Observation of Large and Strongly Energy Dependent Directional Anisotropies in NoncharacteristicKX Rays Emitted in Heavy-Ion Collisions

The existence of directional anisotropies in quasimolecular K-x-ray emission has been independently confirmed in experiments on the C-C, O-C, Al-Al, and Si-Al collision systems. Anisotropies ranging from zero to substantially larger values than measured by Greenberg, Davis, and Vincent for the Ni-Ni system are strongly dependent on beam energy (0.06-2 MeV/amu). The C-C and O-C anisotropies decrease with energy. The Al-Al and Si-Al anisotropies increase with energy, in accord with a dependence predicted theoretically.