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The recently observed ferroelectricity in thin films of pure and doped Hafnium oxide (HfO2) has initiated a sustaining effort to stabilize its ferroelectric phase which is the polar orthorhombic (o) phase with space group Pca21. This polar o-phase of the oxide does not appear in its phase transition sequence and is also not thought to be stabilized in bulk oxide. Here, we report the stabilization of three o-phases of this oxide in bulk with space groups Pbca, Pca21 and Pbcm in presence of Yttrium (Y) dopant. For inducing o-phase, 10 at% of Y-dopant has been used and temperature mediated phase transformation from monoclinic (m) to o-phase has been observed. The third o-phase with space group Pbcm could be stabilized for the first time in bulk oxide by Y-dopant. All the o-phases in presence of m-phase could be identified by Time Differential Perturbed γ-γ Angular Correlation (TDPAC) Spectroscopy. The TDPAC parameters assigned to Pbcm phase confirm the theoretical modelization for the phase performed by Wien2K calculation based on Density Functional Theory (DFT). The present work reports the possibility of stabilizing different o-phases including polar one and shows the widening of scope of this oxide for future ferroelectric applications.

Ferromagnetism in Hf6Co23 intermetallic alloy at room temperature has been confirmed from perturbed angular correlation measurements using 181Hf probe. The strength of hyperfine magnetic field at room temperature for this intermetallic compound has been found to be B hf = 2.5 ( 2 ) T while the earlier report of hyperfine magnetic field in Hf6Co23 has discrepancy. The hyperfine magnetic field at Ta impurity site has also been calculated by density functional theory and the result is found to be B hf = - 4.964 T (at 0 K). This value is closer to the present experimental value measured at 298 K. The compound Hf6Co23 has been found to decompose reversibly to Hf2Co7 at 473 K. Ferromagnetism in this material has been found up to 423 K and its Curie temperature is, therefore, set as T C > 423 K. From recent measurements by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, electron probe microanalysis and differential scanning calorimetry, Hf6Co23 was reported to be stable in a wide range of temperature and there was no phase existence of Hf2Co7 while the previous reported phase diagram showed a decomposition of Hf6Co23 to Hf2Co7 at a higher temperature.

In this paper we investigated the effects of Fe -doping of the anatase TiO 2 (1 0 1) surface on the crystal structure, electronic and optical properties, and impurity formation energy by means of density functional theory (DFT). The calculations were performed by the SIESTA DFT code and were carried out by using Troullier-Martins pseudopotentials for the 12-electron valence configuration ( 3 s 2 3 p 6 3 d 2 4 s 2 ) of Ti atom, 6-electron valence configuration ( 2 s 2 2 p 4 ) of O atom and 8-electron valence configuration ( 3 d 6 4 s 2 ) of Fe atom. We used a double- ζ basis set including polarization functions. All calculations were spin-polarized. The mechanism of narrowing the band gap and increasing the photocatalytic activity in the visible light region, of the doped TiO 2 is discussed by investigating the density of state. The band gap decreases as the concentration of the dopant increases. The Partial Density of States (PDOS) is not the same in the case of spin-up state or spin-down state. Enhanced optical absorption, for light polarized in the z direction (parallel to the surface normal) is clearly observed for Fe doped as compared to the pure anatase TiO 2 and the optical absorption is found to increase with the increase in the Fe concentration. The DFT results indicate that the source of the increasing photocatalytic activity in the visible light region of the Fe doped material is due to the introduction of additional electronic states within the band gap. Since the Fe atoms are more stable in Ti substitutional lattice positions for the entire range of Fermi energy E F over the band gap, only this substitutional position is considered. We hope that our results will highlight a route to improved electronic and optical properties of anatase TiO 2 for industrial applications.

In this paper we studied the effects of the concentration of W as a doped atom on the V lattice site on the electronic and optical properties of tetragonal zircon-type B i V O 4 structure. The calculations were performed by the first-principles density functional theory WIEN2k code. The doping strategy was targeting V atoms substituted by W atoms using the same lattice parameters as pure B i V O 4 structure. To avoid the self interaction of impurities, the supercell method was adopted ensuring a sufficient length between the impurities in all directions. For all considered concentrations, the optical properties in the visible light range of λ ≥ 550 n m are improved over the undoped B i V O 4 .

In pure HfO2, only P 2 1 / c monoclinic phase was known to exist from previous investigations and there is no report of orthorhombic phase in pure bulk HfO2 at ambient temperature and pressure. Present atomic scale measurements by perturbed angular correlation (PAC) spectroscopy, report two orthorhombic phases in pure bulk HfO2 at room temperature along with the most commonly observed monoclinic phase ( ∼ 80%). By comparing with the calculated results of density functional theory using full potential (linearized) augmented plane wave method (FP-LAPW), these two orthorhombic phases have been attributed to structures with space group Pbca and Pca 2 1 . The structures with space group Pca 2 1 and Pmn 2 1 are non-centrosymmetric and were found to be responsible for ferroelectricity in doped thin film HfO2. At room temperature, the site percentages for the Pca 2 1 and Pbca have been found to be ∼ 6% and ∼ 10%, respectively. At high temperatures of 973 and 1073 K, the Pca 2 1 phase was not found but, the Pbca orthorhombic phase was found to be present in the whole temperature range from 298 to 1073 K. The third orthorhombic phase Pmn 2 1 was not observed in bulk HfO2. Interestingly, In Gd doped (5 at%) HfO2, these two orthorhombic phases enhance more than the monoclinic phase. In Gd doped oxide, the P 2 1 / c monoclinic phase reduces to ∼ 24% while the site percentages for the two orthorhombic phases have been found to be ∼ 54% ( Pbca ) and ∼ 17% ( Pca 2 1 ).

Substitutionally doped Bi2 W 1 - x M x O6 ( M = Mo, Cr, Fe, Zn; x = 0.125, 0,25, 0.5) is investigated using the density functional theory (DFT). For all the investigated transition metal dopants, the optical properties in the visible light range are improved over the undoped Bi2WO6. Irrespective of concentration, the lattice relaxation around the dopants is constrained to the first coordination shell. Mo, Fe, and Cr introduce localized defect states in the band gap, contributing to band gap narrowing. The localized states are hybridized between the impurity d–bands and host W 5d–and O 2p–states. Zn facilitates the reduction of the band gap by inducing a shift of the states near the top of the valence band toward higher energies. Our results suggest that Zn doping on the W lattice site may improve the photocatalytic properties of Bi2WO6 more than the other dopants.

Intermetallic compound Zr 7 Ni 10 has been studied by perturbed angular correlation (PAC) spectroscopy to determine the electric field gradient and site occupation of Hf dopant in the compound. A mixture of phase components were found in this sample. The component with V zz = 6.6(1)× 10 21 V/m 2 and η = 0.71(1) at room temperature has been assigned to Zr 7 Ni 10 phase. In this sample, Zr 2 Ni 7 and Zr 8 Ni 21 phases were also found to be present along with Zr 7 Ni 10 . No phase transition is observed in the temperature range 77-1073 K in this sample. The electric field gradient (V zz ) for Zr 7 Ni 10 phase was found to decrease linearly with temperature. The phase components in Zr 7 Ni 10 have been determined also from X-ray powder diffraction (XRD) measurement. Theoretical calculations of EFG have been performed in Ta-doped Zr 7 Ni 10 using all electron full potential (linearized) augmented plane wave [FP-(L)APW] method, within the framework of the density functional theory (DFT) to compare the results with the values obtained from PAC measurements and to know the site preference of 181 Ta probe in the host matrix. This article is part of the Topical Collection on Proceedings of the International Conference on Hyperfine Interactions and their Applications (HYPERFINE 2019), Goa, India, 10-15 February 2019 Erratum: [http://dx.doi.org/10.1007/s10751-019-1613-8] Erratum 2: [http://dx.doi.org/10.1007/s10751-019-1644-1]

Crystalline phases formed in stoichiometric Zr$_9$Ni$_{11}$ and Hf$_9$Ni$_{11}$ have been studied by perturbed angular correlation (PAC) spectroscopy, XRD and TEM/SAED measurements. In Zr$_9$Ni$_{11}$, the phases Zr$_9$Ni$_{11}$ ($\sim$89\%) and Zr$_8$Ni$_{21}$ ($\sim$11\%) have been found at room temperature from PAC measurements. At 773 K, Zr$_9$Ni$_{11}$ partially decomposes to Zr$_7$Ni$_{10}$ and at 973 K, it is completely decomposed to ZrNi and Zr$_7$Ni$_{10}$. In Hf$_9$Ni$_{11}$, a predominant phase ($\sim$81\%) due to HfNi is found at room temperature while the phase Hf$_9$Ni$_{11}$ is produced as a minor phase ($\sim$19\%). No compositional phase change at higher temperature is found in Hf$_9$Ni$_{11}$. Phase components found from XRD and TEM/SAED measurements are similar to those observed from PAC measurements. Electric field gradients in Zr$_9$Ni$_{11}$ and Hf$_9$Ni$_{11}$ have been calculated by density functional theory (DFT) using all electron full potential (linearized) augmented plane wave plus local orbitals [FP-(L)APW+lo] method in order to assign the phase components., arXiv admin note: text overlap with arXiv:1703.10035

We study the properties of the single large adiabatic polaron in the substances composed of three parallel equally separated coplanar molecular chains. Particular attention has been devoted to the influence of the interchain coupling strength on polaron stability in order to elucidate the origin of the large polaron existence, which, contrary to the predictions of continuum adiabatic theories may persist in realistic conditions. Our results indicate the existence of the effectively two-dimensional stationary polarons with comparably large longitudinal radius while the transverse one ranges from zero, in the absence of interchain coupling, to approximately twice of the interchain separation when coupling strength tends towards the infinity. These two-dimensional polarons are both energetically and dynamically stable. This is quite the opposite to the expectations based on the traditional adiabatic large polaron theories which, in the case of short ranged electron phonon interaction, predict that the stable large polaron may exist only in 1D systems. Stability of these 2D polarons increases with the increase of the interchain coupling strength so that they may be comparably more stable than the pure 1D polarons. (C) 2015 Elsevier Ltd. All rights reserved.

In this paper we present the study of the transversal and longitudinal acceptance and the transmission efficiency in the injection, acceleration, and extraction systems in the separated sector cyclotron of the heavy ion research facility in Lanzhou, China. The study of cyclotron acceptance is done for 238U36+ with energy of 97 MeV/u and for 70Zn10+ with energy of 5.62 MeV/u under the theoretical isochronous and real magnetic field distribution. From the simulation results it can be seen that the transmission efficiency and the acceptances of separated sector cyclotron can be improved by redesign the curvature of MSI3 deflector or by introducing the magnet shim in MSI3 deflector region to change the distribution of the inner magnetic field. [Projekat Ministarstva nauke Republike Srbije, br. OI-171018]

In this paper the detailed structure of the transport beam line design is proposed, quadrupoles and deflectors specifications in order to transport the beam from the optic adaptation point in the SPIRAL2 production building up to the adaptation point in the DESIR hall. All optical elements, in beam line, are electrostatic and so, settings are independent of the ratio q/m of the particle. The calculations are done by COSY INFINITY computer code in first order of approximation and without fringe field effects. The beam emittances at the starting point (adaptation point in the SPIRAL2 production building) in horizontal and vertical planes are 80p mm mrad. The beam line is designed in such a way that the beam sizes, in both planes, at the end (adaptation point in the DESIR hall) are kept the same as they are at the starting point; the horizontal and vertical displacements from the optic axis at starting and ending points are the same, ±6 mm. In such case the efficiency of transport of the beam is high. [Projekat Ministarstva nauke Republike Srbije, br. OI-171018]

Time-differential perturbed angular correlation (TDPAC) measurements have been carried out in stoichiometric ZrNi$_3$ and HfNi$_3$ intermetallic compounds using $^{181}$Ta probe in the temperature range 77-1073 K considering the immense technological applications of Zr-Ni and Hf-Ni intermetallic compounds. In ZrNi$_3$, four components due to the production of Zr$_2$Ni$_7$, Zr$_8$Ni$_{21}$, Zr$_7$Ni$_{10}$ and ZrNi$_3$ have been found at room temperature. The HfNi$_3$ sample produces five electric quadrupole interaction frequencies at room temperature. The phase HfNi$_3$ is strongly produced in stoichiometric sample of HfNi$_3$ where two non-equivalent Hf sites are found to be present. Besides this phase, two other phases due to Hf$_2$Ni$_7$ and Hf$_8$Ni$_{21}$ have been found but, we do not observe any phase due to Hf$_7$Ni$_{10}$. X-ray diffraction, TEM/energy dispersive X-ray spectroscopy (EDX) and TEM-selected area electron diffraction (SAED) measurements were used to further characterize the investigated materials and it was found that these results agree with the TDPAC results. In order to confirm findings from TDPAC measurements, density functional theory (DFT) based calculations of electric field gradients (EFG) and asymmetry parameters at the sites of $^{181}$Ta probe nucleus were performed. Our calculated results are found to be in excellent agreement with the experimental results.

Substitutionally and interstitially Cu/Nco-doped anatase TiO2(101) surface is investigated by using density functional theory (DFT) calculations. The results suggest improved visible light photocatalytic activity over undoped anatase TiO2. Sizable lattice relaxation around the dopants is observed, followed by a formation of N-O bond. Depending on the local arrangement of atoms, localized states above the valence band maximum, deep into the band gap, and below the conduction band minimum are found. In addition, our calculation also predict band gap narrowing. The hybridization of the Cu 3d and N 2p states within the band gap and the other electronic and optical properties suggest a synergistic effect of the dopants in the enhancement of the visible light absorption on the (101) anatase surface. (C) 2017 Elsevier B.V. All rights reserved.

Magnetic ground states, local crystallographic environment of Fe, and hyperfine interaction parameters in tetragonal FeX (X = S, Se, Te) are investigated by means of density functional theory (DFT) calculations using augmented plane waves plus local orbitals (APW + lo) method. We use several different magnetic configurations to evaluate the magnetic and electronic properties of this system, as well as the hyperfine interaction parameters at Fe lattice site. The results obtained for the ground state collinear anti-ferromagnetic arrangement relatively well reproduce the quadrupole splitting and isomer shifts from the available Mossbauer measurements. The Baders atoms in molecule charge density analysis indicates bonding of closed-shell type and a sizable charge transfer from Fe to X. The system properties are sensitive to the structural optimization of the position of the chalcogen atom with respect to the iron plane. (C) 2017 Elsevier B.V. All rights reserved.

A high-resolution separator for the SPIRAL2/DESIR project at GANIL has been designed. The extracted isotopes from SPIRAL2 will be transported to and cooled in a RFQ cooler yielding beams with very low transverse emittance and energy spread. These beams will then be accelerated to 60 keV and sent to a high-resolution mass separator where a specific isotope will be selected. The good beam properties extracted from the RFQ cooler will allow one to obtain a mass resolution of c26000 with the high-resolution mass separator.

Short-lived exotic nuclei can be produced and separated with the high-energy nuclear beam facility called fragment separator at the Centre for Heavy Ion Research. These nuclides can be injected and stored in the storage ring called experimental storage ring. The lower lifetime limit of the presently existing methods for mass measurements on these nuclides at the experimental storage ring is about a few seconds. We have developed and investigated an isochronous operational mode of the future collector ring, that makes mass measurements feasible for nuclides with lifetimes down to a few microseconds. A mass resolving power of about 150 000 is expected.

Interactions induced in Al/Ti multilayers by implantation of Ar ions at room temperature were investgated. Initial structures consisted of (Al/Ti) x 5 multilayers deposited by d.c. ion sputtering on Si(1 0 0) wafers, to a total thickness of similar to 250 nm. They were irradiated with 200 keV Ar+ ions, to the fluences from 5 x 10(15) to 4 x 10(16) ions/cm(2). It was found that ion irradiation induced a progressed intermixing of the multilayer constituents and Al-Ti nanoalloying for the highest applied fluence. The resulting nanocrystalline structure had a graded composition with non-reacted or interdiffused Al and Ti, and gamma-AlTi and AlTi3 intermetallic phases. Most intense reactivity was observed around mid depth of the multilayers, where most energy was deposited by the impact ions. It is presumed that Al-Ti chemical reaction is triggered by thermal spikes and further enhanced by chemical driving forces. The applied processing can be interesting for fabrication of tightly bond multilayered structures with gradual changes of their composition and properties. (C) 2011 Elsevier B. V. All rights reserved.

This paper presents analysis of detector solenoid effects on primary disrupted beam in the ILC 14 mrad extraction line and their compensation. Particle tracking simulations are performed for evaluation of the extracted beam loss as well as of beam distribution and polarization at Compton interaction point (IP). The calculations are done both without and with compensation of the solenoid induced perturbations: the residual orbit, dispersion and focusing. The proposed correction system includes a detector integrated dipole field and a set of dipole and quadrupole correctors. This system effectively minimizes the growth of particle amplitudes induced by the solenoid; and therefore it keeps at minimum the corresponding growth of beam loss and helps to maintain the design beam properties at Compton IP for polarization measurement. The presented results are obtained for the baseline ILC energy of 500 GeV center-of-mass and three options of initial beam parameters. (C) 2009 Elsevier B.V. All rights reserved.

In this paper is studied the effects of the fringe field in the spiral inflector. (c) 2009 Elsevier B.V. All rights reserved.

The user friendly version of the ANAMARI code, originally developed for the separator settings determination and prediction of evaporation residue distribution at the focal plane for the Dubna gas-filled recoil separator, is used here to deduce the optimal design parameters for the super separator spectrometer (S-3), now in the phase of conceptual consideration. In particular, the ANAMARI code is used for the evaluation of the dependence of evaporation residue acceptance oil particle evaporation and multiple scattering effects in the target for the fusion reactions Ca-48 + Pb-206, Ca-48 + Os-192, Ca-48 + Cm-248, Ti-46 + Ni-58 and Cr-50 + Ni-58 which are taken as the samples of typical S-3 studies for: synthesis of super-heavy nuclei, the spectroscopy of very-heavy nuclei and super-heavy nuclei and the properties of double magic nuclei. (C) 2008 Elsevier B.V. All rights reserved. 15th International Conference on Electromagnetic Isotope Separators and Techniques Related to their Applications, Jun 24-29, 2007, Deauville, France

The stability and structure of titanium doped gold clusters (AunTi; n = 1-32) are studied by density functional theory calculations, as implemented in the first principles code SIESTA. The exchange and correlation effects were calculated within the generalized gradient approximation (GGA) parametrized by Perdew, Burke and Ernzerhof (PBE). We used norm conserving Troullier-Martins pseudopotentials for the 10-electron valence configuration of Ti and 11-electron valence configuration of Au. All calculations were spin-polarized. The global energy minimum geometries of the clusters were searched for by using the simulated annealing technique. The stability of the clusters is discussed on the basis of the binding energy per atom, second-order energy difference, vertical ionization potential, vertical electron affinities, HOMO-LUMO energy gap and vibrational frequencies. Based on the simultaneous criteria of high binding energy, high band gap, high vertical ionization potential, and low electron affinity, it is found that Au4Ti and Au14Ti clusters have a higher stability and are candidates for magic clusters, which confirms the already known results from previous works. The new result presented in this paper is that the Au20Ti and Au30Ti clusters have a higher stability too. In general, the clusters with even n are more stable than the clusters with odd n. Most of the clusters with even n are non-magnetic (total magnetic moment is zero). Our results also suggest that only the Au3Ti, Au7Ti and Au8Ti clusters have a planar structure. (C) 2016 Elsevier B.V. All rights reserved.

We consider the properties of the large acoustic polarons in a media composed of three parallel coupled identical macromolecular chains in an equilateral triangular arrangement. The existence of the truly three-dimensional large polarons has been demonstrated. Their appearance demands the complex interference of the effects of the reduced dimensionality, the nature and strength of the interchain coupling and particular geometrical arrangement of molecular chains. Different types of solutions were found and criteria for their existence were formulated in terms of the dimensionless interchain coupling parameter. (C) 2016 Elsevier Ltd. All rights reserved.

This paper deals with X-ray spectrum measurement as a method for the measurement of radio frequent cavity voltage and the theory of X-ray spectrum calculation. Experimental results at 72 MHz for three different values of the radio frequent power of ACCEL K250 super conducting cyclotron are being presented.

The influence of the iron shield of the solenoid on spin tracking is studied in this paper. In the case of the 200 MeV proton, the study has been numerically done in the ZGOUBI code. The distribution of the magnetic field was done by POISSON. We have come to the conclusion that the influence of the solenoid?s shielding on spin tracking is the same at its entrance and exit and that is directly proportional to the intensity of the magnetic induction B on the axis of the solenoid. We have also determined that the influence of the solenoid?s shielding is much stronger on transversal components of the spin than on its longitudinal component. The differences between components of the spin for the shielded and not-shielded solenoid diminish with the in crease in the distance from the solenoid.

At Kernfysisch Versneller Institute, optical properties of injection transport beam were studied. Measurements of beam size and emittance determined by "varying quadrupole method" are compared with calculations including fringe fields up to the third order with the COSYINFINITY code. Calculations and measurements qualitatively match; the calculations reflect the observed large beam losses. On the basis of the calculations new settings have been determined, resulting in a significant increase of the transmission. To achieve full transmission a complete redesign of the beam line is needed, in particular of the bending magnets.

First principles calculations were performed in the framework of the density functional theory (DFF) using the Full Potential-Linear Augment Plane Wave method (FP-LAPW) within the generalized gradient approximation (GGA) to predict the structural, electronic, elastic and thermal properties of NiTi2 intermetallic compound. By using the Wien2k all-electron code, calculations of the ground state and electronic properties such as lattice constants, bulk modulus, presure derivative of bulk modulus, total energies and density of states were also included. The elastic constants and mechanical properties such as Poissons ratio, Youngs modulus and shear modulus are estimated from the calculated elastic constants of the single crystal. Through the quasi-harmonic Debye model, the preasure and temperature dependences of the linear expansion coefficient, bulk modulus and heat capacity have been investigated. Finally, the Debye temperature has been estimated from the average sound velocity according to the predicted polycrystal bulk properties and from the single crystal elastic constants. (C) 2015 Elsevier Ltd. All rights reserved.

This paper describes the design of the central region for h=2 and 3 modes of acceleration in the Warsaw K-160 cyclotron. The central region is unique and compatible with the two above-mentioned harmonic modes of operation. Only one spiral type inflector will be used. The electric field distribution in the inflector and in the four acceleration gaps has been numerically calculated from an electric potential map produced by the program RELAX3D. The geometry of the central region has been tested with the computations of orbits carried out by means of the computer code CYCLONE. The optical properties of the spiral inflector and the central region were studied by using the programs CASINO and CYCLONE, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.

This paper compares some optical properties of different spiral inflectors using the program CASINO. The electric field distribution in the inflectors has been numerically calculated from an electric potential map produced by the program RELAX3D. The magnetic field is assumed to be constant. We have also made an effort to minimize the inflector fringe field using the RELAX3D program. (C) 1999 Elsevier Science B.V. All rights reserved.

In this paper is represented the results of beam profile measurements of He-3(+) beam delivered from ECR ion source at KVI. The beam emittance is estimated by varying quadrupole method. The estimated values for the beam emittance at the different profile grid locations along the transport beam line shows that beam emittance in the both, horizontal and vertical planes is not conserved. That means there is a strong-coupling effect and/or the beam is losing through the transport line. (c) 2005 Published by Elsevier B.V. 8th International Computational Accelerator Physics Conference, Jun 29-Jul 02, 2004, St Petersburg State Univ, St Petersburg, Russia

The effects of Ar ion irradiation on interfacial reactions induced in Ni/Ti multilayers were investigated. Structures consisting of 10 alternate Ni (similar to 26 nm) and Ti (similar to 20 nm) layers of a total thickness similar to 230 nm were deposited by ion sputtering on Si (1 0 0) wafers. Argon irradiations were done at 180 keV, to the doses of 1-6 x 10(16) ions/cm(2), the samples being held at room temperature. The projected implanted ion range is 86 +/- 36 nm, maximum energy loss is closer to the surface, and maximum displacements per atom (dpa) from 47 to 284 for Ni and 26 to 156 for Ti. Characterizations of samples were performed by transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS). It is shown that ion irradiation induced a progressed intermixing in the mostly affected zone already for the lowest dose, the thickness of the mix increasing linearly with the irradiation dose. The mixed phase is fully amorphous, starting with a higher concentration of Ni (which is the diffusing species) from the initial stages, and saturating at Ni: Ti similar to 66:34. A thick amorphous layer (similar to 127 nm) formed towards the surface region of the structure for the irradiation dose of 4 x 10(16) ions/cm(2) remains stable with increasing the dose to 6 x 10(16) ions/cm(2), which introduces up to 6-7 at.% of Ar within the mix. The results are discussed in light of the existing models. They can be interesting for introducing a selective and controlled solid-state reaction and towards further studies of ion irradiation stability of amorphous Ni-Ti phase. (C) 2013 Elsevier B.V. All rights reserved.

Properties of the large acoustic polarons in discrete molecular chains have been investigated within the adiabatic approximation. It turns out that practically all the polaron features are determined by the single parameter-coupling constant which represents the ratio between the small polaron binding energy and the electron bandwidth. Three different types of stationary solutions were found corresponding to weak, intermediate, and strong coupling limits, respectively. In the weak coupling regime, that is, for the values of coupling constant exceeding the limit of the applicability of continuum approximation but lower than the critical one ( $g_C$), we observe symmetric bond-centered solution corresponding to the polaron positioned in the middle between the adjacent lattice sites. When coupling constant overgrows, this critical value transition toward the site-centered state occurs. It takes place continuously through the intermediate asymmetric state whose position gradually approaches lattice site as coupling constant increases. One of the main consequences of the lattice discreteness is the emergence of the periodic potential, Peierls-Nabarro potential relief, through which polarons have to pass to transfer along the chain. The conditions for the polaron propagation are formulated in terms of the threshold velocity. (c) 2012 Wiley Periodicals, Inc.

A challenge for nuclear physics is to measure masses of exotic nuclei up to the limits of nuclear existence which are characterized by low production cross sections and short half-lives. The large acceptance Collector Ring (CR) at FAIR tuned in the isochronous ion-optical mode offers unique possibilities for measuring short-lived and very exotic nuclides. However, in a ring designed for maximal acceptance, many factors limit the resolution. One point is a limit in time resolution inversely proportional to the transverse emittance. But most of the time aberrations can be corrected and others become small for large number of turns. We show the relations of the time correction to the corresponding transverse focusing and that the main correction for large emittance corresponds directly to the chromaticity correction for transverse focusing of the beam. With the help of Monte-Carlo simulations for the full acceptance we demonstrate how to correct the revolution times so that in principle resolutions of dm/m=1E-6 can be achieved. In these calculations the influence of magnet inhomogeneities and extended fringe fields are considered and a calibration scheme also for ions with different mass-to-charge ratio is presented., 6 figures, recised version May 2013

We study the influence of temperature on large polarons in DNA molecules. Employing the mean field approximation we derive the slight generalization of the SSH Hamiltonian with temperature dependent parameters. It was found that the degree of the modification of system parameters is very weak at physiologically relevant temperature which indicates that the free acoustic polarons as charge carriers may be responsible for DNA conductivity. 1st Euro Mediterranean Meeting on Functionalized Materials (EMM-FM), Sep 06-10, 2011, Sousse, Tunisia

The ILC baseline extraction line is designed for 14 mrad horizontal crossing angle between e{sup +} and e{sup -} colliding beams at Interaction Point (IP). The extraction optics in the Interaction Region (IR) includes a detector integrated dipole field (anti-DID) to reduce orbit perturbation caused by the detector solenoid and minimize detector background. This paper presents a study of random field and alignment errors in the extraction magnets, compensation of the induced orbit perturbation, and effects of errors on extraction beam power loss. The results are obtained for the baseline ILC energy of 500 GeV center-of-mass and three options of beam parameters.

Expressions which can be used to calculate the focusing coefficients applicable to the interior regions (no fringe fields) of magnetic helical hexapole lenses of infinite length have been derived through second-order. It is shown that the helical hexapole has better focusing properties than the non-helical case. Expressions for the aberration coefficients are derived and, for appropriate value of the twisted angle, the helical hexapole reduces aberrations compared to the non-helical case. The numerical examples of a magnetic helical hexapoles in the case of a 25 MeV proton and 250 GeV electron beams are performed. (c) 2007 Elsevier B.V. All rights reserved.

This paper presents analytical and numerical solutions of space-charge effects in the beam in the twisted quadrupole. It considers the effects of space-charge forces on an elliptical beam with a uniform particle distribution. Effects of the space charge on the transfer matrix of the twisted quadrupole are examined and the transfer matrix is explicitly derived. The numerical solution of the beam line segment consisting of two drift lengths separated by a twisted quadrupole (electrostatic) in the case of 10eV and 25keV proton beam is performed, taking into account the effects of the fringe fields. (c) 2005 Elsevier B.V. All rights reserved.

The origin of the low transmission through the low energy beam line between the electron cyclotron resonance source and the AGOR cyclotron has been investigated. Measurements of beam size and emittance, determined with the "varying quadrupole method," are compared with calculations including fringe fields up to third order with the code COSY INFINITY. Calculations and measurements qualitatively agree; the calculations exhibit the large beam losses observed. On the basis of the calculations new settings have been determined, resulting in a significant increase of the transmission. To achieve full transmission a complete redesign of the beam line, in particular of the bending magnets, is needed. (C) 2005 American Institute of Physics.

This paper describes the design of the central region in the Gustaf Werner cyclotron for h = 1, 2 and 3 modes of acceleration. The electric field distribution in the inflector and in the four acceleration gaps has been numerically calculated from an electric potential map produced by the program RELAX3D. The geometry of the central region has been tested with the computations of orbits carried out by means of the computer code CYCLONE. The optical properties of the spiral inflector and the central region were studied by using the programs CASINO and CYCLONE, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.

In this paper we present the theory of the horizontal motion ions through the acceleration gap in the case of a static magnetic field and time-varying electric field. It also describes the motion of the center of the ion trajectory through the acceleration gap and also during the acceleration process. The result also describes analytically the angle through which the ion passed (so called flying angle) between two acceleration gaps. That angle can be measured from the center of the ion trajectory or from the center of the cyclotron. The analysis shows that the flying angle of the ions measured in these two reference systems is not same. Namely, the flying angle of the ion measured from the center of its trajectory is bigger than in the case when the flying angle is measured from the center of the cyclotron. It shows that difference between flying angle in these two reference systems becomes less and less during acceleration process. (C) 2002 Elsevier Science B.V. All rights reserved.

This paper presents the analytical and numerical theory of the paraxial ion trajectory through the spiral inflector. Analytical expressions for the equations which describe the paraxial ion trajectory are derived. The analytical derivations of the electric field expansion around the central ion trajectory has also been studied. (C) 2000 Elsevier Science B.V. All rights reserved.

This paper presents the analytical and numerical theory of the space charge effects in the beam in the spiral inflector. It considers a simplified model of a straight cylindrical beam by using a uniform particle distribution. Numerical results represented in this payer are obtained by using a modified version of the program CASINO. (C) 2000 Elsevier Science B.V. All rights reserved.

This paper presents the analytical and numerical theory of the central ion trajectory through the spiral inflector. Analytical expressions for the equations which describe the central ion trajectory are derived. (C) 2000 Elsevier Science B.V. All rights reserved.

This paper describes the modification design of the central region for h = 2 mode of acceleration in the RIKEN AVF cyclotron. we made a small modification to the electrode shape in the central region for optimization of the beam transmission. The central region is equipped with an axial injection system. The spiral type inflector is used for axial injection. The electric field distribution in the inflector and in four acceleration gaps has been numerically calculated from an electric potential map produced by the program RELAX3D. The magnetic field is measured. The geometry of the central reg ion has been tested with the computations of orbits carried out by means of the computer code CYCLONE. The optical properties of the spiral inflector and the central region are studied by using the program CASINO and CYCLONE, respectively. We have also made an effort to minimize the inflector fringe field effects using the RELAX3D program. (C) 1999 Elsevier Science B.V. All rights reserved.

This paper describes the redesign of the low-energy beam line at KVI. Redesigned and properties of the optical elements of the transport beam line is done by using the code COSY INFINITY in the third-order of approximation. The effects of fringe fields of the optical elements are also taken into account in the third order of accuracy. Examples of beam transport calculations and emittance measurements are shown in the case of He-3(+). The beam emittance is estimated by varying quadrupole method. By using COSY code it is concluded that the settings of some optical elements in the present design of the beam line should changed to increase the beam transmission. In this way the beam transmission is increased 2-3 times. To achieve higher beam transmission the redesign of the beam line is necessary. (c) 2005 Published by Elsevier B.V. 8th International Computational Accelerator Physics Conference, Jun 29-Jul 02, 2004, St Petersburg State Univ, St Petersburg, Russia

This paper describes the design of the central region for h = 1, h = 2 and h = 4 modes of acceleration in the VINCY cyclotron. The result which is worth reported in that the central region is unique and compatible with the three above mentioned harmonic modes of operation. Only one spiral type inflector will be used. The central region is designed to operate with two external ion sources: (a) an ECR ion source with the maximum extraction voltage of 25 kV for heavy ions, and (b) a multicusp ion source with the maximum extraction voltage of 30 kV for H− and D− ions. Heavy ions will be accelerated by the second and fourth harmonics, D− ions by the second harmonic and H− ions by the first harmonic of the RF field. The central region is equipped with an axial injection system. The electric field distribution in the inflector and in the four acceleration gaps has been numerically calculated from an electric potential map produced by the program RELAX3D. The geometry of the central region has been tested with the computations of orbits carried out by means of the computer code CYCLONE. The optical properties of the spiral inflector and the central region were studied by using the programs CASINO and CYCLONE respectively. We have also made an effort to minimize the inflector fringe field using the RELAX3D program.

In Refs. [1–4] the theory of ion trajectory through a spiral inflector was studied in a very detailed way, but some mathematical details as to how the differential equation of ion motion can be solved are still missing. In Ref. [5] these mathematical details are presented, but the careful reader will notice a mathematical inconsistency which can be the source of the wrong conclusion that an analytical solution of the central ion trajectory through the spiral inflector is not unique. As the author of Ref. [5] I feel a need and responsibility to eliminate that mathematical inconsistency. In Ref. [5] the differential equation of the projection of the ion trajectory into the x–y plane, Eq. (25), is not solved correctly from the mathematical point of view, but its parametric solutions (Eqs. (36a) and (36b)) are correct. We will try to solve again Eq. (25), but now in a consistent way from the mathematical point of view. We will use the same symbols as Ref. [5] with the same meanings. 2. Correct solution of the differential equation