Thorium-228 (Th-228)

Identity

Protons

90

Neutrons

138

Mass number

228

Mass

228.0 ± 1.9 u

Mass excess

26.771 MeV

Spin

0+

Stability

Half-life: 1.91 years

Natural occurrence

Not found in nature

Decays to

• alpha → Ra-224

Produced by

• U-232