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Several fluorescent molecules can be used simultaneously (given that they do not overlap, cf. FRET), whereas with radioactivity two isotopes can be used (tritium and a low energy isotope, e.g. 33 P due to different intensities) but require special equipment (a tritium screen and a regular phosphor-imaging screen, a specific dual channel ...
Naturally occurring radioactive materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM) consist of materials, usually industrial wastes or by-products enriched with radioactive elements found in the environment, such as uranium, thorium and potassium and any of their decay products, such as radium and radon. [1]
The additional radioactivity in the biosphere caused by human activity due to the releases of man-made radioactivity and of Naturally Occurring Radioactive Materials (NORM) can be divided into several classes. Normal licensed releases which occur during the regular operation of a plant or process handling man-made radioactive materials.
Radon in air forms a part of the background radiation, which can be observed in a cloud chamber. Most of the dose is due to the decay of the polonium (218 Po) and lead (214 Pb) daughters of 222 Rn. By controlling exposure to the daughters the radioactive dose to the skin and lungs can be reduced by at least 90%. This can be done by wearing a ...
Most natural transmutation on the Earth today is mediated by cosmic rays (such as production of carbon-14) and by the radioactive decay of radioactive primordial nuclides left over from the initial formation of the Solar System (such as potassium-40, uranium and thorium), plus the radioactive decay of products of these nuclides (radium, radon ...
Radioactive decay is a random process at the level of single atoms. According to quantum theory, it is impossible to predict when a particular atom will decay, regardless of how long the atom has existed. [2] [3] [4] However, for a significant number of identical atoms, the overall decay rate can be expressed as a decay constant or as a half-life.
Natural isotopes are either stable isotopes or radioactive isotopes that have a sufficiently long half-life to allow them to exist in substantial concentrations in the Earth (such as bismuth-209, with a half-life of 1.9 × 10 19 years, potassium-40 with a half-life of 1.251(3) × 10 9 years), daughter products of those isotopes (such as 234 Th, with a half-life of 24 days) or cosmogenic ...
Tritium is the only radiation source used in radioluminescent light sources today due to its low radiological toxicity and commercial availability. [3] Various preparations of the phosphor compound can be used to produce different colors of light. For example, doping zinc sulfide phosphor with different metals can change the emission wavelength ...