STUDIES OF SYNCHROTRON RADIATION EMISSION FROM THE MODIFIED BETATRON ACCELERATOR

Numerical calculations of synchrotron radiation emitted from the modified betatron accelerator show that, for relativistic electron energies up to approximately 2 MeV, the single‐particle intensity spectrum is characterized by a peak at the Doppler‐shifted cyclotron frequency associated with the applied toroidal field. As the electron energy is increased above a few MeV, the calculated spectrum becomes comparable to that of an electron in purely circular motion. Measurements of the radiation using fixed‐frequency heterodyne receivers indicate that the polarization, amplitude, and the temporal evolution of radiated power during the first few hundred microseconds of acceleration are in good agreement with the predicted single‐particle spectrum. These observations have been used to confirm the energy evolution and provide information about the magnitude of the transverse velocity of the beam electrons. Late‐time signal decay suggests that electrons are moving off the minor axis in a manner that is consistent...