Observations of the cosmic-ray equator in the Pacific Ocean area

It is the purpose of this Letter to summarize the results obtained in the course of a latitude survey of the intensity of the nucleonic component of cosmic radiation in the Pacific Ocean area. This experiment was undertaken with the aim of determining the location of the cosmic-ray equator in a longitude range that had not been investigated previously with a detector of this type. The interest in the position of the cosmic-ray equator (position of minimum cosmic-ray intensity) stems from the work of Simpson, Fenton, Katzmann, and Rose [1956] which first demonstrated that the cosmic-ray equator did not coincide with the position of the magneticdipole equator. Further studies of this problem [Katz, Meyer, and Simpson, 1958], involving an extensive series of airborne crossings of the cosmic-ray equator, have confirmed this result. The present experiment was directed toward making observations in a region not covered by these flights.