Gamma-ray multiplicity distribution in ternary fission of 252Cf

Abstract

From multiparameter data obtained at Lawrence Berkeley National Laboratory, the integral characteristics of the prompt γ-ray emission were extracted for tripartition of 252Cf with He, Be and C being the third light charged particle. We used multifold γ-ray coincidence spectra for the determination of γ-ray multiplicities assuming a Gaussian distribution for γ-ray multiplicity. The multiplicity distribution characteristics, i.e. mean multiplicity and its dispersion were obtained by minimizing with respect to the calculated values of probabilities of multifold γ-ray coincidences using a combinatoric method. Comparison with the known experimental data from binary fission was made. Further, we investigated dependencies of the mean γ-ray multiplicity on the kinetic energy of the light charged particle. The mean γ-ray multiplicity for He ternary fission is found to increase rapidly with increasing kinetic energy of He in the region less than 11 MeV and then decrease slowly with increasing kinetic energy of He. The anomalous behaviour of γ-ray emission is discussed. The mean γ-ray multiplicity was determined for the first time for Be and C ternary fission. For Be, the γ-ray multiplicity as a function of kinetic energy was obtained as well.