Caesium-134 has a
half-life of 2.0652 years. It is produced both directly (at a very small yield) as a
fission product, but not via
beta decay of other fission product
nuclides of mass 134, since beta decay stops at stable
Xe-134. It is also produced via
neutron capture from nonradioactive
Cs-133 (neutron capture
cross section 29
barns) which is a common fission product.
The combined yield of Cs-133 and Cs-134 is given as 6.7896%. The proportion between the two will change with continued neutron irradiation. Cs-134 also captures neutrons with a cross section of 140 barns, becoming long-lived radioactive Cs-135.
See also