Radiative-electron-capture-to-continuum cusp in U~(88+) + N_2 collisions and the high-energy endpoint of electron-nucleus bremsstrahlung

摘要

The radiative electron capture of a target electron into the projectile continuum has been studied for the collision system U~(88+) + N_2 → U~(88+) + [N_2~+]* + e~? + γ at 90 MeV/u. Using a magnetic electron spectrometer, the energy distribution of cusp electrons emitted under an angle of 0? with respect to the projectile beam and with a velocity close to the projectile velocity has been measured in coincidence with the emitted photons under various observation angles. The experimental results provide a stringent test for the corresponding process in inverse kinematics, namely, the theory of electron-nucleus bremsstrahlung at the high-energy endpoint. For comparison this process is calculated using fully relativistic Dirac wave functions and using semirelativistic Sommerfeld-Maue wave functions.