Notable Isotopes 
133Cs [78 neutrons]
Abundance: 100%
Stable with 78 neutrons
134Cs [79 neutrons]Abundance: synthetic
Half life: 2.0648 years [ Electron Capture ]
Decay Energy: 1.229 MeVDecays to 134Xe.
Half life: 2.0648 years [ beta- ]
Decay Energy: 2.059 MeVDecays to 134Ba.
135Cs [80 neutrons]Abundance: trace
Half life: 2.3 x 106 years [ beta- ]
Decay Energy: 0.269 MeVDecays to 135Ba.
137Cs [82 neutrons]Abundance: synthetic
Half life: 30.07 years [ beta- ]
Decay Energy: 1.176 MeVDecays to 137Ba.
| 137Cs is produced from the detonation of nuclear weapons and is produced in nuclear power plants, and was released to the atmosphere most notably from the 1986 Chernobyl meltdown. |