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Cantone, M.C.; Cornolti, E.; Bartolo, D. de; Giussani, A.; Tsipenyuk, Yu. M.; Firsov, V. I.; Gorbunov, A. V.

doi:10.1023/a:1010626504718

Cited by 6 publications

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“…A 50-to 70-mg sample and a reference sample (graphite or AlN) were placed in a container; the container was then delivered to the microtron irradiation chamber at the Institute for Physical Problems of the Russian Academy of Sciences [3,4] using a pneumatic rabbit system. The container in this case was arranged at 3 cm from the bremsstrahlung target; therefore, 70% of the gamma quanta passed through the sample, and the specific activity of the analyte attained a maximum.…”

Section: Determination Of Carbon and Nitrogen In Meteorites Using Gammentioning

confidence: 99%

Determination of carbon and nitrogen in meteorites using gamma-ray activation analysis

2005

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Carbon and nitrogen concentrations and their distribution in meteorites are depend both on the conditions of asteroid formation (asteroids are the main source of meteorites) and on the subsequent processes on these bodies. Among such processes are the shock transformations of asteroid substances upon their collisions in the cosmic space. Shock transformation are accompanied by a number of effects, among which we can distinguish blackening, which is believed to relate to metal and troilite (FeS) fusion, and the dispersion of the fused substance over microcracks in minerals [1]. However, it was supposed in [2] that the blackening of the meteorite substance (ordinary chondrites) is due to the post-shock gaseous activity on asteroids, the meteorite's parent ARTICLES Abstract -The volume concentration of carbon and nitrogen in different meteorites was determined by gamma-ray activation analysis on a microtron. The 11 C and 13 N radionuclides forming in photoneutron reactions were isolated by high-temperature extraction; their positron activity was then deactivated by the method of gamma-gamma coincidence of annihilation gamma quanta. A clear correlation was found between the sample darkness and the carbon concentration; the latter was at a level of 10 -2 wt %. No correlations was observed for nitrogen; its concentration was one order of magnitude lower than that of carbon and varied over the range (2-6) × 10 -3 wt %. The results obtained suggest that carbon entered different structural defects in chondrites as a result of its redistribution upon gaseous activity on parent bodies. Determination of carbon and nitrogen concentrations in meteorites by gamma-ray activation analysisMeteorite origin and color Concentration of carbon, n × 10 2 , wt % Concentration of nitrogen, m × 10 3 , wt % Reflection factor R , rel. units Gorlovka 7.2

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Section: Determination Of Carbon and Nitrogen In Meteorites Using Gammentioning

confidence: 99%