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Particle decay series

Cochran JK (1984) The fates of U and Th decay series nuclides in the estuarine environment. In The Estuary as a Filter. Kennedy VS (ed) Academic Press, London, p 179-220 Cochran JK (1992) The oceanic chemistry of the uranium - and thorium - series nuclides. In Uranium-series Disequilibrium Applications to Earth, Marine and Environmental Sciences. Ivanovich M, Harmon RS (eds) Clarendon Press, Oxford, p 334-395 Cochran JK, Masque P (2003) Short-lived U/Th-series radionuclides in the ocean tracers for scavenging rates, export fluxes and particle dynamics. Rev Mineral Geochem 52 461-492 Cochran JK, Carey AE, Sholkovitz ER, Surprenant LD (1986) The geochemistry of uranium and thorium in coastal marine-sediments and sediment pore waters. Geochim Cosmochim Acta 50 663-680 Corbett DR, Chanton J, Burnett W, Dillon K, Rutkowski C. (1999) Patterns of groundwater discharge into Florida Bay. Linrnol Oceanogr 44 1045-1055... [Pg.601]

It has been found that the "unattached" fraction is an ultrafine particle aerosol with a size range of 0.5 to 3 nm. In order to initiate studies on the formation mechanism for these ultrafine particles, a series of experiments were made in the U.S. Bureau of Mines radon chamber. By introducing SO into the chamber, particles were produced with an ultrafine size distribution. It has been found that the particle formation mechanism is supressed by the presence of radical scavengers. These experiments suggest that radiolysis following the decay of Rn-222 gives rise to the observed aerosol and the properties of the resulting aerosol are dependent on the nature and the amount of reactive gas present. [Pg.368]

When thorium emits alpha particles, it disintegrates into other daughter radionuclides (radioactive materials), such as radium-226 and radon-222 (from thorium-230 in the uranium-238 decay series) or radium-228 and thoron (radon-220 from thorium-232 in the thorium decay series). It eventually decays to stable lead-208 or -206, which is not radioactive. More information about the decay of thorium can be found in Chapter 3. The toxicological characteristics of radon, radium, and lead are the subject of separate ATSDR Toxicological profiles. [Pg.27]

X 10 yr) and ends with stable ° Pb, after emission of eight alpha (a) and six beta (jS) particles. The thorium decay series begins with Th (ti/2 = 1.41 X 10 °yr) and ends with stable ° Pb, after emission of six alpha and four beta particles. Two isotopes of radium and Th are important tracer isotopes in the thorium decay chain. The actinium decay series begins with (ti/2 = 7.04 X 10 yr) and ends with stable Pb after emission of seven alpha and four beta particles. The actinium decay series includes important isotopes of actinium and protactinium. These primordial radionuclides, as products of continental weathering, enter the ocean primarily by the discharge of rivers. However, as we shall see, there are notable exceptions to this generality. [Pg.34]

Since spontaneous fission is extremely rare in Nature, detection of fission events in natural samples would give a strong hint. Alpha-particle spectra would be less specific, because the energies predicted for superheavy nuclei fell into the range covered by the natural decay series deriving from uranium... [Pg.293]

When the nucleus of a radioactive atom disintegrates, it emits various particles and so changes its own composition. When an alpha particle is lost then a new element is formed, which is two places to the left in the periodic table. When a beta particle is lost then a new element is formed which is one place to the right in the periodic table. Therefore, by a series of losses of alpha and beta particles, the element progressively changes. This is called decay , and the pattern it follows until a stable nuclear arrangement is reached (usually when the element lead is formed) is called the decay series (see Chapter 12). [Pg.243]

The two problems presented above show a type of transmutation not yet encountered in this book. In these problems an isotope is being bombarded with a particle to trigger the transmutation. This is called an artificial transmutation. This is different from the first four reactions examined, in which the isotopes underwent a natural transmutation and did not need to be bombarded with other particles to undergo a transmutation. The natural transmutations that Th-232 undergoes can be seen in the decay series shown in Figure 12.1. [Pg.178]

In each case, the final product must differ from the original parent hy some multiple of 4 mass numbers. Eor example, the 2° Ph differs in mass number from by 24 = 4 x 6. There must have been six alpha particles emitted in this decay series, with a reduction of four mass numbers each. (The beta and gamma particles emitted do not affect the mass number.)... [Pg.288]

TABLE 21.3 The Half-Lives of Nuclides in the Decay Series Nuclide Particle Produced Half-Life... [Pg.987]

The radioactive isotope 247Bk decays by a series of a-particle and j3-particle productions, taking 247Bk through many transformations to end up as 207Pb. In the complete decay series, how many a particles and /3 particles are produced ... [Pg.1007]

Holland and Gottfried (1955) studied the changes in density and unitcell dimensions as a function of the total a-particle dose D per milligram of zircon. D was estimated from the present a-activity and the Th/U ratio, together with the age T of the sample, on the assumption that equilibrium in the uranium and thorium decay series had been established in a time that was short compared with T. T was determined from the present a-activity and lead content (see Faure 1977). It was found that for )< 10, the density was approximately 4.7 g/cm. As the dose was increased, the density decreased slowly at first and then more rapidly, and finally approached asymptotically a value of approximately 3.95 g/cm. ... [Pg.280]

In all of these decay series, only a and p decay are observed. With emission of an y. particle (" Me) the mass number decreases by 4 units, and the atomic number by 2 units [A — A -A Z - Z - 2). With emission of a / " particle the mass number docs not change, whereas the atomic number increases by 1 unit A — A Z = Z + 1). These are the first and second displacement laws formulated by Soddy and Fajans in 1913. By application of the displacement laws it can easily be deduced... [Pg.29]

The final members of the decay series are stable nuclides ° Pb at the end of the thorium family, Pb at the end of the uranium-radium family, Pb at the end of the actinium family, and Bi at the end of the neptunium family. In all four decay series one or more branchings are observed. For instance, Bi decays with a certain probabihty by emission of an a particle into Tl, and with another probability by emission of an electron into Po. os-pj decays by emission of an electron into Pb, and Po by emission of an a particle into the same nuclide (Table 4.1), thus closing the branching. In both branches the sequence of decay alternates either a decay is followed by P decay or p decay is followed by a decay. [Pg.31]

Branching decay is often observed for odd-odd nuclei on the line of P stability. For example, °K, which is responsible for the natural radioactivity of potassium, decays into Ca with a probability of 89.3% by emission of particles and into Ar with a probability of 10.7% by electron capture. Branching decay is also observed in the decay series, as already mentioned in section 4.1. [Pg.42]

Geiger and Nuttall in 1911 found that the decay constants of the a emitters in the natural decay scries and the ranges R of the a particles in air are correlated for a certain decay series by equations of the form... [Pg.50]

Radionuclides in the uranium decay series serve as useful tracers of particle flux. One type of these tracers consists of a soluble parent nuclide and a particle-reactive daughter. These soluble nuclide-particle-reactive pairs include 234 j 230jjj and The half-life of the... [Pg.2954]

Several useful particle-reactive tracers are found within the natural uranium and thorium ( Th) decay series ... [Pg.3099]

Fundamental to the use of natural radionuclides as tracers of particle transport is an understanding of the rates and mechanisms of radionuclide transfer from solution into the particulate phase. In a closed system, where no mechanism exists for the physical separation of a daughter nuclide from its parent, the decay series reach steady state... [Pg.3100]

The major decay paths for the naturally occurring isotopes of uranium and thorium are shown in Table 1. Other actinides of environmental importance include Np, Pu, Pu, and " Am. These have decay series similar to and overlapping those of uranium and thorium. Neptunium-237 (fy2 = 2.14 X 10 yr, a) decays to ° Bi through a chain of intermediates, emitting seven a- and four j3 "-particles. Plutonium-238 (h/2 = 86 yr, a) decays into an intermediate daughter on the decay series. [Pg.4750]

Making and Using Graphs Thorium-231 decays to lead-207 in a stepwise fashion by emitting the following particles in snccessive steps 3, a, a, p, a, a, a, p, P, a. Plot each step of the decay series on a graph of mass nnmber versns atomic nnmber. Label each plotted point with the symbol of the radioisotope. [Pg.838]


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See also in sourсe #XX -- [ Pg.212 ]




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Decay series

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