Radioactive Decay Calculation

放射性衰变计算

The radioactive half-life for a given radioisotope is a measure of the tendency of the nucleus to "decay" or "disintegrate" and as such is based purely upon that probability. Alternatively, this information can be expressed in terms of the decay constant λ. The number of atoms, the mass of the substance, and the level of activity all follow the same exponential decay form. The calculation below is stated in terms of the amount of the substance remaining, but can be applied to intensity of radiation or any other property proportional to it.

某种放射性同位素的半衰期是衡量其核“衰变”或“分解”倾向的量度，因此它纯粹基于这种概率。或者，这一信息也可以用衰变常数λ来表达。原子数目、物质的质量以及活动水平都遵循相同的指数衰减形式。下面的计算是基于剩余物质的量进行的，但也可以应用于辐射强度或任何与其成正比的其他性质。

If the radioactive half-life of an isotope is
T = x10^ s = min = hr
T = yr = x10^ yr

若某同位素的放射性半衰期为 T = x10^ s = min = hr T = yr = x10^ yr

中文译文中的待填/计算数值依次对应：1：thb 2：thp 3：thm 4：thh 5：thy 6：thyb 7：thyp。实际数值以上方原输入框为准。

and amount A₀ is present at time t=0 and amount A remains at time t, then

= x10^ s = min
= 10^s × min
中文译文中的待填/计算数值依次对应：1：tb 2：tp 3：tm。实际数值以上方原输入框为准。
t = hr = yr = x10^ yr

当时间t=0时存在量A₀，而时间t时仍存在量A，则t = hr = yr = x10^yr

中文译文中的待填/计算数值依次对应：1：th 2：ty 3：tyb 4：typ。实际数值以上方原输入框为准。

the fraction remaining will be given by

剩余的分数将由以下公式给出

= = x10^

If the beginning amount was Ci* then the amount remaining is Ci

如果初始量为Ci，则剩余的量为Ci

中文译文中的待填/计算数值依次对应：1：ai 2：af。实际数值以上方原输入框为准。

This calculation is designed for exploration. It is presumed that you will enter a half-life for a particular radioisotope. Then if you enter a time, then it will calculate the fraction remaining at that time. If you enter a fraction or amount remaining, it will calculate the time required (or age) required to achieve that fraction.

*The amount is listed in Ci (Curies), but the mass, intensity of radiation, number of counts or other ways of characterizing the radioisotpe will decrease by the same ratio, so the calculation can be used for any of those quantities.

该量以居里（Ci）表示，但放射性同位素的质量、辐射强度、计数数或其他表征方式将按相同比例减少，因此该计算可适用于任何这些量。

Graph of decay

衰变图

Half-life discussion

半衰期讨论

此计算旨在进行探索。假设你输入某种放射性同位素的半衰期。然后如果你输入一个时间，它将计算该时间点剩余的分数。如果输入剩余的分数或数量，它将计算达到该分数所需的时间（或年龄）。

Index

索引

HyperPhysics***** Nuclear

HyperPhysics ***** 核物理

R Nave

Go Back

计算模块中未附着于文字的输入框：

中文译文中的待填/计算数值依次对应：1：a 2：ab 3：ap。实际数值以上方原输入框为准。