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  2. Radioactive decay - Wikipedia

    en.wikipedia.org/wiki/Radioactive_decay

    Recent results suggest the possibility that decay rates might have a weak dependence on environmental factors. It has been suggested that measurements of decay rates of silicon-32, manganese-54, and radium-226 exhibit small seasonal variations (of the order of 0.1%).

  3. Radium - Wikipedia

    en.wikipedia.org/wiki/Radium

    226 Ra is the most stable isotope of radium and is the last isotope in the (4 n + 2) decay chain of uranium-238 with a half-life of over a millennium; it makes up almost all of natural radium. Its immediate decay product is the dense radioactive noble gas radon (specifically the isotope 222 Rn ), which is responsible for much of the danger of ...

  4. Radium-226 - Wikipedia

    en.wikipedia.org/wiki/Radium-226

    The decay-chain of uranium-238, which contains radium-226 as an intermediate decay product. 226 Ra occurs in the decay chain of uranium-238 (238 U), which is the most common naturally occurring isotope of uranium. It undergoes alpha decay to radon-222, which is also radioactive; the decay chain ultimately terminates at lead-206. Because of its ...

  5. Environmental radioactivity - Wikipedia

    en.wikipedia.org/wiki/Environmental_radioactivity

    Radium and radon are in the environment because they are decay products of uranium and thorium. The radon (222 Rn) released into the air decays to 210 Pb and other radioisotopes, and the levels of 210 Pb can be measured. The rate of deposition of this radioisotope is dependent on the weather. Below is a graph of the deposition rate observed in ...

  6. Radium and radon in the environment - Wikipedia

    en.wikipedia.org/wiki/Radium_and_radon_in_the...

    Radium, like radon, is radioactive and is found in small quantities in nature and is hazardous to life if radiation exceeds 20-50 mSv/year. Radium is a decay product of uranium and thorium. [2] Radium may also be released into the environment by human activity: for example, in improperly discarded products painted with radioluminescent paint.

  7. Radon - Wikipedia

    en.wikipedia.org/wiki/Radon

    Discussions of radon concentrations in the environment refer to 222 Rn, the decay product of uranium and radium. While the average rate of production of 220 Rn (from the thorium decay series) is about the same as that of 222 Rn, the amount of 220 Rn in the environment is much less than that of 222 Rn because of the short half-life of 220 Rn (55 ...

  8. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206. Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation. The accompanying table shows the ...

  9. Radon-222 - Wikipedia

    en.wikipedia.org/wiki/Radon-222

    Radon-222 (222 Rn, Rn-222, historically radium emanation or radon) is the most stable isotope of radon, with a half-life of approximately 3.8 days. It is transient in the decay chain of primordial uranium-238 and is the immediate decay product of radium-226.