Trace Sciences International

Gadolinium Isotopes

Nominal Mass
Accurate Mass
% Natural Abundance
Chemical Form
Enrichment Available %

152 Gd

151.919786 (4)

0.20 (1)

oxide

30 – 34+

154 Gd

153.920861 (4)

2.18 (3)

oxide

64 – 67+

155 Gd

154.922618 (4)

14.80 (12)

oxide

90 – 92+

156 Gd

155.922118 (4)

20.47 (9)

oxide

93 – 95+

157 Gd

156.923956 (4)

15.65 (2)

oxide, chloride

87 – 99+

158 Gd

157.924019 (4)

24.84 (7)

oxide

97+

160 Gd

159.927049 (4)

21.86 (19)

oxide

98+

Gadolinium Isotopes have the highest cross section for the capture of thermal neutrons of any element and this is mainly due to the high cross section of Gd-157 (255,000 barn) and Gd-155 (61,000 barn). Natural Gadolinium is currently used as a burnable poison in nuclear fuel, but the use of Gd-155/157 only has been proposed as this would create an even more effective burnable poison. Gd-152 is used for the production of radioactive Gd-153 which is used for osteoporosis research and bone density measurements. Gd-160 is used in double beta decay research and for the production of the mecdical isotope Tb-161.