INVESTIGATIONS ON THE ISOTROPY OF HIGH ENERGY COSMIC RAYS

Journal Article · Fri Jun 01 04:00:00 EDT 1962 · Dissertation Abstr.

OSTI ID:4819650

Delvaille, J P

The directional distribution of cosmic rays was measured in the energy range lO/sup 13/ to lO /sup 19/ ev. Two methods were used, both employing the detection of extensive air showers (EAS) by an array of 15 plastic scintillation detectors covering an area of ~ 1 km/sup 2/. For EAS containing less than 10/sup 7/ panticles, the counting rates of simple multiple coincidences were Fourier analyzed (after suitably correcting for atmospheric effects) to obtain the variation in cosmic ray flux in sidereal right ascension. In the region above 10/ sup 7/ particles, the raethod of fast-timing and pulse height measurements gave the individual directions of the primary particles as well as the shower sizes. The results may be summarized as follows: (i.) In the interval 3 x 10/sup 13/ to 10/sup 16/ ev, the flux of cosmic rays is isotropic to 0.5%. Most of the experiments in this field (including the present one) indicate a positive excess of flux in the vicinity of the galactic center or inward spiral arm. However, some discussion is presented concerning the effects of uncompensated, seasonal atmospheric modulations on these measurements. In particular, not only is it possible that such modulations could account for the majority of the results but it is felt that solar diurnal phase modulation may ultimately set an upper limit to the accuracy with which time variation experiments may be performed. (ii.) There seeras to be a curious second harmonic (amplitude 17 plus or minus 5%; time of max 9 7/sup hr/ 21 7/sup hr/) in the range 10/sup 17/ to lO/sup 18/ ev. (iii.) Some anisotropy corresponding to an excess of flux in the galactic disc may be present for energies greater than lO/sup 18/ ev. (iv.) Nine events were observed with energies well in excess of one joule; they appear to be isotropic. In addition, experimental data on the fluctuations in the average radius of curvature of the shower from (2.85 plus or minus 0.04 km) are presented.

• Research Organization: Cornell Univ., Ithaca, N.Y.
• NSA Number: NSA-16-024665
• OSTI ID: 4819650
• Journal Information: Dissertation Abstr., Journal Name: Dissertation Abstr. Vol. Vol: 22
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANISOTROPY
ATMOSPHERE
COINCIDENCE METHODS
COSMIC RADIATION
DETECTION
ENERGY RANGE
EXTENSIVE AIR SHOWERS
LATTICES
MEASURED VALUES
METEOROLOGY
MODULATION
PHYSICS
POLYMERS
SCATTERING
SCINTILLATION COUNTERS
SUN
VARIATIONS