Parent nuclide, radioactive decay

Calorimetry. Radioactive decay produces heat and the rate of heat production can be used to calculate half-life. If the heat production from a known quantity of a pure parent, P, is measured by calorimetry, and the energy released by each decay is also known, the half-life can be calculated in a manner similar to that of the specific activity approach. Calorimetry has been widely used to assess half-lives and works particularly well for pure a-emitters (Attree et al. 1962). As with the specific activity approach, calibration of the measurement technique and purity of the nuclide are the two biggest problems to overcome. Calorimetry provides the best estimates of the half lives of several U-series nuclides including Pa, Ra, Ac, and °Po (Holden 1990). 

Figure 1. (a) Schematic representation of the evolution by radioactive decay of the daughter-parent (N2/N1) activity ratio as a function of time t after an initial fractionation at time 0. The initial (N2/Ni)o activity ratio is arbitrarily set at 2. Time t is reported as t/T2, where T2 is the half-life of the daughter nuclide. Radioactive equilibrium is nearly reached after about 5 T2. (b) Evolution of (N2/N1) activity ratios for various parent-daughter pairs as a function of time since fractionation (after Williams 1987). Note that the different shape of the curves in (a) and (b) is a consequence of the logarithmic scale on the x axis in (b). 

Suppose the initial number of nuclei of a radioactive nuclide is N0, and that the half-life is T. Then the amount of parent nuclei remaining at a time t can be written as Nx = NQ( /2)(tlT>. This relationship is called the radioactive decay equation. What is the number of daughter nuclei present at time t, expressed in terms of N0 and Nx ... 

In case of nuclides for which the input into the box is only due to their i n situ production from radioactive decay of their parents, equation (3) modifies to ... 

Write the nuclear equation for the radioactive decay of potassium-40 by beta emission. Identify the parent and daughter nuclides in the decay. 

In the above radioactive decays, a parent nuclide shakes itself to become another nuclide or two nuclides. A unidirectional arrow indicates that there is no reverse reaction or if there is any reverse reaction, it is not considered. He produced by the homogeneous reaction (radioactive decay) may subsequently escape into another phase, which would be another kinetic process. 

The first term on the right-hand side is the melting term the second term on the right-hand side is the radioactive decay of the nuclide and the last term on the right-hand side represents the radiogenic production by the parent of the nuclide. and Cj" are the concentrations of the nuclide... 

Daughter The term is used to describe the nuclide formed by the radioactive decay of another nuclide, which in this context is called the parent. 

Geochronological measurements (isochrone methodology) are based on the radioactive decay of the parent nuclide to the daughter nuclide using the fundamental Equation (8.8) for calculating the ages of minerals. 

Since the rock was formed, the parent nuclidic content of the mineral has been changed only by radioactive decay. 

The radioactive decay scheme of the parent nuclide is well known. 

During radioactive decay an unstable atomic nucleus emits radiation in the form of particular particles or electromagnetic waves. This process results in a parallel loss of energy as so-called parent nuclide(s) transform into daughter nuclide(s). The principal types of radioactive decay are alpha (a), beta (ft) and gamma (y), as described further in Table 10.1 the SI unit of radioactive decay is the Becquerel (Bq), where one Bq is one decay (or transformation disintegration) per second. 

Where Nq is the number of atoms of the radioactive species at the time of formation of the system under study, N is the amount left after a time t, and A is the decay constant. Where the ratio of the daughter to parent nuclide is measured after a time t has elapsed, then the equation becomes... 

A radionuclide, upon undergoing disintegration of a particular type, yields a specified nuclide. The original radionuclide is called the parent and the decay product is called the daughter. The daughter may also be a radionuclide. A succession of nuclides, each of which transforms by radioactive disintegration into the next until a stable nuclide results, is called a radioactive series. Examples of such series are the uranium series and the thorium series. 

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