The ignored discovery of the element Z = 43 |
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| Institution: | 1. Nuclear Research Establishment, USA;2. Leuven University, SCK / CEN, B-2400 Mol, Belgium;1. Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;2. PRESTO (Precursory Research for Embryonic Science and Technology), Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;3. Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan;4. Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan;1. Laboratorio de Radiofarmacia, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Mataojo 2055, 11400 Montevideo, Uruguay;2. Centro de Investigação Translacional em Oncologia, Instituto do Câncer do Estado de São Paulo, Av. Dr. Arnaldo, 251, São Paulo 01246-903, Brazil;3. Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la Republica, Av. Alfredo Navarro 3051, 11600 Montevideo, Uruguay;4. Centro de Medicina Nuclear, Faculdade de Medicina, Universidade de São Paulo, Trav. R. Dr. Ovidio Pires de Campos s/n, São Paulo 05403-010, Brazil;5. Centro de Medicina Nuclear, Hospital de Clínicas, Facultad de Medicina, Universidad de la Republica, Av Italia s/n, 11600 Montevideo, Uruguay;6. Grupo de Química Medicinal, Laboratorio de Química Orgánica, Facultad de Ciencias-Facultad de Química, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay |
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| Abstract: | Until now Perrier and Segrè (Palermo, 1937) are credited for the first observation of the element Z = 43, called technetium (Tc). We give arguments for the statement that Walter Noddack, Ida Tacke and Otto Berg (Berlin, 1925) should be credited for the discovery of this element. In their search for the missing eka-manganese elements with Z = 43 and Z = 75 they observed the X-rays of these elements, with the peculiar behaviour though that the Z = 43 lines only appeared in ores, quoted to contain percentage quantities of uranium. The presence of element Z = 43 in uraniumcontaining ores can now be explained through the long-living fission product 9943 in their samples; they proposed the names masurium (Ma) and rhenium (Re) for the discovered elements. By reanalysing the original experimental conditions, we conclude that the detection limit for their observing the X-rays of Z = 43 can be 1000 times lower than the 10−9 detection limit for the element Z = 75. This brings us very close to the expected abundance of Z = 43 in the analysed samples, such that we do not see reasons for questioning the credibility of the experimental evidence. |
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