Calculated specific yield functions for neutron monitors

1968 ◽  
Vol 46 (10) ◽  
pp. S1048-S1051 ◽  
Author(s):  
K. M. Wainio ◽  
T. H. Colvin ◽  
K. A. More ◽  
O. L. Tiffany
Keyword(s):  
Empirical Data ◽  
Cosmic Ray ◽  
Yield Function ◽  
Specific Yield ◽  
Neutron Monitors ◽  
The Monte Carlo Method ◽  
Yield Functions ◽  
Secondary Nucleon ◽  
Nucleon Flux ◽  
Calculated Flux

Results of calculations to determine specific yield functions for IGY neutron monitors are reported for vertically incident cosmic-ray protons in the range of 1 < Pc < 6 GV. The Monte Carlo method is used to calculate secondary nucleon-flux intensities at atmospheric depths of 312, 680, and 1 000 g/cm2. Experimental data on neutron monitor response are employed to relate the calculated flux data to count rates, and hence to specific yields, at the corresponding depths. Comparison with empirical data for the specific yield function at sea level shows fair agreement for rigidities less than 3 GV, but calculated yields are considerably smaller than the empirical data at higher rigidities. Various possible explanations for the discrepancy are discussed. At this time, the most probable cause appears to be the assumption that vertically incident cosmic rays produce most of the counts registered by neutron monitors.

On the derivation of cosmic ray specific yield functions

1959 ◽  
Vol 4 (41) ◽  
pp. 654-664 ◽  
Author(s):  
W. R. Webber ◽  
J. J. Quenby
Keyword(s):  
Cosmic Ray ◽  
Specific Yield ◽  
Yield Functions

Influence of Anisotropic Yield Functions on Parameters of Yoshida-Uemori Model

2013 ◽  
Vol 554-557 ◽  
pp. 2440-2452 ◽  
Author(s):  
Hirotaka Kano ◽  
Jiro Hiramoto ◽  
Toru Inazumi ◽  
Takeshi Uemori ◽  
Fusahito Yoshida
Keyword(s):  
Effective Strain ◽  
Yield Function ◽  
Strain Response ◽  
Material Parameters ◽  
International Conference ◽  
Polynomial Type ◽  
Calculated Stress ◽  
Yield Functions ◽  
Order Polynomial ◽  
Von Mises

Yoshida-Uemori model (Y-U model) can be used with any types of yield functions. The calculated stress strain response will be, however, different depending on the chosen yield function if the yield function and the effective strain definition are inappropriate. Thus several modifications to Y-U model were proposed in the 10th International Conference on Technology of Plasticity. It was ascertained that in the modified Y-U model, the same set of material parameters can be used with von Mises, Hill’s 1948, and Hill’s 1990 yield function. In this study, Yld2000-2d and Yoshida’s 6th-order polynomial type 3D yield function were examined and it was clarified that the same set of Y-U parameters can be used with these yield functions.

Cosmic ray pion-nucleon flux ratio in the atmosphere

1975 ◽  
Vol 1 (8) ◽  
pp. L63-L65 ◽  
Author(s):  
D P Bhattacharyya ◽  
D Basu ◽  
R K Roychowdhury
Keyword(s):  
Flux Ratio ◽  
Cosmic Ray ◽  
Pion Nucleon ◽  
Nucleon Flux

SOME FEATURES OF THE RESPONSE OF NEUTRON MONITORS TO LOW-ENERGY PARTICLES INCIDENT ON THE TOP OF THE ATMOSPHERE

1962 ◽  
Vol 40 (7) ◽  
pp. 906-923 ◽  
Author(s):  
William Webber
Keyword(s):  
Solar Flare ◽  
Sea Level ◽  
Ring Current ◽  
Internal Field ◽  
Low Energy ◽  
Intensity Increase ◽  
Neutron Monitors ◽  
Solar Particle Events ◽  
Yield Functions ◽  
Geomagnetic Cutoff

By comparing the measured intensities and spectra of solar particles at the top of the atmosphere with measured neutron monitor intensity increases at sea level for several solar particle events, a set of yield functions has been derived for these neutron monitors in terms of low-rigidity (0.5–2 BV) particles incident on the top of the atmosphere. The monitors are found to be significantly more sensitive to these low-rigidity particles than has recently been believed. Various characteristics of the response of neutron monitors to solar flare particles are discussed. In particular a method is described by which the intensity increase vs. latitude curve for the neutron monitors during these events can be utilized to derive a measurement of the deviations in geomagnetic cutoff from those expected from the earth's internal field only. Applying this to the November 15, 1960, event suggests that a ring current of moment M = 0.6 ME and radius R = 7.7 RE was flowing at 1130 U.T. on this day.

Daily variation of cosmic rays during quiet and disturbed periods in 1965 and 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S819-S822
Author(s):  
Pekka J. Tanskanen
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Neutron Monitors ◽  
Monthly Basis ◽  
Cosmic Ray Intensity ◽  
Variable Amplitude ◽  
Ecliptic Latitude ◽  
Streaming Velocity ◽  
Corrected Data

Data from super neutron monitors at Deep River, Churchill, Resolute, and Alert have been used to study the daily variation of cosmic-ray intensity during 1965 and 1966. Intensities have been examined on a daily, weekly, and monthly basis as a function of the asymptotic direction of vertically incident 7.5-BeV particles. The data have been analyzed in an earth-centered solar-ecliptic coordinate system in which daily (due to the earth's rotation) and seasonal (due to the inclination of the earth's axis to the ecliptic plane) variations of the asymptotic directions are considered.During undisturbed periods the daily variation has been examined by applying a digital filter to the pressure-corrected data and also to the data after subtraction of a variable-amplitude Parker–Axford theoretical diurnal variation. Particular attention has been paid to the dependence of the observed daily variation on the solar-ecliptic latitude of the asymptotic direction.Seventy-three percent of the weeks considered in 1965 and 1966 give the phase of the first harmonic in a direction 85° ± 35 °E. Sixty percent of the weekly periods show a daily variation as a function of solar-ecliptic latitude which is in agreement with the Parker–Axford "streaming-velocity" theory. During Forbush decreases the diurnal phase shifts towards earlier hours and the amplitude increases to two to three times the predecrease level.

THE EFFECTIVE DIRECTIONAL SENSITIVITY OF COSMIC-RAY NEUTRON MONITORS

1961 ◽  
Vol 39 (5) ◽  
pp. 668-676 ◽  
Author(s):  
S. M. Lapointe ◽  
D. C. Rose
Keyword(s):  
Energy Spectrum ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
The Other ◽  
Directional Sensitivity ◽  
Master Curves ◽  
Neutron Monitors ◽  
Atmospheric Absorption ◽  
Method Of Calculation ◽  
Set Of Points

The direction of maximum sensitivity of a neutron monitor is calculated numerically for a set of points on the same geomagnetic meridian but extending in latitude from the equator to the pole. This leads to two master curves, one for the longitude, the other for the latitude of this direction. From these curves this direction is obtained in geographic co-ordinates for some 20 cosmic-ray stations. The method of calculation is described taking into account atmospheric absorption and the energy spectrum of the incident particles. The aperture of the sensitive cone, or source width, is also calculated. Finally the accuracy of the results is discussed and the application of the concept of effective direction is described.

Diurnal cosmic-ray variation with the inclusion of the geometrical effects and the asymptotic cones of approach

1968 ◽  
Vol 46 (10) ◽  
pp. S809-S811 ◽  
Author(s):  
L. I. Dorman ◽  
S. Fischer
Keyword(s):  
Spatial Distribution ◽  
High Latitude ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
The Sun ◽  
Neutron Monitors ◽  
Asymptotic Cones ◽  
Diurnal Anisotropy ◽  
Geometrical Effects

Employing the data from cosmic-ray neutron monitors at high latitude, the spatial distribution of the axis of the diurnal anisotropy is determined. The effects of the earth's revolution around the sun on the diurnal intensity variation is investigated. A new method for further investigation of the spatial distribution of the anisotropy and for the determination of its spectra in various directions has been proposed.

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