Beryllium Nuclei Research Articles

Beryllium Isotopes in the PAMELA Experiment

Analysis of the isotopic composition of nuclei in galactic cosmic rays (GCR) in the orbital experiment of the PAMELA collaboration makes it possible to study the problems of the origin and propagation of cosmic rays in the Galaxy. The data of the PAMELA magnetic spectrometer, due to their high statistical and methodological accuracy, ensured significant progress in the study of the isotopic composition of light nuclei from H to Be in GCR in the energy range ~ 0.1-1 GeV/nucleon and for the first time made it possible to estimate the contribution to GCR of Local Interstellar Sources (LIS) from close (∼ 100 pc) of recent (~ million years) supernova explosions. To date, the isotopic composition of beryllium nuclei in GCR has been measured only for 7Be./9Be, 10Be/9Be ratios in the energy range of ∼ 100 MeV/nucleon in the space experiments IMP 7/8, Voyager, Ulysses, ACE/CRIS and for 10Be/9Be in balloon experiment with a superconducting magnet ISOMAX-98 for energies 0.2-1.0 and 1.1-2.0 GeV/nucleon. In this work, using flight data PAMELA 2006-2014, on the rigidity of the detected nuclei and their velocity (time-of-flight analysis and ionization losses in the multilayer calorimeter of the instrument), a new analysis of the isotopic composition of beryllium nuclei in the energy range of ~ 0.1-1.4 GeV/nucleon has been carried out. The results of isotopic analysis of beryllium nuclei in GCR (spectra 7Be, 9Be, 10Be and 7Be/9Be, 10Be/9Be - ratio depending on the rigidity and energy of nuclei) in comparison with the existing measurement and calculation data will be presented.

Monte Carlo modeling of production of three alpha-particles in low energy n +12C interactions

To describe [Formula: see text] interactions with production of three [Formula: see text]-particles at incident neutron kinetic energy of 14 MeV in a nuclear (photo) emulsion, a Monte Carlo model is proposed for four channels of decay of an excited carbon-12 nucleus into three [Formula: see text]-particles. The Monte Carlo calculation results describe well the experimental data on the distribution of the angle between the three-dimensional momenta of all pairs of [Formula: see text]-particles in a collision event, on the distribution of the angle between the projections of the momentum vectors of all pairs of [Formula: see text]-particles in collision event on each of the coordinate planes, on the distribution of the sum of the kinetic energies of all pairs of [Formula: see text]-particles in a collision event, and the distribution of projections of the momenta of [Formula: see text]-particles on the coordinate planes. The best agreement of the Monte Carlo model results with the experimental data is achieved if the direct decay [Formula: see text] and decay through the formation of an intermediate beryllium nucleus [Formula: see text] are generated with equal probabilities, while the excitation energies of 3.04 MeV, 1.04 MeV, and 0.1 MeV for the beryllium nucleus are generated with relative weights of 75%, 15%, and 10%, respectively.

Atomki anomaly in gauged U(1)R symmetric model

The Atomki collaboration has reported that unexpected excesses have been observed in the rare decays of Beryllium nucleus. It is claimed that such excesses can suggest the existence of a new boson, called X, with the mass of about 17 MeV. To solve the Atomki anomaly, we consider a model with gauged U(1)R symmetry and identify the new gauge boson with the X boson. We also introduce two SU(2) doublet Higgs bosons and one singlet Higgs boson, and discuss a very stringent constraint from neutrino-electron scattering. It is found that the U(1)R charges of the doublet scalars are determined to evade the constraint. In the end, we find the parameter region in which the Atomki signal and all experimental constraints can be simultaneously satisfied.

Data for Beryllium–Hydrogen Charge Exchange in One and Two Centres Models, Relevant for Tokamak Plasmas

Data on the cross section and kinetic rate of charge exchange (CX) between the bare beryllium nucleus, the ion Be(+4) and the neutral hydrogen atom are of great interest for visible-range high-resolution spectroscopy in the ITER tokamak because beryllium is intended as the material for the first wall in the main chamber. Here an analysis of available data is presented, and the data needs are formulated. Besides the active probe signal produced by the CX of the diagnostic hydrogen neutral beam with impurity ions in plasma, a passive signal produced by the CX of impurity ions with cold edge plasma is also important, as it shows in observation data from the JET (Joint European Torus) tokamak with an ITER-like beryllium wall. Data in the range of a few eV/amu to ~100 eV/amu (amu stands for the atomic mass unit) needed for simulations of level populations for principal and orbital quantum numbers in the emitting beryllium ions Be(+3) can be obtained with the help of two-dimensional kinetic codes. The lack of literature data, especially for data resolved in orbital quantum numbers, has instigated us to make numerical calculations with the ARSENY code. A comparison of the results obtained for the one-centre Coulomb problem using an analytic approach and for the two-centre problem using numerical simulations is presented.

Elastic and Inelastic Electron-Nucleus Scattering Form Factors for Be9 Nucleus

The computations of the elastic and inelastic Coulomb form factors for the electron-nucleus scattering of Beryllium nucleus Be9 have performed with Core Polarization (CP) effects including the realistic Michigan sum of Three Range Yukawa (M3Y) Interaction, and the other residual interaction which is Modified Surface Delta Interaction (MSDI). In addition to mean square root charge density and charge radii for the ground state. The perturbation theory was adopted to compute the Core Polarization by using the Harmonic Oscillators (HO) potential to calculate single-particle radial wave functions.
 In the comparison between the theoretical calculations of Coulomb form factors by (MSDI) interaction, realistic (M3Y) interaction, and the experimental results that measured before, it noticed that the Coulomb form factors for the (M3Y) interaction gave a reasonable depiction of the measured data.

Li and Be Isotopes in the PAMELA Experiment from Flight Data for 2006–2014

The results are presented from measuring the isotopic composition of lithium and beryllium nuclei in galactic cosmic rays with energies of up to ~1 GeV/nucleon, obtained with the best statistical and methodical reliability in the PAMELA orbital experiment in 2006–2014. The time-of-flight analysis of nuclei in a scintillation telescope and an analysis of the distributions of ionization losses of the nuclei in the tracker and multilayer calorimeter of the PAMELA magnetic spectrometer with the rigidity known from measuring the path in the magnet gap are used. The analysis uses the results from GEANT4 modeling of the distribution of the time of flight and the ionization losses of nuclear isotopes in the calorimeter with a rigidity step of 0.2 GV, which are in good agreement with the corresponding experimental distributions. Nuclear charges are determined from the scintillation telescope data of the PAMELA magnetic spectrometer. The spectra of 6Li, 7Li, 7Be, 9Be, and 10Be isotopes are obtained, depending on their rigidity, energy, and ratios. The results from measurements are compared to existing experimental and calculated data. Based on new data on the isotopic composition of Li and Be nuclei, the contribution from local light-nucleus sources from recent (~1 million years) nearby (~100 ps) supernova explosions to the intensity of galactic cosmic rays is estimated for the first time.

Particle-Hole Cluster Shell Model States in 8Be, a Challenge for Ab-Intio Nuclear Theories

We propose the first application of the Cluster Shell Model (CSM) of Della Rocca and Iachello to particle-hole (p-h) states in 8Be. We demonstrate a few essential features of the CSM in 8Be: 1) All predicted p-h states of the CSM, and only the predicted p-h states, are observed near thresholds and up to 19.5 MeV in 8Be. 2) The states are observed in the predicted order, with positive parity states below negative parity states. 3) Some of the p-h states are already known to have the rotational structure predicted for the deformed p-h states. 4) The rotational structures observed at high excitations in the p-h bands in 8Be, resemble the ground state bands of 8Be, 9Be and 9B, with similar moment of inertia. Based on these observations we contemplate new measurements of the spectroscopy of 8Be at energies above 19.5 MeV, where our knowledge of states in 8Be is scarce. We examine the observed B(M1)s and B(E2)s in these nuclei and contemplate a measurement of the B(E2) of the isobaric Analog transition in 8B. We discuss the observed rotational structure in 8Be as a challenge to ab-initio calculations that searched for “emerging rotational structures at high excitations" in beryllium nuclei, and reveal rotational structure at high excitations in 10Be and 12Be but not in 8Be.

The mechanism of cumulative proton production in the collision of 12C and 9Be nuclei at the energies of 0.6, 0.95 and 2 GeV/nucleon

The collision of carbon nuclei with beryllium nuclei was simulated in the framework of Liège Intranuclear-Cascade model at the initial kinetic energies of the carbon nuclei 0.6, 0.95, 2.0 GeV/nucleon. The invariant cross sections of inclusive proton production at an angle of 3.5° are obtained. It is shown that the dependence of experimental invariant cross sections of proton production on the cumulative variable x in the range 0.9 < x < 2.4 can be explained on the basis of Fermi motion of nucleons in the nuclei, multiple scattering processes and delta resonance formation. A comparison was made with results obtained within the framework of the quark cluster model and experimental data.

Cumulative Protons in Collisions between Carbon and Beryllium Nuclei at Energies of 0.60, 0.95, and 2.0 GeV/nucleon

Collisions between carbon and beryllium nuclei at initial kinetic energies of carbon nuclei of 0.6, 0.95, and 2.0 GeV/nucleon have been simulated within the Liege intranuclear cascade model. Invariant proton production cross sections at an angle of 3.5° have been determined. It has been shown that the dependence of experimental invariant proton production cross sections on the cumulative variable can be explained in terms of Fermi processes of motion of nucleons in a nucleus, multiple scattering, and production of delta resonances. Results of simulation have been compared to experimental data and results obtained within the quark cluster model.

Spectra of double-cumulative photons in the central rapidity region at high transverse momenta

The spectra of photons produced in the interaction between carbon ions of kinetic energy 2.0 and 3.2 GeV per nucleon and beryllium nuclei were measured at the FLINT facility by means of electromagnetic calorimeters that is deployed at the accelerator of the Institute for Theoretical and Experimental Physics (ITEP, Moscow). The spectra in question were measured in the central rapidity region (at angles between 35° and 73° in the laboratory frame) at photon energies of 1 to 3 GeV by using a cumulative-photon trigger. An analysis of the data obtained in this way reveals that the interaction of multinucleon fluctuation in the projectile nucleus with a multinucleon fluctuation in the target nucleus is a dominant process that leads to photon production in the measured region of angles and momenta. As a development of the generally accepted terminology, an interaction of this type may be called a double cumulative interaction.

Pair potential of liquid metallic Be from electron theory compared and contrasted with recent ab initio work on the free-space beryllium dimer

Two decades ago, Perrot and March [F. Perrot and N.H. March, Phys. Rev. A. 41, 4521 (1990)] used electron theory to derive an oscillatory pair potential between the beryllium nuclei in liquid metal beryllium. They predict a first minimum at 2.1 Å, followed by a larger repulsive hump at 2.8 Å. Here, we compare and contrast this result for liquid beryllium with the recent ab initio work by Koput and the present quantum Monte Carlo (QMC) calculation on the beryllium dimer in free space. Koput situates the minimum in the potential curve for the free-space dimer at 2.4 Å and it is quite similar in depth to that for liquid metallic beryllium. Our QMC curve is similar, with the minimum at 2.33 Å. They are tabulated in this letter.

Effect of spin-orbit nuclear charge density corrections due to the anomalous magnetic moment on halonuclei

In this paper we consider the contribution of the anomalous magnetic moments of protons and neutrons to the nuclear charge density. We show that the spin-orbit contribution to the mean-square charge radius, which has been neglected in recent nuclear calculations, can be important in light halonuclei. We estimate the size of the effect in helium, lithium, and beryllium nuclei. It is found that the spin-orbit contribution represents a $~2%$ correction to the charge density at the center of the $^{7}\mathrm{Be}$ nucleus. We derive a simple expression for the correction to the mean-square charge radius due to the spin-orbit term and find that in light halonuclei it may be larger than the Darwin-Foldy term and comparable to finite size corrections. A comparison of experimental and theoretical mean-square radii including the spin-orbit contribution is presented.

Cross-sections of large-angle hadron production in proton– and pion–nucleus interactions II: beryllium nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons and charged pions, in the interactions with a 5% λ abs thick stationary beryllium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20° <θ<125°.

Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions I: beryllium nuclei and beam momenta of +8.9 GeV/c and −8.0 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons, deuterons, and charged pions and kaons, in the interactions with a 5% λ abs thick stationary beryllium target, of a +8.9 GeV/c proton and pion beam, and a −8.0 GeV/c pion beam. Results are given for secondary particles with production angles 20○<θ<125○.

Comparison of Geant4 hadron generation with data from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions and −8.0 GeV/c pions

Hadron generation in the Geant4 simulation tool kit is compared with inclusive spectra of secondary protons and pions from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of −8.0 GeV/c pions. The data were taken in 2002 at the CERN Proton Synchrotron with the HARP spectrometer. We report on significant disagreements between data and Monte Carlo simulation especially in the polar-angle distributions of secondary protons and pions.

Determination of the nuclear vertex constants for the 7Be ↔ 3He4He vertex using theN/D equations and calculation of the astrophysical S factor for the 4He(3He, γ)7Be reaction

N/D equations taking into account the Coulomb interaction effects are used to consider the phase analysis data on 3He4He scattering and determine the nuclear vertex constants for the 7Be ↔ 3He4He vertex, where the beryllium nucleus is in the ground (3/2−) or first excited (1/2−) states. Information about the asymptotic normalization coefficients of the wave functions of the 7Be nucleus in the noted states is derived. The data obtained are used to calculate the astrophysical S factor for the 4He(3He, γ)7Be reaction.

Measurement of the tensor analyzing power A yy in the inelastic scattering of 4.5-GeV/c deuterons on beryllium at an angle of 80 mrad

The tensor analyzing power Ayy and the vector analyzing power Ay for the inelastic scattering of 4.5-GeV/c deuterons on beryllium nuclei at angle of about 80 mrad are measured in the vicinity of baryon-resonance excitation. These new data, presented as a function of t, comply well with the results of previous 4.5-, 5.5-, and 9-GeV/c measurements at zero angle in overlapping regions of t; all available data are described by a unified dependence on |t| upto about 0.9 (GeV/c)2. The experimental results are compared with the results of calculations performed within the multiple-scattering model and the model involving omega-meson exchange in the t channel.

Beryllium(II) complexes of the Kläui tripodal ligand cyclopentadienyltris(diethylphosphito-p)cobaltate(-).

The interactions of the beryllium(II) ion with the cyclopentadienyltris(diethylphosphito-P)cobaltate monoanion, L(-), have been investigated, in aqueous solution, by synthetic methods, potentiometry, ESMS, and (1)H, (31)P, and (9)Be NMR spectroscopy. L(-) has been found able to displace either two or three water molecules in the beryllium(II) coordination sphere, to form mononuclear, dinuclear, and trinuclear derivatives, in which the metal ion is pseudotetrahedrally coordinated. The species [BeL(H(2)O)](+) and [Be(2)L(2)(mu-OH)](+) have been identified in solution while complexes of formula BeL(2) and [Be(3)L(4)](ClO(4))(2) have been isolated as solid materials. The species [BeL(OPPh(2))](+), closely related to [BeL(H(2)O)](+), has been characterized in acetone solution and isolated as tetraphenylborate salt. The structure of the unusual trimeric complex [Be(3)L(4)](2+) has been elucidated by an unprecedented 2D (9)Be-(31)P NMR correlation spectrum showing the presence of a single central beryllium nucleus and two equivalent terminal beryllium nuclei. The three beryllium centers are held together by four cobaltate ligands, which display two different bonding modes: two ligands are terminally linked with all the three oxygen donors to one terminal beryllium, and the other two bridge two metal centers, sharing the oxygen donors between central and terminal beryllium atoms.

Searches for a double-color-exchange transition in pion-proton interactions at 43 GeV/c in beryllium nuclei

Searches for a double-color-exchange transition in pion-proton interactions at 43 GeV/c in beryllium nuclei

Small-energy three-body systems. V. threshold laws when Wannier theory fails

We investigate cases of Coulombic systems near the break-up threshold for which the Wannier model holds, but not Wannier theory. Making use of the classical trajectory method, we derive threshold laws for a model system of fractional charge (Z= 1/4 au) nucleus and electrons, and a real (though perhaps impractical) system of two beryllium nuclei and an antiproton. For the first system we find the threshold law of the form exp(- lambda / square root E), where E is the total energy, and for the second one a number of characteristic features above the classical threshold have been obtained. Finally we investigate numerically a realistic case of an electron and two beryllium nuclei and discuss some general features of the ionization probability above the classical threshold.