Ernest Rutherford and his contribution in radioactivity
Ernest Rutherford is termed as the Father of Radioactivity and nuclear science. Rutherford, who born in 1871 and passed on in 1937, discovered alpha and beta rays. He set forth the law of radioactive decay, identified the alpha particles as helium nuclei. Rutherford postulated the nuclear structure of an atom. His contribution to Radioactivity came from an experiment he demonstrated by firing alpha particles into gas atoms where few particles were seen to deflect. This implied a dense, positively changed central region of an atom contained an atomic mass (Dardo, 2004).
Figure 1. Top: expected results, alpha particles passing undisturbed through a pudding model of an atom. Bottom: actual results, small portion of the rays is deflected, showing a concentrated charge.
Rutherford was the first scientist to design an experiment with high-frequency, alternating currents. In his paper, Magnetic Viscosity he described a time-apparatus capable of counting and measuring time spans of a hundred-thousandth of a second. Ernest invented a detector for electromagnetic waves while studying at Cambridge University. During his scientific journey, he collaborated with J.J Thomson. Rutherford and Thomson studied the behavior of ions as observed in gases treated with X-rays and the nobility of the ions about influence by an electric field. Rutherford in 1898 that there existed alpha and beta rays in the radiation of uranium and indicated particular properties of the radiations. He further studied “emanation” of thorium and found a new noble gas, an isotope of radon. It was later named as thoron (Rutherford, Chadwick, & Ellis, (2010).
Rutherford was joined by another scientist, Fredrick Soddy in 1900 where they collaborated to research on transmutation of elements. Ernest demonstrated that radioactivity was a spontaneous disintegration of atoms and noticed that a sample of a radioactive material invariably spent an equal amount of time for half of the sample to decay – half life. He created a practical for the phenomenon using the rate of decay as a clock to be used to determine the actual age of the earth. Upon his inauguration as a professor of physics at the University of Manchester in 1907, Rutherford collaborated with Ernest Marden and Hans Geiger to do an experiment that discovered the nuclear nature of atoms. In 1919, he transmuted an element to another by converting nitrogen into oxygen through a nuclear reaction. This is shown by formula 1 below
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He also theorized about the existence of neutrons that could compensate for the repelling effect of positively-charged protons by causing the attractive nuclear force and keeping the nuclear from breaking apart.
Weathering, a contributor to the mobilization of uranium.
During low-temperature chemical weathering, there is a significant mobilization and loss of uranium. The remaining uranium is redistributed among three modes. The background uranium is depleted while the mobilized uranium is adsorbed by the interstitial aggregates increasing their concentration. Resistate uranium is depleted as zircon, monazite, and acicular apatite retained initial concentrations but reduced in modal abundance (Nagy, 1983). Significant loss of uranium during weathering introduce potential secondary sedimentary mineralization implying the weathered granitoid rocks are not the appropriate elements in the geological barrier for nuclear waste. Uranium-rich igneous plutons liberate uranium during weathering and are sources of important secondary sedimentary deposits. Production of the deposits depends on the primary abundance of uranium in the source rocks, intensity of weathering, and extent of removal from the source (Australian Atomic Energy Commission, 1962).
The Uranium Unconformity Deposits have high grades about other deposits of uranium and consist of some of the richest deposits ever known. These deposits occur in proximity to main unconformities between relatively sandstones comprising the basal portion of undeformed sedimentary basins and the deformed metamorphic basement rocks. The sedimentary basins are of Proterozoic age. Proterozoic unconformity-related deposits occur in the metasediments beneath an unconformity at the base a surface Phanerozoic sandstone. The strata-bound structure-controlled deposits are low-grade chitrial and the Lambapur Deposits, Cuddapah basin in India. Uraninite and pitchblende are the main minerals that are associated by strong dissolution of quartz.
Figure 2. Australia: uranium mineralized Cahill Formation visible in pit uncomfortably overlain by Kombolgie sandstone.
Uranium Roll Front Deposits are hosted within permissible and porous sandstones or conglomerates. The dissolution of uranium from the formation and transport of the soluble uranium is the mechanism of formation of the deposits. During the redox state transformation, uranium precipitates to form the front in contact with carbon-concentrated organic matter. Roll Front Deposits represent the largest deposits of sandstone-hosted uranium. In this type of deposits, significant examples are Inkai deposit in Kazakhstan and Smith Ranch in Wyoming. Roll front deposits are advantageous of having low-cost in-situ leach recovery (Heilbron, 2003).
Roll Front Deposits have some typical features: crescent-shaped bodies that transect the host lithology, the convex side points down the hydraulic gradient, ore-bodies have interlocked rolls, the individual deposits are relatively small, the collectively extend for considerably long distances.
Figure 3. South Australia: palaeo-roll fronts structures
Consultation for the construction of v hotel-resort in the South Mountain Batholith (SMB)
The first step in the determination of radon and radioactivity in SMB started with the collection of mineral related information. For the objective of analysis the map grid incorporated in the department’s registry of mineral was utilized as a base (Sturn, 1997). The claims of the researchers were assessed for mineral related values that included: i) Number of times each claim was staked; ii) whether the claim was of a mineral lease, non-mineral registration or mining permit area; iii) whether the claim had an exploration drill hole, an open quarry that had been abandoned, previous or current producing mine, big pit or large quarry; iv) whether that claim was underlain by the Windsor Group, that is deemed to have a high potential of minerals based on historic mineral production for radon and uranium; v) peat deposits presence; vi) presence of industrial minerals, presence of mineral domains.
Data from this procedure was grouped into wide themes then presented in 3 sets of open file maps. These included exploration and mining activity, the open file map; mineral occurrences and deposits; and aggregate resources, open file map.
If little amount of radon was found in this place, little hazards or none will be expected in building the resort if measures are taken. The basement of the building must be established with strong building materials that prevent radiations. Building materials like thick concrete and steel will save the hotel visitors and patrons from dangerous radiations (Drever, 2005).
Lastly, the article discusses great work of Ernest Rutherford in the invention of radioactivity; how weathering and mobilization of uranium and how to determine Uranium in a site. It is important to note that uranium is very dangerous, exposure can lead to ill-health or even ultimate death if the exposure is so much serious.
References
Australian Atomic Energy Commission. (1962). Uranium in Australia: A collection of all articles on the history and the development of the uranium mining industry in Australia. Sydney.
Dardo, M. (2004). Nobel laureates and twentieth-century physics. Cambridge, Angleterre ; New York: Cambridge University Press.
Drever, J. I. (2005). Surface and ground water, weathering, and soils. Amsterdam: Elsevier.
Gray, D. J. (1986). The geochemistry of uranium and thorium during weathering of chloritic schists at the Alligator Rivers Uranium Province, N.T., Australia.
Heilbron, J. L. (2003). Ernest Rutherford: And the explosion of atoms. New York: Oxford University Press.
Nagy, B., IGCP Project 157., & IGCP Project 160. (1983). Developments and interactions of the Precambrian atmosphere, lithosphere, and biosphere. Amsterdam: Elsevier.
Rutherford, E., Chadwick, J., & Ellis, C. D. (2010). Radiations from radioactive substances. Cambridge [u.a.: Cambridge Univ. Press.
Sturn, R. A. (1997). The uranium weathering rate as an indicator of uranium mobility in contaminated soil.
