# Decay Product

In nuclear physics, a decay product (also known as a daughter product, daughter isotope or daughter nuclide) is the remaining nuclide left over from radioactive decay. Radioactive decay often pickles a sequence of steps (decay chain). For example, U-238 decays to Th-234 which decays to Pa-234 which decays, and so on, to Pb-206 (which is stable):

$mbox{U-238} rightarrow overbrace{ underbrace{mbox{Th-234}}_{mbox{daughter of U-238}} rightarrow underbrace{mbox{Pa-234m}}_{mbox{granddaughter of U-238}} rightarrow ldots rightarrow mbox{Pb-206} }^{begin{array}{c} mbox{decay products of U-238} end{array}}$

In this example:

• Th-234, Pa-234m,…,Pb-206 are the decay products of U-238.
• Th-234 is the daughter of the parent U-238.
• Pa-234m (234 metastable) is the granddaughter of U-238.

These might also be referred to as the daughter products of U-238.

Decay products are important in understanding radioactive decay and the management of radioactive waste.

For elements above lead in atomic number, the decay chain typically ends with an isotope of lead.

In many cases members of the decay chain are far more radioactive than the original nuclide. Thus, although uranium is not dangerously radioactive when pure, some pieces of naturally-occurring pitchblende are quite dangerous owing to their radium content. Similarly, thorium gas mantles are very slightly radioactive when new, but become far more radioactive after only a few months of storage.

Although it cannot be predicted whether any given atom of a radioactive substance will decay at any given time, the decay products of a radioactive substance are extremely predictable. Because of this, decay products are important to scientists in many fields who need to know the quantity or type of the parent product. Such studies are done to measure pollution levels (in and around nuclear facilities) and for other matters.

### Other articles related to "decay, decay product, product":

Uranium-238 - Radium Series (or Uranium Series)
... Nuclide Historic name (short) Historic name (long) Decay mode Half-life MeV Decay product 238U U Uranium α 4.468·109 a 4.270 234Th 234Th UX1 Uranium X1 β- 24.10 d 0.273 234mPa 234mPa ... Similarly, in an equilibrium in a closed system the amount of each decay product, except the end product lead, is proportional to its half-life ... within a human timescale the equilibrium applies for the first three steps in the decay chain only ...
Actinide - Isotopes
... neptunium series it was first discovered in 1947 as a fission product of uranium-233, it is an α-emitter with a half-life of 10 days ... Actinium-228 is a member of radioactive thorium series formed by the decay of 228Ra it is a β– emitter with a half-life of 6.15 hours ... The most important isotopes are 231Pa and 233Pa, which is an intermediate product in obtaining uranium-233 and is the most affordable among artificial ...
Radon - Characteristics - Isotopes
... The most stable isotope is 222Rn, which is a decay product of 226Ra, a decay product of 238U ... The 220Rn isotope is a natural decay product of the most stable thorium isotope (232Th), and is commonly referred to as thoron ... No radon isotopes occur significantly in the neptunium (237Np) decay series ...

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