Large gamma anisotropy observed in the 252Cf spontaneous-fission process.

The energy spectrum and the angular dependence relative to the fission direction of photons in the energy region between 2 and 40 MeV have been measured for the spontaneous fission of Cf-252. A large anisotropy was found in the energy region 8 to 12 MeV implying that photons in this region are emitted from a nuclear system which is highly elongated along the fission axis.