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Sources of Radiation
Published in Douglas S. McGregor, J. Kenneth Shultis, Radiation Detection, 2020
Douglas S. McGregor, J. Kenneth Shultis
Charged particles are directly ionizing radiations and, unlike photons and neutrons, have well-defined ranges as they interact with the long-range Coulombic forces of the atoms of the medium through which they pass. Such particles arise from several sources. Radioactive decay products almost always produce charged particles such as alpha and beta particles.5 Likewise, photon and neutron induced reactions with an atom usually produce secondary charged particles. Indeed it is these secondary charged particles that are used to detect the presence of these indirectly ionizing radiations. Finally in our technological modern world there are many machines that produce energetic charged particles. Indeed accelerators that produce energetic charged particles are used for a myriad of tasks such as industrial processing, production of medical radioisotopes, or numerous research purposes.
Electromagnetics in medicine
Published in James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney, Basic Introduction to Bioelectromagnetics, 2018
James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney
When radon, a radioactive gas, decays, it produces aerosols that are attracted to common sources of electric power such as appliances and power lines. It has been theorized that these decay products might also congregate in the human respiratory tract when a person is exposed to even relatively weak (1 kV/m) electric fields, thus increasing his or her risk of cancer.
Methods for Air Analysis
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
Radon, an inert radioactive gas, is a natural product of radioactive decay in rocks. It has a half-life of 3.8 days and produces short-lived decay products. It becomes an air pollution problem when it leaks from the soil or mineral-derived building materials such as cinder blocks or tiles, and collects inside dwellings. Radon-222 decays by emitting an alpha particle to form polonium 218, another alpha emitter, with a half-life of 3 minutes. A series of other daughter products are also formed, ending with a stable isotope of lead. The most lung-damaging isotope, however, is the alpha emitting polonium-218, as it is usually associated with a solid particle, and therefore can deposit in the lung where it will eventually decay.
Miracles, misconceptions and scotomas in the theory of solitary waves
Published in Geophysical & Astrophysical Fluid Dynamics, 2019
Segrè's “the eye does not see” is the bitter fruit of his own struggles. He and Fermi observed fission in 1934 but misinterpreted their experiments. They bombarded various elements with neutrons. For uranium, they found a decay product with a half-life of only 13 min. After chemical tests excluded the decay product from being any of the known elements heavier than lead, Fermi sent a note to Nature claiming discovery of the first transuranic elements. Ida Noddack, nee Tacke, (1896–1978), who had earned a doctorate in chemistry, argued that his chemical tests were insufficient; he needed to check for atomic numbers smaller than lead because nuclei might have fissioned. She was absolutely right, but her paper was universally ignored. (However, she and her husband Walter Noddack and a colleague named Otto Berg are credited with the discovery of rhenium in 1925.) Fermi and Segrè's ausonium and hesperium are now called neptunium and plutonium. Jeremy Bernstein, who chronicled this episode in Bernstein (2009, pp. 28–30), professes great astonishment that Fermi and Segrè falsely claimed to have discovered transuranics and missed fission. Hahn and Strassman did split uranium in 1938, but, like Fermi and Segrè, did not realise what their experiments meant until much later when Lise Meitner and her nephew Otto Frisch explained it to them.