STUDIES ON FALL-OUT PARTICLES. PART II.

Journal Article · Sat Dec 01 04:00:00 EST 1962 · Nippon Genshiryoku Gakkaishi (Japan)

OSTI ID:4759931

Mamuro, T; Yoshikawa, K; Matsunami, T; Fujita, A; Azuma, T

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

Related Subjects

BARIUM 140
CERIUM 141
CERIUM 144
DECAY
DISTILLATION
DISTRIBUTION
DUSTS
EFFICIENCY
FALLOUT
FAST NEUTRONS
FILTERS
FISSION
FISSION PRODUCTS
GAMMA SPECTROMETERS
GEOLOGY, MINERALOGY, AND METEOROLOGY
IODINE 131
LANTHANUM 140
NIOBIUM 95
PAPER
PARTICLES
QUANTITATIVE ANALYSIS
QUANTITY RATIO
RADIOACTIVITY
RADIOCHEMISTRY
RAIN
RUTHENIUM 103
SAMPLING
SEPARATION PROCESSES
URANIUM 238
WATER
ZIRCONIUM 95