First decay

Write a nuclear equation for each of the following transformations (a) 25 Rf produced by the bombardment of califomium-245 with carbon-12 nuclei (b) the first synthesis of 266Mt by the bombardment of bismuth-209 with iron-58 nuclei. Given that the first decay of meitnerium is by a emission, what is the daughter nucleus ... 

A specific form of this equation was solved by Barnes et al. (1956) when he presented the first decay counting °Th data for corals. The equation of Barnes et al. (1956) did not include the second term on the right side... 

The same kind of optimization has been performed for the thoron daughters. In the calculations the sampling period was set at 30 min and the first decay time interval is started after the decay of the radon daughters (270 min). For a total measurement time of 16 hours the optimized MMC of Pb-212 and Bi-212 are respectively 0.02 Bq/m and 60 Bq/m (270-370 min, 540-960 min). Better results for Bi-212 are obtained with only one decay time interval and an estimation of the ratio of Pb-212 to Bi-212 out of the removal processes (ventilation and deposition of the attached thoron daughters). The influence of the removal rate on the potential alpha energy concentration is small. For the decay interval (270-960 min) the MMC of Pb-212 is 0.014 Bq/m, assuming the sum of the removal rates to be 0.6+0.5/h. 

The probability that the first decay takes place before t is therefore the complement of this expression to one since... 

The cumulative distribution function of the time T to the first decay is... 

We can now distinguish three general cases, depending on whether the first decaying species has a longer, a much longer, or a shorter half-hfe than that of the daughter nuclide. These three cases are transient equilibrium, secular equilibrium, and nonequilibrium. 

Radon is a naturally occurring radioactive decay product of uranium. A great deal of attention 222 228 centers around radon, which is the first decay product of radium. Radon and radon... 

Since the half-life estimated by dynamic ESR studies is in the order of 10 min, we assume that the first-decaying component is assigned to the triplet carbene, while the slower decaying one is assigned to a secondary product formed during the decay pathway of the triplet carbene. Thus, a triplet carbene having a lifetime over several minutes was realized for the hrst time. ... 

In diagram B, the future first decays fast, and then more slowly ... 

Using y-y coincidence relations, the first decay scheme of Tb Gd is... 

A reanalysis of all decay chains measured at SHIP since 1994, a total of 34 decay chains was analyzed, revealed that the previously published first decay chain of277112 [30] (not shown in Figure 3) and the second of the originally published four chains of 269110 [29] were spuriously created. Details of the results of the reanalysis are given in [19]. 

The overall decay curve of ESR signal with time after a sample is exposed to ambient air encompasses two major types of decay. The initial decay immediately after the sample is exposed to ambient air is usually very fast, starting with the first-order decay and deviating from the first decay as the decay rate slows down. Thus, the entire decay curve cannot be expressed by one decay-kinetic mechanism. 

A series of nuclear reactions that begins with an unstable nucleus and results in the formation of a stable nucleus is called a radioactive decay series. As you can see in Figure 25-11, uranium-238 first decays to thorium-235, which in turn decays to protactinium-234. Decay reactions continue until a stable nucleus, lead-206, is formed. 

The term CAH is used in the following as a synonym for chlorinated aliphatic hydrocarbons , e.g., tetrachloroethene, trichlorethene, trichloroethane TCE is also the first decay product of PCE... 

Fig. 8. The Fourier time transform of an electronic transition. The first decay period (neglecting the small undulations, which are not real) is about 3.5 x 10 sec, corresponding to a line width (I/wt) of about 30 cm .

The isolated contains some formed through reactions indicated in Figure 20.3. Since the half-life of is rather short and its decay products even shorter lived, a considerable y-activity will grow in with the U stock, complicating its handling. Since the first decay product is Th, some Th forms in the fuel elemmts, making the Th contaminated by this isotope. Thus neither the nor the Th produced can be free from y-activity. 

Radon-222, the first decay product of Ra, is an alpha-particle emitter with a 3.82 day half-life. A sample of Rn gas was found to have an activity of 2.22 x 10 disintegrations per minute, (a) What is its activity in microcuries (b) What is the decay constant in sec" (c) How many atoms of Rn does the sample contain (d) How many grams (1 curie = 3.70 x 10 dps.)... 

The first decay channel, Mb, is a rapidly decaying function of time describing the effects of essentially uncorrelated binary collisions, which is well known and is the only relaxation mechanism in the traditional kinetic theories of gases. The second mechanism M, which is often referred to as the non-binary collision term, is the most important outcome of the generalized kinetic theory, and accounts for additional slow processes coming from correlated collisional effects. 

The first decay-constant systematics proposed is called the Geiger-Nuttall rule (see Eq. (2.60) in Chap. 2). This rule, set up originally as a decay-constant - alpha-range relationship, can be readily converted into the following half-life - alpha-energy relationship ... 

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