bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation with solar cycle of the diurnal variation of cosmic rays underground
Authors: Regener Victor H. , Swinson Derek B.
Published: April 2011

The cosmic-ray diurnal variation has been observed with scintillator telescopes at a depth of 40 m.w.e. at Chacaltaya, Bolivia, since the last solar maximum, and at the same depth near Albuquerque, New Mexico, since the last solar minimum. During the solar maximum from 1958 to 1960 the amplitude of the diurnal variation was 0.3% for the Chacaltaya telescopes, but at solar minimum early in 1965 it was as low as 0.05%. Since that time, the amplitude has been steadily increasing, and it is now between 0.1% and 0.2% at both the Bolivia and the New Mexico stations.The telescopes measure the cosmic-ray flux from the north, south, east, and west directions, as well as from the vertical; and the various observed times of the diurnal maximum for these directions confirm the extraterrestrial nature of the anisotropy. The maximum occurs at approximately 15 h local solar time in the vertical telescopes. A study of the asymptotic directions of these telescopes for differing primary energies, and of the behavior of the phases of the diurnal variation at the two stations, gives indications of the energies of the primary particles responsible for the diurnal variation. The results are compared with the models of Axford and of Ahluwalia and Dessler.
East/west directional measurements of the cosmic-ray solar daily variation at an equatorial station
Authors: Hashim A. , Thambyahpillai T. , Thomson D. M. , Mathews T.
Published: April 2011

Two large scintillator telescopes of cubical geometry, tilted at an angle of 45° to the vertical, were set up pointing in the east and west directions at the equatorial station Makerere. Data from these telescopes are available from July 1964 onwards. During the initial year of observation the solar diurnal variation in both telescopes, after pressure correction, had an amplitude of about 0.2%, but the absence of any appreciable phase difference between the east and west directions suggests that in the intermediate range of rigidities (say 50–150 GV) there was no appreciable primary anisotropy during the last solar minimum. This conclusion is in agreement with that drawn from similar measurements made at Chacaltaya. The large amplitude of the Makerere diurnal variation, however, suggests that there is a substantial "local" source of the diurnal variation which is significantly different from that observed at Chacaltaya. The possible origin of this "local" source is briefly discussed.
Diurnal cosmic-ray variation with the inclusion of the geometrical effects and the asymptotic cones of approach
Authors: Dorman L. I. , Fischer S.
Published: April 2011

Employing the data from cosmic-ray neutron monitors at high latitude, the spatial distribution of the axis of the diurnal anisotropy is determined. The effects of the earth's revolution around the sun on the diurnal intensity variation is investigated. A new method for further investigation of the spatial distribution of the anisotropy and for the determination of its spectra in various directions has been proposed.
The daily-variation second harmonic and a cosmic-ray intensity gradient perpendicular to the ecliptic
Authors: Lietti B. , Quenby J. J.
Published: April 2011

Since the spiral interplanetary magnetic field is expected to be much less tightly wound at high solar latitudes, galactic particles arriving along the sun's polar field lines may suffer much less modulation than those arriving in the ecliptic plane. Hence a rising cosmic-ray density gradient is expected away from the ecliptic which will give rise to a second harmonic in the cosmic-ray daily variation with maxima at right angles to the spiral field direction. Two extreme models for the gradient are considered: one for predominantly particle diffusion along the field lines and the other when the diffusion is all perpendicular to the lines. Both models give a first positive power of rigidity dependence to the second harmonic in the 1 to 15 GV range with a double amplitude of about 0.05% at 10 GV. This is in rough accord with experimental results, which also can be shown to favor the parallel diffusion model at higher rigidities.
Cosmic-ray observations in 1964–65 with Mariner IV
Authors: Krimigis S. M.
Published: April 2011

The University of Iowa equipment on Mariner IV, which was launched towards Mars on 28 November 1964, consists in part of two thin-window G-M tubes sensitive to electrons of [Formula: see text] (detector B) and [Formula: see text] (detector A), and a shielded G-M tube (detector C) sensitive to electrons of Ee > 150 keV and having a threshold of ~55 MeV for omnidirectional protons. Observations over the period 28 November 1964 to 30 September 1965 have shown the following: (a) Electrons in the energy range [Formula: see text] were present in the interplanetary medium prior to day 12, 1965 with intensities of ~0.5 (cm2 s sr)−1. (b) The interplanetary cosmic-ray gradient for protons of [Formula: see text] was less than 3% per AU and the data are consistent with zero gradient. (c) There are large changes in the intensities of protons of [Formula: see text], but the direction and magnitude of the gradient for such protons were uncertain during solar minimum. The implications of these results are discussed.
Cosmic-ray fast-neutron flux measurements in the atmosphere at various latitudes
Authors: Korff S. A. , Mendell R. B. , Merker M. , Sandie W.
Published: April 2011

We have extended in time our series of balloon flights, made at several latitudes between Hyderabad, India, and Ft. Churchill, Manitoba, to altitudes close to the top of the atmosphere. In these flights the neutrons generated by the cosmic radiation in the energy interval between 1 and 10 MeV are measured. The first set of measurements was made during the period of the minimum of solar activity, and the more recent flights carry the work into the start of the next solar cycle. A decrease in intensity at high elevations with the onset of the present solar cycle has been noted. Further data were also obtained on an airplane flight around the world over both poles, thus covering the full range of latitudes at two opposite longitudes. The relationship between the observed neutron spectrum and that derived by the use of a neutron transport code will be discussed. We shall also discuss other factors emerging from this analysis, including the numbers for radiocarbon production and the leakage flux.
Complete sets of observables
Authors: Prugovečki Eduard
Published: April 2011

The concept of a complete set of observables is formulated in the Hilbert space formalism in a manner which agrees with Dirac's original intuitive formulation. Theorems are derived which relate the completeness of a commuting set of observables to the existence of a cyclic vector. It is shown that any operator which commutes with a complete set of observables is a function of those observables.
Effective neutron capture cross section and half-life of 155Eu
Authors: Mowatt R. S.
Published: April 2011

The half-life of 155Eu has been measured to be 4.65 ± 0.20 years and the absorption cross section has been found to be 4040 ± 125 b by a depletion method using a Ge(Li) detector. The sample of 155Eu was irradiated in the NRU pneumatic carrier where the flux has a small epithermal component. These values are very different from values of [Formula: see text] years and σ ~ 13 000 b reported previously.
The Spectrum of AsF in the Near Vacuum Ultraviolet and Near Infrared Regions
Authors: Liu D. S. , Jones W. E.
Published: April 2011

Three singlet–triplet transitions, b1Σ+−X3Σ−, c1Π–X3Σ−, and d1Π–X3Σ−, and two 3Π–X3Σ− transitions attributed to the molecule AsF, have been found in the regions 1900–2300 Å and 7000–7400 Å. The vibrational analysis for the observed systems and the rotational analysis of the singlet–triplet transitions are complete. The analysis shows that the ground state X3Σ− belongs to Hund's case c with a spin coupling constant λ of about 70 cm−1. The analysis of the observed transitions and a discussion of the relative position and molecular configurations of the observed states are presented.
Delayed Coincidence Measurement of the Picoseconds Lifetime of the 9.699 MeV (5−) Level of 28Si
Authors: Barton R. D. , Wadden J. S. , Carter A. L. , Pai H. L.
Published: April 2011

A description of a measurement of the lifetime of the 9.699 MeV (5−) level of 28Si by our improved self-comparison delayed coincidence method is given. We obtain (8 ± 4) ps. This is consistent with our Doppler shift attenuation method measurement which gives (3.3 ± 0.8) ps, where the quoted error contains no allowance for uncertainties in F(τ). This consistency gives support to the extension of our delayed coincidence measurements into the picoseconds range.
Electromagnetic Waves on a Conducting Infinite Cylinder in a Magnetoionic Medium
Authors: Einarsson Olov
Published: April 2011

A characteristic equation is investigated which is related to a perfectly conducting infinite circular cylinder immersed in a homogeneous magnetoionic medium with the magnetic field parallel to the cylinder axis. It is found that in most cases one root of the characteristic equation contributes to the current on the cylinder surface when the contour of integration for the Fourier transform representation of the current is deformed into the path of steepest descent. Zeroth-order expressions for the admittance of a thin infinite antenna are given and compared to existing results based on numerical integration of the Fourier integral.
Photoneutron Disintegration of 40Ar
Authors: Jury J. W. , Lodge J. I. , Lokan K. H. , Sherman N. K. , Gellie R. W.
Published: April 2011

Photoneutron energy spectra from 40Ar have been measured at bremsstrahlung end-point energies from 13 to 23 MeV in 1 MeV steps. The differential cross section at 90° for the reaction 40Ar(γ, n0)39Ar revealed some 26 previously unreported excited states of 40Ar in the region below 13 MeV. The envelope of these states suggests a single particle resonance involving the valence 1f7/2 neutrons. The measured total neutron cross section exhibits a marked change from this single particle behavior at about 14 MeV where collective effects begin to dominate and neutrons are emitted to highly excited states of 39Ar.
A comparison of sectioning methods used to measure concentration profiles in anodic oxides
Authors: Pringle J. P. S.
Published: April 2011

Sectioning procedures for anodic tantalum, tungsten, and aluminum oxides can be combined with a least squares fit analysis, and used to measure range profiles for implanted radioactive species. Results obtained with the three oxides are compared, and the measurements in anodic tantalum oxide shown to be most accurate. Range profiles for the same species implanted at the same energy into both anodic tantalum and tungsten oxides were found to be the same within experimental error, as expected from their amorphous nature and similar mix of very light and very heavy atoms. Results obtained with these procedures were used as tests for sectioning methods based on mechanical polishing and sputtering; these proved less accurate, and were unable to identify the form of the concentration profile. They could, however, be used to measure mean depths, and would provide an approximate measure for the standard deviation.
A theory of gravity
Authors: Rastall Peter
Published: April 2011

It is known that a slight generalization of the Newtonian theory of gravity is compatible with all present-day observations. This 'super-Newtonian' theory is not a complete theory of gravity, since it applies only to static or quasistatic gravitational fields. We develop here a simple, complete theory of gravity that contains the super-Newtonian theory as a special case. The gravitational field is described in terms of two real functions, and the field equations are derived from a variational principle. The homogeneous cosmological solutions of the field equations all correspond to open universes. The gravitational 'constant' decreases with time in the version of the theory that is compatible with Dicke's measurement of the solar oblateness, but not in the version compatible with an almost spherical Sun. The gravitational field of a slowly rotating body is not of the Lense-Thirring form.
Resonance neutron capture in silicon
Authors: Thomson V. J. , Prestwich W. V. , Kennett T. J.
Published: April 2011

Measurement of gamma rays following neutron capture has revealed resonances at 29, 67, 85, and 173 keV for the 28Si(n,γ)29Si reaction, and 16 and 35 keV for the 29Si(n,γ)30Si reaction. The characteristics of the resonance decay properties are discussed. Both the 67 and 85 keV resonances appear to result from p wave capture.
Transport properties of tungsten-doped VO2
Authors: Reyes J. M. , Sayer M. , Chen R.
Published: April 2011

Measurements of DC and AC conductivity and thermopower show that VO2: W can be treated as a conventional n-type extrinsic semiconductor with a donor level 0.06–0.08 eV below the conduction band. For samples with an impurity content from 0.67 → 1.70 at.% W, an effective mass ratio m*/m of 65 ± 10 and a compensation ratio of 0.7 ± 0.1 are deduced from conventional semiconductor theory assuming donor exhaustion just below the metal semiconductor transition.
A bibliography on collision-induced absorption
Authors: Rich Nathan H. , McKellar A. R. W.
Published: April 2011

A bibliography has been compiled which provides a comprehensive list of about 500 references to collision-induced absorption spectra in gases and liquids and some closely related areas. The compilation, which includes a topical index and cross-references to the names of all authors, is available from the Depository of Unpublished Data of the National Research Council of Canada.
Sensitized fluorescence in zinc, induced in collisions with excited Hg atoms
Authors: Czajkowski M. , Krause L.
Published: April 2011

The transfer of excitation energy, induced in inelastic collisions between excited Hg atoms and ground state Zn atoms, was studied using methods of sensitized fluorescence. Hg atoms in a low density Hg–Zn mixture were excited with Hg 2537 Å resonance radiation to the 63P1 state, and interacted with the Zn atoms which became collisionally excited to the 43P1 state and then decayed emitting sensitized fluorescence. Measurements of relative intensities of Hg 2537 Å resonance fluorescence and Zn 3076 Å sensitized fluorescence yielded the cross section of 5.9 × 10−2 Å2 for Hg(63P1) → Zn(43P1) excitation transfer. The addition of small quantities of N2 to the Hg–Zn vapor mixture enhanced the efficiency of the transfer. The cross section for quenching of the Zn 43P1 state by collisions with N2 was found to be 0.19 Å2.
Oscillator strengths for the 2P–2D transitions of the Al I sequence
Authors: Fischer Charlotte Froese
Published: April 2011

Theoretical first-order f values are reported for the 2P–2D transitions in the Al I sequence. Though length and velocity forms are in fair agreement for the whole sequence, a considerable discrepancy still exists between these theoretical results and those deduced from beam foil spectroscopy.
Dielectric relaxation of some aliphatic ketones in dilute solutions
Authors: Madan M. P.
Published: April 2011

The dielectric relaxation behavior of 2-butanone, 2-pentanone, 2-heptanone, and 3-nonanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride has been studied in the microwave region at a number of temperatures. The relaxation data have been used to estimate the free energy, enthalpy, and entropy of activation for the relaxation mechanism. The values of the relaxation time for those solutions for which there are available known data agree well with other determinations. The results have been discussed in terms of dipole reorientation by intramolecular and overall molecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.
Analyse expérimentale et théorique d'un laser CO2 TEA avec résonateurs instables
Authors: Lavigne P. , Lachambre J.-L. , Gilbert J. , Otis G.
Published: April 2011

This paper reports on an extensive parametric investigation of a TEA CO2 laser operated in an unstable confocal resonator. The coupling mirror diameter and the cavity magnification, M, which give the better use of the laser medium for different applications, are experimentally determined. These results are compared to the diffractional and geometrical theories of unstable resonators. It is found that, in our experimental conditions, the energy density in the focal plane of a lens depends only weakly on the value of M while the cavities having a magnification smaller than 2 are the most efficient in extracting the energy out of the lasing medium.
The oval of auroral hydrogen emissions
Authors: Montbriand L. E.
Published: April 2011

Diurnal curves of the average location of the equatorial edge of the auroral hydrogen oval (AHO) are presented for various levels of magnetic activity. Under absolutely quiet conditions this boundary is symmetrical about 23:15 corrected geomagnetic time (CGT), at which time it lies near 69.5° CG latitude. With increasing magnetic activity, it shifts equatorward and for Kp = 4 and 5 reaches 63° and exhibits a certain degree of asymmetry with its most equatorward position occurring at about 21:00 CGT. Isolated patches or luminous regions of hydrogenous aurora occasionally occur equatorward of the instantaneous equatorial boundary of the AHO, in a time interval extending from before 15:45 CGT (sunset) up to 00:30. Their occurrence has suggested that the polar pattern of auroral hydrogen emissions is composed of a permanent region which is commonly referred to as the AHO, and a temporary region, equatorward of it in the evening and afternoon where there occasionally can occur these patches of hydrogenous aurora.
Transmission d'images par modulation du spectre
Authors: Cielo P. , Delisle C.
Published: April 2011

In this paper, we describe an all-optical method of transmission of the information contained in a photographic transparency. The basic principle consists of modulating, by a one-dimensional transparency, the spectral density of a wide-band collimated light beam, which can be transmitted over several kilometres. The image of the photographic transparency is obtained by simply displaying the optical spectrum of the received light beam. As all resolvable details of the one-dimensional image are transmitted in parallel, this method makes it possible to reach a high information rate. We also show experimentally how a two-dimensional image can be reconstructed. The theoretical and practical limits to the transmission capacity of the system are analysed, and an information rate of 20 Mbits/s appears readily obtainable. The performance of this method compares advantageously with that of two other methods of wide-band light–wave communication (Delisle et Cielo; Froehly, Lacourt et Vienot). We also describe an experimental technique for correcting the problems arising from the wavelength-dependent absorption of the propagation material and the chromatic selectivity of the photographic emulsion. Finally, we emphasize the potential applications of this method in the area of computer to computer communication.
A comparison of the fixed-JT averaging and projected Hartree–Fock methods for nuclear structure studies
Authors: Ng W. Y. , Wong S. S. M.
Published: April 2011

Energy levels in the sd-shell are calculated for several different interactions to establish the usefulness of the fixed-JT averaging method (FJT) in the low-lying region by comparison with the results of the projected Hartree–Fock (PHF) method. It is found that, while the FJT errors are the largest near to the ground state, their absolute magnitudes are comparable to those of PHF.
Precise atomic mass differences for wide doublets as determined with the Manitoba II mass spectrometer
Authors: Southon F. C. G. , Meredith J. O. , Barber R. C. , Duckworth H. E.
Published: April 2011

In work reported previously, the 1 m radius, second-order, double-focusing mass spectrometer at the University of Manitoba ('Manitoba II') has been used to determine the spacing, ΔM, of relatively narrow mass spectral doublets (1/115 000 < ΔM/M < 1/17 000). In this work, involving relatively much wider doublets, we describe a systematic correction which must be applied to such determinations. We also report new values for the 37Cl – 35Cl mass difference and for two rare earth doublets which check the reliability of a large body of previous data.
Transport properties and the structure of vanadium phosphate glasses
Authors: Jordan B. D. , Calvo C.
Published: April 2011

The adiabatic hopping model for the electrical conductivity of the vanadium phosphate glasses, V1+xP1−xO5−c/2, is examined in terms of their structures as derived from recent X-ray studies. These indicate that the relevant concentration variable for rationalizing the Seebeck coefficient data is c, the fraction of non-tetrahedral vanadium ion sites which are polarons. The polarons interlayer coordination number is 3. The average hopping distance varies by only 5% for 0 ≤ x ≤ 1. The experimental conductivities compared with[Formula: see text]suggest that n is near 3 and that the jump frequency v0 varies by nearly a factor of 3 over the composition range.
Composantes cubiques normales des tenseurs spheriques
Authors: Champion J. P. , Pierre G. , Michelot F. , Moret-Bailly J.
Published: April 2011

The entire matrix which connects 'standard' to 'cubic normal' components of spherical tensors is defined. Numerical values of the matrix elements are given up to J = 15. The results may be used for proper or improper groups (SO(3), O(3) – O, Td, Oh) useful in atomic and molecular physics.
Decay of pair correlation functions
Authors: Tago Yoshio , Smith William R.
Published: April 2011

The decay equation, which determines the correlation length and the period of the pair correlation function of a fluid at large distances, is discussed using the Ornstein–Zernike equation when the direct correlation function vanishes rapidly at large distances. The decay equation is solved numerically using the exact hard sphere and sticky hard sphere fluid results from the Percus–Yevick approximation. In the case of the hard sphere fluid, oscillatory decay is always obtained. For the sticky hard sphere fluid, we obtain a locus both in the pressure–temperature plane and the density–temperature plane such that the decay is monotonic inside and oscillatory outside the locus.
Ferromagnetic antiresonance transmission through Supermalloy at 24 GHz
Authors: Cochran J. F. , Heinrich B. , Dewar G.
Published: April 2011

The magnetic field dependence of the transmission of 24 GHz radiation through ferromagnetic plates of Supermalloy approximately 10−2 cm thick has been investigated. The results have been interpreted using a theory which combines Maxwell's equations and the equation of motion for the magnetization, and which includes the possibility of the external magnetic field lying at any angle with respect to the specimen normal. The results of the measurements on four discs of Supermalloy at 1 °C were very consistent and resulted in the average values g = 2.106 ± 0.001, 4π7Ms = 7.531 ± 0.01 kOe, and a damping parameter, λ = (0.94 ± 0.05) × 108 s−1. Although transmission studies made on specimens thick compared to the skin depth are very useful for obtaining the magnetic damping parameter and magnetostatic parameters, the article also discusses the possibility of using transmission experiments on thinner specimens to study exchange and surface pinning of the magnetization.
Polarization in deuteron stripping on 12C at low energy
Authors: Sieminski Marek , Sosnowski Marek , Zupranski Pawel
Published: April 2011

Proton polarization in 12C(d,p0)13C reaction for deuteron energy from 2.34 to 2.74 MeV was measured and compared with earlier data at 3.18 MeV. Distorted Wave Born Approximation (DWBA) calculations show that a reasonable description of the cross-section and polarization data can be obtained for both 12C(d,p0)13C and 12C(d,n0)13N reactions if the depth of the deuteron spin–orbit potential is low. Significant stripping contribution is inferred even at resonance energies.
Vibrational analysis of the A2Π–X2Σ and B2Σ–X2Σ transitions of YS and rotational analysis of the B–X (0,0) band
Authors: Stringat R. , Fenot B. , Féménias J-L.
Published: April 2011

Transitions A2Π–X2Σ and B2Σ–X2Σ of YS have been studied in the spectral range between 6360 and ~ 8500 Å. Numerous perturbations are observed in the vibrational structure. Constants for states X(ωe = 492.7 cm−1, ωexe ~ 1.2 cm−1) and B(ωe = 449.7 cm−1, ωexe ~ 1.4 cm−1) were calculated from the heads. In the case of state A, it was shown only that [Formula: see text] and [Formula: see text].The analysis of the (0,0) band of the B–X system provided the following constants: X state: B″ = 0.13877 cm−1, D″ = 3.7 × 10−8 cm−1 state: B′ = 0.1330 cm−1, γ′0 = −0.154 cm−1, γ′N = 6.2 × 10−6 cm−1.
The weak neutral current: search for a 0− isomer in 42Sc and 46V
Authors: Jackson K. P. , Azuma R. E. , Berka I. , Faestermann T. , Geiger J. S. , Hardy J. C. , Schmeing H.
Published: April 2011

Isgur has shown that some properties of the weak neutral current can be studied by investigating a nuclear Jπ = 0− ↔ 0+ transition. We have used the (p,n) reaction on targets of 42Ca and 46Ti to populate states in the self-conjugate nuclei 42Sc and 46V in a search for a Jπ = 0− isomer. The possible production of the isomer was probed by searching for long-lived β+-and γ-ray activities. For each nucleus our results indicate that the yield of a 0− isomeric state is < 10−3 of that for the ground state.
The vibrational Raman spectrum of compressed solid hydrogen
Authors: Allin E. J. , Till S. M.
Published: April 2011

The frequencies of the pure vibrational lines, Q(0) and Q(1), in the Raman spectrum of solid H2 have been measured when the solid was subjected to a number of pressures between 400 and 1000 kg cm−2, corresponding to solid densities up to ~ 1250 amagat. Most samples studied had orthohydrogen concentrations ≥ 0.60. For these the frequency of Q(0) increased as the density increased but that of Q(1) showed little change. This can be explained if it is assumed that (i) the isotropic repulsive overlap interaction between a pair of molecules increases more rapidly than the attractive dispersion-type interaction, (ii) the effect of vibrational coupling between molecules in the same J-state increases asp2, and (iii) the lowering of the excitation energy of the ν = 1,J = 1 stale by electric quadrupolar interactions increases as ρ5/3. There is evidence that at higher densities ordering of the molecular angular momenta may occur at temperatures up to 4 K. The intensity of Q(1) relative to Q(0) is further enhanced at higher densities.
Existence of partial-wave two-cluster atomic scattering amplitudes
Authors: Nuttall J. , Singh S. R.
Published: April 2011

It is shown, with some restrictions, that two-cluster partial wave scattering amplitudes for atomic systems whose particles interact via two-body Coulomb potentials exist almost everywhere in the energy range below any three-cluster threshold. The method of proof is to reduce the problem to a coupled channel potential scattering problem with pseudo-local potentials. Boost analyticity is used to derive the pseudo-locality.
A comparison of radiation damage in Al by channeled and random beams of 0.6 MeV He+ ions
Authors: Swanson M. L. , Offermann P. , Ecker K. H.
Published: April 2011

The trapping rate of self-interstitial atoms at Ag solute atoms in an Al–0.05 at.% Ag crystal at 70 K was determined by channeling measurements. It was found that the trapping rate (and thus the radiation damage) caused by a channeled beam of 0.6 MeV He+ ions was equal to the trapping rate caused by a randomly aligned beam multiplied by the normalized yield of backscattered ions from Al atoms.
Cluster production in hadron–nucleus interaction at cosmic-ray energies
Authors: Ghosh Dipak , Naha Sadhan , Roy Jaya , Bhattacharjee Anuradha , Roy Topen
Published: April 2011

This paper presents a first investigation of the cluster production in nucleon – heavy nucleus collision in emulsion at cosmic ray energies (up to 1 TeV) following a model independent method proposed in a recent paper by Shivpuri and Gupta. It has been observed that the maximum charged pions constituting a cluster is three up to this energy and cluster characteristics are the same as in the case of nucleon–nucleon interaction in the same energy region.
An optical model for composite nuclear scattering
Authors: Wilson J. W. , Townsend L. W.
Published: April 2011

An effective potential operator, previously derived from a multiple-scattering series expansion of the exact transition amplitude for scattering two composite particles, is used in a high energy context to derive an approximate one-body Schrödinger equation by use of the closure approximation. The equivalent one-body equation is reduced to a set of coupled-channel equations which relates the entrance channel to the final excited states of the projectile and target. A Schrödinger equation for the coherent elastic amplitude is extracted from the coupled equations. Total and absorption cross sections are then derived on the basis of the Eikonal approximation and the assumption that the coherent scattering dominates the forward scattered amplitude. Unlike other models, the assumption that nuclear matter single-particle densities can be represented by nuclear charge distributions is not made. Instead, a method for extracting single-particle density distributions from nuclear charge distributions is presented. Comparisons with other theoretical models and with recent experimental data are also made. Finally, an experimental method for choosing between the Glauber approximation and the theory presented here is suggested.
On a mosaic graphite spectrometer without collimators
Authors: Koumelis C. N. , Londos C. A. , Kavogli Z. I. , Leventouri D. K. , Vassilikou A. B. , Zardas G. E.
Published: April 2011

An X-ray spectrometer was constructed for the detection of very weak lines having a large energy shift from the primary (Rayleigh) line. The spectrometer has no collimators and uses a graphite mosaic crystal as an analyser. The dependence of the resolution and intensity on one another is examined and both are calculated as a function of the scatterer–analyser distance. The spectrometer was tested in X-ray inelastic scattering experiments.
Phase transitions in finite systems
Authors: Pathria R. K.
Published: April 2011

Mathematical singularities, which are known to be at the heart of phase transitions and are responsible for making the thermodynamic functions of the given system nonanalytic, are a consequence of the thermodynamic limit, viz. N and V → ∞ with N/V staying constant. When a system containing a finite number of particles and confined to a restricted geometry undergoes a phase transition, these singularities get rounded off, with the result that all thermodynamic functions become analytic and vary smoothly with the relevant parameters of the problem. Theoretical analysis of such situations requires the use of special mathematical techniques which may vary drastically from case to case.In the present communication we report the results of a rigorous analysis of the problem of "Bose–Einstein condensation in restricted geometries", which has been carried out by making an extensive use of the Poisson summation formula. Particular emphasis is laid on the growth of the condensate fraction [Formula: see text] as the temperature of the system is lowered, and on the influence of the boundary conditions imposed on the wave functions of the particles. The relevance of these results, in relation to the scaling theory of finite size effects, is also discussed.
Multiplicity distributions in proton–neutron interactions at 400 GeV/c
Authors: Bhattacharjee D. K. , Ray S. K. , Sarkar P. , Roy T.
Published: April 2011

We present a study on the charged multiplicity distribution in proton–neutron (pn) interactions at 400 GeV/c from the data on an exposure of a Fermilab 30-in. deuterium bubble chamber to 400 GeV/c protons. The pn and pp distributions were extracted through an empirical model to correct for double scattering in deuterium. The overall average fraction of the double scattered event is 0.128 ± 0.011. The resulting pn and pp multiplicity distributions give average multiplicities of 8.48 ± 0.10 and 8.99 ± 0.12 respectively. The fraction of pd events which occur off the neutron is 0.52 ± 0.02. The extracted pp distribution parameters are compared with those from the hydrogen bubble chamber (HBC) experiments. Distinctive features of extracted pn distribution are discussed.
Application of the inverse scattering transform method to SBBS in an inhomogeneous medium: the Zakharov–Manakov solution
Authors: Enns R. H.
Published: April 2011

The inverse scattering transform method has been applied to the stimulated Brillouin backscattering (SBBS) interaction in a weakly spatially inhomogeneous medium. Specifically, the Zakharov–Manakov problem has been solved for examples of both an amplifier and a generator experimental setup yielding the complete spatial and temporal evolution of the light pulses involved. The structure of the resulting pulse shapes is discussed and the results compared with those in the literature.
Selective properties of overcoated copper granular films
Authors: Damaskinos Savvas , Girouard Fernand E. , Truong Vo-Van
Published: April 2011

Granular copper films were formed by thermal evaporation of copper onto glass substrates maintained at 300 °C. They were subsequently overcoated at room temperature with a thick layer of aluminium having a thickness of ~100 nm. The optical properties of the overcoated films have been studied in the spectral region from 0.3 to 1.0 μm. Results indicated that the granular films preserved their aggregate structure even after overcoating. Successive annealings showed a considerable lowering of reflectivity over this spectral range and suggested the potential use of such a system of overcoated granular films for solar energy collection.
Critical region ultrasonsic attenuation in the condensed inert gases
Authors: Cowan J. A. , Leech J. W.
Published: April 2011

New measurements in the range 5–15 MHz are reported for Kr and Xe along the saturated vapour pressure (SVP) line and the critical isochore. Analyzed together with previous 55 Mz measurements the results indicate a limiting high frequency corresponding states behaviour in which both the attenuation and those parts of the measurements associated with bulk viscosity and critical point effects show simple inverse power law dependence on [Formula: see text].
Photodisintegration of and radiative capture to the A = 2, 3, and 4 nuclei
Authors: Cameron J. M.
Published: April 2011

The experimental data for photodisintegration of and radiative capture to light nuclei are reviewed. Comparisons with recent theoretical calculations are used in attempts to identify areas where further experimental work would be most beneficial.
A study of radiative and collisional decay of Pb atoms by time-resolved laser spectroscopy
Authors: Giers D. H. , Atkinson J. B. , Krause L.
Published: April 2011

The 6p7s[Formula: see text] state of atomic Pb was populated by irradiation of Pb vapor by the frequency-doubled output of a pulsed nitrogen laser–pumped dye laser at the resonance wavelength λ = 2833 Å, and the resulting fluorescent decay was monitored using the method of delayed coincidences. A least squares fit to the observed time-decay spectrum yielded the decay constant and gave the radiative lifetime of the [Formula: see text] state, τ = 5.85 ± 0.20 ns. The dependence of the decay constant on buffer gas pressures was also investigated, yielding the total depopulation (quenching) cross sections Q = 0.31 ± 0.10 Å2 and 12.2 ± 1.0 Å2 for collisions with H2 and N2, respectively. An upper limit (Q < 0.2 Å2) for the He quenching cross section was also determined.
Comments on the analysis of proton decay
Authors: Karl Gabriel , O'Donnell Patrick J.
Published: April 2011

We discuss some general features of proton decay. The effect of nuclear matter on the decay rate of a proton into a positron and neutral pion is estimated. The general analysis of proton-decay branching ratios starting from a complete set of operators proposed by Weinberg, Wilczek, and Zee is described. A graphical technique to evaluate amplitudes is discussed in detail. Constraints on resulting branching ratios are also described.
On capillary waves in the gradient theory of interfaces
Authors: Sobrino Luis de , Peternelj Jože
Published: April 2011

We have solved the equations of motion for an inhomogeneous, nondissipative fluid linearized about a two-phase solution in order to determine the dispersion relation for capillary waves of long wavelength. The solution is reasonably rigorous in that no physical assumptions have been introduced. We find that, in accordance with the results of Turski and Langer and contrary to other workers' claims, the dispersion relation agrees with classical capillary theory only if thermal effects are included.
Jumping particle model. Critical slowing down near the bifurcation points
Authors: Franaszek M. , Pierański P.
Published: April 2011

A critical behaviour of the relaxation time of a simple nonlinear dynamical system is studied both experimentally and numerically. A critical exponent is introduced and determined.
A new model for the lattice dynamics of Zn–Cd chalcogenides
Authors: Ram R. K. , Kushwaha S. S. , Singh S. P.
Published: April 2011

A noncentral second neighbour ionic model is proposed for calculating frequency wave vector dispersion relations for the normal modes of vibrations for zinc and cadmium tellurides crystallizing in the zinc blende structure. The model takes into account the change in energy owing to rotation of bonds. The calculated phonon frequencies show a reasonably satisfactory agreement with the available optic data.
The current distribution on a circular disc
Authors: Kristensson Gerhard
Published: April 2011

In this paper we derive the surface-current distribution on a perfectly conducting circular disc. The current is obtained by calculating the limit of the surface currents on an oblate spheroid as the thickness goes to zero. The null-field approach is used. We show that it is possible to calculate all quantities in terms of the spherical basis functions, thus avoiding the cumbersome spheroidal basis functions. Furthermore, it is shown that the correct edge behaviour appears very naturally within the formulation. We compute the surface field on the disc for a plane incident wave, the surface current (eigencurrents) at the complex resonances of the disc, and the induced current on a subterranean disc excited by a circular antenna loop on the ground.
Diode laser measurements of N2-broadened line widths in the ν1 band of OCS
Authors: Mouchet A. , Blanquet G. , Herbin P. , Walrand J. , Courtoy C. P. , Bouanich J. P.
Published: April 2011

A tunable diode laser spectrometer has been used to perform measurements of pressure-broadening coefficients for 20 vibration–rotation lines in the ν1 band of 16O12C32S perturbed by N2. Calculations of these broadening coefficients have been carried out on the basis of the Anderson–Tsao–Curnutte theory and by considering an improved semiclassical impact theory.
The emitter-injection efficiency and emitter effective surface-recombination velocity in polysilicon emitter transistors
Authors: Halen P. Van , Camporese D. S. , Pulfrey D. L.
Published: April 2011

Measurements of the emitter-injection efficiency and calculations of the emitter effective surface-recombination velocity are reported for polysilicon emitter transistors, i.e., bipolar transistors with a polysilicon–insulator tunnel-junction contact to the emitter. It is demonstrated that the emitter-injection efficiency increases significantly and the emitter effective surface-recombination velocity decreases by two orders of magnitude when a thin insulating layer is deliberately grown between the monocrystalline emitter surface and the polycrystalline contact.
A triple-drain MOSFET magnetic-field sensor
Authors: Nathan A. , Huiser A. M. J. , Baltes H. P. , Schmidt-Weinmar H. G.
Published: April 2011

The two-dimensional distributions of the potential, current, and surface charge for a magnetic-field-sensitive N-channel MOSFET have been computed numerically. The MOSFET is operated in the linear region and is based on a triple-drain configuration. The sensitivity as well as the signal-to-noise ratio is studied for a variety of channel geometries, and an optimal device geometry is presented.
Rigorous solution of multiply fed dipole antenna
Authors: Ragheb H. A. , Hamid M.
Published: April 2011

This paper presents an extension of Hurd's solution for the input admittance of a long linear antenna to the general case of an arbitrarily and multiply fed dipole antenna. Accurate expressions for the radiation pattern, current distribution, and input admittance of the arbitrarily fed dipole antenna are derived by the Wiener–Hopf technique. The results are compared with Harrington's solution for the case of an arbitrarily fed dipole and very close agreement is observed. For a multiply fed dipole, a comparison with Strait and Hirasawa indicates that our expression for the radiation pattern is highly accurate, even when it only corresponds to the first-order expression of the current distribution. The current distribution and the input admittance are calculated up to the third order and include terms of O(1/h2), where h is half the tip-to-tip length of the antenna.
A radio jet associated with the symbiotic star CH Cygni
Authors: Seaquist E. R. , Taylor A. R.
Published: April 2011

We present observations that show that the symbiotic star CH Cygni recently underwent a strong radio outburst that produced a radio-emitting thermal jet. The jet is two-sided and is expanding lengthwise at an observed rate (end to end) of 1 arcsec/year, corresponding to a transverse velocity of 1100 km∙s−1 in each direction. The electron density on January 22, 1985 exceeded 2 × 106 cm−3, and the mass of the (ionized) gas exceeded [Formula: see text]. The emergence of the jet coincided with a decline in the visual luminosity of [Formula: see text].The data are consistent with a jet produced by supercritical accretion in a binary containing a red giant and a [Formula: see text] white dwarf. The discovery of a jet in such a system provides confirming evidence of the role played by accretion in determining the optical and radio properties of this system. It is also the first expanding jet found to be associated with an evolved stellar object.
Classical energy emission by a point dipole
Authors: McKeon G. , Shadwick B.
Published: April 2011

The classical Larmor formula [Formula: see text] for the energy-emission rate R of a point particle with charge e moving with acceleration aλ is extended to include the energy-emission rate of a point dipole whose dipole moment is characterized by a spacelike vector sα.
Quantum-field theory and the dynamical generation of quark masses
Authors: Elias V.
Published: April 2011

The dynamical generation of quark masses is discussed in terms of quark–antiquark, gluon–gluon, and quark–antiquark– gluon condensates. The quark–antiquark condensate is shown to contribute in a gauge-invariant manner to the dynamical quark mass. Arguments are put forward to suggest that the other condensates contribute only to the wave-function renormalization of the quark field and not to the magnitude of the dynamical quark mass.
Testing the surrogate zeta-function method
Authors: Chodos Alan , Myers Eric
Published: April 2011

Use of the surrogate zeta-function method was crucial in calculating the Casimir energy in non-Abelian Kaluza–Klein theories. We establish the validity of this method for the case where the background metric is (Euclidean space) × (N sphere). Our techniques do not apply to the case where the background is (Minkowski space) × (N sphere).
Study of wavelength dependences of target implosion at the Institute of Laser Engineering, Osaka
Authors: Nishimura H. , Azechi H. , Daido H. , Takabe H. , Mima K. , Nakai S. , Yamanaka T. , Kato Y. , Izawa Y. , Mochizuku T. , Yamanaka C.
Published: April 2011

The fundamental physics and relevant experimental data studied at the Institute of Laser Engineering, Osaka University, are discussed on the subject of laser-wavelength dependence. The main items are (i) absorption, (ii) heat transport and target ablation, (iii) preheating, and (iv) implosion uniformity. Short-wavelength lasers are hopeful candidates for fusion drivers owing to high coupling efficiencies and low preheating.
Sorption of water investigated with the photoacoustic effect
Authors: Korpiun P. , Herrmann W. , Kindermann A. , Rothmeyer M. , Büchner B.
Published: April 2011

Water adsorbed in the bulk of a sample essentially modifies the heat capacity, thermal conductivity, and, therefore, the transport of heat. At small concentrations of adsorbed water, this effect governs the photoacoustic (PA) signal measured in a gas–microphone cell. At higher concentrations, temperature-induced periodical adsorption and desorption mainly determine the PA signal. This effect is described formally by extending a model of oscillating mass diffusion, developed earlier to explain the photoacoustic effect on liquids, to the process of sorption. Its contribution to the PA amplitude is proportional to the sorption isotherm multiplied by the heat of sorption. Measurements with zeolite as an adsorbent in equilibrium with water vapour confirm the model. In addition, qualitative measurements on a sheet of brass, on filter paper, and on pine wood are included.
The thermal-wave lens
Authors: Burt J. A.
Published: April 2011

Ray diagrams have been calculated for a thermal-wave lens. Focussing is evident provided diffraction effects can be reduced. A practical use of the thermal lens is to scan for defects in a sample material along the focal plane of the lens.
Detection of plasmon surface polaritons on periodic silver gratings with a pyroelectric calorimeter
Authors: Grygier R. K. , Knoll W. , Coufal H.
Published: April 2011

Plasmon surface-polariton resonances of corrugated periodic silver surfaces are studied with a pyroelectric calorimeter. The shift of these resonances due to adsorbates and thin dielectric films is observed.
Rapid-scanning Fourier-transform infrared spectroscopy with photothermal beam-deflection (mirage effect) detection at the solid–liquid interface
Authors: Palmer Richard A. , Smith Matthew J.
Published: April 2011

Photothermal beam-deflection (mirage effect) detection in the mid-infrared with a commercial scanning Fourier-transform infrared spectrometer has been used to characterize various solid–liquid interface and surface-bound species. The inherently unfavorable ambient noise level and relatively high Fourier (photothermal modulation) frequencies associated with commercial scanning instrumentation are compensated by the thermal and refractive properties of the liquid beam-deflection medium, which enhance the signal. Preliminary results described illustrate the potential of the technique for infrared (IR) studies of electrochemistry, catalysis, corrosion, and other surface modifications, as well as for polarized IR single-crystal spectra.
Time-resolved derivation of heat fluxes from quantitative infrared thermography and its relationship to photoacoustics
Authors: Bein B. K.
Published: April 2011

Part of the plasma power losses in magnetic-confinement-based nuclear-fusion devices is deposited on limiters or divertor targets. This part can be deduced quantitatively from time- and space-resolved infrared (IR) surface-temperature measurements at the limiter or divertor targets by solving the heat-conduction equation of the target plate with the help of inversion solutions for the incident heat flux. This quantitative application of IR thermography and photoacoustic or photothermal frequency-dependent measurements are related, complementary techniques. Photoacoustics provides the means to measure the relevant thermal properties, i.e., the value of the effusivity (kρc)1/2 of the target plate, necessary for the quantitative interpretation of the thermographical measurements.