Photon Tagging System at the INS Electron Synchrotron

Abstract

A photon tagging system which determines the energy of each photon in the bremsstrahlung process is constructed, and is tested using an extracted electron beam from the 1.3 GeV electron synchrotron at the Institute for Nuclear Study, University of Tokyo. The system which consists of an analyzing magnet and twenty-five tagging counters detects the recoil electrons in the energy range from 100 MeV to 350 MeV. The energy of each tagged photon has been calibrated with a total absorption type lead glass Cerenkov counter. A good agreement within the error of ±10 MeV is obtained between the energy measured by the Cerenkov counter and the one calculated from the trajectory of the recoil electron. From the first experiment using this system, it is found that the intensity of the tagged photon beam is limited to 105 photons/s.