Positron production in 238U + 232Th and 238U + 181Ta collisions near the Coulomb barrier has been studied. Earlier experiments reported narrow lines in the spectra of positrons, accumulated without the requirement of electrons detected in coincidence. No evidence of such structure is observed in the present data. The positron energy spectra are compared with estimates from dynamic atomic processes, and from internal pair conversion of electromagnetic transitions from the excited nuclei.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)