Mean X-section Calculations
The % column is the percentage of the isotope in the natural element.
Each entry in the isotope column provides a link to the source of the information in the % and x-section columns.
N.B. Calculating weighted means to a few significant figures like this is straightforward when the individual values are very similar, as in these cases. More sophisticated methods are needed if they’re widely scattered.
| Isotope | % | Barns | Weighted Mean |
| 204Pb | 1.4 | 5.34 | 5.35 |
| 206Pb | 24.1 | 5.35 | |
| 207Pb | 22.1 | 5.35 | |
| 208Pb | 52.4 | 5.36 | |
| 9Be | 100 | 1.49 | 1.49 |
| 6Li | 7.5 | 1.43 | 1.47 |
| 7Li | 92.5 | 1.47 | |
| 54Fe | 5.85 | 2.50 | 2.57 |
| 56Fe | 91.75 | 2.57 | |
| 57Fe | 2.12 | 2.61 | |
| 58Fe | 0.28 | 2.66 |