bluuebunny/crossref_metadata_2025 huggingface dataset:
The derivation of transverse momenta from EAS observations
Authors: Beer J. F. de , Holyoak B. , Oda H. , Wdowczyk J. , Wolfendale A. W.
Published: April 2011

Observations on EAS are examined from the point of view of deriving the transverse momenta of the secondaries produced in ultra-high-energy collisions.The lateral distributions of muons for various threshold energies provide useful experimental data, and a detailed analysis of this characteristic has been made. The most extensive results have been reported by Earnshaw et al. (1967), and a theoretical treatment of the lateral distributions expected, as a function of the transverse momentum of the parent pions, has been given by de Beer el al. (1966). A comparison appears to indicate mean transverse momenta much greater than the value of ~0.4 GeV/c found in the more direct observations on nucleon–nucleon collisions. However, an examination of the fluctuations in lateral distribution expected theoretically suggests that there is bias with practical EAS arrays leading to the selection of that fraction of the showers having unusually flat lateral distributions.The effect of applying a correction to allow for this bias is to reduce the derived mean transverse momenta considerably; the values being ~0.6 ± 0.2 GeV/c for pion interactions of mean energy ~200 GeV and 1.0 ± 0.3 GeV/c for interactions of mean energy ~4 000 GeV. These values are still significantly higher than the values measured more directly.
Generation of cosmic rays during chromospheric flares and weak increases in the brightening of the sun
Authors: Aldagarova Kh. S. , Ivanov V. I. , Kolomeets E. V.
Published: April 2011

The changes in the neutron component of cosmic rays at times of chromospheric flares and small increases in the brightening of the sun are studied, using the data from the worldwide network of stations. It is shown that the generation of particles on the sun takes place both during chromospheric flares and during weaker processes. The energy spectrum of the additional particles changes during their motion in interplanetary space, depending on the electromagnetic conditions in the space. At solar minimum the dependence of the effect on the heliocoordinates of the flares is shown more clearly, both in amplitude and in decay time. This fact suggests that the interplanetary magnetic field has become more regular and undisturbed at solar minimum.
Diffusion of high-energy solar particles through interplanetary space
Authors: Kondo I. , Fujimoto K. , Nagashima K. , Oda H.
Published: April 2011

The effects of the interplanetary magnetic field on the propagation of solar cosmic-ray particles are studied. The presence of the quasi-stable magnetic field of garden-hose type found by satellite observations suggests that the movement of the particles along these lines of force is much easier than that perpendicular to them. The diffusion equation of the particles through such a medium is solved, and the number density of particles at the earth is computed for several values of parameters. The results of the computation concerning the dependence of the time of maximum density on the position of the source relative to the sun–earth line are compared with those obtained from observations. It is found that the diffusion coefficient perpendicular to the line of force is 1/10 to 1/20 of that parallel to the line for relativistic particles, while the ratio is 1/50 to 1/100 for lower-energy particles.
Directional measurements of the cosmic-ray daily variation at a vertical depth of 60 m.w.e. in London
Authors: Peacock D. S. , Dutt J. C. , Thambyahpillai T.
Published: April 2011

Semicubical telescopes pointing in the vertical direction and inclined cubical telescopes pointing in the east and north directions have been employed to measure the cosmic-ray daily variation at an underground site in London. Although the statistical accuracy of the measured daily variations is not very high, there are strong indications that during 1965, which was the year of maximum cosmic-ray flux associated with the last solar minimum, tire upper limiting rigidity of the corotation anisotropy (with time of maximum at 1800 h) was reduced to such low values that a Compton–Getting effect due to the motion of the earth around the sun became observable. Also, the atmospheric contribution to the measured solar daily variations appears to be very small. There is no evidence for an enhancement of the observable sidereal daily variation associated with the lowering of the upper limiting rigidity of the corotation anisotropy.
Investigation of the cosmic-ray east–west asymmetry
Authors: Bogomolov E. A. , Karakadko V. K. , Lubyanaya N. D. , Romanov V. A. , Totubalina M. G. , Yamshchikov M. A.
Published: April 2011

The east–west asymmetry has been measured to obtain a more accurate value of the antiproton–proton flux ratio in the primary cosmic radiation. The measurements have been carried out at middle latitudes at a depth of 10 g/cm2 of atmosphere and at a zenith angle of 60°. The telescope used for detection consisted of two scintillation counters, a lucite Cerenkov counter, and a gas Cerenkov counter. The threshold of the gas Cerenkov detector has been changed from 1.7 BeV to 5.2 BeV (for protons) in flight. For orientation of the device in space the earth's magnetic field was used.The preliminary results of the experiment are given.
Energetic solar particle propagation and the structure of interplanetary space
Authors: Vernov S. N. , Gortchakov E. V. , Logatchov Yu. I. , Lyubimov G. P. , Pereslegina N. V. , Tverskoy B. A. , Chudakov A. E.
Published: April 2011

This work studies the structure of interplanetary space between the orbits of Venus and Mars on the basis of solar proton streaming and cosmic-ray variations measured from Soviet and U.S. spacecraft. Solar proton fluxes measured from spacecraft at various distances from the sun and in various solar activity phases are intercompared. The problem of the large radial gradient of protons with energies of 1–5 MeV is discussed.
The cosmic-ray intensity variations with periods of 19-24 days
Authors: Bazilevskaya G. A.
Published: April 2011

Sporadic cyclic variations of the cosmic-ray intensity with periods of 19 to 24 days have been found from the results of balloon and neutron monitor observations. These variations were observed mainly in the years of high solar activity, 1958–62. They appeared to be caused by the general solar activity which, as our treatment has shown, undergoes similar cyclic variations (according to sunspot number or 10.7-cm radio-emissions). The variations under investigation appear with a lag of about 1.5 months compared with the solar-activity variations.
The acceleration of energetic particle fluxes in shock fronts in interplanetary space
Authors: Rao U. R. , McCracken K. G. , Bukata R. P.
Published: April 2011

On six occasions during 1966, enhanced fluxes of > 7.5-MeV energetic particles have been observed coincident with the onset of a Forbush decrease which was initiated by a solar flare. The anisotropic character of the particle fluxes indicates that the particles were not trapped and that particle acceleration was occurring in the region associated with the onset of the Forbush decreases. Subsequent to the onset of the Forbush decreases, bidirectional anisotropies of 7.5–45 MeV-protons were observed. It will be shown that these observations provide strong evidence for the shock-wave model for the Forbush decrease. It is suggested that particle acceleration in interplanetary shocks is a commonly occurring phenomenon, and, in particular, it is suggested that recurrent ≈1-MeV proton events are due to particle acceleration in corotating shock fronts.
Small-scale cosmic-ray fluctuations and their association with recurrent phenomena, October 1965 through April 1966
Authors: Bachelet F. , Dyring E. , Iucci N. , Villoresi G.
Published: April 2011

A method is developed for separating the diurnal variation from cosmic-ray data recorded by NM64 neutron monitors at high latitudes. It utilizes the negligible diurnal variation at the Alert station, which is verified by power spectrum analysis. The method offers the development of a "universal high-latitude diurnal wave" on a day-to-day basis, taking into account the asymptotic longitude differences between the stations.The period 15 October 1965 to 30 April 1966 is studied in connection with the space measurements of Pioneer VI.
Anisotropy of transient variations of cosmic-ray intensity
Authors: Wada Masami , Komori Hiroo
Published: April 2011

The angular distribution of the anisotropy of cosmic rays in interplanetary space is generally assumed to follow a cosine function. In the case of the daily variation, the source direction lies essentially in the equatorial plane. In the present calculation, the following three points were taken into account: (1) the latitude of the principal direction, (2) the angular distribution functions, and (3) the increases in flux of cosmic-ray particles. The response functions, the asymptotic directions, and the variation spectra are also involved in the calculation. Because of the rotation of the earth with respect to the source direction, which is fixed at the 12-h meridian, the daily variations are obtained. The variations include higher harmonics if the angular distribution is other than a simple cosine function.Comparing the calculated curves with observed data, the anisotropy in the space outside the geomagnetic field can be estimated with parameters such as the source direction in latitude and longitude, the half-width of the angular distribution, and the amplitude and exponent of the variation spectrum, which are all time-dependent. An increase which occurred on 24 March 1966 was analyzed.
Eleven-year modulation of galactic cosmic rays in interplanetary space
Authors: Chaeakhchyan A. N. , Charakhchyan T. N.
Published: April 2011

Almost the whole increase in the cosmic-ray intensity in the stratosphere during the period of decreasing solar activity (1960–64) was composed of a number of individual events occurring at intervals of 6–12 months. This phenomenon is almost entirely due to the corresponding decrease of solar activity (according to the sunspot number).Several interesting cases were found when solar-activity decreases to a new stationary level took place rapidly (within several days). After such events the cosmic-ray intensity gradually increased to reach a stationary level over a period of about two months. The time, tst, during which the cosmic-ray intensity in interplanetary space (after the above-mentioned events on the sun) approaches a stationary value is about 40, 60, and 80 days according to observations in 1961, 1963, and 1964 respectively.Some results have been obtained on the large-scale magnetic "clouds" which modulate the galactic cosmic rays in interplanetary space: (a) The velocity of propagation of these magnetic clouds is [Formula: see text]. According to the data on u and tst the radius of the sphere around the sun, r, within which the cosmic rays are modulated depends little on solar activity and is equal to 10–15 AU. (b) The density of magnetic clouds in space is either independent of the distance to the sun or decreases less rapidly than the inverse square law suggested by conservation of clouds.[Formula: see text]
Long-term variations of the primary cosmic-ray electron component
Authors: L'Heureux Jacques , Meyer Peter , Verma Satya Dev , Vogt Rochus
Published: April 2011

The intensity of primary cosmic-ray electrons has been measured from 1960 through 1966 at balloon altitude over Ft. Churchill, Manitoba. Initial measurements were made with an energy-loss vs. range counter telescope from 1960 through 1964. From 1964 through 1966 an energy-loss vs. total energy counter telescope was used. Overlapping data exist for both instruments in 1964. Our results are consistent with the absence of a solar modulation effect for electrons in the 0.25 to 1.05 BV rigidity range. The experimental errors lead to an upper limit of 60% for the possible fractional change of the electron intensity over this period.
Observation of the electron to alpha-particle ratio as a test for solar modulation
Authors: Bleeker J. A. M. , Burger J. J. , Deerenberg A. J. M. , Scheepmaker A. , Swanenburg B. N. , Tanaka Y.
Published: April 2011

The electron to alpha-particle ratio is a sensitive parameter for examining the mechanism of solar modulation. Our balloon-borne detector designed for the detection of primary electrons (0.5–30 GeV) can also register alpha particles with a rigidity above 1.7 GV. These alpha particles are selected from the recorded events unambiguously by means of an analysis of the simultaneous ionization losses in three plastic scintillators. Several balloon flights have been carried out from Kiruna, Sweden (geomagnetic cutoff 0.5 GV) in 1965 and 1966. Electron observations from flights in subsequent years do not indicate a significant modulation of electrons above 500 MeV, whereas the alpha particles show a modulation of 15 ± 3%. The results are not in agreement with a purely rigidity-dependent modulation mechanism.
Rigidity dependence and the correlation with solar activity of the 11-year variation
Authors: Hatton C. J. , Marsden P. L. , Willetts A. C.
Published: April 2011

The rigidity dependence of the modulation of the cosmic-ray intensity has been investigated using ground-based recorders during the period 1960–66. The intensities recorded by stations are found to be consistent with modulation spectra of the form (1−K/P and exp(−K/P) during the periods of increasing and decreasing cosmic-ray intensity. The question of the apparent phase lag of the cosmic-ray intensity behind the solar activity has also been examined. It is shown that the cosmic-ray intensity is well correlated with the emission of the coronal line, λ5303, from the vicinity of the solar equator.
The change in the energy spectrum of galactic cosmic rays over the 11-year solar activity cycle
Authors: Stozhkov Yu. , Charakhchyan T. N.
Published: April 2011

The energy spectrum of galactic cosmic rays has been investigated for various periods of the solar activity. In the framework of commonly used ideas about the mechanism of the 11-year variation according to Parker the dependence of the cosmic-ray diffusion coefficient, D, on the particle rigidity, P, was determined. For the form D ≈ vpα the parameter α is found to change during the cycle of the solar activity.[Formula: see text]
Twenty-two-year revolutions in the cosmic-ray diurnal variations
Authors: Wada M. , Kudo S.
Published: April 2011

It is shown, from the data obtained during three complete sunspot cycles, that the 22-year variation in the phase of the cosmic-ray diurnal wave is associated with the 11-year revolutions of the diurnal vectors. The revolutions alternate in sense every 11 years. In order to interpret these revolutions, two perpendicular cosmic-ray streamings in interplanetary space are assumed. As both streamings undergo 11-year variations in their velocities, an ellipse is traced out by the termini of the annual vectors; the sense of revolution depends on whether the phase difference between the two is positive or negative. If, on the other hand, their periods are 11 and 22 years and if their phases coincide, the locus is a horseshoelike trajectory, which is traced twice by a to-and-fro motion during 22 years. The observed data available at this stage cannot distinguish between these possibilities. As geomagnetic activity also shows different 11-year variations alternately, its relation to the 22-year revolution in the diurnal variations is discussed. The radial flow of the cosmic-ray particles as well as the rigid rotation of the cosmic-ray gas with the sun suggested by Parker may correspond to the two streamings.
Modulation of low-rigidity cosmic rays and the power spectrum of the interplanetary magnetic field in 1962 and 1965
Authors: Jokipii J. R.
Published: April 2011

The observed change in cosmic-ray modulation from 1963–64 to 1965 may be associated with a corresponding change in the magnetic-field power spectra between 1962 and 1965, as obtained from Mariner 2 and Mariner 4 magnetometer data, respectively. It is further suggested that the diffusion mean-free-path λ may approach a constant value approximately equal to the correlation length of the magnetic field for very-low-rigidity particles.
Matrix method of investigation of the cosmic-ray distribution
Authors: Krymsky G. F. , Krivoshapkin P. A. , Kuzmin A. I.
Published: April 2011

The cosmic-ray directional distribution is expanded in a series of spherical harmonic functions. Matrices are introduced which modify the expansion coefficients for rotation of the coordinate system. The relationship between the expansion coefficients and diurnal variations is established. The mechanism generating the second spherical harmonic due to cosmic-ray screening by regular magnetic fields is discussed, and the parameters of the corresponding diurnal and semidiurnal variations depending on the spatial orientation of the interplanetary magnetic field are calculated.
Macro- and micro-structure of the interplanetary magnetic field
Authors: Burlaga Leonard F. , Ness Norman F.
Published: April 2011

A radial gradient of the interplanetary magnetic field between 0.81 and 1.0 AU has been observed in agreement with Parker's model. The average magnitude of the magnetic field component perpendicular to the ecliptic plane was zero during 1966.Discontinuities in the direction of the magnetic field were observed when viewing on a scale of one hour; directional distributions are presented which describe the topology of these discontinuities. It was found that sometimes a large, discontinuous change in the field direction was accompanied by a dip in the field intensity; the measured minimum magnetic field intensity agrees with the value calculated from the hypothesis that the dip was the result of magnetic field annihilation. At least two of these "D-sheets" appear to be transitional regions associated with tangential discontinuities.
A study of the modulation regions causing 27-day cosmic-ray variations
Authors: Alania M. V. , Shatashvili L. Kh. , Dorman L. I.
Published: April 2011

This is an attempt to determine the effective size of the interplanetary medium responsible for the 27-day variation in the cosmic-ray intensity. Neutron data from Mt. Norikura and Climax have been correlated with sunspot data for 80 solar revolutions beginning July 1957. The size of the modulating region was estimated from the lag between the sunspot number and the cosmic-ray variations, assuming the solar wind speed to be 400 km s−1, and it was found to be comparable with, or less than, the effective size of the modulating region causing the 11-year variation.
Multiplicity measurements on the IGY and NM64 neutron monitors
Authors: Bachelet F. , Dyring E. , Iucci N.
Published: April 2011

Preliminary results are given of the analysis of the continuous recordings of the detected multiplicity distribution obtained at the Uppsala IGY monitor and at the Rome supermonitor in the first months of 1967. The relative frequencies and the attenuation coefficients of the individual multiplicities as measured at both monitors are compared. The time changes of the multiplicity distribution on the occasion of substantial primary spectral variations are studied.
On the correlation between the primary cosmic radiation and the directional muon flux in the lower atmosphere
Authors: Åström Kjell
Published: April 2011

The directional muon spectra are reproduced using the diffusion equations, independent measurements of the primary spectrum, the multiplicity in pion production, and the three-dimensional spectrum of pion production in nucleon – light nuclei collisions at accelerator energies extended to high primary energies by a modified CKP model. With an attenuation mean free path L ≈ 140 g cm−2 the calculated muon spectra in the momentum interval 0.2–50 GeV/c at sea level correspond to observations to within ~±10% at 0°, ~±15% at 30°, and ~±20% at 60° to the zenith direction. At the level 700 g cm−2 in the zenith direction the shape of the calculated spectrum falls within the observational error limits. At 300 g cm−2 the intensity of muons falls ~30% below that recorded for the hard component.The atmospheric "multiplicity" (Dorman 1957) for the muon component is evaluated and stored as a five-dimensional matrix on magnetic tape. Some applications of this analysis are proposed.
Monte Carlo calculation of the nucleonic cascade in the atmosphere
Authors: Debrunner H. , Brunberg E. Å.
Published: April 2011

A Monte Carlo calculation of the nucleonic cascade in the atmosphere has been carried out. Preliminary results are presented and compared with measurements of the secondary proton spectrum at sea level.
A five degree by fifteen degree world grid of trajectory-determined vertical cutoff rigidities
Authors: Shea M. A. , Smart D. F. , McCall John R.
Published: April 2011

Vertical cutoff rigidities have been calculated for a world grid 5 degrees in latitude and 15 degrees in longitude using the Finch and Leaton sixth-degree simulation of the quiescent geomagnetic field. These calculations utilized the trajectory-tracing procedure at intervals of 0.01 BV throughout the penumbral region to determine an "effective" vertical cutoff rigidity defined by Shea et al. (1965). When experimental cosmic-ray intensity data are plotted using threshold rigidities derived from this grid, greater coherence of these data is found than is obtained using previously published threshold values. However, small deviations from an intuitively pleasing smooth curve indicate we may have reached a limitation in the usefulness of vertical cutoff rigidities, and perhaps second-order effects should be included when using cutoff rigidity as a parameter in the analysis of very precise cosmic-radiation intensity data.
Servo systems for Cerenkov light receivers
Authors: Fruin J. H. , Jelley J. V.
Published: April 2011

The paper describes a variety of servo systems which have been developed for use with Cerenkov light receivers. Particular attention is devoted to the problem encountered in the high-energy γ-ray astronomy application, namely that the total background light within the field of view should be maintained constant during individual drift-scans or on–off comparison runs.Both filament lamps and midget fluorescent indicating lamps have been used as the active elements in the servo loops, and the systems have been operated either (a) from the phototube current or (b) from the counting rate at a selected pulse-height discrimination level. The characteristics of the various systems are discussed, in relation to the control factor, dynamic range, and stability. One of the systems developed was fast enough to respond to stellar atmospheric scintillations in the frequency range d-c. to 1 kHz.A servo system of a different type is also described, in which the sensitivity rather than the background light can be stabilized; in this way it was found possible to accommodate large variations of background light over long periods.
Large-area proportional detectors
Authors: Ashton F. , Coats R. B. , Kelly G. N. , Simpson D. A. , Smith N. I. , Takahashi T.
Published: April 2011

The relative merits of using scintillation counters or proportional counters in a very large area (~100 m2) telescope to search for a flux of relativistic quarks are considered. It is shown that proportional counters are more satisfactory for large-area detectors and that counters 10 m long and 14.5 cm in internal diameter filled with 90% argon, 10% methane gas should give a signal of ~2 mV at the input to an emitter follower on the passage of a relativistic e/3 quark along an average chord length.
A proposed apparatus for the measurement of the cosmic-ray muon momentum spectrum and charge ratio, and the investigation of muon interactions
Authors: Bull R. M. , Nash W. F. , Milne Wendy J. , Woodham R. E. , Yeivin Y. , Frohlich A.
Published: April 2011

The construction of a cosmic-ray spark-chamber spectrometer for use in the study of the charge ratio and interactions of muons at energies up to 3 000 GeV is proposed. The apparatus will consist of a stack of interleaved spark chambers and magnetized iron plates, placed at a depth of 250 m.w.e. underground in order to remove the low-energy component of the cosmic-ray muon flux. This report gives an appraisal of the design of the apparatus and summarizes its expected performance.
A measurement of transition effects in electromagnetic cascades
Authors: Fetisov I. N.
Published: April 2011

The results of the measurements of the transition effects are shown for an electromagnetic cascade which has been developed in lead and has passed (before measurement) through the copper wall of an ionization chamber. The measurements were carried out in the electron beam of an accelerator in the energy range 100–550 MeV. The integral value of the transition effect was [Formula: see text] for a 2.5-mm-thick wall and it increased slightly with increase in the wall thickness. The values of the transition effects for the various age parameters of a cascade are shown.
Plastic track detectors for identifying cosmic rays
Authors: Price P. B. , Peterson D. D. , Fleischer R. L. , O'Ceallaigh C. , O'Sullivan D. , Thompson A.
Published: April 2011

Experiments have been carried out on the use of dielectric track detectors for the identification of particles of different masses. Five different plastics of widely differing sensitivities have been used. Experiments were carried out using the Yale Heavy Ion Accelerator with various ions from 0 to 10.3 MeV/N. The results indicate that it should be possible to use this technique to measure relative abundances over a wide range of mass values, where the particles are of such an energy that they are stopped in the pack of plastic sheets.
A cosmic-ray spectrograph using the spark chamber technique
Authors: Allkofer O. C. , Dau W. D. , Kraft E.
Published: April 2011

In this paper the characteristics of a cosmic-ray spectrograph which uses a solid iron magnet as the deflecting element are described. The particle tracks are registered by six spark chambers having double gaps. These spark chambers are triggered by four layers of G-M counters which are used also for a preselection of the momentum up to 50 GeV/c. The deflection power of the magnet, ∫B"∙dl, is 3.2 × 106 gauss-cm; the momentum range is 7–5 000 GeV/c; the collection power amounts to 7.1 cm2 sr, and the measured rate is 18/h.
Investigations on a sonic spark chamber
Authors: Priesmeyer H. G. , Roose U. J. , Trümper J.
Published: April 2011

A 1 × 1 m2 sonic small-gap spark chamber using long piezoelectric microphones has been tested. The propagation of the cylindrical shock wave is characterized by an excess velocity[Formula: see text]For distances r from spark to microphone ranging from 0.1 to 1 m a Δv = const. × r−0.9±0.1 law is found. The error of spark location increases with r and is 0.35 and 0.55 mm at r = 0.1 and 1 m respectively. The influence of spacers on the propagation of the shock waves is discussed.
Rayleigh–Brillouin Scattering in Compressed H2, D2, and HD. II
Authors: Hara E. H. , May A. D.
Published: April 2011

The observations presented by Hara et al. for the Brillouin spectrum of H2, D2, and HD are compared with the thermo-hydrodynamic theory of Bhatia and Tong. It is noted that although this theory is qualitatively correct it fails to describe accurately the spectrum at low to medium densities. It is suggested that the introduction of a relaxing thermal conduction might account for the discrepancy observed.
The Effect of Wind Shear Gradients on Underdense Radio Meteor Decay Times
Authors: Jones J. , Read B. A.
Published: April 2011

It is shown that wind shear gradients in the meteor region can cause a scatter in the decay time of underdense radio meteor echoes. This model agrees well with the experimental observations of forward scatter radio meteors, but in the case of backscatter echoes the wind shear gradient component of the dispersion in the decay times is much smaller than that observed. It is shown that for backscatter echoes the dispersion in decay times is probably almost completely due to cosmic noise.
Search for Broad Resonances in 3He
Authors: Bunker S. N. , Jain Mahavir , Miller C. A. , Nelson J. M. , Tivin P. J. , van Oers W. T. H.
Published: April 2011

Recently experimental evidence has been presented for the existence of broad T = 1/2 resonances in the three-nucleon system. As a continuation of earlier studies the 6Li(p,α) reactions were investigated using 45.0 MeV incident protons. 3He and alpha-particle spectra were measured at extreme forward angles using a ΔE–E–VETO detector telescope in conjunction with an analog particle identifier. Excitation energies up to 30 MeV in 3He could be examined. The spectra do not show any structure that can be related to the resonances observed previously. However, the spectra exhibit evidence for quasi-free scattering of protons from the α cluster in 6Li. In a complementary study the 3He(p,2p) reactions were investigated at an incident energy of 45.0 MeV. Data were taken with coplanar, symmetric geometry at 10 pairs of angles between 25° and 60° and also with coplanar, asymmetric geometry at the following pairs of angles: θ1 = 40°; θ2 = 30°, 37.4°, 40°, 45°, 50°, 55°, 60°, and 70°. Pronounced kinematic bands due to the 3He(p,2p)d and 3He(p,2p)d* reactions were observed. A comparison of the continua of coincident proton–proton events with the predictions of four-body phase-space calculations shows good agreement. The four-body continua do not show any anomalies which can be interpreted as due to broad resonances in 3He.
Mesures de Hall AC dans les Oxydes Métalliques
Authors: Perluzzo G. , Yahia J.
Published: April 2011

An apparatus has been developed for AC measurements of the Hall constant in high impedance and low mobility materials. For such systems, our method gives better results than the DC method almost universally used. Reasons for this are given in the paper.The apparatus has been used for a detailed study of Hall mobility, at room temperature, of four metal oxide crystals with widely different charge carrier densities. Contrary to expectation, the mobility is found to decrease with increasing density.A polaron mass (in the low charge density limit) is calculated for titanium dioxide at room temperature, using the measured mobility.
Thermal and Electrical Conductivities of Sodium from 40 to 360 K
Authors: Cook J. G. , Meer M. P. Van der , Laubitz M. J.
Published: April 2011

We present data on the electrical and thermal resistivities and the thermopower of three pure Na specimens from 40 to 360 K. The measurements were made using a guarded longitudinal heat flow apparatus that had previously been calibrated with Au and Al. The specimens were placed in a vacuum environment using no solid inert liner.The electrical resistivity data indicate ΘR = 194 K. The thermal conductivity data show a 4% minimum near 70 K and an ice point value of 1.420 W/cm K. The reduced Lorenz function L/L0 agrees with published data at low temperatures but above 300 K levels off at approximately 0.91. On the basis of published data for liquid Na, L/L0 does not change by more than 3% at the melting point.The minimum in the thermal conductivity and a part of the high temperature deviations of L from L0 are tentatively ascribed to inelastic electron–phonon collisions having a characteristic temperature near that of longitudinal phonons. The possibility that electron–electron collisions further depress L at high temperatures is critically examined.
Properties and Interactions of Lanthanides: Interactions with External Fields
Authors: Saxena K. M. S. , Fraga S.
Published: April 2011

The values of the diamagnetic susceptibilities and nuclear magnetic shielding constants, calculated from numerical Hartree–Fock functions, are reported for the neutral atoms and the first three positive ions of the lanthanides.
Measurement of the Total Cross Sections of Positrons on Helium Atoms in the Energy Range 15 to 23 eV
Authors: Jaduszliwer B. , Keever Wm. C. , Paul D. A. L.
Published: April 2011

Positron cross sections on helium have been measured by transmission using a weak beam of energy-analyzed positrons in the range 15 eV to 23 eV. The positrons are transmitted in a magnetic field parallel to the axis of the scattering chamber. Comparisons with theory have been made using several sets of phase shifts, and good agreement is found if the latest p- and d-wave phase shifts of Drachman are used. The experiments fail to show any sharp reduction in the transmission at the positronium threshold, from which we deduce an upper limit to the positronium formation cross section of [Formula: see text]. The agreement between our results and those of Costello et al. in the neighborhood of 17 eV is very good.
On the equation describing the transient flow of a compressible liquid through deformable porous media
Authors: BačlićF B. S. , Sekulić D. P.
Published: April 2011

The effect of the linearized treatment of the equation describing the transient flow of a compressible liquid through elastic porous media is studied analytically in this paper. It is shown that if there is a need for a simplified description based on the linearization of the original nonlinear partial differential equation, then it has to be done in an optimal sense. However, even then the mathematical model may degenerate for certain boundary conditions and some values of parameters defining the dependence of fluid and media properties on pressure. This fact is illustrated by the help of a simple example of transient filtration in a semi-infinite Hookeian medium. The reliability and adequateness of the a priori linearized equation is discussed.
Magnetic properties of one-dimensional dilute Heisenberg system
Authors: Matsubara Fumitaka , Sampei Masaru , Katsura Shigetoshi
Published: April 2011

The magnetic properties of the one-dimensional dilute Heisenberg system of spin [Formula: see text] are studied in terms of power series of concentration of magnetic atoms p. Any extensive quantity A is given by [Formula: see text]for ferromagnetic and antiferromagnetic couplings. The An are obtained from the partition function of the finite open chain up to n = 11, and from extrapolation for [Formula: see text]. The former is calculated by using irreducible representation of permutation groups. The specific heats and the magnetizations of both the ferromagnetic system and the antiferromagnetic system are obtained and the p-dependences of those quantities are discussed.
Levels in the 4d86s and 4d85d configurations of the fifth spectrum of indium: In V
Authors: Srivastava R. P. , Joshi Y. N. , vanKleef Th. A. M.
Published: April 2011

The spectrum of indium has been photographed in the region 600–1500 Å on a 10.7 m normal incidence spectrograph. The source used was a sliding spark. Forty-three levels belonging to the 4d85d and two levels of the 4d86s configuration have been established in In V. Parametric level fitting calculations confirm the analysis. Two hundred and eighty-nine additional lines were classified in this spectrum.
Some aspects of thermal and elastic properties of yttrium
Authors: Rao R. Ramji , Rajput A.
Published: April 2011

A systematic calculation of the lattice heat capacity, third-order elastic constants and the temperature variation of the effective Grüneisen functions of the hexagonal close-packed metal yttrium is carried out using the approach of Keating. The normalized frequency distribution function employed for specific heat calculations is obtained using 50 880 frequencies. Good agreement is found between the calculated and experimental Cv1 values. The l0 third-order elastic constants are evaluated using two anharmonic parameters and these, in turn, are utilized to calculate the low-temperature limit [Formula: see text] of thermal expansion, the Anderson–Güneisen (A–G) parameter δ, and the second Grüneisen constant q of yttrium. The temperature dependence of the volume Grüneisen function and its high-temperature limit [Formula: see text] are determined. The theoretical values of [Formula: see text] and [Formula: see text] are in excellent agreement with those estimated from the experimental thermal expansion data of Meyerhoff and Smith obtained for this metal. The calculated value of the A–G parameter δ is used in Anderson's equation to determine the temperature variation of the bulk modulus of yttrium and it is found that the change in Bs from 4 to 400 K calculated in this manner shows good agreement with that estimated from the experimental results of Smith and Gjevre. The variation of the lattice parameters of yttrium with hydrostatic pressure is also investigated using its third-order elastic constants and Thurston's extrapolation formulae.
Elastic constants and anisotropic pair correlations in solid hydrogen and deuterium
Authors: Luryi S. , Kranendonk J. Van
Published: April 2011

The anisotropic displacement–displacement correlation function for the two types of pairs of nearest neighbours in solid hep hydrogen and deuterium is studied. Two mechanisms contributing to the deviation of the pair distribution function from axial symmetry around the pair axis are identified. The one is due to the anisotropy of the phonon dispersion relations and is treated in a generalized Debye model parameterized in terms of the elastic constants. The elasticity tensor is decomposed into rotationally irreducible parts, and certain new relations between the elastic constants of hep crystals with central forces are derived. The other mechanism arises from the immediate, anisotropic environment of a pair and is treated using a generalized Einstein model. The relevance of these results for the interpretation of the microwave spectrum of pairs of orthohydrogen molecules in parahydrogen is also discussed.
Les modes non de révolution dans les guides d'ondes corrugués
Authors: Buge J. P. , Fabre G. , Wick A. , Zepp G.
Published: April 2011

The propagation of nonrevolution modes in corrugated waveguide has been studied. An accurate method for the determination of dispersion equation of the waveguide (nonrevolution modes) is described. The variation of wavelength and wave attenuation in terms of geometric parameters of the guide is then determined. It is shown that the experimental results are in satisfactory agreement with the theory.
Interactions between cylindrical bodies and supersonic flowing plasmas: measurements in the front and rear stagnation regions for a cylinder in cross-flow
Authors: Ogram G. L. , Chang Jen-Shih , Hobson R. M.
Published: April 2011

The forward and rearward facing regions near the surface of a cylindrical conducting body mounted transversely to a supersonic flowing continuum plasma were investigated by local current measurement. Experimental results show that the electron current is affected by the asymmetrical temperature profile created around the cylinder by the flow, and that the ion current is also significantly enhanced by the flow.
Etude numérique des modes et fréquences propres d'une cavité à l'aide de la fonction de Green
Authors: Imbeau Jacques A. , Darling Byron T.
Published: April 2011

We apply the methods developed in our preceding paper (J. A. Imbeau and B. T. Darling. Can. J. Phys. 57, 190(1979)) for calculating the Green's function of a cavity to obtain the normal modes and normal frequencies of the cavity. As the frequency of the driving point source approaches that of a normal frequency the response (Green's function) of the cavity becomes infinite, and the form of the Green's function is dominated by the normal mode. There is also a 180° reversal of phase in passing through a resonance. In this way, we are able to calculate the normal frequencies of prolate spheroidal cavities to the full precision employed in the calculations (16 significant digits for double precision of the IBM-370). The Green's functions and the normal functions are also obtainable to a high degree of precision, except in the immediate vicinity of the surface of the cavity where they suffer a well-known discontinuity.
Response of the mid-latitude ionosphere to solar magnetic sector crossing
Authors: Lyon G. F. , Bhatnagar V. P.
Published: April 2011

Using sector boundary passages past the earth as key days, a superimposed epoch analysis has been carried out of Total Electron Content, foF2 and hpF2. It is found that there is an enhancement of Total Electron Content on the key day for toward-to-away (−, +) sector boundary crossings only, and that this effect is greater in winter (~ 15%) than in summer (~ 10%). The correlation with (−, +) solar magnetic sector crossings (SMSC) seems to derive from the Svalgaard–Mansurov effect but the reason for seasonal effects remains in doubt.
Precise atomic masses for titanium
Authors: Kozier K. S. , Sharma K. S. , Barber R. C. , Barnard J. W. , Ellis R. J. , Derenchuk V. P. , Duckworth H. E.
Published: April 2011

The 1.00 m radius high resolution mass spectrometer at the University of Manitoba ('Manitoba II') has been used to determine the atomic masses of 47Ti and 48Ti. These data are somewhat superior in precision to existing values and improve the reliability of atomic mass data in that region of the mass table.
Single-proton states in 155Eu
Authors: Burke D. G. , Løvhøiden G. , Straume O. , Flynn E. R. , Sunier J. W.
Published: April 2011

The [Formula: see text] reaction was studied using 17 MeV polarized tritons from the tandem Van de Graaff accelerator at the Los Alamos Scientific Laboratory. The alpha particles were analyzed using a Q3D magnetic spectrometer and detected with a helical-cathode position-sensitive counter. The overall resolution was ~ 18 keV FWHM. Some additional exposures, performed using unpolarized tritons on a thinner target, had a resolution of ~ 12 keV FWHM and were helpful in the interpretation of a number of multiplets. Measurements of the 154Sm(α,t)155Eu reaction were made using 25 MeV alpha beams from the McMaster University tandem accelerator. The triton spectra were analyzed with a magnetic spectrograph using photographic emulsions for detectors, yielding a resolution of ~ 10 keV FWHM. By comparing the measured angular distributions of [Formula: see text] cross sections and analyzing powers with DWBA predictions it was possible to assign spins and parities to many levels. The present results confirm earlier assignments of rotational bands based on the low-lying 5/2+[413], 5/2−[532], and 3/2+[411] orbitals. In addition, states at higher excitation have now been assigned to the 1/2+[411], 1/2+[420], and 7/2+[404] orbitals, and a 3/2+[422] band is tentatively proposed. The spectroscopic strengths can be explained reasonably well by the Nilsson model when pairing and Coriolis mixing effects are included.
Renormalized interactions in solid hydrogen and analysis of the ortho-pair level structure
Authors: Luryi S. , Kranendonk J. Van
Published: April 2011

The orientational level structure of o-H2 pairs in a solid p-H2 matrix is studied theoretically, with particular attention paid to the phonon renormalization of the anisotropic interactions. For the two- and three-body multipolar and induction forces, this renormalization is performed analytically and the results are expressed in terms of a small number of lattice dynamical parameters describing the shape of the anisotropic distribution function, g(u12), of the relative zero-point displacement of a pair of molecules. A microscopic calculation of these parameters has revealed that the difficulties remaining in the theoretical analysis carried out by Harris, Berlinsky, and Hardy of the microwave spectra observed by Hardy, Berlinsky, and Harris stem from an incorrect parametrization of the deviations of g(u12) from cylindrical symmetry. Using our renormalization results, as well as a more convenient symmetry classification of the effective interactions in the solid, we arrive at an analysis of the microwave spectra which appears to be free of difficulties. From this analysis we obtain the following values of the effective anisotropic interaction constants in solid H2 at normal pressure: the quadrupolar coupling constant [Formula: see text] and the van der Waals coupling constants [Formula: see text], [Formula: see text], and [Formula: see text].
Temperature dependence of the elastic constants of holmium between 80 and 140 K
Authors: Simpson A. M. , Jericho M. H. , Roger W. A.
Published: April 2011

High resolution elastic constant measurements on a holmium single crystal were made between 80 and 140 K. The results near TN suggest that in holmium the c-axis stress dependence of TN is opposite in sign and about three to four times larger than the basal plane stress dependence. The measurements further show that the 95 K anomaly is present only in C44 and that the magnitude of the anomaly diminishes with sample annealing thus supporting a domain origin for the effect.
Effects of higher order contribution and of ion temperature on ion-acoustic solitary waves
Authors: Lai C. S.
Published: April 2011

The combined effects of ion temperature and higher order corrections on ion-acoustic solitary waves are studied on the basis of the reductive perturbation method. The basic set of fluid equations for warm-ion fluid are reduced to the renormalized warm-ion Korteweg – de Vries equation for the first-order perturbed potential and a renormalized linear inhomogeneous equation for the second-order perturbed potential. Stationary solutions of the coupled equations are obtained, and the velocity and width of solitons calculated are in agreement with the experimental observation.
Method of Gaussian quadrature in the calculation of optical absorption and magnetic circular dichroism spectra of s2 ions in alkali halide crystals: application to KBr:In+
Authors: Kamishina Y. , Sivasankar V. S. , Jacobs P. W. M.
Published: April 2011

The problem of calculating the lineshape function for optical absorption and magnetic circular dichroism due to ionic impurities with the ns2 outer electron configuration, incorporated substitutionally in alkali halide crystals, has been reformulated. The complete energy matrix has been diagonalized directly. Integration over the interaction mode coordinates of Eg and T2g symmetry has been carried out numerically using Gaussian quadrature formulae; the interaction with the A1g mode has been taken into account by the usual convolution procedure. The method has been applied to KBr:In+. The calculated lineshape functions for optical absorption at temperatures ranging from 4 to 300 K and, for MCD at 5 K, are in good agreement with the experimentally determined lineshapes. Moreover, the theory accounts very well for the observed variation of the effective g tensor for the A band with temperature. The calculated values for the moments of the absorption and MCD lineshape functions are in reasonably satisfactory agreement with those deduced from the observed spectra.
Graphical solutions of renormalization group equations
Authors: Lam C. S. , Marleau G. C.
Published: April 2011

We show that when the β and γ functions in the Callan–Symanzik equation are calculated to a finite order in perturbation theory, the solution to the equation may be represented by an infinite series of Feynman diagrams obtained by repeated insertions of the lower order diagrams from which the β and γ functions are calculated. We demonstrate this assertion in two ways, by explicitly calculating these graphs in the leading logarithm approximation, and by proving that this set of diagrams satisfies exactly the Callan–Symanzik equation.