FINE-STRUCTURE EFFECT IN THE RELATIVISTIC (E,2E) PROCESS

Using a transversely polarized electron beam a relativistic (e,2e) exp eriment has been performed to look for a spin-up-spin-down asymmetry i n the electron-impact ionization process caused by the fine-structure effect. An incident energy of 300 keV, coplanar asymmetric kinematics, and the 2p(3/2) Shell of uranium (Z=92) have been used. We found clea r evidence for the fine-structure effect in the relativistic regime an d a qualitative agreement with theoretical results of the relativistic distorted-wave Born approximation, including a change of sign in the angular distribution of the asymmetry near the Bethe ridge. [S1050-294 7(98)50710-X].