STUDIES ON FALL-OUT PARTICLES. PART II. (in Japanese)
Results obtained by gamma spectrometry about the so-called fractioniltion effect (viz., that the radiochemical composition of highly radioactive fall-out particles is different from that of average fission products). Gamma spectra are shown of a filter-paper on which air-borne dusts were collected on Nov. 8, 1961, and of a highly radioactive particle found at that time. The radiochemical composition of the particle is strongly enriched in Zr/sup 95/ + Nb/sup 95/ and impoverished in Ru/sup 103/, Ba/sup 140/ + La/sup 140/ , I/sup 131/, and Ce/sup 141/ + Ce/sup 144/. Decay characteristics are shown of radioactivity of highly radioactive particles. Fractionation factors are calculated for many highly radioactive particles. The yield values for fast fission of U/sup 238 are used on carrying out the calculation of fractionition factors. Twenty-one of the highly radioactive particles are isolated from among non-radioactive dust particles. Relation is shown between particle radioactivity and fractionation factor for Ce/sup 141/ + Ce/sup 144/, showing that particles of larger ridioactivity are more affected by the fractionation effect. Fractionation factors for Ru/sup 103/ are smaller than 0.1 for all the particles and those for Ce/sup 141/ + Ce/sup 144/ are smaller than 0.6 for almost all of the particles. the fractionation effect is the most remarkable for Ru/sup 103/ and seems to extend to much smaller particles for Ru/sup 103/ than for Ce/sup 141/ + Ce/sup 144/. An example is given showing the fractionation effect observed in rain water. From the test sample of small quantity in which the fractionation effect is remarkably observed, may be obtained a higher measured value of the concentration of fallout than that obtained from an average sample of much larger quantity. (auth)
- Research Organization:
- Radiation Center of Osaka Prefecture
- NSA Number:
- NSA-17-012470
- OSTI ID:
- 4759931
- Journal Information:
- Nippon Genshiryoku Gakkaishi (Japan), Journal Name: Nippon Genshiryoku Gakkaishi (Japan) Vol. Vol: 4; ISSN NGEGA
- Country of Publication:
- Country unknown/Code not available
- Language:
- Japanese
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EFFICIENCY
FALLOUT
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FISSION
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URANIUM 238
WATER
ZIRCONIUM 95