Table 1.

Isotopic abundance of natural (recommended values [29]) and enriched selenium. The values for the enriched isotope are averaged over 70 different gas-to-metal conversion processes, weighted for their relative mass

	${}^{74}$Se	${}^{76}$Se	${}^{77}$Se	${}^{78}$Se	${}^{80}$Se	${}^{82}$Se
Natural Se (%)	0.87	9.36	7.63	23.78	49.61	8.73
Enriched Se (%)	$<$0.01	$<$0.01	$<$0.01	$<$0.01	3.67 $\pm$ 0.14	96.33 $\pm$ 0.31