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Science 18 March 1966:
Vol. 151. no. 3716, pp. 1381 - 1384
DOI: 10.1126/science.151.3716.1381
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Articles

Low-Energy Protons: Average Flux in Interplanetary Space during the Last 100,000 Years

D. Lal 1 and V. S. Venkatavaradan 1

1 Tata Institute of Fundamental Research, Colaba, Bombay 5, India

The radioactivity of aluminum-26 in two cores of Pacific sediments is an order of magnitude higher than was expected, as a result of its production by cosmic-ray interactions in the terrestrial environment. The higher activity can be explained only by postulating influx with extraterrestrial cosmic dust that had been exposed to significant flux of energetic particles capable of producing nuclear interactions. These particles may well be the "solar" cosmic rays that are sporadically accelerated by Sun during certain solar flares, since the steady galactic cosmic-ray flux is inadequate. The long-term average flux of low-energy protons in interplanetary space, required to yield the observed rate of influx of aluminum-26, is deduced on the basis of certain assumptions.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Aluminum-26 in Deep-Sea Sediment.
J. L. Reyss, J. L. REYSS, Y. YOKOYAMA, and S. TANAKA (1976)
Science 193, 1119-1121
   Abstract »    PDF »
Aluminum-26 and Beryllium-10 in Marine Sediment.
S. Tanaka, S. Tanaka, K. Sakamoto, J. Takagi, and M. Tsuchimoto (1968)
Science 160, 1348-1349
   Abstract »    PDF »
Influx Measurements of Extraterrestrial Material: Sea sediments, polar ice, air, and space are searched for amount and character of interplanetary debris.
D. W. Parkin, D. W. Parkin, and D. Tilles (1968)
Science 159, 936-946
   PDF »
Aluminum-26 and Beryllium-10 in Greenland Ice.
R. McCorkell, R. McCorkell, E. L. Fireman, and C. C. Langway Jr. (1967)
Science 158, 1690-1692
   Abstract »    PDF »
Zodiacal Dust and Deep-Sea Sediments.
S. F. Singer (1967)
Science 156, 1080-1083
   Abstract »    PDF »
Aluminum-26 in Pacific Sediment: Implications.
J. T. Wasson, J. T. Wasson, B. Alder, and H. Oeschger (1967)
Science 155, 446-448
   Abstract »    PDF »
Implantation in Interplanetary Dust of Rare-Gas Ions from Solar Flares.
D. Tilles and D. Tilles (1966)
Science 153, 981-984
   Abstract »    PDF »


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