Radium, discovery measurements

Marie (NLP 1903, NLC 1911 ) and Pierre (NLP 1903 ) Curie took up further study of Becquerel s discovery. In their studies, they made use of instrumental apparatus, designed by Pierre Curie and his brother, to measure the uranium emanations based on the fact that these emanations turn air into a conductor of electricity. In 1898, they tested an ore named pitchblende from which the element uranium was extracted and found that the electric current produced by the pitchblende in their measuring instrument was much stronger than that produced by pure uranium. They then undertook the herculean task of isolating demonstrable amounts of two new radioactive elements, polonium and radium, from the pitchblende. In their publications, they first introduced the term radio-activity to describe the phenomenon originally discovered by Becquerel. After P. Curie s early death, M. Curie did recognize that radioactive decay (radioactivity) is an atomic property. Further understanding of radioactivity awaited the contributions of E. Rutherford. 

Since the discovery of radium compounds, many radio-active substances have been isolated. Only exceedingly minute quantities of any of them have been obtained. The quantities of substances used in experiments on radio-activity are so small that they escape the ordinary methods of measurement, and are scarcely amenable to the ordinary processes of the chemical laboratory. Fortunately, radio-activity can be detected and... 

The E-pH diagram for 10 M Ra is presented in Figure 6.6. This concentration is used because such a solution of the most long-lived radium isotope Ra-226 (half-life 1620 years) would be decaying at the rate of about 3 billion atoms per minute per liter. Such a radioactivity could be worked with given special apparatus and precautions, but more concentrated solutions would require more demanding measures. The discovery of the element Ra was in 1898 by Marie Sklodowska Curie, Pierre Curie, and M. G. Bemont who isolated its salts from large quantities of pitchblende. 

Measurement of radioactiviry, as an analytical tool became possible after the discoveries of A.H.Becquerel(uranium radiation 1896), Pi re Marie Curie (polonium radium in 1898), Sir E. Rutherford (identification of Becquerel rays as consisting of alpha-, beta and gamma-particles) and of F.Soddy(phenomenon of nuclear disintegration, in 1902)... 

Radon ( Rn) is the dominant source of human exposure to ionizing radiation in every country of the world. It is dominant in most circumstances at home and at work, for individual persons and for whole populations. The worst characteristic of radon, apart from its carcinogenicity, is its ubiquity. Before radon became a matter of concern for human exposure, it was studied and measured for many purposes. It was an inert tracer for air masses, it was a geological indicator for radium and uranium, and it was a shortlived source of y-radiation for cancer treatment. Radon plus beryllium was used as neutron source by Fermi for the discovery of neutron-induced fission reactions. 

X-rays fascinated the scientific community and the general public alike. Scientists investigated further and soon found related phenomena. Chief among these was a discovery made by Antoine-Henri Becquerel, a professor of physics in Paris. While studying the characteristics of fluorescent materials in March 1896, he discovered that uranium exposed a photographic plate when placed next to it. He had found another form of radiation, one that was emitted spontaneously from a natural substance. To investigate further, Becquerel collaborated with a husband-and-wife scientific team, Pierre Curie and Maria Sklodowska-Curie. Sklodowska-Curie devised an electrometer that could measure this radioactivity, as she called it, and studied a number of materials. In 1898 the trio managed to separate from uranium ore two radioactive elements polonium and radium. 

CURIE. A common unit of measurement for radioactivity. One curie is equal to 37 billion disintegrations per second or 37,000,000,000 becquerel, the metric unit for measuring radioactivity. The unit, abbreviated Ci, honors the Polish-French scientist Marie Curie (1867-1934), who is credited with coining the term radioactive. Curie and her husband Pierre (1859-1906) received the 1903 Nobel Prize in Physics in recognition of their investigations of radioactivity, sharing the award with Henri Becquerel. Marie Curie was also recognized with a second Nobel Prize, the 1911 award in Chemistry, for her discoveries of the elements radium and polonium. 

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