Electron spectroscopy at the high-energy endpoint of electron-nucleus bremsstrahlung

In electron-nucleus bremsstrahlung the incoming electron scatters inelastically off an atomic nucleus and transfers a fraction of its kinetic energy onto the emitted photon. The high-energy endpoint of electron-nucleus bremsstrahlung is of particular theoretical interest due to its close relation to photoionization PI and radiative electron capture REC, and provides most stringent tests for understanding the coupling between a matter field and an electromagnetic field. Experimentally this process is only accessible using inverse kinematics, where quasi-free target electrons scatter off fast highly charged heavy projectiles. In this case the electron can be understood as being radiatively captured into the continuum of the projectile (RECC). For collisions U88+ + N2 @ 90 MeV/u new measurements of the electron energy distribution in coincidence with the emitted photon have been conducted at the ESR, using the upgraded magnetic electron spectrometer. Furthermore electron energy distributions for non-radiative electron capture to continuum (ECC) and electron loss to continuum (ELC) could be determined.