First results concerning a crystal radiator dedicated to positron production by photons from channeled multi-Gev electrons

Starting from extensive simulations of photon emission by channeled electrons in tungsten crystals, a test experiment has been proposed. It concerns a 2 GeV electron beam impinging on a 1 mm tungsten crystal oriented along its <111> axis. Radiation measurements are ensured by a preshower detector followed by a lead-plexiglas calorimeter. Channeling data are compared to those obtained for random incidence. They can be associated with simulations using shower codes (GEANT) for estimating performances of positron sources based on this principle.<
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