Primary cosmic radiation in 1958 and variations

• Main Author: Anderson, Hugh Riddell
• Format: Thesis
• Language: English
• Published: California Institute of Technology 1961
• Subjects: Physics; Greenland; Thule
• Online Access: https://dx.doi.org/10.7907/5czf-da12; https://resolver.caltech.edu/CaltechETD:etd-03282006-130610

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. During the summer and fall of 1958, 38 pairs of simultaneous measurements of cosmic ray ionization in the atmosphere were made with integrating ionization chambers carried to high altitudes by balloons, and accompanied by barometric sensors. One of each pair of measurements was made at a base station and the other at a roving station which released balloons at a set of different geomagnetic latitudes ranging from 87°N to 79°S. The base station data exhibit variations with time corresponding to changes in the primary flux. The effects of the time variations upon the roving station measurements are partially removed with the aid of the base station data leaving the ionization as a function of latitude only. The symmetry of the geomagnetic field in the northern and southern hemispheres is studied by means of the latter data. By assuming a charge spectrum, the differential rigidity spectrum of primary cosmic rays in 1958 is calculated from the ionization as a function of latitude by means of geomagnetic theory. The corresponding integral spectrum shows that [...](>0.6 Bv) = 0.107 particles/cm(2) sec sterad, [...](>16 Bv) 0.012 particles/cm(2) sec sterad. A primary rigidity spectrum is calculated from similar data taken by Neher, et al. in 1954. The ionization at Thule, Greenland, from 1951-1960 is presented. These data show the inverse correlation between cosmic ray intensity and sunspot number, and suggest that the intensity modulation lags the sunspot number by about 6 months.