Physics and Engineering of Radiation Detection

40 Chapter 1. Properties and Sources of Radiation

Table 1.6.1: Commonγemitters and their half lives.

Element Isotope Energy T 1 / 2

Sodium Na^24111. 368 MeV,2. 754 MeV 14.959 hours

Manganese Mn^5425834. 838 keV 312.3 days

Cobalt Co^60271. 173 MeV,1. 332 MeV 5.271 years

Strontium Sr^8538514. 005 keV 64.84 days

Yttrium Y 3988 898. 036 keV,1. 836 MeV 106.65 days

Niobium Nb^9441765. 803 keV 2. 03 × 104 years

Cadmium Cd^1094888. 034 keV 462.6 days

Cesium Cd^13755661. 657 keV 30.07 years

Lead Ph^2108246. 539 keV 22.3 years

Americium Am^2419526. 345 keV,59. 541 keV 432.2 years

with a half life of around 5.27 years (see Fig.1.6.7), as represented by the reaction
below.
60
27 Co→

60

28 Ni+β+ ̄ν+2γ (1.^17 MeV,^1.^33 MeV) (1.6.5)

(1.17 MeV)

(1.33 MeV)

Ni

Co

60

28

27

60

γ

γ

β(0.31 MeV max.)

Figure 1.6.7: Decay scheme of

cobalt-60.

Table 1.6.1 lists some of the commonly usedγ-ray sources and their half lives.