Re-interpretation of OSO-III scintillation counter measurements of hard solar X-ray spectra
Hard solar X-ray spectra measurements, reinterpreting OSO 3 scintillation counter response due to pulse pile-up
Hudson, H. S.↗
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Observations of interstellar scintillations of pulsar signals at 2388 MHz
Interstellar scintillation index and fading time of pulsar signals at 2388 MHz
Downs, G. S.↗
Laboratory model for radio-star scintillation and other diffraction phenomena
Laboratory model for radio star scintillation and other diffraction phenomena by thin weak random phase changing screen including earth atmosphere or solar wind
Morgan, M. G.↗
Power spectrum of scintillations of a two- component radio source
Cygnus A two component radio source scintillations power spectrum observation by dipole array
Chivers, H. J. A.↗
Seeing and scintillation
Astronomical telescopes image motion, distortion and scintillation, examining atmospheric refractive index and density/temperature variation effects
Young, A. T.↗
Development of a worldwide model for Flayer-produced scintillation
An empirical approach to modeling the electron-density irregularities in the F layer of the earth's ionosphere that are primarily responsible for scintillation of transatmospheric VHF-UHF signals has been devised and tested. The work was directed toward two major goals: first, development of a worldwide model for describing the rms fluctuation in signal strength to be expected on an arbitrary satellite-to-earth communication link under average ionospheric conditions; and, second, investigation of the feasibility of similar modeling for description of the complete first-order distribution of signal strength.
Fremouw, E. J.↗
Peripheral venous scintillation angiocardiography in determination of left ventricular volume in man.
Left ventricular end-diastolic volume was determined by cardiac visualization after peripheral venous injection of a gamma-emitting isotope in 10 patients with organic heart disease. The left ventricular end-diastolic volume measured by the isotope method consistently averaged 9% less than that determined by the X-ray method. The mean difference in left ventricular end-diastolic volume was 21 ml. Excellent correlation between the two methods was observed. It is pointed out that peripheral venous scintillation angiocardiography compares well with left ventriculography in the determination of left ventricular end-diastolic volume in man.
Sullivan, R. W.↗
The shape of the F-region irregularities which produce satellite scintillations Evidence for axial asymmetry.
Correlation analysis of three-station observations of satellite amplitude scintillations, recorded at London, Canada during the summer of 1968, have been interpreted to give information on the height, size and shape of the ionospheric irregularities. The irregularities had a mean height of 390 km, and when interpreted in terms of the usual axially-symmetric, field-aligned model, had a mean axial ratio of 6.5, and a mean dimension transverse to the magnetic field of 0.7 km. None of these parameters showed any systematic trend with geomagnetic latitude. The data for one of the passes analyzed were inconsistent with axial symmetry, and when examined in terms of a more general model, 3 of 9 passes showed evidence of irregularities which were elongated both along and transverse to the earth's magnetic field, the elongation transverse to the field tending to lie in a north-south direction.
Moorcroft, D. R.↗
Measurement of energies using a glass-scintillator ionization spectrometer.
A method is proposed for obtaining the energies of high-energy hadrons incident upon a glass-scintillator ionization spectrometer. The description of the apparatus and of its calibration with cosmic ray muons is followed by a demonstration of the processing of the data obtained.
Gillespie, C. R.↗
Observations of the solar plasma using radio scattering and scintillation methods
Observations of the solar plasma using the interplanetary scintillation technique have been made at radial distances of 0.03 to 1.2 AU. The solar wind is found to be independent of ecliptic latitude and radial distance, except close to the sun where acceleration is observed. Plasma density irregularities on a scale near the proton gyro radius, which modulate the mean density by about 1 percent, are present throughout the observed range of radial distance.
Hewish, A.↗
Wavelength dependence of the interplanetary scintillation index
Published observations of the interplanetary scintillation index m sub z are shown to vary with wavelength in a manner consistent with a smooth, power law spectrum of plasma fluctuations. This is in contrast to recent work arguing that the data require a spectrum with two separate regimes. It is concluded that published observations of m sub z are consistent with either type of density spectrum.
Hollweg, J. V.↗
Very High-Frequency (VHF) ionospheric scintillation fading measurements at Lima, Peru
During the spring equinox of 1970, scintillating signals at VHF (136.4 MHz) were observed at Lima, Peru. The transmission originated from ATS 3 and was observed through a pair of antennas spaced 1200 feet apart on an east-west baseline. The empirical data were digitized, reduced, and analyzed. The results include amplitude probability density and distribution functions, time autocorrelation functions, cross correlation functions for the spaced antennas, and appropriate spectral density functions. Results show estimates of the statistics of the ground diffraction pattern to gain insight into gross ionospheric irregularity size, and irregularity velocity in the antenna planes.
Blank, H. A.↗
Chemical abundances of cosmic rays greater than 4.5 GV measured with a large area proportional counter-scintillation counter stack
A 6500 sq cm-ster cosmic ray detector consisting of twelve gas counter trays sandwiched between two large area circular scintillation counters was flown from Palestine, Texas in November of 1972 to study the composition of primary particles 1.5 GeV/nucleon in the charge range 3 to 30. For each analyzed event, a recording was made of (1) the particle trajectory using four 20 wire proportional counter trays, (2) the energy loss in each of the solid counters, and (3) the dE/dx losses in each of the twelve gas counters. The large dynamic range of the detector is established by operating six of the gas counters in the ionization mode. A description of the instrument and some preliminary results are given.
Lheureux, J.↗
Threshold detection in an on-off binary communications channel with atmospheric scintillation
The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence was investigated assuming a poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength was analyzed and semi-emperical relationships to predict the optimum detection threshold derived. On the basis of this analysis a piecewise linear model for an adaptive threshold detection system is presented. Bit error probabilities for non-optimum threshold detection system were also investigated.
Webb, W. E.↗
Chemical abundances of cosmic rays greater than 4.5 GV measured with a large area proportional counter-scintillation counter stack
A 6500 sq cm-ster cosmic-ray detector consisting of 12 gas counter trays sandwiched between two large-area circular scintillation counters was flown from Palestine, Texas in November 1972 to study the composition of primary particles greater than 1.5 GeV/nucleon in the charge range from 3 to 30. For each analyzed event, the particle trajectory was recorded, using four 20-wire proportional counter trays. Also recorded were the energy loss in each of the solid counters and the dE/dx losses in each of the 12 gas counters. The large dynamic range of the detector is established by operating six of the gas counters in the ionization mode. A description of the instrument and some preliminary results are given.
Lheureux, J.↗
Certain problems in the development and design of scintillation and Cerenkov counters
The feasibility is examined of increasing the effectiveness of the scintillation and Cerenkov counters through improving light collection of the recorded radiation on the photoelectric cathode of the photomultiplier. An example of how to select a detector of the directional plexiglas Cerenkov counter is given. Also presented are experimentally obtained amplitude distributions during the recording of cosmic ray muons. The necessity to obtain agreement between the characteristic spectrum of the photocathode of the photomultiplier and the spectrum of the recorded radiation is stressed.
Chukin, V. S.↗
Plastic scintillation counters with an area of 2 sq m
Two designs of plastic scintillation counters with an area of 2 sq m scanned in each case by a single photomultiplier of the FEU-49 type are described. The radial dependence of their light collection at the place of the path of the detected particle does not exceed 10% while the half width of the differential distribution of the pulse amplitudes from nonfiltered cosmic radiation at sea level is 90 to 95%, and 65%, the plastic thickness being 5 cm and 10 cm, respectively. The temperature coefficient of the counter is 0.32% per 1 C.
Yegorov, T. A.↗
Threshold detection in an on-off binary communications channel with atmospheric scintillation
The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence was investigated assuming a poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength was analyzed and semi-empirical relationships to predict the optimum detection threshold derived. On the basis of this analysis a piecewise linear model for an adaptive threshold detection system is presented. The bit error probabilities for nonoptimum threshold detection systems were also investigated.
Webb, W. E.↗