On symmetric tripartition in the spontaneous fission of 252Cf

Angular and energy distributions of ternary fission products of 252Cf have been measured with a position sensitive ionization chamber. Most of the observed triple coincidences are light-charged-particle accompanied fission events. The few events registered with relative angles near 1200 allow to deduce an upper limit of 10-8 per binary fission for a symmetric ternary fragmentation, in contradiction to previous counting experiments yielding ternary-to-binary fission ratios between 10-4 and 10-6. (orig.)