Multiplicity and Correlated Energy of Gamma Rays Emitted in the Spontaneous Fission of CALIFORNIUM-252.

An array of eight high-speed plastic scintillation detectors has been used to infer a mathematical model for the emission multiplicity of prompt gammas in the spontaneous fission of ('252)Cf. Exceptional time resolution and coincidence capability permitted the separation of gammas from fast neutrons over a flight path of approximately 10 cm. About 20 different distribution models were tested; the best (termed "double Poisson") was:. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). For a gamma threshold of 140 keV, the model with parameters evaluated reads:. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). The average energy of the prompt gammas is inversely related to the number emitted; however, this inverse relationship is not strong and the total gamma energy does increase with increasing gamma number. An extension of the experiment incorporated a lithium-drifted germanium gamma spectrometer that resolved nearly 100 discrete gammas associated with fission. Of these gammas, some were preferentially associated with fission in which few gammas were emitted. Certain others were more frequent when many gammas were emitted.