Irene và Frederic Joliot Curie Năm 1934, Irene Joliot Curie (con gái của Marie Curie) và chồng cô, Frederic Joliot, đã thành công trong việc đưa ra một đồng vị phóng xạ mà không xảy ra trong tự nhiên. Họ bắn phá một tấm nhôm với α-hạt từ một nguồn phóng xạ tự nhiên, và khi họ loại bỏ các nguồn hạt α, nó xuất hiện rằng các tấm nhôm bức xạ phát ra với một nửa cuộc sống của khoảng 3 phút. Lời giải thích là sự bắn phá đã dẫn đến một phản ứng hạt nhân. . | Chapter 5 Artificial Radioactive Isotopes The Discovery In 1934 Irene Joliot Curie Marie Irene and Frederic Joliot Curie Curie s daughter and her husband Frederic Joliot succeeded in making a radioactive isotope that does not occur in nature. They bombarded an aluminum plate with a-particles from a natural radioactive source and when they removed the a-particle source it appeared that the aluminum plate emitted radiation with a half-life of approximately 3 minutes. The explanation was that the bombardment had resulted in a nuclear reaction. The a-particle penetrated the aluminum nucleus and changed it into phosphorus by emitting a neutron. The new phosphorus isotope was radioactive and was responsible for the observed radiation. Its designation is P-30. Berkeley National Laboratory University of California Berkeley courtesy AIP Emilio Segrè Visual Archives This nuclear reaction is written as follows a 30P n. The neutron emitted can be observed as long as the bombardment takes place but disappears immediately when the a-source is removed. However the phosphorus isotope is radioactive and emits a positron with an energy of MeV which can easily be measured and a half-life of minutes. 2003 Taylor Francis 40 Radiation and Health In the mid 1930 s several laboratories had developed equipment to accelerate protons and a-particles to high energies. When these elementary particles were used as projectiles to bombard stable atoms new isotopes were formed. Some of these isotopes were radioactive. Another very efficient particle used in these experiments was the neutron. This particle has no charge and will consequently not be influenced by the electric field around the atomic nucleus. The neutron readily penetrates the atom forming new isotopes. Reactors are excellent sources of neutrons and are used for the production of radioactive isotopes needed for biomedical research and the treatment of disease. The number of artificial isotopes increased rapidly in the years
