| nNs |
| Ni |
where ln = the natural logarithm (log to the base e), Ns = the number of atoms in the sample. Ni = the number of atoms of ²³⁵U in the irradiated sample,
and the constant has the value:
½
| λα × 582 × 10⁻²⁴ |
| λf × 137.7 |
Fission-track dating is a brand new technique, still only partly developed. It has enormous range and is applicable to numerous minerals; these advantages imply that it is likely to become very useful.
An atomic absorption spectrophotometer is used to measure the amount of potassium in samples of mica dissolved in acid.
Plumbology
The most complicated and therefore probably the most interesting decay scheme of all is the decay of uranium to lead, discovered well over half a century ago and still intensively studied. There are several reasons for the interest.