What is the significance of radioactivity

Radioactivity is the main method of dating geological events at all space and time scales. It is an indirect tool for tracing the transfers in geological systems.

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Close Proceed. Export to Mendeley. Get permanent URL for this record. The process of gamma radiography, a type of non-destructive testing NDT , is used to validate the integrity of poured concrete and welds on fluid vessels, pipelines, or critical structural elements.

The unique characteristics of gamma radiography have resulted in the technique becoming a crucial tool throughout many industries. For example, to inspect new oil or gas pipelines, special film is taped over the weld around the outside of the pipe. A machine called a 'pipe crawler' carries a shielded radioactive source down the inside of the pipe to the position of the weld.

There, the radioactive source is remotely exposed and a radiographic image of the weld is produced on the film. This film is later developed and examined for signs of flaws in the weld. Gamma radiography has found use outside of core industrial applications, with the technique successfully employed following the devastating earthquake in Nepal in April NDT was used to test the integrity of critical buildings such as schools and hospitals, as well as historical attractions.

Researcher at Myanmar's Department of Atomic Energy testing equipment to be used in non-destructive testing. Gauges containing radioactive usually gamma sources are in wide use in all industries where levels of gases, liquids, and solids must be checked. The IAEA estimates that several hundred thousand such gauges are operating in industry worldwide.

They measure the amount of radiation from a source which has been absorbed in materials. These gauges are most useful where heat, pressure, or corrosive substances, such as molten glass or molten metal, make it impossible or difficult to use direct contact gauges.

The ability to use radioisotopes to accurately measure thickness is widely used in the production of sheet materials, including metal, textiles, paper, plastics, and others. Density gauges are used where automatic control of a liquid, powder, or solid is important, for example as in detergent manufacture.

There are two broad types of nucleonic gauges used in industry: fixed and portable. Fixed gauges are typically used in production facilities — mines, mills, oil and gas platforms — as a means of controlling and monitoring quality from a production process. For example, in the North Sea, fixed nucleonic gauges are sometimes deployed to determine conditions within separator vessels and to monitor residual oil content within separated gas streams.

Nucleonic gauges are also used in the coal industry. The height of the coal in a hopper can be determined by placing high energy gamma sources at various heights along one side with focusing collimators directing beams across the load. Detectors placed opposite the sources register the breaking of the beam and hence the level of coal in the hopper. Such level gauges are among the most common industrial uses of radioisotopes. Some machines which manufacture plastic film use radioisotope gauging with beta particles to measure the thickness of the plastic film.

The film runs at high speed between a radioactive source and a detector. The detector signal strength is used to control the plastic film thickness. When the intensity of radiation from a radioisotope is being reduced by matter in the beam, some radiation is scattered back towards the radiation source. The amount of 'backscattered' radiation is related to the amount of material in the beam, and this can be used to measure characteristics of the material.

This principle is used to measure different types of coating thicknesses. Portable gauges have applications in agriculture, construction, and civil engineering. These two water-soluble ions are separated by column chromatography, with the higher charge molybdate ion adsorbing onto the alumina in the column, and the lower charge pertechnetate ion passing through the column in the solution.

A few micrograms of Mo can produce enough Tc to perform as many as 10, tests. Radioisotopes can also be used, typically in higher doses than as a tracer, as treatment. A cancer patient may receive external beam radiation therapy delivered by a machine outside the body, or internal radiation therapy brachytherapy from a radioactive substance that has been introduced into the body. Note that chemotherapy is similar to internal radiation therapy in that the cancer treatment is injected into the body, but differs in that chemotherapy uses chemical rather than radioactive substances to kill the cancer cells.

The overall process is:. Radioisotopes are used in diverse ways to study the mechanisms of chemical reactions in plants and animals.

These include labeling fertilizers in studies of nutrient uptake by plants and crop growth, investigations of digestive and milk-producing processes in cows, and studies on the growth and metabolism of animals and plants. For example, the radioisotope C was used to elucidate the details of how photosynthesis occurs. The overall reaction is:. At regular intervals, the plants were analyzed to determine which organic compounds contained carbon and how much of each compound was present.

From the time sequence in which the compounds appeared and the amount of each present at given time intervals, scientists learned more about the pathway of the reaction. They include determining the thickness of films and thin metal sheets by exploiting the penetration power of various types of radiation. Flaws in metals used for structural purposes can be detected using high-energy gamma rays from cobalt in a fashion similar to the way X-rays are used to examine the human body.