Study of the Radioactivity of Hokutolite
Radioactive constituents and equllibria in the hot spring sediment Hokutolite were studied by determination of the activity ratio of U series to Th series. Investigation of natural radioactivity of the Hokutolite was examined in three portions, i.e., the Pb portion, Bi portion, and hydroxide portion. The various nuclides present in different portions were identified by following the growth and decay curves of the radioactivity of each portion. These three portions of Hokutolite were separated by either of two outlined procedures. For quantitative study the radioactive elements of the U series were determined by the absolute counting of Bi/sup 210/ and that of the Th series by absolute counting of AC/sup 228/. Since the BETA -ray energies of Ac/sup 228/ and Bi/sup 210/ ar e almost the same (1.11 and 1.17 Mev respectively), activities of both nuclides were determined by the constant geometry method, using Bi/sup 210/ as the reference source for BETA rays. Activities of the Bi and hydroxide portions were measured in hydroxide form. By analyzing the timeactivity curves it was possible to calculate the activity of Bi/sup 212/ at time (T) = 0 to be approximates 150 cpm (if Bi/sup 212/ is not separated from Pb/sup 212/ at T = 0) and the saturation activity of Bi/sup 210/ is about 390 cpm. Since the half life of Pb/sup 210/ is very long (11 yr), the saturation activity of Bi/sup 210/ would be about the same as that of Pb/sup 210/ at T = 0, if it were not separated from Pb/sup 210/. Therefore, the apparent activity ratio of U series to Th series is 380/150 = 2.5. In the hydroxide pontio the activity decayed with a half life of 6 hr to zero, and no other activity growth was observed afterwards. The only radioactive nuclide with a half life of 6 hr is Ac/sup 228/, which enables determination of the activity of Th series by the simple determination of Ac/sup 228/. In the Bi portion the analysis of the decay curve showed that it is composed of two sup 212/ and Bi/sup 210/ must be present. The activity of Bi/sup 210/ at T = 0 was obtained by extrapolation of the analyzed decay curve of Bi/sup 210/. Quantitative analysis of M/sub 2/O/sub 3/ from the hydroxide portion showed that the M/sub 2/O/sub 3/ content is 2.56%; thus, there is 78.8 mg of M/ sub 2/O/sub 3/ in 3 g of Hokutolite. Similarly, the Ra/sup 228/ content is 0.16 x 10/sup -13/ g/g Hokutolite. Since the activity of the hydroxide portion decayed in a simple fashion with a half life of 6 hr, and no other activity growth was observed, U and Th are absent from Hokutolite. Otherwise the activities due to U and Th together with their daughters should be observed in the hydroxide pontion. Thus, it is concluded that there are no equilibria between U/sup 238/ and Ra/sup 226/ between U/sup 235/ and Ra/sup 223/, or between Th/sup 232/ and Ra/su p 228/. The radioactive equilibrium originates from Ra, as is supported by the presence of Ac/sup 228/ the daughter of Ra/sup 228/. Since the radioactive series in Hokutolite originates from Ra, the presence of Ra/sup 226/(1822 yr), Ra/sup 228/(8.7 yr), and Ra/sup 223/(11.1 days) can be predicted. Since Ra/sup 228/ has a very short half life as compared with the history of the formation of Hokutolite, it is believed that if there had been any Ac series in hot spring water and in Hokutolite, their activity would have been exhausted in Hokutolite. (BBB)
- Research Organization:
- Tokyo Univ.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-001902
- OSTI ID:
- 4157658
- Journal Information:
- Journal of the Chinese Chemical Society, Vol. 9, Issue 1; Other Information: Orig. Receipt Date: 31-DEC-64; ISSN 0009-4536
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ACTINIUM
ACTINIUM 228
AGE ESTIMATION
BETA PARTICLES
BISMUTH 210
BISMUTH 212
DEPOSITS
ENERGY
HALF-LIFE
HYDROXIDES
LEAD 210
LEAD 212
MEASURED VALUES
PREPARATION
QUANTITATIVE ANALYSIS
RADIOACTIVITY
RADIUM
RADIUM 223
RADIUM 226
RADIUM 228
REACTION KINETICS
THORIUM
THORIUM 232
URANIUM
URANIUM 235
URANIUM 238
WATER