Th. doct.--Ecol.--Montpellier 2, 1990. N°: 0274. / Résumé en anglais. Bibliogr. p. 146-159.

Thesis (Ph. D.)--University of Michigan, 1940. / "Reprinted from the Physical review, vol. 60, no. 3 ... August 1, 1941."

Thesis (Ph. D.)--University of Chicago, 1921. / "Private edition, distributed by the University of Chicago libraries." Part II, by Herbert N. McCoy and Leo Finkelstein.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

A thin-lens beta-ray spectrometer is described and a brief analysis of its operation is given. A coincidence Geiger-Mueller counter to be used with this instrument is also described. The spectrometer has been calibrated with a line of the thorium B spectrum, and used to obtain beta-ray spectra of radium E and antimony 124. The experimental spectra have been found to agree well with those previously published. Several methods of plotting beta-ray spectra are described and applied to radium E and antimony 124. From the Fermi plot the endpoint of the radium E spectrum appears to be at 1.18 Mev, from the van der Held plot at 1.16 Mev. For antimony 124 four endpoints have been determined from the Fermi plot at .50, .65, .90 and 2.43 Mev. It is shown that the van der Held plot reduces to the Fermi plot for this spectrum. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The first part of this thesis describes measurements made with medical radium sources to determine the ratio of the exposure in a large (essentially infinite) water "phantom" to the exposure at the same point in air, i.e., to determine the fractional transmission in an "infinite" water phantom. The fractional transmission was measured as a function of the distance between the radium sources and the measuring instrument. The radium used was sealed in platinum containers which absorbed the primary alpha and beta rays from the radium so that the exposures were due to gamma rays only. All measurements were made with small air-filled ionization chambers with plexiglass walls. Ionization currents were measured with these chambers in water and in air. The corrections which were required to determine the ratio of exposure in water to exposure in air from these measurements and the preliminary experiments necessary to determine the required corrections are described in the thesis. The fractional transmission through water is shown graphically as a function of the distance between source and point of measurement. Also, the relationship is described by an empirical equation. The curve drawn fits the experimental points obtained under a variety of conditions of measurement within the experimental error of 1/2 to 1%. The second part of the thesis describes measurements of ionization currents made with an experimental set-up in which the ionization chamber was at a fixed distance vertically below the radium and the whole assembly was moved relative to the surface of a water phantom. From measurements made with the radium above the surface, in the surface and below the surface of the water, it was possible (a) to obtain data which could be compared with the results of Part I and (b) to obtain correction factors which could be applied to the results of Part I to correct for reduced scatter when the radium was in the surface, rather than well immersed in water. The results of the present experiment are compared with those of previous workers. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

From the moment Marie Curie announced the existence of radium, the strange new element captured the imagination of the American public. Radium, it seemed, could do anything. It gave off its own light and heat and appeared to realize the ancient alchemical dream of transmutation. It also showed promise as a medicine. The press ran with the idea that radium was a panacea that would cure everything from cancer to wife-beating. Soon it became impossible for the public to know what to believe when it came to radium and its effects on the body. Patent medicine companies exploited the murkiness surrounding ideas about radium, marketing a slew of products that claimed to harness the element’s healing and energizing powers. Meanwhile, physicians made slow, careful progress in defining the parameters of radium therapy, narrowing their focus to cancer. The popularity of radium patent medicines peaked in the 1920’s when hundreds of thousands of Americans purchased one or more of the dozens of radium products that proliferated at the time. Government regulators and members of the medical establishment sought to push these products from the market, but loopholes in the regulatory apparatus created under the Pure Food and Drug Act of 1906 allowed many of these companies to operate freely. Two scandals—the saga of the “Radium Girls” and the death of Eben Byers, a well-known industrialist who died after drinking over 1000 bottles of a radioactive tonic called Radithor—damaged radium’s image in the 1920’s and 1930’s. By the late 1930’s, strengthened regulatory laws helped push radioactive products from the marketplace. During World War II, scientists discovered artificial isotopes that proved more effective and less expensive than radium in the treatment of disease. For decades Americans had struggled to make sense of a scientific discovery that seemed to challenge fundamental ideas about the nature of the body and its relationship to the physical world. The ambiguities surrounding the element posed a unique challenge to progressive ideals of expertise and professionalization while providing a malleable image of energy and health that a variety of commercial interests could deploy. / text

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Soil that is contaminated with radioactive elements poses an exposure hazard to those whom may take up temporary or permanent residence on such a site. Of particular interest is the internal exposure from ingestion of this radioactive soil. Although most ingestion of soil is inadvertent, usually being attached to foodstuffs that are not properly cleaned, it is possible that a person might consume a larger quantity. Childhood soil ingestion from simple hand-to-mouth activities is one explanation for this larger intake, as well as geophagia (eating dirt) or pica (craving and eating non-food items). The assumption that any person might consume a "mouthful" of dirt is a rare but possible occurrence that, when analyzed, will help with decisions about safe contamination levels of soil. Samples of soils contaminated with radium-226 were sent from an engineering and environmental firm to Oregon State University's Department of Nuclear Engineering and Radiation Health Physics for assessment. The analysis of the samples was aimed at the determination of bioavailability and bioaccessibility of the radioactive species found in the soils. Subsequent site remediation actions for the New Jersey-based project would be partially dictated by the results of Oregon State University's testing. Initially, the soils were tested for the presence of carbonates, for leachability of radioactivity in water and in acid, and for particle size distribution, i.e., soil type. Each of the eight samples was then subjected to a stomach/intestinal analogue to determine how much of the radioactivity would be transferred to solution upon human ingestion, (bioaccessibility). Mass balance and gamma spectrometry outputs for the soil samples before and after the digestion was one way the loss to solution was assessed. Another method to determine the loss of radioactivity to solution was to count aliquots of the digestive fluids in a high purity germanium detector, using a library of only radium isotopes and their progeny to locate peaks. The combination of results from mass balance and gamma spectrometry outputs allowed for OSU's researchers to determine the bioaccessibility of each soil's radioactive components. Using the determined bioaccessibility and previous animal models, the determination of bioavailability varied between the samples, from zero to 28% of the total initial radioactivity in the samples. A hot particle estimation of the dose from the non-bioavailable portion of the samples yielded a high dose to a small number of cells. Assuming ingestion of the most radioactive sample, (Sum-03a), the amount of damaged (killed) tissue in each section of the gastrointestinal tract was estimated to be less than 0.0407 cm³. This small volume of tissue is not likely to result in evident damage as the healthy human gastrointestinal tract regenerates all surface cells approximately every six days and most items are resident in the digestive system for less than 48 hours. / Graduation date: 2006