Distribution of nuclide

Given a number of nuclides at t = 0, calculate the distribution of nuclides in the U-Th decay series at any time t. 

FIGURE 19.9 The distribution of nuclides produced in the fission of has two peaks. Nuclei having mass numbers in the vicinity of A = 95 and A = 139 are formed with the highest yield those with A = 117 are produced with lower probability. 

Figure 1. The standard or solar system abundance distribution of nuclides, normalised to 10°...

Processes Affecting the Vertical Distribution of Nuclides in the Sediment Pile.153... 

Fig. 4. Mass distribution of the product of the 14N(35 MeV/u) + 197Au reaction [19]. Open circles indicate cumulative yields. The percentage is for the measured nuclides in the reaction products. The unit in the ordinate mb = 10 3 m 2...

Aerodynamic Size Distributions of Naturally-Radioactive Aerosols. Measurements of radionuclide distributions using cascade impactors indicate that Be-7 and Pb-210 are associated with larger aerosols than Pb-212 and Pb-214 (Robig et al., 1980 Papastefanou and Bondietti, 1986). Measurements of Pb-210 associations over oceans indicated activity median aerodynamic diameters (AMAD) near 0.6 pm (Sanak et al., 1981). The impactor measurements of Moore et al. (1980) on Pb-210, Bi-210, and Sr-90 sizes in continental air indicated that about 80% of the activity from all three nuclides was associated with aerosols below 0.3 pm. That work also determined that the mean age of aerosol Pb-210 was about a week. Knuth et al. (1983) compared Pb-210 and stable Pb sizes at a continental location and found that 78% of the Pb-210 found below 1.73 pm was smaller than 0.58 pm. Young (1974) reported that the most of the Be-7 in the atmosphere was associated with submicron aerosols. 

Three primary problem areas exist in dating groundwater. These are (1) Formulation of realistic geochemical-hydrodynamic models needed to interpret data which are generated by field and laboratory measurements, (2) development of sensitive and accurate analytical methods needed to measure trace amounts of various stable and unstable nuclides, and (3) theoretical and field oriented studies to determine with greater accuracy the extent and distribution of the subsurface production of radionuclides which are commonly assumed to originate only in the atmosphere. 

In this article we plan to focus on two aspects (i) the transport of radionuclides to the ocean floor and the processes which govern their distribution in deep-sea sediments and (ii) the application of deep-sea sediments to retrieve historical records of large scale phenomena, e.g. long term changes in the rate of production of nuclides by cosmic rays. Even while discussing these aspects, our emphasis will be mainly on the processes rather than on the details of the chronometric method. 

Thus the 13 C neutron source (with a little assistance from 22Ne) in thermally pulsing low- and intermediate-mass stars is well established as the chief source of the main component of s-process nuclides in the Solar System. It is not quite clear, however, whether the r0 parameter is something unique, or just the average over a more-or-less broad distribution of values nor is it clear why a similar s-process pattern is seen in stars that are metal-deficient by factors of up to 100 (see Pagel Tautvaisiene 1997). 

McNeill KG, Molla MA, Harrison JE. 1973. Distribution of thorium series nuclides in beagles after intraspinal Thorotrast injection. Health Phys 24 403-409. 

Fe- 60Ni system, direct measurements indicate that residual heterogeneity in the distribution of these short-lived nuclides is less than 10-15% (Thrane et al., 2006 Dauphas et al., 2008). 

Figure 1. Elemental distribution of fission waste nuclides on a sodium titanate column. The distribution shown on the left was determined from qualitative analyses of the numbered column segments. The Cs and Na distributions on the right were obtained by quantitative analyses of each numbered segment. (O), Cs ( ), Na.

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