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  2. Decay chain - Wikipedia

    en.wikipedia.org/wiki/Decay_chain

    The 4n+3 chain of uranium-235 is commonly called the "actinium series" or "actinium cascade". Beginning with the naturally-occurring isotope uranium-235, this decay series includes the following elements: actinium, astatine, bismuth, francium, lead, polonium, protactinium, radium, radon, thallium, and thorium. All are present, at least ...

  3. Actinium-225 - Wikipedia

    en.wikipedia.org/wiki/Actinium-225

    Actinium-225 (225 Ac, Ac-225) is an isotope of actinium. It undergoes alpha decay to francium-221 with a half-life of 10 days, and is an intermediate decay product in the neptunium series (the decay chain starting at 237 Np). Except for minuscule quantities arising from this decay chain in nature, 225 Ac is entirely synthetic.

  4. Actinium - Wikipedia

    en.wikipedia.org/wiki/Actinium

    The actinium isotope 227 Ac is a transient member of the uranium-actinium series decay chain, which begins with the parent isotope 235 U (or 239 Pu) and ends with the stable lead isotope 207 Pb. The isotope 228 Ac is a transient member of the thorium series decay chain, which begins with the parent isotope 232 Th and ends with the stable lead ...

  5. Uranium-235 - Wikipedia

    en.wikipedia.org/wiki/Uranium-235

    A critical chain reaction can be achieved at low concentrations of 235 U if the neutrons from fission are moderated to lower their speed, since the probability for fission with slow neutrons is greater. A fission chain reaction produces intermediate mass fragments which are highly radioactive and produce further energy by their radioactive decay.

  6. Isotopes of actinium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_actinium

    [12] [13] [14] Actinium-225 undergoes a series of three alpha decays – via the short-lived francium-221 and astatine-217 – to 213 Bi, which itself is used as an alpha source. [15] Another benefit is that the decay chain of 225 Ac ends in the nuclide 209 Bi, [note 1] which has a considerably shorter biological half-life than lead.

  7. Radium-223 - Wikipedia

    en.wikipedia.org/wiki/Radium-223

    Although radium-223 is naturally formed in trace amounts by the decay of uranium-235, it is generally made artificially, [9] by exposing natural radium-226 to neutrons to produce radium-227, which decays with a 42-minute half-life to actinium-227. Actinium-227 (half-life 21.8 years) in turn decays via thorium-227 (half-life 18.7 days) to radium ...

  8. Isotopes of lead - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_lead

    Lead (82 Pb) has four observationally stable isotopes: 204 Pb, 206 Pb, 207 Pb, 208 Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide.The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains: the uranium series (or radium series), the actinium series, and the thorium series, respectively; a fourth decay chain, the neptunium series ...

  9. Otto Hahn - Wikipedia

    en.wikipedia.org/wiki/Otto_Hahn

    The decay chain of actinium. Alpha decay shifts two elements down; beta decay shifts one element up. In 1913, chemists Frederick Soddy and Kasimir Fajans independently observed that alpha decay caused atoms to move down two places on the periodic table, while the loss of two beta particles restored it to its original position.