COSMIC-RAY PRODUCTION RATES OF Be$sup 7$ IN OXYGEN, AND P$sup 32$, P$sup 33$, S$sup 35$ IN ARGON AT MOUNTAIN ALTITUDES

Journal Article · Wed Jun 15 04:00:00 EDT 1960 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.118.1626· OSTI ID:4185771

Lal, D; Arnold, J R; Honda, M

The prcduction rates of radioisotopes P/sup 32/, P/sup 33/ and S/sup 35/ in argon, and of Bel in oxygen were measured by exposing argon and water to cosmic rays at mountain altitudes for periods of two to four months during 1958. The measured values at lambda = 51 deg N, atmospheric depth 685 g cm/sup -2/ were 7.6 x 10/sup -6/, 6.2 x 10/sup -6/, 1.4 x 10/sup -5/ atoms (g angon)/sup -1/ sec /sup -1/ of P/sup 32/ P/sup 33/ and S/sup 35/ respectively, and 9.0 x 10/sup - 6/ Be/sup 7/at oms (g oxygen)/sup -1/ sec/sup -1/. lsotope prcduction rates for all regions in the atmosphere were recently calculated by Lal et al. The measured prcduction rates were higher than the calculated rates by factors of 1.1, 1.8, 1.4, and 1.8 in the case of radioisotopes Be/sup 7/, P/sup 32/, P/sup 35/, and S/sup 35/ respectivel y. In this comparison, account was taken of the fact that cosmic-ray intensity decreased by about 15% since 1948, the time pericd to which the calculations apply. The measured production rates in oxygen were assumed to apply to air since cross sections for Bel formation were found to be the same in nitrogen and oxygen over most of the energy region of interest. The procedure used by Lal et al. yielded a fuirly accurate picture of the variation in prcduction rates with altitude and latitude in the atmosphere. Isotope prcduction rates in all regions of the atmosphere could, therefore, be obtained by normalizing their calculations at the points where the measurements were made. The calculated prcduction rates of these isotopes in the tropesphere, and in the stratosphere corresponding to observed cosmic-ray intensity during 1948-49, were given. The available data on the concentration of the isotopes in rain-water and their averaged yearly deposition rates were compared with their revised production rates. From such a comparison, more definite conclusions could be drawn than hitherto possible in view of the more accurate knowledge of isotope prcduction rates. (auth)

• Research Organization: Scripps Institution of Oceanography, La Jolla, Calif.
• NSA Number: NSA-14-018332
• OSTI ID: 4185771
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 118; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ARGON
ATMOSPHERE
BERYLLIUM 7
COSMIC RADIATION
CROSS SECTIONS
ENERGY RANGE
FALLOUT
INTERACTIONS
LEVELS
MEASURED VALUES
NITROGEN
NUMERICALS
OXYGEN
PHOSPHORUS 32
PHOSPHORUS 33
PHYSICS
PRODUCTION
RADIOACTIVITY
RADIOISOTOPES
RAIN
STRATOSPHERE
SULFUR 35
VARIATIONS
WATER