bluuebunny/crossref_metadata_2025 huggingface dataset:
WAVE PROPAGATION IN A PLASMA WITH ANISOTROPIC PRESSURE
Authors: Sharma S. R.
Published: April 2011

Wave propagation in an unbounded, magnetoactive, one-component plasma is considered with the help of modified Burgers equations. The pressure is assumed to be anisotropic and the effect of collisions on the wave propagation is examined. New modes of propagation have been reported in which the magnetic field and pressure anisotropy play an important role, while the electrostatic forces are comparatively less important. For the collisionless case, under certain conditions, new resonances appear in the transverse wave propagation, the resonant frequency being dependent upon the anisotropy parameter β. Cases have been pointed out where spatial instabilities may occur for certain values of β and the collision frequencies. It is further shown that the collisions may also offset the velocity–space instabilities which occur in a plasma with anisotropic pressure.
SUR L'APPROXIMATION DES BOSONS ET L'ANTISYMÉTRIE
Authors: Simard P. A.
Published: April 2011

A method is presented in the scheme of the boson approximation such that the antisymmetry between the quasi-particles is introduced naturally. Based on the transcription of the quasi-particle into the ideal space, the method enables one to give a unified description of the anharmonic corrections in the even–even and odd spherical nuclei.
ABUNDANCE ANOMALIES PRODUCED BY NUCLEAR REACTIONS IN STELLAR SURFACE LAYERS: I. NUCLEAR-REACTION RATES
Authors: Brancazio P. J. , Gilbert A. , Cameron A. G. W.
Published: April 2011

A preliminary investigation of the effects on abundances in stellar surfaces of extensive nuclear bombardment required the calculation of more than 105 nuclear-reaction cross sections. It was necessary to develop simplified methods for using the statistical theory of nuclear reactions to make these calculations in order that the computer time should not be prohibitive. These methods are described here and the results are compared with experiment. The accuracy of the calculations is, in general, about as good as, or somewhat better than, that obtained in previous applications of the statistical theory, probably because the use of an accurate level density formula outweighed the crudity of other approximations.
FINE STRUCTURE OF 3Σ− AND 3Π STATES OF NH, OH+, PH, AND SH+
Authors: Horani M. , Rostas J. , Lefebvre-Brion H.
Published: April 2011

A semi-empirical calculation of the fine structure of the 3Σ− ground states of several diatomic hydrides gives results in very good agreement with experiment. The Λ doubling of the 3Π0 first excited state, for J = 0, is shown to result from the algebraic sum of the spin–spin contribution and the spin–orbit interaction with Σ states. For the NH radical, the former effect predominates. For heavier molecules, the spin–orbit contribution dominates and the sign of the Λ doubling is reversed.The positions of the 3Π rotational levels do not agree with Gilbert's formulae. The apparent shift is interpreted by a simple model. In addition to the perturbation by the lower lying 3Σ− and 1Σ+ states and by a higher lying 1Π state, one must take into account perturbation by the lower lying 1Δ state. The values of the parameters obtained from fitting the experimental data support this interpretation.
PHOTOLUMINESCENCE IN CdS ASSOCIATED WITH NITROGEN IMPURITIES
Authors: Nyberg D. W. , Colbow K.
Published: April 2011

In the photoluminescence spectrum of cadmium sulfide, new emission bands have been produced which can be attributed to nitrogen impurities giving rise to acceptor levels 131 meV above the top of the valence band.
COMPUTATION OF EQUILIBRIUM CONFIGURATIONS OF DISSOCIATED JOGS IN F.C.C. CRYSTALS
Authors: Jössang Torstein
Published: April 2011

Extensions and the activation energies necessary for the constriction of dissociated jogs are calculated in the piecewise-straight dislocation segment model. Because the energy of the stair-rod pair in the jog is quite uncertain, the results are presented in such a way that one may predict jog extensions and activation energies as a function of the stair-rod energy. The energy of a stair-rod pair is estimated from experimental results on vacancy energies. The results indicate a considerable variation in the activation energy for different materials. For silver it is almost an order of magnitude larger than for copper and gold, which materials in turn have a considerably higher activation energy than aluminium and nickel.
ELECTRON PARAMAGNETIC RESONANCE OF MANGANESE IN CESIUM AND AMMONIUM CHLORIDES
Authors: Forman A. , Wyk J. A. Van
Published: April 2011

The spin-Hamiltonian parameters describing the EPR spectrum of Mn2+ in CsCl crystals grown from solutilon have been determined. The line-width data are in agreement with the manganese ions being incorporated interstitially rather than substitutionally for Cs+ ions. From the work on Mn2+ in NH4Cl we infer that the fine structure parameter, D2, is negative.
BOUNDS ON ATOMIC DIPOLE POLARIZABILITIES
Authors: Cohen M.
Published: April 2011

Rigorous lower bounds and effective upper bounds on the dipole polarizabilities of a number of S-state atoms and ions have been calculated from the oscillator-strength sum rule. Where comparison data are available, the present results are in good agreement with the most accurate values known.
EVOLUTION OF STARS OF LOW MASS
Authors: Ezer Dilhan , Cameron A. G. W.
Published: April 2011

Evolutionary sequences of models in the early and main sequence stages have been constructed for stars in the mass range [Formula: see text] with a composition X = 0.739, Z = 0.021. The general behavior of the evolutionary track in the Hertzsprung–Russell diagram is similar to that obtained for medium-mass stars. The [Formula: see text] star reaches the main sequence in 4 × 108 years, with a radiative core covering about half of the mass. The [Formula: see text] star develops a radiative core before reaching the main sequence in 8.5 × 108 years, but with the onset of thermonuclear reactions the energy generation is strong enough to cause the central radiative region of this star to become convective again. The [Formula: see text] star reaches the main sequence as a wholly convective star in 1.7 × 109 years. During the evolution of the [Formula: see text] star, the maximum central temperature attained is 4 × 106 °K, which is not sufficient to stabilize the star on the hydrogen-burning main sequence. Therefore, as contraction continues, the star contracts towards the white dwarf configuration.
A COMPLETE THERMODYNAMIC ANALOGY FOR TRANSPORT PROCESSES
Authors: Tomkoria B. N. , Scheidegger A. E.
Published: April 2011

A previously established analogy between thermodynamics and mass dispersion phenomena is extended to all thermodynamic functions and to steady-state processes. A detailed analysis is made of the pertinent thermodynamic equations and their corollaries in mass-based statistical mechanics. The analogue of the Carnot cycle is investigated. Applications to porous-media hydrodynamics and turbulent energy flow are presented.
AN INTENSITY ANOMALY IN THE RAMAN SPECTRA OF SOLID AND LIQUID HYDROGEN AND DEUTERIUM
Authors: Rosevear A. H. Mckague , Whiting G. , Allin Elizabeth J.
Published: April 2011

In the absence of molecular interaction the ratio of the intensity of the Q1(1) to that of the Q1(0) vibrational line in the Raman spectrum of solid hydrogen should be equal to the ratio of the number of ortho to the number of para molecules. The measured ratio at 2 °K has been found to be two to three times greater than this (Soots et al. 1965). The same anomaly is shown to be present at ~13.5 °K and also in the spectrum of the liquid. In the spectrum of solid deuterium the anomaly is much greater; the intensity ratio varies from 9.3 times the number ratio for n-D2 to 50 times the number ratio for 3.7% para-D2. The S1(0) and S1(1) lines do not show any corresponding anomaly. The experimental observations can be explained by the theory of vibrational interaction between ortho and para molecules developed recently by James and Van Kranendonk (1967a, b).
RADIATION FROM AN ELECTRIC DIPOLE IN AN AXIALLY MAGNETIZED PLASMA COLUMN—DIPOLAR MODES
Authors: Yip G. L. , Seshadri S. R.
Published: April 2011

The radiation characteristics of an electric dipole are investigated for the case in which it is situated on, and oriented perpendicular to, the axis of an infinitely long and axially magnetized column of uniform, lossless, and cold plasma. In general, the electric dipole will excite space waves as well as guided waves, both of which are dipolar in nature. The radiation power pattern and the radiation resistance, resulting from the space waves, are investigated as a function of the column radius, the signal frequency, and the strength of magnetization. For thin and isotropic plasma columns, the radiation resistance has a maximum, which is due to the dipolar resonance. This resonance occurs at 1/√2 times the plasma frequency. The introduction of anisotropy by the application of an axial magnetic field results in the splitting of the single dipolar resonance into two, occurring at frequencies below and above 1/√2 times the plasma frequency. Finally, a comparison is made between the radiation characteristics in the present problem and those due to an axially oriented dipole.
THE EMISSION SPECTRUM OF THE PbBr MOLECULE
Authors: Lal K. M. , Khanna B. N.
Published: April 2011

The emission spectrum of the A–X system of the PbBr molecule in the region 4 600–5 900 Å has been obtained in the second order of a 21-ft concave grating spectrograph (15 000 lines per inch) with a dispersion of 1.25 Å/mm. A rotational analysis of four bands—(3, 2), (2, 2), (3, 1), and (4, 1)—of this system has been done, leading to the determination of the following rotational constants:[Formula: see text]The system appears to be similar to the A-X system of the PbCl molecule in the visible region, and a [Formula: see text] transition has been suggested.
ELECTROMAGNETIC WAVE PROPAGATION OVER A NONPARALLEL STRATIFIED CONDUCTING MEDIUM
Authors: Schlak G. A. , Wait James R.
Published: April 2011

The objective is to calculate the electromagnetic field of a dipole located over a flat inhomogeneous ground whose upper layer has a variable thickness. Although a formally exact derivation for a lossy dielectric wedge model is available, its complexity prohibits immediate application. Instead, using a geometrical-optical technique, an approximate expression is developed for the effective surface impedance at the ground surface. This method takes full account of multiple reflections within the wedge region but neglects scattering from the wedge apex. Thus, the resulting surface impedance formula is valid everywhere except near the apex of the wedge. With this point kept in mind, the compensation theorem is employed to derive an integral equation for the electromagnetic field produced by a dipole located above this model of a nonparallel stratified ground. Using an appropriate reference field, the resulting integral equation of the Volterra type is solved by an iterative method. The excellent convergence of this procedure is demonstrated for a particular model. This solution yields quantitative results for the ground-wave attenuation function. In the case of a parallel stratified ground, it reduces to earlier known results.
THE ELECTRON-SCATTERING FACILITY AT THE SASKATCHEWAN ACCELERATOR LABORATORY
Authors: Katz L. , Beer G. A. , McArthur D. E. , Caplan H. S.
Published: April 2011

In this paper we describe the accelerator, beam handling system, magnetic spectrometer, and other equipment used to perform electron-scattering experiments. The nuclear information which can be obtained from such experiments is also discussed.
LOWER BOUNDS FOR THE BINDING ENERGIES OF N-PARTICLE SYSTEMS
Authors: Pruski S.
Published: April 2011

Two new families of lower bounds to the energy of an N-fermion system interacting via two-body forces are derived. They involve, respectively, energy levels of (N − 1)- and (N − 2)-particle systems associated with the given N-fermion system. The first is expected to give a fairly close approximation to the energy. In the case of an atom of nuclear charge Z with N electrons, the ground-state energy of this [Z, N] ion is bounded below by (N − 1)/(N − 2)2 times the sum of the N lowest energy levels of an associated ion [Z′, N′], with N′ = N − 1 and Z′ = Z(N − 2)/(N − 1).
RADIATION DAMAGE IN ZnO:Zn BY HEAVY IONS
Authors: van Wijngaarden A. , Hastings L.
Published: April 2011

ZnO:Zn phosphor samples were partially deteriorated by subjecting them to prolonged bombardment by energetic ions at energies below 110 keV. After the deterioration, the efficiency at the surface of the damaged phosphor was measured by means of low-speed heavy ions. The deterioration constant, C, is related to the efficiency, η, of the damaged phosphor, and to that η0, of the undamaged phosphor as[Formula: see text]where n is the irradiation dose. A relationship between the C value and the nuclear energy loss cross section for the damaging projectiles is derived. The relative magnitudes of the observed C values are in agreement with the measured nuclear energy loss cross sections for 40Ar and 14N.
ELECTROTRANSPORT IN SINGLE-CRYSTAL BISMUTH TELLURIDE
Authors: Dibbs H. P. , Keys J. D.
Published: April 2011

The movement of silver, gold, and copper in single-crystal bismuth telluride has been measured, parallel to the cleavage planes, as a function of temperature for two current densities. At the lower current density (150 A/cm2) movement occurred always to the cathode. At the higher current density (250 A/cm2) a transition occurred from cathodic movement below about 300 °C to bipolar movement—to both the anode and the cathode. This effect remained in evidence up to about 400 °C with an increasing tendency to anodic migration with increase of temperature. By about 400 °C essentially all transport occurred to the anode.The bipolar movement is considered to be due to the metal ions occupying two types of sites in the bismuth telluride lattice where different electrical forces are present.Similar experiments with iodine-doped bismuth telluride indicated negligible movement of iodine under comparable conditions.
THE ENERGY LOSS, THE DETERIORATION DEPTH, AND THE LIGHT OUTPUT FOR HEAVY IONS IN ZnO:Zn
Authors: Hastings L. , Wijngaarden A. van
Published: April 2011

Local regions on the surface of ZnO:Zn phosphor samples were deteriorated by a large number of low-energy ions. In this manner thin films which did not luminesce under ion bombardment were prepared. The phosphor samples were then scanned across energetic ion beams with sufficient energy to traverse the thin phosphor films. By comparing the luminescent response to this ion excitation in the damaged and undamaged portions of the phosphor surface, the total average energy losses of 1H, 4He, 14N, 40Ar, and 84Kr in passing through the films were determined. It was found that the energy losses for the heavier projectiles, when compared with the energy loss of hydrogen, are appreciably smaller than the energy losses predicted by the Lindhard and Scharff theory.The deterioration depth of the phosphor under prolonged bombardment is proportional to the speed of the damaging projectiles.
NEGATIVE PHOTOCONDUCTIVITY AND ELECTRICAL INSTABILITIES IN SEMICONDUCTORS
Authors: Jones B. L. , Beaudet P. R.
Published: April 2011

It has recently been suggested that the strongly nonequilibrium electron distribution created when monoenergetic electrons are optically excited into the conduction band in a semiconductor may give rise to a negative photoconductivity. That is, the direction of the photocurrent may become opposite to the direction of the electric field when the energy of the photoproduced electrons is a multiple of the longitudinal optical phonon energy. In this paper we use the self-consistent solutions of the Boltzmann transport equation and Maxwell's equations to study the stability of the system. We show that, if a situation of negative photoconductivity is attained, the system will become unstable if the magnitude of the photoconductance multiplied by 4π is larger than the inverse electron lifetime in the conduction band. In the absence of an external field there will then arise a photo-induced electric polarization of the medium. Under open circuit conditions the induced field grows to a value such that the nonlinear photocurrent reduces to zero. The system thus reaches a new steady state but supports the polarization field. If the photoconductor is connected to an external load, the induced field produces a nonvanishing current through the load.
ABSORPTION SPECTRA OF C3 AND C3H2 FROM THE FLASH PHOTOLYSIS OF DIAZOPROPYNE
Authors: Merer A. J.
Published: April 2011

The flash photolysis of diazopropyne (HC2∙CHN2) provides a particularly strong absorption spectrum of the free C3 radical. About 40 μs after the photolysis flash, the appearance of the [Formula: see text] (4 050 Å) system of C3 is similar to that obtained in the flash photolysis of diazomethane by Gausset, Herzberg, Lagerqvist, and Rosen, though much more intense. The intensity of the spectrum has permitted a study of the l-type doubling effect in the ground-state level 6ν2, of which the [Formula: see text] component has been found to lie at 458.2 cm−1. At shorter time delays [Formula: see text] the spectrum is complicated by bands arising from the levels ν1″ (1 224.5 cm−1) and 2ν1″ (2 436.0 cm−1).Below 3 700 Å the C3 spectrum is overlapped by absorption bands belonging to a new free radical, which has been identified from the intensity alternation in the rotational structure as the HCCCH radical. The vibrational structure of this system is exceptionally complex, and analysis has not been possible. The bands extend to about 3 100 Å, but are predissociated below 3 450 Å.
Investigation of the energy and temperature dependence of the string effect
Authors: Andersen J. U. , Uggerhøj E.
Published: April 2011

The temperature and energy dependence of the width of the axial dip in Rutherford scattering yield for energetic ions incident on a single crystal is investigated. The results are compared with numerical calculations on the basis of Lindhard's theory. In general, the agreement is quite satisfactory.A direct experimental demonstration of the reversibility rule is also presented.
Channeling of medium-mass ions through silicon
Authors: Eisen F. H.
Published: April 2011

The channeling of ions with [Formula: see text] through thin (0.24-1.5 μ) silicon samples has been studied for ion energies ranging from about 100 keV to 500 keV. The effects of radiation damage and sample misorientation on the energy spectrum and angular spread of the transmitted ions have been observed for [Formula: see text] channeling, using 11B projectile ions. Electronic stopping cross sections for well-channeled ions have been calculated from measurements of the maximum energy of the transmitted ions as a function of their incident energy. For 11B these measurements have been made for channeling along the [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] axes and between the {111}, {110}, and {100} planes. The value of the electronic stopping cross section, Se, for axial channeling ranged from 3.56 × 10−14 eV-cm2/atom for the [Formula: see text] axis to 4.88 × 10−14 eV-cm2/atom for the [Formula: see text] axis, at. an ion velocity of 1.5 × 108 cm/s. Se was significantly higher for the {111} plane than for the [Formula: see text] axis, but equal to Se for the [Formula: see text] axis. The values of Se for the [Formula: see text] and [Formula: see text] axes and the {110} plane were nearly equal. For ions other than 11B, Se was determined for [Formula: see text] channeling and was found to exhibit a strong oscillatory dependence on Z1. For electronic stopping cross sections calculated at an ion velocity of 1.5 × 108 cm/s, maxima in the Se vs. Z1 curve occurred at Z1 = 6 (Se = 4.34 × 10−14 eV-cm2/atom) and Z1 = 17 (Se = 6.76 × 10−14 eV-cm2/atom). The minimum occurred at Z1 = 11, where the value of Se, was 0.57 × 10−14 eV-cm2/atom.
The depth distribution of 40-keV 133Xe ions in various single crystals
Authors: Whitton J. L.
Published: April 2011

The marked difference previously observed in the depth distribution profiles of 40-keV 133Xe ions in the best channeling directions of tungsten and gold has prompted a more detailed investigation into the effect of various crystal properties on these profiles. We find that the major differences are: (i) a much smaller fraction of the ions remains channeled in gold; (ii) a maximum range is observable in gold at 20 °K but not at room temperature; and (iii) the maximum range in gold is much larger than in tungsten.The effects of crystal structure and of mean vibrational amplitude on the depth distribution have been studied. Depth-distribution profiles in gold resemble those in other similar f.c.c. metals, such as copper and aluminium. On the other hand, in iridium, an f.c.c. metal whose thermal vibrational amplitude is almost identical with that of tungsten and tantalum, the profiles resemble those in the b.c.c. metals much more closely than those in the f.c.c. metals.It is concluded that the mean vibrational amplitude of the lattice plays a major role in determining the depth-distribution profile, whereas the maximum range of channeled particles is determined mainly by the electron density along the mid-channel axis.
Thermal desorption of gas embedded in copper single crystals
Authors: Jokić T. , Perović B.
Published: April 2011

Thermal gas-release characteristics of copper single-crystal specimens bombarded by a high-energy Xe+ ion beam are presented. The influence of the crystallographic orientation of the targets bombarded, of the ion energy, and of the total ion dose was investigated. The ion energy ranged from 20 to 80 keV, and the total ion dose from 1013 to 1018 ions/cm2. Curves for fractional gas release were obtained by the method of stepwise thermal treatment, using the radioactive tracer technique. From the experimental data obtained and the theoretical expectations, corresponding activation energies for gas release were deduced. Thermal stability of the gas embedded in the target is discussed.
The dependence of the sputtering ratio of polycrystalline metals on the angle of ion incidence on the target
Authors: Evdokimov I. N. , Molchanov V. A.
Published: April 2011

The sputtering ratio of polycrystalline metals as well as the amount of ion beam energy reflected from the target surface showed angular behavior which was not monotonic at large angles of incidence. The simple model which takes into account "close-packing" at the target surface and, consequently, more or less ordered shadowing of the surface atoms seems to describe the experimental results qualitatively.
The induced infrared fundamental band of hydrogen dissolved in solid argon
Authors: Kriegler R. J. , Welsh H. L.
Published: April 2011

The induced infrared fundamental band of hydrogen dissolved (~1:100) in solid argon was studied with a 20-cm absorption path length at −191 °C. Transparent crystals were prepared by slow cooling of the liquid solution saturated with hydrogen at ~25 atm pressure. The H2 transitions, Q, S(0), and S(1), show similar patterns of five maxima, each of which can be analyzed as a zero-phonon line at the H2 frequency and summation and difference tones with lattice transition frequencies, 112 and 22 cm−1. The 112-cm−1 frequency is interpreted as arising from a localized lattice vibration involving an H2 molecule on a substitutional lattice site. Calculation from a model of an H2 molecule moving in the field of its argon neighbors, considered stationary, gave 109 cm−1 for this frequency. The origins of the zero-phonon lines and the 22-cm−1 lattice transition frequency are not so clear, and several possibilities are discussed. The H2 frequencies are shifted from their free-molecule values by the sum of a vibrational shift, Δνvlb = −17 cm−1, and rotational shifts corresponding to ΔB = −0.52 cm−1.
Free-carrier Faraday rotation in InAsxSb1−x alloys
Authors: Tongerloo Eric H. van , Woolley John C.
Published: April 2011

Room-temperature free-carrier Faraday rotation measurements in the wavelength range 6–25 μ and Hall-coefficient measurements have been made on polycrystalline n-type samples of InAsxSb1−x alloys of carrier concentration ~1017/cm3. Using these data and a Kane equation for the conduction band, values of the bottom of the band effective mass m0* have been determined over the whole alloy range. The results are compared with similar data from magnetothermoelectric power measurements and also with previously calculated data. From the m0* results, values of the square of the matrix element P2 have been calculated as a function of x.
Electrical properties of InAsxSb1−x alloys
Authors: Coderre William M. , Woolley John C.
Published: April 2011

Measurements have been made of the high-temperature Hall coefficient, electrical conductivity, and thermoelectric power in polycrystalline n-type samples of InAsxSb1−x alloys of extrinsic carrier concentration ~1017/cm3. From the Hall-coefficient data, values of the extrapolated absolute-zero band gap E00 have been determined over the whole alloy range, the thermoelectric power results being used to provide a correction factor to allow for effects of degeneracy. In all cases this correction was found to be very small. The resultant values of E00 for the alloys are somewhat lower than those obtained previously from optical absorption data and show a minimum of 0.17 eV at x ~0.4. From the electrical conductivity data, values of electron mobility μc have been obtained as a function of temperature T and composition x. At all temperatures in the range 0–500 °C, μc is found to vary linearly with x, indicating that the effects of alloy scattering are negligible. For each value of x, μc is found to satisfy the relation μc = μ0 exp (−T/θ), and the variation of θ with x has been determined.
Effects of sample rotation on de Haas – van Alphen oscillations
Authors: Vanderkooy J. , Datars W. R.
Published: April 2011

It is shown that the elastic compliance of a crystal mount, coupled with the sinusoidal nature of the de Haas – van Alphen torque versus magnetic field and angle, causes nonlinearities in the measured oscillations. The equations are formally the same as those describing the magnetic interaction in the de Haas – van Alphen effect. Hysteresis effects can result from the torque effects. Measurements of the torque de Haas – van Alphen oscillations in arsenic are in quantitative agreement with theory and the measured angular compliance of the torque magnetometer. Other effects of a compliant crystal mount are also discussed. The relative strengths of the torque effect and magnetic interaction are compared, and it is indicated by calculations for typical crystal mounts that torque effects may dominate unless care is taken to ensure a rigid sample mount.
The electronic isotope shift in the Lyman bands of H2, HD, and D2
Authors: Wilkinson P. G.
Published: April 2011

Five absorption bands in the [Formula: see text] transition of each of the molecules H2, HD, and D2 were obtained under high resolution in the 1050–1130 Å region in order to determine precise values of the electronic energy (Te) and the change (ΔTe) upon isotopic substitution. The fifth order of a 21-ft concave diffraction grating was employed. The experimental results are Te(H2) = 91 699.54 cm−1, Te(HD) = 91 698.88 cm−1, and Te(D2) = 91 698.83 cm−1. These reveal a surprisingly small shift (< 1 cm−1 in ΔTe) and show that the electronic energies (Te) are in remarkably close agreement (5.4–7.8 cm−1) with ab initio calculations.
The effect of an extranuclear electron on the muonic atom
Authors: Best B. G. , Kim D. Y.
Published: April 2011

The effect of an extranuclear electron on the hydrogenic muonic atom in the ground state has been evaluated by means of a variational method. The energy-level shift due to this effect was found to be about 0.5% of the total energy of the muonic atom.
Isotope shift studies of the high-pressure carbon bands
Authors: Dhumwad R. K. , Narasimham N. A.
Published: April 2011

High-pressure carbon bands have been excited in condensed discharges through CO containing about 40% enriched 13C and photographed on a 3.4-m Ebert grating spectrograph. The isotope shifts, ν 12C2–ν′ 12C13C, measured for the bands at 4368.8, 4680.2, 5899.3, and 6442.3 Å, agree with those calculated on the assumption that the bands arise from an initial level of ν′ = 6 and involve the 6–4, 6–5, 6–8, and 6–9 transitions of the A3Πg–X′ 3Πu system of C2.
First results from the Haverah Park 2-km EAS array
Authors: Earnshaw R. A. , Evans A. C. , Hughes R. R. , Reid R. J. O. , Tennent R. M. , Watson A. A. , Wilson J. G.
Published: April 2011

The form and mode of operation of the 2-km array at Haverah Park are described briefly. As a guide to the performance of tie whole array, which encloses an area of 11 km2, the pulses from a single satellite detector have been recorded on an oscilloscope triggered by the central 500-m array.It has been found that showers due to primary particles of energy > 1017 eV frequently give detectable signals at distances of up to 2.5 km from the shower axis. The lateral distribution function has been found to obey the same power law out to this distance as in the range 150–1 000 m from the shower axis. The existence of such pulses ensures a generous overlap between the showers detected efficiently by the 500-m and 2-km arrays. A large percentage of the pulses correspond to energy losses < 120 MeV and are probably due to a relatively intense flux of low-energy photons.Details of two showers having primary energies > 1019 eV are presented. A large radio pulse has been observed in coincidence with one of these showers.
The Kolar Gold Fields extensive air shower experiment
Authors: Chatterjee B. K. , Murthy G. T. , Naranan S. , Sivaprasad K. , Sreekantan B. V. , Suri A. , Viswanath P. R.
Published: April 2011

Measurements have been made on high-energy muons (>220 GeV and >640 GeV) in extensive air showers in the size range 105–107 particles. Results on the energy spectrum, lateral spread (for Eμ > 220 GeV), and the dependence of the total number of muons on the shower size are given. The relation between the number of muons (Nμ) and the shower size (N) can be expressed as[Formula: see text]Assuming an exponential lateral distribution of high-energy muons, the average lateral spread of muons of energy >220 GeV has been found to be ~40 m.The results are compared with the predictions of the calculations done by Murthy et al. (1967).
Study of extensive air showers at Mount Norikura. I. Measurement of lateral structure
Authors: Miyake S. , Hinotani K. , Ito N. , Kino S. , Sasaki H. , Yoshii H. , Sakuyama H. , Kato E.
Published: April 2011

The lateral density distribution of charged particles in EAS is one of the essential parameters for the analysis of individual EAS. To measure the lateral density distribution in detail, 100 ¼-m2 scintillators were arranged in a lattice configuration with a unit distance of 5 m or 2.5 m. The conventional EAS array of 20 scintillators was also used to obtain densities up to about 100 m from the center. These observations are much more accurate than those obtained previously, and it has been found that there are various types of structure functions which can be approximated by the functions for single cascades of age parameter from 0.6 to 1.6. It was difficult in some instances to fit the lateral distribution by a unique function, especially for small EAS.The two-dimensional map obtained by means of the above 100 detectors shows that individual EAS have rarely a complicated structure within a range of about 20 m from the axis. The results are discussed in relation to the character of high-energy interactions as well as to fluctuations in the development of EAS.
A study of the cores of air showers in the size range 104 to 107 particles
Authors: Bakich A. M. , Melley D. , McCusker C. B. A. , Nelson D. , Peak L. S. , Rathgeber M. H. , Winn M. M.
Published: April 2011

Results from the Sydney 64-scintillator array are reported. The array now uses logarithmic amplifiers with a range from 1 to 300 000 particles per square meter. This allows us to detect both higher and lower central densities than was previously possible. Further observations and comparison with Monte Carlo calculations confirm the previous result that air showers in the size range 104 to 5 × 105 particles are due to cosmic-ray primaries with much the same charge spectrum as at 1011 eV total energy.Showers of size greater than 106 particles seem mostly to be multicored (in agreement with previous results). The apparent transverse momentum is high and increases with shower size. The quantity rpL/n, which is a measure of the mean transverse momentum in very high energy interactions, is always greater than 1 GeV/c and increases with shower size. The existence and nature of a possible superstrong interaction are briefly discussed.
A Monte Carlo simulation of air shower cores
Authors: McCusker C. B. A. , Peak L. S. , Rathgeber M. H.
Published: April 2011

The electromagnetic and strongly interacting particle distributions falling on the Sydney 64 scintillator array for a variety of primary particles (from protons to iron) of a given incident total energy have been simulated using Monte Carlo and analytic methods. For a given primary particle, various fundamental nucleon–nucleon and pion–nucleon interactions have been tried. The results show that a number of characteristics–e.g. the average type of core structure (multiple or single), the mean maximum central electron density, and the mean maximum energy of a strongly interacting particle–are all strongly dependent on the nature of the primary. They are only weakly dependent on, or are independent of the nature of the fundamental interaction within the range covered.The results are compared with experimental results from the Sydney 64 scintillator array.
The electromagnetic structure of air shower cores at sea level
Authors: Böhm E. , Büscher W. , Fritze R. , Roose U. J. , Samorski M. , Staubert R. , Trümper J.
Published: April 2011

An analysis has been made of 2 400 shower cores observed with the 32-m2 neon hodoscope of the Kiel air shower experiment, yielding the following results:1. More than 99% of all showers show a more or less steep single-core distribution.2. The Δ/N distribution (Δ = central density, N = shower size) has a total width of about a factor of 10, showing no appreciable change in that width with increasing shower size in the interval ranging from N = 105 to about 107.3. Only a few double-cored events (4–9) have been found, all of them close to a shower size of 105 particles.4. On the basis of a Monte Carlo simulation of showers initiated by primary particles with different atomic weights, it is concluded that the hypothesis of observed multicored events being due to heavy primaries meets no serious difficulties. However, the cascade process and the associated fluctuations seriously reduce the number of subcores observable; and this reduction effect increases with atomic weight.
Fine structure of air shower cores observed with a spark chamber at 5 200-m altitude
Authors: Shibata S. , Saavedra O. , Kamata K. , Pointe M. La , Rennex B. , Uchino K. , Nagano M. , Suga K.
Published: April 2011

Spark chambers forming a 5-m2 array have been operated at the center of the Chacaltaya air shower array in Bolivia at an altitude of 5 200 m. Double-cored showers and steep-cored showers are observed, and a comparison is made with observations at sea level. The location of the electromagnetic core is compared with that of the nucleonic core.
Predominantly electromagnetic air showers of energy 1014 eV to 1016 eV
Authors: Kamata K. , Shibata S. , Saavedra O. , Domingo V. , Suga K. , Murakami K. , Toyoda Y. , Pointe M. La , Gaebler J. , Escobar I.
Published: April 2011

The Chacaltaya air shower array has continued to be used for the accumulation of muon-poor air showers in an attempt to find evidence of gamma rays in the primary cosmic radiation. A progress report is given here, and some upper limits to the intensities are presented for possible point sources and for galactic and isotropic backgrounds.
The fluctuations of Cerenkov radiation flashes caused by extensive air showers
Authors: Nesterova N. M.
Published: April 2011

The experimental data concerning the fluctuations of Cerenkov flashes in the atmosphere are analyzed to investigate the composition of primary particles for the energy range 1014–1016 eV.
The muon component of extensive air showers
Authors: Allan H. R. , Blake P. R. , Neat K. P. , Pidcock J. K.
Published: April 2011

The lateral distribution of the muon component of extensive air showers, and the variation in the total number of muons with shower size, have been studied for showers of sizes between 3 × 105 and 108 particles. The lateral distribution function is found to be in essential agreement with Griesen's formula, and the total number of muons is found to vary smoothly with shower size, as N0.75.
Fluctuations of the muon component in the central part of EAS
Authors: Gawin J. , Hibner J. , Maze R. , Wdowczyk J. , Zawadzki A.
Published: April 2011

The fluctuations of the muon component, at small distances from the axis, due to the development of EAS were found to be 0.34 ± 0.05. This value agrees well with the theoretical predictions of de Beer et al. (1967) when the effect of the negative correlation between Ne (shower size) and [Formula: see text] (average muonic radius) is taken into account. Different sizes of showers in seven groups were investigated (in the range from 2 × 105 to 1.2 × 106).
Study of extensive air showers at Mount Norikura. IV. Lateral distribution of muons for types of EAS
Authors: Miyake S. , Hinotani K. , Ito N. , Kino S. , Sasaki H. , Yoshii H. , Sakuyama H. , Kato E.
Published: April 2011

Muons accompanied by EAS have been observed by a neon hodoscope array 6 m2 in area placed 36 m from the center of the EAS array. The lateral density distribution function of muons and an average density at fixed distance are studied with respect to the size and age parameter of EAS. The EAS are in a size range of 106 to 107, and the muon density at distances of 15–55 m from the axis of EAS has been observed for muons which penetrate 20 cm of lead.Preliminary results obtained in this experiment are as follows: (1) The lateral density distribution of muons shows clear correlation with that of electrons: assuming the distribution function to be a power function of the distance from the axis, the exponent varies from steeper than −1.5 to flatter than −1.0 for younger and older EAS respectively. (2) The size dependence of muon density can be expressed as [Formula: see text], and is independent of the age parameter of EAS.
Investigation of the high-energy muons in EAS
Authors: Vernov S. N. , Vedeneev O. V. , Kalmykov N. N. , Nechin Yu. A. , Khrenov B. A. , Khristiansen G. B.
Published: April 2011

The results of the experimental study of the burst spectrum in ionization chambers underground accompanied by EAS are presented. The investigations were carried out at depths of 20 and 40 m.w.e. The absence of absorption of the burst intensity with increasing depth underground (from 20 to 40 m.w.e.) and the form of the burst spectrum make it possible to affirm that the bursts in EAS underground are generated by high-energy muons. The experiment shows that the 10–103 GeV EAS muon energy spectrum has an exponent γ = 1.2–1.5.
The charge ratio of muons in extensive air showers
Authors: Orford K. J. , Turver K. E. , Walton A. B.
Published: April 2011

The most probable height of production of muons of prescribed momenta is determined from their deflections in the geomagnetic field and is found to be in agreement with the predictions of recent EAS models. A large positive excess is found for the muons which are secondary to particles having high transverse momenta.
Properties of air showers and the nature of the primary cosmic-ray spectrum
Authors: Cowsik R.
Published: April 2011

Calculations of the longitudinal development of air showers initiated by protons and heavy primaries are made. A comparison of the characteristics indicates that the separation of the heavy nucleus and proton-initiated showers is difficult. The size dependence of the number of muons of energy greater than 1, 220, and 660 GeV is shown to be consistent with the existence of a rigidity cutoff of galactic cosmic rays at ~ 105 GV, followed by an extragalactic component of protons at higher energies. The lateral distribution of 220-GeV muons in air showers is shown to be consistent with a mean transverse momentum of less than 1 GeV per pion.
Calculations of average characteristics of EAS components and Monte Carlo calculations of their fluctuations using different models of nuclear interactions. I. Methodology—Lateral structure and transition curve of electrons
Authors: Murthy G. T. , Sivaprasad K. , Rao M. V. Srinivasa , Tonwar S. C. , Vatcha R. H. , Viswanath P. R.
Published: April 2011

Properties of extensive air showers are computed by two methods based on eight plausible models of ultra-high-energy interactions of nucleons and pions with air nuclei. The first method is the numerical solution of the diffusion equations describing the one-dimensional nuclear cascade, from which the average properties of nucleon-initiated showers of given energy are deduced. The second method is Monte Carlo simulation of the three-dimensional nuclear cascades from a sample of which typical shower properties and the extent of their fluctuations are estimated.1. For showers of size < 106, the deduced shower absorption lengths are consistent with experimental results only for models involving nucleon pair production.2. The accuracy of experimental results on the depth of the shower maximum at different primary energies (105–1010 GeV) available at present is insufficient to select any particular model.3. Monte Carlo size distributions for a given primary energy indicate that with the primary energy spectrum known at present, showers of a given size originate from primaries of a relatively narrow range.4. The electron lateral structure parameter, α, fluctuates considerably for showers of primary energy < 106 GeV; the spread decreases with the primary energy.5. The average value of α increases with primary energy up to 106 GeV and saturates at ~ 1.2 for showers of larger sizes.
Calculations of average characteristics of EAS components and Monte Carlo calculations of their fluctuations using different models of nuclear interactions. II. Muons
Authors: Murthy G. T. , Sivaprasad K. , Rao M. V. Srinivasa , Tonwar S. C. , Vatcha R. H. , Viswanath P. R.
Published: April 2011

The results pertaining to the muon component obtained in the calculations described in Part I are presented. The predicted lateral distributions and energy spectra of muons with energies above various thresholds are compared with experimental observations. Also presented are the expected variations of the number of muons with shower size compared with experimental results. None of the models assumed predict in every detail the results obtained experimentally. Modifications that could possibly be made are indicated.
Calculations of average characteristics of EAS components and Monte Carlo calculations of their fluctuations using different models of nuclear interactions. III. Nuclear-active particles
Authors: Murthy G. T. , Sivaprasad K. , Rao M. V. Srinivasa , Tonwar S. C. , Vatcha R. H. , Viswanath P. R.
Published: April 2011

Results concerning NAPs from calculations described in Part I are given here. (1) Nucleon-pair-producing models give results in agreement with the observed size variation, integral energy spectrum, and delay distribution of NAPs. (2) Fluctuations in NAPs are partly correlated to fluctuations in the electron lateral structure parameter. (3) A nonlinear size variation of low-energy NAPs is expected from a changing primary composition model. (4) The usefulness of ultra-high-energy neutral events, the number of NAPs, and core structure studies in distinguishing between proton and heavy primaries is discussed.
Monte Carlo studies on electromagnetic cascades in extensive air showers
Authors: Thielheim K. O. , Schlegel E. K. , Beiersdorf R.
Published: April 2011

Three-dimensional Monte Carlo calculations have been performed on the trajectories of high-energy hadrons in extensive air showers. The central electron density and gradient of distribution are obtained for individual electromagnetic cascades together with coordinates at the level of observation. Various assumptions concerning primary mass number and energy, distributions of strong interaction parameters, and fragmentation mechanisms are discussed with respect to the production of steep maxima of electron density by single electromagnetic cascades in the core region of extensive air showers.
Phenomenological characteristics of EAS at sea level: EAS size spectra and fluctuations of EAS
Authors: Vernov S. N. , Khristiansen G. B. , Abrosimov A. T. , Atrashkevitch V. B. , Beljaeva I. F. , Kulikov G. V. , Mandritskaya K. V. , Solovjeva V. I. , Khrenov B. A.
Published: April 2011

Experimental EAS spectra of sizes and muon numbers and results on the fluctuations of the electron–photon and muon EAS components at sea level are presented. In constructing size spectra the sizes of showers were determined by use of the individual lateral distribution function. Experimental data were obtained with considerably better statistics than in our previous works.
The electron angular distribution at various depths in cascade showers
Authors: Guzhavin V. V. , Ivanenko I. P. , Samosudov B. E.
Published: April 2011

An analytical solution of the angular problem to the approximation of middle angles which is valid for any angles of particle deviation in an elementary event of Coulomb scattering has been obtained using the approximate operator (Vaskin et al. 1966). The proposed method makes it possible to evaluate the accuracy of the resulting expressions and the contribution from non-multiple and multiple Coulomb scattering.
On the calculation of the electron angular distribution function in a shower under arbitrary boundary conditions
Authors: Bakhtadze A. K.
Published: April 2011

The solution of the equations of electromagnetic cascade theory to the approximation of small angles of multiple scattering under arbitrary boundary conditions is described.
The Harwell–Grove radio installation for detecting EAS at low elevation, over a 9 km base line
Authors: Charman W. N. , Fruin J. H. , Jelley J. V.
Published: April 2011

The paper describes an installation set up to investigate the problems of detecting EAS by wholly radio methods. This installation is divided between two stations 9 km apart. At each station local coincidences are taken between two large corner reflector antennas sited 130 m apart, the effective beamwidth in azimuth being ~ 30°. The Harwell station is operational and includes photographic recording of the radio outputs on 5 μs time bases, and considerable monitoring on chart recorders. The Grove station is at present only partially complete.Preliminary results obtained so far reveal that there are broadly three classes of events: (a) pulses which are strictly bandwidth-limited and are attributed largely to random coincidences from sky-noise; (b) pulses of duration ~ 200–400 ns which have steep rise and fall characteristics and which, like those in (a), are "single"; and (c) multiple pulses with fine structure for at least 5 μs. The events in class (b), which disappear when 1 μs delay is inserted in one channel, can possibly be attributed to EAS. The (c) pulses are suspected to arise from distant electrical storms.