衰变产物

由铅212至铅208的衰变链

在原子核物理学中，衰变产物(也称至子同位素)是一个元素经过辐射衰变后剩下来的核素。辐射衰变通常涉及很多过程(衰变链)。例如，铀238(U-238)衰变至钍234(Th-234)，钍234(Th-234)再衰变成镤234(Pa-234)，而镤234(Pa-234)再衰变成…，再衰变成铅206(Pb-206)（稳定）:

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

$v$

在这例子中，

• 钍234，镤234m，…，铅206是铀238的衰变产物；
• 钍234是铀238的至子同位素；
• 镤234m (234 metastable)是铀238的[至孙同位素][?]。

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.