M.J.G.; Madurga, M.; Marroquin, I.; Andreyev, A.N.; Berry, T.A.; Christensen, E.R.; Fernández, P. Díaz; Doherty, D.T.; Van Duppen, P.; Fraile, L.M.; Gallardo, M.C.; Greenlees, P.T.; Harkness-Brennan, L.J.; Hubbard, N.; Huyse, M.; Jensen, J.H.; Johansson, H.; Jonson, B.; Judson, D.S.; Konki, J.; Lazarus, I.; Lund, M.V.; Marginean, N.; Marginean, R.; Perea, A.; Mihai, C.; Negret, A.; Page, R.D.; Pucknell, V.; Rahkila, P.; Sorlin, O.; Sotty, C.; Swartz, J.A.; Sørensen, H.B.; Törnqvist, H.; Vedia, V.; Warr, N.; De Witte, H.

The $^{12}$C$(\\alpha,\\gamma)^{16}$O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced $\\alpha$ width, $\\gamma_{11}$, of the bound $1^-$ level in $^{16}$O is particularly important to determine the cross section. The magnitude of $\\gamma_{11}$ is determined via sub-Coulomb $\\alpha$-transfer reactions or the $\\beta$-delayed $\\alpha$ decay of $^{16}$N, but the latter approach is presently hampered by the lack of sufficiently precise data on the $\\beta$-decay branching ratios. Here we report improved branching ratios for the bound $1^-$ level and for $\\beta$-delayed $\\alpha$ emission. In the case of the $\\beta$-delayed $\\alpha$ branch, we find a $5\\sigma$ deviation from the literature value. With our new branching ratios, the constraints imposed on $\\gamma_{11}$ by the $\\beta\\alpha$-decay and $\\alpha$-transfer data are of similar precision and, for the first time, in good agreement. Th...

Levels in 223Th populated by α decay of 227U

Science.gov (United States)

Kalaninová, Z.; Antalic, S.; Heßberger, F. P.; Ackermann, D.; Andel, B.; Kindler, B.; Laatiaoui, M.; Lommel, B.; Maurer, J.

2015-07-01

Levels in 223Th populated by the α decay of 227U were investigated using α -γ decay spectroscopy. The 227U isotope was produced in the fusion-evaporation reaction 22Ne +208Pb at the velocity filter separator for heavy-ion reaction products at Gesellschaft für Schwerionenforschung in Darmstadt (Germany). Several new excited levels and γ transitions were identified in 223Th . An improved α -decay scheme of 227U was suggested. The experimental α -decay energy spectrum of 227U was compared with the Monte Carlo simulation performed using the toolkit geant4.

Rare muon decays and lepton-family number conservation

International Nuclear Information System (INIS)

Hoffman, C.M.

1984-04-01

A brief historical survey of the discovery of the muon, interest in neutrinoless processes, and lepton-number conservation laws is given. The present view of lepton-number conservation laws and the search for μ → eγ are described. Other experiments are discussed including μ + → e + e + e - decay, μ - Z → e - Z reactions, μ → e γγ decay, other rare muon processes, strangeness-changing muon-number-nonconserving decays, and tau decays. 52 references

Probing reaction dynamics with GDR decay

International Nuclear Information System (INIS)

Beene, J.R.

1994-01-01

The giant dipole resonance (GDR) has been a prolific source of information on the physics of the nucleus. Mostly it has taught us about nuclear structure, but recently experiments have utilized the GDR as a probe of nuclear reaction dynamics. In this report two examples of such investigations are discussed involving very different reactions and probing time scales that differ by a factor of ∼10 3

Spectroscopy of element 115 decay chains

Energy Technology Data Exchange (ETDEWEB)

Rudolph, Dirk [Lund University, Sweden; Forsberg, U. [Lund University, Sweden; Golubev, P. [Lund University, Sweden; Sarmiento, L. G. [Lund University, Sweden; Yakushev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Andersson, L.-L. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Di Nitto, A. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Duehllmann, Ch. E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Gates, J. M. [Lawrence Berkeley National Laboratory (LBNL); Gregorich, K. E. [Lawrence Berkeley National Laboratory (LBNL); Gross, Carl J [ORNL; Hessberger, F. P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Herzberg, R.-D [University of Liverpool; Khuyagbaatar, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, J. V. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Rykaczewski, Krzysztof Piotr [ORNL; Schaedel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Aberg, S. [Lund University, Sweden; Ackermann, D. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Block, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brand, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Carlsson, B. G. [Lund University, Sweden; Cox, D. [University of Liverpool; Derkx, X. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Eberhardt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Even, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Fahlander, C. [Lund University, Sweden; Gerl, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Jaeger, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kindler, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Krier, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kojouharov, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kurz, N. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Lommel, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mistry, A. [University of Liverpool; Mokry, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Nitsche, H. [Lawrence Berkeley National Laboratory (LBNL); Omtvedt, J. P. [Paul Scherrer Institut, Villigen, Switzerland; Papadakis, P. [University of Liverpool; Ragnarsson, I. [Lund University, Sweden; Runke, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schaffner, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schausten, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Thoerle-Pospiech, P. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Torres, T. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Traut, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Tuerler, A. [Paul Scherrer Institut, Villigen, Switzerland; Ward, A. [University of Liverpool; Ward, D. E. [Lund University, Sweden; Wiehl, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany

2013-01-01

A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state

Science.gov (United States)

Vick, Michelle; Lai, Dong

2018-05-01

Highly eccentric binary systems appear in many astrophysical contexts, ranging from tidal capture in dense star clusters, precursors of stellar disruption by massive black holes, to high-eccentricity migration of giant planets. In a highly eccentric binary, the tidal potential of one body can excite oscillatory modes in the other during a pericentre passage, resulting in energy exchange between the modes and the binary orbit. These modes exhibit one of three behaviours over multiple passages: low-amplitude oscillations, large-amplitude oscillations corresponding to a resonance between the orbital frequency and the mode frequency, and chaotic growth, with the mode energy reaching a level comparable to the orbital binding energy. We study these phenomena with an iterative map that includes mode dissipation, fully exploring how the mode evolution depends on the orbital and mode properties of the system. The dissipation of mode energy drives the system towards a quasi-steady state, with gradual orbital decay punctuated by resonances. We quantify the quasi-steady state and the long-term evolution of the system. A newly captured star around a black hole can experience significant orbital decay and heating due to the chaotic growth of the mode amplitude and dissipation. A giant planet pushed into a high-eccentricity orbit may experience a similar effect and become a hot or warm Jupiter.

Spectroscopy of element 115 decay chains.

Science.gov (United States)

Rudolph, D; Forsberg, U; Golubev, P; Sarmiento, L G; Yakushev, A; Andersson, L-L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Gregorich, K E; Gross, C J; Heßberger, F P; Herzberg, R-D; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Schädel, M; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

2013-09-13

A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Evidence for the di-triton resonance in 6He

International Nuclear Information System (INIS)

Akimune, H.; Yamagata, T.; Nakayama, S.

2002-01-01

A di-triton cluster state at highly excited energies in 6 He has been investigated via the ( 7 Li, 7 Be) reaction with an incident energy of 65 MeV/A. Decay charged-particles from excited states in 6 He were measured in coincidence with 7 Be ejectiles using solid-state detectors. A prominent bump was observed at E x =18 MeV in the binary triton decay channel. The branching ratio of the binary triton decay channel from this bump was 100% based on the spectrum decomposition analysis. (author)

Anomalous relaxation in binary mixtures: a dynamic facilitation picture

International Nuclear Information System (INIS)

Moreno, A J; Colmenero, J

2007-01-01

Recent computational investigations of polymeric and non-polymeric binary mixtures have reported anomalous relaxation features when both components exhibit very different mobilities. Anomalous relaxation is characterized by sublinear power-law behaviour for mean-squared displacements, logarithmic decay in dynamic correlators, and a striking concave-to-convex crossover in the latter by tuning the relevant control parameter, in analogy with predictions of the mode-coupling theory for state points close to higher-order transitions. We present Monte Carlo simulations on a coarse-grained model for relaxation in binary mixtures. The liquid structure is substituted by a three-dimensional array of cells. A spin variable is assigned to each cell, representing unexcited and excited local states of a mobility field. Changes in local mobility (spin flip) are permitted according to kinetic constraints determined by the mobilities of the neighbouring cells. We introduce two types of cell ('fast' and 'slow') with very different rates for spin flip. This coarse-grained model qualitatively reproduces the mentioned anomalous relaxation features observed for real binary mixtures

The 49K beta decay

International Nuclear Information System (INIS)

Hansen, P.G.; Huck, A.; Klotz, G.; Knipper, A.; Miehe, C.; Walter, G.; Jonson, B.; Mattsson, S.; Ravn, H.L.; Kratz, K.L.

1981-01-01

The decay of 49 K has been studied through neutron and gamma spectroscopy techniques. The 49 K activity was formed by 600 MeV proton fragmentation reactions in a uranium carbide target. The observed β-strength, in addition to the general behaviour expected from the gross theory of β-decay, displays two resonances centered at about 6.5 MeV and 9.5 MeV in 49 Ca. This structure is discussed in simple shell-model terms. (orig.)

Binary and tertiary reaction cross-sections of V, Cr, Mn, Fe, Ni, Cu, Zr, Nb, Mo, Ta, W, Pt and their isotopes

International Nuclear Information System (INIS)

Garg, S.B.

1982-01-01

Neutron induced binary and tertiary reaction cross-sections have been evaluated for V, Cr, Mn, Fe, Ni, Cu, Zr, Nb, Mo, Ta, W, Pt and their isotopes in the 'energy range 0.5 MeV to 20 MeV using the nuclear statistical empirical model. The reactions considered are (n,n'), (n,2n), (n,3n), (n,p), (n,d), (n,t), (n, 3 He), (n,α), (n,np), (n,nd), (n,nt), (n,n 3 He), (n,nα), (n,pn), (n,2p), (n,ν), (n,αp), (n,dn) and (n,pα). Most of the above mentioned elements are used as structural materials in nuclear reactors and the measured cross-section data for the above listed reactions are seldom available for the radiation damage and safety analysis. With a view to providing these data, this nuclear model based evaluation has been undertaken. The associated uncertainties in the cross-sections and their fission averages have also been evaluated. (author)

Modeling of formation of binary-phase hollow nanospheres from metallic solid nanospheres

International Nuclear Information System (INIS)

Svoboda, J.; Fischer, F.D.; Vollath, D.

2009-01-01

Spontaneous formation of binary-phase hollow nanospheres by reaction of a metallic nanosphere with a non-metallic component in the surrounding atmosphere is observed for many systems. The kinetic model describing this phenomenon is derived by application of the thermodynamic extremal principle. The necessary condition of formation of the binary-phase hollow nanospheres is that the diffusion coefficient of the metallic component in the binary phase is higher than that of the non-metallic component (Kirkendall effect occurs in the correct direction). The model predictions of the time to formation of the binary-phase hollow nanospheres agree with the experimental observations

Proton transfer and unimolecular decay in the low-energy-reaction dynamics of H3O+ with acetone

International Nuclear Information System (INIS)

Creasy, W.R.; Farrar, J.M.

1983-01-01

The title reaction has been studied at collision energies of 0.83 and 2.41 eV. Direct reaction dynamics have been observed at both energies and an increasingly high fraction of the total energy appears in product translation as the collision energy increases. This result is consistent with the concept of induced repulsive energy release, which becomes more effective as trajectories sample the corner of the potential energy surface. At the higher collision energy, the protonated acetone cation undergoes two unimolecular decay channels: C-C bond cleavage to CH 3 CO + and CH 4 , and C-O bond cleavagto C 3 H 5 + (presumably to allyl cation) and H 2 O. The CH 3 CO + channel, endothermic relative to ground state protonated acetone cations by 0.74 eV, appears to liberate 0.4 eV in relative product translation while the C 3 H 5 + channel, endothermic by 2.17 eV, liberates only 0.07 eV in relative translation. These results are discussed in terms of the location on the reaction coordinate and magnitudes of potential energy barriers to 1,3-hydrogen atoms shifts which must precede the bond cleavage processes

Identifying decaying supermassive black hole binaries from their variable electromagnetic emission

Energy Technology Data Exchange (ETDEWEB)

Haiman, Zoltan; Menou, Kristen [Department of Astronomy, Columbia University, New York, NY (United States); Kocsis, Bence [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Lippai, Zoltan; Frei, Zsolt [Institute of Physics, Eoetvoes University, Budapest (Hungary)

2009-05-07

Supermassive black hole binaries (SMBHBs) with masses in the mass range approx(10{sup 4}-10{sup 7}) M{sub o-dot}/(1 + z), produced in galaxy mergers, are thought to complete their coalescence due to the emission of gravitational waves (GWs). The anticipated detection of the GWs by the future Laser Interferometric Space Antenna (LISA) will constitute a milestone for fundamental physics and astrophysics. While the GW signatures themselves will provide a treasure trove of information, if the source can be securely identified in electromagnetic (EM) bands, this would open up entirely new scientific opportunities, to probe fundamental physics, astrophysics and cosmology. We discuss several ideas, involving wide-field telescopes, that may be useful in locating electromagnetic counterparts to SMBHBs detected by LISA. In particular, the binary may produce a variable electromagnetic flux, such as a roughly periodic signal due to the orbital motion prior to coalescence, or a prompt transient signal caused by shocks in the circumbinary disc when the SMBHB recoils and 'shakes' the disc. We discuss whether these time-variable EM signatures may be detectable, and how they can help in identifying a unique counterpart within the localization errors provided by LISA. We also discuss a possibility of identifying a population of coalescing SMBHBs statistically, in a deep optical survey for periodically variable sources, before LISA detects the GWs directly. The discovery of such sources would confirm that gas is present in the vicinity and is being perturbed by the SMBHB-serving as a proof of concept for eventually finding actual LISA counterparts.

Identifying decaying supermassive black hole binaries from their variable electromagnetic emission

International Nuclear Information System (INIS)

Haiman, Zoltan; Menou, Kristen; Kocsis, Bence; Lippai, Zoltan; Frei, Zsolt

2009-01-01

Supermassive black hole binaries (SMBHBs) with masses in the mass range ∼(10 4 -10 7 ) M o-dot /(1 + z), produced in galaxy mergers, are thought to complete their coalescence due to the emission of gravitational waves (GWs). The anticipated detection of the GWs by the future Laser Interferometric Space Antenna (LISA) will constitute a milestone for fundamental physics and astrophysics. While the GW signatures themselves will provide a treasure trove of information, if the source can be securely identified in electromagnetic (EM) bands, this would open up entirely new scientific opportunities, to probe fundamental physics, astrophysics and cosmology. We discuss several ideas, involving wide-field telescopes, that may be useful in locating electromagnetic counterparts to SMBHBs detected by LISA. In particular, the binary may produce a variable electromagnetic flux, such as a roughly periodic signal due to the orbital motion prior to coalescence, or a prompt transient signal caused by shocks in the circumbinary disc when the SMBHB recoils and 'shakes' the disc. We discuss whether these time-variable EM signatures may be detectable, and how they can help in identifying a unique counterpart within the localization errors provided by LISA. We also discuss a possibility of identifying a population of coalescing SMBHBs statistically, in a deep optical survey for periodically variable sources, before LISA detects the GWs directly. The discovery of such sources would confirm that gas is present in the vicinity and is being perturbed by the SMBHB-serving as a proof of concept for eventually finding actual LISA counterparts.

Application of atomic mutations included in nuclear reactions, 40Ar(γ, p)39Cl(β decay)39Ar, to surface study

International Nuclear Information System (INIS)

Ohkuma, Juzo

1987-01-01

It has been found that the nuclear transformation processes which are initiated by photonuclear reactions can be used for studying the adsorption and chemical reactions taking place on solid surfaces. Chemically reactive 39 Cl was produced by irradiating 40 Ar with high-energy bremsstrahlung, and its blow was directed onto several material surfaces. The amount of chlorine adsorption was ascertained by detecting its radioactivity. Desorption without heating the adsorber samples inevitably occurred owing to the nuclear decay of 39 Cl. The adsorption and desorption rates were compared for several elements. A fast growth of oxide islands on sample surfaces was observed during the adsorption-desorption process. (author)

Chlorine decay under steady and unsteady-state hydraulic conditions

DEFF Research Database (Denmark)

Stoianov, Ivan; Aisopou, Angeliki

2014-01-01

This paper describes a simulation framework for the scale-adaptive hydraulic and chlorine decay modelling under steady and unsteady-state flows. Bulk flow and pipe wall reaction coefficients are replaced with steady and unsteady-state reaction coefficients. An unsteady decay coefficient is defined...... which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. A preliminary experimental and analytical investigation was carried out in a water transmission main. The results were used to model monochloramine decay...... and these demonstrate that the dynamic hydraulic conditions have a significant impact on water quality deterioration and the rapid loss of disinfectant residual. © 2013 The Authors....

On Uniform Decay of the Entropy for Reaction–Diffusion Systems

KAUST Repository

Mielke, Alexander; Haskovec, Jan; Markowich, Peter A.

2014-01-01

This work provides entropy decay estimates for classes of nonlinear reaction–diffusion systems modeling reversible chemical reactions under the detailed-balance condition. We obtain explicit bounds for the exponential decay of the relative

Structure of β-decay strength functions

International Nuclear Information System (INIS)

Naumov, Y.V.; Bykov, A.A.; Izosimov, I.N.

1983-01-01

The experimental and theoretical studies on the structure of the Gamow--Teller β-decay strength functions are reviewed. Also considered are processes such as M1 γ decay of analog states, the emission of delayed protons, neutrons, and α particles, delayed fission, and the (p, n) reaction at proton energies 100--200 MeV. The results of measurements of the strength functions by γ-ray total absorption are analyzed. It is shown that the β + decay of nuclei far from the stability band exhibits a new type of collective charge-exchange excitation: Gamow--Teller resonance with μ/sub tau/ = +1

β-decay of 37Ca

International Nuclear Information System (INIS)

Trinder, W.; Adelberger, E.G.; Keller, H.; Krumbholz, K.; Rykaczewski, K.

1994-11-01

The β-decay of 37 Ca has been studied. The half-life was remeasured with improved precision to be 181(1) ms, and β-delayed γ-rays were observed for the first time. The surprisingly high Γ γ /Γ p values for proton-unbound states in 37 K drastically reduce former discrepancies between the Gamow-Teller strength values B(GT) measured in the 37 Ga β-decay and those deduced from the 37 Cl(p, n) 37 Ar mirror reaction. (orig.)

A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states

International Nuclear Information System (INIS)

Nguyen, Trong-Nghia; Putikam, Raghunath; Lin, M. C.

2015-01-01

We have discovered a new and highly competitive product channel in the unimolecular decay process for small Criegee intermediates, CH 2 OO and anti/syn-CH 3 C(H)OO, occurring by intramolecular insertion reactions via a roaming-like transition state (TS) based on quantum-chemical calculations. Our results show that in the decomposition of CH 2 OO and anti-CH 3 C(H)OO, the predominant paths directly produce cis-HC(O)OH and syn-CH 3 C(O)OH acids with >110 kcal/mol exothermicities via loose roaming-like insertion TSs involving the terminal O atom and the neighboring C–H bonds. For syn-CH 3 C(H)OO, the major decomposition channel occurs by abstraction of a H atom from the CH 3 group by the terminal O atom producing CH 2 C(H)O–OH. At 298 K, the intramolecular insertion process in CH 2 OO was found to be 600 times faster than the commonly assumed ring-closing reaction

Chemical aspects of the radioactive decay 38S to 38Cl

International Nuclear Information System (INIS)

Leurs, C.J.

1978-01-01

The cyclotron-production of 38 S with the reaction 40 Ar(p,3p) 38 S is described. An excitation curve for this nuclear reaction is given and the chemistry used to produce sulfates labeled with 38 S and H 2 38 S is described. The probability distribution of the recoil energy of 38 Cl, produced by beta-decay of 38 S, is given. The probability for rupture of the original bonds due to the radioactive decay process, is estimated for gaseous H 2 38 S and for crystalline sulfates- 38 S. The results are given for the β,γ-decay of 38 S to 38 Cl under different circumstances in inorganic solid sulfates (with and without water of crystallization) and in the mixed crystal K 2 SO 4 .K 2 BeF 4 (1 : 2500). Finally, the reactions of 38 Cl, produced by radioactive decay of 38 S (as H 2 38 S) with gaseous 1,2-dichloroethylene are discussed

Mathematical Simulation of High-Conversion Binary Copolymerization

Institute of Scientific and Technical Information of China (English)

JiangWei; QinJiguang

2005-01-01

A new model for mathematical simulation of high-conversion binary copolymerization was established by combination of the concept of the three stage polymerization model (TSPM) proposed by Qin et al. for bulk free radical homopolymerization with the North equation to describe high-conversion copolymerization reaction exhibiting a strong gel effect, and the mathematical expressions of this new model were derived. Like TSPM, the new model also assmnes that the whole course of binary copolymerization can be divided into three different stages: low conversion, gel effect and glass effect stages. In addition, the reaction rate constants and the initiator efficiency at each copolymerization stage do not vary with conversion. Based on the expressions derived, a plot method for determining the overall rate constants and critical conversions was proposed. The literature data on conversion history for styrene (St)-methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA)-MMA copolymerizations were treated to examine the model, which shows that the model is satisfactory.

Nuclear Structure Calculations for Two-Neutrino Double-β Decay

Directory of Open Access Journals (Sweden)

P. Sarriguren

2016-01-01

Full Text Available We study the two-neutrino double-β decay in 76Ge, 116Cd, 128Te, 130Te, and 150Nd, as well as the two Gamow-Teller branches that connect the double-β decay partners with the states in the intermediate nuclei. We use a theoretical microscopic approach based on a deformed self-consistent mean field with Skyrme interactions including pairing and spin-isospin residual forces, which are treated in a proton-neutron quasiparticle random-phase approximation. We compare our results for Gamow-Teller strength distributions with experimental information obtained from charge-exchange reactions. We also compare our results for the two-neutrino double-β decay nuclear matrix elements with those extracted from the measured half-lives. Both single-state and low-lying-state dominance hypotheses are analyzed theoretically and experimentally making use of recent data from charge-exchange reactions and β decay of the intermediate nuclei.

The V3+-V5+ redox equilibrium reaction and magnetic properties of vanadium ions in binary alkali silicate glasses

International Nuclear Information System (INIS)

Singh, R.S.; Singh, S.P.

2000-01-01

The oxidation-reduction equilibrium in binary alkali silicate glasses containing V 3+ , V 4+ and V 5+ ions was studied at 1400 degC in air atmosphere. The ionic equation representing the V 3+ -V 5+ redox equilibrium reaction was used to represent the V 3+ -V 4+ -V 5+ redox reactions in glasses as V 4+ ion was an intermediate species. The V 3+ -V 5+ redox equilibrium was found to shift more towards the oxidized state with the increasing ionic radii of alkali ions or with the increasing concentration of alkali oxide in the same series of glasses. The slopes of the straight lines obtained on plotting log ([V 5+ ]/[V 3+ ][pO 2 ] 1/2 ) against mol% R 2 O (R + = Li + , Na + and K + ions) in binary alkali silicate glasses were approximately inversely proportional to the coulombic force between the alkali ions and nonbridging oxygen ions. This indicates the redox equilibrium shifted more towards oxidized state with increasing oxygen ion activity in the glass. The loss of vanadium from the glass melts with the duration of heat treatment was observed due to volatilization at high temperature, which did not influence the V 3+ -V 5+ redox equilibrium. Magnetic susceptibility of the present glasses, measured at room temperature, did not show any sign of paramagnetism which might be due to the presence of smaller concentration of V 3+ and V 4+ ions in the glass. Further, it indicated a strong diamagnetism because of the presence of higher proportion of vanadium in pentavalent state in the glasses. However, the optical absorption spectra or a silicate glass containing ions of vanadium indicated the presence of V 3+ , V 4+ and V 5+ ions. (author)

Role of higher-multipole deformations and noncoplanarity in the decay of the compound nucleus *220Th within the dynamical cluster-decay model

Science.gov (United States)

Hemdeep, Chopra, Sahila; Kaur, Arshdeep; Kaushal, Pooja; Gupta, Raj K.

2018-04-01

Background: The formation and decay of the *220Th compound nucleus (CN) formed via some entrance channels (16O+204Pb,40Ar+180Hf,48Ca+172Yb,82Se+138Ba ) at near barrier energies has been studied within the dynamical cluster-decay model (DCM) [Hemdeep et al. Phys. Rev. C 95, 014609 (2017), 10.1103/PhysRevC.95.044603], for quadrupole deformations (β2 i) and "optimum" orientations (θopt) of the two nuclei or decay fragments lying in the same plane (coplanar nuclei, Φ =0∘ ). Purpose: We aim to investigate the role of higher-multipole deformations, the octupole (β3 i) and hexadecupole (β4 i), and "compact" orientations (θc i) together with the noncoplanarity degree of freedom (Φc) in the noncompound nucleus (nCN) cross section, already observed in the above mentioned study with quadrupole deformations (β2 i) alone, the Φ =0∘ case. Methods: The dynamical cluster-decay model (DCM), based on the quantum mechanical fragmentation theory (QMFT), is used to analyze the decay channel cross sections σx n for various experimentally studied entrance channels. The parameter Ra (equivalently, the neck length Δ R in Ra=R1+R2+Δ R ), which fixes both the preformation and penetration paths, is used to best fit both unobserved (1 n ,2 n ) and observed (3 n -5 n ) decay channel cross sections, keeping the root-mean-square (r.m.s) deviation to the minimum, which allows us to predict the nCN effects, if any, and fusion-fission (ff) cross sections in various reactions at different CN excitation energies E*. Results: For the decay of CN *220Th, the mass fragmentation potential V (Ai ) and preformation yields P0( Ai ) show an asymmetric fission mass distribution, in agreement with one observed in experiments, independent of adding or not adding (β3 i,β4 i ), and irrespective of large changes (by 36° and 34°), respectively, in "compact" orientations θc i and noncoplanarity Φc, and also in the potential energy surface V (Ai ) in light mass (1 n -5 n ) decays. Whereas the 3 n

Extrasolar binary planets. I. Formation by tidal capture during planet-planet scattering

International Nuclear Information System (INIS)

Ochiai, H.; Nagasawa, M.; Ida, S.

2014-01-01

We have investigated (1) the formation of gravitationally bounded pairs of gas-giant planets (which we call 'binary planets') from capturing each other through planet-planet dynamical tide during their close encounters and (2) the subsequent long-term orbital evolution due to planet-planet and planet-star quasi-static tides. For the initial evolution in phase 1, we carried out N-body simulations of the systems consisting of three Jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing, and this fraction is almost independent of the initial stellarcentric semimajor axes of the planets, while ejection and merging rates sensitively depend on the semimajor axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by long-term quasi-static tide. We analytically calculated the quasi-static tidal evolution in phase 2. The binary planets first enter the spin-orbit synchronous state by the planet-planet tide. The planet-star tide removes angular momentum of the binary motion, eventually resulting in a collision between the planets. However, we found that the binary planets survive the tidal decay for the main-sequence lifetime of solar-type stars (∼10 Gyr), if the binary planets are beyond ∼0.3 AU from the central stars. These results suggest that the binary planets can be detected by transit observations at ≳ 0.3 AU.

Sigma beta decay

International Nuclear Information System (INIS)

Newman, D.E.

1975-01-01

Describes an experiment to measure beta decays of the sigma particle. Sigmas produced by stopping a K - beam in a liquid hydrogen target decayed in the following reactions: Kp → Σπ; Σ → Neν. The electron and pion were detected by wire spark chambers in a magnetic spectrometer and by plastic scintillators, and were differentiated by a threshold gas Cherenkov counter. The neutron was detected by liquid scintillation counters. The data (n = 3) shell electrons or the highly excited electrons decay first. Instead, it is suggested that when there are two to five electrons in highly excited states immediately after a heavy ion--atom collision the first transitions to occur will be among highly excited Rydberg states in a cascade down to the 4s, 4p, and 3d-subshells. If one of the long lived states becomes occupied by electrons promoted during the collision or by electrons falling from higher levels, it will not decay until after the valence shell decays. LMM rates calculated to test the methods used are compared to previous works. The mixing coefficients are given in terms of the states 4s4p, 45sp+-, and 5s5p. The applicability of Cooper, Fano, and Prats' discussion of the energies and transition rates of doubly excited states is considered

J/psi and Υ radiative and hadronic decays

International Nuclear Information System (INIS)

Bloom, E.D.

1987-07-01

The search for gluonium at the J/psi and Υ is discussed, as well as the search for exotics at the Υ. Reactions discussed include radiative and hadronic decays of the J/psi and the search for radiative decays of the Υ. Future perspectives are also briefly considered. 45 refs., 27 figs

(EC+β+) decay of 130Ce

International Nuclear Information System (INIS)

Xu Shuwei; Zhang Tianmei; Xie Yuanxiang; Ma Ruichang; Ge Yuanxiu; Guo Yingxiang; Wang Chunfang; Li Zhankui; Guo Bing; Xing Jianping; Guo Tianrui; Zhu Shaofei; Xu Wang; Du Jinzhou

1996-01-01

The nuclide 130 Ce was produced by a ( 16 O, 4n) reaction on an enriched 118 Sn target. Reaction products were transported to a shielded location by using a helium-jet tape transport system. A 22.9 min activity in chemically separated cerium sample was identified as 130 Ce. The (EC+β + ) decay scheme of 130 Ce was proposed for the first time. This scheme includes 108 γ-lines, 107 γ-lines among them being new. More than 13 1 + low-lying states of 130 La are populated in the decay of 130 Ce. Two new isomers with half-life of 77±10 ns and 17±5 ns were observed by means of delayed γ-γ coincidence measurements. (orig.). With 5 figs., 3 tabs

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

Science.gov (United States)

Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

2012-02-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

International Nuclear Information System (INIS)

Trache, L; Banu, A; Hardy, J C; Iacob, V E; McCleskey, M; Roeder, B T; Simmons, E; Spiridon, A; Tribble, R E; Saastamoinen, A; Jokinen, A; Äysto, J; Davinson, T; Lotay, G; Woods, P J; Pollacco, E

2012-01-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A and M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23 Al, 27 P, 31 Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22 Na(p,γ) 23 Mg (crucial for the depletion of 22 Na in novae), 26m Al(p,γ) 27 Si and 30 P(p,γ) 31 S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Beta decay of polarized nuclei and the decay asymmetry of 8Li

International Nuclear Information System (INIS)

Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.

1985-01-01

Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li

The decay of hot nuclei

International Nuclear Information System (INIS)

Moretto, L.G.; Wozniak, G.J.

1988-11-01

The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs

Interacting binaries

International Nuclear Information System (INIS)

Eggleton, P.P.; Pringle, J.E.

1985-01-01

This volume contains 15 review articles in the field of binary stars. The subjects reviewed span considerably, from the shortest period of interacting binaries to the longest, symbiotic stars. Also included are articles on Algols, X-ray binaries and Wolf-Rayet stars (single and binary). Contents: Preface. List of Participants. Activity of Contact Binary Systems. Wolf-Rayet Stars and Binarity. Symbiotic Stars. Massive X-ray Binaries. Stars that go Hump in the Night: The SU UMa Stars. Interacting Binaries - Summing Up

Soot modeling of counterflow diffusion flames of ethylene-based binary mixture fuels

KAUST Repository

Wang, Yu; Raj, Abhijeet Dhayal; Chung, Suk-Ho

2015-01-01

of ethylene and its binary mixtures with methane, ethane and propane based on the method of moments. The soot model has 36 soot nucleation reactions from 8 PAH molecules including pyrene and larger PAHs. Soot surface growth reactions were based on a modified

Decay properties of high-lying single-particles modes

Science.gov (United States)

Beaumel, D.; Fortier, S.; Galès, S.; Guillot, J.; Langevin-Joliot, H.; Laurent, H.; Maison, J. M.; Vernotte, J.; Bordewijck, J.; Brandenburg, S.; Krasznahorkay, A.; Crawley, G. M.; Massolo, C. P.; Renteria, M.; Khendriche, A.

1996-02-01

The neutron decay of high-lying single-particle states in 64Ni, 90Zr, 120Sn and 208Pb excited by means of the (α, 3He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in 91Zr, and between 8 and 12 MeV excitation energy in 209Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations.

Multifractal scaling analysis of autopoisoning reactions over a rough surface

International Nuclear Information System (INIS)

Chaudhari, Ajay; Yan, Ching-Cher Sanders; Lee, S.-L.

2003-01-01

Decay type diffusion-limited reactions (DLR) over a rough surface generated by a random deposition model were performed. To study the effect of the decay profile on the reaction probability distribution (RPD), multifractal scaling analysis has been carried out. The dynamics of these autopoisoning reactions are controlled by the two parameters in the decay function, namely, the initial sticking probability (P ini ) of every site and the decay rate (m). The smaller the decay rate, the narrower is the range of α values in the α-f(α) multifractal spectrum. The results are compared with the earlier work of DLR over a surface of diffusion-limited aggregation (DLA). We also considered here the autopoisoning reactions over a smooth surface for comparing our results, which show clearly how the roughness affects the chemical reactions. The q-τ(q) multifractal curves for the smooth surface are linear whereas those for the rough surface are nonlinear. The range of α values in the case of a rough surface is wider than that of the smooth surface

The True Ultracool Binary Fraction Using Spectral Binaries

Science.gov (United States)

Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Schmidt, Sarah J.; Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle; Gelino, Chris

2018-01-01

Brown dwarfs bridge the gap between stars and giant planets. While the essential mechanisms governing their formation are not well constrained, binary statistics are a direct outcome of the formation process, and thus provide a means to test formation theories. Observational constraints on the brown dwarf binary fraction place it at 10 ‑ 20%, dominated by imaging studies (85% of systems) with the most common separation at 4 AU. This coincides with the resolution limit of state-of-the-art imaging techniques, suggesting that the binary fraction is underestimated. We have developed a separation-independent method to identify and characterize tightly-separated (dwarfs as spectral binaries by identifying traces of methane in the spectra of late-M and early-L dwarfs. Imaging follow-up of 17 spectral binaries yielded 3 (18%) resolved systems, corroborating the observed binary fraction, but 5 (29%) known binaries were missed, reinforcing the hypothesis that the short-separation systems are undercounted. In order to find the true binary fraction of brown dwarfs, we have compiled a volume-limited, spectroscopic sample of M7-L5 dwarfs and searched for T dwarf companions. In the 25 pc volume, 4 candidates were found, three of which are already confirmed, leading to a spectral binary fraction of 0.95 ± 0.50%, albeit for a specific combination of spectral types. To extract the true binary fraction and determine the biases of the spectral binary method, we have produced a binary population simulation based on different assumptions of the mass function, age distribution, evolutionary models and mass ratio distribution. Applying the correction fraction resulting from this method to the observed spectral binary fraction yields a true binary fraction of 27 ± 4%, which is roughly within 1σ of the binary fraction obtained from high resolution imaging studies, radial velocity and astrometric monitoring. This method can be extended to identify giant planet companions to young brown

gamma-decay of resonance-like structure observed in sup 3 sup 0 Si(p,gamma) sup 3 sup 1 P reaction

CERN Document Server

Kachan, A S; Korda, L P; Mishchenko, V M; Korda, V Y

2002-01-01

gamma-Decay of a resonance-like structure observed in the reaction sup 3 sup 0 Si (p, gamma) sup 3 sup 1 P in the energy region E sub p = 1.4 - 2.7 MeV of accelerated protons is studied. The M1 resonance built on the ground state of sup 3 sup 1 P is identified. The position of the M1 resonance is explained taking into account pairing forces.

Decay properties of rare earth nuclei at high excitation and low spin

International Nuclear Information System (INIS)

Atac, A.

1989-01-01

The purpose of this study was to examine the decay pattern of highly excited rare earth nuclei for which the decay process is expected to be governed by statistical laws. The aim was to investigate how good the statistical model describes the nuclear system and to search for possible deviation from it. It is shown that the gamma decay spectra following both the ( 3 He,α) pick-up reactions and the inelastic ( 3 He, 3 He') reactions reveal similar type of bumps. This leads to the conclusion that the bump structures are not a result of a particular reaction mechanism, but that they have a more general origin. The study is mainly devoted to an examination of the nature of the bumps. 22 refs

BetaBit: A fast generator of autocorrelated binary processes for geophysical research

Science.gov (United States)

Serinaldi, Francesco; Lombardo, Federico

2017-05-01

We introduce a fast and efficient non-iterative algorithm, called BetaBit, to simulate autocorrelated binary processes describing the occurrence of natural hazards, system failures, and other physical and geophysical phenomena characterized by persistence, temporal clustering, and low rate of occurrence. BetaBit overcomes the simulation constraints posed by the discrete nature of the marginal distributions of binary processes by using the link existing between the correlation coefficients of this process and those of the standard Gaussian processes. The performance of BetaBit is tested on binary signals with power-law and exponentially decaying autocorrelation functions (ACFs) corresponding to Hurst-Kolmogorov and Markov processes, respectively. An application to real-world sequences describing rainfall intermittency and the occurrence of strong positive phases of the North Atlantic Oscillation (NAO) index shows that BetaBit can also simulate surrogate data preserving the empirical ACF as well as signals with autoregressive moving average (ARMA) dependence structures. Extensions to cyclo-stationary processes accounting for seasonal fluctuations are also discussed.

Modelling Chemical Reasoning to Predict and Invent Reactions.

Science.gov (United States)

Segler, Marwin H S; Waller, Mark P

2017-05-02

The ability to reason beyond established knowledge allows organic chemists to solve synthetic problems and invent novel transformations. Herein, we propose a model that mimics chemical reasoning, and formalises reaction prediction as finding missing links in a knowledge graph. We have constructed a knowledge graph containing 14.4 million molecules and 8.2 million binary reactions, which represents the bulk of all chemical reactions ever published in the scientific literature. Our model outperforms a rule-based expert system in the reaction prediction task for 180 000 randomly selected binary reactions. The data-driven model generalises even beyond known reaction types, and is thus capable of effectively (re-)discovering novel transformations (even including transition metal-catalysed reactions). Our model enables computers to infer hypotheses about reactivity and reactions by only considering the intrinsic local structure of the graph and because each single reaction prediction is typically achieved in a sub-second time frame, the model can be used as a high-throughput generator of reaction hypotheses for reaction discovery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic field decay in black widow pulsars

Science.gov (United States)

Mendes, Camile; de Avellar, Marcio G. B.; Horvath, J. E.; Souza, Rodrigo A. de; Benvenuto, O. G.; De Vito, M. A.

2018-04-01

We study in this work the evolution of the magnetic field in `redback-black widow' pulsars. Evolutionary calculations of these `spider' systems suggest that first the accretion operates in the redback stage, and later the companion star ablates matter due to winds from the recycled pulsar. It is generally believed that mass accretion by the pulsar results in a rapid decay of the magnetic field when compared to the rate of an isolated neutron star. We study the evolution of the magnetic field in black widow pulsars by solving numerically the induction equation using the modified Crank-Nicolson method with intermittent episodes of mass accretion on to the neutron star. Our results show that the magnetic field does not fall below a minimum value (`bottom field') in spite of the long evolution time of the black widow systems, extending the previous conclusions for much younger low-mass X-ray binary systems. We find that in this scenario, the magnetic field decay is dominated by the accretion rate, and that the existence of a bottom field is likely related to the fact that the surface temperature of the pulsar does not decay as predicted by the current cooling models. We also observe that the impurity of the pulsar crust is not a dominant factor in the decay of magnetic field for the long evolution time of black widow systems.

The influence of massive black hole binaries on the morphology of merger remnants

Science.gov (United States)

Bortolas, E.; Gualandris, A.; Dotti, M.; Read, J. I.

2018-06-01

Massive black hole (MBH) binaries, formed as a result of galaxy mergers, are expected to harden by dynamical friction and three-body stellar scatterings, until emission of gravitational waves (GWs) leads to their final coalescence. According to recent simulations, MBH binaries can efficiently harden via stellar encounters only when the host geometry is triaxial, even if only modestly, as angular momentum diffusion allows an efficient repopulation of the binary loss cone. In this paper, we carry out a suite of N-body simulations of equal-mass galaxy collisions, varying the initial orbits and density profiles for the merging galaxies and running simulations both with and without central MBHs. We find that the presence of an MBH binary in the remnant makes the system nearly oblate, aligned with the galaxy merger plane, within a radius enclosing 100 MBH masses. We never find binary hosts to be prolate on any scale. The decaying MBHs slightly enhance the tangential anisotropy in the centre of the remnant due to angular momentum injection and the slingshot ejection of stars on nearly radial orbits. This latter effect results in about 1 per cent of the remnant stars being expelled from the galactic nucleus. Finally, we do not find any strong connection between the remnant morphology and the binary hardening rate, which depends only on the inner density slope of the remnant galaxy. Our results suggest that MBH binaries are able to coalesce within a few Gyr, even if the binary is found to partially erase the merger-induced triaxiality from the remnant.

Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries

International Nuclear Information System (INIS)

Hermes, J. J.; Brown, Warren R.; Kilic, Mukremin; Gianninas, A.; Chote, Paul; Sullivan, D. J.; Winget, D. E.; Bell, Keaton J.; Falcon, R. E.; Winget, K. I.; Harrold, Samuel T.; Montgomery, M. H.; Mason, Paul A.

2014-01-01

We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the binaries contain low-mass white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely low-mass (≤0.30 M ☉ ) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.

Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries

Energy Technology Data Exchange (ETDEWEB)

Hermes, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Brown, Warren R. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kilic, Mukremin; Gianninas, A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States); Chote, Paul; Sullivan, D. J. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Winget, D. E.; Bell, Keaton J.; Falcon, R. E.; Winget, K. I.; Harrold, Samuel T.; Montgomery, M. H. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Mason, Paul A., E-mail: j.j.hermes@warwick.ac.uk [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States)

2014-09-01

We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the binaries contain low-mass white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely low-mass (≤0.30 M {sub ☉}) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.

Laser photolysis study of anthraquinone in binary mixtures ofionic liquid [bmim][PF6] and organic solvent

Directory of Open Access Journals (Sweden)

Side Yao

2006-12-01

Full Text Available Photochemical properties of the ionic liquid (RTIL 1-butyl-3-methylimidazoliumhexafluorophosphate [bmim][PF6] and its binary mixed solutions with organic solvent(DMF and MeCN were investigated by laser photolysis at an excitation wavelength of 355nm, using anthraquinone (AQ as a probe molecule. It was indicated that the triplet excitedstate of AQ (3AQ* can abstract hydrogen from [bmim][PF6]. Moreover, along with thechange of the ratio of RTIL and organic solvent, the reaction rate constant changes regularly.Critical points were observed at volume fraction VRTIL = 0.2 for RTIL/MeCN and VRTIL =0.05 for RTIL/DMF. For both systems, before the critical point, the rate constant increasesrapidly with increasing VRTIL; however, it decreases obviously with VRTIL after the criticalpoint. We conclude that the concentration dependence is dominant at lower VRTIL, while theviscosity and phase transformation are dominant at higher VRTIL for the effect of ionic liquidon the decay of rate constant.

One-nucleon pickup reactions and compound-nuclear decays

Science.gov (United States)

Escher, J. E.; Burke, J. T.; Casperson, R. J.; Hughes, R. O.; Scielzo, N. D.

2018-05-01

One-nucleon transfer reactions, long used as a tool to study the structure of nuclei, are potentially valuable for determining reaction cross sections indirectly. This is significant, as many reactions of interest to astrophysics and other applications involve short-lived isotopes and cannot be measured directly. We describe a procedure for obtaining constraints for calculations of neutron capture cross sections using observables from experiments with transfer reactions. As a first step toward demonstrating the method, we outline the theory developments used to properly describe the production of the compound nucleus 88Y* via the one-nucleon pickup reaction 89Y(p,d)88Y* and test the description with data from a recent experiment. We indicate how this development can be used to extract the unknown 87Y(n,γ) cross section from 89Y(p,dγ) data. The example illustrates a more generally applicable method for determining unknown cross sections via a combination of theory and transfer (or inelastic scattering) experiments.

Analysis of the reaction γp → K{sup 0}Σ{sup +} in the neutral decay channel at the BGO-OD experiment using kinematic fitting

Energy Technology Data Exchange (ETDEWEB)

Alef, Stefan [Physikalisches Institut, Universitaet Bonn (Germany); Collaboration: BGO-OD-Collaboration

2016-07-01

The BGO-OD experiment at the ELSA facility in Bonn is built to investigate nucleon excitations via meson photoproduction. One research objective is associated strangeness production, which includes the reaction channel γp → K{sup 0}Σ{sup +}. Results of the analysis for the neutral decay channel K{sup 0}Σ{sup +} → π{sup 0}π{sup 0}π{sup 0}p will be presented. Due to the small production cross section and branching ratio kinematic fitting is used to discriminate the reaction against background.

A novel and facile decay path of Criegee intermediates by intramolecular insertion reactions via roaming transition states

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Trong-Nghia [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Physical Chemistry, Hanoi University of Science and Technology, Hanoi (Viet Nam); Putikam, Raghunath; Lin, M. C., E-mail: chemmcl@emory.edu [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

2015-03-28

We have discovered a new and highly competitive product channel in the unimolecular decay process for small Criegee intermediates, CH{sub 2}OO and anti/syn-CH{sub 3}C(H)OO, occurring by intramolecular insertion reactions via a roaming-like transition state (TS) based on quantum-chemical calculations. Our results show that in the decomposition of CH{sub 2}OO and anti-CH{sub 3}C(H)OO, the predominant paths directly produce cis-HC(O)OH and syn-CH{sub 3}C(O)OH acids with >110 kcal/mol exothermicities via loose roaming-like insertion TSs involving the terminal O atom and the neighboring C–H bonds. For syn-CH{sub 3}C(H)OO, the major decomposition channel occurs by abstraction of a H atom from the CH{sub 3} group by the terminal O atom producing CH{sub 2}C(H)O–OH. At 298 K, the intramolecular insertion process in CH{sub 2}OO was found to be 600 times faster than the commonly assumed ring-closing reaction.

Update and evaluation of decay data for spent nuclear fuel analyses

Science.gov (United States)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Update and evaluation of decay data for spent nuclear fuel analyses

Directory of Open Access Journals (Sweden)

Simeonov Teodosi

2017-01-01

Full Text Available Studsvik’s approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL and processed (ESTAR sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources. Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Beta decay of /sup 39/Cl

International Nuclear Information System (INIS)

Wang, G.; Warburton, E.K.; Alburger, D.E.

1987-01-01

The β decay of /sup 39/Cl, produced in the /sup 37/Cl(t,p)/sup 39/Cl reaction at E/sub t/ = 3.1 MeV, has been investigated with a Ge-NaI(Tl) Compton-suppression γ-ray spectrometer. Nineteen γ-ray transitions were observed, including 10 previously known. Precision energy measurements were carried out on six of the strongest lines. In the proposed decay scheme a weak new β-ray branch is established to the 2950-keV level of /sup 39/Ar, and the populations of /sup 39/Ar levels at 2093 and 2433 keV are accounted for by γ-ray decays from higher excited states. Spin-parity assignments are given

Learning to assign binary weights to binary descriptor

Science.gov (United States)

Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

2016-10-01

Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

Decay properties of high-lying single-particles modes

Energy Technology Data Exchange (ETDEWEB)

Beaumel, D. [Institut de Physique Nucleaire, 91 - Orsay (France); Fortier, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Gales, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Guillot, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Langevin-Joliot, H. [Institut de Physique Nucleaire, 91 - Orsay (France); Laurent, H. [Institut de Physique Nucleaire, 91 -Orsay (France); Maison, J.M. [Institut de Physique Nucleaire, 91 - Orsay (France); Vernotte, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Bordewijck, J. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Brandenburg, S. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Krasznahorkay, A. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Crawley, G.M. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Massolo, C.P. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Renteria, M. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Khendriche, A. [University of Tizi-Ouzou, Tizi-Ouzou (Algeria)

1996-03-18

The neutron decay of high-lying single-particle states in {sup 64}Ni, {sup 90}Zr, {sup 120}Sn and {sup 208}Pb excited by means of the ({alpha},{sup 3}He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in {sup 91}Zr, and between 8 and 12 MeV excitation energy in {sup 209}Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations. (orig.).

NuSTAR and XMM-Newton Observations of the 2015 Outburst Decay of GX 339-4

Energy Technology Data Exchange (ETDEWEB)

Stiele, H.; Kong, A. K. H., E-mail: hstiele@mx.nthu.edu.tw [National Tsing Hua University, Department of Physics and Institute of Astronomy, No. 101 Sect. 2 Kuang-Fu Road, 30013, Hsinchu, Taiwan (China)

2017-07-20

The extent of the accretion disk in the low/hard state of stellar mass black hole X-ray binaries remains an open question. There is some evidence suggesting that the inner accretion disk is truncated and replaced by a hot flow, while the detection of relativistic broadened iron emission lines seems to require an accretion disk extending fully to the innermost stable circular orbit. We present comprehensive spectral and timing analyses of six Nuclear Spectroscopic Telescope Array and XMM-Newton observations of GX 339–4 taken during outburst decay in the autumn of 2015. Using a spectral model consisting of a thermal accretion disk, Comptonized emission, and a relativistic reflection component, we obtain a decreasing photon index, consistent with an X-ray binary during outburst decay. Although we observe a discrepancy in the inner radius of the accretion disk and that of the reflector, which can be attributed to the different underlying assumptions in each model, both model components indicate a truncated accretion disk that resiles with decreasing luminosity. The evolution of the characteristic frequency in Fourier power spectra and their missing energy dependence support the interpretation of a truncated and evolving disk in the hard state. The XMM-Newton data set allowed us to study, for the first time, the evolution of the covariance spectra and ratio during outburst decay. The covariance ratio increases and steeps during outburst decay, consistent with increased disk instabilities.

Binary Linear-Time Erasure Decoding for Non-Binary LDPC codes

OpenAIRE

Savin, Valentin

2009-01-01

In this paper, we first introduce the extended binary representation of non-binary codes, which corresponds to a covering graph of the bipartite graph associated with the non-binary code. Then we show that non-binary codewords correspond to binary codewords of the extended representation that further satisfy some simplex-constraint: that is, bits lying over the same symbol-node of the non-binary graph must form a codeword of a simplex code. Applied to the binary erasure channel, this descript...

Random numbers spring from alpha decay

International Nuclear Information System (INIS)

Frigerio, N.A.; Sanathanan, L.P.; Morley, M.; Clark, N.A.; Tyler, S.A.

1980-05-01

Congruential random number generators, which are widely used in Monte Carlo simulations, are deficient in that the number they generate are concentrated in a relatively small number of hyperplanes. While this deficiency may not be a limitation in small Monte Carlo studies involving a few variables, it introduces a significant bias in large simulations requiring high resolution. This bias was recognized and assessed during preparations for an accident analysis study of nuclear power plants. This report describes a random number device based on the radioactive decay of alpha particles from a 235 U source in a high-resolution gas proportional counter. The signals were fed to a 4096-channel analyzer and for each channel the frequency of signals registered in a 20,000-microsecond interval was recorded. The parity bits of these frequency counts (0 for an even count and 1 for an odd count) were then assembled in sequence to form 31-bit binary random numbers and transcribed to a magnetic tape. This cycle was repeated as many times as were necessary to create 3 million random numbers. The frequency distribution of counts from the present device conforms to the Brockwell-Moyal distribution, which takes into account the dead time of the counter (both the dead time and decay constant of the underlying Poisson process were estimated). Analysis of the count data and tests of randomness on a sample set of the 31-bit binary numbers indicate that this random number device is a highly reliable source of truly random numbers. Its use is, therefore, recommended in Monte Carlo simulations for which the congruential pseudorandom number generators are found to be inadequate. 6 figures, 5 tables

Why search for double beta decay?

International Nuclear Information System (INIS)

Kayser, B.

1988-01-01

Searching for neutrinoless double beta decay is the only known practical method for trying to determine whether neutrinos are their own antiparticles. The theoretical motivation for supposing that they may indeed be their own antiparticles is described. The reason that it is so difficult to ascertain experimentally whether they are or are not is explained, as is the special sensitivity of neutrinoless double beta decay. The potential implications of the observation of this reaction for neutrino mass and for the physics of neutrinos is discussed

Binary effectivity rules

DEFF Research Database (Denmark)

Keiding, Hans; Peleg, Bezalel

2006-01-01

is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...

The 12C + 12C: 1. Decay into high spin states of 23Mg, and 23Na. 2. Hauser-Feshbach analysis of the reaction mechanism

International Nuclear Information System (INIS)

Denhoefer, G.

1980-01-01

In this thesis different aspects of the reaction 12 C + 12 C were studied. The first part deals with high spin states in the mirror nucki 23 Na and 23 Mg experially with the states resonantly populated at Esub(cm) = 19.3 MeV. For the state at 9.80 MeV in 23 Na with (p,γ) angular correlation measurements a spin of 17/2 + and by Doppler form analysis a lifetime of (21 +- 9)fs was found. The probably analogous state at 9.61 MeV in 23 Mg decays both under p-emission to 22 Na and under γ-emission. Because of the p-decay probabilities to 3 + and 4 + of 22 Na, which were observed in (p,n) coincidence measurements, it has also the spin 17/2 + . In the second part of this thesis it was studied whether the reaction 12 C + 12 C at incident energies between 26 MeV and 42 MeV can be described using the statistical model. (orig./HSI) [de

Decay of the giant quadrupoles resonance and higher excitation states in 40Ca

International Nuclear Information System (INIS)

Alamanos, N.; Fernandez, B.; Gillibert, A.

1991-01-01

Light charged particles have been measured in coincidence with inelastically scattered fragments from the 40 Ca + 40 Ca reaction at 50 MeV/N. Such a measurement allows to unravel the different reaction mechanisms contributing to the inelastic spectrum: pick-up break-up reactions, knock out and inelastic excitations. The giant quadrupole resonance in 40 Ca is shown to present a 30% non statistical decay branch. A prominent structure at 34 MeV is attributed to target excitation, the decay of this structure is studied

Decay properties of high-lying single-particles modes

NARCIS (Netherlands)

Beaumel, D; Fortier, S; Gales, S; Guillot, J; LangevinJoliot, H; Laurent, H; Maison, JM; Vernotte, J; Bordewijck, J; Brandenburg, S; Krasznahorkay, A; Crawley, GM; Massolo, CP; Renteria, M; Khendriche, A

1996-01-01

The neutron decay of high-lying single-particle states in Ni-64, Zr-90, Sn-120 and (208)pb excited by means of the (alpha,He-3) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular

Thermonuclear reaction rates. III

International Nuclear Information System (INIS)

Harris, M.J.; Fowler, W.A.; Caughlan, G.R.; Zimmerman, B.A.

1983-01-01

Stellar thermonuclear reaction rates are revised and updated, adding a number of new important reaction rates. Several reactions with large negative Q-values are included, and examples of them are discussed. The importance of the decay rates for Mg-26(p,n) exp 26 Al and Al-26(n,p) exp 26 Mg for stellar studies is emphasized. 19 references

Observation of Δ+→pπ0 decay in nuclear matter

International Nuclear Information System (INIS)

Matulewicz, T.; Aphecetche, L.; Charbonnier, Y.; Delagrange, H.; Martinez, G.; Schutz, Y.; Marques, F.M.

1997-01-01

The Δ baryonic resonances production and decay in nuclear matter have been studied. The heavy ion reaction of 180 A MeV Ar beam on Ca target was used to create the Δ resonances (at SIS GSI Darmstadt). The decay of Δ was measured by means of neutral pion π 0 decay product, two gamma quanta, registration. The Δ resonance invariant mass distribution has been determined

First results of 35 MeV/u Kr + Au experiment at GANIL (Caen)

International Nuclear Information System (INIS)

Adloff, J.C.; Boishu, B.; Dalili, D.

1984-01-01

Preliminary results of a study of the Kr + Au breakup reaction at 35 MeV/u performed at GANIL are presented. Atomic number versus velocity distributions are presented for reaction fragments under various conditions. The results are explained by a kinematic model involving fast binary reactions followed by sequential decays by fission

Formation and decay of hot nuclei

International Nuclear Information System (INIS)

Tamain, B.

1992-09-01

The mechanisms involved in hot nuclei formation and decay and their eventual connexion with fundamental properties of nuclear matter are discussed, i.e. its equation of state is considered. After a brief review of the reactions in which hot nuclei can be formed, the variables which are used to describe them, the corresponding theoretical descriptions and their limits when extreme states are reached are discussed. Experimental evidences for hot nuclei formation are presented, with the corresponding decay properties used as signatures. (R.P.) 64 refs.; 25 figs.; 2 tabs

How to calculate α-decay rates in the future?

International Nuclear Information System (INIS)

Carlsson, B. Gillis; Ward, Daniel E.; Åberg, Sven

2016-01-01

New elements discovered during past decades have been created in fusion reactions where a lighter nucleus is collided with a heavier one. The new elements created often decay by emitting α particles. From the half-lives of the decays and the energies of the emitted particles one may extract some properties of the new elements. In this talk the recent work performed by the Lund group to model α decay starting from nuclear density-functional theory is reviewed and a possible extension is mentioned.

Enzymatic synthesis of 6-O-glucosyl-poly(3-hydroxyalkanoate) in organic solvents and their binary mixture.

Science.gov (United States)

Gumel, A M; Annuar, M S M; Heidelberg, T

2013-04-01

The effects of organic solvents and their binary mixture in the glucose functionalization of bacterial poly-3-hydroxyalkanoates catalyzed by Lecitase™ Ultra were studied. Equal volume binary mixture of DMSO and chloroform with moderate polarity was more effective for the enzyme catalyzed synthesis of the carbohydrate polymer at ≈38.2 (±0.8)% reactant conversion as compared to the mono-phasic and other binary solvents studied. The apparent reaction rate constant as a function of medium water activity (aw) was observed to increase with increasing solvent polarity, with optimum aw of 0.2, 0.4 and 0.7 (±0.1) observed in hydrophilic DMSO, binary mixture DMSO:isooctane and hydrophobic isooctane, respectively. Molecular sieve loading between 13 to 15gL(-1) (±0.2) and reaction temperature between 40 to 50°C were found optimal. Functionalized PHA polymer showed potential characteristics and biodegradability. Copyright © 2012 Elsevier B.V. All rights reserved.

The gravitational-wave memory from eccentric binaries

International Nuclear Information System (INIS)

Favata, Marc

2011-01-01

The nonlinear gravitational-wave memory causes a time-varying but nonoscillatory correction to the gravitational-wave polarizations. It arises from gravitational-waves that are sourced by gravitational-waves. Previous considerations of the nonlinear memory effect have focused on quasicircular binaries. Here I consider the nonlinear memory from Newtonian orbits with arbitrary eccentricity. Expressions for the waveform polarizations and spin-weighted spherical-harmonic modes are derived for elliptic, hyperbolic, parabolic, and radial orbits. In the hyperbolic, parabolic, and radial cases the nonlinear memory provides a 2.5 post-Newtonian (PN) correction to the leading-order waveforms. This is in contrast to the elliptical and quasicircular cases, where the nonlinear memory corrects the waveform at leading (0PN) order. This difference in PN order arises from the fact that the memory builds up over a short ''scattering'' time scale in the hyperbolic case, as opposed to a much longer radiation-reaction time scale in the elliptical case. The nonlinear memory corrections presented here complete our knowledge of the leading-order (Peters-Mathews) waveforms for elliptical orbits. These calculations are also relevant for binaries with quasicircular orbits in the present epoch which had, in the past, large eccentricities. Because the nonlinear memory depends sensitively on the past evolution of a binary, I discuss the effect of this early-time eccentricity on the value of the late-time memory in nearly circularized binaries. I also discuss the observability of large ''memory jumps'' in a binary's past that could arise from its formation in a capture process. Lastly, I provide estimates of the signal-to-noise ratio of the linear and nonlinear memories from hyperbolic and parabolic binaries.

PHOTOINITIATED POLYMERIZATION BY ARYLIODONIUM SALT/BENZOPHENONE / TERTIARY AMINE BINARY PHOTOSENSITIZATION SYSTEM

Institute of Scientific and Technical Information of China (English)

HE Junhui; WANG Erjian

1990-01-01

A novel binary photosensitization system composed of benzophenone (BP) /diphenyliodonium chloride ( DPIOC )/triethylamine (TEA), exhibiting a good photoresponse at near UV and visible light regions, was used as the initiator for photopolymerization of MMA. The radical photogeneration in the binary system consists mainly of two parallel reactions, i. e., BP/TEA photohydrogen-abstraction and DPIOC/TEA complex photodecomposition, but the latter is more active than the former. The results of comparative study indicate that the rate of polymerization induced by the binary system (BDT) is remarkably higher than those by the corresponding single systems The polymerization rates are proportional to[BP] 0. 16, [ DPIOC] 0.32, [ TEA ] 0.45 and [MMA ] . The mechanism is also discussed.

The ρ and ω mesons production in the γp reaction

International Nuclear Information System (INIS)

Das, Swapan

2016-01-01

The ρ - ω interference has been well studied in the pion decay channel. The information about this interference in the e"+ e"- decay exist only for the γ-C reaction due to Biggs et al., and for the γ-Be reaction due to Alvenslaben et al.. The interference phases derived in the pionic and electromagnetic decay channels are different and this discrepancy is never understood

New model of chlorine-wall reaction for simulating chlorine concentration in drinking water distribution systems.

Science.gov (United States)

Fisher, Ian; Kastl, George; Sathasivan, Arumugam

2017-11-15

Accurate modelling of chlorine concentrations throughout a drinking water system needs sound mathematical descriptions of decay mechanisms in bulk water and at pipe walls. Wall-reaction rates along pipelines in three different systems were calculated from differences between field chlorine profiles and accurately modelled bulk decay. Lined pipes with sufficiently large diameters (>500 mm) and higher chlorine concentrations (>0.5 mg/L) had negligible wall-decay rates, compared with bulk-decay rates. Further downstream, wall-reaction rate consistently increased (peaking around 0.15 mg/dm 2 /h) as chlorine concentration decreased, until mass-transport to the wall was controlling wall reaction. These results contradict wall-reaction models, including those incorporated in the EPANET software, which assume wall decay is of either zero-order (constant decay rate) or first-order (wall-decay rate reduces with chlorine concentration). Instead, results are consistent with facilitation of the wall reaction by biofilm activity, rather than surficial chemical reactions. A new model of wall reaction combines the effect of biofilm activity moderated by chlorine concentration and mass-transport limitation. This wall reaction model, with an accurate bulk chlorine decay model, is essential for sufficiently accurate prediction of chlorine residuals towards the end of distribution systems and therefore control of microbial contamination. Implementing this model in EPANET-MSX (or similar) software enables the accurate chlorine modelling required for improving disinfection strategies in drinking water networks. New insight into the effect of chlorine on biofilm can also assist in controlling biofilm to maintain chlorine residuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Constraining f(R) gravity in solar system, cosmology and binary pulsar systems

Science.gov (United States)

Liu, Tan; Zhang, Xing; Zhao, Wen

2018-02-01

The f (R) gravity can be cast into the form of a scalar-tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general f (R) gravity, using a scalar-tensor representation with the chameleon mechanism, we calculate the parametrized post-Newtonian parameters γ and β, the effective gravitational constant Geff, and the effective cosmological constant Λeff. In addition, for the general f (R) gravity, we also calculate the rate of orbital period decay of the binary system due to gravitational radiation. Then we apply these results to specific f (R) models (Hu-Sawicki model, Tsujikawa model and Starobinsky model) and derive the constraints on the model parameters by combining the observations in solar system, cosmological scales and the binary systems.

Table of nuclear reactions and subsequent radioactive dacays induced by 14-MeV neutrons

International Nuclear Information System (INIS)

Tsukada, Kineo

1977-09-01

Compilation of the data on nuclear reactions and subsequent radioactive decays induced by 14-MeV neutrons is presented in tabular form for most of the isotopes available in nature and for some of the artificially-produced isotopes, including the following items: Nuclide (isotopic abundance), type of nuclear reaction, reaction Q-value, reaction product, type of decay, decay Q-value, half-life of reaction product, decay product, maximum reaction cross section, neutron energy for maximum cross section, reaction cross section for 14 MeV neutrons, saturated radioactivity induced by irradiation of a neutron flux of 1 n/cm 2 sec for a mol of atoms, and reference for the cross section. The mass number dependence of (n, γ), (n, 2n), (n, p), (n, d), (n, t), (n, 3 He) and (n, α) reaction cross sections for 14-MeV neutrons is given in figures to show general trends of the cross sections

Methods for the analysis of complex fluorescence decays: sum of Becquerel functions versus sum of exponentials

International Nuclear Information System (INIS)

Menezes, Filipe; Fedorov, Alexander; Baleizão, Carlos; Berberan-Santos, Mário N; Valeur, Bernard

2013-01-01

Ensemble fluorescence decays are usually analyzed with a sum of exponentials. However, broad continuous distributions of lifetimes, either unimodal or multimodal, occur in many situations. A simple and flexible fitting function for these cases that encompasses the exponential is the Becquerel function. In this work, the applicability of the Becquerel function for the analysis of complex decays of several kinds is tested. For this purpose, decays of mixtures of four different fluorescence standards (binary, ternary and quaternary mixtures) are measured and analyzed. For binary and ternary mixtures, the expected sum of narrow distributions is well recovered from the Becquerel functions analysis, if the correct number of components is used. For ternary mixtures, however, satisfactory fits are also obtained with a number of Becquerel functions smaller than the true number of fluorophores in the mixture, at the expense of broadening the lifetime distributions of the fictitious components. The quaternary mixture studied is well fitted with both a sum of three exponentials and a sum of two Becquerel functions, showing the inevitable loss of information when the number of components is large. Decays of a fluorophore in a heterogeneous environment, known to be represented by unimodal and broad continuous distributions (as previously obtained by the maximum entropy method), are also measured and analyzed. It is concluded that these distributions can be recovered by the Becquerel function method with an accuracy similar to that of the much more complex maximum entropy method. It is also shown that the polar (or phasor) plot is not always helpful for ascertaining the degree (and kind) of complexity of a fluorescence decay. (paper)

Alpha decay of 114Ba

International Nuclear Information System (INIS)

Mazzocchi, C.; Janas, Z.; Batist, L.; Belleguic, V.; Doering, J.; Kapica, M.; Kirchner, R.; Roeckl, E.; Gierlik, M.; Zylicz, J.; Mahmud, H.; Schmidt, K.; Woods, P.J.

2003-01-01

The neutron-deficient isotope 114 Ba was produced in a fusion evaporation reaction at the GSI On-Line Mass Separator. We measured the α-particle energy of 114 Ba, the half-life of its daughter nucleus 110 Xe, and the α-decay branching ratios for 114 Ba, 110 Xe and 106 Te. (orig.)

Beta-decay studies near 100Sn

International Nuclear Information System (INIS)

Rykaczewski, Krzysztof Piotr; Karny, M.; Batist, L.; Banu, A.; Becker, F.; Blazhev, A.; Burkard, K.; Bruchle, W.; Doring, J.; Faestermann, T.; Gorska, M.; Grawe, H.; Janas, Z.; Jungclaus, A.; Kavatsyuk, M.; Kavatsyuk, O.; Kirchner, R.; La Commara, M.; Mandal, S.; Mazzocchi, C.; Miernik, K.; Mukha, I.; Muralithar, S.; Plettner, C.; Plochocki, A.; Roeckl, E.; Romoli, M.; Schadel, M.; Schmidt, K.; Schwengner, R.; Zylicz, J.

2005-01-01

The β-decay of 102 Sn was studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). A decay scheme has been constructed based on the γ-γ coincidence data. The total experimental Gamow-Teller strength B GT exp of 102 Sn was deduced from the TAS data to be 4.2(9). A search for β-delayed γ-rays of 100 Sn decay remained unsuccessful. However, a Gamow-Teller hindrance factor h = 2.2(3), and a cross-section of about 3nb for the production of 100 Sn in fusion-evaporation reaction between 58 Ni beam and 50 Cr target have been estimated from the data on heavier tin isotopes. The estimated hindrance factor is similar to the values derived for lower shell nuclei

Dynamics of traveling reaction pulses

International Nuclear Information System (INIS)

Dovzhenko, A. Yu.; Rumanov, E. N.

2007-01-01

The growth of activator losses is accompanied by the decay of a traveling reaction pulse. In a ring reactor, this propagation threshold is present simultaneously with a threshold related to the ring diameter. The results of numerical experiments with pulses of an exothermal reaction reveal the transition from pulse propagation to a homogeneous hot regime, established regimes with periodic variations of the pulse velocity, and oscillatory decay of the pulse. When the medium becomes 'bistable' as a result of the variation in parameters, this factor does not prevent the propagation of pulses, but leads to changes in the pulse structure

The Synthesis and Decay Properties of the Heaviest Elements

CERN Document Server

Oganessian, Yu T

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the "islands of stability" of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus ^{208}Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with ^{48}Ca. In these reactions the decay chains of heavy atoms consisting of sequential alpha-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first exper...

Nuclear-decay studies of neutron-rich rare-earth nuclides

International Nuclear Information System (INIS)

Chasteler, R.M.

1990-01-01

Neutron-rich rare-earth nuclei were produced in multinucleon transfer reactions of 170 Er and 176 Yb projectiles on nat W targets at the Lawrence Berkeley Laboratory SuperHILAC and their radioactive decays properties studied at the on-line mass separation facility OASIS. Two unknown isotopes, 169 Dy (t 1/2 = 39 ± 8 s) and 174 Er(t 1/2 = 3.3 ± 0.2 m) were discovered and their decay characteristics determined. The decay schemes for two previously identified isotopes, 168 Dy (t 1/2 = 8.8 ± 0.3 m) and 171 Ho (t 1/2 = 55 ± 3 s), were characterized. Evidence for a new isomer of 3.0 m 168 Ho g , 168 Ho m (t 1/2 = 132 ± 4 s) which decays by isomeric transition (IT) is presented. Beta particle endpoint energies were determined for the decay of 168 Ho g , 169 Dy, 171 Ho, and 174 Er, the resulting Qβ-values are: 2.93 ± 0.03, 3.2 ± 0.3, 3.2 ± 0.6, and 1.8 ± 0.2 MeV, respectively. These values were compared with values calculated using recent atomic mass formulae. Comparisons of various target/ion source geometries used in the OASIS mass separator facility for these multinucleon transfer reactions were performed. 73 refs., 40 figs., 11 tabs

Improved Limit on Direct α Decay of the Hoyle State

DEFF Research Database (Denmark)

Kirsebom, Oliver Sølund; Alcorta, M.; Borge, M.J.G.

2012-01-01

The current evaluation of the triple-α reaction rate assumes that the α decay of the 7.65 MeV, 0+ state in 12C, commonly known as the Hoyle state, proceeds sequentially via the ground state of 8Be. This assumption is challenged by the recent identification of two direct α-decay branches with a co...

Organometallic Routes into the Nanorealms of Binary Fe-Si Phases

Directory of Open Access Journals (Sweden)

Teddy M. Keller

2010-02-01

Full Text Available The Fe-Si binary system provides several iron silicides that have varied and exceptional material properties with applications in the electronic industry. The well known Fe-Si binary silicides are Fe3Si, Fe5Si3, FeSi, a-FeSi2 and b-FeSi2. While the iron-rich silicides Fe3Si and Fe5Si3 are known to be room temperature ferromagnets, the stoichiometric FeSi is the only known transition metal Kondo insulator. Furthermore, Fe5Si3 has also been demonstrated to exhibit giant magnetoresistance (GMR. The silicon-rich b-FeSi2 is a direct band gap material usable in light emitting diode (LED applications. Typically, these silicides are synthesized by traditional solid-state reactions or by ion beam-induced mixing (IBM of alternating metal and silicon layers. Alternatively, the utilization of organometallic compounds with reactive transition metal (Fe-carbon bonds has opened various routes for the preparation of these silicides and the silicon-stabilized bcc- and fcc-Fe phases contained in the Fe-Si binary phase diagram. The unique interfacial interactions of carbon with the Fe and Si components have resulted in the preferential formation of nanoscale versions of these materials. This review will discuss such reactions.

Virtual reality: electromagnetic decays and new hadrons

International Nuclear Information System (INIS)

Landsberg, L.G.

1998-01-01

The electromagnetic Coulomb processes and their application to study of radiative decays of hadrons and to the search for some exotic states are discussed. The Coulomb processes h + (Z, A) → (Z, A) involving collisions with virtual photons are photoproduction reactions on primary hadrons h. With pion, kaon or hyperon beams it is possible to study photoproduction on unstable targets (π, Κ, Υ). The results of several experiments for direct study of rare radiation decays of mesons are presented. The main features of the Coulomb production and coherent background reactions governed by strong interactions are considered. The main results of the Primakoff production study are summarized with some recent data in the SELEX experiment at E L = 600 eV obtained by means of Fermilab Tevatron. The SPHINX experiment allows to obtain new information on exotic baryons and other states [ru

Anomalous decay and scattering processes of the meson

Science.gov (United States)

Kubis, Bastian; Plenter, Judith

2015-06-01

We amend a recent dispersive analysis of the anomalous decay process by the effects of the tensor meson, the lowest-lying resonance that can contribute in the system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous decay. There are nonnegligible consequences for the transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward-backward asymmetry, for the crossed process , which could be measured in Primakoff reactions in the future.

Decay modes of high-lying excitations in nuclei

International Nuclear Information System (INIS)

Gales, S.

1993-01-01

Inelastic, charge-exchange and transfer reactions induced by hadronic probes at intermediate energies have revealed a rich spectrum of new high-lying modes embedded in the nuclear continuum. The investigation of their decay properties is believed to be a severe test of their microscopic structure as predicted by nuclear models. In addition the degree of damping of these simple modes in the nuclear continuum can be obtained by means of the measured branching ratios to the various decay channels as compared to statistical model calculations. As illustrative examples the decay modes of high-spin single-particle states and isovector resonances are discussed. (author) 23 refs.; 14 figs

Decay Spectroscopy for Nuclear Astrophysics: {beta}-delayed Proton Decay

Energy Technology Data Exchange (ETDEWEB)

Trache, L.; Simmons, E.; Spiridon, A.; McCleskey, M.; Roeder, B. T.; Tribble, R. E. [Texas A and M University, College Station, TX 77845 (United States); Saastamoinen, A.; Jokinen, A.; Aysto, J. [University of Jyvaskyla, Jyvaskyla (Finland); Davinson, T.; Woods, P. J. [University of Edinburgh, Edinburgh (United Kingdom); Pollacco, E.; Kebbiri, M. [CEA/IRFU Saclay (France); Pascovici, G. [IKP, Universitaet zu Koeln (Germany)

2011-11-30

Decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. We have developed at TAMU techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of {sup 23}Al, {sup 27}P, {sup 31}Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions {sup 22}Na(p,{gamma}){sup 23}Mg(crucial for the depletion of {sup 22}Na in novae), {sup 26m}Al(p,{gamma}){sup 27}Si and {sup 30}P(p,{gamma}){sup 31}S(bottleneck in novae and XRB burning), respectively. More recently we have radically improved the technique using a gas based detector we call AstroBox.

Isospin influence on the decay modes of the systems produced in the 78,86Kr +40,48Ca reactions at 10 AMeV

Directory of Open Access Journals (Sweden)

Gnoffo B.

2016-01-01

Full Text Available The results of the analysis of the reactions 78,86Kr +40,48 Ca at 10 AMeV are presented. The experiment was performed at the INFN Laboratori Nazionali del Sud (LNS in Catania by using the 4π multidetector CHIMERA, with beams delivered by the Superconductive Cyclotron. The competition among the various disintegration paths and in particular the isospin effects on the decay modes of the produced composite systems are investigated; this provides information about fundamental nuclear quantities such as level density, fission barrier and viscosity. Different isotopic composition and relative richness are observed among the reaction products of the two systems. An odd-even staggering effect is present in the charge distributions, in particular for the light fragments produced by the neutron-poor system. The kinematical characteristics of the IMF seem to indicate a high degree of the relaxation of the formed system. Besides, global features analysis seems to show some differences in the contribution arising from the various reaction mechanisms for the two reactions.

Development of odd-Z-projectile reactions for transactinide element synthesis

International Nuclear Information System (INIS)

Folden III, Charles Marvin

2004-01-01

The development of new odd-Z-projectile reactions leading to the production of transactinide elements is described. The cross section of the even-Z-projectile 208Pb(64Ni, n)271Ds reaction was measured at two new energies using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. In total, seven decay chains attributable to 271Ds were observed. These data, combined with previous results, establish an excitation function for the production of 271Ds. The maximum cross section was 20 +15 -11 pb at a center-of-target energy of 311.5 MeV in the laboratory frame.The data from the 271Ds experiments were used to estimate the optimum beam energy for the new odd-Z-projectile 208Pb(65Cu, n)272-111 reaction using the Fusion by Diffusion theory proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski. A cross section for this reaction was measured for the first time, at a center-of-target energy of 321.1 MeV in the laboratory frame. The excitation energy f or compound nuclei formed at the target center was 13.2 MeV. One decay chain was observed, resulting in a measured cross section of 1.7 +3.9 -1.4 pb. This decay chain is in good agreement with previously published data on the decay of 272-111.The new odd-Z-projectile 208Pb(55Mn, n)262Bh reaction was studied at three different projectile energies, and 33 decay chains of 262Bh were observed. The existence of a previously reported alpha-decaying isomeric state in this nuclide was confirmed. Production of the ground state was preferred at all three beam energies. The maximum cross section was 540 +180 -150 pb at a projectile center-of-target energy of 264.0 MeV. This cross section is much larger than that previously reported for the even-Z-projectile 209Bi(54Cr, n)262Bh reaction, which may be because the 54Cr projectile energies in the latter reaction were too high for optimum production of the 1n product. At the highest projectile energy of 268.0 MeV in the target center, two decay

Study of N-13 decay on time using continuous kinetic function method

International Nuclear Information System (INIS)

Tran Dai Nghiep; Vu Hoang Lam; Nguyen Ngoc Son; Nguyen Duc Thanh

1993-01-01

The decay function from radioisotope 13 N formed in the reaction 14 N(γ,n) 13 N was registered by high resolution gamma spectrometer in multiscanning mode with gamma energy 511 keV. The experimental data was processed by common and kinetic function method. The continuous comparison of the decay function on time permits to determinate possible deviation from purely exponential decay curve. The results were described by several decay theories. The degrees of corresponding between theories and experiment were evaluated by goodness factor. A complex type of decay was considered. (author). 9 refs, 2 tabs, 6 figs

Beta decay of Cu-56

NARCIS (Netherlands)

Borcea, R; Aysto, J; Caurier, E; Dendooven, P; Doring, J; Gierlik, M; Gorska, M; Grawe, H; Hellstrom, M; Janas, Z; Jokinen, A; Karny, M; Kirchner, R; La Commara, M; Langanke, K; Martinez-Pinedo, G; Mayet, P; Nieminen, A; Nowacki, F; Penttila, H; Plochocki, A; Rejmund, M; Roeckl, E; Schlegel, C; Schmidt, K; Schwengner, R; Sawicka, M

2001-01-01

The proton-rich isotope Cu-56 was produced at the GSI On-Line Mass Separator by means of the Si-28(S-32, p3n) fusion-evaporation reaction. Its beta -decay properties were studied by detecting beta -delayed gamma rays and protons. A half-Life of 93 +/- 3 ms was determined for Cu-56. Compared to the

Black hole binary OJ287 as a testing platform for general relativity

International Nuclear Information System (INIS)

Valtonen, M J; Gopakumar, A; Mikkola, S; Wiik, K; Lehto, H J

2014-01-01

The blazar OJ287 is the most promising (and the only) case for an extragalactic binary black hole system inspiralling under the action of gravitational radiation reaction. At present, though it is not possible to directly observe the binary components, it is possible to observe the jet emanating from the primary black hole. We have argued that the orbital motion of the secondary black hole is reflected in the wobble of the jet, and demonstrated that the wobble is orbital position dependent. The erratic wobble of the jet is analyzed by taking into account the binary nature of the system, and we have found that the erratic component of jet wobble is very small

Gravitational waves from spinning eccentric binaries

Science.gov (United States)

Csizmadia, Péter; Debreczeni, Gergely; Rácz, István; Vasúth, Mátyás

2012-12-01

This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations, while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems, it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity, thus confirming a similar result obtained by Brown and Zimmerman (2010 Phys. Rev. D 81 024007). In addition, by investigating the validity of the energy balance relation we show that, contrary to the general expectations, the PN approximation should not be applied once the PN parameter gets beyond the critical value ˜0.08 - 0.1. Finally, by studying the early phase of the gravitational waves emitted by strongly eccentric binary systems—which could be formed e.g. in various many-body interactions in the galactic halo—we have found that they possess very specific characteristics which may be used to identify these type of binary systems. This paper is dedicated to the memory of our colleague and friend Péter Csizmadia a young physicist, computer expert and one of the best Hungarian mountaineers who disappeared in China’s Sichuan near the Ren Zhong Feng peak of the Himalayas on 23 Oct. 2009. We started to develop CBwaves jointly with Péter a couple of months before he left for China.

Decay studies of neutron-deficient lawrencium isotopes

International Nuclear Information System (INIS)

Antalic, S.; Saro, S.; Streicher, B.; Venhart, M.; Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Hofmann, S.; Kuusiniemi, P.; Leino, M.; Nishio, K.; Sulignano, B.

2008-01-01

The radioactive decay of the isotopes 254-256 Lr and their daughter products was investigated by means of α, prompt α-γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction 48 Ca+ 209 Bi. (orig.)

Λ(1520) → Λγ Radiative-Decay Width

International Nuclear Information System (INIS)

Vavilov, D.V.; Antipov, Yu.M.; Artamonov, A.V.; Batarin, V.A.; Victorov, V.A.; Golovkin, S.V.; Gorin, Yu.P.; Eroshin, O.V.; Kozhevnikov, A.P.; Konstantinov, A.S.; Kubarovsky, V.P.; Kurshetsov, V.F.; Landsberg, L.G.; Leontiev, V.M.; Molchanov, V.V.; Mukhin, V.A.; Patalakha, D.I.; Petrenko, S.V.; Petrukhin, A.I.; Kolganov, V.Z.

2005-01-01

The radiative decay Λ(1520) → Λγ was recorded in the exclusive reaction p + N → Λ(1520)K + + N at the SPHINX facility. The branching ratio for this decay and the corresponding partial width were found to be, respectively, Br[Λ(1520) → Λγ] = (1.02 ± 0.21) x 10 -2 and Γ[Λ(1520) → Λγ] = 159 ± 35 keV (the quoted errors are purely statistical, the systematic errors being within 15%)

Constraining f(R gravity in solar system, cosmology and binary pulsar systems

Directory of Open Access Journals (Sweden)

Tan Liu

2018-02-01

Full Text Available The f(R gravity can be cast into the form of a scalar–tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general f(R gravity, using a scalar–tensor representation with the chameleon mechanism, we calculate the parametrized post-Newtonian parameters γ and β, the effective gravitational constant Geff, and the effective cosmological constant Λeff. In addition, for the general f(R gravity, we also calculate the rate of orbital period decay of the binary system due to gravitational radiation. Then we apply these results to specific f(R models (Hu–Sawicki model, Tsujikawa model and Starobinsky model and derive the constraints on the model parameters by combining the observations in solar system, cosmological scales and the binary systems.

Search for cluster decay of 230U

International Nuclear Information System (INIS)

Yang Weifan; Pan Qiangyan; Ma Taotao; Yuan Shuanggui; Guo Junsheng; Kong Dengming; Qiao Jimin; Luo Zihua; Zhang Motian; Wang Shuhong

2002-01-01

230 Pa can be produced via the 232 Th(p, 3n) reaction by 35 MeV proton bombardment of natural thorium. Pa is separated radiochemically and six thin sources of 230 Pa→(β) 230 U are prepared. The γ spectrum of Pa sources are measured by a HPGe detector. Using PETP track-recording films, the rare 22 Ne decay mode of 230 U is discovered for the first time. The branching ratio (B) relative to α decay is Bλ Ne /λ α = (1.3 +- 0.8) x 10 -14 for 230 U

On a possible method of experimental investigation of proton decay modes

International Nuclear Information System (INIS)

Gulkanyan, H.R.; Pogosov, V.S.; Tamanyan, A.G.

1982-01-01

A detector for experimental investigation of proton decay modes is described. The detector represents a multiwire high pressure gas chamber, located in an underground cavity in a rock salt layer, analogous to known underground artificial depositories of fuel gas. It allows to identify decay particles and reaction kinematics at the amount of working gas of several dozens of kilotons and more required for the proton decay detection at the half-lifetime tau > 10 33 years and investigation of decay modes at tau 33 years. The detector also permits to investigate other exotic events such as a search for fractional charge particles, neutrino oscillations

Direct measurement of the pseudoscalar decay constant, fDs

International Nuclear Information System (INIS)

Bai, J.Z.; Bardon, O.; Blum, I.; Breakstone, A.; Burnett, T.; Chen, G.P.; Chen, H.F.; Chen, J.; Chen, S.J.; Chen, S.M.; Chen, Y.; Chen, Y.B.; Chen, Y.Q.; Cheng, B.S.; Cowan, R.F.; Cui, H.C.; Cui, X.Z.; Ding, H.L.; Du, Z.Z.; Dunwoodie, W.; Fan, X.L.; Fang, J.; Fero, M.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gao, W.X.; Gratton, P.; Gu, J.H.; Gu, S.D.; Gu, W.X.; Gu, Y.F.; Guo, Y.N.; Han, S.W.; Han, Y.; Harris, F.A.; Hatanaka, M.; He, J.; He, K.R.; He, M.; Hitlin, D.G.; Hu, G.Y.; Hu, H.B.; Hu, T.; Hu, X.Q.; Huang, D.Q.; Huang, Y.Z.; Izen, J.M.; Jia, Q.P.; Jiang, C.H.; Jin, Y.; Jones, L.; Kang, S.H.; Kelsey, M.H.; Kim, B.K.; Lai, Y.F.; Lan, H.B.; Lang, P.F.; Lankford, A.; Li, F.; Li, J.; Li, P.Q.; Li, Q.; Li, R.B.; Li, W.; Li, W.D.; Li, W.G.; Li, X.; Li, X.N.; Lin, S.Z.; Liu, H.M.; Liu, J.H.; Liu, Q.; Liu, R.G.; Liu, Y.; Liu, Z.A.; Lou, X.C.; Lowery, B.; Lu, J.G.; Ma, A.M.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Malchow, R.; Mandelkern, M.; Meng, X.C.; Ni, H.L.; Nie, J.; Olsen, S.L.; Oyang, J.; Paluselli, D.; Pan, L.J.; Panetta, J.; Porter, F.; Prabhakar, E.; Qi, N.D.; Que, Y.K.; Quigley, J.; Rong, G.; Schernau, M.; Schmid, B.; Schultz, J.; Shao, Y.Y.; Shen, D.L.; Shen, H.; Shen, X.Y.; Sheng, H.Y.; Shi, H.Z.; Shi, X.R.; Smith, A.; Soderstrom, E.; Song, X.F.; Standifird, J.; Stoker, D.; Sun, F.; Sun, H.S.; Sun, S.J.; Synodinos, J.; Tan, Y.P.; Tang, S.Q.; Toki, W.; Tong, G.L.; Torrence, E.; Wang, F.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, T.J.; Wang, W.; Wang, Y.Y.; Whittaker, S.; Wilson, R.; Wisniewski, W.J.; Xi, D.M.; Xia, X.M.; Xie, P.P.; Xu, D.Z.; Xu, R.S.; Xu, Z.Q.; Xue, S.T.; Yamamoto, R.; Yan, J.; Yan, W.G.; Yang, C.M.; Yang, C.Y.; Yang, W.; Yao, H.B.; Ye, M.H.; Ye, S.Z.; Yu, C.S.; Yu, C.X.; Yu, Z.Q.; Yuan, C.Z.; Zhang, B.Y.; Zhang, C.C.; Zhang, D.H.; Zhang, H.L.; Zhang, J.; Zhang, J.W.; Zhang, L.S.; Zhang, S.Q.; Zhang, Y.; Zhang, Y.Y.; Zhao, D.X.; Zhao, J.W.; Zhao, M.; Zhao, P.D.; Zhao, W.R.; Zhao, W.X.; Zheng, J.P.

1995-01-01

The Beijing Spectrometer (BES) experiment has observed purely leptonic decays of the D s meson in the reaction e + e - →D s + D s - at a c.m. energy of 4.03 GeV. Three events are observed in which one D s decays hadronically to φπ, K 0 K, and the other decays leptonically to μν μ or τν τ . With the assumption of μ-τ universality, values of the branching fraction, B(D s →μν μ )=(1.5 -0.6-0.2 +1.3+0.3 )%, and the D s pseudoscalar decay constant, f D s =(4.3 -1.3-0.4 +1.5+0.4 )x10 2 MeV, are obtained

Asymmetry in nonmesonic decay of polarized sup 5 subLAMBDA He hypernucleus

CERN Document Server

Ajimura, S; Ejiri, H; Hasegawa, T; Hashimoto, O; Ishikawa, M; Ikeda, K; Kim, Y; Kishimoto, T; Maeda, K; Manabe, K; Nagae, T; Nakano, T; Noumi, H; Okusu, A; Park, H; Sekimoto, M; Shibata, T; Shinkai, N; Takahashi, T; Tanaka, Y; Youn, M

2000-01-01

We have measured the asymmetric emission of protons and pions from the non mesonic decay of the polarized sup 5 subLAMBDA He produced by the (pi sup + , K sup +) reaction. The polarization was derived by the observed asymmetry of the mesonic decay pions for the first time. The asymmetry parameter of the non mesonic decay has been evaluated using the obtained polarization and the asymmetry of the decay protons. The positive asymmetry parameter contradicts theoretical prediction based on meson exchange model. The discrepancy can be attributed to insufficient knowledge of the weak LAMBDA N interaction, especially at short range, which may consistently explain the discrepancy seen in the partial decay rates of the non mesonic decay.

Recent achievements in the Hamiltonian treatment of the dynamics and motion of compact binaries in general relativity

International Nuclear Information System (INIS)

Schäfer, Gerhard

2014-01-01

The current knowledge in the post-Newtonian (PN) dynamics and motion of non-spinning and spinning compact binaries will be presented based on the Arnowitt-Deser-Misner Hamiltonian approach to general relativity. The presentation will cover the binary dynamics with non-spinning components up to the 4PN order and for spinning binaries up to the next-to-next-to-leading order in the spin-orbit and spin-spin couplings. Radiation reaction will be treated for both non-spinning and spinning binaries. Explicit analytic expressions for the motion will be given, innermost stable circular orbits will be discussed

Models for the formation of binary and millisecond radio pulsars

International Nuclear Information System (INIS)

van den Heuvel, E.P.J.

1984-01-01

The peculiar combination of a relatively short pulse period and a relatively weak surface dipole magnetic field strength of binary radio pulsars finds a consistent explanation in terms of: (i) decay of the surface dipole component of neutron star magnetic fields on a timescale of (2-5).10 6 yrs, in combination with: (ii) spin up of the rotation of the neutron star during a subsequent mass-transfer phase. The two observed classes of binary radio pulsars (very close and very wide systems, respectively) are expected to have been formed by the later evolution of binaries consisting of a neutron star and a normal companion star, in which the companion was (considerably) more massive than the neutron star, or less massive than the neutron star, respectively. In the first case the companion of the neutron star in the final system will be a fairly massive white dwarf, in a circular orbit, or a neutron star in an eccentric orbit. In the second case the final companion to the neutron star will be a low-mass (approx. 0.3 Msub solar) helium white dwarf in a wide and nearly circular orbit. In systems of the second type the neutron star was most probably formed by the accretion-induced collapse of a white dwarf. This explains why PSR 1953+29 has a millisecond rotation period and why PSR 0820+02 has not. Binary coalescence models for the formation of the 1.5 millisecond pulsar appear to be viable. The companion to the neutron star may have been a low-mass red dwarf, a neutron star, or a massive (> 0.7 Msub solar) white dwarf. In the red-dwarf case the progenitor system probably was a CV binary in which the white dwarf collapsed by accretion. 66 references, 6 figures, 1 table

Complex fragments from excited actinide nuclei. A new test of the finite range model

International Nuclear Information System (INIS)

Sarantities, D.G.; Bowman, D.R.; Wozniak, G.J.; Charity, R.J.; Liu, Z.H.; McDonald, R.J.; McMahan, M.A.; Moretto, L.G.

1989-01-01

Complex fragments ranging in charge from 7 ≤ Z ≤ 45 have been detected in binary coincidence following the reaction of 8.4 MeV/u 232 Th+ 12 C, and are shown to arise from the binary decay of a 244 Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barriers. (orig.)

Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

International Nuclear Information System (INIS)

Tso, Kin.

1996-05-01

The 129 Xe-induced reactions on nat Cu, 89 Y, 165 Ho, and 197 Au at bombarding energies of E/A = 40 ampersand 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129 Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied

Scalar mesons and radiative vector meson decays

International Nuclear Information System (INIS)

Gokalp, A.; Ylmaz, O

2002-01-01

The light scalar mesons with vacuum quantum numbers J p =0 ++ have fundamental importance in understanding low energy QCD phenomenology and the symmetry breaking mechanisms in QCD. The nature and quark substructure of the best known scalar mesons, isoscalar σ(500), f0(980) and isovector a0(980) have been a subject of continuous controversy. The radioactive decay of neutral vector mesons ρ, w and φ into a single photon and a pair of neutral pseudoscalar mesons have been studied in order to obtain information on the nature of these scalar mesons. For such studies, it is essential that a reliable understanding of the mechanisms for these decays should be at hand. In this work, we investigate the particularly interesting mechanism of the exchange of scalar mesons for the radiative vector meson decays by analysing the experimental results such as measured decay rates and invariant mass spectra and compare them with the theoretical prediction of different reaction mechanisms

Radiative capture studies of the electromagnetic decays of highly excited states

Energy Technology Data Exchange (ETDEWEB)

Snover, K. A. [Washington Univ., Seattle (USA). Dept. of Physics; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

1980-01-01

Selected examples of interesting E1, M1 and E2 resonance studies in (p, ..gamma..) and (..cap alpha.., ..gamma..) reactions are discussed. These include a unique determination of E1 amplitudes in the /sup 12/C(p,..gamma..sub(o))/sup 13/N reaction, E2 strength in light nuclei, M1 decays to the ground states and to the excited O/sup +/ states of the doubly magic /sup 16/O and /sup 40/Ca nuclei, ''second harmonic'' E1 resonances in (p, ..gamma..), and M1 ..gamma..-decay of stretched particle-hole states in /sup 16/O and /sup 28/Si.

Decay properties of the key resonant states in 8Li(α,n)11B for primordial nucleosynthesis

International Nuclear Information System (INIS)

Kubono, S.; Ikeda, N.; Tanaka, M.H.; Nomura, T.; Katayama, I.; Fuchi, Y.; Kawashima, H.; Kajino, T.

1991-01-01

The particle decay property of the key resonant states in the reaction 8 Li(α, n) 11 B for the inhomogeneous big bang models was studied experimentally. The sum of the branching ratios of the 10.572 MeV state for the neutron decays to the excited states in 11 B is as large as for the ground state, indicating that the neutron decays to excited states are crucial and enhance the reaction rate for heavy element synthesis considerably. (orig.)

Decay to Equilibrium for Energy-Reaction-Diffusion Systems

KAUST Repository

Haskovec, Jan

2018-02-06

We derive thermodynamically consistent models of reaction-diffusion equations coupled to a heat equation. While the total energy is conserved, the total entropy serves as a driving functional such that the full coupled system is a gradient flow. The novelty of the approach is the Onsager structure, which is the dual form of a gradient system, and the formulation in terms of the densities and the internal energy. In these variables it is possible to assume that the entropy density is strictly concave such that there is a unique maximizer (thermodynamical equilibrium) given linear constraints on the total energy and suitable density constraints. We consider two particular systems of this type, namely, a diffusion-reaction bipolar energy transport system, and a drift-diffusion-reaction energy transport system with confining potential. We prove corresponding entropy-entropy production inequalities with explicitly calculable constants and establish the convergence to thermodynamical equilibrium, first in entropy and later in L norm using Cziszár–Kullback–Pinsker type inequalities.

Decay to Equilibrium for Energy-Reaction-Diffusion Systems

KAUST Repository

Haskovec, Jan; Hittmeir, Sabine; Markowich, Peter A.; Mielke, Alexander

2018-01-01

We derive thermodynamically consistent models of reaction-diffusion equations coupled to a heat equation. While the total energy is conserved, the total entropy serves as a driving functional such that the full coupled system is a gradient flow. The novelty of the approach is the Onsager structure, which is the dual form of a gradient system, and the formulation in terms of the densities and the internal energy. In these variables it is possible to assume that the entropy density is strictly concave such that there is a unique maximizer (thermodynamical equilibrium) given linear constraints on the total energy and suitable density constraints. We consider two particular systems of this type, namely, a diffusion-reaction bipolar energy transport system, and a drift-diffusion-reaction energy transport system with confining potential. We prove corresponding entropy-entropy production inequalities with explicitly calculable constants and establish the convergence to thermodynamical equilibrium, first in entropy and later in L norm using Cziszár–Kullback–Pinsker type inequalities.

Statistical gamma-ray decay studies at iThemba LABS

Directory of Open Access Journals (Sweden)

Wiedeking M.

2017-01-01

Full Text Available A program to study the γ-ray decay from the region of high-level density has been established at iThemba LABS, where a high-resolution gamma-ray detector array is used in conjunction with silicon particle-telescopes. Results from two recent projects are presented: 1 The 74Ge(α,α′γ reaction was used to investigate the Pygmy Dipole Resonance. The results were compared to (γ,γ′ data and indicate that the dipole states split into mixed isospin and relatively pure isovector excitations. 2 Data from the 95Mo(d,p reaction were used to develop a novel method for the determination of spins for low-lying discrete levels utilizing statistical γ-ray decay in the vicinity of the neutron separation energy. These results provide insight into the competition of (γ,n and (γ,γ′ reactions and highlights the need to correct for angular momentum barrier effects.

Alpha decay 225 Ac → 221Fr

International Nuclear Information System (INIS)

Gromov, K. Ya.; Gorozhankin, V.M.; Malov, L.A.; Fominykh, V.I.; Tsupko-Sitnikov, V.V.; Chumin, V.G.; Jakushev, E.A.; Kudrya, S.A.; Sergienko, V.A.; Malikov, Sh.R.

2004-01-01

Full text: Considerable attention has been given to nuclei with A = 220 - 230 recently. In this region there occurs transition from the spherical to the deformed nuclear shape, which gives rise to some specific features in the nuclear structure. In particular, negative parity levels with low excitation energies have been found in even-even nuclei from this region [1, 2]. One of the nuclei allowing experimental investigation of the above properties is 221 Fr. The nuclide 221 Fr is from the region of isotopes which does not include stable nuclei and thus it cannot be studied in several-nucleon transfer reactions. In addition, the neutron excess in this nucleus makes it impossible to study the nucleus in reactions with heavy ions. Experimental information on the 221 Fr level structure can only be gained from investigation of the 225 Ac (T 1/2 = 10 days) alpha decay or the 221 Rn (T 1/2 = 25 min) beta decay. In the latter case the possibilities of the investigation are restricted by difficulties in making of 221 Rn sources. Therefore, most information on the structure and properties of 221 Fr is derived from investigation of the 225 Ac α -decay [3]. In-depth investigation of ( α - γ )- coincidences at the 225 Ac decay is carried out. Twenty-one new weak γ - rays are found; 18 γ-rays earlier ascribed to the 225 Ac decay are not confirmed. The quantitative analysis of the ( α - γ )- coincidences makes it possible to find the intensity of 221 Fr levels by the decay and multipolarities of five weak γ -transitions. The conversion electron spectrum is investigated in the range of 5 † 24 keV with a high (some 20 eV) energy resolution. A new M1 type 10.6-keV γ-transition is found. The proposed 225 Ac decay scheme includes 31 excited 221 Fr states. Parities are established for 16 of them. Possible spin values are proposed for 221 Fr levels. Properties of excited 221 Fr states are satisfactorily described by the quasiparticle-phonon nuclear model without the

Nuclear Reaction Data Centers

International Nuclear Information System (INIS)

McLane, V.; Nordborg, C.; Lemmel, H.D.; Manokhin, V.N.

1988-01-01

The cooperating Nuclear Reaction Data Centers are involved in the compilation and exchange of nuclear reaction data for incident neutrons, charged particles and photons. Individual centers may also have services in other areas, e.g., evaluated data, nuclear structure and decay data, reactor physics, nuclear safety; some of this information may also be exchanged between interested centers. 20 refs., 1 tab

Study of 16O-induced deep inelastic nuclear reactions on 27Al, 48Ti, and 58Ni by spectroscopy of the gamma radiation from the reaction products

International Nuclear Information System (INIS)

Puchta, H.

1980-01-01

The present thesis deals with the spectroscopy of the gamma radiation from the reaction fragments after binary reactions in the systems 16 O + 27 Al, 48 Ti, and 58 Ni at incident energies from 90 to 100 MeV, i.e. far above the Coulomb threshold. ΔE-E telescopes, which were located at 35 0 to the beam direction, detected the projectile-like fragments and defined the reaction channel and the scattering plane. In coincidence to this the gamma quanta in a 120-cm 3 -Ge(Li)-diode and a 27 x 33-cm-NaI-spectrometer were observed. The gamma spectra are equal to those observed hitherto in fusion reactions except for the high energetic gamma lines from the ejectiles, which are raised from the gamma continuum of the heavy fragments. From the spectroscoped gamma radiation for the light as for the heavy fragments the excitation energy, the value of the fragment angular momentum, as well as the occupation of the magnetic sublevels could be determined. The hard projectile 16 O transfers the dissipated energy and the angular momentum transferred by the spin of the fragments nearly completely into the residue nucleus. The probability for the observation of a ground state transition in one of the heavy fragments extends to (0.85 +- 0.10) per carbon ejectile in the system 16 O + 48 Ti. The residue nucleus distribution corresponds to that expected by the statistical model from the decay of the compound-nucleus 52 Cr belonging to the ejectile 12 C, the excitation energy of which corresponds to the reaction Q-value. (orig./HSI) [de

Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains

Energy Technology Data Exchange (ETDEWEB)

Rudolph, D. [Lund Univ., Lund (Sweden); Forsberg, U. [Lund Univ., Lund (Sweden); Golubev, P. [Lund Univ., Lund (Sweden); Sarmiento, L. G. [Lund Univ., Lund (Sweden); Yakushev, A. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Andersson, L. -L. [Helmholtz Institute Mainz, Mainz (Germany); Di Nitto, A. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Dullmann, Ch. E. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Gates, J. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gregorich, K. E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gross, C. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herzberg, R. -D. [Univ. of Liverpool, Liverpool (United Kingdom); Hessberger, F. P. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institute Mainz, Mainz (Germany); Khuyagbaatar, J. [Helmholtz Institute Mainz, Mainz (Germany); Kratz, J. V. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Rykaczewski, K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schadel, M. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Japan Atomic Energy Agency, Tokai (Japan); Aberg, S. [Lund Univ., Lund (Sweden); Ackermann, D. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Block, M. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Brand, H. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Carlsson, B. G. [Lund Univ., Lund (Sweden); Cox, D. [Univ. of Liverpool, Liverpool (United Kingdom); Derkx, X. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Eberhardt, K. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Even, J. [Helmholtz Institute Mainz, Mainz (Germany); Fahlander, C. [Lund Univ., Lund (Sweden); Gerl, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Jager, E. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kindler, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Krier, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kojouharov, I. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kurz, N. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Lommel, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Mistry, A. [Univ. of Liverpool, Liverpool (United Kingdom); Mokry, C. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Nitsche, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Omtvedt, J. P. [Univ. of Oslo, Oslo (Norway); Papadakis, P. [Univ. of Liverpool, Liverpool (United Kingdom); Ragnarsson, I. [Lund Univ., Lund (Sweden); Runke, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Schaffner, H. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Schausten, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Thorle-Pospiech, P. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Torres, T. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Traut, T. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Trautmann, N. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Turler, A. [Paul Scherrer Institute and Univ. of Bern, Villigen (Switzerland); Ward, A. [Univ. of Liverpool, Liverpool (United Kingdom); Ward, D. E. [Lund Univ., Lund (Sweden); Wiehl, N. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany)

2014-01-01

Produced in the reaction ⁴⁸Ca+ ²⁴³Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum für Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.

Study of $\\beta$-delayed neutron decay of $^{8}$He

CERN Multimedia

The goal of the present proposal is to study $\\beta$-delayed neutron decay branch of $^{8}$He. The energy spectra of the emitted neutrons will be measured in the energy range of 0.1 – 6 MeV using the VANDLE spectrometer. Using coincident $\\gamma$-ray measurement, components of the spectrum corresponding to transitions to the ground- and first- excited states of $^{7}$Li will be disentangled. The new data will allow us to get a more complete picture of the $\\beta$-decay of $^{8}$He and to clarify the discrepancy between the B(GT) distributions derived from the $\\beta$-decay and $^{8}$He(p, n)$^{8}$Li reaction studies.

The π+-emission puzzle in 4 over Lambda He decay

International Nuclear Information System (INIS)

Gibson, B.F.; Timmermans, R.

1997-10-01

The observed π + emission from the weak decay of 4 over Λ He has long been an intriguing puzzle. Experimentally, the π + to π - ratio for 4 over Λ He decay is about 5%. Because mesonic decay modes of the free Λ (→ p + π - , n + π 0 ) produce no π + s, more complicated mechanisms must be responsible for the π + decay of 4 over Λ He. Dalitz and von Hippel explored two-body decay processes of the type: (1) Λ → π 0 + n decay followed by a π 0 + p → π + + n charge-exchange reaction, and (2) Σ + → π + + n decay following a Λ + p → Σ + + n conversion. They concluded that neither process could account for even a 1% π + + n decay as a p-wave process ruled out the promising explanation coming from von Hippel's calculations, which had found that s-wave Σ + decay might yield a sufficiently high rate. Cieply and Gal re-examined the charge-exchange contribution and concluded that, although up-to-date input parameters yield a 1.2% branching ratio, the charge-exchange mechanism cannot account for the experimental value of about 5%

CHARACTERIZING THE GALACTIC WHITE DWARF BINARY POPULATION WITH SPARSELY SAMPLED RADIAL VELOCITY DATA

International Nuclear Information System (INIS)

Maoz, Dan; Badenes, Carles; Bickerton, Steven J.

2012-01-01

We present a method to characterize statistically the parameters of a detached binary sample—binary fraction, separation distribution, and mass-ratio distribution—using noisy radial velocity data with as few as two, randomly spaced, epochs per object. To do this, we analyze the distribution of ΔRV max , the maximum radial velocity difference between any two epochs for the same object. At low values, the core of this distribution is dominated by measurement errors, but for large enough samples there is a high-velocity tail that can effectively constrain the parameters of the binary population. We discuss our approach for the case of a population of detached white dwarf (WD) binaries with separations that are decaying via gravitational wave emission. We derive analytic expressions for the present-day distribution of separations, integrated over the star formation history of the Galaxy, for parameterized initial WD separation distributions at the end of the common-envelope phase. We use Monte Carlo techniques to produce grids of simulated ΔRV max distributions with specific binary population parameters, and the same sampling cadences and radial velocity errors as the observations, and we compare them to the real ΔRV max distribution to constrain the properties of the binary population. We illustrate the sensitivity of the method to both the model and observational parameters. In the particular case of binary WDs, every model population predicts a merger rate per star which can easily be compared to specific Type Ia supernova rates. In a companion paper, we apply the method to a sample of ∼4000 WDs from the Sloan Digital Sky Survey. The binary fractions and separation distribution parameters allowed by the data indicate a rate of WD-WD mergers per unit stellar mass in the Galactic disk, ∼1 × 10 –13 mergers yr –1 M –1 ☉ , remarkably similar to the rate per unit mass of Type Ia supernovae in Milky Way like galaxies.

Gluon fragmentation in T(1S) decays

International Nuclear Information System (INIS)

Bienlein, J.K.

1983-05-01

In T(1S) decays most observables (sphericity, charged multiplicity, photonic energy fraction, inclusive spectra) can be understood assuming that gluons fragment like quarks. New results from LENA use the (axis-independent) Fox-Wolfram moments for the photonic energy deposition. Continuum reactions show 'standard' Field-Feynman fragmentation. T(1S) decays show a significant difference in the photonic energy topology. It is more isotropic than with the Field-Feynman fragmentation scheme. Gluon fragmentation into isoscalar mesons (a la Peterson and Walsh) is excluded. But if one forces the leading particle to be isoscalar, one gets good agreement with the data. (orig.)

Use of linear regression for the processing of curves of differential potentiometric titration of a binary mixture of heterovalent ions using precipitation reactions

International Nuclear Information System (INIS)

Mar'yanov, B.M.; Zarubin, A.G.; Shumar, S.V.

2003-01-01

A method is proposed for the computer processing of curve of differential potentiometric titration of a binary mixture of heterovalent ions using precipitation reactions. The method is based on the transformation of the titration curve to segment-line characteristics, whose parameters (within the accuracy of the least-squares method) determine the sequence of the equivalence points and solubility products of the resulting precipitation. The method is applied to the titration of Ag(I)-Cd)II), Hg(II)-Te(IV), and Cd(II)-Te(IV) mixtures by a sodium diethyldithiocarbamate solution with membrane sulfide and glassy carbon indicator electrodes. For 4 to 11 mg of the analyte in 50 ml of the solution, RSD varies from 1 to 9% [ru

Complex fragments from excited actinide nuclei: A new test of the finite range model

International Nuclear Information System (INIS)

Sarantities, D.G.; Bowman, D.R.; Wozniak, G.J.; Charity, R.J.; Liu, Z.H.; McDonald, R.J.; McMahan, M.A.; Moretto, L.G.

1988-05-01

Complex fragments ranging in charge from 7≤Z≤45 have been detected in binary coincidence following the reaction of 8.4 MeV/u 232 Th+ 12 C, and are shown to arise from the binary decay of a 244 Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barriers. 15 refs., 3 figs

Percolation of binary disk systems: Modeling and theory

International Nuclear Information System (INIS)

Meeks, Kelsey; Pantoya, Michelle L.

2017-01-01

The dispersion and connectivity of particles with a high degree of polydispersity is relevant to problems involving composite material properties and reaction decomposition prediction and has been the subject of much study in the literature. This paper utilizes Monte Carlo models to predict percolation thresholds for a two-dimensional systems containing disks of two different radii. Monte Carlo simulations and spanning probability are used to extend prior models into regions of higher polydispersity than those previously considered. A correlation to predict the percolation threshold for binary disk systems is proposed based on the extended dataset presented in this work and compared to previously published correlations. Finally, a set of boundary conditions necessary for a good fit is presented, and a condition for maximizing percolation threshold for binary disk systems is suggested.

Statistical and direct decay of high-lying single-particle excitations

International Nuclear Information System (INIS)

Gales, S.

1993-01-01

Transfer reactions induced by hadronic probes at intermediate energies have revealed a rich spectrum of high-lying excitations embedded in the nuclear continuum. The investigation of their decay properties is believed to be a severe test of their microscopic structure as predicted by microscopic nuclear models. In addition the degree of damping of these simple modes in the nuclear continuum can be obtained by means of the measured particle (n,p) decay branching ratios. The neutron and proton decay studies of high-lying single-particle states in heavy nuclei are presented. (author). 13 refs., 9 figs

SIMULTANEOUS MEASUREMENT OF FREE RADICAL DECAY IN POLYMERIZATION OF MMA INITIATED BY AIBN USING ESR AND ITS KINETIC MODEL

Institute of Scientific and Technical Information of China (English)

Ping Xia; Qing-song Hu; Xiao-lan Qian; Xul-in Jiang; De-yue Yan

2001-01-01

The kinetics of free radical decay in the polymerization of MMA initiated by AIBN was studied by means of ESR spectroscopy. It was found that the curves of radical decay are strongly associated with the reaction temperature, the initiator concentration and the solvent. In the case of the radical polymerization carried out at high temperature or in solution, the radical concentration first reached a maximum, then declined monotonously with reaction time. It was also found that the greater the amount of initiator or the higher the temperature, the more rapidly the radicals decay. When the bulk polymerization was implemented at a relatively low temperature, the curves of radical decay became more complicated, i.e.,the radical concentration rapidly rose to a maximum, then dropped to a minimum, finally increased again with reaction time.Taking into account the diffusion effect, a semi-empirical equation is suggested to describe the kinetics of propagating radical decay.

The new isotope 270110 and its decay products 266Hs and 262Sg

International Nuclear Information System (INIS)

Hofmann, S.; Hessberger, F.P.; Ackermann, D.

2000-11-01

The even-even nucleus 270 110 was synthesized using the reaction 64 Ni + 207 Pb. A total of eight α-decay chains was measured during an irradiation time of seven days. Decay data were obtained for the ground-state and a high spin K isomer. The new nuclei 266 Hs and 262 Sg were identified as daughter products after α decay. Spontaneous fission of 262 Sg terminates the decay chain. The measured data are in agreement with calculations using the macroscopic-microscopic model and with self-consistent HFB calculations with Skyrme-Sly4 interaction. (orig.)

Searching for Rapid Orbital Decay of WASP-18b

Science.gov (United States)

Wilkins, Ashlee N.; Delrez, Laetitia; Barker, Adrian J.; Deming, Drake; Hamilton, Douglas; Gillon, Michael; Jehin, Emmanuel

2017-02-01

The WASP-18 system, with its massive and extremely close-in planet, WASP-18b (M p = 10.3M J , a = 0.02 au, P = 22.6 hr), is one of the best-known exoplanet laboratories to directly measure Q‧, the modified tidal quality factor and proxy for efficiency of tidal dissipation, of the host star. Previous analysis predicted a rapid orbital decay of the planet toward its host star that should be measurable on the timescale of a few years, if the star is as dissipative as is inferred from the circularization of close-in solar-type binary stars. We have compiled published transit and secondary eclipse timing (as observed by WASP, TRAPPIST, and Spitzer) with more recent unpublished light curves (as observed by TRAPPIST and Hubble Space Telescope) with coverage spanning nine years. We find no signature of a rapid decay. We conclude that the absence of rapid orbital decay most likely derives from Q‧ being larger than was inferred from solar-type stars and find that Q‧ ≥ 1 × 106, at 95% confidence; this supports previous work suggesting that F stars, with their convective cores and thin convective envelopes, are significantly less tidally dissipative than solar-type stars, with radiative cores and large convective envelopes.

Isotopic yield in cold binary fission of even-even 230-244U isotopes

International Nuclear Information System (INIS)

Cyriac, Annu; Krishnan, Sreejith; Santhosh, K.P.

2017-01-01

The binary fission of even-even 230-244 U isotopes has been studied using the concept of cold reaction valley which was introduced in relation to the structure of minima in the so called driving potential

Chemical Identification of Dubnium as a Decay Product of Element 115 Produced in the Reaction $\\rm {^{48}Ca}+{^{243}Am}$

CERN Document Server

Dmitriev, S N; Utyonkov, V K; Shishkin, S V; Eremin, A V; Lobanov, Yu V; Chepigin, V I; Sokol, E A; Tsyganov, Yu S; Vostokin, G K; Aksenov, N V; Hussonnois, M; Itkis, M G; Aggeler, H W; Schumann, D; Bruchertseifer, H; Eichler, R; Shaughnessy, D A; Wilk, P A; Kenneally, J M; Stoyer, M A; Wild, J F

2004-01-01

The results of an experiment designed to identify $^{268}$Db as the terminal isotope in the $\\alpha $-decay chain of element 115 produced via the ${\\rm {^{243}Am}}({\\rm {^{48}Ca}},3n){\\rm {^{288}115}}$ reaction are presented. The $^{243}$Am target was bombarded with a beam dose of $3.4\\cdot 10^{18}$ $^{48}$Ca projectiles at an energy of 247 MeV at the center of the target. The reaction products were collected in the surface layer of a copper catcher block, which was removed with a lathe and then dissolved in concentrated HNO$_{3}$. The group-5 elements were separated by sorption onto Dowex $50{\\times} 8$ cation-exchange resin with subsequent desorption using 1 M HF, which forms anionic fluoride complexes of group-5 elements. The eluent was evaporated onto a 0.4 $\\mu$m thick polyethylene foil that was placed between a pair of semiconductor detectors surrounded by $^{3}$He neutron counters for measurement of $\\alpha$ particles, fission fragments, and neutrons. In the course of the experiment, we observed 15 spo...

Selected spectroscopic results on element 115 decay chains

International Nuclear Information System (INIS)

Rudolph, D.; Forsberg, U.; Golubev, P.; Sarmiento, L.G.; Yakushev, A.; Andersson, L.L.; Di Nitto, A.; Duellmann, Ch.E.; Gates, J.M.; Gregorich, K.E.

2015-01-01

Thirty correlated α-decay chains were observed in an experiment studying the fusion-evaporation reaction 48 Ca + 243 Am at the GSI Helmholtzzentrum fuer Schwerionenforschung. The decay characteristics of the majority of these 30 chains are consistent with previous observations and interpretations of such chains to originate from isotopes of element Z = 115. High-resolution α-photon coincidence spectroscopy in conjunction with comprehensive Monte-Carlo simulations allow to propose excitation schemes of atomic nuclei of the heaviest elements, thereby probing nuclear structure models near the 'Island of Stability' with unprecedented experimental precision. (author)

Study of the surrogate-reaction method applied to neutron-induced capture cross sections

International Nuclear Information System (INIS)

Boutoux, G.; Jurado, B.; Méot, V.; Roig, O.; Mathieu, L.; Aïche, M.; Barreau, G.; Capellan, N.; Companis, I.; Czajkowski, S.; Schmidt, K.-H.; Burke, J.T.; Bail, A.; Daugas, J.M.; Faul, T.; Morel, P.; Pillet, N.; Théroine, C.; Derkx, X.; Sérot, O.

2012-01-01

Gamma-decay probabilities of 173 Yb and 176 Lu have been measured using the surrogate reactions 174 Yb( 3 He,αγ) 173 Yb* and 174 Yb( 3 He,pγ) 176 Lu*, respectively. For the first time, the gamma-decay probabilities have been obtained with two independent experimental methods based on the use of C 6 D 6 scintillators and Germanium detectors. Our results for the radiative-capture cross sections are several times higher than the corresponding neutron-induced data. To explain these differences, we have used our gamma-decay probabilities to extract rather direct information on the spin distributions populated in the transfer reactions used. They are about two times wider and the mean values are 3 to 4 ℏ higher than the ones populated in the neutron-induced reactions. As a consequence, in the transfer reactions neutron emission to the ground and first excited states of the residual nucleus is strongly suppressed and gamma-decay is considerably enhanced.

Pulsars in binary systems: probing binary stellar evolution and general relativity.

Science.gov (United States)

Stairs, Ingrid H

2004-04-23

Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

Beta-delayed particle decay of 17Ne

International Nuclear Information System (INIS)

Morton, A.C.; Chow, J.C.; King, J.D.; Boyd, R.N.; Bateman, N.P.T.; Buchmann, L.; D'Auria, J.M.; Davinson, T.; Dombsky, M.; Galster, W.; Gete, E.; Giesen, U.; Iliadis, C.; Jackson, K.P.; Powell, J.; Roy, G.; Shotter, A.

2002-01-01

The β-delayed particle decay of 17 Ne has been studied via proton-γ coincidences, time-of-flight measurements and the ''ratio-cut technique'', allowing cleanly-separated proton and α-particle spectra to be obtained. A complete set of proton and α branching ratios for the decay of 14 excited states in 17 F to the ground and excited states of 16 O and 13 N has been determined and branching ratios for the β decay of 17 Ne to these states have been deduced. From the branching ratios, f A t values and reduced Gamow-Teller matrix elements were calculated; no indication of isospin mixing in the isobaric analog state in 17 F was observed. From the measurement of proton-γ angular correlations, combined with the selection rules for an allowed β decay, we obtain J π =((1)/(2)) - for states at 8.436 and 9.450 MeV and ((3)/(2)) - for the state at 10.030 MeV in 17 F. Probabilities for the β-delayed pα decay to 12 C through the tails of the subthreshold 7.117 and 6.917 MeV states in 16 O have been calculated and the feasibility of using such decays to provide information about the rates for the E1 and E2 components of the 12 C(α,γ) 16 O reaction is discussed

Trojan horse particle invariance studied with the 6Li(d,α)4He and 7Li(p,α)4He reactions

International Nuclear Information System (INIS)

Pizzone, R. G.; Spitaleri, C.; Lamia, L.; Cherubini, S.; La Cognata, M.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Burjan, V.; Hons, Z.; Kroha, V.; Mrazek, J.; Piskor, S.; Kiss, G. G.; Li, C.; Tumino, A.

2011-01-01

The Trojan horse nucleus invariance for the binary reaction cross section extracted from the Trojan horse reaction was tested using the quasifree 3 He( 6 Li,αα)H and 3 He( 7 Li,αα) 2 H reactions. The cross sections for the 6 Li(d,α) 4 He and 7 Li(p,α) 4 He binary processes were extracted in the framework of the plane wave approximation. They are compared with direct behaviors as well as with cross sections extracted from previous indirect investigations of the same binary reactions using deuteron as the Trojan horse nucleus instead of 3 He. The very good agreement confirms the applicability of the plane wave approximation which suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus, at least for the investigated cases.

Study of the multi-fragment production in asymmetric heavy ion reactions at E/A = 600 MeV

International Nuclear Information System (INIS)

Hubele, J.C.

1992-03-01

In this thesis the fragmentation of Au projectiles in collisions with light target nuclei ( 12 C, 27 Al, 64 Cu) is studied at a projectile energy of 600 MeV per nucleon. For the description of an event three observables are used: the multiplicity M lp of the light particles, the largest observed charge Z max of the projectile fragments, as well as a newly introduced obsevable Z bound , which is defined as the sum of all charge contained in complex projectile fragments (Z ≥ 2). By means of this observable different exit channels can be identified: the formation of a heavy residual nucleus by evaporation of light particles, the binary fission, the decay into IMF's (3 ≤ Z ≤ 30) and the complete decay into light particles. At the applied incident energy in the case of Au+Cu reactions each of these decay channels can be realized. The observables Z bound and M lpp are proved as suited quantities for the reconstruction of the impact parameter. Furthermore independently on the target a universal relation between Z bound and the multiplicity distribution of medium-heavy fragments is found. By simple model assumptions it is made plausible that Z bound is correlated both with the size of the projectile residue and in the mean with its excitation energy. For the characterization of the decay into IMF's the multiplicity M imf of these fragments is applied. For all three targets with increasing centrality first an increasing of the mean fragment multiplicities to maximal values of 3-4 is observed. In the case of the Cu target and suggestively also at the Al target in the most central collisions again a decreasing of the multiplicity is found. The universal Z bound behaviour is a hint to a - at least partial - equilibration of the primary projectile residue before the decay. (HSI) [de

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

Directory of Open Access Journals (Sweden)

Morelli L.

2014-03-01

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

Study of fragmentation reactions of light nucleus

International Nuclear Information System (INIS)

Toneli, David Arruda; Carlson, Brett Vern

2011-01-01

Full text: The decay of the compound nucleus is traditionally calculated using a sequential emission model, such as the Weisskopf-Ewing or Hauser-Feshbach ones, in which the compound nucleus decays through a series of residual nuclei by emitting one particle at a time until there is no longer sufficient energy for further emission. In light compound nucleus, however, the excitation energy necessary to fully disintegrate the system is relatively easy to attain. In such cases, decay by simultaneous emission of two or more particles becomes important. A model which takes into account all these decay is the Fermi fragmentation model. Recently, the equivalence between the Fermi fragmentation model and statistical multifragmentation model used to describe the decay for highly excited fragments for reactions of heavy ions was demonstrated. Due the simplicity of the thermodynamic treatment used in the multifragmentation model, we have adapted it to the calculation of Fermi breakup of light nuclei. The ultimate goal of this study is to calculate the distribution of isotopes produced in proton-induced reactions on light nuclei of biological interest, such as C, O e Ca. Although most of these residual nuclei possess extremely short half-lives and thus represent little long-term danger, they tend to be deficient in neutrons and to decay by positron emission, which allows the monitoring of proton radiotherapy by PET (Positron Emission Tomography). (author)

Decay of new mass-separated neutron-deficient La and Ce isotopes

International Nuclear Information System (INIS)

Genevey, J.; Gizon, A.; Idrissi, N.; Weiss, B.; Beraud, R.; Charvet, A.; Duffait, R.; Emsallem, A.; Meyer, M.; Ollivier, T.; Redon, N.

1987-01-01

By use of a He jet system coupled to a Bernas-Nier ion-source, several new mass-separated A = 122 - 127 isotopes reached in heavy ion fusion reactions at SARA have been identified and studied. From experimental decay properties of La isotopes, systematics of low-lying energy levels have been extended for even-even and odd-A barium. New informations on Ce decay schemes are briefly reported

Absolute measurement of the $\\beta\\alpha$ decay of $^{16}$N

CERN Multimedia

We propose to study the $\\beta$-decay of $^{16}$N at ISOLDE with the aim of determining the branching ratio for $\\beta\\alpha$ decay on an absolute scale. There are indications that the previously measured branching ratio is in error by an amount significantly larger than the quoted uncertainty. This limits the precision with which the S-factor of the astrophysically important $^{12}$C($\\alpha, \\gamma)^{16}$O reaction can be determined.

Trojan Binaries

Science.gov (United States)

Noll, K. S.

2017-12-01

The Jupiter Trojans, in the context of giant planet migration models, can be thought of as an extension of the small body populations found beyond Neptune in the Kuiper Belt. Binaries are a distinctive feature of small body populations in the Kuiper Belt with an especially high fraction apparent among the brightest Cold Classicals. The binary fraction, relative sizes, and separations in the dynamically excited populations (Scattered, Resonant) reflects processes that may have eroded a more abundant initial population. This trend continues in the Centaurs and Trojans where few binaries have been found. We review new evidence including a third resolved Trojan binary and lightcurve studies to understand how the Trojans are related to the small body populations that originated in the outer protoplanetary disk.

Nuclear fragmentation for Xe+Au and Xe+Ag systems at an energy of 44 A.MeV, formation and decay of hot nuclei; Etude de la fragmentation nucleaire pour les systemes XE+AU et XE+AG a 44 A.MeV, production et decroissance de noyaux chauds

Energy Technology Data Exchange (ETDEWEB)

Meslin, C.

1995-01-01

A study of the formation and the decay of hot nuclear fragments produced in the reactions Xe+Au and Xe+Ag at an energy of 44 A.MeV is presented in this thesis. The 4{pi} experimental setup consisted of four multidetectors -two for the detection of the fragments (Z>7; DELF and XYZT) and two for the detection of the charged particles (Z<6; MUR and TONNEAU) and allowed an analysis using ``complete events`` (80 % of the total charge and the total parallel linear momentum of the entrance channel) to be carried out. The reaction mechanism is binary with as observed at low energy an almost complete relaxation of the incident energy. The collision results in two hot fragments at the beginning of the exit channel which decay by evaporation and/or fragmentation. In addition of these two body events, we have identified a new dynamic mechanism where we detect a small fragment, called the neck, coming form the overlap of the nuclei during the interaction, in coincidence with a projectile-like fragment and a target-like fragment. For the most dissipative collisions, the deep inelastic collision have allowed an estimation of the lifetime of the hot nuclear fragments to be made. This is possible using proximity effects and fragment-fragment space-time correlations of the decay of one or two primary partners from the deep inelastic collisions. This method is seen to reach its limits in the case of the reactions studied here. (authors). 61 refs.

Perspectives of Scalar- and Vector- Meson Production in Hadron-Nucleus Reactions

International Nuclear Information System (INIS)

Cassing, W.

2000-01-01

The production and decay of vector mesons (ρ, ω) in pA reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium decays like π + π - or π 0 γ might provide complementary information to their dilepton (e + e - ) decays. Whereas the π + π - signal from the ρ-meson is found to be strongly distorted by pion rescattering, the ω- meson Dalitz decay to π 0 γ appears promising even for more heavy nuclei. The perspectives of scalar meson ( f 0 , a 0 ) production in pp reactions are investigated within a boson-exchange model indicating that the f 0 -meson might hardly be detected in these collisions in the K(anti)K or ππ decay channels whereas the exclusive channel pp→da 0 + looks very promising. (author)

Reaction diffusion and solid state chemical kinetics handbook

CERN Document Server

Dybkov, V I

2010-01-01

This monograph deals with a physico-chemical approach to the problem of the solid-state growth of chemical compound layers and reaction-diffusion in binary heterogeneous systems formed by two solids; as well as a solid with a liquid or a gas. It is explained why the number of compound layers growing at the interface between the original phases is usually much lower than the number of chemical compounds in the phase diagram of a given binary system. For example, of the eight intermetallic compounds which exist in the aluminium-zirconium binary system, only ZrAl3 was found to grow as a separate

The synthesis and decay properties of the heaviest elements

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the 'islands of stability' of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus 208 Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with 48 Ca. In these reactions the decay chains of heavy atoms consisting of sequential α-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first experimental evidence of the existence of domains of stability of superheavy nuclei which substantially extends the boundaries of existence of chemical elements

Decay properties of nuclei close to Z = 108 and N = 162

International Nuclear Information System (INIS)

Dvorak, Jan

2007-01-01

The goal of the research conducted in the frame of this thesis was to investigate the decay properties of the nuclides 269-271 Hs and their daughters using an improved chemical separation and detection system. Shell stabilization was predicted in the region around Z=108 and N=162 in calculations, taking into account possible higher orders of deformations of the nuclei. The nucleus 270 Hs with a closed proton and a closed neutron deformed shell, was predicted to be ''deformed doubly magic''. Nuclei around 270 Hs can be produced only via fusion reactions at picobarn levels, resulting in a production rates of few atoms per day. Investigating short-lived nuclei using rapid chemical separation and subsequent on-line detection methods provides an independent and alternative means to electromagnetic on-line separators. Chemical separation of Hs in the form of HsO 4 provides an excellent tool to study the formation reactions and nuclear structure in this region of the chart of nuclides due to a high overall efficiency and a very high purification factor. The goal was accomplished, as element 108, hassium, was produced in the reaction 248 Cm( 26 Mg,xn) 274-x Hs and chemically isolated. After gas phase separation of HsO 4 , 26 genetically linked decay chains have been observed. These were attributed to decays of three different Hs isotopes produced in the 3-5n evaporation channels. The known decay chain of 269 Hs, the 5n evaporation product, serves as an anchor point, thus allowing the unambiguous assignment of the observed decay chains to the 5n, 4n, and 3n channels, respectively. Decay properties of five nuclei have been unambiguously established for the first time, including the one for the the doubly-magic nuclide 270 Hs. This hassium isotope is the next doubly magic nucleus after the well known 208 Pb and the first experimentally observed even-even nucleus on the predicted N=162 neutron shell. The observed decay properties provide strong indications for enhanced nuclear

Multifragmentation in intermediate energy ¹²⁹Xe-induced heavy-ion reactions

Energy Technology Data Exchange (ETDEWEB)

Tso, Kin [Univ. of California, Berkeley, CA (United States)

1996-05-01

The ¹²⁹Xe-induced reactions on ^natCu, ⁸⁹Y, ¹⁶⁵Ho, and ¹⁹⁷Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the ¹²⁹Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.

Search for entrance channel effects in fusion reactions via neutron evaporation

International Nuclear Information System (INIS)

Ajay Kumar; Kaur, J.; Kumar, A.; Singh, G.; Govil, I.M.; Rakesh Kumar; Datta, S.K.; Chatterjee, M.B.; Yogi, B.K.

2001-01-01

It is generally expected that the compound nuclei formed at the given excitation energies and the angular momenta follow a statistical decay pattern independent of a particular reaction that led to fusion. In order to search the entrance channel effects in the decay of compound nucleus, the reaction 16 O + 64 Zn at oxygen beam energy of 91 MeV and 95 MeV are investigated

Some general features of alpha-particle pick-up reactions

International Nuclear Information System (INIS)

Becchetti, F.D.; Jaenecke, J.

1982-01-01

The general features of single- and multi-α transfer reactions are discussed. While there are numerous difficulties in extracting α-particle ''spectroscopic'' factors, the reduced α-widths extracted appear to be meaningful. These can be related, in an absolute fashion, to α-decay widths (or α-decay lifetimes). Simpler theories describing α-particle transfer reactions are needed and should be formulated in terms of α-widths, i.e. α-particle densities in the nuclear periphery. These are the quantities measured in most experiments. IBA and SU 3 models appear to be most relevant and should be extended to α-transfer reactions for heavy nuclei. (Auth.)

Gravitational Radiation from Post-Newtonian Sources and Inspiralling Compact Binaries

Directory of Open Access Journals (Sweden)

Luc Blanchet

2014-02-01

Full Text Available To be observed and analyzed by the network of gravitational wave detectors on ground (LIGO, VIRGO, etc. and by the future detectors in space (eLISA, etc., inspiralling compact binaries -- binary star systems composed of neutron stars and/or black holes in their late stage of evolution -- require high-accuracy templates predicted by general relativity theory. The gravitational waves emitted by these very relativistic systems can be accurately modelled using a high-order post-Newtonian gravitational wave generation formalism. In this article, we present the current state of the art on post-Newtonian methods as applied to the dynamics and gravitational radiation of general matter sources (including the radiation reaction back onto the source and inspiralling compact binaries. We describe the post-Newtonian equations of motion of compact binaries and the associated Lagrangian and Hamiltonian formalisms, paying attention to the self-field regularizations at work in the calculations. Several notions of innermost circular orbits are discussed. We estimate the accuracy of the post-Newtonian approximation and make a comparison with numerical computations of the gravitational self-force for compact binaries in the small mass ratio limit. The gravitational waveform and energy flux are obtained to high post-Newtonian order and the binary's orbital phase evolution is deduced from an energy balance argument. Some landmark results are given in the case of eccentric compact binaries -- moving on quasi-elliptical orbits with non-negligible eccentricity. The spins of the two black holes play an important role in the definition of the gravitational wave templates. We investigate their imprint on the equations of motion and gravitational wave phasing up to high post-Newtonian order (restricting to spin-orbit effects which are linear in spins, and analyze the post-Newtonian spin precession equations as well as the induced precession of the orbital plane.

Correlation of gravestone decay and air quality 1960-2010

Science.gov (United States)

Mooers, H. D.; Carlson, M. J.; Harrison, R. M.; Inkpen, R. J.; Loeffler, S.

2017-03-01

Evaluation of spatial and temporal variability in surface recession of lead-lettered Carrara marble gravestones provides a quantitative measure of acid flux to the stone surfaces and is closely related to local land use and air quality. Correlation of stone decay, land use, and air quality for the period after 1960 when reliable estimates of atmospheric pollution are available is evaluated. Gravestone decay and SO2 measurements are interpolated spatially using deterministic and geostatistical techniques. A general lack of spatial correlation was identified and therefore a land-use-based technique for correlation of stone decay and air quality is employed. Decadally averaged stone decay is highly correlated with land use averaged spatially over an optimum radius of ≈7 km even though air quality, determined by records from the UK monitoring network, is not highly correlated with gravestone decay. The relationships among stone decay, air-quality, and land use is complicated by the relatively low spatial density of both gravestone decay and air quality data and the fact that air quality data is available only as annual averages and therefore seasonal dependence cannot be evaluated. However, acid deposition calculated from gravestone decay suggests that the deposition efficiency of SO2 has increased appreciably since 1980 indicating an increase in the SO2 oxidation process possibly related to reactions with ammonia.

Experimental validation of decay heat calculation codes and associated nuclear data libraries for fusion energy

International Nuclear Information System (INIS)

Maekawa, Fujio; Wada, Masayuki; Ikeda, Yujiro

2001-01-01

Validity of decay heat calculations for safety designs of fusion reactors was investigated by using decay heat experimental data on thirty-two fusion reactor relevant materials obtained at the 14-MeV neutron source facility of FNS in JAERI. Calculation codes developed in Japan, ACT4 and CINAC version 4, and nuclear data bases such as JENDL/Act-96, FENDL/A-2.0 and Lib90 were used for the calculation. Although several corrections in algorithms for both the calculation codes were needed, it was shown by comparing calculated results with the experimental data that most of activation cross sections and decay data were adequate. In cases of type 316 stainless steel and copper which were important for ITER, prediction accuracy of decay heat within ±10% was confirmed. However, it was pointed out that there were some problems in parts of data such as improper activation cross sections, e,g., the 92 Mo(n, 2n) 91g Mo reaction in FENDL, and lack of activation cross section data, e.g., the 138 Ba(n, 2n) 137m Ba reaction in JENDL. Modifications of cross section data were recommended for 19 reactions in JENDL and FENDL. It was also pointed out that X-ray and conversion electron energies should be included in decay data. (author)

Experimental validation of decay heat calculation codes and associated nuclear data libraries for fusion energy

Energy Technology Data Exchange (ETDEWEB)

Maekawa, Fujio; Wada, Masayuki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-01-01

Validity of decay heat calculations for safety designs of fusion reactors was investigated by using decay heat experimental data on thirty-two fusion reactor relevant materials obtained at the 14-MeV neutron source facility of FNS in JAERI. Calculation codes developed in Japan, ACT4 and CINAC version 4, and nuclear data bases such as JENDL/Act-96, FENDL/A-2.0 and Lib90 were used for the calculation. Although several corrections in algorithms for both the calculation codes were needed, it was shown by comparing calculated results with the experimental data that most of activation cross sections and decay data were adequate. In cases of type 316 stainless steel and copper which were important for ITER, prediction accuracy of decay heat within {+-}10% was confirmed. However, it was pointed out that there were some problems in parts of data such as improper activation cross sections, e,g., the {sup 92}Mo(n, 2n){sup 91g}Mo reaction in FENDL, and lack of activation cross section data, e.g., the {sup 138}Ba(n, 2n){sup 137m}Ba reaction in JENDL. Modifications of cross section data were recommended for 19 reactions in JENDL and FENDL. It was also pointed out that X-ray and conversion electron energies should be included in decay data. (author)

Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

Science.gov (United States)

Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

2017-09-01

We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

Phenomenological study of exclusive binary light particle production from antiproton-proton annihilation at FAIR/PANDA

Science.gov (United States)

Ying, Wang

2016-08-01

Exclusive binary annihilation reactions induced by antiprotons of momentum from 1.5 to 15 GeV/c can be extensively investigated at FAIR/PANDA [1]. We are especially interested in the channel of charged pion pairs. Whereas this very probable channel constitutes the major background for other processes of interest in the PANDA experiment, it carries unique physical information on the quark content of proton, allowing to test different models (quark counting rules, statistical models,..). To study the binary reactions of light meson formation, we are developing an effective Lagrangian model based on Feynman diagrams which takes into account the virtuality of the exchanged particles. Regge factors [2] and form factors are introduced with parameters which may be adjusted on the existing data. We present preliminary results of our formalism for different reactions of light meson production leading to reliable predictions of cross sections, energy and angular dependencies in the PANDA kinematical range.

Binary Masking & Speech Intelligibility

DEFF Research Database (Denmark)

Boldt, Jesper

The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...... binary mask -- is introduced. The target binary mask shows the same substantial increase in intelligibility as the ideal binary mask and is proposed as a new reference for binary masking. In the category of real-life applications, two new methods are proposed: a method for estimation of the ideal binary...

{beta}-Delayed proton-decay study of {sup 20}Mg and its implications for the {sup 19}Ne(p,{gamma}){sup 20}Na breakout reaction in X-ray bursts

Energy Technology Data Exchange (ETDEWEB)

Wallace, J.P., E-mail: J.P.Wallace@sms.ed.ac.uk [University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Woods, P.J.; Lotay, G. [University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); Alharbi, A.; Banu, A. [Cyclotron Institute, Texas A and M University, College Station, TX (United States); David, H.M.; Davinson, T. [University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); McCleskey, M.; Roeder, B.T.; Simmons, E.; Spiridon, A.; Trache, L.; Tribble, R.E. [Cyclotron Institute, Texas A and M University, College Station, TX (United States)

2012-05-30

Under astrophysical conditions of high temperature and density, such as for example found in X-ray bursts, breakout can occur from the hot CNO cycles into the rapid proton capture process. A key breakout route is via the sequence {sup 15}O({alpha},{gamma}){sup 19}Ne(p,{gamma}){sup 20}Na. The {sup 19}Ne(p,{gamma}){sup 20}Na reaction rate is expected to be dominated by a single resonance at 457(3) keV. The identity of the resonance has been under discussion for a long time, with J{sup {pi}}=1{sup +} and 3{sup +} assignments suggested. In this study of the {beta}-delayed proton decay of {sup 20}Mg we report a new, significantly more stringent, upper limit on the {beta}-decay branch to this state of 0.02% with a confidence level of 90%. This makes a 1{sup +} assignment highly unlikely and favours a 3{sup +} assignment for which no branch is expected to be observed. The 3{sup +} state is predicted to have a significantly higher resonance strength, and to produce a proportionately higher {sup 19}Ne(p,{gamma}){sup 20}Na reaction rate in X-ray burst conditions.

Dynamics of {sup 40,48}Ca+{sup 238}U→{sup 278,286}112{sup ⁎} reactions across the Coulomb barrier using dynamical cluster decay model

Energy Technology Data Exchange (ETDEWEB)

Sandhu, Kirandeep; Kaur, Gurvinder; Sharma, Manoj K., E-mail: msharma@thapar.edu

2014-01-15

The role of deformations and related orientations (optimum or compact) is investigated in reference to dynamics of {sup 40,48}Ca+{sup 238}U→{sup 278,286}112{sup ⁎} reactions using dynamical cluster decay model (DCM). The use of quadrupole and hexadecapole deformations in the decay of compound system suggest that the degree of compactness changes with addition of higher order deformations. The decay cross-sections are calculated in reference to the available data, including β{sub 2}-static deformations within ‘optimum’ orientation approach. The comparative analysis of spherical, β{sub 2}-static and dynamic alongwith β{sub 4}-static deformations is investigated at comparable center of mass energy of 230 MeV for both nuclei. To address the specific role of optimized orientations in the decay of {sup 278}112{sup ⁎} and {sup 286}112{sup ⁎} nuclei, the calculations are done using equatorial compact and polar elongated orientations. Using hot equatorial collisions, symmetric fission is observed as the dominant decay mode across the barrier, which otherwise becomes asymmetric for cold elongated approach. The calculated cross-sections match nicely with experimental data using hot configuration but the same are overestimated for the use of cold (polar) orientation approach at deep sub-barrier region. This overestimation in the deep sub-barrier region may be associated with the quasi-fission decay channel. The contribution of QF in both {sup 278}112{sup ⁎} and {sup 286}112{sup ⁎} nuclei are predicted through the overestimated cross-sections being more for neutron-deficient {sup 278}112{sup ⁎} nucleus, in agreement with experimental results. Larger barrier modification ΔV{sub B} is observed at sub-barrier energies for both isotopes of Z=112 nucleus. Also the contribution of ΔV{sub B} at lower incident energies is relatively higher for cold elongated polar configuration as compared to hot compact equatorial configuration, causing overestimation of cross

Interacting binary stars

CERN Document Server

Sahade, Jorge; Ter Haar, D

1978-01-01

Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

Δ decay in nuclei: recent results and perspectives

International Nuclear Information System (INIS)

Ramstein, B.; Tarle-Rousteau, S.; Hennino, T.; Jourdain, J.C.; Roy-Stephan, M.; Zupranki, P.; Boyard, J.L.; Morsch, H.P.; Radvanyi, P.; Sams, T.; Spang, W.; Zupraski, P.; Gosset, J.; Lemaire, M.C.; Lhote, D.; Osterlund, M.; Zupranski, P.

1996-01-01

We present data on the decay of the Δ resonance excited in 1 H, 2 H, 4 He, 12 C and 208 Pb by the (3He, t) reaction at 2 GeV incident energy. The quasi-free decay of the Δ resonance and the absorption process are investigated. In addition, we find indication for a coherent process where a pion is emitted and the target nucleus is left in its ground state. This process will be studied with the dedicated set-up Spes4π. The first data with this new detection have just been taken. (author)

New Decay Studies of 66Ga

Science.gov (United States)

Kumar, Suresh; Ahmad, I.; Carpenter, M. P.; Chen, J.; Greene, J. P.; Kondev, F. G.; Zhu, S.

2014-03-01

High-energy γ rays with energies up to 5.0 MeV are emitted in the radioactive decay of 66Ga (T1/2 = 9.49 h). Thus, this radionuclide appears to be a suitable candidate for energy and efficiency calibrations of high-resolution, γ-ray spectrometers that are employed in studies of very neutron-rich nuclei which have large Qβ values. In addition, accurate emission probabilities of this isotope are of interest to medical imaging applications, owing to the existence of large β+ decay branches, which need to be characterized with better accuracy. Decay studies of 66Ga were initiated using the γ-ray spectroscopy technique. The source was produced by means of the 66Zn(p,n) reaction at a beam energy of 12 MeV. Singles and γ - γ coincidences measurements were carried out using a single Ge detector and Gammasphere, respectively. The previously known 66Ga decay scheme was extended and many new γ rays were placed in the daughter nuclide 66Zn. The work at ANL was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. S. Kumar acknowledges support from the Indo-US Science and Technology Forum for the award of a Research Fellowship.

Anomalous decay and scattering processes of the η meson

International Nuclear Information System (INIS)

Kubis, Bastian; Plenter, Judith

2015-01-01

We amend a recent dispersive analysis of the anomalous η decay process η → π + π - γ by the effects of the a2 tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η' decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward.backward asymmetry, for the crossed process γπ - → π - η, which could be measured in Primakoff reactions in the future. (orig.)

Decay of 36K

International Nuclear Information System (INIS)

Fritts, M.J.

1976-01-01

36 K was produced via the 36 Ar(p, n) 36 K reaction. Measurement of 27 β + delayed γ rays associated with the decay of 36 K implied 10 new β + branches to energy levels in 36 Ar. Branching ratios and logft values are calculated for the β + branches. Restrictions on spin and parity assignments for the 36 Ar levels are given, as well as branching ratios for γ transitions from these levels. The half-life of 36 K is determined to be 344 +- 3 msec

Excitation of the isomeric states 1h sub 1 sub 1 sub / sub 2 in the nuclear reactions with gamma-quanta, neutrons and at beta decay

CERN Document Server

Belov, A G; Melnikova, L M; Ponomarev, V Yu; Tsoneva, N; Stoyanov, C; Balabanov, N P; Tonchev, A P

2001-01-01

The isomeric ratios (IR) were measured in the isotones with N = 81 ( sup 1 sup 3 sup 5 Xe, sup 1 sup 3 sup 7 Ba, sup 1 sup 3 sup 9 Ce, sup 1 sup 4 sup 1 Nd, and sup 1 sup 4 sup 3 Sm). Isomers with J suppi 11/2 sup - were excited in the reactions (n, gamma), (gamma, n), and beta sup + decay of sup 1 sup 3 sup 9 Pr and sup 1 sup 4 sup 1 Pm. The activation methods of gamma-spectrum measurement of reaction products was used. The marked difference of IR was observed in the isotones with the different atomic numbers Z but in the same reactions. The calculations of IR using low-level spectrum of final nuclei and probability of radiation transitions on the base of the quasiparticle phonon model were performed. The satisfactory agreement of the measured and calculated IR was obtained for all studied isotopes. The dependence of IR on Z is explained by the different energy of reaction and different probability levels population of the activation

ϕ-meson photoproduction on hydrogen in the neutral decay mode

Science.gov (United States)

Seraydaryan, H.; Amaryan, M. J.; Gavalian, G.; Baghdasaryan, H.; Weinstein, L.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

2014-05-01

We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp →pϕ(KSKL). The experiment was performed with a tagged photon beam of energy 1.6≤Eγ≤3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp →pKSX to be KL. The presented results significantly enlarge the existing data on ϕ photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of ϕ photoproduction.

Full Ionisation In Binary-Binary Encounters With Small Positive Energies

Science.gov (United States)

Sweatman, W. L.

2006-08-01

Interactions between binary stars and single stars and binary stars and other binary stars play a key role in the dynamics of a dense stellar system. Energy can be transferred between the internal dynamics of a binary and the larger scale dynamics of the interacting objects. Binaries can be destroyed and created by the interaction. In a binary-binary encounter, full ionisation occurs when both of the binary stars are destroyed in the interaction to create four single stars. This is only possible when the total energy of the system is positive. For very small energies the probability of this occurring is very low and it tends towards zero as the total energy tends towards zero. Here the case is considered for which all the stars have equal masses. An asymptotic power law is predicted relating the probability of full ionisation with the total energy when this latter quantity is small. The exponent, which is approximately 2.31, is compared with the results from numerical scattering experiments. The theoretical approach taken is similar to one used previously in the three-body problem. It makes use of the fact that the most dramatic changes in scale and energies of a few-body system occur when its components pass near to a central configuration. The position, and number, of these configurations is not known for the general four-body problem, however, with equal masses there are known to be exactly five different cases. Separate consideration and comparison of the properties of orbits close to each of these five central configurations enables the prediction of the form of the cross-section for full ionisation for the case of small positive total energy. This is the relation between total energy and the probability of total ionisation described above.

N* and {delta}* decays into N{pi}{sup 0}{pi}{sup 0}

Energy Technology Data Exchange (ETDEWEB)

Thoma, U. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); II. Physikalisches Institut, Universitaet Giessen (Germany); Fuchs, M. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Anisovich, A.V. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Anton, G. [Physikalisches Institut, Universitaet Erlangen (Germany); Bantes, R. [Physikalisches Institut, Universitaet Bonn (Germany); Bartholomy, O.; Beck, R. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Beloglazov, Yu. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Crede, V. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Department of Physics, Florida State University (United States); Ehmanns, A.; Ernst, J.; Fabry, I. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Flemming, H. [Physikalisches Institut, Universitaet Bochum (Germany); Foesel, A. [Physikalisches Institut, Universitaet Erlangen (Germany); Funke, Chr. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Gothe, R. [Physikalisches Institut, Universitaet Bonn (Germany); Gridnev, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Gutz, E. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany); Hoeffgen, St. [Physikalisches Institut, Universitaet Bonn (Germany); Horn, I. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn (Germany)] (and others)

2008-01-17

Decays of baryon resonances in the second and the third resonance region into N{pi}{sup 0}{pi}{sup 0} are studied by photoproduction of two neutral pions off protons. Partial decay widths of N* and {delta}* resonances decaying into {delta}(1232){pi}, N({pi}{pi}){sub S}, N(1440)P{sub 11}{pi}, and N(1520)D{sub 13}{pi} are determined in a partial wave analysis of this data and of data from other reactions. Several partial decay widths were not known before. Interesting decay patterns are observed which are not even qualitatively reproduced by quark model calculations. In the second resonance region, decays into {delta}(1232){pi} dominate clearly. The N({pi}{pi}){sub S}-wave provides a significant contribution to the cross section, especially in the third resonance region. The P{sub 13}(1720) properties found here are at clear variance to PDG values.

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

2013-11-10

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

International Nuclear Information System (INIS)

Kaltenegger, Lisa; Haghighipour, Nader

2013-01-01

We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886

Synthesis and characterization of type solid solution in the binary ...

Indian Academy of Sciences (India)

We have investigated Bi2O3–Eu2O3 binary system by doping with Eu2O3 in the composition range from 1 to 10 mole% via solid state reactions and succeeded to stabilize -Bi2O3 ... Our experimental observations strongly suggested that oxygen deficiency type non-stoichiometry is present in doped type solid solutions.

Polarity Correspondence: A General Principle for Performance of Speeded Binary Classification Tasks

Science.gov (United States)

Proctor, Robert W.; Cho, Yang Seok

2006-01-01

Differences in performance with various stimulus-response mappings are among the most prevalent findings for binary choice reaction tasks. The authors show that perceptual or conceptual similarity is not necessary to obtain mapping effects; a type of structural similarity is sufficient. Specifically, stimulus and response alternatives are coded as…

Searching for Rapid Orbital Decay of WASP-18b

Energy Technology Data Exchange (ETDEWEB)

Wilkins, Ashlee N.; Deming, Drake; Hamilton, Douglas [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Delrez, Laetitia [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Barker, Adrian J. [Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom); Gillon, Michael; Jehin, Emmanuel, E-mail: awilkins@astro.umd.edu [Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, allée du 6 Août 19C, B-4000 Lige (Belgium)

2017-02-20

The WASP-18 system, with its massive and extremely close-in planet, WASP-18b ( M{sub p} = 10.3 M{sub J}, a = 0.02 au, P = 22.6 hr), is one of the best-known exoplanet laboratories to directly measure Q ′, the modified tidal quality factor and proxy for efficiency of tidal dissipation, of the host star. Previous analysis predicted a rapid orbital decay of the planet toward its host star that should be measurable on the timescale of a few years, if the star is as dissipative as is inferred from the circularization of close-in solar-type binary stars. We have compiled published transit and secondary eclipse timing (as observed by WASP, TRAPPIST, and Spitzer ) with more recent unpublished light curves (as observed by TRAPPIST and Hubble Space Telescope ) with coverage spanning nine years. We find no signature of a rapid decay. We conclude that the absence of rapid orbital decay most likely derives from Q ′ being larger than was inferred from solar-type stars and find that Q ′ ≥ 1 × 10{sup 6}, at 95% confidence; this supports previous work suggesting that F stars, with their convective cores and thin convective envelopes, are significantly less tidally dissipative than solar-type stars, with radiative cores and large convective envelopes.

Coordination conversion of cobalt(II) in binary aqueous-organic solvents

Energy Technology Data Exchange (ETDEWEB)

Khvostova, N.O.; Karapetyan, G.O.; Yanush, O.V.

1985-11-01

It has been shown that the thermochromic conversions of cobalt(II) in binary solvents are influenced by a number of factors: the nature of the solvent, the strength of the complexes of octahedral symmetry formed, the outer-sphere influence of the solvent on the complexes, the form of the anion, the solvation of the participants in the reaction, and the interaction of the components of the solvent with one another. A correlation between the strength and the spectral position of the absorption bands of the complexes of the activator has been established, and a spectroscopic criterion for selecting the solvents has been proposed. The expediency of using binary solvents to create effective thermochromic media with variable phototransmission has been substantiated.

First observation and branching fraction and decay parameter measurements of the weak radiative decay $\\Xi^0 \\to \\Lambda e^{+}e^{-}$

CERN Document Server

Batley, J Richard; Lazzeroni, C; Munday, D J; Patel, M; Slater, M W; Wotton, S A; Arcidiacono, R; Bocquet, G; Ceccucci, A; Cundy, Donald C; Doble, N; Falaleev, V; Gatignon, L; Gonidec, A; Grafstrm, P; Kubischta, Werner; Mikulec, I; Norton, A; Panzer-Steindel, B; Rubin, P; Wahl, H; Goudzovski, E; Khristov, P Z; Kekelidze, V D; Litov, L; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Stoynev, S; Zinchenko, A I; Monnier, E; Swallow, E; Winston, R; Sacco, R; Walker, A; Baldini, W; Dalpiaz, P; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Scarpa, M; Bizzeti, A; Calvetti, M; Collazuol, G; Iacopini, E; Lenti, M; Veltri, M; Ruggiero, G; Behler, M; Eppard, K; Eppard, M; Hirstius, A; Kleinknecht, K; Koch, U; Marouelli, P; Masetti, L; Moosbrugger, U; Morales-Morales, C; Peters, A; Wanke, R; Winhart, A; Dabrowski, A; Fonseca-Martin, T; Velasco, M; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Lamanna, G; Lubrano, P; Michetti, A; Nappi, A; Pepé, M; Valdata, M; Petrucci, M C; Piccini, M; Cerri, C; Costantini, F; Fantechi, R; Fiorini, L; Giudici, S; Mannelli, I; Pierazzini, G M; Sozzi, M; Cheshkov, C; Chèze, J B; De Beer, M; Debu, P; Gouge, G; Marel, Gérard; Mazzucato, E; Peyaud, B; Vallage, B; Holder, M; Maier, A; Ziolkowski, M; Biino, C; Cartiglia, N; Clemencic, M; Goy-Lopez, S; Marchetto, F; Menichetti, E; Pastrone, N; Wislicki, W; Dibon, Heinz; Jeitler, Manfred; Markytan, Manfred; Neuhofer, G; Widhalm, L

2007-01-01

The weak radiative decay $Xi^0 -> \\Lambda e^+ e^- $ has been detected for the first time. We find 412 candidates in the signal region, with an estimated background of $15pm 5$ events. We determine the branching fraction ${cal{B}}(\\Xi^0 -> \\Lambda e^+ e^- ) = [7.6pm 0.4({m stat})pm 0.4({m syst})pm 0.2({m norm})] imes 10^{-6}$, consistent with an internal bremsstrahlung process, and the decay asymmetry parameter $\\alpha_{\\Xi \\Lambda ee} = -0.8pm 0.2$, consistent with that of $\\Xi^0 -> \\Lambda \\gamma$. The charge conjugate reaction $\\overline{\\Xi^{0}} -> \\overline{\\Lambda} e^+ e^- $ has also been observed.

Interacting binaries

CERN Document Server

Shore, S N; van den Heuvel, EPJ

1994-01-01

This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

The Trojan Horse method for nuclear astrophysics: Recent results for direct reactions

International Nuclear Information System (INIS)

Tumino, A.; Gulino, M.; Spitaleri, C.; Cherubini, S.; Romano, S.; Cognata, M. La; Pizzone, R. G.; Rapisarda, G. G.; Lamia, L.

2014-01-01

The Trojan Horse method is a powerful indirect technique to determine the astrophysical factor for binary rearrangement processes A+x→b+B at astrophysical energies by measuring the cross section for the Trojan Horse (TH) reaction A+a→B+b+s in quasi free kinematics. The Trojan Horse Method has been successfully applied to many reactions of astrophysical interest, both direct and resonant. In this paper, we will focus on direct sub-processes. The theory of the THM for direct binary reactions will be shortly presented based on a few-body approach that takes into account the off-energy-shell effects and initial and final state interactions. Examples of recent results will be presented to demonstrate how THM works experimentally

The Trojan Horse method for nuclear astrophysics: Recent results for direct reactions

Energy Technology Data Exchange (ETDEWEB)

Tumino, A.; Gulino, M. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy and Università degli Studi di Enna Kore, Enna (Italy); Spitaleri, C.; Cherubini, S.; Romano, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania, Italy and Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Cognata, M. La; Pizzone, R. G.; Rapisarda, G. G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Lamia, L. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy)

2014-05-09

The Trojan Horse method is a powerful indirect technique to determine the astrophysical factor for binary rearrangement processes A+x→b+B at astrophysical energies by measuring the cross section for the Trojan Horse (TH) reaction A+a→B+b+s in quasi free kinematics. The Trojan Horse Method has been successfully applied to many reactions of astrophysical interest, both direct and resonant. In this paper, we will focus on direct sub-processes. The theory of the THM for direct binary reactions will be shortly presented based on a few-body approach that takes into account the off-energy-shell effects and initial and final state interactions. Examples of recent results will be presented to demonstrate how THM works experimentally.

η decays at Saclay

International Nuclear Information System (INIS)

Mayer, B.

1991-01-01

A facility dedicated to the production of η mesons has been installed at the Saturne synchrotron with the purpose of investigating rare decays of this meson. The η are produced by the pd → 3 Heη reaction near threshold and tagged by the detection of 3 He in a magnetic spectrometer (SPES2). A rate of 10 5 /s tagged η can be achieved. In the first experiment, η → μ + μ - , the μ will be detected in range telescopes. Magnetic spectrometers for lepton detection are considered for future experiments

Study of 193Os beta- decay

International Nuclear Information System (INIS)

Zahn, Guilherme Soares

2006-01-01

In this work, the excited levels of 193 Ir populated by the beta - decay of 193 Os (T 1/2 ∼ 30h) were investigated. For that purpose, ∼ 5 mg samples of 99%-enriched 192 Os were irradiated under a thermal neutron flux of ∼ 10 12 s -1 and then analysed both using single gamma spectroscopy and a 4-detector multi parametric acquisition facility, which provided data for both a gamma gamma coincidence analysis and a directional angular correlation gamma gamma (θ ) study. From these data, 28 transitions were added to this decay scheme, 11 of which were previously known from nuclear reactions and 17 observed for the first time. Eight excited levels were also added to the decay scheme, 3 of which were known from nuclear reaction studies - the remaining 5 are suggested for the first time. Moreover, it was possible to confirm suspicions found in reference that the levels at 848.93 keV and 849.093 keV are indeed the same; it was also possible to confirm the existence of an excited level at 806.9 keV, which had been inferred, but not experimentally confirmed in beta decay studies to date. The angular correlation analysis allowed for the definition of the spin of the excited level at 874 keV as 5/2 +; moreover, the results showed a 79% probability that the spin of the 1078 keV level is 5/2/'-, and also restricted the spin possibilities for the new excited level at 960 keV to two values (1/2 or 3/2). It was also possible to measure the multipolarity mixing ratio (δ Ln+1 /L n ) for 43 transitions - 19 of them for the first time and most of the others with a better precision than previously known. Finally, an attempt was made to understand the low-lying levels structure for this nucleus using a theoretical model, which reproduced the ground state and the two lowest-lying excited levels in 193 Ir. (author)

Study of the decay scheme of 159Tm

International Nuclear Information System (INIS)

Aguer, Pierre; Bastin, Genevieve; Chin Fan Liang; Libert, Jean; Paris, Pierre; Peghaire, Alain

1975-01-01

The energy levels of 159 Er have been investigated from the decay of 159 Tm (T(1/2)=9mn). Samples were obtained by (p,xn) reaction and on-line separation through Isocele facility. A level scheme is proposed with 24 levels between 0 and 1.3MeV [fr

A massive pulsar in a compact relativistic binary.

Science.gov (United States)

Antoniadis, John; Freire, Paulo C C; Wex, Norbert; Tauris, Thomas M; Lynch, Ryan S; van Kerkwijk, Marten H; Kramer, Michael; Bassa, Cees; Dhillon, Vik S; Driebe, Thomas; Hessels, Jason W T; Kaspi, Victoria M; Kondratiev, Vladislav I; Langer, Norbert; Marsh, Thomas R; McLaughlin, Maura A; Pennucci, Timothy T; Ransom, Scott M; Stairs, Ingrid H; van Leeuwen, Joeri; Verbiest, Joris P W; Whelan, David G

2013-04-26

Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 ± 0.04 solar mass (M⊙) pulsar in a 2.46-hour orbit with a 0.172 ± 0.003 M⊙ white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

Thermodynamics and kinetics insight into reaction mechanism of Cu{sub 2}ZnSnSe{sub 4} nanoink based on binary metal-amine complexes in polyetheramine-synthesized process

Energy Technology Data Exchange (ETDEWEB)

Wang, Chi-Jie [Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Shei, Shih-Chang, E-mail: scshei@mail.nutn.edu.tw [Department of Electrical Engineering, National University of Tainan, 700, Taiwan, ROC (China); Chang, Shoou-Jinn [Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

2016-08-15

This paper reports on the reaction mechanism of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) nanoink via a solvent-thermal reflux method using copper (Cu), zinc (Zn), tin (Sn), and selenium (Se) powders as precursors and polyetheramine as a reaction solvent. The formation of CZTSe nanoparticles in polyetheramine began with the formation of binary phase CuSe and CuSe{sub 2} due to the strong catalysis provided by polyetheramine. Finally, ternary crystals of Cu{sub 2}SnSe{sub 3} transformed into well-dispersed nanocrystals of Cu{sub 2}ZnSnSe{sub 4}. The size of the crystals was shown to decrease with reaction time due to the emulsification effect of the polyetheramine epoxy group. The PH value-reaction time curves for single Cu, Zn elements and CZTSe from all participants elements reacted together have a relationship just reversed each other and both multistage feature were observed, which indicates that the CZTSe reaction was dominated by copper and zinc elements. The PH-temperature mechanism demonstrates that the reaction was controlled by the formation of metal-amine complexes, especially, after heating the PH-time variation manner is the same for pure element and all four elements reacted together. To the best of our knowledge, this is the first study on the mechanism underlying CZTSe formation based on the reactivity and stability of reaction species. - Highlights: • Reaction mechanism of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) nanoink via a solvent-thermal reflux method using polyetheramine was developed. • PH effect on thermal dynamics and characteristics of reagents and solvents in the CZTSe nanoink has been realized. • PH-temperature mechanism demonstrates that the reaction controlled by the formation of metal-amine complexes.

Eclipsing binaries in open clusters

DEFF Research Database (Denmark)

Southworth, John; Clausen, J.V.

2006-01-01

Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

Decay properties of nuclei close to Z = 108 and N = 162

Energy Technology Data Exchange (ETDEWEB)

Dvorak, Jan

2007-07-12

The goal of the research conducted in the frame of this thesis was to investigate the decay properties of the nuclides {sup 269-271}Hs and their daughters using an improved chemical separation and detection system. Shell stabilization was predicted in the region around Z=108 and N=162 in calculations, taking into account possible higher orders of deformations of the nuclei. The nucleus {sup 270}Hs with a closed proton and a closed neutron deformed shell, was predicted to be ''deformed doubly magic''. Nuclei around {sup 270}Hs can be produced only via fusion reactions at picobarn levels, resulting in a production rates of few atoms per day. Investigating short-lived nuclei using rapid chemical separation and subsequent on-line detection methods provides an independent and alternative means to electromagnetic on-line separators. Chemical separation of Hs in the form of HsO{sub 4} provides an excellent tool to study the formation reactions and nuclear structure in this region of the chart of nuclides due to a high overall efficiency and a very high purification factor. The goal was accomplished, as element 108, hassium, was produced in the reaction {sup 248}Cm({sup 26}Mg,xn){sup 274-x}Hs and chemically isolated. After gas phase separation of HsO{sub 4}, 26 genetically linked decay chains have been observed. These were attributed to decays of three different Hs isotopes produced in the 3-5n evaporation channels. The known decay chain of {sup 269}Hs, the 5n evaporation product, serves as an anchor point, thus allowing the unambiguous assignment of the observed decay chains to the 5n, 4n, and 3n channels, respectively. Decay properties of five nuclei have been unambiguously established for the first time, including the one for the the doubly-magic nuclide {sup 270}Hs. This hassium isotope is the next doubly magic nucleus after the well known {sup 208}Pb and the first experimentally observed even-even nucleus on the predicted N=162 neutron shell. The

The decay scheme of 229Ra

International Nuclear Information System (INIS)

Yang, W.F.; Yuan, S.G.; Fang, K.M.; Shen, S.F.; Mou, W.T.; Zhang, X.Q.; Li, Z.Q.

1997-01-01

By bombarding the natural thorium targets with 14 MeV neutrons, 229 Ra was produced through the reaction 232 Th(n,α) 229 Ra. The radium activities were separated from the irradiated targets by coprecipitation with the BaCl 2 . A total of 18 new weak γ rays with energies of 14.5, 15.6, 18.8, 21.8, 22.5, 44.0, 47.5, 55.0, 63.0, 69.6, 93.6, 94.1, 98.5, 102.2, 104.5, 106.1, 161.1, and 171.5 keV which could be assigned to the decay of 229 Ra were observed in the isolated radium fractions employing high resolution HPGe detectors and γ(X)-γ coincidence methods. A decay scheme of 229 Ra based on these observations is proposed. (orig.). With 2 figs

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

International Nuclear Information System (INIS)

Haghighipour, Nader; Kaltenegger, Lisa

2013-01-01

We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results

CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

Energy Technology Data Exchange (ETDEWEB)

Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

2013-11-10

We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

Anomalous decay and scattering processes of the η meson

Energy Technology Data Exchange (ETDEWEB)

Kubis, Bastian, E-mail: kubis@hiskp.uni-bonn.de [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn (Germany); Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn (Germany); Plenter, Judith [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn (Germany)

2015-06-25

We amend a recent dispersive analysis of the anomalous η decay process η→π{sup +}π{sup -}γ by the effects of the a{sub 2} tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η{sup ′} decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon’s anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward–backward asymmetry, for the crossed process γπ{sup -}→π{sup -}η, which could be measured in Primakoff reactions in the future.

Anomalous decay and scattering processes of the η meson

Energy Technology Data Exchange (ETDEWEB)

Kubis, Bastian [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Universitaet Bonn, Bethe Center for Theoretical Physics, Bonn (Germany); Plenter, Judith [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

2015-06-15

We amend a recent dispersive analysis of the anomalous η decay process η → π{sup +}π{sup -}γ by the effects of the a2 tensor meson, the lowest-lying resonance that can contribute in the πη system. While the net effects on the measured decay spectrum are small, they may be more pronounced for the analogous η' decay. There are nonnegligible consequences for the η transition form factor, which is an important quantity for the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment. We predict total and differential cross sections, as well as a marked forward.backward asymmetry, for the crossed process γπ{sup -} → π{sup -}η, which could be measured in Primakoff reactions in the future. (orig.)

Organic alloy systems suitable for the investigation of regular binary and ternary eutectic growth

Science.gov (United States)

Sturz, L.; Witusiewicz, V. T.; Hecht, U.; Rex, S.

2004-09-01

Transparent organic alloys showing a plastic crystal phase were investigated experimentally using differential scanning calorimetry and directional solidification with respect to find a suitable model system for regular ternary eutectic growth. The temperature, enthalpy and entropy of phase transitions have been determined for a number of pure substances. A distinction of substances with and without plastic crystal phases was made from their entropy of melting. Binary phase diagrams were determined for selected plastic crystal alloys with the aim to identify eutectic reactions. Examples for lamellar and rod-like eutectic solidification microstructures in binary systems are given. The system (D)Camphor-Neopentylglycol-Succinonitrile is identified as a system that exhibits, among others, univariant and a nonvariant eutectic reaction. The ternary eutectic alloy close to the nonvariant eutectic composition solidifies with a partially faceted solid-liquid interface. However, by adding a small amount of Amino-Methyl-Propanediol (AMPD), the temperature of the nonvariant eutectic reaction and of the solid state transformation from plastic to crystalline state are shifted such, that regular eutectic growth with three distinct nonfaceted phases is observed in univariant eutectic reaction for the first time. The ternary phase diagram and examples for eutectic microstructures in the ternary and the quaternary eutectic alloy are given.

Towards an understanding of staggering effects in dissipative binary collisions

International Nuclear Information System (INIS)

D'Agostino, M.; Bruno, M.; Gulminelli, F.; Morelli, L.; Baiocco, G.; Bardelli, L.; Barlini, S.; Cannata, F.; Casini, G.; Geraci, E.; Gramegna, F.; Kravchuk, V.L.; Marchi, T.; Moroni, A.; Ordine, A.; Raduta, Ad.R.

2012-01-01

The reactions 32 S+ 58,64 Ni are studied at 14.5 A MeV. Evidence is found for important odd–even effects in isotopic observables of selected peripheral collisions corresponding to the decay of a projectile-like source. The influence of secondary decays on the staggering is studied with a correlation function technique. It is shown that this method is a powerful tool to get experimental information on the evaporation chain, in order to constrain model calculations. Specifically, we show that odd–even effects are due to interplay between pairing effects in the nuclear masses and in the level densities.

Black-hole binaries as relics of gamma-ray burst/hypernova explosions

Science.gov (United States)

Moreno Mendez, Enrique

The Collapsar model, in which a fast-spinning massive star collapses into a Kerr black hole, has become the standard model to explain long-soft gamma-ray bursts and hypernova explosions (GRB/HN). However, stars massive enough (those with ZAMS mass ≳ (18--20) M⊙ ) to produce these events evolve through a path that loses too much angular momentum to produce a central engine capable of delivering the necessary energy. In this work I suggest that the soft X-ray transient sources are the remnants of GRBs/HNe. Binaries in which the massive primary star evolves a carbon-oxygen burning core, then start to transfer material to the secondary star (Case C mass transfer), causing the orbit to decay until a common-envelope phase sets in. The secondary spirals in, further narrowing the orbit of the binary and removing the hydrogen envelope of the primary star. Eventually the primary star becomes tidally locked and spins up, acquiring enough rotational energy to power up a GRB/HN explosion. The central engine producing the GRB/HN event is the Kerr black hole acting through the Blandford-Znajek mechanism. This model can explain not only the long-soft GRBs, but also the subluminous bursts (which comprise ˜ 97% of the total), the long-soft bursts and the short-hard bursts (in a neutron star, black hole merger). Because of our binary evolution through Case C mass transfer, it turns out that for the subluminous and cosmological bursts, the angular momentum O is proportional to m3/2D , where mD is the mass of the donor (secondary star). This binary evolution model has a great advantage over the Woosley Collapsar model; one can "dial" the donor mass in order to obtain whatever angular momentum is needed to drive the explosion. Population syntheses show that there are enough binaries to account for the progenitors of all known classes of GRBs.

Kinematical coincidence method in transfer reactions

Energy Technology Data Exchange (ETDEWEB)

Acosta, L.; Amorini, F. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Auditore, L. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Berceanu, I. [Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cardella, G., E-mail: cardella@ct.infn.it [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Chatterjiee, M.B. [Saha Institute for Nuclear Physics, Kolkata (India); De Filippo, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Francalanza, L.; Gianì, R. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); Grassi, L. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Rudjer Boskovic Institute, Zagreb (Croatia); Grzeszczuk, A. [Institut of Physics, University of Silesia, Katowice (Poland); La Guidara, E. [INFN—Sezione di Catania, Via S. Sofia, 95123 Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lanzalone, G. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Facoltà di Ingegneria e Architettura, Università Kore, Enna (Italy); Lombardo, I. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Scienze Fisiche, Università Federico II and INFN Sezione di Napoli (Italy); Loria, D.; Minniti, T. [INFN Gruppo Collegato di Messina and Dipartimento di Fisica, Università di Messina (Italy); Pagano, E.V. [INFN—Laboratori Nazionali del Sud, Via S. Sofia, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, Catania (Italy); and others

2013-07-01

A new method to extract high resolution angular distributions from kinematical coincidence measurements in binary reactions is presented. Kinematics is used to extract the center of mass angular distribution from the measured energy spectrum of light particles. Results obtained in the case of {sup 10}Be+p→{sup 9}Be+d reaction measured with the CHIMERA detector are shown. An angular resolution of few degrees in the center of mass is obtained. The range of applicability of the method is discussed.

Close binary stars

International Nuclear Information System (INIS)

Larsson-Leander, G.

1979-01-01

Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

Data Evaluation for 56Co ε + β+ Decay

International Nuclear Information System (INIS)

Baglin, Coral M.; MacMahon, T. Desmond

2005-01-01

Recommended values for nuclear and atomic data pertaining to the (var e psilon) + β + decay of 56 Co are provided here, followed by comments on evaluation procedures and a summary of all available experimental data. 56 Co is a radionuclide which is potentially very useful for Ge detector efficiency calibration because it is readily produced via the 56 Fe(p,n) reaction, its half-life of 77.24 days is conveniently long, and it provides a number of relatively strong γ rays with energies up to ∼3500 keV. The transition intensities recommended here for the strongest lines will be included in the forthcoming International Atomic Energy Agency Coordinated Research Programme document ''Update of X- and Gamma-ray Decay Data Standards for Detector Calibration and Other Applications'', and the analysis for all transitions along with relevant atomic data have been provided to the Decay Data Evaluation Project

The G-parity violating decays phi→ππ, phi→etaππ, and phi→πω

International Nuclear Information System (INIS)

Karnakov, V.A.

1985-01-01

G-forbidden hadronic decays of the phi meson into the ππ, etaππ, and πω states are studied. Special attention is paid to the amplitude for the transition phi→rho, which plays an important role in these decays. The amplitude of the decay chain phi→ω→rho is analyzed in detail and its contribution to the interference parameter Z/sub π/ of the reaction e + e - →ππ is calculated. The relative probabilities B(phi→etaππ) = 0.35 x 10 -6 and B(phi→πω) = 0.82 x 10 -4 and the interference curves in the reactions e + e - →etaππ and e + e - →πω are calculated. The angular distributions are given

π0 decay branching ratios of 5ΛHe and 12ΛC hypernuclei

International Nuclear Information System (INIS)

Okada, S.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.C.; Fukuda, T.; Hashimoto, O.; Hwang, J.I.; Kameoka, S.; Kang, B.H.; Kim, E.H.; Kim, J.H.; Kim, M.J.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S.N.; Noumi, H.; Okayasu, Y.; Outa, H.; Park, H.; Saha, P.K.; Sato, Y.; Sekimoto, M.; Takahashi, T.; Tamura, H.; Tanida, K.; Toyoda, A.; Tsukada, K.; Watanabe, T.; Yim, H.J.

2005-01-01

We precisely measured π0 branching ratios of 5 Λ He and 12 Λ C hypernuclei produced via the (π+,K+) reaction. Using these π0 branching ratios with the π- branching ratios and lifetimes, we obtained the π0 decay widths and the non-mesonic weak decay widths with an accuracy of ∼5% (stat) for both hypernuclei

Massive Black Hole Binary Evolution

Directory of Open Access Journals (Sweden)

Merritt David

2005-11-01

Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

Dynamical decay of nuclei at high temperature: competition between particle emission and fission decay

International Nuclear Information System (INIS)

Delagrange, H.; Gregoire, C.; Scheuter, F.; Abe, Y.

1985-06-01

A generalized diffusion equation is propounded to follow the time evolution of an excited nucleus towards fission including along the particle decay. This theoretical model is built in order to try to analyse the anomalous behaviour of particle emission observed in many experimental data for heavy-ion induced reactions. Some calculations for the systems 194 Hg, 170 Yb and 248 Cf are presented. A possible extension of this generalized formalism is suggested to deal more consistently with the experimental data. 52 refs. 10 figs.

Computer code for double beta decay QRPA based calculations

Energy Technology Data Exchange (ETDEWEB)

Barbero, C. A.; Mariano, A. [Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina and Instituto de Física La Plata, CONICET, La Plata (Argentina); Krmpotić, F. [Instituto de Física La Plata, CONICET, La Plata, Argentina and Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo (Brazil); Samana, A. R.; Ferreira, V. dos Santos [Departamento de Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, BA (Brazil); Bertulani, C. A. [Department of Physics, Texas A and M University-Commerce, Commerce, TX (United States)

2014-11-11

The computer code developed by our group some years ago for the evaluation of nuclear matrix elements, within the QRPA and PQRPA nuclear structure models, involved in neutrino-nucleus reactions, muon capture and β{sup ±} processes, is extended to include also the nuclear double beta decay.

A random walk in the land of precompound decay

International Nuclear Information System (INIS)

Akkermans, J.M.

1982-09-01

Several aspects of precompound-decay (preequilibrium) reactions, relevant for the application to fusion-reactor design, are considered. Preequilibrium angular distributions are discussed in the framework of the generalized exciton model. A critical discussion of the theory is given and various refinements are suggested. A comparison is made with experimental data on 14 MeV neutron-induced reactions for a large number of nuclides covering the whole mass range. The exciton model is further generalized to the description of multiparticle emission. Preequilibrium effects in multiple emission are investigated. Computational aspects of preequilibrium theory are examined whereby the exact solution for the mean exciton-state lifetimes is derived in closed form. A random-walk model of precompound decay is developed. The dynamics of the nuclear relaxation process and the fluctuations originating from its stochastic nature are studied in detail. Uncertainty calculations are presented for the exciton-state lifetimes and the emission cross-sections. (Auth.)

Isovector excitations in 100Nb and their decays by neutron emission studied via the Mo100(t,He3+n reaction at 115 MeV/u

Directory of Open Access Journals (Sweden)

K. Miki

2017-06-01

Full Text Available Spin–isospin excitations in Nb100 were studied via the Mo100(t,He3 charge-exchange reaction at 115 MeV/u with the goal to constrain theoretical models used to describe the isovector spin response of nuclei. The experiment was performed with a secondary beam of tritons, and 3He particles were analyzed in the S800 magnetic spectrometer. Decay by neutron emission from excited states in Nb100 was observed by using plastic and liquid scintillator arrays. Differential cross sections were analyzed and monopole excitations were revealed by using a multipole decomposition analysis. The Gamow–Teller transition strength observed at low excitation energies, which is important for estimating the electron-capture rate in astrophysical scenarios, was strongly fragmented and reduced compared to single-particle and spherical mean-field models. The consideration of deformation in the theoretical estimates was found to be important to better describe the fragmentation and strengths. A strong excitation of the isovector spin giant monopole resonance was observed, and well reproduced by the mean-field models. Its presence makes the extraction of Gamow–Teller strengths at high excitation energies difficult. The branches for statistical and direct decay by neutron emission were identified in the spectra. The upper limit for the branching ratio by direct decay (integrated over all observed excitations was determined to be 20±6%. Even though the statistical uncertainties in the neutron-coincident data were too large to perform detailed studies of the decay by neutron emission from individual states and resonances, the experiment demonstrates the feasibility of the method.

Kilonova/Macronova Emission from Compact Binary Mergers

Directory of Open Access Journals (Sweden)

Masaomi Tanaka

2016-01-01

Full Text Available We review current understanding of kilonova/macronova emission from compact binary mergers (mergers of two neutron stars or a neutron star and a black hole. Kilonova/macronova is emission powered by radioactive decays of r-process nuclei and it is one of the most promising electromagnetic counterparts of gravitational wave sources. Emission from the dynamical ejecta of ~0.01M⊙ is likely to have a luminosity of ~1040–1041 erg s−1 with a characteristic timescale of about 1 week. The spectral peak is located in red optical or near-infrared wavelengths. A subsequent accretion disk wind may provide an additional luminosity or an earlier/bluer emission if it is not absorbed by the precedent dynamical ejecta. The detection of near-infrared excess in short GRB 130603B and possible optical excess in GRB 060614 supports the concept of the kilonova/macronova scenario. At 200 Mpc distance, a typical peak brightness of kilonova/macronova with 0.01M⊙ ejecta is about 22 mag and the emission rapidly fades to >24 mag within ~10 days. Kilonova/macronova candidates can be distinguished from supernovae by (1 the faster time evolution, (2 fainter absolute magnitudes, and (3 redder colors. Since the high expansion velocity (v~0.1–0.2c is a robust outcome of compact binary mergers, the detection of smooth spectra will be the smoking gun to conclusively identify the gravitational wave source.

Gravitational waves from remnant massive neutron stars of binary neutron star merger: Viscous hydrodynamics effects

Science.gov (United States)

Shibata, Masaru; Kiuchi, Kenta

2017-06-01

Employing a simplified version of the Israel-Stewart formalism of general-relativistic shear-viscous hydrodynamics, we explore the evolution of a remnant massive neutron star of binary neutron star merger and pay special attention to the resulting gravitational waveforms. We find that for the plausible values of the so-called viscous alpha parameter of the order 10-2 the degree of the differential rotation in the remnant massive neutron star is significantly reduced in the viscous time scale, ≲5 ms . Associated with this, the degree of nonaxisymmetric deformation is also reduced quickly, and as a consequence, the amplitude of quasiperiodic gravitational waves emitted also decays in the viscous time scale. Our results indicate that for modeling the evolution of the merger remnants of binary neutron stars we would have to take into account magnetohydrodynamics effects, which in nature could provide the viscous effects.

Monte Carlo simulation of fission yields, kinetic energy, fission neutron spectrum and decay γ-ray spectrum for 232Th(n,f) reaction induced by 3H(d,n) 4He neutron source

International Nuclear Information System (INIS)

Zheng Wei; Zeen Yao; Changlin Lan; Yan Yan; Yunjian Shi; Siqi Yan; Jie Wang; Junrun Wang; Jingen Chen; Chinese Academy of Sciences, Shanghai

2015-01-01

Monte Carlo transport code Geant4 has been successfully utilised to study of neutron-induced fission reaction for 232 Th in the transport neutrons generated from 3 H(d,n) 4 He neutron source. The purpose of this work is to examine the applicability of Monte Carlo simulations for the computation of fission reaction process. For this, Monte Carlo simulates and calculates the characteristics of fission reaction process of 232 Th(n,f), such as the fission yields distribution, kinetic energy distribution, fission neutron spectrum and decay γ-ray spectrum. This is the first time to simulate the process of neutron-induced fission reaction using Geant4 code. Typical computational results of neutron-induced fission reaction of 232 Th(n,f) reaction are presented. The computational results are compared with the previous experimental data and evaluated nuclear data to confirm the certain physical process model in Geant4 of scientific rationality. (author)

Concentration fluctuations in non-isothermal reaction-diffusion systems. II. The nonlinear case

NARCIS (Netherlands)

Bedeaux, D.; Ortiz de Zárate, J.M.; Pagonabarraga, I.; Sengers, J.V.; Kjelstrup, S.

2011-01-01

In this paper, we consider a simple reaction-diffusion system, namely, a binary fluid mixture with an association-dissociation reaction between two species. We study fluctuations at hydrodynamic spatiotemporal scales when this mixture is driven out of equilibrium by the presence of a temperature

THE VERY SHORT PERIOD M DWARF BINARY SDSS J001641-000925

Energy Technology Data Exchange (ETDEWEB)

Davenport, James R. A.; Becker, Andrew C.; Hawley, Suzanne L.; Gunning, Heather C.; Munshi, Ferah A.; Albright, Meagan [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); West, Andrew A. [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Bochanski, John J. [Astronomy and Astrophysics Department, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Holtzman, Jon [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 88003 (United States); Hilton, Eric J., E-mail: jrad@astro.washington.edu [Department of Geology and Geophysics and Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

2013-02-10

We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641-000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M {sub 1} = 0.54 {+-} 0.07 M {sub Sun} and M {sub 2} = 0.34 {+-} 0.04 M {sub Sun }, and radii of R {sub 1} = 0.68 {+-} 0.03 R {sub Sun} and R {sub 2} = 0.58 {+-} 0.03 R {sub Sun }, respectively. This solution places both components above the critical Roche overfill limit, providing strong evidence that SDSS J001641-000925 is the first verified M-dwarf contact binary system. Within the follow-up spectroscopy we find signatures of non-solid body rotation velocities, which we interpret as evidence for mass transfer or loss within the system. In addition, our photometry samples the system over nine years, and we find strong evidence for period decay at the rate of P-dot {approx} 8 s yr{sup -1}. Both of these signatures raise the intriguing possibility that the system is in over-contact, and actively losing angular momentum, likely through mass loss. This places SDSS J001641-000925 as not just the first M-dwarf over-contact binary, but one of the few systems of any spectral type known to be actively undergoing coalescence. Further study of SDSS J001641-000925 is ongoing to verify the nature of the system, which may prove to be a unique astrophysical laboratory.

Partial Accretion in the Propeller Stage of Low-mass X-Ray Binary Aql X–1

International Nuclear Information System (INIS)

Güngör, C.; Ekşi, K. Y.; Göğüş, E.; Güver, T.

2017-01-01

Aql X–1 is one of the most prolific low-mass X-ray binary transients (LMXBTs) showing outbursts almost annually. We present the results of our spectral analyses of Rossi X-Ray Timing Explorer /proportional counter-array observations of the 2000 and 2011 outbursts. We investigate the spectral changes related to the changing disk-magnetosphere interaction modes of Aql X–1. The X-ray light curves of the outbursts of LMXBTs typically show phases of fast rise and exponential decay. The decay phase shows a “knee” where the flux goes from the slow-decay to the rapid-decay stage. We assume that the rapid decay corresponds to a weak propeller stage at which a fraction of the inflowing matter in the disk accretes onto the star. We introduce a novel method for inferring, from the light curve, the fraction of the inflowing matter in the disk that accretes onto the neutron star depending on the fastness parameter. We determine the fastness parameter range within which the transition from the accretion to the partial propeller stage is realized. This fastness parameter range is a measure of the scale height of the disk in units of the inner disk radius. We applied the method to a sample of outbursts of Aql X–1 with different maximum flux and duration times. We show that different outbursts with different maximum luminosity and duration follow a similar path in the parameter space of accreted/inflowing mass flux fraction versus fastness parameter.

Partial Accretion in the Propeller Stage of Low-mass X-Ray Binary Aql X–1

Energy Technology Data Exchange (ETDEWEB)

Güngör, C.; Ekşi, K. Y. [İstanbul Technical University, Faculty of Science and Letters, Physics Engineering Department, 34469, İstanbul (Turkey); Göğüş, E. [Sabancı University, Faculty of Engineering and Natural Science, Orhanlı—Tuzla, 34956, İstanbul (Turkey); Güver, T., E-mail: gungorcan@itu.edu.tr [İstanbul University, Science Faculty, Department of Astronomy and Space Sciences, Beyazıt, 34119, İstanbul (Turkey)

2017-10-10

Aql X–1 is one of the most prolific low-mass X-ray binary transients (LMXBTs) showing outbursts almost annually. We present the results of our spectral analyses of Rossi X-Ray Timing Explorer /proportional counter-array observations of the 2000 and 2011 outbursts. We investigate the spectral changes related to the changing disk-magnetosphere interaction modes of Aql X–1. The X-ray light curves of the outbursts of LMXBTs typically show phases of fast rise and exponential decay. The decay phase shows a “knee” where the flux goes from the slow-decay to the rapid-decay stage. We assume that the rapid decay corresponds to a weak propeller stage at which a fraction of the inflowing matter in the disk accretes onto the star. We introduce a novel method for inferring, from the light curve, the fraction of the inflowing matter in the disk that accretes onto the neutron star depending on the fastness parameter. We determine the fastness parameter range within which the transition from the accretion to the partial propeller stage is realized. This fastness parameter range is a measure of the scale height of the disk in units of the inner disk radius. We applied the method to a sample of outbursts of Aql X–1 with different maximum flux and duration times. We show that different outbursts with different maximum luminosity and duration follow a similar path in the parameter space of accreted/inflowing mass flux fraction versus fastness parameter.

Massive Binary Black Holes in the Cosmic Landscape

Science.gov (United States)

Colpi, Monica; Dotti, Massimo

2011-02-01

Binary black holes occupy a special place in our quest for understanding the evolution of galaxies along cosmic history. If massive black holes grow at the center of (pre-)galactic structures that experience a sequence of merger episodes, then dual black holes form as inescapable outcome of galaxy assembly, and can in principle be detected as powerful dual quasars. But, if the black holes reach coalescence, during their inspiral inside the galaxy remnant, then they become the loudest sources of gravitational waves ever in the universe. The Laser Interferometer Space Antenna is being developed to reveal these waves that carry information on the mass and spin of these binary black holes out to very large look-back times. Nature seems to provide a pathway for the formation of these exotic binaries, and a number of key questions need to be addressed: How do massive black holes pair in a merger? Depending on the properties of the underlying galaxies, do black holes always form a close Keplerian binary? If a binary forms, does hardening proceed down to the domain controlled by gravitational wave back reaction? What is the role played by gas and/or stars in braking the black holes, and on which timescale does coalescence occur? Can the black holes accrete on flight and shine during their pathway to coalescence? After outlining key observational facts on dual/binary black holes, we review the progress made in tracing their dynamics in the habitat of a gas-rich merger down to the smallest scales ever probed with the help of powerful numerical simulations. N-Body/hydrodynamical codes have proven to be vital tools for studying their evolution, and progress in this field is expected to grow rapidly in the effort to describe, in full realism, the physics of stars and gas around the black holes, starting from the cosmological large scale of a merger. If detected in the new window provided by the upcoming gravitational wave experiments, binary black holes will provide a deep view

Tritium decay helium-3 effects in tungsten

Directory of Open Access Journals (Sweden)

M. Shimada

2017-08-01

Full Text Available Tritium (T implanted by plasmas diffuses into bulk material, especially rapidly at elevated temperatures, and becomes trapped in neutron radiation-induced defects in materials that act as trapping sites for the tritium. The trapped tritium atoms will decay to produce helium-3 (3He atoms at a half-life of 12.3 years. 3He has a large cross section for absorbing thermal neutrons, which after absorbing a neutron produces hydrogen (H and tritium ions with a combined kinetic energy of 0.76 MeV through the 3He(n,HT nuclear reaction. The purpose of this paper is to quantify the 3He produced in tungsten by tritium decay compared to the neutron-induced helium-4 (4He produced in tungsten. This is important given the fact that helium in materials not only creates microstructural damage in the bulk of the material but alters surface morphology of the material effecting plasma-surface interaction process (e.g. material evolution, erosion and tritium behavior of plasma-facing component materials. Effects of tritium decay 3He in tungsten are investigated here with a simple model that predicts quantity of 3He produced in a fusion DEMO FW based on a neutron energy spectrum found in literature. This study reveals that: (1 helium-3 concentration was equilibrated to ∼6% of initial/trapped tritium concentration, (2 tritium concentration remained approximately constant (94% of initial tritium concentration, and (3 displacement damage from 3He(n,HT nuclear reaction became >1 dpa/year in DEMO FW.

Production and decay properties of the delta (970) meson

International Nuclear Information System (INIS)

Gay, J.B.; Chaloupka, V.; Gavillet, Ph.; Hemingway, R.J.; Marzano, F.; Montanet, L.; Blokzijl, R.; Jongejans, B.; Massaro, G.G.G.; Heinen, P.M.; Metzger, W.J.; Timmermans, J.J.M.

1976-01-01

Using an 80 events per microbarn sample of K - p interactions at 4.2 GeV/c the production and decay properties of the delta(970) have been investigated in the following reactions: K - p→Σ + (1385)etaπ - and K - p→Σ + (1385)K 0 K - . (Auth.)

Distribution in flowing reaction-diffusion systems

KAUST Repository

Kamimura, Atsushi; Herrmann, Hans J.; Ito, Nobuyasu

2009-01-01

A power-law distribution is found in the density profile of reacting systems A+B→C+D and 2A→2C under a flow in two and three dimensions. Different densities of reactants A and B are fixed at both ends. For the reaction A+B, the concentration of reactants asymptotically decay in space as x-1/2 and x-3/4 in two dimensions and three dimensions, respectively. For 2A, it decays as log (x) /x in two dimensions. The decay of A+B is explained considering the effect of segregation of reactants in the isotropic case. The decay for 2A is explained by the marginal behavior of two-dimensional diffusion. A logarithmic divergence of the diffusion constant with system size is found in two dimensions. © 2009 The American Physical Society.

Distribution in flowing reaction-diffusion systems

KAUST Repository

Kamimura, Atsushi

2009-12-28

A power-law distribution is found in the density profile of reacting systems A+B→C+D and 2A→2C under a flow in two and three dimensions. Different densities of reactants A and B are fixed at both ends. For the reaction A+B, the concentration of reactants asymptotically decay in space as x-1/2 and x-3/4 in two dimensions and three dimensions, respectively. For 2A, it decays as log (x) /x in two dimensions. The decay of A+B is explained considering the effect of segregation of reactants in the isotropic case. The decay for 2A is explained by the marginal behavior of two-dimensional diffusion. A logarithmic divergence of the diffusion constant with system size is found in two dimensions. © 2009 The American Physical Society.

Study of sup 1 sup 9 sup 4 Tl sup g decay

CERN Document Server

Sudarshan, K; Tripathi, R; Goswami, A; Tomar, B S; Reddy, A V R

2003-01-01

Absolute gamma ray intensities in the decay of sup 1 sup 9 sup 4 Tl sup g have been measured following the radiochemical separation of sup 1 sup 9 sup 4 Pb produced in the reaction of sup 1 sup 9 F + sup 1 sup 8 sup 1 Ta. The (EC+beta sup +) branching ratios in the decay of sup 1 sup 9 sup 4 Tl sup g to various levels of sup 1 sup 9 sup 4 Hg were deduced. Three new levels are introduced in the decay scheme. A precise value of half life of sup 1 sup 9 sup 4 Pb (10.0+-0.4 min) is reported.

Neutron decay, semileptonic hyperon decay and the Cabibbo model

International Nuclear Information System (INIS)

Siebert, H.W.

1989-01-01

The decay rates and formfactor ratios of neutron decay and semileptonic hyperon decays are compared in the framework of the Cabibbo model. The results indicate SU(3) symmetry breaking. The Kobayashi-Maskawa matrix element V us determined from these decays is in good agreement with the value determined from K→πeν decays, and with unitarity of the KM-matrix. (orig.)

Dynamic aspects of the nuclear decay: from the fission to the multifragmentation

International Nuclear Information System (INIS)

Gruyer, Diego

2014-01-01

In this work we study the evolution and nature of reaction and decay mechanisms of hot nuclei produced in heavy ion collisions from E = 8 to 25 MeV/A measured with INDRA. In central Xe+Sn collisions from E = 8 to 25 MeV/A, three-fragment events present a significant cross section without the underlying production mechanism being clearly established. We have shown that fragments arise from two successive binary splittings. The time interval between these two splittings decreases with increasing incident energy, becoming compatible with a simultaneous three-body break-up above E = 20 MeV/A, which was interpreted as the signature of the onset of multifragmentation. Then we have investigated the nature of the multifragmentation process. A statistical analysis of the largest fragment charge (Zmax) distribution produced in central Xe+Sn collisions at E = 25-50 MeV/A allowed us to establish that multifragmentation is a dynamical aggregation process. It also demonstrates the effects of collective radial expansion on multifragmentation partitions through the link between the timescale of the process and the shape of the Zmax distribution. The comparison of fragmentation patterns of comparable size systems produced in symmetric (Xe+Sn) and asymmetric (Ta+Zn) central collisions, which are supposed to follow different trajectories in the nuclear phase diagram, confirm the link between collective radial expansion and fragment partitions in multifragmentation. (author) [fr

Population and particle decay of isobaric analog states in medium heavy nuclei

International Nuclear Information System (INIS)

Gales, S.

1980-05-01

The systematic features of proton stripping and neutron pick-up reactions to Isobaric Analog States in medium heavy nuclei are presented. The ( 3 He,d) reaction investigated at high incident energy is shown to selectively excite high-spin particle-analog states. Similarly the ( 3 He,α) reaction populates hole-analog states. The recent results related to such highly excited states in a wide range of nuclei ( 48 Ca to 208 Pb) are discussed in the framework of the DWBA theory of direct reactions with special emphasis on the treatment of unbound proton states or deeply-bound neutron hole states. The particle decay of Isobaric Analog States are investigated using the ( 3 He,d p) and ( 3 He, α p) sequential processes. The experimental method developed at Orsay (0 0 detection) for particle-particle angular correlations is presented. The advantage and the limits of such approach are illustrated by typical examples of particle decays: core-excited states, neutron particle-hole multiplets and the first observation of the proton emission of hole-analog levels. In conclusion new experimental approaches such as asymmetry measurements for analog states observed in transfer reactions or possible population of double analog states in heavy nuclei are discussed

Analysis of the reaction γp → K{sup 0}Σ{sup +} by the identification of the charged K* decay channel at the BGO-OD experiment using kinematic fitting

Energy Technology Data Exchange (ETDEWEB)

Reitz, Bjoern-Eric [Physikalisches Institut Bonn (Germany); Collaboration: BGO-OD-Collaboration

2016-07-01

The BGO-OD experiment at the ELSA facility in Bonn is built to investigate nucleon excitations via meson photoproduction. A program of measurements of reactions of associated strangeness in the final state has begun, one of which is γp → K{sup 0}Σ{sup +}. One research objective is associated production of strange particles. An interesting reaction channel is γp → K{sup 0}Σ{sup +}. This talk shows the preliminary results of the analysis for the charged decay channel K{sup 0}Σ{sup +} → π{sup -}π{sup +}π{sup 0}p. Due to the small production cross section kinematic fitting has been used to discriminate the wanted channel against background.

Experimental study of precisely selected evaporation chains in the decay of excited 25Mg

Science.gov (United States)

Camaiani, A.; Casini, G.; Morelli, L.; Barlini, S.; Piantelli, S.; Baiocco, G.; Bini, M.; Bruno, M.; Buccola, A.; Cinausero, M.; Cicerchia, M.; D'Agostino, M.; Degelier, M.; Fabris, D.; Frosin, C.; Gramegna, F.; Gulminelli, F.; Mantovani, G.; Marchi, T.; Olmi, A.; Ottanelli, P.; Pasquali, G.; Pastore, G.; Valdré, S.; Verde, G.

2018-04-01

The reaction 12C+13C at 95 MeV bombarding energy is studied using the Garfield + Ring Counter apparatus located at the INFN Laboratori Nazionali di Legnaro. In this paper we want to investigate the de-excitation of 25Mg aiming both at a new stringent test of the statistical description of nuclear decay and a direct comparison with the decay of the system 24Mg formed through 12C+12C reactions previously studied. Thanks to the large acceptance of the detector and to its good fragment identification capabilities, we could apply stringent selections on fusion-evaporation events, requiring their completeness in charge. The main decay features of the evaporation residues and of the emitted light particles are overall well described by a pure statistical model; however, as for the case of the previously studied 24Mg, we observed some deviations in the branching ratios, in particular for those chains involving only the evaporation of α particles. From this point of view the behavior of the 24Mg and 25Mg decay cases appear to be rather similar. An attempt to obtain a full mass balance even without neutron detection is also discussed.

Interfacial reactions in intermetallic matrix composites

International Nuclear Information System (INIS)

Cantrell, L.B.; Clevenger, E.M.; Perepezko, J.H.

1993-01-01

The thermal stability of advanced composites is dominated by the behavior of internal interfaces. Analysis of these internal interfaces often involves consideration of at least ternary order phase equilibria. Limited thermodynamic data exists for ternary and higher order systems. However, a combined approach based upon the use of binary data to estimate ternary phase equilibria and experimentally determined reaction pathways is effective in the analysis of interface reactions in composite systems. In blended powder samples, thermal analysis was used to find possible reaction temperatures, while X-ray analysis, EDS, and EPMA of diffusion couples were used to assess interdiffusion reaction pathways. The approach is illustrated by compatibility studies between TiAl and TiSi 2 at 1,100 C, and in-situ reactions between B 4 C and TiAl at 1300 C where multiple reaction sequences have been analyzed to provide guidance for the design of in-situ reaction processing of composites

The fate of close encounters between binary stars and binary supermassive black holes

Science.gov (United States)

Wang, Yi-Han; Leigh, Nathan; Yuan, Ye-Fei; Perna, Rosalba

2018-04-01

The evolution of main-sequence binaries that reside in the Galactic Centre can be heavily influenced by the central supermassive black hole (SMBH). Due to these perturbative effects, the stellar binaries in dense environments are likely to experience mergers, collisions, or ejections through secular and/or non-secular interactions. More direct interactions with the central SMBH are thought to produce hypervelocity stars (HVSs) and tidal disruption events (TDEs). In this paper, we use N-body simulations to study the dynamics of stellar binaries orbiting a central SMBH primary with an outer SMBH secondary orbiting this inner triple. The effects of the secondary SMBH on the event rates of HVSs, TDEs, and stellar mergers are investigated, as a function of the SMBH-SMBH binary mass ratio. Our numerical experiments reveal that, relative to the isolated SMBH case, the TDE and HVS rates are enhanced for, respectively, the smallest and largest mass ratio SMBH-SMBH binaries. This suggests that the observed event rates of TDEs and HVSs have the potential to serve as a diagnostic of the mass ratio of a central SMBH-SMBH binary. The presence of a secondary SMBH also allows for the creation of hypervelocity binaries. Observations of these systems could thus constrain the presence of a secondary SMBH in the Galactic Centre.

Solving a binary puzzle

NARCIS (Netherlands)

Utomo, P.H.; Makarim, R.H.

2017-01-01

A Binary puzzle is a Sudoku-like puzzle with values in each cell taken from the set {0,1} {0,1}. Let n≥4 be an even integer, a solved binary puzzle is an n×n binary array that satisfies the following conditions: (1) no three consecutive ones and no three consecutive zeros in each row and each

$\\beta$-decay half-life of $^{70}$Kr a bridge nuclide for the rp-process beyond A = 70

CERN Document Server

Oinonen, M; Jokinen, A; Baumann, P; Didierjean, François; Huck, A; Knipper, A; Ramdhane, M; Walter, G; Van Duppen, P; Huyse, M; Marguier, G; Novikov, Yu N; Popov, A; Seliverstov, D M; Schatz, H

2000-01-01

The $\\beta$-decay half-life of $^{70}$Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated $^{70}$Kr ions were produced by 1 GeV proton induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of $^{68}$Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 10$^{6}$g/cm$^{3}$.

Third post-Newtonian dynamics of compact binaries: equations of motion in the centre-of-mass frame

CERN Document Server

Blanchet, L

2003-01-01

The equations of motion of compact binary systems and their associated Lagrangian formulation have been derived in previous works at the third post-Newtonian (3PN) approximation of general relativity in harmonic coordinates. In the present work, we investigate the binary's relative dynamics in the centre-of-mass frame (centre of mass located at the origin of the coordinates). We obtain the 3PN-accurate expressions of the centre-of-mass positions and equations of the relative binary motion. We show that the equations derive from a Lagrangian (neglecting the radiation reaction), from which we deduce the conserved centre-of-mass energy and angular momentum at the 3PN order. The harmonic-coordinates centre-of-mass Lagrangian is equivalent, via a contact transformation of the particles' variables, to the centre-of-mass Hamiltonian in ADM coordinates that is known from the post-Newtonian ADM-Hamiltonian formalism. As an application we investigate the dynamical stability of circular binary orbits at the 3PN order.

Photonuclear reactions in the GNASH code: Benchmarking model calculations for reactions on lead up to 140 MeV

International Nuclear Information System (INIS)

Chadwick, M.B.; Young, P.G.

1994-08-01

The authors have developed the GNASH code to include photonuclear reactions for incident energies up to 140 MeV. Photoabsorption is modeled through the giant resonance at the lower energies, and the quasideuteron mechanism at the higher energies, and the angular momentum coupling of the incident photon to the target is properly accounted for. After the initial interaction, primary and multiple preequilibrium emission of fast particles can occur before compound nucleus decay from the equilibrated compound nucleus. The angular distributions from compound nucleus decay are taken as isotropic, and those from preequilibrium emission (which they obtain from a phase-space model which conserves momentum) are forward-peaked. To test the new modeling they apply the code to calculate photonuclear reactions on 208 Pb for incident energies up to 140 MeV

The Jeans Condition and Collapsing Molecular Cloud Cores: Filaments or Binaries?

International Nuclear Information System (INIS)

Boss, Alan P.; Fisher, Robert T.; Klein, Richard I.; McKee, Christopher F.

2000-01-01

The 1997 and 1998 studies by Truelove and colleagues introduced the Jeans condition as a necessary condition for avoiding artificial fragmentation during protostellar collapse calculations. They found that when the Jeans condition was properly satisfied with their adaptive mesh refinement (AMR) code, an isothermal cloud with an initial Gaussian density profile collapsed to form a thin filament rather than the binary or quadruple protostar systems found in previous calculations. Using a completely different self-gravitational hydrodynamics code introduced by Boss and Myhill in 1992 (B and M), we present here calculations that reproduce the filamentary solution first obtained by Truelove et al. in 1997. The filamentary solution only emerged with very high spatial resolution with the B and M code, with effectively 12,500 radial grid points (R12500). Reproducing the filamentary collapse solution appears to be an excellent means for testing the reliability of self-gravitational hydrodynamics codes, whether grid-based or particle-based. We then show that in the more physically realistic case of an identical initial cloud with nonisothermal heating (calculated in the Eddington approximation with code B and M), thermal retardation of the collapse permits the Gaussian cloud to fragment into a binary protostar system at the same maximum density where the isothermal collapse yields a thin filament. However, the binary clumps soon thereafter evolve into a central clump surrounded by spiral arms containing two more clumps. A roughly similar evolution is obtained using the AMR code with a barotropic equation of state--formation of a transient binary, followed by decay of the binary to form a central object surrounded by spiral arms, though in this case the spiral arms do not form clumps. When the same barotropic equation of state is used with the B and M code, the agreement with the initial phases of the AMR calculation is quite good, showing that these two codes yield mutually

Weak decays of doubly heavy baryons. Multi-body decay channels

Energy Technology Data Exchange (ETDEWEB)

Shi, Yu-Ji; Wang, Wei; Xing, Ye; Xu, Ji [Shanghai Jiao Tong University, INPAC, Shanghai Key Laboratory for Particle Physics and Cosmology, MOE Key Laboratory for Particle Physics, Astrophysics and Cosmology, School of Physics and Astronomy, Shanghai (China)

2018-01-15

The newly-discovered Ξ{sub cc}{sup ++} decays into the Λ{sub c}{sup +}K{sup -}π{sup +}π{sup +}, but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons Ξ{sub cc}, Ω{sub cc}, Ξ{sub bc}, Ω{sub bc}, Ξ{sub bb} and Ω{sub bb}, in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future. (orig.)

Pre-equilibrium particle decay in the photonuclear reactions

International Nuclear Information System (INIS)

Wu, J.R.; Chang, C.C.

1976-11-01

Calculations of particle energy spectra resulting from the photonuclear reactions at energies below the meson production threshold have been carried out in the framework of combining the pre-equilibrium exiton model and the quasi-deuteron model. A 2p-2h initial state in the exciton model is assumed because in the energy region above giant resonance the quasi-deuteron absorption is the dominant process. With these combined models, the subsequent secondary interactions of the emerging particle with the rest of the nucleus following the initial photon-nucleus interaction are appropriately taken into account. The experimental difference energy spectra of fast photoneutrons from several elements (Al, Cu, In, Sn, Ta, Pb, Bi and U) at bremsstrahlung energies of 55 and 85 MeV and the photoproton energy spectra from 12 C at bremsstrahlung energy 110 MeV were compared with the theoretical predictions. General agreements in both spectral shapes and cross sections are obtained. The relative yields of the reactions (γ, xn) resulting from monoenergetic photons on 127 I at 50, 100 and 150 MeV are also predicted reasonably well by the combined models together with the conventional evaporation theory

Entrance channel influence on the formation and decay of hot nuclei

International Nuclear Information System (INIS)

Harar, S.

1987-04-01

Different entrance channels have been investigated to form very hot nuclei and to study their decay properties. i) Argon and Nickel projectiles accelerated around the Fermi energy show that central collisions induce momentum transfers to target nuclei which are proportional to the mass of the projectile and not to its velocities in the studied energy range. The preequilibrium model fits nicely the experimental results. The decay properties of the fission products for hot nuclei will be presented. Both head-on collisions and peripheral massive transfers contribute to the formation of very excited nuclei. The question of the influence of the energy deposit in the composite like system in limiting their yields is discussed. ii) Investigations have been also achieved with alpha projectiles at much higher incident energy (around 1 GeV/u). It is shown that hot and thermalized nuclei are also formed even when the nucleon-nucleon collisions are predominant. A sensitive parameter of the transition from binary fission to multifragmentation seems to be the energy deposit in the target residues rather than the projectile velocity

Binary collision rates of relativistic thermal plasmas. I Theoretical framework

Science.gov (United States)

Dermer, C. D.

1985-01-01

Binary collision rates for arbitrary scattering cross sections are derived in the case of a beam of particles interacting with a Maxwell-Boltzmann (MB) plasma, or in the case of two MB plasmas interacting at generally different temperatures. The expressions are valid for all beam energies and plasma temperatures, from the nonrelativistic to the extreme relativistic limits. The calculated quantities include the reaction rate, the energy exchange rate, and the average rate of change of the squared transverse momentum component of a monoenergetic particle beam as a result of scatterings with particles of a MB plasma. Results are specialized to elastic scattering processes, two-temperature reaction rates, or the cold plasma limit, reproducing previous work.

On Uniform Decay of the Entropy for Reaction–Diffusion Systems

KAUST Repository

Mielke, Alexander

2014-09-10

This work provides entropy decay estimates for classes of nonlinear reaction–diffusion systems modeling reversible chemical reactions under the detailed-balance condition. We obtain explicit bounds for the exponential decay of the relative logarithmic entropy, being based essentially on the application of the Log-Sobolev estimate and a convexification argument only, making it quite robust to model variations. An important feature of our analysis is the interaction of the two different dissipative mechanisms: pure diffusion, forcing the system asymptotically to the homogeneous state, and pure reaction, forcing the solution to the (possibly inhomogeneous) chemical equilibrium. Only the interaction of both mechanisms provides the convergence to the homogeneous equilibrium. Moreover, we introduce two generalizations of the main result: (i) vanishing diffusion constants in some chemical components and (ii) usage of different entropy functionals. We provide a few examples to highlight the usability of our approach and shortly discuss possible further applications and open questions.

Revisiting big-bang nucleosynthesis constraints on long-lived decaying particles

Science.gov (United States)

Kawasaki, Masahiro; Kohri, Kazunori; Moroi, Takeo; Takaesu, Yoshitaro

2018-01-01

We study the effects of long-lived massive particles, which decayed during the big-bang nucleosynthesis (BBN) epoch, on the primordial abundance of light elements. Compared to previous studies, (i) the reaction rates of standard BBN reactions are updated, (ii) the most recent observational data on the light element abundance and cosmological parameters are used, (iii) the effects of the interconversion of energetic nucleons at the time of inelastic scattering with background nuclei are considered, and (iv) the effects of the hadronic shower induced by energetic high-energy antinucleons are included. We compare the theoretical predictions on the primordial abundance of light elements with the latest observational constraints, and we derive upper bounds on the relic abundance of the decaying particle as a function of its lifetime. We also apply our analysis to an unstable gravitino, the superpartner of a graviton in supersymmetric theories, and obtain constraints on the reheating temperature after inflation.

Measurement of the branching ratio for η→π0γγ decay

International Nuclear Information System (INIS)

Prakhov, S.; Nefkens, B.M.K.; Clajus, M.; Marusic, A.; McDonald, S.; Phaisangittisakul, N.; Price, J.W.; Starostin, A.; Tippens, W.B.; Allgower, C.E.; Spinka, H.; Bekrenev, V.; Koulbardis, A.; Kozlenko, N.; Kruglov, S.; Lopatin, I.; Briscoe, W.J.; Shafi, A.; Comfort, J.R.; Craig, K.

2005-01-01

The branching ratio (BR) for the rare decay η→π 0 γγ was measured with the Crystal Ball multiphoton spectrometer. The result, BR(η→π 0 γγ)=(3.5±0.7 stat ±0.6 syst )x10 -4 , is in agreement with calculations of chiral perturbation theory to third order. We have used a sample of 28 million η mesons produced at the BNL Alternating Gradient Synchrotron using the π - p→ηn reaction close to threshold. We detail the intricate extraction of the signal, which has about 1.6 thousand η→π 0 γγ events, from the overwhelming background of η→3π 0 decays and from the π - p→π 0 π 0 n reaction

Giant resonances: reaction theory approach

International Nuclear Information System (INIS)

Toledo Piza, A.F.R. de; Foglia, G.A.

1989-09-01

The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt

From nuclear reactions to liquid-drop collisions

International Nuclear Information System (INIS)

Menchaca R, A.; Huidobro, F.; Martinez D, A.; Michaelian, K.; Perez, A.; Rodriguez, V.; Carjan, N.

1997-01-01

A review of the experimental and theoretical situation in coalescence and fragmentation studies of binary liquid-drop collisions is given, putting in perspective our own contributions, which include experiments with mercury and oil drops and the application of a nuclear reaction model, specifically modified by us for the macroscopic case. (Author)

G-parity breaking decays of phi → ππ, phi → etaππ and phi → πω

International Nuclear Information System (INIS)

Karnakov, V.A.

1985-01-01

G-parity forbidden hadronic phi decays into ππ, etaππ, πω states are considered. The main attention is paid to the phi → rho transition amplitude, which is signigicant for studied decays. The successive psi → ω → rho transition amplitude is analysed in detail and the contribution of the transition to the interference parameter Zsub(π) of e + e - → ππ reaction is calculated. The decay widths B(phi → etaππ)=0.35x10 -6 , B(phi → πω)=0.82x10 -4 and the interference curve in e + e - → etaππ and e + e - → πω reactions have been calculated. Angular distributions are given

Studies of the yields of 57Fe(II)-species produced after the EC-decay and of 60Co(II)-species produced in the (n, γ) reaction in cobalt(III) coordination compounds

International Nuclear Information System (INIS)

Sano, Hirotoshi; Harada, Masayuki; Endo, Kazutoyo

1978-01-01

The yields of 57 Fe(II)-species produced after EC-decay were compared with those of 60 Co(II)-species produced in the 59 Co(n, γ) 60 Co reaction for twelve cobalt(III) coordination compounds. The results indicate that the radiochemical yield of 60 Co(II)-species correlates with the yield of 57 Fe(II)-species except in the case of [Co(NH 3 ) 6 ] 2 (CrO 4 ) 3 . The anomalously low yield of 57 Fe(II)-species in [Co(NH 3 ) 6 ] 2 (CrO 4 ) 3 is ascribed to the reaction of chromate anions with ammine ligands initiated by the nuclear transformation in a solid. (author)

A study of the decay modes of hot systems formed in the Ar + Au and Ar + Th reactions

International Nuclear Information System (INIS)

Lott, B.; Cramer, B.; Ingold, G.; Jahnke, U.; Schwinn, E.; Doubre, H.; Galin, J.; Guerreau, D.; Jiang, D.X.; Morjean, M.; Piasecki, E.; Pouthas, J.; Sokolov, A.; Gatty, B.; Jacquet, D.

1990-01-01

Decay channels of hot systems formed in Ar + Au and Ar + Th reactions have been investigated by measuring the associated neutron multiplicity with a 4π liquid scintillator detector. The presented results show that, in contrast with the conclusion of the folding angle method, fission remains very probable as a deexcitation channel for hot systems even at 44 MeV/u, but its cross section decreases when the bombarding energy increases from 32 MeV/u to 44 MeV/u. On the opposite, the heavy residue production increases in this incident energy domain. The average IMF multiplicity per central collision is shown to be large, minimum values of 1.0 and 1.2 have been found for E inc = 44 and 77 MeV/u respectively. The possible link between the previously observed saturation in the thermal energy deposited in the system and the increasing probability for this system to avoid fissioning for increasing bombarding energies is discussed. A possible explanation could be found in an important non equilibrium emission of light particles or IMFs

Weak decays

International Nuclear Information System (INIS)

Wojcicki, S.

1978-11-01

Lectures are given on weak decays from a phenomenological point of view, emphasizing new results and ideas and the relation of recent results to the new standard theoretical model. The general framework within which the weak decay is viewed and relevant fundamental questions, weak decays of noncharmed hadrons, decays of muons and the tau, and the decays of charmed particles are covered. Limitation is made to the discussion of those topics that either have received recent experimental attention or are relevant to the new physics. (JFP) 178 references

Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

Directory of Open Access Journals (Sweden)

Gholam Hossein Rounaghi

2011-09-01

Full Text Available The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°c and DS°c for formation of (p-isopropyl-calix[6]arene·Cs+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

Preequilibrium decay models and the quantum Green function method

International Nuclear Information System (INIS)

Zhivopistsev, F.A.; Rzhevskij, E.S.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Teoreticheskoj i Ehksperimental'noj Fiziki)

1977-01-01

The nuclear process mechanism and preequilibrium decay involving complex particles are expounded on the basis of the Green function formalism without the weak interaction assumptions. The Green function method is generalized to a general nuclear reaction: A+α → B+β+γ+...rho, where A is the target nucleus, α is a complex particle in the initial state, B is the final nucleus, and β, γ, ... rho are nuclear fragments in the final state. The relationship between the generalized Green function and Ssub(fi)-matrix is established. The resultant equations account for: 1) direct and quasi-direct processes responsible for the angular distribution asymmetry of the preequilibrium component; 2) the appearance of addends corresponding to the excitation of complex states of final nucleus; and 3) the relationship between the preequilibrium decay model and the general models of nuclear reaction theories (Lippman-Schwinger formalism). The formulation of preequilibrium emission via the S(T) matrix allows to account for all the differential terms in succession important to an investigation of the angular distribution assymetry of emitted particles

Study of the properties of the superheavy nuclei Z=117 produced in the 249Bk + 48Ca reaction

International Nuclear Information System (INIS)

Oganessian, Y.T.; Abdullin, F.S.; Dmitriev, S.N.; Itkis, M.G.; Polyakov, A.N.; Sagaidak, R.N.; Shirokovsky, I.V.; Shumeiko, M.V.; Subbotin, V.G.; Sukhov, A.M.; Tsyganov, Y.S.; Utyonkov, V.K.; Voinov, A.A.; Vostokin, G.K.; Alexander, C.; Binder, J.; Boll, R.A.; Ezold, J.; Felker, K.; Miernik, K.; Roberto, J.B.; Rykaczewski, K.P.; Gostic, J.M.; Henderson, R.A.; Moody, K.J.; Shaughnessy, D.H.; Stoyer, M.A.; Stoyer, N.J.; Grzywacz, R.K.; Miller, D.; Hamilton, J.H.; Ramayya, A.V.; Ryabinin, M.A.

2014-01-01

The reaction of 249 Bk with 48 Ca have been reinvestigated to provide new evidence for the discovery of element 117 on a larger number of events. The experiments were performed at five projectile energies and with a total beam dose of 48 Ca of about 4.6*10 19 . Two isotopes 293,294 117 were synthesized in the 249 Bk+ 48 Ca reaction, providing excitation functions and α-decay spectra of the produced isotopes that establishes these nuclei to be the products of the 4n- and 3n-evaporation channels, respectively. Decay properties of 293,294 117 and of all the daughter products agree with the data of the experiment in which these nuclei were synthesized for the first time in 2010. The new 289 115 events, populated by a decay of 293 117, demonstrate the same decay properties as those observed for 289 115 produced in the 243 Am( 48 Ca,2n) reaction thus providing cross-bombardment evidence. In addition, a single decay of 294 118 was observed from the reaction with 249 Cf - a result of the in-growth of 249 Cf in the 249 Bk target. (authors)

Ground state properties of new element Z=113 and its alpha decay chain

International Nuclear Information System (INIS)

Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou

2005-01-01

The authors investigate the ground state properties of the new element 278 113 and of the α-decay chain with different models, where the new element Z=113 has been produced at RIKEN in Japan by cold-fusion reaction. The experimental decay energies are reproduced by the deformed relativistic mean-field model, by the Skyrme-Hartree-Fock (SHF) model, and by the macroscopic-microscopic model. Theoretical half-lives also reasonably agree with the data. Calculations further show that prolate deformation is important for the ground states of the nuclei in the α-decay chain of 278 113. The common points and differences among different models are compared and discussed. (author)

Relativistic Binaries in Globular Clusters

Directory of Open Access Journals (Sweden)

Matthew J. Benacquista

2013-03-01

Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

Failure of the statistical hypothesis for compound nucleus decay

International Nuclear Information System (INIS)

Chrien, R.E.

1976-01-01

In the past five years, conclusive evidence has accumulated that channel correlations are important in resonance reactions. Experiments showing the failure of the statistical hypothesis for compound nucleus decay are described. The emphasis is on the radiative neutron capture reaction, where much detailed work has been done. A short summary of the theory of the (n,γ) reaction is presented; it is demonstrated that this reaction is a sensitive probe of the wave functions for highly excited nuclear states. Various experimental techniques using reactor and accelerator-based neutron sources are presented. The experiments have shown that both resonant and non-resonant reactions can show single particle effects where the external part of configuration space is dominant. In the non-resonant case, hard sphere capture is important; on resonances, valence particle motion and the contributions of 1 and 3 quasi-particle doorway states make up a significant fraction of the radiative width

Correlations between reaction product yields as a tool for probing heavy-ion reaction scenarios

International Nuclear Information System (INIS)

Gawlikowicz, W.; Agnihotri, D. K.; Baldwin, S. A.; Schroeder, W. U.; Toke, J.; Charity, R. J.; Sarantites, D. G.; Sobotka, L. G.; Souza, R. T. de; Barczyk, T.; Grotowski, K.; Micek, S.; Planeta, R.; Sosin, Z.

2010-01-01

Experimental multidimensional joint distributions of neutrons and charged reaction products were analyzed for 136 Xe + 209 Bi reactions at E/A=28, 40, and 62 MeV and were found to exhibit several different types of prominent correlation patterns. Some of these correlations have a simple explanation in terms of the system excitation energy and pose little challenge to most statistical decay theories. However, several other types of correlation patterns are difficult to reconcile with some, but not other, possible reaction scenarios. In this respect, correlations between the average atomic numbers of intermediate-mass fragments, on the one hand, and light particle multiplicities, on the other, are notable. This kind of multiparticle correlation provides a useful tool for probing reaction scenarios, which is different from the traditional approach of interpreting inclusive yields of individual reaction products.

Merger of binary neutron stars of unequal mass in full general relativity

International Nuclear Information System (INIS)

Shibata, Masaru; Taniguchi, Keisuke; Uryu-bar, Ko-barji

2003-01-01

We present results of three dimensional numerical simulations of the merger of unequal-mass binary neutron stars in full general relativity. A Γ-law equation of state P=(Γ-1)ρε is adopted, where P, ρ, ε, and Γ are the pressure, rest mass density, specific internal energy, and the adiabatic constant, respectively. We take Γ=2 and the baryon rest-mass ratio Q M to be in the range 0.85-1. The typical grid size is (633,633,317) for (x,y,z). We improve several implementations since the latest work. In the present code, the radiation reaction of gravitational waves is taken into account with a good accuracy. This fact enables us to follow the coalescence all the way from the late inspiral phase through the merger phase for which the transition is triggered by the radiation reaction. It is found that if the total rest mass of the system is more than ∼1.7 times of the maximum allowed rest mass of spherical neutron stars, a black hole is formed after the merger, irrespective of the mass ratios. The gravitational waveforms and outcomes in the merger of unequal-mass binaries are compared with those in equal-mass binaries. It is found that the disk mass around the so formed black holes increases with decreasing rest-mass ratios and decreases with increasing compactness of neutron stars. The merger process and the gravitational waveforms also depend strongly on the rest-mass ratios even for the range Q M =0.85-1

Heavy ion reactions: an experimental vista

International Nuclear Information System (INIS)

Stokstad, R.G.

1977-01-01

Examples of recent experiments in the areas of fusion and deep-inelastic scattering are presented and discussed. Emphasis is placed on the importance of individual nucleons in the fusion process, the effects of high angular momentum, and the understanding of compound nuclear decay. Experiments on deep inelastic scattering are entering a new stage in which important parameters of the reaction mechanism are now open to investigation. Primarily through coincidence measurements, direct information on the angular momentum transferred in a collision and on the time scale of decay is being obtained

Nuclear Forensics and Radiochemistry: Reaction Networks

Energy Technology Data Exchange (ETDEWEB)

Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-22

In the intense neutron flux of a nuclear explosion the production of isotopes may occur through successive neutron induced reactions. The pathway to these isotopes illustrates both the complexity of the problem and the need for high quality nuclear data. The growth and decay of radioactive isotopes can follow a similarly complex network. The Bateman equation will be described and modified to apply to the transmutation of isotopes in a high flux reactor. A alternative model of growth and decay, the GD code, that can be applied to fission products will also be described.

Spectrophotometric determination of rare earths in binary mixtures

International Nuclear Information System (INIS)

Krasnova, A.V.; Shvarev, V.S.

1978-01-01

The possibility was investigated of using the reaction with brompyrogallol red (BPR) (dibrompyrogallosulfophthalein) for analyzing binary mixtures of rare earth metals close in ordinal numbers (La-Y, La-Eu, La-Sm, La-Nd, Nd-Y, Nd-Eu). Heavy REM are masked by nitrile-acetic acid (NAA). The experimental design method was used to determine optimum conditions. The optimizing parameters were the optical density measured with respect to water and the amount of the component bound into the complex. It was found that optimum conditions for the analysis of investigated mixtures differ only in the amount of NAA necessary to mask the heavy element [NAA]/[Sm 3+ ]=4; [NAA]/[Eu 3+ ]=5; [NAA]/Nb 3+ ]=10; [NAA]/[Y 3+ ]=2.5. The optimum acidity and the amount of BPR are always the same: pH 6.5; [BPR]/[La 3+ ]=[BPR]/[Nd 3+ ]=4. The given method for analyzing binary mixtures of lanthanoids surpasses considerably in sensitivity the methods based on intrinsic absorption spectra, while retaining the same reproducibility

Neutron-induced cross sections of actinides via the surrogate-reaction method

Directory of Open Access Journals (Sweden)

Ducasse Q.

2013-12-01

Full Text Available The surrogate-reaction method is an indirect way of determining cross sections for reactions that proceed through a compound nucleus. This technique may enable neutron-induced cross sections to be extracted for short-lived nuclei that otherwise cannot be measured. However, the validity of the surrogate method has to be investigated. In particular, the absence of a compound nucleus formation and the Jπ dependence of the decay probabilities may question the method. In this work we study the reactions 238U(d,p239U, 238U(3He,t238Np, 238U(3He,4He237U as surrogates for neutron-induced reactions on 238U, 237Np and 236U, respectively, for which good quality data exist. The experimental set-up enabled the measurement of fission and gamma-decay probabilities. The first results are hereby presented.

Skewed Binary Search Trees

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Moruz, Gabriel

2006-01-01

It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

REACLIB: A Reaction Rate Library for the Era of Collaborative Science

Science.gov (United States)

Meisel, Zachary

2008-10-01

Thermonuclear reaction rates and weak decay rates are of great importance to modern nuclear astrophysics. They are critical in the study of many topics such as Big Bang Nucleosynthesis, X-ray bursts, Supernovae, and S-process element formation, among others. The Joint Institute for Nuclear Astrophysics (JINA) has been created to increase connectivity amongst nuclear astrophysicists in our modern age of highly collaborative science. Within JINA there has been an effort to create a frequently updated and readily accessible database of thermonuclear reactions and weak decay rates. This database is the REACLIB library, which can be accessed at the web address: http://www.nscl.msu.edu/˜nero/db/. Here I will discuss the JINA REACLIB Project, including a new procedure to fit reaction rates as a function of temperature that takes full advantage of physicality. With these updated reaction rates, astrophysical modelers will no longer have to worry about the adverse effects of using obsolete reaction rate libraries lacking physical behavior.

Observations and numerical studies of gamma-ray emission in colliding-wind binaries

International Nuclear Information System (INIS)

Reitberger, K.

2014-01-01

Massive stars in binary systems have long been regarded as potential sources of high-energy gamma rays. The emission is thought to arise in the region where the stellar winds collide, thereby producing accelerated particles which subsequently emit gamma rays.This scenario is supported by observations with the Fermi Large Area Telescope presented in this thesis. To address the underlying emission mechanisms in a quantitative way, numerical simulations that incorporate hydrodynamics, the acceleration of charged particles as well as the subsequent gamma-ray emission were found to be needed.This thesis presents the analysis of a high-energy gamma-ray source and its identification with the particle-accelerating colliding-wind binary system Eta Carinae. In order to go beyond the present understanding of such objects, this work provides detailed description of a new 3D-hydrodynamical model, which incorporates the line-driven acceleration of the winds, gravity, orbital motion and the radiative cooling of the shocked plasma, as well as the diffusive shock acceleration of charged particles in the wind collision region. In a subsequent step we simulate and study the resulting gamma-ray emission via relativistic bremsstrahlung, anisotropic inverse Compton radiation and neutral pion decay. (author) [de

Ion-molecule reactions in the binary mixture of ethylene oxide and trioxane, 1

International Nuclear Information System (INIS)

Kumakura, Minoru; Sugiura, Toshio.

1977-01-01

The formation mechanism of protonated molecular ions by cross-reactions in ethylene oxide-trioxane mixtures has been studied with use of a modified time-of-flight mass spectrometer. The precursors of the product ions were determined by analysis of the fine structure of their ionization efficiency curves using deuterated ethylene oxide. Protonated ethylene oxide is formed by the hydrogen atom transfer reaction of ethylene oxide molecular ion with trioxane, and protonated trioxane by the proton transfer reaction of CHO + (from ethylene oxide) with trioxane. In the ion-molecule reactions of ethylene-d 4 oxide-trioxane mixtures, appreciable isotope effect was observed. The CHO + from ethylene oxide is an important reactant ion as compared with that from trioxane in the proton transfer reaction, and CHO + from ethylene oxide was suggested as a thermal reactive ion. The order of proton affinity could be estimated from the proton transfer reactions involving CHO + . It was found that the proton affinity of trioxane is smaller than that of ethylene oxide. (auth.)

Searching for multifragmentation in light asymmetric systems 93Nb+24Mg and 93Nb+27Al at 30 A.MeV

International Nuclear Information System (INIS)

Manduci, Loredana

2004-01-01

The present work analyses the inverse kinematics reactions 93 Nb+ 27 Al and 93 Nb+ 24 Mg at 30 A.MeV. The reaction events are sorted as a function of the violence of the collision and experimental sources are reconstructed. Their decay is studied by two statistical model simulations: Gemini, for binary sequential decay and SMM for prompt multifragmentation. Both models show a reasonable agreement with the experimental observables starting from a backtracking simulated source decay which has charge and excitation energy distributions comparable to the experimental ones. This result was expected because we are still under the multifragmentation onset. However both models disagree in the fragments production rate. This states the question on the different starting point for the fragment decay probability widths calculations altogether to the idea that taking into account the nuclear dynamics between the saddle-point and the scission point would improve our results. (author) [fr

Binary optics: Trends and limitations

Science.gov (United States)

Farn, Michael W.; Veldkamp, Wilfrid B.

1993-01-01

We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

Decay and fission of the oriented nuclei

CERN Document Server

Kadmenskij, S G

2002-01-01

The fragment angular distributions for binary decay of oriented spherical and deformed nuclei with taking into account the correct transformational properties of wave functions under time inversion have been investigated. It has been shown that for description of fragment angular distributions the adiabatic approximation for collective rotational nuclear degrees of freedom is not correct. It has been demonstrated that this approximation is valid for description of spontaneous and induced low-energy nuclear fission. The dependence of partial fission widths on the orientation of the internal axes spins, projections of spins, and relative angular moments of fission fragments has been analyzed. It has been shown that the adiabatic approximation results in coherent interference of wave functions of fragments relative movement. This interference forms fragments the universal angular distributions of fission fragments for oriented nuclei. For these distributions the deviations from A. Bohr's formula have been invest...

The beta-decay of 48Mn: improved data on Gamow-Teller quenching

International Nuclear Information System (INIS)

Szerypo, J.; Bazin, D.; Brown, B.A.

1991-01-01

Beta-decay studies of very proton-rich nuclides allow to investigate the phenomenon of quenching of Gamow-Teller transitions. A presentation of the experimental techniques is followed by the discussion of preliminray results of the measurements in comparison to shell-model calculations. A corresponding reinvestigation is discussed. A mass-separated 48 Mn beam was used from 12 C( 40 Ca,p3n) reactions. The 48 Mn decay spectroscopy was performed simultaneously in two beam lines of the mass separator. (G.P.) 13 refs.; 2 figs

Production and decay of baryonic resonances in pion induced reactions

Directory of Open Access Journals (Sweden)

Przygoda Witold

2016-01-01

Full Text Available Pion induced reactions give unique opportunities for an unambiguous description of baryonic resonances and their coupling channels. A systematic energy scan and high precision data, in conjunction with a partial wave analysis, allow for the study of the excitation function of the various contributions. A review of available world data unravels strong need for modern facilities delivering measurements with a pion beam. Recently, HADES collaboration collected data in pion-induced reactions on light (12C and heavy (74W nuclei at a beam momentum of 1.7 GeV/c dedicated to strangeness production. It was followed by a systematic scan at four different pion beam momenta (0.656, 0.69, 0.748 and 0.8 GeV/c in π− − p reaction in order to tackle the role of N(1520 resonance in conjunction with the intermediate ρ production. First results on exclusive channels with one pion (π− p and two pions (nπ+π−, pπ−π0 in the final state are discussed.

Photonuclear reactions triggered by lightning discharge.

Science.gov (United States)

Enoto, Teruaki; Wada, Yuuki; Furuta, Yoshihiro; Nakazawa, Kazuhiro; Yuasa, Takayuki; Okuda, Kazufumi; Makishima, Kazuo; Sato, Mitsuteru; Sato, Yousuke; Nakano, Toshio; Umemoto, Daigo; Tsuchiya, Harufumi

2017-11-22

Lightning and thunderclouds are natural particle accelerators. Avalanches of relativistic runaway electrons, which develop in electric fields within thunderclouds, emit bremsstrahlung γ-rays. These γ-rays have been detected by ground-based observatories, by airborne detectors and as terrestrial γ-ray flashes from space. The energy of the γ-rays is sufficiently high that they can trigger atmospheric photonuclear reactions that produce neutrons and eventually positrons via β + decay of the unstable radioactive isotopes, most notably 13 N, which is generated via 14 N + γ →  13 N + n, where γ denotes a photon and n a neutron. However, this reaction has hitherto not been observed conclusively, despite increasing observational evidence of neutrons and positrons that are presumably derived from such reactions. Here we report ground-based observations of neutron and positron signals after lightning. During a thunderstorm on 6 February 2017 in Japan, a γ-ray flash with a duration of less than one millisecond was detected at our monitoring sites 0.5-1.7 kilometres away from the lightning. The subsequent γ-ray afterglow subsided quickly, with an exponential decay constant of 40-60 milliseconds, and was followed by prolonged line emission at about 0.511 megaelectronvolts, which lasted for a minute. The observed decay timescale and spectral cutoff at about 10 megaelectronvolts of the γ-ray afterglow are well explained by de-excitation γ-rays from nuclei excited by neutron capture. The centre energy of the prolonged line emission corresponds to electron-positron annihilation, providing conclusive evidence of positrons being produced after the lightning.

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M ☉ BINARIES

International Nuclear Information System (INIS)

Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

2013-01-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M ☉ —are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ☉ . Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ☉ binaries have systematically shorter periods than do 1 M ☉ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple

Classification of decays involving variable decay chains with convolutional architectures

CERN Multimedia

CERN. Geneva

2018-01-01

Vidyo contribution We present a technique to perform classification of decays that exhibit decay chains involving a variable number of particles, which include a broad class of $B$ meson decays sensitive to new physics. The utility of such decays as a probe of the Standard Model is dependent upon accurate determination of the decay rate, which is challenged by the combinatorial background arising in high-multiplicity decay modes. In our model, each particle in the decay event is represented as a fixed-dimensional vector of feature attributes, forming an $n \\times k$ representation of the event, where $n$ is the number of particles in the event and $k$ is the dimensionality of the feature vector. A convolutional architecture is used to capture dependencies between the embedded particle representations and perform the final classification. The proposed model performs outperforms standard machine learning approaches based on Monte Carlo studies across a range of variable final-state decays with the Belle II det...

Measurement of the reaction γd →pnπ+π- at SAPHIR and investigation of the decay angular distribution of the Δ++(1232) resonance

International Nuclear Information System (INIS)

Schuetz, P.

1993-03-01

SAPHIR, a new experiment at the Bonn electron stretcher ring ELSA, started taking data in spring 1992. It was set up for the investigation of photon induced reactions with multiparticle final states. In the first part of this paper the special design of the target is described. It can be operated with liquefied hydrogen or deuterium and is placed in the middle of the central drift chamber. To project the surrounding chamber in case of a fracture of the target cell as safety system is installed. In addition two independent methods of monitoring the cell are procided. The first measurement was performed with a deuterium target at a photon energy range of E γ = 500-700 MeV. In the second part of this paper first results of an analysis of the decay angular distribution of the Δ ++ (1232) in the reaction γd → nΔ ++ π - are presented. They are compared to old data from a hydrogen bubble chamber experiment and are discussed on the basis of a spectator model. (orig.) [de

Langevin dynamics of A+A reactions in one dimension

International Nuclear Information System (INIS)

Sancho, J M; Romero, A H; Lacasta, A M; Lindenberg, Katja

2007-01-01

We propose a set of Langevin equations of motion together with a reaction rule for the study of binary reactions. Our scheme is designed to address this problem for arbitrary friction γ and temperature T. It easily accommodates the inclusion of a substrate potential, and it lends itself to straightforward numerical integration. We test this approach on diffusion-limited (γ → ∞) as well as ballistic (γ = 0) A+A → P reactions for which there are extensive exact and approximate theoretical results as well as extensive Monte Carlo results. We reproduce the known results using our integration scheme, and also present new results for the ballistic reactions

Feasibility study on the open charm rare decay at PANDA

Energy Technology Data Exchange (ETDEWEB)

Kang, Donghee [Helmholtz Institut Mainz, Universitaet Mainz (Germany); Denig, Achim [Institut fuer Kernphysik, Universitaet Mainz (Germany); Collaboration: PANDA-Collaboration

2015-07-01

In the Standard Model (SM), Flavor Changing Neutral Currents (FCNC) are forbidden at the tree level and highly suppressed at the loop level by the GIM mechanism. Studies of such FCNC decay processes provide a sensitive probe of New Physics (NP) beyond the SM. Some of the SM extensions predict that the branching ratios of FCNC decays can be significantly enhanced by NP sources. We investigate the potential of rare charm decays to constrain the extension of the SM. A search for the FCNC decays of neutral D{sup 0} into two photons and two leptons or including radiative photon could be an opportunity to pursue with PANDA since electroweak channels involving photons in the final state are competitive with ongoing experiments. The event selection in the the environment of hadronic reactions is challenging, since the ratio between signal and background of about 10 orders of magnitude requires an effective background rejection. Results on the rare decay modes D{sup 0} → γγ and D{sup 0} → μ{sup +}μ{sup -} (γ) are presented, which were obtained using Monte Carlo simulations of the PANDA experiment. In this presentation, we perform an evaluation of upper limits of branching ratios incorporating previous experiments in sensitivity.

α-ternary decay of Cf isotopes, statistical model

International Nuclear Information System (INIS)

Joseph, Jayesh George; Santhosh, K.P.

2017-01-01

The process of splitting a heavier nucleus to three simultaneous fragments is termed as ternary fission and compared to usual binary fission, it is a rare process. Depending on the nature of third particle either it is called light charged particle (LCP) accompanying fission if it is light or true ternary fission if all three fragments have nearly same mass distributions. After experimental observations in early seventies, initially with a slow pace, now theoretical studies in ternary fission has turned to a hot topic in nuclear decay studies especially in past one decade. Mean while various models have been developed, existing being modified and seeking for new with a hope that it can beam a little more light to the profound nature of nuclear interaction. In this study a statistical method, level density formulation, has been employed

Spectral properties of binary asteroids

Science.gov (United States)

Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

2018-04-01

We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

Gravitational radiation reaction

International Nuclear Information System (INIS)

Tanaka, Takahiro

2006-01-01

We give a short personally-biased review on the recent progress in our understanding of gravitational radiation reaction acting on a point particle orbiting a black hole. The main motivation of this study is to obtain sufficiently precise gravitational waveforms from inspiraling binary compact starts with a large mass ratio. For this purpose, various new concepts and techniques have been developed to compute the orbital evolution taking into account the gravitational self-force. Combining these ideas with a few supplementary new ideas, we try to outline a path to our goal here. (author)

Alpha decay as a strong collective phenomenon

International Nuclear Information System (INIS)

Bulgac, A.; Carstoiu, F.; Dumitrescu, O.; Holan, S.

1979-05-01

A theory of the α-decay in terms of irreducible reaction amplitude of the α-particle formation in the four particle channel (Tsub(4→α)) is given. By inserting a new universal constant determined by the coupling interaction between the many body Fermi liquid state and the α-cluster state we have calculated the α-widths for some favoured and unfavoured α-transitions in the translead region. Good agreement with the experimental data is obtained. (author)

Proton decay theory

International Nuclear Information System (INIS)

Marciano, W.J.

1983-01-01

Topics include minimal SU(5) predictions, gauge boson mediated proton decay, uncertainties in tau/sub p/, Higgs scalar effects, proton decay via Higgs scalars, supersymmetric SU(5), dimension 5 operators and proton decay, and Higgs scalars and proton decay

Study of the p+{sup 12}C reaction at energies up to 30 MeV

Energy Technology Data Exchange (ETDEWEB)

Harada, Masahide; Yamamoto, A.; Yoshioka, S. [Kyushu Univ., Fukuoka (Japan)] [and others

1998-03-01

Double differential cross sections of charged-particles emitted in the p+{sup 12}C reaction were measured in the energy region from 14 to 26 MeV. The observed continuous components of emitted protons and {alpha}-particles were analyzed by assuming sequential decay of intermediate reaction products and/or simultaneous breakup process. It was found that the three body simultaneous decay, p+{alpha}+{sup 8}Be, and the sequential decay via p+{sup 12}C{sup *}{sub 3-} and {alpha}+{sup 9}B{sub g.s.} are most important in the proton-induced breakup of {sup 12}C for energies up to 30 MeV. (author)

Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries

Science.gov (United States)

Evans, Nancy Evans; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan

2013-10-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ~5 M ⊙—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ⊙. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ⊙ binaries have systematically shorter periods than do 1 M ⊙ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

International Nuclear Information System (INIS)

Samsing, Johan; MacLeod, Morgan; Ramirez-Ruiz, Enrico

2014-01-01

The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a 2/7 . Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

Branching ratio of the electromagnetic decay of the Σ+(1385)

Science.gov (United States)

Keller, D.; Hicks, K.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bookwalter, C.; Boiarinov, S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Djalali, C.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, A.; Kubarovsky, V.; Kuleshov, S. V.; Lu, H. Y.; MacGregor, I. J. D.; Mao, Y.; Markov, N.; Mayer, M.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tkachenko, S.; Vernarsky, B.; Vineyard, M. F.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Watts, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhao, B.; Zhao, Z. W.

2012-03-01

The CLAS detector was used to obtain the first ever measurement of the electromagnetic decay of the Σ*+(1385) from the reaction γp→K0Σ*+(1385). A real photon beam with a maximum energy of 3.8 GeV was incident on a liquid-hydrogen target, resulting in the photoproduction of the kaon and Σ* hyperon. Kinematic fitting was used to separate the reaction channel from the background processes. The fitting algorithm exploited a new method to kinematically fit neutrons in the CLAS detector, leading to the measured decay widths ratio Σ+(1385)→Σ+γ/Σ+(1385)→Σ+π0=11.95±2.21(stat)-1.21+0.53(sys)% and a deduced partial width of 250.0±56.9(stat)-41.2+34.3(sys)keV. A U-spin symmetry test using the SU(3) flavor-multiplet representation yields predictions for the Σ*+(1385)→Σ+γ and Σ*0(1385)→Λγ partial widths that agree with the experimental measurements.

β-decay properties in the Cs decay chain

Science.gov (United States)

Benzoni, G.; Lică, R.; Borge, M. J. G.; Fraile, L. M.; IDS Collaboration

2018-02-01

The study of the decay of neutron-rich Cs isotopes has two main objectives: on one side β decay is a perfect tool to access the low-spin structures in the daughter Ba nuclei, where the evolution of octupole deformed shapes can be followed, while, on the other hand, the study of the gross properties of these decays, in terms of decay rates and branching to delayed-neutron emission, are fundamental inputs for the modelling of the r-process in the Rare-Earth Elements peak. Results obtained at CERN-ISOLDE are discussed within this framework and compared to existing data and predictions from state-of-the-art nuclear models.

Decay modes of high-lying single-particle states in 209Pb

International Nuclear Information System (INIS)

Beaumel, D.; Fortier, S.; Gales, S.; Guillot, J.; Crawley, G.M.; Massolo, C.P.; Renteria, M.

1993-01-01

The neutron decay of high-lying single-particle states in 209 Pb excited by means of the (α, 3 He) reaction has been investigated at 122 MeV incident energy using the multidetector array EDEN. The high spin values of these states, inferred from previous inclusive experiments, are confirmed by the present data involving angular correlation measurements and the determination of branching ratios to low lying levels in 208 Pb. The structure located between 8.5 and 12 MeV excitation energy in 209 Pb displays large departures from a pure statistical decay with significant direct feeding of the low-lying collective states (3 - ,5 - ) of 208 Pb. At higher excitation energy up to 20 MeV, the measured neutron decay is in agreement with the predictions of the statistical model. (authors). 24 refs., 16 figs., 2 tabs

Foundations and models of pre-equilibrium decay

International Nuclear Information System (INIS)

Bunakov, V.E.

1980-01-01

A review is given of the presently existing microscopic, semi-phenomenologic and phenomenologic models used for the description of nuclear reactions. Their advantages and drawbacks are analyzed. A special attention is given to the analysis of pre-equilibrium decay phenomenological models based on the use of master equations (time-dependent versions of exciton models, intranuclear cascade, etc.). A version of the unified theory of nuclear reactions is discussed which makes use of quantum master equations for finite open systems. The conditions are formulated for the derivation of these equations from the time-dependent Schroedinger equation for the many-body problem. The various models of nuclear reactions used in practice are shown to be approximate solutions of master equations for finite open systems. From this point of view the analysis is carried out of these models' reliability in the description of experimental data. Possible modifications are considered which provide for better agreement between the different models and for the more exact description of experimental data. (author)

Excited state intramolecular charge transfer reaction in binary mixtures of water and tertiary butanol (TBA): alcohol mole fraction dependence.

Science.gov (United States)

Pradhan, Tuhin; Ghoshal, Piue; Biswas, Ranjit

2008-02-07

The excited state intramolecular charge transfer reaction of 4-(1-azetidinyl)benzonitrile (P4C) has been studied in water-tertiary butanol (TBA) mixtures at different alcohol mole fractions by using steady state and time-resolved fluorescence spectroscopy. The ratio between the areas under the locally excited (LE) and charge transferred (CT) emission bands is found to exhibit a sharp rise at alcohol mole fraction approximately 0.04, a value at which several thermodynamic properties of this mixture is known to show anomalous change due to the enhancement of H-bonding network. The radiative rate associated with the LE emission also shows a maximum at this TBA mole fraction. Although the structural transition from the water-like tetrahedral network to the alcohol-like chain is reflected in the red shift of the absorption spectrum up to TBA mole fraction approximately 0.10, the emission bands (both LE and CT) show the typical nonideal alcohol mole fraction dependence at all TBA mole fractions. Quantum yield, CT radiative rate as well as transition moments also exhibit a nonideal alcohol mole fraction dependence. The time-resolved emission decay of P4C has been found to be biexponential at all TBA mole fractions, regardless of emission collection around either the LE or the CT bands. The time constant associated with the slow component (tau(slow)) shows a minimum at TBA mole fraction approximately 0.04, whereas such a minimum for the fast time constant, tau(fast) (representing the rate of LE --> CT conversion reaction) is not observed. The nonobservation of the minimum in tau(fast) might be due to the limited time resolution employed in our experiments.

N-Bit Binary Resistor

Science.gov (United States)

Tcheng, Ping

1989-01-01

Binary resistors in series tailored to precise value of resistance. Desired value of resistance obtained by cutting appropriate traces across resistors. Multibit, binary-based, adjustable resistor with high resolution used in many applications where precise resistance required.

Does increasing pressure always accelerate the condensed material decay initiated through bimolecular reactions? A case of the thermal decomposition of TKX-50 at high pressures.

Science.gov (United States)

Lu, Zhipeng; Zeng, Qun; Xue, Xianggui; Zhang, Zengming; Nie, Fude; Zhang, Chaoyang

2017-08-30

Performances and behaviors under high temperature-high pressure conditions are fundamentals for many materials. We study in the present work the pressure effect on the thermal decomposition of a new energetic ionic salt (EIS), TKX-50, by confining samples in a diamond anvil cell, using Raman spectroscopy measurements and ab initio simulations. As a result, we find a quadratic increase in decomposition temperature (T d ) of TKX-50 with increasing pressure (P) (T d = 6.28P 2 + 12.94P + 493.33, T d and P in K and GPa, respectively, and R 2 = 0.995) and the decomposition under various pressures initiated by an intermolecular H-transfer reaction (a bimolecular reaction). Surprisingly, this finding is contrary to a general observation about the pressure effect on the decomposition of common energetic materials (EMs) composed of neutral molecules: increasing pressure will impede the decomposition if it starts from a bimolecular reaction. Our results also demonstrate that increasing pressure impedes the H-transfer via the enhanced long-range electrostatic repulsion of H +δ H +δ of neighboring NH 3 OH + , with blue shifts of the intermolecular H-bonds. And the subsequent decomposition of the H-transferred intermediates is also suppressed, because the decomposition proceeds from a bimolecular reaction to a unimolecular one, which is generally prevented by compression. These two factors are the basic root for which the decomposition retarded with increasing pressure of TKX-50. Therefore, our finding breaks through the previously proposed concept that, for the condensed materials, increasing pressure will accelerate the thermal decomposition initiated by bimolecular reactions, and reveals a distinct mechanism of the pressure effect on thermal decomposition. That is to say, increasing pressure does not always promote the condensed material decay initiated through bimolecular reactions. Moreover, such a mechanism may be feasible to other EISs due to the similar intermolecular

Some properties of spectral binary stars

International Nuclear Information System (INIS)

Krajcheva, Z.T.; Popova, E.I.; Tutukov, A.V.; Yungel'son, L.R.; AN SSSR, Moscow. Astronomicheskij Sovet)

1978-01-01

Statistical investigations of spectra binary stars are carried out. Binary systems consisting of main sequence stars are considered. For 826 binary stars masses of components, ratios of component masses, semiaxes of orbits and orbital angular momenta are calculated. The distributions of these parameters and their correlations are analyzed. The dependences of statistical properties of spectral binary stars on their origin and evolution are discussed

K X-rays and nuclear reaction times in the deep inelastic reactions U+U and U+Pb at 7.5 MeV/amu

International Nuclear Information System (INIS)

Stoller, C.

1985-01-01

The K-shell ionisation probability of the heavy reaction products emerging from binary deep inelastic collisions of U + U and U + Pb at 7.5 MeV/amu has been measured as a function of the total kinetic energy loss - Q. After subtraction of the ionisation probability due to internal conversion of γ-rays, a strongly Q-dependent Psub(K) is found, in agreement with theoretical predictions relating the change in ionisation probability to the nuclear sticking time. The deduced nuclear reaction times are in qualitative agreement with predictions from nuclear models of deep inelastic reactions. (orig.)

Angular correlation measurements for 4-{alpha} decaying states in {sup 16}O

Energy Technology Data Exchange (ETDEWEB)

Wuosmaa, A.H.; Back, B.B.; Betts, R.R. [and others

1995-08-01

Previous measurements of the {sup 12}C({sup 12}C,{sup 8}Be){sup 16}O{sup *}(4 {alpha}) reaction identified discrete levels in {sup 16}O which decay by breakup into 4 {alpha} particles through a number of different decay sequences, including {sup 16}O{sup *} {yields} {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C (O{sub 2}{sup +}). These states are observed in a range of excitation energies where resonances are observed in inelastic {alpha} + {sup 12}C scattering leading to the {sup 8}Be + {sup 8}Be and {alpha} + {sup 12}C final states. These resonances were associated with 4 {alpha}-particle chain configurations in {sup 16}O. Should the states populated in the {sup 12}C + {sup 12}C reaction possess this same extended structure, it would serve as an important piece of evidence supporting the idea that even more deformed structures are formed in the {sup 24}Mg compound system. In order to more firmly make this association, it is important to determine the spins of the states populated in the {sup 12}C + {sup 12}C reaction.

Investigations of nuclear structure and nuclear reactions induced by complex projectiles

International Nuclear Information System (INIS)

Sarantites, D.G.

1993-01-01

This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in 82 Sr; structure of and identical bands in 182 Hg and 178 Pt; a highly deformed band in 136 Pm; particle decay of the 164 Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of 12 O; modeling and theoretical studies; excited 16 O disassembly into four alpha particles; 209 Bi + 136 Xe collisions at 28.2 MeV/amu; and development work on 4π solid angle gamma detectors, and x-ray detectors

DECAY MODES OF HIGH-LYING SINGLE-PARTICLE STATES IN PB-209

NARCIS (Netherlands)

BEAUMEL, D; FORTIER, S; GALES, S; GUILLOT, J; LANGEVINJOLIOT, H; LAURENT, H; MAISON, JM; VERNOTTE, J; BORDEWIJK, JA; BRANDENBURG, S; KRASZNAHORKAY, A; CRAWLEY, GM; MASSOLO, CP; RENTERIA, M

The neutron decay of high-lying single-particle states in Pb-209 excited by means of the (alpha, He-3) reaction has been investigated at 122 MeV incident energy using a multidetector array. The high-spin values of these states, inferred from previous inclusive experiments, are confirmed by the

Microlensing Binaries Discovered through High-magnification Channel

DEFF Research Database (Denmark)

Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.

2012-01-01

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturba......Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010...

Nuclear fission, chain reaction and criticality

International Nuclear Information System (INIS)

Reuss, Paul

2016-01-01

Criticality is, notably for nuclear reactors, the status which separates the case of a fission chain reaction which inexorably decays, from that of a reaction which grows faster and faster until a counter-reaction occurs. If this status is an objective in nuclear reactors, it must not be reached or exceeded in any case in other types of installations in which fissile materials are handled (fabrication, transports, nuclear fuel processing). The author proposes an insight into this notion of criticality, discusses elements of neutron science which allow the multiplication factor to be assessed, analyses accidental scenarios which may happen, and presents associated experiments and computation codes

Non-Born-Oppenheimer trajectories with self-consistent decay of mixing

International Nuclear Information System (INIS)

Zhu Chaoyuan; Jasper, Ahren W.; Truhlar, Donald G.

2004-01-01

A semiclassical trajectory method, called the self-consistent decay of mixing (SCDM) method, is presented for the treatment of electronically nonadiabatic dynamics. The SCDM method is a modification of the semiclassical Ehrenfest (SE) method (also called the semiclassical time-dependent self-consistent-field method) that solves the problem of unphysical mixed final states by including decay-of-mixing terms in the equations for the evolution of the electronic state populations. These terms generate a force, called the decoherent force (or dephasing force), that drives the electronic component of each trajectory toward a pure state. Results for several mixed quantum-classical methods, in particular the SCDM, SE, and natural-decay-of-mixing methods and several trajectory surface hopping methods, are compared to the results of accurate quantum mechanical calculations for 12 cases involving five different fully dimensional triatomic model systems. The SCDM method is found to be the most accurate of the methods tested. The method should be useful for the simulation of photochemical reactions

Performance analysis and binary working fluid selection of combined flash-binary geothermal cycle

International Nuclear Information System (INIS)

Zeyghami, Mehdi

2015-01-01

Performance of the combined flash-binary geothermal power cycle for geofluid temperatures between 150 and 250 °C is studied. A thermodynamic model is developed, and the suitable binary working fluids for different geofluid temperatures are identified from a list of thirty working fluid candidates, consisting environmental friendly refrigerants and hydrocarbons. The overall system exergy destruction and Vapor Expansion Ratio across the binary cycle turbine are selected as key performance indicators. The results show that for low-temperature heat sources using refrigerants as binary working fluids result in higher overall cycle efficiency and for medium and high-temperature resources, hydrocarbons are more suitable. For combined flash-binary cycle, secondary working fluids; R-152a, Butane and Cis-butane show the best performances at geofluid temperatures 150, 200 and 250 °C respectively. The overall second law efficiency is calculated as high as 0.48, 0.55 and 0.58 for geofluid temperatures equal 150, 200 and 250 °C respectively. The flash separator pressure found to has important effects on cycle operation and performance. Separator pressure dictates the work production share of steam and binary parts of the system. And there is an optimal separator pressure at which overall exergy destruction of the cycle achieves its minimum value. - Highlights: • Performance of the combined flash-binary geothermal cycle is investigated. • Thirty different fluids are screened to find the most suitable ORC working fluid. • Optimum cycle operation conditions presented for geofluids between 150 °C and 250 °C. • Refrigerants are more suitable for the ORC at geothermal sources temperature ≤200 °C. • Hydrocarbons are more suitable for the ORC at geothermal sources temperature >200 °C

BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M {sub ☉} BINARIES

Energy Technology Data Exchange (ETDEWEB)

Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan [Smithsonian Astrophysical Observatory, MS 4, 60 Garden Street, Cambridge, MA 02138 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Schaefer, Gail H. [The CHARA Array, Georgia State University, P.O. Box 3965, Atlanta, GA 30302-3965 (United States); Mason, Brian D., E-mail: nevans@cfa.harvard.edu, E-mail: heb11@psu.edu, E-mail: schaefer@chara-array.org [US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

2013-10-01

Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M {sub ☉}—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M {sub ☉}. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M {sub ☉} binaries have systematically shorter periods than do 1 M {sub ☉} stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple.

Mesoporous CuO–ZnO binary metal oxide nanocomposite for decontamination of sulfur mustard

International Nuclear Information System (INIS)

Praveen Kumar, J.; Prasad, G.K.; Ramacharyulu, P.V.R.K.; Garg, P.; Ganesan, K.

2013-01-01

Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. They were prepared by precipitation pyrolysis method and characterized by means of X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared spectroscopy techniques. Obtained data indicated the presence of mesopores with diameter ranging from 2 to 80 nm and the materials exhibited relatively high surface area 86 m 2 g −1 when compared to the individual metal oxide nanoparticles. Reactive sites of mesoporous CuO–ZnO binary metal oxide nanocomposites were studied by infrared spectroscopy technique using pyridine as a probe molecule. These materials demonstrated superior decontamination properties against sulfur mustard when compared to single component metal oxides and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Graphical abstract: Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. These materials demonstrated superior decontamination properties against sulfur mustard and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Highlights: • Preparation of mesoporous CuO–ZnO binary metal oxide nanocomposite. • CuO–ZnO with better surface area was synthesized by precipitation pyrolysis. • Decontamination of HD using mesoporous CuO–ZnO binary metal oxide nanocomposite. • HD decontaminated by elimination and hydrolysis reactions

Mesoporous CuO–ZnO binary metal oxide nanocomposite for decontamination of sulfur mustard

Energy Technology Data Exchange (ETDEWEB)

Praveen Kumar, J.; Prasad, G.K., E-mail: gkprasad2001@yahoo.com; Ramacharyulu, P.V.R.K.; Garg, P.; Ganesan, K.

2013-11-01

Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. They were prepared by precipitation pyrolysis method and characterized by means of X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared spectroscopy techniques. Obtained data indicated the presence of mesopores with diameter ranging from 2 to 80 nm and the materials exhibited relatively high surface area 86 m{sup 2} g{sup −1} when compared to the individual metal oxide nanoparticles. Reactive sites of mesoporous CuO–ZnO binary metal oxide nanocomposites were studied by infrared spectroscopy technique using pyridine as a probe molecule. These materials demonstrated superior decontamination properties against sulfur mustard when compared to single component metal oxides and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Graphical abstract: Mesoporous CuO–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard, a well known chemical warfare agent. These materials demonstrated superior decontamination properties against sulfur mustard and decontaminated it to divinyl sulfide, chloroethyl vinyl sulfide, hemisulfur mustard, etc. - Highlights: • Preparation of mesoporous CuO–ZnO binary metal oxide nanocomposite. • CuO–ZnO with better surface area was synthesized by precipitation pyrolysis. • Decontamination of HD using mesoporous CuO–ZnO binary metal oxide nanocomposite. • HD decontaminated by elimination and hydrolysis reactions.

Decay out of the superdeformed band in {sup 143}Eu

Energy Technology Data Exchange (ETDEWEB)

Atac, A; Piiparinen, M; Herskind, B [Copenhagen Univ. (Denmark); and others

1992-08-01

The connection between the super-deformed (SD) and normal-deformed (ND) states had not been observed, owing its difficulty to a statistical, highly fragmented decay path out of the SD bands. This left both the spin and the excitation energy of the SD bands undetermined. In this paper, the authors present results of a new experimental approach, where they take advantage of triple and higher-fold coincidences to study the decay-out of a SD band. They carried out an experiment at the Niels Bohr Institute Tandem Accelerator Laboratory, where they used the (160 MeV) {sup 37}Cl + {sup 110}Pd {yields} {sup 143}Eu + 4n reaction. 9 refs., 3 figs.

Dissipative binary collisions

International Nuclear Information System (INIS)

Aboufirassi, M; Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Meslin, C.; Metivier, V.; Nakagawa, T.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Wieloch, A.; Yuasa-Nakagawa, K.

1998-01-01

The binary character of the heavy ion collisions at intermediate energies in the exit channel has been observed under 30 MeV/n in medium and heavy systems. Measurements in light systems at energies approaching ∼ 100 MeV/nucleon as well as in very heavy systems have allowed to extend considerably the investigations of this binary process. Thus, the study of the Pb + Au system showed that the complete charge events indicated two distinct sources: the quasi-projectile and the quasi-target. The characteristics of these two sources are rather well reproduced by a trajectory computation which takes into account the Coulomb and nuclear forces and the friction appearing from the projectile-target interaction. The Wilczynski diagram is used to probe the correlation between the kinetic energy quenching and the deflecting angle. In case of the system Pb + Au at 29 MeV/nucleon the diagram indicate dissipative binary collisions typical for low energies. This binary aspect was also detected in the systems Xe + Ag at 44 MeV/nucleon, 36 Ar + 27 Al and 64 Zn + nat Ti. Thus, it was possible to reconstruct the quasi-projectile and to study its mass and excitation energy evolution as a function of the impact parameter. The dissipative binary collisions represent for the systems and energies under considerations the main contribution to the cross section. This does not implies that there are not other processes; particularly, the more or less complete fusion is also observed but with a low cross section which decreases with the increase of bombardment energy. More exclusive measurements with the INDRA detector on quasi-symmetric systems as Ar + KCl and Xe + Sn seem to confirm the importance of the binary collisions. The two source reconstruction of the Xe + Sn data at 50 MeV/nucleon reproduces the same behaviour as that observed in the system Pb + Au at 29 MeV/nucleon

Contact Binaries on Their Way Towards Merging

Science.gov (United States)

Gazeas, K.

2015-07-01

Contact binaries are the most frequently observed type of eclipsing star system. They are small, cool, low-mass binaries belonging to a relatively old stellar population. They follow certain empirical relationships that closely connect a number of physical parameters with each other, largely because of constraints coming from the Roche geometry. As a result, contact binaries provide an excellent test of stellar evolution, specifically for stellar merger scenarios. Observing campaigns by many authors have led to the cataloging of thousands of contact binaries and enabled statistical studies of many of their properties. A large number of contact binaries have been found to exhibit extraordinary behavior, requiring follow-up observations to study their peculiarities in detail. For example, a doubly-eclipsing quadruple system consisting of a contact binary and a detached binary is a highly constrained system offering an excellent laboratory to test evolutionary theories for binaries. A new observing project was initiated at the University of Athens in 2012 in order to investigate the possible lower limit for the orbital period of binary systems before coalescence, prior to merging.

JENDL FP decay data file 2000 and the beta-decay theory

International Nuclear Information System (INIS)

Yoshida, Tadashi; Katakura, Jun Ichi; Tachibana, Takahiro

2002-01-01

JENDL FP Decay Data File 2000 has been developed as one of the special purpose files of the Japanese Evaluated Nuclear Data Library (JENDL), which constitutes a versatile nuclear data basis for science and technology. In the format of ENDF-6 this file includes the decay data for 1087 unstable fission product (FP) nuclides and 142 stable nuclides as their daughters. The primary purpose of this file is to use in the summation calculation of FP decay heat, which plays a critical role in nuclear safety analysis; the loss-of-coolant accident analysis of reactors, for example. The data for a given nuclide are its decay modes, the Q value, the branching ratios, the average energies released in the form of beta- and gamma-rays per decay, and their spectral data. The primary source of the decay data adopted here is the ENSDF (Evaluated Nuclear Structure Data File). The data in ENSDF, however, cover only the measured values. The data of the short-lived nuclides, which are essential for the decay heat calculations at short cooling times, are often fully lacking or incomplete even if they exist. This is mainly because of their short half-life nature. For such nuclides a theoretical model calculation is applied in order to fill the gaps between the true and the experimentally known decay schemes. In practice we have to predict the average decay energies and the spectral data for a lot of short-lived FPs by use of beta-decay theories. Thus the beta-decay theory plays a very important role in generating the FP decay data file

Measurement of HOx· production rate due to radon decay in air

International Nuclear Information System (INIS)

Ding, Huiling.

1993-08-01

Radon in indoor air may cause the exposure of the public to excessive radioactivity. Radiolysis of water vapor in indoor air due to radon decay could produce (·OH and HO 2 ·) that may convert atmospheric constituents to compounds of lower vapor pressure. These lower vapor pressure compounds might then nucleate to form new particles in the indoor atmosphere. Chemical amplification was used to determine HO x · production rate in indoor air caused by radon decay. Average HO x · production rate was found to be (4.31±0.07) x 10 5 HO x · per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G (HO x ·) -value, 7.86±0.13 No./100 eV in air by directly measuring [HO x ·] formed from the radiolysis procedure. This G value implies that HO x · produced by radon decay in air might be formed by multiple processes and may be result of positive ion-molecule reactions, primary radiolysis, and radical reactions. There is no obvious relation between HO x · production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for ·OH production rate measurement; it consists of an excimer laser, a dye laser, a frequency doubler, a gaseous fluorescence chamber, and other optical and electronic parts. This system needs to be improved to eliminate the interferences of light scattering and artificial ·OH produced from the photolysis of O 3 /H 2 O

Permutation Entropy for Random Binary Sequences

Directory of Open Access Journals (Sweden)

Lingfeng Liu

2015-12-01

Full Text Available In this paper, we generalize the permutation entropy (PE measure to binary sequences, which is based on Shannon’s entropy, and theoretically analyze this measure for random binary sequences. We deduce the theoretical value of PE for random binary sequences, which can be used to measure the randomness of binary sequences. We also reveal the relationship between this PE measure with other randomness measures, such as Shannon’s entropy and Lempel–Ziv complexity. The results show that PE is consistent with these two measures. Furthermore, we use PE as one of the randomness measures to evaluate the randomness of chaotic binary sequences.

Water-based binary polyol process for the controllable synthesis of silver nanoparticles inhibiting human and foodborne pathogenic bacteria

Science.gov (United States)

The polyol process is a widely used strategy for producing nanoparticles from various reducible metallic precursors; however it requires a bulk polyol liquid reaction with additional protective agents at high temperatures. Here, we report a water-based binary polyol process using low concentrations ...

Hydrodynamic 'memory' of binary fluid mixtures

International Nuclear Information System (INIS)

Kalashnik, M. V.; Ingel, L. Kh.

2006-01-01

A theoretical analysis is presented of hydrostatic adjustment in a two-component fluid system, such as seawater stratified with respect to temperature and salinity. Both linear approximation and nonlinear problem are investigated. It is shown that scenarios of relaxation to a hydrostatically balanced state in binary fluid mixtures may substantially differ from hydrostatic adjustment in fluids that can be stratified only with respect to temperature. In particular, inviscid two-component fluids have 'memory': a horizontally nonuniform disturbance in the initial temperature or salinity distribution does not vanish even at the final stage, transforming into a persistent thermohaline 'trace.' Despite stability of density stratification and convective stability of the fluid system by all known criteria, an initial temperature disturbance may not decay and may even increase in amplitude. Moreover, its sign may change (depending on the relative contributions of temperature and salinity to stable background density stratification). Hydrostatic adjustment may involve development of discontinuous distributions from smooth initial temperature or concentration distributions. These properties of two-component fluids explain, in particular, the occurrence of persistent horizontally or vertically nonuniform temperature and salinity distributions in the ocean, including discontinuous ones

Binary Systems and the Initial Mass Function

Science.gov (United States)

Malkov, O. Yu.

2017-07-01

In the present paper we discuss advantages and disadvantages of binary stars, which are important for star formation history determination. We show that to make definite conclusions of the initial mass function shape, it is necessary to study binary population well enough to correct the luminosity function for unresolved binaries; to construct the mass-luminosity relation based on wide binaries data, and to separate observational mass functions of primaries, of secondaries, and of unresolved binaries.

Accuracy of binary black hole waveform models for aligned-spin binaries

Science.gov (United States)

Kumar, Prayush; Chu, Tony; Fong, Heather; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela

2016-05-01

Coalescing binary black holes are among the primary science targets for second generation ground-based gravitational wave detectors. Reliable gravitational waveform models are central to detection of such systems and subsequent parameter estimation. This paper performs a comprehensive analysis of the accuracy of recent waveform models for binary black holes with aligned spins, utilizing a new set of 84 high-accuracy numerical relativity simulations. Our analysis covers comparable mass binaries (mass-ratio 1 ≤q ≤3 ), and samples independently both black hole spins up to a dimensionless spin magnitude of 0.9 for equal-mass binaries and 0.85 for unequal mass binaries. Furthermore, we focus on the high-mass regime (total mass ≳50 M⊙ ). The two most recent waveform models considered (PhenomD and SEOBNRv2) both perform very well for signal detection, losing less than 0.5% of the recoverable signal-to-noise ratio ρ , except that SEOBNRv2's efficiency drops slightly for both black hole spins aligned at large magnitude. For parameter estimation, modeling inaccuracies of the SEOBNRv2 model are found to be smaller than systematic uncertainties for moderately strong GW events up to roughly ρ ≲15 . PhenomD's modeling errors are found to be smaller than SEOBNRv2's, and are generally irrelevant for ρ ≲20 . Both models' accuracy deteriorates with increased mass ratio, and when at least one black hole spin is large and aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical relativity simulation in the merger phase, for unequal masses and simultaneously both black hole spins very large and aligned. Two older waveform models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected from all four waveform models during parameter estimation for several recovered binary parameters: chirp mass, mass ratio, and effective spin.

Radial Velocities of 41 Kepler Eclipsing Binaries

Science.gov (United States)

Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Williams, Stephen J.

2017-12-01

Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA’s Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-lined systems, and confirm one false positive eclipsing binary. For the double-lined spectroscopic binaries, we also determine individual component masses and examine the mass ratio {M}2/{M}1 distribution, which is dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. Finally, we constrain the mass of the tertiary component for five double-lined binaries with previously detected companions.

Planets in Binary Star Systems

CERN Document Server

Haghighipour, Nader

2010-01-01

The discovery of extrasolar planets over the past decade has had major impacts on our understanding of the formation and dynamical evolution of planetary systems. There are features and characteristics unseen in our solar system and unexplainable by the current theories of planet formation and dynamics. Among these new surprises is the discovery of planets in binary and multiple-star systems. The discovery of such "binary-planetary" systems has confronted astrodynamicists with many new challenges, and has led them to re-examine the theories of planet formation and dynamics. Among these challenges are: How are planets formed in binary star systems? What would be the notion of habitability in such systems? Under what conditions can binary star systems have habitable planets? How will volatiles necessary for life appear on such planets? This volume seeks to gather the current research in the area of planets in binary and multistar systems and to familiarize readers with its associated theoretical and observation...

Theoretical studies of binaries in astrophysics

Science.gov (United States)

Dischler, Johann Sebastian

This thesis introduces and summarizes four papers dealing with computer simulations of astrophysical processes involving binaries. The first part gives the rational and theoretical background to these papers. In paper I and II a statistical approach to studying eclipsing binaries is described. By using population synthesis models for binaries the probabilities for eclipses are calculated for different luminosity classes of binaries. These are compared with Hipparcos data and they agree well if one uses a standard input distribution for the orbit sizes. If one uses a random pairing model, where both companions are independently picked from an IMF, one finds too feclipsing binaries by an order of magnitude. In paper III we investigate a possible scenario for the origin of the stars observed close to the centre of our galaxy, called S stars. We propose that a cluster falls radially cowards the central black hole. The binaries within the cluster can then, if they have small impact parameters, be broken up by the black hole's tidal held and one of the components of the binary will be captured by the black hole. Paper IV investigates how the onset of mass transfer in eccentric binaries depends on the eccentricity. To do this we have developed a new two-phase SPH scheme where very light particles are at tire outer edge of our simulated star. This enables us to get a much better resolution of the very small mass that is transferred in close binaries. Our simulations show that the minimum required distance between the stars to have mass transfer decreases with the eccentricity.

Mining frequent binary expressions

NARCIS (Netherlands)

Calders, T.; Paredaens, J.; Kambayashi, Y.; Mohania, M.K.; Tjoa, A.M.

2000-01-01

In data mining, searching for frequent patterns is a common basic operation. It forms the basis of many interesting decision support processes. In this paper we present a new type of patterns, binary expressions. Based on the properties of a specified binary test, such as reflexivity, transitivity

Close-binary central stars of planetary nebulae

International Nuclear Information System (INIS)

Bond, H.E.; Grauer, A.D.

1987-01-01

Recent observations of PN central stars identified as binary systems are reviewed. The theoretical significance of binary central stars is discussed, and the characteristics of UU Sge, V 477 Lyr, MT Ser, LSS 2018, VW Pyx, and the central star of HFG 1 are briefly summarized. All of these binaries are shown to have periods less than 1 day, and it is estimated that about 10 percent of all binary central stars are close binaries. 27 references

Measurement of the radiative decay width {gamma}[{lambda}(1520)->{lambda}{gamma}] with the SPHINX spectrometer

Energy Technology Data Exchange (ETDEWEB)

Antipov, Yu.M. [Institute for High Energy Physics, Protvino (Russian Federation); Artamonov, A.V. [Institute for High Energy Physics, Protvino (Russian Federation); Batarin, V.A. [Institute for High Energy Physics, Protvino (Russian Federation); Vavilov, D.V. [Institute for High Energy Physics, Protvino (Russian Federation); Victorov, V.A. [Institute for High Energy Physics, Protvino (Russian Federation); Eroshin, O.V. [Institute for High Energy Physics, Protvino (Russian Federation); Golovkin, S.V. [Institute for High Energy Physics, Protvino (Russian Federation); Gorin, Yu.P. [Institute for High Energy Physics, Protvino (Russian Federation); Kolganov, V.Z. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Kozhevnikov, A.P. [Institute for High Energy Physics, Protvino (Russian Federation); Konstantinov, A.S. [Institute for High Energy Physics, Protvino (Russian Federation); Kubarovsky, V.P. [Institute for High Energy Physics, Protvino (Russian Federation); Kurshetsov, V.F. [Institute for High Energy Physics, Protvino (Russian Federation); Landsberg, L.G. [Institute for High Energy Physics, Protvino (Russian Federation)]. E-mail: lgl@mx.ihep.su; Leontiev, V.M. [Institute for High Energy Physics, Protvino (Russian Federation); Lomkatsi, G.S. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Molchanov, V.V. [Institute for High Energy Physics, Protvino (Russian Federation)]. E-mail: molchanov@mx.ihep.su; Mukhin, V.A. [Institute for High Energy Physics, Protvino (Russian Federation); Nilov, A.F. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Patalakha, D.I. [Institute for High Energy Physics, Protvino (Russian Federation); Petrenko, S.V. [Institute for High Energy Physics, Protvino (Russian Federation); Smolyankin, V.T. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation)

2004-12-16

The radiative decay {lambda}(1520)->{lambda}{gamma} was measured directly in the study of the exclusive diffractive-like reaction p+N->{lambda}(1520)K{sup +}+N, {lambda}(1520)->{lambda}{gamma} with the SPHINX spectrometer. The values of the branching and partial width of this radiative decay were obtained: BR[{lambda}(1520)->{lambda}{gamma}]=(1.02+/-0.21(stat)+/-0.15(syst))x10{sup -2} and {gamma}[{lambda}(1520)->{lambda}{gamma}]=159+/-33(stat)+/-26(syst)-bar keV.

Measurement of the radiative decay width Γ[Λ(1520)->Λγ] with the SPHINX spectrometer

International Nuclear Information System (INIS)

Antipov, Yu.M.; Artamonov, A.V.; Batarin, V.A.; Vavilov, D.V.; Victorov, V.A.; Eroshin, O.V.; Golovkin, S.V.; Gorin, Yu.P.; Kolganov, V.Z.; Kozhevnikov, A.P.; Konstantinov, A.S.; Kubarovsky, V.P.; Kurshetsov, V.F.; Landsberg, L.G.; Leontiev, V.M.; Lomkatsi, G.S.; Molchanov, V.V.; Mukhin, V.A.; Nilov, A.F.; Patalakha, D.I.; Petrenko, S.V.; Smolyankin, V.T.

2004-01-01

The radiative decay Λ(1520)->Λγ was measured directly in the study of the exclusive diffractive-like reaction p+N->Λ(1520)K + +N, Λ(1520)->Λγ with the SPHINX spectrometer. The values of the branching and partial width of this radiative decay were obtained: BR[Λ(1520)->Λγ]=(1.02+/-0.21(stat)+/-0.15(syst))x10 -2 and Γ[Λ(1520)->Λγ]=159+/-33(stat)+/-26(syst)-bar keV

Perturbative QCD effects in heavy meson decays

International Nuclear Information System (INIS)

Szezepaniak, A.; Henley, E.M.

1991-01-01

The amplitude for the exclusive nonleptonic decay of a heavy meson into two light pseudoscalar mesons is analyzed using the factorization formalism of perturbative QCD for exclusive reactions at large momentum transfer. We calculate the form factor b → u transition and compare it to the old quark model calculation and the new one based on the light cone formulation of the full quark model wave function. The new results we obtain are smaller by a factor of 2 - 3 as compared to the old value. (orig.)

Radioactive decay of sup(91m)Nb

International Nuclear Information System (INIS)

Lakshminarayana, V.; Venkataratnam, S.; Rao, B.V.T.; Narasimham, K.L.

1987-01-01

The radioactive decay of sup(91m)Nb, produced by the reaction 89 Y(α, 2n), is studied using Ge(Li), HPGe and Si(Li) detectors. The K-conversion coefficient, αsub(K), of the 104.5 keV transition is determined accurately, for the first time, from the Nb Ksub(α) x-ray and 104.5 keV gamma-ray intensities. The experimental value of αsub(K) thus determined is 115(5), in agreement with the value expected for an M4 transition. (author)

Search for a non-minimal Higgs boson produced in the reaction e+e- → hZ∗

Science.gov (United States)

Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Blucher, E.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Hagelberg, R.; Harvey, J.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Lohse, T.; Maggi, M.; Markou, C.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miotto, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Tomalin, I. R.; Veenhof, R.; Wachsmuth, H.; Wasserbaech, S.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Prulhière, F.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulo, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Levinthal, D.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Vogl, R.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Nicod, D.; Papalexiou, S.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jakobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; Denis, R. St.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jaffe, D. E.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Gao, Y.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Nachtman, J. M.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I.; Sharma, V.; Shi, Z. H.; Turk, J. D.; Walsh, A. M.; Weber, F. V.; Sau Lan Wu; Wu, X.; Zheng, M.; Zobernig, G.; Aleph Collaboration

1993-08-01

A data sample corresponding to 1.23 million hadronic Z decays collected by the ALEPH detector at LEP has been searched for signals of the production of a non-minimal CP-even Higgs boson h in the reaction e+e- → hZ∗. The h decay modes considered were: those of the minimal standard model Higgs boson, with modified branching ratios; decays into a pair of CP-odd Higgs bosons A; and decays into invisible final states. Only one event was found, a very acoplanar e +e - pair which could originate from the standard model background process e+e- → e+e-v v¯. Upper limits for the cross-section of the reaction e+e- → hZ∗ have been derived as a function of mh, the mass of the Higgs boson h. In the case of invisible decays, the 95% CL lower limit on mh is 65 GeV/ c2 for a production cross-section equal to that of a minimal standard model Higgs boson. When combined with previous ALEPH results on the reaction e +e - → hA, these cross-section upper limits exclude a domain in the ( mhmA) plane of the MSSM such that if invisible h and A decays can be neglected, 95% CL lower limits of 44 and 21 GeV/ c2 result for mh and mA, respectively, independent of the other parameters of the model.

Applications of Rajeval technique for the evaluation of discrepant nuclear decay data

International Nuclear Information System (INIS)

Rajput, M.U.

2006-11-01

There are 4 levels 95NB below the decay energy in the Adopted Levels of the 93 micro 08 evaluation that are not reported in this decay scheme: these are 730 6 (5/2+), 799 5 (3/2), 1011 8 (5/2), and 1088keV. These levels have only been reported in reaction studies and their lemma decay modes are not known the 730 level would be fed fed by and allowed beta decay, so this evaluator suggests it is actually the 724 level and the J* assignment is incorrect. The failure to observe decays to the possible 799 and 1011 levels is surprising since these would be 1st forbidden decays and from beta decay systematics (73Ra10) could have branches of several percent. Therefore, one must rely on the fact that other lemda rays have not been reported to support the completeness of this scheme. If one leaves the values of 65F102 in the data set, it is desirable to use either the RAJEVAL or Normalized Residual method to treat this discrepancy. The RAJEVAL method increase the uncertainty for the 65F102 value from 0.2 to 0.88 and gives the resulting value of 64.032(6) while the Normalized Residual method increase this uncertainty to 0.58 and give a result of 64.032(6). So, the adopted value is the same for each of these three methods. (author)

Di-lepton yield from the decay of excited 28Si states

International Nuclear Information System (INIS)

Bacelar, J.C.; Buda, A.; Balanda, A.; Krasznahorkay, A.; Ploeg, H. van der; Sujkowski, Z.; Woude, A. van der

1994-01-01

The first dilepton yield measurements from excited nuclear states obtained with a new Positron-Electron Pair Spectroscopic Instrument (PEPSI) are reported. Nuclear states in 28 Si, with an initial excitation energy E * =50 MeV, were populated via the isospin T=0 reaction 4 He+ 24 Mg and the mixed-isospin 3 He+ 25 Mg reaction. In both reactions the dilepton (e + e - ) and photon decay yields were measured concurrently. An excess of counts in the e + e - spectrum, over the converted photon yield, is observed in the energy region above 15 MeV. An analyses is discussed whereby the observed excess counts are assumed to represent the isoscalar E0 strength in excited nuclear states. (orig.)

Unveiling hidden properties of young star clusters: differential reddening, star-formation spread, and binary fraction

Science.gov (United States)

Bonatto, C.; Lima, E. F.; Bica, E.

2012-04-01

simulated Hess diagrams. Conclusions: Even for low-mass star clusters, ASAmin is sensitive to the values of cluster mass, age, distance modulus, star-formation spread, foreground and differential reddening, and to a lesser degree, binary fraction. Compared with simpler approaches, including binaries, a decaying star-formation rate, and a normally distributed differential reddening appears to yield more constrained parameters, especially the mass, age, and distance from the Sun. A robust determination of cluster parameters may have a positive impact on many fields. For instance, age, mass, and binary fraction are important for establishing the dynamical state of a cluster or for deriving a more precise star-formation rate in the Galaxy.

Formation and Evolution of X-ray Binaries

Science.gov (United States)

Shao, Y.

2017-07-01

X-ray binaries are a class of binary systems, in which the accretor is a compact star (i.e., black hole, neutron star, or white dwarf). They are one of the most important objects in the universe, which can be used to study not only binary evolution but also accretion disks and compact stars. Statistical investigations of these binaries help to understand the formation and evolution of galaxies, and sometimes provide useful constraints on the cosmological models. The goal of this thesis is to investigate the formation and evolution processes of X-ray binaries including Be/X-ray binaries, low-mass X-ray binaries (LMXBs), ultraluminous X-ray sources (ULXs), and cataclysmic variables. In Chapter 1 we give a brief review on the basic knowledge of the binary evolution. In Chapter 2 we discuss the formation of Be stars through binary interaction. In this chapter we investigate the formation of Be stars resulting from mass transfer in binaries in the Galaxy. Using binary evolution and population synthesis calculations, we find that in Be/neutron star binaries the Be stars have a lower limit of mass ˜ 8 M⊙ if they are formed by a stable (i.e., without the occurrence of common envelope evolution) and nonconservative mass transfer. We demonstrate that the isolated Be stars may originate from both mergers of two main-sequence stars and disrupted Be binaries during the supernova explosions of the primary stars, but mergers seem to play a much more important role. Finally the fraction of Be stars produced by binary interactions in all B type stars can be as high as ˜ 13%-30% , implying that most of Be stars may result from binary interaction. In Chapter 3 we show the evolution of intermediate- and low-mass X-ray binaries (I/LMXBs) and the formation of millisecond pulsars. Comparing the calculated results with the observations of binary radio pulsars, we report the following results: (1) The allowed parameter space for forming binary pulsars in the initial orbital period

First simultaneous measurement of fission and gamma probabilities of 237U and 239Np via surrogate reactions

Directory of Open Access Journals (Sweden)

Marini P.

2016-01-01

Full Text Available Fission and gamma decay probabilities of 237U and 239Np have been measured, for the first time simultaneously in dedicated experiments, via the surrogate reactions 238U(3He, 4He and 238U(3He,d, respectively. While a good agreement between our data and neutron-induced data is found for fission probabilities, gamma decay probabilities are several times higher than the corresponding neutron-induced data for each studied nucleus. We study the role of the different spin distributions populated in the surrogate and neutron-induced reactions. The compound nucleus spin distribution populated in the surrogate reaction is extracted from the measured gamma-decay probabilities, and used as input parameter in the statistical model to predict fission probabilities to be compared to our data. A strong disagreement between our data and the prediction is obtained. Preliminary results from an additional dedicated experiment confirm the observed discrepancies, indicating the need of a better understanding of the formation and decay processes of the compound nucleus.

Modelling binary data

CERN Document Server

Collett, David

2002-01-01

INTRODUCTION Some Examples The Scope of this Book Use of Statistical Software STATISTICAL INFERENCE FOR BINARY DATA The Binomial Distribution Inference about the Success Probability Comparison of Two Proportions Comparison of Two or More Proportions MODELS FOR BINARY AND BINOMIAL DATA Statistical Modelling Linear Models Methods of Estimation Fitting Linear Models to Binomial Data Models for Binomial Response Data The Linear Logistic Model Fitting the Linear Logistic Model to Binomial Data Goodness of Fit of a Linear Logistic Model Comparing Linear Logistic Models Linear Trend in Proportions Comparing Stimulus-Response Relationships Non-Convergence and Overfitting Some other Goodness of Fit Statistics Strategy for Model Selection Predicting a Binary Response Probability BIOASSAY AND SOME OTHER APPLICATIONS The Tolerance Distribution Estimating an Effective Dose Relative Potency Natural Response Non-Linear Logistic Regression Models Applications of the Complementary Log-Log Model MODEL CHECKING Definition of Re...

In-trap decay spectroscopy for {beta}{beta} decays

Energy Technology Data Exchange (ETDEWEB)

Brunner, Thomas

2011-01-18

The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in {beta}{beta} decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from {beta} decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and {beta} detection with almost no {beta}-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in {beta}{beta} decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in {beta}{beta} decays. These branches are typically of the order of 10{sup -5} and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating {beta} background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge

In-trap decay spectroscopy for ββ decays

International Nuclear Information System (INIS)

Brunner, Thomas

2011-01-01

The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in ββ decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from β decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and β detection with almost no β-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in ββ decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in ββ decays. These branches are typically of the order of 10 -5 and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating β background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge detectors, for the detection of X-rays, were

Decay tank

International Nuclear Information System (INIS)

Matsumura, Seiichi; Tagishi, Akinori; Sakata, Yuji; Kontani, Koji; Sudo, Yukio; Kaminaga, Masanori; Kameyama, Iwao; Ando, Koei; Ishiki, Masahiko.

1990-01-01

The present invention concerns an decay tank for decaying a radioactivity concentration of a fluid containing radioactive material. The inside of an decay tank body is partitioned by partitioning plates to form a flow channel. A porous plate is attached at the portion above the end of the partitioning plate, that is, a portion where the flow is just turned. A part of the porous plate has a slit-like opening on the side close to the partitioning plate, that is, the inner side of the flow at the turning portion thereof. Accordingly, the primary coolants passed through the pool type nuclear reactor and flown into the decay tank are flow caused to uniformly over the entire part of the tank without causing swirling. Since a distribution in a staying time is thus decreased, the effect of decaying 16 N as radioactive nuclides in the primary coolants is increased even in a limited volume of the tank. (I.N.)

Surface boiling - an obvious but like no other decay mode of highly excited atomic nuclei

International Nuclear Information System (INIS)

Toke, J.

2012-01-01

Essentials of a generalized compound nucleus model are introduced based on a concept of an open microcanonical ensemble which considers explicitly the role of the diffuse surface domain and of the thermal expansion of nuclear systems in the quest for maximum entropy. This obvious generalization offers a unique and universal thermodynamic framework for understanding the changes in the gross behavior of excited nuclear systems with increasing excitation energy and, specifically, the competition between different statistical decay modes, including classical evaporation and binary fission, but also the Coulomb fragmentation of excited systems into multiple fragments - the famed multifragmentation. Importantly, the formalism offers a natural explanation, in terms of boiling or spinodal vaporization, for the experimentally observed appearance of limiting excitation energy that can be thermalized by an exited nuclear system and the associated limiting temperature. It is shown that it is the thermal expansion that leads to volume boiling in an infinite matter and surface boiling in finite nuclei. The latter constitutes an important and universal, but hitherto unappreciated decay mode of highly excited nuclei, a mode here named surface spinodal vaporization. It is also shown that in iso-asymmetric systems, thermal expansion leads to what constitutes distillation - a decay mode here named distillative spinodal vaporization

Plasmon-driven sequential chemical reactions in an aqueous environment.

Science.gov (United States)

Zhang, Xin; Wang, Peijie; Zhang, Zhenglong; Fang, Yurui; Sun, Mengtao

2014-06-24

Plasmon-driven sequential chemical reactions were successfully realized in an aqueous environment. In an electrochemical environment, sequential chemical reactions were driven by an applied potential and laser irradiation. Furthermore, the rate of the chemical reaction was controlled via pH, which provides indirect evidence that the hot electrons generated from plasmon decay play an important role in plasmon-driven chemical reactions. In acidic conditions, the hot electrons were captured by the abundant H(+) in the aqueous environment, which prevented the chemical reaction. The developed plasmon-driven chemical reactions in an aqueous environment will significantly expand the applications of plasmon chemistry and may provide a promising avenue for green chemistry using plasmon catalysis in aqueous environments under irradiation by sunlight.

The {sup 152}Sm(p,n) reaction measurements in inverse kinematics

Energy Technology Data Exchange (ETDEWEB)

Pohl, Moritz [Goethe Univ. Frankfurt am Main (Germany); Collaboration: S405-Collaboration

2013-07-01

Under stellar conditions, low-lying excited states in nuclei are in thermal equilibrium with the ground state. If those excited states undergo β-decays with a higher rate than the ground state, the β-decay half-life of this nucleus is dominated by the excited state. The corresponding life-times are extremely difficult to measure directly on earth, since the de-excitation occurs mostly via internal transition. For the understanding of the processes occurring during a star collapse, simulations are a crucial tool. To provide a detailed view on those processes and the underlying theoretical models, also to test and improve the simulation networks, information extracted from experiments is needed. Unfortunately, some reactions can not be reproduced directly in laboratories. This applies for example to electron capture processes, which can lead to excited states energetically forbidden on earth. Those reactions are dominated by the so called Gamow-Teller distribution B(GT). If the β-decay occurs via the Gamow-Teller transition, charge exchange reactions allow to investigate the decay strength. In order to verify the method of measuring the B(GT) strength of unstable heavy nuclei via inverse kinematics, the reaction p({sup 152}Sm,{sup 152}Eu)n was used as a test case. This measurement allows to set constraints on the temperature dependent electron capture of {sup 152}Eu, which is an important s-process branching point. The s405 experiment took place at the R{sup 3}B/LAND setup at GSI. A newly developed Low Energy Neutron detector Array (LENA) was used to measure the recoil neutrons, which are emitted at large angles relatively to the incoming beam. To determine the detector response, a GEANT3 simulation was performed. Preliminary results are presented.

The decay of hot dysprosium nuclei

International Nuclear Information System (INIS)

Atac, A.; Rekstad, J.; Guttormsen, M.; Messelt, S.; Ramsoey, T.; Thorsteinsen, T.F.; Loevhoeiden, G.; Roedland, T.

1987-03-01

The γ-decay following the 162,163 Dy( 3 He,αxn) reactions with E 3 He =45 MeV has been studied. Non-statistical γ-radiation with energies of E γ ≅1 MeV and ≅2 MeV is found for various residual nuclei. The properties of these γ-ray bumps depend on the number of emitted neutrons and reveal an odd-even mass dependence. New techniques to extract average neutron energies as a function of excitation energy and of the number of emitted neutrons are employed. The deduced neutron energies are consistent with Fermi-gas model predictions

Formation and evolution of compact binaries

NARCIS (Netherlands)

Sluijs, Marcel Vincent van der

2006-01-01

In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

Do stellar clusters form fewer binaries? Using moderate separation binaries to distinguish between nature and nurture

Science.gov (United States)

Reiter, Megan

2017-08-01

Fewer wide-separation binaries are found in dense stellar clusters than in looser stellar associations. It is therefore unclear whether feedback in clusters prevents the formation of multiple systems or dynamical interactions destroy them. Measuring the prevalence of close, bound binary systems provide a key test to distinguish between these possibilities. Systems with separations of 10-50 AU will survive interactions in the cluster environment, and therefore are more representative of the natal population of multiple systems. By fitting a double-star PSF, we will identify visual binaries in the Orion Nebula with separations as small as 0.03. At the distance of Orion, this corresponds to a physical separation of 12 AU, effectively closing the observational gap in the binary separation distribution left between known visual and spectroscopic binaries (>65 AU or PhD thesis.

Development of a Monte Carlo code for the data analysis of the {sup 18}F(p,α){sup 15}O reaction at astrophysical energies

Energy Technology Data Exchange (ETDEWEB)

Caruso, A.; Cherubini, S.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Rapisarda, G.; Romano, S.; Sergi, ML. [Dipartimento di Fisica e Astronomia, Catania, Italy and INFN-Laboratori Nazionali del Sud, Catania (Italy); Crucillà, V. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Gulino, M. [Universitá di Enna KORE, Enna, Italy and INFN-Laboratori Nazionali del Sud, Catania (Italy); Kubono, S. [Riken, Wako, Tokyo, Japan and Center for Nuclear Study, The University of Tokyo (Japan); Yamaguchi, H.; Hayakawa, S.; Wakabayashi, Y. [Center for Nuclear Study, The University of Tokyo (Japan); Iwasa, N. [Department of Physics, Tohoku University, Sendai (Japan); Kato, S. [Department of Physics, Yamagata University, Yamagata (Japan); Komatsubara, T. [Rare Isotope Science Project, Institute for Basic Science, Yuseong-daero, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Teranishi, T. [Department of Physics, Kyushu University, Fukuoka (Japan); Coc, A. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Orsay (France); Hammache, F. [Institut de Physique Nucléaire, IN2P3, Orsay (France); and others

2015-02-24

Novae are astrophysical events (violent explosion) occurring in close binary systems consisting of a white dwarf and a main-sequence star or a star in a more advanced stage of evolution. They are called 'narrow systems' because the two components interact with each other: there is a process of mass exchange with resulting in the transfer of matter from the companion star to the white dwarf, leading to the formation of this last of the so-called accretion disk, rich mainly of hydrogen. Over time, more and more material accumulates until the pressure and the temperature reached are sufficient to trigger nuclear fusion reactions, rapidly converting a large part of the hydrogen into heavier elements. The products of 'hot hydrogen burning' are then placed in the interstellar medium as a result of violent explosions. Studies on the element abundances observed in these events can provide important information about the stages of evolution stellar. During the outbursts of novae some radioactive isotopes are synthesized: in particular, the decay of short-lived nuclei such as {sup 13}N and {sup 18}F with subsequent emission of gamma radiation energy below 511 keV. The gamma rays from products electron-positron annihilation of positrons emitted in the decay of {sup 18}F are the most abundant and the first observable as soon as the atmosphere of the nova starts to become transparent to gamma radiation. Hence the importance of the study of nuclear reactions that lead both to the formation and to the destruction of {sup 18}F. Among these, the {sup 18}F(p,α){sup 15}O reaction is one of the main channels of destruction. This reaction was then studied at energies of astrophysical interest. The experiment done at Riken, Japan, has as its objective the study of the {sup 18}F(p,α){sup 15}O reaction, using a beam of {sup 18}F produced at CRIB, to derive important information about the phenomenon of novae. In this paper we present the experimental technique and the

Origin of very-short orbital-period binary systems

International Nuclear Information System (INIS)

Miyaji, S.

1983-01-01

Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

Acidity decay of above-drainage underground mines in West Virginia.

Science.gov (United States)

Mack, B; McDonald, L M; Skousen, J

2010-01-01

Acidity of water from abandoned underground mines decreases over time, and the rate of decrease can help formulate remediation approaches and treatment system designs. The objective of this study was to determine an overall acidity decay rate for above-drainage underground mines in northern West Virginia from a large data set of mines that were closed 50 to 70 yr ago. Water quality data were obtained from 30 Upper Freeport and 7 Pittsburgh coal seam mines in 1968, 1980, 2000, and 2006, and acidity decay curves were calculated. The mean decay constant, k, for Upper Freeport mines was 2.73 x 10(-2) yr(-1), with a 95% confidence interval of +/- 0.0052, whereas the k value for Pittsburgh mines was not significantly different at 4.26 x 10(-2) yr(-1) +/- 0.017. Acidity from the T&T mine, which was closed 12 yr ago, showed a k value of 11.25 x 10(-2) yr(-1). This higher decay rate was likely due to initial flushing of accumulated metal salts on reaction surfaces in the mine, rapid changes in mine hydrology after closure, and treatment. Although each site showed a specific decay rate (varying from 0.04 x 10(-2) yr(-1) to 13.1 x 10(-2) yr(-1)), the decay constants of 2.7 x 10(-2) yr(-1) to 4.3 x 10(-2) yr(-1) are useful for predicting water quality trends and overall improvements across a wide spectrum of abandoned underground mines. We found first-order decay models improve long-term prediction of acidity declines from above-drainage mines compared with linear or percent annual decrease models. These predictions can help to select water treatment plans and evaluate costs for these treatments over time.

Separation in 5 Msun Binaries

Science.gov (United States)

Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

2013-01-01

Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

Astronomy of binary and multiple stars

International Nuclear Information System (INIS)

Tokovinin, A.A.

1984-01-01

Various types of binary stars and methods for their observation are described in a popular form. Some models of formation and evolution of binary and multiple star systems are presented. It is concluded that formation of binary and multiple stars is a regular stage in the process of star production

A ROSAT Survey of Contact Binary Stars

Science.gov (United States)

Geske, M. T.; Gettel, S. J.; McKay, T. A.

2006-01-01

Contact binary stars are common variable stars that are all believed to emit relatively large fluxes of X-rays. In this work we combine a large new sample of contact binary stars derived from the ROTSE-I telescope with X-ray data from the ROSAT All Sky Survey (RASS) to estimate the X-ray volume emissivity of contact binary stars in the Galaxy. We obtained X-ray fluxes for 140 contact binaries from the RASS, as well as two additional stars observed by the XMM-Newton observatory. From these data we confirm the emission of X-rays from all contact binary systems, with typical luminosities of approximately 1.0×1030 ergs s-1. Combining calculated luminosities with an estimated contact binary space density, we find that contact binaries do not have strong enough X-ray emission to account for a significant portion of the Galactic X-ray background.

GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

Energy Technology Data Exchange (ETDEWEB)

Holley-Bockelmann, Kelly [Vanderbilt University, Nashville, TN (United States); Khan, Fazeel Mahmood, E-mail: k.holley@vanderbilt.edu [Institute of Space Technology (IST), Islamabad (Pakistan)

2015-09-10

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

International Nuclear Information System (INIS)

Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

2015-01-01

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy

Hidden slow pulsars in binaries

Science.gov (United States)

Tavani, Marco; Brookshaw, Leigh

1993-01-01

The recent discovery of the binary containing the slow pulsar PSR 1718-19 orbiting around a low-mass companion star adds new light on the characteristics of binary pulsars. The properties of the radio eclipses of PSR 1718-19 are the most striking observational characteristics of this system. The surface of the companion star produces a mass outflow which leaves only a small 'window' in orbital phase for the detection of PSR 1718-19 around 400 MHz. At this observing frequency, PSR 1718-19 is clearly observable only for about 1 hr out of the total 6.2 hr orbital period. The aim of this Letter is twofold: (1) to model the hydrodynamical behavior of the eclipsing material from the companion star of PSR 1718-19 and (2) to argue that a population of binary slow pulsars might have escaped detection in pulsar surveys carried out at 400 MHz. The possible existence of a population of partially or totally hidden slow pulsars in binaries will have a strong impact on current theories of binary evolution of neutron stars.

Hadronic decay of late-decaying particles and big-bang nucleosynthesis

Energy Technology Data Exchange (ETDEWEB)

Kawasaki, Masahiro [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Tokyo 113-0033 (Japan)]. E-mail: masahiro_kawasaki@mac.com; Kohri, Kazunori [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Moroi, Takeo [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

2005-10-06

We study the big-bang nucleosynthesis (BBN) scenario with late-decaying exotic particles with lifetime longer than {approx}1 s. With a late-decaying particle in the early universe, predictions of the standard BBN scenario can be significantly altered. Therefore, we derive constraints on its primordial abundance. We pay particular attention to hadronic decay modes of such particles. We see that the non-thermal production process of D, {sup 3}He and {sup 6}Li provides a stringent upper bound on the primordial abundance of late-decaying particles with hadronic branching ratio.

The beta decay asymmetry parameter of 35Ar

International Nuclear Information System (INIS)

Garnett, J.D.

1987-11-01

The beta decay asymmetry parameter for 35 Ar = 35 Cl + e + + nu/sub e/ has been remeasured in order to resolve a long standing puzzle. Previous asymmetry measurements, when combined with the comparative half-life, yield a value for the vector coupling constant, G/sub v/, that is in serious disagreement with the accepted value. We produced polarized 35 Ar by a (p,n) reaction on 35 Cl using the polarized proton beam provided by Lawrence Berkeley Laboratory's 88-Inch Cyclotron. The polarization of the 35 Ar was determined by measuring the asymmetry of the positrons produced in 35 Ar decay to the first excited state in 35 Cl (branching ratio = 1.3%) in coincidence with a 1219.4 keV gamma ray. Our result, A 0 = 0.49 +- 0.10, combined with the comparative half-life yields a value for G/sub v/ in agreement with the accepted value

The role of water in food quality decay

Directory of Open Access Journals (Sweden)

Laura Piazza

2006-07-01

Full Text Available The impact of water on food thermodynamics and physics, and therefore on its quality, is more important than any other food chemical component. When fundamentals of chemical kinetics apply, the rates of the reactions that are responsible of food quality decay can be described as a function of food composition and of other external elements interacting with foods. Among them, water activity and water content have been widely used to determine the role of water in the kinetic reactions of deterioration. Recently, researchers have found limitations in using the water activity parameter. According to them, the role of water in foods can be better described by evaluating the role in the stability of the quality attributes of the non-equilibrium states of amorphous food products. Following this approach, the dynamics of the changes are described in kinetics terms and can be efficiently better predicted by the glass transition temperature more than by the water activity. The glass transition, which is a second order transition in amorphous materials from the glassy to the rubbery state, is primarily dependent on water which is a plasticizer and is responsible for the physical state of multiphase systems (as foods are together with the temperature. The subject of the role of water in the decay of food quality will be presented in this paper according to the principles of food material science.

Perceptual biases for rhythm: The Mismatch Negativity latency indexes the privileged status of binary vs non-binary interval ratios.

Science.gov (United States)

Pablos Martin, X; Deltenre, P; Hoonhorst, I; Markessis, E; Rossion, B; Colin, C

2007-12-01

Rhythm perception appears to be non-linear as human subjects are better at discriminating, categorizing and reproducing rhythms containing binary vs non-binary (e.a. 1:2 vs 1:3) as well as metrical vs non-metrical (e.a. 1:2 vs 1:2.5) interval ratios. This study examined the representation of binary and non-binary interval ratios within the sensory memory, thus yielding a truly sensory, pre-motor, attention-independent neural representation of rhythmical intervals. Five interval ratios, one binary, flanked by four non-binary ones, were compared on the basis of the MMN they evoked when contrasted against a common standard interval. For all five intervals, the larger the contrast was, the larger the MMN amplitude was. The binary interval evoked a significantly much shorter (by at least 23 ms) MMN latency than the other intervals, whereas no latency difference was observed between the four non-binary intervals. These results show that the privileged perceptual status of binary rhythmical intervals is already present in the sensory representations found in echoic memory at an early, automatic, pre-perceptual and pre-motor level. MMN latency can be used to study rhythm perception at a truly sensory level, without any contribution from the motor system.

SECULAR EVOLUTION OF BINARIES NEAR MASSIVE BLACK HOLES: FORMATION OF COMPACT BINARIES, MERGER/COLLISION PRODUCTS AND G2-LIKE OBJECTS

International Nuclear Information System (INIS)

Prodan, Snezana; Antonini, Fabio; Perets, Hagai B.

2015-01-01

Here we discuss the evolution of binaries around massive black holes (MBHs) in nuclear stellar clusters. We focus on their secular evolution due to the perturbation by the MBHs, while simplistically accounting for their collisional evolution. Binaries with highly inclined orbits with respect to their orbits around MBHs are strongly affected by secular processes, which periodically change their eccentricities and inclinations (e.g., Kozai-Lidov cycles). During periapsis approach, dissipative processes such as tidal friction may become highly efficient, and may lead to shrinkage of a binary orbit and even to its merger. Binaries in this environment can therefore significantly change their orbital evolution due to the MBH third-body perturbative effects. Such orbital evolution may impinge on their later stellar evolution. Here we follow the secular dynamics of such binaries and its coupling to tidal evolution, as well as the stellar evolution of such binaries on longer timescales. We find that stellar binaries in the central parts of nuclear stellar clusters (NSCs) are highly likely to evolve into eccentric and/or short-period binaries, and become strongly interacting binaries either on the main sequence (at which point they may even merge), or through their later binary stellar evolution. The central parts of NSCs therefore catalyze the formation and evolution of strongly interacting binaries, and lead to the enhanced formation of blue stragglers, X-ray binaries, gravitational wave sources, and possible supernova progenitors. Induced mergers/collisions may also lead to the formation of G2-like cloud-like objects such as the one recently observed in the Galactic center

Radioactive decay of sup(91m)Nb

Energy Technology Data Exchange (ETDEWEB)

Lakshminarayana, V.; Venkataratnam, S.; Rao, B.V.T.; Narasimham, K.L.; Chintalapudi, S.N.

1987-08-01

The radioactive decay of sup(91m)Nb, produced by the reaction /sup 89/Y(..cap alpha.., 2n), is studied using Ge(Li), HPGe and Si(Li) detectors. The K-conversion coefficient, ..cap alpha..sub(K), of the 104.5 keV transition is determined accurately, for the first time, from the Nb Ksub(..cap alpha..) x-ray and 104.5 keV gamma-ray intensities. The experimental value of ..cap alpha..sub(K) thus determined is 115(5), in agreement with the value expected for an M4 transition.

A brief review of ultra-rare alpha decay detection technique

International Nuclear Information System (INIS)

Tsyganov, Yu.S.

2006-01-01

Three approaches to the measurement of rare alpha decaying products produced in heavy-ion induced nuclear reactions are described. One is based on a chemical extraction and following deposition of the nuclides under investigation onto the surface of the detector, whereas the second one is associated with long-lived products implanted into silicon detectors by using the electromagnetic separation technique. The third approach relates with an application of real-time mode detection of correlated energy-time-position recoil-alpha sequences from 48 Ca-induced nuclear reactions with actinide targets, like 242,244 Pu, 245,248 Cm, 243 Am, and 249 Cf. Namely with this technique it has became possible to provide a radical suppression of backgrounds in the full fusion (3-5n) reactions aimed at the synthesis of superheavy elements with Z = 113-118

Galactic binaries with eLISA

OpenAIRE

Nelemans, G.

2013-01-01

I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

Description of new element Z=113 and its α-decay chain

International Nuclear Information System (INIS)

Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou; National Laboratory of Heavy Ion Accelerator, Lanzhou

2005-01-01

RIKEN has produced a new element Z=113 by cold-fusion reaction. Here we systematically study the new nuclide 278 113 and its α-Decay chain using deformed relativistic mean-field theory with three sets of force parameters, TMA, NL-Z2 and NL3. The results are compared with those of the Skyrme-Hartree-Fock model, Moeller et al and also with the new experimental data. The experimental decay energies are well reproduced with RMF. This not only shows the validity of self-consistent field theoretical model in researching the ground state properties of superheavy nuclei, but also shows that prolate deformation is important for the ground state of these nuclei. (authors)

Rare decays and CP asymmetries in charged B decays

International Nuclear Information System (INIS)

Deshpande, N.G.

1991-01-01

The theory of loop induced rare decays and the rate asymmetry due to CP violation in charged B Decays in reviewed. After considering b → sγ and b → se + e - decays, the asymmetries for pure penguin process are estimated first. A larger asymmetry can result in those modes where a tree diagram and a penguin diagram interfere, however these estimates are necessarily model dependent. Estimates of Cabbibo suppressed penguins are also considered

The production of high energy neutrons by secondary reactions

International Nuclear Information System (INIS)

Nieschmidt, E.B.; Roney, T.J.; Staples, D.R.; Harmon, J.F.; Burkhart, J.H.

1994-01-01

The potential of using binary reactions in targets containing Be is discussed. Data are presented from the use of Be and BeF 2 targets bombarded with 1.5, 1.7, 1.8 and 1.9 MeV protons. Neutron production is enhanced by the presence of the F by factors of ∼4

a Search for Nucleon Decay with Multiple Muon Decays

Science.gov (United States)

Phillips, Thomas James

A search was made for nucleon decays which result in multiple delayed muon decays using the HPW (Harvard -Purdue-Wisconsin) water Cerenkov detector. The HPW detector consists of 680 metric tons of purified water instrumented with 704 five-inch photomultiplier tubes. The phototubes are situated on a volume array with a lattice spacing of approximately one meter, and the inside walls of the detector are lined with mirrors. This combination of mirrors and a volume array of phototubes gives the HPW detector a low trigger energy threshold and a high muon decay detection efficiency. The detector is surrounded by wire chambers to provide an active shield, and is located at a depth of 1500 meters-of-water-equivalent in the Silver King Mine in Park City, Utah. The entire HPW data set, consisting of 17.2 million events collec- ted during 282 live days between May 1983 and October 1984, was analyzed. No contained events with multiple muon decays were found in a 180 ton fiducial volume. This is consistent with the background rate from neutrino interactions, which is expected to be 0.7 (+OR-) 0.2 events. The calculated lower lifetime limit for the decay mode p (--->) (mu)('+)(mu)('+)(mu)('-) is: (tau)/B.R. = 1 x 10('31) years (90% C.L.). Limits are calculated for ten other proton decay modes and five bound neutron decay modes, most of which are around 4 x 10('30) years (90% C.L.). No previous studies have reported results from direct searches for eight of these modes.