Angular momenta of fission fragments in the α-accompanied fission of ²⁵²Cf

For the first time, average angular momenta of the ternary fission fragments Zr-100,Zr-102, Mo-106, Ba-144,Ba-146 and Xe-138,Xe-140,Xe-142 from the alpha-accompanied fission of Cf-252 were obtained from relative intensities of prompt gamma-ray transitions with the use of the statistical model calculation. Average values of the angular momenta were compared with the corresponding values for the same fission fragments from the binary fission of Cf-252. Results indicate the presence of a decreasing trend in the average values of angular momenta induced in ternary fission fragments compared to the same binary fission fragments. On the average, the total angular momentum extracted for ternary fission fragments is similar to 1.4 h lower than in binary fission. Consequently, results indicate that the mechanism of the ternary a-particles emission may directly effect an induction of angular momenta of fission fragments, and possible scenarios of such mechanisms are discussed. Further, the dependence of the angular momenta of Mo-106 and Xe-140 on the number of emitted neutrons from correlated pairs of primary fragments was obtained also showing a decreasing dependence of average angular momenta with increasing number of emitted neutrons. Consequences are briefly discussed.