Gamma-ray sources

Half-life

Gamma-ray energy (keV)

Emission probability

G^* (mSv/hr-Ci at 1 m)

¹³⁷Cs

30 years

662

85%

33

¹⁹²Ir

74.2 days

296

308

317

468

589

604

612

29%

30%

81%

49%

4%

9%

6%

5

⁶⁰Co

5.26 years

1173

1332

100%

100%

133