 GNS
owns and operates New Zealand's National Isotope Centre. This facility,
in Lower Hutt, provides a wide range of isotope-based services to
New Zealand and many overseas countries.
Radioactive isotopes provide a powerful range of tools for both research and industrial measurement. Isotopes are forms of the same chemical element that vary in their atomic mass. They may be stable or unstable, decaying radioactively over time and emitting characteristic particles or radiation. These unstable isotopes are commonly called radioisotopes (more properly radionuclides). Isotopes can be used to study biological, agricultural and industrial processes, in archaeology, fisheries, ocean and atmospheric research, and in geological and environmental studies. Information can be gained from the relative amounts of stable isotopes, from the tracing of radioactive isotopes from the radiation emitted, and from the extent that a radioactive isotope has decayed into a more stable substance. For example, the short-lived radioisotopes carbon-11 and nitrogen-13 can be produced in the laboratory to investigate soil nitrogen processes and plant photosynthesis. Certain radioisotopes mimic the behaviour of components in industrial and natural processes. Tracing these radioisotopes is useful in the development of geothermal plants, environmental management, and the petrochemical industry. Leaks and blockages, flow rates and flow paths, and residence times in pipes can be discovered. Scientists also analyse hydrogen, oxygen, carbon, sulphur and tritium in groundwater to give information on aquifer storage capacity, aquifer recharge, and flow directions and velocities. Sources and age of groundwater can also be determined this way. Tracing the fluid flow in geothermal systems is important to reservoir management in developed geothermal fields. Isotope techniques using carbon, oxygen, hydrogen, sulphur and boron are used in field development to show flow direction and rate. Temperatures at depth can be predicted from isotopic measurements of geothermal gases and waters, as can their origin. The economic potential of natural gas fields may be shown by carbon dioxide variations in reservoirs. Measurements of sulphur, carbon and hydrogen isotopes help oil-to-oil and oil-to-source rock correlations. They also determine the origin of natural gases. Most importantly, isotopes can be used to date rocks and minerals, which in turn can provide important information about when geological events such as earthquakes and volcanic eruptions took place. Analysis of isotopes can also yield information about floods, tsunamis and even meteorite impacts.
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