Positron-production experiment using silicon and diamond crystals in the KEKB 8-GeV injector linac

Intense positron sources are widely investigated for the next-generation of linear colliders and B-factories. A new method utilizing an axially-oriented crystal as a positron-production target is one of the bright schemes since it provides a powerful photon source through channeling and coherent Bremsstrahlung processes when high-energy electrons penetrate the target. A series of positron-production experiments with heavy and light crystals hit by 4 and 8-GeV single-bunch electron beams have been carried out at the KEKB 8-GeV injector linac. This report gives the brief summary on the positron-production experiment using silicon and diamond crystals carried out in December 2002 at KEK. Laser the report based on the more precise analysis will be published elsewhere. (author)