Single Bunch Radiation Loss Studies at Slac

The experiments described in this paper have been prompted by interest in the radiation loss of relativistic electron rings passing through periodic structures. In these experiments, single bunches of electrons with intensities up to log particles per bunch are accelerated through the SLAC three-kilometer accelerator and their energy spectrum is analyzed. Although only a limited number of measurements have been conducted to date, some broad conclusions can be drawn: (a) The radiation loss for a single bunch of 10’ electrons traversing -86, 000 cavities of the accelerator is of the order of 38 MeV. (b) Between 900 MeV and 19 GeV, the radiation loss seems to be independent of energy and (c) The dependence of radiation loss on charge in the bunch appears to be linear. The paper also describes the instrumentation and equipment used to generate single bunches. Additional experiments are being planned during 1971 and 1972 which should further refine the results presented here.