In 1935, Einstein wrote a memoriam for the late Madame Marie Curie (1867-1934). She can be considered the first of the two radioactive women who were both awarded the Nobel Prize for Physics. The second was Maria-Goeppert-Mayer (1906-1972). Marie Curie devoted her life together with husband Pierre for research on the radioactive phenomena of matter discovered by Henri Becquerel in 1896. Within the lifespan of their researches, they discovered more than 40 radioactive elements and have removed almost all the mysteries surrounding radioactivity. In honor of her works, synthetic element with atomic number 96 was named curium. Incidentally, curium can be made from plutonium 239 by bombardment with helium ions accelerated in the cyclotron: ²³⁹Pu₉₄+He₂→Cm₉₆+n₀. The nuclide Cmis known as α-particle emitter with ½life about 5 months. Marie and Pierre Curie together with Henri Becquerel were awarded the 1903 Nobel Prize for Physics. Because of the danger of radioactive exposure, Madame Curie contracted a rare form of blood disease and suffered a painful death at the end of her life.
In 1963, Maria Goeppert-Mayer was also awarded the Nobel Prize for Physics recognizing her works with others concerning nuclear structures called the nuclear shell model. Although the validity of this model was quite questionable among physicists of the time, surprisingly, it was used successfully to explain not only the main features of the magic number phenomena, but also more detailed properties such as spins, magnetic moments, and level spectra of many nuclei. Incidentally, the magic numbers are a sequence of numbers which indicate nuclei stability when either the number of protons or the number of neutrons is equal to one of the following numbers: 2, 8, 14, 20, 28, 50, 82, and 126. Atomic nuclei consisting of such a magic number of nucleons have a higher average binding energy per nucleon than would be expected based upon calculations given by the semi-empirical mass formula, and hence are more stable against nuclear decay. The unusual stability of isotopes having magic numbers means that transuranium elements can be created with extremely large nuclei and yet not be subjected to the extremely rapid radioactive decay normally associated with high atomic numbers.


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