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  2. Half-life - Wikipedia

    en.wikipedia.org/wiki/Half-life

    There is a half-life describing any exponential-decay process. For example: As noted above, in radioactive decay the half-life is the length of time after which there is a 50% chance that an atom will have undergone nuclear decay. It varies depending on the atom type and isotope, and is usually determined experimentally. See List of nuclides.

  3. Decay energy - Wikipedia

    en.wikipedia.org/wiki/Decay_energy

    The molar weight is 59.93. The half life T of 5.27 year corresponds to the activity A = N [ ln(2) / T ], where N is the number of atoms per mol, and T is the half-life. Taking care of the units the radiation power for 60 Co is 17.9 W/g Radiation power in W/g for several isotopes: 60 Co: 17.9 238 Pu: 0.57 137 Cs: 0.6 241 Am: 0.1 210 Po: 140 (T ...

  4. Radioactive decay - Wikipedia

    en.wikipedia.org/wiki/Radioactive_decay

    Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha, beta, and gamma decay.

  5. Radioactivity in the life sciences - Wikipedia

    en.wikipedia.org/wiki/Radioactivity_in_the_life...

    Not all molecules in the solution have a P-32 on the last (i.e., gamma) phosphate: the "specific activity" gives the radioactivity concentration and depends on the radionuclei's half-life. If every molecule were labelled, the maximum theoretical specific activity is obtained that for P-32 is 9131 Ci/mmol.

  6. List of radioactive nuclides by half-life - Wikipedia

    en.wikipedia.org/wiki/List_of_radioactive...

    This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.

  7. Exponential decay - Wikipedia

    en.wikipedia.org/wiki/Exponential_decay

    The biological half-lives "alpha half-life" and "beta half-life" of a substance measure how quickly a substance is distributed and eliminated. Physical optics : The intensity of electromagnetic radiation such as light or X-rays or gamma rays in an absorbent medium, follows an exponential decrease with distance into the absorbing medium.

  8. Radionuclide - Wikipedia

    en.wikipedia.org/wiki/Radionuclide

    Radioactive nonprimordial, but naturally occurring on Earth. 61 347 Carbon-14 (and other isotopes generated by cosmic rays) and daughters of radioactive primordial elements, such as radium, polonium, etc. 41 of these have a half life of greater than one hour. Radioactive synthetic half-life ≥ 1.0 hour). Includes most useful radiotracers. 662 989

  9. Valley of stability - Wikipedia

    en.wikipedia.org/wiki/Valley_of_stability

    According to Byrne, [3] stable nuclides are defined as those having a half-life greater than 10 18 years, and there are many combinations of protons and neutrons that form nuclides that are unstable. A common example of an unstable nuclide is carbon-14 that decays by beta decay into nitrogen-14 with a half-life of about 5,730 years: 14 6 C → ...