At 11:31 +1000 16/07/2002, Pat Naughtin wrote: >'The second is the duration of 9 192 631 770 periods of the radiation >corresponding to the transition between the two hyperfine levels of the >ground state of the caesium 133 atom. This definition refers to a caesium >atom in its ground state at a temperature of 0 K.' (The International System >of Units, BIPM 1998)
Please note that this definition was adopted in 1967 (13th CGPM). Louis
