The Latitude and Longitude Effects in Cosmic Rays Over the United States and Canada at 30,000 Feet

Abstract

In order to calculate the relative positron activities the experimentally determined 4 ratio (JW/fo+VCKV/Sei+J"^^ was used. This gives a value of fiu + /^ai +ss 0.Q0l4:l from our observed value iW#6i=0.00775.The longest period of cyclotron bombardment which has been used for production of Cu w has been 4 hours. On the basis of the ratio of activities after 2J hours of bombardment time one finds that after 4 hours of bombardment time the relative positron activities /3 6 4 + /0 6 i + would be 0.00157. No positron source has been studied for a period lasting more than three half-lives of Cu 61 following the removal of the nickel target from the cyclotron. Using the data above one finds that even after three half-lives the sample which was bombarded for four hours would have a positron activity ratio /3 6 4 + /06i + =0.00733. Quite a bit less than one percent of the activity can thus be attributed to Cu 64 .This study verifies the fact that only negligible quantities of the Cu 64 positron activity existed in the samples which have been studied to determine the shape of the positron spectrum of Cu w .This work has been supported by the joint program of the ONR and AEC.i C. S. Cook and L. M. Langer. Phys. Rev. 74, 227 (1948). 2 G. E. Owen and C. S. Cook, Phys. Rev. 76, 1536 (1949. 3 The Auger electrons were assumed for this experiment to represent a ratio of intensities for the K-capture processes in the two isotopes under consideration. In reality a small amount of the intensity of the Auger line for Cu 61 would be caused by the internal conversion electrons. However, their intensity is much less than the iC-capture intensity and could not cause a detectable change in the experimentally observed value. [See Boehm, Blaser, Marmier, and Preiswerk, Phys. Rev. 77, 295 (1950) and Owen, Cook, and Owen (article to be submitted to Phys. Rev.).] * Bradt, Gugelot, Huber, Medicus, Preiswerk, and Scherrer, Helv.T HE change with geomagnetic latitude of the ionizing particles at 310 g/cm" 2 atmospheric pressure (30,000 ft.) that could penetrate various thicknesses of absorber was measured by Biehl, Neher, and Roesch 1 over a range of latitude of 64° geomagnetic north to the geomagnetic equator along longitude 80°W. These flights show that most of the latitude effect is over at 50° as one proceeds north and this was independent of the absorber used or of whether the total radiation at that altitude was measured or only that near the vertical. On the other hand Swann, 5 r 90 1 h h NO LEAD ABSORBER

Albedo neutrons in space

“…Averaging over latitudes and both sets of detectors, a decrease in the charged particle count rate of ~17 per cent is obtained in going from station 0 to station 3. Data obtained by Biehl and Neher [1950] with an ionization chamber on the same flights as Simpson [1951] would indicate an expected effect of about 7 per cent. Figure 7 is the wide scatter of points, indicating the necessity of long-term averages for obtaining statistically meaningful results.…”