AN APPARENT ANOMALY OF THE BAROMETRIC COEFFICIENT FOR THE NUCLEONIC COMPONENT OF COSMIC-RAY INTENSITY

1964 ◽  
Vol 42 (10) ◽  
pp. 1847-1856
Author(s):  
S. M. Lapointe
Keyword(s):  
Statistical Analysis ◽  
Pressure Coefficient ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Attenuation Length ◽  
Cosmic Ray Intensity ◽  
Simple Theoretical Model ◽  
Standard Neutron ◽  
Nucleonic Component ◽  
Barometric Coefficient

A statistical analysis, based on three and one-half years of observational data, previously published by Lapointe and Rose (1962), produced a larger barometric coefficient for the nucleonic intensity in the standard neutron monitor at Sulphur Mountain (altitude 2283 meters) than at Ottawa (same geomagnetic latitude, sea level station).To explain this apparent anomaly, a simple theoretical model is presented which reproduces the results of this statistical analysis. The model treats the nucleonic component as consisting of two distinct cascades of nucleons, one "hard", characterized by a greater attenuation length and smaller pressure coefficient, and one "soft", characterized by a shorter attenuation length and larger pressure coefficient. The validity of the model is discussed.

ON DIURNAL VARIATION IN COSMIC-RAY INTENSITY AT OTTAWA

1955 ◽  
Vol 33 (10) ◽  
pp. 577-587
Author(s):  
S. D. Chatterjee ◽  
J. N. Bloom
Keyword(s):  
High Pressure ◽  
Statistical Analysis ◽  
Diurnal Variation ◽  
Ionization Chamber ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Rigorous Statistical Analysis ◽  
Local Mean ◽  
Mean Time ◽  
Barometric Coefficient

Cosmic-ray data from a high pressure integrating ionization chamber, obtained at Ottawa, for 129 complete days during September 1950 to July 1951 are subjected to rigorous statistical analysis. The barometric coefficient is −0.19% per mm. of Hg for the period covered by this analysis. The results also indicate a physically significant 24-hr. wave in cosmic-ray intensity, with an amplitude of 0.12% of the total intensity, having its maximum at about 10.40 a.m. local mean time. The existence of the semidiurnal wave, however, is not physically significant.

A STATISTICAL ANALYSIS OF THE BAROMETER COEFFICIENTS FOR COSMIC-RAY INTENSITIES

1962 ◽  
Vol 40 (6) ◽  
pp. 687-697 ◽  
Author(s):  
S. M. Lapointe ◽  
D. C. Rose
Keyword(s):  
Statistical Analysis ◽  
Sea Level ◽  
Neutron Monitor ◽  
Seasonal Variations ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Seasonal Fluctuations ◽  
Latitude Effect ◽  
Standard Neutron ◽  
The One

The data from all four Canadian cosmic-ray stations, Ottawa, Resolute, Churchill, and Sulphur Mountain, have been analyzed statistically with the help of an I.B.M. 650 computer over a period of three and a half years extending from the beginning of the I.G.Y. in July 1957 to the end of 1960. The barometer coefficients for triple and double coincidences in the international cubical telescope and for the nucleon intensity in the standard neutron monitor have been derived. A single correlation between intensity and pressure was used; two different ways of effecting this correlation were tried over a 6-month period. The results were compared and the best method was applied to the remaining three years. Monthly values were calculated, as were yearly values and also values for the 3-year period. The results reveal no significant seasonal variations in the barometer coefficients and no significant year-to-year variation. However, the seasonal fluctuations of the nucleon coefficient unsuspectedly follow those of the meson. A small latitude effect seems to be present. The nucleon coefficient at Sulphur Mountain, a high altitude station, is larger than the one at Ottawa (same geomagnetic latitude, sea level station).

CHANGES IN THE DIURNAL HOUR OF MAXIMUM OF THE COSMIC-RAY INTENSITY

1961 ◽  
Vol 39 (10) ◽  
pp. 1477-1485
Author(s):  
J. Katzman
Keyword(s):  
Solar System ◽  
Interplanetary Space ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Latitude Belt

The diurnal hour of maximum of the meson component changed progressively at Ottawa, Canada, from 10 hr 44 min to 14 hr 40 min during the period January 1955 to December 1960 while the nucleon component changed from 12 hr 12 min to 15 hr 16 min for the same period. This evidence favors the 22-year cycle in the diurnal hour of maximum that was first suggested by Thambyahpillai and Elliot, for stations within a geomagnetic latitude belt between 58.1° N. and 48.1° S. The diurnal hour of maximum at Churchill changed from 14 hr 40 min to 15 hr 24 min during the period April 1957 to December 1960 for the meson component and from 15 hr 12 min to 15 hr 52 min for the nucleon component. Although the change was for a later hour the indication of a 22-year cycle at Churchill is not impressive. At Resolute the diurnal hour of maximum is dominated by the varying magnetic masses in interplanetary space. It is shown that the anisotropy varies both in magnitude and direction depending on the conditions that exist in the solar system.

THE VARIATION OF SEA LEVEL COSMIC RAY INTENSITY BETWEEN 1954 AND 1957

1958 ◽  
Vol 36 (7) ◽  
pp. 824-839 ◽  
Author(s):  
A. G. Fenton ◽  
D. C. Rose ◽  
K. B. Fenton
Keyword(s):  
Solar Activity ◽  
Sea Level ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
High Solar Activity ◽  
General Level ◽  
Intensity Level ◽  
Cosmic Ray Intensity ◽  
Primary Cosmic Radiation ◽  
The One

Results from neutron monitors and meson telescopes at Ottawa (geomagnetic latitude 57° N.) and Resolute (geomagnetic latitude 83° N.) are presented for the years 1954–57, a period of increasing solar activity. The results indicate that the sea level meson intensity at these latitudes decreased by 5–6% between April 1954 and December 1957. During the same period the intensity of the nucleonic component at these stations decreased by over 22%. Investigation of the relative response of the two types of recorder to transient decreases during this period indicates that the long term change in the intensity level cannot be explained completely as an accumulation of shorter transient decreases, which become more frequent at times of high solar activity. It is concluded that the transient decreases are superimposed upon the longer term changes, each being produced by a separate modulation process but ultimately controlled by the general level of solar activity. Significant differences are found in the shape of transient decreases observed at the Canadian stations, both between different components at the one station and the same component at different stations. These may be interpreted as due to a varying energy dependence from one transient decrease to another, and to anisotropy in the primary cosmic radiation at these times.

Two anisotropies of the cosmic-ray particles producing the cosmic-ray diurnal variation

1968 ◽  
Vol 46 (10) ◽  
pp. S828-S830
Author(s):  
Masatoshi Kitamura
Keyword(s):  
Cosmic Rays ◽  
Diurnal Variation ◽  
Interplanetary Space ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Diurnal Variations ◽  
Low Energy ◽  
The Other ◽  
Energy Spectra ◽  
Cosmic Ray Intensity

The solar diurnal variations of both meson and nucleon components of cosmic rays at sea level at geomagnetic latitude 57.5° and geomagnetic longitude 0° are analyzed by the model in which two anisotropies of cosmic-ray particles (one of them, Δj1, from about 20 h L.T. and the other, Δj2, from about 8 h L.T. in interplanetary space) produce the solar diurnal variation of the cosmic-ray intensity on the earth.When the energy spectra of Δj1 and Δj2 are represented by [Formula: see text] and [Formula: see text], respectively, where j0(E) is the normal energy spectrum of the primary cosmic rays, it is shown that the evaluation for m1 = 1, 2, m2 = 0 and the cutoffs at 8 and 10 BeV on the low-energy side of spectra of both Δj1 and Δj2 agree well with the observational results at Deep River.

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