Some isotopes are radioactive and are called radioisotopes. By bombarding the nucleus of an atom with protons, neutrons, and alpha particles, radioactive isotopes can be obtained artificially. For example, bombardment of the nucleus of the aluminum atom with alpha particles, the following nuclear reaction can occur, in which the reaction product is a radioactive isotope of phosphorus. Artificial methods to obtain radioisotopes have been in agriculture and industry, health and scientific research and many other aspects of a wide range of applications.
The application of radioisotopes is along the following two directions.
1. Using its rays
Radioisotopes can also emit alpha rays, alpha rays and alpha rays. alpha rays due to the penetration of strong ability, can be used to check the metal inside there is no trachoma or cracks, the equipment used is called alpha ray detector. alpha rays of the ionization effect is very strong, can be used to eliminate the machine in the operation of the friction and the harmful static electricity. alpha rays can be used in the operation of the machine in the operation of the machine in the friction and the static electricity. Organisms within the DNA (deoxyribonucleic acid) carries the genetic code of the species, but the DNA may be mutated under the action of rays, so the seeds can be mutated by radiation exposure to cultivate new varieties. Ray radiation can also inhibit the growth of crop pests, and even directly eliminate pests. Cancer cells in the human body are more sensitive to radiation than normal cells, so radiation can be used to treat malignant tumors, which is what doctors call "radiation therapy".
Compared with natural radioactive materials, artificial radioisotopes are easy to control the intensity of radiation, but also can be made into a variety of desired shapes, in particular, its half-life is much shorter than that of natural radioactive materials, so radioactive waste is easy to dispose of. Because of these advantages, in production and scientific research wherever the use of rays, the use of man-made radioisotopes, not natural radioactive material.
2. As a tracer atom
A radioactive isotope of the nucleus and the nucleus of other isotopes of the element have the same number of protons (only the number of neutrons is different), and therefore the number of electrons outside the nucleus is also the same, which can be seen, a variety of isotopes of the element have the same chemical properties. In this way, we can use radioactive isotopes instead of non-radioactive isotopes to make a variety of compounds, the compounds of atoms with the same as the usual compounds to participate in all chemical reactions, but with "radioactive markers", can be detected with instruments. These atoms are called tracer atoms.
Cotton needs more phosphorus fertilizer when it bears peasants and flowers, and the phosphorus fertilizer can be absorbed by spraying it on the cotton leaves. However, when the absorption rate is the highest, phosphorus can be stored in the crop body for how long, the distribution of phosphorus in the crop body, etc., with the usual method is difficult to study. If the radioactive isotope of phosphorus made of fertilizer sprayed on the cotton foliage, and then every certain time with a detector to measure the intensity of radioactivity in various parts of the cotton plant, the above problem will be easy to solve.
The human thyroid gland needs iodine to work. Iodine is absorbed and collects in the thyroid gland. The radioactive isotope of iodine, iodine 131, is injected into a person, and then a detector is used at regular intervals to measure the intensity of radioactivity in the thyroid and neighboring tissues, which can help to diagnose organic and functional diseases of the thyroid gland.
In recent years, the study of the structure of biological macromolecules and their functions, almost always with the help of radioisotopes.